Preparation of Cu 10Zr 7 Intermetallic Compound Film and Its Application as a Diffusion Barrier in Cu/Cu 10Zr 7/ZrN/Si Contact System

Abstract

We investigated the diffusion barrier properties of Cu10Zr7 intermetallic compound film for possible application to Cu metallization technology. First, a Cu/Zr bilayered film was heat-treated in vacuum at various temperatures for 1h, to confirm the most stable Cu–Zr compound formed by solid-phase reaction. It was found that a single phase of Cu10Zr7 compound can be obtained at temperatures above 550°C and that this compound film is stable up to 600°C. On the other hand, by the co-sputtering method, although CuZr2–Cu10Zr7 mixture alloy film was prepared, no Cu10Zr7 single-phase compound film was obtained. We heat-treated the Cu/CuZr2–Cu10Zr7 bilayered film for 2h at 500°C, which was lower than the temperature necessary for the formation of Cu10Zr7 by solid-phase reaction. In this way, we prepared the stoichiometric Cu10Zr7 film. Then, we produced the Cu/Cu10Zr7/ZrN/Si contact system using this Cu10Zr7 film as a diffusion barrier and investigated its thermal stability. We found that the system is satisfactorily stable up to 650°C without any Si diffusion, although a slight diffusion of Cu was observed at the interface of Cu/Cu10Zr7.