METHOD AND DEVICE FOR MEASURING OPTICAL THIN FILM, AND DEVICE FOR REMOVING INTERFERING LIGHT IN OPTICAL THIN FILM MEASUREMENT USED FOR SAME DEVICE

摘要

PROBLEM TO BE SOLVED: To measure the physical amount of a thin film formed on the surface of a transparent base material, by preventing reflected light from the back surface of the transparent base material from being superimposed on measuring light without any complicated operation. ;SOLUTION: In an optical thin film measuring method, the surface of a sample 10 in which a thin film 12 is formed on the surface of a transparent substrate 11 is irradiated with a light beam, and reflected light from an irradiation point is detected to measure the physical amount of the thin film 12. A liquid 26 with the approximately same refractive index as that of the substrate 11 is housed in a container to bring the back surface of the substrate 11 into contact with the liquid 26, and light transmitted through the sample 10 and incident into the liquid 26 is absorbed to a light absorbing body 24. In another constitution, a knife edge plate is arranged in the vicinity of the sample without shielding reflected light from the irradiation point so as to shield the light beam reflected at the back surface of the substrate and transmitted through the thin film, and the knife edge of the knife edge plate is located on the side of the reflected light with respect to the irradiation point.;COPYRIGHT: (C)1999,JPO