REACTIVE ION ETCHING OF TA-SI-N DIFFUSION-BARRIERS IN CHF3-2(O)

Reactive ion etching of Ta36Si14N50 diffusion barrier layers was perfo rmed in CHF3+O-2 plasmas. Etch depths and rates were determined as a f unction of etch gas composition, cathode power, and etching time. Etch ing proceeds only after an initial delay which depends on gas composit ion and cathode power. This delay is attributed to the presence of a n ative surface oxide which must first be removed before etching can com mence. Maximum etch rate was attained at 62.5% O-2 concentration, whic h also corresponds to minimum delay.