Patents by Inventor Kenneth H. Purser
Kenneth H. Purser 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).
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Patent number: 7365340Abstract: The present invention comprehends a compact and economical apparatus for producing high intensities of a wide variety of wanted positive and negative molecular and atomic ion beams that have been previously impossible to previously produce at useful intensities. In addition, the invention provides a substantial rejection of companion background ions that are frequently simultaneously emitted with the wanted ions. The principle underlying the present invention is resonance ionization-transfer where energy differences between resonant and non-resonant processes are exploited to enhance or attenuate particular charge-changing processes. This new source technique is relevant to the fields of Accelerator Mass Spectroscopy; Molecular Ion Implantation; Generation of Directed Neutral Beams; and Production of Electrons required for Ion Beam Neutralization within magnetic fields.Type: GrantFiled: July 20, 2005Date of Patent: April 29, 2008Assignee: Varian Semiconductor Equipment Associates, Inc.Inventors: Kenneth H. Purser, Albert E. Litherland, Norman L. Turner
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Patent number: 7351984Abstract: A method and apparatus satisfying growing demands for improving the precision of angle of incidence of implanting ions that impact a semiconductor wafer and the precision of ribbon ion beams for uniform doping of wafers as they pass under an ion beam. The method and apparatus are directed to the design and combination together of novel magnetic ion-optical transport elements for implantation purposes. The design of the optical elements makes possible: (1) Broad-range adjustment of the width of a ribbon beam at the work piece; (2) Correction of inaccuracies in the intensity distribution across the width of a ribbon beam; (3) Independent steering about both X and Y axes; (4) Angle of incidence correction at the work piece; and (5) Approximate compensation for the beam expansion effects arising from space charge. In a practical situation, combinations of the elements allow ribbon beam expansion between source and work piece to 350 millimeter, with good uniformity and angular accuracy.Type: GrantFiled: April 5, 2007Date of Patent: April 1, 2008Assignee: Varian Semiconductor Equipment Associates, Inc.Inventors: Kenneth H. Purser, Harald A. Enge, Norman L. Turner
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Patent number: 7301156Abstract: A method and apparatus satisfying growing demands for improving the precision of angle of incidence of implanting ions that impact a semiconductor wafer and the precision of ribbon ion beams for uniform doping of wafers as they pass under an ion beam. The method and apparatus are directed to the design and combination together of novel magnetic ion-optical transport elements for implantation purposes. The design of the optical elements makes possible: (1) Broad-range adjustment of the width of a ribbon beam at the work piece; (2) Correction of inaccuracies in the intensity distribution across the width of a ribbon beam; (3) Independent steering about both X and Y axes; (4) Angle of incidence correction at the work piece; and (5) Approximate compensation for the beam expansion effects arising from space charge. In a practical situation, combinations of the elements allow ribbon beam expansion between source and work piece to 350 millimeter, with good uniformity and angular accuracy.Type: GrantFiled: June 16, 2005Date of Patent: November 27, 2007Inventors: Kenneth H. Purser, Harald A. Enge, Norman L. Turner
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Publication number: 20070170369Abstract: A technique for improving uniformity of a ribbon beam is disclosed. In one particular exemplary embodiment, an apparatus may comprise a first corrector-bar assembly and a second corrector-bar assembly, wherein the second corrector-bar assembly is located at a predetermined distance from the first corrector-bar assembly. Each of a first plurality of coils in the first corrector-bar assembly may be individually excited to deflect at least one beamlet in the ribbon beam, thereby causing the beamlets to arrive at the second corrector-bar assembly in a desired spatial spread. Each of a second plurality of coils in the second corrector-bar assembly may be individually excited to further deflect one or more beamlets in the ribbon beam, thereby causing the beamlets to exit the second corrector-bar assembly at desired angles.Type: ApplicationFiled: September 29, 2006Publication date: July 26, 2007Applicant: Varian Semiconductor Equipment Associates, Inc.Inventors: Kenneth H. Purser, Atul Gupta
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Patent number: 6933507Abstract: A method and apparatus satisfying growing demands for improving the precision of angle of incidence of implanting ions that impact a semiconductor wafer and the precision of ribbon ion beams for uniform doping of wafers as they pass under an ion beam. The method and apparatus are directed to the design and combination together of novel magnetic ion-optical transport elements for implantation purposes. The design of the optical elements makes possible: (1) Broad-range adjustment of the width of a ribbon beam at the work piece; (2) Correction of inaccuracies in the intensity distribution across the width of a ribbon beam; (3) Independent steering about both X and Y axes; (4) Angle of incidence correction at the work piece; and (5) Approximate compensation for the beam expansion effects arising from space charge. In a practical situation, combinations of the elements allow ribbon beam expansion between source and work piece to 350 millimeter, with good uniformity and angular accuracy.Type: GrantFiled: July 15, 2003Date of Patent: August 23, 2005Inventors: Kenneth H. Purser, Harald A. Enge, Norman L. Turner
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Publication number: 20040149926Abstract: Methods and apparatus are disclosed for rapidly providing for a large number of closely spaced points within an area at right angle to the central trajectory of an ion beam data concerning intensity variations, emittance variations and angular variations of elementary beamlets with respect to the central beam trajectory. The technology is particular applicable to the application and control of ribbon beams used for semiconductor implantation.Type: ApplicationFiled: December 11, 2003Publication date: August 5, 2004Inventors: Kenneth H. Purser, Carl J. Russo, Norman L. Turner
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Publication number: 20040097058Abstract: A method and apparatus satisfying growing demands for improving the precision of angle of incidence of implanting ions that impact a semiconductor wafer and the precision of ribbon ion beams for uniform doping of wafers as they pass under an ion beam. The method and apparatus are directed to the design and combination together of novel magnetic ion-optical transport elements for implantation purposes. The design of the optical elements makes possible: (1) Broad-range adjustment of the width of a ribbon beam at the work piece; (2) Correction of inaccuracies in the intensity distribution across the width of a ribbon beam; (3) Independent steering about both X and Y axes; (4) Angle of incidence correction at the work piece; and (5) Approximate compensation for the beam expansion effects arising from space charge. In a practical situation, combinations of the elements allow ribbon beam expansion between source and work piece to 350 millimeter, with good uniformity and angular accuracy.Type: ApplicationFiled: July 15, 2003Publication date: May 20, 2004Inventors: Kenneth H. Purser, Harald A. Enge, Norman L. Turner
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Publication number: 20030197133Abstract: An apparatus for controlling the motion of a workpiece in a vacuum chamber. The work piece is supported in vacuum on a pedestal or platen, containing an electrostatic chuck for holding and clamping the workpiece.Type: ApplicationFiled: April 18, 2003Publication date: October 23, 2003Inventors: Norman L. Turner, Kenneth H. Purser
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Patent number: 5907158Abstract: Ion implanter having at least two independent ion generating systems coupled to a single scanning end station. In a preferred embodiment one of the ion generating systems generates ions approximately in the 3-80 keV range and the other system generates ions approximately in the 80-3,000 keV range. The scanning end station may be employ magnetic, electrostatic, or mechanical scanning. This invention has particular relevance for the controlled doping of semiconducting materials and flat panel displays units in which doping may be needed for the production of micro-electronic devices, the sub-circuit crystal damage that is useful for gettering unwanted impurity atoms and for the development of etch pits in flat panel displays. The disclosed apparatus makes possible a variety of chained implants at different energies using the same mask.Type: GrantFiled: May 14, 1997Date of Patent: May 25, 1999Assignee: Ebara CorporationInventors: Mehran Nasser-Ghodsi, Andrew Wittkower, Hilton F. Glavish, Kenneth H. Purser, Gaylord C. Noblitt, III
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Patent number: 5828070Abstract: A system and method for conductively and/or convectively transferring heat away from a workpiece that has been processed by a processing system, such as an ion implantation system. The conductive transfer of heat from the workpiece is effectuated by disposing the workpiece in relatively close proximity with a floor of a loadlock, which is maintained at a relatively cool temperature. The chamber pressure is disposed at a selected pressure by a pressure regulator and a vacuum pressure is applied to the backside of the workpiece closest to draw the workpiece into contact with the chamber floor, thereby effecting heat transfer from the workpiece to the cooling surface.Type: GrantFiled: November 26, 1996Date of Patent: October 27, 1998Assignee: Eaton CorporationInventors: Adam A. Brailove, Peter H. Rose, Julian G. Blake, Zhongmin Yang, Kenneth H. Purser
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Patent number: 5825038Abstract: A high throughput ion implantation system that rapidly and efficiently processes large quantities of flat panel displays. The ion implantation system has an ion chamber generating a stream of ions, a plasma electrode having an elongated slot with a high aspect ratio for shaping the stream of ions into a ribbon beam, and an electrode assembly for directing the stream of ions towards a workpiece. The plasma electrode can include a split extraction system having a plurality of elongated slots oriented substantially parallel to each other. The ion implantation system can also have a diffusing system for homogenizing the ion stream. Various exemplary diffusing systems include an apertured plate having an array of openings, diffusing magnets, diffusing electrodes, and dithering magnets.Type: GrantFiled: November 26, 1996Date of Patent: October 20, 1998Assignee: Eaton CorporationInventors: Julian G. Blake, Kenneth H. Purser, Adam A. Brailove, Peter H. Rose, Barbara J. Hughey
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Patent number: 5719403Abstract: A method and apparatus for the direct current acceleration and scanning of ions of all species to energies as high as a few million electron volts (MeV). These method and apparatus have particular relevance for the controlled doping of semiconductor materials and flat panel display units. The apparatus employs high velocity neutral beams of dopant atoms to deliver atoms to the high voltage terminal where they are converted to positive ions having a low electric rigidity. This low electric rigidity makes possible a compact charge state analyzer prior to final positive ion acceleration together with compact electrostatic scanning of the ions for individual wafer implantation at MeV energies. This technology makes possible a compact implanter system.Type: GrantFiled: February 21, 1997Date of Patent: February 17, 1998Inventor: Kenneth H. Purser
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Patent number: 5693939Abstract: This invention relates to a method and apparatus for the direct current acceleration of ions of all species to energies as high as a few million electron volts (MeV). This invention has particular relevance for the controlled doping of semiconductor materials and flat panel display units where MeV doping may be needed for the production of deep wells, isolation layers, the sub-circuit crystal damage that is useful for gettering unwanted impurity atoms and for the developments of etch pits. The apparatus disclosed uses an acceleration procedure that employs high velocity neutral beams of dopant atoms to deliver atoms to the high voltage terminal of a dc. accelerator where they are converted to positive polarity and accelerated in a manner similar to that of a single ended dc accelerator. The disclosed method permits of a compact apparatus that does not require the use of negative ions, as do tandem-based accelerators, or the large power consumption of rf linacs and radio frequency quadrupoles.Type: GrantFiled: July 3, 1996Date of Patent: December 2, 1997Inventor: Kenneth H. Purser
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Patent number: 5661299Abstract: Accelerator mass spectrometry (AMS) demonstrates more than a million times greater sensitivity for .sup.14 C atoms and a thousand times greater sensitivity for tritium atoms than is possible using classical beta particle detection. This improved sensitivity can be used to help understand the role that chemical pollutants at ambient concentrations play in metabolic processes and in initiating mutations. Such measurements are critical to understanding many biomedical processes and establishing relevant environmental regulations. The present invention comprehends a device that can be used for the direct detection of either carbon-14 or tritium atoms. Unique features are that the highest acceleration voltage needed is only about 200 kilovolts and that vacuum insulation can be used to provide the necessary electrical insulation, rather than the high pressure sulfur hexafluoride gas, that is a characteristic of most electrostatic accelerators.Type: GrantFiled: June 25, 1996Date of Patent: August 26, 1997Assignee: High Voltage Engineering Europa B.V.Inventor: Kenneth H. Purser
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Patent number: 5621209Abstract: This invention relates to the detection of the radioisiotope carbon-14 using Accelerator Mass Spectrometry (AMS). This invention has particular relevance to the fields of attomole level (10.sup.-18 molar) tracking of chemicals in biomedicine and the environment, the testing of new classes of medical drugs, the whereabouts of chemotherapy agents within cancer patients, the elimination of the need to store and dispose of low-level carbon-14 nuclear waste and neutron exposure monitoring around nuclear reactors.Type: GrantFiled: April 10, 1995Date of Patent: April 15, 1997Assignee: High Voltage Engineering Europa B.V.Inventor: Kenneth H. Purser
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Patent number: 5569915Abstract: A highly sensitive spectrometer system having inherently low backgrounds is described. In this new molecular accelerator mass spectrometry procedure, negative molecules containing the isotope of interest are accelerated using a tandem accelerator. Subsequent electron stripping and analysis stages outside of the accelerator fragment the molecules and eliminate mass upon charge ambiguities. The combination results in a cost effective accelerator mass spectrometer with high sensitivity and low backgrounds.Type: GrantFiled: April 14, 1995Date of Patent: October 29, 1996Inventors: Kenneth H. Purser, Linas R. Kilius, Albert E. Litherland, John C. Rucklidge, Xiaolei Zhao
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Patent number: 5438194Abstract: Samples are directed into a liquid or gas chromatograph, and the output from the liquid or gas chromatograph is directed into the ion source of an accelerator mass spectrometry system so as to provide an ultra-sensitive identifier of molecules in the samples.Type: GrantFiled: July 30, 1993Date of Patent: August 1, 1995Assignee: High Voltage Engineering Europa B.V.Inventors: Reijer Koudijs, Marcel M. Mulder, Kenneth H. Purser, Frans W. Saris
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Patent number: 5391870Abstract: Compact and economical apparatus for use in accelerator mass spectrometry for mass selection and attenuation of each isotope by a predetermined fraction that is necessary to permit isotope sequencing through the accelerator stage, by a rotating shutter whose attenuation characteristics are defined by its mechanical shape.Type: GrantFiled: September 1, 1993Date of Patent: February 21, 1995Assignee: High Voltage Engineering Europa B.V.Inventor: Kenneth H. Purser
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Patent number: 5247263Abstract: An injection system for a tandem accelerator with equal transmission efficiency over a broad energy range includes means for shielding the injected ion beam from the electric field within the grounded end of the low-energy acceleration tube and injecting the ion beam into the low-energy acceleration tube sequentially through a narrow acceleration gap and the shielded region.Type: GrantFiled: May 6, 1991Date of Patent: September 21, 1993Assignee: High Voltage Engineering Europa B.V.Inventor: Kenneth H. Purser
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Patent number: 5237174Abstract: The capability of an existing AMS system is expanded to provide capability for identification of .sup.36 Cl atoms to the exclusion of .sup.36 S atoms by adding to such a system a booster accelerator having an ionization detector in its high-voltage terminal capable of measuring dE/dx as a function of penetration depth. The voltage of the direct-voltage accelerators employed need not exceed voltages of the order of 3 million volts, even though the ions detected have energies in excess of 36 million electron volts.Type: GrantFiled: October 9, 1991Date of Patent: August 17, 1993Assignee: High Voltage Engineering EuropaInventor: Kenneth H. Purser