Here is my issue.

 

We have a CM that x-rays 100% of the BGAs on our product and notes no abnormalities. We might have some micro cracking at the ball joints.  (This was discovered because the product electrical properties are intermittent when we press the BGA down.).  In addition to having our CM x-ray the board we had an outside company perform this inspection with the same results.  If it is not micro cracking we are un-clear what else can be causing this abnormality.

 

Any suggestions on how and what we can do to capture this abnormality in production?

What type of screening can be done after production? (We have performed a static thermal testing (-0 to 125 degrees) with no failures after testing.

What other type of testing or inspection can be performed to evaluate ball joints on BGAs?

 

Thanks David.