You will probably have better luck using a downstream/rie type system at
very low pressures with helium cooling on the chuck. I would begin using
only oxygen at 20 sccm rie power at 25-40 watts and a pressure of 5-8 mtorr.
If that doesn't give you an anisotropic profile then I would look to add a
small amount of CHF3 to help passivate the sidewalls.

Bob Henderson

----- Original Message -----
From: "c c" 
To: 
Sent: Tuesday, December 09, 2008 8:01 AM
Subject: [mems-talk] RIE etch of photoresist


Hi,

I Want to etch photoresist wall, with angle near 90°, size near 20µm:

Is it possible to do that with a Plasma with O2-CF4-N2 800W?

What flows can i use for O2-CF4-N2?