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

Abstract

The purpose is to improve the closeness between the substrate and the heat sink by suppressing the warping or bending of the substrate on which the light source elements are arranged, thereby improving the cooling efficiency. The light source unit comprises: a substrate (21A) having a first surface and a second surface opposite to each other; a plurality of light source elements (20A) arranged in two dimensions on the first surface of the substrate (21A); and a heat sink (40), wherein the substrate (21A) has at least one recessed portion formed in a portion of the second surface opposite to the range on which the plurality of light source elements (20A) are arranged in a plan view, and the heat sink (40) has a through hole (401), and the substrate (21A) and the heat sink (40) are fixed by a fixing member (61) inserted through the through hole (401) and engaged with the recessed portion.

Description

Technical Field

[0001] The invention relates to a light source unit, an illumination unit, an exposure device, and an exposure method. Background Art

[0002] In recent years, liquid crystal display panels have been widely used as display elements for personal computers, televisions, etc. Liquid crystal display panels are manufactured by forming a circuit pattern of a thin film transistor on a plate (glass substrate) using a photolithography technique. As a device used in the photolithography process, an exposure device is used that projects and exposes the original pattern formed on the photomask onto the photoresist layer on the plate via a projection optical system.

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

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2006-201476 Summary of the invention

[0007] According to the first disclosed aspect, the light source unit comprises: a substrate having a first surface and a second surface opposite to each other; a plurality of light source elements arranged in two dimensions on the first surface of the substrate; and a heat sink, the substrate having at least one recessed portion formed in a portion of the second surface opposite to a range in which the plurality of light source elements are arranged when viewed from above, the heat sink having a through hole, and the substrate and the heat sink being fixed by means of a fixing member inserted through the through hole and engaged with the recessed portion.

[0008] According to a second disclosed aspect, a lighting unit includes: the above-described light source unit; and an illumination optical system that guides light emitted from the light source unit to an illuminated object.

[0009] According to the third disclosed aspect, the lighting unit comprises: a plurality of the above-mentioned light source units; and an illumination optical system including a synthesis optical element for synthesizing light emitted from the plurality of the light source units, and guiding the synthesized light emitted from the synthesis optical element to an illuminated object.

[0010] According to a fourth disclosed aspect, an exposure apparatus includes: the lighting unit described above; and a projection optical system that projects a pattern image of a photomask illuminated by the lighting unit onto a photosensitive substrate.

[0011] According to a fifth disclosed aspect, an exposure method is an exposure method using the above-mentioned exposure device, comprising: illuminating a photomask using the lighting unit; and projecting a pattern image of the photomask onto a photosensitive substrate using the projection optical system.

[0012] It should be noted that the configuration of the embodiments described below may be appropriately improved, and at least a portion may be replaced by other components. Moreover, the technical features that are not particularly limited in their configuration are not limited to the configuration disclosed in the embodiments, and can be configured at a position that can achieve their functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram showing the structure of an exposure apparatus according to an embodiment.

[0014] Figure 2 This is a schematic diagram showing the structure of the lighting unit.

[0015] Figure 3 (A) is a front view of the first and second light source arrays, Figure 3 (B) is Figure 3 (A) AA line cross-sectional view.

[0016] Figure 4 This is a back view of the substrate.

[0017] Figure 5 It is a perspective view showing a heat sink and a first light source array.

[0018] Figure 6 It is a perspective view showing the surface on the -Z1 side of the heat sink.

[0019] Figure 7 (A) is a front view showing a heat sink and a first light source array, Figure 7 (B) is Figure 7 (A) AA line cross-sectional view.

[0020] Figure 8 It is a diagram for explaining the first and second magnifying optical systems.

[0021] Fig. 9 (A) is a front view showing a heat sink and a light source array of a comparative example, Fig. 9 (B) is Fig. 9 (A) AA line cross-sectional view.

[0022] Fig.10 It is a graph showing the measurement results of the surface temperature of the substrate.

[0023] Fig.11 It is a cross-sectional view for explaining a modified example. DETAILED DESCRIPTION

[0024] based on Figures 1 to 8 , an exposure device 10 according to one embodiment is described.

[0025] (Configuration of Exposure Apparatus)

[0026] First, use Figure 1 The configuration of exposure apparatus 10 according to one embodiment will be described. Figure 1 This is a diagram schematically showing the configuration of an exposure device 10 according to one embodiment.

[0027] The exposure device 10 is a scanning stepper (scanner) that drives the mask MSK and the glass substrate (hereinafter referred to as "plate") P in the same direction and at the same speed relative to the projection optical system PL, thereby transferring the pattern formed on the mask MSK to the plate P. The plate P is, for example, a rectangular glass substrate used in a liquid crystal display device (flat panel display), and the length of at least one side or the diagonal length is 500 mm or more.

[0028] Below, the direction in which the mask MSK and the plate P are driven during scanning exposure (scanning direction) is set as the X-axis direction, the direction in the horizontal plane perpendicular to it is set as the Y-axis direction, the direction perpendicular to the X-axis and the Y-axis is set as the Z-axis direction, and the rotation (tilt) directions around the X-axis, Y-axis, and Z-axis are set as θx, θy, and θz directions, respectively.

[0029] The exposure device 10 includes an illumination system IOP, a mask stage MST holding a mask MSK, a projection optical system PL, a main body 70 supporting these components, a substrate stage PST holding a plate P, and control systems for these components. The control system collectively controls the components of the exposure device 10 .

[0030] The main body 70 includes a base (vibration-proof table) 71, columns 72A and 72B, an optical fixing plate 73, a support body 74, and a sliding guide 75. The base (vibration-proof table) 71 is arranged on the ground F, and supports the columns 72A and 72B and the like while isolating vibration from the ground F. The columns 72A and 72B each have a frame shape, and the column 72A is arranged inside the column 72B. The optical fixing plate 73 has a flat plate shape and is fixed to the top of the column 72A. The support body 74 is supported on the top of the column 72B via the sliding guide 75. The sliding guide 75 has a balloon lifter and a positioning mechanism, and positions the support body 74 (i.e., the mask stage MST described later) at an appropriate position in the X-axis direction relative to the optical fixing plate 73.

[0031] The illumination system IOP is arranged above the main 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.

[0032] The mask stage MST is supported by a support body 74. It has a pattern surface ( Figure 1The mask MSK (the lower surface of the optical system) is fixed to the mask stage MST by, for example, vacuum adsorption (or electrostatic adsorption). The mask stage MST is driven by a drive system including, for example, a linear motor with a predetermined stroke in the scanning direction (X-axis direction) and is slightly driven in the non-scanning direction (Y-axis direction and θz direction).

[0033] The position information of the mask stage MST in the XY plane (including the rotation information in the θz direction) is measured by the interferometer system. The interferometer system irradiates the moving mirror (or the reflective surface (not shown) obtained by mirror processing) provided at the end of the mask stage MST with a length measurement beam, receives the reflected light from the moving mirror, and thereby measures the position of the mask stage MST. The measurement result is supplied to the control device (not shown), and the control device drives the mask stage MST with the help of the drive system according to the measurement result of the interferometer system.

[0034] The projection optical system PL is supported on the optical fixing plate 73 below the mask stage MST (-Z side). The projection optical system PL is configured similarly to the projection optical system disclosed in, for example, the specification of U.S. Patent No. 5,729,331, and includes a projection area of ​​the pattern image of the mask MSK, for example, a plurality of (for example, 7) projection optical units 100 (multi-lens projection optical units) arranged in a staggered manner, forming an image field in a rectangular shape with the Y-axis direction as the long side direction. Here, four projection optical units 100 are arranged at a predetermined interval in the Y-axis direction, and the remaining three projection optical units 100 are separated from the four projection optical units 100 to the +X side and arranged at a predetermined interval in the Y-axis direction. As each of the plurality of projection optical units 100, a unit that forms an erect image using, for example, a double telecentric equal magnification system is used. It should be noted that the plurality of projection areas of the projection optical units 100 arranged in a staggered manner are collectively referred to as exposure areas.

[0035] 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 projection image (partial erect image) of the circuit pattern of the mask MSK in the illumination area on the plate P arranged on the image plane side of the projection optical system PL using the illumination light IL. Here, a resist (sensitizer) is applied on the surface of the plate P. The mask stage MST and the substrate stage PST are synchronously driven, that is, the mask MSK is driven in the scanning direction (X-axis direction) relative to the illumination area (illumination light IL), and the plate P is driven in the same scanning direction relative to the exposure area (illumination light IL), thereby exposing the plate P and transferring the pattern of the mask MSK onto the plate P.

[0036] The substrate stage PST is disposed on a base (anti-vibration table) 71 below (at the −Z side) the projection optical system PL. The plate P is held on the substrate stage PST via a substrate holder (not shown).

[0037] The position information of the substrate stage PST in the XY plane (including rotation information (deflection amount (rotation amount θz in the θz direction), pitch amount (rotation amount θx in the θx direction), roll amount (rotation amount θy in the θy direction))) is measured by the interferometer system. The interferometer system irradiates a length measurement beam from the optical fixing plate 73 to a movable mirror (or a reflective surface obtained by mirror processing (not shown)) provided at the end of the substrate stage PST, receives reflected light from the movable mirror, and thereby measures the position of the substrate stage PST. The measurement results are supplied to a control device (not shown), and the control device drives the substrate stage PST according to the measurement results of the interferometer system.

[0038] In the exposure device 10, alignment measurement (for example, EGA, etc.) is performed before exposure, and the plate P is exposed according to the following steps using the result. First, according to the instruction of the control device, the mask stage MST and the substrate stage PST are synchronously driven along the X-axis direction. Thus, scanning exposure to the first shooting area on the plate P is performed. If the scanning exposure relative to the first shooting area is completed, the control device moves (steps) the substrate stage PST to a position corresponding to the second shooting area. Then, scanning exposure relative to the second shooting area is performed. The control device repeats the stepping between the shooting areas of the plate P and the scanning exposure relative to the shooting areas in the same way, and transfers the pattern of the mask MSK to all the shooting areas on the plate P.

[0039] (Composition of the lighting system IOP)

[0040] Next, the configuration of the illumination system IOP in the present embodiment will be described. The illumination system IOP includes a plurality of illumination units 90 corresponding to the plurality of projection optical units 100 included in the projection optical system PL. Figure 2 It is a diagram schematically showing the structure of the lighting unit 90.

[0041] The illumination unit 90 includes a first light source unit OPU1 , a second light source unit OPU2 , and an illumination optical system 80 .

[0042] (Configuration of light source unit)

[0043] The first light source unit OPU1 includes a heat sink 40, a first light source array 20A, and a first magnifying optical system 30A, and the second light source unit OPU2 includes a heat sink 40, a second light source array 20B, and a second magnifying optical system 30B.

[0044] Figure 3(A) is a front view schematically showing the configuration of the first light source array 20A and the second light source array 20B. Figure 3 (B) is Figure 3 It should be noted that in Figure 3 In (B), hatching of LED chips 23A and 23B described later is omitted.

[0045] like Figure 3 As shown in (A), the first light source array 20A has a substrate 21A, a plurality of light sources (in Figure 3 In (A), 5×5) LED (Light Emitting Diode) chips 23A. The number of LED chips 23A may be changed as needed.

[0046] The substrate 21A has a first surface 21a and a second surface 21b facing each other, and LED chips 23A are arranged on the first surface 21a. The LED chips 23A are arranged at a pitch P1, which is the distance between the centers of adjacent LED chips 23A.

[0047] The plurality of LED chips 23A respectively have a light-emitting portion 231A, and the peak wavelength of the light emitted from the light-emitting portion 231A is within the range of 380 to 390 nm. That is, the light-emitting portion 231A is an ultraviolet LED (UV LED). The peak wavelength of the light emitted from the light-emitting portion 231A is more preferably 385 nm. The light-emitting surface of the light-emitting portion 231A is a square, and the length of one side thereof is a1. It should be noted that in the following description, the two directions in which the LED chips 23A are arranged are set as the X1 direction and the Y1 direction. The X1 direction and the Y1 direction are orthogonal. In addition, the direction orthogonal to the X1 direction and the Y1 direction is set as the Z1 direction. The Z1 direction is roughly parallel to the optical axis of the light emitted from the light-emitting portion 231A.

[0048] The second light source array 20B includes a substrate 21B and a plurality of light sources (in Figure 3 (A) (5×5) LED chips 23B. The number of LED chips 23B can be appropriately changed as needed. The substrate 21B also has a first surface 21a and a second surface 21b that are opposite to each other, and the LED chips 23B are arranged on the first surface 21a. The LED chips 23B are arranged at a pitch P2, and the pitch P2 is the distance between the centers of adjacent LED chips 23B. The arrangement pitch P1 of the LED chip 23A and the arrangement pitch P2 of the LED chip 23B can be the same or different.

[0049] 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 within the range of 360 to 370 nm. That is, the light emitting portion 231B is a UVLED. The peak wavelength of the light emitted from the light emitting portion 231B is more preferably 365 nm. The light emitting surface of the light emitting portion 231B is a square, and the length of one side is a2. The length a2 of one side of the light emitting surface of the light emitting portion 231B may be the same as or different from the length a1 of one side of the light emitting surface of the light emitting portion 231A.

[0050] Figure 4 21A and 21B are metal substrates with a thickness of less than 5 mm. The substrates 21A and 21B are preferably made of a highly thermally conductive material, for example, a copper substrate. Figure 3 (B) and Figure 4 As shown, a plurality of recesses 211 are formed in a portion AR1 of the second surface 21b of the substrate 21A, 21B opposite to the first surface 21a, which is opposite to the range where the plurality of LED chips 23A, 23B are arranged in a plan view. Figure 4 In the present embodiment, the plurality of recesses 211 are provided at equal intervals in the X1 direction and the Y1 direction.

[0051] like Figure 3 As shown in (B), the recessed portion 211 does not penetrate the substrates 21A and 21B. In this embodiment, the recessed portion 211 is a threaded hole, which will be described in detail later. By engaging the recessed portion 211 with the bolt 61, the substrates 21A and 21B can be fixed to the heat sink 40.

[0052] Figure 5 is a perspective view showing the heat sink 40 and the first light source array 20A. Figure 6 : is a perspective view showing the surface on the -Z1 side of the heat sink 40. Figure 7 (A) is a front view showing the heat sink 40 and the first light source array 20A. Figure 7 (B) is Figure 7 The relationship between the second light source array 20B and the heat sink 40 is the same as that between the first light source array 20A and the heat sink 40. Therefore, the heat sink 40 and the first light source array 20A are described below. Figure 5 In FIG. 1 , as an example, the first light source array 20A is shown to have 10×14 LED chips 23A. Figure 7 In (B), the hatching of the LED chip 23A is omitted.

[0053] For example Figure 5 as well as Figure 7As shown in (A), in this embodiment, three first light source arrays 20A are arranged on the heat sink 40. It should be noted that the number of the first light source arrays 20A arranged on the heat sink 40 is not limited to three, and can be less than 2 or more than 4. That is, as long as at least one first light source array 20A is arranged on the heat sink 40, it will suffice.

[0054] like Figure 6 As shown, the heat sink 40 has a flow path 402 for circulating a refrigerant inside, a supply port 41 for supplying the refrigerant to the flow path 402, and a discharge port 42 for discharging the refrigerant passing through the flow path 402, so as to cool the LED chip 23A of the first light source array 20A. The refrigerant can be a liquid or a gas, but is preferably water. If the temperature of the LED chip 23A rises, the brightness of the light from the light-emitting portion 231A of the LED chip 23A decreases. In other words, if the temperature rises, the luminous efficiency of the LED chip 23A decreases. By cooling the LED chip 23A using the heat sink 40, the decrease in the brightness of the light emitted from the first light source array 20A can be suppressed.

[0055] In addition, the heat sink 40 is Figure 6 as well as Figure 7 As shown in (B), there is a through hole 401 penetrating the heat sink 40. The diameter of the through hole 401 is a stepped through hole that changes in two stages. The flow path 402 inside the heat sink 40 is formed in a portion where the through hole 401 is not formed. In addition, the through hole 401 is provided at a position corresponding to the recessed portion 211 provided on the second surface 21b of the substrate 21A of the first light source array 20A.

[0056] like Figure 7 As shown in (B), a heat-conducting member 50 such as a thermal interface material (TIM) is provided between the substrate 21A and the heat sink 40. In the present embodiment, a heat-conducting sheet is used as the heat-conducting member 50. The heat-conducting member 50 may be a heat-conducting grease or the like. The heat-conducting member 50 is provided to contact a portion AR1 corresponding to a range where at least the LED chips 23A are arranged in the second surface 21b of the substrate 21A. Thus, the small gap or unevenness between the substrate 21A and the heat sink 40 is filled, and the LED chips 23A can be efficiently cooled by the heat sink 40.

[0057] The heat sink 40 and the substrate 21A are inserted through the through hole 401 and fixed by a bolt 61 that engages (fits) with the recess 211. The bolt 61 penetrates the heat-conducting member 50. The length of the bolt 61 is set to a length that penetrates the heat-conducting member 50, and the heat sink 40 and the heat-conducting member 50, as well as the substrate 21A and the heat-conducting member 50, are respectively tightly fitted. Thus, the LED chip 23A can be efficiently cooled by the heat sink 40. It should be noted that in the present embodiment, the heat-conducting member 50 is provided corresponding to each first light source array 20A, but, for example, a sheet-like heat-conducting member 50 may also be provided relative to the three first light source arrays 20A.

[0058] Next, the first enlarging optical system 30A and the second enlarging optical system 30B will be described. Figure 8 It is a figure for demonstrating the 1st magnifying optical system 30A and the 2nd magnifying optical system 30B which the 1st light source unit OPU1 and the 2nd light source unit OPU2 have, respectively.

[0059] like Figure 8 As shown, the first magnifying optical system 30A is a magnifying optical system for forming magnified images of the light-emitting portion 231A of each LED chip 23A on a predetermined surface PP. The first magnifying optical system 30A has a plurality of lens portions 31A arranged in a manner corresponding to the arrangement of the LED chips 23A. The lens portions 31A are double telecentric optical systems that magnify and project the light-emitting portion 231A at a magnification M1 greater than (the arrangement pitch P1 of the LED chips 23B) / (the length a1 of one side of the light-emitting surface of the light-emitting portion 231A). It should be noted that in Figure 8 In order to make the drawing clearer, only four LED chips 23A (23B) arranged in one row along the Y1 direction are shown.

[0060] The second magnifying optical system 30B is a magnifying optical system for forming magnified images of the light emitting portion 231B of each LED chip 23B on a predetermined surface PP. The second magnifying optical system 30B has a plurality of lens portions 31B arranged in a manner corresponding to the arrangement of the LED chips 23B. The lens portions 31B are double telecentric optical systems that magnify and project the light emitting portion 231B at a magnification M2 greater than or equal to (the arrangement pitch P2 of the LED chips 23A) / (the length a2 of one side of the light emitting surface of the light emitting portion 231B).

[0061] In this embodiment, the lens portions 31A and 31B each have four plano-convex lenses, but the present invention is not limited thereto, and the lens portions 31A and 31B may have, for example, two biconvex lenses or three biconvex lenses. In addition, the lens portions 31A and 31B may also have, for example, plano-convex lenses and biconvex lenses.

[0062] (Configuration of Illumination Optical System 80)

[0063] return Figure 2 The illumination optical system 80 includes a first light collecting optical system (first optical system) 81A including a first dichroic mirror DM1, a second light collecting optical system (second optical system) 81B, a second dichroic mirror DM2, an imaging optical system 83, a fly-eye lens FEL, and a capacitance optical system 84.

[0064] The first light-collecting optical system 81A forms a pupil of the magnified image of the light-emitting portion 231A formed by the first magnifying optical system 30A. That is, the rear focal position of the first light-collecting optical system 81A becomes the position of the pupil. The first light-collecting optical system 81A has a first dichroic mirror DM1 in the middle of the optical path, which reflects at least a portion of the light with a peak wavelength of 385 nm. Thus, the light beam is incident on the second dichroic mirror DM2. It should be noted that the first light-collecting optical system 81A can be a structure without the first dichroic mirror DM1. In this case, it is sufficient to appropriately adjust the configuration of the first light source unit OPU1 and the configuration of each lens of the first light-collecting optical system 81A so that the light beam is incident on the second dichroic mirror DM2. In addition, the first light-collecting optical system 81A can be composed of one lens, or a lens group including a plurality of lenses.

[0065] The second light collecting optical system 81B forms a pupil of the magnified image of the light emitting unit 231B formed by the second enlarging optical system 30B. That is, the rear focus position of the second light collecting optical system 81B becomes the position of the pupil. The second light collecting optical system 81B may be formed by a single lens or a lens group including a plurality of lenses.

[0066] 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 in which the pupil image formed by the first light collecting optical system 81A and the pupil image formed by the second light collecting optical system 81B overlap.

[0067] In the present embodiment, the second dichroic mirror DM2 makes the pupil image formed by the first light-collecting optical system 81A overlap with the pupil image formed by the second light-collecting optical system 81B to form a composite image. That is, the second dichroic mirror DM2 is arranged at the following position, that is, arranged at the rear focal position of the first light-collecting optical system 81A and arranged at the rear focal position of the second light-collecting optical system 81B. Thus, the second dichroic mirror DM2 performs Kohler illumination on the light emitted from the first light source unit OPU1 and the light emitted from the second light source unit OPU2. By performing Kohler illumination, the illumination change of the light beam of the pupil image formed by the first light-collecting optical system 81A and the illumination change of the light beam of the pupil image formed by the second light-collecting optical system 81B can be reduced. It should be noted that, without being limited to the configuration of the present embodiment, the first light-collecting optical system 81A and the second light-collecting optical system 81B can also be configured to perform critical illumination to form the image of the first light source unit OPU1 and the image of the second light source unit OPU2 in the second dichroic mirror DM2, respectively.

[0068] The lighting unit 90 is provided with a detector DT10 for monitoring light having a peak wavelength of 385 nm, a detector DT20 for monitoring light having a peak wavelength of 365 nm, and a detector DT30 for monitoring light having a peak wavelength of 385 nm and light having a peak wavelength of 365 nm.

[0069] Specifically, the detector DT10 detects the illuminance of the light with a peak wavelength of 385 nm reflected by the first dichroic mirror DM1. The detector DT20 detects the illuminance of the light with a peak wavelength of 365 nm reflected by the second dichroic mirror DM2. The detector DT30 detects the illuminance of the light with a peak wavelength of 385 nm unintentionally reflected by the second dichroic mirror DM2 and the illuminance of the light with a peak wavelength of 365 nm unintentionally transmitted by the second dichroic mirror DM2.

[0070] The detection results of the 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 respectively possessed by the first light source unit OPU1 and the second light source unit OPU2 based on the detection results of the detectors DT10 to DT30.

[0071] The imaging optical system 83 is a double telecentric optical system that projects the composite image synthesized by the second dichroic mirror DM2 to the incident end of the fly-eye lens FEL at the same magnification. It should be noted that the imaging optical system 83 can also reduce the composite image synthesized by the second dichroic mirror DM2 and project it to the incident end of the fly-eye lens FEL.

[0072] The fly-eye lens FEL is constructed by, for example, arranging a plurality of lens elements having positive refractive power vertically and horizontally and densely in such a manner that the optical axes thereof 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 (the shape of the exposure area to be finally formed on the plate P).

[0073] Therefore, the light beam incident on the fly-eye lens FEL is divided by the wavefronts of multiple lens elements, and a light source image is formed on the rear focal plane (exit plane) of each lens element or in the vicinity thereof. That is, a substantial surface light source composed of multiple light source images, that is, a secondary light source, is formed on the rear focal plane (exit plane) of the fly-eye lens FEL or in the vicinity thereof. The light beam from the secondary light source formed on the rear focal plane (exit plane) of the fly-eye lens FEL or in the vicinity thereof is incident on the opening aperture 85 arranged in the vicinity thereof. It should be noted that in the present embodiment, the rear focal plane (exit plane) of the fly-eye lens FEL, the first light source array 20A, and the second light source array 20B are optically conjugate.

[0074] The aperture stop 85 is arranged at a position that is almost optically conjugate with the incident pupil plane of the projection optical system PL, and has a variable aperture portion for defining a range that contributes to the illumination of the secondary light source. Then, the aperture stop 85 sets the σ value (the ratio of the aperture of the secondary light source image on the pupil plane of the projection optical system to the aperture of the pupil plane) that determines the illumination condition to a desired value by changing the aperture of the variable aperture portion. The light from the secondary light source that has passed through the aperture stop 85, after receiving the light collecting action of the capacitor optical system 84, overlaps and illuminates the mask MSK formed with a prescribed pattern.

[0075] It should be noted that the wavelengths of the light emitted by the first light source unit OPU1 and the second light source unit OPU2 are not limited to the above-mentioned wavelengths, and the first light source unit OPU1 and the second light source unit OPU2 may be appropriately combined with LED chips that emit light having a peak wavelength in the range of 360 to 440 nm. For example, it may be configured so that the first light source unit OPU1 emits light having a peak wavelength of 405 nm, and the second light source unit OPU2 emits light having a peak wavelength of 385 nm. In addition, it may be configured so that the first light source unit OPU1 emits light having a peak wavelength of 395 nm, and the second light source unit OPU2 emits light having a peak wavelength of 385 nm. The combination of the wavelength of the light emitted from the first light source unit OPU1 and the wavelength of the light emitted from the second light source unit OPU2 is not limited to these examples. It should be noted that when the combination of the wavelength of the light emitted from the first light source unit OPU1 and the wavelength of the light emitted from the second light source unit OPU2 is set to a combination other than the first embodiment, it is preferred to appropriately change the material of the dichroic mirror according to the wavelength used.

[0076] (experiment)

[0077] The temperature of the substrate was obtained when the heat sink and the substrate were fixed by the method of the embodiment and when the heat sink and the substrate were fixed by the method of the comparative example. Here, the number of LED chips arranged in the light source array is 5×5.

[0078] (Comparative Example)

[0079] First, a method of fixing the heat sink 1040 and the substrate 1021 according to a comparative example will be described. Fig. 9 (A) is a front view showing a heat sink 1040 and a light source array 1020 of a comparative example, Fig. 9 (B) is Fig. 9 (A) AA line cross-sectional view.

[0080] like Fig. 9 As shown in (A), in the comparative example, three light source arrays 1020 are also arranged on the heat sink 1040. Each light source array 1020 has a substrate 1021 and a plurality of LED chips 23A. The number of LED chips 23A provided on the substrate 1021 and the arrangement pitch are the same as those of the first light source array 20A.

[0081] like Fig. 9 As shown in FIG. 1 (B), the heat sink 1040 of the comparative example includes a through hole 1401 and a fixing block 45. The fixing block 45 is fixed to the heat sink 1040 by a bolt 46. In addition, a threaded hole is formed at the end of the fixing block 45 on the +Z1 side.

[0082] The substrate 1021 is provided with through holes at four locations outside the range where the plurality of LED chips 23A are arranged. Bolts 60 are inserted into the through holes from the +Z1 side and engage with threaded holes formed at the end of the +Z1 side of the fixing block 45, thereby fixing the substrate 1021 to the heat sink 1040. The other configurations are the same as those in the embodiment, and therefore, detailed descriptions are omitted.

[0083] like Fig. 9 As shown in (A), the thermistor 25 is arranged on the surface of the substrate 1021, and the surface temperature of the substrate 1021 is measured. Similarly, the thermistor 25 is arranged on the surface of the substrate 21A and the surface temperature is measured. The thermistor 25 is arranged at the same position in the substrate 21A and the substrate 1021. Fig.10 is a graph showing the measurement results.

[0084] Fig.10 The horizontal axis shows each substrate, “left” shows the substrate arranged on the -Y1 side, “center” shows the substrate arranged on the center, “right” shows the substrate arranged on the +Y1 side, and “average” shows the average value of all substrates. Fig.10The vertical axis shows the temperature obtained from the measurement value of the thermistor 25 .

[0085] like Fig.10 As shown, it was confirmed that in any substrate, the heat sink 40 and the substrate 21A were fixed by the method of the embodiment, thereby the surface temperature of the substrate decreased compared with the method of the comparative example. That is, it was confirmed that the cooling effect of the LED chip 23A by the fixing method of the embodiment was higher than that of the fixing method of the comparative example. This is considered to be due to the following reasons. In the fixing method of the comparative example, the substrate 1021 was fixed to the heat sink 1040 at 4 locations outside the range where the plurality of LED chips 23A were arranged. Therefore, due to the warping and bending of the substrate 1021, the closeness between the heat conduction member 50, the substrate 1021, and the heat sink 1040 in the range where the LED chips 23A were arranged was insufficient. On the other hand, by the fixing method of the embodiment, the substrate 21A can be fixed to the heat sink 40 at 9 locations in the range where the LED chips 23A are arranged. Therefore, the warping and bending of the substrate 21A in the range where the LED chips 23A are arranged can be suppressed, and the closeness between the heat conduction member 50, the substrate 21A, and the heat sink 40 can be improved. As a result, the fixing method according to the embodiment has a higher cooling effect on the LED chip 23A than the fixing method according to the comparative example.

[0086] In this way, it is confirmed that the substrate 21A is fixed to the heat sink 40 by utilizing the recess 211 formed in the portion AR1 in the second surface 21b of the substrate 21A corresponding to the range where the LED chips 23A are arranged, thereby making it possible to effectively cool the LED 23A, compared with the case where a mechanism for fixing the substrate 1021 and the heat sink 1040 is provided outside the range where the LED chips 23A are arranged as in the comparative example.

[0087] As described above in detail, according to the present embodiment, the first light source unit OPU1 includes the substrate 21A having the first surface 21a and the second surface 21b facing each other, the LED chips 23A arranged two-dimensionally on the first surface 21a of the substrate 21A, the heat sink 40, and the heat conduction member 50 between the substrate 21A and the heat sink 40. The substrate 21A has a plurality of recesses 211 in a portion AR1 of the second surface 21b facing the range where the LED chips 23A are arranged in a plan view, the heat sink 40 has a through hole 401, and the substrate 21A and the heat sink 40 are fixed by the bolts 61 inserted through the through hole 401 and engaged with the recesses 211. Thus, for example, compared with the case where the substrate 21A and the heat sink 40 are fixed outside the range where the LED chips 23A are arranged, the warping and bending of the substrate 21A in the range where the LED chips 23A are arranged can be suppressed, and thus the closeness between the heat conduction member 50 and the substrate 21A and the heat sink 40 can be improved. Therefore, the LED chip 23A can be cooled efficiently. Thus, the brightness of the light emitted from the light emitting portion 231A can be suppressed from decreasing due to the temperature increase of the LED chip 23A.

[0088] In addition, in the present embodiment, the recessed portion 211 is a threaded hole, so that the substrate 21A and the heat sink 40 can be easily fixed by the bolts 61 .

[0089] In addition, in the present embodiment, a plurality of recesses 211 are formed in the portion AR1 opposite to the range where the LED chips 23A are arranged, and a plurality of through holes 401 are formed corresponding to the plurality of recesses 211. Thus, since the substrate 21A and the heat sink 40 can be fixed at multiple locations, the substrate 21A and the heat conduction member 50, and the heat conduction member 50 and the heat sink 40 can be closely attached to each other, and the LED chips 23A can be cooled more effectively.

[0090] In the present embodiment, the plurality of recessed portions 211 and the through holes 401 are formed at equal intervals. This allows the force acting from the bolts 61 on the substrate 21A to be uniform, thereby suppressing distortion, deflection, etc. of the substrate 21A.

[0091] In addition, in the present embodiment, the recessed portion 211 does not penetrate the substrate 21A. This can prevent the bolt 61 from contacting the LED chip 23A.

[0092] In addition, in the present embodiment, the substrate 21A is a metal substrate, so that the recessed portion 211 can be easily formed.

[0093] It should be noted that, in the above-mentioned embodiment, the heat conducting member 50 is provided between the heat sink 40 and the substrate 21A, but the heat conducting member 50 may be omitted. That is, the heat sink 40 and the substrate 21A may be fixed by the bolts 61 in such a manner that the heat sink 40 and the substrate 21A are in direct contact with each other. In this way, the LED chip 23A can also be cooled, and the brightness of the light emitted by the light emitting portion 231A of the LED chip 23A can be suppressed from decreasing due to the increase in the temperature of the LED chip 23A.

[0094] In addition, in the above-mentioned embodiment, the recessed portion 211 is a threaded hole, but the present invention is not limited thereto. The recessed portion 211 may also be a hole without a screw groove. In this case, a fixing member that fits into the recessed portion 211 may be used instead of the bolt 61, and the fixing member may be welded and fixed to the substrate 21A using an adhesive.

[0095] In addition, in the above-mentioned embodiment, a plurality of recesses 211 are provided, but it is sufficient that at least one recess 211 is formed in a portion of the second surface 21b of the substrate 21A corresponding to a portion where the LED chips 23A are arranged. In addition, the number of recesses 211 is not limited to the above-mentioned embodiment, and may be 8 or less, or may be 10 or more.

[0096] In the above embodiment, the recesses 211 are provided at equal intervals in the X1 direction and the Y1 direction, but may be provided at irregular intervals. In this case, the through holes 401 of the heat sink 40 may be formed at positions corresponding to the positions of the recesses 211 .

[0097] In the above embodiment, the radiator 40 has the flow path 402 through which the refrigerant flows, but the present invention is not limited thereto. The radiator 40 may be a fin-type radiator, for example.

[0098] In addition, in the above embodiment, if Fig.11 As shown, the control unit CTR for controlling the LED chip 23A may be arranged on the surface of the heat sink 40 opposite to the surface on which the substrate 21A is arranged. In this case, since the control unit CTR can be cooled by the heat sink 40, it is not necessary to additionally provide a mechanism for cooling the control unit CTR, and the structure of the first light source unit OPU1 can be simplified. In addition, the cable CBL for sending signals from the control unit CTR to the LED chip 23A can be prevented from becoming longer. If the cable becomes longer, noise is likely to be generated in the signal, and since the cable can be shortened, the noise can be reduced. The same is true for the second light source unit OPU2.

[0099] In addition, in the above-mentioned embodiment and modification, the illumination unit 90 includes the illumination optical system 80 including the first light source unit OPU1, the second light source unit OPU2, and the second dichroic mirror DM2, but the present invention is not limited thereto. 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 the light emitted from the first light source unit OPU1 or the second light source unit OPU2 to the light mask MSK.

[0100] The above-mentioned embodiments are preferred examples of the present invention, but are not limited thereto, and various modifications can be made without departing from the gist of the present invention.

[0101] Description of Reference Numerals

[0102] 10Exposure device

[0103] 20A 1st light source array

[0104] 20B Second light source array

[0105] 21A, 21B substrate

[0106] 21a Page 1

[0107] 21b Page 2

[0108] 23A, 23B LED chips

[0109] 30A 1st magnification optical system

[0110] 30B Second magnification optical system

[0111] 31A, 31B lens part

[0112] 40 Radiator

[0113] 50 Heat conducting components

[0114] 61 Bolt

[0115] 211 concavity

[0116] 231A, 231B light emitting unit

[0117] 401 Through hole

[0118] 80 Illumination optical system

[0119] 90 Lighting Units

[0120] 100 Projection optical unit

[0121] CTR Control Department

[0122] DM2 Second dichroic mirror

[0123] MSK Photomask

[0124] OPU1 1st light source unit

[0125] OPU2 Second Light Source Unit

[0126] P glass substrate.

Claims

1. A light source unit, comprising: A substrate having a first surface and a second surface facing each other; a plurality of light source elements arranged two-dimensionally on the first surface of the substrate; and heat sink, The substrate has at least one recessed portion formed in a portion of the second surface that is opposite to a range where the plurality of light source elements are arranged in a plan view. The heat sink has a through hole. The substrate and the heat sink are fixed by a fixing member inserted through the through hole and fitted into the recess.

2. The light source unit according to claim 1, wherein: The recessed portion is a threaded hole.

3. The light source unit according to claim 2, wherein: The fixing member is a screw.

4. The light source unit according to any one of claims 1 to 3, wherein: The radiator has a flow path through which a refrigerant flows inside the radiator.

5. The light source unit according to claim 4, wherein: The flow path is formed in a portion where the through hole is not formed.

6. The light source unit according to any one of claims 1 to 5, wherein: A plurality of the recesses are formed in a portion opposite to the range, A plurality of the through holes are formed corresponding to the plurality of the recessed portions.

7. The light source unit according to claim 6, wherein: The plurality of recesses and the plurality of through holes are formed at equal intervals.

8. The light source unit according to any one of claims 1 to 7, wherein: The recess does not penetrate through the substrate.

9. The light source unit according to any one of claims 1 to 8, wherein: A heat conducting member is provided between the heat sink and the substrate.

10. The light source unit according to claim 9, wherein: The fixing member penetrates the heat conductive member.

11. The light source unit according to any one of claims 1 to 10, wherein: The substrate is a metal substrate.

12. The light source unit according to any one of claims 1 to 11, wherein: The substrate has a thickness of 5 mm or less.

13. The light source unit according to any one of claims 1 to 12, wherein: Each of the plurality of light source elements includes a light emitting portion for emitting light. The light source unit further includes a lens array in which a plurality of lenses are arranged on a two-dimensional plane, and the lenses form magnified images of the light emitting portions of the respective plurality of light source elements.

14. The light source unit according to any one of claims 1 to 13, wherein: A control unit for controlling the plurality of light source elements is disposed on a surface of the heat sink opposite to a surface on which the substrate is disposed.

15. A lighting unit comprising: The light source unit according to any one of claims 1 to 14; and An illumination optical system that guides the light emitted from the light source unit to an illuminated object.

16. A lighting unit comprising: A plurality of light source units according to any one of claims 1 to 14; and The illumination optical system includes a synthesis optical element for synthesizing the light emitted from the plurality of light source units, and guides the synthesized light emitted from the synthesis optical element to an irradiated object.

17. An exposure device comprising: The lighting unit of claim 15 or 16; and A projection optical system projects the pattern image of the mask illuminated by the illumination unit onto a photosensitive substrate.

18. The exposure apparatus according to claim 17, wherein: The length of at least one side or the diagonal length of the photosensitive substrate is 500 mm or more.

19. An exposure method using the exposure apparatus according to claim 17 or 18, the exposure method comprising: Utilizing the lighting unit to illuminate the light shield; as well as The pattern image of the mask is projected onto a photosensitive substrate using the projection optical system.

Images