Exposure apparatus, exposure method, and method for producing article

Abstract

To enhance durability of an optical unit.SOLUTION: An exposure apparatus exposes a substrate with an image of a pattern of an original, and comprises: an optical element arranged in an optical path through which light from a light source passes; a plurality of drive units arranged at a plurality of locations of the optical element and configured to deform the optical element; and a control unit configured to control driving of the plurality of drive units, wherein the control unit uniformly changes initial positions of the plurality of drive units.SELECTED DRAWING: Figure 14

Description

[Technical Field]

[0001] The present invention relates to an exposure apparatus, an exposure method, and a method for manufacturing an article. [Background technology]

[0002] Exposure apparatus are known as one type of lithography equipment used in the manufacturing process of semiconductor devices, flat panel displays (FPDs), etc. Exposure apparatuses perform an exposure process in which a substrate is exposed to light through an original, thereby transferring (forming) the circuit pattern formed on the original onto the substrate.

[0003] In recent years, there has been an increase in the exposure performance required of exposure apparatuses, and in order to improve exposure performance, it is necessary to reduce the imaging error (exposure error) of the pattern in the optical system (for example, the projection optical system). For this reason, exposure apparatuses can be provided with multiple optical units (objects) for correcting the imaging error of the optical system.

[0004] Patent Document 1 discloses an exposure apparatus equipped with a high-order correction mechanism (optical unit) that can correct high-order aberrations by deforming an optical element (flat glass) using multiple actuators. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2023-162947 Summary of the Invention [Problem to be solved by the invention]

[0006] However, repeated operations of deforming the optical element using a plurality of actuators may cause wear on the actuators.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an exposure apparatus that is advantageous in terms of improving the durability of the optical unit. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, an exposure apparatus as one aspect of the present invention is an exposure apparatus that exposes an image of a pattern of an original onto a substrate, and includes an optical element arranged in an optical path through which light from a light source passes, a plurality of driving units arranged at multiple locations on the optical element and that deform the optical element, and a control unit that controls the driving of the plurality of driving units, and is characterized in that the control unit uniformly changes the initial positions of the plurality of driving units. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an exposure apparatus that is advantageous in terms of improving the durability of the optical unit. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of an exposure apparatus. [Figure 2] FIG. 2 is a schematic diagram illustrating a configuration of an optical unit. [Figure 3] FIG. 2 is a schematic diagram illustrating a configuration of an actuator. [Figure 4] FIG. 10 is a diagram showing a state in which the actuator clamps the optical element. [Figure 5] FIG. 10 is a diagram showing a state in which an actuator is deforming an optical element. [Figure 6] FIG. 10 is a diagram showing evaluation points of optical elements. [Figure 7] FIG. 2 shows an exposure area of ​​a substrate. [Figure 8] FIG. 10 is a diagram showing a state in which an exposure area is divided according to correction point numbers. [Figure 9] 4 shows a driving profile of an actuator ACT1 in the first embodiment. [Figure 10] 4 shows a driving profile of an actuator ACT2 in the first embodiment. [Figure 11] 10 shows a drive profile of the actuator ACT1 in the first embodiment after a uniform offset during exposure (after a change in the initial position). [Figure 12] 10 shows a drive profile of the actuator ACT2 in the first embodiment after a uniform offset during exposure (after a change in the initial position). [Figure 13] FIG. 10 is a diagram for explaining uniform parallel driving. [Figure 14] 4 is a flowchart of a control method for the exposure apparatus in the first embodiment. [Figure 15] 10 shows a drive profile of the actuator ACT1 in the second embodiment after a uniform offset during exposure (after changing the initial position). [Figure 16] 10 shows a drive profile of the actuator ACT2 in the second embodiment after a uniform offset during exposure (after changing the initial position). [Figure 17] 10 is a flowchart of a control method for an exposure apparatus in the second embodiment. [Figure 18] 1 is a flowchart of a method for manufacturing an article. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to designate the same components, and redundant explanations will be omitted.

[0012] First Embodiment An outline of the exposure apparatus according to this embodiment will be described below with reference to Fig. 1. Fig. 1 is a schematic diagram showing the configuration of the exposure apparatus EX. An optical unit 300 that the exposure apparatus EX according to this embodiment has will also be described with reference to Fig. 2. Fig. 2 is a schematic diagram showing the configuration of the optical unit 300.

[0013] The exposure apparatus EX has a mask stage MST that holds and moves a mask 101 (master) on which a pattern is formed, and a substrate stage PST that supports a substrate P that is coated with a photosensitive material (photoresist). The exposure apparatus EX also has an illumination optical system IL that illuminates the mask 101 with exposure light EL, and a projection optical system PL that projects and transfers the pattern of the mask 101 illuminated by the exposure light EL onto the substrate P held by the substrate stage PST.

[0014] The mask 101 held by the mask stage MST and the substrate P held by the substrate stage PST are arranged in a conjugate positional relationship via the projection optical system PL. The exposure apparatus EX in this embodiment is configured as a so-called mirror scan exposure apparatus that has a large concave mirror. The substrate P is typically a glass plate (glass substrate), but may also be a semiconductor wafer such as silicon.

[0015] In this embodiment, the exposure apparatus EX is configured as a scanning exposure apparatus, and moves the mask 101 and substrate P in synchronization with each other relative to the illumination optical system IL that emits the exposure light EL, thereby transferring the pattern of the mask 101 onto the substrate P by scanning exposure. In the following, the optical axis direction of the projection optical system PL is referred to as the Z-axis direction, the direction in which the mask 101 and substrate P move in synchronization with each other perpendicular to the Z-axis direction is referred to as the Y-axis direction (scanning direction), and the direction perpendicular to the Z-axis direction and the Y-axis direction is referred to as the X-axis direction. Furthermore, the directions around the X-axis, Y-axis, and Z-axis are referred to as the θX direction, θY direction, and θZ direction, respectively.

[0016] The illumination optical system IL includes a light source such as a high-pressure mercury lamp or an LED, an elliptical mirror that condenses the light beam emitted from the light source, and a condenser lens that expands and collimates the light beam condensed by the elliptical mirror. The illumination optical system IL further includes a limiting slit plate for defining an illumination region of a predetermined area, and a mirror that reflects the light beam from the limiting slit plate to irradiate the mask 101 with a slit-shaped illumination light beam.

[0017] The exposure light EL generated by the illumination optical system IL may be, for example, ultraviolet emission lines (g-line, h-line, i-line) emitted from a mercury lamp or an LED, KrF excimer laser light (wavelength 248 nm), ArF excimer laser light (wavelength 193 nm), etc. The illumination optical system IL is configured as a so-called Koehler illumination system.

[0018] The mask stage MST is configured to drive the mask 101 to scan relative to the illumination optical system IL, and has a long stroke in the Y-axis direction (scanning direction) and an appropriate stroke in the X-axis direction perpendicular to the scanning direction. The mask stage MST has a suction portion for holding the mask 101. The suction portion is connected to a vacuum device (not shown), and the mask 101 is held by vacuum suction by the suction portion.

[0019] As shown in FIG. 1, movable mirrors 32a and 32b are provided on the edges of the mask stage MST in the X-axis and Y-axis directions, respectively, in directions perpendicular to each other. A laser interferometer Mx1 is disposed facing movable mirror 32a, and multiple (two in this embodiment) laser interferometers My1 and My2 are disposed facing movable mirror 32b. The laser interferometers My1 and My2 irradiate movable mirror 32b with laser light to detect the distance between the laser interferometers My1 and My2 and movable mirror 32b. The detection results of the laser interferometers My1 and My2 are output to a controller C, which calculates the position of the mask stage MST in the Y-axis direction and the amount of rotation about the Z-axis based on the detection results of the laser interferometers My1 and My2. The laser interferometer Mx1 also irradiates movable mirror 32a with laser light to detect the distance between the laser interferometer Mx1 and movable mirror 32a. The detection result of the laser interferometer Mx1 is output to the control unit C, which determines the position of the mask stage MST in the X direction based on the detection result of the laser interferometer Mx1. The control unit C sets the mask stage MST to the desired position (posture) while monitoring the position (posture) of the mask stage MST from the outputs of the laser interferometers Mx1, Mx2, and My1.

[0020] The exposure light EL transmitted through the mask 101 enters the projection optical system PL. The projection optical system PL includes multiple mirrors 52 and 54 with reflective surfaces and an optical unit 300 that corrects imaging errors, and forms an image of the pattern present in the illumination area of ​​the mask 101 on the substrate P. An imaging device AS is provided above the mask 101, and light of a different wavelength than the exposure light EL typically passes through the mask 101 and projection optical system PL and is projected onto the substrate stage PST. Reflected light similarly passes through the projection optical system PL and mask 101 and is captured by the imaging device AS. The imaging device AS measures the imaging performance of the projection optical system PL. The imaging device AS may be located on the optical unit 300, in which case the imaging performance of the optical unit 300 alone is measured.

[0021] The substrate stage PST, which drives the substrate P, has a scanning stroke in the Y-axis direction (scanning direction) and a stepping stroke in the X-axis direction, which is perpendicular to the scanning direction, just like the mask stage MST. Furthermore, the substrate stage PST is configured to be movable in the Z-axis direction and the θX, θY, and θZ directions.

[0022] 1, movable mirrors 33a and 33b are installed in orthogonal directions on the edges of the substrate stage PST in the Y-axis and X-axis directions. Multiple (e.g., three) laser interferometers Px1, Px2, and Px3 are arranged to face movable mirror 33a extending in the X-axis direction. Furthermore, multiple (e.g., two) laser interferometers Py1 and Py2 are arranged to face movable mirror 33b extending in the Y-axis direction.

[0023] The multiple laser interferometers Py1, Py2 irradiate the movable mirror 33b with laser light and detect the distance between the laser interferometers Py1, Py2 and the movable mirror 33b. The detection results of the laser interferometers Py1, Py2 are output to the control unit C, which determines the position of the substrate stage PST in the Y-axis direction and the amount of rotation about the Z-axis based on the detection results of the laser interferometers Py1, Py2. In addition, the laser interferometers Px1 to Px3 irradiate the movable mirror 33a with laser light and detect the distance between the laser interferometers Px1 to Px3 and the movable mirror 33a. Here, since the substrate stage PST has a long stroke for scanning in the Y-axis direction, the laser interferometers Px1 to Px3 are switched depending on the position of the substrate stage PST.

[0024] The detection results of the laser interferometers Px1 to Px3 are output to the control unit C, which determines the position of the substrate stage PST in the X-axis direction based on the detection results of each of the laser interferometers Px1 to Px3. The control unit C monitors the position (posture) of the substrate stage PST from the outputs of the laser interferometers Py1, Py2, and Px1 to Px3, and sets the substrate stage PST to a desired position (posture).

[0025] The control unit C drives the mask 101 and the substrate P synchronously in the X-axis direction in an arbitrary scanning direction (synchronous movement speed) relative to the projection optical system PL while monitoring the positions of the mask stage MST and the substrate stage PST.

[0026] Next, an optical unit 300 according to this embodiment will be described. As shown in Fig. 2, the optical unit 300 has a configuration in which a plurality of (e.g., 24) actuators 302 (drive units) are arranged around an optical element 301. The optical unit 300 is arranged in an optical path through which light (exposure light) from a light source passes. As shown in Fig. 5, the optical unit 300 has a configuration in which the actuators 302 are independently driven to apply displacement to each position of the optical element 301, thereby deforming the optical element 301.

[0027] The optical element 301 is typically made of glass, but may be made of other materials. It is typically made of flat glass, but may be made of a material with a shape other than a flat plate, such as a cylindrical lens. Its shape is typically a sector cut from an arc, but it is not limited to this and may be rectangular or circular. When the optical element 301 is made of flat glass, it has the advantage over a non-flat glass in that the imaging performance does not change even if the optical element 301 is uniformly offset in the height direction. The optical element 301 may also be a reflecting mirror whose reflecting surface can be deformed by an actuator 302.

[0028] 3 and 4 are diagrams showing the configuration of actuator 302 of optical unit 300. Actuator 302 is a unit for driving optical element 301 in the vertical direction (Z direction). When Y slide portion 307 is driven in the Y direction, a wedge structure (described later) converts the drive in the Y direction into drive in the Z direction, and Z slide portion 306 is driven in the vertical direction (Z direction).

[0029] The configuration of actuator 302 will be described. Actuator 302 includes upper clamp 304, lower clamp 305, Z slide 306, Y slide 307, ball screw 308, coupling 309, shaft 310, light-shielding metal plate 311, photosensor 312, encoder 314, and motor 315. Upper clamp 304 and lower clamp 305 grip optical element 301 at its top and bottom. Based on a command from control unit C, each motor 315 is driven, causing shaft 310 to rotate. The rotation of shaft 310 is transmitted to ball screw 308 via coupling 309, causing the ball screw to rotate. As shown in FIG. 4 , Y slide 307 is guided in the Y direction by Y linear guide 317 at the bottom of Y slide 307. The top surface of Y slide 307 is inclined in the Y direction, and a wedge linear guide 318 is provided on the inclined surface. The wedge linear guide 318 is a mechanism that provides linear guidance along the slope of the wedge. The upper side of the wedge linear guide 318 is connected to the bottom surface of the Z slide section 306. The bottom surface of the Z slide section 306 has a slope along the Y direction and is configured to slide parallel to the upper surface of the Y slide section 307. Furthermore, the Z slide section 306 is guided in the Z direction by the Z linear guide 316. When the Y slide section 307 moves in the Y direction, the amount of overlap between the slope and the Z slide section 306 changes. As a result, when the Y slide section 307 is driven in the Y direction, the Z slide section 306 is driven in the Z direction. If the slope angle is, for example, 14°, the amount of movement in the Z direction is reduced to 1 / 4 of the amount of movement in the Y direction. The force required for driving is also reduced to 1 / 4.

[0030] When the Y slide unit 307 is driven, the encoder 314 reads the displacement in the Y direction. The encoder 314 may be either incremental or absolute. Because there is a one-to-one correspondence between the Y and Z displacements, the Z displacement can be determined by obtaining the Y displacement. For example, if the wedge tilt angle is 14° as described above, the Z displacement is 1 / 4 of the value indicated by the encoder 314. While the encoder 314 has been described as reading the Y displacement, it may also be installed to read the Z displacement. In this case, the value indicated by the encoder 314 directly corresponds to the Z displacement. The actuator 302 is driven by a command from the control unit C, and while checking the current position with the encoder 314, it is driven to the desired position. After driving, it is determined from the current position of the encoder 314 that the actuator has correctly moved to the commanded position. The commanded position is a reference position, which is the position that would be achieved if the actuator were driven ideally based on a predetermined command value.

[0031] 3, the photosensor 312 is placed at the limit of the actuator 302, and when the limit is reached during operation, the photosensor 312 detects the light-blocking metal plate 311. When the light-blocking is detected, the control unit C sends an interlock signal, and the actuator stops operating.

[0032] Next, we will explain a method for correcting imaging errors using the optical unit 300. The optical unit 300 deforms the optical element 301 by independently driving the actuators 302 in the Z direction. The drive amount of each actuator for correcting imaging errors is calculated by the control unit C. The method for calculating the drive amount is shown below.

[0033] First, the imaging sensitivity matrix for each actuator is calculated in advance. Imaging sensitivity indicates the amount of change in imaging performance at an evaluation point on the image plane when only one actuator is driven by a predetermined drive amount. Figure 6 shows an example of the position of the evaluation point. One or more evaluation points 400 are set on the optical element 301. The imaging sensitivity at these evaluation points is calculated before exposure begins with the exposure apparatus EX. Since multiple evaluation points are generally used in the optical region, imaging sensitivity is expressed as a vector. Imaging performance indicates optical parameters required to correct distortion, astigmatism, and the like. Imaging sensitivity may be calculated by simulation, or based on actual measurements obtained by measuring images with the imaging apparatus AS when each actuator is driven one by one in an actual device.

[0034] By driving each actuator sequentially with a predetermined drive amount, imaging sensitivity vectors equal to the number of actuators can be obtained, and arranging these in a matrix forms the imaging sensitivity matrix. This can be expressed as the formula below. Let m be the number of actuators, n be the number of evaluation points on the imaging plane, and Bi be the vector that represents the amount of change in imaging performance at each evaluation point when the i-th actuator is driven. Bi=[Ai1,Ai2,···,Ain](i=1,2,···,m)···(1) Here, Aij is the amount of change in imaging performance at the jth evaluation point when the i-th actuator is driven by a predetermined drive amount. Arranging these for the number of actuators results in the imaging sensitivity matrix C, C = [B1, B2, , Bm] (2) If the imaging error at the j-th evaluation point is Sj, the imaging error matrix S can be expressed as follows: S = [S1, S2, , Sm] (3) When the drive amount of the ith actuator when correcting the imaging error is Di, the drive amount matrix D is expressed as follows: D = [D1, D2, , Dn] (4) It can be expressed as:

[0035] The control unit C calculates the drive amount of each correction mechanism in the calculation unit using the received image formation error correction amount and the image formation sensitivity matrix stored in the storage unit. If the image formation error correction amount is S and the drive amount is D, the exposure error correction amount can be expressed as the product of the integrated sensitivity matrix and the drive amount. The image formation error correction amount S is expressed as follows: S = C × D (5) As mentioned above, since the imaging sensitivity matrix C is generally not a square matrix, an inverse matrix does not exist, and the drive amount D cannot be uniquely calculated from the above formula. Therefore, it is calculated using the pseudo-inverse matrix (or generalized inverse matrix) of the imaging sensitivity matrix C. When the pseudo-inverse matrix of the imaging sensitivity matrix C is pinv(C), the drive amount D is D = pinv(C) × S (6) The method of solving simultaneous equations using a pseudo-inverse matrix is ​​mathematically equivalent to the least squares method.

[0036] Changing the position and orientation of optical elements can achieve the desired imaging performance, such as correcting distortion, but astigmatism may occur. In this case, the optical elements must be deformed within a range that keeps the astigmatism that occurs as a side effect below an allowable value, which is a constraint.

[0037] Furthermore, the material that constitutes the optical element 301 is generally glass, and the greater the difference in Z direction between adjacent actuators, the greater the deformation stress, which may cause cracking if it exceeds a specified value. Therefore, the difference in command positions between adjacent actuators may be used as a constraint. Furthermore, if the drive speed exceeds a specified value, the motor 315 may lose synchronization and may not be able to drive to the commanded position, so the drive speed may also be used as a constraint.

[0038] The optical unit 300 corrects imaging errors by individually controlling each of the actuators during scanning exposure by the exposure apparatus EX in accordance with the scanning of the mask stage MST and substrate stage PST in the Y-axis direction. As shown in Figure 7, the substrate P is (virtually) divided into multiple exposure areas, and these areas are exposed in a single Y-direction scan. In the case of Figure 7, exposure areas A1 to A4 are exposed in four Y-direction scans. The above exposure areas are also called shot areas.

[0039] The exposure area further has one or multiple correction points in the Y direction, and is divided into correction areas in the Y direction according to the number of correction points. Each actuator drives the optical element 301 to the shape at each correction point, and moves at a constant speed or while accelerating and decelerating to the command position between the correction points. In the case of Figure 8, there are five correction points (correction point numbers 1 to 5), and the exposure area is (virtually) divided into four correction areas.

[0040] In the following, for ease of explanation, it is assumed that there are two actuators that grip and deform the optical element 301, and these are designated as actuators ACT1 and ACT2. The command values ​​input to actuators ACT1 and ACT2 are shown in FIGS. 9 and 10. FIG. 9 is a graph showing the command value for actuator ACT1, and FIG. 10 is a graph showing the command value for actuator ACT2. In the graphs of FIGS. 9 and 10, the vertical axis represents the drive position from the center of the stroke, and the horizontal axis represents the correction point number.

[0041] Actuator ACT1 is driven within a range of 15 to 50 μm from the stroke center position, and actuator ACT2 is driven within a range of 2 to 45 μm from the stroke center position. Each actuator repeatedly performs the same drive on exposure areas A1 to A4. Furthermore, each time substrate P is replaced, the actuators are driven in the same way.

[0042] However, when the actuator is driven as described above (for example, by repeatedly performing a predetermined operation), the sliding parts of the actuator wear locally. Examples of sliding parts include ball screw 308, Z linear guide 316, Y linear guide 317, and wedge linear guide 318 in FIG. 4. In ball screw 308, the ball rotates by rolling along the groove of the screw, causing wear on the contact surface between the ball and the groove. Furthermore, when the guide is a linear guide, the ball rolls on the rail, causing wear on the contact surface between the ball and the rail. In the case of a cross roller guide, the roller rolls on the rail, causing wear on the contact surface between the roller and the rail. While the above description deals with repeatedly performing a predetermined operation, the predetermined operation does not have to be exactly the same operation and includes driving within a similar range.

[0043] In this embodiment, to reduce localized wear of the sliding components, the stroke center positions of the actuators 302 are periodically offset uniformly for all axes. "Uniformly" means that all axes of the actuators are driven with almost no deviation, and the ratio of the deviation between adjacent actuators to the drive amount of the actuators can be within 5%. That is, the initial positions (home positions) of the actuators 302 are changed uniformly for all axes. This distributes wear and reduces localized wear. Furthermore, it is preferable that the drive range after the uniform offset does not overlap with the drive range before the uniform offset. Specifically, it is preferable that the drive range of at least one of the actuators 302 after changing the initial position of the actuators 302 does not overlap with the drive range of at least one of the actuators 302 before changing the initial position. More preferably, it is preferable that the drive range of all of the actuators 302 after changing the initial position of the actuators 302 does not overlap with the drive range of all of the actuators 302 before changing the initial position.

[0044] Therefore, it is preferable that the uniform offset amount is equal to or greater than the difference between the maximum and minimum command positions of all axes of the actuator. However, it is not an essential requirement of this embodiment that the uniform offset amount be equal to or greater than the difference between the maximum and minimum command positions of all axes, and it may be equal to or less than the difference between the maximum and minimum values.

[0045] Adding a uniform offset to the drive profiles of actuators ACT1 and ACT2 shown in Figures 9 and 10 results in drive profiles such as those shown in Figures 11 and 12. Figure 11 is a graph showing the drive profile of actuator ACT1 in this embodiment, and Figure 12 is a graph showing the drive profile of actuator ACT2 in this embodiment.

[0046] As can be seen from Figures 9 and 10, the maximum command position for all axes is 50 µm and the minimum is 2 µm. Therefore, the difference between the maximum and minimum values ​​is 50 µm - 2 µm = 48 µm, which means that an offset of 48 µm or more is possible. This uniform offset amount is added to the command position of each actuator. The uniform offset amount is calculated by control unit C, and the command position with the uniform offset amount added is sent to each actuator. In this embodiment, by uniformly offsetting the stroke center positions of the actuators and driving them as described above, wear is distributed and durability is improved.

[0047] In this embodiment, the change in the initial position of the actuator 302 is performed at a timing when the substrate P is not exposed (i.e., a timing between exposures). Also, in this embodiment, the addition of the uniform offset amount may be performed when scanning exposure has been performed a predetermined number of times, or may be performed after a predetermined period of time has elapsed. The predetermined period may be, for example, one month or one year.

[0048] Furthermore, the addition of the uniform offset amount may be performed in response to a user instruction. For example, the exposure apparatus EX may further include a user interface (console, touch panel, etc.) that accepts instructions from the user. The addition of the uniform offset amount can be performed when the user presses a "change uniform offset" button on the user interface.

[0049] According to the above method, the longer the stroke that the actuator can drive and the smaller the difference between the maximum and minimum command positions of all axes, the longer the lifespan. For example, suppose the stroke that the actuator can drive is 500 μm. If the maximum and minimum command positions of all axes are 50 μm and 2 μm, respectively, the difference is 48 μm, so the uniform offset amount is 48 μm. Since uniform offsets can be performed 500 ÷ 48 = 10 times within the stroke, the lifespan of the actuator is improved by approximately 10 times. In other words, the longer the stroke and the smaller the difference between the maximum and minimum command positions of all axes are, the better. When calculating the drive amount of each actuator to correct imaging errors in control unit C, by using the difference between the maximum and minimum command positions of all axes as a constraint, it is possible to calculate the drive amount so that the number of times uniform offsets are possible is increased.

[0050] The above describes a method for calculating the uniform offset amount so that the drive area after the uniform offset does not overlap with the drive area before the uniform offset, but this method results in areas that are never used for drive. For example, as shown above, assume that the drive stroke is 500 μm and the difference between the maximum and minimum command positions for all axes is 48 μm. In this case, a total of 10 uniform offsets are possible, so 48 x 10 = 480 μm is used for drive, and wear is distributed within this range. However, the remaining 500 - 480 = 20 μm is an area that is never used for drive. Below is shown a method for using this area for drive as well, to distribute wear more effectively.

[0051] In addition to reducing the uniform offset amount, increasing the frequency of the uniform offset minimizes the redundant area. With this method, the drive area after the uniform offset may overlap with the drive area before the uniform offset. For example, assume the stroke is 500 μm and the difference between the maximum and minimum command positions of all axes is 48 μm. If the uniform offset amount is 2 μm, then 2 μm becomes the new drive area after the uniform offset, and the remaining 46 μm overlaps with the area before the uniform offset. (500 - 48) ÷ 2 = 226, so a total of 226 uniform offsets will use the entire 500 μm of stroke. The uniform offset amount is not limited to this; a smaller amount, such as 1 μm, can also be used. In this case, the number of uniform offsets will increase, and the entire drive area will be used with (500 - 48) ÷ 1 = 502 uniform offsets. The drive area refers to the range that is not detected by the photosensor, for example. By using a smaller uniform offset amount and increasing the frequency of the uniform offset, the unused stroke is minimized, distributing wear across the entire stroke. The frequency of the uniform offset can be, for example, once a day or once a week.

[0052] If the optical element 301 is flat glass, the imaging sensitivity matrix does not change even if it is uniformly offset in the height direction, so imaging performance is not affected. In other words, even if the stroke center position is uniformly offset on all axes using the above method, the imaging performance does not change and the durability of the sliding parts can be improved.

[0053] The stroke center position may be uniformly offset after a sensor detects a change in the actuator's drive accuracy or correction performance due to wear. For example, the stroke center position may be uniformly offset when a deviation of a specified value or more occurs between the command position and the current position read by the encoder during correction drive. Furthermore, the stroke center position may also be uniformly offset when the imaging performance measured by the imaging device AS falls below a specified value.

[0054] The actuator 302 may be subject to driving errors due to dimensional errors of each component, mounting errors during assembly, preload errors, and other factors. Therefore, when the stroke center position is uniformly offset, the actuator may not be driven to the desired uniform offset position. The encoder 314 reads the current position after the uniform offset. If the deviation between the uniform offset position and the current position exceeds a specified value, the actuator performs a drive operation in a direction that reduces the deviation. Furthermore, if the change in imaging performance measured by the imaging device AS before and after the uniform offset exceeds a specified value, the actuator performs a drive operation in a direction that reduces the change. The imaging performance refers to optical aberrations such as distortion and astigmatism. When driving the motor 315 to the uniform offset position, the motor 315 may lose synchronization. The encoder 314 reads the current position or the imaging performance is measured by the imaging device AS to check whether the motor 315 has lost synchronization. If the motor 315 has lost synchronization, the drive speed is reduced to a level at which it will not lose synchronization, and the motor is driven to the uniform offset position.

[0055] If localized wear occurs in the sliding parts of the actuator, it may not drive according to commands. The difference between the current position and the commanded position is large in the area where localized wear has occurred. As a result, the drive accuracy in that area may be poor, and imaging performance may deteriorate. To drive accurately even when wear has occurred, the command value in the area where wear has occurred can be multiplied by a constant. The constant is calculated from the relationship between the command value from the main control device C and the displacement of the encoder 314 after drive. The constant can be calculated by dividing the command value by the actual displacement. For example, if the command value is 10 μm and the actual displacement is 5 μm, the constant is 2. By multiplying the command value in this area by 2, it is possible to drive while suppressing drive errors even when wear has occurred.

[0056] Lubricant is applied to the sliding parts of the actuator 302. The sliding parts are the ball screw 308, Z linear guide 316, Y linear guide 317, and wedge linear guide 318 shown in FIG. 4, and lubricant is applied between the balls or rollers and the screw grooves or rails. Applying lubricant prevents direct contact between the parts and reduces wear. Repeated driving of the actuator 302 may gradually cause the lubricant to move outside the driving range. Therefore, uniform parallel driving, which moves back and forth between the plus and minus stroke limits as shown in FIG. 13, is performed to keep the lubricant uniform. The frequency of uniform parallel driving may be, for example, every time one substrate P is exposed or once a day. The driving method does not have to be uniform, and any driving method can be used as long as the lubricant spreads. If the actuator 302 is controlled to drive beyond its driving range during scanning exposure, the lubricant will spread, so such driving is sufficient.

[0057] Next, a control method for the exposure apparatus EX in this embodiment will be described. Fig. 14 is a flowchart showing the steps of the control method. Each step of the flowchart can be controlled by the controller C.

[0058] In step S1, the drive amount of the actuator 302 to be driven during scanning exposure is calculated (calculation step). Specifically, the drive amount D is calculated from the imaging sensitivity matrix C described above.

[0059] In step S2, the substrate P is subjected to scanning exposure (exposure step). At this time, as described above, by performing exposure while deforming the optical element 301 with the actuator 302, it is possible to reduce aberration.

[0060] In step S3, it is determined whether or not the uniform offset needs to be changed (determination step). If it is necessary, the process proceeds to step S4, and if it is not necessary, the flow chart is ended.

[0061] In step S4, a uniform offset is added, that is, the initial positions of the plurality of actuators 302 are uniformly changed (changing step). This changes the driving region before and after the changing step, making it possible to reduce local wear.

[0062] As described above, in this embodiment, adding a uniform offset amount makes it possible to suppress local wear and improve the durability of the optical unit.

[0063] Second Embodiment In this embodiment, a driving method for improving the durability of the actuator 302 will be described with reference to Figures 9, 10, 15, and 16. The driving method for the actuator 302 in this embodiment is a method in which the actuator is driven while applying a uniform offset to all axes while exposing the substrate P during scanning exposure, minimizing the number of times the actuator passes the same point during its stroke, thereby dispersing wear. This means minimizing the number of times the driving direction of each actuator changes. Note that a description of the same configuration as in the first embodiment will be omitted.

[0064] The following describes a method for driving the actuators while applying a uniform offset to all axes during scanning exposure. For simplicity's sake, the optical unit 300 has two actuators, designated ACT1 and ACT2. The drive profiles for each axis are shown in Figures 9 and 10, respectively, and the number of correction points during scanning exposure in the Y direction is five. The drive profiles for actuators ACT1 and ACT2 after applying a uniform offset are shown in Figures 15 and 16. For example, the command positions for correction point number 5 are 15 μm and 30 μm for ACT1 and ACT2, respectively, with a difference of 15 μm. The command positions for correction point number 5 after the uniform offset are 75 μm and 90 μm, respectively, with a difference of 15 μm. Wear is dispersed by applying a uniform offset during scanning exposure without changing the positional relationships between the actuators, i.e., without changing the shape of the optical element 301. For example, in the case of actuator ACT1, before the uniform offset, as shown in Figure 9, the correction drive for correction points 1 to 5 passes the same location within the stroke a maximum of three times, but after the uniform offset, as shown in Figure 15, the number of passes is reduced to one (the same location is not passed more than twice). By reducing the number of passes from three to one, the wear areas are dispersed, improving durability. In the above case, the number of passes is reduced to one-third, so the lifespan is extended by approximately three times. Furthermore, if the optical element 301 is flat glass, applying a uniform offset during scanning exposure does not change the imaging performance.

[0065] Since durability improves as the number of times the actuator passes through the same point within its stroke decreases, the number of passes may be added as a constraint when calculating the drive amount. Similarly, durability improves when the number of times the drive direction changes is small, so this may also be added as a constraint.

[0066] The uniform offset amount during scanning exposure is calculated by the control unit C. The calculation method is as follows. First, the control unit C calculates the drive amount of each actuator that corrects the imaging error. The command position of the i-th actuator at correction point number k is Vik. Furthermore, if the uniform offset amount at correction point number k is Uk, and the command position of the i-th actuator at correction point number k after the uniform offset is Wik, then Wik=Vik+Uk···(7) It can be expressed as:

[0067] At correction point number 1, there is no need for a uniform offset, so U1 = 0 and Vi1 = Wi1. For correction point numbers 2 and onwards, if the number of actuators is n, the uniform offset amount Uk is given by Uk=MAX((W1k−1)−V1k,(W2k−1)−V2k,···,(Wnk−1)−Vnk)···(8) Here, the MAX() function returns the maximum value of the numbers in the parentheses.

[0068] The uniform offset amount is not limited to the above, and may be increased linearly for each correction point, for example. In this case, the uniform offset amount Uk at correction point number k is Uk=A×k, where A is a constant. Furthermore, if the constant A is equal to or greater than the maximum value of the drive amount, a drive profile is created in which the drive direction does not change, and a greater effect of dispersing wear can be expected. In other words, the constant A is, A=MAX(V1k-(V1k-1),V2k-(V2k-1),...,Vnk-(Vnk-1))...(9) It can be expressed as:

[0069] In the method using a uniform offset during scanning exposure described above, the overall drive stroke is longer, improving durability, but the drive speed required for correction also increases. The higher the drive speed, the more likely the motor 315 is to lose synchronization. Furthermore, the higher the drive speed, the greater the drive error, so the constraints on the drive speed when calculating the drive amount are typically stricter than in the method of the first embodiment.

[0070] Furthermore, during scanning exposure, the current position is constantly read by the encoder 314, and if there is a deviation between the current position and the commanded position that is greater than a specified value, this is notified to the control unit C. In this case, the control unit C changes the constraint conditions on the drive speed and calculates the drive amount again. The drive is performed using a new drive profile with the changed drive speed, and the current position is constantly read by the encoder 314 during scanning exposure. If there is a deviation between the current position and the commanded position that is greater than a specified value, the constraint conditions on the drive speed are further changed and the drive amount is calculated. Thereafter, similar calculations are repeated to determine the drive amount.

[0071] The above describes a method in which the encoder 314 reads the current position during scanning exposure and measures the deviation from the commanded position, but a method in which the imaging performance is measured during scanning exposure by the imaging device C and compared with a target value may also be used. If the deviation from the target value of the imaging performance is equal to or greater than a specified value, the constraint conditions for the drive speed are changed and the drive amount is calculated again.

[0072] Next, a control method for the exposure apparatus EX in this embodiment will be described. Fig. 17 is a flowchart showing each step of the control method. Each step of the flowchart can be controlled by the controller C.

[0073] In step S5, the drive amount of the actuator 302 to be driven during scanning exposure is calculated (calculation step). Specifically, the drive amount D is calculated from the imaging sensitivity matrix C described above.

[0074] In step S6, the substrate P is subjected to scanning exposure (exposure step). At this time, as described above, by performing exposure while deforming the optical element 301 with the actuator 302, it is possible to reduce aberration.

[0075] In step S7, it is determined whether or not the uniform offset needs to be changed (determination step). If it is necessary, the process proceeds to step S8, and if it is not necessary, the flow chart is ended.

[0076] In step S8, a uniform offset is added, that is, the initial positions of the plurality of actuators 302 are uniformly changed (change step). Thereby, the drive region is changed before and after the change step, and local wear can be reduced. In the present embodiment, steps S6, S7, and S8 are performed in parallel, that is, it is different from the first embodiment in that the change of the initial position is executed during the scanning exposure. Also, step S7 may be performed not in parallel with step S6 but before step S6 is executed.

[0077] As described above, in the present embodiment, by adding a uniform offset amount during the scanning exposure, local wear can be suppressed, and the durability of the optical unit can be improved.

[0078] <Third Embodiment> In the present embodiment, in the step of calculating the driving amount of the actuator, by adding a constraint condition in the driving direction during the scanning exposure, the number of times passing through the same location during the stroke is minimized, and wear is dispersed. The method of adding a constraint condition to the driving direction is shown below.

[0079] When the command position at the correction point number k of the i-th actuator is Wik, Wik < Wi(k + 1) is satisfied. For example, when the number of correction points is 5, for all actuators, Wi1 < Wi2 < ··· < Wi5 holds. By adding this constraint condition to the step of calculating the driving amount for correcting the imaging error, the actuator does not reverse the drive during the scanning exposure and drives uniformly in the same direction. For example, in the exposure region with 5 correction points, when there is no constraint condition in the driving direction, the driving direction reverses up to 3 times at most. The number of times passing through the same location within the stroke is 4 times. When a constraint condition of driving uniformly in the same direction is added, the driving direction does not reverse, and the same location is passed through only once. Therefore, the durability is improved by 4 times compared to the case without the constraint condition. In the case of Wi1 < Wi < ··· < Wi5, it drives uniformly vertically upward, but a constraint condition may be added so that it drives uniformly downward, and in that case, Wi1 > Wi2 > ··· > Wi5.

[0080] That is, in this embodiment, the control unit C drives the plurality of driving units while exposing the substrate so that the driving direction of each of the plurality of driving units does not change while the substrate is being exposed.

[0081] Also, it is not necessary to drive in the same direction across the entire exposure area, but it may be possible to drive in the same direction across only a certain correction point. <Wi2 <wi3>For example, Wi4>Wi5, correction points 1 to 2 are driven uniformly in the vertically upward direction, but correction points 3 to 5 can be driven uniformly in the vertically downward direction. This increases the number of times the same point is passed twice, but shortens the overall stroke, increasing the margin before contacting the limit. Also, constraints on the drive direction and changes to the initial position can be combined.

[0082] <Embodiments of manufacturing methods of articles> The method for manufacturing an article according to an embodiment of the present invention is suitable for manufacturing articles such as flat panel displays (FPDs), semiconductor devices, sensors, and optical elements. FIG. 18 is a flowchart of the method for manufacturing an article according to this embodiment. The method for manufacturing an article according to this embodiment includes a step of forming a latent image pattern on a photosensitive material coated on a substrate by exposure using the exposure apparatus EX to obtain an exposed substrate (exposure step, step S11). It also includes a step of developing the substrate exposed in this step to obtain a developed substrate (development step, step S12). Furthermore, this manufacturing method includes other well-known steps (oxidation, film formation, vapor deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, etc.) (processing step, step S13). The method for manufacturing an article according to this embodiment is advantageous over conventional methods in at least one of the performance, quality, productivity, and production cost of the article.

[0083] Although the preferred embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention.

[0084] The disclosure of the present specification includes at least the following exposure apparatus, exposure method, and method for manufacturing an article.

[0085] (Item 1) An exposure apparatus that exposes an image of a pattern of an original onto a substrate, an optical element disposed in an optical path through which light from the light source passes; a plurality of driving units arranged at a plurality of locations on the optical element and configured to deform the optical element; a control unit that controls the driving of the plurality of driving units, The exposure apparatus is characterized in that the control unit changes the initial positions of the plurality of drive units uniformly.

[0086] (Item 2) The exposure apparatus described in item 1, characterized in that the control unit changes the initial position so that the range in which at least one of the multiple drive units drives after changing the initial position does not overlap with the range in which at least one of the multiple drive units drives before changing the initial position.

[0087] (Item 3) 3. The exposure apparatus according to item 2, wherein the control unit changes the initial position so that the range in which all of the plurality of drive units drive after changing the initial position does not overlap with the range in which all of the plurality of drive units drive before changing the initial position.

[0088] (Item 4) 4. The exposure apparatus according to any one of items 1 to 3, wherein the control unit changes the initial position at a timing when the substrate is not being exposed.

[0089] (Item 5) further comprising a user interface for receiving instructions from a user; 5. The exposure apparatus according to any one of items 1 to 4, wherein the control unit changes the initial position based on the instruction.

[0090] (Item 6) further comprising an encoder for measuring the positions of the plurality of drive units; 6. The exposure apparatus according to any one of items 1 to 5, wherein the control unit controls the plurality of drive units so that the positions of the plurality of drive units measured by the encoder become reference positions.

[0091] (Item 7) 7. The exposure apparatus according to any one of items 1 to 6, wherein the control unit individually controls each of the plurality of drive units while exposing the substrate.

[0092] (Item 8) 8. The exposure apparatus according to any one of items 1 to 7, wherein the optical element includes a flat glass plate.

[0093] (Item 9) 8. The exposure apparatus according to any one of items 1 to 7, wherein the optical element includes a reflecting mirror.

[0094] (Item 10) An exposure apparatus that exposes an image of a pattern of an original onto a substrate, an optical element disposed in an optical path through which light from the light source passes; a plurality of driving units arranged at a plurality of locations on the optical element and configured to deform the optical element; a control unit that controls the driving of the plurality of driving units, The exposure apparatus is characterized in that the control unit uniformly changes the initial positions of the plurality of drive units while exposing the substrate.

[0095] (Item 11) 11. The exposure apparatus according to item 10, wherein the optical element includes a flat glass plate.

[0096] (Item 12) 11. The exposure apparatus according to item 10, wherein the optical element includes a reflecting mirror.

[0097] (Item 13) An exposure apparatus that exposes an image of a pattern of an original onto a substrate, an optical element disposed in an optical path through which light from the light source passes; a plurality of driving units arranged at a plurality of locations on the optical element and configured to deform the optical element; a control unit that controls the driving of the plurality of driving units, an exposure apparatus, wherein the control unit drives the plurality of drive units while exposing the substrate so that the direction in which each of the plurality of drive units drives does not switch while the substrate is being exposed;

[0098] (Item 14) Item 14. The exposure apparatus according to item 13, wherein the optical element includes a flat glass plate.

[0099] (Item 15) Item 14. The exposure apparatus according to item 13, wherein the optical element includes a reflecting mirror.

[0100] (Item 16) 1. A control method for controlling an exposure apparatus that exposes an image of a pattern of an original onto a substrate, comprising: an exposure step of exposing the substrate while controlling the driving of a plurality of driving units that are arranged at a plurality of locations on an optical element that is arranged on an optical path through which light from a light source passes and that deform the optical element; a changing step of uniformly changing the initial positions of the plurality of drive units; A control method comprising:

[0101] (Item 17) Item 17. The control method according to item 16, wherein the change step changes the initial position so that a range in which at least one of the plurality of drive units drives after the change step does not overlap with a range in which at least one of the plurality of drive units drives before the change step.

[0102] (Item 18) 18. The control method according to item 16 or 17, wherein the changing step is performed at a timing when the substrate is not exposed.

[0103] (Item 19) 1. A control method for controlling an exposure apparatus that exposes an image of a pattern of an original onto a substrate, comprising: an exposure step of exposing the substrate while controlling the driving of a plurality of driving units that are arranged at a plurality of locations on an optical element that is arranged on an optical path through which light from a light source passes and that deform the optical element; a changing step of uniformly changing the initial positions of the plurality of driving units while performing the exposure step; A control method comprising:

[0104] (Item 20) an exposure step of exposing a substrate using the exposure apparatus according to any one of items 1 to 15 to obtain an exposed substrate; a developing step of developing the exposed substrate to obtain a developed substrate, A method for manufacturing an article, comprising manufacturing an article from the developed substrate. [Explanation of symbols]

[0105] 101 Mask (original) 301 Optical Elements 302 Actuator (drive unit) C control section EX exposure equipment P board

Claims

1. An exposure apparatus that exposes an image of a pattern of an original onto a substrate, an optical element disposed in an optical path through which light from the light source passes; a plurality of driving units arranged at a plurality of locations on the optical element and configured to deform the optical element; a control unit that controls the driving of the plurality of driving units, The exposure apparatus is characterized in that the control unit changes the initial positions of the plurality of drive units uniformly.

2. 2. The exposure apparatus according to claim 1, wherein the control unit changes the initial position so that the range in which at least one of the plurality of drive units drives after changing the initial position does not overlap with the range in which at least one of the plurality of drive units drives before changing the initial position.

3. 3. The exposure apparatus according to claim 2, wherein the control unit changes the initial positions so that the range in which all of the plurality of drive units drive after changing the initial positions does not overlap with the range in which all of the plurality of drive units drive before changing the initial positions.

4. 2. The exposure apparatus according to claim 1, wherein the control unit changes the initial position at a timing when the substrate is not being exposed.

5. further comprising a user interface for receiving instructions from a user; 2. The exposure apparatus according to claim 1, wherein the control unit changes the initial position based on the instruction.

6. further comprising an encoder for measuring the positions of the plurality of drive units; 2. The exposure apparatus according to claim 1, wherein the control unit controls the plurality of drive units so that the positions of the plurality of drive units measured by the encoder become reference positions.

7. 2. The exposure apparatus according to claim 1, wherein the control unit controls each of the plurality of drive units individually while exposing the substrate.

8. 2. The exposure apparatus of claim 1, wherein the optical element includes a flat glass plate.

9. 2. The exposure apparatus according to claim 1, wherein the optical element includes a reflecting mirror.

10. An exposure apparatus that exposes an image of a pattern of an original onto a substrate, an optical element disposed in an optical path through which light from the light source passes; a plurality of driving units arranged at a plurality of locations on the optical element and configured to deform the optical element; a control unit that controls the driving of the plurality of driving units, The exposure apparatus is characterized in that the control unit uniformly changes the initial positions of the plurality of drive units while exposing the substrate.

11. 11. The exposure apparatus of claim 10, wherein the optical element includes a flat glass plate.

12. 11. The exposure apparatus according to claim 10, wherein the optical element includes a reflecting mirror.

13. An exposure apparatus that exposes an image of a pattern of an original onto a substrate, an optical element disposed in an optical path through which light from the light source passes; a plurality of driving units arranged at a plurality of locations on the optical element and configured to deform the optical element; a control unit that controls the driving of the plurality of driving units, an exposure apparatus, wherein the control unit drives the plurality of drive units while exposing the substrate so that the direction in which each of the plurality of drive units drives does not switch while the substrate is being exposed;

14. 14. The exposure apparatus of claim 13, wherein the optical element includes a flat glass plate.

15. 14. The exposure apparatus according to claim 13, wherein the optical element includes a reflecting mirror.

16. 1. A control method for controlling an exposure apparatus that exposes an image of a pattern of an original onto a substrate, comprising: an exposure step of exposing the substrate while controlling the driving of a plurality of driving units that are arranged at a plurality of locations on an optical element that is arranged on an optical path through which light from a light source passes and that deform the optical element; a changing step of uniformly changing the initial positions of the plurality of drive units; A control method comprising:

17. The control method according to claim 16, characterized in that the change step changes the initial position so that a range in which at least one of the plurality of drive units drives after the change step does not overlap a range in which at least one of the plurality of drive units drives before the change step.

18. 17. The control method according to claim 16, wherein the changing step is performed at a timing when the substrate is not exposed.

19. 1. A control method for controlling an exposure apparatus that exposes an image of a pattern of an original onto a substrate, comprising: an exposure step of exposing the substrate while controlling the driving of a plurality of driving units that are arranged at a plurality of locations on an optical element that is arranged on an optical path through which light from a light source passes and that deform the optical element; a changing step of uniformly changing the initial positions of the plurality of driving units while performing the exposure step; A control method comprising:

20. an exposure step of exposing a substrate using the exposure apparatus according to any one of claims 1 to 10 to obtain an exposed substrate; a developing step of developing the exposed substrate to obtain a developed substrate, A method for manufacturing an article, comprising manufacturing an article from the developed substrate.

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