Correlation of Plasma Erosion Resistance and the Microstructure of YF3 Coatings Prepared by Vacuum Kinetic Spray

To decrease the generation of contamination particles during semiconductor manufacturing processes, a plasma-erosion-resistant coating that can prevent particle dropout on the surface of the wafer etching chamber is required. In this work, correlation between plasma-erosion resistance and the microstructure of a YF 3 coating deposited by vacuum kinetic spray (VKS) was studied. The plasma-erosion resistance of the coatings was evaluated using inductively coupled plasma etching tests, and the microstructure of the coatings before and after the etching test was analyzed using field emission scanning electron microscope and transmission electron microscope. Via a simple heat treatment of the feedstock powder, YF 3 coatings with different deposition behaviors were prepared. As the heat treatment temperature of the feedstock powder was increased, the plasma-erosion resistance was improved. High-density YF 3 coatings had randomly oriented small crystallites induced by sufficient room-temperature impact consolidation. The adhesion strength of the coating was improved with higher heat treatment temperature, which contributed to significant reduction in particle dropout from the YF 3 coating. These results imply that the plasma-erosion resistance of YF 3 coatings formed by VKS can be controlled by coating characteristics such as crystallite size, porosity, roughness, and density.