Document:

<PAGE>

                                   Exhibit A
                                   ---------

                         Interest Terms and Provisions

                                      -38-
<PAGE>
                                                                    Exhibit 10.5

                                    EXHIBIT A

     This Exhibit A provides for certain of the substantive terms and provisions
regarding, among other things, the interest rate, interest repayment, and
selection and conversion of optional interest rates for the Loan established
pursuant to the Loan Agreement to which this document is attached as an Exhibit
(the "Loan Agreement"). The terms and provisions of this Exhibit A are
specifically incorporated by reference into the Loan Agreement.

1.   The following terms as used in this Exhibit A and the Loan Agreement shall
     have the meanings set forth below:

     Base Rate.  The higher of (a) the annual rate of interest announced from
time to time by the Lender at its head office in Boston, Massachusetts as its
"base rate" and (b) one half of one percent ( 1/2%) above the overnight federal
funds effective rate as published by the Board of Governors of the Federal
Reserve System, as in effect from time to time.

     Business Day.  Any day on which the Lender is open for the transaction of
banking business in Boston, Massachusetts and, in case of LIBOR Rate Loans, also
a day which is a LIBOR Business Day.

     Conversion Request.  A notice given by the Borrower to the Lender of (i)
its initial selection of an interest rate option for an Advance in accordance
with Paragraph 5, herein,  or (ii) its election to convert or continue an
interest rate option for a Loan in accordance with Paragraph 6, herein.

     Convert, Conversion and Converted. The conversion of a Loan from one Type
to Loans of another Type.

     Domestic Rate. For any Interest Period with respect to each Domestic Rate
Loan, floating at the per annum rate equal to the Base Rate.  The Domestic Rate
shall be adjusted automatically on any change in the Base Rate, such that any
change in the Domestic Rate resulting therefrom shall become effective as of the
opening of business on the day on which such change in the Base Rate became
effective.

     Domestic Rate Loan. All or any portion of any Advance or the Loan which
bears interest at the Domestic Rate.

       Eurocurrency Reserve Rate.  For any day with respect to a LIBOR Rate
Loan, the maximum rate (expressed as a decimal) at which any lender subject
thereto would be required to maintain reserves under Regulation D of the Board
of Governors of the Federal Reserve System (or any successor or similar
regulations relating to such reserve requirements) against "Eurocurrency
Liabilities" (as that term is used in Regulation D), if such

                                       1
<PAGE>

liabilities were outstanding. The Eurocurrency Reserve Rate shall be adjusted
automatically on and as of the effective date of any change in the Eurocurrency
Reserve Rate.

     Fixed Rate.  For any Interest Period with respect to a Fixed Rate Loan, an
interest rate per annum equal at all times during such Interest Period to the
sum of (i) One and Three-Eighths percent (1.375%) and (ii) the Lender's cost of
funds (as determined by the Lender) for a period equal to the Interest Period
(plus any internal incremental increase, as determined and established by the
Lender's treasury department, as a cost of the availability of such funds).

     Fixed Rate Loan. All or any portion of an Advance or the Loan bearing
interest at the Fixed Rate.

     Interest Payment Date.  (a) As to any Loan, the first day of each calendar
month commencing with the calendar month following the calendar month which
includes the date of the Advance of such Loan; and (b) as to any LIBOR Rate
Loan, the last day of each Interest Period.

     Interest Period.  With respect to each Loan, (a) initially, the period
commencing on the date of the Advance of such Loan and ending on the last day of
one of the periods set forth below (i) for any Domestic Rate Loan, the last day
of the calendar month; (ii) as selected by the Borrower in a Conversion Request,
for any LIBOR Rate Loan, 1, 2, 3, or 6 months; and (iii) for any Fixed Rate
Loan, the then applicable Maturity Date, and (b) thereafter, for any Domestic
Rate Loan or LIBOR Rate Loan, each period commencing on the last day of the next
preceding Interest Period applicable to such Loan and ending on the last day of
one of the periods set forth above, as selected by the Borrower in a Conversion
Request; provided that all of the foregoing provisions relating to Interest
Periods are subject to the following:

          (A) if any Interest Period with respect to a LIBOR Rate Loan would
     otherwise end on a day that is not a LIBOR Business Day, that Interest
     Period shall be extended to the next succeeding LIBOR Business Day unless
     the result of such extension would be to carry such Interest Period into
     another calendar month, in which event such Interest Period shall end on
     the immediately preceding LIBOR Business Day;

          (B) if any Interest Period with respect to a Domestic Rate Loan would
     end on a day that is not a Business Day, that Interest Period shall end on
     the next succeeding Business Day;

          (C) if the Borrower shall fail to give notice as provided in Paragraph
     6, herein, the Borrower shall be deemed to have requested a conversion of
     the affected LIBOR

                                       2
<PAGE>

     Rate Loan to a Domestic Rate Loan on the last day of the then current
     Interest Period with respect thereto;

          (D) any Interest Period relating to any LIBOR Rate Loan that begins on
     the last LIBOR Business Day of a calendar month (or on a day for which
     there is no numeri  cally corresponding day in the calendar month at the
     end of such Interest Period) shall end on the last LIBOR Business Day of a
     calendar month; and

          (E) any Interest Period relating to any LIBOR Rate Loan that would
     otherwise extend beyond the Maturity Date shall end on the Maturity Date.

     LIBO Rate.  For any Interest Period with respect to a LIBOR Rate Loan, the
interest rate per annum (rounded upwards to the next highest 1/16 of 1%)
determined by the Lender pursuant to the following formula:

          Euro Rate  =   LIBO Bid Rate
                         -------------
                         1.00 - Eurocurrency Reserve Rate

     LIBO Bid Rate.  For any Interest Period with respect to a LIBOR Rate Loan,
the annual rate of interest determined by the Lender on the second Business Day
prior to the first day of such Interest Period to be the rate at which deposits
in U.S. dollars are offered to the Lender by prime banks in whatever Eurodollar
interbank market may be selected by the Lender in its sole discretion, acting in
good faith, at the time of determination and in accordance with the usual
practice in such market for delivery on the first day of such Interest Period
for the number of days comprised therein and in an amount equal (as nearly as
may be) to the principal amount of such LIBOR Rate Loan.

     LIBOR Business Day.  Any day on which commercial banks are open for
international business (including dealings in Dollar deposits) in London or such
other eurodollar interbank market as may be selected by the Lender in its sole
discretion acting in good faith.

     LIBOR Rate.  For any Interest Period with respect to a LIBOR Rate Loan, an
interest rate per annum equal at all times during such Interest Period to the
(i) LIBO Rate plus (ii) One and Three-Eighths percent (1.375%).

     LIBOR Rate Loan.  All or any portion of an Advance or the Loan bearing
interest calculated by reference to the LIBOR Rate.

     Type of Loan. A Domestic Rate Loan or a LIBOR Rate Loan, as the case may
be.

                                       3
<PAGE>

2.   Any and all terms which are defined in the Loan Agreement shall when used
     herein have the meaning set forth in the Loan Agreement, unless otherwise
     defined herein.

3.   The Loan shall bear interest as follows:

     1.   For each Interest Period:

          i.   To the extent that all or any portion of the Loan is a Domestic
               Rate Loan, such portion shall bear interest during such Interest
               Period at the floating rate equal to the Domestic Rate.

          ii.  To the extent that all or any portion of the Loan is a LIBOR Rate
               Loan, such portion shall bear interest during such Interest
               Period at the LIBOR Rate determined for such Interest Period.

          iii  To the extent that all or any portion of the Loan is a Fixed Rate
               Loan, such portion shall bear interest during such Interest
               Period at the Fixed Rate determined for such Interest Period.

4.   The Borrower promises to pay interest on the Loan in arrears on each
     Interest Payment Date applicable to such Interest Period.

5.   The Borrower agrees that each request submitted to the Lender requesting an
     Advance shall be accompanied by a written notice of Borrower (the
     "Conversion Request") specifying (i) the requested Type of Loan comprising
     such Advance, (ii) in the case of an Advance comprised of any LIBOR Rate
     Loan, the initial Interest Period; and (iii) the amount of each Type of
     Loan; provided, however, that each LIBOR Rate Loan and Fixed Rate Loan
     shall be in an amount of $100,000.00 or integral multiple thereof. A
     Conversion Request with respect to a LIBOR Rate Loan or a Fixed Rate Loan
     shall be irrevocable and binding on Borrower.  If no Conversion Request is
     given by Borrower to the Lender with respect to any request for an Advance,
     the Borrower shall be deemed to have selected a Domestic Rate Loan.

6.   Upon notice given by Borrower to the Lender not later than 12:00 noon
     (Boston time) in the case of Conversions into LIBOR Rate Loans or a Fixed
     Rate Loan, on the third Business Day prior to the date of the proposed
     Conversion, the Borrower may Convert, on any Business Day, Loans of one
     Type made to the Borrower into Loans of another Type, provided, however,
     that (a) any Conversion of LIBOR Rate Loans may be made only on the last
     day of the respective Interest Period for such Loans, (b) any Loan
     Converted to a LIBOR Rate Loan shall be in an amount of at least
     $100,000.00 or integral

                                       4
<PAGE>

     multiple thereof, (c) any Loan Converted to a Fixed Rate Loan shall be in
     an amount of the outstanding principal balance of the Note, (d) a Fixed
     Rate Loan shall not be Converted by the Borrower to a Loan of any other
     Type, (e) any Loan Converted to a Fixed Rate Loan shall be for the balance
     of the then applicable term of the Loan, and (f) no Advance may be
     Converted to a LIBOR Rate Loan or a Fixed Rate Loan when any Default or
     Event of Default has occurred and is continuing. Each such Conversion
     Request shall be by telephone, telecopy, telex or cable, in each case
     confirmed immediately in writing in the manner specified for notices
     herein, and shall, within the restrictions specified above, specify (i) the
     date of such Conversion, (ii) the Loans to be Converted, and (iii) if such
     Conversion is to LIBOR Rate Loan the duration of the initial Interest
     Period for such Loans. Each Conversion Request with respect to LIBOR Rate
     Loans or a Fixed Rate Loan shall be irrevocable and binding on the
     Borrower. Notwithstanding anything stated herein, the Borrower may not
     submit a Converstion Request to Convert any Loan into a Domestic Rate Loan.
     The Domestic Rate shall only be applicable if the LIBOR Rate or the Fixed
     Rate is not available, or except as otherwise provided herein.

7.   If after giving a Conversion Request, the Borrower fails to borrow or
     Convert any LIBOR Rate Loan or any Fixed Rate Loan, the Borrower shall
     indemnify the Lender against any loss or expense incurred by the Lender as
     a result of such failure including, without limitation, any loss or expense
     incurred by reason of the liquidation or reemployment of deposits or other
     funds acquired by the Lender to fund or maintain an Advance to be made by
     the Lender and the compensation as provided for in Paragraph 13, herein.

8.   Any Loans of any Type (other than a Fixed Rate Loan) may be continued as
     such upon the expiration of an Interest Period with respect thereto by
     compliance by the Borrower with the notice provisions contained in
     Paragraph 6, above; provided that no LIBOR Rate Loan may be continued as
     such when any Default or Event of Default has occurred and is continuing,
     but shall be automatically converted to a Domestic Rate Loan on the last
     day of the first Interest Period relating thereto ending during the
     continuance of any Default or Event of Default of which the officers of the
     Lender active upon the Borrower's account have actual knowledge.

9.   In the event that the Borrower does not notify the Lender of its election
     under Paragraph 6, herein, in a timely manner with respect to any Loan upon
     the expiration of the applicable Interest Period, such Loan shall be
     automatically converted to a Domestic Rate Loan at the end of the
     applicable Interest Period.

                                       5
<PAGE>

10.  Upon the expiration of any Interest Period for a Fixed Rate Loan, such Loan
     shall be automatically converted to a Domestic Rate Loan.

11.  Notwithstanding anything to the contrary contained herein, in no event may
     the Borrower select more than three (3) Interest Periods to be in effect at
     any one time for any particular Type of Loan.

12.  Each determination of an interest rate by the Lender pursuant hereto shall
     be conclusive and binding upon the Borrower in the absence of manifest
     error.

13.  The Borrower agrees to indemnify the Lender and to hold the Lender harmless
     from and against any loss, cost or expense (including loss of anticipated
     profits) that the Lender may sustain or incur as a consequence of (a) an
     Event of Default by the Borrower in payment of the principal amount of or
     any interest on any LIBOR Rate Loans or Fixed Rate Loans as and when due
     and payable, including any such loss or expense arising from interest or
     fees payable by the Lender to lenders of funds obtained by it in order to
     maintain its LIBOR Rate Loans or Fixed Rate Loans, (b) an Event of Default
     by the Borrower in making a borrowing or conversion after the Borrower has
     given (or is deemed to have given) a Conversion Request, or (c) the making
     of any payment of any LIBOR Rate Loan or Fixed Rate Loan or the making of
     any conversion of any such Loan to a Domestic Rate Loan on a day that is
     not the last day of the applicable Interest Period with respect thereto,
     whether due to voluntary prepayment, payment realized from the Collateral
     or any Guarantor after the occurrence of an Event of Default, or otherwise,
     including interest or fees payable by the Lender to lenders of funds
     obtained by it in order to maintain any such Loans. Such loss shall
     include, without limitation, an amount calculated as follows:

     1.   First, the Lender shall determine the amount by which (i) the total
          amount of interest which would have otherwise accrued hereunder on
          each installment of principal so paid or not borrowed, during the
          period beginning on the date of such payment or failure to borrow and
          ending on the date such installment would have been due (the
          "Reemployment Period"), exceeds (ii) the total amount of interest
          which would accrue, during the Reemployment Period, on any readily
          marketable bond or other obligation of the United States of America
          designated by the Lender in its sole discretion at or about the time
          of such payment, such bond or other obligation of the United States of
          America to be in an amount equal (as nearly as may be) to the amount
          of principal so paid or not borrowed and to have a

                                       6
<PAGE>

          maturity comparable to the Reemployment Period, and the interest to
          accrue thereon to take account of amortization of any discount from
          par or accretion of premium above par at which the same is selling at
          the time of designation. Each sum amount is hereafter referred to as
          an "Installment Amount".

     2.   Second, each Installment Amount shall be treated as payable as of the
          date on which the related principal installment would have been
          payable by the Borrower had such principal installment not been
          prepaid or not borrowed.

     3.   Third, the amount to be paid on each such date shall be the present
          value of the Installment Amount determined by discounting the amount
          thereof from the date on which such Installment Amount is to be
          treated as payable, at the same annual interest rate as that payable
          upon the bond or other obligation of the United States of America
          designated as aforesaid by the Lender.

14.  In the event, prior to the commencement of any Interest Period relating to
     any LIBOR Rate Loan, the Lender shall determine that adequate and
     reasonable methods do not exist for ascertaining the LIBO Rate that would
     otherwise determine the rate of interest to be applicable to any LIBOR Rate
     Loan during any Interest Period, the Lender shall forthwith give notice of
     such determination (which shall be conclusive and binding on the Borrower)
     to the Borrower.  In such event (a) any Conversion Request with respect to
     LIBOR Rate Loans shall be automatically withdrawn and shall be deemed a
     request for Domestic Rate Loans, (b) each LIBOR Rate Loan will
     automatically, on the last day of the then current Interest Period thereof,
     become a Domestic Rate Loan, and (c) the obligations of the Lender to make
     LIBOR Rate Loans shall be suspended until the Lender determines that the
     circumstances giving rise to such suspension no longer exist, whereupon the
     Lender shall so notify the Borrower.

15.  Notwithstanding any other provisions herein, if any present or future law,
     regulation, treaty or directive or in the interpretation or application
     thereof shall make it unlawful for the Lender to make or maintain LIBOR
     Rate Loans, the Lender shall forthwith give notice of such circumstances to
     the Borrower and thereupon (a) the commitment of the Lender to make LIBOR
     Rate Loans or convert Loans of another type to LIBOR Rate Loans shall
     forthwith be suspended and (b) the LIBOR Rate Loans then outstanding shall
     be converted auto  matically to Domestic Rate Loans on the last day of each
     Interest Period applicable to such LIBOR Rate Loans or

                                       7
<PAGE>

     within such earlier period as may be required by law. The Borrower hereby
     agrees promptly to pay the Lender, upon demand, any additional amounts
     necessary to compensate the Lender for any costs incurred by the Lender in
     making any conversion in accordance with this section, including any
     interest or fees payable by the Lender to lenders of funds obtained by it
     in order to make or maintain its LIBOR Rate Loans hereunder and any amount
     payable as provided in Paragraph 13, herein.

16.  The Borrower shall have the right at any time to prepay the Note on or
     before the Maturity Date, as a whole, or in part, subject to the following
     limitations:

     1.   For any Domestic Rate Loan, without premium or penalty, provided that
          any amount prepaid shall be accompanied by accrued interest on the
          principal repaid to the date of payment;

     2.   For any LIBOR Rate Loan, upon not less than three (3) Business Days'
          prior written notice to the Lender, without penalty, provided that (1)
          each partial prepayment shall be in the principal amount of
          $100,000.00 or an integral multiple thereof, (2) if such prepayment is
          on any day other than the last day of the Interest Period relating
          thereto, such amount prepaid shall be accompanied by any additional
          amounts necessary to compensate the Lender for any costs incurred by
          the Lender in accordance with Paragraph 13, herein, including any
          interest or fees payable by the Lender to lenders of funds obtained by
          it in order to make or maintain its LIBOR Rate Loans hereunder and (3)
          any amount prepaid shall be accompanied by accrued interest on the
          principal repaid to the date of payment.

     3.   For any Fixed Rate Loan upon not less than thirty (30) Business Days'
          prior written notice to the Lender, without penalty, provided that
          such amount prepaid shall be accompanied by any additional amount
          equal to the amounts necessary to compensate the Lender for any costs
          incurred by the Lender in accordance with Paragraph 13, herein,
          including any interest or fees payable by the Lender to lenders of
          funds obtained by it in order to make or maintain its Fixed Rate Loans
          hereunder and any amount prepaid shall be accompanied by accrued
          interest on the principal repaid to the date of payment.

     4.   If the Loan Documents provide at the time of prepayment for periodic
          principal payments on the Loan, any prepayment of principal shall be
          applied against the

                                       8
<PAGE>

          scheduled installments of principal due on the Loan in the inverse
          order of maturity. No amount repaid with respect to the Loan may be
          reborrowed.

     5.   In the event that at the time of any such prepayment Loans are
          outstanding of more than one Type, the amount prepaid shall be applied
          first to any Domestic Rate Loan prior to application to any LIBOR Rate
          Loans or Fixed Rate Loans.

     6.   Any premium due hereunder upon such prepayment shall be due and
          payable upon any prepayment whatsoever, whether voluntary or
          involuntary, to the extent permitted by law, and after acceleration of
          the unpaid principal balance of the Loan after the occurrence of an
          Event of Default.

17.  All computations of interest on the Loans and of other fees to the extent
     applicable shall be based on a 360-day year and paid for the actual number
     of days elapsed.  Except as otherwise provided in the definition of the
     term "Interest Period" with respect to LIBOR Rate Loans, whenever a payment
     hereunder or under any of the other Loan Documents becomes due on a day
     that is not a Business Day, the due date for such payment shall be extended
     to the next succeeding Business Day, and interest shall accrue during such
     extension.

                                       9<PAGE>

         FIRST AMENDMENT TO UNSECURED COMMITTED REVOLVER LOAN AGREEMENT

      This FIRST AMENDMENT TO UNSECURED COMMITTED REVOLVER LOAN AGREEMENT is
dated as of March 6, 2000 by and between:

      CITIZENS BANK OF MASSACHUSETTS (as successor in interest to State Street
Bank and Trust Company), with an address of 28 State Street, Boston,
Massachusetts 02109 (hereinafter, the "BANK"); and

      APPLIED SCIENCE AND TECHNOLOGY, INC., a Delaware corporation, with a
principal place of business at 35 Cabot Road, Woburn, Massachusetts 01801
(hereinafter, the "BORROWER").

                                   BACKGROUND

      WHEREAS, the Borrower and the Bank entered into a certain loan arrangement
(hereinafter, the "LOAN ARRANGEMENT") evidenced by, among other documents,
instruments, and agreements, a certain Unsecured Committed Revolver Loan
Agreement dated as of May 1, 1997 (hereinafter, the "REVOLVER AGREEMENT") and a
certain Unsecured Committed Revolver Promissory Note dated as of May 1, 1997
(hereinafter, the "NOTE") in the original principal amount of $8,000,000.00 made
payable by the Borrower to the order of the Bank; and

      WHEREAS, the Borrower has requested and the Bank has agreed to restructure
the terms and provisions of the Loan Arrangement, including, without limitation,
(i) an extension of the Expiration (as defined in the Revolver Agreement) from
May 31, 2000 through April 1, 2003; (ii) a change in the interest rate options
available to the Borrower from the Prime Rate (as defined in the Revolver
Agreement) and the Market Rate (as defined in the Revolver Agreement) to the
Domestic Rate (as defined hereunder) and the LIBOR Rate (as defined hereunder)
and (iii) a change in the applicable financial covenants, as set forth herein;

      Accordingly, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, it is hereby agreed by and among
the Bank and the Borrower as follows:

      1.    All references to the "Note" in the Revolver Agreement shall mean
            the Note, as amended by that certain First Amendment to Unsecured
            Committed Revolver Promissory Note dated March 6, 2000.

      2.    The term "Loans" as set forth in Section 1.0 of Article I of the
            Revolver Agreement is hereby deleted in its entirety and replaced
            with the following:
<PAGE>

            " "Loans" shall mean Domestic Rate Loans, LIBOR Rate Loans and
            Standby Letters of Credit issued by the Bank from time to time
            hereunder".

      3.    The terms "Domestic Rate Loan" and "LIBOR Rate Loan" shall have the
            meanings ascribed to such terms within Exhibit A, attached to and
            made a part hereof. All other terms so defined within Exhibit A are
            hereby incorporated by reference.

      4.    The terms "Market Rate", "Market Rate Loan", "Prime Rate", and
            "Prime Rate Loan" as set forth in the Revolver Agreement are hereby
            deleted in their entirety.

      5.    The last sentence of Section 2.1 of Article II of the Revolver
            Agreement is hereby deleted in its entirety and replaced with the
            following:

            " The principal amount of the Revolver shall be payable upon the
            earlier of either (a) the expiration of this Agreement on April 1,
            2003 (the "Expiration") or (b) upon the occurrence of an Event of
            Default (subject to and as provided herein)."

      6.    Section 2.2 and 2.5 of Article II of the Revolver Agreement and
            Subsections (1), and (2) of Section 2.3 of Article II of the
            Revolver Agreement are hereby deleted in their entirety. All terms
            and conditions relating to the advances of Loans under the Revolver
            Agreement, the applicable rate of interest accruing on outstanding
            loans, and the repayment of such Loans shall be governed by the
            terms and provisions set forth within Exhibit A, attached hereto and
            made a part hereof.

      7.    Subsection (4) of Section 2.3 of Article II of the Revolver
            Agreement is hereby deleted in its entirety and replaced with the
            following:

            "Default Rate. Any principal amount not paid immediately upon
            acceleration by reason of an Event of Default shall bear interest
            thereafter, until paid, at a rate equal to the aggregate of the
            Domestic Rate plus four (4%) percent per annum (the "Default
            Rate")."

      8.    Section 3.0 of Article III of the Revolver Agreement is hereby
            deleted in its entirety and replaced with the following:

                                     - 2 -
<PAGE>

            "The proceeds of the Loans hereunder shall be used only for the
            purpose of supporting acquisition financing, letters of credit, and
            working capital requirements."

      9.    The date of the consolidated balance sheet set forth in Section 5.4
            of Article V of the Revolver Agreement shall be changed from "June
            29, 1996" to "June 26, 1999" and the date of the Borrower's Form
            10-K shall be changed from "1996" to "1999".

      10.   The date of the Borrower's Form 10-K set forth in Article V, Section
            5.7 of the Revolver shall be changed from "1996" to "1999".

      11.   All references to the "Acquisition Transaction" shall hereby be
            deleted in the entirety.

      12.   Section 8.0 of Article VIII of the Revolver is hereby deleted in its
            entirety and replaced with the following:

            "So long as the Note shall remain unpaid or the Bank shall have any
            commitment under this Agreement:

            1.    The Borrower will maintain Minimum Working Capital of not less
                  than $18,000,000.00 at the end of each of Borrower's fiscal
                  quarter.

            2.    The Borrower will maintain at all times a Maximum Debt to
                  Tangible Net Worth ratio of no more than: 1.50:1 from and
                  after December 31, 1999.

            3.    As of March 31, 1999, the Borrower will maintain a Tangible
                  Net Worth of not less than $30,000,000.00. Thereafter, the
                  Borrower's Tangible Net Worth will increase (as of the end of
                  each of the Borrower's quarters) by a minimum of an aggregate
                  of 40% of the prior quarter's Net Income.

            4.    The Borrower will maintain Minimum Debt Service Coverage
                  defined as the ratio of aggregate Net Income of the Borrower
                  plus aggregate depreciation, plus aggregate amortization, less
                  aggregate Capital Expenditures not financed on a

                                     - 3 -
<PAGE>

                  long-term basis to Current Maturities of Long Term Debt of the
                  Borrower of 1.75:1. This covenant shall be tested on a rolling
                  quarterly basis for a four fiscal quarter period.

            5.    The Borrower will not suffer a negative Net Income for two
                  fiscal quarters during any fiscal year.

                  All of the foregoing covenants shall be tested as of the last
                  day o f each of the Borrower's fiscal quarters commencing with
                  the Borrower's fiscal quarter first ending on March __, 2000.

                  Capitalized terms otherwise not defined herein shall be
            defined in accordance with GAAP."

      13.   Subsection (5) of Section 9.0 of Article IX of the Revolver
            Agreement is hereby deleted in its entirety and replaced with the
            following:

            "There exists any Event of Default as defined under that certain
            loan arrangement by and between ASTeX Realty Corp. and the Bank
            evidenced by, among other documents, instruments and agreements,
            that certain Loan Agreement dated as of March 6, 2000, and that
            certain Note dated as of March 6, 2000 in the original principal
            amount of $10,000,000.00."

      14.   Section 11.1 of Article XI of the Revolver Agreement is hereby
            deleted in its entirety and replaced with the following:

            "Each notice, demand, election or request provided for or permitted
            to be given pursuant to this Agreement or any other Loan Document
            (hereinafter in this Section referred to as "Notice") must be in
            writing and shall be deemed to have been properly given or served by
            personal delivery or by sending same by overnight courier or by
            depositing same in the United States Mail, postpaid and registered
            or certified, return receipt requested, and addressed as follows:

            If to the Bank;

                  Citizens Bank of Massachusetts
                  28 State Street
                  Boston, Massachusetts 02109
                  Attn: Ms. Suzanne Dwyer, Vice President

                                     - 4 -
<PAGE>

            With a copy to:

                  Riemer & Braunstein LLP
                  Three Center Plaza
                  Boston, Massachusetts 02108
                  Attn: Jonathan D. Yellin, Esquire

            If to the Borrower:

                  Applied Science and Technology, Inc.
                  35 Cabot Road
                  Woburn, Massachusetts 01801
                  Attn: William S. Hurley, Senior Vice President and
                        Chief Financial Officer

            With a copy to:

                  Mintz Levin Cohn Ferris Glovsky & Popeo, PC
                  1 Financial Center
                  Boston, Massachusetts 02111
                  Attn: Stephen T. Langer, Esquire

            Each Notice shall be effective upon being personally delivered or
            upon being sent by overnight courier or upon being deposited in the
            United States Mail as aforesaid. The time period in which a response
            to such Notice must be given or any action taken with respect
            thereto (if any), however, shall commence to run from the date of
            receipt if personally delivered or sent by overnight courier, or if
            so deposited in the United States Mail, the earlier of three (3)
            Business Days following such deposit or the date of receipt as
            disclosed on the return receipt. Rejection or other refusal to
            accept or the inability to deliver because of changed address for
            which no Notice was given shall be deemed to be receipt of the
            Notice sent. By giving at least thirty (30) days' prior Notice
            thereof, the Borrower or the Bank shall have the right from time to
            time and at any time during the term of this Agreement to change
            their respective addresses and each shall have the right to specify
            as its address any other address within the United States of
            America."

      15.   The Borrower hereby ratifies, confirms, and reaffirms all of the
            terms and conditions of the Revolver Agreement, and all of the other
            documents, instruments, and agreements evidencing the Loan
            Arrangement including, without limitation, the Note. In addition,
            the Borrower acknowledges and agrees that the Bank is not agreeing
            by this First Amendment to Unsecured Committed Revolver Loan
            Agreement to amend, modify, or alter any of the terms and conditions
            of the Loan Arrangement except to the extent provided herein.

      16.   Any determination that any provision of this First Amendment to
            Unsecured Committed Revolver Loan Agreement or any application
            hereof is invalid, illegal or unenforceable in any respect and in
            any instance

                                     - 5 -
<PAGE>

            shall not effect the validity, legality, or enforceability of such
            provision in any other instance, or the validity, legality or
            enforceability of any other provisions of this First Amendment to
            Unsecured Committed Revolver Loan Agreement.

      17.   The Borrower shall pay on demand all costs and expenses of the Bank,
            including, without limitation, reasonable attorneys' fees in
            connection with the preparation, negotiation, execution and delivery
            of this First Amendment to Unsecured Committed Revolver Loan
            Agreement.

      18.   The Borrower warrants and represents that the Borrower has consulted
            with independent legal counsel of the Borrower's selection in
            connection with this First Amendment to Unsecured Committed Revolver
            Loan Agreement and is not relying on any representations or
            warranties of the Bank or its counsel in entering into this First
            Amendment to Unsecured Committed Revolver Loan Agreement.

      19.   The Borrower acknowledges, confirms and agrees that it has no
            offsets, defenses, claims or counterclaims against the Bank with
            respect to any of the Borrower's liabilities and obligations to the
            Bank under the Loan Arrangement, and to the extent that the Borrower
            has any such claims under the Loan Arrangement, the Borrower
            affirmatively WAIVES and RENOUNCES such claims as of the date
            hereof.

                                     - 6 -
<PAGE>

      IN WITNESS WHEREOF, this First Amendment to Unsecured Committed Revolver
Loan Agreement has been executed as a sealed instrument as of the date first set
forth above.

WITNESS:                                  BORROWER

/s/ C. L. Glynn                           APPLIED SCIENCE AND TECHNOLOGY, INC.
------------------
                                          By:  /s/ William S. Hurley
                                              ---------------------------------
                                          Name: William S. Hurley
                                          Title: Senior Vice President and
                                                 Chief Financial Officer

Acknowledged and Agreed to:
CITIZENS BANK OF MASSACHUSETTS

By:    /s/ Suzanne L. Dwyer
    ---------------------------------
Name:  Suzanne L. Dwyer
      -------------------------------
Title: Vice President
       ------------------------------

                                     - 7 -

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00008-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00008-of-00352.parquet"}]]