Does anyone know if this is the same photo acid generator that is used in
HDMicrosystems 2720 series photodefinable polyimide?  I see this same
grey-black powder after I etch 2721 with an O2 plasma.  I have found that
the incorporation of 5-10% CF4 greatly reduces this residue but if your
process does not allow it, then I have also removed it after the RIE etch
with acetone in an ultrasound bath.  I have been trying to figure out what
this residue is for the past few months, because according to
HDMicrosystems literature, the 2720 series should easily etch in an O2
plasma.  I would greatly appreciate any comments from others that
understand the chemistry much better than I do.  Thanks.

> The residues you see are Antimony and antimonyoxide. It has a grey to
> black powdery appearance. Usually it can be removed using ultrasound.
> The antimony comes from the photo acid generator in the SU-8 which
> is an antimony salt.
>
> Jacques Jonsmann


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|                        N e l s   O s t r o m                            |
|                           ostrom@uiuc.edu                               |
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|                        Graduate Research Assistant                      |
|                        Optical Physics and Engineering                  |
|    oooO                Dept. of Electrical and Computer Engineering     |
|    (   )     Oooo                                                       |
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