SANTA CLARA, Calif.--AMS Lithography's photomask design company here said it is suing Avant! Corp. again for violating its U.S. patents covering "scattering bars" used in optical proximity correction (OPC).
ASML MaskTools said it had settled a previous lawsuit against Avant! in February 1999, but now it is accusing the Fremont, Calif., design automation company of breaching that agreement. ASML MaskTools said the new lawsuit was filed under seal to protect the confidentiality of the 1999 suit settlement.
In the suit, Santa Clara-based ASML MaskTools said it was seeking damages and a court order instructing Avant! to abide by the terms of the year-old agreement. An immediate response from Avant! was unavailable.
OPC technology and phase-shifting techniques are becoming critical technologies in photomasks as chip makers shrink device feature sizes below the wavelength of exposure light. Late last year, ASML MaskTool and Mentor Graphics Corp. announced an alliance to create an integrated solution to extend the use of optical exposure technology and to verify the manufacturability of complex IC designs that use subwavelength geometries (see Dec. 9 story).