My two cents:

Typically, you will use epoxy to plug the via. I am not sure what you meant
by solder plugging. As for the fab drawing, you can put a statement like
this

THE VIA HOLES BENEATH THE BGA AREAS MUST BE PLUGGED SUCH THAT IT WILL NOT
CAUSE SOLDER DRAIN DURING SOLDERING (REFLOW OR WAVE). THE MAXIMUM SOLDERMASK
AND VIA PLUG THICKNESS OVER THE ANNULAR RING SHALL NOT EXCEED 2 MIL (TO
AVOID EXCESSIVE GAP DURING PRINTING).

Ideally, you should create a separate layer in your Gerber files to indicate
the exact plug locations to avoid confusion. Also, if you are using HASL. Do
you want to plug the via before or after HASL? Some board houses will have
difficulties if you want to plug after HASL. Besides, if you have a choice
to plug from either top or bottom, I personally prefer top side.

Hope that helps,
M. Yuen

-----Original Message-----
From: Lam, Patrick [mailto:[log in to unmask]]
Sent: Thursday, July 05, 2001 11:41 AM
To: [log in to unmask]
Subject: [TN] Plugging vias on BGA pads


Hi TechNet's,

Would some of you tell me the proper way to handle this:

I have 10 mil through hole vias on BGA pads. Is solder plugging these vias
on the BGA side the proper way? What is the proper way to document this on
the Fab. drawing?

Thanks,

Patrick Lam
Phone:(604)293.4392

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