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http://dx.doi.org/10.6117/kmeps.2019.26.4.141

Sensitivity Improvement of Shadow Moiré Technique Using LED Light and Deformation Measurement of Electronic Substrate  

Yang, Heeju (School of Mechanical Engineering, Chungbuk National University)
Joo, Jinwon (School of Mechanical Engineering, Chungbuk National University)
Publication Information
Journal of the Microelectronics and Packaging Society / v.26, no.4, 2019 , pp. 141-148 More about this Journal
Abstract
Electronic substrates used in a mobile device is composed of various materials, and when the temperature is changed during manufacturing or operating, thermal deformation and stress concentration occur due to the difference in thermal expansion coefficient of each material. The shadow moiré technique is a non-contact optical method that measures shape or out-of-plane displacement over the entire area, but it is necessary to overcome the Talbot effect for high sensitivity applications. In this paper, LED light sources of various wavelengths was used to overcome the Talbot effect caused in the shadow moiré technique. By using the phase shift method, an experimental method to retain the measurement sensitivity within 10 ㎛/fringe was proposed and evaluated, and this method is applied to the thermal deformation measurement of the mobile electronic substrate. In the case of using white light, there were several areas that could not be measured due to the Talbot effect, but in the case of using blue LED light, it was shown that a precise moiré pattern with a sensitivity of 6.25 ㎛/fringe could be obtained in most areas.
Keywords
Shadow $moir{\acute{e}}$; Phase shift; Talbot effect; Blue LED; Talbot distance;
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Times Cited By KSCI : 2  (Citation Analysis)
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1 D. post, B. Han, and P. Ifju, "High Sensitivity moire: Experimental Analysis for Mechanics and Materials", Springer Science & Business Media, pp.119-130, New York (1994).
2 H. Takasaki, "Moire Topography", Applied Optics, 9, 1467 (1970).   DOI
3 Y. J. Kang, W. J. Ryu, and Y. K. Kwon, A Study on the Improvement of Accurasy of Surface Measurement in the Phase-Shifting Shadow Moire Method", J. of KSPE., 15(10), 96 (1998).
4 Y. Guo, "Applications of shadow moire method in determination of thermal deformations in electronic packaging", Proc. SEM Spring Conference on Experimental Mechanics, Grand Rapids, 702 (1995).
5 S. M. Lee, and Y. Y. Earmme, "A Study on the Measurement of PWB Warpage Using Shadow Moire", Proc. KSME 2002 Meeting for Material & Fracture, 146 (2002).
6 D. S. Lee, and J. W. Joo, "Sensitivity Enhancement of Shadow Moire Technique for Warpage Measurement of Electronic Packages", J. Microelectron. Packag. Soc., 22(3), 57 (2015).   DOI
7 H. G. Yang, and J. W. Joo, "Deformation Measurement of Electronic Components in Mobile Device Using High Sensitivity Shadow Moire Technique", J. Microelectron. Packag. Soc., 24(1), 57 (2017).   DOI
8 H. Talbot, "On Facts Relating to Optical Science", Phil. Mag., 9, 401 (1836).
9 A. J. Durelli, and V. J. Parks, "Moire analysis of Strain", Prectice-Hall, Englewood Cliffs (1970).
10 E. Keren, and O. Kafri, "Diffraction Effects in Moire Deflectometry", J. Optical Society of America A, 2(2), 111 (1985).   DOI
11 M. Testorf, J. Jahns, N. A. Khilo, and A. M. Goncharenko, "Talbot effect for oblique angle of light propagation", Optics Commutications, 129, 167 (1996).   DOI