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Microsystem Technologies

, Volume 14, Issue 9–11, pp 1285–1290 | Cite as

Microlens array fabrication by backside exposure using Fraunhofer diffraction

  • In-Hyouk SongEmail author
  • Kyung-Nam Kang
  • Yoonyoung Jin
  • Daniel S.-W. Park
  • Pratul K. Ajmera
Technical Paper

Abstract

In UV-lithography, a gap between photoresist and UV-mask results in diffraction. Fresnel or near-field diffraction in thick positive and negative resists for microstructures resulting from a small gap in contact or proximity printing has been previously investigated. In this work, Fraunhofer or far-field diffraction is utilized to form microlens arrays. Backside-exposure of SU-8 resist through Pyrex 7740 transparent glass substrate is conducted. The exposure intensity profile on the interface between Pyrex 7740 glass wafer and negative SU-8 resist is modeled taking into account Fraunhofer diffraction for a circular aperture opening. The effects of varying applied UV-doses and aperture diameters on the formation of microlens arrays are described. The simulated surface profile shows a good agreement with the experimentally observed surface profiles of the microstructures. The paper demonstrates the ease with which a microlens array can be fabricated by backside exposure technique using Fraunhofer diffraction.

Keywords

Aperture Diameter Microlens Array Glass Wafer Structure Height Fraunhofer Diffraction 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgments

The authors would like to thank the Center for Advanced Microstructures and Devices (CAMD) for the use of the microfabrication facilities. Any opinions, findings, and conclusions or recommendations expressed here are solely those of the authors.

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Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • In-Hyouk Song
    • 1
    Email author
  • Kyung-Nam Kang
    • 2
  • Yoonyoung Jin
    • 3
  • Daniel S.-W. Park
    • 4
  • Pratul K. Ajmera
    • 2
  1. 1.Department of Physics EngineeringÉcole Polytechnique de MontréalMontréalCanada
  2. 2.Department of Electrical and Computer EngineeringLouisiana State UniversityBaton RougeUSA
  3. 3.Center for Advanced Microstructures and DevicesLouisiana State UniversityBaton RougeUSA
  4. 4.Center for BioModular Multi-scale SystemsLouisiana State UniversityBaton RougeUSA

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