Activity‐Tunable Ultrasmall Ceria Abrasive for Ultra‐Precision Chemical Mechanical Polishing of Semiconductor Dielectric Layers

Abstract In the pursuit of Moore's Law, the transition to integrated circuits (ICs) and atomic‐scale device fabrication places pressure on chemical mechanical polishing (CMP) to deliver flawless surfaces. Moving beyond conventional abrasives, ultra‐small and monodisperse ceria nanoparticles have arisen as a critical materials platform. Tailoring their size, composition, and surface properties is important to simultaneously achieving high polishing selectivity and sub‐angstrom smoothness. However, CeO 2 abrasives with ultra‐small particle sizes are plagued by challenges in production, colloidal instability leading to agglomeration, and relatively low polishing rates. Herein, we report a universal doping‐mediated activity adjusting platform and successfully develop ultrasmall CeO 2 mesoporous nanoabrasive. USM‐Ce, with sizes under 30 nm, exhibits uniform morphology and excellent dispersibility. Theoretical calculations combined with various characterization reveal that the constructed doping regulation platform effectively reduces the formation energy of oxygen vacancies in USM‐Ce, thereby markedly increasing the concentration of both oxygen vacancies and Ce 3+ ions. Notably, USM‐Ce can further enhance the material removal rate to 232% of the original through doping regulation. Meanwhile, the proposed ultrasmall abrasives deliver an atomically planarized, nearly scratch‐free surface with an angstrom‐level finish. The newly developed mesoporous CeO 2 nanoparticles offer a versatile platform for ultrasmall ceria‐based nanoabrasives in critical advanced IC manufacturing processes.