CuAl2 thin films as a low-resistivity interconnect material for advanced semiconductor devices

Abstract

New interconnect materials that have a low line resistivity are required to address issues associated with the increased resistivity due to the aggressive downscaling of future semiconductor devices. In this work, CuAl2 thin films are investigated as a potential material for liner- and barrier-free interconnect applications. The results show that CuAl2 blanket films adhere well to and do not undergo interdiffusion with SiO2, as well as having a favorable size effect of resistivity. Furthermore, the filling of CuAl2 in narrow low-k trenches is investigated, and an excellent gap-filling performance is registered. These features suggest that CuAl2 is a promising alternative to Cu that does not require any additional liner or barrier layers for feature sizes less than 10 nm.