Anelasticity study on electromigration effect in Cu thin films

[摘要] Electromigration (EM) tests on Cu thin film circuits below or near 373 K with the current density between 1 x 10(9) A/m(2) and 8 x 10(9) A/m(2) were carried out by means of the composite vibrating reed method. The resonant frequency (f) and the internal friction (Q(-1)) of the composite reed and the resistivity (R) of the thin film circuit were measured during isothermal EM tests for as deposited Cu/Ta films, Cu/Ta films annealed at 450 K and as deposited Ta/Cu/Ta films. An increase in f, a decrease in Q(-1) and a decrease in R were commonly observed. The activation energies found for the EM process (E-EM) range between 0.21 and 0.41 eV for the as deposited Cu/Ta films, between 0.21 and 0.59 eV for the annealed CUM films and around 0.3 eV for as deposited Ta/Cu/Ta films. It is suggested that a previously unrecognized mass transport process with low E-EM operates in these Cu thin films. (c) 2006 Elsevier B.V. All rights reserved.

[发布日期] 2006-12-20

[效力级别]  Proceedings Paper

[关键词] electromigration;Cu interconnects;Young's modulus;internal friction