PROMOS TECHNOLOGIES SELECTS MATTSON SYSTEMS FOR NEW 300 MM DRAM FAB IN TAIWAN

FREMONT, Calif.- November 29, 2005 - Mattson Technology, Inc. (NASDAQ: MTSN), a leading supplier of advanced process equipment used to manufacture semiconductors, today announced that ProMOS Technologies (5387.TWO) has placed follow-on orders for multiple RTP and strip systems for its new 300 mm fab in Taichung, Taiwan. The systems, which include the Helios, Aspen III ICPHT and Aspen III Strip for contact clean applications, will continue to be utilized by ProMOS for the volume production of 512 Mb DDR1/2 advanced memory devices using 90 nm technology. Delivery of these tools is expected to begin next month to support further 300 mm capacity expansion and expands the number of existing Mattson tools already installed at ProMOS' production facilities.

“At our new Fab 3, we are planning to have a wafer output of slightly under 10,000 300 mm wafers on 90 nm process in the fourth quarter of this year, so we need equipment that delivers increased throughput, greater processing flexibility and lower total cost-of-ownership to help us meet our aggressive 90 nm mass production schedule,” said Dr. Len Mei, senior vice president of ProMOS Technologies. “Mattson's strip and RTP systems are consistently outperforming competitive tools and meeting our high productivity and next-generation production requirements. We will continue to look to Mattson for its advanced technologies and strong local customer support.”

“For a DRAM leader such as ProMOS, advanced technology and maximum productivity are requirements for success,” said Randy Y. Matsuda, Mattson Technology's Global Business Operations vice president & general manager, Asia. “The proven performance of the Aspen III ICPHT, which recently won an extensive head-to-head evaluation against a competitive supplier, Aspen III Strip and Helios for processing next-generation 512 Mb and 1 Gb DRAM device designs resulted in these latest follow-on, multi-system orders. We look forward to continuing to support our long-standing customer with high-performance, low cost-of-ownership solutions that enable ProMOS to ramp production at its new 300 mm fab.”

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 Aspen III Strip system achieves excellent results for high-dose implant strip, photoresist and residue removal and surface cleaning for advanced applications, including low-k and oxygen and non-oxygen-based processes.

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.