Micro-scratch inspection system for semiconductor process by two-ways laser scattering method

CMP (Chemical Mechanical Polishing) is a key technology in semiconductor processing. However, when a problem arises in the polishing conditions, scratches are caused and yield can deteriorate drastically. We study the characteristic figure of scratch the depth of which is extremely shallow compared with width. We propose a 2-way illumination comparative discrimination method. By experiment, we obtain a good discrimination ratio between scratch and particle on unpatterned dummy wafers.