铜互连线低磨料化学机械平坦化机制  

Mechanism for Copper Interconnections Chemical Mechanical Planarization at Low Concentration of Abrasive

作　　者：李炎[1] 张宏远[1] 刘玉岭[1] 王傲尘[1] 李洪波[1] 

机构地区：[1]河北工业大学微电子技术与材料研究所,天津300130

出　　处：《稀有金属》2015年第11期1048-1055,共8页Chinese Journal of Rare Metals

基　　金：国家中长期科技发展规划02科技重大专项(2009ZX02308);河北省自然科学基金项目(E2013202247;F2012202094);河北省教育厅基金项目(2011128)资助

摘　　要：主要研究了低磨料浓度下铜互连线的平坦化机制,建立了凸处和凹处的铜膜去除模型,并在MIT 854铜布线片上进行了验证实验,进一步证明了机制模型的正确性。在工作压力存在的条件下,凸处铜膜的去除以化学机械作用为主,凹处铜膜去除以化学作用为主,由此得出,在忽略机械作用对化学反应增益作用的前提下,低磨料浓度有利于得到较高的高低处速率差,进而实现晶圆的表面平坦化。在MIT 854铜布线片上进行了实验验证,实验证明,当磨料浓度为0.5%时,铜膜的去除速率已达到最大值,此时,线宽/线间距(L/S)为100μm/100μm,50μm/50μm和10μm/10μm的铜线条剩余高低差分别由初始的470,460和450 nm变为平坦化后的30.0,15.0和3.1 nm,另外还得出宽线条比窄线条对抛光液的利用率要高,为了实现进一步的平坦化,提高窄线条区域对抛光液的利用率成为重中之重。Planarization mechanism of copper interconnections at low abrasive concentration was mainly studied, and the copper film removal models of the convex and concave positions were established. The validation experiments were conducted on the MIT 854 copper multi-layered wafers, which further proved the correctness of the mechanism. Under the work pressure, convex copper film removal was mainly decided by chemical mechanical action , concave copper film removal was mainly decided by chemical action, and thus, low abrasive concentration was conducive to a higher rate of difference without considering the gain effect of mechanical action on the chemi- cal action, leading to the realization of the wafer surface planarization. Validation experiments on the MIT 854 copper multi-layered wafers showed that, when the abrasive concentration was 0.5% , the removal rate Of copper film reached the maximum Value. Then the remaining height differences of the copper strip whose line width/line space （L/S） were 100 μm/100 μm, 50 μm/50 μm and 10 μm/ 10 μm, respectively, decreased from the initial 470, 460 and 450 nm to 30.0 nm, 15.0 nm and 3.1 nm after planarization. It was found that utilization rate of the wide line on the slurry was higher than that of the narrow line. In order to achieve further planarization, improving the utilization rate of narrow line region on the slurry became the priority.

关 键 词：低磨料浓度 化学机械平坦化 机械作用 化学作用 铜互连线 

分 类 号：TN43[电子电信—微电子学与固体电子学] TN47