Alim:

Do you have the ability to run Helium through one of your mass flow
controllers? If not you could purchase a bottle of CF4 + O2 at 6% which
might make the etch of SiO2 easier. Conditions of 40 sccm of CF4O2 a
pressure of around 1 torr power of 3-400 watts rf should yield a good
baseline for your etch process. If you use SF6 + He then 20 sccm SF6 + 100
sccm He,  pressure around 1 torr, power of around 300 watts should yield a
faster etch. Any standard positive photoresist at around 1.5 microns should
hold  up to either etch process with a selectivity of around 3-5:1. Good
luck. Bob Henderson
----- Original Message -----
From: "alim polat" 
To: 
Sent: Tuesday, February 05, 2008 2:17 AM
Subject: [mems-talk] Dry etch to get patterned SiO2 hard mask


> I have 200-400 nm thick SiO2 thin film grown using PECVD-RIE machine. Now
I
> need to etch the SiO2 thin film at the same machine to get patterned SiO2
> hard mask. I only have CF4 and SF6 gases in the machine. Could I get some
> advices on dry etching SiO2 to get patterned hard mask. Also I need what
> kind pf PR I should use on top of SiO2.