Plasma etching of titanium disilicide

Refractory metal silicides are being increasingly considered as an alternative to polysilicon for the gate interconnection level in MOS VLSI. In this context the etching of titanium disilicide in chlorine based plasmas has been investigated. Carbon tetrachloride plasmas excited at 100 kHz are shown to produce anisotropic edge profiles but with silicide to oxide selectivities of about 7:1. Chlorine plasmas were found to be more selective to oxide but were also found to cause undercutting of the resist mask.