Micromechanics-Based Interfacial Stress Analysis and Fracture in Electronic Packaging Assemblies with Heterogeneous Underfill

摘要

The flip-chip assembly, which is made of three main components: chip with C4 interconnects, underfill and substrate, undergoes thermal loadings during a curing process and its operational life. This analysis is focused on the delamination of the underfill from the passivation layer of a chip due to a thermal loading by using a simple model involving a finite bi-material strip. The underfill is modeled as a composite material consisting of the polymer matrix and silica particles. The interfacial stresses are determined here for several particle arrangements, while the interfacial fracture is studied using a J-integral method. The interfacial stress analysis and the J-integral method give the same trends.