Hi gang! I have been looking for some data and am not having any great 
success so I thought I would ask TechNet! I am looking for solder joint 
integrity data for BGAs and CSPs where you have a two sided board and the 
BGAs or CSPs are "mirrored" (aka side one has a BGA exactly opposite of a 
BGA on side 2).  I have found publications discussing the impact of 
mirrored BGAs due to rework but I am looking more specifically for the 
influence of having a mirrored configuration  (or even a partially 
mirrored configuration) on the solder joint integrity in thermal cycle 
conditions. There seems to be some industry tribal knowledge that having a 
mirrored BGA/CSP configuration causes a degradation in solder joint 
integrity but I am not finding supporting data in the industry literature. 
If you know of any published papers/reports, please send me the citation 
and I can run down the papers. 

TIA

Dave Hillman
Rockwell Collins
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