HSINCHU, Taiwan, and BLOOMINGTON, Minn., December 4, 2025 – United Microelectronics Corporation (NYSE: UMC: TWSE: 2303)(“UMC”), a leading global semiconductor foundry, and Polar Semiconductor, LLC (“Polar”), a U.S.-owned and operated foundry specializing in high-voltage, power, and sensor technologies, today announced they have signed a Memorandum of Understanding (MOU) to explore collaboration on delivering scalable U.S.-based 8-inch production of high-quality wafers that are essential across pillar industries including automotive, data centers, consumer electronics, and aerospace & defense.

Under the MOU, Polar and UMC will identify devices for Polar to manufacture at its recently expanded 8-inch facility in Minnesota. By combining Polar’s proven manufacturing capabilities with UMC’s comprehensive 8-inch technology portfolio and global customer base, this partnership is set to drive growth for both companies while supporting customers’ multi-sourcing strategies. In addition, the collaboration will strengthen 8-inch wafer manufacturing in the U.S., contributing to supply chain resilience amid shifting geopolitical dynamics and ensuring a secure domestic supply of power semiconductors critical to automotive, electric grids, robotic manufacturing, data centers, and more.

Ken Obuszewski, Vice President of Marketing of Polar, said, “This partnership is aligned with Polar’s strategy to meet the growing demand for domestic manufacturing, including the need to onshore semiconductor solutions from U.S. and global customers. With deep foundry customer relationships and a robust portfolio of specialized technologies, partnership with UMC is proof of Polar’s capability to be a value-added silicon foundry in specialized technologies focused on power and sensors.”

Oliver Chang, Senior Vice President of Global Sales of UMC, said, “UMC is committed to enabling our customers’ success through a broad range of foundry technologies and geographically diverse manufacturing options. We are excited to collaborate with Polar to explore new applications and markets. This partnership directly addresses our customers’ needs for more made-in-USA chips, reflecting UMC’s dedication to delivering value through innovative solutions and mutually beneficial partnerships.”

About UMC

UMC (NYSE: UMC, TWSE: 2303) is a leading global semiconductor foundry company. The company provides high-quality IC fabrication services, focusing on logic and various specialty technologies to serve all major sectors of the electronics industry. UMC’s comprehensive IC processing technologies and manufacturing solutions include Logic/Mixed-Signal, embedded High-Voltage, embedded Non-Volatile-Memory, RFSOI, BCD etc. Most of UMC's 12-in and 8-in fabs with its core R&D are located in Taiwan, with additional ones throughout Asia. UMC has a total of 12 fabs in production with combined capacity of more than 400,000 wafers per month (12-in equivalent), and all of them are certified with IATF 16949 automotive quality standard. UMC is headquartered in Hsinchu, Taiwan, plus local offices in United States, Europe, China, Japan, Korea & Singapore, with a worldwide total of 20,000 employees. For more information, please visit: http://www.umc.com.

About Polar Semiconductor

Polar Semiconductor is a leading foundry specializing in high-voltage, power, and sensor semiconductor manufacturing for automotive, industrial, aerospace and defense, data center, and consumer applications. Based in Bloomington, Minnesota, Polar provides advanced BCD, BiCMOS, MOSFET, IGBT, Optical MEMS, Wide-Bandgap (GaN), and sensor process technologies and associated foundry design enablement, transfer, and characterization services. With decades of experience and a strong focus on quality, reliability, and innovation, Polar supports some of the world’s most demanding semiconductor customers. The company is currently expanding its capacity and capabilities to serve the growing demand for power electronics and next-generation technologies. For more information, visit www.polarsemi.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 introduction of new services and technologies, future outsourcing, competition, wafer capacity, 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. Further information regarding these and other risks is included in UMC’s filings with the U.S. Securities and Exchange Commission. UMC does not undertake any obligation to update any forward-looking statement as a result of new information, future events or otherwise, except as required under applicable law.