Someone here suggested O2 plasma followed by an alkaline wet clean. I
have not tried that yet, but I have found that C-F polymer residues
are very difficult to remove. We had some stubborn residue from CHF3
plasma. The samples were sent to Dupont Electronics because they have
some advanced cleaning products for etch residues, and even they were
not successful in removing the residue.  Best strategy is to avoid the
C-F buildup in the first place. Have you tried SF6 plasma? That should
not leave a stubborn residue.


On Tue, Jul 1, 2008 at 10:40 AM, Serena Eley  wrote:
> 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