Titanium carbide etching in high density plasma

Abstract

Titanium carbide etching in fluorine-containing (CF4, CHF3, and SF6) high density plasmas was investigated. The dependence of etch rates on gas composition and bias power was studied using the response surface method and the effects of source power and pressure were also examined. Argon was found to enhance the etch rate but the effect diminished when etching was controlled by the availability of the reactive species. The increase of the etch rate with increasing pressure indicated that the reactive radicals are the main etching species. The etch rate in SF6 plasma was found to be up to four times faster than in CF4 plasma because of the abundance of the active fluorine species. Electron spectroscopy for chemical analysis (ESCA) detected a carbon-rich surface layer for samples etched with CF4, CHF3 and even a non-polymerizing SF6 plasma. The results suggested that titanium was extracted preferentially from TiC during reactive ion etching in fluorinated plasmas.