Preparation, characterization and oxide CMP performance of composite polystyrene-core ceria-shell abrasives

To improve their chemical mechanical polishing (CMP) performance, composite polystyrene-core ceria-shell (PS/CeO2) abrasives were synthesized by in-situ chemical precipitation. The as-synthesized PS/CeO2 composite microspheres samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA) and zeta potential analysis. Oxide CMP performance of the PS/CeO2 composite abrasives was investigated by atomic force microscopy (AFM). The results indicate that PS/CeO2 composite abrasives with a core–shell structure are obtained successfully. The particle size of as-prepared PS/CeO2 composite particles is about 140 nm, and the PS microspheres are uniformly coated by CeO2 nanoparticles. The surface of thermal oxide film polished by PS/CeO2 composite abrasives has lower topographical variations and surface roughness than that polished by CeO2 nanoparticles. After polished by composite abrasives, root-mean-square roughness of wafer within 5 μm × 5 μm area is 0.331 nm, and material removal rate can reach 484.5 nm/min.