JPH03293586A - Positioning table apparatus - Google Patents

Abstract

PURPOSE:To simplify, lighten and miniaturize a structure, to enhance positioning accuracy and to make the use in a vacuum chamber possible by incorporating a linear motor to directly drive a work table. CONSTITUTION:N-poles and S-poles are alternately arranged on a base table 1 composed of a magnetic material in parallel to X- and Y-axes and a group of permanent magnets 2 is arranged in a gridiron pattern. The first sliders 4 having coil elements 4a provided to the surfaces thereof opposed to the group of the permanent magnets 2 are provided on a pair of the first linear guide shafts 3 parallel to the X-axis provided on both sides of the table 1. The second sliders 7 having coil elements 7a provided to the surface thereof opposed to the group of the permanent magnets 2 are provided on the second linear guide shaft 5 supported by the guide shafts 3 so as to cross the shafts 3 at a right angle and a work mounting table 6 is provided on the slider 7. The elements 4a, 7a are used as armature coils and the magnets 2 are used as field magnets to constitute a movable coil type linear DC motor and the supply of a current to the motor is controlled by a controller to which a program is set through the separate driver circuits of the X- and Y-axes.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is applicable to, for example, an exposure 7 assembly apparatus for semiconductor wafers or a machining 2 assembly apparatus.

This invention relates to a Y two-axis positioning table device.

[Conventional technology]

The above-mentioned positioning table device includes a base table, an X-axis table guided by a bearing in the X-axis direction on the base table, and a Y-axis guided by a bearing in the Y-axis direction perpendicular to the Y-axis on the X-axis table. An X-axis table is created by assembling a table and a workpiece mounting table mounted on the Y-axis table one above the other, and using a servo motor and a feed mechanism.

A servo motor-driven X-Y table device is well known in which the Y-axis table is moved in the X-axis and Y-axis directions with respect to the base table and the X-axis table, respectively, and the workpiece mounting table is positioned at a specified position. .

C. Problems to be Solved by the Invention] By the way, the above-described servo motor-driven positioning table device has a drawback such as a sudden movement.

(1) In order to linearly move the table by driving the servo motor, a rotation/linear conversion mechanism such as a feed mechanism is required between the servo motor and the table, so the structure is complicated and Backlash in the screw mechanism also causes a decrease in positioning accuracy.

(2) Since the base table, X-axis table, and Y-axis table are stacked one above the other, the height of the entire table device becomes large, and the load is heavy, requiring a large torque from the servo motor.

(3) As mentioned above, since the number of movable parts in the entire table device increases, errors caused by individual parts accumulate, making it difficult to guarantee high positioning accuracy as a table device.

(4) Since the servo motor protrudes outward from the table, the external dimensions of the entire table device become large.

(5) In addition, especially for linear guide bearings that guide the table, in bearings that have a structure in which needle-like rollers are lined up along the movement path, variations in the dimensional accuracy of the needle-like rollers may cause the table Errors tend to occur in the positioning accuracy of the device.

The present invention has been made in consideration of the above points, and provides a positioning table device that solves the above-mentioned problems by incorporating a linear motor into the table device and directly driving a workpiece mounting table. The purpose is to

[Means to solve the problem]

In order to solve the above problems, the positioning table device of the present invention includes a base table made of a magnetic material, and N poles and S poles arranged alternately in a grid pattern on the base table parallel to the X axis and Y axis. a first linear guide shaft parallel to one of the X and Y axes installed on a base table, and a coil element supported on the guide shaft and facing the permanent magnet group. a first slider, a second linear guide shaft connected to the slider and perpendicular to the first guide shaft; It consists of a second slider equipped with a coil element and a workpiece mounting table mounted on the second slider, and the first slider includes a second slider equipped with a coil element and a workpiece mounting table mounted on the second slider. The workpiece mounting table is positioned at a designated position by controlling the energization of the coil element of the second slider.

In the above configuration, in order to smoothly guide the second guide shaft that moves together with the first slider with a simple mechanism, one end of the second linear guide shaft is connected to the first slider, and the other end is connected to the first slider. can be supported by a magnetically levitated guide bearing installed parallel to the first linear guide shaft.

Furthermore, the first in the above configuration. With respect to the second linear guide shaft, the first. The second sliders can also be guided and supported in a non-contact manner via electromagnetic magnetic levitation bearing mechanisms.

[Function] With the above configuration, a field magnetic field is formed between the permanent magnet group placed on the base table and the slider, from the N pole of the permanent magnet, interlinking with the drive coil of the slider, and returning to the S pole. ing. Therefore, by passing a current through the coil element of the slider, a tMi force is generated between the two, which acts as a thrust force to move the slider along the guide axis.Here, the coil element of the first and second slider By controlling the applied current in accordance with the positioning command, the workpiece mounting table is moved to a specified positioning point on the X-Y coordinates and positioned with high precision. Moreover, since the permanent magnet groups mentioned above are arranged in a two-dimensional grid pattern,
It functions as a field permanent magnet for both Y-axis sliders.

In addition, in a structure in which one end of the second linear guide shaft is connected to the first slider and the other end is supported by a magnetically levitated guide bearing installed parallel to the first linear guide shaft, the magnetically levitated guide Since the second guide shaft is supported in a non-contact manner on the bearing side, it can be guided smoothly without any sliding frictional resistance accompanying movement.

Also, 1st. The structure in which the first and second sliders are guided and supported via electromagnetic magnetic levitation bearing mechanisms with respect to the second linear guide shaft allows the slider to be guided and supported with respect to the guide shaft in a completely non-contact manner. . Moreover, by adopting the magnetic levitation method, it can also be used in a vacuum chamber.

In addition, especially when the environmental conditions are not a vacuum, instead of using a magnetic levitation type bearing, pressurized air is blown from the slider side toward the opposing surface of the slider and the linear guide shaft, so that the slider does not come into contact with the guide shaft. It is also possible to adopt an air bearing that supports the guide in a formula.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

Embodiment 1: In FIGS. 1 and 3, 1 is a base table made of a plate of magnetic material, and the top surface of the table 1 has Y-axis, Y-axis,
Square permanent magnets 2 are arranged and adhered in a grid pattern so that north poles and south poles are arranged alternately parallel to the axis. Also,
For the base table 1, there are Y on both left and right sides.
A pair of first linear guide shafts 3 that are prismatic shafts parallel to the axis.
are attached via a leg stand 3a, and a rectangular cylindrical first slider 4 is guided and supported on each axis of the guide shaft 3. Further, a second linear guide shaft 5 parallel to the Y-axis is connected between the pair of first sliders 4, and a workpiece mounting table 6 is mounted on the upper surface of the guide shaft 5. The second slider 7 that has been moved is guided and supported.

On the other hand, the first slider 4. Coil elements 4a and 7a are arranged on the lower surface side of the second slider 7, and a yoke 4b is arranged on the second slider 7.
, 7b, and constitutes a moving coil type linear DC motor using the coil element as an armature coil and the above-mentioned permanent magnet 2 on the base table side as a field magnet. Note that each of the above-mentioned coil elements 4a and 7a is
As shown in the figure, a controller 8 in which programs such as X-Y axis positioning positions, moving speeds, sequences, etc. are set controls energization through x- and Y-separate driver circuits 9.

In addition, as shown in Fig. 3, the sliders 4 and 7 supported by the linear guide shafts 3 and 5 employ a static pressure guide system that blows out air forced by a blower lO toward the surface facing the guide shafts. With this structure, the slider 4.7 is moved by pressurized air to the guide shaft 3.
．． From 5 onwards, the floating guide is provided in a non-contact manner.

With this configuration, when a positioning command is given to the controller 9, the first . The amount and direction of the current flowing through the coil elements 4a, 7a installed in the second slider 4.7 are controlled to operate as a linear motor, and the slider 4.7 operates as a linear motor.
Direct drive 7. Note that the current control is performed synchronously for the coil elements 4a of the pair of left and right first sliders 4, so that the first. The second sliders 4.7 move in the Y-axis and Y-axis directions toward designated positioning points, respectively, and the workpiece mounting table 6 is positioned at the designated position. Furthermore, in this case, positioning accuracy with high reliability can be achieved by providing a position detection sensor on the workpiece mounting table 6 and performing closed loop control.

Incidentally, since the positioning stop point is determined by the arrangement pitch of the permanent magnets 2, the finer the arrangement pitch on the χ and Y axes, the more positioning capacity can be provided.

In addition, the permanent magnets 2 arranged two-dimensionally on the base table 1 have a common field Fl for the sliders 4 and 7 on the x and Y axes.
Since the IM functions as a single stone, the sliders 4 and 7 can be arranged on the same surface, thereby making it possible to reduce the height dimension of the entire table device.

Embodiment 2: FIG. 4 shows an applied example of Embodiment 1 described above. That is, in the first embodiment, in order to move the second guide shaft 5 in the X-axis direction, the main shaft 5 is connected across two first sliders 4 arranged on the left and right sides. On the other hand, in the configuration shown in FIG. 4, one end of the second linear guide shaft 5 is connected to the first slider 4, and the other end is parallel to the first linear guide shaft 3 (in the X-axis direction) instead of the slider. It is supported by a magnetically levitated linear guide bearing 11 installed.

Here, the magnetically levitated linear guide bearing 11 has a permanent magnet 12 installed along the longitudinal direction on the inner periphery and upper and lower surfaces of a channel frame having a U-shaped cross section, and a linear guide shaft 5 facing the permanent magnet 12. Permanent magnets 13 are attached to the upper and lower surfaces of the end portions of the permanent magnets 13 so that the same polarity as that of the permanent magnets 12 faces each other. As a result, a magnetic repulsion force by the permanent magnets 12 and 13 acts between the guide shaft 5 and the bearing 11, and the guide shaft 5 is floated and guided in a non-contact manner. Further, in this embodiment, an electromagnet 14 is provided on the end face of the guide shaft 5, facing the channel frame (made of rope) of the guide bearing 11. This electromagnet 14 is not energized while the table device is moving, but is energized when the table device is stopped for positioning, and its magnetic attraction serves to lock the guide shaft 5 at the stopped position.

According to the second embodiment, compared to the first embodiment described above, the second embodiment
It is only necessary to provide one first slider 4 on one side of the base table 1 for moving and operating the guide shaft 5, and the configuration including the control system of the slider 4 can be simplified, and the other end of the guide shaft 5 can be magnetically Since it is supported by a floating guide bearing 11, no sliding friction is applied between the bearing and the bearing during movement.

Embodiment 3: FIGS. 5 and 6 show an embodiment in which an electromagnetic magnetic levitation bearing mechanism is used instead of the pressurized air levitation bearing shown in FIG. 3 in Embodiment 1.

This example is based on the first example. For the second linear guide shaft 3.5,
1st. The second slider 4.7 is guided and supported in a non-contact manner via an electromagnetic magnetic levitation bearing mechanism 15. Here, the magnetically levitated bearing mechanism 15 includes electromagnets 16 installed and installed in the upper, lower, and side surfaces facing the inner circumferential surface of the guide shaft 3.5, respectively, and the electromagnets 16 disposed in the upper and lower corners to maintain the distance between the slider and the guide shaft. In addition to the gap sensor 17 that detects the oscillation, an excitation controller 18 is also combined.

Here, based on the detection signal of the gear pump sensor 17, the excitation controller 1 day changes the excitation current of the upper and lower, left and right electromagnets 16,
That is, by individually controlling the magnetic attraction forces, the sliders 4 and 7 are magnetically levitated and guided in a non-contact manner with respect to the linear guide shaft 3.5.

Note that instead of installing the 1Mi stones 16 on the slider as in the illustrated example, a plurality of 1Mi stones 16 are installed. It is also possible to arrange magnets on the upper, lower, and side surfaces of the guide shaft 35 over the entire length thereof, and to guide and support the sliders 4 and 7 moving along the shaft in a magnetic levitation manner.

〔Effect of the invention〕

Since the positioning table device according to the present invention is configured as described above, it has a more effective effect than the conventional servo motor drive type device.

(1) Instead of a servo motor, we used a linear motor to directly drive the XY-axis sliders, so
There is no need for a rotation/linear motion conversion mechanism such as a feed gear, there is no backlash caused by feed gear, and the number of parts can be significantly reduced, simplifying the structure.1 In addition to reducing weight, it also provides lubricating oil. There are no parts that require maintenance, making it almost maintenance-free.

(2) This eliminates the accumulation of positioning errors caused by individual parts, ensuring high positioning accuracy.

(3) Furthermore, since the permanent magnets are arranged in a checkerboard pattern on the base table, these permanent magnets function as a field magnet for the near motor, which is common to each slider on the X and Y axes. Therefore, there is no need to stack the X-axis table and Y-axis table on top of each other, reducing the overall height, and since there is no part that protrudes outward from the table like a servo motor, the external shape is simple and the table bag 1 can be made compact. Can be configured.

(4) On the other hand, since the slider is guided and supported in a non-contact manner with respect to the straight 1s guide shaft via a magnetically levitated bearing mechanism, high positioning accuracy can be ensured without being affected by sliding friction, and It can also be used in vacuum chambers, where static pressure type bearings cannot be used.

[Brief explanation of drawings]

Fig. 1 is a perspective configuration diagram of one embodiment of the present invention, Fig. 2 is a sectional view of Fig. 1, Fig. 3 is a diagram of a hydrostatic guide type bearing mechanism, and Fig. 4 is a configuration sectional view of another embodiment. , FIG. 5 is a cross-sectional view of the configuration of an embodiment employing an electromagnetic magnetic levitation bearing mechanism, and FIG. 6 is a front view of the magnetic levitation bearing mechanism between the second guide shaft/slider in FIG. 5. In, 1: base table, 2: permanent magnet, 3: first linear guide shaft, 4: first slider, 4a: coil element, 5: second linear guide shaft, 6: workpiece mounting table, 7: Second slider, 7a: Coil element, 8: Controller, 11
: Magnetic levitation linear guide bearing, 15: Electromagnetic magnetic levitation bearing mechanism, 16: Electromagnet, 17: Gap sensor, 18:
Excitation controller. Figure 2 Figure 3 Side magnetic fishing

Claims (1)

[Claims] 1) A table device for positioning a workpiece mounting table by moving it in the X-axis and Y-axis directions based on a command, which includes a base table made of a magnetic material, and an X-axis,
A group of permanent magnets arranged in a grid pattern with N and S poles arranged alternately parallel to the Y axis, and X and Y magnets installed on a base table.
a first linear guide shaft parallel to one of the axes; a first slider supported on the guide shaft and provided with a coil element on a surface facing the permanent magnet group; and a first slider connected to the slider. a second linear guide shaft perpendicular to the guide shaft; a second slider supported on the second guide shaft and provided with a coil element on a surface facing the permanent magnet group; 1. A positioning table device comprising a workpiece mounting table mounted on a slider, and moving and positioning the workpiece mounting table to a specified position by controlling energization of coil elements of the first and second sliders. 2) In the positioning table device according to claim 1,
A positioning table device characterized in that one end of the second linear guide shaft is connected to the first slider, and the other end is supported by a magnetically levitated guide bearing installed parallel to the first linear guide shaft. 3) In the positioning table device according to claim 1,
A positioning table device characterized in that first and second sliders are guided and supported in a non-contact manner with respect to first and second linear guide shafts via electromagnetic magnetic levitation bearing mechanisms, respectively.