关于FA/O螯合剂降低铜布线片漏电流的研究

简要论述了互连工艺中铜布线取代铝布线的必然趋势,以及铜布线片化学机械抛光(CMP)后进行清洗的必要性。在集成电路制造的过程中,漏电流的危害已经引起了广泛关注。在CMP过程中产生的三种主要表面缺陷对漏电流都有一定的影响,但其中重金属离子对漏电流的影响是最大的。通过使用不同浓度的FA/O螯合剂对铜布线片进行清洗,从而得出最佳的去除金属离子降低漏电流的清洗浓度。为了防止FA/O螯合剂对铜线条造成腐蚀,采用在清洗液中加入缓蚀剂苯并三氮唑(BTA)来有效控制铜线条的表面腐蚀,从而得到理想的清洗结果。25℃时,加入20 mmol/L BTA的体积分数为0.4%的FA/O螯合剂降低漏电流的效果最佳。

Study on Reducing the Leakage Current of Cu Pattern with the FA/O Chelating Agent

The inevitable trend of the copper wiring replacing of the aluminum wiring in the interconnect technology and the necessity of the post-CMP(chemical mechanical polishing) cleaning on the pattern were discussed.The damage of the leakage current was caused widespread concern in the IC manufacturing process.The three major surface defects formed in the process of CMP have certain influences on the leakage current,but the effect of the heavy metal ions is the largest.The optimal concentration to remove the metal ions and reduce the leakage current was obtained by using the FA/O chelating agent with different concentrations on the pattern cleaning.To avoid the copper lines corroded by the FA/O chelating agents,the cleaning fluid with the inhibitor BTA to control the surface erosion of the copper lines was chosen to get the desired clea-ning results.The volume fraction of 0.4% FA/O chelating agent with 20 mmol/L BTA can reduce the leakage current best at 25 ℃.