Liner schemes of the aluminum damascene interconnection for sub-0.2 μm line pitch metallization

Abstract

We investigate the effects of liner scheme on the line and via resistances of aluminum damascene interconnects. The lowest line (∼0.19 Ω/sq. at 0.20 μm trench width) and via (∼0.5 Ω/via at 0.35 μm diameter) resistances are obtained at each different liner schemes of 30 nm TiN/20 nm Ti and 50 nm Ti-only, respectively. An optimized liner scheme of 10 nm TiN/40 nm Ti is therefore proposed. This scheme minimizes the TiAl 3 formation due to the interfacial reaction between the Al and the TiN, and produces the most satisfactory resistances of the line (∼0.24 Ω/sq. at 0.2 μm trench width) and the via (∼0.9 Ω/via at 0.35 μm diameter), respectively.