MENLO PARK, CA, July 12, 2005 — Ultra Clean Holdings, Inc. (Nasdaq: UCTT), a developer and supplier of critical subsystems for the semiconductor capital equipment industry, today announced the limited release of the Predator(TM) Integrated Gas-delivery System (IGS) substrate. The system combines the small size and weight of typical IGS substrates with the lower-cost and design-flexibility of traditional gas delivery systems. Currently, Predator is available in limited numbers, however the company plans full-scale production beginning in the second quarter of 2006.

Predator IGS
Predator technology was developed by UCT over the last several years, and comes to the market with a number of patents pending. Predator features standard fittings that constitute the gas flow path, along with precision supports that allow mating of industry standard top-mount gas-flow components. Predator fittings allow for the straightforward design of complex fluid flow paths, with the ability to mix-and-match standard lines with 1/8" or 3/8" lines, plus top and bottom manifolding. By reducing part and seal counts, Predator technology is designed to save time and money in field support.

Predator hardware meets or exceeds all applicable industry (SEMI) standards for gas delivery systems. These standards include specific requirements regarding vacuum leak integrity, temperature cycling, particle contribution, shock and vibration resistance and pressure drop.

Clarence Granger, UCT's President and CEO stated, "We're very pleased to be able to provide the new Predator substrate to our OEM customers and their end-users. Now the semiconductor capital equipment industry has an IGS substrate technology that is not based on machined blocks. This new approach delivers greater design flexibility and reduces cost and weight."

About Ultra Clean Holdings, Inc.
Ultra Clean Holdings, Inc. the parent company of Ultra Clean Technology Systems, 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 with additional locations in Austin, Texas; Portland, Oregon and Shanghai, China. Additional information is available at www.uct.com.

Safe Harbor Statement
This press release contains, or may be deemed to contain, "forward-looking statements" (as defined in the U.S. Private Securities Litigation Reform Act of 1995) which reflect Ultra Clean Holdings, Inc.'s current views with respect to future events and financial performance. Ultra Clean Holdings, Inc. uses words such as "anticipates," "believes," "plans," "expects," "future," "intends," "may," "will," "should," "estimates," "predicts," "potential," "continue" and similar expressions to identify these forward-looking statements. All forward-looking statements address matters that involve risks and uncertainties. Accordingly, you should not rely on forward-looking statements, as there are or will be important factors that could cause our actual results, as well as those of the markets we serve, levels of activity, performance, achievements and prospects to differ materially from the results predicted or implied by these forward-looking statements. These risks, uncertainties and other factors include, among others, those identified in "Risk Factors", "Management's Discussion and Analysis of Financial Condition and Results of Operations" and elsewhere in the Annual Report on Form 10-K filed with the Securities and Exchange Commission on March 30, 2005.