If I understand you then you have one gas for CF4 and one for O2. You can
order your gas already mixed in the bottle with CF4+6% Oxygen, then you can
run He in the other. Gas flow should be 40-60 sccm CF4/O2 and 100 sccm He.
The helium helps to keep the photoresist from burning and helps to make the
plasma uniform over the whole wafer surface. I hope this helps.

 Bob Henderson
----- Original Message -----
From: "alim polat" 
To: "General MEMS discussion" 
Sent: Thursday, February 07, 2008 7:09 AM
Subject: Re: [mems-talk] Dry etch to get patterned SiO2 hard mask


> It looks like only the PECVD machine has the gas pipe that He runs
> through. I haven't checked if I can run this pipe through RIE. What
> would be the recipe if I can run He through RIE machine. On RIE CF4
> looks like doesn't come with O2, but there is O2 gas pipe running
> through RIE. So I don't quite get CF4+O2 at 6% means. Does that mean I
> can run CF4 and O2 gases run in the chamber together?
> Alim Polat
> Linkoping University
> Sweden