STRESS MIGRATION RESISTANCE AND CONTACT CHARACTERIZATION OF AL-PD-SI INTERCONNECTS FOR VERY LARGE-SCALE INTEGRATIONS

Stress-induced migration resistance and contacts to silicon of Al-0.3%Pd-1%Si interconnections for submicron process integrated circuit devices have been investigated and compared to Al-0.5%Cu-1%Si. Using creep tests, Pd has been found to be an excellent additional element to A1 for reducing grain boundary diffusion. Palladium improved the stress-induced migration resistance and reduced void and hillock formation in Al-Si conductors. Aluminum palladium precipitates in Al-Pd-Si alloys were found to be formed at higher temperatures than aluminum copper compounds and may be the reason for the improvements. The contact resistance of Al-Pd-Si was found to be similar to that of Al-Cu-Si. The reliability and yield data from 1.2-mu-m ROM test devices using Al-Pd-Si conductors is better than that of Al-Cu-Si conductors.