Hi Peter - Sue and Richard gave you the critical parameter  = proper
storage. The two primary processes you want to stop or significantly slow
down: the oxidation of the solderballs and the absorption of water by the
BGA laminate/molding. If you use the industry MSL bags designed to control
moisture diffusion, use desiccant, use an inert gas such as argon or
nitrogen and then store the bags in a controlled environment, you will
address both issues and should be able to get a 5 year use life. Most folks
try to cut corners/costs and do things cheaply which dooms their potential
for success.

Dave Hillman
Rockwell Collins
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On Tue, Apr 7, 2015 at 8:53 AM, Peter G. Houwen <[log in to unmask]>
wrote:

> We have an FPGA that may not be available to us soon.  One of the options
> available to us to avoid a redesign is to buy 5 years' supply of the BGA.
>
> I'm being asked to analyze the risk factors (and we need an answer today
> of course)
>
> We can easily bake parts for moisture, but what about plating degradation
> on the balls?  Any other problems I might expect?
>
> I assume that even with baking we should expect some yield reduction, but
> I can't begin to guess how much.
>
> Thanks,
>
> Pete
>


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