HI,

I did not do Ag etch before. but there is a good reference with several
Ag etch recipe. please see p.182-3 of "

Etching in microsystem technology / Michael Köhler ; translated by Antje
Wiegand

" -

TK7872.M3 K6413 1999

zeta
ucla


Martyn Gadsdon wrote:

> Hello,
>
> I am trying to make silver polarization gratings for optical spectrum,
> i.e. I am making thin silver wires about 100nm high and with a period
> of about 250nm. My method is as follows,
>
> I evaporate 100nm Ag onto a silica (or glass) substrate. Spin 150nm
> thickness of photoresist on top of this. Then I over expose and
> develop (using NaOH) the photoresist into a diffraction grating so
> that part of the silver is exposed. I think I have got this far sorted
> ok (though I am not sure if I am actually revealing the silver
> underneath the photoresist properly.
>
> My problem is in the next stage, I am then trying to etch the revealed
> silver using nitric acid. When I try to do this the silver that is
> exposed changes to a milky colour (and becomes transparent) and then
> stops dissolving no matter how long I attempt to etch for. The
> photoresist mask seems unaffected, but when I remove in it do not see
> any diffraction or polarization effects as expected.
>
> What am I doing wrong?! Or is there a easier way to do this e.g.
> better etch solution?
>
> Thanks
>
> Martyn Gadsdon