May 8, 2007 – Pall Corp. says it has filed another lawsuit against Entegris Inc., claiming the company’s filter cartridge lines infringe upon four Pall patents.

The new suit follows a new patent award to Pall in March for filters with an internal configuration that the company claims minimizes process fluid loss, for applications including filtering photoresist liquid. The other patents at issue in this suit, ranging in date from 1996-2000, refer to filters with overlaid pleats.

In a statement, Entegris says it “sees no merit” in the new allegations targeting its point-of-use filtration products, though it claims it hasn’t formally been served in the new matter. Still, based on court documents, Entegris says that the claim rests on Pall’s “information and belief” that Entegris’ Impact photoresist filters violate its patents, which Entegris asserts are based on four US patents held by Entegris.

The two companies have been disputing filter patents since 2003, litigation that Entegris inherited through its 2005 merger with Mykrolis. Both companies filed patent infringement claims against the other in early 2006.