Hi Jim-

If you already have a Pb-free process, then using BGA's should go pretty
smoothly because many observed problems are due to trying to reflow a
Pb-free BGA with SnPb paste.  This can be done very reliably, but takes some
tweaking and experience.

Since you can't directly see the joints, Xray is one option to do some kind
of quality control kind of similar to normal microscope based inspection.
But it is not nearly as good since Xrays can't see cracks.  Yeah, they can
see voids, but most voids look worse than any reliability degradation they
cause.

Inspect the heck out of the perimeter joints.  Usually the interior ones
look the same.  Sometimes a tiny front-silvered mirror is needed to see
underneath the parts.

If you go down to smaller geometries (BGA pitch 0.7 or less), you will see
lots more problems, just like going from 0603 to 0402 to 0201.....

Wayne Thayer

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Jim West
Sent: Monday, May 05, 2014 10:26 AM
To: [log in to unmask]
Subject: [TN] Production with BGA's

Hi everyone,

A happy Monday to you all!

How many of you have experience with BGA's?  We are looking at possibly
having new designs that require BGA's.  I have never ran, nor has my
currently company, ran a process with BGA's and I'm trying to get my hands
around everything needed to be successful.  I believe my biggest concern
will be the soldering process (material and process) and inspection
afterwards.  I feel pretty confident my paste printer, pick and place and
reflow process will be capable of handling the BGA process based on feedback
from the equipment manufacturers for those machines.  I know this is a very
broad question, but what do you guys think my focus should be on based on
your experience?  I have some time to prepare, so any feedback will be
greatly appreciated.   One specific question I do have is, will I need 100%
X-Ray inspection?

Thanks,
Jim


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