JPH09179033A - Observation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the observation device equipped with a transmission lighting system which has simple constitution and is easily assembled and adjusted. SOLUTION: Illumination light ILC emitted by the light emission part in a ring-zone shape at the projection opening 2C of an optical fiber bundle IC provides critical lighting for a luminous flux passing area 23 in a ring-zone shape at the periphery of a body 9 to be inspected on the inspected surface HP of a light-transmissive substrate 8 through a relay lens 21, a half-mirror 12, an aperture stop 11, and a 1st objective 10. The illumination light ILC transmitted through the substrate 8 from the luminous flux passing area 23 while converged by a reflection type condenser lens 22 is reflected by a reflection surface 22a, and then converged again by the reflection type condenser lens 22 and transmitted through the substrate 8 to uniformly light up an inspected area inside the luminous flux passing area 23 on the inspected surface HP.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an observing apparatus for observing an object formed on a predetermined substrate, and in particular, for manufacturing a microscope, a semiconductor element, etc. for observing an object with transmitted illumination. It is used for an alignment microscope for detecting the position of a mask with a projection exposure apparatus for, or for an alignment microscope for aligning the mask and the glass substrate with a proximity type exposure apparatus for manufacturing liquid crystal display elements. It is suitable.

[0002]

2. Description of the Related Art Conventionally, in order to observe or detect an object formed on a predetermined substrate, the object is illuminated by epi-illumination or transmitted illumination to form an image of the object. An observation device such as a microscope is used. In this case, epi-illumination and transmitted illumination are used differently depending on the type of the object to be inspected or the substrate or the application of the observation device. For example, in a projection exposure apparatus (stepper or the like) used when manufacturing a semiconductor device or the like, an alignment microscope for detecting the position of an alignment mark formed on a reticle as a mask, or a projection for manufacturing a liquid crystal display device. An alignment microscope for detecting the position of an alignment mark formed on a glass substrate as a photosensitive substrate by an exposure device is equipped with a transmission illumination system and / or an epi-illumination system. On the other hand, an alignment microscope for detecting an alignment mark formed on a substrate that is opaque to visible light, such as a semiconductor wafer, is equipped only with an epi-illumination system.

Further, for example, in a proximity type exposure apparatus for manufacturing a liquid crystal display element, when the mask and the glass substrate are aligned, for example, when the layer of the opaque film on the glass substrate is aligned. When the epi-illumination system is used and the positions of the semitransparent film or the transparent film layer (ITO layer, color filter layer, black matrix layer, etc.) on the glass substrate are aligned, it is necessary to perform switching such as using the transillumination system. is there. Therefore, such a proximity type exposure apparatus is provided with an alignment microscope having both an epi-illumination system and a transmitted illumination system.

FIG. 5 shows a microscope equipped with both a conventional transillumination system and an epi-illumination system. In FIG. 5, the illumination light from a light source (not shown) is the optical fiber bundles 1A and 1B.
Are branched into a transmission illumination system and an epi-illumination system, respectively. First, in the transmissive illumination system, the illumination light ILA emitted from the emission port 2A of the optical fiber bundle 1A includes the first relay lens 3A, the field stop 4, the second relay lens 3B, the optical path bending mirror 5, and the aperture stop 6. , And the condenser lens 7 to illuminate the test object 9 on the light-transmissive substrate 8 through transmission illumination. The illumination area including the inspection object 9 is limited by the field stop 4, and the numerical aperture (NA) of the transillumination system is the aperture stop 6.
Alternatively, it is limited by the size of the light emitting portion (secondary light source) of the emission port 2A.

Further, the exit surface of the exit port 2A and the surface on which the test object 9 is formed (test surface) have an optical Fourier transform relationship, that is, a light emitting portion (secondary light source) on the exit surface. The image of () is formed on the front focal plane of the condenser lens 7 to form so-called Koehler illumination. Then, the illumination light from the inspection object 9 passes through the first objective lens 10, the aperture stop 11, the half mirror 12, and the second objective lens 13 to generate a two-dimensional C
An image of the test object 9 is formed on the image pickup surface of the image pickup device 14 made of a CD.

On the other hand, in the epi-illumination system, the illumination light ILB emitted from the emission port 2B of the optical fiber bundle 1B is relay lens 15, field stop 16, and condenser lens 1.
Reach the half mirror 12 through 7, and then the half mirror 12
The illumination light ILB reflected by (1) passes through the aperture stop 11 and the first objective lens 10 and epi-illuminates the test object 9 on the substrate 8. The illumination area at this time is limited by the field stop 16, and the numerical aperture of the epi-illumination system is the aperture stop 11 or the exit port 2.
It is limited by the size of the B light emitting portion (secondary light source). In this epi-illumination system as well, the exit surface of the exit port 2B and the surface to be inspected are in an optical Fourier transform relationship, which is Koehler illumination. Then, at the time of observation, when the inspection object 9 is formed on the light-transmissive substrate 8, for example, a transmissive illumination system is used, and when the inspection object 9 is formed on an opaque substrate, The two illumination systems were switched and used, such as using the epi-illumination system.

[0007]

In the prior art as described above, for example, when only an object to be inspected formed on a transparent substrate is to be observed, a microscope having only a transillumination system can be used. However, since the transillumination system is an optical system that is arranged so as to face the imaging system through the transparent substrate and includes a light source such as an optical fiber bundle and a condenser lens, the overall size of the microscope increases. There was an inconvenience. Further, it takes time to assemble and adjust the optical axis of the imaging system and the transillumination system, which are arranged to face each other with the object to be examined in between.

Further, for example, in a proximity type exposure apparatus, an alignment microscope having both an epi-illumination system and a transmissive illumination system is used. In this case, the epi-illumination system is added to the image forming system side. Therefore, there is a problem that the microscope is further enlarged and a large space is required when the microscope is incorporated in the exposure apparatus. Further, in the alignment microscope, a transmissive illumination system including an optical fiber bundle is arranged inside the substrate stage that supports the glass substrate. However, if the optical fiber bundle is routed inside the substrate stage in this way, a stage mechanism is used. However, there is a disadvantage that the positioning accuracy of the substrate stage is adversely affected as well as becoming complicated.

In view of the above problems, it is a first object of the present invention to provide an observing device which has a simple structure, is easy to assemble and adjust, and which is capable of transmitting and illuminating a test object to form an image thereof.
A second object of the present invention is to provide an observing device which can illuminate an object to be examined and form an image thereof by either epi-illumination or transmitted illumination with a simple structure.

[0010]

As shown in FIGS. 1 and 2, for example, an observation apparatus according to the present invention is an illumination optical system for illuminating an object (9) supported on a light-transmissive substrate (8). System and an objective lens (1 that collects the illumination light from the test object
0) to form an image of the object to be inspected (1)
0, 13), and the illumination optical system is such that the illumination optical system uses the illumination light from the side of the objective lens (10) to the substrate (8).
First for illuminating the light flux passing area (23) outside the upper test area
An illumination optical system (1C, 2C, 21, 12, 10) and a light flux including a reflection member (22a; 26) arranged so as to face the objective lens (10) with respect to the substrate (8), and which is outside the region to be inspected. A second illumination optical system (22; 24) that reflects the illumination light that has passed through the passage area (23) and focuses it on the test area;
It is provided with.

According to the present invention, the first illumination optical system illuminates the light transmissive substrate (8) from the objective lens (10) side like the conventional epi-illumination system. A light flux passing area (2) outside a predetermined test area including the test object (9)
Illuminate 3). Then, the illumination light that has passed through the light flux passage area (23) is reflected by the second illumination optical system (22; 24) having a simple structure including the reflection member (22a; 26) and is condensed on the inspection area. . The first illumination optical system can be adjusted in the same manner as the conventional epi-illumination system, and the second illumination optical system (22; 2
4) is adjusted so that the light flux from the light flux passage area (23) is guided to the test area, the assembly and adjustment are easy.

In this case, although the illumination light from the first illumination optical system may pass through the objective lens (10) (bright field illumination), it passes through the outside of the objective lens (10) and the substrate (8).
You may turn to (dark field illumination). In addition, a light flux passing area (2) outside the test area on the light transmissive substrate (8).
The shape of 3) is preferably annular. The second illumination optical system reflects and collects the illumination light that has passed through the ring-shaped light flux passage region (23), so that the subject region is isotropically and uniformly transmitted and illuminated.

The area to be detected on the substrate (8) is the second area.
It is desirable that the illumination optical system (22; 24) is arranged on the same plane as the front focal plane. At this time, a light source image is formed in the light flux passing region (23) by the first illumination optical system and is set as critical illumination, so that the subject region is illuminated by so-called Koehler illumination. Further, as shown in FIG. 3, for example, a light source (2 Da) having a predetermined shape is provided,
A third illumination optical system (1D, 2D, 27, 21, 12, 10) is provided for epi-illuminating the test area on the substrate (8) from the objective lens (10) side with illumination light from this light source. It is desirable to share at least a part (21, 10) of the optical member of the first illumination optical system and the optical member of the third illumination optical system. According to the present invention, the first illumination optical system and the second illumination optical system constitute a transmissive illumination system, and the third illumination optical system serves as an epi-illumination system, which is one of the epi-illumination system and the transmissive illumination system. The optical members of the section are commonly used.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of an observation apparatus according to the present invention will be described below with reference to FIG. In this example, the present invention is applied to a microscope for observing an object to be inspected with transmitted illumination, and in FIG. 1, parts corresponding to those in FIG. 5 are denoted by the same reference numerals and detailed description thereof will be omitted.

FIG. 1A shows a microscope of this example, and in FIG. 1A, illumination light from a light source (not shown) is guided to a predetermined position through an optical fiber bundle 1C and an emission port 2C. . The optical fiber bundle 1C is a bundle of a large number of optical fibers that are randomly bundled, and the light emitting portion on the exit surface HC of the exit port 2C can be regarded as a secondary light source. As shown in FIG. 1B, the light emitting portion 2Ca of the emission port 2C has an annular shape. Depending on the object to be inspected, the light emitting portion 2Ca may have, for example, a rectangular frame shape.

The illumination light ILC emitted from the ring-shaped light emitting portion reaches the half mirror 12 via the relay lens 21 along the optical axis AX2, and the illumination light ILC reflected by the half mirror 12 has the optical axis AX1. Along the aperture stop 11,
Further, via the first objective lens 10, the annular light flux passage area 23 around the object 9 on the surface of the light transmissive substrate 8 is epi-illuminated. In this case, the exit surface HC of the illumination light ILC and the test surface (here, the surface) HP of the substrate 8 are conjugate, and the light flux passing region 23 around the test object 9 is formed on the exit surface HC. It is a conjugate image of the ring-shaped light emitting portion (secondary light source) 2Ca. That is, the light flux passage area 23 is illuminated by the illumination light ILC.
Critically illuminated by.

In this example, the reflective condenser lens 22 is arranged so as to face the first objective lens 10 with the substrate 8 interposed therebetween. This reflective condenser lens 22 is
It is composed of a plano-convex lens having a positive refractive power with the convex surface facing the substrate 8 side, and the plane portion on the opposite side of the substrate 8 is the reflecting surface 22a. The position of the reflective condenser lens 22 is set so that the front focal plane and the rear focal plane of the reflective condenser lens 22 coincide with each other and the front focal plane of the reflective condenser lens 22 is on the test surface HP.

The illumination light ILC that has passed through the substrate 8 from the annular light flux passage area 23 on the surface HP to be inspected is condensed by the reflective condenser lens 22 and is reflected on the reflective surface 22.
After being reflected by a, it is further condensed by the reflective condenser lens 22 and transmitted through the substrate 8 to make the circular test area (observation field of view) inside the light flux passing area 23 on the test surface HP uniform. Illuminate with illuminance distribution. In this case, since the surface HP to be inspected is both the front focal plane and the rear focal plane of the reflective condenser lens 22, its observation field of view has an optical Fourier transform relationship with the annular light flux passage area 23, which is so-called. Ring-shaped Koehler lighting is used.

Illumination light ILC from the object 9 in the observation field of view is irradiated by the first objective lens 10 along the optical axis AX1.
An image of the test object 9 is formed on the image pickup surface of the image pickup device 14 via the aperture stop 11, the half mirror 12, and the second objective lens 13. Then, the image pickup signal from the image pickup device 14 is image-processed by a signal processing device (not shown), and
Is observed or the position is detected.

Thus, according to this example, the optical fiber bundle 1
C, exit 2C, relay lens 21, half mirror 1
2 and the first illumination optical system including the first objective lens 10, the luminous flux passage area 23 around the original observation field (inspection area).
The illumination light that has passed through the light flux passage area 23 is reflected and condensed by the second illumination optical system including the reflection type condenser lens 22, and the observation visual field is transmitted and illuminated. Therefore, the structure of the microscope is simplified and the reflective condenser lens 2 is used as compared with a conventional microscope having a transmitted illumination system.
The adjustment 2 is only required to direct the illumination light that has passed through the light flux passage area 23 to a desired observation field of view, so that the assembly and adjustment of the optical system is easy. Further, since the configuration of the side of the substrate 8 facing the first objective lens 10 is simple with only the reflective condenser lens 22 and does not include an optical fiber bundle or the like, it is particularly suitable for various devices such as an exposure device and an inspection device. It is extremely easy to incorporate.

In the example of FIG. 1, in order to simplify the structure most, the conjugate surface (light flux passage area 23) of the exit surface HC of the illumination light ILC, the test surface HP, and the reflective condenser lens 22.
The front focal plane is located on the same plane, and the surface HP to be tested and the rear focal plane of the reflective condenser lens 22 are located on the same plane. However,
In the case where it is sufficient to illuminate the test object 9 only with the transmissive illumination, the illumination light I directed from the first objective lens 10 side to the substrate 8 is used.
It may be set so that the LC does not illuminate a desired observation visual field (test area) including the test object 9. Further, when it is desired to simply illuminate the observation visual field with a uniform illuminance distribution, the illumination light IL
It suffices that the image (light source image) of the exit surface HC of C be substantially matched with the front focal plane of the reflection type condenser lens 22 to be almost Koehler illumination.

Further, in the example of FIG. 1, the exit surface H of the exit port 2C.
Although the light emitting portion of C (the cross-sectional shape of the optical fiber bundle) has a ring shape, the light emitting portion may have a circular shape and the secondary light source may be limited to a ring shape or a rectangular frame shape by a diaphragm or the like. In the former case, the numerical aperture (NA) of the illumination system is limited by the sectional shape of the optical fiber bundle on the exit surface HC, and in the latter case, the numerical aperture of the illumination system is limited by the diaphragm or the like. Further, although bright field illumination is used in the example of FIG. 1, the illumination light from the reflection type condenser lens 22 is increased by increasing the outer diameter of the exit 2C or shortening the focal length of the reflection type condenser lens 22. The dark field illumination may be substantially performed by preventing the 0th-order light of the ILC from entering the first objective lens 10.

Next, a modified example of the above-described first embodiment will be described with reference to FIG. This modification is the second of FIG.
The reflection type condenser lens 22 as the illumination optical system is divided into two members. In FIG. 2, the parts corresponding to those in FIG. 1 are designated by the same reference numerals and the detailed description thereof will be omitted. FIG. 2 shows the configuration of this modification. In FIG.
A reflection / focusing optical system 24 is arranged so as to face the first objective lens 10 with the substrate 8 interposed therebetween.
Is composed of a condenser lens 25 having a positive refracting power in order from the side closer to the substrate 8, and a reflection type diffusion plate 26 having a rough reflection surface that randomly scatters the incident light flux. The rough reflecting surface of the reflective diffuser plate 26 is located on the front focal plane of the condenser lens 25, and the test surface HP on the substrate 8 on which the test object 9 is formed becomes the rear focal surface of the condenser lens 25. As described above, the condenser lens 25 and the reflection type diffusion plate 26 are positioned. Other configurations are the same as those in the example of FIG.

In FIG. 2, the illumination light ILC emitted from the emission port 2C of the optical fiber bundle 1C is the relay lens 21.
The ring-shaped light flux passage area 23 around the object 9 to be inspected on the surface HP to be inspected is critically illuminated via the above. Then, the illumination light ILC transmitted from the light flux passage area 23 through the substrate 8 is condensed by the condenser lens 25 on the reflection surface of the reflection type diffusion plate 26, and the irradiation area of the reflection surface of the reflection type diffusion plate 26 is formed by an optical fiber. Similar to a randomly bundled optical fiber bundle, a pseudo light source image is obtained. The illumination light ILC diffused in the irradiation area of the reflection surface is condensed by the condenser lens 25, passes through the substrate 8 again, and illuminates the inspection area (observation field of view) including the inspection object 9 through the transmission. In this case, the surface HP to be inspected has an optical Fourier transform relationship with the surface of the reflective diffuser plate 26 (a plane having a pseudo light source image) by the condenser lens 25, so that pseudo Koehler illumination is performed, The uniformity of the illuminance distribution in the observation visual field is good.

Also in this modification, the outer diameter of the light emitting portion (secondary light source) of the exit 2C of the optical fiber bundle 1C (or the size of the aperture of the diaphragm when using the diaphragm), or The numerical aperture of the illumination system can be limited by the size of the reflective surface of the reflective diffuser plate 26. Further, the reflection type diffusion plate 26
It is also possible to dispose a diaphragm or the like immediately before the reflecting surface of No. 2 and limit the numerical aperture of the illumination system by this diaphragm or the like.

Next, a second embodiment of the present invention will be described with reference to FIG. In this example, an epi-illumination system is further added to the first embodiment. In FIG. 3, parts corresponding to those in FIG. 1 are denoted by the same reference numerals and detailed description thereof will be omitted. FIG. 3A shows the microscope of this example,
In FIG. 3A, the illumination light from a light source (not shown) is emitted through the optical fibers 1C and 1D, respectively, and the emission port 2 is emitted.
Guided by C and 2D. As shown in FIG.
The shape of the light emitting part (secondary light source) 2Ca of the one exit 2C is a ring shape, and as shown in FIG. 3C, the shape of the light emitting part (secondary light source) 2Da of the other exit 2D is circular. Is.
Then, the illumination light ILC emitted from one emission port 2C
Enters the field combining prism 28. The field-of-view synthesizing prism 28 is formed by bonding two right-angle prisms at their hypotenuses in order to reduce the light amount loss of the illumination light from the two exits 2C and 2D, and the ring-shaped outer edge 28a of the joint surface is a reflecting surface. The circular central portion 28b is used as the transmission surface. However, instead of the field-of-view synthesis prism 28, a half mirror or a half prism may be used.

The illumination light ILC is used for the field combining prism 2.
After being reflected by the outer edge portion 28a of the joint surface of No. 8, the optical axis AX2
The illumination light ILC, which reaches the half mirror 12 via the relay lens 21 along the path, is transmitted through the aperture stop 11 and the first objective lens 10 to the substrate 8
A light source image is formed in the annular light flux passage area 23 around the object 9 on the surface HP to be inspected. Then, the light flux passage area 23
The illumination light ILC that has passed through the substrate 8 from is reflected and condensed by the reflective condenser lens 22, then passes through the substrate 8 again, and is a circular test object inside the light flux passage area 23 on the test surface HP. The area (viewing field) is illuminated by Koehler illumination.

Illumination light I emitted from the other emission port 2D
The LD passes through the relay lens 27 and then the visual field combining prism 28.
After passing through the circular central portion 28b of the joining surface of the optical axis AX,
2 reaches the half mirror 12 via the relay lens 21 and the illumination light ILD reflected by the half mirror 12 is
The substrate 8 via the aperture stop 11 and the first objective lens 10.
The circular test area (observation field of view) including the test object 9 on the test surface HP is illuminated by epi-illumination with a uniform illuminance distribution. That is, the exit surface HD of the exit port 2D and the surface HP to be inspected have an optical Fourier transform relationship, and the epi-illumination by the normal Koehler illumination is performed by the illumination light ILD. The other configuration is shown in FIG.
The image of the test object 9 is formed on the image pickup surface of the image pickup device 14 in the same manner as in the above example.

Thus, in this example, the optical fiber bundle 1C,
A transmissive illumination system is configured by the first illumination optical system including the exit 2C, the relay lens 21, the half mirror 12, and the first objective lens 10, and the second illumination optical system including the reflective condenser lens 22. 1D, ejection port 2
A third illumination optical system including D, the relay lens 27, the relay lens 21, the half mirror 12, and the first objective lens 10 constitutes an epi-illumination system. Then, the relay lens 21, the half mirror 12, and the first objective lens 10 are shared by the transmissive illumination system and the epi-illumination system, and one visual field synthesizing prism 28 is used for synthesizing two illumination lights.
Is used, compared to the conventional case where the transillumination system and the epi-illumination system are configured completely independently,
The structure of the entire optical system is simplified. Moreover, since it is not necessary to provide a light source such as an optical fiber bundle on the side facing the first objective lens 10 with the substrate 8 sandwiched between them, it is particularly easy to incorporate it in an exposure device or the like.

Now, switching between transmitted illumination and epi-illumination in the microscope of this example will be described. For example, instead of the transparent substrate 8, when a substrate whose surface to be inspected is covered with a light-reflective film such as a metal film is used, both the transillumination illumination system and the epi-illumination illumination system can be used simultaneously. The substrate may be illuminated. Even in this case, the light flux passing region 23 illuminated by the transmissive illumination system is out of the observation field of view, so that the image sensor 14 observes the image of the test object illuminated only by the epi-illumination system including the exit 2D. Will be.

On the other hand, as shown in FIG. 3A, when the light-transmissive substrate 8 is used, if the substrate 8 is simultaneously illuminated by both the transillumination illumination system and the epi-illumination illumination system, the image pickup device 1
In 4, the image of the test object 9 illuminated by the transmission illumination and the image of the test object 9 illuminated by the epi-illumination are observed in an overlapping manner. Moreover, among the illumination light ILD emitted from the epi-illumination system, the illumination light that has passed through the substrate 9 and passed through the substrate 8 is reflected by the reflective condenser lens 22 to illuminate the subject 9 again. It will also be done. The illumination light ILD reflected by the reflective condenser lens 22 in this way
Since the exit surface HD of the exit port 2D and the test surface HP are conjugate with each other, the exit port 2 is provided in the observation visual field including the test object 9.
Irregularity of illuminance is caused by the fibers of the optical fiber bundle at D. Therefore, in order to accurately observe the object 9 to be inspected on the light-transmissive substrate 8, as a first method, the illumination light IL with a shutter or the like is provided between the light source and the field synthesis prism 28.
It suffices to shield D from the light, or diminish the illumination light ILD to illuminate the object 9 with only the illumination light ILC from the transmissive illumination system.

As a second method, the illumination light ILC of the transmissive illumination system is blocked or dimmed, and an openable / closable shutter provided between the substrate 8 and the reflection type condenser lens 22 is closed to substantially reduce the light. It is also possible to illuminate the test object 9 only with the illumination light ILD from the epi-illumination system and from the first objective lens 10 side. By thus providing the means for switching between the transillumination system and the epi-illumination system (shutter or the like), the illuminance adjusting means, etc., the trans-illumination system and epi-illumination system in which a part of the optical member as in this example is shared. Can be used according to the intended use.

Next, a third embodiment of the present invention will be described with reference to FIG. In this example, the microscope in which the epi-illumination system according to the second embodiment shown in FIG. 3 is used as an annular illumination is applied to an alignment microscope of a proximity type exposure apparatus for manufacturing a liquid crystal display element. 4, parts corresponding to those in FIG. 3 are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 4A shows an alignment microscope of this example. In FIG. 4A, a mask 29 made of a glass substrate on which a transfer pattern is formed, and a glass substrate 30 coated with a photoresist are shown. Are held by a stage system (not shown) with a predetermined gap maintained. At the time of exposure, the pattern of the lower surface (pattern forming surface) of the mask 29 is transferred to the upper surface of the glass substrate 30 under exposure light, but before that, the alignment marks 31 and the like on the lower surface of the mask 29 and the upper surface of the glass substrate 30 are transferred. It is necessary to perform alignment with the alignment mark 32 and so on. For the alignment, the alignment microscope of this example is arranged so as to sandwich the mask 29 and the substrate 30.

In FIG. 4 (a), at the time of transmitted illumination, a ring-shaped light emitting portion 2 of an exit 2C of one optical fiber bundle 1C.
Illumination light ILC emitted from Ca (see FIG. 4B)
Is reflected by the half prism 33, then passes through the relay lens 21 and the half mirror 12, and then, between the mask 29 and the glass substrate 30 via the aperture stop 11 and the first objective lens 10 along the optical axis AX1. Then, a light source image is formed in the annular light flux passage region around the optical axis AX1. In this case, the alignment mark 31 on the mask 29 and the alignment mark 32 on the glass substrate 30 are roughly positioned in advance near the optical axis AX1. Then, the illumination light ILC that has passed through the mask 29 and the glass substrate 30 is reflected and condensed by the reflective condenser lens 22, and then passes through the glass substrate 30 again, and the test region including the alignment marks 32 and 31 (observation field of view). ) Is transmitted illumination with the Koehler illumination system of the zone.

During epi-illumination, the light emitting portion (secondary light source) 2E in the annular shape of the exit 2E of the other optical fiber bundle 1E.
The illumination light ILE emitted from a (see FIG. 4C) is
After passing through the half prism 33 through the relay lens 27 and the field stop 34, the relay lens 21 and the half mirror 1
2, the aperture stop 11, and the alignment mark 31 of the mask 29 and the glass substrate 3 through the first objective lens 10.
The subject area including the alignment mark 32 of 0 is illuminated by epi-illumination. At this time, the exit surface of the exit port 2E is the relay lens 2
Since 7 and 21 are conjugate with the arrangement surface of the aperture stop 11 and the arrangement surface of the aperture stop 11 coincides with the front focal plane of the first objective lens 10, the epi-illumination thereof is the annular zone Koehler. It is lighting. As a result, the light flux that has passed through the glass substrate 30 in the illumination light ILE that is epi-illuminated is reflected by the reflective condenser lens 22 and then passes outside the region to be inspected (observation field of view). Irregularity of illuminance does not occur in the observation visual field.

The other structure is similar to that of the example of FIG.
Alignment mark 3 by objective lenses 10 and 13
Images 1, 32 are formed on the image sensor 14. And
The position shift amount between the alignment marks 31 and 32 is detected by image processing the image pickup signal from the image pickup device 14, and the position of the mask 29 or the glass substrate 30 is adjusted so that the position shift amount falls within a predetermined allowable range. To be done.

As described above, according to the present embodiment, by performing the annular Koehler illumination for both the transmitted illumination and the epi-illumination,
Even if either transmitted illumination or epi-illumination is used, the alignment marks 29,
30 can be illuminated. Therefore, for example, when the transmission illumination and the epi-illumination are switched by the shutters provided immediately before the exits 2C and 2E, a good observation image can be obtained on the image pickup device 14, respectively. Further, a mechanism for adjusting the light amount of the illumination light supplied to the optical fiber bundles 1C and 1E is provided, and the illumination light ILC and I are transmitted through the light amount adjustment mechanism in the state where the transmission illumination and the epi-illumination are simultaneously performed.
It is also possible to obtain the best observed image on the image sensor 14 by adjusting the illuminance of LE.

The observation apparatus of the present invention is used, for example, in the case of manufacturing a semiconductor element, a liquid crystal display element, etc., and is a projection device for transferring a pattern image of a reticle onto a wafer, a glass plate or the like via a projection optical system. It can also be used as an alignment system for an exposure device (stepper, etc.). That is, in such a projection exposure apparatus, a reference member having a predetermined reference mark made of a light-transmissive substrate is fixed on a wafer stage on which a wafer or the like is placed, and an optical fiber is attached to the bottom of the reference member. Some have a transillumination system that includes a bundle or the like. Then, by illuminating the reference mark with the transmission illumination system and receiving an image of the reference mark by the projection optical system via the alignment mark on the reticle,
The amount of misalignment of the alignment mark with respect to the reference mark is detected. In this case, the present invention is applied to the bottom of the reference member, for example, the reflective condenser lens 22 of FIG.
The arrangement on the wafer stage side can be simplified.

As described above, the present invention is not limited to the above-described embodiments, and various configurations can be adopted without departing from the gist of the present invention.

[0041]

According to the observing apparatus of the present invention, the first illumination optical system illuminates the light flux passage area on the substrate from the objective lens side, and the second illumination optical system illuminates the light flux passage area. Since the illumination light that has passed through is reflected and focused on the region to be inspected, it is possible to perform transillumination with a simpler configuration than in the case of using a conventional transillumination system. and,
Since the second illumination optical system only needs to direct the illumination light that has passed through the light flux passage area to the area to be inspected, there is an advantage that assembly and adjustment are easy. In addition, the observation apparatus of the present invention has the second surface facing the objective lens with respect to the substrate.
Since the configuration of the illumination optical system side is simple and it is not necessary to provide a light source such as an optical fiber in the second illumination optical system,
It can be easily incorporated into an exposure apparatus, an inspection apparatus, or the like.

In this case, when the shape of the light flux passing area outside the test area on the substrate is an annular shape, the test area can be illuminated isotropically with a uniform illuminance distribution. Further, when the region to be inspected on the substrate is arranged substantially on the same plane as the front focal plane of the second illumination optical system, the light flux passage region is critically critical in the first illumination optical system. By illuminating, almost Koehler illumination is realized, and the influence of unevenness in the luminance distribution of the light source (secondary light source) is reduced. At this time, if the shape of the light flux passage area is a ring-shaped zone, the ring-shaped Koehler illumination is obtained.

Further, a third illumination optical system for illuminating the area to be inspected on the substrate from the objective lens side thereof with the illumination light from the light source of a predetermined shape is provided, and the optical member of the first illumination optical system and the first illumination optical system are provided. When at least a part of the three illumination optical systems is shared with the optical member, the first illumination optical system and the second illumination optical system of the present invention constitute a transmissive illumination system, and the third illumination optical system is This is an epi-illumination system, and some of the optical members of the epi-illumination system and the transmissive illumination system are made common. Therefore, there is an advantage that an object can be illuminated and an image thereof can be formed with either of the epi-illumination and the transmitted illumination with a simple configuration.

[Brief description of the drawings]

FIG. 1A is a partially cutaway view showing a first embodiment of an observation apparatus according to the present invention, and FIG.
It is a front view which shows 2 C of ejection openings in (a).

FIG. 2 is a partially cutaway configuration diagram showing a modification of the first embodiment.

FIG. 3A is a partially cutaway configuration diagram showing a second embodiment of the present invention, and FIG. 3B is an injection port 2 in FIG. 3A.
FIG. 3C is a front view showing C, and FIG. 3C is a front view showing the ejection port 2D in FIG.

FIG. 4A is a partially cutaway view showing a third embodiment of the present invention, and FIG. 4B is an injection port 2 in FIG. 4A.
FIG. 4C is a front view showing C, and FIG. 4C is a front view showing the injection port 2E in FIG. 4A.

FIG. 5 is a partially cutaway view showing an example of an observation apparatus including a conventional transillumination system and epi-illumination system.

[Explanation of symbols]

 1C, 1D, 1E Optical fiber bundle 2C, 2D, 2E Ejection port 8 Substrate 9 Object to be inspected 10 First objective lens 11 Aperture stop 13 Second objective lens 14 Image sensor 21 Relay lens 22 Reflective condenser lens 23 Luminous flux passage area 25 Condenser lens 26 Reflective diffusion plate 28 Field of view prism

Claims (4)

[Claims] 1. An image forming apparatus for forming an image of an object to be inspected, comprising: an illumination optical system for illuminating an object to be inspected, which is supported by a light-transmissive substrate; An imaging optical system including: a first illumination optical system that illuminates a light flux passing region outside the test region on the substrate from the objective lens side with illumination light, A second illumination optical system that includes a reflecting member that is arranged so as to face the objective lens with respect to the substrate, and that reflects the illumination light that has passed through the light flux passing region outside the test region and focuses it on the test region. An observing device comprising: 2. The observation device according to claim 1, wherein the light flux passage region outside the region to be inspected on the substrate has an annular shape. 3. The observation device according to claim 1, wherein the region to be inspected on the substrate is arranged on substantially the same plane as a front focal plane of the second illumination optical system. An observation device characterized by the above. 4. The observation apparatus according to claim 1, 2, or 3, wherein the illumination light from a light source having a predetermined shape epi-illuminates the test area on the substrate from the objective lens side. An observation apparatus comprising an optical system, wherein at least a part of the optical member of the first illumination optical system and the optical member of the third illumination optical system are made common.