Abstract

With the rapid development of semiconductors, the number of materials needed to be polished sharply increases. The material properties vary significantly, posing challenges to chemical mechanical polishing (CMP). Accordingly, the study aimed to classify the material removal mechanism. Based on the CMP and atomic force microscopy results, the six representative metals can be preliminarily classified into two groups, presumably due to different material removal modes. From the tribology perspective, the first group of Cu, Co, and Ni may mainly rely on the mechanical plowing effect. After adding H₂O₂, corrosion can be first enhanced and then suppressed, affecting the surface mechanical strength. Consequently, the material removal rate (MRR) and the surface roughness increase and decrease. By comparison, the second group of Ta, Ru, and Ti may primarily depend on the chemical bonding effect. Adding H₂O₂ can promote oxidation, increasing interfacial chemical bonds. Therefore, the MRR increases, and the surface roughness decreases and levels off. In addition, CMP can be regulated by tuning the synergistic effect of oxidation, complexation, and dissolution for mechanical plowing, while tuning the synergistic effect of oxidation and ionic strength for chemical bonding. The findings provide mechanistic insight into the material removal mechanism in CMP.

中文翻译：

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化学机械抛光中的两种材料去除模式：机械犁耕与化学键合

摘要

随着半导体的快速发展，需要抛光的材料数量急剧增加。材料特性差异很大，给化学机械抛光（CMP）带来了挑战。因此，该研究旨在对材料去除机制进行分类。根据 CMP 和原子力显微镜结果，六种有代表性的金属可以初步分为两类，大概是由于材料去除模式不同。从摩擦学角度来看，第一组Cu、Co、Ni可能主要依靠机械犁耕效应。添加H ₂ O ₂后，腐蚀先增强后抑制，影响表面机械强度。因此，材料去除率 (MRR) 和表面粗糙度会增加或减少。相比之下，第二组Ta、Ru和Ti可能主要取决于化学键合效应。添加H ₂ O ₂可以促进氧化，增加界面化学键。因此，MRR 增加，表面粗糙度降低并趋于平稳。此外，可以通过调节机械犁耕的氧化、络合和溶解的协同效应，同时调节化学键合的氧化和离子强度的协同效应来调节CMP。这些发现为 CMP 中的材料去除机制提供了深入的了解。