MATTSON TECHNOLOGY TO PRESENT AT UPCOMING TECHNOLOGY CONFERENCES

FREMONT, Calif.- May 12, 2005 - Mattson Technology, Inc. (NASDAQ: MTSN), a leading supplier of advanced process equipment used to manufacture semiconductors, today announced that it will be presenting at JPMorgan's 33 rd Annual Technology Conference, Smith Barney Citigroup's Sixth Annual Semiconductor Conference and Bear Stearns' 16 th Annual Technology Conference. The JPMorgan conference will be held May 16 through May 19, 2005 at the Westin St. Francisco, San Francisco, CA. The Smith Barney Citigroup Conference will be held June 1 and June 2, 2005 at the Monterey Plaza Hotel, Monterey, CA. The Bear Stearns Conference will be held June 7 and June 8, 2005 at the Grand Hyatt New York, Park Avenue at Grand Central, New York City, NY.

Presentation and webcast times are as follows:

• David Dutton, chief executive officer, will be presenting at the JPMorgan conference on May 17 at 11:45 a.m. Pacific Time.
• Ludger Viefhues, chief financial officer, will be presenting at the Smith Barney Citigroup conference on June 1 at 2:50 p.m. Pacific Time.
• Ludger Viefhues will be presenting at the Bear Stearns conference on June 7 at 10:00 a.m. Eastern Time.

About Mattson Technology, Inc.

Mattson Technology, Inc. is the leading supplier of dry strip equipment and the second largest supplier of rapid thermal processing equipment in the global semiconductor industry. The company's strip and RTP equipment utilize innovative technology to deliver advanced processing performance and productivity gains to semiconductor manufacturers worldwide for the fabrication of current- and next-generation devices. For more information, please contact Mattson Technology, Inc., 47131 Bayside Parkway, Fremont, Calif. 94538. Telephone: (800) MATTSON/(510) 657-5900. Fax: (510) 492-5911. Internet: www.mattson.com.