Analyses and experimental confirmation of removal performance of silicon oxide film in the chemical–mechanical polishing (CMP) process with pattern geometry of concentric groove pads

Abstract

A Reynolds equation that considers both the smoothing hydrodynamic pressure and the pattern of surface topography at the polishing pads was used to solve the distribution of the hydrodynamic field. A three-body abrasion wear model for solving the removed thickness of silicon oxide films was also introduced to obtain the removal rate of SiO2 film in a chemical–mechanical polishing (CMP) process. The suction hydrodynamic pressure field expands its region with increasing groove width and decreasing depth of grooves. The flow rate of the slurry was thus increased, and the removal rate also increased with an increased number of abrasive particles. The solid contact pressure was much higher than the hydrodynamic pressure. The three-body abrasion for the wear depth of a particle arises from the solid contacting pressure and is hence more important than the hydrodynamic pressure. The removal rate of the SiO2 film was dominated by the number of abrasive particles, which was affected by the variation of the hydrodynamic pressure in addition to the wear depth controlled by the solid contact pressure. The thickness of the silicon oxide films removed increased with decreasing grooving width and depth.