RESISTANCE CHANGES DUE TO CU TRANSPORT AND PRECIPITATION DURING ELECTROMIGRATION IN SUBMICROMETRIC AL-0.5-PERCENT-CU LINES

In this work we describe. the resistance changes due to Cu transport a nd precipitation during electromigration in 0.5 mu m wide Al-0.5%Cu li nes. A wafer-level, high resolution resistometric technique: allowed u s to detect significant resistance drops during the initial phase of t he electromigration test. TEM microstructural analysis and SEM observa tions were also performed. Large CuAl2 aggregates were observed in the lines that underwent a high stressing current. The transport and coal escence of Cu atoms explains fairly well the observed resistance drops , that are likely to be due to a decrease of the scattering events ass ociated with tiny precipitates. Copyright (C) 1996 Elsevier Science Lt d