[mems-talk] RIE Question

[Joseph Grogan]

Hi All,

We have a very old Plasmalab RIE in our facility that I tried using to 
etch a Si wafer patterned with 1813 resist. I used the following parameters:

02 flow rate: 5 sccm
SF6 flow rate: 20 sccm
pressure: 20 mT
power: 150 W
time: 1 hr

I had hoped to get a depth in the neighborhood of 60um or more with 
these settings (based on literature such as Williams' etch rates paper). 
Unfortunately, I only got around 4.5 um deep, and that was only in the 
center 2" of my 4" wafer. The outer 2" of my wafer was coated in an odd 
white chalky film that smudged off a little if I wiped it.

Does anyone have a guess as to what my problem is?

thanks,
Joe Grogan