Optical lithography is a process used in semiconductor manufacturing to create intricate patterns on silicon wafers. It involves shining light through a mask that contains the desired pattern, which is then projected onto a photosensitive material called photoresist. The areas exposed to light undergo a chemical change, allowing for selective removal of the photoresist to reveal the underlying silicon. This technique is crucial for producing microchips and integrated circuits, as it enables the precise fabrication of tiny features essential for electronic devices. Optical lithography has evolved over the years, with advancements like deep ultraviolet (DUV) and extreme ultraviolet (EUV) lithography improving resolution and patterning capabilities.