Relevance evaluation of solder joints attributes to reduce the variance of the lifetime model

Driven by the electrification and the increasing use of security-relevant electronics thermomechanical fatigue of solder joints gains in importance. This research investigates the geometric attributes of solder joints in a high detailed way based on two-pole resistors. Using a 3D profilometer the shape of the solder meniscus, the standoff height, the offset and the tilt angle of the component are analyzed. A void calculation based on radioscopic measurements and the results of solder paste inspection supplement the comprehensive analysis of the solder joint characteristics. These studies show correlations between the initial attributes of solder joints themselves and the thermomechanical fatigue process due to temperature cycling. The initial geometric attributes of the components are also compared with the values of the same components after thermomechanical loading. The level of damage was measured by using shear tests and a failure probability according to Weibull was determined.