JP2006281426A - Positioning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positioning device constituted simple and light and capable of realizing positioning with high precision. <P>SOLUTION: It is possible to lighten a surface plate 1 without precisely working the overall upper surface of the surface plate in positioning it in high precision as a moving member 6 is suspended on a supporting plate 3 through sliders 4, 4 and guide rails 5, 5. That is, it is effective to assemble the surface plate 1 by disassembling it and carrying it to a site in setting the positioning device. Additionally, part precision and deformation of supporting legs 2, 2 never affects the positioning. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a positioning device, for example, a positioning device suitable for use in high-precision inspection and processing.

When manufacturing semiconductor wafers, liquid crystal panels, etc., a measuring instrument or tool is mounted on the surface plate on which the object to be measured or the workpiece is placed in order to perform fine pattern exposure or perform inspections. Positioning devices that move are known. In particular, a device that has two legs and moves across an object to be measured or a workpiece is called a gantry type positioning device. Such a gantry-type positioning device is disclosed in Patent Document 1. In the positioning device of Patent Document 1, the slider is guided by a guide element arranged with respect to a surface plate serving as a reference of the device.
JP 2000-15532 A

  By the way, in flat panel displays and the like used for thin TVs that have advanced in recent years, the increase in the size and productivity of the substrate has been remarkable. For example, a glass substrate of 2000 mm × 2000 mm or more has already been adopted in the liquid crystal manufacturing process. There is a need to inspect and process such a glass substrate as an object to be measured or a workpiece.

  However, when the object to be measured or the workpiece is increased in size as described above, the conventional positioning apparatus has a problem that the posture accuracy (particularly pitching accuracy) of the stage during movement greatly affects the machining accuracy. For example, for a workpiece with a size of 200 mm, an inclination with an angle of about 1 second (about 4.8 μrad) can be suppressed to an error of about 1 μm at maximum, whereas with a workpiece with a size of 2000 mm, the inclination with an angle of 1 second However, this causes an error of 10 μm at maximum. An error of up to 10 μm can be a sufficiently large error in manufacturing a flat panel having a line width of μm. Thus, errors are eliminated as much as possible by measures such as detecting and correcting errors and improving the guidance accuracy of the positioning device.

  Here, in order to improve the guiding accuracy of the conventional positioning device, it is necessary to increase the rigidity of the surface of the surface plate and to process the flatness. However, a surface plate that can support a workpiece having a side of 2000 mm has a weight of 10 tons or more, and further weight reduction is desired to facilitate installation. However, even if the weight can be reduced by thinning or the like, the rigidity is lowered by this, so that it becomes difficult to maintain the surface of the surface plate at a high flatness. Moreover, the guide rail which guides a 2000 mm workpiece | work becomes a length of 4000 mm or more, and it is difficult to give a high precision process over the full length.

  Accordingly, an object of the present invention is to provide a positioning device that can achieve highly accurate positioning while having a simple and lightweight configuration.

In order to achieve the above object, the positioning device of the present invention comprises:
A support fixed on the surface plate;
A moving member suspended movably through a linear guide with respect to the support;
Drive means for driving the moving member with respect to the surface plate.

  According to the positioning apparatus of the present invention, the moving member is suspended so as to be movable via the linear guide with respect to the support portion fixed on the surface plate. It is not necessary to machine the whole with high accuracy, the surface plate can be reduced in weight, and the component accuracy and deformation of the support legs do not affect the positioning.

  Furthermore, it is preferable to have an inclination correction unit that corrects the inclination of the moving member with respect to the surface plate because higher-precision positioning can be realized.

  Furthermore, it is preferable that the inclination correction means corrects the inclination of the moving member with respect to the surface plate using gas.

  Furthermore, it is preferable that the tilt correction means corrects the tilt with respect to the surface plate using an elastic force.

  Further, if a vibration isolating member is disposed between the installation surface on which the positioning device is installed and the surface plate, vibration from the installation surface is suppressed from being transmitted to the surface plate. Therefore, it is preferable.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front cross-sectional view of a positioning device according to a first embodiment used for a measuring instrument, and FIG. 2 is a view of the configuration of FIG. 1 taken along line II-II and viewed in the direction of the arrow. However, support legs are omitted.

  In FIG. 1, a pair of support legs 2 and 2 are arranged side by side on a surface plate 1. A support plate 3 is disposed at the upper ends of the support legs 2 and 2 in parallel with the upper surface of the surface plate 1. An image reading device C that reads an image of a glass substrate G that is a work placed on the surface plate 1 and obtains its shape is attached to the support plate 3 so as to hold the flange from above with a holder 3a. .

  On the lower surface of the support plate 3, two sliders 4, 4 are attached in parallel on one side. Guide rails 5 and 5 are engaged with the sliders 4 and 4 so as not to be separable and relatively movable. The guide rails 5 and 5 that constitute the linear guide together with the sliders 4 and 4 are fixed to the upper surface of the plate-like moving member 6 on which the glass substrate G is placed. In particular, in the present embodiment, it is preferable to use a rolling linear guide. In the present embodiment, since the center of gravity with respect to the bearing is moved by the movement of the moving member 6, a higher moment load type guide element is required than usual. Therefore, it is appropriate to provide a contact type rolling linear guide with high moment rigidity. In particular, flexing the slider itself within the bearing is difficult for non-contact bearings. Further, in the case where the moving member 6 is suspended in the vertical direction, a self-supporting rolling linear guide is suitable in consideration of dropping measures in the event of a power failure.

  Between the moving member 6 and the surface plate 1, a linear motor 7 as a driving means is arranged. Examples of the linear motor include a linear induction motor, a linear synchronous motor, a linear pulse motor, a linear direct current motor, and a linear hybrid motor, and any of them can be used, and an example thereof will be described here. FIG. 3 is a view for explaining the principle of the linear motor 7 and corresponds to a view of the configuration of FIG. 1 taken along the line III-III and viewed in the direction of the arrow. In FIG. 3, the magnetic yoke 7a mounted in the U-shaped groove 1a of the cross section of the surface plate 1 has a large number of N poles and S poles (field magnets) arranged alternately at equal pitches along the longitudinal direction. Two rows are arranged opposite to each other. On the other hand, in the armature unit 6a connected to the moving member 6, the armatures 7b having cores are attached in two rows so as to face the N pole and the S pole of the magnetic yoke 7a. In the linear motor 7, when a three-phase alternating current is passed through the core of the armature 7b, a magnetic force is generated between the magnetic yoke 7a and the field magnet, whereby the moving member 6 is driven relative to the surface plate 1. It has come to be. In particular, in the present embodiment, a linear motor is preferable as the driving means. The guide accuracy of the linear guide slider is compensated for the processing site, but the guide accuracy at other locations is not compensated. For this reason, when a ball screw or the like is selected as the driving element, the center of the shaft is touched and the positioning accuracy is degraded. On the other hand, the linear motor can tolerate an error of several μm level, and is suitable for the present embodiment.

  The operation of the positioning device of the present embodiment will be described. When power is supplied to the linear motor 7 with the glass substrate G placed on the moving member 6, the moving member 6 moves relative to the substrate 1 in the left-right direction in FIG. The position of G can be made to face the image reading device C. When inspecting a two-dimensional position, the moving member 6 may be supported by two pairs of guide rails and sliders facing in two directions.

  According to the present embodiment, since the moving member 6 is suspended from the support plate 3 via the sliders 4 and 4 and the guide rails 5 and 5, the entire upper surface of the surface plate 1 is used for highly accurate positioning. The surface plate 1 can be reduced in weight. This is effective when disassembling the surface plate 1 and transporting it to the site where it is assembled. In addition, the component accuracy and deformation of the support legs 2 and 2 do not affect the positioning.

  Further, for example, since the moving member 6 is long, the image reading device C is arranged at the center of the sliders 4 and 4 aligned in the axial direction even if the pitching due to the bending or the movement of the center of gravity occurs. The distance to the target glass substrate G is substantially constant regardless of the pitching, and a highly accurate inspection can be performed. However, when very high-precision inspection or the like is performed, it may be necessary to suppress bending or pitching of the moving member 6. The following embodiments are suitable for such applications.

  FIG. 4 is a cross-sectional view similar to FIG. 2 of the positioning device according to the second embodiment, but the linear motor is omitted. The present embodiment differs from the embodiment shown in FIGS. 1 and 2 only in that a hydrostatic bearing is disposed. Therefore, the same components are denoted by the same reference numerals and description thereof is omitted.

  In FIG. 4, a plurality of hydrostatic bearings 8 are provided on the surface plate 1 along the moving direction of the moving member 6 and with a small gap (exaggerated in the drawing) with respect to the lower surface of the moving member 6. Has been placed. The static pressure bearing 8 constituting the inclination correcting means blows air from a porous static pressure pad 8b installed on the upper surface in the support portion 8a on the substrate 1, and supports the moving member 6 by the static pressure. Is. A pump for supplying air to the static pressure pad 8b and its piping are not shown.

  For example, it is assumed that the right end in the drawing is lowered as shown in FIG. 4 due to play between the sliders 4 and 4 and the guide rails 5 and 5. At this time, since the clearance between the right-side hydrostatic bearing 8 and the moving member 6 is reduced, the static pressure F applied to the moving member 6 from the static pressure pad 8b is increased. Since the static pressure F is used to apply a counterclockwise moment to the moving member 6 and the inclination thereof can be corrected, more accurate positioning can be realized.

  Further, consider the case where the rigidity of the moving member 6 is relatively low. If the hydrostatic bearing 8 is not provided, as shown by a dotted line in FIG. 5, the unsupported both ends are slightly deformed by the dead weight of the moving member 6 so as to hang down. In such a case, the distance between the image reading device C arranged at the center of the sliders 4 and 4 aligned in the axial direction and the glass substrate (not shown) to be inspected is closer, and the positioning is highly accurate. I can't plan.

  On the other hand, when the static pressure bearings 8 and 8 are arranged on the lower surface of the moving member 6 on both sides of the sliders 4 and 4 in the moving direction, as shown by the solid line in FIG. Since the moment is applied so as to be lifted and deformed, the center of the moving member 6 is displaced downward by Δ using the sliders 4 and 4 as fulcrums. That is, the deflection of the moving member 6 can be corrected, and the distance between the image reading device C and the glass substrate (not shown) to be inspected can be held with higher accuracy.

  6 and 7 are sectional views similar to FIGS. 1 and 2 of a positioning device according to a modification. This embodiment is different from the embodiment shown in FIG. 5 only in that a hydrostatic bearing 8 ′ for applying a static pressure to the surface plate 1 is attached to the lower surface near both ends of the moving member 6. The common components are denoted by the same reference numerals and the description thereof is omitted. In the case of the positioning device of FIG. 5, the deformation mode changes depending on the movement of the moving member 6, but according to the present modification, the static pressure bearing 8 ′ that is the inclination correcting means moves together with the moving member 6. Regardless of the position, the distance between the image reading device C and the glass substrate (not shown) to be inspected can be more accurately maintained.

  FIG. 8A is a sectional view similar to FIG. 2 of the positioning device according to the third embodiment, but the linear motor is omitted. FIG. 8B is a diagram in which the configuration of FIG. 8A is cut along the VB-VB line and viewed in the direction of the arrow. The present embodiment differs from the embodiment shown in FIGS. 1 and 2 only in that the suction portion is arranged, and therefore, the description of the common configuration is omitted by attaching the same reference numerals.

  In FIG. 8, a plurality of suction portions 9 are arranged on the surface plate 1 along the moving direction of the moving member 6 and with a small gap (exaggerated in the drawing) with respect to the upper surface of the moving member 6. Has been. The suction part 9 constituting the inclination correction means has a cylindrical part 9a having a through hole 9c attached to the support plate 3 in the center and an exhaust pump P connected to the through hole 9c of the hollow cylindrical part 9a. Yes.

  For example, it is assumed that the right end in the drawing is lowered as shown in FIG. 5 due to play between the sliders 4 and 4 and the guide rails 5 and 5. At this time, since the clearance between the lower end surface of the cylindrical portion 9a of the suction portion 9 on the right side and the moving member 6 is increased, the pressure in the through hole 9c of the cylindrical portion 9a is controlled and applied to the moving member 6. It is desirable to increase the suction force F (see FIG. 8B). Since the suction force F can be used to apply a moment to the moving member 6 to correct the inclination, more accurate positioning can be realized. In addition, it is arbitrary to use the suction part 9 in combination with the hydrostatic bearing shown in FIG.

  FIG. 9A is a cross-sectional view similar to FIG. 1 of the positioning device according to the fourth embodiment, and FIG. 9B is an enlarged view of the arrow IXB portion of the configuration of FIG. FIG. The present embodiment differs from the embodiment shown in FIGS. 6 and 7 only in that a support device is disposed in place of the hydrostatic bearing, so that the same reference numerals are given to the common configurations. Omitted.

  In FIG. 9A, two rows of shallow grooves 1 a ′ and 1 a ′ are formed on the surface plate 1 along the moving direction of the moving member 6. Support devices 10 and 10 are disposed in the grooves 1a 'and 1a'. Only one support device 10 will be described, but the configuration is the same for both.

  In FIG. 9B, the support device 10 is fixed to the frame 10a having a pair of walls arranged on the upper surface, two rows of guide rails 10b and 10b arranged on the bottom surface of the groove 1a ′, and the lower surface of the frame 10a. The sliders 10c and 10c are movable along the guide rails 10b and 10b, the leaf spring 10d is bridged to the wall of the frame 10, and the support 10e is connected to the leaf spring 10d and the lower surface of the moving member 6.

  According to the positioning device of FIG. 9, the support devices 10 and 10 that are inclination correction means move together with the moving member 6 and suppress deformation of the moving member 6 by the elastic force of the leaf springs 10d and 10d. Regardless, the distance between the image reading device C and the glass substrate G to be inspected can be held with higher accuracy. In order not to deteriorate the guide accuracy of the moving member 6 by the sliders 4 and 4 and the guide rails 5 and 5, the guide accuracy of the sliders 10c and 10c and the guide rails 10b and 10b may be increased, but the grooves 1a ′, In order to eliminate the influence of the surface accuracy of 1a ′, the elastic coefficient of the leaf spring 10d may be lowered to some extent.

  FIG. 10 is a cross-sectional view similar to FIG. 1 of the positioning device according to the fifth embodiment, and FIG. 11 is a cross-sectional view similar to FIG. 2 of the positioning device according to the fifth embodiment. In the present embodiment, the linear motor 7 is fixed to a dedicated surface plate 1 ′ disposed on the installation surface G as compared with the embodiment shown in FIGS. On the other hand, the surface plate 1 is arranged with respect to the ground plane G through a vibration isolator 11 made of rubber or the like. Support legs 2 are arranged on the surface plate 1. The dedicated surface plate 1 ′ is installed in the opening of the surface plate 1, and the two are not in contact with each other. About another common structure, description is abbreviate | omitted by attaching | subjecting the same code. According to the present embodiment, it is possible to suppress transmission of the driving reaction force generated during the operation of the linear motor 7 to the surface plate 1. This can suppress the vibration from being transmitted to the image reading device C through the support leg 2 and the support plate 3. That is, it is possible to shorten the positioning time between the image reading device C and the glass substrate G that is a workpiece and improve the positioning accuracy.

  The present invention has been described above with reference to the embodiments. However, the present invention should not be construed as being limited to the above-described embodiments, and can be modified or improved as appropriate.

It is front sectional drawing of the positioning device of 1st Embodiment. It is the figure which cut | disconnected the structure of FIG. 1 by the II-II line | wire, and looked at the arrow direction. FIG. 3 is an enlarged view of an arrow III part of the configuration of FIG. 2 and is a diagram for explaining the principle of the linear motor 7. It is sectional drawing similar to FIG. 2 of the positioning device concerning 2nd Embodiment. It is a figure which shows the modification of this Embodiment. It is a figure which shows the modification of this Embodiment. It is the figure which cut | disconnected the structure of FIG. 7 by the VII-VII line and looked at the arrow direction. It is a figure which shows the positioning device concerning 3rd Embodiment. It is a figure which shows the positioning device concerning 4th Embodiment. It is a figure which shows the positioning device concerning 5th Embodiment. It is the figure which cut | disconnected the structure of FIG. 10 by the XI-XI line and looked at the arrow direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Surface plate 2, 2 Support leg 3 Support plate 4, 4 Slider 5, 5 Guide rail 6 Moving member 7 Linear motor 8 Static pressure bearing 9 Suction part 10 Support apparatus 11 Anti-vibration rubber G Glass substrate P Exhaust pump

Claims (5)

A support fixed on the surface plate;
A moving member suspended movably through a linear guide with respect to the support;
And a driving means for driving the moving member with respect to the surface plate.   The positioning apparatus according to claim 1, further comprising an inclination correction unit that corrects an inclination of the moving member with respect to the surface plate.   The positioning apparatus according to claim 2, wherein the inclination correcting unit corrects an inclination of the moving member with respect to the surface plate using a gas.   The positioning apparatus according to claim 2, wherein the inclination correction unit corrects an inclination with respect to the surface plate using an elastic force. The positioning device according to any one of claims 1 to 4, wherein a vibration-proof member is disposed between an installation surface on which the positioning device is installed and the surface plate.

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