Hi Bev,
Your question about whether ultrasonic methods for delamination detection in
components are powerful/sensitive enough to find either gross opens and/or
hairline cracks in the BGA solder joints is a good one, and I do not have an
answer. However, the effectiveness of this technique will clearly depend on
the rigidity of both the BGA and the MLB—the more rigid, the less effective.
The reason for this is that the electrical failure detection will depend on a
very short-term separation of the fracture surfaces, which will be easier to
accomplish if the BGA/MLB are more flexible.

Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL  32174  USA
Phone: 904-437-8747, Fax: 904-437-8737
E-mail: [log in to unmask]


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