JP4780984B2 - Substrate transfer device - Google Patents

Description

The present invention relates to a substrate transfer apparatus that transfers a large glass substrate, a color filter, and the like used in, for example, a liquid crystal display (LCD) and a plasma display panel (PDP).

In recent years, flat panel displays (FPDs) such as LCDs and PDPs have become widespread, and glass substrates are generally used for these LCDs and PDPs. In order to improve the quality of this glass substrate, it is necessary to inspect defective parts such as scratches and dirt in the manufacturing process.
Therefore, various substrate inspection apparatuses for inspecting these glass substrates are well known (for example, see Patent Document 1).

The substrate inspection apparatus of Patent Document 1 is provided with a roller conveyance unit that carries glass substrates in and out of the upstream and downstream sides of the same surface plate 2 with a defect inspection composed of an air levitation stage. A space for transmitting and illuminating the glass substrate is provided on the air levitation stage on which the substrate is placed for inspection. It is known that an objective lens is provided so as to be movable along the space, and an illumination unit for irradiating illumination light is provided in the space so as to be movable facing the objective lens. Further, the substrate inspection apparatus includes a substrate gripping unit that grips one side of the substrate. The substrate gripping unit in a state of gripping the substrate is moved along the air levitation stage so that the substrate straddles the space. In the meantime, an enlarged image of the substrate surface is obtained by the objective lens and the illumination unit. By observing this magnified image, scratches and defects on the substrate surface are detected.
JP 2000-9661 A

  However, in such a substrate inspection apparatus, since a glass substrate in recent years is larger and thinner in order to meet the demand for a larger screen and a thinner overall device, this substrate is used as an air substrate. When the air is levitated to a certain height by air on the levitation stage, the levitation pressure is lowered between the spaces, and the front end of the substrate in the conveyance direction is bent by its own weight in the space. Therefore, there is a problem that the front end portion is submerged in the space, and as a result, the front end portion is caught and it becomes difficult to smoothly transport the substrate. In particular, when the glass substrate is warped on the back side of the substrate, the tip of the glass substrate is liable to be submerged in the space, the space cannot be overcome, and the glass substrate can be transported stably. become unable.

The present invention was made in view of such circumstances, while maintaining the planar state of the substrate on the space, the substrate transfer apparatus as possible out to be stably conveyed without damage to the substrate The purpose is to provide.

In order to solve the above problems, the present invention provides the following means.
The substrate transfer apparatus of the present invention is arranged with a first levitation stage that blows gas on the back surface of the substrate to support the substrate in a horizontal state, and a predetermined space on the downstream side of the first levitation stage. A space between the second levitation stage, a substrate transport mechanism that holds the substrate and transports the substrate from the first levitation stage to the second levitation stage, and the first levitation stage and the second levitation stage And a roller that prevents the substrate from bending, and the roller is provided so as to be able to appear and retract between the spaces .

In addition, the substrate transfer apparatus of the present invention is arranged with a first levitation stage that blows gas on the back surface of the substrate to support the substrate in a horizontal state, and a predetermined space on the downstream side of the first levitation stage. A second levitation stage, a substrate transport mechanism that holds the substrate and conveys the substrate from the first levitation stage to the second levitation stage, the first levitation stage, and the second levitation stage, A roller for preventing bending of the substrate, and a transmitted illumination for observing the substrate, which is disposed between the space of the first levitation stage and the second levitation stage. The roller is retracted to a position that does not interfere with the transmitted illumination when the substrate is observed.

According to the present invention, it is possible to prevent the substrate from being bent downward by the roller when the substrate passes over the transmission illumination gap provided in the conveying path of the floating stage. Therefore, the planar state of the substrate can be maintained on the transmitted illumination gap , and the substrate can be safely transported on the floating stage .

(Embodiment 1)
Hereinafter, a substrate inspection apparatus which is a substrate transfer apparatus according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a substrate inspection apparatus 1 as an embodiment of the present invention.
The substrate inspection apparatus 1 includes a rectangular base 2 placed on a vibration isolation table (not shown).
Of the upper surface of the base 2, a plurality of sleeper portions 3 extending in a prismatic shape are directed to the depth direction D of the base 2 in the width direction W on one end side (upstream side) 2 a in the width direction W. They are arranged at a predetermined interval. And also on the other end side (downstream side) 2b of the upper surface of the base 2, the plurality of sleepers 3 are directed in the depth direction D of the base 2 in the same manner as described above, and have a predetermined interval in the width direction W. Is placed.

  On the upper surface of the plurality of sleepers 3 arranged on the one end side 2a, a plurality of elongated plate-like first stage constituting members 6 are directed in the width direction W and spaced in the depth direction D (see FIG. 10 are arranged in the example shown. In addition, on the upper surface of the plurality of sleepers 3 arranged on the other end side 2b, a plurality of elongated plate-like second stage constituent members 7 are directed in the width direction W and in the depth direction D, as described above. A plurality (10 in the illustrated example) are arranged at predetermined intervals. A space 15 for transmitted illumination is provided between the upstream air levitation stage constituted by the first stage constituent member 6 and the downstream air levitation stage constituted by the second stage constituent member 7.

  Under such a configuration, a glass substrate (substrate to be inspected) 13 is formed on the top surface (front surface) 6a of the plurality of first stage constituent members 6 and the top surface (surface) 7a of the plurality of second stage constituent members 7. It is supported in a horizontal state and is conveyed in one direction. That is, the plurality of first stage constituent members 6 constitute a first stage (upstream air levitation stage) 10, and the plurality of second stage constituent members 7 constitute a second stage (downstream air levitation stage) 11. The first and second stages 10 and 11 are arranged with a predetermined space 15 along the conveyance path of the glass substrate 13. By arranging these first and second stage constituent members 6 and 7 at a predetermined interval, a linear gap in the direction perpendicular to the transport direction of the glass substrate 13 in this transport path, that is, transmitted illumination. Space 15 is provided.

  In addition, air nozzle holes (floating means) 20 for ejecting air are formed on the top surface 6a of the first stage constituent member 6 and the top surface 7a of the second stage constituent member 7 over the entire length in the length direction, that is, the width direction W. Are formed at equal intervals. These air nozzle holes 20 are connected to an air blowing device (floating means) via the air tanks of the first and second stage constituting members 6 and 7. The compressed air sent from the air blower is supplied to the first and second stage constituent members 6, 7, and blown out from the air nozzle hole 20 in the height direction H of the base 2. It is like that.

Further, a substrate transport mechanism 23 is provided on the top surface of the base 2 to support and transport one side of the glass substrate 13 that has been levitated by air. The substrate transport mechanism 23 includes a prismatic base 24 that is adjacent to the first stage 10 and the second stage 11 and extends in the width direction W over the first and second stages 10 and 11. Yes. A guide rail 25 is disposed on the upper surface of the base 24 over the entire length in the length direction, and a support portion 26 that supports the glass substrate 13 is provided on the guide rail 25. The support portion 26 includes a rectangular base portion 26a extending along the length direction of the top surface of the pedestal 24. The base portion 26a has an upper portion in the height direction H starting from an end portion in the depth direction D. A rising wall portion 26b extending toward the top is provided. A plurality of substrate suction pad members 27 are provided at predetermined intervals on the top surface of the rising wall portion 26b. These substrate suction pad members 27 are connected to an air suction device (not shown) via a tube, and air is sucked from the substrate suction pad member 27 via the tube by driving the air suction device. It is like that.
The support portion 26 reciprocates on the guide rail 25 by, for example, a linear motor.

  With this configuration, when the air suction device is driven to suck air from the substrate suction pad member 27, the edge of the glass substrate 13 on the first stage 10 is sucked by the substrate suction pad member 27, Thus, the glass substrate 13 is cantilevered. Then, by driving the linear motor in this supported state, the support portion 26 moves, and the glass substrate 13 is transported across the space 15 from the first stage 10 to the second stage 11. It is like that.

  A portal-shaped microscope frame 30 is provided in the vicinity of the space 15. The microscope frame 30 is provided in the vicinity of the boundary between the first stage 10 and the second stage 11 and at both ends in the depth direction D, and the height direction H from each of the installation parts 30a. And a horizontal arm portion 30c extending in a depth direction D connecting the upper ends of the side column portions 30b. Of the two installation parts 30a provided at both ends, one installation part 30a is provided in the vicinity of the pedestal 24, and the other installation part 30a is provided at the opposite end. The length of the installation portion 30a in the depth direction D is set to be long, and therefore, the installation portion 30a is provided to protrude outward by a predetermined size in the depth direction D.

Further, the horizontal arm portion 30c is provided with a microscope (observation means) 33 supported by a linear motor or the like so as to be reciprocally movable over the entire length of the horizontal arm portion 30c. The microscope 33 includes a microscope support unit 36 that is attached to the horizontal arm unit 30c so as to be reciprocally movable. The microscope support unit 36 includes a revolver 34 that can replace a plurality of types of objective lenses 35 having different magnifications. The mounted microscope body is attached. The objective lens 35 is disposed above the space 15, and moves along the space 15 when the microscope support 36 is moved.
In addition, on the back side of the first and second stages 10 and 11 facing the objective lens 35, a transmission illumination unit 37 that irradiates illumination light upward in the height direction H is provided. The transmitted illumination unit 37 is configured to be movable together with the objective lens 35 in the space 15. When the transmitted illumination unit 37 moves to the end of the horizontal arm 30c in the direction opposite to the direction in which the objective lens 35 is provided, the transmitted illumination unit 37 moves with the objective lens 35, thereby moving away from the space 15 in the depth direction D. It is arranged at the retreat position K for retreat.

  Further, in the substrate inspection apparatus 1 according to the present embodiment, as shown in FIG. 2, a roller (spacer) 40 that can protrude and retract with respect to the conveyance path surfaces of the first and second stages 10 and 11 is provided in the space 15. ing. A plurality of rollers 40 are provided according to the number of first stage constituent members 6 and second stage constituent members 7 installed. These rollers 40 are disposed between the first stage constituent member 6 and the second stage constituent member 7 when the end portion of the glass substrate 13 conveyed from the first stage constituent member 6 side gets over the space 15. It appears and fills the opening of the space 15. The roller 40 is made of a resin such as a peak resin (polyetheretherketone) that is softer than glass and has wear resistance. Furthermore, both ends of these rollers 40 are attached to the tip end portion of a substantially L-shaped L-shaped support member 41 via a pin (not shown), whereby the roller 40 is centered on an axis along the depth direction D. Is supported as rotatable.

  As shown in FIG. 3, a single rotating rod 43 extending in the depth direction D is inserted through the base end portions of the plurality of L-shaped support members 41, as shown in FIG. 3. Thereby, the L-shaped support member 41 is supported. Further, the rotating rod 43 is rotatably supported by a bearing 42, and the bearing 42 is attached to each of the back surfaces 6 b of the plurality of first stage constituent members 6. A rotation drive unit 44 such as a double-axis motor that rotates the rotating rod 43 in both forward and reverse directions is provided at the center of the rotating rod 43 in the length direction.

  Under such a configuration, by rotating the rotation rod 43 by driving the rotation drive unit 44, the roller 40 is disposed in the space 15 to fill the space 15, and the closed position L shown in FIG. As shown in FIG. 4, the reciprocation is made between the open position M where the space 15 is opened by retreating from the space 15.

Next, the operation of the substrate inspection apparatus 1 in the present embodiment configured as described above will be described.
In the initial state, the support section 26 is disposed on the first stage 10 side, the transmitted illumination section 37 is disposed at the retracted position K, and the microscope 33 is disposed at the end of the horizontal arm section 30c on the retracted position K side. Furthermore, it is assumed that the roller 40 is disposed at the closed position L.
First, the glass substrate 13 is placed on the top surface 6a of the first stage 10 by a transfer device (not shown). When the air blower is driven in this state, air is sent to the air nozzle holes 20 and the air is ejected upward from the air nozzle holes 20. The glass substrate 13 is pressed upward by this air, whereby the glass substrate 13 rises to a certain height from the top surface 6a and is in a non-contact state with the top surface 6a. When the air suction device is driven from this state, air is sucked from the substrate suction pad member 27 and the edge of the glass substrate 13 is sucked to the substrate suction pad member 27. Thereby, the glass substrate 13 is cantilevered. At this time, since air is ejected from the air nozzle hole 20, the air layer between the stage surface and the glass substrate 13 prevents the glass substrate 13 from floating horizontally and coming into contact with the top surface 6a. The

As described above, when the linear motor is driven in a state where the glass substrate 13 is supported by the support portion 26, the support portion 26 moves on the guide rail 25 from the first stage 10 to the second stage 11. Therefore, the glass substrate 13 is transported across the space 15 from the first stage 10 to the second stage 11.
Here, when the front end portion 13a in the moving direction of the glass substrate 13 reaches the space 15 from the first stage 10 in the middle of the conveyance, the front end portion 13a of the glass substrate 13 bends in the conventional case. However, in this embodiment, bending of the end of the glass substrate 13 is prevented as follows.

  That is, when the front end portion 13 a of the glass substrate 13 gets over the space 15, when the roller 40 appears from within the space 15 and closes the opening of the space 15, the front end portion 13 a of the glass substrate 13 is placed on the outer peripheral surface of each roller 40. It contacts and the bending of the glass substrate 13 is prevented. Then, the glass substrate 13 is sent to the second stage 11 while the tip portion 13 a is in contact with the outer peripheral surface of the roller 40, that is, while the roller 40 rotates, following the movement of the support portion 26. The glass substrate 13 sent to the second stage 11 is pressed upward by the air ejected from the air nozzle hole 20 and floated to a certain height. When the distal end portion 13a of the glass substrate 13 gets over the space 15 and reaches the second stage 11, the rotation driving unit 44 is driven. The rotation driving unit 44 rotates the L-shaped support member 41 attached to the rotating rod 43, and the roller 40 is retracted from the opening of the space 15 to the open position M. As a result, the space 15 is released. At this time, as described above, the tip portion 13a is pushed upward by the air of the second stage 11 and floats, so that the glass substrate 13 bends between the spaces 15 even if the spaces 15 are opened. Without being floated and held in a horizontal state.

  In this state, the microscope 33 and the transmitted illumination unit 37 are moved in synchronization. At this time, since the roller 40 is disposed at the open position M, the transmitted illumination unit 37 moves in the space 15. The transmitted illumination unit 37 irradiates illumination light upward in the space 15, and the illumination light passes through the glass substrate 13 and is taken into the microscope 33 through the objective lens 35. Thereby, an enlarged image of the glass substrate 13 is obtained. In this way, by observing the magnified image of the glass substrate 13 while transporting the glass substrate 13 at a desired timing, the surface of the glass substrate 13 is inspected, and defective portions such as scratches and dirt are detected. . Then, when the inspection is finished, the glass substrate 13 is unloaded from the second stage 11 by an unillustrated unloader.

  Then, the support unit 26 is returned to the first stage 10 side, the transmitted illumination unit 37 is moved and disposed at the retracted position K, and then the rotation driving unit 44 is driven again to rotate the rotating rod 43 in the forward direction. Let Then, the roller 40 is arranged at the closed position L and returns to the initial state. Then, a new glass substrate 13 is conveyed and the above series of inspections are repeated.

As mentioned above, according to the board | substrate inspection apparatus 1 in this embodiment, by moving the roller 40 between the closed position L and the open position M, the movement by the transmission illumination part 37 is enabled in the space 15, and roller 40 can fill the space 15. Therefore, when the glass substrate 13 gets over the space 15, the space on the space 15 is closed by the roller 40, so that the tip end portion 13 a of the glass substrate 13 is in contact with the roller 40 and is not bent downward. Thus, the glass substrate 13 can be safely transported to the second stage 11.
Further, since the spacer is the roller 40, it is possible to prevent the back surface of the glass substrate 13 from being rubbed and damaged during the conveyance of the glass substrate 13.
Further, since the roller 40 is made of a peak resin, it is possible to prevent the back surface of the glass substrate 13 from being damaged during the conveyance, and to improve the durability of the roller 40.

  In the present embodiment, the L-shaped support member 41 has an L-shape. However, the present invention is not limited to this. For example, the L-shaped support member 41 extends from the rotary rod 43 into the space 15 and rotates. Any shape that does not hinder the rotation of the rod 43 can be changed as appropriate.

(Embodiment 2)
Next, a second embodiment of the present invention will be described.
5 to 8 show a second embodiment of the present invention.
5 to 8, the same components as those shown in FIGS. 1 to 4 are denoted by the same reference numerals, and the description thereof is omitted.
This embodiment and the first embodiment have the same basic configuration, and are different in the following points.

That is, in this embodiment, as shown in FIGS. 5 and 6, the L-shaped support member (spacer support member) 41 has a predetermined interval between a single mounting plate 50 extending in the depth direction D. The mounting plate 50 is connected to an intermediate member 47 extending in the depth direction D. Further, the intermediate member 47 is connected to a base member 48 that is oriented in the depth direction D and extends in a prismatic shape.
The base member 48 is attached to the sleeper portion 3 provided on the back surface 7 b of the second stage 11 via the connecting plate 51. Base engaged portions 49 are provided at both ends of the base member 48 in the length direction.

  Further, the intermediate member 47 is formed in an L shape in cross section, and has a base plate part 47a extending in the depth direction D and extending along the back surface 7b, and a height direction H in the depth direction D. The orthogonal plate part 47b extending along the line is integrally connected. A base engaging portion 53 is provided at both ends of the back surface of the base plate portion 47a in the length direction. The base engaging portion 53 engages with the base engaged portion 49, whereby the intermediate member 47 is provided. Is supported so as to be capable of reciprocating in the arrangement direction of the first stage 10 and the second stage 11, that is, in the width direction W. The base plate portion 47 a is connected to a horizontal air cylinder 58 attached to the base member 48, and is reciprocated in the width direction W by the horizontal air cylinder 58. In addition, orthogonal engaged portions 54 are provided at both ends in the length direction of the surface disposed on the first stage 10 side in the outer surface of the orthogonal plate portion 47b.

  Furthermore, attachment engagement portions 56 are provided at both ends in the length direction of the attachment plate 50, and these attachment engagement portions 56 engage with the orthogonally engaged portions 54, respectively. Is supported so as to be reciprocally movable in a direction orthogonal to the direction in which the top surface 7a extends, that is, in the height direction H. The attachment plate 50 is connected to a vertical air cylinder 59 attached to the orthogonal plate portion 47b, and is reciprocated in the height direction H by the vertical air cylinder 59.

Under such a configuration, when air is supplied to the horizontal air cylinder 58, the intermediate member 47 moves to the first stage 10 side and air is supplied to the vertical air cylinder 59 as shown in FIG. The plate 50 moves upward. Accordingly, the roller 40 appears at the opening of the space 15 and is disposed at the closed position L that closes the opening of the space 15.
On the other hand, when air is sucked from the vertical air cylinder 59, as shown in FIG. 8, the roller 40 is moved downward via the mounting plate 50. From this state, when air is sucked from the horizontal air cylinder 58, the intermediate member 47 is moved. Moves in the opposite direction, and the roller 40 is retracted to the open position M that does not interfere with the transmitted illumination by sinking from the opening of the space 15.

  As described above, not only can the same effect as in the first embodiment be obtained, but also the roller 40 can be reliably moved between the closed position L and the open position M.

(Embodiment 3)
Next, a third embodiment of the present invention will be described.
9 and 10 show a third embodiment of the present invention.
This embodiment and the second embodiment have the same basic configuration, and are different in the following points.

That is, in this embodiment, the intermediate member 47 is rotated 90 degrees clockwise with respect to the paper surface of FIG. 7, and the direction of the intermediate member 47 is changed. However, various changes have been made with changes in the orientation, as will be described later. Moreover, the sleeper part 3 functions also as the base member 48 in the said 2nd Embodiment, and both are combined.
At both ends of the sleeper portion 3 in the length direction, base engaged portions 49 directed in the height direction H are provided.
The base plate portion 47a is erected in the height direction H, and base engaging portions 53 are provided at both ends in the length direction. The base member engaging portion 53 engages with the base engaged portion 49, whereby the intermediate member 47 is supported so as to be reciprocally movable in the height direction H.

Furthermore, orthogonal engaged portions 54 directed in the width direction W are provided at both ends in the length direction of the upper surface of the orthogonal plate portion 47b.
Further, the mounting plate 50 is laid down along the back surface 7b, and mounting engaging portions 56 are provided at both ends in the length direction. The attachment plate 50 is supported so as to be able to reciprocate in the width direction W by the attachment engagement portions 56 engaging with the orthogonal engaged portions 54. The rear surface of the base end portion of the L-shaped support member 41 is attached to the top surface of the mounting plate 50.

In order to close the space 15 under such a configuration, the L-shaped support member 41 is moved to the first stage via the mounting plate 50 as shown in FIG. 10 side, and the intermediate member 47 is moved upward. Accordingly, the roller 40 appears at the opening of the space 15 and is disposed at the closed position L that closes the opening of the space 15.
On the other hand, in order to open the space 15, as shown in FIG. 10, first, the intermediate member 47 is moved downward, and then the L-shaped support member 41 is moved in the opposite direction via the mounting plate 50. As a result, the roller 40 is retracted to the open position M that does not obstruct the transmitted illumination by sinking from the opening of the space 15.

  From the above, not only can the same effect as the second embodiment be achieved, but also the cost can be reduced by reducing the number of parts.

In the second and third embodiments, the shapes and orientations of the L-shaped support member 41, the intermediate member 47, and the base member 48 can be changed as appropriate.
In the first to third embodiments, a plurality of rollers 40 are provided according to the number of first stage constituent members 6 and second stage constituent members 7, but the present invention is not limited to this. The number of installations and length dimensions can be changed as appropriate. For example, the roller 40 may be thinned out. Moreover, you may make it provide the one roller 40 extended over the both ends of the depth direction D of the 1st and 2nd stage 10 and 11. FIG.
Further, the roller 40 may be fixed instead of rotating. However, it is preferable to rotate the roller 40 as described above from the viewpoint of preventing damage to the glass substrate 13 as described above.

Moreover, although the glass substrate 13 was floated by ejecting air, it is not restricted to this, It can change suitably. For example, you may make it float using static electricity etc.
Furthermore, although the glass substrate 13 is supported in a cantilever manner, the present invention is not limited to this, and the support portions 26 are provided on both sides of the first and second stages 10 and 11 so as to support the glass substrate 13 in both ends. May be.
In addition, although an enlarged image is obtained by the microscope 33, the present invention is not limited to this, and the inspection may be performed by scanning the CCD camera or the like along the space 15 and processing the image data. .
The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

It is a perspective view which shows 1st Embodiment of the board | substrate conveyance apparatus which concerns on this invention. It is a perspective view which shows a mode that the principal part of the space periphery shown in FIG. 1 was expanded and it looked from upper direction. It is a perspective view which shows a mode that the principal part around the space of FIG. 2 was seen from the downward direction. It is a perspective view which expands and shows a mode when a roller is distribute | arranged to the open position. It is a figure which shows the principal part of 2nd Embodiment of the board | substrate conveying apparatus which concerns on this invention, Comprising: It is a perspective view which shows a mode that it saw from upper direction. Is a perspective view showing a state viewed board conveying device of FIG. 5 from below. It is explanatory drawing which shows a mode that the roller of FIG. 5 moves to a height direction. It is explanatory drawing which shows a mode that the roller of FIG. 5 moves to the width direction. It is a figure which shows the principal part of 3rd Embodiment of the board | substrate conveying apparatus which concerns on this invention, Comprising: It is explanatory drawing which shows a mode that a roller moves to the width direction. In the same embodiment, it is explanatory drawing which shows a mode that a roller moves to a height direction.

Explanation of symbols

1 Board inspection device 6a Top surface (surface)
6b Back surface 7a Top surface (front surface)
7b Back surface 10 First stage 11 Second stage 13 Glass substrate (substrate)
15 Space 20 Air nozzle hole (Floating means)
23 substrate transport mechanism 26 support part 33 microscope (observation means)
37 Transmitted illumination unit 40 Roller (spacer)
41 L-shaped support member (spacer support member)
42 Bearing 43 Rotating rod 47 Intermediate member 48 Base member 50 Mounting plate 51 Connecting plate L Closed position M Open position

Claims (3)

A first levitation stage that blows gas on the back surface of the substrate to support the substrate in a horizontal state;
A second levitation stage disposed with a predetermined space downstream of the first levitation stage;
A substrate transport mechanism for holding the substrate and transporting the substrate from the first levitation stage to the second levitation stage;
A roller provided between a space between the first levitation stage and the second levitation stage to prevent bending of the substrate;
Equipped with a,
The substrate transporting apparatus according to claim 1, wherein the roller is provided so as to be able to appear and retract between the spaces . A first levitation stage that blows gas on the back surface of the substrate to support the substrate in a horizontal state;
A second levitation stage disposed with a predetermined space downstream of the first levitation stage;
A substrate transport mechanism for holding the substrate and transporting the substrate from the first levitation stage to the second levitation stage;
A roller provided between a space between the first levitation stage and the second levitation stage to prevent bending of the substrate;
A transmitted illumination for observing the substrate, disposed between the space of the first levitation stage and the second levitation stage ;
Equipped with a,
The substrate transfer apparatus , wherein the roller is retracted to a position that does not interfere with the transmitted illumination when the substrate is observed . 3. The substrate transport apparatus according to claim 1, wherein the roller appears so as to fill at least a part of the space when the substrate is transported across the space.

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