A Method for Copper Film Deposition with Cl2 Plasma

This study introduces a method for copper film growth with Cl 2 plasma. The method consists of two stages: generation of the precursor, CuCl, by etching a bulk copper target, and reduction of CuCl adsorbed on a substrate surface. In both reactions, atomic chlorine (Cl*) generated from the same Cl 2 plasma played the leading role. Copper films were grown on a TaN film (50 nm) adhesively at a growth rate of 118 nm/min. The obtained copper films had a resistivity of 2.0 μΩ cm and a Cl content of less than 15 ppm. This method also makes it possible to fill the 0.1 μm gap with an aspect ratio of 10.