Developing a model for the bond heel lifetime prediction of thick aluminium wire bonds

Purpose - The purpose of this paper is to establish a law on the durability of thick aluminium wire bonds in low cycle fatigue for different geometries and wire diameters under a purely mechanical load.Design methodology approach - Bond wires with different geometries were tested with various loads and a mechanical test bench, and their endurance was determined. The same load situation was modelled with finite element analysis and then compared against the experimental results.Findings - A correlation was found between the plastic strain per cycle and the determined lifespan. Therefore, the lifespan can be calculated by mechanical-plastic simulation for various loop geometries and loading cases.Practical implications - The loop height strongly influences the durability of the wire bond, whereas other parameters, such as the loop angle, have a weaker influence on the bond heel lifetime.Originality value - The mechanical simulation is able to replace the time-consuming lifetime experiments.