Light source unit, illumination unit, exposure device, and exposure method

Abstract

This light source unit comprises: a plurality of light source elements that are two-dimensionally arranged on a surface of a fixation target; and protruding portions that protrude from the fixation target and that are each provided between one of the plurality of light source elements and at least one of the other light source elements adjacent to said one light source element. The ends of the protruding portions are located at a position higher than the lower surfaces of the light source elements.　

Description

Light source unit, illumination unit, exposure apparatus, and exposure method

[0001] The present invention relates to a light source unit, 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 the like. Liquid crystal display panels are manufactured by forming a circuit pattern of thin-film transistors on a plate (glass substrate) using a photolithography technique. 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 (see, for example, Patent Document 1).

[0003] In general, there is a demand for a high-brightness surface light source that can be applied to various optical devices, including the above-mentioned exposure device.

[0004] Japanese Patent Application Laid-Open No. 2000-21712

[0005] According to the first aspect of the disclosure, the light source unit comprises a plurality of light source elements arranged two-dimensionally on the surface of a fixed object, and a protrusion protruding from the fixed object and provided between each light source element of the plurality of light source elements and at least one other light source element adjacent to each light source element, and the end of the protrusion is located at a position higher than the underside of each light source element.

[0006] According to a second aspect of the disclosure, an illumination unit includes the light source unit and an illumination optical system that guides light emitted from the light source unit to an object to be illuminated.

[0007] According to a third aspect of the disclosure, the lighting unit includes a plurality of the above-mentioned light source units, and an illumination optical system that includes a combining optical element that combines light emitted from the plurality of light source units and guides the combined light emitted from the combining optical element to an illuminated object.

[0008] According to a fourth 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.

[0009] According to a fifth aspect of the disclosure, an exposure method is an exposure method using the above-mentioned exposure apparatus, and includes illuminating a mask with the illumination unit and projecting a pattern image of the mask onto a photosensitive substrate using the projection optical system.

[0010] 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.

[0011] FIG. 1 is a schematic diagram showing the configuration of an exposure apparatus according to an embodiment. FIG. 2 is a schematic diagram showing the configuration of an illumination unit. FIG. 3A is a plan view showing the configuration of first and second light source arrays, and FIG. 3B is a view showing the internal configuration of the first and second light source units. FIG. 4A is a plan view showing a substrate according to an embodiment, and FIG. 4B is a cross-sectional view taken along line A-A in FIG. 4A. FIGS. 5A to 5H are diagrams showing a manufacturing method for the first light source array. FIG. 6A is a plan view showing an example of a protrusion according to Modification 1, and FIG. 6B is a cross-sectional view taken along line A-A in FIG. 6A. FIG. 7A is a plan view showing an example of a protrusion according to Modification 2, and FIG. 7B is a cross-sectional view taken along line A-A in FIG. 7A. FIG. 8A is a plan view showing an example of a protrusion according to Modification 3, and FIG. 8B is a cross-sectional view taken along line A-A in FIG. 8A.

[0012] An exposure apparatus 10 according to one embodiment will be described with reference to FIGS.

[0013] (Configuration of Exposure Apparatus) First, the configuration of an exposure apparatus 10 according to one embodiment will be described using Fig. 1. Fig. 1 is a diagram that shows schematically the configuration of an exposure apparatus 10 according to one embodiment.

[0014] The exposure apparatus 10 is a scanning stepper (scanner) that drives a mask MSK and a glass substrate (hereinafter referred to as "substrate") 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 substrate P. The substrate P is a rectangular glass substrate used in, for example, a liquid crystal display device (flat panel display), with at least one side or diagonal length of 500 mm or more.

[0015] In the following, the direction in which the mask MSK and substrate 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.

[0016] 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 substrate P, and a control system for these. The control system provides overall control of each component of the exposure apparatus 10.

[0017] 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.

[0018] 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.

[0019] 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).

[0020] 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.

[0021] The projection optical system PL is supported on an optical surface plate 73 below (on the -Z side of) the mask stage MST. The projection optical system PL is configured similarly to the projection optical system disclosed in, for example, U.S. Pat. No. 5,729,331. The projection optical system PL includes multiple (e.g., seven) projection optical units 100 (multi-lens projection optical units) arranged, for example, in a staggered pattern, to project the pattern image of the mask MSK. This forms a rectangular image field with the Y-axis direction as its longitudinal direction. Here, four projection optical units 100 are arranged at predetermined intervals in the Y-axis direction, and the remaining three projection optical units 100 are arranged at predetermined intervals in the Y-axis direction, spaced apart from the four projection optical units 100 on the +X side. Each of the multiple projection optical units 100 is, for example, a bilaterally telecentric, 1x1 system that forms an erect, normal image. The multiple projection areas of the staggered projection optical units 100 are collectively referred to as the exposure area.

[0022] When the 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 the substrate P, which is arranged on the image plane side of the projection optical system PL. Here, a resist (sensitizer) is applied to the surface of the substrate 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 substrate P in the same scanning direction relative to the exposure area (illumination light IL), the substrate P is exposed and the pattern of the mask MSK is transferred onto the substrate P.

[0023] The substrate stage PST is disposed on a base (vibration isolation table) 71 below (on the -Z side of) the projection optical system PL. The substrate P is held on the substrate stage PST via a substrate holder (not shown).

[0024] 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.

[0025] In exposure apparatus 10, alignment measurement (for example, EGA, etc.) is performed prior to exposure, and the results are used to expose substrate P in the following procedure. First, in accordance with instructions from the control device, 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 substrate P. When scanning exposure on the first shot area is completed, the control device moves (steps) substrate stage PST to a position corresponding to the second shot area. Then, scanning exposure is performed on the second shot area. Similarly, the control device repeats stepping between shot areas on substrate P and scanning exposure on the shot areas to transfer the pattern of mask MSK to all shot areas on substrate P.

[0026] (Configuration of illumination system IOP) Next, the configuration of illumination system IOP in this embodiment will be described. Illumination system IOP includes a plurality of illumination units 90 corresponding to the plurality of projection optical units 100 included in projection optical system PL. Figure 2 is a diagram schematically showing the configuration of illumination unit 90.

[0027] The illumination unit 90 includes a first light source unit OPU1, a second light source unit OPU2, and an illumination optical system 80.

[0028] (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.

[0029] Fig. 3A is a plan view schematically illustrating the configuration of the first light source array 20A and the second light source array 20B, and Fig. 3B is a diagram schematically illustrating the internal configuration of the first light source unit OPU1 and the second light source unit OPU2.

[0030] As shown in Fig. 3A, the first light source array 20A includes a plurality of LED (Light Emitting Diode) chips 23A (5 x 5 in Fig. 3A) arranged two-dimensionally on a substrate 21A, for example. The number of LED chips 23A may be changed as needed. The LED chips 23A are arranged at a pitch P1, which is the distance between the centers of adjacent LED chips 23A.

[0031] Each of the multiple LED chips 23A has a light-emitting portion 231A, and the peak wavelength of the 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). It is more preferable that the peak wavelength of the 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. In the following description, the two directions in which the LED chips 23A are arranged are referred to 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 referred to 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.

[0032] The first magnifying optical system 30A is a magnifying optical system for forming a magnified image of the light-emitting portion 231A of each LED chip 23A on a predetermined plane PP. As shown in FIG. 3B, 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 lens unit 31A is a double-telecentric optical system that magnifies and projects the light-emitting portion 231A at a magnification M1 equal to or greater than (the arrangement pitch P1 of the LED chips 23A) / (the length a1 of one side of the light-emitting surface of the light-emitting portion 231A). Note that, for clarity of illustration, FIG. 3B shows only four LED chips 23A (23B) arranged in a row along the Y1 direction.

[0033] The second light source array 20B includes, for example, a plurality of LED chips 23B (5 x 5 in FIG. 3A) arranged two-dimensionally on a substrate 21B. The number of LED chips 23B may be changed as needed. The LED chips 23B are arranged at a pitch P2, which is the distance between the centers of adjacent LED chips 23B. 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.

[0034] Each of the multiple 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.

[0035] The second magnifying optical system 30B is an optical system for forming a magnified image of the light-emitting portion 231B of each LED chip 23B on a predetermined plane PP. As shown in FIG. 3B , the second magnifying optical system 30B includes a plurality of lens units 31B arranged to correspond to the arrangement of the LED chips 23B. Each of the lens units 31B is a double-telecentric optical system that magnifies and projects the light-emitting portion 231B at a magnification M2 that is equal to or greater than (the arrangement pitch P2 of the LED chips 23B) / (the length a2 of one side of the light-emitting surface of the light-emitting portion 231B).

[0036] In this embodiment, each of the lens units 31A and 31B includes four plano-convex lenses, but this is not limited to this, and the lens units 31A and 31B may include, for example, two biconvex lenses, three biconvex lenses, or a plano-convex lens and a biconvex lens.

[0037] Here, during the manufacturing process of the first light source array 20A and the second light source array 20B, when the LED chips 23A, 23B are arranged and fixed on the substrates 21A, 21B (more specifically, during cream solder reflow), the fixing positions of the LED chips 23A, 23B may be shifted from their designed positions. The positional shift of the LED chips 23A, 23B leads to a reduction in the illuminance of the light emitted from the first light source unit OPU1 and the second light source unit OPU2.

[0038] Therefore, in this embodiment, the substrates 21A and 21B are provided with protrusions 211, each consisting of a portion of the substrates 21A and 21B, which suppress misalignment of the LED chips 23A and 23B during manufacturing. Figures 4(A) and 4(B) are diagrams for explaining the protrusions 211 provided on the substrates 21A and 21B, with Figure 4(A) being a plan view of the substrates 21A and 21B, and Figure 4(B) being a cross-sectional view taken along line A-A in Figure 4(A). Since the protrusions 211 provided on the substrates 21A and 21B have the same structure, only the substrate 21A will be described here. For the sake of explanation, Figures 4(A) and 4(B) illustrate only a portion of the LED chip 23A. Furthermore, hatching of the LED chip 23A has been omitted in Figure 4(B).

[0039] The protrusions 211 are provided between the multiple LED chips 23A. In this embodiment, as shown in FIGS. 4A and 4B, the cross-shaped protrusions 211 are provided adjacent to the corners of each LED chip 23A. As shown in FIG. 4B, the end 211a of the protrusion 211 is located higher than the lower surface (the surface on the -Z1 side) of the LED chip 23A. The height of the protrusion 211 may be such that the end 211a is located higher than the lower surface of the LED chip 23A and does not block the light emitted from the LED chip 23A. The shape of the protrusion 211 may be such that the light emitted from the LED chip 23A does not enter the protrusion 211. The protrusions 211 and the LED chip 23A may be in contact with each other, or there may be a gap between the protrusion 211 and the LED chip 23A.

[0040] During manufacturing of the first light source array 20A, the LED chips 23A are arranged in an area defined by four adjacent protrusions 211 (an area surrounded by the four protrusions 211). Because the end 211a of the protrusion 211 is located higher than the lower surface of the LED chip 23A, movement of the LED chip 23A arranged in this area is restricted. Therefore, misalignment of the LED chip 23A is suppressed when the LED chip 23A is fixed to the substrate 21A. This suppresses a decrease in illuminance due to misalignment of the LED chip 23A, allowing the first light source unit OPU1 to emit high-brightness light.

[0041] (Configuration of illumination optical system 80) Returning to Figure 2, the illumination optical system 80 includes a first focusing optical system (first optical system) 81A including a first dichroic mirror DM1, a second focusing optical system (second optical system) 81B, a second dichroic mirror DM2, an imaging optical system 83, a fly's eye lens FEL, and a condenser optical system 84.

[0042] The first focusing optical system 81A forms a pupil of the magnified image of the light-emitting unit 231A formed by the first magnifying optical system 30A. That is, the rear focal position of the first focusing optical system 81A is the pupil position. The first focusing optical system 81A has a first dichroic mirror DM1 along the optical path, which reflects at least a portion of the light with a peak wavelength of 385 nm. This causes the light beam to be incident on the second dichroic mirror DM2. Note that the first focusing optical system 81A may be configured without the first dichroic mirror DM1. In this case, the arrangement of the first light source unit OPU1 and the arrangement of each lens in the first focusing optical system 81A may be appropriately adjusted so that the light beam is incident on the second dichroic mirror DM2. Furthermore, the first focusing optical system 81A may be configured with a single lens or a lens group including multiple lenses.

[0043] The second focusing optical system 81B forms a pupil of the magnified image of the light-emitting unit 231B formed by the second magnifying optical system 30B. That is, the rear focal position of the second focusing optical system 81B is the pupil position. The second focusing optical system 81B may be composed of a single lens or a lens group including multiple lenses.

[0044] The second dichroic mirror DM2 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, thereby forming a composite image 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.

[0045] In this embodiment, the second dichroic mirror DM2 forms a composite image 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. That is, the second dichroic mirror DM2 is disposed at a position that is the back focal position of the first focusing optical system 81A and the back focal position of the second focusing optical system 81B. As a result, the second dichroic mirror DM2 Koehler-illuminates the light emitted from the first light source unit OPU1 and the light emitted from the second light source unit OPU2. By Koehler-illuminating the light, it is possible to reduce changes in the illuminance of the light beam of the pupil image formed by the first focusing optical system 81A and the second focusing optical system 81B. In addition, without being limited to the configuration of this embodiment, 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 second dichroic mirror DM2, respectively.

[0046] The illumination unit 90 is provided with a detector DT10 for monitoring light with a peak wavelength of 385 nm, a detector DT20 for monitoring light with a peak wavelength of 365 nm, and a detector DT30 for monitoring light with a peak wavelength of 385 nm and light with a peak wavelength of 365 nm.

[0047] Specifically, detector DT10 detects the illuminance of light with a peak wavelength of 385 nm reflected by first dichroic mirror DM1. Detector DT20 detects the illuminance of light with a peak wavelength of 365 nm reflected by second dichroic mirror DM2. Detector DT30 detects the illuminance of 385 nm light unintentionally reflected by second dichroic mirror DM2 and the illuminance of 365 nm light unintentionally transmitted by second dichroic mirror DM2.

[0048] The detection results of detectors DT10 to DT30 are output to a control device not shown, and the control device controls the value of the current supplied to the LED chips 23A and 23B provided in the first light source unit OPU1 and the second light source unit OPU2, respectively, based on the detection results of detectors DT10 to DT30.

[0049] The imaging optical system 83 is a double-telecentric optical system that projects the composite image formed by the second dichroic mirror DM2 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 second dichroic mirror DM2 onto the incident end of the fly-eye lens FEL.

[0050] The fly-eye lens FEL is constructed by closely arranging a large number of lens elements, each having a positive refractive power, in a vertical and horizontal direction so that their optical axes are parallel to the reference optical axis AX. Each lens element 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 substrate P).

[0051] Therefore, the light beam incident on the fly-eye lens FEL is wavefront split by the multiple lens elements, and one light source image is formed on or near the rear focal plane (exit surface) of each lens element. That is, 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 (exit surface) of the fly-eye lens FEL. The light beam from the secondary light source formed on or near the rear focal plane (exit surface) of the fly-eye lens FEL is incident on an aperture stop 85 arranged nearby. Note that in this embodiment, the rear focal plane (exit surface) of the fly-eye lens FEL is optically conjugate with the first light source array 20A and the second light source array 20B.

[0052] 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.

[0053] 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 combination of the wavelengths of the light emitted by the first light source unit OPU1 and the second light source unit OPU2 is not limited to these examples. In addition, if the combination of the wavelength of the light emitted by the first light source unit OPU1 and the wavelength of the 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 mirror appropriately depending on the wavelength used.

[0054] (Method of Manufacturing Light Source Array) Next, a method of manufacturing the first light source array 20A and the second light source array 20B will be described. Since the first light source array 20A and the second light source array 20B are manufactured by the same method, only the first light source array 20A will be described here.

[0055] Figures 5(A) to 5(H) are diagrams showing a manufacturing method of the first light source array 20 A. Figure 5(B) is a cross-sectional view taken along line A-A in Figure 5(A), Figure 5(D) is a cross-sectional view taken along line B-B in Figure 5(C), Figure 5(F) is a cross-sectional view taken along line C-C in Figure 5(E), and Figure 5(H) is a cross-sectional view taken along line D-D in Figure 5(G).

[0056] First, as shown in Figures 5A and 5B, a substrate 21A is prepared. The substrate 21A is made of a metal such as copper (Cu).

[0057] 5(C) and 5(D), the substrate 21A is etched to form the posts 212 and the protrusions 211. As a result, the protrusions 211 are formed from a portion of the substrate 21A, which increases the strength of the protrusions 211. The etching is performed using, for example, a resist patterned by a photolithography process as a mask.

[0058] Next, as shown in FIGS. 5(E) and 5(F), an insulating layer 221 and a wiring layer 222 are sequentially formed on the substrate 21A. Next, as shown in FIGS. 5(G) and 5(H), cream solder 223 is applied to the upper surfaces of the posts 212 and the wiring layer 222, and the LED chips 23A are placed in the areas defined by the protrusions 211. The LED chips 23A are then fixed to the substrate 21A by reflow soldering. At this time, the protrusions 211 limit the movement of the LED chips 23A, thereby suppressing misalignment of the LED chips 23A. Through the above process, a first light source array 20A in which misalignment of the LED chips 23A is suppressed can be obtained. Note that, as shown in the drawings, in this embodiment, the LED chips 23A are connected in series in the X1 direction.

[0059] As described above in detail, according to this embodiment, the first light source unit OPU1 includes a plurality of LED chips 23A arranged two-dimensionally on the surface of the substrate 21A, and protrusions 211 that protrude from the substrate 21A and are provided between the plurality of LED chips 23A. The ends 211a of the protrusions 211 are positioned higher than the bottom surfaces of the LED chips 23A. As a result, when the LED chips 23A are fixed to the substrate 21A, the protrusions 211 restrict movement of the LED chips 23A, thereby preventing misalignment of the LED chips 23A, thereby preventing a decrease in illuminance of the first light source unit OPU1. Therefore, the first light source unit OPU1 can achieve a high-brightness surface light source.

[0060] Furthermore, according to this embodiment, the substrate 21A is made of a metal material, which makes it possible to easily form the protrusions 211 by etching or the like.

[0061] Furthermore, according to this embodiment, the protrusion 211 is made of a part of the substrate 21 A. This provides the protrusion 211 with high strength.

[0062] (Variation 1) In the above embodiment, the protrusions 211 are provided adjacent to the corners of the LED chips 23A, but this is not limiting. The protrusions 211 may be provided between each LED chip 23A and at least one of the other LED chips 23A adjacent to that LED chip 23A.

[0063] FIG. 6(A) is a plan view showing an example of a protrusion 211A according to Modification 1, and FIG. 6(B) is a cross-sectional view taken along line A-A in FIG. 6(A). As shown in FIGS. 6(A) and 6(B), the protrusion 211A according to Modification 1 is cylindrical. In Modification 1, when LED chips 23A arranged in 2 rows by 2 rows in the X1 and Y1 directions constitute one set (indicated by the two-dot chain line), the protrusions 211A are provided between adjacent LED chips 23A in the X1 direction and between adjacent LED chips 23A in the Y1 direction within one set. Furthermore, no protrusions 211A are provided between adjacent sets in the X1 and Y1 directions, but protrusions 211A may be provided between adjacent sets. The protrusions 211A and the LED chips 23A may be in contact with each other, or there may be a gap between the protrusions 211A and the LED chips 23A.

[0064] When the substrate 21A has such a protrusion 211A, during manufacturing of the first light source array 20A, the LED chips 23A can be pressed against the protrusion 211A using a jig or the like and reflowed, thereby preventing misalignment of the LED chips 23A. Note that the substrate 21A may be provided with a mechanism for pressing the LED chips 23A against the protrusion 211A.

[0065] When the cylindrical protrusion 211A is used as in the first modification, the LED chip 23A and the protrusion 211A come into contact with each other at a point, thereby improving the positioning accuracy of the LED chip 23A.

[0066] For example, within one set, a cross-shaped protrusion 211 may be placed in the center, and cylindrical protrusions 211A may be placed between adjacent LED chips 23A in the X1 direction and between adjacent LED chips 23A in the Y1 direction.

[0067] (Variation 2) FIG. 7(A) is a plan view showing an example of a protrusion 211B according to Variation 2, and FIG. 7(B) is a cross-sectional view taken along line A-A in FIG. 7(A). As shown in FIGS. 7(A) and 7(B), in Variation 2, within one set indicated by the two-dot chain line, wall-shaped protrusions 211B are provided between adjacent LED chips 23A in the X1 direction and between adjacent LED chips 23A in the Y1 direction. In this case, as in Variation 1, the LED chip 23A is pressed against the protrusions 211B for reflow soldering, thereby preventing misalignment of the LED chip 23A. The protrusions 211B and the LED chip 23A may be in contact with each other, or there may be a gap between the protrusions 211B and the LED chip 23A. Although no protrusions 211B are provided between adjacent sets in the X1 and Y1 directions in Variation 2, protrusions 211B may be provided between adjacent sets.

[0068] The wall-like protrusions 211B may be provided adjacent to each side of the LED chip 23A. In this case, by disposing the LED chip 23A in the area surrounded by the wall-like protrusions 211B, it is possible to prevent the LED chip 23A from being misaligned.

[0069] (Variation 3) In the above embodiment and variations 1 and 2, the protrusions 211, 211A, and 211B are adjacent to, for example, a portion of the side of the LED chip 23A. However, the protrusion 211 may be formed to surround the entire periphery of the LED chip 23A. FIG. 8(A) is a plan view showing an example of a protrusion 211C according to Variation 3, and FIG. 8(B) is a cross-sectional view taken along line A-A in FIG. 8(A). In Variation 3, the protrusion 211C is realized by forming a recess 213 in the substrate 21A that accommodates the LED chip 23A. As a result, the protrusion 211C surrounds the entire periphery of the LED chip 23A. By accommodating the LED chip 23A in the recess 213, it is possible to prevent the LED chip 23A from becoming misaligned.

[0070] In the above embodiment and modified examples 1 to 3, the protrusions 211, 211A, 211B, and 211C are described as being part of the substrate 21A, but this is not limiting. For example, in the embodiment and modified examples 1 and 2, the protrusions 211, 211A, and 211B may be members that come into contact with the substrate 21A but are different from the substrate 21A (members separate from the substrate 21A). In other words, the protrusions 211, 211A, and 211B may be formed by fixing (soldering or adhering) a member different from the substrate 21A to the substrate 21A. In this case, the protrusions 211, 211A, and 211B may be formed from the same material as the substrate 21A, or from a different material.

[0071] Furthermore, in the above embodiment and Modifications 1 to 3, the LED chips 23A are arranged on the substrate 21A, but this is not limiting. The LED chips 23A may be arranged on a heat sink. The same applies to the LED chips 23B. Examples of heat sinks include a microchannel heat sink having a flow path therein for refrigerant to flow through, and a fin-type heat sink. The amount of light emitted from an LED decreases as the temperature of the LED chip 23A increases, but by arranging the LED chip 23A on a heat sink, it is possible to suppress the temperature increase of the LED chip 23A.

[0072] Furthermore, in the above embodiment and Modifications 1 to 3, the illumination unit 90 includes the first light source unit OPU1, the second light source unit OPU2, and the illumination optical system 80 including the second dichroic mirror DM2, but this is not limited to this. For example, the illumination unit 90 may include only one of the first light source unit OPU1 and the second light source unit OPU2. In this case, the illumination optical system 80 may have any configuration as long as it can guide light emitted from the first light source unit OPU1 or the second light source unit OPU2 to the mask MSK.

[0073] 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.

[0074] 10 Exposure device 20A First light source array 20B Second light source array 21A, 21B Substrate 23A, 23B LED chip 31A, 31B Lens section 80 Illumination optical system 90 Illumination unit 100 Projection optical unit 211, 211A, 211B, 211C Protrusion 211a End 231A, 231B Light-emitting section DM2 Second dichroic mirror MSK Mask OPU1 First light source unit OPU2 Second light source unit P Substrate

Claims

1. A plurality of light source elements two-dimensionally arranged on the surface of an object to be fixed, A protruding portion protruding from the object to be fixed, Comprising, The end of the protruding portion is at a position higher than the lower surface of each light source element of the plurality of light source elements, The protruding portion is provided on both sides in the first direction of each light source element of the plurality of light source elements and on both sides in the second direction intersecting the first direction, Light source unit.

2. The object to be fixed is a substrate or a heat sink, The light source unit according to claim 1.

3. The heat sink has a flow path through which a refrigerant passes inside, The light source unit according to claim 2.

4. The object to be fixed is formed of a metal material, The light source unit according to any one of claims 1 to 3.

5. The protruding portion is part of the object to be fixed, The light source unit according to any one of claims 1 to 3.

6. The protruding portion is in contact with the object to be fixed and is made of a member different from the object to be fixed, The light source unit according to any one of claims 1 to 3.

7. The light emitted from the plurality of light source elements does not enter the protruding portion, The light source unit according to any one of claims 1 to 3.

8. The protruding portion is cross-shaped and is provided so as to be adjacent to the corner portions of each light source element of the plurality of light source elements, The light source unit according to any one of claims 1 to 3.

9. Each of the plurality of light source elements includes a light emitting portion that emits light, The light source unit further includes a lens array in which a plurality of lens portions that form an enlarged image of the light emitting portion of each of the plurality of light source elements are arranged on a two-dimensional plane, The light source unit according to any one of claims 1 to 3.

10. The light source element is a light emitting diode element, The light source unit according to any one of claims 1 to 3.

11. The light source element emits light having a peak wavelength in the range of 360 to 440 nm, The light source unit according to any one of claims 1 to 3.

12. The light source unit according to claim 1, An illumination optical system that guides the light emitted from the light source unit to an object to be irradiated, An illumination unit comprising.

13. A plurality of light source units according to claim 1, An illumination optical system that includes a combining optical element that combines the light emitted from the plurality of light source units and guides the combined light emitted from the combining optical element to an object to be irradiated, An illumination unit comprising.

14. The lighting unit according to claim 12 or claim 13, and a projection optical system that projects a pattern image of a mask illuminated by the lighting unit onto a photosensitive substrate, An exposure apparatus comprising:

15. The photosensitive substrate has a length or diagonal length of at least one side of 500 mm or more, The exposure apparatus according to claim 14.

16. An exposure method using the exposure apparatus according to claim 14, comprising: Illuminating a mask with the lighting unit; and Projecting a pattern image of the mask onto a photosensitive substrate using the projection optical system. An exposure method comprising: