(1. 常州大学机械工程学院，常州 213164；
2. 常州大学材料科学与工程学院，常州 213164)
摘 要: 以阳离子表面活性剂CTAB为牺牲模板、TEOS为硅源、硝酸铵/乙醇混合溶液为选择性溶剂，合成以表面经PVP修饰的聚苯乙烯(Polystyrene, PS)微球为内核、表面包覆介孔氧化硅(Mesoporous-silica, MSiO2)壳层的新型PS/MSiO2复合磨料。采用场发射扫描电镜(FESEM)、透射电镜(TEM)和原子力显微镜(AFM)测试，研究PS/MSiO2复合磨料的核壳结构以及经复合磨料抛光后的表面粗糙度均方根值和抛光速率。结果表明：PS/MSiO2复合磨料具有包覆完整的核壳结构，其PS内核尺寸为200~210 nm，介孔氧化硅壳层厚度约为30 nm，包覆层中存在大量放射状介孔孔道。氮气吸附/脱附测试表明：复合磨料的比表面积为612 m2/g，介孔孔径为2~3 nm；经复合磨料抛光后衬底表面粗糙度均方根值(RMS)和抛光速率(MRR)分别为0.252 nm和141 nm/min，明显优于粒径相当的常规SiO2磨料(0.317 nm, 68 nm/min)。复合磨料中有机内核及壳层中的介孔孔道结构有利于降低颗粒的弹性模量和表面硬度，从而有助于减小磨料在衬底表面的压痕深度并降低抛光表面粗糙度。此外，复合磨料可借助其高比表面积提高对抛光液中有效化学组分的吸附能力，从而增强接触微区内的化学反应活性以提高抛光速率。
关键字: 聚苯乙烯；介孔氧化硅；核壳结构；复合磨料；化学机械抛光
（1. School of Mechanical Engineering, Changzhou University, Changzhou 213164, China;
2. School of Materials Science and Engineering, Changzhou University, Changzhou 213164, China）
Abstract:The novel composite abrasives containing polyvinylpyrrolidone modified polystyrene (PS) cores and mesoporous silica (MSiO2) shells were synthesized using cetyltrimethylammonium bromide as sacrificial template, tetraethoxysilane as Si source and ammonium nitrate/alcohol mixed solution as selective solvent. The core-shell structure of PS/MSiO2 composites and the root-mean-square and polishing rate were investigated by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and atomic force microscopy. The results show that the obtained PS/MSiO2 composites exhibit a well-defined core-shell structure, and the PS cores with size of 200-210 nm are coated by mesoporous silica shells with thickness of 30 nm with radial meso-channels. As confirmed by N2 adsorption-desorption measurement, the specific surface area and pore size of the composites are 612 m2/g and 2-3 nm, respectively. The oxidized silicon wafer after polishing with PS/MSiO2 composite abrasives presents a lower root-mean-square surface roughness (0.252 nm) and much higher material remvoal rate (141 nm/min) than those of conventional solid SiO2 abrasives with comparable partilce size (0.317 nm, 68 nm/min). The reduced indentation depth and surface roughness might be contributed to the low elastic modulus and surface hardness coming from polymer cores andMSiO2 shells. Meanwhile, the material removal rate is improved due to the mesoporous silica shells of the PS/MSiO2 composites, which might be help to adsorb more active chemical constituents in slurry and enhance chemical reactivity.
Key words: polystyrene; mesoporous silica; core-shell structure; composite abrasive; chemical mechanical polishing
