Microtexture and electromigration-induced drift in electroplated damasceneCu

In this work, the electromigration (EM) performance of electroplated damasc ene Cu is investigated by drift experiments on Blech-type test structures i n both polycrystalline and bamboo microstructures. For the first, microtext ure data were obtained from electron backscatter diffraction as well. While both bonding areas and 10 mu m wide lines were found to have a predominant ly random grain orientation, the drift studies indicated the importance of strongly segregating impurities in controlling Cu grain-boundary EM. For th e bamboo lines, the impact of different barrier layers has been investigate d, comparing Ta, TaN, and TiN. Drift was shown to proceed in all cases at t he metallic Cu barrier interface, but faster for the Ta as compared to the TaN and TiN barriers. Cu drift data were finally compared to available lite rature results and to our previous drift studies on Al(Cu). (C) 2000 Americ an Institute of Physics. [S0021-8979(00)05806-0].