4 ms·
I know those chips are all ball grid array or something, but how does one (or more, I suppose) of the contacts fail this way? Seems like if the package contract
by NoMoreNicksLeft 3y ago
I know those chips are all ball grid array or something, but how does one (or more, I suppose) of the contacts fail this way? Seems like if the package contracts and lifts, that the copper pad would come with it, rather than just a break in the solder. I'm not sure what I should be visualizing for a cold solder joint on surface mount...
- HPsquared 3y agoFatigue cracking from thermal expansion, and also perhaps residual stress and creep deformation. Definitely in the "mechanical engineering" realm.
- projektfu 3y agoIt's possible that there was a flaw in the original manufacture of the board and one of the balls didn't flow properly, but it passed QC.
- NoMoreNicksLeft 3y agoWouldn't that be DOA though? This has to be some sort of flaw that creeps in slowly.
- projektfu 3y agoThe flowed contacts could be holding the ball against the pad, making an electrical connection, but then the connection gets fritzy as everything warms up. Ideally it would show itself in the first run but I could also see it getting worse with time. I assume this occurred after the manufacturer's warranty expired.