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 a second surface located below the first surface, 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 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 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;
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.
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Citations
10 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 a 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; 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; 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)
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6. An apparatus for focusing an optical system on a second surface of a target object having an upper surface including a first surface and a 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; 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; 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.
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7. 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; 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; 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 (8, 9)
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10. 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; 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; 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