Multilink structure for fast determination of electromigration threshold product

In this paper we report on a multilink electromigration test structure in which the current density is varied for the different links. We show the time to failure can be determined for each link by analyzing the resistance vs. time characteristic of the whole chain. Distributions of the obtained times to failure are then used to compute electromigration current exponent and threshold product. Both parameters can be determined with satisfactory accuracy by performing a reduced set of experiments. This structure and method can therefore be employed to significantly reduce experimental workload and cycle time usually required for complex electromigration parameters determination, such as electromigration threshold product.