Cl2/CO를 이용한 백금박막의 화학적 건식식각 특성

Abstract

In this study, we have developed a novel method for Pt etching using chemical dry etching (CDE) system. Volatile etching product during chemical dry etching was formed during the reaction of Pt with Cl2 and CO. The etch rate was abruptly increased above 210 °C which corresponds to the sublimation temperature of platinum dicarbonyl chloride. The maximum etch rate was obtained at the mole ratio of Cl2 to CO of 1/2, which agrees with the stoichiometric ratio of Cl2 to CO to form platinum dicarbonyl chloride. The large enhancement in etch rate above 210 °C might be attributed to the formation of a volatile platinum carbonyl compound on Pt surface. Relatively high etch rate above 100 nm/min and high selectivity towards Pt of a few hundreds against sub-layers such as SiO2 and TiN were obtained at various etching conditions. Chemical analysis of the etched surface with XPS showed that surface Pt atom was converted to a volatile compound. XPS and SEM studies of Pt surface treated with Cl2 and/or CO indicated that volatile platinum carbonyl compounds were formed in the reaction of CO with Pt surface pre-treated with Cl2 above 210 °C.