Study of abrasive-particle size dependence of polishing rate based on a simple mechanical model

The relationship between abrasive particle size and polishing rate (PR) of a chemical mechanical polishing (CMP) process is studied both experimentally and theoretically. PR of NiP-plated aluminum substrates polished by spherical silica particles of a uniform size becomes the maximum around at 50nm in particle size. A simple mechanical model for CMP is proposed to describe this behavior. It is also shown experimentally that mixing silica particles of different sizes can enhance PR.