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                                                                   EXHIBIT 10.17
 
                              SEVERANCE AGREEMENT
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          This Severance Agreement is entered into as of this 30th day of
December, 1996 by and between Aseco Corporation, a Delaware corporation (the
"Company"), and Dennis A. Legal (the "Employee").

                                   Recitals:
                                   -------- 

          WHEREAS, the Employee is an executive officer of the Company; and

          WHEREAS, the Company and the Employee wish to provide for the payment
of certain severance compensation by the Company to the Employee in the event
the Employee's employment by the Company is terminated.

          NOW, THEREFORE,  in consideration of the Employee's continued service
to the Company and other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties agree as follows:

          1.  Definitions.
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          "Benefit Period" shall mean the six (6)-month period following the
Termination Date.

          "Cause" shall be deemed to exist if the Board of Directors of the
Company or its successor in good faith determines, after giving the Employee
notice and an opportunity to be heard, that the Employee has committed an act
constituting fraud, embezzlement, larceny or theft.

          "Change in Control" shall mean (i) the sale, lease, transfer or other
disposition by the Company of all or substantially all of its assets in a single
transaction or a series of related transactions; (ii) the merger or
consolidation of the Company with another entity in which the stockholders of
the Company immediately prior to such merger or consolidation hold less than 50%
of the outstanding voting stock of the surviving or resulting corporation
immediately following such transaction; or (iii) the sale or exchange (to or
with any person or entity other than the Company) by the stockholders of the
Company of more than 50% of the outstanding voting stock of the Company in a
single transaction or series of related transactions.


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          "Ineligibility Period" shall mean that portion of the Benefit Period
when the Employee is ineligible for coverage under the Company's group life or
group health insurance policies.

          "Termination Date" shall mean the effective date of the termination of
the Employee's employment with the Company.

          2.  Severance.
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          In the event the Employee's employment by the Company is terminated
without Cause by the Company or any successor within twelve (12) months
following a Change in Control, the Company or such successor shall (i) pay the
Employee within five days after the Termination Date a lump sum amount equal to
six (6) times the Employee's monthly base salary in effect at the time of such
termination (less applicable withholding taxes and FICA) and (ii) continue to
provide during the Benefit Period life and health insurance coverage to the
Employee, with benefits substantially comparable to those provided to executive
officers of the Company generally immediately prior to such termination.
Notwithstanding the foregoing, the Company shall have the right, in lieu of
providing such coverage during any Ineligibility Period, to pay the Employee an
amount equal to 200% of the amount it would have cost the Company to provide
such coverage during any Ineligibility Period, assuming the Employee were
eligible for coverage under the Company's group insurance policies and assuming
further no increase in premium costs under such policies after the commencement
of the Ineligibility Period.
 
          3.   Miscellaneous.
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               3.1   This Agreement constitutes the entire agreement between the
parties and supersedes all prior agreements and understandings, whether written
or oral, relating to the subject matter of this Agreement.

               3.2   This Agreement may be amended or modified only by a written
instrument executed by both the Company and the Employee.

               3.3   This Agreement shall be construed, interpreted and enforced
in accordance with the laws of The Commonwealth of Massachusetts.

               3.4   This Agreement shall be binding upon and inure to the
benefit of both parties and their respective successors and assigns, including
any corporation with which or into which the 

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Company may be merged or which may succeed to its assets or business.

               3.5   The captions of the sections of this Agreement are for
convenience of reference only and in no way define, limit or affect the scope or
substance of any section of this Agreement.

               3.6   In case any provision of this Agreement shall be invalid,
illegal or otherwise unenforceable, the validity, legality and enforceability of
the remaining provisions shall in no way be affected or impaired thereby.

          IN WITNESS WHEREOF, the parties hereto have executed this Agreement as
of the day and year set forth above.

                                          ASECO CORPORATION            
                                                                       
                                                                       
                                                                       
                                          By:___________________________
                                                                       
                                          Title:________________________
                                                                       
                                                                       
                                                                       
                                          EMPLOYEE                     
                                                                       
                                                                       
                                                                       
                                          ______________________________
                                          Dennis A. Legal               

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