JP2002349717A - Positioning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positioning device that can reconcile lightness and high precision positioning by ensuring precise positioning irrespective of deformation of a casing. SOLUTION: The positioning device 10, in which a process chamber P in communication with the outside via an opening 20a cut in the casing 20 is sealed off by a differential evacuation seal 60, has a first table 41 disposed in the process chamber P, a first moving part 40 connected to the first table 41 via the opening 20a to move the first table 41 from outside the casing 20, and an intermediate member 30 disposed between the casing 20 and the first moving part 40. The differential evacuation seal 60 forms a seal between the intermediate member 30 and the first moving part 40, and an O-ring 21 for absorbing deformation of the casing 20 forms a seal between the intermediate member 30 and the casing 20. Even if the casing 20 deforms, the O-ring 21 can absorb the deformation while maintaining the sealing state, so that the use as a reference plane of a surface of, for example, a surface plate A outside the casing 20 can ensure precise positioning.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positioning device capable of moving a work in a room isolated from an external environment, for example.

[0002]

2. Description of the Related Art In a semiconductor manufacturing apparatus and the like, a workpiece is mounted on a stage and moved in a process chamber maintained in a vacuum or special gas atmosphere for processing. Here, if a positioning device is provided in the process chamber, there is a possibility that lubricant or the like supplied to the movable portion may scatter and contaminate the process chamber.

In order to solve such a problem, for example, US Pat. No. 4,191,385 discloses an integrated negative pressure sealed gas bearing assembly. In such prior art,
By providing a movable part movable in a two-dimensional direction on the bearing block, forming a process chamber between the bearing block and the movable part, and sealing the process chamber and the outside with a differential exhaust seal, A workpiece placed on a movable part can be processed therein while maintaining a negative pressure environment. Therefore, the drive unit for driving the work can be installed outside the process chamber, whereby contamination of the process chamber can be suppressed, and maintenance of the drive unit can be easily performed.

[0004]

By the way, the processing in such a process chamber is performed by a process such as semiconductor manufacturing.
It is applied to work requiring extremely high precision. Here, it is also conceivable that the surface serving as the processing reference is the inner surface of the housing. However, for example, when the process chamber is evacuated, a large force is applied to the casing that covers the process chamber based on a pressure difference between the inside and the outside of the casing, so that a small deformation occurs. Specifically, even in a case having a wall thickness of 30 mm, if the inside is maintained at a high vacuum, there is a possibility that a deflection of about several hundred μm may occur at the center of each surface. In particular, when the volume of the housing is increased in response to the increase in the size of the work, the area of each surface also increases, so that the deformation becomes more remarkable. In such a case, if the surface serving as the processing reference is the inner surface of the housing, the processing reference position changes, and there is a possibility that accurate processing cannot be performed. For such a problem, there is an idea that deformation is suppressed by increasing the wall thickness of the housing. However, increasing the wall thickness introduces a new problem that the entire device becomes heavier.

In view of the above-mentioned problems of the prior art, the present invention provides a positioning device that achieves accurate positioning regardless of the deformation of the housing, that is, achieves both weight reduction and high-precision positioning. With the goal.

[0006]

In order to achieve the above-mentioned object, a positioning apparatus according to the present invention is configured such that a process chamber communicating with the outside through an opening provided in a housing is sealed with a differential exhaust seal. In the positioning device, a first table disposed in the process chamber, a first moving unit connected to the first table via the opening, and moving the first table from outside the housing. An intermediate member disposed between the housing and the first moving unit, wherein the space between the intermediate member and the first moving unit is sealed by the differential exhaust seal. The space between the intermediate member and the housing is sealed by deformation absorbing means for absorbing deformation of the housing.

[0007]

According to the positioning apparatus of the present invention, in the positioning apparatus in which the process chamber communicating with the outside via the opening provided in the housing is sealed with the differential exhaust seal, the first chamber disposed in the process chamber. A table, a first moving unit connected to the first table via the opening, and moving the first table from outside of the housing; and a first moving unit configured to move the first table from the outside of the housing. An intermediate member disposed therebetween, and the space between the intermediate member and the first moving unit is sealed by the differential exhaust seal, and the space between the intermediate member and the housing is provided. Since the casing is sealed by deformation absorbing means for absorbing the deformation of the casing, even if the casing is deformed, the deformation absorbing means can absorb the deformation while maintaining the sealed state. Table of surface plate etc. outside the housing The With reference plane, can be achieved accurate positioning.

Further, it is preferable that the deformation absorbing means is at least one of an O-ring and a bellows, but is not limited to this.

[0009] On the first table, a second table and a second moving section for moving the second table in a direction intersecting with the moving direction of the first moving section are arranged. It is preferable that the moving distance of the first moving unit is larger than the moving distance of the second moving unit, because the moving to any position in the two-dimensional direction can be performed. The magnitude of the “moving distance” here does not always correspond to the magnitude of the movable range (stroke) of each table, but refers to the magnitude of the traveling distance determined by the use conditions of the positioning device.

[0010] Further, it is preferable that two openings are formed, and each first moving portion is connected to the first table by a support rod extending through the two openings.

Here, the differential exhaust seal means, for example, by exhausting a gas in a minute gap between two opposing surfaces so that, in a non-contact state, the atmosphere on both sides sandwiching the opposing surfaces (for example, atmospheric pressure and atmospheric pressure). (High vacuum). In the embodiment described below, a member having an exhaust surface is referred to as a differential exhaust seal.

[0012]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a front cross-sectional view of a positioning device according to a first embodiment of the present invention, and FIG. 2 is a side cross-sectional view of the positioning device of FIG. 1 as viewed in the direction of arrows II-II. FIG. 3 is a view of a part of the positioning device of FIG. 1 as viewed in the direction of arrows III-III. In addition, FIG.
In FIG. 2, the upper part of the sealed housing is omitted.

As shown in FIG. 1, a positioning device 10 according to the present embodiment includes a housing 20 having a process chamber P, an intermediate member 30 disposed below the housing 20, and an internal member 30 disposed inside the housing 20. A first table 41 is provided, and a first moving unit 40 that supports the first table 41 from outside the housing 20.

The substantially rectangular parallelepiped housing 20 supported on the base A by the support legs 20b (FIG. 2) has an elongated hole-shaped opening 20a formed in the lower wall 20c. In FIG. 1, a groove 20d is formed on the lower surface of the lower wall 20c of the housing 20 along and near the periphery of the opening 20a, and an O-ring as a deformation absorbing means is formed in the groove 20d. 21 are arranged. The O-ring 21 has an upper surface 31 at the top 31 of the intermediate member 30 facing the lower surface of the lower wall 20 c of the housing 20.
a, and are sealed between them.

The intermediate member 30 is formed from a top portion 31 and side portions 32. The pair of side portions 32 are erected on the surface plate A, and the intermediate member 30 is formed by using bolts 50 each of which is inserted into a counterbore hole 32a penetrating each side portion 32 vertically in FIG. It is attached to surface plate A. The top 31 has an opening 31 having the same shape as the opening 20a of the housing 20 at the center thereof.
and a differential exhaust seal 60 is formed on the lower surface 31c. The differential exhaust seal 60 has grooves 61, 62,
66, communication holes 63 and 64, and an exhaust hole 65.

In FIG. 3, an opening 31b of the intermediate member 30 is provided.
Along the periphery of the three, three grooves 61, 62, 66 extend. Six communication holes 63 and 64 are respectively formed from the groove bottoms of the grooves 61 and 62 toward the inside of the intermediate member 30, and four exhaust holes extending horizontally inside the intermediate member 30 as shown in FIG. 2. It communicates with the hole 65. As shown by the dotted line in FIG. 3, both ends of the exhaust hole 65 are drawn out of the intermediate member 30, and each is connected to a suction pump (not shown). The groove 66 also extends in the longitudinal direction from the boundary between the arc portion and the linear portion, reaches both ends of the intermediate member 30, and communicates with the atmosphere.

An opening 20a of the housing 20 and an opening 31b of the intermediate member 30 have a first table 41,
The support bar 43 connecting the second and third members extends. The moving block 42 is supported by a bearing 45 movable along a guide rail 44 installed on the surface plate A. A ball screw nut portion 42a fixed to the lower surface of the moving block 42 has a ball screw nut 42a. The screw shaft 46 of the screw is engaged via a number of balls (not shown) circulating in the nut portion 42a. The screw shaft 46 is connected to a rotation shaft of a motor 47 mounted on the surface plate A via a coupling 46a. Guide rail 44, bearing 45, and bearing 4
5, a linear guide is formed by a number of rolling elements (not shown) that circulate between the guide rail 44 and the bearing 45. By being supported by the linear guide, the upper surface of the moving block 42 and the lower surface of the top 31 of the intermediate member 30 are opposed to each other via a small clearance. The moving block 42, the linear guide, the ball screw, and the motor 47 constitute a first moving unit 40.

Next, the positioning device 1 according to this embodiment
The operation of 0 will be described. When the motor 47 is driven,
The screw shaft 46 rotates, and the ball screw nut portion 42a screwed with the screw shaft 46 converts the rotational motion into an axial motion. The moving block 42 is a linear guide (44, 45).
, And moves in accordance with the rotation of the screw shaft 46, so that the first table 41 also moves in the same direction.

Here, when the inside of the housing 20 is in a vacuum, the pressure difference between the inside and the outside of the housing 20 becomes large, and the housing 20 is minutely deformed accordingly. More specifically, the opening 20
Since the rigidity is lowest in the vicinity of the opening 20a in FIGS.
Is deformed to push upward. Here, in the present embodiment, even if the lower surface of the housing 20 moves upward due to deformation, the O-ring 21 as the deformation absorbing means does not separate from the upper surface of the intermediate member 30 and The hermeticity of 20 is maintained. That is, the amount of deformation of the casing 20 is anticipated in advance, and the O-ring 21 is always attached to the casing 20 and the intermediate member 3.
0 is set so as to maintain a state of being in close contact with both of them. That is, as the pressure in the process chamber P is reduced and the lower surface 20C of the housing 20 is displaced upward due to bending, the amount of elastic deformation (crush allowance) of the O-ring 21 decreases, but the assumed maximum displacement amount O-ring 21
The elastic deformation is not completely eliminated.

Since the housing 20 is not directly connected to the intermediate member 30, the intermediate member 30 and the moving block 42 are not connected.
Is designed to have high rigidity,
Even if the housing 20 is deformed, the influence does not reach the intermediate member 30. Therefore, the lower surface 31b of the top 31 of the intermediate member 30
Since the distance between the upper surface of the moving block 42 and the upper surface of the moving block 42 is maintained in the initial state, air and the like are prevented from flowing into the process chamber from the gap between the upper surface of the moving block 42 and the lower surface of the intermediate block 30 from the atmospheric pressure side. Influence on the function of the dynamic exhaust seal 60 is suppressed.

On the other hand, the positioning of the first table 41 depends on the positioning accuracy of the moving block 42 with respect to the surface plate A.
The surface plate A is high-precision and strong, and the upper surface thereof is used as a reference surface, and a first moving section 40 for moving the first table 41 is assembled on the surface, thereby easily providing a high-precision positioning device. Can be obtained. That is, by assembling the moving section 40 with reference to the upper surface of the surface plate A, a high-precision guide mechanism can be easily configured, so that a small clearance between the upper surface of the moving block 42 and the lower surface 31c of the top portion 31 of the intermediate member 30. Can be maintained at a predetermined value with high precision, and a high-performance differential exhaust seal can be obtained. That is, the first table 4
Even if the housing 20 is deformed, the position 1 is always determined by the high accuracy of the surface plate A regardless of the deformation, so that accurate positioning can be maintained. still,
The first table 41 may be provided with a uniaxial table device capable of supporting a work intersecting with the moving direction of the first table 41. The moving block 42 may be driven using, for example, a linear motor or using a belt and a pulley.

FIG. 4 is a side sectional view of a positioning device 110 according to a second embodiment of the present invention. FIG.
FIG. 5 is a top view showing the configuration of FIG. 4 in a state cut along a horizontal plane including a VV line. In FIG. 4, a pair of components having substantially the same configuration as those corresponding to the intermediate member, the moving block, and the guide mechanism (two sets of linear guides) of the moving block in FIGS. 1 and 2 are provided. Now, only the differences will be described.

In FIG. 4, two moving blocks 242 are provided.
The upper end of the connecting portion 243 fixed to the upper portion has a single first
A table 141 is attached. Table 141
On the top, a pair of guide rails 144 is installed,
A bearing 145 movable along a plurality of rolling elements (not shown) along the guide rail 144 supports the second table 241. A screw shaft 146 of a ball screw is engaged with a ball screw nut portion 241a fixed to the lower surface of the second table 241 via a number of balls (not shown). The screw shaft 146 is connected to the rotation shaft of the motor 147 mounted on the first table 141 and the coupling 14.
6a. The guide rail 144, the bearing 145, and a number of rolling elements form a linear guide, and the linear guide, the ball screw, and the motor 147 form a second moving unit 140. First table 141,
The second table 241 and the second moving unit 140 are
0 is covered. Considering that the inside of the housing 120 is made to be in a vacuum state, the lubricant used in the second moving unit 140 should be of a type in which the scattering of lubricating oil using vacuum grease or solid lubricant is small. Is preferred. Nevertheless, it is difficult to eliminate the scattering of lubricant at all,
It is preferable that the moving distance of the moving unit 140 is set to be smaller than the moving distance of the first moving unit 240.
The magnitude of the “moving distance” here does not refer to the magnitude of the movable range (stroke) of each moving unit, but the magnitude of the traveling distance when actually used as a positioning device. Therefore, it is not always the case that the shorter moving stroke is selected as the second moving unit 140. Even if the stroke is short, if the positioning device 110 is used under the condition that the moving distance converted per unit time, that is, the moving distance is larger in the second moving part than in the first moving part, the second moving This is because it is inappropriate as a unit, and in such a case, the shorter stroke is selected as the first moving unit. As the motor 147, for example, a rotary ultrasonic motor or the like is suitable for use in a vacuum in addition to a normal rotary motor, and this may be used.
Further, although a combination of a ball screw and a motor is used for moving the second table 241, for example, a linear motor (an electromagnetic type or an ultrasonic motor) may be used instead.

In the moving section 240 shown in FIG. 5, the moving block 2 is located below the pair of intermediate members 30 (on the back side of the paper).
42 are respectively provided by the linear guide shown in FIG.
The end (the upper part in FIG. 5) of the moving block 242 is connected to the connecting member 242c.
Are connected to each other. A ball screw nut 242a is attached to the connecting member 242c, and a screw shaft 246 of the ball screw is screwed to this via a number of balls. The screw shaft 246 is supported by the support portions 246b, 24
6c is attached on the surface plate A (FIG. 4), and one end thereof is connected to the bracket 2 via a coupling 246a.
It is connected to the rotating shaft of a motor 247 fixed to 47a.

According to the present embodiment, in addition to the operation and effects of the positioning device 110 described above, the first table 141
The first table 240 is moved in the X direction (the direction perpendicular to the plane of FIG. 4) by the first moving unit 240 of the positioning device 110, and the second table 241 is moved by the second moving unit 140 arranged on the first table 141. Is moved in the Y direction (the horizontal direction in FIG. 4) orthogonal to the X direction. By placing the work on the second table 241, the work can be accurately moved in any two-dimensional direction. Becomes possible. In the present embodiment, the intermediate member 30, the moving block 242, and the like are provided in pairs, but instead, a single wide intermediate member and a moving block may be used.
In this case, two openings and a differential exhaust seal are provided in the intermediate member, and two connecting portions are fixed to the moving block. An O-ring is also provided to surround each opening. Since the facing area between the intermediate member and the housing increases,
In order to reliably maintain the hermetic seal between the two O-rings, it is preferable to increase the clearance between the intermediate member and the housing between the two O-rings.

FIG. 6 is a partially omitted side sectional view of the positioning device according to the third embodiment. A positioning device 10 ′ shown in FIG. 6 is a positioning device 10 ′ according to the first embodiment.
Has a bellows mechanism in place of the O-ring. More specifically, a mounting plate 221 having an opening 221a through which the support bar 43 is inserted is fixed by a bolt 222 inside the opening 20a 'of the housing 20'.
On the mounting plate 221 and the upper surface 31a of the intermediate member 30,
Both ends of a metal bellows 223 as a deformation absorbing means are hermetically connected.

Since the metal bellows 223 has an expandable and contractible structure, even when the casing 20 'is deformed so as to push up the opening 20a' when the inside of the casing 20 'is evacuated, the bellows is used. The extension of 223 prevents the influence of the deformation from being transmitted to the intermediate member 30. Other configurations are the same as those of the embodiment shown in FIGS. In the third embodiment, the case where the O-ring of the positioning device 10 is replaced with a bellows mechanism has been described. However, it is needless to say that the same applies to the second embodiment and the following fourth embodiment. It is possible.

FIG. 7 is a partially omitted cross-sectional view according to the fourth embodiment. Positioning device 310 of the present embodiment
A housing 320 having a process chamber P, an intermediate member 330 arranged on the side of the housing 320, a drive shaft 343 arranged to be able to be taken in and out of the housing 320 and supporting a table (not shown); And a first moving unit 340 supported from the outside of the housing 320. The drive shaft 343
May be penetrated on both sides of the housing 320, and a structure for supporting the moving block 342 such as the moving block 342 and the intermediate member 330 may be provided and supported on the opposite side.

A rectangular opening 320a extending in a direction perpendicular to the plane of the drawing is formed in the side wall 320c of the rectangular parallelepiped housing 320 supported on the platen A by the support legs 320b.
A groove 320d is formed on the side surface 320c of the housing 320 along and around the periphery of the opening 320a, and an O-ring 321 as a deformation absorbing means is arranged in the groove 320d. . The O-ring 321 abuts on a surface of the side wall 331 of the intermediate member 330 facing the side surface 320c of the housing 320, facing the side surface 320c of the housing 320, and seals the gap between the surfaces.

The intermediate member 330 is formed by a side wall 331 and a peripheral wall 332 connected to the outer periphery thereof, and is fixedly attached to a support member 333 provided on the surface plate A. In the peripheral wall 332, a substantially rectangular parallelepiped drive shaft 34 is provided at the center.
A moving block 342 having an opening through which the reference numeral 3 is inserted is arranged. A moving block 342 that forms a part of the first moving unit 340 includes a hydrostatic bearing 342a and a differential exhaust seal 342b on an inner peripheral surface of the opening facing the drive shaft 343.
(Comprising an annular groove, an exhaust path communicating with the annular groove, and a suction pump (not shown)). Also, the intermediate member 330
In the side wall 331, on a surface facing the moving block 342, an opening having the same shape as the static pressure bearing 331a and the opening 320a, and a differential exhaust seal 331b (first to third) formed to surround the opening. In addition, a static pressure bearing 332a is provided on the inner peripheral surface of the peripheral wall 332 facing the moving block 342. Further, the moving block 3 is also provided on the support member 333.
A static pressure bearing 333a is provided on the surface facing the surface.
Therefore, the moving block 342 applies the hydrostatic bearings 331a, 332a, and 33 to the intermediate member 330 and the support member 333.
It is supported in a non-contact manner by 3a, and is slidable in a direction perpendicular to the plane of FIG.

The operation of the positioning device 310 according to the present embodiment will be described.
The drive shaft 34 is driven by a motor provided on the table 341.
Reference numeral 3 denotes a moving block 342 in the left-right direction (X direction) in FIG.
, And can move integrally with the moving block 342 in a direction perpendicular to the paper surface (Y direction).

Here, when the inside of the housing 320 is in a vacuum, the pressure difference between the inside and the outside of the housing 320 becomes large, and the housing 320 is slightly deformed accordingly. More specifically, since the rigidity is the lowest near the opening 320a, the opening 3 in FIG.
20a is deformed so as to be pushed rightward. Here, in the present embodiment, even if the side wall 320c of the housing 320 moves rightward due to deformation, the O-ring 321 as the deformation absorbing means does not separate from the right side surface of the intermediate member 330. In addition, the hermeticity of the housing 320 is maintained.

Further, since the housing 320 is not directly connected to the intermediate member 330, even if the housing 320 is deformed, the influence is not exerted on the intermediate member 330. Therefore, the intermediate member 3
Since the distance between the side wall 331 of the moving block 30 and the opposing surface of the moving block 342 is maintained in the initial state, the hydrostatic bearing 331a,
Influence on the functions of 332a, 333a and differential exhaust seal 331b is suppressed.

Although the present invention has been described with reference to the embodiments, it should be understood that the present invention should not be construed as being limited to the above embodiments, and that modifications and improvements can be made as appropriate. is there. For example, the groove 6 of the differential exhaust seal 60
1 and 62 are arranged in two rows, but are not limited thereto, and may be arranged in one row or three or more rows according to the performance of the suction pump, the magnitude of the differential pressure inside and outside the process chamber, and the like. Also, the size of the gap between the intermediate member 30 or the like as the exhaust surface and the moving block 42 or the like as the opposing seal surface is determined in consideration of the performance of the suction pump and the like, and can be appropriately selected from several μm to several hundred μm. It is. Further, the bearing is not limited to the linear guide (44, 45), and various types of bearings such as a hydrostatic bearing and a rolling bearing can be used. Further, the groove 20d for positioning such as the O-ring 21 is provided on the housing side, but it may be provided on the intermediate member side or both.

[0035]

According to the positioning apparatus of the present invention, in the positioning apparatus in which the process chamber communicating with the outside through the opening provided in the housing is sealed with the differential exhaust seal, the process chamber is disposed in the process chamber. A first table, the first table
Connected to the table via the opening;
A first moving unit that moves the table from outside the housing, and an intermediate member disposed between the housing and the first moving unit, wherein the intermediate member and the first The moving part is sealed by the differential exhaust seal, and the intermediate member and the housing are sealed by deformation absorbing means for absorbing deformation of the housing. Even if the body is deformed, the deformation absorbing means can absorb the deformation while maintaining a sealed state. For example, by using a surface such as a surface plate outside the housing as a reference plane, accurate positioning can be achieved. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a positioning device according to a first embodiment of the present invention.

FIG. 2 is a side cross-sectional view of the positioning device of FIG. 1 as viewed in the direction of arrows II-II.

FIG. 3 is a view of a part of the positioning device of FIG. 1 as viewed in the direction of arrows III-III.

FIG. 4 is a side sectional view of a positioning device according to a second embodiment of the present invention.

FIG. 5 is a top view showing the configuration of FIG. 4 cut along a horizontal plane including a VV line.

FIG. 6 is a partially omitted side view of a positioning device according to a third embodiment of the present invention.

FIG. 7 is a partially omitted side view of a positioning device according to a fourth embodiment of the present invention.

[Explanation of symbols]

 10, 10 'Positioning device 20, 20', 120, 320 Case 30 Intermediate member 40, 240, 340 First moving unit 41, 141 First table 241 Second table 140 Second moving unit 60, 331b, 342b Differential exhaust seal

Continued on front page F term (reference) 2F078 CA01 CA08 CB13 3J042 AA02 BA03 CA08 CA17 3J102 AA02 BA05 BA12 CA11 CA32 EA02 EA24 GA07 5F046 CC01 CC03 CC17

Claims (4)

[Claims] 1. A positioning device in which a process chamber communicating with the outside via an opening provided in a housing is sealed with a differential exhaust seal, wherein: a first table arranged in the process chamber; Connected through the opening to
First moving the first table from outside the housing;
A moving member, and an intermediate member disposed between the housing and the first moving portion, wherein the differential exhaust seal is provided between the intermediate member and the first moving portion. And a space between the intermediate member and the housing is sealed by deformation absorbing means for absorbing deformation of the housing. 2. The positioning device according to claim 1, wherein said deformation absorbing means is at least one of an O-ring and a bellows. 3. A second table and a second moving unit for moving the second table in a direction intersecting with a moving direction of the first moving unit are arranged on the first table, The positioning device according to claim 1, wherein a moving distance of the first moving unit is larger than a moving distance of the second moving unit. 4. The apparatus according to claim 1, wherein two openings are formed, and each of the first moving parts is connected to the first table by a support bar extending through the two openings.
The positioning device according to any one of claims 1 to 3.