Electromigration test structure designed to identify via failure modes

Abstract

A new type of electromigration test structure has been demonstrated, which allows detailed understanding of the electromigration behavior of inter-level vias. It is designed to test each via interface independently. It also allows easy failure analysis by constraining the failure location. An example of its application is provided, where a change in the via process led to improved electromigration behavior. The use of this test structure allowed the identification of physical mechanisms for the improved electromigration behavior.