Hello,


I am investigating failures occurring on plastic encapsulated thick film
substrates. The failures are pin-pin shorts due to Pb migration from high
Pb solder attaching the I/O pins to the alumina. The migration happens
after an unbiased autoclave test where the components have first been
solder dipped. The migration appears as random deposits of Pb between the
leads and usually follows the edge line of the overglaze.

My question is: Is it possible to get electromigration in an unbiased
autoclave or is this more likely to be dissolution of the Pb due to
residual contaminants?

Any help on this one would be greatly appreciated.

Rory Doyle



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            Rory Doyle            [log in to unmask]

      National Microelectronics Research Centre,
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