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Friday, October 8, 2021

CONTINUITY: How Photolithography Works—Part 3: Photoresist

Photoresist is the “secret sauce” of microelectronics. It is a chemical coating which, applied to a silicon wafer, is rendered soluble or insoluble by exposure to light. Post-exposure, the soluble part is washed away, leaving a mask which protects portions of the chip not to be affected by the next processing step. This sounds simple, but achieving nanometre resolution and avoiding optical distortion are formidable challenges which have been surmounted as device geometries shrink.

Posted at October 8, 2021 13:06