Characteristics of copper films deposited on H(2)-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 H(2)-plasma treatment prior to Cu film deposition and the effect of postdeposition thermal annealing. The Cu films deposited on the H(2)-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 H(2)-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 H(2)-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 H(2)-plasma substrate treatment prior to Cu film deposition and postdeposition thermal annealing at an appropriate temperature in N(2) ambient, is proposed for the advantage of low-resistivity and high (111)-oriented Cu film deposition. (C) 2002 American Vacuum Society.