Electromigration-Induced Morphology of 70 nm Al-Cu and Al Lines

Abstract

Al-Cu and pure Al bamboo lines 70 nm wide were stressed in situ in a high-resolution field emission scanning electron microscope at 275-282°C with a current density of All the lines underwent substantial changes induced by electromigration. Bump growth in both Al-Cu and pure-Al lines was observed in real time. In Al-Cu samples, narrowing of line segments occurred in all lines on the downwind side, and sequences of bump growth and shrinkage within groups indicated interactions among nearby bumps. Bumps in pure Al developed earlier and became larger than in Al-Cu lines, and bumps in both groups tended to curl upwind (toward the cathode). The data are consistent with material transport dominated by diffusion along the interfaces between Al and its surrounding dielectric. © 2003 The Electrochemical Society. All rights reserved.