Comparative study of W-plug, Al-plug and Al-dual damascene for 0.18 /spl mu/m ULSI multilevel interconnect technologies

Comparative studies of W-plug, Al-plug and Al dual damascene were carried out for 0.18 /spl mu/m ULSI multilevel interconnects. The via resistance of Al dual damascene was one-fourth of that of W-plug. Al dual damascene interconnects were found to have misalignment tolerance. The electromigration lifetime of Al dual damascene was 4 times longer than that of conventional W-plug, even though lithography misalignment occurred between the vias and the trench wiring. We developed highly reliable Al dual damascene interconnect technology with 0.56 /spl mu/m pitch for 0.18 /spl mu/m design rule ULSIs.