Dear Peter,
Forgive me if this has been suggested to you in earlier communications but I
have only seen your latest message. If you plan to inspect the quality of
the BGAs/process using x-ray inspection, then you might want to consider
using reflow indicators with the BGAs, as part of the design. Reflow
indicators, if you are not aware, are caused by deliberately opening up the
mask on some (or all) collapsible BGA balls which, after reflow, causes the
solder to partially flow back down the track to give a characteristic 'dog
bone' or 'key-hole' that can be clearly seen under x-ray examination
compared to 'normal' reflowed balls. Studies have shown that this does not
affect joint quality and it makes a very quick and easy check to give a high
confidence of the BGA reflow (usually more for your customers, as you know
you have a good process!). My observation is that using reflow indicators is
not taken up widely as the designers and the production people are too often
separated in the product design regime and often the production people have
little, or no, say in how design can help manufacture.
Of course, our company has a wonderful x-ray system to look at such things,
as well as all other joints and my North American colleagues, or I, would be
happy to tell you why! But whatever you decide I hope the above suggestion
is of interest.
Best regards,
David Bernard
Dr. David Bernard
Product Manager X-ray Systems
Dage Precision Industries
Rabans Lane
Aylesbury
Buckinghamshire
HP19 8RG
United Kingdom
Tel: +44 (0) 1296 317800
Fax: +44 (0) 1296 435408
E-mail: [log in to unmask]
www.dage-group.com
> -----Original Message-----
> From: Crain, Peter (GE Energy) [SMTP:[log in to unmask]]
> Sent: Wednesday, September 22, 2004 5:06 PM
> Subject: More simple BGA questions
>
> First: Thanks to everyone who gave feedback on my oven question......very
> helpful!!
>
> More BGA questions: Do BGAs require any special treatment when designing
> PCBs? Can there be top layer traces, vias, and components near the BGA? Is
> there a good general spacing around them to allow for inspection / repair?
> Can BGAs be mixed with through-hole and sustain the Wave Solder process
> (top-side of course) without the use of solder pallets?
>
> Thanks again in advance,
>
> Peter Crain, C.E.T
> Manufacturing Engineering
>
> > Network Reliability Services
> > General Electric Canada Inc.
> > 2728 Hopewell Place N.E., Calgary, Alberta T1Y 7J7 CANADA
> > Tel: 403.214.4560, Dialcomm: 8.498.4560 Fax: 403.214.4776
> > Email: [log in to unmask]
> > Website: www.gepower.com/substationautomation
> >
> > NOTICE: The information contained in this e-mail is privileged,
> > confidential and intended solely for the use of the addressee named
> above.
> > If the reader of this e-mail is not the intended recipient, you are
> hereby
> > notified that any dissemination, distribution or copying of this e-mail
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> >
> >
> >
> >
>
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