High-density plasma etching of cobalt thin films using C2H5OH/O2/Ar gas mixture

Abstract

In this study, Co thin films were etched using a C2H5OH/O2/Ar gas mixture via high-density plasma etching. As the concentrations of C2H5OH and O2 gases increased, the etch rate of the Co films decreased, whereas the etch profile improved. The addition of O2 to C2H5OH/Ar led to reduced redeposition on the sidewalls of the Co films. According to X-ray photoelectron spectroscopy and optical emission spectroscopy, the formation of Co(OH)2 compounds is critical for obtaining a redeposition-free etch profile, and CoOx may act as a reaction intermediate. Based on these findings, the C2H5OH/O2/Ar gas mixture can be used as a prospective etching gas in the etching of Co thin films.