Hello Tony Li,
We have two brand new ICP etchers. I have just been experimenting on them
for 6 months, but we are getting quite good results. We were recommended to
use mixtures of C4F8 and CH4 (or H2). I think the CH4 are improving the
selectivity (if I remember correct).
-----Original Message-----
From: Tony Li
To: General MEMS discussion
Cc: Storås Preben
Sent: 26.01.2004 18:28
Subject: Re: [mems-talk] problems with RIE grass

Hi Storas: are you using CH4 instead of CF4 for SiO2 etch? Is it a typo?
----- Original Message -----
From: "Storås Preben" 
To: 
Sent: Sunday, January 25, 2004 10:26 AM
Subject: [mems-talk] problems with RIE grass


> Hello Jiaping Yue,
>
> Could there be a problem with a sputtering effect from the substrate
holder?
>
> I am doing DRIE on 5 x 5 mm areas with the Bosch (C4F8) and Cryo
process
> (SF6 + O2). When etching with the Cryo process at 4.0 Pa I got a lot
of
> grass, but at 2.8 Pa the surface was nice. It was similar with the
Bosch
> process. Thought this might not be helpfull for your SiO2 etch.
>
> Have you tried reduce bias or change pressure?
>
>  I am also doing SiO2 RIE on an AMS200 etcher (C4F8 + CH4), but I had
no
> problems with grass on this process.
>
>
> Best luck with your grass fighting
>
> Preben Storas
>