Hi,

 I am very interested in how this turns out.

 Here we have a known problem at a known location and neither 2D or 3D X-Ray
show the error. Did I get that right?

 This makes me question X-Ray inspection as a general inspection method. If
you have a blob of solder under a part sure. But opens seem to be an issue?

 Am I overly critical of X- Ray here?

Thanks,
Bob K.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Leland Woodall
Sent: Thursday, December 02, 2010 10:36 AM
To: [log in to unmask]
Subject: [TN] BGA Failure Analysis Recommendations

Good morning, everyone!

I'm looking for some advice on how to best analyze a BGA problem.  We had an
assembly to fail in a reliability test, and have isolated the problem to an
intermittent contact on the BGA device.  When downward pressure is applied
to the component it will pass.  Without the pressure, it won't.

That tells me we have either fractured a joint, had a ball to separate from
the package, or had a head in pillow (or non-wet) condition.

We don't have a BGA inspection scope in house, and I can only see two of the
four outside edges with the equipment I have.  Of course, nothing is wrong
with those.

We have both 2 and 3D xray machines, but neither detect a flawed condition.

At this point, do I go with dye and pry, or conduct a series of cross
sections?

What's the recommendations of the pros out there that have dealt with this?
Your suggestions are sincerely appreciated!

Leland Woodall

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