An in-process monitoring method for electromigration resistance of multilayered metal interconnects

This paper describes it method for monitoring electromigration (EM) resistance of multilayered metal interconnects which have been widely used in recent LSI technologies. We studied the combination of SWEAT (Standard Wafer-Level Electromigration Acceleration Test) patterns and the BEM (Breakdown Energy of Metal) method. We found that SWEAT pattern has a threshold length in its narrow portion to grow voids induced by EM, and optimized the conditions for the BEM method in terms of temperature and ramping rate. We have realized an in-process EM monitoring method which takes 4 minutes per sample at room temperature using the above combination.