Hsinchu, Taiwan, October 9, 2002 - United Microelectronics Corporation (NYSE: UMC; TSE: 2303), a world leading semiconductor foundry, has won a ruling against Taiwan's Silicon Integrated Systems ("SiS") in an investigation before the United States International Trade Commission (the "ITC"). In a Notice of Final Determination and Issuance of Limited Exclusion Order issued in Washington DC on October 7, 2002, the ITC ruled that SiS is manufacturing products using a patented UMC process in violation of United States law. The Limited Exclusion Order directs the U.S. Customs Service to bar the entry of all SiS products made with the infringing process into the United States.

Infringing SiS chipsets and graphics chips, and all motherboards containing infringing SiS products, are to be barred from importation into the United States immediately following the law-mandated 60-day period for Presidential review of the decision. During this review period, infringing SiS products may be imported into the United States only if a bond is posted with the U.S. Customs Service in the amount of 100% of product value for each chipset and graphics chip, and 39% of product value for each motherboard containing those products. If the ITC's decision stands after the 60 days have elapsed, infringing SiS products will be barred from importation or sale in the United States until the year 2017.

"We believe in the fundamental importance of protecting intellectual property rights, whether it be our customers' or our own," said Robert Tsao, Chairman of UMC. "The United States FTC decision in favor of UMC underscores the value of intellectual property rights as a whole and sends a clear message that infringement on another company's proprietary technology will not be tolerated."

UMC has also asserted claims for infringement of the '345 Patent against SiS in a civil lawsuit in California's U.S. District Court, in which UMC seeks financial damages and other relief from SiS for patent infringement, misappropriation of trade secrets and other unlawful conduct. In that case, UMC alleges that SiS hired UMC engineers and improperly used proprietary UMC information to develop the technology SiS required to enter the semiconductor manufacturing business, in systematic violation of UMC's intellectual property rights.