EP0467445A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Apparatus for projecting a mask pattern on a substrate
Assignee: ASML Netherlands BV
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Filing: 1991-07-05
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Granted: —
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Expires: 2011-07-05
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 mask alignment mark (M 1 , M 2 ) with respect to a substrate alignment mark (P 1 , P 2 ). Means (WE 1 , WE 2 ) preventing phase differences due to reflections at the mask plate (MA) from occurring within the alignment beam portions received by a detection system (13, 13') are arranged in the path of selected alignment beam portions (bi, bi').
Inventors
- 👤 Marinus Aart Van Den Brink
- 👤 Henk Frederik Dirk Linders
- 👤 Stefan Wittekoek
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 02:50
CPC Classifications
G; G03; G03F; G03F9/00; G03F9/70; G03F9/7049; G03F9/7003
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
167 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 the mask with respect to the substrate by means of a substrate alignment mark and 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 selected alignment beam portions which have been in interaction with a first alignment mark and a second alignment mark on which the first alignment mark is imaged, the output signal of the detection system being a measure of the mutual position of the alignment marks, characterized in that means preventing phase differences due to reflections at a mask plate from occurring within the selected alignment beam portions received by the detection system are arranged in the radiation path of the selected alignment beam portions.
Claim 2
Independent Claim
167 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 the mask with respect to the substrate by means of a substrate alignment mark and 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 selected alignment beam portions which have been in interaction with a first alignment mark and a second alignment mark on which the first alignment mark is imaged, the output signal of the detection system being a measure of the mutual position of the alignment marks, characterized in that means preventing phase differences due to reflections at a mask plate from occurring within the selected alignment beam portions received by the detection system are arranged in the radiation path of the selected alignment beam portions.
Claim 3
Dependent Claim
29 words
An apparatus as claimed in Claim 1, characterized in that a part of the mask plate surface located opposite the mask alignment mark is anti-reflective to the alignment radiation.
Claim 4
Dependent Claim
42 words
A mask plate for use in the apparatus as claimed in Claim 2 and having a mask alignment mark, characterized in that at least a part of the plate surface located opposite the mask alignment mark is anti-reflective to the alignment radiation.
Claim 5
Dependent Claim
64 words
An apparatus as claimed in Claim 1, characterized in that a radiation deflection element is arranged in the vicinity of a mask alignment mark for directing the axis of symmetry of selected alignment beam portions principally perpendicularly to the plane of the mask plate, said radiation deflection element being considerably smaller than the cross-section of the projection beam in the plane of said plate.
Claim 6
Dependent Claim
30 words
An apparatus as claimed in Claim 4, characterized in that the radiation deflection element is constituted by a wedge-shaped body of a material which is transparent to the alignment beam.
Claim 7
Dependent Claim
80 words
An apparatus as claimed in Claim 4, which in addition to said device for aligning a first mask alignment mark with respect to a substrate alignment mark comprises a second device for aligning a second mask alignment mark with respect to a substrate alignment mark by means of a second alignment beam, characterized in that a second radiation deflection element is arranged in the path of the second alignment beam and in the vicinity of a second mask alignment mark.
Claim 8
Dependent Claim
74 words
An apparatus as claimed in Claim 1, 2, 4, 5 or 6, characterized in that a refractive correction element is arranged in the path of an alignment beam and in the projection lens system, which element is considerably smaller than the cross-section of the projection lens system in the plane of said element, and which only directs and focuses the selected alignment beam portions from the first alignment mark on the second alignment mark.
Claim 9
Dependent Claim
16 words
An apparatus as claimed in Claim 7, characterized in that the correction element is a lens.
Claim 10
Dependent Claim
26 words
An apparatus as claimed in Claim 7 or 8, characterized in that the correction element is arranged in the Fourier plane of the projection lens system.
Claim 11
Dependent Claim
58 words
An apparatus as claimed in Claim 1, 4, 5, 6, 7, 8 or 9, 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 the radiation deflection element is arranged in the path of the alignment radiation coming from the substrate alignment mark.
Claim 12
Dependent Claim
58 words
An apparatus as claimed in Claim 1, 4, 5, 6, 7, 8 or 9, 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 the radiation deflection element is arranged in the path of the alignment radiation coming from the mask alignment mark.
Claim 13
Dependent Claim
62 words
An apparatus as claimed in Claim 1, 4, 5, 6, 7, 8 or 9, characterized in that the second alignment mark is a reference alignment mark which is located outside the substrate and outside the mask, and in that both a substrate alignment mark and a mask alignment mark constitute first alignment marks which are each imaged on the reference alignment mark.
Claim 14
Dependent Claim
79 words
An apparatus as claimed in Claim 1, 4, 5, 6, 7, 8 or 9, characterized in that the radiation source of the alignment device supplies two radiation beams which form an interference pattern in the plane of a substrate alignment mark and in the plane of a mask alignment mark, in that the first alignment mark is constituted by the interference pattern and in that both the substrate alignment mark and the mask alignment mark are second alignment marks.
Claim 15
Independent Claim
33 words
An apparatus as claimed in Claims 1-13, characterized in that a substrate alignment mark is constituted by a phase diffraction grating and a mask alignment mark is constituted by an amplitude diffraction grating.
Claim 16
Independent Claim
53 words
An apparatus as claimed in Claims 1-14, characterized in that means controlled by periodical signals are arranged in the radiation path of an alignment beam for periodically displacing with respect to each other a second alignment mark and the image on said mark of a first alignment mark observed by the detection system.
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US4865455A
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US4771180A
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EP0237109A1
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