TW202417999A - Light source unit, illumination unit, exposure device, and exposure method - Google Patents

Abstract

The purpose of the present invention is to, by inhibiting warpage or bending of a substrate on which light source elements are arranged, improve adhesion between the substrate and a heat sink and increase cooling efficiency. This light source unit comprises: a substrate that has a first surface and a second surface that are opposite each other; a plurality of light source elements that are two-dimensionally arranged on the first surface of the substrate; and a heat sink. The substrate has at least one recess formed in a portion of the second surface opposing a range in which 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 together by a fixing member that is inserted through the through hole and is fitted into the recess.

Description

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

The invention relates to a light source unit, an illumination unit, an exposure device, and an exposure method.

In recent years, liquid crystal display panels are often used as display components for personal computers or televisions. Liquid crystal display panels are manufactured by forming a circuit pattern of thin film transistors on a flat plate (glass substrate) using a photolithography method. An exposure device is used as a device for the photolithography process to project the original pattern formed on the mask onto the photoresist layer on the flat plate through a projection optical system.

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

[Patent Document 1] Japanese Patent Application Publication No. 2006-201476

According to the first invention aspect, the light source unit comprises: a substrate having a first surface and a second surface facing each other; a plurality of light source elements two-dimensionally arranged on the first surface of the substrate; and a heat sink; the substrate having at least one recess formed in the second surface opposite to a portion where the plurality of light source elements are arranged in a plan view, the heat sink having a through hole, and the substrate and the heat sink being fixed by a fixing member inserted through the through hole and engaged in the recess.

According to the second aspect of the invention, the lighting unit comprises: the light source unit mentioned above; and a lighting optical system that guides the light emitted from the light source unit to the illuminated object.

According to the third invention aspect, the lighting unit comprises: a plurality of the above-mentioned light source units; and a lighting optical system, which includes a synthetic optical element for synthesizing the light emitted from the plurality of the above-mentioned light source units, and guides the synthetic light emitted from the above-mentioned synthetic optical element to the irradiated object.

According to the fourth aspect of the invention, the exposure device comprises: the above-mentioned illumination unit; and a projection optical system, which projects the pattern image of the mask illuminated by the above-mentioned illumination unit onto the photosensitive substrate.

According to the fifth aspect of the invention, the exposure method is an exposure method using the above-mentioned exposure device, and includes: using the above-mentioned illumination unit to illuminate the photomask; and using the above-mentioned projection optical system to project the pattern image of the above-mentioned photomask onto the photosensitive substrate.

Furthermore, the configuration of the following embodiments may be appropriately improved, and at least a portion of the configuration may be replaced with other configurations. Furthermore, the configuration of the components that are not particularly limited is not limited to the configuration disclosed in the embodiments, and may be configured at a position that can achieve its function.

An exposure device 10 according to an embodiment will be described based on FIGS. 1 to 8 .

(Structure of exposure device) First, the structure of an exposure device 10 in an embodiment is described using FIG. 1 is a diagram schematically showing the structure of an exposure device 10 in an embodiment.

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

Hereinafter, the direction for driving the mask MSK and the plate P during scanning exposure (scanning direction) is set as the X-axis direction, the direction in the horizontal plane orthogonal to it is set as the Y-axis direction, the direction orthogonal 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 the θx, θy and θz directions, respectively.

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 the same, a substrate stage PST holding a plate P, and a control system thereof. The control system controls the components of the exposure device 10 in a comprehensive manner.

The main body 70 has a base (anti-vibration table) 71, columns 72A, 72B, an optical pressure plate 73, a support body 74 and a slider guide seat 75. The base (anti-vibration table) 71 is arranged on the floor F, and supports the columns 72A, 72B, etc. by eliminating the vibration from the floor F. The columns 72A and 72B have a frame shape, respectively, and the column 72A is arranged on the inner side of the column 72B. The optical pressure 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 slider guide seat 75. The slider guide seat 75 has an air ball lifter and a positioning mechanism to position the support body 74 (i.e., the mask platform MST described below) at an appropriate position in the X-axis direction relative to the optical pressure plate 73.

The illumination system IOP is disposed above the main body 70. The illumination system IOP irradiates the illumination light IL to the mask MSK. The detailed structure of the illumination system IOP will be described below.

The mask stage MST is supported on the support 74. The mask MSK having a pattern surface (lower surface in FIG. 1 ) on which a circuit pattern is formed is fixed to the mask stage MST by, for example, vacuum adsorption (or electrostatic adsorption). The mask stage MST is driven by, for example, a driving system including a linear motor with a predetermined stroke along a scanning direction (X-axis direction) and is slightly driven along a non-scanning direction (Y-axis direction and θz direction).

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) processed by the mirror) at the end of the mask stage MST with a length measuring beam, receives the reflected light from the moving mirror, and measures the position of the mask stage MST. The measurement result is provided to the control device (not shown), and the control device drives the mask stage MST through the drive system according to the measurement result of the interferometer system.

The projection optical system PL is supported on the optical pressure plate 73 below the mask platform MST (-Z side). The projection optical system PL is configured in the same manner as the projection optical system disclosed in the specification of U.S. Patent No. 5,729,331, and includes a plurality of (e.g., 7) projection optical units 100 (multi-lens projection optical units) arranged in a saw-tooth shape, for example, for the projection area of the pattern image of the mask MSK, forming a rectangular image field with the Y-axis direction as the longitudinal direction. Here, 4 projection optical units 100 are arranged at a predetermined interval along the Y-axis direction, and the remaining 3 projection optical units 100 are separated from the 4 projection optical units 100 on the +X side and arranged at a predetermined interval along the Y-axis direction. For example, each of the plurality of projection optical units 100 is used to form an erect image using a telecentric equal magnification system on both sides. In addition, the plurality of projection areas of the projection optical unit 100 arranged in a sawtooth shape are collectively referred to as an exposure area.

If the illumination area on the mask MSK is illuminated by the illumination light IL from the illumination system IOP, the projection image (partially erected image) of the circuit pattern of the mask MSK in the illumination area is formed in the irradiation area (exposure area (cosymmetric with the illumination area)) on the flat plate P arranged on the image plane side of the projection optical system PL by the illumination light IL passing through the mask MSK. Here, a photoresist (sensing agent) is coated on the surface of the flat plate P. The mask stage MST and the substrate stage PST are driven synchronously, that is, the mask MSK is driven along the scanning direction (X-axis direction) relative to the illumination area (illumination light IL), and the flat plate P is driven along the same scanning direction relative to the exposure area (illumination light IL), whereby the flat plate P is exposed and the pattern of the mask MSK is transferred to the flat plate P.

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

The position information (rotation information (including yaw (rotation θz in the θz direction), sway (rotation θx in the θx direction), and lateral sway (rotation θy in the θy direction)) of the substrate stage PST in the XY plane is measured by the interferometer system. The interferometer system irradiates a length measuring beam from the optical pressure plate 73 to a moving mirror (or a reflective surface processed by a mirror (not shown)) disposed at the end of the substrate stage PST, and receives the reflected light from the moving mirror to measure the position of the substrate stage PST. The measurement result is supplied to a control device (not shown), and the control device drives the substrate stage PST according to the measurement result of the interferometer system.

In the exposure device 10, alignment measurement (such as EGA, etc.) is performed before exposure, and the result is used to expose the flat plate P in the following order. First, according to the instructions of the control device, the mask stage MST and the substrate stage PST are synchronously driven along the X-axis direction. Thereby, the first irradiation area on the flat plate P is subjected to scanning exposure. When the scanning exposure of the first irradiation area is completed, the control device moves (steps) the substrate stage PST to a position corresponding to the second irradiation area. Then, the second irradiation area is subjected to scanning exposure. Similarly, the control device repeats the stepping between the irradiation areas of the flat plate P and the scanning exposure of the irradiation areas to transfer the pattern of the mask MSK to all irradiation areas on the flat plate P.

(Configuration of the illumination system IOP) Next, the configuration of the illumination system IOP in this embodiment is described. The illumination system IOP has a plurality of illumination units 90 that correspond to the plurality of projection optical units 100 of the projection optical system PL. FIG. 2 is a diagram schematically showing the configuration of the illumination unit 90.

The lighting unit 90 includes a first light source unit OPU1 , a second light source unit OPU2 , and a lighting optical system 80 .

(Structure of light source unit) The first light source unit OPU1 has a heat sink 40, a first light source array 20A, and a first amplifying optical system 30A, and the second light source unit OPU2 has a heat sink 40, a second light source array 20B, and a second amplifying optical system 30B.

Fig. 3(A) is a front view schematically showing the structure of the first light source array 20A and the second light source array 20B, and Fig. 3(B) is a cross-sectional view taken along line A-A of Fig. 3(A). In Fig. 3(B), the hatching of the LED chips 23A and 23B described below is omitted.

As shown in FIG3(A), the first light source array 20A includes a substrate 21A and a plurality of (5×5 in FIG3(A)) LED (Light Emitting Diode) chips 23A arranged two-dimensionally on the substrate 21A. The number of LED chips 23A can be appropriately changed as needed.

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.

Each of the plurality of 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. 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 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. Furthermore, 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 is orthogonal to the Y1 direction. 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.

The second light source array 20B has a substrate 21B and a plurality of (5×5 in FIG. 3 (A)) LED chips 23B arranged two-dimensionally on the substrate 21B. The number of LED chips 23B can be changed as needed. The substrate 21B also has a first surface 21a and a second surface 21b facing each other, and LED chips 23B are arranged on the first surface 21a. 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 can be the same or different.

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. That is, the light emitting portion 231B is a UV LED. The peak wavelength of the light emitted from the light emitting portion 231B is 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.

FIG. 4 is a rear view of the substrates 21A and 21B. The substrates 21A and 21B are metal substrates with a thickness of 5 mm or less. The substrates 21A and 21B are preferably made of a material with high thermal conductivity, such as a copper substrate. As shown in FIG. 3 (B) and FIG. 4, in the second surface 21b opposite to the first surface 21a of the substrates 21A and 21B, a plurality of recesses 211 (3×3 in FIG. 4) are formed in a portion AR1 opposite to the range where the plurality of LED chips 23A and 23B are arranged in a top view. In this embodiment, the plurality of recesses 211 are arranged at equal intervals in the X1 direction and the Y1 direction.

As shown in FIG3(B) , the recess 211 does not penetrate the substrates 21A and 21B. In this embodiment, the recess 211 is a screw hole, which will be described in detail below. The substrates 21A and 21B can be fixed to the heat sink 40 by engaging the bolts 61 in the recess 211 .

FIG. 5 is a perspective view showing the heat sink 40 and the first light source array 20A, and FIG. 6 is a perspective view showing the surface on the -Z1 side of the heat sink 40. FIG. 7 (A) is a front view showing the heat sink 40 and the first light source array 20A, and FIG. 7 (B) is a cross-sectional view taken along the A-A line of FIG. 7 (A). The relationship between the second light source array 20B and the heat sink 40 is the same as the relationship between the first light source array 20A and the heat sink 40, so the heat sink 40 and the first light source array 20A will be described below. Furthermore, FIG. 5 shows, as an example, a case where the first light source array 20A has 10×14 LED chips 23A. In FIG. 7 (B), the hatching of the LED chips 23A is omitted.

For example, as shown in FIG. 5 and FIG. 7 (A), in this embodiment, three first light source arrays 20A are arranged on the heat sink 40. Furthermore, the number of the first light source arrays 20A arranged on the heat sink 40 is not limited to three, and may be less than two or more than four. In other words, as long as at least one first light source array 20A is arranged on the heat sink 40, it will suffice.

As shown in FIG6 , the heat sink 40 has a flow path 402 through which a refrigerant passes, 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 provided in the first light source array 20A. The refrigerant may be a liquid or a gas, preferably water. If the temperature of the LED chip 23A rises, the brightness of the light from the light-emitting portion 231A provided in the LED chip 23A decreases. In other words, the light-emitting efficiency of the LED chip 23A decreases as the temperature rises. By using the heat sink 40 to cool the LED chip 23A, the decrease in the brightness of the light emitted from the first light source array 20A can be suppressed.

As shown in FIG. 6 and FIG. 7 (B), the heat sink 40 has a through hole 401 that penetrates the heat sink 40. The through hole 401 is a stepped through hole whose diameter 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. Furthermore, the through hole 401 is provided at a position corresponding to the recess 211 provided on the second surface 21b of the substrate 21A provided in the first light source array 20A.

As shown in FIG. 7 (B), a thermally conductive member 50 such as a Thermal Interface Material (TIM) is provided between the substrate 21A and the heat sink 40. In this embodiment, a thermally conductive sheet is used as the thermally conductive member 50. The thermally conductive member 50 may also be thermally conductive grease or the like. The thermally conductive member 50 is provided in a manner of contacting 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. In this way, a small gap or unevenness between the substrate 21A and the heat sink 40 is filled, and the LED chips 23A can be efficiently cooled using the heat sink 40.

The heat sink 40 and the substrate 21A are fixed by bolts 61 inserted through the through holes 401 and engaged (fitted) in the recesses 211. The bolts 61 penetrate the heat conductive member 50. The length of the bolts 61 is set to a length such that the heat sink 40 and the heat conductive member 50 and the substrate 21A and the heat conductive member 50 are in close contact with each other while penetrating the heat conductive member 50. In this way, the LED chips 23A can be cooled more efficiently by using the heat sink 40. Furthermore, in the present embodiment, the heat conductive member 50 is provided corresponding to each of the first light source arrays 20A, but for example, a single sheet-shaped heat conductive member 50 may be provided in three first light source arrays 20A.

Next, the first amplifying optical system 30A and the second amplifying optical system 30B are described. Fig. 8 is a diagram for describing the first amplifying optical system 30A and the second amplifying optical system 30B respectively provided in the first light source unit OPU1 and the second light source unit OPU2.

As shown in FIG8 , 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. Each of the lens portions 31A is a bilateral telecentric optical system that magnifies and projects 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). Furthermore, in FIG8 , for the sake of clarity of the diagram, only four LED chips 23A (23B) arranged in a row along the Y1 direction are shown.

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. Each lens portion 31B is a telecentric optical system that magnifies and projects 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).

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

(Composition of the illumination optical system 80) Returning to FIG. 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 compound eye lens FEL, and a light-collecting optical system 84.

The first focusing 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 focus position of the first focusing optical system 81A is the position of the pupil. The first focusing 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. Thereby, the light beam is incident on the second dichroic mirror DM2. Furthermore, the first focusing optical system 81A may also be configured without the first dichroic mirror DM1. In this case, the configuration of the first light source unit OPU1 and the configuration of each lens of 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 composed of a single lens or a lens assembly including a plurality of lenses.

The second focusing optical system 81B forms a pupil of the magnified image of the light emitting portion 231B formed by the second magnifying optical system 30B. That is, the rear focus position of the second focusing optical system 81B is the position of the pupil. The second focusing optical system 81B may be composed of a single lens or a lens assembly including a plurality of lenses.

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 condensing optical system 81A and the pupil image formed by the second condensing optical system 81B are superimposed.

In the present embodiment, the second dichroic mirror DM2 overlaps the pupil image formed by the first light-converging optical system 81A and the pupil image formed by the second light-converging optical system 81B to form a composite image. That is, the second dichroic mirror DM2 is arranged at a position that is the rear focal position of the first light-converging optical system 81A and the rear focal position of the second light-converging optical system 81B. Thereby, the second dichroic mirror DM2 is Kohler illuminated by the light emitted from the first light source unit OPU1 and the light emitted from the second light source unit OPU2. Kohler illumination can reduce the illumination variation of the light beam of the pupil image formed by the first light-converging optical system 81A and the illumination variation of the light beam of the pupil image formed by the second light-converging optical system 81B. Furthermore, the configuration is not limited to the present embodiment, and the first focusing optical system 81A and the second focusing optical system 81B may be configured to respectively perform critical illumination on the second dichroic mirror DM2 to form the image of the first light source unit OPU1 and the image of the second light source unit OPU2.

The lighting 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.

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.

The detection results of the detectors DT10 to DT30 are output to a control device not shown in the figure. 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.

The imaging optical system 83 is a telecentric optical system on both sides that projects the composite image synthesized by the second dichroic mirror DM2 to the incident end of the compound eye lens FEL at the same magnification. Furthermore, the imaging optical system 83 can also project the composite image synthesized by the second dichroic mirror DM2 to the incident end of the compound eye lens FEL at a reduced size.

The compound eye lens FEL is formed by arranging a plurality of lens elements having positive refractive power, for example, in a manner that their optical axes are parallel to the reference optical axis AX. Each lens element constituting the compound eye lens FEL has a rectangular cross section similar to the shape of the irradiation field to be formed on the mask MSK (and thus the shape of the exposure area to be formed on the plate P).

Therefore, the light beam incident on the compound eye lens FEL is divided by the wavefronts of a plurality of lens elements, and a light source image is formed on the rear focal plane (exit plane) or in the vicinity of each lens element. That is, a substantial surface light source, i.e., a secondary light source, composed of a plurality of light source images is formed on the rear focal plane (exit plane) or in the vicinity of the compound eye lens FEL. The light beam from the secondary light source formed on the rear focal plane (exit plane) or in the vicinity of the compound eye lens FEL is incident on the aperture 85 arranged in the vicinity thereof. Furthermore, in the present embodiment, the rear focal plane (exit plane) of the compound eye lens FEL is optically conjugate with the first light source array 20A and the second light source array 20B.

The aperture diaphragm 85 is arranged at a position substantially optically coaxial with the incident pupil plane of the projection optical system PL, and has a variable opening portion for a predetermined range of illumination that helps the secondary light source. Moreover, the aperture diaphragm 85 sets the σ value (the ratio of the aperture of the secondary light source image on the pupil plane to the aperture of the pupil plane of the projection optical system) that determines the illumination condition to a desired value by changing the aperture of the variable opening portion. After the light from the secondary light source passing through the aperture diaphragm 85 is focused by the focusing optical system 84, the light mask MSK having a predetermined pattern is superimposedly illuminated.

Furthermore, 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 appropriately combined with LED chips that emit light with a peak wavelength in the range of 360 to 440 nm. For example, the first light source unit OPU1 may emit light with a peak wavelength of 405 nm, and the second light source unit OPU2 may emit light with a peak wavelength of 385 nm. Furthermore, the first light source unit OPU1 may emit light with a peak wavelength of 395 nm, and the second light source unit OPU2 may emit light with 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 the examples described above. Furthermore, when 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 set to a combination other than the first embodiment, it is better to appropriately change the material of the color separation mirror according to the wavelength to be used.

(Experiment) 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 was set to 5×5.

(Comparative Example) First, the fixing method of the heat sink 1040 and the substrate 1021 of the comparative example is described. FIG9 (A) is a front view of the heat sink 1040 and the light source array 1020 of the comparative example, and FIG9 (B) is a cross-sectional view taken along the A-A line of FIG9 (A).

As shown in FIG9 (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 and arrangement pitch of the LED chips 23A arranged on the substrate 1021 are the same as those of the first light source array 20A.

As shown in Fig. 9(B), the heat sink 1040 of the comparative example has a through hole 1401 and a fixing block 45. The fixing block 45 is fixed to the heat sink 1040 by a bolt 46. A screw hole is formed at the end of the fixing block 45 on the +Z1 side.

The substrate 1021 is provided with through holes at four locations outside the range where the plurality of LED chips 23A are arranged. The substrate 1021 is fixed to the heat sink 1040 by inserting bolts 60 from the +Z1 side into the through holes and engaging with the screw holes formed at the ends of the +Z1 side of the fixing block 45. Since the other structures are the same as those of the embodiment, detailed description is omitted.

As shown in FIG9 (A), a thermistor 25 is arranged on the surface of the substrate 1021, and the surface temperature of the substrate 1021 is measured. Similarly, a 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. FIG10 is a diagram showing the measurement results.

The horizontal axis of FIG. 10 represents each substrate, "left" represents the substrate arranged on the -Y1 side, "center" represents the substrate arranged on the center, "right" represents the substrate arranged on the +Y1 side, and "average" represents the average value of all substrates. The vertical axis of FIG. 10 represents the temperature obtained based on the measured value of the thermistor 25.

As shown in FIG. 10 , it was confirmed that in any substrate, by fixing the heat sink 40 and the substrate 21A using the method of the embodiment, the surface temperature of the substrate was lowered compared to the method of the comparative example. That is, it was confirmed that the fixing method of the embodiment had a higher cooling effect on the LED chip 23A than the fixing method of the comparative example. The reason is considered to be as follows. In the fixing method of the comparative example, since the substrate 1021 is fixed to the heat sink 1040 at four locations outside the range where the plurality of LED chips 23A are arranged, the substrate 1021 is warped or distorted, resulting in insufficient adhesion between the thermal conductive member 50 and the substrate 1021 and the heat sink 1040 in the range where the LED chips 23A are arranged. On the other hand, in the fixing method of the embodiment, since the substrate 21A can be fixed to the heat sink 40 at nine locations within the range where the LED chips 23A are arranged, the warping or bending of the substrate 21A within the range where the LED chips 23A are arranged can be suppressed, and the adhesion between the thermal conductive member 50 and the substrate 21A and the heat sink 40 can be improved. As a result, it is considered that the fixing method of the embodiment has a higher cooling effect on the LED chip 23A than the fixing method of the comparative example.

In this way, it is confirmed that by fixing the substrate 21A to the heat sink 40 by utilizing the recess 211 of the portion AR1 formed in the second surface 21b of the substrate 21A corresponding to the range where the LED chips 23A are arranged, the LED 23A can be efficiently cooled, compared to the case where the substrate 1021 and the heat sink 1040 are fixed by setting a mechanism for fixing the substrate 1021 and the heat sink 1040 outside the range where the LED chips 23A are arranged as in the comparative example.

As described above, according to the present embodiment, the first light source unit OPU1 includes a substrate 21A having a first surface 21a and a second surface 21b facing each other, LED chips 23A arranged two-dimensionally on the first surface 21a of the substrate 21A, a heat sink 40, and a heat conducting member 50 provided 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 bolts 61 inserted through the through hole 401 and fitted into the recess 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 or bending of the substrate 21A within the range where the LED chips 23A are arranged can be suppressed, so that the close contact between the heat conductive member 50 and the substrate 21A and the heat sink 40 can be improved. Therefore, the LED chips 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 chips 23A.

In this embodiment, the recessed portion 211 is a screw hole, so that the base plate 21A and the heat sink 40 can be simply fixed by the bolt 61 .

Furthermore, 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 a plurality of locations, the substrate 21A and the heat conducting member 50, and the heat conducting member 50 and the heat sink 40 can be brought into close contact, and the LED chips 23A can be cooled more efficiently.

Furthermore, in the present embodiment, a plurality of recesses 211 and through holes 401 are formed at intervals. This makes it possible to make the force acting from the bolts 61 on the substrate 21A uniform, thereby suppressing the strain, deflection, etc. of the substrate 21A.

Furthermore, in this embodiment, the recess 211 does not penetrate the substrate 21A. This prevents the bolt 61 from contacting the LED chip 23A.

In this embodiment, the substrate 21A is a metal substrate, so that the recess 211 can be easily formed.

Furthermore, 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 a manner that the heat sink 40 and the substrate 21A are in direct contact with each other. Even so, the LED chip 23A can 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.

In the above embodiment, the recess 211 is a screw hole, but the present invention is not limited thereto. The recess 211 may also be a hole without a thread groove. In this case, a fixing member fitted in the recess 211 may be used instead of the bolt 61, and the fixing member may be fixed to the substrate 21A by welding or adhesive.

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

In the above embodiment, the recesses 211 are arranged at equal intervals in the X1 direction and the Y1 direction, but they may also be arranged 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.

In the above embodiment, the heat sink 40 has a flow path 402 for circulating the refrigerant therein, but the present invention is not limited thereto. The heat sink 40 may be a fin-type heat sink, for example.

Furthermore, in the above-mentioned embodiment, as shown in FIG. 11 , a control unit CTR for controlling the LED chip 23A can 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 heat sink 40 can be used to cool the control unit CTR, there is no need to separately provide a mechanism for cooling the control unit CTR, and the structure of the first light source unit OPU1 can be simplified. Furthermore, the length of the cable CBL for sending signals from the control unit CTR to the LED chip 23A can be suppressed. If the cable becomes longer, the noise in the signal tends to increase, and since the cable can be shortened, the noise can be reduced. The same is true for the second light source unit OPU2.

In the above-mentioned embodiments and variations, 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 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 mask MSK.

The above embodiments are preferred embodiments of the present invention, but are not limited thereto, and various modifications can be implemented without departing from the scope of the present invention.

10: Exposure device 20A: First light source array 20B: Second light source array 21A, 21B: Substrate 21a: First surface 21b: Second surface 23A, 23B: LED chip 25: Thermistor 30A: First magnification optical system 30B: Second magnification optical system 31A, 31B: Lens unit 40: Heat sink 41: Supply port 42: Discharge port 45: Fixing block 46: Bolt 50: Heat conducting member 60: Bolt 61: Bolt 70: Main body 71: Base (anti-vibration table) 72A, 72B: Column 73: Optical platen 74: Support body 75: Slider guide seat 80: Illumination optical system 81A: First focusing optical system 81B: Second focusing optical system 83: Imaging optical system 84: Focusing optical system 85: Aperture thimble 90: Illumination unit 100: Projection optical unit 211: Recess 212: Pillar 213: Recess 221: Insulation layer 222: Wiring layer 223: Solder paste 231A, 231B: Light-emitting part 401: Through hole 402: Flow path 1020: Light source array 1021: Substrate 1040: Heat sink 1401: Through hole CBL: Cable CTR: Control unit AR1: Part AX: Reference optical axis a1, a2: Length DM1: 1st dichroic mirror DM2: 2nd dichroic mirror DT10, DT20, DT30: Detector F: Floor FEL: Compound eye lens IL: Illumination light IOP: Illumination system MSK: Mask MST: Mask platform OA: Optical axis OPU1: 1st light source unit OPU2: 2nd light source unit P: Glass substrate P1, P2: Pitch PL: Projection optical system PP: Predetermined surface PST: Substrate platform

[FIG. 1] is a schematic diagram showing the structure of an exposure device of an embodiment. [FIG. 2] is a schematic diagram showing the structure of an illumination unit. [FIG. 3 (A)] is a front view of the first and second light source arrays, and [FIG. 3 (B)] is a cross-sectional view taken along the A-A line of FIG. 3 (A). [FIG. 4] is a rear view of the substrate. [FIG. 5] is a three-dimensional view showing a heat sink and the first light source array. [FIG. 6] is a three-dimensional view showing the surface on the -Z1 side of the heat sink. [FIG. 7 (A)] is a front view showing a heat sink and the first light source array, and [FIG. 7 (B)] is a cross-sectional view taken along the A-A line of FIG. 7 (A). [FIG. 8] is a diagram for explaining the first and second magnifying optical systems. [Figure 9 (A)] is a front view showing the heat sink and light source array of the comparative example, and [Figure 9 (B)] is a cross-sectional view taken along the A-A line of Figure 9 (A). [Figure 10] is a diagram showing the measurement results of the surface temperature of the substrate. [Figure 11] is a cross-sectional view for explaining the modified example.

20A: 1st light source array

21A: Substrate

23A: LED chip

40: Heat sink

50: Heat conducting components

61: Bolts

401:Through hole

Claims (19)

A light source unit comprises: 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 a heat sink; the substrate having at least one recess formed in the second surface opposite to the range where the plurality of light source elements are arranged in a plan view; the heat sink having a through hole; the substrate and the heat sink being fixed by a fixing member inserted through the through hole and engaged in the recess. As in claim 1, the light source unit, wherein the above-mentioned recess is a screw hole. As in claim 2, the light source unit, wherein the above-mentioned fixing member is a screw. A light source unit as claimed in any one of claims 1 to 3, wherein the heat sink has a flow path for the refrigerant to pass through the interior of the heat sink. A light source unit as claimed in claim 4, wherein the flow path is formed in a portion where the through hole is not formed. A light source unit as claimed in any one of claims 1 to 5, wherein the above-mentioned recessed portions are formed in a plurality in the portion opposite to the above-mentioned range, and the above-mentioned through holes are formed in a plurality corresponding to the above-mentioned recessed portions. As in claim 6, the light source unit, wherein the plurality of recesses and the plurality of through holes are formed at equal intervals. A light source unit as claimed in any one of claims 1 to 7, wherein the recess does not pass through the substrate. A light source unit as claimed in any one of claims 1 to 8, comprising: A heat-conducting member disposed between the heat sink and the substrate. As in claim 9, the light source unit, wherein the fixing member passes through the heat-conducting member. A light source unit as claimed in any one of claims 1 to 10, wherein the substrate is a metal substrate. A light source unit as claimed in any one of claims 1 to 11, wherein the substrate has a thickness of less than 5 mm. A light source unit as claimed in any one of claims 1 to 12, wherein each of the plurality of light source elements has a light-emitting portion for emitting light, and the light source unit further comprises: a lens array, which arranges a plurality of lenses on a two-dimensional plane to form a magnified image of the light-emitting portion of each of the plurality of light source elements. A light source unit as claimed in any one of claims 1 to 13, wherein a control unit for controlling the plurality of light source elements is disposed on the surface of the heat sink opposite to the surface on which the substrate is disposed. A lighting unit comprising: a light source unit as claimed in any one of claims 1 to 14; and an illumination optical system that guides light emitted from the light source unit to an illuminated object. A lighting unit, comprising: A plurality of light source units as in any one of claims 1 to 14; and An illumination optical system, comprising a synthesis optical element for synthesizing light emitted from the plurality of light source units, and guiding the synthesized light emitted from the synthesis optical element to an illuminated object. An exposure device comprising: an illumination unit as claimed in claim 15 or 16; and a projection optical system that projects a pattern image of a photomask illuminated by the illumination unit onto a photosensitive substrate. The exposure device of claim 17, wherein the length or diagonal length of at least one side of the photosensitive substrate is greater than 500 mm. An exposure method, which is an exposure method using the exposure device of claim 17 or 18, and includes: Utilizing the above-mentioned illumination unit to illuminate the photomask; and Utilizing the above-mentioned projection optical system to project the pattern image of the above-mentioned photomask onto a photosensitive substrate.

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