Illumination optical system, optical system adjustment method, and exposure device

Abstract

The invention provides an illumination optical system, an optical system adjustment method, and an exposure apparatus, and provides a technique capable of appropriately correcting a spread angle of light emitted from a rod integrator even if there is a variation in a numerical aperture of an optical fiber. An illumination optical system (33) is provided with a plurality of optical fibers (511), a rod integrator (55), and a variable magnification optical system (53). A plurality of optical fibers (511) transmit light from the light source. The rod integrator (55) uniformly distributes the light emitted from each of the optical fibers (511). The variable magnification optical system (53) can change the imaging magnification of the light emitted from each optical fiber (511).

Description

Technical Field

[0001] The subject matter disclosed in this specification relates to an illumination optical system, an optical system adjustment method, and an exposure apparatus. Background Art

[0002] In the past, a pattern exposure device having an illumination optical system, a modulation element (digital micromirror device (DMD) etc.) and a projection lens is known. The illumination optical system uses a laser diode as a light source to uniformly illuminate the modulation element. The projection lens irradiates the pattern light (light modulation element image) controlled by the modulation element to the resist (exposure surface). In addition, by scanning the resist with the pattern light, a desired pattern is drawn on the resist.

[0003] In order to stabilize the exposure quality in a pattern exposure device, it is required to illuminate the modulation element uniformly. Therefore, uniform light is formed by focusing the light from the light source into an optical fiber and then incident from the optical fiber into a uniform optical element called a rod integrator.

[0004] For example, Patent Document 1 discloses such an illumination optical system having a rod integrator.

[0005] Optical fiber has a core and a cladding. The core and cladding have different refractive indices, and the difference in refractive indices determines the characteristics of light propagating inside the optical fiber. If the refractive indices of the core and cladding vary due to differences in product batches, the numerical aperture (NA) of the optical fiber varies, and it may be difficult to obtain the desired light diffusion angle.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2006-171426 Summary of the invention

[0007] An object of the present invention is to provide a technology capable of appropriately correcting the divergence angle of light emitted from an optical fiber even when there is variation in the numerical aperture of the optical fiber.

[0008] In order to solve the above problems, a first method includes: a plurality of optical fibers that transmit light from a light source; a rod integrator that evenly distributes light emitted from each of the optical fibers; and a variable magnification optical system that can change the imaging magnification of light emitted from each of the optical fibers.

[0009] A second aspect is the illumination optical system of the first aspect, wherein the variable power optical system is located between the optical fiber and the rod integrator.

[0010] A third aspect is the illumination optical system of the second aspect, wherein the variable power optical system is capable of changing the imaging magnification while maintaining a focus position.

[0011] A fourth aspect is the illumination optical system of the third aspect, wherein the variable power optical system includes an objective lens, an imaging lens, and a movable lens movable between the objective lens and the imaging lens.

[0012] A fifth aspect is the illumination optical system of the second aspect, wherein the illumination optical system further comprises an angle adjustment mechanism capable of integrally tilting each of the optical fibers and the variable power optical system so as to change an incident angle of light incident on the rod integrator.

[0013] A sixth aspect is the illumination optical system according to the fifth aspect, wherein the angle adjustment mechanism can change the incident angle in the first direction.

[0014] A seventh aspect is the illumination optical system according to the sixth aspect, wherein the angle adjustment mechanism can change the incident angle in a second direction intersecting the first direction.

[0015] The eighth method is an optical system adjustment method for adjusting any one of the illumination optical systems from the first to the seventh methods, which includes: a) using a light quantity sensor to obtain the light quantity distribution of light emitted from multiple optical fibers; b) using the light quantity distribution obtained by the process a) to adjust the imaging magnification of the variable power optical system.

[0016] The ninth method is an optical system adjustment method for adjusting the illumination optical system of the eighth method, which includes: c) a process of calculating the center of gravity of the light beam emitted from the rod integrator using a light quantity sensor; and d) a process of adjusting the incident angle of the light relative to the rod integrator so that the center of gravity of the light beam becomes a predetermined position.

[0017] The tenth aspect is an exposure device, which comprises: a holding portion that holds an exposure object; an illumination optical system of any one of the first to seventh aspects; a spatial modulator that modulates light from the illumination optical system; and a scanning mechanism that uses the light modulated by the spatial modulator to scan the surface of the object held in the holding portion.

[0018] According to the illumination optical system of the first to seventh aspects, the diffusion angle of light emitted from the plurality of optical fibers can be appropriately adjusted by the variable power optical system. Therefore, even if the numerical aperture of the optical fiber varies, the diffusion angle of light can be appropriately corrected.

[0019] According to the illumination optical system of the second aspect, the light whose diffusion angle is appropriately adjusted can be made uniform by the rod integrator.

[0020] According to the illumination optical system of the third aspect, the imaging magnification can be changed without adjusting the position of the variable power optical system relative to the rod integrator.

[0021] According to the illumination optical system of the fourth aspect, the imaging magnification can be changed without changing the focus position.

[0022] According to the illumination optical system of the fifth aspect, by adjusting the incident angle of light incident on the rod integrator, the light emitted from the rod integrator can be irradiated to the object at an appropriate angle. In addition, by tilting the optical fiber and the variable power optical system integrally with the rod integrator, the total length of the tilted unit can be shortened compared to the case where the rod integrator is also tilted. Therefore, physical interference can be reduced.

[0023] According to the optical system adjustment method of the eighth aspect, the diffusion angle of light can be appropriately adjusted to a required angle by using the light quantity distribution of light.

[0024] According to the optical system adjustment method of the ninth aspect, the incident angle can be appropriately adjusted using the position of the beam center of gravity. Thus, even when there are individual differences among the plurality of optical fibers, the direction of light emitted from the rod integrator can be appropriately adjusted. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic perspective view of an exposure device including an illumination optical system according to one embodiment.

[0026] Figure 2 This is a schematic plan view of an exposure device including an illumination optical system according to an embodiment.

[0027] Figure 3 This is a diagram showing a schematic configuration of a rendering processing unit.

[0028] Figure 4 It is a diagram showing a schematic configuration of an illumination optical system according to one embodiment.

[0029] Figure 5 It is a perspective view showing an illumination optical system according to one embodiment.

[0030] Figure 6 It is a perspective view showing an illumination optical system according to one embodiment.

[0031] Figure 7 It is a plan view showing a state of measuring the light quantity distribution (intensity distribution) of the outgoing light emitted from the optical fiber bundle.

[0032] Figure 8 It is a diagram showing the light amount distribution before the diffusion angle is adjusted and the light amount distribution after the diffusion angle is adjusted.

[0033] Fig. 9 It is a diagram showing the light amount distribution before the incident angle is adjusted and the light amount distribution after the incident angle is adjusted. DETAILED DESCRIPTION

[0034] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the structural elements described in the embodiments are merely illustrative and are not intended to limit the scope of the present invention to these. In the accompanying drawings, the size and number of each part may be exaggerated or simplified as needed for easy understanding.

[0035] <1. Implementation Method>

[0036] Figure 1 It is a schematic perspective view of an exposure apparatus 1 including an illumination optical system 33 according to one embodiment. Figure 2 1 is a schematic top view of an exposure device 1 having an illumination optical system 33 according to an embodiment. The exposure device 1 is a device that irradiates the upper surface of a substrate W such as a semiconductor substrate or a glass substrate coated with a resist as a photosensitive material with spatially modulated light, thereby drawing an exposure pattern on the upper surface of the substrate W. Figure 1 As shown, the exposure apparatus 1 includes a base 10 , a stage 11 , a conveying mechanism 12 , a frame 20 , a plurality of (two in this example) image forming processing units 30 , and a control unit 40 .

[0037] The conveying mechanism 12 is a device for conveying the flat table 11 in a substantially constant posture in the horizontal direction on the upper surface of the base 10. The conveying mechanism 12 includes a main scanning mechanism 13, a sub-scanning mechanism 14, a rotating mechanism 15, a lower support plate 16, and a middle support plate 17.

[0038] The main scanning mechanism 13 is a mechanism for moving the worktable 11 in the main scanning direction. The sub-scanning mechanism 14 is a mechanism for moving the worktable 11 in the sub-scanning direction. The substrate W moves in the main scanning direction and the sub-scanning direction together with the worktable 11 through the main scanning mechanism 13 and the sub-scanning mechanism 14.

[0039] The base 10 is a support platform for supporting the workbench 11 and the conveying mechanism 12. The base 10 is in the shape of a flat plate extending in the main scanning direction and the sub-scanning direction. The lower support plate 16 is supported on the base 10 by the main scanning mechanism 13 so as to be movable in the main scanning direction. The middle support plate 17 is supported on the lower support plate 16 by the sub-scanning mechanism 14 so as to be movable in the sub-scanning direction. The workbench 11 is supported on the middle support plate 17 by the rotating mechanism 15 so as to be rotatable around a vertical axis. The workbench 11 has an upper surface on which a substrate W can be placed. A chuck pin for holding the substrate W, a plurality of adsorption holes for adsorbing the substrate W, and the like are appropriately provided on the upper surface of the workbench 11. The workbench 11 is an example of a holding portion.

[0040] The main scanning mechanism 13 is a mechanism for moving the lower support plate 16 relative to the base 10 in the main scanning direction. The main scanning mechanism 13 has two linear motors 13a. The two linear motors 13a are arranged on the lower support plate 16 at intervals in the sub-scanning direction. The linear motor 13a has a stator 131 and a mover 133. The stator 131 is arranged on the upper surface of the base 10 along the main scanning direction. That is, two stators 131 are arranged parallel to each other on the upper surface of the base 10. The mover 133 is fixed relative to the lower support plate 16.

[0041] The linear motor 13a generates magnetic attraction and repulsion between the stator 131 and the mover 133 according to a control signal from the control unit 40, and moves the mover 133 in the main scanning direction along the stator 131. Thus, the lower support plate 16 is moved in the main scanning direction.

[0042] The sub-scanning mechanism 14 is a mechanism that moves the middle support plate 17 in the sub-scanning direction relative to the lower support plate 16. The sub-scanning mechanism 14 includes a linear motor 14a and two guide mechanisms 14b.

[0043] The linear motor 14a includes a stator 141 and a mover 142. The stator 141 is disposed on the upper surface of the lower support plate 16 along the sub-scanning direction. The mover 142 is fixed to the middle support plate 17.

[0044] The two guide mechanisms 14b are arranged at intervals in the main scanning direction. Each guide mechanism 14b has a guide rail 143 and a ball bearing 144. The guide rail 143 is arranged on the upper surface of the lower support plate 16 and extends along the secondary scanning direction. That is, on the upper surface of the lower support plate 16, a ball bearing 144 with two guide rails 143 is arranged and fixed to the lower surface of the middle support plate 17. The ball bearing 144 can move along the guide rail 143 in the secondary scanning direction.

[0045] The linear motor 14a generates magnetic attraction and repulsion between the stator 141 and the mover 142 according to a control signal from the control unit 40, and moves the mover 142 in the sub-scanning direction along the stator 141. Thus, the middle support plate 17 is moved in the sub-scanning direction.

[0046] The rotating mechanism 15 is a mechanism for adjusting the angle (deflection angle) θ of the worktable 11 around the vertical axis relative to the middle support plate 17. The rotating mechanism 15 includes, for example, a motor. The rotating mechanism 15 operates the motor according to a control signal from the control unit 40 to rotate the worktable 11 around the vertical axis relative to the middle support plate 17. Thus, the angle θ of the worktable 11 is adjusted.

[0047] The frame 20 is a structure for supporting two drawing processing units 30. The frame 20 has two pillars 21 and a bridge 22. The two pillars 21 are arranged at intervals in the sub-scanning direction. Each pillar 21 extends upward from the side of the base 10. The bridge 22 extends in the sub-scanning direction and connects the upper ends of the two pillars 21. The workbench 11 holding the substrate W passes between the two pillars 21 and below the bridge 22. Each drawing processing unit 30 is mounted on the bridge 22.

[0048] Each drawing processing unit 30 includes a laser light source 31, a laser driving unit 32, an illumination optical system 33, and an optical head 34. That is, the exposure device 1 includes two optical heads 34. The two optical heads 34 are fixed to the bridge portion 22 of the frame 20 at a distance in the sub-scanning direction.

[0049] The laser light source 31, the laser driving unit 32, and the illumination optical system 33 are housed, for example, inside the bridge portion 22 of the frame 20. The laser light source 31 includes a plurality of (for example, 12) laser modules 311. The laser driving unit 32 is electrically connected to the laser light source 31. The laser driving unit 32 emits light from each laser module 311 of the laser light source 31 according to a control signal from the control unit 40. The light from each laser module 311 is incident on the illumination optical system 33.

[0050] The control unit 40 is a device for controlling the operation of each part of the exposure device 1. The control unit 40 is a computer including a processor 41 including a CPU (Central Processing Unit), a memory 42 including a RAM (Random Access Memory), and a storage unit 43 including a hard disk drive. The memory 42 and the storage unit 43 are electrically connected to the processor 41 via a bus. The storage unit 43 stores a computer program P for controlling the operation of the exposure device 1.

[0051] The control unit 40 is electrically connected to the drawing processing unit 30 including the laser driving unit 32 and the optical head 34, the main scanning mechanism 13 including the linear motor 13a, the sub-scanning mechanism 14 including the linear motor 14a, the rotating mechanism 15, etc. The processor 41 of the control unit 40 controls the operation of the above-mentioned parts of the exposure device 1 by executing the computer program P. Thus, the drawing process in the exposure device 1 is performed.

[0052] When the exposure device 1 is in operation, exposure based on the optical head 34 and conveyance of the substrate W based on the conveying mechanism 12 are performed. Specifically, while the substrate W is being conveyed in the main scanning direction by the main scanning mechanism 13, pattern light from the optical head 34 is irradiated onto the substrate W. As a result, a strip-shaped area (hereinafter referred to as a "strip-shaped area") extending in the main scanning direction on the upper surface of the substrate W is exposed. Thereafter, the workbench 11 is moved in the sub-scanning direction by the width of the strip-shaped area (the width in the sub-scanning direction) by the sub-scanning mechanism 14. The exposure device 1 repeatedly and alternately performs such exposure in the main scanning direction and conveyance of the workbench 11 in the sub-scanning direction. As a result, a pattern is drawn on the entire upper surface of the substrate W.

[0053] Figure 3 It is a diagram showing a schematic configuration of the rendering processing unit 30 . Figure 4 It is a diagram showing a schematic configuration of an illumination optical system 33 according to one embodiment.

[0054] The illumination optical system 33 includes an optical fiber bundle 51, a variable magnification optical system 53, and a rod integrator 55. The optical fiber bundle 51 includes: a plurality of (e.g., 12) optical fibers 511, each of which has a core; and a holder 513, which holds the ends of the multiple optical fibers 511 on the emission side. The optical fiber bundle 51 is formed by bundling the multiple optical fibers 511 into a bundle. In the holder 513, the ends of the multiple optical fibers 511 on the emission side are arranged in a row at equal intervals. Light from each laser module 311 of the laser light source 31 is incident on the corresponding optical fiber 511.

[0055] As a method of arranging the optical fibers 511, for example, a plurality of optical fibers 511 may be pressed against a plane provided in the holder 513. Alternatively, a plurality of V-grooves may be provided in the holder 513, and the optical fibers 511 may be inserted into each of the V-grooves. Furthermore, the optical fibers 511 may pass through a plurality of holes provided in the holder 513.

[0056] The variable magnification optical system 53 is arranged on the downstream side of the optical fiber bundle 51. Light emitted from each optical fiber 511 of the optical fiber bundle 51 is incident on the variable magnification optical system 53. The variable magnification optical system 53 can change the imaging magnification when imaging the light emitted from each optical fiber 511. The variable magnification optical system 53 can change the imaging magnification while maintaining the focus position (that is, while keeping the focus position constant). Figure 4 As shown, the variable magnification optical system 53 includes, for example, an objective lens 531, an imaging lens 533, and a movable lens 535. The movable lens 535 is movable between the objective lens 531 and the imaging lens 533. By adjusting the position of the movable lens 535, the imaging magnification is changed.

[0057] The rod integrator 55 is arranged at a position on the downstream side of the variable power optical system 53. The light emitted from the variable power optical system 53 is incident on the rod integrator 55. The rod integrator 55 evenly distributes the light emitted from each optical fiber 511 of the optical fiber bundle 51. The rod integrator 55 is a solid rod integrator having a glass rod. The rod integrator 55 causes the incident light to be totally reflected repeatedly inside the rod, and emits a rectangular light beam whose intensity is uniform in the cross section of the light beam at the output end. That is, the light emitted from the optical fiber bundle 51 forms a rectangular uniform secondary light source at the output end of the rod integrator 55. In addition, the rod integrator 55 can also be a hollow rod integrator, which is configured in a square shape by arranging four pieces of flat glass with a reflective coating so that each of the surfaces with a reflective coating surrounds a rectangular space. In this case, light is made incident on a space surrounded by four sheets of plate glass and is repeatedly totally reflected in the space, thereby emitting a rectangular light beam having uniform intensity in the beam cross section.

[0058] In this way, in the illumination optical system 33, by causing the light emitted from the laser light source 31 to be incident on the plurality of optical fibers 511, it is possible to collect and utilize a plurality of light beams in a small area. In order to obtain the amount of light required for exposure, light emitted from the plurality of optical fibers 511 is required. After the point light source distribution of the discrete optical fibers is converted into a uniform and uniform distribution by a rod integrator (uniform optical element), the spatial modulator 341 is illuminated by a plurality of lenses with a desired diffusion angle (numerical aperture) and irradiation size.

[0059] like Figure 3 As shown, the light emitted from the rod integrator 55 passes through an imaging lens and the like and enters the spatial modulator 341 of the optical head 34 .

[0060] The optical head 34 is an optical system that guides the light from the illumination optical system 33 to the upper surface of the substrate W. The optical head 34 has a spatial modulator 341 and a projection optical system 343. The spatial modulator 341 modulates the light from the illumination optical system 33 so as to form a pattern light corresponding to the input data from the control unit 40. As the spatial modulator 341, for example, a DMD (Digital Micromirror Device) which is a reflective light modulator or a GLV (Grating Light Valve) (registered trademark) which is a diffraction grating type spatial modulator can be used.

[0061] The projection optical system 343 collects the pattern light from the spatial modulator 341 and projects it onto the substrate W. Thus, a photosensitive material such as a resist applied on the upper surface of the substrate W is exposed. The projection optical system 343 includes, for example, a projection lens and a microlens array.

[0062] Figure 5 and Figure 6 FIG. 1 is a perspective view showing an illumination optical system 33 according to an embodiment. Figure 5 and Figure 6 In order to explain the positional relationship of the elements, an XYZ orthogonal coordinate system is defined. Here, the direction from the optical fiber bundle 51 toward the rod integrator 55 is set as the positive (+) X direction, and the opposite direction is set as the - (negative) X direction. In addition, toward the +X direction, the left direction is set as the +Y direction, the right direction is set as the -Y direction, the upper direction is set as the +Z direction, and the lower direction is set as the -Z direction. The Y direction is consistent with the arrangement direction of the plurality of optical fibers 511 in the optical fiber bundle 51.

[0063] like Figure 5 As shown, the illumination optical system 33 includes a first connector 57 and a second connector 59. The first connector 57 connects the holder 513 of the optical fiber bundle 51 and the variable power optical system 53. The second connector 59 connects the variable power optical system 53 and the rod integrator 55.

[0064] like Figure 5 As shown, the second connecting member 59 includes a first bracket 591, a second bracket 592, a third bracket 595, a contact plate 593, and two connecting plates 594. The first bracket 591 is fixed to the variable magnification optical system 53 via a fixing member such as a bolt. The second bracket 592 is fixed to the rod integrator 55. A cylindrical first convex portion 592a is provided on the upper surface of the second bracket 592. In addition, a cylindrical second convex portion 592b is provided on the +Y side surface and the -Y side surface of the second bracket 592, respectively.

[0065] The contact plate 593 is fixed to the first bracket 591 via a fixing member. A cutout recess 593a is provided at the end of the +X side of the contact plate 593, which is recessed in the -X direction. The cutout recess 593a contacts the first convex portion 592a. The cutout recess 593a tilts around the Z axis with the first convex portion 592a as the center, thereby adjusting the angle θ around the Z axis of the optical fiber bundle 51 and the variable magnification optical system 53 relative to the rod integrator 55. Z By adjusting the angle θ Z , adjusting the incident angle of light from the variable power optical system 53 incident on the rod integrator 55 in the Y direction (first direction).

[0066] The two connecting plates 594 are plate-shaped members that connect the second bracket 592 and the third bracket 595. One connecting plate 594 is provided on the +Y side of the second bracket 592 and the third bracket 595, and the other connecting plate 594 is provided on the -Y side of the second bracket 592 and the third bracket 595. The connecting plates 594 are fixed to the second bracket 592 and the third bracket 595 via fasteners such as bolts.

[0067] A circular through hole 594a is provided in the connecting plate 594. When the connecting plate 594 is fixed to the second bracket 592 and the third bracket 595, the second protrusion 592b of the second bracket 592 is inserted into the through hole 594a. By inserting the second protrusion 592b into the through hole 594a, the first bracket 591 and the connecting plate 594 can be tilted around the Y axis with the second protrusion 592b as the center. Thus, the angle θ of the optical fiber bundle 51 and the variable magnification optical system 53 relative to the rod integrator 55 around the Y axis with the second protrusion 592b as the center is adjusted. Y By adjusting the angle θ Y , adjusting the incident angle of light from the variable power optical system 53 incident on the rod integrator 55 in the Z direction (second direction).

[0068] Adjust angle θ Z and angle θ Y Then, the two connecting plates 594 are fixed to the first bracket 591 and the second bracket 592. That is, the positions of the optical fiber bundle 51 and the variable power optical system 53 relative to the rod integrator 55 are fixed. Thus, the incident angle of light from the variable power optical system 53 to the rod integrator 55 is fixed.

[0069] The first convex portion 592a is arranged at the same position in the X direction and the Y direction as the incident end of the rod integrator 55. In addition, the second convex portion 592b is arranged at the same position in the X direction and the Z direction as the incident end of the rod integrator 55. Therefore, according to the second connector 59, the optical fiber bundle 51 and the variable power optical system 53 can be tilted in the Y direction and the Z direction with the incident end of the rod integrator 55 as the center.

[0070] The second connector 59 integrally tilts the plurality of optical fibers 511 (specifically, the emission-side ends held by the holder 513) and the variable power optical system 53 relative to the rod integrator 55 to change the incident angle of light entering the rod integrator 55. The second connector 59 is an example of an angle adjustment mechanism.

[0071] <Adjustment of diffusion angle>

[0072] The optical fiber 511 has a difference in the refractive index of the core and the cladding depending on the manufacturing batch, and the diffusion angle (numerical aperture) of the light emitted from the optical fiber 511 may vary. For example, when the numerical aperture changes by ±0.02, the numerical aperture of the optical fiber bundle 51 can change by about ±10%. Then, the numerical aperture of the spatial modulator 341 also changes in the same way, which may cause a loss of light quantity or a reduction in resolution.

[0073] In the illumination optical system 33, the imaging magnification of the variable magnification optical system 53 of the illumination optical system 33 is adjusted in order to adjust the numerical aperture of the optical fiber bundle 51. Specifically, the imaging magnification of the variable magnification optical system 53 in the illumination optical system 33 is adjusted so that the diffusion angle (numerical aperture) of the light emitted from the rod integrator 55 (hereinafter referred to as "exit light") becomes a desired size.

[0074] Figure 7 1 is a top view showing the state of measuring the light quantity distribution (intensity distribution) of the outgoing light emitted from the optical fiber bundle 51. The light quantity distribution of the outgoing light is measured using a light quantity sensor 91. The light quantity sensor 91 has a photosensitive element such as a photodiode or a CCD (charge-coupled device) and a processing circuit for processing the signal from the photosensitive element. The light quantity sensor 91 is, for example, a linear sensor.

[0075] The illumination optical system 33 is mounted on the rotating mechanism 93. The rotating mechanism 93 is a mechanism that rotates the optical fiber bundle 51, the variable power optical system 53, and the rod integrator 55 integrally around a predetermined rotation axis. The rotation axis of the rotating mechanism 93 is set at the emission end 55E of the rod integrator 55. The light quantity sensor 91 is fixed at a position sufficiently away from the emission end 55E of the rod integrator 55. Even in the case where the light receiving surface of the light quantity sensor 91 is narrower than the diffusion of the emitted light, by rotating the emitted light using the rotating mechanism 93, the emitted light can be irradiated to the light quantity sensor 91 from one end to the other end. Thus, the light quantity of the emitted light from one end to the other end is measured.

[0076] Figure 8 1 is a diagram showing the light intensity distribution G11 before the diffusion angle is adjusted and the light intensity distribution G12 after the diffusion angle is adjusted. The light intensity distributions G11 and G12 represent Gaussian distributions. Here, in the light intensity distributions G11 and G12, the light intensity in the Gaussian distribution is 13.5% (=1 / e 2 ) is defined as the diffusion angle (numerical aperture) of the outgoing light.

[0077] When adjusting the diffusion angle, first, the light distribution G11 before adjustment is obtained. Then, the diffusion angle is calculated based on the obtained light distribution G11. Then, the imaging magnification of the variable magnification optical system 53 is adjusted so that the diffusion angle becomes the required angle. As a result, as shown in the light distribution G12, the output light having the desired diffusion angle can be obtained.

[0078] As described above, by adjusting the imaging magnification of the variable magnification optical system 53, the numerical aperture of the optical fiber bundle 51 can be adjusted to a desired numerical aperture even when there is a deviation in the numerical aperture of each optical fiber 511. As a result, the loss of light caused by the individual differences of the optical fibers 511 can be reduced. In addition, the reduction in the resolution of the pattern light when irradiating the spatial modulator 341 due to the individual differences of the optical fibers 511 can be reduced.

[0079] In addition, in this example, the light quantity sensor 91 having a smaller diffusion width than the emitted light is used, but a light quantity sensor having a light receiving surface having a larger diffusion width than the emitted light may be used instead of the light quantity sensor 91. In this case, the light quantity distribution of the emitted light can be measured without rotating the emitted light relative to the light quantity sensor.

[0080] In addition, in this example, Figure 7 As shown, the light quantity distribution of the light emitted from the rod integrator 55 is measured, but this is not necessary. For example, the light quantity distribution of the light emitted from the variable power optical system 53 can also be measured by removing the rod integrator 55. In this case, by adjusting the imaging magnification of the variable power optical system 53, the diffusion angle of the light can also be adjusted to the required angle. In this way, by configuring the variable power optical system 53 between the optical fiber bundle 51 and the rod integrator 55, the diffusion angle of the light can be adjusted even without the rod integrator 55. Therefore, the diffusion angle adjustment operation can be easily performed.

[0081] <Adjustment of incident angle>

[0082] Next, a method of adjusting the incident angle of light incident on the rod integrator 55 from the variable power optical system 53 will be described.

[0083] The emission direction of light from each optical fiber 511 is prone to individual differences due to the configuration of the optical fiber 511, the polishing angle of the end face of the optical fiber core, etc. Therefore, it is difficult to precisely control the emission direction of light with respect to the holder 513 that holds the bundle of multiple optical fibers 511. When the emission direction of light emitted from the multiple optical fibers 511 is inappropriate, the direction of the light beam emitted from the rod integrator 55 becomes emitted in an unexpected direction. As a result, light cannot be properly incident on the spatial modulator 341, and there is a possibility of light loss and reduction in resolution.

[0084] On the other hand, in the illumination optical system 33 , the optical fiber bundle 51 and the variable power optical system 53 are unitized by the first connector 57 , and the incident angle of light to the rod integrator 55 can be adjusted by tilting the unit relative to the rod integrator 55 .

[0085] In addition, in the illumination optical system 33, the incident angle in the Y direction and the incident angle in the Z direction can be adjusted respectively by tilting the optical fiber bundle 51 and the variable power optical system 53 about the Z axis and about the Y axis relative to the rod integrator 55. Here, the adjustment of the incident angle in the Y direction is described, but the incident angle in the Z direction can also be adjusted in the same manner.

[0086] Fig. 9 2 is a diagram showing the light quantity distribution G21 before the incident angle is adjusted and the light quantity distribution G22 after the incident angle is adjusted. When the incident angle is adjusted, first, the light quantity distribution G21 of the outgoing light from the rod integrator 55 is obtained. Figure 7 As shown, the light quantity distribution G21 is obtained using the light quantity sensor 91, and the beam center of gravity of the emitted light is obtained based on the obtained light quantity distribution G21. Specifically, the beam center of gravity is the peak value of the light quantity distribution or the center position of the half-value width in the light quantity distribution. Moreover, based on the calculated beam center of gravity, the angle θ of the contact plate 593 in the second connecting member 59 is adjusted. Z , so that the center of gravity of the light beam is at a predetermined position, and as a result, an outgoing light having a light quantity distribution G22 with the position of the center of gravity of the light beam corrected can be obtained. By such adjustment, the incident angle in the Y direction can be corrected to an appropriate angle. Therefore, even if there are individual differences among the plurality of optical fibers 511, light can be appropriately incident on the spatial modulator 341.

[0087] In addition, as a method of controlling the direction of the outgoing light from the rod integrator 55, a method of integrating the optical fiber bundle 51, the variable power optical system 53, and the rod integrator 55 and tilting them as a whole for adjustment can also be adopted. However, in this case, the total length of the tilted unit becomes longer, so physical interference may occur. In contrast, as in the present embodiment, by setting a structure that tilts the optical fiber bundle 51 and the variable power optical system 53 relative to the rod integrator 55, the total length of the tilted unit can be shortened. As a result, physical interference can be reduced.

[0088] <2. Modifications>

[0089] As mentioned above, although embodiment was described, this invention is not limited to the form mentioned above, Various deformation|transformation is possible.

[0090] For example, in the above-mentioned embodiment, the variable power optical system 53 is arranged between the optical fiber bundle 51 and the rod integrator 55. However, the variable power optical system 53 may be arranged on the downstream side of the rod integrator 55 so that the light emitted from the rod integrator 55 is incident on the variable power optical system 53. That is, the variable power optical system 53 may be arranged between the rod integrator 55 and the spatial modulator 341 of the optical head 34. Even with such a structure, the diffusion angle of the light emitted from the optical fiber bundle 51 can be adjusted to a desired size.

[0091] The present invention has been described in detail, but the above description is illustrative in all aspects, and the present invention is not limited thereto. Countless modifications not illustrated can be understood as examples that can be conceived without departing from the scope of the present invention. Each structure described in the above-mentioned embodiments and each modification can be appropriately combined or omitted as long as they do not contradict each other.

[0092] Description of Reference Numerals

[0093] 1Exposure device,

[0094] 11 workbench (holding part),

[0095] 13 Main scanning mechanism,

[0096] 14 scanning mechanisms,

[0097] 33Illumination optical system,

[0098] 51 Fiber bundle,

[0099] 53 variable magnification optical system,

[0100] 55 rod integrator,

[0101] 59 second connecting member (angle adjustment mechanism),

[0102] 341 spatial modulator,

[0103] 511 optical fiber,

[0104] 531 objective lens,

[0105] 533 imaging lens,

[0106] 535 movable lens.

Claims

1. An illumination optical system, characterized in that: have: a plurality of optical fibers that transmit light from a light source; a rod integrator for uniformly distributing the light emitted from each of the optical fibers; and A variable magnification optical system is capable of changing the imaging magnification of the light emitted from each of the optical fibers.

2. The illumination optical system according to claim 1, characterized in that: The variable power optical system is located between the optical fiber and the rod integrator.

3. The illumination optical system according to claim 2, characterized in that: The variable magnification optical system is capable of changing the imaging magnification while maintaining a focus position.

4. The illumination optical system according to claim 3, characterized in that: The variable power optical system includes an objective lens, an imaging lens, and a movable lens movable between the objective lens and the imaging lens.

5. The illumination optical system according to claim 2, characterized in that: The illumination optical system further includes an angle adjustment mechanism capable of integrally tilting each of the optical fibers and the variable power optical system so as to change an incident angle of light incident on the rod integrator.

6. The illumination optical system according to claim 5, characterized in that: The angle adjustment mechanism can change the incident angle in the first direction.

7. The illumination optical system according to claim 6, characterized in that: The angle adjustment mechanism can change the incident angle in a second direction intersecting the first direction.

8. An optical system adjustment method for adjusting the illumination optical system according to any one of claims 1 to 7, characterized in that: The optical system adjustment method comprises: step a of obtaining a light intensity distribution of light emitted from a plurality of optical fibers using a light intensity sensor; and and a step (b) of adjusting the imaging magnification of the variable power optical system using the light quantity distribution obtained in the step (a).

9. The optical system adjustment method for adjusting an illumination optical system according to claim 8, characterized in that: The optical system adjustment method comprises: step c) calculating the center of gravity of the light beam emitted from the rod integrator using a light quantity sensor; and and adjusting the incident angle of the light with respect to the rod integrator so that the center of gravity of the light beam is at a predetermined position.

10. An exposure device, characterized in that: have: a holding unit that holds an exposure object; The illumination optical system according to claim 1 or 2; a spatial modulator that modulates light from the illumination optical system; as well as A scanning mechanism scans the surface of the object held by the holding portion using the light modulated by the spatial modulator.

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