Nonlinear phase error analysis of equivalent thickness in a white-light spectral interferometer  

作　　者：Tong Guo Qianwen Weng Bei Luo Jinping Chen Xing Fu Xiaotang Hu 

机构地区：[1]State Key Laboratory of Precision Measuring Technology and Instruments,Tianjin University

出　　处：《Nanotechnology and Precision Engineering》2019年第2期77-82,共6页纳米技术与精密工程（英文）

基　　金：the support of The National Key Research and Development Program of China(Grant No.2017YFF0107001);the 111 Project fund(Grant No.B07014)

摘　　要：A white light spectral interferometry based on a Linnik type system was established to accurately measure the thin film thickness through transparent medium.In practical work,the equivalent thickness of a beam splitter and the mismatch of the objective lens introduce nonlinear phase errors.Adding a transparent medium also increases the equivalent thickness.The simulation results showthat the equivalent thickness has a significant effect on thin film thickness measurements.Therefore,it is necessary to perform wavelength correction to provide a constant equivalent thickness for beamsplitters.In the experiments,some pieces of cover glasses as the transparent medium were added to the measured beam and then a standard thin film thickness of 1052.2±0.9 nm was tested through the transparent medium.The results demonstrate that our system has a nanometer-level accuracy for thin film thickness measurement through transparent medium with optical path compensation.A white light spectral interferometry based on a Linnik type system was established to accurately measure the thin film thickness through transparent medium. In practical work, the equivalent thickness of a beam splitter and the mismatch of the objective lens introduce nonlinear phase errors. Adding a transparent medium also increases the equivalent thickness. The simulation results show that the equivalent thickness has a significant effect on thin film thickness measurements. Therefore, it is necessary to perform wavelength correction to provide a constant equivalent thickness for beam splitters. In the experiments, some pieces of cover glasses as the transparent medium were added to the measured beam and then a standard thin film thickness of 1052.2±0.9 nm was tested through the transparent medium. The results demonstrate that our system has a nanometer-level accuracy for thin film thickness measurement through transparent medium with optical path compensation.

关 键 词：White light spectral interferometry Thin film thickness measurement Nonlinear phase Equivalent thickness Transparent medium 

分 类 号：O17[理学—数学]