Tailored Shell Engineering of γ-Fe2O3@SiO2 Nanoparticles for High-Performance and Recyclable Chemical Mechanical Planarization

As semiconductor devices continue to scale down and integrate more densely, the atomic-level planarization of metal interconnects and dielectric layers is critical. Consequently, the development of chemical mechanical planarization (CMP) materials must address both high polishing performance and environmental sustainability. In this study, γ-Fe2O3@SiO2 core–shell abrasive particles were designed to overcome the performance and recyclability limitations of conventional SiO2 abrasives. The γ-Fe2O3 core enables an efficient magnetic separation from spent slurry, while the tunable SiO2 shell enhances the dispersion stability and modulates the polishing characteristics. When applied to the CMP of tungsten (W) thin films, the optimized γ-Fe2O3@SiO2 abrasives achieved a higher removal rate and lower surface roughness than commercial SiO2-based slurries. Notably, the abrasives maintained a high performance even after 10 reuse cycles through simple magnetic recovery. This demonstrates a highly efficient and sustainable design strategy for next-generation CMP materials.