The two patents (United States Patent Nos. 4,702,808 and 5,131,941) were filed with the US Patent Office by Jerome Lemelson, a prolific inventor, in 1957 and 1964 and finally issued in 1987 and 1992 respectively. They passed through the Lemelson Medical, Educational and Research Foundation Limited Partnership in 2001 to Syndia.

The first patent appears to be related to laser-enhanced chemical reaction; the second to plasma-enhanced chemical vapor deposition.

"We fully respect the legitimate intellectual property rights of others; however, we are committed to defending the company and its customers against invalid claims whenever they appear. We firmly believe that TSMC does not infringe and that these Syndia patents are invalid and unenforceable," said Dick Thurston, vice president and general counsel for TSMC.

The suit was filed after legal counsel for Syndia advised TSMC that it intended to file patent infringement claims based on two patents and were allegedly assigned to Syndia.

The suit was filed by TSMC, Ltd., TSMC North America, and WaferTech LLC after learning that Syndia had sent letters to customers requesting the payment of a "lump-sum licensing offer."

TSMC feels that Syndia's actions are designed to interfere with TSMC's customer relationships, the company said.