Influence of low concentration CeO2/SiO2 composite abrasive on the CMP performance of silicon wafers
In order to improve the removal rate and maintain good surface quality during chemical mechanical planarization(CMP)of silicon substrate,CeO2 coated SiO2 shell-core composite abrasive was selected and its effect on the removal rate and surface quality of silicon substrate at low concentration was investigated.The chemical composition and morphology of CeO2/SiO2 composite abrasive samples were characterized by scanning electron microscopy(SEM)and X-ray photoelectron spectroscopy(XPS),and a completely coated shell-core structure was confirmed.The BET specific surface area and friction coefficient tests showed that the CeO2/SiO2 composite abrasive has a larger specific surface area and friction coefficient than the SiO2 abrasive under similar particle size,thus the chemical reaction and mechanical grinding of silicon wafers surface were improved.The results show that when the mass fraction of 0.5％CeO2/SiO2 composite abrasive(particle size 75 nm)is used to polish the silicon substrate,the removal rate can reach 530 nm/min.The surface quality of wafer after polishing was characterized by AFM,and the surface roughness of silicon substrate is 0.361 nm.Therefore,compared with traditional SiO2 abrasives,CeO2/SiO2 composite abrasives can provide high removal rate and good surface quality at the same time under low concentration.
chemical mechanical polishing(CMP)CeO2/SiO2 composite abrasivesiliconremoval ratesurface quality
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