I understand it can also have a negative affect on BGA's if the vias
underneath them blow during assembly...

Regards,

Ian Hanna
Quality Manager
Lazer-Tech Ltd.
Voice: 416.291.7727.233
FAX:   416.291.0325
[log in to unmask]


-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Dave Gardiner
Sent: Tuesday, October 31, 2000 8:11 PM
To: [log in to unmask]
Subject: Re: [TN] Critical question via plugging- Does need to apply from
bothsides?

If you try to plug a board from both sides you will entrap air in the middle
of the
vias. After the first side is plugged you are trying to push ink into a
closed cylinder.
This will most likely cause the some plugs to blow out of the via during
thermal
shock (paste oven or wave solder) and expose bare copper around the pad.

Dave Gardiner

Ken Patel wrote:

> Fab experts,
> After getting few responses on my previous email on via plugging, I was
> surprise to find one response saying that plugging of the via is not going
> to fill the via complete but it will rather be towards the side it
applied.
>
> So, the question is that then there is a possibility of chemical
entrapment
> from the other side so do I have to tell the fab house to plug it from
both
> sides?
>
> re,
> ken patel
>
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