Preparation of La-doped colloidal SiO2 composite abrasives and their chemical mechanical polishing behavior on sapphire substrates

• DOI: 10.1016/j.precisioneng.2015.10.009
• Publication Date: 2015-11-20T23:50:51Z
• Authors: Hong Lei; Kaiyu Tong
• Keywords: 0103 physical sciences; 02 engineering and technology; 0210 nano-technology; 01 natural sciences

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 removal rate and improve surface quality of sapphire substrate, a series of novel La-doped colloidal SiO 2 composite abrasives were prepared by seed-induced growth method. The CMP performance of the La-doped colloidal SiO 2 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 La-doped colloidal SiO 2 composite abrasives achieve lower surface roughness, higher material removal rate than that of pure colloidal SiO 2 abrasive under the same testing conditions. Furthermore, the acting mechanism of the La-doped colloidal silica in sapphire CMP was investigated. X-ray photoelectron spectroscopy analysis shows that solid-state chemical reactions between La-doped colloidal SiO 2 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.