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

An optical technique based on the optical Fourier transform has been developed to evaluate the characteristics of polishing pad surface topography. The power spectrum from the optical Fourier transform, which correlates with the diffracted light intensity distribution from the diffused reflection laser light of the polishing pad surface, is observed by an area sensor camera. Then, the correlation between the spatial frequency characteristic of the polishing pad topographies and the material removal rate are investigated.