Increase in electromigration resistance by enhancing backflow effect

The backflow effect on electromigration has been studied in terms of experiment and theory. The difference of electromigration resistance between the two materials Al-2%Cu/Ti and the stress gradient caused by a discontinuous SiO/sub 2/ overcoating layer were used to enhance the backflow intentionally to restrain the electromigration and improve the lifetime of metallization. A theoretical model is proposed to explain the formation of backflow. >