Measuring film thickness with Dual-laser imaging method

In order to realize the online thickness measurement of thin films, an automatic film thickness measuring system was established, and its optical design, mechanical structure design, as well as the analysis and evaluation of the optical aberration based on the software of ZEMAX were researched. Proj...

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Bibliographic Details
Published inJournal of intelligent & fuzzy systems Vol. 34; no. 2; pp. 1153 - 1159
Main Authors Ma, Guolu, Liu, Lixian, Yang, Guiyang, Wang, Chen, Zhao, Bin
Format Journal Article
LanguageEnglish
Published Amsterdam IOS Press BV 01.01.2018
Subjects
Aberration
Film thickness
Laser beams
On-line systems
Optical design
Spots
Thickness measurement
Thin films
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Summary:In order to realize the online thickness measurement of thin films, an automatic film thickness measuring system was established, and its optical design, mechanical structure design, as well as the analysis and evaluation of the optical aberration based on the software of ZEMAX were researched. Project two laser beams vertically onto the same position of the film respectively from upper and lower side there will be two round spots on the film surfaces, image the two spots onto the image detector the film thickness can be got according to the relationship between the measured film thickness and the orthocenters of the upper and lower imaging spots. During the calibrating experiment, a nonlinear correction method was proposed. Experimental results indicated that the measurement precision is±1 μm. After a period time of three months online working, the system was proven to have the characteristics of good stabilization, high precision and convenient maintenance.
ISSN:1064-1246
1875-8967
DOI:10.3233/JIFS-169409