Vice Chairman Peter Chang to retire in October and remain as senior consultant; Appointment of Chief Operating Officer and Senior Vice President to focus on specific needs of 12-inch and 8-inch foundry customers

Hsinchu, Taiwan, August 17, 2007 - UMC (NYSE: UMC), a leading global semiconductor foundry, today announced that UMC Vice Chairman Peter Chang will retire from his current position, effective October 1st, due to the approach of his planned retirement age. Vice Chairman Chang has been a very important member of UMC's management team over the last 10 years, and served in many key positions, including that of CEO. UMC has benefited greatly from his contribution over the years and will continue to leverage his wealth of experience in the role of senior consultant to UMC after his retirement.

UMC also announced a reorganization of its management structure to better serve its diverse customer base. Executive Vice President Dr. Shih-wei Sun, currently head of UMC's Central Research and Development Division and Fab 12A, will take the position of Chief Operating Officer (COO) for 12-inch operations, and UMC vice president W. Y. Chen has been appointed to the position of Senior Vice President in charge of UMC's 8-inch and 6-inch operations.

The establishment of separate organizations to manage the different technology operations is intended to better serve the specific and unique customer requirements that exist for 12-inch and 8-inch manufacturing technologies. As COO for 12-inch operations, Dr. Sun will be responsible for fab operations, sales, and the profit/loss for 12-inch technologies. Senior Vice President Chen will have the same responsibilities pertaining to 8 and 6-inch technologies. Both men will report directly to Dr. Jackson Hu, UMC's Chairman and CEO.

UMC (NYSE: UMC, TSE: 2303) is a leading global semiconductor foundry that manufactures advanced system-on-chip (SoC) designs for applications spanning every major sector of the IC industry. UMC's SoC Solution Foundry strategy is based on the strength of the company's advanced technologies, which include production proven 90nm, 65nm, mixed signal/RFCMOS, and a wide range of specialty technologies. Production is supported through 10 wafer manufacturing facilities that include two advanced 300mm fabs; Fab 12A in Taiwan and Singapore-based Fab 12i are both in volume production for a variety of customer products. The company employs approximately 13,000 people worldwide and has offices in Taiwan, Japan, Singapore, Europe, and the United States. UMC can be found on the web at http://www.umc.com.