Hi,

Can anyone help me?  I own all of the final finish processes at JMSPI.  I have been battling galvanic etching on final boards that have both gold and copper surfaces.  The problem seems at this point to be limited to copper features that are directly connected (usually via a trace) to a gold feature.  The means of the connection is typically covered by mask.  I have seen occurrences when we are running an etch of about 60 microinches total and have completely etched off 1200 microinch pads selectively.  Currently I am attempting to ground the bath with a true zero ground, and I have tested peroxide vs. persulfate etches.  I do not know yet what the effect of the ground will be, but the etch chemistry did little for me.  I do know that running a conveyorized horizontal spray etch seems to provide enough of a break in the solution bridge to avoid this effect.

Replies would be greatly appreciated.

Joe Aronson 
Wet Process Engineer
JMSPI

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