July 26, 2001 — SAN FRANCISCO, CA — Entegris, Inc. has signed a definitive agreement to acquire all shares of Atcor Corporation for an undisclosed cash payment. Atcor Corporation is the supplier of precision cleaning systems and cleaning services providing a variety of cleaning/drying technologies to the world’s largest semiconductor and hard disk drive manufacturers.

Atcor also serves the medical, automotive, flat panel, optical and precision part industries. Atcor Corporation’s annual sales are approximately $18 million.

“We’re pleased to bring our customers and the industry a partnership of Atcor and Entegris,” said Michael Wright, Entegris president, microelectronics group.

“With Atcor’s leadership in product cleaning systems and services, Entegris rounds out its ability to give customers an outsourced program for wafer, device and disk transportation and protection. Bringing “

Atcor cleaning systems and services completes the gap in the wafer handling program Entegris is offering its customers. With this addition, Entegris is beginning the Silicon Delivery Systems and Services (SDS2) program, offering a new approach for silicon, device and disk handling. This new market approach is driven by the needs of the user and includes such items as handling for raw wafer processing and shipping, wafer processing, finished wafer shipping and handling, product cleaning systems or services, logistics management and certified reuse and recycle. Customer’s can choose between on-site and off-site programs.