It was recalled that a common feature that was revealed by electromigration experiments on lines, using various high-resolution resistometric methods, was a monotonous non-linear resistance increase at the very beginning of high-current electromigration tests, and a decrease which occurred after the current was removed. These effects had been attributed to the establishment of a steady state of vacancy concentration, during and after electromigration. It was shown here that even small abrupt temperature steps, which always occurred at the beginning and end of electromigration tests, were triggering events for various, frequently-reversible, phenomena which contributed to non-linear resistance changes. The precipitation and dissolution of alloying elements appeared to be the most important phenomena. Abrupt temperature changes also caused a change in the hydrostatic stress of passivated lines. The relaxation of the hydrostatic stress could be coupled with a void-volume change, and the total resistance was a function of both the hydrostatic stress and the void volume. It was demonstrated, by experiment, that the effect of hydrostatic stress relaxation upon resistance variations was negligible in comparison to the effect of precipitation and dissolution. But such non-linear thermally-induced effects did not exclude the possibility of simultaneous resistance changes that were due to the accumulation or relaxation of electromigration damage.

A.Scorzoni, I.De Munari, H.Stulens, V.D’Haeger: Journal of Applied Physics, 1996, 80[1], 143-50