Since you're making a four-probe measurent, the dimensions of the metal
contacts are probably on the order of a millimeter.
This is large enough for shadow masking:
1. Make a mask from a thin sheet of material with holes where you want the
pad.
2. Firmly clip the mask to the organic substrate. It is critical that there
not be a gap between the shadow mask and the substrate. And you don't want
it to shift during deposition.
3. Evaporate or sputter metal.
4. Remove mask and you're done.

The hardest part is making the shadow mask. You may get useful results with
pinholes in piece of foil or drilled holes in sheet metal.
For more-complex shapes, I've used DRIE to make patterns in a silicon wafer.

    --Kirt Williams

----- Original Message -----
From: "jpt sharma" 
To: 
Sent: Wednesday, October 04, 2006 5:19 PM
Subject: [mems-talk] Electrical contact on organic samples


> Hi Guys
>  I am trying to make an electrical contacts (four probe measurent) on
> organic samples. I am thinking to make chips with Pt and use FIB to  make
> electrical contact. I can't use the lithography because the  organic
> samples dissolve on Acetone.
>  anyone has better idea?
>  Hope to hear from you
>  Thanks
>  JP
>
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