碱性抛光液中铜和钽CMP的去除速率控制和电偶腐蚀研究  

Study on removal rate control and galvanic corrosion of Cu and Ta during CMP in alkaline slurry

作　　者：李灿 潘国峰 胡连军 王辰伟 刘佳 张鑫博 回广泽 LI Can;PAN Guofeng;HU Lianjun;WANG Chenwei;LIU Jia;ZHANG Xinbo;HUI Guangze(School of Electronic and Information Engineering,Hebei University of Technology,Tianjin 300130,China;不详)

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：《电镀与涂饰》2020年第23期1659-1666,共8页Electroplating & Finishing

基　　金：国家科技重大专项(2016zx02301003-004-007);河北省自然科学基金(F2020202067);河北省高等学校科学技术研究重点项目(ZD2016123)。

摘　　要：研究了不同浓度的高碘酸钾(KIO4)和配位剂柠檬酸钾对Cu和Ta的去除速率及腐蚀电位差的影响。由化学机械抛光(CMP)实验结果可知,随着KIO4浓度的提高,Cu的去除速率一直上升,而Ta的去除速率先上升后下降。在pH为10的情况下,当柠檬酸钾为30 mmol/L,KIO4为3 mmol/L时,Cu和Ta的去除速率分别为31.3 nm/min和58.8 nm/min。柠檬酸钾与KIO4的协同作用能够明显提高Ta的去除速率,有利于更好地实现Cu和Ta去除速率的选择性,但此时Cu和Ta之间的腐蚀电位差高达186 mV。为了改善Cu和Ta抛光后的表面形貌,尝试加入表面活性剂十二烷基硫酸铵(ADS)。当ADS的添加量为15 mL/L时,Cu和Ta的去除速率非常接近,分别为46.4 nm/min和49.6 nm/min。模拟CMP过程的动态电化学测试结果显示此时Cu和Ta之间的腐蚀电位差只有11 mV,表明加入ADS能够较好地减轻Cu和Ta之间的电偶腐蚀。The effects of different concentrations of potassium periodate(KIO4)and potassium citrate(a coordination agent)on the removal rates of Cu and Ta and their corrosion potential difference were studied.The results of CMP(chemical mechanical polishing)experiment showed that,with the increasing of KIO4 concentration,the removal rate of Cu was always increased,while the removal rate of Ta was increased initially and then decreased.The removal rate was 31.3 nm/min for Cu and 58.8 nm/min for Ta in a slurry containing potassium citrate 30 mmol/L and KIO43 mmol/L at pH 10.The synergy of potassium citrate and KIO4 obviously increases the removal rate of Ta,which is conducive to the selectivity of Cu and Ta removal rates,but the corrosion potential difference between Cu and Ta is as high as 186 mV.To improve the surface morphologies of the polished Cu and Ta,ammonium dodecyl sulfate(ADS),a surfactant,was added to the slurry.The removal rates of Cu and Ta were 46.4 nm/min and 49.6 nm/min respectively,which was close to 1:1,when the volume fraction of ADS was 15 mL/L.The results of dynamic electrochemical test simulating the CMP process showed that the corrosion potential difference between Cu and Ta was only 11 mV,indicating that ADS could better reduce the galvanic corrosion of Cu and Ta.

关 键 词：铜 钽 化学机械抛光 去除速率 高碘酸钾 十二烷基硫酸铵 腐蚀电位 电偶腐蚀 

分 类 号：TG715[金属学及工艺—刀具与模具]