All,

The holes are anywhere from 1 to 5 microns in size that I am unable to
etch through.  I have tried sodium lauryl sulfate as a surfactant in the
Iodine etching solution with no success (even when using ultrasonic
agitation).

What I need (in my opinion) is a chemical etchant that's smaller than
iodine & less toxic than cyanide.  I need to be able to get a gold
etchant through copper micro-holes (about 2 microns in size).

Thanks for all your efforts,

Dave Lewis
Lake Shore Cryotronics
Ohio
Dave.Lewis@Lakeshore.com