Nonhomogeneous surface properties of parylene-C film etched by an atmospheric pressure He/O-2 micro-plasma jet in ambient air

摘要

Surface properties of parylene-C film etched by an atmospheric pressure He/O-2 micro-plasma jet in ambient air were investigated. The morphologies and chemical compositions of the etched surface were analyzed by optical microscopy, SEM, EDS, XPS and ATR-FTIR. The microscopy and SEM images showed the etched surface was nonhomogeneous with six discernable ring patterns from the center to the outside domain, which were composed of (I) a central region; (II) an effective etching region, where almost all of the parylene-C film was removed by the plasma jet with only a little residual parylene-C being functionalized with carboxyl groups (C=O, O-C=O-); (III) an inner etching boundary; (IV) a middle etching region, where the film surface was smooth and partially removed; (V) an outer etching boundary, where the surface was decorated with clusters of debris, and (VI) a pristine parylene-C film region. The analysis of the different morphologies and chemical compositions illustrated the different localized etching process in the distinct regions. Besides, the influence of O-2 flow rate on the surface properties of the etched parylene-C film was also investigated. Higher volume of O-2 tended to weaken the nonhomogeneous characteristics of the etched surface and improve the etched surface quality. (C) 2016 Elsevier B.V. All rights reserved.