Patent ID: 8065031

Claim:
A polishing end point detection method utilizing torque change in which a wafer having a predetermined film having minute irregularities on the surface is retained by a polishing head, the predetermined film is pressed against and polished by a polishing pad provided on a surface of a rotating platen while rotating the polishing head, and data representing torque of the polishing changed along with progress of the polishing is monitored so as to detect a polishing end point of the predetermined film, the polishing end point detection method including: a first process of measuring a torque creating measured data; a second process of analyzing a periodic component in the measured data by subjecting Fourier transformation to the measured data; a third process of calculating a moving average processing time for removing a varied periodic noise component based on the periodic component; a fourth process of correcting a waveform creating a corrected waveform by performing an averaging process based on the moving average processing time, with the averaging process being calculated continuously during polishing in real time for the measured data; and a fifth process of detecting a polishing end point of the predetermined film based on change in the corrected waveform detected by differentiation of the corrected waveform, whereby both fixed and varied periodic components are analyzed and the change in the corrected waveform is determined by differentiation in detecting the polishing end point.