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Proceedings Paper

Optical inspection of noncooperative copper surface structures using multi- and hyperspectral acquisition systems
Author(s): Markus Wrieden; Andreas Breitbarth; Manuel Zimmermann; Jörg Schambach; Maik Rosenberger; Gunther Notni
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Paper Abstract

In order to enhance the efficiency of quality inspection of Direct Copper Bonded (DCB) structures an optical inspection using a 3D measuring system is conceivable. However, it is a challenging task to use 3D optical measurement techniques for diffuse reflective copper surfaces. This work deals with the optical detection of defects of the copper surface, using multi- and hyperspectral acquisition devices. Over a broad spectral range from the visual spectrum to the short-wave infrared (400 nm - 1700 nm) it is analysed which wavelengths provide good contrast ratios for the detection of flaws. For the inspection of the sample back side, the push-broom imager, operating in the VIS and NIR range (400 nm - 1000 nm), provides the best contrast ratio. An outstanding contrast is reached around 400 nm. Deposited particles on the front side of the DCB substrates are best detected by the filter wheel camera, which is sensitive in the visual and near infrared range. Outstanding contrast is reached with wavelengths around 640 nm. After evaluating the standard deviations of the gray values, it can be shown that defects differ clearly from flawless substrate areas under investigation with light of wavelengths 577 nm, 640 nm and 950 nm. Furthermore, the comparison between certain pixel spectra confirms that significant differences appear at the same three wavelengths. Regarding an automated inspection of defects, it is advisable to shift the pattern projection for the 3D correspondence analysis to the spectral ranges mentioned.

Paper Details

Date Published: 21 June 2019
PDF: 11 pages
Proc. SPIE 11061, Automated Visual Inspection and Machine Vision III, 1106106 (21 June 2019); doi: 10.1117/12.2525734
Show Author Affiliations
Markus Wrieden, Technische Univ. Ilmenau (Germany)
Andreas Breitbarth, Technische Univ. Ilmenau (Germany)
Manuel Zimmermann, GÖPEL electronic GmbH (Germany)
Jörg Schambach, GÖPEL electronic GmbH (Germany)
Maik Rosenberger, Technische Univ. Ilmenau (Germany)
Gunther Notni, Technische Univ. Ilmenau (Germany)
Fraunhofer-Institut für Angewandte Optik und Feinmechanik IOF (Germany)

Published in SPIE Proceedings Vol. 11061:
Automated Visual Inspection and Machine Vision III
Jürgen Beyerer; Fernando Puente León, Editor(s)

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