GAS BEARING ELECTROSTATIC CHUCK
First Claim
1. An electrostatic clamp for selectively maintaining a position of a workpiece, the electrostatic clamp comprising:
- a clamping plate having a clamping surface associated with the workpiece, wherein the clamping plate has a central region and an annulus region defined therein, and wherein the annulus region is generally disposed about a periphery of the central region;
a plurality of gas supply orifices defined in the central region of the clamping plate, wherein the plurality of gas supply orifices are in fluid communication with a pressurized gas supply, and wherein the pressurized gas supply is configured to provide a cushion of gas between the clamping surface and the workpiece in the central region of the clamping plate via the plurality of gas supply orifices;
one or more gas return orifices defined in one or more of the central region and annulus region of the clamping plate, wherein the one or more gas return orifices are in fluid communication with a vacuum source, therein generally defining an exhaust path for the cushion of gas;
a seal disposed in the annulus region of the clamping plate, wherein the seal is configured to generally prevent a leakage of the cushion of gas from the central region to an environment external to the annulus region; and
one or more electrodes associated with at least the central region, wherein the one or more electrodes are electrically connected to a first voltage potential.
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Accused Products
Abstract
An electrostatic clamp is provided having a clamping plate, wherein the clamping plate has a central region and an annulus region. A plurality of gas supply orifices are defined in the central region of the clamping plate, wherein the plurality of gas supply orifices are in fluid communication with a pressurized gas supply, and wherein the pressurized gas supply is configured to provide a cushion of gas between the clamping surface and the workpiece in the central region of the clamping plate via the plurality of gas supply orifices. One or more gas return orifices defined in one or more of the central region and annulus region of the clamping plate, wherein the one or more gas return orifices are in fluid communication with a vacuum source, therein generally defining an exhaust path for the cushion of gas. A seal is disposed in the annulus region of the clamping plate, wherein the seal is configured to generally prevent a leakage of the cushion of gas from the central region to an environment external to the annulus region. One or more electrodes are further electrically connected to a first voltage potential to provide a first clamping force.
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Citations
20 Claims
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1. An electrostatic clamp for selectively maintaining a position of a workpiece, the electrostatic clamp comprising:
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a clamping plate having a clamping surface associated with the workpiece, wherein the clamping plate has a central region and an annulus region defined therein, and wherein the annulus region is generally disposed about a periphery of the central region; a plurality of gas supply orifices defined in the central region of the clamping plate, wherein the plurality of gas supply orifices are in fluid communication with a pressurized gas supply, and wherein the pressurized gas supply is configured to provide a cushion of gas between the clamping surface and the workpiece in the central region of the clamping plate via the plurality of gas supply orifices; one or more gas return orifices defined in one or more of the central region and annulus region of the clamping plate, wherein the one or more gas return orifices are in fluid communication with a vacuum source, therein generally defining an exhaust path for the cushion of gas; a seal disposed in the annulus region of the clamping plate, wherein the seal is configured to generally prevent a leakage of the cushion of gas from the central region to an environment external to the annulus region; and one or more electrodes associated with at least the central region, wherein the one or more electrodes are electrically connected to a first voltage potential. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. An electrostatic clamp for selectively maintaining a position of a workpiece, the electrostatic clamp comprising:
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a clamping plate having a clamping surface associated with the workpiece, wherein the clamping plate has a central region and an annulus region defined therein, and wherein the annulus region is generally disposed about a periphery of the central region, and wherein the central region of the clamping plate comprises a porous plate having a predetermined porosity associated therewith, wherein the predetermined porosity is defined by a ratio of a volume of voids to a volume of bulk material of the porous plate and generally defines a plurality of gas supply orifices in the central region of the clamping plate, wherein the plurality of gas supply orifices are in fluid communication with a pressurized gas supply, and wherein the pressurized gas supply is configured to provide a cushion of gas between the clamping surface and the workpiece in the central region of the clamping plate via the plurality of gas supply orifices; one or more gas return orifices defined in one or more of the central region and annulus region of the clamping plate, wherein the one or more gas return orifices are in fluid communication with a vacuum source, therein generally defining an exhaust path for the cushion of gas; a seal disposed in the annulus region of the clamping plate, wherein the seal is configured to generally prevent a leakage of the cushion of gas from the central region to an environment external to the annulus region; and one or more electrodes associated with at least the central region, wherein the one or more electrodes are electrically connected to a first voltage potential.
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19. A method for clamping a workpiece, the method comprising:
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providing a clamping plate, wherein the clamping plate comprises a central region and an annulus region defined therein, wherein a first electrode is associated with at least the central region; placing the workpiece over the clamping plate, wherein a peripheral region of the workpiece resides over the annulus region of the clamping plate; providing a cushioning gas via a plurality of gas supply orifices defined in the central region of the clamping plate at a first gas pressure, wherein the cushioning gas generally repels the workpiece from the clamping plate with a first repelling force and provides a generally frictionless interface between the workpiece and at least the central region of the clamping plate; applying a first voltage potential to the first electrode, therein generally attracting the workpiece to the clamping plate with a first attractive force; and controlling the first gas pressure and first voltage potential, wherein the first repelling force and first attractive force are generally equalized. - View Dependent Claims (20)
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Specification