JPH08288205A - Illumination optical system and projection aligner provided with the illumination optical system - Google Patents

Abstract

PURPOSE: To provide an illumination optical system in which the flexibility of a light guide is high and which is hardly damaged by the movement of its radiant end and a projection aligner equipped with the illumination optical system. CONSTITUTION: Radiant light from a light source 1 is condensed by an oval-shaped mirror 2, a light-source image is formed in a second focal position, the light is then converted into a parallel luminous flux by an input lens 3, the luminous flux is divided by a fly eye lens 4, a plurality of two-dimensional light sources are formed, the luminous flux which has passed an aperture diaphragm 5 and a condensing lens 6 is reflected by a mirror 7, a reticule 8 is illuminated, and an exposure illumination optical system is constituted. The light which has been transmitted through the reticle transfers a pattern to a wafer 11 by a projection optical system 10. On the other hand, a shutter 14 which can be inserted and removed freely is installed between the light source 1 and the lens 3, the light from a light-source image is taken out to the outside of the optical path of an illumination optical system in the position of the light-source image by oval-shaped mirror 2, and the light-source image is formed at a light-guide incident end 17a by a lens system 16. In a light guide 17, many optical fibers are bundled, and moving radiant end sides 17b, 17c are branched so as to become bundles whose density is lower than that of the side of the incident end.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination optical system and a projection exposure apparatus having the illumination optical system, and more particularly to an alignment illumination optical system for illuminating a reference mark on a movable stage for a photosensitive substrate of the projection exposure apparatus.

[0002]

2. Description of the Related Art In a projection exposure apparatus that sequentially exposes a pattern formed on a projection original plate such as a reticle (or mask) onto each exposure area on a photosensitive substrate such as a wafer,
It is necessary to perform relative alignment, that is, alignment between the reticle and the wafer. For this reason, the projection exposure apparatus includes an alignment illumination optical system for illuminating a translucent alignment mark (reference light) formed on the wafer movable stage, for example.

The light from the illuminated alignment mark is projected via the projection optical system, for example, by superimposing the image of the alignment mark on the reticle mark formed on the reticle. In this way, the alignment between the reticle and the wafer is performed based on the positional relationship between the reticle mark and the image of the alignment mark.

As described above, in the illumination optical system for illuminating a movable target object such as an alignment mark formed on the wafer stage, a so-called so-called "movable target object" can be illuminated so as to follow the movement of the movable target object. It is necessary to have a degree of freedom in light transmission. Therefore, a conventional illumination optical system for illuminating a movable target uses a light guide configured by bundling a large number of optical fibers. FIG. 5 is a diagram schematically showing a configuration of a conventional illumination optical system for illuminating such a movable target.

In the illumination optical system shown in FIG. 5, light emitted from a light source such as a mercury lamp 51 positioned at the first focal position of the elliptic mirror 52 is condensed by the elliptic mirror 52. The light condensed by the elliptic mirror 52 forms a light source image at the second focal position of the elliptic mirror 52.

The light from the light source image forms a light source image having a sufficient numerical aperture (NA) and diameter at the incident end 54a of the light guide 54 formed by bundling a large number of optical fibers through the lens system 53. To do. Thus, the light incident on the incident end 54a of the light guide 54 is propagated to the emitting end 54b. The light flux from the exit end 54b of the light guide 54 is converted into a parallel light flux via the condenser lens 55, and an illumination field 56 having an appropriate illumination NA is formed by Koehler illumination.

At this time, the required diameter of the optical fiber bundle of the light guide 54 is defined by the illumination NA and the focal length of the condenser lens 55. In a general light guide configured by bundling a large number of optical fibers, a large number of optical fibers are bundled at a high density, that is, at a high filling rate, from the entrance end to the exit end. Therefore, it can be considered that a secondary light source having a required effective diameter and NA is formed at the exit end 54b of the light guide 54. As described above, in order to illuminate a movable target (not shown), the exit end 54b side of the light guide 54 and the condenser lens 55 are movable.

Further, in many cases, the light guide is constituted by a large number of randomly bundled optical fibers so that the light amount distribution of the light source image formed at the exit end of the light guide becomes substantially uniform. As described above, by using the random-mix type light guide, it is possible to obtain a stable illumination field with good light efficiency. Further, in the case of forming a plurality of illumination fields, a light guide having a multi-branched emission end side and a plurality of condenser lenses corresponding to the respective emission ends may be used in combination.

[0009]

However, the illumination N
Depending on conditions such as A, the size of the illumination field, and the focal length of the condenser lens, it is necessary to increase the effective diameter of the secondary light source at the light guide emission end. By the way, in the conventional illumination optical system as described above, a light guide in which optical fibers are bundled in high density from the entrance end to the exit end is used. Therefore, in order to increase the effective diameter of the secondary light source at the light guide exit end, a light guide in which a larger number of optical fibers are bundled is required. As a result, the flexibility of the light guide is reduced.

When a light guide having a multi-branched emission end side is used to form a plurality of illumination fields, it is necessary to configure the effective diameter of the secondary light source to be a required size at each emission end. . Therefore, all the optical fibers required at each exit end are converged into one at the entrance end, which reduces the flexibility of the light guide. If the flexibility of the light guide decreases, the load on the light guide increases due to the movement of the movable exit end side, and the optical fibers forming the light guide are more likely to be damaged such as broken. .

Further, as described above, in the conventional light guide in which the optical fibers are densely bundled from the entrance end to the exit end, it is necessary to bundle a large number of optical fibers in order to increase the effective diameter of the secondary light source at the exit end. was there. Therefore, when an optical fiber made of particularly expensive quartz glass is used, there is a disadvantage in that the cost is disadvantageous if the required number of optical fibers is large. The present invention has been made in view of the above problems, and an object of the present invention is to provide an illumination optical system in which the light guide has high flexibility and is not easily damaged by the movement of the exit end of the light guide.

[0012]

In order to solve the above problems, in the present invention, a light source means for supplying illumination light and a light source means for guiding the light from the light source means to the movable exit end. In an illumination optical system for irradiating a movable target with light from the movable exit end of the light guide means, the light guide means has a large number of bundled optical fibers, and the large number of optical fibers. Provides an illumination optical system in which the movable exit end side is bundled with a density substantially lower than that of the entrance end side.

According to another aspect of the present invention, the above-mentioned illumination optical system, an exposure illumination optical system for illuminating a mask on which a predetermined pattern is formed with exposure light, and a pattern image of the mask are provided. A projection optical system for forming on the photosensitive substrate, and a movable stage means for supporting the photosensitive substrate are provided, and the movable emitting end of the light guide of the illumination optical system is integrated with the movable stage means. Provided is a projection exposure apparatus, which is characterized in that

[0014]

In the present invention, a large number of optical fibers are bundled at a high density on the incident end side of the light guide means as in the prior art, and the optical fibers are bundled at a low density on the movable exit end side. Therefore, the flexibility of the light guide can be improved by reducing the number of optical fibers required for the light guide while ensuring the effective diameter of the exit end required for the illumination optical system. In this way, the load on the light guide due to the movement on the exit end side is reduced, and damage such as disconnection of the optical fiber can be avoided.

Since the optical fibers are packed at a low density within the effective diameter of the exit end of the light guide, the secondary fibers at the exit end are compared with the exit end of a normal light guide that is densely packed. The brightness of the light source is reduced. However, by increasing the brightness of the light source, the brightness of the secondary light source formed at the exit end of the light guide can be sufficiently ensured. Further, if the light from the secondary light source is converted into a parallel light flux through a condenser lens and Koehler illumination is performed, it is possible to obtain almost the same optical performance as when a conventional light guide is used as an illumination optical system.

[0016]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a diagram schematically showing the configuration of a projection exposure apparatus to which an illumination optical system according to an embodiment of the present invention is applied. When manufacturing a semiconductor device, a liquid crystal display device, etc., a reticle (or a photomask) is illuminated by an exposure illumination optical system, and a reticle pattern is exposed through a projection optical system to a wafer coated with a photoresist (or a glass plate or the like). A projection exposure apparatus for forming an image on the photosensitive substrate) is used. FIG.
Then, the z-axis is parallel to the optical axis of the projection optical system, the x-axis is parallel to the plane of FIG. 1 in the plane perpendicular to the optical axis, and the y-axis is parallel to the z-axis and the x-axis. Are set respectively.

The illustrated projection exposure apparatus comprises a light source 1 arranged at the first focal position of an elliptical mirror 2. As the light source 1, for example, a mercury lamp is used. When the light source 1 is a mercury lamp, for example, its bright line (g line, i line, etc.)
Is used as the exposure light. The light emitted from the light source 1 is condensed by the elliptical mirror 2 and forms a light source image at the second focal position. The light from the light source image is converted into a parallel light flux through the input lens 3 and then guided to the incident surface of the fly-eye lens 4 which is a multi-light source forming means.

The light incident on the fly-eye lens 4 is two-dimensionally divided by a plurality of lens elements forming the fly-eye lens 4, and a plurality of secondary light sources are formed near the exit surface thereof. The light from the plurality of secondary light sources is transmitted through the aperture stop 5
It enters into the main condenser lens 6 via. The light passing through the main condenser lens 6 is reflected by the mirror 7 and then illuminates the reticle 8 on which the pattern is formed in a superimposed manner. The reticle 8 is supported on the reticle stage 9. In this way, the light source 1, the elliptical mirror 2, the input lens 3, the fly-eye lens 4, the aperture stop 5,
The main condenser lens 6 and the mirror 7 form an exposure illumination optical system.

The light transmitted through the reticle 8 is projected by the projection optical system 1.
Through 0, it reaches the wafer 11 which is a photosensitive substrate positioned on its image plane. In this way, the pattern formed on the reticle 8 is transferred onto the wafer 11 by the projection optical system 10. The wafer 11 is supported on the wafer stage 13 via the wafer holder 12. The wafer stage 13 is an xy stage that positions the wafer 11 in an xy plane that is perpendicular to the optical axis of the projection optical system 10, a z stage that positions the wafer 11 in the z direction, and an inclination angle of the wafer 11 with respect to the xy plane. It is composed of a leveling stage and the like for correcting

The coordinates of the wafer stage 13 in the x direction and y
The directional coordinates are each measured by a laser interference system (not shown). Thus, the wafer stage 1
The pattern of the reticle 8 is successively transferred to each exposure region of the wafer 11 by performing exposure while appropriately driving two-dimensionally in the xy plane. A light-transmissive stage substrate 22 is attached near the wafer holder 12 on the wafer stage 13. Stage substrate 22
2, in the light-shielding film 23 formed on the upper surface of FIG.
c is formed.

On the other hand, the illustrated projection exposure apparatus is provided with a shutter 14 which can be inserted into and removed from the optical path between the light source 1 and the input lens 3. Shutter 14 is motor 1
The light from the light source image is selectively taken out of the optical path of the exposure illumination optical system at the position of the light source image formed at the second focal position of the elliptic mirror 2 by being driven by the optical disc 5. The light extracted to the outside of the optical path of the exposure illumination optical system forms a light source image at the incident end 17a of the light guide 17 via the lens system 16.

The light guide 17 is constructed by bundling a large number of optical fibers at random, and the exit end side is branched into two. At each exit end, half the number of optical fibers at the entrance end are branched. FIG. 3 is a diagram showing states of the incident end and the respective exit ends of the light guide 17 of FIG. As shown in FIG. 3, at the incident end 17a of the light guide 17, for example, 2n optical fibers 18 are densely packed. On the other hand, of the two exit ends of the light guide 17, the exit end 17b or 17c is filled with n optical fibers 18 at a low density. As a result, the effective diameter on the exit end side where there are only n optical fibers can be made larger than the effective diameter on the entrance end side consisting of 2n optical fibers.

As described above, in order to fill the optical fibers with a low density on the exit end side, for example, there is a method of bundling with a filler interposed between the optical fibers. In this case, an optical fiber having a diameter similar to that of the optical fiber can be used as a dummy for the filling material. Thus, the light incident on the incident end 17a of the light guide 17 is propagated to the two emitting ends 17b and 17c, respectively. The light flux from the exit end 17 b of the light guide 17 is reflected by the mirror 19 provided inside the wafer stage 13.
b through the condenser lens 20b and the reference mark 2
Koehler illumination of 1b. On the other hand, the light flux from the exit end 17c of the light guide 17 is a mirror 19c and a condenser lens 20c provided inside the wafer stage 13.
The reference mark 21c is Koehler-illuminated via.

The two emission ends 1 of the light guide 17 are
The 7b side and the 17c side are configured to move integrally with the wafer stage 13. Therefore, even if the wafer stage 13 moves two-dimensionally in the xy plane, the two reference marks 21b, which are movable targets, are generated by the light from the two emission ends 17b and 17c of the light guide 17.
And 24c surrounding the fields 21c and 21c, respectively.
c (see FIG. 2) can be formed.

As described above, the light source 1, the elliptical mirror 2, the shutter 14, the motor 15, the lens system 16, and the light guide 1
7, two mirrors 19b and 19c, and two condenser lenses 20b and 20c constitute an illumination optical system for alignment according to the embodiment of the present invention.
The illumination light from the illumination optical system for alignment is the light from the light source 1 of the exposure illumination optical system, and is the exposure light itself. Therefore, as shown in FIG.
With the center of 2 aligned with the optical axis of the projection optical system 10,
The lights from the reference marks 21b and 21c form two images of the reference marks on the reticle 8 via the projection optical system.

On the lower surface of the reticle 8 in the drawing, for example, two cross-shaped reticle marks 25b and 25c which are arranged symmetrically about the center along the x-axis direction are formed. Then, in a state where the reticle 8 is positioned at a predetermined position, the image of each reference mark is formed so as to surround the corresponding reticle mark. That is, the reticle marks 25b and 25c of the reticle 8 are the same as the reference mark 21b.
And 21c are illuminated respectively. Light from the images of the two reticle marks and the corresponding two fiducial marks is detected by alignment optics 26b and 26c, respectively.

FIG. 4 is a diagram schematically showing the configuration of the alignment optical system shown in FIG. The two alignment optical systems are optical systems that are symmetrically arranged with respect to the reticle along the x-axis direction and have the same configuration. Therefore, the configuration and operation of the alignment optical system will be described below, focusing on one alignment optical system.

The alignment optical system 26 on the right side in FIG.
In b, the light transmitted around the reticle mark 25b on the reticle 8 is reflected by the mirror 41 for deflecting the optical path, and then the half mirror 45 is passed through the first objective lens 42, the mirror 43 and the second objective lens 44. Incident on. The light reflected by the half mirror 45 forms a composite image of the reference mark 21b and the reticle mark 25b on the image pickup surface of a two-dimensional image pickup device 46 including a two-dimensional CCD. And
Based on the two-dimensional image data from the two-dimensional image sensor 46, for example, a relative displacement of the reticle mark 25b is detected by visual observation using the reference mark 21b as an index. Further, by performing image processing on the two-dimensional image data from the two-dimensional image pickup device 46, the above-mentioned relative positional deviation is detected as positional deviation of the reticle 8 at the x coordinate and the y coordinate on the wafer stage 13.

On the other hand, the light transmitted through the half mirror 45 is
An image of the reticle mark 25b that is transmitted and illuminated by illumination light that forms the image of the reference mark 21b as an illumination field (illumination field) is formed on the vibration slit 48 in the two-dimensional photoelectric microscope 47.
The y-axis photoelectric microscope of the two-dimensional photoelectric microscope 47 includes a y-direction vibration slit that vibrates on the image plane in a direction corresponding to the y direction of the reticle mark 25b on the reticle 8,
It is composed of a photoelectric detector such as a photomultiplier arranged immediately after the y-direction vibration slit. Then, by synchronously rectifying the output signal of the photoelectric detector with the vibration slit drive signal, the reticle mark 2 with respect to a predetermined reference position fixed with respect to the reticle stage 9.
It is possible to obtain a signal corresponding to the positional deviation amount in the y direction of 5b. That is, it is possible to detect the amount of positional deviation of the reticle mark 25b in the y direction with respect to the predetermined reference position.

The x-axis photoelectric microscope of the two-dimensional photoelectric microscope 47 includes an x-direction vibration slit that vibrates on the image plane in a direction corresponding to the x direction of the reticle mark 25b on the reticle 8, and this x direction. It is composed of a photoelectric detector such as a photomultiplier arranged immediately after the vibration slit. Then, by synchronously rectifying the output signal of the photoelectric detector with the vibration slit drive signal, a signal corresponding to the amount of positional deviation of the reticle mark 25b in the x direction with respect to a predetermined reference position fixed with respect to the reticle stage 9 is obtained. be able to. That is, it is possible to detect the amount of positional deviation of the reticle mark 25b with respect to the predetermined reference position in the x direction.

As described above, the alignment optical system 26c on the left side in FIG. 4 is also the alignment optical system 26 on the right side in FIG.
It is configured symmetrically along the b and x axis directions. Therefore, the two-dimensional image pickup device of the other alignment optical system 26c can detect the relative positional deviation amount of the reticle mark 25c using the other reference mark 21c as an index. Further, the two-dimensional photoelectric microscope of the alignment optical system 26c can detect the x-direction displacement amount and the y-direction displacement amount of the reticle mark 25c with respect to a predetermined reference position.

The alignment operation in the projection exposure apparatus having the above structure will be described below. In the projection exposure apparatus, it is necessary to accurately align (align) the reticle 8 and the wafer 11 during exposure.
Therefore, first, the alignment optical systems 26b and 26c
Based on the detection result of, the reticle 8 is aligned with the reticle stage 9, that is, the reticle alignment is performed. After completion of this reticle alignment, the wafer 1
The relative position of the reticle 8 is detected with the wafer stage 13 on which 1 is placed as a reference. Based on the detection result, the relative alignment between the reticle 8 and the wafer stage 13, and by extension, the alignment between the wafer 11 and the reticle 8 is performed.

To perform the alignment operation, the motor 1
5, the shutter 14 is driven so that the exposure light from the light source 1 is directed not to the exposure illumination optical system but to the illumination optical system of this embodiment for alignment. The light guided to the alignment illumination optical system illuminates the two reference marks 21b and 21c formed on the stage substrate 22. The lights from the two illuminated reference marks 21b and 21c form respective images on the two reticle marks 25b and 25c formed on the reticle 8 via the projection optical system 10. That is, the reticle marks 25b and 25c of the reticle 8 are illuminated by the images of the reference marks 21b and 21c, respectively.

The light transmitted around the reticle marks 25b and 25c on the reticle 8 is detected by the alignment optical systems 26b and 26c, respectively. Then, based on the output signal from the two-dimensional photoelectric microscope of each alignment optical system, the reticle mark 25 for a predetermined reference position is obtained.
The x-direction displacement amount and the y-direction displacement amount of b and 25c are detected. Thus, based on this detection result,
In order that the x-direction positional deviation amount of the reticle 8 with respect to the reticle stage 9, the y-direction positional deviation amount, and the rotation angle (around the z-axis) in the xy plane fall within the allowable ranges,
Reticle alignment can be performed by appropriately moving the reticle 8.

Further, based on the output from the two-dimensional image pickup device of each alignment optical system, the reference marks 21b and 2b.
The relative displacement between 1c and the reticle marks 25b and 25c is detected. Thus, based on this detection result, the x-direction positional deviation amount between the reticle 8 and the wafer stage 13, the y-direction positional deviation amount, and the rotation angle (around the z-axis) in the xy plane are each within the allowable range.
For example, relative alignment can be performed by moving the wafer stage 13.

As described above, in the illumination optical system of the present embodiment, the optical fibers 18 are normally filled with high density on the incident end 17a side of the light guide 17, and the exit end side 17b is filled.
And 17c, the optical fiber 18 is filled with low density. Thus, the effective diameter of the exit end required for the illumination optical system is secured, and the number of optical fibers required for the light guide is reduced to improve the flexibility of the light guide.

As described above, as a simple method for filling the optical fiber at the exit end side of the light guide with a low density, a dummy optical fiber (having the same diameter as the used optical fiber) is provided only at the exit end side. In addition, there is a method of bundling. According to such a manufacturing method, the light guide suitable for the illumination optical system of the present invention can be manufactured and handled almost in the same manner as a normal light guide.

The wafer stage of the projection exposure apparatus is usually two-dimensionally driven by the step & repeat method during exposure. For this reason, the number of times the wafer stage is driven is very large, and the driving speed is also high. In addition, the wafer stage must repeat stationary and moving with extremely high positioning accuracy. Therefore, by improving the flexibility of the light guide having the emitting end that moves integrally with the wafer stage, the load on the light guide due to the driving of the wafer stage is reduced, and the optical fiber forming the light guide may be disconnected. The possibility of damage can be reduced.

Further, by using a light guide having a low optical fiber filling rate at the exit end side, the brightness of the secondary light source at the exit end is higher than that of a normal light guide in which both ends are densely filled with optical fibers. descend. However, in the case where a light source (mercury lamp) shared with the exposure illumination optical system is used as in the present embodiment, or when the brightness of the light source for alignment is sufficiently high and there is a margin, the light is emitted at the exit end. The decrease in the brightness of the is not a problem. That is, by using a light source having sufficiently high brightness, it is possible to obtain a secondary light source having sufficient brightness at the light guide exit end. Further, according to the configuration of the present embodiment, it is easy to bundle the optical fibers randomly so that the change in the light amount distribution of the light source image at the light guide entrance end does not affect the light amount distribution at the exit end.

In general, an optical fiber made of quartz glass has a higher unit price of a single wire than an optical fiber made of multi-component glass or the like. However, according to this embodiment, the number of optical fibers used for the light guide can be reduced, which is advantageous in cost particularly when using a light guide made of silica glass optical fibers.

In the above embodiment, the mercury lamp is used as the light source, but the present invention can be applied to the case where an excimer laser or the like is used by appropriate modification. Further, in the above-described embodiments, the example in which the illumination optical system of the present invention is applied to the projection exposure apparatus has been shown, but the present invention can be applied to other general illumination optical systems for irradiating a movable target. . Further, in the above-described embodiment, an example in which the illumination optical system of the present invention and the exposure illumination optical system of the projection exposure apparatus share a light source has been shown, but the illumination optical system of the present invention has a dedicated light source. You can also do it.
In this case, it is preferable that the illumination light from the dedicated light source has sufficient brightness and the same wavelength as the exposure light. Further, in the above-described embodiment, an example in which the light guide having the two emission ends is used is shown. However, a light guide having only one emission end and a light guide having three or more emission ends are used. It can also be used.

[0042]

As described above, in the illumination optical system of the present invention, it is necessary to increase the effective diameter of the secondary light source at the light guide exit end, or a multi-branch light guide having two or more exit ends is used. Even when used, the number of optical fibers used in the light guide can be reduced, and the flexibility of the light guide is improved. Therefore, it is possible to reduce the load on the light guide due to the drive of the light guide emission end, and it is possible to suppress damage such as disconnection of the optical fiber forming the light guide. Also,
In particular, when the light guide is constructed by using an optical fiber made of quartz glass, it is advantageous in cost because the number of optical fibers to be used is reduced.

Further, in the projection exposure apparatus of the present invention provided with the illumination optical system of the present invention, the light guide exit end of the illumination optical system moves integrally with the movable stage means for the photosensitive substrate,
For example, the reference mark formed on the movable stage means can be illuminated. As described above, the light guide of the illumination optical system according to the present invention has high flexibility, and damage to the illumination optical system due to the influence of the movable stage means that repeats stationary and moving at a very high speed can be avoided. Therefore,
For example, in the projection exposure apparatus of the present invention in which the illumination optical system of the present invention is incorporated as an alignment illumination optical system, it is possible to perform highly accurate and highly reliable alignment operation.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a configuration of a projection exposure apparatus to which an illumination optical system according to an embodiment of the present invention is applied.

FIG. 2 is a diagram showing two fiducial marks formed on the stage substrate of FIG.

FIG. 3 is a diagram showing states of an entrance end and each exit end of the light guide of FIG.

FIG. 4 is a diagram schematically showing a configuration of the alignment optical system of FIG.

FIG. 5 is a diagram schematically showing a configuration of a conventional illumination optical system for illuminating a movable target.

[Explanation of symbols]

 1 Light Source 2 Elliptical Mirror 3 Input Lens 4 Fly's Eye Lens 5 Aperture Stop 6 Main Condenser Lens 7 Mirror 8 Reticle 9 Reticle Stage 10 Projection Lens 11 Wafer 12 Wafer Holder 13 Wafer Stage 14 Shutter 15 Motor 16 Lens System 17 Light Guide 18 Optical Fiber 19 Mirror 20 Condenser lens 21 Reference mark 22 Stage substrate 25 Reticle mark 26 Alignment optical system

Claims (4)

[Claims] 1. A light source means for supplying illumination light, and a light guide means for guiding light from the light source means from an incident end to a movable emission end. From the movable emission end of the light guide means. In the illumination optical system for irradiating the movable target object with the light, the light guide means has a large number of bundled optical fibers, and the plurality of optical fibers are substantially closer to the movable emission end side than to the incident end side. An illumination optical system characterized by being bundled in a low density. 2. The illumination optical system according to claim 1, wherein the plurality of optical fibers of the light guide means are randomly bundled. 3. The illumination optical system according to claim 1, an exposure illumination optical system for illuminating a mask on which a predetermined pattern is formed with exposure light, and a pattern image of the mask on a photosensitive substrate. A projection optical system for forming the photosensitive substrate, and a movable stage means for supporting the photosensitive substrate, wherein the movable exit end of the light guide of the illumination optical system moves integrally with the movable stage means. And a projection exposure apparatus. 4. The projection exposure apparatus according to claim 3, wherein the exposure illumination optical system illuminates the mask based on light from the light source of the illumination optical system.