Discuss about the term - Photolithography

Photolithography (also known as optical lithography), which is one of the kinds of lithography is a process used in micro fabrication to selectively remove parts of a thin film (or bulk of a substrate). It uses light to transfer a geometric pattern from a photo mask to a light-sensitive chemical (photo resist, or simply "resist") on the substrate. A series of chemical treatments then engraves exposure pattern into material underneath the photo resist. In a complex integrated circuit (for instance, modern CMOS), a wafer would go through photolithographic cycle up to 50 times.