Etch characteristics of CoZrNb and CoTb magnetic thin films in a high density plasma

The dry etching of CoZrNb and CoTb magnetic thin films was carried out using Cl2 and C2F6 etch gases in an high density plasma. These new magnetic materials exhibited the etching characteristic of monotonous decrease in etch rate with increasing gas concentration. The etch rates of CoZrNb and CoTb films were faster in Cl2 gas than in C2F6 gas. The etch rates of CoZrNb and CoTb films were in the range of 30 ∼ 60 nm/min for Cl2 gas while in the case of C2F6 gas, CoZrNb and CoTb films showed the etch rate of less than 20 nm/min. The etch profiles of CoZrNb and CoTb films exhibited clean without any etch residues but the etch slopes were shallow. As the concentration of Cl2 gas increases, the etch slope became slanted. At the etch conditions used in this study, it is thought that the concentration of 20 ∼ 40% Cl2/Ar gas is optimum to give fast etching and clean profiles. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)