作者：张晓东, 韩志国, 李锁印, 梁法国
作者单位：中国电子科技集团公司第十三研究所, 河北 石家庄 050051
关键词：光谱型椭偏仪;等效结构模型;四相结构模型;表层分子吸附
摘要：
针对膜厚标准样片的高精度测量问题，基于光谱型椭偏仪测量系统，提出对膜厚标准样片逐层分析的方法。利用相应的匹配算法，对比硅上二氧化硅模厚标准样片的等效结构模型和四相结构模型，实现对薄膜样片的厚度表征和椭偏分析。其次，通过对样片进行为期12周的测量考核，完成对薄膜样片表层分子吸附机理的分析。实验结果表明：针对研制的标称值为2~1 000 nm硅上二氧化硅膜厚标准样片，中间层的厚度存在先递减后递增的趋势。其中，在标称值为50~500 nm范围内，等效结构模型与四相结构模型测量结果的绝对误差在±0.2 nm以内，因此，可以采用等效结构模型的方法开展仪器的校准工作。另外，提出通过加热实现对标准样片解吸附的方案，有效解决超薄膜样片的储存问题。
The ellipsometry analysis of the standard sample on nano-scale film thickness
ZHANG Xiaodong, HAN Zhiguo, LI Suoyin, LIANG Faguo
The 13th Institute of CETC, Shijiazhuang 050051, China
Abstract: Aiming at the high-precision measurement of film thickness standard samples, a layer-by-layer analysis method for film thickness standard samples was proposed,based on the spectral ellipsometer measurement system.By using the corresponding matching algorithm, the four-phase structure model and equivalent structure model of the standard sample of SiO2 film thickness were compared to realize the thickness characterization and ellipsometry of the film samples.Secondly,through the 12-week measurement and evaluation of the samples, the analysis of the molecular adsorption mechanism of the film samples was completed.The experimental results show that for the developed SiO2/Si standard sample of 2 nm-1 000 nm, the thickness of the middle layer tends to decrease first and then increase.Among them, the absolute error between the equivalent structural model and the four-phase structural model is within ±0.2 nm for the standard sample from 50 nm to 500 nm.Therefore, the calibration of the instrument can be carried out using the equivalent structural model.In addition, a solution for desorbing standard samples by heating has been proposed, which effectively solves the problem of storage of ultra-thin film samples.
Keywords: spectral ellipsometer;equivalent structure model;four-phase structure model;surface molecular adsorption
2019, 45(8):14-18 收稿日期: 2018-07-14;收到修改稿日期: 2018-08-25
基金项目:
作者简介: 张晓东(1992-),男,山东菏泽市人,硕士,主要从事微纳尺寸标准样片的研制与定标研究
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