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

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.