HSINCHU, Taiwan--April 19, 2006 - UMC, (NYSE: UMC, TSE: 2303) a leading global semiconductor foundry, today announced the delivery of a new SONOS memory to Solid State System Co. This new memory adopts advanced SONOS dielectric storage technology, effectively enhancing program speed as compared to conventional SONOS cells and conventional NAND type flash. UMC's experience in SONOS Thin Film development allowed its R&D team to deliver the 0.18um memory cell during its first cut, followed by completion of the pilot run for the 256Mb OTP/MTP memory product. This memory offers cost-competitive manufacturing, lower power consumption, and equivalent Program/Erase performance and reliability.

Joe Ko, vice president of the Specialty Technology Division at UMC, said, "UMC has been working on flash technology for many years for several customers' flash products, including commodity flash as well as embedded flash/EEPROM. This latest success with Solid State System Co. for the delivery of their SONOS product reaffirms UMC's solid technology foundation and knowledge base in the area of flash technology."

SONOS technology has been gaining interest in recent years because of its aggressively small cell size, lower voltage operation, and simple manufacturability compared to conventional types of flash technology such as NAND. These important features allow SONOS to be used for many high-density applications for storage media. SONOS memory cells can also be easily integrated into generic logic platforms.

To address the most difficult aspect in scaling for traditional SONOS technology--when the channel length becomes smaller--UMC uses an innovative method in its program current as opposed to the hot electron method used by conventional SONOS. This results in the lower power consumption exhibited by UMC's SONOS technology.

Cheng Liou, vice president of Solid State System Co., said, "UMC's experience in flash technology was a key factor for us in deciding on a foundry partner. By leveraging the combination of our patented memory cell technology and our design team, UMC's expertise in SONOS technology and its process development team, the efforts and decision from both sides have proven fruitful, demonstrated by the first pass silicon success of our first product. As we move this current product line to volume production, we are also working with UMC to develop high capacity SONOS memory products on advanced process technology."

Technology teams on both sides will also collaborate on the development of a new type of SONOS memory cell and the reduction of manufacturing cost.

Solid State System Co., founded in 1998, is a fabless IC design house in Taiwan. With experience and knowledge in Non-Volatile Memory, Solid State System has successfully delivered Flash Storage controllers to world-class customers. The company is located in Jubei, Taiwan. More information can be found on the web at http://www.3system.com.tw

UMC (NYSE: UMC, TSE: 2303) is a leading global semiconductor foundry that manufactures advanced process ICs for applications spanning every major sector of the semiconductor industry. UMC delivers cutting-edge foundry technologies that enable sophisticated system-on-chip (SoC) designs, including volume production 90nm, industry-leading 65nm, and mixed signal/RFCMOS. UMC's 10 wafer manufacturing facilities 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 12,000 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.

Note From UMC Concerning Forward-Looking Statements
Some of the statements in the foregoing announcement are forward looking within the meaning of the U.S. Federal Securities laws, including statements about future outsourcing, wafer capacity, technologies, business relationships and market conditions. Investors are cautioned that actual events and results could differ materially from these statements as a result of a variety of factors, including conditions in the overall semiconductor market and economy; acceptance and demand for products from UMC; and technological and development risks.