For more information, contact:

Jim Donaldson Advanced Energy Industries, Inc. 970.407.6374 jim.donaldson@aei.com

Marna Shillman Advanced Energy Industries, Inc. 970.407.6280 marna.shillman@aei.com

FORT COLLINS, Colo., Sept. 16, 2003—Advanced Energy Industries, Inc. (Nasdaq: AEIS) today announced that its Aera mass flow controllers (MFCs) have been selected for required retrofits on poly etch systems by one of the world’s leading semiconductor manufacturers. The selection was awarded to the Aera FC-D980 Series, which has exhibited superior performance, reliability and value in a wide range of environments. The FC-D980 Series was selected after rigorous pilot-line testing was completed. The chip maker will retrofit the Aera MFCs into each of its production lines in all fabs around the world that run this same poly etch process.

Advanced Energy Chairman and CEO Doug Schatz noted, “Given our customers’ exacting evaluation processes, the selection of our MFC to replace a competitive product is a strong testimonial of AE’s technology leadership.”

“This customer, one of the top five chip makers in the world, was experiencing MFC-related issues on a critical poly etch process,” said Advanced Energy Vice President and General Manager of the Control Systems and Instrumentation group Steve Rhoades. “We worked closely with this customer throughout the qualification process and the Aera FC-D980 easily demonstrated improved flow accuracy, stability, repeatability and value.”

With an installed base of nearly 70,000 units, the Aera FC-D980 series is one of the world’s leading digital MFCs. The series features a CPU that can store calibration curves for up to eight different gases and up to 11 calibration points for each gas, enabling enhanced accuracy and linearity, without degradation, throughout the operating range. The FC-D980 Series MFCs can be easily reprogrammed for different gases and full-scale flows using a PC, and can be operated in digital, analog or analog/digital mode. The products also provide impressive flexibility of gas and flow selection. Their multi-gas and multi-range performance significantly reduces spare MFC inventory.

About Advanced Energy

Advanced Energy is a global leader in the development and support of critical technologies for high-technology manufacturing processes used in the production of semiconductors, flat panel displays, data storage products, compact discs, digital video discs, architectural glass, and other advanced product applications.

Leveraging a diverse product portfolio and technology leadership, AE creates solutions that maximize process impact, improve productivity and lower cost of ownership for its customers. This portfolio includes a comprehensive line of technology solutions in power, flow and thermal management, plasma and ion beam sources, and integrated process monitoring and control for original equipment manufacturers (OEMs) and end-users around the world.

AE operates in regional centers in North America, Asia and Europe, and offers global sales and support through direct offices, representatives and distributors. Founded in 1981, AE is a publicly held company traded on Nasdaq National Market under the symbol AEIS. For more information, please visit our corporate Website: www.advanced-energy.com