Tombstoning is a well known issue for SMT soldering and is usually caught at post solder visual inspection. However, at times the effect is a subtle lifting at one end of the component as was the case in this example of an SMD inductor. The failure was a high resistance in the associated signal net that wasn’t detected until final assembly and testing of the product.
This is a BSE SEM image of a microsection of the device as soldered on the PCBA.
The high resistance was caused by a failure of the original solder reflow process to wet the termination, which caused “tomb stoning” of the inductor.
Check out SEM Lab, Inc. to learn more.
John says:
I have been doing soldering for many years and know tombstoning effect. But, I never saw the cross section of the solder with the effect at this detailed level before. It looks amazing.
riemerzajicek says:
Thanks John!
Cuong says:
hi john !! nice to meet u