Abstract

The laser scanning inspection system (LSIS) is a large-area high-speed surface inspection system based on laser scanning and light scattering. It currently inspects patterned and unpatterned photolithography masks for particulates, down to 2 μm in size. Masks up to 6 × 6 in. can be inspected in <60 s. The LSIS is controlled by an AT&T PC6300. Light scattering for inspection of smooth surfaces is a well-established technique. For patterned surfaces light is scattered from the pattern and the defects. There may also be diffraction from the pattern.

© 1987 Optical Society of America