A threshold pulse width for electromigration under pulsed stress conditions

Pulsed-current-induced electromigration failure was studied under various repetition frequencies and current densities. Self-joule-heating of the conductors during stressing was monitored directly by detecting the infrared intensity emitted from the conductor. It was found that there is a critical pulse width for electromigration under pulsed stress conditions which depend on the peak current density and substrate temperature. This fact suggests that a continuous force is needed to cause Al ions to migrate. When a pulse width is sufficiently short, Al ions cannot move and settle in new unstable sites