Patents by Inventor Ka-Ngo Leung

Ka-Ngo Leung has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7084407
    Abstract: An extractor system for a plasma ion source has a single (first) electrode with one or more apertures, or a pair of spaced electrodes, a first or plasma forming electrode and a second or extraction electrode, with one or more aligned apertures. The aperture(s) in the first electrode (or the second electrode or both) have a counterbore on the downstream side (i.e. away from the plasma ion source or facing the second electrode). The counterbored extraction system reduces aberrations and improves focusing. The invention also includes an ion source with the counterbored extraction system, and a method of improving focusing in an extraction system by providing a counterbore.
    Type: Grant
    Filed: February 13, 2003
    Date of Patent: August 1, 2006
    Assignee: The Regents of the University of California
    Inventors: Qing Ji, Keith Standiford, Tsu-Jae King, Ka-Ngo Leung
  • Patent number: 6985553
    Abstract: An ion source has an extraction system configured to produce ultra-short ion pulses, i.e. pulses with pulse width of about 1 ?s or less, and a neutron source based on the ion source produces correspondingly ultra-short neutron pulses. To form a neutron source, a neutron generating target is positioned to receive an accelerated extracted ion beam from the ion source. To produce the ultra-short ion or neutron pulses, the apertures in the extraction system of the ion source are suitably sized to prevent ion leakage, the electrodes are suitably spaced, and the extraction voltage is controlled. The ion beam current leaving the source is regulated by applying ultra-short voltage pulses of a suitable voltage on the extraction electrode.
    Type: Grant
    Filed: January 23, 2003
    Date of Patent: January 10, 2006
    Assignee: The Regents of the University of California
    Inventors: Ka-Ngo Leung, William A. Barletta, Joe W. Kwan
  • Patent number: 6975072
    Abstract: A radio frequency (RF) driven plasma ion source has an external RF antenna, i.e. the RF antenna is positioned outside the plasma generating chamber rather than inside. The RF antenna is typically formed of a small diameter metal tube coated with an insulator. An external RF antenna assembly is used to mount the external RF antenna to the ion source. The RF antenna tubing is wound around the external RF antenna assembly to form a coil. The external RF antenna assembly is formed of a material, e.g. quartz, which is essentially transparent to the RF waves. The external RF antenna assembly is attached to and forms a part of the plasma source chamber so that the RF waves emitted by the RF antenna enter into the inside of the plasma chamber and ionize a gas contained therein. The plasma ion source is typically a multi-cusp ion source.
    Type: Grant
    Filed: May 22, 2003
    Date of Patent: December 13, 2005
    Assignee: The Regents of the University of California
    Inventors: Ka-Ngo Leung, Qing Ji, Stephen Wilde
  • Patent number: 6974950
    Abstract: The positive and negative ion beam merging system extracts positive and negative ions of the same species and of the same energy from two separate ion sources. The positive and negative ions from both sources pass through a bending magnetic field region between the pole faces of an electromagnet. Since the positive and negative ions come from mirror image positions on opposite sides of a beam axis, and the positive and negative ions are identical, the trajectories will be symmetrical and the positive and negative ion beams will merge into a single neutral beam as they leave the pole face of the electromagnet. The ion sources are preferably multicusp plasma ion sources. The ion sources may include a multi-aperture extraction system for increasing ion current from the sources.
    Type: Grant
    Filed: August 30, 2002
    Date of Patent: December 13, 2005
    Assignee: The Regents of the University of California
    Inventors: Ka-Ngo Leung, Jani Reijonen
  • Publication number: 20050220244
    Abstract: A cylindrical neutron generator is formed with a coaxial RF-driven plasma ion source and target. A deuterium (or deuterium and tritium) plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical neutron generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which contain many slots. The plasma generator emanates ions radially over 360° and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired. The plasma generator may be in the center and the neutron target on the outside, or the plasma generator may be on the outside and the target on the inside. In a nested configuration, several concentric targets and plasma generating regions are nested to increase the neutron flux.
    Type: Application
    Filed: April 19, 2005
    Publication date: October 6, 2005
    Inventor: Ka-Ngo Leung
  • Patent number: 6924493
    Abstract: A maskless plasma-formed ion beam lithography tool provides for patterning of sub-50 nm features on large area flat or curved substrate surfaces. The system is very compact and does not require an accelerator column and electrostatic beam scanning components. The patterns are formed by switching beamlets on or off from a two electrode blanking system with the substrate being scanned mechanically in one dimension. This arrangement can provide a maskless nano-beam lithography tool for economic and high throughput processing.
    Type: Grant
    Filed: August 17, 2000
    Date of Patent: August 2, 2005
    Assignee: The Regents of the University of California
    Inventor: Ka-Ngo Leung
  • Patent number: 6922019
    Abstract: A compact microwave ion source has a permanent magnet dipole field, a microwave launcher, and an extractor parallel to the source axis. The dipole field is in the form of a ring. The microwaves are launched from the middle of the dipole ring using a coaxial waveguide. Electrons are heated using ECR in the magnetic field. The ions are extracted from the side of the source from the middle of the dipole perpendicular to the source axis. The plasma density can be increased by boosting the microwave ion source by the addition of an RF antenna. Higher charge states can be achieved by increasing the microwave frequency. A xenon source with a magnetic pinch can be used to produce intense EUV radiation.
    Type: Grant
    Filed: May 17, 2002
    Date of Patent: July 26, 2005
    Assignee: The Regents of the University of California
    Inventors: Ka-Ngo Leung, Jani Reijonen, Rainer W. Thomae
  • Patent number: 6907097
    Abstract: A cylindrical neutron generator is formed with a coaxial RF-driven plasma ion source and target. A deuterium (or deuterium and tritium) plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical neutron generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which contain many slots. The plasma generator emanates ions radially over 360° and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired. The plasma generator may be in the center and the neutron target on the outside, or the plasma generator may be on the outside and the target on the inside. In a nested configuration, several concentric targets and plasma generating regions are nested to increase the neutron flux.
    Type: Grant
    Filed: March 18, 2002
    Date of Patent: June 14, 2005
    Assignee: The Regents of the University of California
    Inventor: Ka-Ngo Leung
  • Patent number: 6888146
    Abstract: A maskless micro-ion-beam reduction lithography system is a system for projecting patterns onto a resist layer on a wafer with feature size down to below 100 nm. The MMRL system operates without a stencil mask. The patterns are generated by switching beamlets on and off from a two electrode blanking system or pattern generator. The pattern generator controllably extracts the beamlet pattern from an ion source and is followed by a beam reduction and acceleration column.
    Type: Grant
    Filed: April 9, 1999
    Date of Patent: May 3, 2005
    Assignee: The Regents of the University of California
    Inventors: Ka-Ngo Leung, William A. Barletta, David O. Patterson, Richard A. Gough
  • Patent number: 6870894
    Abstract: A compact neutron generator has at its outer circumference a toroidal shaped plasma chamber in which a tritium (or other) plasma is generated. A RF antenna is wrapped around the plasma chamber. A plurality of tritium ion beamlets are extracted through spaced extraction apertures of a plasma electrode on the inner surface of the toroidal plasma chamber and directed inwardly toward the center of neutron generator. The beamlets pass through spaced acceleration and focusing electrodes to a neutron generating target at the center of neutron generator. The target is typically made of titanium tubing. Water is flowed through the tubing for cooling. The beam can be pulsed rapidly to achieve ultrashort neutron bursts. The target may be moved rapidly up and down so that the average power deposited on the surface of the target may be kept at a reasonable level. The neutron generator can produce fast neutrons from a T-T reaction which can be used for luggage and cargo interrogation applications.
    Type: Grant
    Filed: April 8, 2003
    Date of Patent: March 22, 2005
    Assignee: The Regents of the University of California
    Inventors: Ka-Ngo Leung, Tak Pui Lou
  • Publication number: 20040146133
    Abstract: An ion source has an extraction system configured to produce ultra-short ion pulses, i.e. pulses with pulse width of about 1 &mgr;s or less, and a neutron source based on the ion source produces correspondingly ultra-short neutron pulses. To form a neutron source, a neutron generating target is positioned to receive an accelerated extracted ion beam from the ion source. To produce the ultra-short ion or neutron pulses, the apertures in the extraction system of the ion source are suitably sized to prevent ion leakage, the electrodes are suitably spaced, and the extraction voltage is controlled. The ion beam current leaving the source is regulated by applying ultra-short voltage pulses of a suitable voltage on the extraction electrode.
    Type: Application
    Filed: January 24, 2003
    Publication date: July 29, 2004
    Inventors: Ka-Ngo Leung, William A. Barletta, Joe W. Kwan
  • Patent number: 6768120
    Abstract: An electron beam system is based on a plasma generator in a plasma ion source with an accelerator column. The electrons are extracted from a plasma cathode in a plasma ion source, e.g. a multicusp plasma ion source. The beam can be scanned in both the x and y directions, and the system can be operated with multiple beamlets. A compact focused ion or electron beam system has a plasma ion source and an all-electrostatic beam acceleration and focusing column. The ion source is a small chamber with the plasma produced by radio-frequency (RF) induction discharge. The RF antenna is wound outside the chamber and connected to an RF supply. Ions or electrons can be extracted from the source. A multi-beam system has several sources of different species and an electron beam source.
    Type: Grant
    Filed: August 30, 2002
    Date of Patent: July 27, 2004
    Assignee: The Regents of the University of California
    Inventors: Ka-Ngo Leung, Jani Reijonen, Arun Persaud, Qing Ji, Ximan Jiang
  • Publication number: 20040104683
    Abstract: A radio frequency (RF) driven plasma ion source has an external RF antenna, i.e. the RF antenna is positioned outside the plasma generating chamber rather than inside. The RF antenna is typically formed of a small diameter metal tube coated with an insulator. A flange is used to mount the external RF antenna to the ion source. The RF antenna tubing is wound around the flange to form a coil. The flange is formed of a material, e.g. quartz, that is essentially transparent to the RF waves. The flange is attached to and forms a part of the plasma source chamber so that the RF waves emitted by the RF antenna enter into the inside of the plasma chamber and ionize a gas contained therein. The plasma ion source is typically a multi-cusp ion source. A converter can be included in the ion source to produce negative ions.
    Type: Application
    Filed: September 6, 2003
    Publication date: June 3, 2004
    Inventors: Ka-Ngo Leung, Sami K. Hahto, Sari T. Hahto
  • Publication number: 20040051053
    Abstract: A maskless micro-ion-beam reduction lithography (MMRL) system generates patterns of beamlets by switching individual beamlets on or off using a universal pattern generator which is positioned as the extraction electrode of the plasma source. Each aperture of the pattern generator is independently controlled to pass a beamlet. A multiplex addressing system to the individual apertures of the MMRL system is used to reduce the number of electrical connections. An additional layer of control electrodes is added. All apertures in each row of a first layer are connected to a single row address line. All apertures in each column of a second layer are connected to a single column address line. By using the combination of row and column lines, each aperture can be controlled.
    Type: Application
    Filed: May 22, 2003
    Publication date: March 18, 2004
    Inventors: William A. Barletta, Ka-Ngo Leung
  • Publication number: 20040036032
    Abstract: An electron beam system is based on a plasma generator in a plasma ion source with an accelerator column. The electrons are extracted from a plasma cathode in a plasma ion source, e.g. a multicusp plasma ion source. The beam can be scanned in both the x and y directions, and the system can be operated with multiple beamlets. A compact focused ion or electron beam system has a plasma ion source and an all-electrostatic beam acceleration and focusing column. The ion source is a small chamber with the plasma produced by radio-frequency (RF) induction discharge. The RF antenna is wound outside the chamber and connected to an RF supply. Ions or electrons can be extracted from the source. A multi-beam system has several sources of different species and an electron beam source.
    Type: Application
    Filed: August 30, 2002
    Publication date: February 26, 2004
    Inventors: Ka-Ngo Leung, Jani Reijonen, Arun Persaud, Qing Ji, Ximan Jiang
  • Publication number: 20040022341
    Abstract: A compact neutron generator has at its outer circumference a toroidal shaped plasma chamber in which a tritium (or other) plasma is generated. A RF antenna is wrapped around the plasma chamber. A plurality of tritium ion beamlets are extracted through spaced extraction apertures of a plasma electrode on the inner surface of the toroidal plasma chamber and directed inwardly toward the center of neutron generator. The beamlets pass through spaced acceleration and focusing electrodes to a neutron generating target at the center of neutron generator. The target is typically made of titanium tubing. Water is flowed through the tubing for cooling. The beam can be pulsed rapidly to achieve ultrashort neutron bursts. The target may be moved rapidly up and down so that the average power deposited on the surface of the target may be kept at a reasonable level. The neutron generator can produce fast neutrons from a T-T reaction which can be used for luggage and cargo interrogation applications.
    Type: Application
    Filed: April 8, 2003
    Publication date: February 5, 2004
    Inventors: Ka-Ngo Leung, Tak Pui Lou
  • Publication number: 20030234355
    Abstract: A neutron tube or generator is based on a RF driven plasma ion source having a quartz or other chamber surrounded by an external RF antenna. A deuterium or mixed deuterium/tritium (or even just a tritium) plasma is generated in the chamber and D or D/T (or T) ions are extracted from the plasma. A neutron generating target is positioned so that the ion beam is incident thereon and loads the target. Incident ions cause D-D or D-T (or T-T) reactions which generate neutrons. Various embodiments differ primarily in size of the chamber and position and shape of the neutron generating target. Some neutron generators are small enough for implantation in the body. The target may be at the end of a catheter-like drift tube. The target may have a tapered or conical surface to increase target surface area.
    Type: Application
    Filed: February 6, 2003
    Publication date: December 25, 2003
    Inventors: Ka-Ngo Leung, Tak Pui Lou, Jani Reijonen
  • Publication number: 20030218430
    Abstract: A radio frequency (RF) driven plasma ion source has an external RF antenna, i.e. the RF antenna is positioned outside the plasma generating chamber rather than inside. The RF antenna is typically formed of a small diameter metal tube coated with an insulator. A flange is used to mount the external RF antenna to the ion source. The RF antenna tubing is wound around the flange to form a coil. The flange is formed of a material, e.g. quartz, that is essentially transparent to the RF waves. The flange is attached to and forms a part of the plasma source chamber so that the RF waves emitted by the RF antenna enter into the inside of the plasma chamber and ionize a gas contained therein. The plasma ion source is typically a multi-cusp ion source.
    Type: Application
    Filed: May 22, 2003
    Publication date: November 27, 2003
    Inventors: Ka-Ngo Leung, Qing Ji, Stephen Wilde
  • Publication number: 20030168608
    Abstract: An extractor system for a plasma ion source has a single (first) electrode with one or more apertures, or a pair of spaced electrodes, a first or plasma forming electrode and a second or extraction electrode, with one or more aligned apertures. The aperture(s) in the first electrode (or the second electrode or both) have a counterbore on the downstream side (i.e. away from the plasma ion source or facing the second electrode). The counterbored extraction system reduces aberrations and improves focusing. The invention also includes an ion source with the counterbored extraction system, and a method of improving focusing in an extraction system by providing a counterbore.
    Type: Application
    Filed: February 13, 2003
    Publication date: September 11, 2003
    Inventors: Qing Ji, Keith Standiford, Tsu-Jae King, Ka-Ngo Leung
  • Publication number: 20030146803
    Abstract: A compact matching network couples an RF power supply to an RF antenna in a plasma generator. The simple and compact impedance matching network matches the plasma load to the impedance of a coaxial transmission line and the output impedance of an RF amplifier at radio frequencies. The matching network is formed of a resonantly tuned circuit formed of a variable capacitor and an inductor in a series resonance configuration, and a ferrite core transformer coupled to the resonantly tuned circuit. This matching network is compact enough to fit in existing compact focused ion beam systems.
    Type: Application
    Filed: February 1, 2002
    Publication date: August 7, 2003
    Inventors: Daniel S. Pickard, Ka-Ngo Leung