Exhibit 99.1 CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM We consent to the incorporation by reference in the Registration Statements Nos. 333-121865, 333-109817 and 333-98405 on Form S-8 of our report relating to the financial statements of Taiwan Semiconductor Manufacturing Company Limited dated February 27, 2006 appearing in this Annual Report on Form 20-F of Taiwan Semiconductor Manufacturing Company Limited for the year ended December 31, 2005, which expresses an unqualified opinion and includes explanatory paragraphs relating to the reconciliation to accounting principles generally accepted in the United States of America and the convenience translation of New Taiwan Dollar amounts into U.S. dollar amounts. /s/ Deloitte & Touche Deloitte & Touche Taipei, Taiwan The Republic of China April 18, 2006