Influence of Oxygen Additions on the Etch Characteristics of TaN Thin Films in CF4/Ar Plasma

TaN thin film was etched by O-2/CF4/Ar plasma. The TaN etching rate and the selectivity of etching TaN thin film relative to SiO2 and photoresist (PR) were investigated as functions of the gas mixing ratio. The maximum etch rate of TaN thin film was 158.1 nm/min in O-2/CF4/Ar (3:10:10 sccm) plasma. Evidence indicated that the mechanism of TaN etching is the breaking of the Ta-N bonds by Ar+ sputtering and subsequent chemical reaction of Ta with O radicals.