Ductile Au<inf>4</inf>Al intermetallic compound with crack resistance

Abstract

The Au–Al intermetallic compounds (IMCs) were commonly regarded as brittle within wire bonding interfaces. Here the in-situ micro-pillar compression tests of Au4Al IMCs were carried out to verify their intrinsic mechanical property. The result clearly shows that, surprisingly, the Au4Al IMC is ductile, while the yield stress appeared to be about 1 GPa. Furthermore, upon the compression tests of Au4Al IMC micro-pillars with initial crack, no brittle fracture was observed; instead, the plastic deformation of Au4Al was shown via shear band. This work suggests that pristine Au4Al IMC is ductile and crack-resistant, which provides new insights for wire bonding process and technology.