Production of large-diameter plasma using multi-slotted planar antenna

Abstract

It is reported that a large-diameter uniform plasma is obtained by microwave discharges using multi-slotted planar (MSP) antenna. The MSP antenna radiates the microwave field from a large number of slots so as to form a uniform radial distribution of the field in the outer radii. Overdense plasmas are produced with ±3-4% uniformity of the ion saturation current over a 30 cm diameter for Ar pressures of 5-10 mTorr and microwave powers of 1-3 kW. The efficient production of overdense plasmas may be due to the enhancement of the microwave field of oblique incidence at the plasma resonance.

Effect of wave-mode conversion device on production of large-area rectangular overdense surface-wave plasmas at the gas pressure about 100 Pa

“…Therefore, the development and application researches of the large-scale overdense SWP have attracted the unprecedented attention and the current study focus on the spatial uniformity and the temporal stability in large area. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] To address the above concerns, a lot of planar-type SWP sources have been optimized. As for these sources, the uniformity of plasma below the dielectric slab is one of the most important factors.…”

“…Therefore, a possible way to control the discharge effectively is to utilize the plasmadielectric resonator, i.e., to apply the periodic slot antennas as the microwave energy excitation. [7][8][9][10][11][12][13][14] However, the SWP sources designed with the special wave-mode conversion device are not clearly described at the discharge pressure of about 100 Pa. Furthermore, the effect of wave-mode conversion device on the production of large-area uniform stable overdense plasmas has not been proposed.…”

High-power microwave discharge for producing large-area surface-wave plasmas

“…Therefore, SWP have been exhaustively investigated both theoretically and experimentally [1][2][3][4][5][6]. For example, M. Nagatsu et al [2] have yielded large-area surface-wave plasmas with an internally mounted planar cylindrical launcher, Y. Yasaka et al [7][8][9] have produced large-diameter uniformity plasma using multislotted planar antenna, and C. Tian et al [10] have studied characteristics of large-diameter plasma using a radial-line slot antenna. But most of the structure of chamber reported in the literature is circular cylinder; a rectangular cavity [11][12][13] is adopted in this article.…”

Experiment and modeling of plasma and neutral transports in slot-excited microwave discharges

“…Furthermore, the radiated field is rotating in the azimuthal direction smoothing out azimuthal nonuniformity, if any. Using this multi-slotted planar (MSP) antenna device, we have obtained overdense argon plasmas with uniformities better than 3% for 30-cm diameter [1]. In order to apply this MSP device to material processing, we investigate transports of plasma and neutral particles associated with convection, diffusion, and chemical reactions.…”