Cold Atmospheric Pressure Plasma VUV Interactions With Surfaces: Effect of Local Gas Environment and Source Design

Abstract

This study uses photoresist materials in combination with several optical filters as a diagnostic to examine the relative importance of VUV‐induced surface modifications for different cold atmospheric pressure plasma (CAPP) sources. The argon fed kHz‐driven ring‐APPJ showed the largest ratio of VUV surface modification relative to the total modification introduced, whereas the MHz APPJ showed the largest overall surface modification. The MHz APPJ shows increased total thickness reduction and reduced VUV effect as oxygen is added to the feed gas, a condition that is often used for practical applications. We examine the influence of noble gas flow from the APPJ on the local environment. The local environment has a decisive impact on polymer modification from VUV emission as O2 readily absorbs VUV photons.

Polymer etching by atmospheric‐pressure plasma jet and surface micro‐discharge sources: Activation energy analysis and etching directionality

“…While one could consider that there may be a contribution from the convection of the gas flow from the APPJ source since this gas flow is directional to some degree, based on gas flow kinetics for a laminar flow, this Ar flow stagnates approximately 1–2 mm above the top of the sample. This result was found as part of a finite element model of the APPJ gas flow which are described in previous work . This would suggest that the Ar gas flow should cease to contribute to the directionality of species once it reaches this point.…”

“…However, it is unlikely that the enhancement of the APPJ etching at closer distances is due to photons. While the MHz APPJ source has been shown to produce some VUV photons, the addition of oxygen to the feed gas typically quenches the photon effect seen at the surface . Additionally, the modification of photoresist by high energy photons leaves a very distinct densification of the polymer film which is not seen in the ellipsometry data for this etching.…”

“…The goal of this work is to understand two distinct CAP sources that behave very differently when interacting with thin polymer films and to understand key variables that determine outcomes at surfaces. Previous studies have shown that there are key differences between the plasma sources with regard to etching polymer films . We seek to compare a MHz APPJ source with a SMD source that between these two types have shown fundamentally different behavior with respect to their interactions with polymers surfaces.…”

Evolution of the Surface Wettability of PET Polymer upon Treatment with an Atmospheric-Pressure Plasma Jet

“…The radial dependence of VUV emission showed a ring shape with about 1 mm diameter and a minimum in the center. Moreover, Oehrlein et al [27] investigated the effect of VUV-induced surface modification using an optical window made from pure MgF 2 that transmits VUV down to the suitable wavelength. They investigated modification of polymethyl methacrylate (PMMA) based 193 nm photoresist (PR193) with 300 nm film thickness and polystyrene (PS) based 248 nm photoresist (PR248) with 400 nm film thickness.…”

Changes of 2H and 18O abundances in water treated with non‐thermal atmospheric pressure plasma jet

“…This is, mainly because of three reasons: (a) they are operated in open air; (b) they can be used to treat heat sensitive materials; and (c) there are many different non‐thermal, or “cold” atmospheric pressure plasma (CAPP) sources that provide a variety of different plasma geometries . CAPPs are sources of UV, VUV, IR and visible radiation, reactive oxygen and nitrogen species (ROS and RNS/RONS), electric fields, metastables, charged and neutral particles, etc . All these species interact in special manner with tissues in liquid environment.…”