Characteristics of copper films deposited on H2-plasma-treated TaN substrate by chemical vapor deposition

Abstract

This work investigates the chemical vapor deposition Cu films deposited on the TaN substrate with and without an H2-plasma treatment prior to Cu film deposition and the effect of postdeposition thermal annealing. The Cu films deposited on the H2-plasma-treated TaN substrate have a number of favorable properties over the films deposited on the TaN substrate without the plasma treatment. These include an increased (111)-preferred orientation, smoother film surface, and a larger effective deposition rate. However, the Cu films deposited on the H2-plasma-treated substrate have a higher electrical resistivity, presumably due to the smaller grain size. The postdeposition thermal annealing enhanced the (111)-preferred orientation and decreased the resistivity of the as-deposited Cu films. We presume that the H2-plasma treatment, resulted in a dense and uniform distribution of hydrogen radicals adsorbed on the substrate surface, leading to the shortening of incubation time and the formation of Cu films with a smoother surface and enhanced (100)-preferred orientation. A combined process including H2-plasma substrate treatment prior to Cu film deposition and postdeposition thermal annealing at an appropriate temperature in N2 ambient, is proposed for the advantage of low-resistivity and high (111)-oriented Cu film deposition.