半导体硅材料CMP三维有限元分析  

Three-Dimensional Finite Element Analysis in Silicon Wafer Chemical Mechanical Polishing Process

作　　者：王新 周旗钢 路一辰 宁永铎 郑宇 王永涛 Wang Xin;Zhou Qigang;Lu Yichen;Ning Yongduo;Zheng Yu;Wang Yongtao(National Engineering Research Center of Key Materials of Integrated Circuit,Bejing 100088;GRINM SemiconductorMaterials Co.,Ltd.,Beijing100088)

机构地区：[1]集成电路关键材料国家工程研究中心,北京100088 [2]有研半导体材料有限公司,北京100088

出　　处：《稀有金属》2023年第9期1324-1330,共7页Chinese Journal of Rare Metals

基　　金：国家重点研发计划项目(2017YFB0305603)资助。

摘　　要：利用有限元仿真方法分析了四轴多片式单面抛光系统的抛光压力分布,建立三维准静态非轴对称模型,设定了模型部件尺寸和材料物性参数,设定模型假设条件和边界约束,使用有限元软件计算不同抛光垫杨氏模量和不同载荷条件下对硅片表面法向应力的影响,实验验证了硅片表面法向应力非均匀性(NSNU)与抛光去除非均匀性(WIWNU)的对应关系。抛光工作状态中抛光盘、陶瓷板的最大形变量为纳米级别,对硅片品质的影响可以忽略不计,抛光垫的最大形变量为微米级,最大形变与抛光垫杨氏模量有相关性,影响硅片的边缘应力分布;不同载荷条件下,硅片表面4个特征路径的应力变化有显著差异,应力分布均匀化趋势并不同步,由此可证明四轴多片式单面抛光系统中硅片表面压力分布的非对称性,这是三维准静态非轴对称有限元模型与二维轴对称方法的显著差异所在。仿真实验找出了NSNU最优化条件,验证了NSNU和WIWNU在不同载荷下具有一致的分布规律,两种实验载荷存在偏差,分析原因是抛光盘表面的平整度难以实现绝对平坦。The rapid development of the integrated circuit industry has put forward higher requirements for silicon wafer surface flatness.Chemical mechanical polishing(CMP)technology was the most important surface processing technology in the semiconductor field and the best process scheme for silicon wafer surface flattening.Polishing accuracy directly affected the quality level of single crystal silicon wafer.During the processing of single crystal silicon substrate,polishing pressure was an important factor that affected the removal of polishing materials and the non-uniformity of removal.The research and analysis object of polishing pressure was not only the overall loading distribution on the back of silicon wafer,but also the property of the polishing pad.Researchers usually used the method of establishing two-dimensional or three-dimensional axisymmetric model to analyze the polishing pressure distribution by finite element method.For the single-side polishing process of 200 mm silicon wafer,the pressure distribution on the silicon wafer surface did not have axisymmetry.In this paper,a three-dimensional quasi-static polishing model was established,and the finite element simulation was carried out to study the polishing pressure distribution and its impact on the within wafer non-uniformity(WIWNU).The polishing pressure distribution of the four axis multi-chip single-side polishing system was analyzed by using the finite element simulation method.In this three-dimensional quasi static model,the polishing pressure was applied to the block,and then transferred to the back surface of the silicon wafer.Used two parts of pressure at the same time to achieve the balanced adjustment of polishing pressure,and the model component size and material property parameters were set.Different element mesh generation methods were used for each component.The radial size of silicon wafer and polishing pad was much greater than the thickness,so it was defined as shell element.The thickness of block and polishing plate was larger,so the

关 键 词：硅片 化学机械抛光(CMP) 有限元分析 法向应力 

分 类 号：TN304[电子电信—物理电子学]