US20030174408A1
Expired / Lapsed
US
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Refractive projection objective for immersion lithography
Assignee: Carl Zeiss SMT GmbH
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Filing: 2003-03-06
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Granted: —
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Expires: 2023-03-06
Abstract
Abstract A purely refractive projection objective suitable for immersion micro-lithography is designed as a single-waist system with five lens groups, in the case of which a first lens group with a negative refracting power, a second lens group with a positive refracting power, a third lens group with a negative refracting power, a fourth lens group with a positive refracting power and a fifth lens group with a positive refracting power are provided. The system aperture is in the region of maximum beam diameter between the fourth and the fifth lens group. Embodiments of projection objectives according to the invention achieve a very high numerical aperture of NA>1 in conjunction with a large image field, and are distinguished by a good optical correction state and moderate overall size. Pattern widths substantially below 100 nm can be resolved when immersion fluids are used between the projection objective and substrate in the case of operating wavelengths below 200 nm.
Inventors
- 👤 Hans-Juergen Rostalski
- 👤 Wilhelm Ulrich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:42
CPC Classifications
G; G02; G02B; G02B13/00; G02B13/24; G02B13/14; G02B13/143; G02B9/00; G02B9/60; G03; G03F; G03F7/00; G03F7/20; G03F7/70; G03F7/70216; G03F7/70241; G03F7/70341
Claims Analysis
Total Claims: 42
Claim 1
Independent Claim
141 words
1 . Refractive projection objective for projecting a pattern arranged in an object plane of the projection objective into an image plane of the projection objective with the aid of an immersion medium which is arranged between a last optical element of the projection objective and the image plane, comprising: a first lens group, following the image plane, with a negative refracting power; a second lens group, following the first lens group, with a positive refracting power; a third lens group, following the second lens group, with a negative refracting power; a fourth lens group, following the third lens group, with a positive refracting power; a fifth lens group, following the fourth lens group, with a positive refracting power; and a system aperture which is arranged in the region of maximum beam diameter between the fourth and the fifth lens group.
Claim 2
Dependent Claim
141 words
1 . Refractive projection objective for projecting a pattern arranged in an object plane of the projection objective into an image plane of the projection objective with the aid of an immersion medium which is arranged between a last optical element of the projection objective and the image plane, comprising: a first lens group, following the image plane, with a negative refracting power; a second lens group, following the first lens group, with a positive refracting power; a third lens group, following the second lens group, with a negative refracting power; a fourth lens group, following the third lens group, with a positive refracting power; a fifth lens group, following the fourth lens group, with a positive refracting power; and a system aperture which is arranged in the region of maximum beam diameter between the fourth and the fifth lens group.
Claim 3
Dependent Claim
28 words
2 . Projection objective according to claim 1 , wherein the system aperture lies between a plane of maximum beam diameter near the image and the image plane.
Claim 4
Dependent Claim
15 words
3 . Projection objective according to claim 1 having an image-side numerical aperture of NA≧0.9.
Claim 5
Dependent Claim
17 words
4 . Projection objective according to claim 3 having an image-side numerical aperture of at least NA=1.0.
Claim 6
Dependent Claim
30 words
5 . Projection objective according to claim 1 , wherein the projection objective is adapted to an immersion medium which has a refractive index of n>1.3 at an operating wavelength.
Claim 7
Dependent Claim
27 words
6 . Projection objective according to claim 1 , wherein the projection objective has an image-side working distance of between approximately 10 μm and approximately 200 μm.
Claim 8
Dependent Claim
37 words
7 . Projection objective according to claim 1 , wherein a ratio between the focal length of the fourth lens group and the focal length of the fifth lens group is between approximately 0.9 and approximately 1.1.
Claim 9
Dependent Claim
36 words
8 . Projection objective according to claim 1 , wherein a ratio of the magnitudes of the focal lengths of the first lens group and the fifth lens group is between approximately 0.7 and approximately 1.3.
Claim 10
Dependent Claim
33 words
9 . Projection objective according to claim 1 , wherein a ratio between an overall length of the projection objective and the focal length of the fifth lens group is greater than five.
Claim 11
Dependent Claim
20 words
10 . Projection objective according to claim 1 , wherein the first lens group includes at least one aspheric surface.
Claim 12
Dependent Claim
22 words
11 . Projection objective according to claim 1 , wherein at least one aspheric surface is provided in the third lens group.
Claim 13
Dependent Claim
18 words
12 . Projection objective according to claim 1 , wherein not more than nine aspheric surfaces are provided.
Claim 14
Dependent Claim
36 words
13 . Projection objective according to claim 1 , wherein at least one meniscus lens, convex relative to the object plane, with a negative refracting power is arranged in a near zone of the object plane.
Claim 15
Dependent Claim
25 words
14 . Projection objective according to claim 1 , wherein the second lens group has at least four consecutive lenses with a positive refracting power.
Claim 16
Dependent Claim
68 words
15 . Projection objective according to claim 1 , wherein the second lens group has at least one of at least one meniscus lens concave relative to the object plane, with a positive refracting power on an entry side facing the object plane and at least one meniscus lens convex relative to the object plane, with a positive refracting power on the exit side facing the image plane.
Claim 17
Dependent Claim
55 words
16 . Projection objective according to claim 1 , wherein the second lens group in this sequence has at least one meniscus lens, concave relative to the object plane, with a positive refracting power, a biconvex positive lens and at least one meniscus lens, concave relative to the image plane, with a positive refracting power.
Claim 18
Dependent Claim
22 words
17 . Projection objective according to claim 1 , wherein the third lens group has only lenses with a negative refracting power.
Claim 19
Dependent Claim
32 words
18 . Projection objective according to claim 1 , wherein, with reference to a plane of symmetry lying inside the third lens group, the third lens group is of substantially symmetrical construction.
Claim 20
Dependent Claim
38 words
19 . Projection objective according to claim 1 , wherein two oppositely curved, concave surfaces directly opposed to one another in the third lens group are surrounded by two concave surfaces which are concave relative to one another.
Claim 21
Dependent Claim
53 words
20 . Projection objective according to claim 1 , wherein an exit region, facing the third lens group, of the second lens group, and an entry region, following the third lens group, of the fourth lens group are constructed substantially symmetrically relative to a plane of symmetry lying inside the third lens group.
Claim 22
Dependent Claim
39 words
21 . Projection objective according to claim 1 , wherein the fourth lens group has at least one doublet with a biconvex positive lens and a downstream negative meniscus lens with lens surfaces which are concave towards the object.
Claim 23
Dependent Claim
36 words
22 . Projection objective according to claim 1 , wherein in an object-side entry region the fourth lens group has at least one meniscus lens, concave relative to the object plane, with a positive refracting power.
Claim 24
Dependent Claim
34 words
23 . Projection objective according to claim 1 , wherein the sine of the maximum incidence angle of the radiation impinging on the optical surfaces is less than 90% of the image-side numerical aperture.
Claim 25
Dependent Claim
34 words
24 . Projection objective according to claim 23 , wherein the sine of the maximum incidence angle of the radiation impinging on the optical surfaces is less than 85% of the image-side numerical aperture.
Claim 26
Dependent Claim
22 words
25 . Projection objective according to claim 1 , wherein the fifth lens group has exclusively lenses with a positive refracting power.
Claim 27
Dependent Claim
20 words
26 . Projection objective according to claim 1 , wherein the fifth lens group has at least four positive lenses.
Claim 28
Dependent Claim
32 words
27 . Projection objective according to claim 1 , wherein the fifth lens group has at least one meniscus lens with a positive refracting power and lens surfaces concave towards the image.
Claim 29
Dependent Claim
34 words
28 . Projection objective according to claim 1 , wherein, as last optical element, the fifth lens group has a plano-convex lens which preferably has an entry surface and a substantially flat exit surface.
Claim 30
Dependent Claim
19 words
29 . Projection objective according to claim 28 , wherein the plano-convex lens is constructed in a non-hemispherical fashion.
Claim 31
Dependent Claim
18 words
30 . Projection objective according to claim 1 , wherein all the lenses consist of the same material.
Claim 32
Dependent Claim
29 words
31 . Projection objective according to claim 1 which is a single-waist system with a belly near the object, a belly remote from the object and a waist therebetween.
Claim 33
Dependent Claim
34 words
32 . Projection objective according to claim 1 , wherein the image field diameter is at least one of more than 10 mm and more than 1.0% of the overall length of the objective.
Claim 34
Dependent Claim
25 words
33 . Projection objective according to claim 1 , wherein the light conductance is more than approximately 1% of the overall length of the objective.
Claim 35
Dependent Claim
30 words
34 . Projection objective according to claim 1 , wherein at least four times as many lenses are arranged upstream of the system aperture than downstream of the system aperture.
Claim 36
Dependent Claim
32 words
35 . Projection objective according to claim 1 , wherein at least five lenses with a positive refracting power are arranged between a waist of the projection objective and the system aperture.
Claim 37
Dependent Claim
30 words
36 . Projection objective according to claim 31 , wherein a distance between the waist and the system aperture is at least 26% of the overall length of the objective.
Claim 38
Dependent Claim
34 words
37 . Projection objective according to claim 1 , wherein a maximum rim ray height is at least twice as large as the rim ray height at the location of narrowest constriction of rays.
Claim 39
Dependent Claim
148 words
38 . Projection exposure machine for microlithography, having a refractive projection objective for projecting a pattern arranged in an object plane of the projection objective into an image plane of the projection objective with the aid of an immersion medium which is arranged between a last optical element of the projection objective and the image plane, comprising: a first lens group, following the image plane, with a negative refracting power; a second lens group, following the first lens group, with a positive refracting power; a third lens group, following the second lens group, with a negative refracting power; a fourth lens group, following the third lens group, with a positive refracting power; a fifth lens group, following the fourth lens group, with a positive refracting power; and a system aperture which is arranged in the region of maximum beam diameter between the fourth and the fifth lens group.
Claim 40
Dependent Claim
148 words
38 . Projection exposure machine for microlithography, having a refractive projection objective for projecting a pattern arranged in an object plane of the projection objective into an image plane of the projection objective with the aid of an immersion medium which is arranged between a last optical element of the projection objective and the image plane, comprising: a first lens group, following the image plane, with a negative refracting power; a second lens group, following the first lens group, with a positive refracting power; a third lens group, following the second lens group, with a negative refracting power; a fourth lens group, following the third lens group, with a positive refracting power; a fifth lens group, following the fourth lens group, with a positive refracting power; and a system aperture which is arranged in the region of maximum beam diameter between the fourth and the fifth lens group.
Claim 41
Dependent Claim
174 words
39 . Method for producing semiconductor components and other finely structured structural elements comprising: providing a mask with a prescribed pattern; illuminating the mask with ultraviolet light of a prescribed wavelength; and projecting an image of the pattern onto a photosensitive substrate, arranged in the region of the image plane of a projection objective, with the aid of a projection objective having: a first lens group, following the image plane, with a negative refracting power; a second lens group, following the first lens group, with a positive refracting power; a third lens group, following the second lens group, with a negative refracting power; a fourth lens group, following the third lens group, with a positive refracting power; a fifth lens group, following the fourth lens group, with a positive refracting power; and a system aperture which is arranged in the region of maximum beam diameter between the fourth and the fifth lens group; an immersion medium arranged between a last optical surface of the projection objective and the substrate being trans-illuminated during the projection.
Claim 42
Dependent Claim
174 words
39 . Method for producing semiconductor components and other finely structured structural elements comprising: providing a mask with a prescribed pattern; illuminating the mask with ultraviolet light of a prescribed wavelength; and projecting an image of the pattern onto a photosensitive substrate, arranged in the region of the image plane of a projection objective, with the aid of a projection objective having: a first lens group, following the image plane, with a negative refracting power; a second lens group, following the first lens group, with a positive refracting power; a third lens group, following the second lens group, with a negative refracting power; a fourth lens group, following the third lens group, with a positive refracting power; a fifth lens group, following the fourth lens group, with a positive refracting power; and a system aperture which is arranged in the region of maximum beam diameter between the fourth and the fifth lens group; an immersion medium arranged between a last optical surface of the projection objective and the substrate being trans-illuminated during the projection.
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