Preparation of non-spherical silica composite abrasives by lanthanum ion-induced effect and its chemical–mechanical polishing properties on sapphire substrates

Chemical–mechanical polishing is the only technology that can provide a global planarization, and has become widely accepted. Abrasives are one of the important factors influencing chemical–mechanical polishing. In order to improve surface planarization and increase material removal rate of sapphire substrates, non-spherical silica composite abrasives were synthesized by lanthanum ion-induced effect-assisted growth method. Scanning electron microscopy showed the morphologies of non-spherical silica composite abrasives were peanut-shaped, chemical–mechanical polishing tests displayed the material removal rate of the non-spherical silica composite abrasives increased by 32.6% compared with spherical silica composite abrasives, Ambios Xi-100 surface profiler indicated the best surface roughness of sapphire substrate was 1.540 nm, and the element compositions of solids after polishing were analyzed by X-ray photoelectron spectroscopy, which investigated the interactions between abrasives and sapphire substrates. Non-spherical silica composite abrasives may lead to more solid-chemical reactions with sapphire substrates, and higher material removal rate may be also attributed to the mechanical grinding effect enhanced owing to the unique shape to achieve the purpose of material removal.