Tong Guo, Qianwen Weng, Bei Luo, Jinping Chen, Xing Fu, Xiaotang Hu
{"title":"Nonlinear phase error analysis of equivalent thickness in a white-light spectral interferometer","authors":"Tong Guo, Qianwen Weng, Bei Luo, Jinping Chen, Xing Fu, Xiaotang Hu","doi":"10.1016/j.npe.2019.07.003","DOIUrl":null,"url":null,"abstract":"<div><p>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.</p></div>","PeriodicalId":87330,"journal":{"name":"Nanotechnology and Precision Engineering","volume":"2 2","pages":"Pages 77-82"},"PeriodicalIF":0.0000,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.npe.2019.07.003","citationCount":"1","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Nanotechnology and Precision Engineering","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2589554019300224","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 1
Abstract
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.