Electromigration Lifetime Test in Damascene Copper Interconnects using Sudden Death Test Structure and OBIRCH

Abstract

The bimodal electromigration lifetime of damascene Cu interconnects was investigated by using a new sudden death test structure. Parameter estimation by the test structure is highly superior to that of non-sudden death approach even with a small sample size. In addition, the test structure shortens the reliability test period of electromigration. The test structure was amenable to failure analysis tools such as OBIRCH. Early failure was due to the void growth in the bottom of Via. Intrinsic failure was due to the void growth under Via.