Synthetic optical element, lighting unit, exposure device, and exposure method

Abstract

In order to achieve a dichroic mirror having a large area, this synthetic optical element comprises: a plurality of optical elements each provided with a first substrate and a dichroic film; and a second substrate, wherein the plurality of optical elements are disposed on the second substrate.　

Description

Synthetic optical element, illumination unit, exposure apparatus, and exposure method

[0001] The present invention relates to a composite optical element, an illumination unit, an exposure apparatus, and an exposure method.

[0002] In recent years, liquid crystal display panels have come into widespread use as display elements for personal computers, televisions, and other devices. Liquid crystal display panels are manufactured by forming a thin-film transistor circuit pattern on a plate (glass substrate) using photolithography. An exposure apparatus is used for this photolithography process, which projects and exposes an original pattern formed on a mask onto a photoresist layer on the plate via a projection optical system.

[0003] It has been proposed to use a light source using a light emitting diode in various optical devices including the above-mentioned exposure device (for example, Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2006-201476

[0005] According to a first aspect of the disclosure, the composite optical element comprises a first substrate, a plurality of optical elements each comprising a dichroic film, and a second substrate, and the plurality of optical elements are arranged on the second substrate.

[0006] According to a second aspect of the disclosure, the lighting unit includes a first light source that emits light having a first wavelength characteristic, a second light source that emits light having a second wavelength characteristic different from the first wavelength characteristic, the combining optical element, and a light homogenizing element that converts the light beam emitted from the combining optical element into a light beam with a uniform illuminance distribution and emits the converted light, and the dichroic film transmits light having the first wavelength characteristic and reflects light having the second wavelength characteristic.

[0007] According to a third aspect of the disclosure, an exposure apparatus includes the above-mentioned illumination unit and a projection optical system that projects a pattern image of a mask illuminated by the illumination unit onto a photosensitive substrate.

[0008] According to a fourth aspect of the disclosure, an exposure method is an exposure method using the above-mentioned exposure apparatus, and includes illuminating the mask using the illumination unit and projecting a pattern image of the mask onto the photosensitive substrate using the projection optical system.

[0009] 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 allows them to achieve their function, not limited to the placement disclosed in the embodiments.

[0010] FIG. 1 is a schematic diagram showing the configuration of an exposure apparatus according to the first embodiment. FIG. 2 is a schematic diagram showing the configuration of an illumination unit. FIG. 3(A) is a plan view showing the configuration of first and second light source arrays, and FIG. 3(B) is a diagram showing the internal configuration of first and second light source units. FIG. 4(A) is a plan view of a dichroic mirror according to the first embodiment, and FIG. 4(B) is a cross-sectional view taken along line A-A in FIG. 4(A). FIG. 5(A) is a view (top view) of a fly's eye lens as seen from the +Z direction, and FIG. 5(B) is a diagram explaining the relationship between the gaps between small-area dichroic mirrors and the boundaries between lens elements of the fly's eye lens. FIG. 6(A) is a plan view showing a dichroic mirror according to a first modification of the first embodiment, and FIG. 6(B) is a plan view showing a dichroic mirror according to a second modification of the first embodiment. FIG. 7(A) is a plan view showing a dichroic mirror according to Modification 3 of the first embodiment, and FIG. 7(B) is a cross-sectional view taken along line A-A in FIG. 7(A). FIG. 8(A) is a plan view showing a dichroic mirror according to Modification 4 of the first embodiment, and FIG. 8(B) is a cross-sectional view taken along line A-A in FIG. 8(A). FIG. 9(A) is a plan view showing another example of a dichroic mirror according to Modification 4 of the first embodiment, and FIG. 9(B) is a cross-sectional view taken along line A-A in FIG. 9(A). FIGS. 10(A) and 10(B) are diagrams illustrating changes in illuminance of illumination light. FIG. 11(A) is a diagram illustrating the relationship between a fly's eye lens and a small-area dichroic mirror according to the second embodiment, and FIGS. 11(B) and 11(C) are diagrams illustrating changes in illuminance of illumination light according to the second embodiment. FIG. 12 is a plan view showing a dichroic mirror according to Modification 1 of the second embodiment.

[0011] First Embodiment An exposure apparatus 10 according to a first embodiment will be described with reference to FIGS. 1 to 5. FIG.

[0012] (Configuration of Exposure Apparatus) FIG. 1 is a diagram that shows roughly the configuration of an exposure apparatus 10 according to the first embodiment.

[0013] The exposure apparatus 10 is a scanning stepper (scanner) that drives a mask MSK and a glass substrate (hereinafter referred to as "plate") P in the same direction and at the same speed relative to a projection optical system PL, thereby transferring a pattern formed on the mask MSK onto the plate P. The plate P is a rectangular glass substrate used in, for example, a liquid crystal display device (flat panel display), and has at least one side or diagonal length of 500 mm or more.

[0014] In the following, the direction in which the mask MSK and plate P are driven during scanning exposure (scanning direction) is referred to as the X-axis direction, the direction in the horizontal plane perpendicular to this is referred to as the Y-axis direction, the direction perpendicular to the X-axis and Y-axis is referred to as the Z-axis direction, and the rotation (tilt) directions around the X-axis, Y-axis, and Z-axis are referred to as the θx, θy, and θz directions, respectively.

[0015] The exposure apparatus 10 includes an illumination system IOP, a mask stage MST that holds a mask MSK, a projection optical system PL, a body 70 that supports these, a substrate stage PST that holds a plate P, and a control system for these. The control system provides overall control of each component of the exposure apparatus 10.

[0016] The body 70 includes a base (vibration isolation table) 71, columns 72A and 72B, an optical surface plate 73, a support 74, and a slide guide 75. The base (vibration isolation table) 71 is placed on a floor F and supports the columns 72A, 72B, etc., while isolating vibrations from the floor F. The columns 72A and 72B each have a frame shape, with the column 72A being placed inside the column 72B. The optical surface plate 73 has a flat plate shape and is fixed to the ceiling of the column 72A. The support 74 is supported by the ceiling of the column 72B via a slide guide 75. The slide guide 75 includes an air ball lifter and a positioning mechanism, and positions the support 74 (i.e., the mask stage MST, described later) at an appropriate position in the X-axis direction relative to the optical surface plate 73.

[0017] The illumination system IOP is disposed above the body 70. The illumination system IOP irradiates the mask MSK with illumination light IL. The detailed configuration of the illumination system IOP will be described later.

[0018] The mask stage MST is supported by a support 74. A mask MSK having a pattern surface (the lower surface in FIG. 1 ) on which a circuit pattern is formed is fixed to the mask stage MST by, for example, vacuum suction (or electrostatic suction). The mask stage MST is driven by a drive system including, for example, a linear motor at a predetermined stroke in the scanning direction (X-axis direction), and is also driven slightly in the non-scanning directions (Y-axis direction and θz direction).

[0019] Position information of the mask stage MST in the XY plane (including rotation information in the θz direction) is measured by an interferometer system. The interferometer system measures the position of the mask stage MST by irradiating a measurement beam onto a movable mirror (or a mirror-finished reflective surface (not shown)) provided at the end of the mask stage MST and receiving the light reflected from the movable mirror. The measurement results are supplied to a control device (not shown), which drives the mask stage MST via a drive system in accordance with the measurement results of the interferometer system.

[0020] The projection optical system PL is an Offner-type optical system supported by an optical surface plate 73 below (on the -Z side of) the mask stage MST. The projection optical system PL forms, for example, an arc-shaped image field with the Y-axis direction as its longitudinal direction. The projection area of ​​the projection optical system PL is sometimes called the exposure area.

[0021] When an illumination area on the mask MSK is illuminated by illumination light IL from the illumination system IOP, the illumination light IL that has passed through the mask MSK forms a projected image (partial erect image) of the circuit pattern of the mask MSK within that illumination area, via the projection optical system PL, in an irradiation area (exposure area (conjugate to the illumination area)) on a plate P arranged on the image plane side of the projection optical system PL. Here, a resist (sensitizer) is applied to the surface of the plate P. By synchronously driving the mask stage MST and the substrate stage PST, i.e., by driving the mask MSK in the scanning direction (X-axis direction) relative to the illumination area (illumination light IL) and driving the plate P in the same scanning direction relative to the exposure area (illumination light IL), the plate P is exposed and the pattern of the mask MSK is transferred onto the plate P.

[0022] The substrate stage PST is placed on a base (vibration isolation table) 71 below (on the -Z side of) the projection optical system PL. A plate P is held on the substrate stage PST via a substrate holder (not shown).

[0023] Position information of the substrate stage PST in the XY plane (including rotation information (yawing amount (rotation amount θz in the θz direction), pitching amount (rotation amount θx in the θx direction), and rolling amount (rotation amount θy in the θy direction))) is measured by an interferometer system. The interferometer system measures the position of the substrate stage PST by irradiating a measurement beam from the optical surface plate 73 onto a movable mirror (or a mirror-finished reflective surface (not shown)) provided at the end of the substrate stage PST, and receiving the reflected light from the movable mirror. The measurement results are supplied to a control device (not shown), and the control device drives the substrate stage PST in accordance with the measurement results of the interferometer system.

[0024] In exposure apparatus 10, alignment measurement (e.g., EGA, etc.) is performed prior to exposure, and the plate P is exposed using the results in the following procedure. First, in accordance with instructions from the control device, the mask stage MST and substrate stage PST are synchronously driven in the X-axis direction. This performs scanning exposure on the first shot area on plate P. When scanning exposure on the first shot area is completed, the control device moves (steps) the substrate stage PST to a position corresponding to the second shot area. Then, scanning exposure is performed on the second shot area. In the same manner, the control device repeats stepping between shot areas of plate P and scanning exposure on the shot areas to transfer the pattern of the mask MSK to all shot areas on plate P.

[0025] (Configuration of illumination system IOP) Next, the configuration of illumination system IOP in this embodiment will be described. Illumination system IOP includes an illumination unit 90. FIG.

[0026] The illumination unit 90 includes a first light source unit OPU1, a second light source unit OPU2, an illumination optical system 80, and a control unit CU.

[0027] (Configuration of Light Source Unit) The first light source unit OPU1 includes a first light source array 20A and a first magnifying optical system 30A, and the second light source unit OPU2 includes a second light source array 20B and a second magnifying optical system 30B.

[0028] FIG. 3A is a plan view schematically illustrating the configuration of the first light source array 20A and the second light source array 20B. The first light source array 20A includes a plurality of LED (Light Emitting Diode) chips 23A (5 x 5 in FIG. 3A) arranged on a substrate 21A, for example. The number of LED chips 23A may be changed as needed. Each of the LED chips 23A has a light-emitting portion 231A, and the peak wavelength of light emitted from the light-emitting portion 231A is in the range of 380 to 390 nm. In other words, the light-emitting portion 231A is an ultraviolet LED (UV LED). More preferably, the peak wavelength of light emitted from the light-emitting portion 231A is 385 nm. The light-emitting surface of the light-emitting portion 231A is square, and the length of one side is a1. The LED chips 23A are arranged at a pitch P1, which is the distance between the centers of adjacent LED chips 23A.

[0029] The second light source array 20B includes a plurality of LED chips 23B (5 x 5 in FIG. 3A) arranged on a substrate 21B, for example. The number of LED chips 23B may be changed appropriately as needed. Each of the plurality of LED chips 23B has a light-emitting portion 231B, and the peak wavelength of the light emitted from the light-emitting portion 231B is in the range of 360 to 370 nm. In other words, the light-emitting portion 231B is a UV LED. It is more preferable that the peak wavelength of the light emitted from the light-emitting portion 231B is 365 nm. The light-emitting surface of the light-emitting portion 231B is square, and the length of one side is a2. The LED chips 23B are arranged at a pitch P2.

[0030] The arrangement pitch P1 of the LED chips 23A and the arrangement pitch P2 of the LED chips 23B may be the same or different. Furthermore, the length a1 of one side of the light-emitting surface of the light-emitting portion 231A and the length a2 of one side of the light-emitting surface of the light-emitting portion 231B may be the same or different. The LED chips 23A and 23B may be arranged on, for example, a heat sink, rather than on a substrate.

[0031] The control unit CU controls the current value supplied to each of the light emitting portion 231A of the LED chip 23A and the light emitting portion 231B of the LED chip 23B, and adjusts the intensity of the light emitted from each of the light emitting portion 231A and the light emitting portion 231B.

[0032] FIG. 3B is a diagram schematically illustrating the internal configuration of the first light source unit OPU1 and the second light source unit OPU2. Since the internal configurations of the first light source unit OPU1 and the second light source unit OPU2 are identical, the configuration of the first light source unit OPU1 will be described here. The two directions in which the LED chips 23A are arranged are defined as the X1 direction and the Y1 direction. The X1 direction and the Y1 direction are orthogonal to each other. The direction orthogonal to the X1 direction and the Y1 direction is defined as the Z1 direction. The Z1 direction is approximately parallel to the optical axis OA of the light emitted by the light-emitting portion 231A. For clarity of illustration, FIG. 3B shows only four LED chips 23A aligned in a row along the Y1 direction.

[0033] 3B, the first magnifying optical system 30A is an optical system for forming a magnified image of the light-emitting portion 231A of each LED chip 23A on a predetermined plane PP. The first magnifying optical system 30A includes a plurality of lens units 31A arranged to correspond to the arrangement of the LED chips 23A. Each of the lens units 31A is a double-telecentric optical system that magnifies and projects the light-emitting portion 231A at a magnification M1.

[0034] In this embodiment, each lens portion 31A includes four plano-convex lenses, but is not limited to this, and each lens portion 31A may include, for example, two biconvex lenses, three biconvex lenses, or a plano-convex lens and a biconvex lens.

[0035] In this embodiment, the lens unit 31A magnifies and projects the light-emitting units 231A at a magnification M1, for example. The magnification M1 is, for example, (arrangement pitch P1 of the LED chips 23A) / (length a1 of one side of the light-emitting surface of the light-emitting units 231A). In this case, the magnified images of the multiple light-emitting units 231A are substantially in contact with each other on the predetermined plane PP. Note that the magnification M1 may be greater than (arrangement pitch P1 of the LED chips 23A) / (length a1 of one side of the light-emitting surface of the light-emitting units 231A).

[0036] Meanwhile, the lens unit 31B included in the second magnifying optical system 30B enlarges and projects the light-emitting units 231B at a magnification M2, for example. The magnification M2 is, for example, (arrangement pitch P2 of the LED chips 23B) / (length a2 of one side of the light-emitting surface of the light-emitting units 231B). In this case, the enlarged images of the multiple light-emitting units 231B are substantially in contact with each other on the predetermined plane PP. Note that the magnification M2 may be greater than (arrangement pitch P2 of the LED chips 23B) / (length a2 of one side of the light-emitting surface of the light-emitting units 231B).

[0037] 2, the following describes the configuration of the illumination optical system 80. The illumination optical system 80 includes a first focusing optical system 81A, a second focusing optical system 81B, a dichroic mirror DM, an imaging optical system 83, a fly's eye lens FEL, an aperture stop 85, and a condenser optical system 84.

[0038] The first focusing optical system 81A is disposed on or near the predetermined plane PP, and forms a pupil of the enlarged image of the light-emitting unit 231A formed by the first magnifying optical system 30A. The first focusing optical system 81A may be composed of a single lens or a lens group including a plurality of lenses.

[0039] The second focusing optical system 81B is disposed on or near the predetermined plane PP, and forms a pupil of the magnified image of the light-emitting unit 231B formed by the second magnifying optical system 30B. The second focusing optical system 81B may be composed of a single lens or a lens group including a plurality of lenses.

[0040] The dichroic mirror DM transmits at least a portion of the light with a peak wavelength of 385 nm and reflects at least a portion of the light with a peak wavelength of 365 nm. As a result, a composite image is formed by superimposing the pupil image formed by the first focusing optical system 81A and the pupil image formed by the second focusing optical system 81B, and the dichroic mirror DM provides Koehler illumination to the first focusing optical system 81A and the second focusing optical system 81B. Note that the configuration is not limited to this embodiment, and the first focusing optical system 81A and the second focusing optical system 81B may be configured to perform critical illumination that forms an image of the first light source unit OPU1 and an image of the second light source unit OPU2 on the dichroic mirror DM, respectively.

[0041] In this embodiment, the illumination field size on the mask surface of the illumination optical system 80 is, for example, 750 mm × 200 mm or more, and may be 880 mm × 245 mm or more. In this case, in order to ensure the combining efficiency of the light from the first light source unit OPU1 and the light from the second light source unit OPU2 and to suppress a decrease in illuminance, a large dichroic mirror DM having a size of, for example, 325 mm × 300 mm or more is required. The size of the dichroic mirror DM may be, for example, 342 mm × 315 mm or more.

[0042] For example, radical assisted sputtering (RAS) is used to form high-quality dichroic films. However, due to the configuration of a RAS sputtering apparatus, it is difficult to form a large-area dichroic film.

[0043] Therefore, in this embodiment, a large-area dichroic mirror DM is realized by bonding together a plurality of small-area dichroic mirrors SDM.

[0044] (Configuration of Dichroic Mirror DM) FIG. 4A is a plan view of the dichroic mirror DM according to the first embodiment, and FIG. 4B is a cross-sectional view taken along line AA of FIG. 4A.

[0045] As shown in FIG. 4A, the dichroic mirror DM includes a plurality of small-area dichroic mirrors SDM (four in FIG. 4A).

[0046] 4B , each small-area dichroic mirror SDM includes a substrate 51 and a dichroic film 52. The dichroic film 52 is formed on a first surface 51 a of the substrate 51. The substrate 51 is a light-transmitting substrate. Considering the peak wavelengths of the light emitted by the light-emitting portions 231A and 231B of the LED chips 23A and 23B, the substrate 51 is preferably, for example, a quartz glass substrate.

[0047] The multiple small-area dichroic mirrors SDM are arranged on a first surface 50a of a substrate 50 having an area larger than the small-area dichroic mirrors SDM. As described above, in order to ensure the combining efficiency of the light from the first light source unit OPU1 and the light from the second light source unit OPU2 and to suppress a decrease in illuminance, a large dichroic mirror DM having a size of 325 mm x 300 mm or more is required. Therefore, the length of each side of the substrate 50 is at least 300 mm or more. In this embodiment, the multiple small-area dichroic mirrors SDM are arranged at a distance from each other.

[0048] The substrate 50 is a light-transmitting substrate. As a result, light coming from the second surface 50b of the substrate 50 (the surface opposite to the first surface 50a) is incident on the multiple small-area dichroic mirrors SDM. Considering the peak wavelengths of the light emitted by the light-emitting portions 231A and 231B of the LED chips 23A and 23B, the substrate 50 is preferably a quartz glass substrate, for example. The substrates 51 and 50 may be made of the same material or different materials.

[0049] The small-area dichroic mirror SDM is fixed to the substrate 50 by, for example, an adhesive. The method of fixing the small-area dichroic mirror SDM to the substrate 50 is not limited to adhesive. For example, the second surface 51b of the substrate 51 opposite to the first surface 51a on which the dichroic film 52 is formed and the first surface 50a of the substrate 50 may be polished with high precision, and the substrate 50 and the small-area dichroic mirror SDM may be joined by optical contact. The small-area dichroic mirror SDM may also be fixed to the substrate 50 by a leaf spring or the like.

[0050] As described above, in this embodiment, a large-area dichroic mirror DM is realized by bonding multiple small-area dichroic mirrors SDM to the substrate 50. As a result, the illumination optical system 80 can achieve an illumination field size of 750 mm × 200 mm or more, or 880 mm × 245 mm or more, on the mask plane. The dichroic mirror DM may be positioned so that light from the first light source unit OPU1 is incident on the side on which the dichroic film 52 is formed, or so that light from the first light source unit OPU1 is incident on the side opposite to the side on which the dichroic film 52 is formed (i.e., the second surface 50b side).

[0051] 2, the imaging optical system 83 is a double-telecentric optical system that projects the composite image formed by the dichroic mirror DM onto the incident end of the fly-eye lens FEL at an equal magnification. Note that the imaging optical system 83 may also reduce and project the composite image formed by the dichroic mirror DM onto the incident end of the fly-eye lens FEL.

[0052] 5A is a diagram (top view) of the fly-eye lens FEL as viewed from the +Z direction. As shown in FIG. 5A, the fly-eye lens FEL is configured by closely arranging a large number of lens elements 60 having, for example, positive refractive power, vertically and horizontally so that their optical axes are parallel to the reference optical axis AX (see FIG. 2). Each lens element 60 constituting the fly-eye lens FEL has a rectangular cross section similar to the shape of the illumination field to be formed on the mask MSK (and consequently the shape of the exposure area to be formed on the plate P).

[0053] 5B is a diagram illustrating the relationship between the gaps between the small area dichroic mirrors SDM and the boundaries between the lens elements 60 of the fly-eye lens FEL. In FIG. 5B, the fly-eye lens FEL is indicated by a dashed line.

[0054] In this embodiment, in order to suppress a decrease in the illuminance uniformity of the illumination light IL, the dichroic mirrors DM are arranged so that, in a planar view (top view), the gap between adjacent small-area dichroic mirrors SDM overlaps with the boundary 61 between the multiple lens elements 60 provided in the fly-eye lens FEL, as shown in Figure 5 (B).

[0055] If the gap between the small area dichroic mirrors SDM overlaps with a portion that does not include the boundary 61 of the lens element 60, the illuminance of the illumination light IL will decrease in that portion, and the light homogenizing function of the fly-eye lens FEL will not be fully exerted, resulting in a decrease in the illuminance uniformity of the illumination light IL.

[0056] By arranging the dichroic mirrors DM as in this embodiment, the gap between the small-area dichroic mirrors SDM and the area where the lens element 60 overlaps can be minimized, thereby suppressing a decrease in the illuminance uniformity of the illumination light IL.

[0057] 2, the light beam incident on the fly-eye lens FEL is wavefront split by the multiple lens elements 60, and one light source image is formed on or near the rear focal plane of each lens element 60. In other words, a substantial surface light source, i.e., a secondary light source, consisting of multiple light source images is formed on or near the rear focal plane of the fly-eye lens FEL. The light beam from the secondary light source formed on or near the rear focal plane of the fly-eye lens FEL is incident on an aperture stop 85 arranged nearby.

[0058] The aperture stop 85 is disposed at a position that is nearly optically conjugate with the entrance pupil plane of the projection optical system PL, and has a variable opening for defining the range that contributes to illumination from the secondary light source. The aperture stop 85 changes the aperture diameter of the variable opening to set the σ value (the ratio of the aperture diameter of the secondary light source image on the pupil plane of the projection optical system to the aperture diameter of the pupil plane) that determines the illumination conditions to a desired value. The light from the secondary light source that passes through the aperture stop 85 is subjected to the focusing action of the condenser optical system 84, and then illuminates a mask MSK on which a predetermined pattern is formed in a superimposed manner.

[0059] As described above, when the illumination area on the mask MSK is illuminated by the illumination light IL from the illumination system IOP, the illumination light IL that has passed through the mask MSK forms a projected image (partial erect image) of the circuit pattern of the mask MSK within the illumination area in an irradiation area (exposure area (conjugate to the illumination area)) on the plate P that is arranged on the image plane side of the projection optical system PL. This exposes the plate P, and the pattern of the mask MSK is transferred onto the plate P.

[0060] As described above in detail, according to the first embodiment, the dichroic mirror DM includes a plurality of small-area dichroic mirrors SDM each including a substrate 51 and a dichroic film 52, and a substrate 50 having a first surface 50a on which the plurality of small-area dichroic mirrors SDM are arranged, and which causes light coming from a second surface 50b opposite the first surface 50a to be incident on the plurality of small-area dichroic mirrors SDM. Because the small-area dichroic mirrors SDM are combined in a size that is easy to manufacture, it is easy to manufacture a large-sized dichroic mirror DM. Furthermore, it is possible to realize a dichroic mirror DM of a size (area) that makes it difficult to form a dichroic film using a RAS-type sputtering device.

[0061] In the first embodiment, the illumination unit 90 includes a first light source unit OPU1 that emits light with a peak wavelength of 385 nm, a second light source unit OPU2 that emits light with a peak wavelength of 365 nm, a dichroic mirror DM, and a fly's eye lens FEL that converts the light beam emitted from the dichroic mirror DM into a light beam with a uniform illuminance distribution and emits the converted light, and the dichroic film 52 transmits the light with a peak wavelength of 385 nm and reflects the light with a peak wavelength of 365 nm. This allows the light beams with different peak wavelengths to be combined to form the illumination light IL.

[0062] Furthermore, in the first embodiment, the fly-eye lens FEL has a plurality of lens elements (60), and in plan view, the gaps between adjacent small-area dichroic mirrors SDM among the small-area dichroic mirrors SDM overlap with the boundaries 61 between the lens elements 60. This makes it possible to prevent the illuminance of the illumination light IL from becoming non-uniform.

[0063] In the first embodiment, the first light source unit OPU1 includes a first light source array 20A in which a plurality of LED chips 23A each having a light-emitting portion 231A that emits light with a peak wavelength of 385 nm are arranged, and the second light source unit OPU2 includes a second light source array 20B in which a plurality of LED chips 23B each having a light-emitting portion 231B that emits light with a peak wavelength of 365 nm are arranged. This allows for reduced power consumption in the first light source unit OPU1 and the second light source unit OPU2 compared to when, for example, a mercury lamp is used instead of LED chips.

[0064] In the first embodiment, the dichroic film 52 may transmit light with a peak wavelength of 365 nm and reflect light with a peak wavelength of 385 nm. In this case, the first light source unit OPU1 emits light with a peak wavelength of 365 nm, and the second light source unit OPU2 emits light with a peak wavelength of 385 nm.

[0065] The wavelengths of the light emitted by the first light source unit OPU1 and the second light source unit OPU2 are not limited to those described above, and the first light source unit OPU1 and the second light source unit OPU2 may be configured by appropriately combining LED chips that emit light having a peak wavelength in the range of 360 to 440 nm. For example, the first light source unit OPU1 may be configured to emit light with a peak wavelength of 405 nm, and the second light source unit OPU2 may be configured to emit light with a peak wavelength of 385 nm. Alternatively, the first light source unit OPU1 may be configured to emit light with a peak wavelength of 395 nm, and the second light source unit OPU2 may be configured to emit light with a peak wavelength of 385 nm. The combinations of the wavelengths of the light emitted by the first light source unit OPU1 and the second light source unit OPU2 are not limited to these examples. In addition, if the combination of the wavelength of light emitted by the first light source unit OPU1 and the wavelength of light emitted by the second light source unit OPU2 is a combination other than that in the first embodiment, it is preferable to change the material of the dichroic film 52 appropriately depending on the wavelength used.

[0066] (Modification) Next, a modification of the dichroic mirror DM will be described.

[0067] 6A is a plan view showing a dichroic mirror DM1 according to Modification 1 of the first embodiment. As shown in FIG. 6A, in the dichroic mirror DM1 according to Modification 1, adjacent small-area dichroic mirrors SDM1 are arranged so as to be in contact with each other. In this way, there may be no gap between adjacent small-area dichroic mirrors SDM1. The rest of the configuration is the same as in the first embodiment, so detailed description will be omitted.

[0068] FIG. 6B is a plan view showing a dichroic mirror DM2 according to Modification 2 of the first embodiment. As shown in FIG. 6B, in the dichroic mirror DM2 according to Modification 2, the planar shape of the small-area dichroic mirror SDM2 is not rectangular but fan-shaped. As such, the planar shape of the small-area dichroic mirror SDM2 does not have to be rectangular. Note that in Modification 2, there is no gap between adjacent small-area dichroic mirrors SDM2, but adjacent small-area dichroic mirrors SDM2 may be spaced apart. Since the other configurations are the same as those of the first embodiment, detailed description thereof will be omitted.

[0069] Fig. 7A is a plan view showing a dichroic mirror DM3 according to Modification 3 of the first embodiment, and Fig. 7B is a cross-sectional view taken along line A-A in Fig. 7A. As shown in Fig. 7A, in the dichroic mirror DM3 according to Modification 3, the substrate 50A is a non-light-transmitting substrate and has one opening 54A in the center. Each small-area dichroic mirror SDM3 is arranged so that at least a portion thereof overlaps with the opening 54A in plan view.

[0070] The substrate 50A has an opening 54A in the center, allowing light coming from the second surface 50b of the substrate 50A to be incident on the multiple small-area dichroic mirrors SDM3 through the opening 54A. In this way, the substrate 50A may be a non-light-transmitting substrate. For example, the substrate 50A may be a metal substrate or a resin substrate. The other configurations are the same as those of the first embodiment, so detailed description will be omitted. While adjacent small-area dichroic mirrors SDM3 are in contact with each other in FIG. 7A, there may be gaps between adjacent small-area dichroic mirrors SDM3.

[0071] Fig. 8A is a plan view showing a dichroic mirror DM4 according to a fourth modification of the first embodiment, and Fig. 8B is a cross-sectional view taken along line A-A in Fig. 8A. As shown in Fig. 8A, in the dichroic mirror DM4 according to the fourth modification, the substrate 50B is a non-light-transmitting substrate and has a plurality of openings 54B. Crosspieces 57 are provided between the plurality of openings 54B.

[0072] 8B, a plurality of small-area dichroic mirrors SDM4 are provided to correspond to the plurality of openings 54B, respectively. In this manner, since the substrate 50B has a plurality of openings 54B, light coming from the second surface 50b side of the substrate 50B can be made incident on the plurality of small-area dichroic mirrors SDM4 through the openings 54B.

[0073] In the fourth modification, a plurality of small-area dichroic mirrors SDM4 are provided so as to correspond to the plurality of openings 54B, respectively, but as shown in Figures 9(A) and 9(B), for example, one small-area dichroic mirror SDM4 may correspond to two openings 54B. Since the other configurations are the same as those in the first embodiment, detailed description thereof will be omitted.

[0074] In the first embodiment and its variants 1 to 4, the dichroic mirror was provided with four small-area dichroic mirrors, but as shown in another example of variant 4, the number of small-area dichroic mirrors provided in the dichroic mirror is not limited to four, and may be two or more.

[0075] When using the dichroic mirrors DM1 to DM3 of variants 1 to 3, the dichroic mirrors DM1 to DM3 are arranged so that the boundary 55 between adjacent small-area dichroic mirrors SDM1 to SDM3 overlaps with the boundary 61 between the lens elements 60 of the fly-eye lens FEL.

[0076] Furthermore, when using the dichroic mirror DM4 of variant example 4 and its other examples, the dichroic mirror DM4 can be positioned so that the crosspieces 57 present between the openings 54B of the substrate 50B overlap with the boundaries 61 between the lens elements 60 of the fly-eye lens FEL.

[0077] Second Embodiment In the first embodiment and its modified examples, the dichroic mirrors are arranged so that the boundaries between adjacent small-area dichroic mirrors or the gaps between adjacent small-area dichroic mirrors overlap with the boundaries 61 between the lens elements 60 of the fly-eye lens FEL. In this case, for example, if the dichroic mirror DM is misaligned, the illuminance of the illumination light IL emitted by the illumination unit 90 decreases.

[0078] This point will be explained using Figures 10(A) and 10(B). Figure 10(A) shows a state in which the gap between adjacent small-area dichroic mirrors SDM overlaps with the boundary 61 between the lens elements 60 of the fly-eye lens FEL, and Figure 10(B) shows a state in which the gap between adjacent small-area dichroic mirrors SDM no longer overlaps with the boundary 61 between the lens elements 60 of the fly-eye lens FEL due to a positional shift of the dichroic mirrors DM.

[0079] In the case of Figure 10 (B), the gap between adjacent small-area dichroic mirrors SDM overlaps with the lens element 60 of the fly-eye lens FEL, reducing the amount of light incident on the lens element 60 and reducing the illuminance of the illumination light IL.

[0080] 11A is a diagram illustrating the relationship between the fly-eye lens FEL and the small-area dichroic mirror SDM in the second embodiment. In the second embodiment, as shown in FIG. 11A, the dichroic mirror DM is arranged so that, in a plan view, each side 56 of the small-area dichroic mirror SDM diagonally intersects with the boundary 61 between the lens elements 60 of the fly-eye lens FEL. In other words, the dichroic mirror DM is arranged so that the portion corresponding to the gap between the small-area dichroic mirrors SDM diagonally crosses the boundary 61 between the lens elements 60.

[0081] In this case, as shown in Figures 11(B) and 11(C), even if the dichroic mirror DM is misaligned, the area where the portion corresponding to the gap between the small-area dichroic mirrors SDM overlaps with the lens element 60 remains almost unchanged before and after the misalignment, so the change in illuminance can be made smaller than in the case shown in Figures 10(A) and 10(B).

[0082] The other configurations are the same as those of the first embodiment, and therefore detailed description thereof will be omitted. Note that the configuration of the second embodiment can also be applied to the first to fourth modifications of the first embodiment.

[0083] (Modification) In the first and second embodiments, the plurality of small-area dichroic mirrors have the same shape and size and are arranged regularly, but the present invention is not limited to this.

[0084] 12 is a plan view showing a dichroic mirror DM5 according to a first modification of the second embodiment. As shown in Fig. 12, the dichroic mirror DM5 includes a plurality of small-area dichroic mirrors SDMa, SDMb, SDMc, SDMd, ... having different sizes. The small-area dichroic mirrors SDMa, SDMb, SDMc, SDMd, ... are randomly arranged in a plan view so that each side 56 obliquely intersects with the boundary 61 between the lens elements 60 of the fly's eye lens FEL. It is sufficient that at least two of the plurality of small-area dichroic mirrors have different sizes.

[0085] In this way, even if a plurality of small-area dichroic mirrors are arranged in a mosaic pattern, it is possible to suppress a change in illuminance when the dichroic mirrors are misaligned.

[0086] In the first embodiment and its modified examples, at least two of the plurality of small-area dichroic mirrors may have different sizes.

[0087] In the first and second embodiments and their modifications, the multiple small-area dichroic mirrors may have different film characteristics due to manufacturing errors during film formation, etc. In this case, the film characteristics of each small-area dichroic mirror may be measured in advance, and the control unit CU may adjust the intensity of light emitted by each light-emitting unit 231A of the first light source array 20A and the intensity of light emitted by each light-emitting unit 231B of the second light source array 20B according to the film characteristics of each small-area dichroic mirror. This allows more uniform illumination light IL to be irradiated onto the mask MSK.

[0088] The above-described embodiment is a preferred example of the present invention, but the present invention is not limited to this and can be modified in various ways without departing from the spirit of the present invention.

[0089] 10 Exposure device 20A First light source array 20B Second light source array 23A, 23B LED chip 50, 50A, 50B Substrate 50a First surface 50b Second surface 51 Substrate 52 Dichroic film 54A, 54B Opening 60 Lens element 61 Boundary 90 Illumination unit 231A, 231B Light emitting section DM, DM1, DM2, DM3, DM4, DM5 Dichroic mirror FEL Fly's eye lens MSK Mask OPU1 First light source unit OPU2 Second light source unit PL Projection optical system SDM, SDM1, SDM2, SDM3, SDMa, SDMb, SDMc, SDMd Small area dichroic mirror P Glass substrate

Claims

1. A first substrate, a plurality of optical elements including a dichroic film, a second substrate, comprising: A synthetic optical element in which the plurality of optical elements are arranged on the second substrate.

2. The second substrate has a first surface on which the plurality of optical elements are arranged and a second surface on the opposite side of the first surface, and guides light incident from the second surface side to the plurality of optical elements. The synthetic optical element according to claim 1.

3. The plurality of optical elements are regularly arranged on the first surface of the second substrate. The synthetic optical element according to claim 2.

4. The plurality of optical elements are randomly arranged on the first surface of the second substrate. The synthetic optical element according to claim 2.

5. At least two of the plurality of optical elements have different sizes from each other. The synthetic optical element according to any one of claims 1 to 4.

6. The first substrate and the second substrate are light-transmissive substrates. The synthetic optical element according to any one of claims 1 to 4.

7. The first substrate and the second substrate are quartz glass substrates. The synthetic optical element according to claim 6.

8. The first substrate is a light-transmissive substrate. The second substrate is a light-non-transmissive substrate. The second substrate has an opening. In a plan view, at least a part of each of the plurality of optical elements overlaps with the opening. The synthetic optical element according to any one of claims 1 to 4.

9. The second substrate has a plurality of openings. At least a part of each of the plurality of optical elements overlaps with at least one of the plurality of openings. The synthetic optical element according to claim 8.

10. The second substrate has a rectangular shape. The length of each side of the second substrate is at least 300 mm or more. The synthetic optical element according to any one of claims 1 to 4.

11. The size of the second substrate is larger than the upper limit size at which a dichroic film can be formed in a RAS type sputtering apparatus. The synthetic optical element according to any one of claims 1 to 4.

12. A first light source that emits light having a first wavelength characteristic, A second light source that emits light having a second wavelength characteristic different from the first wavelength characteristic, A synthetic optical element according to any one of claims 1 to 4, A light homogenizing element that emits the light beam emitted from the synthetic optical element as a light beam having a uniform illuminance distribution. comprising: The dichroic film transmits light having the first wavelength characteristic and reflects light having the second wavelength characteristic. Illumination unit.

13. The light homogenizing element is a fly-eye lens having a plurality of lens elements, In a plan view seen from the reference optical axis direction of the fly-eye lens, the boundary between adjacent optical elements among the plurality of optical elements, or the gap between the adjacent optical elements overlaps with the boundary between the plurality of lens elements. The illumination unit according to claim 12.

14. The light homogenizing element is a fly-eye lens having a plurality of lens elements, In a plan view seen from the reference optical axis direction of the fly-eye lens, each side of the plurality of optical elements intersects obliquely with respect to the boundary between the plurality of lens elements. The illumination unit according to claim 12.

15. The first light source includes a first light source array in which a plurality of first light source elements each having a first light emitting portion that emits light having the first wavelength characteristic are arranged, The second light source includes a second light source array in which a plurality of second light source elements each having a second light emitting portion that emits light having the second wavelength characteristic are arranged. The illumination unit according to claim 12.

16. The illumination unit according to claim 15, further comprising an adjustment unit that adjusts the intensity of light emitted by each of the first light emitting portions and the intensity of light emitted by each of the second light emitting portions based on the optical characteristics of each of the plurality of optical elements.

17. The illumination unit according to claim 12, A projection optical system that projects a pattern image of a mask illuminated by the illumination unit onto a photosensitive substrate, An exposure apparatus comprising:

18. The photosensitive substrate has a length of at least one side or a diagonal length of 500 mm or more. The exposure apparatus according to claim 17.

19. An exposure method using the exposure apparatus according to claim 17, Illuminating the mask using the illumination unit, Projecting a pattern image of the mask onto the photosensitive substrate using the projection optical system, An exposure method including: