Not all solder radiate alfa. In the SPACE industry, we buy special approved
solder. but to a huge cost (as for everything marked SPACE). There is
further ways to avoid changes of the semi state and it's called radiation
hardened chips. Not a cheap way either. My opinion is that the residual
alpha emission is not a problem for earthling's electronics, because the
distance and material barrier is enough a protection for most packages.
Flipchips may be different. Anyway, statistics show that the status change
frequency is something like one incident per one millions gate per one
million operational hours. If anyone is interested in more precise facts, I
think it's possible to get something to read.

Inge

On 6 March 2012 17:57, harvey <[log in to unmask]> wrote:

> Could this be true only of 63-37 or would lead-free SAC alloys also be
> potentially guilty of causing soft errors?
>
>
>
> ----- Forwarded Message ----
> From: "Gandhi, Mahendra S (AS)" <[log in to unmask]>
> To: "[log in to unmask]" <[log in to unmask]>;
> "[log in to unmask]" <[log in to unmask]>;
> "[log in to unmask]" <[log in to unmask]>
> Sent: Tue, March 6, 2012 8:38:40 AM
> Subject: Help. Is this true??
>
>
> Evidently regular solder has decaying Uranium in it, or somehow generates
> alpha
> particles, which are being blamed for upsets.  Some chips are moving to a
> special “low alpha” solder internally to avoid this problem on
> bump-grid-arrays
> in  flipchip parts.
>
>  Mahendra Gandhi
> SME - PWB Technologies
> Aerospace Engineering
> One Space Park, M5/1085A
> Redondo Beach, Ca. 90278/*[log in to unmask]
> (Office: 310.813.6857 Fax: 310.812.8630
>
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