CVD-PVD aluminum process for DRAM applications

The integrated CVD-PVD Al process was successfully applied to a 4-gigabit DRAM process flow for the simultaneous formation of plugs and wires. The CVD-PVD Al film completely filled vias with the aspect ratio up to 10:1, and Al plugs showed lower via resistance compared with that of the conventional W plugs. Outgassing from the intermetal dielectric was critical to the complete via filling of CVD-PVD Al film, and the baking after via etch was effective for eliminating outgassing.