Electron Spectroscopy for Chemical Analysis Study on Influence of Polymerization on Anisotropic Etching of Thick Silicon Oxide Using C 2F 6 Based ECR-RIBE

Abstract
Anisotropic etching mechanism is investigated increasing the CF2 precursor in C2F6 plasma. The increasing of CF2 precursor is known from the ESCA (electron spectroscopy for chemical analysis) measurement of C/F elemental ratio of the deposited layer. It is found that the C/F ratio is increased from 0.28 to close to 1, when the microwave power of plasma is increased from 150 W to 350 W, respectively. The side wall angle of the deep SiO2 etching under the power of 350 W, is found to be close to 90°. The SiO2 etching selectivity with respect to the chromium (Cr) metal mask is also found to be enhanced considerably with the increasing of microwave power.