Preparation of spherical ceria coated silica nanoparticle abrasives for CMP application

Abstract This paper describes synthesis of spherical and highly mono-dispersed ceria coated silica nanoparticles of size ∼70–80 nm for application as abrasive particles in Chemical Mechanical Planarization (CMP) process. Core silica nanoparticles were initially synthesized using micro-emulsion method. Ceria coating on these ultrafine and spherical silica nanoparticles was achieved using controlled chemical precipitation method. Study of various parameters influencing the formation of ceria coated silica nanoparticles of size less than 100 nm has been undertaken and reported. Ceria coating over silica nanoparticles was varied by controlling the reaction temperature, pH and precursor concentrations. Characterization studies using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Energy Dispersive X-ray analysis show formation of crystalline CeO 2 coating of ∼10 nm thickness over silica with spherical morphology and particle size 2 :SiN selective removal rates up to 12 was observed using 1 wt% ceria coated silica nanoparticles slurry.