Diffusion bonding of silver balls to a copper substrate and vice versa

Abstract

Small balls of pure silver (copper) placed on a single crystal substrate of copper (silver), as well as pairs of silver and copper balls kept in contact by gravity, were annealed at temperatures close to the eutectic temperature. Some aspects of the Ag Cu interphase boundaries which form were examined and 105 relative orientations of both phases were measured from Laue back reflection or Kossel patterns. These orientations are classified conveniently in terms of disorientations of the silver lattice with respect to the copper lattice. The disorientations are treated firstly in terms of a random distribution of the relative orientations of both lattices, and secondly in terms of a model where the lattices are oriented in such a manner that they have non-primitive near-coincident cells. The model allows the computation of theoretical disorientations corresponding to such relative orientations and gives results in agreement with some of the experimental disorientations.