What it means
Photoresist is a light-sensitive polymer that fabs spin onto a wafer before lithography. When the lithography tool projects a circuit pattern, the exposed resist changes chemically, and a developer step then washes away either the exposed or unexposed regions — leaving a stencil that guides etching and deposition. Every patterning step consumes fresh resist, so a fab burns through it continuously, and each lithography generation (DUV, EUV) needs its own precisely engineered chemistry. Making resist at the required purity is extraordinarily demanding, and supply is concentrated among a few, mostly Japanese, specialty-chemical makers. That concentration makes photoresist a quiet but critical constraint in the AI supply chain: without it no wafer can be patterned, and a disruption at one plant can ripple across the whole industry.
Why it matters to investors
Photoresist supply is dominated by a handful of specialty-chemical firms, giving them pricing power and making them a single point of failure the market watches closely. For the AI trade, resist availability is an upstream input that every foundry — and therefore every accelerator — depends on.
Companies on this part of the chain
Named to show where the term sits in the AI supply chain — research, not advice, and never a recommendation to buy or sell.
Related terms
See Photoresist in the live AI chain.
THE ENTITY maps every constraint onto one live model — which part is tight now, who owns it, and who gets squeezed when it moves. Plain-English reads you can check.
THE ENTITY is an educational read on the AI supply chain — research, not investment advice. It explains how the chain works and who sits where, never price targets or buy/sell calls.