Patent US5100237A successfully refreshed from Google Patents.
US5100237A
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Apparatus for projecting a mask pattern on a substrate
Assignee: ASML Netherlands BV
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Filing: 1990-05-25
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Granted: 1992-03-31
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Expires: 2010-05-25
Abstract
Abstract An apparatus for projecting a mask pattern (MA) on a substrate (W) by means of a projection lens system (PL) is described, which apparatus comprises a device for aligning a substrate alignment mark (P 1 ; P 2 ) with respect to a mask alignment mark (M 1 ; M 2 ), the projection lens system (PL) forming part of the alignment device. A correction element (25) is arranged in this system (PL) to compensate for the fact that this system (PL) is not optimized for the wavelength of the alignment beam (b).
Inventors
- 👤 Stefan Wittekoek
- 👤 Marinus A. Van Den Brink
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:56
CPC Classifications
G; G03; G03F; G03F9/00; G03F9/70; G03F9/7049; G01; G01B; G01B9/00; G01B9/02
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
200 words
An apparatus for projecting a mask pattern on a substrate, which apparatus successively comprises an illumination system for supplying a projection beam, a mask holder, a projection lens system and a substrate holder and which further comprises a device for aligning a substrate alignment mark with respect to a mask alignment mark, said device comprising a radiation source supplying an alignment beam, the projection lens system and a radiation-sensitive detection system in the path of alignment beam portions which have been in interaction with the substrate alignment mark and the mask alignment mark, the output signals of the detection system being a measure of the mutual position of the alignment marks, characterized in that a refractive correction element is arranged in the path of the alignment beam and in the projection lens system, the dimension of said correction element being smaller than the diameter of the projection lens system in the plane of said element such that the quality of the image of the mask on the substrate is maintained, said correction element deflecting and focusing only sub-beams of the alignment beam which are deflected in the first diffraction orders by a first alignment mark onto a second alignment mark.
Claim 2
Independent Claim
200 words
An apparatus for projecting a mask pattern on a substrate, which apparatus successively comprises an illumination system for supplying a projection beam, a mask holder, a projection lens system and a substrate holder and which further comprises a device for aligning a substrate alignment mark with respect to a mask alignment mark, said device comprising a radiation source supplying an alignment beam, the projection lens system and a radiation-sensitive detection system in the path of alignment beam portions which have been in interaction with the substrate alignment mark and the mask alignment mark, the output signals of the detection system being a measure of the mutual position of the alignment marks, characterized in that a refractive correction element is arranged in the path of the alignment beam and in the projection lens system, the dimension of said correction element being smaller than the diameter of the projection lens system in the plane of said element such that the quality of the image of the mask on the substrate is maintained, said correction element deflecting and focusing only sub-beams of the alignment beam which are deflected in the first diffraction orders by a first alignment mark onto a second alignment mark.
Claim 3
Dependent Claim
25 words
An apparatus as claimed in claim 1, characterized in that the refractive correction element is arranged in the Fourier plane of the projection lens system.
Claim 4
Dependent Claim
17 words
An apparatus as claimed in claim 2, characterized in that the refractive correction element is a lens.
Claim 5
Dependent Claim
56 words
An apparatus as claimed in claim 1, 2 or 3, characterized in that an extra lens for correcting the magnification with which the first alignment mark is imaged on the second alignment mark is arranged in the radiation path of the alignment beam between the first and second alignment marks and outside the projection lens system.
Claim 6
Dependent Claim
28 words
An apparatus as claimed in claim 4, characterized in that the extra lens is arranged proximate to the first alignment mark or proximate to the second alignment mark.
Claim 7
Dependent Claim
25 words
An apparatus as claimed in claim 5, characterized in that the extra lens is arranged between the projection lens system and a mask alignment mark.
Claim 8
Dependent Claim
46 words
An apparatus as claimed in claim 1, 2 or 3, characterized in that a diaphragm is arranged in the projection lens system, which diaphragm blocks those portions of the alignment beam coming from the first alignment mark which have diffraction orders which are higher than one.
Claim 9
Dependent Claim
58 words
An apparatus as claimed in claim 7, characterized in that the diaphragm is constituted by a layer which is transparent to the projection beam and the aligment beam, which layer has regions blocking the radiation of the alignment beam at those positions where the portions of the alignment beam with diffraction orders higher than one reach said layer.
Claim 10
Dependent Claim
60 words
An apparatus as claimed in claim 7, characterized in that the diaphragm is constituted by a layer of dichroic material which is transparent to the projection beam and opaque to the alignment beam, which layer has regions which are transparent to the alignment beam at those positions where the first diffraction order portions of the alignment beam reach said layer.
Claim 11
Dependent Claim
56 words
An apparatus as claimed in claim 1, 2 or 3, characterized in that a diaphragm is arranged between the projection lens system and the second alignment mark, which diaphragm is transparent to radiation in the region where the portions of the alignment beam diffracted in the first orders by the first alignment mark reach said diaphragm.
Claim 12
Dependent Claim
53 words
An apparatus as claimed in claim 10, characterized in that a diaphragm system, which only passes the portions of the alignment beam diffracted in the first orders by the first alignment mark and the second alignment mark to the radiation-sensitive detection system, is arranged between the second alignment mark and said detection system.
Claim 13
Independent Claim
40 words
An apparatus as claimed in any one of claims 1, 2 or 3, characterized in that the illumination system supplies a projection beam which has an annular cross-section in the plane of the correction element in the projection lens system.
Claim 14
Independent Claim
85 words
An apparatus as claimed in any one of claims 1, 2 or 3, characterized in that the first alignment mark is a mask alignment mark and the second alignment mark is a substrate alignment mark, and in that a reflector is arranged in the path of alignment sub-beam portions, which are diffracted firstly by the mask alignment mark in the first orders and subsequently by the substrate alignment mark in the first orders, said reflector only reflecting said alignment sub-beam portions towards a detection system.
Claim 15
Independent Claim
59 words
An apparatus as claimed in any one of claims 1, 2 or 3, characterized in that the second alignment mark is formed by a further alignment mark located outside the substrate and in that a mask alignment mark as well as a substrate alignment mark are a first alignment mark, both of which are projected on the further mark.
Claim 16
Independent Claim
77 words
An apparatus as claimed in any one of claims 1, 2 or 3, characterized in that the radiation source of the alignment device supplies two radiation beams forming an interference pattern in the plane of the mask alignment mark and in the plane of the substrate alignment mark, in that the first alignment mark is formed by a part of said interference pattern and in that the second alignment mark is formed by a substrate alignment mark.
Claim 17
Independent Claim
59 words
An apparatus as claimed in any one of claims 1, 2 or 3, characterized in that the first alignment mark is a substrate alignment mark and the second alignment mark is a mask alignment mark, and in that a reflector for reflecting the alignment beam towards the substrate alignment mark is arranged between the correction element and said mark.
Claim 18
Dependent Claim
25 words
An apparatus as claimed in claim 16, characterized in that the correction element is located in the rear focal plane of the projection lens system.
Claim 19
Dependent Claim
77 words
An apparatus as claimed in claim 16, in which a reflector is arranged between a mask table and the projection lens system for reflecting the alignment beam into the projection lens system, characterized in that a diaphragm system, which blocks the portions with diffraction orders of more than one as well as the zero order portion of the alignment beam coming from a substrate alignment mark, is arranged between the projection lens system and the detection system.
Claim 20
Dependent Claim
61 words
An apparatus as claimed in claim 16, characterized in that a holder of the projection lens system has a radiation transparent window through which an alignment beam can enter transversally with respect to the optical axis of said system and in that a reflector for reflecting a entering alignment beam to the substrate table is arranged is the projection lens system.
Claim 21
Dependent Claim
70 words
An apparatus as claimed in claim 16, characterized in that the reflector has a first and second reflecting face for reflecting the first and second alignment beam, respectively, to a substrate table, said faces extending at equally large but opposite angles to the optical axis of the projection lens system and in that a holder of the projection lens system has two radiation-transparent windows situated opposite the said reflecting faces.
Claim 22
Dependent Claim
90 words
An apparatus as claimed in claim 20, characterized in that first and second alignment devices have one common radiation source for supplying two alignment beams which reach one and the same radiation-transparent window in the holder of the projection lens system from different directions, whereafter one of the alignment beams is directly incident on one of the reflecting faces, while the other alignment beam leaves the said holder via a second radiation-transparent window and is indicent on an additional reflector which reflects said alignment beam to the second reflecting face.
Claim 23
Dependent Claim
72 words
An apparatus as claimed in claim 13, comprising a first and a second alignment device, characterized in that the first and the second alignment device have a reflector in common for reflecting beam portions of double diffraction orders (+1,-1) and (-1,+1) of the alignment beams towards associated detection systems, the first and the second number of the diffraction orders being associated with a mask alignment mark and a substrate alignment mark, respectively.
Claim 24
Dependent Claim
65 words
Apparatus as claimed in claim 14, characterized in that the further alignment mark is arranged at the side of a mask remote from the projection lens system, that the mask alignment mark is reflective and that the mask comprises a transparent window in the vicinity of said mark for passing alignment radiation towards the substrate alignment mark and alignment radiation reflected by the latter mark.
Claim 25
Dependent Claim
33 words
Apparatus as claimed in claim 23, characterized in that a Fourier lens system is arranged between the mask and the further alignment mark, a spatial filter being included in the Fourier lens system.
Claim 26
Dependent Claim
39 words
Apparatus as claimed in claim 23, characterized in that in the path of the alignment radiation behind the further alignment mark two detectors are arranged for capturing radiation from the mask alignment mark and the substrate alignment mark respectively.
Claim 27
Dependent Claim
23 words
Apparatus as claimed in claim 25, characterized in that an imaging lens is arranged between the further alignment mark and the two detectors.
Claim 28
Dependent Claim
52 words
Apparatus as claimed in claim 24, characterized in that between the Fourier lens system and the mask a partly transmissive reflector is arranged for reflecting the alignment beam towards the mask and for transmitting alignment radiation reflected from the mask alignment mark and the substrate alignment mark towards the further alignment mark.
Claim 29
Independent Claim
35 words
An apparatus as claimed in any one of claims 1, 2 or 3, characterized in that a substrate and a mask alignment mark has the form of a phase and an amplitude diffraction grating, respectively.
Claim 30
Independent Claim
58 words
An apparatus as claimed in any one of claims 1, 2 or 3, characterized in that means controlled by periodical signals are arranged in the path of an alignment beam for periodically displacing a second alignment mark observed by the detection system and an image on said mark of a first alignment mark with respect to each other.
Claim 31
Dependent Claim
81 words
An apparatus as claimed in claim 13, wherein said device for aligning said mask alignment mark with respect to said substrate alignment mark includes a first device for aligning a first mask alignment mark with respect to said substrate alignment mark as well as a second device for aligning a second alignment mark with respect to said substrate alignment mark by means of a second alignment beam, characterized in that the first and second alignment devices have one common correction element.
Claim 32
Dependent Claim
81 words
An apparatus as claimed in claim 14, wherein said device for aligning said mask alignment mark with respect to said substrate alignment mark includes a first device for aligning a first mask alignment mark with respect to said substrate alignment mark as well as a second device for aligning a second alignment mark with respect to said substrate alignment mark by means of a second alignment beam, characterized in that the first and second alignment devices have one common correction element.
Claim 33
Dependent Claim
81 words
An apparatus as claimed in claim 15, wherein said device for aligning said mask alignment mark with respect to said substrate alignment mark includes a first device for aligning a first mask alignment mark with respect to said substrate alignment mark as well as a second device for aligning a second alignment mark with respect to said substrate alignment mark by means of a second alignment beam, characterized in that the first and second alignment devices have one common correction element.
Claim 34
Dependent Claim
81 words
An apparatus as claimed in claim 16, wherein said device for aligning said mask alignment mark with respect to said substrate alignment mark includes a first device for aligning a first mask alignment mark with respect to said substrate alignment mark as well as a second device for aligning a second alignment mark with respect to said substrate alignment mark by means of a second alignment beam, characterized in that the first and second alignment devices have one common correction element.
Claim 35
Dependent Claim
54 words
An apparatus as claimed in claim 1, wherein said device for aligning a substrate alignment mark with respect to a mask alignment mark includes a first and second alignment device for aligning a substrate alignment mark with respect to a mask alignment mark, said first and second alignment devices having one common correction element.
References Cited (Backward Citations)
US4795244A
Cited
US4778275A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-03-31 | 1995-09-30 | 1996-03-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-03-31 | 1999-09-30 | 2000-03-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-03-31 | 2003-09-30 | 2004-03-31 | $7700.00 | Window Closed / Lapsed |