<PAGE>
Exhibit 23.1
CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS
As independent public accountants, we hereby consent to the use of our
report included in this registration statement and to the incorporation by
reference in this registration statement of our report dated January 21, 2000
included in Mattson Technology Inc.'s Annual Report on Form 10-K for the year
ended December 31, 1999 and to all references to our Firm included in this
registration statement.
Arthur Andersen LLP
San Jose, California
September 21, 2000
