What recipe did you use?

Rick


-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of
morad massalha
Sent: Tuesday, September 21, 2010 12:03 AM
To: [email protected]
Subject: [mems-talk] Selective Poly etch for P+

I have read about this mix that etch P+ 1E18 and stop on P- (1E14).  I
tried this
while etching a silicon wafer with EPI. I took silicon and I put it in
the mix for 5
min. The result was that wafer etched on both sides with same thickness.
Maybe
from P+ etched more about 30%, but I did not get any selectivity between
P- and
P+.  Can somebody explain this please.