Investigation of Abrasive Removal Depth of Sapphire Wafer for Different Slurry Volume Concentrations of Chemical Mechanical Polishing with Cross Pattern Polishing Pad

In this article, it establishes a new theoretical model of abrasive removal depth of sapphire wafer with different slurry volume concentrations during chemical mechanical polishing by polishing pad with cross pattern. The theoretical model uses binary image pixel division to divide wafer and polishing pad to be small pixels, then the polishing times of wafer polished by polishing pad is calculated. An abrasive contact model for single pixel multiple abrasive particles, to estimate the contact force between single abrasive particle and wafer is then established. When the contact force is calculated, it is possible to calculate the abrasive depth of a single abrasive particle on the surface of the sapphire wafer. Using this theoretical model, it carries out a numerical simulation with an abrasive particle of the same diameter, but with different slurry volume concentrations, the simulation results include not only the average abrasive removal depth at each pixel position, but also the surface condition of wafer. The simulation result is also compared with experimental data, in order to verify that the new model is feasible.