SAN JOSE, Calif. and HSINCHU, Taiwan-April 11, 2005 - The X Initiative and UMC (NYSE: UMC, TSE:2303), a world leading semiconductor foundry, today announced that UMC is the first pure-play foundry to release qualified design rules for X Architecture-based chip designs at the 90-nanometer process node. UMC is now ready to accept X Architecture designs from fabless semiconductor companies and its integrated device manufacturers (IDM) partners for fabrication at the 90-nanometer process node.

The X Architecture represents a new way of orienting a chip's microscopic interconnect wires with the pervasive use of diagonal routes, in addition to traditional right-angle "Manhattan" routing. By enabling designs with significantly less wirelength and fewer vias, or connectors between wiring layers, the X Architecture can provide significant improvements in chip performance, cost and power consumption.

"UMC continues to demonstrate its leadership by supporting the X Architecture and its use of diagonal wiring to gain performance and cost advantages," said Patrick T. Lin, chief SoC architect at UMC. "Through our most recent effort, fabless semiconductor companies can develop 90-nanometer chips that incorporate diagonal routing with the confidence that UMC will support their designs throughout the design and manufacturing cycle."

In 2003, UMC became the first pure-play foundry to join the X Initiative, as well as the first to announce its readiness to accept X Architecture based designs for fabrication at 130-nanometer process nodes.

"UMC's announcement of the availability of world-class manufacturing for 90-nanometer X Architecture designs bodes well for this 'year of first X products'," noted Aki Fujimura, X Initiative steering group member and chief technology officer, New Business Incubation, at Cadence Design Systems, Inc. "The performance and cost benefits of the X Architecture, coupled with the advanced 90-nanometer process, are a potent combination for the performance-demanding and cost-conscious fabless market."

The X Architecture, the first production-worthy approach to the pervasive use of diagonal interconnect, reduces the total interconnect, or wiring, on a chip by up to 20 percent and via-counts by up to 30 percent, resulting in significant improvements in chip performance, power and cost. For the past 20 years, chip design has been primarily based on the de facto industry standard "Manhattan" architecture, named for its right-angle interconnects resembling a city-street grid. The X Architecture rotates the primary direction of the interconnect in the fourth and fifth metal layers by 45 degrees from a Manhattan architecture. The new architecture maintains compatibility with existing cell libraries, memory cells, compilers and IP cores by preserving the Manhattan geometry of metal layers one through three.

The X Initiative, a group of leading companies from throughout the semiconductor industry, is chartered with accelerating the availability and fabrication of the X Architecture, a revolutionary interconnect architecture based on the pervasive use of diagonal routing. The X Initiative's five-year mission is to provide an independent source of education about the X Architecture, to facilitate support and fabrication of the X Architecture through the semiconductor industry design chain, and to survey usage of the X Architecture to track its adoption. Representing leaders spanning the entire design-to-silicon supply chain, X Initiative members include: Applied Materials, Inc.; ARM; ASML Netherlands B.V.; Cadence Design Systems, Inc.; Canon U.S.A. Inc.; Dai Nippon Printing (DNP); DuPont Photomasks, Inc.; GDA Technologies, Inc.; HPL Technologies, Inc.; Hoya Corporation; IN2FAB Technology Ltd.; Infineon Technologies AG; JEOL, Ltd.; KLA-Tencor Corporation; Leica Microsystems AG; Matsushita Electric Industrial Co., Ltd.; MicroArk Co. Ltd.; Nikon Corporation; NuFlare Technology Inc.; PDF Solutions, Inc.; Photronics, Inc.; Prolific Inc.; RUBICAD Corporation; Sagantec; Sanyo Electric Co., Ltd.; Silicon Logic Engineering, Inc.; SiliconMap, LLC.; Silicon Valley Research Inc.; STMicroelectronics; Sycon Design, Inc.; Tensilica, Inc.; Toppan Printing Co.; Toshiba Corporation; Trecenti Technologies, Inc.; TSMC; UMC; Virage Logic, Inc.; Virtual Silicon Technology, Inc.; Zenasis Technologies, Inc.; and Zygo Corporation. Membership is open to all companies throughout the semiconductor design chain. Materials can be found at http://www.xinitiative.org.

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 90nm copper, 0.13um copper, and mixed signal/RFCMOS. UMC is also a leader in 300mm manufacturing; Fab 12A in Taiwan and Singapore-based UMCi are both in volume production for a variety of customer products. UMC employs over 10,500 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.

This release contains forward-looking statements (including, without limitation, information regarding semiconductor design, production and performance improvements resulting from the X Architecture, the compatibility of the X Architecture with current technology, the future success of X Architecture technology and the ability of certain of the X Initiative members to support the X Architecture) that involve risks and uncertainties that could cause the results of X Initiative members and other events to differ materially from managements' current expectations. Actual results and events may differ materially due to a number of factors including, among others: future strategic decisions made by the X Initiative members; failure of the X Architecture to enable the production of designs that are feasible and competitive with current designs or future alternatives; future strategic decisions made by X Initiative members or others that inhibit the development of the X Architecture; demand for advanced semiconductors that are developed using the X Architecture; cost feasibility of the production of semiconductors designed using the X Architecture; and the rapid pace of technological change in the semiconductor industry. The matters discussed in this press release also involve risks and uncertainties described in the most recent filings of the X Initiative members with the Securities and Exchange Commission. The X Initiative members, individually or collectively, assume no obligation to update the forward-looking information contained in this release.

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.

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