Bidirectional electromigration failure

• We use electromigration model of Korhonen et al. with bidirectional current stress.
• Voids can nucleate, grow, shrink and heal as the electrical current reverses.
• Plastic effects caused by stress cycling is determined by line homogeneity.

Pulsed bidirectional currents in copper interconnect can cause electromigration (EM) –induced cyclic void behaviour. Cycles of void nucleation, growth, shrinkage and healing may be seen in the time variation of a line’s resistance profile. In practice each cycle appears to create some net effect so that, eventually, the net effect of many cycles adds up to the failure criterion. We seek here to investigate whether the Stress Evolutional Model of Korhonen et al. [1] is capable of describing the net effect of a voiding cycle.