Influence of via liner properties on the current density and resistance of vias

Reduced dimensional features have resulted in an increase in the resistance and the current density within vias and interconnects. The introduction of copper has partially addressed these problems. However in the case of an interconnect via the liner\´s resistivity is much higher than the via metal via and the presence of a liner can significantly affect the via\´s electrical properties. Thus a 3-dimensional Finite Element analysis of a via model is undertaken in this paper. The influence of the liner resistivity ρ_L, thickness t and the liner-via metal interface barrier (ρ_C2) on via resistance Rv and the current density are quantitatively determined for the first time. A number of the results are readily interpreted in terms of a "transfer length" Lt parameter for current flow from the liner sidewalls to the via plug