TSMC Taps Xintec for CoWoS Packaging in Seven-Year Deal Running to 2033

TSMC has locked in Xintec Inc. for seven years to build and operate a production line for the on-substrate portion of its CoWoS advanced packaging, usually shortened to oS. The agreement runs through December 31, 2033, and Xintec's board signed off on November 13, 2026. Under the arrangement, TSMC supplies the building inside its Central Taiwan Science Park facility while Xintec brings the equipment and the workers to run it. Initial mass production is targeted for 2029.

Xintec is hardly an outside hire. TSMC owns approximately 41% of the company, and Xintec already pulls more than 70% of its revenue from TSMC-related work, largely in testing and related services. This deal pushes it deeper into back-end packaging. To fund the buildout, Xintec plans to raise NT$15 billion through convertible bonds, with the money earmarked for the new line's equipment and systems.

CoWoS — Chip-on-Wafer-on-Substrate — stacks logic dies and high-bandwidth memory on a silicon interposer that acts as a dense layer of wiring linking everything together. It has become TSMC's flagship technology for AI and high-performance computing chips, and one of the industry's most stubborn chokepoints, with Nvidia and AMD among the major customers relying on it.

The Xintec line is one piece of a wider push. TSMC has announced a $2 billion deal with GlobalFoundries to make silicon interposers in the US, with that ramp targeted for 2028, and has acquired display plants from AUO to gain more cleanroom space. Supply constraints for CoWoS are projected to ease gradually through 2028, which makes the 2029 start date on the Xintec line notable — and the contract's run into 2033 even more so. For Xintec, the trade-off is a long anchor contract against growing dependence on a single customer, financed with new debt. Milestones to watch: the NT$15 billion raise, construction at the Central Taiwan Science Park site, and whether the 2028 GlobalFoundries ramp lands on schedule.