Illumination optical system, optical system adjustment method and exposure apparatus

Abstract

(Problem) Provides a technology that can appropriately modify the diffusion angle of light emitted from a load integrator even when there is a deviation in the numerical aperture of the optical fiber. (Solution) The illumination optical system (33) comprises a plurality of optical fibers (511), a load integrator (55), and a variable magnification optical system (53). The plurality of optical fibers (511) transmit light from a light source. The load integrator (55) distributes the light emitted from each optical fiber (511) uniformly. The variable magnification optical system (53) can change the imaging magnification of the light emitted from each optical fiber (511).

Description

Technology Field

[0001] The subject matter disclosed in this specification relates to an illumination optical system, a method for adjusting an optical system, and an exposure apparatus. Background Technology

[0002] Conventionally, a pattern exposure device is known that includes an illumination optical system, a modulating element (such as a digital mirror device (DMD)), and a projection lens. The illumination optical system uses a laser diode as a light source to uniformly illuminate the modulating element. The projection lens irradiates pattern light (image of the optical modulating element) controlled by the modulating element onto a resist (exposure surface). Additionally, by scanning the resist with the pattern light, a desired pattern is drawn on the resist.

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

[0004] An illumination optical system equipped with such a load integrator is disclosed, for example, in Patent Document 1. Prior art literature

[0005] Japanese Patent Publication No. 2006-171426 The problem to be solved

[0006] An optical fiber has a core and a clad. The core and the clad have different refractive indices, and the characteristics of the light propagating within the fiber are determined by this difference in refractive index. When deviations in the refractive indices of the core and the clad occur due to differences in product lots, the numerical aperture (NA) of the optical fiber fluctuates, and there is a concern that it may be difficult to obtain the required light diffusion angle.

[0007] The objective of the present invention is to provide a technology that can appropriately modify the diffusion angle of light emitted from an optical fiber even when there is a deviation in the numerical aperture of the optical fiber. means of solving the problem

[0008] To solve the above problem, the first embodiment comprises a plurality of optical fibers that transmit light from a light source, a load integrator that uniformly distributes light emitted from each of the optical fibers, and a variable magnification optical system capable of changing the imaging magnification of the light emitted from each of the optical fibers.

[0009] A second embodiment is an illumination optical system of the first embodiment, wherein the variable optical system is located between the optical fiber and the load integrator.

[0010] A third embodiment is an illumination optical system of the second embodiment, wherein the variable magnification optical system can change the imaging magnification while maintaining the focus position.

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

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

[0013] The sixth embodiment is an illumination optical system of the fifth embodiment, wherein the angle adjustment mechanism can change the angle of incidence in the first direction.

[0014] The seventh embodiment is an illumination optical system of the sixth embodiment, wherein the angle adjustment mechanism can change the angle of incidence in a second direction intersecting the first direction.

[0015] The eighth embodiment is an optical system adjustment method for adjusting an illumination optical system of any one of the first to seventh embodiments, comprising: a) a process of acquiring a light quantity distribution of light emitted from a plurality of optical fibers using a light quantity sensor; and b) a process of adjusting the imaging magnification of the variable magnification optical system using the light quantity distribution acquired by process a).

[0016] The ninth embodiment is an optical system adjustment method for adjusting the illumination optical system of the eighth embodiment, comprising: c) a process of calculating the center of gravity of the light beam emitted from the load integrator using a light intensity sensor; and d) a process of adjusting the angle of incidence of the light with respect to the load integrator so that the center of the light beam becomes a predetermined position.

[0017] The 10th embodiment is an exposure device comprising a holding part that holds an object to be exposed, an illumination optical system of any one of the 1st to 7th embodiments, a spatial modulator that modulates light from the illumination optical system, and a scanning mechanism that scans the surface of the object held in the holding part with light modulated by the spatial modulator. Effects of the invention

[0018] According to the illumination optical system of the first to seventh embodiments, the diffusion angle of light emitted from a plurality of optical fibers can be appropriately adjusted by the variable optical system. Therefore, even if there is a deviation in the numerical aperture of the optical fibers, the diffusion angle of the light can be appropriately corrected.

[0019] According to the second embodiment of the illumination optical system, light with an appropriately adjusted diffusion angle can be homogenized by a load integrator.

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

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

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

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

[0024] According to the optical system adjustment method of the ninth embodiment, the angle of incidence can be appropriately adjusted using the position of the center of the light beam. Thus, even if there are individual differences among multiple optical fibers, the direction of light emitted from the load integrator can be appropriately adjusted. Brief explanation of the drawing

[0025] FIG. 1 is a schematic perspective view of an exposure device equipped with an illumination optical system related to one embodiment. FIG. 2 is a schematic top view of an exposure device equipped with an illumination optical system related to one embodiment. Figure 3 is a diagram showing the schematic configuration of the drawing processing unit. FIG. 4 is a diagram showing the schematic configuration of an illumination optical system related to one embodiment. FIG. 5 is a perspective view showing an illumination optical system related to one embodiment. FIG. 6 is a perspective view showing an illumination optical system related to one embodiment. FIG. 7 is a top view showing the light quantity distribution (intensity distribution) of the emitted light from the bundle fiber. Figure 8 is a diagram showing the light intensity distribution before adjusting the diffusion angle and the light intensity distribution after adjusting the diffusion angle. Figure 9 is a diagram showing the light intensity distribution before adjusting the angle of incidence and the light intensity distribution after adjusting the angle of incidence. Specific details for implementing the invention

[0026] Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. Furthermore, the components described in these embodiments are merely examples and are not intended to limit the scope of the present invention to them. In the drawings, the dimensions or number of parts may be exaggerated or simplified as necessary for ease of understanding.

[0027] <1. Embodiment>

[0028] FIG. 1 is a schematic perspective view of an exposure device (1) equipped with an illumination optical system (33) related to one embodiment. FIG. 2 is a schematic top view of an exposure device (1) equipped with an illumination optical system (33) related to one embodiment. The exposure device (1) is a device that irradiates spatially modulated light onto the upper surface of a substrate (W), such as a semiconductor substrate or a glass substrate, on which a photosensitive material, a resist, is coated, and draws an exposure pattern on the upper surface of the substrate (W). As shown in FIG. 1, the exposure device (1) is equipped with a stand (10), a stage (11), a transport mechanism (12), a frame (20), a plurality (two in this example) of drawing processing units (30), and a control unit (40).

[0029] The conveying mechanism (12) is a device that conveys a flat stage (11) in a horizontal direction in an approximately constant position on the upper surface of the base (10). The conveying mechanism (12) has a main injection mechanism (13), a secondary injection mechanism (14), a rotation mechanism (15), a lower support plate (16), and a middle support plate (17).

[0030] The main injection mechanism (13) is a mechanism for moving the stage (11) in the main injection direction. The auxiliary injection mechanism (14) is a mechanism for moving the stage (11) in the auxiliary injection direction. The substrate (W) is moved in the main injection direction and the auxiliary injection direction together with the stage (11) by the main injection mechanism (13) and the auxiliary injection mechanism (14).

[0031] The base (10) is a support that supports the stage (11) and the return mechanism (12). The base (10) is a flat plate that expands in the main injection direction and the auxiliary injection direction. The lower support plate (16) is supported on the base (10) so as to be movable in the main injection direction by the main injection mechanism (13). The middle support plate (17) is supported on the lower support plate (16) so as to be movable in the auxiliary injection direction by the auxiliary injection mechanism (14). The stage (11) is supported on the middle support plate (17) so as to be rotatable around a vertical axis by the rotation mechanism (15). The stage (11) has an upper surface capable of holding a substrate (W). On the upper surface of the stage (11), a chuck pin for holding the substrate (W), a plurality of suction holes for adsorbing the substrate (W), etc. are appropriately formed. The stage (11) is an example of a holding part.

[0032] The injection mechanism (13) is a mechanism for moving the lower support plate (16) in the injection direction relative to the base (10). The injection mechanism (13) has two linear motors (13a). The two linear motors (13a) are spaced apart in the injection direction on the lower support plate (16). The linear motors (13a) have a stator (131) and a mover (133). The stator (131) is arranged along the injection direction on the upper surface of the base (10). 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).

[0033] The linear motor (13a), in accordance with a control signal from the control unit (40), generates magnetic attraction and repulsion between the stator (131) and the mover (133) and moves the mover (133) along the stator (131) in the direction of the main movement. As a result, the lower support plate (16) is moved in the direction of the main movement.

[0034] The auxiliary injection mechanism (14) is a mechanism for moving the middle support plate (17) in the auxiliary injection direction relative to the lower support plate (16). The auxiliary injection mechanism (14) has a linear motor (14a) and two guide mechanisms (14b).

[0035] The linear motor (14a) has a stator (141) and a mover (142). The stator (141) is positioned along the auxiliary direction on the upper surface of the lower support plate (16). The mover (142) is fixed to the middle support plate (17).

[0036] Two guide mechanisms (14b) are formed spaced apart in the main injection direction. Each guide mechanism (14b) has a guide rail (143) and a ball bearing (144). The guide rail (143) is positioned on the upper surface of the lower support plate (16) and extends along the secondary injection direction. That is, the ball bearing (144), on which two guide rails (143) are positioned on the upper surface of the lower support plate (16), is fixed to the lower surface of the middle support plate (17). The ball bearing (144) is movable along the guide rail (143) in the secondary injection direction.

[0037] The linear motor (14a), in accordance with a control signal from the control unit (40), generates magnetic attraction and repulsion forces between the stator (141) and the mover (142) and moves the mover (142) along the stator (141) in the auxiliary direction. As a result, the suspension support plate (17) is moved in the auxiliary direction.

[0038] The rotation mechanism (15) is a mechanism for adjusting the angle (yawing angle) (θ) around the vertical axis of the stage (11) relative to the suspension support plate (17). The rotation mechanism (15) is equipped with, for example, a motor. The rotation mechanism (15) operates the motor according to a control signal from the control unit (40) and rotates the stage (11) around the vertical axis relative to the suspension support plate (17). By doing so, the angle (θ) of the stage (11) is adjusted.

[0039] The frame (20) is a structure for supporting two drawing processing units (30). The frame (20) has two supporting units (21) and a bridging unit (22). The two supporting units (21) are spaced apart in the sub-scanning direction. Each supporting unit (21) extends upward from the side of the base (10). The bridging unit (22) extends in the sub-scanning direction and connects the upper ends of each of the two supporting units (21). The stage (11) holding the substrate (W) passes between the two supporting units (21) and also below the bridging unit (22). Each drawing processing unit (30) is mounted on the bridging unit (22).

[0040] Each drawing processing unit (30) is equipped with 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) is equipped with two optical heads (34). The two optical heads (34) are fixed to the cross-linking unit (22) of the frame (20) at a distance from each other in the sub-scanning direction.

[0041] A laser light source (31), a laser driver (32), and an illumination optical system (33) are housed, for example, inside a cross-section (22) of a frame (20). The laser light source (31) has a plurality (e.g., 12) of laser modules (311). The laser driver (32) is electrically connected to the laser light source (31). The laser driver (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).

[0042] The control unit (40) is a device that controls the operation of each part of the exposure device (1). The control unit (40) is a computer that includes a processor (41) including a CPU (Central Processing Unit), memory (42) such as RAM (Random Access Memory), and a storage unit (43) such as a hard disk drive. The memory (42) and the storage unit (43) are electrically connected to the processor (41) via a bus. A computer program (P) for controlling the operation of the exposure device (1) is stored in the storage unit (43).

[0043] The control unit (40) is electrically connected to the drawing processing unit (30) including a laser driving unit (32) and an optical head (34), the main scanning mechanism (13) including a linear motor (13a), the auxiliary scanning mechanism (14) including a linear motor (14a), the rotation mechanism (15), etc. The processor (41) of the control unit (40) controls the operation of each of the above parts of the exposure device (1) by executing a computer program (P). By doing so, the drawing processing in the exposure device (1) proceeds.

[0044] When the exposure device (1) is operated, exposure by the optical head (34) and transport of the substrate (W) by the transport mechanism (12) are performed. Specifically, while the substrate (W) is being transported in the main scanning direction by the main scanning mechanism (13), an image pattern light from the optical head (34) is irradiated onto the substrate (W). As a result, a strip-shaped area (hereinafter referred to as the "strip-shaped area") extending in the main scanning direction on the upper surface of the substrate (W) is exposed. Afterward, the stage (11) is moved in the sub-scanning direction by the width of one strip-shaped area (width in the sub-scanning direction) by the sub-scanning mechanism (14). The exposure device (1) alternately repeats the exposure in the main scanning direction and the transport of the stage (11) in the sub-scanning direction. As a result, a pattern is drawn on the entire upper surface of the substrate (W).

[0045] FIG. 3 is a diagram showing the schematic configuration of the drawing processing unit (30). FIG. 4 is a diagram showing the schematic configuration of the illumination optical system (33) related to one embodiment.

[0046] The illumination optical system (33) comprises a bundle fiber (51), a variable optical system (53), and a load integrator (55). The bundle fiber (51) comprises a plurality of optical fibers (511), each having one core (e.g., 12), and a holder (513) that holds the output ends of the plurality of optical fibers (511). The bundle fiber (51) is configured by bundling the plurality of optical fibers (511) into one. In the holder (513), the output ends of the plurality of optical fibers (511) are arranged in a line at equal intervals. Light from each laser module (311) of the laser light source (31) is incident on the corresponding optical fiber (511).

[0047] As a method of arranging optical fibers (511), for example, a plurality of optical fibers (511) may be placed on a flat surface formed in a holder (513). Alternatively, a plurality of V-grooves may be formed in the holder (513), and an optical fiber (511) may be inserted into each V-groove. Additionally, an optical fiber (511) may pass through a plurality of holes formed in the holder (513).

[0048] The variable magnification optical system (53) is positioned downstream of the bundle fiber (51). Light emitted from each optical fiber (511) of the bundle fiber (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 (i.e., while maintaining the focus position constant). As shown in FIG. 4, the variable magnification optical system (53) has, 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 image magnification is changed.

[0049] The rod integrator (55) is positioned downstream of the variable optical system (53). Light emitted from the variable optical system (53) is incident on the rod integrator (55). The rod integrator (55) uniformly distributes the light emitted from each light fiber (511) of the bundle fiber (51). The rod integrator (55) is a solid rod integrator having a glass rod. The rod integrator (55) emits a rectangular beam of light with uniform intensity within the beam cross-section at the output end by repeatedly total internally reflecting the incident light within the rod. That is, the light emitted from the bundle fiber (51) forms a rectangular, uniform secondary light source at the output end of the rod integrator (55). Additionally, the rod integrator (55) may be a hollow rod integrator configured by arranging four flat glass sheets with reflective coatings in an L-shape to surround a rectangular space with each of the surfaces having reflective coatings. In this case, light is incident on the space surrounded by the four flat glass sheets and is repeatedly total reflected within the space, thereby emitting a rectangular beam of light with uniform intensity within the beam cross-section.

[0050] In this way, in the illumination optical system (33), light emitted from a laser light source (31) is incident on a plurality of optical fibers (511), thereby allowing a plurality of light beams to be concentrated and utilized in a small area. In order to obtain the amount of light required for exposure, light emitted from a plurality of optical fibers (511) is required. The point light source distribution of the discrete optical fibers is converted into a uniform and even distribution by a load integrator (uniform optical element), and then the spatial modulator (341) is illuminated through a plurality of lenses with the required diffusion angle (numerical aperture) and irradiation size.

[0051] As shown in FIG. 3, light emitted from the load integrator (55) passes through an imaging lens, etc. and is incident on the spatial modulator (341) of the optical head (34).

[0052] The optical head (34) is an optical system that guides light from the illumination optical system (33) onto 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 that pattern light is formed according to input data from the control unit (40). For the spatial modulator (341), for example, a reflective light modulator such as a DMD (Digital Micromirror Device) or a diffraction grating type spatial modulator such as a GLV (Grating Light Valve) (registered trademark) can be used.

[0053] The projection optical system (343) collects pattern light from the spatial modulator (341) and projects it onto the substrate (W). As a result, a photosensitive material, such as a resist, coated 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.

[0054] FIGS. 5 and 6 are perspective views showing an illumination optical system (33) related to one embodiment. In FIGS. 5 and 6, an XYZ orthogonal coordinate system is defined to explain the positional relationship of the elements. Here, the direction from the bundle fiber (51) toward the load integrator (55) is defined as the plus (+) X direction, and the opposite direction as the minus (-) X direction. Also, toward the +X direction, the left direction is defined as the +Y direction, the right direction as the -Y direction, the upward direction as the +Z direction, and the downward direction as the -Z direction. The Y direction corresponds to the arrangement direction of the plurality of optical fibers (511) in the bundle fiber (51).

[0055] As shown in FIG. 5, the illumination optical system (33) is equipped with a first connector (57) and a second connector (59). The first connector (57) connects the holder (513) of the bundle fiber (51) with the variable optical system (53). The second connector (59) connects the variable optical system (53) with the load integrator (55).

[0056] As shown in FIG. 5, the second connector (59) has 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 optical system (53) through a fastener such as a bolt. The second bracket (592) is fixed to the rod integrator (55). A cylindrical first convex portion (592a) is formed on the upper surface of the second bracket (592). Additionally, a cylindrical second convex portion (592b) is formed on the +Y side and -Y side of the second bracket (592), respectively.

[0057] The contact plate (593) is fixed to the first bracket (591) through a fastener. A cutout concave portion (593a) that is recessed in the -X direction is formed at the +X side end of the contact plate (593). The cutout concave portion (593a) is in contact with the first convex portion (592a). As the cutout concave portion (593a) tilts around the Z-axis with the first convex portion (592a) as the center, the angle (θ) around the Z-axis of the bundle fiber (51) and the variable optical system (53) with respect to the rod integrator (55) Z ) is adjusted. Angle (θ Z By adjusting the angle of incidence in the Y direction (first direction) of the light incident from the variable optical system (53) to the load integrator (55), the angle of incidence is adjusted.

[0058] Two connecting plates (594) are plate-shaped members that connect the second bracket (592) and the third bracket (595). One connecting plate (594) is formed on the +Y side of the second bracket (592) and the third bracket (595), and the other connecting plate (594) is formed 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) through fasteners such as bolts.

[0059] A circular through hole (594a) is formed in the connecting plate (594). When the connecting plate (594) is fixed to the second bracket (592) and the third bracket (595), the second convex portion (592b) of the second bracket (592) is inserted into the through hole (594a). By inserting the second convex portion (592b) into the through hole (594a), the first bracket (591) and the connecting plate (594) can tilt around the Y-axis centered on the second convex portion (592b). As a result, the angle (θ) around the Y-axis centered on the second convex portion (592b) of the bundle fiber (51) and the variable optical system (53) relative to the rod integrator (55) Y ) is adjusted. Angle (θ Y By adjusting ), the angle of incidence in the Z direction (second direction) of the light incident from the variable optical system (53) to the load integrator (55) is adjusted.

[0060] Angle (θ Z ) and angle (θ YAfter the adjustment, two connecting plates (594) are fixed to the first bracket (591) and the second bracket (592). That is, the positions of the bundle fiber (51) and the variable optical system (53) relative to the load integrator (55) are fixed. Thus, the angle of incidence of light incident from the variable optical system (53) to the load integrator (55) is fixed.

[0061] The first convex portion (592a) is positioned at the same location as the incident end of the rod integrator (55) in the X and Y directions. Also, the second convex portion (592b) is positioned at the same location as the incident end of the rod integrator (55) in the X and Z directions. Because of this, according to the second connector (59), it is possible to tilt the bundle fiber (51) and the variable optical system (53) in the Y and Z directions around the incident end of the rod integrator (55).

[0062] The second connector (59) integrally tilts a plurality of optical fibers (511) (specifically, the output end held by the holder (513)) and a variable optical system (53) relative to the rod integrator (55) so that the angle of incidence of light incident on the rod integrator (55) is changed. The second connector (59) is an example of an angle adjustment mechanism.

[0063] <Adjustment of Diffusion Angle>

[0064] In the optical fiber (511), a difference in the refractive index between the core and the cladding may occur due to the manufacturing lot, which may cause a deviation in the diffusion angle (numerical aperture) of the light emitted from the optical fiber (511). For example, if the numerical aperture changes by ±0.02, the numerical aperture of the bundle fiber (51) may change by about ±10%. Then, since the numerical aperture of the spatial modulator (341) also changes in the same way, it may cause a loss of light or a decrease in resolution.

[0065] In the illumination optical system (33), the imaging magnification of the variable magnification optical system (53) of the illumination optical system (33) is adjusted to adjust the numerical aperture of the bundle fiber (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 (hereinafter referred to as "emitted light") emitted from the load integrator (55) becomes a desired size.

[0066] FIG. 7 is a top view showing the light quantity distribution (intensity distribution) of the emitted light emitted from the bundle fiber (51). The light quantity distribution of the emitted 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 that processes the signal from the photosensitive element. The light quantity sensor (91) is, for example, a line sensor.

[0067] The illumination optical system (33) is mounted on a rotating mechanism (93). The rotating mechanism (93) is a mechanism that integrally rotates the bundle fiber (51), the variable optical system (53), and the load integrator (55) around a predetermined rotation axis. The rotation axis of the rotating mechanism (93) is set to the output end (55E) of the load integrator (55). The light intensity sensor (91) is fixed at a position sufficiently far from the output end (55E) of the load integrator (55). Even when the light receiving surface of the light intensity sensor (91) is narrower than the diffusion of the emitted light, the emitted light is rotated by the rotating mechanism (93), so that the light intensity sensor (91) is irradiated from one end to the other end of the emitted light. In this way, the amount of light from one end to the other end of the emitted light is measured.

[0068] FIG. 8 is a diagram showing the light intensity distribution (G11) before adjusting the diffusion angle and the light intensity distribution (G12) after adjusting the diffusion angle. The light intensity distributions (G11, G12) represent Gaussian distributions. Here, in the light intensity distributions (G11, G12), the light intensity in the Gaussian distribution is 13.5% (= 1 / e 2 The half-angle of the angle that becomes ) is defined as the diffusion angle (numerical aperture) of the emitted light.

[0069] When adjusting the diffusion angle, first, the light intensity distribution (G11) before adjustment is obtained. Then, the diffusion angle is determined from the obtained light intensity distribution (G11). Then, the imaging magnification of the variable magnification optical system (53) is adjusted so that the diffusion angle becomes the required angle. In this way, as indicated by the light intensity distribution (G12), an emitted light with a desired diffusion angle can be obtained.

[0070] As described above, by adjusting the imaging magnification of the variable magnification optical system (53), the numerical aperture of the bundle fiber (51) can be adjusted to a desired numerical aperture even if there is a deviation in the numerical aperture of individual optical fibers (511). This reduces the loss of light due to individual differences in optical fibers (511). In addition, the reduction in the resolution of the pattern light when irradiated to the spatial modulator (341) due to individual differences in optical fibers (511) can be reduced.

[0071] In addition, in this example, a light intensity sensor (91) smaller than the diffusion width of the emitted light is used, but instead of the light intensity sensor (91), a light intensity sensor having a light receiving surface larger than the diffusion width of the emitted light may be used. In this case, the light intensity distribution of the emitted light can be measured without rotating the emitted light with respect to the light intensity sensor.

[0072] In addition, in this example, as shown in FIG. 7, the light quantity distribution of light emitted from the load integrator (55) is measured, but this is not mandatory. For example, the light quantity distribution of light emitted from the variable magnification optical system (53) may be measured by separating the load integrator (55). Even in this case, it is possible to adjust the light diffusion angle to the required angle by adjusting the imaging magnification of the variable magnification optical system (53). In this way, since the variable magnification optical system (53) is positioned between the bundle fiber (51) and the load integrator (55), the light diffusion angle can be adjusted even without the load integrator (55). Therefore, the work of adjusting the diffusion angle can be facilitated.

[0073] <Adjustment of Angle of Incidence>

[0074] Next, a method for adjusting the angle of incidence of light incident on the load integrator (55) from the variable optical system (53) will be explained.

[0075] The direction of light emission from each optical fiber (511) is prone to individual variations due to the arrangement of the optical fibers (511), the polishing angle of the cross-section of the optical fiber core, etc. Therefore, it is difficult to precisely control the direction of light emission for a holder (513) that holds a bundle of multiple optical fibers (511). If the direction of light emission from multiple optical fibers (511) is not appropriate, the direction of the light beam emitted from the load integrator (55) will be emitted in an unexpected direction. As a result, light is not properly incident on the spatial modulator (341), and there is a risk of light loss or a decrease in resolution.

[0076] In this regard, in the illumination optical system (33), the bundle fiber (51) and the variable optical system (53) are unitized by the first connector (57), and by tilting the unit with respect to the load integrator (55), it is possible to adjust the angle of incidence of light with respect to the load integrator (55).

[0077] In addition, in the illumination optical system (33), the bundle fiber (51) and the variable optical system (53) can be tilted around the Z-axis and Y-axis with respect to the load integrator (55), thereby allowing the angle of incidence in the Y-direction and the angle of incidence in the Z-direction to be adjusted, respectively. Here, the adjustment of the angle of incidence in the Y-direction is described, but the angle of incidence in the Z-direction can be adjusted in the same way.

[0078] FIG. 9 is a diagram showing the light intensity distribution (G21) before adjusting the angle of incidence and the light intensity distribution (G22) after adjusting the angle of incidence. When adjusting the angle of incidence, first, the light intensity distribution (G21) of the emitted light from the rod integrator (55) is acquired. The acquisition of the light intensity distribution (G21) is performed using a light intensity sensor (91) as shown in FIG. 7, and the center of the light flux of the emitted light is determined from the acquired light intensity distribution (G21). Specifically, the center of the light flux is the peak of the light intensity distribution or the central position of the full width at half maximum (FWHM) in the light intensity distribution. Then, based on the calculated center of the light flux, the angle (θ) of the contact plate (593) in the second connector (59) is set so that the center of the light flux becomes a predetermined position. Z) is adjusted, and as a result, an emitted light with a light intensity distribution (G22) in which the position of the center of the light flux is modified can be obtained. Through such adjustment, the angle of incidence in the Y direction can be modified to an appropriate angle. Therefore, even if there are individual differences among the multiple optical fibers (511), light can be appropriately incident on the spatial modulator (341).

[0079] Additionally, as a method for controlling the direction of the emitted light from the load integrator (55), the bundle fiber (51), the variable optical system (53), and the load integrator (55) may be integrated, and the entire assembly may be tilted to adjust. However, in this case, since the total length of the unit being tilted becomes long, there is a risk of physical interference. In contrast, as in the present embodiment, the bundle fiber (51) and the variable optical system (53) are configured to be tilted relative to the load integrator (55), thereby shortening the total length of the unit being tilted. This allows for the reduction of physical interference.

[0080] <2. Variations>

[0081] Although embodiments have been described above, the present invention is not limited to those described above and various modifications are possible.

[0082] For example, in the above embodiment, the variable optical system (53) is positioned between the bundle fiber (51) and the load integrator (55). However, the variable optical system (53) may be positioned downstream of the load integrator (55) so that light emitted from the load integrator (55) is incident on the variable optical system (53). That is, the variable optical system (53) may be positioned between the load integrator (55) and the spatial modulator (341) of the optical head (34). Even with such a configuration, it is possible to adjust the diffusion angle of the light emitted from the bundle fiber (51) to a desired size.

[0083] Although this invention has been described in detail, the foregoing description is illustrative in all respects and does not limit the invention. It should be interpreted that countless variations not exemplified may be conceived without departing from the scope of this invention. Each component described in each embodiment and each variation may be appropriately combined or omitted, provided that there is no contradiction. Explanation of the symbols

[0084] 1 : Exposure device 11 : Stage (Maintenance) 13: Shareholder organization 14: Subsidiary injection device 33: Illumination optical system 51 : Bundle fiber 53 : Variable optical system 55 : Load Integrator 59: Second connector (angle adjustment mechanism) 341: Space modulator 511: Optical fiber 531 : Objective lens 533 : Imaging lens 535 : Movable lens

Claims

Claim 1 An illumination optical system comprising a plurality of optical fibers for transmitting light from a light source, a load integrator for uniformly distributing light emitted from each of the optical fibers, and a variable magnification optical system capable of changing the imaging magnification of the light emitted from each of the optical fibers, wherein the variable magnification optical system is located between the optical fibers and the load integrator, and the variable magnification optical system is capable of changing the imaging magnification while maintaining a focus position. Claim 2 In claim 1, the variable optical system comprises an objective lens, an imaging lens, and a movable lens movable between the objective lens and the imaging lens, an illumination optical system. Claim 3 An illumination optical system according to claim 1, further comprising an angle adjustment mechanism capable of integrally tilting each of the optical fibers and the variable optical system so as to change the angle of incidence of light incident on the load integrator. Claim 4 In claim 3, the angle adjustment mechanism is an illumination optical system capable of changing the angle of incidence in a first direction. Claim 5 In claim 4, the angle adjustment mechanism is an illumination optical system capable of changing the angle of incidence in a second direction intersecting the first direction. Claim 6 An optical system adjustment method for adjusting an illumination optical system described in claim 1 or 2, comprising: a) a process of acquiring a light quantity distribution of light emitted from a plurality of optical fibers using a light quantity sensor; and b) a process of adjusting the imaging magnification ratio of the variable magnification optical system using the light quantity distribution acquired by process a). Claim 7 A method for adjusting an optical system according to claim 6, comprising: c) a process of calculating the center of the light beam emitted from the load integrator using a light intensity sensor; and d) a process of adjusting the angle of incidence of the light with respect to the load integrator so that the center of the light beam becomes a predetermined position. Claim 8 An exposure device comprising: a holding part for holding an object to be exposed; an illumination optical system described in either claim 1 or claim 2; a spatial modulator for modulating light from the illumination optical system; and a scanning mechanism for scanning the surface of the object held in the holding part with light modulated by the spatial modulator. Claim 9 delete Claim 10 delete

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