UV synthetic silica glass optical member and reduction projection exposure apparatus using the same
AssigneeNikon Corporation
InventorsSeishi Fujiwara, Norio Komine, Hiroki Jinbo
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Abstract
This invention provides a synthetic silica glass optical member used together with light having a specific wavelength of 250 nm or less, in which the difference between the maximum value and the minimum value of transmittance [%/cm] per cm in thickness for the light in a predetermined direction within a plane perpendicular to the optical axis is 2.0%/cm or less.
Claims12
A synthetic silica glass optical member used together with light having a specific wavelength of not more than 250 nm, wherein a difference between a maximum value and a minimum value of transmittance per cm (%/cm) in thickness for the light in a predetermined direction within a plane perpendicular to an optical axis is not more than 2.0%/cm.
A reduction projection exposure apparatus comprising:
- an exposure light source for emitting light having a wavelength of not more than 250 nm;
- a photomask having an original image of a pattern;
- an illumination optical system for irradiating said photomask with the light emitted from said light source;
- a projection optical system for projecting the pattern image output from said photomask onto a photosensitive substrate;
- and an alignment system for aligning said photomask and the photosensitive substrate,
- wherein at least a part of lenses of said illumination optical system, lenses of said projection optical system, and said photomask are formed from synthetic silica glass in which a difference between a maximum value and a minimum value of transmittance per cm (%/cm) in thickness for the light in a predetermined direction within a plane perpendicular to an optical axis is not more than 2.0%/cm.
Dependencies are inferred from the claim text.