Lithographic apparatus and device manufacturing method
First Claim
1. A lithographic apparatus, comprising:
- an illumination system that supplies a beam of radiation;
a patterning system that patterns the beam;
a projection system that projects the patterned beam onto a target portion of a substrate, the projection system comprising a lens array spaced from the substrate, such that each lens in the lens array focuses a respective part of the patterned beam onto the substrate;
a displacement system that causes relative displacement between the lens array and the substrate to increase a spacing between the lens array and the substrate;
a particle detector that detects particles on the substrate that are approaching the lens array as a result of relative displacement between the lens array and the substrate; and
a free working distance control system that increases the spacing between the lens array and the substrate in response to detection of a particle by the particle detector, such that the lens array is moved away from the substrate using the displacement system as relative displacement causes the detected particle to pass below the lens array.
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Accused Products
Abstract
A lithographic apparatus and method in which an illumination system supplies a projection beam, a patterning system imparts to the beam a pattern in its cross section, and a projection system projects the patterned beam onto a target portion of a substrate. The projection system comprises an array of lenses spaced from the substrate such that each lens in the array focuses part of the patterned beam onto the substrate. A displacement system causes displacement between the lens array and the substrate. A particle detector detects particles on the substrate which are approaching the lens array. A free working distance control system increases the spacing between the lens array and the substrate in response to detection of a particle. The lens array is moved away from the substrate as the detected particle passes the lens array. Thus damage to the lens array can be avoided.
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Citations
15 Claims
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1. A lithographic apparatus, comprising:
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an illumination system that supplies a beam of radiation; a patterning system that patterns the beam; a projection system that projects the patterned beam onto a target portion of a substrate, the projection system comprising a lens array spaced from the substrate, such that each lens in the lens array focuses a respective part of the patterned beam onto the substrate; a displacement system that causes relative displacement between the lens array and the substrate to increase a spacing between the lens array and the substrate; a particle detector that detects particles on the substrate that are approaching the lens array as a result of relative displacement between the lens array and the substrate; and a free working distance control system that increases the spacing between the lens array and the substrate in response to detection of a particle by the particle detector, such that the lens array is moved away from the substrate using the displacement system as relative displacement causes the detected particle to pass below the lens array. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A lithographic device manufacturing method, comprising:
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(a) patterning a beam of radiation; (b) projecting the patterned beam onto a target portion of a substrate through a lens array that is spaced from the substrate, such that each lens in the lens array focuses a respective part of the patterned beam onto the substrate; (c) displacing the lens array with respect to the substrate toward and away from each other; (d) detecting particles on the substrate that approach the lens array as a result of step (c); and (e) increasing the spacing between the lens array and the substrate in response to step (d), such that the lens array is moved away from the substrate until relative displacement causes the detected particle to pass the lens array. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification