Measurement of buried undercut structures in microfluidic devices by laser fluorescent confocal microscopy
Fang, Zhong Ping
Yoon, Soon Fatt
Date of Issue2009
School of Electrical and Electronic Engineering
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. This paper was published in Applied Optics and is made available as an electronic reprint (preprint) with permission of Optical Society of America. The paper can be found at DOI: [http://dx.doi.org/10.1364/AO.48.006432]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.