Influence of Grain Size Distributions on the Resistivity of 80 nm Wide Cu Interconnects

Abstract

The grain length distributions in the longitudinal direction of 80 nm wide Cu interconnects as a function of interconnect height and grain size influence on the resistivity have been investigated. Cu interconnects with 300 nm and 500 nm height had very similar average grain lengths when the trench depth was less than 260 nm, while for the 500 nm high Cu interconnect, larger grains were dominant when the trench depth was above 260 nm. Resistivity of the 80 nm wide Cu interconnect with 500 nm height was 10% lower than that for the 300 nm high interconnect.