JP2716884B2 - Flat motor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar motor, and more particularly, to a planar motor capable of driving a stage member on which an object is mounted within a relatively wide surface with high precision.

[0002]

2. Description of the Related Art In the field of ultra-precision machinery such as a semiconductor manufacturing apparatus, there is a demand for an apparatus which drives an object within a relatively wide plane to perform positioning, thereby improving positioning accuracy.

Conventionally, as an apparatus for two-dimensionally driving an object, first, an x-stage provided with a servomotor for driving in the x-axis direction, which is one direction in a plane, and a ball screw is formed. An xy stage and the like in which a servo motor for driving in the y-axis direction and a y stage provided with a ball screw and the like are superposed are known. According to the xy stage having such a configuration, a power transmission mechanism and a guide mechanism are necessary, and 100% of the power of the driving source is not transmitted to the object, and unnecessary distortion and elasticity of the mechanical members constituting the stage are required. Causing deformation. In addition, the combination of the two stages increases the overall size, and as a result, when performing high-speed motion, the influence of vibration is likely to occur and the accuracy is likely to deteriorate.

Therefore, it is difficult to achieve a high positioning accuracy of about 0.01 μm or less. In general, in order to reduce the amount of elastic deformation or reduce the influence of vibration, the rigidity is generally increased by increasing the size of the mechanical structure.

In the case of such a configuration, the stage device for realizing high-precision positioning becomes large and the weight increases.

[0006]

As described above,
With an xy stage or the like according to a conventional technique, it has been difficult to realize an ultra-precision stage device having a positioning accuracy of, for example, 0.01 μm.

An object of the present invention is to provide a planar motor device as a drive system suitable for realizing, for example, a small and ultra-precise precision stage device.

[0008]

A planar motor device according to the present invention is a planar motor device for moving a stage member for mounting an object in a predetermined plane relative to a reference support member. A combination of a plurality of permanent magnets attached to one of the stage member and the support member and generating a magnetic flux in a direction substantially perpendicular to the predetermined surface, and a yoke connecting the permanent magnets; , The compound
Each of the plurality of permanent magnets comprises the stage member and the support member.
A plurality of permanent magnets having the same magnetic pole on the entire surface facing the other side, wherein the plurality of permanent magnets have a shape elongated in a first direction in the predetermined surface; And a second permanent magnet having a shape elongated in a second direction in the predetermined plane perpendicular to the predetermined plane, wherein the yoke fixes a relative position between the plurality of permanent magnets, and the stage member And the other of the support members,
A plurality of sets of coils including a set of coils and a set of second coils, wherein each coil of the first set of coils has a coil axis in the second direction and the first direction. Arranged in
At least some of the coils are engaged with the magnetic field by the first permanent magnet, and each coil of the second set of coils is
, And arranged in the second direction, at least a part of the coils is engaged with the magnetic field by the first permanent magnet, and the first coil set and the second coil And a plurality of sets of coils whose relative positions with respect to the set are fixed.

[0009]

According to the present invention, since an integral permanent magnet is arranged opposite to a plurality of coils, even if the relative position between the coil and the permanent magnet is displaced, a force is continuously applied by flowing current to the plurality of coils. Can be generated.

Since the generated force acts directly between the coil and the permanent magnet attached to the stage member and the support member, play and elastic deformation can be reduced.

[0011]

FIG. 1 is a schematic view of a planar motor device according to an embodiment of the present invention. FIG. 1A is a plan view showing a positional relationship between a coil and a permanent magnet. FIG. 1B is a schematic side view showing the positional relationship between the permanent magnet and the coil.

As shown in FIG. 1A, an x-axis direction, a y-axis direction, and a rotation direction θ direction about an axis perpendicular to the x-axis and the y-axis are set in the movable plane of the planar motor.

The planar motor device has, as basic units, a linear motor structure 13 in the x direction and linear motor structures 14 and 15 in the y direction. x direction linear motor structure 1
3, four equivalent x coils 9a1, 9a
2, 9a3, 9a4 are arranged side by side in the y-axis direction, are separated by a predetermined distance in the x-axis direction, and have another four equivalent x coils 9
b1, 9b2, 9b3, 9b4 are arranged side by side in the y-axis direction.

Further, two corresponding x coils 9a
A common high magnetic permeability core 12 is arranged so as to penetrate through 1 and 9b1. Similarly, the corresponding x coils 9a2 and 9b
2, 9a3 and 9b3, and 9a4 and 9b4, respectively, and the core 12 is arranged so as to pass therethrough.

In the illustrated arrangement, one x magnet 6a long in the y direction is arranged so as to face three x coils 9a1, 9a2, 9a3 arranged on the lower side in the figure.
Opposite to the other three x coils 9b1, 9b2, 9b3, another x magnet 6b long in the y direction is arranged.

The same configuration is adopted in the y-direction linear motor structures 14, 15. That is, in the y-direction linear motor structure 14, the y coil 10b
1, 10b2, 10b3, 10b4 are arranged side by side in the x-axis direction, and the other y coils 10a1, 10a2, 10a3, 10
a4 are similarly arranged in the x-axis direction.

The y coils 10b1 and 10a1, 10b2 and 10a2 and 10b3 are disposed vertically.
10a3, 10b4 and 10a4 each have a core 12
Are arranged to penetrate.

The y permanent magnet 7b which is long in the x-axis direction
Is a y coil 10b that is long in the x direction in the arrangement in the figure
1, 10b2, 10b3, and the other y magnets 7a long in the x direction are y magnets 10a1, 10a2, 1
0a3 is arranged to face.

The other y-direction linear motor structure 15 is
It has the same configuration as the directional linear motor structure 14. That is, 11a1 to 11a4 and 11b1 to 11b4 are y
8a and 8b indicate y magnets, and 12 indicates a core.

FIG. 1B shows the x coils 9a1 and 9b1.
FIG. 5 is a schematic side view showing a relative relationship between x magnets 6a and 6b arranged thereon.

On the base 1, the x coils 9a1 and 9b1
Are fixed, and the core 12 is penetrated on the axis thereof. X is opposed to these x coils 9a1 and 9b1.
Magnets 6a and 6b are arranged via a gap 17. These x magnets 6a and 6b are fixed to the yoke 5, and the yoke 5 is fixed to the lower surface of the stage member 3. At least the yoke 5 is formed of a material having high magnetic permeability.

The pair of x magnets 6 a and 6 b are arranged with the polarity inverted with respect to the yoke 5. In the illustrated configuration, one x magnet 6a has an N pole below and an S pole above, and the other x magnet 6b has an N pole above and an S pole below.

Accordingly, the magnetic path 16 is formed as shown by the broken arrow in the figure, and the magnetic flux is distributed. In the presence of such a magnetic flux, when a current in the direction shown in the figure is applied to the coil 9a1 and a current in the opposite direction as shown in the figure is applied to the coil 9b1, the current mainly flowing in the upper part of the coil becomes the magnetic flux. Interacts with. Since the directions of the magnetic fluxes in these two coils are opposite to each other, a force in the same direction x is generated in both the coils that flow currents in opposite directions. This force drives the stage member 3 in the x direction.

According to the same principle, a y-direction force is generated in the y-direction linear motor structures 14, 15.

For example, the y-direction linear motor structure 1
The stage member 3 is displaced in the y direction by the forces generated at 4 and 15. At this time, although the coils facing the x magnets 6a and 6b are changed, some coils are changed to the x magnets 6a and 6b.
6b. Therefore, a force in the x direction can be generated.

FIG. 2 shows a driving mode of the planar motor device having the structure as shown in FIG. 2A shows the x translation mode, FIG. 2B shows the y translation mode, and FIG. 2C shows the θ rotation mode.

In FIG. 2A, a current is applied to the coil of the x-direction linear motor structure 13. For this reason, a force in the x direction is generated in the coil of the x-direction linear motor structure 13, and the stage member is driven in the x direction.

FIG. 2B shows the y translation mode. An electric current is applied to the coils of the y-direction linear motor structures 14, 15 so that a force in the same direction is generated. Then, the same y-direction driving force is generated in the coils of the y-direction linear motor structures 14 and 15. Therefore, the stage member translates in the y direction.

FIG. 2C shows the θ rotation mode in the xy plane. An electric current is supplied to the y-direction linear motor structures 14 and 15 so that a force in the opposite y-direction is generated. For example, current is supplied to each coil such that a force is generated in the −y direction in the y-direction linear motor structure 14 and in a + y direction in the y-direction linear motor structure 15 as shown in the drawing. When these parallel forces are generated in the opposite directions, the stage members supporting the permanent magnets of the linear motor structures 14, 15 rotate in the + θ direction in the xy plane.

In the above description, it has been assumed that each coil is fixed to the base, each permanent magnet is fixed to the stage member, and the stage can move freely in the xy plane. The force acting on the coil and the force acting on the permanent magnet are equal in magnitude and opposite in direction. Such a structure can be realized by, for example, supporting the stage in a xy plane with a roller or the like, but it is more preferable to use a bearing mechanism with low friction such as an air bearing as described below.

According to the structure in which the air bearing is combined so that the floating force of the air bearing acts in the opposite direction to the self-weight of the mechanical structure of the movable portion of the stage or the attraction force of a magnet or the like, the stage can be set at a predetermined height above the base. Hold on to
The robot can be freely moved in the xy plane.

FIG. 3 is a perspective view showing an xy stage device provided with a planar motor device. The base 1 has a flat guide surface 2 thereon, and the x coil 9 on the guide surface 2,
The y coil 10 and the second y coil 11 are fixed.

The x coil 9 has five coils arranged coaxially in the x-axis direction.
They are arranged in parallel in the set y direction. Moreover, the coil 1 for y
0 and 11 have five coils coaxially arranged in the y-axis direction,
Four sets of these five coils are arranged in the x direction. Note that a core having high magnetic permeability such as iron is inserted into the center of the coils arranged coaxially.

On the guide surface 2 of the base 1, an air pad 4
The main stage 3 supported by is arranged. The air pad 4 has, for example, an air outlet on its lower surface, and floats on the guide surface 2 of the base 1 by blowing air. When a vertical stage such as an SOR aligner is used, a plane motion can be performed on a vertical plane by using a permanent magnet in parallel with the air pad.

A yoke 5 made of a material having high magnetic permeability such as iron is fixed to the lower surface of the main stage 3. An x magnet 6 and y magnets 7 and 8 are further fixed to the lower surface of the yoke 5. Each magnet has a length that spans a plurality of corresponding coils.

FIG. 4 shows the relationship between the magnet and the coil in FIG. 3 in more detail. FIG. 4A is a diagram in which only one phase of the combination of the magnet and the coil is extracted. Permanent magnets M1 and M2 having an antiparallel relationship are fixed to the lower surface of the yoke 5. The interval between the permanent magnets M1 and M2 is set equal to the interval between the corresponding coils C1 and C2.

As shown, when the permanent magnets M1 and M2 are placed on the coils C1 and C2, the permanent magnets M1 reach the core 12 in the coil C1 and pass through the core 12 to the permanent magnet M2. A magnetic path returning to the permanent magnet M1 via the yoke 5 is formed. The upper windings of the coils C1, C2 intersect this magnetic path.

Therefore, when a current flows through the coils C1 and C2, a force corresponding to the strength of the current is generated in the axial direction of the coil.

However, in the coils C1 and C2, the magnetic flux proceeds in the opposite directions. Therefore, if forces in the same direction are generated in the coils C1 and C2, these forces act in opposite directions.
cancel. If currents in opposite directions are passed through the coils C1 and C2,
Forces in the same direction are generated.

By passing a current through the coil, the yoke 5
Moves in the direction of the arrow. However, magnets M1 and M2
Is moved over the boundary between the coils, a force in the opposite direction is generated from the adjacent coil, so that the force acting on the yoke 5 is reduced. The generation of such a force is shown in FIG.

That is, when one magnetic path is formed between the magnet and the coil and one-phase driving is performed, the generated force is as shown in FIG.
It becomes a ripple shape as shown in FIG.

In the stage apparatus shown in FIG. 3, each linear motor structure has four permanent magnets. As shown in FIG. 4B, these permanent magnets are grouped two by two, and the two groups are arranged out of phase.

That is, as shown, when the magnets M1 and M2 are on the boundary between coils and cannot generate a force,
The other magnets M3 and M4 are located above the coils C4 and C5 and can generate sufficient force. When the yoke 5 moves and the magnets M3 and M4 are positioned on the coil-coil boundary, the magnets M1 and M2 are now positioned on the center of the coil and generate sufficient force. FIG. 5B shows a pattern of a force generated by such two-phase driving.

That is, by synthesizing the two-phase driving forces with the phases shifted in the upper two stages shown in FIG.
(B) An almost constant thrust as shown at the bottom can be obtained.

Each magnet has a shape that is long in the lateral direction of the corresponding coil. FIG. 4C shows the relationship between the lateral direction of such a magnet and the coil. Coil C1, C6, C7, C
8 are arranged side by side in the horizontal direction. On the other hand, the magnet M1 has a width of three coils. Therefore,
Even when the yoke 5 moves in the lateral direction of the coil, the magnet and the coil face each other for a sufficient length, and a necessary force can be generated.

That is, in order to drive the stage over a wide range within a plane, it is not preferable to have one magnet opposed to one coil, and a plurality of coils are connected in the axial direction as shown in the figure. It is preferable to arrange a plurality of sets of coils in a direction perpendicular to the axis.

As described above, by arranging a large number of coils and arranging a large number of, for example, four magnets thereon to perform two-phase driving, the magnetic flux generated by the magnets is sufficiently linked to the coils. The force required for driving the stage can be generated in a sufficiently wide range.

It will be apparent to those skilled in the art that various driving modes as shown in FIG. 2 can be realized by controlling the current flowing through the coil facing the magnet.

The stage is lifted by an air pad and driven by a combination of a coil and a magnet.
A force can be directly applied to the stage with almost no friction. For this reason, it is possible to prevent the structural member from being distorted or elastically deformed. Further, the size of the entire apparatus can be reduced. In this way, a stage device capable of high-accuracy positioning is provided.

The present invention has been described in connection with the preferred embodiments.
The present invention is not limited to these. For example,
It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

[0051]

As described above, according to the present invention,
By arranging a large number of magnets in opposition to a large number of coils and supplying a controlled current to the coils, it is possible to control the force generated in the coils with high accuracy.

By controlling the thrust generated in the coil with high accuracy, high-precision positioning becomes possible.

As compared with a fine movement stage using a piezoelectric element or the like,
Large stroke drive is possible. In addition, high-precision positioning equivalent to that of the fine movement stage is possible.

If the coil is arranged on the base, heat generated by energization of the coil occurs in a state separated from the stage, so that heating of the main stage can be prevented.

[Brief description of the drawings]

FIG. 1 shows a planar motor device according to an embodiment of the present invention.
FIG. 1A is a plan view, and FIG. 1B is a side view.

FIG. 2 is a diagram for explaining a drive mode. FIG.
2A shows the x translation mode, FIG. 2B shows the y translation mode, and FIG. 2C shows the θ rotation mode.

FIG. 3 is a perspective view illustrating a stage device according to an embodiment of the present invention.

FIG. 4 is a schematic side view for explaining the principle of generation of a thrust of the stage device shown in FIG. 3; FIG. 4A shows one-phase driving, FIG. 4B shows two-phase driving, and FIG. 4C shows the arrangement of magnets in the lateral direction of the coil.

FIG. 5 is a graph for explaining a force generated corresponding to FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 2 Guide surface 3 Stage member (main stage) 4 Air pad 5 Yoke 6 Magnet for x 7, 8 y Magnet 9 Coil for x 10, 11 Y coil 12 Core

Claims (4)

(57) [Claims] 1. A planar motor device for moving a stage member for mounting an object on a predetermined surface relative to a reference support member, wherein one of the stage member and the support member And a combination of a plurality of permanent magnets that generate magnetic flux in a direction substantially perpendicular to the predetermined surface and a yoke that couples these permanent magnets, wherein each of the plurality of permanent magnets
Is the entire surface facing the other of the stage member and the support member
The body has the same magnetic pole, and the plurality of permanent magnets have a shape elongated in a first direction in the predetermined plane.
And a second permanent magnet having a shape elongated in a second direction in the predetermined plane orthogonal to the first direction, wherein the yoke is positioned relative to each of the plurality of permanent magnets. And a plurality of sets of coils including a first set of coils and a second set of coils attached to the other of the stage member and the support member, wherein the first set of coils Have a coil axis in the second direction and are arranged in the first direction, and at least some of the coils are engaged with a magnetic field by the first permanent magnet. , Each coil of the set has a coil axis in the first direction and is arranged in the second direction, and at least some of the coils engage a magnetic field provided by the first permanent magnet. Wherein the relative position between the set of coils and the set of second coils is fixed. A planar motor device including a plurality of sets of coils. 2. Each of the plurality of sets of coils has a plurality of cores arranged in parallel and a coil arranged at a plurality of corresponding positions of each core, and is provided at different positions in the axial direction of the cores. 2. The planar motor device according to claim 1, wherein the planar motor device is adapted to be driven in multiple phases. 3. The flat motor device according to claim 1, wherein the stage member and the support member are connected via a flat guide mechanism. 4. The plurality of sets of coils are a plurality of sets of cored coils having a core made of a material having high magnetic permeability on a shaft.
4. The flat motor device according to any one of claims 1 to 3.