Quantitative Characterization of Dislocation Structure coupled with Electromigration in a Passivated Al (0.5wt% Cu) Interconnects R.I. Barabash 1 , N. Tamura 2 , B.C. Valek 3 , R. Spolenak 4 , J.C. Bravman 3 , G.E. Ice 1 and J.R. Patel 2 1 Metals & Ceramics Divisions, Oak Ridge National Laboratory, Oak Ridge TN 37831 2 Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley CA 94720 3 Dept. Materials Science & Engineering, Stanford University, Stanford CA 94305 4 Max Planck Institut für Metallforschung, Heisenbergstrasse 3, D-7056 Stuttgart, Germany ABSTRACT New synchrotron x-ray microbeam methodology is used to analyze and test the reliability of interconnects. The early stage of plastic deformation induced by electromigration before any damages become visible has been recently revealed by white beam scanning X-ray microdiffraction during an accelerated test on Al interconnect lines. In the present paper, we provide a quantitative analysis of the dislocation structure generated in several micron-sized Al grains in both the middle region and ends of the interconnect line during an in-situ electromigration experiment. We demonstrate that the evolution of the dislocation structure during electromigration is highly inhomogeneous and results in the formation of randomly distributed geometrically necessary dislocations as well as geometrically necessary boundaries. The orientation of the activated slip systems and rotation axis depends on the position of the grain in the interconnect line. The origin of the observed plastic deformation is considered in view of constraints for dislocation arrangements under applied electric field during electromigration. The coupling between plastic deformation and precipitation in the Al (0.5% wt. Cu) is observed for the grains close to the anode/cathode end of the line. INTRODUCTION The decrease of interconnect lines dimensions with a simultaneous increase in current density to 1 MA/cm 2 has imposed tremendous challenges for materials and reliability of interconnects. Electromigrationdepletes material at the cathode end of the interconnect line and causes accumulation near the anode end 1 . Electromigration-induced failure in metal interconnect constitutes a major reliability problem in the semiconductor industry 2 . While the general mechanism of electromigration is understood 3 , the effect of the atomic flow on the local metallic line microstructure is largely unknown. White beam X-ray microdiffraction 4-14 was used to probe microstructure in interconnects 4,11-14 and has recently unambiguously unveiled the plastic nature of the deformation induced by mass transport during electromigration in Al(Cu) lines 15 even before macroscopic damage occurs. The first quantitative analysis of dislocation structure in a grain in the polycrystalline region of the interconnect line was performed in 16,17 and it was shown that E1.2.1 Mat. Res. Soc. Symp. Proc. Vol. 766 © 2003 Materials Research Society