MATTSON TECHNOLOGY WINS FOLLOW-ON STRIP AND RTP ORDERS FROM PROMOS

FREMONT, Calif. — September 12, 2005 — Mattson Technology, Inc. (NASDAQ: MTSN), a leading supplier of advanced process equipment used to manufacture semiconductors, today announced that it has received follow-on orders for its Aspen III ICPHT and Helios RTP systems from ProMOS Technologies (5387.TWO). The systems are scheduled to begin shipment in September and will be used in ProMOS’ 300 mm Fab 3 at Central Taiwan Science Park (CTSP) for the volume production of advanced memory devices, including 512 Mb and 1 Gb DDR2 DRAM stacked capacitors with 90 nm technology.

“We utilize the most advanced technology to expand our DRAM manufacturing capacity and ramp up production, allowing us to deliver high-quality products to the market quickly,” said Dr. Len Mei, senior vice president of ProMOS Technologies. “Mattson’s high-performance, low-cost-of-ownership strip and RTP systems, along with its excellent customer services in Taiwan, were key elements in our decision to continue to select the company as a business partner to supply our process technology requirements.”

“Memory chipmakers require advanced tools with processing capabilities to address the most challenging applications and increase productivity for manufacturing at the 90 nm node and beyond,” said Randy Y. Matsuda, Mattson Technology’s Global Business Operations vice president & general manager, Asia. “The excellent processing performance, reliability and high throughput of our Aspen III ICPHT strip and Helios RTP systems, as well as our dedicated support, continue to earn us a position as a vendor of choice at ProMOS.”

Featuring Mattson's proprietary inductively coupled plasma (ICP) source technology, the Aspen III ICPHT provides increased throughput, improved process performance and reliability for FEOL and BEOL strip applications.

The Helios addresses the most demanding RTP applications, including nickel silicide formation and ultra-shallow junction spike anneals, enabled by an advanced model-based temperature control for high productivity, excellent processing performance and superior cost-of-ownership.

About ProMOS

ProMOS Technologies, Hsin-Chu, Taiwan, is a full-blown memory solution provider and is renowned in the global DRAM industry for its outstanding performance in manufacturing excellence and technology advancement. The company manufactures high-performance and high-density commodity DRAM memory chips as well as pseudo-SRAM and lower power SDRAM products. ProMOS is listed on Taiwan GreTai Securities Market. For more information, please visit www.promos.com.tw.

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.