Thermo-mechanical behaviour analysis of micro-solder joints by finite element modelling

Modern trends in design of electrical products require miniaturization and multi-function. In line with these trends, dimensions of lead-free solder joints reduce from over 100μm to 10μm, resulting in some new reliability issues. A high fraction of intermetallic compounds (IMC) with various shapes is a key feature in micro-solder joints. So far, few investigations focused on the influence of high fraction of IMCs on thermal fatigue, which is of great importance for reliability of electronic devices. In this work a parameterized finite element model is presented and analyzed to find out the change in stress and strain distributions in micro-solder joints. Different thicknesses and shapes of IMC are simulated. Results show that both thickness and shape of IMC have significant effects on thermal stress and creep strain.