Hi Dale,

How long have you been building these boards (with this design and
component)?  Has anything else changed in the PCBA process?

Do you have access to CSAM?  Take a few (10) virgin parts and examine them
with CSAM, and then take them through the reflow process with the same
profile and frequency.  Re-examine the parts with CSAM, and evaluate the
increase in the amount and location of any delaminations.  If you see
excessive delam at time zero or post stress, then that is sign that there
might be an issue with the IC Assembly and test process of these ICs.

How confident are you on the signal and power integrity design?  There might
be an issue of power integrity that you "help" by heating the device and its
surrounding capacitors...?

Interesting problem.

Regards,
Oscar



On 7/24/08, Werner Engelmaier /* <[log in to unmask]> wrote:
>
> Hi Dale,
> One other possibility presents itself. While it is unlikely that QFP leads
> are made of Alloy 42, this is easily checkable with a magnet—if the leads
> attract a magnet, they are Alloy 42.
>
> Werner
> Future workshops:
> Pb-Free Soldering Processes—Survival, Quality, Reliability, August 18,
> Orlando
> Reliability Issues with Lead-Free Soldering Processes, September 22,
> Schaumburg
> Failure Mode and Root Cause Analyses Reliability (Fatigue, Brittle
> Fracture,
> ENIG), September 22, Schaumburg
> Solder Joint Reliability: Parts 1 & 4, Oct. 9, Moscow, Russia
> Solder Joint Reliability: Parts 1 & 4, Oct. 17, Timisoara, Rumania
> Solder Joint Reliability: Parts 1 & 4, Oct. 22, Tallinn, Estonia
>
>
>
> **************
> Get fantasy football with free live scoring. Sign up for
> FanHouse Fantasy Football today.
>
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>
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