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在ULSI多层铜布线中,由于钽与铜在物理及化学性质上的差别导致这两者的CMP去除速率不同,从而在抛光结束后出现蝶形坑等缺陷,影响器件性能。通过实验分析碱性抛光液中磨料、螯合剂、氧化剂、pH值、活性剂对铜与钽CMP选择比的影响。根据铜与钽的CMP去除机理,从实验结果分析出对铜、钽去除速率影响较为明显的成分,调节这些成分得到特定配比的抛光液,分别实现了铜与钽的去除速率相等、铜的去除速率大于钽、铜的去除速率小于钽。使用上述铜去除速率小于钽的抛光液对12英寸(1英寸=2.54 cm)图形片进行抛光,通过原子力显微镜观察,证明了这种抛光液能有效地修复多层布线CMP中的蝶形坑等缺陷。
ULSI multilayer copper wiring, due to the physical and chemical properties of tantalum and copper lead to the difference between the two CMP removal rate, so that after the end of the bow hole defects such as butterfly, the performance of the device. The effects of abrasive, chelating agent, oxidant, pH value and active agent on CMP selectivity of copper and tantalum were analyzed by experiments. According to the CMP removal mechanism of copper and tantalum, the components that have a significant effect on the removal rate of copper and tantalum are analyzed from the experimental results. The polishing compositions with specific compositions are adjusted to achieve the same removal rate of copper and tantalum, respectively, and the copper Removal rate is greater than tantalum, copper removal rate is less than tantalum. Polishing a 12 inch (1 inch = 2.54 cm) pattern piece with the above copper removal rate less than tantalum polishing liquid, it was confirmed by atomic force microscopy that this polishing solution was effective in repairing butterfly pits and the like in the multilayer wiring CMP defect.