Hi

There are two technical papers concidering this problem:
A Root cause failure mechanism for solder joint integrity of electroless
nickel/immersion gold surface finishes;Nicholas Biunno, Hadco; Presented at
IPC Printed Circuits Expo 1999 and
ITRI Project on electroless nickel/immersion gold joint cracking; Bruce
Houghton, Celestica; Presented at IPC Printed Circuits Expo 1999.

As far as I know, there is no fix.

B.R.
Jarmo Kiiski

> -----Original Message-----
> From: Michael Forrester [SMTP:[log in to unmask]]
> Sent: 30. toukokuuta 2000 19:43
> To:   [log in to unmask]
> Subject:      [TN] Black nickel barrier problem w/immersion Ni/Ag
>
> On a recent run of Ni/Ag boards (SM & PTH) we had solderability problems,
> especially on the thru-hole components.  Upon investigation by the board
> manufacturer,
> it was reported as a black nickel barrier problem.  Apparently this is a
> by-product of the immersion gold plating process.  What exactly is it,
> what
> causes it, and is there a way
> to prevent it?  Is there a way to "fix" a batch of boards with this
> problem?
> Thank you.
>
> Best Regards,
>
> Mike Forrester
> LeCroy Corp.
>
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