State-of-the-art of the bond wire failure mechanism and power cycling lifetime in power electronics

The purpose of this paper is to obtain the development direction for improving the reliability of bond wires effectively in power electronics through overviewing the state-of-the-art of the bond wire. The failure mechanisms and power cycling lifetime of bond wire under different factors and the physic-of-failure (PoF) lifetime model which related to the specific failure mechanism are the main two objects. After the influence of different factors on the bond wire reliability has been analyzed, the suggestions to improving the bond wire reliability are obtained, such as optimizing the bonding parameters, replacing the aluminum wire with copper wire, adjusting the shape of the bond wire by reducing the diameter of the bond wire and increasing the aspect ratio of the bond wire loop, increasing the number of bond wires, and using the coating material with a higher Young's modulus and high Tg. For the bond wire with different failure mechanisms, the common adopted physic-of-failure lifetime models are presented and its suitable applications are analyzed. Finally, aluminum ribbon is suggested to replace aluminum wire to improve the connection reliability in power electronics considering its many advantages.