Hi, Terry,
I had some similar experience before. What I did is put AZ PR under Cr layer,
and then using SU-8 to form the electroplating mold. However the OmniCoat of
SU-8 seems to penertrate the Cr layer and mix with AZ PR. The NR7 series with
SU-8 have the similar problems.

I am not sure about whether other PRs photoresist can work well. But I am not
optimistic about this method.

I used Transene Cr etchant, it has very good selectivity between Cr and Cu.

Good luck.
J.J. Wang

Terry Zhu  wrote: Dear All,

  I have a structure off Au/Cr with plated Copper on top. I am trying to find a
way etcing the Au/Cr (seed layer). I can either etch the Au/Cr after Cu plated
or use lift-off process. However, I am concerned with etching Au/Cr after Cu
plated without affect Cu. If I put resist first before seed layer of Au/Cr, Then
pattern it again for Cu plating, I am not sure if I can lift off the seed layer.
Can anyone give some ideas for either situations? What are the etchant(s) that
is/are better for the processes? Thanks.

  Terry Zhu