Electrode configuration for retaining cooling gas on electrostatic wafer clamp
First Claim
1. Apparatus for electrostatic clamping of a semiconductor wafer, comprising:
- a dielectric element that defines a clamping surface for receiving a semiconductor wafer; and
two or more electrodes electrically isolated from said clamping surface, said electrodes including a first electrode disposed at or near a periphery of said clamping surface and a second electrode disposed inwardly of said first electrode, wherein said first and second electrodes have variable widths that form interdigitated projections along adjacent sides of said first and second electrodes.
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Accused Products
Abstract
Apparatus for electrostatic clamping of a semiconductor wafer includes a dielectric element that defines a clamping surface for receiving the semiconductor wafer and two or more electrodes, including a first electrode disposed at or near a periphery of the clamping surface and a second electrode disposed inwardly of the first electrode. The first and second electrodes have variable widths that form interdigitated projections along adjacent sides of the first and second electrodes. The interdigitated projections limit flexing of the wafer at or near its outer periphery and thereby enhance retention of cooling gas between the semiconductor wafer and the clamping surface.
77 Citations
23 Claims
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1. Apparatus for electrostatic clamping of a semiconductor wafer, comprising:
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a dielectric element that defines a clamping surface for receiving a semiconductor wafer; and
two or more electrodes electrically isolated from said clamping surface, said electrodes including a first electrode disposed at or near a periphery of said clamping surface and a second electrode disposed inwardly of said first electrode, wherein said first and second electrodes have variable widths that form interdigitated projections along adjacent sides of said first and second electrodes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. Apparatus for electrostatic clamping of a workpiece, comprising:
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at least two electrodes comprising strip-like conductors disposed side-by-side and electrically isolated from each other, said strip-like conductors having variable widths that form interdigitated projections along adjacent sides thereof;
a dielectric element disposed on said at least two electrodes, said dielectric element defining a clamping surface for receiving a workpiece; and
a clamping voltage source for applying phase-shifted clamping voltages to said at least two electrodes, wherein the workpiece is electrostatically clamped to said clamping surface. - View Dependent Claims (15, 16, 17, 18, 19)
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20. A method for electrostatic clamping of a workpiece, comprising:
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providing two or more electrodes electrically isolated from a clamping surface for receiving a workpiece, said electrodes including a first electrode disposed at or near a periphery of the clamping surface and a second electrode disposed inwardly of the first electrode, wherein the first and second electrodes have variable widths that form interdigitated projections along adjacent side edges of the first and second electrodes; and
applying phase-shifted clamping voltages to the first and second electrodes, wherein the workpiece is electrostatically clamped to the clamping surface. - View Dependent Claims (21, 22, 23)
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Specification