GaSonics International Ships 250th PEP System; Shipment Highlights GaSonics' Role as Leading Photoresist Removal System Provider.

Business Editors and High Tech Writers

SAN JOSE, Calif.--(BUSINESS WIRE)--June 28, 2000

GaSonics International Corp. (Nasdaq: GSNX), a leading supplier of photoresist and residue removal solutions, today announced the 250th shipment of its Performance Enhancement Platform (PEP) systems. The system was shipped to UMC, a world-leading semiconductor foundry, for its Taiwan-based Fab 8E. The PEP system, a PEP 3510A, will be used for photoresist removal processes necessary for the production of a variety of integrated circuit (IC) devices. This significant milestone illustrates the PEP's continued market success and further establishes GaSonics as a leading supplier of photoresist removal systems worldwide.

"In order to be successful, we need equipment that is not only flexible but also reliable. GaSonics' PEP system has proven itself in our other installations," said Mr. W.Y. Chen, UMC's vice president of Fab 8E. "The PEP 3510A gives us performance we can depend on day after day. We're pleased to receive this historic shipment."

With photoresist and residues having an increasing impact on both device performance and yields, chipmakers transitioning to device geometries of 0.18 micron and below need process solutions that perform a variety of advanced applications in photoresist and residue removal. "This 250th shipment is another excellent example of how GaSonics has responded to this need with the stability and flexibility necessary to precisely remove unwanted materials within highly complex production environments," said Asuri Raghavan, president and CEO of GaSonics. "By being able to accommodate multiple process modules and perform a variety of applications, we believe our PEP platform is ideal for any chipmaker looking for a production-proven photoresist removal system to meet its future manufacturing challenges."

Designed for optimum process flexibility, the PEP's dual-chamber cluster configuration accommodates interchangeable photoresist and residue removal modules that enable parallel, sequential or independent processing. Building on these core capabilities, GaSonics has designed the PEP to address manufacturing challenges with the inclusion of integrated standard mechanical interface (SMIF), generic equipment model (GEM) software and automatic guided vehicle (AGV) features to provide the most advanced capabilities achievable.

GaSonics' PEP 3510A is a versatile microwave downstream photoresist removal system, designed for clean, damage-free removal of photoresist. The PEP 3510A utilizes a combination of platen and lamp wafer heating, resulting in excellent ash rate and uniformity. The robust system excels in bulk photoresist removal and descum applications requiring either oxidizing or reducing chemistries. One of GaSonics' most dependable tools, the PEP 3510A routinely delivers superior uptime.

Management would like to remind readers that any forward looking statements in this press release are always subject to risks in this ever-changing marketplace, including the cyclicality in the markets served by the Company's customers, market acceptance of new and enhanced versions of the Company's products, performance of the Company's products, the stability of the Asia-Pacific region, the mix of products sold, the timing of significant orders and delays, deferrals, reschedulings or cancellations of orders, the relationship of operating expenses to revenue, and the proportion of direct sales and sales through distributors. For a more detailed discussion of these and associated risks, the Company refers the readers to documents filed with the Securities and Exchange Commission (SEC) from time to time, specifically the most recent Form 10-K and Form 10-Q.

UMC, a world leading semiconductor foundry, operates fabs in Taiwan and Japan and has two 12-inch fabs under construction. UMC is a leader in foundry technology and expects capacity to reach 2.4 million wafers per year in 2000 with more than half in advanced 0.18- and 0.25-micron technology. UMC's Worldlogic standard 0.13-micron is on target for introduction for the year 2000. Global sales were $1.75 billion in 1999. UMC has marketing and customer support offices located in the United States, Japan and the Netherlands. UMC can be found on the web at www.umc.com

GaSonics International (Nasdaq: GSNX) is a leading developer and global supplier of photoresist and residue removal technologies. The Company's products, which are sold to leading semiconductor manufacturers worldwide, allow customers to integrate manufacturing process steps as well as increase yields and throughput. GaSonics also provides low-pressure chemical vapor deposition systems for the flat panel display industry. Headquartered in San Jose, Calif., GaSonics supports its installed base of more than 2,000 single-wafer systems through a global sales and support network. Additional information about the Company is available on GaSonics' website, located at www.gasonics.com