Process steps impact on electrical and electromigration performances of dual damascene copper

The impact of IC fabrication process steps on electrical and reliability characteristics of dual damascene copper interconnects has been analyzed. It is demonstrated that thermal treatments could have a negative impact on electrical performances unless a suitable encapsulation step of copper lines is performed. Electromigration performances are also strongly affected by annealing and the role that impurities have in dominating the diffusion paths is evidenced by experiments on differently fabricated copper structures of various widths.