Hi Xiaojing, are you using CF4 and CHF3 without oxygen mixed in?  I have had
difficult to remove polymers form using both CF4 and CHF3 while etching
SiO2.  Can you reduce the selectivity to the PMMA a little bit and add some
oxygen to the etch?  I have also had some success using Shipley PRX solution
to remove the etch residue.  PRX does etch SiO2 very slowly but didn't
matter on my application.

Good Luck,

Scott
----- Original Message -----
From: "Xiaojing Zou" 
To: "General MEMS discussion" 
Sent: Tuesday, August 15, 2006 4:35 PM
Subject: [mems-talk] How to remove the PMMA etching residue.


> Hi:
>
>    I did some CF4 and CHF3 etching SiO2 using PMMA as mask. But I found
> that there is alway something left around the etched SiO2.  Does anybody
> have these kinda experience about removal of these stuff ?? (It cannot be
> removed by acetone)