I agree with Mike.  Try using a RIE or DRIE oxygen plasma, its easy and safe.
In a March 1701 RIE we would run 300-400mT of O2 at 300-400W.  Though I would
add that you might want to try a CF4 ~16-20% + O2 step for say 30 seconds for a
little more aggressive removal of material in addition to the oxygen etch.


>>> Mike Whitson  6/24/2010 11:17 AM >>>
The asher will eventually do the job, but you may have to let it run for a very
long time, and there's a good chance you will have to contend with problems
related to heating of your sample.  If you have access to it, oxygen RIE can be
much faster and more effective than a barrel asher.  I've used a bench-top ICP-
RIE to strip cross-linked PMMA with good success.  If you want to be extra
thorough, you can use piranha much more safely after the RIE has taken out most
of the organic material - piranha can be very violent if you give it a lot of
organic matter to oxidize at once.

Even if you don't have a specific oxygen RIE, many DRIE tools have an oxygen
cycle for chamber descumming which can also be used for organic stripping if
your facility's SOP allows.

Solvent-based strippers (acetone, NMP, etc.) won't help you on cross-linked
resists, don't bother with those.

-Mike