JPH1070069A - Dust detecting system for semiconductor aligner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple dust detecting system for a semiconductor aligner, which can detect presence or absence of dust on a substrate holding means or a substrate and detect a dust presence position and can localizedly clean the aligner on the basis of its detected result. SOLUTION: Such a flat plate made of having a predetermined flatness and allowing light permission therethrough as an optical flat 1 is contacted with a substrate holding means 2, so that a laser beam oscillated and emitted in and from a laser light source 4 is illuminated toward the substrate holding means 2. When a dust 3 is deposited on the substrate holding means 2, this causes generation of a gap between the optical flat 1 and substrate holding means 2, whereby an operator can observe interference fringes. The interference fringes are detected by a photoelectric converting element 6, displayed on a monitor 7, and processed by an image processor 8 to thereby judge a dust presence position. On the basis of its detected result, a dust removing means is moved to the dust presence position to clean the position localizedly and positively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor manufacturing apparatus,
More particularly, the present invention relates to a dust detection apparatus for detecting dust or foreign matter attached to a substrate holding means for holding a substrate such as a wafer in a semiconductor exposure apparatus.

[0002]

2. Description of the Related Art In a semiconductor exposure apparatus for manufacturing semiconductors, light from a light source irradiates an exposure mask.
An image of the irradiated mask pattern is projected onto a photoresist on a substrate such as a wafer and exposed.

As the miniaturization and high integration of semiconductor elements progress, a high-precision semiconductor exposure apparatus is required, and even in a substrate holding apparatus for holding a substrate such as a wafer, the surface of the substrate holding surface in contact with the substrate is required. Are formed with a high flatness to correct the flatness of the substrate adsorbed on the flatness. When manufacturing an LSI, it is necessary to expose several types of mask patterns on the substrate, and another type of mask pattern is exposed at the same position on the same substrate. The exposure is performed after positioning the alignment mark of the mask and the alignment mark of the mask.

[0004] When dust or foreign matter adheres to the substrate holding means, the substrate (wafer) becomes convex due to the dust or the like, and the flatness is locally deteriorated. Further, in this case, a position shift occurs in the in-plane direction of the wafer in a portion which is convex due to adhesion of dust or the like. In this regard, K. Simon, H.-U. Scheunemann, H.-L. Huber /
"SPIE Vol. 1924" by F. Gabeli (1993)
pp. According to 282 to 289, it has been found that when a 3 μm spacer is present between the wafer (4 inches) and the substrate holding means, the double exposure causes a displacement of 100 nanometers. Therefore, there has been a problem that such a displacement during exposure or alignment adversely affects overlay (overlay) accuracy.

As a means for solving such a problem, as disclosed in Japanese Patent Application Laid-Open No. 5-75286, there is a method for detecting a foreign substance on a wafer and a substrate holding means prior to exposure. An exposure apparatus is known. The foreign matter detecting means in this conventional exposure apparatus is shown in FIG.
As shown in FIG. 1, a laser light source 101 for generating a laser beam for detecting a foreign substance, and a beam splitter 102
And a reflection mirror 104 rotatable about a rotation axis, and a photoelectric conversion element 103 for detecting scattered light reflected by the foreign matter. The laser light oscillated from the laser light source 101 is supplied to the beam splitter 102 and the reflection mirror. Via the wafer 104, the wafer 106 is irradiated horizontally with respect to the back surface of the wafer 106 or the surface of the wafer chuck 107 at the inspection position. In this irradiation, the reflecting mirror 104 is rotated by a rotation axis, or the wafer 106 and the wafer are handled by a wafer handling mechanism. By moving the chuck 107 horizontally, the laser beam is scanned over the entire inspection surface, and when foreign matter is attached,
Laser light is scattered by the foreign matter, and the scattered light is detected by the photoelectric conversion element 103 via the reflection mirror 104 and the beam splitter 102, thereby detecting the foreign matter.

[0006]

However, according to the above prior art, there are the following unsolved problems.

[0007] The size of the dust is 0.1 μm to several μm.
There are various things on the device, up to a size of the order of m. However, the flatness of the substrate holding means for holding the wafer is, for example, about 0.5 μm in a holding means of 6 inches, so that the laser light is reflected on the edge of the vacuum groove or the like of the substrate holding means to cause erroneous detection. Could be done. Further, since the wafer has a warp of the order of 10 μm, it is difficult to irradiate the laser beam in a direction perpendicular to the wafer surface.

Further, in order to determine at which position on the inspection surface dust is attached, it is necessary to scan with laser light from different orthogonal directions.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned unsolved problems of the prior art, and realizes detection of dust and foreign matters by a simple apparatus in a semiconductor manufacturing apparatus, particularly, a semiconductor exposure apparatus. Further, it is another object of the present invention to provide a dust detection device capable of detecting where dust is present on a surface to be inspected, such as a substrate holding means, and performing intensive cleaning.

[0010]

In order to achieve the above object, a dust detection apparatus in a semiconductor exposure apparatus according to the present invention comprises:
A dust detection means for contacting a flat plate with the substrate holding means, detecting interference fringes generated between the substrate holding means and the flat plate, and determining the position of dust adhering to the substrate holding means based on the interference fringes; It is characterized by.

Further, the dust detection apparatus in the semiconductor exposure apparatus according to the present invention superimposes flat plates with a deformable medium interposed in the substrate holding means, detects interference fringes generated between the deformable medium and the flat plate, and detects the interference fringes. And a dust detection device for determining the position of the dust attached to the substrate holding means.

Further, the dust detection device in the semiconductor exposure apparatus of the present invention contacts a flat plate with the substrate holding means, detects the deformation state of the flat plate by interference fringes, and determines the position of the dust adhering to the substrate holding means. It is characterized by including a dust detection means for determining.

Further, the dust detection apparatus in the semiconductor exposure apparatus according to the present invention is provided with means for adsorbing a substrate on a flat plate, and adsorbing the substrate on the flat plate to detect interference fringes generated between the substrate and the flat plate. The apparatus is further provided with dust detection means for judging the position of dust attached to the substrate based on interference fringes.

Further, in the dust detection apparatus in the semiconductor exposure apparatus of the present invention, the flat plate has a predetermined flatness,
A material that transmits light, or a material that has substantially the same rigidity as a substrate such as a wafer, transmits light, and has a predetermined flatness;
Alternatively, it is preferably an optical flat.

Further, it is preferable that the dust detecting device in the semiconductor exposure apparatus of the present invention includes dust removing means capable of intensively cleaning the position where dust is present.

The dust detector in the semiconductor exposure apparatus according to the present invention is provided with a high-pressure gas blowing means, and the high-pressure gas blowing means blows a high-pressure gas to a position where dust is present to remove the dust. In the high-pressure gas blowing means, it is preferable to provide a suction port around the high-pressure gas blowing port.

The semiconductor exposure apparatus of the present invention is characterized in that it has a dust detection apparatus as described above and an exposure means for exposing the substrate held by the substrate holding means.

[0018]

According to the dust detecting device in the semiconductor exposure apparatus of the present invention, a flat plate such as an optical flat which transmits light with good flatness is superimposed on the substrate holding means, and a laser beam is applied to the substrate holding means to detect the presence of dust. The interference fringes generated can be detected to determine the presence and the position of the dust, and for a substrate holding means such as a pin chuck having a reduced contact area with the substrate, it is almost equivalent to a substrate such as a wafer. The presence and location of dust can be determined by analyzing the deformation state of the deformation medium with interference fringes with a rigid deformation medium interposed.

Further, by providing a dust removing means capable of intensively cleaning the determined position of the dust, the dust can be removed reliably and promptly.

Further, means for adsorbing the substrate to a flat plate such as an optical flat is provided, and the substrate is adsorbed to the flat plate by the adsorbing means, and a laser beam is irradiated from the opposite side to adhere the substrate to the back surface of the substrate. It is possible to detect garbage and its location.

[0021]

Embodiments of the present invention will be described with reference to the drawings.

A dust detection device for detecting dust and foreign matter according to the present invention will be described with reference to FIG. The dust detection device includes a laser light source 4 that generates a laser beam that irradiates a surface to be inspected to detect dust, a beam splitter 5, a photoelectric conversion element 6 that detects interference fringes through the optical flat 1, and a monitor. 7 and an image processing device 8 for performing image processing on the detected interference fringes. When inspecting the presence of dust on the surface of the substrate holding means 2, first, the optical flat 1 is loaded on the substrate holding means 2, and the laser light oscillated from the laser light source 4 passes through the beam splitter 5 to the inspection position. Irradiate the surface of the substrate holding means 2 through a certain optical flat 1. Now, as shown in FIG. 1, when dust 3 adheres to the substrate holding means 2, a gap is generated between the substrate holding means 2 and the optical flat 1 due to the presence of the dust 3, and interference occurs. Streaks are observed.
Here, the substrate holding means 2 and the optical flat 1
Is the gap between the laser light source 4 and λ, the number N of interference fringes generated at this time is N = d /
(Λ / 2). This interference fringe forms an image on the photoelectric conversion element 6 through the beam splitter 5 and the lens 9, and the interference fringe as shown in FIG.
Here, the adhesion position of the dust 3 is located at the center of the circle with the smallest interference fringe on the monitor 7, and the adhesion position of the dust on the substrate holding means 2 can be determined. Further, this image can be processed by the image processing device 8 to automatically determine the position on the substrate holding means 2. Also, in order to facilitate the analysis of interference fringes, a mechanism (not shown) is used to analyze the interference fringes by minimizing the number of interference fringes by tilting the substrate holding unit integrally with the optical flat. Is also possible.

The optical flat 1 is stored in a stock portion (not shown) of the optical flat installed in the semiconductor exposure apparatus. When dust is detected, the stock portion is loaded using loading means (not shown). Can be loaded onto the substrate holding means 2. As the loading means for the optical flat, a loading means dedicated to the optical flat may be attached to the semiconductor exposure apparatus, or may also serve as a holding means for transporting the substrate.

In loading the optical flat onto the substrate holding means, if the substrate holding means is arranged horizontally as shown in FIG. 1, the optical flat is simply placed on the substrate holding means. However, if the substrate holding means is arranged vertically, the optical flat cannot be simply placed, so that the optical flat is adsorbed to the substrate holding means, or the optical flat is attached to the substrate holding means. It is necessary to carry out the inspection while keeping the state in contact.

Note that the optical flat 1 used for dust detection here is an example for detecting interference fringes.
Instead of the optical flat, a flat plate having good flatness and transmitting light can be used. The flatness of a flat plate such as an optical flat is preferably 2λ or less.

Further, light having coherence required for causing interference is used. For example, a laser beam, which is a coherent beam, is used.
e-Ne laser light (wavelength 632.8 nm) is used. In addition, when light of various wavelengths, such as sunlight or electric light, is used, monochromatic light is used by using an interference filter.

Then, the laser beam is expanded by using a beam expander in front of the beam splitter 5, and
The entire surface of the substrate holding means 2 may be irradiated at one time, or the laser light may reach the entire surface by scanning the substrate holding means 2 without expanding the laser light.

In a substrate holding means having a vacuum groove or the like, interference fringes are also generated due to the presence of the vacuum groove or the like, and it is difficult to detect and judge dust immediately. The state of the substrate holding surface can be determined by inputting the groove information into a computer in advance, performing image processing on the groove information, and performing processing such as joining interference fringes. Further, since the substrate holding means is not a perfect plane but has a slight flat warpage, the optical flat is brought into contact with the substrate holding means in advance, the warpage of the substrate holding means is detected, and the detected substrate holding means is detected. Information may be input to a computer so that the warpage information of the substrate holding means can be subtracted from the information at the time of detection of dust when dust is attached, so that the information can be analyzed.

In the above description, detection of dust on the substrate holding means (wafer chuck) for holding a substrate at the time of exposure has been described. However, the present invention is not limited to the substrate holding means (wafer chuck). The present invention can also be applied to detection of dust or the like on a holding means, for example, a hand which is a holding means for loading / unloading. That is, the optical flat is attracted to the hand, moved to the above-described dust detection position, and thereafter, whether or not dust is attached to the hand can be detected by a similar method.

By detecting the dust as described above, it is possible to identify the position of the dust on the substrate holding means 2 so that the position of the dust holding on the substrate holding means 2 is intensively cleaned. This makes it possible to reliably remove dust. The dust is removed after the optical flat 1 is removed from the substrate holding means 2 and placed in a stock portion of the optical flat.

Next, a method of removing the detected dust will be described with reference to FIGS. FIG. 2 is a schematic diagram of a dust removal unit, and FIG. 3 is a schematic diagram showing a mode of removing dust using the dust removal unit. The dust removal unit 18 includes a high-pressure gas blowing port 10 provided at the center of the pipe and a suction port 11 provided therearound.
The suction port 11 communicates with a dust storage unit (not shown).
The refuse removing member 1 in which the refuse removing unit 18 is assembled.
9, the dust removing unit 18 is moved closer to the dust attaching position by moving the dust removing unit 18 to the detected dust attaching position on the substrate holding means 2 as shown in FIG. Then, the high-pressure gas is blown from the high-pressure gas blowing port 10 toward the dust attaching position, and the dust 3 is removed from the substrate holding means 2 by the blowing of the high-pressure gas. Simultaneously, by removing the vacuum from the suction port 11, the removed dust 3 is sucked into the suction port 11,
It is stored in the garbage storage unit. Thus, debris removal can be performed intensively. Then, after the dust is removed, the optical flat 1 can be loaded onto the substrate holding means 2 again to check whether the dust has been surely removed.

In the refuse removal unit 18, if the pump for vacuuming the suction port 11 is also used as a pump for evacuating the chamber or a pump for holding the substrate, the apparatus can be constructed at low cost. Can be. As the high-pressure gas to be blown, it is preferable to use the same gas as the atmosphere of the exposure apparatus. When the exposure is performed in the air, Air is used. When the exposure is performed in the He atmosphere, He is used. Is good. By doing so, it is not necessary to change the atmosphere inside the chamber of the exposure apparatus. Further, with respect to the purity of the gas, by using a gas having the same purity, it is not necessary to newly evacuate the chamber even if the dust is removed in the purity controlled chamber.

Since the dust is removed by such a dust removing unit, the holding surface of the substrate holding means 2 is not damaged and its flatness is not deteriorated, and new dust is generated by friction. Nothing is gone. Therefore, it is possible to quickly remove the debris by intensively cleaning the position where the detected debris is attached without damaging the holding surface of the substrate holding means. Cleaning can be performed without reattaching to the surface and without worrying about the generation of new dust.

The method of removing dust is not limited to the above example. (1) The fine particle adsorbing member is brought into contact with the substrate holding surface, and the dust is attached to the fine particle adsorbing member. (2) Pass through the rotating brush with the cleaning liquid. (3) The air containing the ionized particles is jetted to combine the foreign matter with the ion molecules. Waste can also be removed by such methods.

Next, the detection of dust when a pin chuck is used as the substrate holding means will be described with reference to FIG. In the substrate holding means, a pin chuck has been devised to reduce the influence of dust, and this pin chuck reduces the contact area between the substrate holding means and the substrate in order to reduce the influence of dust. The probability that dust adheres to the substrate holding means is reduced, and the substrate holding surface has a very large number of irregularities. The area ratio between the convex portions and the concave portions is, for example, a ratio of 1: 9. . The convex portion is a contact portion with the substrate, and the concave portion is a non-contact portion. The dust adhering to the non-contact portion does not deteriorate the flatness of a substrate such as a wafer and does not cause problems such as displacement in an in-plane direction.

In such a substrate holding means having an extremely small contact area with the substrate such as the pin chuck, FIG.
Since it is difficult to join the interference fringes by the image processing described in relation to the above, dust is detected by the following method.

In FIG. 4, the substrate holding means is a pin chuck 2 and shows a state where dust 3 adheres to the pins. Even if the optical flat 1 is brought into direct contact with the pin chuck 2 as in the previous embodiment in a state where the dust 3 adheres, it is difficult to analyze the interference fringes. Therefore, in this embodiment, a super flat wafer 20 having a small thickness unevenness on a double-side polished wafer is used as a deformation medium, and the super flat wafer 20 is sucked to the pin chuck 2. As a result, the super flat wafer 20 is affected by the dust 3 and is deformed as shown in FIG. Then, the optical flat 1 is brought into contact with the surface of the super flat wafer 20 by loading means (not shown). After that, the laser light is applied to the optical flat 1 similarly to the dust detection apparatus of the previous embodiment.
The super flat wafer 20 is irradiated from the side, and interference fringes generated between the optical flat 1 and the super flat wafer 20 are read. By doing so, the deformation state of the super flat wafer under the influence of dust can be analyzed by interference fringes, and the presence of dust and the position where dust is attached can be detected.

Here, in place of the super flat wafer used as the deformable medium, a material having the same rigidity as a substrate such as a wafer, a small thickness unevenness, a light-impermeable material, and a large surface reflectance is used. Can also be used. Also, the optical flat is only an example when detecting interference fringes, and a flat plate having good flatness and transmitting light can be used instead of the optical flat.

As described above, this embodiment is particularly useful when a large number of grooves and recesses are present on the surface of the substrate holding means. Can be detected.

In the above-described first and second embodiments, after the substrate is held by the substrate holding means by suction, the substrate is irradiated with a laser beam through a flat plate such as an optical flat, so that the dust is removed. Not only the presence of dust, but also the flatness of the board with dust in between, so that not only the presence and size of dust, but also how much it affects the flatness of the board, including the deformation of dust during suction Can be confirmed. Therefore, it is possible to remove dust only when the flatness of the substrate is adversely affected.

Further, in the dust detection apparatus, a flat plate having good flatness and transmitting light and having substantially the same rigidity as a substrate such as a wafer is used in place of the optical flat. When polymerized or adsorbed on the substrate, due to the influence of dust on the substrate holding means,
The flat plate itself deforms. By irradiating a laser beam in this state in the same manner as in the above-described embodiment, interference fringes corresponding to the deformed state can be observed, and the presence of dust and the position where dust is attached can be detected by the interference fringes. .

By the way, in the above-mentioned embodiment, dust on the back surface of the substrate could not be detected, but the embodiment shown in FIGS. 5 and 6 makes it possible to detect dust on the back surface of the substrate. FIG. 5 shows a vacuum system for adsorbing a substrate formed in an optical flat in a dust detection device for the back surface of the substrate. A vacuum port 22 (four in FIG. 5) is provided on one surface of the optical flat 21, and this surface is used as a surface for adsorbing the substrate 27, and these vacuum ports 22 are connected to a vacuum pipe 23. Each of the vacuum pipes 23 is connected to a distributor 24, and further connected to a vacuum pump 26 via a valve 25. The optical flat 21 is provided with a vacuum port 22 and a vacuum pipe 23.
By wrapping in the final step after processing such as connection ports for the substrate, sufficient flatness of the substrate suction surface is ensured.

Thus, the substrate 27 is placed on the substrate suction surface of the optical flat 21 by operating the pump 26 and opening the valve 25, thereby placing the substrate 27 on the substrate suction surface of the optical flat 21. Here, the substrate 27 follows the flatness of the substrate suction surface of the optical flat 21 that has been processed with high precision, and the surface of the substrate also has a flatness close to the optical flat. Then, as shown in FIG. 6, laser light is irradiated from the back surface of the optical flat 21 to detect dust on the back surface of the substrate 27. The laser light source 4, the beam splitter 5, the lens 9, the photoelectric conversion element 6, the monitor 7, and the image processing device 8 have the same configurations as those described in relation to the first embodiment. Therefore, when dust is attached to the back surface of the substrate 27 by irradiating the back surface of the optical flat 21 with the laser beam, the substrate 27
It is adsorbed at a distance corresponding to the amount of dust, and an interference fringe corresponding to this distance can be detected. Thus, in this embodiment, it is possible to determine the presence or absence of dust on the back surface of the substrate 27 and the position where dust is attached.

Further, in this embodiment, if dust adheres to the back surface of the substrate 27 at a position corresponding to the position of the vacuum opening 22 of the optical flat 21, the dust cannot be detected. By moving the substrate 27 and the optical flat 21 relative to each other so as to change the relative position, and re-adsorbing, the dust can be detected in all the necessary regions of the substrate.

In this embodiment, it is preferable to periodically clean the optical flat 21 so that no dust remains on the substrate suction surface.

Also, in this embodiment, the optical flat is only an example when detecting interference fringes, and any flat plate having good flatness and transmitting light can be used in place of the optical flat. is there.

Further, by using the dust detection apparatus of this embodiment, all the substrates can be inspected before exposure, and the substrate having dust attached to the back surface of the substrate can be collected.

[0048]

Since the present invention is constructed as described above, a flat plate having good flatness such as an optical flat is superimposed on the substrate holding means, and interference observed by irradiation of laser light is obtained. Since the presence of dust and the position of the dust attached to the substrate holding means can be determined by the stripes, the position where the dust is attached can be intensively cleaned, and the dust can be removed reliably and promptly. Can be. Further, dust can be detected and removed with a simple device.

Further, dust on the back surface of a substrate such as a wafer can be detected as well as the substrate holding means.

Further, not only the adhesion of the dust but also the flatness of the dust sandwiched between the substrate and the substrate holding means can be confirmed. Thus, it is possible to confirm how much influence is exerted on the flatness of the substrate, and it is also possible to remove dust only when the flatness is adversely affected.

As described above, according to the present invention, when dust adheres to the substrate holding means or the like or when the flatness of the substrate is adversely affected, the detected adhesion position of the dust is concentrated. Since cleaning can be performed, dust can be detected and removed reliably and promptly by simple means.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a dust detection device of the present invention.

FIG. 2 is a schematic diagram of a dust removal unit of the present invention.

FIG. 3 is a schematic view showing an embodiment of the present invention for removing dust.

FIG. 4 is a schematic diagram showing a second embodiment of the dust detection device of the present invention.

FIG. 5 is a schematic diagram showing a vacuum system for adsorbing an optical flat substrate in a third embodiment of the dust detection apparatus of the present invention.

FIG. 6 is a schematic view showing a third embodiment of the refuse detection device of the present invention.

FIG. 7 is a schematic diagram showing a conventional foreign matter detection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical flat 2 Substrate holding means 3 Garbage 4 Laser light source 6 Photoelectric conversion element 7 Monitor 8 Image processing apparatus 10 High-pressure gas blowing port 11 Suction port 18 Dust removal unit 19 Dust removal member 20 Super flat wafer (deformation medium) 21 Optical flat ( Substrate holding means) 22 Vacuum port 27 Substrate

Claims (19)

[Claims] 1. A garbage detector for contacting a flat plate with a substrate holding means to detect an interference fringe generated between the substrate holding means and the flat plate, and for detecting the position of dust attached to the substrate holding means based on the interference fringe. A dust detection device in a semiconductor exposure apparatus, characterized by comprising means. 2. A flat plate is superimposed on a substrate holding means with a deformable medium interposed therebetween, interference fringes generated between the deformable medium and the flat plate are detected, and the position of dust adhering to the substrate holding means is detected by the interference fringes. A dust detection device in a semiconductor exposure apparatus, comprising a dust detection device for determining. 3. A dust detecting means for contacting a flat plate with the substrate holding means, detecting a deformed state of the flat plate by interference fringes, and judging a position of dust adhering to the substrate holding means. Detection device in semiconductor exposure equipment. 4. The dust detecting apparatus according to claim 1, wherein the flat plate is made of a material having a predetermined flatness and transmitting light. 5. The flat plate according to claim 1, wherein the flat plate is made of a material having substantially the same rigidity as a substrate such as a wafer, transmitting light, and having a predetermined flatness. Garbage detector in semiconductor exposure equipment. 6. The dust detecting apparatus in a semiconductor exposure apparatus according to claim 1, wherein the flat plate is an optical flat. 7. A deformable medium is a material having substantially the same rigidity as a substrate such as a wafer and impermeable to light, a material having a large reflectivity and an irregular thickness, and a flat plate transmitting light. 3. The dust detecting device according to claim 2, wherein the dust detecting device is a material having a predetermined flatness. 8. A flat plate is provided with means for adsorbing a substrate, and the substrate is adsorbed on the flat plate to detect interference fringes generated between the substrate and the flat plate. A dust detection device in a semiconductor exposure apparatus, comprising dust detection means for determining. 9. The dust detecting apparatus in a semiconductor exposure apparatus according to claim 8, wherein light for dust detection is emitted from the opposite side of the flat plate to the substrate suction surface. 10. The dust detecting apparatus according to claim 8, wherein the flat plate is made of a material having a predetermined flatness and transmitting light. 11. The dust detecting apparatus according to claim 8, wherein the flat plate is an optical flat. 12. A dust detecting apparatus in a semiconductor exposure apparatus according to claim 1, further comprising dust removing means capable of intensively cleaning the position where dust is present. 13. The apparatus according to claim 1, wherein high-pressure gas blowing means is provided, and the high-pressure gas blowing means blows high-pressure gas to a position where dust is present to remove dust. A dust detection device in the semiconductor exposure apparatus according to claim 1. 14. The dust detecting apparatus in a semiconductor exposure apparatus according to claim 13, wherein the same gas as the exposure atmosphere is used as the high-pressure gas and the gases have the same purity. 15. A dust detecting apparatus in a semiconductor exposure apparatus according to claim 13, wherein the high-pressure gas blowing means has a suction port provided around the high-pressure gas blowing port. 16. The method according to claim 1, wherein a stock portion of a flat plate is provided.
13. A dust detection device in a semiconductor exposure apparatus according to item 9. 17. The dust detecting apparatus according to claim 16, further comprising a flat plate loading means. 18. A dust detecting apparatus in a semiconductor exposure apparatus according to claim 16, wherein the loading of the flat plate is performed by a loading means for transporting the substrate. 19. A semiconductor exposure apparatus comprising: the dust detection apparatus according to claim 1; and exposure means for exposing a substrate held by the substrate holding means.