Development of a compact spectral thickness measurement instrument for thin film

LIU Jiamin; TAO Ze; ZHANG Chuanwei; LIU Shiyuan

doi:10.7510/jgjs.issn.1001-3806.2016.04.003

In order to develop a compact instrument to measure the thickness of isotropic uniform thin films, applying a common normal incident path and thin-film interference principle, the film thickness was calculated inversely by fitting the measured reflectance spectrum with nonlinear optimization algorithm. The relative error between the thickness of a SiO2/Si thin film measured by the proposed instrument and that measured by the commercial ellipsometer was less than 0.5%, and the time for a single measurement was about 70ms. Experimental results show that the proposed instrument has advantages of insensitivity to measuring distance, concise light path, compact structure and excellent repeatability. The study has great significance for online measurement of thin film thickness.

Development of a compact spectral thickness measurement instrument for thin film

Corresponding author: ZHANG Chuanwei, chuanweizhang@hust.edu.cn;

1. State Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan 430074, China

Received Date: 2015-10-19

Accepted Date: 2015-10-27

Available Online: 2016-07-25

Abstract: In order to develop a compact instrument to measure the thickness of isotropic uniform thin films, applying a common normal incident path and thin-film interference principle, the film thickness was calculated inversely by fitting the measured reflectance spectrum with nonlinear optimization algorithm. The relative error between the thickness of a SiO2/Si thin film measured by the proposed instrument and that measured by the commercial ellipsometer was less than 0.5%, and the time for a single measurement was about 70ms. Experimental results show that the proposed instrument has advantages of insensitivity to measuring distance, concise light path, compact structure and excellent repeatability. The study has great significance for online measurement of thin film thickness.

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Reference (16)

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Development of a compact spectral thickness measurement instrument for thin film

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