(1. 常州大學(xué)機(jī)械工程學(xué)院，常州 213164；
2. 常州大學(xué)材料科學(xué)與工程學(xué)院，常州 213164)
摘 要: 以陽(yáng)離子表面活性劑CTAB為犧牲模板、TEOS為硅源、硝酸銨/乙醇混合溶液為選擇性溶劑，合成以表面經(jīng)PVP修飾的聚苯乙烯(Polystyrene, PS)微球?yàn)閮?nèi)核、表面包覆介孔氧化硅(Mesoporous-silica, MSiO2)殼層的新型PS/MSiO2復(fù)合磨料。采用場(chǎng)發(fā)射掃描電鏡(FESEM)、透射電鏡(TEM)和原子力顯微鏡(AFM)測(cè)試，研究PS/MSiO2復(fù)合磨料的核殼結(jié)構(gòu)以及經(jīng)復(fù)合磨料拋光后的表面粗糙度均方根值和拋光速率。結(jié)果表明：PS/MSiO2復(fù)合磨料具有包覆完整的核殼結(jié)構(gòu)，其PS內(nèi)核尺寸為200~210 nm，介孔氧化硅殼層厚度約為30 nm，包覆層中存在大量放射狀介孔孔道。氮?dú)馕?脫附測(cè)試表明：復(fù)合磨料的比表面積為612 m2/g，介孔孔徑為2~3 nm；經(jīng)復(fù)合磨料拋光后襯底表面粗糙度均方根值(RMS)和拋光速率(MRR)分別為0.252 nm和141 nm/min，明顯優(yōu)于粒徑相當(dāng)?shù)某Ｒ?guī)SiO2磨料(0.317 nm, 68 nm/min)。復(fù)合磨料中有機(jī)內(nèi)核及殼層中的介孔孔道結(jié)構(gòu)有利于降低顆粒的彈性模量和表面硬度，從而有助于減小磨料在襯底表面的壓痕深度并降低拋光表面粗糙度。此外，復(fù)合磨料可借助其高比表面積提高對(duì)拋光液中有效化學(xué)組分的吸附能力，從而增強(qiáng)接觸微區(qū)內(nèi)的化學(xué)反應(yīng)活性以提高拋光速率。
關(guān)鍵字: 聚苯乙烯；介孔氧化硅；核殼結(jié)構(gòu)；復(fù)合磨料；化學(xué)機(jī)械拋光
（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
