Taiwan Semiconductor Manufacturing Company (TSMC), which is suing mainland rival Semiconductor Manufacturing International Corp (SMIC), has found itself at the centre of another patent infringement suit involving rival chipmakers in the United States. Last week, UniRAM Technology filed a suit in a US district court in California, alleging Monolithic System Technology (MoSys) had misappropriated trade secrets and infringed upon its patents. According to UniRAM's suit, it provided trade secret information to TSMC between 1996 and 1997. The suit then claims that MoSys obtained UniRAM's trade secrets from the Taiwanese chipmaker in an unknown manner. TSMC, the world's largest contract chipmaker, was not named as a defendant in the suit. Company spokesman Tzeng Jin-hao said he was unaware of the suit and could not comment. Mr Tzeng would also not confirm whether UniRAM or MoSys were TSMC customers. MoSys denied the patent infringement claims. 'MoSys believes that UniRAM's complaint lacks merit and intends to vigorously defend itself,' the company said. The suit could prove troublesome for TSMC, which will likely be required to provide testimony as UniRAM attempts to prove MoSys improperly obtained its trade secrets from the contract chipmaker. The Taiwanese company has filed a suit in the same court, accusing SMIC of poaching more than 100 staff to gain access to TSMC patents and rapidly build its technology know-how. It added to those charges last month, accusing SMIC of luring TSMC employees with hefty stock awards and options, and inducing them to steal trade secrets. TSMC has sought to portray itself as the victim of a massive intellectual property theft. It has compared its case to a similar dispute between Cadence Design Systems and Avant Corp, in which the latter was forced to settle for US$265 million.