Exhibit 99.19

                          CREDENCE SYSTEMS CORPORATION
                               215 Fourier Avenue
                                Fremont, CA 94539

                                 March 31, 1999




Mr. Dennis P. Wolf

Dear Dennis:

We are pleased to inform you that the Company's  Board of Directors has approved
a  special  severance  benefit  program  for you.  The  purpose  of this  letter
agreement is to set forth the terms and  conditions of your  severance  benefits
and to explain the limitations that will govern their overall value.

Your severance  package will become  payable  should the Company  terminate your
employment,  or should you  otherwise  resign from the  Company,  under  certain
circumstances  following a  substantial  change in  ownership  or control of the
Company or upon the appointment of a new permanent Chief Executive  Officer.  To
understand the full scope of your benefits, you should familiarize yourself with
the definitional  provisions of Part One of this letter agreement.  The benefits
comprising  your  severance  package  are  detailed  in Part  Two,  and  certain
restrictions  applicable to your benefits are specified in Part Three. Part Four
sets forth the dollar  limitation which will govern your total severance package
in the event your  termination  occurs in connection with a change in control or
ownership of the Company.  Part Five deals with ancillary matters affecting your
severance arrangement.

                             Part One -- DEFINITIONS
                             -----------------------

For purposes of this letter  agreement,  the  following  definitions  will be in
effect:

Average  Compensation  means the  average of your W-2 wages from the Company for
the five  (5)  calendar  years  (or  such  fewer  number  of  calendar  years of
employment with the Company) completed immediately prior to the calendar year in
which a Change in  Control  is  effected.  Any W-2  wages for a partial  year of
employment will be annualized, in accordance with the frequency which such wages
are  paid  during  such  partial   year,   before   inclusion  in  your  Average
Compensation.

Base Salary means the monthly rate of base salary in effect for you  immediately
prior to the Change in Control or Change in Management  (as  applicable)  or (if
greater)  the  monthly  rate  of  base  salary  in  effect  at the  time of your
Involuntary Termination.

Board means the Company's Board of Directors.

Change in Control  means a change in the  ownership  or  control of the  Company
effected through any of the following transactions:

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                           (i)  a  merger  or  consolidation   approved  by  the
                  Company's  stockholders  in which  securities  possessing more
                  than fifty percent (50%) of the total combined voting power of
                  the Company's  outstanding  securities  are  transferred  to a
                  person or persons  different  from the persons  holding  those
                  securities immediately prior to such transaction;

                           (ii) any stockholder-approved sale, transfer or other
                  disposition  of all  or  substantially  all  of the  Company's
                  assets in complete liquidation or dissolution of the Company;

                           (iii) the acquisition, directly or indirectly, by any
                  person or related group of persons  (other than the Company or
                  a person that directly or indirectly  controls,  is controlled
                  by or is under common control with, the Company) of beneficial
                  ownership  (within the meaning of Rule 13d-3 of the Securities
                  Exchange  Act of 1934,  as amended) of  securities  possessing
                  more than fifty  percent  (50%) of the total  combined  voting
                  power of the Company's  outstanding  securities  pursuant to a
                  tender  or  exchange  offer  made  directly  to the  Company's
                  stockholders; or

                           (iv) a change in the  composition of the Board over a
                  period of thirty-six (36) consecutive months or less such that
                  a majority of the Board  members  ceases,  by reason of one or
                  more contested elections for Board membership, to be comprised
                  of  individuals   who  either  (A)  have  been  Board  members
                  continuously  since the  beginning  of such period or (B) have
                  been elected or nominated for election as Board members during
                  such  period  by at  least a  majority  of the  Board  members
                  described  in clause  (A) who were still in office at the time
                  the Board approved such election or nomination.

Change in Management means the appointment by the Board of a new permanent Chief
Executive Officer.

Code means the Internal Revenue Code of 1986, as amended.

Common Stock means the Company's common stock.

Company means  Credence  Systems  Corporation,  a Delaware  corporation,  or any
successor corporation, whether or not resulting from a Change in Control.

Disability  means your  inability to perform the normal and usual duties of your
position with the Company by reason of any physical or medical  impairment which
is  expected  to  result  in  death or  continue  for a period  of  twelve  (12)
consecutive months or more.

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                                                                               3

Fair Market Value means,  with respect to the shares of Common Stock  subject to
any of your Options,  the closing selling price per share of Common Stock on the
date in  question,  as such price is reported  by the  National  Association  of
Securities Dealers on the Nasdaq National Market. If there is no closing selling
price  reported  for the  Common  Stock on the date in  question,  then the Fair
Market Value will be the closing  selling price on the last  preceding  date for
which such report exists.

Health Care Coverage  means the continued  health care coverage to which you and
your eligible  dependents may be entitled during any Salary  Continuation Period
in effect for you under this letter agreement.

Involuntary Termination means (i) the involuntary termination of your employment
with the  Company  other  than a  Termination  for Cause or (ii) your  voluntary
resignation  within ninety (90) days following (A) a material  reduction in your
duties and  responsibilities  as Executive  Vice  President and Chief  Financial
Officer  of the  Company  or (B) a  material  reduction  in your  level  of cash
compensation    (rate   of   Base   Salary   plus   target   bonus   under   any
corporate-performance based bonus or incentive programs) or (C) the consummation
date of a Change of  Control  pursuant  to which a  comparable  position  in the
Company is not offered to you by the  acquiring  entity in the Change of Control
transaction.

In no event shall any of the  following  constitute  grounds  for a  resignation
qualifying as an Involuntary Termination under this letter agreement:

         - a change or other alteration in your duties which occurs by reason of
the Company's  conversion from a public company into a subsidiary or division of
the  acquiring  entity in a Change in  Control  transaction  but which  does not
otherwise materially affect your day-to-day functions; or

         - a general  reduction  in the level of base  salary or target  bonuses
payable to the  executive  officers  of the  Company  which is applied to all or
substantially all of the Company's  executive officers in connection with a cost
reduction program .

In addition, an Involuntary Termination will not be deemed to occur in the event
your  employment  terminates  by  reason  of  your  death  or  Disability  or  a
Termination  for  Cause or in the  event  the  acquiring  entity  in a Change in
Control  transaction offers you a position  comparable to your position with the
Company immediately prior to the Change in Control and at substantially the same
level of cash compensation.

Life  Insurance  Coverage  means  the  continued  coverage  to which  you may be
entitled  under the Company's  group-term  and executive  life  insurance  plans
during  any  Salary  Continuation  Period in effect  for you under  this  letter
agreement.

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                                                                               4

Option means any option  granted to you under the Plan which is  outstanding  at
the time of the Change in Control or Change in  Management  (as  applicable)  or
upon your  subsequent  Involuntary  Termination.  In connection with a Change in
Control,  your  Options  will be divided  into two (2)  separate  categories  as
follows:


          Acquisition-Accelerated    Options:   any   outstanding   Option   (or
     installment  thereof)  which  automatically  accelerates,  pursuant  to the
     acceleration  provisions of the agreement  evidencing  that Option,  upon a
     Change in Control.

          Severance-Accelerated  Options: any outstanding Option (or installment
     thereof) which, pursuant to Part Two of this letter agreement,  accelerates
     upon your Involuntary Termination following the Change in Control.

Option  Parachute  Payment  means,  with respect to any  Acquisition-Accelerated
Option or any Severance-Accelerated Option, the portion of that Option deemed to
be a parachute  payment  under Code Section  280G and the  Treasury  Regulations
issued thereunder.  The portion of such Option which is categorized as an Option
Parachute Payment will be calculated in accordance with the valuation provisions
established under Code Section 280G and the applicable Treasury  Regulations and
will  include an  appropriate  dollar  adjustment  to reflect  the lapse of your
obligation  to remain in the  Company's  employ as a condition to the vesting of
the accelerated  installment.  In no event,  however,  will the Option Parachute
Payment    attributable    to    any    Acquisition-Accelerated     Option    or
Severance-Accelerated Option (or accelerated installment) exceed the spread (the
excess of the Fair Market Value of the accelerated option shares over the option
exercise price payable for those shares) existing at the time of acceleration.

Other Parachute  Payment means any payment in the nature of compensation  (other
than the  benefits  to which you become  entitled  under Part Two of this letter
agreement)  which are made to you in  connection  with the Change in Control and
which  accordingly  qualify as  parachute  payments  within the  meaning of Code
Section 280G(b)(2) and the Treasury  Regulations  issued thereunder.  Your Other
Parachute Payment will include (without limitation) the Present Value,  measured
as of  the  Change  in  Control,  of  the  aggregate  Option  Parachute  Payment
attributable to your Acquisition-Accelerated Options (if any).

Parachute  Payment  means any payment or benefit  provided you under Part Two of
this letter  agreement in  connection  with a Change in Control  (other than the
Option Parachute  Payment  attributable to your  Severance-Accelerated  Options)
which is deemed to  constitute  a parachute  payment  within the meaning of Code
Section 280G(b)(2) and the Treasury Regulations issued thereunder.

Plan means (i) the Company's 1993 Stock Option Plan, as amended or restated from
time  to  time,  and  (ii)  any  successor  stock  incentive  plan  subsequently
implemented by the Company.

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                                                                               5

Present  Value  means  the  value,  determined  as of the date of the  Change in
Control,  of any  payment  in the  nature of  compensation  to which you  become
entitled in connection with the Change in Control or your subsequent Involuntary
Termination,   including  (without  limitation)  the  Option  Parachute  Payment
attributable to your Severance-Acceleration  Options, the additional benefits to
which you become entitled under Part Two of this letter agreement and the Option
Parachute  Payment  attributable to your  Acquisition-Accelerated  Options.  The
Present Value of each such payment will be  determined  in  accordance  with the
provisions  of Code Section  280G(d)(4),  utilizing a discount rate equal to one
hundred twenty  percent  (120%) of the applicable  federal rate in effect at the
time of such  determination,  compounded  semi-annually to the effective date of
the Change in Control or Change. Salary Continuation Period means the period for
which the payment of your Base  Salary may,  pursuant to Part Two of this letter
agreement,  be continued following an Involuntary Termination of your employment
within a specified  period following a Change in Control or Change in Management
(as applicable).

Termination for Cause means the Company's termination of your employment for any
of the following reasons: (i) your commission of any act of fraud,  embezzlement
or dishonesty,  (ii) your  unauthorized use or disclosure of any confidential or
proprietary  information of the Company, (iii) any intentional misconduct by you
which has a materially  adverse effect upon the Company's business or reputation
or (iv) your  continued  failure  to perform  the major  duties,  functions  and
responsibilities  of your position  after you have received  written notice from
the Company identifying the deficiencies in your performance and have been given
a reasonable opportunity to cure those deficiencies, if curable.

                          Part Two - SEVERANCE BENEFITS
                          -----------------------------

Should your  employment  with the Company  terminate by reason of an Involuntary
Termination  within  twelve (12)  months  after a Change in Control or Change in
Management,  then you will become  entitled to receive  the  severance  benefits
provided  under this Part Two.  However,  those  benefits will be subject to the
restrictive covenants of Part Three of this letter agreement and will be in lieu
of all other  severance  benefits to which you might  otherwise be entitled upon
such termination of your employment. In addition, any severance benefits paid to
you in connection with an Involuntary  Termination following a Change in Control
will be subject to the dollar limitation of Part Four.

1.            Accelerated Vesting.

          (a) Change in  Management.  Should  your  employment  with the Company
     terminate by reason of an Involuntary Termination within twelve (12) months
     after a Change in  Management,  then a portion of each  outstanding  Option
     which you hold at the time of your Involuntary  Termination,  to the extent
     not  otherwise  exercisable  for all the shares of Common Stock  subject to


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     that Option,  will immediately  become  exercisable on an accelerated basis
     and  may  be  exercised  for  any or all of  the  shares  subject  to  that
     accelerated  portion until the earlier of (i) the  expiration of the option
     term or (ii) the end of the three  (3)-month  period  following the date of
     your Involuntary Termination.  The number of option shares which shall vest
     and become  exercisable  upon such an accelerated  basis in connection with
     such  Involuntary  Termination  shall be equal to the  number of shares for
     which the Option would have become  exercisable under the Exercise Schedule
     in effect for that Option had you remained in the  Company's  employ for an
     additional  twelve (12) month  period after such  Involuntary  Termination.
     However, to the extent any Option is not exercisable for one or more shares
     at the time of your Involuntary Termination,  after taking into account the
     acceleration  provided under this  paragraph,  the Option will  immediately
     terminate with respect to those shares.

          (b)  Change  in  Control.  Should  your  employment  with the  Company
     terminate by reason of an Involuntary Termination within twelve (12) months
     after a Change in Control,  each  outstanding  Option which you hold at the
     time  of  your  Involuntary  Termination,   to  the  extent  not  otherwise
     exercisable for all the shares of Common Stock subject to that Option, will
     immediately  become  exercisable  for all those  option  shares  and may be
     exercised  for any or all of those shares as fully vested  shares until the
     earlier of (i) the  expiration  of the  option  term or (ii) the end of the
     three (3)-month period following the date of your Involuntary Termination.

2.            Severance Payment.

You will be entitled to salary continuation  payments at your applicable rate of
Base Salary for a Salary Continuation Period of twelve (12) months. These salary
continuation  payments  will be made to you in  accordance  with  the  Company's
normal payroll practices and will be subject to the Company's  collection of all
applicable federal and state income and employment withholding taxes.

3.            Health Care Coverage.

Should you elect continued health care coverage under the Company's medical plan
pursuant to your rights under Code  Section  4980B  ("COBRA"),  the Company will
provide  such  COBRA  coverage,   without  charge,  to  you  and  your  eligible
dependents.  Such  Company-paid  coverage will continue until the earlier of (i)
the  expiration  of your  Salary  Continuation  Period or (ii) the first date on
which you are covered under another  employer's  health benefit  program without
exclusion for any pre-existing  medical  condition.  Any additional  health care
coverage to which you and your  dependents may be entitled under COBRA following
the period of such Company-paid coverage will be at your sole cost and expense.

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4.            Life Insurance Coverage.

You  will  be  entitled  to  Life  Insurance  Coverage  through  your  continued
participation  in the Company's  group term and executive life  insurance  plans
following  your  Involuntary  Termination,  and the Company  will pay the entire
premium charged for such continued Life Insurance  Coverage.  Such  Company-paid
coverage  will continue  until the earlier of (i) the  expiration of your Salary
Continuation  Period  or (ii) the  first  date on which  you are  provided  with
comparable coverage under another employer's life insurance plan.  However,  you
will be  responsible  for the  satisfaction  of any  income and  employment  tax
liability  attributable  to your  Company-paid  Life  Insurance  Coverage.  Your
payments  and  benefits  under  Paragraphs  2, 3 and 4 of  this  Part  Two  will
immediately  terminate  in the  event  you  fail  to  abide  by the  restrictive
covenants set forth in Part Three of this letter agreement.  In addition,  those
payments and benefits  will be subject to the dollar  limitation of Part Four of
this letter agreement in the event of your Involuntary  Termination  following a
Change in Control.

                        Part THREE -- CONSULTING SERVICES
                        AND SPECIAL RESTRICTIVE COVENANTS
                        ---------------------------------

1.            Consulting Services.

In  consideration  for the  salary  continuation  payments  to which you  become
entitled  under Part Two,  you will make  yourself  available  during the Salary
Continuation  Period to render such  consulting  services to the Company  within
your area of expertise as may  reasonably  be requested by the  Company's  Chief
Executive Officer, but in no event may more than ten (10) hours of such services
will be required of you per month.

2.            Cessation of Benefits.

Your Salary  Continuation  Period  will  immediately  terminate,  and all salary
continuation  payments and Company-paid  Health Care Coverage and Life Insurance
Coverage will immediately cease, should you:

          (a)  own,  manage,  operate,  join,  control  or  participate  in  the
     ownership,  management,  operation  or  control  of, or be  employed  by or
     connected  in any  manner  with,  any  enterprise  which is  engaged in any
     business  competitive  with or  similar to that of the  Company;  provided,
     however,  that such  restriction  will not apply to any passive  investment
     representing  an interest of less than one percent  (1%) of an  outstanding
     class of publicly-traded securities of any corporation or other enterprise;

          (b) encourage or solicit any of the  Company's  employees to leave the
     Company's  employ  for any reason or  interfere  in any other  manner  with


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                                                                               8

     employment  relationships  at the time existing between the Company and its
     employees; or

          (c)  induce  any  of  the  Company's  clients,  customers,  suppliers,
     vendors,  distributors,  licensors or licensees to terminate their existing
     business  relationships  with the Company or  interfere in any other manner
     with any existing business relationship between the Company and any client,
     customer, supplier, vendor, distributor,  licensor, licensee or other third
     party.

                       Part FOUR -- LIMITATION ON BENEFITS
                       -----------------------------------

The benefit  limitation of this Part Four shall be applicable only to the extent
the payments and benefits  made to you pursuant to Paragraphs 2, 3 and 4 of Part
Two are  attributable  to your  Involuntary  Termination  following  a Change in
Control.

1.            Benefit Limit.

The  aggregate  Present  Value  (measured  as of the Change in  Control)  of the
benefits  to  which  you  become  entitled  under  Part  Two at the time of your
Involuntary  Termination,  namely, the salary continuation  payments, the Option
Parachute Payment  attributable to your  Severance-Accelerated  Options and your
Company-paid Health Care Coverage and Life Insurance Coverage,  will in no event
exceed in amount the  greater of the  following  dollar  amounts  (the  "Benefit
Limit"):

          (a) 2.99 times your  Average  Compensation,  less the  Present  Value,
     measured as of the Change in Control,  of all Other  Parachute  Payments to
     which you are entitled, or

          (b) the amount  which  yields  you the  greatest  after-tax  amount of
     benefits under Part Two of this letter  agreement after taking into account
     any excise tax imposed under Code Section 4999 on the payments and benefits
     which are provided you under Part Two or which  constitute  Other Parachute
     Payments.

The Option  Parachute  Payment  attributable to the accelerated  vesting of your
Acquisition-Accelerated  Options at the time of the Change in Control shall also
be subject to the Benefit  Limitation.  However, no other terms or provisions of
your Acquisition-Accelerated Options shall be affected by this letter agreement.

2.            Resolution Procedure.

In the event there is any disagreement between you and the Company as to whether
one or more payments to which you become  entitled in connection with either the
Change  in  Control  or  your  subsequent  Involuntary   Termination  constitute
Parachute Payments,  Option Parachute Payments or Other Parachute Payments or as

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to the determination of the Present Value of any of those payments, such dispute
will be resolved as follows:

          (i) In the event temporary,  proposed or final Treasury Regulations in
     effect  at the  time  under  Code  Section  280G  (or  applicable  judicial
     decisions)  specifically  address  the  status of any such  payment  or the
     method of valuation therefor, the characterization afforded to such payment
     by the Regulations (or such decisions)  will,  together with the applicable
     valuation methodology, be controlling.

          (ii)  In  the  event  Treasury  Regulations  (or  applicable  judicial
     decisions) do not address the status of any payment in dispute,  the matter
     will be  submitted  for  resolution  to  independent  tax counsel  mutually
     acceptable to you and the Company ("Independent  Counsel").  The resolution
     reached by  Independent  Counsel will be final and  controlling;  provided,
     however,  that  if  in  the  judgment  of  Independent  Counsel  the status
     of the  payment in dispute  can be resolved  through  the  obtainment  of a
     private  letter  ruling from the  Internal  Revenue  Service,  a formal and
     proper   request  for  such  ruling  will  be  prepared  and  submitted  by
     Independent  Counsel,  and the  determination  made by the Internal Revenue
     Service in the issued ruling will be controlling.  All expenses incurred in
     connection  with the retention of Independent  Counsel and (if  applicable)
     the preparation and submission of the ruling request will be shared equally
     by you and the Company.

          (iii)     In the event Treasury  Regulations (or  applicable  judicial
     decisions) do not address the  appropriate  valuation  methodology  for any
     payment in dispute,  the Present Value  thereof  will,  at the  Independent
     Counsel's  election,  be  determined  through  an  independent  third-party
     appraisal,  and the expenses  incurred in obtaining  such appraisal will be
     shared equally by you and the Company.

3.            Status of Benefits.

          A. No  benefits  shall be  provided  you under Part Two of this letter
     agreement  (including the accelerated vesting of your outstanding  Options,
     the salary continuation  payments and the Company-paid Health Care Coverage
     and  Life  Insurance  Coverage)  until  the  Present  Value  of the  Option
     Parachute Payment attributable to both your  Severance-Accelerated  Options
     and your Acquisition-Accelerated Options has been determined and the status
     of any  payments in dispute  under  Paragraph 2 above has been  resolved in
     accordance  therewith.  The post-service exercise period in effect for your
     Options  shall be stayed  and shall  not run until the  resolution  process
     hereunder is completed.

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          B. Once the requisite determinations under Paragraph 2 have been made,
     then to the extent the aggregate  Present Value,  measured as of the Change
     in  Control,  of (i) the  Option  Parachute  Payment  attributable  to your
     Severance-Accelerated  Options  (or  installments  thereof)  plus  (ii) the
     Parachute  Payment  attributable to your other benefit  entitlements  under
     Part Two of this letter agreement would, when added to the Present Value of
     all your Other Parachute  Payments  (including the Option Parachute Payment
     attributable to your  Acquisition-Accelerated  Options), exceed the Benefit
     Limit, your salary  continuation  payments will first be reduced,  and then
     the period of your  Company-paid  Health Care  Coverage and Life  Insurance
     Coverage  will be  shortened,  to the extent  necessary to assure that such
     Benefit Limit is not exceeded.

                            Part Five - MISCELLANEOUS
                            -------------------------

1.            Termination for Cause.

Should your employment  cease by reason of a Termination for Cause or should you
depart  or  voluntarily  resign  under   circumstances   which  would  otherwise
constitute  grounds for a Termination  for Cause,  then the Company will only be
required to pay you (i) any unpaid  compensation  earned for services previously
rendered  through the date of such  termination  and (ii) any accrued but unpaid
vacation  benefits or sick days,  and no  benefits  will be payable to you under
Part Two of this letter agreement.

2.            Death.

Should you die before  receipt of one or more  salary  continuation  payments to
which you become entitled under this letter agreement,  then those payments will
be made to the executors or administrators of your estate. Should you die before
you exercise all your outstanding  Options as accelerated  hereunder,  then such
Options may be  exercised,  within  twelve (12) months after your death,  by the
executors or administrators of your estate or by persons to whom the Options are
transferred pursuant to your will or in accordance with the laws of inheritance.
In no event,  however,  may any such  Option be  exercised  after the  specified
expiration date of the option term.

3.            General Creditor Status.

All cash payments to which you become entitled hereunder will be paid, when due,
from the general assets of the Company, and no trust fund, escrow arrangement or
other  segregated  account  will be  established  as a funding  vehicle for such
payment.  Accordingly,  your right (or the right of the personal representatives
or beneficiaries of your estate) to receive such cash payments hereunder will at
all times be that of a general creditor of the Company and will have no priority
over the claims of other general creditors.

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                                                                              11

4.            Indemnification.

To  the  maximum  extent  permitted  by  applicable  law,  the   indemnification
provisions for Officers and Directors  under the Company By-Laws and Certificate
of  Incorporation  and pursuant to contract will be extended to you,  during the
period  following  your  Involuntary  Termination,  with  respect to any and all
matters,  events or  transactions  occurring or effected  during your employment
with the Company.

5.            Miscellaneous.

This letter  agreement  will be binding upon the  Company,  its  successors  and
assigns (including,  without  limitation,  the surviving entity in any Change in
Control) and is to be construed and  interpreted  under the laws of the State of
California.  This letter agreement  supersedes all prior agreements  between you
and the Company  relating to the subject of  severance  benefits  payable upon a
change in control or ownership of the Company or a change in management, and you
will not be entitled to any other  severance  benefits  upon such a  termination
other than those that are provided in this letter agreement or your stock option
agreements and the Plan. This letter  agreement  specifically  supersedes  those
provisions of the employee  offer letter  agreement  dated March 13, 1998 by and
between the Company and you as such  provisions  relate to the subject matter of
this letter  agreement.  This  letter may only be amended by written  instrument
signed by you and an authorized officer of the Company. If any provision of this
letter agreement as applied to you or the Company or to any circumstance  should
be adjudged by a court of competent jurisdiction to be void or unenforceable for
any  reason,  the  invalidity  of that  provision  will in no way affect (to the
maximum  extent  permissible by law) the  application  of such  provision  under
circumstances  different from those adjudicated by the court, the application of
any  other  provision  of  this  letter  agreement,  or  the  enforceability  or
invalidity  of this letter  agreement as a whole.  Should any  provision of this
letter  agreement  become or be deemed invalid,  illegal or unenforceable in any
jurisdiction  by reason of the scope,  extent or duration of its coverage,  then
such  provision  will be deemed  amended to the extent  necessary  to conform to
applicable law so as to be valid and enforceable or, if such provision cannot be
so amended without materially  altering the intention of the parties,  then such
provision  will be stricken  and the  remainder  of this letter  agreement  will
continue in full force and effect.

6.            At Will Employment.

Nothing in this  letter  agreement  is intended to provide you with any right to
continue  in the employ of the  Company  (or any  subsidiary)  for any period of
specific duration or interfere with or otherwise restrict in any way your rights
or the  rights of the  Company  (or any  subsidiary),  which  rights  are hereby
expressly reserved by each, to terminate your employment at will or as otherwise
specified in your employment contract.

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                                                                              12

Please indicate your acceptance of the foregoing by signing the enclosed copy of
this letter and returning it to the Company.

                                Very truly yours,

                                CREDENCE SYSTEMS CORPORATION


                          By:         /s/ Dr. William G. Howard
                                      ------------------------------------------

                          Title:      Chairman
                                      ------------------------------------------



                                   ACCEPTANCE

I hereby agree to all the terms and provisions of the foregoing letter agreement
governing  the  special  benefits  to  which  I  may  become  entitled  upon  an
involuntary  termination of my employment,  or my voluntary  resignation,  under
certain prescribed  circumstances  following a change in control or ownership of
the Company or the appointment of a new permanent Chief Executive Officer of the
Company.  I also have had an  opportunity  to  consult  with my own  counsel.  I
acknowledge  that  Brobeck,  Phleger &  Harrison  LLP  serves as  counsel to the
Company with respect to the foregoing letter agreement.

                           Signature:          /s/ Dennis P. Wolf
                           -----------------------------------------------------

                           Dated:              3/31/99
                           -----------------------------------------------------




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