High Removal Rates and Atomically Smooth Surfaces Are Achieved on Silicon Wafers Using the New SiO₂@ZrO₂ Core-Shell...

The relentless miniaturization of integrated circuits demands chemical mechanical polishing (CMP) technologies that achieve both high material removal rates (MRR) and atomic-scale surface quality. Herein, we synthesize sub-100 nm SiO₂@ZrO₂ core-shell composite abrasives (amorphous SiO₂ core ~70 nm, tetragonal ZrO₂ shell ~6 nm) via a facile sol-gel method. Electron microscopy and X-ray photoelectron spectroscopy strongly indicated uniform core-shell architecture and Si-O-Zr covalent bonding essential for stable coating. Polishing tests show that the abrasives deliver an MRR of 353.54 nm/min-approximately 2.8 times that of pure SiO₂-and reduce surface roughness to Ra = 0.105 ± 0.015 nm, approaching atomic-scale planarization. The superior performance stems from the rigid ZrO₂ shell, which suppresses elastic deformation and preserves spherical contact morphology. This mechanical effect simultaneously increases shear stress by reducing contact area and minimizes scratches by limiting indentation depth. Overall, this work offers a simple, controllable strategy for designing high-efficiency CMP abrasives and demonstrates the considerable potential of SiO₂@ZrO₂ core-shell materials for damage-free, atomic-scale surface finishing.