Abstract
Plasma etching characteristic of LiNbO3 has been investigated. Etch rate increased in propotion to the atomic weight of inert gas in CF4+inert gas(He, Ne, Ar) plasma. Etch rate increased by removing a mixing layer, such as LiF, by an ion bombardment effect in CF4+Ar plasma. As etch rate was extremely low in Ar+H2, it was understood that F radical is contributing to etching of LiNbO3. Etching profile of the surface of crystal by CF4+Ar+H2 plasma was remarkably smooth similar to the non-etched surface. An anisotropic etching that had a high aspect ratio could be materialized in CF4+Ar plasma. Futhermore, waveguide pattern that had a comparatively high aspect ratio and etching profile of the surface was smooth could be realized in CF4+Ar+H2 plasma.
