I'm very familiar with this problem and I have a somewhat simple
solution that's been working for me.
1. Begin with half oz copper or less
2. Caution not to overplate with copper prior to Ni Au.
3. Use a thicker dryfilm resist for the outerlayer imaging process.
This will help wherever some overplpating occurs.

The thicker the base copper is, the greater the undercut will be
making the brittle nickel more prone to breaking off.

thanks,


On 10 Oct 2002, at 16:11, Crepeau, Phil wrote:

> hi,
>
> four (maybe 3.5) decades ago nickel-gold was a common finish for pwbs.  as you might imagine, its solderability and solderable shelf life was quite good, and it fit in well with ni-au plated edge fingers.  the condition you are seeing was called gold whiskering.  it was a major pain in the
rear.  careful pwb cross sectioning was required to assure that over etching wasn't present.  solder dip and hot air leveling took care of that problem.  now, here we are again experiencing the same problem.  amazing.
>
> phil
>
> -----Original Message-----
> From: Steve Mac Donald [mailto:[log in to unmask]]
> Sent: Thursday, October 10, 2002 1:00 PM
> To: [log in to unmask]
> Subject: [TN] Undercut peeling on all Gold Board
>
>
> Good Day to everyone,
>
> We have been experiencing an issue with deep gold plating after etch.  The
> undercut is breaking away making the traces look "hairy."  The gold either
> clings and drags away from the trace or breaks loose at LPI/Soldermask and
> floats in the ink to some other undesireable location. It is not consistent
> but it is persistant.  Has anyone had this issue before and could someone
> suggest some possible solutions? (It never happens with standard copper
> plating--just deep gold.)
>
> Thanks,
>
> Steve MacDonald
> Mass Design
>
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