Study of the Effect of Solder-Joint Voiding using X-ray MicroCT Data-based FE Models with Experimental Validation

摘要

Assessment of thermal cycling fatigue reliability requires methods to accurately model variance in the part and interconnect geometry including the presence of solder-voids and joint imperfections. Solder interconnects of the same package assembly may not be identical, often exhibiting variation in the assembled height, and presence of voids stemming from manufacturing process and material variances. Common FE modeling approach for life prediction involves the assumption of nominal geometry and dimensions of the part and solder interconnect but do not take into consideration the part-to-part geometric variability. In this paper, a new method to create finite-element models using x-ray micro-computed tomography data of the actual part assembly has been presented. The method has been applied to an assembled QFN part. Thermos-mechanical reliability of the part assembly has been simulated. Life prediction has been pursued using the inelastic strain energy density based damage relationship. The model has been validated with experimental data.