Characterization of Ru thin films from a novel CVD/atomic layer deposition precursor “Rudense” for capping layer of Cu interconnects

Abstract

The authors have succeeded in development of a novel Ru precursor, Ru(EtCp)(η5-CH2C(Me)CHC(Me)O) [Rudense], for CVD and atomic layer deposition (ALD) processes under nonoxidative condition. Rudense has sufficient vapor pressure and good thermal stability (decomposition temperature = ca. 230 °C). Ru thin films were grown on Pt, Ru, Si, and SiO2 substrates using Rudense and NH3 as Ru precursor and reactant, respectively. Rudense gave the conformal, low-impurity (<1021 atoms/cc), and low-resistivity (16 μΩ cm) Ru thin films. Moreover, Rudense showed substrate selectivity; therefore, Rudense will be a candidate for area-selective CVD and ALD precursor for Ru capping layers of Cu interconnects.