This is interesting...  is anyone addressing the ENIG sometimes used on the
BGA component prior to ball attachment?

Jim Marsico
Senior Engineer
Production Engineering
EDO Electronics Systems Group
[log in to unmask] <mailto:[log in to unmask]> 
631-595-5879


        -----Original Message-----
        From:   Tegehall Per-Erik [SMTP:[log in to unmask]]
        Sent:   Tuesday, October 07, 2003 3:02 AM
        To:     [log in to unmask]
        Subject:        Re: [TN] ENIG solder joint embrittlement

        Eddie,

        As David already has pointed out, it is soldering to a nickel
surface that is the issue, the gold layer is too thin to cause gold
embrittlement. Below are two quotations from a draft of IPC-7095A, "Design
and Assembly Process Implementation for BGAs", supporting that solder joint
embrittlement is indeed an issue when ENIG is used.

        "Recent preliminary analysis indicates that the BGA brittle solder
joint fracture happens under a high level of both applied strain and strain
rate even if hyperactive corrosion (i.e. "black pad") does not take place".

        "Based on industry experience over the past several years, it
appears that BGAs and nickel surface coatings may not be an ideal
combination. If nickel surface coatings are used with BGAs it is recommended
that the BGA surface area not exceed 25 mm2."

        Per-Erik Tegehall
        IVF
        Sweden

        -----Ursprungligt meddelande-----
        Från: Eddie Rocha [mailto:[log in to unmask]]
        Skickat: den 6 oktober 2003 23:51
        Till: [log in to unmask]
        Ämne: [TN] ENIG solder joint embrittlement


        Does anybody have data or literature which shows that solder joint
        embrittlement is not an issue when ENIG is used? I have a customer
        that needs this supporting data before he can allow us to use ENIG.
Is
        this embrittlement issue related only to a certain thickness of
gold?
        I'd appreciate any feedback on this topic.
        thanks,

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