Radical Behavior in Fluorocarbon Plasma and Control of Silicon Oxide Etching by Injection of Radicals

In SiO2/Si selective etching processes using fluorocarbon plasmas, surface reactions of fluorocarbon radicals can affect the etching selectivity considerably. Therefore, information on radicals in plasmas and their surface reactions must be obtained. We developed an in-situ method of measuring various radicals in plasmas using infrared diode laser absorption spectroscopy (IRLAS) and have clarified the behaviors of the CF x (x=1–3) radicals in fluorocarbon plasmas for the first time. Moreover, we recently developed techniques of radical injection into plasma (RIT) and clarified the important radical in the plasma etching process. It is expected that these advances will contribute to the further developments in the semiconductor process field.