Lou:
I've tried a number of etchants, including those below on Pt and Pd. Pt is
really hard to etch in anything.
Pd has a reasonable etch rate in aqua regia.
See "Etch Rates for Micromachining Processing--Part II" in JMEMS, Dec. 2003.
There are several copies online.
Any of these metals will etch a little bit in SF6 RIE (plasma with ion
bombardment), not due to chemical etching, but from sputtering.
    --Kirt Williams

----- Original Message -----
From: "Lou Chomas" 
To: 
Sent: Thursday, May 11, 2006 5:38 PM
Subject: [mems-talk] Platinum Group Metals


> Hi All,
>     I'm trying to select a platinum group metal (Pt, Pd, Rh, Ir, Os, Ru,
> etc.) for use in my device.  I was wondering if anyone had any information
> on the etch resistance of these materials to various etches.  In
> particular, I'd like to know if they can withstand hot phosphoric acid,
> HF, BOE, and SF6 RIE.  Any help or pointers to references would be greatly
> appreciated.
>
> Best,
> Lou