Model-based analysis of the silica glass film etch mechanism in CF(4)/O(2) inductively coupled plasma

Abstract

The analysis of the Er-doped silica glass films (62%SiO(2)-30%B(2)O(3)-8%P(2)O(5) + 0.2 wt%. Er(2)O(3)) etch mechanism in the CF(4)/O(2) inductively coupled plasma was carried out using the combination of simplified models for plasma chemistry and etch kinetics. As the O(2) mixing ratio in the CF(4)/O(2) plasma increases from 0% to 30%, the etch rate decreases monotonically in the range of 385-190 nm/min that contradicts with the behavior of F atom density and flux. From the model-based analysis, it was found that, at low ion bombardment energies, the etch process followed the formal kinetics of ion-assisted chemical reaction and was controlled by both neutral and ion fluxes.