05.17.04

Sue Billat Joins Ultra Clean Board of Directors

MENLO PARK, CA, May 17, 2004 — Ultra Clean Holdings (NASDAQ: UCTT) the parent company of Ultra Clean Technology Systems and Service, Inc. today announced that Sue Billat, principal of Benchmark Strategies, has joined the company's board of directors, effective March 2004.

"Sue brings an incredible wealth of semiconductor equipment industry knowledge to our board, having served as both an industry executive and an independent analyst," said Clarence Granger, UCT’s president and chief executive officer. "We are very honored to have her join us."

Billat is principal and founder of Benchmark Strategies. She was a senior research analyst and managing director for semiconductor equipment and foundries at Robertson Stephens, where she worked from 1996 to 2002. Prior to joining Robertson, she was senior vice president of marketing for Ultratech Stepper. She serves on the board of directors of PDF Solutions. Billat holds bachelors and masters degrees in physics from Georgia Tech.

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.