Decontamination of Co, Mo in SF6/O2 RF plasma

Metal surface processing using for plasma has been highlighted in nuclear industry because the dry decontamination method has been strongly recommended, satisfying the requirement of drastic secondary waste reduction while maintaining the same level of efficiency with current wet decontamination method. Important reaction of plasma decontamination is a fluorination between metal surface and fluorine gas and reactants from fluorination are volatile compounds which have very low melting temperature. DC bias or adding to inert gas (He, Ar, N2) with fluorination can highly increase reaction rate. In this paper, we experimented on SF6/O2 reaction rate with Mo, Co metal and compared with CF4/O2 results. It appears that SF6/O2 is more efficient than CF4/O2 about 2 times in etching rate (um/min)