05.04.05

ULTRA CLEAN TO PRESENT AT PIPER JAFFRAY TECHNOLOGY CONFERENCE

MENLO PARK, CA, May 4, 2005 / PRNewswire — Ultra Clean Holdings, Inc. (Nasdaq:  UCTT), the parent company of Ultra Clean Technology Systems and Service, Inc., announced that Clarence Granger, President and Chief Executive Officer, and Kevin Griffin, Acting Chief Financial Officer, will address the Piper Jaffray Seventh Annual Technology Conference. The conference will be held at the New York Palace Hotel, 455 Madison Avenue, New York, NY on Wednesday, May 11, 2005 at 10:50 am Eastern Time.

A link to the webcast will be available on the Investor Relations section of the Company’s website at www.uct.com during the live presentation. A replay of the webcast will be available approximately one hour after the live presentation.

About Ultra Clean Holdings, Inc.
Ultra Clean Holdings, Inc. is a developer and supplier of critical subsystems for the semiconductor capital equipment industry, focusing on gas delivery systems.  Ultra Clean offers its customers a complete outsourced solution for gas delivery systems, improved design-to-delivery cycle times, component neutral design and manufacturing and component testing capabilities.  Ultra Clean’s customers are primarily original equipment manufacturers of semiconductor capital equipment.  The Company is headquartered in Menlo Park, California.  Additional information is available at www.uct.com.