Thanks Russ!
Gaby
----- Original Message -----
From: "Russell Burdick" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Saturday, July 05, 2003 3:30 AM
Subject: Re: [TN] Nickel separation


> I'm not sure this applies...I have seen first hand another failure of EN
> separating from copper, although prior to assembly. An operator
> mis-calculated the copper microetch rate leading to insufficient copper
> roughening. The problem was caught when inspection tape tested the ENIG
and
> pulled up nickel from the copper surface. Operator logsheets contained the
> raw data for the etchrate calculation so a swift root cause was mercifully
> easy. Process wise we dumped and remade the acid pre-dip each day as Rudy
> mentioned.
>
> I hope this helps in some way.
>
> Russ
>
>
> >From: Gaby <[log in to unmask]>
> >Reply-To: "TechNet E-Mail Forum." <[log in to unmask]>,
> >Gaby <[log in to unmask]>
> >To: [log in to unmask]
> >Subject: [TN] Nickel separation
> >Date: Sat, 5 Jul 2003 01:18:26 +0200
> >
> >Dear TechNetters,
> >We encountered an unusual failure .
> >After mounting and reflowing BGA's on a ENIG plated board, they failed
the
> >electrical test showing opens and intermittent contact.
> >We tried to repair the failure by reflowing them again with our SRT,
after
> >developing a good profile. The result was that some of the opens
> >dissappeared, but new ones appeared.
> >We decided to remove the failed BGA and replace it with a new one. After
> >removal of the old component , we tried to prepare the circuit pads for
> >replacement. During this operation we observed that the nickel plating
> >separated from the copper on many pads and after performing a cross
section
> >of the area. we saw that other pads had nickel separation and solder
under
> >the nickel (which creeped there during pad preparation).
> >It is the first time that I saw this failure.
> >Any comments?
> >Gaby
> >
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