Patents by Inventor David Cheng

David Cheng 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: 6366103
    Abstract: A multiple test probe system is disclosed. The multiple test probe system includes a support and a mount pivotally coupled to the support. The mount is capable of pivoting to a number of testing positions. A number of probe assemblies are coupled to the mount and associated with a corresponding number of testing positions. The probe assemblies include a number of electrical contacts coupled to a number of wires in a probe bus regardless of a testing position of the mount. The multiple test probe system further includes an actuator coupled to the mount to cause the mount to move between the testing positions.
    Type: Grant
    Filed: July 6, 1999
    Date of Patent: April 2, 2002
    Inventor: David Cheng
  • Patent number: 6280581
    Abstract: An electroplating apparatus includes a cathode structure, an anode structure, a power supply, and a pressurized electrolyte source. The cathode structure is configured to engage a perimeter portion of a workpiece such as a semiconductor wafer, and the anode structure includes an outlet. The power supply is coupled between the cathode structure and the anode structure. The pressurized electrolyte source is coupled to the anode structure to provide an electrically continuous fluid jet of an electrolyte from the outlet to be directed to a surface of the workpiece that is to be electroplated. A method for electroplating a workpiece includes electrically engaging a perimeter portion of the workpiece with a cathode structure, and directing an electrically continuous fluid jet of electrolyte having positively charged ions towards a surface of the workpiece that is to be electroplated.
    Type: Grant
    Filed: December 29, 1998
    Date of Patent: August 28, 2001
    Inventor: David Cheng
  • Patent number: 6249342
    Abstract: Disclosed is a wafer handling and testing apparatus. The wafer handling and testing apparatus includes a support assembly, a wafer handling assembly, and a probe assembly. The support assembly is capable of supporting a wafer to be tested and is also capable of rotating the wafer for testing. The wafer handling assembly is arranged to move the wafer to and from the support assembly. The wafer handling assembly is capable of moving the along a first axis and a second axis. The first axis is preferably orthogonal to the second axis. The wafer probe is arranged to test the wafer when the wafer is placed on the support assembly.
    Type: Grant
    Filed: July 6, 1999
    Date of Patent: June 19, 2001
    Inventor: David Cheng
  • Patent number: 6164894
    Abstract: A wafer handling and testing apparatus and method include a station for supporting a wafer carrier, such as a cassette or pod, that holds one or more wafers, where the carrier can be moved in a z-direction. A wafer handling assembly is moveable in an x-direction and removes a wafer from the wafer carrier. The handling assembly includes an end effector and a sensor for detecting an edge of the wafer. A chuck includes a platform that is movable in a z-direction and is used to lift the wafer from the handling assembly and rotate the wafer so that the sensor maps the edge of the wafer. The wafer is then centered on the platform, lowered onto the chuck, and is tested by a test head that is preferably coupled to the handling assembly.
    Type: Grant
    Filed: November 4, 1997
    Date of Patent: December 26, 2000
    Inventor: David Cheng
  • Patent number: 6154041
    Abstract: A method and apparatus for measuring sheet resistance and thickness of thin films and substrates. A four-point probe assembly engages the surface of a film on a substrate, and the thickness of the substrate is determined from the point of contact between the probes and film. A measuring apparatus then outputs a voltage waveform which applies a voltage to probes of the probe assembly. An inverter inverts the voltage and provides the inverted voltage on another probe of the probe assembly, thus inducing a current in these probes of the four point probe and through the surface of the film. Two other probes measure a voltage in the film created by the current. The voltages on the current probes provide a voltage close to zero at the other probes, thus allowing these other probes to measure voltages with greater precision. The current created by the voltage waveform and the voltage created across the inner probes are measured for each voltage level of the waveform.
    Type: Grant
    Filed: February 26, 1999
    Date of Patent: November 28, 2000
    Inventor: David Cheng
  • Patent number: 6053688
    Abstract: A wafer handling apparatus and method includes a wafer carrier station for supporting a wafer carrier, such as an enclosed pod, that holds one or more wafers. A grounded interface panel is provided between the carrier station and a clean testing or processing environment. A z-movement mechanism moves the carrier station and the wafer carrier in a z-direction. A door opening mechanism removes a door from said carrier through a door opening in the interface panel. A handler mechanism includes a wafer holding device, such as a flat end effector, that moves into the wafer carrier at a separate access opening to load or unload a wafer to or from the wafer carrier. Wafer carriers holding different amounts of wafers can be used with no major structural changes to the apparatus.
    Type: Grant
    Filed: August 25, 1997
    Date of Patent: April 25, 2000
    Inventor: David Cheng
  • Patent number: 5922730
    Abstract: This invention relates to compounds which possess immunosuppressive and/or anti tumor and/or antinflammatory activity in vivo and/or inhibit thymocyte proliferation in vitro. These compounds are therefore useful in the treaiment of transplantation rejection, autoimmune diseases such as lupus, rheumatoid ardiritis, diabetes mellitus, multiple sclerosis and in the treatment of Candida albicans infections and also in treatment of diseases of inflammation. These compounds are represented by the formula below ##STR1## wherein W and Y are OR.sup.1 and X and Z together form a bond or W and X are OR.sup.2 and Y and Z together form a bond, wherein:R.sup.1 is selected from --(CH.sub.2).sub.n --Ar with a proviso that Ar is not phenyl,--(CH.sub.2 CH.sub.2 O).sub.n CH.sub.3 with a proviso that n is greater than one,--CH.sub.2 CH.sub.2 CH.sub.2 O(CH.sub.2 CH.sub.2 O).sub.m --CH.sub.3,--(CH.sub.2).sub.n --CH.sub.2 CH(OR.sup.3)CH.sub.2 OR.sup.4 where R.sup.3 and R.sup.4 are H, C.sub.1 -C.sub.10 alkyl, or R.sup.3 and R.sup.
    Type: Grant
    Filed: June 24, 1998
    Date of Patent: July 13, 1999
    Assignee: American Home Products Corporation
    Inventors: David Cheng Hu, Alexander Aleksey Greenfield, Thomas Joseph Caggiano, Craig Eugene Caufield
  • Patent number: 5917191
    Abstract: A method for measuring surface topography characterized by making multiple scans of the surface with a laser scanning unit and utilizing the multiple scans to create representations of the surface's topography. The surface topography data can also be used to calculate the compressive or tensile stress caused by a thin film applied to the surface of a semiconductor wafer. The apparatus of the present invention scans a laser beam across a surface in an x direction, and detects displacements of a reflected portion of the laser beam in a z direction. A pair of photodetectors are used to translate z direction displacements of the reflected beam into analog signals which are digitized and input into a microcomputer for analysis. The multiple scans of the surface are preferably accomplished by placing the workpiece on a pedestal which can be rotated to various angular positions.
    Type: Grant
    Filed: November 26, 1997
    Date of Patent: June 29, 1999
    Assignee: Ann F. Koo
    Inventor: David Cheng
  • Patent number: 5914611
    Abstract: A method and apparatus for measuring sheet resistance and thickness of thin films and substrates. A four-point probe assembly engages the surface of a film on a substrate, and the thickness of the substrate is determined from the point of contact between the probes and film. A measuring apparatus then outputs a voltage waveform which applies a voltage to probes of the probe assembly. An inverter inverts the voltage and provides the inverted voltage on another probe of the probe assembly, thus inducing a current in these probes of the four point probe and through the surface of the film. Two other probes measure a voltage in the film created by the current. The voltages on the current probes provide a voltage close to zero at the other probes, thus allowing these other probes to measure voltages with greater precision. The current created by the voltage waveform and the voltage created across the inner probes are measured for each voltage level of the waveform.
    Type: Grant
    Filed: August 12, 1997
    Date of Patent: June 22, 1999
    Inventor: David Cheng
  • Patent number: 5882165
    Abstract: An integrated modular multiple chamber vacuum processing system is disclosed. The system includes a load lock, may include an external cassette elevator, and an internal load lock wafer elevator, and also includes stations about the periphery of the load lock for connecting one, two or several vacuum process chambers to the load lock chamber. A robot is mounted within the load lock and utilizes a concentric shaft drive system connected to an end effector via a dual four-bar link mechanism for imparting selected R--.THETA. movement to the blade to load and unload wafers at the external elevator, internal elevator and individual process chambers. The system is uniquely adapted for enabling various types of IC processing including etch, deposition, sputtering and rapid thermal annealing chambers, thereby providing the opportunity for multiple step, sequential processing using different processes.
    Type: Grant
    Filed: September 10, 1997
    Date of Patent: March 16, 1999
    Assignee: Applied Materials, Inc.
    Inventors: Dan Maydan, Sasson Somekh, David Nin-Kou Wang, David Cheng, Masato Toshima, Isaac Harari, Peter D. Hoppe
  • Patent number: 5851299
    Abstract: An improved apparatus for CVD processing is described wherein a wafer mounted on a vertically movable susceptor beneath a gas outlet or showerhead is raised into contact with a shield ring which normally rests on a ring support in the chamber. The shield ring engages the frontside edge of the wafer, lifting the shield ring off its support, when the susceptor and the wafer are raised to a deposition position in the chamber. The shield ring, by engaging the frontside edge of the wafer, shields the edge of the top surface of the wafer, as well as the end edge and the backside of the wafer, during the deposition. Matching tapered edges, respectively, on the susceptor and the shield ring permit alignment of the shield ring with respect to the susceptor, and alignment of the wafer to the susceptor and the shield ring. Alignment means are also disclosed to circularly align the shield ring to its support in the chamber.
    Type: Grant
    Filed: March 25, 1994
    Date of Patent: December 22, 1998
    Assignee: Applied Materials, Inc.
    Inventors: David Cheng, Mei Chang
  • Patent number: 5769588
    Abstract: A workpiece loading interface is included within a workpiece processing system which processes workpieces, typically wafers, in a vacuum. The workpiece loading interface includes two separate chambers. Each chamber may be separately pumped down. Thus, while a first cassette of wafers, from a first chamber is being accessed, a second cassette of wafers may be loaded in the second chamber and the second chamber pumped down. Each chamber is designed to minimize intrusion to a clean room. Thus a door to each chamber has a mechanism which, when opening the door, first moves the door slightly away from an opening in the chamber and then the door is moved down parallel to the chamber. After the door is opened, a cassette of wafers is lowered through the opening in a motion much like a drawbridge. The cassette may be pivoted within the chamber when the position from which wafers are accessed from the cassette differs from the position from which the cassette is lowered out of the chamber.
    Type: Grant
    Filed: August 20, 1996
    Date of Patent: June 23, 1998
    Assignee: Applied Materials, Inc.
    Inventors: Masato M. Toshima, Phil M. Salzman, Steven C. Murdoch, Cheng Wang, Mark A. Stenholm, James Howard, Leonard Hall, David Cheng
  • Patent number: 5708279
    Abstract: A method for measuring surface topography characterized by making multiple scans of the surface with a laser scanning unit and utilizing the multiple scans to create representations of the surface's topography. The surface topography data can also be used to calculate the compressive or tensile stress caused by a thin film applied to the surface of a semiconductor wafer. The apparatus of the present invention scans a laser beam across a surface in an x direction, and detects displacements of a reflected portion of the laser beam in a z direction. A pair of photodetectors are used to translate z direction displacements of the reflected beam into analog signals which are digitized and input into a microcomputer for analysis. The multiple scans of the surface are preferably accomplished by placing the workpiece on a pedestal which can be rotated to various angular positions.
    Type: Grant
    Filed: March 11, 1996
    Date of Patent: January 13, 1998
    Assignee: Ann F. Koo
    Inventor: David Cheng
  • Patent number: 5696383
    Abstract: A method and apparatus for measuring the curvature of a wafer. The apparatus includes a laser head that includes multiple laser sources that each emit a laser beam, each beam having a different wavelength. A CPU selects one of the sources to emit a beam. The beam is directed through a lens within the laser head and onto a surface of a wafer. The beam is reflected from the surface of the wafer and detected by a detector. The present invention includes a motor to cause relative motion between the laser head and the wafer such that the beam scans across the surface of the wafer, relaying data to the detector and the CPU. The CPU calculates the curvature of the wafer surface using the scanned data. The CPU selects a different laser source to direct a beam having a different wavelength at the wafer surface to avoid destructive interference that may occur with previously-used wavelengths.
    Type: Grant
    Filed: May 9, 1996
    Date of Patent: December 9, 1997
    Assignee: Ann F. Koo
    Inventor: David Cheng
  • Patent number: 5691648
    Abstract: A method and apparatus for measuring sheet resistance and thickness of thin films and substrates. A four-point probe assembly engages the surface of a film on a substrate, and the thickness of the substrate is determined from the point of contact between the probes and film. A measuring apparatus then outputs a voltage waveform which applies a voltage to probes of the probe assembly. An inverter inverts the voltage and provides the inverted voltage on another probe of the probe assembly, thus inducing a current in these probes of the four point probe and through the surface of the film. Two other probes measure a voltage in the film created by the current. The voltages on the current probes provide a voltage close to zero at the other probes, thus allowing these other probes to measure voltages with greater precision. The current created by the voltage waveform and the voltage created across the inner probes are measured for each voltage level of the waveform.
    Type: Grant
    Filed: November 16, 1995
    Date of Patent: November 25, 1997
    Inventor: David Cheng
  • Patent number: 5670888
    Abstract: A method and apparatus for handling wafers. A wafer pick moves along a horizontal x-axis to unload a wafer from a cassette and position the wafer over a chuck. The chuck moves upwardly along a z-axis perpendicular to the surface of the wafer and lifts the wafer off the pick. The pick retracts through a slot in the chuck and a test probe moves along the x-axis to position itself over the wafer and chuck with reference to a calculated wafer center. The chuck then moves upwardly to engage the surface of the wafer with the probe. Wafer characteristics are tested at several test points located on a circle on the surface of the wafer by repeatedly lowering the chuck, rotating the chuck by a small amount, and raising the chuck to engage the wafer with the probe. The probe is then positioned to test another circle of points.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: September 23, 1997
    Inventor: David Cheng
  • Patent number: 5546179
    Abstract: A method and apparatus for mapping the edge and other characteristics of a wafer. A method for mapping the edge of a wafer includes steps of providing a sensor device over a surface of a wafer on a testing chuck. A beam of electromagnetic energy emitted by the sensor device is reflected from the surface of the wafer and its intensity is measured by the sensor device. The sensor device is focussed and is then positioned at the edge of the wafer by measuring the intensity of the reflected beam as the sensor device is moved. A changed intensity signifies that the sensor device is located at the edge of the wafer. The wafer is incrementally rotated and the intensity of the reflected beam is measured at multiple locations on the edge of the wafer to provide datapoints used in the edge mapping. The height of the wafer is mapped by moving the sensor device in a z direction perpendicular to the surface of the wafer. A focal distance is found where the reflected beam is at a maximum intensity.
    Type: Grant
    Filed: October 7, 1994
    Date of Patent: August 13, 1996
    Inventor: David Cheng
  • Patent number: 5532499
    Abstract: A method for measuring surface topography characterized by making multiple scans of the surface with a laser scanning unit and utilizing the multiple scans to create representations of the surface's topography. The surface topography data can also be used to calculate the compressive or tensile stress caused by a thin film applied to the surface of a semiconductor wafer. The apparatus of the present invention scans a laser beam across a surface in an x direction, and detects displacements of a reflected portion of the laser beam in a z direction. A pair of photodetectors are used to translate z direction displacements of the reflected beam into analog signals which are digitized and input into a microcomputer for analysis. The multiple scans of the surface are preferably accomplished by placing the workpiece on a pedestal which can be rotated to various angular positions.
    Type: Grant
    Filed: October 3, 1994
    Date of Patent: July 2, 1996
    Assignee: Ann F. Koo
    Inventor: David Cheng
  • Patent number: 5523582
    Abstract: A method and apparatus for measuring the curvature of a wafer. The apparatus includes a laser head that includes multiple laser sources that each emit a laser beam, each beam having a different wavelength. A CPU selects one of the sources to emit a beam. The beam is directed through a lens within the laser head and onto a surface of a wafer. The beam is reflected from the surface of the wafer and detected by a detector. The present invention includes a motor to cause relative motion between the laser head and the wafer such that the beam scans across the surface of the wafer, relaying data to the detector and the CPU. The CPU calculates the curvature of the wafer surface using the scanned data. The CPU selects a different laser source to direct a beam having a different wavelength at the wafer surface to avoid destructive interference that may occur with previously-used wavelengths.
    Type: Grant
    Filed: October 22, 1993
    Date of Patent: June 4, 1996
    Assignee: Ann F. Koo
    Inventor: David Cheng
  • Patent number: 5495178
    Abstract: A method and apparatus for measuring film thickness and sheet resistance. A four-point probe engages the surface of a film, and a measuring apparatus outputs a voltage waveform which induces a current in the outer probes of the four point probe and through the surface of the film. The two inner probes measure a voltage in the film created by the current. The current created by the voltage waveform and the voltage created across the inner probes are measured for each voltage level of the waveform. A sheet resistance of the film is calculated by taking a least square fit of the measured current and voltage and calculating the slope of the least square line fit. The sheet resistance is proportional to the slope of the least square line. The thickness of the film is calculated by dividing the film resistivity by the calculated sheet resistance.
    Type: Grant
    Filed: November 10, 1992
    Date of Patent: February 27, 1996
    Inventor: David Cheng