Hi Nidhi,

You can use Argon and do sort of Ion Beam Milling using the sputtering or
RIE system. You may need to lower the pressure to get a beam of Ar ions.
Better you do some etching tests on a test sample. After wet etching of Au
you will need to retain the photo resist since it can do milling of almost
anything exposed to the beam.

Samadhan


----- Original Message -----
From: "nidhi maheshwari" 
To: 
Sent: Friday, July 31, 2009 10:22 AM
Subject: [?? Probable Spam] [mems-talk] etching of Cr/Pt/Au stack


> Dear All,
>
> I have a stack of chromium/platinum/gold (20nm/20nm/200nm) onto glass.
> I need to pattern and etch it to make electrodes. Process requirement
> is such that I can not use lift-off process for the same. Can anyone
> please suggest a method by which I can etch Platinum without affecting
> gold on top of it. As far as I know aqua regia etches gold very fast,
> so I can not use that for etching platinum. For dry etching we have
> CF4 and SF6 gases available. Can these be used for etching platinum?
> Any suggestions on the recipe for dry etching using these gases would
> be very helpful.
>
> Thanks and regards,
>
> Nidhi