Hi TechNet - Bev's comments are correct -  the IPC JSTD 001 subtask group
under the direction of Les Hymes did meet at the IPC Expo Conference in
April. I don't have my notes on which void %  values were selected but when
Jack Crawford gets back from vacation (he's out this week) he will be able
to pull up that data and  post it on TechNet. There was quite a bit of
debate on the allowable void subject and there has been test data submitted
to the subtask group. The subtask group's recommendations will show up in
the next revision activity on JSTD-001 as a proposal in section 9.

Dave Hillman
Rockwell Collins
[log in to unmask]





Bev Christian <[log in to unmask]> on 06/24/98 02:18:50 PM

Please respond to "TechNet E-Mail Forum." <[log in to unmask]>; Please respond
      to Bev Christian <[log in to unmask]>

To:   [log in to unmask]
cc:    (bcc: David D Hillman/CedarRapids/Collins/Rockwell)
Subject:  Re: [TN] void size specification for BGA's




Friends,
We had a good discussion on this at the IPC meeting in Washington in a
session committee chaired by Les Hymes.  There is no standard (yet), but it
looked like Celestica, Motorola and Honeywell may have the most info on
this.  Motorola data suggests that voiding (within limits) is a good thing
in that the voids are crack arrestors.  I did not make the equivalent
committee meeting in Long Beach, so I do not know where it went after that.
Jack?  Anybody?

My guess is that we will end up with a standard allowing somewhere in the
15-25% range with a certain limitation of the size of any one void.  I
would
really like to hear what others have to say on this now.  I know this has
been discussed before, but perhaps now more people have some experience and
more reliability work has been completed.

regards,
Bev Christian
Nortel

> ----------
> From:         Gabriela Bogdan[SMTP:[log in to unmask]]
> Sent:         Wednesday, June 24, 1998 2:32 PM
> To:   [log in to unmask]
> Subject:      Re: [TN] void size specification for BGA's
>
> Ken Patel wrote:
>
> > Is there an IPC void size specification for BGA's detected by
> > transmission
> > X-ray or industry defecto standard?
> >
> > re,
> > ken patel
> > ______________________________________________________
> > Ken Patel                       Phone:  (408) 490-6804
> > 1708 McCarthy Blvd.             Fax:    (408) 490-6859
> > Milpitas, CA 95035              Beeper: (888) 769-1808
> >
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>    Ken,
> The only reference I know is on Bob Willis's site and in the last
> Bellcore 78 spec which states
> a ridiculous 1%.
> I am dying to find out other reasonable requirements too.
> Please include me in your mail.
> Gaby
>
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