Yeah, unless the spacings are very tight and background Ni plating on the dielectric results in shorts (e.g. resulting from electroless plating to residual catalyst on dielectric -- sometimes caught up in roughness left where copper foil dendrites were etched away -- or incomplete etch/copper dendrite residues down in the dielectric)

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Yuan-chia Joyce Koo
Sent: Thursday, June 28, 2018 3:36 AM
To: [log in to unmask]
Subject: Re: [TN] Rough Gold causing plating shorts

immersion gold is ion exchange process (correct me if I am wrong).   
only very thin layer can be formed on the surface.  the roughness must be underlying layer or substrate plating issue... IMHO.  Not sure what actually the supplier of his was saying (it might be lost in communication).
The electroless Nickel, unless it is porous (with bubbles or P or additive clusters), it usually not rough either...Let me know if you guys observe something else in the past...
jk
On Jun 28, 2018, at 3:39 AM, FTL Quality wrote:

> Do you have some pictures to illustrate the issue?
>
> Thanks
>
> -----Original Message----- From: Wayne Showers
> Sent: Wednesday, June 27, 2018 7:57 PM
> To: [log in to unmask]
> Subject: [TN] Rough Gold causing plating shorts
>
> I need a favor in regard to rough gold (ENIG) causing plating shorts.  
> I need a brief synopsis of which process or processes typically go out 
> of balance to cause this issue.
> Basis: My supplier is indicating electrical shorts attributable to 
> rough gold being the reason for their low lot yields on a rigid flex. 
> Unfortunately, I know enough to be dangerous but not necessarily 
> effective in this realm.