Low temperature deposition of metal films by metal chloride reduction chemical vapor deposition

Tantalum nitride, titanium, and iridium films were deposited at lower than 300 °C temperature by metal chloride reduction chemical vapor deposition (MCR-CVD) method using Cl2 plasma and respective metal targets. These results demonstrated features of MCR-CVD method: (1) The N/Ta ratio in the tantalum nitride films can be controlled by gas flow ratio of N2 to Cl2, (2) Conformal coverage to bottom-up filling via holes can be changed by substrate temperatures, (3) Deposition of iridium films needs protecting layers against damages by chlorine radicals (Cl*). We discuss the deposition mechanism of MCR-CVD as a system including depositing and etching, which are competitive to each other.