Local deposition of plasma-polymerized films at atmospheric pressure

Abstract

Recently reported progress regarding thin film deposition under atmospheric pressure conditions led to increased interests for its application in optics, semiconductor production, automotive, or medical industry. Therefore, extensively research has been performed in the development of atmospheric pressure plasma sources for thin film deposition. Miniaturized non-thermal atmospheric pressure plasma jets represent a suitable tool for local surface coating and thus for the preparation of chemical micro-patterns. Consequently, investigations are of interest concerning the feasibility of plasma jets in surface engineering for customer-specific requirements. So far, two atmospheric pressure plasma jets with different geometries have been developed, which can be used for this purposes 1-2. In these set-ups, the supply of the precursor can be realized in different ways: I) the mixture of carrier gas and precursor is introduced into the main flow downstream the active discharge or II) by using a cap which was build to control and tailor the gas curtain which can diffuse into the effluent of the jet2-3. In the present paper, results are given of an experimental study on plasma enhanced chemical vapor deposition under atmospheric pressure conditions. Emphasis is given on depositing films which exhibit either hydrophilic (e.g. nitrogen-rich coatings) or hydrophobic surface properties (e.g. Teflon-like coatings). The chemical structure of these films, measured by X-ray photo electron spectroscopy, as well as their wettability will be shown and discussed. Deposition rates have been determined by weighing. Hence, by controlling the deposition conditions film growth rates of 6-43 nm s-1 have been obtained for fluorine-rich films, for example.