Etching Surface Form Evaluation of LiNbO<sub>3</sub> Crystal in Plasma RIE

Abstract

Etching characteristic of LiNbO3 has been investigated using plasma RIE. Etch rate increased in propotion to the atomic weight of inert gas in CF4+inert gas(He, Ne, Ar, Kr, Xe) plasma. It was improved about 20 times in CF4+Xe plasma in comparison with wet process in HF aquaus solution. As etch time increased, etching surface form became rough in CF4+inert gas plasma. Simirally, as RF bias increased, same result was obtained. It is found that this surface roughness is caused by the increase of the substrate temparature by an ion bombardment effect and can be removed by cooling the substrate.