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

Abstract

PurposeThe 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/approachBond 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.FindingsA 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 implicationsThe 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/valueThe mechanical simulation is able to replace the time‐consuming lifetime experiments.