Effect of thermal aging on cohesive zone models to study copper leadframe/mold compound interfacial delamination

Most microelectronic packages consist of multilayered structures made of dissimilar materials. Therefore, interfacial delamination is a common failure mechanism due to the mismatch in the coefficient of thermal expansion (CTE) between dissimilar materials. Epoxy mold compound (EMC) atop a copper leadframe is commonly used in microelectronic packages. Environmental factors such as high temperature storage and/or moisture conditioning will have a significant effect on the interfacial fracture toughness in such structures. The effect of thermal aging on the interfacial adhesion of an EMC to copper leadframe is investigated in this paper. Cohesive-zone models, which incorporate thermal aging effects, have been characterized to be able to study interfacial delamination propagation.