Crystal Lattice Rearrangement Occurred at Au/Ag Bonded Interface in Atomic Diffusion Bonding in Vacuum

Abstract

The crystal lattice rearrangement which occurs at the bonded interface of two films during atomic diffusion bonding processing in vacuum was examined using Au and Ag films. Results revealed that remarkable crystal lattice rearrangement occurs at the bonded interface of Au−Ag bonded films at room temperature. Grains formed continuously across the original interface over the entire thickness of the bonded films. Also, the (111) preferred grain orientation was effective at enhancing the crystal lattice rearrangement. The crystal lattice rearrangement did not accompany remarkable interdiffusion of Au and Ag at the interface, even though the crystal lattice formed continuously across the original interface. In addition to crystal lattice rearrangement, grain boundary diffusion plays an important role in bonding processes, enhancing the interdiffusion between Au and Ag films. Grain boundary diffusion is likely to be effective to fill the gaps in the boundaries of grains formed by crystal lattice rearrangement.