It has recently, and disruptively, been brought to my past ignorant
attention the problem associated with electroless nickel deposition
under electroless gold deposited SMT solder termination areas. I have
been informed, by a major BGA supplier, the deposition process relies on
phosphorous as a component in the plating solution. Further, I have been
told this is detrimental to solder joint formation.

It is said, and has been proven by the BGA supplier, that phosphorous
causes solder joint problems by forming an internetallic that, over
time, causes embrittlement. Therefore, solder joints fail.

Has anyone in industry addressed this issue from a PCB fabrication
standpoint? If so - how, and what is being done? Can we specify
electroplated nickel in approximately 100 millionths thickness as for
electroless types? If so, will this overcome the intermetallic,
embrittlement, and solder joint problem?

Thanks, Earl Moon

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