Relationship between copper concentration and stress during electromigration in an Al(0.25 at.% Cu) conductor line

The real-time strain and Cu concentration measurements during electromigration in an Al(Cu) conductor line was studied. Results from the measurement showed that small strains were developed over the downstream 30% of the conductor line, where the Cu concentration remained above 0.15 at.%. Defect mediated coupling between Al Cu diffusive flows was proposed as the cause for the counterflow of Al when the Cu concentration was above critical concentration as the mechanism by which Cu reduces the rate of electromigration damage in conductor lines.