Method for evaluating and improving pupil luminance distribution, illumination optical system and adjustment method thereof, exposure apparatus, exposure method, and device manufacturing method
First Claim
1. An adjustment method of an illumination optical system, the illumination optical system illuminating an irradiation target surface by light from a light source and supplying illumination light to an image-forming optical system that forms an image of a pattern placed on a first plane on a second plane, the method comprising:
- adjusting a pupil luminance distribution to be formed on an illumination pupil of the illumination optical system; and
changing the pupil luminance distribution to be formed on the illumination pupil, with the adjusted pupil luminance distribution serving as a target, whereinthe adjusting comprises;
a process of acquiring an index value obtained from a pupil luminance distribution formed on the illumination pupil with a standard pupil luminance distribution serving as a target, using a predetermined evaluation method, whereinthe evaluation method includes;
preparing a variation table that shows a variation of an intensity distribution of the image of the pattern with respect to a change in a pupil luminance for each of a plurality of unit pupil areas, the preparing including a first process of acquiring, for each unit pupil area, a unit intensity distribution formed on the second plane by light of a unit luminance level supplied from each unit pupil area, the plurality of unit pupil areas being obtainable by virtually dividing the illumination pupil;
calculating, by using luminance for each of the plurality of unit pupil areas of the pupil luminance distribution subject to evaluation and the variation table, the intensity distribution of the image of the pattern that is formed on the second plane with light from the pupil luminance distribution subject to evaluation, the calculating including a second process of acquiring discrete data of the pupil luminance distribution wherein each area of the plurality of unit pupil areas is approximated according to a three-dimensional model having a luminance level expressed by a multiple of the unit luminance level, and a third process of acquiring a light intensity distribution of an aerial image formed on the second plane from the pupil luminance distribution, based on a plurality of the unit intensity distributions acquired for each unit pupil area in the first process, and the discrete data acquired in the second process; and
acquiring, by using the calculated intensity distribution of the image, an index value of image-forming property obtained according to the pupil luminance distribution subject to evaluation, the acquiring including a fourth process of acquiring an index value of image-forming property obtained from the pupil luminance distribution, based on the light intensity distribution of the aerial image acquired in the third process, andthe adjusting further comprises;
a process of acquiring a unit change amount of the index value for each unit pupil area when a luminance level of one unit pupil area changes only by a unit luminance level in the discrete data acquired in a preceding process;
a process of acquiring discrete data modulated from the discrete data acquired in the preceding process, by an adjusting technique using the unit change amounts of a plurality of the index values that have been acquired, so as to make an index value obtained from the modulated discrete data approach a target index value; and
a process of acquiring an index value obtained corresponding to the modulated discrete data that has been acquired, using the evaluation method, whereinby repeatedly performing the process of acquiring the unit change amount of the index value for each unit pupil area, the process of acquiring the discrete data modulated and the process of acquiring the index value until a difference between the index value obtained corresponding to the modulated discrete data and the target index value falls within a permissible range, the pupil luminance distribution to be formed on the illumination pupil is adjusted.
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Accused Products
Abstract
Improvement of pupil luminance distribution includes: a fifth process in which an index value obtained from the illumination pupil, using evaluation method of a first process to fourth process; a sixth process wherein a unit change amount of the index value in the discrete data acquired in the previous process is acquired for each unit pupil area; a seventh process wherein discrete data modulated by an improving technique using the unit change amount so that the index value nears a target index value is acquired; and an eighth process wherein an index value obtained corresponding to the modulated discrete data in the seventh process is acquired, using the evaluation method of the first process to the fourth process, and by repeatedly performing the sixth process to eighth process so an error of the index value obtained corresponding to the modulated discrete data falls within permissible range.
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Citations
49 Claims
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1. An adjustment method of an illumination optical system, the illumination optical system illuminating an irradiation target surface by light from a light source and supplying illumination light to an image-forming optical system that forms an image of a pattern placed on a first plane on a second plane, the method comprising:
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adjusting a pupil luminance distribution to be formed on an illumination pupil of the illumination optical system; and changing the pupil luminance distribution to be formed on the illumination pupil, with the adjusted pupil luminance distribution serving as a target, wherein the adjusting comprises; a process of acquiring an index value obtained from a pupil luminance distribution formed on the illumination pupil with a standard pupil luminance distribution serving as a target, using a predetermined evaluation method, wherein the evaluation method includes; preparing a variation table that shows a variation of an intensity distribution of the image of the pattern with respect to a change in a pupil luminance for each of a plurality of unit pupil areas, the preparing including a first process of acquiring, for each unit pupil area, a unit intensity distribution formed on the second plane by light of a unit luminance level supplied from each unit pupil area, the plurality of unit pupil areas being obtainable by virtually dividing the illumination pupil; calculating, by using luminance for each of the plurality of unit pupil areas of the pupil luminance distribution subject to evaluation and the variation table, the intensity distribution of the image of the pattern that is formed on the second plane with light from the pupil luminance distribution subject to evaluation, the calculating including a second process of acquiring discrete data of the pupil luminance distribution wherein each area of the plurality of unit pupil areas is approximated according to a three-dimensional model having a luminance level expressed by a multiple of the unit luminance level, and a third process of acquiring a light intensity distribution of an aerial image formed on the second plane from the pupil luminance distribution, based on a plurality of the unit intensity distributions acquired for each unit pupil area in the first process, and the discrete data acquired in the second process; and acquiring, by using the calculated intensity distribution of the image, an index value of image-forming property obtained according to the pupil luminance distribution subject to evaluation, the acquiring including a fourth process of acquiring an index value of image-forming property obtained from the pupil luminance distribution, based on the light intensity distribution of the aerial image acquired in the third process, and the adjusting further comprises; a process of acquiring a unit change amount of the index value for each unit pupil area when a luminance level of one unit pupil area changes only by a unit luminance level in the discrete data acquired in a preceding process; a process of acquiring discrete data modulated from the discrete data acquired in the preceding process, by an adjusting technique using the unit change amounts of a plurality of the index values that have been acquired, so as to make an index value obtained from the modulated discrete data approach a target index value; and a process of acquiring an index value obtained corresponding to the modulated discrete data that has been acquired, using the evaluation method, wherein by repeatedly performing the process of acquiring the unit change amount of the index value for each unit pupil area, the process of acquiring the discrete data modulated and the process of acquiring the index value until a difference between the index value obtained corresponding to the modulated discrete data and the target index value falls within a permissible range, the pupil luminance distribution to be formed on the illumination pupil is adjusted. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. An adjustment method of an illumination optical system, the illumination optical system illuminating an irradiation target surface by light from a light source and supplying illumination light to an image-forming optical system that forms an image of a pattern placed on a first plane on a second plane, the method comprising:
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evaluating a pupil luminance distribution formed on an illumination pupil of the illumination optical system; and adjusting the pupil luminance distribution formed on the illumination pupil based on a result of the evaluating, wherein the evaluating comprises; preparing a variation table that shows a variation of an intensity distribution of the image of the pattern with respect to a change in a pupil luminance for each of a plurality of unit pupil areas on the illumination pupil, the preparing including a first process of acquiring, for each of a plurality of unit pupil areas, a unit intensity distribution formed on the second plane by light of a unit luminance level supplied from each unit pupil area, the plurality of unit pupil areas being obtained by virtually dividing the illumination pupil, calculating, by using luminance for each of the plurality of unit pupil areas of the pupil luminance distribution subject to evaluation and the variation table, the intensity distribution of the image of the pattern that is formed on the second plane with light from the pupil luminance distribution subject to evaluation, the calculating including a second process of acquiring discrete data of a standard pupil luminance distribution, according to a three-dimensional model in which each area of the plurality of unit pupil areas has a luminance level expressed by a multiple of the unit luminance level, and a third process of acquiring a light intensity distribution of an aerial image formed on the second plane from the standard pupil luminance distribution, based on the plurality of the unit intensity distributions acquired for each unit pupil area in the first process and the discrete data of the standard pupil luminance distribution acquired in the second process; acquiring, by using the calculated intensity distribution of the image, an index value of image-forming property obtained according to the pupil luminance distribution subject to evaluation, the acquiring including a fourth process of acquiring an index value of image-forming property obtained from the standard pupil luminance distribution, based on the light intensity distribution of the aerial image acquired in the third process; and acquiring, for each unit pupil area, a unit change amount of the index value obtained when the luminance level of one unit pupil area changes only by a unit luminance level in the discrete data of the standard pupil luminance distribution. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43)
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44. An illumination optical system that illuminates an irradiation target surface by light from a light source, and supplies illumination light to an image-forming optical system that forms an image of a pattern placed on a first plane on a second plane, the system comprising:
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a pupil distribution measurement device that measures a pupil luminance distribution formed on an illumination pupil of the illumination optical system; a pupil adjustment device that adjusts the pupil luminance distribution formed on the illumination pupil; and a controller that controls the pupil adjustment device to change the pupil luminance distribution formed on the illumination pupil with the pupil luminance distribution adjusted using an adjustment method, as a target, the adjustment method adjusting a pupil luminance distribution to be formed on the illumination pupil of the illumination optical system, wherein the adjustment method comprises; a process of acquiring an index value obtained from a pupil luminance distribution formed on the illumination pupil with a standard pupil luminance distribution serving as a target, using a predetermined evaluation method, wherein the evaluation method includes; preparing a variation table that shows a variation of an intensity distribution of the image of the pattern with respect to a change in a pupil luminance for each of a plurality of unit pupil areas, the preparing including a first process of acquiring, for each unit pupil area, a unit intensity distribution formed on the second plane by light of a unit luminance level supplied from each unit pupil area, the plurality of unit pupil areas being obtainable by virtually dividing the illumination pupil; calculating, by using luminance for each of the plurality of unit pupil areas of the pupil luminance distribution subject to evaluation and the variation table, the intensity distribution of the image of the pattern that is formed on the second plane with light from the pupil luminance distribution subject to evaluation, the calculating including a second process of acquiring discrete data of the pupil luminance distribution wherein each area of the plurality of unit pupil areas is approximated according to a three-dimensional model having a luminance level expressed by a multiple of the unit luminance level, and a third process of acquiring a light intensity distribution of an aerial image formed on the second plane from the pupil luminance distribution, based on a plurality of the unit intensity distributions acquired for each unit pupil area in the first process, and the discrete data acquired in the second process; and acquiring, by using the calculated intensity distribution of the image, an index value of image-forming property obtained according to the pupil luminance distribution subject to evaluation, the acquiring including a fourth process of acquiring an index value of image-forming property obtained from the pupil luminance distribution, based on the light intensity distribution of the aerial image acquired in the third process, and the adjustment method further comprises; a process of acquiring a unit change amount of the index value for each unit pupil area when a luminance level of one unit pupil area changes only by a unit luminance level in the discrete data acquired in a preceding process; a process of acquiring discrete data modulated from the discrete data acquired in the preceding process by an adjusting technique using the unit change amounts of a plurality of the index values that have been acquired so as to make an index value obtained from the modulated discrete data approach a target index value; and a process of acquiring an index value obtained corresponding to the modulated discrete data that has been acquired, using the evaluation method, wherein by repeatedly performing the process of acquiring the unit change amount of the index value for each unit pupil area, the process of acquiring the discrete data modulated and the process of acquiring the index value until a difference between the index value obtained corresponding to the modulated discrete data and the target index value falls within a permissible range, the pupil luminance distribution to be formed on the illumination pupil is adjusted.
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45. An illumination optical system that illuminates an irradiation target surface by light from a light source, and supplies illumination light to an image-forming optical system that forms an image of a pattern placed on a first plane on a second plane, the system comprising:
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a pupil distribution measurement device that measures a pupil luminance distribution formed on an illumination pupil of the illumination optical system; a pupil adjustment device that adjusts the pupil luminance distribution formed on the illumination pupil; and a controller that controls the pupil adjustment device to adjust the pupil luminance distribution formed on the illumination pupil using a predetermined adjustment method, wherein the adjustment method comprises; a process of adjusting the pupil luminance distribution formed on the illumination pupil of the illumination optical system based on a result of evaluating the pupil luminance distribution formed on the illumination pupil using a predetermined evaluation method, wherein the evaluation method includes; preparing a variation table that shows a variation of an intensity distribution of the image of the pattern with respect to a change in a pupil luminance for each of a plurality of unit pupil areas, the preparing including a first process of acquiring, for each unit pupil area, a unit intensity distribution formed on the second plane by light of a unit luminance level supplied from each unit pupil area, the plurality of unit pupil areas being obtained by virtually dividing the illumination pupil; calculating, by using luminance for each of the plurality of unit pupil areas of the pupil luminance distribution subject to evaluation and the variation table, the intensity distribution of the image of the pattern that is formed on the second plane with light from the pupil luminance distribution subject to evaluation, the calculating including a second process of acquiring discrete data of a standard pupil luminance distribution, according to a three-dimensional model in which each area of the plurality of unit pupil areas has a luminance level expressed by a multiple of the unit luminance level, and a third process of acquiring a light intensity distribution of an aerial image formed on the second plane from the standard pupil luminance distribution, based on the plurality of the unit intensity distributions acquired for each unit pupil area in the first process and the discrete data of the standard pupil luminance distribution acquired in the second process; acquiring, by using the calculated intensity distribution of the image, an index value of image-forming property obtained according to the pupil luminance distribution subject to evaluation, the acquiring including a fourth process of acquiring an index value of image-forming property obtained from the standard pupil luminance distribution, based on the light intensity distribution of the aerial image acquired in the third process; and acquiring, for each unit pupil area, a unit change amount of the index value obtained when the luminance level of one unit pupil area changes only by a unit luminance level in the discrete data of the standard pupil luminance distribution. - View Dependent Claims (46, 47, 48, 49)
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Specification