聚甲基丙烯酸对STI CMP中SiO_(2)和Si_(3)N_(4)去除速率选择比的影响  

Effect of Polymethacrylic Acid on the Removal Rate Selectivity of SiO_(2) and Si_(3)N_(4) in STI CMP

作　　者：李相辉 张祥龙 孟妮 聂申奥 邱宇轩 何彦刚 Li Xianghui;Zhang Xianglong;Meng Ni;Nie Shen'ao;Qiu Yuxuan;He Yangang(School of Electronic Information Engineering,Hebei University 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》2024年第2期131-137,共7页Semiconductor Technology

基　　金：国家科技重大专项(2016ZX02301003-004-007);河北省自然科学基金(F2018202133)。

摘　　要：在浅沟槽隔离(STI)化学机械抛光(CMP)中,需要保证极低的Si_(3)N_(4)去除速率,以及相对较高的SiO_(2)去除速率,并且要达到SiO_(2)与Si_(3)N_(4)的去除速率选择比大于30的要求。在CeO_(2)磨料质量分数为0.25%,抛光液pH=4的前提下,研究了聚甲基丙烯酸(PMAA)对SiO_(2)与Si_(3)N_(4)去除速率以及二者去除速率选择比的影响,分析了PMAA在影响SiO_(2)与Si_(3)N_(4)去除速率过程中的作用机理。结果表明,PMAA的加入可以降低SiO_(2)与Si_(3)N_(4)的去除速率,当PMAA的质量分数为120×10^(-6)时,SiO_(2)和Si_(3)N_(4)的去除速率分别为185.4 nm/min和3.0 nm/min,去除速率选择比为61。抛光后SiO_(2)与Si_(3)N_(4)晶圆表面有较好的表面粗糙度,分别为0.290 nm和0.233 nm。In shallow trench isolation(STI)chemical mechanical polishing(CMP),it is necessary to ensure an extremely low Si_(3)N_(4) removal rate and a relatively high SiO_(2) removal rate,while achieving a removal rate selectivity ratio of SiO_(2) to Si_(3)N_(4) greater than 30.The influences of poly-methacrylic acid(PMAA)on the removal rates of SiO_(2) and Si_(3)N_(4),as well as the selectivity ratio between the two were investigated under the conditions of CeO_(2) abrasive mass fraction of 025%and slurry pH of 4.The mechanism of PMAA in affecting the removal rates of SiO_(2) and Si_(3)N_(4) was analyzed.The results indicate that the addition of PMAA can decrease the removal rates of SiO_(2) and Si_(3)N_(4).When the mass fraction of PMAA is 120×10^(-6),the removal rates of SiO_(2) and Si_(3)N_(4) are 1854 nm/min and 30 nm/min,respectively,resulting in a removal rate selectivity ratio of 61.After polishing,SiO_(2) and Si_(3)N_(4) wafers exhibit favorable surface roughness values of 0290 nm and 0233 nm,respectively.

关 键 词：浅沟槽隔离(STI) 化学机械抛光(CMP) 二氧化硅(SiO_(2)) 氮化硅(Si_(3)N_(4)) 聚甲基丙烯酸(PMAA) 去除速率选择比 

分 类 号：TN305.2[电子电信—物理电子学]