Method and apparatus for releasing a semiconductor wafer from an electrostatic clamp
Patent 5474614 Issued on December 12, 1995. Estimated Expiration Date: 
June 10, 2014. 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.
June 10, 2014. 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 ReferencesElectrostatic chuck having tapered electrodes Electrostatic chuck Patent #: 5213349 InventorAssigneeApplicationNo. 257993 filed on 06/10/1994US Classes:118/728, Work support269/8, MAGNETIC HOLDER361/234PinningExaminersPrimary: Chaudhuri, OlikAssistant: Dutton, Brian Attorney, Agent or FirmInternational ClassesC23C 016/00B25B 011/00 H01G 003/00 H01T 023/00 AbstractA method and apparatus is provided for effectively releasing a semiconductor wafer (36) from a deactivated electrostatic clamp (20) by diffusing a neutralizing gas into the space between the clamping surface of the electrostatic clamp and the surface of the wafer, generating an ionizing voltage with an alternating polarity, and applying the alternating polarity ionizing voltage to the diffusing gas to neutralize the residual electrostatic charges remaining on the surfaces of the clamp (20) and the wafer (36).Other References
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