Fab desk

The wafer: the most precisely made commodity in industry

Published 3 August 2026. Facts verified to 27 July 2026 unless dated otherwise.

Before any chip is printed, someone has to grow a nearly perfect cylinder of single-crystal silicon and slice it into mirrors. That industry is small, concentrated and almost never discussed.

From sand to electronic-grade polysilicon

Silicon is abundant; electronic-grade silicon is not. Metallurgical silicon is refined through chemical processes into polysilicon of extraordinary purity, with impurities measured at levels that make most industrial purity specifications look casual. This step is energy-intensive and capital-intensive, and it is dominated globally by a handful of producers.

Growing a single crystal

Polysilicon is melted and a seed crystal is slowly withdrawn from the melt while rotating, pulling a cylindrical ingot that shares the seed's crystal orientation throughout. Dopants can be added to the melt to set the wafer's baseline electrical properties. The process is slow, thermally delicate and unforgiving: the goal is a crystal with almost no dislocations, of consistent diameter, over a metre or more of length.

Slicing, lapping, polishing

The ingot is ground to precise diameter, then sliced into wafers with wire saws. Each wafer is then lapped, etched and chemically-mechanically polished until one face is flat and smooth at a level where the relevant measurements are of nanometre-scale variation across a 300mm disc. Edges are profiled to resist chipping. Some wafers then receive an epitaxial layer, a fresh crystalline film grown on the surface, when the device requires an even more perfect starting layer than the bulk crystal provides.

Why 300mm, and why it matters to fab economics

Larger wafers carry more chips per processing cycle, and since many process costs scale with the wafer rather than the chip, bigger wafers mean lower cost per chip. The industry standardised on 300mm for high-volume manufacturing decades ago, and the next size increase has repeatedly failed to justify its enormous retooling cost. A commercial fab today is therefore a 300mm fab, which is why the phrase carries weight in describing the plant being built at Dholera DURABLE.

The strategic point

Wafer manufacturing is a separate industry from chip manufacturing, and it is geographically concentrated in a small number of producers. A country that builds fabs still imports wafers unless it also builds that upstream capability, which is a longer and quieter industrial project. It belongs on the honest ledger of what a first fab does and does not achieve, a distinction our strategic case page keeps carefully.