De. Grosjean et H. Okabayashi, 1-D MODEL OF CURRENT DISTRIBUTION AND RESISTANCE CHANGES FOR ELECTROMIGRATION IN LAYERED LINES, I.E.E.E. transactions on electron devices, 44(5), 1997, pp. 744-750
We present a one-dimensional (I-D) analytical model incorporating cont
act resistance to calculate the current distribution between an Al lin
e and refractory metal underlayer in a drift velocity measurement stru
cture for electromigration. The current profile so calculated is more
accurate than the usual assumption that the current all flows in the A
l portion, and it should give a more accurate and reliable relation be
tween drift velocity and current density. It should also be useful in
correlating local current density with voiding, Various experimentally
observed voiding processes are included in the model; they reproduce
and predict different types of changes in total line resistance, most
notably the step structure observed in electromigration.