Hidden beneath AI chips, Chinese-made circuit boards raise national security concerns in U.S.

Printed circuit boards sit underneath nearly every chip, a quiet but crucial piece of the booming AI market. But nearly all AI circuit boards for Nvidia, Google, Apple and others are made in China, creating supply chain and national security vulnerabilities. The wars in Iran and Ukraine mean rising PCB demand and prices, but the military can only source them from the U.S. CNBC visited TTM, the largest U.S. circuit board maker, to see how PCBs are made and find out how new legislation could help.