SWEAT structure design and test procedure criteria based upon TEARS characterization and spatial distribution of failures in iterated structures

The authors consider the prime issues that should be raised when one considers the design of a test system and the procedure to be involved in the test. An extended TEARS (Thermal Energy Accounts for the Resistance of the System) analysis yields end-to-end temperature profiles of an N-fold iterated SWEAT (Standard Wafer-level Electromigration Acceleration Test) structure. The results give guidelines for the choice of voltage probe locations and current injection line lengths and also permit relating measurements on SWEAT structures with different numbers of elemental units and different geometry. Asymmetries in the first and last units correlate with the observed spatial distribution of failures. Criteria for much more rapid convergence and more accurate control of sample stress are presented.<>