Recovery and Reuse of Magnetic Silica-Coated Iron Oxide Particles for Eco-Friendly Chemical Mechanical Planarization

Chemical mechanical planarization (CMP), a crucial process in semiconductor manufacturing, raises environmental concerns due to increased waste generation, prompting questions about its long-term sustainability. To address this issue, we explore an innovative approach to the waste management and recycling process by introducing magnetite (Fe3O4) particles coated with SiO2 layers, aimed at enhancing the CMP recycling efficiency. These core-shell particles exhibit controlled shell thickness, and modified surface charges, as confirmed by various analytical techniques. Our results reveal that slurries containing Fe3O4@SiO2 particles significantly improve W removal rates and surface smoothness compared to conventional slurries, attributed to the optimal mechanical properties. Moreover, the magnetite core facilitates the magnetic separation and recovery of used particles from spent slurries, offering a cost-effective and environmentally friendly solution. The recycling efficacy of these particles is demonstrated through multiple CMP cycles, showing consistent removal rates and surface quality, highlighting the potential of magnetic separation in sustainable CMP.