Polarization-modulating element, illumination optical apparatus, exposure apparatus, and exposure method
First Claim
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1. An illumination optical apparatus which illuminates an object having a pattern with illumination light, the illumination optical apparatus comprising:
- a polarization-modulating element made of an optical material having optical activity, which is arranged in an optical path of the illumination light and which changes a polarization state of the illumination light incident on the polarization-modulating element into a predetermined polarization state based on the optical activity of the optical material, the polarization-modulating element having a circumferentially varying thickness profile;
an annular ratio changing optical system, arranged in the optical path of the illumination light, that changes an annular ratio of a light intensity distribution formed on an illumination pupil of the illumination optical apparatus; and
an optical integrator arranged in the optical path of the illumination light so that a rear focal plane of the optical integrator is substantially coincident with the illumination pupil,wherein the polarization-modulating element is arranged between the annular ratio changing optical system and the optical integrator, andwherein the circumferentially varying thickness profile is formed to change a linearly polarized state of the illumination light having a polarization direction substantially along a single direction into an azimuthal polarized state having a polarization direction substantially along a circumferential direction on the illumination pupil.
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Abstract
There is disclosed a polarization-modulating element for modulating a polarization state of incident light into a predetermined polarization state, the polarization-modulating element being made of an optical material with optical activity and having a circumferentially varying thickness profile.
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Citations
17 Claims
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1. An illumination optical apparatus which illuminates an object having a pattern with illumination light, the illumination optical apparatus comprising:
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a polarization-modulating element made of an optical material having optical activity, which is arranged in an optical path of the illumination light and which changes a polarization state of the illumination light incident on the polarization-modulating element into a predetermined polarization state based on the optical activity of the optical material, the polarization-modulating element having a circumferentially varying thickness profile; an annular ratio changing optical system, arranged in the optical path of the illumination light, that changes an annular ratio of a light intensity distribution formed on an illumination pupil of the illumination optical apparatus; and an optical integrator arranged in the optical path of the illumination light so that a rear focal plane of the optical integrator is substantially coincident with the illumination pupil, wherein the polarization-modulating element is arranged between the annular ratio changing optical system and the optical integrator, and wherein the circumferentially varying thickness profile is formed to change a linearly polarized state of the illumination light having a polarization direction substantially along a single direction into an azimuthal polarized state having a polarization direction substantially along a circumferential direction on the illumination pupil. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification