Patents by Inventor David J. Walker

David J. Walker 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).

  • Publication number: 20040163820
    Abstract: The present invention provides a bi-directional ball seat and method of use. In at least one embodiment, the present invention provides a fluid control system that includes a radial protrusion that can be selectively engaged and disengaged upstream and/or from a ball seat. For example, a ball can be placed in a passageway, engaged with a downstream ball seat, and the radial protrusion radially extended into the passageway distally from the seat relative to the ball. A reverse movement of the ball is restricted by the active radial movement of the radial protrusion into the passageway. The control system can be used to control a variety of tools associated with the well. Without limitation, the tools can include crossover tools, sleeves, packers, safety valves, separators, gravel packers, perforating guns, decoupling tools, valves, and other tools know to those with ordinary skills in the art.
    Type: Application
    Filed: February 24, 2003
    Publication date: August 26, 2004
    Applicant: BJ SERVICES COMPANY
    Inventors: Floyd Romaine Bishop, Marvin Bryce Traweek, Richard J. Ross, David J. Walker, Dewayne M. Turner
  • Patent number: 6771806
    Abstract: Disclosed is a method for detecting electrical defects on test structures of a semiconductor die. The test structures includes a plurality of electrically-isolated test structures and a plurality of non-electrically-isolated test structures. The test structures each has a portion located partially within a scan area. The portion of the test structures located within the scan area is scanned to obtain voltage contrast images of the test structures' portions. In a multi-pixel processor, the obtained voltage contrast images are analyzed to determine whether there are defects present within the test structures. In a preferred embodiment, the multi-pixel processor operates with pixel resolution sizes in a range of about 25 nm to 200 nm. In another aspect, the processor operates with a pixel size nominally equivalent to two times a width of the test structure's line width to maximize throughput at optimal signal to noise sensitivity.
    Type: Grant
    Filed: August 25, 2000
    Date of Patent: August 3, 2004
    Assignee: KLA-Tencor
    Inventors: Akella V. S. Satya, David L. Adler, Bin-Ming Benjamin Tsai, David J. Walker
  • Patent number: 6713759
    Abstract: An apparatus and method for inspecting a surface of a sample, particularly but not limited to a semiconductor device, using an electron beam is presented. The technique is called Secondary Electron Emission Microscopy (SEEM), and has significant advantages over both Scanning Electron Microscopy (SEM) and Low Energy Electron Microscopy (LEEM) techniques. In particular, the SEEM technique utilizes a beam of relatively high-energy primary electrons having a beam width appropriate for parallel, multi-pixel imaging. The electron energy is near a charge-stable condition to achieve faster imaging than was previously attainable with SEM, and charge neutrality unattainable with LEEM. The emitted electrons may be detected using a time delay integration detector.
    Type: Grant
    Filed: November 2, 2001
    Date of Patent: March 30, 2004
    Assignee: KLA Tencor Corporation
    Inventors: David L. Adler, David J. Walker, Fred Babian, Travis Wolfe
  • Patent number: 6681722
    Abstract: A collection element arrangement is provided having sleeve attachments near their lowermost ends which simulate a continuous sloping surface, or floor. The sleeve attachments upper surfaces forming the floor permit collected solids to flow down the sloping surface back into the furnace or reactor chamber. Stainless steel can be used for the collection elements and sleeve attachments since the floating floor accommodates differential thermal expansion between CFB components.
    Type: Grant
    Filed: October 18, 2002
    Date of Patent: January 27, 2004
    Assignee: The Babcock & Wilcox Company
    Inventors: Mikhail Maryamchik, Michael J. Szmania, David J. Walker, Donald L. Wietzke
  • Publication number: 20030205669
    Abstract: An apparatus and method for inspecting a surface of a sample, particularly but not limited to a semiconductor device, using an electron beam is presented. The technique is called Secondary Electron Emission Microscopy (SEEM), and has significant advantages over both Scanning Electron Microscopy (SEM) and Low Energy Electron Microscopy (LEEM) techniques. In particular, the SEEM technique utilizes a beam of relatively high-energy primary electrons having a beam width appropriate for parallel, multi-pixel imaging. The electron energy is near a charge-stable condition to achieve faster imaging than was previously attainable with SEM, and charge neutrality unattainable with LEEM. The emitted electrons may be detected using a time delay integration detector.
    Type: Application
    Filed: April 2, 2003
    Publication date: November 6, 2003
    Inventors: David L. Adler, David J. Walker, Fred Babian, Travis Wolfe
  • Publication number: 20030202913
    Abstract: A circulating fluidized bed (CFB) unit utilizing a mechanical dust collector located in a vertical flue above at least one heat exchange surface, and at least partially underneath the floor of a non-vertical flue, includes a plurality of individual collection elements each having a downward bottom outlet for a flow of cleaned gas conveyed through the collection elements.
    Type: Application
    Filed: April 30, 2002
    Publication date: October 30, 2003
    Inventors: Mikhail Maryamchik, Felix Belin, David J. Walker, Donald L. Wietzke
  • Patent number: 6636064
    Abstract: Disclosed is a semiconductor die having an upper layer and a lower layer. The die includes a lower test structure formed in the lower metal layer of the semiconductor die. The lower conductive test structure has a first end and a second end, wherein the first end is coupled to a predetermined voltage level. The die also has an insulating layer formed over the lower metal layer and an upper test structure formed in the upper metal layer of the semiconductor die. The upper conductive test structure is coupled with the second end of the lower conductive test structure, and the upper metal layer being formed over the insulating layer. The die further includes at least one probe pad coupled with the upper test structure. Preferably, the first end of the lower test structure is coupled to a nominal ground potential. In another implementation, the upper test structure is a voltage contrast element. In another embodiment, a semiconductor die having a scanning area is disclosed.
    Type: Grant
    Filed: August 25, 2000
    Date of Patent: October 21, 2003
    Assignee: KLA-Tencor
    Inventors: Akella V. S. Satya, David L. Adler, Neil Richardson, Kurt H. Weiner, David J. Walker
  • Patent number: 6633174
    Abstract: Disclosed is a method of inspecting a sample. The method includes moving to a first field associated with a first group of test structures. The first group of test structures are partially within the first field. The method further includes scanning the first field to determine whether there are any defects present within the first group of test structures. When it is determined that there are defects within the first group of test structures, the method further includes repeatedly stepping to areas and scanning such areas so as to determine a specific defect location within the first group of test structures. A suitable test structure for performing this method is also disclosed.
    Type: Grant
    Filed: August 25, 2000
    Date of Patent: October 14, 2003
    Assignee: KLA-Tencor
    Inventors: Akella V. S. Satya, David L. Adler, Neil Richardson, Gustavo A. Pinto, David J. Walker
  • Publication number: 20030155927
    Abstract: Disclosed is a method of inspecting a sample. The sample is scanned in a first direction with at least one particle beam. The sample is scanned in a second direction with at least one particle beam. The second direction is at an angle to the first direction. The number of defects per an area of the sample are found as a result of the first scan, and the position of one or more of the found defects is determined from the second scan. In a specific embodiment, the sample includes a test structure having a plurality of test elements thereon. A first portion of the test elements is exposed to the beam during the first scan to identify test elements having defects, and a second portion of the test elements is exposed during the second scan to isolate and characterize the defect.
    Type: Application
    Filed: March 13, 2003
    Publication date: August 21, 2003
    Applicant: KLA Tencor Technologies Corporation
    Inventors: Gustavo A. Pinto, Brian C. Leslie, David L. Adler, Akella V.S. Satya, Robert Thomas Long, David J. Walker
  • Publication number: 20030136095
    Abstract: A separator array for a furnace has large scale collection elements which can be formed from water-cooled tube walls and permit walk-through inspection and repair. The collection elements have direct impact surfaces, indirect impact surfaces and stagnation retainer surfaces. The array uses fewer, but larger collection elements than known separator arrays to provide at least the same solids collection efficiency while permitting the use of lower cost materials and easier inspection and repair.
    Type: Application
    Filed: January 24, 2002
    Publication date: July 24, 2003
    Inventors: David J. Walker, Mikhail Maryamchik, Donald L. Wietzke
  • Publication number: 20030096436
    Abstract: Disclosed is a semiconductor die having a scanning area. The semiconductor die includes a first plurality of test structures wherein each of the test structures in the first plurality of test structures is located entirely within the scanning area. The semiconductor die further includes a second plurality of test structures wherein each of the test structures in the first plurality of test structures is located only partially within the scanning area. The test structures are arranged so that a scan of the scanning area results in detection of defects outside of the scanning area.
    Type: Application
    Filed: January 7, 2003
    Publication date: May 22, 2003
    Applicant: KLA-Tencor Technologies Corporation
    Inventors: Akella V. S. Satya, Gustavo A. Pinto, David L. Adler, Robert Thomas Long, Neil Richardson, Kurt H. Weiner, David J. Walker, Lynda C. Mantalas
  • Patent number: 6566885
    Abstract: A sample is inspected. The sample is scanned in a first direction with at least one particle beam. The sample is scanned in a second direction with at least one particle beam. The second direction is at an angle to the first direction. The number of defects per an area of the sample are found as a result of the first scan, and the position of one or more of the found defects is determined from the second scan. In a specific embodiment, the sample includes a test structure having a plurality of test elements thereon. A first portion of the test elements is exposed to the beam during the first scan to identify test elements having defects, and a second portion of the test elements is exposed during the second scan to isolate and characterize the defect.
    Type: Grant
    Filed: August 25, 2000
    Date of Patent: May 20, 2003
    Assignee: KLA-Tencor
    Inventors: Gustavo A. Pinto, Brian C. Leslie, David L. Adler, Akella V. S. Satya, Robert Thomas Long, David J. Walker
  • Patent number: 6532905
    Abstract: A circulating fluidized bed (CFB) boiler has one or more bubbling fluidized bed enclosures containing heating surfaces and located within a lower portion of the CFB boiler to provide a compact, efficient design with a reduced footprint area. The heating surfaces are provided within the bubbling fluidized bed located above a CFB grid and/or in a moving packed bed below the CFB grid inside the lower portion of the CFB boiler. Solids in the bubbling fluidized bed are maintained in a slow bubbling fluidized bed state by separately controlled fluidization gas supplies. Separately controlled fluidization gas is used to control bed level in the bubbling fluidized beds or to control the throughput of solids through the bubbling fluidized beds. Solids ejected from the bubbling fluidized beds can be returned directly into the surrounding CFB environment of the CFB boiler, or purged from the system for disposal or recycle back into the CFB.
    Type: Grant
    Filed: July 17, 2001
    Date of Patent: March 18, 2003
    Assignee: The Babcock & Wilcox Company
    Inventors: Felix Belin, Mikhail Maryamchik, Sundara M. Kavidass, David J. Walker, Donald L. Wietzke
  • Patent number: 6528818
    Abstract: Disclosed is a semiconductor die having a scanning area. The semiconductor die includes a first plurality of test structures wherein each of the test structures in the first plurality of test structures is located entirely within the scanning area. The semiconductor die further includes a second plurality of test structures wherein each of the test structures in the first plurality of test structures is located only partially within the scanning area. The test structures are arranged so that a scan of the scanning area results in detection of defects outside of the scanning area.
    Type: Grant
    Filed: August 25, 2000
    Date of Patent: March 4, 2003
    Assignee: KLA-Tencor
    Inventors: Akella V. S. Satya, Gustavo A. Pinto, David L. Adler, Robert Thomas Long, Neil Richardson, Kurt H. Weiner, David J. Walker, Lynda C. Mantalas
  • Patent number: 6524873
    Abstract: Disclosed is, a method for detecting electrical defects on test structures of a semiconductor die. The semiconductor die includes a plurality of electrically-isolated test structures and a plurality of non-electrically-isolated test structures. Voltages are established for the plurality of electrically-isolated test structures. These voltages are different than the voltages of the plurality of non-electrically-isolated test structures. A region of the semiconductor die is continuously inspected in a first direction thereby obtaining voltage contrast data indicative of whether there are defective test structures. The voltage contrast data is analyzed to determine whether there are one or more defective test structures.
    Type: Grant
    Filed: August 25, 2000
    Date of Patent: February 25, 2003
    Assignee: KLA-Tencor
    Inventors: Akella V. S. Satya, David L. Adler, Bin-Ming Benjamin Tsai, Neil Richardson, David J. Walker
  • Publication number: 20030015150
    Abstract: A circulating fluidized bed (CFB) boiler has one or more bubbling fluidized bed enclosures containing heating surfaces and located within a lower portion of the CFB boiler to provide a compact, efficient design with a reduced footprint area. The heating surfaces are provided within the bubbling fluidized bed located above a CFB grid and/or in a moving packed bed below the CFB grid inside the lower portion of the CFB boiler. Solids in the bubbling fluidized bed are maintained in a slow bubbling fluidized bed state by separately controlled fluidization gas supplies. Separately controlled fluidization gas is used to control bed level in the bubbling fluidized beds or to control the throughput of solids through the bubbling fluidized beds. Solids ejected from the bubbling fluidized beds can be returned directly into the surrounding CFB environment of the CFB boiler, or purged from the system for disposal or recycle back into the CFB.
    Type: Application
    Filed: July 17, 2001
    Publication date: January 23, 2003
    Inventors: Felix Belin, Mikhail Maryamchik, Sundara M. Kavidass, David J. Walker, Donald L. Wietzke
  • Patent number: 6500221
    Abstract: Apparatus for separating solids from flue gas in a circulating fluidized bed (CFB) boiler includes plural vertical, impact type particle separators made of cooling tubes located within the CFB in a plurality of staggered rows. One embodiment employs a plurality of stacked, slip fit elements having apertures which accept the cooling tubes. The slip fit elements cooperate with one another to form a collecting channel, typically U-shaped, which separates particles from flue gases conveyed across the particle separators. Shiplap joints in between the individual slip fit elements prevent gas and solids from leaking therebetween and allow for thermal expansion. Alternatively, the impact type particle separators include cooling tubes connected to one another to form a unitary structure. Pin studs welded to the cooling tubes and covered with a coating of refractory; ceramic tiles; metal or ceramic spray coatings; metal or ceramic castings; weld overlay; and/or shields provide erosion resistance.
    Type: Grant
    Filed: May 25, 2001
    Date of Patent: December 31, 2002
    Assignee: The Babcock & Wilcox Company
    Inventors: David J. Walker, Mikhail Maryamchik, Sundara M. Kavidass, Felix Belin, Kiplin C. Alexander, David E. James, David R. Gibbs, Donald L. Wietzke
  • Patent number: 6491000
    Abstract: A tube wall, division wall, or wing wall section (10) for a circulating fluidized bed boiler with improved erosion resistant characteristics has a reduced diameter tube section (40) adjacent the refractory covered by an abrasion resistant refractory tile (60). The refractory tile (60) is mounted to the reduced diameter tube section (40) with the upper edge of the refractory tile outside of or not extending beyond a solids fall line of solids in the fluidized bed to eliminate exposed discontinuities.
    Type: Grant
    Filed: November 6, 2001
    Date of Patent: December 10, 2002
    Assignee: The Babcock & Wilcox Company
    Inventors: David J. Walker, Donald L. Wietzke, Gary L. Anderson, Richard F. Romansky, Jr.
  • Patent number: 6454824
    Abstract: Apparatus for separating solids from flue gas in a circulating fluidized bed (CFB) boiler comprises plural vertical, impact type particle separators located within the CFB in a plurality of staggered rows. The impact type particle separators employ hung elements supported from fluid-cooled tubes which form a collecting channel, typically U-shaped, which separates particles from flue gases conveyed across the particle separators. By separating the support function from the collection shape required by functional performance considerations, the strength requirements of the material used to form the collection shape are reduced and the strength of the material from which the fluid-cooled support is made is much higher due to the lower operating temperature of the material comprising the fluid-cooled support, thereby permitting the use of lower cost materials.
    Type: Grant
    Filed: May 25, 2001
    Date of Patent: September 24, 2002
    Assignee: The Babcock & Wilcox Company
    Inventors: Mikhail Maryamchik, Kiplin C. Alexander, Felix Belin, David R. Gibbs, David J. Walker, Donald L. Wietzke
  • Publication number: 20020104964
    Abstract: An apparatus and method for inspecting a surface of a sample, particularly but not limited to a semiconductor device, using an electron beam is presented. The technique is called Secondary Electron Emission Microscopy (SEEM), and has significant advantages over both Scanning Electron Microscopy (SEM) and Low Energy Electron Microscopy (LEEM) techniques. In particular, the SEEM technique utilizes a beam of relatively high-energy primary electrons having a beam width appropriate for parallel, multi-pixel imaging. The electron energy is near a charge-stable condition to achieve faster imaging than was previously attainable with SEM, and charge neutrality unattainable with LEEM. The emitted electrons may be detected using a time delay integration detector.
    Type: Application
    Filed: November 2, 2001
    Publication date: August 8, 2002
    Inventors: David L. Adler, David J. Walker, Fred Babian, Travis Wolfe