MATTSON TECHNOLOGY, STEAG AND CFM MERGER SET FOR CLOSING; MATTSON ANNOUNCES A NEW CFO, LUDGER VIEFHUES

FREMONT, Calif. - December 18, 2000 - Mattson Technology, Inc. (Nasdaq: MTSN), a leading supplier of advanced process equipment used to manufacture semiconductors, today announced that Mattson, STEAG and CFM Technologies have acknowledged satisfaction of key closing conditions and waived all independent rights to terminate their agreements. Completion of the mergers of Mattson Technology with CFM and STEAG's semiconductor equipment division now only requires certain previously agreed upon closing deliverables in order to take place, as planned, in early January.

"With these actions by the parties, this deal is locked on course for final closing, and Mattson Technology can now fully enjoy the benefits of the "Power of Three" merger announced on June 28 of this year. We look forward to a smooth conclusion of the merger and integration process," noted Brad Mattson, Mattson Technology's CEO. "Our customers will now begin to benefit from our multiproduct offerings and critical mass. They will now have a comprehensive choice from our strong 300mm-tool selection, and the customer support of a company solidly established in Asia, Europe and the United States. We become a provider of choice to meet the demands of the rapidly expanding Asian foundry market."

Mattson Technology, with the increased financial stability of a $500 million company, after the closing will be ranked among the top 15 semiconductor equipment manufacturers in the world. The company, already the leader in Dry Strip, will become the second largest manufacturer of Rapid Thermal Processing (RTP) systems in the world, and with CFM Technologies and STEAG's Wet Products Group working together, Mattson will become a leader in that market also.

In line with today's announcement, Mattson Technology also announced the appointment of Ludger H. Viefhues, 58, to the position of chief financial officer (CFO). Viefhues, a seasoned veteran, was previously CFO of STEAG RTP Systems GmbH. He will immediately take over responsibility for the strategic development and management of all Mattson Technology financial, investor relations, and merger and acquisition programs.

Mattson CEO Brad Mattson is very excited about Viefhues joining Mattson, stating "Mr. Viefhues brings to Mattson not only the experience of financial management of several multi-billion dollar companies, but also very important international experience having been the CFO of large global companies in both the U.S. and Germany." Prior to STEAG, Viefhues most recently held the position of CEO at MEMC (Monsanto Electronic Materials Co. in St. Louis, Mo.), a leader in the SEMI industry. Prior to being appointed CEO at MEMC, Viefhues was the company's CFO. Before MEMC, Viefhues held the post of CFO at Huels AG (Germany), a highly respected German company with sales in excess of $10B. He earned his MBA in finance from University of Muenster (Germany).

Viefhues succeeds Brian McDonald, who has left the company to take a position outside of the capital equipment industry. Viefhues will begin his responsibilities at Mattson Technology immediately.

This Press Release contains forward looking statements regarding, among other matters, the Company's future financial performance and the completion of the Steag and CFM acquisitions. Forward looking statements address matters which are subject to a number of risks and uncertainties. In addition to the general risks associated with the development of complex technology, future results of the Company will depend on a variety of factors, including the timing of significant orders, the ability of the Company to bring new systems to market, the timing of new product releases by the Company's competitors, slowdowns in the semiconductor industry, other competitive factors, satisfaction of conditions to pending acquisition and risks of integration. Reference is made to the Company's filings with the Securities and Exchange Commission for further discussion of risks and uncertainties regarding the Company's business.

About Mattson Technology

Mattson Technology Inc., is a leading supplier of thermal, plasma and wet semiconductor processing equipment. The company's products combine advanced process technology on a high productivity platform, backed by industry-leading support. Since beginning operations in 1989, the company's core vision has been to help bring technology leadership and productivity gains to semiconductor manufacturers worldwide. Headquartered in Fremont, Calif., the company maintains sales and support centers throughout the United States, Europe, Asia/Pacific and Japan. For more information, please contact Mattson Technology Inc., 2800 Bayview Drive, Fremont, Calif. 94538. Telephone: (800) MATTSON. Fax: (510) 657-0165. Internet:www.mattson.com