TSMC Taps GlobalFoundries for CoWoS Silicon Interposer in Five-Year, $2B Deal

TSMC has signed a five-year agreement worth approximately $2 billion with GlobalFoundries to produce silicon interposers used in its CoWoS advanced packaging, marking the first time the chipmaker has outsourced this key AI packaging component. The interposers will be manufactured at GlobalFoundries' facility in New York State, with production ramping up in the first half of 2028.

Silicon interposers serve as a critical bridge between AI processors and high-bandwidth memory (HBM), enabling high-speed data transmission between different chips within a single package. The move comes as AI chips integrate more memory and computing units, increasing demand for advanced packaging capacity and interconnect technology.

Industry observers said the long-term agreement reflects TSMC's effort to secure sufficient interposer supply amid strong AI-driven demand for advanced packaging. TSMC has doubled its CoWoS capacity for three consecutive years and previously outsourced the CoW process to assembly and test houses such as ASE Technology. The new deal extends its outsourcing strategy to silicon interposers and adds a US-based supply source for the critical component.

For GlobalFoundries, the agreement represents a significant entry into the AI advanced packaging materials space through its New York fabs. For TSMC, the five-year deal provides long-term supply assurance beyond its own capacity expansion. Taiwanese foundries United Microelectronics (UMC) and Powerchip are also expanding silicon interposer capacity, but TSMC's decision to award the largest outsourced order to a US-based foundry means competition for incremental interposer orders will no longer be limited to Taiwanese suppliers.