Hi,

Can you elaborate on the the problem you are experiencing with
electroplating?  Is it that the surface gets tarnished after a while?  I
have had a few problems with electroplating of copper because it is prone
to surface oxidation so easily.  The best protection would be to carefully
wash it once the deposition is done. First step after deposition is to
immerse the wafer in a bucket of fresh deionzed water.  Then I used to
make a bath of 1M H2SO4 and dipped my whole wafer in that solution.
Having placed it in that bath for a few minutes, take it out, wash it very
rapidly with ethanol (200 proof) and finish with a bath of deionized
water.  The final step would be to dry it very thoroughly with N2 gas.
Hope this helps.  Once again, the method we tried was quite crude and
rudimentary in nature.  It seemed to have solved the problem with
post-plating oxidation, but we were not quite sure how it did that.  My
guess would be there are some dangling bonds on the surface after
deposition, and once you immerse it in H2SO4, somehow those bonds are
either washed away, or a thin surface passivation layer is formed which
prevents oxidation.

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Rajib Ahmed
347 Hopeman Engineering Building
Department of Electrical and Computer Engineering
University of Rochester
Rochester, NY 14627-0167
Email:rajib@ece.rochester.edu
Phone#:(585)275-8093
Fax#:(585)273-4919
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