Deformation and fatigue behaviour of AuSn interconnects

The knowledge of deformation and fatigue behaviour is vital for understanding reliability problems and builds the basis for mechanical simulations, which quantify strains, stresses and even product life-times. The focus of this paper is the AuSn interconnect in the form of eutectic AuSn and fine pitch flip-chip interconnects consisting in this example of an Au-phase and a zetha-phase. In the fist place local elastic-plastic properties are analysed by nanoindentation giving information about the process influences on material properties. To analyse the fracture, damage and fatigue behaviour of eutectic AuSn interconnects, special set-ups have been developed. Normal lap shear samples enable the analysis under pure mechanical load and thermal lap shear specimen enable the analysis under combined thermal and mechanical load. Thus different failure modes are outlined, which can be the focus for further quantitative analysis