Abstract The chemical mechanical polishing (CMP) of Cu/Co/TaN barrier liner stack of the sub-14nm devices was associated with several challenges, one of which was to screen out the desired slurries formulation. In this paper, the preliminary screening of cobalt (Co) slurries, combined with the orthogonal test method, was reported systematically for the first time. Based on this, the effects of SiO2, H2O2, potassium tartrate, and TT-LYK on the Co removal rates (RRs) were investigated. The corrosion and polishing behavior of the Co in the slurries containing the above additives were investigated by in-situ OCP measurements, potentiodynamic measurements, and polishing experiments. X-ray photoelectron spectroscopy (XPS) measurements were performed to characterize the complexation mechanism between Co and potassium tartrate. It was found that the slurries containing 5 wt% SiO2, 1 wt% H2O2, and 1.2 wt% PT with 900 ppm TT-LYK at pH 9 was a better candidate for Co barrier planarization and effective in minimizing the galvanic corrosion of Co and Cu under Polishing conditions. Finally, Cu/Co/TaN wafers polished with the candidate slurries showed a good RR selectivity. And the atomic force microscopy (AFM) measurements showed excellent post-polish surfaces.

中文翻译：

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酒石酸钾作为络合剂，用于化学机械抛光 H2O2 基碱性浆料中的 Cu/Co/TaN 势垒衬垫叠层

摘要 亚 14nm 器件的 Cu/Co/TaN 势垒衬垫叠层的化学机械抛光 (CMP) 与若干挑战相关，其中之一是筛选出所需的浆料配方。本文首次系统地报道了钴（Co）浆料的初步筛选，并结合正交试验方法。在此基础上，研究了 SiO2、H2O2、酒石酸钾和 TT-LYK 对 Co 去除率 (RR) 的影响。通过原位 OCP 测量、动电位测量和抛光实验研究了含有上述添加剂的浆料中 Co 的腐蚀和抛光行为。进行 X 射线光电子能谱 (XPS) 测量以表征 Co 和酒石酸钾之间的络合机制。发现含有 5 wt% SiO2、1 wt% H2O2 和 1.2 wt% PT 以及 900 ppm TT-LYK 在 pH 值为 9 的浆料是 Co 势垒平面化的更好候选者，并能有效减少 Co 和 Cu 的电偶腐蚀在抛光条件下。最后，用候选浆料抛光的 Cu/Co/TaN 晶片显示出良好的 RR 选择性。原子力显微镜 (AFM) 测量表明抛光后表面非常好。