Dry Etching of ITO Thin Films by the Addition of Gases in Cl2/BCl3 Inductivity Coupled Plasma

In this study, we investigated the etching characteristics of ITO thin films and the effects of inert gases added to Cl2/BCl3 inductivity coupled plasma. The maximum etch rate of ITO thin film was 130.0 nm/min upon the addition of Ar(6 sccm) to the Cl2/BCl3 (4:16 sccm) plasma, which was higher than that with He or N2 added to the plasma. The ionbombardment by Ar+ sputtering was due to the relatively low volatility of the by-products formed in the Cl2/BCl3 (4:16sccm) plasma. The surface of the etched ITO thin film was characterized by x-ray photoelectron spectroscopy (XPS)and atomic force microscopy (AFM). From the XPS results, it is concluded that the proper addition of Ar and He to theCl2/BCl3 plasma removes carbon and by-products from the surface of the etched ITO thin film.