Etch Characteristics of ZrO2Thin Films in High Density Plasma

In this work, we investigated the etching characteristics of ZrO2 thin film and the selectivity of ZrO2 thin film to Si in the HBr/CF4 high density plasma (HDP) system. The maximum etch rate of 70.8 nm/min for ZrO2 thin film was obtained at HBr (75%)/CF4 (25%) gas mixing ratio. At the same time, the etch rate was measured as functions of the etching parameters such as HDP source power, bias power and temperature. The angle-resolved X-ray photoelectron spectroscopy analysis showed an efficient destruction of the oxide bonds by the ion bombardment as well as an accumulation of low volatile reaction products on the etched surface. Based on these data, the ion-assisted chemical reaction was proposed as the main etch mechanism of ZrO2 for the CF4-containing plasmas.