Photolithography is a technique where a photosensitive film (resist) is exposed through a mask. The mask, e.g. is a quartz substrate coated with a structured chromium layer. The resolution of the contact exposure used here is 2 µm.
The sample is coated with a liquid resist. Spin coating generates a thin, homogenous film. The Gyrset (closed bowl spinning) keeps the sample in a saturated solvent atmosphere. This reduces the so called edge bead and allows for a more homogenous coating of irregular pieces.