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

Abstract

The dry etching of CoZrNb and CoTb magnetic thin films was carried out using Cl 2 and C 2 F 6 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 Cl 2 gas than in C 2 F 6 gas. The etch rates of CoZrNb and CoTb films were in the range of 30 ~ 60 nm/min for Cl 2 gas while in the case of C 2 F 6 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 Cl 2 gas increases, the etch slope became slanted. At the etch conditions used in this study, it is thought that the concentration of 20 ~ 40% Cl 2 /Ar gas is optimum to give fast etching and clean profiles.

Nanometer-sized etching of magnetic tunnel junction stack for magnetic random access memory

“…Since chlorine gas is known to be effective in etching of magnetic films, Cl 2 /Ar gas was selected as an etching gas for MTJ stack etching [4][5][6]. Also, among various hard masks such as SiO 2 , TiO 2 , TiN, metal films, TiN films showed slow etch rate.…”

“…Also, among various hard masks such as SiO 2 , TiO 2 , TiN, metal films, TiN films showed slow etch rate. Thus they were used as a hard mask in this study [6].…”

Etch characteristics of magnetic tunnel junction stack using a high density plasma in a HBr/Ar gas

“…Since magnetic materials rarely react with chemically active species in a plasma, it is known that dry etching of magnetic materials is hard to achieve [6][7][8]. At present, the etching of MTJ stack has been carried out using ion milling, chemical assisted ion etching (CAIE), reactive ion etching (RIE), and high density plasma reactive ion etching (ICPRIE) [3,5,6,9].…”

High-density plasma etching of CoFeSiB magnetic films with hard mask

“…In order to lessen these problems, high-density plasma etching of magnetic materials has been employed for the improvement of the etching process [3][4][5]. The reactive ion etching of CoFeSiB films was not reported yet, except the etching of CoFe films [6].…”