Effect of hydrogen peroxide concentration on surface micro- roughness of silicon wafer after final polishing

The effect of hydrogen peroxide (H2O2) concentration in alkaline slurry on the surface micro-roughness of final polished silicon wafer was investigated. The root mean square roughness (RMS) reached minimum with H2O2 when the concentration is 0.05 wt%. Meanwhile, the contact angle of the polished surface was decreased to 21°. This decrease was attributed to enhanced chemical reaction in the CMP process. Electrochemical impedance was measured to explore the variation with addition of H2O2 in the reaction process of silicon erosion. Based on the measurements, a mechanism was suggested to explain the phenomenon in combine with the coefficient of friction force in the chemical mechanical polishing (CMP) process.