Synthesis, characterization of CeO2@SiO2 nanoparticles and their oxide CMP behavior

SiO2 ultrafine spheres are prepared by sol–gel method using tetraethylorthosilicate and ammonia as raw materials. CeO2-coated SiO2 (CeO2@SiO2) composite nanoparticles are also synthesized through chemical precipitation method. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectrometer (XPS) and dynamic light scattering (DLS) are used to characterize the CeO2@SiO2 composite particles. Silicon wafer covered by thermal oxide film is polished by CeO2@SiO2 composite abrasives, and the polishing behavior of novel composite abrasives is characterized by atomic force microscope (AFM). The results indicate that the phases of the as-prepared CeO2@SiO2 composite particles are composed of cubic fluorite CeO2 and amorphous SiO2. CeO2@SiO2 composite particles have excellent spherical morphologies and uniform particle size of 150–200 nm. The particle size of CeO2 as shell is about 10 nm. After coating, the chemical state of SiO2 is changed due to the formation of Si–O–Ce bond. The root-mean-square (RMS) roughness within 10 × 10 μm2 area of thermal oxide film after polished by CeO2@SiO2 composite abrasives is 0.428 nm, and material removal rate can reach 454.6 nm/min.