Use warm or hot aqua regia. It won't etch Si or SiO2, but does etch Pt.
Check for papers online regarding etch rates for micromachining...
    --Kirt Williams

----- Original Message -----
From: "Jeehwan Kim" 
To: 
Sent: Thursday, June 22, 2006 1:51 PM
Subject: [mems-talk] Pt etchant


> Dear colleagues,
>
> I will use the Pt to protect my Si wafer surface for anodization. Is there
> any one who has a recipe for removing Pt without attacking Si surface?