Combined asperity contact and fluid flow model for chemical-mechanical polishing

This paper presents, for the first time, a physical model of chemical-mechanical polishing (CMP) that combine the effects of polishing pad roughness and slurry hydrodynamic pressure. Recently, the authors introduced a statistical asperity model to analyze contact of wafer and the polishing pad. This model is extended to include slurry flow hydrodynamics. Fluid film thickness between the wafer and pad is first estimated from measured pad roughness. Fluid pressure is then calculated from finite element simulation. The model is used to investigate parametric effects of pressure, platen velocity and pad roughness