Photolithography

Photolithography is a multi-step lithography process in which user-defined patterns are transferred to substrates with the help of ultraviolet light and a pattern-carrying mask. In this process, the substrate is first thoroughly cleaned by wet chemical treatments to render the surface free of organic and inorganic impurities. The substrate is then coated with a layer of photoresist by spin coating after exposing the substrate to a chemical (e.g., hexamethyldisilazane) that improves adhesion between the photoresist and the substrate.