JPH0412657A - Stage unit - Google Patents

Abstract

PURPOSE:To realize an ultra precise accuracy by differentiating the winding direction between first and second coils thereby producing forces along two directions in a plane. CONSTITUTION:A yoke 1 made of a material having high permeability, e.g. iron, is supported on a guide face 4 through a guide mechanism and a plurality of permanent magnets 2 are arranged, in stripe, on the yoke 1 while alternating the polarity. The yoke 1 is driven by a magnet section driving motor 3 in the direction perpendicular to the longitudinal direction of the permanent magnet and provided with a guide function for being moved in Y direction on a guide face 4. A main stage 7 is supported on the guide face 4 through an air pad 8 and a plurality of X coils 5 are disposed on the rear of the main stage 7 with same pitch as the permanent magnets 2 on the yoke 1. A plurality of Y coils 6 are also disposed on the rear of the main stage 7 perpendicularly to the X coils.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a stage device, and particularly to a stage device for moving an object within a two-dimensional plane.

[Prior Art] Conventionally, as a device for driving an object two-dimensionally, an An XY stage is known in which a Y stage is stacked with a servo motor for driving in the Y-axis direction and a ball screw.

Ball screws cannot completely eliminate play and backlash, and in order to transmit the driving force generated by the servo motor to the object, it is necessary to pass through a power transmission mechanism or guide mechanism in the middle, and the generated driving force cannot be transmitted to the object. It is not possible to convey this to the object 100%.

Viewed from another perspective, this results in distortion, elastic deformation, etc. occurring in some mechanical member or the like.

Depending on such a mechanism, it is difficult to achieve positioning accuracy of approximately 0.01 μm or less.

Problems to be Solved by the Invention] As explained above, it is difficult to realize an ultra-precise XY stage of 001 μm or less depending on the stage device using a servo motor and a ball screw.

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

Another object of the present invention is to provide a stage device with a simple structure, no play, and excellent positional accuracy.

[Means for solving the problem] A plurality of striped permanent magnets are arranged on a base member with their polarities alternately reversed. A plurality of first coils wound around an axis parallel to the striped permanent magnet are fixed to a stage. The direction intersecting the first coil is set as an axis, and a plurality of second coils wound around the axis are fixed to a stage. The lines of magnetic force emanating from the striped permanent magnets are arranged so that they have a higher density on the lower sides of the first and second coils than on the upper sides.

[Operation] Since the striped permanent magnets are arranged in parallel, lines of magnetic force emitted from the permanent magnets draw an arc in space and reach adjacent permanent magnets. When a part of the coil intersects with these magnetic lines of force, a force is generated in a direction perpendicular to the direction of current flow and the direction of the magnetic lines of force. By keeping the force exerted by the rest of the coil sufficiently small, a force can be applied to the coil in a predetermined direction. Since the first coil and the second coil are wound in different directions, forces can be generated in two directions within the 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.

A yoke 1 made of a material such as iron with high magnetic permeability is supported on a guide surface 4 using a guide mechanism such as a sliding guide or a rolling guide.4 On the yoke 1 is a permanent magnet 2 in the form of an elongated stripe. Or multiple pieces are arranged in parallel. In the figure, a permanent magnet 2 has magnetic poles on its upper and lower surfaces, and adjacent permanent magnets have alternately reversed magnetic poles. That is, if you look at the magnetic poles on the top surface of the permanent magnet, they are alternately arranged as N&, S poles, N poles, S poles, and so on. The yoke 1 is a motor 3 for driving the magnet part.
This allows the magnet to be driven in a direction perpendicular to the length direction of the permanent magnet. The yoke 1 has a guiding function for moving in the Y direction on the guiding surface 4.

This guidance can be realized by various methods such as sliding guidance and rolling guidance. A main stage 7 is supported on the guide surface 4 via an air pad 8. A plurality of X coils 5 are connected to the permanent magnets 2 on the yoke 1 on the lower surface of the main stage 7.
Further, on the lower surface of the main stage 7, a plurality of Y coils 6 are arranged in a direction perpendicular to the X coils. This Y coil 6 is also arranged with the same pitch as the permanent magnet 2.

The driving principle of the X coil and Y coil is shown in Figure 2 (A
) and (B). For simplicity, one turn of each coil will be taken out and illustrated.

FIG. 2(A) shows one turn of the X coil.

Permanent magnet 2 has an N pole on the top surface and an S pole on the bottom surface, and the lines of magnetic force emanating from the N pole head upward and eventually terminate at the adjacent permanent magnet of opposite polarity. Assume that it is placed directly above the magnet 2. Assume that a current flows through the coil 5 as shown by the arrow. Then, a force F as shown by the arrow acts on the lower side of the coil 5 due to the Lorentz force.

No force acts on the vertical side of the coil 5 while it is parallel to the lines of magnetic force; when the lines of magnetic force bend, opposite forces are generated on the left and right sides, or these forces are canceled out by using a plurality of X coils 5. A force acts on the upper side of the coil 5 in the opposite direction to the lower side, 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 Y coil is wound in a plane perpendicular to the X coil. The permanent magnet 2 generates magnetic lines of force similar to those described above. When a current as shown by the arrow is passed through the Y coil 6, a Lorentz force is generated in a direction perpendicular to the plane of the paper.In the case of zero illustration, a force F acts on the coil 6 from the back side to the front side of the plane of the paper.

FIG. 3 is a schematic cross-sectional view illustrating the driving of a two-dimensional stage having a combination of the X coil and the Y coil as shown in FIGS. 2(A) and 2(B).

In the figure, on a yoke 1, permanent magnets 2a, 2b, . Note that the magnetic poles exposed on the surface are arranged so as to alternately repeat N-3. Therefore, the lines of magnetic force emanating from the N pole terminate at the adjacent S pole.
-5b-5c.

5d is placed. In addition, the permanent magnet 2c in the center,
Y coils 6a and 6b are arranged above 2d.

A counterclockwise current as shown by the arrow in the figure is applied to the X coils 5a and 5C, and a clockwise current as shown by the arrow is applied to the X coils 5b and 5d. The lines of magnetic force on the permanent magnet 2a are directed upward, and the lines of magnetic force on the permanent magnet 2b are directed downward, so the forces acting when the current direction is reversed are in the same direction. Occur. Similarly, a force acts on the X coil 5C25d from the back side of the page toward the front side.

Note that when driving in the Y direction, the Y coils 6a, 6b
As indicated by the arrows shown in the figure, by flowing currents in opposite directions, forces are generated in the Y direction.

Note that it will be obvious to those skilled in the art that if the respective current directions are reversed, forces in opposite directions will be generated.

FIG. 4 is a plan view illustrating the movement mode of the stage. In FIG. 4(A), a current is applied to each Y coil in a direction that generates a force in the +Y direction. 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 that generates a force in the -X direction.

Therefore, a force in the -X direction is generated in each X coil. Therefore, the entire stage is translated in the -X direction.

In Fig. 4(C), the two X coils on the right are given current in a direction that generates a force in the +X direction, and the two X coils on the left are given a current in a direction that generates a force in the -X direction. It gives a current. Therefore, the entire stage is subjected to a downward force on the right side and an upward force on the left side, and performs rotational movement within the XY plane.

In this way, by exciting each coil in a desired direction, translation and rotation within the XY field plane can be performed arbitrarily.

FIG. 5 shows a partially enlarged view of the air pad shown in FIG. 1. The air pad 8 has a tact in the center for ejecting gas such as air, and a ring for applying magnetic attraction to the periphery. It has a shaped magnet 9. Note that the guide surface 4 is formed of a magnetic material such as iron.

When air at a constant pressure is ejected from the air pad, as the gap between the air pad 8 and the guide surface 4 narrows, the pushing force of the air becomes stronger and the pad is pushed up.4 As the gap widens, the resistance to the air flow increases. decreases, the magnetic attraction force prevails, and the pad is attracted. That is, the air pad attracts the stage 7 shown in FIG. 1 to the guide surface 4 and keeps the distance constant. When the Y coil 6 exerts force within the magnetic field and exerts a driving force parallel to the guide surface, the stage 7 moves along both directions according to the driving force. At this time, the air pad has almost no frictional force. Therefore, the stage 7 is prevented from being distorted due to frictional force.

65th! J indicates a vertical stage for SOR exposure.

A duct 21 through which the SOR light 15 travels is formed in the base 20, and the SOR light is supplied through a window 23.

Another base 25 is formed to face the base 20, and a yoke 24 having a guide surface is arranged on this base. A plurality of magnets 2 are arranged in stripes on the yoke 24 in a direction perpendicular to the plane of the paper. A stage 7 on which an X coil 5 and a Y coil 6 are arranged is held by an air pad 8 so as to face the permanent magnet 2 . The air pad 8 is attracted to the base 20 by magnetic force. Wafer chuck 1 is on the left side of stage 7.
A holder is attached to hold the semiconductor wafer 12. The stage 7 is supported by the air pad 8 while
It is driven by the Y coil 5 and the Y coil 6 to move to a desired position. Although not shown, the yoke 2
4 is provided with a mechanism that allows slight movement in the vertical direction in the figure with respect to the base 25.

In the embodiment described above, arbitrary driving can be performed in the X direction, but as for driving in the Y direction, the driving force becomes weaker as the Y coil 6 is shifted from above the permanent magnet 2. That is, driving in the Y direction is accompanied by ripple-like vibrations.

FIG. 7 shows another embodiment that can reduce the force ripple in the Y direction.

FIG. 7(A) shows a plan view, in which a plurality of m-long permanent magnets 2 are arranged in parallel. On top of that, two X coils 5a and 5b are placed on the left side, and two X coils 5c and 5d are placed on the right side! Three permanent magnets 2c, 2d, and 2e are exposed at the center. For the three permanent magnets in the center, Y
The Y coils 6a and 6b are arranged to face the permanent magnets 2d and 2e, and the other two Y coils 6c and 6d are arranged between the permanent magnets. That is, FIG. 7(B)
As shown in FIG.
When the coils a and 6b are arranged, the other Y coils 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 coil 6a
, 6b are gradually moved away from the top of the permanent magnet and moved to a position intermediate between the permanent magnets. At this time, the other Y coils 6c and 6d move from the intermediate region between the permanent magnets to above the permanent magnets. In this way, when the coils 6a, 6b lose their force (when they lose their force).

The other coils 6c and 6d begin to exert their power, and ripples are reduced.

A stage having a Y coil as shown in Fig. 7,
By incorporating it 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 in the vertical stage for SOR exposure as shown in FIG.

Note that although the present invention has been described along with limited examples, the present invention is not limited thereto.

For example, it will be obvious to those skilled in the art that various changes, improvements, combinations, etc. are possible.

For example, the number of permanent magnets and coils can be changed arbitrarily, and forms other than air pads can be used to hold the main stage.

The driving coil may be not only a coreless type but also a cored type, and the winding shape of the coil is not limited to that shown in the drawings.

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

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

Torques in X, Y, and θ2 can be applied directly to the stage, and the position and orientation can be controlled.

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

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

[Brief explanation of drawings]

Fig. 1 is a perspective view of a stage device according to an embodiment of the present invention, and Figs. 2 (A) and (B) are diagrams for explaining the driving principle of the X coil and Y coil of the stage device shown in Fig. 1. Conceptual diagram, Figure 3 is a conceptual diagram for explaining the drive of a two-dimensional stage equipped with an X coil and a Y coil, and Figure 4 (A>, (B)
), (C) are plan views for explaining the movement mode of the XY stage, Figure 5 is a schematic sectional view for explaining the function of the air pad, and Figure 6 is a diagram for explaining the vertical stage for SOR exposure. 7(A), (B), and (C) are a plan view and a partial sectional view for explaining other embodiments of the present invention. Yoke Permanent magnet drive motor guide surface Part 4<A) Coil for X (B) Coil for Y Drive principle Fig. 2 Coil for Y Coil Thrust force for X (A) Y translation (movement of BOX translation stage Fig. 4 (C) Rotation

Claims (5)

[Claims] (1) A base member that provides physical support and also serves as a yoke, and a plurality of striped permanent magnets arranged in parallel on the base member, each having magnetic poles along the normal direction of the base member. The adjacent striped permanent magnets include: a striped permanent magnet with reversed magnetic poles; a stage arranged to face the base member; and a stage fixed on a surface of the stage facing the base member;
a plurality of first coils wound around an axis parallel to the striped permanent magnet, the plurality of first coils being arranged such that the magnetic flux density on the upper side of the coil is sufficiently lower than the magnetic flux density on the lower side of the coil; , fixed on a surface facing the base member of the stage,
A plurality of second coils wound around an axis along a direction intersecting the axis of the first coil, the plurality of second coils being arranged such that the magnetic flux density at the upper side of the coil is sufficiently lower than the magnetic flux density at the lower side of the coil. A stage device having a second coil. (2) The stage device according to claim 1, further comprising means for driving the base member in the axial direction of the second coil. (3) In any one of claims 1 to 2, in the axial direction of the second coil, the second group has a first group arranged with the same pitch as the first coil, and a second group with a pitch shifted from the first group.
A stage device containing groups. (4) The stage device according to any one of claims 1 to 3, wherein the stage is levitated by an air pad using air pressure. (5) The stage device according to claim 4, wherein the base member has a vertical surface, and the air pad includes a magnet and is attracted by magnetic force and levitated by air pressure.