Resistance changes due to cu transport and precipitation during electromigration in submicrometric Al-0.5%Cu lines
In this work we describe the resistance changes due to Cu transport and precipitation during electromigration in 0.5/spl mu/m wide Al-0.5%Cu lines. A wafer-level, high resolution resistonietric technique allowed us to detect significant resistance drops during the initial phase of the electromigration test. TEM microstructural analysis and SEM observations were also performed. Large CuAI/sub 2/ aggregates were observed in the lines that underwent a high stressing current. The transport and coalescence of Cu atoms explains fairly well the observed resistance, drops, that are likely to be due to a decrease of the scattering events associated with tiny precipitates.