AVS 66th International Symposium & Exhibition
    Plasma Science and Technology Division Monday Sessions
       Session PS+AS+EM+SS+TF-MoA

Plasma Resistance of Sintered Yttrium Oxyfluoride (YOF) with Various Y, O, and F Composition Ratios

Monday, October 21, 2019, 2:00 pm, Room B130

Session: Plasma-Surface Interactions
Presenter: Tetsuya Goto, Tohoku University, Japan
Authors: T. Goto, Tohoku University, Japan
Y. Shiba, Tohoku University, Japan
A. Teramoto, Tohoku University, Japan
Y. Kishi, Nippon Yttrium Co., Ltd, Japan
S. Sugawa, Tohoku University, Japan
Correspondent: Click to Email

Yttrium oxyfluoride (YOF) has been received much attention as the material for various functional components used in the plasma process chamber for semiconductor manufacturing. This is because, as compared to the widely used Y2O3, YOF is stable against various corrosive plasmas using halogen gases which is frequently used in the etching processes and/or chamber cleaning processes. We have reported that YOF (1:1:1) film has the higher resistance to various plasma conditions (N2/Ar, H2/Ar, NH3/Ar, NF3/Ar, O2/Ar) than the Y2O3 and YF3 films 1, 2. In this presentation, we report the effect of ion bombardment on the surface structure of sintered yttrium oxyfluoride (YOF) with various Y, O, and F composition ratios. By combining the starting materials of YOF, Y5O4F7, and YF3 in sintering, the YOF samples with different Y, O, and F composition ratios were prepared. In these samples, the oxygen composition ratio was changed from 33 at% to 7at%. According to this, the fluorine composition ratio was changed from 33at% to 66at%, and thus, the samples became from Y2O3 rich to YF3 rich. Ar ion beam with 500 eV was irradiated to these YOF samples. It was found that the sputtering etching rate was monotonically decreased as the oxygen composition ratio was decreased. It was also found that the surface roughness was relatively smaller for the samples with the composition ratios of Y:O:F=1:1:1 and 5:4:7 (both correspond to the stable composition) than those with other composition ratios. The results indicated that the atomic composition ratio is an important parameter to obtain YOF with good stability against plasmas.


The plasma irradiation and inspection were carried out in Fluctuation-Free-Facility in Tohoku University.

1. Y. Shiba, A. Teramoto, T. Goto, Y. Kishi, Y. Shirai and S. Sugawa, J. Vac. Sci. Technol. A, 35 (2), 021405 (2017).

2. A. Teramoto, Y. Shiba, T. Goto, Y. Kishi and S. Sugawa p. 16, AVS 65th International Symp., Long Beach, 2019.