Novel polystyrene/CeO_2-TiO_2 multicomponent core/shell abrasives for high-efficiency and high-quality photocatalytic-assisted chemical mechanical polishing of reaction-bonded silicon carbide

摘要

Novel polystyrene (PS)/CeO2-TiO2 multicomponent core/shell abrasives were developed and exploited for high-efficiency and high-quality photocatalytic-assisted chemical mechanical polishing (PCMP) of the reaction-bonded silicon carbide (RB-SiC). Firstly, we proposed a modified process to synthesize the novel core/shell abrasives, which possessed a particular yielding effect and an enhanced photocatalytic activity. The as-synthesized abrasives were then characterized by FESEM and XRD, which showed that the CeO2-TiO2 shells were coated on the PS cores successfully, with the average particle size of ca. 200 nm (shell: 20 nm, core: 160 nm). PCMP experiments of RB-SiC were then conduct by exploiting deionized water contained 2.0 wt% CeO2, CeO2-TiO2, PS/CeO2, and PS/CeO2-TiO2 abrasives, respectively. Surface roughness values of RB-SiC before and after PCMP were measured by AFM, which showed that the core/shell based abrasives had the potential to obtain a better polishing quality compared with conventional abrasives. Material removal rates (MRRs) with CeO2-TiO2 based abrasives were higher than those of CeO2 based abrasives under ultraviolet (UV) irradiation. The best polishing performance (R-a: 0.497 nm, MRR: 1.223 mu m/h) was obtained with PS/CeO2-TiO2 abrasives under UV irradiation. Detailed action mechanisms for obtaining the better polishing quality and higher MRR were explained by the particular yielding effect of core/shell based abrasives and the enhanced photocatalytic activity of CeO2-TiO2 based abrasives, respectively.