= Photolithography
<Photolithography> transfers a pattern defined by <light> into a photosensitive <photoresist> coating. After exposure and development, the remaining <photoresist> forms a relief pattern that can protect selected regions during <etching> or another material-transfer step.<Glossary of Lithography Terms by Chris A. Mack>[Entries Photoresist, Patterning and Photolithography]{ref}
A <photomask> can place bright and dark regions in the projected <optical image>. A <positive photoresist> develops more rapidly where exposed, so sufficiently exposed regions are removed; a <negative photoresist> retains the exposed regions instead. The final geometry depends jointly on the <optical image> and the material response. In particular, <diffraction> limits the image delivered by the optics, while <photoresist contrast> determines how a gradual variation of exposure is converted into a material boundary. <Photolithography> therefore connects <wave optics>, <photochemistry> and <semiconductor device fabrication>.
Back to article page
