New technique and analysis of accelerated electromigration life testing in multilevel metallizations

Abstract

Electromigration failure of a series-parallel configuration of aluminum interconnects overlayed on tungsten contacts was measured using a novel multiple lognormal analysis. The analysis examined early failure mechanisms and allowed rapid determination of electromigration parameters on a statistically large number of junctions. The primary failure mode of these stuctures was complete migration of Al off of the W pads. This work suggested that Al/W metallizations, with a large number of series contacts, are prone to short mean time to failures.