Illumination unit, exposure device, and exposure method

Abstract

An illumination unit is provided with: a first light source array (20A) in which a plurality of first light source elements, each of which has a first light-emitting section that emits light having a first wavelength characteristic, are arranged; a first amplification optical system (30A) that forms an amplified image of the first light-emitting section of each of the first light source elements; a first optical system (81A) into which light from the first amplification optical system is incident; a second light source array (20B) in which a plurality of second light source elements are arranged, each second light source element having a second light emitting section that emits light having a second wavelength characteristic different from the first wavelength characteristic; a second amplification optical system (30B) that forms an amplified image of the second light-emitting section of each of the second light source elements; a second optical system (81B) into which light from the second amplification optical system is incident; and a combining optical element (DM2) that combines the light from the first optical system and the light from the second optical system, the combining optical element being disposed at a position that is a rear-side focal position of the first optical system or a vicinity thereof, and that is a rear-side focal position of the second optical system or a vicinity thereof.

Description

Technical Field

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

[0002] In recent years, liquid crystal display panels are often 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 flat plate (glass substrate) by a photolithography method. An exposure device that projects an original pattern formed on a photomask onto a photoresist layer on a flat plate via a projection optical system is used as a device for the photolithography process (for example, Patent Document 1).

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

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2000-21712 Summary of the invention

[0007] According to the first disclosed form, the lighting unit comprises: a first light source array, in which a plurality of first light source elements are arranged, the first light source elements have a first light emitting portion, and the first light emitting portion emits light having a first wavelength characteristic; a first magnifying optical system, which forms a magnified image of the first light emitting portion of each of the first light source elements; a first optical system, to which the light from the first magnifying optical system is incident; a second light source array, in which a plurality of second light source elements are arranged, the second light source elements have a second light emitting portion, and the second light emitting portion emits light having a second wavelength characteristic different from the first wavelength characteristic; a second magnifying optical system, which forms a magnified image of the second light emitting portion of each of the second light source elements; a second optical system, to which the light from the second magnifying optical system is incident; and a synthetic optical element, which synthesizes the light from the first optical system and the light from the second optical system, the synthetic optical element being arranged at a position which is a rear focal position of the first optical system or in the vicinity thereof and at a position which is a rear focal position of the second optical system or in the vicinity thereof.

[0008] According to the second disclosed aspect, the exposure apparatus includes: the lighting unit; and a projection optical system configured to project a pattern image of the photomask illuminated by the lighting unit onto a photosensitive substrate.

[0009] According to a third disclosed aspect, an exposure method is an exposure method using the exposure device, and includes: illuminating the photomask using the lighting unit; and projecting a pattern image of the photomask onto the photosensitive substrate using the projection optical system.

[0010] In addition, the configuration of the embodiments described below may be appropriately modified, and at least a portion may be replaced with other configurations. Furthermore, the configuration elements whose configuration is not particularly limited are not limited to the configuration disclosed in the embodiments, and may be configured at positions where their functions can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] [ Figure 1 ] Figure 1 It is a schematic diagram showing the structure of the exposure apparatus according to the first embodiment.

[0012] [ Figure 2 ] Figure 2 This is a schematic diagram showing the configuration of the lighting unit according to the first embodiment.

[0013] [ Figure 3 ] Figure 3 (A) is a plan view schematically showing the configuration of the first light source array and the second light source array. Figure 3 (B) is a diagram schematically showing the internal structure of the first light source unit and the second light source unit.

[0014] [ Figure 4 ] Figure 4 This is a diagram showing an example of the relationship between the incident angle to the dichroic mirror and the illumination.

[0015] [ Figure 5 ] Figure 5 This is a diagram showing an example of light distribution characteristics of a light emitting portion of an LED chip.

[0016] [ Figure 6 ] Figure 6 (A) and Figure 6 (B) is a diagram for explaining an enlarged image formed on a predetermined surface in the second embodiment.

[0017] [ Figure 7 ] Figure 7 (A) and Figure 7 (B) is a diagram showing simulation results. DETAILED DESCRIPTION

[0018] 《First Implementation Mode》

[0019] based on Figure 1 to Figure 4 The exposure apparatus 10 according to the first embodiment will be described.

[0020] (Configuration of Exposure Apparatus)

[0021] First, use Figure 1 The configuration of the exposure device 10 according to the first embodiment will be described. Figure 1 This is a diagram schematically showing the configuration of the exposure apparatus 10 according to the first embodiment.

[0022] The exposure device 10 is a scanning stepper (scanner) that transfers the pattern formed on the photomask MSK to the substrate P by driving the photomask MSK and the glass substrate (hereinafter referred to as "substrate") P in the same direction and at the same speed relative to the projection optical system PL. The substrate 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.

[0023] Below, the direction (scanning direction) for driving the photomask MSK and the substrate P during scanning exposure 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 direction, θy direction and θz direction, respectively.

[0024] The exposure apparatus 10 includes an illumination system IOP, a mask stage MST holding a photomask MSK, a projection optical system PL, a main body 70 supporting these, a substrate stage PST holding a substrate P, and a control system thereof. The control system controls the components of the exposure apparatus 10 in an integrated manner.

[0025] The main body 70 includes a base (anti-vibration table) 71, a column 72A, a column 72B, an optical pressure plate 73, a support body 74, and a slider guide 75. The base (anti-vibration table) 71 is arranged on the floor F, and supports the columns 72A, 72B, etc. to eliminate vibration from the floor F. The columns 72A and 72B each have a frame shape, and the column 72A is arranged inside 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 75. The slider guide 75 includes an air ball lifter and a positioning mechanism to position the support body 74 (i.e., the photomask stage MST described later) at an appropriate position in the X-axis direction relative to the optical pressure plate 73.

[0026] The illumination system IOP is disposed above the main body 70. The illumination system IOP irradiates the photomask MSK with illumination light IL. The detailed structure of the illumination system IOP will be described below.

[0027] The photomask stage MST is supported by a support body 74. It has a pattern surface ( Figure 1The photomask MSK (the lower surface of the optical image) is fixed to the photomask stage MST by vacuum adsorption (or electrostatic adsorption), for example. The photomask stage MST is driven by a drive system including a linear motor with a predetermined stroke along the scanning direction (X-axis direction) and is slightly driven along the non-scanning direction (Y-axis direction and θz direction).

[0028] The position information of the photomask 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) provided at the end of the photomask stage MST with a length measuring beam, receives the reflected light from the moving mirror, and measures the position of the photomask stage MST. The measurement result is provided to the control device (not shown), and the control device drives the photomask stage MST via the drive system according to the measurement result of the interferometer system.

[0029] The projection optical system PL is supported on the optical platen 73 below the photomask stage 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, for example, and includes a projection area of ​​the pattern image of the photomask MSK, for example, a plurality of (e.g., 7) projection optical units 100 (multi-lens projection optical units) arranged in a zigzag manner, forming a rectangular image field with the Y-axis direction as the length direction. Here, four projection optical units 100 are arranged at predetermined intervals along the Y-axis direction, and the remaining three projection optical units 100 are separated from the four projection optical units 100 on the +X side and arranged at predetermined intervals along the Y-axis direction. For each of the plurality of projection optical units 100, for example, an equal magnification system that is telecentric on both sides is used to form an erect image. In addition, the plurality of projection areas of the projection optical units 100 arranged in a zigzag manner are collectively referred to as exposure areas.

[0030] If the illumination area on the photomask 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 photomask MSK in the illumination area is formed on the irradiation area (exposure area (conjugate with the illumination area)) on the substrate P arranged on the image plane side of the projection optical system PL by the illumination light IL that penetrates the photomask MSK. Here, a photoresist (sensing agent) is coated on the surface of the substrate P. The photomask stage MST and the substrate stage PST are driven synchronously, that is, the photomask MSK is driven along the scanning direction (X-axis direction) relative to the illumination area (illumination light IL), and the substrate P is driven along the same scanning direction relative to the exposure area (illumination light IL), thereby the substrate P is exposed and the pattern of the photomask MSK is transferred to the substrate P.

[0031] The substrate stage PST is arranged on a base (anti-vibration table) 71 below (at the -Z side) the projection optical system PL. The substrate P is held on the substrate stage PST via a substrate holder (not shown).

[0032] The position information (rotation information (including yaw (rotation θz in the θz direction), pitch (rotation θx in the θx direction), roll (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 movable mirror (or a mirror-finished reflecting surface (not shown)) disposed at the end of the substrate stage PST, and receives reflected light from the movable mirror, thereby measuring 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.

[0033] In the exposure device 10, alignment measurement (for example, Enhanced Global Alignment (EGA) etc.) is first performed during exposure, and the result is used to expose the substrate P in the following order. First, according to the instruction of the control device, the photomask stage MST and the substrate stage PST are synchronously driven along the X-axis direction. Thus, the first irradiation area on the substrate P is subjected to scanning exposure. When the scanning exposure for the first irradiation area is completed, the control device moves (steps) the substrate stage PST to a position corresponding to the second irradiation area. Moreover, the second irradiation area is subjected to scanning exposure. Similarly, the control device repeats the stepping between the irradiation areas of the substrate P and the scanning exposure of the irradiation areas, and transfers the pattern of the photomask MSK to all irradiation areas on the substrate P.

[0034] (Composition of the lighting system IOP)

[0035] 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.

[0036] Figure 2 is a diagram schematically showing the structure of the lighting unit 90. Figure 2 As shown, the lighting unit 90 includes a first light source unit OPU1 , a second light source unit OPU2 , and an illumination optical system 80 .

[0037] (Configuration of light source unit)

[0038] The first light source unit OPU1 includes a first light source array 20A and a first magnifying optical system 30A, and the second light source unit OPU2 includes a second light source array 20B and a second magnifying optical system 30B.

[0039] Figure 3 (A) is a plan view schematically showing the configuration of the first light source array 20A and the second light source array 20B. The first light source array 20A includes, for example, a plurality of ( Figure 3 (A) shows 5×5) light emitting diode (LED) chips 23A. The number of LED chips 23A can be appropriately changed as needed. Each of the multiple LED chips 23A has a light emitting portion 231A, and the peak wavelength of the light emitted from the light emitting portion 231A is in the range of 380nm to 390nm. 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 385nm. The light emitting surface of the light emitting portion 231A is a square, and the length of one side thereof is a1. The LED chips 23A are arranged at a pitch P1. The pitch P1 is the distance between the centers of adjacent LED chips 23A.

[0040] The second light source array 20B includes, for example, a plurality of ( Figure 3 (A) is 5×5) LED chips 23B. The number of LED chips 23B can be appropriately changed as needed. Each of the multiple LED chips 23B has a light-emitting portion 231B, and the peak wavelength of the light emitted from the light-emitting portion 231B is in the range of 360nm to 370nm. 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 365nm. The light-emitting surface of the light-emitting portion 231B is a square, and the length of one side is a2. The LED chips 23B are arranged at a pitch P2.

[0041] The arrangement pitch P1 of the LED chips 23A and the arrangement pitch P2 of the LED chips 23B may be the same or different. Also, the length a1 of one side of the light emitting surface of the light emitting portion 231A and the length a2 of one side of the light emitting surface of the light emitting portion 231B may be the same or different. In addition, the LED chips 23A and the LED chips 23B may be arranged on a heat sink instead of a substrate, for example.

[0042] Figure 3 (B) is a diagram schematically showing the internal structure of the first light source unit OPU1 and the second light source unit OPU2. In addition, the internal structure of the first light source unit OPU1 and the second light source unit OPU2 is the same, so the structure of the first light source unit OPU1 is representatively described here. Here, 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 approximately parallel to the optical axis OA of the light emitted by the light emitting portion 231A. Figure 3 In (B), for clarity of the drawing, only four LED chips 23A arranged in a row along the Y1 direction are shown.

[0043] like Figure 3 As shown in FIG. 2B , 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 includes 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.

[0044] In the present embodiment, each lens portion 31A includes four planoconvex lenses, but the present invention is not limited thereto, and each lens portion 31A may include, for example, two biconvex lenses or three biconvex lenses. Furthermore, each lens portion 31A may include, for example, a planoconvex lens and a biconvex lens.

[0045] In the present embodiment, the lens portion 31A magnifies and projects the light emitting portion 231A at a magnification M1=(arrangement pitch P1 of the LED chips 23A) / (length a1 of one side of the light emitting surface of the light emitting portion 231A). On the other hand, the lens portion 31B included in the second magnifying optical system 30B magnifies and projects the light emitting portion 231B at a magnification M2=(arrangement pitch P2 of the LED chips 23B) / (length a2 of one side of the light emitting surface of the light emitting portion 231B). Thus, the magnified images of the plurality of light emitting portions 231A (231B) are almost in contact with each other on the predetermined plane PP.

[0046] (Configuration of Illumination Optical System 80)

[0047] Refer again Figure 2 , the structure of the illumination optical system 80 is described. The illumination optical system 80 includes a first condensing optical system (first optical system) 81A including a first dichroic mirror DM1, a second condensing optical system 81B (second optical system), a second dichroic mirror DM2, an imaging optical system 83, a fly-eye lens FEL, an aperture stop 85, and a condensing optical system 84.

[0048] The first light-converging optical system 81A forms the 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-converging optical system 81A is the position of the pupil. The first light-converging 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 385nm. Thus, the light beam is incident on the second dichroic mirror DM2. In addition, the first light-converging optical system 81A may also be a structure without the first dichroic mirror DM1. In the above 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-converging optical system 81A so that the light beam is incident on the second dichroic mirror DM2. In addition, the first light-converging optical system 81A may be composed of one lens, or may be composed of a lens group including multiple lenses.

[0049] The second light-converging 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-converging optical system 81B is the position of the pupil. The second light-converging optical system 81B may be composed of a single lens or a lens group including a plurality of lenses.

[0050] 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 overlap.

[0051] 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. Thus, the second dichroic mirror DM2 is illuminated by the light emitted from the first light source unit OPU1 and the light emitted from the second light source unit OPU2. Through the Kohler illumination, the illumination change of the light beam of the pupil image formed by the first light-converging optical system 81A and the illumination change of the light beam of the pupil image formed by the second light-converging optical system 81B can be reduced. In addition, the second dichroic mirror DM2 may not necessarily be 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, and may also be arranged in a manner that is located near each rear focal position. Here, near means within ±100 mm, preferably within ±50 mm, and more preferably ±20 mm from the rear focus position along the optical axis. In addition, the sign here is positive in the direction in which the light from the light source travels along the optical axis, and negative in the opposite direction.

[0052] Figure 4 This is a diagram showing an example of the relationship between the incident angle and the illumination intensity on the dichroic mirror. Figure 4 In FIG. 1 , the horizontal axis represents the incident angle to the dichroic mirror, and the vertical axis represents the illuminance of the reflected light. The illuminance on the vertical axis is 1 when the illuminance of the reflected light is incident on the dichroic mirror at the designed incident angle α.

[0053] like Figure 4 As shown in FIG. 1 , when the dichroic mirror is subjected to critical illumination (i.e., when the image of the light source is formed at the position of the dichroic mirror), the incident angle of the light beam on the dichroic mirror is within the range of about ±8° of the designed incident angle α, resulting in an illumination change of more than 3%. On the other hand, when the dichroic mirror is subjected to Koehler illumination, the incident angle of the light beam on the dichroic mirror is within the range of about ±4° of the designed incident angle α, and the illumination change can be reduced to less than 1%. In this way, by performing Koehler illumination on the second dichroic mirror DM2, the difference between the illumination of the light incident on the second dichroic mirror DM2 and the illumination of the light reflected by the second dichroic mirror DM2 can be reduced, thereby realizing illumination light IL having high brightness and less illumination unevenness.

[0054] In the present embodiment, the incident angle θ of the light from the second light-converging optical system 81B to the second dichroic mirror DM2 is set to 35°. The incident angle θ of 35° means that the incident angle θ is within the range of 35°±5°. In addition, the incident angle θ is preferably greater than 25° and less than 45°, more preferably greater than 25° and less than 42°, and further preferably 35°±5°. Thus, the second dichroic mirror DM2 can reflect the light beam of the pupil image formed by the second light-converging optical system 81B with high efficiency.

[0055] return Figure 2 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.

[0056] 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 through the second dichroic mirror DM2.

[0057] The detection results of 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 detectors DT10 to DT30.

[0058] 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 fly-eye lens FEL at the same magnification. In addition, 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.

[0059] The fly-eye lens FEL is formed by arranging multiple lens elements having positive refractive power, for example, in a manner that their optical axes are parallel to the reference optical axis AX, vertically and horizontally and densely. Each lens element constituting the fly-eye lens FEL has a rectangular cross-section similar to the shape of the irradiation field to be formed on the photomask MSK (and thus the shape of the exposure area to be formed on the substrate P).

[0060] 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 its vicinity. That is, a substantial surface light source, i.e., a secondary light source, composed of multiple light source images is formed on the rear focal plane (exit plane) of the fly-eye lens FEL or in its vicinity. The light beam from the secondary light source formed on the rear focal plane (exit plane) of the fly-eye lens FEL or in its vicinity is incident on the aperture stop 85 arranged in its vicinity. In addition, in the present embodiment, the rear focal plane (exit plane) of the fly-eye lens FEL is optically conjugate with the first light source array 20A and the second light source array 20B.

[0061] The aperture stop 85 is arranged at a position substantially optically conjugate with the incident pupil plane of the projection optical unit 100, and has a variable opening portion for defining a range that contributes to the illumination of the secondary light source. The aperture stop 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 unit 100) that determines the illumination condition to a desired value by changing the aperture of the variable opening portion. The light from the secondary light source passing through the aperture stop 85 is condensed by the condensing optical system 84, and then superimposedly illuminates the photomask MSK having a predetermined pattern.

[0062] As described above in detail, the lighting unit 90 of the first embodiment includes: the first light source array 20A, in which a plurality of LED chips 23A having light emitting portions 231A emitting light having a peak wavelength of 385 nm are arranged; the first magnifying optical system 30A, in which a magnified image of the light emitting portion 231A of each LED chip 23A is formed; and the first condensing optical system 81A, in which a pupil of the magnified image formed by the first magnifying optical system 30A is formed. Furthermore, the lighting unit 90 includes: the second light source array 20B, in which a plurality of LED chips 23B having light emitting portions 231B emitting light having a peak wavelength of 365 nm are arranged; the second magnifying optical system 30B, in which a magnified image of the light emitting portion 231B of each LED chip 23B is formed; and the second condensing optical system 81B, in which a pupil of the magnified image formed by the second magnifying optical system 30B is formed. Furthermore, the illumination unit 90 includes a second dichroic mirror DM2 for superimposing the pupil image formed by the first condensing optical system 81A and the pupil image formed by the second condensing optical system 81B to form a composite image.

[0063] The light beam of the pupil image formed by the first condensing optical system 81A and the light beam of the pupil image formed by the second condensing optical system 81B perform Kohler illumination on the second dichroic mirror DM2, so that Figure 4 As described in the description, compared with the case where the second dichroic mirror DM2 is subjected to critical illumination, illumination light IL having high brightness and less illumination unevenness can be realized.

[0064] In the first embodiment, the first magnifying optical system 30A is a lens array having a plurality of lens portions 31A arranged in a manner corresponding to each of the light emitting portions 231A, and the second magnifying optical system 30B is a lens array having a plurality of lens portions 31B arranged in a manner corresponding to each of the light emitting portions 231B. Moreover, each of the lens portions 31A of the first magnifying optical system 30A is a bilateral telecentric optical system that magnifies and projects the light emitting portion 231A at a magnification ratio of (the arrangement pitch P1 of the LED chips 23A) / (the length a1 of one side of the light emitting surface of the light emitting portion 231A). Each of the lens portions 31B of the second magnifying optical system 30B is a bilateral telecentric optical system that magnifies and projects the light emitting portion 231B at a magnification ratio of (the arrangement pitch P2 of the LED chips 23B) / (the length a2 of one side of the light emitting surface of the light emitting portion 231B). Thus, a surface light source can be formed in which the magnified images of the plurality of light emitting portions 231A (231B) are almost in contact with each other on a predetermined plane PP.

[0065] Furthermore, in the first embodiment, the illumination unit 90 includes a fly-eye lens FEL that emits a light beam of a synthetic image synthesized by the second dichroic mirror DM2 as a light beam with uniform illumination distribution, and a telecentric imaging optical system 83 that projects the synthetic image synthesized by the second dichroic mirror DM2 at the same magnification on both sides of the incident end of the fly-eye lens FEL. Thus, the photomask MSK can be uniformly illuminated.

[0066] In the first embodiment, the incident angle of the light beam of the pupil image formed by the second condensing optical system 81B on the second dichroic mirror DM2 is 35°. Thus, the light beam of the pupil image formed by the second condensing optical system 81B can be reflected with high efficiency.

[0067] Furthermore, in the first embodiment, the light with a peak wavelength of 385 nm emitted from the first light source unit OPU1 is reflected by the first dichroic mirror DM1 and is incident on the second dichroic mirror DM2, but the first dichroic mirror DM1 may be omitted so that the light with a peak wavelength of 385 nm emitted from the first light source unit OPU1 is directly incident on the second dichroic mirror DM2.

[0068] Furthermore, in the first embodiment, the light emitting portion 231A of the LED chip 23A emits light with a peak wavelength of 385 nm, and the light emitting portion 231B of the LED chip 23B emits light with a peak wavelength of 365 nm, but the light emitting portion 231A of the LED chip 23A may emit light with a peak wavelength of 365 nm, and the light emitting portion 231B of the LED chip 23B may emit light with a peak wavelength of 385 nm. In such a case, the first dichroic mirror DM1 may reflect at least a portion of the light with a peak wavelength of 365 nm, and the second dichroic mirror DM2 may transmit at least a portion of the light with a peak wavelength of 365 nm and reflect at least a portion of the light with a peak wavelength of 385 nm.

[0069] In addition, the wavelength of the light emitted by the first light source unit OPU1 and the second light source unit OPU2 is not limited to the above, and the first light source unit OPU1 and the second light source unit OPU2 may be formed by appropriately combining LED chips that emit light with a peak wavelength in the range of 360nm to 440nm. For example, the first light source unit OPU1 may emit light with a peak wavelength of 405nm, and the second light source unit OPU2 may emit light with a peak wavelength of 385nm. Furthermore, the first light source unit OPU1 may emit light with a peak wavelength of 395nm, and the second light source unit OPU2 may emit light with a peak wavelength of 385nm. 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. In addition, in the case where the combination of the wavelength of the light emitted by the first light source unit OPU1 and the wavelength of the light emitted by the second light source unit OPU2 is a combination other than the first embodiment, it is preferred to appropriately change the material of the dichroic mirror according to the wavelength used.

[0070] Second Implementation Method

[0071] Next, the second embodiment will be described. The second embodiment is different from the first embodiment in the magnification M1 and the magnification M2 of the light emitting section 231A and the light emitting section 231B of the first magnification optical system 30A and the second magnification optical system 30B.

[0072] (About LED chips)

[0073] Figure 5 2 is a diagram showing an example of light distribution characteristics of the light emitting portion 231A of the LED chip 23A. Figure 5 In FIG. 1 , the solid line represents the theoretical light distribution characteristic (Lambert radiation) of the light emitting portion 231A, and the dotted line represents the actual measurement of the radiation intensity of the light emitted from the light emitting portion 231A, and the curve is obtained by approximating the measurement result with a sixth-order polynomial.

[0074] exist Figure 5 In the example, among the light emitted from the self-luminous portion 231A, the radiation intensity of the light in the range of the emission angle greater than -50° and less than 50° is higher than the radiation intensity of the Lambertian radiation, and the radiation intensity of the light in the range of the emission angle less than -50° and the range greater than 50° is lower than the radiation intensity of the Lambertian radiation. In this way, among the light emitted from the self-luminous portion 231A, there is a range of emission angles where the radiation intensity is higher than the radiation intensity of the Lambertian radiation. Therefore, it is considered that by using the light emitted from the self-luminous portion 231A with an emission angle within the above range (within the range of Figure 5 In the example, the light in the range of ±50° can increase the brightness of the light emitted from the first light source unit OPU1.

[0075] In contrast, in the second embodiment, the magnification M1 when the first magnifying optical system 30A magnifies and projects the light emitting unit 231A is set so as to satisfy the following formula (1).

[0076] P1 / a1<M1≦sinα1 / sinθ1…(1)

[0077] Here, P1 is the arrangement pitch of the LED chips 23A, a1 is the length of one side of the light emitting surface of the light emitting portion 231A, α1 is the maximum emission angle of light having a radiation intensity higher than that of Lambertian radiation among the light emitted from the light emitting portion 231A, and θ1 is the maximum emission angle of light emitted from the first magnifying optical system 30A. In addition, sinθ1 is a value that makes the ratio (σ) of the number of apertures of the illumination optical system 80 to the number of apertures of the projection optical unit 100 equal to 1. In addition, Figure 3 When the arrangement pitch P1 of the LED chips 23A in the X1 direction and the length a1 of one side of the light-emitting surface of the light-emitting portion 231A are different from the arrangement pitch P1 of the LED chips 23A in the Y1 direction and the length a1 of one side of the light-emitting surface of the light-emitting portion 231A, it is sufficient to set them in the X1 direction and the Y1 direction respectively in a manner that satisfies formula (1).

[0078] Furthermore, the magnification M2 when the second magnifying optical system 30B magnifies and projects the light emitting portion 231B is set so as to satisfy the following formula (2).

[0079] P2 / a2<M2≦sinα2 / sinθ2…(2)

[0080] Here, P2 is the arrangement pitch of the LED chips 23B, a2 is the length of one side of the light emitting surface of the light emitting portion 231B, α2 is the maximum emission angle of light having a radiation intensity higher than that of Lambertian radiation among the light emitted from the light emitting portion 231B, and θ2 is the maximum emission angle of light emitted from the second magnifying optical system 30B. In addition, sinθ2 is a value that makes the ratio (σ) of the number of apertures of the illumination optical system 80 to the number of apertures of the projection optical unit 100 equal to 1. In addition, Figure 3 When the arrangement pitch P2 of the LED chips 23B in the X1 direction and the length a2 of one side of the light-emitting surface of the light-emitting portion 231B are different from the arrangement pitch P2 of the LED chips 23B in the Y1 direction and the length a2 of one side of the light-emitting surface of the light-emitting portion 231B, it is sufficient to set them in the X1 direction and the Y1 direction respectively in a manner that satisfies formula (2).

[0081] By enlarging the light emitting portion 231A and the light emitting portion 231B by the magnification M1 satisfying the formula (1) and the magnification M2 satisfying the formula (2), the enlarged images of the light emitting surfaces of the light emitting portion 231A and the light emitting portion 231B except for the peripheral portions are in contact with each other on the predetermined plane PP. This aspect is described.

[0082] Figure 6 (A) and Figure 6 (B) is a diagram for explaining an enlarged image formed on a predetermined surface PP in the second embodiment. More specifically, Figure 6 (A) is a top view showing the arranged LED chips 23A, Figure 6 (B) is a plan view showing an enlarged image formed on a predetermined surface PP. In order to simplify the drawing, the description will be given using 2×2 rows of LED chips 23A.

[0083] like Figure 6 As shown in (A), in the light-emitting surface of the light-emitting portion 231A of the LED chip 23A, the peripheral portion is defined as the peripheral region 231b, and the region other than the peripheral region 231b is defined as the central region 231a. In the above case, if the magnified image of the light-emitting portion 231A is formed at a magnification M1 satisfying the formula (1), then Figure 6 As shown in (B), on the predetermined plane PP, the enlarged images MI1 of the central region 231a are in contact with each other, and the enlarged image MI2 of the light emitting portion 231A including the central region 231a and the peripheral region 231b is formed so as to partially overlap.

[0084] Since the light emitting section 231A and the light emitting section 231B are respectively amplified by the magnification M1 and the magnification M2 satisfying the formula (1) and the formula (2), a surface light source is formed on a predetermined surface PP by light having a radiation intensity higher than that of Lambertian radiation, thereby increasing the intensity of light emitted from the first light source unit OPU1 and the second light source unit OPU2. In other words, a surface light source is formed by light emitted from a region (central region 231a) of the light emitting surface of the light emitting section 231A and the light emitting section 231B having a radiation intensity higher than that of Lambertian radiation, thereby increasing the intensity of light emitted from the first light source unit OPU1 and the second light source unit OPU2.

[0085] [Simulation 1]

[0086] The magnification M1 of the light emitting unit 231A of the first magnifying optical system 30A was changed to simulate the illumination on a predetermined surface of the magnified image formed by the first magnifying optical system 30A. The simulation conditions are as follows.

[0087] LED chip 23A: NVSU233B manufactured by Nichia Chemical Industries, Ltd.

[0088] Length of one side of the light emitting surface of the light emitting portion 231A: 1.4 mm

[0089] Arrangement spacing P1: 4mm

[0090] α1: 50°

[0091] θ1: 8°

[0092] In this case, the condition of the magnification M1 is 4mm / 1.4mm=2.9<M1≦

[0093] sin50° / sin8°=5.5. In contrast, the illumination was simulated when the magnification M1=2.79 and the magnification M1=3.6.

[0094] Figure 7 (A) is a diagram showing the simulation results. Figure 7 In (A), the horizontal axis represents the magnification, and the vertical axis represents the illuminance ratio when the illuminance at the magnification M1 = 2.79 is set to 1. Figure 7 As shown in (A), it was confirmed that by making the magnification M1 larger than P1 / a1, the illuminance was improved compared with the case where the magnification M1 was set to P1 / a1.

[0095] [Simulation 2]

[0096] The illuminance was simulated by using an LED chip 23A different from the LED chip 23A used in the simulation 1 and changing the magnification M1 in the same manner as in the simulation 1. The simulation conditions are as follows.

[0097] LED chip 23A: NWSU333B manufactured by Nichia Chemical Industries, Ltd.

[0098] Length of one side of the light emitting surface of the light emitting portion 231A: 1.9 mm

[0099] Arrangement spacing P1: 7mm

[0100] α1: 50°

[0101] θ1: 8°

[0102] In this case, the condition of the magnification M1 is 7 mm / 1.9 mm=3.68<M1≦

[0103] sin50° / sin8° = 5.5. In contrast, the illumination was simulated when the magnification M1 = 3.68, the magnification M1 = 4.38, and the magnification M1 = 4.65.

[0104] Figure 7 (B) is a diagram showing the simulation results. Figure 7 In (B), the horizontal axis is the magnification, and the vertical axis is the illuminance ratio when the illuminance at the magnification M1=4.38 is set to 1. Figure 7 As shown in (B), it was confirmed that by making the magnification M1 larger than P1 / a1, the illuminance was improved compared with the case where the magnification M1 was set to P1 / a1.

[0105] As described in detail above, according to the second embodiment, the magnification M1 when the first magnifying optical system 30A magnifies and projects the light emitting unit 231A satisfies P1 / a1<M1≦sinα1 / sinθ1, and the magnification M2 when the second magnifying optical system 30B magnifies and projects the light emitting unit 231B satisfies P2 / a2<M2≦

[0106] sinα2 / sinθ2.

[0107] By defining the magnification M1 and the magnification M2 in this manner, a secondary light source can be formed by light having a radiation intensity higher than Lambertian radiation, and thus the intensity of light emitted from the first light source unit OPU1 and the second light source unit OPU2 can be increased.

[0108] Furthermore, in the manufacturing process of the first light source array 20A and the second light source array 20B, when the LED chips 23A and 23B are arranged on the substrate, the positions of the LED chips 23A and 23B may be offset. Due to the position offset, the illumination of the first light source array 20A and the second light source array 20B may be reduced. In the present embodiment, by making the magnification M1 and the magnification M2 respectively greater than P1 / a1 and P2 / a2, only the inner area of ​​the light-emitting surface of the light-emitting portion 231A and the light-emitting portion 231B (the area excluding the peripheral portion) can be used. Therefore, even if the LED chips 23A and 23B are offset, the reduction in illumination of the first light source array 20A and the second light source array 20B can be suppressed.

[0109] In the second embodiment, sinθ1 and sinθ2 are values ​​obtained by setting the ratio (σ) of the numerical aperture of the illumination optical system 80 to the numerical aperture of the projection optical unit 100 to 1. Thus, illumination light IL having a brightness corresponding to the numerical aperture required in the exposure device 10 can be realized.

[0110] The above-described embodiments are preferred examples of the present invention, but are not limited thereto, and various modifications may be made without departing from the gist of the present invention.

[0111] Explanation of symbols

[0112] 10: Exposure device

[0113] 20A: First light source array

[0114] 20B: Second light source array

[0115] 23A, 23B: LED chips

[0116] 30A: First magnifying optical system

[0117] 30B: Second magnifying optical system

[0118] 31A, 31B: Lens section

[0119] 81A: First focusing optical system

[0120] 81B: Second focusing optical system

[0121] 90: Lighting unit

[0122] 100: Projection optical unit

[0123] PL: Projection Optics

[0124] FEL: Flying Eye Lens

[0125] DM2: Second dichroic mirror

Claims

1. A lighting unit, characterized in that: have: A first light source array, wherein a plurality of first light source elements are arranged, wherein the first light source elements have a first light emitting portion, and the first light emitting portion emits light having a first wavelength characteristic; a first magnifying optical system for forming a magnified image of the first light emitting portion of each of the first light source elements; a first optical system into which the light from the first amplifying optical system is incident; A second light source array, wherein a plurality of second light source elements are arranged, wherein the second light source elements have a second light emitting portion, and the second light emitting portion emits light having a second wavelength characteristic different from the first wavelength characteristic; a second magnifying optical system for forming a magnified image of the second light emitting portion of each of the second light source elements; a second optical system into which the light from the second amplifying optical system is incident; and a synthesis optical element that synthesizes the light from the first optical system and the light from the second optical system, The synthetic optical element is arranged at a position which is a rear focal position of the first optical system or its vicinity and at a position which is a rear focal position of the second optical system or its vicinity.

2. The lighting unit according to claim 1, characterized in that: The first magnifying optical system is a first lens array having a plurality of first lens portions arranged in a manner corresponding to each of the first light emitting portions. The second magnifying optical system is a second lens array including a plurality of second lens portions arranged to correspond to the respective second light emitting portions.

3. The lighting unit according to claim 2, characterized in that: The first lens units of the first lens array are each a bilateral telecentric optical system that magnifies and projects the first light-emitting unit at a magnification greater than (the arrangement pitch of the first light source elements) / (the length of one side of the light-emitting surface of the first light-emitting unit). The second lens portions of the second lens array are each a bilateral telecentric optical system that magnifies and projects the second light emitting portion at a magnification greater than (arrangement pitch of the second light source elements) / (length of one side of the light emitting surface of the second light emitting portion).

4. The lighting unit according to any one of claims 1 to 3, characterized in that: have: a light homogenizing element for emitting the light synthesized by the synthesizing optical element as a light beam with uniform illumination distribution; and The imaging optical system with two telecentric sides projects the light synthesized by the synthesis optical element to the incident end of the light uniformization element at the same magnification or reduced size.

5. The lighting unit according to claim 4, characterized in that: The light homogenizing element is a fly-eye lens.

6. The lighting unit according to any one of claims 1 to 5, characterized in that: The first light emitting portion and the second light emitting portion are ultraviolet light emitting diodes respectively.

7. The lighting unit according to any one of claims 1 to 6, characterized in that: The peak wavelength of light emitted from the first light emitting portion is within a range of 380 nm to 390 nm.

8. The lighting unit according to any one of claims 1 to 7, characterized in that: The peak wavelength of light emitted from the second light emitting portion is within a range of 360 nm to 370 nm.

9. The lighting unit according to any one of claims 1 to 8, characterized in that: The synthetic optical element is a dichroic mirror that transmits at least a portion of the light having the first wavelength characteristic and reflects at least a portion of the light having the second wavelength characteristic.

10. The lighting unit according to any one of claims 1 to 8, characterized in that: The synthetic optical element is a dichroic mirror that reflects at least a portion of the light having the first wavelength characteristic and transmits at least a portion of the light having the second wavelength characteristic.

11. The lighting unit according to any one of claims 1 to 10, characterized in that: The incident angle of the light from the second optical system on the synthetic optical element is greater than or equal to 25° and less than 45°.

12. The lighting unit according to any one of claims 1 to 10, characterized in that: The incident angle of the light from the second optical system on the synthetic optical element is greater than or equal to 25° and less than or equal to 42°.

13. The lighting unit according to any one of claims 1 to 10, characterized in that: The incident angle of the light from the second optical system to the synthetic optical element is 35°.

14. An exposure device, characterized in that: have: A lighting unit as claimed in any one of claims 1 to 13; and The projection optical system projects the pattern image of the photomask illuminated by the illumination unit onto the photosensitive substrate.

15. The exposure device according to claim 14, characterized in that The length of at least one side or diagonal length of the photosensitive substrate is 500 mm or more.

16. An exposure method using the exposure apparatus according to claim 14 or 15, And include: illuminating the photomask using the illumination unit; and The pattern image of the photomask is projected onto the photosensitive substrate using the projection optical system.

Images