Preparation of Ni-Doped Colloidal Silica Abrasives and Their Chemical Mechanical Polishing Performances on Sapphire

Abstract

Chemical mechanical polishing (CMP) has become a widely accepted global planarization technology. Abrasive is one of the key elements in CMP process. In order to enhance material removal rate (MRR) and improve surface quality of sapphire substrate, a series of novel Ni-doped colloidal silica abrasives were prepared by seed-induced growth method. The CMP performances of composite abrasives on sapphire substrate were investigated using UNIPOL-1502 polishing equipment. The analyses on the surface of polished sapphire substrate indicate that slurries containing the Ni-doped colloidal silica composite abrasives achieve lower surface roughness and higher material removal rate than that of pure colloidal SiO2 abrasive under the same experimental conditions. Furthermore, the acting mechanism of the Ni-doped colloidal silica abrasive on sapphire CMP was investigated. X-ray photoelectron spectroscopy analysis shows that solid-state chemical reactions between Ni-doped colloidal silica abrasive and sapphire surface occur during CMP process, which can promote the chemical effect in CMP and lead to the improvement of material removal rate.