The effect of plasma treatment and a dielectric diffusion barrier on electromigration (EM) performance was examined. The characteristics and adhesion properties at the interface between copper (Cu) and the dielectric diffusion barrier were also investigated by scanning transmission electron microscopy–electron energy loss spectrometry (STEM–EELS). The existence of oxygen at the interface after hydrogen (H2) plasma treatment, which has a large pre-exponential factor, causes a large EM drift velocity. Ammonium (NH3) plasma treatment can reduce the Cu oxide completely, resulting in an improvement in EM performance. On the other hand, the dielectric diffusion barrier of SiCxNy, which has a better adhesion property then SiCx, reduces EM drift velocity and provides a larger activation energy. The reduction of CuOx completely by plasma treatment is essential and the selection of dielectric diffusion barrier is important to improve the EM performance of Cu damascene interconnects.
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