MENLO PARK, CA, July 12, 2004 — Ultra Clean Technology has announced that Dr. Mohamed Saleem will present a paper entitled “In Situ Mass Flow Verification for Semiconductor Processing” in the STS:ISM Contamination Free Manufacturing technical symposium of SEMICON West 2004 (San Francisco, CA July 12-14, 2004). Dr. Saleem will speak on Monday, July 12, as part of the morning program, scheduled for 9:00am to 12:00pm. Session 102-CFM, as well as Session 105-CFM will be co-chaired by Dr. Sowmya Krishnan, UCT’s Vice President of Technology and Chief Technology Officer. This participation is part of UCT’s active and on-going role in industry technology symposia. The sessions will be conducted at the San Francisco Marriott Hotel.

About Mass Flow Verification
In the nanometer-era of semiconductor manufacturing, decreasing device geometries require stringent control of the delivery of gases to the process tools. Controlling gas delivery, in turn, requires accurate flow control devices such as mass-flow controllers (MFCs). Compact mass flow verification (MFV) components have been developed to allow for the calibration of MFCs in situ the gas delivery subsystem, providing the accuracy of external MFV tools without needing to remove MFCs from the process tool. UCT has developed methods to evaluate MFV performance against industry standard test equipment. This has improved performance requirements designed to meet demanding industry standards and customer requirements.

About STS:ISM
The SEMI Technology Symposium (STS) on Innovations in Semiconductor Manufacturing (ISM) features papers that address practical solutions to current problems. Individual sessions will focus on a variety of subjects: strained-silicon technology, advanced wafer processing, interconnect technology, planarization processes, in situ metrology, contamination free manufacturing, MEMS technology and EHS issues. Registration for the symposium is through SEMI (www.semi.org).

About Dr. Sowmya Krishnan
Sowmya Krishnan, PhD, is Vice President of Technology and Chief Technology Officer at Ultra Clean Technology. In this position she oversees the technology and product development areas for semiconductor gas- and liquid-delivery systems. She has chaired the Standards Task forces at SEMI, and has chaired sessions on contamination-free manufacturing and gas delivery at SEMICON West, SEMICON Southwest, and CleanRooms West. Dr. Krishnan has authored several technical papers and editorials in the fields of microcontamination and semiconductor processing. She received MS and PhD degrees in chemical engineering from Clarkson University in Potsdam, NY. (Dr. Krishnan can be reached at 650/323-4100 or skrishnan@uct.com.).

About Dr. Mohamed Saleem
Mohamed Saleem, PhD, is Manager, Technology and Product Development at Ultra Clean Technology. An active participant in SEMI standards task forces for gas-panels, corrosion, surface-analysis, and stainless-steel, Dr. Saleem has published several papers in the field of materials science and has presented many papers at major industry conferences. He received his MS in chemical engineering from Tufts University in Medford, MA, and a PhD in materials science and engineering from the University of Florida in Gainsville. (Dr. Saleem can be reached at 650/323-4100 or msaleem@uct.com.)

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.