GlobalFoundries just became TSMC's subcontractor for a key piece of every advanced AI chip package.
GlobalFoundries and TSMC signed a five-year, $2 billion agreement for GF to manufacture silicon interposers - the custom silicon that wires logic chiplets to high-bandwidth memory stacks - for TSMC's CoWoS-S advanced packaging process. Production will run out of GF's fab in Malta, New York, with volume output starting in the first half of 2028. The deal covers interposers only, not the bonding, substrate assembly, or testing that also goes into a finished CoWoS package. Neither company has disclosed planned capacity or how the $2 billion breaks down.
This is less about GlobalFoundries building bleeding-edge chips - it gave that up in 2018 - and more about it finding a profitable niche inside someone else's supply chain. It also slots into TSMC's push for a largely domestic AI chip pipeline: Arizona fabs for logic, Amkor's Peoria facility and TSMC itself for packaging, and now GF for interposers. Nobody has said whether GF's output will actually be used in the Arizona operation, or how assembly work will split between TSMC and Amkor.
Call it reshoring with caveats - the "made in America" label survives, but the HBM stacks inside the box still fly in from Korea or Japan, at least until Micron and SK hynix's own U.S. assembly plans land later this decade.