Cobalt (Co) with its low resistivity, excellent resistance to electro-migration with co-deposition property and void-free seamless fill ability, pledges to transform the landscape of integrated circuits in many areas, especially in logic contacts and interconnects. Chemical mechanical polishing (CMP), which utilizes the synergistic action of chemical corrosion and mechanical wear, has been recognized as the exclusive manufacturing approach to achieve global and local planarization of wafer surfaces. In this work, we proposed an innovative hydrogen peroxide (HP) polishing slurry, applying phthalic acid as the complexing agent and oleic acid as the corrosion inhibitor at pH 10. From the results of appropriate material removal/static etching rates as well as the smooth surface morphologies, phthalic acid and oleic acid are identified to be qualified in HP-based slurries for heterogeneous materials of Co interconnects. Moreover, the mechanisms of complexation and inhibition have been revealed by electrochemical analysis and X-ray photoelectron spectroscopy tests. It can be concluded that with the addition of complexing agent phthalic acid in HP-based slurries, the transformation of oxidization from low-valence compounds to high-valence was partially replaced by stronger complexing action, making the removal mechanism be attributed to the combined oxidization and complexation. When oleic acid is introduced, it could react with Co oxides to form a polymer protection layer adsorbing on Co films, achieving an inhibition effect to avoid Co excessive corrosion. Meanwhile, the oxidization of HP as well as the complexation of phthalic acid, combined with the protection of oleic acid play critical roles to maintain the appropriate removal rates and selection ratios.

中文翻译：

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邻苯二甲酸和油酸对钴互连线碱性浆料化学机械抛光的作用


钴 (Co) 具有低电阻率、优异的抗电迁移性、共沉积特性和无空隙无缝填充能力，有望改变集成电路在许多领域的格局，特别是在逻辑接触和互连领域。化学机械抛光（CMP）利用化学腐蚀和机械磨损的协同作用，被认为是实现晶圆表面全局和局部平坦化的唯一制造方法。在这项工作中，我们提出了一种创新的过氧化氢 (HP) 抛光浆料，在 pH 10 下使用邻苯二甲酸作为络合剂，使用油酸作为腐蚀抑制剂。从适当的材料去除/静态蚀刻速率以及平滑的结果来看，从表面形貌来看，邻苯二甲酸和油酸被认为适合用于 Co 互连异质材料的 HP 浆料。此外，电化学分析和X射线光电子能谱测试揭示了络合和抑制的机制。由此可见，在HP基浆料中添加络合剂邻苯二甲酸后，氧化从低价化合物向高价化合物的转变部分被更强的络合作用所取代，使得去除机理归因于联合氧化。和络合。当引入油酸时，它可以与Co氧化物反应，形成吸附在Co薄膜上的聚合物保护层，达到缓蚀作用，避免Co过度腐蚀。同时，HP的氧化以及邻苯二甲酸的络合，与油酸的保护相结合，对于保持适当的去除率和选择比发挥着关键作用。