[mems-talk] Shear strength of gold on SU-8

[Yue Mun Pun, Jeffrey]

Hi all,
I am trying to fabricate a device which uses an in-plane two-arm cantilever to rip apart a thin 100nm thick Gold bridge, which is evaporated onto the SU-8 cantilever.  This gold bridge stretches between the cantilever and another platform also made of SU-8.

I have read that a thin film of gold (of thickness 300nm) has peak tensile stress of 300MPa and experiences a strain of 0.05 before it breaks.  So the SU-8 cantilever needs to exert such a force on the Gold bridge to break it.  

Since the gold also sits on the SU-8 and might be sheared off the SU-8 as the cantilever moves laterally, I would like to ask whether anyone has any information on the bond shear strength of Gold on SU-8 (I have read that the bond pull strength of Gold on SU-8 is 4.8MPa, but I would like to know what the bond shear strength is).

 

Mr. Jeffrey Mun Pun YUE
余文彬
Division of Bioengineering
Block E3, #05-18, Nanobioanalytics Lab
9 Engineering Drive 1
National University of Singapore
Singapore 117576
Tel: (65) 65165985, Fax: (65) 68723069
E-mail:  g0500396 at nus.edu.sg
Website:  http://www.bioeng.nus.edu.sg/people/trau/Lab_index.htm