抄録
An atmospheric-pressure argon (Ar) plasma jet was generated with a frequency of 10 kHz, an applied voltage of 10 kV, and an Ar gas flow rate of 10 L/min. When an aluminum (Al) thin film deposited on a glass substrate was irradiated with the Ar plasma jet in air for 5 s, Al was removed. The removal rate was ∼700 nm/s. Because the streamers in the plasma reached the Al thin film, Al was removed and a mark was formed on the film, which was referred to as a removal mark. The shape of the removal mark depended on the irradiation distance: it was ring-shaped with an inner diameter of ∼5 mm and an outer diameter of ∼6 mm for irradiation distances of 2–7 mm, and disc-shaped with a diameter of ∼5 mm for irradiation distances of 10–20 mm. The dependence of the shape of the removal mark on the irradiation distance suggests that the distribution of the streamers in the plasma depended on the irradiation distance. The streamers inside the quartz tube were concentrated along the inner wall. In contrast, the streamers outside the tube were distributed in a ring shape with an inner diameter of ∼5 mm and an outer diameter of ∼6 mm for irradiation distances of 2–7 mm, but they converged then diverged to form a smaller disc shape with a diameter of ∼5 mm for irradiation distances of 10–20 mm. [DOI: 10.1380/ejssnt.2016.231]
