Patent ID: 7230720

Claim:
A system comprising: a film thickness measuring apparatus for measuring a film thickness of a member to be processed, including: a differential waveform pattern data base for holding a standard pattern consisting of a time differential value of an interference light for each of multiple wavelengths with respect to a film thickness of a first member to be processed; a unit for measuring an intensity of an interference light for each of multiple wavelengths of a second member to be processed; a unit for obtaining a real pattern consisting of time differential values of measured interference light intensities; and a unit for obtaining a range of a film thickness of the film by using a pattern of zero-cross points of the differential values of intensities of the received interference light for a first wavelength among the received interference lights of the multiple wavelengths; and a unit for determining a processed amount of the film within the obtained thickness range of the film by using a pattern of zero-cross points of the differential values of intensities of the received interference light for a second wavelength among the received interference lights of the multiple wavelengths.