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To validate the possibility of the developed microwave plasma source with a novel structure for plasma aerosol deposition, the characteristics of the plasma flow velocity generated from the microwave plasma source were investigated by a Mach probe with pressure variation. Simulation with the turbulent model was introduced to deduce calibration factor of the Mach probe and to compare experimental measurements for analyses of collisional plasma conditions. The results show calibration factor does not seem to be a constant parameter and highly dependent on the collision parameter. The measured plasma flow velocity, which witnessed fluctuations produced by a shock flow, was between 400 and 700 m/s. The optimized conditions for microwave plasma assisted aerosol deposition were derived by the results obtained from analyses of the parameters of microwave plasma jet. Under the optimized conditions, Y2O3 coatings deposited on an aluminum substrate were investigated using scanning electron microscope. The results presented in this study show the microwave plasma assisted aerosol deposition with the developed microwave plasma source is highly feasible for thick films with >50 μm.

To improve plasma and chemical resistance on various vacuum components used for semiconductor manufacturing equipment, various ceramic coating techniques have been applied. Among these methods for ceramic coating, the well-known atmospheric plasma spray (APS) is advantageous for providing thick film (100 µm or more) deposition. However, there are problems associated with the phase transition of the coating film and poor film quality due to formation of voids. To solve these problems, the aerosol deposition (AD) method has been developed. This method provides nice ceramic film quality. However, the coating rate is quite slow and has difficulty producing thick films (>30 µm). To overcome these limitations, microwave plasma-assisted aerosol deposition (μ-PAD) is applied at low vacuum conditions without the AD nozzle. This method uses a microwave plasma source during the AD process. After enduring a long-term durability test, as a trial run, μ-PAD has been applied on the actual process site. With the Al2O3 powder, μ-PAD shows a coating rate that is 12 times higher than the AD method. In addition, the formation of a thicker film (96 µm) deposition has been demonstrated. On the other hand, the coating film hardness, porosity, adhesion, and withstand voltage characteristics were confirmed to be less than the AD method.

To examine the possibility of using a gas molecule as an SF6 alternative gas, the insulation properties of the molecule must be estimated. In this work, we present a theoretical approach to calculate geometry parameters, electron scattering cross sections, and transport properties of nitrogen fluoride oxide (F3NO), which we have selected as an alternative to SF6. The molecular minimum structure of F3NO was optimized using the ɷB97X-D functional combined with the aug-cc-pVTZ basis set. Using this initial geometry obtained by the molecular structure calculation, the R-matrix calculation was done to obtain the elastic and momentum transfer cross section. The BE-f method was used for electronic excitation cross section. For the ionization cross section, the binary encounter Bethe method was used. From the calculated cross section data, the electron transport coefficients and reaction coefficients were calculated by solving the two-term approximated Boltzmann equation to investigate the discharge and insulation characteristics.

We carried out one-dimensional particle-in-cell and Monte Carlo collisional simulations of argon dc microplasmas. It is found that argon dc microplasmas have quite different electron kinetics from those of conventional low-pressure argon dc plasmas or helium dc microplasmas. The electron energy probability functions (EEPFs) of the argon dc microplasma are bi-Maxwellian for pressures exceeding 100 Torr, whereas it shows a convex-shaped profile for 10 Torr. The different EEPFs at high pressures come from the fact that, as the pressure is increased, elastic and inelastic electron–neutral collisions increase, because the cathode fall length decreases more slowly than the electron–neutral collisional mean free paths.