JP2011120993A - Foreign matter removing device for substrate and method for removing foreign matter for substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foreign matter removing device for substrate with capability to successfully remove organic foreign matter sticking to the surface of a substrate in a manufacturing process, without leaving tailings unremoved and injuring the surface of the substrate, as well as a method for removing the foreign matter for substrates. <P>SOLUTION: The organic foreign matter α is specified by observing the surface of the substrate BS, and the positions of the foreign matter removing device for substrates and the organic foreign matter α on the substrate BS are registered. Next, a photocatalytic tape PHT is made to descend and a photocatalytic layer of the photocatalytic tape PHT is contact-bonded to the organic foreign matter α. After that, the light is shined from the opposite side, to the surface which is contact-bonded to the organic foreign matter α, of the photocatalytic tape PHT by actuating a light irradiation means 400. The organic foreign matter α is photooxidized by the action to absorb the light by the photocatalyst and consequently, the organic foreign matter α is decomposed and removed, thus completing the removal of the foreign matter α. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a substrate foreign matter removing apparatus and a substrate foreign matter removing method suitable for removing foreign matter on a substrate, particularly organic foreign matter (organic foreign matter).

  For example, color filter substrates are required to be smooth with no foreign matter on the surface, but in the manufacturing process, dust or oil may adhere to the substrate surface or abnormal protrusions may occur. As a device for removing the dust, a device for polishing and removing foreign matter using a polishing tape, a device for removing the foreign matter by irradiating laser light, and the like have been put into practical use (for example, see Patent Documents 1 and 2).

JP-A-8-229797 JP 2004-325837 A

  However, in a foreign matter removing apparatus using a polishing tape or laser light, polishing scraps and laser processing scraps may remain on the substrate surface, and if the foreign matter is to be removed satisfactorily, excessive polishing and laser over-irradiation will occur. The substrate surface could be damaged.

  Accordingly, the present invention addresses such problems and is a removal device / removal method that is particularly effective for removing organic foreign matter (organic foreign matter), in which organic foreign matter (organic foreign matter) is left as debris. It is an object of the present invention to provide a substrate foreign matter removing apparatus and method which can be satisfactorily removed without damaging the substrate surface.

In order to achieve the above object, a substrate foreign matter removing apparatus according to the present invention is a device for removing foreign matter on a substrate, comprising a photocatalyst having a base coated with a photocatalyst, the photocatalyst and the substrate. Moving means for moving at least one of the photocatalyst layers in contact with the foreign matter on the substrate, and light irradiation for irradiating light on the photocatalytic layer in contact with the foreign matter. Means.
In such a configuration, when light is irradiated while the photocatalyst layer is in contact with the foreign matter, the organic foreign matter is selectively decomposed and removed by a photooxidation reaction by the photocatalyst layer.

Here, the base material can transmit light emitted by the light irradiation unit, and the light irradiation unit can emit light toward the surface of the photocatalyst on the base material side.
In such a configuration, light irradiated toward the photocatalyst body from the side opposite to the surface facing the foreign material (substrate) passes through the base material and reaches the photocatalyst layer in contact with the foreign material.

The photocatalyst body may be a photocatalyst tape in which a tape-like base material is coated with a photocatalyst, and a transfer means for transferring the photocatalyst tape through a region where the moving means contacts the foreign matter may be provided.
In such a structure, the part used for removal of a foreign material can be replaced by transferring the photocatalytic tape.

Here, every time the light irradiation means performs irradiation, the transfer means retracts the light irradiated portion of the photocatalytic tape, and the moving portion contacts the non-irradiated portion of the photocatalytic tape with the foreign matter. Can be made.
In such a configuration, the part of the photocatalyst tape that has been used for the photo-oxidation reaction of the foreign matter by light irradiation is retracted after removing the foreign matter, and at the same time, the part that has not yet been irradiated with light (unused part). Then, it is transferred to a region where it is brought into contact with the foreign matter, and the next foreign matter removal is performed using the subsequent portion of the portion irradiated with light this time.

Further, the moving means may be configured to bring the photocatalytic tape stretched between a pair of rotating shafts into contact with the foreign matter on the substrate.
In such a configuration, the photocatalyst tape stretched between the pair of rotating shafts is brought into close contact with the substrate surface, whereby the photocatalyst layer of the photocatalyst tape can be brought into contact with the foreign matter on the substrate.

Further, the moving unit may be configured to move at least one of the pair of rotating shafts in a direction in which the photocatalytic tape is separated from or in contact with the substrate.
In such a configuration, by moving at least one of the pair of rotating shafts in parallel, the transfer path of the photocatalytic tape is changed, and the photocatalytic tape can be brought into contact with and separated from the substrate along with the parallel movement.

Moreover, the tape-shaped base material of a photocatalyst tape can be formed with an organic material, and the protective layer formed with the inorganic material can be provided between this tape-shaped base material and a photocatalyst layer.
In such a configuration, the photocatalytic tape includes a protective layer formed of an inorganic material between the tape-shaped substrate formed of an organic material and the photocatalyst layer, so that the photocatalytic layer and the tape-shaped substrate are in direct contact with each other. In other words, it is possible to avoid that the tape-shaped base material is photooxidized by the photocatalyst layer and the tape base material is decomposed.

The substrate foreign matter removing method according to the present invention is a method for removing foreign matter on a substrate, wherein the photocatalyst layer of a photocatalyst body having a base material coated with a photocatalyst is brought into contact with the foreign matter on the substrate, and the foreign matter is contacted. The photocatalyst layer is irradiated with light.
In such a configuration, when light is irradiated while the photocatalyst layer is in contact with the foreign matter, the organic foreign matter is selectively decomposed and removed by a photooxidation reaction by the photocatalyst layer.

  According to the substrate foreign matter removing apparatus and method according to the present invention, the organic foreign matter is oxidized to water or carbon dioxide by the photooxidation reaction by the photocatalyst and decomposed, so that organic foreign waste remains on the substrate surface after removal. In addition, since the organic foreign matter is decomposed by the catalytic reaction, the substrate is not damaged by removing the foreign matter.

It is a front view which shows the foreign material removal apparatus for substrates in embodiment of this invention. It is a side view which shows the foreign material removal apparatus for substrates in embodiment of this invention. It is a perspective view which shows the laminated structure of the photocatalyst tape used with the foreign material removal apparatus for substrates in embodiment of this invention. It is process drawing which shows the operation | movement procedure of the foreign material removal in the board | substrate foreign material removal apparatus of embodiment of this invention.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a front view of a substrate foreign matter removing apparatus 100 according to the present invention, and FIG. 2 is a side view thereof.
The substrate foreign matter removing apparatus 100 shown in FIGS. 1 and 2 removes the organic foreign matter α adhering to the surface of a flat substrate BS (for example, a color filter substrate) placed on a table 200 using a photocatalytic tape PHT. Device.

  The substrate foreign matter removing apparatus 100 includes a moving unit 300 that moves the photocatalytic tape PHT in a direction in which the substrate BS is separated from and contacting the substrate BS (Z-axis direction), and light (photocatalytic wavelength light of the photocatalyst, for example, toward the photocatalytic tape PHT). A light irradiating means (light source) 400 such as a lamp or a semiconductor laser, and a transfer means 500 for transferring the photocatalytic tape PHT via the moving means 300.

The substrate foreign matter removing apparatus 100 having the above means is mounted on an X-axis slider (base plate) 600, and the X-axis slider 600 is in the left-right direction (X-axis direction) in FIG. The X-axis frame is attached to the table 200 so as to be movable in the Y-axis direction, the X-axis frame is moved in the Y-axis direction with respect to the table 200, and the X-axis slider 600 is moved. The movement in the X-axis direction with respect to the X-axis frame is performed by, for example, a feed screw mechanism that is operated by rotation of a drive motor.
That is, the substrate foreign matter removing apparatus 100 is configured to be movable on a plane (XY plane) parallel to the table 200 and can be moved directly above the foreign matter α of the substrate BS placed on the table 200. It is like that.

  The moving means 300 is a pair of guide rails 301 and 301 provided along the Z-axis (vertical direction) with respect to the X-axis slider 600, and is engaged and supported by the guide rails 301 and 301 in the Z-axis direction. A movable pressing slider 302 and an X-axis slider 600 are supported along the Z-axis (vertical direction) and screwed to a ball nut (not shown) fixed to the rear surface (rear surface) of the pressing slider 302. A ball screw 303, a drive motor 304 that rotates the ball screw 303 about its axis, an encoder 305 that detects the rotation of the drive motor 304, and the pressing slider 302 are supported so as to be rotatable about the Y-axis direction. And a pair of rotating shafts 306 and 306 disposed at the same height in the Z-axis direction and spaced apart by a predetermined distance Wx in the X-axis direction.

According to the moving means 300, when the ball screw 303 is rotated by the drive motor 304, the pressing slider 302 moves in parallel along the Z-axis direction. As the pressing slider 302 moves, the pair of pairs The rotary shafts 306 and 306 move in parallel with each other in the Z-axis direction, in other words, in the direction of separating from and contacting the substrate BS.
The light irradiation means (light source) 400 emits light downward with the optical axis as the Z-axis direction, and the width of the photocatalytic tape PHT in the Y-axis direction (in other words, the width direction of the photocatalytic tape PHT). The light irradiating means (light source) 400 moves up and down as the pressing slider 302 moves in the Z-axis direction so that the optical center is the optical axis.

  The transfer means 500 is fitted to rotary shafts 501 and 502 attached to the X-axis slider 600 along the Y-axis direction, a winding motor 503 for winding the photocatalyst tape PHT, and a rotary shaft 503a of the winding motor 503. A combined timing pulley 504, a timing pulley 505 fitted to the rotary shaft 502, a timing belt 506 stretched between the timing pulley 504 and the timing pulley 505, and a foreign matter fitted to the rotary shaft 501 A tape reel R1 around which a photocatalytic tape PHT used for removal is wound in advance, and a tape reel R2 that is fitted onto the rotary shaft 502 and winds up the photocatalytic tape PHT drawn out from the tape reel R1.

  Here, the region in which the pair of rotary shafts 306 and 306 move up and down is set to the lower side in the Z-axis direction than the region sandwiched between the tape reels R1 and R2 in the X-axis direction, and is pulled out from the tape reel R1. The photocatalyst tape PHT is hung on the lower side of the pair of rotating shafts 306 and 306 and wound around the tape reel R2, so that the transfer path of the photocatalyst tape PHT from the tape reel R1 toward the tape reel R2 is: The photocatalyst tape PHT extends to the substrate BS side in the middle, and is stretched approximately parallel to the surface of the substrate BS between the pair of rotating shafts 306 and 306.

FIG. 3 shows a detailed structure of the photocatalytic tape PHT.
The photocatalytic tape PHT includes a tape-like base material BL formed of an organic material (for example, polyethylene terephthalate PET or polyimide), a protective layer PL formed of an inorganic material laminated on one surface of the base material BL, and the protection It has a three-layer structure with a photocatalyst layer (photodegradable catalyst layer) PHL made of titanium oxide TiO ₂ or the like laminated on the layer PL, and the light irradiation means (light source) 400 includes the base BL and the protective layer PL. It is formed of a material that transmits the light to be irradiated (for example, ultraviolet rays). Then, the transfer means 500 is mounted so that the surface on the photocatalyst layer PHL side faces the substrate BS.

When an organic material is used for the tape-shaped substrate BL as in this embodiment, when the photocatalyst layer PHL is in direct contact with the tape-shaped substrate BL, the light irradiation means (light source) 400 is used to remove organic foreign matters. Since the tape-like base material BL is decomposed by photo-oxidation when irradiated with light, a protective layer PL made of an inorganic material is sandwiched between the tape-like base material BL and the photocatalyst layer PHL, and the photocatalyst layer The PHL and the tape-like base material BL are not in direct contact with each other.
Therefore, when the tape-like base material BL is formed of an inorganic material, the photocatalytic tape PHT can have a two-layer structure of the tape-like base material BL and the photocatalytic layer PHL without providing the protective layer PL. .

The photocatalyst layer PHL can be coated on the protective layer PL (or tape-like substrate BL) by vapor deposition, sputtering, or the like, or a coating containing a photocatalyst material may be applied and coated.
In addition, when titanium oxide is used as the material of the photocatalyst layer PHL, the absorption light shows a peak in the ultraviolet region having a wavelength of 380 nm or less, so that the light irradiated by the light irradiation means (light source) 400 may be ultraviolet light. Although it is preferable, a photocatalyst that operates in the visible light region may be used, and the wavelength of the light irradiated by the light irradiation means (light source) 400 may be in the photosensitive wavelength region of the photocatalyst to be used.
In addition, the base material BL and the protective layer PL may transmit at least 30% or more, preferably 70% or more, through which the light irradiated from the light irradiation unit (light source) 400 is transmitted.

An operation procedure for removing organic foreign matters α (such as dust and oil) on the substrate BS using the substrate foreign matter removing apparatus 100 having the above configuration will be described below with reference to FIG.
First, the tape reel R1 and the empty tape reel R2 around which the photocatalytic tape PHT is wound are fitted to the rotary shafts 501 and 502, respectively, and then the end of the photocatalytic tape PHT is pulled out from the tape reel R1, and the photocatalytic tape pulled out is pulled out. The PHT is hung on the substrate BS side of the pair of rotating shafts 306 and 306 and locked to the boss portion of the tape reel R2.
In this state, the winding motor 503 is driven to apply tension to the photocatalytic tape PHT, and the photocatalytic tape PHT is stretched between the pair of rotating shafts 306 and 306.

When the substrate foreign matter removing apparatus 100 is prepared as described above, then, for example, the surface of the substrate BS is photographed by the photographing means fixed to the X-axis slider (base plate) 600, and an electric image signal from the photographing means is obtained. For example, the image of the surface of the substrate BS is displayed on a display device provided on the console of the removal device 100, for example.
The operator identifies an organic foreign substance α on the substrate BS by observing an image (enlarged image) of the surface of the substrate BS displayed on the display device, and the optical axis of the imaging means is centered on the organic foreign substance α. Are moved together on the XY plane so as to coincide with each other (see FIG. 4A).

Here, when the imaging unit is fixed to the X-axis slider (base plate) 600, the deviation between the optical axis of the imaging unit and the center position of the region where the substrate foreign matter removing apparatus 100 removes the organic foreign matter is known. From the state where the optical axis of the imaging means coincides with the center of the organic foreign matter α, the X-axis slider for making the center position of the region where the substrate foreign matter removing device 100 removes the organic foreign matter coincide with the center of the organic foreign matter α. The amount of movement of the (base plate) 600 is known.
Therefore, the substrate foreign matter removal is performed by moving the X-axis slider 600 (the photographing means and the substrate foreign matter removing apparatus 100) by the known movement amount from a state in which the optical axis of the imaging means coincides with the center of the organic foreign matter α. The center position of the region where the apparatus 100 removes the organic foreign matter is matched with the center of the organic foreign matter α.

The center position of the region where the substrate foreign matter removing apparatus 100 removes the organic foreign matter is substantially the center in the width direction of the photocatalytic tape PHT in the Y-axis direction, and substantially in the middle of the pair of rotating shafts 306 in the X-axis direction. It is.
When the center position of the area where the substrate foreign matter removing apparatus 100 removes the organic foreign matter moves directly above the organic foreign matter α on the substrate BS, the pressing slider that has been retracted to the initial position on the upper side in the Z-axis direction. 302 is lowered so as to approach the substrate BS by rotating the drive motor 304, and the photocatalyst layer PHL of the photocatalyst tape PHT stretched between the pair of rotary shafts 306 and 306 is pressed against the organic foreign matter α. (See FIG. 4B).

Here, the distance from the initial position of the pressing slider 302 to the surface of the substrate BS is known, and the amount of movement (movement amount) of the pressing slider 302 can be detected by the encoder 305. Therefore, the photocatalytic layer PHL of the photocatalytic tape PHT is It is possible to accurately press the organic foreign matter α.
Note that when the pressing slider 302 (the pair of rotating shafts 306 and 306) is lowered, the tension applied to the photocatalyst tape PHT increases, so that the photocatalyst tape PHT from the tape reel R1 side is newly drawn out, and the photocatalyst. The tension applied to the tape PHT is prevented from becoming excessive.

When the photocatalyst layer PHL of the photocatalyst tape PHT is pressure-bonded to the organic foreign matter α, the light irradiation means 400 (light source) is then operated to oppose the portion of the photocatalyst tape PHT that is pressure-bonded to the organic foreign matter α (tape shape). Is irradiated with light having a preset intensity for a predetermined time (see FIG. 4C).
The intensity of the light and / or the irradiation time depends on the size of the organic foreign matter α, for example, the height of the organic foreign matter α, the area of the organic foreign matter α on the XY plane, the volume (height and area) of the organic foreign matter α, and the like. Can be changed.

The light irradiated to the substrate BL side of the photocatalytic tape PHT passes through the substrate BL and the protective layer PL and reaches the photocatalyst layer PHL, and the photocatalyst layer PHL absorbs light, so that excited electrons and holes are absorbed. However, the excited electrons move to oxygen in the air, so that the oxidation reaction by the remaining holes proceeds to oxidize the organic foreign matter α.
Oxidation by the photocatalyst layer PHL gasifies the organic foreign matter α into water, carbon dioxide, and the like, and the products resulting from these oxidative decompositions diffuse to the surroundings, thereby completing the removal of the organic foreign matter α (FIG. 4D). .

  When the removal of the organic foreign matter α is completed, the winding slider 503 is lifted while driving the winding motor 503 to wind the photocatalytic tape PHT on the tape reel R2 side. The portion of the photocatalyst tape PHT used to remove the organic foreign matter α is wound around the tape reel R2 side while the photocatalyst tape PHT is prevented from loosening. Instead, the unused portion is newly used from the tape reel R1 side. Try to send out the part.

Thereby, it is avoided that the region (light irradiation region) of the photocatalyst tape PHT used for the removal of the organic foreign matter α this time is used again for the next removal, and the unused unused newly fed out from the tape reel R1 side. The part is used for the next removal.
In order to replace the portion used for removing the organic foreign matter α, the drive of the winding motor 503 is continued even after the pressing slider 302 is raised to the upper initial position, and the photocatalytic tape PHT with respect to the tape reel R2 is continued. Can be continued, and at the same time, the unused photocatalytic tape PHT can be sent out from the tape reel R1 side.

According to the substrate foreign matter removing apparatus 100 described above, the organic foreign matter α is oxidatively decomposed and removed by the oxidizing action of the photocatalyst. Even if the light is continuously irradiated after the foreign matter is completely decomposed and removed, Irradiation does not damage the substrate BS, and the substrate BS can be prevented from being damaged while the organic foreign matter α is removed well.
Further, in the oxidative decomposition of the organic substance by the photocatalyst, the organic substance is oxidatively decomposed into water and carbon dioxide, so that the foreign substance waste does not remain on the surface of the substrate BS after the removal operation, and the organic foreign substance α is adhered. The periphery of the part is not soiled with rubbish.

Moreover, even if the base material BL of the photocatalytic tape PHT is formed of an organic material, the base material BL is prevented from being decomposed by photooxidation by laminating the photocatalytic layer PHL with the inorganic protective layer PL interposed therebetween. Even the photocatalytic tape PHT using the organic material base BL can be stably used for removing the organic foreign matter α.
Further, the transfer means 500 replaces the portion of the photocatalyst tape PHT used for removing the organic foreign matter α from the used portion for each removal operation to the unused portion, and removes the organic foreign matter α every time the photocatalytic tape PHT is removed. Thus, the removal performance of the organic foreign matter α can be stably maintained.

In this embodiment, the rotating shaft 306 constituting the moving unit 300 is translated in the Z-axis direction, but the moving direction is not limited to the Z-axis direction. For example, the rotating shaft 306 is translated in an arc shape. Thus, the photocatalytic tape PHT can be brought into contact with the organic foreign matter α.
In addition, it is not necessary to move the pair of rotating shafts 306 and 306 at the same time while maintaining a certain relative position, and it is possible to move only the other while the one is fixed.

Further, the photocatalyst is not limited to the photocatalyst tape PHT. For example, a sheet-like photocatalyst coated with a photocatalyst on a sheet-like base material is attached to the frame member, and the frame member is held and pressed against the substrate. can do.
In addition, an elastic sheet-like photocatalyst body is fixed in a state of being attached to the frame member above the substrate, and an opening-shaped cylindrical pressing member surrounding the periphery of the organic foreign matter α is placed inside the cylindrical shape. The sheet-like photocatalyst body is pressed from the side opposite to the substrate BS after being positioned in the XY-axis direction so that the portion corresponding to the cylindrical pressing member of the sheet-like photocatalyst body faces downward. The protruding portion can be brought into contact with the organic foreign matter α on the substrate BS. Here, the light irradiation means (light source) 400 can be installed in the internal space of the cylindrical pressing member.

In the above embodiment, the moving means 300 is configured to move the photocatalyst tape PHT (photocatalyst body) toward the substrate BS. However, the substrate BS can be moved toward the photocatalyst tape PHT (photocatalyst body). .
For example, while the positions of the rotating shafts 306 and 306 shown in FIGS. 1 and 2 are fixed in the Z-axis direction, a lift mechanism (moving means) that lifts the substrate BS toward the photocatalytic tape PHT is provided, and the substrate BS is moved upward. The organic foreign matter α on the substrate BS can be brought into contact with the photocatalyst tape PHT (photocatalyst body) by being moved in parallel.

Further, the photocatalyst tape PHT (photocatalyst) is brought close to the substrate BS, and the substrate BS is brought close to the photocatalyst tape PHT (photocatalyst) to bring the photocatalyst tape PHT (photocatalyst) into contact with the organic foreign matter α on the substrate BS. Can do.
Moreover, the pressure-bonding force when the photocatalyst tape PHT (photocatalyst body) is pressure-bonded to the organic foreign matter α on the substrate BS can be obtained by using the elastic restoring force of an elastic member such as a spring or rubber, and has elasticity, for example. The base member BL side of the photocatalytic tape PHT is pressed toward the substrate BS with a pressing member formed of a material, or the base member BL side of the photocatalytic tape PHT is directed toward the substrate BS with a pressing member supported via an elastic member. By pressing, the photocatalytic layer PHL of the photocatalytic tape PHT can be pressed against the organic foreign substance α on the substrate BS.
Further, the light irradiation means 400 may be configured to irradiate the photocatalyst with light via an optical component such as a mirror, a lens, or an optical fiber.

DESCRIPTION OF SYMBOLS 100 ... Substrate foreign material removal apparatus 200 ... Table 300 ... Moving means 302 ... Pressing slider 306 ... Rotating shaft 400 ... Light irradiation means 500 ... Transfer means 600 ... X-axis slider α ... Organic foreign matter BS ... Substrate PHT ... Photocatalytic tape BL ... Base material PL ... Protective layer PHL ... Photocatalyst layer

Claims (8)

A foreign matter removing device for a substrate that removes foreign matter on a substrate,
A photocatalyst having a substrate coated with a photocatalyst;
Moving means for moving at least one of the photocatalyst body and the substrate in a direction in which the photocatalyst body and the substrate are separated from each other, and bringing the photocatalyst layer of the photocatalyst body into contact with foreign matter on the substrate;
A light irradiation means for irradiating light to the photocatalyst layer in contact with the foreign matter;
An apparatus for removing foreign matter for substrates, comprising: The base material transmits light emitted by the light irradiation means;
2. The foreign substance removing apparatus for a substrate according to claim 1, wherein the light irradiating means irradiates light toward a base material side surface of the photocatalyst body. The photocatalyst is a photocatalytic tape obtained by coating a tape-like substrate with a photocatalyst,
The substrate foreign matter removing apparatus according to claim 1, further comprising a transfer unit configured to transfer the photocatalyst tape through an area where the moving unit contacts the foreign matter.   Each time the transfer means is irradiated by the light irradiation means, the portion of the photocatalyst tape irradiated with light is retracted, and the non-irradiated portion of the photocatalyst tape is brought into contact with foreign matter by the moving means. The substrate foreign matter removing apparatus according to claim 3.   5. The foreign substance removing apparatus for a substrate according to claim 3, wherein the moving means brings the photocatalytic tape stretched between a pair of rotating shafts into contact with the foreign substance on the substrate.   6. The substrate foreign matter removing apparatus according to claim 5, wherein the moving means moves at least one of the pair of rotating shafts in parallel to move the photocatalyst tape in a direction in which the photocatalytic tape is separated from and contacting the substrate.   The tape-shaped substrate of the photocatalytic tape is formed of an organic material, and a protective layer formed of an inorganic material is provided between the tape-shaped substrate and the photocatalytic layer. The substrate foreign matter removing apparatus according to claim 1. A method for removing foreign matter on a substrate,
Contact the photocatalyst layer of the photocatalyst body coated with the photocatalyst on the substrate with the foreign matter on the substrate,
A method for removing foreign matter for a substrate, comprising irradiating the photocatalyst layer in contact with the foreign matter with light.

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