包覆型CeO_2/SiO_2和CeO_2/聚苯乙烯复合磨料的制备及其化学机械抛光性能

以SiO2和聚苯乙烯(polystyrene,PS)微球为内核,采用液相沉淀工艺制备了具有包覆结构的CeO2/SiO2和CeO2/PS复合颗粒。利用X射线衍射仪、透射电子显微镜、场发射扫描电子显微镜、X射线光电子能谱仪、动态光散射仪和zata电位测定等手段对所制备样品进行了表征。将所制备的CeO2/SiO2和CeO2/PS复合颗粒用于硅晶片热氧化层的化学机械抛光,用原子力显微镜(atomic force microscope,AFM)观察抛光表面的微观形貌、测量表面粗糙度。结果表明:所制备的CeO2/SiO2和CeO2/PS复合颗粒呈球形,粒径在150～200nm,CeO2纳米颗粒在SiO2和PS微球内核表面包覆均匀。包覆的CeO2颗粒与SiO2内核之间形成了化学键结合。CeO2颗粒的包覆显著的改变了复合颗粒的表面电性。AFM测量结果表明:经CeO2/SiO2和CeO2/PS复合磨料抛光后的硅热氧化片表面在5μm×5μm范围内粗糙度值分别为0.292nm和0.180nm。

PREPARATION AND ITS OXIDE CHEMICAL MECHANICAL POLISHING PERFORMANCE OF CERIA-COATED SILICA AND CERIA-COATED POLYSTYRENE NANOPARTICLE

SiO_2 and polystyrene (PS) microspheres were directly coated with CeO_2 by chemical precipitation technique. The as-prepared samples were analyzed by X-ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, X-ray photoelectron spectrometry, dynamic light scattering and zeta potential analysis. The chemical mechanical polishing performance of CeO_2-coated SiO_2 and CeO_2-coated PS composite abrasives to thermal oxide film on Si wafer surface was investigated by atomic force microscopy. The results indicate that the successful preparation of spherical CeO_2-coated SiO_2 and CeO_2-coated PS particles with particle sizes of 150-200 nm and core (SiO_2/PS) uniformly coated by CeO_2. The isoelectric point of the CeO_2-coated SiO_2 and CeO_2-coated PS nanoparticles is about 6.2, 5.9. CeO_2 is chemically bound with SiO_2, and as a result, Si-O-Ce is formed. The surface roughness values within a 5 μm×5μm area of the thermal oxide film polished by CeO_2-coated SiO_2 and CeO_2-coated PS composite abrasives are 0.292 nm and 0.180 nm, respectively.