PLASMA-DEPOSITED DIELECTRICS FOR CU METALLIZATION SYSTEMS

The interaction of copper with PECVD silicon oxynitride films was inve stigated by different analytical and electrical methods. Using AES-dep th profiling and RBS measurements, no copper diffusion in films invest igated was observed after applying a thermal stress of 450 degrees C f or 1 h. However, copper migration was detected after applying thermal and electrical stress simultaneously (BTS). C-V and I-V measurements b efore and after different BTS-conditions were performed on MIS-structu res with copper dots. The shift of the C-V curves resulting from coppe r migration decreases with an increasing N/O-ratio of SiOxNy films, de monstrating the better barrier properties of silicon nitride compared to silicon oxide. Additionally, the time to failure (TTF) was studied as a function of thermal and electrical stresses. Again, SiNx-samples achieved the highest TTF-values. The polarity dependence of the leakag e current suggests a Cu ion drift transport mechanism. (C) 1998 Elsevi er Science S.A.