Realization of Cu(111) Single-Oriented State on SiO₂ by Annealing Cu–Zr Film and the Thermal Stability of Cu–Zr/ZrN/Zr/Si Contact System

We investigated whether the Cu(111) single-oriented state having excellent electromigration resistance could be realized on SiO₂/Si and Si wafers by annealing Cu–Zr alloy films in vacuum. It was revealed that the Cu(111) single-oriented state could be realized on both substrates of SiO₂/Si and 7059 glass, when Cu–Zr films were annealed at 500°C for 5 min. The obtained resistivities of the Cu–Zr films after annealing above 400°C were lower than those (3–3.5 µΩcm) of Al alloy systems. Next, we examined the thermal stability of the Cu–Zr/ZrN/Zr/Si contact system, and compared it with that of the Cu/ZrN/Zr/Si system. As a result, although the thermal stability of the former was somewhat inferior to that of the latter, the system was sufficiently stable up to 550°C, maintaining the single-oriented state of the Cu(111) overlayer and the ZrSi₂ region with the lowest contact resistivity at the Si interface.