Effectively blocking copper diffusion at low-k hydrogen silsesquioxane/copper interface

Abstract

The interaction between copper and low-k hydrogen silsesquioxane (HSQ) film was investigated using a Cu/HSQ/Si metal insulation semiconductor capacitor and hydrogen plasma posttreatment. Owing to serious diffusion of copper atoms in HSQ film, degradation of the dielectric properties are significant with the increase of thermal stress. By applying hydrogen plasma treatment to the HSQ film, however, the phenomena of serious Cu penetration were not observed by electrical characteristic measurements and secondary ion mass spectroscopy (SIMS) analysis even in the absence of diffusion barrier layers. Therefore, hydrogen plasma treatment can effectively block the diffusion of copper in low-k HSQ film.