Preparation and Plasma Etching Resistance of Yttrium Oxide-Yttrium Oxyfluoride Composite Coatings

As the number of etching cycles continues to increase, conventional yttrium oxide (Y2O3) coatings can no longer meet the rigorous demands of advanced−node etching machines. Yttrium oxyfluoride (YOF) exhibits a lower etching rate under fluorine radical erosion compared with Y2O3; incorporating YOF into Y2O3 coatings therefore provides an effective approach to mitigating plasma erosion. In this study, three types of yttrium−based spherical powders (Y2O3-YOF, YOF, and Y5O4F7) were prepared by combining a solid-state reaction method with spray granulation. These were subsequently used to fabricate Y2O3-40 vol.% YOF, Y2O3-60 vol.% YOF, and pure YOF coatings via atmospheric plasma spraying (APS), with a pure Y2O3 coating serving as the control. CF4/Ar plasma etching experiments revealed that the surface maximum local erosion depth and the changes in surface roughness (before and after etching) of all three YOF-containing coatings were lower than those of the pure Y2O3 coating. Notably, the Y2O3-40 vol.% YOF coating, with its lower YOF doping level, exhibits the lowest value of maximum local erosion depth (59.3 nm) and minimal roughness variation among the tested samples. Although excessive YOF incorporation produced relatively high porosity, EDS and XPS analyses indicated that an optimal YOF doping level significantly suppresses the formation of new fluorinated products during etching. Overall, the Y2O3-40 vol.% YOF coating demonstrates high structural stability against both chemical fluorination and physical impact, suggesting its suitability for application in next-generation etching equipment.