Internal split faraday shield for a plasma source
First Claim
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1. A method of operating a plasma source for a focused beam system, the plasma source including a plasma chamber comprising:
- providing radio frequency energy into the plasma chamber from at least one conductive coil to maintain a plasma in the plasma chamber;
providing a conductive shield positioned within the plasma chamber such that no portion of the conductive shield extends into a second chamber containing a workpiece to reduce capacitive coupling between the source of the radio frequency and the plasma;
maintaining the plasma and the conductive shield at electrical potentials different from ground potential;
extracting charged particles from the plasma chamber;
focusing the charged particles into a beam and directing the beam onto or near the workpiece outside of the plasma chamber; and
further comprising providing a biasing electrode in contact with the conductive shield in which the biasing electrode biases the conductive shield potential to a potential of greater than 1000 V.
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Abstract
An inductively coupled plasma source for a focused charged particle beam system includes a conductive shield within the plasma chamber in order to reduce capacitative coupling to the plasma. The internal conductive shield is maintained at substantially the same potential as the plasma source by a biasing electrode or by the plasma. The internal shield allows for a wider variety of cooling methods on the exterior of the plasma chamber.
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Citations
17 Claims
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1. A method of operating a plasma source for a focused beam system, the plasma source including a plasma chamber comprising:
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providing radio frequency energy into the plasma chamber from at least one conductive coil to maintain a plasma in the plasma chamber; providing a conductive shield positioned within the plasma chamber such that no portion of the conductive shield extends into a second chamber containing a workpiece to reduce capacitive coupling between the source of the radio frequency and the plasma; maintaining the plasma and the conductive shield at electrical potentials different from ground potential; extracting charged particles from the plasma chamber; focusing the charged particles into a beam and directing the beam onto or near the workpiece outside of the plasma chamber; and further comprising providing a biasing electrode in contact with the conductive shield in which the biasing electrode biases the conductive shield potential to a potential of greater than 1000 V. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of operating a plasma source for a focused beam system, the plasma source including a plasma chamber comprising:
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providing radio frequency energy into the plasma chamber from at least one conductive coil to maintain a plasma in the plasma chamber; providing a conductive shield positioned within the plasma chamber such that no portion of the conductive shield extends into a second chamber containing a workpiece to reduce capacitive coupling between the source of the radio frequency and the plasma; maintaining the plasma and the conductive shield at electrical potentials different from ground potential; extracting charged particles from the plasma chamber; focusing the charged particles into a beam and directing the beam onto or near the workpiece outside of the plasma chamber; and further comprising providing a biasing electrode in contact with the conductive shield in which the biasing electrode maintains the conductive shield at a voltage having a magnitude greater than 1000 V.
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Specification