Electromigration-induced stress distributions in 200µ-long 10µ-wide conductor lines, in 1.5µ SiO2 passivation layers, were investigated by using synchrotron-based white-beam X-ray micro-diffraction techniques. The results showed that a steady-state linear stress gradient developed along the length of the line, and that this gradient could be controlled by the magnitude and direction of the current flow. On the basis of the current density dependence of the steady-state stress gradient, the effective valence was estimated to be 1.6 at 260C. From the time-dependence of the transient-state stress gradient, the effective grain-boundary diffusion coefficient was estimated to be equal to 8.2 x 10-11cm2/s at 260C by using Korhonen's stress evolution model. The effective valence and diffusivity values were in good agreement with previously reported data.

Electromigration-Induced Stress in Aluminium Conductor Lines Measured by X-Ray Micro-Diffraction P.C.Wang, G.S.Cargill, I.C.Noyan, C.K.Hu: Applied Physics Letters, 1998, 72[11], 1296-8