Method for the noncontacting measurement of the electrical conductivity of a lamella
Patent 4000458 Issued on December 28, 1976. Estimated Expiration Date: 
December 28, 1993. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
December 28, 1993. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3152303 3234461 3544893 3646436 InventorsAssigneeApplicationNo. 606365 filed on 08/21/1975US Classes:324/236, Oscillator type324/719With semiconductor or IC materials quality determination using conductivity effectsExaminersPrimary: Corcoran, Robert J.Attorney, Agent or FirmAbstractThe electrical conductivity of a lamella of conducting material (e.g., semiconductor wafers or metal films) is measured by introducing the lamella into the oscillatory magnetic field of the inductive element of the L-C tank circuit. The tank circuit is the frequency determining portion of an oscillator which is adjusted, upon sample introduction, to restore the magnitude of oscillation. With suitable choice of circuit parameters, the incremental current in the tank circuit is linearly proportional to the sheet conductivity of the lamella. An exemplary apparatus, operating at approximately 10 MHz with a 1 cm2 measurement area exhibited approximately 1% linearity over a 100 to 1 range of conductivity with a resolution of approximately one part in 104 with a limiting sensitivity of 1011 carriers per square cm. | |
