JP2009161283A - Levitating unit and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a levitating unit and a device capable of levitating and conveying a workpiece such as a glass substrate while suppressing any warp generated in the workpiece. <P>SOLUTION: The levitating unit has a chamber 36. A vent hole communicated with an airtight space in the chamber is formed in a ceiling wall of the chamber 36. The levitating unit alternately has a perforated plate 76 and a nonporous plate 77 forming a conveying passage surface F with their lower sides being fixed to the ceiling wall along the workpiece conveying direction U. The levitating unit supplies gas into the airtight space and jets the gas from the conveying passage side through a space between the vent hole and the perforated plate 76. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a levitation unit and an apparatus that levitates a workpiece such as a liquid crystal display (LCD), a plasma display panel (PDP), and a color filter and conveys the workpiece without contact.

  Glass substrates used in flat panel displays (FPD) such as LCDs and PDPs tend to increase in size in response to demands for larger screens.

  In a conventional FPD manufacturing process, a glass substrate is transported by a roller. However, due to friction between the glass substrate and the roller, a problem of stress applied to the glass substrate, etc., the glass substrate is floated by compressed air and transported. Is considered.

However, as shown in FIG. 15, the levitation unit as in Patent Document 1 employs a method in which air is blown up from the air blowing holes 204 formed in the ceiling wall 202 of the levitation block 200 to float the glass substrate 206. Therefore, the glass substrate 206 is warped between the air blowing holes 204.
JP 2004-331265 A

  This invention considers the fact which concerns, and makes it a subject to provide the levitation unit and apparatus which can be floated and conveyed, suppressing the curvature which generate | occur | produces workpiece | works, such as a glass substrate.

  According to the first aspect of the present invention, an airtight space is formed, a fluid passage hole communicating with the airtight space is formed in the ceiling wall, a lower side is fixed to the ceiling wall, and a workpiece is provided on the upper side. A porous body that forms a transport path for transporting, and a non-porous body that has a lower side fixed to the ceiling wall and a transport path for transporting a workpiece on the upper side. The porous body and the non-porous body are disposed so that the body is discontinuously disposed in the workpiece conveyance direction.

In the first aspect of the present invention, when a fluid is supplied to the airtight space of the chamber by a fluid supply means such as a compressor, the fluid is ejected from a fluid passage hole formed in the ceiling wall. Since the porous body is fixed to the ceiling wall, the fluid is ejected from the gap of the porous body.
That is, on the upper side of the porous body, that is, on the conveyance path side, the fluid is ejected from the entire surface and the entire surface becomes the air bearing surface, so that it is possible to float and convey while suppressing warpage generated on the workpiece.

Further, the non-porous body and the porous body that form the transport path on the upper side are disposed so as to be discontinuously disposed in the work transport direction. For this reason, the fluid ejected from the fluid passage hole formed in the ceiling wall passes through only the porous body without passing through the non-porous body, and is ejected to the conveyance path side.
Therefore, the number of porous bodies arranged can be reduced, and the equipment cost can be greatly reduced. In addition, it is possible to prevent the flow rate of the fluid ejected to the conveyance path side from being too large and the conveyance state from becoming unstable and the running cost from increasing.

  In addition, when the dimensions and weight of the workpiece to be conveyed are known in advance, a non-porous body is formed according to the size and weight of the workpiece so that the workpiece is given a proper buoyancy distribution and no warpage occurs. It is preferable that the length in the workpiece conveyance direction is set.

The invention described in claim 2 is characterized in that the porous body and the non-porous body are alternately arranged in a workpiece transfer direction.
According to the second aspect of the present invention, the size of the region where the fluid is not ejected in the transport path can be minimized. Therefore, the fluid can be efficiently ejected when the workpiece is floated and conveyed.

The invention described in claim 3 is characterized in that the porous body and the non-porous body are detachable from the ceiling wall.
In the invention described in claim 3, the number and arrangement of the porous body and the non-porous body can be flexibly changed according to the size and weight of the workpiece to be levitated and conveyed.

According to a fourth aspect of the present invention, a plurality of the conveyance paths are formed by providing a plurality of the chambers in parallel along the workpiece conveyance direction. The porous body is arranged so as to be adjacent to the workpiece conveyance direction.
In the invention according to claim 4, when a plurality of transport paths are formed, the size of the region where the fluid is not ejected can be minimized. Therefore, the fluid can be efficiently ejected when the workpiece is floated and conveyed.

  The invention according to claim 5 is characterized in that a protective film is formed on the conveyance path side of the porous body.

The method for forming the protective film is not particularly limited. For example, known methods such as painting, electrolytic plating, electroless plating, physical vapor deposition (PVD, vacuum deposition, ion plating, sputtering, etc.), chemical vapor deposition (CVD), ion plantation, etc. By doing so, a protective film is formed.
In the invention described in claim 5, prevention of peeling of the porous body and improvement of strength are achieved by the protective film formed on the upper side of the porous body.

The invention described in claim 6 is characterized by having the levitation unit described in any one of claims 1 to 5.
Examples of the apparatus include an exposure apparatus, an inspection apparatus, a defect repair apparatus, and a coater apparatus.

  The invention described in claim 7 has a porous body forming a workpiece conveyance path on the upper side, and an airtight space communicating with the conveyance path side through the porous body below the porous body. A non-porous body is disposed so that the chamber is formed, and the chamber is discontinuously disposed in the workpiece transfer direction.

According to the seventh aspect of the present invention, when a fluid is supplied to the airtight space of the chamber by a fluid supply means such as a compressor, the fluid is ejected from the gap of the porous body.
That is, on the upper side of the porous body, that is, on the conveyance path side, the fluid is ejected from the entire surface and the entire surface becomes the air bearing surface, so that it is possible to float and convey while suppressing warpage generated on the workpiece.
Thus, the same actions and effects as those of the first aspect of the invention can be achieved.

According to an eighth aspect of the present invention, the chamber is provided with a ceiling wall that forms a ceiling side of the hermetic space and is formed with a fluid passage hole communicating with the hermetic space, and the porous body is provided on the ceiling. It is arranged on the upper side of the wall.
In the seventh aspect of the invention, the fluid is ejected from the airtight space through the fluid passage hole, and further, the fluid is ejected from the void of the porous body.

  Since this invention set it as the said structure, the curvature which generate | occur | produces workpiece | works, such as a glass substrate, can be suppressed and it can be made to convey.

[First Embodiment]
1 to 3 show an exposure apparatus 12 in which the floating unit according to the first embodiment is incorporated.

(Basic configuration)
The exposure apparatus 12 includes an assembly frame 18 configured in a long frame shape with rails 14 and cross members 16. The assembly frame 18 is supported above the frame-like base frame 22 by the post 20.

  A plurality of beam members 28 are bridged between the rails 14. An air supply box 29 to which negative pressure and positive pressure air is supplied from the first compressor 32 via the tube 34 is disposed on the beam member 28 on one end side of the chamber 36. On the air supply box 29, three rows of the floating units 10 according to the first embodiment are set along the rails 14. Note that what is supplied from the compressor is not limited to air, but may be an inert gas such as nitrogen, argon, or helium, or a gas such as carbon dioxide. Moreover, liquids, such as water, may be sufficient.

  The air supply box 29 may be an ejector that generates a negative pressure and a positive pressure with the pressurized air supplied from the first compressor 32. Instead of the air supply box 29, a height adjusting member 30 may be disposed.

  Further, a height adjusting member 30 for adjusting the height of the chamber 36 is disposed on the beam member 28 on which the air supply box 29 is not disposed. Instead of the air supply box 29, a height adjusting member 30 may be disposed.

  The bottom plate of the chamber 36 of the levitation unit 10 is formed with three supply ports (not shown) connected to the air supply box 29 and supplied with negative and positive pressure air.

  Further, a support plate 38 is bridged between the rails 14 on the right side of the rails 14 shown in FIG. A floating unit 40 according to a second embodiment to be described later is set on the support plate 38. From the lower surface side of the support plate 38, negative pressure and positive pressure air are supplied from the second compressor 44 through the tube 46. Then, negative pressure and positive pressure air are supplied to three supply ports (not shown) formed in the bottom plate of the chamber 80 of the levitation unit 40.

  Further, a linear transport device 50 is mounted on the rail 14 on the near side. The transfer device 50 includes a plurality of vacuum suction cups 52 and is configured to chuck the lower surface of the floated glass substrate P and transfer it in the workpiece transfer direction U. The transfer device 50 can also move in the direction opposite to the workpiece transfer direction U.

  The glass substrate P levitated above the levitation unit 10 is levitated and conveyed toward the levitation unit 40 by the conveying device 50. The glass substrate P that has been levitated and conveyed is exposed by an exposure unit (not shown) while the levitated state is maintained above the levitating unit 40, and a predetermined circuit pattern is formed.

  The chamber 36 is formed with a flow path (not shown) through which a cooling medium (for example, water) flows along the longitudinal direction. This flow path is directed downward at a position slightly downstream of the adjustment member 30 disposed on the upstream side of the workpiece conveyance of the levitation unit 10 in the conveyance direction, and a water supply port is formed at the lower end of the water supply pipe. 55 (see FIG. 1) is connected. Further, this flow path is directed downward at a position slightly upstream of the air supply box 29 disposed on the downstream side of the work transfer of the levitation unit 10, and a drain outlet is formed at the lower end. A drain pipe 57 (see FIG. 1) is connected. Thereby, the cooling effect is greater on the upstream side of the flow path in the workpiece conveyance direction than on the downstream side of the workpiece conveyance direction.

(Specific configuration)
Next, a specific configuration of the levitation unit 10 according to the first embodiment will be described.

  As shown in FIGS. 4 to 9, the chamber 36 of the levitation unit 10 is a long cylindrical body having a rectangular cross section, and the inner space is formed by two partition walls 54 provided on the inner side and has a rectangular cross section at the center. It is divided into a suction chamber 56 and ejection chambers 58 and 60 having a rectangular cross section. Then, by joining the side plate 62 to the end face of the chamber 36, the suction chamber 56 and the ejection chambers 58, 60 of the chamber 36 become an airtight space.

  As shown in FIG. 6, a pedestal portion 152 in which a screw hole 150 is formed is provided on the end surface of the chamber 36. Further, a mounting hole 154 is formed in the side plate 62. The screw hole 150 and the attachment hole 154 are formed in a positional relationship where the screw hole 150 and the attachment hole 154 face each other when the side plate 62 is overlapped on the end face of the chamber 36. Then, the screw 36 is inserted into the mounting hole 154 and the screw hole 150 with the screw hole 150 and the mounting hole 154 facing each other, whereby the chamber 36 and the side plate 62 are screwed together.

  The chamber 36 and the side plate 62 can be joined by other means such as an adhesive in addition to screwing with the screw 156.

  However, when the chamber 36 and the side plate 62 are joined together by an adhesive, the curing time of the adhesive is required, so that the production efficiency cannot be improved, and it is difficult to disassemble after joining. Therefore, it is difficult to perform maintenance or replacement of parts. Therefore, it is preferable to join the chamber 36 and the side plate 62 with the screw 156 as described above.

  Negative pressure air is supplied to the suction chamber 56 from the aforementioned supply port, and positive pressure air is supplied to the ejection chambers 58 and 60.

  A long groove 64 is formed on the side surface of the chamber 36 along the longitudinal direction in order to reduce the weight.

  On the other hand, a lattice groove portion (lattice-like groove portion) 68 divided into four sections is formed on the ceiling wall 37 of the chamber 36. The reason why the lattice groove portions 68 are formed in each of the sections is that air can be uniformly supplied to the porous plate 76 joined to the ceiling wall 37. However, in the present invention, the number of compartments in which the lattice groove 68 is formed is not limited, and the chamber 36 may be configured by one compartment.

  A plurality of ventilation holes 74 that are fluid passage holes of the present invention pass through the groove bottom of the lattice groove portion 68 and are arranged in a straight line. The ventilation hole 74 communicates with the ejection chamber 60. An air intake hole 70 is formed in the groove bottom of the lattice groove portion 68 and communicates with the suction chamber 56. And the ventilation hole 72 which is the fluid passage hole of this invention is formed in the groove bottom of the lattice groove part 68. FIG. The vent hole 72 communicates with the ejection chamber 58.

A porous plate 76 or a non-porous plate 77 processed into a plate shape is joined to the ceiling wall 37 of the chamber 36 in which the groove portion is formed in this way.
The porous plate 76 can be made of, for example, porous graphite, sintered metal, porous ceramics, porous resin, or the like.

  When composed of porous graphite, it is possible to improve the weight reduction, the mechanical strength, the manufacturing cost, the surface flatness, and when the glass substrate P comes into contact with the glass substrate P, Damage can be reduced. In addition, the weight of the porous plate can be reduced. In addition, the function of electrostatic grounding due to the conductivity of the porous plate 76 can be added.

When the air permeability of the porous plate 76 is in the range of 0.2 to 6.0 cm ² / s, the work (glass substrate P) conveyed by the levitation unit 10 can be effectively levitated. Moreover, a workpiece | work can be levitated more effectively as the porosity of the porous board 76 is 5-25 vol%.

  In the present embodiment, every other porous plate 76 is arranged. That is, in each chamber 36, the porous plate 76 and the non-porous plate 77 are joined to the ceiling wall 37 alternately along the workpiece conveyance direction U.

The upper surface side of the non-porous plate 77 constitutes a conveyance path surface F that conveys the workpiece. Therefore, the conveyance path surface F is formed by the upper surface of the porous plate 76 that ejects air and the upper surface of the non-porous plate 77 that does not eject air. In the present embodiment, the porous plate 76 and the non-porous plate 77 have the same dimensions, and the upper surface of the porous plate 76 and the upper surface of the non-porous plate 77 are located on the same plane.
The ceiling wall located below the non-porous plate 77 may not be formed with the lattice grooves 68, the air intake holes 70, and the air holes 72, 74. The ceiling wall structure can be simplified.

  The material of the non-porous plate 77 is not particularly limited as long as it can be attached to the chamber 36 and does not eject air. A metal plate such as a stainless steel plate or a resin plate may be used. Further, it may be a plate made of carbon such as graphite, or may be a ceramic plate in order to be heat resistant and non-metallic.

  In a state where the chamber 36 and the porous plate 76 are joined, the suction hole 70 formed in the chamber 36 and the suction hole 78 formed in the porous plate 76 communicate with each other so as to face each other.

  As a joining method, the surface to be the air bearing surface of the porous plate 76 is placed on the surface plate, the adhesive is applied to the ceiling wall 37 of the chamber 36, and the weight is placed on the porous plate 76. An example is the method of fixing the The adhesive is preferably applied so as not to protrude into the lattice groove 68.

  Here, the lattice grooves 68 are not formed on the back surface of the porous plate 76 but formed on the ceiling wall 37 of the chamber 36, compared to the case where the groove portions are formed on the back surface of the porous plate 76. This is because the groove portion can be easily formed with high accuracy when the groove portion is formed on the ceiling portion.

  Here, a mechanism in which air is ejected from the gap of the porous plate 76 to make the entire surface an air bearing surface will be briefly described.

  In the porous plate 76, a plurality of fine voids communicating with each other are formed. The air ejected from the lattice groove portion 68 passes through the air gap formed by the lattice groove portion 68 and the lower surface of the porous plate 76 and passes through the gap of the porous plate 76, and from the bearing surface of the porous plate 76 to the outside. It spouts towards. At this time, since the minute gaps communicate with each other, the fine gaps are ejected not only from above the air passage but also from the entire bearing surface.

  Next, the operation of the levitation unit 10 according to the first embodiment will be described.

  From the first compressor 32, positive pressure air (for example, 50 to 400 kPa) is supplied to the ejection chambers 58 and 60, and negative pressure air (for example, 0 to −50 kPa) is supplied to the suction chamber 56 (air is supplied from the suction chamber 56). Suction.

  The air supplied to the ejection chambers 58, 60 is ejected from the vent holes 72, 74, travels through the air passage formed by the lower surface of the porous plate 76 and the lattice grooves 68, and is evenly applied to the lower surface of the porous plate 76. And then ejected from the gap of the porous plate 76.

  That is, since air is ejected from the entire surface of the porous plate 76 and the entire surface of the porous plate 76 becomes an air bearing surface, the glass substrate P is levitated without causing warpage, and the porous plate 76 and the non-porous surface are formed. It becomes possible to convey the material plate 77 in a non-contact manner. The sucker 52 chucks the floated glass substrate P, and the conveying device 50 conveys it in the workpiece conveying direction U (see FIG. 1).

  The negative pressure air supplied to the suction chamber 56 generates a force for sucking the glass substrate P into the suction hole 78 formed in the porous plate 76 through the suction hole 70. The suction force generated by the intake holes 70 regulates the flying height of the glass substrate P that has been floated by the air ejected from the porous plate 76. Therefore, the flying height of the glass substrate P can be controlled by controlling the suction force.

  Moreover, when the glass substrate P moves in the workpiece conveyance direction U, a part of the air below the glass substrate (hereinafter referred to as workpiece lower air L (see FIG. 8)) is conveyed along with the glass substrate P by the viscosity of the air. Move to. The movement of the work lower air L from the porous plate 76 onto the nonporous plate 77 contributes to imparting buoyancy to the glass substrate P on the nonporous plate 77.

  Further, the porous plate 76 and the non-porous plate 77 are alternately arranged in the workpiece conveyance direction U, and the porous plate 76 and the non-porous plate 77 are discontinuously arranged in the workpiece conveyance direction U. Accordingly, the number of the porous plates 76 arranged can be reduced, and the equipment cost and running cost can be greatly reduced.

  In addition, the air ejected from the vent holes 72 and 74 formed in the ceiling wall 37 passes through only the porous plate 76 without passing through the non-porous plate 77 and is ejected to the conveyance path surface F side. Therefore, it is prevented that the flow rate of the air jetted to the conveyance path surface F side is too large and the conveyance state becomes unstable and the running cost increases.

  In addition, since the porous plates 76 and the non-porous plates 77 are alternately arranged in the workpiece transfer direction U, the size of the region where air is not ejected on the transfer path surface F can be minimized. Accordingly, air can be efficiently ejected when the work is lifted and conveyed.

  The porous plate 76 and the non-porous plate 77 may be detachable from the ceiling wall 37. Thereby, the number and arrangement of the porous plates 76 and non-porous plates 77 can be flexibly changed according to the size and weight of the workpiece to be floated and conveyed.

[Second Embodiment]
Next, the levitation unit 40 according to the second embodiment will be described.

  Since the basic configuration of the levitation unit 40 is the same as that of the levitation unit 10 of the first embodiment, the configuration of the groove portion of the chamber 80 shown in FIGS. 10 and 11 and the configuration and shape of the porous plate 82 will be described. .

  On the ceiling wall of the chamber 80, four vertical groove portions 97 in the longitudinal direction and a plurality of horizontal groove portions 102 are formed in the width direction, and a plurality of islands 86 are formed at predetermined intervals by the vertical groove portions 97 and the horizontal groove portions 102. Has been. A vent hole 92 is formed in the groove bottom of the lateral groove portion 102. The vent hole 92 communicates with an ejection chamber (not shown). The remote island 86 has an intake hole 90 communicating with the suction chamber.

  On the other hand, a suction hole 96 is formed in the porous plate 82 at a position corresponding to the suction hole 90 when it is overlapped with the ceiling wall of the chamber 80. Further, through holes 101 are formed on both sides of the porous plate 82, and the porous plate 82 can be fixed to the chamber 80 by inserting screws into the mounting holes 94 formed in the chamber 80. Yes.

  In the floating unit 40 having the above-described configuration, the through holes 101 are formed on the surface of the porous plate 82 to enable screwing. Further, since the groove is not formed in the porous plate 82, the flatness of the porous plate 82 can be maintained. Furthermore, by arranging the intake holes at equal intervals, the flying height of the glass substrate P can be regulated in a well-balanced manner. The porous plate 82 may be bonded to the chamber 80 with an adhesive.

In the embodiment shown in FIGS. 1 to 9, the floating unit 10 is configured by joining two porous plates 76 and two nonporous plates 77 to the ceiling wall 37 of the chamber 36. In the embodiment shown in FIGS. 10 and 11, the levitation unit 40 has a single porous plate 82 joined to the ceiling wall of the chamber 80. However, in the present invention, the number of porous plates is not limited. For example, in the embodiment shown in FIGS. 1 to 9, one porous plate 76 and one non-porous plate 77 are joined to the ceiling wall 37 of the chamber 36 along the workpiece conveyance direction U. May be. This case is also included in the “discontinuous arrangement” in the present invention. Moreover, not only a porous board but a general porous body may be sufficient as long as a conveyance path can be formed in the upper surface side.
In addition, a structure in which only the porous plate is bonded to the ceiling wall of the chamber 36 and a structure in which only the non-porous plate is bonded are arranged discontinuously along the workpiece transfer direction U. Also good. In this case, the case where one by one is arranged next to each other is also included in the “discontinuous arrangement” in the present invention.

[Third Embodiment]
Next, a third embodiment will be described. As shown in FIG. 12, in the levitation unit according to the present embodiment, a porous plate 116 in which a protective film 114 is formed on the conveyance path surface side is provided instead of the porous plate 76 as compared with the first embodiment. ing.

  The upper surface side of the porous plate 116 is covered with a protective film 114 (see FIG. 6) in order to prevent peeling of the porous plate 116 and improve strength. Suitable for use in a clean room because particle generation due to peeling can be suppressed. The protective film 114 is formed so as not to block a gap opened on the upper surface of the porous plate 116. A transport path F is formed by the porous plate 116 and the protective film 114.

  The protective film 114 is made of, for example, a resin. Thereby, the weight of the protective film can be reduced and the protective film can be easily formed. In this case, the resin may be composed of at least one resin selected from an epoxy resin, a phenol resin, a furan resin, a fluororesin, and nylon.

  The protective film 114 is made of a metal or a metal compound. Thereby, the strength of the protective film 114 can be improved. Further, since the protective film 114 becomes conductive, the function of electrostatic grounding can be added to the protective film 114. In this case, the metal or metal compound may contain at least one element selected from Ni, Zn, Cr, Cu, Ag, Fe, Sn, and Mg. Further, a black plating film or a needle-like plating film may be formed as the protective film 114 by this metal or metal compound. Thereby, since the reflectance of light can be reduced, it is possible to provide a floating unit suitable for a line that requires a conveyance path having a low reflectance in the exposure process.

  Further, the protective film 114 may be made of at least one of glassy carbon and diamond-like carbon. As a result, the protective film 114 becomes conductive, thereby adding an electrostatic grounding function. Moreover, since the reflectance of light can be reduced, it is possible to provide a floating unit that is more suitable for a line that requires a low-reflectance conveyance path in the exposure process.

  Further, the protective film 114 may be made of a material containing silicon dioxide such as glass. Thereby, the chemical stability of the protective film can be achieved.

[Fourth Embodiment]
Next, a fourth embodiment will be described. As shown in FIG. 13, in the levitation unit according to the present embodiment, the arrangement positions of the porous plate 76 and the non-porous plate 77 are different even in the chambers adjacent to each other in the direction orthogonal to the transport direction, as compared with the first embodiment. A staggered arrangement is used to alternate.
Thereby, a workpiece | work can be conveyed in the more stable state.

[Fifth Embodiment]
Next, a fifth embodiment will be described. As shown in FIG. 14, in the levitation unit according to the present embodiment, one porous plate 76 and two non-porous plates 77 are repeatedly arranged in the workpiece conveyance direction U as compared to the first embodiment. ing.
Thereby, compared with 1st Embodiment, the arrangement | positioning number of the porous board 76 can further be reduced, and also the flow state of the air ejected to the conveyance road surface F side is too much, and a conveyance state becomes unstable, An increase in running cost is further prevented.

  In the embodiment shown in FIG. 1 to FIG. 14, the floating units 10 and 40 of the present invention are incorporated in the exposure apparatus, but the present invention is not limited to this and other than the exposure apparatus, For example, it can be used for an apparatus for transporting a glass substrate, such as an inspection apparatus, a defect repair apparatus, and a coater apparatus.

  Furthermore, in embodiment shown in FIGS. 1-14, although demonstrated as an example the glass substrate as a to-be-conveyed body conveyed by the floating units 10 and 40, this invention is not limited to this, For example, You may convey to-be-conveyed bodies other than a glass substrate, such as a resin plate and a metal plate.

It is a perspective view which shows the exposure apparatus with which the floating unit which concerns on 1st Embodiment, and the floating unit which concerns on 2nd Embodiment were assembled | attached. It is a side view which shows the exposure apparatus with which the floating unit which concerns on 1st Embodiment, and the floating unit which concerns on 2nd Embodiment were assembled | attached. It is a top view which shows the exposure apparatus with which the floating unit which concerns on 1st Embodiment, and the floating unit which concerns on 2nd Embodiment were assembled | attached. It is a perspective view of the levitation unit concerning a 1st embodiment. It is a disassembled perspective view of the levitation unit concerning a 1st embodiment. It is a perspective view which shows the attachment structure of the side plate of the floating unit which concerns on 1st Embodiment. It is an enlarged plan view of the chamber of the levitation unit according to the first embodiment. It is a sectional side view of the levitation unit concerning a 1st embodiment. It is a sectional side view of the levitation unit concerning a 1st embodiment. It is a top view of the chamber of the levitation unit concerning a 2nd embodiment. It is a top view of the porous board of the levitation unit concerning a 2nd embodiment. It is a perspective view which shows that the protective film is formed in the porous board with the floating unit which concerns on 3rd Embodiment. It is a perspective view which shows the exposure apparatus with which the floating unit which concerns on 4th Embodiment, and the floating unit which concerns on 2nd Embodiment were assembled | attached. It is a perspective view of the levitation unit concerning a 5th embodiment. It is a perspective view which shows the conventional floating unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Levitation unit 36 Chamber 37 Ceiling wall 40 Levitation unit 72 Vent hole 74 Vent hole 76 Porous board (porous body)
77 Non-porous plate (non-porous body)
80 Chamber 82 Porous plate (porous body)
114 Protective film 116 Porous plate (porous body)
F Transport road surface P Glass substrate (workpiece)
U Work transfer direction

Claims (8)

A chamber in which an airtight space is formed and a fluid passage hole communicating with the airtight space is formed in the ceiling wall;
A porous body having a lower side fixed to the ceiling wall and an upper side forming a conveyance path for conveying a workpiece;
A non-porous body which is fixed to the ceiling wall on the lower side and forms a conveyance path for conveying a work on the upper side;
The floating unit is characterized in that the porous body and the non-porous body are disposed so that the porous body is discontinuously disposed in the workpiece conveyance direction.   The levitation unit according to claim 1, wherein the porous body and the non-porous body are alternately arranged in a workpiece conveyance direction.   The levitation unit according to claim 1 or 2, wherein the porous body and the non-porous body are detachable from the ceiling wall. A plurality of the conveyance paths are formed by providing a plurality of the chambers in parallel along the workpiece conveyance direction,
The said conveyance path is arrange | positioned so that the said porous body and the said non-porous body may adjoin in the workpiece conveyance direction, The adjacent conveyance path of any one of Claims 1-3 characterized by the above-mentioned. Levitation unit.   The levitation unit according to claim 1, wherein a protective film is formed on a conveyance path side of the porous body.   An apparatus comprising the levitation unit according to claim 1. It has a porous body that forms a workpiece conveyance path on the upper side, and has a chamber that forms an airtight space communicating with the conveyance path side through the porous body below the porous body,
A non-porous body is disposed so that the chamber is discontinuously disposed in the workpiece transfer direction.   The chamber is provided with a ceiling wall that forms a ceiling side of the hermetic space and is formed with a fluid passage hole communicating with the hermetic space, and the porous body is disposed above the ceiling wall. The device of claim 7.

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