ETCH CHARACTERISTICS OF COFESIB MAGNETIC FILMS USING INDUCTIVELY COUPLED PLASMA REACTIVE ION ETCHING FOR MAGNETIC RANDOM ACCESS MEMORY

Abstract

ABSTRACT Inductively coupled plasma reactive ion etching of CoFeSiB magnetic thin films was studied in a Cl2/O2/Ar gas mix. The etch rate, etch selectivity and etch profile of this magnetic film were examined on varying gas concentration, coil rf power, gas pressure and dc-bias voltage. As the Cl2 gas increased, the etch rate monotonously decreased and etch residues decreased but etch slope was slanted. The use of the TiN hard mask gave rise to high selectivity of CoFeSiB to the TiN mask due to large decrease in etch rate of TiN in Cl2/O2/Ar gas mix. The addition of O2 into the gas mix led to the anisotropic etching of CoFeSiB films without the etch residues.