MTSN Mattson Technology, Inc.

Mattson Technology, Inc. (NASDAQ: MTSN) today announced that it has priced its previously announced underwritten public offering of 6,800,000 shares of its common stock at a price to the public of $1.80 per share. The offering is expected to close on or about Monday, May 16, 2011, subject to satisfaction of customary closing conditions. Mattson Technology granted the underwriters a 30-day option to purchase at the public offering price up to an additional 1,020,000 shares of its common stock to cover over-allotments, if any. After deducting the underwriting discount but before deducting estimated offering expenses payable by the Company, the Company expects to receive net proceeds of approximately $11,492,000, assuming no exercise of the over-allotment option.

Needham & Company, LLC is acting as sole book running manager and Rodman & Renshaw, LLC and Roth Capital Partners are acting as co-managers for the offering.

Mattson Technology intends to use the net proceeds from this offering for general corporate purposes, which may include working capital, capital expenditures, other corporate expenses, and acquisitions of complementary products, technologies or businesses.

A shelf registration statement relating to the shares of common stock was previously filed with the Securities and Exchange Commission (the "SEC") and declared effective on September 30, 2010. A preliminary prospectus supplement relating to the offering has been filed with the SEC and a prospectus supplement relating to the offering will be filed with the SEC and will be available on the SEC's website at http://www.sec.gov. Copies of the prospectus supplement and accompanying prospectus, when available, may be obtained from Needham & Company, LLC, 445 Park Avenue, New York, NY 10022, (800) 903-3268.

This press release shall not constitute an offer to sell or the solicitation of an offer to buy these securities, nor shall there be any sale of these securities in any state or other jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or other jurisdiction.

"Safe Harbor" Statement Under the Private Securities Litigation Reform Act of 1995:

This press release contains forward-looking statements within the meaning of the federal securities laws. These statements involve risks and uncertainties that could cause actual results to differ materially, including, but not limited to, the satisfaction of customary closing conditions and whether or not Mattson Technology will consummate the offering, prevailing market conditions, the anticipated use of the proceeds of the offering which could change as a result of market conditions or for other reasons, and the impact of general economic, industry or political conditions in the United States or internationally. There can be no assurance that Mattson Technology will be able to complete the offering on the anticipated terms, or at all. Additional risks and uncertainties relating to the offering, Mattson Technology and its business can be found under the heading "Risk Factors" in Mattson Technology's Quarterly Report on Form 10-Q for the quarter ended April 3, 2011, in the preliminary prospectus supplement relating to the offering and in the prospectus supplement relating to the offering to be filed with the Securities and Exchange Commission. Mattson Technology assumes no duty or obligation to update or revise any forward-looking statements for any reason.

About Mattson Technology, Inc. Mattson Technology, Inc. designs, manufactures and markets semiconductor wafer processing equipment used in the fabrication of integrated circuits. We are a leading supplier of plasma and rapid thermal processing equipment to the global semiconductor industry, and operate in three primary product sectors: dry strip, rapid thermal processing and etch. Through manufacturing and design innovation, we have produced technologically advanced systems that provide productive and cost-effective solutions for customers fabricating current- and next-generation semiconductor devices.

Mattson Technology Contact Andy Moring Chief Financial Officer Mattson Technology, Inc. tel 510-657-5900 fax 510-492-5963 andy.moring@mattson.com Investor & Media Contact Laura Guerrant-Oiye, Principal Guerrant Associates tel 808-882-1467 lguerrant@guerrantir.com