MENLO PARK, CA, January 14, 2004 — Ultra Clean Holdings, Inc., the parent company of Ultra Clean Technology Systems and Service, Inc., announced today that it has filed a registration statement with the Securities and Exchange Commission (SEC) for the proposed initial public offering of its common stock. Credit Suisse First Boston will be the sole book-running manager for the proposed offering with J.P. Morgan Securities Inc. acting as joint-lead manager. Banc of America Securities LLC and Piper Jaffray & Co. will be co-managers.

Ultra Clean Holdings, Inc., designs, engineers and manufactures subsystems for the semiconductor capital equipment industry, focusing on gas delivery systems.

A registration statement relating to these securities has been filed with the Securities and Exchange Commission but has not yet become effective. These securities may not be sold nor may offers to buy be accepted prior to the time the registration statement becomes effective. This press release shall not constitute an offer to sell or the solicitation of an offer to buy nor shall there be any sale of these securities in any state in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state.

Copies of the preliminary prospectus, when available, can be obtained from the Prospectus Department of Credit Suisse First Boston LLC at One Madison Avenue, New York, New York 10010 (telephone no. 212-325-2580).