With Extraction Electrode Patents (Class 315/111.31)
  • Patent number: 6956329
    Abstract: An apparatus for producing a stable, high pressure plasma column with long length, and high axial uniformity. Rotating a gas-filled tube about an horizontal axis creates a vortex with minimal, or no shear flow. Such a vortex provides a stable equilibrium for a central column of high temperature gas and plasma when, for a given rotation speed, the centrifugal force dominates over the gravitational force inside the smallest radial dimension of the containment envelope. For gas pressures sufficiently high that the particle mean free path is short compared with the thickness of the gas layer between the central plasma column and the wall, thermal transport across this sheath layer is small and its temperature is low. High pressure discharges inside a rotating envelope may be sustained by a variety of means, including electrical, electromagnetic and chemical; they may find application in plasma torches, light sources, etc.
    Type: Grant
    Filed: February 4, 2003
    Date of Patent: October 18, 2005
    Assignee: General Atomics
    Inventors: Neil H. Brooks, Torkil H. Jensen, Charles P. Moeller
  • Patent number: 6929712
    Abstract: A high-frequency current detector of a plasma processing apparatus detects a high-frequency current produced when high-frequency power in the range that does not cause generation of plasma in a chamber is supplied from a high-frequency power supply source to the chamber. The high-frequency current detector outputs the detected high-frequency current to a computer. The computer compares the high-frequency current received from the high-frequency current detector with a reference high-frequency current. When the received high-frequency current matches the reference high-frequency current, the computer determines that the process performance is normal. Otherwise, the computer determines that the process performance is abnormal. In this way, high-frequency characteristics specific to the apparatus are detected and the process performance are evaluated based on the detected high-frequency characteristics.
    Type: Grant
    Filed: September 6, 2002
    Date of Patent: August 16, 2005
    Assignee: Renesas Technology Corp.
    Inventors: Minoru Hanazaki, Keiichi Sugahara, Toshihiko Noguchi, Toshio Komemura, Masakazu Taki, Mutumi Tuda, Kenji Shintani
  • Patent number: 6909086
    Abstract: A neutral particle beam processing apparatus comprises a workpiece holder (20) for holding a workpiece (X), a plasma generator for generating a plasma in a vacuum chamber (3) by applying a high-frequency electric field, an orifice electrode (4) disposed between the workpiece holder (20) and the plasma generator, and a grid electrode (5) disposed upstream of the orifice electrode (4) in the vacuum chamber (3). The orifice electrode (4) has orifices (4a) defined therein. The neutral particle beam processing apparatus further comprises a voltage applying unit for applying a voltage between the orifice electrode (4) which serves as an anode and the grid electrode (5) which serves as a cathode, while the high-frequency electric field applied by the plasma generator is being interrupted, to accelerate negative ions in the plasma generated by the plasma generator and pass the accelerated negative ions through the orifices (4a) in the orifice electrode (4).
    Type: Grant
    Filed: March 22, 2002
    Date of Patent: June 21, 2005
    Assignees: Ebara Corporation, Japan as represented by President of Tohoku University
    Inventors: Seiji Samukawa, Katsunori Ichiki, Kazuo Yamauchi, Hirokuni Hiyama
  • Patent number: 6909087
    Abstract: A plasma generator generates positive ions and negative ions in a plasma. An ion extracting portion (4, 5) selectively extracts the generated positive ions and negative ions from the plasma, and accelerates the extracted ions in a predetermined direction. The positive ions and the negative ions are selectively applied to the workpiece (X). The plasma generator applies a high-frequency voltage to a process gas in a vacuum chamber for generating a plasma which is composed of positive ions and electrons from the process gas, and interrupts the high-frequency voltage for attaching the electrons to the residual process gas to generate negative ions. The application of the high-frequency voltage and the interruption of the high-frequency voltage are alternately repeated.
    Type: Grant
    Filed: March 22, 2002
    Date of Patent: June 21, 2005
    Assignee: Ebara Corporation
    Inventors: Katsunori Ichiki, Kazuo Yamauchi, Hirokuni Hiyama, Seiji Samukawa
  • Patent number: 6894298
    Abstract: The invention is directed to a method and an arrangement for generating extreme ultraviolet (EUV) radiation, i.e., radiation of high-energy photons in the wavelength range from 11 to 14 nm, based on a gas discharge. The object of the invention, to find a novel possibility for generating EUV radiation in which an extended life of the system is achieved with stable generation of a dense, hot plasma column, is met according to the invention in that a preionization discharge is ignited between two parallel disk-shaped flat electrodes prior to the main discharge by a surface discharge along the superficies surface of a cylindrical insulator with a plasma column generated through the gas discharge with pulsed direct voltage, which preionization discharge carries out an ionization of the working gas in the discharge chamber by means of fast charged particles.
    Type: Grant
    Filed: October 9, 2002
    Date of Patent: May 17, 2005
    Assignee: Xtreme technologies GmbH
    Inventors: Imtiaz Ahmad, Guido Schriever, Juergen Kleinschmidt
  • Patent number: 6885153
    Abstract: A method for determining the potential of a plasma in a processing chamber includes determining voltages of respective plasma engaging surfaces of at least two plasma generating electrodes disposed within the processing chamber and determining the plasma potential by comparing the determined voltages and equating the highest determined voltage to the plasma potential.
    Type: Grant
    Filed: November 26, 2003
    Date of Patent: April 26, 2005
    Assignee: Tokyo Electron Limited
    Inventor: Bill H Quon
  • Patent number: 6870321
    Abstract: A high-frequency electron source includes a discharge chamber having at least one gas inlet for a gas to be ionized and at least one extraction opening for electrons. The high-frequency electron source also includes a first electrode at least partially surrounding the discharge chamber and a keeper electrode at least partially surround the discharge chamber. The first electrode and the keeper electrode are configured to provide a high-frequency electric field therebetween.
    Type: Grant
    Filed: April 9, 2003
    Date of Patent: March 22, 2005
    Assignee: Astrium GmbH
    Inventors: Karl-Heinz Schartner, Horst Loeb, Hans Juergen Leiter, Hans-Peter Harmann
  • Patent number: 6861643
    Abstract: A neutral particle beam processing apparatus comprises a process gas inlet port (11) for introducing a process gas into a vacuum chamber (1), a plasma generating chamber (2) for generating positive ions and electrons from the introduced process gas, and a negative ion generating chamber (3) for attaching electrons generated in the plasma generating chamber to the residual gas to generate negative ions. The neutral particle beam processing apparatus further comprises an ion extracting portion (4) for extracting the positive ions or the negative ions and accelerating the positive ions or the negative ions in a predetermined direction, and a neutralizing chamber (5) for neutralizing an ion beam generated by the ion extracting portion (4) to generate a neutral particle beam. The neutral particle beam generated in the neutralizing chamber (5) is applied to a workpiece (X).
    Type: Grant
    Filed: March 22, 2002
    Date of Patent: March 1, 2005
    Assignee: Ebara Corporation
    Inventors: Katsunori Ichiki, Kazuo Yamauchi, Hirokuni Hiyama, Seiji Samukawa
  • Patent number: 6858838
    Abstract: A neutral particle beam processing apparatus comprises a plasma generator for generating positive ions and/or negative ions in a plasma, a pair of electrodes (5, 6) involving the plasma generated by the plasma generator therebetween, and a power supply (102) for applying a voltage between the pair of electrodes (5, 6). The pair of electrodes (5, 6) accelerate the positive ions and/or the negative ions generated by the plasma generator. The positive ions and/or the negative ions are neutralized and converted into neutral particles while being drifted in the plasma between the pair of electrodes (5, 6) toward a workpiece (X). The accelerated neutral particles pass through one of the electrodes (6) and are applied to the workpiece (X).
    Type: Grant
    Filed: March 22, 2002
    Date of Patent: February 22, 2005
    Assignee: Ebara Corporation
    Inventors: Katsunori Ichiki, Kazuo Yamauchi, Hirokuni Hiyama, Seiji Samukawa
  • Publication number: 20040212312
    Abstract: The present invention relates to a plasma source. The plasma source includes a cathode assembly. An anode is positioned adjacent to the cathode assembly. An excited atom source generates an initial plasma and excited atoms from a volume of feed gas. The initial plasma and excited atoms are located proximate to the cathode assembly. A power supply generates an electric field between the cathode assembly and the anode. The electric field super-ionizes the initial plasma so as to generate a high-density plasma.
    Type: Application
    Filed: May 12, 2003
    Publication date: October 28, 2004
    Applicant: ZOND, INC.
    Inventor: Roman Chistyakov
  • Patent number: 6759807
    Abstract: A multi-grid ion beam source has an extraction grid, an acceleration grid, a focus grid, and a shield grid to produce a highly collimated ion beam. A five grid ion beam source is also disclosed having two shield grids. The extraction grid has a high positive potential and covers a plasma chamber containing plasma. The acceleration grid has a non-positive potential. The focus grid is positioned between the acceleration grid and the shield grid. The combination of the extraction grid and the acceleration grid extracts ions from the plasma. The focus grid acts to change momentum of the ions exiting the acceleration grid, focusing the ions into a more collimated ion beam than previous approaches. In one embodiment, the focus grid has a large positive potential. In another embodiment, the focus grid has a large negative potential.
    Type: Grant
    Filed: April 4, 2002
    Date of Patent: July 6, 2004
    Assignee: Veeco Instruments, Inc.
    Inventor: Erik Karl Kristian Wåhlin
  • Patent number: 6717133
    Abstract: A method and apparatus for generating electrical fields within the ion flight path of a mass spectrometer are provided. Gratings having a planar array of parallel conductive strands and electrically connected to a voltage source are placed in the ion flight path so that at least a portion of the conductive strands traverses the flight path. The gratings may be arranged within the ion flight path so that the conductive strands of each of the gratings are aligned behind the conductive strands of a first grating, with respect to the ion flight path, thus providing high ion transmission.
    Type: Grant
    Filed: June 13, 2001
    Date of Patent: April 6, 2004
    Assignee: Agilent Technologies, Inc.
    Inventor: Gangqiang Li
  • Patent number: 6700329
    Abstract: Hollow cathode microdischarges in a tube geometry provides the formation of stable, high-pressure discharges in a variety of flowing gases including argon, helium, nitrogen, and hydrogen. Direct current discharges are ignited in stainless steel capillary tubes (dhole=178 &mgr;m) which are operated as the cathode and using a metal grid or plate as the anode. Argon discharges can be sustained at atmospheric pressure with voltages as low as 260 V for cathode-anode gaps of 0.5 mm. In one embodiment using a molybdenum substrate as the anode, microjets are struck in H2/CH4 mixtures at 200 Torr to deposit diamond films with well-faceted crystals. Optical emission spectroscopy of discharges used for growth confirms the presence of atomic hydrogen and CH radicals. Ballasting of individual tubes allows parallel operation of the microjets for larger area materials processing.
    Type: Grant
    Filed: April 3, 2002
    Date of Patent: March 2, 2004
    Assignee: California Institute of Technology
    Inventors: Konstantinos P. Giapis, Mohan Sankaran, Michael J. Gordon
  • Publication number: 20040032211
    Abstract: An rf ion source suitable for low power operation over a range of pressures in air which comprises discharge electrode, a cathode and an anode, the cathode being connected to an rf signal supply through an associated coupling means and the anode adapted to provide a surface area over which a plasma discharge may occur no greater than substantially that of the cathodal area over which the discharge may occur. The anode and cathode are arranged to be maneuverable with respect to one another in order to reduce the power requirements of the system and provide a means of controlling the rf discharge and ionization. An extended rf ion source, comprising a series of electrode pairs, provides flexibility for use in a variety of circumstances.
    Type: Application
    Filed: September 15, 2003
    Publication date: February 19, 2004
    Inventors: Marian Lesley Langford, Stuart Nevill Cairns, Andrew John Marr, Ian Blair Pleasants
  • Patent number: 6670623
    Abstract: A thermoregulation system for an ion implantation system to reduce the temperature in the ion implanter and components therein, or attached thereto, to a temperature at which an ion source material, used in the ion implanter, has a vapor pressure that yields a reduced concentration of vapors. Such arrangement markedly reduces the risk of exposure to harmful vapors from the ion source material.
    Type: Grant
    Filed: March 7, 2001
    Date of Patent: December 30, 2003
    Assignee: Advanced Technology Materials, Inc.
    Inventor: Michael C. Vella
  • Patent number: 6563907
    Abstract: Employing a source of radiation, such as an electric discharge source, that is equipped with a capillary region configured into some predetermined shape, such as an arc or slit, can significantly improve the amount of flux delivered to the lithographic wafers while maintaining high efficiency. The source is particularly suited for photolithography systems that employs a ringfield camera. The invention permits the condenser which delivers critical illumination to the reticle to be simplified from five or more reflective elements to a total of three or four reflective elements thereby increasing condenser efficiency. It maximizes the flux delivered and maintains a high coupling efficiency. This architecture couples EUV radiation from the discharge source into a ring field lithography camera.
    Type: Grant
    Filed: December 7, 2001
    Date of Patent: May 13, 2003
    Assignee: EUV LLC
    Inventors: Glenn D. Kubiak, William C. Sweatt
  • Publication number: 20030085663
    Abstract: An ion source for ion implantation system and a method of ion implantation employs a controlled broad, directional electron beam to ionize process gas or vapor, such as decaborane, within an ionization volume by primary electron impact, in CMOS manufacturing and the like. Isolation of the electron gun for producing the energetic electron beam and of the beam dump to which the energetic beam is directed, as well as use of the thermally conductive members for cooling the ionization chamber and the vaporizer, enable use with large molecular species such as decaborane, and other materials which are unstable with temperature. Electron optics systems, facilitate focusing of electrons from an emitting surface to effectively ionize a desired volume of the gas or vapor that is located adjacent the extraction aperture. The components enable retrofit into ion implanters that have used other types of ion sources.
    Type: Application
    Filed: September 16, 2002
    Publication date: May 8, 2003
    Inventor: Thomas N. Horsky
  • Patent number: 6554968
    Abstract: A method for producing film thickness control of ion beam sputter deposition films. Great improvements in film thickness control is accomplished by keeping the total current supplied to both the beam and suppressor grids of a radio frequency (RF) in beam source constant, rather than just the current supplied to the beam grid. By controlling both currents, using this method, deposition rates are more stable, and this allows the deposition of layers with extremely well controlled thicknesses to about 0.1%. The method is carried out by calculating deposition rates based on the total of the suppressor and beam currents and maintaining the total current constant by adjusting RF power which gives more consistent values.
    Type: Grant
    Filed: September 29, 2000
    Date of Patent: April 29, 2003
    Assignee: The Regents of the University of California
    Inventors: Patrick A. Kearney, Scott C. Burkhart
  • Patent number: 6545419
    Abstract: An improved double chamber ion source comprising a plasma generating chamber, a charge exchange chamber and a divider structure therebetween. The charge exchange chamber includes magnetic shielding material to reduce exposure of interior components to magnetic field lines externally generated. The double compartment ion source further comprises inclusion of a heat shield and/or a cooling system to overcome deleterious effects caused by increased temperature in the plasma generating chamber. The divider structure has a plurality of apertures having a configuration to reduce surface area on the divider structure in the charge exchange chamber.
    Type: Grant
    Filed: March 7, 2001
    Date of Patent: April 8, 2003
    Assignee: Advanced Technology Materials, Inc.
    Inventor: Michael C. Vella
  • Publication number: 20030057847
    Abstract: The present invention provides an apparatus and a method of generating and controlling plasma formed in a capacitively coupled plasma region between a plasma electrode and a bias electrode. The plasma electrode includes a plurality of sub-electrodes that are electrically insulated from one another. Radio frequency plasma generating electric power is provided to the plasma electrode. Radio frequency bias electric power, at a lower frequency than the plasma generating radio frequency electric power, is also provided. A first portion of the bias electric power is provided to the bias electrode, and a second portion of the bias electric power is provided to the plasma electrode. At least one filter, impedance matching network, phase shifter, and power splitter are used to affect the electric power provided to the electrodes.
    Type: Application
    Filed: August 27, 2002
    Publication date: March 27, 2003
    Inventor: Eric J. Strang
  • Patent number: 6528948
    Abstract: A plasma valve includes a confinement channel and primary anode and cathode disposed therein. An ignition cathode is disposed adjacent the primary cathode. Power supplies are joined to the cathodes and anode for rapidly igniting and maintaining a plasma in the channel for preventing leakage of atmospheric pressure through the channel.
    Type: Grant
    Filed: October 11, 2000
    Date of Patent: March 4, 2003
    Assignee: Brookhaven Science Associates LLC
    Inventors: Ady Hershcovitch, Sushil Sharma, John Noonan, Elbio Rotela, Ali Khounsary
  • Publication number: 20020134508
    Abstract: There are provided a matching unit capable of sufficiently matching the impedance of a high frequency load to a transmission path impedance without increasing its size and matching time even if a high frequency power of 70 MHz or higher is supplied thereto, and a plasma processing system using the same.
    Type: Application
    Filed: April 12, 2002
    Publication date: September 26, 2002
    Inventors: Shinji Himori, Mitsuhiro Yuasa, Kazuyoshi Watanabe, Jun?apos;ichi Shimada
  • Patent number: 6417625
    Abstract: An apparatus for producing a stable, high pressure plasma column with long length, and high axial uniformity. Rotating a gas-filled tube about an horizontal axis creates a vortex with minimal, or no shear flow. Such a vortex provides a stable equilibrium for a central column of high temperature gas and plasma when, for a given rotation speed, the centrifugal force dominates over the gravitational force inside the smallest radial dimension of the containment envelope. High pressure discharges inside a rotating envelope may be sustained by a variety of energy sources, including electrical, electromagnetic and chemical; they may find application in plasma torches, light sources, etc.
    Type: Grant
    Filed: August 4, 2000
    Date of Patent: July 9, 2002
    Assignee: General Atomics
    Inventors: Neil H. Brooks, Torkil H. Jensen, Charles P. Moeller
  • Patent number: 6414438
    Abstract: A method and apparatus produce short-wave radiation from a gas-discharge plasma, comprising pre-ionization of the gas in the discharge region between coaxial electrodes achieved through an axial aperture formed in one of the electrodes and initiation of a pinch-type discharge. In order to increase the efficiency, energy, average power and stability of the radiation of the gas-discharge plasma, pre-ionization is achieved by a flux of radiation having wavelengths from the UV to X-ray range and by a flux of accelerated electrons from the plasma of a pulsed sliding discharge initiated in a region not optically communicating with the axis of the pinch-type discharge, with a rate of growth of the discharge voltage across the region of more than 1011 V/s, the fluxes of radiation and electrons being formed axially symmetrically and directed into the part of the discharge region outside the axis.
    Type: Grant
    Filed: October 20, 2000
    Date of Patent: July 2, 2002
    Assignee: Lambda Physik AG
    Inventors: Vladimir Mikhailovich Borisov, Oleg Borisovich Khristoforov
  • Patent number: 6388381
    Abstract: A miniaturized construction and slit end orifice configurations of a constricted glow discharge chamber and method are disclosed. The polarity and geometry of the constricted glow discharge plasma source is set so that the contamination and energy of the ions discharged from the source are minimized. The several sources can be mounted in parallel and in series to provide a sustained ultra low source of ions in a homogeneous linear plasma stream with contamination below practical detection limits. Other configuration include a hollow chamber with an anode outside the chamber located opposite its discharge constriction orifice. The constriction orifice may be circular or a slit and can be aligned to form a linear array for processing web substrates.
    Type: Grant
    Filed: February 19, 1999
    Date of Patent: May 14, 2002
    Assignee: The Regents of the University of California
    Inventor: Andre Anders
  • Publication number: 20020008480
    Abstract: A plasma treatment apparatus having the capability of uniformly treating an object with plasma at a high treatment speed and a plasma treatment method are provided. This apparatus comprises a tubular vessel having a laterally elongated cross section, a pair of electrodes arranged such that electric flux lines develop substantially in an axial direction of the tubular vessel when one of an AC voltage and a pulse voltage is applied between the electrodes, a gas supply for supplying a streamer generation gas into the tubular vessel, a power source for applying the voltage between the electrodes to generate plural streamers of the gas in the tubular vessel, and a plasma uniform means for making the plural streamers uniform in a lateral direction of the laterally elongated cross section of the tubular vessel to provide the plasma from one end of the tubular vessel.
    Type: Application
    Filed: May 24, 2001
    Publication date: January 24, 2002
    Applicant: Matsushita Electric Works, Ltd.
    Inventors: Keiichi Yamazaki, Yukiko Inooka, Yasushi Sawada, Noriyuki Taguchi, Yoshiyuki Nakazono, Akio Nakano
  • Publication number: 20020000779
    Abstract: A miniaturized construction and slit end orifice configurations of a constricted glow discharge chamber and method are disclosed. The polarity and geometry of the constricted glow discharge plasma source is set so that the contamination and energy of the ions discharged from the source are minimized. The several sources can be mounted in parallel and in series to provide a sustained ultra low source of ions in a homogeneous linear plasma stream with contamination below practical detection limits. Other configuration include a hollow chamber with an anode outside the chamber located opposite its discharge constriction orifice. The constriction orifice may be circular or a slit and can be aligned to form a linear array for processing web substrates.
    Type: Application
    Filed: February 19, 1999
    Publication date: January 3, 2002
    Inventor: ANDRE ANDERS
  • Patent number: 6320321
    Abstract: In order to uniformly neutralize a large current and a large diameter ion beam so as to irradiate an ion beam having a reduced beam divergence on a process target, an ion beam processing apparatus comprises an ion source for producing a processing plasma, a processing chamber as a vacuum chamber for accommodating a process target, an extract electrode for extracting an ion beam so as to irradiate on said process target, an annular electrode disposed in said processing chamber for forming an annular magnetic field therein, through which said ion beam is irradiated on said process, and a wave guide for introducing microwave through an opening provided on a wall forming said processing chamber, into said annular magnetic field.
    Type: Grant
    Filed: January 2, 2001
    Date of Patent: November 20, 2001
    Assignee: Hitachi, Ltd.
    Inventors: Satoshi Ogura, Shotaro Ooishi, Isao Hashimoto, Satoshi Ichimura
  • Patent number: 6300720
    Abstract: A high pulse repetition frequency (PRF) plasma gun is provided, which gun inlets a selected propellant gas into a column formed between a center electrode and a coaxial outer electrode, utilizes a solid state high repetition rate pulse driver to provide a voltage across the electrodes and provides a plasma initiator at the base of the column, which is normally operative when the driver is fully charged. For preferred embodiments, the initiator includes a sold state simulated RF driver, the outputs from which are applied to electrodes affixed in an insulator and producing a high voltage field at a surface of the insulator which forms part of the base end of the column. The plasma expands from the base end of the column and off the exit end thereof.
    Type: Grant
    Filed: March 31, 1999
    Date of Patent: October 9, 2001
    Inventor: Daniel Birx
  • Patent number: 6278241
    Abstract: A four-nozzle plasma generator comprising two anode electrode chambers and two cathode electrode chambers connected to DC power sources and generating four plasma jets of which the shape and the path are determined by an external magnetic field system. The plasma jets converge on a central area into which the material to be processed is injected, in order to form a single plasma stream. The nozzles are symmetrically arranged on a hood which includes a flat water-cooled diaphragm provided with a central aperture.
    Type: Grant
    Filed: November 23, 1998
    Date of Patent: August 21, 2001
    Assignee: TePla AG
    Inventors: Vladimir Enguelcht, Pavel Koulik, Evgenia Zorina, Stanislav Begounov, Rudolph Konavko, Anatolii Saitschenko, Mikhail Samsonov, Ioulia Tsvetkova
  • Patent number: 6172324
    Abstract: This invention relates to a plasma focus source for generating radiation at a selected wavelength, the invention involving producing a high energy plasma sheathe which moves down an electrode column at high speed and is pinched at the end of the column to form a very high temperature spot. An ionizable gas introduced at the pinch can produce radiation at the desired wavelength. In order to prevent separation of the plasma sheathe from the pinch, and therefore to prolong the pinch and prevent potentially damaging restrike, a shield of a high temperature nonconducting material is positioned a selected distance from the center electrode and shaped to redirect the plasma sheathe to the center electrode, preventing separation thereof. An opening is provided in the shield to permit the desired radiation to pass substantially unimpeded.
    Type: Grant
    Filed: July 13, 1999
    Date of Patent: January 9, 2001
    Assignee: Science Research Laboratory, Inc.
    Inventor: Daniel Birx
  • Patent number: 6169370
    Abstract: A device for producing RF/HF induced low-energy plasma, in particular noble gas plasma, including a generator and a supply element for the plasma gas. The generator is coupled in a known manner to two, in particular, ring- or disk-shaped parallel, interspaced electrodes, each having at least one through-opening, and for at least one isolator to be positioned between the electrodes, the isolator having at least one particularly circular through-opening assigned to the through-opening of the electrode, whose through-opening is designed to confine the plasma formed by a plasma gas at a pressure of at least 0.01 bars, but preferably between 0.1 and 5 bars. The inside diameter of the through-opening of the electrodes is at least double, but especially approximately four to eight times that of the inside diameter of the through-opening of the isolator for confining the plasma.
    Type: Grant
    Filed: September 3, 1999
    Date of Patent: January 2, 2001
    Inventor: Bernhard Platzer