Hi George,
Would you mind elaborating on  "mechanical overstress" - I have not heard that term or description before. Thanks. Steve Kelly

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Wenger, George M. [Contractor]
Sent: August-06-14 3:02 PM
To: [log in to unmask]
Subject: Re: [TN] SJ fracture signature

Hi Chris,

I don't think that EDS maps will tell you anything more than you can obtain from the optical photomicrographs of the cross section.  Looks like a typical solder joint mechanical overstress.  It certainly isn't a brittle fracture at a solder/IMC interface that one might expect after a sudden impact or drop test.

Regards,
George
George M. Wenger
Failure Signature & Characterization Lab LLC
609 Cokesbury Road, High Bridge, NJ 08829
(908) 638-8771 Home  (732) 309-8964 Mobile E-mail [log in to unmask] [log in to unmask]

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Chris Mahanna
Sent: Wednesday, August 06, 2014 2:49 PM
To: [log in to unmask]
Subject: [TN] SJ fracture signature

We see hundreds of cracked solder joints every year, but I can't say that I've ever seen one quite like this.  I have some suspicions, but I'll keep them to myself, as to not prejudice the crowd.
EDS maps are forthcoming.

This is a caught in-the-wild field failure of a 48-pin BGA Reballed to SnPb ENIG on board side Ni barrier on component side

http://stevezeva.homestead.com/45268-1.JPG

http://stevezeva.homestead.com/45268-2.JPG

http://stevezeva.homestead.com/45268-8.JPG

Thoughts?  And Thanks to Steve!


Chris Mahanna
President, Technical Manager
Robisan Laboratory Inc.


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