Application of MoSi/sub 2/ to the Double-Level Interconnections of I/sup 2/L Circuits

A new MoSi/sub 2/-CVD-Al double-level interconnection system is developed to obtain a high packing density in I/sup 2/L circuits. Taking advantage of MoSi/sub 2/, a fine pattern consisting of a Iinewidth of 2.5 /spl mu/m aid a spacing of 1 /spl mu/m is achieved for the first-level interconnections. This new system has a higher reliability than the normaf Al-CVD-Al structure because of the stability of the MoSi2 surface. The fundamental properties of 1/sup2/L gates with MoSi2 interconnections, namely, gain, propagation delay time, and toggle frequency of a T flip-flop, are measured. At practical injector currents, they show nearly the same values as with Al interconnectiorm The resistance effects of MoSi/sub 2/ interconnections are calculated with regard to the unbalance of the injector currents and increase of the propagation delay time. The calculations show that these effects can be ignored at an injector current of 1 /spl mu/A/gate. At higher injector currents, the MoSi/sub 2/ interconnection resistance must be taken into account in I/sup 2/L pattern layout.