IEEE Electron Device Letters

Line Resistance Reduction in Advanced Copper Interconnects

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Line resistance reduction in interconnects was achieved through Cu microstructure modulation. The modulation was performed via both raising annealing temperature and reducing the post-patterning dielectric aspect ratio and resulted in a bamboo-like Cu microstructure. Compared with the conventional polycrystalline, the modulated Cu microstructure also presents a lower resistivity increase rate with area scaling. A TaN stress control layer deposited on over-plated Cu surface was demonstrated to be critical for maintaining the Cu interconnect integrity after the high-temperature anneal.