Influence of temperature on the etching rate of SiO2 in CF4 + O2 plasma

The plasmochemical etching of SiO2 in CF4 + O2 plasma is considered. During the experiment SiO2 films are etched in CF4 + O2 plasma at temperatures of 300 and 350 K. The dependences of plasmochemical etching rates of SiO2 on O2 content in the feed are measured. The experimental measurements are compared with theoretical calculations. The obtained theoretical results are used to predict the real dimensions of etched trenches. It is found that decrease in temperature reduces lateral undercutting due to decreased desorption of formed SiF4 molecules from the sidewalls.