Study on evaluation method for surface topography of polishing pad based on optical Fourier transform

We suggest that evaluation method of the polishing pad surface topography by optical technique based on optical Fourier transform. In our measurement system, intensity distribution of the diffraction light detected by the area CCD camera reflect the surface topography of the polishing pad. In this case, the incident light angles is a dominant parameter to detect the diffraction light from the several surface topographies formed by dressing process. The wavelength composition ratio (WCR)s were calculated by integration of the diffraction light intensity against the spatial wavelength of the polishing pad surface topography to quantify the surface topographies parameter of the polishing pad. As results, the high correlation coefficient between the WCRs and the material removal rate and erosion can be realized over 0.8 by optimizing incident light angle.