The Chemical Mechanical polishing (CMP) process is now widely employed in the Integrated Circuit Fabrication. However, due to the complexity of process parameters on the material removal rate (MRR), mechanism of material removal and pattern effect are not well understood. In this paper, three contact regimes between the wafer surface and the polishing pad were proposed: direct contact, mixed or partial contact, and hydroplaning. The interfacial friction force has been employed to characterize these contact conditions. Several polishing models are reviewed with emphasis on the mechanical aspects of CMP. Experiments have been conducted to verify the mechanical polishing models and to identify the dominant mechanism of material removal under typical CMP conditions.Singapore-MIT Alliance (SMA)