Hi,

I am trying to oxidize 20nm thick aluminum in the RIE. Aluminum is deposited
by the e-beam evaporator. I have 250nm of e-beam resist under the aluminum
layer. each time I try my samples under O2 plasma, my aluminum layer gets
damaged.

My RIE process conditions are Power=300Watts, Pressure = 250mTorr, Base
Pressure = 60mTorr, O2 flow = 15 or 20sccm, RF Plasma Time = 180 or 600
seconds. I tried with both flow rates and both RF plasma times and I got no
results.

I noticed that my wafer was getting hot after the RIE process in spite of
having the chiller switched on. Also I tried once with a silicon wafer with
200nm Aluminum (with no e-beam resist) and the aluminum just peeled off from
the surface for the same recipe.

Can anyone tell me about optimum recipe to achieve this without destroying
my aluminum layer and the underlying e-beam resist? Thanks in anticipation.

Regards,
Kapil

Graduate Student
University of Cincinnati, OH