Application of surface analysis in study on removal mechanism and abrasive selection during fused silica chemical mechanical polishing
Application of surface analysis in study on removal mechanism and abrasive selection during fused silica chemical mechanical polishing
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表面分析在熔融石英化学机械抛光去除机理及磨料选择研究中的应用
DOI：
10.1002/sia.6625
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发表时间：
2019-05-01
影响因子：
1.7
通讯作者：
Pan, Guoshun
中科院分区：
文献类型：
--
作者：
Chen, Gaopan;Luo, Haimei;Pan, Guoshun
本文采用表面分析技术对熔融石英化学机械抛光（CMP）过程中的去除机理和磨料的选择进行了研究。用扫描电子显微镜（SEM）观察了磨料的形貌。使用原子力显微镜（AFM）来确定抛光的熔融石英表面的表面粗糙度（Rq）和起伏（PV）。结果表明，磨料形貌对去除率和PV有很大影响，但对去除率影响不大。AFM和红外光谱（IR）分析表明，抛光表面存在一层称为“硅胶膜（SGM）”的软层，这是CMP过程中MRR、Rq和PV差异的关键原因。对于三种微氧化铈磨料，具有粗糙表面的磨料获得更多机会接触熔融石英表面，从而产生更高的MRR。对于不同种类的纳米磨料，由于更高的化学反应速率，存在由纳米氧化铈磨料诱导的更多SGM。使用X射线光电子能谱（XPS）对抛光的熔融石英上的元素污染进行了评估，结果表明，在使用纳米氧化铈和纳米氧化铝磨料的熔融石英抛光表面上分别存在3.6和5.4 nm的元素污染。而由纳米二氧化硅抛光的表面没有异质元素污染。在此基础上，通过改变纳米二氧化硅的化学组成，设计了一种新型抛光液。与氧化铈基浆料相比，硅基浆料在熔石英精密加工中具有更好的去除效率和表面质量。
In this work, surface analysis technology is employed to investigate the removal mechanism and the selection of abrasive during fused silica chemical mechanical polishing (CMP). Morphology of abrasives is inspected by scanning electron microscope (SEM). The atomic force microscope (AFM) is used to determine the surface roughness (Rq) and undulating (PV) of the polished fused silica surface. The results show that abrasive morphology has a tremendous influence on removal rate (MRR) and PV but has little effect on the Rq. The AFM and infrared spectroscopy (IR) analysis show that a soft layer, called “silica gel membrane (SGM),” existed on the polished surface is the critical reason for the differences of MRR, Rq, and PV during CMP. For three kinds of micro‐ceria abrasives, the abrasive with a rougher surface gets more opportunities to contact the surface of fused silica, yielding higher MRR. Regarding different kinds of nano‐abrasives, there are more SGM induced by nano‐ceria abrasive resulting from higher chemical reaction rate. The element contaminations on the polished fused silica have been assessed using X‐ray photoelectron spectroscopy (XPS), and the results suggest that there are depths of 3.6 and 5.4‐nm element contaminations on the polished surface of fused silica with nano‐ceria and nano‐alumina abrasives, respectively. While the surface polished by nano‐silica is free of heterogeneous element contaminations. Based on study results, a novel polishing slurry is designed by modifying the chemical composition of nano‐silica. Comparing with ceria‐based slurry, the silica‐based slurry has better removal efficiency, and surface quality in fused silica precision machining.