Real dimensional simulation of SiO2 etching in CF4 + H2 plasma

Abstract

The two-dimensional modelling of the etching of silicon oxide in CF4+H2 plasma is considered. The profiles of etched trenches at real dimensions are calculated as a function of mask dimensions, concentrations of chemically active and non-active plasma components and ion bombardment parameters. The chemical composition of CF4+H2 plasma is calculated, the plasmochemical etching (PCE) and reactive ion etching (RIE) of a SiO2 in the plasma are investigated to achieve the goal. It was found that the aspect ratio and etching anisotropy decrease with increase of H2 content in the feed during SiO2 etching in CF4+H2 plasma. The concentration of CF radical is insufficient to passivate the sidewalls completely. Meanwhile, the formation and subsequent growth of fluorocarbon film stop etching during one-dimensional PCE of SiO2 at critical H2 content in the feed.