Device for illuminating wafers coated with photoresist material. Unlike steppers, scanners scan the entire mask with a beam of light.

Device for illuminating wafers coated with photoresist material. Unlike scanners, steppers illuminate part of the wafer in one step, then move the wafer and/or the photomask and repeat the procedure.

Plane-parallel plates of glass with a highly polished surface. These serve as raw material for making mask blanks. They are coated with a chromium and then a photoresist layer.