Plaintiffs Praxair, Inc. and Praxair Technology, Inc. (collectively “Praxair”) brought suit alleging that defendants ATMI, Inc. and Advanced Technology Materials, Inc. (collectively “ATMI”) had infringed three patents: U.S. Patent No. 6,007,609 (the “’609 patent”); U.S. Patent No. 6,045,115 (the “’115 patent”), and U.S. Patent No. 5,937,895 (the “’895 patent”). The district court entered a final judgment concluding that claims 1, 2, 6, 7, and 8 of the ’609 patent and claims 18 and 20 of the ’115 patent were not invalid and were infringed; declaring the ’609 and ’115 patents unenforceable due to inequitable conduct; and declaring claims 1, 3, 4, 5, 7, and 8 of the ’895 patent invalid for indefiniteness. Praxair, Inc. v. ATMI, Inc., No. 03-1158-SLR (D. Del. July 2, 2007).
We affirm the district court’s determination that the ’115 patent is unenforceable due to inequitable conduct. We reverse the district court’s unenforceability conclusion with respect to the ’609 patent. We affirm the determination that the asserted claims of the ’609 patent were not proven invalid, vacate the determination of infringement with respect to the ’609 patent (because the district court used an incorrect claim construction), and remand for a determination as to infringement of the ’609 patent under the correct claim construction. We also reverse the district court’s judgment of invalidity for indefiniteness of the asserted claims of the ’895 patent and remand for further proceedings. As to Praxair’s appeal, we thus affirm-in-part, reverse-in-part, and remand. We dismiss ATMI’s cross-appeal as improper.
