蓝宝石衬底损伤层厚度和折射率的椭偏测量  

Ellipsometric measurement of subsurface damaged layer thickness and refractive index of sapphire substrates

作　　者：崔长彩 李慧慧 陈希 周志豪 胡中伟 Cui Changcai;Li Huihui;Chen Xi;Zhou Zhihao;Hu Zhongwei(Institute of Manufacturing Engineering,Huaqiao University,Xiamen 361021,China;Quanzhou Sanan Semiconductor Technology Co.,Ltd.,Quanzhou 362300,China)

机构地区：[1]华侨大学制造工程研究院,厦门3361021 [2]泉州三安半导体科技有限公司晶圆生产部,泉州362300

出　　处：《仪器仪表学报》2023年第7期37-43,共7页Chinese Journal of Scientific Instrument

基　　金：国家自然科学基金面上项目(52275531)资助。

摘　　要：为了定量测量蓝宝石衬底在化学机械抛光过程中产生的损伤层厚度d和折射率n,提出了一种光谱椭偏测量法。首先,测量蓝宝石衬底反射光谱(波长范围:250~1650 nm)偏振态的改变量(即振幅比和相位差);然后,通过光学建模和测量数据反演,获得损伤层d和n。实验研究了Al_(2)O_(3)和SiO_(2)两种磨料加工蓝宝石衬底损伤层d和n的变化趋势,前者d呈现波动趋势且最小值(约1.4 nm)出现在40 min左右,后者d持续下降,在20 min接近1 nm;二者损伤层n均小于蓝宝石晶体n。另外,实验和仿真分析结果表明相位差与厚度变化趋势一致,因无需建模反演,可作为快速表征损伤层d变化趋势的参量。总之,所提方法作为光学无损测量模式,适用于加工过程监测。To quantitatively measure the thickness d and refractive index n of the damage layer on sapphire substrate produced during chemical mechanical polishing,a spectral ellipsometric method is proposed.First,the change of spectral polarization state(i.e.,amplitudes ratio and phases difference)of light(from 250 to 1650 nm)reflected on sapphire substrate is measured.Then,the thickness and refractive index of damaged layer are extracted by optical modeling and inversion of measured data.The d and n of substrates polished by Al_(2)O_(3)and SiO_(2)abrasives are measured.The d of the former fluctuates with the better result about 1.4 nm after 40 min,and the latter continues decreasing with the better result 1 nm after 20 min.The n produced by two abrasives is both smaller than that of sapphire crystal.Meanwhile,the experiment and simulation analysis indicate that the change of phase difference is similar with d,which can be used to quickly evaluate the change of damage layer thickness because of no requirements for modelling and inversion.Therefore,the proposed method can be utilized to monitor the machining process as a nondestructive optical way.

关 键 词：光谱椭偏 蓝宝石衬底 损伤层 厚度 折射率 

分 类 号：TH74[机械工程—光学工程]