EXHIBIT 99.8

                                                  EFFECTIVE DATE: AUGUST 1, 2001


                          CREDENCE SYSTEMS CORPORATION
                        STOCK OPTION ASSUMPTION AGREEMENT

Dear (Name):

As you know, on August 1, 2001 (the "Closing Date") Credence Systems Corporation
("Credence") acquired Integrated Measurement Systems, Inc. ("IMS") (the
"Acquisition"). In the Acquisition, each share of IMS common stock was exchanged
for 0.9 of a share of Credence common stock (the "Exchange Ratio"). On the
Closing Date you held one or more outstanding options to purchase shares of
Integrated Measurement Systems, Inc. common stock granted to you under the
Integrated Measurement Systems, Inc. ___________ Plan (the "Plan") and
documented with a Stock Option Agreement(s) and/or Notice(s) of Grant of Stock
Option (collectively, the "Option Agreement") issued to you under the Plan (the
"IMS Options"). In accordance with the Acquisition, on the Closing Date Credence
assumed all obligations of IMS under the IMS Options. This Agreement evidences
the assumption of the IMS Options, including the necessary adjustments to the
IMS Options required by the Acquisition.

Your IMS Options immediately before and after the Acquisition are as described
in the information you received from E*Trade.

The post-Acquisition adjustments to your number of shares and exercise price are
based on the Exchange Ratio and are intended to: (i) assure that the total
spread of each assumed IMS Option (i.e., the difference between the aggregate
fair market value and the aggregate exercise price) does not exceed the total
spread that existed immediately prior to the Acquisition; (ii) to preserve, on a
per share basis, the ratio of exercise price to fair market value that existed
immediately prior to the Acquisition; and (iii) to the extent applicable and
allowable by law, to retain incentive stock option ("ISO") status under the
Federal tax laws.

Unless the context otherwise requires, any references in the Plan and the Option
Agreement (i) to the "Company" or the "Corporation" means Credence, (ii) to
"Stock," "Common Stock" or "Shares" means shares of Credence Stock, (iii) to the
"Board of Directors" or the "Board" means the Board of Directors of Credence and
(iv) to the "Committee" means the Compensation Committee of the Credence Board
of Directors. All references in the Option Agreement and the Plan relating to
your status as an employee of IMS will now refer to your status as an employee
of Credence or any present or future Credence subsidiary. To the extent the
Option Agreement allowed you to deliver shares of IMS common stock as payment
for the exercise price, shares of Credence common stock may be delivered in
payment of the adjusted exercise price, and the period for which such shares
were held as IMS Stock prior to the Acquisition will be taken into account.

The grant date, vesting commencement date, vesting schedule and the expiration
date of your assumed IMS Options remain the same as set forth in your Option
Agreement, but the number of



                                                  EFFECTIVE DATE: AUGUST 1, 2001

shares subject to each vesting installment has been adjusted to reflect the
Exchange Ratio. All other provisions which govern either the exercise or the
termination of the assumed IMS Option remain the same as set forth in your
Option Agreement, and the provisions of the Option Agreement (except as
expressly modified by this Agreement and the Acquisition) will govern and
control your rights under this Agreement to purchase shares of Credence Stock.
However, to the extent an item is not explicitly provided for in your option
documents, Credence policies will apply. Upon your termination of employment
with Credence you will have the limited time period specified in your Option
Agreement to exercise your assumed IMS Option to the extent vested and
outstanding at the time, generally a 60 day period, after which time your IMS
Options will expire and NOT be exercisable for Credence Stock.

To exercise your assumed IMS Option, you must deliver to Credence ____________.

Nothing in this Agreement or your Option Agreement interferes in any way with
your rights and Credence's rights, which rights are expressly reserved, to
terminate your employment at any time for any reason. Any future options, if
any, you may receive from Credence will be governed by the terms of the Credence
stock option plan, and such terms may be different from the terms of your
assumed IMS Options, including, but not limited to, the time period in which you
have to exercise vested options after your termination of employment.

Please sign and date this Agreement and return it promptly to the address listed
above. If you have any questions regarding this Agreement or your assumed IMS
Options, please contact ____________ at ______________.

                                                 CREDENCE SYSTEMS CORPORATION

                                                 By:



                                                  EFFECTIVE DATE: AUGUST 1, 2001

                                 ACKNOWLEDGMENT

          The undersigned acknowledges receipt of the foregoing Stock Option
Assumption Agreement and understands that all rights and liabilities with
respect to each of his or her IMS Options hereby assumed by Credence are as set
forth in the Option Agreement, the Plan, and such Stock Option Assumption
Agreement.

DATED: __________________, 2001            ___________________________________
                                          (Name), OPTIONEE