Degradation of Cu-Al wire bonded contacts under high current and high temperature conditions using in-situ resistance monitoring

To evaluate the dynamics of Cu-Al bond contact degradation, the evolution of the intermetallic electrical interface resistance was monitored in-situ in a test device exposed to high temperatures (140 to 200°C) while conducting high current densities (7.0 × 10³ to 4.5 × 10⁴ A/cm²). The degradation is quite different from what is known for Au-Al contacts. The influence of different stimuli like current direction, current density, temperature, and temperature gradients is studied and discussed. On top of that the dynamics in relation to material properties is assessed in detail from which the concept of an incubation time until IMC degradation starts is proposed.