Real-Time Tem Studies of Electromigration in Submicron Aluminum Runners

Abstract

Direct real-time observations of electromigration (EM) in submicron Al interconnects were made using a special sample-stage which allowed TEM observations to be recorded while simultaneously heating and passing current through the sample. The samples consisted of 4000Å thick Al(0.5wt%Cu) patterned over a TEM-transparent window into five runners in parallel, with linewidths 0.2, 0.3, 0.5, 0.8, and 1.0μm. Both passivated and unpassivated samples were examined. A current density of 2 x 106A/cm2 was used with temperatures ranging from 200 - 350°C. The experiments were done using constant voltage testing, and we used a special sample design which dramatically minimized Joule-heating. Our approach has allowed us to directly observe voids form, grow, migrate, pin, fail a runner, and heal, all with respect to the detailed local microstructure of the runners.

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Riege, S.P., Hunt, A.W. & Prybyla, J.A. Real-Time Tem Studies of Electromigration in Submicron Aluminum Runners. MRS Online Proceedings Library 391, 249 (1995). https://doi.org/10.1557/PROC-391-249

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