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                                                                   EXHIBIT 10.20

                           CHANGE OF CONTROL AGREEMENT

         This Agreement is made this 23 day of August, 2002 ("Effective Date")
by and between Douglas Raymond (the "Executive") and PDF Solutions, Inc., a
Delaware corporation (the "Company").

         WHEREAS, the Executive will be employed by the Company; and

         WHEREAS, the Company desires to retain the services of Executive in the
event of a change of control (as hereinafter defined) of the Company.

         NOW, THEREFORE, in consideration of the mutual covenants contained
herein, the parties hereto agree as follows:

         1.       Term. This Agreement shall commence as of Executive's Start
Date (the "Effective Date") and shall continue in effect until the fifth
anniversary of the Effective Date; provided that notwithstanding the foregoing
the term of this Agreement shall not expire prior to the expiration of twelve
(12) months after the occurrence of a Change of Control. The term of this
Agreement may be extended only upon mutual written agreement of both parties.

         2.       Definitions.

                  (a)      Change of Control. For purposes of this Agreement
only, a "Change of Control" shall be defined as any of the following events:

                           (i)      An acquisition (other than directly from the
Company) of any voting securities of the Company (the "Voting Securities") by
any "Person" (as the term is used for purposes of Section 13(d) or 14(d) of the
Securities Exchange Act of 1934, as amended (the "1934 Act")) immediately after
which such Person has "Beneficial Ownership" (within the meaning of Rule 13d-3
promulgated under the 1934 Act), directly or indirectly, of securities of the
Company representing fifty percent (50%) or more of the combined voting power of
the Company's then outstanding Voting Securities;

                           (ii)     A merger or consolidation in which the
Company is not the surviving entity, except for (1) a transaction in which the
principal purpose is to change the state of the Company's incorporation, or (2)
a transaction in which the Company's stockholders immediately prior to such
merger or consolidation hold (by virtue of securities received in exchange for
their shares in the Company) securities of the surviving entity representing
more than fifty percent (50%) of the total voting power of such entity
immediately after such transaction;

                           (iii)    The individuals who are members of the
Company's Board of Directors (the "Board") as of the date this Agreement is
approved by the Board (the "Incumbent

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Board") cease for any reason to constitute at least a majority of the Board;
provided, however, that if the appointment, election or nomination for election
by the Company's stockholders, of any new director is approved by a vote of at
least two-thirds of the Incumbent Board, such new director shall, for purposes
of this Agreement, be considered a member of the Incumbent Board; provided
further, however, that no individual shall be considered a member of the
Incumbent Board if such individual initially assumed office as a result of
either an actual or threatened "Election Contest" (as described in Rule 14a-11
promulgated under the 1934 Act) or other actual or threatened solicitation of
proxies or consents by or on behalf of a Person other than the Board (a "Proxy
Contest") including by reason of any agreement intended to avoid or settle any
Election Contest or Proxy Contest;

                           (iv)     The sale, transfer or other disposition of
all or substantially all of the assets of the Company, unless the Company's
stockholders immediately prior to such sale, transfer or other disposition hold
(by virtue of securities received in exchange for their shares in the Company)
securities of the purchaser or other transferee representing more than fifty
percent (50%) of the total voting power of such entity immediately after such
transaction; or

                           (v)      Any reverse merger in which the Company is
the surviving entity but in which the Company's stockholders immediately prior
to such merger do not hold (by virtue of their shares in the Company held
immediately prior to such transaction) securities of the Company representing
more than fifty percent (50%) of the total voting power of the Company
immediately after such transaction.

                  (b)      Cause. For purposes of this Agreement only, the
Company shall have "Cause" to immediately terminate the Executive's employment
hereunder if (i) Executive engages in fraud or embezzlement against the Company
and/or its subsidiaries, (ii) Executive misappropriates Company property,
proprietary information and/or trade secrets, (iii) Executive demonstrates
material unfitness for service or persistent deficiencies in performance, (iv)
Executive engages in misconduct, which misconduct is demonstrably and materially
injurious to the Company and/or its subsidiaries; (v) Executive refuses to
follow a specific, lawful direction or order of the Company; (vi) Executive
breaches any provision of this Agreement or other agreements between Executive
and the Company; or (vii) Executive dies or becomes mentally or physically
incapacitated and cannot carry out his duties.

                  (c)      Voluntary Resignation for Good Reason. A voluntary
resignation by Executive "Good Reason" shall mean a voluntary resignation by
Executive following any one of the following events, provided Executive provides
Company with at least two (2) weeks notice of such termination, and provides
such notice no later than thirty (30) days following any one of the following
events: (i) a material change in Executive's position, title, duties, or
responsibilities, without Employee's consent, which results in a material
reduction of Executive's level of responsibility, the assignment of duties and
responsibilities which are materially inconsistent with Executive's position or
responsibilities, or the removal of the Executive from or failure to reelect the
Executive to any of such positions, except in connection with the termination of
employment for Cause; (ii) a reduction by the Company in the Executive's annual
salary then in effect, without

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Executive's consent, other than a reduction similar in percentage to a reduction
generally applicable to similarly situated employees of the Company; (iii) a
material reduction without the Executive's consent in the kind or level of
benefits provided to Executive under any benefit plan of the Company in which
the Executive is participating or deprive the Executive of any material fringe
benefit enjoyed by the Executive, except those changes generally affecting
similarly situated employees of the Company; or (iv) a relocation of Executive
without his consent to a facility or a location more than 75 miles from
Executive's then current workplace.

                  (d)      Closing Date. "Closing Date" shall mean the date of
the first closing of any transactions constituting a Change of Control.

                  (e)      Termination Date. "Termination Date" shall mean the
date the Executive's employment is terminated by the Company other than for
Cause or is terminated by the Executive for Good Reason.

                  (f)      Company. "Company" shall mean PDF Solutions, Inc. and
its successors or assigns (including without limitation, any entity, entities or
persons acquiring control of the Company through a Change of Control).

                  (g)      Date of Hire. "Date of Hire" shall mean the date
Executive commences full-time employment with the Company.

         3.       Termination of Employment For Cause or By Executive Without
Good Reason. If, following the Closing Date of a Change of Control, the Company
terminates the Executive's employment for Cause or Executive voluntarily resigns
from employment without Good Reason, Executive shall be entitled to all
compensation due and owing to him through the date his employment terminates,
and the Company's obligations hereunder shall cease.

         4.       Termination of Employment Within Six Months Following a Change
of Control. If, following the Closing Date of a Change of Control, the Company
terminates the Executive's employment other than for Cause or if the Executive
voluntarily resigns from employment for Good Reason and such termination or
resignation occurs within six (6) months following a Change of Control, then
Executive shall be entitled to the following:

                  (a)      If Executive's Termination Date is within one year of
his Date of Hire, the restrictions on any outstanding equity incentive awards,
including stock options and restricted stock, granted to the Executive under the
Company's stock option and other stock incentive plans or under any other
incentive plan or arrangement shall lapse such that the incentive award shall
become 50% vested and, in the case of stock options, Company shall accelerate
the vesting Executive's unvested stock options such that 50% of Executive's
outstanding stock options shall be immediately exercisable; or

                  (b)      If Executive's Termination Date is after the one year
anniversary of his Date of Hire, but before the second anniversary of his Date
of Hire, the restrictions on any

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outstanding equity incentive awards, including stock options and restricted
stock, granted to the Executive under the Company's stock option and other stock
incentive plans or under any other incentive plan or arrangement shall lapse
such that the incentive award shall become 50% vested and, in the case of stock
options, Company shall accelerate the vesting of up to 25% of Executive's
unvested stock options such that a total of 50% of Executive's outstanding stock
options shall be immediately exercisable; and

                  (c)      Executive shall receive the severance benefits set
forth in paragraphs 5(a) and (b) below.

         5.       Termination of Employment within Twelve Months Following a
Change of Control. If, following the Closing Date of a Change of Control, the
Company terminates the Executive's employment other than for Cause or the
Executive voluntarily resigns from employment for Good Reason and such
termination or resignation does not occur within six (6) months following the
Closing Date of a Change of Control but occurs within twelve (12) months
following the Closing Date of a Change of Control, then in such event:

                  (a)      Severance Payment. The Company shall pay the
Executive a severance payment equal to seven (7) months' pay at Executive's base
salary in effect as of the Termination Date. Such severance payment shall be
made in the form of a lump sum payment (less applicable withholdings and
deductions) within 30 days of Executive Termination Date or in the form of
salary continuation for a period of seven (7) months following the Termination
Date, at the Company's discretion; and

                  (b)      Medical and Dental Benefits. The Company shall
reimburse the Executive for COBRA payments made by the Executive to maintain his
medical, vision, and dental benefits for a period of up to seven (7) months
following the Termination Date.

                  (c)      Executive shall not be entitled to receive any other
severance benefits, including but not limited to the severance benefits
described in paragraph 4(a) or 4(b), if he receives the benefits provided for in
paragraphs 5(a) and (b).

         6.       No Employment Agreement, Employment at Will. Executive and the
Company each acknowledge and agree that: (i) this Agreement does not provide for
the terms and conditions of Executive's employment with the Company prior to any
Change of Control and does not require or obligate Executive to provide services
to the Company or the Company to continue to employ Executive; and (ii)
Executive's employment with the Company is and remains an employment
relationship terminable at will and without advance notice by either Executive
or the Company.

         7.       Release of the Company and Its Affiliates. Executive's receipt
of the benefits described in paragraph 4 or paragraph 5 above shall be
contingent upon Executive executing a general release of claims in a
commercially customary form prescribed by the Company, which releases and
discharges the Company and any past, present or future agents, attorneys,
directors, officers, stockholders, employees, affiliates, predecessors and
successors of the Company, of and

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from any and all claims and demands of every kind and nature, in law, equity or
otherwise, known or unknown, disclosed or undisclosed, and a covenant not to sue
or prosecute any legal action or proceeding based upon such claims.

         8.       Excise Tax. Notwithstanding anything contained in this
Agreement to the contrary, to the extent that any payment or benefit (within the
meaning of Section 280G(b)(2) of the Internal Revenue Code of 1986, as amended
(the "Code")) to Executive or for Executive's benefit, paid or payable or
distributed or distributable pursuant to the terms of this Agreement or
otherwise in connection with, or arising out of, Executive's employment with the
Company or a Change in Control (a "Payment" or "Payments"), would be subject to
the excise tax imposed under Code Section 4999, or any interest or penalties are
incurred by Executive with respect to such excise tax (such excise tax, together
with any such interest and penalties, are hereinafter collectively referred to
as the "Excise Tax"), the Payments shall be reduced (but not below zero) if and
to the extent necessary so that no Payment to be made or benefit to be provided
to Executive shall be subject to the Excise Tax (such reduced amount is
hereinafter referred to as the "Limited Payment Amount"). Any notice given by
Executive pursuant to the preceding sentence shall take precedence over the
provisions of any other plan, arrangement or agreement governing Executive's
rights and entitlements to any benefits or compensation.

                  (a) An initial determination as to whether the Payments shall
be reduced to the Limited Payment Amount and the amount of such Limited Payment
Amount shall be made, at the Company's expense, by the accounting firm that is
the Company's independent accounting firm as of the date of the Change in
Control (the "Accounting Firm"). The Accounting Firm shall provide its
determination (the "Determination"), together with detailed supporting
calculations and documentation, to the Company and Executive within five (5)
days after the Termination Date, if applicable, or such other time as requested
by the Company or by Executive (provided Executive reasonably believes that any
of the Payments may be subject to the Excise Tax) and, if the Accounting Firm
determines that no Excise Tax is payable by Executive with respect to a Payment
or Payments, it shall furnish Executive with an opinion reasonably acceptable to
Executive that no Excise Tax will be imposed with respect to any such Payment or
Payments. Within ten (10) days after the delivery of the Determination to
Executive, Executive shall have the right to dispute the Determination (the
"Dispute"). If there is no Dispute, the Determination shall be binding, final
and conclusive upon the Company and Executive, subject to the application of
Section 8(b) below.

                  (b) As a result of the uncertainty in the application of
Sections 4999 and 280G of the Code, it is possible that the Payments to be made
to, or provided for the benefit of, Executive will be either greater (an "Excess
Payment") or less (an "Underpayment") than the amounts provided for by the
limitations contained in Section 8.

                           (i)      If it is established, pursuant to a final
determination of a court or an Internal Revenue Service (the "IRS") proceeding
which has been finally and conclusively resolved, that an Excess Payment has
been made, such Excess Payment shall be deemed for all purposes to be a loan to
Executive made on the date Executive received the Excess Payment, which loan
Executive must repay to the Company together with interest at the applicable
federal rate under

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Code Section 7872(f)(2); provided, that no loan shall be deemed to have been
made and no amount will be payable by Executive to the Company unless, and only
to the extent that, the deemed loan and payment would either reduce the amount
on which Executive is subject to tax under Code Section 4999 or generate a
refund of tax imposed under Code Section 4999.

         9.       In the event that it is determined (i) by the Accounting Firm,
the Company (which shall include the position taken by the Company, or together
with its consolidated group, on its federal income tax return) or the IRS, (ii)
pursuant to a determination by a court, or (iii) upon the resolution to
Executive's satisfaction of the Dispute, that an Underpayment has occurred, the
Company shall pay an amount equal to the Underpayment to Executive within ten
(10) days after such determination or resolution, together with interest on such
amount at the applicable federal rate under Code Section 7872(f)(2) from the
date such amount would have been paid to Executive until the date of payment.

         10.      Exclusive Remedy. Executive's right to salary continuation and
other severance benefits pursuant to paragraph 4 or paragraph 5 above shall be
Executive's sole and exclusive remedy for any termination of Executive's
employment by the Company other than for Cause or by Executive for Good Reason
following a Change of Control. The payments, severance benefits and severance
protections provided to Executive pursuant to this Agreement are provided in
lieu of any severance payments, severance benefits and severance protections
provided in any other plan or policy of the Company, except as may be expressly
provided in writing under the terms of any plan or policy of the Company, or in
a written agreement between the Company and Executive entered into after the
date of this Agreement. Notwithstanding the foregoing, nothing in this Agreement
shall prevent or limit Executive's continuing or future participation in any
benefit, bonus, incentive or other plan or program provided by the Company
(except for any severance or termination policies, plans, programs or practices)
and for which Executive may qualify, nor shall anything herein limit or reduce
such rights as Executive may have under any other agreements with the Company
(except for any severance or termination agreement). Amounts which are vested
benefits or which Executive is otherwise entitled to receive under any plan or
program of the Company shall be payable in accordance with such plan or program,
except as explicitly modified by this Agreement.

         11.      Arbitration. The parties hereby agree that any dispute, claim
or controversy arising out of, relating to or in connection with this Agreement
("Arbitrable Claims") shall be determined exclusively by and through final and
binding arbitration in Santa Clara County, California, each party hereto
expressly and conclusively waiving its right to proceed to a judicial
determination with respect to the merits of such arbitrable matters. Such
arbitration shall be conducted in accordance with the American Arbitration
Association National Rules for Resolution of Employment Disputes then in effect
before a neutral and impartial arbitrator who shall be selected by mutual
agreement of the parties. The arbitrator shall prepare a written decision
containing the essential findings and conclusions on which the award is based so
as to ensure meaningful judicial review of the decision. The arbitrator shall
apply the same substantive law, with the same statutes of limitations and same
remedies, that would apply if the claims were brought in a court of law.

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This Agreement shall be governed by the California Arbitration Act and the
arbitrator, in ruling on procedural and substantive issues raised in the
arbitration itself, shall apply the substantive law of the State of California.
Either party may bring an action in court to compel arbitration under this
Agreement and to enforce an arbitration award. Otherwise, neither party shall
initiate or prosecute any lawsuit in any way related to any Arbitrable Claim.
THE PARTIES HEREBY WAIVE ANY RIGHTS THEY MAY HAVE TO TRIAL BY JURY IN REGARD TO
ARBITRABLE CLAIMS.

         12.      Successors. This Agreement shall be binding upon and shall
inure to the benefit of the parties hereto and their respective heirs,
executors, administrators, successors and assigns. Neither this Agreement nor
any right or interest hereunder shall be assignable or transferable by Executive
or Executive's beneficiaries or legal representatives, except by will or by the
laws of descent and distribution. This Agreement shall inure to the benefit of
and be enforceable by Executive's legal personal representative.

         13.      Governing Law. The interpretation, performance and enforcement
of this Agreement shall be governed by the laws of the State of California.

         14.      Entire Agreement. This Agreement represents the entire
Agreement and understanding between the Company and the Executive concerning the
Executive's termination of employment with the Company after a Change in
Control. This Agreement supersedes any prior agreement or understanding of the
parties with respect to the subject matter hereof.

         15.      No Oral Modification. This Agreement may only be amended in a
writing signed by the Executive and the Company.

         16.      Severability. If any provision of this Agreement of the
application thereof to any person, place, or circumstance, shall be held by a
court of competent jurisdiction to be invalid, unenforceable, or voice, the
remainder of this Agreement and such provisions as applied to other persons,
places, and circumstances shall remain in full force and effect.

         17.      Counterparts. This Agreement may be executed in counterparts,
and each counterpart shall have the same force and effect as the original and
shall constitute an effective, binding agreement on the part of each of the
undersigned.

         18.      Attorneys' Fees. If any legal action, arbitration or other
proceeding is brought to interpret or enforce the terms of this Agreement, the
prevailing party shall be entitled to recover reasonable attorneys' fees and any
other costs incurred in that proceeding, in addition to any other relief to
which it is entitled.

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         IN WITNESS WHEREOF, the parties hereto have duly executed this
Agreement as of the date first above written.

PDF SOLUTIONS, INC.                         EXECUTIVE:

By: /s/ John Kibarian                       /s/ Douglas M.Raymond
    --------------------------              ------------------------------------
        John Kibarian                                              8/27/2002
Title: Chief Executive Officer

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