Void growth in Al metallizations was investigated by correlating it with electrical resistance changes and with thermographically measured changes in the temperature distribution. It was found that a constant current which flowed through 2 interconnects (of differing widths), in series, consistently induced void growth at their junction. This could be observed, with high resolution, by means of infra-red and optical microscopy. The electrical resistance change which occurred as a result of electromigration directly reflected a local temperature change which resulted from void growth. A pulse phenomenon in the electrical resistance corresponded to a temperature increase of more than 200C around the void-growth area. This phenomenon was attributed to local melting which was induced by void growth, and to void healing after recrystallization of the adjacent Al grains.

S.Kondo, K.Ogasawara, K.Hinode: Journal of Applied Physics, 1996, 79[2], 736-41