Refractive projection objective with a waist
AssigneeCarl Zeiss SMT GmbH
InventorKarl-Heinz Schuster
Life of this patent
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Abstract
A refractive projection objective for use in microlithography with lenses made exclusively of one and the same material has an image-side numerical aperture larger than 0.7. A light bundle defined by the image-side numerical aperture and by the image field has within the objective a variable light-bundle diameter smaller than or equal to a maximum light-bundle diameter. In a length interval measured on the optical axis from the system diaphragm towards the object field and at least equaling the maximum light-bundle diameter, the variable light-bundle diameter exceeds 85% of the maximum light-bundle diameter.
Claims32
A refractive projection objective for use in microlithography, comprising a lens arrangement with a system diaphragm, wherein the lens arrangement consists of lenses made exclusively of one and the same material, wherein the objective has an optical axis, an object field, an image field, and an image-side numerical aperture larger than 0.7, wherein a light bundle propagating through the objective is defined by said image field and said image-side numerical aperture and has within the objective a variable light-bundle diameter smaller than or equal to a maximum light-bundle diameter, and wherein in a length interval measured on the optical axis from the system diaphragm towards the object field and at least equaling said maximum light-bundle diameter, said variable light-bundle diameter exceeds 85% of said maximum light-bundle diameter.
A refractive projection objective for use in microlithography, comprising a lens arrangement with a system diaphragm, wherein the lens arrangement consists of lenses made exclusively of one and the same material, wherein each of the lenses has a diameter less than or equal to a maximum lens diameter, wherein the objective has an optical axis, an object field, an image field, and an image-side numerical aperture larger than 0.7, wherein a light bundle propagating through the objective is defined by said image field and said image-side numerical aperture and has within the objective a variable light-bundle diameter, and wherein in a length interval measured on the optical axis from the system diaphragm towards the object field and at least equaling said maximum lens diameter, said variable light-bundle diameter exceeds 85% of said maximum lens diameter.
A refractive projection objective for use in microlithography, comprising a lens arrangement that consists of lenses made exclusively of one and the same material, wherein said objective has a numerical aperture of at least 0.8 and is configured for light of a wavelength shorter than 300 nm within a defined bandwidth of Δλ, and wherein the objective is characterized by a characteristic index KCHL defined as
- KCHL
- =
- CHL
-
- [
- nm
- ]
- Δλ
-
- [
- nm
- ]
- *
- (
- Δ
-
-
- n
- n
- -
- 1
- )
- *
- y
- '
-
- max
-
- [
- nm
- ]
- ,
- wherein
- CHL represents a longitudinal chromatic aberration and Y′ max represents a maximum image field diameter of the objective, and wherein the characteristic index KCHL is less than or equal to 5.5.
A refractive projection objective for use in microlithography, comprising a lens arrangement with a system diaphragm, wherein the lens arrangement is subdivided into three lens groups with a first lens group of positive refractive power forming a first bulge, followed by a second lens group of negative refractive power forming a waist, followed by a third lens group having an elongated configuration taking up 60% of a length measured from the object field to the image field, and wherein the system diaphragm is arranged in the third lens group.
Dependencies are inferred from the claim text.