Hello Folks,

Could anyone please advise on what realistic long term storage (many years) can
be achieved, and how to achieve it, for components such as integrate circuits?
Any articles or guidelines would be helpful.

We are facing some obsolete component issues and do not have resources to
redesign many boards for incompatible replacements or new devices.

After searching the archives I have ascertained that it seems the hygroscopic
nature of the packages is not a great problem. J-STD-033 should help with
determining storage requirements for this issue. Would it be true to say baking
the components can eliminate any absorbed moisture, even after many years of
long term storage?

A bigger problem appears to be intermetallic growth on the legs, between the
coating (tinning) and the actual leg material.  The intermetallic can grow over
time, eventually causing the legs to lose solderability.  I suspect the growth
rate is temperature dependent and could be slowed by cooling.



Regards,

Colin Weber

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