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Subject:
Re: ASSY: BGA sanity check
From:
Fulton Feng <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Wed, 1 Jul 1998 19:23:37 -0400
Content-Type:
text/plain
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text/plain (114 lines) 
FYI

> -----Original Message-----
> From: Maguire, James F [SMTP:[log in to unmask]]
> Sent: Wednesday, July 01, 1998 8:31 AM
> To:   [log in to unmask]
> Subject:      Re: [TN] ASSY: BGA sanity check
>
> Jerry,
>
> We recently did some testing of "double sided reflow" related to
> reliability. In our testing we were wondering if reflowing a 2nd time
> with the part on the "bottom" of the PWB (so gravity pulls the part away
> from the PWB surface) would impact reliability (and also, if it would
> stay in place during reflow).
>
> Our results showed a) it stayed in place and b) no impact on reliability
> (we've passed >1600 cycles -55/125C thermal shock with 30 min. dwells at
> temp per side without any electrical intermittents.
>
> Jim
> ================================================
> James F Maguire
> Associate Technical Fellow
> Boeing
>  Information, Space & Defense Systems - Phantom Works
> phone  (253)657-9063
> fax         (253)657-8903
> pager   (206)982-3737
> email     [log in to unmask]
> =================================================
>
> > ----------
> > From:         Jerry Cupples[SMTP:[log in to unmask]]
> > Reply To:     TechNet E-Mail Forum.;Jerry Cupples
> > Sent:         Tuesday, June 23, 1998 3:15 PM
> > To:   [log in to unmask]
> > Subject:      [TN] ASSY: BGA sanity check
> >
> > Hello, TechNet....
> >
> > Soldering (inline convection furnace) BGA's on both sides of a board
> > is
> > beyond my own experience, but it seems to violate a principle (at
> > least an
> > imaginary one) related to the controlled collapse, or perhaps liquids
> > under
> > tension.
> >
> > For a board design using 3 commercial BGA packages (PBGA 256, eutectic
> > balls on 1.27 mm pitch), am I obstinately blocking the path of
> > progress by
> > requesting that this package style be confined to only one surface of
> > a new
> > board design?
> >
> > If you are doing this today and it is a piece of cake, go ahead and
> > brag;
> > but I would prefer to hear that caution is well advised, i.e. tales of
> > misery, shame and corporate disaster resulting from such mistakes. ;-)
> >
> >
> > cheers,
> >
> >
> >
> >
> > Jerry Cupples
> > Interphase Corporation
> > Dallas, TX USA
> > http://www.iphase.com
> >
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