Hi,
I have a question about possible electrochemical
reactions when wet etching Cr/Cu.
Copper is on top of Chrome, so I etch the copper
first, then lithography, and etch the chrome.
I tried 1020 AC and TFD from the Transene, and CR-4.
During etching, I observed that if there is a tiny bit
of copper left exposed to the chrome etchant, the
chrome etchant won't attack the chrome.
Later on I used HCl.  If I touched the chrome with my
stainless steel tweezers, HCl will etch Cr.
I think there are some electrochemical reactions going
on.
Any insights will be greatly appreciated.

Jai
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