EXHIBIT 31.2

                                  CERTIFICATION

                            MATTSON TECHNOLOGY, INC.
                 SARBANES-OXLEY ACT SECTION 302(a) CERTIFICATION

I, Ludger Viefhues, certify that:

      1. I  have  reviewed  this  quarterly  report  on  Form  10-Q  of  Mattson
      Technology, Inc.;

      2.  Based on my  knowledge,  this  report  does  not  contain  any  untrue
      statement of a material fact or omit to state a material fact necessary to
      make the statements made, in light of the  circumstances  under which such
      statements were made, not misleading with respect to the period covered by
      this report;

      3. Based on my knowledge,  the financial  statements,  and other financial
      information  included  in this  report,  fairly  present  in all  material
      respects the financial condition,  results of operations and cash flows of
      the registrant as of, and for, the periods presented in this report;

      4. The registrant's other certifying  officer(s) and I are responsible for
      establishing  and  maintaining  disclosure  controls  and  procedures  (as
      defined in Exchange Act Rules  13a-15(e) and 15d-15(e)) for the registrant
      and have:

          (a) Designed such disclosure  controls and procedures,  or caused such
          disclosure   controls  and   procedures  to  be  designed   under  our
          supervision,  to ensure  that  material  information  relating  to the
          registrant,  including its consolidated subsidiaries, is made known to
          us by others within those entities,  particularly during the period in
          which this report is being prepared;

          (b)  Evaluated  the  effectiveness  of  the  registrant's   disclosure
          controls and procedures  and presented in this report our  conclusions
          about the effectiveness of the disclosure controls and procedures,  as
          of the  end of the  period  covered  by  this  report  based  on  such
          evaluation; and

          (c) Disclosed in this report any change in the  registrant's  internal
          control over financial reporting that occurred during the registrant's
          most recent fiscal quarter (the registrant's  fourth fiscal quarter in
          the case of an annual  report)  that has  materially  affected,  or is
          reasonably  likely to materially  affect,  the  registrant's  internal
          control over financial reporting; and

      5. The  registrant's  other  certifying  officer(s) and I have  disclosed,
      based on our most recent  evaluation  of internal  control over  financial
      reporting,  to the  registrant's  auditors and the audit  committee of the
      registrant's  board of directors  (or persons  performing  the  equivalent
      functions):

          (a) All significant deficiencies and material weaknesses in the design
          or operation of internal  control over financial  reporting  which are
          reasonably  likely to  adversely  affect the  registrant's  ability to
          record, process, summarize and report financial information; and

          (b) Any fraud,  whether or not material,  that involves  management or
          other  employees  who  have a  significant  role  in the  registrant's
          internal control over financial reporting.

Dated: November 5, 2004

              By:                        /s/ LUDGER VIEFHUES
                  --------------------------------------------------------------
                                           Ludger Viefhues
                  Executive Vice President - Finance and Chief Financial Officer