Mitch,
   I just started using a 0.010 +0/-0.006 finished hole with a 0.018 dia pad
in a 0.093 thick FR-4 board. I have had several fabricators review this and
tell me that they could build the boards. All of the lands are teardropped
coming into the vias to prevent break-out. I am only using the small via pad
under BGA, outside of the BGA the vias are 0.025 pads.
Barbara Burcham

-----Original Message-----
From: Bates Karl [mailto:[log in to unmask]]
Sent: Wednesday, June 27, 2001 2:19 PM
To: [log in to unmask]
Subject: Re: [DC] .010" FHS, pad size issues


Mitch,
Again your doing some crazy stuff, ... maybe this web link will help.
http://www.ddiglobal.com/capabilities/ddi_design_guidelines2.html
-----Original Message-----
From: Mitch Morey [mailto:[log in to unmask]]
Sent: Wednesday, June 27, 2001 12:40 PM
To: [log in to unmask]
Subject: [DC] .010" FHS, pad size issues


Hi all,

I've got an extremely dense .093" max thick board which already utilizes
.010" finished holes for the vias (~8000 vias on the board). It's
currently using .023" pads for the external/internal layers. I'd like to
decrease both pad sizes and still keep it manufacturable. Anyone have
suggestions (aside from the "recommendation" to go to uVias!, ain't
gonna happen). I'm looking to go with .020" pads external and .022 pads
internal. This is not a production board.

Anyone going smaller than .020/.022" pads?

Thanks.

Mitch
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