EXHIBIT 10.31

                                 AMENDMENT NO. 1

                    CHANGE OF CONTROL AND SEVERANCE AGREEMENT

     Amendment (hereinafter "Amendment") dated as of June 27, 2000 to a certain
Change of Control and Serverance Agreement (the "Agreement") dated April 10,
2000, by and between CFM Technologies, Inc., a Pennsylvania Business Corporation
having a place of business at 150 Oaklands Blvd., Exton, PA 19341 and Roger A.
Carolin, an individual residing at 158 Kentsdale Court, Malvern, PA 19355
("Carolin").

                                   WITNESSETH:

     WHEREAS, based upon a continuing desire to motivate Carolin's continued
employment, and in recognition of Carolin's continuing contribution to the
Company;

     NOW, THEREFORE, in consideration of the foregoing and the mutual promises
and covenants contained in the Agreement and herein, and intending to be legally
bound hereby, it is agreed to:

     1.   Delete Section 2 of the Agreement, in its entirety, and replace it
          with the following:

          "2. TERM

          This agreement shall terminate upon the first to occur of (i) five (5)
          years from execution hereof or (ii) two (2) years from the occurrence
          of an Event or upon the mutual agreement, in writing, of CFM and
          Carolin."

     2.   Delete Section 4(c) of the Agreement, in its entirety, and replace it
          with the following:

          "(c) TERMINATION BY CAROLIN FOR GOOD REASON. Any of the following
          actions or omissions by CFM or Successors and Assigns shall constitute
          good reason:

               (i)  Material breach by Successors and Assigns of any provision
                    of this Agreement which is not cured by Successors and
                    Assigns within fifteen (15) days of written notice thereof
                    from Carolin; or

               (ii) Any action by Successors and Assigns to intentionally harm
                    Carolin; or

              (iii) If, (i) upon the occurrence of an Event, Carolin's status,
                    title, position, and responsibilities are not expanded to
                    include responsibility for substantially all related
                    functional activities in the merger or combined
                    post-transition entity for which Carolin was responsible
                    immediately prior to the Event, or (ii) at any time
                    thereafter, a change occurs in Carolin's status, title,






                    position, work location or compensation which, in either
                    event, in Carolin's reasonable judgment, represents a
                    material adverse change from his status, title, position,
                    work location, compensation, or responsibilities existing or
                    in effect prior to such change, Carolin may, at his sole
                    option by providing written notice, at any time during the
                    term of this Agreement, deem such change to be good reason
                    under this Section 4(c). It is specifically agreed that
                    service as President-Wet Processing Division, Mattson
                    Technology, Inc. shall constitute a material adverse change
                    from Carolin's present status, title, position and
                    responsibilities and that Carolin's performance in such
                    capacity shall not be deemed a waiver of this sentence.

               (iv) The failure of CFM to have obtained an agreement,
                    satisfactory to Carolin, from any Successors and Assigns to
                    assume and agree to perform this Agreement prior to the
                    occurrence of an Event.

               (v)  The election by Carolin to terminate his employment at any
                    time after May 1, 2001 and prior to the expiration of this
                    Agreement. Such election under this sub-section shall be
                    valid only in the event that Carolin shall have undertaken a
                    documented, good faith effort to locate another person to
                    assume his responsibilities.

     Carolin's right to terminate his employment pursuant to this Section 4(c)
shall not be affected by his incapacity due to disability.

     In the event of any action or omission constituting good reason (a "Good
Reason Event") (1) if Carolin has terminated after May 1, 2001 and prior to
expiration of this Agreement, and has undertaken a documented good faith effort
to locate another person to assume his responsibilities, any options to purchase
common stock of CFM or Successors and Assigns held by Carolin immediately prior
to the occurrence of an Event shall vest immediately as of the date of such
termination, (2) Successors and Assigns will pay to Carolin his target annual
bonus for the current fiscal year on a pro rata basis corresponding to the date
of termination, (3) Carolin shall, in any case, agree to serve as a consultant
to Successors and Assigns for up to twenty-six (26) days during the six (6)
months following termination hereunder at times and locations and with duties as
Carolin and Successors and Assigns may mutually agree, and (4) Successors and
Assigns will pay Carolin twenty-four (24) monthly payments equal to one twelfth
of Carolin's then current annual base salary plus annual target bonus and the
amount of $3,500 for each day of consulting in excess of twenty-six (26) days."




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        IN WITNESS WHEREOF, the parties hereto, intending to be legally bound
hereby, have executed this Agreement as of the day and year first above written.



ROGER A. CAROLIN


By: /s/ ROGER A. CAROLIN                       Date: June 27, 2000
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CFM TECHNOLOGIES, INC


By: /s/ LORIN J. RANDALL, Secretary            Date: June 27, 2000
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