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2009
Conference Paper
Titel
Determination of copper/EMC interface fracture toughness during manufacturing, moisture preconditioning and solder reflow process of semiconductor packages
Abstract
Interfacial adhesion is of important concern for multilayered structures such as microelectronic packages. Environmental effects, i.e., high temperatures and moisture diffusion, change the mechanical properties of polymeric materials and, more importantly, degrade the adhesion between the polymeric adhesives and substrates. Delamination between the Epoxy Molding Compound (EMC) and the copper-based leadframe during the solder reflow process is a common failure mechanism in plastic encapsulated IC devices. This work shows the influence of aging in dry and humid conditions on the adhesion between EMC and copper. Bi-layer Copper / EMC beams were exposed to moist environments to reach the saturation condition. Standard fracture tests were performed for the determination of the critical force at the moment of crack onset. The effects of thermal residual stresses, hygroscopic swelling and viscoelasticity on the measured interfacial fracture toughness for a specific mode angle were investigated by Finite Element Analysis (FEA).