阻挡层CMP中铜钴电偶腐蚀的影响因素  

Influencing Factors of the Galvanic Corrosion Between Cu and Co in the Barrier Chemical Mechanical Polishing

作　　者：付蕾[1,2] 刘玉岭[1,2] 王辰伟[1,2] 张文倩[1,2] 马欣[1,2] 韩丽楠 

机构地区：[1]河北工业大学电子信息工程学院,天津300130 [2]天津市电子材料与器件重点实验室,天津300130

出　　处：《微纳电子技术》2017年第7期492-498,504,共8页Micronanoelectronic Technology

基　　金：国家科技重大专项子课题资助项目(2016ZX02301003-004-007);河北省自然科学基金青年基金资助项目(F2015202267);河北工业大学优秀青年科技创新基金资助项目(2015007);天津市电子材料与器件重点实验室资助项目

摘　　要：在Co化学机械抛光(CMP)过程中,Co的化学反应活性强于Cu,Co/Cu界面存在较大的电化学腐蚀电位差。采用动电位扫描电化学技术,表征金属铜钴表面的电化学反应。采用降低Cu/Co接触腐蚀电位差的方法,表征铜钴电偶腐蚀。研究了阻挡层CMP中影响铜钴电偶腐蚀的几个因素:pH值、H_2O_2和FA/O螯合剂;并对其控制机理进行了深入的研究。实验结果表明:pH值对钴的腐蚀电位影响较大,对铜的腐蚀电位影响不大,随着pH值的增加降低了铜和钴的腐蚀电位差;在碱性环境下,H_2O_2可降低Cu和Co的腐蚀电位差(最小可降到3 mV),可有效抑制Cu和Co之间电偶腐蚀现象的产生;在H_2O_2基电解液中添加适量的FA/O螯合剂有助于降低Cu和Co的腐蚀电位差,对抑制Cu和Co电偶腐蚀现象的产生具有重大的作用。During the Co chemical mechanical polishing（CMP）process,the chemical reactivity of Co is stronger than that of Cu,and a large electrochemical corrosion potential difference exists at the Co/Cu interface.The electrochemical reactions of the metal Cu and Co surfaces were characterized by the electrochemical potentiodynamic scanning technology.The galvanic corrosion between Cu and Co was characterized by the method for reducing Cu/Co contact corrosion potential difference.The several factors influencing the galvanic corrosion between Cu and Co in the barrier CMP were studied,such as the pH value,H2O2 and FA/O chelating agent,and the control mechanisms were researched.The experimental results show that the pH value has a great impact on the corrosion potential of Co,and has little impact on the corrosion potential of Cu.With the increase of pH value,the corrosion potential difference between Cu and Co decreases.In alkaline environments,the corrosion potential difference between Cu and Co decreases with the H2O2（the minimum can be reduced to 3 mV）,and the galvanic corrosion phenomenon between Cu and Co is effectively restrained.The corrosion potential difference between Cu and Co decreases in the H2O2-based electrolyte with additive of the FA/O chelating agent,and the galvanic corrosion phenomenon between Cu and Co is also effectively restrained.

关 键 词：钴 铜 电化学 电偶腐蚀 化学机械抛光(CMP) H2O2 

分 类 号：TN305.2[电子电信—物理电子学]