JPS60223119A - Noncontacting driving type precise moving base - Google Patents

Abstract

PURPOSE:To obtain a moving base having ultra-high accuracy not affected by the vibration and heat of a driving section by transmitting the power of a power source over a moving table through a noncontacting joint, forming a predetermined clearance between a sliding shaft and the moving table and sliding the moving table in a noncontacting manner. CONSTITUTION:A magnet 17 is moved rectilinearly by flowing currents through a linear coil 16. Several dozen kg sucking force works between the linear coil 16 and the magnet 17 at all time in case of said rectilinear movement. The sucking force is supported by a rectilinear bearing 24 while the pulsation displacement of the magnet 17 is constrained, thus resulting in rectilinear movement with high accuracy. The transfer (driving force) of the magnet 17 is transmitted over a moving table 14 by a noncontacting joint 20, and the moving table 14 is shifted slowly under the state in which a clearance (g) is maintained along a sliding shaft 12. With the transmission of power over the moving table 14 by said noncontacting joint 20, the vibration of the magnet 17 is absorbed by a clearance (h) while the clearance (h) conducts a kind of heat-insulating action, and heat transfer is relaxed. The moving base is used for the production of a semiconductor, the production of a machine for superfine machining or superfine measurement.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to the improvement of a moving table for performing ultra-precision machining or measurement. This invention relates to a moving platform with improved accuracy.

[Background of the invention]

For example, ultra-precise sample (work) moving tables are used in semiconductor exposure apparatuses, ultra-precision machining machine tools, precision measuring instruments, etc., depending on the accuracy of each.

The most commonly used mobile cart is shown in FIG. 1 and will be described below.

In the figure, this movable table feed screw 1 and motor 2 are used. That is, the rotation of the motor 2.

The nut 5 screwed into the feed screw 1 converts the motion into linear motion, and the slider 4 fitted onto the slide shaft 6 is moved with high precision.

However, at present, it is used as a wafer moving table in semiconductor exposure equipment, a moving table for workpieces or tools such as ultra-precision grinders and lathes, and a moving table for precision measuring instruments such as straightness measuring instruments. fi>Ln, accuracy of 0.05 μm or less is required, and heat and vibration from the drive system or movement error of the driven object have a large effect. The reality is that it is impossible to achieve b.

To explain in more detail the feed screw system shown in FIG.
The slider 4 is vibrated and thermally deformed.

In addition, when the slider 4 moves along the slide shaft 6 due to play in the bearing 5 that pivotally supports the feed screw 1 and errors in parallelism between the moving direction of the slider 4 and the feed screw 1, High precision movement is not possible due to external fluctuations.

In addition, the feeding screw method has many mechanical elements and connection processing parts, which reduces the rigidity of the drive system, and requires dust-proof measures for precision feeding, which also poses problems in terms of maintenance. be.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide an ultra-high precision moving table that is not affected by vibrations or heat of the drive unit.

[Summary of the invention]

That is, in order to avoid transmission of vibration and conduction of heat, the present invention
The driving force from the drive source is transmitted to the moving table via a non-contact joint, and the moving table and guide shaft are also non-contact to reduce the effects of vibration and heat. A movable table designed to eliminate mechanically derived external fluctuations, with a hydrostatic bearing pad on its inner surface, and a slide shaft inserted through the hydrostatic bearing pad of the movable table with a certain gap. The movable table can be slid in a non-contact manner,
The present invention is characterized by a button that transmits the driving force of a driving source that generates linear displacement to the movable table via a non-contact type joint.

[Embodiments of the invention]

An embodiment of the present invention will be described in detail below.

#! 2 and 3, a hydrostatic bearing pad 13 having a large number of air supply holes or air supply grooves 13' is formed on the inner surface of the movable table 14. Reference numeral 12 denotes a slide shaft made of a hollow rectangular prism, which is inserted into the stationary bearing pad 13 with a one-leg gap g. Reference numeral 19 denotes a slide pad), which is coupled to or integrally formed with the hydrostatic bearing pad 13.

This slide pad 19 is also provided with an air supply hole or air supply groove 19'. Reference numeral 21 denotes an escape groove provided to allow the slide pad 19 to escape.
This is because the movable table 14 is movable along the slide shaft 12.

16 is a linear coil fixed to the casing 22;
7 is a magnet suspended from the housing 23 via a linear bearing 24. This linear coil 16 and magnet 17 [A linear motor 15 is formed in the hollow part of the L slide shaft 12. 18 is.

- Between the legs! The opposing plate is erected on the magnet 19 so as to sandwich the slide pad 19 with Jh, and the driving force of the magnet 17 is thereby transmitted to the slide pad '19. That is, the slide pad 19 and the opposing grate 18 form a non-contact type joint 20.

Reference numeral 25 denotes a cushioning material, which has high rigidity in the moving direction of the magnet 17 and low rigidity in the direction perpendicular to the moving direction.

Note that 11 is a base block for supporting the slide shaft 12.

The operation of this embodiment configured as above will be explained below. For example, by force-feeding air in the direction of arrow (a), the movable table 14 can be moved to a gap g relative to the slide shaft 12.
held in a non-contact state. Similarly, there is a gap of 1! between the slide pad 19 and the opposing grate 18! The non-contact joint 20 is formed with Jh maintained. In this case, in the air supply hole or air supply groove 13' or 19' (air throttling method),
There are self-drawing methods, orifice drawing methods, and surface drawing methods.

In this case, it is advisable to keep the rigidity of the hydrostatic bearing pad 13 and the slide pad 19 high, and to use a surface constriction system that has a high load capacity and low air consumption. ``Next, the moving table 14 is moved in a linear manner.

When current is applied to the linear coil 16, the magnet 17 moves straight. in this case.

between the linear coil 16 and the magnet 17.

Suction power of several 10 kg is always working. This attractive force is supported by the linear bearing 24, and the pulsating displacement of the magnet 17 is restrained, resulting in highly accurate linear movement. This movement (driving force) of the magnet 17 is transmitted to the moving table 14 by the non-contact joint 20, and the moving table 14 moves quietly along the slide shaft 12 while maintaining the distance @g.

In the transmission of power to the movable table 14 by the non-contact joint 20, the vibration of the magnet 17 is absorbed by the gap ih, and the gap i*h acts as a kind of heat insulation, thereby relaxing heat conduction. Similarly, in the case of the movable table 14 that slides on the slide shaft 12 while maintaining a constant gap g, there is no loss of vibration and no heat conduction due to one gap g, and there is no stick-slip lag. You can get a good driving experience.

Furthermore, when the moving table 14 and the slide shaft 12 are made of ceramic material, there are the following advantages.

For example, alumina ceramic material is lightweight with a specific gravity of 6.5 or less compared to other metals, has a low coefficient of thermal expansion, and has a high hardness. It has the advantage of being easy to achieve machining accuracy.

Therefore, when the movable table 14 and the slide shaft 12 are made of alumina ceramics, they can be processed with high accuracy by reducing the gap (11g) by 9cm, and are lightweight and highly rigid, allowing for highly accurate running performance. .

Fig. 4 shows an example applied to an X-Y stage).

65 is an X-movement table, and 54 is its slide axis.

31 is an X-movement table, and 32 is its guide shaft. Further, 37 is a linear motor, and 58 is a non-contact joint. In addition,
30 is an XY stage, 35 is a pace, and 36 is a sample stage.

FIG. 5 shows an example applied to a three-dimensional measuring machine 4a. In the figure, 31 is an X-movement table, and 32 is its slide axis. 33 is an X movement table.

54d is its slide shaft. 43 is 2 moving table 4
2 is its slide axis. In the figure, 37 is a near motor, and 41 is a sample.

C invention ah effect no According to the moving table according to the present invention, which has been described in detail above.

The power of the power source is transmitted to the moving table via a non-contact joint, and a certain gap is provided between the slide shaft and the moving table to allow non-contact sliding.
The vibration of the drive source was cut off, and the conduction of heat was also alleviated, making it possible to obtain a highly accurate moving platform.

In addition to solving the problems of vibration and heat, the movable table can now run smoothly and has even higher precision.

In this way, by obtaining a highly accurate moving table, it becomes possible to produce semiconductors, produce ultra-precision processing machines, realize ultra-precision measurement, etc., and has a great effect on industrial development.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a moving table using a feed screw type, which is a typical conventional moving table. 2 to 5 show one embodiment of the present invention, in which FIG. 2 is a longitudinal cross-sectional view of the moving platform, and FIG. 3 is a cross-sectional view taken along line A-Alil in FIG. 2. FIG. 4 #'i1 A perspective view when this embodiment is applied to an XY stage The s'igs diagram is a perspective view when the present embodiment is applied to a three-dimensional stage. 12...Slide shaft, 13...Static pressure bearing pad. 14...Moving table, 15...Linear motor, 1
6... Linear coil, 17... Magnet, 18.
・・Opposing grate, 19・・Slide pad, 20・
...Non-contact joint, 21... Relief groove, 22... Casing, 23... Housing, 24... Linear bearing, 2
5. Cushioning material. Figure 1 Figure 2 Figure 4 Figure 5

Claims (1)

[Claims] (1) A moving table having a hydrostatic bearing pad on its inner surface;
A slide shaft that is inserted into the hydrostatic bearing pad of the movable table with a certain gap and slides the movable table without contact, and a slide shaft for transmitting the driving force of the drive source that generates linear displacement to the movable table. A non-contact type precision moving table consisting of a non-contact type joint. (2. Non-contact part moving type, characterized in that the hydrostatic pressure bearing pad and the non-contact type joint described in claim 1 are respectively a hydrostatic pressure air bearing pad and a non-contact type air joint) Precision moving table. (3) Ij=
A non-contact movable platform that uses an amotor and is characterized in that the linear motor is built into a hollow slide shaft. (4) A non-contact movable moving table characterized in that the moving table and slide shaft according to claim 1 are made of a ceramic material.