METHOD FOR MEASURING FILM THICKNESS DISTRIBUTION

摘要

The present invention is directed to a method for measuring film thickness distribution, comprising calculating a profile P1 indicating wavelength dependence of a reflectance of a first wafer being an object to be measured with respect to a light at wavelengths not less than a wavelength region of visible light; calculating a profile P21 indicating wavelength dependence of a reflectance of a second wafer with respect to a light at wavelengths not less than a wavelength region of visible light, the second wafer having thin films including a second thin film that is t [nm] thinner or thicker than a set film thickness T2 of the second thin film of the first wafer; obtaining a wavelength »1 observed when a profile P31 of a difference between the calculated profiles P1 and P21 becomes zero; and selecting a waveband including the obtained wavelength »1 as a waveband of a light for use in the film thickness distribution measurement by the reflection spectroscopy, wherein the film thickness distribution of the first thin film is measured by the reflection spectroscopy in a manner that a surface of the first wafer is irradiated with a light to selectively measure only reflected light at the selected waveband of reflected light from the surface of the first wafer. The method can precisely measure the film thickness distribution of a wafer with a two layer of thin films at high density in a short time.