Exposure apparatus and method for manufacturing article

Abstract

To provide a technique advantageous on the point of forming accuracy of a pattern onto a substrate in scanning exposure.SOLUTION: An exposure apparatus that performs scanning exposure of a shot region of a substrate by scanning the substrate with respect to exposure light, comprises: a measurement part which measures a surface position of the shot region in prior to exposure of the shot region within a measurement visual field by the exposure light during the scanning exposure; and a control part which performs focus-leveling control of the substrate on the basis of a measurement result of the measurement part in an overlapping part between the measurement visual field and the shot region during the scanning exposure, where the control part determines a parameter value for limiting the drive of the substrate in the focus-leveling control on the basis of information showing the size of the overlapping part.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] As one of the apparatuses used in the manufacturing process (lithography process) of semiconductor devices and the like, an exposure apparatus is used that performs scanning exposure of a shot area of ​​a substrate by scanning the substrate with exposure light emitted from a projection optical system. In such an exposure apparatus, during scanning exposure, the surface position is measured within the measurement field of view prior to exposure of the shot area with exposure light, and focus and leveling control of the substrate is performed based on the measurement result. Patent Document 1 describes that a limit value is set for the substrate drive amount in focus and leveling control, and focus and leveling control is performed so that the substrate drive amount does not exceed the limit value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-251788 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, in order to improve yield, scanning exposure is also performed on defective shot areas that are located on the periphery of the substrate and where only part of the original pattern is transferred. In such defective shot areas, the size of the overlapping area between the measurement field of view and the substrate changes during scanning exposure, and the measurement results of the surface position may vary significantly depending on the change in the size of the overlapping area. In this case, it is not possible to perform accurate focus and leveling control of the substrate, which can make it difficult to form the pattern on the substrate with high accuracy.

[0005] SUMMARY OF THE PRESENT EMBODIMENTS An object of the present invention is to provide a technique that is advantageous in terms of the accuracy of forming a pattern on a substrate in scanning exposure. [Means for solving the problem]

[0006] In order to achieve the above object, an exposure apparatus according to one aspect of the present invention is Using Shot area of ​​the substrate Against An exposure apparatus for performing scanning exposure, before a measurement unit that measures a surface position of the shot area within a measurement field prior to exposure of the shot area with the exposure light, and a control unit that performs focus leveling control of the substrate based on a measurement result of the measurement unit in an overlapping portion between the measurement field and the shot area during the scanning exposure, wherein the control unit: During the scanning exposure The size of the overlapping portion Changes Show change determining a parameter value for limiting driving of the substrate in the focus leveling control based on the information.

[0007] Further objects and other aspects of the present invention will become apparent from the following description of preferred embodiments with reference to the accompanying drawings. Effect of the Invention

[0008] According to the present invention, for example, it is possible to provide a technique that is advantageous in terms of the accuracy of forming a pattern on a substrate in scanning exposure. [Brief description of the drawings]

[0009] [Figure 1] Schematic diagram showing the configuration of an exposure apparatus [Diagram 2] A diagram showing the arrangement of multiple measurement points in the measurement unit. [Diagram 3] A diagram showing the positional relationship between the measurement field of view (measurement points) of the measurement unit and the irradiation area. [Figure 4] FIG. 1 shows the positional relationship between the measurement field of view of the measurement unit and the irradiation area. [Diagram 5]A diagram showing scanning exposure of a defective shot area in time series. [Figure 6] A graph showing the size of the effective area, the amount of change in the size of the effective area, and the control residual in each state. [Figure 7] Control block diagram for achieving focus leveling control [Figure 8] A graph showing the control residuals for each state [Figure 9] Flowchart showing parameter value determination processing during scanning exposure [Figure 10] A graph showing the size of the effective area, the amount of change in the size of the effective area, parameter values, and control residuals for each state. [Figure 11] A flowchart showing a process for determining a target trajectory of a substrate during scanning exposure. [Figure 12] Flowchart showing a method for exposing a substrate DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0011] First Embodiment An exposure apparatus 100 according to a first embodiment of the present invention will be described. The exposure apparatus 100 according to this embodiment is, for example, a so-called step-and-scan type exposure apparatus (scanning exposure apparatus) that performs scanning exposure of a shot area of ​​a substrate by scanning the substrate with exposure light (slit light, pattern light) emitted from a projection optical system. In the following description, the axial direction parallel to the optical axis of the projection optical system is defined as the Z-axis direction, and two axial directions perpendicular to each other in a plane perpendicular to the Z-axis direction are defined as the X-axis direction and the Y-axis direction. In the following description, when the term "X-axis direction" is used, it can be defined as including the +X direction and the -Y direction. The same applies to the "Y-axis direction" and the "Z-axis direction". In this embodiment, the relative scanning direction of the original 12 and the substrate 15 is defined as the Y-axis direction.

[0012] [Configuration of exposure equipment] 1 is a schematic diagram showing the configuration of an exposure apparatus 100 of the present embodiment. The exposure apparatus 100 can include an illumination optical system 11, an original stage 13, a projection optical system 14, a substrate stage 16, a measurement unit 17, a first detection unit 18, a second detection unit 19, and a controller 20. The controller 20 includes a CPU and a memory, and controls the entire exposure apparatus 100. In other words, the controller 20 controls the process of transferring a pattern formed on an original 12 (reticle, mask) onto a substrate 15 (wafer) (scanning and exposing the substrate 15).

[0013] The illumination optical system 11 uses a light-shielding member such as a masking blade included therein to shape light emitted from a light source (not shown) such as an excimer laser into, for example, a strip-shaped or arc-shaped exposure light (slit light) long in the X direction, and irradiates a part of the original 12 with the light. The original 12 and the substrate 15 are held by an original stage 13 and a substrate stage 16, respectively, and are disposed at optically conjugate positions via a projection optical system 14. The projection optical system 14 has a predetermined projection magnification (e.g., 1 / 2 or 1 / 4), and projects a pattern formed on the original 12 onto the substrate by the exposure light. The area of ​​the substrate 15 onto which the pattern of the original 12 is projected (area irradiated with the exposure light) is hereinafter referred to as an irradiation area 21. The original stage 13 and the substrate stage 16 are configured to be movable in a direction perpendicular to the optical axis of the projection optical system 14 (optical axis of the exposure light) (e.g., Y-axis direction), and are scanned relatively to each other at a speed ratio according to the projection magnification of the projection optical system 14 while synchronizing with each other. This allows the irradiation area 21 to be moved (scanned) on the substrate, and the pattern of the original 12 to be transferred onto the shot area 15a of the substrate. Then, by sequentially repeating such scanning exposure for each of the multiple shot areas 15a on the substrate, the exposure process for one substrate 15 can be completed.

[0014] The first detection unit 18 includes, for example, a laser interferometer, and detects the position of the original stage 13 (original 12). The laser interferometer included in the first detection unit 18, for example, irradiates a laser beam toward a reflector 13a provided on the original stage 13, and detects the displacement from a reference position on the original stage 13 by the laser beam reflected by the reflector 13a. This allows the first detection unit 18 to obtain the current position of the original stage 13 (original 12) based on the displacement. The second detection unit 19 includes, for example, a laser interferometer, and detects the position of the substrate stage 16 (substrate 15). The laser interferometer included in the second detection unit 19, for example, irradiates a laser beam toward a reflector 16a provided on the substrate stage 16, and detects the displacement from a reference position on the substrate stage 16 by the laser beam reflected by the reflector 16a. This allows the second detection unit 19 to obtain the current position of the substrate stage 16 (substrate 15) based on the displacement. Then, based on the current positions of the original stage 13 and the substrate stage 16 acquired by the first detection unit 18 and the second detection unit 19, respectively, the control unit 20 controls the driving of the original stage 13 and the substrate stage 16 in the XY directions. Here, the first detection unit 18 and the second detection unit 19 use laser interferometers when detecting the positions of the original stage 13 and the substrate stage 16, respectively, but the present invention is not limited to this and, for example, encoders may be used.

[0015] The measurement unit 17 measures the surface position (surface height) of the substrate 15 while the substrate stage 16 is moving in order to match the surface of the substrate 15 (hereinafter referred to as the substrate surface) with the imaging plane of the projection optical system 14. The measurement unit 17 in this embodiment is of an oblique incidence type that irradiates light obliquely onto the substrate 15, and includes an irradiation system 17a that irradiates the substrate 15 with light, and a light receiving system 17b that receives the light reflected by the substrate 15. Note that, hereinafter, the measurement of the surface position of the substrate 15 by the measurement unit 17 may be referred to as focus measurement.

[0016] The irradiation system 17a may include, for example, a light source 70, a collimator lens 71, a slit member 72, an optical system 73, and a mirror 74. The light source 70 is, for example, a lamp or a light-emitting diode, and emits light of a wavelength to which the resist on the substrate is not exposed. The collimator lens 71 converts the light emitted from the light source 70 into parallel light with a substantially uniform light intensity distribution in the cross section. The slit member 72 is composed of a pair of prisms bonded together so that their inclined surfaces face each other, and a light-shielding film made of chrome or the like in which a plurality of openings (for example, nine pinholes) are formed is provided on the bonded surface 72a. The optical system 73 is a double-telecentric optical system, and as shown in FIG. 2, nine light beams that have passed through the plurality of openings in the slit member 72 are incident on the substrate via the mirror 74. The optical system 73 is configured such that the surface in which the openings are formed and the surface including the substrate surface satisfy the Scheimpflug condition. In this embodiment, the mirror 74 is configured so that the angle φ (angle between the light beam and the optical axis of the projection optical system 14) at which each light beam emitted from the irradiation system 17a is incident on the substrate 15 is, for example, 70 degrees or more. As shown in FIG. 2, the irradiation system 17a is configured to cause nine light beams to be incident on the substrate 15 in a direction (XY direction) parallel to the substrate surface and at an angle θ (for example, 22.5 degrees) with respect to the scanning direction (Y direction) of the slit light. By causing the nine light beams to be incident on the substrate 15 in this manner, focus measurement can be performed individually at each of the nine measurement points 30 (multiple measurement points 30). Each of the multiple measurement points 30 is an area having a certain area.

[0017] The light receiving system 17b may include, for example, a mirror 75, a light receiving optical system 76, a correction optical system 77, a photoelectric conversion unit 78, and a processing unit 79. The mirror 75 guides the nine light beams reflected by the substrate 15 to the light receiving optical system 76. The light receiving optical system 76 is a double telecentric optical system and includes an aperture provided in common for the nine light beams. The aperture included in the light receiving optical system 76 blocks high-order diffracted light (noise light) generated due to the circuit pattern formed on the substrate. The correction optical system 77 has a plurality (nine) lenses corresponding to the nine light beams, and focuses the nine light beams on the light receiving surface of the photoelectric conversion unit 78 to form pinhole images on the light receiving surface. The photoelectric conversion unit 78 includes a plurality (nine) photoelectric conversion elements corresponding to the nine light beams. For example, a CCD line sensor or a CMOS line sensor is used as the photoelectric conversion element. Furthermore, processing unit 79 calculates the surface position of the substrate at each measurement point 30 based on the position of each pinhole image on the light receiving surface of photoelectric conversion unit 78. Here, in light receiving system 17b, tilt correction is performed so that each measurement point 30 on the substrate and the light receiving surface of photoelectric conversion unit 78 are conjugate with each other. Therefore, the position of each pinhole image on the light receiving surface of photoelectric conversion unit 78 does not change depending on the local tilt of each measurement point 30.

[0018] The measurement unit 17 thus configured can perform focus measurement (measurement of the surface position of the substrate 15) at each measurement point 30 based on the position of each pinhole image on the light receiving surface of the photoelectric conversion unit 78. This allows the control unit 20 to perform focus leveling control (also called focus leveling drive) of the substrate 15 based on the measurement results of the measurement unit 17 (each measurement point 30). The focus leveling control of the substrate 15 refers to controlling at least one of the height (position in the Z direction) and inclination (tilt in the ωX direction and ωY direction) of the substrate 15 by the substrate stage 16 so that the substrate surface is located at the target surface position. In addition, the target surface position can be set to, for example, the best focus position of the projection optical system 14 (image surface position of the projection optical system 14).

[0019] 3 is a diagram showing the positional relationship between nine measurement points 30 formed by the measurement unit 17 in the shot area 15a on the substrate and the irradiation area 21. As described above, the irradiation area 21 is an area irradiated with exposure light from the projection optical system 14, and has a rectangular shape as shown by the dashed line in FIG. 3, but may have an arc shape. 1 ~30a 3 is a measurement point 30 arranged inside the irradiation area 21, and performs focus measurement inside the irradiation area 21 in parallel with exposure of the shot area 15a in the irradiation area 21. 1 ~30b 3 and measurement point 30c 1 ~30c 3 is a measurement point 30 arranged at a position spaced a distance Lp from the irradiation area 21 in the scanning direction (±Y direction). 1 ~30b 3 and measurement point 30c 1 ~30c 3 is used to perform focus measurement prior to exposure of the shot area 15a in the irradiation area 21, and is switched according to the scanning direction of the substrate 15 (substrate stage 16).

[0020] For example, in the case where scanning exposure is performed by scanning the substrate 15 in the direction of the arrow F, the measurement point 30b is set at the position where the substrate 15 is exposed to light prior to the exposure of the shot area 15a in the irradiation area 21. 1 ~30b 3 In this case, the control unit 20 performs the focus measurement at the measurement point 30b 1 ~30b 3 Based on the results (measurement values) of focus measurements sequentially performed by the focus measuring device 20, the control device 20 sequentially calculates (determines) the drive amount of the substrate 15 for disposing the partial area where the focus measurement was performed at the target surface position. Then, the control device 20 performs focus leveling control of the substrate 15 by giving a command value to the substrate stage 16 based on the calculated drive amount, so that the partial area is disposed at the target surface position by the time it reaches the irradiation area 21.

[0021] On the other hand, when scanning exposure is performed by scanning the substrate 15 in the direction of the arrow R, the measurement point 30c is set to the position where the substrate 15 is exposed to light prior to the exposure of the shot area 15a in the irradiation area 21. 1 ~30c 3 In this case, the control unit 20 performs the focus measurement at the measurement point 30c. 1 ~30c 3 Based on the results (measurement values) of focus measurements sequentially performed by the focus measuring device 20, the control device 20 sequentially calculates (determines) the drive amount of the substrate 15 for disposing the partial area where the focus measurement was performed at the target surface position. Then, the control device 20 performs focus leveling control of the substrate 15 by giving a command value to the substrate stage 16 based on the calculated drive amount, so that the partial area is disposed at the target surface position by the time it reaches the irradiation area 21.

[0022] Here, in the measurement unit 17 of this embodiment, the measurement field for performing focus measurement prior to exposure in the irradiation area 21 is a plurality of measurement points (30b 1 ~30b 3 or 30c 1 ~30c 3 However, the present invention is not limited thereto, and the measurement field of view may be configured as a region (30b or 30c) extending in a direction intersecting the scanning direction (for example, the X-axis direction) as shown in FIG.

[0023] [Scanning exposure of missing shot area] In recent years, in order to improve yield, the exposure apparatus 100 performs scanning exposure not only on a complete shot area arranged in the center of the substrate 15, but also on a defective shot area arranged on the periphery (outer periphery) of the substrate 15. The complete shot area is a shot area 15a that does not include the periphery (edge) of the substrate 15 and onto which the entire pattern of the original 12 can be transferred. The defective shot area is a shot area 15a that includes the periphery (edge) of the substrate 15 and onto which only a part of the pattern of the original 12 is transferred.

[0024] In the defective shot area, the size of the overlapping portion between the measurement field of the measurement unit 17, which performs focus measurement prior to exposure in the irradiation area 21, and the substrate 15 changes successively during the scanning exposure. For example, the measurement field of a plurality of measurement points 30b 1 ~30b 3 When using the above method, the number of measurement points 30 located on the substrate changes sequentially during scanning exposure. Therefore, depending on the change in the size of the overlapping portion (e.g., the number of measurement points 30) during scanning exposure of the missing shot area, the measurement result of the focus measurement may vary significantly. In this case, the focus and leveling control of the substrate 15 cannot be performed with high accuracy, and it may be difficult to form a pattern on the missing shot area 15a with high accuracy. In addition, the peripheral portion of the substrate 15 is prone to have steps other than the steps (process steps) of the underlying pattern already formed on the substrate 15, such as steps caused by local bending of the substrate itself, steps caused by holding the substrate 15, and steps caused by foreign matter attached to the substrate 15. Therefore, such steps may also easily cause large fluctuations in the measurement result of the focus measurement, making it difficult to perform the focus and leveling control of the substrate 15 with high accuracy.

[0025] Here, the overlapping portion between the measurement field of the measurement unit 17 and the substrate 15 refers to an area in the measurement field of the measurement unit 17 where the measurement result of the focus measurement can be used, that is, an area where the measurement result of the focus measurement is valid. In the following description, the overlapping portion may be referred to as an effective area. Also, in the following description, the reference symbol 15a may be used to denote a missing shot area.

[0026] 5 is a diagram showing the scanning exposure of the defective shot area 15a in a time series. In FIG. 5, the irradiation area 21 and the measurement point 30b as the measurement field of the measurement unit 17 are shown. 1 ~30b 3 As described above, in the scanning exposure, the measurement point 30b 1 ~30b 3 5, during the scanning exposure of the defective shot area 15a, the focus measurement is performed at the measurement point 30b. 1 ~30b 3The control unit 20 performs focus measurement at the measurement point 30b in each state. 1 ~30b 3 Based on the result of focus measurement using the above, a drive amount of the substrate 15 for disposing the partial area where the focus measurement was performed at the target surface position is calculated. Then, focus leveling control of the substrate 15 is performed based on the calculated drive amount.

[0027] In State 1, measurement point 30b 1 ~30b 2 is not placed on the board, and measurement point 30b 3 Only the measurement point 30b is used as a valid measurement point. 3 Only the measurement field of the measurement unit 17 (measurement point 30b 1 ~30b 3 In this case, the control unit 20 determines the effective area at the measurement point 30b 3 Based only on the measurement result of the measurement point 30b, the driving amount of the substrate 15 in the focus leveling control is calculated. 1 is not placed on the board, and measurement point 30b 2 ~30b 3 Only the measurement point 30b is used as a valid measurement point. 2 ~30b 3 Only the measurement point 30b is an effective area in the measurement field of view of the measurement unit 17. In this case, the control unit 20 2 Add the measurement result of measurement point 30b 2 ~30b 3 The driving amount of the substrate 15 in the focus leveling control is calculated based only on the measurement result.

[0028] In State 3, measurement point 30b 1 ~30b 3 All of these are placed on the substrate, and the measurement points 30b 1 ~30b 3 All of the measurement points 30b are used as valid measurement points. 1 ~30b 3All of these become the effective area in the measurement field of view of the measurement unit 17. In this case, the control unit 20 1 The measurement results of measurement point 30b were further added. 1 ~30b 3 Based on the measurement result, the driving amount of the substrate 15 in the focus leveling control is calculated. 1 ~30b 3 Since all of the above is a valid area, processing similar to that in State 3 can be performed.

[0029] As described with reference to FIG. 5, in the scanning exposure of the defective shot area 15a, the size of the effective area (overlapped portion) in the measurement field of the measurement unit 17 changes successively as shown in FIG. 6. FIG. 6(a) shows the size 61 of the effective area in each state, and FIG. 6(b) shows the change amount 62 of the effective area size in each state (the differential value of the effective area size shown in FIG. 6(a)). When the size of the effective area changes in this way, the measurement result of the measurement unit 17 in each state changes significantly, and the driving amount of the substrate 15 calculated from the measurement result may also vary significantly. As a result, it becomes difficult to make the focus and leveling control follow the scanning of the substrate 15, and as shown in FIG. 6(c), a control residual 63 may occur in the focus and leveling control. In particular, a control residual is likely to occur in State 3 where the change amount of the effective area size is relatively large, and the control residual 63 may extend to States 4 to 5. The control residual is an error between the substrate surface and the target surface position caused by the inability of focus and leveling control to follow the scanning of the substrate 15.

[0030] Therefore, the exposure apparatus 100 of this embodiment limits the driving of the substrate 15 in the focus-leveling control during scanning exposure based on information indicating the size of the effective area in the measurement field of the measurement unit 17 (hereinafter, sometimes referred to as effective area information). For example, the control unit 20 acquires the effective area information based on the layout information of the shot area on the substrate 15, and determines a parameter value for limiting the driving of the substrate 15 in the focus-leveling control based on the acquired effective area information. Then, the control unit 20 applies the parameter value to the driving amount (provisional driving amount) of the substrate 15 calculated based on the measurement result of the measurement unit 17 in the effective area, thereby obtaining a driving amount (correction driving amount) of the substrate 15 for actually performing the focus-leveling control. By driving the substrate 15 using the correction driving amount obtained in this manner, the focus-leveling control can be performed with high accuracy.

[0031] Here, when focus measurement is performed in each of the first partial region and the second partial region in the defective shot region 15a, information (change information) indicating a change (difference) in the size of the effective region between the first partial region and the second partial region may be used as effective region information. 2 ~30b 3 The second partial region is an area where focus measurement is performed after the first partial region (after the first partial region in this embodiment) and the size of the effective region is different from that of the first partial region. For example, as shown in State 3 of FIG. 5, the second partial region is an area where focus measurement is performed after the first partial region (after the first partial region). 1 ~30b 3 In the following, an example in which change information is used as effective area information will be described.

[0032] 7 is a control block diagram for realizing the focus leveling control of this embodiment. This control block diagram shows a control system for controlling the driving of the substrate 15 in scanning exposure, and may include a target position output unit 50, a subtractor 51, a first calculation unit 52, a second calculation unit 53, a trajectory determination unit 54, a trajectory correction unit 55, an information acquisition unit 56, and a parameter determination unit 57. Each unit 50 to 57 of the control system may be provided as a component of the control unit 20.

[0033] A drive profile for scanning the substrate 15 in the scanning exposure of the shot area 15a is set in advance and stored in the target position output unit 50. The drive profile may include target position profiles for each of the X-axis direction, the Y-axis direction, and the Z-axis direction, but may include at least a target position profile of the substrate 15 (substrate stage 16) in the scanning direction (Y-axis direction). Here, the drive profile will be described as being the target position profile of the substrate 15 (substrate stage 16) in the scanning direction (Y-axis direction).

[0034] The target position output unit 50 outputs the target position of the substrate 15 (substrate stage 16) in the scanning direction based on the drive profile. The subtractor 51 calculates the deviation between the target position output from the target position output unit 50 and the current position of the substrate 15 (substrate stage 16) in the scanning direction detected by the second detector 19, and supplies the calculated deviation to the first generator 52. The first generator 52 includes, for example, a PID compensator, generates a scanning drive amount (a drive amount in the scanning direction) of the substrate 15 based on the deviation supplied from the subtractor 51, and supplies the scanning drive amount to the trajectory determination unit 54. The second generator 53 includes, for example, a PID compensator, and generates a tentative drive amount (a drive amount in the Z direction) of the substrate 15 for focus leveling control based on the measurement result of the measurement unit 17 (i.e., the surface position of the substrate 15 calculated by the processor 79 of the light receiving system 17b). The provisional driving amount for the substrate 15 generated by the second generating unit 53 is supplied to the trajectory determining unit 54.

[0035] The trajectory determination unit 54 determines (sets) a target trajectory of the substrate 15 (substrate stage 16) based on the scanning drive amount supplied from the first generation unit 52 and the provisional drive amount supplied from the second generation unit 53. The target trajectory may be understood as including a drive path in the scanning direction of the substrate 15 for scanning the substrate 15 during scanning exposure, and a drive path in the Z direction of the substrate 15 for performing focus and leveling control of the substrate 15 during scanning exposure. In addition, the trajectory correction unit 55 corrects (modifies) the provisional drive amount (Z direction) of the substrate 15 in the target trajectory determined by the trajectory determination unit 54, using parameter values ​​determined by a parameter determination unit 57 described later. This makes it possible to determine the drive amount of the substrate 15 used in the actual focus and leveling control (drive amount in the Z direction, hereinafter sometimes referred to as a corrected drive amount). Then, the trajectory correction unit 55 generates a drive command value for the substrate 15 (substrate stage 16) based on the target trajectory of the substrate 15 including the corrected drive amount, and controls the drive of the substrate 15 (substrate stage 16) using the drive command value.

[0036] The information acquisition unit 56 acquires (calculates) effective area information based on the target position of the substrate 15 (substrate stage 16) output from the target position output unit 50 and the layout information of the shot area 15a, and supplies the acquired effective area information to the parameter determination unit 57. The effective area information may be information indicating a change in the size of the effective area between the previous focus measurement and the current focus measurement (for example, a change in the size of the effective area between the first partial area and the second partial area described above). The parameter determination unit 57 determines a parameter value for limiting the drive of the substrate 15 in the focus leveling control based on the effective area information supplied from the information acquisition unit 56, and supplies the determined parameter value to the trajectory correction unit 55. Thereby, the trajectory correction unit 55 can correct the provisional drive amount of the substrate 15 by the parameter value and determine the corrected drive amount.

[0037] Here, the parameter value determined by the parameter determination unit 57 will be described. The parameter value can be determined as a coefficient (in other words, a gain) to be multiplied by the provisional drive amount of the substrate 15 so that the drive of the substrate 15 is restricted (for example, the drive of the substrate 15 is restricted more severely) as the change in the size of the effective area increases. For example, the parameter value can be expressed by "α×(ΔS / ΔA)" as shown in the following formula (1). "ΔS / ΔA" in formula (1) is a first coefficient to be multiplied by the provisional drive amount. "ΔA" indicates the change in the size of the effective area, and "ΔS" indicates the sampling interval of the focus measurement, that is, the interval between a plurality of partial areas where the focus measurement is performed (for example, the interval between the first partial area and the second partial area). That is, the parameter value can be determined using the reciprocal of the change ΔA in the size of the effective area. More specifically, the parameter value can be determined using the reciprocal of a value indicating the change ΔA in the effective area relative to the sampling interval ΔS. Furthermore, "α" in formula (1) is a second coefficient (weight) multiplied by the provisional drive amount to adjust the drive amount (i.e., the correction drive amount) of the substrate 15. Details will be described later in the second embodiment, but the second coefficient α can be determined based on the drive tendency of the substrate 15 in the focus leveling control between the previous time and the current time (more specifically, a change in the drive tendency or a difference in the drive tendency). For example, the second coefficient α can be determined based on a change in the drive tendency of the substrate 15 obtained from the measurement result of the focus measurement in the second partial region relative to the drive tendency of the substrate 15 obtained from the measurement result of the focus measurement in the first partial region. The drive tendency of the substrate 15 can include the direction in which the substrate 15 is driven (drive direction). Corrected drive amount = α × (ΔS / ΔA) × provisional drive amount (1)

[0038] As described above, the exposure apparatus 100 of this embodiment determines a parameter value for limiting the driving of the substrate 15 in the focus-leveling control based on the effective area information during the scanning exposure of the shot area 15a (e.g., a defective shot area). Then, the focus-leveling control of the substrate 15 is performed based on the driving amount (corrected driving amount) of the substrate 15 calculated using the determined parameter value. This improves the tracking of the focus-leveling control with respect to the scanning of the substrate 15, and the focus-leveling control can be performed with high accuracy, so that the control residual generated in the focus-leveling control can be reduced as shown in FIG. 8. FIG. 8 is a diagram showing the control residual generated in the focus-leveling control, and shows the control residual 63 when the parameter value of this embodiment is not applied and the control residual 63a when the parameter value of this embodiment is applied.

[0039] <Second embodiment> A second embodiment of the present invention will be described. In this embodiment, a process for determining parameter values ​​during scanning exposure of the shot area 15a will be described. Note that the second embodiment basically follows on from the first embodiment, and the configuration of the exposure apparatus 100 and the contents of the exposure process are the same as those described in the first embodiment.

[0040] For example, assume that the driving tendency of the substrate 15 obtained from the measurement result of the focus measurement this time (e.g., the second partial region) is similar to the driving tendency of the substrate 15 obtained from the result of the focus measurement last time (e.g., the first partial region). The driving tendency of the substrate 15 may be understood as, for example, the direction (Z-axis direction, ωX direction, ωY direction) in which the substrate 15 should be driven in focus-leveling control. As an example, assume that the driving tendency of the substrate 15 last time was a tilt in the +ωX direction, and the driving tendency of the substrate 15 this time is also a tilt in the +ωX direction. In this case, if the parameter value is changed according to the change in the size of the effective area between the last time and this time, the current focus-leveling control may become insufficient, which may result in a decrease in the transfer accuracy of the pattern onto the substrate.

[0041] Therefore, in this embodiment, it is determined whether the provisional drive amount (second drive amount) obtained from the measurement result of the focus measurement this time (for example, the second partial region) has the same drive tendency as the provisional drive amount (first drive amount) obtained from the measurement result of the focus measurement last time (for example, the first partial region). If they have the same drive tendency, the parameter value is determined so that the restriction on the drive of the substrate 15 in the focus leveling control is relaxed this time (second partial region) compared to the last time (first partial region). For example, by changing the second coefficient α, the parameter value can be determined so that the restriction on the drive of the substrate 15 is relaxed. On the other hand, if they have different drive tendencies, the parameter value is determined using the above-mentioned formula (1) without changing the second coefficient α.

[0042] 9 is a flowchart showing a process of determining parameter values ​​during scanning exposure of the shot area 15a. Each step in FIG. 9 can be performed by the control unit 20 (for example, the parameter determination unit 57).

[0043] In step S10, the control unit 20 judges whether or not a parameter value has been changed in the focus leveling control based on the measurement result of the previous focus measurement. If the parameter value has been changed in the previous focus leveling control, the process proceeds to step S11. On the other hand, if the parameter value has not been changed, the process proceeds to step S14, where the parameter value is set using the formula (1) as described in the first embodiment. Next, in step S11, the control unit 20 judges whether or not the driving tendency of the substrate 15 obtained from the measurement result of the current focus measurement is similar to the driving tendency of the substrate 15 obtained from the measurement result of the previous focus measurement. Examples of cases in which the driving tendency is judged to be similar include a case where the change in the driving amount of the substrate 15 is within an allowable range, or a case where the direction in which the substrate 15 is driven is the same. If the driving tendency is similar, the process proceeds to step S12, and if the driving tendency is different, the process proceeds to step S14.

[0044] In step S12, the control unit 20 changes (resets) the second coefficient α (weight) so that the restriction on the drive of the substrate 15 is relaxed. Specifically, as shown in the following formula (2), the second coefficient α can be calculated based on the ratio of the drive amount of the substrate 15 this time (for example, the provisional drive amount) to the drive amount of the substrate 15 last time. For example, when the drive amount of the substrate 15 this time increases with respect to the drive amount of the substrate 15 last time, the second coefficient α becomes 1 or more, so that the parameter value of the formula (1) can be increased. On the other hand, when the drive amount of the substrate 15 this time decreases with respect to the drive amount of the substrate 15 last time, the second coefficient α becomes less than 1, so that the parameter value of the formula (1) can be decreased. Next, in step S13, the control unit 20 uses the second coefficient α determined in step S12 to determine the parameter value using the formula (1) by the method described above in the first embodiment. Second coefficient α = current drive amount / previous drive amount (2)

[0045] In step S14, the control unit 20 determines whether the size of the effective area has changed since the previous focus measurement based on the effective area information. If the size of the effective area has changed, the process proceeds to step S15, where the control unit 20 uses the second coefficient α used in the previous focus leveling control to determine the parameter value using equation (1) by the method described above in the first embodiment. On the other hand, if the size of the effective area has not changed, the process proceeds to step S16, where the control unit 20 determines the parameter value used in the previous focus leveling control as the parameter value to be applied to the current focus leveling control.

[0046] FIG. 10 shows the effect of determining the parameter value by changing the second coefficient α in steps S12 to S13 described above. FIG. 10(a) shows the size of the effective area in each state (see FIG. 5), and FIG. 10(b) shows the change in the size of the effective area in each state (the differential value of the size of the effective area shown in FIG. 10(a)). FIG. 10(c) shows the parameter values ​​used in each state, and FIG. 10(d) shows the control residual generated in the focus and leveling control in each state. As shown in FIG. 10(c), the parameter value 64a when the second coefficient α is changed in steps S12 to S13 can be reduced compared to the parameter value 64 when the second coefficient α is not changed. That is, the restriction on the drive of the substrate 15 can be relaxed. This can improve the follow-up of the focus and leveling control to the scanning of the substrate 15. Therefore, as shown in FIG. 10(d), the control residual 63b when the second coefficient α is changed can be reduced more than the control residual 63 when the second coefficient α is not changed.

[0047] As described above, in this embodiment, the parameter value is determined based on the drive tendency of the substrate 15 obtained from the measurement result of the previous focus measurement and the drive tendency obtained from the measurement result of the current focus measurement. This makes it possible to avoid a problem of excessively restricting the drive of the substrate 15 in the focus leveling control and to appropriately restrict the drive of the substrate 15 in the focus leveling control.

[0048] <Third embodiment> A third embodiment of the present invention will be described. In this embodiment, a method for performing focus leveling control with even greater accuracy will be described. Note that the third embodiment basically follows on from the first embodiment, and the configuration of the exposure apparatus 100 and the contents of the exposure process are as described in the first embodiment. Also, the second embodiment may be applied to this embodiment.

[0049] Fig. 11 is a flowchart showing a process for determining a target trajectory of the substrate 15 during scanning exposure of the shot area 15a. Each step in Fig. 11 can be performed by the control unit 20 (for example, the second generation unit 53, the trajectory determination unit 54, and the trajectory correction unit 55).

[0050] In step S20, the control unit 20 calculates (generates) a drive amount of the substrate 15 for focus leveling control based on the measurement result of the focus measurement in the effective area. The drive amount of the substrate 15 calculated in this step S20 may be a drive amount (provisional drive amount) before correction using the parameter value, or may be a drive amount (corrected drive amount) after correction using the parameter value. Next, in step S21, the control unit 20 judges whether or not the drive amount of the substrate 15 calculated in step S20 exceeds an allowable range. The allowable range specifies at least an upper limit value for restricting the drive of the substrate 15, and may be set so as to change according to the change in the size of the effective area. If the drive amount of the substrate 15 exceeds the allowable range, the process proceeds to step 22. On the other hand, if the drive amount of the substrate 15 does not exceed the allowable range, the drive amount calculated in step S21 is determined as the drive amount of the substrate 15 to be used in the actual focus leveling control, and the process ends.

[0051] In step S22, the control unit 20 recalculates the drive amount of the substrate 15 for focus leveling control. Specifically, the control unit 20 recalculates the drive amount of the substrate 15 based on the measurement result of the focus measurement in the remaining part of the effective area where the focus measurement was performed this time, excluding the changed part where the size of the effective area has changed since the previous focus measurement. Next, in step S23, the control unit 20 judges whether the drive amount of the substrate 15 recalculated in step S22 exceeds the allowable range. If the recalculated drive amount of the substrate 15 exceeds the allowable range, the process proceeds to step S24, where the control unit 20 corrects the drive amount of the substrate 15 so that it falls within the allowable range, and determines the target trajectory of the substrate 15 based on the corrected drive amount. For example, the control unit 20 may set (determine) the drive amount of the substrate 15 used in the actual focus leveling control to the upper limit value of the allowable range. On the other hand, if the recalculated drive amount of the substrate 15 does not exceed the allowable range, the process proceeds to step S25, where the control unit 20 determines the target trajectory based on the recalculated drive amount of the substrate 15.

[0052] As described above, in this embodiment, when the drive amount of the substrate 15 exceeds the allowable range, the drive amount of the substrate 15 is recalculated based on the measurement results of the focus measurement in the remaining part of the effective area, excluding the part where the size of the effective area has changed. This allows the focus leveling control to accurately follow the scanning of the substrate 15, making it possible to form a pattern on the substrate with high accuracy.

[0053] <Fourth embodiment> A fourth embodiment of the present invention will be described. In this embodiment, an exposure method using the above-mentioned exposure apparatus 100 will be described. Note that the fourth embodiment basically follows on from the first embodiment, and the configuration of the exposure apparatus 100 and the contents of the exposure process are as described in the first embodiment. Also, the second and third embodiments may be applied to this embodiment.

[0054] 12 is a flowchart showing a method for exposing the substrate 15. Each step in FIG.

[0055] In step S30, the control unit 20 uses a conveying hand (not shown) to carry the substrate 15 onto the substrate stage 16, and causes the substrate stage 16 to hold the substrate 15. In step S31, the control unit 20 performs pre-measurement and correction for the global alignment performed in step S35. For example, the control unit 20 measures and corrects the amount of deviation such as a rotation error of the substrate 15 using a low-magnification field alignment microscope (not shown) so that the substrate 15 falls within the measurement range of a high-magnification field alignment microscope (not shown) used in the global alignment. Next, in step S32, the control unit 20 uses the measurement unit 17 to measure the surface positions of the substrate 15 at a plurality of measurement positions. From the measurement results, the control unit 20 calculates and corrects the overall tilt (global tilt) of the substrate 15. Next, in step S33, the control unit 20 stores the pattern structure of the surface of the shot region 15a on the substrate 15 as a correction pattern offset. If a pattern offset previously obtained exists, a pre-focus measurement is performed using a sample shot for obtaining a confirmation pattern offset, and the confirmation pattern offset is obtained.

[0056] In step S34, the control unit 20 calculates correction values ​​for the inclination of the projection lens, the field curvature, and the like, using a light amount sensor and a reference mark (not shown) on the substrate stage 16 and a reference plate (not shown) on the original stage 13. Specifically, the light amount sensor measures the change in the light amount of the exposure light when the substrate stage 16 is scanned in the XYZ directions. From the change in the light amount of the light amount sensor, the control unit 20 measures the amount of deviation of the reference mark on the substrate stage 16 relative to the reference plate on the original stage 13. Next, in step S35, the control unit 20 measures the alignment mark on the substrate 15 using a high-magnification field alignment microscope (not shown), and calculates the amount of deviation of the entire substrate 15 and the amount of deviation common to each shot area 15a. In order to precisely measure the alignment mark, it is preferable that the contrast of the alignment mark is at the best contrast position. The measurement of the best contrast position can be performed using a focus measurement device dedicated to the alignment microscope (not shown) and the alignment microscope. Specifically, the substrate stage 16 is driven to a predetermined height, and the contrast is measured by the alignment microscope while the height is measured by the focus measurement device. This is repeated multiple times by changing the height of the substrate stage 16. At this time, the contrast measurement results corresponding to each height are associated with the height measurement results and stored in the control unit 20. From the multiple contrast measurement results obtained, the position with the highest contrast is calculated and determined as the best contrast position.

[0057] In step S36, the control unit 20 performs scanning exposure while measuring the surface position of the shot area 15a to be exposed in real time with the measurement unit 17 and performing focus and leveling control of the substrate 15 (substrate stage 16). The scanning exposure in step S36 is performed for each of the multiple shot areas 15a on the substrate 15. In addition, in the scanning exposure in step S36, as described in the first embodiment, a parameter value for limiting the driving of the substrate 15 in the focus and leveling control may be set sequentially according to a change in the size of the effective area in which the focus measurement is performed. In addition, in step S36, the parameter value determination process described in the second embodiment and / or the method described in the third embodiment may be applied. When scanning exposure has been performed for all the shot areas 15a of the substrate 15, the process proceeds to step S37, and the control unit 20 carries the substrate 15 out of the substrate stage 16 using a transport hand (not shown).

[0058] <Embodiments of the method for manufacturing an article> The method for manufacturing an article according to an embodiment of the present invention is suitable for manufacturing an article such as a microdevice such as a semiconductor device or an element having a fine structure. The method for manufacturing an article according to this embodiment includes a step of forming a latent image pattern on a photosensitive agent applied to a substrate using the above-mentioned exposure apparatus (a step of exposing the substrate) and a step of developing (processing) the substrate on which the latent image pattern has been formed in this step. Furthermore, this manufacturing method includes other well-known steps (oxidation, film formation, deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, etc.). The method for manufacturing an article according to this embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of the article compared to conventional methods.

[0059] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0060] 11: illumination optical system, 12: original, 13: original stage, 14: projection optical system, 15: substrate, 16: substrate stage, 17: measurement unit, 20: control unit, 100: exposure apparatus

Claims

1. An exposure apparatus that performs scanning exposure on a shot area of ​​a substrate using exposure light, a measurement unit that measures a surface position of the shot area within a measurement field of view prior to exposure of the shot area with the exposure light; a control unit that performs focus and leveling control of the substrate based on a measurement result of the measurement unit in an overlapping portion between the measurement field of view and the shot area during the scanning exposure; Equipped with The exposure apparatus, characterized in that the control unit determines a parameter value for limiting the driving of the substrate in the focus leveling control based on change information indicating a change in size of the overlapping portion during the scanning exposure.

2. the shot area includes a first partial area in which the measurement of a surface position is performed by the measurement unit, and a second partial area in which the measurement of a surface position is performed by the measurement unit after the measurement of the first partial area, The exposure apparatus of claim 1, wherein the control unit determines the parameter value used in the focus leveling control for the second partial region based on information indicating a change in size of the overlapping portion between the first partial region and the second partial region as the change information.

3. 3. The exposure apparatus according to claim 2, wherein the surface position of the second partial area is measured by the measurement unit after the surface position of the first partial area is measured.

4. the measurement unit includes a plurality of measurement points each for measuring a surface position within the measurement field of view, 4. The exposure apparatus according to claim 2, wherein the change information includes information indicating a difference between the number of measurement points arranged in the first partial area and the number of measurement points arranged in the second partial area as the change.

5. 5. The exposure apparatus according to claim 2, wherein the control unit determines the parameter value so that the larger the change is, the more the driving of the substrate in the focus leveling control is restricted.

6. 6. The exposure apparatus according to claim 2, wherein the control unit determines the parameter value as a coefficient by which to multiply a drive amount of the substrate calculated from the measurement result of the measurement unit.

7. 7. The exposure apparatus according to claim 6, wherein the control unit determines the parameter value using an inverse of the change.

8. the measurement unit measures a surface position within the measurement field at predetermined intervals during the scanning exposure, 7. The exposure apparatus according to claim 6, wherein the control unit determines the parameter value using an inverse number of a value indicating the change with respect to the predetermined interval.

9. the control unit determines the parameter value based on a change in a drive tendency of the substrate obtained from a measurement result of the measurement unit in the second partial region relative to a drive tendency of the substrate obtained from a measurement result of the measurement unit in the first partial region; 9. The exposure apparatus according to claim 6, wherein the drive tendency of the substrate includes a drive direction of the substrate.

10. 10. The exposure apparatus according to claim 2, wherein, when the drive amount of the substrate calculated from the measurement results of the measurement unit exceeds an allowable range, the control unit recalculates the drive amount of the substrate based on a portion of the overlapping portion obtained by removing a portion of the overlapping portion that has changed since the previous measurement by the measurement unit.

11. 11. The exposure apparatus according to claim 1, wherein the shot area is a missing shot area that is arranged on the periphery of the substrate and to which only a part of a pattern of an original is transferred.

12. an exposure step of exposing a substrate using the exposure apparatus according to any one of claims 1 to 11; a processing step of processing the substrate exposed in the exposure step, A method for manufacturing an article, comprising manufacturing an article from the substrate processed in the processing step.

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