In computing, lithography is the process of imprinting patterns onto semiconductors to use in circuits.
Photolithography is used to transfer a pattern from a photomask to the surface of a substrate.
The first stage is the imposition of a structure on the beam of light, which is passed through a mask and projected onto the silicon wafer.
The ‘resist’, which is a coating on the wafer, undergoes chemical changes when exposed to light. The solubility of the material is modified and formed into a stencil through the application of a solvent.
What’s the next stage?
The substrate is then exposed to chemicals which produce a solid material which condenses on its surface.
Finally, the etching takes place, which chemically removes layers from the surface of the substrate, leaving only the wanted pattern.
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More generally, lithography is a term for printing onto a flat surface by coating it in a substance that repels ink except for where the pattern is supposed to be.
The word comes from the Ancient Greek words for ‘stone’ and ‘writing’.
