JP4789399B2 - Levitation unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a levitation unit that floats while maintaining high flatness of a large substrate used for, for example, a liquid crystal display (LCD), a plasma display panel (PDP), and a color filter, and a substrate inspection apparatus using the levitation unit.
[0002]
[Prior art]
Currently, in the field of large displays, glass substrates used in flat display panels (FDP) such as LCDs and PDPs tend to become larger and larger in order to meet demands for larger screens and cost reductions. In the FDP manufacturing process, rollers are used to convey large glass. Recently, friction between a large substrate and a roller has become a problem, and it is considered that the glass substrate is floated and conveyed.
[0003]
In the glass substrate inspection process, the glass substrate is imaged by combining an optical system and a CCD camera, and the image data acquired by the imaging is analyzed to inspect the glass substrate.
[0004]
On the other hand, in the pattern generation process of the glass substrate, a pattern is formed by repeating each process of film formation → exposure → development → etching as in the process of generating the semiconductor circuit. Since the glass substrate has low rigidity, the glass substrate may be warped under the influence of a difference in thermal expansion coefficient from the generated thin film, processing at a high temperature, or the like. As the size of the glass substrate increases, the warpage tends to increase more and more.
[0005]
When the glass substrate is inspected by the magnifying optical system, if the glass substrate is warped, the image of the glass substrate is blurred without being focused. Further, when a glass substrate is inspected by a reduction optical system, if the glass substrate is warped, an interference image and a luminance distribution cannot be obtained accurately.
[0006]
For example, Patent Document 1 discloses a technique for eliminating the influence of the warp of the glass substrate. In this Patent Document 1, both ends of a thin plate such as a liquid crystal substrate are gripped and transferred onto a surface plate, the transferred thin plate is floated by an air slider, and air blowing and suction are performed by an air bearing at an inspection station. At the same time, the flying height of the thin plate is adjusted.
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-181714
[Problems to be solved by the invention]
However, in Patent Document 1, since the upper surfaces of the air bearing arranged at the inspection station and the air slider that floats and conveys the thin plate are the same, if the air suction force is increased in order to correct a large warp, The balance with the air discharge force will be lost. Thus, when the negative pressure by suction becomes larger than the positive pressure by discharge, the glass substrate may be adsorbed and fixed by the negative pressure.
[0009]
Moreover, since the line light source for transmitted illumination is provided in the width direction of the conveyance path which conveys a glass substrate by air in patent document 1, there exists a possibility that an air conveyance path may interrupt in the width direction and the front-end | tip of a glass substrate may collide. is there.
[0010]
Then, an object of this invention is to provide the floating unit which can correct | amend a glass substrate to high flatness, and a board | substrate inspection apparatus using the same.
[0011]
[Means for Solving the Problems]
The present invention is provided with a plurality of floating blocks for blowing air to float the substrate, and between the floating blocks, the upper surface position is formed lower than the upper surface position of the floating block, and air suction is performed to remove the substrate. A levitation unit having a suction block that draws in a non-contact manner, and provided a gap for supplying air in the atmosphere to the air suction portion of the suction block between each of the levitation blocks and the suction block It is.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
[0014]
FIG. 1 is an external configuration diagram of the floating unit. On the base 1, a plurality of floating blocks 2, 3 and a suction block 4 are provided between the floating blocks 2, 3. The floating blocks 2 and 3 are each formed in a rectangular parallelepiped shape, and buffer spaces 5 and 6 for equalizing the air blowing pressure are formed therein as shown in FIG.
[0015]
The upper surface positions of the floating blocks 2 and 3 are formed at the same height position. A plurality of air blowing holes 7, 8, 9, and 10 are provided on the upper surfaces of the floating blocks 2 and 3, respectively. These air blowing holes 7, 8, 9, and 10 are not limited to two on the upper surfaces of the floating blocks 2 and 3, and may be one or a plurality of two or more.
[0016]
As shown in FIG. 2, air supply holes 11 and 12 are provided in the portion of the base 1 where the floating blocks 2 and 3 are provided. A compressed air supply source 13 is connected to the air supply holes 11 and 12. The compressed air source 13 supplies compressed air at a predetermined air pressure P ₁ in the buffer space 5,6 via respective air supply holes 11 and 12. The compressed air supply source 13 is capable of adjusting the air pressure P ₁ of the compressed air.
[0017]
The suction block 4 is formed in a rectangular parallelepiped shape, and a concave suction pad 14 is provided on the top thereof. The upper surface height position of the suction pad 14 is provided by a level difference L lower than the height position of the upper surface of each floating block 2, 3.
[0018]
The suction pad 14 is provided with a pad wall 16 over the entire circumference of the outer peripheral edge of the groove bottom 15 formed in a rectangular shape to form a pad groove, and an air suction hole 17 is provided in the groove bottom 15 of the pad groove. ing. The air suction holes 17 may be provided at the central portion or both ends of the groove bottom portion 15, and the number of the air suction holes 17 is not limited to one, and a plurality of air suction holes 17 may be provided.
[0019]
An air suction hole 18 is provided in the portion of the base 1 corresponding to the air suction hole 17 of the suction block 4 as shown in FIG. A negative pressure air supply source 19 is connected to the air suction hole 18.
[0020]
Negative pressure air supply source 19 exhausts the air in the suction pad 14 at a predetermined air negative pressure P ₂ through the air suction holes 17, 18. The negative pressure air supply source 19 is capable of adjusting the air negative pressure P _2.
[0021]
In addition, gaps 20 and 21 for supplying air in the atmosphere to the upper surface of the suction pad 14 of the air suction block 4 are provided between the floating blocks 2 and 3 and the suction block 4. The gaps 20 and 21 may be any distance that can sufficiently supply air to the air suction block 4. Ventilation holes 22 and 23 are provided in portions of the base 1 corresponding to the gaps 20 and 21, respectively. One or a plurality of these air holes 22 and 23 are provided, and are formed to have a diameter and a number sufficient to supply air to the air suction block 4.
[0022]
Next, the operation of the apparatus configured as described above will be described.
[0023]
The compressed air supply source 13 supplies compressed air at a predetermined air pressure P ₁ into the buffer spaces 5 and 6 through the air supply holes 11 and 12. These compressed air is equalized to the air pressure distribution of the air pressure P ₁ in the buffer spaces 5 and 6 and blown up from the air blowing holes 7, 8, 9, and 10 to float the glass substrate 24. .
[0024]
On the other hand, the negative pressure air supply source 19 exhausts air at a predetermined negative air pressure P ₂ through the air suction holes 17 and 18. Thereby, the suction pad 14 sucks air from the entire inside of the pad groove, and exhausts air from the pad groove through the air suction holes 17 and 18. As a result, the entire surface of the suction pad 14 on the opening side becomes a negative pressure due to air suction, and the glass substrate 24 is sucked.
[0025]
When the glass substrate 24 is conveyed in the same direction as the longitudinal direction of the pad groove of the suction pad 14 as shown in FIG. 1, the glass substrate 24 is blown from the air blowing holes 7, 8, 9, 10. As a result, an air layer is formed between the glass substrate 24 and the upper surfaces of the floating blocks 2 and 3 and floats on the floating blocks 2 and 3.
[0026]
At the same time, the glass substrate 24 is drawn toward the suction pad 14 by the negative air pressure sucked through the air suction holes 17 and 18 from the entire surface of the pad groove of the suction pad 14. The negative air pressure at this time is applied to the entire surface of the pad groove of the suction pad 14 with respect to the glass substrate 24 because the glass substrate 24 floats slightly above the suction pad 14.
[0027]
At this time, the air flow is such that the air blown from the air blowing holes 7, 8, 9, 10 is blown to the glass substrate 24, and between the upper surfaces of the floating blocks 2, 3 and the glass substrate 24. It flows to the upper surface of the suction pad 14 and is sucked into the air suction holes 17 and 18 through the pad groove of the suction pad 14.
[0028]
To correct the warpage occurring in the glass substrate 24, increasing the air negative pressure P ₂ to exhaust through air suction holes 18 and the air suction hole 17 by negative pressure air supply source 19, the suction pad formed in a rectangular shape The negative air pressure sucked through the entire surface of the pad groove 14 increases, and the force pulling the glass substrate 24 toward the suction pad 14 increases.
[0029]
As a result, if the balance between the air pressure blown from the air blowing holes 7, 8, 9 and 10 and the negative air pressure sucked through the suction pad 14 is adjusted, the warp of the glass substrate 24 is corrected. .
[0030]
When the warp amount of the glass substrate 24 is large, the negative air pressure sucked through the suction pad 14 is increased. When the negative air pressure is increased, the glass substrate 24 descends as shown in FIG. 3 and approaches each floating block 2, 3, and the gap between the glass substrate 24 and the upper surface of each floating block 2, 3 becomes narrow.
[0031]
As shown in FIG. 3, air flows at this time from the air holes 22 and 23 of the base 1 to the upper surface of the suction pad 14 through the gaps 20 and 21 between the floating blocks 2 and 3 and the suction block 4. The air is exhausted from the inside of the pad groove of the suction pad 14 through the air suction hole 17 and the air suction hole 18.
[0032]
At this time, the glass substrate 24 floats on the floating blocks 2 and 3 by the air layer blown between the floating blocks 2 and 3 and the glass substrate 24. Further, since the upper surface of the suction pad 14 is provided at a position lower than the upper surfaces of the floating blocks 2 and 3, a gap between the suction pad 14 and the glass substrate 24 is secured, and even if the negative air pressure is increased. The air does not flow from the periphery of the suction pad 14 through this interval, and the suction pad 14 is not blocked by the glass substrate 24.
[0033]
Therefore, in the first embodiment, the space between the suction pad 14 and the glass substrate 24 is ensured more securely than the air layer, and the upper surface of the suction pad 14 is made one step lower than the upper surfaces of the floating blocks 2 and 3, since the interval sufficiently secured between the glass substrate 24, increasing the air negative pressure P ₂ for exhausting the air suction hole 17 in order to correct a large warpage occurs in the glass substrate 24, a glass substrate 24 The air discharge force (positive pressure) and the suction force (negative pressure) do not come into contact with the upper surfaces of the floating blocks 2 and 3 and are not attracted to the suction pad 14 by the blown-up air layer. The flying height of the glass substrate 24 can be controlled with high accuracy.
[0034]
In addition, since the air supply system to the floating blocks 2 and 3 and the air suction system from the suction block 4 are independent from each other, in order to correct the warp of the glass substrate 24, the air blowing pressure and the air suction The force can be adjusted separately with good balance, and the flying height of the glass substrate 24 can be controlled by adjusting the air blowing pressure and the air suction force.
[0035]
Further, the warp can be corrected by adjusting each pressure and balance between air blowing and air suction according to the rigidity of the glass substrate 24. Further, since the floating blocks 2 and 3 and the suction pad 14 can be designed separately, the degree of freedom in design such as the shape of the floating blocks 2 and 3 and the diameter of the suction pad 14 is increased.
[0036]
Since the gaps 20 and 21 are provided between the floating blocks 2 and 3 and the suction block 4, the air suction force from the suction pad 14 is increased in order to correct a large warp generated in the glass substrate 24. However, air can be flowed to the suction pad 14 through the gaps 20 and 21, and the large warp of the glass substrate 24 can be reliably corrected.
[0037]
In addition, since the longitudinal direction of the pad groove of the suction pad 14 is provided in the same direction as the transport direction of the glass substrate 24, even if the end surface of the glass substrate 24 passes during transport, There is no change in the air pressure distribution, and the glass substrate 24 can be stably conveyed without shaking in the vertical direction.
[0038]
Next, a second embodiment of the present invention will be described with reference to the drawings. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0039]
4 and 5 are configuration diagrams of the levitation unit, FIG. 4 is an external configuration diagram, and FIG. 5 is a cross-sectional configuration diagram. In the present embodiment, the floating blocks 2 and 3 and the suction block 4 are brought into surface contact to eliminate the gaps 20 and 21, and a step L is directly provided between the floating blocks 2 and 3 and the suction block 4. Is.
[0040]
With such a configuration, the glass substrate 24 floats above the floating plates 7 and 8 by the air pressure blown from the air blowing holes 7, 8 and 9 and 10. At the same time, the glass substrate 24 is pulled toward the suction pad 14 by the negative air pressure sucked through the air suction hole 17 from the entire surface of the pad groove of the suction pad 14.
[0041]
As shown in FIG. 5, the air flow at this time is such that the air blown from the air blowing holes 7, 8, 9 and 10 is blown to the glass substrate 24 and flows to the suction pad 14, 18 is sucked through.
[0042]
In such a configuration, since the amount of air flowing into the suction pad 14 is reduced by the amount of the gaps 20 and 21 between the floating blocks 2 and 3 and the suction block 4, the negative air pressure of the suction pad 14 is reduced. However, if the glass substrate 24 is thin and the amount of warpage occurring in the glass substrate 24 is small, it is possible to obtain a negative air pressure sufficient to correct the warp.
[0043]
In each of the above embodiments, the suction block 4 is provided between the two floating blocks 2 and 3, but one suction block may be provided adjacent to one floating block. Moreover, although the air levitation method is used as the levitation means of the glass substrate 24, the present invention is not limited to this, and an electrostatic levitation method may be used. Further, not only the method of blowing air from each air blowing hole 7, 8, 9, 10 but each floating plate 7, 8 is replaced with a plate made of a porous member, and uniform pressure is applied from the entire surface of this porous plate. The air may be blown up to float the glass substrate 24.
[0044]
The shape of the suction pad 14 is not limited to a rectangular shape, and may be an elliptical shape. When the glass substrate 24 is transported on the floating device, the ratio of the area of air blowing to the glass substrate 24 and the area of air suction. Any shape that does not change significantly may be used. Thus, if the ratio of the area of air blowing to the glass substrate 24 and the area of air suction does not change significantly, the air pressure distribution does not change even while the end surface of the glass substrate 4 passes in the transport direction, The glass substrate 24 can be stably conveyed without shaking in the vertical direction.
[0045]
Next, a third embodiment of the present invention will be described with reference to the drawings. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0046]
FIG. 6 is a schematic configuration diagram of a substrate inspection apparatus using the levitation unit of each of the above embodiments. The transfer stage 30 is provided with a plurality of air blowing holes 31 and a plurality of air suction holes 32 at predetermined intervals on the upper surface. The glass substrate 24 stably floats above the transfer stage 30 by air blowing from each air blowing hole 31 and air sucking from each air suction hole 32, and the glass substrate 24 is supported by each suction holding mechanism (not shown). Both ends are pulled and conveyed in the direction of the arrow a. The transfer stage 30 is not limited to the air blowing holes 31 and the air suction holes 32, and may be provided with only the air blowing holes 31. Glass with a uniform pressure is blown from the entire surface of the porous member. The substrate 24 may be levitated.
[0047]
The microscope body 33 is provided on a portal arm (not shown), and is movable above the transfer stage 30 in the direction of an arrow B perpendicular to the air transfer direction (A) of the glass substrate 24. A portion observed by the movement of the microscope main body 33 becomes an inspection region for the glass substrate 24.
[0048]
On the upper surface of the transfer stage 30 corresponding to this inspection area, a plurality of levitation units 34 composed of the levitation blocks 2 and 3 and the suction block 4 described in the first or second embodiment are arranged. These floating units 34 are provided such that the longitudinal direction of each pad groove of each suction pad 14 of the suction block 4 is parallel to the air conveyance direction (A) of the glass substrate 24.
[0049]
With such a configuration, the glass substrate 24 is stably floated above the conveyance stage 30 by air blowing from each air blowing hole 31 of the conveying stage 30 and air suction from each air suction hole 32. Then, both end portions are pulled by each suction holding mechanism and are transported at predetermined pitches in the direction of arrow A.
[0050]
On the other hand, by placing the floating unit 34 in the inspection area of the microscope main body 33, the position of the flying height of the glass substrate 24 can be controlled with high precision by blowing and suctioning air, and the level of the glass substrate 24 can be adjusted on the inspection area. High accuracy can be maintained.
[0051]
In the inspection of the glass substrate 24, a magnified image of the microscope main body 33 is observed to detect a defective portion, so that the depth of focus decreases as the magnification of the microscope main body 33 increases. Therefore, if the glass substrate 24 is not leveled, the microscope main body 33 is not focused and an enlarged image of the glass substrate 24 is blurred. However, each floating unit 34 provided in the inspection region of the microscope main body 33 is blurred. Accordingly, the warp of the glass substrate 24 is corrected, and the glass substrate 24 is accurately held horizontally and at a constant height on the inspection region. An enlarged image can be obtained, and the inspection accuracy of the glass substrate 24 can be increased.
[0052]
In the third embodiment, a plurality of levitation units 34 are arranged on the upper surface of the transfer stage 30, but these levitation units 34 may be arranged as shown in FIGS. In the air transfer stage 30 shown in FIG. 7, a plurality of air blowing holes 31 are provided at appropriate intervals, and a plurality of grooves 35 are provided in parallel along the transfer direction (A) of the glass substrate 24. Further, the transfer stage 30 may be formed of a porous member. Each observation hole of the microscope main body 33 on each upper surface divided by each groove 35 of the transport stage 30 is provided with each installation hole 36, and each floating unit 34 is provided in each of the installation holes 36.
[0053]
In the air conveyance stage 30 shown in FIG. 8, the levitation unit 34 is provided in the observation region of the microscope main body 33 on each bottom surface of each groove 35.
[0054]
Even with the arrangement of the levitation unit 34, the same effects as those of the third embodiment can be obtained.
[0055]
The present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.
[0056]
The levitation unit described in each of the above embodiments is not limited to the FDP glass plate substrate inspection apparatus, but can be applied to various substrate transfer lines such as semiconductor manufacturing lines, or color liquid crystal display filter inspection. It can also be applied to a transfer line in the apparatus. Further, when the levitating apparatus described in the above embodiments is applied to the stepper, the exposure process can be performed by levitating and holding the semiconductor substrate on the stage in a non-contact state.
[0057]
【The invention's effect】
As described above in detail, according to the present invention, a floating unit capable of correcting a glass substrate into a flat shape and a substrate inspection apparatus using the same can be provided.
[Brief description of the drawings]
FIG. 1 is an external configuration diagram showing a first embodiment of a levitation unit according to the present invention.
FIG. 2 is a cross-sectional configuration diagram of the unit.
FIG. 3 is a view showing a gap between the glass substrate and the floating plate when the negative air pressure by the suction pad in the unit is increased.
FIG. 4 is an external configuration diagram showing a second embodiment of a levitation unit according to the present invention.
FIG. 5 is a cross-sectional configuration diagram of the unit.
FIG. 6 is a schematic configuration diagram showing a third embodiment of a substrate inspection apparatus using a levitation unit according to the present invention.
FIG. 7 is a view showing a modification of the arrangement of the floating unit according to the present invention in the substrate inspection apparatus.
FIG. 8 is a view showing a modification of the arrangement of the floating unit according to the present invention in the board inspection apparatus.
[Explanation of symbols]
1: base, 2, 3: floating block, 4: suction block, 5, 6: buffer space, 7, 8: floating plate, 9a, 9b, 10a, 10b: air blowing holes, 11, 12: air supply holes , 13: compressed air supply source, 14: suction pad, 15: groove bottom, 16: pad wall, 17, 18: air suction hole, 19: negative pressure air supply source, 20, 21: gap, 22, 23: communication Pore, 24: Glass substrate, 30: Transport stage, 31: Air blowing hole, 32: Air suction hole, 33: Microscope body, 34: Lifting unit, 35: Groove, 40: Base, 41: Porous member 42: groove, 43: air suction part, 44: bottom part, 45: wall, 46: air suction hole, 47: semiconductor wafer.

Claims (2)

A plurality of floating blocks that blow out air and float the substrate;
Provided between these floating blocks, the upper surface position is formed lower than the upper surface position of the floating block, and has a suction block that draws the substrate in a non-contact manner by performing air suction ,
A levitation unit characterized in that a gap for supplying air in the atmosphere to an air suction portion of the suction block is provided between each of the levitation blocks and the suction block . A base for opening each of the gaps and providing each of the floating plates and the suction block;
An air vent provided in the base portion corresponding to each gap, and supplying air to the upper surface of the suction pad of the suction block through each gap;
Floating unit according to claim 1, characterized in that provided.

Images