Detection apparatus and methods, exposure apparatus, exposure system and article manufacturing methods
By dividing the observation field into multiple sub-regions in the semiconductor exposure apparatus and using correction values to correct the detection values, the problems of poor measurement reproducibility and low alignment accuracy caused by defocus characteristics are solved, and an efficient and accurate alignment and measurement process is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CANON KK
- Filing Date
- 2021-12-03
- Publication Date
- 2026-05-26
AI Technical Summary
Existing technologies in semiconductor exposure apparatus suffer from poor measurement reproducibility and low alignment accuracy due to defocusing characteristics. This is especially true when using a pre-alignment optical system with a wide observation field for fine alignment measurements, where the edges of the observation field of the optical system are prone to defocusing, affecting measurement accuracy.
By dividing the observation field into multiple sub-regions in the detection optical system and combining the correction value with the detection value, the precise positioning and measurement of the alignment mark can be achieved. This includes a mark detection device and method formed on a substrate, which uses a processor to find the position of the mark in the observation field and performs correction based on a predetermined correction value.
It improves the accuracy and speed of the inspection process, enabling high-precision alignment measurements without being affected by defocusing characteristics, reducing alignment time and increasing production efficiency.
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Figure CN114624969B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a testing device, a testing method, an exposure device, an exposure system, and a method for manufacturing articles. Background Technology
[0002] Alignment of objects on a semiconductor exposure apparatus is typically performed by observing alignment marks on the object (e.g., a substrate) and detecting the position of these marks using a detection optics system. Detection optics systems can include pre-alignment optics with a wide field of view and fine alignment optics with a narrow field of view but high measurement accuracy. By first performing pre-alignment measurements using a pre-alignment optics system to roughly determine the position of the alignment marks, and then performing fine alignment measurements using a fine alignment optics system, alignment can be achieved with high measurement accuracy over a wide field of view. Recently, with the miniaturization of image sensors and the increase in pixel count, it has become possible to achieve high measurement accuracy while maintaining a wide field of view using pre-alignment optics systems.
[0003] On the other hand, there exists a defocus characteristic as an error factor, which can be included in alignment measurements using a detection optical system. The defocus characteristic represents the fluctuation in the focused position (measured value of the alignment mark) detected in the direction perpendicular to the optical axis (XY direction) depending on the position in the optical axis direction (Z direction) of the detection optical system. If the alignment mark is measured with defocus characteristics, then the change in the alignment mark's position in the Z direction manifests as a change in the measurement direction, which may reduce measurement reproducibility.
[0004] Japanese Patent Publication No. 10-022211 discloses adjusting the detection optical axis and the illumination optical axis to minimize the occurrence of defocus characteristics. In Japanese Patent Publication No. 10-022211, the defocus characteristics are adjusted by referring to an adjustment mark, and the position is detected provided that the actually aligned mark has the same defocus characteristics as the adjustment mark.
[0005] In fine alignment measurements, to minimize the impact of defocusing characteristics, it is desirable to measure alignment marks using a detection optical system focused at the optimal focal position. However, when attempting fine alignment measurements using a pre-alignment optical system with a wide field of view, it is impossible to focus across the entire field of view of the optical system. Therefore, even if the center of the field of view is in focus, the edges of the field of view may be out of focus. In this case, fine alignment measurements are not performed under optimal focusing conditions, and there may be problems with measurement deviations due to the effects of defocusing characteristics. In the case of an underlayer in a process wafer, the defocusing characteristics have a significant impact on the measurement values because the focal difference between the center and the edge of the field of view is amplified by the spacing caused by the underlayer. Therefore, in Japanese Patent Publication 2005-285916, after measuring the mark once, the wafer stage is moved so that the mark is near the center of the field of view of the optical system, and fine alignment measurements are performed again.
[0006] The technology disclosed in Japanese Patent Publication No. 10-022211 suffers from a lack of accuracy in achieving alignment because it cannot track changes in the alignment mark position and changes in defocus characteristics at the edge of the observation field. Furthermore, the method disclosed in Japanese Patent Publication No. 2005-285916 requires a single movement of the wafer stage to position the mark near the center of the observation field, and it also has the problem of requiring a long time to complete the alignment measurement. Summary of the Invention
[0007] The present invention provides a detection apparatus that is advantageous in terms of both accuracy and speed in achieving the detection process.
[0008] In a first aspect, the present invention provides a detection apparatus for detecting a mark formed on a substrate, comprising a stage that moves while holding the substrate, a detection optical system that illuminates a mark on the substrate held by the stage and detects an image of the mark, and a processor that performs a mark detection process based on the image of the mark detected by the detection optical system, wherein the processor is configured to find a detection value indicating the position of the mark in the observation field of the detection optical system based on the image of the mark detected by the detection optical system, find a sub-region where the mark is located in a plurality of sub-regions in the observation field, and correct the detection value based on a correction value corresponding to the found sub-region from among the correction values predetermined for the plurality of sub-regions respectively.
[0009] In a second aspect, the present invention provides a detection method for detecting the position of a mark using a detection optical system that illuminates a mark formed on a substrate held by a stage and detects an image of the mark. The method includes finding a detection value indicating the position of the mark in an observation field of the detection optical system based on the image of the mark detected by the detection optical system, finding a sub-region where the mark is located in a plurality of sub-regions in the observation field, and correcting the detection value based on a correction value corresponding to the found sub-region from among the correction values predetermined for the plurality of sub-regions.
[0010] In a third aspect, the present invention provides an exposure apparatus for exposing a substrate, comprising a detection device according to the first aspect, wherein the exposure apparatus exposes the substrate after correcting the detection result of the detection device for a mark formed on the substrate.
[0011] In its fourth aspect, the present invention provides an exposure system comprising a plurality of exposure devices, each exposure device having a detection device according to the second aspect, wherein information regarding a gap created in one of the plurality of exposure devices is shared by the plurality of exposure devices.
[0012] The present invention provides, in its fifth aspect, a method for manufacturing an article, comprising a first step of exposing a substrate using an exposure apparatus according to the third aspect or an exposure system according to the fourth aspect, and a second step of developing the substrate exposed in the first step, wherein an article is manufactured from the substrate developed in the second step.
[0013] Other features of the invention will become clear from the following description of exemplary embodiments (with reference to the accompanying drawings). Attached Figure Description
[0014] Figure 1 This is a diagram showing the configuration of the exposure apparatus.
[0015] Figure 2 This is a diagram showing the configuration of the detection optical system.
[0016] Figure 3 This is a diagram showing an example of a pre-alignment mark.
[0017] Figure 4 This is a diagram showing an example of fine alignment marks.
[0018] Figure 5 It is a flowchart of the measurement process for spacing information and defocus characteristics.
[0019] Figure 6 This is a diagram showing the state in which the fine alignment mark is located at the center of the observation field.
[0020] Figure 7This is a diagram illustrating the process of measuring the optimal focus position and defocus characteristics at various measurement points among multiple measurement points.
[0021] Figure 8 This is a diagram illustrating the process of creating a calibration table.
[0022] Figure 9 This is a flowchart of the process for correcting the precise alignment measurements.
[0023] Figure 10 This is a diagram showing the state of the fine alignment mark at the edge of the observation field.
[0024] Figure 11 This is a diagram illustrating the process of identifying the sub-region to which the fine alignment mark belongs.
[0025] Figure 12 This is a diagram illustrating a method for calculating the correction value of a fine alignment measurement.
[0026] Figure 13 This is a configuration diagram of an exposure system that shares spacing information between devices. Detailed Implementation
[0027] In the following, embodiments will be described in detail with reference to the accompanying drawings. It should be noted that the following embodiments are not intended to limit the scope of the claimed invention. Several features are described in the embodiments, but the invention is not limited to requiring all of these features, and several such features may be suitably combined. Furthermore, in the drawings, the same reference numerals are given the same or similar configuration, and redundant descriptions thereof are omitted.
[0028] <First Embodiment>
[0029] Figure 1 This is a schematic diagram of an exposure apparatus according to an embodiment. In this specification and the accompanying drawings, directions are shown in an XYZ coordinate system with the horizontal plane as the XY plane. Generally, the substrate 4 to be exposed is placed on a substrate stage 6 such that the surface of the substrate 4 is parallel to the horizontal plane (XY plane). Therefore, in the following text, mutually orthogonal directions in a plane along the surface of the substrate 4 are defined as the X-axis and Y-axis, and the direction perpendicular to the X-axis and Y-axis is defined as the Z-axis. Furthermore, in the following text, directions parallel to the X-axis, Y-axis, and Z-axis in the XYZ coordinate system are referred to as the X direction, Y direction, and Z direction, respectively, and rotation directions about the X-axis, Y-axis, and Z-axis are referred to as the θx direction, θy direction, and θz direction, respectively.
[0030] 1. Equipment Configuration
[0031] Figure 1This diagram illustrates the configuration of an exposure apparatus according to an embodiment, incorporating a detection device. The exposure apparatus 1 includes a projection optical system 3 that projects a pattern (e.g., a circuit pattern) formed on a template 2. Furthermore, the exposure apparatus 1 includes a template chuck 5 for holding a substrate 4 and a template stage 6 for positioning the substrate 4 at a predetermined position. The exposure apparatus 1 also includes a detection optical system 7 that illuminates alignment marks on the substrate 4 held by the template stage 6 and detects an image of the alignment marks. The pattern and alignment marks are formed on the substrate 4 in a preceding process.
[0032] The controller CN integrates and controls the various units of the exposure apparatus. The storage unit SU stores the programs and various data used by the controller CN to execute the exposure process. The controller CN and the storage unit SU can be configured as a computer device including a CPU and memory. Furthermore, in this embodiment, the controller CN can specifically be used as a processing unit to perform an alignment mark detection process based on an image of the alignment marks detected by the detection optical system 7.
[0033] Figure 2 This diagram illustrates the configuration of the detection optical system 7. Illumination light from the light source 8 is reflected by the beam splitter 9, passes through the lens 10, and illuminates the pre-alignment mark 11 on the substrate 4. The diffracted light from the pre-alignment mark 11 passes through the lens 10, the beam splitter 9, and the lens 13, and is received by the sensor 14. Here, the pre-alignment mark 11 is magnified by the lenses 10 and 13 at a predetermined magnification and imaged onto the sensor 14. Conventionally, different magnifications are set for pre-alignment measurements over a wide range and for fine alignment measurements requiring high precision; however, in this embodiment, the "predetermined magnification" is a magnification that can be appropriately used for both pre-alignment measurements and fine alignment measurements.
[0034] Figure 3 This is a diagram showing an example of pre-alignment mark 11, and Figure 4 This is a diagram illustrating an example of the fine alignment mark 12. The shapes of the pre-alignment mark 11 and the fine alignment mark 12 are not limited to those shown in the figures. The shapes of the individual alignment marks may vary depending on the stage of the substrate process, etc.
[0035] Although Figure 2 Although not specifically shown, an AF (autofocus) system (hereinafter referred to as the "OA-AF system") is configured in the detection optical system 7. Using this OA-AF system, the optimal focus position of the pre-alignment mark 11 or the fine alignment mark 12 can be calculated.
[0036] 2. Measurement of the distance information and defocus characteristics in the observation field.
[0037] Figure 5This is a flowchart of an exposure process that includes measuring spacing information and defocus characteristics in an observation field where fine alignment marks can be detected. The exposure process according to this flowchart can, for example, be performed when exposing the first substrate in each process.
[0038] In step S501, the controller CN controls the substrate conveyor (not shown) to convey the substrate into the exposure apparatus 1. The conveyed substrate is held by the substrate chuck 5.
[0039] In step S502, the controller CN (processing unit) calculates the position of the pre-alignment mark 11 on the substrate as the pre-alignment measurement result. At this time, by detecting the pre-alignment mark 11 in multiple imaging areas in the substrate, the offset and first-order linear components (magnification and / or rotation) of the entire substrate are calculated.
[0040] Following the pre-alignment measurement in step S502, in step S503, the controller CN performs a fine alignment measurement. Here, based on the result of the pre-alignment measurement, the controller CN drives the substrate stage 6 to a position where the detection optical system 7 can observe the position of the fine alignment mark 12, and detects the position of the fine alignment mark 12 in multiple imaging areas. Figure 4 In the example, the fine alignment mark 12 has a line-and-space pattern in which multiple lines are arranged at predetermined intervals in the X direction and a line-and-space pattern in which multiple lines are arranged at predetermined intervals in the Y direction. When the measurement direction is the X direction, the image of the fine alignment mark 12 acquired by the detection optical system 7 is integrated in the non-measurement direction (Y direction) to generate a one-dimensional waveform signal, and the signal is processed to find the position of the fine alignment mark 12 in the X direction. When the measurement direction is the Y direction, the image of the fine alignment mark 12 acquired by the detection optical system 7 is integrated in the non-measurement direction (X direction) to generate a one-dimensional waveform signal, and the signal is processed to find the position of the fine alignment mark 12 in the Y direction.
[0041] The controller CN then accurately calculates the offset and linear components (magnification and / or rotation) of the entire substrate. At this point, the controller CN can accurately calculate the higher-order deformation components of the substrate by measuring the position of the fine alignment marks 12 in multiple imaging areas. This allows for the precise calculation of the mark's position in each imaging area on the substrate.
[0042] In step S504, the controller CN uses the OA-AF system to measure the optimal focus position of the fine alignment mark 12 at the center of the observation field of the detection optical system 7 (refer to the optimal focus measurement). Figure 6The diagram shows the state in which the fine alignment mark 12 is positioned at the center 61 of the observation field. The optimal focusing position measured at the center 61 of the observation field is determined as the reference position for the spacing. Hereinafter, this is referred to as the "reference optimal focusing position," and this value is stored in the storage unit SU.
[0043] In step S505, the controller CN measures the optimal focus position and defocus characteristics at each of the multiple measurement points in the observation field. Defocus characteristics refer to the phenomenon that the position detected in the direction perpendicular to the optical axis (Z direction) (XY direction) (the measured value of the fine alignment mark 12) fluctuates depending on the focus position (depending on the amount of defocus) in the direction of the optical axis of the detection optical system 7. In step S505, the controller CN moves the substrate stage 6 so that the center of the fine alignment mark 12 coincides with one of the multiple measurement points in the observation field (e.g., measurement point 71), such that... Figure 7 As shown in the diagram. Next, the controller CN uses an OA-AF system to measure the optimal focus position and defocus characteristics of the fine alignment mark 12. Then, the controller CN moves the substrate stage 6 in the direction of arrow 72 so that the center of the fine alignment mark 12 coincides with the next measurement point, and measures the optimal focus position and defocus characteristics of the fine alignment mark 12. Similarly, measurements of the optimal focus position and defocus characteristics are performed at various measurement points among multiple measurement points in the observation field.
[0044] In step S506, the controller CN calculates the distance as the difference between the optimal focus position and the reference optimal focus position at each measurement point, and creates distance information with distance values at each measurement point. Furthermore, the controller CN obtains correction values based on the distance and defocus characteristics at each measurement point. For example, as... Figure 8 As shown, the controller CN obtains the product of the spacing and defocus characteristics for each measurement point as a correction value. The controller CN uses the correction values obtained for each of the multiple measurement points to create a correction table displaying the correspondence between the positions (XY coordinate values) of the multiple measurement points and the correction values. Since the defocus characteristics are measured for each measurement direction (X direction, Y direction) of the fine alignment mark 12, a correction table for the X direction and a correction table for the Y direction can be created. The created correction tables are stored in the storage unit SU. Steps S502 to S506 above describe the correction table creation process.
[0045] In step S507, the controller CN exposes each imaging area of the substrate. In step S508, the controller CN controls the substrate conveyor (not shown) to convey the substrate out of the exposure apparatus.
[0046] As described above, the exposure process according to the flowchart is performed, for example, when the first substrate is exposed in each process. However, if the fine alignment mark 12 is changed or the position of the measurement point is changed, the calibration table can be recreated.
[0047] 3. The process of precisely aligning and correcting the measured values.
[0048] Figure 9 This is a flowchart of the exposure process involving the correction of fine alignment measurements. The exposure process according to this flowchart can be performed during the exposure of the substrate, rather than during the exposure process involving the aforementioned spacing information and defocus characteristics.
[0049] In step S901, the controller CN controls the substrate conveyor (not shown) to transfer the substrate to the exposure apparatus 1. The transferred substrate is held by the substrate chuck 5.
[0050] In step S902, the controller CN measures the position of the fine alignment mark 12 without pre-alignment, i.e., it does not align the fine alignment mark 12 at the center of the field of view. Through this position measurement, a detection value (fine alignment measurement value) indicating the position of the fine alignment mark 12 in the observation field of the detection optical system 7 can be obtained. Because no pre-alignment is performed, it cannot be guaranteed that… Figure 6 The fine alignment mark 12 shown is positioned at the center of the observation field of the detection optical system 7. Therefore, as... Figure 10 As shown, there may be a situation where the fine alignment mark 12 is placed at a position that is off-center from the center of the observation field.
[0051] The observation field of the detection optical system 7 can be divided into multiple sub-regions, each centered around a measurement point among multiple measurement points. Figure 11 In the example, the observation field has 12 sub-regions, denoted by R1 to R12, and each sub-region shows the XY coordinate values and correction values of the measurement points. In an embodiment, each sub-region among the multiple sub-regions may have a size including the fine alignment mark 12. However, the size of each sub-region among the multiple sub-regions is not limited to the specific size associated with the fine alignment mark 12. In another embodiment, each sub-region among the multiple sub-regions may be smaller than the fine alignment mark 12. In step S903, the controller CN identifies one or more sub-regions containing the fine alignment mark 12 among the multiple sub-regions R1 to R12 based on the XY coordinate values of the fine alignment mark 12 measured in step S902. Figure 11In the example, the fine alignment mark 12 is located in sub-regions R1, R2, R7, and R8. The fine alignment mark 12 is surrounded by four points: the measurement point (x1, y1) in sub-region R1, the measurement point (x2, y2) in sub-region R2, the measurement point (x7, y7) in sub-region R7, and the measurement point (x8, y8) in sub-region R8.
[0052] In steps S904 and S905, the controller CN corrects the alignment measurement value based on one or more correction values obtained in step S903 from one of the multiple correction values pre-determined for each of the multiple sub-regions. For example, in step S904, the controller CN uses one or more correction values from one or more measurement points in one or more sub-regions specified in step S903 to calculate the correction value of the fine alignment measurement value as the mark detection result.
[0053] As described above, in this embodiment, each of the multiple sub-regions has a size capable of including the fine alignment mark 12. When the center of the fine alignment mark 12 coincides with the center of a sub-region, a preset correction value in that sub-region can be taken as the correction value of the fine alignment mark 12. If the center of the fine alignment mark 12 does not coincide with the center of a sub-region, then the fine alignment mark 12 will span two or more sub-regions. Figure 11 The example shown illustrates this situation. In this case, the correction value for the fine alignment measurement is obtained by taking a weighted average of the correction values of the measurement points in the sub-region specified in step S903.
[0054] Reference Figure 12 This describes a method for calculating the correction values of fine alignment measurements. Here, let M1 be the center of fine alignment mark 12. Furthermore, let the correction values 1, 2, 7, and 8 of the sub-regions R1, R2, R7, and R8 to which fine alignment mark 12 belongs be C1(xc1, yc1), C2(xc2, yc2), C7(xc7, yc7), and C8(xc8, yc8), respectively. First, the controller CN finds the sub-region (first sub-region) where the center M1 of fine alignment mark 12 is located. Figure 12In the example, the sub-region where the center M1 of the fine alignment mark 12 is located is sub-region R1. Next, the controller CN finds the correction value by taking a weighted average of predetermined correction values for sub-regions R1, R2, R7, and R8 based on the amount of misalignment between the center M1 of the fine alignment mark 12 and the center of sub-region R1. Based on the amount of misalignment between the center M1 of the fine alignment mark 12 and the center of sub-region R1, a ratio representing the position of M1 in the X direction and a ratio representing the position of M1 in the Y direction can be obtained in a rectangular region with the measurement point around the center M1 as the vertex. As described above, since a correction table is created for each measurement direction, corrected correction values are also obtained for the X and Y directions. The corrected correction value for the fine alignment mark 12 in the X direction is obtained using the following formula.
[0055] (1-b)*(xc1*(1-a)+xc2*a)+b*(xc7*a+xc8*(1-a))
[0056] Furthermore, the corrected value for the fine alignment mark 12 in the Y direction is obtained using the following formula.
[0057] (1-a)*(yc1*(1-b)+yc8*b)+a*(yc7*b+yc2*(1-b))
[0058] Next, in step S905, the controller CN uses the corrected correction values calculated in step S904 to correct the fine alignment measurements. Note that the corrected correction values calculated in step S904 are not limited to a weighted average. For example, when the measurement accuracy of individual correction values is low, a planar approximation using a correction value table can be used. After correcting the fine alignment measurements, the controller CN accurately calculates the offset and first-order linear components (magnification and / or rotation) of the entire substrate based on the corrected fine alignment measurements.
[0059] Next, in step S906, the controller CN exposes each imaging area of the substrate. In step S907, the controller CN controls the substrate conveyor (not shown) to convey the substrate out of the exposure apparatus.
[0060] According to the above exposure process, the process of aligning the fine alignment mark 12 with the center of the observation field is not performed, and even if the fine alignment mark 12 is measured when it is located at the edge of the observation field of the detection optical system 7, a highly accurate measurement can be performed without being affected by the defocus characteristics.
[0061] It should be noted that this embodiment can be applied to image detection methods and diffraction light detection methods.
[0062] <Second Embodiment>
[0063] In the first embodiment described above, a method for creating a calibration table for each process and using the calibration table to correct fine alignment measurements during exposure has been described. In the second embodiment, sharing spacing information between devices when creating the calibration table will be described.
[0064] Figure 13 This is a configuration diagram of an exposure system that shares spacing information among multiple exposure units. The exposure system includes multiple exposure units, each having the aforementioned detection device. There is a case where the spacing information around the fine alignment mark 12 is stable for the same process. In this case, instead of performing optimal focus measurements at multiple measurement points in each of the first exposure unit (unit A) and the second exposure unit (unit B) in the same manner, the spacing information obtained through the measurement in unit A can be used in unit B. The spacing information generated through the measurement in unit A is stored in an external storage device. Unit B can access the external storage device to obtain and use the spacing information of the same process.
[0065] By sharing spacing information among multiple exposure devices in this way, device B can omit optimal focus measurements at multiple measurement points and can expect increased productivity.
[0066] <Example of Article Manufacturing Method>
[0067] The article manufacturing method according to embodiments of the present invention is applicable, for example, to the manufacture of articles such as microdevices (such as semiconductor devices) and components with fine structures. The article manufacturing method of this embodiment includes the step of forming a latent image pattern on a photosensitive agent applied to a substrate using the aforementioned exposure apparatus (the substrate exposure step), and the step of developing the substrate on which the latent image pattern was formed in the aforementioned step. Furthermore, such a manufacturing method includes other well-known steps (oxidation, film formation, vapor deposition, doping, planarization, etching, resist stripping, dicing, bonding, encapsulation, etc.). Compared to conventional methods, the article manufacturing method of this embodiment is advantageous in at least one aspect of article performance, quality, productivity, and production cost.
[0068] <Other Embodiments>
[0069] One or more embodiments of the present invention can also be implemented by a computer that reads and executes computer-executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be more fully referred to as a "non-transitory computer-readable storage medium") to perform the functions of one or more embodiments described above and / or includes one or more circuits (e.g., application-specific integrated circuits (ASICs)) for performing the functions of one or more embodiments described above, and by a method performed by a computer of a system or device by, for example, reading and executing computer-executable instructions from a storage medium to perform the functions of one or more embodiments described above and / or controlling one or more circuits to perform the functions of one or more embodiments described above. The computer may include one or more processors (e.g., a central processing unit (CPU), a microprocessor unit (MPU)) and may include a network of individual computers or individual processors to read and execute computer-executable instructions. The computer-executable instructions may be provided to the computer, for example, from a network or a storage medium. The storage medium may include, for example, a hard disk, random access memory (RAM), read-only memory (ROM), a storage device for a distributed computing system, an optical disc (such as a CD, DVD, or Blu-ray disc), or a digital versatile disc (BD). TM One or more of the following: flash memory devices, memory cards, etc.
[0070] The embodiments of the present invention can also be implemented by providing software (programs) that perform the functions of the above embodiments to a system or device via a network or various storage media, and the computer or central processing unit (CPU) or microprocessor unit (MPU) of the system or device reads out and executes the program.
[0071] While the invention has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the appended claims should be given the broadest interpretation to cover all such modifications and equivalent structures and functions.
Claims
1. A detection device for detecting marks formed on a substrate, the detection device comprising: An optical detection system illuminates a mark on a substrate and detects the image of the mark. as well as The processor, based on an image of the marker detected by the detection optical system, performs the marker detection process. The processor is configured as follows: Based on the image of the marker detected by the detection optical system, the position of the marker in the observation field of the detection optical system is specified, and The position of the marker is corrected based on the correction value calculated for each of the multiple positions within the observation field based on the optimal focus position and defocus characteristics.
2. The detection device according to claim 1, wherein, In cases where the marker spans two or more sub-regions within a plurality of sub-regions in the observation field, the processor is configured to: Specify the first sub-region, which is the sub-region where the center of the marker is located. The corrected value is specified by taking a weighted average of predetermined correction values for each of the two or more sub-regions, using a weight that depends on the positional offset between the center of the marker and the center of the first sub-region. The position of the mark is corrected using the corrected correction value.
3. The detection device according to claim 1, wherein the processor is configured to: The process of creating a calibration table is executed. This calibration table shows the relationship between the positions of multiple measurement points and calibration values set for multiple sub-regions within the observation field. Based on the correction table pre-created through the creation process, correction values are specified for the plurality of sub-regions, and The creation process includes: The optimal focusing position of the fine alignment mark is measured at the center of the observation field of the detection optical system, and this measured optimal focusing position is determined as the reference position. The optimal focus position and defocus characteristics of the fine alignment mark are measured at each of the plurality of measurement points. For each of the plurality of measurement points, a correction value is specified based on the spacing between the difference between the optimal focusing position and the reference position, as well as the defocus characteristics. A calibration table is created using the calibration values found for each of the plurality of measurement points.
4. The detection apparatus of claim 3 further includes a stage configured to move while holding the substrate. The creation process also includes a pre-alignment measurement and a fine alignment measurement following the pre-alignment measurement, and After moving the stage based on the results of the fine alignment measurement, the optimal focusing position of the fine alignment mark is measured at the center of the observation field of the detection optical system.
5. The detection apparatus according to claim 3, wherein the defocus characteristic shows that the measured value of the fine alignment mark fluctuates depending on the amount of defocus of the detection optics.
6. A detection method for detecting the position of a mark using a detection optical system, said detection optical system illuminating a mark formed on a substrate with light and detecting an image of the mark, the method comprising: Based on the image of the marker detected by the detection optical system, specify the position of the marker in the observation field of the detection optical system; as well as The position of the marker is corrected based on the correction value calculated for each of the multiple positions within the observation field based on the optimal focus position and defocus characteristics.
7. An exposure apparatus for exposing a substrate, said exposure apparatus include: The detection device according to claim 1, The exposure device exposes the substrate after the detection results of the marks formed on the substrate have been corrected by the detection device.
8. An exposure system comprising a plurality of exposure devices, each exposure device having a detection device according to claim 3, wherein information regarding a spacing created in one of the plurality of exposure devices is shared by the plurality of exposure devices.
9. A method for manufacturing an article, comprising: The first step of exposing the substrate using the exposure apparatus according to claim 7 or the exposure system according to claim 8; as well as The second step involves developing the substrate exposed in the first step. Articles are manufactured from the substrate developed in the second step.