Preparation, characterization, and application of dendritic silica-supported samarium-doped ceria nanoparticles in ultra-precision polishing for silica films

The aim of the present study is to investigate the structure optimization of ceria-based composite particle abrasives for improved chemical mechanical polishing (CMP) performance. The core/shell-structured composite particles, comprising dendritic-like mesoporous silica (D-mSiO2) internal cores and grafted Ce1 − xSmxO2 (x = 0, 0.2) solid solutions, were prepared via a facile aqueous solution-based co-precipitation approach. The morphologies, chemical compositions, and crystalline structures of the as-formed samples were characterized by powder X-ray diffraction, high-resolution transmission electron microscopy, field-emission scanning electron microscopy, X-ray photoelectron spectroscopy, scanning transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The silicon oxide wafers before and after CMP were examined in terms of atomic force microscopy and 3D noncontact interferometric microscopy for the information on surface quality and roughness, sectional profile, and material removal rate. The developed ceria-based abrasives presented significantly improved polishing performance toward silica by comparison with commercial ceria abrasives. The D-mSiO2 cores were expected to reduce surface roughness and eliminate surface scratch, and the samarium doping into the coated ceria nanoparticles contributed to the improvement of removal efficiency. The present results provide a facile strategy toward the design and synthesis of novel ceria-based abrasives with potential applications in achieving high-efficiency and damage-free finishing.