Diagnostics of N₂–Ar plasma mixture excited in a 13.56 MHz hollow cathode discharge system: application to remote plasma treatment of polyamide surface

Abstract

N2–x% Ar plasma gas mixture, generated in a hollow cathode RF discharge system, has been characterized by both optical emission spectroscopy (OES) and double Langmuir probe, as a function of experimental parameters: total pressure (5–33 Pa), and different fractions of argon (7 ≤ x ≤ 80), at a constant applied RF power of 300 W. N2 dissociation degree has been investigated qualitatively by both the actinometry method and the ratio of the atomic nitrogen line emission intensity at 672.3 nm to the vibrational band (0–0) of the N2 second positive system at 337.1 nm. Both methods showed that the increase in argon fraction enhances the dissociation of N2, with a maximum at x = 50 for the pressure of 5 Pa, although the two methods give two opposite trends as a function of total pressure. Spectroscopic measurements showed that the vibrational temperature of the N2 second positive system increases with both argon fraction and total pressure increase, it lies between 4900 and 12 300 K. Langmuir probe measurements showed that, in the remote zone, the electron temperature falls in the range 1.57–1.75 eV, the density varies between 5 × 109 and 1.4 × 1010 cm−3 and that both the plasma ionization degree and electron temperature increase towards the source. In addition, the process of plasma–polyamide (PA) surface interaction, in the remote plasma zone, has been studied through OES analysis during plasma treatment of PA to monitor the possible emissions due to the polymer etching. An increase in atomic nitrogen line (672.3 nm) intensity is obtained, atomic carbon line (833.52 nm) and the band emission (0–0) from the CN (B 2Σ+–X 2Σ+) violet system were observed. The PA surface modification has been confirmed through the improvement of its hydrophilic character as the water contact angle measured after the plasma treatment significantly decreased.

Silicon Nanostructuring Using SF6/O2 Downstram Plasma Etching: Morphological, Optical and Sensing Properties

“…4 This passivation layer is not very stable and dissociates by heating or under the ion bombardment of the plasma. 9,10 Since our system is a remote plasma configuration, where the concentrations of ions and electrons are relatively low and the concentration of free radicals is relatively high in the remote region far from the primary plasma, 17 the behavior of the etching rate as a function of O 2 content in the SF 6 /O 2 plasma, may be related to the fact that the passivation layer resists the degradation by plasma ions bombardment in the downstream etching region. Thus, this layer plays a significant role in the etching rate lowering beyond 5% O 2 content.…”

Wall loss of atomic nitrogen determined by ionization threshold mass spectrometry

“…A more detailed discussion of the conditions of this method can be found in Biloiu et al 26 . In the present work the electronic transition of J" of the rotational bands of the considered transition is a function of the following variables 23,25,27 :…”

Surface modification of a polyamide 6 film by He/CF4 plasma using atmospheric pressure plasma jet

“…The peak areas of C-O/C-CF 2 and CONH/CF all increased whereas that of C-C/C-N decreased after the plasma treatment. Obviously this was resulted from fluorination and disassociation of the amide groups originally in PA 6 [29]. The deconvolution analysis of F1s is shown in Fig.…”

“…Saloum et al [29] have analyzed the composition of plasmas when treating PA 6 films with low pressure N 2 -Ar plasma and found that N and N + increase significantly as a result of disassociation of the amide groups on the polymer surface when the plasma interacted with PA 6 surface. Yip et al [30] have reported that when PA 6 fibers are treated with low pressure O 2 plasma, sub-micron ripples perpendicular to the fiber axis are formed on the fiber surfaces as a result of plasma etching due to existence of a stress field.…”