Pure-play semiconductor foundries are producing wafers as a service for other companies: fabless semiconductor companies, integrated device manufacturers (IDMs), and sometimes product companies such as Apple that is making its own chips. TSMC is the largest pure-play foundry.

Wafers produced by a semiconductor foundry come in a pre-defined size. The major wafer sizes today are 300mm and 200mm. This paper explains the economy of scale related to wafer size, and the image below shows the various wafer size available in the market today.