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Applied Optics

Applied Optics


  • Editor: Joseph N. Mait
  • Vol. 48, Iss. 33 — Nov. 20, 2009
  • pp: 6432–6441

Measurement of buried undercut structures in microfluidic devices by laser fluorescent confocal microscopy

Shiguang Li, Jing Liu, Nam-Trung Nguyen, Zhong Ping Fang, and Soon Fatt Yoon  »View Author Affiliations

Applied Optics, Vol. 48, Issue 33, pp. 6432-6441 (2009)

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Measuring buried, undercut microstructures is a challenging task in metrology. These structures are usually characterized by measuring their cross sections after physically cutting the samples. This method is destructive and the obtained information is incomplete. The distortion due to cutting also affects the measurement accuracy. In this paper, we first apply the laser fluorescent confocal microscopy and intensity differentiation algorithm to obtain the complete three-dimensional profile of the buried, undercut structures in microfluidic devices, which are made by the soft lithography technique and bonded by the oxygen plasma method. The impact of material wettability and the refractive index (n) mismatch among the liquid, samples, cover layer, and objective on the measurement accuracy are experimentally investigated.

© 2009 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:
Image Processing

Original Manuscript: July 6, 2009
Revised Manuscript: October 12, 2009
Manuscript Accepted: October 21, 2009
Published: November 11, 2009

Shiguang Li, Jing Liu, Nam-Trung Nguyen, Zhong Ping Fang, and Soon Fatt Yoon, "Measurement of buried undercut structures in microfluidic devices by laser fluorescent confocal microscopy," Appl. Opt. 48, 6432-6441 (2009)

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