EXPOSURE METHOD, AND DEVICE MANUFACTURING METHOD
First Claim
1. An exposure method in which a pattern is overlaid and formed in each of a plurality of first areas arranged on an object via a projection optical system, the method comprising:
- performing a suppressing means of an exposure error occurring due to a positional shift of a second area in which a mark corresponding to the plurality of first areas and the first area corresponding to the mark within a plane orthogonal to an optical axis of the projection optical system when the pattern is formed in each of the plurality of first areas arranged on the object.
1 Assignment
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Accused Products
Abstract
A lateral shift ΔXAM of an image of an alignment mark projected on a wafer is obtained for a plurality of linewidth (a to d) which are different to one another and defocus amount (ΔZ), taking into consideration an illumination condition and optical properties of a projection optical system, and the linewidth of the alignment mark is optimized, so that an average (a lateral shift when ΔZ=0) and variation (variation of the lateral shift within a range of the degree of focus error) of lateral shift ΔXAM is minimized. This allows the alignment mark to be designed with a small deformation, even if the mark is transferred in a defocused state.
30 Citations
63 Claims
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1. An exposure method in which a pattern is overlaid and formed in each of a plurality of first areas arranged on an object via a projection optical system, the method comprising:
performing a suppressing means of an exposure error occurring due to a positional shift of a second area in which a mark corresponding to the plurality of first areas and the first area corresponding to the mark within a plane orthogonal to an optical axis of the projection optical system when the pattern is formed in each of the plurality of first areas arranged on the object. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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38. An exposure method in which a pattern is overlaid and formed in each of a plurality of first areas arranged on an object, the method comprising:
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performing exposure to the object to reduce a step of a target portion, which is at least a part of a second area on which a plurality of first marks are formed corresponding to the plurality of first areas, with respect to the first area, by detecting the plurality of first marks and performing alignment of the object to a predetermined point based on results of the detection; and forming a second mark on the target portion and overlaying and forming the pattern in each of the plurality of first areas, by detecting the plurality of first marks, performing alignment of the object to a predetermined point based on results of the detection, and exposing the object. - View Dependent Claims (39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53)
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54. A device manufacturing method including overlaying and forming a pattern in each of a plurality of first areas arranged on an object, the method comprising:
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performing a flattening processing to flatten a target portion, which is at least a part of a second area on which a plurality of first marks are formed corresponding to the plurality of first areas, by detecting the plurality of first marks and performing alignment of the object to a predetermined point based on results of the detection; and detecting the plurality of first marks, performing alignment of the object to a predetermined point based on results of the detection, and forming a second mark on the target portion which has been flattened with respect to the first area. - View Dependent Claims (55, 56)
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57. An overlay error measurement method in which an overlay error for two patterns formed via a projection optical system on each of a reference layer and a target layer on an object is measured, the method comprising:
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optimizing a design condition of a mark by obtaining a first positional shift of an image of the pattern projected on the object via the projection optical system and an image of the mark within the plane orthogonal to the optical axis of the projection optical system, with respect to a second positional shift of the image of the pattern and the image of the mark in a direction parallel to the optical axis, and optimizing a design condition of the mark, based on the second positional shift and the corresponding first positional shift, for each of a plurality of conditions including an illumination condition to illuminate a mask on which the pattern and the mark are formed taking into consideration optical properties of the projection optical system; performing an exposure using a first mask on which a first pattern and a first mark whose positional relation is known is formed, so as to form the first pattern in a plurality of first areas on a reference layer of the object via the projection optical system, and at the same time, form the first mark in a second area corresponding to the plurality of first areas; performing an exposure using a second mask on which a first pattern and a second mark whose design condition is optimized by the optimizing and positional relation is known is formed, so as to form the second pattern on a target layer overlaying the first pattern on the object, and at the same time, form the second mark overlaying the first mark in the second area; and computing an overlay error of the first pattern and the second pattern, by measuring a positional shift of the first mark formed on the second area on the object and the second mark. - View Dependent Claims (58, 59)
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60. An overlay error measurement method in which an overlay error for two patterns formed via a projection optical system on each of a reference layer and a target layer on an object is measured, the method comprising:
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obtaining a first positional shift within a plane orthogonal to the optical axis of the projection optical system for an image of the pattern projected on a first area on the object via the projection optical system and an image of the mark projected on a second area on the object via the projection optical system, at least taking into consideration optical properties of the projection optical system; performing an exposure using a mask on which a first pattern and a first measurement mark whose positional relation is known is formed, so as to form the first pattern in the first area on a reference layer of the object via the projection optical system, and at the same time, form the first measurement mark in the second area; performing an exposure using a mask on which a second pattern and a second measurement mark is formed, so as to form the second pattern on a target layer overlaying the first pattern on the object, and at the same time, form the second mark overlaying the first mark in the second area; and computing an overlay error of the first pattern and the second pattern, by measuring a positional shift of the first measurement mark formed on the second area on the object and the second measurement mark. - View Dependent Claims (61, 62, 63)
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Specification