Role of dopant valence on CeO2 abrasives performance in SiO2 chemical mechanical polishing

A mechanistic framework distinguishes strain-driven and charge-compensation pathways in CeO 2 abrasives. • Interfacial electron delocalization weakens subsurface Si-O bonds in CeO 2 /SiO 2 systems. • Optimized Co-doped CeO 2 abrasives achieve higher MRR and excellent surface quality. Atomic-scale manufacturing requires precise material removal at the nanometer level, where chemical mechanical polishing (CMP) serves as a critical process for global planarization in integrated circuit fabrication. CeO 2 abrasives are widely used in CMP due to their chemical affinity for SiO 2 , yet the limited active Ce 3+ sites in pure CeO 2 constrain the material removal rate ( MRR ). Herein, a comparative study of isovalent Zr-doped and aliovalent Co-doped CeO 2 abrasives is reported to deconvolute the distinct roles of lattice strain and charge compensation at the atomic scale. Co doping drives the oxygen vacancy formation energy to −0.81 eV, enabling energetically favorable defect generation, whereas Zr 4+ doping only reduces it to 2.10 eV via lattice contraction. This fundamental difference yields substantially higher Ce 3+ and oxygen vacancy concentrations in Co-doped abrasives. Consequently, the MRR follows a volcano-shaped trend with dopant content for both systems, reaching 388 nm·min −1 (1.74 times that of pure CeO 2 ) for the optimal Co-doped abrasive and 327 nm·min −1 (1.47 times) for the Zr-doped counterpart. All doped abrasives also eliminate localized surface defects, achieving near-atomic smoothness with Ra of 0.146–0.187 nm. Density functional theory reveals that Co doping establishes a delocalized electron transfer network via Co 3d orbital hybridization at the CeO 2 /SiO 2 interface, concurrently strengthening interfacial adhesion (0.1612 eV·Å −2 ), intensifying polarization, and elongating subsurface Si O bonds to 1.767 Å, thereby predisposing these bonds to rupture under mechanical shear. These atomic-scale insights establish a mechanistic framework that quantitatively differentiates the physical and chemical pathways of isovalent versus aliovalent doping, providing a rational basis for designing high-performance CeO 2 -based abrasives toward atomic-scale manufacturing. Download: Download high-res image (201KB) Download: Download full-size image