Exposure apparatus, measurement method, and article manufacturing method

Abstract

The present disclosure relates to an exposure apparatus, a measurement method, and a method of manufacturing an article, which measure an original plate mark with high precision. Provided is an exposure device for transferring a pattern of an original plate to a substrate, the exposure apparatus includes: an original plate mounting table on which an original plate support device for holding the original plate is mounted; a measurement unit for irradiating measurement light onto an original plate mark provided on the original plate to measure the measurement light reflected by the original plate mark; a light shielding unit for shielding the measurement light; and a control unit for controlling the driving of the light shielding unit. The control unit controls the light shielding unit disposed at a position where the measurement light is not shielded so that the light shielding unit shields the measurement light that has passed through the original plate mark at a timing when the original plate mark is measured by the measurement unit.

Description

Technical Field

[0001] This disclosure relates to an exposure apparatus, a measurement method, and a method for manufacturing an article. Background Technology

[0002] As one of the photolithography apparatuses used in the manufacturing processes of semiconductor devices, flat panel displays (FPDs), etc., there exists an exposure apparatus that transfers the pattern of a master plate mounted on a master plate stage onto a substrate. In order to transfer the pattern of the master plate onto the substrate with high precision, the positional deviation of the master plate relative to the master plate stage can be measured by detecting the reference mark set on the master plate stage and the master plate mark set on the master plate using an observation instrument.

[0003] In exposure apparatuses, it is required to mount various types of original plates on a stage. In this case, the relative position of the reference mark and the original plate mark when the original plate is mounted on the stage may differ depending on the type of original plate. Therefore, it is required to measure the positional deviation of the original plate relative to the stage with high precision, based on the type of original plate mounted on the stage.

[0004] Japanese Patent Application Publication No. 2003-007609 describes a method of mounting a copy smaller than the specified size of the copy that can be mounted on a mounting platform by using a support device that retains the peripheral parts of the copy.

[0005] In Japanese Patent Application Publication No. 2003-007609, the positional deviation of the support device relative to the mounting platform is measured by detecting the difference between a mark set on the support device and a reference mark on the original mounting platform. Based on this measurement result, the positional deviation of the original plate relative to the mounting platform is calculated. However, when using a support device to mount the original plate on the mounting platform, the relative positions of the support device and the original plate sometimes deviate. Therefore, the method described in Japanese Patent Application Publication No. 2003-007609 may not be sufficient to measure the positional deviation of the original plate relative to the mounting platform with high precision. Summary of the Invention

[0006] To achieve the above objectives, an exposure apparatus, as one aspect of this disclosure, transfers a pattern of a master plate onto a substrate. The exposure apparatus is characterized by comprising a master plate stage equipped with a master plate support for holding the master plate; a measurement unit that illuminates a master plate mark disposed on the master plate with measurement light and measures the measurement light reflected from the master plate mark; a light-shielding unit that blocks the measurement light; and a control unit that controls the driving of the light-shielding unit, wherein the control unit controls the light-shielding unit positioned in a position that does not block the measurement light, such that when the measurement unit measures the master plate mark, the light-shielding unit blocks the measurement light passing through the master plate mark.

[0007] Further features of this disclosure will become apparent from the following description of exemplary embodiments (with reference to the accompanying drawings). Attached Figure Description

[0008] Figure 1 This is a schematic diagram showing the structure of the exposure apparatus.

[0009] Figure 2 It is a three-dimensional view showing the structure of the original support device.

[0010] Figure 3 This is a side view showing the structure of the original support device.

[0011] Figure 4 It is a diagram used to illustrate the location of the markers.

[0012] Figure 5 This is a flowchart of the alignment measurement.

[0013] Figure 6 It is a flowchart of the manufacturing process of the item. Detailed Implementation

[0014] Preferred embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. Furthermore, in the drawings, the same reference numerals are used for the same components, and repeated descriptions are omitted.

[0015] In this specification and accompanying drawings, directions are represented by an XYZ coordinate system, with the X and Y directions being mutually orthogonal directions in a plane parallel to the holding surface of the original plate mounting platform. The directions parallel to the X, Y, and Z axes in the XYZ coordinate system are designated as the X, Y, and Z directions, respectively.

[0016] Control and drive (movement) related to the X-axis, Y-axis, and Z-axis respectively mean control or drive (movement) related to the direction parallel to the X-axis, the direction parallel to the Y-axis, and the direction parallel to the Z-axis.

[0017] This embodiment will be described. As one of the photolithography apparatuses used in the manufacturing process of semiconductor devices, flat panel displays (FPDs), etc., an exposure apparatus is known.

[0018] An exposure apparatus is a device that performs an exposure process by exposing a substrate through a master plate to transfer (form) a pattern formed on a master plate onto the substrate. Among methods of exposing multiple imaging areas on the substrate separately, there are step-repetition and step-scanning methods. An exposure apparatus using the step-repetition method is sometimes called a stepper, which sequentially performs an exposure process on each imaging area of ​​the substrate to transfer the pattern of the master plate onto the substrate. On the other hand, an exposure apparatus using the step-scanning method is sometimes called a scanner, which sequentially performs an exposure process on each imaging area of ​​the substrate while scanning the master plate and the substrate relative to each other to transfer the pattern of the master plate onto the substrate. In this embodiment, an exposure apparatus using the step-scanning method will be described as an example, with the relative scanning direction between the master plate and the substrate in this exposure apparatus set to the Y direction.

[0019] Figure 1 This is a schematic diagram showing the structure of the exposure apparatus EXP. The exposure apparatus EXP includes a master plate stage 4 for mounting the master plate 3, a substrate stage 7 for mounting the substrate 6, an alignment measurement unit 2 (measurement unit) for illuminating alignment marks, and a control unit 11. Furthermore, the exposure apparatus EXP includes an illumination optical system 1 for illuminating the master plate 3, a projection optical system 5 for projecting the pattern of the master plate 3 onto the substrate 6, and light-shielding mechanisms 9a and 9b (light-shielding parts) that can be driven to block light passing through the projection optical system 5. The master plate 3 and the substrate 6 are positioned at approximately optically conjugate positions (object plane and image plane of the projection optical system 5) across the projection optical system 5.

[0020] The alignment measurement unit 2 includes an irradiation unit that irradiates measurement light and a light-receiving unit that receives measurement light reflected from marks, etc. The irradiation unit is composed of light-emitting diodes, etc., and can change the illuminance of the irradiated light. The light-receiving unit is composed of sensors, etc. The alignment measurement unit 2 can be driven in the XY direction by a drive mechanism (not shown) to measure the reflected light when the reference mark group 8 on the original plate mounting stage 4 and the alignment mark group 10 on the original plate are irradiated. In addition, the alignment measurement unit 2 has a focus adjustment mechanism (not shown) that can change the focus (position in the Z direction) according to the measurement mark to perform the measurement.

[0021] The control unit 11 determines and controls the drive amount of each drive mechanism of the exposure apparatus EXP. The control unit 11 includes a data holding unit 12, a drive amount calculation unit 13 (calculation unit), and a drive indication unit 14. The data holding unit 12 holds the mark position information measured by the alignment measurement unit 2, drive parameters such as drive offset and sensitivity of various drive axes, and various measurement data obtained by the exposure apparatus.

[0022] The drive quantity calculation unit 13 determines the drive instruction quantities for the master stage 4, substrate stage 7, etc., during exposure. The drive instruction unit 14 outputs drive instructions for each drive mechanism using the drive instruction quantities determined by the drive quantity calculation unit 13. Furthermore, regarding the control unit 11, its hardware structure is, for example, constituted by a computer device including a CPU (central processing unit) and memory. In this case, the data holding unit 12 is implemented using memory, and the drive quantity calculation unit 13 and the drive instruction unit 14 are implemented using the CPU.

[0023] The illumination optical system 1 includes a light source (not shown) such as an ultra-high pressure mercury lamp, a wavelength selective filter, a lens group, and a shutter. The illumination optical system 1 illuminates the original plate 3 with light of a wavelength suitable for exposure. The original plate stage 4, on which the original plate 3 is mounted, is scanned in the Y direction by a drive mechanism (not shown) under the control of the control unit 11.

[0024] A reflector (not shown) is placed on the original mounting stage 4 to reflect measurement light from a laser interferometer (not shown) located outside the original mounting stage 4. The laser interferometer receives the reflected measurement light and continuously monitors and measures the position of the original mounting stage 4. The control unit 11 controls the position and speed of the original mounting stage 4 based on the measurement results obtained from the laser interferometer.

[0025] The projection optical system 5 includes a reflector and lens (not shown), which project the pattern formed on the original plate 3 onto the substrate 6 by reflecting and refracting the exposure light. The light-shielding mechanisms 9a and 9b have driving mechanisms (not shown) that are driven in the X direction to block at least a portion of the light passing through the projection optical system 5, thereby limiting the area projected onto the substrate 6. That is, when the pattern of the original plate is transferred to the substrate by the exposure device EXP, at least a portion of the exposure light can be blocked, setting the exposure area to a desired shape. The light-shielding mechanisms 9a and 9b can be configured between the original plate and the substrate.

[0026] The substrate mounting stage 7, on which the substrate 6 is mounted, is driven in the X, Y, Z, and θ directions by a drive mechanism (not shown) under the control of the control unit 11. Multiple mirrors (not shown) are disposed on the substrate mounting stage 7 to reflect measurement light from a laser interferometer (not shown) disposed outside the substrate mounting stage 7.

[0027] The laser interferometer receives the reflected measurement light and continuously monitors and measures the position of the substrate stage 7. The control unit 11 controls the position and speed of the substrate stage 7 based on the measurement results obtained from the laser interferometer.

[0028] In the exposure apparatus EXP of this embodiment, only a pre-determined size master plate can be placed on the master plate stage 4. The size of the master plate may vary depending on the product being manufactured, which can be disadvantageous for the user of the exposure apparatus EXP in terms of cost, etc. Therefore, by using a master plate support device that can be installed as an auxiliary device for the master plate 3, exposure can be achieved even if the master plate size varies. Specifically, by using the master plate support device, a master plate smaller than that applicable to the master plate stage 4 can also be used.

[0029] Figure 2 This is a perspective view showing the structure of the original support device 20 in this embodiment. Figure 3 This is a side view showing the structure of the original plate support device 20 according to this embodiment. The original plate support device 20 has a bottom 20a that holds (supports) at least a portion of the lower surface of the original plate 3. The bottom 20a holds near the end of the original plate. The original plate support device 20 has a side portion 20b that is held by the original plate mounting stage 4 from the lower surface. By configuring the bottom 20a at a different height relative to the side portion 20b, the original plate support device 20 can maintain the same height of the original plate 3 whether the original plate support device 20 is used or not, which may be advantageous when adjusting the height position during exposure. Alternatively, the design may not be such that the height does not change at all as described above. For ease of explanation, the bottom 20a and the side portion 20b are described as separate components, but they can be interpreted as an integral part.

[0030] At least a portion of the original support device 20 may be a translucent component. For example, the original support device 20 may be as follows: Figure 3 The image shows a transmissive section 20c. This is so that when the original support device 20 is placed on the original mounting stage 4, the alignment measuring section 2 positioned above it can measure the reference mark group 8 (stage marks) set on the original mounting stage 4. Therefore, the transmissive section 20c needs to be positioned at least directly above the reference mark group 8 when the original support device 20 is placed on the original mounting stage 4. Alternatively, the entire original support device 20 can be transmissive. Additionally, the original 3 has an alignment mark group 10 (original marks).

[0031] The control unit 11 functions as a processing unit that uses the mark position information measured by the alignment measuring unit 2 to determine the driving amount of each driving mechanism during exposure.

[0032] Figure 4 This is a diagram showing an example of the configuration of the alignment marks used when using the original support device, namely the reference mark group 8 on the original mounting platform and the alignment mark group 10 on the original. Figure 4 (a) The figure shows the original mounting platform 4. Figure 4(b) The figure shows a original plate support device 20 on which the original plate 3 is placed. The original plate support device 20 is fixed to the original plate 3, which is smaller than a specified size. Reference marks 8a and 8b on the original plate mounting platform are positioned at the same locations as those used when using an original plate of a specified size. Regarding these marks, the positions in the X and Y directions with the center of the original plate mounting platform 4 as the origin are set as (XL1, YL1) and (XR1, YR1), respectively. On the original plate 3, alignment marks 10a and 10b are arranged at two points in the X direction. Regarding these marks, the positions in the X and Y directions with the center of the original plate 3 as the origin are set as (XL2, YL2) and (XR2, YR2), respectively. However, the center of the original plate mounting platform at the desired mounting position of the original plate is aligned with the center of the original plate. A transmissive portion 20c is provided on a part of the original plate support device at the position corresponding to reference marks 8a and 8b when the original plate support device 20 is mounted on the original plate mounting platform 4. The transmissive portion 20c may be glass or an unobstructed opening. Furthermore, in order to ensure that the focus adjustment amount when measuring the reference marks 8a and 8b when the original version 3 is mounted, performed by the alignment measuring unit 2, is consistent with the focus adjustment amount when measuring the same mark when the original version support device 15 is mounted, the transmission unit 20c is expected to be made of the same material and have the same thickness as the original version.

[0033] When calculating the relative position information of the mark position on the original plate after the original plate 3 is mounted on the original plate mounting stage 4 via the original plate support device 20, it is desirable, from a production volume perspective, to perform this calculation in parallel with other processes. However, the measurement light reflected by the substrate 6 and the substrate mounting stage 7 may interfere with the measurement results of the alignment measurement unit 2. For example, depending on the position and movement state of the substrate mounting stage, the measurement light transmitting the original plate mark may be reflected on the substrate or the substrate mounting stage, thereby changing the measurement conditions of the original plate's alignment mark. As a result, phenomena such as the measurement value of the original plate's alignment mark shifting or measurement failure may occur.

[0034] Therefore, in this embodiment, to prevent the measurement light from the alignment measurement unit 2 from reaching the substrate 6 and the substrate stage 7, the light-shielding mechanisms 9a and 9b are driven to block the measurement light. Normally, as explained above, the light-shielding mechanisms 9a and 9b are used to limit the exposure area during the exposure operation, so they can be positioned in a clearance position at other times. In this embodiment, during alignment measurement, the light-shielding mechanisms 9a and 9b are driven from the clearance position to a light-shielding position that blocks the measurement light from the alignment measurement unit 2. This reduces interference that could affect the measurement results of the alignment measurement unit 2. Furthermore, the driving of the light-shielding mechanisms 9a and 9b only needs to be driven in a manner that blocks at least a portion of the measurement light from the alignment measurement unit 2. Additionally, the light-shielding mechanisms 9a and 9b can have the characteristic of blocking the exposure light used in the transfer process of the exposure apparatus EXP and the measurement light generated by the alignment measurement unit 2.

[0035] Figure 5 This is a flowchart illustrating the measurement method, which describes the alignment measurement and the driving process of the light-shielding mechanisms 9a and 9b as explained above. Each step in the flowchart can be executed by controlling each part of the exposure device EXP through the control unit 11.

[0036] In step S101, the original plate mounting stage 4 and the alignment measuring unit 2 are driven in the XY directions respectively to measure reference marks 8a and 8b on the original plate mounting stage. Then, the alignment measuring unit 2 measures the reference marks 8a and 8b. When driving the original plate mounting stage 4 and the alignment measuring unit 2, if necessary, the focus adjustment mechanism of the alignment measuring unit 2 can be used to adjust the focus to match the marks on the original plate mounting stage. The measured value here represents the amount of deviation of the mark relative to the center of the field of view of the alignment measuring unit 2. The measured value of reference mark 8a is set as (dxL1, dyL1), and the measured value of reference mark 8b is set as (dxR1, dyR1).

[0037] In step S102, the light-shielding mechanisms 9a and 9b are driven to block the measurement light from the alignment measurement unit 2 (driving process). "Blocking the measurement light from the alignment measurement unit 2" means that in the measurement process of step S103 described later, the light-shielding mechanisms 9a and 9b are positioned in the optical path of the measurement light irradiated from the alignment measurement unit 2.

[0038] In step S103, the alignment measuring unit 2 is driven in the XY direction to measure the alignment marks 10a and 10b on the original plate. Then, the alignment marks 10a and 10b are measured by the alignment measuring unit 2. At this time, the light-shielding mechanisms 9a and 9b are positioned in the light-shielding position to block the measurement light in step S102, so the influence of reflected light passing through the projection optical system 5 on the measurement results can be reduced.

[0039] Furthermore, in step S103, with the center of the original mounting stage 4 as the origin, the driving position of the light-shielding mechanism 9a can be determined by XL2+OFFSET, and the driving position of 9b can be determined by XR2-OFFSET. OFFSET represents the offset amount required to completely block the light transmitted through the alignment marks 10a and 10b. From a production volume perspective, it is preferable to implement and complete the driving of the light-shielding mechanisms 9a and 9b in parallel before the end of S101 to S103.

[0040] The measurement value in step S103 represents the deviation of the mark from the center of the field of view of the alignment measuring unit 2. The measurement value of the alignment mark 10a is set as (dxL2, dyL2), and the measurement value of the alignment mark 10b is set as (dxR2, dyR2). When driving the alignment measuring unit 2, if necessary, it can also be adjusted by the focus adjustment mechanism of the alignment measuring unit 2 to match the focus with the mark on the original plate. The driving amount of the alignment measuring unit 2 in the XY direction is determined based on the relative distance from the reference mark 8a to the alignment mark 10a and from the reference mark 8b to the alignment mark 10b. The relative distance from the reference mark 8a to the alignment mark 10a can be calculated by (XL2-XL1, YL2-YL1), and the relative distance from the reference mark 8b to the alignment mark 10b can be calculated by (XR2-XR1, YR2-YR1).

[0041] In step S104, based on the measured values ​​of the marks on the original plate obtained in S103 (first measurement result) and the measured values ​​of the marks on the original plate mounting stage obtained in S101 (second measurement result), the relative position information of the marks on the original plate and the marks on the original plate mounting stage is calculated. The relative position of the reference mark 8a and the alignment mark 10a can be obtained by (dxL2-dxL1, dyL2-dyL1), and the relative position of the reference mark 8b and the alignment mark 10b can be obtained by (dxR2-dxR1, dyR2-dyR1).

[0042] Furthermore, based on the ideal relative positions of reference mark 8b and alignment mark 10b, and the calculated relative positions, the deviation between the mark positions on the original plate and the mark positions on the original plate stage is calculated. This deviation is used as a correction amount when synchronizing the original plate stage and the substrate stage during the exposure process, and can correct the relative positions of the original plate 3 and the substrate 6. Therefore, the overlay accuracy of the patterns during the exposure process can be guaranteed.

[0043] Furthermore, when the focus adjustment mechanism is driven in S101 and S103, not only is there a change in the Z direction, but the image may also shift in the X or Y direction. Therefore, the image shift in the X or Y direction when the focus adjustment mechanism in the alignment measurement unit is driven at arbitrary intervals is measured and held as a table by the data holding unit 12. Then, the image shift in the X or Y direction corresponding to the driving amount of the focus adjustment mechanism in the alignment measurement unit can be subtracted from the measurement result at the marked position on the substrate. This measurement can be performed at any timing before S101.

[0044] When the alignment measuring unit 2 is driven in the X or Y direction in S101 and S103, the actual driving position may deviate in the X or Y direction relative to the driving command value. Therefore, the amount of X or Y direction offset when the alignment measuring unit 2 is driven in the X or Y direction at arbitrary intervals is measured and stored as a table by the data holding unit 12. Then, the amount of X or Y direction offset corresponding to the driving position of the alignment measuring unit 2 can be subtracted from the mark position measurement result. This measurement can be performed at any timing before S101. In addition, S102 can be performed before the timing of the measurement in S103, for example, it can be performed before S101 or in parallel with S101 and S103. The control unit 11 controls the light-shielding mechanisms 9a and 9b, which are arranged in a position that does not block the measurement light, so that the light-shielding mechanisms 9a and 9b block the measurement light passing through the original mark when the alignment measuring unit 2 measures the original mark.

[0045] Furthermore, from a production volume perspective, when calculating the relative position information of the markings on the original substrate and the markings on the original substrate mounting stage, it is preferable to perform this calculation in parallel with other processes, for example, preferably during substrate replacement. Therefore, it is desirable that the markings on the substrate be mounted at a position overlapping with the markings on the original substrate at the substrate mounting stage position during substrate replacement.

[0046] As described above, the light-shielding mechanisms 9a and 9b are explained to have the function of blocking the exposure light during the transfer of the exposure device, but they are not limited to this and may not have the function of blocking the exposure light during the transfer. That is, the light-shielding mechanisms 9a and 9b may also be units provided for use during alignment measurement.

[0047] <Implementation Method of the Article Manufacturing Method>

[0048] The method of manufacturing articles according to the embodiments of this disclosure is suitable for manufacturing articles such as flat panel displays (FPDs), semiconductor devices, sensors, or optical components. Figure 6 This is a flowchart of the article manufacturing method according to this embodiment. The article manufacturing method of this embodiment includes a step of forming a latent image pattern on a photosensitive material coated on a substrate by exposure performed by the exposure apparatus EXP described above, thereby obtaining an exposed substrate (exposure step, step S11). It also includes a step of developing the substrate exposed in the above step to obtain a developed substrate (development step, step S12). Furthermore, the above manufacturing method includes other known processes (oxidation, film formation, vapor deposition, doping, planarization, etching, resist stripping, cutting, bonding, encapsulation, etc.) (processing step, step S13). Compared with conventional methods, the article manufacturing method of this embodiment is advantageous in at least one aspect of article performance, quality, productivity, and production cost.

[0049] The preferred embodiments of this disclosure have been described above, but this disclosure is not limited to these embodiments. It goes without saying that various modifications and alterations can be made within the scope of its spirit.

[0050] According to this disclosure, an exposure apparatus that is advantageous in measuring original markings with high precision can be provided.

[0051] While this disclosure has been described with reference to exemplary embodiments, it should be understood that this disclosure is not limited to the disclosed exemplary embodiments. The scope of the following claims should be given the broadest interpretation to cover all such modifications and equivalent structures and functions.

[0052] This application claims the benefit of Japanese Patent Application No. 2024-139590, the entire contents of which are incorporated herein by reference.

Claims

1. An exposure apparatus for transferring an original pattern onto a substrate. The exposure apparatus is characterized by having: The original mounting platform is equipped with an original support device to maintain the original version; The measuring unit illuminates the original plate mark set on the original plate with measuring light, and measures the measuring light reflected from the original plate mark; The light-shielding part blocks the measuring light; as well as The control unit controls the driving of the light-shielding part. The control unit controls the light-shielding part, which is positioned to not block the measuring light, so that when the measuring unit measures the original mark, the light-shielding part blocks the measuring light that passes through the original mark.

2. The exposure apparatus according to claim 1, characterized in that, The measuring unit further measures the measuring light reflected from the stage mark set on the original stage.

3. The exposure apparatus according to claim 2, characterized in that, It also includes a calculation unit for calculating the relative position of the original plate and the original plate mounting stage. The calculation unit calculates the relative position based on a first measurement result obtained by measuring the measurement light reflected from the original plate mark and a second measurement result obtained by measuring the measurement light reflected from the stage mark through the original plate support device.

4. The exposure apparatus according to claim 2, characterized in that, The original support device has a transmissive section that allows the measuring light to pass through.

5. The exposure apparatus according to claim 1, characterized in that, When the control unit transfers the original pattern onto the substrate using exposure light, it drives the light-shielding unit to block a portion of the exposure light.

6. The exposure apparatus according to claim 1, characterized in that, The light-shielding portion is disposed between the original plate and the substrate.

7. The exposure apparatus according to claim 1, characterized in that, The control unit moves the measuring unit to a position where it can measure the original mark, and moves the light-shielding part, which is positioned so as not to block the measuring light, so that the light-shielding part blocks the measuring light that passes through the original mark.

8. The exposure apparatus according to claim 1, characterized in that, The light-shielding part has the characteristic of blocking the exposure light and the measurement light used in the transfer process of the exposure apparatus.

9. A measurement method for measuring alignment marks in an exposure apparatus that transfers a pattern from an original plate onto a substrate. The measurement method is characterized by comprising: The driving process drives the light-shielding part to block the measuring light from the measuring part; and The measurement process involves using the measuring unit to illuminate a mark on the original plate, and then measuring the light reflected from the mark. The driving process drives the light-shielding part, which is positioned in a position that does not block the measuring light, so that when the measuring part measures the original mark, the light-shielding part blocks the measuring light that passes through the original mark.

10. A method for manufacturing an article, characterized in that, Include: The exposure process involves using the exposure apparatus described in any one of claims 1 to 8 to expose a substrate to obtain an exposed substrate; and The developing process involves developing the exposed substrate to obtain a developed substrate. Articles are manufactured from the developing substrate.

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