A Wet Etch Release Method for Silicon Microelectromechanical Systems (MEMS) Using Polystyrene Microspheres for Improved Yield

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Description:

One of the final steps in fabricating microelectromechanical devices often involves a liquid etch release process. Capillary forces during the liquid evaporation stage after the wet etch process can pull two surfaces together resulting in adhesion of suspended microstructures to the supporting substrate. This release related adhesion can greatly reduce yields. In this report, a wet etch release method that uses polystyrene microspheres in the final rinse liquid is investigated. The polystyrene microspheres act as physical barriers between the substrate and suspended microstructures during the final liquid evaporation phase. A plasma ashing process is utilized to completely remove the polystyrene microspheres from the microstructure surfaces. Using this process, release yields > 90% were achieved. It is found that the surface roughness of gold surfaces increases while that of the silicon is reduced due to a thin oxide that grows on the silicon surface during the plasma process.

Creator(s): Mantiziba, Fadziso
Creation Date: May 2004
Partner(s):
UNT Libraries
Collection(s):
UNT Theses and Dissertations
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Total Uses: 172
Past 30 days: 7
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Publisher Info:
Publisher Name: University of North Texas
Place of Publication: Denton, Texas
Date(s):
  • Creation: May 2004
  • Digitized: January 9, 2008
Description:

One of the final steps in fabricating microelectromechanical devices often involves a liquid etch release process. Capillary forces during the liquid evaporation stage after the wet etch process can pull two surfaces together resulting in adhesion of suspended microstructures to the supporting substrate. This release related adhesion can greatly reduce yields. In this report, a wet etch release method that uses polystyrene microspheres in the final rinse liquid is investigated. The polystyrene microspheres act as physical barriers between the substrate and suspended microstructures during the final liquid evaporation phase. A plasma ashing process is utilized to completely remove the polystyrene microspheres from the microstructure surfaces. Using this process, release yields > 90% were achieved. It is found that the surface roughness of gold surfaces increases while that of the silicon is reduced due to a thin oxide that grows on the silicon surface during the plasma process.

Degree:
Level: Master's
Note:

Problem in Lieu of Thesis

Language(s):
Subject(s):
Keyword(s): MEMS | etch release | polystyrene microspheres | plasma ashing | anti-stiction
Contributor(s):
Partner:
UNT Libraries
Collection:
UNT Theses and Dissertations
Identifier:
  • ARK: ark:/67531/metadc4457
Resource Type: Thesis or Dissertation
Format: Text
Rights:
Access: Use restricted to UNT Community
License: Copyright
Holder: Mantiziba, Fadziso
Statement: Copyright is held by the author, unless otherwise noted. All rights reserved.