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                                                                    EXHIBIT 10.6

                      FOURTH AMENDMENT TO CREDIT AGREEMENT

                This Amendment, dated as of February 26, 2003, is made by and
among ENTEGRIS, INC., a Minnesota corporation (the "Borrower"), each of the
banks appearing on the signature pages hereof, together with such other banks as
may from time to time become a party to the Credit Agreement (defined below)
pursuant to the terms and conditions of Article VIII of the Credit Agreement
(herein collectively called the "Banks" and individually each called a "Bank"),
and WELLS FARGO BANK, NATIONAL ASSOCIATION, a national banking association,
assignee of Wells Fargo Bank Minnesota, National Association, formerly known as
Norwest Bank Minnesota, National Association, in its separate capacity as
administrative agent for itself and all other Banks (in such capacity, the
"Agent").

                                    Recitals

                A.      The Borrower, the Banks and the Agent have entered into
a Credit Agreement dated as of November 30, 1999, as amended by a First
Amendment to Credit Agreement dated as of October 17, 2000, a Second Amendment
to Credit Agreement dated as of March 1, 2002 and a Consent and Amendment
Agreement dated as of February 7, 2003 (as so amended, the "Credit Agreement").

                B.      The Borrower has requested that the Banks and the Agent,
among other things (i) increase the Revolving Commitment Amount, (ii) extend the
maturity of the credit facility provided under the Credit Agreement, and (iii)
amend certain other provisions of the Credit Agreement.

                C.      The Banks and the Agent are willing to grant the
Borrower's requests subject to the terms and conditions set forth below.

                ACCORDINGLY, in consideration of the premises and for other good
and valuable consideration, the Borrower, the Banks and the Agent agree as
follows:

                1.      All capitalized terms used in this Amendment and not
otherwise specifically defined in this Amendment shall have the meanings given
such terms in the Credit Agreement.

                2.      Section 1.1 of the Credit Agreement is hereby amended by
amending or adding, as applicable, the following definitions to read in their
entirety as follows:

                '"Acquisition' means the acquisition by the Borrower and
        Entegris Cayman of certain assets of Asyst pursuant to the Acquisition
        Documents."

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                '"Acquisition Documents' means (a) the Asset Purchase Agreement
        dated as of February 11, 2003 among Asyst, the Borrower and Entegris
        Cayman, (b) the Patent Assignment and Cross-License and Trademark
        License Agreement dated as of February 11, 2003 between Asyst and the
        Borrower, (c) the Transition Services Agreement dated as of February 11,
        2003 among Asyst, the Borrower and Entegris Cayman, (d) the Escrow
        Agreement dated as of February 11, 2003 among Asyst, the Borrower,
        Entegris Cayman and Wells Fargo Bank, National Association in its
        capacity as escrow agent thereunder, and (e) separate Employment
        Agreements of John Burns and Gary Gallagher dated as of February 11,
        2003, including, in each case, all exhibits, schedules and other
        attachments thereto."

                '"Asyst' means Asyst Technologies, Inc., a California
        corporation."

                '"Base Rate' means the Prime Rate."

                '"Capital Expenditure' means any expenditure of money for the
        purchase or construction of fixed assets or for the purchase or
        construction of any other assets, or for improvements or additions
        thereto, which are capitalized on the Borrower's balance sheet, whether
        payable currently or in the future, excluding, however, any expenditure
        of cash in connection with an acquisition of stock or assets of another
        Person permitted under Section 6.4 of this Agreement."

                '"Cash Taxes' means, with respect to the applicable Covenant
        Computation Period, the Tax Expense for such Covenant Computation
        Period, plus (minus) any increase (decrease) in deferred tax assets
        during such Covenant Computation Period and minus (plus) any increase
        (decrease) in deferred tax liabilities during such Covenant Computation
        Period."

                '"Consent' means the Consent and Amendment Agreement dated as of
        February 7, 2003 among the Borrower, the Agent and the Banks."

                '"Domestic Cash' means the cash and cash equivalents owned by
        the Borrower and/or the Borrower's Domestic Subsidiaries."

                '"Domestic Subsidiary' means a Subsidiary organized under the
        laws of one of the States of the United States."

                '"Domestic Tangible Net Worth' means the sum (without
        duplication) of the Tangible Net Worth of (i) the Borrower, (ii) the
        Borrower's Domestic Subsidiaries, and (iii) the Guarantors, determined
        on a consolidated basis in accordance with GAAP; provided, however,
        that, for purposes of calculating Domestic Tangible Net Worth (a)
        Domestic Tangible Net Worth shall not include the Tangible Net Worth (or
        any portion thereof) of or attributable to a Foreign Subsidiary which is
        not also a Guarantor, (b) neither an investment of the Borrower, any
        Domestic Subsidiary or any

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        Guarantor in or to any Foreign Subsidiary nor any receivables due to the
        Borrower, any Domestic Subsidiary or any Guarantor from any Foreign
        Subsidiary shall be included in any determination of Domestic Tangible
        Net Worth, (c) the Tangible Net Worth of any Foreign Subsidiary which is
        also a Guarantor shall be limited to an amount agreed to by the Agent,
        the Banks and the Borrower upon such Foreign Subsidiary's becoming a
        Guarantor and, if not so agreed, such amount shall at all times be zero,
        and (d) the Specified Foreign Trade Receivables shall be included as
        tangible assets of the Borrower)."

                '"Entegris Cayman' means Entegris Cayman Ltd., a Cayman Island
        corporation and wholly-owned Subsidiary of the Borrower."

                '"Entegris Custom Products' means Entegris Custom Products,
        Inc., a Minnesota corporation."

                '"Financial Covenants' means the covenants contained in Sections
        5.8 through 5.13."

                "'Fixed Charge Coverage Ratio' means, with respect to the
        applicable Covenant Computation Period, the ratio of (a) EBITDA, plus
        Rent Expense, less Capital Expenditures, less Cash Taxes (whether or not
        included in the calculation of EBITDA), less Permitted Restricted
        Payments, to (b) Interest Expense, plus Rent Expense, plus current
        maturities of Long Term Debt."

                '"Foreign Subsidiary' means a Subsidiary other than a Domestic
        Subsidiary."

                '"Fourth Amendment' means the Fourth Amendment to Credit
        Agreement dated as of February 26, 2003 among the Borrower, the Banks
        and the Agent."

                '"Guarantor' means NT International, Entegris Custom Products
        and each other Subsidiary of the Borrower that executes and delivers a
        Guaranty in favor of the Agent and the Banks and (a) "Guarantors" means
        all of them, and (b) "either of the Guarantors" (or similarly
        constructed phrases) means "any of the Guarantors"."

                '"Guaranty' means a Guaranty of a Guarantor in favor of the
        Agent and the Banks, in form and substance satisfactory to the Agent,
        guaranteeing the Obligations, as the same may be amended, supplemented
        or restated from time to time, and "Guaranties" means all of them."

                '"Intercompany Loan' means a loan by the Borrower to one or more
        of its Subsidiaries or a loan by one or more of the Borrower's
        Subsidiaries to the Borrower."

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                '"Maturity Date' means February 27, 2004 with respect to the
        Revolving Facility."

                '"NT International' means NT International, Inc., a Minnesota
        corporation."

                '"Percentage' means, as to any Bank, the percentage set forth
        opposite such Bank's signature on the execution pages of the Fourth
        Amendment, or below such Bank's signature on any Assignment Certificate
        executed by such Bank, representing the ratio of such Bank's Revolving
        Commitment to the Revolving Commitment Amount."

                '"Prime Rate' means the rate of interest publicly announced from
        time to time by the Agent as its "prime" or "base" rate or, if the Agent
        ceases to announce a rate so designated, any similar successor rate
        designated by the Required Banks."

                '"Prior Guarantors' means Empak and Fluoroware."

                '"Prior Guarantor Obligations' means all obligations of Empak
        and/or Fluoroware to the Agent or the Banks under or in connection with
        the Credit Agreement, their respective Guaranties or the other Loan
        Documents as the same existed immediately prior to their merger with and
        into the Borrower, including, without limitation all obligations of
        Fluoroware with respect to the IDRB Financing, IDRB Letter of Credit and
        IDRB Letter of Credit Reimbursement Agreement."

                '"Required Net Worth Amount' [deleted]."

                "'Revolving Commitment' means, with respect to each Bank, the
        amount of the Revolving Commitment set forth opposite such Bank's name
        on the execution pages of the Fourth Amendment, or below such Bank's
        signature on an Assignment Certificate executed by such Bank, unless
        such amount is reduced pursuant to Section 2.14(a) hereof, in which
        event it means the amount to which said amount is reduced pursuant
        thereto, or as the context may require, the obligation of such Bank to
        make Revolving Advances, as contemplated in Section 2.1."

                "'Revolving Commitment Amount' shall mean Forty Million Dollars
        ($40,000,000), being the maximum amount of the Revolving Commitments of
        all Banks, in the aggregate, to make Revolving Advances to the Borrower
        pursuant to Section 2.1, subject to reduction in accordance with Section
        2.14(a)."

                "'Revolving Commitment Period' means a 364-day period commencing
        on February 28, 2003 and ending on the Maturity Date, unless the
        Revolving Commitments are earlier terminated pursuant to Section 7.2 or
        are earlier reduced to zero pursuant to Section 2.14(a)."

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                "'Revolving Note' means a promissory note of the Borrower
        payable to a Bank in the amount of such Bank's Revolving Commitment, in
        substantially the form of Exhibit A (as such promissory note may be
        amended, extended or otherwise modified from time to time), evidencing
        the aggregate indebtedness of the Borrower to such Bank resulting from
        such Bank's Percentage of each Borrowing under the Revolving Facility,
        and also means each promissory note accepted by such Bank from time to
        time in substitution therefor or in renewal thereof."

                '"Specified Affiliates' means OregonLabs LLC, a Minnesota
        limited liability company, Metron Technology, SV, a Netherlands
        corporation, Xiangfan Huaguang Atcor Technolgy, LLC, a Chinese limited
        liability company and Entegris Precision Technology, Ltd., a Taiwan
        corporation."

                '"Specified Receivables' means receivables due to the Borrower
        from a Specified Affiliate on and as of the date of the Fourth
        Amendment, but shall in no event include any receivable generated or due
        on or after the date of the Fourth Amendment."

                '"Specified Investments' means investments by the Borrower in a
        Specified Affiliate on and as of the date of the Fourth Amendment, but
        shall in no event include any investment of the Borrower in or to such
        Specified Affiliate made on or after the date of the Fourth Amendment."

                '"Specified Foreign Trade Receivables' means the aggregate
        amount of all trade receivables due to the Borrower from any one or more
        of its Foreign Subsidiaries."

                "'Tangible Net Worth' of a Person means, as of the applicable
        Covenant Computation Date, the difference between (a) the tangible
        assets of such Person, calculated in accordance with GAAP, after
        deducting adequate reserves in each case where, in accordance with GAAP,
        a reserve is proper and (b) all Debt of such Person; provided, that in
        no event shall there be included as tangible assets: patents,
        trademarks, tradenames, copyrights, licenses, goodwill, receivables due
        from or investments in Affiliates of such Person (but Specified
        Receivables and Specified Investments shall be included as tangible
        assets of the Borrower), prepaid expenses, deposits, deferred charges or
        treasury stock or any securities or Debt of such Person, or any other
        securities unless such securities are readily marketable on a public
        exchange in the United States of America or are entitled to be used as a
        credit against federal income tax liabilities, and any other assets
        designated from time to time by the Agent, in its reasonable discretion,
        as intangible assets."

                '"Tax Expense' means, with respect to any Person with respect
        to the applicable Covenant Computation Period, federal, state, local and
        foreign income tax expense recognized by such Person with respect to
        such Covenant Computation Period, as determined in accordance with
        GAAP."

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                "'Unused Commitment Fee Percentage' means, as of the date of
        determination, the percentage set forth in the table below opposite the
        applicable range of the ratio of Total Funded Debt to EBITDA of the
        Borrower and its Subsidiaries as of such date of determination;
        provided, however, notwithstanding the foregoing, the Unused Commitment
        Fee Percentage shall be 0.200% so long as the Borrower is in compliance
        with the requirements of Section 5.12 hereof. Reductions and increases
        in the Unused Commitment Fee Percentage will be verified by the Agent
        upon receipt of the financial statements of the Borrower and its
        Subsidiaries and related compliance certificate as required under
        Section 5.1(b) of this Agreement. The ratio will be determined on the
        basis of a rolling four quarter calculation of the ratio of Total Funded
        Debt to EBITDA as of the last day of the most recent quarter-end
        reflected in the most recent financial statements delivered by the
        Borrower for the Borrower and its Subsidiaries under Section 5.1(b). Any
        reduction or increase in the Unused Commitment Fee Percentage will
        become effective on the first day of the first month following the
        applicable Quarterly Financial Statement Due Date. If the Borrower fails
        to deliver the financial statements of the Borrower and its Subsidiaries
        and/or related compliance certificate required under Section 5.1(b) on
        or before the applicable Quarterly Financial Statement Due Date, the
        Borrower and its Subsidiaries shall be deemed to have a ratio of Total
        Funded Debt to EBITDA for such quarter of more than 2.00 to 1.00, and
        the Unused Commitment Fee Percentage will be 0.350% beginning on the
        first day of the first month following such Quarterly Financial
        Statement Due Date and will continue as such until the Borrower delivers
        the financial statements of the Borrower and its Subsidiaries for the
        next fiscal quarter in accordance with Section 5.1(b).

              Ratio of Total Funded                    Unused Commitment Fee
                 Debt to EBITDA                             Percentage
         -------------------------------------------------------------------
                   * 2.00/1.00                               0.350%
         -------------------------------------------------------------------
            * 1.50/1.00 to 2.00/1.00                         0.300%
         -------------------------------------------------------------------
            1.00/1.00 to 1.50/1.00                           0.250%
         -------------------------------------------------------------------
                  ** 1.00/1.00                               0.200%
         -------------------------------------------------------------------
* - less than
** - greater than

                3.      Addition of Section 1.2 to the Credit Agreement. Section
1.2 is hereby added to the Credit Agreement as follows:

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                "Section 1.2 References to Empak, Fluoroware and Related
        References. The parties hereto acknowledge and agree that both Empak and
        Fluoroware have been merged with and into the Borrower as contemplated
        by the Second Amendment and that all Prior Guarantor Obligations have
        been assumed by the Borrower as a result of such merger. As a
        consequence of the foregoing, all Prior Guarantor Obligations shall be
        deemed to be obligations of the Borrower and all references in the
        Credit Agreement or any other Loan Document to "Empak" or "Fluoroware"
        or related terms shall be construed consistently with this Section 1.2
        and shall not be given independent or additional effect."

                4.      Addition of Section 1.3 to the Credit Agreement. Section
1.3 is hereby added to the Credit Agreement as follows:

                "Section 1.2 References to Guarantors and Guaranties. Certain
        Subsidiaries of the Borrower have agreed to guarantee the obligations of
        the Borrower under and with respect to the Credit Agreement and the
        other Loan Documents. All references in the Credit Agreement or the
        other Loan Documents to "Guarantors", "Guaranties" or like defined terms
        shall be deemed to refer to the Guarantors and Guaranties as each such
        term is defined in the Credit Agreement as amended, modified or
        otherwise supplemented to date; provided, however, that the foregoing
        shall not limit the Borrower's responsibility for or assumption of the
        Prior Guarantor Obligations."

                5.      Amendment of Section 2.13 of the Credit Agreement.
Section 2.13 of the Credit Agreement is hereby amended in its entirety to read
as follows:

                "Section 2.13 Use of Proceeds. The Proceeds of each Borrowing
        shall be used by the Borrower for its general corporate purposes and may
        from time to time be loaned to its Subsidiaries for their working
        capital and general corporate purposes."

                6.      Amendment to Section 3.2 of the Credit Agreement.
Section 3.2 of the Credit Agreement is hereby amended in its entirety to read as
follows:

                "Section 3.2 Conditions Precedent to All Borrowings. The
        obligation of the Banks to fund each request for a Borrowing or to issue
        each Letter of Credit shall be subject to the further conditions
        precedent that on such date:

                        (a)     the representations and warranties contained in
                Article IV hereof are correct in all material respects on and as
                of the date of such Advance as though made on and as of such
                date; and

                        (b)     no event has occurred and is continuing, or
                would result from such Advance, which constitutes a Default or
                an Event of Default."

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                7.      Amendment to Section 4.15 to the Credit Agreement.
Section 4.15 of the Credit Agreement is hereby amended in its entirety to read
as follows:

                "Section 4.15 Acquisition. The Borrower and Entegris Cayman have
        completed the Acquisition in compliance with all material terms of the
        Acquisition Documents. The Borrower and/or Entegris Cayman have the
        title specified in the Acquisition Documents to all assets the subject
        of the Acquisition and such assets are free and clear of all mortgages,
        security interests, liens and encumbrances, except those specifically
        contemplated by the Acquisition Documents."

                8.      Amendment to Section 5.1(a) of the Credit Agreement.
Section 5.1(a) of the Credit Agreement is hereby amended by deleting the text
"Exhibit B to the Second Amendment" therein and inserting the text "Exhibit E"
in its place.

                9.      Amendments to Section 5.1(b) of the Credit Agreement.
The following amendments are hereby made to Section 5.1(b) of the Credit
Agreement.

                        (a)     The text "Exhibit C to the Second Amendment" is
                hereby deleted and the text "Exhibit F" is hereby inserted in
                its place.

                        (b)     The text "in Sections 5.8 through 5.10" at the
                end of such Section is hereby deleted and the text "the
                Financial Covenants" is hereby inserted in its place.

                10.     Amendment to Section 5.8 of the Credit Agreement.
Section 5.8 of the Credit Agreement is hereby amended to read in its entirety as
follows:

                "Section 5.8 Fixed Charge Coverage Ratio. As of each Covenant
        Computation Date, the Borrower and its Subsidiaries, on a consolidated
        basis, will maintain a Fixed Charge Coverage Ratio of not less than 1.10
        to 1.00."

                11.     Amendment to Section 5.9 of the Credit Agreement.
Section 5.9 of the Credit Agreement is hereby amended to read in its entirety as
follows:

                "Section 5.9 Leverage Ratio. As of each Covenant Computation
        Date, the Borrower and its Subsidiaries, on a consolidated basis, will
        maintain a Leverage Ratio of not more than 2.25 to 1.00."

                12.     Amendment to Section 5.10 of the Credit Agreement.
Section 5.10 of the Credit Agreement is hereby amended to read in its entirety
as follows:

                "Section 5.10 Minimum Tangible Net Worth. As of each Covenant
        Computation Date occurring on or after February 28, 2003, the Borrower
        and its Subsidiaries, on a consolidated basis, will maintain a Tangible
        Net Worth of not less than the sum of $201,000,000 plus (a) fifty
        percent (50%) of the Net Income (unless

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        such amount is negative, in which case it shall be ignored for purposes
        of this Section) realized by the Borrower and its Subsidiaries, on a
        consolidated basis, for each Covenant Computation Period commencing on
        or after December 1, 2002, and (b) fifty percent (50%) of the net cash
        proceeds received by the Borrower and/or its Subsidiaries from any
        equity offering made by the Borrower and/or its Subsidiaries at any time
        on or after December 1, 2002."

                13.     Amendment of Section 5.11 of the Credit Agreement.
Section 5.11 of the Credit Agreement is hereby amended in its entirety to read
as follows:

                "Section 5.11 Minimum Domestic Tangible Net Worth. As of each
        Covenant Computation Date occurring on or after February 28, 2003, the
        Borrower, its Domestic Subsidiaries and the Guarantors, will maintain,
        on a consolidated basis, a Domestic Tangible Net Worth of not less than
        $125,000,000."

                14.     Amendment of Section 5.12 to the Credit Agreement.
Section 5.12 of the Credit Agreement is hereby amended in its entirety to read
as follows:

                "Section 5.12 Minimum Cash and Cash Equivalents. The Borrower
        and its Subsidiaries, on a consolidated basis, will at all times own and
        maintain cash and cash equivalents in an aggregate amount of not less
        than $75,000,000 and the Borrower will at all times cause not less than
        $40,000,000 of such amount to be held and maintained as Domestic Cash."

                15.     Addition of Section 5.13 to the Credit Agreement.
Section 5.13 of the Credit Agreement is hereby added as follows:

                "Section 5.13 Domestic Subsidiaries. The Borrower will cause
        each of its Domestic Subsidiaries, as and when created or acquired, to
        become a Guarantor and to, concurrent with such creation or acquisition,
        execute and deliver a Guaranty to the Agent for the benefit of the
        Banks."

                16.     Addition of Section 5.14 to the Credit Agreement.
Section 5.14 of the Credit Agreement is hereby added as follows:

                "Section 5.14 Opinion of Counsel to Asyst. The Borrower will use
        commercially reasonable efforts to cause counsel to Asyst in connection
        with the Acquisition to provide a reliance letter to the Agent and the
        Banks permitting the Agent and the Banks to rely on such counsel's
        opinion letter delivered in connection with the Acquisition within 30
        days of the date of the Fourth Amendment."

                17.     Amendment of Section 6.1 of the Credit Agreement. Clause
(a) of Section 6.1 of the Credit Agreement is hereby amended in its entirety to
read as follows:

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                "(a) mortgages, deeds of trust, pledges, liens, security
        interests and assignments in existence on the effective date of the
        Fourth Amendment and listed in Schedule 6.1 (including any subsequent
        extension or renewal of such mortgages, deeds of trust, pledges, liens,
        security interests and assignments to the extent (i) the related
        extension or renewal of the Debt secured thereby is otherwise permitted
        under this Agreement, (ii) the principal amount secured thereby is not
        increased above the amount outstanding immediately prior to such
        extension or renewal, and (iii) the property subject thereto is not
        increased)."

                18.     Amendment of Section 6.2 of the Credit Agreement.
Clauses (e), (h) and (i) of Section 6.2 of the Credit Agreement are hereby
amended in their entirety to read and clause (j) is hereby added thereto as
follows:

                        (e)     Subordinated Debt, or renewals thereof, provided
                that (a) it is subordinated to the prior payment of all
                indebtedness, reimbursement obligations and guaranties of the
                Borrower and its Subsidiaries in favor of the Banks on terms and
                conditions approved in writing by the Banks and (b) the
                aggregate amount of Subordinated Debt at any one time
                outstanding does not exceed $5,000,000 (all Subordinated Debt is
                properly reflected in Schedule 6.2);

                        (h)     Indebtedness for borrowed money in foreign
                currencies in an aggregate principal amount not to exceed at any
                time $30,000,000 (all Indebtedness for borrowed money in foreign
                currencies is properly reflected in Schedule 6.2);

                        (i)     Indebtedness for borrowed money not permitted by
                any other subsection of this Section 6.2 in an aggregate
                principal amount not to exceed at any time $10,000,000; and

                        (j)     Indebtedness arising from Intercompany Loans.

                19.     Amendment of Section 6.3 of the Credit Agreement. Clause
(c) of Section 6.3 of the Credit Agreement is hereby amended in its entirety to
read as follows:

                "(c) guaranties, endorsements and other direct or contingent
        liabilities in connection with the obligations of other Persons listed
        in Schedule 6.3, together with any extension, renewal or replacement
        thereof (so long as such indebtedness is not increased above the amount
        outstanding immediately prior to giving effect to any such extension,
        renewal or replacement);"

                20.     Amendment of Section 6.4 of the Credit Agreement.
Section 6.4 of the Credit Agreement is hereby amended in its entirety to read as
follows:

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                '"Section 6.4 Investments. The Borrower will not, and will not
        permit any Subsidiary to, purchase or hold beneficially any stock or
        other securities or evidences of indebtedness of, make or permit to
        exist any loans or advances to, or create or acquire any Subsidiary or
        make any investment or acquire any interest whatsoever in, any other
        Person, except:

                        (a)     investments (either directly or through mutual
                funds) in direct obligations of the United States of America or
                any agency or instrumentality thereof whose obligations
                constitute the full faith and credit obligations of the United
                States of America having a maturity of one year or less,
                commercial paper issued by a U.S. corporation rated "A-1" or
                "A-2" by Standard & Poors Rating Group or "P-1" or "P-2" by
                Moody's Investors Service, certificates of deposit or bankers'
                acceptances having a maturity of one year or less issued by
                members of the Federal Reserve System having deposits in excess
                of $100,000,000 (which certificates of deposit or bankers'
                acceptances are fully insured by the Federal Deposit Insurance
                Corporation) and such other investments as the Borrower shall
                request and the Banks shall approve in writing;

                        (b)     any investment by the Borrower or any of its
                Subsidiaries in the stock of any Subsidiary or in the stock of
                any Affiliate set forth on Schedule 4.4;

                        (c)     Intercompany Loans;

                        (d)     loans to officers and employees of the Borrower
                or officers and employees of any of its Subsidiaries not
                exceeding at any one time an aggregate of $500,000;

                        (e)     travel advances to officers and employees of the
                Borrower or officers and employees any of its Subsidiaries or
                any other similar advances in the ordinary course of business;

                        (f)     advances in the form of progress payments,
                prepaid rent or security deposits or any other similar advances
                in the ordinary course of business;

                        (g)     the acquisition of the stock or assets of
                another Person so long as, prior to each such acquisition, the
                Borrower has submitted to the Agent financial projections,
                certificates and other documentation which establish that, after
                giving effect to such acquisition:

                                        (A)   the Borrower and its Subsidiaries
                                              will be in compliance with all
                                              covenants and terms of this

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                                              Agreement and the other Loan
                                              Documents through the Maturity
                                              Date;

                                        (B)   the acquired business of such
                                              Person is in the same line of
                                              business as an existing business
                                              of the Borrower or its
                                              Subsidiaries; and

                                        (C)   all consideration (whether in the
                                              form of cash paid, indebtedness
                                              assumed or otherwise) given by the
                                              Borrower and its Subsidiaries for
                                              acquisitions permitted under this
                                              Section 6.4(g) shall not exceed an
                                              aggregate amount of $25,000,000
                                              during the fiscal year in which
                                              such acquisition occurs (provided,
                                              however, that the Acquisition
                                              shall not be counted for purposes
                                              of determining compliance with the
                                              $25,000,000 limitation set forth
                                              in this Section 6.4(g)(C)); and

                        (h)     the Acquisition."

                21.     Amendment of Section 6.6 of the Credit Agreement.
Clauses (b) and (c) of Section 6.6 of the Credit Agreement are hereby amended in
their entirety to read and clause (d) is hereby added as follows:

                        (b)     sales, leases and assignments by the Borrower or
                any of its Subsidiaries of its properties in the ordinary course
                of its business;

                        (c)     sales or leases by the Borrower or any of its
                Subsidiaries of its surplus, obsolete or worn-out properties; or

                        (d)     Intercompany Loans."

                22.     Amendment of Section 6.8 of the Credit Agreement.
Section 6.8 of the Credit Agreement is hereby amended to delete the reference to
"Section 6.4(g)" at the end of such Section and to insert the text "Section 6.4"
in its place.

                23.     Amendment of Section 7.1 of the Credit Agreement.
Section 7.1 of the Credit Agreement is hereby amended by amending clauses (d)
and (n) thereof to read in their entirety as follows:

                "(d) default in the performance, or breach, of any covenant or
        agreement on the part of the Borrower contained in any Financial
        Covenant or in Article VI; or"

                                     - 12 -

<PAGE>

                "(n) any Guarantor shall repudiate, purport to revoke or fail to
        perform any of such Guarantor's obligations under its Guaranty or any
        other Loan Document to which it is a party; or"

                24.     Revised Schedules. The following Schedules and/or
Exhibits to the Credit Agreement (whether originally attached to the Credit
Agreement or subsequently becoming part of the Credit Agreement by amendment)
are hereby replaced in their entirety as follows:

                (a)     Exhibit A to the Second Amendment (originally given in
        replacement of Exhibit A to the Credit Agreement) is hereby replaced by
        Exhibit A to the Fourth Amendment, with the effect that Exhibit A to the
        Fourth Amendment shall hereafter constitute Exhibit A for all purposes
        of the Credit Agreement.

                (b)     Exhibit B to the Second Amendment (originally given in
        replacement of Exhibit E to the Credit Agreement) is hereby replaced by
        Exhibit B to the Fourth Amendment, with the effect that Exhibit B to the
        Fourth Amendment shall hereafter constitute Exhibit E for all purposes
        of the Credit Agreement.

                (c)     Exhibit C to the Second Amendment (originally given in
        replacement of Exhibit F to the Credit Agreement) is hereby replaced by
        Exhibit C to the Fourth Amendment, with the effect that Exhibit C to the
        Fourth Amendment shall hereafter constitute Exhibit F for all purposes
        of the Credit Agreement.

                (d)     Schedule 4.4 to the Second Amendment (originally given
        in replacement of Schedule 4.4 to the Credit Agreement) is hereby
        replaced by Schedule 4.4 to the Fourth Amendment, with the effect that
        Schedule 4.4 to the Fourth Amendment shall hereafter constitute Schedule
        4.4 for all purposes of the Credit Agreement.

                (e)     Schedule 6.1 to the Second Amendment (originally given
        in replacement of Schedule 6.1 to the Credit Agreement) is hereby
        replaced by Schedule 6.1 to the Fourth Amendment, with the effect that
        Schedule 6.1 to the Fourth Amendment shall hereafter constitute Schedule
        6.1 for all purposes of the Credit Agreement.

                (f)     Schedule 6.2 to the Second Amendment (originally given
        in replacement of Schedule 6.2 to the Credit Agreement) is hereby
        replaced by Schedule 6.2 to the Fourth Amendment, with the effect that
        Schedule 6.2 to the Fourth Amendment shall hereafter constitute Schedule
        6.2 for all purposes of the Credit Agreement.

                (g)     Schedule 6.3 to the Second Amendment (originally given
        in replacement of Schedule

                                     - 13 -

<PAGE>

        6.3 to the Credit Agreement) is hereby replaced by Schedule 6.3 to the
        Fourth Amendment, with the effect that Schedule 6.3 to the Fourth
        Amendment shall hereafter constitute Schedule 6.3 for all purposes of
        the Credit Agreement.

                25.     Amendment Fee. In consideration of the Banks'
entering into this Amendment, the Borrower shall pay to the Agent, for the
ratable benefit of the Banks in accordance with their Percentages, a facility
increase fee of 0.125% of the increase in the Revolving Commitment Amount
effected by this Amendment. Such fee shall be deemed fully earned by the Banks'
execution and delivery of this Amendment.

                26.     Conditions Precedent. This Amendment shall become
effective when the Agent shall have received the following, each in form and
content acceptable to the Agent in its sole discretion:

                (a)     This Amendment duly executed on behalf of the Borrower,
        the Banks and the Agent;

                (b)     A Revolving Note duly executed on behalf of the Borrower
        in favor of each Bank in the amount of such Bank's Revolving Commitment,
        issued in substitution for and replacement of, but not payment of such
        Bank's Revolving Note (as defined in the Second Amendment);

                (c)     Copies of the executed Acquisition Documents;

                (d)     A certified copy of the resolutions of the board of
        directors of the Borrower evidencing approval of the Amendment and all
        matters contemplated hereby;

                (e)     A signed copy of a certificate of the Secretary or an
        Assistant Secretary of the Borrower, which shall certify (i) the names
        of the officers of the Borrower authorized to sign the Amendment and the
        documents to be executed by the Borrower in connection therewith,
        together with the true signatures of such officers, (ii) the resolutions
        described in (e) above, and (iii) that the Articles of Incorporation and
        Bylaws of the Borrower certified to the Agent and the Banks in
        connection with the Consent remain in full force and effect and have not
        been amended or modified since such certification;

                (f)     A certificate of good standing of the Borrower, dated
        not more than thirty (30) days prior to the date hereof;

                (g)     A certified copy of the resolutions of the sole
        shareholder of NT International evidencing approval of its Guaranty and
        all matters contemplated thereby;

                                     - 14 -

<PAGE>

                (h)     Copies of the Articles of Incorporation and Bylaws of NT
        International certified by the Secretary or Assistant Secretary of the
        Borrower, the sole shareholder of NT International, as being true and
        correct copies thereof;

                (i)     A signed copy of a certificate of the Secretary or an
        Assistant Secretary of the Borrower, the sole shareholder of NT
        International, which shall certify the names of the officers of NT
        International authorized to sign its Guaranty and the documents to be
        executed by NT International in connection therewith, together with the
        true signatures of such officers.

                (j)     A certificate of good standing of NT International,
        dated not more than thirty (30) days prior to the date hereof;

                (k)     A certified copy of the resolutions of the sole
        shareholder of Entegris Custom Products evidencing approval of its
        Guaranty and all matters contemplated thereby;

                (l)     Copies of the Articles of Incorporation and Bylaws of
        Entegris Custom Products certified by the Secretary or Assistant
        Secretary of the Borrower, the sole shareholder of Entegris Custom
        Products, as being true and correct copies thereof;

                (m)     A signed copy of a certificate of the Secretary or an
        Assistant Secretary of the Borrower, the sole shareholder of Entegris
        Custom Products, which shall certify the names of the officers of
        Entegris Custom Products authorized to sign its Guaranty and the
        documents to be executed by Entegris Custom Products in connection
        therewith, together with the true signatures of such officers;

                (n)     A certificate of good standing of Entegris Custom
        Products, dated not more than thirty (30) days prior to the date hereof;

                (o)     Current searches of appropriate filing offices showing
        that no state or federal tax liens have been filed and remain in effect
        against the Borrower, NT International or Entegris Custom Products and
        that no financing statements or other notifications or filings have been
        filed and remain in effect against the Borrower, NT International or
        Entegris Custom Products other than those for which the Agent has
        received an appropriate release, termination or satisfaction or those
        permitted in accordance with Section 6.1 of the Credit Agreement;

                (p)     A signed copy of an opinion of counsel to the Borrower,
        NT International and Entegris Custom Products, addressed to the Agent
        and the Banks; and

                (q)     The Guaranties of NT International and Entegris Custom
        Products, duly executed on behalf of such parties.

                                     - 15 -

<PAGE>

                27.     Reference to and Effect on the Credit Agreement and the
other Loan Documents. Except as otherwise amended by this Amendment, all of the
terms and conditions of the Credit Agreement and the other Loan Documents prior
to giving effect to this Amendment shall remain in full force and effect in
accordance with their terms.

                28.     Counterparts. This Amendment may be executed in any
number of counterparts, each of which shall be deemed to be an original and all
of which counterparts taken together shall constitute but one and the same
instrument.

                29.     Borrower Release. The Borrower hereby absolutely and
unconditionally releases and forever discharges the Agent and each of the Banks,
and any and all participants, parent corporations, subsidiary corporations,
affiliated corporations, insurers, indemnitors, successors and assigns thereof,
together with all of the present and former directors, officers, agents and
employees of any of the foregoing (the "Released Parties"), from any and all
claims, demands or causes of action of any kind, nature or description, whether
arising in law or equity or upon contract or tort or under any state or federal
law or otherwise, which the Borrower has had, now has or has made claim to have
against such Released Party for or by reason of any act, omission, matter, cause
or thing whatsoever arising from the beginning of time to and including the date
of this Amendment in connection with or related to the transactions evidenced by
the Loan Documents, whether such claims, demands and causes of action are mature
or unmatured or known or unknown.

                30.     No Waiver. The execution of this Amendment shall not be
deemed to be a waiver of any Default or Event of Default under the Credit
Agreement, whether or not known to the Agent and/or the Banks and whether or not
existing on the date of this Amendment.

                31.     Representations and Warranties of the Borrower. The
Borrower hereby represents and warrants to the Agent and the Banks as follows:

                (a)     The Borrower has all requisite power and authority to
        execute this Amendment and the Revolving Notes and to perform all of its
        obligations under the Credit Agreement, as amended by this Amendment,
        and the Credit Agreement, as amended by this Amendment, this Amendment,
        the Revolving Notes and the other Loan Documents executed on behalf of
        the Borrower have been duly executed and delivered by the Borrower and
        constitute the legal, valid and binding obligations of the Borrower,
        enforceable in accordance with their respective terms.

                (b)     The execution, delivery and performance by the Borrower
        of the Credit Agreement, as amended by this Amendment, the Amendment,
        the Revolving Notes and the other Loan Documents executed on behalf of
        the Borrower have been duly authorized by all necessary corporate action
        and do not (i) require any authorization, consent or approval by any
        governmental department, commission, board, bureau, agency or
        instrumentality, domestic or foreign, (ii) violate any provision of any
        law,

                                     - 16 -

<PAGE>

        rule or regulation or of any order, writ, injunction or decree presently
        in effect, having applicability to the Borrower, or the Articles of
        Incorporation or Bylaws of the Borrower, or (iii) result in a breach of
        or constitute a default under any indenture or loan or credit agreement
        or any other agreement, lease or instrument to which the Borrower is a
        party or by which it or its properties may be bound or affected.

                (c)     All of the representations and warranties contained in
        Article IV of the Credit Agreement are correct on and as of the date
        hereof as though made on and as of such date, except to the extent that
        such representations and warranties relate solely to an earlier date.

                32.     References. All references in the Credit Agreement to
"this Agreement" shall be deemed to refer to the Credit Agreement as amended by
this Amendment; and any and all references in any of the other Loan Documents to
the "Credit Agreement" shall be deemed to refer to the Credit Agreement as
amended by this Amendment. All references to schedules or exhibits in the Credit
Agreement shall be deemed to include the amendments to such schedules and
exhibits effected hereby.

                             Signature Page Follows

                                     - 17 -

<PAGE>

                IN WITNESS WHEREOF, the parties hereto have caused this
Amendment to be executed by their respective officers thereunto duly authorized
as of the date first above written.

Address:                                ENTEGRIS, INC.
3500 Lyman Boulevard
Chaska, Minnesota 55318
Attn:  John Villas                      By        /s/ James E. Dauwalter
Telecopy No. (952) 556-8644                -------------------------------------
                                            Its     Chief Executive Officer
                                                --------------------------------

                                        And

                                        By            /s/ John Villas
                                           -------------------------------------
                                            Its     Chief Financial Officer
                                                --------------------------------

Address:                                WELLS FARGO BANK, NATIONAL
7900 Xerxes Avenue South                 ASSOCIATION, , as a Bank and as Agent
MAC N9307-013
Bloomington, Minnesota  55431
Attn:  Richard G. Trembley
Telecopy No. (612) 316-1621

Revolving Commitment:  $20,000,000      By        /s/ Richard G. Trembley
Percentage:  50%                           -------------------------------------
                                            Its          Vice President
                                                --------------------------------


Address:                                HARRIS TRUST AND SAVINGS BANK, as
111 West Monroe                          Bank
P.O. Box 755
Chicago, Illinois  60690
Attn:  Michael M. Fordney
Telecopy No. (312) 293-5040

Revolving Commitment:  $20,000,000      By        /s/ Michael M. Fordney
Percentage:  50%                           -------------------------------------
                                            Its          Vice President
                                                --------------------------------

                                     - 18 -

             Signature Page to Fourth Amendment to Credit Agreement