In this study, the CoFe thin film was studied using an inductively coupled plasma system in CH4-based gas chemistries. The etch rate of the CoFe thin film was systemically studied by the process parameters including the gas mixing ratio, the rf power, the dc-bias power, and the process pressure. The best gas composition for etching was in CH4 (20%)/Ar (80%) ratio. As the rf power and the dc-bias voltage were increased, the etch rate of the CoFe thin film increased in a CH4/Ar inductively coupled plasma system. The best process pressure condition for etching was 10 mTorr in the CH4/Ar inductively coupled plasma system. The changes in the components on the surface of the CoFe thin film were investigated with energy dispersive x ray.