Stable yttrium oxyfluoride used in plasma process chamber

An yttrium oxyfluoride (YOF) protective material was developed for the inner wall of plasma process equipment. Using microwave-excited surface-wave high-density plasma equipment, the chemical stability of the obtained YOF films was evaluated by exposure to H2/Ar, N2/Ar, NH3/Ar, O2/Ar, and NF3/Ar plasmas. The YOF film surface was stable against these plasmas containing hydrogen, nitrogen, oxygen, and fluorine. Especially, the stability of YOF against fluoridation was better than that of Y2O3, which is currently widely used as the protective material in plasma process chambers.