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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 16, Iss. 6 — Mar. 17, 2008
  • pp: 4001–4014

Three dimensional sidewall measurements by laser fluorescent confocal microscopy

Shiguang Li, Zhiguang Xu, Ivan Reading, Soon Fatt Yoon, Zhong Ping Fang, and Jianhong Zhao  »View Author Affiliations

Optics Express, Vol. 16, Issue 6, pp. 4001-4014 (2008)

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Precise three dimensional (3D) profile measurements of vertical sidewalls of concave micro-structures are impossible by conventional profiling techniques. This paper introduces a simple technique which can obtain 3D sidewall geometry by means of laser fluorescent confocal microscopy and an intensity gradient algorithm. The measurement principle is: when a concave micro-structure is filled up with fluorescent solution, the position where the maximum intensity variation lays represents the profile of the micro-structure in the fluorescent 3D volume image. The physical essence behind this measurement principle is analyzed in this paper in detail. The strengths and limitations of this technique are studied by experiments or by illustrations. The factors that are able to improve the measurement accuracy are discussed. This technique has demonstrated the capability for measuring of 3D geometry of various concave features, such as vertical, buried and other micro channels with sub-µm (RMS) measurement accuracy and repeatability.

© 2008 Optical Society of America

OCIS Codes
(100.5010) Image processing : Pattern recognition
(100.6890) Image processing : Three-dimensional image processing
(120.0120) Instrumentation, measurement, and metrology : Instrumentation, measurement, and metrology
(120.2830) Instrumentation, measurement, and metrology : Height measurements
(120.6650) Instrumentation, measurement, and metrology : Surface measurements, figure

ToC Category:
Instrumentation, Measurement, and Metrology

Original Manuscript: November 16, 2007
Revised Manuscript: February 10, 2008
Manuscript Accepted: February 26, 2008
Published: March 11, 2008

Virtual Issues
Vol. 3, Iss. 4 Virtual Journal for Biomedical Optics

Shiguang Li, Zhiguang Xu, Ivan Reading, Soon Fatt Yoon, Zhong Ping Fang, and Jianhong Zhao, "Three dimensional sidewall measurements by laser fluorescent confocal microscopy," Opt. Express 16, 4001-4014 (2008)

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