Patents Assigned to Four Dimensions, Inc.
  • Patent number: 7714596
    Abstract: Sheet resistance, junction leakage and contact conductivity of a semiconductor layer, associated with an ultra-shallow junction layer or metal film are measured by contacting the surface with a plurality of probes. The probes can be used, in conjunction with a four-point probe system, to determine sheet resistivity. Junction leakage through an ultra-shallow junction is determined by establishing a reverse bias across the junction set at a predetermined voltage value, measuring through a first probe a total junction current conduction value, measuring through second, third, and fourth probes a plurality of voltage values. The junction leakage value is then directly computed based on the sheet resistivity value, reverse bias potential, wafer radius, and the measured voltage values. Contact conductivity between a metal film and semiconductor layer can be similarly directly computed.
    Type: Grant
    Filed: December 14, 2007
    Date of Patent: May 11, 2010
    Assignee: Four Dimensions Inc.
    Inventors: James T. C. Chen, Dimitar B. Dimitrov
  • Patent number: 7253649
    Abstract: An upward facing probing mechanism using mercury probe contacts for accurate automatic multi-site measurements of a semiconductor wafer, especially of ultra-shallow ion implanted layers on a semiconductor wafer held top surface facing downward. A fixed force is applied to the wafer regardless of the thickness of the wafer through the of use of a regulated pressure piston. Incorporated are a plurality of spring-loaded rod assemblies to support the floating probe head to position the probe head face into full contact with the wafer surface accurately placing all mercury contacts on the surface of the wafer regardless of the inclination of the wafer as a result of the even support of the probe head by the spring-loaded rod assemblies. Included is a mechanism to refresh the mercury contacts for each probing with full containment and recovery of the mercury used in each probing.
    Type: Grant
    Filed: January 31, 2006
    Date of Patent: August 7, 2007
    Assignee: Four Dimensions, Inc,
    Inventor: James T. Chen
  • Patent number: 6810758
    Abstract: Provided is a test system and method that permits automatically interchanging a plurality of tools to seamlessly perform various functions on a sample. Each tool is mounted in an assembly and the sample is mounted on a chuck. A path is defined in a plane along which a carriage on which the tool assemblies are mounted is transported with the tools each positioned in the same attitude with respect to, and distance from, that path. The carriage is transported along the path to a position where one of the tools is adjacent the chuck which is rotated, if necessary, to position a desired point of interest on the sample immediately adjacent the tool. Once positioned, the tool engages the sample to perform a test. Following testing, the tool is disengaged from the sample and the process repeated as necessary for each additional test to be performed on the sample.
    Type: Grant
    Filed: July 16, 2002
    Date of Patent: November 2, 2004
    Assignee: Four Dimensions, Inc.
    Inventors: James T. Chen, Gong Wang
  • Patent number: 6435045
    Abstract: Provided is a test system and method that permits automatically interchanging a plurality of tools to seamlessly perform various functions on a sample. Each tool is mounted in an assembly and the sample is mounted on a chuck. A path is defined in a plane along which the chuck is transported with the tools each positioned in the same attitude with respect to, and distance from, that path. The chuck is transported along the path to a position adjacent one of the tools and rotated, if necessary, to position a point of interest on the sample immediately adjacent the tool. Once positioned, the tool engages the sample to perform a test. Following testing, the tool is disengaged from the sample and the process repeated as necessary for each additional test to be performed on the sample.
    Type: Grant
    Filed: September 2, 1999
    Date of Patent: August 20, 2002
    Assignee: Four Dimensions, Inc.
    Inventors: James T. Chen, Gong Wang