Heterojunction-Enhanced CeO ₂ -Based Core–Shell Abrasives for High-Efficiency Photoassisted Chemical Mechanical Polishing

Chemical mechanical polishing (CMP) traditionally relies on a synergistic interplay between mechanical abrasion and chemical etching, yet the limited chemical activity of conventional abrasives often restricts efficiency. Herein, a photoassisted in situ Ce³⁺ enrichment strategy is established and applied in a core-shell abrasive with Ce-doped SnO₂ (CTO) as core and La-doped CeO₂ (LCO) as shell (CTO@LCO). A type-II heterojunction at the core-shell interface facilitates efficient photogenerated electron transfer from CTO to LCO, highly promoting the chemical activity of the LCO shell. Combined with the robust mechanical action of faceted CTO core, the CTO@LCO abrasive exhibits remarkable material removal rate (MRR) of 608 nm/min for TFT-LCD glass and 315 nm/min for Si wafer, and simultaneously reduced surface roughness (Ra) of 0.277 and 0.190 nm, respectively, outperforming commercial CeO₂ abrasives by 129.56% (137.84%) in MRR and 45.02% (61.83%) in Ra. Comprehensive experimental characterizations and first-principles calculations shed light on the mechanism of doping-induced band structure regulation and heterointerface design in such photoassisted chemical mechanical polishing (PACMP). This work opens a way to in situ chemically activate abrasives for high-performance CMP toward advanced ultraprecision manufacturing.