MKS Instruments Acquires Ion Systems and Umetrics


Wilmington, Mass., January 3, 2006 -- MKS Instruments, Inc. (NASDAQ: MKSI) announced that today it closed on transactions to acquire Ion Systems, Inc., a leading provider of electrostatic management solutions to semiconductor, flat panel display, data storage and other high technology manufacturers, and Umetrics AB, a leader in multivariate data analysis and modeling software for semiconductor, pharmaceutical, petrochemical and other manufacturing processes. The acquisitions are effective as of today.

Leo Berlinghieri, MKS' Chief Executive Officer and President, said, "These acquisitions support our strategy to improve process performance and productivity. With these technologies, we can expand our process control solutions for semiconductor manufacturing processes, while extending our reach to blue-chip end users in flat panel display, data storage, pharmaceutical, and other markets with advanced processes. As cycle times shorten and processes become more complex, the costs of contamination and the requirements for data increase. Tight process control is required to reduce defects and improve yields. We believe that an increasing percentage of the capital equipment budget is going to be spent to improve uptime, yield, and throughput, and return on invested capital."

Ion Systems' ionization technology controls electrostatic charge to reduce process contamination and improve yields, which complements MKS' process monitoring and control technologies. Umetrics' multivariate data analysis and modeling software converts process data into useable information for yield improvement, when linked with MKS' open and modular platform of process sensors and data collection, integration, data storage, and visualization capabilities.

MKS expects the net effect of these acquisitions to be slightly accretive on an operating or non-GAAP earnings basis in the first quarter of 2006. MKS has historically been acquisitive, and MKS' management believes the presentation of non-GAAP financial measures, which exclude the costs associated with acquisitions and other special items, is useful to investors for comparing prior periods and analyzing ongoing business trends and operating results.

MKS Instruments, Inc. is a leading worldwide provider of process control solutions for advanced manufacturing processes such as semiconductor device manufacturing; thin-film manufacturing for flat panel displays, data storage media, architectural glass and electro-optical products; and technology for medical imaging equipment. Our instruments, components and subsystems incorporate sophisticated technologies to power, measure, control, and monitor increasingly complex gas related semiconductor manufacturing processes, thereby enhancing our customers' uptime, yield and throughput, and improving their productivity and return on invested capital.

Contact:
Ronald Weigner
Vice President & Chief Financial Officer
978.284.4446.

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