Exhibit 99.34

CERTIFICATION PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

(18 U.S.C. SECTION 1350)

In connection with the accompanying Annual Report of Credence Systems Corporation (the “Company”), on Form 10-K for the year ended October 31, 2002 as filed with the Securities and Exchange Commission (the “Report”), I, Graham J. Siddall, Chairman of the Board and Chief Executive Officer of the Company, certify, pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 (18 U.S.C. Section 1350), that to my knowledge:

(1)    The Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

(2)    The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/    GRAHAM J. SIDDALL

Graham J. Siddall

Chairman of the Board and

Chief Executive Officer

January 28, 2003