Illumination system coherence remover with a series of partially reflective surfaces
First Claim
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1. A coherence remover, comprising:
- a first partially reflective surface;
a second partially reflective surface separated from the first partially reflective surface by a fixed distance along a normal axis of the first and second partially reflective surfaces;
a polarizing beam splitter configured to receive an input beam and to pass the input beam having a first polarization such that the input beam is incident on the first and second partially reflective surfaces,wherein each of the first and second partially reflective surfaces is configured to reflect a respective portion of the input beam to produce one or more respective intermediate beams, and to pass the non-reflected portion of the input beam;
a substantially fully reflective mirror configured to reflect a portion of the input beam to produce additional intermediate beams,wherein the one or more respective intermediate beams and the additional intermediate beams collectively form an output beam that has a reduced coherence compared to the input beam; and
a quarter wave plate configured to alter a polarization state of the output beam,wherein the polarizing beam splitter is configured to receive the altered output beam having a second polarization and to reflect the altered output beam.
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Abstract
A coherence remover includes a first partially reflective surface and a second partially reflective surface. The coherence remover is configured to receive an input beam. Each of the first and second reflective surfaces is configured to reflect a respective portion of the input beam to produce respective one or more intermediate beams. The intermediate beams collectively form an output beam that has a reduced coherence compared to the input beam.
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Citations
10 Claims
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1. A coherence remover, comprising:
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a first partially reflective surface; a second partially reflective surface separated from the first partially reflective surface by a fixed distance along a normal axis of the first and second partially reflective surfaces; a polarizing beam splitter configured to receive an input beam and to pass the input beam having a first polarization such that the input beam is incident on the first and second partially reflective surfaces, wherein each of the first and second partially reflective surfaces is configured to reflect a respective portion of the input beam to produce one or more respective intermediate beams, and to pass the non-reflected portion of the input beam; a substantially fully reflective mirror configured to reflect a portion of the input beam to produce additional intermediate beams, wherein the one or more respective intermediate beams and the additional intermediate beams collectively form an output beam that has a reduced coherence compared to the input beam; and a quarter wave plate configured to alter a polarization state of the output beam, wherein the polarizing beam splitter is configured to receive the altered output beam having a second polarization and to reflect the altered output beam. - View Dependent Claims (2, 3, 4)
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5. A lithographic apparatus, comprising:
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a coherence remover, comprising; a first partially reflective surface; a second partially reflective surface separated from the first partially reflective surface by a fixed distance along a normal axis of the first and second partially reflective surfaces; a polarizing beam splitter configured to receive an input beam and to pass the input beam having a first polarization such that the input beam is incident on the first and second partially reflective surfaces, wherein each of the first and second partially reflective surfaces is configured to reflect a respective portion of the input beam to produce one or more respective intermediate beams, and to pass the non-reflected portion of the input beam; a substantially fully reflective mirror configured to reflect a portion of the input beam to produce additional intermediate beams, wherein the one or more respective intermediate beams and the additional intermediate beams collectively form an output beam that has a reduced coherence compared to the input beam; and a quarter wave plate configured to alter a polarization state of the output beam, wherein the polarizing beam splitter is configured to receive the altered output beam having a second polarization and to reflect the altered output beam; and a homogenizer configured to convert the output beam into a plurality of beams. - View Dependent Claims (6, 7, 8, 9, 10)
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Specification