TSMC's Internal Audit function is an independent unit that reports directly to the Board of Directors. Besides informing the Board during its ordinary meetings, it briefs the Chairman, the Board Audit and Risk Committee, and the Operating Committee on a quarterly and on as needed basis.

The charter of Internal Audit is to review the internal controls in the company's processes and to report on those controls with respect to the adequacy, effectiveness, and efficiency of their design as well as their actual functioning on a day-to-day basis. All parts of the company and its subsidiaries are open for review by Internal Audit.

The majority of the audit work is executed according to an annual plan, which needs to be approved by the Board of Directors. Such plan will take into account risks that have been identified. Special audits or reviews are conducted as needed. The combination of the regular audits and the special projects provide management with objective assurance and insight on the functioning of the internal control system; it gives management an additional channel to learn about existing or possible future weaknesses in the system, which allows management to address them in a timely manner.

The company supplements the review activities by Internal Audit with documented self-assessments by the divisions and all subsidiaries. Internal Audit sees to it that these activities do take place, and reviews the submissions to ensure the quality of the process; it consolidates the results of the self-assessments for the Board Audit and Risk Committee and the Board of Directors.

There are 22 full time employees dedicated to Internal Audit, including 1 senior director and 21 staff members. The appointment or dismissal of Head of Internal Audit shall be approved by Audit and Risk Committee and further submitted to the BOD's Meeting for a resolution.