Hello all,

We are having an ongoing problem with solder joint failures on a 144-pin PQFP processor, after short-term vibration. The board layout and mechanical mounting apparatus were designed with vibration in mind, and have passed vibration testing in the past. The same processor is used on a dozen other assemblies, none of which have this problem.

The solder joints appear to exhibit dewetting, although there is a toe and heel fillet.  The heel fillet is unusually large, and the top of the PQFP lead has a grainy appearance instead of a matte or shiny appearance.  Some leads can be pushed off the solder joint with very little pressure.  Sn62Pb36Ag2 solder is being used, and our EMS provider continues to claim that boards meet IPC-A-610 class 2 requirements.

Any ideas as to what may be causing solder joint failures?  

Also, any suggestions or recommendations (preferred) for a test house to provide x-ray, microsection and composition analysis?

TIA & Best Regards,

Roger M. Stoops, CID+
Trimble Navigation Ltd., Dayton, OH, USA
Ph: +01 937.245.5288
Fax: +01 937.233.7511

Oh, and BTW, changing EMS providers is not an option...

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