The Influence of Stress on Aluminum Conductor Life

Stress induced failure of Al-Si metal lines has been observed in long lines less than four microns wide. The failures result from voids or cracks in metal lines and appear very similar to electromigration induced damage. However, these failures can be generated without electrical stress, and are not accelerated by high temperatures. The failures were found to be due to a combination of Coble and Nabarro-Herring creep of the aluminum, and could be prevnted by the addition of 0.5 to 2.0 % copper in the aluminum.