Thanks, I'll look into it.

Just to clarify, we do need some photoresist for the optical lithography
(defining the places where the holes go), not just as protective layer. But of
course making double layers is in principle fine.


Am Sonntag, 7. Mai 2017, 03:06:28 CEST schrieb Andrew Sarangan:
> You may want to try ProTek PSB coating by Brewer Science. It can be used in
> place of a photoresist. I have tried this and found it to be a good
> solution. However, it did not survive long KOH etching, but it might be ok
> for shorter etches.
>
>
> On Sat, May 6, 2017 at 7:42 PM, Andreas K. Huettel <
>
> andreas.huettel@physik.uni-regensburg.de> wrote:
> > Dear all,
> >
> > we need to etch deep holes into a Si wafer (with a 500nm surface oxide)
> > that
> > already has sensitive Nb structures on top.
> >
> > The etching alone works mostly fine with first RIE through the oxide and
> > then
> > hot KOH. However, the KOH also dissolves our photoresist and then attacks
> > the
> > niobium.
> >
> > We already tried placing a baked-out PMMA layer between niobium and
> > photoresist, but that didn't help too much.
> >
> > Do you have any advice for this?
> > Are there any photoresists around that are KOH-stable?
> > What other protective could be used that later are easily removed?
> >
> > Best,
> > Andreas
> >
> > --
> > PD Dr. Andreas K. Huettel
> > Institute for Experimental and Applied Physics
> > University of Regensburg
> > 93040 Regensburg
> > Germany
> >
> > tel. +49 151 241 67748 (mobile)
> > tel. +49 941 943 1618 (office)
> > fax +49 941 943 1670
> > e-mail andreas.huettel@ur.de
> > http://www.akhuettel.de/
> > http://www.physik.uni-r.de/forschung/huettel/
> > _______________________________________________
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--
PD Dr. Andreas K. Hüttel
Institute for Experimental and Applied Physics
University of Regensburg
93040 Regensburg
Germany

tel. +49 941 943 1618 (office)
tel. +49 151 241 67748 (mobile)
e-mail andreas.huettel@ur.de
http://www.akhuettel.de/
http://www.physik.uni-r.de/forschung/huettel/

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