We recently qualified a SMT power module which has a small QFN part on the
board bottom side （the QFN package is intersil ISL6522 5mm×5mm）. 

After the module was soldered to our board, We often found solder jointer
open in QFN terminal for remelting

We also find one doubtful point, in general, if the standoff of QFN has
obviously height and the solder jointer has beautiful fillet, 

The module will easily have the open issue after reflow. 

So we think the problem reason is caused from the incoming parts PCBA
process control and DFM design although the incoming is good, 

Also we think the standoff of QFN in module should be controlled, otherwise
the solder jointer will have open issue in our PCBA.

Who have encountered the same issue or could give me any idea? Thanks in
advance!

 

 

Min Jun

H3C process engineer

Tel:+86-010-82774234

 

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