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Proceedings Paper

Thick film geometric parameters measurement by white light interferometry
Author(s): Long Ma; Tong Guo; Fang Yuan; Jian Zhao; Xing Fu; Xiaotang Hu
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Paper Abstract

White light interferometry has been widely used in 3D profile mapping during the past two decades. However, it has a shortcoming when the measured structure is coated with transparent film. A new algorithm based on the combination of white light interferometry and image segmentation technology for measuring the thick transparent film is presented in this paper. The new algorithm can derive the surface topography of the upper and the lower surfaces as well as the thickness of the thick film simultaneously. The system equips Mirau objectives controlled by a high precision piezoelectric transducer to perform the vertical scanning. When the film is thick enough, the extracted interferogram will have two separate sets of waveform or two independent zero-order-OPDs (optical path difference). Then a dynamic threshold setting process is achieved by the Otsu's method which is originally used in image segmentation. A comparison of a variety of coherent peak detecting algorithms is firstly given in this paper, followed by a brief introduction of Otsu's method. After the computer simulation testing, a film thickness standard is measured to illustrate the capabilities of the new algorithm.

Paper Details

Date Published: 1 December 2009
PDF: 9 pages
Proc. SPIE 7507, 2009 International Conference on Optical Instruments and Technology: Optical Trapping and Microscopic Imaging, 75070G (1 December 2009); doi: 10.1117/12.837575
Show Author Affiliations
Long Ma, Tianjin Univ. (China)
Tong Guo, Tianjin Univ. (China)
Fang Yuan, Tianjin Univ. (China)
Jian Zhao, Tianjin Univ. (China)
Xing Fu, Tianjin Univ. (China)
Xiaotang Hu, Tianjin Univ. (China)

Published in SPIE Proceedings Vol. 7507:
2009 International Conference on Optical Instruments and Technology: Optical Trapping and Microscopic Imaging
Xiaocong Yuan; Yinmei Li; Arthur Chiou; Min Gu; Dennis Matthews; Colin Sheppard, Editor(s)

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