JP2008145140A - Planar stage with magnetic flux sensor and magnetic flux sensor - Google Patents

Abstract

In a planar stage using a surface motor stage device or the like, a lightweight and inexpensive planar stage including a magnetic flux sensor with a simple structure is provided for measuring a moving distance of a moving body.
A planar stage including a platen 8 on which convex poles made of a magnetic material are formed at equal intervals, a moving body 2 that floats and moves on the platen 8, and a control unit 9 that controls the moving body 2. 1, the comb 2 has a plurality of convex portions that are made of a magnetic material, have a pitch that is an integral multiple of the pitch of the convex poles of the platen 8, and have the same width as the width of the convex poles. Formed with a magnetic body, magnetic flux generating means for generating magnetic flux in the comb-like portion, and magnetic flux measuring means for measuring a change in magnetic flux of the comb-like portion and outputting the result, A magnetic flux sensor 7 is provided in which the convex portions of the comb-like portion are arranged so as to face the platen 8, and the control unit 9 calculates the moving distance of the moving body 2 based on the output measured by the magnetic flux measuring means. This is a flat stage characterized by this.
[Selection] Figure 1

Description

  The present invention relates to a magnetic flux sensor and a flat stage including the magnetic flux sensor, and more particularly, to a flat stage including a magnetic flux sensor that measures a moving distance of a moving body that moves in a non-contact manner on a platen in a non-contact manner.

Conventionally, as shown in Patent Document 1 and Patent Document 2, a moving body is levitated by air on a flat platen provided with ferromagnetic convex poles, and a magnetic force is applied to the moving body. A flat stage configured to move the moving body by changing the magnetic force between the moving body and the convex pole of the platen is known.
In the planar stage, one surface of the movable body is a work stage for placing a workpiece, and thus is planarized with high accuracy. The other surface is provided with a magnetic pole that generates a moving magnetic field in each axial direction of orthogonal coordinate axes and an air pad that blows out air.
The magnetic pole and air pad of the moving body are arranged so as to face the convex pole of the platen, and the moving body floats by the action of air. In this state, a moving magnetic field is generated on the magnetic pole of the moving body, and the moving body moves on the platen by changing the magnetic field between the magnetic pole and the convex pole of the platen.
In addition, the apparatus which has such a structure may be called a surface motor stage apparatus, a Soya motor stage apparatus, etc.

Such a flat stage is different from a conventional stage device having a configuration using a ball screw, on a single stage made of a platen plane without overlapping a plurality of stages with an X stage, a Y stage, and a θ stage. The moving body can be moved in the XY direction and rotated about an axis perpendicular to the XY plane.
Therefore, in recent years, application to a work stage of a sequential (step-and-repeat) exposure apparatus that moves and exposes a work divided into a plurality of exposure areas in the order of the divided areas has been studied. In an exposure apparatus using a flat stage as a work stage, the structure of the work stage becomes simple, and it is expected that the apparatus can be reduced in size and weight.

The principle of operation of the planar stage will be briefly described with reference to FIGS. FIG. 6 is a cross-sectional view showing a platen 10 having a plurality of convex poles and a moving element 20 having magnetic poles constituting a planar stage, and FIG. 7 is a timing chart of currents flowing in coils wound around the magnetic poles of the moving element 20. is there. 7 indicates the direction of current flowing through the coil, and the current pattern in FIG. 7 is merely an example, and the current may be changed smoothly as represented by a sine wave.
As shown in FIG. 6, the platen 10 has a planar plate shape, and the ferromagnetic convex poles 11, 12,... Are provided in a grid pattern. The space between the convex poles is filled with a nonmagnetic material 10a. A permanent magnet 21 is attached in the magnetic path of the moving element 20, and thereby N or S magnetic poles are generated in the four magnetic poles 22 a to 22 d provided in the moving element 20.
Coils 23a and 23b are wound around the magnetic poles 22a to 22d, and when a current is passed, the magnetic poles 22a to 22d become electromagnets. If the direction of the magnetic field generated by the permanent magnet 21 and the direction of the magnetic field generated by the electromagnet are the same, the magnetic forces are strengthened. If the magnetic field generated by the permanent magnet 21 and the magnetic field generated by the electromagnet are opposite, the magnetic force is canceled.

The coil 23a is wound in the opposite direction between the magnetic pole 22a and the magnetic pole 22b. Therefore, when a magnetic field in the same direction as the magnetic field generated by the permanent magnet 21 is generated in the magnetic pole 22a and the magnetic forces are strengthened, a magnetic field in the opposite direction to the magnetic field generated by the permanent magnet 21 is generated in the magnetic pole 22b, and the magnetic force is canceled out. . The same applies to the magnetic pole 22c and the magnetic pole 22d. The magnetic poles 22a to 22d of the mover 20 are placed facing the convex poles 11, 12,. The mover 20 is lifted from the platen 10 by the action of an air pad that blows out air, but the air pad is omitted in FIG.
The upper surface of the mover 20 is a surface on which the workpiece is placed. In some cases, the workpiece is placed directly on the movable element 20, but in some cases, a planar work stage is placed on the upper surface of the movable element 20 and the workpiece is placed thereon.

  A moving magnetic field is generated by applying a current in the following order to the coils 23a and 23b wound around the magnetic poles 22a to 22d in the following order, and the moving element 20 moves in the left-right direction in FIG. Hereinafter, the principle of operation in which the moving element 20 moves in the right direction of the drawing will be described.

(1) STEP 1: As shown in FIG. 7, a current is passed through the coil 23a on the magnetic poles 22a and 22b side of the moving element 20 so as to increase the magnetic force of the magnetic pole 22a. No current flows through the coil 23b of the magnetic poles 22c and 22d. Since the magnetic force of the magnetic pole 22a is increased, the magnetic pole 22a attracts strongly to the convex pole 11 of the platen 10, and the magnetic pole 22a and the convex pole 11 are in a position facing each other. The magnetic pole 22 b is positioned on a nonmagnetic material between the convex pole 12 and the convex pole 13 because the magnetic force is canceled. The magnetic pole 22c and the magnetic pole 22d attract the convex poles 14 and 16 in the oblique direction, respectively.

(2) STEP 2: As shown in FIG. 7, the current in the coil 23a of the magnetic poles 22a and 22b is stopped, and the current is passed through the coil 23b on the magnetic poles 22c and 22d side so as to increase the magnetic force of the magnetic pole 22d. The magnetic pole 22 d attracts strongly with the convex pole 16, and the magnetic pole 22 c cancels the magnetic force and does not attract with the convex pole 14. Therefore, the mover 20 moves to the right in the figure so that the magnetic pole 22d faces the convex pole 16. The magnetic pole 22a and the magnetic pole 22b attract the convex poles 11 and 13 in the oblique direction, respectively.

(3) STEP 3: As shown in FIG. 7, the current of the coil 23b of the magnetic poles 22c and 22d is stopped, and the current is passed through the coil 23a on the side of the magnetic poles 22a and 22b so as to increase the magnetic force of the magnetic pole 22b. The magnetic pole 22 b attracts strongly with the convex pole 13, and the magnetic pole 22 a cancels the magnetic force and does not attract with the convex pole 11. The mover 20 moves to the right in the figure so that the magnetic pole 22b faces the convex pole 13.

(4) STEP 4: As shown in FIG. 7, the current of the coil 23a of the magnetic poles 22a and 22b is stopped, and the current is passed through the coil 23b on the magnetic poles 22c and 22d side so as to increase the magnetic force of the magnetic pole 22c. The magnetic pole 22 c attracts strongly with the convex pole 15, and the magnetic pole 22 d cancels the magnetic force and does not attract with the convex pole 16. The mover 20 moves to the right in the figure so that the magnetic pole 22c faces the convex pole 15.
In addition, after moving to the position of STEP4, as shown in STEP4 of FIG. 7, the moving element 20 can be held at the position of STEP4 by continuing to pass a current through the coil 23b.

  As shown in FIG. 8, when the distance between the convex poles formed on the platen 10 is a, the distance between the convex poles formed on the magnetic poles 22a to 22d is a, the magnetic pole 22a and the magnetic pole 22b, and the magnetic pole 22c and the magnetic pole 22d. The interval is 2a, and the interval between the magnetic pole 22b and the magnetic pole 22c is 2.5a. With this configuration, when the magnetic pole 22a and the magnetic pole 22b are opposed to the convex pole of the platen 20, as shown in FIG. 6, a part of the magnetic pole 22c and the magnetic pole 22d (1/2 in this example) Faces the convex pole of the platen 10.

FIG. 9 is a diagram showing a configuration when four moving elements 20a to 20d are provided on a moving body 30 such as a work stage so that they can move in the orthogonal X and Y directions. FIG. 9B is a diagram of the moving body 30 moving above as viewed from the surface facing the platen 10, and FIG. 9B shows the direction in which the moving body 30 is parallel to the plane of the platen 10, that is, P− in FIG. It is the figure seen from the P direction. In these drawings, the movable element 20 is shown as a continuum of convex poles, but actually has the configuration shown in FIGS. 6 and 8. In FIG. 9B, the convex pole provided on the platen 10 is omitted.
As shown in FIG. 9A, air pads 40 for blowing air are provided at the four corners of the moving body 30. The air blown from the air pad 40 hits the surface of the platen 10, and the moving body 30 floats with respect to the platen 10.

As illustrated in FIG. 9A, the movers 20 a to 20 d are provided at four locations in the XY direction orthogonal to the center of the moving body 30. The movers 20a and 20b are movers for moving the moving body 30 in the X direction (left and right direction in FIG. 9A), and are provided at two locations on the Y axis (up and down in the figure). The movers 20c and 20d are movers for moving the moving body 30 in the Y direction (the vertical direction in FIG. 9A), and are provided at two locations on the X axis (left and right in the figure).
In each of the movers 20a to 20d, a magnetic field for moving in the horizontal direction in the figure is generated at the magnetic poles of the movers 20a and 20b for moving in the X direction, and the moving directions of the magnetic fields in both the movers 20a and 20b are the same. If there is, the moving body 30 moves in the X direction. In addition, a magnetic field for moving in the vertical direction in the figure is generated at the magnetic poles of the movers 20c and 20d for moving in the Y direction. If the moving directions of the magnetic fields in both the movers 20c and 20d are the same, the moving body 30 is used. Moves in the Y direction.

When a stage having such a moving body 30 is used as a work stage of a sequential exposure apparatus, it is not sufficient to move only in the XY directions, and the stage is rotated around an axis perpendicular to the stage surface (such as this Is necessary to be referred to as θ rotation hereinafter).
In order to rotate the moving body 30 by θ, for example, the moving direction of the magnetic field of the moving body 20c and the moving body 20d of the moving body 30 is reversed. Then, since the moving direction is opposite between the moving element 20c side and the moving element 20d side of the moving body 30, the moving body 30 rotates θ. Even when the moving direction of the magnetic field of the moving element 20a and the moving element 20b is reversed, the moving body 30 can be similarly rotated by θ.

The planar stage shown above is used as a work stage of an exposure apparatus, for example. In that case, for example, a vacuum suction mechanism is provided on the moving body, a workpiece such as a wafer or a printed board is placed and held, and the moving body is sequentially moved to change the exposure position on the workpiece for exposure. Processing is performed.
As described above, when the planar stage is used as a work stage of the exposure apparatus, the moving body on which the work is placed must be moved accurately and accurately. For this purpose, the moving distance of the moving body must be measured by a sensor, and the moving distance of the moving body must be feedback controlled.

  There are various methods for measuring the moving distance of the moving body. However, the surface motor stage device (soya motor stage device) is non-contact because the moving body is air-floating with respect to the platen, and the sliding part is Since there is no low dust generation, a non-contact type sensor is used for measuring the moving distance. Conventionally, length measuring lasers have been used as such sensors.

10 and 11 show the configuration of a work stage (planar stage) in the case where a length measuring laser is used as a sensor for measuring the moving distance of a moving body. 10A is a perspective view of the work stage, FIG. 10B is a side view of the work stage, and FIG. 11 is a plan view of the swork stage shown in FIGS. 10A and 10B as viewed from above. . In FIG. 11, the workpiece is omitted, and the platen is omitted in FIGS. 10 (a), 10 (b) and FIG.
As shown in these drawings, the movable element 20 is attached to the lower surface of the movable body 30. A work holding stage 50 in which a vacuum suction groove 51 for sucking and holding a work 70 such as a wafer or a printed board is formed is attached to the upper part of the moving body 30. A plane mirror 61 is provided on the surface of the work holding stage 50 in the plane direction (XY both directions). Furthermore, a laser length measuring device 62 is fixedly provided at a reference position outside the flat stage (work stage), and a length measuring laser is emitted from the laser length measuring device 62 toward the flat mirror 61 of the work holding stage 50, The reflected light from the plane mirror 61 is incident on the laser length measuring device 62 and the distance is measured.
The laser length measuring device 62 measures the distance to the object based on a phase shift between the laser light emitted from the laser length measuring device 62 and the laser light reflected back from the object and incident again. Yes, generally available on the market. As the laser light source, a He—Ne laser is mainly used.

Control of the work stage corrects the error of the movement distance by measuring the movement distance in the X direction and the Y direction by the laser length measuring device 62 after the movement of the moving body 30 and feeding back the measured movement distance information. Is done.
Patent Document 3 discloses an exposure apparatus that includes a planar stage having the above-described configuration as a work stage. This document discloses a technique in which a mirror is attached to a work stage as described above, and laser light is emitted to the mirror from a position independent of the work stage to measure the length.
Japanese Patent Laid-Open No. 9-23689 JP 2006-149051 A JP-A-7-226354 JP 2006-194672 A

  However, the method using the length measuring laser 62 as described above has the following problems. The length of the flat mirror 61 provided on the work holding stage 50 needs to be increased by the stroke (movement distance) of the moving body 30. On the other hand, for example, in the case of a large-sized printed circuit board or liquid crystal panel, the workpiece to be exposed is larger than the wafer. When the workpiece is exposed by step and repeat, the workpiece holding stage 50 becomes large and the moving body 30 moves. The distance also becomes longer. Accordingly, when the plane mirror 61 is provided on the workpiece holding stage 50 of the apparatus that exposes a large workpiece by step and repeat, the plane mirror 61 becomes longer and heavier, and therefore the entire workpiece stage also becomes heavier. As the work stage becomes heavier, it becomes difficult to quickly move and position the work stage for step and repeat. In addition, a large moving mechanism and movement control device are required.

Although Patent Document 4 shows that a lightweight length measuring laser is provided on the moving body side, a mirror having a length corresponding to the stroke of the moving stage is required to reflect the length measuring laser. Thus, since the mirror surface is required to have high precision flatness, the manufacturing cost of the mirror is increased. Further, the laser for length measurement is slightly expensive both in the case of a He—Ne laser and in the case of the semiconductor laser described in Patent Document 4, leading to an increase in the cost of the apparatus.
As a non-contact type sensor, the electrostatic sensor is smaller and lighter than the laser length measuring device, so it is possible to use an electrostatic sensor. The problem is that a vessel is required and the structure is complicated.

An object of the present invention is to provide a magnetic sensor that is light and inexpensive and has a simple structure in order to measure the moving distance of a moving body.
Another object of the present invention is to provide a light and inexpensive magnetic flux sensor with a simple structure for measuring the moving distance of a moving body in a planar stage using a surface motor stage device (soya motor stage device). Is to provide a flat stage.

In order to solve the above problems, the present invention employs the following means.
The first means includes a magnetic body having a comb-like portion having a plurality of convex portions made of a magnetic material, magnetic flux generating means for generating a magnetic flux in the comb-like portion, and the comb-like portion. A magnetic flux sensor comprising: magnetic flux measuring means for measuring a change in magnetic flux and outputting the result.
The second means is a planar stage including a platen in which convex poles made of a magnetic material are formed at equal intervals, a moving body that floats and moves on the platen, and a control unit that controls the moving body. The moving body is formed with a comb-like portion made of a magnetic material and having a plurality of convex portions having a pitch that is an integral multiple of the pitch of the convex poles of the platen and having the same width as the width of the convex poles. A magnetic body, a magnetic flux generating means for generating a magnetic flux in the comb-like portion, and a magnetic flux measuring means for measuring a change in the magnetic flux of the comb-like portion and outputting the result, A magnetic flux sensor is provided in which a convex portion of a convex portion is arranged so as to face the platen, and the control unit calculates a moving distance of the moving body based on an output measured by the magnetic flux measuring means. Is a flat stage.
According to a third means, in the second means, two of the magnetic flux sensors are arranged in a direction in which the moving body moves, and a space between comb teeth of the two magnetic flux sensors is a convex pole of the platen. The flat stage is characterized by being separated by a distance that is not an integral multiple of the pitch.

According to the first aspect of the present invention, a lightweight and inexpensive magnetic flux sensor with a simple structure can be realized in order to measure the moving distance of the moving body.
According to the second aspect of the present invention, the measurement of the moving distance by the magnetic flux sensor is performed by using the convex pole of the platen formed to move the moving body of the planar stage. It is not necessary to provide a stage or a device for mounting a new part on the stage in response to the sensor for the sensor, and it is possible to prevent an increase in the number of components other than the magnetic flux sensor for distance measurement, and to reduce the weight of the flat stage. Cost reduction can be achieved.
According to the third aspect of the present invention, the movement distance can be accurately measured by the magnetic flux sensor.

An embodiment of the present invention will be described with reference to FIGS.
1A and 1B are diagrams showing a schematic configuration of a planar stage according to the invention of the present embodiment. FIG. 1A is a side view of the planar stage, and FIG. 1B is a plan view of the planar stage.
In these drawings, 1 is a planar stage, 2 is a moving body that moves on the platen 8, 3 is a moving element provided on the lower surface of the moving body 3 so as to face the platen 8, and 4 is a moving body with respect to the platen 8. 2 is an air blowing section provided for floating the air, 5 is a work holding stage for holding the work 10, 6 is a vacuum suction groove provided on the upper surface of the work holding stage 5 and provided for sucking and holding the work 10, 7 is a magnetic flux sensor for measuring the moving distance of the moving body 2 attached to both side surfaces of the moving body 2 in the X direction and the Y direction, 8 is a platen, and 9 is based on the output measured by the magnetic flux sensor 7. The control unit 10 that calculates the moving distance of the moving body 2 and feedback-controls the moving distance of the moving body 2 is a work.

  As shown in these drawings, the planar stage 1 is generally composed of a moving body 2 and a platen 8, and the moving distance of each direction of the moving body 2 in the X direction and the Y direction, which are the moving directions of the moving body 2. A magnetic flux sensor 7 is attached to measure. Further, the control unit 9 outputs a movement command signal for moving the moving body 2 by a predetermined distance to the moving body 2 to move the moving body 2. Further, the control unit 9 inputs an output signal from the magnetic flux sensor 7 attached to the moving body 2, calculates the moving distance of the moving body 2, and feedback-controls the movement of the moving body 2.

2 is an enlarged view of the configuration of the magnetic flux sensor 7 and the platen 8 attached to the moving body 2. FIG. 2 (a) is a side view thereof, and FIG. 2 (b) is a perspective view thereof. Note that the platen 8 shown in FIG. 2B shows the configuration of the platen in the case of uniaxial movement, and the platen in the case of biaxial movement is composed of lattice-like grooves.
In the figure, reference numerals 71 and 72 denote a first magnetic flux sensor and a second magnetic flux sensor, respectively, which constitute the magnetic flux sensor 7, reference numeral 11 denotes a comb-like portion made of a magnetic material such as iron, and reference numeral 12 denotes a permanent magnet. A magnetic flux generation unit that is composed of a magnet or an electromagnet and generates a magnetic flux in the comb-shaped portion 11, 13 is composed of a Hall element, and a magnetic flux measuring unit that measures the magnetic flux of the comb-shaped portion 11, and 14 is a comb-shaped A convex portion formed at the end of the portion 11, 15 is a convex pole formed on the upper surface of the platen 8, and 16 is a resin portion made of a nonmagnetic material formed between the convex poles 15.

  As shown in these drawings, each of the first and second magnetic flux sensors 71 and 72 is mainly composed of three parts, that is, a comb-shaped part 11, a magnetic flux generation part 12, and a magnetic flux measurement part 13. The comb-shaped portion 11 has a plurality of convex portions 14 having the same pitch as the pitch d of the convex poles 15 of the platen 8 and the same width as the width of the convex poles 15. The convex portion 14 is provided to face the convex pole 15 of the platen 8. The pitch of the convex portions 14 of the comb-like portion 11 may be an integral multiple (two times, three times,...) Of the pitch d of the convex poles 15 of the platen 8. The Hall element used in the magnetic flux measuring unit 13 is a sensor that converts a magnetic force into a voltage and outputs the voltage. When the magnetic force increases (the magnetic resistance decreases), the output voltage increases and the magnetic force decreases (the magnetic resistance decreases). Output voltage decreases. Such a Hall element is embedded in the magnetic path of the comb-like portion 11.

The magnetic flux sensor 7 is attached to the moving body 2 in one direction in which the moving body 2 moves, with the first and second magnetic flux sensors 71 and 72 as one set. That is, if the movable body 2 moves orthogonally in the X direction and the Y direction, they are attached in the X direction and the Y direction, respectively. Here, the number of magnetic flux sensors is considered as a single combination of a comb-shaped portion, a magnetic flux generating portion, and a magnetic flux measuring portion. Specifically, the number of magnetic flux measuring units, for example, Hall elements corresponds to the number of magnetic flux sensors. The distance D between the comb teeth 11 of the first and second magnetic flux sensors 71 and 72 is a distance shifted with respect to the pitch d of the convex poles 15 of the platen 8 and is an integer of the pitch of the convex poles 15 of the platen 8. Provided with a non-double interval. For example, as shown in FIG. 2A, D = 0.75 × d.
In order to move the moving body 2, the magnetic flux sensor 7 is located outside the moving body 2 at a position away from the moving body so as not to be affected by the magnetism of the moving body attached to the lower surface of the moving body 2. Provided. When the moving body 2 moves on the platen 8, the magnetic flux sensor 7 also moves on the platen 8.

Next, the principle of measuring the moving distance of the moving body 2 will be described.
FIGS. 3A and 3B are diagrams showing a change in the positional relationship between the convex portion 14 of the comb-tooth shaped portion 11 of the magnetic flux sensor 7 and the convex pole 15 of the platen 8 as the moving body 2 moves. .
In the drawing, only movement in one axis direction is shown, and when the moving body 2 moves in two axis directions, the magnetic flux sensor 7 is also provided in a direction orthogonal to this (the front and back direction in the drawing). .
As shown in these drawings, the magnetic flux sensor 7 is attached to the moving body 2 and moves on the platen 8 as the moving body 2 moves. The comb-teeth portion 11 of the magnetic flux sensor 7 is provided with a magnetic flux generator 12 to generate a magnetic flux. The comb-teeth portion 11 of the magnetic flux sensor 7 is simply provided with two convex portions 14, and the pitch thereof is twice the pitch of the convex poles 15 of the platen 8.

FIG. 3A shows a state in which the convex portion 14 of the comb-shaped portion 11 faces the convex pole 15 of the platen 8. At this time, the convex portion 14 of the comb-tooth-shaped portion 11 generating the magnetic flux attracts the convex pole 15 of the platen 8, and a strong magnetic force is generated between them. That is, the magnetic resistance in the magnetic path including the comb-shaped portion 11 and the platen 8 is reduced, the magnetic flux measured by the magnetic flux measuring unit 13 provided in the comb-shaped portion 11 is increased, and the output voltage is increased.
FIG. 3B shows a state in which the moving body 2 moves to the right in the drawing, and the convex portion 14 of the comb-like portion 11 faces the resin portion 16 of the platen 8. At this time, since the convex part 14 of the comb-tooth-shaped part 11 does not attract the resin part 16 which is not a magnetic body, the magnetic force between both becomes weak. That is, the magnetic resistance in the magnetic path including the comb-teeth part 11 and the platen 8 is increased, the magnetic flux measured by the magnetic flux measuring unit 13 provided in the comb-teeth part 11 is reduced, and the output voltage is reduced.

That is, the output voltage from the magnetic flux measuring unit 13 of the magnetic flux sensor 7 becomes maximum when the convex portion 14 of the comb-like portion 11 in FIG. 3A completely faces the convex pole 15 of the platen 8. When the convex part 14 of the comb-tooth shaped part 11 of 3 (b) completely opposes the resin part 16 of the platen 8, it becomes the minimum. Further, when the convex portion 14 of the comb-like portion 11 is located between the convex pole 15 of the platen 8 and the resin portion 16 (intermediate between FIG. 3A and FIG. 3B), it is output from the magnetic flux measuring portion 13. The output voltage is intermediate between the output in FIG. 3A and the output in FIG.
Therefore, if the output voltage from the magnetic flux measuring unit 13 of the magnetic flux sensor 7 is recorded and the moving body 2 moves from the position where the voltage is maximum to the position where the voltage is minimum, the movement distance of the platen 8 is That is, the distance is half the pitch of the convex poles 15. Similarly, if the moving body has moved from the maximum position to the position where it passes the minimum position and becomes the maximum again, the moving body 2 has moved by the pitch of the convex poles 15 of the platen 8. become.

Next, a change in the positional relationship between the convex portion 14 of the comb-like portion 11 of the moving magnetic flux sensor 7 and the convex pole 15 of the platen 8 will be specifically described with reference to FIG. Here, the platen 8 shows a case of biaxial movement, and the convex poles 15 are formed in a lattice shape.
4A is a side view of the magnetic flux sensor 7 that measures the magnetic flux in the X direction as viewed from the X direction, and FIG. 4B is a side view of the magnetic flux sensor 7 as viewed from the Y direction.
As shown in FIG. 4A, the pitch d1 between the convex poles 15 of the platen 8 is 5 mm, and the width w1 between the convex poles 15 and the resin portion 16 is 2.5 mm. On the other hand, the pitch d2 of the convex portions 14 of the comb-like portion 11 is 5 mm, which is the sum of the pitches of the convex poles 15 of the platen 8, and the width wx of the convex portion 14 of the comb-like portion 11 is the magnetic flux sensor 7. Is 2.5 mm which is the same as the width w1 of the convex pole 15 of the platen 8 with respect to the direction (X direction) for measuring the movement distance. Thus, it is essential to match the pitch d2 and the width wx of the convex portion 14 of the comb-tooth-shaped portion 11 with the pitch d1 and the width w1 of the convex pole 15 of the platen 8.
On the other hand, as shown in FIG. 4B, the width of the convex portion 14 of the comb-tooth shaped portion 11 is the platen in the direction (Y direction) orthogonal to the direction of measuring the movement distance (X direction). It is 5 mm (one pitch), which is the sum of the width of the eight convex poles 15 and the width of the resin portion 16. The reason is to prevent the output from the magnetic flux sensor 7 from changing when the moving body 2 moves in a direction in which the magnetic flux sensor 7 does not measure the movement distance.

Next, a description will be given of the movement distance measurement during a minute movement that does not pass through the maximum value and the minimum value of the output voltage output from the magnetic flux measurement unit 13 to the magnetic flux sensor 7.
FIG. 5 shows the magnetic flux measurement unit 13 provided in the first magnetic flux sensor 71 and the magnetic flux measurement unit 13 of the second magnetic flux sensor 72 in accordance with the movement of the magnetic flux sensor 7 accompanying the movement of the moving body 2 in FIG. It is a figure which shows the output voltage output from.
Here, the output voltage from the magnetic flux measuring unit 13 is, for example, 0 mm when the maximum value is +0.5 V, 1.25 mm when 0 V, and 2.5 mm when -0.5 V is the minimum value. By storing the position data for the output voltage from the magnetic flux measurement unit 13 in the control unit 9 of the planar stage 1, the position of the moving body 2 can be obtained based on the output voltage from the magnetic flux measurement unit 13. it can.

However, as can be seen from FIG. 5, if there is one magnetic flux sensor 7, for example, the position data when the output voltage from the magnetic flux measurement unit 13 is 0 V includes 1.25 mm and 3.75 mm. The position of the moving body 2 is not determined at one position with respect to the output voltage from the magnetic flux measuring unit 13.
Therefore, as shown in FIG. 2, the magnetic flux sensor 7 is provided with first and second magnetic flux sensors 71 and 72 in the uniaxial direction of the moving body 2. The distance D between the comb-teeth portions 11 of the two magnetic flux sensors 71 and 72 is shifted with respect to the pitch d of the convex poles 15 of the platen 8 and is not a multiple of the pitch of the convex poles 15 of the platen 8. Provide separately.
By configuring the magnetic flux sensor 7 in this way, a phase difference is generated in the output voltage output from the magnetic flux measuring unit 13 of the two magnetic flux sensors 71 and 72. If there is a phase difference between the output voltages of the magnetic flux measuring units 13 of the two magnetic flux sensors 71 and 72, the two output voltages are compared to determine one position.

For example, even if the output voltage from the magnetic flux measuring unit 13 of the first magnetic flux sensor 71 is 0 V, and there are two position data at that value, 1.25 mm and 3.75 mm, the second magnetic flux sensor 72. The output voltage from the magnetic flux measuring unit 13 is + 0.5V if the position data is 1.25 mm, and -0.5 V if the position data is 3.75 mm. Therefore, if the position data for the output voltages from the respective magnetic flux measuring units 13 of the first and second magnetic flux sensors 71 and 72 is stored in the control unit 9 of the planar stage 1 in advance, the position is determined as one location. can do.
As a result, when the output voltage from the magnetic flux measuring unit 13 of the first magnetic flux sensor 71 is 0V, if the output voltage from the magnetic flux measuring unit 13 of the second magnetic flux sensor 72 is positive, the position is 1.25 mm, When the output voltage of the magnetic flux measuring unit 13 of the first magnetic flux sensor 71 is 0V, if the output voltage from the magnetic flux measuring unit 13 of the second magnetic flux sensor 72 is negative, the position is 3.75 mm.

The control unit 9 of the planar stage 1 outputs a movement command signal for moving the moving body 2 by a predetermined distance, and moves the moving body 2. When the moving body 2 moves, the control unit 9 obtains the moving distance of the moving body 2 as described above based on the output signal from the magnetic flux sensor 7. Based on the obtained movement distance, the movement of the moving body 2 is feedback-controlled.
Although the movement in the X direction has been described above, the movement distance can be obtained in the same manner for the movement in the Y direction by the magnetic flux sensor 7 that measures the movement distance in the Y direction. At this time, as described above, the width of the convex portion 14 of the comb-shaped portion 11 of the magnetic flux sensor 7 that measures the movement distance in the X direction is the width of the convex pole 15 of the platen 8 and the resin portion 16 in the Y direction. Is added. Therefore, when the moving body 2 moves in the Y direction, the convex portion 14 of the comb-like portion 11 of the magnetic flux sensor 7 that measures the moving distance in the X direction always faces the convex pole 15 of the platen 8, so that the magnetic flux No change occurs and the output from the magnetic flux sensor 7 does not change.
With this configuration, for example, when the moving body 2 is moving in the Y direction, if the output from the magnetic flux sensor 7 that measures the moving distance in the X direction changes, the control unit 9 also moves in the X direction. This can be prevented because it may be detected erroneously.

  As described above, according to the embodiment of the present invention, the movement distance is measured by the magnetic flux sensor using the platen convex pole formed to move the moving body (moving element) of the planar stage. Yes. In other words, the platen is shared for the movement of the moving body (moving element) and the measurement of the moving distance. Therefore, it is not necessary to provide a stage or a device for mounting a new part on the stage in correspondence with the sensor for measuring the distance of the moving body. As described above, when a conventional side-length laser is used, a reflection mirror for reflecting the laser is required. However, according to the present invention, there is no need to newly provide a part corresponding to the mirror required in the side-long laser system. Therefore, it is possible to prevent the configuration other than the magnetic flux sensor from increasing for distance measurement, and to reduce the weight and cost of the planar stage.

It is a figure which shows schematic structure of the plane stage which concerns on this invention. It is the figure which expanded and showed the structure of the magnetic flux sensor 7 attached to the moving body 2, and the platen 8. FIG. It is a figure which shows the change of the positional relationship of the convex part 14 of the comb-tooth shaped part 11 of the magnetic flux sensor 7, and the convex pole 15 of the platen 8 with the movement of the mobile body 2. FIG. It is the figure which looked at the magnetic flux sensor 7 which measures the magnetic flux of a X direction from the X direction and the Y direction. In FIG. 2, the magnetic flux measurement unit 13 provided in the first magnetic flux sensor 71 and the magnetic flux measurement unit 13 of the second magnetic flux sensor 72 output from the magnetic flux sensor 7 as the moving body 2 moves. It is a figure which shows an output voltage. It is sectional drawing which shows the platen 10 which has the some convex pole which comprises a planar stage, and the slider 20 which has a magnetic pole. 3 is a timing chart of currents flowing through a coil wound around a magnetic pole of a mover 20. 3 is a diagram illustrating a configuration of magnetic poles of a mover 20. It is a figure which shows the structure at the time of providing the four moving elements 20a-20d in the moving bodies 30, such as a work stage, so that it can move to the XY direction which orthogonally crosses. It is the perspective view and side view which show the structure of the work stage (planar stage) at the time of using the laser for length measurement as a sensor which measures the moving distance of a moving body. It is a top view which shows the structure of the work stage (plane stage) at the time of using the laser for length measurement as a sensor which measures the moving distance of a moving body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Planar stage 2 Moving body 3 Mover 4 Air blowing part 5 Work holding stage 6 Vacuum adsorption groove 7 Magnetic flux sensor 71 First magnetic flux sensor 72 Second magnetic flux sensor 8 Platen 9 Control part 10 Work 11 Comb-shaped part 12 Magnetic flux Generating part 13 Magnetic flux measuring part 14 Convex part 15 formed at the end of the comb-like part 11 Convex pole 16 formed on the upper surface of the platen 8 Resin part formed between the convex poles 15

Claims (3)

A magnetic body formed with a comb-like portion having a plurality of convex portions made of a magnetic body;
Magnetic flux generating means for generating magnetic flux in the comb-tooth-shaped portion;
Magnetic flux measuring means for measuring a change in magnetic flux of the comb-like portion and outputting the result;
A magnetic flux sensor comprising: In a planar stage including a platen in which convex poles made of a magnetic material are formed at equal intervals, a moving body that floats and moves on the platen, and a control unit that controls the moving body.
In the moving body,
A magnetic body made of a magnetic material, having a pitch that is an integral multiple of the pitch of the convex poles of the platen, and having a plurality of convex portions having the same width as the width of the convex poles; A magnetic flux generating means for generating a magnetic flux in the comb-tooth-shaped portion, and a magnetic flux measuring means for measuring a change in the magnetic flux of the comb-tooth-shaped portion and outputting the result, A magnetic flux sensor arranged to face the platen is provided,
The planar stage characterized in that the control unit calculates a moving distance of the moving body based on an output measured by the magnetic flux measuring means. Two of the magnetic flux sensors are arranged in the direction in which the moving body moves, and the comb teeth of the two magnetic flux sensors are separated by a distance that is not an integral multiple of the pitch of the convex poles of the platen. The planar stage according to claim 2, wherein

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