Distinct modes in the evolution of interaction between polymer film and atmospheric pressure plasma jet

Different modes are revealed and characterized in the evolution of interaction between an atmospheric pressure He/O-2 plasma jet and the parylene-C film deposited on a silicon substrate. In the initial mode, the plasma jet spreads on the film surface with the etching process layer by layer from the top to the bottom of the polymer film. Transition mode occurs with sudden change of discharge and plasma characteristics . Then coupled mode dominated the interaction process with the plasma confined in the etched hole and advanced lap by lap from inner to outer domain in the radial direction. To copper substrate, the same distinct modes were also observed. However, to the glass substrate, only layer by layer etching process was observed.