Method for Measuring the Initial State of a Solder Joint Delamination in a 3D PCB Integration Assembly of SiC

Abstract:
This article presents a method for evaluating the initiation of delamination at a corner of a solder joint in a 3D power electronics assembly of SiC MOSFETs on a PCB (printed circuit board) substrate. This development is part of an effort to assess the robustness of technological choices for a new model of wide bandgap component assembly. These assemblies consist of a PCB substrate (layers of copper, epoxy, and glass fibers) and a soldered copper block corresponding to the heat-sink base-plate. However, conventional methods do not effectively meet the need for detecting the initiation of solder delamination for the assembly design. The method relies on potential measurements that exhibit greater sensitivity to detect the onset of solder delamination than conventional method. Finite element simulations are carried out to evaluate of the method’s sensitivity and discriminating factors such as geometry and materials involved. Based on the numerical results, dedicated prototypes of the assembly are manufactured with control of delamination initiated at a corner of the solder joint. Confrontation of experimental results and numerical studies offers good perspective as a complementary method to detect the delamination initiation propagation of joining technologies.