Apple Watch Chips Now Being Made in the U.S. for the First Time

Apple has expanded its production footprint in the United States, with its S9 chip for the Apple Watch now reportedly being manufactured at TSMC's facility in Arizona.

According to technology columnist Tim Culpan, TSMC has now started producing Apple's S9 System-in-Package (SiP) chip near Phoenix, Arizona at its Fab 21 plant. The company commenced production of the A16 Bionic chip for the iPhone 15 and ‌iPhone‌ 15 Plus at the facility last year.

The S9 debuted in the Apple Watch Series 9 in late 2023, based on processing features derived from the A16 Bionic chip. Both products are produced using TSMC's 4-nanometer process technology, known simply as "N4." This shared technological foundation reportedly allowed TSMC to efficiently adapt its Arizona production line to accommodate the S9 alongside the A16. While the Apple Watch Series 9 is now out of production, the S9 chip is still used in the Apple Watch Ultra 2, which was introduced at the same time.

While the A16 Bionic has been in production at Fab 21 since September 2024, the addition of the S9 SiP reflects an accelerated ramp-up in operations at the Arizona facility. The Arizona plant represents TSMC's first major semiconductor manufacturing site outside Taiwan, but production capacity at the facility has remained in its early stages.

The current operational phase (Phase 1A) has a monthly output of approximately 10,000 wafers. These wafers are shared between the Apple A16 and S9 chips, and other clients such as AMD. Each wafer can yield hundreds of chips, depending on die size, design, and production efficiency. The completion of Phase 1B is expected to double the facility's capacity to 24,000 wafers per month early this year.