CF₂ kinetics and related mechanisms in the presence of polymers in fluorocarbon plasmas

Laser-induced fluorescence was used to characterize the fluorocarbon plasma that was used to modify the wettability of hexatriacontane (HTC), a polymer model. The plasma volume downstream from a microwave plasma source was examined by monitoring the CF₂ concentration as well as the CF₂ decay rate (in the afterglow of a pulsed discharge) during treatment of the polymer surface (in 20-100 mTorr CF₄). In parallel, the behavior of F atoms was monitored by means of actinometric optical emission. Pulsed modulation of the discharge allowed the effects of variations in the loss and production rates for CF₂ to be distinguished, in the presence of hexatriacontane. Our observations are consistent with enhanced production of CF₂, possibly by an ion-assisted surface mechanism, in the presence of HTC.