ANNEALING BEHAVIOR OF AL-Y ALLOY FILM FOR INTERCONNECTION CONDUCTOR IN MICROELECTRONIC DEVICES

Progress in patterning technologies and computer-aided circuit designs have brought us to the threshold of submicron dimensions in the fabrication of very large scale integrated circuits. For metallization at submicron dimensions, several requirements must be satisfied. In the present study we have prepared pure Al and Al-Y alloy films with different yttrium concentration by electron-beam evaporation and evaluated several annealing characteristics for the Al-Y/(100) Si system by using a transmission electron microscope, scanning electron microscope, and measuring the electrical resistivity. We found that in the Al-0.7 wt % (0.2 at. %) Y alloy film annealed above 300-degrees-C the electrical resistivity decreases to a value similar to that of a pure Al film, that is, 2.9-mu-OMEGA cm, and the same concentration of yttrium is also sufficient to minimize the generation and growth of annealing hillocks. These results are explained by the compositional and microstructural changes occurring in the Al-Y/(100) Si system.