<PAGE>   1
                                                                   EXHIBIT 10.42

                            REAL ESTATE MORTGAGE NOTE

$5,600,000.00                                              Boston, Massachusetts
                                                           June 30,1997

         FOR VALUE RECEIVED, the undersigned, BTU International, Inc., a
Delaware corporation, having a mailing address of 23 Esquire Road, Billerica,
Massachusetts 01862 (the "Maker"), promises to pay to the order of JOHN HANCOCK
MUTUAL LIFE INSURANCE COMPANY, a Massachusetts corporation, having a mailing
address at John Hancock Place, Post Office Box 111, Boston, Massachusetts 02117
(the payee and each successor holder of this Note being herein called the
"Holder".) or to such other person or at such other place as the Holder may from
time to time designate in writing, the principal sum of Five Million Six Hundred
Thousand & 00/100 Dollars ($5,600,000.00), with interest from the date hereof
payable in arrears (except as provided in Paragraph 1 (a) below) on so much
thereof as shall from time to time be outstanding at an annual rate of eight and
125/100 Percent (8.125%) per annum (the "Fixed Rate").

1.       Payment of Principal and Interest. Principal and interest evidenced by
         this Note shall be paid as follows:

         (a)      If the date of disbursement of the loan (the "Funding Date")
                  does not fall on the first day of a month, there shall be paid
                  on the Funding Date, for the period commencing on the Funding
                  Date and ending on and including the last day of the month in
                  which the Funding Date has occurred, interest only on the
                  principal balance outstanding on the Funding Date at the Fixed
                  Rate.

         (b)      Commencing on August 1,1997, and continuing on the first day
                  of each of the next successive eighty-three (83) months, there
                  shall be paid to the Holder the sum of and Fifty-three
                  Thousand Nine Hundred Twenty-one & 41/100 Dollars
                  ($53,921.41), which shall first be applied to any payment
                  owing to Holder as a result of an event of default or late
                  charges hereunder or under any other instrument securing this
                  Note, next to interest at the Fixed Rate set forth above, and
                  any remainder to principal or applied in such other order as
                  the Holder may determine in its sole and absolute discretion.

         (c)      The entire unpaid principal balance, accrued and unpaid
                  interest thereon and all other sums due shall in any event be
                  due and payable on July 1, 2004 (the "Maturity Date").

2.       Default and Acceleration. At the option of the Holder, the entire
         indebtedness evidenced by this Note shall become immediately due and
         payable without notice or demand upon the occurrence at any time of any
         of the following events of default (a) failure to pay in full any
         installment of principal or interest when due, or default of the Maker,
         or any endorser or guarantor hereof, under any liability, obligation or
         undertaking, hereunder or otherwise, to the Holder; (b) an Event of
         Default as defined in the Mortgage and Security Agreement of even date
         and


                                       1
<PAGE>   2
         delivery herewith (the "Mortgage") shall occur; (c) any default or
         breach in the covenants, conditions or agreements of any other
         instrument securing this Note or otherwise delivered in connection with
         the Loan shall occur; (d) any statement, representation or warranty
         made in or in connection with the application for the loan evidenced by
         this Note, in the Mortgage, in any supporting financial statement or in
         any other instrument securing the loan of the Maker, any endorser or
         guarantor hereof, or any signatory to any other instrument securing
         this Note or otherwise delivered in connection with the loan shall
         prove to have been false, misleading or erroneous in any material
         respect when made; (e) the liquidation, winding-up, termination of
         existence or dissolution of the organization of the Maker, any endorser
         or guarantor hereof, or any signatory to any other instrument securing
         this Note or otherwise delivered in connection with the loan, or the
         cessation of the business activities as presently conducted by the
         Maker, any endorser or guarantor hereof, or any signatory to any other
         instrument securing this Note or otherwise delivered in connection with
         the loan; (f) the Maker, any endorser or guarantor hereof, or any
         signatory to any other instrument securing this Note or otherwise
         delivered in connection with the loan grants a trust mortgage, or
         executes a general assignment for the benefit of creditors, or fails
         generally to pay its debts as they mature, or petitions or applies for
         the appointment of a liquidator or a receiver of the Maker, any
         endorser or guarantor hereof or any signatory to any other instrument
         securing this Note, or otherwise delivered in connection with the loan,
         or of any substantial part of the assets of the Maker, any endorser or
         guarantor hereof, or any signatory to any other instrument securing
         this Note or otherwise delivered in connection with the loan, or
         commences any proceeding under any bankruptcy, reorganization,
         insolvency, readjustment of debt, dissolution or liquidation law or
         similar law of any jurisdiction, now or hereafter in effect, or any
         order for relief shall be entered in any such proceeding, or the Maker,
         any endorser or guarantor hereof, or any signatory to any other
         instrument securing this Note or otherwise delivered in connection with
         the loan, shall acquiesce to the entry of an order for relief in any
         such proceeding; (g) the filing of any petition or application
         commencing any proceeding against the Maker, any endorser or guarantor
         hereof, or any signatory to any other instrument securing this Note or
         otherwise delivered in connection with the loan, under any bankruptcy,
         reorganization, insolvency, readjustment of debt, dissolution or
         liquidation law or similar law of any jurisdiction now or hereafter in
         effect, where such petition or application is not dismissed within
         thirty (30) days after the date such petition or application was filed
         or where such proceeding is not dismissed or stayed within thirty (30)
         days after the date such proceeding was commenced; (h) the death or
         adjudicated incompetence of any of the Maker (or any beneficiary of the
         Maker), of any endorser or guarantor hereof, or of a signatory to any
         other instrument securing this Note or otherwise delivered in
         connection with the loan, and if any of the Maker, its beneficiary, or
         any such signatory, endorser or guarantor is a partnership, the death
         or adjudicated incompetence of any partner; or (i) failure of the Maker
         to prepay the outstanding


                                       2
<PAGE>   3
         indebtedness hereunder after giving the Holder notice of its intent to
         prepay pursuant to the provisions of Paragraph 4 hereof.

         The Maker acknowledges that the loan evidenced by this Note was made on
         the basis and assumption that the Holder would receive regular payments
         of principal and interest set forth in Paragraph 1 of this Note from
         the Funding Date to and including the Maturity Date. Therefore, if at
         any time the entire indebtedness becomes due and payable following an
         event of default hereunder, then, to the extent permitted by law, the
         Holder hereof shall be entitled, in addition to the outstanding
         principal balance, accrued interest and other sums due under this Note
         or any other instrument securing the loan, to be paid a premium (the
         "Default Premium") as of the date the indebtedness becomes due and
         payable. The Default Premium shall be an amount equal to the greater
         of:

         (i)      ten percent (10%) of the principal amount becoming due because
                  of such event of default and acceleration; or

         (ii)     the sum obtained by multiplying (x) the principal amount
                  becoming due because of such acceleration, (y) the number of
                  years and fraction thereof remaining between such acceleration
                  date and the Maturity Date, and (z) an annual rate of interest
                  equal to the difference obtained by subtracting the yield rate
                  on publicly traded United States Treasury Securities due on or
                  closest to the Maturity Date (as such yield rate is reported
                  in The Wall Street Journal or other similar business
                  publications of general circulation on the fifth day preceding
                  such acceleration date) from the Fixed Rate adjusted to its
                  semiannual equivalent rate of 8.2638%. Notwithstanding the
                  foregoing, if such an event of default occurs on or after the
                  date on which the prepayment is permitted, as set forth in
                  Paragraph 4 below, the Default Premium shall be equal to the
                  amount calculated according to clause (iii) of said Paragraph
                  4.

                  In the event that the yield rate on publicly traded United
                  States Treasury Securities is not obtainable, then the nearest
                  equivalent issue or index shall be selected, in the Holder's
                  reasonable determination, and used to calculate the Default
                  Premium.

                  A tender of the amount necessary to satisfy the entire
                  indebtedness evidenced by this Note, paid at any time
                  following an event of default and acceleration, including at a
                  foreclosure sale, shall be deemed a voluntary prepayment and,
                  at the Holder's option, such payment shall include the Default
                  Premium. Upon the occurrence of an event of default hereunder,
                  the Holder may apply, at the Holder's election, any payments
                  made by the Maker to amounts due under this Note or under any
                  other instrument securing this Note or delivered in connection
                  with the loan evidenced by this Note.

3.       Interest Payable Upon Default. Upon the occurrence of an event of
         default hereunder or after the Maturity Date, the Fixed Rate stated
         above shall be


                                       3
<PAGE>   4
         increased by an additional seven percent (7%) per annum, but in no
         event more than the maximum rate allowed by law. Said increased rate of
         interest shall remain in effect for such time as the default continues,
         provided that any additional interest that has accrued shall be paid at
         the time of, and as a condition precedent to, the curing of any
         default.

         The Maker agrees to pay all costs of collection, including reasonable
         fees and expenses of the Holder's attorneys, upon any default in the
         payment of principal or interest when due, and all costs, including
         reasonable fees and expenses of the Holder's attorneys, in case it
         becomes necessary to protect the security hereof, whether or not suit
         is commenced.

4.       Prepayment The indebtedness evidenced hereby may not be prepaid in
         whole or in part before August 1, 2001.

         Thereafter, the Note may be prepaid in whole, but not in part, provided
         that (a) an event of default has not occurred hereunder; (b) the Maker
         gives the Holder no less than thirty (30) days (nor more than ninety
         (90 days) prior written notice of its intent to prepay, which notice
         specifies the exact date of prepayment (the "Prepayment Date"); and (c)
         the Maker pays the following on the Prepayment Date:

         (i)      the outstanding principal balance;

         (ii)     accrued interest;

         (iii)    a prepayment premium equal to the greater of one percent (1%)
                  of the then outstanding principal balance or the sum obtained
                  by multiplying (x) the then outstanding principal balance, (y)
                  the number of years and fraction thereof remaining between the
                  Prepayment Date and the Maturity Date, and (z) an annual rate
                  of interest equal to the difference obtained by subtracting
                  the yield rate on publicly traded United States Treasury
                  Securities due on or about the Maturity Date (as such yield
                  rate is reported in The Wall Street Journal or other similar
                  business publications of general circulation on the fifth day
                  preceding such Prepayment Date) from the Fixed Rate adjusted
                  to its semiannual equivalent rate of 8.2638%; provided,
                  however, in the event that the yield rate on publicly traded
                  United States Treasury Securities is not obtainable, then the
                  nearest equivalent issue or index shall be selected, in the
                  Holder's reasonable determination, and used to calculate the
                  foregoing prepayment premium; and

         (iv)     other sums due under this Note or any other instrument
                  securing the loan.

         Notwithstanding the foregoing, this Note may be prepaid in whole, but
         not in part, without premium, during the period commencing ninety (90)
         days prior to the Maturity Date, through the Maturity Date, provided
         that (a) an event of default has not occurred hereunder; (b) the Maker
         gives the Holder not less than thirty (30)


                                       4
<PAGE>   5
         days, nor more than sixty (60) days, prior written notice of its intent
         to prepay, which notice specifies the Prepayment Date; and (c) the
         Maker pays on the Prepayment Date the outstanding principal balance,
         accrued interest and other sums due under this Note or any other
         instrument securing the loan.

         No partial prepayment shall be allowed.

5.       Usury Laws. In the event the payments required to be made hereunder or
         pursuant to the Mortgage, whether such payments are characterized as
         interest or otherwise, shall at any time exceed the limits permitted by
         any law governing usury or any other law applicable to the loan
         evidenced hereby, all such excess sums paid by the Maker for the period
         in question shall, without further agreement or notice between or by
         any party hereto, be applied to the principal balance as a prepayment
         thereof without premium, or at Holder's option, returned to Maker.

6.       Waivers by Maker. The Maker hereof, and all endorsers and guarantors of
         this Note, hereby severally waive presentment for payment, protest and
         demand, notice of protest, demand and of dishonor and nonpayment of
         this Note, and the Maker's (and any endorser's or guarantor's)
         liability hereunder shall remain unimpaired, notwithstanding any
         extension of the time of payment or other indulgence granted by the
         Holder hereof, or the release of all or any part of the security for
         the payment hereof or the liability of any party which may assume the
         obligation to make payment of the indebtedness evidenced hereby or the
         performance of the obligations of the Maker. The obligations of the
         Maker and any endorsers and guarantors hereof shall be joint and
         several.

7.       Notices. Whenever notice, demand or a request under this Note may
         properly be given to the Maker or the Holder, the same shall be in
         writing and shall be (a) hand delivered to the party intended to
         receive the same or (b) sent by registered or certified mail, postage
         prepaid, return receipt requested, with a reference in either case to
         Loan No.6516959 GB, addressed to the Maker or the Holder at the address
         given in this Note, or to such other address as either party shall
         furnish to the other by like notice, and any such notice, demand or
         request shall be treated as having been given when so delivered, or if
         mailed, when deposited with the U.S. Postal Service.

8.       Compliance with Regulation G. The Maker agrees that no part of the
         proceeds of this Note shall be used for the purpose, whether immediate,
         incidental or ultimate, of "purchasing" or "carrying". any "margin
         stock", as such terms are defined in Regulation G (12 C.F.R. Part 207)
         of the Board of Governors of the Federal Reserve System, or for the
         purpose of reducing or retiring any indebtedness which was originally
         incurred for any such purpose.

9.       Security for Note. This Note is secured by the Mortgage, which is to be
         recorded with the Middlesex South District Registry of Deeds and to be
         filed for registration


                                       5
<PAGE>   6
         with the Middlesex South Registry District of the Land Court, and by
         certain other instruments securing the Note or otherwise delivered in
         connection with the loan evidenced by this Note. The Mortgage
         constitutes an encumbrance on certain property, more particularly
         described therein, located on Esquire Road, Billerica, Middlesex
         County, Massachusetts.

10.      Headings. The descriptive headings of the paragraphs of this Note are
         inserted for convenience only and do not constitute a part of this
         Note.

         This Note has been negotiated and is being delivered in and shall be
         governed by and construed in accordance with the laws of the
         Commonwealth of Massachusetts, to the maximum extent the parties may so
         lawfully agree.

         EXECUTED AS A SEALED INSTRUMENT, as of the day and year first above
         written.

In the presence of                       MAKER:



BTU International, Inc.

--------------------------------------------------------------------------------
Thomas P. Kealy
Its Vice President


                                       6
<PAGE>   7
                         MORTGAGE AND SECURITY AGREEMENT

         BTU International, Inc., a Delaware corporation, having a mailing
address of 23 Esquire Road, Billerica, Massachusetts 01862 ("Mortgagor"), for
consideration paid, GRANTS to John Hancock Mutual Life Insurance Company, a
Massachusetts corporation, having a mailing address at John Hancock Place, Post
Office Box 111, Boston, Massachusetts 02117 ("Mortgagee"), with MORTGAGE
COVENANTS, to secure payment of Five Million Six Hundred and 00/100 Dollars
($5,600,000.00), with interest thereon on such part thereof as shall from time
to time remain unpaid (the "Loan"), all payable as provided in that certain note
of even date herewith from Mortgagor to Mortgagee (the "Note"), and also to
secure the performance of all agreements contained herein, in the Note, in the
application/commitment for the Loan dated February 27, 1997 and accepted by
Mortgagee on March 19, 1997, as amended, (the "Commitment") and in all other
instruments securing the Note or otherwise delivered in connection with the Loan
(collectively, together with the Note, the Commitment and this Mortgage and
Security Agreement, the "Loan Documents") and the payment and performance of all
other debts and obligations of any nature, direct or indirect, absolute or
contingent, now or hereafter owed by Mortgagor to Mortgagee, the following:

         The registered and unregistered land located on Esquire Road,
Billerica, Middlesex County, Massachusetts, as more particularly described in
Exhibit A attached hereto, and all easements, rights, and appurtenances
belonging or pertaining thereto (the "Land"), and the buildings, structures and
other improvements now or hereafter constructed thereon (the "Improvements")
(the Land and the Improvements are collectively referred to herein as the "Real
Property"); and

         Together with all internal operating systems which are physically
incorporated into the Real Property and which are necessary for the operation
and maintenance of the Real Property, including, without limitation, heating,
lighting, plumbing, lifting, sprinkling and ventilating apparatus, air-cooling
and airconditioning apparatus, elevators and escalators and the like, all
materials intended for construction, reconstruction, alteration and repair of
the Real Property and any replacements thereof or additions thereto
(collectively, together with the Real Property, the "Mortgaged Property"), and
all rents, income, profits, condemnation awards, refunds or abatements of
Impositions (as defined in Paragraph 7), casualty insurance proceeds, general
intangibles or contract rights arising from or relating to the Mortgaged
Property, warranties and guaranties of construction contractors or
subcontractors or of suppliers or manufacturers of equipment or other property
incorporated into the Improvements or otherwise constituting part of the
Mortgaged Property, licenses and permits for the operation of the Mortgaged
Property, and books and records of Mortgagor relating to construction, use,
operation and occupancy of the Real Property (collectively, together with the
Mortgaged Property, the "Security"). The Security shall not include any personal
property of Mortgagor, nor any equipment, machinery or other fixtures used by
Mortgagor in connection with its business or located on any land owned by
Mortgagor not described on Exhibit A.


                                       1
<PAGE>   8
         Mortgagor, as debtor, hereby grants to Mortgagee, as secured party, a
first priority security interest in the above-described fixtures and agrees that
Mortgagee shall have with respect thereto (in addition to all other rights and
remedies hereunder), all rights and remedies of a secured party under the
Massachusetts Uniform Commercial Code ("Uniform Commercial Code"). This
instrument is intended to be effective as a financing statement filed as a
fixture filing under the Uniform Commercial Code.

         Certain of the goods described herein are or are to become fixtures
related to the Real Property. The record owner of the Land is Mortgagor.
Mortgagor covenants and agrees with Mortgagee that:

         1. Mortgagor's Interest in Security. Mortgagor is lawfully seized in
fee simple of the Security, and has good right, full power and lawful authority
to sell and convey the same in the manner aforesaid, the Security is free and
clear of all encumbrances except as otherwise provided in Exhibit B attached
hereto, and Mortgagor shall correct such defects of title and make any further
assurances of title that Mortgagee may require.

         2. Performance of Obligations. Mortgagor will pay the Note and interest
thereon and any other indebtedness owed by Mortgagor to Mortgagee, all as the
same become due and payable, and will comply with and perform all of the
covenants and agreements of Mortgagor in the Loan Documents.

         3. Maintenance: Compliance with laws: etc. Mortgagor will at all times
maintain the Mortgaged Property in good order, condition and repair; make all
repairs, replacements, improvements and additions which may be necessary to
preserve and maintain the Mortgaged Property; permit Mortgagee, its agents and
representatives to inspect the Mortgaged Property at any reasonable time,
including, without limitation, for the purpose of inspecting the soil and
groundwater by sampling, monitoring or other methods of detection of Hazardous
Materials (as hereinafter defined) and for the purpose of inspecting any
construction on the Mortgaged Property; comply with all requirements made by
Mortgagee with respect to maintaining and preserving the Mortgaged Property;
comply with all laws, ordinances, orders, rules and regulations of all
governmental authorities and insurance underwriters with respect to the
Mortgaged Property and any business conducted thereon and any construction or
alteration undertaken thereon; not violate or permit the violation of any
covenants or agreements affecting the Mortgaged Property; not alter, destroy or
remove any of the Mortgaged Property or commit or suffer any waste or permit the
Mortgaged Property to be altered, destroyed or removed or used for any purpose
other than that for which it is now used or for the Proposed Uses (as
hereinafter defined) without first obtaining Mortgagee's written permission
(except that Mortgagor may, in the ordinary course of its business, replace
articles of personal property with other articles of like value and utility);
not file a declaration of condominium, map or other document having the effect
of subjecting the Security to the cooperative or condominium form of ownership;
not acquire any fixtures or equipment subject to any security interest,
conditional sale, title retention arrangement or other charge or lien taking
precedence over the encumbrance hereof; complete in a good workmanlike manner
any building or improvement which is being or may hereafter be constructed or
repaired thereon; pay when due all claims for labor


                                       2
<PAGE>   9
performed and material furnished and not permit any notice of contract or lien
of mechanics or materialmen to attach to the Mortgaged Property; and maintain
and preserve all rights and privileges now or hereafter held by it which are
necessary or useful in connection with the Mortgaged Property. Mortgagor will
use the Mortgaged Property solely as an owner-occupant and for research,
development and manufacturing uses (the "Proposed Uses"). Any rental agreements
must be approved by Mortgagee in accordance with the provisions of Paragraph 13
herein.

         Mortgagor shall have the right to contest by appropriate legal
proceedings, but without cost or expense to Mortgagee, the validity of any laws,
ordinances, orders, rules or regulations affecting the Mortgaged Property or the
business conducted thereon if compliance therewith may legally be held in
abeyance without the incurrence of any charge, lien or liability against the
Mortgaged Property and without the loss or suspension of any license, right or
permit with respect to the Mortgaged Property; and in such event Mortgagor may
postpone compliance therewith until the final determination of any such
proceedings, provided that such proceeding is prosecuted with due diligence and
Mortgagee is furnished with security satisfactory to it against any loss or
damage by reason of such noncompliance or contest.

         4. Insurance. With respect to the Mortgaged Property and its use,
Mortgagor will carry, at its expense, such insurance as Mortgagee may from time
to time require including, without limitation, special flood hazard insurance
(if any portion of the Improvements is within a flood zone as shown on the most
recent Flood Insurance Rate Map issued by Federal Emergency Management Agency
with respect to the Mortgaged Property), business interruption insurance and
so-called rent loss insurance (covering business interruptions for at least
twelve (12) months and at least twelve (12) months rent for all leases or
subleases assigned as additional security for the Loan), in each case with an
"extended period of liability" endorsement, and also such insurance as may from
time to time be required by any applicable Federal, State or local law or
regulation. All insurance against loss or damage to the Mortgaged Property by
fire and any of the risks covered by insurance of the type now known as "special
perils" shall contain a "Replacement Cost Endorsement" and an "Agreed Value
Endorsement." Mortgagor shall also acquire and maintain commercial general
coverage for bodily injury and property damage in such amounts as Mortgagee
shall require from time to time or in such amounts as required in any
collateralized leases, whichever is greater. During the construction of any
improvements which become part of the Mortgaged Property, Mortgagor will carry
insurance in "Builder's Risk Completed Value (non-reporting)" form, including
special perils type coverage; all such insurance shall also provide coverage
against perils normally covered by a so-called special endorsement, i.e.,
collapse, cost of demolition, increased cost of construction and the value of
the undamaged portion of the Mortgaged Property. All policies of insurance (with
evidence of payment of premiums thereon satisfactory to Mortgagee) so required
to be maintained, together with any other policies of insurance with respect to
the Mortgaged Property maintained by Mortgagor, shall be deposited with, and,
except for commercial general liability coverage and any other coverage
Mortgagee may determine shall not be payable to it in case of loss, shall be
first payable in case of loss


                                       3
<PAGE>   10
to Mortgagee. All renewals or replacements of such insurance from time to time
in force together with evidence of payment of premiums thereon satisfactory to
Mortgagee shall be delivered to Mortgagee at least sixty (60) days before the
expiration date of then current insurance. All insurance required as aforesaid
to be maintained with respect to the Mortgaged Property shall be written by such
companies, on such terms, in such form, with such endorsements and for such
periods and amounts as Mortgagee shall from time to time approve, and in all
events the policies shall provide that they may not be cancelled, amended or
modified without at least thirty (30) days prior written notice to Mortgagee.
All insurance policies shall provide that copies of any notice of an insurer's
intent not to renew or reissue a policy or to cancel a policy, which may be
required by law to be provided to the insured, shall be forwarded to Mortgagee
at the same time that such notice is issued by the insurer. No settlement on
account of any loss covered by such insurance shall be effected without the
consent and participation of Mortgagee. If an Event of Default (as defined in
Paragraph 20 hereof) occurs, only Mortgagee shall have the right to settle,
adjust and compromise insurance claims.

         Mortgagee shall be notified promptly in the event that (i) any of the
Improvements shall be damaged or destroyed in whole or in part by fire or other
casualty, or (ii) a claim is filed under any insurance policy providing coverage
for Mortgagee.

         5. Application of Certain Insurance Awards. Proceeds paid under any
insurance policy which are required under Paragraph 4 to be paid to Mortgagee
shall, at the option of Mortgagee, be applied to or toward (a) the indebtedness
secured hereby (including principal, whether or not then due and payable,
accrued but unpaid interest and other amounts secured hereby or payable under
the Loan Documents) in such order and in such amounts as Mortgagee shall in its
sole discretion determine, (b) the fulfillment of any covenant contained in the
Loan Documents as Mortgagee may determine in its sole discretion, or (c) the
repair of that part of the Mortgaged Property damaged by the insured hazard. No
interest shall be allowed to Mortgagor on any insurance awards paid to and held
by Mortgagee. Mortgagor hereby covenants and agrees to and with Mortgagee, upon
request by Mortgagee, to make, execute and deliver any and all assignments and
other instruments sufficient for the purpose of assigning the aforesaid award or
awards to Mortgagee free, clear and discharged of any and all encumbrances of
any kind or nature whatsoever. Mortgagor hereby irrevocably appoints Mortgagee
its true and lawful attorney-in-fact, which shall be coupled with an interest,
to assign any policy in the event of the foreclosure of this Mortgage and
Security Agreement or the extinguishment of the indebtedness secured hereby.

         6. Application of Condemnation Awards. The awards of damages on account
of any condemnation for public use of or damage to the Mortgaged Property shall
be paid to Mortgagee. No settlement on account of any damages caused by such
condemnation shall be effected without the consent and participation of
Mortgagee. If an Event of Default (as defined in Paragraph 20 hereof) occurs,
only Mortgagee shall have the right to settle, adjust and compromise
condemnation awards. At the option of Mortgagee, the condemnation award shall be
applied to or toward (a) the indebtedness secured hereby (including principal,
whether or not then due and payable, accrued but unpaid interest and other
amounts secured hereby or payable under the Loan


                                       4
<PAGE>   11
Documents) in such order and in such amounts as Mortgagee shall in its sole
discretion determine, (b) the fulfillment of any covenant contained in the Loan
Documents as Mortgagee may determine in its sole discretion, or (c) the
restoration of that portion of the Mortgaged Properly which remains. Mortgagor
hereby covenants and agrees to and with Mortgagee, upon request by Mortgagee, to
make, execute and deliver any and all assignments and other instruments
sufficient for the purpose of assigning the aforesaid award or awards to
Mortgagee free, clear and discharged of any and all encumbrances of any kind or
nature whatsoever. No interest shall be allowed to Mortgagor on any condemnation
proceeds paid to and held by Mortgagee. Mortgagor hereby irrevocably appoints
Mortgagee its true and lawful attorney-in-fact, which shall be coupled with an
interest, to assign any condemnation awards in the event of the foreclosure of
this Mortgage and Security Agreement or the extinguishment of the indebtedness
secured hereby.

         7. Payment of Taxes and Impositions, Contest Abatement. Subject to the
provisions of Paragraph 8 hereof, Mortgagor will pay not later than fifteen (15)
days before the last date when the same may be paid without interest or penalty,
and by such date will furnish to Mortgagee evidence of payment of, all real
estate tax, personal property taxes, sewer rents, water charges and all other
municipal and governmental rates, charges, assessments and liens (collectively,
"Impositions") which now or hereafter are imposed upon the Mortgaged Property.
If the law imposing any Imposition permits the Imposition to be paid in future
installments, Mortgagor may pay such Imposition in installments as permitted by
law.

         Mortgagor hereby assigns to Mortgagee all rights of Mortgagor now or
hereafter arising in and to any refunds or abatements of Impositions. So long as
no Event of Default exists, Mortgagee shall pay over any such refunds or
abatements to Mortgagor, but, if an Event of Default exists hereunder, then
Mortgagee may apply said refunds or abatements to or toward the indebtedness
secured hereby in such order as Mortgagee may determine.

         8. Reserve Funds. Notwithstanding anything to the contrary contained in
the Loan Documents, Mortgagor, at Mortgagee's option, will pay to Mortgagee on
each date upon which an installment of principal or interest is payable under
the Note, such amount as Mortgagee from time to time estimates is necessary to
create and maintain a reserve fund (the "Reserve Fund Account"), without any
interest thereon accruing to Mortgagor, from which to pay before the same become
due all Impositions, the premiums on insurance policies required to be
maintained by Mortgagor and the ground rents on the Land, if any. Payment from
the Reserve Fund Account of Impositions, insurance premiums and ground rents may
be made by Mortgagee at its discretion, even though subsequent owners of the
Mortgaged Property may benefit thereby. In the event that the balance of the
Reserve Fund Account is insufficient to make such payments, Mortgagor shall
immediately deposit sufficient funds upon notice by Mortgagee. If an Event of
Default occurs, any part or all of said Reserve Fund Account may, at the
election of Mortgagee, be applied to any part of the indebtedness secured
hereby, and, in refunding any part of said Reserve Fund Account, Mortgagee may
deal with whomever it reasonably believes to be the owner of the Mortgaged
Property at that time.


                                       5
<PAGE>   12
         If requested by Mortgagee, and to the extent permitted by law,
Mortgagor shall deliver to Mortgagee all security deposits or other collateral
now or hereafter received from tenants of the Mortgaged Property, to be held and
applied by Mortgagee in accordance with the terms of the respective leases under
which said security deposits were paid, but otherwise without interest accruing
thereon to Mortgagor. In applying or returning such security deposits or
collateral, Mortgagee may deal with whomever it reasonably believes to be
entitled thereto.

        9. No Prior Liens: Transfers of Security: Change in Name. Principal
Place of Business or Chief Executive Office.

(a) Mortgagor will pay, prior to the date when any interest or penalty accrues,
all sums which if not paid may result in the creation of a lien prior to the
encumbrance of this instrument, or which if not paid may confer upon a tenant of
the Mortgaged Property a right to pay such sums and treat the payment as prepaid
rent.

(b) Mortgagor will not create or permit, and will promptly discharge, any
security interest, mortgage, lien or other encumbrance or financing statement on
the Security superior to the encumbrance created by this instrument. Mortgagor
will not create or permit, and will promptly discharge, any security interest,
mortgage, lien or other encumbrance or financing statement on the Security
inferior to the encumbrance created by this instrument without the prior written
consent of the Mortgagee.


(c) Mortgagor will not cause or permit, whether voluntarily or involuntarily,
any transfer (including without limitation any sale, assignment, gift or
foreclosure) of the Security or any part thereof without the prior written
consent of the Mortgagee.

(d) Mortgagor will not cause or permit any change in its name, or change in the
location of its place of business or its chief executive office, without first
giving notice of such change to Mortgagee (which notice shall specifically refer
to this Paragraph 9(d)) and simultaneously causing to be recorded or
re-recorded, registered or re-registered and filed or re-filed such replacement
or supplementary financing statements under the Uniform Commercial Code, and
such other instruments as may be required by law or deemed advisable by
Mortgagee, to create, preserve or protect the encumbrance hereof upon the
Security or any part thereof.

(e) Mortgagor has fully disclosed to Mortgagee all facts material to the
Security, the Mortgagor, the Mortgagor's business operations, and any endorser
or guarantor of the Note.

         10. Mortgagee's Right to Cure. If Mortgagor shall fail (a) to maintain
and keep in good repair the Mortgaged Property as required herein, (b) to
maintain the coverage and pay the premiums for insurance required herein, (c) to
pay and discharge all Impositions as required herein, (d) to pay the sums
required to be paid pursuant to the provisions of Paragraphs 8 and 9, or (e) to
satisfy any other term or condition of this instrument, Mortgagee may, at its
election, cause such repairs to be made, obtain such insurance, pay Impositions,
pay the sums required to be paid under Paragraphs 8 and 9 and pay any sums
necessary to discharge any liens or encumbrances on the Security prohibited
hereby, incur and pay amounts in protecting its rights hereunder and the
security hereby granted, pay any balance due under any conditional agreement of
sale of any property constituting a part of the Mortgaged Property and pay any
amounts Mortgagee deems necessary or appropriate to satisfy


                                       6
<PAGE>   13
any term or condition of this instrument which Mortgagor shall have failed to
satisfy, or to remedy any breach of such term or condition. Any amounts or
expenses so paid or incurred, together with interest thereon from the date of
payment by Mortgagee at the Fixed Rate of interest provided in the Note plus
seven percent (7%) per annum, but in no event more than the maximum rate allowed
by law, shall be immediately due and payable by Mortgagor to Mortgagee and until
paid shall be added to and become a part of the principal debt secured hereby,
and the same may be collected as part of said principal debt in any suit hereon
or upon the Note. No payment by Mortgagee shall relieve Mortgagor from any
default hereunder or impair any right or remedy of Mortgagee.

         11. Mortgagee's Costs and Attorneys' Fees. If any action or proceeding
be commenced, including but not limited to an action to foreclose this
instrument or to collect the debt secured hereby, to which action or proceeding
Mortgagee is made a party by reason of the execution of this instrument or by
reason of any obligations which it secures, or by reason of entry or any other
action under this instrument, or if it becomes necessary in connection with
legal proceedings or otherwise to defend or uphold this instrument or any act
taken under this instrument, all sums paid or incurred by Mortgagee for the
expense of any litigation or otherwise in connection with any rights created by
this instrument (including its attorneys' fees and expenses) with interest
thereon from the date of payment by Mortgagee at the Fixed Rate of interest
provided in the Note plus seven percent (7%) per annum, but in no event more
than the maximum rate allowed by law, shall be immediately due and payable by
Mortgagor to Mortgagee, and until paid shall be added to and become a part of
the principal debt secured hereby, and the same may be collected as part of said
principal debt in any suit hereon.

         Mortgagor also agrees that Mortgagee may charge administrative fees and
be reimbursed for all costs and expenses, including, without limitation, its
attorneys' fees and expenses, associated with reviewing and processing
post-closing requests by Mortgagor in connection with the Loan.

         12. Subrogation. Mortgagee shall, in addition to all other rights, be
subrogated for further security to the Security, although paid or discharged of
record, of any and all encumbrances on the Security or any part thereof to the
extent satisfied by funds of Mortgagee, whether paid out of the proceeds of the
Loan secured by this instrument or otherwise.

         13. Assignment of Rents, Leases and other Contracts: Compliance with
Leases: Future Leases. Mortgagor warrants to Mortgagee that the Mortgage
Property is completely occupied by Mortgagor and that there are no leases,
tenancies or licenses affecting the Mortgaged Property.

As further security for payment of the sums secured hereby, Mortgagor hereby
transfers, assigns and sets over unto Mortgagee all future leases and tenancies
of space in the Mortgaged Property and all modifications and renewals thereof
and all guarantees thereof, together with the right to sue for, collect and
receive all rents and other sums to be paid to the landlord thereunder, and all
damages payable by any tenant upon default under any lease, and also together
with the right to enforce any and all of the agreements, terms, covenants and
conditions in said leases and


                                       7
<PAGE>   14
guarantees thereof and to give notices thereunder. The foregoing assignment
shall not be construed as a consent by the Mortgagee to any lease so assigned or
to impose upon the Mortgagee any obligation with respect thereto. Mortgagor
covenants and agrees to faithfully keep and perform all of the obligations of
the landlord under all of the leases hereafter assigned to Mortgagee and will
not permit to accrue to the account of any tenant under any such lease any
payments other than the usual prepayment of rent as would result from the
acceptance on the first day of each month of the rent for the ensuing months,
according to the terms of the various leases.

         Unless Mortgagee shall first consent in writing, Mortgagor will not
hereafter (a) enter into or make any lease to any tenant; (b) modify, amend,
terminate, cancel, or renew (other than a renewal to which a tenant is entitled
under the terms of an existing lease) any lease of any portion of the Mortgaged
property; or (c) accept the surrender of any portion of the Mortgaged Property
subject to any existing lease. With respect to any portion of the Mortgaged
Property, unless Mortgagee shall first consent in writing, Mortgagor will not
hereafter (i) permit to accrue to any tenant in the Mortgaged Property any right
to prepay rent pursuant to the terms of any lease other than the usual
prepayment of rent as would result from the acceptance by the landlord on the
first day of each month of the rent for the ensuing month, according to the
terms of the various leases, unless otherwise provided in existing leases; or
(ii) reduce the payment of the rent thereunder or accept any prepayment of rent
therein (except any amount which may be required to be prepaid by the terms of
any such lease).

         Mortgagor will furnish to Mortgagee a true and complete signed copy of
each lease, or renewal of lease, hereafter made by Mortgagor with respect to any
portion of the Mortgaged Property within ten (10) days after final execution of
each such lease. Each such lease or a memorandum thereof shall be executed in a
form proper for recording with the Middlesex South District Registry of Deeds
and filing with the Middlesex South Registry District of the Land Court, which
lease or memorandum shall be recorded and filed for registration by Mortgagor at
the option of Mortgagee. Mortgagor shall enforce in the ordinary course of
business all of the agreements, terms, covenants, and conditions of said leases
to be performed by the tenant thereunder. Mortgagor shall perform in such
ordinary course of business every obligation of the landlord under any lease of
space at the Mortgaged Property, and shall not suffer or permit there to exist
any default in such performance or permit any event to occur which would give
the tenant under any such lease the right to terminate same and shall not
modify, abridge, waive, terminate or cancel any such lease or tenancy. Any and
all tenants' security deposits under any and all leases or tenancies of any part
or all of the Mortgaged Property shall, at the option of Mortgagee, be deposited
with Mortgagee or, if required by applicable law, deposited in an account at a
bank acceptable to Mortgagee so that they cannot be used by Mortgagor without
the consent of Mortgagee, and in the event of a commencement of a foreclosure of
this Mortgage or the conveyance of the Mortgaged Property to Mortgagee in lieu
of foreclosure, these deposits shall be transferred to Mortgagee if title is
acquired by Mortgagee or to the purchaser in the event of a foreclosure sale.

         Mortgagor shall furnish to Mortgagee, within ten (10) days after
receipt thereof, or the mailing or service thereof by Mortgagor, as the case may
be, a copy of each notice


                                       8
<PAGE>   15
of default which Mortgagor shall give to or receive from, any tenant of the
Mortgaged Property or of any part thereof, based upon the


                                       9
<PAGE>   16
occurrence, or alleged occurrence, of any default or defaults in the performance
of any covenant, condition, promise or obligation provided for in a lease of any
space at the Mortgaged Property. Mortgagor shall furnish to Mortgagee an
attornment agreement in form and substance reasonably satisfactory to Mortgagee
with respect to any such tenant of the Mortgaged Property.

         Nothing in this Mortgage and Security Agreement, and no exercise by the
Mortgagee of its rights hereunder shall be construed to obligate the Mortgagee
to perform any of the covenants of Mortgagor as landlord under any of the leases
hereinabove assigned or shall be deemed to constitute Mortgagee a mortgagee in
possession in the absence of an actual entry into and taking of possession of
the Mortgaged Property by Mortgagee.

         All agreements and obligations to pay commissions or fees in connection
with the leasing of any portion of the Mortgaged Property shall be subject and
subordinate to this Mortgage and Security Agreement and shall not be enforceable
against Mortgagee, any purchaser at a foreclosure sale hereunder, or their
respective successors and assigns.

         All leases of all or any portion of the Mortgaged Property made
hereafter shall be subject and subordinate to this Mortgage, except as otherwise
provided herein, unless Mortgagee requests that they be superior, in which case
Mortgagor shall cause such lease to be superior to this Mortgage in a manner
acceptable to Mortgagee. All such leases shall contain a provision providing
that Mortgagee may, at its election, record an instrument executed by the
Mortgagee providing that each such lease is superior to this Mortgage, which
instrument upon recording with said Registry of Deeds and filing with said
Registry District shall be sufficient to cause each such lease to be superior to
this Mortgage. Upon recording with said Registry of Deeds and filing with said
Registry District such an instrument providing that one or more of such leases
are superior to this Mortgage and Security Agreement, the lease or leases
referred to therein shall be superior to this Mortgage and Security Agreement.

         In addition, upon request by Mortgagee, Mortgagor shall transfer,
assign and set over unto Mortgagee all other agreements, contracts, licenses and
permits affecting the Mortgaged Property, such assignments to be made by
instruments in form satisfactory to the Mortgagee.

         14. Protection of Encumbrance; Mortgagor's Estoppel Certificate.
Mortgagor will, on the request of Mortgagee, furnish a written list of all
fixtures and other articles of personal property (tangible and intangible)
belonging to Mortgagor located on the Real Property, and will, at Mortgagor's
expense, promptly cause this Mortgage and Security Agreement and financing
statements prepared pursuant to the Uniform Commercial Code, to be recorded and
re-recorded, registered and re-registered, filed and re-filed at such times and
places as may be required by law or deemed advisable by Mortgagee to create,
preserve or protect the encumbrance and priority hereof upon the Security or any
part thereof; and Mortgagor will from time to time do and cause to be done all
such things as may be required by Mortgagee or required by law, including all
things which may from time to time be necessary under the Uniform Commercial
Code, fully to create, preserve and protect the encumbrance and priority hereof
upon the Security or


                                       10
<PAGE>   17
any part thereof. A carbon, photographic or other reproduction of this Mortgage
and Security Agreement or a financing statement shall be sufficient as a
financing statement. Mortgagor hereby irrevocably appoints Mortgagee its true
and lawful attorney-in-fact, which shall be deemed to be coupled with an
interest, to execute, acknowledge and deliver any such instruments on behalf of
Mortgagor which Mortgagor fails or refuses to do. This power of attorney shall
not be affected by subsequent disability or incapacity of the principal. If an
Event of Default occurs, Mortgagee may require Mortgagor to assemble the
Security which constitutes personal property and make it available to Mortgagee
at a place to be designated by Mortgagee which is reasonably convenient to both
parties.

         On the request of Mortgagee, Mortgagor shall furnish a written
statement, signed and, if requested, acknowledged, setting forth the amount of
the indebtedness which Mortgagor acknowledges to be due on the Note and under
this Mortgage and Security Agreement, specifying any claims of offset or defense
which Mortgagor asserts against the indebtedness secured hereby or any
obligation to be paid or performed hereunder, and the then state of facts
relative to the condition of the Security.

         15. Hazardous Materials. As used herein and in the Loan Documents,
"Hazardous Materials" shall mean and include, but shall not be limited to, any
petroleum product and all hazardous or toxic substances, wastes or substances,
any substances which because of their quantitative concentration, chemical,
radioactive, flammable, explosive, infectious or other characteristics,
constitute or may reasonably be expected to constitute or contribute to a danger
or hazard to public health, safety or welfare or to the environment, including,
without limitation, any asbestos (whether or not friable) and any
asbestos-containing materials, waste oils, solvents and chlorinated oils,
polychlorinated biphenyls (PCBs), toxic metals, etchants, pickling and plating
wastes, explosives, reactive metals and compounds, pesticides, herbicides, radon
gas, urea formaldehyde foam insulation and chemical, biological and radioactive
wastes, or any other similar materials or any hazardous or toxic wastes or
substances which are included under or regulated by any federal, state or local
law, rule or regulation (whether now existing or hereafter enacted or
promulgated, as they may be amended from time to time) pertaining to
environmental regulations, contamination, clean-up or disclosures, and any
judicial or administrative interpretation thereof, including any judicial or
administrative orders or judgments, including, without limitation, the
Comprehensive Environmental Response, Compensation and Liability Act of 1980, 42
U.S.C. Section 9601 et seq. ("CERCLA"); The Federal Resource Conservation and
Recovery Act, 42 U.S.C. Section 6901 et seq. ("RCRA"); Superfund Amendments and
Reauthorization Act of 1986, Public Law No. 99-499 (signed into law October 17,
1986) ("SARA"); Toxic Substances Control Act, 15 U.S.C. Section 2601 et seq.
("TSCA"); Massachusetts Oil and Hazardous Material Release Prevention and
Response Act, M.G.L. c. 21 E; Massachusetts Hazardous Waste Management Act,
M.G.L. c. 21C; the Hazardous Materials Transportation Act, 49 U.S.C. Section
1801 et seq.; or any other state superlien or environmental clean-up or
disclosure statutes (all such laws, rules and regulations being referred to
collectively as "Environmental Laws.).

         For purposes of this Paragraph 15, "affiliate" shall mean and include
any entity which is in control of, controlled by, or under common control with
Mortgagor.


                                       11
<PAGE>   18
        Subject to the matters disclosed in the Environmental Certificate,
Mortgagor Warrants, represents and covenants as follows:

(a) Mortgagor has performed reasonable investigations, studies and tests as to
any possible environmental contamination, liabilities or problems with respect
to the Mortgaged Property and such investigations, studies and tests have
disclosed no Hazardous Materials or possible violations of any Environmental
Laws.

(b) To the best of Mortgagor's knowledge, there have been no releases of
Hazardous Materials either at, upon, under or within the Mortgaged Property, and
no Hazardous Materials have migrated to the Mortgaged Property. No Hazardous
Materials are heated on or have been stored, processed or disposed of on, or
released or discharged from (including ground water contamination) the
Mortgaged Property or any other property currently owned or operated by
Mortgagor or any affiliate of Mortgagor, and no above or underground storage
tanks exist on the Mortgaged Property.

(c) Mortgagor shall not allow any Hazardous Materials to exist or be stored,
located, discharged, possessed, managed, processed or otherwise handled on the
Mortgaged Property or any other property currently or subsequently owned or
operated by Mortgagor or any affiliate of Mortgagor, and shall strictly comply
with all Environmental Laws affecting the Mortgaged Property or such other
property currently or subsequently owned or operated by Mortgagor, including
those laws regarding the generation, storage, disposal, release and discharge of
hazardous substances. Without limiting the generality of the foregoing,
Mortgagor has not been, is not, and will not become involved in operations at
the Mortgaged Property or any other property currently or subsequently owned or
operated by Mortgagor which could lead to imposition on Mortgagor of liability
under any Environmental Law, including without limitation M.G.L. c.21 E.
Mortgagor expressly warrants, represents and covenants that Mortgagor shall
strictly comply with all requirements under M.G.L. c.21 E, and shall immediately
notify Mortgagee of any releases of oil or Hazardous Materials at, upon, under
or within the Mortgaged Property.

(d) Neither Mortgagor, the Mortgaged Property nor any other property currently
or previously owned or operated by Mortgagor or any affiliate of Mortgagor (i)
has received notice of or is subject to any private or governmental lien or
judicial or administrative notice, order or action relating to Hazardous
Materials or environmental problems, impairments or liabilities with respect to
the Mortgaged Property or such other property, or (ii) is in, or with any
applicable notice or lapse of time, or failure to take certain curative or
remedial actions, will be in, either direct or indirect violation of any
Environmental Laws.

(e) Mortgagor has not received any notice of any release of Hazardous Materials
with respect to the Mortgaged Property or any other property previously owned or
operated by Mortgagor from any governmental, judicial or administrative
authority or from any tenant or other occupant of the Mortgaged Property, or any
other property previously owned or operated by Mortgagor.

(f) Mortgagor shall strictly comply with the requirements of all Environmental
Laws affecting the Mortgaged Property and any other property currently or
subsequently owned or operated by Mortgagor.


                                       12
<PAGE>   19
(g) No activity shall be undertaken on the Mortgaged Property or any which would
cause (i) the Mortgaged Property or such other property to be considered a
hazardous waste treatment, storage or disposal facility as defined under any
Environmental Laws; (ii) a release or threatened release of Hazardous Materials
from the Mortgaged Property or such other property in violation of any
Environmental Laws; or (iii) the discharge of Hazardous Materials into any
watercourse, surface or subsurface water or wetland, or the discharge into the
atmosphere of any Hazardous Materials in each case requiring a permit under any
Environmental Laws and for which no such permit has been issued.

(h) Mortgagor shall immediately notify Mortgagee in writing should Mortgagor
become aware of (i) any release or threatened release of Hazardous Materials or
the occurrence of any other environmental problem or liability with respect to
the Mortgaged Property, any other property currently, previously or subsequently
owned or operated by Mortgagor or any affiliate of Mortgagor, or any real
property adjoining or in the vicinity of the Mortgaged Property or such other
property which could subject Mortgagor, the Mortgaged Property or such other
property to a claim under any Environmental Laws or to any restriction on
ownership, occupancy, transferability or use of the Mortgaged Property or such
other property under any Environmental Laws, (ii) any lien filed, action taken
or notice given of the nature described in subparagraph (d) above, (iii) any
notice given to Mortgagor from any tenant or other occupant of the Mortgaged
Property or any other property currently, previously or subsequently owned or
operated by Mortgagor or any affiliate of Mortgagor or any notice from any other
person with respect to any release or threatened release of Hazardous Materials,
or (iv) the commencement of any litigation or threat of litigation relating to
any alleged unauthorized release of any Hazardous Materials or other
environmental contamination, liability or problem with respect to or arising out
of or in connection with the Mortgaged Property or any other property currently,
previously or subsequently owned or operated by Mortgagor or any affiliate of
Mortgagor. Mortgagor shall deliver to Mortgagee any documentation or records as
Mortgagee may reasonably request and which are susceptible of being obtained by
Mortgagor without undue cost or expense and without the necessity for initiating
legal proceedings to obtain the same in connection with all such notices,
inquiries and communications, and shall endeavor to advise Mortgagee of any
subsequent developments. Mortgagor shall, at its own cost and expense, take all
actions (to the extent and at the time or from time to time) as shall be
necessary or other property currently or subsequently owned or operated by
Mortgagor advisable for the clean-up of the Mortgaged Property or such other
property currently, previously or subsequently owned or operated by Mortgagor or
any affiliate of Mortgagor, including all removal, containment and remedial
actions in accordance with all applicable Environmental Laws (and in all events
in a manner satisfactory to Mortgagee), and shall further pay or cause to be
paid at no expense to Mortgagee all clean-up, administrative, and enforcement
costs of applicable government agencies or the parties protected by such
Environmental Laws which may be asserted against the Mortgaged Property or such
other property currently or subsequently owned or operated by Mortgagor, or any
affiliate of Mortgagor or any other owner or operator of the Mortgaged Property,
or a lienholder secured thereby. All costs (including, without


                                       13
<PAGE>   20
limitation, those costs set forth above), damages, liabilities, losses, claims,
expenses (including attorneys' fees and disbursements) which are incurred by
Mortgagee, without the requirement that Mortgagee wait for the ultimate outcome
of any litigation, claim or other proceeding, shall be paid by Mortgagor to
Mortgagee within ten (10) days after notice to Mortgagor from Mortgagee
itemizing the amounts incurred to the effective date of such notice, with
interest thereon from the date of payment by Mortgagee at the Fixed Rate of
interest provided in the Note plus seven percent (7%) per annum, but in no event
more than the maximum rate allowed by law. Until such amounts due and payable
shall be paid by Mortgagor, they shall be added to and become a part of the
principal debt secured hereby, and the same may be collected as part of said
principal debt in any suit hereon or upon the Note. At any time until the
indebtedness evidenced by the Note has been paid in full and the obligations of
the Loan are completely satisfied Mortgagee may, with no obligation to, enter
the Mortgaged Property to make reasonable inspections and tests thereof related
to the possible presence or threat of Hazardous Materials.

(i) Mortgagor hereby warrants and represents that all of the answers on a
certain Environmental Certificate executed on February 27, 1997 (the
"Environmental Certificate") in connection with Mortgagor's application for the
Loan are true and complete as of the date hereof. Mortgagor shall immediately
notify Mortgagee in writing should Mortgagor become aware that any of the
answers on the Environmental Certificate either (i) was not true at the time the
Environmental Certificate was executed or (ii) becomes untrue during the course
of the Loan.

(j) Mortgagor hereby covenants and agrees to unconditionally and absolutely
indemnify and save harmless Mortgagee, its officers, directors, shareholders,
employees, agents and attorneys against and from any and all damages, losses,
liabilities, obligations, claims, litigation, demands, defenses, judgments,
suits, proceedings, fines, penalties, costs, disbursements and expenses
(including, without limitation, attorneys' and experts' fees and expenses,
clean-up costs, waste disposal costs and those costs, expenses, penalties and
fines within the meaning of CERCLA), of any kind or nature whatsoever which may
at any time be imposed upon, incurred by or asserted or awarded against
Mortgagee and arising from any environmental matter described in this Mortgage
and Security Agreement, including, without limitation, matters arising out of
any breach of Mortgagor's foregoing representations and warranties, whether any
such matters arise before or after foreclosure of this Mortgage and Security
Agreement (or deed in lieu thereof or similar actions to the same effect).
Mortgagor does further agree and covenant that Mortgagee shall not assume any
liability or obligation for loss, damage, fines, penalties, claims or duty to
clean up or dispose of Hazardous Materials, or other wastes or materials, on or
relating to the Mortgaged Property or any other property currently, previously
or subsequently owned or operated by Mortgagor or any affiliate of Mortgagor,
regardless of any inspections or other actions made or taken by Mortgagee on
such property or as a result of any conveyance of title to the Mortgaged
Property to Mortgagee or otherwise. All warranties and representations above
shall be deemed to be continuing and shall remain true and correct in all
material respects until the indebtedness has been paid in full, the obligations
completely satisfied, and any limitations period with respect to any claims
under each of the Environmental Laws has


                                       14
<PAGE>   21
expired. The covenants of Mortgagor contained herein shall survive any exercise
of any remedy by Mortgagee under the Loan Documents, including foreclosure of
this Mortgage and Security Agreement (or deed in lieu thereof or similar actions
to the same effect), even if, as a part of such foreclosure, deed in lieu of
foreclosure or similar action, the indebtedness secured hereby is satisfied in
full. Mortgagor agrees that the indemnification granted herein may be enforced
by Mortgagee without resorting to or exhausting any other security or collateral
or without first having recourse to the Note or the Mortgaged Property covered
by this Mortgage and Security Agreement through foreclosure proceedings or
otherwise; provided, however, that nothing herein contained shall prevent
Mortgagee from suing on the Note or foreclosing this Mortgage and Security
Agreement or from exercising any other rights under the Loan Documents.

         16. Certain Rights. of Mortgagee re: Successors. Guarantors etc.
Without affecting the liability of Mortgagor or any other person (except any
person expressly released in writing) for payment of any indebtedness secured
hereby or for performance of any obligation contained herein or in the Loan
Documents, and without affecting the rights of Mortgagee with respect to any
security not expressly released in writing, Mortgagee may, at any time and from
time to time, either before or after the maturity of the Note, and without
notice or consent:

(a) Deal with any successor in interest of Mortgagor herein regarding this
instrument and the debt hereby secured in all respects as it might deal with
Mortgagor herein, it being understood and agreed that no sale of Security shall
operate to release, discharge, modify, change or affect the original liability
of any predecessor in interest of the equity owner at the time of such sale,
forbearance or extension.

(b) Release any person liable for payment of all or any part of the indebtedness
or for performance of any obligation.

(c) Make any agreement extending the time or otherwise altering the terms of
payment of all or any part of the indebtedness, or modifying or waiving any
obligation, or subordinating, modifying or otherwise dealing with the
encumbrance or charge hereof.

(d) Exercise or refrain from exercising or waive any right Mortgagee may have.

(e) Accept additional security of any kind.

(f) Release or other wise deal with any property, real or personal, securing the
indebtedness, including all or part of the Security.

         17. Mortgagor's Books and Records. Mortgagor shall maintain current and
accurate books and records showing in detail satisfactory to Mortgagee the
operation of the Mortgaged Property and any business conducted thereon by
Mortgagor, and Mortgagee shall have the right to inspect and copy such books and
records.

         Mortgagor shall deliver to Mortgagee within ninety (90) days after the
close of Mortgagor's fiscal year, balance sheets and statements of annual income
and expense, in form and substance acceptable to Mortgagee, for the preceding
year for Mortgagor and for the Mortgaged Property, and shall deliver to
Mortgagee such other information with respect to Mortgagor and the Mortgaged
Property as Mortgagee may reasonably request from time to time, including, but
not limited to, a rent roll for the Mortgaged Property, including tenant names,
base commencement and expiration dates, square footage, annual rent, expense
contributions and any other information Mortgagee may request. All financial
statements shall be accompanied by a certification of an


                                       15
<PAGE>   22
independent certified public accountant, who is a member of the American
Institute of Certified Public Accountants, certifying that such statements are
accurate and are in accordance with generally accepted accounting principles,
consistently applied or, at Mortgagee's option, by a certification of the
financial officer of Mortgagor who is responsible for the preparation of such
financial statements.

         18. Mortgagor's Authority. Mortgagor represents and warrants to
Mortgagee that it is a corporation duly organized and validly existing under the
laws of the State of Delaware and is duly qualified to do business in the
Commonwealth of Massachusetts, that it has the requisite power and authority to
enter into the Loan evidenced by the Note, to execute and deliver all of the
Loan Documents and to perform all of the obligations of the Mortgagor under the
Loan Documents.

         19. Change in Law. In the event of the passage of any state, federal,
municipal or other governmental law, order, rule or regulation, subsequent to
the date hereof, in any manner changing or modifying the laws now in force
governing the taxation of mortgages or debts secured by mortgages or the manner
of collecting taxes so as to affect adversely Mortgagee, all sums secured by
this Mortgage and Security Agreement and all interest accrued thereon shall,
without notice, become due and payable forthwith at the option of Mortgagee;
provided, however, Mortgagee shall not make such election if Mortgagor is
permitted by law to pay such tax, and if, within ten (10) days after the
imposition of such tax, Mortgagor does pay such tax and all other payments
required hereunder and agrees to pay any such tax when thereafter levied or
assessed against the Mortgaged Property.

         20. Events of Default. The entire indebtedness secured hereby shall
become immediately due and payable at the option of Mortgagee without notice to
Mortgagor, and an Event of Default shall exist hereunder, if (a) any default
shall occur under the Note; (b) the liquidation, winding-up, termination of
existence or dissolution of the organization of Mortgagor, any endorser or
guarantor of the Note, or any signatory to any other instrument securing the
Note, or the cessation of the business activities as presently conducted by
Mortgagor or any guarantor of the Note; (c) Mortgagor, any endorser or guarantor
of the Note, or any signatory to any other instrument securing the Note grants a
trust mortgage, or executes a general assignment for the benefit of creditors,
or fails to generally pay its debts as they mature, or petitions or applies for
the appointment of a liquidator or a receiver of Mortgagor, any endorser or
guarantor of the Note, or any signatory to any other instrument securing the
Note, or of any substantial part of the assets of Mortgagor, any endorser or
guarantor of the Note, or any signatory to any other instrument securing the
Note, or commences any proceeding under any bankruptcy, reorganization,
insolvency, readjustment of debt, dissolution or liquidation law or similar law
of any jurisdiction, now or hereafter in effect, or any order for relief shall
be entered in any such proceeding, or Mortgagor, any endorser or guarantor of
the Note, or any signatory to any other instrument securing the Note, shall
acquiesce to the entry of an order for relief in any such proceeding; (d) the
filing of any petition or application commencing any proceeding against
Mortgagor, any guarantor or endorser of the Note, or any signatory to any other
instrument securing the Note, under any bankruptcy, reorganization, insolvency,
readjustment of debt, dissolution or liquidation law or similar law of any
jurisdiction, now or hereafter in effect, where such


                                       16
<PAGE>   23
petition or application is not dismissed within thirty (30) days after the date
such petition or application was filed, or where such proceeding is not
dismissed or stayed within thirty (30) days after the date such proceeding was
commenced; (e) the Security or any part thereof or any interest therein, or any
legal or beneficial interest in Mortgagor, shall be transferred in violation of
Paragraph 9 hereof or Mortgagor shall cause or permit a change in its name,
place of business or chief executive office in violation of the provisions of
Paragraph 9(d) hereof; (f) any security interest, lien or other encumbrance or
financing statement shall be created on the Security or any part thereof by
operation of law or otherwise in violation of the requirements of Paragraph 9
hereof; (9) any default shall occur under any other mortgage which Mortgagor has
not cured or is not proceeding with diligence to cure pursuant to the terms of
such other mortgage or any other encumbrance or lien of any kind on the Security
or any part thereof, or any foreclosure thereof shall be commenced; (h) any levy
or sale upon execution or other proceedings of any nature shall occur whereby
Mortgagor shall be deprived of its title or right of possession to the Security
or any part thereof; (i) any license or permit to operate the business conducted
on the Mortgaged Property by Mortgagor is suspended or revoked and such
suspension or revocation is not terminated within thirty (30) days; (j)
Mortgagor shall default under Paragraph 4 hereof relating to insurance, under
Paragraph 7 hereof relating to Impositions, under Paragraph 13 hereof relating
to leases or under Paragraph 15 hereof relating to Environmental Laws and
Hazardous Materials; (k) the answers on the Environmental Certificate become
untrue; (l) the Mortgaged Property or any part thereof shall be abandoned by
Mortgagor; (m) any statement, representation or warranty made herein, in
connection with the application for the Loan, in any supporting financial
statement or in any other Loan Document by Mortgagor, any endorser or guarantor
of the Note, or any signatory to any other instrument securing the Note shall
prove to have been false, misleading or erroneous in any material respect when
made; (n) Mortgagor, as lessor or assignor, shall fail to observe, comply with,
adhere to or perform any agreement of Mortgagor in any lease relating to the
Mortgaged Property or any assignment thereof; (o) the Mortgaged Property or any
other property owned or operated by Mortgagor becomes subject to any claim,
notice or action under the Environmental Laws described in Paragraph 15 hereof;
(p) the death or adjudicated incompetence of Mortgagor (or any beneficial owner
of Mortgagor), any endorser or guarantor of the Note, or any signatory to any
other instrument securing the Note and if any of the Mortgagor, its beneficiary,
or any such signatory, any endorser or guarantor is a partnership, the death or
adjudicated incompetence of any partner; or (q) any default in the performance
or observance of any other provision hereof or in any of the Loan Documents
shall occur.

       21. Remedies. While any Event of Default exists hereunder, Mortgagee may,
at its option and without notice, exercise any or all of the following remedies:

(a) apply to the indebtedness secured hereby any sums then held or thereafter
received by Mortgagee including, without limitation, any insurance proceeds,
condemnation awards and reserve funds held for payment of Impositions, insurance
premiums and ground rents;


                                       17
<PAGE>   24
(b) declare all indebtedness secured hereby to be immediately due and payable
and the same shall thereupon become immediately due and payable without any
presentment, demand, protest or notice of any kind;

(c) take possession of the Security and use, operate, manage and control the
same and conduct the business thereof and collect the income therefrom all to
the extent and on such terms and conditions as Mortgagee shall, in its judgment,
determine to be appropriate for the maintenance and preservation of the Security
or of the value thereof, such determination to be conclusive in the absence of
bad faith. Without limiting the generality of the foregoing, Mortgagee may take
any one or more of the following actions: (1) use and operate the Mortgaged
Property itself or through a subsidiary or affiliate, or hire a professional
property manager at Mortgagor's expense to do the same; (2) receive, collect,
compromise and settle any or all accounts receivables, accounts or contract
rights arising from or relating to the Mortgaged Property or any business
conducted thereon, and Mortgagor hereby irrevocably appoints Mortgagee its true
and lawful attorney-in-fact, which shall be deemed to be coupled with an
interest (and which power of attorney shall not be affected by subsequent
disability or incapacity of the principal), to take all action in its name for
such purposes, including, without limitation, the right to request delivery of
mail and endorse checks and drafts with the name of Mortgagor to the same extent
as Mortgagor itself shall be entitled to endorse; take possession of, use and
consume all inventory; use the name and good will of any business conducted by
Mortgagor on the Mortgaged Property; care for and exercise all rights with
respect to all tenants, occupants or customers; and possess and use the books
and records showing the operation of the Mortgaged Property or any business
previously conducted by Mortgagor on the Mortgaged Property; (3) apply any
amounts received by Mortgagor in connection with the Assignments to the payment
of the indebtedness and to the expenses of leasing, operating, maintaining and
managing the Mortgaged Property, as more fully described in the Assignments; (4)
lease the Mortgaged Property or any portion thereof for itself as Mortgagee and
as Mortgagor's attorney-in-fact so that any such lease shall bind both Mortgagor
and Mortgagee in accordance with its terms notwithstanding any foreclosure or
redemption; (5) from time to time at the expense of Mortgagor make all such
repairs, replacements, alterations, additions and improvements to the Mortgaged
Property as Mortgagee may deem proper; and (6) pay and incur all expenses
necessary or deemed by it appropriate for operating the Mortgaged Property and
the conduct of any then existing business thereon including, without limitation,
Impositions, insurance, wages of employees connected with the Mortgaged Property
or the business conducted thereon, charges and reasonable compensation for
services of Mortgagee, its attorneys and accountants and all other persons
engaged or employed in connection with the Mortgaged Property or any business
conducted thereon and, in addition, Mortgagee, at its option, may make payments
or incur liability with respect to obligations arising prior to the date it
takes possession. All activities of Mortgagee hereunder shall be undertaken by
Mortgagee as mortgagee-in-possession for the maintenance and preservation of its
collateral and not as successor to any business or activities of Mortgagor, and
Mortgagee shall be without any liability, charge or obligation therefor to
Mortgagor.


                                       18
<PAGE>   25
(d) seek the appointment of a receiver for all or any part of the Mortgaged
Property. Mortgagor hereby consents to such appointment and waives any and all
defenses to such appointment;

(e) sell all or any portion or portions of the Security pursuant to the
provisions of Paragraph 22 hereof;

(f) without taking possession of the Mortgaged Property, sue for or otherwise
collect and receive all earnings, revenues, issues, profits, rents and other
income otherwise payable to Mortgagor pursuant to all present and future leases
of space in the Mortgaged Property; or

(g) take such other action as may legally be available to Mortgagee to protect
its interest in the Security and to collect the indebtedness due it.

         22. Statutory Condition and Statutory Power of Sale. This instrument is
upon the STATUTORY CONDITION and upon the further condition that all covenants
and agreements of Mortgagor contained herein, in the Note and in the other Loan
Documents shall be kept and fully performed, and upon any breach of such
covenants and agreements or if an Event of Default shall exist hereunder
Mortgagee shall have, as to the Real Property, the STATUTORY POWER OF SALE, and
as to all other portions of the Security, all the remedies of a secured party
under the Uniform Commercial Code.

         In exercising its power of sale under this instrument Mortgagee may
sell the personal property or any part thereof, either separately from or
together with the Real Property or any part thereof, either as one unit or
separately as Mortgagee may in its discretion elect, and may sell the Mortgaged
Property as a whole or in separate parts as Mortgagee may in its discretion
elect Mortgagor hereby waiving, on behalf of itself and its successors and
assigns, the application of any doctrine of marshalling. In case Mortgagee
elects to sell the Mortgaged Property in parts or parcels, said sales may be
held from time to time, and the power shall not be exhausted until all of the
Mortgaged Property not previously sold shall have been sold. In the event of any
separate sale of personal property, Mortgagee will give to Mortgagor reasonable
notice of the time and place of any public sale or of the time after which any
private sale or other intended disposition thereof is to be made, and such
requirement of reasonable notice shall be met if such notice is mailed postage
prepaid to the address of Mortgagor set forth at the beginning of this
instrument at least ten (10) days before the time of the sale or other
disposition.

         23. Indemnification. Mortgagor hereby covenants and agrees
unconditionally and absolutely to indemnify and save harmless Mortgagee, its
officers, directors, shareholders, employees, agents and attorneys against all
damages, losses, liabilities, obligation, claims, litigation, demands or
defenses, judgments, suits, proceedings, fines, penalties, costs, disbursements
and expenses of any kind or nature whatsoever which may at any time be imposed
upon, incurred by or asserted or awarded against Mortgagee and arising from the
following matters, whether any such matters arise before or after foreclosure of
this Mortgage and Security Agreement ( or deed in lieu thereof or similar
actions to the same effect):

(a) Fraud, misrepresentation and waste.


                                       19
<PAGE>   26
(b) Any rents, issues or profits from the Security collected more than one (1)
month in advance of their due dates.

(c) Any misapplication of Loan proceeds, rents, issues or profits, security
deposits and any other payments from tenants or occupants of the Mortgaged
Property (including, without limitation, lease termination fees) insurance
proceeds, condemnation awards, or other sums of a similar nature.

(d) Any wrongful act of the Mortgagor the apparent purpose of which is to
deprive the Mortgagee of any of its Security.

(e) Liability under environmental covenants, conditions and indemnities
contained in the Mortgage.

(f) Rents or other income from the Security which are not first applied to
repayment of the Loan or to the normal operating expenses of the Mortgaged
Property.

(g) Personalty or fixtures removed or allowed to be removed by Mortgagor and not
replaced by items of equal or greater value than the personalty or fixtures so
removed.

(h) An amount equal to the sum of all payments made by Mortgagor to any junior
lienholders during any period in which a monetary default exists under the Loan
Documents.

(i) Failure to pay taxes or assessments prior to delinquency or to pay charges
for labor, materials or other charges which may become liens on any portion of
the Security and any sums expended by Mortgagee in the performance of or
compliance with the obligations of Mortgagor under the Loan Documents,
including, without limitation, sums expended to pay taxes or assessments or
hazard insurance premiums or bills for utilities or other services or products
for the benefit of the Security.

(j) The cost of compliance with all federal, state and local laws and
regulations, as well as the cost of investigating any action or charge
thereunder, and/or damages suffered by Mortgagee as a result of failure of
Mortgagor to pay or comply with any of the foregoing laws and regulations.

(k) Tortious or other acts or omissions of Mortgagor giving rise to claims
against Mortgagee, including, without limitation, claims by tenants for damages
of offsets. 

(l) Attorneys' fees, court costs and other expenses incurred by
Mortgagee in connection with enforcement of Mortgagor's indemnity as set forth
herein.

         This indemnity shall survive any foreclosure of this Mortgage and
Security Agreement, the taking of a deed in lie thereof, or any other discharge
of the obligations of the Mortgagor hereunder or a transfer of the Mortgaged
Property, even if the indebtedness secured hereby is satisfied in full.
Mortgagor agrees that the indemnification granted herein may be enforced by
Mortgagee without resorting to or exhausting any other security or collateral or
without first having recourse to the Note or the Mortgaged Property covered by
this Mortgage and Security Agreement through foreclosure proceedings or
otherwise; provided, however, that nothing herein contained shall prevent
Mortgagee from suing on the Note or foreclosing this Mortgage and Security
Agreement or from exercising any other rights under the Loan Documents.

         24. Use of Proceeds. Mortgagor agrees that no part of the proceeds of
the Loan will be used for the purpose, whether immediate, incidental or
ultimate, or "purchasing" or "carrying" any "margin stock," as such terms are
defined in Regulation G (12 C.F.R.


                                       20
<PAGE>   27
Part 207) of the Board of Governors of the Federal Reserve System or for the
purpose of reducing or retiring any indebtedness which was originally incurred
for any such purpose.

         25. Effect of Sale. Forbearance, Extension. etc. No sale of the
Security, nor forbearance on the part of Mortgagee, and no extension whether
oral or in writing of the time for the payment of the whole or any part of the
debt hereby secured or any other indulgence given by Mortgagee to any persons
other than Mortgagor, shall operate to release or in any manner affect the
original liability of Mortgagor, notice of any such extensions or indulgences
being waived. In the case of foreclosure sale Mortgagee shall be entitled to
retain one percent of the purchase money in addition to the costs, charges and
expenses allowed under the Statutory Power of Sale; and if surplus proceeds are
realized from a foreclosure sale, Mortgagee shall not be liable for any interest
thereon pending distribution of such proceeds by Mortgagee.

         26. No Liability of Mortgagee. Nothing in this instrument shall be
construed as obligating Mortgagee to take any action or incur any liability with
respect to the Security or any business conducted on the Mortgaged Property, and
all options given to Mortgagee are for its exclusive benefit and may be
exercised in its sole discretion.

         27. Severability. If any of the provisions of this instrument is held
to be invalid, illegal or unenforceable by a court of competent jurisdiction,
the other provisions hereof shall be liberally construed in order to effect the
provisions and intent hereof. In the event the payments required to be made
hereunder or pursuant to any other Loan Document, whether such payments are
characterized as interest or otherwise, shall at any time exceed the limits
permitted by any law governing usury or any other law applicable to the Loan
which this Mortgage and Security Agreement secures, all such excess sums paid
by Mortgagor for the period in question shall, without further agreement or
notice between or by any party hereto, be applied to the principal balance of
the Note as a prepayment thereof without premium.

         28. Effect of Consent and Waivers. No consent or waiver, express or
implied, by Mortgagee to or of any default by Mortgagor shall be construed as a
consent or waiver to or of any other default. No waiver of any default or other
indulgence shall be effective unless expressed in writing by Mortgagee.

         29. Notices. Any demand, notice or request by either party to the other
shall be in writing and hand delivered to the party intended to receive the
same or mailed by registered or certified mail, return receipt requested, with a
reference to Loan No. 6516959 GB addressed to that party at the address of such
party set forth at the beginning of this instrument or at such other address as
may be set forth in a notice delivered or mailed as herein provided. Such
demand, notice or request shall be deemed given when so hand delivered, or if so
mailed, when deposited with the U.S. Postal Service according to the postmark of
the U.S. Postal Service.

         30. Successors and Assigns; Miscellaneous. The terms, provisions,
covenants and conditions hereof shall be binding upon Mortgagor and its
successors and assigns and shall inure to the benefit of Mortgagee and its
successors and assigns. All references in this Mortgage and Security Agreement
to Mortgagor and Mortgagee shall be deemed to include all such successors and
assigns, respectively. Whenever used, the singular number shall include the
plural, the plural 


                                       22
<PAGE>   28
the singular, and the use of any gender shall be applicable to all genders. The
captions contained herein are used only as a matter of convenience and are not
to be considered as part of this Mortgage and Security Agreement or to be used
in determining the intent of the parties to it.

         31. Governing Law. This Mortgage and Security Agreement has been
executed and delivered in the Commonwealth of Massachusetts and is to be
construed and enforced according to and governed by the laws of the Commonwealth
of Massachusetts.

         32. Modification Procedure. Neither this Mortgage and Security
Agreement nor any other Loan Document may be modified except by an instrument in
writing executed by both parties to this Mortgage and Security Agreement.

EXECUTED AS A SEALED INSTRUMENT this 30th day of June, 1997.
MORTGAGOR:
BTU International, Inc.

 By:
     Thomas P. Kealy
     Its Vice President
                          COMMONWEALTH OF MASSACHUSETTS
Suffolk, ss.
June 30, 1997

         Then personally appeared the above-named Thomas P. Kealy, Vice
President of BTU International, Inc., and acknowledged the foregoing instrument
to be the free act and deed of the said BTU International, Inc., before me

Notary Public
 My commission expires:


                                       22
<PAGE>   29
Exhibit A

                        Legal Description of the Premises

         That certain parcel of land with all buildings and improvements thereon
situated on the easterly side of Esquire Road in the Town of Billerica, County
of Middlesex, Commonwealth of Massachusetts, and is bounded and described as
follows:

         Beginning at the northwesterly corner of the herein described parcel in
the easterly street line of Esquire Road, which is also the southwesterly corner
of Lot B, as shown on a plan entitled "Subdivision Plan of Land in Billerica,
Mass., Scale: 1" = 50', June 7,1985, prepared for B.T.U. Engineering Corp.,
prepared by Allen & Demurjian, Inc., Engineers & Land Surveyors, Boston, Mass.

         Thence running N-66(Degree)-19'-59" -E bounding northwesterly on
aforesaid Lot B for a distance of six hundred thirty-seven and fifty hundredths
(637.50') feet to Route 3, as shown on 1953 State Highway Layout, for a common
comer with Lots A and B on aforementioned Subdivision Plan;

         Thence running generally southerly along said State Highway Layout
curving to the left along the arc of a curve having a radius of ten thousand two
hundred fifty and no hundredths (10,250.00') feet for an arc distance of five
hundred twenty-seven and seventy-one hundredths (527.71') feet to land now or
formerly belonging to J. Howard & Gertrude Beck, Trustees of Chairmar Realty
Trust for a corner;

         Thence running S-71(Degree)-56'-05"-W for a distance of fifty-five and
seventy-six hundredths (55.76') feet to an angle;

         Thence running S-76-02'47"-W for a distance of eighty-nine and
fifty-one hundredths (89.51') feet to an angle;

         Thence running S-62(Degree)-12'-03-W for a distance of thirty-five and
ninety hundredths (35.90') feet to an angle;

         Thence running S-48(Degree)-26'49"'-W for a distance of thirty-six
and seventy-one hundredths (36.71') feet to an angle;

         Thence running S-41(Degree)48'-03"-W for a distance of ninety-one and
forty-eight hundredths (91.48') feet to an angle;

         Thence running S-37(Degree) -56'-51"-W for a distance of one hundred
twenty-three and eighty-three hundredths (123.83') feet to Esquire Road for a
corner;

         The test six (6) courses bounding southerly on aforesaid Chairmar
Realty Trust land;

         Thence running N-53(Degree)-03'-33-W along Esquire Road for a distance
of one hundred ninety-eight and fifty-two hundredths (198.52') feet to a point
of curve;

         Thence turning and running generally northwesterly along Esquire Road
curving to the right along the arc of a curve having a radius of two hundred
fifty-seven and ninety-seven hundredths (257.97') feet for an arc distance of
one hundred forty-two and five hundredths (142.05') feet to a stone bound for a
point of tangency,

         Thence running N-21(Degree)-30'-34'-W along Esquire Road for a distance
of two hundred ninety and eighty-one hundredths (296.81') feet to the point and
place of beginning. 

         Said parcel contains 304,412 square feet or 6.99 acres.


                                       23
<PAGE>   30
         Being Lot C as shown on Plan entitled "Subdivision Plan of Land in
Billerica Mass. prepared for B.T.U. Engineering Corp. and prepared by Allen &
Demurjian, Inc. dated July, 1985 and recorded with said Deeds on August 26, 1985
in Plan Book 149, Page 109.

         A portion of the above described Lot C is shown as Lot 3 on Land Court
Plan 41191 B filed with the Land Court on March 2, 1992.


                                       24
<PAGE>   31
Exhibit B

Permitted Encumbrances

1.       Easement to Massachusetts Electric Company and New England Telephone
         and Telegraph Company dated April 29, 1975 recorded in Book 2171, Page
         650 and 651.

2.       Easement to Massachusetts Electric Company and New England Telephone
         and Telegraph Company dated October 11, 1979, recorded in Book 2392,
         Page 565 and 566.

3.       Rights of J. Raymond Brown under an Agreement dated October 10, 1979 as
         disclosed in a Deed from Graham Builders, Inc., to BTU Engineering
         Corporation dated December 2, 1979 recorded in Book 2412, Page 273 to
         cut and remove timber.

4.       Rights of Joseph Steams to pass and repass over lot referred to in Land
         Court Case No.41191.

5.       Notice of Variance (Case No. 208), recorded in Book 1990, Page 272.

6.       Terms and provisions of Certificate of Approval by Town of Billerica
         Planning Board recorded in Book 2389, Page 28.

7.       Order of Conditions by Billerica Conservation Commission dated November
         17, 1982 recorded in Book 2581, Page 607 and Book 2574, page 427,
         affected by Certificate of Compliance dated August 14, 1985 and
         recorded on August 26, 1985 as instrument No. 34102.


                                       25