Lithographic apparatus and device manufacturing method
First Claim
1. A lithographic apparatus, comprising:
- a displacement system that causes relative displacement between a lens array and a 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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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.
23 Citations
21 Claims
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1. A lithographic apparatus, comprising:
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a displacement system that causes relative displacement between a lens array and a 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, 9, 10, 11)
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12. A lithographic device manufacturing method, comprising:
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(a) displacing a lens array with respect to a substrate toward and away from each other; (b) detecting a particle on the substrate that approaches the lens array as a result of step (a); and (c) increasing the spacing between the lens array and the substrate in response to step (b), 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 (13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification