Properties of Reactive Argon Plasmas at Atmospheric Pressure

Summary form only given. A new atmospheric pressure plasma source has been developed that shows exceedingly high processing rates. For example, kapton films have been etched at 5.0 mum/s using an argon and oxygen discharge with 6.0 vol.% O₂ and a temperature of 280degC. The plasma source consisted of a small quartz tube that was capacitively coupled to radio frequency power at 13.56 MHz. The input plasma power could be increased up to 150 W/cm³ without arcing, or forming a streamer like discharge. At this power density, the gas temperature was determined by spectroscopic methods to be 300plusmn30degC. The O atom concentration was measured in the plasma afterglow by nitric oxide titration, and was found to be 1.2plusmn0.6times10¹⁷ cm^-3 at 150 W/cm³ and 6.0 vol.% O₂ in Ar. The concentration of ozone in the downstream region equaled 4.3plusmn0.5times10¹⁴ cm ^-3, as determined by UV absorption spectroscopy. These results were found to be in good agreement with a numerical model of the plasma and afterglow that included the reaction mechanism and the plasma electron density and temperature as calculated from current-voltage measurements