0001193125-22-104872 | 20-F | XBRL Viewer

Corporate and group information

1.	Corporate and group information

ChipMOS TECHNOLOGIES INC. (the “Company” or “ChipMOS Taiwan”) was incorporated in the Republic of China (“ROC”) on July 28, 1997. The Company and its subsidiaries (collectively referred herein as the “Group”) are primarily engaged in the research, development, manufacturing and sale of high-integration and high-precision integrated circuits and related assembly and testing services. On April 11, 2014, the Company’s shares were listed on the Taiwan Stock Exchange (“TWSE”). On November 1, 2016, the Company’s American Depositary Shares (“ADSs”) were listed on the NASDAQ Global Select Market and traded under the ticker symbol “IMOS”.

The authorization of the consolidated financial statements

12 Months Ended

Dec. 31, 2021

The authorization of the consolidated financial statements

2.	The authorization of the consolidated financial statements

The accompanying consolidated financial statements were authorized for issuance by the Board of Directors on April 14, 2022.

Application of new and revised International Financial Reporting Standards ("IFRS"), International Accounting Standards ("IAS"), International Financial Reporting Interpretations Committee ("IFRIC") Interpretations and Standing Interpretations Committee ("SIC") Interpretations issued by the International Accounting Standards Board ("IASB"), (collectively, "IFRSs")

12 Months Ended

Dec. 31, 2021

Application of new and revised International Financial Reporting Standards (“IFRS”), International Accounting Standards (“IAS”), International Financial Reporting Interpretations Committee (“IFRIC”) Interpretations and Standing Interpretations Committee (“SIC”) Interpretations issued by the International Accounting Standards Board (“IASB”), (collectively, “IFRSs”)

Amendments to IFRSs and the new interpretation that are mandatorily effective for the current year


New Standards, Interpretations and Amendments	Effective date issued by IASB
Amendments to IFRS 4, “Extension of the Temporary Exemption from Applying IFRS 9”		January 1, 2021
Amendments to IFRS 9, IAS 39, IFRS 7, IFRS 4 and IFRS 16, “Interest Rate Benchmark Reform – Phase 2”		January 1, 2021
Amendments to IFRS 16, “Covid-19-Related Rent Concessions beyond 30 June 2021”		April 1, 2021

Based on the Group’s assessment, the above standards and interpretations have no significant impact on the Group’s financial position and financial performance.

New standards, interpretations and amendments in issue but not yet effective


New Standards, Interpretations and Amendments	Effective date issued by IASB
Amendments to IFRS 3, “Reference to the Conceptual Framework”		January 1, 2022
Amendments to IAS 16, “Property, Plant and Equipment: Proceeds before Intended Use”		January 1, 2022
Amendments to IAS 37, “Onerous Contracts – Cost of Fulfilling a Contract”		January 1, 2022
Annual Improvements to IFRS Standards 2018-2020”		January 1, 2022
Amendments to IFRS 10 and IAS 28, “Sale or Contribution of Assets between an Investor and its Associate or Joint Venture”		To be determined by IASB
IFRS 17, “Insurance Contracts”		January 1, 2023
Amendments to IFRS 17, “Insurance Contracts”		January 1, 2023
Amendment to IFRS 17, “Initial Application of IFRS 17 and IFRS 9 – Comparative Information”		January 1, 2023
Amendments to IAS 1, “Classification of Liabilities as Current or Non-current”		January 1, 2023
Amendments to IAS 1, “Disclosure of Accounting Policies”		January 1, 2023
Amendments to IAS 8, “Definition of Accounting Estimates”		January 1, 2023
Amendments to IAS 12, “Deferred Tax related to Assets and Liabilities arising from a Single Transaction”		January 1, 2023

Based on the Group’s assessment, the above standards and interpretations have no significant impact on the Group’s financial position and financial performance.

Summary of significant accounting policies

12 Months Ended

Dec. 31, 2021

Summary of significant accounting policies

4.	Summary of significant accounting policies

The significant accounting policies applied in the preparation of these accompanying consolidated financial statements are set out below. These policies have been consistently applied during the reported periods, unless otherwise stated.

Statement of compliance

The consolidated financial statements of the Group have been prepared in accordance with IFRSs as issued by the IASB.

Basis of preparation

(a)

Except for the following items, the consolidated financial statements have been prepared under the historical cost convention:

Financial assets at fair value through profit or loss (including derivative instruments).

ii)

Financial assets at fair value through other comprehensive income.

iii)

Defined benefit liabilities were recognized based on the net amount of pension fund assets less the present value of benefit obligation.

(b)

The preparation of the consolidated financial statements in conformity with IFRSs requires the use of certain critical accounting estimates. It also requires management to exercise its judgment in the process of applying the Group’s accounting policies. The areas involving a higher degree of judgment or complexity, or areas where assumptions and estimates are significant to the consolidated financial statements are disclosed in Note 4 dd).

(c)

These consolidated financial statements are presented in New Taiwan dollars (“NT$”), which is the Company’s functional currency.

Basis of consolidation

(a)

Basis for preparation of consolidated financial statements:

All subsidiaries are included in the Group’s consolidated financial statements. Subsidiaries are all entities controlled by the Group. The Group controls an entity when the Group is exposed, or has rights, to variable returns from its involvement with the entity and has the ability to affect those returns through its power over the entity. Consolidation of subsidiaries begins from the date the Group obtains control of the subsidiaries and ceases when the Group loses control of the subsidiaries.

ii)

Transactions, balances and unrealized gains or losses on transactions between companies within the Group are eliminated. Accounting policies of subsidiaries have been adjusted where necessary to ensure consistency with the policies adopted by the Group.

iii)

Profit or loss and each component of other comprehensive income are attributed to the owners of the parent and to the

non-controlling

interests. Total comprehensive income is attributed to the owners of the parent and to the

non-controlling

interests even if this results in a deficit balance in the

non-controlling

interests.

iv)

Changes in a parent’s ownership interest in a subsidiary that do not result in the parent losing control of the subsidiary (transactions with

non-controlling

interests) are accounted for as equity transactions, i.e. transactions with owners in their capacity as owners. Any difference between the amount by which the

non-controlling

interests are adjusted and the fair value of the consideration paid or received is recognized directly in equity.

When the Group loses control of a subsidiary, the Group remeasures any investment retained in the former subsidiary at its fair value. That fair value is regarded as the fair value on initial recognition of a financial asset or the cost on initial recognition of the associate or joint venture. Any difference between fair value and carrying amount is recognized in profit or loss. All amounts previously recognized in other comprehensive income in relation to the subsidiary are reclassified to profit or loss on the same basis as would be required if the related assets or liabilities were disposed of. That is, when the Group loses control of a subsidiary, all gains or losses previously recognized in other comprehensive income in relation to the subsidiary should be reclassified from equity to profit or loss, if such gains or losses would be reclassified to profit or loss when the related assets or liabilities are disposed of.

(b)

Subsidiaries included in the consolidated financial statements:

Percentage of

Ownership (%)

December 31,

Name of investor

Name of investee

Main business

Location

2020

2021

Note

The Company

ChipMOS U.S.A., Inc. (“ChipMOS USA”)

Marketing of semiconductors and electronic related products

San Jose, USA

100

The Company

ChipMOS TECHNOLOGIES (BVI) LTD.

(“ChipMOS BVI”)

Holding company

British Virgin Islands

100

ChipMOS BVI

ChipMOS SEMICONDUCTORS (Shanghai) LTD. (“ChipMOS Shanghai”)

Marketing of semiconductors and electronic related products

Shanghai, People’s Republic of China (“PRC”)

100

(c)

Subsidiaries not included in the consolidated financial statements: None.

(d)

Adjustments for subsidiaries with different statements of financial position dates: Not applicable.

(e)

No significant restrictions on the ability of subsidiaries to transfer funds to parent company.

(f)

Subsidiaries that have

non-controlling

interests that are material to the Group: None.

Foreign currency translation

Items included in the financial statements of each of the Group’s entities are measured using the currency of the primary economic environment in which the entity operates (the “functional currency”). The consolidated financial statements are presented in NT$, which is the Company’s functional currency and the Group’s presentation currency.

(a)

Foreign currency transactions and balances

Foreign currency transactions are translated into the functional currency using the exchange rates on the trade date or measurement date. Therefore, foreign exchange differences resulting from the settlement of such transactions are recognized in profit or loss in the period in which they arise.

ii)

Monetary assets and liabilities denominated in foreign currencies at the period end are

re-translated

at the exchange rates prevailing at the statements of financial position date. Exchange differences arising upon

re-translation

are recognized in profit or loss on the statements of financial position date.

iii)

Non-monetary

assets and liabilities denominated in foreign currencies held at fair value through profit or loss are

re-translated

at the exchange rates prevailing at the statements of financial position date; their exchange differences are recognized in profit or loss.

Non-monetary

assets and liabilities denominated in foreign currencies held at fair value through other comprehensive income are

re-translated

at the exchange rates prevailing at the statements of financial position date; their exchange differences are recognized in other comprehensive income. However,

non-monetary

assets and liabilities denominated in foreign currencies that are not measured at fair value are translated using the historical exchange rates at the initial dates of the transactions.

iv)

All foreign exchange differences are presented in the statement of comprehensive income under “Other gains and losses” by the nature of transactions.

(b)

Translation of foreign operations

The operating results and financial position of all the group entities, associates that have different functional currency and presentation currency are translated into the presentation currency as follows:

Assets and liabilities for each statements of financial position are translated at the exchange rates prevailing at the statements of financial position date;

ii)

Income and expenses for each statement of comprehensive income are translated at average exchange rates of that period; and

iii)

All exchange differences are recognized in other comprehensive income.

Classification of current and

non-current

assets and liabilities

(a)

Assets that meet one of the following criteria are classified as current assets:

Assets arising from operating activities that are expected to be realized, or are intended to be sold or consumed within the normal operating cycle;

ii)

Assets held mainly for trading purposes;

iii)

Assets that are expected to be realized within 12 months from the statements of financial position date;

iv)

Cash and cash equivalents, excluding restricted cash and cash equivalents and those that are to be exchanged or used to pay off liabilities more than 12 months after the statements of financial position date.

All assets that do not meet the above criteria are classified as

non-current

assets.

(b)

Liabilities that meet one of the following criteria are classified as current liabilities:

Liabilities that are expected to be settled within the normal operating cycle;

ii)

Liabilities arising mainly from trading activities;

iii)

Liabilities that are to be settled within 12 months from the statements of financial position date;

iv)

Liabilities for which the repayment date cannot be unconditionally extended to more than 12 months after the statements of financial position date. Liabilities bearing terms that could, at the option of the counterparty, result in its settlement by the issue of equity instruments do not affect its classification.

All liabilities that do not meet the above criteria are classified as

non-current

liabilities.

Cash equivalents

Cash equivalents refer to short-term, highly liquid investments that are readily convertible to known amounts of cash and are subject to an insignificant risk of changes in value (including time deposits with less than 3 months contract period). Time deposits that meet the above definition and are held for the purpose of meeting short-term cash commitments in operations are classified as cash equivalents.

Financial assets at fair value through profit or loss

(a)

Financial assets at fair value through profit or loss are financial assets that are not measured at amortized cost or fair value through other comprehensive income.

(b)

On a regular way purchase or sale basis, financial assets at fair value through profit or loss are recognized and derecognized using settlement date accounting.

(c)

At initial recognition, the Group measures the financial assets at fair value and recognizes the transaction costs in profit or loss. The Group subsequently measures the financial assets at fair value, and recognizes the gain or loss in profit or loss.

(d)

The Group recognizes the dividend income when the right to receive such payment is confirmed, inflow of the future economic benefits associated with the dividend is probable to the Group and the amount of the dividend can be measured reliably.

Financial assets at fair value through other comprehensive income

(a)

Financial assets at fair value through other comprehensive income comprise equity instruments which are not held for trading, and for which the Group has made an irrevocable election at initial recognition to recognize changes in fair value in other comprehensive income.

(b)

On a regular way purchase or sale basis, financial assets at fair value through other comprehensive income are recognized and derecognized using settlement date accounting.

(c)

At initial recognition, the Group measures the financial assets at fair value plus transaction costs. The Group subsequently measures the financial assets at fair value.

The changes in fair value of equity instruments that were recognized in other comprehensive income are reclassified to retained earnings and are not reclassified to profit or loss following the derecognition of the investment. Dividends are recognized as income when the right to receive such payment is confirmed, inflow of the future economic benefits associated with the dividend is probable to the Group and the amount of the dividend can be measured reliably.

Financial assets at amortized cost

(a)

Financial assets at amortized cost are those that meet all of the following criteria:

The objective of the Group’s business model is achieved by collecting contractual cash flows.

ii)

The financial assets’ contractual cash flows represent solely payments of principal and interest.

(b)

The Group’s time deposits which do not fall under cash equivalents are those with a short maturity period and are measured at initial investment amount as the effect of discounting is immaterial.

Accounts and notes receivable

(a)

Accounts and notes receivable entitle the Group a legal right to receive consideration in exchange for transferred goods or rendered services.

(b)

The short-term accounts and notes receivable without bearing interest are subsequently measured at initial invoice amount as the effect of discounting is immaterial.

Impairment of financial assets

For financial assets at amortized cost, at each reporting date, the Group recognizes the impairment provision for 12 months expected credit losses if there has not been a significant increase in credit risk since initial recognition or recognizes the impairment provision for the lifetime expected credit losses if such credit risk has increased since initial recognition after taking into consideration all reasonable and verifiable information that includes forecasts. On the other hand, for accounts receivable or contract assets that do not contain a significant financing component, the Group recognizes the impairment provision for lifetime expected credit losses.

Derecognition of financial assets

The Group derecognizes a financial asset when the contractual rights to receive the cash flows from the financial asset have expired.

Inventories

Inventories are initially recorded at standard costs. Cost is determined on a weighted-average cost basis. At the end of reporting period, the differences between actual costs and standard costs were allocated to inventories and cost of revenue based on an appropriate rate. Allocation of fixed production overheads is based on the normal operating capacity of the production facilities. Costs associated with underutilized capacity are expensed in the period that the cost occurs.

Inventories are valued at the lower of cost and net realizable value. Net realizable value is the estimated selling price in the ordinary course of business less the estimated costs of completion and the estimated costs necessary to make the sale. The item by item approach is used in raw materials. The amount of any write-down of inventories to net realizable value and all losses of inventories are recognized as an expense in the period the write-down or loss occurs.

Investments accounted for using equity method – associates

(a)

Associates are all entities over which the Group has significant influence but not control. In general, it is presumed that the investor has significant influence, if an investor holds, directly or indirectly 20 percent or more of the voting power of the investee. Investments in associates are accounted for using the equity method and are initially recognized at cost.

(b)

The Group’s share of its associates’ post-acquisition profits or losses is recognized in profit or loss, and its share of post-acquisition movements in other comprehensive income is recognized in other comprehensive income. When the Group’s share of losses in an associate equals or exceeds its interests in the associate, including any other unsecured receivables, the Group does not recognize further losses, unless it has incurred legal or constructive obligations or made payments on behalf of the associate.

(c)

When changes in an associate’s equity that are not recognized in profit or loss or other comprehensive income of the associate and such changes not affecting the Group’s ownership percentage of the associate, the Group recognizes the Group’s share of change in equity of the associate in “Capital surplus” in proportion to its ownership.

(d)

Unrealized gains on transactions between the Group and its associates are eliminated to the extent of the Group’s interests in the associates. Unrealized losses are also eliminated unless the transaction provides evidence of an impairment of the asset transferred. Accounting policies of associates have been adjusted where necessary to ensure consistency with the policies adopted by the Group.

(e)

In the case where an associate issues new shares and the Group does not subscribe or proportionately acquire the new shares, which results in a change in the Group’s ownership percentage of the associate while maintaining significant influence on the associate, then the Group will treat the transaction as deemed disposal and reclassify to profit or loss the proportion of the gain or loss previously recognized in other comprehensive income relating to that reduction in ownership interest where appropriate.

(f)

When the Group disposes of its investment in an associate, if it loses significant influence on this associate, the amounts previously recognized in other comprehensive income in relation to the associate are reclassified to profit or loss, on the same basis as would be required if the relevant assets or liabilities were disposed of. If it still retains significant influence on this associate, then the amounts previously recognized in other comprehensive income in relation to the associate are reclassified to profit or loss proportionately in accordance with the aforementioned approach.

Property, plant and equipment

(a)

Property, plant and equipment are initially recorded at cost. Borrowing costs incurred during the construction period are capitalized.

(b)

Subsequent costs are included in the asset’s carrying amount or recognized as a separate asset, as appropriate, only when it is probable that future economic benefits associated with the item will flow to the Group and the cost of the item can be measured reliably. The carrying amount of the replaced part is derecognized. All other repairs and maintenance are charged to profit or loss during the financial period in which they are incurred.

(c)

Land is not depreciated. Other property, plant and equipment apply cost model and are depreciated using the straight-line method to allocate their cost over their estimated useful lives. Each part of an item of property, plant and equipment with a cost that is significant in relation to the total cost of the item must be depreciated separately.

(d)

The assets’ residual values, useful lives and depreciation methods are reviewed, and adjusted if appropriate, at each financial

year-end.

If expectations for the assets’ residual values and useful lives differ from previous estimates or the patterns of consumption of the assets’ future economic benefits embodied in the assets have changed significantly, any change is accounted for as a change in estimate under IAS 8 “Accounting Policies, Change in Accounting Estimates and Errors”, from the date of the change. The estimated useful lives of property, plant and equipment are as follows:


Buildings		5 to 51 years
Machinery and equipment		2 to 8 years
Tools		2 to 4 years
Others		2 to 6 years

Leasing arrangements (lessee)

–

right-of-use assets / lease liabilities

(a)

Leases are recognized as a

right-of-use

asset and a corresponding lease liability at the date at which the leased asset is available for use by the Group. For short-term leases or leases of low value assets, lease payments are recognized as an expense on a straight-line basis over the lease term.

(b)

Lease liabilities include the net present value of the remaining lease payments at the commencement date, discounted using the incremental borrowing interest rate.

Lease payments are comprised of the following:

Fixed payments, less any lease incentives receivable;

ii)

The exercise price of a purchase option, if the lessee is reasonably certain to exercise that option.

The Group subsequently measures the lease liability at amortized cost using the interest method and recognizes interest expense over the lease term. The lease liability is remeasured and the amount of remeasurement is recognized as an adjustment to the

right-of-use

asset when there are changes in the lease term or lease payments and such changes do not arise from contract modifications.

(c)

At the commencement date, the

right-of-use

asset is stated at the amount of the initial measurement of lease liability. The

right-of-use

asset is measured subsequently using the cost model and is depreciated from the commencement date to the earlier of the end of the asset’s useful life or the end of the lease term. When the lease liability is remeasured, the amount of remeasurement is recognized as an adjustment to the

right-of-use

asset.

Impairment of

non-financial

assets

The Group assesses at each statements of financial position date the recoverable amounts of those assets where there is an indication that they are impaired. An impairment loss is recognized for the amount by which the asset’s carrying amount exceeds its recoverable amount. The recoverable amount is the higher of an asset’s fair value less costs to sell or value in use. When the circumstances or reasons for recognizing impairment loss for an asset in prior years no longer exist or diminish, the impairment loss is reversed. The increased carrying amount due to reversal should not be more than what the depreciated or amortized historical cost would have been if the impairment had not been recognized.

Loans

Loans comprise long-term and short-term bank loans. Loans are recognized initially at fair value, net of transaction costs incurred. Loans are subsequently stated at amortized cost; any difference between the proceeds (net of transaction costs) and the redemption value is recognized as interest expense in profit or loss over the period of the loans using the effective interest method.

Accounts and notes payable

(a)

Accounts payable are liabilities for purchases of raw materials, goods or services and notes payable are those resulting from operating and

non-operating

activities.

(b)

The short-term accounts and notes payable without bearing interest are subsequently measured at initial invoice amount as the effect of discounting is immaterial.

Derecognition of financial liabilities

A financial liability is derecognized when the obligation specified in the contract is either discharged or cancelled or expires.

Provisions for deficiency compensation

Provisions are recognized when the Group has a present legal or constructive obligation as a result of past events, and it is probable that an outflow of economic resources will be required to settle the obligation and the amount of the obligation can be reliably estimated. Provisions are measured at the present value of the expenditures expected to be required to settle the obligation on the statements of financial position date, which is discounted using a

pre-tax

discount rate that reflects the current market assessments of the time value of money and the risks specific to the obligation. When discounting is used, the increase in the provision arising from the passage of time is recognized as interest expense. Provisions are not recognized for future operating losses.

Employee benefits

(a)

Short-term employee benefits

Short-term employee benefits are measured at the undiscounted amount of the benefits expected to be paid in respect of service rendered by employees and should be recognized as expenses when the employees render service.

(b)

Pensions

Defined contribution plans

For defined contribution plans, the contributions are recognized as pension expenses when they are due on an accrual basis. Prepaid contributions are recognized as an asset to the extent of a cash refund or a reduction in future payments.

ii)

Defined benefit plans

Net obligation under a defined benefit plan is defined as the present value of an amount of pension benefits that employees will receive on retirement for their services with the Group in the current period or prior periods. The liability recognized in the statements of financial position in respect of defined benefit pension plans is the present value of the defined benefit obligation at the statements of financial position date less the fair value of plan assets. The net defined benefit obligation is calculated annually by independent actuaries using the projected unit credit method. The discount rate is determined by using the interest rates of government bonds that are denominated in the currency in which the benefits will be paid, and that have terms to maturity approximating to the terms of the related pension liability.

Remeasurements arising on defined benefit plans are recognized in other comprehensive income in the period in which they arise and are recorded as retained earnings.

Past service costs are recognized immediately in profit or loss.

(c)

Termination benefits

Termination benefits are employee benefits provided in exchange for the termination of employment as a result from either the Group’s decision to terminate an employee’s employment before the normal retirement date, or an employee’s decision to accept an offer of redundancy benefits in exchange for the termination of employment. The Group recognizes an expense as it can no longer withdraw an offer of termination benefits, or it recognizes related restructuring costs, whichever is earlier. Benefits that are expected to be due more than 12 months after statements of financial position date shall be discounted to their present value.

(d)

Employees’ compensation and directors’ remuneration

Employees’ compensation and directors’ remuneration are recognized as expenses and liabilities, provided that such recognition is required under legal obligation or constructive obligation and those amounts can be reliably estimated. Any difference between the resolved amounts and the subsequently actual distributed amounts is accounted for as changes in estimates. If employee compensation is paid by shares, the Company calculates the number of shares based on the closing price at the previous day of the board meeting resolution.

Employee share-based payments

Restricted shares

(a)

Restricted shares issued to employees are measured at the fair value of the equity instruments granted at the grant date, and are recognized as compensation cost over the vesting period.

(b)

For restricted shares where those shares do not restrict distribution of dividends to employees and employees are not required to return the dividends received if they resign during the vesting period, the Group recognizes the fair value of the dividends received by employees who are expected to resign during the vesting period as a compensation cost at the date the dividends were declared.

(c)

For restricted shares where employees do not need to pay to acquire those shares, if an employee resigns during the vesting period, the Group will recover and retire those shares at no cost.

Income tax

(a)

The income tax expense for the period comprises current and deferred tax. Income tax is recognized in profit or loss, except to the extent that it relates to items recognized in other comprehensive income or items recognized directly in equity, in which cases the income tax is recognized in other comprehensive income or equity.

(b)

The current income tax expense is calculated on the basis of the tax laws enacted or substantively enacted at the statements of financial position date in the countries where the Group and its subsidiaries operate and generate taxable income. Management periodically evaluates positions taken in tax returns with respect to situations in accordance with applicable tax regulations. It establishes provisions where appropriate based on the amounts expected to be paid to the tax authorities. An additional income tax is levied on the unappropriated retained earnings and is recorded as income tax expense in the year the profit generated.

(c)

Deferred tax is recognized, using the balance sheet liability method, on temporary differences arising between the tax bases of assets and liabilities and their carrying amounts in the consolidated statements of financial position. However, the deferred tax is not accounted for if it arises from initial recognition of an asset or liability in a transaction other than a business combination that at the time of the transaction affects neither accounting nor taxable profit or loss. Deferred tax is provided on temporary differences arising on investments in subsidiaries and associates, except where the timing of the reversal of the temporary difference is controlled by the Group and it is probable that the temporary difference will not reverse in the foreseeable future. Deferred tax is determined using tax rates (and laws) that have been enacted or substantially enacted at the statements of financial position date and are expected to apply when the related deferred tax asset is realized or the deferred tax liability is settled.

(d)

Deferred tax assets are recognized only to the extent that it is probable that future taxable profit will be available against which the temporary differences can be utilized. At each statements of financial position date, unrecognized and recognized deferred tax assets are reassessed.

(e)

A deferred tax asset shall be recognized for the carryforward of unused tax credits resulting from equity investments to the extent that it is possible that future taxable profit will be available against which the unused tax credits can be utilized.

(f)

If a change in tax rate is enacted or substantively enacted, the Group recognizes the effect of the change immediately in the period in which the change occurs. The effect of the change on items recognized outside profit or loss is recognized in other comprehensive income or equity while the effect of the change on items recognized in profit or loss is recognized in profit or loss.

Capital stock

(a)

Ordinary shares are classified as equity. Incremental costs directly attributable to the issue of new shares in net proceeds of tax are shown in equity as a deduction.

(b)

Where the Company repurchases the Company’s shares that have been issued, the consideration paid, including any directly attributable incremental costs (net of income taxes) is deducted from equity attributable to the Company’s equity holders. Where such shares are subsequently reissued, the difference between their book value and any consideration received, net of any directly attributable incremental transaction costs and the related income tax effects, is included in equity attributable to the Company’s equity holders.

Dividends

Dividends are recorded in the Company’s financial statements in the period in which they are resolved by the Company’s shareholders. Cash dividends are recorded as liabilities; stock dividends are recorded as stock dividends to be distributed and are reclassified to ordinary shares on the effective date of new shares issuance.

aa)

Revenue recognition

(a)

The Group is primarily engaged in the customized assembly and testing services of high-integration and high-precision integrated circuits based on customer’s specification demand to create or enhance the product. When providing assembly and testing services, the Group considers:

Customer controls the provided raw materials and the Group receives the instruction from the customer on providing assembly and testing services and subsequent treatments.

ii)

The Group provides assembly and testing services to create or enhance an asset which is solely provided and controlled by the customer. The Group has no right to transfer the asset for another use.

As the asset ownership belongs to the customer, who bears the significant risk and rewards and rights on the use of the asset, the Group recognizes assembly and testing service revenue based on the progress towards completion of performance obligation during the service period.

(b)

The progress towards completion on assembly services, services for Liquid Crystal Display and other Flat-Panel Display Driver Semiconductors (“LCDD”) and Bumping are measured by the actual input costs relative to estimate total expected input costs. The progress towards completion on testing services is measured by the actual incurred testing volume. The Group provides assembly and testing services based on customer’s specification, thus, the input costs incurred to assembly and testing volume completed in testing services are not linear over the duration of these services. Customer payment on assembly and testing services is based on predetermined payment schedule. A contract asset is recognized when the Group provides services in excess of customer’s payment.

bb)

Government grants

Government grants are recognized at their fair value only when there is reasonable assurance that the Group will comply with any conditions attached to the grants will be received. Government grants are recognized in profit or loss on a systematic basis over the periods in which the Group recognizes expenses for the related costs for which the grants are intended to compensate. Government grants related to property, plant and equipment are recognized as

non-current

liabilities and are amortized to profit or loss over the estimated useful lives of the related assets using straight-line method.

cc)

Operating segments

Operating segments are reported in a manner consistent with the internal reporting provided to the chief operating decision maker. The Group’s chief operating decision maker, who is responsible for allocating resources and assessing performance of the operating segments, has been identified as the Chairman of the Board of Directors that makes strategic decisions.

dd)

Critical accounting judgments, estimates and key sources of assumption uncertainty

The preparation of the accompanying consolidated financial statements requires management to make critical judgments in applying the Group’s accounting policies and make critical assumptions and estimates concerning future events. Assumptions and estimates may differ from the actual results and are continually evaluated and adjusted based on historical experience and other factors. Such assumptions and estimates have a significant risk of causing a material adjustment to the carrying amounts of assets and liabilities within the next financial year; and the related information is addressed below:

Critical accounting estimates and assumptions

Revenue recognition

The Group recognizes revenue from services for assembly, LCDD and Bumping based on the progress towards completion of performance obligation during the service period. The Group estimates total expected input costs based on historical experience and measures the progress towards completion by the actual input costs relative to the total expected input costs.

Translation into U.S. dollar amounts

12 Months Ended

Dec. 31, 2021

Translation into U.S. dollar amounts

5.	Translation into U.S. dollar amounts

The Company maintains its accounts and expresses its consolidated financial statements in New Taiwan dollars. For convenience purposes, U.S. dollar amounts presented in the accompanying consolidated financial statements have been translated from New Taiwan dollars to U.S. dollars at the noon buying rate in the City of New York for cable transfers as certified for customs purposes by the Federal Reserve Bank of New York as of December 30, 2021, which was NT$27.74 to US$1.00. These convenience translations should not be construed as representations that the New Taiwan dollar amounts have been, or could in the future be, converted into U.S. dollars at this or any other rate of exchange.

Cash and cash equivalents

12 Months Ended

Dec. 31, 2021

Cash and cash equivalents

6.	Cash and cash equivalents


	December 31, 2020		December 31, 2021
	NT$000		NT$000
Cash on hand and petty cash		470		450
Checking accounts and demand deposits		2,609,421		2,683,977
Time deposits		1,503,760		3,221,749

		4,113,651		5,906,176

The Group transacts with a variety of financial institutions all with high credit quality to disperse credit risk, so it expects that the probability of counterparty default is remote.

No cash and cash equivalents of the Group were pledged to others.

Financial assets at fair value through profit or loss

12 Months Ended

Dec. 31, 2021

Financial assets at fair value through profit or loss

7.	Financial assets at fair value through profit or loss


	December 31, 2020			December 31, 2021
	NT$000			NT$000
Current:
Financial assets mandatorily measured at fair value through profit or loss
Listed stocks		46,512			339,679
Valuation adjustment		6,608			20,281

		53,120			359,960

Non-current:
Financial assets mandatorily measured at fair value through profit or loss
Foreign partnership interests		10,940			—
Valuation adjustment		(572	)		—

		10,368			—

Amounts recognized in profit or loss in relation to the financial assets at fair value through profit or loss are listed below:


	Year ended December 31,
	2019			2020			2021
	NT$000			NT$000			NT$000
Financial assets mandatorily measured at fair value through profit or loss
Beneficiary certificates*		1,750			18,077			2,530
Listed stocks		—			6,608			13,673
Foreign partnership interests		(433	)		(670	)		(941	)

		1,317			24,015			15,262

Beneficiary certificates represent money market funds the Company held during the reporting period. As of December 31, 2019, 2020 and 2021, there were no beneficiary certificates classified as current financial assets at fair value through profit or loss (“FVTPL”).

No financial assets at FVTPL were pledged to others.

Information relating to price risk of financial assets at FVTPL is provided in Note 43.

Financial assets at amortized cost

12 Months Ended

Dec. 31, 2021

Financial assets at amortized cost

8.	Financial assets at amortized cost


	December 31, 2020		December 31, 2021
	NT$000		NT$000
Current:
Time deposits		206,482		29,239

Non-current:
Restricted bank deposits		48,319		37,539

Amounts recognized in profit or loss in relation to financial assets at amortized cost are listed below:


	Year ended December 31,
	2019		2020		2021
	NT$000		NT$000		NT$000
Interest income		4,467		2,206		1,187

Without taking into account any collateral held or other credit enhancements, the maximum exposure to credit risk in respect of the amount that best represents the financial assets at amortized cost held by the Group is the carrying amount at the end of each reporting period.

Information about the financial assets at amortized cost that were pledged to others as collateral is provided in Note 38.

Information relating to credit risk of financial assets at amortized cost is provided in Note 43.

Accounts receivable

12 Months Ended

Dec. 31, 2021

Accounts receivable

9.	Accounts receivable


	December 31, 2020			December 31, 2021
	NT$000			NT$000
Accounts receivable		5,365,776			6,346,156
Less: Loss allowance		(1,620	)		(1,910	)

		5,364,156			6,344,246

The Group’s credit term granted to customers is 30~90 days. Receivables do not bear interest. The loss allowance is determined based on the credit quality of customers. Information relating to credit risk is provided in Note 43.

The aging analysis of accounts receivable based on past due date are as follows:


	December 31, 2020		December 31, 2021
	NT$000		NT$000
Current		5,272,208		6,327,791
Within 1 month		93,568		18,365

		5,365,776		6,346,156

As of December 31, 2020 and 2021, accounts receivable were all from contracts with customers. And as of January 1, 2020, the balance of accounts receivable from contracts with customers was NT$4,452,904 thousand.

Without taking into account of any collateral held or other credit enhancements, the amount that best reflects the Group’s maximum exposure to credit risk in respect of the accounts receivable is the carrying amount at the end of each reporting period.

No accounts receivable of the Group were pledged to others.

Inventories

12 Months Ended

Dec. 31, 2021

Inventories

10.	Inventories

December 31, 2020

Cost

Allowance for

impairment losses

Carrying amount

NT$000

Raw materials

2,181,890

(79,815

)

2,102,075

December 31, 2021

Cost

Allowance for

impairment losses

Carrying amount

NT$000

Raw materials

3,328,763

(121,586

)

3,207,177

The cost of inventories recognized as an expense for the year:


	Year ended December 31,
	2019		2020		2021
	NT$000		NT$000		NT$000
Cost of revenue		16,372,032		17,957,568		20,103,735
Loss on abandonment		12,369		5,323		552
Allowance for inventory valuation and obsolescence loss		27,341		16,317		41,770

		16,411,742		17,979,208		20,146,057

Allowance for inventory valuation and obsolescence loss was recognized due to the change in net realizable value.

No inventories of the Group were pledged to others.

Non-current financial assets at fair value through other comprehensive income

12 Months Ended

Dec. 31, 2021

Non-current financial assets at fair value through other comprehensive income

11.	Non-current financial assets at fair value through other comprehensive income


	December 31, 2020		December 31, 2021
	NT$000		NT$000
Designation of equity instruments
Foreign unlisted stocks		38,534		38,534
Valuation adjustment		223,473		345,987

		262,007		384,521

Based on the Group’s business model, the foreign unlisted stocks held for strategic investments were elected to classify as “Financial assets at fair value through other comprehensive income”. As of December 31, 2020 and 2021, the fair value of aforementioned investments is the carrying amount at the end of each reporting period.

Amounts recognized in other comprehensive income in relation to the financial assets at fair value through other comprehensive income are listed below:


	Year ended December 31,
	2019			2020		2021
	NT$000			NT$000		NT$000
Financial assets at fair value through other comprehensive income
Foreign unlisted stocks		(52,549	)		140,199		122,514

No financial assets at fair value through other comprehensive income were pledged to others.

Information about fair value measurement is provided in Note 43 b).

Investments accounted for using equity method

12 Months Ended

Dec. 31, 2021

Investments accounted for using equity method [abstract]

Investments accounted for using equity method

12.	Investments accounted for using equity method


Associates	December 31, 2020		December 31, 2021
	NT$000		NT$000
JMC ELECTRONICS CO., LTD. (“JMC”)		250,769		304,437
Unimos Microelectronics (Shanghai) Co., Ltd. (“Unimos Shanghai”)		3,020,908		3,596,012

		3,271,677		3,900,449

The carrying amount of the Group’s interests in all individually immaterial associates and the Group’s share of the operating results are summarized below:

As of December 31, 2020 and 2021, the carrying amount of the Group’s individually immaterial associates amounted to $3,271,677 thousand and $3,900,449 thousand, respectively.


	Year ended December 31,
	2019			2020			2021
	NT$000			NT$000			NT$000
(Loss) profit for the year from continuing operations		(154,926	)		(147,329	)		625,733
Other comprehensive income, net of income tax		5,732			23,143			28,843

Total comprehensive (loss) income		(149,194	)		(124,186	)		654,576

JMC has quoted market prices. As of December 31, 2020 and 2021, the fair value was NT$454,010 thousand and NT$468,950 thousand, respectively.

To further strengthen financial structure, increase balance of working capital and reduce debt ratio, the Company’s Board of Directors adopted a resolution on April 2, 2019 to dispose of 9,100,000 common shares of JMC, which reduced the shareholding of equity investment in JMC to 10%. The disposal of shares was completed on April 8, 2019 for cash consideration of NT$1,180,179 thousand, and the Company recognized gain on disposal of investment in associates amounted to NT$973,609 thousand. JMC is still recognized as investment accounted for using equity method given that the Company retains significant influence by holding one seat in JMC’s Board of Directors.

Property, plant and equipment, net

12 Months Ended

Dec. 31, 2021

Property, plant and equipment, net

13.	Property, plant and equipment, net


	2019
	Land		Buildings			Machinery and equipment			Tools			Others			Construction in progress and equipment to be inspected			Total
	NT$000		NT$000			NT$000			NT$000			NT$000			NT$000			NT$000
January 1
Cost		452,738		10,254,531			48,274,171			4,402,711			2,610,893			1,069,892			67,064,936
Accumulated depreciation and impairment		—		(6,345,800	)		(38,042,078	)		(3,660,532	)		(2,196,905	)		—			(50,245,315	)

		452,738		3,908,731			10,232,093			742,179			413,988			1,069,892			16,819,621

January 1		452,738		3,908,731			10,232,093			742,179			413,988			1,069,892			16,819,621
Effects on initial application of IFRS 16		—		—			—			—			(31,904	)		—			(31,904	)

Adjusted balance at January 1		452,738		3,908,731			10,232,093			742,179			382,084			1,069,892			16,787,717
Additions		—		116,238			2,334,358			781,465			224,287			1,440,308			4,896,656
Disposals		—		—			(16,033	)		(9,336	)		(416	)		—			(25,785	)
Reclassifications		—		455,792			1,111,715			7,880			25,042			(1,573,811	)		26,618
Depreciation expenses		—		(384,832	)		(2,489,070	)		(625,712	)		(196,201	)		—			(3,695,815	)
Impairment losses		—		—			(9,938	)		—			—			—			(9,938	)
Exchange adjustment		—		—			(4	)		—			(5	)		—			(9	)

December 31		452,738		4,095,929			11,163,121			896,476			434,791			936,389			17,979,444

December 31
Cost		452,738		10,821,972			51,244,512			5,008,321			1,937,755			936,389			70,401,687
Accumulated depreciation and impairment		—		(6,726,043	)		(40,081,391	)		(4,111,845	)		(1,502,964	)		—			(52,422,243	)

		452,738		4,095,929			11,163,121			896,476			434,791			936,389			17,979,444


	2020
	Land		Buildings			Machinery and equipment			Tools			Others			Construction in progress and equipment to be inspected			Total
	NT$000		NT$000			NT$000			NT$000			NT$000			NT$000			NT$000
January 1
Cost		452,738		10,821,972			51,244,512			5,008,321			1,937,755			936,389			70,401,687
Accumulated depreciation and impairment		—		(6,726,043	)		(40,081,391	)		(4,111,845	)		(1,502,964	)		—			(52,422,243	)

		452,738		4,095,929			11,163,121			896,476			434,791			936,389			17,979,444

January 1		452,738		4,095,929			11,163,121			896,476			434,791			936,389			17,979,444
Additions		—		132,572			592,565			409,832			142,776			2,855,870			4,133,615
Disposals		—		—			(8,940	)		(3,121	)		(7,297	)		—			(19,358	)
Reclassifications		—		258,421			2,336,238			398,798			159,195			(3,152,652	)		—
Depreciation expenses		—		(394,636	)		(2,734,667	)		(749,624	)		(220,066	)		—			(4,098,993	)
Exchange adjustment		—		—			(20	)		—			(2	)		—			(22	)

December 31		452,738		4,092,286			11,348,297			952,361			509,397			639,607			17,994,686

December 31
Cost		452,738		11,212,129			53,246,474			5,451,547			2,185,299			639,607			73,187,794
Accumulated depreciation and impairment		—		(7,119,843	)		(41,898,177	)		(4,499,186	)		(1,675,902	)		—			(55,193,108	)

		452,738		4,092,286			11,348,297			952,361			509,397			639,607			17,994,686


	2021
	Land		Buildings			Machinery and equipment			Tools			Others			Construction in progress and equipment to be inspected			Total
	NT$000		NT$000			NT$000			NT$000			NT$000			NT$000			NT$000
January 1
Cost		452,738		11,212,129			53,246,474			5,451,547			2,185,299			639,607			73,187,794
Accumulated depreciation and impairment		—		(7,119,843	)		(41,898,177	)		(4,499,186	)		(1,675,902	)		—			(55,193,108	)

		452,738		4,092,286			11,348,297			952,361			509,397			639,607			17,994,686

January 1		452,738		4,092,286			11,348,297			952,361			509,397			639,607			17,994,686
Additions		—		1,345			11,829			407			189			6,538,932			6,552,702
Disposals		—		—			(66,873	)		(9,502	)		—			—			(76,375	)
Reclassifications		—		673,208			4,890,400			690,346			241,656			(6,495,610	)		—
Depreciation expenses		—		(423,283	)		(2,896,612	)		(795,622	)		(239,515	)		—			(4,355,032	)
Impairment losses		—		—			(4,843	)		—			—			—			(4,843	)
Exchange adjustment		—		—			(13	)		—			(4	)		—			(17	)

December 31		452,738		4,343,556			13,282,185			837,990			511,723			682,929			20,111,121

December 31
Cost		452,738		11,877,419			57,176,339			5,574,316			2,345,204			682,929			78,108,945
Accumulated depreciation and impairment		—		(7,533,863	)		(43,894,154	)		(4,736,326	)		(1,833,481	)		—			(57,997,824	)

		452,738		4,343,556			13,282,185			837,990			511,723			682,929			20,111,121

Amount of borrowing costs capitalized as part of property, plant and equipment and the range of the interest rates for such capitalization are as follows:


	Year ended December 31,
	2019			2020			2021
	NT$000			NT$000			NT$000
Amount of interest capitalized		15,114			9,762			11,193
Range of the interest rates for capitalization		1.7822	%		1.4909	%		1.1358	%

Information about the property, plant and equipment that were pledged to others as collaterals is provided in Note 38.

Leasing arrangements - leasee

12 Months Ended

Dec. 31, 2021

Presentation of leases for lessee [abstract]

Leasing arrangements - leasee

14.	Leasing arrangements - lessee

The Group leases various assets, including land, buildings, machinery and equipment, and others. Lease agreements are typically made for periods of 1 to 30 years. Lease terms are negotiated on an individual basis and contain a wide range of different terms and conditions. The lease agreements do not impose covenants, but leased assets may not be used as security for borrowing purposes.

The carrying amount of

right-of-use

assets and the depreciation expenses are as follows:


	December 31, 2020		December 31, 2021
	Carrying amount		Carrying amount
	NT$000		NT$000
Land		636,261		616,458
Buildings		19,044		10,946
Machinery and equipment		203,249		204,484
Others		515		3,917

		859,069		835,805


	Year ended December 31,
	2019		2020		2021
	Depreciation expenses		Depreciation expenses		Depreciation expenses
	NT$000		NT$000		NT$000
Land		22,657		20,938		20,486
Buildings		7,113		7,819		9,870
Machinery and equipment		4,520		46,225		247,090
Others		1,809		1,544		1,634

		36,099		76,526		279,080

For the years ended December 31, 2020 and 2021, additions to

right-of-use

assets were NT$261,798 thousand and NT$433,768 thousand, respectively.

The information on profit or loss accounts relating to lease contracts is as follows:


	Year ended December 31,
	2019		2020		2021
	NT$000		NT$000		NT$000
Items affecting profit or loss
Interest expense on lease liabilities		14,349		13,442		15,245
Expense on short-term lease contracts		230,589		202,782		143,791

For the years ended December 31, 2019, 2020 and 2021, the Group’s total cash outflow for leases were NT$273,709 thousand, NT$274,727 thousand and NT$448,290 thousand, respectively.

Short-term bank loans

12 Months Ended

Dec. 31, 2021

Short Term Borrowings Abstract [Abstract]

Short-term bank loans

15.	Short-term bank loans


Type of loans	December 31, 2020		December 31, 2021
	NT$000		NT$000
Bank loans
Unsecured bank loans		—		731,751

Interest rate range		—		0.6604%~0.7394	%

Unused credit lines of short-term bank loans
NT$000		3,251,000		2,918,249

US$000		90,000		85,025

Accounts payable

12 Months Ended

Dec. 31, 2021

Disclosure Of Detailed Information Of Trade And Other Payable Explanatory [Abstract]

Accounts payable

16.	Accounts payable


	December 31, 2020		December 31, 2021
	NT$000		NT$000
Accounts payable		766,805		765,403
Estimated accounts payable		200,016		246,988

		966,821		1,012,391

Other Payables

12 Months Ended

Dec. 31, 2021

Other Payables

17.	Other payables


	December 31, 2020		December 31, 2021
	NT$000		NT$000
Payables to contractors and equipment suppliers		1,145,359		1,816,555
Salaries and bonuses payable		788,720		829,762
Employees’ compensation payable		332,080		673,387
Directors’ remuneration payable		16,604		25,690
Pension payable		15,159		16,600
Interest payable		1,958		3,277
Other expense payable		949,523		1,013,168

		3,249,403		4,378,439

Long-term bank loans

12 Months Ended

Dec. 31, 2021

Long-term bank loans

18.	Long-term bank loans


Type of loans	Period and payment term	December 31, 2020			December 31, 2021
		NT$000			NT$000
Syndicated bank loan	Borrowing period is from May 30, 2018 to May 30, 2023; interest is repayable monthly; principal is repayable semi-annually from November 30, 2018		3,310,000			54,000
Government granted bank loans	Borrowing period is from March 11, 2020 to November 15, 2031; interest is repayable monthly; principal is repayable monthly from March 15, 2023		4,505,000			9,463,131
Less: Fee on syndicated bank loan			(17,223	)		(10,026	)
Less: Unamortized interest on government granted bank loans			(64,212	)		(93,740	)
Less: Current portion (fee included)			(748,353	)		(46,826	)

			6,985,212			9,366,539

Interest rate range			0.65%~1.7895	%		0.45%~1.7895	%

Unused credit lines of long-term bank loan NT$000			11,239,000			8,776,868

On January 1,

2019

, Ministry of Economic Affairs, ROC (“MOEA”) implemented the “Action Plan for Welcoming Overseas Taiwanese Businesses to Return to Invest in Taiwan” and companies are subsidized with preferential interest loans for qualified investment projects. The Company has obtained the qualification from the MOEA, and signed loan agreements with financial institutions during January 2020 and November 2021 with the line of credit amounted to NT$14.64 billion and terms from seven to ten years. Funding from these loans was used to invest in machineries, equipment and plant expansions and broaden the Company’s working capital.

On May 15, 2018, the Company entered into a syndicated loan with eleven banks in Taiwan, including Taiwan Cooperative Bank, in the amount of NT$12 billion with a term of five years. Funding from this syndicated loan was used to repay the existing debt of financial institutions and broaden the Company’s working capital. Pursuant to the syndicated loan agreement, the Group is required to maintain certain financial ratios including current ratio, interest protection multiples and debt to equity ratio during the loan periods.

Information about the items that are pledged to others as collaterals for long-term bank loans is provided in Note 38.

Pensions

12 Months Ended

Dec. 31, 2021

Pensions

19.

Pensions

Defined Benefit Plans

The Company has a defined benefit pension plan in accordance with the Labor Standards Act, covering all regular employees’ service years prior to the enforcement of the Labor Pension Act on July 1, 2005 and service years thereafter of employees who chose to continue to be subject to the pension mechanism under the Labor Standards Act. Under the defined benefit pension plan, two units are accrued for each year of service for the first 15 years and one unit for each additional year thereafter, subject to a maximum of 45 units. Pension benefits are based on the number of units accrued and the average monthly salaries and wages of the last 6 months prior to retirement. The Company contributes monthly an amount equal to 2% of the employees’ monthly salaries and wages to the pension fund deposited with the Bank of Taiwan, the trustee, under the name of the independent pension fund committee. Also, the Company would assess the balance in the aforementioned labor pension reserve account by the end of every year. If the account balance is insufficient to pay the pension calculated by the aforementioned method, to the employees expected to be qualified for retirement next year, the Company will make contributions to cover the deficit by March of following year.

(a)

The amounts recognized in the statements of financial position are as follows:


	December 31, 2020			December 31, 2021
	NT$000			NT$000
Present value of defined benefit obligations		(943,391	)		(959,677	)
Fair value of plan assets		431,740			456,389

Net defined benefit liability		(511,651	)		(503,288	)

(b)

Movements in net defined benefit liability are as follows:


	2019
	Present value of defined benefit obligations			Fair value of plan assets			Net defined benefit liability
	NT$000			NT$000			NT$000
January 1		(910,081	)		389,316			(520,765	)
Current services cost		(332	)		—			(332	)
Interest (expense) income		(11,170	)		4,831			(6,339	)

		(921,583	)		394,147			(527,436	)

Remeasurements:
Return on plan assets (excluding amounts included in interest income or expense)		—			12,601			12,601
Financial assumption movement effect		(27,993	)		—			(27,993	)
Experience adjustments		36,308			—			36,308

		8,315			12,601			20,916

Pension fund contribution		—			26,413			26,413
Paid pension		12,109			(12,109	)		—

December 31		(901,159	)		421,052			(480,107	)


	2020
	Present value of defined benefit obligations			Fair value of plan assets			Net defined benefit liability
	NT$000			NT$000			NT$000
January 1		(901,159	)		421,052			(480,107	)
Current services cost		(263	)		—			(263	)
Interest (expense) income		(8,835	)		4,171			(4,664	)

		(910,257	)		425,223			(485,034	)

Remeasurements:
Return on plan assets (excluding amounts included in interest income or expense)		—			12,568			12,568
Financial assumption movement effect		(57,180	)		—			(57,180	)
Experience adjustments		(7,378	)		—			(7,378	)

		(64,558	)		12,568			(51,990	)

Pension fund contribution		—			25,373			25,373
Paid pension		31,424			(31,424	)		—

December 31		(943,391	)		431,740			(511,651	)


	2021
	Present value of defined benefit obligations			Fair value of plan assets			Net defined benefit liability
	NT$000			NT$000			NT$000
January 1		(943,391	)		431,740			(511,651	)
Current services cost		(237	)		—			(237	)
Interest (expense) income		(4,629	)		2,137			(2,492	)

		(948,257	)		433,877			(514,380	)

Remeasurements:
Return on plan assets (excluding amounts included in interest income or expense)		—			5,613			5,613
Impact on changes in demographic assumptions		(20,022	)		—			(20,022	)
Financial assumption movement effect		23,757			—			23,757
Experience adjustments		(24,347	)		—			(24,347	)

		(20,612	)		5,613			(14,999	)

Pension fund contribution		—			26,091			26,091
Paid pension		9,192			(9,192	)		—

December 31		(959,677	)		456,389			(503,288	)

(c)

The Bank of Taiwan was commissioned to manage the fund of the Company’s defined benefit pension plan in accordance with the fund’s annual investment and utilization plan and the “Regulations for Revenues, Expenditures, Safeguard and Utilization of the Labor Retirement Fund” (Article 6: The scope of utilization for the fund includes deposit in domestic or foreign financial institutions, investment in domestic or foreign listed,

over-the-counter,

or private placement equity securities, investment in domestic or foreign real estate securitization products, etc.). With regard to the utilization of the fund, its minimum earnings in the annual distributions on the final financial statements shall be no less than the earnings attainable from the amounts accrued from

two-year

time deposits with the interest rates offered by local banks. If the earnings are less than aforementioned rates, government shall make payment for the deficit after being authorized by the authority. The Company has no right to participate in managing and operating that fund and hence the Company is unable to disclose the classification of the fair value of plan asset in accordance with IAS 19 “Employee Benefits” paragraph 142. The composition of fair value of plan assets as of December 31, 2020 and 2021 is given in the Annual Labor Retirement Fund Utilization Report announced by the government.

(d)

The principal actuarial assumptions used were as follows:


	Year ended December 31,
	2020			2021
Discount rate		0.50	%		0.70	%

Future salary increase		3.50	%		3.50	%

Assumptions regarding future mortality are set based on actuarial advice in accordance with published statistics and experience in each territory.

The present value of defined benefit obligations is affected by the change in actuarial assumption. The analysis was as follows:


	Discount rate					Future salary increase
	Increase 0.25%			Decrease 0.25%		Increase 0.25%		Decrease 0.25%
	NT$000			NT$000		NT$000		NT$000
December 31, 2020
Effect on present value of defined benefit obligations		(29,114	)		30,434		29,471		(28,365	)

December 31, 2021
Effect on present value of defined benefit obligations		(28,574	)		29,825		28,941		(27,893	)

The sensitivity analysis above is based on a change in an assumption while holding all other assumptions constant. In practice, changes in some of the assumptions may be correlated. The method of sensitivity analysis and the method of calculating net defined benefit liability in the statements of financial position are the same.

The methods and types of assumptions used in preparing the sensitivity analysis remain unchanged from previous period.

(e)

Expected contributions to the defined benefit pension plans of the Company for the year ending December 31, 2022 amounts to NT$

27,00

5 thousand.

(f)

As of December 31, 2021, the weighted average duration of that retirement plan is 12.2 years. The analysis of timing of the future pension payment was as follows:


	December 31, 2021
	NT$000
Within 1 year		36,762
1-2 years		36,346
2-5 years		126,806
5-10 years		178,998

		378,912

Defined Contribution Plans

(a)

Effective from July 1, 2005, the Company established a defined contribution pension plan (“New Plan”) under the Labor Pension Act, covering all regular employees with ROC nationality. Under the New Plan, the Company contributes monthly an amount based on 6% of the employees’ monthly salaries and wages to the employees’ individual pension accounts at the Bureau of Labor Insurance. The benefits accrued are paid monthly or in lump sum upon termination of employment. The pension costs under defined contribution pension plans of the Company for the years ended December 31, 2019, 2020 and 2021 were NT$187,502 thousand, NT$184,562 thousand and NT$197,076 thousand, respectively.

(b)

According to the defined contribution pension plan stipulated by PRC, ChipMOS Shanghai contributes monthly on amount based on a certain percentage of the local employees’ monthly salaries and wages. The contribution percentage were both 16% for the years ended December 31, 2020 and 2021. The pension of each employee is managed by the government and ChipMOS Shanghai has no further obligations except the monthly contribution. The pension costs under defined contribution pension plan of ChipMOS Shanghai for the years ended December 31, 2020 and 2021 were nil and $209 thousand, respectively.

Share-based payments

12 Months Ended

Dec. 31, 2021

Share-based payments

20.	Share-based payments

Restricted shares

On July 14, 2015, the Company’s Board of Directors approved the issuance of restricted shares. The record dates for the shares issuance were July 21, 2015 and May 10, 2016. The relevant information is as follows:

Type of

arrangement

Grant
date

Share price
on grant date
(in NT$)

Number of
shares
(in thousands)

Contract
period

Vesting condition

Restricted shares award agreement

July 21,
2015

36.1

15,752

3 years

Meet service and performance conditions

Restricted shares award agreement

May 10,
2016

30.6

1,548

3 years

Meet service and performance conditions

The restricted shares issued by the Company cannot be transferred during the vesting period, but voting right and dividend right are not restricted. Employees are required to return the shares but not required to return the dividends received if they resign during the vesting period. When the employees accomplish the years of service and performance conditions, the received restricted shares will be vested based on the vesting ratio.

As of December 31, 2019, there were no outstanding restricted shares.

The expenses incurred on share-based payment transactions for the year ended December 31, 2019 was NT$822 thousand.

Capital stock

12 Months Ended

Dec. 31, 2021

Capital stock

21.	Capital stock

As of December 31, 2021, the Company’s authorized capital was NT$9,700,000 thousand, consisting of 970,000 thousand ordinary shares, and the

paid-in

capital was NT$7,272,401 thousand with a par value of NT$10 per share, consisting of 727,240 thousand ordinary shares. All proceeds from shares issued have been collected.

As of December 31, 2021, the outstanding ADSs were approximately 4,586,252 units representing 91,725 thousand ordinary shares and each ADS represents 20 ordinary shares of the Company. The major terms and conditions of the ADSs are summarized as follows:

(a)

Voting rights:

ADS holders have no right to directly vote in shareholders’ meetings with respect to the deposited shares. The depository bank shall vote on behalf of ADS holders or provide voting instruction to the designated person of the Company. The depository bank shall vote in the manner as instructed by ADS holders.

(b)

Distribution of dividends:

ADS holders are deemed to have the same rights as holders of ordinary shares with respect to the distribution of dividends.

Movements in the number of the Company’s ordinary shares outstanding are as follows:


	2019			2020		2021
	in thousands			in thousands		in thousands
January 1		727,265			727,240		727,240
Restricted shares – cancelled		(25	)		—		—

December 31		727,240			727,240		727,240

Treasury stock

On March 7, 2019 and August 6, 2019, the Company’s Board of Directors approved the cancellation of treasury stock 25,570 thousand shares amounted to NT$962,503 thousand. As of December 31, 2019, all of the Company’s treasury stocks were cancelled.

Capital surplus

12 Months Ended

Dec. 31, 2021

Capital surplus

22.	Capital surplus

Pursuant to the ROC Company Act, any capital surplus arising from

paid-in

capital in excess of par value on issuance of ordinary shares and donations can be used to cover accumulated deficits or to issue new shares or cash to shareholders in proportion to their share ownership, provided that the Company has no accumulated deficits. Furthermore, the ROC Securities and Exchange Act requires that the amount of capital surplus to be capitalized mentioned above may not exceed 10% of the

paid-in

capital each year. The capital surplus may not be used to cover accumulated deficits unless the legal reserve is insufficient.


	2019
	Share premium			Employee restricted shares			Others		Total
	NT$000			NT$000			NT$000		NT$000
January 1		5,873,743			382,506			7,304		6,263,553
Share-based payments		—			(412	)		—		(412	)
Cancellation of treasury stock		(199,501	)		(12,853	)		—		(212,354	)

December 31		5,674,242			369,241			7,304		6,050,787


	2020
	Share premium		Employee restricted shares			Others		Total
	NT$000		NT$000			NT$000		NT$000
January 1		5,674,242		369,241			7,304		6,050,787
Reclassifications		369,241		(369,241	)		—		—

December 31		6,043,483		—			7,304		6,050,787


	2021
	Share premium		Employee restricted shares		Others		Total
	NT$000		NT$000		NT$000		NT$000
January 1		6,043,483		—		7,304		6,050,787
Changes in associates accounted for using equity method		—		—		4,834		4,834

December 31		6,043,483		—		12,138		6,055,621

Retained earnings

12 Months Ended

Dec. 31, 2021

Disclosure of reserves within equity [abstract]

Retained earnings

23.	Retained earnings

Under the Company’s Articles of Incorporation, the current year’s earnings, if any, shall first be used to pay all taxes and offset prior years’ operating losses and then 10% of the remaining amount shall be set aside as a legal reserve. The Company may then appropriate or reverse a certain amount as special reserve according to the relevant regulations. After the distribution of earnings, the remaining earnings and prior years’ unappropriated retained earnings may be appropriated according to a proposal by the Board of Directors and approved in the shareholders’ meeting.

The Company’s dividend policy is summarized here. As the Company operates in a volatile business environment, the issuance of dividends to be distributed takes into consideration the Company’s financial structure, operating results and future expansion plans. The earnings distribution of the Company may be made by way of cash dividends or stock dividends, provided that cash dividends account for at least 10% of the total dividends distributed. The earnings distribution will be proposed by the Board of Directors and approved at the shareholders’ meeting.

Except for covering accumulated deficits or issuing new shares or cash to shareholders in proportion to their share ownership, the legal reserve may not be used for any other purpose. The use of the legal reserve for the issuance of shares or cash to shareholders in proportion to their share ownership is permitted, provided that the distribution of the reserve is limited to the portion in excess of 25% of the Company’s

paid-in

capital.

In accordance with the regulations, the Company must set aside a special reserve from the debit balance on other equity items at the statements of financial position date before distributing earnings. When the debit balance on other equity items is reversed subsequently, the reversed amount may be included in the distributable earnings.

The appropriations of 2018, 2019 and 2020 earnings were resolved in the shareholders’ meeting held on June 10, 2019, June 9, 2020 and July 12, 2021, respectively. The appropriations and dividends per share are as follows:


	2018				2019				2020
	Amount		Cash distribution per share		Amount		Cash distribution per share		Amount			Cash distribution per share
	Amount		Cash distribution per share		Amount		Cash distribution per share		Amount			Cash distribution per share
	NT$000		NT$		NT$000		NT$		NT$000			NT$
Legal reserve		110,308				258,416				232,611
Special reserve		—				19,802				(19,802	)
Cash dividend		872,718		1.20		1,309,032		1.80		1,599,928			2.20

Other equity interest

12 Months Ended

Dec. 31, 2021

Other equity interest

24.	Other equity interest


	2019
	Financial statements translation differences of foreign operations			Unrealized gain (loss) on valuation of financial assets at fair value through other comprehensive income			Unearned employee awards			Total
	NT$000			NT$000			NT$000			NT$000
January 1		14,516			106,898			(1,701	)		119,713
Currency translation differences
- The Company		(104,198	)		—			—			(104,198	)
Employee restricted shares
- The Company		—			—			1,701			1,701
Evaluation adjustment
- The Company		—			(52,549	)		—			(52,549	)
- Associates		—			5,093			—			5,093
Evaluation adjustment related tax
- The Company		—			7,016			—			7,016
Disposal of investment accounted for using equity method		—			(72	)		—			(72	)

December 31		(89,682	)		66,386			—			(23,296	)


	2020
	Financial statements translation differences of foreign operations			Unrealized gain (loss) on valuation of financial assets at fair value through other comprehensive income			Total
	NT$000			NT$000			NT$000
January 1		(89,682	)		66,386			(23,296	)
Currency translation differences
- The Company		28,352			—			28,352
Evaluation adjustment
- The Company		—			140,199			140,199
- Associates		—			22,925			22,925
Evaluation adjustment related tax
- The Company		—			(34,794	)		(34,794	)

December 31		(61,330	)		194,716			133,386


	2021
	Financial statements translation differences of foreign operations			Unrealized gain (loss) on valuation of financial assets at fair value through other comprehensive income			Total
	NT$000			NT$000			NT$000
January 1		(61,330	)		194,716			133,386
Currency translation differences
- The Company		(24,695	)		—			(24,695	)
Evaluation adjustment
- The Company		—			122,514			122,514
- Associates		—			21,094			21,094
Evaluation adjustment related tax
- The Company		—			(30,459	)		(30,459	)

December 31		(86,025	)		307,865			221,840

Revenue

12 Months Ended

Dec. 31, 2021

Revenue

25.

Revenue


	Year ended December 31,
	2019		2020		2021
	NT$000		NT$000		NT$000
Revenue from contracts with customers		20,337,881		23,011,381		27,400,035

The Group is primarily engaged in the assembly and testing services on high-integration and high-precision integrated circuits, and recognized revenue based on the progress towards completion of performance obligation during the service period. Information on revenue disaggregation is provided in Note 44.

Contract assets and liabilities

The Group has recognized the following contract assets and liabilities in relation to revenue from contracts with customers:


	January 1, 2020		December 31, 2020		December 31, 2021
	NT$000		NT$000		NT$000
Contract assets		377,869		389,016		400,255

Contract liabilities (Advance payments)		1,231		—		—

The information relating to loss allowance for contract assets is provided in Note 43 a).

Revenue recognized for the years ended December 31, 2020 and 2021, amounted to NT$565 thousand and nil, respectively, was related to carried forward contract liabilities for performance obligations not satisfied in prior year.

All of the service contracts are for periods of one year or less. As permitted under IFRS 15, “Revenue from Contracts with Customers”, the transaction price allocated to these unsatisfied contracts is not disclosed.

Other income (expenses), net

12 Months Ended

Dec. 31, 2021

Other income (expenses), net

26.	Other income (expenses), net


	Year ended December 31,
	2019			2020		2021
	NT$000			NT$000		NT$000
Gain on disposal of scrapped materials		43,652			51,077		52,254
Royalty income		12,336			2,962		907
Gain on disposal of items purchased on behalf of others		15,080			30,140		21,945
Gain on disposal of property, plant and equipment, net		20,271			48,070		33,935
Insurance compensation income		10,435			—		—
Impairment loss on property, plant and equipment		(9,938	)		—		(4,843	)
Gains from lease modifications		—			—		891
Others		1,092			3,329		20,498

		92,928			135,578		125,587

Interest income

12 Months Ended

Dec. 31, 2021

Interest income

27.	Interest income


	Year ended December 31,
	2019		2020		2021
	NT$000		NT$000		NT$000
Bank deposits		59,901		25,547		8,772
Financial assets at amortized cost		4,467		2,206		1,187
Other interest income		—		25		21

		64,368		27,778		9,980

Other income

12 Months Ended

Dec. 31, 2021

Other income

28.	Other income


	Year ended December 31,
	2019		2020		2021
	NT$000		NT$000		NT$000
Rental income		9,249		10,260		17,326
Dividend income		585		3,229		4,690
Grant income		925		7,668		12,480

		10,759		21,157		34,496

Other gains and losses

12 Months Ended

Dec. 31, 2021

Other gains and losses

29.	Other gains and losses


	Year ended December 31,
	2019			2020			2021
	NT$000			NT$000			NT$000
Foreign exchange losses, net		(154,993	)		(355,255	)		(89,152	)
Reimbursement of ADSs service charge		4,292			2,101			2,284
Gain on valuation of financial assets at fair value through profit or loss		1,317			24,015			15,262
Compensation income		—			—			1,524
Others		970			5,872			4,253

		(148,414	)		(323,267	)		(65,829	)

Finance costs

12 Months Ended

Dec. 31, 2021

Finance costs

30.	Finance costs


	Year ended December 31,
	2019			2020			2021
	NT$000			NT$000			NT$000
Interest expense
Bank loans		171,840			158,720			116,946
Lease liabilities		14,349			13,442			15,245
Less: Amounts capitalized in qualifying assets		(15,114	)		(9,762	)		(11,193	)

		171,075			162,400			120,998
Finance expense		9,187			9,082			10,186

		180,262			171,482			131,184

Expenses by nature

12 Months Ended

Dec. 31, 2021

Expenses by nature

31.	Expenses by nature


	Year ended December 31,
	2019		2020		2021
	NT$000		NT$000		NT$000
Raw materials and supplies used		3,575,283		4,708,493		5,518,145
Employee benefit expenses		6,075,773		6,010,227		6,757,888
Depreciation expenses		3,731,914		4,175,519		4,634,112
Others		4,590,720		4,686,218		5,053,088

		17,973,690		19,580,457		21,963,233

Employee benefit expenses

12 Months Ended

Dec. 31, 2021

Employee benefit expenses

32.	Employee benefit expenses


	Year ended December 31,
	2019		2020		2021
	NT$000		NT$000		NT$000
Salaries		5,114,790		4,937,591		5,632,219
Directors’ remuneration		26,266		28,229		40,164
Labor and health insurance		422,106		396,796		424,901
Pension		194,173		189,489		200,014
Share-based payments		822		—		—
Other personnel expenses		317,616		458,122		460,590

		6,075,773		6,010,227		6,757,888

In accordance with the Company’s Articles of Incorporation, employees’ compensation is based on the current year’s earnings, which should first be used to cover accumulated deficits, if any, and then 10% of the remaining balance distributed as employees’ compensation, including distributions to certain qualifying employees in affiliate companies, and no more than 0.5% as directors’ remuneration. Subject to the Board of Directors’ approval, employees’ compensation may be made by way of cash or share issuance. Distribution of employees’ compensation and directors’ remuneration shall be presented and reported in the subsequent shareholders’ meeting.

Based on profit distributable as of the end of reporting period, for the years ended December 31, 2019, 2020 and 2021, the employees’ compensation were accrued at NT$338,356 thousand, NT$332,080 thousand and NT$673,387 thousand, respectively; the directors’ remuneration were accrued at NT$16,918 thousand, NT$16,604 thousand and NT$25,690 thousand, respectively.

For the year of 2020, employees’ compensation and directors’ remuneration recognized were consistent with the amounts resolved in the Board of Directors’ meeting.

Income tax expense

12 Months Ended

Dec. 31, 2021

Income tax expense

33.	Income tax expense

Income tax expense

(a)

Components of income tax expense:


	Year ended December 31,
	2019			2020			2021
	NT$000			NT$000			NT$000
Current income tax:
Current income tax on profits for the period		408,788			636,876			1,109,752
Income tax on unappropriated retained earnings		74,540			105,665			227,467
Prior year income tax overestimation		(5,016	)		(133,923	)		(184,284	)

Total current income tax		478,312			608,618			1,152,935

Deferred income tax:
Relating to origination and reversal of temporary differences		35,367			(14,237	)		(54,617	)

Income tax expense		513,679			594,381			1,098,318

(b)

The income tax (charge)/credit relating to components of other comprehensive income are as follows:


	Year ended December 31,
	2019			2020			2021
	NT$000			NT$000			NT$000
Unrealized (loss) gain on valuation of financial assets at fair value through other comprehensive income		(7,016	)		34,794			30,459
Remeasurement of defined benefit obligations		4,183			(10,398	)		(2,999	)

		(2,833	)		24,396			27,460

Reconciliation of income tax expense and the accounting profit:


	Year ended December 31,
	2019			2020			2021
	NT$000			NT$000			NT$000
Tax calculated based on profit before tax and statutory tax rate		606,917			595,258			1,207,605
Effects from adjustments based on regulation		(162,924	)		26,974			(152,618	)
Temporary difference not recognized as deferred tax assets		(608	)		(4	)		—
Prior year income tax overestimation		(5,016	)		(133,923	)		(184,284	)
Income tax on unappropriated retained earnings		74,540			105,665			227,467
Effect of different tax rates in countries in which the Group operates		770			411			148

Income tax expense		513,679			594,381			1,098,318

The amounts of deferred tax assets or liabilities resulting from temporary differences and investment tax credits are as follows:


	2019
	January 1			Recognized in profit or loss			Recognized in other comprehensive income			December 31
	NT$000			NT$000			NT$000			NT$000
Deferred tax assets
Loss on inventories		7,232			5,468			—			12,700
Property, plant and equipment		64,183			(25,515	)		—			38,668
Provisions		12,396			(6,796	)		—			5,600
Deferred revenue		34,156			(6,506	)		—			27,650
Net defined benefit liability		100,743			(3,948	)		(4,183	)		92,612
Unrealized exchange losses		3,575			13,721			—			17,296
Investment tax credit		4,420			(4,420	)		—			—
Others		11			15			—			26

Total		226,716			(27,981	)		(4,183	)		194,552

Deferred tax liabilities
Property, plant and equipment		(281,594	)		(7,386	)		—			(288,980	)
Financial assets at fair value through other comprehensive income		(27,165	)		—			7,016			(20,149	)

Total		(308,759	)		(7,386	)		7,016			(309,129	)

Information presented on statements of financial position
Deferred tax assets		226,716									194,552

Deferred tax liabilities		(308,759	)								(309,129	)


	2020
	January 1			Recognized in profit or loss			Recognized in other comprehensive income			December 31
	NT$000			NT$000			NT$000			NT$000
Deferred tax assets
Loss on inventories		12,700			3,263			—			15,963
Property, plant and equipment		38,668			(2,267	)		—			36,401
Provisions		5,600			(2,922	)		—			2,678
Deferred revenue		27,650			(6,506	)		—			21,144
Net defined benefit liability		92,612			(4,089	)		10,398			98,921
Unrealized exchange losses		17,296			(7,381	)		—			9,915
Others		26			643			—			669

Total		194,552			(19,259	)		10,398			185,691

Deferred tax liabilities
Property, plant and equipment		(288,980	)		33,496			—			(255,484	)
Financial assets at fair value through other comprehensive income		(20,149	)		—			(34,794	)		(54,943	)

Total		(309,129	)		33,496			(34,794	)		(310,427	)

Information presented on statements of financial position
Deferred tax assets		194,552									185,691

Deferred tax liabilities		(309,129	)								(310,427	)


	2021
	January 1			Recognized in profit or loss			Recognized in other comprehensive income			December 31
	NT$000			NT$000			NT$000			NT$000
Deferred tax assets
Loss on inventories		15,963			8,354			—			24,317
Property, plant and equipment		36,401			235			—			36,636
Provisions		2,678			171			—			2,849
Deferred revenue		21,144			(6,506	)		—			14,638
Net defined benefit liability		98,921			(4,672	)		2,999			97,248
Unrealized exchange losses		9,915			(7,754	)		—			2,161
Others		669			2,080			—			2,749

Total		185,691			(8,092	)		2,999			180,598

Deferred tax liabilities
Property, plant and equipment		(255,484	)		62,797			—			(192,687	)
Financial assets at fair value through other comprehensive income		(54,943	)		—			(30,459	)		(85,402	)
Others		—			(88	)		—			(88	)

Total		(310,427	)		62,709			(30,459	)		(278,177	)

Information presented on statements of financial position
Deferred tax assets		185,691									180,598

Deferred tax liabilities		(310,427	)								(278,177	)

The amounts of deductible temporary difference that are not recognized as deferred tax assets are as follows:


	December 31, 2020		December 31, 2021
	NT$000		NT$000
Deductible temporary differences		946,236		371,133

The Company has not recognized taxable temporary differences associated with investments as deferred tax liabilities. As of December 31, 2020 and 2021, the amounts of temporary differences not recognized as deferred tax liability were NT$45,005 thousand and NT$609,709 thousand, respectively.

The Company’s income tax returns through 2019 have been assessed and approved by the Tax Authority.

On October 31, 2016, the Company merged with its former parent company, ChipMOS TECHNOLOGIES (Bermuda) LTD. And as a result, the Company recognized its own shares originally held by former parent company as treasury stock. Subsequently, the Company deducted unappropriated retained earnings by NT$5,052,343 thousand to reflect the loss due from the cancellation of treasury stock. In January 2017, the Company has filed an application to the National Taxation Bureau of the Northern Area, Ministry of Finance to apply the accumulated deficit amount, as a deduction in the calculation of years 2015 and 2016 additional 10% tax on unappropriated retained earnings. In April and June 2020, the Company received the Notice for Assessment of Tax for the years 2015 and 2016 from the National Taxation Bureau of the Northern Area, Ministry of Finance, and the tax refund amounted to NT$138,941 thousand was received in year 2020.

Earnings per share

12 Months Ended

Dec. 31, 2021

Earnings per share

34.	Earnings per share

Year ended December 31, 2019

Amount

after income
tax

Weighted average
number of ordinary
shares outstanding

Earnings

per share

Basic earnings per share

NT$000

In thousands

NT$

Profit attributable to equity holders of the Company

2,508,574

727,111

3.45

Diluted earnings per share

Assumed conversion of all dilutive potential ordinary shares:

Employees’ compensation

9,879

Restricted shares

126

Profit attributable to equity holders of the Company

2,508,574

737,116

3.40

Year ended December 31, 2020

Amount

after income
tax

Weighted average
number of ordinary
shares outstanding

Earnings

per share

Basic earnings per share

NT$000

In thousands

NT$

Profit attributable to equity holders of the Company

2,378,978

727,240

3.27

Diluted earnings per share

Assumed conversion of all dilutive potential ordinary shares:

Employees’ compensation

9,668

Profit attributable to equity holders of the Company

2,378,978

736,908

3.23

Year ended December 31, 2021

Amount

after income
tax

Weighted average
number of ordinary
shares outstanding

Earnings

per share

Basic earnings per share

NT$000

In thousands

NT$

Profit attributable to equity holders of the Company

4,937,267

727,240

6.79

Diluted earnings per share

Assumed conversion of all dilutive potential ordinary shares:

Employees’ compensation

15,618

Profit attributable to equity holders of the Company

4,937,267

742,858

6.65

Supplementary cash flow information

12 Months Ended

Dec. 31, 2021

Supplementary cash flow information

35.	Supplementary cash flow information

Partial cash paid for investing activities

Property, plant and equipment


	Year ended December 31,
	2019			2020			2021
	NT$000			NT$000			NT$000
Purchase of property, plant and equipment		4,896,656			4,133,615			6,552,702
Add: Beginning balance of payable to contractors and equipment suppliers		1,516,735			972,770			1,145,359
Less: Ending balance of payable to contractors and equipment suppliers		(972,770	)		(1,145,359	)		(1,816,555	)

Cash paid during the year		5,440,621			3,961,026			5,881,506

Changes in liabilities from financing activities

12 Months Ended

Dec. 31, 2021

Changes in liabilities from financing activities

36.	Changes in liabilities from financing activities


	2019
	Long-term bank loans (including current portion)			Guarantee deposits		Lease liabilities			Total liabilities from financing activities
	NT$000			NT$000		NT$000			NT$000
January 1		9,789,518			1,092		—			9,790,610
Effects on initial application of IFRS 16		—			—		884,275			884,275

Adjusted balance at January 1		9,789,518			1,092		884,275			10,674,885
Changes in cash flow from financing activities		(756,450	)		3		(48,161	)		(804,608	)
Adjustment to right-of-use assets		—			—		(148,512	)		(148,512	)
Reclassification to payable on equipment from lease liabilities		—			—		(9,000	)		(9,000	)
Amortization of loan fees		8,577			—		—			8,577
Amortization of interest expense		—			—		14,349			14,349

December 31		9,041,645			1,095		692,951			9,735,691


	2020
	Long-term bank loans (including current portion)			Guarantee deposits		Lease liabilities			Total liabilities from financing activities
	NT$000			NT$000		NT$000			NT$000
January 1		9,041,645			1,095		692,951			9,735,691
Changes in cash flow from financing activities		(1,326,857	)		575		(84,928	)		(1,411,210	)
Adjustment to right-of-use assets		—			—		249,030			249,030
Reclassification		—			20,000		—			20,000
Amortization of loan fees		7,581			—		—			7,581
Amortization of interest expense		11,196			—		13,442			24,638

December 31		7,733,565			21,670		870,495			8,625,730


	2021
	Short-term bank loans		Long-term bank loans (including current portion)		Guarantee deposits			Lease liabilities			Total liabilities from financing activities
	NT$000		NT$000		NT$000			NT$000			NT$000
January 1		—		7,733,565		21,670			870,495			8,625,730
Changes in cash flow from financing activities		731,751		1,652,332		(45	)		(289,668	)		2,094,370
Adjustment to right-of-use assets		—		—		—			255,179			255,179
Amortization of loan fees		—		7,646		—			—			7,646
Amortization of interest expense		—		19,822		—			15,245			35,067

December 31		731,751		9,413,365		21,625			851,251			11,017,992

Related party transactions

12 Months Ended

Dec. 31, 2021

Related party transactions

37.	Related party transactions

Parent and ultimate controlling party

The Company has neither a parent company nor an ultimate controlling party. The transactions between the Company and its subsidiaries were eliminated in the accompanying consolidated financial statements and were not disclosed herein. The transactions between the Group and other related parties are as follows.

Names of related parties and relationship


Name	Relationship
Unimos Shanghai		Associate
JMC		Associate

Significant related party transactions

None.

Key management personnel compensation


	Year ended December 31,
	2019		2020		2021
	NT$000		NT$000		NT$000
Salaries and other short-term employee benefits		178,713		186,854		243,405
Post-employment compensation		2,049		4,258		2,156

		180,762		191,112		245,561

Pledged assets

12 Months Ended

Dec. 31, 2021

Pledged assets

38.	Pledged assets

Assets

Purpose

December 31,
2020

December 31,
2021

Carrying
amount

NT$000

Non-current

financial assets at amortized cost

Lease and bank loan

48,319

37,539

Property, plant and equipment, net

- Land

Bank loan

452,738

- Buildings

Bank loan

4,092,287

4,343,556

- Machinery and equipment

Bank loan

6,912,544

8,245,561

11,505,888

13,079,394

Significant contingent liabilities and unrecognized contract commitments

12 Months Ended

Dec. 31, 2021

Significant contingent liabilities and unrecognized contract commitments

39.	Significant contingent liabilities and unrecognized contract commitments

A letter of guarantee was issued by the financial institutions to the Customs Administration of the Ministry of Finance for making payment of customs-duty deposits when importing. As of December 31, 2020 and 2021, the amounts guaranteed by the financial institutions were NT$99,000 thousand and NT$137,700 thousand, respectively.

Capital expenditures that are contracted for, but not provided for are as follows:


	December 31, 2020		December 31, 2021
	NT$000		NT$000
Property, plant and equipment, net		2,331,041		2,629,129

Significant disaster loss

12 Months Ended

Dec. 31, 2021

Significant disaster loss

40.	Significant disaster loss

None.

Significant events after the reporting periods

12 Months Ended

Dec. 31, 2021

Significant events after the reporting periods

41.	Significant events after the reporting period

None.

Capital management

12 Months Ended

Dec. 31, 2021

Capital management

42.	Capital management

The Group’s objectives when managing capital are to safeguard the Group’s ability to continue as a going concern in order to provide returns for shareholders and to maintain an optimal capital structure to reduce the cost of capital. In order to maintain or adjust the capital structure, the Group may adjust the amount of dividends paid to shareholders, return capital to shareholders, issue new shares or sell assets to reduce debt. The Group monitors capital on the basis of the liabilities to assets ratio. Total capital is shown as “Equity” in the consolidated statements of financial position, which is also equal to total assets minus total liabilities.

The liabilities to assets ratio at December 31, 2020 and 2021 were as follows:


	December 31, 2020			December 31, 2021
	NT$000			NT$000
Total liabilities		14,364,975			18,380,369
Total assets		35,080,814			42,522,584

Liabilities to assets ratio		40.95	%		43.22	%

Financial risk management and fair values of financial instruments

12 Months Ended

Dec. 31, 2021

Financial risk management and fair values of financial instruments

43.	Financial risk management and fair values of financial instruments

Financial instruments

(a)

Financial instruments by category


	December 31, 2020		December 31, 2021
	NT$000		NT$000
Financial assets
Financial assets at fair value through profit or loss
Financial assets mandatorily measured at fair value through profit or loss		63,488		359,960
Financial assets at fair value through other comprehensive income
Designation of equity instruments		262,007		384,521
Financial assets at amortized cost
Cash and cash equivalents		4,113,651		5,906,176
Financial assets at amortized cost		254,801		66,778
Notes receivable		599		1,035
Accounts receivable		5,364,156		6,344,246
Other receivables		51,436		86,879
Refundable deposits		21,186		21,278

		10,131,324		13,170,873

Financial liabilities
Financial liabilities at amortized cost
Short-term bank loans		—		731,751
Notes payable		2,899		23
Accounts payable		966,821		1,012,391
Other payables		3,249,403		4,378,439
Long-term bank loans (including current portion)		7,733,565		9,413,365
Lease liabilities (including current portion)		870,495		851,251
Guarantee deposits		21,670		21,625

		12,844,853		16,408,845

(b)

Risk management policies

The Group’s risk management objective is to manage the market risk, credit risk and liquidity risk related to its operating activities. The Group identifies, measures, and manages such risks by its policies and preferences.

ii)

The Group has established appropriate policies, procedures and internal controls for financial risk management. Before entering into significant financial transactions, a due approval process must be carried out by the Board of Directors based on related protocols and internal control procedures. The Group complies with its financial risk management policies at all times.

iii)

In order to minimize and manage financial risks, the Group’s overall risk management program focuses on analyzing, identifying, and evaluating financial risk factors that may potentially have adverse effects on the Group’s financial position, and provide feasible solutions to avoid those factors.

(c)

Significant financial risks and degrees of financial risks

Market risk

The Group’s market risk is the risk that the fair value or future cash flows of a financial instrument will fluctuate because of changes in market prices. Market risks comprise foreign currency risk, interest rate risk, and other price risks.

In practice, the risk variable rarely changes individually, and the change of each risk variable is usually correlative. The following sensitivity analysis did not consider the interaction of each risk variable.

Foreign exchange risk

The Group’s exposure to the risk of changes in foreign exchange rates relates primarily to the Group’s operating activities (when revenue or expense is denominated in a different currency from the Company’s and its subsidiaries’ functional currency) and the Group’s net investments in foreign operations.

The Group applies natural hedges by using accounts receivable and accounts payable denominated in the same currency. However, this natural hedge does not concur with the requirement for hedge accounting. Furthermore, as net investments in foreign operations are for strategic purposes, they are not hedged by the Group.

The Group’s foreign currency exposure gives rise to market risks associated with exchange rate movements against the NT dollar for cash and cash equivalents, accounts receivable, other receivables, bank loans, accounts payable and other payables.

The Group’s businesses involve some

non-functional

currency operations. The information on assets and liabilities denominated in foreign currencies whose values would be materially affected by the exchange rate fluctuations is as follows:


	December 31, 2020
	Foreign currency		Exchange rate		Carrying amount (NT$000)
(Foreign currency: functional currency)
Financial assets
Monetary items
US$000		175,840		28.4800		5,007,923
JPY000		137,635		0.2763		38,029
RMB000		6,838		4.3770		29,930
Non-monetary items
JPY000		948,270		0.2763		262,007
RMB000		690,178		4.3770		3,020,908
Financial liabilities
Monetary items
US$000		26,410		28.4800		752,157
JPY000		1,538,241		0.2763		425,016


	December 31, 2021
	Foreign currency		Exchange rate		Carrying amount (NT$000)
(Foreign currency: functional currency)
Financial assets
Monetary items
US$000		188,143		27.6800		5,207,798
JPY000		141,523		0.2405		34,036
RMB000		4,944		4.3440		21,477
Non-monetary items
JPY000		1,598,839		0.2405		384,521
RMB000		827,811		4.3440		3,596,012
Financial liabilities
Monetary items
US$000		53,042		27.6800		1,468,203
JPY000		1,089,668		0.2405		262,005

The total exchange losses, including realized and unrealized losses arising from significant foreign exchange variations on monetary items held by the Group for the years ended December 31, 2019, 2020 and 2021, amounted to NT$154,993 thousand, NT$355,255 thousand and NT$89,152 thousand, respectively.

Analysis of foreign currency market risk arising from significant foreign exchange variations:


	Year ended December 31, 2019
	Sensitivity analysis
	Change in exchange rate			Effect on profit (loss) (NT$000)		Effect on other comprehensive income (NT$000)
Financial assets
Monetary items
US$000		5	%		282,365		—
JPY000		5	%		3,682		—
RMB000		5	%		1,334		—
Financial liabilities
Monetary items
US$000		5	%		11,793		—
JPY000		5	%		14,261		—


	Year ended December 31, 2020
	Sensitivity analysis
	Change in exchange rate			Effect on profit (loss) (NT$000)		Effect on other comprehensive income (NT$000)
Financial assets
Monetary items
US$000		5	%		250,396		—
JPY000		5	%		1,901		—
RMB000		5	%		1,497		—
Financial liabilities
Monetary items
US$000		5	%		37,608		—
JPY000		5	%		21,251		—


	Year ended December 31, 2021
	Sensitivity analysis
	Change in exchange rate			Effect on profit (loss) (NT$000)		Effect on other comprehensive income (NT$000)
Financial assets
Monetary items
US$000		5	%		260,390		—
JPY000		5	%		1,702		—
RMB000		5	%		1,074		—
Financial liabilities
Monetary items
US$000		5	%		73,410		—
JPY000		5	%		13,103		—

Price risk

The Group’s financial instruments, which are exposed to price risk, are the financial assets at fair value through profit or loss and financial assets at fair value through other comprehensive income. To manage its price risk arising from investments in financial instruments, the Group diversifies its portfolio. Diversification of the portfolio is in accordance with the limits set by the Group.

The Group invests in beneficiary certificates and listed stocks issued by the domestic companies. The prices of equity securities would change due to change of the future value of investee companies. For the years ended December 31, 2019, 2020 and 2021, it is estimated that the prices of equity securities increase or decrease by 1%, with all other variables held constant, would increase or decrease the Group’s profit before income tax by nil, NT$531 thousand and NT$3,600 thousand, respectively.

The Group’s investments in financial instruments comprise foreign unlisted stocks and partnership. The prices of financial instruments would change due to different valuation models and assumptions used. Analysis related to the effect on profit or other comprehensive income if these assumptions change is provided in Note 43 b) (g).

Interest rate risk on cash flow and fair value

Interest rate risk is the risk that the fair value or future cash flows of a financial instrument will fluctuate because of changes in market interest rates. The Group’s exposure to the risk of changes in market interest rates relates primarily to the Group’s bank loans with floating interest rates. The Group manages its interest rate risk by having a balanced portfolio of fixed and variable rate bank loans. The Group reassesses the hedge management periodically to make sure it complies with the cost effectiveness.

The sensitivity analysis depends on the exposure of interest rate risk at the end of the reporting period.

Analysis of debt with floating interest rates is based on the assumption that the outstanding debt at the end of the reporting period is outstanding throughout the period. The degree of variation the Group used to report to internal management is increase or decrease of 1% in interest rates which is assessed as the reasonable degree of variation by the management.

For the years ended December 31, 2019, 2020 and 2021, it is estimated that a general increase or decrease of 1% in interest rates, with all other variables held constant, would decrease or increase the Group’s profit before income tax approximately by NT$90,660 thousand, NT$78,150 thousand and NT$102,489 thousand, respectively, mainly due to the Group’s floating rate on bank loans.

ii)

Credit risk

Credit risk is the risk that a counterparty will not meet its obligations under a financial instrument or customer contract, leading to a financial loss, mainly resulted from its operating activities (primarily notes and accounts receivable) and from its financing activities (primarily deposits with banks and financial instruments). The Group is exposed to credit risk arising from the carrying amount of the financial assets recognized in the consolidated statements of financial position.

Each business unit performs ongoing credit evaluations of its debtors’ financial conditions according to the Group’s established policies, procedures and controls relating to customer credit risk management. The Group maintains an account for loss allowance based upon the available facts and circumstances, history of collection and

write-off

experiences of all trade and other receivables which consequently minimize the Group’s exposure to bad debts.

Credit risk from balances with banks and financial institutions is managed by the Group’s finance unit in accordance with the Group’s policies. Transaction counterparty of the Group is determined through its internal controls policy. For banks and financial institutions, only parties rated above BBB+ by Taiwan Ratings are accepted. The probability of counterparty default is remote, so there is no significant credit risk.

The Group adopts the assumptions under IFRS 9 “Financial Instruments” and the default is deemed to have occurred when the contract payments are past due over 90 days.

The Group categorized contract assets, accounts receivable and other receivables by characteristics of credit risk and applied the simplified approach using loss rate methodology to estimate expected credit loss.

The Group referred to the forecastability of business monitoring indicators published by the ROC National Development Council to adjust the loss rate which is based on historical and current information when assessing the future default possibility of contract assets, accounts receivable and other receivables. As of December 31, 2020 and 2021 the loss rate methodologies are as follows:


	December 31, 2020
	Contract assets			Accounts receivable (including related parties)			Other receivables (including related parties)
	NT$000			NT$000			NT$000
Expected loss rate		0.030	%		0.030	%		0.030	%
Total carrying amount		389,133			5,365,776			51,446
Loss allowance		(117	)		(1,620	)		(10	)


	December 31, 2021
	Contract assets			Accounts receivable (including related parties)			Other receivables (including related parties)
	NT$000			NT$000			NT$000
Expected loss rate		0.030	%		0.030	%		0.030	%
Total carrying amount		400,375			6,346,156			86,895
Loss allowance		(120	)		(1,910	)		(16	)

Under the simplified approach, movements in relation to loss allowance for contract assets, accounts receivable, and other receivables are as follows:


	2019
	Contract assets			Accounts receivable (including related parties)			Other receivables (including related parties)
	NT$000			NT$000			NT$000
January 1		(135	)		(2,141	)		(13	)
Provision for impairment loss		—			—			(5	)
Reversal of impairment loss		21			790			—

December 31		(114	)		(1,351	)		(18	)


	2020
	Contract assets			Accounts receivable (including related parties)			Other receivables (including related parties)
	NT$000			NT$000			NT$000
January 1		(114	)		(1,351	)		(18	)
Provision for impairment loss		(3	)		(269	)		—
Reversal of impairment loss		—			—			8

December 31		(117	)		(1,620	)		(10	)


	2021
	Contract assets			Accounts receivable (including related parties)			Other receivables (including related parties)
	NT$000			NT$000			NT$000
January 1		(117	)		(1,620	)		(10	)
Provision for impairment loss		(3	)		(290	)		(6	)

December 31		(120	)		(1,910	)		(16	)

The Group’s recorded financial assets at amortized cost include time deposits with contract period over three months and restricted bank deposits. Because of the low credit risk, expected credit losses for the period are measured through a loss allowance at an amount equal to the

12-month

expected credit losses. There is no significant provision for the losses.

iii)

Liquidity risk

The Group manages and maintains adequate cash and cash equivalents to finance the Group’s operations, and minimize the impact from cash flow fluctuations. The Group also monitors its debt financing plans to ensure it is in compliance with the financial covenants required under its loan agreements.

The primary source of liquidity for the Group is from bank loans. See Notes 15 and 18 for details of the unused credit lines of the Group as of December 31, 2020 and 2021.

The contractual undiscounted cash flows of notes payable, accounts payable and other payables due within one year and is equivalent to its carrying amount. Except for the aforementioned, the table below summarizes the maturity profile of the Group’s

non-derivative

financial liabilities based on the earliest repayment dates and contractual undiscounted payments, including principal and interest. The Group does not consider the probability of early repayments requested by the banks.


	December 31, 2020
	Within 1 year		1 to 3 years		3 to 5 years		Over 5 years		Total
	NT$000		NT$000		NT$000		NT$000		NT$000
Non-derivative financial liabilities
Long-term bank loans		846,401		3,558,597		2,198,717		1,487,808		8,091,523
Lease liabilities		145,594		160,146		54,689		718,752		1,079,181
Guarantee deposits		—		—		—		21,670		21,670

		991,995		3,718,743		2,253,406		2,228,230		9,192,374


	December 31, 2021
	Within 1 year		1 to 3 years		3 to 5 years		Over 5 years		Total
	NT$000		NT$000		NT$000		NT$000		NT$000
Non-derivative financial liabilities
Short-term bank loans		733,523		—		—		—		733,523
Long-term bank loans		114,953		2,817,662		4,568,521		2,265,350		9,766,486
Lease liabilities		182,186		119,748		54,113		691,764		1,047,811
Guarantee deposits		—		—		—		21,625		21,625

		1,030,662		2,937,410		4,622,634		2,978,739		11,569,445

The difference between the floating interest rates and estimated interest rates will affect the

non-derivative

financial liabilities stated above.

Fair value information

(a)

The different levels of inputs used in valuation techniques to measure fair value of financial and

non-financial

instruments are defined as follows:


Level 1:		Quoted prices (unadjusted) in active markets for identical assets or liabilities that can be accessed at the measurement date. An active market is a market in which trading for the asset or liability take place with sufficient frequency and volume to provide pricing information on an ongoing basis.

Level 2:		Inputs other than quoted prices from Level 1 that are observable information for the asset or liability, either directly or indirectly.

Level 3:		Unobservable inputs for the asset or liability. The fair value of the Group’s investment in equity investment without active market is included in Level 3.

(b)

The carrying amounts of cash and cash equivalents, financial assets at amortized cost, contract assets, notes receivable, accounts receivable, other receivables, refundable deposits, bank loans, notes payable, accounts payable, other payables, lease liabilities and guarantee deposits are approximate to their fair values.

(c)

The related information of financial and

non-financial

instruments measured at fair value by level based on the nature, characteristics and risks of the assets and liabilities are as follows:

The related information of natures of the assets and liabilities are as follows:


	December 31, 2020
	Level 1		Level 2		Level 3		Total
	NT$000		NT$000		NT$000		NT$000
Assets
Recurring fair value measurements
Financial assets at fair value through profit or loss
- Listed stocks		53,120		—		—		53,120
- Foreign partnership interests		—		—		10,368		10,368
Financial assets at fair value through other comprehensive income
- Foreign unlisted stocks		—		—		262,007		262,007

		53,120		—		272,375		325,495


	December 31, 2021
	Level 1		Level 2		Level 3		Total
	NT$000		NT$000		NT$000		NT$000
Assets
Recurring fair value measurements
Financial assets at fair value through profit or loss
- Listed stocks		359,960		—		—		359,960
Financial assets at fair value through other comprehensive income
- Foreign unlisted stocks		—		—		384,521		384,521

		359,960		—		384,521		744,481

ii)

The methods and assumptions the Group used to measure fair value are as follows:

The fair value of the Group’s listed stocks is measured by using the market quoted prices, which is categorized within Level 1 fair value.

Except for listed stocks with active markets, the fair value of the Group’s other financial instruments is measured by using valuation techniques or by reference to counterparty quotes. The fair value of financial instruments measured by using valuation techniques can be referred to current fair value of instruments with similar terms and characteristics in substance, discounted cash flow method or other valuation methods, including calculated by applying model using market information available at the consolidated statement of financial position date.

The Group’s financial instruments issued by foreign partnerships are measured by using the discounted cash flow method, which derives present value estimates by discounting expected future operating effectiveness and free cash flows projections.

The Group’s financial instruments issued by foreign companies are measured by the comparable company valuation (EV/EBITDA ratio and P/B ratio).

The Group takes into account adjustments for credit risks to measure the fair value of financial and

non-financial

instruments to reflect credit risk of the counterparty and the Group’s credit quality.

(d)

The following table shows the movements of Level 3 for the years ended December 31, 2020 and 2021:


	December 31, 2020
	Debt instruments			Equity instruments		Total
	NT$000			NT$000		NT$000
January 1		11,038			121,808		132,846
Gains or losses recognized in profit or loss
Recorded as non-operating expenses		(670	)		—		(670	)
Gains or losses recognized in other comprehensive income
Recorded as unrealized gains on valuation of financial assets at fair value through other comprehensive income		—			140,199		140,199

December 31		10,368			262,007		272,375


	December 31, 2021
	Debt instruments			Equity instruments		Total
	NT$000			NT$000		NT$000
January 1		10,368			262,007		272,375
Gains or losses recognized in profit or loss
Recorded as non-operating expenses		(941	)		—		(941	)
Gains or losses recognized in other comprehensive income
Recorded as unrealized gains on valuation of financial assets at fair value through other comprehensive income		—			122,514		122,514
Sold in the period		(9,427	)		—		(9,427	)

December 31		—			384,521		384,521

(e)

The Group performs the fair value measurements being categorized within Level 3 with assistance from specialist. Such assessment is to ensure the valuation results are reasonable by applying independent information to make results close to current market conditions, confirming the resource of information is independent, reliable and in line with other resources and represented as the exercisable price, and frequently calibrating valuation model, updating inputs used to the valuation model and making any other necessary adjustments to the fair value.

(f)

The following is the qualitative information and sensitivity analysis of changes in significant unobservable inputs under valuation model used in Level 3 fair value measurement:

Fair value as of

December 31,
2020

Valuation

technique

Significant

unobservable
input

Range

(weighted
average
method)

Relationship of inputs

to fair value

NT$000

Non-derivative

debt instrument:

Foreign partnership interests

10,368

Discounted cash flow

Discount
rate

0.30

The lower the discount rate, the higher the fair value

Non-derivative

equity instrument:

Foreign unlisted stocks

262,007

Comparable companies

Price to book
ratio
multiple

1.97

The higher the multiple, the higher the fair value

Enterprise
value to
EBITDA
multiple

12.00

The higher the multiple, the higher the fair value

Discount for
lack of
marketability

15.80

The higher the discount for lack of marketability, the lower the fair value

Fair value as of

December 31,
2021

Valuation

technique

Significant

unobservable
input

Range

(weighted

average
method)

Relationship of inputs

to fair value

NT$000

Non-derivative

equity instrument:

Foreign unlisted stocks

384,521

Comparable companies

Price to book
ratio
multiple

3.46

The higher the multiple, the higher the fair value

Enterprise
value to
EBITDA
multiple

9.43

The higher the multiple, the higher the fair value

Discount for
lack of
marketability

15.80

The higher the discount for lack of marketability, the lower the fair value

(g)

The Group has carefully assessed the valuation models and assumptions used to measure fair value. However, use of different valuation models or assumptions may result in different measurement. The following is the effect of profit or loss or of other comprehensive income from financial assets categorized within Level 3 if the inputs used to valuation models have changed:


			December 31, 2020
			Recognized in profit or loss				Recognized in other comprehensive income
	Input	Change	Favorable change		Unfavorable change		Favorable change		Unfavorable change
			NT$000		NT$000		NT$000		NT$000
Financial assets:
Foreign partnership interests	Discount rate	Note		—		—		—		—
Foreign unlisted stocks	Price to book ratio multiple	± 1%		—		—		30		30
	Enterprise value to EBITDA multiple	± 1%		—		—		2,153		2,153
	Discount for lack of marketability	± 1%		—		—		3,142		3,084

				—		—		5,325		5,267

Note:

Based on the Group’s assessment, change in input would not have significant impact on profit or loss or other comprehensive income.


					December 31, 2021
					Recognized in profit or loss				Recognized in other comprehensive income
	Input		Change		Favorable change		Unfavorable change		Favorable change		Unfavorable change
					NT$000		NT$000		NT$000		NT$000
Financial assets:
Foreign unlisted stocks		Price to book ratio multiple		±1%		—		—		46		46
		Enterprise value to EBITDA multiple		±1%		—		—		3,443		3,443
		Discount for lack of marketability		±1%		—		—		4,585		4,585

						—		—		8,074		8,074

Other matter

In response to the

COVID-19

pandemic, besides complying with the reporting guidelines and prevention management measures issued by the Taiwan Centers for Disease Control, the Group has also drawn up an epidemic preparedness and contingency plan and set up a response team, taking appropriate actions on pandemic protections as well as establishing epidemic prevention and response mechanism based on the pandemic situation to ensure employees’ health and the normal operation of production lines. Meanwhile, the Group maintains sufficient stock of main raw materials required for production. To reduce the risk of raw materials disruption, the Group takes the proper preventive plan based on the pandemic situation in the suppliers’ region, including increase safety stock or establish a second supply source. In summary, the Group has proactively adopted corresponding measures and continued to manage relevant matters. Based on the Group’s assessment, the

COVID-19

pandemic has no significant impact on the Group.

Segment Information

12 Months Ended

Dec. 31, 2021

Segment Information

44.	Segment Information

General information

The Group engages mainly in the assembly and testing of semiconductors, memory modules and general investments. In accordance with IFRS 8 “Operating Segments”, the Group’s segments include Testing, Assembly, Testing and Assembly for LCD, OLED and other Display Panel Driver Semiconductors (“LCDD”), Bumping and others as the five reportable segments.

Measurement of segment information

The Group’s reportable segments are strategic business units which provide different products and services. The accounting policies adopted by the operating segments are the same as the accounting policies described in Note 4.

Information about segment profit or loss

The segment information provided to the chief operating decision maker for the reportable segments is as follows:


	Year ended December 31, 2019
	Testing			Assembly			LCDD			Bumping			Others			Elimination			Total
	NT$000			NT$000			NT$000			NT$000			NT$000			NT$000			NT$000
Revenue
External customers		4,257,800			5,148,877			6,922,205			4,008,999			—			—			20,337,881
Inter-segment		—			—			—			—			32,808			(32,808	)		—

Total revenue		4,257,800			5,148,877			6,922,205			4,008,999			32,808			(32,808	)		20,337,881

Operating profit (loss)		709,142			(227,096	)		1,740,720			232,404			1,931			18			2,457,119

Depreciation expenses		(802,740	)		(521,311	)		(1,796,951	)		(604,553	)		(6,359	)		—			(3,731,914	)

Share of profit (loss) of associates		—			—			—			—			(370,351	)		215,425			(154,926	)

Interest income		—			—			—			—			64,368			—			64,368

Interest expense		—			—			—			—			(171,075	)		—			(171,075	)

Purchase of property, plant and equipment		764,105			548,063			3,077,806			506,635			47			—			4,896,656


	Year ended December 31, 2020
	Testing			Assembly			LCDD			Bumping			Others			Elimination			Total
	NT$000			NT$000			NT$000			NT$000			NT$000			NT$000			NT$000
Revenue
External customers		5,002,730			6,001,964			7,023,003			4,983,684			—			—			23,011,381
Inter-segment		—			—			—			—			39,646			(39,646	)		—

Total revenue		5,002,730			6,001,964			7,023,003			4,983,684			39,646			(39,646	)		23,011,381

Operating profit (loss)		1,333,682			67,730			1,687,986			487,323			(10,230	)		11			3,566,502

Depreciation expenses		(853,829	)		(523,341	)		(2,213,504	)		(578,890	)		(5,955	)		—			(4,175,519	)

Share of profit (loss) of associates		—			—			—			—			(320,578	)		173,249			(147,329	)

Interest income		—			—			—			—			27,778			—			27,778

Interest expense		—			—			—			—			(162,400	)		—			(162,400	)

Purchase of property, plant and equipment		887,204			803,693			2,143,401			298,834			483			—			4,133,615


	Year ended December 31, 2021
	Testing			Assembly			LCDD			Bumping			Others			Elimination			Total
	NT$000			NT$000			NT$000			NT$000			NT$000			NT$000			NT$000
Revenue
External customers		5,899,600			7,963,714			8,211,099			5,325,622			—			—			27,400,035
Inter-segment		—			—			—			—			43,808			(43,808	)		—

Total revenue		5,899,600			7,963,714			8,211,099			5,325,622			43,808			(43,808	)		27,400,035

Operating profit (loss)		1,814,021			857,304			2,336,394			561,642			(6,987	)		15			5,562,389

Depreciation expenses		(921,999	)		(576,138	)		(2,579,150	)		(549,020	)		(7,805	)		—			(4,634,112	)

Share of profit (loss) of associates		—			—			—			—			1,211,177			(585,444	)		625,733

Interest income		—			—			—			—			9,980			—			9,980

Interest expense		—			—			—			—			(120,998	)		—			(120,998	)

Purchase of property, plant and equipment		1,841,359			1,553,475			2,748,697			408,751			420			—			6,552,702

Reconciliation for segment income (loss)

Revenue from external customers and segment income (loss) reported to the chief operating decision maker are measured using the same method as for revenue and operating profit in the financial statements. Thus, no reconciliation is needed.

Information on products and services


	Year ended December 31,
	2019				2020				2021
	NT$000		%		NT$000		%		NT$000		%
Testing		4,257,800		21		5,002,730		22		5,899,600		22
Assembly		5,148,877		25		6,001,964		26		7,963,714		29
LCDD		6,922,205		34		7,023,003		30		8,211,099		30
Bumping		4,008,999		20		4,983,684		22		5,325,622		19

		20,337,881		100		23,011,381		100		27,400,035		100

Geographical information


	Year ended December 31,
	2019		2020		2021
	NT$000		NT$000		NT$000
Revenue
ROC		15,875,027		18,341,726		21,608,567
Japan		1,905,032		1,291,026		1,768,460
Singapore		1,333,114		1,838,394		1,630,733
PRC		789,496		1,105,535		1,899,362
Others		435,212		434,700		492,913

		20,337,881		23,011,381		27,400,035


	December 31, 2020		December 31, 2021
	NT$000		NT$000
Non-current assets
ROC		18,913,501		21,506,565
PRC		117		86
Others		11,845		6,245

		18,925,463		21,512,896

Major customer information

The information on the major customers which constituted more than 10% of the Group’s total revenue for the years ended December 31, 2019, 2020 and 2021 is as follows:


	Year ended December 31,
	2019				2020				2021
	Amount		%		Amount		%		Amount		%
	NT$000				NT$000				NT$000
Customers
Customer A		4,756,755		23		5,088,544		22		5,681,277		21
Customer M		1,259,269		6		1,674,801		7		2,832,088		10
Customer K		2,419,612		12		2,332,914		10		2,519,631		9
Customer B		1,679,344		8		2,365,945		10		2,484,611		9
Customer C		2,048,260		10		2,143,130		9		2,268,439		8

Financial Statements Schedule: Valuation and Qualifying Accounts

12 Months Ended

Dec. 31, 2021

Financial Statements Schedule: Valuation and Qualifying Accounts

45.	Financial Statements Schedule: Valuation and Qualifying Accounts


	January 1		Additions charged to expense or deduction of revenue		Deduction / Write-offs / Reversal			December 31
	NT$000		NT$000		NT$000			NT$000
Year of 2019 :
Allowance for impairment of property, plant and equipment		317,593		9,938		(134,191	)		193,340
Allowance for impairment of obsolescence and decline in market value of inventories		36,157		27,341		—			63,498
Provision for deficiency compensation		29,352		5,204		(32,558	)		1,998
Sales for allowance		32,627		63,863		(70,490	)		26,000
Year of 2020 :
Allowance for impairment of property, plant and equipment		193,340		—		(11,338	)		182,002
Allowance for impairment of obsolescence and decline in market value of inventories		63,498		16,317		—			79,815
Provision for deficiency compensation		1,998		4,358		(2,893	)		3,463
Sales for allowance		26,000		21,916		(38,052	)		9,864


	January 1		Additions charged to expense or deduction of revenue		Deduction / Write-offs / Reversal			December 31
	NT$000		NT$000		NT$000			NT$000
Year of 2021 :
Allowance for impairment of property, plant and equipment		182,002		4,843		(3,666	)		183,179
Allowance for impairment of obsolescence and decline in market value of inventories		79,815		41,771		—			121,586
Provision for deficiency compensation		3,463		11,898		(11,080	)		4,281
Sales for allowance		9,864		34,744		(34,759	)		9,849

For movements in loss allowance for contract assets, accounts receivable, and other receivables, please refer to Note 43.

Summary of significant accounting policies (Policies)

12 Months Ended

Dec. 31, 2021

Foreign currency translation

Statement of compliance

The consolidated financial statements of the Group have been prepared in accordance with IFRSs as issued by the IASB.

Basis of preparation

(a)

Except for the following items, the consolidated financial statements have been prepared under the historical cost convention:

Financial assets at fair value through profit or loss (including derivative instruments).

ii)

Financial assets at fair value through other comprehensive income.

iii)

Defined benefit liabilities were recognized based on the net amount of pension fund assets less the present value of benefit obligation.

(b)

(c)

These consolidated financial statements are presented in New Taiwan dollars (“NT$”), which is the Company’s functional currency.

Basis of consolidation

(a)

Basis for preparation of consolidated financial statements:

ii)

iii)

Profit or loss and each component of other comprehensive income are attributed to the owners of the parent and to the

non-controlling

interests. Total comprehensive income is attributed to the owners of the parent and to the

non-controlling

interests even if this results in a deficit balance in the

non-controlling

interests.

iv)

Changes in a parent’s ownership interest in a subsidiary that do not result in the parent losing control of the subsidiary (transactions with

non-controlling

interests) are accounted for as equity transactions, i.e. transactions with owners in their capacity as owners. Any difference between the amount by which the

non-controlling

interests are adjusted and the fair value of the consideration paid or received is recognized directly in equity.

(b)

Subsidiaries included in the consolidated financial statements:

Percentage of

Ownership (%)

December 31,

Name of investor

Name of investee

Main business

Location

2020

2021

Note

The Company

ChipMOS U.S.A., Inc. (“ChipMOS USA”)

Marketing of semiconductors and electronic related products

San Jose, USA

100

The Company

ChipMOS TECHNOLOGIES (BVI) LTD.

(“ChipMOS BVI”)

Holding company

British Virgin Islands

100

ChipMOS BVI

ChipMOS SEMICONDUCTORS (Shanghai) LTD. (“ChipMOS Shanghai”)

Marketing of semiconductors and electronic related products

Shanghai, People’s Republic of China (“PRC”)

100

(c)

Subsidiaries not included in the consolidated financial statements: None.

(d)

Adjustments for subsidiaries with different statements of financial position dates: Not applicable.

(e)

No significant restrictions on the ability of subsidiaries to transfer funds to parent company.

(f)

Subsidiaries that have

non-controlling

interests that are material to the Group: None.

(a)

Foreign currency transactions and balances

ii)

Monetary assets and liabilities denominated in foreign currencies at the period end are

re-translated

at the exchange rates prevailing at the statements of financial position date. Exchange differences arising upon

re-translation

are recognized in profit or loss on the statements of financial position date.

iii)

Non-monetary

assets and liabilities denominated in foreign currencies held at fair value through profit or loss are

re-translated

at the exchange rates prevailing at the statements of financial position date; their exchange differences are recognized in profit or loss.

Non-monetary

assets and liabilities denominated in foreign currencies held at fair value through other comprehensive income are

re-translated

at the exchange rates prevailing at the statements of financial position date; their exchange differences are recognized in other comprehensive income. However,

non-monetary

assets and liabilities denominated in foreign currencies that are not measured at fair value are translated using the historical exchange rates at the initial dates of the transactions.

iv)

All foreign exchange differences are presented in the statement of comprehensive income under “Other gains and losses” by the nature of transactions.

(b)

Translation of foreign operations

Assets and liabilities for each statements of financial position are translated at the exchange rates prevailing at the statements of financial position date;

ii)

Income and expenses for each statement of comprehensive income are translated at average exchange rates of that period; and

iii)

All exchange differences are recognized in other comprehensive income.

Classification of current and non-current assets and liabilities

Classification of current and

non-current

assets and liabilities

(a)

Assets that meet one of the following criteria are classified as current assets:

Assets arising from operating activities that are expected to be realized, or are intended to be sold or consumed within the normal operating cycle;

ii)

Assets held mainly for trading purposes;

iii)

Assets that are expected to be realized within 12 months from the statements of financial position date;

iv)

All assets that do not meet the above criteria are classified as

non-current

assets.

(b)

Liabilities that meet one of the following criteria are classified as current liabilities:

Liabilities that are expected to be settled within the normal operating cycle;

ii)

Liabilities arising mainly from trading activities;

iii)

Liabilities that are to be settled within 12 months from the statements of financial position date;

iv)

All liabilities that do not meet the above criteria are classified as

non-current

liabilities.

Cash equivalents

Financial assets at fair value through profit or loss

(a)

Financial assets at fair value through profit or loss are financial assets that are not measured at amortized cost or fair value through other comprehensive income.

(b)

On a regular way purchase or sale basis, financial assets at fair value through profit or loss are recognized and derecognized using settlement date accounting.

(c)

(d)

Financial assets at fair value through other comprehensive income

(a)

(b)

On a regular way purchase or sale basis, financial assets at fair value through other comprehensive income are recognized and derecognized using settlement date accounting.

(c)

At initial recognition, the Group measures the financial assets at fair value plus transaction costs. The Group subsequently measures the financial assets at fair value.

Financial assets at amortized cost

(a)

Financial assets at amortized cost are those that meet all of the following criteria:

The objective of the Group’s business model is achieved by collecting contractual cash flows.

ii)

The financial assets’ contractual cash flows represent solely payments of principal and interest.

(b)

The Group’s time deposits which do not fall under cash equivalents are those with a short maturity period and are measured at initial investment amount as the effect of discounting is immaterial.

Accounts and notes receivable

(a)

Accounts and notes receivable entitle the Group a legal right to receive consideration in exchange for transferred goods or rendered services.

(b)

The short-term accounts and notes receivable without bearing interest are subsequently measured at initial invoice amount as the effect of discounting is immaterial.

Impairment of financial assets

Derecognition of financial assets

The Group derecognizes a financial asset when the contractual rights to receive the cash flows from the financial asset have expired.

Inventories

Investments accounted for using equity method – associates

(a)

(b)

(c)

(d)

(e)

(f)

Property, plant and equipment

(a)

Property, plant and equipment are initially recorded at cost. Borrowing costs incurred during the construction period are capitalized.

(b)

(c)

(d)

The assets’ residual values, useful lives and depreciation methods are reviewed, and adjusted if appropriate, at each financial

year-end.


Buildings		5 to 51 years
Machinery and equipment		2 to 8 years
Tools		2 to 4 years
Others		2 to 6 years

Leasing arrangements (lessee) – right-of-use assets / lease liabilities

Leasing arrangements (lessee)

–

right-of-use assets / lease liabilities

(a)

Leases are recognized as a

right-of-use

(b)

Lease liabilities include the net present value of the remaining lease payments at the commencement date, discounted using the incremental borrowing interest rate.

Lease payments are comprised of the following:

Fixed payments, less any lease incentives receivable;

ii)

The exercise price of a purchase option, if the lessee is reasonably certain to exercise that option.

right-of-use

asset when there are changes in the lease term or lease payments and such changes do not arise from contract modifications.

(c)

At the commencement date, the

right-of-use

asset is stated at the amount of the initial measurement of lease liability. The

right-of-use

asset.

Impairment of non-financial assets

Impairment of

non-financial

assets

Loans

Accounts and notes payable

(a)

Accounts payable are liabilities for purchases of raw materials, goods or services and notes payable are those resulting from operating and

non-operating

activities.

(b)

The short-term accounts and notes payable without bearing interest are subsequently measured at initial invoice amount as the effect of discounting is immaterial.

Derecognition of financial liabilities

A financial liability is derecognized when the obligation specified in the contract is either discharged or cancelled or expires.

Provisions for deficiency compensation

pre-tax

Employee benefits

(a)

Short-term employee benefits

(b)

Pensions

Defined contribution plans

ii)

Defined benefit plans

Remeasurements arising on defined benefit plans are recognized in other comprehensive income in the period in which they arise and are recorded as retained earnings.

Past service costs are recognized immediately in profit or loss.

(c)

Termination benefits

(d)

Employees’ compensation and directors’ remuneration

Employee share-based payments

Restricted shares

(a)

Restricted shares issued to employees are measured at the fair value of the equity instruments granted at the grant date, and are recognized as compensation cost over the vesting period.

(b)

(c)

For restricted shares where employees do not need to pay to acquire those shares, if an employee resigns during the vesting period, the Group will recover and retire those shares at no cost.

Income tax

(a)

(b)

(c)

(d)

(e)

(f)

Capital stock

(a)

Ordinary shares are classified as equity. Incremental costs directly attributable to the issue of new shares in net proceeds of tax are shown in equity as a deduction.

(b)

Dividends

Revenue recognition

aa)

Revenue recognition

(a)

Customer controls the provided raw materials and the Group receives the instruction from the customer on providing assembly and testing services and subsequent treatments.

ii)

The Group provides assembly and testing services to create or enhance an asset which is solely provided and controlled by the customer. The Group has no right to transfer the asset for another use.

(b)

Government grants

bb)

Government grants

non-current

liabilities and are amortized to profit or loss over the estimated useful lives of the related assets using straight-line method.

Operating segments

cc)

Operating segments

Critical accounting judgments, estimates and key sources of assumption uncertainty

dd)

Critical accounting judgments, estimates and key sources of assumption uncertainty

Critical accounting estimates and assumptions

Revenue recognition

Summary of significant accounting policies (Tables)

12 Months Ended

Dec. 31, 2021

Summary of Ownership Interests in Subsidiaries

Percentage of

Ownership (%)

December 31,

Name of investor

Name of investee

Main business

Location

2020

2021

Note

The Company

ChipMOS U.S.A., Inc. (“ChipMOS USA”)

Marketing of semiconductors and electronic related products

San Jose, USA

100

The Company

ChipMOS TECHNOLOGIES (BVI) LTD.

(“ChipMOS BVI”)

Holding company

British Virgin Islands

100

ChipMOS BVI

ChipMOS SEMICONDUCTORS (Shanghai) LTD. (“ChipMOS Shanghai”)

Marketing of semiconductors and electronic related products

Shanghai, People’s Republic of China (“PRC”)

100

Estimated Useful Life for Depreciation of Individual Assets


Buildings		5 to 51 years
Machinery and equipment		2 to 8 years
Tools		2 to 4 years
Others		2 to 6 years

Cash and cash equivalents (Tables)

12 Months Ended

Dec. 31, 2021

Summary of Cash and Cash Equivalents


	December 31, 2020		December 31, 2021
	NT$000		NT$000
Cash on hand and petty cash		470		450
Checking accounts and demand deposits		2,609,421		2,683,977
Time deposits		1,503,760		3,221,749

		4,113,651		5,906,176

The Group transacts with a variety of financial institutions all with high credit quality to disperse credit risk, so it expects that the probability of counterparty default is remote.

No cash and cash equivalents of the Group were pledged to others.

Financial assets at fair value through profit or loss (Tables)

12 Months Ended

Dec. 31, 2021

Summary of Financial Assets at Fair Value Through Profit or Loss


	December 31, 2020			December 31, 2021
	NT$000			NT$000
Current:
Financial assets mandatorily measured at fair value through profit or loss
Listed stocks		46,512			339,679
Valuation adjustment		6,608			20,281

		53,120			359,960

Non-current:
Financial assets mandatorily measured at fair value through profit or loss
Foreign partnership interests		10,940			—
Valuation adjustment		(572	)		—

		10,368			—

Summary of Amounts recognized in Profit or Loss in Relation to Financial Assets at Fair Value Through Profit or Loss

Amounts recognized in profit or loss in relation to the financial assets at fair value through profit or loss are listed below:


	Year ended December 31,
	2019			2020			2021
	NT$000			NT$000			NT$000
Financial assets mandatorily measured at fair value through profit or loss
Beneficiary certificates*		1,750			18,077			2,530
Listed stocks		—			6,608			13,673
Foreign partnership interests		(433	)		(670	)		(941	)

		1,317			24,015			15,262

No financial assets at FVTPL were pledged to others.

Information relating to price risk of financial assets at FVTPL is provided in Note 43.

Financial assets at amortized cost (Tables)

12 Months Ended

Dec. 31, 2021

Summary of Financial Assets at Amortized Cost


	December 31, 2020		December 31, 2021
	NT$000		NT$000
Current:
Time deposits		206,482		29,239

Non-current:
Restricted bank deposits		48,319		37,539

Amounts recognized in profit or loss in relation to financial assets at amortized cost are listed below:


	Year ended December 31,
	2019		2020		2021
	NT$000		NT$000		NT$000
Interest income		4,467		2,206		1,187

Accounts receivable (Tables)

12 Months Ended

Dec. 31, 2021

Summary of Accounts and notes receivable


	December 31, 2020			December 31, 2021
	NT$000			NT$000
Accounts receivable		5,365,776			6,346,156
Less: Loss allowance		(1,620	)		(1,910	)

		5,364,156			6,344,246

Aging of Accounts Receivable which are Past Due but not Impaired


	December 31, 2020		December 31, 2021
	NT$000		NT$000
Current		5,272,208		6,327,791
Within 1 month		93,568		18,365

		5,365,776		6,346,156

Inventories (Tables)

12 Months Ended

Dec. 31, 2021

Cost of Inventories Recognized as an Expense

Summary of Inventories

December 31, 2020

Cost

Allowance for

impairment losses

Carrying amount

NT$000

Raw materials

2,181,890

(79,815

)

2,102,075

December 31, 2021

Cost

Allowance for

impairment losses

Carrying amount

NT$000

Raw materials

3,328,763

(121,586

)

3,207,177

The cost of inventories recognized as an expense for the year:


	Year ended December 31,
	2019		2020		2021
	NT$000		NT$000		NT$000
Cost of revenue		16,372,032		17,957,568		20,103,735
Loss on abandonment		12,369		5,323		552
Allowance for inventory valuation and obsolescence loss		27,341		16,317		41,770

		16,411,742		17,979,208		20,146,057

Non-current financial assets at fair value through other comprehensive income (Tables)

12 Months Ended

Dec. 31, 2021

Summary of Non-current Financial Assets at Fair Value Through Other Comprehensive Income


	December 31, 2020		December 31, 2021
	NT$000		NT$000
Designation of equity instruments
Foreign unlisted stocks		38,534		38,534
Valuation adjustment		223,473		345,987

		262,007		384,521

Summary Amounts recognized in other comprehensive income in relation to the financial assets at fair value through other comprehensive income

Amounts recognized in other comprehensive income in relation to the financial assets at fair value through other comprehensive income are listed below:


	Year ended December 31,
	2019			2020		2021
	NT$000			NT$000		NT$000
Financial assets at fair value through other comprehensive income
Foreign unlisted stocks		(52,549	)		140,199		122,514

Investments accounted for using equity method (Tables)

12 Months Ended

Dec. 31, 2021

Investments accounted for using equity method [abstract]

Details of Investment in Associates


Associates	December 31, 2020		December 31, 2021
	NT$000		NT$000
JMC ELECTRONICS CO., LTD. (“JMC”)		250,769		304,437
Unimos Microelectronics (Shanghai) Co., Ltd. (“Unimos Shanghai”)		3,020,908		3,596,012

		3,271,677		3,900,449

Summarized Financial Information for Investment in Material Associates


	Year ended December 31,
	2019			2020			2021
	NT$000			NT$000			NT$000
(Loss) profit for the year from continuing operations		(154,926	)		(147,329	)		625,733
Other comprehensive income, net of income tax		5,732			23,143			28,843

Total comprehensive (loss) income		(149,194	)		(124,186	)		654,576

Property, plant and equipment, net (Tables)

12 Months Ended

Dec. 31, 2021

Summary of Property, Plant and Equipment, Net


	2019
	Land		Buildings			Machinery and equipment			Tools			Others			Construction in progress and equipment to be inspected			Total
	NT$000		NT$000			NT$000			NT$000			NT$000			NT$000			NT$000
January 1
Cost		452,738		10,254,531			48,274,171			4,402,711			2,610,893			1,069,892			67,064,936
Accumulated depreciation and impairment		—		(6,345,800	)		(38,042,078	)		(3,660,532	)		(2,196,905	)		—			(50,245,315	)

		452,738		3,908,731			10,232,093			742,179			413,988			1,069,892			16,819,621

January 1		452,738		3,908,731			10,232,093			742,179			413,988			1,069,892			16,819,621
Effects on initial application of IFRS 16		—		—			—			—			(31,904	)		—			(31,904	)

Adjusted balance at January 1		452,738		3,908,731			10,232,093			742,179			382,084			1,069,892			16,787,717
Additions		—		116,238			2,334,358			781,465			224,287			1,440,308			4,896,656
Disposals		—		—			(16,033	)		(9,336	)		(416	)		—			(25,785	)
Reclassifications		—		455,792			1,111,715			7,880			25,042			(1,573,811	)		26,618
Depreciation expenses		—		(384,832	)		(2,489,070	)		(625,712	)		(196,201	)		—			(3,695,815	)
Impairment losses		—		—			(9,938	)		—			—			—			(9,938	)
Exchange adjustment		—		—			(4	)		—			(5	)		—			(9	)

December 31		452,738		4,095,929			11,163,121			896,476			434,791			936,389			17,979,444

December 31
Cost		452,738		10,821,972			51,244,512			5,008,321			1,937,755			936,389			70,401,687
Accumulated depreciation and impairment		—		(6,726,043	)		(40,081,391	)		(4,111,845	)		(1,502,964	)		—			(52,422,243	)

		452,738		4,095,929			11,163,121			896,476			434,791			936,389			17,979,444


	2020
	Land		Buildings			Machinery and equipment			Tools			Others			Construction in progress and equipment to be inspected			Total
	NT$000		NT$000			NT$000			NT$000			NT$000			NT$000			NT$000
January 1
Cost		452,738		10,821,972			51,244,512			5,008,321			1,937,755			936,389			70,401,687
Accumulated depreciation and impairment		—		(6,726,043	)		(40,081,391	)		(4,111,845	)		(1,502,964	)		—			(52,422,243	)

		452,738		4,095,929			11,163,121			896,476			434,791			936,389			17,979,444

January 1		452,738		4,095,929			11,163,121			896,476			434,791			936,389			17,979,444
Additions		—		132,572			592,565			409,832			142,776			2,855,870			4,133,615
Disposals		—		—			(8,940	)		(3,121	)		(7,297	)		—			(19,358	)
Reclassifications		—		258,421			2,336,238			398,798			159,195			(3,152,652	)		—
Depreciation expenses		—		(394,636	)		(2,734,667	)		(749,624	)		(220,066	)		—			(4,098,993	)
Exchange adjustment		—		—			(20	)		—			(2	)		—			(22	)

December 31		452,738		4,092,286			11,348,297			952,361			509,397			639,607			17,994,686

December 31
Cost		452,738		11,212,129			53,246,474			5,451,547			2,185,299			639,607			73,187,794
Accumulated depreciation and impairment		—		(7,119,843	)		(41,898,177	)		(4,499,186	)		(1,675,902	)		—			(55,193,108	)

		452,738		4,092,286			11,348,297			952,361			509,397			639,607			17,994,686


	2021
	Land		Buildings			Machinery and equipment			Tools			Others			Construction in progress and equipment to be inspected			Total
	NT$000		NT$000			NT$000			NT$000			NT$000			NT$000			NT$000
January 1
Cost		452,738		11,212,129			53,246,474			5,451,547			2,185,299			639,607			73,187,794
Accumulated depreciation and impairment		—		(7,119,843	)		(41,898,177	)		(4,499,186	)		(1,675,902	)		—			(55,193,108	)

		452,738		4,092,286			11,348,297			952,361			509,397			639,607			17,994,686

January 1		452,738		4,092,286			11,348,297			952,361			509,397			639,607			17,994,686
Additions		—		1,345			11,829			407			189			6,538,932			6,552,702
Disposals		—		—			(66,873	)		(9,502	)		—			—			(76,375	)
Reclassifications		—		673,208			4,890,400			690,346			241,656			(6,495,610	)		—
Depreciation expenses		—		(423,283	)		(2,896,612	)		(795,622	)		(239,515	)		—			(4,355,032	)
Impairment losses		—		—			(4,843	)		—			—			—			(4,843	)
Exchange adjustment		—		—			(13	)		—			(4	)		—			(17	)

December 31		452,738		4,343,556			13,282,185			837,990			511,723			682,929			20,111,121

December 31
Cost		452,738		11,877,419			57,176,339			5,574,316			2,345,204			682,929			78,108,945
Accumulated depreciation and impairment		—		(7,533,863	)		(43,894,154	)		(4,736,326	)		(1,833,481	)		—			(57,997,824	)

		452,738		4,343,556			13,282,185			837,990			511,723			682,929			20,111,121

Capitalization Interest and Capitalization Interest Rate Applied Related to Property, Plant and Equipment


	Year ended December 31,
	2019			2020			2021
	NT$000			NT$000			NT$000
Amount of interest capitalized		15,114			9,762			11,193
Range of the interest rates for capitalization		1.7822	%		1.4909	%		1.1358	%

Leasing arrangements - leasee (Tables)

12 Months Ended

Dec. 31, 2021

Presentation of leases for lessee [abstract]

Summary of carrying amount of right-of-use assets and the depreciation expenses


	December 31, 2020		December 31, 2021
	Carrying amount		Carrying amount
	NT$000		NT$000
Land		636,261		616,458
Buildings		19,044		10,946
Machinery and equipment		203,249		204,484
Others		515		3,917

		859,069		835,805


	Year ended December 31,
	2019		2020		2021
	Depreciation expenses		Depreciation expenses		Depreciation expenses
	NT$000		NT$000		NT$000
Land		22,657		20,938		20,486
Buildings		7,113		7,819		9,870
Machinery and equipment		4,520		46,225		247,090
Others		1,809		1,544		1,634

		36,099		76,526		279,080

Summary of profit and loss accounts relating to lease contracts

The information on profit or loss accounts relating to lease contracts is as follows:


	Year ended December 31,
	2019		2020		2021
	NT$000		NT$000		NT$000
Items affecting profit or loss
Interest expense on lease liabilities		14,349		13,442		15,245
Expense on short-term lease contracts		230,589		202,782		143,791

Short-term bank loans (Tables)

12 Months Ended

Dec. 31, 2021

Short Term Borrowings Abstract [Abstract]

Summary of Short-term bank loans


Type of loans	December 31, 2020		December 31, 2021
	NT$000		NT$000
Bank loans
Unsecured bank loans		—		731,751

Interest rate range		—		0.6604%~0.7394	%

Unused credit lines of short-term bank loans
NT$000		3,251,000		2,918,249

US$000		90,000		85,025

Accounts payable (Tables)

12 Months Ended

Dec. 31, 2021

Disclosure Of Detailed Information Of Trade And Other Payable Explanatory [Abstract]

Summary of Accounts Payable


	December 31, 2020		December 31, 2021
	NT$000		NT$000
Accounts payable		766,805		765,403
Estimated accounts payable		200,016		246,988

		966,821		1,012,391

Other Payables (Tables)

12 Months Ended

Dec. 31, 2021

Summary of Other Payables


	December 31, 2020		December 31, 2021
	NT$000		NT$000
Payables to contractors and equipment suppliers		1,145,359		1,816,555
Salaries and bonuses payable		788,720		829,762
Employees’ compensation payable		332,080		673,387
Directors’ remuneration payable		16,604		25,690
Pension payable		15,159		16,600
Interest payable		1,958		3,277
Other expense payable		949,523		1,013,168

		3,249,403		4,378,439

Long-term bank loans (Tables)

12 Months Ended

Dec. 31, 2021

Statement [LineItems]

Summary of Bank Loans


Type of loans	Period and payment term	December 31, 2020			December 31, 2021
		NT$000			NT$000
Syndicated bank loan	Borrowing period is from May 30, 2018 to May 30, 2023; interest is repayable monthly; principal is repayable semi-annually from November 30, 2018		3,310,000			54,000
Government granted bank loans	Borrowing period is from March 11, 2020 to November 15, 2031; interest is repayable monthly; principal is repayable monthly from March 15, 2023		4,505,000			9,463,131
Less: Fee on syndicated bank loan			(17,223	)		(10,026	)
Less: Unamortized interest on government granted bank loans			(64,212	)		(93,740	)
Less: Current portion (fee included)			(748,353	)		(46,826	)

			6,985,212			9,366,539

Interest rate range			0.65%~1.7895	%		0.45%~1.7895	%

Unused credit lines of long-term bank loan NT$000			11,239,000			8,776,868

Pensions (Tables)

12 Months Ended

Dec. 31, 2021

Summary of Amounts Recognized in Statements of Financial Position

(a)

The amounts recognized in the statements of financial position are as follows:


	December 31, 2020			December 31, 2021
	NT$000			NT$000
Present value of defined benefit obligations		(943,391	)		(959,677	)
Fair value of plan assets		431,740			456,389

Net defined benefit liability		(511,651	)		(503,288	)

Summary of Movements in net Defined Benefit Liability

(b)

Movements in net defined benefit liability are as follows:


	2019
	Present value of defined benefit obligations			Fair value of plan assets			Net defined benefit liability
	NT$000			NT$000			NT$000
January 1		(910,081	)		389,316			(520,765	)
Current services cost		(332	)		—			(332	)
Interest (expense) income		(11,170	)		4,831			(6,339	)

		(921,583	)		394,147			(527,436	)

Remeasurements:
Return on plan assets (excluding amounts included in interest income or expense)		—			12,601			12,601
Financial assumption movement effect		(27,993	)		—			(27,993	)
Experience adjustments		36,308			—			36,308

		8,315			12,601			20,916

Pension fund contribution		—			26,413			26,413
Paid pension		12,109			(12,109	)		—

December 31		(901,159	)		421,052			(480,107	)


	2020
	Present value of defined benefit obligations			Fair value of plan assets			Net defined benefit liability
	NT$000			NT$000			NT$000
January 1		(901,159	)		421,052			(480,107	)
Current services cost		(263	)		—			(263	)
Interest (expense) income		(8,835	)		4,171			(4,664	)

		(910,257	)		425,223			(485,034	)

Remeasurements:
Return on plan assets (excluding amounts included in interest income or expense)		—			12,568			12,568
Financial assumption movement effect		(57,180	)		—			(57,180	)
Experience adjustments		(7,378	)		—			(7,378	)

		(64,558	)		12,568			(51,990	)

Pension fund contribution		—			25,373			25,373
Paid pension		31,424			(31,424	)		—

December 31		(943,391	)		431,740			(511,651	)


	2021
	Present value of defined benefit obligations			Fair value of plan assets			Net defined benefit liability
	NT$000			NT$000			NT$000
January 1		(943,391	)		431,740			(511,651	)
Current services cost		(237	)		—			(237	)
Interest (expense) income		(4,629	)		2,137			(2,492	)

		(948,257	)		433,877			(514,380	)

Remeasurements:
Return on plan assets (excluding amounts included in interest income or expense)		—			5,613			5,613
Impact on changes in demographic assumptions		(20,022	)		—			(20,022	)
Financial assumption movement effect		23,757			—			23,757
Experience adjustments		(24,347	)		—			(24,347	)

		(20,612	)		5,613			(14,999	)

Pension fund contribution		—			26,091			26,091
Paid pension		9,192			(9,192	)		—

December 31		(959,677	)		456,389			(503,288	)

Principal Actuarial Assumptions

(d)

The principal actuarial assumptions used were as follows:


	Year ended December 31,
	2020			2021
Discount rate		0.50	%		0.70	%

Future salary increase		3.50	%		3.50	%

Sensitivity Analysis of Present Value of Defined Benefit Obligations Effected by Changes of Significant Actuarial Assumptions

The present value of defined benefit obligations is affected by the change in actuarial assumption. The analysis was as follows:


	Discount rate					Future salary increase
	Increase 0.25%			Decrease 0.25%		Increase 0.25%		Decrease 0.25%
	NT$000			NT$000		NT$000		NT$000
December 31, 2020
Effect on present value of defined benefit obligations		(29,114	)		30,434		29,471		(28,365	)

December 31, 2021
Effect on present value of defined benefit obligations		(28,574	)		29,825		28,941		(27,893	)

Analysis of Timing of the Future Pension Payment

(f)

As of December 31, 2021, the weighted average duration of that retirement plan is 12.2 years. The analysis of timing of the future pension payment was as follows:


	December 31, 2021
	NT$000
Within 1 year		36,762
1-2 years		36,346
2-5 years		126,806
5-10 years		178,998

		378,912

Share-based payments (Tables)

12 Months Ended

Dec. 31, 2021

Issuance of Restricted Shares

Type of

arrangement

Grant
date

Share price
on grant date
(in NT$)

Number of
shares
(in thousands)

Contract
period

Vesting condition

Restricted shares award agreement

July 21,
2015

36.1

15,752

3 years

Meet service and performance conditions

Restricted shares award agreement

May 10,
2016

30.6

1,548

3 years

Meet service and performance conditions

Capital stock (Tables)

12 Months Ended

Dec. 31, 2021

Movement of Ordinary Shares Issued

Movements in the number of the Company’s ordinary shares outstanding are as follows:


	2019			2020		2021
	in thousands			in thousands		in thousands
January 1		727,265			727,240		727,240
Restricted shares – cancelled		(25	)		—		—

December 31		727,240			727,240		727,240

Capital surplus (Tables)

12 Months Ended

Dec. 31, 2021

Summary of Capital Surplus


	2019
	Share premium			Employee restricted shares			Others		Total
	NT$000			NT$000			NT$000		NT$000
January 1		5,873,743			382,506			7,304		6,263,553
Share-based payments		—			(412	)		—		(412	)
Cancellation of treasury stock		(199,501	)		(12,853	)		—		(212,354	)

December 31		5,674,242			369,241			7,304		6,050,787


	2020
	Share premium		Employee restricted shares			Others		Total
	NT$000		NT$000			NT$000		NT$000
January 1		5,674,242		369,241			7,304		6,050,787
Reclassifications		369,241		(369,241	)		—		—

December 31		6,043,483		—			7,304		6,050,787


	2021
	Share premium		Employee restricted shares		Others		Total
	NT$000		NT$000		NT$000		NT$000
January 1		6,043,483		—		7,304		6,050,787
Changes in associates accounted for using equity method		—		—		4,834		4,834

December 31		6,043,483		—		12,138		6,055,621

Retained earnings (Tables)

12 Months Ended

Dec. 31, 2021

Summary of Distribution Towards Legal Reserve and Cash Dividend


	2018				2019				2020
	Amount		Cash distribution per share		Amount		Cash distribution per share		Amount			Cash distribution per share
	Amount		Cash distribution per share		Amount		Cash distribution per share		Amount			Cash distribution per share
	NT$000		NT$		NT$000		NT$		NT$000			NT$
Legal reserve		110,308				258,416				232,611
Special reserve		—				19,802				(19,802	)
Cash dividend		872,718		1.20		1,309,032		1.80		1,599,928			2.20

Other equity interest (Tables)

12 Months Ended

Dec. 31, 2021

Other Equity Interests [Abstract]

Summary of Other Equity Interest


	2019
	Financial statements translation differences of foreign operations			Unrealized gain (loss) on valuation of financial assets at fair value through other comprehensive income			Unearned employee awards			Total
	NT$000			NT$000			NT$000			NT$000
January 1		14,516			106,898			(1,701	)		119,713
Currency translation differences
- The Company		(104,198	)		—			—			(104,198	)
Employee restricted shares
- The Company		—			—			1,701			1,701
Evaluation adjustment
- The Company		—			(52,549	)		—			(52,549	)
- Associates		—			5,093			—			5,093
Evaluation adjustment related tax
- The Company		—			7,016			—			7,016
Disposal of investment accounted for using equity method		—			(72	)		—			(72	)

December 31		(89,682	)		66,386			—			(23,296	)


	2020
	Financial statements translation differences of foreign operations			Unrealized gain (loss) on valuation of financial assets at fair value through other comprehensive income			Total
	NT$000			NT$000			NT$000
January 1		(89,682	)		66,386			(23,296	)
Currency translation differences
- The Company		28,352			—			28,352
Evaluation adjustment
- The Company		—			140,199			140,199
- Associates		—			22,925			22,925
Evaluation adjustment related tax
- The Company		—			(34,794	)		(34,794	)

December 31		(61,330	)		194,716			133,386


	2021
	Financial statements translation differences of foreign operations			Unrealized gain (loss) on valuation of financial assets at fair value through other comprehensive income			Total
	NT$000			NT$000			NT$000
January 1		(61,330	)		194,716			133,386
Currency translation differences
- The Company		(24,695	)		—			(24,695	)
Evaluation adjustment
- The Company		—			122,514			122,514
- Associates		—			21,094			21,094
Evaluation adjustment related tax
- The Company		—			(30,459	)		(30,459	)

December 31		(86,025	)		307,865			221,840

Revenue (Tables)

12 Months Ended

Dec. 31, 2021

Summary of Revenue from Contracts with Customers


	Year ended December 31,
	2019		2020		2021
	NT$000		NT$000		NT$000
Revenue from contracts with customers		20,337,881		23,011,381		27,400,035

Summary of Contract Assets and Liabilities

The Group has recognized the following contract assets and liabilities in relation to revenue from contracts with customers:


	January 1, 2020		December 31, 2020		December 31, 2021
	NT$000		NT$000		NT$000
Contract assets		377,869		389,016		400,255

Contract liabilities (Advance payments)		1,231		—		—

Other income (expenses), net (Tables)

12 Months Ended

Dec. 31, 2021

Summary of Other Income (Expenses), Net


	Year ended December 31,
	2019			2020		2021
	NT$000			NT$000		NT$000
Gain on disposal of scrapped materials		43,652			51,077		52,254
Royalty income		12,336			2,962		907
Gain on disposal of items purchased on behalf of others		15,080			30,140		21,945
Gain on disposal of property, plant and equipment, net		20,271			48,070		33,935
Insurance compensation income		10,435			—		—
Impairment loss on property, plant and equipment		(9,938	)		—		(4,843	)
Gains from lease modifications		—			—		891
Others		1,092			3,329		20,498

		92,928			135,578		125,587

Interest income (Tables)

12 Months Ended

Dec. 31, 2021

Disclosure of Interest Income [Abstract]

Disclosure of Interest Income


	Year ended December 31,
	2019		2020		2021
	NT$000		NT$000		NT$000
Bank deposits		59,901		25,547		8,772
Financial assets at amortized cost		4,467		2,206		1,187
Other interest income		—		25		21

		64,368		27,778		9,980

Other income (Tables)

12 Months Ended

Dec. 31, 2021

Summary of Other income


	Year ended December 31,
	2019		2020		2021
	NT$000		NT$000		NT$000
Rental income		9,249		10,260		17,326
Dividend income		585		3,229		4,690
Grant income		925		7,668		12,480

		10,759		21,157		34,496

Other gains and losses (Tables)

12 Months Ended

Dec. 31, 2021

Summary of Other gains and losses


	Year ended December 31,
	2019			2020			2021
	NT$000			NT$000			NT$000
Foreign exchange losses, net		(154,993	)		(355,255	)		(89,152	)
Reimbursement of ADSs service charge		4,292			2,101			2,284
Gain on valuation of financial assets at fair value through profit or loss		1,317			24,015			15,262
Compensation income		—			—			1,524
Others		970			5,872			4,253

		(148,414	)		(323,267	)		(65,829	)

Finance costs (Tables)

12 Months Ended

Dec. 31, 2021

Analysis of income and expense [abstract]

Summary of Finance Costs


	Year ended December 31,
	2019			2020			2021
	NT$000			NT$000			NT$000
Interest expense
Bank loans		171,840			158,720			116,946
Lease liabilities		14,349			13,442			15,245
Less: Amounts capitalized in qualifying assets		(15,114	)		(9,762	)		(11,193	)

		171,075			162,400			120,998
Finance expense		9,187			9,082			10,186

		180,262			171,482			131,184

Expenses by nature (Tables)

12 Months Ended

Dec. 31, 2021

Summary of Expenses by nature


	Year ended December 31,
	2019		2020		2021
	NT$000		NT$000		NT$000
Raw materials and supplies used		3,575,283		4,708,493		5,518,145
Employee benefit expenses		6,075,773		6,010,227		6,757,888
Depreciation expenses		3,731,914		4,175,519		4,634,112
Others		4,590,720		4,686,218		5,053,088

		17,973,690		19,580,457		21,963,233

Employee benefit expenses (Tables)

12 Months Ended

Dec. 31, 2021

Summary of Employee benefit expenses


	Year ended December 31,
	2019		2020		2021
	NT$000		NT$000		NT$000
Salaries		5,114,790		4,937,591		5,632,219
Directors’ remuneration		26,266		28,229		40,164
Labor and health insurance		422,106		396,796		424,901
Pension		194,173		189,489		200,014
Share-based payments		822		—		—
Other personnel expenses		317,616		458,122		460,590

		6,075,773		6,010,227		6,757,888

For the year of 2020, employees’ compensation and directors’ remuneration recognized were consistent with the amounts resolved in the Board of Directors’ meeting.

Income tax expense (Tables)

12 Months Ended

Dec. 31, 2021

Major Components of Income Tax Expense

(a)

Components of income tax expense:


	Year ended December 31,
	2019			2020			2021
	NT$000			NT$000			NT$000
Current income tax:
Current income tax on profits for the period		408,788			636,876			1,109,752
Income tax on unappropriated retained earnings		74,540			105,665			227,467
Prior year income tax overestimation		(5,016	)		(133,923	)		(184,284	)

Total current income tax		478,312			608,618			1,152,935

Deferred income tax:
Relating to origination and reversal of temporary differences		35,367			(14,237	)		(54,617	)

Income tax expense		513,679			594,381			1,098,318

Deferred Tax Charged to Other Comprehensive Income

(b)

The income tax (charge)/credit relating to components of other comprehensive income are as follows:


	Year ended December 31,
	2019			2020			2021
	NT$000			NT$000			NT$000
Unrealized (loss) gain on valuation of financial assets at fair value through other comprehensive income		(7,016	)		34,794			30,459
Remeasurement of defined benefit obligations		4,183			(10,398	)		(2,999	)

		(2,833	)		24,396			27,460

Reconciliation of Income Tax Expense and Accounting Profit Before Income Tax

Reconciliation of income tax expense and the accounting profit:


	Year ended December 31,
	2019			2020			2021
	NT$000			NT$000			NT$000
Tax calculated based on profit before tax and statutory tax rate		606,917			595,258			1,207,605
Effects from adjustments based on regulation		(162,924	)		26,974			(152,618	)
Temporary difference not recognized as deferred tax assets		(608	)		(4	)		—
Prior year income tax overestimation		(5,016	)		(133,923	)		(184,284	)
Income tax on unappropriated retained earnings		74,540			105,665			227,467
Effect of different tax rates in countries in which the Group operates		770			411			148

Income tax expense		513,679			594,381			1,098,318

Details of Deferred Tax Assets (Liabilities)

The amounts of deferred tax assets or liabilities resulting from temporary differences and investment tax credits are as follows:


	2019
	January 1			Recognized in profit or loss			Recognized in other comprehensive income			December 31
	NT$000			NT$000			NT$000			NT$000
Deferred tax assets
Loss on inventories		7,232			5,468			—			12,700
Property, plant and equipment		64,183			(25,515	)		—			38,668
Provisions		12,396			(6,796	)		—			5,600
Deferred revenue		34,156			(6,506	)		—			27,650
Net defined benefit liability		100,743			(3,948	)		(4,183	)		92,612
Unrealized exchange losses		3,575			13,721			—			17,296
Investment tax credit		4,420			(4,420	)		—			—
Others		11			15			—			26

Total		226,716			(27,981	)		(4,183	)		194,552

Deferred tax liabilities
Property, plant and equipment		(281,594	)		(7,386	)		—			(288,980	)
Financial assets at fair value through other comprehensive income		(27,165	)		—			7,016			(20,149	)

Total		(308,759	)		(7,386	)		7,016			(309,129	)

Information presented on statements of financial position
Deferred tax assets		226,716									194,552

Deferred tax liabilities		(308,759	)								(309,129	)


	2020
	January 1			Recognized in profit or loss			Recognized in other comprehensive income			December 31
	NT$000			NT$000			NT$000			NT$000
Deferred tax assets
Loss on inventories		12,700			3,263			—			15,963
Property, plant and equipment		38,668			(2,267	)		—			36,401
Provisions		5,600			(2,922	)		—			2,678
Deferred revenue		27,650			(6,506	)		—			21,144
Net defined benefit liability		92,612			(4,089	)		10,398			98,921
Unrealized exchange losses		17,296			(7,381	)		—			9,915
Others		26			643			—			669

Total		194,552			(19,259	)		10,398			185,691

Deferred tax liabilities
Property, plant and equipment		(288,980	)		33,496			—			(255,484	)
Financial assets at fair value through other comprehensive income		(20,149	)		—			(34,794	)		(54,943	)

Total		(309,129	)		33,496			(34,794	)		(310,427	)

Information presented on statements of financial position
Deferred tax assets		194,552									185,691

Deferred tax liabilities		(309,129	)								(310,427	)


	2021
	January 1			Recognized in profit or loss			Recognized in other comprehensive income			December 31
	NT$000			NT$000			NT$000			NT$000
Deferred tax assets
Loss on inventories		15,963			8,354			—			24,317
Property, plant and equipment		36,401			235			—			36,636
Provisions		2,678			171			—			2,849
Deferred revenue		21,144			(6,506	)		—			14,638
Net defined benefit liability		98,921			(4,672	)		2,999			97,248
Unrealized exchange losses		9,915			(7,754	)		—			2,161
Others		669			2,080			—			2,749

Total		185,691			(8,092	)		2,999			180,598

Deferred tax liabilities
Property, plant and equipment		(255,484	)		62,797			—			(192,687	)
Financial assets at fair value through other comprehensive income		(54,943	)		—			(30,459	)		(85,402	)
Others		—			(88	)		—			(88	)

Total		(310,427	)		62,709			(30,459	)		(278,177	)

Information presented on statements of financial position
Deferred tax assets		185,691									180,598

Deferred tax liabilities		(310,427	)								(278,177	)

Summary of Deductible Temporary Differences for which No Deferred Tax Asset Is Recognized

The amounts of deductible temporary difference that are not recognized as deferred tax assets are as follows:


	December 31, 2020		December 31, 2021
	NT$000		NT$000
Deductible temporary differences		946,236		371,133

Earnings per share (Tables)

12 Months Ended

Dec. 31, 2021

Income and Share Data Used in Basic and Diluted EPS Computations

Year ended December 31, 2019

Amount

after income
tax

Weighted average
number of ordinary
shares outstanding

Earnings

per share

Basic earnings per share

NT$000

In thousands

NT$

Profit attributable to equity holders of the Company

2,508,574

727,111

3.45

Diluted earnings per share

Assumed conversion of all dilutive potential ordinary shares:

Employees’ compensation

9,879

Restricted shares

126

Profit attributable to equity holders of the Company

2,508,574

737,116

3.40

Year ended December 31, 2020

Amount

after income
tax

Weighted average
number of ordinary
shares outstanding

Earnings

per share

Basic earnings per share

NT$000

In thousands

NT$

Profit attributable to equity holders of the Company

2,378,978

727,240

3.27

Diluted earnings per share

Assumed conversion of all dilutive potential ordinary shares:

Employees’ compensation

9,668

Profit attributable to equity holders of the Company

2,378,978

736,908

3.23

Year ended December 31, 2021

Amount

after income
tax

Weighted average
number of ordinary
shares outstanding

Earnings

per share

Basic earnings per share

NT$000

In thousands

NT$

Profit attributable to equity holders of the Company

4,937,267

727,240

6.79

Diluted earnings per share

Assumed conversion of all dilutive potential ordinary shares:

Employees’ compensation

15,618

Profit attributable to equity holders of the Company

4,937,267

742,858

6.65

Supplementary cash flow information (Tables)

12 Months Ended

Dec. 31, 2021

Partial Cash Paid for Investing Activities

Property, plant and equipment


	Year ended December 31,
	2019			2020			2021
	NT$000			NT$000			NT$000
Purchase of property, plant and equipment		4,896,656			4,133,615			6,552,702
Add: Beginning balance of payable to contractors and equipment suppliers		1,516,735			972,770			1,145,359
Less: Ending balance of payable to contractors and equipment suppliers		(972,770	)		(1,145,359	)		(1,816,555	)

Cash paid during the year		5,440,621			3,961,026			5,881,506

Changes in liabilities from financing activities (Tables)

12 Months Ended

Dec. 31, 2021

Reconciliation of Liabilities Arising from Financing Activities


	2019
	Long-term bank loans (including current portion)			Guarantee deposits		Lease liabilities			Total liabilities from financing activities
	NT$000			NT$000		NT$000			NT$000
January 1		9,789,518			1,092		—			9,790,610
Effects on initial application of IFRS 16		—			—		884,275			884,275

Adjusted balance at January 1		9,789,518			1,092		884,275			10,674,885
Changes in cash flow from financing activities		(756,450	)		3		(48,161	)		(804,608	)
Adjustment to right-of-use assets		—			—		(148,512	)		(148,512	)
Reclassification to payable on equipment from lease liabilities		—			—		(9,000	)		(9,000	)
Amortization of loan fees		8,577			—		—			8,577
Amortization of interest expense		—			—		14,349			14,349

December 31		9,041,645			1,095		692,951			9,735,691


	2020
	Long-term bank loans (including current portion)			Guarantee deposits		Lease liabilities			Total liabilities from financing activities
	NT$000			NT$000		NT$000			NT$000
January 1		9,041,645			1,095		692,951			9,735,691
Changes in cash flow from financing activities		(1,326,857	)		575		(84,928	)		(1,411,210	)
Adjustment to right-of-use assets		—			—		249,030			249,030
Reclassification		—			20,000		—			20,000
Amortization of loan fees		7,581			—		—			7,581
Amortization of interest expense		11,196			—		13,442			24,638

December 31		7,733,565			21,670		870,495			8,625,730


	2021
	Short-term bank loans		Long-term bank loans (including current portion)		Guarantee deposits			Lease liabilities			Total liabilities from financing activities
	NT$000		NT$000		NT$000			NT$000			NT$000
January 1		—		7,733,565		21,670			870,495			8,625,730
Changes in cash flow from financing activities		731,751		1,652,332		(45	)		(289,668	)		2,094,370
Adjustment to right-of-use assets		—		—		—			255,179			255,179
Amortization of loan fees		—		7,646		—			—			7,646
Amortization of interest expense		—		19,822		—			15,245			35,067

December 31		731,751		9,413,365		21,625			851,251			11,017,992

Related party transactions (Tables)

12 Months Ended

Dec. 31, 2021

Summary of Significant Related Party Transactions

Names of related parties and relationship


Name	Relationship
Unimos Shanghai		Associate
JMC		Associate

Key Management Personnel Compensation

Key management personnel compensation


	Year ended December 31,
	2019		2020		2021
	NT$000		NT$000		NT$000
Salaries and other short-term employee benefits		178,713		186,854		243,405
Post-employment compensation		2,049		4,258		2,156

		180,762		191,112		245,561

Pledged assets (Tables)

12 Months Ended

Dec. 31, 2021

Certain Assets Provided as Collateral Mainly for Long-term Bank Loans and Leases

Assets

Purpose

December 31,
2020

December 31,
2021

Carrying
amount

NT$000

Non-current

financial assets at amortized cost

Lease and bank loan

48,319

37,539

Property, plant and equipment, net

- Land

Bank loan

452,738

- Buildings

Bank loan

4,092,287

4,343,556

- Machinery and equipment

Bank loan

6,912,544

8,245,561

11,505,888

13,079,394

Significant contingent liabilities and unrecognized contract commitments (Tables)

12 Months Ended

Dec. 31, 2021

Capital Expenditures that are Contracted for, but not Provided for

Capital expenditures that are contracted for, but not provided for are as follows:


	December 31, 2020		December 31, 2021
	NT$000		NT$000
Property, plant and equipment, net		2,331,041		2,629,129

Capital management (Tables)

12 Months Ended

Dec. 31, 2021

Summary of Group Monitors Capital using Liabilities to Assets Ratio

The liabilities to assets ratio at December 31, 2020 and 2021 were as follows:


	December 31, 2020			December 31, 2021
	NT$000			NT$000
Total liabilities		14,364,975			18,380,369
Total assets		35,080,814			42,522,584

Liabilities to assets ratio		40.95	%		43.22	%

Financial risk management and fair values of financial instruments (Tables)

12 Months Ended

Dec. 31, 2021

Summary of Financial Instruments by Category

(a)

Financial instruments by category


	December 31, 2020		December 31, 2021
	NT$000		NT$000
Financial assets
Financial assets at fair value through profit or loss
Financial assets mandatorily measured at fair value through profit or loss		63,488		359,960
Financial assets at fair value through other comprehensive income
Designation of equity instruments		262,007		384,521
Financial assets at amortized cost
Cash and cash equivalents		4,113,651		5,906,176
Financial assets at amortized cost		254,801		66,778
Notes receivable		599		1,035
Accounts receivable		5,364,156		6,344,246
Other receivables		51,436		86,879
Refundable deposits		21,186		21,278

		10,131,324		13,170,873

Financial liabilities
Financial liabilities at amortized cost
Short-term bank loans		—		731,751
Notes payable		2,899		23
Accounts payable		966,821		1,012,391
Other payables		3,249,403		4,378,439
Long-term bank loans (including current portion)		7,733,565		9,413,365
Lease liabilities (including current portion)		870,495		851,251
Guarantee deposits		21,670		21,625

		12,844,853		16,408,845

Information on Assets and Liabilities Denominated in Foreign Currencies whose Values would be Materially Affected by Exchange Rate Fluctuations

The information on assets and liabilities denominated in foreign currencies whose values would be materially affected by the exchange rate fluctuations is as follows:


	December 31, 2020
	Foreign currency		Exchange rate		Carrying amount (NT$000)
(Foreign currency: functional currency)
Financial assets
Monetary items
US$000		175,840		28.4800		5,007,923
JPY000		137,635		0.2763		38,029
RMB000		6,838		4.3770		29,930
Non-monetary items
JPY000		948,270		0.2763		262,007
RMB000		690,178		4.3770		3,020,908
Financial liabilities
Monetary items
US$000		26,410		28.4800		752,157
JPY000		1,538,241		0.2763		425,016


	December 31, 2021
	Foreign currency		Exchange rate		Carrying amount (NT$000)
(Foreign currency: functional currency)
Financial assets
Monetary items
US$000		188,143		27.6800		5,207,798
JPY000		141,523		0.2405		34,036
RMB000		4,944		4.3440		21,477
Non-monetary items
JPY000		1,598,839		0.2405		384,521
RMB000		827,811		4.3440		3,596,012
Financial liabilities
Monetary items
US$000		53,042		27.6800		1,468,203
JPY000		1,089,668		0.2405		262,005

Details of Exposure to Currency Risk Arising from Recognized Monetary Assets or Liabilities Denominated in a Currency Other Than Functional Currency

Analysis of foreign currency market risk arising from significant foreign exchange variations:


	Year ended December 31, 2019
	Sensitivity analysis
	Change in exchange rate			Effect on profit (loss) (NT$000)		Effect on other comprehensive income (NT$000)
Financial assets
Monetary items
US$000		5	%		282,365		—
JPY000		5	%		3,682		—
RMB000		5	%		1,334		—
Financial liabilities
Monetary items
US$000		5	%		11,793		—
JPY000		5	%		14,261		—


	Year ended December 31, 2020
	Sensitivity analysis
	Change in exchange rate			Effect on profit (loss) (NT$000)		Effect on other comprehensive income (NT$000)
Financial assets
Monetary items
US$000		5	%		250,396		—
JPY000		5	%		1,901		—
RMB000		5	%		1,497		—
Financial liabilities
Monetary items
US$000		5	%		37,608		—
JPY000		5	%		21,251		—


	Year ended December 31, 2021
	Sensitivity analysis
	Change in exchange rate			Effect on profit (loss) (NT$000)		Effect on other comprehensive income (NT$000)
Financial assets
Monetary items
US$000		5	%		260,390		—
JPY000		5	%		1,702		—
RMB000		5	%		1,074		—
Financial liabilities
Monetary items
US$000		5	%		73,410		—
JPY000		5	%		13,103		—

Summary of Loss Rate Methodology

As of December 31, 2020 and 2021 the loss rate methodologies are as follows:


	December 31, 2020
	Contract assets			Accounts receivable (including related parties)			Other receivables (including related parties)
	NT$000			NT$000			NT$000
Expected loss rate		0.030	%		0.030	%		0.030	%
Total carrying amount		389,133			5,365,776			51,446
Loss allowance		(117	)		(1,620	)		(10	)


	December 31, 2021
	Contract assets			Accounts receivable (including related parties)			Other receivables (including related parties)
	NT$000			NT$000			NT$000
Expected loss rate		0.030	%		0.030	%		0.030	%
Total carrying amount		400,375			6,346,156			86,895
Loss allowance		(120	)		(1,910	)		(16	)

Summary of Movements in Relation to Loss Allowance for Contract Assets, Accounts Receivable and Other Receivables

Under the simplified approach, movements in relation to loss allowance for contract assets, accounts receivable, and other receivables are as follows:


	2019
	Contract assets			Accounts receivable (including related parties)			Other receivables (including related parties)
	NT$000			NT$000			NT$000
January 1		(135	)		(2,141	)		(13	)
Provision for impairment loss		—			—			(5	)
Reversal of impairment loss		21			790			—

December 31		(114	)		(1,351	)		(18	)


	2020
	Contract assets			Accounts receivable (including related parties)			Other receivables (including related parties)
	NT$000			NT$000			NT$000
January 1		(114	)		(1,351	)		(18	)
Provision for impairment loss		(3	)		(269	)		—
Reversal of impairment loss		—			—			8

December 31		(117	)		(1,620	)		(10	)


	2021
	Contract assets			Accounts receivable (including related parties)			Other receivables (including related parties)
	NT$000			NT$000			NT$000
January 1		(117	)		(1,620	)		(10	)
Provision for impairment loss		(3	)		(290	)		(6	)

December 31		(120	)		(1,910	)		(16	)

Maturity Profile of Non-derivative Financial Liabilities Based on Contracted Undiscounted Payments


	December 31, 2020
	Within 1 year		1 to 3 years		3 to 5 years		Over 5 years		Total
	NT$000		NT$000		NT$000		NT$000		NT$000
Non-derivative financial liabilities
Long-term bank loans		846,401		3,558,597		2,198,717		1,487,808		8,091,523
Lease liabilities		145,594		160,146		54,689		718,752		1,079,181
Guarantee deposits		—		—		—		21,670		21,670

		991,995		3,718,743		2,253,406		2,228,230		9,192,374


	December 31, 2021
	Within 1 year		1 to 3 years		3 to 5 years		Over 5 years		Total
	NT$000		NT$000		NT$000		NT$000		NT$000
Non-derivative financial liabilities
Short-term bank loans		733,523		—		—		—		733,523
Long-term bank loans		114,953		2,817,662		4,568,521		2,265,350		9,766,486
Lease liabilities		182,186		119,748		54,113		691,764		1,047,811
Guarantee deposits		—		—		—		21,625		21,625

		1,030,662		2,937,410		4,622,634		2,978,739		11,569,445

Summary of Natures of Assets and Liabilities

The related information of natures of the assets and liabilities are as follows:


	December 31, 2020
	Level 1		Level 2		Level 3		Total
	NT$000		NT$000		NT$000		NT$000
Assets
Recurring fair value measurements
Financial assets at fair value through profit or loss
- Listed stocks		53,120		—		—		53,120
- Foreign partnership interests		—		—		10,368		10,368
Financial assets at fair value through other comprehensive income
- Foreign unlisted stocks		—		—		262,007		262,007

		53,120		—		272,375		325,495


	December 31, 2021
	Level 1		Level 2		Level 3		Total
	NT$000		NT$000		NT$000		NT$000
Assets
Recurring fair value measurements
Financial assets at fair value through profit or loss
- Listed stocks		359,960		—		—		359,960
Financial assets at fair value through other comprehensive income
- Foreign unlisted stocks		—		—		384,521		384,521

		359,960		—		384,521		744,481

Summary of Movements of Level 3

(d)

The following table shows the movements of Level 3 for the years ended December 31, 2020 and 2021:


	December 31, 2020
	Debt instruments			Equity instruments		Total
	NT$000			NT$000		NT$000
January 1		11,038			121,808		132,846
Gains or losses recognized in profit or loss
Recorded as non-operating expenses		(670	)		—		(670	)
Gains or losses recognized in other comprehensive income
Recorded as unrealized gains on valuation of financial assets at fair value through other comprehensive income		—			140,199		140,199

December 31		10,368			262,007		272,375


	December 31, 2021
	Debt instruments			Equity instruments		Total
	NT$000			NT$000		NT$000
January 1		10,368			262,007		272,375
Gains or losses recognized in profit or loss
Recorded as non-operating expenses		(941	)		—		(941	)
Gains or losses recognized in other comprehensive income
Recorded as unrealized gains on valuation of financial assets at fair value through other comprehensive income		—			122,514		122,514
Sold in the period		(9,427	)		—		(9,427	)

December 31		—			384,521		384,521

Summary of Qualitative Information and Sensitivity Analysis of Changes in Significant Unobservable Inputs Under Valuation Model Used in Level 3 Fair Value Measurement

(f)

The following is the qualitative information and sensitivity analysis of changes in significant unobservable inputs under valuation model used in Level 3 fair value measurement:

Fair value as of

December 31,
2020

Valuation

technique

Significant

unobservable
input

Range

(weighted
average
method)

Relationship of inputs

to fair value

NT$000

Non-derivative

debt instrument:

Foreign partnership interests

10,368

Discounted cash flow

Discount
rate

0.30

The lower the discount rate, the higher the fair value

Non-derivative

equity instrument:

Foreign unlisted stocks

262,007

Comparable companies

Price to book
ratio
multiple

1.97

The higher the multiple, the higher the fair value

Enterprise
value to
EBITDA
multiple

12.00

The higher the multiple, the higher the fair value

Discount for
lack of
marketability

15.80

The higher the discount for lack of marketability, the lower the fair value

Fair value as of

December 31,
2021

Valuation

technique

Significant

unobservable
input

Range

(weighted

average
method)

Relationship of inputs

to fair value

NT$000

Non-derivative

equity instrument:

Foreign unlisted stocks

384,521

Comparable companies

Price to book
ratio
multiple

3.46

The higher the multiple, the higher the fair value

Enterprise
value to
EBITDA
multiple

9.43

The higher the multiple, the higher the fair value

Discount for
lack of
marketability

15.80

The higher the discount for lack of marketability, the lower the fair value

Summary of Effect of Profit or Loss or of Other Comprehensive Income from Financial Assets Categorized


			December 31, 2020
			Recognized in profit or loss				Recognized in other comprehensive income
	Input	Change	Favorable change		Unfavorable change		Favorable change		Unfavorable change
			NT$000		NT$000		NT$000		NT$000
Financial assets:
Foreign partnership interests	Discount rate	Note		—		—		—		—
Foreign unlisted stocks	Price to book ratio multiple	± 1%		—		—		30		30
	Enterprise value to EBITDA multiple	± 1%		—		—		2,153		2,153
	Discount for lack of marketability	± 1%		—		—		3,142		3,084

				—		—		5,325		5,267


					December 31, 2021
					Recognized in profit or loss				Recognized in other comprehensive income
	Input		Change		Favorable change		Unfavorable change		Favorable change		Unfavorable change
					NT$000		NT$000		NT$000		NT$000
Financial assets:
Foreign unlisted stocks		Price to book ratio multiple		±1%		—		—		46		46
		Enterprise value to EBITDA multiple		±1%		—		—		3,443		3,443
		Discount for lack of marketability		±1%		—		—		4,585		4,585

						—		—		8,074		8,074

Segment Information (Tables)

12 Months Ended

Dec. 31, 2021

Financial Segment Information for Operating Segments

The segment information provided to the chief operating decision maker for the reportable segments is as follows:


	Year ended December 31, 2019
	Testing			Assembly			LCDD			Bumping			Others			Elimination			Total
	NT$000			NT$000			NT$000			NT$000			NT$000			NT$000			NT$000
Revenue
External customers		4,257,800			5,148,877			6,922,205			4,008,999			—			—			20,337,881
Inter-segment		—			—			—			—			32,808			(32,808	)		—

Total revenue		4,257,800			5,148,877			6,922,205			4,008,999			32,808			(32,808	)		20,337,881

Operating profit (loss)		709,142			(227,096	)		1,740,720			232,404			1,931			18			2,457,119

Depreciation expenses		(802,740	)		(521,311	)		(1,796,951	)		(604,553	)		(6,359	)		—			(3,731,914	)

Share of profit (loss) of associates		—			—			—			—			(370,351	)		215,425			(154,926	)

Interest income		—			—			—			—			64,368			—			64,368

Interest expense		—			—			—			—			(171,075	)		—			(171,075	)

Purchase of property, plant and equipment		764,105			548,063			3,077,806			506,635			47			—			4,896,656


	Year ended December 31, 2020
	Testing			Assembly			LCDD			Bumping			Others			Elimination			Total
	NT$000			NT$000			NT$000			NT$000			NT$000			NT$000			NT$000
Revenue
External customers		5,002,730			6,001,964			7,023,003			4,983,684			—			—			23,011,381
Inter-segment		—			—			—			—			39,646			(39,646	)		—

Total revenue		5,002,730			6,001,964			7,023,003			4,983,684			39,646			(39,646	)		23,011,381

Operating profit (loss)		1,333,682			67,730			1,687,986			487,323			(10,230	)		11			3,566,502

Depreciation expenses		(853,829	)		(523,341	)		(2,213,504	)		(578,890	)		(5,955	)		—			(4,175,519	)

Share of profit (loss) of associates		—			—			—			—			(320,578	)		173,249			(147,329	)

Interest income		—			—			—			—			27,778			—			27,778

Interest expense		—			—			—			—			(162,400	)		—			(162,400	)

Purchase of property, plant and equipment		887,204			803,693			2,143,401			298,834			483			—			4,133,615


	Year ended December 31, 2021
	Testing			Assembly			LCDD			Bumping			Others			Elimination			Total
	NT$000			NT$000			NT$000			NT$000			NT$000			NT$000			NT$000
Revenue
External customers		5,899,600			7,963,714			8,211,099			5,325,622			—			—			27,400,035
Inter-segment		—			—			—			—			43,808			(43,808	)		—

Total revenue		5,899,600			7,963,714			8,211,099			5,325,622			43,808			(43,808	)		27,400,035

Operating profit (loss)		1,814,021			857,304			2,336,394			561,642			(6,987	)		15			5,562,389

Depreciation expenses		(921,999	)		(576,138	)		(2,579,150	)		(549,020	)		(7,805	)		—			(4,634,112	)

Share of profit (loss) of associates		—			—			—			—			1,211,177			(585,444	)		625,733

Interest income		—			—			—			—			9,980			—			9,980

Interest expense		—			—			—			—			(120,998	)		—			(120,998	)

Purchase of property, plant and equipment		1,841,359			1,553,475			2,748,697			408,751			420			—			6,552,702

Schedule of information on products and services

Information on products and services


	Year ended December 31,
	2019				2020				2021
	NT$000		%		NT$000		%		NT$000		%
Testing		4,257,800		21		5,002,730		22		5,899,600		22
Assembly		5,148,877		25		6,001,964		26		7,963,714		29
LCDD		6,922,205		34		7,023,003		30		8,211,099		30
Bumping		4,008,999		20		4,983,684		22		5,325,622		19

		20,337,881		100		23,011,381		100		27,400,035		100

Geographic Information of Revenue

Geographical information


	Year ended December 31,
	2019		2020		2021
	NT$000		NT$000		NT$000
Revenue
ROC		15,875,027		18,341,726		21,608,567
Japan		1,905,032		1,291,026		1,768,460
Singapore		1,333,114		1,838,394		1,630,733
PRC		789,496		1,105,535		1,899,362
Others		435,212		434,700		492,913

		20,337,881		23,011,381		27,400,035


	December 31, 2020		December 31, 2021
	NT$000		NT$000
Non-current assets
ROC		18,913,501		21,506,565
PRC		117		86
Others		11,845		6,245

		18,925,463		21,512,896

Net Revenue from Customers Representing at Least 10% of Total Revenue

The information on the major customers which constituted more than 10% of the Group’s total revenue for the years ended December 31, 2019, 2020 and 2021 is as follows:


	Year ended December 31,
	2019				2020				2021
	Amount		%		Amount		%		Amount		%
	NT$000				NT$000				NT$000
Customers
Customer A		4,756,755		23		5,088,544		22		5,681,277		21
Customer M		1,259,269		6		1,674,801		7		2,832,088		10
Customer K		2,419,612		12		2,332,914		10		2,519,631		9
Customer B		1,679,344		8		2,365,945		10		2,484,611		9
Customer C		2,048,260		10		2,143,130		9		2,268,439		8

Financial Statements Schedule: Valuation and Qualifying Accounts (Tables)

12 Months Ended

Dec. 31, 2021

Disclosure Of Details Of Valuation And Qualifying Accounts


	January 1		Additions charged to expense or deduction of revenue		Deduction / Write-offs / Reversal			December 31
	NT$000		NT$000		NT$000			NT$000
Year of 2019 :
Allowance for impairment of property, plant and equipment		317,593		9,938		(134,191	)		193,340
Allowance for impairment of obsolescence and decline in market value of inventories		36,157		27,341		—			63,498
Provision for deficiency compensation		29,352		5,204		(32,558	)		1,998
Sales for allowance		32,627		63,863		(70,490	)		26,000
Year of 2020 :
Allowance for impairment of property, plant and equipment		193,340		—		(11,338	)		182,002
Allowance for impairment of obsolescence and decline in market value of inventories		63,498		16,317		—			79,815
Provision for deficiency compensation		1,998		4,358		(2,893	)		3,463
Sales for allowance		26,000		21,916		(38,052	)		9,864


	January 1		Additions charged to expense or deduction of revenue		Deduction / Write-offs / Reversal			December 31
	NT$000		NT$000		NT$000			NT$000
Year of 2021 :
Allowance for impairment of property, plant and equipment		182,002		4,843		(3,666	)		183,179
Allowance for impairment of obsolescence and decline in market value of inventories		79,815		41,771		—			121,586
Provision for deficiency compensation		3,463		11,898		(11,080	)		4,281
Sales for allowance		9,864		34,744		(34,759	)		9,849

For movements in loss allowance for contract assets, accounts receivable, and other receivables, please refer to Note 43.

The authorization of the consolidated financial statements - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2021
Text block [abstract]
Date of authorization of financial statements by Board of directors	Apr. 14, 2022

Summary of Significant Accounting Policies - Summary of Ownership Interests in Subsidiaries (Detail)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
ChipMOS U.S.A., Inc. [member]
Disclosure of joint ventures [line items]
Name of investor	The Company	The Company
Main businesses	Marketing of semiconductors and electronic related products	Marketing of semiconductors and electronic related products
Location	San Jose, USA	San Jose, USA
Percentage of Ownership (%)	100.00%	100.00%
ChipMOS TECHNOLOGIES (BVI) LTD. [member]
Disclosure of joint ventures [line items]
Name of investor	The Company	The Company
Main businesses	Holding company	Holding company
Location	British Virgin Islands	British Virgin Islands
Percentage of Ownership (%)	100.00%	100.00%
ChipMOS SEMICONDUCTORS (Shanghai) LTD. [Member]
Disclosure of joint ventures [line items]
Name of investor	ChipMOS BVI	ChipMOS BVI
Main businesses	Marketing of semiconductors and electronic related products	Marketing of semiconductors and electronic related products
Location	Shanghai, People’s Republic of China (“PRC”)	Shanghai, People’s Republic of China (“PRC”)
Percentage of Ownership (%)	100.00%	100.00%

Summary of Significant Accounting Policies - Estimated Useful Life for Depreciation of Individual Assets (Detail)	12 Months Ended
	Dec. 31, 2021
Buildings [member] \| Bottom of range [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Estimated useful life of individual assets	5 years
Buildings [member] \| Top of range [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Estimated useful life of individual assets	51 years
Machinery and equipment [member] \| Bottom of range [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Estimated useful life of individual assets	2 years
Machinery and equipment [member] \| Top of range [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Estimated useful life of individual assets	8 years
Tools [member] \| Bottom of range [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Estimated useful life of individual assets	2 years
Tools [member] \| Top of range [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Estimated useful life of individual assets	4 years
Other equipment [member] \| Bottom of range [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Estimated useful life of individual assets	2 years
Other equipment [member] \| Top of range [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Estimated useful life of individual assets	6 years

Translation into U.S. Dollar Amounts - Additional Information (Detail)	Dec. 31, 2021
Foreign exchange rates [abstract]
Foreign exchange rate from New Taiwan dollars to U.S. dollars at the noon buying rate in the City of New York for cable transfers as certified for customs purposes by the Federal Reserve Bank of New York	27.74

Cash and Cash Equivalents - Summary of Cash and Cash Equivalents (Detail) $ in Thousands, $ in Thousands	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)
Cash and cash equivalents [abstract]
Cash on hand and petty cash	$ 450		$ 470
Checking accounts and demand deposits	2,683,977		2,609,421
Time deposits	3,221,749		1,503,760
Cash and cash equivalents	$ 5,906,176	$ 212,912	$ 4,113,651

Financial Assets at Fair Value Through Profit or Loss - Summary of Financial Assets at Fair Value Through Profit or Loss (Detail) $ in Thousands, $ in Thousands	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)
Financial Assets At Fair Value Through Profit Or Loss [line items]
Current financial assets mandatorily measured at fair value through profit or loss	$ 359,960	$ 12,976	$ 53,120
Non-current financial assets mandatorily measured at fair value through profit or loss	0		10,368
Foreign partnership interests [member]
Financial Assets At Fair Value Through Profit Or Loss [line items]
Non-current financial assets mandatorily measured at fair value through profit or loss	0		10,940
Listed stocks [member]
Financial Assets At Fair Value Through Profit Or Loss [line items]
Current financial assets mandatorily measured at fair value through profit or loss	339,679		46,512
Valuation adjustments [member]
Financial Assets At Fair Value Through Profit Or Loss [line items]
Current financial assets mandatorily measured at fair value through profit or loss	20,281		6,608
Non-current financial assets mandatorily measured at fair value through profit or loss	$ 0		$ (572)

Financial Assets at Fair Value Through Profit or Loss - Summary of Amounts recognized in Profit or Loss in Relation to Financial Assets at Fair Value Through Profit or Loss (Detail) $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)	Dec. 31, 2019 TWD ($)
Financial Assets At Fair Value Through Profit Or Loss [line items]
Financial assets mandatorily measured at fair value through profit or loss	$ 15,262	$ 550	$ 24,015	$ 1,317
Foreign partnership interests [member]
Financial Assets At Fair Value Through Profit Or Loss [line items]
Financial assets mandatorily measured at fair value through profit or loss	(941)		(670)	(433)
Beneficiary certificates [member]
Financial Assets At Fair Value Through Profit Or Loss [line items]
Financial assets mandatorily measured at fair value through profit or loss	2,530		18,077	1,750
Listed stocks [member]
Financial Assets At Fair Value Through Profit Or Loss [line items]
Financial assets mandatorily measured at fair value through profit or loss	$ 13,673		$ 6,608	$ 0

Financial Assets at Amortized Cost - Summary of Financial Assets at Amortized Cost (Detail) - TWD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Financial Instruments At Amortised Cost Category[abstract]
Time deposits	$ 29,239	$ 206,482
Restricted bank deposits	37,539	48,319
Interest income	$ 1,187	$ 2,206	$ 4,467

Accounts receivable - Summary of Accounts and notes receivable (Detail) $ in Thousands, $ in Thousands	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)	Jan. 01, 2020 TWD ($)
Disclosure of financial assets [Line Items]
Accounts receivable	$ 6,344,246	$ 228,704	$ 5,364,156
Accounts receivable [member]
Disclosure of financial assets [Line Items]
Accounts receivable	6,346,156		5,365,776	$ 4,452,904
Loss allowance [member]
Disclosure of financial assets [Line Items]
Accounts receivable	$ (1,910)		$ (1,620)

Accounts receivable - Additional Information (Detail) $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)	Jan. 01, 2020 TWD ($)
Disclosure of financial assets [Line Items]
Accounts receivable from contract with customers	$ 6,344,246	$ 228,704	$ 5,364,156
Accounts receivable [member]
Disclosure of financial assets [Line Items]
Accounts receivable from contract with customers	$ 6,346,156		$ 5,365,776	$ 4,452,904
Bottom of range [member]
Disclosure of financial assets [Line Items]
Credit term granted to customers	30 days
Top of range [member]
Disclosure of financial assets [Line Items]
Credit term granted to customers	90 days

Accounts receivable - Aging of Accounts Receivable which are Past Due but not Impaired (Detail) $ in Thousands, $ in Thousands	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)	Jan. 01, 2020 TWD ($)
Disclosure of financial assets [Line Items]
Accounts receivable	$ 6,344,246	$ 228,704	$ 5,364,156
Accounts receivable [member]
Disclosure of financial assets [Line Items]
Accounts receivable	6,346,156		5,365,776	$ 4,452,904
Accounts receivable [member] \| Current [member]
Disclosure of financial assets [Line Items]
Accounts receivable	6,327,791		5,272,208
Accounts receivable [member] \| Within 1 month [member]
Disclosure of financial assets [Line Items]
Accounts receivable	$ 18,365		$ 93,568

Inventories - Summary of Inventories (Detail) - TWD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Disclosure of inventories [Line Items]
Raw materials	$ 3,207,177	$ 2,102,075
Gross carrying amount [member]
Disclosure of inventories [Line Items]
Raw materials	3,328,763	2,181,890
Allowance for impairment losses [member]
Disclosure of inventories [Line Items]
Raw materials	$ (121,586)	$ (79,815)

Inventories - Cost of Inventories Recognized as an Expense (Detail) $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)	Dec. 31, 2019 TWD ($)
Analysis of income and expense [abstract]
Cost of revenue	$ 20,103,735		$ 17,957,568	$ 16,372,032
Loss on abandonment	552		5,323	12,369
Allowance for inventory valuation and obsolescence loss	41,770		16,317	27,341
Cost of revenue	$ 20,146,057	$ 726,246	$ 17,979,208	$ 16,411,742

Non-current Financial Assets at Fair Value Through Other Comprehensive Income - Summary of Non-current Financial Assets at Fair Value Through Other Comprehensive Income (Detail) - TWD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Financial assets at fair value through other comprehensive income [line items]
Designation of equity instruments	$ 384,521	$ 262,007
Foreign unlisted stocks [member]
Financial assets at fair value through other comprehensive income [line items]
Designation of equity instruments	38,534	38,534
Valuation adjustments [member]
Financial assets at fair value through other comprehensive income [line items]
Designation of equity instruments	$ 345,987	$ 223,473

Non-current Financial Assets at Fair Value Through Other Comprehensive Income - Additional Information (Detail)	Dec. 31, 2021 TWD ($)
Financial assets at fair value through other comprehensive income [abstract]
Financial assets at fair value through other comprehensive income were pledged	$ 0

Non-current Financial Assets at Fair Value Through Other Comprehensive Income - Summary Amounts recognized in other comprehensive income in relation to the financial assets at fair value through other comprehensive income (Detail) $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)	Dec. 31, 2019 TWD ($)
Financial assets at fair value through other comprehensive income [abstract]
Foreign unlisted stocks	$ 122,514	$ 4,416	$ 140,199	$ (52,549)

Investments accounted for using equity method - Details of Investment in Associates (Detail) - TWD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Disclosure of associates [line items]
Carrying amount	$ 3,900,449	$ 3,271,677
JMC ELECTRONICS CO., LTD. [member]
Disclosure of associates [line items]
Carrying amount	304,437	250,769
Unimos Shanghai [member]
Disclosure of associates [line items]
Carrying amount	$ 3,596,012	$ 3,020,908

Investments accounted for using equity method - Additional Information (Detail) - TWD ($) $ in Thousands		12 Months Ended
	Apr. 02, 2019	Dec. 31, 2019	Dec. 31, 2021	Dec. 31, 2020
Disclosure of associates [line items]
Cash consideration from disposals of investment in associates		$ 1,180,179
Gain on disposal of investment in associates		$ 973,609
Carrying amount of investment in associates			$ 3,900,449	$ 3,271,677
Individually Immaterial Associates [member]
Disclosure of associates [line items]
Carrying amount of investment in associates			3,900,449	3,271,677
JMC ELECTRONICS CO., LTD. [member]
Disclosure of associates [line items]
Investment in associates at fair value			468,950	454,010
Number of common shares disposed	9,100,000
Percentage of ownership interest in associate	10.00%
Cash consideration from disposals of investment in associates	$ 1,180,179
Gain on disposal of investment in associates	$ 973,609
Carrying amount of investment in associates			$ 304,437	$ 250,769

Investments accounted for using equity method - Summarized Financial Information for Investment in Material Associates (Detail) $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)	Dec. 31, 2019 TWD ($)
Disclosure of associates [line items]
Other comprehensive income, net of income tax	$ 84,203	$ 3,035	$ 115,308	$ (127,266)
Total comprehensive income for the year	5,021,470	$ 181,019	2,494,286	2,381,308
Individually Immaterial Associates [member]
Disclosure of associates [line items]
(Loss) profit for the year from continuing operations	625,733		(147,329)	(154,926)
Other comprehensive income, net of income tax	28,843		23,143	5,732
Total comprehensive income for the year	$ 654,576		$ (124,186)	$ (149,194)

The amount of change in equity resulting from transactions and other events, other than those changes resulting from transactions with owners in their capacity as owners.

Property, Plant and Equipment, Net - Summary of Property, Plant and Equipment, Net (Detail) $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)	Dec. 31, 2019 TWD ($)
Disclosure of detailed information about property, plant and equipment [Line Items]
Beginning Balance	$ 17,994,686		$ 17,979,444	$ 16,819,621
Effects on initial application of IFRS 16				(31,904)
Adjusted Balance On Property Plant And Equipment				16,787,717
Additions	6,552,702		4,133,615	4,896,656
Disposals	(76,375)		(19,358)	(25,785)
Reclassifications	0		0	26,618
Depreciation expenses	(4,355,032)		(4,098,993)	(3,695,815)
Impairment losses	(4,843)			(9,938)
Exchange adjustments	(17)		(22)	(9)
Ending Balance	20,111,121	$ 724,986	17,994,686	17,979,444
Land [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Beginning Balance	452,738		452,738	452,738
Adjusted Balance On Property Plant And Equipment				452,738
Additions	0		0	0
Disposals	0		0	0
Reclassifications	0		0	0
Depreciation expenses	0		0	0
Ending Balance	452,738		452,738	452,738
Buildings [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Beginning Balance	4,092,286		4,095,929	3,908,731
Adjusted Balance On Property Plant And Equipment				3,908,731
Additions	1,345		132,572	116,238
Disposals	0		0	0
Reclassifications	673,208		258,421	455,792
Depreciation expenses	(423,283)		(394,636)	(384,832)
Ending Balance	4,343,556		4,092,286	4,095,929
Machinery and equipment [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Beginning Balance	11,348,297		11,163,121	10,232,093
Adjusted Balance On Property Plant And Equipment				10,232,093
Additions	11,829		592,565	2,334,358
Disposals	(66,873)		(8,940)	(16,033)
Reclassifications	4,890,400		2,336,238	1,111,715
Depreciation expenses	(2,896,612)		(2,734,667)	(2,489,070)
Impairment losses	(4,843)			(9,938)
Exchange adjustments	(13)		(20)	(4)
Ending Balance	13,282,185		11,348,297	11,163,121
Tools [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Beginning Balance	952,361		896,476	742,179
Adjusted Balance On Property Plant And Equipment				742,179
Additions	407		409,832	781,465
Disposals	(9,502)		(3,121)	(9,336)
Reclassifications	690,346		398,798	7,880
Depreciation expenses	(795,622)		(749,624)	(625,712)
Ending Balance	837,990		952,361	896,476
Other [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Beginning Balance	509,397		434,791	413,988
Effects on initial application of IFRS 16				(31,904)
Adjusted Balance On Property Plant And Equipment				382,084
Additions	189		142,776	224,287
Disposals	0		(7,297)	(416)
Reclassifications	241,656		159,195	25,042
Depreciation expenses	(239,515)		(220,066)	(196,201)
Exchange adjustments	(4)		(2)	(5)
Ending Balance	511,723		509,397	434,791
Construction in progress and equipment to be inspected [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Beginning Balance	639,607		936,389	1,069,892
Adjusted Balance On Property Plant And Equipment				1,069,892
Additions	6,538,932		2,855,870	1,440,308
Disposals	0		0	0
Reclassifications	(6,495,610)		(3,152,652)	(1,573,811)
Depreciation expenses	0		0	0
Ending Balance	682,929		639,607	936,389
Gross carrying amount [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Beginning Balance	73,187,794		70,401,687	67,064,936
Ending Balance	78,108,945		73,187,794	70,401,687
Gross carrying amount [member] \| Land [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Beginning Balance	452,738		452,738	452,738
Ending Balance	452,738		452,738	452,738
Gross carrying amount [member] \| Buildings [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Beginning Balance	11,212,129		10,821,972	10,254,531
Ending Balance	11,877,419		11,212,129	10,821,972
Gross carrying amount [member] \| Machinery and equipment [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Beginning Balance	53,246,474		51,244,512	48,274,171
Ending Balance	57,176,339		53,246,474	51,244,512
Gross carrying amount [member] \| Tools [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Beginning Balance	5,451,547		5,008,321	4,402,711
Ending Balance	5,574,316		5,451,547	5,008,321
Gross carrying amount [member] \| Other [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Beginning Balance	2,185,299		1,937,755	2,610,893
Ending Balance	2,345,204		2,185,299	1,937,755
Gross carrying amount [member] \| Construction in progress and equipment to be inspected [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Beginning Balance	639,607		936,389	1,069,892
Ending Balance	682,929		639,607	936,389
Accumulated depreciation and impairment [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Beginning Balance	(55,193,108)		(52,422,243)	(50,245,315)
Ending Balance	(57,997,824)		(55,193,108)	(52,422,243)
Accumulated depreciation and impairment [member] \| Land [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Beginning Balance	0		0	0
Ending Balance	0		0	0
Accumulated depreciation and impairment [member] \| Buildings [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Beginning Balance	(7,119,843)		(6,726,043)	(6,345,800)
Ending Balance	(7,533,863)		(7,119,843)	(6,726,043)
Accumulated depreciation and impairment [member] \| Machinery and equipment [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Beginning Balance	(41,898,177)		(40,081,391)	(38,042,078)
Ending Balance	(43,894,154)		(41,898,177)	(40,081,391)
Accumulated depreciation and impairment [member] \| Tools [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Beginning Balance	(4,499,186)		(4,111,845)	(3,660,532)
Ending Balance	(4,736,326)		(4,499,186)	(4,111,845)
Accumulated depreciation and impairment [member] \| Other [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Beginning Balance	(1,675,902)		(1,502,964)	(2,196,905)
Ending Balance	(1,833,481)		(1,675,902)	(1,502,964)
Accumulated depreciation and impairment [member] \| Construction in progress and equipment to be inspected [member]
Disclosure of detailed information about property, plant and equipment [Line Items]
Beginning Balance	0		0	0
Ending Balance	$ 0		$ 0	$ 0

Property, Plant and Equipment, Net - Capitalization Interest and Capitalization Interest Rate Applied Related to Property, Plant and Equipment (Detail) - TWD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of detailed information about property, plant and equipment [abstract]
Amount of interest capitalized	$ 11,193	$ 9,762	$ 15,114
Range of the interest rates for capitalization	1.1358%	1.4909%	1.7822%

Leasing arrangements - leasee - summary of carrying amount of right-of-use assets and the depreciation expenses (Detail) $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 TWD ($)	Dec. 31, 2020 TWD ($)	Dec. 31, 2019 TWD ($)	Dec. 31, 2021 USD ($)
Disclosure of quantitative information about right-of-use assets [line items]
Carrying amount	$ 835,805	$ 859,069		$ 30,130
Depreciation expenses	279,080	76,526	$ 36,099
Land [member]
Disclosure of quantitative information about right-of-use assets [line items]
Carrying amount	616,458	636,261
Depreciation expenses	20,486	20,938	22,657
Buildings [member]
Disclosure of quantitative information about right-of-use assets [line items]
Carrying amount	10,946	19,044
Depreciation expenses	9,870	7,819	7,113
Machinery and equipment [member]
Disclosure of quantitative information about right-of-use assets [line items]
Carrying amount	204,484	203,249
Depreciation expenses	247,090	46,225	4,520
Others [member]
Disclosure of quantitative information about right-of-use assets [line items]
Carrying amount	3,917	515
Depreciation expenses	$ 1,634	$ 1,544	$ 1,809

Leasing arrangements - leasee - Summary of profit and loss accounts relating to lease contracts (Detail) - TWD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Items affecting profit or loss
Interest expense on lease liabilities	$ 15,245	$ 13,442	$ 14,349
Expense on short-term lease contracts	$ 143,791	$ 202,782	$ 230,589

Leasing arrangements - leasee - Additional Information (Detail) - TWD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement [line items]
Additions to right of use asset	$ 433,768	$ 261,798
Payments of lease liabilities	$ 448,290	$ 274,727	$ 273,709
Top of range [member]
Statement [line items]
Lease term	30 years
Bottom of range [member]
Statement [line items]
Lease term	1 year

Short-term Bank Loans - Summary of Short-term Bank Loans (Detail) - Short-term borrowings [member] $ in Thousands, $ in Thousands	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)	Dec. 31, 2020 USD ($)
Disclosure of detailed information about borrowings [Line Items]
Unsecured bank loans	$ 731,751
Undrawn borrowing facilities	$ 2,918,249	$ 85,025	$ 3,251,000	$ 90,000
Bottom of range [member]
Disclosure of detailed information about borrowings [Line Items]
Interest rate range	0.6604%	0.6604%
Top of range [member]
Disclosure of detailed information about borrowings [Line Items]
Interest rate range	0.7394%	0.7394%

Accounts payable - Summary of Accounts Payable (Detail) - TWD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Statement [LineItems]
Trade and other payables	$ 1,012,391	$ 966,821
Accounts payable [Member]
Statement [LineItems]
Trade and other payables	765,403	766,805
Estimated accounts payable [Member]
Statement [LineItems]
Trade and other payables	$ 246,988	$ 200,016

Other Payables - Summary of Other Payables (Detail) $ in Thousands, $ in Thousands	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)
Trade and other current payables [abstract]
Payables to contractors and equipment suppliers	$ 1,816,555		$ 1,145,359
Salaries and bonuses payable	829,762		788,720
Employees' compensation payable	673,387		332,080
Directors' remuneration payable	25,690		16,604
Pension payable	16,600		15,159
Interest payable	3,277		1,958
Other expense payable	1,013,168		949,523
Other payables	$ 4,378,439	$ 157,838	$ 3,249,403

Long-term Bank Loans - Summary of Long-term Bank Loans (Detail) $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 TWD ($)	Dec. 31, 2020 TWD ($)	Dec. 31, 2021 USD ($)
Disclosure of detailed information about borrowings [Line Items]
Bank loans	$ 9,413,365	$ 7,733,565
Less:Fee on syndicated bank loan	(10,026)	(17,223)
Less: Unamortized interest on government granted bank loans	(93,740)	(64,212)
Less: Current portion (fee included)	(46,826)	(748,353)	$ (1,688)
Syndicated bank loans, excluding current portion	9,366,539	6,985,212	$ 337,655
Long-term bank loans [Member]
Disclosure of detailed information about borrowings [Line Items]
Unused credit lines of long-term bank loan	$ 8,776,868	$ 11,239,000
Gross carrying amount [member] \| Minimum [Member]
Disclosure of detailed information about borrowings [Line Items]
Interest rate range	0.45%	0.65%	0.45%
Gross carrying amount [member] \| Maximum [Member]
Disclosure of detailed information about borrowings [Line Items]
Interest rate range	1.7895%	1.7895%	1.7895%
Gross carrying amount [member] \| Syndicated bank loans repayable from November 2018 to May 2023 [member]
Disclosure of detailed information about borrowings [Line Items]
Bank loans	$ 54,000	$ 3,310,000
Period and payment term	Borrowing period is from May 30, 2018 to May 30, 2023; interest is repayable monthly; principal is repayable semi-annually from November 30, 2018
Gross carrying amount [member] \| Government granted bank loans from March 2020 To November 2031 [Member]
Disclosure of detailed information about borrowings [Line Items]
Bank loans	$ 9,463,131	$ 4,505,000
Period and payment term	Borrowing period is from March 11, 2020 to November 15, 2031; interest is repayable monthly; principal is repayable monthly from March 15, 2023

Long-term Bank Loans - Additional Information (Detail) $ in Millions		23 Months Ended
	May 15, 2018 TWD ($) Bank	Nov. 30, 2021 TWD ($)
Maximum [Member]
Disclosure of detailed information about borrowings [Line Items]
Maturity of loan		ten years
Minimum [Member]
Disclosure of detailed information about borrowings [Line Items]
Maturity of loan		seven years
Syndicated loan [member]
Disclosure of detailed information about borrowings [Line Items]
Number of banks in syndicate \| Bank	11
Principal amount of loan	$ 12,000
Maturity of loan	five years
Government granted bank loans [Member]
Disclosure of detailed information about borrowings [Line Items]
Principal amount of loan		$ 14,640

Pensions - Additional Information (Detail) $ in Thousands	12 Months Ended
Pensions - Additional Information (Detail) $ in Thousands	Dec. 31, 2021 TWD ($) Unit	Dec. 31, 2020 TWD ($)	Dec. 31, 2019 TWD ($)
Disclosure of defined benefit plans [Line Items]
Weighted average duration of defined benefit obligation	12 years 2 months 12 days
ChipMOS Shanghai [Member]
Disclosure of defined benefit plans [Line Items]
Employer contribution percentage	16.00%	16.00%
Pension costs under defined contribution pension plans \| $	$ 209	$ 0
Defined benefit pension plan [Member]
Disclosure of defined benefit plans [Line Items]
Number of units accrued in first tranche	2
Duration of first tranche	first 15 years
Number of units accrued in second tranche	1
Duration of second tranche	Thereafter 15 years
Maximum number of units accruable under the pension plan	45
Benefit measurement period	6 months
Employer contribution percentage	2.00%
Defined contribution pension plan [member]
Disclosure of defined benefit plans [Line Items]
Employer contribution percentage	6.00%
Pension costs under defined contribution pension plans \| $	$ 197,076	$ 184,562	$ 187,502

Pensions - Defined Benefit Plans Amounts Recognized in Statements of Financial Position (Detail) - TWD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Surplus (deficit) in plan [abstract]
Present value of defined benefit obligations	$ (959,677)	$ (943,391)
Fair value of plan assets	456,389	431,740
Net defined benefit liability	$ (503,288)	$ (511,651)	$ (480,107)	$ (520,765)

Pensions - Movements in Net Defined Benefit Liability (Detail) - TWD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of net defined benefit liability (asset) [Line Items]
Beginning balance	$ (511,651)	$ (480,107)	$ (520,765)
Current service cost	(237)	(263)	(332)
Interest (expense) income	(2,492)	(4,664)	(6,339)
Total	(514,380)	(485,034)	(527,436)
Return on plan assets (excluding amounts included in interest income or expense)	5,613	12,568	12,601
Impact on changes in demographic assumptions	(20,022)
Financial assumption movement effect	23,757	(57,180)	(27,993)
Experience adjustments	(24,347)	(7,378)	36,308
Gain (loss) on remeasurement, net defined benefit liability (asset)	(14,999)	(51,990)	20,916
Pension fund contribution	26,091	25,373	26,413
Ending balance	(503,288)	(511,651)	(480,107)
Present Value of Defined Benefit Obligation [member]
Disclosure of net defined benefit liability (asset) [Line Items]
Beginning balance	(943,391)	(901,159)	(910,081)
Current service cost	(237)	(263)	(332)
Interest (expense) income	(4,629)	(8,835)	(11,170)
Total	(948,257)	(910,257)	(921,583)
Impact on changes in demographic assumptions	(20,022)
Financial assumption movement effect	23,757	(57,180)	(27,993)
Experience adjustments	(24,347)	(7,378)	36,308
Gain (loss) on remeasurement, net defined benefit liability (asset)	(20,612)	(64,558)	8,315
Paid pension	9,192	31,424	12,109
Ending balance	(959,677)	(943,391)	(901,159)
Fair Value of Plan Assets [member]
Disclosure of net defined benefit liability (asset) [Line Items]
Beginning balance	431,740	421,052	389,316
Interest (expense) income	2,137	4,171	4,831
Total	433,877	425,223	394,147
Return on plan assets (excluding amounts included in interest income or expense)	5,613	12,568	12,601
Gain (loss) on remeasurement, net defined benefit liability (asset)	5,613	12,568	12,601
Pension fund contribution	26,091	25,373	26,413
Paid pension	(9,192)	(31,424)	(12,109)
Ending balance	$ 456,389	$ 431,740	$ 421,052

Pensions - Principal Actuarial Assumptions Used and Sensitivity Analysis of Present Value of Defined Benefit Obligation Effected by Changes of Principal Actuarial Assumptions (Detail)	Dec. 31, 2021	Dec. 31, 2020
Disclosure of sensitivity analysis for actuarial assumptions [abstract]
Discount rate	0.70%	0.50%
Future salary increases	3.50%	3.50%

Pensions - Sensitivity Analysis of Present Value of Defined Benefit Obligations Effected by Changes of Significant Actuarial Assumptions (Detail) - TWD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Actuarial assumption of discount rates [member]
Disclosure of sensitivity analysis for actuarial assumptions [Line Items]
Percentage increase in assumption	0.25%	0.25%
Effect on present value of defined benefit obligations due to increase in assumption	$ (28,574)	$ (29,114)
Percentage decrease in assumption	0.25%	0.25%
Effect on present value of defined benefit obligations due to decrease in assumption	$ 29,825	$ 30,434
Actuarial assumption of expected rates of salary increases [member]
Disclosure of sensitivity analysis for actuarial assumptions [Line Items]
Percentage increase in assumption	0.25%	0.25%
Effect on present value of defined benefit obligations due to increase in assumption	$ 28,941	$ 29,471
Percentage decrease in assumption	0.25%	0.25%
Effect on present value of defined benefit obligations due to decrease in assumption	$ (27,893)	$ (28,365)

Pensions - Analysis of Timing of the Future Pension Payment (Detail) $ in Thousands	Dec. 31, 2021 TWD ($)
Disclosure of net defined benefit liability (asset) [Line Items]
Defined benefit plan expected future pension payments	$ 378,912
Within 1 year [member]
Disclosure of net defined benefit liability (asset) [Line Items]
Defined benefit plan expected future pension payments	36,762
1-2 years [member]
Disclosure of net defined benefit liability (asset) [Line Items]
Defined benefit plan expected future pension payments	36,346
2-5 years [member]
Disclosure of net defined benefit liability (asset) [Line Items]
Defined benefit plan expected future pension payments	126,806
5-10 years [member]
Disclosure of net defined benefit liability (asset) [Line Items]
Defined benefit plan expected future pension payments	$ 178,998

Share-based Payments - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2019 TWD ($)
Disclosure of terms and conditions of share-based payment arrangement [Line Items]
Compensation expenses	$ 822
Restricted shares award agreement [member]
Disclosure of terms and conditions of share-based payment arrangement [Line Items]
Restricted shares outstanding shares	0

Share-based Payments - Issuance of Restricted Shares (Detail) shares in Thousands	May 10, 2016 shares $ / shares	Jul. 21, 2015 shares $ / shares	Dec. 31, 2019
Disclosure of share based payments other than equity instrument [line items]
Grant date	May 10, 2016	July 21, 2015
Restricted shares award agreement [member]
Disclosure of share based payments other than equity instrument [line items]
Number of shares			0
Restricted shares award agreement [member] \| July 21, 2015 [member]
Disclosure of share based payments other than equity instrument [line items]
Type of arrangement		Restricted shares award agreement
Share price on grant date \| $ / shares		$ 36.1
Number of shares \| shares		15,752
Contract period		3 years
Vesting condition		Meet service and performance conditions
Restricted shares award agreement [member] \| May 10, 2016 [member]
Disclosure of share based payments other than equity instrument [line items]
Type of arrangement	Restricted shares award agreement
Share price on grant date \| $ / shares	$ 30.6
Number of shares \| shares	1,548
Contract period	3 years
Vesting condition	Meet service and performance conditions

Capital stock - Additional Information (Detail) $ / shares in Units, $ in Thousands, $ in Thousands			12 Months Ended
	Aug. 06, 2019 TWD ($) shares	Mar. 07, 2019 TWD ($) shares	Dec. 31, 2021 TWD ($) $ / shares shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 TWD ($)
Disclosure of classes of share capital [line items]
Ordinary shares par value \| $ / shares			$ 10
Number of shares outstanding			727,240,000	727,240,000
Authorised capital \| $			$ 9,700,000
Number of shares authorized			970,000,000	970,000,000
Paid in capital			$ 7,272,401	$ 262,163	$ 7,272,401
Approval for number of treasury stock cancelled	25,570,000	25,570,000
Cancellation of treasury stock \| $	$ 962,503	$ 962,503
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Number of shares outstanding			91,725,000	91,725,000
American depositary shares [member]
Disclosure of classes of share capital [line items]
Number of shares represented by each unit of ADS			20
Number of shares outstanding			4,586,252	4,586,252

Capital stock - Movement of Ordinary Shares Issued (Detail) - Ordinary shares [member] - shares shares in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of classes of share capital [line items]
Beginning balance	727,240	727,240	727,265
Restricted shares – cancelled			(25)
Ending balance	727,240	727,240	727,240

Capital Surplus - Details of Capital Surplus (Detail) $ in Thousands, $ in Thousands			12 Months Ended
	Aug. 06, 2019 TWD ($)	Mar. 07, 2019 TWD ($)	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)	Dec. 31, 2019 TWD ($)
Statement [LineItems]
Beginning balance			$ 6,050,787
Share-based payments						$ 822
Cancellation of treasury stock	$ 962,503	$ 962,503
Changes in associates accounted for using equity method			4,834
Ending balance			6,055,621	$ 218,299	$ 6,050,787
Capital surplus [member]
Statement [LineItems]
Beginning balance			6,050,787		6,050,787	6,263,553
Share-based payments						(412)
Cancellation of treasury stock						(212,354)
Changes in associates accounted for using equity method			4,834
Ending balance			6,055,621		6,050,787	6,050,787
Capital surplus [member] \| Share premium [member]
Statement [LineItems]
Beginning balance			6,043,483		5,674,242	5,873,743
Cancellation of treasury stock						(199,501)
Reclassifications					369,241
Ending balance			6,043,483		6,043,483	5,674,242
Capital surplus [member] \| Employee restricted shares [member]
Statement [LineItems]
Beginning balance					369,241	382,506
Share-based payments						(412)
Cancellation of treasury stock						(12,853)
Reclassifications					(369,241)
Ending balance						369,241
Capital surplus [member] \| Others [member]
Statement [LineItems]
Beginning balance			7,304		7,304	7,304
Changes in associates accounted for using equity method			4,834
Ending balance			$ 12,138		$ 7,304	$ 7,304

Retained Earnings - Details of Retained Earnings (Detail) - TWD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure of analysis of other comprehensive income by item [line items]
Cash dividend, cash distribution per share	$ 2.20	$ 1.80	$ 1.20
Legal reserve [member]
Disclosure of analysis of other comprehensive income by item [line items]
Appropriation of retained earnings	$ 232,611	$ 258,416	$ 110,308
Special Reserve [Member]
Disclosure of analysis of other comprehensive income by item [line items]
Appropriation of retained earnings	(19,802)	19,802
Cash Dividend [Member]
Disclosure of analysis of other comprehensive income by item [line items]
Appropriation of retained earnings	$ 1,599,928	$ 1,309,032	$ 872,718

Other equity interest - Summary of Other Equity Interest (Detail) $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)	Dec. 31, 2019 TWD ($)
Disclosure of Other Equity Interest [Line Items]
Beginning balance	$ 133,386
Ending balance	221,840	$ 7,997	$ 133,386
Financial statements translation differences of foreign operations [member]
Disclosure of Other Equity Interest [Line Items]
Beginning balance	(61,330)		(89,682)	$ 14,516
Currency translation differences - The company	(24,695)		28,352	(104,198)
Ending balance	(86,025)		(61,330)	(89,682)
Unrealized gain (loss) on valuation of financial assets at fair value through other comprehensive income [member]
Disclosure of Other Equity Interest [Line Items]
Beginning balance	194,716		66,386	106,898
Evaluation adjustment - The Company	122,514		140,199	(52,549)
Evaluation adjustment - Associates	21,094		22,925	5,093
Evaluation adjustment related tax - The Company	(30,459)		(34,794)	7,016
Disposal of investment accounted for using equity method				(72)
Ending balance	307,865		194,716	66,386
Unearned employee awards [member]
Disclosure of Other Equity Interest [Line Items]
Beginning balance				(1,701)
Employee restricted shares - The company				1,701
Other equity interest [member]
Disclosure of Other Equity Interest [Line Items]
Beginning balance	133,386		(23,296)	119,713
Currency translation differences - The company	(24,695)		28,352	(104,198)
Employee restricted shares - The company				1,701
Evaluation adjustment - The Company	122,514		140,199	(52,549)
Evaluation adjustment - Associates	21,094		22,925	5,093
Evaluation adjustment related tax - The Company	(30,459)		(34,794)	7,016
Disposal of investment accounted for using equity method				(72)
Ending balance	$ 221,840		$ 133,386	$ (23,296)

Revenue - Summary of Revenue From Contracts with Customers (Detail) - TWD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Receivables from contracts with customers [abstract]
Revenue from contracts with customers	$ 27,400,035	$ 23,011,381	$ 20,337,881

Revenue - Summary of Contract Assets and Liabilities (Detail) - TWD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Jan. 01, 2020
Disclosure of contract assets and liabilities in relation to revenue [Abstract]
Contract assets	$ 400,255	$ 389,016	$ 377,869
Contract liabilities (Advance payments)			$ 1,231

Revenue - Additional Information (Detail) - TWD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure of major customers [abstract]
Revenue recognized in current reporting period related to carried-forward contract liabilities for performance obligation not satisfied in prior year	$ 0	$ 565

Other Income (Expenses), Net - Summary of Other Income (Expenses), Net (Detail) $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)	Dec. 31, 2019 TWD ($)
Analysis of income and expense [abstract]
Gain on disposal of scrapped materials	$ 52,254		$ 51,077	$ 43,652
Royalty income	907		2,962	12,336
Gain on disposal of items purchased on behalf of others	21,945		30,140	15,080
Gain on disposal of property, plant and equipment, net	33,935		48,070	20,271
Insurance compensation income				10,435
Impairment loss on property, plant and equipment	(4,843)			(9,938)
Gains from lease modifications	891
Others	20,498		3,329	1,092
Other income (expenses), net	$ 125,587	$ 4,527	$ 135,578	$ 92,928

Interest income - Disclosure of interest income (Details) $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)	Dec. 31, 2019 TWD ($)
Disclosure of Interest Income [Abstract]
Bank deposits	$ 8,772		$ 25,547	$ 59,901
Financial assets at amortized cost	1,187		2,206	4,467
Other interest income	21		25
Interest income	$ 9,980	$ 360	$ 27,778	$ 64,368

Other Income - Summary of Other income (Detail) - TWD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Analysis of other income [Abstract]
Rental income	$ 17,326	$ 10,260	$ 9,249
Dividend income	4,690	3,229	585
Grant income	12,480	7,668	925
Other non-operating income (expenses), net	$ 34,496	$ 21,157	$ 10,759

Other gains and losses - Summary of Other gains and losses (Details) $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)	Dec. 31, 2019 TWD ($)
Disclosure of Other gains and losses [Abstract]
Foreign exchange losses, net	$ (89,152)		$ (355,255)	$ (154,993)
Reimbursement of ADSs service charge	2,284		2,101	4,292
Gain on valuation of financial assets at fair value through profit or loss	15,262		24,015	1,317
Compensation income	1,524
Others	4,253		5,872	970
Total	$ (65,829)	$ (2,373)	$ (323,267)	$ (148,414)

Finance Costs - Summary of Finance Costs (Detail) $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)	Dec. 31, 2019 TWD ($)
Analysis of Finance Costs [abstract]
Bank loans	$ 116,946		$ 158,720	$ 171,840
Lease liabilities	15,245		13,442	14,349
Less: Amounts capitalized in qualifying assets	(11,193)		(9,762)	(15,114)
Interest expense	120,998		162,400	171,075
Finance expense	10,186		9,082	9,187
Finance costs	$ 131,184	$ 4,729	$ 171,482	$ 180,262

Expenses by nature - Summary of Expenses by nature (Detail) - TWD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Analysis of income and expense [abstract]
Raw materials and supplies used	$ 5,518,145	$ 4,708,493	$ 3,575,283
Employee benefit expenses	6,757,888	6,010,227	6,075,773
Depreciation expenses	4,634,112	4,175,519	3,731,914
Others	5,053,088	4,686,218	4,590,720
Total operating costs and expenses	$ 21,963,233	$ 19,580,457	$ 17,973,690

Employee benefit expenses - Summary of Employee benefit expenses (Detail) - TWD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Classes of employee benefits expense [abstract]
Salaries	$ 5,632,219	$ 4,937,591	$ 5,114,790
Directors' remuneration	40,164	28,229	26,266
Labor and health insurance	424,901	396,796	422,106
Pension	200,014	189,489	194,173
Share-based payments			822
Other personnel expenses	460,590	458,122	317,616
Total Employee benefit expenses	$ 6,757,888	$ 6,010,227	$ 6,075,773

Employee benefit expenses - Additional Information (Detail) - TWD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of defined benefit plans [Line Items]
Accrued Employee Compensation	$ 673,387	$ 332,080	$ 338,356
Accrued Directors remuneration	$ 25,690	$ 16,604	$ 16,918
Defined benefit pension plan [Member]
Disclosure of defined benefit plans [Line Items]
Employees' compensation distribution rate	10.00%
Director remuneration rate no more than	0.50%

Income Tax Expense - Additional Information (Detail) - TWD ($) $ in Thousands		3 Months Ended
	Oct. 31, 2016	Jun. 30, 2020	Dec. 31, 2021	Dec. 31, 2020
Disclosure of income tax expense [Line Items]
Taxable temporary differences not recognized as deferred tax liaibility			$ 609,709	$ 45,005
Reduction of unappropriated retained earnings through capital transfer	$ 5,052,343
Income taxes paid (refund)		$ 138,941

Income Tax Expense - Major Components of Income Tax Expense (Detail) $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)	Dec. 31, 2019 TWD ($)
Current income tax:
Current income tax on profits for the period	$ 1,109,752		$ 636,876	$ 408,788
Income tax on unappropriated retained earnings	227,467		105,665	74,540
Prior year income tax overestimation	(184,284)		(133,923)	(5,016)
Total current income tax	1,152,935		608,618	478,312
Deferred income tax:
Relating to origination and reversal of temporary differences	(54,617)		(14,237)	35,367
Income tax expense	$ 1,098,318	$ 39,593	$ 594,381	$ 513,679

The aggregate amount included in the determination of profit (loss) for the period in respect of current tax and deferred tax. [Refer: Current tax expense (income); Deferred tax expense (income)]

Income Tax Expense - Deferred Tax Charged to Other Comprehensive Income (Detail) $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)	Dec. 31, 2019 TWD ($)
Income tax relating to components of other comprehensive income [abstract]
Unrealized gain (loss) on valuation of financial assets at fair value through other comprehensive income	$ 30,459		$ 34,794	$ (7,016)
Remeasurement of defined benefit obligations	(2,999)		(10,398)	4,183
Total	$ 27,460	$ 990	$ 24,396	$ (2,833)

Income Tax Expense - Reconciliation of Income Tax Expense and Accounting Profit Before Income Tax (Detail) $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)	Dec. 31, 2019 TWD ($)
Reconciliation of income tax expense and accounting profit before income tax [abstract]
Tax calculated based on profit before tax and statutory tax rate	$ 1,207,605		$ 595,258	$ 606,917
Effects from adjustments based on regulation	(152,618)		26,974	(162,924)
Temporary difference not recognized as deferred tax assets			(4)	(608)
Prior year income tax overestimation	(184,284)		(133,923)	(5,016)
Income tax on unappropriated retained earnings	227,467		105,665	74,540
Effect of different tax rates in countries in which the Group operates	148		411	770
Income tax expense	$ 1,098,318	$ 39,593	$ 594,381	$ 513,679

The aggregate amount included in the determination of profit (loss) for the period in respect of current tax and deferred tax. [Refer: Current tax expense (income); Deferred tax expense (income)]

Income Tax Expense - Details of Deferred Tax Assets (Liabilities) (Detail) $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 TWD ($)	Dec. 31, 2020 TWD ($)	Dec. 31, 2019 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2018 TWD ($)
Disclosure of the detail of deferred tax assets and liabilities [line items]
Deferred tax assets	$ 180,598	$ 185,691	$ 194,552	$ 6,510	$ 226,716
Deferred tax liabilities	(278,177)	(310,427)	(309,129)	$ (10,028)	$ (308,759)
Deferred tax assets unrealized loss on inventories [member]
Disclosure of the detail of deferred tax assets and liabilities [line items]
Beginning balance	15,963	12,700	7,232
Recognized in profit or loss	8,354	3,263	5,468
Ending balance	24,317	15,963	12,700
Property, plant and equipment, deferred tax assets [member]
Disclosure of the detail of deferred tax assets and liabilities [line items]
Beginning balance	36,401	38,668	64,183
Recognized in profit or loss	235	(2,267)	(25,515)
Ending balance	36,636	36,401	38,668
Provisions [member]
Disclosure of the detail of deferred tax assets and liabilities [line items]
Beginning balance	2,678	5,600	12,396
Recognized in profit or loss	171	(2,922)	(6,796)
Ending balance	2,849	2,678	5,600
Deferred tax assets deferred revenue [member]
Disclosure of the detail of deferred tax assets and liabilities [line items]
Beginning balance	21,144	27,650	34,156
Recognized in profit or loss	(6,506)	(6,506)	(6,506)
Ending balance	14,638	21,144	27,650
Net defined benefit liability [member]
Disclosure of the detail of deferred tax assets and liabilities [line items]
Beginning balance	98,921	92,612	100,743
Recognized in profit or loss	(4,672)	(4,089)	(3,948)
Recognized in other comprehensive income	2,999	10,398	(4,183)
Ending balance	97,248	98,921	92,612
Unrealized exchange losses deferred tax assets [member]
Disclosure of the detail of deferred tax assets and liabilities [line items]
Beginning balance	9,915	17,296	3,575
Recognized in profit or loss	(7,754)	(7,381)	13,721
Ending balance	2,161	9,915	17,296
Investment tax credit [member]
Disclosure of the detail of deferred tax assets and liabilities [line items]
Beginning balance			4,420
Recognized in profit or loss			(4,420)
Others [member]
Disclosure of the detail of deferred tax assets and liabilities [line items]
Beginning balance	669	26	11
Recognized in profit or loss	2,080	643	15
Ending balance	2,749	669	26
Deferred tax asset [member]
Disclosure of the detail of deferred tax assets and liabilities [line items]
Beginning balance	185,691	194,552	226,716
Recognized in profit or loss	(8,092)	(19,259)	(27,981)
Recognized in other comprehensive income	2,999	10,398	(4,183)
Ending balance	180,598	185,691	194,552
Property, plant and equipment, deferred tax liabilities [member]
Disclosure of the detail of deferred tax assets and liabilities [line items]
Beginning balance	(255,484)	(288,980)	(281,594)
Recognized in profit or loss	62,797	33,496	(7,386)
Ending balance	(192,687)	(255,484)	(288,980)
Financial assets at fair value through other comprehensive income [member]
Disclosure of the detail of deferred tax assets and liabilities [line items]
Beginning balance	(54,943)	(20,149)	(27,165)
Recognized in other comprehensive income	(30,459)	(34,794)	7,016
Ending balance	(85,402)	(54,943)	(20,149)
Deferred tax liabilities [member]
Disclosure of the detail of deferred tax assets and liabilities [line items]
Beginning balance	(310,427)	(309,129)	(308,759)
Recognized in profit or loss	62,709	33,496	(7,386)
Recognized in other comprehensive income	(30,459)	(34,794)	7,016
Ending balance	(278,177)	$ (310,427)	$ (309,129)
Others [member]
Disclosure of the detail of deferred tax assets and liabilities [line items]
Recognized in profit or loss	(88)
Ending balance	$ (88)

Income tax expense - Summary of Deductible Temporary Differences for which No Deferred Tax Asset Is Recognized (Detail) - TWD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Disclosure of Detailed Information about Deductible Temporary Difference that are Not Recognized as Deferred Tax Assets Explanatory [Abstract]
Deductible temporary differences	$ 371,133	$ 946,236

Earnings Per Share - Income and Share Data Used in Basic and Diluted EPS Computations (Detail) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 TWD ($) $ / shares shares	Dec. 31, 2021 $ / shares	Dec. 31, 2020 TWD ($) $ / shares shares	Dec. 31, 2019 TWD ($) $ / shares shares
Basic earnings per share, amount after tax
Equity holders of the Company - Amount after tax \| $	$ 4,937,267		$ 2,378,978	$ 2,508,574
Diluted earnings per share, amount after tax
Equity holders of the Company - Amount after tax \| $	$ 4,937,267		$ 2,378,978	$ 2,508,574
Weighted average number of ordinary shares outstanding	727,240		727,240	727,111
Diluted earnings per share, weighted-average number of ordinary shares outstanding
Employees' compensation	15,618		9,668	9,879
Restricted shares				126
Weighted average number of ordinary shares outstanding	742,858		736,908	737,116
Ordinary shares [member]
Basic earnings per share
Equity holders of the Company - Earnings per share \| (per share)	$ 6.79	$ 0.24	$ 3.27	$ 3.45
Diluted earnings per share
Equity holders of the Company - Earnings per share \| (per share)	$ 6.65	$ 0.24	$ 3.23	$ 3.40

Supplementary Cash Flow Information - Partial Cash Paid for Investing Activities (Detail) $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)	Dec. 31, 2019 TWD ($)
Statement of cash flows [abstract]
Purchase of property, plant and equipment	$ 6,552,702		$ 4,133,615	$ 4,896,656
Add: Beginning balance of payable to contractors and equipment suppliers	1,145,359		972,770	1,516,735
Less: Ending balance of payable to contractors and equipment suppliers	(1,816,555)		(1,145,359)	(972,770)
Cash paid during the year	$ 5,881,506	$ 212,023	$ 3,961,026	$ 5,440,621

Changes in liabilities from financing activities - Reconciliation of Liabilities Arising from Financing Activities (Detail) - TWD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning balance	$ 8,625,730	$ 9,735,691	$ 9,790,610
Effects on initial application of IFRS 16			884,275
Adjusted balance at January 1, 2019			10,674,885
Changes in cash flow from financing activities	2,094,370	(1,411,210)	(804,608)
Adjustment to right-of-use assets	255,179	249,030	(148,512)
Reclassification to payable on equipment from lease liabilities			(9,000)
Reclassification		20,000
Amortization Of Interest Expense	35,067	24,638	14,349
Amortization of loan fees	7,646	7,581	8,577
Ending balance	11,017,992	8,625,730	9,735,691
Long-term bank loans (include the current portion) [member]
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning balance	7,733,565	9,041,645	9,789,518
Adjusted balance at January 1, 2019			9,789,518
Changes in cash flow from financing activities	1,652,332	(1,326,857)	(756,450)
Amortization Of Interest Expense	19,822	11,196
Amortization of loan fees	7,646	7,581	8,577
Ending balance	9,413,365	7,733,565	9,041,645
Short-term bank loans [member]
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Changes in cash flow from financing activities	731,751
Ending balance	731,751
Guarantee deposits [member]
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning balance	21,670	1,095	1,092
Adjusted balance at January 1, 2019			1,092
Changes in cash flow from financing activities	(45)	575	3
Reclassification		20,000
Ending balance	21,625	21,670	1,095
Lease liabilities [member]
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning balance	870,495	692,951
Effects on initial application of IFRS 16			884,275
Adjusted balance at January 1, 2019			884,275
Changes in cash flow from financing activities	(289,668)	(84,928)	(48,161)
Adjustment to right-of-use assets	255,179	249,030	(148,512)
Reclassification to payable on equipment from lease liabilities			(9,000)
Amortization Of Interest Expense	15,245	13,442	14,349
Ending balance	$ 851,251	$ 870,495	$ 692,951

Related Party Transactions - Summary of Names of Related Parties and Relationship (Detail)	12 Months Ended
	Dec. 31, 2021
Unimos Shanghai [member]
Disclosure of transactions between related parties [Line Items]
Relationship	Associate
JMC ELECTRONICS CO., LTD. [member]
Disclosure of transactions between related parties [Line Items]
Relationship	Associate

Related Party Transactions - Key Management Personnel Compensation (Detail) - TWD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of transactions between related parties [abstract]
Salaries and other short-term employee benefits	$ 243,405	$ 186,854	$ 178,713
Post-employment compensation	2,156	4,258	2,049
Total key management personnel compensation	$ 245,561	$ 191,112	$ 180,762

Pledged assets - Certain Assets Provided as Collateral Mainly for Long-term Bank Loans and Leases (Detail) - TWD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Statement [LineItems]
Purpose	Lease and bank loan
Non-current financial assets at amortized cost	$ 37,539	$ 48,319
Assets pledged as collateral for liabilities	$ 13,079,394	11,505,888
Land [member]
Statement [LineItems]
Purpose	Bank loan
Property, plant and equipment, net	$ 452,738	452,738
Buildings [member]
Statement [LineItems]
Purpose	Bank loan
Property, plant and equipment, net	$ 4,343,556	4,092,287
Machinery and equipment [member]
Statement [LineItems]
Purpose	Bank loan
Property, plant and equipment, net	$ 8,245,561	$ 6,912,544

Significant contingent liabilities and unrecognized contract commitments - Additional Information (Detail) - TWD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Capital commitments [abstract]
Amounts guaranteed by the financial institutions	$ 137,700	$ 99,000

Significant contingent liabilities and unrecognized contract commitments - Capital Expenditures that are Contracted for, but not Provided for (Detail) - TWD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Disclosure of detailed information about property, plant and equipment [abstract]
Property plant and equipment, Contracted capital expenditures	$ 2,629,129	$ 2,331,041

Capital Management - Percentages of Liabilities to Assets Ratio Used for Monitoring Capital (Detail) $ in Thousands, $ in Thousands	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)
Disclosure of objectives, policies and processes for managing capital [abstract]
Total liabilities	$ 18,380,369	$ 662,595	$ 14,364,975
Total assets	$ 42,522,584	$ 1,532,898	$ 35,080,814
Liabilities to assets ratio	43.22%	43.22%	40.95%

Financial Risk Management and Fair Values of Financial Instruments - Summary of Financial Instruments by Category (Detail) $ in Thousands, $ in Thousands	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)
Financial assets at fair value through profit or loss
Financial assets mandatorily measured at fair value through profit or loss	$ 359,960		$ 63,488
Financial assets at fair value through other comprehensive income
Designation of equity instruments	384,521		262,007
Financial assets at amortized cost
Cash and cash equivalents	5,906,176	$ 212,912	4,113,651
Financial assets at amortized cost	66,778		254,801
Notes receivable	1,035	37	599
Accounts receivable	6,344,246	228,704	5,364,156
Other receivables	86,879	3,132	51,436
Refundable deposits	21,278	767	21,186
Financial assets	13,170,873		10,131,324
Financial liabilities at amortized cost
Short-term bank loans	731,751	26,379
Notes payable	23	1	2,899
Accounts payable	1,012,391	36,496	966,821
Other payables	4,378,439	157,838	3,249,403
Long-term bank loans (including current portion)	9,413,365		7,733,565
Lease liabilities (including current portion)	851,251		870,495
Guarantee deposits	21,625	$ 779	21,670
Financial liabilities	$ 16,408,845		$ 12,844,853

Financial Risk Management and Fair Values of Financial Instruments - Information on Assets and Liabilities Denominated in Foreign Currencies whose Values would be Materially Affected by Exchange Rate Fluctuations (Detail) ¥ in Thousands, ¥ in Thousands, $ in Thousands, $ in Thousands	Dec. 31, 2021 TWD ($) $ / USD $ / JPY $ / CNY	Dec. 31, 2021 USD ($) $ / USD $ / JPY $ / CNY	Dec. 31, 2021 JPY (¥) $ / USD $ / JPY $ / CNY	Dec. 31, 2021 CNY (¥) $ / USD $ / JPY $ / CNY	Dec. 31, 2020 TWD ($) $ / USD $ / JPY $ / CNY	Dec. 31, 2020 USD ($) $ / USD $ / JPY $ / CNY	Dec. 31, 2020 JPY (¥) $ / USD $ / JPY $ / CNY	Dec. 31, 2020 CNY (¥) $ / USD $ / JPY $ / CNY
Disclosure of detailed information about financial instruments [Line Items]
Assets denominated in foreign currencies \| $	$ 13,170,873				$ 10,131,324
Exchange rate	27.74	27.74	27.74	27.74
Currency Risk [member] \| US$ [member]
Disclosure of detailed information about financial instruments [Line Items]
Assets denominated in foreign currencies	$ 5,207,798	$ 188,143			5,007,923	$ 175,840
Liabilities denominated in foreign currencies	$ 1,468,203	$ 53,042			$ 752,157	$ 26,410
Currency Risk [member] \| US$ [member] \| Financial Liability [member]
Disclosure of detailed information about financial instruments [Line Items]
Exchange rate \| $ / USD	27.6800	27.6800	27.6800	27.6800	28.4800	28.4800	28.4800	28.4800
Currency Risk [member] \| US$ [member] \| Financial Asset [member]
Disclosure of detailed information about financial instruments [Line Items]
Exchange rate \| $ / USD	27.6800	27.6800	27.6800	27.6800	28.4800	28.4800	28.4800	28.4800
Currency Risk [member] \| JPY [member]
Disclosure of detailed information about financial instruments [Line Items]
Assets denominated in foreign currencies	$ 34,036		¥ 141,523		$ 38,029		¥ 137,635
Liabilities denominated in foreign currencies	$ 262,005		¥ 1,089,668		$ 425,016		¥ 1,538,241
Currency Risk [member] \| JPY [member] \| Financial Liability [member]
Disclosure of detailed information about financial instruments [Line Items]
Exchange rate	0.2405	0.2405	0.2405	0.2405	0.2763	0.2763	0.2763	0.2763
Currency Risk [member] \| JPY [member] \| Financial Asset [member]
Disclosure of detailed information about financial instruments [Line Items]
Exchange rate	0.2405	0.2405	0.2405	0.2405	0.2763	0.2763	0.2763	0.2763
Currency Risk [member] \| RMB [member]
Disclosure of detailed information about financial instruments [Line Items]
Assets denominated in foreign currencies	$ 21,477			¥ 4,944	$ 29,930			¥ 6,838
Currency Risk [member] \| RMB [member] \| Financial Asset [member]
Disclosure of detailed information about financial instruments [Line Items]
Exchange rate \| $ / CNY	4.3440	4.3440	4.3440	4.3440	4.3770	4.3770	4.3770	4.3770
Other Risks [Member] \| JPY [member]
Disclosure of detailed information about financial instruments [Line Items]
Assets denominated in foreign currencies	$ 384,521		¥ 1,598,839		$ 262,007		¥ 948,270
Other Risks [Member] \| JPY [member] \| Financial Asset [member]
Disclosure of detailed information about financial instruments [Line Items]
Exchange rate	0.2405	0.2405	0.2405	0.2405	0.2763	0.2763	0.2763	0.2763
Other Risks [Member] \| RMB [member]
Disclosure of detailed information about financial instruments [Line Items]
Assets denominated in foreign currencies	$ 3,596,012			¥ 827,811	$ 3,020,908			¥ 690,178
Other Risks [Member] \| RMB [member] \| Financial Asset [member]
Disclosure of detailed information about financial instruments [Line Items]
Exchange rate \| $ / CNY	4.3440	4.3440	4.3440	4.3440	4.3770	4.3770	4.3770	4.3770

Financial Risk Management and Fair Values of Financial Instruments - Additional Information (Detail) - TWD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of detailed information about financial instruments [Line Items]
Realized and unrealized gain and loss arising from significant foreign exchange variation	$ (89,152)	$ (355,255)	$ (154,993)
General increase or decrease of 100 basis points (1%) in interest rates [member]
Disclosure of detailed information about financial instruments [Line Items]
Estimated decrease or increase in the Group's profit and equity based on an increase or decrease in the interest rates	102,489	78,150	90,660
Equity price risk [member]
Disclosure of detailed information about financial instruments [Line Items]
Estimated decrease or increase in the Group's profit and equity based on an increase or decrease in the interest rates	$ 3,600	$ 531	$ 0
Adjustments to interest rate	1.00%	1.00%	1.00%

Financial Risk Management and Fair Values of Financial Instruments - Details of Exposure to Currency Risk Arising from Recognized Monetary Assets or Liabilities Denominated in a Currency Other Than Functional Currency (Detail) - Currency Risk [member] - TWD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Financial assets, class [member] \| US$ [member]
Disclosure of nature and extent of risks arising from financial instruments [Line Items]
Change in exchange rate	5.00%	5.00%	5.00%
Financial assets, class [member] \| JPY [member]
Disclosure of nature and extent of risks arising from financial instruments [Line Items]
Change in exchange rate	5.00%	5.00%	5.00%
Financial assets, class [member] \| RMB [member]
Disclosure of nature and extent of risks arising from financial instruments [Line Items]
Change in exchange rate	5.00%	5.00%	5.00%
Financial liabilities, class [member] \| US$ [member]
Disclosure of nature and extent of risks arising from financial instruments [Line Items]
Change in exchange rate	5.00%	5.00%	5.00%
Financial liabilities, class [member] \| JPY [member]
Disclosure of nature and extent of risks arising from financial instruments [Line Items]
Change in exchange rate	5.00%	5.00%	5.00%
Profit and Loss [member] \| Financial assets, class [member] \| US$ [member]
Disclosure of nature and extent of risks arising from financial instruments [Line Items]
Effect of change in exchange rate	$ 260,390	$ 250,396	$ 282,365
Profit and Loss [member] \| Financial assets, class [member] \| JPY [member]
Disclosure of nature and extent of risks arising from financial instruments [Line Items]
Effect of change in exchange rate	1,702	1,901	3,682
Profit and Loss [member] \| Financial assets, class [member] \| RMB [member]
Disclosure of nature and extent of risks arising from financial instruments [Line Items]
Effect of change in exchange rate	1,074	1,497	1,334
Profit and Loss [member] \| Financial liabilities, class [member] \| US$ [member]
Disclosure of nature and extent of risks arising from financial instruments [Line Items]
Effect of change in exchange rate	73,410	37,608	11,793
Profit and Loss [member] \| Financial liabilities, class [member] \| JPY [member]
Disclosure of nature and extent of risks arising from financial instruments [Line Items]
Effect of change in exchange rate	$ 13,103	$ 21,251	$ 14,261

Financial Risk Management and Fair Values of Financial Instruments - Summary of Loss Rate Methodology (Detail) - TWD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Contract assets [member]
Disclosure of detailed information about financial instruments [Line Items]
Expected loss rate	0.03%	0.03%
Total carrying amount	$ 400,375	$ 389,133
Loss allowance	$ (120)	$ (117)
Accounts receivable including related parties [member]
Disclosure of detailed information about financial instruments [Line Items]
Expected loss rate	0.03%	0.03%
Total carrying amount	$ 6,346,156	$ 5,365,776
Loss allowance	$ (1,910)	$ (1,620)
Other receivable including related parties [member]
Disclosure of detailed information about financial instruments [Line Items]
Expected loss rate	0.03%	0.03%
Total carrying amount	$ 86,895	$ 51,446
Loss allowance	$ (16)	$ (10)

Financial Risk Management and Fair Values of Financial Instruments - Summary of Movements in Relation to Loss Allowance for Contract Assets, Accounts Receivable and Other Receivables (Detail) - TWD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of detailed information about financial instruments [Line Items]
Financial assets beginning balance	$ 10,131,324
Financial assets ending balance	13,170,873	$ 10,131,324
Contract assets [member]
Disclosure of detailed information about financial instruments [Line Items]
Financial assets beginning balance	(117)	(114)	$ (135)
Provision for impairment loss	(3)	(3)
Reversal of impairment loss			21
Financial assets ending balance	(120)	(117)	(114)
Accounts receivable including related parties [member]
Disclosure of detailed information about financial instruments [Line Items]
Financial assets beginning balance	(1,620)	(1,351)	(2,141)
Provision for impairment loss	(290)	(269)
Reversal of impairment loss			790
Financial assets ending balance	(1,910)	(1,620)	(1,351)
Other receivable including related parties [member]
Disclosure of detailed information about financial instruments [Line Items]
Financial assets beginning balance	(10)	(18)	(13)
Provision for impairment loss	(6)		(5)
Reversal of impairment loss		8
Financial assets ending balance	$ (16)	$ (10)	$ (18)

The amount of assets that are: (a) cash; (b) an equity instrument of another entity; (c) a contractual right: (i) to receive cash or another financial asset from another entity; or (ii) to exchange financial assets or financial liabilities with another entity under conditions that are potentially favourable to the entity; or (d) a contract that will, or may be, settled in the entity’s own equity instruments and is: (i) a non-derivative for which the entity is, or may be, obliged to receive a variable number of the entity’s own equity instruments; or (ii) a derivative that will, or may be, settled other than by the exchange of a fixed amount of cash or another financial asset for a fixed number of the entity’s own equity instruments. For this purpose the entity’s own equity instruments do not include puttable financial instruments classified as equity instruments in accordance with paragraphs 16A-16B of IAS 32, instruments that impose on the entity an obligation to deliver to another party a pro rata share of the net assets of the entity only on liquidation and are classified as equity instruments in accordance with paragraphs 16C-16D of IAS 32, or instruments that are contracts for the future receipt or delivery of the entity’s own equity instruments. [Refer: Financial instruments, class [member]; Financial liabilities]

Financial Risk Management and Fair Values of Financial Instruments - Maturity Profile of Non-derivative Financial Liabilities Based on Contracted Undiscounted Payments (Detail) - TWD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Disclosure of maturity analysis for non-derivative financial liabilities [Line Items]
Short-term bank loans	$ 733,523
Long-term bank loans	9,766,486	$ 8,091,523
Lease liabilities	1,047,811	1,079,181
Guarantee deposits	21,625	21,670
Total	11,569,445	9,192,374
Within 1 year [member]
Disclosure of maturity analysis for non-derivative financial liabilities [Line Items]
Short-term bank loans	733,523
Long-term bank loans	114,953	846,401
Lease liabilities	182,186	145,594
Total	1,030,662	991,995
1 to 3 years [member]
Disclosure of maturity analysis for non-derivative financial liabilities [Line Items]
Long-term bank loans	2,817,662	3,558,597
Lease liabilities	119,748	160,146
Total	2,937,410	3,718,743
3 to 5 years [member]
Disclosure of maturity analysis for non-derivative financial liabilities [Line Items]
Long-term bank loans	4,568,521	2,198,717
Lease liabilities	54,113	54,689
Total	4,622,634	2,253,406
Over 5 years [member]
Disclosure of maturity analysis for non-derivative financial liabilities [Line Items]
Long-term bank loans	2,265,350	1,487,808
Lease liabilities	691,764	718,752
Guarantee deposits	21,625	21,670
Total	$ 2,978,739	$ 2,228,230

Financial Risk Management and Fair Values of Financial Instruments - Summary of Natures of Assets and Liabilities (Detail) - TWD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure of detailed information about financial instruments [Line Items]
Financial assets at fair value through profit or loss	$ 359,960	$ 63,488
Financial assets at fair value	744,481	325,495
Foreign partnership interests [member] \| Recurring fair value measurement [member]
Disclosure of detailed information about financial instruments [Line Items]
Financial assets at fair value through profit or loss		10,368
Foreign unlisted stocks [member] \| Recurring fair value measurement [member]
Disclosure of detailed information about financial instruments [Line Items]
Financial assets at fair value through other comprehensive income	384,521	262,007
Listed stocks [member] \| Recurring fair value measurement [member]
Disclosure of detailed information about financial instruments [Line Items]
Financial assets at fair value through profit or loss	359,960	53,120
Level 1 [member]
Disclosure of detailed information about financial instruments [Line Items]
Financial assets at fair value	359,960	53,120
Level 1 [member] \| Listed stocks [member] \| Recurring fair value measurement [member]
Disclosure of detailed information about financial instruments [Line Items]
Financial assets at fair value through profit or loss	359,960	53,120
Level 3 [member]
Disclosure of detailed information about financial instruments [Line Items]
Financial assets at fair value	384,521	272,375
Level 3 [member] \| Foreign partnership interests [member] \| Recurring fair value measurement [member]
Disclosure of detailed information about financial instruments [Line Items]
Financial assets at fair value through profit or loss		10,368
Level 3 [member] \| Foreign unlisted stocks [member] \| Recurring fair value measurement [member]
Disclosure of detailed information about financial instruments [Line Items]
Financial assets at fair value through other comprehensive income	$ 384,521	$ 262,007

Financial Risk Management and Fair Values of Financial Instruments - Summary of Movements of Level 3 (Detail) - TWD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure of detailed information about financial instruments [Line Items]
Movement of financial instruments beginning balance	$ 272,375	$ 132,846
Gains or losses recognized in profit or loss Recorded as non-operating income (expenses)	(941)	(670)
Gains or losses recognized in other comprehensive gains (losses) Recorded as unrealized gains on valuation of financial assets at fair value through other comprehensive income	122,514	140,199
Sold in the period	(9,427)
Movement of financial instruments ending balance	384,521	272,375
Debt instruments [member]
Disclosure of detailed information about financial instruments [Line Items]
Movement of financial instruments beginning balance	10,368	11,038
Gains or losses recognized in profit or loss Recorded as non-operating income (expenses)	(941)	(670)
Sold in the period	(9,427)
Movement of financial instruments ending balance		10,368
Equity instruments [member]
Disclosure of detailed information about financial instruments [Line Items]
Movement of financial instruments beginning balance	262,007	121,808
Gains or losses recognized in other comprehensive gains (losses) Recorded as unrealized gains on valuation of financial assets at fair value through other comprehensive income	122,514	140,199
Movement of financial instruments ending balance	$ 384,521	$ 262,007

Financial Risk Management and Fair Values of Financial Instruments - Summary of Qualitative Information and Sensitivity Analysis of Changes in Significant Unobservable Inputs Under Valuation Model Used in Level Fair Value Measurement (Detail) - TWD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Non derivative equity instruments [member] \| Foreign unlisted stocks [member]
Disclosure of significant unobservable inputs used in fair value measurement of equity [line items]
Fair value	$ 384,521,000	$ 262,007,000
Valuation technique	Comparable companies	Comparable companies
Non derivative equity instruments [member] \| Foreign unlisted stocks [member] \| Price book value multiple [member]
Disclosure of significant unobservable inputs used in fair value measurement of equity [line items]
Range (weighted average method)	$ 3.46	$ 1.97
Relationship of inputs to fair value	The higher the multiple, the higher the fair value	The higher the multiple, the higher the fair value
Non derivative equity instruments [member] \| Foreign unlisted stocks [member] \| Enter prise value EBITDA multiple [member]
Disclosure of significant unobservable inputs used in fair value measurement of equity [line items]
Range (weighted average method)	$ 9.43	$ 12.00
Relationship of inputs to fair value	The higher the multiple, the higher the fair value	The higher the multiple, the higher the fair value
Non derivative equity instruments [member] \| Foreign unlisted stocks [member] \| Discount for lack of marketability [member]
Disclosure of significant unobservable inputs used in fair value measurement of equity [line items]
Range (weighted average method)	15.80%	15.80%
Relationship of inputs to fair value	The higher the discount for lack of marketability, the lower the fair value	The higher the discount for lack of marketability, the lower the fair value
Non derivative debt instruments [member] \| Foreign partnership interests [member]
Disclosure of significant unobservable inputs used in fair value measurement of equity [line items]
Fair value		$ 10,368,000
Valuation technique		Discounted cash flow
Non derivative debt instruments [member] \| Foreign partnership interests [member] \| Discount rate [member]
Disclosure of significant unobservable inputs used in fair value measurement of equity [line items]
Range (weighted average method)		0.30%
Relationship of inputs to fair value		The lower the discount rate, the higher the fair value

Financial Risk Management And Fair Values Of Financial Instruments - Summary of Effect of Profit or Loss or of Other Comprehensive Income from Financial Assets Categorized (Detail) - Financial instruments at fair value through other comprehensive income [member] - TWD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure of significant unobservable inputs used in fair value measurement of equity [line items]
Favorable Changes	$ 8,074	$ 5,325
Unfavorable Changes In Fair Value	8,074	5,267
Enter prise value EBITDA multiple [member]
Disclosure of significant unobservable inputs used in fair value measurement of equity [line items]
Favorable Changes	3,443	2,153
Unfavorable Changes In Fair Value	3,443	2,153
Discount for lack of marketability [member]
Disclosure of significant unobservable inputs used in fair value measurement of equity [line items]
Favorable Changes	4,585	3,142
Unfavorable Changes In Fair Value	4,585	3,084
Foreign unlisted stocks [member] \| Price to book ratio multiple [member]
Disclosure of significant unobservable inputs used in fair value measurement of equity [line items]
Favorable Changes	46	30
Unfavorable Changes In Fair Value	$ 46	$ 30

Segment Information - Financial Segment Information for Operating Segments (Detail) $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)	Dec. 31, 2019 TWD ($)
Revenue
Revenue	$ 27,400,035	$ 987,745	$ 23,011,381	$ 20,337,881
Operating profit (loss)	5,562,389	200,519	3,566,502	2,457,119
Share of profit (loss) of associates	625,733	$ 22,557	(147,329)	(154,926)
Interest expense	(120,998)		(162,400)	(171,075)
Purchase of property, plant and equipment	6,552,702		4,133,615	4,896,656
Continuing operations [member]
Revenue
Revenue	27,400,035		23,011,381	20,337,881
Operating profit (loss)	5,562,389		3,566,502	2,457,119
Depreciation expenses	(4,634,112)		(4,175,519)	(3,731,914)
Share of profit (loss) of associates	625,733		(147,329)	(154,926)
Interest income	9,980		27,778	64,368
Interest expense	(120,998)		(162,400)	(171,075)
Purchase of property, plant and equipment	6,552,702		4,133,615	4,896,656
Continuing operations [member] \| External [member]
Revenue
Revenue	27,400,035		23,011,381	20,337,881
Continuing operations [member] \| Operating segments [member] \| Testing [member]
Revenue
Revenue	5,899,600		5,002,730	4,257,800
Operating profit (loss)	1,814,021		1,333,682	709,142
Depreciation expenses	(921,999)		(853,829)	(802,740)
Purchase of property, plant and equipment	1,841,359		887,204	764,105
Continuing operations [member] \| Operating segments [member] \| Testing [member] \| External [member]
Revenue
Revenue	5,899,600		5,002,730	4,257,800
Continuing operations [member] \| Operating segments [member] \| Assembly [member]
Revenue
Revenue	7,963,714		6,001,964	5,148,877
Operating profit (loss)	857,304		67,730	(227,096)
Depreciation expenses	(576,138)		(523,341)	(521,311)
Purchase of property, plant and equipment	1,553,475		803,693	548,063
Continuing operations [member] \| Operating segments [member] \| Assembly [member] \| External [member]
Revenue
Revenue	7,963,714		6,001,964	5,148,877
Continuing operations [member] \| Operating segments [member] \| LCDD [member]
Revenue
Revenue	8,211,099		7,023,003	6,922,205
Operating profit (loss)	2,336,394		1,687,986	1,740,720
Depreciation expenses	(2,579,150)		(2,213,504)	(1,796,951)
Purchase of property, plant and equipment	2,748,697		2,143,401	3,077,806
Continuing operations [member] \| Operating segments [member] \| LCDD [member] \| External [member]
Revenue
Revenue	8,211,099		7,023,003	6,922,205
Continuing operations [member] \| Operating segments [member] \| Bumping [member]
Revenue
Revenue	5,325,622		4,983,684	4,008,999
Operating profit (loss)	561,642		487,323	232,404
Depreciation expenses	(549,020)		(578,890)	(604,553)
Purchase of property, plant and equipment	408,751		298,834	506,635
Continuing operations [member] \| Operating segments [member] \| Bumping [member] \| External [member]
Revenue
Revenue	5,325,622		4,983,684	4,008,999
Continuing operations [member] \| Operating segments [member] \| Others [member]
Revenue
Revenue	43,808		39,646	32,808
Operating profit (loss)	(6,987)		(10,230)	1,931
Depreciation expenses	(7,805)		(5,955)	(6,359)
Share of profit (loss) of associates	1,211,177		(320,578)	(370,351)
Interest income	9,980		27,778	64,368
Interest expense	(120,998)		(162,400)	(171,075)
Purchase of property, plant and equipment	420		483	47
Continuing operations [member] \| Operating segments [member] \| Others [member] \| Intersegment [member]
Revenue
Revenue	43,808		39,646	32,808
Continuing operations [member] \| Elimination [member]
Revenue
Revenue	(43,808)		(39,646)	(32,808)
Operating profit (loss)	15		11	18
Share of profit (loss) of associates	(585,444)		173,249	215,425
Continuing operations [member] \| Elimination [member] \| Intersegment [member]
Revenue
Revenue	$ (43,808)		$ (39,646)	$ (32,808)

Segment Information - Schedule of Information on Products and Services (Detail) $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)	Dec. 31, 2019 TWD ($)
Disclosure of products and services [line items]
Net revenue	$ 27,400,035	$ 987,745	$ 23,011,381	$ 20,337,881
Percentage of total revenue	100.00%	100.00%	100.00%	100.00%
Testing [member]
Disclosure of products and services [line items]
Net revenue	$ 5,899,600		$ 5,002,730	$ 4,257,800
Percentage of total revenue	22.00%	22.00%	22.00%	21.00%
Assembly [member]
Disclosure of products and services [line items]
Net revenue	$ 7,963,714		$ 6,001,964	$ 5,148,877
Percentage of total revenue	29.00%	29.00%	26.00%	25.00%
LCDD [member]
Disclosure of products and services [line items]
Net revenue	$ 8,211,099		$ 7,023,003	$ 6,922,205
Percentage of total revenue	30.00%	30.00%	30.00%	34.00%
Bumping [member]
Disclosure of products and services [line items]
Net revenue	$ 5,325,622		$ 4,983,684	$ 4,008,999
Percentage of total revenue	19.00%	19.00%	22.00%	20.00%

The income arising in the course of an entity's ordinary activities. Income is increases in assets, or decreases in liabilities, that result in increases in equity, other than those relating to contributions from holders of equity claims.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2021-01-01
-Paragraph 28
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2021-en-r&anchor=para_28_a&doctype=Standard
-URIDate 2021-03-24

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2021-01-01
-Paragraph 23
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2021-en-r&anchor=para_23_a&doctype=Standard
-URIDate 2021-03-24

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2021-01-01
-Paragraph 32
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2021-en-r&anchor=para_32&doctype=Standard
-URIDate 2021-03-24

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2021-01-01
-Paragraph 33
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2021-en-r&anchor=para_33_a&doctype=Standard
-URIDate 2021-03-24

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2021-01-01
-Paragraph 34
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2021-en-r&anchor=para_34&doctype=Standard
-URIDate 2021-03-24

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2021-01-01
-Paragraph 82
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_82_a&doctype=Standard
-URIDate 2021-03-24

Reference 7: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2021-01-01
-Paragraph 103
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_103&doctype=Standard
-URIDate 2021-03-24

Reference 8: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2021-01-01
-Paragraph 102
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_102&doctype=Standard
-URIDate 2021-03-24

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 5
-IssueDate 2021-01-01
-Paragraph 33
-Subparagraph b
-Clause i
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2021-en-r&anchor=para_33_b_i&doctype=Standard
-URIDate 2021-03-24

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2021-01-01
-Paragraph B12
-Subparagraph b
-Clause v
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2021-en-r&anchor=para_B12_b_v&doctype=Appendix&subtype=B
-URIDate 2021-03-24

Reference 11: http://www.xbrl.org/2003/role/exampleRef
-Name IFRS
-Number 12
-IssueDate 2021-01-01
-Paragraph B10
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2021-en-r&anchor=para_B10_b&doctype=Appendix&subtype=B
-URIDate 2021-03-24

+ Details

Segment Information - Geographic Information of Revenue (Detail) $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)	Dec. 31, 2019 TWD ($)
Disclosure of geographical areas [Line Items]
Revenue	$ 27,400,035	$ 987,745	$ 23,011,381	$ 20,337,881
ROC [member]
Disclosure of geographical areas [Line Items]
Revenue	21,608,567		18,341,726	15,875,027
Japan [member]
Disclosure of geographical areas [Line Items]
Revenue	1,768,460		1,291,026	1,905,032
Singapore [member]
Disclosure of geographical areas [Line Items]
Revenue	1,630,733		1,838,394	1,333,114
People's Republic of China ("PRC") [member]
Disclosure of geographical areas [Line Items]
Revenue	1,899,362		1,105,535	789,496
Others [member]
Disclosure of geographical areas [Line Items]
Revenue	$ 492,913		$ 434,700	$ 435,212

+ References

+ Details

Segment Information - Schedule of Geographical Information (Detail) - TWD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Non-current assets [abstract]
Total non-current assets	$ 21,512,896	$ 18,925,463
ROC [member]
Non-current assets [abstract]
Total non-current assets	21,506,565	18,913,501
PRC [member]
Non-current assets [abstract]
Total non-current assets	86	117
Others [Member]
Non-current assets [abstract]
Total non-current assets	$ 6,245	$ 11,845

Segment Information - Net Revenue from Customers Representing at Least 10% of Total Revenue (Detail) $ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 TWD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 TWD ($)	Dec. 31, 2019 TWD ($)
Disclosure of major customers [Line Items]
Net revenue	$ 27,400,035	$ 987,745	$ 23,011,381	$ 20,337,881
Percentage of total revenue	100.00%	100.00%	100.00%	100.00%
Customer A [member]
Disclosure of major customers [Line Items]
Net revenue	$ 5,681,277		$ 5,088,544	$ 4,756,755
Percentage of total revenue	21.00%	21.00%	22.00%	23.00%
Customer M [Member]
Disclosure of major customers [Line Items]
Net revenue	$ 2,832,088		$ 1,674,801	$ 1,259,269
Percentage of total revenue	10.00%	10.00%	7.00%	6.00%
Customer K [member]
Disclosure of major customers [Line Items]
Net revenue	$ 2,519,631		$ 2,332,914	$ 2,419,612
Percentage of total revenue	9.00%	9.00%	10.00%	12.00%
Customer B [Member]
Disclosure of major customers [Line Items]
Net revenue	$ 2,484,611		$ 2,365,945	$ 1,679,344
Percentage of total revenue	9.00%	9.00%	10.00%	8.00%
Customer C [member]
Disclosure of major customers [Line Items]
Net revenue	$ 2,268,439		$ 2,143,130	$ 2,048,260
Percentage of total revenue	8.00%	8.00%	9.00%	10.00%