<PAGE>   1
                                                                     Exhibit 4.1


                   INTEGRATED PROCESS EQUIPMENT CORP., Company

                         SPEEDFAM-IPEC, INC., Guarantor

                                       and

             STATE STREET BANK AND TRUST COMPANY OF CALIFORNIA, N.A.
                                     Trustee



                          FIRST SUPPLEMENTAL INDENTURE

                            Dated as of April 6, 1999

                                       To

                                    INDENTURE

                         Dated as of September 15, 1997



                                   Relating to

                       Integrated Process Equipment Corp.

                      6-1/4% Convertible Subordinated Notes
                                    due 2004
<PAGE>   2
      This FIRST SUPPLEMENTAL INDENTURE, dated as of the 6th day of April, 1999,
by and among INTEGRATED PROCESS EQUIPMENT CORP., a corporation duly organized
and existing under the laws of the State of Delaware (the "Company"),
SPEEDFAM-IPEC, INC., a corporation duly organized and existing under the laws of
the State of Illinois (the "Guarantor"), and STATE STREET BANK AND TRUST COMPANY
OF CALIFORNIA, N.A., a national banking association organized under the laws of
the United States of America, and trustee under the Indenture (as hereinafter
defined) (the "Trustee").

                                   WITNESSETH:

      WHEREAS, the Company and the Trustee have heretofore entered into that
certain Indenture, dated as of September 15, 1997, providing for the issuance of
6-1/4% Convertible Subordinated Debentures due 2004 (the "Notes"), in the
aggregate principal amount not to exceed $115,000,000 (such Indenture, as
further supplemented or amended in accordance with its terms, herein the
"Indenture");

      WHEREAS, the Company, SpeedFam, Inc., a Delaware corporation ("Merger
Sub"), and the Guarantor have entered into an Agreement and Plan of Merger,
dated as of November 19, 1998, as amended (the "Merger Agreement"), pursuant to
which Merger Sub will merge (the "Merger") with and into the Company, and the
Company will then become a wholly-owned subsidiary of the Guarantor, and each
share of the Company's Common Stock outstanding immediately prior to the
effective time of the Merger (the "Effective Time") will be converted into the
right to receive 0.71 shares of Common Stock of the Guarantor in accordance with
the terms of the Merger Agreement;

      WHEREAS, Section 15.6 of the Indenture provides that, "If any of the
following events occur, namely (i) any reclassification or change of the
outstanding shares of Common Stock (other than a subdivision or combination to
which Section 15.5(c) applies), (ii) any consolidation, merger or combination of
the Company with another corporation as a result of which holders of Common
Stock shall be entitled to receive stock, securities or other property or assets
(including cash) with respect to or in exchange for such Common Stock, or (iii)
any sale or conveyance of the properties and assets of the Company as, or
substantially as, an entirety to any other corporation as a result of which
holders of Common Stock shall be entitled to receive stock, securities or other
property or assets (including cash) with respect to or in exchange for such
Common Stock, then the Company or the successor or purchasing corporation, as
the case may be, shall execute with the Trustee a supplemental indenture (which
shall comply with the Trust Indenture Act as in force at the date of execution
of such supplemental indenture) providing that such Note shall be convertible
into the kind and amount of shares of stock and other securities or property or
assets (including cash) receivable upon such reclassification, change,
consolidation, merger, combination, sale or conveyance by a holder of a number
of shares of Common Stock issuable upon conversion of such Notes (assuming, for
such purposes, a sufficient number of authorized shares of Common Stock
available to convert all such Notes) immediately prior to such reclassification,
change, consolidation, merger, combination, sale or conveyance assuming such
holder of Common Stock did not exercise
<PAGE>   3
his rights of election, if any, as to the kind or amount of securities, cash or
other property receivable upon such consolidation, merger, statutory exchange,
sale or conveyance (provided that, if the kind or amount of securities, cash or
other property receivable upon such consolidation, merger, statutory exchange,
sale or conveyance is not the same for each share of Common Stock in respect of
which such rights or election shall not have been exercised ("nonelecting
share")), then for purposes of this Section 15.6 the kind and amount of
securities, cash or other property receivable upon such consolidation, merger,
statutory exchange, sale or conveyance for each non-electing share shall be
deemed to be the kind and amount so receivable or share by a plurality of the
non-electing shares. Such supplemental indenture shall provide for adjustments
which shall be as nearly equivalent as may be practicable to the adjustments
provided for in this Article;"

      WHEREAS, Section 12.1 of the Indenture permits the Company to merge with
another corporation provided certain conditions are satisfied;

      WHEREAS, the Guarantor is willing to guarantee, on a subordinated basis as
set forth more fully herein, the payment of the principal of, premium, if any,
and interest on the Notes in order to preserve the exemption available under
Section 3(a)(9) of the Securities Act for the conversion of Notes into Common
Stock;

      WHEREAS, Section 11.1 of the Indenture authorizes the Company, with the
consent of the Trustee, to supplement or amend the Indenture to comply with
Section 15.6 hereof and to correct or supplement provisions of or make other
provisions with respect to matters or questions arising under the Indenture that
do not adversely affect the rights of any Noteholder;

      WHEREAS, the Company and the Guarantor desire to execute a supplemental
indenture that complies with Section 11.1 of the Indenture;

      WHEREAS, all acts and things necessary to make this First Supplemental
Indenture a valid and binding agreement for the purposes and objects herein
expressed have been duly done and performed, and the execution of this First
Supplemental Indenture have been, in all respects, duly authorized;

      WHEREAS, the foregoing recitals are made as representations or
statements of fact by the Company or the Guarantor, as applicable, and not by
the Trustee; and

      WHEREAS, the Trustee is authorized by Section 11.1 of the Indenture to
execute this First Supplemental Indenture without the consent of the holders of
the Notes;

      NOW, THEREFORE, in consideration of the premises and of other good and
valuable consideration, the receipt of which is hereby acknowledged, the
Company and the Guarantor hereby covenant and agree with the Trustee, for the
equal and proportionate benefit of the respective holders from time to time
of the Notes, as follows:


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                                   ARTICLE I

             DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION

      SECTION 1.1 The [Form of Face of Note] in the Indenture is hereby amended
by deleting the reference to "Common Stock of the Company" that appears in the
second paragraph thereof and inserting in lieu thereof the words "Common Stock."

      SECTION 1.2 The [Form of Reverse of Note] in the Indenture is hereby
amended by:

            (a) Deleting the reference to "Common Stock of the Company" in the
third paragraph thereof and inserting in lieu thereof the words "Common Stock;"

            (b) Deleting the reference to "Company's Common Stock" that appears
in the twelfth paragraph thereof and inserting in lieu thereof the words "Common
Stock;"

            (c) Deleting the reference to "Common Stock of the Company" that
appears in the thirteenth paragraph thereof and inserting in lieu thereof the
words "Common Stock;" and

            (d) Deleting the sixteenth paragraph and inserting in lieu thereof
the following paragraph:

            No recourse for the payment of the principal of or any premium or
      interest on this Note, or for any claim based hereon or otherwise in
      respect hereof, and no recourse under or upon any obligation, covenant or
      agreement of the Company or the Guarantor in the Note or any indenture
      supplemental thereto or in any Note, or because of the creation of any
      indebtedness represented thereby or the guarantee by the Guarantor
      thereof, shall be had against any incorporator, stockholder, officer or
      director, as such, past, present or future, of the Company or the
      Guarantor or of any respective successor corporation, either directly or
      through the Company or the Guarantor or any respective successor
      corporation, whether by virtue of any constitution, statute or rule of law
      or by the enforcement of any assessment or penalty or otherwise, all such
      liability being, by the acceptance hereof and as part of the consideration
      for the issue hereof, expressly waived and released; provided, however,
      that the foregoing shall not affect or impair the obligations of the
      Guarantor hereunder.

      SECTION 1.3 The [Form of Conversion Notice] in the Indenture is hereby
amended by deleting the phrase "Common Stock of Integrated Process Equipment
Corp." and inserting in lieu thereof the words "Common Stock."

      SECTION 1.4 The terms defined in this Section 1.4 (except as herein
otherwise expressly provided or unless the context otherwise requires) for all
purposes of this First Supplemental Indenture shall have the respective meanings
specified in this Section 1.4. All other terms used in this First Supplemental
Indenture which are defined in the Indenture, the Trust Indenture Act or which
are by reference therein defined in the Securities Act (except as herein
otherwise expressly provided or unless the context otherwise requires) shall
have the meanings assigned to such terms in


                                      -3-
<PAGE>   5
said Trust Indenture Act and in said Securities Act as in force at the date of
the execution of this First Supplemental Indenture. The words "herein," "hereof"
and "hereunder," and words of similar import, refer to this First Supplemental
Indenture as a whole and not to any particular Article, Section or other
Subsection. The terms defined in this Article include the plural as well as the
singular.

            (a) The definitions of the following words contained in Section 1.1
of the Indenture, are hereby amended by deleting them in their entirety and
inserting in lieu thereof the following respective definitions:

            COMMON STOCK: The term "Common Stock" shall mean any stock of any
      class of Guarantor which has no preference in respect of dividends or of
      amounts payable in the event of any voluntary or involuntary liquidation,
      dissolution or winding up of the Guarantor and which is not subject to
      redemption by the Guarantor. Subject to the provisions of Section 15.6,
      however, shares issuable on conversion of Notes shall include only shares
      of the class designated as Common Stock of the Guarantor at the date of
      this First Supplemental Indenture or shares of any class or classes
      resulting from any reclassification or reclassifications thereof and which
      have no preference in respect of dividends or of amounts payable in the
      event of any voluntary or involuntary liquidation, dissolution or winding
      up of the Guarantor and which are not subject to redemption by the
      Guarantor; provided that if at any time there shall be more than one such
      resulting class, the shares of each such class then so issuable shall be
      substantially in the proportion which the total number of shares of such
      class resulting from all such reclassifications bears to the total number
      of shares of all such classes resulting from all such reclassifications.

            CORPORATE TRUST OFFICE: The term "Corporate Trust Office", or other
      similar term, shall mean the principal office of the Trustee at which at
      any particular time its corporate trust business shall be principally
      administered, which office is, at the date as of which this Indenture is
      dated, located at 633 West Fifth Street, 12th Floor, Los Angeles,
      California 90071, Attention: Corporate Trust Department.

            REFERENCE MARKET PRICE: The term "Reference Market Price" shall
      initially mean $28.17, and in the event of any adjustment to the
      Conversion Price pursuant to Sections 15.5(a), (b), (c), (d), (e), (f) or
      (g), the Reference Market Price shall also be adjusted so that the ratio
      of the Reference Market Price to the Conversion Price after giving effect
      to any such adjustment shall always be the same as the ratio of $28.17 to
      the Conversion Price specified in the form of Note herein above set forth
      (without regard to any adjustment thereto).


            (b) Section 1.1 of the Indenture is hereby amended to add the
following definitions:

            DESIGNATED GUARANTOR SENIOR INDEBTEDNESS: The term "Designated
      Guarantor Senior Indebtedness" shall mean Guarantor Senior Indebtedness
      under the Guarantor Loan Agreement or any other particular Guarantor
      Senior Indebtedness in which the instrument creating or evidencing the
      same or the assumption or guarantee thereof (or related agreements


                                      -4-
<PAGE>   6
      or documents to which the Company is a party) expressly provides that such
      Guarantor Senior Indebtedness shall be "Designated Guarantor Senior
      Indebtedness" for purposes of this Indenture (provided that such
      instrument, agreement or other document may place limitations and
      conditions on the right of such Guarantor Senior Indebtedness to exercise
      the rights of Designated Guarantor Senior Indebtedness). If any payment
      made to any holder of any Designated Guarantor Senior Indebtedness or its
      Representative with respect to such Designated Guarantor Senior
      Indebtedness is rescinded or must otherwise be returned by such holder or
      Representative upon the insolvency, bankruptcy or reorganization of the
      Guarantor or otherwise, the reinstated Indebtedness of the Guarantor
      arising as a result of such rescission or return shall constitute
      Designated Guarantor Senior Indebtedness effective as of the date of such
      rescission or return.

            GUARANTOR:  The term "Guarantor" shall mean SpeedFam-Ipec, Inc.,
      an Illinois corporation, and shall include its successors and assigns.

            GUARANTOR LOAN AGREEMENT: The term "Guarantor Loan Agreement" shall
      mean the credit facility to be entered into between the Guarantor and
      First Chicago Capital Markets, Inc., a Bank One company, as further
      amended, amended and restated, supplemented or otherwise modified from
      time to time.

            GUARANTOR SENIOR INDEBTEDNESS: The term "Guarantor Senior
      Indebtedness" shall mean the principal of, premium, if any, and interest
      on, and any other payment due pursuant to the terms of any instrument
      (including, without limitation, fees, expenses, collection expenses
      (including attorneys' fees), interest yield amounts, post-petition
      interest and taxes) creating, securing or evidencing any of the following,
      whether outstanding at the date hereof or hereafter incurred or created:

                  (a) all indebtedness of the Guarantor for money borrowed
            (including any indebtedness secured by a mortgage, conditional sales
            contract or other lien which is (i) given to secure all or part of
            the purchase price of property subject thereto, whether given to the
            vendor of such property or to another or (ii) existing on property
            at the time of acquisition thereof);

                  (b) all indebtedness of the Guarantor evidenced by notes,
            debentures, bonds or other similar instruments;

                  (c) all indebtedness or other obligations of the Guarantor
            with respect to interest rate swap agreements, cap, floor and collar
            agreements, spot and forward contracts, and similar agreements and
            arrangements;

                  (d) all indebtedness or other obligations of the Guarantor
            with respect to letters of credit (including reimbursement
            obligations with respect thereto), bank guarantees and bankers'
            acceptances;


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<PAGE>   7
                  (e) all lease obligations of the Guarantor which are
            capitalized on the books of the Guarantor in accordance with
            generally accepted accounting principles;

                  (f) all indebtedness of others of the kinds described in the
            preceding clauses (a), (b), (c) or (d) and all lease obligations of
            others of the kind described in the preceding clause (e) assumed by
            or guaranteed in any manner by the Guarantor or in effect guaranteed
            by the Guarantor through an agreement to purchase, contingent or
            otherwise; and

                  (g) all renewals, extensions or refundings of indebtedness of
            the kinds described in any of the preceding clauses (a), (b), (c),
            (d), or (f) and all renewals or extensions of lease obligations of
            the kinds described in either of the preceding clauses (e) or (f);

unless, in the case of a particular indebtedness, lease, renewal, extension or
refunding, the instrument or lease creating or evidencing the same or the
assumption or guarantee of the same expressly provides that such indebtedness,
lease, renewal, extension or refunding is not superior in right of payment to or
is pari passu with or is subordinated or junior to, the Guarantor's obligations
under the Guaranty. Notwithstanding the foregoing, Guarantor Senior Indebtedness
shall not include: (i) indebtedness evidenced by the Guaranty or otherwise in
respect of the Notes; (ii) any indebtedness or lease obligation of any kind of
the Guarantor to any subsidiary of the Guarantor; and (iii) indebtedness for
trade payables or constituting the deferred purchase price of assets or services
created or assumed by the Guarantor in the ordinary course of business.

            GUARANTY:  The term "Guaranty" shall mean the guarantee of the
      Guarantor pursuant to Section 17.1 hereof.

            SUBSIDIARY: The term "subsidiary" of any specified person shall mean
      (i) a corporation a majority of whose capital stock with voting power
      under ordinary circumstances, to elect directors is at the time directly
      or indirectly owned by such person, or (ii) any other person (other than a
      corporation) in which such person or such person and a subsidiary or
      subsidiaries of such person or a subsidiary or subsidiaries of such person
      directly or indirectly, at the date of determination thereof, has at least
      majority ownership.

                                   ARTICLE II

                               CONVERSION OF NOTES

      SECTION 2.1 As a result of the Merger and without any action on the part
of the holder of any Note, on and after the Effective Time each $1,000 principal
amount of Notes shall be convertible into shares of Common Stock of the
Guarantor, in accordance with the provisions of Article XV of the Indenture, at
an initial Conversion Price per share of $54.93, such Conversion Price being
subject to subsequent adjustment after the Effective Time in accordance with the
provisions of Article XV of the Indenture.


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      SECTION 2.2 Section 15.2 of the Indenture is hereby amended by adding the
words "or shall cause the Guarantor to" immediately after the words "the Company
shall" that appear in the first sentence of the third paragraph thereof.

      SECTION 2.3 Subsections (a) through (g) of Section 15.5 of the Indenture
are hereby amended by deleting all references therein to "the Company" and
inserting in lieu thereof "the Guarantor."

      SECTION 2.4 Section 15.6 of the Indenture is hereby amended by deleting
the first paragraph of such Section in its entirety and inserting in lieu
thereof the following:

            SECTION 15.6 EFFECT OF RECLASSIFICATION, CONSOLIDATION, MERGER OR
      SALE. If any of the following events occur, namely (i) any
      reclassification or change of outstanding shares of Common Stock (other
      than a subdivision or combination to which Section 15.5(c) applies), (ii)
      any consolidation, merger or combination of the Guarantor with another
      corporation as a result of which holders of Common Stock shall be entitled
      to receive stock, securities or other property or assets (including cash)
      with respect to or in exchange for such Common Stock, or (iii) any sale or
      conveyance of the properties and assets of the Guarantor as, or
      substantially as, an entirety to any other corporation as a result of
      which holders of Common Stock shall be entitled to receive stock,
      securities or other property or assets (including cash) with respect to or
      in exchange for such Common Stock, then the Company or the successor or
      purchasing corporation, as the case may be, shall execute with the Trustee
      a supplemental indenture (which shall conform to the Trust Indenture Act
      as in force at the date of execution of such supplemental indenture)
      providing that such Note shall be convertible into the kind and amount of
      shares of stock and other securities or property or assets (including
      cash) receivable upon such reclassification, change, consolidation,
      merger, combination, sale or conveyance by a holder of a number of shares
      of Common Stock issuable upon conversion of such Notes (assuming, for such
      purposes, a sufficient number of authorized shares of Common Stock
      available to convert all such Notes) immediately prior to such
      reclassification, change, consolidation, merger, combination, sale or
      conveyance assuming such holder of Common Stock did not exercise his
      rights of election, if any, as to the kind or amount of securities, cash
      or other property receivable upon such consolidation, merger, statutory
      exchange, sale or conveyance (provided that, if the kind or amount of
      securities, cash or other property receivable upon such consolidation,
      merger, statutory exchange, sale or conveyance is not the same for each
      share of Common Stock in respect of which such rights or election shall
      not have been exercised ("nonelecting share")), then for purposes of this
      Section 15.6 the kind and amount of securities, cash or other property
      receivable upon such consolidation, merger, statutory exchange, sale or
      conveyance for each non-electing share shall be deemed to be the kind and
      amount so receivable or share by a plurality if the non-electing shares.
      Such supplemental indenture shall provide for adjustments which shall be
      as nearly equivalent as may be practicable to the adjustments provided for
      in this Article.

SECTION 2.5 Section 15.8 of the Indenture is hereby amended by deleting such
Section in its entirety and inserting in lieu thereof the following:


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            SECTION 15.8 RESERVATION OF SHARES; SHARES TO BE FULLY PAID;
      COMPLIANCE WITH GOVERNMENTAL REQUIREMENTS; LISTING OF COMMON STOCK. The
      Company shall use its best efforts to (a) cause the Guarantor to provide,
      free from preemptive rights, out of its authorized but unissued shares or
      shares held in treasury or (b) otherwise make available sufficient shares
      to provide for the conversion of the Notes from time to time as such Notes
      are presented for conversion.

            Before the taking of any action by the Guarantor which would cause
      an adjustment reducing the Conversion Price below the then par value, if
      any, of the shares of Common Stock issuable upon conversion of the Notes,
      the Company shall cause the Guarantor to take all corporate action which
      may, in the opinion of the Company's counsel, be necessary in order that
      the shares of Common Stock issuable or otherwise deliverable upon
      conversion of the Notes may be validly and legally issued or delivered (as
      the case may be) at such adjusted Conversion Price.

            The Company covenants that all shares of Common Stock which may be
      issued or otherwise delivered upon conversion of Notes will, when so
      issued or delivered, be fully paid and nonassessable by the Guarantor and
      the Company and free from all taxes, liens and charges with respect to the
      issue or delivery thereof.

            The Company covenants that if any shares of Common Stock to be
      provided for the purpose of conversion of Notes hereunder require
      registration with or approval of any governmental authority under any
      federal or state law before such shares may be validly issued upon
      conversion, the Company will in good faith and as expeditiously as
      possible endeavor to secure such registration or approval, as the case may
      be.

            The Company further covenants that if at any time Common Stock shall
      be listed on the Nasdaq National Market or any other national securities
      exchange or automated quotation system the Company will, or shall cause
      the Guarantor to, if permitted by the rules of such exchange or automated
      quotation system, list and keep listed so long as the Common Stock shall
      be so listed on such exchange or automated quotation system, all Common
      Stock issuable upon conversion of the Notes; provided, however, that if
      rules of such exchange or automated quotation system permit the Company or
      the Guarantor to defer the listing of such Common Stock until the first
      conversion of the Notes into Common Stock in accordance with the
      provisions of this Indenture, the Company covenants to list such Common
      Stock issuable upon conversion of the Notes in accordance with the
      requirements of such exchange or automated quotation system at such time.

      SECTION 2.6 Section 15.10 of the Indenture is hereby amended by deleting
all references to "the Company" in clauses (a) through (d) thereof and inserting
in lieu thereof the words "the Guarantor."


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<PAGE>   10
                                  ARTICLE III

                       CERTAIN COVENANTS OF THE GUARANTOR

      SECTION 3.1 The Guarantor hereby covenants and warrants that (a)
immediately after the Effective Time, no condition or event shall exist which
constitutes or would, after notice or lapse of time or both, constitute a
Default or an Event of Default (both as defined in the Indenture), (b) it has
complied, or has caused the Company to comply, and will comply, or will cause
the Company to comply, with all applicable provisions of Article XV of the
Indenture and (c) it has been authorized by its Board of Directors, pursuant to
Section 11.1 of the Indenture, to execute this First Supplemental Indenture.

                                   ARTICLE IV

                                GUARANTY OF NOTES

      SECTION 4.1 GUARANTY OF NOTES. The Indenture is hereby amended to add the
following provisions as a new Article XVII to be inserted immediately following
Article XVI of the Indenture. Article XVII shall apply to the Notes only.

                                  ARTICLE XVII
                         SUBORDINATED GUARANTY OF NOTES

      SECTION 17.1 GUARANTY. Subject to the provisions of this Article XVII, the
Guarantor hereby unconditionally guarantees, on a subordinated basis as set
forth more fully in this Article XVII, to each holder of a Note authenticated
and delivered by the Trustee in accordance with this Indenture (i) the due and
punctual payment of the principal of, premium, if any, and interest (including
interest on other amounts which may accrue after the filing against the Company
of a petition under the United States Bankruptcy Code (the "Bankruptcy Code"),
whether or not the obligation to pay interest on such amounts shall be
enforceable against the Company) on such Note, when and as the same shall become
due and payable, whether at maturity, by acceleration or otherwise, the due and
punctual payment of interest on the overdue principal of, premium and interest,
if any, on such Note, to the extent lawful, and the due and punctual performance
of all other obligations of the Company to the holders or the Trustee all in
accordance with the terms of such Note and of this Indenture, and (ii) in the
case of any extension of time of payment or renewal of any such Note or any of
such other obligations, that the same will be promptly paid in full when due or
performed in accordance with the terms of the extension or renewal, at stated
maturity, by acceleration or otherwise. A demand for payment under this Article
XVII shall not be effective prior to forty-eight (48) hours after a demand upon
the Company for full and complete payment of all amounts due and payable under
the Notes, unless such demand upon the Company shall be stayed by operation of
Section 362 of the Bankruptcy Code or otherwise. In all other respects, the
Guarantor hereby agrees that its obligations hereunder shall be absolute and
unconditional, irrespective of, and


                                      -9-
<PAGE>   11
shall be unaffected by, any invalidity, irregularity or unenforceability of any
such Note or this Indenture, any failure to enforce the provisions of any such
Note or this Indenture, any waiver, modification or indulgence granted to the
Company with respect thereto, by the holder of such Note or the Trustee, or any
other circumstances which may otherwise constitute a legal or equitable
discharge of a surety or guarantor. The Guarantor hereby waives diligence,
presentment, filing of claims with a court in the event of merger or bankruptcy
of the Company, any right to require a proceeding first against the Company, the
benefit of discussion, protest or notice with respect to any such Note or the
debt evidenced thereby and all demands whatsoever (except as specified above),
and covenants, that this Guaranty will not be discharged as to any such Note
except by payment in full of the principal thereof, premium if any, and interest
thereon. The Guarantor further agrees that, as between the Guarantor, on the one
hand, and the Noteholder and the Trustee, on the other hand, (i) the maturity of
the obligations guaranteed hereby may be accelerated as provided in Article VII
hereof for the purposes of this Guaranty notwithstanding any stay, injunction or
other prohibition preventing such acceleration in respect of the obligations
guaranteed hereby, provided that notice of such acceleration has been given to
the Guarantor by the Trustee, and (ii) in the event of any declarations of
acceleration of such obligations as provided in Article VII hereof, such
obligations (whether or not due and payable) shall forthwith become due and
payable by the Guarantor for the purpose of this Guaranty.

      The Guarantor shall be subrogated to all rights of the holders of any
Notes against the Company in respect of any amounts paid to the Noteholder by
the Guarantor pursuant to the provisions of this Guaranty; provided that the
Guarantor shall not be entitled to enforce, or to receive any payments arising
out of or based upon, such right of subrogation until the principal of, premium,
if any, and interest on all the Notes shall have been paid in full and until all
amounts payable under any Senior Indebtedness shall have been paid in full.

      SECTION 17.2 AGREEMENT OF SUBORDINATION. The Guarantor covenants and
agrees, and each holder of Notes issued hereunder by its acceptance thereof
likewise covenants and agrees, that all Notes are subject to the provisions of
this Article XVII; and each Person holding any Note, whether upon original issue
or upon transfer, assignment or exchange thereof, accepts and agrees to be bound
by such provisions.

      The payment of the principal of, premium, if any, and interest (including
Liquidated Damages, if any) on all Notes (including, but not limited to, the
redemption price with respect to the Notes called for redemption in accordance
with Section 3.2 or submitted for redemption in accordance with Section 3.5, as
the case may be, as provided in the Indenture) issued hereunder shall, to the
extent and in the manner hereinafter set forth, be subordinated and subject in
right of payment to the prior payment in full of all Guarantor Senior
Indebtedness, whether outstanding at the date of this Indenture or thereafter
incurred.

      No provision of this Article XVII shall prevent the occurrence of any
default or Event of Default hereunder.

      SECTION 17.3 PAYMENTS TO NOTEHOLDERS. No payment shall be made with
respect to the principal of, premium, if any, or interest (including Liquidated
Damages, if any) on the Notes


                                      -10-
<PAGE>   12
(including, but not limited to, the redemption price with respect to the Notes
to be called for redemption in accordance with Section 3.2 or submitted for
redemption in accordance with Section 3.5, as the case may be, as provided in
this Indenture), except payments and distributions made by the Trustee as
permitted by the first or second paragraph of Section 17.6, if:

                  (i) a default in the payment of principal, premium, if any,
interest, rent or other obligations in respect of Guarantor Senior Indebtedness
occurs and is continuing (or, in the case of Guarantor Senior Indebtedness for
which there is a period of grace, in the event of such a default that continues
beyond the period of grace, if any, specified in the instrument or lease
evidencing such Senior Indebtedness) (a "Payment Default"), unless and until
such Payment Default shall have been cured or waived or shall have ceased to
exist; or

                  (ii) a default, other than a Payment Default, on any
Designated Guarantor Senior Indebtedness occurs and is continuing that then
permits holders of such Designated Guarantor Senior Indebtedness to accelerate
its maturity and the Trustee receives a notice of the default (a "Payment
Blockage Notice") from a holder of Designated Guarantor Senior Indebtedness, a
Representative of Designated Guarantor Senior Indebtedness or the Guarantor (a
"Non-Payment Default").

      If the Trustee receives any Payment Blockage Notice pursuant to clause
(ii) above, no subsequent Payment Blockage Notice shall be effective for
purposes of this Section 17.3 unless and until (A) at least 365 days shall have
elapsed since the initial effectiveness of the immediately prior Payment
Blockage Notice and (B) all scheduled payments of principal, premium, if any,
and interest (including Liquidated Damages, if any) on the Notes that have come
due have been paid in full in cash. No Non-Payment Default that existed or was
continuing on the date of delivery of any Payment Blockage Notice to the Trustee
shall be, or be made, the basis for a subsequent Payment Blockage Notice.

      The Guarantor may and shall resume payments on and distributions in
respect of the Notes upon the earlier of:


      (1)   the date upon which any such Payment Default is cured or waived or
            ceases to exist, or

      (2)   in the case of a Non-Payment Default, the earlier of (a) the date
            upon which such default is cured or waived or ceases to exist or (b)
            179 days after notice is received if the maturity of such Designated
            Guarantor Senior Indebtedness has not been accelerated,

unless this Article XVII otherwise prohibits the payment or distribution at the
time of such payment or distribution.

      Upon any payment by the Guarantor, or distribution of assets of the
Guarantor of any kind or character, whether in cash, property or securities, to
creditors upon any dissolution or winding up or


                                      -11-
<PAGE>   13
liquidation or reorganization of the Guarantor, whether voluntary or involuntary
or in bankruptcy, insolvency, receivership or other proceedings, all amounts due
or to become due upon all Guarantor Senior Indebtedness shall first be paid in
full in cash or other payment satisfactory to the holders of such Guarantor
Senior Indebtedness, or payment thereof in accordance with its terms provided
for in cash or other payment satisfactory to the holders of such Guarantor
Senior Indebtedness before any payment is made on account of the principal of,
premium, if any, or interest (including Liquidated Damages, if any) on the Notes
(except payments made pursuant to Article XIII from monies deposited with the
Trustee pursuant thereto prior to commencement of proceedings for such
dissolution, winding up, liquidation or reorganization); and upon any such
dissolution or winding up or liquidation or reorganization of the Guarantor or
bankruptcy, insolvency, receivership or other proceeding, any payment by the
Guarantor, or distribution of assets of the Guarantor of any kind or character,
whether in cash, property or securities, to which the holders of the Notes or
the Trustee would be entitled, except for the provision of this Article XVII,
shall (except as aforesaid) be paid by the Guarantor or by any receiver, trustee
in bankruptcy, liquidating trustee, agent or other Person making such payment or
distribution, or by the holders of the Notes or by the Trustee under this
Indenture if received by them or it, directly to the holders of Guarantor Senior
Indebtedness (pro rata to such holders on the basis of the respective amounts of
Guarantor Senior Indebtedness held by such holders, or as otherwise required by
law or a court order) or their representative or representatives, or to the
trustee or trustees under any indenture pursuant to which any instruments
evidencing any Guarantor Senior Indebtedness may have been issued, as their
respective interests may appear, to the extent necessary to pay all Guarantor
Senior Indebtedness in full, in cash or other payment satisfactory to the
holders of such Guarantor Senior Indebtedness, after giving effect to any
concurrent payment or distribution to or for the holders of Guarantor Senior
Indebtedness, before any payment or distribution is made to the holders of the
Notes or to the Trustee.

      For purposes of this Article XVII, the words, "cash, property or
securities" shall not be deemed to include shares of stock of the Guarantor as
reorganized or readjusted, or securities of the Guarantor or any other
corporation provided for by a plan of reorganization or readjustment, the
payment of which is subordinated at least to the extent provided in this Article
XVII with respect to the Notes to the payment of all Guarantor Senior
Indebtedness which may at the time be outstanding; provided that (i) the
Guarantor Senior Indebtedness is assumed by the new corporation, if any,
resulting from any reorganization or readjustment, and (ii) the rights of the
holders of Guarantor Senior Indebtedness (other than leases which are not
assumed by the Guarantor or the new corporation, as the case may be) are not,
without the consent of such holders, altered by such reorganization or
readjustment. The consolidation of the Guarantor with, or the merger of the
Guarantor into, another corporation or the liquidation or dissolution of the
Guarantor following the conveyance or transfer of its property as an entirety,
or substantially as an entirety, to another corporation upon the terms and
conditions provided for in Article XII shall not be deemed a dissolution.
winding-up, liquidation or reorganization for the purposes of this Section 17.3
if such other corporation shall, as a part of such consolidation, merger,
conveyance or transfer, comply with the conditions stated in Article XII.

      In the event of the acceleration of the Notes because of an Event of
Default, no payment or distribution shall be made to the Trustee or any holder
of Notes in respect of the principal of, premium, if any, or interest (including
Liquidated Damages, if any) on the Notes (including, but not


                                      -12-
<PAGE>   14
limited to, the redemption price with respect to the Notes called for redemption
in accordance with Section 3.2 or submitted for redemption in accordance with
Section 3.5, as the case may be, as provided in the Indenture), except payments
and distributions made by the Trustee as permitted by the first or second
paragraph of Section 17.6, until all Guarantor Senior Indebtedness has been paid
in full in cash or other payment satisfactory to the holders of Guarantor Senior
Indebtedness or such acceleration is rescinded in accordance with the terms of
this Indenture. If payment of the Notes is accelerated because of an Event of
Default, the Guarantor shall promptly notify holders of Guarantor Senior
Indebtedness of the acceleration.

      In the event that, notwithstanding the foregoing provisions, any payment
or distribution of assets of the Guarantor of any kind or character, whether in
cash, property or securities (including, without limitation, by way of setoff or
otherwise), prohibited by the foregoing provisions in this Section 17.3, shall
be received by the Trustee or the holders of the Notes before all Guarantor
Senior Indebtedness is paid in full in cash or other payment satisfactory to the
holders of such Guarantor Senior Indebtedness, or provision is made for such
payment thereof in accordance with its terms in cash or other payment
satisfactory to the holders of such Guarantor Senior Indebtedness, such payment
or distribution shall be held in trust for the benefit of and shall be paid over
or delivered to the holders of Guarantor Senior Indebtedness or their
representative or representatives, or to the trustee or trustees under any
indenture pursuant to which any instruments evidencing any Guarantor Senior
Indebtedness may have been issued, as their respective interests may appear, as
calculated by the Guarantor, for application to the payment of any Guarantor
Senior Indebtedness remaining unpaid to the extent necessary to pay all
Guarantor Senior Indebtedness in full in cash or other payment satisfactory to
the holders of such Guarantor Senior Indebtedness, after giving effect to any
concurrent payment or distribution to or for the holders of such Guarantor
Senior Indebtedness.

      Nothing in this Section 17.3 shall apply to claims of, or payments to, the
Trustee under or pursuant to Section 8.6. This Section 17.3 shall be subject to
the further provisions of Section 17.6.

      SECTION 17.4 SUBROGATION OF NOTES. Subject to the payment in full of all
Guarantor Senior Indebtedness, the rights of the holders of the Notes shall be
subrogated to the extent of the payments or distributions made to the holders of
such Guarantor Senior Indebtedness pursuant to the provisions of this Article
XVII (equally and ratably with the holders of all indebtedness of the Guarantor
which by its express terms is subordinated to other indebtedness of the
Guarantor to substantially the same extent as the Notes are subordinated and is
entitled to like rights of subrogation) to the rights of the holders of
Guarantor Senior Indebtedness to receive payments or distributions of cash,
property or securities of the Guarantor applicable to the Guarantor Senior
Indebtedness until the principal, premium, if any, and interest (including
Liquidated Damages, if any) on the Notes shall be paid in full; and, for the
purposes of such subrogation, no payments or distributions to the holders of the
Guarantor Senior Indebtedness of any cash, property or securities to which the
holders of the Notes or the Trustee would be entitled except for the provisions
of this Article XVII, and no payment over pursuant to the provisions of this
Article XVII, to or for the benefit of the holders of Guarantor Senior
Indebtedness by holders of the Notes or the Trustee, shall, as between the
Guarantor, its creditors other than holders of Guarantor Senior Indebtedness,
and the holders of the Notes, be deemed to be a payment by the Guarantor to or
on account of the Guarantor Senior Indebtedness; and no payments or
distributions of cash, property or securities to or for the


                                      -13-
<PAGE>   15
benefit of the holders of the Notes pursuant to the subrogation provisions of
this Article XVII, which would otherwise have been paid to the holders of
Guarantor Senior Indebtedness shall be deemed to be a payment by the Guarantor
to or for the account of the Notes. It is understood that the provisions of this
Article XVII are and are intended solely for the purposes of defining the
relative rights of the holders of the Notes, on the one hand, and the holders of
the Guarantor Senior Indebtedness, on the other hand.

      Nothing contained in this Article XVII or elsewhere in this Indenture or
in the Notes is intended to or shall impair, as among the Guarantor, its
creditors other than the holders of Guarantor Senior Indebtedness, and the
holders of the Notes, the obligation of the Guarantor, which is absolute and
unconditional, to pay to the holders of the Notes the principal of, premium, if
any, and interest (including Liquidated Damages, if any) on the Notes as and
when the same shall become due and payable in accordance with their terms, or is
intended to or shall affect the relative rights of the holders of the Notes and
creditors of the Guarantor other than the holders of the Guarantor Senior
Indebtedness, nor shall anything herein or therein prevent the Trustee or the
holder of any Note from exercising all remedies otherwise permitted by
applicable law upon default under this Indenture, subject to the rights, if any,
under this Article XVII of the holders of Guarantor Senior Indebtedness in
respect of cash, property or securities of the Guarantor received upon the
exercise of any such remedy.

      Upon any payment or distribution of assets of the Guarantor referred to in
this Article XVII, the Trustee, subject to the provisions of Section 8.1, and
the holders of the Notes shall be entitled to rely upon any order or decree made
by any court of competent jurisdiction in which such bankruptcy, dissolution,
winding up, liquidation or reorganization proceedings are pending, or a
certificate of the receiver, trustee in bankruptcy, liquidating trustee, agent
or other person making such payment or distribution, delivered to the Trustee or
to the holders of the Notes, for the purpose of ascertaining the persons
entitled to participate in such distribution, the holders of the Guarantor
Senior Indebtedness and other indebtedness of the Guarantor, the amount thereof
or payable thereon and all other facts pertinent thereto or to this Article
XVII.

      SECTION 17.5 AUTHORIZATION TO EFFECT SUBORDINATION. Each holder of a Note
by the holder's acceptance thereof authorizes and directs the Trustee on the
holder's behalf to take such action as may be necessary or appropriate to
effectuate the subordination as provided in this Article XVII and appoints the
Trustee to act as the holder's attorney-in-fact for any and all such purposes.
If the Trustee does not file a proper proof of claim or proof of debt in the
form required in any proceeding referred to in the third paragraph of Section
7.2 hereof at least thirty (30) days before the expiration of the time to file
such claim, the holders of any Guarantor Senior Indebtedness or their
representatives are hereby authorized to file an appropriate claim for and on
behalf of the holders of the Notes.

      SECTION 17.6 NOTICE TO TRUSTEE. The Guarantor shall give prompt written
notice in the form of an Officers' Certificate to a Responsible Officer of the
Trustee and to any paying agent of any fact known to the Guarantor which would
prohibit the making of any payment of monies to or by the Trustee or any paying
agent in respect of the Notes pursuant to the provisions of this Article XVII.
Notwithstanding the provisions of this Article XVII or any other provision of
this Indenture,


                                      -14-
<PAGE>   16
the Trustee shall not be charged with knowledge of the existence of any facts
which would prohibit the making of any payment of monies to or by the Trustee in
respect of the Notes pursuant to the provisions of this Article XVII, unless and
until a Responsible Officer of the Trustee shall have received written notice
thereof at the Corporate Trust Office from the Guarantor (in the form of an
Officers' Certificate) or a Representative or a holder or holders of Guarantor
Senior Indebtedness or from any trustee thereof; and before the receipt of any
such written notice, the Trustee, subject to the provisions of Section 8.1,
shall be entitled in all respects to assume that no such facts exist; provided
that if on a date not less than two Business Days prior to the date upon which
by the terms hereof any such monies may become payable for any purpose
(including, without limitation, the payment of the principal of, or premium, if
any, or interest (including Liquidated Damages, if any) on any Note) the Trustee
shall not have received, with respect to such monies, the notice provided for in
this Section 17.6, then, anything herein contained to the contrary
notwithstanding, the Trustee shall have full power and authority to apply moneys
received to the purpose for which they were received, and shall not be affected
by any notice to the contrary which may be received by it on or after such prior
date.

      Notwithstanding anything in this Article XVII to the contrary, nothing
shall prevent any payment by the Trustee to the Noteholders of monies deposited
with it pursuant to Section 13.1, and any such payment shall not be subject to
the provisions of Section 17.2 or 17.3.

      The Trustee, subject to the provisions of Section 8.1, shall be entitled
to rely on the delivery to it of a written notice by a Representative or a
person representing himself to be a holder of Guarantor Senior Indebtedness (or
a trustee on behalf of such holder) to establish that such notice has been given
by a Representative or a holder of Guarantor Senior Indebtedness or a trustee on
behalf of any such holder or holders. The Trustee shall not be required to make
any payment or distribution to or on behalf of a holder of Guarantor Senior
Indebtedness pursuant to this Article XVII unless it has received satisfactory
evidence as to the amount of Guarantor Senior Indebtedness held by such person,
the extent to which such person is entitled to participate in such payment or
distribution and any other facts pertinent to the rights of such person under
this Article XVII.

      SECTION 17.7 TRUSTEE'S RELATION TO GUARANTOR SENIOR INDEBTEDNESS. The
Trustee in its individual capacity shall be entitled to all the rights set forth
in this Article XVII in respect of any Guarantor Senior Indebtedness at any time
held by it, to the same extent as any other holder of Guarantor Senior
Indebtedness, and nothing in Section 8.13 or elsewhere in this Indenture shall
deprive the Trustee of any of its rights as such holder.

      With respect to the holders of Guarantor Senior Indebtedness, the Trustee
undertakes to perform or to observe only such of its covenants and obligations
as are specifically set forth in this Article XVII, and no implied covenants or
obligations with respect to the holders of Guarantor Senior Indebtedness shall
be read into this Indenture against the Trustee. The Trustee shall not be deemed
to owe any fiduciary duty to the holders of Guarantor Senior Indebtedness and,
subject to the provisions of Section 8.1, the Trustee shall not be liable to any
holder of Guarantor Senior Indebtedness (i) for any failure to make any payments
or distributions to such holder or (ii) if it shall pay over or deliver to
holders of Notes, the Guarantor or any other person money or assets to which any
holder of Guarantor Senior Indebtedness shall be entitled by virtue of this
Article XVII or otherwise.


                                      -15-
<PAGE>   17
      SECTION 17.8 NO IMPAIRMENT OF SUBORDINATION. No right of any present or
future holder of any Guarantor Senior Indebtedness to enforce subordination as
herein provided shall at any time in an way be prejudiced or impaired by any act
or failure to act on the part of the Guarantor or by any act or failure to act,
in good faith, by any such holder, or by any noncompliance by the Guarantor with
the terms, provisions and covenants of this Indenture, regardless of any
knowledge thereof which any such holder may have or otherwise be charged with.

      SECTION 17.9 CERTAIN CONVERSIONS NOT DEEMED PAYMENT. For the purposes of
this Article XVII only, (1) the issuance and delivery of junior securities upon
conversion of Notes in accordance with Article XV shall not be deemed to
constitute a payment or distribution on account of the principal of, premium, if
any, or interest (including Liquidated Damages, if any) on Notes or on account
of the purchase or other acquisition of Notes, and (2) the payment, issuance or
delivery of cash (except in satisfaction of fractional shares pursuant to
Section 15.3), property or securities (other than junior securities) upon
conversion of a Note shall be deemed to constitute payment on account of the
principal of, premium, if any, or interest (including Liquidated Damages, if
any) on such Note. For the purposes of this Section 17.9, the term "junior
securities" means (a) shares of any stock of any class of the Guarantor or (b)
securities of the Guarantor that are subordinated in right of payment to all
Guarantor Senior Indebtedness that may be outstanding at the time of issuance or
delivery of such securities to substantially the same extent as, or to a greater
extent than, the Notes are so subordinated as provided in this Article. Nothing
contained in this Article XVII or elsewhere in this Indenture or in the Notes is
intended to or shall impair, as among the Guarantor, its creditors (other than
holders of Guarantor Senior Indebtedness) and the Noteholders, the right, which
is absolute and unconditional, of the Holder of any Note to convert such Note in
accordance with Article XV.

      SECTION 17.10 ARTICLE APPLICABLE TO PAYING AGENTS. If at any time any
paying agent other than the Trustee shall have been appointed by the Guarantor
and be then acting hereunder, the term "Trustee" as used in this Article shall
(unless the context otherwise requires) be construed as extending to and
including such paying agent within its meaning as fully for all intents and
purposes as if such paying agent were named in this Article in addition to or in
place of the Trustee; provided, however, that the first paragraph of Section
17.6 shall not apply to the Guarantor or any Affiliate of the Guarantor if it or
such Affiliate acts as paying agent.

      The Trustee shall not be responsible for the actions or inactions of any
other paying agents (including the Guarantor if acting as its own paying agent)
and shall have no control of any funds held by such other paying agents.

      SECTION 17.11 GUARANTOR SENIOR INDEBTEDNESS ENTITLED TO RELY. The holders
of Guarantor Senior Indebtedness (including, without limitation, Designated
Guarantor Senior Indebtedness) shall have the right to rely upon this Article
XVII, and no amendment or modification of the provisions contained herein shall
diminish the rights of such holders unless such holders shall have agreed in
writing thereto.

      SECTION 17.12    RELIANCE ON JUDICIAL ORDER OR CERTIFICATE OF
LIQUIDATING AGENT.  Upon any payment or distribution of assets of the
Guarantor referred to in this Article, the Trustee and the


                                      -16-
<PAGE>   18
Noteholders shall be entitled to rely upon any order or decree entered by any
court of competent jurisdiction in which such insolvency, bankruptcy,
receivership, liquidation, reorganization, dissolution, winding up or similar
case or proceeding is pending, or a certificate of the trustee in bankruptcy,
liquidating trustee, custodian, receiver, assignee for the benefit of creditors,
agent or other person making such payment or distribution, delivered to the
Trustee or to the Noteholders, for the purpose of ascertaining the persons
entitled to participate in such payment or distribution, the holders of
Guarantor Senior Indebtedness and other indebtedness of the Guarantor, the
amount thereof or payable thereon, the amount or amounts paid or distributed
thereon and all other facts pertinent thereto or to this Article.

                                   ARTICLE V

                    IMMUNITY OF INCORPORATORS, STOCKHOLDERS,

                             OFFICERS AND DIRECTORS

      SECTION 5.1 IMMUNITY OF INCORPORATORS, STOCKHOLDERS, OFFICERS AND
DIRECTORS. Article XIV of the Indenture is hereby amended by deleting in
entirety Article Fourteen and inserting in lieu thereof the following Article
XIV: 

                                  ARTICLE XIV

                   IMMUNITY OF INCORPORATORS, STOCKHOLDERS,

                             OFFICERS AND DIRECTORS

      SECTION 14.1 INDENTURE AND NOTES SOLELY CORPORATE OBLIGATIONS. No recourse
for the payment of the principal of or premium, if any, or interest on any Note,
or for any claim based thereon or otherwise in respect thereof, and no recourse
under or upon any obligation, covenant or agreement of the Company or the
Guarantor in this Indenture or in any supplemental indenture, or in any Note, or
because of the creation of any indebtedness represented thereby or the guarantee
by the Guarantor thereof, shall be had against any incorporator, stockholder,
employee, agent, officer or director or subsidiary, as such, past, present or
future, of the Company or the Guarantor or of any respective successor
corporation, either directly or through the Company or the Guarantor or any
respective successor corporation, whether by virtue of any constitution, statute
or rule of law, or by the enforcement of any assessment or penalty or otherwise;
it being expressly understood that all such liability is hereby expressly waived
and released as a condition of, and as a consideration for, the execution of
this Indenture and the issue of the Notes; provided, however, that the foregoing
shall not affect or impair the obligations of the Guarantor hereunder.


                                      -17-
<PAGE>   19
                                   ARTICLE VI

                            MISCELLANEOUS PROVISIONS

      SECTION 6.1 This First Supplemental Indenture shall become effective at
the Effective Time and shall be automatically null and void if and in the event
that the Merger shall not become effective on or prior to April 16, 1999.

      SECTION 6.2 This First Supplemental Indenture shall be governed by and
construed in accordance with the laws of the State of New York, without regard
to the principles of conflicts of laws thereof.

      SECTION 6.3 Except as expressly contemplated by Sections 1.2(d) and 5.1
hereof, nothing in this First Supplemental Indenture, expressed or implied,
shall give or be construed to give any person, firm or corporation, other than
the parties hereto and their successors hereunder, and the holders of the Notes
or the holders of Guarantor Senior Indebtedness, any legal or equitable right,
remedy or claim under or in respect to this First Supplemental Indenture, or
under any covenant, condition or provision herein contained; all such covenants,
conditions and provisions being for the sole benefit of the parties hereto and
their successors hereunder and the holders of the Notes.

      SECTION 6.4 The Trustee accepts the amendment of the Indenture effected by
this First Supplemental Indenture and agrees to execute the trust created by the
Indenture as hereby amended, but only upon the terms and conditions set forth in
the Indenture, including the terms and provisions defining and limiting the
liabilities and responsibilities of the Trustee, which terms and provisions
shall in like manner define and limit its liabilities and responsibilities in
the performance of the trust created by the Indenture as hereby amended.

      SECTION 6.5 After the Effective Time, any Notes authenticated and
delivered in substitution for, or in lieu of, Notes then outstanding and all
Notes presented or delivered to the Trustee on and after the Effective Time for
such purpose shall be either restated to give the effect to the First
Supplemental Indenture or, in lieu thereof, stamped with a notation
substantially as follows:

                  The principal amount of this Note has become convertible into
            shares of the Common Stock, without par value per share, of
            SpeedFam-Ipec, Inc., at an initial Conversion Price per share of
            $54.93, such Conversion Price being subject to certain adjustments
            as set forth in the Indenture. Reference herein to "Common Stock of
            the Company" or the "Company's Common Stock" shall be deemed to be
            to the Common Stock of SpeedFam-Ipec, Inc. The payment of principal
            of, premium, if any, and interest on the Notes has been guaranteed
            by SpeedFam-Ipec, Inc. on a subordinated basis as set forth in the
            Indenture. The Indenture, dated as of September 15, 1997, referred
            to in this Note has been amended by a First Supplemental Indenture,
            dated as of April 6, 1999, to provide for such convertibility and
            guarantee. Reference is hereby made to said First


                                      -18-
<PAGE>   20
            Supplemental Indenture, copies of which are on file with Integrated
            Process Equipment Corp. and SpeedFam-Ipec, Inc., for a statement of
            the amendment therein made.

      Nothing contained in this First Supplemental Indenture shall require the
holder of any Note to submit or exchange such Note prior to the Effective Time
in order to obtain the benefits of the Guaranty or any other provisions
hereunder.

      The Company agrees to provide the Trustee with a stamp or means of
reproducing the above legend on the Notes without materially obscuring the text
of the Notes.

      Anything herein contained to the contrary notwithstanding, the Trustee
shall not at any time be under any responsibility to acquire or cause any Note
now or hereafter outstanding to be presented or delivered to it for any purpose
provided for in this Section 6.5.

      SECTION 6.6 Except as expressly supplemented by this First Supplemental
Indenture, the Indenture, the Notes issued thereunder and the charge and
obligation created thereby are in all respects ratified and confirmed and all of
the rights, remedies, terms, conditions, covenants and agreements of the
Indenture and the Notes issued thereunder shall remain in full force and effect.

      SECTION 6.7 If any provision of this First Supplemental Indenture limits,
qualifies or conflicts with (a) another provision of this First Supplemental
Indenture, or (b) any provision of the Indenture, which is required to be
included by any of the provisions of Section 310 to 317, inclusive, of the Trust
Indenture Act, such required provision shall control.

      SECTION 6.8 The recitals contained in this First Supplemental Indenture
shall be taken as statements of the Company or the Guarantor, as applicable, and
the Trustee assumes no responsibility for their correctness. The Trustee makes
no representations as to the validity or sufficiency of this First Supplemental
Indenture.

      SECTION 6.9 This First Supplemental Indenture may be executed in any
number of counterparts, each of which shall be an original; but such
counterparts shall together constitute but one and the same instrument.


                                      -19-
<PAGE>   21
      IN WITNESS WHEREOF, the parties hereto have caused this First Supplemental
Indenture to be duly executed, and their respective corporate seals to be
hereunto affixed and attested, all as of the day and year first above written.

                                          INTEGRATED PROCESS EQUIPMENT CORP.


                                          By:    /s/ John S. Hodgson
                                                --------------------------------
                                          Name:  John S. Hodgson
                                                --------------------------------
                                          Title: Vice President and CFO
                                                --------------------------------

                                          SPEEDFAM-IPEC, INC.


                                          By:    /s/ Richard J. Faubert
                                                --------------------------------
                                          Name:  Richard J. Faubert
                                                --------------------------------
                                          Title: President and CEO
                                                --------------------------------

                                          STATE STREET BANK AND TRUST COMPANY
                                          OF CALIFORNIA, N.A.,
                                          as Trustee


                                          By:    /s/ Scott C. Emmons
                                                --------------------------------
                                          Name:  Scott C. Emmons
                                                --------------------------------
                                          Title: Assistant Vice President
                                                --------------------------------


                                      -20-