Zirconium and/or cerium-containing mesoporous silica as functional active abrasive particles for radical-facilitated chemical mechanical polishing

Oxidative reactive species (ORS)-facilitated chemical mechanical polishing (CMP) is emerging as a facile and environmentally friendly approach to avoid the overuse of inorganic strong oxidants in conventional CMP slurries. The slurry components play a crucial role in the enhancement of ORS production by advanced oxidation processes, such as photocatalytic and Fenton-related reactions. Nevertheless, the rational design and tunable fabrication of functional active abrasive systems towards ORS-assisted CMP are greatly desired and remain challenging. In this study, zirconium and/or cerium metal species were incorporated into dendritic silica nanospheres (DSNs) skeletons as photochemically and tribochemically active sites using a simple wet-impregnation method. The ORS-facilitated CMP performance of the DSNs−Zr/Ce, DSNs−Zr, DSNs−Ce, and DSNs was evaluated through the ultraviolet irradiation assisted polishing experiments toward silica materials. The CMP slurry was composed of DSNs-based particles, polyvinylpyrrolidone, hydrogen peroxide, pH regulator, and deionized water. Various characterization methods, including X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectrometry, Fourier transform infrared spectroscopy, atomic force microscopy, and nitrogen adsorption−desorption, were utilized in this work. The DSNs−Zr/Ce abrasive systems concurrently offered the lowest surface roughness (1.10 Å of Ra and 1.45 Å of Rq over a measurement area of 5.0 × 5.0 μm2) and the highest removal efficiency (208 nm/min). The porous and flexible structures of the DSNs-involved abrasives might contribute to the friction reduction at the abrasive−substrate interface, thus minimizing surface damage and improving surface quality. The coexistence of the photochemically and tribochemically active sites should be responsible for the enhancement in surface modification and material removal, benefitting from the effective photocatalysis and Fenton-related systems. The results of the photodegradation tests over methylene blue dyes revealed that the photocatalytic activity and ORS production efficiency of the DSNs-based materials followed the order: DSNs−Zr/Ce > DSNs−Zr > DSNs−Ce > DSNs. This research aims to provide a promising strategy for the development of functional active abrasives with better performance in ORS-facilitated polishing. © 2024 Elsevier B.V.