Optical element and manufacturing method therefor
AssigneeCanon Kabushiki Kaisha
InventorsYasuyuki Unno, Seiji Takeuchi
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Abstract
An optical element and a manufacturing method therefor, an exposure apparatus, and a device manufacturing method that can reduce the effect of intrinsic birefringence under high NA conditions. According to an optical element as one aspect of the present invention, an angle between a [0 0 1] axis of an isometric crystal and an optical axis is less than 10°, and preferably 0°.
Claims7
A projection optical system for projecting a pattern of a mask, said projection optical system comprising plural optical elements, which include an isometric crystal in which an angle between a [0 0 1] axis and an optical axis of the projection optical system is less than 10°,
- wherein the pattern on the mask includes a repetitive pattern and a repetitive direction of the repetitive pattern differs from directions of two axes that are perpendicular to the [0 0 1] axis of the isometric crystal.
A projection optical system for projecting a pattern on a mask, said projection optical system comprising a plural optical elements which includes an isometric crystal in which an angle between a [0 0 1] axis and an optical axis of the projection optical system is less than 10°,
- wherein the pattern on the mask includes a repetitive pattern and a repetitive direction of the repetitive pattern forms one of angles of 0°, 45°, and 90° with respect to a primary direction on a plane that includes the mask, and
- wherein directions of two axes that are perpendicular to the [0 0 1] axis of the isometric crystal differ from the primary direction.
A projection optical system for projecting a pattern of a mask, said projection optical system comprising a plurality of optical elements made of isometric crystals in which an angle between each [0 0 1] axis of the isometric crystals and an optical axis of the projection optical system is less than 10°,
- wherein the pattern on the mask includes a repetitive pattern and a repetitive direction of the repetitive pattern differs from directions of [1 0 0] and [0 1 0] axes that are perpendicular to the [0 0 1] axis of the isometric crystals.
A projection optical system for projecting a pattern on a mask, said projection optical system comprising a plurality of optical elements made of isometric crystals in which an angle between each [0 0 1] axis of the isometric crystals and an optical axis of the projection optical system is less than 10°,
- wherein the pattern on the mask includes a repetitive pattern and a repetitive direction of the repetitive pattern forms one of angles of 0°, 45°, and 90° with respect to a primary direction on a plane that includes the mask, and
- wherein directions of [1 0 0] and [0 1 0] axes that are perpendicular to the [0 0 1] axis of the isometric crystal differ from the repetitive direction.
Dependencies are inferred from the claim text.