APPARATUS AND METHOD FOR INSPECTION OF PHASE SHIFT MASK

摘要

A phase shift mask inspection apparatus according to the present invention comprises a laser light source for outputting laser light in a deep ultraviolet region, optical conversion means for converting the laser light outputted from the laser light source into light of a point source group consisting of a plurality of point sources, an illumination optical system for separating the light of the point source group converted by the optical conversion means into two polarized light beams shifted sideways and illuminating these polarized light beams onto a phase shift mask in which a phase shifter is formed, a sensing optical system for superimposing the two polarized light beams passed through the phase shift mask on one another to produce interference light, and phase value computing means for calculating the phase value at the phase shifter in the phase shift mask on the basis of the intensify of the interference light produced by the sensing optical system.