JPH0481211B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is carried out, for example, to align a wafer with a pattern mask in an exposure step of a semiconductor manufacturing process. This relates to a positioning table used for positioning a wafer, etc.

Conventional technology In a positioning table, X and Y that are orthogonal to each other
Axis and rotation: It is common to use two linear tables and one rotary table stacked on top of each other for the shaft, but this method uses three stacked tables, which increases the height of the device and makes it more compact. It has the drawback that it is difficult to design the same, and the rigidity in the vertical direction is also low.

In order to improve this problem, a table having a one-stage structure as shown in Japanese Patent Laid-Open No. 59-72727 has been proposed. FIG. 2 shows a conventional positioning table shown in Japanese Unexamined Patent Publication No. 59-72727.

In FIG. 2, 1 is a base plate and 2 is an upper table on which the position is positioned. There is a group of balls 3 arranged on the circumference between the base plate 1 and the upper table 2, and together with the weight of the upper table 2, the upper table 2 is regulated on one plane on the base 1. .
The upper table 2 is provided with rollers 4a, 4b, and 4c. The base 1 has motors 5a, 5b, 5
c is attached, and these motors 5a, 5
Blocks 7a, 7b, 7c are connected to guides 8a, 8 by screws 6a, 6b, 6c driven by screws 6a, 5c.
b, move along 8c. Spring 9a, 9b, 9
c acts on the upper table 2 and screws 6a, 6b, 6
Rollers 4a, 4b, 4c are pressed against blocks 7a, 7b, 7c in the axial direction of c.

When the motors 5a, 5b, and 5c are driven with the above configuration, the upper table 2 moves in the X, Y, and ⓓ directions.

However, this conventional example has the following drawbacks.

First, the rollers 4a, 4b, 4c are connected to the screws 6a, 6
In order to move in the axial direction of screws 6a, 6b,
The accuracy of 6c directly appears as the positioning accuracy of the table, and the positioning accuracy of the upper table 2 cannot be increased more than the machining accuracy of the screws 6a, 6b, and 6c.

In addition, the force acting on the upper table 2 is directly applied to the screw 6.
Since it acts in the axial direction of a, 6b, and 6c, especially when a high-precision ball screw is used for the screw,
Since the rigidity of the nut appears as the rigidity of the table, the rigidity of the table in the position regulating direction becomes low.

To solve the above-mentioned problems, a stage positioning device of a type in which a trapezoidal cam is driven by a friction wheel as shown in FIG. 5 has been proposed in Japanese Patent Laid-Open No. 178728/1983.

In Fig. 5, 51 is a stage base, 52
is an XY stage, 53 is a trapezoidal cam, 54 is a support wheel, 55 is a rotation support shaft, 56 is a spring, 57
is a roller.

Problems to be Solved by the Invention However, in the conventional example shown in FIG. 5, two trapezoidal cams with two parallel surfaces are located on one side of the table, so the stroke of each trapezoidal cam is large. In addition, the stroke of the table of the XY stage with respect to the predetermined angle of inclination formed by the surface of each trapezoidal cam that contacts the support wheel 54 and the surface that contacts the roller 57 also becomes small, which poses the problem that it is difficult to improve accuracy. Ta.

In view of the above problems, the present invention provides a positioning table with high positioning accuracy and high rigidity in the regulating direction.

Means for Solving the Problems In order to solve the above problems, the positioning table of the present invention includes an upper table having a flat surface, a regulating means for regulating the upper table to move within one plane, and a regulating means provided on the upper table. three rollers, three wedge blocks having contact surfaces that contact the rollers, a spring that biases the upper table to press the rollers against the contact surfaces, and a wedge block that contacts the contact surfaces. The table is provided with a driving means for driving in a direction having a constant inclination, and two of the three contact surfaces, which are parallel to each other, are arranged at positions sandwiching the upper table.

Effects Since the present invention has the above-described configuration and drives the rollers of the upper table via the wedge block,
The accuracy of the drive means is increased by the wedge block, and the positioning accuracy of the table is improved.

Embodiment A positioning table according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of a positioning table according to an embodiment of the present invention, FIG. 3 is a partially sectional plan view, and FIG. 4 is a sectional side view.

The positioning table of this embodiment has a stroke of
Both Y and Y are 2mm, and the feed resolution is about 0.1〓m.

1, 3, and 4, 11 is a base plate, 12 is a lower table, and 13 is an upper table, and the lower table 12 is fixed to the base 11. The upper table 13 has three groups of balls 14a, 1
It is placed on the lower table 12 via 4b and 14c. 3 groups of balls 14a, 14b, 1
4c, balls are kept at appropriate intervals by retainers 15a, 15b, 15c, and 16. However, retainers 15b and 15c are not shown in the figure. Lower table 12 and third group of balls 14a, 1
4b and 14c are regulating means for moving the upper table 13 within one plane.

In this example, since three sets of units of the same shape are included, the parts common to each unit are subscripted a, b, c.
Shown with .

There are brackets 17 in three places on the upper table 13.
a, 17b, 17c and pins 18a, 18b, 18
Rollers 19a, 19b, and 19c are attached by c. Here, rollers 19a, 19b, 19
c is rotatably attached around pins 18a, 18b, and 18c.

On the other hand, a guide block 20 is mounted on the base plate 11.
a, 20b, 20c are fixed, and the slide guide 2 is fixed to these guide blocks 20a, 20b, 20c.
Wedge block 2 via 1a, 21b, 21c
2a, 22b, and 22c are slidably attached. Ball screws 24a, 24b, 24c and pulse motors 25a, 25b, 25c constituting means 23a, 23b, 23c for driving wedge blocks 22a, 22b, 22c are connected to connectors 26a, 25c.
The shafts are fixed to each other by 6b and 26c. Ball screws 24a, 24b, 24c are bearings 27
a, 27b, 27c (27b and 27c are omitted from the diagram)
The pulse motors 25a, 25b, 25c are also attached to the guide blocks 20a, 20b, 20c via brackets 29a, 29b, 29c. . Furthermore, the ball screw nuts 30a, 30b,
30c is wedge block 22a, 22b, 22c
are fixed respectively.

With this configuration, the pulse motors 25a, 25b,
When 25c is driven, wedge blocks 22a, 22
b, 22c move in the axial direction of the ballges 24a, 24b, 24c. In addition, wedge block 22
a, 22b, 22c are rollers 19a, 19b, 1
Contact surfaces 31a, 31 which are planes that contact with 9c
b, 31c. This contact surface 31a, 3
1b, 31c are ball screws 24a, 24b, 24
It is inclined at a constant angle 〓 with respect to the rotation axis of c.

On the other hand, there are brackets 32, 3 on the upper table 13.
3, 34, 35 and spring holder pins 36, 37, 3
8 and 39 are provided, and spring bracket pins 40, 41, 42, and 43 are fixed to the base plate 11.
A tension spring 44 is installed between the spring holder pins 36 and 40.
However, a tension spring 45 is tensioned between the spring bracket pins 37 and 41, a tension spring 46 is tensioned between the spring bracket pins 38 and 42, and a tension spring 47 is tensioned between the spring bracket pins 39 and 43.
The wedge block 22 is held by the tension springs 45 and 47.
The roller 19b is attached to the tension spring 4 on the contact surface 31a of the
4, the contact surface 31b of the wedge block 22b
At the same time, the rollers 19c are pressed by the tension springs 46 against the contact surfaces 31c of the wedge blocks 22c.

Here, the wedge blocks 22a, 22b, 22c
As shown in FIG.
The abutting surfaces 31b and 31c of the wedge blocks 22b and 22c are set at right angles, and the abutting surfaces 31b of the wedge block 22b and the abutting surfaces 31c of the wedge block 22c are parallel to each other and are positioned to sandwich the upper table 13. Also, at this time, the positions of rollers 19b and 19c are
A perpendicular line D that passes through the center of the roller 19b and drops to the contact surface 31b, and a perpendicular line D that passes through the center of the roller 19c and drops to the contact surface 31c.
The distance is determined to be L (L>O) from the perpendicular line E drawn to .

Now, the direction parallel to the contact surface 31a is x, the direction perpendicular to it is y, and the angle between the contact surface 31a and the rotation axis of the ball screw 24a is, for example, = sin ^-1 (1/20), and the ball screw The lead of 24a is 2mm.
When the pulse motor 25a is driven to turn the ball screw 24a by 1/1000 rotation, the wedge block 22a moves 2〓m and the roller 19a moves 0.1〓m in the Y direction.

The rollers 19b and 19c are also similar to 19a, and the principle of positioning the upper table 13 in the x, y, and downward directions by positioning the rollers 19a, 19b, and 19c is described in Japanese Patent Laid-Open No. 59-
Since the content is well known as disclosed in Japanese Patent No. 72727, it will be omitted here.

As described above, in this embodiment, the pulse motor 25
By controlling a, 25b, and 25c, the upper table 13 can be positioned in the x, y, and downward directions.
At this time, the wedge blocks 22a, 22b, 22c
The lead error of the ball screws 24a, 24b, 24c that drive the wedge blocks 22a, 22
With respect to the angle formed by the contact surfaces 31a, 31b, 31c of b, 22c and the axes of the ball screws 24a, 24b, 24c, the positioning error of the rollers 19a, 19b, 19c appears small as 〓=〓・sin〓 . For this reason, the upper table 13
The final positioning accuracy becomes higher.

Further, rollers 19a, 19b, 19c are connected to pulse motors 25a, 25b, 25c and ball screw 24 via wedge blocks 22a, 22b, 22c.
a, 24b, and 24c, the external force acting on the upper table 13 is applied to the wedge block 2.
2a, 22b, 22c, and the nuts 30a, 30 of the ball screws 24a, 24b, 24c.
It does not directly add to b and 30c. Therefore, the nuts 30a, 30 of the ball screws 24a, 24b, 24c
The rigidity of the upper table 13 in the regulating direction can be made greater than that of b and 30c.

Further, since the contact surfaces 31b and 31c, which are parallel to each other, are positioned to sandwich the upper table 13, the wedge blocks 22b and 22c can have a large stroke, resulting in high accuracy and reliability.

In addition, ball screws 24a, 24b, 2 are used as drive means.
4c and pulse motors 25a, 25b, and 25c, the configuration of the device is simple and easy to handle, and a highly accurate positioning table can be realized.

Effects of the Invention As described above, the present invention includes an upper table having a flat surface, a regulating means for regulating the upper table to move within one plane, three rollers provided on the upper table, and the rollers. It consists of a wedge block that comes into contact with the roller, and a drive means that drives the wedge block in a direction that has a certain angle to the surface that comes into contact with the roller.The wedge block increases the accuracy and rigidity of the drive means. This provides a positioning table with high precision and rigidity.

In addition, by arranging the wedge block so that the two mutually parallel contact surfaces sandwich the upper table, the moving stroke of the wedge block can be made longer, resulting in a highly accurate and reliable positioning table. can be provided.

In addition, as a drive means for the wedge block, a ball screw and a pulse motor having an axial direction inclined to the contact surface of the wedge block with the roller are used, so it is possible to provide a positioning table with high precision and easy handling. .

[Brief explanation of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention, FIG. 2 is a partially cutaway perspective view of a conventional example, FIG. 3 is a partially sectional plan view of an embodiment of the present invention, and FIG. 4 is a perspective view of an embodiment of the present invention. FIG. 5 is a cross-sectional side view of one embodiment of the present invention, and FIG. 5 is a plan view of a conventional trapezoidal cam drive type stage positioning device. 11...Base board, 12...Lower table, 13
...Upper table, 14a, 14b, 14c...Ball group, 15a, 15b, 15c, 16...Retainer, 19a, 19b, 19c...Roller, 22
a, 22b, 22c...wedge block, 23
a, 23b, 23c...driving means, 24a, 24
b, 24c...Ball screw, 25a, 25b, 2
5c...Pulse motor, 31a, 31b, 31c
...Contact surface, 44, 45, 46, 47...Tension spring.

Claims (1)

[Claims] 1. An upper table having a flat surface, a regulating means for regulating the upper table to move within one plane, three rollers rotatably provided on the upper table, and the rollers. three wedge blocks, each having a contact surface that comes into contact with the roller, and a spring that biases the roller to press the roller against the contact surface;
a driving means for driving the wedge block in a direction having a constant inclination with respect to the abutment surface, and two of the three abutment surfaces of one set are parallel to each other and A positioning table characterized in that the wedge blocks are arranged so as to sandwich the table, and the two faces of another combination are arranged at right angles to each other. 2. Positioning according to claim 1, characterized in that a ball screw having an axial direction in a direction inclined to the contact surface and a pulse motor for driving the ball screw are used as driving means for the wedge block. table.