Spin coaters deposit a very thin layer of liquid or resin coatings, often a photoresist, onto the surface of the spinning part, typically a silicon wafer or thin substrate. All spin coaters consist of a metering device (such as a dispenser or nozzle), an apparatus to rotate the part to be coated, and a bowl/lid to contain the excess coating spun off the part. Spin coaters may be powered by an electric motor or other means and often feature variable rotational speeds to help control the coating thickness. In addition to paints and other coatings, spin coaters can also be used to dispense cleaning solutions or etchants in order to prepare a part surface for further coating.
A typical spin coating process. Image credit: Fraunhofer
While spin coaters can be used to coat a variety of different parts in different applications, they are frequently used to coat wafers and other parts integral to semiconductor manufacturing. They are available in a variety of form factors, from tabletop models (shown below) to large booths.
A typical spin coater. Image credit: SPI