Production of high-density capacitively coupled radio-frequency discharge plasma by high-secondary-electron-emission oxide

Ohtsu, Yasunori; Fujita, Hiroharu

doi:10.1063/1.1827353

Cited by 23 publications

(17 citation statements)

References 10 publications

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“…Additionally, the etching was performed at relatively lower chamber pressure (6.66 Pa) compared to the conventional plasma etching (13–66 Pa) . Under low chamber pressure ( P c ) the ohmic heating can be neglected and the dependence of plasma density ( n p ) on the frequency ( f ) of the rf generator can be expressed by Equation

n_{normalp} \propto \frac{{(2 π f)}^{2} V_{r f}}{ξ}

where V rf being the rf voltage applied between the electrodes and ξ being the energy needed to generate electrons and ions.…”

Section: Discussionmentioning

confidence: 99%

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Study of the VHF Plasma Etching of Micro/Nano Patterned PMMA Coated on Ultra‐Thin Flexible Glass Substrates

Mandal

Kole

Garner

et al. 2016

Plasma Processes & Polymers

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Flexible substrates are useful for roll to roll production of photovoltaic modules. In this study, we have demonstrated DVD (digital versatile disc) like pattern replication from a Nickel mold onto PMMA coated ultra‐thin flexible Corning® Willow® Glass substrates (thickness 150 μm) by thermal nanoimprint lithography (T‐NIL) technique. These embossed PMMA coatings were subsequently etched in a capacitively coupled very high frequency (VHF) discharge of 40.68 MHz using Ar/O2 gas mixture at a chamber pressure of 6.66 Pa for different periods of etching times in the range from 6 to 600 s. High plasma density under VHF together with low gas pressure promote ion directionality toward the substrate. Identification of the emitted species during the etching process was carried out by a quadrupole mass spectrometer. The temporal evolution of the etched patterns on PMMA was studied in detail by atomic force microscopy. The study may be helpful for understanding the plasma etching process of the micro/nano patterned PMMA under VHF leading to the surface structuring on the ultra‐thin flexible glass substrates.

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n_{normalp} \propto \frac{{(2 π f)}^{2} V_{r f}}{ξ}

where V rf being the rf voltage applied between the electrodes and ξ being the energy needed to generate electrons and ions.…”

Section: Discussionmentioning

confidence: 99%

“…[19] Under low chamber pressure (P c ) the ohmic heating can be neglected and the dependence of plasma density (n p ) on the frequency (f) of the rf generator can be expressed by Equation 1. [20,21]…”

Section: Discussionmentioning

confidence: 99%

Study of the VHF Plasma Etching of Micro/Nano Patterned PMMA Coated on Ultra‐Thin Flexible Glass Substrates

Mandal

Kole

Garner

et al. 2016

Plasma Processes & Polymers

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“…The electron temperature and density as well as the plasma potential are obtained radially resolved from measurements of the current-voltage characteristics of a tiny cylindrical tungsten probe according to Langmuir probe theory 7,52,53 at various trench depths. The probe system is compensated with an L-C parallel circuit 12,26,[30][31][32][33][42][43][44] (choke) in order to avoid any parasitic effects of rf plasma potential oscillations on the probe current-voltage characteristics. At the gas pressure of 53.2 Pa, the electron-neutral mean free path is smaller than the dimensions of the probe and the electron saturation current detected by the probe must be revised.…”

Section: Methodsmentioning

confidence: 99%

“…Some solutions have been proposed as follows: (1) Very high frequencies (VHF) are used to increase the plasma density at a given input power, since the plasma density typically scales with the square of the driving frequency. 7,[26][27][28] (2) Electrodes made of materials with high-secondary electron emission coefficients 12,[29][30][31][32] are used, because the secondary electrons participate in ionization and, thus, enhance the plasma density. 33,34 (3) The processing gas mixture is optimized to maximize the ionization probability.…”

Section: Introductionmentioning

confidence: 99%

Capacitive radio frequency discharges with a single ring-shaped narrow trench of various depths to enhance the plasma density and lateral uniformity

et al. 2016

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Spatial structures of the electron density and temperature in ring-shaped hollow cathode capacitive rf plasma with a single narrow trench of 2 mm width have been investigated at various trench depths of D ¼ 5, 8, 10, 12, and 15 mm. It is found that the plasma density is increased in the presence of the trench and that the radial profile of the plasma density has a peak around the narrow hollow trench near the cathode. The density becomes uniform further away from the cathode at all trench depths, whereas the electron temperature distribution remains almost uniform. The measured radial profiles of the plasma density are in good agreement with a theoretical diffusion model for all the trench depths, which explains the local density increase by a local enhancement of the electron heating. Under the conditions investigated, the trench of 10 mm depth is found to result in the highest plasma density at various axial and radial positions. The results show that the radial uniformity of the plasma density at various axial positions can be improved by using structured electrodes of distinct depths rather than planar electrodes. V

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“…In general, plasma is generated by electrons with an energy higher than an ionization potential of target neutral gas [19]. According to the ionization cross section [20] for noble gases of He, Ne, Ar, and Xe, their ionization energy ranges from 10 to 30 eV, while the energy is a few 100 electron volts when the ionization cross section becomes maximum.…”

Section: Effect Of High Secondary Electron Emission Oxide On High-denmentioning

confidence: 99%

Physics of High-Density Radio Frequency Capacitively Coupled Plasma with Various Electrodes and Its Applications

Ohtsu¹

2019

Plasma Science and Technology - Basic Fundamentals and Modern Applications

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The radio frequency discharge plasma sources are widely utilized to prepare functional thin films and to etch insulated layers in semiconductor devices in microelectronic industry. Especially, a capacitively coupled plasma (CCP) is the most popular discharge because the equipment is very simple and almost maintenance free. However, there is a problem such as low-density plasma under low-gas pressure less than 10 Pa, that is, low processing rate. In this chapter, the production principle of conventional CCP and the special CCP with various electrodes and magnets is reviewed. The applications prepared by the special CCP system are also presented. Finally, the future plan including problems is described.

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Production of high-density capacitively coupled radio-frequency discharge plasma by high-secondary-electron-emission oxide

Cited by 23 publications

References 10 publications

Study of the VHF Plasma Etching of Micro/Nano Patterned PMMA Coated on Ultra‐Thin Flexible Glass Substrates

Study of the VHF Plasma Etching of Micro/Nano Patterned PMMA Coated on Ultra‐Thin Flexible Glass Substrates

Capacitive radio frequency discharges with a single ring-shaped narrow trench of various depths to enhance the plasma density and lateral uniformity

Physics of High-Density Radio Frequency Capacitively Coupled Plasma with Various Electrodes and Its Applications

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