Mechanical Properties of Thin Al Wires Prepared by Electromigration

Abstract

Thin Al wires with diameters of 1 to 2 µm were fabricated by electromigration by applying a current in high density to a polycrystalline Al line containing a gap and a small hole in the oxide layer used to coat the line. The fabricated Al wires were subjected to small-span bending tests under observation with a microscope, and Young's modulus and yield stress of the wire were successfully determined. The value of Young's modulus of the thin Al wire was close to that of bulk Al. On the other hand, the yield stress of the Al wire was 20 times larger than that of bulk Al. The results of structural and elemental analyses of the wire showed that pure, single-crystalline Al was obtained by electromigration. Recrystallization during wire growth might be the mechanism through which this unique crystalline structure was obtained.