CHANDLER, Ariz. and SOUTH SAN FRANCISCO, Calif., Dec. 13 -- Amkor Technology, Inc. (Nasdaq: AMKR) and PSi Technologies Holdings, Inc. (Nasdaq: PSIT) have signed a broad, multi-year patent license agreement that allows PSi to practice under Amkor's portfolio of MicroLeadFrame(R) patents and will grant Amkor access to the intellectual property being developed by PSi related to its PowerQFN(TM) technology.

MicroLeadFrame®, or MLF®, is Amkor's proprietary version of an integrated circuit package with the generic nomenclature of QFN, which stands for "quad, flat-pack, no lead." Amkor's MLF® package is a lead frame-based, nearly chip-scale package with an exposed die paddle and leads on the bottom of the package, providing excellent thermal and electrical performance. Introduced in the late 1990s, Amkor's MicroLeadFrame® package has seen accelerating adoption by IC suppliers as a cost-effective alternative for conventional low lead-count packages. In the past three years, Amkor has shipped more than two billion MLF® packages. According to Terry Davis, Amkor's vice president for MicroLeadFrame® packages, "This agreement recognizes Amkor's substantial investment in MLF® technology and intellectual property."

PSi's PowerQFN(TM)-type package utilizes heavy aluminum wire, solder die attach, clip leads and an encapsulated Molded Array Package Singulation (MAPS) approach, geared specifically for the higher voltage and thermal requirements of the power semiconductor market. PowerQFN packages with solder die attach and clip-leads have enhanced electrical device performance through reduced parasitics and thermal resistance. PSi anticipates beginning production on its PowerQFN family of packages during the first quarter of 2005.

"The introduction of a QFN-type package represents an ongoing commitment by PSi to develop products that meet increasingly sophisticated and demanding packaging requirements of PSi's power semiconductor customers," said Arthur J. Young, Jr., Chairman & CEO of PSi Technologies. "This agreement, which provides PSi with the flexibility and option to utilize Amkor's MLF® patents according to the thermal and voltage requirements of PSi's customers, is a key step towards fulfilling PSi's Packaging Power Solutions(TM) commitment."

About Amkor:

Amkor Technology, Inc. is a leading provider of contract semiconductor assembly and test services. The company offers semiconductor companies and electronics OEMs a complete set of microelectronic design and manufacturing services. More information on Amkor is available from the company's SEC filings and on Amkor's web site:

About PSi Technologies:

PSi Technologies is a focused independent semiconductor assembly and test service provider to the power semiconductor market. The company provides comprehensive package design, assembly and test services for power semiconductors used in telecommunications and networking systems, computers and computer peripherals, consumer electronics, electronic office equipment, automotive systems and industrial products. Their customers include most of the world's major power semiconductor manufacturers. More information on PSi is available from the company's SEC filings and on PSi's web site:

     Amkor Contacts:
     Jeffrey Luth                       Martijn Pierik
     Amkor Technology, Inc.             Positio Public Relations, Inc.
     Phone: 480-821-2408 ext. 5130      Phone: (408) 453-2400          

     PSi Technologies Contacts:
     Edison G. Yap, CFA                 Amy Cozamanis
     PSi Technologies Holdings          Financial Relations Board
     Phone: (63 917) 894 1335           Phone: (310) 854-8314

Safe Harbor Statement

This press release contains forward-looking statements made by Amkor and PSi that involve risks and uncertainties. These statements include, but are not limited to, the duration of the license agreement between Amkor and PSI and the anticipated production of the PowerQFN family of packages beginning in the first quarter of 2005. Actual results and outcomes may differ materially. Factors that might cause a difference include, but are not limited to, the terms and conditions of the license agreement between Amkor and PSI, factors relating to the pace of development and market acceptance of PSi's products and the power semiconductor market generally, commercialization and technological delays or difficulties, the impact of competitive products and technologies, competitive pricing pressures, manufacturing risks, the possibility of PSi's products infringing patents and other intellectual property of third parties, product defects, costs of product development, manufacturing and government regulation, risks inherent in emerging markets, including but not limited to, currency volatility and depreciation, restricted access to financing and political and social unrest. PSi and Amkor undertake no responsibility to update these forward-looking statements to reflect events or circumstances after the date hereof. More detailed information about potential factors that could affect the financial results of Amkor and PSi is included in the documents filed by Amkor and PSi from time to time with the Securities and Exchange Commission.