Exposure apparatus, exposure method, and article manufacturing method

Abstract

The invention relates to an exposure apparatus, an exposure method, and an article manufacturing method. Provided is a technique that facilitates high accuracy of focus control. An exposure apparatus for scanning and exposing a substrate includes: a mounting table for holding and moving the substrate; at least one actuator for adjusting at least one of the height and the inclination of the mounting table; a measuring unit that measures a surface position of the substrate; and a control unit that controls the actuator on the basis of a measurement value obtained from the measurement unit. The control unit determines a limit value for the amount of drive of the mounting table by the actuator on the basis of time-series data of measurement values obtained from the measurement unit.

Description

Technical Field

[0001] The present invention relates to an exposure device, an exposure method and an article manufacturing method. Background Art

[0002] In order to transfer a good circuit pattern to the entire exposed area of ​​the substrate using the exposure device, it is necessary to reliably position the entire exposed area within the allowable focal depth of the reduction projection lens system. To this end, it is important to accurately detect the position and inclination of the substrate surface relative to the focal plane of the reduction projection lens system, that is, the plane on which the circuit pattern image of the mask is focused, and to adjust the position and inclination of the substrate surface by focusing drive.

[0003] In the step-and-scan method, it is necessary to make the slit exposure area on the substrate coincide with the imaging surface one by one during scanning. Therefore, in the step-and-scan method, a so-called pre-reading method is adopted. In this pre-reading method, a focusing and leveling sensor (hereinafter referred to as a "pre-reading sensor") arranged near the front side of the scanning direction is used to measure the focusing and leveling offset of the substrate near the front side of the slit exposure area. By performing focusing and leveling drive based on the measurement result, the substrate surface at the measured location is made consistent with the imaging surface of the projection optical system before the measured location reaches the slit exposure area. In such a pre-reading method, the driving amount of the focusing and leveling drive is calculated based on the discretely obtained measurement values.

[0004] However, in addition to the step difference (process step difference) caused by the formed pattern, there may also be local deflection of the substrate itself, adsorption step difference caused by the chuck used to hold the substrate, step difference caused by foreign matter, etc. In this case, the drive amount calculated by the pre-reading sensor sometimes becomes larger. When following a step difference that is not a process step difference, the problem of reduced following accuracy of focusing and leveling arises. That is, in the step scanning method, unlike the step repetition method, the measurement and drive for focusing and leveling are repeated in sequence during scanning exposure, so the drive amount of focusing and leveling drive affects the exposure accuracy. Therefore, in the prior art, the improvement of focusing and leveling following accuracy is sought by setting a limit value for the discretely obtained focusing and leveling drive amount.

[0005] On the other hand, the limit of the driving amount may sometimes become excessively limited depending on the driving mode (for example, when the scanning speed is slow). In response to such a problem, Patent Document 1 proposes changing the limit value according to the speed, acceleration, jerk (rate of change of acceleration) in the scanning direction when the substrate stage is scanning, or the position of the substrate stage, so as to avoid the disadvantages caused by excessive driving limit.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent No. 4840958 Summary of the invention

[0009] Problem that the invention aims to solve

[0010] There are the above-mentioned prior arts. On the other hand, sometimes the substrate stage is driven continuously in one direction during the focus drive or the leveling drive due to the warpage of the outer peripheral portion of the substrate or the process step difference. In such a case, even when the scanning speed is fast, the substrate stage does not have a large deviation, so the limit value of the driving amount of the focus drive or the leveling drive can sometimes be allowed.

[0011] However, in the prior art, the limit value of the drive amount of the substrate stage in the focus drive or the leveling drive is fixed. Therefore, even if the substrate stage can follow, the drive amount is limited, resulting in a focus error.

[0012] The present invention provides, for example, a technique that contributes to improving the accuracy of focus control.

[0013] Solutions for solving problems

[0014] According to the first aspect of the present invention, there is provided an exposure device for performing scanning exposure on a substrate, characterized in that the exposure device comprises: a stage for holding and moving the substrate; at least one actuator for adjusting at least one of the height and the inclination of the stage; a measuring unit for measuring the surface position of the substrate; and a control unit for controlling the actuator based on the measurement value obtained from the measuring unit, wherein the control unit determines a limit value for the driving amount of the stage by the actuator based on time series data of the measurement value obtained from the measuring unit.

[0015] According to a second aspect of the present invention, there is provided an exposure method for performing scanning exposure on a substrate held by a stage, characterized in that the exposure method comprises the following steps: measuring the surface position of the substrate; determining a limit value of a driving amount of the stage by at least one actuator for adjusting at least one of the height and the inclination of the stage based on time series data of the measurement values ​​obtained by the measurement; and using the actuator to drive the stage with a driving amount limited to less than the limit value to expose the substrate.

[0016] According to the third aspect of the present invention, there is provided a method for manufacturing an article, characterized in that it includes: a process of exposing a substrate according to the exposure method of the second aspect above; and a process of developing the exposed substrate, and manufacturing an article from the developed substrate.

[0017] Effects of the Invention

[0018] According to the present invention, for example, a technique that is useful for improving the accuracy of focus control can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a figure which shows the structure of an exposure apparatus.

[0020] Figure 2 This is a diagram for explaining the pre-reading method.

[0021] Figure 3 It is a diagram for explaining the drive control of the substrate mounting table in the embodiment.

[0022] Figure 4 It is a diagram for explaining the drive control of the substrate mounting table in the embodiment.

[0023] Figure 5 is a flowchart showing an exposure method.

[0024] Figure 6 It is a diagram for explaining the drive control of the substrate mounting table in the embodiment.

[0025] Figure 7 This is a diagram for explaining the prior art in which defocusing occurs due to a fixed limit value.

[0026] Description of Reference Numerals

[0027] 100: exposure device, 101: projection optical system, 102: mask, 103: mask mounting table, 104: substrate, 105: substrate mounting table, 106: illumination optical system, 127: main control unit. DETAILED DESCRIPTION

[0028] Hereinafter, the embodiments are described in detail with reference to the attached drawings. It should be noted that the following embodiments do not limit the invention involved in the claims. A plurality of features are described in the embodiments, but these plurality of features are not limited to being all necessary features for the invention, and a plurality of features may be combined arbitrarily. Furthermore, in the attached drawings, the same or identical structures are marked with the same reference numerals, and repeated descriptions are omitted.

[0029] <First Embodiment>

[0030] Figure 1: is a diagram showing the structure of the exposure device 100 in the embodiment. In this specification and the drawings, directions are shown in an XYZ coordinate system in which a horizontal plane is set as an XY plane. Usually, the substrate 104 is placed on the substrate stage 105 in a manner that its surface is parallel to the horizontal plane (XY plane). Therefore, the directions orthogonal to each other in the plane along the substrate mounting surface of the substrate stage 105 are set as the X-axis and the Y-axis, and the direction perpendicular to the X-axis and the Y-axis is set as the Z-axis. In addition, the directions parallel to the X-axis, the Y-axis, and the Z-axis in the XYZ coordinate system are referred to as the X-direction, the Y-direction, and the Z-direction, and the rotation direction around the X-axis, the rotation direction around the Y-axis, and the rotation direction around the Z-axis are referred to as the θX direction, the θY direction, and the θZ direction, respectively.

[0031] The exposure device 100 transfers the pattern of the mask 102 to the substrate 104 while scanning the mask 102 and the substrate 104 as the original. The exposure device 100 is an exposure device (scanner) of a step-and-scan method that performs exposure by relatively scanning the mask 102 and the substrate 104 with an exposure area set to a rectangular or arc slit shape. Figure 1 As shown, the exposure apparatus 100 includes a projection optical system 101, a mask stage 103, a substrate stage 105, an illumination optical system 106, a main control unit 127, and a measuring unit MU.

[0032] exist Figure 1 , the optical axis AX of the projection optical system 101 extends in the Z direction, and the image plane of the projection optical system 101 is in a perpendicular relationship to the Z direction. The mask 102 is held by the mask mounting table 103. The pattern of the mask 102 is projected at a magnification (e.g., 1 / 4, 1 / 2, 1 / 5) of the projection optical system 101, and an image is formed on the image plane of the projection optical system 101.

[0033] The substrate 104 is, for example, a substrate on which a resist (photosensitive agent) is coated. A plurality of shooting areas having the same pattern structure formed by the previous exposure process are arranged on the substrate 104. The substrate stage 105 is a stage that holds the substrate 104 and moves, and has a chuck that adsorbs (fixes) the substrate 104. The substrate stage 105 can include at least one actuator for adjusting at least one of the height and inclination of the stage. For example, the substrate stage 105 includes an XY stage that can move horizontally in the X direction and the Y direction, respectively, and a Z stage that can move in the Z direction (the height direction of the substrate 104) in a direction parallel to the optical axis AX of the projection optical system 101. Furthermore, the substrate stage 105 can include a leveling stage that can rotate in the θX direction and the θY direction, and a rotating stage that can rotate in the θZ direction. In this way, the substrate stage 105 constitutes a 6-axis drive system for making the image of the pattern of the mask 102 consistent with the shooting area of ​​the substrate 104. The position of the substrate stage 105 in the X direction, the Y direction, and the Z direction is always measured by the strip mirror 123 and the interferometer 124 disposed on the substrate stage 105 .

[0034] The measuring unit MU has a function of measuring the surface position (position in the height direction) and the inclination of the substrate 104. In the present embodiment, the measuring unit MU can measure the position in the height direction of the measurement target portion of the imaging region of the substrate 104 held by the substrate stage 105. The measuring unit MU can include two each of the light source 110, the collimating lens 111, the slit member 112, the light-projecting side optical system 113, the light-projecting side reflector 114, the light-receiving side reflector 115, the light-receiving side optical system 116, the blocking aperture 117, the correction optical system 118, and the photoelectric conversion element 119. Based on the measurement result of the measuring unit MU, the height and the inclination of the substrate stage 105 can be controlled.

[0035] The light source 110 can be composed of a lamp or a light emitting diode. The collimating lens 111 converts the light from the light source 110 into parallel light with a roughly uniform intensity distribution in the cross section. The slit member 112 is formed by bonding a pair of prisms (prism-shaped members) in a manner that the inclined surfaces face each other. On the bonding surface, a plurality of openings (six pinholes in this embodiment) are formed using a shading film such as chromium. The projection side optical system 113 is a bilateral telecentric system that guides the light passing through the six pinholes of the slit member 112 to the six measurement object locations of the shooting area of ​​the substrate 104 via the projection side reflector 114.

[0036] With respect to the projection side optical system 113, the plane (bonding surface) in which the pinhole is formed and the plane including the surface of the substrate 104 are set to satisfy the Schaumfler condition. In the present embodiment, the incident angle Φ (angle with the optical axis AX) of the light from the projection side optical system 113 to the substrate 104 is 70 degrees or more. The six lights from the projection side optical system 113 are incident on each independent measurement object portion on the substrate to form an image. In addition, the light from the projection side optical system 113 is incident from the direction rotated by θ degrees (for example, 22.5 degrees) in the XY plane from the X direction in such a manner that the six measurement object portions on the substrate can be observed independently of each other.

[0037] The light receiving side optical system 116 is a bilateral telecentric system. The six lights (reflected lights) reflected at the respective measurement target locations of the substrate 104 enter the light receiving side optical system 116 via the light receiving side reflector 115. The blocking aperture 117 is arranged inside the light receiving side optical system 116 and is provided in common to the six measurement target locations. The blocking aperture 117 blocks the high-order diffracted light (noise light) generated by the pattern formed on the substrate 104.

[0038] The optical axes of the light passing through the light-receiving side optical system 116 are parallel to each other. The correction optical system 118 includes 6 correction lenses, which re-image the 6 lights passing through the light-receiving side optical system 116 into point lights of the same size relative to the photoelectric conversion surface (light-receiving surface) of the photoelectric conversion element 119. In addition, in the present embodiment, the light-receiving side optical system 116, the blocking aperture 117, and the correction optical system 118 perform optical surface skew correction in a manner that makes each measurement object portion on the substrate and the photoelectric conversion surface of the photoelectric conversion element 119 conjugate with each other. Therefore, there is no change in the position of the pinhole image on the photoelectric conversion surface caused by the local tilt of each measurement object portion on the substrate, and the pinhole image changes on the photoelectric conversion surface according to the change in the height of each measurement object position in the direction parallel to the optical axis AX. Here, the photoelectric conversion element 119 can be composed of 6 one-dimensional CCD line sensors, for example, but can also be composed by configuring a plurality of two-dimensional sensors.

[0039] As described above, the mask 102 is held by the mask stage 103. The mask stage 103 is scanned at a constant speed in the X direction (the direction of the arrow 103a) in a plane perpendicular to the optical axis AX of the projection optical system 101. At this time, the mask stage 103 is scanned (calibrated drive) in such a manner that the position of the mask stage 103 in the Y direction always maintains the target position. The positions of the mask stage 103 in the X direction and the Y direction are always measured by the strip mirror 120 and the interferometer 121 arranged on the mask stage 103.

[0040] The illumination optical system 106 uses light from a light source that generates pulsed light, such as an excimer laser, to illuminate the mask 102. The illumination optical system 106 includes a beam shaping optical system, an optical integrator, a collimating lens, a reflector, and a shielding blade, etc., which efficiently transmits or reflects pulsed light in the far ultraviolet region. The beam shaping optical system shapes the cross-sectional shape (size) of the incident light into a predetermined shape. The optical integrator makes the light distribution characteristics of the light uniform and illuminates the mask 102 with uniform illumination. The shielding blades define a rectangular illumination area corresponding to the chip size. The pattern of the mask 102 partially illuminated in the illumination area is projected onto the substrate 104 via the projection optical system 101.

[0041] The main control unit 127 includes a CPU, a memory, etc., and comprehensively controls each part of the exposure device 100. The main control unit 127 controls the mask stage 103 holding the mask 102 and the substrate stage 105 holding the substrate 104 so that the light of the pattern from the mask 102 is imaged on a predetermined area of ​​the substrate 104. For example, the main control unit 127 adjusts the position of the substrate 104 in the XY plane (the position in the X direction and the Y direction and the rotation position in the θZ direction) and the position in the Z direction (the rotation position in the θX direction and the θY direction) via the substrate stage 105. Similarly, the main control unit 127 adjusts the position of the mask 102 in the XY plane (the position in the X direction and the Y direction and the rotation position in the θZ direction) and the position in the Z direction (the rotation position in the θX direction and the θY direction) via the mask stage 103. In addition, the main control unit 127 causes the mask stage 103 and the substrate stage 105 to scan synchronously with respect to the projection optical system 101. In this way, the main control unit 127 controls the exposure process of exposing each shot region of the substrate 104 in the exposure region while scanning the substrate 104 with the substrate stage 105 .

[0042] When the mask stage 103 is scanned in the direction of the arrow 103a, the substrate stage 105 is scanned in the direction of the arrow 105a at a speed corrected for the magnification (reduction magnification) of the projection optical system 101. The scanning speed of the mask stage 103 is determined based on the width of the shielding blade in the illumination optical system 106 in the scanning direction and the sensitivity of the resist applied to the surface of the substrate 104 in order to facilitate productivity.

[0043] The pattern of the mask 102 is aligned in the XY plane based on the position of the mask stage 103, the position of the substrate stage 105, and the position of each shot region on the substrate 104 relative to the substrate stage 105. As described above, the position of the mask stage 103 and the position of the substrate stage 105 are measured by the interferometers 121 and 124, respectively. The position of each shot region on the substrate 104 relative to the substrate stage 105 can be obtained by detecting the position of the mark provided on the substrate stage 105 and the position of the alignment mark formed on the substrate 104 by an alignment scope (not shown).

[0044] The alignment of the pattern of the mask 102 in the Z direction, that is, the alignment of the projection optical system 101 to the image plane is achieved by controlling the substrate stage 105 (including the leveling stage) based on the measurement result of the measuring unit MU.

[0045] Figure 2 The focusing and leveling driving during step scanning are shown. The measuring unit MU functions as a focusing sensor (pre-reading sensor) that measures the surface position of the exposure area in a pre-reading manner. The pre-reading method refers to a method of measuring the surface position of the shooting area before the shooting area of ​​the substrate 104 held by the substrate stage 105 reaches the exposure position under the projection optical system 101. When exposing the Nth shooting area, the slit exposure area 201 passes through the entire area of ​​the Nth shooting area by scanning the substrate stage 105 in the +Y direction, and the Nth shooting area is exposed. The pre-reading sensor can include three sensors 202, 203, and 204 arranged in the X direction. Using these sensors, the positions of three points arranged in the X direction at a position closer to the -Y direction than the slit exposure area are measured, thereby measuring the focus and leveling deviation of the area in front of the slit exposure area. If the measurement values ​​of each sensor are defined as Z202, Z203, and Z204, the focus (Z) offset ΔFc and the leveling (θY) offset ΔLv are obtained by the following equations.

[0046] ΔFc=(Z202+Z203+Z204) / 3…(1)

[0047] ΔLv=(Z202-Z204) / D…(2)

[0048] Wherein, D represents the distance between the sensors 202 and 204 in the X direction on the substrate.

[0049] In this way, the focus offset (ΔFc) is calculated based on the average value of the measured values ​​at 3 points, and the leveling offset (ΔLv) is calculated based on the difference value of the measured values ​​at 2 points (Z202 and Z204). Before reaching the slit exposure area 201 through scanning, the measurement of the focus offset and the leveling offset is continued, and the measurement results are sent to the main control unit 127. It should be noted that the calculation formulas for ΔFc and ΔLv are not limited to formulas (1) and (2). In addition, the scanning direction is opposite in the (N+1)th shooting area, so the slit exposure area 201 is scanned in the -Y direction. When scanning in the -Y direction, the area closer to the +Y direction than the slit exposure area is measured by the pre-reading sensors 205, 206, and 207.

[0050] The main control unit 127 sequentially generates a target trajectory for aligning the slit exposure area with the imaging surface of the projection lens 4 based on the focus and leveling offsets measured and sent by the pre-reading sensor. Here, the measurement of the pre-reading sensor is performed at a constant interval (for example, 0.5 mm pitch) within the shooting area, and focusing and leveling drive are performed for each measurement. The target trajectory generated using the values ​​of ΔFc and ΔLv is set to Fc(y) and Lv(y), respectively. Here, y represents the position of the substrate mounting table 105 in the Y direction (scanning direction). In addition, (y) represents a function of y. These functions Fc(y) and Lv(y) are arbitrary functions such as straight lines, quadratic functions, trigonometric functions, etc.

[0051] Fc(y) and Lv(y) sometimes become values ​​with large local variations due to local deflection of the substrate, adsorption step differences caused by the chuck used to hold the substrate, step differences caused by dust, etc. Therefore, if Fc(y) and Lv(y) are directly applied as command values, the drive command value for the substrate mounting table 105 may contain a large high-frequency component. However, there is an upper limit to the following performance (following frequency) of the focusing and leveling drive mechanism, so even if you want to drive it at a high frequency exceeding this upper limit, you cannot completely follow it. When this state is reached, not only will it be impossible to completely follow the local step differences, but there will also be a problem of the exposure surface being greatly offset from the imaging surface in the subsequent exposure area.

[0052] In the prior art, a limit is set on the driving amount of the substrate stage 105. When a target value exceeding a certain value is given, the driving amount of the substrate stage 105 is limited. In this way, by limiting the driving amount, the substrate stage 105 intentionally does not follow the target value that it cannot follow. Thus, the focus error is reduced.

[0053] However, depending on the warping of the substrate at the periphery of the substrate, the process step difference, etc., the measured values ​​of focusing and leveling may increase or decrease monotonically in one direction. When the target value changes in a ramp-like manner such as monotonically increasing or monotonically decreasing, sometimes the drive command value does not contain a high-frequency component even if the drive amount exceeds the limit value, and the substrate stage 105 can follow the target value. In such a case, the limit of the drive amount becomes an excessive limit, and although it can follow, it may be driven to a position deviating from the optimal focus plane due to the drive limit, which may become the main cause of defocusing.

[0054] exist Figure 7 703 shows the driving trajectory of the substrate stage 105 when the driving amount is limited by the conventional driving method when the measured values ​​of focusing and leveling increase monotonically in the same direction. The horizontal axis represents time t, and the vertical axis represents the position (height and inclination) of the substrate stage 105. The dotted line 701 represents the offset (error) of the surface position measured by the pre-reading sensor relative to the optimal focus plane. The dotted line 701 can also be understood as time series data of the measurement value obtained from the measuring unit MU. The solid line 703 represents the driving trajectory of the substrate stage 105. In the prior art, the driving amount of focusing and leveling of the substrate stage 105 is limited based on a fixed limit value. Therefore, when a measurement value d(705) larger than the limit value is measured, the driving amount of the substrate stage is limited to Limit702 which is smaller than d. When the measurement value d(705) exceeding Limit702 is continuously measured in one direction, due to the limitation of Limit702, the substrate stage 105 becomes like the driving trajectory 703, and defocus 704 occurs.

[0055] like Figure 7 In this way, when the measured value of the pre-read sensor increases or decreases monotonically in the same direction, the drive command value does not contain a high-frequency component, and the substrate stage 105 can follow it, so it is appropriate to make the limit value of the drive amount that follows the target value variable. In this embodiment, the differential value of the time series data of the measured value obtained from the pre-read sensor is calculated, and based on the differential value, the limit value of the drive amount of at least one actuator (6-axis drive system) on the substrate stage 105 is determined. For example, based on the sign and size of the differential value, the limit value of the drive amount is made variable. In this way, the disadvantages caused by excessive drive restrictions can be avoided. A specific example is described below. It should be noted that in the following description, the differential value of the time series data of the measured value is sometimes referred to as "differential value of the measured value".

[0056] Reference Figure 3 The drive control of the substrate mounting table 105 in the first embodiment will be described. Figure 3In FIG. 3 , the horizontal axis represents time t, and the vertical axis represents the position (height and inclination) of the substrate stage 105. The dotted line 301 represents the error of the surface position measured by the pre-read sensor relative to the optimal focus plane. The dotted line 301 can also be understood as a graph representing time series data of the measurement values ​​obtained from the measuring unit MU. The solid line 302 represents the drive trajectory of the substrate stage 105. Positions 303 to 308 on the drive trajectory are the target positions of the focusing and leveling drives performed at each measurement. When the substrate stage 105 moves from position 303 to position 304, the main control unit 127 calculates the drive amount of the substrate stage 105 based on the measurement value obtained by the pre-read sensor. When the calculated drive amount exceeds LimitA (309), the drive amount of the substrate stage 105 is limited to LimitA (309), and the substrate stage 105 moves to position 304 as the target value. Similarly, when the substrate stage 105 moves from the position 304 to the position 305, the main control unit 127 calculates the drive amount of the substrate stage 105 based on the measurement value obtained by the pre-read sensor. Here, the deviation from the optimal focus plane is set as ΔFc, and the differential value ΔZ of the drive amount of the substrate stage 105 is calculated according to the following formula. It should be noted that the differential value of the drive amount of the substrate stage 105 is synonymous with the differential value of the measurement value.

[0057] ΔZ(n)=(ΔFc(n)-ΔFc(n-1)) / T...(3)

[0058] Here, T is the focus and leveling drive time, which can be calculated based on the measurement interval and scanning speed of the pre-reading sensor, and n represents the number of focus and leveling drives.

[0059] The main control unit 127 compares the differential value of the measurement value obtained by the first measurement with the differential value of the measurement value obtained by the second measurement performed after the first measurement in the scanning exposure within one shot area. For example, ΔZ(n) is set as the differential value of the drive amount when driving from position 303 to position 304, and ΔZ(n+1) is set as the differential value of the drive amount when driving from position 304 to position 305. In this case, it can be seen that the differential values ​​of the two have the same sign, that is, the signs of the respective differential values ​​are consistent. When the signs of the differential values ​​are consistent, the substrate stage 105 is driven in one direction. When the substrate stage 105 is driven in one direction, no large deviation occurs in the substrate stage 105. Therefore, the limit value of the drive amount can be increased to LimitB (310) which is larger than LimitA. Similarly, when driving from position 305 to position 306, driving from position 306 to position 307, and driving from position 307 to position 308, the limit value can also be set to LimitB. By increasing the limit value when driving the substrate stage 105 in one direction, the defocus amount of the driving trajectory of the substrate stage 105 indicated by the solid line 302 can be made smaller than the defocus amount of the driving trajectory 311 of the substrate stage in the conventional art.

[0060] Next, refer to Figure 4 , the drive control of the substrate stage 105 when the measurement value of the pre-reading sensor changes from a monotonically increasing to a monotonically decreasing state is described. The horizontal axis represents time t, and the vertical axis represents the position of the substrate stage 105. The dotted line 401 represents the error of the surface position measured by the pre-reading sensor relative to the optimal focus plane. The dotted line 401 can also be understood as a graph representing the time series data of the measurement value obtained from the measuring unit MU. The solid line 402 represents the drive trajectory of the substrate stage 105. The limit value of the drive amount when the substrate stage 105 moves from the position 403 to the position 404 is set to LimitA (411). Thereafter, when the substrate stage 105 is driven from the position 404 to the position 405, from the position 405 to the position 406, and from the position 406 to the position 407, it is driven in one direction. Therefore, the main control unit 127 increases the limit value of the drive amount from LimitA (411) to LimitB (412) which is larger than it.

[0061] Next, when the substrate stage 105 is driven from position 407 to position 408, the differential value of the drive amount of the substrate stage 105 has a different sign. That is, the sign of the differential value is reversed. When the driving direction is reversed, the command value of the substrate stage contains a high-frequency component, in which case the follow-up characteristics may be reduced. Therefore, when the sign of the differential value is reversed, the main control unit 127 reduces the limit value of the drive amount from LimitB (412) to LimitA (411). Thereafter, when the substrate stage 105 is driven from position 408 to position 409 and from position 409 to position 410, it decreases monotonically, so the main control unit 127 increases the limit value of the drive amount to the limit value LimitB again.

[0062] Thus, according to the present embodiment, the limit value is dynamically changed based on the differential value of the drive amount. For example, when the drive direction of the substrate mounting table 105 changes from monotonically increasing to monotonically decreasing, the limit value of the drive amount can be dynamically and appropriately changed. Thus, the disadvantages caused by the limit of the drive amount can be eliminated, and the drive instruction value that cannot be followed can be appropriately limited.

[0063] Figure 5 This is a flowchart of the exposure method in this embodiment.

[0064] In S501 , the main control unit 127 starts exposure processing for photographing an exposure object.

[0065] In S502 , the main control unit 127 obtains data of the amount of deviation of the surface position measured by the pre-reading sensor from the optimal focus plane by measurement using the pre-reading sensor (focusing and leveling measurement).

[0066] In S503 , the main control unit 127 calculates the drive amount based on the difference between the measurement result in S502 and the current value of the substrate stage 105 , and calculates a differential value by dividing the calculated drive amount by the time required for the focus and leveling drive.

[0067] In S504, the main control unit 127 determines whether the measurement in S502 is the first measurement. If the measurement is the first measurement, the process proceeds to S507. In S507, the main control unit 127 sets the limit value of the driving amount to Limit A. If the measurement is not the first measurement, the process proceeds to S505.

[0068] In S505, the main control unit 127 compares the sign of the differential value obtained in S503 this time with the sign of the differential value obtained from the previous measurement. When the differential values ​​of the two have the same sign, the process proceeds to S506. When the differential values ​​of the two have different signs, the process proceeds to S507. In S506, the main control unit 127 sets the limit value of the drive amount to LimitB which is larger than LimitA. In S507, the main control unit 127 sets the limit value of the drive amount to LimitA. LimitA and LimitB are determined in such a way that the substrate mounting table 105 is driven in the determined mode without defocusing due to the control deviation generated.

[0069] In S508 , the main control unit 127 calculates a target value for the position of the substrate stage 105 based on the limit value set in S506 or S507 .

[0070] In S509 , the main control unit 127 drives the substrate stage 105 at the driving amount limited to a limit value or less in S508 , and then exposes the substrate 104 .

[0071] In S510, the main control unit 127 determines whether the exposure processing of the entire shooting area is completed. If the exposure processing of the entire shooting area is not completed, the process returns to S502 to implement the focus measurement of the next area. If the exposure processing of the entire shooting area is completed, the processing of the shooting area is completed. This process is performed for the next shooting area.

[0072] According to the processing flow described above, the main control unit 127 determines the drive amount of the substrate stage 105 so as not to exceed the limit value while updating the limit value based on the differential value of the time series data of the measurement value obtained from the measuring unit MU during scanning exposure. The exposure apparatus 100 is configured to perform scanning exposure on each of a plurality of shot regions of the substrate 104, and the main control unit 127 can change the limit value of the drive amount within one shot region.

[0073] <Second Embodiment>

[0074] Reference Figure 6 , the drive control of the substrate mounting table in the second embodiment is described. Figure 6In FIG. 6 , the horizontal axis represents time t, and the vertical axis represents the position of the substrate stage 105. The dotted line 601 represents the offset (error) of the surface position measured by the pre-reading sensor relative to the optimal focus plane. The dotted line 701 can also be understood as a graph showing the time series data of the measurement value obtained from the measuring unit MU. The solid line 602 represents the drive trajectory of the substrate stage 105. In the exposure device of the step-and-scan method, in order to improve productivity, a method of performing exposure processing during acceleration is sometimes used. In this case, the speed of the scanning direction of the substrate stage 105 changes during exposure. Since the measurement of the pre-reading sensor is performed at a constant interval (for example, 0.5 mm pitch), when the scanning speed changes, the cycle of the focusing and leveling drive also changes. For example, if the scanning speed becomes slower, the measurement time interval between the two points becomes longer, so the time of the focusing and leveling drive becomes longer. On the other hand, if the scanning speed becomes faster, the measurement time interval between the two points becomes shorter, so the time of the focusing and leveling drive becomes shorter. In addition, the drive amount that the substrate stage 105 can follow changes according to the time of the focusing and leveling drive. For example, the focusing and leveling drive time when the substrate stage 105 is driven from position 603 to position 604 is set to T. When the scanning speed increases during exposure, the drive time from position 604 to position 605 is T', and the drive time from position 605 to position 606 is T" (T>T'>T"). Here, when the drive amount from position 604 to the optimal focus plane is equal to the drive amount from position 605 to the optimal focus plane, the latter becomes larger with respect to their respective differential values. In such a case, the main control unit 127 sets LimitC (609) (LimitB>LimitC) according to the differential value from position 605 to position 606.

[0075] Thus, according to this embodiment, the main control unit 127 can adjust the change amount of the limit value of the driving amount according to the scanning speed in one imaging area. This can drive to the optimal focus plane with high accuracy without causing a following error.

[0076] <Implementation Method of Article Manufacturing Method>

[0077] The article manufacturing method of the embodiment of the present invention is suitable for manufacturing micro devices such as semiconductor devices, components with fine structures and other articles. The article manufacturing method of this embodiment includes: a process of forming a latent image pattern on a photosensitive agent coated on a substrate using the above-mentioned exposure device (a process of exposing the substrate); and a process of developing the substrate on which the latent image pattern is formed in this process. In addition, the manufacturing method includes other well-known processes (oxidation, film formation, evaporation, doping, flattening, etching, resist stripping, cutting, bonding, packaging, etc.). Compared with previous methods, the article manufacturing method of this embodiment is advantageous in at least one of the performance, quality, productivity and production cost of the article.

[0078] The present invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, claims are appended to disclose the scope of the invention.

Claims

1. An exposure device for scanning and exposing a substrate, characterized in that: The exposure device has: A stage for holding and moving the substrate; at least one actuator for adjusting at least one of the height and the inclination of the mounting platform; A measuring unit, which measures the surface position of the substrate; as well as a control unit that controls the actuator based on the measurement value obtained from the measurement unit, The control unit determines a limit value of the driving amount of the mounting table by the actuator based on time-series data of the measurement value obtained from the measuring unit.

2. The exposure device according to claim 1, characterized in that The control unit determines the limit value based on a differential value of time series data of measurement values ​​obtained from the measuring unit.

3. The exposure device according to claim 2, characterized in that The control unit determines the driving amount of the stage by the at least one actuator so as not to exceed the limit value while updating the limit value based on the differential value of the time series data of the measurement value obtained from the measurement unit during scanning exposure.

4. The exposure device according to claim 3, characterized in that The exposure device is configured to perform scanning exposure on each of the plurality of shot regions of the substrate. The control unit changes the limit value within one imaging area.

5. The exposure device according to claim 4, characterized in that In the scanning exposure within the one shooting area, when the differential value of the time series data of the measurement value obtained by the first measurement of the measuring unit and the differential value of the time series data of the measurement value obtained by the second measurement performed after the first measurement of the measuring unit have the same sign, the control unit increases the limit value.

6. The exposure device according to claim 4, characterized in that In the scanning exposure within the one shooting area, when the differential value of the time series data of the measurement value obtained by the first measurement of the measuring unit and the differential value of the time series data of the measurement value obtained by the second measurement performed after the first measurement of the measuring unit have different signs, the control unit lowers the limit value.

7. The exposure device according to claim 4, characterized in that The control unit adjusts a change amount of the limit value according to a scanning speed within the one imaging region.

8. The exposure device according to claim 1, characterized in that The measuring unit measures a surface position of a shot region of the substrate held by the mounting table before the shot region reaches an exposure position.

9. An exposure method for performing scanning exposure on a substrate held by a stage, characterized in that: The exposure method has the following steps: measuring a surface position of the substrate; determining a limit value of a driving amount of the stage by at least one actuator for adjusting at least one of a height and an inclination of the stage based on time series data of the measurement value obtained by the measurement; as well as The actuator drives the mounting table at a driving amount limited to or less than the limit value, thereby exposing the substrate.

10. A method for manufacturing an article, characterized in that: include: A step of exposing the substrate according to the exposure method of claim 9; as well as a step of developing the exposed substrate, An article is manufactured from the developed substrate.

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