柠檬酸对CeO_(2)磨料分散稳定性及抛光性能的影响  

Effects of Citric Acid on the Dispersion Stability and Polishing Performance of CeO;Abrasive

作　　者：续晨 周建伟 王辰伟 田源 李越 崔志慧 李森 Xu Chen;Zhou Jianwei;Wang Chenwei;Tian Yuan;Li Yue;Cui Zhihui;Li Sen(School of Electronic and Information Engineering,Hebei University of Technology,Tianjin 300130,China;Tianjin Key Laboratory of Electronic Materials and Devices,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》2022年第2期111-116,共6页Semiconductor Technology

基　　金：国家自然科学基金资助项目(62074049)。

摘　　要：采用柠檬酸作为pH调节剂和分散剂,针对CeO_(2)磨料水溶液的分散性差以及浅沟槽隔离(STI)化学机械抛光(CMP)过程中正硅酸乙酯(TEOS)/氮化硅(Si_(3)N_(4))的去除速率选择性难以控制的问题进行了研究。分散实验结果表明,由于柠檬酸可以结合在CeO_(2)颗粒表面从而极大提高了CeO_(2)磨料的空间位阻,CeO_(2)溶液的分散稳定性得到提升,因此,与酒石酸、硝酸和磷酸相比,在CeO_(2)溶液中使用柠檬酸作为pH调节剂,可以使CeO_(2)磨料具有更小的粒径和较低的分散度以及使CeO_(2)溶液具有较高绝对值的Zeta电位。抛光实验结果表明,柠檬酸可以极大抑制Si_(3)N_(4)的去除速率,且对TEOS的去除速率影响较小,因此,使用柠檬酸作为pH调节剂和分散剂能实现TEOS/Si_(3)N_(4)的高去除速率选择比。同时抛光后TEOS和Si_(3)N_(4)薄膜具有良好的表面形貌和低的表面粗糙度。Citric acid was used as the pH regulator and dispersant to study the poor dispersion of CeO_(2)abrasive aqueous solution and the difficulty in controlling the removal rate selectivity of ethyl silicate(TEOS)/silicon nitride(Si_(3)N_(4))during shallow trench isolation(STI)chemical mechanical polishing(CMP).Dispersion experiment results show that citric acid can be combined on the surface of CeO_(2)particles,which greatly improves the steric hindrance of CeO_(2)abrasive,thus improving the dispersion stability of CeO_(2)solution.Therefore,compared with tartaric acid,nitric acid and phosphoric acid,the use of citric acid as the pH regulator in CeO_(2)solution can make the CeO_(2)abrasive have smaller particle size and lower dispersion and make the CeO_(2)solution have higher absolute value of Zeta potential.Polishing experiment results show that citric acid can greatly inhibit the removal rate of Si_(3)N_(4)and has little influence on the removal rate of TEOS.Therefore,the use of citric acid as the pH regulator and dispersant can achieve high removal rate selection ratio of TEOS/Si_(3)N_(4).Meanwhile,the polished TEOS and Si_(3)N_(4)films have good surface morphology and low surface roughness.

关 键 词：浅沟槽隔离(STI) 化学机械抛光(CMP) CeO_(2) 分散 柠檬酸 速率选择性 

分 类 号：TN305.2[电子电信—物理电子学]