FILM THICKNESS MEASUREMENT DEVICE, FILM THICKNESS MEASUREMENT METHOD, AND POLISHING DEVICE EQUIPPED WITH FILM THICKNESS MEASUREMENT DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a film thickness measurement device and a film thickness measurement method which can improve an accuracy of measurement of a film thickness.SOLUTION: A film thickness measurement device comprises: a substrate stage 87 for horizontally supporting a substrate W; a rinse water feed section 90 for feeding rinse water onto the entire surface of the substrate W on the substrate stage 87; a film thickness measurement head 84 which radiates light onto a measurement area on the surface of the substrate W on the substrate stage 87, creates spectrum of light reflected from the measurement area, and determines a film thickness of the substrate W on the basis of said spectrum; and a gas injection part 130 which forms a jet stream of a gas on an optical path of light and applies said jet stream of the gas onto the measurement area.