聚焦位置对光谱椭偏仪膜厚测量的影响  

Effects of Focusing Position on Film Thickness Measurement by Spectroscopic Ellipsometry

作　　者：季鹏 杨乐 陈鲁 李成敏 张嵩 Ji Peng;Yang Le;Chen Lu;Li Chengmin;Zhang Song(Skyverse Technology Co.,Ltd.,Shenzhen 518110,China)

机构地区：[1]中科飞测科技股份有限公司,广东深圳518110

出　　处：《半导体技术》2021年第10期819-823,共5页Semiconductor Technology

基　　金：深圳市科技计划资助项目(KQTD2016053116451329)。

摘　　要：膜厚测量是半导体芯片制备过程中的关键技术。介绍了工业级膜厚测量设备的工作原理和技术要求。以聚焦光谱椭偏仪为实验平台,在光学聚焦位置附近(±5μm范围),通过连续改变晶圆聚焦高度,定量测量了多个标准厚度热氧化硅薄膜样品的膜厚与多次测量的静态重复性指标,揭示了测量厚度对聚焦高度较强的依赖关系和静态重复性对聚焦高度变化的不敏感。根据实验数据,定量分析得出在1.3~1.5μm聚焦重复性条件下,宽谱椭偏仪可以达到的膜厚检测重复精度极限为0.01~0.012 nm。因此提高聚焦重复性是改进重复精度这一指标的关键因素。Film thickness measurement is a critical technology in the semiconductor chip fabrication process.The working principle and technical requirements of an industrial film thickness measurement device were introduced.With a focusing spectroscopic ellipsometer platform, the film thicknesses of thermal silicon oxide film samples with multiple standard thicknesses and static repeatability index of multiple measurements were quantitatively measured by continuously changing the focusing height of the wafer near the optical focusing position(±5 μm range).It reveals a strong dependence of the measurement thickness on the focusing height and the insensitivity of static repeatability to variations of the focusing height.Based on the experimental data, the quantitative analysis shows that under the condition of 1.3-1.5 μm focusing repeatability, the repeatability precision limit of the film thickness measurement by broad spectroscopic ellipsometry is up to 0.01-0.012 nm.Therefore, improving the focusing repeatability is the key to improve the repeatability precision.

关 键 词：半导体芯片 膜厚测量 光学仪器 聚焦 重复性 

分 类 号：O484.5[理学—固体物理] TH74[理学—物理]