Hi,

I used AZ5214 PR as a mask for CF4 RIE (47 sccm, 35mtorr, 90W).  I etched
for 6 min.  After removing the PR using nanoremover PG and IPA, there
remains about 10nm of residue that I can't remove.  I've tried hot
nanoremover, long sonication sessions in nanoremover, sonication in acetone,
DCM, O2 ash (300W, up to 10 min), and O2 RIE (20 sccm, 100W, up to 3 min).

Any suggestions for removing this residue? (Btw, I have a thin Ti capping
layer on Nb.  So, the residue is on oxidized Ti).

Thanks, Serena