A comparison was made between the local crystallographic orientations, that were associated with stress voids in Al-1Si-0.5wt%Cu, and those in pure Cu interconnects. The orientations were graded by whether grains were immediately adjacent to voids. Grains which were adjacent to voids in Al-Si-Cu exhibited a <111> fibre texture that was slightly clearer than those in intact regions. This contrasted with the case of Cu, which exhibited a weaker local (111) texture around voids. It was suggested that the difference was due to the relative effectiveness of the diffusion paths available in the lines. In Al-Si-Cu, the presence of defects which were associated with precipitates could permit rapid diffusion than grain boundaries. Voiding in Cu, which was free from such defects, depends more on grain boundary structure.

Local Crystallography and Stress Voiding in Al-Si-Cu versus Copper Interconnects. R.R.Keller, C.E.Kalnas, M.Phelps: Journal of Applied Physics, 1999, 86[2], 1167-72