Fortunately, I haven't had to do that yet....

The only way I have heard to do it is to us a .1mm grid and use .1mm spaces
and traces.
With a .5mm via pad (almost 20mils) you can still drill a decent hole, even
though that
is stretching your 7:1 requirement,
and .1mm spaces and traces (3.937mil) is only robbing the board house a
little bit, right?
<grin>
Your board house will moan and groan but say it is do-able
but if you can't get away with that, you will have a difficult time of
it...!

Good luck,
Jack


 -----Original Message-----
From:   Mitch Morey [mailto:[log in to unmask]]
Sent:   Monday, September 18, 2000 12:17 PM
To:     [log in to unmask]
Subject:        [DC] Recommendations? 1mm BGA vias,2 between traces

Hi all,

I'm looking for some help. I've got some 1mm BGAs on my board, and I
need to get two between routing on the inner layers without going to
uVias. I'm currently trying with .012" FHS vias, but they don't do two
between. The board is .070" thick and I can go to an 8/1 aspect ratio.
Give me your best shots...

TIA.

Mitch
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