MATTSON TECHNOLOGY APPOINTS BRIAN MCDONALD CFO

FREMONT, Calif. — April 21, 1999 — Mattson Technology, Inc. (Nasdaq: MTSN), a leading supplier of advanced process equipment used to manufacture semiconductors, today appointed Brian R. McDonald to the position of Chief Financial Officer effective immediately. He will be replacing Rich Mora who will be leaving the Company to pursue personal interests. Mr. McDonald’s responsibilities as CFO at Mattson include both the strategic and tactical management of all finance, investor relations, and merger and acquisition activities.

Mr. McDonald joins Mattson Technology from National Semiconductor Corporation, where he most recently served as Vice President of Finance for the company’s Central Technology and Manufacturing division. In this role, Mr. McDonald managed the worldwide finance activities associated with a $2.5B manufacturing organization. He also previously had significant finance roles at National Semiconductor, Read-Rite Corporation, and Micro Linear Corporation.

Brad Mattson, CEO of Mattson Technology, commented, "We are, of course, disappointed to see Rich go. He's done a great job for Mattson and we wish him well in whatever he does. We also appreciate his assistance in finding a candidate of Brian's caliber. Brian's track record in finance and corporate accounting, investor relations, and M&A activities will be invaluable to Mattson." Mr. Mattson concluded, "Most importantly, Brian brings the perspective and experience of working with a ‘multi-billion dollar operation’. This is the kind of experience that can support Mattson’s goals in this next upturn. Brian is the right guy at the right time!"

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