Suppress Copper Diffusion through Barrier Metal-Free Structure by Implantation of Nitrogen Atom into Low-K Material

Abstract

Currently, Cu and spin-on organic low-k polymer are the leading candidates for ultra-large-scale integrated circuits (ULSI) technology. A device integrated with low-k material and Cu film is capable of improving its performance. Serious degradation is induced in the device when Cu diffuses into the dielectric layer during post-heating and under an applied electric field. Methyl-phenyl silsesquioxane (MSQ), a spin-on organic low-k material, can successfully suppress Cu diffusion without using a barrier metal by implanting N into itself. The dielectric constant and barrier capability of MSQ film could further be improved by F and N co-implantation. A metal insulator semiconductor (MIS) capacitor structure was used in this study and it showed better barrier capability and lower leakage current after N and F were co-implanted into the low-k material.