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报道了一种用于技术节点为28 nm的集成电路多层铜互连阻挡层化学机械平坦化(CMP)的弱碱性抛光液(pH值为8.5),仅由平均粒径为20 nm的硅溶胶、FA/O多羟多胺螯合剂及非离子表面活性剂组成。实验结果表明,研发的弱碱性阻挡层抛光液对牺牲层SiO2、阻挡层Ta及金属互连线Cu等多种材料具有优异的速率选择性,去除速率一致性大于95%,并在28 nm多层铜布线片阻挡层CMP后具有较高的平坦化性能,分别获得了20 nm以下深度的碟形坑和蚀坑。通过电化学极化曲线测试表明,此弱碱性阻挡层抛光液能有效减少Cu和Ta之间的腐蚀电位差,并避免了铜互连结构Cu和Ta界面处电偶腐蚀的产生,这对提高集成电路芯片可靠性具有重要意义。
A weakly alkaline polishing solution (pH 8.5) for chemical mechanical planarization (CMP) of a multi-layer copper interconnection barrier in integrated circuits with a technology node of 28 nm was reported, consisting only of an average particle size of 20 nm Silica sol, FA / O polyhydric polyamine chelating agent and non-ionic surfactant. The experimental results show that the developed weakly alkaline barrier layer polishing slurry has excellent rate selectivity for a variety of materials, such as sacrificial layer SiO2, barrier layer Ta and metal interconnection Cu, with a removal rate agreement greater than 95% The multi-layer copper wiring barrier layer CMP has a higher planarization performance, were obtained under the depth of 20 nm dish crater and pit. Electrochemical polarization curve test showed that the weak alkaline barrier layer polishing solution can effectively reduce the potential difference between Cu and Ta and avoid the galvanic corrosion at Cu and Ta interface. It is very important to improve the reliability of integrated circuit chip.