Measurements of CF2 radicals in CF4 and CF4/H2 electron cyclotron resonance plasmas

The CF2 radical density in a CF4 electron cyclotron resonance plasma is measured in terms of the microwave power, the pressure, the flow rate, and the H-2 addition ratio by using mass spectroscopy and optical emission spectroscopy. In mass spectroscopy, the CF2 radical density is measured by correcting the ionization and the dissociation processes with the mass spectrometer, and the results are compared with those from optical emission spectroscopy. The number of CF2 radicals increases with increasing power and saturates above 600 W, which means that the power is moved to other radicals. The CF2 radical emission intensity increases with the CF4 gas pressure and has a peak at 0.7 mTorr. When H-2 is added to CF4 + H-2, the CF2 radical emission intensity has a peak at a H-2 to CF4 + H-2 mixing gas ratio of 50 %.