Study on the interaction between SiO2 and ZrO2 in the chemical mechanical polishing of zirconia ceramic with colloidal silica

Abstract Colloidal silica is usually used for the chemical mechanical polishing of zirconia ceramic wafer in industry, but the process is often optimized only through experience without a precise understanding of the polishing mechanism. There are still many theoretical and technical issues, especially the material removal mechanism and the effect of polishing on the phase transformation, have not been studied in depth. In this study, the effect of the abrasive concentration, polishing pressure and slurry pH on the material removal rate was analyzed. It is found that the removal rate tends to be stable when the concentration exceeds 30 wt%; the influence of pressure on the polishing rate conforms to the Preston formula. When the pH of the slurry is 6, the removal rate is the highest, but polishing under acidic conditions will leave corrosion pits due to the dissolution of the stabilizer. Through X-ray photoelectron spectroscopy analysis of the residue on the wafer surface, it was found that Si-O-Zr bonds were formed, but it was uncertain whether the residue was zirconium silicate. Through X-ray diffraction analysis, it is found that polishing will not affect the crystal structure of zirconia. The Zr-O-Si bond formed by tribochemical action on the ceramic surface prevents the deep migration of surface hydroxyl groups. At the same time, kinetic factors will cause internal hydroxyl groups to transfer to the surface for recovery oxygen vacancies, thereby stabilizing the tetragonal phase.