In addition to Nick Biunno's work, ITRI (Interconnection Research Institute)
is conducting a study on this very same issue. The group is in Phase II of
the testing. They have concluded (based on Phase 1) that the thickness of
the nickel (as long as it is > 100 microinches) the high phos content is not
an issue. Low phos can be a problem as it will affect solderability. ITRI
has corroborated other studies (Biunno) that the rot cause is hypercorrosion
of the nickel by the immersion gold solution. It has been suggested that
board design may be a factor in this problem. (See "Proceedings of the IPC
Third Annual Summit on Surface Finishes and Solderability" and read the
paper by Bruce Houghton of Celestica.

Thanks,

Mike

        -----Original Message-----
        From:   Paul Klasek [SMTP:[log in to unmask]]
        Sent:   Tuesday, October 12, 1999 6:37 PM
        To:     [log in to unmask]
        Subject:        Re: [TN] Black Plague

        Have little to add to Robert's , as Earl said .
        That is what i meant saying the Ni is gone .
        To Paul's : heard the phosphorus limit in bath should be kept below
5% ?
        Is that realistic ?

        Paul Klasek
        ResMed

        -----Original Message-----
        From: Hollandsworth, Ron [mailto:[log in to unmask]]
        Sent: Tuesday, 12 October 1999 22:53
        To: [log in to unmask]
        Subject: Re: [TN] Black Plague
        Importance: Low


        Franklin, POD, & Paul
        You say there are ways to get around the Black Plague.  Would you
elaborate
        please.  Once again I see messages where others are experiencing
this
        problem but no absolute solutions.  I have read the articles, tried
the
        erasers, stronger fluxes, and pad scraping.  No relief.  I have
learned to
        dislike Electroless Ni/ Immersion Au boards.  I am thinking that
HASL or
        precision pad technologies are much better.  At least you can
perform your
        soldering operation.  A Circuit Card Assembly (CCA) with the Black
Plague
        can run up scrap costs real fast.  Not to mention the possibility of
late
        shipment to the customer because of inability to solder. This is a
real
        problem if you are using Ni/Au boards.  So far there are few
comments and
        the issue simply drops out of sight.  Are platers/fabricators not
        controlling their processes or is this a inhouse process issue.  We
have
        checked our processes and find no change.

        Ron Hollandsworth

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