JPH06320367A - Positioning table device - Google Patents

Abstract

PURPOSE:To provide constitution of a positioning table device the size of which is reduced as the whole including space and which is designed to perform high- precise positioning with excellent reproducibility and at a high speed. CONSTITUTION:A positioning table device comprises a base table 1 provided on its upper surface with a magnetic pole surface in whose square region, permanent magnets 2 are laid in a checkboard-like state; two X-axis directional guide shafts 3 supported on the base table 1 along the parallel two sides of the square region; two sliders 4 moving in non-contact with a guide shaft along the respective guide shafts 3; and a Y-axis directional guide shaft 7 the both end parts of which are fixed to the X-axis directional slider 4. Further, the device comprises an Y-axis directional slider 8 moving in non-contact with a guide shaft 7 along the guide shaft 7; and a linear motor consisting of coil elements 4a and 8a arranged on the under surface of each slider and a checker board-like magnetic pole surface. Guide shafts are provided, on their sides with linear scales 5 and 9 respectively and detecting bodies 6 and 10 to detect an own position by utilizing the linear scales are carried on the sliders 4 and 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a positioning table device which is applied to an assembling apparatus, a precision machine tool, an optical component assembling apparatus, and the like, and which brings a mounted object to be moved to a designated position by moving in the X and Y biaxial directions.

[0002]

2. Description of the Related Art Since a positioning table device such as a semiconductor manufacturing device requires a highly accurate positioning of 1 μm or less,
An X-axis direction moving table and a Y-axis direction moving table are superposed in this order on the base table in the vertical direction via needle rollers with less friction and dust generation, and the work table is moved by the movement of both moving tables. Generally, the structure is such that each moving amount of both moving tables is controlled while measuring the moving amount of the moving object.

FIG. 5 is a schematic perspective view showing an example of the configuration of a conventional positioning table device. This structure includes a base table 17, a first movable table 18 bearing-guided on the base table 17 in the X-axis direction, and a bearing guided on the first movable table 18 in the Y-axis direction orthogonal to the X-axis. The second moving table 19 and the work mounting table mounted on the second moving table 19 are vertically stacked and assembled, and the first movement is performed by using the servo motors 23 and 27 and the feed screw mechanisms 22 and 26. The table 18 and the second moving table 19 are respectively the base table 17,
The work attachment table 28 is positioned at a designated position by moving the first movement table 18 in the X-axis and Y-axis directions. Reference numeral 35 in the drawing denotes a needle-shaped roller row fitted to the slope of the V-shaped groove formed on the upper surface side of the base table 17 for guiding the movement of the first moving table 18 in the X direction, 36 is the first and second moving table 1
Needle-shaped roller row that supports about 1/2 of the total weight of the moving object (not shown) (hereinafter, also referred to as a work)
Is a needle roller row fitted on the slope of the V-shaped groove formed on the upper surface side of the first moving table 18, 39 is about 1 of the total weight of the second moving table 19 and the work (not shown).
It is a needle-shaped roller row that supports / 2.

Further, the movement amount of the work mounting table 28 is controlled by the frequency stabilizing laser light source 2 for stabilizing the frequency.
The laser light emitted from 9 is split in the X and Y directions by the demultiplexer 34, and the split laser light is used as the primary light incident on the first interferometer 30 and the second interferometer 32, respectively. The light exits from the interferometer 30 and the second interferometer 32, respectively, is reflected by the first reflecting mirror 31 and the second reflecting mirror 33 attached to the work attaching table 28, and is again reflected by the first interferometer 30 and the second The laser light incident on the interferometer 32 is used as the secondary light, and is measured from the phase difference between the primary light and the secondary light. Then, the two servo motors 23 and 27 are driven until the current value of the position of the work mounting table 28 measured by the laser beam and the designated position set from the outside coincide with each other, thereby realizing highly accurate positioning.

[0005]

By the way, in the above-mentioned general positioning table device driven by a servo motor,
There are the following difficulties. (1) Since the base table, the first moving table, and the second moving table are vertically stacked, the height of the entire table device is large, the load weight is heavy, and a large torque is required for the servo motor. .

(2) The method of measuring the amount of movement of the work mounting table using laser light requires expensive optical equipment such as a laser light source, an interferometer, and a reflecting mirror. If the installation space is secured, the positioning table device cannot be downsized. (3) It is difficult to adjust the optical axis of the laser beam parallel to the moving axis direction (X-axis direction, Y-axis direction) in the measurement using the laser beam, and it is necessary to adjust this optical axis in order to obtain reproducible measurement accuracy. Requires. Also, since the optical path length of the laser beam is generally longer than the movement amount of the work mounting table, environmental changes in the optical path length of the laser beam (room temperature, humidity, air fluctuations)
Are likely to be affected by, and the measurement accuracy is likely to deteriorate.

(4) A rotation / linear conversion mechanism such as a feed screw mechanism is required between the servo motor and the table in order to linearly move the table by driving the servo motor.
The structure becomes complicated, and the backlash of the feed screw mechanism causes a decrease in positioning accuracy. (5) Further, since the table device configured as described above uses the contact type linear guide bearing and the feed screw, the table device easily generates heat. Therefore, in the case of performing highly accurate positioning, a method of moving the moving table at a low speed to suppress heat generation is adopted.

The object of the present invention is to reduce the size of the entire apparatus including the space required for the apparatus configuration, and to configure a positioning table apparatus capable of high-accuracy positioning easily, with good reproducibility, and at high speed with little influence of the apparatus environment. Is to provide.

[0009]

In order to solve the above-mentioned problems, there is provided a positioning device for moving a movable body on a base table in the X-axis direction and the Y-axis direction to bring it to a designated position.
One base table in which a plate-shaped or columnar permanent magnet having a rectangular pole surface shape is laid in a square pattern so that the polarities of adjacent magnetic pole surfaces are different from each other and fixed to the upper surface in a rectangular region of a flat upper surface; Is provided with a linear scale on the side surface along the longitudinal direction for detecting the position in the longitudinal direction of an object adjacent to the side surface.
Two first guide shafts fixed to the base table along the sides and straddling the opposite two sides perpendicular to the opposite two sides; and in non-contact with the guide shafts respectively along the first guide axes; A coil element is attached to the lower part so that the coil surface faces the grid-shaped magnetic pole surface to form a linear motor together with the grid-shaped magnetic pole surface, and the position of the single guide shaft in the longitudinal direction is the guide shaft. Two first sliders carrying a detection body for detection using a linear scale on the side surface; a longitudinal direction formed at the same structure as the first guide shaft and perpendicular to the longitudinal direction of the first guide shaft. A second guide shaft whose both ends are respectively fixed to the two first sliders so as to have the same structure as that of the first slider carrying the detection body and to be moved. Workpiece mounting on which the body is placed A second slider having a Buru;
And the first and second sliders are provided with a position detection function and a drive function for the moving body.

Here, the linear scales on the side surfaces of the first and second guide shafts are arranged in the longitudinal direction to form a diffraction grating, and the linear scale is used as a detector to detect a position from the light source and a light receiving element. The photoelectric detection head is extremely suitable. In addition, the non-contact moving structure that allows each slider to move in a non-contact manner along each guide axis includes a linear scale on the upper surface of the guide shaft, the side surface not having the linear scale, and the side surface having the linear scale. , While being formed flat over the entire axial length,
The slider is provided with an air bearing surface and a guide shaft that face the guide shaft upper surface and the side surface, respectively, and have air inlets that penetrate the facing surfaces and introduce compressed air from the outside. It is extremely suitable to use a static pressure levitation moving structure that moves the slab to the above position.

[0011]

By configuring the positioning movement table as described above, (1) it corresponds to the first slider corresponding to the conventional X-axis (Y-axis) direction movement table and the Y-axis (X-axis) direction movement table. The second slider can be configured to move at the same height on the upper surface side of the base table, and the height of the device can be made lower than in the conventional case.

(2) A coil element is attached to the lower part of the slider so that each slider can be moved in a non-contact manner along each guide shaft, and a linear motor is constructed by combining with a grid-shaped magnetic pole surface on the base table surface. By doing so, the slider is moved without any contact with the fixing member of the apparatus, and the slider does not generate heat even when the object to be moved mounted on the second slider is moved at high speed. Will be possible.

(3) For positioning, one of the two first guide shafts and the second guide shaft are provided with linear scales on their respective side surfaces, and the linear scales are used to guide the user. If the slider carries a detector for detecting the position in the longitudinal direction of the shaft, the position of the slider in the longitudinal direction of the guide shaft can be directly measured, and adjustment as in the case of using a laser beam for position detection can be performed. Highly reproducible measurement can be performed without need and without being affected by the device environment such as room temperature and air fluctuation. Further, expensive measuring means such as a laser device and an optical device which are conventionally required are not required.

Further, the linear scales on the side surfaces of the first and second guide shafts are arranged in the longitudinal direction, and a detector for detecting the position of the linear scale using the linear scale is combined with a light source and a light receiving element. As a detection head,
If the position of the movable body is optically detected, the position can be detected without being disturbed by the magnetic flux upward from the grid-shaped magnetic pole surface on the upper surface of the base table, and high-precision positioning is facilitated. .

Furthermore, a non-contact moving structure that allows each slider to move in a non-contact manner along each guide shaft is provided with a linear upper surface, a side surface without a linear scale and a side surface with a linear scale. A levitation device that includes a scale, is formed flat over substantially the entire axial length, and has a slider that has an air inlet that faces the upper surface and side surfaces of the guide shaft and that penetrates the facing surfaces and introduces compressed air from the outside. If a static pressure levitation moving structure is provided in which the slider and the guide surface are provided so that the slider floats and moves in a non-contact manner, the air inlet of compressed air introduced from the air inlet of the slider's air bearing surface and guide surface By keeping the static pressure constant, the flying height of the air bearing surface and the gap between the guide surface and the side surface of the guide shaft can be maintained with high accuracy. , The gap between the slider lower part and the grid-shaped magnetic pole surface is maintained with high precision and accuracy, and the fluctuation of the surface-direction driving force becomes extremely small when the relative surface position of the slider and the grid-shaped magnetic pole surface is the same. The accuracy of the slider movement amount based on the position detection signal is improved. When the linear scale on the side surface of the guide shaft is used as the diffraction grating, a fine pitch scale line is formed by vapor deposition in the premises with a depth of about 100 μm formed on the flat side surface when forming the diffraction grating. It is easily possible to form the axial side surface to be flat, including the linear scale.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the entire configuration of the apparatus. A base table 1 which is a base of the apparatus main body is a substantially rectangular shape and is formed in a rectangular area on the upper surface of a plate body made of a magnetic material such as a steel plate. , A plate-shaped or columnar permanent magnet 2 having a square pole face shape is laid in a grid pattern so that adjacent pole faces have different polarities as shown in the figure, and is integrated with a plate body by using an adhesive or the like. Is. On the upper surface side of the base table 1, two first guide shafts 3, which will be described in detail below, are provided along the two parallel sides of the rectangular region in the X direction.
It is supported on the base table 1 across two parallel sides of the direction via a guide shaft support 3a. The first guide shaft 3 guides the movement of the first slider 4 in the X direction, and has a substantially rectangular cross section, and the first slider 4 has a short rectangular tubular shape surrounding the guide shaft 3. The air is pressure-fed from the outside through an air introduction port (not shown) formed on each peripheral wall surface of the rectangular tube, and the first slider 4 has a distance of several tens of μm between its upper surface and the upper surface of the guide shaft 3. And is kept in non-contact with the guide shaft 3.

A second guide shaft 7 formed in the same structure as the first guide shaft 3 is fixed at its both ends to the first slider 4 so as to be orthogonal to the first guide shaft 3, The movement of the second slider 8 in the Y direction is guided. The second slider 8 is also the first
The slider 4 is formed in the same structure as the slider 4 and is held in a non-contact state with the second guide shaft 7 by the air pressure-fed from the air introduction port of each peripheral wall surface. A work mounting table 11 is fixed to the upper surface of the second slider 8.

FIG. 3 shows the orientation of the detector for detecting the position of the moving body, and FIG. 4 shows an enlarged view of the detector. As shown in FIG. 4, one of the first guide shafts 3 (on the right side in FIG. 3) and one side face of the second guide shaft 7 are
Depth is about 100μ to facilitate the deposition of the contact grid.
m groove is formed, and a diffraction grating is formed by vapor deposition in this groove to a thickness of about 100 μm, and the side surface is flattened over the entire axial length. The diffraction grating forms a linear scale on the side surface of the guide shaft by making the arrangement direction the same as the moving direction of the sliders 4, 8.

The first and second sliders 4 and 8 facing the linear scales 5 and 9 respectively emit a light emitting element 14 that emits a coherent light beam and the coherent light diffracted and reflected by the linear scales 5 and 9. The detection bodies 6 and 10 including the detection element 15 that receives a light beam are attached by an adjustment spring 17 and a cap screw 16 so that the inclination of the entire detection body with respect to the linear scale can be finely adjusted. The positions or movement amounts of the sliders 4 and 8 in the longitudinal direction of the guide axis are determined by the diffraction and reflected light from the diffraction gratings that form the linear scales 5 and 9.
It is measured by detecting with the detection element 15 that moves integrally with the sliders 4 and 8.

As shown in FIG. 2, thin flat plate-shaped coil yokes 4b and 8b are fixed to the lower surfaces of the first and second sliders 4 and 8 each formed in a rectangular tube shape. , The X-axis coil element 4a and the Y-axis coil element 8a are fixed to the lower surfaces of the coil yokes 4b and 8b, respectively.
The permanent magnet 2 on the upper surface of the base table 1 and the coil yoke 4
b, 8b and coil elements 4a, 8a constitute a linear DC motor.

In FIG. 2, the detection signals from the detectors 6 and 10 which detect the diffraction and reflected light from the linear scales 5 and 9 in the X-axis and Y-axis directions, respectively, are detected by the X-axis of the controller separate from the apparatus main body. Input to the axis counter and Y-axis counter respectively, the position in the X-axis direction and the position in the Y-axis direction are respectively detected, and the electric quantity with positive and negative polarities corresponding to the difference between this position and the designated position is calculated by the motor control unit. Then, this electric quantity is applied to the coil elements 4a and 8a of the linear DC motors 12 and 13.
Sent to. As a result, the sliders 4 and 8 move in the X-axis and Y-axis directions corresponding to this amount of electricity, and in the direction indicated by the polarity of the amount of electricity.

[0022]

According to the present invention, since the positioning table device is constructed as described above, the following effects can be obtained. In the apparatus according to claim 1, (1) the first and second sliders corresponding to the conventional X-axis direction and Y-axis direction moving tables, respectively, can be structured to move at the same height on the upper surface side of the base table. In addition, the height of the device can be made lower than that of the conventional one, and the position of the moving object can be detected within the moving area of the first and second sliders, and the laser that requires a long optical path length for position detection. It does not require as much space for the detection means as it does with the light beam. As a result, the positioning table device is downsized as a whole, an extra installation space is generated, and this extra space can be effectively utilized.

(2) Since each slider can be moved along each guide shaft in a non-contact manner, and each slider is driven by a linear motor arranged below the slider, the slider is fixed to the fixing portion of the apparatus. Since it can be moved in a completely non-contact manner and heat is not generated even if the slider is moved at a high speed, high-speed positioning is possible and the throughput of the manufacturing apparatus using the positioning table device is improved. In addition, since there is no movement error due to backlash of the screw rod when the movable body is moved, high-accuracy positioning is possible, and the quality of the processed movable body is made uniform at a high level.

(3) Since the linear scale is provided on the side surface of the guide shaft and the detection body facing the linear scale is carried on the slider to enable the position detection of the slider, the position of the slider is directly detected. It enables highly reproducible measurement without requiring difficult adjustments such as when using a laser beam for position detection, and less susceptible to the device environment such as room temperature and air fluctuations. The quality of the moving object processed at the position is likely to be uniform. In addition, the cost of the device is reduced because an expensive measuring device such as a laser device or an optical device is not required.

In the apparatus according to the second aspect, the position of the movable body can be detected without being disturbed by the magnetic flux upwardly emitted from the cross-shaped magnetic pole surface on the upper surface of the base table, and the detection accuracy is improved. The quality level of the moving object is made uniform. According to the apparatus of claim 3, the static pressure at the air inlet of air introduced between the guide shaft surface and the slider air bearing surface and the guide surface is kept constant, so that the guide shaft surface and the slider air bearing surface, the guide surface. Since the gap with the surface is kept constant with high accuracy, the in-plane distribution of the linear motor driving force becomes stable, the fluctuation of the moving distance for the same moving amount signal obtained by the position detection signal becomes small, and the movement amount The accuracy is improved, and the uniformity of the quality level of the moving object is improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the configuration of a positioning table device according to the present invention.

FIG. 2 is a configuration diagram of a moving body moving system showing a method of detecting and moving a position of a moving body according to the present invention.

FIG. 3 is a detection unit configuration diagram showing the configuration of a detection unit for detecting the position of a moving object according to the present invention.

FIG. 4 is an enlarged view of the detection unit in FIG.

FIG. 5 is a perspective view showing an example of the configuration of a conventional positioning table device.

[Explanation of symbols]

 1 base table 2 permanent magnet 3 first guide shaft 3a guide shaft support 4 first slider 4a coil element 4b coil yoke 5 first linear scale 6 first detector 7 second guide shaft 8 second Slider 8a Coil element 8b Coil yoke 9 Second linear scale 10 Second detection body 11 Work mounting table 12 Linear motor 13 Linear motor 14 Light source 15 Light receiving element

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H02K 41/02 C 7346-5H

Claims (3)

[Claims] 1. A base in which a rectangular plate-shaped or columnar permanent magnet having a magnetic pole surface shape is laid in a square shape on a flat upper surface so that adjacent magnetic pole surfaces have different polarities, and fixed to the upper surface. A table; one is provided with a linear scale on a side surface along the longitudinal direction for detecting a longitudinal position of an object adjacent to the side surface, the table being along two opposite sides of a rectangular area of the table surface and the opposite side 2 Two first guide shafts fixed to the base table straddling two opposite sides in a direction perpendicular to the side; and a coil surface on the lower part which is movable along the first guide shafts in a non-contact manner with the guide shafts. A coil element is mounted so that it faces the board-shaped magnetic pole surface to form a linear motor together with the board-shaped magnetic pole surface, and the position of the guide shaft in the longitudinal direction from one side is determined by the linear scale on the side surface of the guide shaft. 2 was supported detector for detecting and
A plurality of first sliders; both ends of the first slider are respectively formed in the same structure as the first guide shaft so that the longitudinal direction is perpendicular to the longitudinal direction of the first guide shaft. A second guide shaft that is fixed; a second slider that is formed in the same structure as the first slider that carries the detection body and that has a work mounting table on which the movable body is mounted. A positioning table device, characterized in that the first and second sliders are provided with a position detecting function and a driving function of the moving body. 2. The positioning table device according to claim 1, wherein the linear scales on the side surfaces of the first and second guide shafts are arranged in the longitudinal direction by using a diffraction grating and a linear scale to determine the position of the linear scale. A positioning table device, wherein a detection body to be detected is a photoelectric detection head in which a light source and a light receiving element are combined. 3. The positioning table device according to claim 1 or 2, wherein the non-contact moving structure that allows each slider to move in a non-contact manner along each guide shaft includes a top surface of the guide shaft and a linear structure. Includes a linear scale on the side without the scale and the side with the linear scale,
The air bearing surface and the guide surface are formed flat over substantially the entire length in the axial direction, and have an air inlet that faces the upper surface and side surfaces of the guide shaft and penetrates through the facing surfaces to introduce compressed air from the outside. And a static pressure levitation moving structure that floats the slider and moves the slider in a non-contact manner.