New models for interconnect failure in advanced IC technology

The two major interconnect failure modes most commonly considered in IC technology are electromigration (EM) and time dependent dielectric breakdown (TDDB) in interlevel dielectrics. In order to evaluate reliability, tests must be performed under conditions that are much more severe than those expected under normal use in order to obtain failure statistics in reasonable times. These tests only make sense if the extrapolated lifetimes and failure distributions can be extrapolated back to use conditions, so that assessments of the reliability under normal operation can be made. The simple use of the traditional Blackpsilas Law for EM and either the E or 1/E model for TDDB can be shown not to provide accurate projections of product lifetime in the light of recent knowledge of the failure mechanisms. In this paper, the most recently developed techniques for extrapolating test data to use conditions will be described with suggestions for determining operational reliability performance.