The Fragile Foundation of the AI Revolution

Every chip starts as two inputs: silicon wafers and extreme ultraviolet (EUV) photoresists, the chemicals that transfer circuit patterns onto them. Four companies make nearly all the wafers and four make nearly all the photoresists.

180 tons, 457,329 parts, and up to $480M each. ASML's EUV scanner is the only machine that can print transistors at the nanometer scale needed for modern AI chips. Without it, no factory on Earth can produce leading-edge processors. Three sole-source suppliers feed it: Zeiss (optics), TRUMPF (laser), and Cymer (light source). Roughly 230 exist on Earth. If ASML goes offline, zero new scanners get built.

This is where wafers, photoresists, and EUV scanners converge. Fabrication etches billions of transistors onto silicon, layer by layer, at dimensions measured in atoms. At the leading edge, only TSMC can do this at scale. The vast majority of chips flow through their foundries in Taiwan.

High Bandwidth Memory (HBM) is the stacked memory bonded directly to the processor, the other half of every AI chip. These facilities need the same ASML scanners and wafers and photoresists as the previous step.

Everything converges back to one island. Fabricated dies and HBM stacks all arrive at TSMC's proprietary CoWoS lines, which bond processor and memory onto a single silicon interposer. Samsung and Intel have competing concepts but none are qualified at volume. One company, one island, sold out through 2026.