IR-drop based electromigration assessment: parametric failure chip-scale analysis

Abstract

This paper presents a novel approach and techniques for electromigration (EM) assessment in power delivery networks. An increase in the voltage drop above the threshold level, caused by EM-induced increase in resistances of the individual interconnect segments, is considered as a failure criterion. This criterion replaces a currently employed conservative weakest segment criterion, which does not account an essential redundancy for current propagation existing in the power-ground (p/g) networks. EM-induced increase in the resistance of the individual grid segments is described in the approximation of the physics-based formalism for void nucleation and growth. A developed technique for calculating the hydrostatic stress distribution inside a multi branch interconnect tree allows to avoid over optimistic prediction of the time to failure made with the Blech-Black analysis of individual branches of interconnect segment. Experimental results obtained on the IBM benchmark circuit validate the proposed methods.