Simple and facile synthesis of single-crystal CeO₂ abrasives and its highly efficient removal mechanism on SiO₂ film

CeO2 nanoparticles are one of the key abrasives for chemical mechanical polishing (CMP) in advanced integrated circuits. However, synthesizing highly chemically reactive CeO2 often involves ion doping, high-temperature calcination or reduction, which increase cleaning challenges and risk scratching wafers. We developed a simple and facile method for synthesizing single-crystal CeO2. It exhibits superior polishing performance compared to commercial CeO2, with the material removal rate (MRR) increasing to 4141.45 from 3649.99 angstrom/min and the surface roughness (Sa) decreasing to 0.533 from 0.647 nm. The CeO2 abrasives were characterized by X-ray Diffraction (XRD), advanced microscopy techniques (SEM, TEM), X-ray Photoelectron Spectroscopy (XPS), and Hydrogen Temperature-Programmed Reduction (H-2-TPR). It revealed that the synthesized CeO2 has a particle size of approximately 60 nm and its surface was covered with a uniform amorphous layer of similar to 1 nm. XPS and H-2-TPR revealed its high Ce3+ concentration and enhanced oxygen exchange capability. The polishing mechanism was investigated by XPS and High-Resolution TEM (HR-TEM). Under pressure, the CeO2 established Ce-O-Si bonds with the SiO2 surface. Ce3+ provided electrons to the antibonding orbitals of Si-O bonds, effectively breaking stable Si-O bonds and removed SiO2 film in the form of lump SiO2 through mechanical action.