Patent ID: 9604337
Date: 2017-03-28
CPC Classifications: B24B,H01L

Claim:
1. A method of polishing a substrate having a film, the method comprising: polishing the substrate by pressing the substrate against a polishing tool on a rotating polishing table; irradiating the substrate with light when polishing the substrate; receiving the light reflected from the substrate; measuring intensity of the reflected light at respective wavelength, the reflected light having wavelengths of not more than 1100 nm; calculating relative reflectance by dividing the measured intensity of the light by predetermined reference intensity; producing spectral waveform representing relationship between the relative reflectance and wavelength of the light; performing a Fourier transform process on the spectral waveform to determine a thickness of the film and a corresponding strength of frequency component; and determining a polishing end point of the substrate based on a point in time at which the determined thickness of the film has reached a predetermined target value.