Microsystem Technologies

, Volume 12, Issue 10–11, pp 935–939 | Cite as

Defect-free wet etching through pyrex glass using Cr/Au mask

  • Francis E. H. Tay
  • Ciprian Iliescu
  • Ji Jing
  • Jianmin Miao
Technical paper


This paper reports the highest etch depth of annealed Pyrex glass achieved by wet etching in highly concentrated HF solution, using a low stress chromium–gold with assistance of photoresist as masking layer. The strategies to achieve that are: increasing the etch rate of glass and simultaneously increasing the resistance of Cr/Au mask in the etchant. By annealing the Pyrex glass and using a highly concentrated HF acid, a high etch rate can be obtained. Furthermore, a method to achieve a good resistance of the Cr/Au masking layer in the etching solution is to control the residual stress and to increase the thickness of Au deposition up to 1 μm. In addition, the presence of a hard baked photoresist can improve the etching performance. As a result, a 500-μm thick Pyrex glass wafer was etched through.


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Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Francis E. H. Tay
    • 1
    • 2
  • Ciprian Iliescu
    • 2
  • Ji Jing
    • 1
  • Jianmin Miao
    • 3
  1. 1.Department of Mechanical EngineeringNational University of SingaporeSingaporeSingapore
  2. 2.Institute of Bioengineering and NanotechnologySingaporeSingapore
  3. 3.Micromachines Center, School of Mechanical and Production EngineeringNanyang Technological UniversitySingaporeSingapore

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