The product was subjected to 40 deg.C hot air blowing on the BGA area and it works pretty well. The product then failed when the temperature became 36 deg. C as the hot air blower is withdrawn.
If it is due to ESD then it should be a total failure I supposed.
We check the component storage until its use in the line but we couldn't find any MSD handling issue. The reflow profile for this BGA is within the specs. and X-Ray analysis reveals no unusual shape of the balls.
We suspect that there is a contact problem either on the ball-substrate or ball-solder pad. It may be also that something is wrong with the die/chip inside though we could not confirm it.
Has anybody had experience this kind of problem in their facility?
I need help understanding your problem. * What�s the difference between �e-test failure� and �total failure�? * Why do you think that an ESD induced failure would only be a �total failure�? * What if this is caused by a cracked solder connection? You would see that with your xray thingamajig, would you?
If I hear [read] you correctly, the board tests: * Fine with the hair dryer going. * Poorly with the hair dryer turned off.
If so, can you make contact by pressing on the BGA and pass the test with the hair dryer off?