Ronan,
Work by Motorola, presented by Andrew Mawer, points in the direction of
voids not necessarily being a bad thing.  One of the committees of the
IPC is trying to formulate a spec for an upper limit on the amount of
voids.  Consensus (early days yet) seems to be centering around the 20%
range.

Bev Christian
Nortel

>----------
>From:  [log in to unmask][SMTP:[log in to unmask]]
>Sent:  Tuesday, November 11, 1997 4:56 PM
>To:    [log in to unmask]
>Subject:       [TN] Voids in Eutectic BGA joints
>
>Can anyone shed some light on the effect of voids of various diameters in
>eutectic BGA joints?  I have heard claims that they can suppress crack
>propagation in  joints under cyclic conditions.  Is this true, or are voids
>more undesirable than desirable?
>
>Any comments would be much appreciated.
>
>Ronan Kennedy
>Manufacturing Engineer
>3Com Ireland
>
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