Effect of Joule Heating on electromigration in dual-damascene copper low-k interconnects

The effect of Joule heating (JH) on electromigration (EM) was investigated using copper low-k interconnects. We found Black's empirical EM model works at a very wide stress conditions (I = 0.03 mA ∼ 3.5mA), where the temperature rise by JH ranges from 0°C to 240°C. EM modeling parameters were found to be 1.05eV and 1.4 for EM Ea and n, respectively. Extensive failure analysis and FEM simulations were carried out to understand the EM failure mode at various JH conditions and provide guidelines for the usage of JH-assisted EM test method and design-reliability rules.