制备、表征及其化学机械抛光性能
(1. 常州大学 材料科学与工程学院,常州 213164;2. 苏州科技学院 化学与生物工程学院,苏州 215011)
摘 要: 以无皂乳液聚合法制备的不同粒径聚苯乙烯(Ploystrene, PS)微球为内核,以硝酸铈和六亚甲基四胺为原料,采用液相工艺制备具有核壳结构的PS-CeO2复合微球。利用X射线衍射仪(XRD)、透射电子显微镜(TEM)、场发射扫描电镜(FESEM)、傅里叶转换红外光谱仪(FT-IR)和热重分析仪(TGA)等对样品的成分、物相结构、形貌、粒径以及团聚情况进行表征。将所制备的PS-CeO2复合微球作为磨料用于二氧化硅介质层的化学机械抛光,用原子力显微镜(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3种PS微球呈单分散规则球形,粒径分别约为120、170和240 nm;3种PS-CeO2复合微球具有核壳结构,粒径分别约为140、190和260 nm,CeO2壳厚约为10 nm。随着PS-CeO2复合磨料粒径的减小,抛光表面粗糙度随之降低,经样品F1抛光后表面在10 μm×10 μm面积范围内粗糙度的平均值(Ra)及其均方根(Rms)分别为0.372和0.470 nm。
关键字: PS-CeO2复合磨料;核壳结构;化学机械抛光
core-shell PS-CeO2 composite abrasives with different particle sizes
(1. School of Materials Science and Engineering, Changzhou University, Changzhou 213164, China;
2. School of Chemistry and Biological Engineering,
Suzhou University of Science and Technology, Suzhou 215011, China)
Abstract:Polystyrene (PS) microspheres were prepared by soap-free emulsion polymerization method. Core-shell structured PS-CeO2 composite microspheres were synthesized by liquid phase process using cerium nitrate and hexamethylene tetramine as raw materials. The composition, phase structure, morphology, grain size and agglomeration of the as-prepared composite microspheres were characterized by XRD, TEM, FESEM, FT-IR and TGA. The as-prepared composite microspheres were collocated into polishing abrasives for chemical mechanical polishing (CMP) of silicon dioxide dielectric layer. The morphologies of the dielectric layer after polishing by the composite abrasives were investigated by AFM. The results indicate that the three kinds of PS microspheres are monodispersive and uniform, and the particle size of PS is about 120, 170 and 240 nm, respectively. The particle size of the three kinds of the as-prepared PS-CeO2 composite microspheres is about 140, 190 and 260 nm, respectively, and the thickness of CeO2 shell is about 10 nm. After CMP, the surface roughness of SiO2 dielectric layer decreases with the decrease of the particle size of the composite microspheres. The average roughness Ra and root mean square of roughness Rms of dielectric layer polished by PS-CeO2 composite abrasives in the area of 10 μm ×10 μm are 0.372 and 0.470 nm, respectively.
Key words: PS-CeO2 composite abrasives; core-shell structure; chemical mechanical polishing (CMP)