Analysis of Thermally-Induced Stress in Bonding Wire

In today’s advanced electrical technology, it has become a necessity to use compact semiconductor chips in a variety of applications including computers, electrical appliances, and automobiles. This creates a need for more sophisticated electrical packages. Wire bonding is used to make interconnections between integrated circuits (IC), other semiconductor devices, and their packages. Because of its wide applicability, reliability of wire bonding in power electronics is a subject of critical interest for many companies and laboratories. In the last decade, reliability problems of thick bonding wires have been studied and are considered critical for power modules. The current flow through the bonding wire induces Joule heating which results in thermomechanical stress. Research groups at the University of Waterloo, including the Centre for Advanced Materials Joining (CAMJ) and the Nano and Micro Systems Laboratory (NMSL), are currently studying failure mechanisms of bonding wire.

Turker Dagdelen, a graduate student at the University of Waterloo, modelled the electro-thermal stress of a curved bonding
wire, Figure 1, as part of his Master’s Thesis.

Figure 1: Wire bonding schematic diagram