JP2879934B2 - Stage equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a stage device, and more particularly, to a stage device for moving an object in a two-dimensional plane.

[Prior Art] Conventionally, as an apparatus for two-dimensionally driving an object, first, an X stage having a servomotor and a hole screw for driving in an X-axis direction which is one direction in a plane is formed.
An XY stage or the like in which a servomotor for driving in the Y-axis direction and a Y stage provided with a ball screw are superposed thereon is known.

Ball screws cannot completely eliminate backlash or backlash. Further, in order to transmit the driving force generated by the servomotor to the object, the driving force must be transmitted through a power transmission mechanism or a guide mechanism on the way, and the generated driving force cannot be transmitted 100% to the object. From another point of view, this means that some mechanical member or the like is distorted and elastically deformed.

With such a mechanism, it is difficult to achieve a positioning accuracy of about 0.01 μm or less.

[Problems to be Solved by the Invention] It has been difficult to realize an ultra-precise XY stage of, for example, 0.01 μm or less, with the stage device using the servo motor and the ball screw as described above.

An object of the present invention is to provide a stage device suitable for achieving ultra-precision accuracy.

It is another object of the present invention to provide a stage device having a simple structure, no play, and excellent position accuracy.

[Means for Solving the Problems] A plurality of stripe-shaped permanent magnets are arranged on a base member while alternately reversing their polarities. A plurality of first coils wound around an axis parallel to the stripe-shaped permanent magnet are fixed to the stage. A plurality of second coils wound around the axis are fixed to the stage with the direction intersecting the first coil as the axis. The lines of magnetic force generated from the striped permanent magnets are arranged so that the lower side of the first and second coils has a higher density than the upper side.

[Operation] Since the striped permanent magnets are arranged in parallel, the lines of magnetic force generated from the permanent magnets draw an arc in space and reach the adjacent permanent magnets. When a part of the coil intersects with the magnetic field lines, a force is generated in a direction perpendicular to the direction of current flow and the direction of the magnetic field lines. If the force generated in the rest of the coil is sufficiently small, a force in a predetermined direction can be applied to the coil. Since the winding directions of the first coil and the second coil are different, it is possible to generate forces along two directions in a plane. In this way, a stage device that can be driven two-dimensionally is realized.

Embodiment FIG. 1 is a perspective view showing a stage device according to an embodiment of the present invention.

The yoke 1 made of a material having high magnetic permeability, such as iron, is supported on the guide surface 4 by using a guide mechanism such as a sliding guide and a rolling guide. On the yoke 1, a plurality of elongated stripe-shaped permanent magnets 2 are arranged in parallel. In the figure, the permanent magnet 2 has magnetic poles on the upper surface and the lower surface, and the adjacent permanent magnets alternately reverse the magnetic poles. That is, looking at the magnetic poles on the upper surface of the permanent magnet, N poles, S poles, N poles, S poles... Are alternately arranged. The yoke 1 is driven by a magnet driving motor 3 in a direction perpendicular to the length direction of the permanent magnet. The yoke 1 has a guide mechanism for moving on the guide surface 4 in the Y direction. This guidance can be realized by various methods such as sliding guidance and rolling guidance. Guideway 4
A main stage 7 is supported via an air pad 8. On the lower surface of the main stage 7, a plurality of X coils 5 are arranged at the same pitch as the permanent magnets 2 on the yoke 1. On the lower surface of the main stage 7, a plurality of Y coils 6 are arranged in a direction orthogonal to the X coils. The Y coils 6 are also arranged at the same pitch as the permanent magnet 2.

The driving principle of the X and Y coils will be described with reference to FIGS. 2 (A) and 2 (B). For simplicity, one turn of each coil is taken out and illustrated.

FIG. 2 (A) shows one turn of the X coil. The permanent magnet 2 has an N pole on the upper surface and an S pole on the lower surface, and the magnetic lines of force emitted from the N pole are directed upward and terminate in adjacent permanent magnets of the opposite polarity. As shown in the figure, it is assumed that the X coil is disposed immediately above the permanent magnet 2. It is assumed that a current shown by an arrow flows through the coil 5. Then, a force F as shown by an arrow acts on the lower side of the coil 5 by Lorentz force. No force acts while the vertical side of the coil 5 is parallel to the line of magnetic force. When the lines of magnetic force are bent, forces in opposite directions are generated on the left and right, but these forces cancel each other out by using a plurality of X coils 5. A force opposite to that of the lower side acts on the upper side of the coil 5, but its absolute value is small. That is, a force acts on the X coil in the X direction, which is the length direction of the striped permanent magnet.

FIG. 2 (B) shows one turn of the Y coil. The coil for Y is wound in a plane orthogonal to the coil for X. Magnetic lines of force similar to those described above are generated from the permanent magnet 2. When a current as indicated by an arrow is applied to the Y coil 6, Lorentz force is generated in a direction perpendicular to the plane of the drawing. In the case shown in the drawing, a force F is applied to the coil 6 from the back side to the front side.

FIG. 3 is a schematic cross-sectional view for explaining the driving of a two-dimensional stage having both the X coil and the Y coil as shown in FIGS. 2 (A) and 2 (B). In the figure, on the yoke 1, elongated striped permanent magnets 2a, 2b,... 2f are arranged in parallel to the paper surface in the vertical direction. The magnetic poles exposed on the surface are arranged so that N and S are alternately repeated. Therefore, the magnetic field lines emanating from the north pole
Terminate at the pole. In the figure, X coils 5a, 5b, 5c, 5d are arranged on permanent magnets 2a, 2b, 2e, 2f. The X coils 6a and 6b are arranged on the central permanent magnets 2c and 2d. A counterclockwise current is applied to the X coils 5a and 5c as indicated by arrows in the figure, and a clockwise current is applied to the X coils 5b and 5d as indicated by arrows. Since the lines of magnetic force on the permanent magnet 2a are upward and the lines of magnetic force on the permanent magnet 2b are downward, the forces acting when the current direction is reversed are in the same direction. In the case shown in the drawing, a force is generated from the back surface to the front surface. Similarly, a force from the back surface to the front surface acts on the X coils 5c and 5d.

When driving in the Y direction, a current flowing in the Y direction is generated by flowing currents in opposite directions through the Y coils 6a and 6b as shown by the arrows in the figure.

It will be apparent to those skilled in the art that reversing the direction of each current will produce a force in the opposite direction.

FIG. 4 is a plan view illustrating a movement mode of the stage. In FIG. 4A, a current is applied to each of the Y coils in a direction in which a force in the + Y direction is generated. Since each Y coil generates a force in the + Y direction, the entire stage translates in the Y direction.

In FIG. 4 (B), a current is supplied to each X coil in a direction in which a force in the −X direction is generated. Therefore, each X
A force in the -X direction is generated in the use coil. Therefore, the entire stage translates in the −X direction.

In FIG. 4 (C), a current in a direction in which a force in the + X direction is generated is applied to the two right X coils,
A current in a direction in which a force in the −X direction is generated is applied to the two X coils. Accordingly, as a whole, the stage exerts a downward force on the right side and an upward force on the left side, and performs a rotational movement in the XY plane.

Thus, by exciting each coil in a desired direction, translation and rotation in the XY plane can be arbitrarily performed.

FIG. 5 is a partially enlarged view of the air pad shown in FIG. The air pad 8 has a duct for ejecting a gas such as air at the center, and a ring-shaped magnet 9 for exerting a magnetic attraction in a peripheral portion. The guide surface 4 is formed of a magnetic material such as iron. In the case where air of a constant pressure is jetted from the air pad, if the gap between the air pad 8 and the guide surface 4 is narrowed, the pushing force of the air is increased and the pad is pushed up. As the gap increases, the resistance to air flow decreases and the pad is attracted by the attractive force of the magnet. That is, the air pad sucks the stage 7 shown in FIG. 1 against the guide surface 4 and keeps the distance constant. Stage 7 has little resistance to its in-plane movement. When the X coil 5 and the Y coil 6 exert a force in a magnetic field and exert a driving force in parallel along the guide surface, the stage 7 moves along the surface direction according to the driving force. At this time, since the air pad shows almost no frictional force, the stage 7 is prevented from being distorted by the frictional force.

FIG. 6 shows a vertical stage for SOR exposure. Base 2
A duct 21 through which the SOR light 15 travels is formed in 0, and a window is formed.
SOR light is supplied through 23. Another base 25 is formed so as to face the base 20, and a yoke 24 having a guide surface is arranged thereon. A plurality of stripe-like magnets 2 are arranged on the yoke 24 in a direction perpendicular to the paper surface. The X coil 5 is opposed to the permanent magnet 2.
And a stage 7 on which a Y coil 6 is arranged is held by an air pad 8. Air pad 8 is base 20
Is attracted by magnetic force. A wafer chuck 11 is mounted on the left side of the stage 7 and holds a semiconductor wafer 12. The stage 7 is driven by the X coil 5 and the Y coil 6 and moves to a desired position while being supported by the air pad 8. Although not shown, the yoke 24 has a mechanism for finely moving the base 25 in the vertical direction in the figure.

In the embodiment described above, any drive can be performed in the X direction.
The driving force is weakened as the use coil 6 shifts from above the permanent magnet 2. That is, driving in the Y direction involves ripple-like vibration.

FIG. 7 shows another embodiment capable of reducing the ripple of the force in the Y direction.

FIG. 7A shows a plan view. A plurality of elongated permanent magnets 2 are arranged in parallel. Two X coils 5a and 5b are arranged on the left side and two X coils 5c and 5d are arranged on the right side, and three permanent magnets 2c, 2d and 2e are exposed at the center. For the three permanent magnets in the center, the Y coil 6a,
6b is arranged to face the permanent magnets 2d and 2e,
The two Y coils 6c, 6d are arranged in the middle of the permanent magnet. That is, as shown in FIG.
When the Y coils 6a and 6b are arranged on d and 2e,
The coils for use 6c and 6d are arranged between the permanent magnets 2c and 2d and between the permanent magnets 2d and 2e, as shown in FIG. 7 (C).
However, when the entire stage moves in the Y direction, the Y coils 6a and 6b gradually move away from above the permanent magnets and are moved to a position between the permanent magnets. At this time, the other Y coils 6c and 6d move from the intermediate region between the permanent magnet and the permanent magnet to above the permanent magnet. In this way, when the coils 6a and 6b lose power, the other coils 6c and 6d exhibit power and reduce ripple.

By incorporating a stage having a coil for Y as shown in FIG. 7 into the stage device shown in FIG. 1,
A stage device with reduced ripple components can be obtained. Similarly, a Y coil as shown in FIG. 7 can be used for a vertical stage for SOR exposure as shown in FIG.

Although the present invention has been described along with a limited embodiment,
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.

For example, the number of permanent magnets and coils can be arbitrarily changed. Further, the main stage may be held in a form other than the air pad.

The driving coil is not limited to the coreless type, and may be a cored type. The winding shape of the coil is not limited to the illustrated one.

[Effects of the Invention] As described above, according to the present invention, the stage can be driven by directly applying forces in the X and Y directions to the stage.

By eliminating the power transmission system, high motion accuracy can be realized.

X, Y, and θz torques can be directly applied to the stage, and position and orientation can be controlled.

Since the configuration is simple, a small and lightweight stage device can be provided.

 Because it is lightweight, it is advantageous for speeding up.

[Brief description of the drawings]

FIG. 1 is a perspective view of a stage device according to an embodiment of the present invention. FIGS. 2A and 2B are views for explaining the principle of driving the X and Y coils of the stage device shown in FIG. Conceptual diagram, FIG. 3 is a conceptual diagram for explaining driving of a two-dimensional stage having an X coil and a Y coil, and FIGS. 4A, 4B, and 4C are movement modes of an XY stage. FIG. 5 is a schematic cross-sectional view for explaining the function of the air pad, FIG. 6 is a cross-sectional view for explaining a vertical stage for SOR exposure, FIG. 4B and 4C are a plan view and a partial cross-sectional view illustrating another embodiment of the present invention. In the drawing, 1... Yoke 2... Permanent magnet 3... Drive motor 4... Guide surface 5... X coil 6... Y coil 7... Main stage 8. 11 Wafer chuck 12 Wafer 15 SOR light 20, 25 Base 21 SOR light duct 23 Window 24 Yoke

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-52-54108 (JP, A) JP-A-3-178746 (JP, A) JP-A-3-178747 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) H02K 41/02 H02K 41/03

Claims (5)

(57) [Claims] A base member having a first surface providing physical support and also serving as a yoke; and a first direction extending parallel to and on the first surface of the base member and adjacent to each other. A plurality of striped permanent magnets arranged, each striped permanent magnet having a magnetic pole along a direction normal to a first surface of the base member;
Magnetic poles of adjacent striped permanent magnets are inverted striped permanent magnets; a stage having a second surface facing the first surface of the base member; fixed on a second surface of the stage; A plurality of first coils wound around an axis parallel to a first direction of the stripe-shaped permanent magnet, wherein the absolute value of a force acting on a coil side close to the stripe-shaped permanent magnet and a coil side distant from the coil side; A plurality of first coils having sufficiently different absolute values of the acting force, fixed on a second surface of the stage, and having an axis along a second direction intersecting the first direction in the second surface; A plurality of second coils wound around the plurality of second coils, wherein the absolute value of the force acting on the coil side close to the striped permanent magnet and the absolute value of the force acting on the far coil side are sufficiently different from each other. Stage equipment. 2. The stage apparatus according to claim 1, further comprising means for driving said base member in said second direction. 3. A first group and a second group according to claim 1, wherein said second coil is disposed with its axial position shifted.
Stage equipment including groups. 4. The stage apparatus according to claim 1, wherein said stage is levitated by an air pad utilizing air pressure. 5. The stage device according to claim 4, wherein the first surface of the base member is a vertical surface, and the air pad is attracted by a magnetic force including a magnet and floated by air pressure.