Method, adjustment method, and exposure device

Abstract

This method includes: causing measurement light to enter a spatial light modulator in which a plurality of tiltable mirrors in a first state are disposed; receiving light from the spatial light modulator; and evaluating the first state on the basis of the relationship between the received light and a reference position.

Description

method, adjustment method, and exposure apparatus - Patents.com

[0001] The present invention relates to a method, an adjustment method, and an exposure apparatus.

[0002] In the lithography process for manufacturing electronic devices (microdevices) such as liquid crystal or organic EL display panels and semiconductor elements (integrated circuits, etc.), step-and-repeat projection exposure apparatus (so-called steppers) or step-and-scan projection exposure apparatus (so-called scanning steppers (also called scanners)) are used. This type of exposure apparatus projects and exposes a mask pattern for the electronic device onto a photosensitive layer applied to the surface of an exposed substrate (hereinafter simply referred to as substrate), such as a glass substrate, semiconductor wafer, printed wiring board, or resin film.

[0003] Because it takes time and money to fabricate a mask substrate on which the mask pattern is fixedly formed, an exposure apparatus is known that uses a spatial light modulator (variable mask pattern generator) such as a digital mirror device (DMD) in which a large number of micromirrors that are slightly displaced are regularly arranged instead of a mask substrate (see, for example, Patent Document 1). In the exposure apparatus disclosed in Patent Document 1, for example, illumination light obtained by mixing light from a laser diode (LD) with a wavelength of 375 nm and light from an LD with a wavelength of 405 nm through a multimode fiber bundle is irradiated onto the digital mirror device (DMD), and the reflected light from each of a large number of tilt-controlled micromirrors is projected onto the substrate for exposure via an imaging optical system and a microlens array.

[0004] Japanese Patent Application Laid-Open No. 2019-23748

[0005] In an exposure apparatus using a DMD, a pattern is generated by tilting the micromirrors provided on the DMD, and the pattern is imparted to the illumination light, so it is desirable to know the exact tilt angle of the micromirrors.

[0006] According to a first aspect of the disclosure, a method includes directing measurement light into a spatial light modulator having a plurality of tiltable mirrors arranged in a first state, receiving light from the spatial light modulator, and evaluating the first state based on a relationship between the received light and a reference position.

[0007] According to a second aspect of the disclosure, an adjustment method is a method for adjusting an optical device including a spatial light modulator, and includes adjusting, based on the first state evaluated by the above-described method, at least one of the position or angle of at least one optical element in an illumination unit that irradiates illumination light onto the spatial light modulator or a projection unit that projects light from the spatial light modulator, the installation state of the spatial light modulator, and the tilt angle of the on-state of multiple tiltable mirrors of the spatial light modulator.

[0008] According to a third aspect of the disclosure, a method includes: directing measurement light into a spatial light modulator having a plurality of tiltable mirrors in a first state; receiving light from the spatial light modulator; and evaluating the first state based on a relationship between the received light and a reference position, wherein the light is diffracted light; evaluating the first state includes evaluating the first state based on an intensity distribution of the diffracted light and the reference position; the plurality of tiltable mirrors in the first state are a plurality of tiltable mirrors tilted at a first angle; and evaluating the first state includes calculating the first angle.

[0009] According to a fourth aspect of the disclosure, an adjustment method is a method for adjusting an optical device including a spatial light modulator, and includes adjusting, based on the first angle calculated by the above method, at least one of the position or angle of at least one optical element in an illumination unit that irradiates illumination light onto the spatial light modulator or a projection unit that projects light from the spatial light modulator, the installation state of the spatial light modulator, and the tilt angle in the on state of multiple tiltable mirrors of the spatial light modulator.

[0010] According to a fifth aspect of the disclosure, an exposure apparatus includes a spatial light modulator including a plurality of tiltable mirrors arranged two-dimensionally, an illumination unit that irradiates illumination light onto the spatial light modulator, a projection unit that irradiates an exposure target with light from the spatial light modulator, an acquisition device that acquires the intensity distribution of the light from the spatial light modulator, and a control device, wherein the control device adjusts at least one of the position or angle of at least one optical element in the illumination unit or the projection unit, the position or angle of the spatial light modulator, and the tilt angle of the plurality of tiltable mirrors in an on state based on the intensity distribution.

[0011] The configurations of the embodiments described below may be modified as appropriate, and at least a portion of the configuration may be replaced with other components. Furthermore, components that are not particularly limited in terms of their placement may be placed in any position that can achieve their function, not limited to the placement disclosed in the embodiments.

[0012] FIG. 1 is a perspective view showing an outline of the external configuration of an exposure apparatus according to a first embodiment. FIG. 2 is a diagram showing an example of the arrangement of DMD projection areas projected onto a substrate by each projection unit of a plurality of exposure modules. FIG. 3 is a diagram explaining the state of spliced ​​exposure by each of four specific projection areas in FIG. 2. FIG. 4 is an optical layout diagram showing the specific configuration of two exposure modules aligned in the X-axis direction (scanning exposure direction) as viewed in the XZ plane. FIG. 5(A) is a plan view showing the arrangement of micromirrors provided in a DMD, FIG. 5(B) is a diagram showing the DMD when powered off, FIG. 5(C) is a diagram explaining the micromirrors in the on state, and FIG. 5(D) is a diagram explaining the micromirrors in the off state. FIG. 6 is a diagram explaining in detail the imaging state of the DMD micromirrors by the projection unit. FIG. 7 is a diagram explaining the optical path difference in a DMD. FIG. 8(A) is a diagram showing the schematic configuration of a measurement apparatus according to a first embodiment, and FIG. 8(B) is a diagram showing another schematic configuration of the measurement apparatus. FIG. 9 is a diagram showing an example of a pattern generated by the DMD when measuring the tilt angle of the micromirror. FIG. 10 is a diagram showing simulation results of the intensity distribution in the pupil of diffracted light generated when a measurement light is irradiated onto an area in which the pattern shown in FIG. 9 is generated, when the tilt angle of the micromirror is a standard value. FIG. 11 is a diagram showing an example of a pattern generated by the DMD when setting a reference position. FIG. 12 is a diagram showing simulation results of the intensity distribution in the pupil of diffracted light generated when a measurement light is irradiated onto an area in which the pattern shown in FIG. 11 is generated. FIG. 13 is a diagram showing simulation results of the intensity distribution in the pupil of diffracted light obtained when a measurement light is irradiated onto an area in which the pattern shown in FIG. 9 is generated, when the θy′ angle of the micromirror in the on state deviates by +0.5° from the standard value. FIG. 14 is a diagram showing simulation results of the intensity distribution in the pupil of diffracted light obtained when a measurement light is irradiated onto an area in which the pattern shown in FIG. 9 is generated, when the θy′ angle of the micromirror in the on state deviates by −0.5° from the standard value.FIG. 15 shows the simulation results of the intensity distribution in the pupil of diffracted light obtained when a measurement beam is irradiated onto an area where the pattern shown in FIG. 9 is generated, when the θz angle of the micromirror in the on-state deviates by +2° from the standard value. FIG. 16 shows the simulation results of the intensity distribution in the pupil of diffracted light obtained when a measurement beam is irradiated onto an area where the pattern shown in FIG. 9 is generated, when the θz angle of the micromirror in the on-state deviates by -2° from the standard value. FIG. 17 shows an example of an image of the intensity distribution in the pupil of diffracted light from a pattern generated by a DMD. FIGS. 18A and 18B show other examples of patterns generated by a DMD when measuring the tilt angle of a micromirror in the on-state. FIG. 19 shows the simulation results of the intensity distribution in the pupil of diffracted light generated by the pattern shown in FIG. 18A. FIG. 20 shows the simulation results of the intensity distribution in the pupil of diffracted light generated by the pattern shown in FIG. 18B. FIG. 21 is a diagram schematically showing a configuration for measuring the tilt angle of a micromirror in the on-state in an exposure apparatus. FIG. 22 is a diagram showing a schematic configuration of an optical measurement unit provided in a calibration reference unit attached to an end of the substrate holder of the exposure apparatus shown in FIG. 1. FIG. 23(A) is a diagram showing an example of a pattern generated by the DMD by the pattern control unit in the second embodiment, and FIGS. 23(B) to 23(D) are diagrams showing simulation results of the intensity distribution of diffracted light generated by the pattern shown in FIG. 23(A). FIGS. 24(A) to 24(C) are diagrams for explaining a method for calculating the center position of the intensity distribution of diffracted light executed by the calculation unit in the second embodiment. FIGS. 25(A) to 25(C) are diagrams for explaining a method for calculating the center position of the intensity distribution of diffracted light executed by the calculation unit in the second embodiment. FIGS. 26(A) and 26(B) are diagrams showing another example of a pattern generated by the DMD by the pattern control unit in the second embodiment. FIGS. 27(A) to 27(C) are diagrams showing simulation results of the intensity distribution of diffracted light generated by the pattern shown in FIG. 26(A). 28A to 28C are diagrams showing the results of a simulation of the intensity distribution of diffracted light generated by the pattern shown in FIG. 26B.Fig. 29 is a graph showing the degree of asymmetry of the intensity distribution. Figs. 30(A) and 30(B) are diagrams showing another example of a configuration for measuring the tilt angle of a micromirror in an exposure apparatus. Figs. 31(A) and 31(B) are diagrams showing another example of a pattern generated by a DMD when measuring the tilt angle of a micromirror. Figs. 32(A) and 32(B) are diagrams showing another example of a DMD configuration.

[0013] First Embodiment A pattern exposure apparatus (hereinafter simply referred to as exposure apparatus) according to a first embodiment will be described with reference to the drawings.

[0014] [Overall Configuration of Exposure Apparatus] Figure 1 is a perspective view showing an outline of the external configuration of an exposure apparatus EX according to the first embodiment. The exposure apparatus EX is an apparatus that projects exposure light, the intensity distribution of which is dynamically modulated in space by a spatial light modulator (SLM), onto an exposed substrate to form an image. Examples of spatial light modulators include liquid crystal elements, digital micromirror devices (DMDs), and magneto-optic spatial light modulators (MOSLMs). The exposure apparatus EX according to this embodiment is equipped with a DMD chip that includes a DMD 10 as the spatial light modulator.

[0015] In a specific embodiment, the exposure apparatus EX is a step-and-scan projection exposure apparatus (scanner) that exposes a rectangular (square) glass substrate used in display devices (flat panel displays) and the like. The glass substrate is a substrate P for flat panel displays, with at least one side or diagonal length of 500 mm or more and a thickness of 1 mm or less. The exposure apparatus EX exposes a projected image of a pattern created by a DMD onto a photosensitive layer (photoresist) formed with a constant thickness on the surface of the substrate P. The substrate P is unloaded from the exposure apparatus EX after exposure and is sent to a predetermined process step (film formation step, etching step, plating step, etc.) after a development step.

[0016] The exposure apparatus EX is equipped with a stage device that includes a pedestal 2 placed on active vibration isolation units 1a, 1b, 1c, and 1d (1d not shown), a surface plate 3 placed on the pedestal 2, an XY stage 4A that is movable two-dimensionally on the surface plate 3, a substrate holder 4B that holds a substrate P on a plane by suction on the XY stage 4A, and laser length measurement interferometers (hereinafter simply referred to as interferometers) IFX, IFY1 to IFY4 that measure the two-dimensional movement position of the substrate holder 4B (substrate P). Such a stage device is disclosed, for example, in U.S. Patent Publication No. 2010 / 0018950 and U.S. Patent Publication No. 2012 / 0057140.

[0017] In FIG. 1 , the XY plane of the Cartesian coordinate system XYZ is set parallel to the flat surface of the stage device's base 3, and the XY stage 4A is set to be able to translate within the XY plane. In this embodiment, the direction parallel to the X axis of the coordinate system XYZ is set as the scanning movement direction of the substrate P (XY stage 4A) during scan exposure. The movement position of the substrate P in the X-axis direction is sequentially measured by the interferometer IFX, and the movement position in the Y-axis direction is sequentially measured by at least one (preferably two or more) of the four interferometers IFY1 to IFY4. The substrate holder 4B is configured to be able to move slightly relative to the XY stage 4A in the Z-axis direction, which is perpendicular to the XY plane, and to be able to tilt slightly in any direction relative to the XY plane, thereby actively adjusting the focus and leveling (parallelism) between the surface of the substrate P and the imaging plane of the projected pattern. Furthermore, the substrate holder 4B is configured to be able to rotate slightly (θz rotation) about an axis parallel to the Z axis in order to actively adjust the tilt of the substrate P in the XY plane.

[0018] The exposure apparatus EX further includes an optical table 5 that holds multiple exposure (drawing) modules MU(A), MU(B), and MU(C), and main columns 6a, 6b, 6c, and 6d (6d is not shown) that support the optical table 5 from the pedestal 2. Each of the multiple exposure modules MU(A), MU(B), and MU(C) is attached to the +Z direction side of the optical table 5. The multiple exposure modules MU(A), MU(B), and MU(C) may be attached to the optical table 5 individually, or may be attached to the optical table 5 in a state where two or more exposure modules are connected to each other to increase rigidity. Each of the multiple exposure modules MU(A), MU(B), and MU(C) includes an illumination unit ILU that is attached to the +Z direction side of the optical table 5 and that receives illumination light from an optical fiber unit FBU, and a projection unit PLU that is attached to the −Z direction side of the optical table 5 and has an optical axis parallel to the Z axis. Furthermore, each of the exposure modules MU(A), MU(B), and MU(C) includes a DMD 10 as a modulation unit that reflects illumination light from the illumination unit ILU in the -Z direction and makes it incident on the projection unit PLU. The detailed configuration of the exposure module consisting of the illumination unit ILU, DMD 10, and projection unit PLU will be described later.

[0019] Multiple alignment systems (microscopes) ALG that detect alignment marks formed at multiple predetermined positions on the substrate P are attached to the -Z direction side of the optical surface plate 5 of the exposure apparatus EX. Furthermore, a calibration reference unit CU for calibration is provided at the -X direction end of the substrate holder 4B. Calibration includes at least one of confirming the relative positional relationship in the XY plane of the detection fields of the alignment systems ALG (calibration), confirming the baseline error between the projection positions of the pattern images projected from the projection units PLU of each of the exposure modules MU(A), MU(B), and MU(C) and the positions of the detection fields of the alignment systems ALG (calibration), and confirming the position and image quality of the pattern images projected from the projection units PLU. Note that, although some of the modules are not shown in FIG. 1 , in this embodiment, each of the exposure modules MU(A), MU(B), and MU(C) includes, for example, nine modules arranged at regular intervals in the Y-axis direction, although the number of modules may be more or less than nine. In addition, although three rows of exposure modules are arranged in the X-axis direction in FIG. 1, the number of rows of exposure modules arranged in the X-axis direction may be two or less, or may be four or more.

[0020] 2 is a diagram showing an example of the arrangement of projection areas IAn of the DMD 10 projected onto the substrate P by the projection units PLU of each of the exposure modules MU(A), MU(B), and MU(C), and the Cartesian coordinate system XYZ is set in the same way as in FIG. 1. The projection areas IAn can be said to be the irradiation ranges (light irradiation area groups) of the illumination light that is reflected by the multiple micromirrors Ms of the DMD 10 and directed onto the substrate P by the projection units PLU. In this embodiment, the first row of exposure modules MU(A), the second row of exposure modules MU(B), and the third row of exposure modules MU(C), which are arranged spaced apart in the X-axis direction, each consist of nine modules lined up in the Y-axis direction. Exposure module MU(A) is made up of nine modules MU1 to MU9 arranged in the +Y direction, exposure module MU(B) is made up of nine modules MU10 to MU18 arranged in the -Y direction, and exposure module MU(C) is made up of nine modules MU19 to MU27 arranged in the +Y direction. Modules MU1 to MU27 all have the same configuration, and when exposure module MU(A) and exposure module MU(B) are arranged face to face in the X-axis direction, exposure module MU(B) and exposure module MU(C) are arranged back to back in the X-axis direction.

[0021] 2, the shape of the projection areas IA1, IA2, IA3, ..., IA27 (sometimes referred to as IAn, where n is 1 to 27) by each of the modules MU1 to MU27 is, as an example, a rectangle extending in the Y-axis direction with an aspect ratio of approximately 1:2. In this embodiment, as the substrate P is scanned and moved in the +X direction, patch exposure is performed at the -Y direction end of each of the first row of projection areas IA1 to IA9 and the +Y direction end of each of the second row of projection areas IA10 to IA18. Then, areas on the substrate P that were not exposed by each of the first and second rows of projection areas IA1 to IA18 are patch exposure by each of the third row of projection areas IA19 to IA27. The center point of each of the projection areas IA1 to IA9 in the first column is located on a line k1 parallel to the Y axis, the center point of each of the projection areas IA10 to IA18 in the second column is located on a line k2 parallel to the Y axis, and the center point of each of the projection areas IA19 to IA27 in the third column is located on a line k3 parallel to the Y axis. The distance between lines k1 and k2 in the X axis direction is set to a distance XL1, and the distance between lines k2 and k3 in the X axis direction is set to a distance XL2.

[0022] Here, assuming that the joint portion between the −Y direction end of projection area IA9 and the +Y direction end of projection area IA10 is OLa, the joint portion between the −Y direction end of projection area IA10 and the +Y direction end of projection area IA27 is OLb, and the joint portion between the +Y direction end of projection area IA8 and the −Y direction end of projection area IA27 is OLc, the state of the joint exposure will be described with reference to Figure 3. In Figure 3, the Cartesian coordinate system XYZ is set to be the same as in Figures 1 and 2, and the coordinate system X'Y' in projection areas IA8, IA9, IA10, and IA27 (and all other projection areas IAn) is set to be inclined at an angle θk (0°<θk<90°) with respect to the X and Y axes (lines k1 to k3) of the Cartesian coordinate system XYZ. That is, the areas (light irradiation areas) on the substrate P onto which the illumination light reflected by the many micromirrors of the DMD 10 is projected are arranged two-dimensionally along the X'-axis and Y'-axis.

[0023] The circular area encompassing each of the projection areas IA8, IA9, IA10, and IA27 (and all other projection areas IAn) in FIG. 3 represents the circular image field PLf' of the projection unit PLU. At the joint OLa, the projected image (light irradiation area) of the micromirrors arranged diagonally (at an angle θk) at the end of the projection area IA9 in the -Y' direction is set to overlap with the projected image (light irradiation area) of the micromirrors arranged diagonally (at an angle θk) at the end of the projection area IA10 in the +Y' direction. At the joint OLb, the projected image (light irradiation area) of the micromirrors arranged diagonally (at an angle θk) at the end of the projection area IA10 in the -Y' direction is set to overlap with the projected image (light irradiation area) of the micromirrors arranged diagonally (at an angle θk) at the end of the projection area IA27 in the +Y' direction. Similarly, at the joint OLc, the projected image (light irradiation area) of the micromirror arranged diagonally (at an angle θk) at the end of the +Y' direction of the projection area IA8 and the projected image (light irradiation area) of the micromirror arranged diagonally (at an angle θk) at the end of the -Y' direction of the projection area IA27 are set to overlap.

[0024] [Configuration of the Illumination Unit] Figure 4 is an optical layout diagram showing the specific configuration of module MU18 in exposure module MU(B) and module MU19 in exposure module MU(C) shown in Figures 1 and 2, viewed in the XZ plane. The Cartesian coordinate system XYZ in Figure 4 is set to be the same as the Cartesian coordinate system XYZ in Figures 1 to 3. As is clear from the arrangement of each module in the XY plane shown in Figure 2, module MU18 is shifted by a fixed distance in the +Y direction relative to module MU19, and they are installed back-to-back. Since the optical components in module MU18 and module MU19 are made of the same materials and configured identically, the optical configuration of module MU18 will be mainly described in detail here. Note that the optical fiber unit FBU shown in Figure 1 is composed of 27 optical fiber bundles FB1 to FB27, corresponding to the 27 modules MU1 to MU27 shown in Figure 2.

[0025] The illumination unit ILU of the module MU18 includes a mirror 100 that reflects illumination light ILm traveling in the −Z direction from the output end of the optical fiber bundle FB18, a mirror 102 that reflects the illumination light ILm from the mirror 100 in the −Z direction, an input lens system 104 that acts as a collimator lens, an illuminance adjustment filter 106, an optical integrator 108 that includes a micro fly's eye (MFE) lens, a field lens, etc., a condenser lens system 110, and an inclined mirror 112 that reflects the illumination light ILm from the condenser lens system 110 toward the DMD 10. The mirror 102, the input lens system 104, the optical integrator 108, the condenser lens system 110, and the inclined mirror 112 are arranged along an optical axis AXc that is parallel to the Z axis.

[0026] The optical fiber bundle FB18 is configured by a single optical fiber line or a bundle of multiple optical fiber lines. The illumination light ILm emitted from the output end of the optical fiber bundle FB18 (each of the optical fiber lines) has a numerical aperture (NA, also called a divergence angle) set so that it enters the downstream input lens system 104 without being eclipsed. Here, the illumination light ILm is light having a peak wavelength within a wavelength range of 10 nm or more and 410 nm or less, and the peak wavelength is, for example, any of 193 nm, 248 nm, 365 nm (i-line), 405 nm (h-line), and 436 nm (g-line).

[0027] The position of the front focal point of the input lens system 104 is designed to be the same as the position of the output end of the optical fiber bundle FB18. Furthermore, the position of the back focal point of the input lens system 104 is designed to superimpose illumination light ILm from a single or multiple point light sources formed at the output end of the optical fiber bundle FB18 on the incident surface side of the MFE lens 108A of the optical integrator 108. Therefore, the incident surface of the MFE lens 108A is Koehler illuminated by the illumination light ILm from the output end of the optical fiber bundle FB18. Note that in the initial state, the geometric center point of the output end of the optical fiber bundle FB18 in the XY plane is located on the optical axis AXc, and the chief ray (center line) of the illumination light ILm from the point light source at the output end of the optical fiber line is parallel to (or coaxial with) the optical axis AXc.

[0028] The illumination light ILm from the input lens system 104 is attenuated in illuminance by an illuminance adjustment filter 106 to a value between 0% and 90%, and then passes through an optical integrator 108 (including an MFE lens 108A, a variable aperture stop 108B, and a field lens) before entering a condenser lens system 110. The MFE lens 108A is a two-dimensional array of numerous rectangular microlenses, each measuring several tens of micrometers square. Its overall shape is set to be approximately similar to the overall shape of the mirror surface of the DMD 10 (with an aspect ratio of approximately 1:2) in the XY plane. The position of the front focal point of the condenser lens system 110 is set to be approximately the same as the position of the exit surface of the MFE lens 108A. A variable aperture stop (a sigma-value adjustable stop) 108B is provided on the exit surface side of the MFE lens 108A. Therefore, illumination light from point light sources formed on the exit side of each of the numerous microlenses of the MFE lens 108A that passes through the circular aperture of the variable aperture stop 108B is converted into a nearly parallel beam of light by the condenser lens system 110, reflected by the inclined mirror 112, and then superimposed on the DMD 10 to form a uniform illuminance distribution. Since a surface light source in which numerous point light sources (light-converging points) are densely arranged two-dimensionally is generated on the exit surface of the MFE lens 108A, the MFE lens 108A functions as a surface light source component. The variable aperture stop 108B also has the function of defining the shape of the surface light source formed on the exit surface.

[0029] 4 , optical axis AXc, which is parallel to the Z axis and passes through condenser lens system 110, is bent by inclined mirror 112 and reaches DMD 10, and the optical axis between inclined mirror 112 and DMD 10 is referred to as optical axis AXb. In this embodiment, a neutral plane including the center points of the numerous micromirrors of DMD 10 is set parallel to the XY plane. Therefore, the angle between the normal to that neutral plane (parallel to the Z axis) and optical axis AXb is the angle of incidence θα of illumination light ILm with respect to DMD 10.

[0030] The DMD 10 is attached to a fine movement stage 10S provided on a mount 10M fixed to a support column of the illumination unit ILU. The fine movement stage 10S can be, for example, a fine movement stage that combines a parallel link mechanism and an expandable piezoelectric element, as disclosed in International Patent Publication No. 2006 / 120927. This allows for fine adjustment of the position and attitude (angle) of the DMD 10.

[0031] [DMD Configuration] Next, the configuration of the DMD 10 will be described with reference to Figures 5(A) to 5(D). Figure 5(A) is a plan view showing the arrangement of multiple micromirrors Ms in the DMD 10 according to this embodiment, Figure 5(B) is a diagram showing the DMD 10 when the power is OFF, Figure 5(C) is a diagram for explaining the micromirrors in the ON state, and Figure 5(D) is a diagram for explaining the micromirrors in the OFF state. Note that in Figure 5(C), micromirrors in the ON state are indicated by hatching.

[0032] 5A, the DMD 10 has a plurality of micromirrors Ms whose tilt angles can be changed. In this embodiment, the DMD 10 is of a roll and pitch drive type, in which the on state and the off state are switched by tilting the micromirrors Ms in the roll direction and in the pitch direction.

[0033] The micromirrors Ms of the DMD 10 according to this embodiment have a substantially square outer shape and can rotate and tilt around axes parallel to the diagonals (around the X'-axis and the Y'-axis). The micromirrors Ms are also arranged rotated by a predetermined angle (for example, 45°) around an axis (the Z-axis) perpendicular to the plane on which the micromirrors Ms are arranged.

[0034] In the following description, the angle formed by the reflective surface of the micromirror Ms rotated around the Y' axis and the plane on which the micromirrors Ms are arranged (X'Y' plane) is referred to as the tilt angle of the micromirror Ms around the Y' axis, and is referred to as the θy' angle. Furthermore, the angle formed by the side of the micromirror Ms and the X' axis is referred to as the rotation angle around the Z axis, and is referred to as the θz angle. In the example of FIG. 5A, the θz angle is 45°. The θy' angle and the θz angle may be collectively referred to as the angle of the micromirror Ms.

[0035] 5B, when the power is OFF (the micromirrors Ms are in a neutral state), the reflective surface of each micromirror Ms is set parallel to the X'Y' plane. The arrangement pitch of each micromirror Ms in the X'-axis direction is Pdx (μm), and the arrangement pitch in the Y'-axis direction is Pdy (μm), but in practice, Pdx = Pdy.

[0036] Each micromirror Ms is turned on by tilting around the Y' axis. FIG. 5C shows a case where only the central micromirror Ms is turned on, while the other micromirrors Ms are in a neutral state (neither on nor off). Each micromirror Ms is turned off by tilting around the X' axis. FIG. 5D shows a case where only the central micromirror Ms is turned off, while the other micromirrors Ms are in a neutral state. For simplicity, although not shown, the micromirrors Ms in the on state are driven to tilt at a predetermined angle from the X'Y' plane so that illumination light irradiated onto the micromirrors Ms in the on state is reflected in the X-axis direction of the XZ plane. The micromirrors Ms in the off state are driven to tilt at a predetermined angle from the X'Y' plane so that illumination light irradiated onto the micromirrors Ms in the off state is reflected in the Y-axis direction of the YZ plane. The illumination light reflected by the micromirrors in the off state is absorbed by a light absorber (not shown).

[0037] The DMD 10 generates an exposure pattern by switching the on and off states of each micromirror Ms.

[0038] 4, illumination light ILm irradiated onto micromirrors Ms of the DMD 10 that are in the ON state is reflected in the X-axis direction within the XZ plane so as to head towards the projection unit PLU. On the other hand, illumination light ILm irradiated onto micromirrors Ms of the DMD 10 that are in the OFF state is reflected in the Y-axis direction within the YZ plane so as not to head towards the projection unit PLU.

[0039] As shown in FIG. 4 , a movable shutter 114 is removably provided in the optical path between the DMD 10 and the projection unit PLU to block light reflected from the DMD 10 during non-exposure periods. As shown on the module MU19 side, the movable shutter 114 is rotated to an angular position where it is removed from the optical path during exposure periods, and as shown on the module MU18 side, it is rotated to an angular position where it is inserted obliquely into the optical path during non-exposure periods. A reflective surface is formed on the DMD 10 side of the movable shutter 114, and light reflected therefrom from the DMD 10 is irradiated onto a light absorber 115. The light absorber 115 absorbs light energy in the ultraviolet wavelength range (wavelengths of 400 nm or less) without re-reflecting it and converts it into heat energy. For this reason, the light absorber 115 is also provided with a heat dissipation mechanism (heat dissipation fins and a cooling mechanism). Although not shown in Figure 4, the reflected light from the micromirror Ms of DMD 10, which is in the off state during the exposure period, is absorbed by a similar light absorber (not shown in Figure 4) installed in the Y-axis direction (a direction perpendicular to the plane of the paper in Figure 4) with respect to the optical path between DMD 10 and projection unit PLU, as described above.

[0040] [Configuration of Projection Unit] The projection unit PLU attached to the underside of the optical surface plate 5 is configured as a double-telecentric imaging projection lens system composed of a first lens system 116 and a second lens system 118 arranged along an optical axis AXa parallel to the Z axis. The first lens system 116 and the second lens system 118 are each configured to move translationally in the direction along the Z axis (optical axis AXa) by a micro-motion actuator relative to a support column fixed to the underside of the optical surface plate 5. The projection magnification Mp of the imaging projection lens system formed by the first lens system 116 and the second lens system 118 is determined by the relationship between the array pitches Pdx and Pdy of the micromirrors on the DMD 10 and the minimum line width (minimum pixel dimension) Pg of the pattern projected within the projection area IAn (n = 1 to 27) on the substrate P.

[0041] As an example, if the required minimum line width (minimum pixel dimension) Pg is 1 μm and the micromirror array pitches Pdx and Pdy are each 5.4 μm, the projection magnification Mp is set to approximately 1 / 6, taking into consideration the tilt angle θk in the XY plane of the projection area IAn (DMD 10) described above in Figure 3. The imaging projection lens system consisting of lens systems 116 and 118 inverts / reflects a reduced image of the entire mirror surface of DMD 10 and forms an image on the projection area IA18 (IAn) on the substrate P.

[0042] The first lens system 116 of the projection unit PLU is capable of slight movement in the direction of the optical axis AXa by an actuator in order to finely adjust the projection magnification Mp (on the order of ±several tens of ppm), and the second lens system 118 is capable of slight movement in the direction of the optical axis AXa by an actuator in order to perform high-speed focus adjustment. Furthermore, in order to measure positional changes in the Z-axis direction of the surface of the substrate P with an accuracy of submicron or less, a plurality of oblique incidence focus sensors 120 are provided below the optical surface plate 5. The plurality of focus sensors 120 measure overall positional changes in the Z-axis direction of the substrate P, positional changes in the Z-axis direction of partial areas on the substrate P corresponding to each of the projection areas IAn (n = 1 to 27), partial tilt changes of the substrate P, etc.

[0043] As explained above in Figure 3, the illumination unit ILU and projection unit PLU described above require that the projection area IAn be tilted by an angle θk in the XY plane, and therefore the DMD 10 and illumination unit ILU in Figure 4 (at least the optical path portion of mirrors 102 to 112 along the optical axis AXc) are arranged so that they are tilted overall by an angle θk in the XY plane.

[0044] [Imaging Light Path by DMD] Next, with reference to Figure 6, the imaging state of the micromirrors Ms of the DMD 10 by the projection unit PLU (imaging projection lens system) will be described in detail. The Cartesian coordinate system X'Y'Z in Figure 6 is the same as the coordinate system X'Y'Z shown in Figure 3, and Figure 6 illustrates the optical path from the condenser lens system 110 of the illumination unit ILU to the substrate P. Illumination light ILm from the condenser lens system 110 travels along the optical axis AXc, is totally reflected by the inclined mirror 112, and reaches the mirror surface of the DMD 10 along the optical axis AXb. Here, the micromirror Ms located at the center of the DMD 10 is referred to as Msc, and the micromirrors Ms located on the periphery are referred to as Msa, and these micromirrors Msc and Msa are assumed to be in the on state.

[0045] If the tilt angle of micromirror Ms in the on state is, for example, a standard value of 17.5° with respect to the X'Y' plane (XY plane), then the angle of incidence θα (the angle of optical axis AXb from optical axis AXa) of illumination light ILm irradiated onto DMD 10 is set to 35.0° in order to make the chief rays of reflected light Sc and Sa from micromirrors Msc and Msa parallel to the optical axis AXa of projection unit PLU. Accordingly, in this case, the reflective surface of tilted mirror 112 is also tilted by 17.5° (=θα / 2) with respect to the X'Y' plane (XY plane). The chief ray Lc of reflected light Sc from micromirror Msc is coaxial with the optical axis AXa, and the chief ray La of reflected light Sa from micromirror Msa is parallel to the optical axis AXa, so that the reflected light Sc and Sa enter projection unit PLU with a predetermined numerical aperture (NA).

[0046] The reflected light Sc forms a telecentric image ic of the micromirror Msc, which has been reduced by the projection magnification Mp of the projection unit PLU, on the substrate P at the position of the optical axis AXa. Similarly, the reflected light Sa forms a telecentric image ia of the micromirror Msa, which has been reduced by the projection magnification Mp of the projection unit PLU, on the substrate P at a position separated from the reduced image ic in the +X' direction. As an example, the first lens system 116 of the projection unit PLU is composed of two lens groups G1 and G2, and the second lens system 118 is composed of three lens groups G3, G4, and G5. An exit pupil (also simply referred to as a pupil) Ep is set between the lens group G3 and the lens group G4 of the second lens system 118. A light source image of the illumination light ILm (a collection of numerous point light sources formed on the exit surface side of the MFE lens 108A) is formed at the position of the pupil Ep, resulting in a Koehler illumination configuration. The pupil Ep is also called the aperture of the projection unit PLU, and the size (diameter) of this aperture is one factor that determines the resolving power of the projection unit PLU. In this embodiment, the pupil Ep is formed by a variable aperture stop 119 that includes an opening 119a that passes light from the DMD 10, and a light-shielding portion 119b that can block light from the DMD 10, as shown in the lower left of Figure 6.

[0047] The specularly reflected light from the micromirror Ms of the DMD 10 in the on state is set to pass through without being blocked by the maximum aperture (diameter) of the pupil Ep, and the numerical aperture NAi on the image side (substrate P side) in the equation R=k1·(λ / NAi), which expresses the resolution R, is determined by the maximum aperture of the pupil Ep and the distance of the rear (image side) focal point of the projection unit PLU (lens group G1 to G5 as an imaging projection lens system). Also, the numerical aperture NAo on the object plane (DMD 10) side of the projection unit PLU (lens group G1 to G5) is expressed as the product of the projection magnification Mp and the numerical aperture NAi, and when the projection magnification Mp is 1 / 6, then NAo=NAi / 6.

[0048] 4 and 6, the exit ends of the optical fiber bundles FBn (n = 1 to 27) connected to each module MUn (n = 1 to 27) are set by the input lens system 104 to be optically conjugate with the exit end side of the MFE lens 108A of the optical integrator 108, and the entrance end side of the MFE lens 108A is set by the condenser lens system 110 to be optically conjugate with the center of the mirror surface (neutral plane) of the DMD 10. As a result, the illumination light ILm irradiated onto the entire mirror surface of the DMD 10 has a uniform illuminance distribution (for example, intensity unevenness within ±1%) due to the action of the optical integrator 108. Furthermore, the exit end side of MFE lens 108A and the plane of pupil Ep of projection unit PLU are set in an optically conjugate relationship by condenser lens system 110 and lens groups G1 to G3 of projection unit PLU.

[0049] In projection exposure using the DMD 10, each of the numerous micromirrors Ms is rapidly switched between an on-state tilt and an off-state tilt based on pattern data (drawing data), and the substrate P is scanned and moved in the X direction at a speed corresponding to the switching speed to perform pattern exposure.

[0050] [Micromirror Tilt Angle and Optical Path Difference] Here, the angles of the micromirrors Ms may deviate from the standard value because there are variations in the angles of the micromirrors Ms due to individual differences in the DMD 10. If the angles of the micromirrors Ms deviate from the standard value, the optical path difference between the light beams incident on each micromirror Ms will change, which will affect the imaging performance of the pattern image generated by the DMD 10 on the substrate P.

[0051] 7 is a diagram illustrating the optical path difference in the DMD 10. In FIG. 7, micromirrors Ms1 to Ms3 that are adjacent in the X'-axis direction are in the ON state. If the pitch of the micromirrors in the ON state is Pdx, the optical path difference OPD1 between the light incident on micromirror Ms1 and the light incident on micromirror Ms2 is expressed as OPD1 = 2Pdx × sin φ cos φ, where φ is the tilt angle of micromirrors Ms1 to Ms3 around the Y'-axis.

[0052] Therefore, when φ changes, OPD1 also changes. Because the optical path difference changes depending on the angle of the micromirror Ms, it is important to accurately grasp the angle of the micromirror Ms in the ON state (the state of the micromirror Ms in the ON state). Therefore, in the first embodiment, the angle of the micromirror Ms in the ON state is measured (calculated) using a measuring device 500, which will be described later.

[0053] [Measurement Apparatus] A measurement apparatus 500 that measures the angle of the micromirror Ms included in the DMD 10 will be described. FIG. 8A is a diagram showing a schematic configuration of the measurement apparatus 500 according to the first embodiment. The measurement apparatus 500 directs measurement light to the DMD 10 on which the micromirror Ms is disposed in the ON state, and evaluates the ON state based on the relationship between the light (diffracted light) from the DMD 10 and a reference position, which will be described later. More specifically, the measurement apparatus 500 calculates the tilt angle (θy′ angle) and rotation angle (θz angle) of the micromirror in the ON state.

[0054] 8A, the measurement device 500 includes an attachment unit 501, a pattern control unit 502, a light source 503, an image capturing unit 504, a calculation unit 505, and a lens 506. If the σ of the light source 503 is small and the influence of the cover glass of the image capturing unit 504 is small, the lens 506 may be omitted as shown in FIG.

[0055] A chip CHP including a DMD 10 is attached to the attachment portion 501. A pattern control portion 502 controls the on and off states of each micromirror Ms provided on the DMD 10 to cause the DMD 10 to generate a pattern. A light source 503 irradiates measurement light onto the DMD 10. The light source 503 is, for example, a laser pointer.

[0056] The imaging unit 504 receives light (diffracted light) from the DMD 10. Specifically, when measurement light is irradiated onto the DMD 10, the imaging unit 504 images the intensity distribution of diffracted light due to the pattern generated by the DMD 10. Examples of the imaging unit 504 include a CMOS image sensor and a CCD image sensor. The imaging unit 504 is provided at the pupil position. Therefore, the imaging unit 504 images the intensity distribution in the pupil of diffracted light due to the pattern generated by the DMD 10.

[0057] The calculation unit 505 calculates the angle of the micromirror Ms included in the DMD 10 based on the image of the intensity distribution of diffracted light captured by the image capturing unit 504. Here, the principle of calculation of the angle of the micromirror Ms by the calculation unit 505 will be described.

[0058] 9 is a diagram showing an example of a pattern that the DMD 10 generates when measuring the angle of the micromirror Ms. In FIG. 9, region R1 indicates the region on the DMD 10 where the micromirrors Ms are arranged, and region R11 indicates the region irradiated with measurement light from the light source 503. Note that the light from the light source 503 may be irradiated over the entire region R1. When measuring the angle of the micromirror Ms, the pattern control unit 502 turns on at least some of the micromirrors Ms included in region R11, causing the DMD 10 to generate a pattern. In FIG. 9, the micromirrors Ms in the on state are indicated by hatching.

[0059] In FIG. 9 , the micromirrors Ms are turned on at regular intervals (Pon1x) in the X′-axis direction and at regular intervals (Pon1y) in the Y′-axis direction. Between the micromirrors Ms that are turned on in the X′-axis direction, two or more micromirrors Ms that are turned off are adjacent. Furthermore, between the micromirrors Ms that are turned on in the Y′-axis direction, two or more micromirrors Ms that are turned off are adjacent. The pattern shown in FIG. 9 can also be described as a pattern in which the micromirrors Ms that are turned on are arranged at a pitch Pon1, and the micromirrors Ms that are turned off are arranged at a pitch Poff1 that is smaller than the pitch Pon1. In the pattern shown in FIG. 9 , if one micromirror Ms is referred to as one pixel, the micromirrors Ms are turned on at intervals of five pixels in both the X′-axis direction and the Y′-axis direction, but this is not limited to this. The intervals between the micromirrors Ms that are turned on may be four pixels or less, or six pixels or more. It is also possible to turn on some of the micromirrors Ms included in the region R1 instead of the region R11, and generate the pattern shown in FIG. 9 over the entire region R1.

[0060] The light source 503 irradiates the region R11 with measurement light. When the measurement light irradiates the region R11, diffracted light is generated by the pattern formed in the region R11. The position at which the diffracted light occurs in the pupil depends on the distance between the micromirrors Ms in the on state and the wavelength of the light emitted by the light source 503.

[0061] FIG. 10 shows the results of a simulation of the intensity distribution of diffracted light obtained in the pupil when illumination light is irradiated onto region R11, on which the pattern shown in FIG. 9 is formed, when the tilt angle of the micromirror Ms is a standard value (e.g., 17.5°). In FIG. 10, small circles indicate positions in the pupil where diffracted light occurs, and the light intensity at the positions where the diffracted light occurs is indicated by the density of the hatching. The higher the hatching density, the higher the light intensity. Also in FIG. 10, point RP indicates the reference position, and point CP indicates the center position (vertex) of the intensity distribution. The center position CP of the intensity distribution is the peak position of the intensity distribution. Also, two dashed lines pass through the reference position RP and are parallel to the X'-axis direction and the Y'-axis direction, respectively. The same applies to other figures.

[0062] The reference position RP is used as a reference when calculating (measuring) the angle of the micromirror Ms in the ON state. Here, a method for setting the reference position RP will be described.

[0063] 11 is a diagram showing an example of a pattern that the pattern control unit 502 causes the DMD 10 to generate when setting the reference position RP. When setting the reference position RP, the pattern control unit 502 causes the DMD 10 to generate a pattern in which, for example, all of the micromirrors Ms included in at least region R11 are in the ON state. The pattern shown in FIG. 11 can also be said to be a pattern in which the ON-state micromirrors Ms are arranged at a pitch Pon2 that is smaller than the pitch Pon1 of the ON-state micromirrors Ms shown in FIG. 9. Note that the pattern control unit 502 may also cause the DMD 10 to generate a pattern in which all of the micromirrors Ms included in region R1 are in the ON state.

[0064] Fig. 12 shows the results of a simulation of the intensity distribution in the pupil of diffracted light generated when measurement light is irradiated onto region R11 in which the pattern shown in Fig. 11 is generated. Diffracted light beams DL1 to DL5 can be observed as shown in Fig. 12. In the pattern shown in Fig. 11, the spacing between the on-state micromirrors Ms is smaller than in the pattern shown in Fig. 9, and therefore the number of diffracted light beams generated is smaller than the number of diffracted light beams generated by the pattern shown in Fig. 9. In other words, the diffracted light beams generated by the pattern shown in Fig. 11 are distributed at intervals DST2, which are larger than the intervals DST1 (see Fig. 10) at which the diffracted light beams generated by the pattern shown in Fig. 9 are distributed.

[0065] In this embodiment, the calculation unit 505 sets the position (peak position) of the diffracted light DL1 with the highest intensity among the diffracted lights generated by the pattern shown in Fig. 11 as the reference position RP. The reason for setting the reference position RP based on the diffracted light generated by the pattern shown in Fig. 11 is to eliminate the influence of the assembly state of the chip CHP including the DMD 10 to the mounting unit 501, etc.

[0066] In this embodiment, the calculation unit 602 calculates the angle of the micromirror Ms in the ON state in the region R11 irradiated with the measurement light based on the positional relationship between the reference position RP and the center position CP of the intensity distribution of the diffracted light (evaluates the state of the micromirror Ms in the ON state). Here, the intensity distribution of the diffracted light obtained when the angle of the micromirror Ms in the ON state deviates from the standard value (when a driving error occurs) will be described.

[0067] FIG. 13 shows the simulation results of the intensity distribution of diffracted light obtained when measurement light is irradiated onto region R11, on which the pattern shown in FIG. 9 is formed, in a case where the θy′ angle (tilt angle around the Y′ axis) of the micromirror Ms in the on-state is deviated by +0.5° from the standard value. It is assumed that the θz angle (rotation angle around the Z axis) of the micromirror Ms in the on-state is the standard value. As described above, the position where diffracted light occurs in the pupil depends on the pitch Pon1 of the micromirrors Ms in the on-state and the wavelength of the light emitted by the light source 503. Therefore, the position of the diffracted light shown in FIG. 13 is the same as the position of the diffracted light shown in FIG. 10. However, because the θy′ angle of the micromirror Ms in the on-state is deviated by +0.5° from the standard value, the intensity distribution is shifted in the direction indicated by the arrow from the intensity distribution shown in FIG. 10.

[0068] FIG. 14 shows the simulation results of the intensity distribution in the pupil of diffracted light obtained when measurement light is irradiated onto region R11, on which the pattern shown in FIG. 9 is formed, in a case where the θy′ angle of the micromirror Ms in the on-state is deviated by −0.5° from the standard value. It is assumed that the θz angle of the micromirror Ms in the on-state is the standard value. As described above, the position where diffracted light occurs in the pupil depends on the pitch Pon1 of the micromirrors Ms in the on-state and the wavelength of the measurement light emitted by the light source 503. Therefore, the position of the diffracted light shown in FIG. 14 is the same as the position of the diffracted light shown in FIG. 10. However, because the θy′ angle of the micromirror Ms in the on-state is deviated by −0.5° from the standard value, the intensity distribution is shifted in the direction indicated by the arrow from the intensity distribution shown in FIG. 10.

[0069] FIG. 15 shows the simulation results of the intensity distribution in the pupil of diffracted light obtained when measurement light is irradiated onto region R11, on which the pattern shown in FIG. 9 is formed, when the θz angle of the micromirror Ms in the on-state is deviated by +2° from the standard value. Note that the θy′ angle of the micromirror Ms in the on-state is assumed to be the standard value. As described above, the position where diffracted light occurs in the pupil depends on the pitch Pon1 of the micromirrors Ms in the on-state and the wavelength of the measurement light emitted by the light source 503. Therefore, the position of the diffracted light shown in FIG. 15 is the same as the position of the diffracted light shown in FIG. 10. However, because the θz angle of the micromirror Ms in the on-state is deviated by +2° from the standard value, the intensity distribution shifts in the direction indicated by the arrow from the intensity distribution shown in FIG. 10.

[0070] FIG. 16 shows the simulation results of the intensity distribution in the pupil of diffracted light obtained when measurement light is irradiated onto region R11, on which the pattern shown in FIG. 9 is formed, in a case where the θz angle of the micromirror Ms in the on-state is deviated by −2° from the standard value. It is assumed that the θy′ angle of the micromirror Ms in the on-state is the standard value. As described above, the position where diffracted light occurs in the pupil depends on the pitch Pon1 of the micromirrors Ms in the on-state and the wavelength of the measurement light emitted by the light source 503. Therefore, the position of the diffracted light shown in FIG. 16 is the same as the position of the diffracted light shown in FIG. 10. However, because the θz angle of the micromirror Ms in the on-state is deviated by −2° from the standard value, the intensity distribution shifts in the direction indicated by the arrow from the intensity distribution shown in FIG. 10.

[0071] In this way, deviations of the θy′ angle and the θz angle from their standard values ​​change the center position CP of the intensity distribution of the diffracted light in the pupil. That is, deviations of the θy′ angle from its standard value (referred to as driving error Δθy′) and deviations of the θz angle from its standard value (referred to as driving error Δθz) change the positional relationship between the center position CP of the intensity distribution and the reference position RP.

[0072] Therefore, specifically, the calculation unit 505 calculates the angle (θy' angle, θz angle) of the micromirror Ms in the on state using an image of the intensity distribution of the diffracted light from the DMD 10 in which the on-state micromirrors Ms are arranged at a pitch Pon1 and an image of the diffracted light from the DMD 10 in which the on-state micromirrors Ms are arranged at a pitch Pon2 which is smaller than the pitch Pon1.

[0073] More specifically, the calculation unit 505 obtains the center position CP of the intensity distribution from an image of the intensity distribution of the diffracted light from the DMD 10 in which the on-state micromirrors Ms are arranged at a pitch Pon1, obtains the reference position RP from the peak position of the diffracted light from the DMD 10 in which the on-state micromirrors Ms are arranged at a pitch Pon2 which is smaller than the pitch Pon1, and obtains the relationship between the center position CP of the intensity distribution and the reference position RP.

[0074] The calculation unit 505 then calculates the angles (θy' angle, θz angle) of the micromirror Ms by applying the acquired relationship between the reference position RP and the center position CP of the intensity distribution to a map that indicates the relationship between the reference position RP and the center position of the intensity distribution for combinations of the drive errors Δθy' and Δθz, which map has been created in advance by simulation, etc. Note that the calculation unit 505 may calculate the angles (θy' angle, θz angle) of the micromirror Ms by using the drive errors Δθy', Δθz, and equations that indicate the relationship between the reference position RP and the center position CP of the intensity distribution, which have been derived by simulation, etc.

[0075] Based on the angles (θy' angle, θz angle) of the micromirror Ms calculated in this manner, the exposure apparatus EX (optical apparatus) performs at least one of the following adjustments: (1) adjusting the position or angle of at least one optical member in the illumination unit ILU; (2) adjusting the position or angle of at least one optical member in the projection unit PLU; (3) adjusting the installation state of the DMD 10; and (4) adjusting the tilt angle (θy' angle) of the micromirror Ms in the ON state. The tilt angle (θy' angle) of the micromirror Ms can be adjusted by adjusting the voltage applied to the micromirror Ms. For example, if the θy' angle of the micromirror Ms deviates from the standard value, the actual θy' angle of the micromirror Ms can be adjusted by adjusting the voltage applied to the micromirror Ms. Furthermore, if the θz angle of the micromirror Ms deviates from the standard value, the drive error Δθz can be corrected by adjusting the tilt angle of, for example, the tilt mirror 112 of the illumination unit ILU to adjust the angle of incidence of the illumination light on the DMD 10. This makes it possible to improve the imaging performance of the image formed by the pattern generated by the DMD 10 in the exposure apparatus EX.

[0076] As described above in detail, according to the first embodiment, the measurement device 500 directs measurement light toward the DMD 10 on which multiple tiltable micromirrors Ms are arranged, receives diffracted light from the DMD 10 with the imaging unit 504, and evaluates the on-state of the micromirrors Ms based on the relationship between the received diffracted light and the reference position RP. Specifically, the measurement device 500 evaluates the on-state of the micromirrors Ms based on the intensity distribution of the diffracted light and the reference position RP. By using the intensity distribution of the diffracted light and the reference position RP, the θy' angle and θz angle of the micromirror Ms in the on-state can be determined, and the state of the micromirror Ms in the on-state can be determined with high accuracy.

[0077] Furthermore, according to the first embodiment, the measurement device 500 generates a pattern by turning on at least some of the micromirrors M included in region R11, among the region R11 in which the multiple micromirrors Ms provided in the DMD 10 are arranged, irradiates region R11 with measurement light, obtains the intensity distribution in the pupil of the diffracted light due to the pattern when region R11 is irradiated with the measurement light, and calculates the angle of the mirror in the on state based on the intensity distribution. This makes it possible to calculate the θy' angle and θz angle of the mirror in the on state with high accuracy.

[0078] (Variation 1) In the first embodiment, the peak position of the diffracted light generated when, for example, all of the micromirrors Ms included in the region R11 are turned on is determined as the reference position RP, but this is not limited to this. Fig. 17 is a diagram showing an example of an image of the intensity distribution in the pupil of the diffracted light due to the pattern generated by the DMD 10.

[0079] 17 shows the intensity distribution of diffracted light DLon generated by the micromirror Ms in the ON state, as well as diffracted light DLoff1 to DLoff7 generated by the micromirror Ms in the OFF state. That is, diffracted light DLoff1 to DLoff7 are diffracted light from region R11 that includes a micromirror Ms (a micromirror in the OFF state) tilted at an angle different from the tilt angle of the micromirror Ms in the ON state.

[0080] If such an image can be acquired, the diffracted light beams DLoff1 to DLoff7 may be used as reference positions, and the angle of the micromirror Ms may be calculated based on the relationship between these reference positions and the center position CP of the intensity distribution. In this case, it is not necessary to generate a pattern in which all of the micromirrors Ms included in region R11 are in the on state to determine the reference position RP, thereby reducing the time required to calculate the tilt angle of the micromirror Ms.

[0081] (Variant 2) In the first embodiment described above, in order to obtain the intensity distribution of diffracted light in the pupil, a pattern was generated in which micromirrors Ms were turned on at a predetermined interval in the X'-axis direction and at a predetermined interval in the Y'-axis direction in at least region R11 of DMD 10, but this is not limited to this.

[0082] 18A and 18B are diagrams showing another example of a pattern generated by the DMD 10 when measuring the tilt angle of the micromirror Ms in the ON state. In Modification 2, two patterns are generated by the DMD 10, and the center of the intensity distribution is found from the intensity distribution of the diffracted light by each pattern.

[0083] First, the pattern control unit 502 causes the DMD 10 to generate a pattern in which adjacent micromirrors Ms in the Y'-axis direction are turned on at a predetermined pitch in the X'-axis direction, at least in region R11, as shown in Fig. 18(A). Also, the pattern control unit 502 causes the DMD 10 to generate a pattern in which adjacent micromirrors Ms in the X'-axis direction are turned on at a predetermined pitch in the Y'-axis direction, at least in region R11, as shown in Fig. 18(B).

[0084] 19 and 20 show simulation results of the intensity distribution in the pupil of the diffracted light DLon generated by the patterns shown in FIGS. 18(A) and 18(B), respectively.

[0085] The calculation unit 505 acquires the center position of the intensity distribution by combining the image of the intensity distribution shown in Fig. 19 with the image of the intensity distribution shown in Fig. 20. Specifically, the calculation unit 505 acquires the center position of the intensity distribution in the X'-axis direction from the intensity distribution shown in Fig. 19, and acquires the center position of the intensity distribution in the Y'-axis direction from the intensity distribution shown in Fig. 20. This allows the calculation unit 505 to calculate the tilt angle (θy' angle, θz angle) of the micromirror Ms in the on-state from the positional relationship between the reference position RP and the center position of the intensity distribution.

[0086] In the first embodiment and its modifications, it is preferable to change the illumination NA of the measurement light illuminating the DMD 10, obtain the intensity distribution of the diffracted light under each condition, and calculate the angle of the micromirror Ms. That is, it is preferable to obtain the intensity distribution of the diffracted light under each of two or more conditions with different illumination NAs and calculate the angle of the micromirror Ms in the on state. This improves the accuracy of calculating the angle of the micromirror Ms in the on state.

[0087] Furthermore, in the first embodiment and its modified examples, it is preferable to change the wavelength condition of the measurement light illuminating the DMD 10, obtain the intensity distribution of the diffracted light under each condition, and calculate the tilt angle of the micromirror Ms. That is, it is preferable to obtain the intensity distribution of the diffracted light for each of two or more conditions under which the wavelength of the measurement light illuminating the DMD 10 is different, and calculate the angle of the micromirror Ms in the on state. In this case, the light source 503 may emit a plurality of measurement light beams having different wavelengths as measurement light onto the DMD 10, or the measurement device 500 may include a plurality of light sources 503 that each emit a plurality of measurement light beams having different wavelengths as measurement light onto the DMD 10. This improves the accuracy of calculating the angle of the micromirror Ms in the on state.

[0088] Furthermore, in the first embodiment and its modifications, it is preferable to generate multiple patterns on the DMD 10, obtain the intensity distribution of diffracted light for each pattern, and calculate the angle of the micromirror Ms in the on-state. That is, it is preferable to obtain the intensity distribution of diffracted light for each of two or more conditions in which the DMD 10 generates patterns with different characteristics, and calculate the angle of the micromirror Ms in the on-state. This improves the accuracy of calculating the angle of the micromirror Ms in the on-state. For example, by calculating the angle of the micromirror Ms in the on-state based on the intensity distribution of diffracted light for the pattern described in the first embodiment and the intensity distribution of diffracted light for the pattern described in Modification 2, it is possible to improve the accuracy of calculating the angle of the micromirror Ms in the on-state.

[0089] Second Embodiment In the first embodiment described above, the measurement device 500 was used to measure the tilt angles (θy′ angle, θz angle) of the micromirrors Ms provided in the DMD 10, but it is also possible to measure the angles (θy′ angle, θz angle) of the micromirrors Ms in the on state in the exposure apparatus EX.

[0090] FIG. 21 is a diagram that shows roughly the configuration for measuring the angle of the micromirror Ms in the ON state in the exposure apparatus EX.

[0091] In the exposure apparatus EX, the above-described illumination unit ILU irradiates light onto the DMD 10. In the second embodiment, the light irradiated onto the DMD 10 in order to measure the angle of the micromirror Ms in the on state is referred to as measurement light, and the light irradiated onto the DMD 10 in order to form the pattern generated by the DMD 10 on the substrate P by exposure is referred to as illumination light.

[0092] An image of the intensity distribution of diffracted light caused by the pattern generated by the DMD 10 is acquired by an optical measurement unit OMU (acquisition unit) provided in a calibration reference unit CU attached to the end of the substrate holder 4B of the exposure apparatus EX.

[0093] Fig. 22 is a diagram showing a schematic configuration of the optical measurement unit OMU provided in the calibration reference unit CU attached to the end portion on the substrate holder 4B of the exposure apparatus EX shown in Fig. 1. In Fig. 22, it is assumed that the reflected light Sa from the DMD 10 passes through the lens groups G4 and G5 on the image plane side of the projection unit PLU, and is imaged on the best focus plane (best image formation plane) IPo, and that the chief ray La of the reflected light Sa is parallel to the optical axis AXa.

[0094] The optical measurement unit OMU includes a pinhole plate 340 attached to the upper surface of the calibration reference unit CU, an objective lens 342 that forms an image of the pupil Ep of the projection unit PLU (the intensity distribution of the diffracted light within the pupil Ep) by receiving reflected light (diffracted light) Sa from the DMD 10 projected from the projection unit PLU via the pinhole plate 340, and an image sensor 344 by CCDD or CMOS that captures the image of the pupil Ep. In other words, the imaging surface of the image sensor 344 of the optical measurement unit OMU is conjugate with the position of the pupil Ep of the projection unit PLU.

[0095] 21, the exposure apparatus EX has a control unit CNT that controls each component of the exposure apparatus EX. The control unit CNT includes a pattern control unit 601, a calculation unit 602, a drive control unit 603, and the like.

[0096] The pattern control unit 601 controls the on and off states of the micromirrors Ms included in the DMD 10 to generate a pattern based on pattern data (drawing data) on the DMD 10. The calculation unit 602 calculates the angle of the micromirrors Ms in the on state based on an image of the intensity distribution of diffracted light captured by the image sensor 344 included in the optical measurement unit OMU.

[0097] The drive control unit 603 controls each unit of the exposure apparatus EX based on the angle of the micromirror Ms calculated by the calculation unit 602 or the intensity distribution of the diffracted light captured by the image capture element 344. Specifically, the drive control unit 603 performs at least one of the following: (1) adjusting the position or angle of at least one optical member in the illumination unit ILU, (2) adjusting the position or angle of at least one optical member in the projection unit PLU, (3) adjusting the position or angle of the DMD 10, and (4) adjusting the tilt angle (θy′ angle) of the micromirror Ms in the on state.

[0098] Furthermore, when measuring the angle of the micromirror Ms in the ON state, the drive control unit 603 performs at least one of (1) adjusting the position or angle of at least one optical member in the illumination unit ILU, and (2) adjusting the position or angle of at least one optical member in the projection unit PLU. Specifically, by adjusting the variable aperture stop 108B provided in the illumination unit ILU, the size of the surface light source when measuring the angle of the micromirror Ms in the ON state is made smaller than the size of the surface light source when forming a pattern on the substrate P by exposure.

[0099] 23A is a diagram showing an example of a pattern that the pattern control unit 601 causes the DMD 10 to generate when measuring the angles of the micromirrors Ms in the ON state in the second embodiment. As shown in FIG. 23A, the pattern control unit 601 turns on all of the micromirrors Ms included in at least the region where the micromirrors Ms are arranged and that is irradiated with measurement light from the illumination unit ILU. The pattern control unit 601 may also turn on all of the micromirrors Ms included in the DMD 10.

[0100] Figures 23(B) to 23(D) show simulation results of the intensity distribution of diffracted light generated by the pattern shown in Figure 23(A). Figure 23(B) shows the simulation result when the θy' angle of the micromirror Ms is 11.6° and the incident angle of the illumination light from the illumination unit ILU to the DMD 10 is 23.2°, Figure 23(C) shows the simulation result when the θy' angle is 12° and the incident angle of the illumination light is 24°, and Figure 23(D) shows the simulation result when the θy' angle is 12.4° and the incident angle of the illumination light is 24.8°.

[0101] In this embodiment, the illumination NA of the measurement light emitted from the illumination unit ILU is set to a value larger than the illumination NA of the measurement light used in the first embodiment, so unlike the first embodiment, the diffracted light does not separate. Also, because the pitch between the micromirrors Ms in the on state is short, the period of the diffracted light becomes coarse. As a result, for example, four diffracted light beams DL1 to DL4 are generated at the position of the pupil Ep, as shown in Figures 23(B) to 23(D).

[0102] Next, a method for calculating the center position of the intensity distribution of diffracted light, which is executed by the calculation unit 602 in the second embodiment, will be described with reference to FIGS.

[0103] 24A shows the simulation results of the intensity distribution of diffracted light generated by the pattern shown in FIG. 23A when the θy′ angle of the micromirror Ms is 11.6° and the angle of incidence of illumination light from the illumination unit ILU to the DMD 10 is 23.2°. In reality, the diffracted light DL1 to DL4 is partially blocked by the light-shielding portion 119b of the variable aperture stop 119 that defines the pupil Ep, so the image sensor 344 obtains an image with the intensity distribution shown in FIG. 24B. Therefore, only the shape of the illumination NA is visible in the actual image. Because the shape of the illumination NA is diffracted into four circles (diffracted light), the calculation unit 602 fits the outer edges of the luminous fluxes of the diffracted light DL1 to DL4 based on the shape of the illumination NA.

[0104] Next, the calculation unit 602 determines the center positions DP1 to DP4 of the diffracted light at the position of the pupil Ep from the fitting results of each of the diffracted light DL1 to DL4 (see FIG. 24A).

[0105] Fig. 24(C) is a graph schematically showing the theoretical point spread function Iea of ​​the light beam (here, zeroth-order diffracted light) Is at the pupil Ep due to reflected light Sa from a single row (or a single unit) of micromirrors Ms isolated in the X'-axis direction when there is no drive error Δθy'. In the graph of Fig. 24(C), the horizontal axis represents the coordinate position in the X' (or Y') direction, with the position of the optical axis of the zeroth-order diffracted light as the origin, and the vertical axis represents the light intensity Ie. In Fig. 24(C), Io represents the peak value of the light intensity Ie, and the position of the peak value Io of reflected light Sa from a single row (or a single unit) of micromirrors Msa coincides with the origin 0 in the X' (or Y') direction, i.e., the position of the optical axis of the zeroth-order diffracted light.

[0106] If the tilt angle of the micromirror Ms has a drive error Δθy', the center position of the point spread function Iea will be shifted by ΔDx in the X'-axis direction from the position of the optical axis of the zeroth-order diffracted light, as shown in Figure 25(A). The shift amount ΔDx corresponds to the magnitude of the drive error Δθy' of the micromirror Ms in the ON state.

[0107] Therefore, the calculation unit 602 calculates the angle of the micromirror Ms by utilizing the above-mentioned property. First, the calculation unit 602 obtains the light intensity at the center positions DP1 to DP4 of the diffracted light from the intensity distribution image. For example, as shown in FIG. 25B, the calculation unit 602 obtains the light intensity I_DP1 at the center position DP1 and the light intensity I_DP3 at the center position DP3.

[0108] Here, for example, the distance between the center position DP1 and the center position DP3 of the diffracted light corresponds to the angular difference between the diffraction angle of the diffracted light DL1 and the diffraction angle of the diffracted light DL3. That is, the X' coordinate in Figure 25(A) corresponds to the angle of the diffracted light.

[0109] The calculation unit 602 acquires the position of the peak value Io in the point spread function by applying an equation representing the point spread function of the diffracted light to FIG. 25B based on the angular difference between the diffraction angle of the diffracted light DL1 and the diffraction angle of the diffracted light DL3, the light intensity I_DP1 of the diffracted light DL1, and the light intensity I_DP3 of the diffracted light DL3, as shown by the dotted line in FIG. 25C. In other words, the calculation unit 602 calculates the peak of the intensity distribution of the diffracted light generated by the pattern shown in FIG. 23A in accordance with the angular difference calculated from the diffraction angles of at least two diffracted lights generated by the pattern shown in FIG. 23A and the light intensities of the at least two diffracted lights. Note that the angular difference calculated from the diffraction angles of at least two diffracted lights is obtained by fitting the shape of the illumination NA to the outer edge (shape) of the diffracted light and determining the center of the diffracted light from the fitting result. Therefore, it can also be said that the angular difference is calculated based on the shape of the illumination NA illuminating the DMD 10. In the example of FIG. 25C, the diffracted light DL1 is 0th-order diffracted light and the diffracted light DL3 is +1st-order diffracted light, but the orders of the diffracted light DL1 and the diffracted light DL3 are not limited to this.

[0110] Next, the calculation unit 602 calculates the amount of deviation ΔDx between the position where the peak value Io exists in the point spread function and the center position DP1 (the position of the zeroth-order diffracted light). Similarly, the calculation unit 602 calculates the amount of deviation ΔDy between the position where the peak value exists in the Y'-axis direction and the position of the zeroth-order diffracted light. Because ΔDx and ΔDy are values ​​that correspond to the drive errors Δθy' and Δθz of the tilt angle of the micromirror Ms, the calculation unit 602 can calculate the angle of the micromirror Ms in the on-state from the amount of deviation ΔDx.

[0111] For example, if the θy' angle of the micromirror Ms deviates from a standard value, the drive control unit 603 can adjust the θy' angle of the micromirror Ms in the on state by adjusting the voltage applied to the micromirror Ms, thereby correcting the drive error Δθy'. Also, if the θz angle of the micromirror Ms deviates from a standard value, the drive control unit 603 can correct the drive error Δθz by adjusting the tilt angle of, for example, the tilt mirror 112 of the illumination unit ILU, thereby adjusting the angle of incidence of the illumination light to the DMD 10.

[0112] As described above in detail, according to the second embodiment, the exposure apparatus EX includes a DMD 10 including a plurality of tiltable micromirrors Ms arranged two-dimensionally, an illumination unit ILU that irradiates illumination light onto the DMD 10, a projection unit PLU that irradiates a substrate with light from the DMD 10, an optical measurement unit OMU that acquires the intensity distribution of diffracted light from the DMD 10, and a control device CNT. Based on the intensity distribution of the diffracted light, the control device CNT (drive control unit 603) adjusts the position or angle of at least one optical member within the illumination unit ILU or projection unit PLU, adjusts the position or angle of the DMD 10, and adjusts the tilt angle of the micromirrors Ms in the on state. This makes it possible to improve the imaging performance of the image of the pattern generated by the DMD 10 onto the substrate P when the pattern is formed on the substrate P by exposure.

[0113] In the second embodiment, it is preferable to change the illumination NA of the measurement light illuminating the DMD 10, obtain the intensity distribution of the diffracted light under each condition, and calculate the tilt angle of the micromirror Ms. That is, it is preferable to obtain the intensity distribution of the diffracted light under each of two or more conditions with different illumination NAs and calculate the angle of the micromirror Ms in the on state. This improves the accuracy of calculating the angle of the micromirror Ms in the on state. The same applies to the modified examples described below.

[0114] Furthermore, in the second embodiment, it is preferable to change the condition of the wavelength of the measurement light illuminating the DMD 10, obtain the intensity distribution of the diffracted light under each condition, and calculate the angle of the micromirror Ms in the ON state. That is, it is preferable to obtain the intensity distribution of the diffracted light under each of two or more conditions with different wavelengths of the measurement light, and calculate the angle of the micromirror Ms in the ON state. This improves the accuracy of calculating the angle of the micromirror Ms in the ON state. The same applies to the modified examples described below.

[0115] In the second embodiment, the illumination NA of the measurement light may be reduced by the variable aperture stop 108B provided in the illumination unit ILU, so that the tilt angle of the micromirror Ms in the ON state can be calculated using the method described in the first embodiment and its modifications. In this case, the outer edge of the pupil Ep can be used as the reference position. The outer edge of the pupil Ep is the boundary position between the opening 119a and the light-shielding portion 119b of the variable aperture stop 119 that defines the pupil Ep. For example, the center of the pupil Ep may also be used as the reference position. The reference position may also be the peak position of the diffracted light used in the first embodiment and its modifications (see FIG. 12). At this time, the drive control unit 603 may perform at least one of the following adjustments so that the center position of the intensity distribution approaches the center of the pupil Ep or the peak position of the diffracted light: (1) adjusting the position or angle of at least one optical element in the illumination unit ILU; (2) adjusting the position or angle of at least one optical element in the projection unit PLU; (3) adjusting the position and angle of the DMD 10; or (4) adjusting the tilt angle (θy' angle) of the micromirror Ms in the on state.

[0116] Furthermore, in the second embodiment, the drive control unit 603 may adjust the position or angle of at least one optical member in the illumination unit ILU or the projection unit PLU, adjust the position or angle of the DMD 10, and adjust the tilt angle of the micromirror Ms in the on state based on the position where the peak value Io exists in the point spread function, instead of the angle of the micromirror Ms calculated by the calculation unit 602. For example, the drive control unit 603 may perform at least one of the above adjustments so that the position where the peak value Io exists in the point spread function coincides with the position of the zeroth-order diffracted light.

[0117] (Variation 1) In the second embodiment described above, a pattern was generated in which all of the micromirrors Ms included in the area irradiated with measurement light from the illumination unit ILU were in the ON state. However, this is not limited to this. Figures 26A and 26B are diagrams showing another example of a pattern that the pattern control unit 601 causes the DMD 10 to generate. As shown in Figure 26A, the pattern control unit 601 causes the DMD 10 to generate a pattern in which adjacent micromirrors Ms in the Y'-axis direction are in the ON state at a predetermined interval in the X'-axis direction. Furthermore, as shown in Figure 26B, the pattern control unit 601 causes the DMD 10 to generate a pattern in which adjacent micromirrors Ms in the X'-axis direction are in the ON state at a predetermined interval in the Y'-axis direction.

[0118] Figures 27(A) to 27(C) show simulation results of the intensity distribution in the pupil of diffracted light produced by the pattern shown in Figure 26(A). Figure 27(A) shows the simulation result when the θy' angle of the micromirror Ms deviates from the standard value by -0.4°, Figure 27(B) shows the simulation result when the θy' angle of the micromirror Ms is the standard value, and Figure 27(C) shows the simulation result when the θy' angle of the micromirror Ms deviates from the standard value by +0.4°. Note that the θz angle of the micromirror Ms is the standard value. The illumination NA of the measurement light is set larger than the illumination NA of the measurement light in the first embodiment.

[0119] 27B, when the θy′ angle of the micromirror Ms is a standard value, the intensity distribution of the diffracted light is symmetrical about the center of the pupil Ep in the X′-axis direction. That is, in FIG. 27B, the intensity distribution on the left side and the intensity distribution on the right side of the pupil Ep are approximately equal.

[0120] On the other hand, as shown in Figures 27(A) and 27(C), when the θy' angle of the micromirror Ms deviates from the standard value, the intensity distribution of the diffracted light in the X'-axis direction becomes asymmetric, and it can be seen that the degree (tendency) of asymmetry changes depending on the amount of deviation from the standard value.

[0121] 28(A) to 28(C) show simulation results of the intensity distribution of diffracted light generated by the pattern shown in FIG. 26(B). FIG. 28(A) shows the simulation results when the θy′ angle of the micromirror Ms deviates from the standard value by −0.4°, FIG. 28(B) shows the simulation results when the θy′ angle of the micromirror Ms is the standard value, and FIG. 28(C) shows the simulation results when the θy′ angle of the micromirror Ms deviates from the standard value by +0.4°. Note that the θz angle of the micromirror Ms is the standard value. The illumination NA of the measurement light is set larger than the illumination NA of the measurement light in the first embodiment.

[0122] 28B, when the θy′ angle of the micromirror Ms is a standard value, the intensity distribution of the diffracted light is symmetrical about the center of the pupil Ep in the Y′-axis direction. That is, in FIG. 28B, the intensity distribution on the upper side and the intensity distribution on the lower side within the pupil Ep are approximately equal.

[0123] On the other hand, as shown in Figures 28(A) and 28(C), when the θy' angle of the micromirror Ms deviates from the standard value, the intensity distribution of the diffracted light in the Y'-axis direction becomes asymmetric, and it can be seen that the degree (tendency) of asymmetry changes depending on the amount of deviation from the standard value.

[0124] 29 is a graph showing the intensity ratio in the X'-axis direction within the pupil Ep (intensity on the right side of the pupil Ep / intensity on the left side of the pupil Ep) and the intensity ratio in the Y'-axis direction within the pupil Ep (intensity on the upper side of the pupil Ep / intensity on the lower side of the pupil Ep) when the θy' angle of the micromirror Ms is the standard value of -0.6°, the standard value, and the standard value of +0.6°. As shown in FIG. 29, when the θy' angle of the micromirror Ms is the standard value, the intensity ratio is approximately 1, but it can be seen that the intensity ratio changes depending on the amount and direction of deviation from the standard value. Asymmetry also appears in the intensity distribution when the θz angle deviates from the standard value.

[0125] Therefore, the calculation unit 602 can calculate the peak of the virtual light intensity distribution based on the degree (tendency) of asymmetry, i.e., the intensity ratio of the diffracted light, and can calculate the angle of the micromirror Ms from the positional relationship between the position of the peak of the virtual light intensity distribution and the reference position, for example, using the center of the pupil Ep as the reference position.

[0126] In Modification 1, the drive control unit 603 may perform at least one of the following adjustments: (1) adjusting the position or angle of at least one optical member in the illumination unit ILU, (2) adjusting the position or angle of at least one optical member in the projection unit PLU, and (3) adjusting the angle of the micromirror Ms in the ON state, so that the intensity distribution of the diffracted light in the X'-axis direction and the intensity distribution of the diffracted light in the Y'-axis direction are symmetrical, rather than based on the calculated angle of the micromirror Ms. Alternatively, the drive control unit 603 may perform at least one of the following adjustments: (1) adjusting the position or angle of at least one optical member in the illumination unit ILU, (2) adjusting the position or angle of at least one optical member in the projection unit PLU, and (3) adjusting the angle of the micromirror Ms in the ON state, so that the peak of the calculated virtual light intensity distribution coincides with, for example, the center of the pupil Ep.

[0127] Furthermore, in the second embodiment and its modified example, the measurement light emitted by the illumination unit ILU is irradiated onto the DMD 10 to measure the angle of the micromirror Ms in the on state, but a light source that emits measurement light may be provided separately from the illumination unit ILU.

[0128] 30A and 30B are diagrams showing another example of the configuration for measuring the angle of the micromirror Ms in the ON state in the exposure apparatus EX.

[0129] As shown in Fig. 30A, a light source LS1 separate from the illumination unit ILU may be provided, and the angle of the micromirror Ms in the ON state may be measured by irradiating the DMD 10 with measurement light emitted from the light source LS1. Also, in Fig. 30A, measurement light is irradiated onto the DMD 10 from the same direction as the illumination unit ILU, but as shown in Fig. 30B, measurement light may be irradiated onto the DMD 10 from a direction different from that of the illumination unit ILU.

[0130] 30B, for example, the light source LS1 may be installed so as to obtain the intensity distribution of the diffracted light by the micromirror Ms in the OFF state. In this case, the driving error of the angle of the micromirror Ms in the OFF state can be measured.

[0131] Even when a separate light source LS1 is provided in this manner, the angle of the micromirror Ms in the on state can be calculated by any of the methods described in the first embodiment and its modifications, and the second embodiment and its modifications. In this case, as described in the first embodiment, the light source LS1 preferably causes a plurality of measurement light beams having different wavelengths to be incident on the DMD 10, and the calculation unit 602 preferably obtains the intensity distribution of the diffracted light for each of two or more conditions in which the measurement light illuminating the DMD 10 has different wavelengths, and calculates the angle of the micromirror Ms in the on state.

[0132] Furthermore, in the above second embodiment and its modified example, the intensity distribution of the diffracted light was obtained using the image sensor 344 provided in the optical measurement unit OMU provided in the calibration reference unit CU, but it is also possible to arrange an image sensor separately from the calibration reference unit CU to obtain the intensity distribution of the diffracted light.

[0133] Furthermore, in the second embodiment and its modified example, the intensity distribution of diffracted light via the projection unit PLU is acquired, but an image of the intensity distribution of diffracted light may be acquired without via the projection unit PLU by providing an image sensor (acquisition device) near the DMD 10. In that case, a lens may be provided between the DMD 10 and the image sensor as shown in FIG. 8A, or no lens may be provided as shown in FIG. 8B.

[0134] The pattern generated by the DMD 10 when measuring the angle of the micromirror Ms in the ON state is not limited to the patterns shown in the first and second embodiments and their modifications. The pattern generated by the DMD 10 when measuring the angle of the micromirror Ms in the ON state may be any pattern that allows the intensity distribution of diffracted light to be obtained, such as the checkerboard pattern shown in Fig. 31(A) or a pattern that turns the micromirror Ms on in an oblique direction as shown in Fig. 31(B).

[0135] Furthermore, in the first and second embodiments and their modifications, the tilt angles of the micromirrors Ms of the DMD 10 are measured in a portion R11 of the region R1 in which the micromirrors Ms are arranged. However, this is not limited to this. For example, the tilt angles of the micromirrors Ms may be measured in multiple regions (e.g., regions obtained by dividing the region R1 into four) of the region R1 in which the micromirrors Ms of the DMD 10 are arranged. In this case, if the angle of the micromirrors Ms in the ON state can be changed for each region, the voltage applied to the micromirrors Ms to be turned on may be changed for each region based on the calculation results of the angle of the micromirrors Ms in the ON state in each region, thereby controlling the angle of the micromirrors Ms in the ON state for each region. Furthermore, the incident angle of the illumination light may be changed for each region. Furthermore, the angle of the micromirrors Ms in the ON state may be calculated for the entire region R1 in which the micromirrors Ms of the DMD 10 are arranged.

[0136] Furthermore, in the above-described first and second embodiments and their modifications, the θy' angle and the θz angle of the micromirror Ms in the on state are calculated, but it is also possible to calculate only one of the θy' angle and the θz angle.

[0137] Furthermore, the angle of the micromirror Ms in the ON state may be measured periodically, and the sticking or failure of the micromirror Ms of the DMD 10 may be predicted based on the amount of deviation from the standard value and its history.

[0138] Furthermore, in the first and second embodiments and their modifications, the micromirror Ms of the DMD 10 transitions between the ON state and the OFF state by rotating about an axis parallel to the diagonal line, but this is not limited to this. The micromirror Ms may transition between the ON state and the OFF state by rotating about an axis parallel to the side. Even if the rotation axis of the micromirror Ms is different from that of the first and second embodiments and their modifications, the angle of the micromirror Ms in the ON state can be calculated using the above-described method.

[0139] In the first and second embodiments and their modifications, the multiple micromirrors Ms of the DMD 10 are arranged in a staggered pattern as shown in Fig. 5A, but they may also be arranged in a square pattern as shown in Fig. 32A. Even in this case, as shown in Fig. 32B, the micromirrors can transition between an ON state and an OFF state by rotating about an axis RAX parallel to the diagonal line.

[0140] The above-described embodiment and modifications are preferred examples of the present invention. However, the present invention is not limited to these, and various modifications are possible within the scope of the present invention. Furthermore, the embodiment and modifications can be combined with each other as appropriate.

[0141] 4B Substrate holder 10 DMD 108 Optical integrator 108B Variable aperture stop 119 Variable aperture stop 119a Opening 119b Light blocking section 500 Measuring device 503 Light source 603 Drive control section CHP Chip CNT Control device EX Exposure device ILm Illumination light ILU Illumination unit LS1 Light source Ms Micro mirror OMU Optical measuring section P Substrate PLU Projection unit

Claims

1. A method comprising: directing measurement light into a spatial light modulator having a plurality of tiltable mirrors arranged in a first state; receiving light from the spatial light modulator; and evaluating the first state based on a relationship between the received light and a reference position.

2. The method according to claim 1, wherein the light is diffracted light, and evaluating the first state includes evaluating the first state based on an intensity distribution of the diffracted light and the reference position.

3. The method of claim 2, wherein the plurality of tiltable mirrors in the first state are a plurality of tiltable mirrors tilted at a first angle, and evaluating the first state includes calculating the first angle.

4. The method of claim 2, wherein the plurality of tiltable mirrors in the first state are tiltable mirrors tilted at a first angle and rotated a first rotation angle with respect to an axis perpendicular to a plane on which the plurality of tiltable mirrors included in the spatial light modulator are arranged, and evaluating the first state includes calculating the first angle and the first rotation angle.

5. The method according to claim 3 or 4, wherein the reference position includes a peak position of diffracted light from the spatial light modulator.

6. The method according to claim 5, wherein the intensity distribution of the diffracted light is an intensity distribution of diffracted light distributed at a first interval, and the diffracted light used as the reference position is diffracted light distributed at a second interval larger than the first interval.

7. The method according to claim 6, wherein the diffracted light used as the reference position is diffracted light from a second region of the first region in which the plurality of tiltable mirrors are arranged, the second region including a tiltable mirror tilted at a second angle different from the first angle.

8. The method according to claim 7, wherein the intensity distribution of the diffracted light and the diffracted light serving as the reference position are obtained by light from the spatial light modulator in which tiltable mirrors in an on-state are arranged at a first pitch and tiltable mirrors in an off-state are arranged at a second pitch smaller than the first pitch.

9. The method of claim 6, wherein the diffracted light used as the reference position is diffracted light from a tiltable mirror in an on state.

10. The method according to claim 9, wherein the intensity distribution of the diffracted light is obtained by light from the spatial light modulator in which the tiltable mirrors in the on state are arranged at a first pitch, and the diffracted light used as the reference position is obtained by light from the spatial light modulator in which the tiltable mirrors in the on state are arranged at a second pitch smaller than the first pitch.

11. The method according to any one of claims 5 to 10, wherein the peak position of the diffracted light that is used as the reference position includes peak positions of a plurality of diffracted lights from the spatial light modulator.

12. A method for adjusting an optical device including a spatial light modulator, comprising adjusting, based on the first state evaluated by the method of claim 1 or claim 2, at least one of the position or angle of at least one optical member in an illumination unit that irradiates illumination light onto the spatial light modulator or a projection unit that projects light from the spatial light modulator, the installation state of the spatial light modulator, and the tilt angle in the on-state of multiple tiltable mirrors of the spatial light modulator.

13. A method for adjusting an optical device including a spatial light modulator, comprising adjusting, based on the first angle calculated by the method of any one of claims 3 to 11, at least one of the position or angle of at least one optical member in an illumination unit that irradiates illumination light onto the spatial light modulator or a projection unit that projects light from the spatial light modulator, the installation state of the spatial light modulator, and the tilt angle in the on state of multiple tiltable mirrors of the spatial light modulator.

14. The adjustment method according to claim 12 or 13, wherein the optical device is an exposure device including the illumination unit, the projection unit, and the spatial light modulator.

15. The adjustment method according to any one of claims 12 to 14, wherein the optical device includes: a light source different from the illumination unit that causes the measurement light to be incident on the spatial light modulator; and an acquisition device that receives the light without passing through a lens.

16. The adjustment method according to any one of claims 12 to 14, wherein the optical device includes: a light source different from the illumination unit that makes the measurement light incident on the spatial light modulator; and an acquisition device that receives the light via a lens.

17. An adjustment method according to any one of claims 12 to 14, wherein the optical device includes a light source different from the illumination unit that causes a plurality of measurement beams having different wavelengths to be incident on the spatial light modulator as the measurement beam.

18. An exposure apparatus comprising: a spatial light modulator including a plurality of tiltable mirrors arranged two-dimensionally; an illumination unit that irradiates illumination light onto the spatial light modulator; a projection unit that irradiates an exposure target with the light from the spatial light modulator; an acquisition device that acquires the intensity distribution of the light from the spatial light modulator; and a control device, wherein the illumination light irradiated onto an on-state mirror among the plurality of tiltable mirrors is incident on the projection unit, and the control device adjusts at least one of the position or angle of at least one optical member in the illumination unit or the projection unit, the position or angle of the spatial light modulator, and the tilt angle of an on-state mirror among the plurality of tiltable mirrors based on the intensity distribution.

19. The exposure apparatus according to claim 18, wherein the control device performs the adjustment based on the positional relationship between the peak position of the intensity distribution and a reference position.

20. The exposure apparatus according to claim 19, wherein the reference position is a peak position of the light from the spatial light modulator.

21. The exposure apparatus according to claim 20, wherein the intensity distribution of the light is an intensity distribution of light distributed at a first interval in the pupil of the projection unit, and the light used as the reference position is light distributed at a second interval in the pupil that is larger than the first interval.

22. The exposure apparatus according to claim 21, wherein the light used as the reference position is light from the plurality of tiltable mirrors in an off state.

23. The exposure apparatus according to claim 22, wherein the acquisition device captures an image including the light having the intensity distribution and the light from the plurality of tiltable mirrors in the off state.

24. The exposure apparatus of claim 23, wherein the image is an image at the pupil of light from the spatial light modulator in which the tiltable mirrors in the on state are arranged at a first pitch and the tiltable mirrors in the off state are arranged at a second pitch that is smaller than the first pitch.

25. The exposure apparatus according to claim 21, wherein the light used as the reference position is light from the plurality of tiltable mirrors in the on state.

26. The exposure apparatus according to claim 24, wherein the acquisition device captures a first image including the light having the intensity distribution and a second image different from the first image including the light from the plurality of tiltable mirrors in the on state.

27. The exposure apparatus of claim 26, wherein the first image is an image at the pupil of light from the spatial light modulator in which the on-state tiltable mirrors are arranged at a first pitch, and the second image is an image at the pupil of light from the spatial light modulator in which the on-state tiltable mirrors are arranged at a second pitch that is smaller than the first pitch.

28. The exposure apparatus according to any one of claims 21 to 27, wherein the acquisition device is located at a position where an imaging plane is conjugate with the pupil.

29. An exposure apparatus according to any one of claims 19 to 28, wherein the projection unit includes a diaphragm located at the position of the pupil of the projection unit, the diaphragm includes an opening that passes light from the spatial light modulator and a light-shielding portion that can block the light, and the reference position is a boundary position between the opening and the light-shielding portion.

30. An exposure apparatus according to any one of claims 18 to 29, comprising a light source different from the illumination unit that irradiates light onto the spatial light modulator, and the light having the intensity distribution is light from the light source that has passed through the spatial light modulator.

31. An exposure apparatus as described in any one of claims 18 to 30, wherein the illumination unit includes a fly's eye lens and an aperture located on the exit surface side of the fly's eye lens and defining the shape of a surface light source formed on the exit surface, and the control device adjusts the aperture to make the size of the surface light source when acquiring the intensity distribution smaller than the size of the surface light source when irradiating light onto the exposure object.

32. An exposure apparatus according to any one of claims 18 to 31, wherein the adjustment comprises adjusting the position or angle of the at least one optical member in the illumination unit to adjust the angle of incidence of the illumination light on the spatial light modulator.

33. The exposure apparatus according to claim 20 or 21, wherein the adjustment is performed so that the peak position of the intensity distribution approaches the peak position of the light.

34. A method for manufacturing an electronic device, comprising: exposing a photosensitive layer located on a substrate using an exposure apparatus according to any one of claims 18 to 33; and developing the exposed photosensitive layer.

Images