Tribological analysis on powder slurry in chemical mechanical polishing

Chemical mechanical polishing (CMP) is a key technique for wafer global planarization. Many studies have been conducted in recent years to analyse the slurry flow between a pad and a wafer due to its importance in CMP processing. In these studies, however, the grains in the slurry were not considered. Thus this investigation uses a grain flow model to analyse the slurry flow between wafer and pad. The proposed model predicts the film thickness of the slurry flow with various convex wafer curvature radius under a variety of the CMP parameters including load, rotation speed and grain size. The theoretical results compare well with experimental data in the literature. This study elucidates grain flow during CMP processing and further contributes to understanding of the CMP mechanism.