Exposure apparatus, exposure method, and method for manufacturing article

Abstract

The invention relates to an exposure apparatus, an exposure method, and a method of manufacturing an article to improve durability of an optical unit. An exposure device for exposing an image of a pattern of an original plate to a substrate, the exposure device comprising an optical element disposed in an optical path through which light from a light source passes, a plurality of driving units disposed in a plurality of locations of the optical element and deforming the optical element, and a control unit for controlling the driving of the plurality of driving units, the control unit changes the initial positions of the plurality of drive units so as to coincide with each other.

Description

TECHNICAL FIELD

[0001] The present application relates to an exposure apparatus, an exposure method, and a method of manufacturing an article. BACKGROUND

[0002] As one of photolithography apparatuses utilized in a manufacturing process of a semiconductor device, a flat panel display (FPD), or the like, an exposure apparatus is known. The exposure apparatus is an apparatus that performs an exposure process of transferring (forming) a circuit pattern formed on a master to a substrate by exposing the substrate through the master.

[0003] In recent years, the requirement for exposure performance of the exposure apparatus is becoming higher, and in order to improve the exposure performance, it is sought to reduce an imaging error (exposure error) of a pattern in an optical system (for example, a projection optical system). Therefore, in the exposure apparatus, a plurality of optical units (objects) for correcting the imaging error of the optical system can be provided.

[0004] In Patent Literature 1, contents related to an exposure apparatus provided with a high-order correction mechanism (optical unit) capable of correcting a high-order aberration by deforming an optical element (flat glass) using a plurality of actuators are disclosed.

[0005] Patent Literature

[0006] Patent Literature 1: Japanese Patent Application Laid-Open No. 2023-162947 SUMMARY

[0007] Problems to be Solved by the Invention

[0008] However, since the operation of deforming the optical element using the plurality of actuators is repeated, there is a risk that the plurality of actuators are worn out.

[0009] Therefore, an object of the present application is to provide an exposure apparatus that is advantageous in improving the durability of an optical unit.

[0010] Technical Solution to Solve the Problem

[0011] In order to achieve the above object, an exposure apparatus according to one aspect of the present application is an exposure apparatus that exposes an image of a pattern of a master to a substrate, characterized by having an optical element disposed in an optical path through which light from a light source passes, a plurality of driving portions disposed at a plurality of positions of the optical element and deforming the optical element, and a control portion that controls driving of the plurality of driving portions, the control portion changing the initial positions of the plurality of driving portions in unison.

[0012] Other features of the present application will become apparent from the following description of exemplary embodiments (with reference to the accompanying drawings). BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a schematic view showing the structure of an exposure apparatus.

[0014] Figure 2 is a schematic view showing the structure of an optical unit.

[0015] Figure 3 is a schematic view showing the structure of an actuator.

[0016] Figure 4 is a view showing a state where the actuator holds the optical element.

[0017] Figure 5 is a view showing a state where the actuator deforms the optical element.

[0018] Figure 6 is a view showing an evaluation point of the optical element.

[0019] Figure 7 is a view showing an exposure area of a substrate.

[0020] Figure 8 is a view showing a state where the exposure area is divided for each correction point number.

[0021] Figure 9 is a drive distribution of the actuator ACT1 in the first embodiment.

[0022] Figure 10 is a drive distribution of the actuator ACT2 in the first embodiment.

[0023] Figure 11 is a drive distribution of the actuator ACT1 in the first embodiment after the exposure-in-common shift (after the initial position is changed).

[0024] Figure 12 is a drive distribution of the actuator ACT2 in the first embodiment after the exposure-in-common shift (after the initial position is changed).

[0025] Figure 13 is a view for explaining the in-common parallel driving.

[0026] Figure 14 is a flowchart of a control method of the exposure apparatus in the first embodiment.

[0027] Figure 15 is a drive distribution of the actuator ACT1 in the second embodiment after the exposure-in-common shift (after the initial position is changed).

[0028] Figure 16 is a drive distribution of the actuator ACT2 in the second embodiment after the exposure-in-common shift (after the initial position is changed).

[0029] Figure 17 is a flowchart of a control method of the exposure apparatus in the second embodiment.

[0030] Figure 18 is a flowchart of a manufacturing method of an article.

[0031] (Symbol Explanation)

[0032] 101: mask (reticle); 301: optical element; 302: actuator (driving section); C: control section; EX: exposure apparatus; P: substrate. DETAILED DESCRIPTION

[0033] Hereinafter, preferred embodiments of the present application will be explained in detail based on the accompanying drawings. In addition, in each drawing, the same parts are designated by the same reference numerals, and overlapping explanations will be omitted.

[0034] <First Embodiment>

[0035] Hereinafter, an outline of the exposure apparatus in the present embodiment will be explained with reference to Figure 1 Figure 1 is a schematic view showing the structure of the exposure apparatus EX. In addition, with reference to Figure 2 , the optical unit 300 that the exposure apparatus EX of the present embodiment has will be explained. Figure 2 is a schematic view showing the structure of the optical unit 300.

[0036] The exposure apparatus EX has a mask stage MST that holds and moves a mask 101 (reticle) on which a pattern is formed, and a substrate stage PST that supports a substrate P on which a photosensitive material (resist) is applied. In addition, the exposure apparatus EX 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 with the exposure light EL to the substrate P held on the substrate stage PST.

[0037] The mask 101 held on the mask stage MST and the substrate P held on the substrate stage PST are arranged in a conjugate positional relationship across the projection optical system PL. The exposure apparatus EX of the present embodiment is configured as a so-called mirror scanning type exposure apparatus having a large concave mirror. Typically, the substrate P can be a glass plate (glass substrate), but can also be a semiconductor wafer of silicon or the like.

[0038] ​In the present embodiment, the exposure apparatus EX is configured as a scanning exposure apparatus, and the mask 101 and the substrate P are moved in synchronization with each other with respect to the illumination optical system IL that emits exposure light EL, and the pattern of the mask 101 is transferred to the substrate P by scanning exposure. Hereinafter, the direction of the optical axis of the projection optical system PL is set as the Z-axis direction, the direction perpendicular to the Z-axis direction and the direction of the synchronized movement of the mask 101 and the substrate P is set as the Y-axis direction (scanning direction), and the direction orthogonal to the Z-axis direction and the Y-axis direction is set as the X-axis direction. Further, the respective directions around the X-axis, around the Y-axis, and around the Z-axis are set as the θX direction, the θY direction, and the θZ direction.

[0039] The illumination optical system IL has, for example, a light source including a high-pressure mercury lamp or an LED, an elliptical mirror that condenses a light beam emitted from the light source, and a condenser lens that enlarges and parallelizes the light beam condensed by the elliptical mirror. The illumination optical system IL also includes a limiting slit plate for defining an illumination area of a predetermined area and a mirror that reflects the light beam from the limiting slit plate and irradiates a slit-shaped illumination light beam to the mask 101.

[0040] As the exposure light EL generated by the illumination optical system IL, for example, in addition to bright lines (g-line, h-line, i-line) in the ultraviolet region emitted from a mercury lamp, an LED, or the like, a KrF excimer laser (wavelength 248 nm), an ArF excimer laser (wavelength 193 nm), or the like is used. The illumination optical system IL is configured as a so-called Kohler illumination system.

[0041] The mask stage MST is configured to perform scanning drive of the mask 101 with respect 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 orthogonal to the scanning direction. The mask stage MST has an adsorption portion for holding the mask 101. The adsorption portion is connected to a vacuum device not shown, and the mask 101 is vacuum-adsorbed and held by the adsorption portion.

[0042] As Figure 1As shown, at the end edges of the X-axis direction and the Y-axis direction on the mask stage MST, moving mirrors 32a, 32b are provided in orthogonal directions. A laser interferometer Mxl is disposed in opposition to the moving mirror 32a, and a plurality of (two in this embodiment) laser interferometers Myl, My2 are disposed in opposition to the moving mirror 32b. The laser interferometers Myl, My2 irradiate laser light to the moving mirror 32b, and detect the distance from the laser interferometers Myl, My2 to the moving mirror 32b. The detection results of the laser interferometers Myl, My2 are output to the control section C, and the control section C calculates the position of the mask stage MST in the Y-axis direction and the amount of rotation around the Z-axis based on the detection results of the laser interferometers Myl, My2. In addition, the laser interferometer Mxl irradiates laser light to the moving mirror 32a, and detects the distance from the laser interferometer Mxl to the moving mirror 32a. The detection result of the laser interferometer Mxl is output to the control section C, and the control section C determines the position of the mask stage MST in the X-axis direction based on the detection result of the laser interferometer Mxl. The control section C sets the mask stage MST to a desired position (attitude) while monitoring the position (attitude) of the mask stage MST based on the outputs of the laser interferometers Mxl, Mx2, and Myl.

[0043] Exposure light EL that has passed through the mask 101 is incident on the projection optical system PL. The projection optical system PL includes a plurality of mirrors 52, 54 having reflecting surfaces and an optical unit 300 that corrects imaging errors, and forms an image of a pattern present in an illumination area of the mask 101 on the substrate P. A camera AS is provided on the upper portion of the mask 101, and typically, light having a wavelength different from that of the exposure light EL passes through the mask 101 and the projection optical system PL, and is projected onto the substrate stage PST. The reflected light also passes through the projection optical system PL and the mask 101, and is photographed with the camera AS. The camera AS measures the imaging performance of the projection optical system PL. The position of the camera AS can also be on the optical unit 300, in which case the imaging performance of the optical unit 300 alone is measured.

[0044] The substrate stage PST that drives the substrate P has a stroke for scanning in the Y-axis direction (scanning direction), and a stroke for stepping in the X-axis direction orthogonal to the scanning direction, like the mask stage MST. Further, the substrate stage PST is configured to be movable also in the Z-axis direction and the θX, θY, θZ directions.

[0045] As Figure 1As shown, at the end edges of the Y-axis direction and the X-axis direction on the substrate stage PST, moving mirrors 33a, 33b are provided in orthogonal directions. In opposition to the moving mirror 33a extending in the X-axis direction, a plurality of (for example, 3) laser interferometers Px1, Px2, Px3 are arranged. In addition, in opposition to the moving mirror 33b extending in the Y-axis direction, a plurality of (for example, 2) laser interferometers Py1, Py2 are arranged.

[0046] The plurality of laser interferometers Py1, Py2 irradiate laser light to the moving mirror 33b, and detect the distance of the laser interferometers Py1, Py2 from the moving mirror 33b. The detection results of the laser interferometers Py1, Py2 are output to the control section C, and the control section C calculates the position of the substrate stage PST in the Y-axis direction and the rotation amount around the Z-axis based on the detection results of the laser interferometers Py1, Py2. In addition, the laser interferometers Px1 to Px3 irradiate laser light to the moving mirror 33a, and detect the distance of the laser interferometers Px1 to Px3 from the moving mirror 33a. Here, the substrate stage PST has a long stroke for scanning in the Y-axis direction, so the laser interferometers Px1 to Px3 are switched according to the position of the substrate stage PST.

[0047] The detection results of the laser interferometers Px1 to Px3 are output to the control section C, and the control section C calculates the position of the substrate stage PST in the X-axis direction based on the detection results of the laser interferometers Px1 to Px3. The control section C monitors the position (attitude) of the substrate stage PST based on the outputs of the laser interferometers Py1, Py2 and Px1 to Px3, and sets the substrate stage PST to a desired position (attitude).

[0048] The control section C monitors the positions of the mask stage MST and the substrate stage PST, and causes the mask 101 and the substrate P to be synchronously driven in the X-axis direction at a synchronous moving speed in an arbitrary scanning direction with respect to the projection optical system PL.

[0049] Next, the optical unit 300 of the present embodiment will be described. The optical unit 300 is configured as shown in FIG. 3A, for example. Figure 2 A plurality of (for example, 24) actuators 302 (driving sections) are arranged around the periphery of the 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. 3B, the optical unit 300 is configured so that the optical element 301 is deformed by driving the actuators 302 independently, thereby providing displacement to each position of the optical element 301. Figure 5

[0050] ​Typically, the optical element 301 is glass, but can be other members. Also, typically, it is a flat glass, but can be a member of a shape other than flat, such as a cylindrical lens. Also, typically, the shape is a sector cut from a circular arc, but is not limited thereto, and can be rectangular, circular. In the case where the optical element 301 is a flat glass, the imaging performance does not change even if the optical element 301 is uniformly shifted in the height direction, compared to the case where it is not a flat glass, which is advantageous in this respect. Also, the optical element 301 can be a mirror that can deform the reflecting surface by the actuator 302.

[0051] Figure 3 and Figure 4 is a diagram showing the structure of the actuator 302 of the optical unit 300.

[0052] The actuator 302 is a unit for driving the optical element 301 in the up-down direction (Z direction). It is a mechanism that, if the Y slide portion 307 is driven in the Y direction, the driving in the Y direction is converted into driving in the Z direction by the wedge-shaped configuration described later, and the Z slide portion 306 is driven in the up-down direction (Z direction).

[0053] The structure of the actuator 302 is described. The actuator 302 has a clamping upper portion 304, a clamping lower portion 305, a Z slide portion 306, a Y slide portion 307, a ball screw 308, a coupling 309, a shaft 310, a light shielding metal plate 311, a light sensor 312, an encoder 314, and a motor 315. The optical element 301 is gripped by the upper surface and the lower surface of the clamping upper portion 304 and the clamping lower portion 305. Based on the command from the control section C, each motor 315 is driven, and the shaft 310 is rotated. The rotation of the shaft 310 is transmitted to the ball screw 308 through the coupling 309, and the ball screw is rotated. As Figure 4As shown, the Y-sliding part 307 is guided in the Y direction by the Y-direction guide 317 at its bottom. The upper surface of the Y-sliding part 307 is inclined along the Y direction, and a wedge-shaped direction guide 318 is provided on the inclined surface. The wedge-shaped direction guide 318 is a mechanism that provides linear guidance along the inclined surface of the wedge. The upper side of the wedge-shaped direction guide 318 is connected to the bottom surface of the Z-sliding part 306. The bottom surface of the Z-sliding part 306 has an inclined surface along the Y direction, forming a structure that slides parallel to the upper surface of the Y-sliding part 307. Furthermore, the Z-sliding part 306 is guided in the Z direction by the Z-direction guide 316. If the Y-sliding part 307 moves in the Y direction, the amount of overlap of the inclined surface between it and the Z-sliding part 306 changes. As a result, if the Y-sliding part 307 is driven in the Y direction, the Z-sliding part 306 is driven in the Z direction. With an inclination angle of, 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.

[0054] If the Y-slider 307 is driven, the encoder 314 reads the displacement in the Y direction. The encoder 314 can be either incremental or absolute. The displacement in the Y direction corresponds one-to-one with the displacement in the Z direction, so by obtaining the displacement in the Y direction, the displacement in the Z direction can be determined. For example, if the inclination angle of the wedge is 14° as described above, 1 / 4 of the value indicated by the encoder 314 is the displacement in the Z direction. The case where the encoder 314 reads the displacement in the Y direction has been described, but it is not limited to this; it can also be installed to read the displacement in the Z direction. In this case, the value indicated by the encoder 314 remains the displacement in the Z direction. The actuator 302 is driven according to the command from the control unit C, and while confirming the current position through the encoder 314, it tracks and drives to the desired position. After driving, it is determined whether the current position of the encoder 314 has been correctly reached the commanded position. The commanded position refers to the position, i.e., the reference position, when the drive is ideally performed based on the drive based on a predetermined command value.

[0055] like Figure 3 As shown, the light sensor 312 is positioned within the limit of the actuator 302. When the limit is reached during operation, the light sensor 312 detects the light-blocking metal plate 311. If light blocking is detected, the control unit C sends an interlock signal, and the actuator stops operating.

[0056] Next, the method for correcting imaging errors using the optical unit 300 will be explained. The optical unit 300 deforms the optical element 301 by independently driving the actuator 302 in the Z direction. The driving amount of each actuator used to correct imaging errors is calculated by the control unit C. The method for calculating the driving amount is shown in the following description.

[0057] First, the imaging sensitivity matrix of each actuator is obtained in advance. The imaging sensitivity indicates the amount of change in the imaging performance at the evaluation point on the image plane when only 1 actuator is driven by a predetermined drive amount. In Figure 6 An example of the position of the evaluation point is shown in FIG. 4. The evaluation point 400 is set on the optical element 301 in a plurality or 1. The imaging sensitivity at these evaluation points is obtained before the exposure by the exposure apparatus EX is started. Since a plurality of evaluation points are generally used in the optical region, the imaging sensitivity is a vector. The imaging performance indicates the optical index required for correction of distortion aberration, astigmatism, and the like. The imaging sensitivity can be obtained by simulation or based on the measured values of the image measured by the imaging device AS in the actual machine when each actuator is driven one by one.

[0058] Each actuator is driven by sequentially driving by the determined drive amount, thereby obtaining the number of imaging sensitivity vectors corresponding to the number of actuators, which are arranged and collected into a matrix to become the imaging sensitivity matrix. If expressed in a formula, it is as follows. If the number of actuators is set to m, the number of evaluation points on the imaging plane is set to n, and the vector indicating the amount of change in the imaging performance at each evaluation point when the i-th actuator is driven is set to Bi, it can be expressed as

[0059] Bi = [Ai1, Ai2,..., Ain] (i = 1, 2,..., m)... (1).

[0060] Here, Aij is the amount of change in the imaging performance of the j-th evaluation point when the i-th actuator is driven by the determined drive amount. The matrix obtained by arranging it by the number of actuators becomes the imaging sensitivity matrix C, which can be expressed as

[0061] C = [B1, B2,..., Bm]... (2).

[0062] If the imaging error at the j-th evaluation point is set to Sj, the imaging error matrix S can be expressed as

[0063] S = [S1, S2,..., Sm]... (3).

[0064] If the drive amount of the i-th actuator at the time of correction of the imaging error is set to Di, the drive amount matrix D can be expressed as

[0065] D = [D1, D2,..., Dn]... (4).

[0066] The control section C calculates the driving amount of each correction mechanism using the transmitted imaging error correction amount and the imaging sensitivity matrix built in the storage section in the arithmetic section. If the imaging error correction amount is denoted by S and the driving amount is denoted by D, the exposure error correction amount can be expressed as the product of the comprehensive sensitivity matrix and the driving amount, and the imaging error correction amount S can be expressed as

[0067] S = C x D... (5).

[0068] As described above, generally, C as the imaging sensitivity matrix is not a square matrix, and therefore, there is no inverse matrix, and the driving amount D cannot be uniquely calculated from the above equation. Therefore, the pseudo inverse matrix (or the generalized inverse matrix) of C as the imaging sensitivity matrix is used for the calculation. If the pseudo inverse matrix of the imaging sensitivity matrix C is denoted by pinv(C), the driving amount D can be expressed as

[0069] D = pinv(C) x S... (6).

[0070] Further, the solution of the simultaneous equations based on the pseudo inverse matrix is mathematically equivalent to the least square method.

[0071] By changing the position and posture of the optical element, it is possible to correct the desired imaging performance, such as distortion aberration, but sometimes coma is generated. In this case, it is necessary to deform the optical element within a range in which the coma generated as a side effect is below the allowable value, which is a constraint condition.

[0072] In addition, the components constituting the optical element 301 are generally glass, and the greater the difference in the Z direction of the adjacent actuators, the greater the deformation stress, and if it exceeds a predetermined value, it is likely to be broken. Therefore, the difference in the command position of the adjacent actuators can also be used as a constraint condition. In addition, in the case where the driving speed is above a predetermined value, it is likely that the motor 315 will be out of step and cannot be driven to the command position, and therefore, the driving speed can also be used as a constraint condition.

[0073] The optical unit 300 controls the actuators individually during the scanning exposure process of the exposure apparatus EX in the Y-axis direction in synchronization with the scanning of the mask stage MST and the substrate stage PST, and thereby corrects the imaging error. As shown in FIG. 2, the substrate P is virtually divided into a plurality of exposure regions, and the regions are exposed by one Y-direction scanning. In the case of FIG. 2, the exposure is performed by four Y-direction scanning of the exposure regions Al to A4. The above exposure regions are also referred to as shot regions. Figure 7 Figure 7

[0074] ​​The exposure area also has a plurality of or one correction point in the Y direction, and is divided into correction areas in the Y direction corresponding to the number of correction points. Each actuator drives to the command position while uniformly or accelerating / decelerating between the correction points in order to drive the shape of the optical element 301 at each correction point. In the case of Figure 8 , there are five correction points (correction point numbers 1 to 5), and are divided into four correction areas (virtually).

[0075] Hereinafter, for simplicity of explanation, assume that there are two actuators that grip and deform the optical element 301, and are denoted as actuators ACT1 and ACT2. Also, in Figure 9 , Figure 10 , the command values input to the actuators ACT1 and ACT2 are shown. Figure 9 is a graph showing the command value in the actuator ACT1, Figure 10 is a graph showing the command value in the actuator ACT2. In the graphs of Figure 9 and Figure 10 , the vertical axis is the driving position from the stroke center, and the horizontal axis is the correction point number.

[0076] The actuator ACT1 drives between 15 to 50 μm from the stroke center position, and the actuator ACT2 drives between 2 to 45 μm from the stroke center position. Each actuator repeatedly performs the same driving for the exposure areas Al to A4. Also, each time the substrate P is replaced, the actuators are driven by the same method.

[0077] However, if the actuators are driven as described above (for example, driven repeatedly by a predetermined motion), the wear of the sliding members of the actuators is localized. The sliding members are, for example, the ball screw 308, the Z linear guide 316, the Y linear guide 317, and the wedge linear guide 318 in Figure 4 . In the ball screw 308, rotation is performed by the rolling of balls in the thread groove, but the contact surface of the ball and the groove is worn. Also, in the case of a linear guide, the ball rolls on the rail, so the contact surface of the ball and the rail is worn. In the case of a cross roller guide, the rollers roll on the rail, so the contact surface of the rollers and the rail is worn. In the above, the case of repeatedly performing a predetermined motion is described, but the same range of driving is also included in a motion that is not exactly the same as the predetermined motion.

[0078] In the present embodiment, in order to reduce the localized wear of the sliding member, the stroke center positions of the actuators 302 are regularly shifted uniformly on the whole shaft. Uniformly means that the actuators are driven with almost no deviation on the whole shaft, and the proportion of the deviation amount of the adjacent actuators to each other with respect to the driving amount of the actuators can be within 5%. That is, the initial positions (starting positions) of the actuators 302 are uniformly changed on the whole shaft. Thereby, the wear can be dispersed, and the localized wear can be reduced. In addition, the driving region after the uniform shift is preferably not overlapped with the driving region before the uniform shift. Specifically, it is preferable that the range in which at least one of the actuators 302 is driven after the initial positions of the actuators 302 are changed is not overlapped with the range in which at least one of the actuators 302 is driven before the initial positions are changed. It is more preferable that the range in which all of the actuators 302 are driven after the initial positions of the actuators 302 are changed is not overlapped with the range in which all of the actuators 302 are driven before the initial positions are changed.

[0079] Therefore, the uniform shift amount is preferably more than the difference between the maximum value and the minimum value of the command positions of the actuators on the whole shaft. Here, it is not a necessary element of the present embodiment that the uniform shift amount is more than the difference between the maximum value and the minimum value of the command positions of the actuators on the whole shaft, and can be less than the difference between the maximum value and the minimum value.

[0080] If the uniform shift is applied to the driving distributions of the actuators ACT1, ACT2 shown in Figure 9 , Figure 10 , the driving distributions become Figure 11 , Figure 12 . Figure 11 is a graph showing the driving distribution of the actuator ACT1 in the present embodiment, Figure 12 is a graph showing the driving distribution of the actuator ACT2 in the present embodiment.

[0081] According to Figure 9 , Figure 10 , the maximum value of the command positions of the actuators on the whole shaft is 50 μm, and the minimum value is 2 μm. Therefore, the difference between the maximum value and the minimum value is 50 μm - 2 μm = 48 μm, and the shift amount can be 48 μm or more. The uniform shift amount is added to the command positions of the actuators. The control section C calculates the uniform shift amount, and transmits the command positions to which the uniform shift amount is added to the actuators. In the present embodiment, as described above, the stroke center positions of the actuators are uniformly shifted, and the actuators are driven, thereby the wear is dispersed, and the durability is improved.

[0082] In the present embodiment, the change of the initial position of the actuator 302 is performed at a timing at which the substrate P is not exposed (i.e., a timing between exposures). In the present embodiment, the addition of the uniform offset can be performed either when the scan exposure is performed a predetermined number of times or when a predetermined period of time elapses. The predetermined period of time can be, for example, one month or one year.

[0083] In addition, the addition of the uniform offset can also be performed by an instruction from a user. For example, the exposure apparatus EX can also have a user interface (console, touch panel, etc.) that receives an instruction from a user. By the user pressing a button for "uniform offset change" on the user interface, the addition of the uniform offset can be performed.

[0084] According to the above method, the longer the stroke that the actuator can drive and the smaller the difference between the maximum and minimum values of the command position of the entire shaft, the longer the life can be extended. For example, the stroke that the actuator can drive is set to 500 μm. In a case where the maximum value of the command position of the entire shaft is 50 μm and the minimum value is 2 μm, the difference is 48 μm, so the uniform offset is 48 μm. Within the stroke, the uniform offset can be performed 500 ÷ 48 ≈ 10 times, so the life of the actuator is extended by about 10 times. That is, the longer the stroke and the smaller the difference between the maximum and minimum values of the command position of the entire shaft, the more preferable. When the drive amount of each actuator that corrects the imaging error is calculated by the control section C, by setting the difference between the maximum and minimum values of the command position of the entire shaft as a constraint condition, the drive amount can be calculated in a manner that the number of times that the uniform offset can be performed is increased.

[0085] In the above, the method of calculating the uniform offset in which the drive region after the uniform offset does not overlap the drive region before the uniform offset is shown, but in this method, a region that is not used at all in driving is generated. For example, as described above, the drive stroke is set to 500 μm and the difference between the maximum and minimum values of the command position of the entire shaft is 48 μm. In this case, the uniform offset can be performed a total of 10 times, so 48 × 10 = 480 μm is used in driving, and the wear is dispersed within this range. However, the remaining 500 - 480 = 20 μm becomes a region that is not used at all in driving. A method of more effectively dispersing the wear by also using this region in driving is shown below.

[0086] In addition to making the uniform shift further smaller, the remaining region is made to be a minimum by increasing the frequency of the uniform shift. In this method, the drive region after the uniform shift can also overlap the drive region before the uniform shift. For example, as described above, the stroke is set to 500 μm, and the difference between the maximum value and the minimum value of the command position of the whole shaft is 48 μm. If the uniform shift amount is set to 2 μm, after the uniform shift, 2 μm becomes the new drive region, and the remaining 46 μm overlaps the drive region before the uniform shift. According to (500 - 48) ÷ 2 = 226, by a total of 226 times of the uniform shift, the entire 500 μm of the stroke is used. The uniform shift amount is not limited to this, and can be, for example, 1 μm or the like, which is smaller. In this case, the number of times of the uniform shift increases, and by (500 - 48) ÷ 1 = 502 times of the uniform shift, the entire driveable region is used. The driveable range refers to, for example, a range in which the optical sensor does not perform detection. By a smaller uniform shift amount, the frequency of the uniform shift is increased, the unused stroke is made to be a minimum, and the wear is dispersed over the entire stroke. The frequency of the uniform shift can be, for example, every day, every week, or the like.

[0087] In the case where the optical element 301 is a flat glass, even if the uniform shift is performed in the height direction, the imaging sensitivity matrix does not change, and thus, the imaging performance is not affected. That is, even if the stroke center position is uniformly shifted by the above-described method, the imaging performance does not change, and the durability of the slide member can be improved.

[0088] The stroke center position can also be uniformly shifted after the actuator's drive accuracy or correction performance has changed due to wear is detected by the sensor. For example, the stroke center position can also be uniformly shifted when the command position deviates from the current position read by the encoder by a prescribed value or more when the drive is corrected. Further, the stroke center position can also be uniformly shifted when the imaging performance measured by the imaging device AS becomes a prescribed value or less.

[0089] Errors in the dimensions of structural components, installation errors during assembly, and preload errors may be transmitted to the actuator 302, resulting in drive errors. Therefore, when the stroke center position is offset uniformly, the actuator may not drive 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 predetermined value, it tracks and drives in the direction where the deviation decreases. Additionally, if the change in imaging performance measured by the camera device AS exceeds a predetermined value before and after the uniform offset, it also tracks and drives in the direction where the change decreases. Imaging performance refers to optical aberrations such as distortion aberration and astigmatism. When driving to the uniform offset position, the motor 315 may lose synchronization. By reading the current position from the encoder 314 or measuring the imaging performance from the camera device AS, it is confirmed whether the motor 315 has lost synchronization. If synchronization has occurred, the drive speed is reduced to a level that prevents synchronization loss, and the motor is driven to the uniform offset position.

[0090] If the sliding component of the actuator experiences localized wear, it may fail to drive according to the command. The difference between the current position and the commanded position of the area with localized wear increases. Therefore, the driving accuracy in that area may be poor, and the imaging performance may deteriorate. To achieve high-precision driving even with wear, the command value in the worn area is multiplied by a constant. The constant is calculated based on the relationship between the command value from the main control unit C and the displacement of the encoder 314 after driving. 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, driving errors can be suppressed even with wear.

[0091] Additionally, lubricating oil is applied to the sliding component of actuator 302. The sliding component is... Figure 4 The ball screw 308, Z-direct-acting guide 316, Y-direct-acting guide 317, and wedge-shaped direct-acting guide 318 are coated with lubricating oil between the balls or rollers and the threaded grooves or tracks. By applying lubricating oil, direct contact between the components can be avoided, thus inhibiting wear. Furthermore, if the actuator 302 is repeatedly driven, the lubricating oil may slowly migrate outside the driving area. Therefore, by... Figure 13The uniform parallel driving is performed to and fro between the positive side limit and the negative side limit of the stroke, thereby making the lubricating oil in a uniform state. The frequency of the uniform parallel driving can be performed, for example, every time 1 substrate P is exposed, or can be performed every day. In addition, the driving method is not limited as long as the driving is performed in a manner that the lubricating oil diffuses, even if the driving is not uniform. If the actuator 302 is controlled to be driven beyond the range in which the actuator 302 is driven during the scanning exposure, the lubricating oil diffuses, so the driving is acceptable as long as it is such driving.

[0092] Next, the control method of the exposure apparatus EX in the present embodiment will be described. Figure 14 is a flowchart showing each process of the control method. Each process of the flowchart can be controlled by the control section C.

[0093] In step S1, the driving amount of the actuator 302 driven during the scanning exposure is calculated (calculation process). Specifically, the driving amount D is calculated from the imaging sensitivity matrix C which has been described in the above description.

[0094] In step S2, the substrate P is subjected to the scanning exposure (exposure process). At this time, as has been described in the above description, by deforming the optical element 301 by the actuator 302 while performing the exposure, it is possible to reduce the aberration.

[0095] In step S3, it is determined whether or not the change of the uniform offset is required (determination process). In the case where the change is required, the flowchart proceeds to step S4, and in the case where the change is not required, the flowchart is ended.

[0096] In step S4, the uniform offset is added, that is, the initial positions of the plurality of actuators 302 are changed uniformly (change process). Thereby, the driving region is changed before and after the change process, and it is possible to reduce the local abrasion.

[0097] According to the above description, in the present embodiment, by adding the uniform offset amount, it is possible to suppress the local abrasion, and it is possible to improve the durability of the optical unit.

[0098] <2nd Embodiment>

[0099] In the present embodiment, with reference to Figure 9 , Figure 10 , Figure 15 , Figure 16, which is a driving method for improving durability of the actuator 302. The driving method of the actuator 302 in the present embodiment is a method in which, by driving while adding a uniform offset to the entire axis during the scanning exposure, the number of passes through the same position in the stroke is minimized, thereby dispersing the wear. This means that the number of changes in the driving direction of each actuator is minimized. Further, regarding the same structure as the first embodiment and the like, the description is omitted.

[0100] Next, a method of driving the actuator while adding a uniform offset to the entire axis during the scanning exposure will be described. Here, in order to simplify the description, the number of actuators of the optical unit 300 is set to two, and is described as actuators ACT1 and ACT2. The driving profile of each axis is set to be Figure 9 , 10 , and the number of correction points at the time of scanning exposure in the Y direction is set to five points. The driving profile of the actuators ACT1 and 2 after adding the uniform offset is shown in Figure 15 , Figure 16 . For example, for the command position of the correction point number 5, the ACT1 and 2 are 15 μm and 30 μm, respectively, and the difference is 15 μm. For the command position at the correction point number 5 after the uniform offset, they are 75 μm and 90 μm, respectively, and the difference is also 15 μm. By performing the uniform offset during the scanning exposure without changing the positional relationship between the actuators, that is, without changing the shape of the optical element 301, the wear is dispersed. For example, in the actuator ACT1, before the uniform offset, according to Figure 9 , in the correction drive of the correction point numbers 1 to 5, the same position within the stroke is passed through a maximum of three times, but after the uniform offset, according to Figure 15 , the number of passes becomes once (not more than twice through the same position). Since the number of passes is reduced from three to one, the position of the wear is dispersed, and the durability is improved. In the above case, the number of passes becomes 1 / 3, so the life is extended about three times. In addition, in the case where the optical element 301 is a flat glass, even if the uniform offset is applied during the scanning exposure, the imaging performance does not change.

[0101] The less the number of times of passing through the same position within the stroke of the actuator, the more the durability is improved, so when calculating the driving amount, the number of passes can also be added as a constraint condition. In addition, in the case where the number of changes in the driving direction is small, the durability is also improved, so it can also be added as a constraint condition.

[0102] The uniform shift amount during the scan exposure process is calculated by the control section C. The calculation method is shown below. First, the control section C calculates the drive amount of each actuator that corrects the imaging error. Let the command position at the correction point number k of the i-th actuator be Vik. Further, if the uniform shift amount at the correction point number k is Uk, and the command position at the correction point number k of the i-th actuator after the uniform shift is Wik, it can be expressed as

[0103] Wik = Vik + Uk... (7).

[0104] At the correction point number 1, no uniform shift is needed, so Ul = 0, and Vii = Wii. After the correction point number 2, if the number of actuators is n, the uniform shift amount Uk can be expressed as

[0105] Uk = MAX((W1k-1) - Vik, (W2k-1) - V2k,..., (Wnk-1) - Vnk)... (8).

[0106] Here, the MAX() function is a function that returns the maximum value of the values within the parentheses.

[0107] The uniform shift amount is not limited to the above, and for example, it can be made to increase linearly for each correction point.

[0108] In this case, the uniform shift amount Uk at the correction point number k becomes Uk = A x k. Here, A is a constant. Further, in the case where the constant A is larger than the maximum value of the drive amount, it becomes a drive distribution in which the drive direction does not change, so the effect of dispersing the wear can be further expected. That is, the constant A can be expressed as A = MAX(V1k - (V1k-1), V2k - (V2k-1),..., Vnk - (Vnk-1))... (9).

[0109] In the method described above based on the uniform shift during the scan exposure process, the overall drive stroke becomes long, so the durability is improved, but the drive speed required for correction also becomes large. The larger the drive speed, the more likely it is that the motor 315 will lose synchronization. In addition, the larger the drive speed, the larger the drive error, so typically, the constraint condition on the drive speed when calculating the drive amount is more strict than in the method of the first embodiment.

[0110] Further, during the scanning exposure, the current position is always read by the encoder 314, and in a case where there is a deviation of a prescribed value or more from the command position, the control section C is notified. In this case, the control section C changes the constraint condition of the drive speed, and the drive amount is calculated again. The driving is performed in a new drive distribution in which the drive speed is changed, and the current position is always read by the encoder 314 during the scanning exposure. If there is a deviation of a prescribed value or more from the command position, the constraint condition of the drive speed is further changed, and the drive amount is calculated. Thereafter, the same calculation is repeatedly performed, and the drive amount is determined.

[0111] In the above description, the method in which the current position is read by the encoder 314 during the scanning exposure to measure the deviation from the command position is described, but the method in which the imaging performance is measured by the imaging device C during the scanning exposure to compare with the target value can also be used. In a case where there is a deviation of a prescribed value or more from the target value of the imaging performance, the constraint condition of the drive speed is changed, and the drive amount is calculated again.

[0112] Next, the control method of the exposure apparatus EX in the present embodiment will be described. Figure 17 is a flowchart showing each process of the control method. Each process of the flowchart can be controlled by the control section C.

[0113] In step S5, the drive amount of the actuator 302 that drives during the scanning exposure is calculated (calculation process). Specifically, the drive amount D is calculated in accordance with the imaging sensitivity matrix C that has been described in the above description.

[0114] In step S6, the substrate P is subjected to the scanning exposure (exposure process). At this time, as has been described in the above description, by deforming the optical element 301 by the actuator 302 while performing the exposure, it is possible to reduce the aberration.

[0115] In step S7, it is determined whether or not the change of the uniform deviation is required (determination process). In a case where it is required, the flowchart proceeds to step S8, and in a case where it is not required, the flowchart is ended.

[0116] In step S8, the uniform deviation is added, that is, the initial positions of the plurality of actuators 302 are changed uniformly (change process). Thereby, the drive region is changed before and after the change process, and it is possible to reduce the local abrasion. In the present embodiment, the change of the initial position is performed during the scanning exposure in parallel with step S6 and steps S7 and S8, which is different from the first embodiment. Further, step S7 can be performed before step S6 is performed, without being performed in parallel with step S6.

[0117] According to the above, in the present embodiment, by adding a uniform offset during the scanning exposure, it is possible to suppress local abrasion and improve the durability of the optical unit.

[0118] <3rd Embodiment>

[0119] The present embodiment is a method in which, in the process of calculating the driving amount of the actuator, a constraint condition on the driving direction during the scanning exposure is applied, thereby minimizing the number of times the same part is passed through and dispersing the abrasion. The method of applying the constraint condition to the driving direction is shown below.

[0120] Wik < Wi(k+1) is satisfied when the command position at the correction point number k of the i-th actuator is set to Wik. For example, in the case where the number of correction points is 5 points, Wil < Wi2 <... < Wi5 is satisfied with respect to all the actuators. By adding this constraint condition in the process of calculating the driving amount for correcting the imaging error, the actuator does not make a driving turnaround during the scanning exposure, but consistently drives in the same direction. For example, in the case where there is no constraint condition on the driving direction in the exposure area where the number of correction points is 5 points, the maximum number of driving direction turnarounds is 3. The number of times the same part is passed through within the stroke is 4. In the case where the constraint condition of consistently driving in the same direction is applied, there is no driving direction turnaround, and the same part is passed through only once. Therefore, the durability is improved by 4 times compared to the case where there is no constraint condition. In the case where Wil < Wi2 <... < Wi5, the vertical direction is consistently driven upward, but the constraint condition can also be applied in such a way that it is consistently driven downward, in which case Wil > Wi2 >... > Wi5.

[0121] That is, in the present embodiment, the control section C causes the plurality of driving sections to drive while exposing the substrate, so that the direction in which each of the plurality of driving sections drives is not switched during the exposure of the substrate.

[0122] In addition, it is not necessarily required to consistently drive in the same direction in all the exposure areas, but it is also possible to consistently drive in the same direction only between certain correction points. For example, it is also possible to consistently drive the correction point numbers 1 to 2 upward in the vertical direction, and consistently drive the correction point numbers 3 to 5 downward in the vertical direction, like Wil < Wi2 < Wi3 > Wi4 > Wi5. The number of times the same part is passed through increases to 2 times, but the overall stroke becomes shorter, and the margin before the limit is reached increases. In addition, it is also possible to combine the constraint on the driving direction with the initial position change.

[0123] <Embodiment of Method of Manufacturing Article>

[0124] The manufacturing method of the article of the embodiment of the present application is suitable for manufacturing, for example, an article such as a flat panel display (FPD), a semiconductor device, a sensor, an optical element, and the like. Figure 18 is a flowchart of the manufacturing method of the article of the present embodiment. The manufacturing method of the article of the present embodiment includes a step of obtaining an exposed substrate by forming a latent image pattern on a photosensitive material applied to a substrate by exposure performed by the exposure apparatus EX described above (exposure step, step S11). In addition, a step of obtaining a developed substrate by developing the substrate exposed in the step described above (development step, step S12) is included. Further, the manufacturing method described above includes other publicly known steps (oxidation, film formation, evaporation, doping, planarization, etching, resist peeling, cutting, bonding, packaging, and the like) (processing step, step S13). The manufacturing method of the article in the present embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of the article compared to the conventional method.

[0125] The above describes the preferred embodiments of the present application, but it goes without saying that the present application is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist thereof.

[0126] According to the present application, it is possible to provide an exposure apparatus that is advantageous in improving the durability of an optical unit.

[0127] ★★★

[0128] While the present application has been described with reference to example embodiments, it is to be understood that the application is not limited to the disclosed example embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

[0129] This application claims the benefit of Japanese Patent Application No. 2024-090296 and No. 2024-181941, filed July 24, 2024, and No. 2024-181941, filed July 24, 2024, the entire contents of which are incorporated herein by reference.

Claims

1. An exposure apparatus which exposes an image of a pattern of a master to a substrate, the exposure apparatus characterized by comprising: an optical member disposed in an optical path through which light from a light source passes; a plurality of driving sections disposed at a plurality of portions of the optical member to deform the optical member; and a control section which controls driving of the plurality of driving sections, the control section changing initial positions of the plurality of driving sections in unison.

2. The exposure apparatus according to claim 1, wherein the control section changes the initial positions in such a manner that a range in which at least one of the plurality of driving sections drives after the initial positions are changed does not overlap with a range in which at least one of the plurality of driving sections drives before the initial positions are changed.

3. The exposure apparatus according to claim 2, wherein the control section changes the initial positions in such a manner that a range in which all of the plurality of driving sections drive after the initial positions are changed does not overlap with a range in which all of the plurality of driving sections drive before the initial positions are changed.

4. The exposure apparatus according to claim 1, wherein the control section changes the initial positions at a timing at which the substrate is not exposed.

5. The exposure apparatus according to claim 1, further comprising a user interface which receives an instruction from a user, wherein the control section changes the initial positions based on the instruction.

6. The exposure apparatus according to claim 1, further comprising an encoder which measures positions of the plurality of driving sections, wherein the control section controls the plurality of driving sections in such a manner that the positions of the plurality of driving sections measured by the encoder become reference positions.

7. The exposure apparatus according to claim 1, wherein the control section individually controls the plurality of driving sections while exposing the substrate.

8. The exposure apparatus according to claim 1, wherein the optical member includes a flat glass.

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

10. An exposure apparatus which exposes an image of a pattern of a master to a substrate, the exposure apparatus characterized by comprising: an optical member disposed in an optical path through which light from a light source passes; a plurality of driving sections disposed at a plurality of portions of the optical member to deform the optical member; and a control section which controls driving of the plurality of driving sections, the control section changing initial positions of the plurality of driving sections in unison while exposing the substrate.

11. The exposure apparatus according to claim 10, wherein the optical member includes a flat glass.

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

13. An exposure apparatus which exposes an image of a pattern of a master to a substrate, the exposure apparatus characterized by comprising: an optical member disposed in an optical path through which light from a light source passes; a plurality of driving sections disposed at a plurality of portions of the optical member to deform the optical member; and a control section which controls driving of the plurality of driving sections, the control section changing initial positions of the plurality of driving sections in unison while exposing the substrate. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ a control section that controls driving of the plurality of driving sections, the control section drives the plurality of driving sections while exposing the substrate, so that the direction in which each of the plurality of driving sections is driven does not switch during exposure of the substrate.

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

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

16. A control method of an exposure apparatus that exposes an image of a pattern of a master onto a substrate, the control method characterized by comprising: an exposure process of exposing the substrate while controlling driving of a plurality of driving sections that are arranged at a plurality of positions of an optical element arranged in an optical path through which light from a light source passes and deforms the optical element; and a change process of changing initial positions of the plurality of driving sections uniformly.

17. The control method according to claim 16, wherein the change process changes the initial positions in such a manner that a range in which at least one of the plurality of driving sections is driven after the change process is performed does not overlap with a range in which at least one of the plurality of driving sections is driven before the change process is performed.

18. The control method according to claim 16, wherein the change process is performed at a timing at which the substrate is not exposed.

19. A control method of an exposure apparatus that exposes an image of a pattern of a master onto a substrate, the control method characterized by: an exposure process of exposing the substrate while controlling driving of a plurality of driving sections that are arranged at a plurality of positions of an optical element arranged in an optical path through which light from a light source passes and deforms the optical element; and a change process of changing initial positions of the plurality of driving sections uniformly while the exposure process is performed.

20. A method of manufacturing an article, characterized by, comprising: an exposure process of exposing a substrate using the exposure apparatus according to any one of claims 1 to 10 to obtain an exposed substrate; and a development process of developing the exposed substrate to obtain a developed substrate, manufacturing an article from the developed substrate.

Images