Fracture probability of MLCC in dependence of solder fillet height

This paper presents results of flex cracking experiments on Multilayer Ceramic Capacitors (MLCCs). The influence of solder fillet height, solder type and MLCC dimensions on the crack susceptibility of the component has been investigated. Subsequent statistical and metallographic analyses were carried out for more understanding of the failure mechanism. The statistical results show that the solder fillet height and solder type have a major influence on capacitors resistivity to cracks during bending. Components mounted with lead free solders have shown a higher resistivity to flex cracking. In some specimens delamination cracks on ceramic/termination interface were detected during microscopy analysis. Thermal shock cracks during cool down phase after soldering were also detected especially for capacitors with higher solder fillet.