Focusing method, focusing apparatus, exposure method, and device manufacturing method
First Claim
1. A method of focusing an optical system on a second surface of a target object having an upper surface including a first surface and the second surface located below the first surface, wherein the target object has a step between the first surface and the second surface, the apparatus comprising:
- a first step of projecting oblique incidence light to the first surface at a first incident angle which forms a first angle with respect to a first direction parallel to an optical axis of the optical system, and receiving the light reflected by the first surface to measure a surface position of the first surface;
a second step of projecting oblique incidence light to the second surface at a second incident angle which forms a second angle smaller than the first angle with respect to the first direction, and receiving the light reflected by the second surface to measure a surface position of the second surface, wherein the second incident angle is determined so as to prevent the light reflected by the second surface from being reflected by the step between the first surface and the second surface;
a third step of obtaining, based on a measurement result of the surface position of the first surface, an in-focus condition in which the optical system is focused on the first surface;
a fourth step of obtaining information about a step amount between the first surface and the second surface based on the measurement result of the surface position of the first surface and a measurement result of the surface position of the second surface; and
a fifth step of focusing the optical system on the second surface based on the in-focus condition and the information about the step amount.
1 Assignment
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Accused Products
Abstract
A target object has an upper surface including a first surface and a second surface located below the first surface. A method of focusing an optical system includes: measuring a surface position of the first surface; measuring a surface position of the second surface; obtaining, based on a measurement results of the surface position of the first surface, an in-focus condition in which the optical system is focused on the first surface; obtaining information about a step amount between the first surface and the second surface based on the measurement results of the surface positions of the first surface and the second surface; and focusing the optical system on the second surface based on the in-focus condition and the information about the step amount.
14 Citations
18 Claims
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1. A method of focusing an optical system on a second surface of a target object having an upper surface including a first surface and the second surface located below the first surface, wherein the target object has a step between the first surface and the second surface, the apparatus comprising:
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a first step of projecting oblique incidence light to the first surface at a first incident angle which forms a first angle with respect to a first direction parallel to an optical axis of the optical system, and receiving the light reflected by the first surface to measure a surface position of the first surface; a second step of projecting oblique incidence light to the second surface at a second incident angle which forms a second angle smaller than the first angle with respect to the first direction, and receiving the light reflected by the second surface to measure a surface position of the second surface, wherein the second incident angle is determined so as to prevent the light reflected by the second surface from being reflected by the step between the first surface and the second surface; a third step of obtaining, based on a measurement result of the surface position of the first surface, an in-focus condition in which the optical system is focused on the first surface; a fourth step of obtaining information about a step amount between the first surface and the second surface based on the measurement result of the surface position of the first surface and a measurement result of the surface position of the second surface; and a fifth step of focusing the optical system on the second surface based on the in-focus condition and the information about the step amount. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An apparatus for focusing an optical system on a second surface of a target object having an upper surface including a first surface and the second surface located below the first surface, wherein the target object has a step between the first surface and the second surface, the apparatus comprising:
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a first oblique incidence surface position measurement device configured to project light to the first surface at a first incident angle which forms a first angle with respect to a first direction parallel to an optical axis of the optical system, and receive the light reflected by the first surface, thereby measuring a surface position of the first surface; a second oblique incidence surface position measurement device configured to project light to the second surface at a second incident angle which forms a second angle smaller than the first angle with respect to the first direction, and receive the light reflected by the second surface, thereby measuring a surface position of the second surface, wherein the second incident angle is determined so as to prevent the light reflected by the second surface from being reflected by the step between the first surface and the second surface; and a controller configured to obtain, based on a measurement result of the surface position of the first surface, an in-focus condition in which the optical system is focused on the first surface, obtain information about a step amount between the first surface and the second surface based on the measurement result of the surface position of the first surface and a measurement result of the surface position of the second surface, and focus the optical system on the second surface based on the in-focus condition and the information about the step amount. - View Dependent Claims (8)
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9. A method of projecting a pattern of a mask to each of a plurality of shot regions on a substrate via a projection optical system to expose the substrate,
each of the plurality of shot regions having an upper surface including a first surface and a second surface located below the first surface, wherein each of the plurality of shot regions has a step between the first surface and the second surface, the method comprising: -
a first step of projecting oblique incidence light to the first surface at a first incident angle which forms a first angle with respect to a first direction parallel to an optical axis of the projection optical system, and receiving the light reflected by the first surface to measure a surface position of the first surface; a second step of projecting oblique incidence light to the second surface at a second incident angle which forms a second angle smaller than the first angle with respect to the first direction, and receiving the light reflected by the second surface to measure a surface position of the second surface, wherein the second incident angle is determined so as to prevent the light reflected by the second surface from being reflected by the step between the first surface and the second surface; a third step of obtaining, based on a measurement result of the surface position of the first surface, an in-focus condition in which the projection optical system is focused on the first surface; a fourth step of obtaining information about a step amount between the first surface and the second surface based on the measurement result of the surface position of the first surface and a measurement result of the surface position of the second surface; a fifth step of focusing the projection optical system on the second surface based on the in-focus condition and the information about the step amount; and a sixth step of exposing the second surface of the target shot region on which the projection optical system is focused in the fifth step. - View Dependent Claims (10, 11, 12)
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13. A method of manufacturing a device, the method comprising:
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an exposure step of projecting a pattern of a mask to each of a plurality of shot regions on a substrate via a projection optical system to expose the substrate; a step of developing the exposed substrate; and a step of processing the developed substrate to manufacture the device, wherein each of the plurality of shot regions has an upper surface including a first surface and a second surface located below the first surface, wherein each of the plurality of shot regions has a step between the first surface and the second surface, and wherein the exposure step includes; a first step of projecting oblique incidence light to the first surface at a first incident angle which forms a first angle with respect to a first direction parallel to an optical axis of the projection optical system, and receiving the light reflected by the first surface to measure a surface position of the first surface; a second step of projecting oblique incidence light to the second surface at a second incident angle which forms a second angle smaller than the first angle with respect to the first direction, and receiving the light reflected by the second surface to measure a surface position of the second surface, wherein the second incident angle is determined so as to prevent the light reflected by the second surface from being reflected by the step between the first surface and the second surface; a third step of obtaining, based on a measurement result of the surface position of the first surface, an in-focus condition in which the projection optical system is focused on the first surface; a fourth step of obtaining information about a step amount between the first surface and the second surface based on the measurement result of the surface position of the first surface and a measurement result of the surface position of the second surface; a fifth step of focusing the projection optical system on the second surface based on the in-focus condition and the information about the step amount; and a sixth step of exposing the second surface of the target shot region on which the projection optical system is focused in the fifth step. - View Dependent Claims (14)
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15. A method of focusing an optical system on a second surface of a target object having an upper surface including a first surface and the second surface located below the first surface, comprising:
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a first step of projecting light to the first surface at a first incident angle which forms a first angle with respect to a first direction parallel to an optical axis of the optical system, and receiving the light reflected by the first surface to measure a surface position of the first surface, wherein the first angle is not smaller than 70°
;a second step of projecting light to the second surface at a second incident angle which forms a second angle smaller than the first angle with respect to the first direction, and receiving the light reflected by the second surface to measure a surface position of the second surface, wherein the second angle is not larger than 15°
;a third step of obtaining, based on a measurement result of the surface position of the first surface, an in-focus condition in which the optical system is focused on the first surface; a fourth step of obtaining information about a step amount between the first surface and the second surface based on the measurement result of the surface position of the first surface and a measurement result of the surface position of the second surface; and a fifth step of focusing the optical system on the second surface based on the in-focus condition and the information about the step amount.
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16. An apparatus for focusing an optical system on a second surface of a target object having an upper surface including a first surface and the second surface located below the first surface, comprising:
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a first measurement device configured to project light to the first surface at a first incident angle which forms a first angle with respect to a first direction parallel to an optical axis of the optical system, and receive the light reflected by the first surface, thereby measuring a surface position of the first surface, wherein the first angle is not smaller than 70°
;a second measurement device configured to project light to the second surface at a second incident angle which forms a second angle smaller than the first angle with respect to the first direction, and receive the light reflected by the second surface, thereby measuring a surface position of the second surface, wherein the second angle is not larger than 15°
; anda controller configured to obtain, based on a measurement result of the surface position of the first surface, an in-focus condition in which the optical system is focused on the first surface, obtain information about a step amount between the first surface and the second surface based on the measurement result of the surface position of the first surface and a measurement result of the surface position of the second surface, and focus the optical system on the second surface based on the in-focus condition and the information about the step amount.
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17. A method of projecting a pattern of a mask to each of a plurality of shot regions on a substrate via a projection optical system to expose the substrate,
each of the plurality of shot regions having an upper surface including a first surface and a second surface located below the first surface, the method comprising: -
a first step of projecting light to the first surface at a first incident angle which forms a first angle with respect to a first direction parallel to an optical axis of the projection optical system, and receiving the light reflected by the first surface to measure a surface position of the first surface, wherein the first angle is not smaller than 70°
;a second step of projecting light to the second surface at a second incident angle which forms a second angle smaller than the first angle with respect to the first direction, and receiving the light reflected by the second surface to measure a surface position of the second surface, wherein the second angle is not larger than 15°
;a third step of obtaining, based on a measurement result of the surface position of the first surface, an in-focus condition in which the projection optical system is focused on the first surface; a fourth step of obtaining information about a step amount between the first surface and the second surface based on the measurement result of the surface position of the first surface and a measurement result of the surface position of the second surface; a fifth step of focusing the projection optical system on the second surface based on the in-focus condition and the information about the step amount; and a sixth step of exposing the second surface of the target shot region on which the projection optical system is focused in the fifth step.
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18. A method of manufacturing a device, the method comprising:
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an exposure step of projecting a pattern of a mask to each of a plurality of shot regions on a substrate via a projection optical system to expose the substrate; a step of developing the exposed substrate; and a step of processing the developed substrate to manufacture the device, wherein each of the plurality of shot regions has an upper surface including a first surface and a second surface located below the first surface, wherein the exposure step includes; a first step of projecting light to the first surface at a first incident angle which forms a first angle with respect to a first direction parallel to an optical axis of the projection optical system, and receiving the light reflected by the first surface to measure a surface position of the first surface, wherein the first angle is not smaller than 70°
;a second step of projecting light to the second surface at a second incident angle which forms a second angle smaller than the first angle with respect to the first direction, and receiving the light reflected by the second surface to measure a surface position of the second surface, wherein the second angle is not larger than 15°
;a third step of obtaining, based on a measurement result of the surface position of the first surface, an in-focus condition in which the projection optical system is focused on the first surface; a fourth step of obtaining information about a step amount between the first surface and the second surface based on the measurement result of the surface position of the first surface and a measurement result of the surface position of the second surface; a fifth step of focusing the projection optical system on the second surface based on the in-focus condition and the information about the step amount; and a sixth step of exposing the second surface of the target shot region on which the projection optical system is focused in the fifth step.
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Specification