Tokyo Seimitsu Co., Ltd. (Accretech) — AI supply-chain exposure

Tokyo Seimitsu, which trades as Accretech, makes the machines that test and finish wafers: probers that contact each die to check it works, plus dicing saws, grinders and CMP tools that thin, cut and planarise the wafer after the transistors are built. It spans both the metrology-heavy wafer-test step and the back-end processing that turns a finished wafer into singulated chips.

Its structural hook is wafer probing, where it is one of only a couple of credible suppliers worldwide, and wafer grinding, which matters more as chips are thinned for stacking in advanced packages and high-bandwidth memory. The model ties it to test and burn-in capacity because probing is an unavoidable gate every logic and memory die must pass before it can ship.