Isothermal wafer-level electromigration test for the characterization of metal system reliability monitoring

A fast isothermal wafer-level electromigration method has been demonstrated to evaluate interconnect metal line performance. The stress current is increased quickly until the metal line temperature reached the stress target temperature. This test method offers a significant short test time and rapid feedback to bring reliability issues into the development process. Interconnect metal lines with width/thickness of 0.9 μm/4000 Å and 1.2 μm/8000 Å of this study were processed and stressed. Results show that the metal line mean-time-to-failure and resistance are affected when the dimension is lost. This isothermal electromigration test methodology is therefore shown to be a useful tool for process monitoring