Hi Leland,

A good quality X-ray is a must thing to do first. Depending on the results, sectionning or Dye&pry should follow. 

We do that kind of failure analysis for our customers, so you may want to consider sending us the assembly for analysis. 
Vladimir

SENTEC Testing Laboratory Inc.
11 Canadian Road, Unit 7.
Scarborough, ON M1R 5G1
Tel: (416) 899-1882
Fax: (905) 882-8812
www.sentec.ca

-----Original Message-----
From: Leland Woodall <[log in to unmask]>
Sender: TechNet <[log in to unmask]>
Date:         Thu, 2 Dec 2010 10:35:46 
To: <[log in to unmask]>
Reply-To: TechNet E-Mail Forum <[log in to unmask]>,
        Leland Woodall <[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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