<PAGE>

                                                                   Exhibit 10.10

                   CONSENT OF LANDLORD TO PROPOSED SUBLEASE


     Subject to the conditions set forth this Consent of Landlord to Proposed
Sublease ("Consent"), SQUARE 24 ASSOCIATES ("Landlord") hereby consents to that
           -------                           --------
certain Sublease attached hereto, dated May 30, 2000, between LATTICE
SEMICONDUCTOR CORPORATION, a Delaware corporation ("Sublessor") and VITRIA
                                                    ---------
TECHNOLOGY, INC. a California corporation ("Sublessee"), and all its terms (the
                                            ---------
"Sublease"). This Consent does not release or discharge either Advanced Micro
 --------
Devices, Inc. ("AMD") or Sublessor from any liability as lessee under that
                ---
certain Lease dated September 17, 1997, between Landlord's predecessor in
interest, Stewart Drive, L.L.C., as landlord, and AMD, as tenant (the "Lease").
                                                                       -----
Pursuant to that certain Lease Assignment and Assumption Agreement dated June
15, 1999, all of AMD's rights, title and interest in the Lease were assigned to
and assumed by Sublessor's predecessor in interest, Vantis Corporation

("Vantis"). Pursuant to that certain Assignment of Lease dated April 30, 2000,
  ------
by and among Landlord, Vantis and Sublessor, all of Vantis' rights, title and
interest in the Lease were further assigned to and assumed by Sublessor, and
Landlord agreed to release Vantis from any further liability under the Lease.
This Consent is granted by Landlord subject to the following terms and
conditions:

     1.  Unless expressly permitted under the Lease, Sublessee shall not assign
the Sublease nor sublet the premises described in the Sublease (the "Subleased
                                                                     ---------
Premises") in whole or part; and shall not permit Sublessee's interest in the
--------
Sublease to be vested in any third party by operation of law or otherwise,
without Landlord's prior written consent, which consent shall not be
unreasonably withheld.

     2.  This Consent shall not be deemed to be a consent to any subsequent
assignment or subletting. Sublessor shall not make any subsequent amendment to
the Sublease without Landlord's prior written consent, which consent shall not
be unreasonably withheld. Landlord shall not be deemed to have waived any rights
under the Lease by virtue of this Consent.

     3.  The Sublease is in all respects subordinate to the terms of the Lease.
Insofar as the specific terms of the Sublease purport to amend or modify or are
in conflict with the specific terms of the Lease, the terms of the Lease shall
control. Except as expressly set forth in this Consent, Landlord assumes no
liability whatsoever on account of anything contained in the Sublease.

     4.  Any rights under the Sublease may be enforced only against Sublessor,
and Sublessee shall have no right to enforce any of Sublessor's rights under the
Lease against Landlord by virtue of the Sublease, this Consent, or otherwise.

     5.  Pursuant to Section 6.E of the Lease, AMD (or Sublessor) shall pay in
addition to all other amounts due Landlord under the Lease (including the excess
rent required to be paid to Landlord pursuant to Section 6.F of the Lease), the
reasonable costs (including attorneys' fees) incurred by Landlord in connection
with the review of the Sublease and the processing of this Consent thereto.
<PAGE>

     6.  Notwithstanding any provision in the Sublease to the contrary,
Sublessee shall not have any rights under Sections 37 (Extension Option) or 38
(Right of First Offer) of the Lease.

     7.  Notwithstanding any provision in the Sublease (including Section 10
thereof) to the contrary, the Sublease shall automatically terminate upon the
termination of the Lease for any reason.

     8.  Subject to Sublessee's agreement in Section 11.A(viii) of the Sublease
to have the waiver of subrogation provisions of Section 11.K of the Lease also
apply as between Landlord and Sublessee, Landlord agrees that the waiver of
subrogation provisions set forth in Section 11.K of the Lease shall also apply
as between Landlord and Sublessee.

     9.  Landlord agrees that a courtesy copy of any formal notice sent by
Landlord to AMD under the Lease (excluding those sent pursuant to Section 38)
shall be sent to 555 NE Moore Court, Hillsborough, Oregon, 97124, Attention:
General Counsel.

     IN WITNESS WHEREOF, the undersigned has executed this Consent on behalf of
Landlord as of May 30, 2000.

                    LANDLORD:
                    SQUARE 24 ASSOCIATES L.P. (d.b.a. Square 24 Associates)
                    a District of Columbia limited partnership
                         By:  Carr Real Estate Services, L.L.C.,
                              a Delaware limited liability company
                         Its: General Partner
                              By:  Carr Real Estate Services Partnership,
                                   a Delaware partnership
                              Its: Managing Partner
                                   By:  Carr Realty, L.P.,
                                        a Delaware limited partnership
                                   Its: Managing Partner
                                        By:  CarrAmerica Realty Corporation,
                                             a Maryland corporation
                                        Its: General Partner

                                             By: /s/ Leah N. Segawa
                                                 ------------------
                                                  Leah N. Segawa
                                             Its: Managing Director
                               Date of Execution: 5/30/2000
                                                  -----------------
<PAGE>

                                   SUBLEASE
                                   --------

     THIS SUBLEASE (this "Sublease") is dated for reference purposes only as of
May 30, 2000 (the "Effective Date"), and is made by and between Lattice
Semiconductor Corporation, a Delaware corporation ("Sublandlord"), and Vitria
Technology, a Delaware corporation ("Subtenant"). Sublandlord and Subtenant
hereby agree as follows:

     1.  Recitals: This Sublease is made with reference to the following facts
         --------
and objectives:

          A.  Stewart Drive, L.L.C., a California limited liability company
("Master Landlord") and Advanced Micro Devices, Inc., a Delaware corporation
("AMD"), as tenant, entered into that certain lease dated as of September 17,
1997 (the "Master Lease"), with respect to premises consisting of approximately
83,950 rentable square feet of space in the 995 Building and the 985 Building
(with the 995 Building consisting of approximately 42,064 rentable square and
the 985 Building consisting of approximately 41,886 rentable square feet), which
Premises are commonly known as 995 Stewart Drive, Sunnyvale, California (the
"995 Building"), and 985 Stewart Drive, Sunnyvale, California (the "985
Building"). A true, complete and correct copy of the Master Lease, which
includes all exhibits, addenda, and amendments thereto, is attached hereto as
Exhibit A.
---------

          B.  AMD assigned its interest in the Master Lease to Vantis
Corporation by a Lease Assignment and Assumption Agreement dated June 15, 1999.
Vantis Corporation has assigned its interest in the Master Lease to Sublandlord
by an Assignment of Lease dated as of April 30, 2000, such that Sublandlord is
now the tenant under the Master Lease.

          C.  Sublandlord desires to sublease the Premises to Subtenant, and
Subtenant desires to sublease the Premises from Sublandlord, on the terms and
conditions set forth in this Sublease.

     2.  Definitions: Terms given specific meanings by this Sublease shall have
         -----------
the meanings so ascribed to them. Except as otherwise specifically indicated,
capitalized terms that are given specific definitions by the Master Lease are
used herein with the meanings ascribed to them by the Master Lease.

     3.  Premises: Sublandlord hereby subleases to Subtenant, and Subtenant
         --------
hereby subleases from Sublandlord, the Premises for the Term. Sublandlord hereby
grants to Subtenant for the Term the same rights to use the Outside Areas of the
Project as are granted to Sublandlord pursuant to the Master Lease.

     4.  Term:
         ----

          A.  Term. The term (the "Term") of this Sublease shall be for the
              ----
period commencing on the "Delivery Date" (as defined herein) and ending on April
30, 2006 (the "Expiration Date"), unless this Sublease is sooner terminated
pursuant to its terms or the Master Lease is sooner terminated pursuant to its
terms.

                                      -1-
<PAGE>

          B.  Delivery of Possession. The parties acknowledge that Sublandlord
              ----------------------
is planning to move its business operations, personnel and property located at
the Premises to other buildings currently under construction located at
2660/2680 Zanker Road, San Jose, California (the "Replacement Premises"). As
soon as practicable after construction of the Replacement Premises has been
completed and the Replacement Premises are ready for Sublandlord's occupancy,
Sublandlord shall commence and diligently prosecute to completion the process of
moving its business operations now located at the Premises to the Replacement
Premises. It is anticipated that this moving process will be completed during
the last two weeks of June, 2000. As soon as reasonably practicable following
the date that Sublandlord has removed from the Premises all of its personnel and
substantially all of its equipment, furnishings, and personal property,
Sublandlord shall deliver possession of the Premises to Subtenant, and
thereafter Subtenant may begin the process of preparing the Premises for
Subtenant's occupancy and the commencement of Subtenant's business operations;
provided, however, that on the date of such delivery of possession, Landlord
shall not be obligated to have completed the process of putting the Premises in
"broom clean" condition or other repair or maintenance work Sublandlord is
required to undertake which does not materially interfere with Subtenant's work
to prepare the Premises for Subtenant's occupancy. The date upon which
Sublandlord so delivers possession of the Premises to Subtenant is referred to
herein as the "Delivery Date". During the thirty (30) days following the
Delivery Date, Sublandlord and Subtenant shall work cooperatively to coordinate
their respective construction, clean-up, and move-in activities so that neither
interferes with the activity of the other and that all work required of
Sublandlord is completed by the end of such thirty (30) day period.

          C.  Commencement of Tenant's Sublease Obligations. The Term of this
              ---------------------------------------------
Sublease shall commence on the Delivery Date, and all of Subtenant's obligations
under this Sublease shall also commence as of the Delivery Date, including
without limitation the obligation to pay Additional Rent; provided, however,
that as specified in Section 5A hereof, Subtenant's obligation to pay Base Rent
shall not commence until the thirtieth (30th) day following the Delivery Date
(which day is referred to herein as the "Sublease Rent Commencement Date").

          D.  No Option to Extend. The parties hereby acknowledge that the
              -------------------
Expiration Date of the Master Lease is April 30, 2006 and that Subtenant has no
option to extend the Term of this Sublease.

          E.  Delay of Possession: If the Delivery Date has not occurred by
              -------------------
October 31, 2000, due to Sublandlord's failure diligently to move its business
operations now located at the Premises to the Replacement Premises, then
Subtenant shall have the right to terminate this Sublease by giving Sublandlord
written notice of such termination no later than January 10, 2001. Except as
expressly provided in this paragraph, no delay in Sublandlord's delivery of
possession of the Premises to Subtenant shall give Subtenant any rights or
remedies whatsoever, and no such delay in delivering the Premises shall in any
event extend the Term of this Sublease.

     5.  Rent:
         ----

          A.  Subtenant shall pay to Sublandlord as base monthly rent for the
Premises the following amounts during the indicated periods (the "Base Rent"):

                                      -2-
<PAGE>

               (i)   For the annual period commencing on the Sublease Rent
Commencement Date, the Base Rent shall be Two Hundred Fifty-One Thousand Eight
Hundred Fifty Dollars ($251,850) per month.

               (ii)  For the annual period commencing on the first (1/st/)
anniversary of the Sublease Rent Commencement Date, the Base Rent shall be Two
Hundred Fifty-Nine Thousand Four Hundred Six Dollars ($259,406) per month.

               (iii) For the annual period commencing on the second (2/nd/)
anniversary of the Sublease Rent Commencement Date, the Base Rent shall be Two
Hundred Sixty-Seven Thousand One Hundred Eighty-Eight Dollars ($267,188) per
month.

               (iv)  For the annual period commencing on the third (3/rd/)
anniversary of the Sublease Rent Commencement Date, the Base Rent shall be Two
Hundred Seventy-Five Thousand Two Hundred Three Dollars ($275,203) per month.

               (v)   For the annual period commencing on the fourth (4/th/)
anniversary of the Sublease Rent Commencement Date, the Base Rent shall be Two
Hundred Eighty-Three Thousand Four Hundred Fifty-Nine Dollars ($283,459) per
month.

               (vi)  For the period commencing on the fifth (5/th/) anniversary
of the Sublease Rent Commencement Date, and continuing until the Expiration
Date, the Base Rent shall be Two Hundred Ninety-One Thousand Nine Hundred Sixty-
Three Dollars ($291,963) per month.

          B.  Payment of Base Rent and Additional Rent, as defined in Section
5.C below, shall be paid on or before the first (1st) day of each month. Base
Rent and Additional Rent for any period during the Term hereof which is for less
than one (1) calendar month of the Term shall be a pro rata portion of the
monthly installment based on a thirty (30) day month. Base Rent and Additional
Rent shall be payable without notice or demand and without any deduction,
offset, or abatement, in lawful money of the United States of America. Base Rent
and Additional Rent shall be paid directly to Sublandlord at 5555 NE Moore
Court, Hillsborough, Oregon, 97124, Attention: Accounts Receivable, or such
other address as may be designated in writing by Sublandlord.

          C.  Additional Rent. All monies other than Base Rent required to be
              ---------------
paid by Subtenant under this Sublease, including, without limitation, any
amounts payable by Sublandlord to the Master Landlord as "Additional Rent" (as
defined in Paragraph 3B of the Master Lease), shall be deemed additional rent to
be paid by Subtenant ("Additional Rent"). Base Rent and Additional Rent
hereinafter collectively shall be referred to as "Rent". All amounts payable by
Sublandlord to the Master Landlord as "Additional Rent" (as defined in Paragraph
3B of the Master Lease) are referred to herein as "Master Lease Additional
Rent". Subtenant shall pay all Master Lease Additional Rent as and when the same
are due and payable to the Master Landlord under the Master Lease. Subtenant
shall be entitled to all credits, if any, given by the Master Landlord to
Sublandlord for Sublandlord's overpayment of Master Lease Additional Rent to the
extent such overpayment is fairly allocable to Master Lease Additional Rent
accruing during the Term of this Sublease. Subtenant shall not be required to
pay any Master Lease Additional Rent that is (i) fairly allocable to any period
of time prior to the Delivery Date or after the Expiration Date, or (ii) payable
solely as a result of a

                                      -3-
<PAGE>

default by Sublandlord under the Master Lease, which default is not the result
of any failure of Subtenant to fully and timely observe, perform and discharge
all obligations imposed on Subtenant by this Sublease (including, without
limitation, the obligation of Subtenant, at Subtenant's sole cost, fully to
restore the Premises and otherwise surrender the Premises in the condition
required by the Master Lease).

          D.  Payment of First Month's Rent. Upon execution hereof by Subtenant,
              -----------------------------
Subtenant shall pay to Sublandlord the sum of Two Hundred Fifty-One Thousand
Eight Hundred Twelve Dollars ($251,812), which shall constitute Base Rent for
the first month of the Term during which Base Rent is due.

     6.  Security Deposit:
         ----------------

          A.  On the Effective Date, Subtenant shall deposit with Sublandlord
the amount of Fifteen Million Dollars ($15,000,000) as security for the
performance by Subtenant of its obligations under this Sublease, and not as
prepayment of rent (the "Security Deposit"). Sublandlord may from time to time
apply such portion of the Security Deposit as is reasonably necessary for the
following purposes: (i) to cure any default by Subtenant in the payment of Rent;
(ii) to repair damage to the Premises caused by Subtenant; (iii) to clean the
Premises upon termination of the Sublease, if necessary; and (iv) to remedy any
other default of Subtenant and/or to pay damages resulting from Subtenant's
default to the extent permitted by applicable law and, in this regard, Subtenant
hereby waives (to the extent permitted by applicable law) any restriction on the
uses to which the Security Deposit may be put contained in California Civil Code
Section 1950.7. In the event the Security Deposit or any portion thereof is so
used, Subtenant agrees to pay to Sublandlord promptly upon demand an amount in
cash sufficient to restore the Security Deposit to the full original amount.
Sublandlord shall not be deemed a trustee of the Security Deposit, may use the
Security Deposit in its business, and shall not be required to segregate it from
its general accounts. Subtenant shall not be entitled to any interest on the
Security Deposit. If Sublandlord transfers the Premises during the Lease Term,
Sublandlord shall transfer the Security Deposit to any transferee of
Sublandlord's interest in conformity with the provisions of California Civil
Code Section 1950.7 and/or any successor statute, whereupon the transferring
Sublandlord will be released from all liability for the return of the Security
Deposit.

          B.  Subtenant shall satisfy its obligation to deposit the Security
Deposit with Sublandlord by delivering to Sublandlord on the Effective Date an
unconditional, irrevocable, transferable letter of credit in the amount of
Fifteen Million Dollars ($15,000,000), issued by a financial institution
acceptable to Sublandlord in the form attached hereto as Exhibit B, with an
                                                         -----------
original term of no less than one (1) year and automatic extensions through the
end of the Term of this Sublease and sixty (60) days thereafter (the "Letter of
Credit"). Subtenant shall keep the Letter of Credit, at its expense, in full
force and effect until the sixtieth (60/th/) day after the Expiration Date, or
other termination of this Sublease. The Letter of Credit shall provide thirty
(30) days' prior written notice to Sublandlord of cancellation or material
change thereof, and shall further provide that, in the event of any such notice
cancellation or material change of the Letter of Credit or any non-extension of
the Letter of Credit at least thirty (30) days prior to its expiration,
Sublandlord shall be entitled to draw the entire face amount of the Letter of
Credit, and the funds so obtained shall be held as the Security Deposit. Any
unused portion of the funds so obtained by Sublandlord shall be

                                      -4-
<PAGE>

returned to Subtenant upon replacement of the Letter of Credit or deposit of
cash security in the full amount of the required Security Deposit.

          C.  In lieu of, or in replacement of, the Letter of Credit, Subtenant
may deliver to Sublandlord at any time during the Term a cash deposit in the
face amount required for the Security Deposit, provided that Sublandlord shall
have no additional liability or reduced benefits from that which Sublandlord
would have if Subtenant provided a Letter of Credit.

          D.  On each January 1, April 1, July 1, and October 1 during the Term
of this Sublease (each a "Security Adjustment Date"), Subtenant shall have the
right to cause the amount of the Security Deposit (or the face amount of the
Letter of Credit) to be reduced to an amount that equals the sum of the
following: (i) the aggregate amount of all monthly Base Rent that is due for the
then remainder of the Term of the Sublease (not discounted to present value);
and (ii) the Restoration Cost (as defined herein), as reasonably determined by
Sublandlord. If on a Security Adjustment Date Subtenant qualifies for a
reduction in the amount of the Security Deposit and elects to exercise its right
to cause the Security Deposit to be reduced, Subtenant shall notify Sublandlord
of its election within ten (10) days after the applicable Security Adjustment
Date. Within five (5) days after receipt of such notice, and if Subtenant is
entitled to the reduction sought, Sublandlord shall either (a) if the Security
Deposit is in the form of cash, return to Subtenant the appropriate amount so
that the remaining amount held by Sublandlord as the Security Deposit is in the
correct amount after the permitted reduction, or (b) if the Security Deposit is
held in the form of a Letter of Credit, Sublandlord shall return such Letter of
Credit and any cash held as the Security Deposit to Subtenant when Subtenant
delivers to Sublandlord a new Letter of Credit meeting the requirements set
forth in Section 6.B hereof, the face amount of which is the correct amount of
the Security Deposit, after implementing the appropriate reduction permitted by
this Section 6.D. Notwithstanding anything contained herein, Sublandlord shall
not be obligated to implement a reduction of the Security Deposit if Subtenant
is then in default of any of its obligations under this Sublease beyond any
applicable notice and cure periods. If Subtenant is in default (beyond
applicable notice and cure periods) as of any Security Adjustment Date and does
not therefore qualify for a reduction in the amount of the Security Deposit, but
Subtenant thereafter cures such default in a manner reasonably acceptable to
Sublandlord and pays Sublandlord all damages suffered by Sublandlord as a result
of such default (including, without limitation, any resulting late charges and
interest payable under this Sublease) (a "Cure"), then Subtenant shall have the
right to cause the Security Deposit to be reduced by the amount of the reduction
that would otherwise have been available to Subtenant had Subtenant not been in
default as of such Security Adjustment Date. If Subtenant qualifies for such a
reduction in the amount of the Security Deposit and elects to exercise its right
to cause the Security Deposit to be reduced, Subtenant shall notify Sublandlord
of its election within ten (10) days after the Cure of such default. Within five
(5) days after receipt of such notice, and if Subtenant is both entitled to the
reduction sought and is not then in default under any other obligation under
this Sublease (beyond applicable notice and cure periods), then Sublandlord
shall reduce the Security Deposit in the manner provided either in the foregoing
clause (a) or (b) of this paragraph.

          E.  As used herein, the term "Restoration Cost" shall mean the
estimated cost at the Expiration Date of causing to be performed Subtenant's
obligation to restore the Premises to the condition required by this Sublease,
as reasonably estimated by Sublandlord. The Restoration Cost will be reasonably
determined by Sublandlord when Sublandlord approves (or receives notice of

                                      -5-
<PAGE>

those Alterations not requiring Sublandlord's approval) any Alterations that
Subtenant intends to install in the Premises which Sublandlord requires to be
removed upon expiration of the Term or which otherwise are required to be
removed at the expiration of the Term in accordance with this Sublease.
Sublandlord's determination of the Restoration Cost shall be based upon the cost
that Sublandlord would incur if it were to be responsible for the performance of
Subtenant's obligation to restore the Premises, including without limitation
costs related to labor and materials, contractors' overhead and profit, permit
fees and taxes, commercially reasonable builder's risk insurance, and a
supervision fee in the amount of ten percent (10%) of all other costs included
in the Restoration Cost.

     7.  Delivery of Possession; Condition:  Sublandlord shall deliver the
         ---------------------------------
Premises to Subtenant in "broom clean" condition. Sublandlord shall remove its
signage and personal property from the Premises and repair any damage caused by
such removal. In addition, Sublandlord shall use commercially reasonable efforts
(not including the payment of any money or the incurring of any liabilities) to
permit Subtenant's re-use of all existing cabling and security systems located
within the Premises. Subtenant shall not, however, have the right to use, and
Subtenant acknowledges that Sublandlord may remove, any leased equipment (such
as the telephone switch currently serving the Premises), any re-usable, movable
security equipment, and any conduit currently connecting the Premises to any
other properties. Subtenant shall have the right to use any conduit currently
connecting the 985 Building to the 995 Building, but Sublandlord makes no
representation or warranty whatsoever regarding such conduit (including, without
limitation, as to the existence or condition of any such conduit). To
Sublandlord's actual knowledge, the plumbing, electrical, and heating,
ventilating and air conditioning systems serving the Premises will be in good,
working order and repair as of the Delivery Date. The parties acknowledge and
agree that Subtenant is subleasing the Premises on an "as is" basis, and that
Sublandlord has made no representations or warranties with respect to the
condition of the Premises as of the Delivery Date except as set forth in this
Section. Sublandlord shall have no obligation whatsoever to make or pay the cost
of any alterations, improvements or repairs to the Premises, including, without
limitation, any improvement or repair required to comply with any law,
regulation, building code or ordinance (including the Americans with
Disabilities Act of 1990).

     8.  Right to Cure Defaults:  If Subtenant fails to pay any sum of money to
         ----------------------
Sublandlord, or fails to perform any other act on its part to be performed
hereunder, then Sublandlord may, but shall not be obligated to, after passage of
any applicable notice and cure periods, make such payment or perform such act.
All such sums paid, and all reasonable costs and expenses of performing any such
act, shall be deemed Additional Rent payable by Subtenant to Sublandlord upon
demand, together with interest thereon at the Interest Rate from the date of the
expenditure until repaid.

     9.  Effect of Conveyance:  As used in this Sublease, the term "Sublandlord"
         --------------------
means the holder of the tenant's interest under the Master Lease. In the event
of any assignment, transfer or termination of the tenant's interest under the
Master Lease, which assignment, transfer or termination may occur at any time
during the Term hereof in Sublandlord's sole discretion, Sublandlord shall be
and hereby is entirely relieved of all covenants and obligations of Sublandlord
accruing hereunder from and after the date of such transfer, and it shall be
deemed and construed, without further agreement between the parties, that any
transferee has assumed and shall carry out all covenants and obligations
thereafter to be performed by Sublandlord hereunder. Sublandlord shall transfer
and

                                      -6-
<PAGE>

deliver any security of Subtenant to the transferee of the tenant's interest
under the Master Lease, and thereupon Sublandlord shall be discharged from any
further liability with respect thereto.

     10.  Relationship to Master Lease: This Sublease is subject and subordinate
          ----------------------------
to the Master Lease. Sublandlord shall perform all of its obligations under the
Master Lease to the extent Subtenant is not required to perform such obligations
under this Sublease. In the event, however, that Sublandlord defaults in the
performance of any of Sublandlord's remaining obligations under the Master
Lease, then Subtenant shall give Sublandlord written notice thereof specifying
in what manner Sublandlord has defaulted, and if such default is not cured by
Sublandlord within thirty (30) days thereafter (except that if such default
cannot be cured within said thirty (30) day period, then such period shall be
extended for an additional reasonable time, provided that Sublandlord commences
to cure such default within such thirty (30) day period and proceeds diligently
thereafter to effect such cure as quickly as reasonably possible), then
Subtenant shall be entitled to cure such default and promptly collect from
Sublandlord Subtenant's reasonable expenses in so doing. Subtenant shall not be
required, however, to wait the entire cure period described herein if earlier
action is required to comply with any applicable governmental law, regulation or
order. Sublandlord shall indemnify, defend, protect, and hold harmless Subtenant
from any and all liability, damages, claims, actions, demands and costs
(including reasonable and actual attorneys' fees), resulting, directly or
indirectly, from Sublandlord's failure to perform such remaining obligations of
Sublandlord under the Master Lease. Upon any termination of the Master Lease,
this Sublease shall also terminate except as otherwise provided in the Consent
of the Master Landlord; provided, however, that if the Master Lease is
terminated as a result of a default by Sublandlord of such remaining obligations
of Sublandlord under the Master Lease, Sublandlord shall be liable to Subtenant
for all damages resulting therefrom, and Subtenant shall have all rights and
remedies that would otherwise be available to it at law or in equity as a result
of such default. Provided that Subtenant is not then in default (after
applicable notice and cure periods) under this Sublease, Sublandlord shall not
enter into any amendment or modification of the Master Lease which will
materially and adversely affect Subtenant or Subtenant's use and occupancy of
the Premises without the consent of Subtenant, nor shall Sublandlord consent to
a termination of the Master Lease (except as specifically permitted by this
Sublease), or a surrender thereof without the consent of Subtenant, which
consent shall not be unreasonably withheld. Subtenant hereby expressly assumes
and agrees: (i) to comply with all provisions of the Master Lease which are
incorporated hereunder applicable to the Sublease Term; and (ii) to perform all
the obligations on the part of the "Tenant" to be performed under the terms of
the Master Lease during the term of this Sublease which are incorporated
hereunder. In the event of a conflict between the provisions of this Sublease
and the Master Lease, as between Sublandlord and Subtenant, the provisions of
this Sublease shall control. In the event of a conflict between the express
provisions of this Sublease and the provisions of the Master Lease, as
incorporated herein, the express provisions of the Sublease shall prevail.

     11.  Other Sublease Terms:
          ---------------------

              A.  Incorporation By Reference. Except as set forth below, the
                  --------------------------
terms and conditions of this Sublease shall include all of the terms of the
Master Lease identified in Section 11B (as modified) and such terms are
incorporated into this Sublease as if fully set forth herein, except that: (i)
each reference in such incorporated sections to "Lease" shall be deemed a
reference to "Sublease"; (ii) each reference to the "Premises" shall be deemed a
reference to the Premises leased by

                                      -7-
<PAGE>

Sublandlord to Subtenant; (iii) each reference to "Landlord" and "Tenant" shall
be deemed a reference to "Sublandlord" and "Subtenant", respectively, except as
otherwise expressly set forth herein; (iv) with respect to work, services,
repairs, restoration, insurance, indemnities, representations, warranties or the
performance of any other obligation of Master Landlord under the Master Lease,
the sole obligation of Sublandlord shall be to request the same in writing from
Master Landlord as and when requested to do so by Subtenant, and to use
Sublandlord's commercially reasonable efforts (without requiring Sublandlord to
spend more than a nominal sum) to obtain Master Landlord's performance; (v)
except as otherwise specifically provided in this Sublease, with respect to any
obligation of Subtenant to be performed under this Sublease, wherever the Master
Lease grants to Sublandlord a specified number of days to perform its
obligations under the Lease, except as otherwise provided herein, Subtenant
shall have three (3) fewer days to perform the corresponding obligation under
this Sublease, including, without limitation, curing any defaults; (vi) with
respect to any approval required to be obtained from the "Landlord" under the
Master Lease, such consent must be obtained from both Master Landlord and
Sublandlord, and the approval of Sublandlord may be withheld if Master
Landlord's consent is not obtained; (vii) in any case where the "Landlord"
reserves or is granted the right to manage, supervise, control, repair, alter,
regulate the use of, enter or use the Premises or any areas beneath, above or
adjacent thereto, such reservation or grant of right of entry shall be deemed to
be for the benefit of both Master Landlord and Sublandlord; (viii) in any case
where "Tenant" is to indemnify, release or waive claims against "Landlord", such
indemnity, release or waiver shall be deemed to run from Subtenant to both
Master Landlord and Sublandlord; (ix) in any case where "Tenant" is to execute
and deliver certain documents or notices to "Landlord", such obligation shall be
deemed to run from Subtenant to both Master Landlord and Sublandlord; (x) all
payments shall be made to Sublandlord; and (xi) Subtenant shall pay all consent
and review fees set forth in the Master Lease to both Master Landlord and
Sublandlord.

          B.  Master Lease Terms Incorporated Into Sublease: The following terms
              -----------------------------------------------
of the Master Lease are incorporated into this Sublease as provided in Section
11A hereof:

                  (1)  Paragraph 1 (Premises);

                  (2)  Paragraph 5 (Use); provided, however, that (i) the second
sentence of Paragraph 5D(ii) entitled "Existing Environmental Condition" is
deleted and shall not become part of the Sublease; and (ii) the reference in
incorporated Paragraph 5D(iii) to Exhibit F shall be to Exhibit F of this
                                  ---------
Sublease, which lists the Hazardous Materials necessary for Subtenant's
operations, and the permitted maximum quantities (where indicated).

                  (3)  Paragraph 6 (Assignment and Subletting); provided,
however, that (i) if any Sublet proposed to be entered into by Subtenant
requires the prior written consent of Master Landlord pursuant to the Master
Lease, Subtenant shall not enter into such Sublet transaction unless and until
Master Landlord's prior written consent shall have been obtained; (ii) Paragraph
6.B, clause (iii) permitting an assignment to Vantis Corporation shall be
deleted and not become a part of the Sublease; and (iv) the amount of "fifty
percent (50%) of any excess of the Subrent" referred to in the fourth sentence
of Paragraph 6F shall be changed to "sixty-seven percent (67%) of any excess of
the Subrent".

                                      -8-
<PAGE>

                  (4)  Paragraph 7 (Alterations); provided, however, that the
following phrase shall be deleted from the first two sentences of Paragraph 7.A
(Consent to Alterations): "Landlord shall approve or disapprove of the initial
Tenant Improvements to be constructed by Tenant in the Premises in accordance
with the procedure set forth in Exhibit C. Except as provided in Exhibit C,..."
                                ---------                        ---------

                  (5)  Paragraph 8 (Repair and Maintenance); provided, however,
that: (i) the incorporation of Paragraph 8 is subject to the limitation set
forth in Section 12 hereof that Sublandlord is not assuming or agreeing to
perform the obligations of the "Landlord" set forth in Paragraph 8 of the Master
Lease, and the extent of its obligation is to use commercially reasonable
efforts to cause the Master Landlord to perform the obligations of the Landlord
under the Master Lease; (ii) in Paragraph 8.B(ii) (Building and Outside Area
Expenses), all references to "Landlord" therein shall refer to Master Landlord,
and the reference to "Landlord's standard management fee" shall refer to the
management fee charged to Sublandlord by Master Landlord.

                  (6)  Paragraph 9 (Utilities and Services).

                  (7)  Paragraph 10 (Real Property Taxes); provided, however,
that Subtenant's obligation to pay "Tenant's Project Percentage" of all Real
Property Taxes shall commence on the Delivery Date of this Sublease.

                  (8)  Paragraph 11 (Insurance); provided, however, that the
last paragraph of Paragraph 11.B (Tenant's Insurance) relating to the right to
self insure is deleted and is not part of the Sublease.

                  (9)  Paragraph 12 (Project Costs); provided, however, that (i)
Subtenant's obligation to pay its share of Real Property Taxes, Project Property
Insurance, and Building and Outside Area Expenses shall commence on the Delivery
Date of this Sublease; and (ii) Paragraph 12.C (Audit Rights) shall not be
incorporated into the Sublease, but if so requested by Subtenant, Sublandlord
shall use reasonable efforts to exercise its rights under the Master Lease to
audit Master Landlord's records in accordance with the terms thereof for the
benefit of Subtenant so long as Subtenant pays all costs incurred by Sublandlord
in exercising such rights.

                  (10) Paragraph 14 (Notices); provided, however, that the
address for notices for Subtenant until the Delivery Date is 945 Stewart Drive,
Sunnyvale, California 94086, and the address for notices for Sublandlord is 5555
NE Moore Court, Hillsborough, Oregon, 97124, Attention: General Counsel.

                  (11) Paragraph 15 (Default); provided, however, that
notwithstanding clause (v) of Section 11.A of this Sublease: (i) the time period
set forth in incorporated provision Paragraph 15.A(i) is changed from five (5)
to three (3) days; (ii) the time period set forth in Paragraph 15.A(ii) of
thirty (30) days is changed to twenty-one (21) days; with respect to the
incorporated provision Paragraph 15.A(vii), the time period of twenty-four (24)
hours is changed to twelve (12) hours.

                  (12) Paragraph 16 (Surrender of the Premises); provided,
however, that the following phrase is deleted from the incorporated provision
Paragraph 16.B, first sentence: "... all

                                      -9-
<PAGE>

those Tenant Improvements which Tenant is required to remove pursuant to Exhibit
                                                                         -------
C, ...", and the term "Tenant Improvements" is deleted from such Paragraph 16.B
-
wherever it appears. If Subtenant Fails to surrender the Premises in the
condition required by this Sublease, Subtenant shall indemnify, protect, defend
and hold harmless Sublandlord and Sublandlord's agents against all liabilities
resulting from Subtenant's failure to perform such obligations, including,
without limitation, any liability that Sublandlord may have under Paragraph 16.C
(Indemnification of Landlord) which results from Subtenant's failure to perform
such obligations.

                  (13) Paragraph 17 (Attorneys' Fees).

                  (14) Paragraph 18 (Liens).

                  (15) Paragraph 19 (Subordination); provided, however, that (i)
Sublandlord shall not have an obligation to obtain a Subordination Agreement for
the benefit of Subtenant; and (ii) the following proviso is deleted from the
fourth sentence of incorporated Paragraph 19.A (Documentation): "... provided
and on the condition that the Holder agrees in writing in a separate agreement
not to disturb Tenant's quiet enjoyment of the Premises so long as Tenant is not
in default under this Lease beyond any applicable cure period."

                  (16) Paragraph 20 (Mortgagee Protection).

                  (17) Paragraph 21 (Condemnation); provided, however, that the
reference to "Landlord" in incorporated Paragraph 21.E (Sale Under Threat Of
Condemnation) shall be deemed to refer to Master Landlord.

                  (18) Paragraph 22 (Holding Over);

                  (19) Paragraph 23 (Entry by Landlord); provided, however, that
Master Landlord shall have all of the rights to enter that are described by
incorporated Paragraph 23.

                  (20) Paragraph 24 (Estoppel Certificate Information);
provided, however, that the time period of ten (10) days set forth in said
incorporated provision is changed to seven (7) days.

                  (21) [Intentionally omitted];

                  (22) Paragraph 26 (Landlord's Right to Perform Tenant's
Covenants); provided, however, that the time period of thirty (30) days set
forth in said incorporated Paragraph 26 shall be changed to twenty-one (21)
days.

                  (23) Paragraph 27 (Tenant's Remedy); provided, however, that
the phrase "look solely to the Project (and any insurance proceeds relating
thereto) for satisfaction of any liability of Landlord and" shall be deleted
from the fourth through sixth lines, and the phrase "look to other assets of
Landlord nor" shall be deleted from the sixth and seventh lines. In addition,
and notwithstanding anything in this Sublease or the Master Lease to the
contrary, Subtenant hereby releases Sublandlord and Sublandlord's agents,
contractors and representatives from, and Subtenant covenants that it shall not
under any circumstance seek to recover from Sublandlord or Sublandlord's

                                     -10-
<PAGE>

agents, contractors or representatives any incidental or consequential damages
suffered by Subtenant in connection with the Premises and/or this Sublease,
including, without limitation, any loss of use, loss of profits or revenues,
cost of capital, loss of goodwill, or claims of Subtenant's customers or
suppliers as a result of Sublandlord's failure to perform any obligation under
this Sublease or the Master Lease.

                  (24)  Paragraph 29 (Financial Covenants);

                  (25)  Paragraph 30 (Parking);

                  (26)  Paragraph 31 (Quiet Enjoyment);

                  (27)  Paragraph 32 (Modifications for Lender); provided,
however, that the reference in such incorporated provision to "Landlord's
lender" shall mean any lender of Master Landlord.

                  (28)  Paragraph 33 (Signs);

                  (29)  Paragraph 34 (Acceptance);

                  (30)  Paragraph 35 (Recording; Quitclaim);

                  (31)  Paragraph 36 (Brokers); provided, however, that the term
"Brokers" as used in such incorporated provision shall mean The Staubach Company
(the broker for Sublandlord), and C.B. Richard Ellis (the broker for Subtenant).

                  (32)  Paragraph 40 (General); provided, however, that (i) with
respect to the incorporation of Paragraph 40.J (Exhibits), the only exhibits
which are incorporated into the Sublease from the Master Lease are those
exhibits referred to elsewhere in this Sublease and Exhibits A (Diagram of 995
Building and 985 Building), B (Legal Description of Project), C-3 (Tenant
Improvement Building Standards), E (Project Rules and Regulations), and H
(Signage Program).

          C.  Notwithstanding the foregoing, but not in limitation of the
application of the foregoing, it is expressly agreed and understood that the
following provisions of the Master Lease are not incorporated into this
                                             ---
Sublease, and Subtenant shall have no right or benefits arising from any of the
following:

                  (i)   Paragraph 37 (Extension Option);

                  (ii)  Paragraph 38 (Right of First Offer);

                  (iii) Exhibit C (Work Letter Agreement), except Exhibit C-3,
which is incorporated into this Sublease.

    12. Maintenance Responsibilities of Sublandlord and Master Landlord: The
        ---------------------------------------------------------------
parties acknowledge that Paragraph 8 of the Master Lease obligates Master
Landlord to provide certain levels of maintenance, repair and replacement
("Master Landlord's Repair Obligations"), and Sublandlord and Subtenant agree as
follows with respect to this subject:

                                     -11-
<PAGE>

          A.  Sublandlord shall use commercially reasonable efforts to enforce
Master Landlord's Repair Obligations. Such enforcement shall include, without
limitation, upon Subtenant's written request, (i) promptly notifying Master
Landlord of its non-performance of Master Landlord's Repair Obligations and
requesting that Master Landlord perform such obligations, and/or (ii) assigning,
at Sublandlord's option in Sublandlord's sole and absolute discretion,
Sublandlord's rights under the Master Lease to Subtenant to the extent
reasonably necessary, in Sublandlord's judgment, to permit Subtenant to
institute legal proceedings against Master Landlord to obtain the performance of
Master Landlord's Repair Obligations; provided, however, that if Subtenant
commences a lawsuit or other action, Subtenant shall pay all costs and expenses
incurred in connection therewith, and Subtenant shall indemnify, defend (with
counsel reasonably acceptable to Sublandlord) protect and hold harmless
Sublandlord from and against all losses, costs, claims, liabilities and damages
(including attorneys' fees) in connection therewith.

          B.  Sublandlord shall have no maintenance or repair obligations with
respect to the Premises except for its obligation to use commercially reasonable
efforts to enforce Master Landlord's Repair Obligations.

    13. Damage and Related Termination Rights. The parties acknowledge that
        -------------------------------------
Paragraph 13 (Damage or Destruction) and Paragraph 11.D (Landlord's Insurance)
of the Master Lease governs the rights of Master Landlord and Sublandlord
concerning casualty insurance and damage to the Premises by fire or other peril,
and Sublandlord and Subtenant agree as follows with respect to this subject as
it relates to the Premises.

          A.  Sublandlord shall use reasonable efforts to enforce the
obligations of Master Landlord pursuant to Paragraph 8 and Paragraph 11.D.
Except to the extent of its obligations stated in the immediately preceding
sentence, Sublandlord shall not be obligated to obtain insurance or restore
damage to the Premises caused by fire or other peril, and shall not be liable
for any failure by Master Landlord to perform its obligations under the Master
Lease.

          B.  The parties acknowledge that Master Landlord has the right to
terminate the Master Lease in certain circumstances pursuant to Paragraph 13 in
the Master Lease. In the event Master Landlord exercises any such right of
termination, the Sublease shall terminate on the date the Master Lease
terminates.

          C.  The parties acknowledge that Sublandlord has the right to
terminate the Master Lease in certain circumstances pursuant to Paragraph 13.D
(Tenant's Right to Terminate). If Sublandlord becomes entitled to terminate the
Master Lease pursuant to said Paragraph 13.D, then it may do so in its sole
discretion, without the consent of Subtenant, and if it so elects to terminate
the Master Lease then the Sublease shall terminate on the date the Master Lease
terminates. Notwithstanding the foregoing sentence, provided that Subtenant is
not then in default (after applicable notice and cure periods) under this
Sublease, Sublandlord will not terminate the Master Lease pursuant to said
Paragraph 13.D without Subtenant's prior written consent (not to be unreasonably
withheld or delayed). If Sublandlord requests Subtenant's request to any such
termination and Sublandlord has not received Subtenant's written response to
such request within ten (10) days after Sublandlord's request therefor, then
Subtenant shall be deemed to have consented to Sublandlord's termination of the
Master Lease. If Subtenant disapproves any request of Sublandlord

                                     -12-
<PAGE>

for Subtenant's consent to Sublandlord's termination of the Master Lease
pursuant to said Paragraph 13.D, then Subtenant shall, concurrently with
Subtenant's disapproval of such request, deliver to Sublandlord Subtenant's
written agreement that the Sublease remains in full force and effect and that
Subtenant shall provide to Sublandlord such reasonable assurances as Sublandlord
may then require for Subtenant's continued performance of its obligations under
this Sublease.

          D.  Rents and other payments of Subtenant under the Sublease shall be
reduced or abated while repairs are being made necessitated by damage by fire or
other peril for the period of time and in proportion that the Premises are
unsuitable for Subtenant's business use, except as provided below. Under no
circumstance, however, shall the percentage to which Rent is abated under this
Sublease exceed the percentage to which Rent is abated under the Master Lease.
If such damage results from the act of Subtenant, its employees, agents,
contractors, or invitees, then (i) such damage shall be repaired by Subtenant
under the control, direction and supervision of Master Landlord (if Master
Landlord so elects), and (ii) Rent and other payments of Subtenant due under
this Sublease shall not be reduced or abated (except to the extent of insurance
proceeds actually received by Sublandlord as a result of such damage).

          E.  Notwithstanding anything to the contrary contained in this
Sublease, in no event shall Sublandlord or Master Landlord be obligated to
repair or replace Tenant's Personal Property or any Alterations existing at the
time of damage or destruction. If Subtenant desires to repair and/or replace
Subtenant's Personal Property and/or Alterations, the same shall be undertaken
and completed by Subtenant, at Subtenant's sole cost and expense, promptly
following the date of the damage or destruction.

     14.  Sublandlord's Representations: Sublandlord represents and warrants
          -----------------------------
that (i) the copy of the Master Lease attached hereto is a true, correct and
complete copy thereof; (ii) there exist no amendments, modifications or other
agreements (whether oral or written) affecting the Master Lease except as
attached thereto; (iii) neither Sublandlord nor Master Landlord is in default
under the provisions of the Master Lease nor is there any event, condition or
circumstance existing which with notice, the passage of time, or both, would
constitute a default thereunder; and (iv) the Master Lease is in full force and
effect.

     15.  Conditions Precedent: This Sublease and Sublandlord's and Subtenant's
          --------------------
obligations hereunder are conditioned upon the written consent of Master
Landlord. If Sublandlord fails to obtain Master Landlord's consent to this
Sublease within thirty (30) days after execution of this Sublease by
Sublandlord, then Sublandlord or Subtenant may terminate this Sublease by giving
the other party written notice thereof, and Sublandlord shall return to
Subtenant its payment of the first month's Rent paid by Subtenant pursuant to
Paragraph 4 hereof and the Security Deposit, and neither party shall have any
further rights or obligations under this Sublease.

     16.  Authority to Execute: Subtenant and Sublandlord each represent and
          --------------------
warrant to the other that each person executing this Sublease on behalf of each
party is duly authorized to execute and deliver this Sublease on behalf of that
party.

     17.  Approvals: Except as otherwise provided in this Sublease, whenever
          ---------
this Sublease requires an approval, consent, designation, determination,
selection or judgment by either

                                     -13-
<PAGE>

Sublandlord or Subtenant, such approval, consent, designation, determination,
selection or judgment and any conditions imposed thereby shall not be
unreasonably withheld or delayed. Sublandlord may, however, withhold its consent
or approval whenever the consent or approval of Master Landlord has not been
obtained.

     18.  Counterparts: This Sublease may be executed in counterparts, each of
          ------------
which shall be an original, but all of which taken together shall constitute one
and the same Sublease.

     IN WITNESS WHEREOF, the parties have executed this Sublease to be effective
as of the Effective Date.


SUBTENANT:                              SUBLANDLORD:

VITRIA TECHNOLOGY,                      LATTICE SEMICONDUCTOR CORPORATION,
a Delaware corporation                  a Delaware corporation


By: /s/ Karen Cottle                    By: /s/ Martin R. Baker
    --------------------                    ---------------------

Name: Karen Cottle                      Name: MARTIN R. BAKER
      ------------------                      -------------------

Its: General Counsel                    Its: VP & GENERAL COUNSEL
     -------------------                     --------------------


By: /s/ JoMei Chang                     By: _____________________
    --------------------

Name: JoMei Chang                       Name: ___________________
      ------------------

Its: CEO                                Its: ____________________
     -------------------

                                     -14-