FREMONT, CA. April 8 , 2002 - Mattson Technology, Inc. (Nasdaq: MTSN), a leading supplier of advanced process equipment used to manufacture semiconductors, today announced that it has entered into definitive purchase agreements for the sale of 7.4 million shares of newly issued Common Stock. The investors in these transactions are the State of Wisconsin Investment Board, STEAG Electronic Systems AG (SES), Mattson's largest shareholder, and a new institutional investor.

The purchase price is $6.15 per share, resulting in an aggregate transaction value of $ 45.6 million. The transactions include 5.1 million shares to be sold to the State of Wisconsin Investment Board and 1.3 million shares to be sold to SES in exchange for the cancellation of $8.1 million of existing indebtedness. The Company intends to use net proceeds from this private placement for general corporate purposes. Bear, Stearns & Co. Inc. served as the sole placement agent for these transactions.

Mattson's Chief Executive Officer David Dutton commented "We have accomplished several objectives with this transaction, first in attracting a long-term oriented investor such as the State of Wisconsin Investment Board. Additionally, SES remains highly committed to our success, as evidenced by its participation in these transactions. We intend to continue strengthening our position as a leading supplier of semiconductor wafer processing equipment used in 'front-end' fabrication of integrated circuits. The proceeds from the transactions increase our substantial existing cash position and improve our financial flexibility to continue investing in our technology and global infrastructure while capitalizing on future growth opportunities."

The shares of Common Stock have not been registered under the Securities Act of 1933, as amended, and may not be offered or sold in the United States absent registration, or an applicable exemption from registration. The Company has agreed to register these shares for resale by the investors, and the transaction is subject to customary closing conditions, including conditions relating to the registration of the shares. The Company expects to close the transaction in its second fiscal quarter. This press release does not constitute an offer of any securities for sale.

This press release contains forward looking statements regarding, among other matters, the Company's future prospects and near-term outlook. Forward looking statements address matters that are subject to a number of risks and uncertainties that can cause actual results to differ materially. In addition to the general risks associated with the slowdown in the semiconductor industry and development of complex technology, our future results will depend on a variety of factors, including the timing of significant orders, our ability to timely manufacture and deliver ordered products, our ability to bring new systems to market, the timing of new product releases by our competitors, other competitive factors, and risks of integration following the STEAG-CFM acquisitions. 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. The Company assumes no obligation to update the information in this press release.

About Mattson Technology, Inc.

Mattson Technology, Inc. is a leading supplier of semiconductor wafer processing equipment used in "front-end" fabrication of integrated circuits. The company is a market leader in dry strip and RTP equipment, and its products combine advanced process technology on high-productivity platforms 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 and Asia. 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.