Etching characteristics of ArF and EUV resists in C₄F₆- and C₄F₈-based dual-frequency superimposed capacitively-coupled plasmas

In this study, we compared the etching characteristics of non-patterned ArF and extreme ultraviolet (EUV) resists in C₄F₆- and C₄F₈-based, dual-frequency superimposed, capacitively-coupled plasma (DFS-CCP) etchers. Different etch process parameters, such as the gas flow rate, highand low-frequency source power combinations (P_HF/P_LF), and high- and low-source frequency combinations (f_HF/f_LF) were used. The etch rates of the ArF and the EUV resists were increased significantly with increasing fHF and increasing C₄F₆ flow rate in the C₄F₆ plasmas. The resist etch rates were higher in the C₄F₆/Ar plasmas than in the C₄F₈/Ar plasmas due to the higher F radical density and lower CF_x polymerization on the resists in the C₄F₆/Ar plasmas. The etch resistance of the EUV resist was higher than that of the ArF resist due to the higher CF_x polymerization on the EUV resist.