Illumination optical system, exposure apparatus, and device manufacturing method

Abstract

This illumination optical system (IL1, IL2), which illuminates an irradiated surface, comprises a light source unit (LS1, LS2), a fly-eye lens (5), and a condenser lens (6) by which a plurality of light beams from the fly-eye lens are superimposed on the irradiated surface. The light source unit is provided with: a first light-emitting part having a first light-emitting surface (1Le, 1Me, 1Se) and a first optical element (3), the first light-emitting part emitting, via the first optical element, a first light beam emitted from the first light-emitting surface; and a second light-emitting part having a second light-emitting surface (1Le, 1Me, 1Se) and a second optical element (3), the second light-emitting part emitting, via the second optical element, a second light beam emitted from the second light-emitting surface. The light source unit is configured to selectively emit either the first light beam from the first light-emitting part or the second light beam from the second light-emitting part. The second light-emitting part is configured so that the shape or dimensions of a cross-section of the second beam at an incidence surface of the fly-eye lens differs from the shape or dimensions of a cross-section of the first beam at the incidence surface of the fly-eye lens.

Description

Illumination optical system, exposure apparatus, and device manufacturing method

[0001] The present invention relates to an illumination optical system, an exposure apparatus, and a device manufacturing method.

[0002] An exposure apparatus used in the manufacture of various devices such as semiconductor devices includes an illumination optical system that irradiates a pattern formed on a mask with light, and a projection optical system that forms an image of the pattern on a substrate by focusing the light that has passed through the pattern on the substrate. With the increasing diversification of patterns in recent years, illumination optical systems are required to be able to realize a variety of illumination conditions according to the characteristics of the patterns.

[0003] An aperture stop is disposed on the optical path of an illumination optical system (see, for example, Japanese Patent Application Laid-Open No. 2003-122999). One type of aperture stop is known as a variable-diameter aperture stop that can change illumination conditions.

[0004] JP 2016-188878 A

[0005] Changing the illumination conditions using an aperture diaphragm is done by blocking part of the light from the light source, which results in a loss of light intensity (power loss) due to the absorption of part of the light energy by the aperture diaphragm.

[0006] An object of the present invention is to provide an illumination optical system, an exposure apparatus, and a device manufacturing method that are capable of changing illumination conditions while suppressing loss of light intensity.

[0007] According to a first aspect of the present invention, there is provided an illumination optical system for illuminating an illuminated surface, comprising: a light source unit; a fly's eye lens arranged in an optical path between the light source unit and the illuminated surface; and a condenser lens for superimposing a plurality of light beams from the fly's eye lens on the illuminated surface, wherein the light source unit comprises: a first light emitting unit having a first light emitting surface and a first optical element, and emitting a first light beam emitted from the first light emitting surface via the first optical element; and a second light emitting unit having a second light emitting surface and a second optical element, and emitting a second light beam emitted from the second light emitting surface via the second optical element, wherein the illumination optical system is configured to selectively emit the first light beam from the first light emitting unit or the second light beam from the second light emitting unit, and wherein the second light emitting unit is configured such that the shape or size of the cross section of the second light beam at the incident surface of the fly's eye lens is different from the shape or size of the cross section of the first light beam at the incident surface of the fly's eye lens.

[0008] According to a second aspect of the present invention, there is provided an exposure apparatus for exposing a pattern on a mask onto a substrate, comprising: an illumination optical system of the first aspect that illuminates the pattern; and a projection optical system that forms an image of the pattern on the substrate.

[0009] According to a third aspect of the present invention, there is provided an exposure apparatus that scans and exposes a pattern on a mask onto a substrate, comprising: a plurality of illumination optical systems of a first aspect that illuminate the pattern; a plurality of projection optical systems that form an image of the pattern on the substrate; and a control unit that controls the scanning exposure, wherein the plurality of illumination optical systems include a first illumination optical system that irradiates a first illumination area with illumination light and a second illumination optical system that irradiates a second illumination area with illumination light, the first illumination area and the second illumination area overlap in a non-scanning direction that is perpendicular to the scanning direction in which the exposure apparatus performs the scanning exposure, and the control unit is configured to change the illuminance distribution of the second illumination optical system based on the illuminance distribution of the first illumination optical system.

[0010] According to a fourth aspect of the present invention, there is provided a device manufacturing method including: exposing a pattern on a mask onto a substrate using the exposure apparatus of the second or third aspect; developing the substrate onto which the pattern has been exposed, and forming a mask layer having a shape corresponding to the pattern on the surface of the substrate; and processing the surface of the substrate via the mask layer.

[0011] According to the illumination optical system, exposure apparatus, and device manufacturing method of the present invention, it is possible to change the illumination conditions while suppressing loss of light quantity.

[0012] FIG. 1 is a diagram schematically illustrating the configuration of exposure apparatuses according to first and second embodiments of the present invention. FIG. 2 is a diagram schematically illustrating the internal configuration of an illumination optical system according to the first embodiment of the present invention. FIG. 3 is a diagram schematically illustrating the configuration of a fiber group in a light source unit according to the first embodiment. FIG. 4 is a diagram illustrating the arrangement of multiple light-emitting surfaces in the light-emitting region of a light source unit according to the first embodiment. FIG. 5(a) is a diagram illustrating the optical path when only the output end of a large-diameter fiber is emitting light in the illumination optical system according to the first embodiment of the present invention. FIG. 5(b) is a diagram illustrating the state in which only the output end of a large-diameter fiber is emitting light in the light-emitting region of the light source unit. FIG. 5(c) is a diagram illustrating an image formed on the incident plane of a fly's-eye lens by light from the large-diameter fiber. FIG. 6(a) is a diagram illustrating the optical path when only the output end of a medium-diameter fiber is emitting light in the illumination optical system according to the first embodiment of the present invention. FIG. 6(b) is a diagram illustrating the state in which only the output end of a medium-diameter fiber is emitting light in the light-emitting region of the light source unit. FIG. 6(c) is a diagram illustrating an image formed on the incident plane of a fly's-eye lens by light from the medium-diameter fiber. FIG. 7(a) is a diagram showing the optical path when only the output end of the small-diameter fiber is emitting light in the illumination optical system of the first embodiment of the present invention. FIG. 7(b) is a diagram showing the state in which only the output end of the small-diameter fiber is emitting light in the light-emitting region of the light source unit. FIG. 7(c) is a diagram showing an image formed on the incident plane of the fly's-eye lens by light from the small-diameter fiber. FIG. 8(a) is a graph showing the illuminance distribution formed on the illuminated surface by light emitted from three large-diameter fibers. FIG. 8(b) is a graph showing the state in which the tilt component of the illuminance is corrected by adjusting the output of the semiconductor laser. FIG. 9 is a diagram showing the positional relationship between the optical fiber end face and the collector lens in the light source unit of the illumination optical system of a modified example of the first embodiment. FIG. 10(a) is a diagram showing the optical path when only the output end of the normal illumination fiber is emitting light in the illumination optical system of the second embodiment of the present invention. FIG. 10(b) is a diagram showing an image formed on the incident plane of the fly's-eye lens by light from the normal illumination fiber. FIG. 11 is a diagram schematically showing the configuration of the fiber group in the light source unit of the second embodiment. FIG. 12 is a diagram showing the arrangement of a plurality of light-emitting surfaces in the light-emitting region of the light source unit of the second embodiment.Fig. 13(a) shows the optical path when only the output end of the annular illumination fiber is emitting light in the illumination optical system of the second embodiment of the present invention, and Fig. 13(b) shows an image formed on the incident plane of the fly's eye lens by light from the output end of the annular illumination fiber. Fig. 14(a) shows the optical path when only the output end of the quadrupole illumination fiber is emitting light in the illumination optical system of the second embodiment of the present invention, and Fig. 14(b) shows an image formed on the incident plane of the fly's eye lens by light from the output end of the quadrupole illumination fiber. Fig. 15 is a diagram showing the arrangement of the output ends of the optical fibers, the axicon lens, the collector lens, and two relay lenses in the light source section of the illumination optical system of a modified example. Fig. 16 is a diagram schematically showing the internal configuration of the illumination optical system of a modified example. In this illumination optical system, an image of the output end of the optical fiber arranged in the light-emitting region is formed near the output plane of the fly's eye lens. Fig. 17 is a flowchart showing the manufacturing process of a semiconductor device. Fig. 18 is a flowchart showing the manufacturing process of a liquid crystal device such as a liquid crystal display element.

[0013] First Embodiment An illumination optical system IL1 and exposure apparatus EX of a first embodiment will be described with reference to FIGS.

[0014] [Overall Configuration of Exposure Apparatus] The exposure apparatus EX is a step-and-scan projection exposure apparatus (a so-called scanner) that scans and exposes an image of a pattern formed on a mask onto a substrate.

[0015] As shown in FIG. 1, the exposure apparatus EX mainly comprises an illumination unit IU, a mask stage MST, five projection optical systems PL arranged in a staggered pattern, a substrate stage PST, and a controller CONT1.

[0016] In the following description, the direction in which the optical axis AX of each of the five projection optical systems PL extends is referred to as the Z-axis direction. Furthermore, within a plane perpendicular to the Z-axis direction, the direction in which the mask M and substrate P are synchronously moved during scanning exposure (scanning direction) is referred to as the X-axis direction, and the direction orthogonal to the X-axis direction within the plane (non-scanning direction) is referred to as the Y-axis direction. Note that these X-axis, Y-axis, and Z-axis directions are defined for convenience of explanation and may be changed as desired. For example, when determining the X-axis, Y-axis, and Z-axis directions in an actual apparatus, the X-axis direction in this specification may be referred to as the Y-axis direction, and the Y-axis direction in this specification may be referred to as the X-axis direction.

[0017] The illumination unit IU is composed of five illumination optical systems IL1 (FIG. 2) that have the same internal configuration. Each of the five illumination optical systems IL1 irradiates a rectangular illumination area ILA with illumination light for exposure (exposure light). The five illumination optical systems IL1 are arranged in a staggered pattern, similar to the five projection optical systems PL, with their optical axes Ax aligned with the Z-axis direction. The internal configuration of the illumination optical system IL1 will be described later.

[0018] The mask stage MST holds the mask M approximately parallel to the XY plane so that the upper surface of the mask M is positioned in the illumination area ILA of the illumination optical system IL1. The mask stage MST is driven by a mask stage drive system (not shown) to move in the X direction, Y direction, and in a rotational direction around the Z axis. The position of the mask stage MST is measured by a mask stage measurement system (not shown).

[0019] Each projection optical system PL focuses the exposure light that has passed through the mask M within a trapezoidal field area A1 onto a trapezoidal exposure area A2 on the substrate P. In this way, an image of the pattern of the mask M is formed (exposed) on the substrate P.

[0020] Specifically, each of the projection optical systems PL is, for example, a double-telecentric optical system that forms an erect image. Optical systems that can be used as the projection optical system PL are described in, for example, Japanese Patent Application Laid-Open Nos. 7-57986 and 2001-215718 filed by the present applicant.

[0021] The substrate stage PST holds the substrate P substantially parallel to the XY plane on the image plane side of the projection optical system PL. The substrate stage PST is driven by a substrate stage drive system (not shown) to move in the X direction, Y direction, and in a rotational direction around the Z axis. The position of the substrate stage PST is measured by a substrate stage measurement system (not shown).

[0022] The control unit CONT1 controls the overall driving of the illumination unit IU, the mask stage MST, the projection optical system PL, and the substrate stage PST.

[0023] [Illumination Optical System IL1] The illumination optical system IL1 will be described.

[0024] 2 to 5, the illumination optical system IL1 mainly includes a light source section LS1, a relay lens 4, a fly-eye lens 5, and a condenser lens 6. The light source section LS1 mainly includes an optical fiber (light guide) group 1, a semiconductor laser unit (light source device) 2, a plurality of collector lenses 3, and a control section (illuminance distribution control section) CONT2.

[0025] As shown in Figure 3, the optical fiber group 1 is composed of a large diameter fiber group 1LG including a plurality of large diameter fibers 1L, a medium diameter fiber group 1MG including a plurality of medium diameter fibers 1M, and a small diameter fiber group 1SG including a plurality of small diameter fibers 1S.

[0026] Each of the plurality of large-diameter fibers 1L included in the large-diameter fiber group 1LG has an incident end 1Li to which light from the semiconductor laser unit 2 is incident, and an exit end (light-emitting surface) 1Le from which the incident light is emitted. Each large-diameter fiber 1L branches into two on a path from the incident end 1Li to the exit end 1Le, and has two exit ends 1Le for one incident end 1Li. The core diameter of the large-diameter fiber 1L on the exit end 1Le side may be approximately 1.1 mm to 1.4 mm, or approximately 1.06 mm to 1.33 mm.

[0027] Each of the plurality of medium diameter fibers 1M included in the medium diameter fiber group 1MG has an incident end 1Mi into which light from the semiconductor laser unit 2 is incident, and an exit end (light emitting surface) 1Me from which the incident light is emitted. Each of the medium diameter fibers 1M branches into three on a path from the incident end 1Mi to the exit end 1Me, and has three exit ends 1Me for one incident end 1Mi. The core diameter of the medium diameter fiber 1M on the exit end 1Me side may be approximately 0.5 mm to 0.9 mm, or approximately 0.53 mm to 0.8 mm.

[0028] Each of the plurality of small diameter fibers 1S included in the small diameter fiber group 1SG has an incident end 1Si into which light from the semiconductor laser unit 2 is incident, and an exit end (light emitting surface) 1Se from which the incident light is emitted. Each small diameter fiber 1S branches into four on a path from the incident end 1Si to the exit end 1Se, and each incident end 1Si has four exit ends 1Se. The core diameter of the small diameter fiber 1S on the exit end 1Se side may be approximately 0.2 mm to 0.7 mm, or approximately 0.26 mm to 0.53 mm.

[0029] To avoid complicating the drawings, only three large diameter fibers 1L are shown in FIG. 2, and only one large diameter fiber 1L, one medium diameter fiber 1M, and one small diameter fiber 1S are shown in FIGS. 5 to 7.

[0030] Each of the output ends 1Le of the large-diameter fibers 1L, the output end 1Me of the medium-diameter fibers 1M, and the output end 1Se of the small-diameter fibers 1S all have a circular, flat surface. As shown in Fig. 4, the output ends 1Le, 1Me, and 1Se are arranged flush with one another in a plane perpendicular to the optical axis Ax of the illumination optical system IL1. Here, the planar region where the output ends 1Le, 1Me, and 1Se are arranged flush with one another is referred to as the light-emitting region EA1.

[0031] In the light emitting area EA1, the arrangement of the emission ends 1Le, 1Me, and 1Se is as follows.

[0032] The output ends 1Le of the large diameter fibers 1L are arranged in a matrix of three rows in the X direction and two columns in the Y direction. In the X direction, the output ends 1Le are arranged at equal intervals, and the center of the central output end 1Le is aligned with the optical axis Ax. In the Y direction, the midpoint between two output ends 1Le aligned with each other in the Y direction is aligned with the optical axis Ax. In this way, the output ends 1Le of the large diameter fibers 1L are arranged in point symmetry in the light-emitting area EA1 with the position of the optical axis Ax as the point of symmetry.

[0033] The output ends 1Me of the medium diameter fibers 1M are arranged in a matrix of three rows in the X direction and three columns in the Y direction. In the X direction, the output ends 1Me are arranged at equal intervals, and the center of the central output end 1Me is located at the same position as the optical axis Ax. In the Y direction, the output ends 1Me are also arranged at equal intervals, and the center of the central output end 1Me is located at the same position as the optical axis Ax. In this way, the output ends 1Me of the medium diameter fibers 1M are arranged in point symmetry in the light-emitting area EA1, with the position of the optical axis Ax as the point of symmetry.

[0034] The emission ends 1Se of the small-diameter fibers 1S are arranged in a matrix of three rows in the X direction and four columns in the Y direction. The distance between the emission end 1Se in the first column and the emission end 1Se in the second column, and the distance between the emission end 1Se in the third column and the emission end 1Se in the fourth column, from one end in the Y direction, are equal to each other and are greater than the distance between the emission end 1Se in the second column and the emission end 1Se in the third column. In the X direction, the three emission ends 1Se are arranged at equal intervals, and the center of the central emission end 1Se is aligned with the optical axis Ax. In the Y direction, the midpoint between the emission end 1Se in the second column and the emission end 1Se in the third column from one end in the Y direction is aligned with the optical axis Ax. Thus, the emission ends 1Se of the small-diameter fibers 1S are arranged in point symmetry in the light-emitting area EA1, with the optical axis Ax as the symmetry point.

[0035] By arranging the multiple exit ends 1Le, the multiple exit ends 1Me, and the multiple exit ends 1Se in point symmetry with the position of the optical axis Ax as the symmetry point, the uniformity of the illuminance distribution in the illumination area ILA of the illumination optical system IL1 is improved (details will be described later).

[0036] In this embodiment, the multiple exit ends 1Le are arranged point-symmetrically with respect to the optical axis Ax, and are also arranged line-symmetrically with respect to a reference line that passes through the optical axis Ax and extends in the X-axis direction, and are also arranged line-symmetrically with respect to a reference line that passes through the optical axis Ax and extends in the Y-axis direction. The same applies to the multiple exit ends 1Me and the multiple exit ends 1Se. In this way, multiple exit ends of the same type may be arranged line-symmetrically with respect to a reference line that passes through the optical axis Ax and extends in the X-axis direction and / or a reference line that passes through the optical axis Ax and extends in the Y-axis direction, rather than point-symmetrically with respect to the optical axis Ax.

[0037] In this embodiment, because the X direction is the scanning direction of the exposure apparatus EX, the uniformity of the illuminance distribution in the direction perpendicular to the scanning direction (Y axis direction) can be improved by arranging multiple exit ends of the same type (for example, multiple exit ends 1Le) in line symmetry with respect to a reference line that extends in the scanning direction (X axis direction) and passes through the optical axis Ax. In contrast, even if multiple exit ends of the same type are not arranged in line symmetry with respect to a reference line that extends in the Y axis direction and passes through the optical axis Ax, the illuminance distribution in the X axis direction is made uniform by scanning exposure.

[0038] The semiconductor laser unit 2 includes three semiconductor lasers (laser diodes), and is configured so that the light beams from the semiconductor lasers are emitted parallel to each other from different positions.

[0039] The semiconductor laser unit 2 is moved by a moving mechanism 21 to cause the light beams from the three semiconductor lasers to be incident on any one of the three incident ends 1Li included in the large diameter fiber group 1LG, the three incident ends 1Mi included in the medium diameter fiber group 1MG, or the three incident ends 1Si included in the small diameter fiber group 1SG.

[0040] The light incident on each of the input ends 1Li is repeatedly internally reflected within the large-diameter fiber 1L, and then emitted from each of the output ends 1Le with a substantially uniform light intensity distribution. The same is true for the light incident on each of the input ends 1Mi and the light incident on each of the input ends 1Si.

[0041] The large-diameter fiber 1L, medium-diameter fiber 1M, and small-diameter fiber 1S may be arranged arbitrarily, but it is desirable to hold (arrange) the fibers in a straight line near the output ends 1Le, 1Me, and 1Se of the respective fibers. This ensures uniform illuminance at each of the output ends 1Le, 1Me, and 1Se. Furthermore, if the optical fibers are arranged in a bent manner due to the device configuration, it is preferable to bend them in the X direction (i.e., the scanning direction).

[0042] For example, the control unit CONT2 moves the semiconductor laser unit 2 using the movement mechanism 21, adjusts the output of the semiconductor laser unit 2, and so on, based on instructions from the control unit CONT1 of the exposure apparatus EX.

[0043] The multiple collector lenses (first optical elements, second optical elements) 3 are identical to one another, and a total of 27 collector lenses (first optical elements, second optical elements) 3 are provided, one for each of the six output ends 1Le, nine output ends 1Me, and twelve output ends 1Se. Each of the collector lenses 3 is provided so that its optical axis coincides or nearly coincides with the center of the core of the corresponding output end 1Le, 1Me, or 1Se, and is parallel or nearly parallel to the optical axis Ax of the illumination optical system IL1. Furthermore, each of the collector lenses 3 is provided so that the position of its front focal point coincides or nearly coincides with the position in the direction of the optical axis Ax of the light-emitting area EA1 (i.e., the plane on which the output ends 1Le, 1Me, and 1Se are arranged flush).

[0044] In this way, each collector lens 3 is arranged so that only the light beam from the corresponding exit end is incident on it. One collector lens 3 and its corresponding exit end form one light-emitting section. Each collector lens 3 has positive power.

[0045] The relay lens 4 is disposed so that the front focal point of the relay lens 4 is located on or near the plane where the rear focal points of the collector lenses 3 are located. The relay lens 4 is also disposed so that the optical axis of the relay lens 4 is parallel or nearly parallel to the optical axis Ax of the illumination optical system IL1.

[0046] The fly-eye lens 5 is an optical integrator having a plurality of lens elements (wavefront dividing elements) 5a arranged in parallel. The fly-eye lens 5 is arranged so that the entrance surface 5i is located near the rear focal point of the relay lens 4. The optical axes of the plurality of lens elements 5a are parallel to each other and are arranged so that they are each approximately parallel to the optical axis Ax of the illumination optical system IL1.

[0047] The cross-sectional shape of each lens element 5a taken along a plane perpendicular to the optical axis is a rectangle whose length is in the Y direction and whose length is in the X direction (FIG. 5C). The focal position of each entrance surface 5ai (FIG. 2) of each lens element 5a coincides or nearly coincides with the focal position of each exit surface 5ae of each lens element 5a, and the focal position of exit surface 5ae coincides or nearly coincides with the focal position of entrance surface 5ai.

[0048] The fly-eye lens 5 is composed of a large number of lens elements 5a, for example, 30 to 40 in the X direction and 8 to 12 in the Y direction, arranged closely together, and has a substantially square outer shape as a whole. In Figures 2, 5 to 7, 10, 13, 14, and 16, the number of lens elements 5a is appropriately omitted to avoid complication.

[0049] The condenser lens 6 is disposed so that the position of its front focal point coincides or nearly coincides with the position of the exit surface 5e of the fly's eye lens 5 in the direction of the optical axis Ax of the illumination optical system IL1. The condenser lens 6 is disposed so that the position of its rear focal point coincides or nearly coincides with the illuminated surface (the surface on which the mask M is disposed) in the direction of the optical axis Ax of the illumination optical system IL1. The condenser lens 6 is disposed so that the optical axis of the condenser lens 6 is parallel or nearly parallel to the optical axis Ax of the illumination optical system IL1.

[0050] The optical path of the illumination optical system IL1 having the above configuration will be described below. Here, the case where light is emitted from the output end 1Le of the large-diameter fiber 1L in the light source unit LS1 will be described as an example, but the optical path is similar when light is emitted from the output end 1Me of the medium-diameter fiber 1M or the output end 1Se of the small-diameter fiber 1S.

[0051] The light emitted from each of the multiple exit ends 1Le substantially parallel to the optical axis of the corresponding collector lens 3 (and therefore substantially parallel to the optical axis Ax of the illumination optical system IL) is collected near the rear focal position of the collector lens 3, and then, due to the action of the relay lens 4, is incident in a superimposed manner on the same region of the incident surface 5i of the fly-eye lens 5 (FIG. 2). The light emitted from each point on each of the multiple exit ends 1Le is collected on the incident surface 5i of the fly-eye lens 5 via the collector lens 3 and the relay lens 4. As a result, the multiple circular images of the multiple exit surfaces 1Le are enlarged by the collector lens 3 and the relay lens 4 and projected onto the incident surface 5i of the fly-eye lens 5 in a superimposed state.

[0052] The light from the plurality of exit ends 1Le that have been superimposed on the entrance surface 5i of the fly-eye lens 5 are then two-dimensionally split (wavefront splitting) by the numerous lens elements 5a of the fly-eye lens 5. Each of the split light beams then emerges from the exit surface 5ae of the lens elements 5a and illuminates an illumination area ILA on the illuminated surface (the surface on which the mask M is placed) in a superimposed manner via the condenser lens 6. Because the lens elements 5a of the fly-eye lens 5 are rectangular, short in the X direction and long in the Y direction, the illumination area ILA is also rectangular, short in the X direction and long in the Y direction.

[0053] In the illumination optical system IL1, a plane that serves as the Fourier transform plane of the illuminated surface (the surface on which the mask M is disposed) can be defined near the exit surface 5e of the fly-eye lens 5. This plane is defined as the illumination pupil PP of the illumination optical system IL1. The illumination pupil PP is optically conjugate with a surface on which an aperture stop (not shown) that determines the numerical aperture of the projection optical system PL is disposed. Furthermore, in the illumination optical system IL1, the illuminated surface (the surface on which the mask M is disposed) and the entrance surface 5ai of the lens element 5a of the fly-eye lens 5 are approximately conjugate. In other words, the entrance surface 5ai of the lens element 5a of the fly-eye lens 5 is enlarged and projected onto the illuminated surface at a magnification determined by the focal length of the fly-eye lens 5 and the focal length of the condenser lens 6.

[0054] [Scanning exposure using exposure apparatus EX] When using the exposure apparatus EX of this embodiment to scan and expose the image of the pattern MP formed on the mask M onto the substrate P, first the mask M on which the pattern MP is formed is placed on the mask stage MST of the exposure apparatus EX, and then the substrate P coated with photosensitive resist is placed on the substrate stage PST (Figure 1).

[0055] Next, the illumination optical system IL1 of the illumination unit IU irradiates illumination light onto five illumination areas ILA on the mask M. Of the illumination light, light that has passed through the mask M in each of the field areas A1 of the projection optical system PL is imaged onto the corresponding exposure area A2 on the substrate P via the projection optical system PL. As a result, an image of the pattern MP located within the field area A1 is formed on the substrate P located within the exposure area A2. In other words, a portion of the pattern MP is transferred to the resist layer of the substrate P. The trapezoidal shapes of the field area A1 and the exposure area A2 are determined by the shape of the field stop (not shown) of the projection optical system PL.

[0056] While irradiating illumination light from the illumination unit IU, the mask stage MST is moved to one side in the X-axis direction (scanning direction), and the substrate stage PST is moved to the other side in the X-axis direction in synchronization with this, thereby transferring a strip-shaped area extending in the X-axis direction of the pattern MP to a strip-shaped area extending in the X-axis direction of the resist layer of the substrate P (scanning exposure). After transfer of the entire area of ​​one strip-shaped area is completed, the mask stage MST is moved stepwise to one side in the Y-axis direction (non-scanning direction), and similarly, the substrate stage PST is moved stepwise to the other side in the Y-axis direction. Then, the mask stage MST and the substrate stage PST are moved synchronously in the scanning direction, and the next scanning exposure is performed.

[0057] In the region where two adjacent viewing areas A1 in the Y-axis direction overlap in the Y-axis direction (hereinafter referred to as the "overlap region OR"), the mask pattern MP is transferred to the substrate P twice: once when it is located within the end of one viewing area A1 (the portion where the width in the X-axis direction decreases toward the positive side of the Y-axis) and once when it is located within the end of the adjacent viewing area A1 (the portion where the width in the X-axis direction increases toward the positive side of the Y-axis). To avoid complicating the drawing, only one of the multiple overlap regions OR is shown shaded in Figure 1.

[0058] The total exposure amount of the resist on the substrate P during exposure of the overlapping region OR is the same as that of the other portions of the pattern MP. This is because, because the sides of the trapezoidal field of view A1 are arranged to overlap, the amount of light passing through the mask M at the edge of the field of view A1 is the same after passing through the two projection lenses. In this way, by making the field of view A1 a trapezoid and performing transfer in the overlapping region OR via two field of view areas A1 adjacent in the non-scanning direction, the pattern MP can be transferred seamlessly across the entire Y direction. Note that, in the overlapping region OR, the illumination areas ILA of the two illumination optical systems IL1 that irradiate the two field of view areas A1 with illumination light also overlap in the Y-axis direction.

[0059] [Changing Illumination Conditions] Next, changing the illumination conditions in the illumination optical system IL1 of this embodiment, specifically, changing the coherence factor (σ value) and changing the illuminance uniformity, will be described.

[0060] (1) Changing the Coherence Factor (σ Value) When the exposure apparatus EX is used to expose the pattern MP on the mask M onto the substrate P, the coherence factor (σ value) can be changed in accordance with the shape of the pattern MP. In general, it is desirable to increase the σ value for a pattern with densely packed thin lines, and decrease the σ value for an isolated pattern such as a contact hole.

[0061] The σ value is defined as "σ value = aperture stop diameter / pupil diameter of the projection optical system," or "σ value = exit-side numerical aperture of the illumination optical system / entrance-side numerical aperture of the projection optical system." Therefore, the σ value can be reduced by providing an aperture stop with a small diameter at the illumination pupil position of the illumination optical system and reducing the exit-side numerical aperture of the illumination optical system. Conversely, if an aperture stop with a large diameter is provided at the illumination pupil position, the exit-side numerical aperture of the illumination optical system will increase, and the σ value will also increase.

[0062] First, with reference to FIGS. 5A to 5C, a case where the illumination condition is set to a σ value of "large" (for example, σ=approximately 0.8 to 1.0) will be described.

[0063] In this case, first, the control unit CONT2 moves the semiconductor laser unit 2 to make the light from the semiconductor laser unit 2 incident on the large-diameter fiber group 1LG and to make the light emitted from the output ends 1Le of the large-diameter fibers 1L in the light-emitting area EA1 (FIG. 5B). The light emitted from each of the six output ends 1Le passes through the corresponding collector lens 3 and relay lens 4 and is incident in an overlapping manner on the same region of the incident surface 5i of the fly-eye lens 5.

[0064] The area ARL on the incident surface 5i (a collection of rectangular incident surfaces 5ai of the lens elements 5a) of the fly-eye lens 5, into which the light emitted from each of the six exit ends 1Le overlaps, is a circular area approximately inscribed within the approximately square outline of the incident surface 5i (Figure 5(c)).

[0065] As described above, the optical axes of the plurality of lens elements 5 a constituting the fly-eye lens 5 are parallel to one another. Therefore, the light quantity distribution of the light beam incident on the entrance surface 5 i of the fly-eye lens 5 is reflected in the light quantity distribution on the exit surface 5 e of the fly-eye lens 5, i.e., in the vicinity of the illumination pupil PP.

[0066] In this way, when light from each of the six exit surfaces 1Le illuminates a wide area of ​​the entrance surface 5i of the fly-eye lens 5, the light amount distribution at the illumination pupil PP is in a state in which the distribution spreads to positions farther away from the optical axis Ax, that is, similar to a state in which an aperture stop with a large diameter is provided at the illumination pupil PP. Therefore, the exit-side numerical aperture of the illumination optical system IL1 becomes large, and the σ value also becomes large.

[0067] Next, a case where the illumination condition is set to a σ value of "medium" (for example, σ=approximately 0.4 to 0.6) will be described with reference to FIGS. 6(a) to 6(c).

[0068] In this case, the control unit CONT2 moves the semiconductor laser unit 2 to make the light from the semiconductor laser unit 2 incident on the medium diameter fiber group 1MG and to make the light exit from the exit ends 1Me of the medium diameter fibers 1M in the light emitting area EA1 (FIG. 6B). The light emitted from each of the nine exit surfaces 1Me passes through the corresponding collector lens 3 and relay lens 4 and enters the same region of the entrance surface 5i of the fly-eye lens 5 in an overlapping manner.

[0069] The diameter of the output end 1Me of the medium-diameter fiber 1M is smaller than the diameter of the output end 1Le of the large-diameter fiber 1L. Therefore, on the incident surface 5i of the fly-eye lens 5, the area ARM where the light emitted from each of the nine output ends 1Me overlaps and enters is a circular area with a smaller diameter than the area ARL in the case of the large-diameter fiber 1L (FIG. 6C).

[0070] Therefore, the light intensity distribution at the illumination pupil PP also becomes a circular distribution with a smaller diameter than when light is emitted from the large-diameter fiber 1L, that is, similar to a state in which an aperture stop with a medium diameter is provided at the illumination pupil PP. Therefore, the exit-side numerical aperture of the illumination optical system IL1 becomes medium, and the σ value also becomes medium.

[0071] Next, a case where the illumination condition is set to a σ value of "small" (for example, σ=approximately 0.2 to 0.4) will be described with reference to FIGS. 7(a) to 7(c).

[0072] In this case, the control unit CONT2 moves the semiconductor laser unit 2 to make the light from the semiconductor laser unit 2 incident on the small diameter fiber group 1SG and to make the light exit from the exit ends 1Se of the small diameter fibers 1S in the light-emitting area EA1 (FIG. 7B). The light emitted from each of the 12 exit surfaces 1Se passes through the corresponding collector lens 3 and relay lens 4 and enters the same region of the entrance surface 5i of the fly-eye lens 5 in an overlapping manner (FIG. 7A).

[0073] The diameter of the output end 1Se of the small diameter fiber 1S is smaller than the diameter of the output end 1Me of the medium diameter fiber 1M. Therefore, on the incident surface 5i of the fly-eye lens 5, the area ARS where the light beams emitted from the 12 output ends 1Se overlap and enter is a circular area with a smaller diameter than the area ARM in the case of the medium diameter fiber 1M (FIG. 7C).

[0074] Therefore, the light intensity distribution at the illumination pupil PP also becomes a circular distribution with a smaller diameter than when light is emitted from the medium-diameter fiber 1M, that is, similar to a state in which an aperture stop with a small diameter is provided at the illumination pupil PP. Therefore, the exit-side numerical aperture of the illumination optical system IL1 becomes small, and the σ value also becomes small.

[0075] In this way, in the illumination optical system IL1 of this embodiment, the σ value can be changed by switching the exit end that emits light in the illumination area EA1 and changing the dimensions of the cross-sectional shape of the light beam at the entrance surface 5i of the fly-eye lens 5.

[0076] (2) Changing the Illuminance Distribution It is generally desirable that the illuminance of the illumination light that the illumination optical system IL makes incident on the illumination area ILA be uniform, and as an example, it is desirable that the range of illuminance unevenness be 1% or less.

[0077] In this regard, in the illumination optical system IL of this embodiment, in the light-emitting area EA1 of the light source section LS1, each of the sets of multiple output ends 1Le of the large-diameter fibers 1L, the sets of multiple output ends 1Me of the medium-diameter fibers 1M, and the sets of multiple output ends 1Se of the small-diameter fibers 1S are arranged point-symmetrically with respect to the optical axis Ax, and therefore the illuminance distribution in the illumination area ILA is highly uniform.

[0078] The reason for this will be explained with reference to Fig. 2 and Fig. 8(a). The solid line, dotted line, and dashed-dotted line in Fig. 8(a) are graphs showing the illuminance distribution in the illumination area ILA by the light beams that are emitted from the center, right, and left exit ends 1Le in Fig. 2 and pass through one lens element 5a of the fly's eye lens 5. The horizontal axis in Fig. 8(a) represents the image height, which here represents the position in the X-axis or Y-axis direction within the illumination area ILA. The vertical axis in Fig. 8(a) represents the illuminance.

[0079] According to the findings of the inventors of the present invention, the reason why the graph showing the illuminance distribution of each light beam has a mountain-like shape is the effect of spherical aberration on the entrance surface 5ai of the lens element 5a of the fly-eye lens 5. Furthermore, the reason why the illuminance distributions of the light beams emitted from the right- and left-side exit ends 1Le in Fig. 2 are shifted to the left and right with respect to the illuminance distribution of the light beam emitted from the central exit end 1Le in Fig. 2 is because the light beams emitted from each exit end 1Le in Fig. 2 are incident on the fly-eye lens 5 at an angle with respect to the optical axis Ax. The amount of shift in the illuminance distribution in the illumination area ILA depends on the magnitude of the angle of incidence of the light beams forming the illuminance distribution with respect to the fly-eye lens 5.

[0080] From this, it can be seen that if two light beams are made incident on the fly-eye lens 5 symmetrically with respect to each other with respect to the optical axis Ax, the illuminance distributions formed in the illumination area ILA by the two light beams will shift by the same amount in opposite directions with respect to the optical axis Ax. Furthermore, since the lights that are incident on the fly-eye lens 5 symmetrically with respect to each other with respect to the optical axis Ax maintain a symmetric relationship with respect to each other with respect to the optical axis Ax at any position along the optical axis Ax, it can be seen that the light sources are located in point-symmetric positions with respect to the optical axis Ax.

[0081] To summarize the above, by arranging multiple exit ends in light-emitting area EA1 in point symmetry with the optical axis Ax as the point of symmetry, multiple light beams emitted from the multiple exit ends can be made to symmetrically enter fly-eye lens 5, and multiple illuminance distributions formed in illumination area ILA by the multiple light beams emitted from the multiple exit ends can be dispersed to positions symmetric with the optical axis Ax as the point of symmetry. This allows each arch-shaped peak to be suitably dispersed, and the illuminance distribution to be uniform.

[0082] In this embodiment, based on the above-described findings of the inventors of the present invention, in the light-emitting area EA1 of the light source unit LS1, each set of multiple output ends 1Le of the large-diameter fibers 1L, each set of multiple output ends 1Me of the medium-diameter fibers 1M, and each set of multiple output ends 1Se of the small-diameter fibers 1S are arranged symmetrically with respect to the optical axis Ax. This makes it possible to uniformize the illuminance distribution in the illumination area ILA regardless of whether the σ value is set to "large," "medium," or "small."

[0083] On the other hand, the illuminance distribution may be actively changed as one of the lighting conditions.

[0084] The illumination optical system IL1 of this embodiment can change the illuminance distribution in the illumination area ILA by individually adjusting the output power of the three semiconductor lasers included in the semiconductor laser unit 2. For example, when illumination is performed under an illumination condition of σ = "large," individually adjusting the output power of the three semiconductor lasers included in the semiconductor laser unit 2 changes the balance of the light intensity emitted among the multiple light-emitting ends 1Le, thereby changing the illuminance distribution in the illumination area ILA. The same applies when illumination is performed under illumination conditions of σ = "medium" or "small." Note that the illuminance distribution can also be modified by correcting the illuminance gradient and the illuminance curvature. Regarding the illuminance distribution in FIG. 8( b), the solid line represents the illuminance distribution when the output power of the three semiconductor lasers is equal, and the dotted line represents the illuminance distribution when the output power of the semiconductor laser corresponding to the rightmost light-emitting end 1Le in FIG. 2 is increased and the output power of the semiconductor laser corresponding to the leftmost light-emitting end 1Le in FIG. 2 is decreased to correct the illuminance gradient component.

[0085] In such a modified embodiment, the exposure apparatus EX may be provided with a film thickness sensor (not shown) that measures the film thickness of the photosensitive resist applied to the substrate P. In this case, for example, the control unit CONT1 sends the measured resist film thickness to the control unit CONT2 of the illumination optical system IL1. The control unit CONT2 controls the illumination optical system IL1 based on the received film thickness information, and changes the illuminance distribution in the illumination area ILA to an appropriate distribution according to the film thickness of the resist on the substrate P that is the exposure target.

[0086] Specifically, for example, the control unit CONT2 may receive information about the unevenness in film thickness of the photosensitive resist applied to the substrate P to be exposed next from the control unit CONT1 of the exposure device before exposure, and may impart uneven illuminance to the illuminance distribution in the illumination area ILA so that the amount of exposure is greater in parts with a thicker film thickness. This makes the amount of exposure per unit volume of the resist uniform, resulting in better development results (resist images). More specifically, for example, by compensating for differences in average film thickness among multiple substrates P, line width stability can be achieved among multiple substrates P.

[0087] Alternatively, the control unit CONT2 may change the illuminance distribution according to the line width of the pattern MP on the mask M, or may change the illuminance distribution to achieve higher line width uniformity based on the results of measuring the line width uniformity of the exposed and developed resist layer. Furthermore, the change in illuminance distribution by the control unit CONT2 is not limited to being performed before exposure, but may also be performed during scanning exposure. In this case, for example, the control unit CONT1 acquires film thickness information (e.g., measured before exposure by a film thickness sensor provided in the exposure apparatus) at multiple (numerous) points on the substrate P, and sequentially changes the illuminance distribution during scanning exposure to correspond to the film thickness at the exposure target position. That is, the illumination optical system IL1 irradiates illumination light, and the illuminance distribution is changed during the period when the pattern MP is being exposed onto one substrate P via the projection optical system PL, thereby changing the exposure conditions for the substrate P to which the transfer is being performed. This, for example, can compensate for uneven resist film thickness within one substrate P and achieve line width uniformity within one substrate P.

[0088] The control unit CONT1 (or any other control unit) of the exposure apparatus EX may adjust the illuminance distribution of another illumination optical system IL1 included in the illumination unit IU by taking into consideration the illuminance distribution of a predetermined illumination optical system IL1 included in the illumination unit IU. Specifically, for example, the control unit CONT1 may change the illuminance distribution of one illumination optical system IL1 that irradiates a predetermined overlap region OR with illumination light by taking into consideration the illuminance distribution of the other illumination optical system IL1 that irradiates the overlap region OR with illumination light, so that the illumination light is appropriately irradiated in the overlap region OR.

[0089] In some cases, the photosensitivity of the resist is not proportional to the exposure amount, which is expressed as illuminance x exposure time. In such cases, if the exposure is performed in multiple steps, it may be possible to address the issue by changing the illuminance distribution to correct the illuminance.

[0090] The effects of the illumination optical system IL1 and exposure apparatus EX of this embodiment are summarized below.

[0091] The illumination optical system IL1 of this embodiment can change the size of the light beam emitted from the light source unit LS1, and therefore can change the illumination conditions (σ value) without blocking part of the light beam. In other words, the illumination conditions can be changed without causing a loss of light intensity.

[0092] In the illumination optical system IL1 of this embodiment, the size of the light beam itself emitted from the light source section LS1 can be changed, so the illumination conditions (σ value) can be changed without providing a complex structure including a moving mechanism, such as a variable diaphragm, near the illuminated surface. This is particularly advantageous when configuring an illumination unit IU that includes multiple illumination optical systems IL1, and leads to a reduction in the size of the illumination unit IU, and ultimately to a reduction in the size of the exposure apparatus EX.

[0093] The illumination optical system IL1 of this embodiment irradiates the illumination area ILA with all of the light emitted from the semiconductor laser unit 2, regardless of the σ value. Therefore, it is possible to change the σ value while maintaining a constant amount of light irradiated onto the illuminated surface. In contrast, in conventional technology, a small illumination σ is achieved by blocking the light beam with an aperture stop, which reduces the amount of light.

[0094] The illumination optical system IL1 of this embodiment can change the illuminance distribution in the illumination area ILA. Therefore, by changing the illuminance distribution in accordance with the state of the mask pattern MP or the resist coated on the substrate P, it is possible to achieve more suitable illumination conditions in accordance with the state of the mask M or the substrate P. Furthermore, in the illumination area EA1, the plurality of exit ends 1Le, the plurality of exit ends 1Me, and the plurality of exit ends 1Se are each arranged point-symmetrically with respect to the optical axis Ax, so that a highly uniform illuminance distribution can also be achieved.

[0095] The illumination optical system IL1 of this embodiment includes an optical fiber group 1, and the emission ends of the optical fibers included in the optical fiber group 1 are arranged in the light-emitting area EA1. Therefore, the semiconductor laser unit 2, which is relatively large and requires a cooling mechanism, and the moving mechanism 22, which may have a complex structure, can be provided in a location with relatively ample space away from the illumination area ILA. Furthermore, the light intensity distribution of the light emitted from the semiconductor laser unit 2 can be made uniform inside the optical fiber.

[0096] The exposure apparatus EX of the present embodiment can transfer various patterns MP of the mask M onto the substrate P satisfactorily while easily and suitably switching illumination conditions using the illumination optical system IL1.

[0097] <Modifications of First Embodiment> The following modifications can also be used in the illumination optical system IL1 of the first embodiment.

[0098] In the light source unit LS1 of the illumination optical system IL1 of the first embodiment, three types of optical fibers with different core diameters are used to switch the size of the incident area of ​​the light beam on the incident surface 5i of the fly-eye lens 5 (dimensions of the cross-sectional shape) and switch the σ value, but this is not limited to this.

[0099] Specifically, for example, in the fiber group 1, the large-diameter fiber 1L and the small-diameter fiber 1S are each replaced with a medium-diameter fiber 1M. In this case, the arrangement of the fiber end faces in the light-emitting area EA1 as viewed in the direction of the optical axis Ax is the same as the arrangement in the first embodiment ( FIG. 4 ), except that the sizes of the end faces are all the same. However, the positions of the fiber end faces in the direction of the optical axis Ax are made different from each other.

[0100] Of the 27 exit ends 1Me arranged in this manner, in the first embodiment, a collector lens 3 is used for the exit end 1Me located at the location where the exit end 1Me of the medium diameter fiber 1M is located, as in the first embodiment (Figure 9).

[0101] On the other hand, in the first embodiment, the position of the output end 1Me (left end in FIG. 9 ) located where the output end 1Le of the large-diameter fiber 1L is located is on the relay lens 4 side relative to the output end 1Me located where the output end 1Me of the medium-diameter fiber 1M is located, also in the first embodiment. The collector lens 3 is replaced with a collector lens 3L having a smaller focal length (smaller radius of curvature) than the collector lens 3. The collector lens 3L is positioned so that its front focal point is located on the corresponding output end 1Me. The diameter of the light beam emerging from the collector lens 3L is larger at the incident surface 5i of the fly-eye lens 5 than the diameter of the light beam emerging from the collector lens 3.

[0102] Similarly, in the first embodiment, the position of the output end 1Me (the right end in FIG. 9 ) located where the output end 1Se of the small diameter fiber 1S is located is set on the opposite side of the relay lens 4 from the output end 1Me located where the output end 1Me of the medium diameter fiber 1M is located, as in the first embodiment. The collector lens 3 is replaced with a collector lens 3S having a larger focal length (larger radius of curvature) than the collector lens 3. The collector lens 3S is positioned so that its front focus is located on the corresponding output end 1Me. The diameter of the light beam emerging from the collector lens 3S is smaller at the incident surface 5i of the fly's eye lens 5 than the diameter of the light beam emerging from the collector lens 3.

[0103] 9, in this modification, the rear focal points of the collector lenses 3L, 3, and 3S are made to coincide or nearly coincide with the position of the front focal point of the relay lens 4. This makes it possible to change the σ value without changing the position where the light source image is in focus.

[0104] In this modified embodiment, the focal lengths and positions of the collector lenses corresponding to the output ends of the optical fibers are made different while the core diameters of the optical fibers in the fiber group 1 are made uniform. In this modified embodiment, too, the size of the incident area (dimensions of the cross-sectional shape) of the light beam on the incident surface 5i of the fly-eye lens 5 can be changed by moving the semiconductor laser unit 2, and the magnitude of the σ value can be changed.

[0105] Although the illumination optical system IL1 of the first embodiment is configured to allow selection of three σ values, this is not a limitation. For example, the small-diameter fiber 1S may be removed from the fiber group 1, allowing selection of only two σ values. Alternatively, optical fibers with core diameters different from those of the large-diameter fiber 1L, the medium-diameter fiber 1M, and the small-diameter fiber 1S may be added to the fiber group 1, allowing selection of four or more σ values. Furthermore, although the illumination optical system IL1 of the first embodiment is configured to allow selection of three σ values, this is not a limitation. A relay optical system that zooms the diameter of the light at the fiber output end may be added between the collector lens 3 and the relay lens 4. This allows the dimensions of the cross-sectional shape of the light beam at the incident surface 5i of the fly-eye lens 5 to be changed, thereby allowing the σ value to be continuously changed. In this case, one or two types of fibers may be omitted from the large-diameter fiber 1L, the medium-diameter fiber 1M, and the small-diameter fiber 1S of the fiber group 1.

[0106] Second Embodiment An illumination optical system IL2 according to a second embodiment will be described with reference to FIGS.

[0107] The illumination optical system IL2 of the second embodiment is the same as the illumination optical system IL1 of the first embodiment, except that the configuration of the light source unit LS2 is different from that of the light source unit LS1 of the illumination optical system IL1 of the first embodiment. Explanation of the configuration that is the same as that of the first embodiment IL1 will be omitted.

[0108] [Light Source Section LS2] As shown in Figures 10 and 11, the light source section LS2 mainly includes an optical fiber (light guide) group 7, a semiconductor laser unit (light source device) 8, a plurality of collector lenses 9, and a control section (illuminance distribution control section) CONT2.

[0109] As shown in FIG. 11 , the optical fiber group 7 is composed of a normal illumination fiber group 7NG including a plurality of normal illumination fibers 7N, a ring illumination fiber group 7AG including a plurality of ring illumination fibers 7A, and a quadrupole illumination fiber group 7PG including a plurality of quadrupole illumination fibers 7P.

[0110] Each of the plurality of normal illumination fibers 7N included in the normal illumination fiber group 7NG has an incident end 7Ni to which light from the semiconductor laser unit 8 is incident and an exit end 7Ne from which the incident light is emitted. Each fiber 7N has one exit end 7Ne for one incident end 7Ni. The cross-sectional shape of the exit end 7Ne is circular (FIG. 12).

[0111] Each of the multiple annular illumination fibers 7A included in the annular illumination fiber group 7AG has an incident end 7Ai into which light from the semiconductor laser unit 8 is incident, and an exit end 7Ae from which the incident light is emitted. Each of the annular illumination fibers 7A branches into multiple fibers on a path from the incident end 7Ai to the exit end 7Ae, and at the exit end 7Ae, multiple fiber end faces, each of which is circular, are arranged in an annular shape ( FIG. 12 ).

[0112] Each of the multiple quadrupole lighting fibers 7P included in the quadrupole lighting fiber group 7PG has an incident end 7Pi into which light from the semiconductor laser unit 2 is incident and an exit end 7Pe from which the incident light is emitted. Each quadrupole lighting fiber 7P branches into four on the way from the incident end 7Pi to the exit end 7Pe, and at the exit end 7Pe, the four fiber end faces, each of which is circular, are arranged at equal intervals along the circumference ( FIG. 12 ).

[0113] To avoid complication of the drawings, only one normal illumination fiber 7N, one annular illumination fiber 7A, and one quadrupole illumination fiber 7P are shown in FIGS. 10, 13, and 14.

[0114] The output end 7Ne of each of the normal illumination fibers 7N, the output end 7Ae of each of the annular illumination fibers 7A, and the output end 7Pe of each of the quadrupole illumination fibers 7P are all configured to be planar. As shown in FIG. 12 , the output ends 7Ne, 7Ae, and 7Pe are arranged so as to be flush with one another in a plane perpendicular to the optical axis Ax of the illumination optical system IL2. Here, the planar area where the output ends 7Ne, 7Ae, and 7Pe are arranged flush with one another is referred to as the light-emitting area EA2. Note that if the focal lengths of the multiple collector lenses 9 corresponding to the output ends 7Ne, 7Ae, and 7Pe are different from one another, the positions of the output ends 7Ne, 7Ae, and 7Pe in the Z-axis direction may be different from one another. In this case, the positions of the rear foci of the multiple collector lenses 9 with different focal lengths in the direction of the optical axis Ax coincide or nearly coincide, and the positions of the front foci of each of the multiple collector lenses 9 with different focal lengths in the direction of the optical axis Ax coincide or nearly coincide with the position of one of the exit ends 7Ne, 7Ae, and 7Pe in the direction of the optical axis Ax.

[0115] In the light-emitting area EA2, the emission ends 7Ne of the normal illumination fibers 7N are arranged in a matrix of two rows in the X direction and two columns in the Y direction. In both the X direction and the Y direction, the midpoint between the two emission ends 7Ne is aligned with the optical axis Ax.

[0116] The emission ends 7Ae of the annular illumination fibers 7A are arranged in a matrix of two rows in the X direction and two columns in the Y direction, with the normal illumination fibers 7N sandwiched between them in the Y direction. In both the X and Y directions, the midpoint between the two emission ends 7Ae is aligned with the optical axis Ax.

[0117] The emission ends 7Pe of the quadrupole illumination fibers 7P are arranged in a matrix of two rows in the X direction and two columns in the Y direction, with the annular illumination fiber 7A sandwiched between them in the Y direction. In both the X and Y directions, the midpoint between the two emission ends 7Pe is aligned with the optical axis Ax.

[0118] In this way, in the light-emitting area EA2, a set of four emission ends 7Ne of the normal illumination fibers 7N, a set of four emission ends 7Ae of the annular illumination fibers 7A, and a set of four emission ends 7Pe of the quadrupole illumination fibers 7P are each arranged symmetrically with respect to the position of the optical axis Ax (the optical axis of the relay lens 4).

[0119] In this embodiment, the multiple emission ends 7Ne are arranged point-symmetrically with respect to the optical axis Ax as the reference, and are also arranged line-symmetrically with respect to a reference line that passes through the optical axis Ax and extends in the X-axis direction, and are also arranged line-symmetrically with respect to a reference line that passes through the optical axis Ax and extends in the Y-axis direction. The same applies to the multiple emission ends 7Ae and the multiple emission ends 7Pe. In this way, multiple emission ends of the same type may be arranged line-symmetrically with respect to a reference line that passes through the optical axis Ax and extends in the X-axis direction and / or a reference line that passes through the optical axis Ax and extends in the Y-axis direction, rather than point-symmetrically with respect to the optical axis Ax as the reference.

[0120] The semiconductor laser unit 8 includes four semiconductor lasers (laser diodes), and is configured so that the light beams from the semiconductor lasers are emitted parallel to each other from different positions.

[0121] The semiconductor laser unit 8 is moved by a moving mechanism 81, and causes the light beams from the four semiconductor lasers to be incident on any of the four incident ends 7Ni included in the normal illumination fiber group 7NG, the four incident ends 7Ai included in the annular illumination fiber group 7AG, or the four incident ends 7Pi included in the quadrupole illumination fiber group 7PG.

[0122] The light incident on each of the input ends 7Ni is repeatedly internally reflected within each of the normal illumination fibers 7N, and is emitted with a substantially uniform light intensity distribution from each of the output ends 7Ne arranged in the light-emitting area EA2. The same is true for the light incident on each of the output ends 7Ae and 7Pe.

[0123] A total of 12 collector lenses 9 are provided, one for each of the four output ends 7Ne, four output ends 7Ae, and four output ends 7Pe. The collector lens 9 corresponding to the output end 7Ne is provided so that its optical axis coincides or nearly coincides with the center of the core at the output end 7Ne. The collector lens 9 corresponding to the output end 7Ae is provided so that its optical axis coincides or nearly coincides with the center of the annular shape at the output end 7Ae. The collector lens 9 corresponding to the output end 7Pe is provided so that its optical axis coincides or nearly coincides with the center of the four circular output ends at the output end 7Pe. In Figure 12, the position where the two-dot chain lines intersect indicates the position of the optical axis of the collector lenses 9.

[0124] Each of the collector lenses 9 is arranged so that its optical axis is parallel or nearly parallel to the optical axis Ax of the illumination optical system IL2 (which is equal to the optical axis of the relay lens 4). Each of the collector lenses 9 is arranged so that the position of its front focal point coincides or nearly coincides with the position of the light-emitting area EA2 (i.e., the plane on which the exit ends 7Ne, 7Ae, 7Pe are arranged flush) in the direction of the optical axis Ax.

[0125] [Modified Illumination] Next, a description will be given of changing the illumination conditions in the illumination optical system IL2 of this embodiment, specifically, switching between normal illumination, annular illumination, and quadrupole illumination.

[0126] When performing normal illumination, the control unit CONT2 moves the semiconductor laser unit 2 to cause light from the semiconductor laser unit 8 to be incident on the normal illumination fiber group 7NG and to be emitted from the emission ends 7Ne of the normal illumination fibers 7N in the light-emitting area EA2 (FIG. 10(a)). The light emitted from each of the four emission ends 7Ne passes through the corresponding collector lens 9 and relay lens 4 and is incident in an overlapping manner on the same region of the entrance surface 5i of the fly-eye lens 5.

[0127] The area ARN on the incident surface 5i (a collection of rectangular incident surfaces 5ai of lens elements 5a) of the fly-eye lens 5, into which the light emitted from each of the four exit ends 7Ne overlaps, is a circular area approximately inscribed within the approximately square outline of the incident surface 5i (Figure 10(b)).

[0128] As described above, the light quantity distribution of the light beam incident on the entrance surface 5i of the fly-eye lens 5 is reflected in the light quantity distribution at the exit surface 5e of the fly-eye lens 5, so a circular pupil intensity distribution is formed in the illumination pupil PP near the exit surface 5e of the fly-eye lens 5, and normal illumination is performed.

[0129] When performing annular illumination, the control unit CONT2 moves the semiconductor laser unit 2 to cause light from the semiconductor laser unit 8 to enter the annular illumination fiber group 7AG and exit from the exit ends 7Ae of the annular illumination fibers 7A in the light-emitting area EA2 (FIG. 13(a)). The light emitted from each of the four exit ends 7Ae passes through the corresponding collector lens 9 and relay lens 4 and enters the same region of the entrance surface 5i of the fly's eye lens 5 in an overlapping manner.

[0130] The area ARA on the entrance surface 5i of the fly-eye lens 5, onto which the light emitted from each of the four exit surfaces 7Ae overlaps, is a circular area that is approximately inscribed within the substantially square outline of the entrance surface 5i (FIG. 13(b)). Therefore, a circular pupil intensity distribution is formed in the illumination pupil PP near the exit surface 5e of the fly-eye lens 5, and annular illumination is performed.

[0131] When quadrupole illumination is performed, the control unit CONT2 moves the semiconductor laser unit 2 to cause light from the semiconductor laser unit 8 to enter the quadrupole illumination fiber group 7PG and exit from the exit ends 7Pe of the quadrupole illumination fibers 7P in the light-emitting area EA2 (FIG. 14(a)). The light emitted from each of the four exit surfaces 7Pe passes through the corresponding collector lens 9 and relay lens 4 and enters the same region of the entrance surface 5i of the fly-eye lens 5 in an overlapping manner.

[0132] The area ARP on the entrance surface 5i of the fly-eye lens 5, into which the light beams emitted from each of the four exit surfaces 7Pe overlap, is four circular areas positioned at equal intervals in the circumferential direction around the optical axis Ax (FIG. 14B). Therefore, a quadrupole-shaped pupil intensity distribution is formed in the illumination pupil PP near the exit surface 5e of the fly-eye lens 5, and quadrupole illumination is performed.

[0133] In this way, in the illumination optical system IL2 of this embodiment, by switching the exit end that emits light in the illumination area EA2 and changing the cross-sectional shape of the light beam at the entrance surface 5i of the fly-eye lens 5, it is possible to change the illumination conditions, i.e., switch between normal illumination, annular illumination, and quadrupole illumination.

[0134] Like the illumination optical system IL1 of the first embodiment, the illumination optical system IL2 of this embodiment can change the illuminance distribution in the illumination area ILA by individually adjusting the outputs of the four semiconductor lasers provided in the semiconductor laser unit 8 and changing the balance of the light intensity between the multiple emission ends 7Ne, the multiple emission ends 7Ae, or the multiple emission ends 7Pe. The illumination optical system IL2 of this embodiment can also be used together with a film thickness sensor of the exposure apparatus EX. In this case, for example, the control unit CONT1 sends the measured resist film thickness to the control unit CONT2 of the illumination optical system IL2. The control unit CONT2 controls the illumination optical system IL2 based on the received film thickness information and changes the illuminance distribution in the illumination area ILA to an appropriate distribution corresponding to the film thickness of the resist on the substrate P to be exposed.

[0135] The effects of the illumination optical system IL2 of this embodiment are summarized below.

[0136] In the illumination optical system IL2 of this embodiment, similar to the illumination optical system IL1 of the first embodiment, it is possible to change the illumination conditions without causing a loss of light intensity and without providing a complex structure including a moving mechanism near the illuminated surface. Furthermore, it is possible to switch between normal illumination, annular illumination, and quadrupole illumination while maintaining a constant amount of light irradiated onto the illuminated surface.

[0137] Furthermore, similar to the illumination optical system IL1 of the first embodiment, the illuminance distribution can be changed to achieve more suitable illumination conditions according to the state of the mask M and substrate P, and a highly uniform illuminance distribution can also be achieved.

[0138] <Modification of Second Embodiment> The following modification can also be used in the illumination optical system IL2 of the second embodiment.

[0139] In the light source section LS2 of the illumination optical system IL2 in the second embodiment, annular illumination is performed using the annular illumination fiber 7A, but the present invention is not limited to this.

[0140] 15, the annular illumination fiber 7A is replaced with an optical fiber 7A' that has no branches and has a single circular entrance end and a single circular exit end, similar to the normal illumination fiber 7N. Then, a first relay lens 91, a second relay lens 92, and an axicon lens 93 are arranged after the exit end 7Ae' of the optical fiber 7A' and the collector lens 9.

[0141] The condenser lens 9 is disposed so that its optical axis is parallel or nearly parallel to the optical axis Ax and its front focal point is located on or near the output end 7Ae'. The first relay lens 91, the axicon lens 93, and the second relay lens 92 are disposed on a nearly straight line so that their optical axes are parallel or nearly parallel to the optical axis Ax. Furthermore, the front focal position of the first relay lens 91 is disposed near the rear focal position of the collector lens 9, and an image of the fiber output end 7Ae' is formed near the axicon lens 93.

[0142] In this configuration, the cross-sectional shape of the light emitted from the output end 7Ae' of the optical fiber 7A' is converted to an annular shape via the collector lens 9, the first relay lens 91, and the axicon lens 93. Then, the light passes through the second relay lens 92 and the relay lens 4 and enters the annular area ARA on the entrance surface 5i of the fly-eye lens 5.

[0143] Although the illumination optical system IL2 of the second embodiment is configured to be able to switch illumination conditions among normal illumination, annular illumination, and quadrupole illumination, the present invention is not limited to this. For example, the quadrupole illumination fiber 7P may be removed from the fiber group 7, so that only two types of illumination, normal illumination and annular illumination, are selectable. Alternatively, a dipole illumination fiber may be added to the fiber group 7, so that dipole illumination can also be selected. In other words, the illumination optical system IL2 of the second embodiment can be configured in various ways so that multiple types of illumination conditions can be selected.

[0144] <Modifications of the First and Second Embodiments> The following modifications can also be used in the illumination optical system IL1 of the first embodiment and the illumination optical system IL2 of the second embodiment.

[0145] An illumination optical system that can select any illumination condition can be configured by arbitrarily combining the illumination optical system IL1 of the first embodiment and the illumination optical system IL2 of the second embodiment. Specifically, for example, the medium diameter fiber group 1MG of the illumination optical system IL1 can be replaced with the annular illumination fiber group 7AG of the illumination optical system IL2, thereby configuring an illumination optical system that can switch the illumination condition between a "large" σ value, a "small" σ value, and annular illumination.

[0146] The illumination optical systems IL1 and IL2 of the first and second embodiments are configured so that the images of the exit ends of the optical fibers arranged in the light-emitting areas EA1 and EA2 are formed near the incident surface 5i of the fly-eye lens 5. However, this is not limiting, and the images of the exit ends of the optical fibers arranged in the light-emitting areas EA1 and EA2 may be formed near the exit surface 5e of the fly-eye lens 5. Specifically, such an optical system may have a configuration in which an additional relay lens 4' is added between the collector lens 3 and the relay lens 4 ( FIG. 16 ).

[0147] In the illumination optical system IL1 having such a configuration, the σ value can also be changed by switching the exit end that emits light in the illumination area EA1 and changing the dimensions of the cross-sectional shape of the light beam at the incident surface 5i of the fly-eye lens 5. In the illumination optical system IL2 having such a configuration, the illumination conditions can also be changed, that is, switched between normal illumination, annular illumination, and quadrupole illumination, by switching the exit end that emits light in the illumination area EA2 and changing the cross-sectional shape of the light beam at the incident surface 5i of the fly-eye lens 5. In the case of quadrupole illumination, it is also possible to insert a diffractive optical element or the like between the collector lens 3 and the relay lens 4.

[0148] In the illumination optical systems IL1 and IL2 of the first and second embodiments, the illuminance distribution in the illumination area ILA is changed by changing the output balance of the multiple semiconductor lasers provided in the semiconductor laser units 2 and 8, but this is not limited to this.

[0149] Specifically, for example, an optical fiber is added to at least one of the large-diameter fiber group 1LG, medium-diameter fiber group 1MG, and small-diameter fiber group 1SG included in fiber group 1, and the normal illumination fiber group 7NG, annular illumination fiber group 7AG, and quadrupole illumination fiber group 7PG included in fiber group 7, thereby increasing the number of optical fibers constituting the fiber group. The incident ends of the added optical fibers are arranged at positions where light from the semiconductor laser unit 2 can be incident by moving the semiconductor laser unit 2. The output ends of the added optical fibers are arranged in gaps between the existing output ends in the illumination areas EA1 and EA2. Specifically, for example, an additional large-diameter fiber 1L is provided in the large-diameter fiber group 1LG of the first embodiment, and its output end 1Le is arranged at a position different from the output end 1Le shown in FIG.

[0150] As a result, a fiber group with an increased number of optical fibers has an additional optical fiber. This means that, for example, in the case of the large-diameter fiber group 1LG, by changing the incident end into which light is incident of the semiconductor laser unit 2 from the incident end 1Li shown in FIG. 3 to the incident end 1Li of the additional large-diameter fiber 1L, the output end from which light is output in the illumination area EA1 can be changed from the output end 1Le shown in FIG. 3 to the output end 1Le of the additional large-diameter fiber 1L.

[0151] Since the light from the output end 1Le of the added large-diameter fiber 1L is emitted from a position on the light-emitting areas EA1 and EA2 that is different from the existing output end (i.e., the output end 1Le shown in FIG. 4), it is incident on the incident surface 5i of the fly-eye lens 5 at a different angle from the light from the existing output end, and forms an illuminance distribution in the illumination area ILA that is different from the light from the existing output end. Therefore, the control unit CONT2 can change the input end to which light is incident of the semiconductor laser unit 2 between the input ends 1Li and change the position of the output end 1Le that emits light in the illumination area EA1, thereby changing the illuminance distribution in the illumination area ILA. Note that, because the switching is within the large-diameter fiber group 1LG, the illumination condition of σ value = "large" is maintained.

[0152] Here, the case where an additional optical fiber is provided in the large diameter fiber group 1LG has been described as an example, but similar modifications can also be made in other fiber groups such as the medium diameter fiber group 1MG.

[0153] As another method for changing the illuminance distribution in the illumination area ILA, an arbitrary moving mechanism may be provided to move at least one of the exit ends 1Le, 1Me, and 1Se arranged in the light-emitting area EA1 in the X and Y directions together with the corresponding collector lens 3. Also, an arbitrary moving mechanism may be provided to move at least one of the exit ends 7Ne, 7Ae, and 7Pe arranged in the light-emitting area EA2 in the X and Y directions together with the corresponding collector lens 9.

[0154] In this configuration, by moving a pair of collector lenses corresponding to at least one of the exit ends of the light-emitting areas EA1 and EA2 relative to the optical axis Ax of the illumination optical systems IL1 and IL2, the angle of incidence with respect to the fly-eye lens 5 is changed, and the illuminance distribution of the illumination area ILA is changed.

[0155] As another method for changing the illuminance distribution in the illumination area ILA, a configuration in which the optical axis of at least one of the collector lenses 3 is offset (decentered) from the center of the core of the corresponding output end 1Le, 1Me, or 1Se can be used. In this configuration, the output end, which is positioned eccentrically with respect to the optical axis of the collector lens 3, can be rotated about the optical axis of the collector lens 3 to change the angle of incidence of the light passing through the collector lens 3 with respect to the incident surface 5i of the fly-eye lens 5. Alternatively, by providing an arbitrary movement mechanism that changes the positional relationship between the collector lenses 3, 9 and the corresponding output end and moving at least one of the collector lenses 3, 9 and the corresponding output end in a direction perpendicular to the optical axis of the collector lenses 3, 9, the angle of incidence of the light passing through the collector lenses 3, 9 with respect to the fly-eye lens 5 can be changed, thereby changing the illuminance distribution in the illumination area ILA.

[0156] As another method for changing the illuminance distribution in the illumination area ILA, a bending mechanism is provided that changes the curvature of the optical fiber (physically bends it), and the curvature of at least one of the large-diameter fiber 1L, the medium-diameter fiber 1M, and the small-diameter fiber 1S included in the fiber group 1, or the normal illumination fiber 7N, the annular illumination fiber 7A, and the quadrupole illumination fiber 7P included in the fiber group 7 is changed near the output end, thereby changing the angle of incidence of the light that has passed through the corresponding collector lenses 3 and 9 with respect to the fly-eye lens 5, and changing the illuminance distribution in the illumination area ILA.

[0157] In the conventional method for changing the incident angle distribution in the illumination area ILA, the illumination system aperture stop located at the pupil conjugate plane PP was moved in a direction perpendicular to the optical axis. However, since the above embodiment does not have an illumination system aperture stop, such adjustment is difficult. Therefore, any movement mechanism may be used to tilt the entire light source units LS1 and LS2 in the X or Y direction relative to the relay lens 4. Alternatively, a prism pair (a Dove prism pair or a wedge prism pair) may be disposed between the light source units LS1 and LS2 and the relay lens 4, and the relative positions of the prisms constituting the prism pair may be changed to change the direction of the light emitted from the light source units LS1 and LS2, thereby shifting the position of the light beam entering the fly-eye lens 5, thereby changing the light intensity distribution at the exit end of the fly-eye lens 5 and changing the incident angle distribution incident on the illumination area ILA.

[0158] In the illumination optical systems IL1 and IL2 of the first and second embodiments, the fiber group onto which light is incident is switched by moving the semiconductor laser units 2 and 8 using the moving mechanisms 21 and 81, but this is not limiting. One semiconductor laser unit may be provided for each of a plurality of fiber groups, such as the large-diameter fiber group 1LG, and light may be incident on the desired fiber group by switching the semiconductor laser unit 2 to be operated.

[0159] In the illumination optical system IL1 of the first embodiment and the illumination optical system IL2 of the second embodiment, a light-emitting diode unit including a plurality of light-emitting diodes (LEDs) may be used instead of the semiconductor laser unit 2, 8. The light-emitting diode unit may be configured to be moved by a moving mechanism 21, 81 and to direct light to a desired fiber group among a plurality of fiber groups such as the large-diameter fiber group 1LG. Alternatively, a light-emitting diode may be provided individually for each fiber of a plurality of fiber groups such as the large-diameter fiber group 1LG, and light may be directed to a desired fiber group by switching the light-emitting diode that emits light.

[0160] In addition, instead of the semiconductor laser units 2 and 8, a unit having a plurality of desired light sources such as fiber lasers, mercury lamps, etc. may be used.

[0161] In the illumination optical system IL1 of the first embodiment and the illumination optical system IL2 of the second embodiment, an input lens that allows light from the light source unit to enter each fiber may be provided between a light source unit such as the semiconductor laser unit 2 and the incident end of each of the optical fibers in the fiber group 1. It is also desirable to configure each of the optical fibers in the fiber group 1 so that the numerical apertures at the incident ends are the same.

[0162] In the illumination optical systems IL1 and IL2 of the first and second embodiments, the fiber group 1 may be omitted, and light-emitting diodes (an example of a solid-state light source) having light-emitting surfaces with the same shapes as the light-emitting ends 1Le and 1Ne of the light-emitting areas EA1 and EA2 may be disposed at the positions where the light-emitting ends 1Le and 1Ne of the light-emitting areas EA1 and EA2 are disposed, as shown in FIGS. 4 and 12 . In this configuration, by switching the light-emitting diodes that emit light in the light-emitting areas EA1 and EA2, the shapes of the light-emitting surfaces in the light-emitting areas EA1 and EA2 can be changed, thereby changing the shape of the image of the light-emitting surfaces projected onto the incident surface 5i of the fly-eye lens 5. Similarly, the light-emitting surfaces of semiconductor lasers (an example of a solid-state light source) may be disposed in the light-emitting areas EA1 and EA2. In this configuration, the light-emitting surfaces of the light-emitting diodes and semiconductor lasers correspond to the "light-emitting surfaces" of the present invention.

[0163] The illumination optical system IL1 of the first embodiment has six exit ends 1Le for realizing the illumination condition of σ="large," nine exit ends 1Me for realizing the illumination condition of σ="medium," and twelve exit ends 1Se for realizing the illumination condition of σ="small." The illumination optical system IL2 of the second embodiment realizes each illumination condition using four exit ends. However, the number of light-emitting surfaces required to realize each illumination condition is arbitrary, and may be only one.

[0164] In the illumination optical systems IL1 and IL2 of the first and second embodiments, the semiconductor laser units 2 and 8 are moved under the control of the control unit CONT2 to switch the illumination conditions, but this is not limiting. Specifically, for example, the semiconductor laser units 2 and 8 may be manually moved to switch the illumination conditions.

[0165] 4 and 12, rectangular contour lines OL1 and OL2 centered on the optical axis Ax are formed by projecting the rectangular contour of the exit surface 5ae of the lens element 5a of the fly-eye lens 5 by the relay lens 4 and the fly-eye lens 5. Light emitted from the collector lenses 3 and 9 outside the contour lines OL1 and OL2 is bent significantly and emitted from a different (for example, adjacent) lens element 5a than the light emitted from the collector lenses 3 and 9 inside the contour lines OL1 and OL2, and does not reach the illumination area ILA. Therefore, it is desirable to arrange the exit ends of the light-emitting areas EA1 and EA2 and the collector lenses 3 and 9 so that the light from the collector lenses 3 and 9 is located inside the contour lines OL1 and OL2.

[0166] The arrangement of the multiple emission ends 1Le, 1Me, and 1Se in the light-emitting area EA1 may be such that, when two light-emitting areas EA1 are adjacent to each other in the Y or X direction with their short or long sides of the outline OL1 overlapping, the overall arrangement is point-symmetric with the center of the overlapping short or long side as the symmetry point, and / or line-symmetric with the overlapping short or long side as the reference line. This makes it possible to make the illuminance distribution in the illumination area ILA more uniform. The same applies to the multiple emission ends 7Ne, 7Ae, and 7Pe in the light-emitting area EA2.

[0167] The illumination optical systems IL1 and IL2 of the first and second embodiments may be provided with alignment LEDs that emit alignment light in the light-emitting areas EA1 and EA2. The alignment light can be used when aligning the mask M and substrate P in the exposure apparatus EX. This configuration makes it possible to provide alignment light with a small amount of light that is suitable for alignment. In addition, the light-emitting areas EA1 and EA2 may be provided with a desired light source that emits light for a desired purpose other than the exposure light that is irradiated onto the illumination area ILA.

[0168] In the illumination optical systems IL1 and IL2 of the first and second embodiments, lenses such as the collector lens 3, relay lens 4, and condenser lens 6 are not limited to single lenses, but may be lens groups or lens systems composed of multiple lenses. Furthermore, they are not limited to refractive optical elements such as lenses, but may be diffractive optical elements that diffract light or reflective optical elements that reflect light. In this specification and the appended claims, the terms "collector lens," "relay lens," "condenser lens," and "optical element" refer to these various types of optical elements or combinations thereof. The relay lens 4 may be omitted as appropriate.

[0169] In the illumination optical systems IL1 and IL2 of the first and second embodiments, the fly-eye lens 5 has a plurality of lens elements 5a arranged in parallel, but these plurality of lens elements 5a may also be provided integrally.

[0170] In the illumination optical systems IL1 and IL2 of the first and second embodiments, an aperture stop or a variable aperture stop may be provided at the position of the illumination pupil PP. The variable aperture stop is used in a manner that minimizes loss of light quantity in order to assist in switching illumination conditions by switching light-emitting surfaces.

[0171] The illumination optical systems IL1 and IL2 of the first and second embodiments may be used as the illumination optical systems of an exposure apparatus equipped with only a single projection optical system, rather than as the illumination optical systems of a so-called multi-lens type exposure apparatus EX equipped with multiple projection optical systems PL.Furthermore, the illumination optical systems IL1 and IL2 of the first and second embodiments may be used as the illumination optical systems of a step-and-repeat type exposure apparatus (a so-called stepper).

[0172] The exposure apparatus EX of the first and second embodiments is manufactured by assembling various subsystems, including the components recited in the accompanying claims, so as to maintain predetermined mechanical, electrical, and optical precision. To ensure these various precisions, adjustments are made before and after assembly to achieve optical precision for the various optical systems, mechanical precision for the various mechanical systems, and electrical precision for the various electrical systems. The process of assembling the various subsystems into the exposure apparatus EX includes mechanical connections between the various subsystems, wiring connections for electrical circuits, and piping connections for air pressure circuits. It goes without saying that each subsystem is individually assembled before the process of assembling the various subsystems into the exposure apparatus EX. After the process of assembling the various subsystems into the exposure apparatus EX is complete, comprehensive adjustments are made to ensure the various precisions of the exposure apparatus EX as a whole. The manufacture of the exposure apparatus EX may be performed in a clean room where temperature, cleanliness, etc. are controlled.

[0173] A device manufacturing method using the illumination optical systems IL1 and IL2 and exposure apparatus EX of the first and second embodiments will be described.

[0174] As shown in Figure 17, the device manufacturing method for manufacturing semiconductor devices and liquid crystal display elements includes a film formation process S40 in which a thin film having predetermined physical properties is formed on a substrate P that will be the substrate for the semiconductor device, a coating process S42 in which a photoresist (resist), which is a photosensitive material, is applied to the formed thin film, an exposure process S44 in which a pattern MP formed on a mask M is exposed (transferred) onto the substrate P coated with the photoresist using an exposure apparatus EX, and a development process S46 in which the substrate P after exposure (transfer) is developed, i.e., the photoresist to which the pattern MP has been transferred is developed.

[0175] The device manufacturing method further includes a processing step S48 in which the surface of the substrate P is processed using the resist pattern generated on the surface of the substrate P in the development step S46 as a mask. Here, the resist pattern refers to a photoresist layer in which concaves and convexes corresponding to the pattern transferred by the exposure apparatus EX are generated, and the concaves penetrate the photoresist layer. In the processing step S48, the surface of the substrate P is processed via the resist pattern. The processing includes, for example, etching the surface of the substrate P and depositing a film of metal, semiconductor material, dielectric material, or the like on the surface of the substrate P, and this step is repeated multiple times.

[0176] 18 , the manufacturing process for a liquid crystal device such as a liquid crystal display element includes a pattern formation process S50, a color filter formation process S52, a cell assembly process S54, and a module assembly process S56. In the pattern formation process S50, the exposure apparatus EX of the above embodiment is used to form a predetermined pattern such as a circuit pattern or an electrode pattern on a glass substrate coated with photoresist. The pattern formation process S50 includes an exposure process similar to the exposure process S44 described above, i.e., a process of exposing (transferring) a predetermined pattern such as a circuit pattern formed on a mask onto the glass substrate using the exposure apparatus EX, as well as a development process and a processing process similar to the development process S46 and processing process S48 described above.

[0177] In the color filter formation process S52, multiple sets of three dots corresponding to R (Red), G (Green), and B (Blue) are arranged in a matrix. Alternatively, a color filter is formed by arranging multiple sets of R, G, and B stripe filters in the horizontal scanning direction. In the cell assembly process S54, a liquid crystal panel (liquid crystal cell) is assembled using a glass substrate on which a predetermined pattern has been formed in the pattern formation process S50 and a color filter formed in the color filter formation process S52. Specifically, the liquid crystal panel is formed by injecting liquid crystal between the glass substrate and the color filter. In the module assembly process S56, various components such as an electrical circuit and a backlight for display operation are attached to the liquid crystal panel assembled in the cell assembly process S54.

[0178] The illumination optical systems IL1 and IL2 of the first and second embodiments are not limited to application to exposure apparatuses for manufacturing semiconductor devices, but can also be widely applied to, for example, exposure apparatuses for display devices such as liquid crystal display elements formed on rectangular glass plates or sheet-like flexible bodies, or electroluminescence, and exposure apparatuses for manufacturing various devices such as image pickup elements (CCDs, etc.), micromachines, thin-film magnetic heads, and DNA chips. Furthermore, the illumination optical systems IL1 and IL2 of the first and second embodiments can also be applied to exposure processes (exposure apparatuses) when manufacturing masks (photomasks, reticles, etc.) on which mask patterns for various devices are formed using a photolithography process.

[0179] According to an illumination optical system of one aspect of the present invention, illumination conditions can be switched while suppressing loss of light quantity, and exposure can be suitably performed in the manufacture of various devices.

[0180] 1, 7 Fiber group 1L Large diameter fiber 1M Medium diameter fiber 1S Small diameter fiber 7N Fiber for normal illumination 7A Fiber for annular illumination 7P Fiber for quadrupole illumination 2, 8 Semiconductor laser unit 3, 9 Collector lens 93 Axicon lens 4 Relay lens 5 Fly-eye lens 6 Condenser lens CONT1, CONT2 Control unit EX Exposure device IL1, IL2 Illumination optical system IU Illumination unit LS1, LS2 Light source unit PL Projection optical system

Claims

1. An illumination optical system that illuminates an illuminated surface, a light source unit; a fly-eye lens disposed in an optical path between the light source unit and the illuminated surface; a condenser lens that superimposes the plurality of light beams from the fly-eye lens on the illuminated surface, The light source unit is a first light emitting unit having a first light emitting surface and a first optical element, and configured to emit a first light flux emitted from the first light emitting surface via the first optical element; a second light emitting unit having a second light emitting surface and a second optical element, and emitting the second light flux emitted from the second light emitting surface via the second optical element; The light source is configured to selectively emit a first light beam from the first light-emitting unit or a second light beam from the second light-emitting unit, an illumination optical system configured such that the cross-sectional shape or dimensions of the second light beam at the incident surface of the fly-eye lens are different from the cross-sectional shape or dimensions of the first light beam at the incident surface of the fly-eye lens;

2. 2. The illumination optical system according to claim 1, wherein the second light emitting section is configured so that a cross-sectional shape of the second light beam at the incident surface of the fly-eye lens is different from a cross-sectional shape of the first light beam at the incident surface of the fly-eye lens.

3. 3. The illumination optical system according to claim 2, wherein the shape of the second light-emitting surface is different from the shape of the first light-emitting surface.

4. 3. The illumination optical system according to claim 2, wherein the second light-emitting unit has an axicon lens disposed in an optical path between the second light-emitting surface and the second optical element.

5. 2. The illumination optical system according to claim 1, wherein the second light-emitting unit is configured so that a cross section of the second light flux at the incident surface of the fly-eye lens has the same shape as, but different dimensions from, a cross section of the first light flux at the incident surface of the fly-eye lens.

6. 6. The illumination optical system according to claim 5, wherein the second light-emitting surface has the same shape as the first light-emitting surface but different dimensions from the first light-emitting surface.

7. 6. The illumination optical system according to claim 5, wherein the first optical element is a focusing optical element having a first focal length and is arranged so that a front focal point of the first optical element is located on the first light-emitting surface, and the second optical element is a focusing optical element having a second focal length different from the first focal length and is arranged so that a front focal point of the second optical element is located on the second light-emitting surface.

8. the first light-emitting unit includes a plurality of pairs of a first light-emitting surface and a first optical element, and emits a first light flux from each pair; The illumination optical system according to claim 1 , further comprising a relay lens that causes the first light beams from the light-emitting portions to overlap on the incident surface of the fly-eye lens.

9. the second light-emitting unit includes a plurality of pairs of a second light-emitting surface and a second optical element, and emits the second light flux from each pair; The illumination optical system according to claim 8 , wherein the relay lens causes the second light beams from the light emitting portions to overlap each other on the incident surface of the fly-eye lens.

10. the light source unit further includes an illuminance distribution control unit that changes the illuminance distribution in the irradiated unit, 9. The illumination optical system according to claim 8, wherein the illuminance distribution control unit changes the illuminance distribution at the irradiated portion by changing the amount of light of the first light flux emitted from at least one of the plurality of light-emitting units and / or by switching the light-emitting unit that emits the first light flux among the plurality of light-emitting units.

11. 9. The illumination optical system according to claim 8, wherein the plurality of light-emitting portions of the first light-emitting portion are arranged in a plane perpendicular to the optical axis of the illumination optical system in point symmetry with the position of the optical axis as the point of symmetry, and / or in line symmetry with a straight line passing through the position of the optical axis as a reference line in a plane perpendicular to the optical axis.

12. a plurality of light-emitting units of the first light-emitting unit are arranged in a plane perpendicular to the optical axis of the illumination optical system, 9. The illumination optical system according to claim 8, wherein the plurality of light-emitting units are arranged so that, for any light beam included in the plurality of first light beams that are emitted from the plurality of light-emitting units and incident on the incident surface of the fly-eye lens, there exists an opposing light beam that is opposing the light beam across a straight line passing through the position of the optical axis of the illumination optical system and / or in a plane perpendicular to the optical axis, and the incident angle of the light beam with respect to the incident surface of the fly-eye lens is equal to the incident angle of the opposing light beam with respect to the incident surface of the fly-eye lens.

13. The light source unit is The optical fiber further includes a light source device, and a first light guide and a second light guide that propagate light emitted from the light source device, 13. The illumination optical system according to claim 1, wherein the first light emitting surface is an exit end of the first light guide, and the second light emitting surface is an exit end of the second light guide.

14. 14. The illumination optical system according to claim 13, further comprising a movement mechanism that moves the light source device between a first position where the light source device emits light toward an incident end of a first light guide and a second position where the light source device emits light toward an incident end of a second light guide.

15. The light source unit includes a first solid-state light source and a second solid-state light source, The illumination optical system according to claim 1, wherein the first light-emitting surface is the light-emitting surface of the first solid-state light source, and the second light-emitting surface is the light-emitting surface of the second solid-state light source.

16. An exposure apparatus comprising: the illumination optical system according to any one of claims 1 to 12 and 15 for illuminating the irradiated surface; a projection optical system for irradiating the substrate with light from the irradiated surface.

17. An exposure apparatus comprising: the illumination optical system according to claim 13 for illuminating the irradiated surface; a projection optical system for irradiating the substrate with light from the irradiated surface.

18. An exposure apparatus for performing scanning exposure of a pattern on a substrate, comprising: a plurality of illumination optical systems according to any one of claims 8 to 12 for illuminating the pattern; a plurality of projection optical systems for forming an image of the pattern on the substrate; a control unit for controlling the scanning exposure, wherein the plurality of illumination optical systems include a first illumination optical system for irradiating illumination light onto a first illumination region and a second illumination optical system for irradiating illumination light onto a second illumination region, the first illumination region and the second illumination region overlap in a non-scanning direction orthogonal to the scanning direction in which the exposure apparatus performs scanning exposure, the control unit is configured to change the illuminance distribution of the second illumination optical system based on the illuminance distribution of the first illumination optical system.

19. Exposing a pattern on the substrate using the exposure apparatus according to claim 16; developing the substrate on which the pattern has been exposed to form a mask layer having a shape corresponding to the pattern on the surface of the substrate; and processing the surface of the substrate through the mask layer.