全反射式宽光谱成像椭偏仪

摘要

We developed a broadband spectroscopic imaging ellipsometer, which is free of chromatic aberration, by using an all-reflective focusing optical structure with special polarization control. A calibration method by measuring multiple standard samples was employed in the system calibration procedure. By applying the obtained system calibration parameters, we can determine the test sample’s spatial distributions of ellipsometric anglesψ andσ, and the film thickness after the imaging ellipsometric analysis. To test the accuracy of our home-made imaging ellipsometer, we have measured the SiO2/Si samples with the thicknesses of 3 nm~300 nm at multiple wavelengths between 200 nm and 1 000 nm. The experimental result shows that the SiO2film thickness can be determined within the maximum relative measurement error of 6%.%本论文采用全反射式光学聚焦结构，通过独特的偏振控制技术，实现宽光谱、无色差成像椭偏仪的研制。在系统校准过程中采用多样品校准方法，利用校准得到的系统参数对待测样品进行成像椭偏分析，确定样品椭偏角ψ和σ及薄膜厚度的空间分布。为测试自制成像椭偏仪的准确性，本文对3 nm~300 nm的SiO2/Si样品在200 nm~1000 nm内多波长下进行成像椭偏测量。实验结果表明，SiO2薄膜厚度最大相对测量误差小于6%。