Tech Netters

I have a question for you on micro BGA's and I don't want this to be
confused with the recent discussion on via-in-pad which may still be in
process.

The working draft copy I have of "Design and Assembly Process Implementation
for BGAs" states on page 63 that a 0.1 mm micro via may be placed in the BGA
solder land to allow more space for routing of traces.  They say the only
noticeable affect is a small dimple.  I seem to remember articles in
literature about outgassing and large voids in the BGA solder ball centered
over the embedded via.   Could anyone comment on their experience placing
microvias in BGA solder lands and if they agree with this comment in the
design guide?

                Jim Kittel

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