I've been afronted with the latest BGA schemes dreamed up by someone not looking at, or willing to
follow relatively simple design rules. That's my story.

I remember LPI could hold fairly tight registration dimensions and tolerances across a panel. I just
don't remember all I forgot concerning how tight these parameters might be.

The best way to describe this dilemma is to say someone designed a 432 ball permiter BGA with some
outer layer traces within 5 mils of the inside balls when 50 mils was available. With all things
considered, without redesigning, there often are traces open to the aforementioned pads. Wonder why?

The real question is what currently is reality without special "tweaking"? I mean, what are the
practical process capability limitations concerning how tight will LPI S/M cover the distance
without shorting - routinely - over say an 18 by 24 panel?

Earl Moon

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