<PAGE>

                                                                     Exhibit 10n

                                                               EXECUTION VERSION



                                     LEASE



                                    BETWEEN


                     APPLIED SCIENCE AND TECHNOLOGY, INC.,
                                     Tenant

                                      AND

                     NINETY INDUSTRIAL WAY WILMINGTON LLC,
                                    Landlord

                                       1
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                               Table of Contents
                               -----------------
<TABLE>
<CAPTION>

                                                                            Page
                                                                            ----
<S>                                                                         <C>
ARTICLE I.  Fundamental Lease Provisions...................................   1
---------   ----------------------------
   1.1.     Reference Subjects.............................................   1
ARTICLE II. Premises and Term..............................................   3
----------  -----------------
   2.1.     Premises.......................................................   3
   2.2.     Acceptance of Premises.........................................   3
   2.3.     Existing Tenant................................................   4
   2.4.     Term...........................................................   4
   2.5.     Options to Extend..............................................   4
ARTICLE III.Tenant Work....................................................   5
----------- -----------
   3.1.     No Landlord's Work.............................................   5
   3.2.     Tenant Work....................................................   5
 3.2.1.     General........................................................   5
 3.2.2.     Construction Documents.........................................   5
 3.2.3.     Performance of Tenant Work.....................................   7
 3.2.4.     Payment for Tenant Work........................................   7
ARTICLE IV. Rent...........................................................   7
----------  ----
 4.1.1.     Annual Base Rent-Initial Term..................................   7
 4.1.2.     Annual Base Rent-Extension Terms...............................   8
 4.1.3.     Method of Payment..............................................   8
 4.1.4.     Net Return to Landlord.........................................   8
 4.1.5.     Additional Rent -- Landlord's Taxes............................   8
 4.1.6.     Landlord's Taxes -- Definition.................................   9
 4.1.7.     Additional Rent - Insurance Expenses...........................  10
 4.1.8.     Additional Rent -- Utilities...................................  10
ARTICLE V.  Maintenance....................................................  10
---------   -----------
   5.1.     Tenant's Maintenance Obligation................................  10
   5.2.     Landlord's Maintenance Obligations.............................  11
ARTICLE VI. Additional Covenants...........................................  12
----------  --------------------
   6.1.     Tenant's Covenants.............................................  12
 6.1.1.     Utilities......................................................  12
 6.1.2.     Maintenance....................................................  12
 6.1.3.     Use and Compliance with Law....................................  12
 6.1.4.     Liens and Encumbrances.........................................  13
 6.1.5.     Indemnity......................................................  13
 6.1.6.     Landlord's Right to Enter; Interruptions. Signage..............  14
 6.1.7.     Personal Property at Tenant's Risk.............................  14
 6.1.8.     Damage. Nuisance. Etc..........................................  14
 6.1.9.     Yield Up.......................................................  15
6.1.10.     Holding Over...................................................  15
6.1.11.     Transfer - Assignment and Subletting...........................  16
   6.2.     Landlord's Covenants; Quiet Enjoyment..........................  19
   6.3.     Interruptions..................................................  19
</TABLE>

                                       i

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<TABLE>

<S>                                                                                    <C>
   6.4.      Real Estate Taxes and Insurance......................................     19
   6.5.      Landlord's Hazardous Materials Responsibilities......................     19
   6.6.      Landlord's Casualty Insurance........................................     20
ARTICLE VII. Insurance; Casualty, Taking..........................................     20
-----------  ---------------------------
   7.1.      Insurance by Landlord................................................     20
   7.1.1.    Public Liability Insurance...........................................     20
   7.2.      Waivers of Subrogation...............................................     21
   7.3.      Damage or Destruction of Premises....................................     21
   7.4.      Eminent Domain.......................................................     22
ARTICLE VIII. Default.............................................................     22
------------  -------
   8.1.      Events of Default....................................................     22
   8.2.      Remedies Cumulative; Jury Waiver.....................................     24
   8.3.      Waivers of Default; Accord and Satisfaction..........................     24
   8.4.      Curing and Enforcement...............................................     25
ARTICLE IX.  Miscellaneous Provisions.............................................     25
----------   ------------------------
   9.1.      Notice...............................................................     25
   9.2.      Limitation of Landlord's Liability...................................     25
   9.3.      Excusable Delay......................................................     26
   9.4.      Applicable Law and Construction......................................     26
   9.5.      Estoppel Certificate.................................................     27
   9.6.      Notice of Lease......................................................     27
   9.7.      Landlord's Default...................................................     27
   9.8.      Brokers..............................................................     27
   9.9.      Intentionally Deleted................................................     28
  9.10.      Tenant as Business Entity............................................     28
  9.11.      Security Deposit.....................................................     28
  9.12.      Financial Reports....................................................     28
  9.13.      Inducement Payment...................................................     29
  9.14.      Special Provision Regarding Letter of Credit.........................     29
ARTICLE X.   Landlord's Financing.................................................     30
---------    --------------------
  10.1.      Subordination and Superiority of Lease...............................     30
  10.2.      Rent Assignment......................................................     30
  10.3.      Other Instruments....................................................     30
  10.4.      Mutual Cost of Enforcement; Interest.................................     31
ARTICLE XI........................................................................     31
----------
  11.1.      Special Provisions Regarding Potential Expansion Space...............     31
ARTICLE XII. Index of Certain Defined Terms.......................................     33
-----------  ------------------------------
</TABLE>

                                      ii
<PAGE>

                                     LEASE
                                     -----


                                  ARTICLE I.
                                  ----------
                         Fundamental Lease Provisions
                         ----------------------------

     1.1.  Reference Subjects. Each reference in this Lease to any of the
           ------------------
following subjects shall incorporate the following information. Other terms are
defined throughout this Lease and are indexed in the last Article.

DATE OF LEASE
EXECUTION:          May 21, 1999

PREMISES:           (i) The entire existing building shown diagrammatically on
                    Exhibit A attached hereto consisting of approximately
                    ---------
                    118,000 rentable square feet (the "Building") and other
                    improvements presently known and numbered as 90 Industrial
                    Way, Wilmington, Massachusetts, and (ii) the Lot.

LOT:                That certain real property located at 90 Industrial Way in
                    Wilmington, Middlesex County, Massachusetts, more
                    particularly described on Exhibit B attached hereto and made
                                              ---------
                    a part hereof, subject to and with the benefit of all
                    present and future easements, rights of way, privileges and
                    appurtenances in connection therewith or thereunto
                    belonging.

LANDLORD:           Ninety Industrial Way Wilmington LLC, a Massachusetts
                    limited liability company

ORIGINAL ADDRESS
OF LANDLORD:        c/o Brownfields Recovery Corp.
                    222 Berkeley Street, 14/th/ Floor
                    Boston, MA 02116

LANDLORD'S AGENT:   Brownfields Recovery Corp.
                    222 Berkeley Street, 14/th/ Floor
                    Boston, MA 02116

TENANT:             Applied Science and Technology, Inc.,
                    a Delaware corporation.

ORIGINAL ADDRESS
OF TENANT:          35 Cabot Road
                    Woburn, MA 01801

                                       1
<PAGE>

INITIAL TERM:       Ten (10) Lease years, plus the Tenant Build Out Period.

COMMENCEMENT
DATE:               April 1, 2000, subject to the provisions of Section 2.3
                    hereof.

EXPIRATION DATE:    The tenth (10"') anniversary of the Rent Commencement Date.

EXTENSION TERMS:    Two Extension Terms of Five Lease years each

ANNUAL BASE RENT -
INITIAL TERM:            Lease Year           Rent Per Annum
                         ----------           --------------
                            1-2                $1,032,500.00
                            3-6                $1,150,500.00
                           7-10                $1,268,500.00

ANNUAL BASE RENT -
EXTENSION TERMS:    Ninety-five percent (95%) of Fair Market Rent as determined
                    pursuant to Section 4.1.2, but not less than the Annual Base
                    Rent payable (i) during the tenth Lease year of the Initial
                    Term (for the first Extension Term), or (ii) during the
                    fifth Lease year of the first Extension Term (for the second
                    Extension Term).

LEASE YEAR:         As defined in Section 4.2.1 hereof.

PARKING SPACES:     All of the existing surface parking currently available on
                    the Premises, to which Tenant shall have exclusive access.
                    Landlord agrees not to restripe the parking lot between the
                    date hereof and the Commencement Date without the prior
                    written consent of Tenant.

PERMITTED USES:     Research, development, manufacturing and distribution of
                    equipment for manufacturing semiconductor devices and other
                    advanced applications or other non-residential uses from
                    time to time permitted by applicable law or ordinance.

PUBLIC LIABILITY
INSURANCE:          $2,000,000 per occurrence/$5,000,000 aggregate (combined
                    single limit) for property damage, bodily injury or death.

RENT
COMMENCEMENT
DATE:               The date which is the later to occur of (i) ninety (90) days
                    following the Commencement Date hereunder, or (ii) July 1,
                    2000.

                                       2
<PAGE>

SECURITY DEPOSIT:   $86,041.67.

TENANT BUILD OUT
PERIOD:             The period of time commencing on the Commencement Date and
                    ending on the date immediately preceding the Rent
                    Commencement Date.

BROKER:             Cushman & Wakefield of Massachusetts, Inc.
                    ("Landlord's Broker")
                    CRF Partners ("Tenant's Broker")


Exhibit A    -   Premises Description
Exhibit B    -   Description of Lot
Exhibit C    -   Tenant Work Insurance Schedule
Exhibit D    -   Method for Determining Fair Market Rent


                                  ARTICLE II.
                                  -----------
                               Premises and Term
                               -----------------

     2.1.  Premises.  Landlord leases the Premises to Tenant and Tenant leases
           --------
the Premises from Landlord, subject to matters of record and matters referred to
below, to which Tenant shall conform and be subject. Subject to reasonable rules
established from time to time by Landlord (of which Tenant shall have been given
not less than thirty days' advance written notice, and which shall be uniformly
enforced by Landlord), Tenant shall also have appurtenant rights to use the
roads, utilities and easements now or hereafter serving the Premises in common
with others to whom Landlord has granted or hereafter may grant rights (Landlord
reserving the right from time to time, with Tenant's consent, which shall not be
unreasonably withheld, to grant and relocate easements necessary or proper for
the efficient operation of the Building). Landlord will not construct any
addition to the Building except at the request of Tenant, and then only upon
terms mutually agreed to by the parties in their sole discretion. Subject to the
provisions of Article III and Article V hereof, Tenant shall have the right to
install antennas and satellite dishes on the roof of the building provided such
installations are made in accordance with all applicable laws, rules and
regulations and in such a manner as will not void any roof warranty or otherwise
adversely affect the structural integrity of the Building.

     2.2.  Acceptance of Premises.  Landlord shall have no obligation or risk
           ----------------------
with respect to the condition of the Premises other than as expressly set forth
in this Lease, including Article III (and, in the case of casualty or taking, in
Sections 7.3 and 7.4). Tenant acknowledges that it has inspected the Premises
and agrees to accept the Premises in their current "AS IS" condition, subject to
reasonable wear and tear by AGFA Corporation or its successors or assigns (the
"Existing Tenant"). Tenant's occupancy shall be deemed an acknowledgment that
the condition of the Premises is satisfactory and that Landlord has fulfilled
all obligations with respect to such condition, subject to any "punchlist items"
of which Tenant notifies Landlord in writing within thirty (30) days following
Landlord's delivery of the Premises to Tenant. Tenant further acknowledges that,
except as expressly set forth herein, neither Landlord nor any person acting

                                       3
<PAGE>

under Landlord has made or implied any representations or warranties concerning
the Premises, their condition or this Lease.

     2.3.  Existing Tenant.  Landlord and Tenant acknowledge that the Premises
           ---------------
are currently occupied by the Existing Tenant. Landlord warrants to Tenant that
the Existing Tenant has and shall have no right to occupy any or all of the
Premises after February 5, 2000, and Landlord shall not make, amend or modify
any lease or agreement with the Existing Tenant pursuant to which the Existing
Tenant's rights to so occupy the Premises are extended beyond such date.
Landlord agrees to deliver possession of the Premises to Tenant not later than
April 1, 2000, and Landlord shall coordinate with the Existing Tenant regarding
the removal of Existing Tenant's fixtures, equipment and improvements
(including, without limitation, telephones, cubicle furniture, computer
equipment and the Halon fire suppression system) following the expiration or
sooner termination of the Existing Tenant's occupancy. The failure of Landlord
to deliver the entire Premises to the Tenant by April 1, 2000 shall not be a
default of the Landlord under this Lease nor give rise to any rights and
remedies on the Tenant's part, so long as Landlord shall promptly initiate and
thereafter diligently pursue to completion a summary process action to recover
possession of the Premises. If by May 1, 2000, the Landlord has failed to so
deliver the entire Premises to the Tenant, then for each day after May 1 that
such failure continues, and as its sole remedy therefor, Tenant shall be
entitled to one (1) day's free occupancy after the Rent Commencement Date. If by
August 1, 2000 the Landlord has still failed to so deliver the entire Premises
to the Tenant, then as its sole remedy therefor the Tenant may terminate this
Lease by notice thereof to the Landlord, whereupon this Lease shall terminate
and be without further force or effect, except that Landlord shall reimburse
Tenant for Tenant's actual and reasonable costs and expenses (including without
limitation reasonable attorneys' fees) of entering into this Lease not to exceed
$7,500 in the aggregate.

     2.4.  Term.  This Lease will be for an Initial Term beginning on the
           ----
Commencement Date and ending on the Expiration Date set forth in Section 1.1
provided that if Landlord delivers possession of the Premises to Tenant prior to
April 1, 2000, then the Commencement Date shall occur upon such delivery and all
Additional Rent payable by Tenant under Article IV hereof shall be paid pro-rata
from and after the date of such delivery. The parties hereto agree, upon demand
of the other, to execute one or more supplemental instruments expressing the
Commencement Date and the Rent Commencement Date hereunder once the same have
been determined, but the failure to do so shall have no effect on either such
Date.

     2.5.  Options to Extend.  At the Tenant's election, this Lease may be
           -----------------
extended for two (2) successive Extension Terms set forth in Section 1.1 by
written notice given at least 12 months prior to the end of the then expiring
term, time being of the essence to such exercise, so long as at the time of such
notice and at the beginning of the applicable Extension Term there exists no
Event of Default hereunder. All references to the Term shall mean the Initial
Term as it may be extended by any Extension Term.

                                       4
<PAGE>

                                 ARTICLE III.
                                 ------------
                                  Tenant Work
                                  -----------

     3.1.  No Landlord's Work.  Landlord will not be required to provide any
           ------------------
work or improvements to the Premises to prepare the same for Tenant's occupancy.
Tenant acknowledges that, as of the date hereof, it has had the full opportunity
to inspect the Premises with engineering consultants.

     3.2.  Tenant Work.
           -----------

           3.2.1.  General.  Tenant shall be responsible for performing and
                   -------
paying for all Tenant Work. "Tenant Work" shall mean such work, including
demolition, improvements, additions and alterations, in or to the Premises as
Tenant may in its sole discretion deem necessary for its business. Without
limiting the generality of the foregoing, Tenant Work shall specifically include
all attached carpeting, all signs visible from the exterior of the Premises
(which signage shall conform to all applicable bylaws and codes and shall be
mutually agreed upon with Landlord, which agreement Landlord will not
unreasonably withhold), and any change in the exterior appearance of the windows
in the Premises (including shades, curtains and the like). All Tenant Work
costing in excess of $250,000 shall be subject to Landlord's prior written
approval not to be unreasonably withheld or delayed, and (subject to section
9.13) shall be arranged and paid for by Tenant as provided herein. Tenant shall
neither propose nor effect any Tenant Work (i) which adversely affects any
structural component of the Building (including, without limitation, exterior
walls, exterior windows, core walls, roofs, or floor slabs) or changes to any
exterior architectural features, (ii) which adversely affects the electrical or
mechanical components or systems of the Building, or (iii) which adversely
affects in any respect other property than the Premises.

           3.2.2.  Construction Documents.  No Tenant Work requiring
                   ----------------------
Landlord's approval shall be effected except in accordance with complete
construction drawings and specifications ("Construction Documents") approved in
advance by Landlord, which approval shall not be unreasonably withheld. If
Landlord does not disapprove any Construction Documents for Tenant Work
submitted within twenty (20) days after submission, then the same shall be
deemed approved at the end of such period. At the time of granting its approval
of any Tenant Work, Landlord shall specify which, if any, of such Work Tenant
will be required to remove upon the expiration or earlier termination of the
Term. The Construction Documents shall be prepared by an architect ("Tenant's
Architect") experienced in the construction of tenant space improvements in
buildings in the greater Boston area. Tenant shall be solely responsible for the
liabilities of and expenses of all architectural and engineering services
relating to Tenant Work and for the adequacy, accuracy, and completeness of the
Construction Documents approved by Landlord, even if Tenant's Architect has been
otherwise engaged by Landlord in connection with the Building. The Construction
Documents shall set forth in detail the requirements for construction of the
Tenant Work (including all architectural, mechanical, electrical and structural
drawings and detailed specifications), shall be fully coordinated with one
another and with field conditions as they exist in the Premises, and shall show
all work necessary to complete the Tenant Work including all cutting, fitting,
and patching and all connections to the mechanical and electrical systems and
components of the Building. Submission of the Construction Documents to

                                       5
<PAGE>

Landlord for approval shall be deemed a covenant by Tenant (unless Tenant
furnishes a certificate of Tenant's Architect substantially to the same effect)
that all Tenant Work described in the Construction Documents (i) complies with
all applicable laws, regulations and building codes, (ii) does not in any manner
adversely affect any structural component of the Building (including, without
limitation, exterior walls, exterior windows, core walls, roofs or floor slabs),
(iii) does not in any manner adversely affect the electrical and mechanical
components and systems of the Building, (iv) does not affect any property other
than the Premises, and (v) conforms to floor loading limits. Landlord's approval
of Construction Documents shall only signify Landlord's consent to the Tenant
Work shown thereon and shall not result in any responsibility of Landlord
concerning compliance of the Tenant Work with laws, regulations, or codes,
coordination of any aspect of the Tenant Work with any other aspect of the
Tenant Work or any component or system of the Building, or the feasibility of
constructing the Tenant Work without damage or harm to the Building, all of
which shall be the sole responsibility of Tenant.

                                       6
<PAGE>

          3.2.3.  Performance of Tenant Work.  In the case of (a) any
                  --------------------------
Tenant Work requiring Landlord's approval of such Work, or (b) any Tenant Work
affecting any structural, mechanical or electrical systems of the Building, the
identity of any general contractor (including any employee or agent of Tenant
acting as a general contractor) performing any Tenant Work ("Tenant Contractor")
shall be subject to Landlord's prior approval which approval shall not be
unreasonably withheld. Once any Tenant Contractor has been approved, then the
same may thereafter be used by Tenant until Landlord reasonably notification
notifies Tenant that such Tenant Contractor is no longer approved. Tenant shall
procure all necessary governmental permits, licenses and approvals before
undertaking any Tenant Work. Tenant shall perform all Tenant Work at Tenant's
risk in compliance with all applicable laws, codes and regulations and in a good
and workmanlike manner employing new materials of good quality and producing a
result reasonably comparable in quality to the other parts of the Premises. When
any Tenant Work is in progress Tenant shall cause to be maintained insurance as
described in the Tenant Work Insurance Schedule attached hereto as Exhibit C and
such other insurance as may be required by Landlord covering any additional
hazards due to such Work for the benefit of Landlord and in any event naming
Landlord as an additional insured thereunder. It shall be a condition of
Landlord's approval of any Tenant Work that certificates of such insurance
issued by responsible insurance companies qualified to do business in
Massachusetts and carrying an A.M. Best (or successor rating agency) rating of
A-VII or better shall have been delivered to Landlord, that Tenant has provided
Tenant's certification of the insurable value of the work in question for
casualty insurance purposes, and that all of the other conditions of the Lease
have been satisfied. To the extent outside expertise is reasonably required by
Landlord, Tenant shall reimburse Landlord's actual and reasonable third party
expenses incurred in connection with Landlord's review of any proposed Tenant
Work and inspecting installation of the same. At all times while performing
Tenant Work, Tenant shall require any Tenant Contractor to comply with all
applicable laws, regulations and permits relating to such work. Each Tenant
Contractor shall be required by Tenant to agree to indemnify and hold the
Indemnitees harmless from any claim, loss or expense arising in whole or in part
out of any negligent or wrongful act or neglect committed by such person while
in the Building, to the same extent as Tenant has so agreed in this Lease, the
indemnities of Tenant and Tenant's Contractor to be joint and several.

          3.2.4.  Payment for Tenant Work.  Tenant shall pay as the same becomes
                  -----------------------
due, the entire cost of all Tenant Work so that the Premises shall always be
free of liens for labor or materials. If any lien relating to the furnishing of
labor or materials is filed against the Premises or any part thereof which is
claimed to be attributable to Tenant, its agents, employees or contractors or
others acting under Tenant, then Tenant shall promptly discharge the same by
payment or filing any necessary bond within 30 days after Tenant has notice from
any source of such lien.

                                  ARTICLE IV.
                                  -----------
                                     Rent
                                     ----

          4.1.1.  Annual Base Rent-Initial Term.  Annual Base Rent during
                  -----------------------------
the Initial Term will be as set forth in Section 1.1. Notwithstanding the
foregoing, Annual Base Rent shall not

                                       7
<PAGE>

begin to accrue or be payable until the Rent Commencement Date but all
additional rent and other charges payable by Tenant under the terms of this
Lease shall begin to accrue and be payable on the Commencement Date.

          4.1.2.  Annual Base Rent-Extension Terms.  If the Term is
                  --------------------------------
extended for the first Extension Term (or the second Extension Term, as
applicable), then Annual Base Rent will be as set forth in Section 1.1. Fair
Market Rent for the Premises during such Extension Term for the purpose of
calculating Annual Base Rent -- Extension Term under Section 1.1 shall be
ascertained as set forth on Exhibit D attached hereto and made a part hereof.

          4.2.1.  Method of Payment.  Tenant agrees to pay the Annual Base
                  -----------------
Rent to Landlord in advance in equal monthly installments by the first of each
calendar month during the Term. Except as hereafter provided with respect to the
first Lease year, the term "Lease year" shall mean the twelve-month period
following the Rent Commencement Date (unless the Rent Commencement Date is other
than the first day of a month, in which case "Lease year" shall mean the twelve-
month period following the initial partial month). The first Lease year shall
commence on the Commencement Date and expire on the day immediately preceding
the first anniversary of the Rent Commencement Date. Tenant shall make ratable
payment of Annual Base Rent for any period of less than a month at the beginning
or end of the Term. All payments of Annual Base Rent, additional rent and other
sums due shall be paid in current U.S. exchange by check, at the Original
Address of Landlord or such other place as Landlord may from time to time direct
by at least thirty (30) days' written notice, without notice, demand, set-off or
other deduction.

          4.2.2.  Net Return to Landlord.  It is intended that Annual Base
                  ----------------------
Rent payable hereunder shall be a net return to Landlord throughout the Term,
and all provisions hereof shall be construed in terms of such intent. Without
limiting the foregoing, Tenant's obligations hereunder, including the obligation
to pay all rent, shall not be discharged, abated, reduced or otherwise affected
by any law now or hereafter applicable to the Premises, or any other restriction
on Tenant's use, or, except as expressly provided in Article VII, by any damage
or destruction of the Premises or by any taking of the Premises or any part
thereof by condemnation or otherwise, or by any prohibition, limitation,
restriction, prevention or interference of tenant's use, occupancy or enjoyment
of the Premises by any person, and Tenant waives all rights now or hereafter
existing (other than those rights expressly set forth in this Lease) to
terminate, rescind, quit or surrender this Lease or the Premises or any part
thereof, or to assert any defense in the nature of constructive eviction to any
action seeking to recover rent except for any compulsory counterclaims. Subject
to Section 9.2, however, Tenant shall have the right to obtain judgments from
Landlord for direct monetary damages occasioned by Landlord's breach of its
Lease obligations or otherwise enforce its rights hereunder.

          4.3.1.  Additional Rent -- Landlord's Taxes.  Tenant covenants
                  -----------------------------------
and agrees to pay to Landlord, as additional rent, all of Landlord's Taxes
(hereafter defined) for each fiscal tax

                                       8
<PAGE>

period, or ratable portion thereof, included in the Lease Term, each such
payment to be made not later than ten (10) days prior to the date such taxes are
due (or, if later, five (5) business days after receipt of Landlord's tax bill).
Landlord shall furnish to Tenant copies of all bills relating to any Landlord's
Taxes within fifteen (15) days after Landlord's receipt thereof. Landlord and
Tenant agree to use good faith efforts to cause the municipal taxing authority
to issue the tax bill for the Premises directly to Tenant during the term of
this Lease, and if the same is accomplished Tenant agrees to furnish Landlord
with a copy thereof within fifteen (15) days after receipt, and Tenant shall
make each payment thereunder not later than ten (10) days prior to the date such
taxes are due. In the event that Landlord's institutional first mortgagee
requires that Landlord pay Landlord's Taxes to the mortgagee on a monthly basis,
Tenant shall make such payments to the mortgagee as required, on the conditions
that (i) such mortgagee shall not use such funds for any purpose other than
payment of Landlord's Taxes, and (ii) evidence of payment will be sent to
Tenant. Without implying that other covenants do not survive, the covenants of
this Section shall survive the Term.

          4.3.2.  Landlord's Taxes -- Definition.  "Landlord's Taxes" shall
                  ------------------------------
mean all taxes, assessments, betterments, excises, user fees and all other
governmental charges and fees of any kind or nature, or impositions made in
connection with the provision of governmental services or improvements of
benefit to the Premises (including any so-called linkage payments payable under
a legally binding written agreement executed and delivered prior to the date
hereof), and all penalties and interest thereon (to the extent due to Tenant's
failure to make timely payments on account of Landlord's taxes), actually
assessed or imposed against the Premises (including without limitation any
personal property taxes levied on such property or on fixtures or equipment
owned by Tenant and used in connection therewith), or upon Landlord by virtue of
its ownership thereof, other than a federal or state income tax of general
application and other than any transfer, inheritance, succession, estate or gift
tax. If during the Term the present system of ad valorem taxation of property
shall be changed so that, in lieu of or in addition to the whole or any part of
such ad valorem tax there shall be assessed, levied or imposed on such property
or Premises or on Landlord any kind or nature of federal, state, county,
municipal or other governmental capital levy, sales, franchise, excise or
similar tax, assessment, levy charge or fee (as distinct from the federal and
state income tax of the kind in effect on the Commencement Date and excluding
any transfer, inheritance, succession, estate or gift tax) measured by or based
in whole or in part upon Building valuation, mortgage valuation, rents or any
other incidents, benefits or measures of real property or real property
operations which is used directly or indirectly to fund the same kinds of goods
and services as are funded by the present property tax, then any and all of such
taxes, assessments, levies, charges and fees shall be included within the term
Landlord's Taxes.

          During the Term of this Lease, Tenant shall have the exclusive right
to apply for and prosecute any tax abatement or appeal applications or
proceedings (other than those pending as of the date hereof, of which Landlord
has advised Tenant). Tenant shall advise Landlord of any such proceeding
initiated by Tenant, and shall forward to Landlord copies of pleadings and
filings. Such proceedings shall not affect Tenant's obligations to pay
Landlord's Taxes hereunder, except that to the extent permitted by law, Tenant
may withhold payment (or make payments under protest) pending resolution, so
long as (i) Landlord is not exposed to civil or

                                       9
<PAGE>

criminal liability, and (ii) Landlord's interest in the Building is not
subjected to further lien or encumbrance. Tenant shall pay all costs and
expenses of such appeal proceedings. Landlord shall cooperate in such endeavor,
provided that Tenant pays Landlord's actual and reasonable out-of-pocket
expenses in connection with such cooperation.

          4.4.1  Additional Rent - Insurance Expenses.  Tenant covenants
                 -----------------------------------
and agrees to pay to Landlord, as additional rent, the premiums on fire,
casualty, rent loss, liability and other insurance maintained by Landlord for
and with respect to the Premises and/or the Lot, and such payment shall be
prorated for any partial premium year. Such additional rent shall be payable in
monthly installments on the first day of each month in advance, based on amounts
reasonably estimated by Landlord and with a final payment adjustment between the
parties within 14 days after Landlord provides Tenant a statement of such costs
and expenses for Landlord's most recent fiscal year.

          4.5    Additional Rent -- Utilities.  Tenant shall pay directly to
                 ----------------------------
the applicable utility companies all charges for water, sewer, gas, electricity,
telephone and other utilities or services used or consumed on the Premises
during the Term of this Lease, whether called charge, tax, assessment, fee or
otherwise, including, without limitation, water and sewer use charges and taxes,
if any, all such actual charges to be paid as the same from time to time become
due. If Tenant is not billed directly by the applicable utility company for any
such utilities or services, Tenant shall from time to time, within thirty (30)
days after receipt of Landlord's invoice therefore, pay to Landlord the total of
such charges assessed against the Premises by such utility company. It is
understood and agreed that Tenant shall make its own arrangements for such
utilities and that Landlord shall be under no obligation to furnish any
utilities to the Premises and shall not be liable for any interruption or
failure in the supply of any such utilities to the Premises. Notwithstanding any
of the foregoing to the contrary, Tenant shall pay for any utilities used by
Tenant prior to the Rent Commencement Date.

                                  ARTICLE V.
                                  ----------
                                  Maintenance
                                  -----------

          5.1.  Tenant's Maintenance Obligation. Tenant shall, from and after
                -------------------------------
the Commencement Date until the end of the Term and any extension thereof,
maintain the Premises in as good condition and repair as the Premises are at the
Commencement Date, reasonable wear and tear and damage to the Premises caused by
Landlord's default hereunder, fire and casualty or by eminent domain, excepted.
With the exception of Landlord's continuing obligation to maintain the
Building's roof and Building Structural Elements as set forth in Section 5.2,
Tenant shall be responsible to perform all maintenance and repairs necessary to
maintain in good order, condition and repair the Premises and all "Building
Systems" (as hereinafter defined), at Tenant's sole cost and expense with no
contribution from Landlord. Without limiting the foregoing (and except to the
extent that the need therefor arises from the negligent or wrongful act or
omission of Landlord or its agents or contractors), Tenant shall maintain,
repair and replace, as necessary, all Building Systems. In addition, Tenant
shall make all routine and non-

                                      10
<PAGE>

structural replacements, alterations and improvements to the Premises which are
required by any law, statute, code, ordinance, bylaw, rule or regulation of any
governmental authority first becoming effective after the date hereof. As used
herein, the term "Building Systems" shall mean, collectively, the plumbing,
sprinkler, fire suppression, heating, ventilating and air conditioning,
electrical and mechanical lines and equipment associated therewith, located
within and serving the Premises.

          During the Term, Tenant shall replace, as necessary, all Building
Systems ("System Replacement Work") and the cost of all System Replacement Work
performed by Tenant shall initially be paid by Tenant, subject to reimbursement
by Landlord for a portion of such cost as provided in the following provisions
of this paragraph. With respect to any System Replacement Work performed by
Tenant pursuant to the preceding provisions of this paragraph, upon the earlier
to occur of (x) the date which is eleven (11) months prior to the expiration of
the term of this Lease (as the same may be extended in accordance with the terms
hereof), or (y) the earlier termination of this Lease, Landlord shall reimburse
to Tenant a percentage of the cost thereof, which percentage shall be the
decimal equivalent of the fraction the numerator of which is the number of years
(or fraction thereof) remaining in the useful life of the System Replacement
Work in question at the time of such expiration or termination and the
denominator of which is the full useful life of the System Replacement Work in
question, (expressed in a number of years or fraction thereof), which useful
life shall be determined by reference to the shortest useful life permissible
under federal income tax regulations. Any amount to be reimbursed by Landlord to
Tenant pursuant to the provisions of this paragraph shall be paid to Tenant
within forty-five (45) days after receipt by Landlord of a statement of the
amount to be paid which statement shall provide a detailed explanation of the
calculation of the amount to be paid by Landlord (including, without limitation,
the total cost of the work performed and Tenant's determination of the useful
life of the System Replacement Work in question).

          Tenant shall maintain in reasonably good condition all lawns and
planted areas on the Lot. Tenant shall also provide snow plowing of parking
areas, walks and driveways within the Lot as reasonably necessary or
appropriate.

     5.2. Landlord's Maintenance Obligations. During the Term, Landlord shall
          ----------------------------------
have a continuing obligation to maintain in good order, condition and repair the
roof of the Building and the Building Structural Elements (as hereinafter
defined) in good order, condition and repair and in accordance with all
applicable laws, codes and regulations.

          In the event that Tenant damages any portion of the Building's roof or
Building Structural Elements or Building Systems, then Tenant shall be
responsible for any maintenance required as a result of such disturbance by
Tenant. As used herein, the phrase "Building Structural Elements" shall mean the
exterior and interior structures of the Building, including the exterior walls,
bearing walls, support beams, foundation, columns, exterior doors and windows
and lateral support to the Building. Notwithstanding any of the foregoing to the
contrary, Landlord shall have no obligation to maintain any Building Structural
Elements or to contribute toward the cost of replacing any Building Systems
which were installed by Tenant, or up-graded by Tenant or otherwise modified by
Tenant. In addition, notwithstanding anything contained

                                      11
<PAGE>

herein to the contrary, Landlord shall have no obligation with respect to any
repairs, replacements, additions, alterations and improvements to the roof or
Building Structural Elements or Building Systems required by any law, statute
code, ordinance, by-law, rule or regulation of any governmental authority due to
Tenant's particular use or manner of use of the Premises, which would not
otherwise be required and necessary for the average office, manufacturing or
research and development business.

                                  ARTICLE VI.
                                  -----------
                             Additional Covenants
                             --------------------

     6.1. Tenant's Covenants.  Tenant agrees during the Term and such further
          ------------------
time as Tenant (or any person acting under it) occupies any part of the Premises
to perform the following, all at Tenant's cost.

          6.1.1.  Utilities.  Tenant shall arrange, provide and pay
                  ---------
directly for all water, sewer, oil, gas, electricity and other energy or utility
services which serve the Premises and deposits or bonds in connection therewith.
Landlord shall not be liable for (nor suffer any reduction in any rent on
account of) any interruption or failure in the supply of any utility services.

          6.1.2.  Maintenance.  Subject only to Landlord's obligation in
                  -----------
Section 5.2 hereof, Tenant shall maintain, repair and keep in compliance with
all governmental requirements the Premises and all improvements and
appurtenances and all utilities, facilities, installations and equipment used in
connection therewith.

          6.1.3.  Use and Compliance with Law.  Tenant shall occupy the
                  ---------------------------
Premises for no purpose other than the Permitted Uses, and only as and to the
extent permitted under present and future laws, ordinances and bylaws and all
regulations thereunder (including the Americans With Disabilities Act of 1990),
permits, orders and conditions of any special permits or other governmental
approvals ("Laws"). Tenant shall also keep the Premises equipped with
appropriate safety appliances and comply with all requirements of insurance
inspection or rating bureaus applicable from time to time to the particular
manner of use (as opposed to the average manufacturing, research and development
and offices uses) being made of the Premises or to Tenant particularly (as
opposed to other tenants generally), or both, foreseen or unforeseen, and
whether or not the same necessitate structural or other extraordinary changes or
improvements to the Premises or interfere with Tenant's use. Tenant may
diligently contest any such laws so long as (a) such contest is made in good
faith and (b) any such contest does not expose Landlord to any criminal
liability or civil penalty, result in the possibility of any lien being imposed
upon the Premises, or subject Landlord to any civil liability beyond the amount
of any bond or cash collateral furnished by Tenant in the amount of any such
liability. Tenant shall procure all appropriate approvals, licenses and permits,
in each case promptly giving Landlord true and

                                      12
<PAGE>

complete copies of the same and all applications therefor. It is intended that
Tenant bear the sole risk of all present or future laws affecting the Premises
applicable to the particular manner of use (as opposed to laws generally
applicable to manufacturing, research and development and offices uses) being
made of the Premises and Landlord shall not be liable for, nor suffer any
reduction in any rent on account of, the enforcement of such laws, it being
understood and agreed that the provisions of the parenthetical in this sentence
shall not in any way limit Tenant's responsibilities or obligations set forth in
Section 6.1.8 of this Lease.

          6.1.4.  Liens and Encumbrances.  Tenant shall keep the Premises
                  ----------------------
(and Landlord's interest therein) and Tenant's leasehold (and Tenant's interest
therein) free of, and shall within one month discharge or bond any perfected
lien, security interest or other encumbrance which arises as a result of any act
or omission of Tenant or persons acting under Tenant.

          6.1.5.  Indemnity.  (a) Subject to the rights expressly reserved
                  ----------
to Landlord, Tenant shall assume exclusive control of the Premises, the parking
areas available for Tenant's exclusive use and all sidewalks, walkways and
driveways on the Lot and used in connection with the foregoing, and, except as
provided below, Tenant shall bear the sole risk of all related tort liabilities.
Except to the extent arising from the negligent or wrongful act or omission of
any Landlord Indemnitee, or any person acting under any Landlord Indemnitee
(other than Tenant and Tenant Indemnitees) Tenant shall indemnify, save harmless
and defend Landlord and its partners, members, managers, mortgagees, agents and
employees ("Landlord Indemnitees") from all liability, claim, damage, cost or
loss (including reasonable fees of legal counsel of the Tenant's (or any insurer
assuming liability) choice against whom Landlord makes no reasonable objection)
arising in whole or in part out of, or in any manner connected with (i) any
injury, loss, theft or damage to any person or property while on or about the
Premises, or (ii) bodily injury or property damage resulting from any condition
of the Premises and/or the possession and use thereof or any activity permitted
or suffered thereon during the Term (including hazardous materials or hazardous
materials activities), or (iii) bodily injury or property damage resulting from
any breach of any covenant, representation or certification contained in this
Lease by Tenant or persons acting under Tenant, or (iv) bodily injury or
property damage resulting from any negligent or wrongful act or omission
anywhere by Tenant or persons acting under Tenant.

     (b)  Except to the extent arising from the negligent or wrongful act or
omission of any Tenant Indemnitee, or any person acting under any Tenant
Indemnitee, Landlord shall indemnify, save harmless and defend Tenant and those
claiming by, through or under Tenant ("Tenant Indemnitees") from all liability,
claim, damage, cost or loss (including reasonable fees of legal counsel of the
Landlord's (or any insurer assuming liability) choice against whom Tenant makes
no reasonable objection) actually and reasonably suffered or incurred and
arising in whole or in part out of, or in any manner connected with (i) any
bodily injury or property damage resulting from any breach of any covenant,
representation or certification contained in this Lease by Landlord or its
agents, contractors and employees, or (ii) any bodily injury or property damage
resulting from any negligent or wrongful act or omission anywhere by Landlord or
Landlord's agents, contractors or employees.

                                      13
<PAGE>

          6.1.6.  Landlord's Right to Enter; Interruptions. Signage. Landlord
                  -------------------------------------------------
and persons acting under Landlord may upon such notice and in such as is
reasonable under the circumstance (being at least 24 hours except in the case of
an emergency) enter the Premises during business hours (and in case of emergency
at any time) in exercise of any rights reserved to Landlord, or to inspect the
Premises, or to take measurements of the Premises, or to secure or protect the
Premises; and similarly at any time may show the Premises to prospective
purchasers and lenders, and during the last 12 months of the Term prospective
tenants, and during the last 6 months of the Term may keep affixed in suitable
places reasonably approved by Tenant notices for letting. In addition, Landlord
may affix at its expense a suitable sign reasonably acceptable to Tenant at each
main entrance to the Premises identifying the Premises as property owned by
Landlord. Except in case of emergency, Landlord's entering the Premises shall be
subject to reasonable security conditions, if any, set forth in a notice by
Tenant to Landlord. Landlord's rights will be exercised in a manner which will
not unreasonably interfere with Tenant's operations and will be consistent with
Tenant's reasonable security measures.


          6.1.7.  Personal Property at Tenant's Risk.  All personal property of
                  ----------------------------------
any person which is located on or near the Premises shall be at the sole risk of
Tenant. Landlord shall not be liable for any loss or damage to persons or
property resulting from any accident, theft, vandalism or other occurrence on
the Premises, including damage resulting from water, wind, ice, steam,
explosion, fire, smoke, chemicals, the rising of water or leaking or bursting of
pipes or sprinklers, defects, structural or non-structural failure, or any other
cause except to the extent such loss or damage is caused solely and directly by
Landlord's negligence.


          6.1.8.  Damage. Nuisance. Etc.  Tenant shall not itself, or permit or
                  ---------------------
suffer persons acting under Tenant to, either with or without negligence,
injure, overload, deface or damage Landlord's property, the Premises or any part
or component thereof commit any nuisance; permit the emission, discharge,
release or other escape of any oil or petroleum products, asbestos,
polychlorinated biphenyls or any biologically or chemically active or other
hazardous or toxic materials, substances or wastes whether in solid, liquid or
gaseous state (collectively, "hazardous materials") so as to impregnate, impair
or in any manner affect, even temporarily, any element or part of the Premises
or the property or person of others, or allow the storage, generation, disposal
or use of such materials (collectively "hazardous materials activities") in any
manner prohibited by law; nor shall Tenant permit to be brought onto the
Premises any such materials except to use in the ordinary course of Tenant's
business or permit any waste of the Premises. If Landlord reasonably believes
(after appropriate inquiry) that a release may have occurred or a threat of
release exists on or about the Premises by reason of any act or omission of
Tenant or persons acting under Tenant or Tenant's hazardous materials activities
do not conform to all laws, then Landlord may, but need not, perform appropriate
testing in a commercially reasonable manner and if such testing reveals that
Tenant has violated the foregoing provisions, the reasonable costs thereof shall
be reimbursed to Landlord by Tenant upon demand as additional rent. Without
limitation, hazardous materials shall include all substances or materials, in
whatever form, described in the Comprehensive Environmental Response,
Compensation and Liability Act of 1980, as amended, 42 U.S.C. 9601 et seq.; in
the Resource Conservation and Recovery Act, as amended, 42 U.S.C. 6901 et seq.;
in the Hazardous Materials Transportation Act; in the

                                      14
<PAGE>

Massachusetts Hazardous Waste Management Act, as amended, M.G.L. Chapter 21C,
and the Massachusetts Oil and Hazardous Material Release Prevention Act, as
amended, M.G.L. Chapter 21E and all other laws governing similar matters as they
may be amended from time to time. In addition, in connection with any sale or
financing by Landlord, Tenant shall execute reasonable and customary affidavits,
representations and the like from time to time at Landlord's request concerning
Tenant's best knowledge and belief (but without duty of inquiry) regarding the
presence or absence of hazardous materials on the Premises provided that
Landlord shall reimburse Tenant for any reasonable third party costs actually
incurred in connection therewith (to the extent Tenant would not be obligated to
execute and deliver such instrument in the absence of such sale or financing),
and also provided that Tenant shall in no event be required to incur or assume
additional liability or obligation in so doing which Tenant does not already
have under the terms of this Lease or under law. In all events and without
limitation, Tenant assumes liability pursuant to Section 6.1.5 for any personal
injury or property damage (including loss of use) or any other cost or expense
resulting in claims arising out of the discharge, dispersal, release or escape
of hazardous materials or any pollutants or contaminants whatsoever occurring on
the Premises by reason of any act of omission of Tenant or persons acting under
Tenant whether before or during the Term of this Lease, and for so long
thereafter as Tenant or persons acting under Tenant remain in occupancy of any
portion of the Premises, and Tenant shall indemnify Indemnitees in the manner
elsewhere provided in Section 6.1.5 of this Lease with respect to hazardous
materials and hazardous materials activities (and for these purposes the costs
and loss indemnified shall include any costs of investigation of site
conditions, any cleanup, remediation, removal or restoration work and any lost
rents). Without limiting the foregoing, Tenant shall promptly take all actions
at its sole expense as are necessary to remediate the conditions caused by such
materials in accordance with and to the extent required by law; provided that
such actions are undertaken in accordance with all applicable laws, rules and
regulations and accepted industry practices. The provisions of this Section
shall survive the Term.

          6.1.9.   Yield Up.  At the termination of the Term, Tenant (and all
                   --------
persons claiming through Tenant) shall without the necessity of notice surrender
the Premises and all keys (or lock combinations) to the Premises; and shall
remove all Tenant Work which Landlord notified Tenant it would be required to
remove at the time it approved such Work (excluding partitions, floor coverings
and wall coverings), and all trade fixtures and personal property whether or not
bolted or otherwise attached, and all of Tenant's signs wherever located, in
each case repairing damage which results from such removal and restoring the
Premises to substantially the same tenantable condition of the Premises on the
Commencement Date. Tenant shall yield up the Premises broom-clean, reasonable
wear, damage by casualty or taking or damage by Landlord's negligence or failure
to perform hereunder excepted. Any property not so removed shall be deemed
abandoned, shall at once become the property of Landlord, and may be disposed of
in such manner as Landlord shall see fit; and Tenant shall pay the cost of
removal and disposal to Landlord upon demand.

          6.1.10.  Holding Over.  If Tenant (or anyone claiming through Tenant)
                   ------------
shall remain in possession of the Premises or any part thereof after the
expiration or termination of the

                                      15
<PAGE>

Term without a written agreement executed by Landlord, then without limit to
Landlord's other rights and remedies the person remaining in possession shall be
deemed a tenant at sufferance, and Tenant shall thereafter pay monthly rent (pro
rated for such portion, of any partial month as Tenant or such party shall
remain in possession) at a rate equal to two times the amount payable as Annual
Base Rent for the then expiring Lease year, and with all additional rent also
payable as provided in this Lease; and after Landlord's acceptance of the full
amount of such rent for the first month following the Term the person remaining
in possession shall be deemed a tenant at sufferance at such rent but shall be
otherwise subject to all of the provisions of this Lease. In any case, Tenant
shall remain liable to Landlord for all actual damages resulting from such
breach with the amount of any rent accepted by Landlord on account of the
holding over considered in mitigation of such damages.

          6.1.11.  Transfer - Assignment and Subletting.  Except for Permitted
                   ------------------------------------
Transfers (hereinafter defined), Tenant shall not assign this Lease, or sublet
or license the Premises or any portion thereof or permit the occupancy of all or
any portion of the Premises by anybody other than Tenant (all of the foregoing
actions are collectively referred to as a "Transfer") without obtaining, on each
occasion, the prior written consent of Landlord, which shall not be unreasonably
withheld or delayed.

     For purposes of this Lease, a Permitted Transfer shall mean an assignment
of this Lease by Tenant to its wholly owned subsidiary or immediate controlling
corporation or affiliated corporation (for such period of time as such
corporation remains such a subsidiary or such a controlling corporation or such
an affiliated corporation, respectively, it being agreed that the subsequent
sale or transfer of stock resulting in a change in voting control, or any other
transaction(s) having the overall effect that such corporation ceases to be such
a subsidiary or such a controlling corporation or such an affiliated
corporation, respectively, of Tenant, shall be treated as if such sale or
transfer or transaction(s) were, for all purposes, an assignment of this Lease
governed by the provisions of this Section 6.1.11 and not a Permitted Transfer),
provided (and it shall be a condition of the validity of any such assignment)
that such wholly owned subsidiary or such immediate controlling corporation or
such an affiliated corporation first agree directly with the Landlord to be
bound by all of the obligations of Tenant hereunder, including, without
limitation, the obligation to pay the rent and other amounts provided for under
this Lease, the covenant to use the Premises only for the purposes specifically
permitted under this Lease and the covenant against further assignment; but such
assignment shall not relieve Tenant herein named of any of its obligations
hereunder, and Tenant shall remain fully liable therefor.

     As used herein, "affiliate" shall mean any entity that is under common
direct or indirect control with Tenant. "Control" shall mean ownership of fifty-
one percent (51%) or more of the voting securities or rights of the controlled
entity (which includes the right to elect the directors of the corporation or
the equivalent if such entity is not a corporation).

     In addition, for the purposes of this Lease, the sale or transfer (which
term shall include, without limitation, the exchange, issuance and redemption)
of forty-nine percent (49%) or more, or such smaller percentage as would result
in a change in the voting control, of the voting stock of Tenant (if the Tenant
is a corporation), the voting stock of any corporate guarantor of Tenant

                                      16
<PAGE>

(whether or not specified in Section 1.1 hereof), or the voting stock of any
immediate or remote controlling corporation of Tenant (whether such sale or
transfer occurs at one time or at intervals so that, in the aggregate, over the
term of this Lease, such transfer shall have occurred), or any other
transaction(s) overall having the effect of a change in voting control or
substantially the same effect if the entity in question is not a corporation
(such as, without limitation, a change in the number or the identity of partners
of a partnership or of beneficiaries of a trust), shall be treated as if such
sale or transfer or transaction(s) were, for all purposes, an assignment of this
Lease and shall be governed by the provisions of this Section 6.1 .11 and shall
not be a Permitted Transfer; provided, however, that the provisions of this
sentence shall not apply to the transaction by which Tenant becomes, or to the
trading of Tenant's voting stock while the Tenant remains, a so-called reporting
public corporation under the provisions of the Securities Exchange Act of 1934,
as amended, the outstanding voting stock of which is registered in accordance
with the provisions of the Securities Act of 1933, as amended, and actively
traded on the New York Stock Exchange or another recognized, national securities
exchange (and for the purposes hereof, the term 'voting stock" shall refer to
shares of stock regularly entitled to vote for the election of directors of the
corporation).

     Notwithstanding the foregoing provisions of this Section 6.1.11, in the
event that all or substantially all of Tenant's operations are being transferred
to another entity by way of merger, consolidation or sale of substantially all
of the stock therein or assets thereof, the Landlord will not unreasonably
withhold consent to an assignment of this Lease to said resulting or acquiring
entity, provided (and it shall be a condition of the validity of any such
assignment), without limitation, that: (i) such entity shall first agree
directly with the Landlord to be bound by all of the obligations of Tenant
hereunder, including, without limitation, the obligation to pay the rent and
other charges provided for under this Lease, and the covenant against further
assignment; (ii) such assignment shall not relieve the Tenant herein named of
any of its obligations hereunder, and the Tenant shall remain fully liable
therefor; and (iii) the Tenant shall furnish Landlord with such information
regarding such entity as Landlord may reasonably require, including, without
limitation, information regarding good financial ability and business experience
, and Landlord determines in the Landlord's reasonable judgment that such entity
(a) at the time of such assignment, is of good creditworthiness and net worth at
lest equal to those of Tenant herein named on the date of the execution hereof
(or, if then greater, on the date such consent is requested), and (b) is
acquiring such operations as a going business. In addition, if the performance
of the obligations of the Tenant herein named are guaranteed, then such entity
or a substantially comparable guarantor shall be of net worth and
creditworthiness at least equal to those of the then existing guarantor of the
Tenant.

     In the event Tenant assigns this Lease or sublets the whole or any part of
the Premises (other than as expressly hereinabove permitted to its wholly owned
subsidiary or its immediate controlling corporation or with the Landlord's prior
written consent), in addition to and without limiting any of Landlord's rights
and remedies on account of the resulting default hereunder by Tenant, Landlord
shall have the right to terminate this Lease by giving Tenant notice of
Landlord's desire so to do, in which event this Lease shall terminate on the
date specified by Landlord in such notice all as if such date were the date
specified in Section 1.1 hereof as the Expiration Date.

                                      17
<PAGE>

     If Tenant does enter into a Transfer permitted hereunder (other than a
Permitted Transfer), and if the consideration, rent, or other charges payable to
Tenant under such transfer exceed the sum of (i) the Annual Base Rent and
Additional Rent to be paid hereunder (pro rated based on floor area in the case
of a subletting, license or other occupancy of less than the entire area of the
Premises) and (ii) Tenant's Transfer Expenses, then Tenant shall pay to
Landlord, as additional rent, the entire amount of such excess in the case of an
assignment and fifty per cent (50%) of such excess in the case of a subletting,
when and as received. Tenant shall not, however, be required to include in any
such calculation any proceeds from a sale or rental to the Transferee of any of
Tenant furniture, fixtures or equipment located in or on the Premises provided
that any value allocated to such furniture, fixtures and equipment is a good
faith approximation of the actual value thereof. Tenant's Transfer Expenses
shall mean Tenant's reasonable and necessary payments to third parties in
connection with such a Transfer including, without limitation, those incurred on
account of brokerage, legal and fit-up costs together with such share, if any,
of the unamortized cost of any Tenant Work as is reflected in the consideration,
rent and other charges payable to Tenant (it being understood that Tenant shall
be entitled to first recover all of Tenant's Transfer Expenses before Landlord
shall be entitled to receive any portion).

     It shall not be unreasonable for Landlord to withhold its consent to any
proposed assignment of this Lease or to any proposed subletting of all or any
part of the Premises if Landlord determines in the exercise of its prudent
business judgment that the following conditions have not been satisfied: (i) the
proposed assignee or sublessee has a good business reputation; (ii) the use to
be made of the Premises by the proposed assignee or sublessee shall not be of a
type of use which is reasonably likely to cause more extensive wear and tear to
the Premises than that to be carried on by the Tenant herein named (to the
extent that the same is not reparable as required herein) or to pose a threat of
environmental contamination or harm to any third party or injury to the Building
and will not create any additional expenses or costs to the Landlord, and is
otherwise reasonably consistent with all of the terms, covenants and conditions
of this Lease; and (iii) neither the proposed use nor the proposed assignee or
sublessee will adversely affect the residual value of the Building after the
expiration of the Term. It shall be a condition of the validity of any such
assignment or subletting that the assignee or sublessee agrees directly with
Landlord, in form reasonably satisfactory to Landlord, to be bound by all the
obligations of Tenant hereunder (to the extent appropriate in the case of a
sublease), including, without limitation, the covenant against further
assignment or subletting, but such assignment or subletting shall not relieve
the Tenant named herein of any of the obligations of Tenant hereunder, and
Tenant shall remain fully liable therefor. Tenant shall, upon demand, reimburse
Landlord for the actual and reasonable third party legal fees and expenses
incurred by Landlord in processing any request to assign this Lease or to sublet
all or any portion of the Premises.

     In all events notwithstanding any Transfer, and whether or not the same is
a Permitted Transfer or consented to, Tenant's and any guarantor's liability to
Landlord shall remain direct and primary. In the case of any requested consent
to a Transfer, Tenant shall deliver to Landlord at the time of such Transfer (i)
a true and complete copy of the proposed instrument containing all of the terms
and conditions of such Transfer, and (ii) a written agreement of the Transferee,
in form reasonably approved by Landlord, agreeing with Landlord to perform and
observe all of the terms, covenants and conditions of this Lease (to the extent
appropriate to a sublease). Any

                                      18
<PAGE>

assignee shall upon request execute and deliver such instruments as Landlord
reasonably requests in confirmation thereof (and Tenant agrees that such
assignee's failure to do so shall be grounds for withholding of Landlord's
consent). So long as an Event of Default exists hereunder, Landlord may collect
rent and other charges from such Transferee (and upon notice such Transferee
shall pay directly to Landlord) and apply the net amount collected to the rent
and other charges herein reserved, but no such collection shall be deemed a
waiver of the provisions of this Section, or the acceptance of the Transferee as
a tenant, or a release of Tenant or any guarantor from direct and primary
liability for the performance of all of the covenants of this Lease. The consent
by Landlord to any Transfer shall not relieve Tenant from the obligation of
obtaining the express consent of Landlord to any modification of such Transfer
or a further assignment, subletting, license or occupancy; nor shall Landlord's
consent alter in any manner whatsoever the terms of this Lease, to which any
Transfer at all times shall be subject and subordinate. Failure by Landlord to
consent to a proposed transfer shall never cause a termination of this Lease.

     6.2.  Landlord's Covenants; Quiet Enjoyment.  Tenant, subject to the terms
           -------------------------------------
and provisions of this Lease, upon payment of the rent and observing, keeping
and performing all of the terms and provisions of this Lease on Tenant's part to
be observed, kept and performed, shall lawfully, peaceably and quietly have,
hold, occupy and enjoy the Premises during the Term hereof, without hindrance or
ejection by any persons claiming under Landlord to have title to the premises
superior to Tenant, and it is understood and agreed that this covenant and any
and all other covenants of Landlord contained in this Lease shall be binding
upon Landlord and Landlord's successors only with respect to breaches occurring
during Landlord's and Landlord's successors' respective ownership of Landlord's
interest hereunder.

     6.3.  Interruptions.  Landlord or its agents or contractors, Landlord shall
           -------------
not be liable to Tenant in damages or by reduction of rent or otherwise by
reason of inconvenience or annoyance or for loss of business arising from
Landlord or its agents, employees or independent contractors entering the
Premises and/or the Lot for any of the purposes authorized in this Lease. In
case Landlord is prevented or delayed from performing any covenant or duty to be
performed on Landlord's part by reason of any cause reasonably beyond Landlord's
control, Landlord shall not be liable to Tenant therefor, nor shall the same
give rise to a claim in Tenant's favor that such failure constitutes
constructive eviction from the Premises. Except in emergencies, Landlord will,
at Tenant's request, stop such services or utilities only after business hours.

     6.4.  Real Estate Taxes and Insurance.  To the extent not required to be
           -------------------------------
paid by Tenant hereunder, Landlord shall pay, on or before the date due, all
real estate taxes on the Premises and Lot, and Landlord shall pay, on or before
the date due, all insurance premiums on insurance required to be carried by
Landlord as provided below so long as Tenant has made timely payment of all
                     -----
additional rent under Sections 4.3.1 and 4.4.1.


     6.5.  Landlord's Hazardous Materials Responsibilities.  Landlord shall not
           -----------------------------------------------
itself, nor shall it permit or suffer persons acting under Landlord, either with
or without negligence, to release during the Term hereof any hazardous materials
prohibited by law on the Lot. Except as

                                      19
<PAGE>

the same are made Tenant's responsibility by the provisions of Section 6.1.8,
Landlord shall promptly take all actions at its sole expense as are necessary to
remediate any release of hazardous materials in accordance with and to the
extent required by law. Landlord shall indemnify, save harmless and defend
Tenant from all liability, claim, damage, cost or loss (including reasonable
fees of legal counsel of the Landlord's (or an insurer assuming liability)
choice against whom Tenant makes no reasonable objection) which may at any time
(whether or not prior to or after expiration of the Term of this Lease) be
imposed upon, incurred by or asserted or awarded against Tenant arising from or
out of the violation of the foregoing provision.


     6.6.  Landlord's Casualty Insurance.  Landlord shall maintain the following
           -----------------------------
insurance on the Premises: (a) property damage insurance with such deductibles
and in such amounts as may from time to time be carried by reasonably prudent
owners of similar buildings in the area in which the Property is located,
provided that in no event shall Landlord carry less than "special form" property
damage insurance, with so-called "broad-form" coverage (including change in law
endorsements), in an amount equal to one hundred percent (100%) of the full
replacement cost of the Building (excepting footings and foundations) and other
improvements comprising the Premises, with an agreed amount clause, and
including a waiver of subrogation; and (b) rent continuation insurance for a
period of at least two years in an amount not less than the gross annual rental
income hereunder (meaning Annual Base Rent and all additional rent payable).
Tenant shall be named as an additional insured under such policy, as its
interest may appear. Landlord may satisfy such insurance requirements by
including the Property in a so-called "blanket" insurance policy, provided that
the amount of coverage allocated to the Property shall fulfill the foregoing
requirements.


                                 ARTICLE VII.
                                 ------------

                          Insurance; Casualty, Taking
                          ---------------------------

     7.1.  Insurance by Landlord.  If Tenant fails to perform any covenant in
           ---------------------
Section 7.1.1, then without limiting any of Landlord's other rights and
notwithstanding any other provision of this Lease concerning notice and cure of
defaults, Landlord may obtain such insurance, and Tenant shall pay the actual
cost thereof upon demand as additional rent.

           7.1.1.  Public Liability Insurance.  Tenant shall maintain throughout
                   --------------------------
the Term (and such further time as Tenant or any person claiming
through it occupies any part of the Premises) commercial general liability
insurance against all claims for injury to persons or property in connection
with the Premises naming Landlord (and if requested, Landlord's mortgagees and
Landlord's members, managers, partners, property manager and any other party in
privity of estate with Landlord) as additional insureds, in an amount which
shall be equal to the amount set forth in Section 1.1. Such insurance shall
provide that it will not be subject to cancellation, termination or change
except after at least 30 days' prior written notice to Landlord (and Landlord's
mortgages and other additional insureds). Each such policy shall be written by a

                                      20
<PAGE>

reputable and financially sound, duly licensed and admitted insurance company
with an AM Best rating of A-VII or better. A duly executed certificate and copy
of such policy shall be deposited with Landlord at the beginning of the Term,
and a renewal certificate shall be so deposited not less than 30 days prior to
their normal expiration. Such insurance may be maintained in part through so-
called "umbrella" coverage reasonably satisfactory to Landlord.

     7.2.  Waivers of Subrogation.  Any insurance carried by either Landlord or
           ----------------------
Tenant with respect to the Premises or personal property on the Premises shall
include an endorsement containing a waiver by the insurer of its rights of
subrogation against the other party, to the extent available (and if available
only at an additional cost, then if the other party agrees to pay such
additional cost). Without limiting any other provisions of this Lease, each
party hereby waives any rights of recovery against the other for injury or loss
due to hazards covered by such insurance, to the extent of the recovery under
such insurance (or to the extent of the recovery that could have occurred if
coverage had been maintained as expressly required by this Lease).

     7.3.  Damage or Destruction of Premises.  If the Premises or any part
           ---------------------------------
thereof shall be damaged by fire or other insured casualty, then, subject to the
following provisions of this Section, Landlord shall proceed with diligence,
subject to then applicable laws and at the expense of Landlord (but only to the
extent of insurance proceeds received and made available to Landlord by any
mortgagee, Landlord agreeing to make available funds in the amount of Landlord's
deductible and to use diligent efforts to obtain the mortgagee's consent to
release of such proceeds) to cause to be repaired such damage, excluding any
items installed or paid for by Tenant which Tenant is required or permitted to
remove upon expiration (which items shall be Tenant's responsibility to repair).
However, if any damage occurs through the act or neglect of Tenant or persons
acting under Tenant or if any act or neglect of Tenant or such person prevents
Landlord or its mortgagees from collecting all insurance proceeds, then the cost
of repairing the casualty damage shall be paid by Tenant and there shall be no
abatement of rent except to the extent any insurance proceeds are actually
received by Landlord or mortgagees or proceeds would have been recovered if
Landlord had maintained the insurance required to be maintained under Section
6.4 (Landlord agreeing to, if necessary). If any casualty occurs to more than
fifty percent of the Premises during the last eighteen (18) months of the Term
(as the same may have been extended), then in any such case, this Lease and the
Term hereof may be terminated at the election of Landlord or Tenant by a notice
in writing of its election so to terminate given to the other party within two
(2) months following such casualty, the effective termination date being not
less than thirty (30) nor more than sixty (60) days after the date of such
notice.


     Tenant shall be entitled to a just abatement of Annual Base Rent and all
Additional Rent during the period of impaired use of the Premises. If neither
Landlord nor such mortgagee (i) has commenced such replacement within the
earlier of six (6) months following such casualty, or (ii) having so commenced
such replacement, has substantially completed such restoration within twelve
(12) months following such casualty, then Tenant may, until any such aforesaid
replacement commences in the case of (i) or is so completed in the case of (ii),
terminate this Lease by giving at least thirty (30) days prior written notice
thereof to Landlord (which termination shall be vitiated and rendered null and
void if Landlord or such mortgagee so commences in the case of (i) or completes
in the case of (ii) within said thirty (30) day period).

                                      21
<PAGE>

Except as provided in this paragraph, Tenant's obligation to pay all rent and to
perform and observe all other covenants and conditions of this Lease shall not
be affected by any damage or casualty, and the Term of this Lease and rent
hereunder shall continue nonetheless.

     7.4.  Eminent Domain.  In the event that all or any substantial part of the
           --------------
Premises (meaning more than 25% of floor area) is taken, or if substantially all
of Tenant's access to the Premises is taken and not replaced by Landlord with
reasonable promptness, or if Tenant's parking is taken and not replaced by
Landlord with reasonable promptness (not to exceed 15 days) such that Tenant has
less than two parking spaces for each 1,000 square feet of rentable square feet
of the Premises remaining following such taking (other than for temporary use,
hereafter described) by public authority under power of eminent domain (or by
conveyance in lieu thereof), then by notice given within three months following
the recording of such taking (or conveyance) in the appropriate registry of
deeds, this Lease may be terminated at Landlord's or Tenant's election 30 days
after such notice, and Annual Base Rent, Additional Rent and other charges shall
be apportioned as of the date of termination. If this Lease is not terminated as
aforesaid, Landlord shall within the time periods described in Section 7.3
above, diligently restore what may remain of the Premises (excluding any items
installed or paid for by Tenant which Tenant is permitted or may be required to
remove upon expiration) to a tenantable condition. In the event some portion of
rentable floor area is taken (other than for temporary use) and this Lease is
not terminated, Annual Base Rent, Additional Rent and other charges shall be
proportionally abated for the remainder of the Term. In the event of any taking
of the Premises or any part thereof for temporary use (meaning a period of one
year or less), (i) this Lease shall be and remain unaffected thereby and rent
shall not abate, and (ii) Tenant shall be entitled to receive for itself such
portion or portions of any award made for such use with respect to the period of
the taking which is within the Term, provided that if such taking shall remain
in force at the expiration or earlier termination of this Lease, then Tenant
shall pay to Landlord a sum equal to the reasonable cost of performing Tenant's
obligations hereunder with respect to surrender of the Premises and upon such
payment shall be excused from such obligations.


     So long as Tenant is not then in breach of any covenant or condition of
this Lease following notice thereof and expiration of any applicable cure
period, any specific damages which are expressly awarded to Tenant on account of
its furniture, fixtures or relocation expenses, and specifically so designated,
shall belong to Tenant. Except as provided in the preceding sentences of this
paragraph, Landlord reserves to itself, and Tenant releases and assigns to
Landlord, all rights to damages accruing on account of any taking or by reason
of any act of any public authority for which damages are payable. Tenant agrees
to execute such further instruments of assignment as may be reasonably requested
by Landlord, and to turn over to Landlord any damages that may be recovered in
any proceeding or otherwise (except those expressly awarded to Tenant as
provided above).

                                 ARTICLE VIII.
                                 -------------

                                    Default
                                    -------

     8.1.  Events of Default.  An Event of Default shall exist hereunder if (i)
           -----------------
Tenant fails to pay Annual Base Rent, additional rent or any other sum when due
and such default continues for

                                      22
<PAGE>

ten (10) days after notice is given; or (ii) if more than two payment default
notices are properly given under clause (i) in any twelve month period, or (iii)
if Tenant makes any Transfer of the Premises in violation of this Lease, or (iv)
if a petition is filed by Tenant for insolvency or for appointment of a
receiver, trustee or assignee or for adjudication, reorganization or arrangement
under any bankruptcy act or if any similar petition is filed against Tenant and
such petition is not dismissed within ninety days thereafter, or (v) if any
representation or warranty expressly made in writing by Tenant is untrue in any
material respect and the same is not cured within thirty (30) days after notice
to Tenant specifying in reasonable detail the representation or warranty
breached and the facts giving rise to the breach thereof, or (vi) if Tenant
falls to perform any other covenant or condition hereunder and such default
continues longer than any period expressly provided for the correction thereof
(and if no period is expressly provided then for thirty (30) days after notice
is given, provided, however, that such thirty (30) day period shall be
reasonably extended in the case of non-monetary default if the matter complained
of can be cured but the cure cannot be completed within such period and Tenant
begins promptly and thereafter diligently completes the cure; but if such
matters cannot be cured then there will be no cure period). Upon the occurrence
of any Event of Default, Landlord and its agents lawfully may, in addition to
any remedies for any preceding breach, immediately or at any time thereafter
without demand or notice and with or without process of law, enter upon any part
of the Premises in the name of the whole or mail or deliver a notice of
termination of the Term of this Lease addressed to Tenant at the Premises or any
other address herein, and thereby terminate the Term and repossess the Premises
as of Landlord's former estate. At Landlord's election such notice of
termination may be included in any notice of default. Upon such entry or mailing
the Term shall terminate, all executory rights of Tenant and all obligations of
Landlord will immediately cease, and Landlord may, by proper judicial
proceedings, expel Tenant and all persons claiming under Tenant and remove their
effects without any trespass and without prejudice to any remedies for arrears
of rent or prior breach. If any payment of Annual Base Rent, additional rent, or
other sum is not paid within five (5) days following the due date thereof, then
(in addition to Landlord's foregoing remedies) Landlord may at its option in
addition to all other remedies hereunder impose an administrative late charge on
Tenant equal to 3% of the amount in question for every failure so to pay when
due, which late charge will be due upon demand as additional rent.


     If the Term is terminated for default, the Tenant covenants, as an
additional cumulative obligation after such termination, to pay on demand all of
Landlord's actual and reasonable third party costs, including attorneys fees,
related thereto and in collecting amounts due and all reasonable expenses in
connection with reletting, including tenant inducements, brokerage commissions,
fees for legal services, expenses of preparing the Premises for relettings and
the like ("Reletting Expenses"). It is agreed that Landlord may (i) relet the
Premises or part or parts thereof for a term or terms which may be equal to,
less than or exceed the period which would otherwise have constituted the
balance of the Term, and may grant such tenant inducements, including free rent,
as Landlord in its sole discretion considers advisable in connection with any
such relettings, and (ii) make such alterations to the Premises as Landlord in
its sole discretion considers advisable, and no failure to relet or to collect
rent under any reletting shall operate to reduce Tenant's liability.

                                      23
<PAGE>

     If the Term of this Lease is terminated for default, then unless and until
Landlord elects lump sum liquidated damages described in the next paragraph
below, Tenant covenants, as an additional cumulative obligation after any such
termination, to pay punctually to Landlord all the sums and perform all of its
obligations in the same manner as if the Term had not been terminated. In
calculating such amounts Tenant will be credited with the net proceeds of any
rent then actually received by Landlord from a reletting of the Premises after
deducting all sums to be paid by Tenant and not then paid.

     If this Lease is terminated for default, then Tenant covenants, as an
additional cumulative obligation after termination, to pay forthwith to
Landlord, at Landlord's election made by written notice at any time after
termination, as liquidated damages a single lump sum payment equal to the sum of
(i) all sums to be paid by Tenant hereunder which are due and unpaid at the time
of such election, plus (ii) the excess of all of the Annual Fixed Rent and
Additional Rent reserved for the residue of the Term (with additional rent on
account of taxes and insurance deemed to increase 3% in each year on a
compounding basis), over the then net fair rental value of the Premises for the
same period, discounted to the then net present value at an interest rate equal
to (x) the Base Rate as announced by BankBoston, N.A. (or its successor by
merger), as then in effect, minus (y) one percent (1%).

     Without implying that other covenants do not survive, the covenants of this
Section shall survive the Term.

     8.2.  Remedies Cumulative; Jury Waiver.  The specific remedies to which
           --------------------------------
either party may resort under this Lease, and all other rights and remedies are
cumulative, and any two or more may be exercised at the same time. Nothing in
this Lease shall limit the right of either party to prove and obtain in
proceedings for bankruptcy or insolvency an amount equal to the maximum allowed
by any statute or rule of law in effect at the time. Landlord and Tenant waive
trial by jury in any action to which they are parties.

     8.3.  Waivers of Default; Accord and Satisfaction.  No consent by Landlord
           -------------------------------------------
or Tenant to any act or omission which otherwise would be a breach of covenant
shall be construed to permit other similar acts or omissions. Neither party's
failure to seek redress for violation or to insist upon the strict performance
of any covenant, neither the payment by Tenant nor the receipt by Landlord of
rent with knowledge of any breach of covenant, shall be deemed a consent to or
waiver of such breach. No breach of covenant shall be implied to have been
waived unless such waiver is in writing, signed by the party benefiting from
such covenant and delivered to the other party. No acceptance by Landlord of a
lesser sum than the Annual Base Rent, additional rent or any other sum due shall
be deemed to be other than on account of the earliest installment of such rent
or other sum due, nor shall any endorsement or statement on any check or in any
letter accompanying any check or payment be deemed an accord and satisfaction;
and Landlord may accept such check or payment without prejudice to Landlord's
right to recover the balance of such installment or pursue any other right or
remedy. The delivery of keys (or similar act) to Landlord shall not operate as a
termination of the Term or an acceptance or surrender of the Premises. The
acceptance by Landlord of any rent following the giving of any default and/or
termination notice shall not be deemed a waiver of such notice (except as to any
payment

                                      24
<PAGE>

expressly accepted by Landlord in waiver thereof which waiver is confirmed by
Landlord in writing).


     8.4.  Curing and Enforcement.  If either party fails to perform any
           ----------------------
covenant within any applicable cure period following written notice thereof,
then the other at its option may (without waiving any right or remedy for the
other's non-performance) at any time thereafter perform the covenant for the
account of the other party (without regard, in the case of any failure to
perform by Landlord, to the extended cure right afforded to Landlord's mortgagee
under Section 10.1 hereof). Each party shall reimburse the other's actual and
reasonable third party costs (including reasonable attorneys' fees) of so
performing on demand. Notwithstanding any other provision concerning cure
periods, each party may cure any nonperformance for the account of the other
after such notice to the other, if any, as is reasonable under the circumstances
if curing prior to the expiration of the applicable cure period is reasonably
necessary to prevent likely damage to the Premises or possible injury to
persons, or to protect the curing party's interest in the Premises.


                                  ARTICLE IX.
                                  -----------

                           Miscellaneous Provisions
                           ------------------------

     9.1.  Notice.  All notices, consents, approvals and the like shall be in
           ------
writing and shall be delivered in hand, by any courier service providing
receipts, or mailed by certified mail addressed, if to Tenant, at the Original
Address of Tenant or such other addresses (up to three in total) within the
United States as Tenant shall have last designated by notice to Landlord, with a
copy sent in like manner to Stephen T. Langer, Esq., Mintz Levin, One Financial
Center, Boston, MA 02111 and, if to Landlord, at the Original Address of
Landlord or such other address within the United States as Landlord shall have
last designated by notice to Tenant, with a copy sent in like manner to Goulston
& Storrs, P.C., 400 Atlantic Avenue, Boston, Massachusetts 02110, Attention:
Phillip G. Levy, Esq. If requested, Tenant shall deliver copies of all notices
in like manner to Landlord's mortgagees and other persons having a relationship
to the Premises at such address within the United States as designated from time
to time by Landlord or such mortgagee. Any notice so addressed shall be deemed
duly given upon delivery, attempted delivery or refusal of delivery, whichever
occurs first, to any person reasonably appearing to be an agent or employee
working in the offices of the addressee.


     9.2.  Limitation of Landlord's Liability.  Tenant agrees that Landlord
           ----------------------------------
shall be liable only for breaches of its covenants occurring while it is owner
of the Premises (provided, however, that if Landlord from time to time is lessee
of the ground or improvements constituting the Premises, then Landlord's period
of ownership of the Premises shall be deemed to mean only that period while
Landlord holds such leasehold interest). Tenant (and each person acting under
Tenant) agrees to look solely to Landlord's interest from time to time in the
Premises and Lot, together with the rents, issues, profits and proceeds of the
same, for satisfaction of any claim against Landlord. No trustee, beneficiary,
partner, manager, member, agent or employee of Landlord (or of any mortgagee or
any ground or improvements lessor) shall ever be personally or

                                      25
<PAGE>

individually liable; nor shall it or they ever be answerable or liable in any
equitable judicial proceeding or order beyond the extent of their interest in
the Premises, and such rents, issues, profits and proceeds. Any lien obtained to
enforce any judgment against Landlord shall be subject and subordinate to any
mortgage encumbering the Premises except as otherwise set forth herein. In no
event shall Landlord or Tenant ever be liable to the other for indirect or
consequential damages. As used in this Lease, the term Landlord shall mean the
party from time to time holding Landlord's interest hereunder.


     9.3.  Excusable Delay.  If either party is delayed in performing it
           ---------------
obligations (other than an obligation to pay money) hereunder by causes beyond
such party's reasonable control, including war, civil commotion, acts or
regulations of government, moratoria and casualty, theft, labor difficulties, or
the unavailability of labor, materials, equipment or utilities from customary
sources upon customary terms, or by acts, neglects or delays of the other party
(or persons acting under such other party), then such delay shall not be counted
in determining the time during which such performance is to be completed.
Financial inability will never be a cause beyond either party's control.


     9.4.  Applicable Law and Construction.  This Lease may be executed in
           -------------------------------
counterparts. The covenants of Landlord and Tenant are independent, and such
covenants shall be construed as such in accordance with the laws of the state
where the Premises are located. If any provisions shall to any extent be
invalid, the remainder shall not be affected. Other than contemporaneous
instruments executed and delivered of even date, if any, this Lease may be
amended only by instrument in writing executed and delivered by both Landlord
and Tenant. The provisions of this Lease shall bind Landlord and Tenant and
their respective successors and assigns, and shall inure to the benefit of
Landlord and its successors and assigns and of Tenant and its permitted and
assigns. Where the phrases persons acting under Landlord or Tenant" or "persons
claiming through Landlord or Tenant" or similar phrases are used, the persons
included shall be invitees of Landlord or Tenant or any transferee or
independent contractor of Landlord or Tenant and all of their respective
employees, servants, contractors, agents and invitees. The titles are for
convenience only and shall not be considered a part of the Lease. If Tenant is
granted any extension or other option, to be effective the exercise (and notice
thereof) shall be unconditional; and if Tenant purports to condition the
exercise of any option or to vary its terms in any manner, then the purported
exercise shall be ineffective. The enumeration of specific examples of a general
provision shall not be construed as a limitation of the general provision.
Unless a party's approval or consent is to be required by the express terms of
this Lease not to be unreasonably withheld, such approval or consent may be
withheld at the party's sole discretion. Where Landlord is required reasonably
to consent to or approve any matters, the same shall always be subject to
obtaining the prior approval of any mortgagee having approval rights as to such
matters under any mortgage (which Landlord agrees to use reasonable efforts to
obtain in those instances where Landlord intends so to grant its consent or
approval). The submission of a form of this Lease or any of its terms shall not
constitute an offer by Landlord to Tenant; but a leasehold shall only be created
and the parties bound when this Lease is executed and delivered by both Landlord
and Tenant. Nothing herein shall be construed as creating the relationship
between Landlord and Tenant of principal and agent, or of partners or joint
ventures or any relationship other than landlord and tenant. All covenants of
this Lease, except covenants to pay

                                      26
<PAGE>

Annual Base Rent and respecting the care of the Premises, shall survive the
Term. This Lease and all consents, notices, approvals and all other related
documents may be reproduced by any party by facsimile, photographic, microfilm,
microfiche or other reproduction process and the originals may be destroyed; and
each party agrees that any reproductions shall be as admissible in evidence in
any judicial or administrative proceeding as the original itself (whether or not
the original is in existence and whether or not reproduction was made in the
regular course of business), and that any further reproduction of such
reproduction shall likewise be admissible. If any payment in the nature of
interest provided for in this Lease shall exceed the maximum interest permitted
under controlling law, as established by final judgment of a court, then such
interest shall instead be at the maximum permitted interest rate as established
by such judgment. Landlord's title is and always shall be paramount to the title
of Tenant, and nothing in this Lease shall empower Tenant to do any act which
can, shall or may encumber the title of Landlord.


     9.5.  Estoppel Certificate.  Within fifteen (15) days of either party's
           --------------------
request, the other agrees to execute, acknowledge and deliver a statement in
writing certifying whether this Lease is in full effect (or if there has been
any amendment whether the same is in full effect as amended and stating the
amendment or amendments), the Commencement Date, the amount of and the dates to
which the Annual Base Rent (and additional rent and all other charges) have been
paid and, as of its best knowledge and belief, any other information concerning
performance, construction, tenancy, possession or other matters of reasonable
interest to prospective lenders or purchasers. Both parties agree that any such
statement may be relied upon by any person to whom the same is delivered.


     9.6.  Notice of Lease.  Neither party shall record this Lease, but each
           ---------------
party will, upon request of the other, execute a recordable notice of lease in
form reasonably approved by the parties and which notice shall contain the
provisions of this Section, and upon expiration or termination of the Term for
whatever reason a like notice of termination of lease.


     9.7.  Landlord's Default.  Landlord shall use due diligence in performing
           ------------------
its covenants under this Lease. In no event shall Landlord be in default unless
notice thereof has been given to Landlord (and all mortgagee of which Tenant has
notice) and Landlord (or any such mortgagees at its sole discretion) fails to
perform within 30 days (provided, however, that such period shall be reasonably
extended if such performance begins promptly within such period and thereafter
is diligently pursued or if such mortgagee notifies Tenant within such period
that it intends to cure on behalf of Landlord and thereafter begins and
diligently pursues curing with reasonable promptness).


     9.8.  Brokers.  Each party warrants and represents to the other that it
           -------
has not dealt with any broker in connection with this Lease or the Premises
except for the Brokers, if any, listed in Section 1.1; and each agrees to
indemnify and save the other harmless in the manner elsewhere provided in this
Lease from any breach of this warranty and representation, which will survive
the termination of the Term. Landlord agrees to pay any commission due to
Landlord's Broker.

                                      27
<PAGE>

     9.9.   Intentionally Deleted.
            ----------------------


     9.10.  Tenant as Business Entity.  Tenant and Landlord each warrant and
            -------------------------
represent to the other that (a) each is duly organized, validly existing and in
good standing under the laws of the jurisdiction in which such entity was
organized; (b)each has the authority to own its property and to carry on its
business as contemplated under this Lease; (c) each is in compliance with all
laws and orders of public, authorities applicable to it; (d) each has duly
executed and delivered this Lease; (e) the execution, delivery and performance
by each of this Lease (i) are within the powers of each, (ii) have been duly
authorized by all requisite action, (iii) will not violate any provision of law
or any order of any court or agency of government, or any agreement or other
instrument to which each is a party or by which it or any of its property is
bound, or (iv) will not result in the imposition of any lien or charge on any of
it's property, except by the provisions of this Lease; and (f) the Lease is a
valid and binding obligation of each in accordance with its terms. This warranty
and representation shall survive the expiration or earlier termination of the
Term.


     9.11.  Security Deposit.  On the execution of this Lease, Tenant shall pay
            ----------------
to Landlord as a security deposit for the performance of the obligations of
Tenant hereunder any amount specified therefor in Section 1.1. Said security
deposit may be mingled with other funds of Landlord and no fiduciary
relationship shall be created with respect to such deposit, nor shall Landlord
be liable to pay Tenant interest thereon. If Tenant shall fail to perform any of
its obligations under this Lease after notice thereof and the expiration of any
applicable cure period, Landlord may, but shall not be obliged to, apply the
security deposit to the extent necessary to cure the default, and Tenant shall
be obliged to reinstate such security deposit to the original amount thereof
upon demand. Within 30 days after the expiration or sooner termination of the
Term the security deposit, to the extent not so applied, shall be returned to
the Tenant without interest.


     9.12.  Financial Reports.  So long as Tenant and/or any guarantor
            -----------------
respectively do not publicly report substantially the following financial
information to governmental authorities such as the Securities and Exchange
Commission, Tenant shall provide to Landlord with respect to both Tenant and
guarantor: (i) if either Tenant or guarantor compile the same for any other
purpose, quarterly reports (with respect to such quarter and the year to date)
delivered within forty-five (45) days after the end of each of the four
quarters) and (ii) in any case, an annual report (within ninety (90) days or
such additional reasonable time as may be necessary to diligently complete the
same after the end of each fiscal year) concerning their respective operations
prepared in accordance with either generally accepted accounting principles or
internationally accepted accounting standards as applicable to Tenant and
guarantor respectively, including balance select, income statement, statement of
changes in cash flow (annual report only). The quarterly, if any, and annual
reports shall be certified by the chief financial officer of Tenant and
guarantor respectively and the annual report shall be audited, at Tenant's
expense, by an independent certified public accountant. Tenant warrants and
represents that to the best of its knowledge the information contained in all
such reports will be materially true and complete.

                                      28
<PAGE>

Tenant also shall promptly (and in any event within 15 days after Tenant's own
receipt of notice) notify Landlord of any pending or threatened (if such threat
is contained in a written notice to Tenant or guarantor) suits, or proceedings
at law or in equity, or before or by any governmental authority or arbitration
panel, which (i) if adversely determined would materially affect the financial
integrity or he viability of Tenant or guarantor or (ii) involve the validity or
enforceability of this Lease.


     9.13.  Inducement Payment.  As soon as the following conditions have been
            ------------------
met: (i) there exists no default by Tenant of any of its obligations hereunder,
(ii) the Rent Commencement Date shall have occurred as provided herein and
Tenant shall have timely made its first payment of Base Rent hereunder and shall
have commenced occupying the Premises; and (iii) Tenant shall have delivered an
Estoppel Certificate to Landlord and any mortgagee as contemplated under Section
9.5, and (iv) Tenant shall have furnished an affidavit in form and substance
satisfactory to Landlord stating that all of the Tenant's Work theretofore
completed has been paid for in full (subject to retainage of up to ten percent
(10%) ("Retainage") and that any and all liens therefor that have been or may be
filed have been satisfied of record or waived, then the Landlord shall pay to
Tenant the sum of FIVE HUNDRED NINETY THOUSAND DOLLARS ($590,000.00) as an
inducement to Tenant to enter into this Lease ("Landlord's Payment").


     9.14.  Special Provision Regarding Letter of Credit.  Landlord is entering
            --------------------------------------------
into this Lease with Tenant based upon Tenant's commitment to fulfill all of
Tenant's obligations hereunder (collectively, the "Obligations"). To secure
Tenant's Obligations under this Lease, upon the execution of this Lease Tenant
shall furnish Landlord with an unconditional irrevocable Letter of Credit in the
face amount of $1,032,500 (the "Face Amount"), naming Landlord as the
beneficiary thereof, in form and substance and issued by a nationally-chartered
bank reasonably satisfactory to Lender (the "Letter of Credit"). The Letter of
Credit shall contain a so-called "evergreen " clause and shall remain
outstanding until the Rent Commencement Date shall have occurred, and (y) Tenant
shall have made its first payment of Base Rent hereunder, and (z) there shall be
no default by Tenant hereunder (the date upon which all such conditions have
been satisfied shall be referred to herein as the "Release Date"), and shall
specifically permit partial drawings. Upon the occurrence of an Event of Default
by Tenant hereunder, then, without prejudice to any other rights and remedies
available to Landlord at law or in equity or hereunder on account of such
default, Landlord shall have the right (but not the obligation) to draw upon the
Letter of Credit in any amount up to the full Face Amount thereof. No amounts
drawn by Landlord under the Letter of Credit shall be deemed to be a cure of
Tenant's default. Landlord shall reimburse Tenant for the amount of any letter
of credit fee charged by the issuing bank (up to a maximum of 2% of the Face
Amount).


  Upon the Release Date, provided all of Tenant's Obligations have been
satisfied, the Letter of Credit shall be returned to Tenant under this Section
9.14.

                                      29
<PAGE>

                                  ARTICLE X.
                                  ----------
                             Landlord's Financing
                             --------------------

     10.1.  Subordination and Superiority of Lease.  Tenant agrees that this
            --------------------------------------
Lease and the rights of Tenant hereunder will be subject and subordinate to any
lien of the holder of any existing or future mortgage, and to the rights of any
lessor under any ground or improvements lease of the Premises (all mortgages and
ground or improvements leases of any priority are collectively referred to in
this Lease as "mortgage," and the holder or lessor thereof from time to time as
a "mortgagee"), and to all advances and interest thereunder and all
modifications, renewals, extensions and consolidations thereof; provided,
                                                                ---------
however that the mortgagee executes and delivers to Tenant a written and
-------
recordable agreement, in form reasonably satisfactory to Tenant, in which the
mortgagee agrees that such mortgagee shall not disturb Tenant in its possession
of the Premises or in the enjoyment of its other rights hereunder, upon Tenant's
attornment to such mortgagee as Landlord and performance of its Lease covenants
(both of which conditions Tenant agrees with all mortgagees to perform). Tenant
agrees that any present or future mortgagee may at its option unilaterally elect
to subordinate, in whole or in part and by instrument in form and substance
satisfactory to such mortgagee alone, the lien of its mortgagee (or the priority
of its ground lease) to some or all provisions of this Lease.


     Tenant agrees that this Lease shall survive the merger of estates of ground
(or improvements) lessor and lessee. Except as may be provided in any
subordination agreement between mortgagee and Tenant, until a mortgagee (either
superior or subordinate to this Lease) either takes possession of the Premises
or forecloses Landlord's equity of redemption (or terminates in the case of a
ground or improvements lease) no mortgagee shall be liable for failure to
perform any of Landlord's obligations hereunder, and such mortgagee shall
thereafter be liable only after it succeeds to and holds Landlord's interest and
then only as limited herein. No mortgagee shall be bound by any payment of rent
more than one month in advance unless it shall have consented thereto. Tenant
shall, if requested by Landlord or any mortgagee, give notice of any alleged
non-performance on the part of Landlord to any such mortgagee provided that an
address for such mortgagee has been designated pursuant to Section 8.1; and
Tenant agrees that such mortgagee shall have a separate, consecutive reasonable
cure period of no more than thirty (30) days (to be reasonably extended in the
same manner Landlord's cure period is to be extended) following Landlord's cure
period during which such mortgagee may, but need not, cure any non-performance
by Landlord.

     10.2.  Rent Assignment.  If from time to time Landlord assigns this Lease
            ---------------
or the rents payable hereunder to any person, whether such assignment is
conditional in nature or otherwise, such assignment shall not be deemed an
assumption by the assignee of any obligations of Landlord; but the assignee
shall be responsible only for nonperformance of Landlord's obligations which
occur after it succeeds to and only while it holds Landlord's interest in the
Premises.


     10.3.  Other Instruments.  The provisions of this Article shall be self-
            -----------------
operative; nevertheless, Tenant agrees to execute, acknowledge and deliver any
commercially reasonable subordination, attornment or priority agreements or
other instruments from time to time

                                      30
<PAGE>

requested by Landlord or any mortgagee, provided that Tenant's obligations
hereunder shall not be increased and Tenant's rights shall not be diminished
thereby. Without limitation, where Tenant in this Lease indemnifies or otherwise
covenants for the benefit of mortgagees, such agreements are for the benefit of
mortgagees as third party beneficiaries; and at the request of Landlord, Tenant
from time to time will confirm such matters directly with such mortgagee.


     10.4.  Mutual Cost of Enforcement; Interest.  If either party is required
            ------------------------------------
to litigate against the other, then the prevailing party in such litigation
shall be entitled to recover from the non-prevailing party all reasonable
attorneys' fees and other costs of such litigation. If any amount due hereunder
remains unpaid after its due date, such amount shall bear interest at a per
annum rate equal to 4 points above the Prime Rate, as announced from time to
time by BankBoston, N.A. at its Boston office.


                                  ARTICLE XI.
                                  -----------

     11.1.  Special Provisions Regarding Potential Expansion Space. Landlord
            ------------------------------------------------------
has advised Tenant that it may be possible under applicable laws and codes to
expand the size of the Building (the "Potential Expansion") by approximately
40,000 rentable square feet (the "Potential Expansion Space"). Tenant
acknowledges that Landlord has made no representations or warranties whatsoever
regarding the feasibility of constructing or the feasibility of obtaining any
federal, state and local permits and approvals and approvals of third parties
(including, without limitation, Landlord's mortgagee(s)) which may be necessary
to permit the construction and/or operation of the Potential Expansion ("Permits
and Approvals"). Landlord hereby grants Tenant the exclusive right to negotiate
with Landlord as to the rental of the Potential Expansion Space on the terms and
conditions set forth herein. During the term of this Lease, Landlord shall not
commence any expansion of the size of the Building (or construction of
additional buildings on the Lot) without first notifying Tenant of its intent to
do so ("Landlord's Expansion Notice"). Landlord's Expansion Notice shall be
prepared in good faith and include the material business terms and conditions
upon which Landlord would process necessary applications for obtaining Permits
and Approvals, and thereafter construct the Potential Expansion Space and lease
such space to Tenant. Tenant shall have ten (10) business days following its
receipt of Landlord's Expansion Notice to respond in writing to Landlord as to
whether or not Tenant is interested in leasing the Potential Expansion Space on
the terms and conditions set forth in Landlord's Notice. Tenant's failure to
respond within such ten (10) business day period shall be deemed to be Tenant's
election not to lease the Potential Expansion Space and shall constitute a
waiver of Tenant's rights under this Section 11.1. If Tenant notifies Landlord
within such ten (10) business day period that it is interested in leasing such
Potential Expansion Space, Landlord and Tenant shall execute an amendment to
this Lease providing for the construction and leasing of the Potential Expansion
Space on the terms and conditions contained in Landlord's Expansion Notice (or
on such other terms and conditions as may be mutually acceptable to both parties
at such time) and Landlord shall thereafter use good faith efforts to obtain the
Permits and Approvals. Landlord's inability to obtain the Permits and Approvals
shall not constitute a default under the Lease or give rise to any remedy on the
part of Tenant.

                                      31
<PAGE>

     Unless and until Tenant receives Landlord's Expansion Notice, Tenant shall
have the right to notify Landlord of Tenant's desire to have the Potential
Expansion Space constructed ("Tenant's Expansion Notice"). Landlord shall have
twenty (20) business days following its receipt of Tenant's Expansion Notice
either (i) to furnish Tenant with Landlord's Expansion Notice, pursuant to which
Landlord would propose to use good faith efforts to obtain the Permits and
Approvals for and to construct the Potential Expansion Space and lease it to
Tenant as described above, or (ii) to elect not to pursue the permitting and
construction of the Potential Expansion Space but to allow Tenant to do so in
accordance with the provisions hereinafter set forth. If Landlord sends
Landlord's Expansion Notice but Landlord and Tenant are unable to agree upon the
terms and conditions for leasing the Potential Expansion Space within thirty
(30) days immediately following Tenant's receipt of Landlord's Expansion Notice,
or if having received Tenant's Expansion Notice, Landlord sends Tenant
Landlord's notice of its election not to deliver Landlord's Expansion Notice,
then Tenant may elect by written notice given within either such thirty day
periods (i) to pursue the issuance of the Permits and Approvals (provided that
Landlord's approval of the applicable plans, which shall not be unreasonably
withheld or delayed, is obtained prior to the submission of any such
application) at Tenant's sole cost and expense, and (ii) assuming the Permits
and Approvals are obtained and that the same are reasonably acceptable to both
Landlord and Tenant, to construct the Potential Expansion Space at Tenant's sole
cost and expense as an addition to the Building and pay for all permits,
licenses and fees associated therewith. In the event Tenant elects to perform
the construction of the Potential Expansion Space as described in the preceding
sentence, Landlord agrees that (i) it shall use all commercially reasonable
efforts to secure any necessary approvals from Landlord's mortgage lender(s) to
permit such construction, (ii) it shall cooperate (at no material cost to
Landlord, other than normal overhead and internal costs), as may be necessary as
the owner of the property, with the processing of any applications for Permits
and Approvals, and (iii) that from and after completion, the Potential Expansion
Space will be a part of the Premises and Tenant will be responsible for all
utility costs and other operating costs and taxes relating thereto, on the same
terms and conditions as are set forth in this Lease, but no additional Base Rent
will be due or payable on account of the construction of the Expansion Space by
Tenant. Tenant agrees and acknowledges that such Expansion Space improvements
shall become Landlord's property upon completion thereof and that any warranties
obtained in connection with such construction shall be assigned to Landlord upon
receipt thereof by Tenant. Tenant agrees and acknowledges that Landlord shall
have no liability to Tenant whatsoever if the Permits and Approvals for such
Potential Expansion Space are not obtained or if less than 40,000 rentable
square feet of expansion space is allowed, or if conditions are imposed in
connection with such Permits and Approvals which are unacceptable to Landlord,
Landlord's mortgagee(s) or Tenant. Tenant's first right of negotiation for the
Potential Expansion Space is personal to Tenant and may not be exercised,
voluntarily or involuntarily, by or to any person or entity other than Tenant.
Tenant may only exercise the right granted in this Section 11.1 if on the date
that Tenant delivers Tenant's Expansion Notice to Landlord; Tenant is not in
default under this Lease beyond the expiration of any applicable notice, grace
and cure periods which may be provided herein and (iii) Tenant shall not have
assigned this Lease or sublet the Premises (except for Permitted Transfers
pursuant to section 6.1.11).

                                      32
<PAGE>

     In connection with any election by Tenant to construct the Proposed
Expansion Space, Tenant's right to commence construction shall be subject to the
following conditions:

     (a)  Tenant shall have furnished Landlord and Landlord's mortgagee(s) with
satisfactory evidence that there is sufficient time for the Tenant to complete
construction of the Potential Expansion Space at lease one year prior to the
expiration of the then current term of the Lease;

     (b)  Tenant shall have furnished Landlord and Landlord's mortgagee(s) with
satisfactory evidence that during the term of such construction, the Lease will
remain in full force and effect and binding upon the Tenant without any right of
cancellation during the period of construction;

     (c)  Tenant shall have furnished Landlord and Landlord's mortgagee(s) with
satisfactory evidence that sufficient funds are available to cover all hard and
soft costs of completing the Potential Expansion Space;

     (d)  Landlord and Landlord's mortgagee(s) shall have reviewed and approved
the plans and specifications, the identity of the Architect and the form and
substance of the Architect's Contract, the identity of the General Contractor
and the form and substance of the Construction Contract (including, without
limitation, the posting of performance payment and lien bonds in form and
substance and issued by a surety acceptable to Landlord and Landlord's
mortgagee(s));

     (e)  Tenant shall have furnished Landlord and Landlord's mortgagee(s) with
satisfactory evidence that all Permits and Approvals necessary for the
construction and operation of the Potential Expansion Space have been obtained,
all in form and substance and subject to conditions satisfactory to Landlord and
Landlord's mortgagee(s).

     (f)  Tenant shall have furnished Landlord and Landlord's mortgagee(s) with
satisfactory evidence that Tenant will pay any third party cost reasonably
incurred by Landlord and Landlord's mortgagee in connection with documenting and
reviewing matters relating to the Potential Expansion. space.

     Tenant's construction of the Potential Expansion space shall be performed
in a good and workmanlike manner, shall be to a level of quality at least equal
to the level of quality of the existing Premises, and in compliance with all
laws, rules and regulations. Following completion of the Potential Expansion
Space, Tenant shall be solely responsible for the cost of maintaining, repairing
and replacing the same for the balance of the term of this Lease.


                                 ARTICLE XII.
                                 ------------
                        Index of Certain Defined Terms
                        ------------------------------

Term                                           Where Defined
----                                           -------------

                                      33
<PAGE>

Annual Base Rent - Extension Terms             1.1; 4.1.2
Annual Base Rent - Initial Term                1.1; 4.1.1
Building                                       1.1
Commencement Date                              1.1
Construction Documents                         3.2.2
Date of Lease Execution                        1.1
Existing Tenant                                2.2
Extension Term                                 1.1; 2.5
Fair Market Rent                               4.1.2
Hazardous materials                            6.1.8
Hazardous materials activities                 6.1.8
Indemnitees                                    6.1.5
Landlord                                       1.1
Landlord's Agent                               1.1
Landlord's Taxes                               4.3.2
laws                                           6.1.3
Lease year                                     4.2
mortgage                                       10.1
mortgagee                                      10.1
Original Address of Landlord                   1.1
Original Address of Tenant                     1.1
Permitted Uses                                 1.1
Premises                                       1.1; 1.2
Public Liability Insurance                     1.1
Security Deposit                               1.1; 9.11

                                      34
<PAGE>

          Tenant                                         1.1
          Tenant's Architect                             3.2.2
          Tenant Contractor                              3.2.3
          Tenant Work                                    3.2
          Term                                           1.1; 2.4
          Transfer                                       6.1.11

   ----------------------------Here ends page 34--------------------------
                            signatures on next page

                                      35
<PAGE>

                               SIGNATURE PAGE TO
          LEASE BETWEEN APPLIED SCIENCE AND TECHNOLOGY, INC., Tenant
               AND NINETY INDUSTRIAL WAY WILMINGTON LLC, Landlord



Executed under seal as of the date first written above.



TENANT:                                  LANDLORD:
------                                   --------

APPLIED SCIENCE AND TECHNOLOGY,          NINETY INDUSTRIAL WAY
INC, a Delaware corporation              WILMINGTON LLC, a
                                         Massachusetts limited liability
                                         company

By: /s/ Richard S. Post                  By: /s/ John A. Thomas, Manager
   --------------------                      ---------------------------
   President                                 John A. Thomas, Its Manager


By: /s/ John M. Tarrh                    By: /s/ David T. Ting
   ------------------                        -----------------
   Treasurer                                 David T. Ting, Its Manager

                                      36
<PAGE>

                                   EXHIBIT B


                                Lot Description
                                ---------------

                                      37
<PAGE>

                                   EXHIBIT B



That certain parcel of land, situated in Wilmington, Middlesex County,
Massachusetts, shown as Lot 23 on a plan entitled, "Plan of Land in WILMINGTON,
MASS., Owned By- I. Fred & Carlo B. DiCenso, Scale 100 feet to an inch - May 5,
1977, Robert E. Anderson Inc., Reg. Professional Engineer; Reg. Land Surveyors,
178 Park Street, North Reading, Mass.," filed with Middlesex North District
Registry of Deeds in Plan Book 124, Page 69, said parcel being bounded and
described, according to said plan, as follows:

BEGINNTNG at the northeasterly corner of said parcel at land of Frederick
Sheehan at a point in the westerly sideline of West Street; THENCE running by
West Street

SOUTHEASTERLY, by two lines measuring, respectively, 228.04 feet and 18.26 feet
to land of I. Fred & Carlo B. DiCenso; THENCE running by the land last named.

WESTERLY, by seven lines measuring, respectively, 65.53 feet, 212.29 feet,
107.74 feet, 210.26 feet, 270.94 feet, 186.28 feet, and 387.45 feet; THENCE by
running by said land last named

NORTHERLY, by a single line measuring 344.03 feet, to the land of John James &
Thomas Lyons; and THENCE running by said land of John James & Thomas Lyons and
land of Frederick Sheehan

EASTERLY, by seven lines measuring, respectively, 270.00 feet, 231.72 feet,
198.21 feet, 155.36 feet, 162.50 feet, 99.59 feet, and 194.68 feet to the point
of BEGINNING.

Said Lot 23 containing 9.2895 acres, according to said plan, be said contents
measured more or less.

Included in the above described parcel is the registered land shown as Lot 22 on
a plan entitled "Land Court Subdivision Plan of Land in Wilmington, Mass.,"
scale 100 feet to an inch, dated March 15, 1977, by Robert E. Anderson Inc.,
Reg. Professional Engineer, Reg. Land Surveyor, 178 Park Street, North Reading,
Mass., filed with the Land Court as Plan No. 33467N.

AREA AA (REGISTERED LAND)

That strip of land situated in Wilmington, Middlesex County, Massachusetts,
shown as "Access and Utility Easement in Common with Abuttors Variable Width" on
the Registered Plan filed with the Land Court as Plan No. 3346714 and on the
Unregistered Plan described hereinabove.

          Said snip of land being a portion of Lot 21 as shown on the Land Court
Plan No. 33467N.

AREA BB (UNREGISTERED)

                                      38
<PAGE>

          That strip of land situated in Wilmington, Middlesex County,
          Massachusetts shown as "Access & Utility Easement in Common with
          Others" on the Unregistered Plan, recorded in Plan Book 124, Plan #69,
          bounded and described as follows:

          BEGINNING at a point in the northwesterly sideline of Industrial Way
          located S 2 (degrees) 17'16" W of and 534.10 feet distant from the
          northwesterly corner of Lot 11 shown on Land Court Plan 33467-F;

          Thence running along northwesterly sideline of Industrial Way.

          Southwesterly by a curve to the left (with a radius of 677.22 feet) an
          arc distance of 8.26 feet and S 54 (degrees) 34'40" W 91.74 feet to
          land now or formerly of I. Fred DiCenso et al (in part shown as Lot 16
          on Land Court Plan No. 33467J);

          Thence running by the Land last named; N 02 (degrees) 07'16" E, 295.03
          feet, to Lot 21 on Land Court Plan No. 33467 N;

          Thence running by said Lot 21, N 89 (degrees) 14'34" E, 79.42 feet;

          Thence running 5 02 (degrees) 07'16" W 238.12 feet, to the Point of
          Beginning.

Together with the easement and right to use, in common with others entitled
thereto, as appurtenant to the aforementioned parcel and any part or parts
thereof, the premises described hereinafter as Areas AA and BB, for all purposes
for which streets and ways are now or may hereafter be used in the Town of
Wilmington, including the use, installation, maintenance, repair, servicing, and
replacement of any and all underground lines and utilities of any type, kind or
nature, including, without limitation, water, gas, electricity, sewers, drains
and pipelines, except for above ground utility lines, pipes, poles and wires,
and except that the owner or owners from time to time of the land to which such
right and easement are appurtenant may not connect to and make use of any
utility lines (including without limiting the generality of the foregoing, water
supply pipes, gas pipes, sanitary sewers, and storm drains) now existing or
hereafter installed in said Areas AA and BB, or either of them, by the owner of
the fee title to such Areas or others entitled to similar rights and easements
therein and will repair any damage to the same arising from its exercise of the
right and easement hereby granted. Said right and easement hereby granted shall
be subject, however, to the obligation of the party exercising the right and
easement hereby granted (1) to comply with applicable laws; (2) to restore the
portions of the Areas affected thereby as near as reasonably practicable to the
condition thereof existing prior to such installation, repair, maintenance,
servicing or replacement, consistent with the exercise of the right and easement
herein granted; and (3) to hold the Grantors, their heirs, administrators,
successors, or assigns, harmless against any liability incurred by the Grantors
their heirs, administrators, successors, or assigns, resulting from such use,
installation, maintenance, servicing, repair or replacement by such party.

                                      39
<PAGE>

                                   EXHIBIT C


                        Tenant Work Insurance Schedule
                        ------------------------------

     1.   Tenant shall purchase or shall cause each Tenant Contractor to
purchase, in a company or companies against which the Landlord has no reasonable
objection, such insurance as will protect him from claims set forth below which
may arise out of or result from the contractor's operations on the Premises.

          1.1       claims under workers' or workmen's compensation, disability
benefit and other similar employee benefit acts;

          1.2       claims for damages because of bodily injury, occupational
sickness or disease, or death of his employees;

          1.3       claims for damages because of bodily injury, sickness or
disease, or death of any person other than his employees;

          1.4       claims for damages insured by personal injury liability
coverage which are sustained (1) by any person as a result of an offense
directly or indirectly related to the employment of such person by the
Contractor, or (2) by any other person;

          1.5       claims for damages, other than the Tenant work itself,
because of injury to or destruction of tangible property, including loss of use
resulting therefrom;

          1.6       claims for damages insured by personal injury or death of
any person or property damage arising out of the ownership, maintenance or use
of any motor vehicle; and

          1.7       claims for contractual liability (both oral and written)
under this undertaking with Tenant.

     2.   The insurance required by Section 1 of this Schedule shall include all
major divisions of coverage, and shall be on a comprehensive general basis. Such
insurance shall be written for not less than any limited of liability required
by law or those set forth below, whichever is greater.

          2.1       Workmen's Compensation - as required by law.

          2.2       Public Liability - single Limit (Combined) per Occurrence.

                    Bodily & Personal Injury $1,000,000
                    Property Damage $1,000,000 Occurrence/Aggregate.

                                      40
<PAGE>

                           FIRST AMENDMENT TO LEASE
                           ------------------------

     FIRST AMENDMENT TO LEASE (the "Amendment") is entered into as of the 1st
day of October, 1999, by and between NINETY INDUSTRIAL WAY WILMINGTON LLC, a
Massachusetts limited liability company with an address do Brownfields Recovery
Corp., 222 Berkeley Street, Boston, Massachusetts 02116 ("Landlord"), and
APPLIED SCIENCE AND TECHNOLOGY, INC., a Delaware corporation with an address of
35 Cabot Road, Woburn, Massachusetts 01801 ("Tenant").

                             W I T N E S S E T H:

     WHEREAS, Landlord and Tenant entered into that certain Lease dated as of
May 21, 1999 (the "Astex Lease"); and

     WHEREAS, Tenant has requested the ability to occupy a portion of the
Premises (as defined in the Astex Lease) prior to the Commencement Date (as
defined in the Astex Lease), and, subject to the terms and conditions set forth
herein, Landlord has agreed to permit such occupancy.

     NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, Landlord and Tenant hereby agree
to amend the Astex Lease as follows:

     1.   Occupied Space.  A portion of the Premises consisting of approximately
          --------------
10,000 square feet located on the first floor of the Building (as defined in the
Astex Lease) and outlined on Exhibit A attached hereto is hereby designated the
"Occupied Space".

     2.   Permitted Uses.  The Occupied Space may be used for any use permitted
          --------------
under the Lease.

     3.   Commencement Date.  Notwithstanding the provisions of the Lease to the
          -----------------
contrary, the Commencement Date and Rent Commencement Date for the Occupied
Space shall be October 1, 1999 (the "Early Occupancy Date").

     4.   Rent.  From and after the Early Occupancy Date through the Rent
          ----
Commencement Date for the Premises as set forth in the Lease (the "Early
Occupancy Period"), Tenant shall pay Rent to Landlord in the amount of $87,500
per year. Rent shall be payable in advance in equal monthly installments of
$7291.67 by the first day of each calendar month during the Early Occupancy
Period.

     5.   Additional Rent.  In addition to the foregoing Rent, during the
          ---------------
remaining term of the lease dated February 5, 1999 by and between Ninety
Industrial Way Wilmington LLC and AGFA Corporation ("AGFA") (the AGFA Lease"),
Tenant shall pay to AGFA, on the first day of each calendar month. Tenant's pro
rata share of the Landlord's Taxes and pro rata share of Utilities, Maintenance,
Repairs and Improvements in the amount of $6,983.00 per month ("Additional
Rent"). Landlord acknowledges that, during the remaining term of the AGFA
<PAGE>

Lease, so long as Astex makes the payments specified above to AGFA, then
Landlord's recourse for such payments shall be against AGFA and not Astex.

     After the termination or expiration of the AGFA Lease and until the
Commencement Date occurs pursuant to the Astex Lease, Tenant shall pay to
Landlord Tenant's pro rata share of the Landlord's Taxes and the Additional
Rent.

     Upon the occurrence of the Commencement Date pursuant to the Astex Lease,
in addition to the Rent specified above for the Early Occupancy Period, Tenant
shall commence payments of Additional Rent pursuant to Section 4.3 of the Astex
Lease with respect to the entire Premises, including the Office Space. Upon the
occurrence of the Rent Commencement Date pursuant to the Astex Lease, Tenant
shall commence paying the Annual Base Rent - Initial Term specified in the Astex
Lease, together with the Additional Rent, for the entire Premises and shall
cease paying the Rent and Additional Rent specified above for the Early
Occupancy Period.

     6.   Applicability of Lease Provisions; Continued Effectiveness. Except as
          ----------------------------------------------------------
specifically set forth herein, the Lease remains unmodified and in full force
and effect and shall be applicable to Tenant's occupancy of the Occupied Space
during the Early Occupancy Period. Solely for purposes of the applicability of
the Lease during the Early Occupancy Period, all references to "Premises" in the
Lease shall be deemed to refer to the "Occupied Space".

                         [Signatures begin next page]

                                       2
<PAGE>

     IN WITNESS WHEREOF, the parties have caused this Amendment to be executed
as an instrument under seal as the date first above written.

                              LANDLORD:

                              NINETY INDUSTRIAL WAY
                              WILMINGTON LLC,
                              a Massachusetts limited liability company

                              By: /s/ John A. Thomas, member
                                 -------------------------------------
                                      Name: John A. Thomas, member

                              By: /s/ David T. Ting
                                 -------------------------------------
                                      Name David T. Ting, member


                              TENANT:

                              APPLIED SCIENCE AND TECHNOLOGY, INC.
                              a Delaware corporation


                              By: /s/ John M. Tarrh
                                 -------------------------------------
                              Name:  John M. Tarrh
                                   -----------------------------------
                              Title: Senior Vice President
                                     ---------------------------------
                              Hereunto duly authorized

                                       3