不同络合剂与pH值对钴CMP去除速率的影响  

Effects of Different Complexing Agents and pH Values on Cobalt Removal Rate in CMP

作　　者：杨云点 王胜利 王辰伟 程远深 雷双双 李森 Yang Yundian;Wang Shengli;Wang Chenwei;Cheng Yuanshen;Lei Shuangshuang;Li Sen(School of Electronic Information Engineering,Hebei Universiy of Technology,Tianjin 300130,China;Tianjin Key Laboratory of Electronic Materials and Derices,Tianjin 300130,China)

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：《半导体技术》2020年第7期543-549,共7页Semiconductor Technology

基　　金：国家科技重大专项资助项目(2019ZX02308,2016ZX02301003-004-007);河北省自然科学基金资助项目(E2019202367)。

摘　　要：研究不同络合剂(如甘氨酸(Gly)、柠檬酸(CA)、酒石酸(TA))在不同pH值的抛光液中对钴(Co)化学机械抛光(CMP)去除速率的影响。研究结果表明,采用不同络合剂时,随着pH值的升高,Co的去除速率均逐渐降低。当采用甘氨酸作为络合剂时,Co的去除速率优于柠檬酸和酒石酸,当pH值为8时,Co的去除速率可达628 nm/min,粗糙度为1.08 nm,随着pH值由8升高到10,Co的去除速率降低到169.9 nm/min。电化学实验表明,采用不同络合剂时,随着pH值升高,开路电位逐渐变大,电荷传递电阻逐渐增大,这是由于Co表面的氧化物如四氧化三钴、氢氧化高钴增多,钝化膜逐渐加厚且更为致密,络合剂的络合作用减弱。同时,在pH值为8时,采用甘氨酸作为络合剂时,Co的开路电位为负值(-0.428 V),电荷传递电阻为0.943 9Ω,表明Co表面氧化膜薄且致密性差,更容易被腐蚀去除。The effects of different complexing agents,such as glycine(Gly),citric acid(CA) and tartaric acid(TA) on the removal rate of cobalt(Co) in chemical mechanical polishing(CMP) with different pH values of slurries were studied. The research results show that the removal rate of Co gradually decreases with the increase of pH value by using different complexing agents. When using glycine as the complexing agent, the removal rate of Co is higher than that of citric acid and tartaric acid. When the pH value is 8, the removal rate of Co reaches 628 nm/min, the roughness is 1.08 nm. With the increase of pH value from 8 to 10, the removal rate of Co decreases to 169.9 nm/min. The electrochemical experiments show that with different complexing agents, the open circuit potential decreases with the increase of pH value, and the charge transfer resistance gradually increases. This is due to the increase of the oxide on the surface, such as cobaltosic oxide and the coballtic hydroxide, the thickening of the passive film and the decrease of complexing effect of complexing agent. When the pH value is 8 and the glycine is used as the complexing agent, the open circuit potential of Co is negative(-0.428 V) and the charge transfer resistance is 0.943 9 Ω. The results show that the oxide film on the surface of Co is thin and less dense, which is easier to be removed by corrosion.

关 键 词：钴(Co) 络合剂 化学机械抛光(CMP) 去除速率 PH值 

分 类 号：TN305.2[电子电信—物理电子学]