Etching profile of silicon carbide in a NF_3/CH_4 inductively coupled plasma

摘要

Using a Ni mask as the protective layer, silicon carbide (SiC) has been etched in a NF_3/CH_4 inductively coupled plasma. SiC profiles were investigated as a function of process parameters. Experimental ranges are 700-850 W source power, 50-150 W bias power, 6-16 mTorr pressure, and 20-100% NF_3 percentage. Etch mechanisms were estimated by combining dc bias, etch rate, and expected fluorine radical behavior. The profile angle behavior with the bias power was mainly attributed to enhanced mask erosion by ion bombardment. The profile angle was strongly correlated to the dc bias in the source power range 700-800 W, and in the pressure range 7.5-10.5 mTorr. For the variations in the NF_3 percentage, the dc bias effect was insignificant.