What is photolithography?

Photolithography (also called optical lithography or UV lithography) is a process used in microfabrication to pattern parts on a thin film or the bulk of a substrate. It uses light to transfer a geometric pattern from a photomask to a light-sensitive (photoresist) on the substrate. The photoresist is selectively removed by chemical etching, exposing the desired pattern on the underlying material. It is a key technology for manufacturing integrated circuits (microchips), microelectromechanical systems (MEMS), and other micro- and nano-scale devices.