Smooth and Vertical Profile Dry Etching of Si Using XeF₂ Plasma

Abstract

We demonstrated the discharge of XeF2 plasma and investigated the dry etching process of Si using XeF2 plasma. A vertical etching profile and a smooth etched surface, which satisfy the requirements for optical device fabrication, were obtained. The etching rate of Si was 0.7 µm/min at 1 Pa and 100 W. It was found that the RF power dependences of the emission intensities of Xe, F, and XeF were similar to that of the etching rate of Si. The etching rate ratio of Si to SiO2 in the XeF2 plasma etching process was approximately 10, which was much larger than that in the CF4/O2 plasma etching process. We believe that XeF2 plasma etching is a very simple and useful process for Si-based optical devices such as photonic crystals, narrow optical waveguides, and micro-electro-mechanical systems (MEMS) device fabrication.