The Use of Inductively Coupled CF4/Ar Plasma to Improve the Etch Rate of ZrO2 Thin Films

In this study, we carried out an investigation of the etching characteristics (etch rate, and selectivity to SiO2) of ZrO2thin films in a CF4/Ar inductively coupled plasma (ICP) system. The maximum etch rate of 60.8 nm/min for ZrO2thin films was obtained at a 20 % CF4/(CF4+Ar) gas mixing ratio. At the same time, the etch rate was measured as afunction of the etching parameter, namely ICP chamber pressure. X-ray photoelectron spectroscopy (XPS) analysisshowed efficient destruction of the oxide bonds by the ion bombardment, as well as an accumulation of low volatilereaction products on the etched surface. Based on these data, the ion-assisted chemical reaction was proposed asthe main etch characteristics for the CF4-containing plasmas.