Remotely floating wire-assisted generation of high-density atmospheric pressure plasma and SF6-added plasma etching of quartz glass

• Published in: Journal of applied physics 2019-02, Vol.125 (6)
• Main Authors: Nguyen, Thi-Thuy-Nga, Sasaki, Minoru, Odaka, Hidefumi, Tsutsumi, Takayoshi, Ishikawa, Kenji, Hori, Masaru
• Format: Article
• Language: English
• Subjects: Applied physics; Atmospheric pressure; Coils; Electron density; Gas temperature; Glass plates; Plasma etching; Quartz; Silica glass; Tubes; Wire
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.5081875

High-density and large-volume atmospheric pressure plasma can be extended remotely by placing a long floating wire inside an Ar-gas flowing quartz tube connected with an inductively coupled coil. The discharge quartz tubes were categorized into three I-shaped tubes and one L-shaped tube. The influence of the geometrical design on plasma properties was investigated. Using the floating wire-assisted L tube, an electron density of 1014 cm−3 and a gas temperature less than 850 K were obtained at the downstream remote region. That is where the Ar plasma plume blew out from the slit at the bottom of the floating wire-assisted L tube at a distance of 140 mm from the coil center, when 100 W of a very high-frequency power (100 MHz) was applied to the inductively coupled coil. The applicability of this new L-type plasma source for large-area glass etching with a high etch rate was explored. At the remote region where the Ar plasma plume blew out of the slit of the L tube, SF6 gas was added for etching a quartz glass plate. Glass etching could be obtained over a large area of 15 mm × 20 mm with a maximum etch rate of 2 μm/min and a volume etch rate of 0.3 mm3/min.