Design of a test structure to evaluate electro-thermomigration in power ICs

The design of a novel test structure to study the influence of electromigration and thermoinigration in the large dimension metal lines used in power integrated circuits is reported. Incorporated into the test structure are a heating element and a number of temperature monitors, to enhance the thermal gradient and to measure it, respectively. Therinal simulations have been performed and compared with the electrical characterization carried out on a set of test structures. The agreement between simulation end electrical measurements has been proved confinning the validity of the test structure as a vehicle for a deeper understanding of the reliability of the line under the influence of thermal gradients.