Preparation of irregular silica nano-abrasives for the chemical mechanical polishing behaviour on sapphire substrates

Abrasives directly affect the polishing rate and surface quality for sapphire chemical mechanical polishing (CMP). In this work, irregular silica nano-abrasives were synthesised by nickel ion-induced effect combined with growth method in order to simultaneously acquire a high polishing rate and a smooth and flat surface quality on sapphire. The synthesis process of irregular silica nano-abrasives is predicted and analysed by zeta potential. The irregular silica nano-abrasives have a distinguished CMP behaviour for a 22.72% increase in polishing rate and a flat surface quality of sapphire. X-ray photoelectron spectroscopy analysis results have confirmed these solid-phase chemical reactions happen during the sapphire CMP process. In addition, it was analysed about the polishing process and mechanism by establishing a contact model between nano-abrasives and sapphire.