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Fort Collins, Colorado (May 15, 2003)—
Advanced Energy Industries, Inc.
Advanced Energy Industries, Inc. (Nasdaq: AEIS) today announced that, contrary to allegations in a complaint filed on May 14, 2003 by MKS Instruments, Inc., Advanced Energy is confident that Xstream™, its new reactive gas generator product, is not in violation of any MKS patent. In May 2002, a Delaware court clearly defined the limits of the MKS technology and its 6,150,628 patent. Advanced Energy respects those limits, and designed its new product to avoid infringement of any MKS patent based upon the advice of a team of independent experts. The four additional patents that have issued to MKS since the time of the Delaware litigation are continuations of the 6,150,628 patent based upon the same technology.