纳米氧化铈抛光液对钌的化学机械抛光

摘要

采用液相沉淀法制备了纳米CeO2磨料,利用X射线衍射(XRD)表征其物相组成.通过纳米粒度仪研究了分散剂种类、热处理温度对CeO2磨料制备的悬浮液的粒径分布和Zeta电势的影响.用由CeO2磨料制备的抛光液对钌进行化学机械抛光,采用原子力显微镜观察钌片表面的微观形貌.结果表明:制备的粉体是具有立方萤石型结构的纳米CeO2,其晶粒尺寸随热处理温度的升高而增大；CeO2磨料在以六偏磷酸钠(SHMP)作为分散剂的悬浮液中分散效果最好；在抛光压力为6.9 kPa,抛光台转速为50 r/min,抛光液流量为50 mL/min,抛光液pH值为10.0,抛光液主要组成(质量分数)为1％ CeO2,1％(NH4)2S2O8,0.01％ SHMP的条件下,钌的抛光速率达到9.0 nm/min,表面粗糙度Ra值为2.2 nm.%Nano-CeO2 abrasives were prepared by liquid phase precipitation. The phase composition of the samples was characterized by X-ray diffraction ( XRD). The effects of the dispersant species and the heat treatment temperature on the average particle size and the zeta potential of CeO2 suspensions were investigated by particle size analyzer. The nano-CeO2 abrasive slurry was used for chemical mechanical polishing ( CMP) on ruthenium. The surface of ruthenium was characterized by atomic force microscopy (AFM). The results showed that the prepared powders were nano-CeO2 with cubic fluorite structure, and the average particle size of CeO2 increased with the increase of the heat treatment temperature. The dispersibility of nano-CeO2 was the best in sodium hexametaphosphate (SHMP). The material removal rate (MRR) for ruthenium CMP could reach 9.0 nm/ min and the surface roughness Ra of the polished ruthenium could reach 2. 2 nm under the following conditions; the pressure was 6.9 kPa, the rotation speed was 50 r/min, the slurry flow was 50 mL/min, the slurry pH was 10.0 and the slurry consisted of 1% CeO2, 1% (NH4) 2S2O8, 0.01% SHMP (mass fraction).