<PAGE>

                                                                     EXHIBIT 4.2


                             STOCKHOLDERS' AGREEMENT

                                   dated as of

                           _____________________, 2004

                                      among

                           ULTRA CLEAN HOLDINGS, INC.,

                               FP-ULTRA CLEAN, LLC

                                       and

                       CERTAIN OTHER PERSONS NAMED HEREIN

<PAGE>

                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                                 PAGE
                                                                                                 ----
<S>                                                                                              <C>

                                                  ARTICLE 1
                                                 DEFINITIONS

Section 1.01.  Definitions.....................................................................    1

                                                  ARTICLE 2
                                             CORPORATE GOVERNANCE

Section 2.01.  Composition of the Board........................................................    4
Section 2.02.  Removal.........................................................................    5
Section 2.03.  Vacancies.......................................................................    6
Section 2.04.  Action by the Board.............................................................    6
Section 2.05.  Conflicting Charter or Bylaw Provisions.........................................    8
Section 2.06.  Subsidiary Governance...........................................................    9

                                                  ARTICLE 3
                                           RESTRICTIONS ON TRANSFER

Section 3.01.  General.........................................................................    9
Section 3.02.  Legends.........................................................................    9
Section 3.03.  Restrictions on Transfer........................................................   10
Section 3.04.  Permitted Transferees...........................................................   10

                                                  ARTICLE 4
                                       CERTAIN COVENANTS AND AGREEMENTS

Section 4.01.  Information.....................................................................   10
Section 4.02.  Reports.........................................................................   11
Section 4.03.  Cooperation in Refinancing......................................................   12
Section 4.04.  Appointment of Stockholder Representative.......................................   12

                                                  ARTICLE 5
                                                MISCELLANEOUS

Section 5.01.  Entire Agreement................................................................   12
Section 5.02.  Binding Effect; Benefit.........................................................   12
Section 5.03.  Assignability...................................................................   13
Section 5.04.  Waiver; Amendment; Termination..................................................   13
Section 5.05.  Notices.........................................................................   13
Section 5.06.  Fees and Expenses...............................................................   14
Section 5.07.  Headings........................................................................   14
Section 5.08.  Counterparts....................................................................   14
Section 5.09.  Applicable Law..................................................................   15
</TABLE>

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<PAGE>

<TABLE>
<S>                                                                                               <C>
Section 5.10.  Waiver of Jury Trial............................................................   15
Section 5.11.  Specific Enforcement............................................................   15
Section 5.12.  Consent to Jurisdiction.........................................................   15
Section 5.13.  Severability....................................................................   15
Section 5.14.  Recapitalization................................................................   16
Section 5.15.  No Inconsistent Agreements......................................................   16
</TABLE>

                                       ii
<PAGE>
                            STOCKHOLDERS' AGREEMENT

         AGREEMENT dated as of _____________, 2004 (the "AGREEMENT") among Ultra
Clean Holdings, Inc., a Delaware corporation (the "COMPANY"), FP-Ultra Clean,
LLC, a Delaware limited liability company ("FP"), and such additional persons as
may sign joinder agreements to this Agreement.

                              W I T N E S S E T H :

         WHEREAS, FP is currently the owner of a majority of the Common Stock of
the Company;

         WHEREAS, the parties hereto desire to enter into this Agreement to
govern certain of their rights, duties and obligations;

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

                                    ARTICLE 1
                                   DEFINITIONS

         Section 1.01. Definitions. (a) The following terms, as used herein,
have the following meanings:

         "AFFILIATE" means, with respect to any Person, any other Person
directly or indirectly controlling, controlled by or under common control with
such Person, provided that no securityholder of the Company shall be deemed an
Affiliate of any other securityholder solely by reason of any investment in the
Company. For the purpose of this definition, the term "CONTROL" (including with
correlative meanings, the terms "CONTROLLING," "CONTROLLED BY" and "UNDER COMMON
CONTROL WITH"), as used with respect to any Person, shall mean the possession,
directly or indirectly, of the power to direct or cause the direction of the
management and policies of such Person, whether through the ownership of voting
securities, by contract or otherwise.

         "AGGREGATE OWNERSHIP" means, with respect to any Stockholder or group
of Stockholders, and with respect to any class of Company Securities, the total
amount of such class of Company Securities "BENEFICIALLY OWNED" (as such term is
defined in Rule 13d-3 of the Exchange Act) (without duplication) by such
Stockholder or group of Stockholders as of the date of such calculation,
calculated on a Fully Diluted basis.

         "AGGREGATE OWNERSHIP PERCENTAGE" means, with respect to any Stockholder
(or group of Stockholders), and with respect to any class of Company

<PAGE>

Securities, the percentage equal to such Stockholder's (or group of
Stockholders') Aggregate Ownership of such class of Company Securities divided
by all outstanding Common Shares, calculated on a Fully Diluted basis.

         "BOARD" means the board of directors of the Company.

         "BUSINESS DAY" means any day except a Saturday, Sunday or other day on
which commercial banks in San Francisco or New York City are authorized by law
to close.

         "BYLAWS" means the bylaws of the Company, as amended from time to time.

         "CHARTER" means the certificate of incorporation of the Company, as the
same may be amended from time to time.

         "CODE" means the Internal Revenue Code of 1986, as amended from time to
time.

         "COMMON STOCK" means the Common Stock, par value $0.001 per share, of
the Company. "COMMON SHARES" means shares of Common Stock.

         "COMPANY SECURITIES" means (i) the Common Stock, (ii) securities
convertible into or exchangeable for Common Stock, and (iii) options, warrants
or other rights to acquire Common Stock or any other equity or equity-linked
security issued by the Company.

         "EXCHANGE ACT" means the Securities Exchange Act of 1934, as amended.

         "FIVE PERCENT STOCKHOLDER" means a Stockholder whose Aggregate
Ownership Percentage is 5% or more.

         "FOREIGN SUBSIDIARY" means, with respect to the Company, any entity
organized under the laws of a jurisdiction other than a State of the United
States of America of which securities or other ownership interests having
ordinary voting power to elect a majority of the board of directors or other
persons performing similar functions are at the time directly or indirectly
owned by the Company.

         "FULLY DILUTED" means, with respect to any class of Company Securities,
all outstanding shares and all shares issuable in respect of securities
convertible into or exchangeable for such shares, all stock appreciation rights,
options, warrants and other rights to purchase or subscribe for such Company
Securities or securities convertible into or exchangeable for such Company
Securities; provided that if any of the foregoing stock appreciation rights,
options, warrants or other rights to purchase or subscribe for such Company
Securities are subject

                                       2
<PAGE>

to vesting, the Company Securities subject to vesting shall be included in the
definition of "FULLY DILUTED" only upon and to the extent of such vesting.

         "INSIGNIFICANT SUBSIDIARY" means a subsidiary of the Company that does
not meet any of the conditions contained in the definition of "significant
subsidiary" as defined in Rule 1-02(w) of Regulation S-X promulgated under the
Securities Act.

         "INVESTMENT" means, with respect to any Person, (i) any direct or
indirect purchase or other acquisition by such Person of any notes, obligations,
instruments, stock, securities or ownership interest (including any partnership,
limited liability and joint venture interest) of any other Person and (ii) any
capital contribution by such Person to any other Person.

         "PERMITTED TRANSFEREE" means any Person so designated by FP in its sole
discretion.

         "PERSON" means an individual, corporation, limited liability company,
partnership, association, trust or other entity or organization, including a
government or political subdivision or an agency or instrumentality thereof.

         "REGISTRATION RIGHTS AGREEMENT" means the Registration Rights Agreement
dated as of December 2, 2002 between the Company and FP.

         "SEC" means the Securities and Exchange Commission.

         "SECURITIES ACT" means the Securities Act of 1933, as amended.

         "STOCKHOLDER" means at any time, any Person (other than the Company)
who shall then be a party to or bound by this Agreement, so long as such Person
shall "beneficially own" (as such term is defined in Rule 13d-3 of the Exchange
Act) any Company Securities.

         "SUBSIDIARY" means, with respect to any Person, any entity of which
securities or other ownership interests having ordinary voting power to elect a
majority of the board of directors or other persons performing similar functions
are at the time directly or indirectly owned by such Person.

         "THIRD PARTY" means a prospective purchaser(s) (other than a Permitted
Transferee or other Affiliate of such Stockholder) of Company Securities in an
arm's-length transaction from a Stockholder.

         "TRANSFER" means, with respect to any Company Security, (i) when used
as a verb, to sell, assign, dispose of, exchange, pledge, encumber, hypothecate
or otherwise transfer such security or any participation or interest therein,
whether directly or indirectly, or agree or commit to do any of the foregoing
and (ii) when

                                       3
<PAGE>

used as a noun, a direct or indirect sale, assignment, disposition, exchange,
pledge, encumbrance, hypothecation or other transfer of such security or any
participation or interest therein or any agreement or commitment to do any of
the foregoing.

         (b)      The term "FP," to the extent FP shall have transferred any of
its Company Securities, shall mean FP and such transferee or transferees, taken
together.

         (c)      Each of the following terms is defined in the Section set
forth opposite such term:

<TABLE>
<CAPTION>
          Term                                      Section
          ----                                      -------
<S>                                                 <C>
Additional Directors                                2.01
Agreement                                           Preamble
Cause                                               2.02
Company                                             Preamble
FP                                                  Preamble
FP Stockholder Representative                       4.04
Replacement Nominee                                 2.03(a)
Stockholder                                         5.03
</TABLE>

                                   ARTICLE 2
                              CORPORATE GOVERNANCE

         Section 2.01. Composition of the Board. (a) The Board shall consist of
nine directors, a majority of whom will be nominated by FP. One director will be
the Chief Executive Officer of the Company for so long as he or she is employed
by the Company. Three directors will be nominated by the Chief Executive Officer
and FP, provided that each such director (i) shall not be an "Affiliate" or an
"Associate" (as such terms are used within the meaning of Rule 12b-2 under the
Exchange Act) of FP and (ii) shall be an "independent director," as such term is
defined by the rules of the securities exchange or quotation system on which the
Common Stock is traded. If the number of directors that comprise the entire
Board is increased in accordance with Section 2.04 hereof, the number of
directors added to the Board (the "ADDITIONAL DIRECTORS") must be a multiple of
two, and FP shall continue to be entitled to nominate a majority of the Board as
provided in this Section 2.01.

         (b)      Each Stockholder entitled to vote for the election of
directors to the Board agrees that it will vote its Common Shares or execute a
proxy or written consent, as the case may be, and take all other necessary
action (including causing

                                       4
<PAGE>

the Company to call a special meeting of Stockholders) in order to ensure that
the composition of the Board is as set forth in this Section 2.01.

         (c)      The right of FP to nominate a majority of the members of the
Board pursuant to this Article 2 shall:

                  (i)      at such time as FP's Aggregate Ownership Percentage
         is less than 25%, be reduced to the right to nominate one-fourth of the
         members of the Board, rounded up to the nearest whole number of members
         of the Board if such fraction is not a whole number;

                  (ii)     at such time as FP's Aggregate Ownership Percentage
         is less than 20%, be reduced to the right to nominate one-fifth of the
         members of the Board, rounded up to the nearest whole number of members
         of the Board if such fraction is not a whole number;

                  (iii)    at such time as FP's Aggregate Ownership Percentage
         is less than 10%, be reduced to the right to nominate one-tenth of the
         members of the Board, rounded up to the nearest whole number of members
         of the Board if such fraction is not a whole number; and

                  (iv)     terminate at such time as FP's Aggregate Ownership
         Percentage is less than 5%.

         The obligations imposed on the Stockholders to give effect to the
rights to nominate directors set forth in this Section 2.01 shall terminate as
to any Person when such Person's right to nominate a director is terminated.

         (d)      The Company agrees to take all other necessary actions
(including calling a special meeting of the Board and/or Stockholders) to ensure
that the composition of the Board is as set forth in this Section 2.01.

         Section 2.02. Removal. Each Stockholder agrees that if at any time it
is then entitled to vote for the removal of directors from the Board, it will
not vote any of its Common Shares in favor of the removal of any director who
shall have been nominated in accordance with Section 2.01 hereof, unless such
removal shall be for Cause or the Person or Persons entitled to nominate such
director shall have consented to such removal in writing; provided that if the
Person or Persons entitled to nominate any director pursuant to Section 2.01
hereof shall request in writing the removal, with or without Cause, of such
director, such Stockholder shall vote its Common Shares in favor of such
removal. Removal for "CAUSE" shall mean removal of a director because of such
director's (a) willful and continued failure substantially to perform his or her
statutory or fiduciary duties to the Company in his or her established position,
(b) participation in a fraud, act of dishonesty or other misconduct that is
injurious, monetarily or otherwise, to the

                                       5
<PAGE>

Company or any of its Subsidiaries, (c) having been charged with or pleading
guilty to a felony or a crime involving fraud or dishonesty, (d) violation of
any state or federal law that has an adverse effect on the Company or (e) abuse
of illegal drugs or other controlled substances or habitual intoxication.

         Section 2.03. Vacancies. If, as a result of death, disability,
retirement, resignation, removal (with or without Cause) or otherwise, there
shall exist or occur any vacancy on the Board:

         (a)      the Person or Persons entitled under Section 2.01 hereof to
nominate such director whose death, disability, retirement, resignation or
removal resulted in such vacancy may, subject to the provisions of Section 2.01
hereof, nominate another individual (the "REPLACEMENT NOMINEE") to fill such
vacancy and serve as a director on the Board; and

         (b)      subject to Section 2.01 hereof, each Stockholder then entitled
to vote for the election of the Replacement Nominee as a director of the Company
agrees that it will vote its Common Shares, or execute a proxy or written
consent, as the case may be, in order to ensure that the Replacement Nominee be
elected to the Board.

         Section 2.04. Action by the Board. (a) A quorum of the Board shall
consist of a majority of the total number of directors, which such majority
shall include a majority of the nominees of FP; provided that if FP has not
nominated its independent directors pursuant to Section 2.01(a), such majority
will include all directors nominated by FP.

         (b)      All actions of the Board shall require (i) the affirmative
vote of at least a majority of the directors present at a duly convened meeting
of the Board at which a quorum is present or (ii) the unanimous written consent
of the Board; provided that if there is a vacancy on the Board and an individual
has been nominated to fill such vacancy, the first order of business shall be to
fill such vacancy.

         (c)      The Board may create executive, compensation, audit,
nominating and corporate governance and such other committees as it may
determine. During such time as FP's Aggregate Ownership Percentage is greater
than or equal to 25%, FP shall be entitled to majority representation on any
committee created by the Board, which majority representation shall consist of
any director or directors designated by FP to serve on such committee; provided
that if the rules or regulations of the SEC or the securities exchange or
quotation system on which the Common Stock is traded require any committee to
consist of one or more "independent directors," as such term is defined by the
rules of the securities exchange or quotation system on which the Common Stock
is traded, the directors designated to serve on such committee by FP shall be
"independent directors."

                                       6
<PAGE>

FP's entitlement to majority representation on any committee created by the
Board shall:

                  (i)      at such time as FP's Aggregate Ownership Percentage
         is less than 25%, be reduced to an entitlement to designate one-fourth
         of the members of each such committee, rounded up to the nearest whole
         number of members if such fraction is not a whole number;

                  (ii)     at such time as FP's Aggregate Ownership Percentage
         is less than 20%, be reduced to an entitlement to designate one-fifth
         of the members of each such committee, rounded up to the nearest whole
         number of members if such fraction is not a whole number;

                  (iii)    at such time as FP's Aggregate Ownership Percentage
         is less than 10%, be reduced to an entitlement to designate one-tenth
         of the members of each such committee, rounded up to the nearest whole
         number of members if such fraction is not a whole number; and

                  (iv)     terminate at such time as FP's Aggregate Ownership
         Percentage is less than 5%.

         (d)      At such time as FP's Aggregate Ownership Percentage is greater
than or equal to 25%, no action by the Company (including but not limited to any
action by the Board or any committee thereof) shall be taken with respect to any
of the following matters without the prior written consent of FP and the
affirmative approval of the Board:

                  (i)      the declaration of any dividend on or the making of
         any distribution with respect to, or the recapitalization,
         reclassification, redemption, repurchase or other acquisition of, any
         securities of the Company or any Subsidiary, except as expressly
         permitted by this Agreement;

                  (ii)     any incurrence, refinancing, alteration of material
         terms or prepayment by the Company or any Subsidiary of indebtedness
         for borrowed money in excess of $10,000,000 in the aggregate (or the
         guaranty by the Company or any Subsidiary of any such indebtedness);

                  (iii)    any approval of the annual business plan, budget and
         long-term strategic plan of the Company or any Subsidiary;

                  (iv)     any modification of the long-term business strategy
         or scope of the business of the Company or any Subsidiary or any
         material customer relationships thereof;

                                       7
<PAGE>

                  (v)      (A) any merger or consolidation of the Company with
         or into any Person, other than a wholly owned Subsidiary, or of any
         Subsidiary with or into any Person other than the Company or any other
         wholly owned Subsidiary, or (B) any sale of the Company or any
         Subsidiary or any significant operations of the Company or any
         Subsidiary or any joint venture transaction, acquisition or disposition
         of assets, business, operations or securities by the Company or any
         Subsidiary (in a single transaction or a series of related
         transactions) having a value in each case in this clause (B) in excess
         of $10,000,000;

                  (vi)     any liquidation, dissolution, commencement of
         bankruptcy, liquidation or similar proceedings with respect to the
         Company or any Subsidiary;

                  (vii)    the issuance of any security by the Company or any
         Subsidiary (not including issuances of such securities in connection
         with employee or stock option plans previously approved by the Board),
         other than as specifically contemplated by this Agreement;

                  (viii)   any determination of compensation, benefits,
         perquisites and other incentives for the Chief Executive Officer or the
         Chief Financial Officer of the Company or its Subsidiaries and the
         approval or amendment of any plans or contracts in connection
         therewith, and any approval or amendment to any equity or other
         compensation or benefit plans for employees of the Company or its
         Subsidiaries;

                  (ix)     any appointment or dismissal of any of the Chairman
         of the Board, Chief Executive Officer, Chief Financial Officer or any
         other executive officer in any similar capacity of the Company or any
         Subsidiary;

                  (x)      any amendment to this Agreement, any exercise or
         waiver of the Company's rights under this Agreement, any amendment to
         the Charter or Bylaws or any adoption of or amendment to the
         certificate of incorporation or bylaws of any Subsidiary; or

                  (xi)     any increase or decrease to the number of Directors
         that comprise the entire Board of the Company or any Subsidiary.

         Section 2.05 . Conflicting Charter or Bylaw Provisions. Each
Stockholder shall vote its Common Shares or execute proxies or written consents,
as the case may be, and shall take all other actions necessary to ensure that
the Company's Charter and Bylaws (i) facilitate, and do not at any time conflict
with, any provision of this Agreement and (ii) permit each Stockholder to
receive the benefits to which each such Stockholder is entitled under this
Agreement.

                                       8
<PAGE>

         Section 2.06. Subsidiary Governance. The Company and each Stockholder
agree that (i) the board of directors or other persons performing similar
functions of each Subsidiary of the Company (other than any Foreign Subsidiary
and any Insignificant Subsidiary) shall be comprised of the individuals who are
serving as directors on the Board in accordance with Section 2.01 hereof and
(ii) the board of directors or other persons performing similar functions of any
Subsidiary of the Company shall be subject to all the provisions of this Article
2, including paragraph Section 2.04(d) of Section 2.04 hereof. Each Stockholder
agrees to vote its Common Shares and to cause its representatives on the Board,
subject to their fiduciary duties, to vote and take other appropriate action to
effectuate the agreements in this Section 2.06 in respect of any Subsidiary of
the Company.

                                   ARTICLE 3
                            RESTRICTIONS ON TRANSFER

         Section 3.01. General. (a) Each Stockholder understands and agrees that
the Company Securities acquired prior to the date of this Agreement have not
been registered under the Securities Act and are restricted securities under
such Act and the rules and regulations promulgated thereunder. Each Stockholder
agrees that it will not Transfer any Company Securities (or solicit any offers
in respect of any Transfer of any Company Securities), except in compliance with
the Securities Act, any applicable foreign or state securities or "blue sky"
laws, and the terms and conditions of this Agreement.

         (b)      Any attempt to Transfer any Company Securities not in
compliance with this Agreement shall be null and void and the Company shall not,
and shall cause any transfer agent not to, give any effect in the Company's
stock records to such attempted Transfer.

         Section 3.02. Legends. (a) In addition to any other legend that may be
required, each certificate for Company Securities that is issued to any
Stockholder shall bear a legend in substantially the following form:

         "THIS SECURITY HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF
1933, AS AMENDED, OR ANY FOREIGN OR STATE SECURITIES LAWS AND MAY NOT BE OFFERED
OR SOLD EXCEPT IN COMPLIANCE THEREWITH. THIS SECURITY IS ALSO SUBJECT TO
ADDITIONAL RESTRICTIONS ON TRANSFER AS SET FORTH IN THE STOCKHOLDERS' AGREEMENT
DATED AS OF _______________, 2004, COPIES OF WHICH MAY BE OBTAINED UPON REQUEST
FROM ULTRA CLEAN HOLDINGS, INC. OR ANY SUCCESSOR THERETO."

                                       9
<PAGE>

         (b)      If any Company Securities shall cease to be Registrable
Securities (as defined in the Registration Rights Agreement) under clause (i) or
clause (ii) of the definition thereof, the Company, upon the written request of
the holder thereof, shall issue to such holder a new certificate evidencing such
shares without the first sentence of the legend required by Section 3.02(a)
hereof endorsed thereon. If any Company Securities cease to be subject to any
and all restrictions on Transfer set forth in this Agreement, the Company, upon
the written request of the holder thereof, shall issue to such holder a new
certificate evidencing such Company Securities without the second sentence of
the legend required by Section 3.02(a) hereof endorsed thereon.

         Section 3.03. Restrictions on Transfer. Except with the prior written
consent of the Company and FP, no Stockholder shall Transfer any of its Company
Securities.

         Section 3.04. Permitted Transferees. Notwithstanding anything in this
Agreement to the contrary, FP may at any time Transfer any or all of its Company
Securities to one or more Permitted Transferees without the consent of the
Company or any other Stockholder or group of Stockholders; provided that (a)
such Permitted Transferee shall, if so required by FP, agree in writing to be
bound by the terms of this Agreement in the form of Exhibit A attached hereto,
and (b) the Transfer to such Permitted Transferee is in compliance with the
Securities Act and any other applicable securities or "blue sky" laws.

                                   ARTICLE 4
                        CERTAIN COVENANTS AND AGREEMENTS

         Section 4.01. Information. The Company agrees to furnish FP, for so
long as FP owns any Company Securities:

         (a)      as soon as practicable and in any event no later than 20 days
after the end of each fiscal month, a management report for such month covering
the items set forth in Exhibit B hereto;

         (b)      as soon as practicable and, in any event, within 45 days after
the end of each of the first three fiscal quarters, the unaudited consolidated
balance sheet of the Company and its Subsidiaries as at the end of such quarter
and the related unaudited statement of operations and cash flow for such quarter
and for the portion of the fiscal year then ended, in each case prepared in
accordance with GAAP;

         (c)      as soon as practicable and, in any event, within 90 days after
the end of each fiscal year, (i) the audited consolidated balance sheet of the
Company and its Subsidiaries as at the end of such fiscal year and the related
audited statement

                                       10
<PAGE>

of operations and cash flow for such fiscal year, and for the portion of the
fiscal year then ended, in each case prepared in accordance with GAAP and
certified by Deloitte & Touche or another firm of independent public accountants
of nationally recognized standing, together with a comparison of the figures in
such financial statements with the figures for the previous fiscal year and the
figures in the Company's annual operating budget, (ii) any management letters or
other correspondence from such accountants and (iii) the Company's annual
operating budget for the coming fiscal year,

         (d)      promptly following the preparation thereof, a copy of any
revisions to the annual operating budget delivered pursuant to clause (c) above,

         (e)      promptly upon their becoming available, copies of (i) all
financial statements, reports, notices and proxy statements sent or made
generally available by the Company to any of its security holders, (ii) all
regular and periodic reports and all registration statements and prospectuses
filed by the Company with any securities exchange or with the SEC and (iii) all
press releases and other statements made generally available by the Company to
the public,

         (f)      as soon as practicable and, in any event, within five Business
Days after any officer of the Company obtains knowledge thereof, notice (with a
description in reasonable detail, and stating the action that the Company is
taking or proposes to take with respect thereto) of (i) the commencement of any
material litigation, investigation or other proceeding to which the Company or
any of its Subsidiaries is a party before any court or arbitrator or any
governmental body, agency or official or (ii) the existence of any material
default or breach under this Agreement or any other material contract or
agreement to which the Company or any of its Subsidiaries is a party, and

         (g)      as promptly as reasonably practicable, such other information
with respect to the Company or any of its Subsidiaries as may reasonably be
requested by FP.

         The Company's obligation to provide information pursuant to Section
4.01(a) and (b) and Section 4.02 shall be deemed satisfied upon the timely
filing of such information with the SEC.

         Section 4.02. Reports. The Company will furnish the Stockholders with
the quarterly and annual financial reports that the Company is required to file
with the SEC pursuant to Section 13 or Section 15(d) of the Exchange Act or, in
the event the Company is not required to file such reports, quarterly and annual
reports containing the same information as would otherwise be required in such
reports. The Company's obligation to provide information pursuant to this
Section 4.01 shall be deemed satisfied upon the timely filing of such
information with the SEC.

                                       11
<PAGE>

         Section 4.03. Cooperation in Refinancing. Each Stockholder agrees to
cooperate to the extent commercially reasonable with the Company and take such
steps as the Board reasonably deems appropriate in any financing of debt of the
Company and any of its Subsidiaries, including executing such documents as the
Board reasonably determines should be filed with any governmental agency and
conducting presentations to potential investors and rating agencies. This
Section 4.03 shall not be construed to require any Stockholder to contribute any
additional capital to the Company.

         Section 4.04. Appointment of Stockholder Representative. FP and its
Permitted Transferees, if any, irrevocably appoint the FP Stockholder
Representative its agent and true and lawful attorney-in-fact, with full power
of substitution, to take the actions, receive notices and exercise the powers
delegated to the FP Stockholder Representative under this Agreement in the name
of each such Stockholder, together with such actions and powers as are
reasonably incidental thereto. Notwithstanding the foregoing, the FP Stockholder
Representative shall not take any action or exercise any power to the extent
that the holders of the majority of the Fully Diluted Common Shares held by FP
and its Permitted Transferees shall have voted to prevent the Stockholder
Representative from taking such action or exercising such power. "FP STOCKHOLDER
REPRESENTATIVE" means FP, as agent for FP and its Permitted Transferees. The
entity appointed as the FP Stockholder Representative may be replaced at any
time and from time to time by the vote of a majority of the Fully Diluted Common
Shares held by FP and its Permitted Transferees. FP shall notify the Company of
such appointment as promptly as practicable after such appointment.

                                    ARTICLE 5
                                  MISCELLANEOUS

         Section 5.01. Entire Agreement. This Agreement, the Registration Rights
Agreement, the Charter and the Bylaws constitute the entire agreement among the
parties hereto and supersede all prior and contemporaneous agreements and
understandings, both oral and written, among the parties hereto with respect to
the subject matter hereof and thereof.

         Section 5.02. Binding Effect; Benefit. This Agreement shall inure to
the benefit of and be binding upon the parties hereto and their respective
heirs, successors, legal representatives and permitted assigns. Nothing in this
Agreement, expressed or implied, is intended to confer on any Person other than
the parties hereto, and their respective heirs, successors, legal
representatives and permitted assigns, any rights, remedies, obligations or
liabilities under or by reason of this Agreement.

                                       12
<PAGE>

         Section 5.03. Assignability. Neither this Agreement nor any right,
remedy, obligation or liability arising hereunder or by reason hereof shall be
assignable by any party hereto pursuant to any Transfer of Company Securities or
otherwise, except that, subject to Section 3.04 hereof, any Permitted Transferee
acquiring Company Securities and any Person acquiring Company Securities who is
required by the terms of this Agreement or any employment agreement or stock
purchase, option, stock option or other compensation plan of the Company or any
Subsidiary to become a party hereto shall (unless already bound hereby) execute
and deliver to the Company an agreement to be bound by this Agreement in the
form of Exhibit A hereto and shall thenceforth be a "STOCKHOLDER." Any
Stockholder who ceases to own beneficially any Company Securities shall cease to
be bound by the terms hereof (other than Sections 5.09, 5.10, 5.11 and 5.12).

         Section 5.04. Waiver; Amendment; Termination. (a) No provision of this
Agreement may be waived except by an instrument in writing executed by the party
against whom the waiver is to be effective. No provision of this Agreement may
be amended or otherwise modified except by an instrument in writing executed by
the Company with approval of the Board and Stockholders (including FP) holding
at least 50% of the outstanding Common Shares held by the parties hereto at the
time of such proposed amendment or modification.

         (b)      Any amendment or modification of any provision of this
Agreement that would adversely affect FP may be effected only with the consent
of FP.

         Section 5.05. Notices. All notices, requests and other communications
to any party shall be in writing (including facsimile transmissions) and shall
be given,

         if to the Company to:

                           Ultra Clean Holdings, Inc.
                           150 Independence Drive
                           Menlo Park, CA 94025
                           Attention: Chief Executive Officer
                           Fax: (650) 326-0929

         with a copy to FP at the address listed below.

                                       13
<PAGE>

         if to FP, to:

                           FP-Ultra Clean, LLC
                           c/o Francisco Partners, L.P.
                           2882 Sand Hill Road, Suite 280
                           Menlo Park, CA 94025
                           Attention: Dipanjan Deb
                           Fax: (650) 233-2999

         with a copy to:

                           Davis Polk & Wardwell
                           1600 El Camino Real
                           Menlo Park, CA 94025
                           Attention: Alan F. Denenberg, Esq.
                           Fax: (650) 752-2111

         All notices, requests and other communications shall be deemed received
on the date of receipt by the recipient thereof if received prior to 5:00 p.m.
in the place of receipt and such day is a Business Day in the place of receipt.
Otherwise, any such notice, request or communication shall be deemed not to have
been received until the next succeeding Business Day in the place of receipt.
Any notice, request or other written communication sent by facsimile
transmission shall be confirmed by certified mail, return receipt requested,
posted within one Business Day, or by personal delivery, whether courier or
otherwise, made within two Business Days after the date of such facsimile
transmissions.

         Any Person who becomes a Stockholder shall provide its address and fax
number to the Company, which shall promptly provide such information to each
other Stockholder.

         Section 5.06. Fees and Expenses. The Company shall pay all
out-of-pocket costs and expenses of the Stockholders, including the fees and
expenses of counsel, incurred in connection with the preparation of this
Agreement, or any amendment or waiver hereof, and the transactions contemplated
hereby and all matters related hereto.

         Section 5.07. Headings. The headings contained in this Agreement are
for convenience only and shall not affect the meaning or interpretation of this
Agreement.

         Section 5.08. Counterparts. This Agreement may be executed in any
number of counterparts, each of which shall be deemed to be an original and all
of which together shall be deemed to be one and the same instrument.

                                       14
<PAGE>

         Section 5.09. Applicable Law. This Agreement shall be governed by, and
construed in accordance with, the laws of the State of Delaware, without regard
to the conflicts of laws rules of such state.

         Section 5.10. Waiver of Jury Trial. EACH OF THE PARTIES HERETO HEREBY
IRREVOCABLY WAIVES ANY AND ALL RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING
ARISING OUT OF OR RELATED TO THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED
HEREBY.

         Section 5.11. Specific Enforcement. Each party hereto acknowledges that
the remedies at law of the other parties for a breach or threatened breach of
this Agreement would be inadequate and, in recognition of this fact, any party
to this Agreement, without posting any bond, and in addition to all other
remedies that may be available, shall be entitled to obtain equitable relief in
the form of specific performance, a temporary restraining order, a temporary or
permanent injunction or any other equitable remedy that may then be available.

         Section 5.12. Consent to Jurisdiction. The parties hereby agree that
any suit, action or proceeding seeking to enforce any provision of, or based on
any matter arising out of or in connection with, this Agreement or the
transactions contemplated hereby shall be brought in the United States District
Court for the District of Delaware or any Delaware State court sitting in
Delaware, so long as one of such courts shall have subject matter jurisdiction
over such suit, action or proceeding, and that any cause of action arising out
of this Agreement shall be deemed to have arisen from a transaction of business
in the State of Delaware, and each of the parties hereby irrevocably consents to
the nonexclusive jurisdiction of such courts (and of the appropriate appellate
courts therefrom) in any such suit, action or proceeding and irrevocably waives,
to the fullest extent permitted by law, any objection that it may now or
hereafter have to the laying of the venue of any such suit, action or proceeding
in any such court or that any such suit, action or proceeding which is brought
in any such court has been brought in an inconvenient form. Process in any such
suit, action or proceeding may be served on any party anywhere in the world,
whether within or without the jurisdiction of any such court. Without limiting
the foregoing, each party agrees that service of process on such party as
provided in Section 5.05 shall be deemed effective service of process on such
party.

         Section 5.13. Severability. If one or more provisions of this Agreement
are held to be unenforceable to any extent under applicable law, such provision
shall be interpreted as if it were written so as to be enforceable to the
maximum possible extent so as to effectuate the parties' intent to the maximum
possible extent, and the balance of the Agreement shall be interpreted as if
such provision were so excluded and shall be enforceable in accordance with its
terms to the maximum extent permitted by law.

                                       15
<PAGE>

         Section 5.14. Recapitalization. If any capital stock or other
securities are issued in respect of, in exchange for, or in substitution of, any
Company Securities by reason of any reorganization, recapitalization,
reclassification, merger, consolidation, spin-off, partial or complete
liquidation, stock dividend, split-up, sale of assets, distribution to
stockholders or combination of the Company Securities or any other change in
capital structure of the Company, appropriate adjustments shall be made with
respect to the relevant provisions of this Agreement so as fairly and equitably
to preserve, as far as practicable, the original rights and obligations of the
parties hereto under this Agreement.

         Section 5.15. No Inconsistent Agreements. The Company will not
hereafter enter into any agreement with respect to its securities that is
inconsistent with, or grants rights superior to the rights granted to the
Stockholders pursuant to, this Agreement. The Company represents and warrants to
each Stockholder that it has not previously entered into any agreement with
respect to any of its securities granting any registration rights to any Person.

                                       16
<PAGE>

         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed by their respective authorized officers as of the day and year
first above written.

ULTRA CLEAN HOLDINGS, INC.

By:__________________________
     Name:
     Title:

FP-ULTRA CLEAN, LLC

     By: FRANCISCO PARTNERS, L.P.,
         Managing Member
By:___________________________
   Name: Dipanjan Deb
   Title: Partner

<PAGE>

                                                                       EXHIBIT A

                       JOINDER TO STOCKHOLDERS' AGREEMENT

         This Joinder Agreement (this "JOINDER AGREEMENT") is made as of the
date written below by the undersigned (the "JOINING PARTY") in accordance with
the Stockholders' Agreement dated as of _______________, 2004 (the
"STOCKHOLDERS' AGREEMENT") between Ultra Clean Holdings, Inc. and FP-Ultra
Clean, LLC, as the same may be amended from time to time. Capitalized terms
used, but not defined, herein shall have the meaning ascribed to such terms in
the Stockholders' Agreement.

         The Joining Party hereby acknowledges, agrees and confirms that, by its
execution of this Joinder Agreement, the Joining Party shall be deemed to be a
party to the Stockholders' Agreement as of the date hereof and shall have all of
the rights and obligations of a "Stockholder" thereunder as if it had executed
the Stockholders' Agreement. The Joining Party hereby ratifies, as of the date
hereof, and agrees to be bound by, all of the terms, provisions and conditions
contained in the Stockholders' Agreement.

         The Joining Party's Aggregate Ownership is __________ Common Shares as
of the date written below.

         IN WITNESS WHEREOF, the undersigned has executed this Joinder Agreement
as of the date written below.

Date: ___________ ___, 20___

                                                  [NAME OF JOINING PARTY]

                                                  By: __________________________
                                                      Name:
                                                      Title:

                                                      Address for Notices:

<PAGE>

                                                                       EXHIBIT B

                     MATTERS TO BE INCLUDED IN THE COMPANY'S
                            MONTHLY MANAGEMENT REPORT

1.    The unaudited consolidated balance sheet of the Company and its
      Subsidiaries as at the end of such month and the related unaudited
      statement of operations and cash flow for such month, and for the portion
      of the fiscal year then ended, in each case prepared in accordance with
      GAAP, setting forth in comparative form the figures for the corresponding
      month and portion of the previous fiscal year, and the figures for the
      corresponding month and portion of the then current fiscal year as in the
      Company's annual operating budget.

2.    Projected monthly income statements prepared on the same basis as those
      specified in Item 1, including revenue forecasts by customer and expense
      budget by major expense category, for periods extending through a minimum
      of one year from the date of the report.

3.    A summary of realized and projected sales bookings for the most recent
      month and for periods extending through a minimum of one year from the
      date of the report, including probability-weighted "pipeline" projections
      of new bookings to the extent that the Company compiles such data for
      internal purposes.