JP4993137B2 - Surface plate fixing structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface plate fixing structure capable of efficiently cooling, without increasing weight, without requiring a highly accurate temperature adjustment, without generating strain even if linear expansion coefficients of a surface plate and a base are different. <P>SOLUTION: An attachment 14 is used for fixing the surface plate 12 for movably supporting a stage 11 to the base 13. The attachment 14 is positioned in three places at an equal angle interval with the center as the rotational center at an equal distance from the center of a fixing surface 12a of the surface plate 12, and the surface plate 12 is fixed to the base 13 via the attachment 14. The respective attachments 14 are formed lower than rigidity of the surface plate 12 in rigidity in the direction along a straight line of connecting its positioned and the center of the fixing surface 12a of the surface plate 12, and when the temperature rises, even if a difference is caused in the linear expansion between the surface plate 12 and the base 13, its difference is absorbed by the attachment 14. The surface plate 12 and the base 13 are connected in a central position of the fixing surface 12a, and a support 41 is arranged for absorbing relative swinging in the X axis, Y axis directions of the fixing surface between both, and positional dislocation of the center of the fixing surface by a lateral load is eliminated. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a surface plate fixing structure that fixes a surface plate that supports a positioning stage that holds an object to be inspected in an inspection apparatus or the like to a base.

In an inspection apparatus or the like, a positioning stage that holds an object to be inspected is fixed to a surface plate, and this surface plate is fixed to a base.
By the way, in a positioning stage in a semiconductor inspection apparatus, it is necessary to position a semiconductor wafer as an object to be inspected with extremely high accuracy, for example, nano-order positional accuracy. And the base which fixes the surface plate by which such a stage is supported and fixed may be formed with the material from which a linear expansion coefficient differs from a surface plate.
Such a stage support device is schematically shown in FIG.
In this figure, 51 is a positioning stage for holding an object to be inspected, and this stage 51 is supported and fixed on a surface plate 52, and at least the X-axis and Y-axis directions on the surface of the surface plate (in the left-right direction in the figure and on the illustrated surface) (Vertical direction). The surface plate 52 is fixed to the base 53 using a plurality of bolts 54.
Here, if the linear expansion coefficients of the surface plate 52 and the base 53 (each material) are different as described above, for example, if the linear expansion coefficient of the surface plate 52 is larger than the linear expansion coefficient of the base 53, the temperature rises. Distortion is generated as shown in FIG. In the illustrated example, distortion in the order of microns (Z-axis direction error α, yaw / pitch direction error β) occurs. For this reason, high-precision, in other words, high temperature maintenance is required.

  As a similar technique capable of solving the above-described problem of distortion generation, there has conventionally been one described in Patent Document 1. This is related to the support structure for precision instruments, in which two or more plates made of materials having different expansion coefficients are stacked, and the plates are stacked so that the expansion coefficients of the plates are sequentially different.

Japanese Patent Laid-Open No. 11-84038

  However, in the prior art described in Patent Document 1, the entire weight is increased, and the surface of the intermediate layer plate cannot be cooled, so that efficient cooling cannot be performed.

  The present invention has been made in view of the above circumstances, and does not cause distortion even if the linear expansion coefficients of the surface plate and the base are different. Therefore, high-precision temperature adjustment is not required, and the weight is reduced. It is an object of the present invention to provide a surface plate fixing structure that can be efficiently cooled without increasing the size and without disturbing the cooling action.

The said subject is solved by making a surface plate fixing structure the structure of each following aspect.
As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is merely for the purpose of facilitating the understanding of the present invention, and the technical features described in this specification and combinations thereof should not be construed as being limited to those described in the following sections. . In addition, when a plurality of items are described in one section, it is not always necessary to employ the plurality of items together, and it is also possible to take out only a part of the items and employ them.

Of following sections (1) term in the claim 1, (2) term in claim 2, item (4) to the claim 3, (5) term in claim 4, each corresponding To do. Item ( 3 ) is not a claimed invention.

(1) A surface plate fixing structure for fixing to a base a surface plate that movably supports the positioning stage, and the surface plate is equidistant from the center of the fixing surface of the surface plate to the base, And it is fixed to the base via a plurality of attachments each positioned at a plurality of positions at equal angular intervals with the center as the rotation center, and each attachment has its position and the center of the fixed surface of the surface plate. The rigidity in the direction along the straight line to be connected is lower than the rigidity of the surface plate, and the attachment of each attachment to the surface plate and the base is fastening by a fastener, plate fixing structure, wherein Rukoto opening portion is formed for the fastening operation of the fastener.
With respect to a positioning stage that moves in two axial directions (including the rotation direction) of the X axis and the Y axis if attachments are placed at three positions spaced 120 ° apart from the center of the fixed surface to the base of the surface plate, A minimum effect can be achieved with the minimum number of attachments.
In a positioning stage that moves only in one axial direction, the attachments may be placed in at least two places spaced by 180 ° with the center of the surface fixed to the base of the surface plate as the center of rotation.
As the fastener, a bolt, particularly a hexagon socket head bolt, is preferable. In this case, the opening functions as a space through which the tip of the hexagon stick wrench passes to the hexagon hole of the bolt when the bolt is fastened (or loosened). .
(2) Each attachment is rigid in the direction along the rotation direction with the center of the fixed surface of the surface plate as the center of rotation, and in the direction along the straight line connecting the position of the attachment and the center of the fixed surface of the surface plate. The platen fixing structure according to item (1), characterized in that the platen has a higher rigidity.
The rigidity of the attachment refers to the rigidity of the entire attachment.
( 3 ) The surface plate fixing structure according to (1) or (2) , wherein each attachment is positioned at a vessel point of the surface plate.
According to the surface plate fixing structure described in the item ( 3 ), it is possible to support the surface plate with the smallest total length error.
( 4 ) The surface plate and the base are connected to each other at the center position of the fixed surface to the base of the surface plate to absorb relative shaking in the X-axis and Y-axis directions of the fixed surface between the surface plate and the base. characterized by comprising a support (1) term, (2) or (3) plate fixing structure of the mounting serial to term.
( 5 ) The support is divided into two parts, that is, an upper connecting part and a lower connecting part, and both connecting parts are integrated with a flexible disk interposed therebetween ( 4 ). The platen fixed structure described in 1.
The flexibility of the disc can be adjusted by selecting the material and setting the thickness for the area. Usually, a thin disk is used because the area cannot be increased.

According to the invention described in item (1), in the surface plate fixing structure in which the surface plate that movably supports the positioning stage is fixed to the base, distortion occurs even if the linear expansion coefficients of the surface plate and the base are different. Therefore, highly accurate temperature adjustment is not required, the weight is not increased, and cooling can be efficiently performed without impeding the cooling action.
Furthermore , the fixing work to the base of the surface plate using an attachment becomes easy.
According to the invention described in the item (2), the vibration of the surface plate due to acceleration / deceleration during the movement of the stage can be reduced.
According to the invention described in ( 4 ), it is possible to eliminate the shaking of the fixed surface to the base of the surface plate in the X-axis and Y-axis directions and the positional deviation of the fixed surface center.
According to the invention described in the item ( 5 ), there is a margin for setting the height of the support relative to the height of the attachment, and for adjusting the height of the support on the surface plate and bolting to the base. Can do.
Since the invention described in item ( 3 ) is not the present invention (the invention described in the claims), the effect is described in the column of means for solving the above problems.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol shows the same or an equivalent part between each figure.
FIG. 1 is a front view showing a stage support device to which a first embodiment of a surface plate fixing structure according to the present invention is applied, and FIG. 2 is a cross-sectional view taken along line AA in FIG.
As shown in FIG. 1, the stage support device is a positioning stage (hereinafter, stage) that holds the workpiece W so as to be movable in at least the X-axis and Y-axis directions (the left-right direction in the figure and the direction perpendicular to the illustrated surface). This is a device that supports 11 and includes a surface plate 12 and a base 13.
Here, the stage 11 is supported and fixed on the upper surface of the surface plate 12, and the surface plate 12 is fixed on the base 13. The surface plate 12 is fixed to the base 13 by a surface plate fixing structure described below.

That is, in the first embodiment, the surface plate fixing structure is an attachment 14 taken out and enlarged in FIG. 3 in the first embodiment, and the surface plate 12 is fixed to the base 13 via the attachment 14. This fixing is performed by fastening using a fastener, in the illustrated example, a bolt 15.
As can be seen from FIGS. 3 and 2, the attachment 14 has a pair of circular upper surface plate 14a and lower surface plate 14b facing each other at a predetermined interval, and a pair of the upper surface plate 14a and the lower surface plate 14b that maintain the above-mentioned distance. It consists of a spacing plate 14c.

The pair of spacing plates 14c are positioned so as to face each other with a through hole 14d drilled at each central position of the upper surface plate 14a and the lower surface plate 14b. The mutual distance between the pair of spacing plates 14c is such that bolts 15 are inserted through the through holes 14d of the upper surface plate 14a and the lower surface plate 14b, and the upper surface plate 14a is fastened to the surface plate 12 and the lower surface plate 14b is fastened to the base 13. It functions as an opening 14e for work and facilitates bolt fastening work.
In the illustrated example, the bolt 15 is a hexagon socket head cap screw, and the tip of a hexagon stick wrench that is tightened or loosened can be easily fitted into the hexagon socket 15a of the bolt 15 through the open portion 14e.

As can be seen from FIG. 2, the attachment 14 is at an equal distance L1 from the center O of the fixed surface (the lower surface in the drawing) 12a to the base 13 of the surface plate 12, and is equally spaced from the center O as the rotation center. Each is positioned at a plurality of positions at θ1. In the example shown in the figure, each of the three centers is positioned at 120 ° (= θ1) intervals with the center O as the rotation center. Further, each attachment 14 is configured to have a rigidity that is lower than the rigidity of the surface plate 12 in the direction along the straight line L0 connecting the position and the center O of the fixed surface 12a of the surface plate 12. .
The reason for this is that even if the surface plate 12 is deformed due to the difference in linear expansion coefficient between the surface plate 12 and the base 13 (each material), the position in the yaw / pitch direction is secured while securing the position from the center O. This is because the error is set to 0 and the displacement in the Z-axis direction is remarkably reduced.
FIGS. 4A and 4B schematically show this state. FIG. 4A shows a state where the surface plate 12 and the base 13 are not affected by the difference in linear expansion coefficient. 4B, the temperature rises to cause linear expansion. At this time, even if the linear expansion coefficient of the surface plate 12 is larger than the linear expansion coefficient of the base 13, the attachment 14 absorbs the difference, and FIG. It shows that the distortion (Z-axis direction error α, yaw / pitch direction error β) as shown in b) does not occur.

  Each attachment 14 has the following rigidity in the direction along the rotation direction with the center O of the fixed surface 12a of the surface plate 12 as the rotation center. That is, the rigidity is higher than the rigidity in the direction along the straight line L0 connecting the position of the attachment 14 and the center O of the fixed surface 12a of the surface plate 12. This is to reduce vibration of the surface plate 12 due to acceleration / deceleration during the movement of the stage 11.

The number of the attachments 14, the distance L1 from the center O of the fixed surface 12a to the base 13 of the surface plate 12, and the angular interval θ1 with the center O as the rotation center are limited to the example shown in FIG. Of course, it is not done. Any of the configurations that are positioned at a plurality of positions at the same distance L1 from the center O of the fixed surface 12a to the base 13 of the surface plate 12 and at the same angular interval θ1 with the center O as the rotation center. Good.
If the position of the attachment 14 can be set at the vessel point of the surface plate 12, the attachment 14 is positioned at the vessel point. Positioning at the Bessel point enables support that minimizes the error in the overall length of the surface plate 12.

As described above, in the first embodiment, the attachment 14 is used as the surface plate fixing structure for fixing the surface plate 12 that movably supports the stage 11 to the base 13, and the attachment 14 is arranged and configured as follows. . In other words, the surface plate 12 is attached via the attachments 14 positioned at three positions which are at the same distance L1 from the center O of the fixed surface 12a of the surface plate 12 and at an equal angular interval of 120 ° with the center O as the rotation center. Was fastened and fixed to the base 13. Each attachment 14 is configured to have rigidity lower than the rigidity of the surface plate 12 in the direction along the straight line L0 connecting the position and the center O of the fixed surface 12a of the surface plate 12.
According to this, even if the surface plate 12 is deformed (thermal expansion) due to the difference in linear expansion coefficient between the surface plate 12 and the base 13, the error in the yaw / pitch direction is reduced while securing the position from the center O. In addition, the displacement in the Z-axis direction can be significantly reduced. Therefore, highly accurate temperature adjustment, in other words, high maintenance costs are not required. Furthermore, it is lighter than the prior art in which plates of materials having different expansion coefficients are stacked, and ventilation for temperature adjustment between the surface plate 12 and the base 13 is possible and cooling can be performed efficiently.

Further, according to the first embodiment, the rigidity of each attachment 14 in the direction along the rotation direction with the center O of the fixed surface 12a of the surface plate 12 as the rotation center connects the position of the attachment 14 and the center O. Since the configuration is higher than the rigidity in the direction along the straight line L0, the vibration of the surface plate 12 due to acceleration / deceleration during the movement of the stage 11 can be reduced.
Furthermore, according to the first embodiment, since the attachment 14 is provided with the opening 14e for bolt fastening work, the work of fastening the upper surface plate 14a to the surface plate 12 and the lower surface plate 14b to the base 13 by the bolts 15, That is, it becomes easy to fix the surface plate 12 to the base 13 using the attachment 14.

Next, a second embodiment of the present invention will be described.
FIG. 6 is a front view showing a stage support device to which the second embodiment of the surface plate fixing structure according to the present invention is applied, and FIG. 7 is a sectional view taken along the line BB in FIG.
As shown in FIGS. 6 and 7, the second embodiment includes a support body 41 that connects the surface plate 12 and the base 13. The connection by the support 41 is performed by fastening using a fastener, for example, a bolt 15 in the illustrated example.

As shown in FIG. 8 and enlarged, the support 41 connects the upper and lower mounting bases 41a and 41b for bolting separately to the surface plate 12 and the base 13, and the upper and lower mounting bases 41a and 41b. Connecting portion 41c. In the illustrated example, the connecting portion 41c has a cylindrical shape, the upper mounting base portion 41a has a disk shape so as to close the upper end of the cylindrical connecting portion 41c, and the lower mounting base portion 41b starts from the lower end of the cylindrical connecting portion 41c. It has a hook-like shape extending around and is integrally formed.
The upper mounting base 41a has one through hole 41d and the lower mounting base 41b has two to four through holes 41d. Bolts 15 are inserted into the through holes 41d so that the upper mounting base 41a is fixed to the surface plate. 12, the base plate 12 and the base 13 are connected to each other by fastening the lower mounting base 41 b to the base 13.
As can be seen from FIG. 6, the height of the support 41 is the same as the height of the attachment 14.

As can be seen from FIG. 7, the support 41 is positioned at the center position of the fixed surface 12 a to the base 13 of the surface plate 12, and connects the surface plate 12 and the base 13 at the same position.
Further, the support 41 is made of a flexible material by selecting a material, setting each part size, etc., so that the fixed surface 12a between the surface plate 12 and the base 13 is relatively fixed in the X-axis and Y-axis directions. It is made possible to absorb typical shaking (rolling).

The reason for this configuration is as follows.
In the first embodiment, when the stage 11 or the like with high acceleration / deceleration load is mounted on the surface plate 12, the rotation direction with the center O of the fixed surface 12a to the base 13 of the surface plate 12 as the rotation center (FIG. 9). Stiffness is high in the direction indicated by the arrow a). However, the rigidity of the fixed surface 12a in FIG. 9 in the X-axis and Y-axis directions, that is, in the lateral direction is low, so that the surface plate 12 rolls and there is a possibility that the center O is shifted although it is minute.

In the second embodiment, the surface plate 12 and the base 13 are connected at the center position of the fixed surface to the base 13 of the surface plate 12 (the center of the surface plate 12) so that the roll of the fixed surface 12a can be absorbed, for example, A support body 41 made of a flexible material was provided. In other words, the acceleration / deceleration load in the X-axis and Y-axis directions of the fixed surface 12a applied to the stage 11 on the surface plate 12 without hindering deformation due to thermal expansion of the surface plate 12 (for example, in the arrow a in FIG. 10). The lateral load) G, particularly a rapid acceleration / deceleration load, is received by the support 41, and the starting point of thermal deformation of the surface plate 12 is strictly set at the center of the surface plate 12.
According to this, in addition to the effects of the first embodiment, it is possible to eliminate the rolling of the surface plate 12 and the positional deviation of the center O as described above.

In the second embodiment described above, the support body 41 is constituted by a single component, but is not limited to this. For example, as shown in FIG. 11, the support body 41 is divided into two parts, an upper connecting part 41e and a lower connecting part 41f, and both connecting parts 41e and 41f are integrated with a thin disc 41g having flexibility interposed therebetween. It may be the configuration.
If the support body 41 is configured in this manner, the height dimension (the dimension in the vertical direction in the figure) can be given a slight degree of freedom by bending in the direction intersecting the plate surface of the thin disk 41g. Therefore, in FIG. 6, it is possible to provide a margin for setting the height dimension of the support body 41 with respect to the height dimension of the attachment 14 and adjusting the height when the support body 41 is bolted to the surface plate 12 and the base 13. .
The acceleration / deceleration load G in the X-axis and Y-axis directions of the fixed surface 12a (see, for example, the arrow a in FIG. 10) is received by the elasticity (deflection) in the direction along the plate surface of the thin disc 41g.
In FIG. 11, the same or corresponding parts as those in FIG. 8 are denoted by the same reference numerals, and the description thereof is omitted.

It is a front view which shows the stage support apparatus with which 1st Embodiment of the surface plate fixing structure by this invention was applied. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1. It is the enlarged view which took out the attachment in FIG. 1 and showed from the open part side. It is explanatory drawing of the effect in the structure of this invention. It is explanatory drawing of a prior art. It is a front view which shows the stage support apparatus with which 2nd Embodiment of the surface plate fixing structure by this invention was applied. FIG. 7 is a cross-sectional view taken along line B-B in FIG. 6. It is sectional drawing which took out and expanded the support body in FIG. It is explanatory drawing of the rigidity in the fixed surface of the surface plate in 1st Embodiment. It is explanatory drawing of the acceleration / deceleration load of the X-axis direction similarly in the fixed surface of a surface plate. It is sectional drawing which shows the other example of the support body in 2nd Embodiment.

Explanation of symbols

  11: Stage, 12: Surface plate, 13: Base, 14: Attachment, 15: Bolt (fastener), 41: Support, 41a, 41b: Mounting base, 41c: Cylindrical connecting part, 41d: Through hole, 41e, 41f: connecting portions.

Claims (4)

A surface plate fixing structure that fixes a surface plate that supports the positioning stage so as to be movable to the base,
The surface plate is equidistant from the center of the surface fixed to the base of the surface plate, and the plurality of attachments are positioned respectively at a plurality of positions spaced at equal angular intervals with the center as the rotation center. Fixed to the base,
Each attachment is configured to have a rigidity in a direction along a straight line connecting the position and the center of the fixed surface of the surface plate is lower than the rigidity of the surface plate ,
Fixation between the plate and the base of each attachment are fastened by fasteners, each attachment plate fixed structure, characterized in Rukoto opening portion is formed for the fastening operation of the fastener .   Each attachment has higher rigidity in the direction along the rotation direction with the center of the fixed surface of the surface plate as the center of rotation than the rigidity in the direction along the straight line connecting the position of the attachment and the center of the fixed surface of the surface plate. 2. The surface plate fixing structure according to claim 1, wherein the surface plate fixing structure is configured to have rigidity. A support that connects the surface plate and the base at the center position of the fixed surface to the base of the surface plate and absorbs relative shaking in the X-axis and Y-axis directions of the fixed surface between the surface plate and the base. The surface plate fixing structure according to claim 1 , wherein the surface plate fixing structure is provided. The support is divided into two lower connecting portion and the upper connecting portion, two joining portions, a constant according to claim 3, flexible is interposed a disc having, characterized in that formed by integrally Panel fixing structure.

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