CFX(X=1–3) Radicals Controlled by On-Off Modulated Electron Cyclotron Resonance Plasma and Their Effects on Polymer Film Deposition

Abstract

The CF, CF₂ and CF₃ radical and F atom densities and the polymerization were investigated in an on-off modulated CHF₃ electron cyclotron resonance plasma. Using infrared diode laser absorption spectroscopy, the remarkable changes of the CF _X (X=1–3) radical densities were observed by varying duty cycle at microwave powers of more than 300 W. The mechanisms of these behaviors of CF _X (X=1–3) radical densities were discussed on the basis of the results of the dissociation degree of the CHF₃ molecule. The polymer deposition rates on Si and SiO₂ surfaces were also investigated, and it was found that the CF₂ radical contributed greatly to the growth of polymer films. Furthermore, X-ray photoelectron spectroscopy measurement showed that the -CF₂ component in the polymer films decreased markedly and the -C-CF _X component increased as the CF₂ radical density in the plasma decreased.