It's the Y₂O₃ coating technology on Quartz surface.
The coating thin film, Y₂O₃ is transparent.
With this coating film,
it is possible to protect Quartz surface from Plasma Damage & Plasma Attack.


Fig. Cross-Sectional view of Y₂O₃ coating Fig. Plasma etched (a) Y₂O₃ and (b) quartz glass on quartz glass substrate.


Fig. SIMS analysis results for Y₂O₃


Fig. Performances of Y₂O₃ coating