JPH03178746A - Two-dimensional moveable stage device - Google Patents

Abstract

PURPOSE:To position an object two-dimensionally at a high speed and with an extremely high accuracy by using a linear pulse motor in a coarse adjustment mechanism to obtain large driving forces, and in a fine adjustment mechanism an actuator capable of fine displacement. CONSTITUTION:The coarse adjustment mechanism 2 of a stage 19 operates in accordance with the principle of a linear pulse motor and transmits a predetermined amount of electricity to the respective exciting coils of a Y-direction mover structure 16 and X-direction mover structures 17, 18 to generate magnetic flux, and thereby the teeth 15 of an imitation stator 11 and the predetermined ones of a mover attract each other and the stage 19 is moved on the surface of the imitation stator 11 at the pitch of the teeth 15 by changes in the current flow through the exciting coils. Next, the imitation stator 11 is moved by a small distance within the pitch of the teeth 15 by the actuators 12 to 14 of a fine adjustment mechanism 1 and the stage 19 is moved in such a manner as following the stator 11 so that the stage 19 is stably positioned. The stage is thus positioned at a high speed and with a high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a stage device, and more particularly to a two-dimensional movable stage device that uses a linear pulse motor to move an object at a high volume within a two-dimensional plane.

2. Conventional technology] Conventionally, as a device for driving an object two-dimensionally, a device that drives an object in the Y-axis direction is placed on an An XYX stage is known in which a Y stage is stacked with a servo motor for driving and a ball screw.

Ball screws cannot completely eliminate backlash and backlash. Furthermore, in order to transmit the driving force generated by the servo motor to the object, a driving force transmission mechanism or a guide mechanism must be used on the way, and 100% of the generated driving force cannot be transmitted to the object. 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 high positioning accuracy of about 0.01 μm or less.

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

The purpose of the present invention is to provide a stage device suitable for realizing ultra-precise accuracy.6 Another purpose of the present invention is to provide a stage device suitable for realizing ultra-precise accuracy.
It is possible to provide a stage device with a simple structure, less play, and excellent positional accuracy.

Means for Solving 5 Problems] The basic configuration of the stage device of the present invention consists of two systems: a coarse movement system that provides a large driving force and a fast movement, and a fine movement system that provides a finer movement than the coarse movement system. The micro-movement system includes coagulation electrons having a plurality of teeth made of a high magnetic permeability material arranged at predetermined pitch intervals on a two-dimensional surface, and actuator means that can micro-move the coagulation electrons in a two-dimensional direction. On the other hand, the coarse motion system includes a plurality of teeth made of a high magnetic permeability material and formed with a pitch different from the pitch of the teeth of the solidified electrons, facing the teeth of the solidified electrons.
an excitation coil, and is movable in the two-dimensional direction with respect to the coagulated electrons by controlling energization of the wJ magnetic coil, with selected teeth of the plurality of teeth serving as magnetic poles; It consists of a stage fixed to the

The load of the stage itself is supported on the base by other support means such as air bearings.

[Effect] The coarse movement system operates on the principle of a linear pulse motor.

In other words, when the excitation coil of the mover is energized to a predetermined value,
A predetermined magnetic flux is generated from the mover, and the teeth of the coagulating electrons and the predetermined teeth of the mover attract each other due to the magnetic attraction force, and move toward the most stable position.Furthermore, by changing the current of the excitation coil, , the mover moves over the surface of the solidified electrons in a predetermined unit determined by the pitch of the teeth.

On the other hand, the actuator of the fine movement system is used to move the solidified electrons a minute distance within the pitch of the coarse movement system in a direction parallel to the surface of the actuator. As the solidified electrons move one stroke, the teeth of the mover follow the teeth of the stator and move slightly due to the magnetic attraction force, and come to rest at a stable position.

In this way, the coarse movement system can move the stage over a large distance at high speed to near the desired position, and the fine movement system can control the positioning to the desired position with high precision.

[Embodiment] FIG. 1 shows an external view of a two-dimensional movable stage device according to an embodiment of the present invention.
1, and fine movement actuators 12, 13, and 14 fixed on three sides around the coagulation electron 11, respectively. On the surface of the stator 11, a large number of protruding teeth 15 for a coarse movement system are formed in a matrix. The spacing between the teeth is precisely aligned at a predetermined pitch. In this embodiment, the teeth 15 are arranged with equal pinches in the X-Y directions of the illustrated arrows, which are perpendicular to each other. On the surface measuring section of IN extending in the Y direction of the condensing stator 1l, there are actuators 13 and 1.4, each of which can continuously expand and contract a predetermined minute amount in the Y direction.
One end of each is fixed via a joining member 1314°. The other ends of the Y-direction actuators 13, 14 are fixed to a common pace (not shown). An actuator 12 that can continuously displace a predetermined minute amount in the X direction is attached to one of the curved surfaces of the coagulation electron 11 extending in the X direction.
It is fixed via . X direction actuator 12
es is also determined by a common base (not shown). The Y-direction actuators 13 and 14 have hinge parts that can be elastically deformed in the X direction, and the X-direction actuator 12 has a hinge part that can be elastically deformed in the Y direction.

Therefore, each allows the other to deform. By simultaneously expanding and contracting the actuators 13 and 14 by the same distance, the coagulation electrons 11 are driven in the Y direction, and at the same time the X-direction actuator 12 is elastically deformed in the Y direction, so that the coagulation electrons 11 move in the Y direction.

On the other hand, as the X-direction actuator 12 expands and contracts, the coagulation electrons 11 receive a force in the X-direction. If the Y-direction actuator 13.14 is not operating, the force is applied only to one surface of the coagulation electron 11, so a rotational moment is generated around the Z-axis perpendicular to the X and Y axes, and the actuator 13.14 Elastically deforms in the X-axis direction. The solidification electron 11 is connected to the base of the X-direction actuator 12 at the connection point 1
It rotates slightly around the Z-axis using the fulcrum as the fulcrum. By driving the two Y-direction actuators so as to cancel out this minute rotation, translation in the X-direction can be achieved.

Moreover, two or more of the three actuators can be driven simultaneously to rotate the coagulation electrons 11 within the XY plane. Therefore, the coagulation electrons 11 in this embodiment are in the X direction and in the Y direction.
The minute movement in the direction and the rotational movement around the Z axis within the XY plane can be performed simultaneously or selectively.

FIG. 2 shows an example of the structure of each actuator, taking the X-direction actuator 12 as an example. The actuator 12 includes a cylindrical laminated piezoelectric element 20.

Piezoelectric plates made of ceramic or the like are laminated with electrodes for applying heavy pressure on both sides, and the electrodes are collectively led out by lead wires. When zero voltage is applied to this lead wire in all directions, it expands and contracts in the X direction, causing mechanical displacement.

In order to stabilize the amount of displacement, the pressure element having a laminated structure is housed in a metal case, and a predetermined preload is applied thereto.

The amount of displacement can be controlled by adjusting the applied voltage.

This piezoelectric actuator 12 includes spherical hinges 21 and 22 at both ends of the piezoelectric element 20.

The spherical hinges 2I, 22 have a semicircular or arcuate cross-sectional shape, with the diameter narrowed from both sides toward the smallest diameter portion, and have high rigidity in the X-axis direction or are perpendicular thereto. Rigidity is lowered in the Y and Z axis directions,
It is elastically deformable.

Generally, the amount of displacement due to the piezoelectric effect of a piezoelectric body can be controlled in a very small amount, and the displacement can also be controlled in units of several thousandths of micrometers. It is also possible to increase the amount of displacement as a whole by using a laminated type. Therefore, by combining an appropriate number of piezoelectric layers and adjusting the pressure, it is possible to
It is possible to stably control minute movements on the order of 1/0 μm. Further, since the pressure body can have sufficiently high rigidity in the direction of displacement, it can exert sufficient driving force.

The pond Y-direction actuators 13 and 14 have a similar configuration. Note that since the embodiment shown in FIG. 2 uses a spherical hinge, the actuators 12, 13, and 14 are
It can be elastically deformed in the direction.

For example, three or more Z-direction actuators can be provided on the back surface of the coagulation electron 11 to configure a six-axis movable table in the x, yz directions and the rotation direction in space. X direction,
When configuring a stage with three degrees of freedom in the Y direction and rotation in the X-Y plane, a hinge capable of elastic deformation in only one axial direction of the pond other than the displacement direction may be used.

Next, the coarse movement system 2 will be explained. The coarse movement system 2 is set to have a larger amount of movement and a faster movement speed than the fine movement system 1. Its structure consists of solidified electron teeth 1
5, a Y-direction mover structure 16 and an X-direction mover structure 17 in a slider configured to slide on a pseudo-stator.
18 and one stage carried on a slider. Mover structure 1
6.17.18 and the coagulating electrons 11 are opposed to each other with a predetermined gap, for example, approximately several tens of micrometers/111'o. The mover structure and the stage are guided and supported by a support device (not shown) such as an air bearing device so as to be movable in the X-Y directions, for example, on a common base (not shown) provided on the right side of the drawing.

The operating principle of the linear pulse motor of the coarse movement system 2 will be explained with reference to FIGS. 3(A) and 3(B).

FIG. 3(A) shows a partial cross-sectional structure along the Y axis of the solidified electrons 11 and the Y-direction mover structure 16 in FIG. pole and S
It has a U-shaped magnetic core (core) 32, 33 fixedly connected to the pole, and first-phase and second-phase excitation coils 34, 35 wound around the core 3233, respectively. Each li! The pitch between the i-poles is different from the pitch of the teeth 15 of the solidified electrons 11 as shown.

Now, as shown in FIG. 3 (A>), if current is passed in the same direction through the left coil 34 and right coil 34 as shown by the arrows, both ends of the permanent magnet 31 will be in the same direction as the permanent magnet 31. t magnets are formed.These magnets are combined and have magnetic poles a and d.
Between the magnetic flux caused by the permanent magnet 31 and the w of the coil 34.35
Magnetic flux due to J magnetism or combined magnetic flux is generated, and magnetic pole a,
A force is generated that attracts each other to form a magnetic path between the teeth 15a and 15f of the coagulated electrons 11 closest to d.

Since the pitch of the magnetic poles of the mover structure 16 and the pitch of the teeth of the coagulating electrons 11 are not aligned, an attractive force is generated to form a stable magnetic path. , a component in the Y direction also occurs.

Therefore, the mover structure 16 is driven in the Y direction.

In this case, in the magnetic poles b-c, the directions of the magnetic flux due to the permanent magnet 31 and the magnetic flux due to the excitation of the coil are made to be equally opposite, so the magnetic flux cancels each other out and becomes zero, and the magnetic flux is generated between the coagulated electron teeth 15. No suction force is generated.

Next, as shown in FIG. 3(B), when the direction of the excitation current in the left coil 34 is reversed while the current direction in the right-hand coil 35 is fixed, the permanent magnet 31 and the excitation current, a composite magnetic flux is generated, and a magnetic path as shown in the figure is formed between the teeth 15c and 15f of the coagulating electrons 11.

At this time, at @iia, c, the magnetic flux due to the excitation current and the magnetic flux due to the permanent magnet 3I are opposite in direction and have the same magnitude, so they cancel each other out.

Referring to the mover separation lid, in the state of FIG. 3(A), it was on the left side of the tooth 15f due to the influence of the coagulating electron tooth 15a, and in the state of FIG. 3(B), it was on the left side of the coagulating electron tooth 15c. Due to this influence, it is driven to the right side of the tooth 15f. Therefore, between FIG. 3(A) and FIG. 3(B), the moving element structure 16 is given a driving force and moves in the Y direction (rightward in FIG. 3C).

Next, while keeping the current direction of the left coil 34 fixed,
When the current direction of the excitation coil 35 on the right side is reversed, the magnetic pole becomes
A composite magnetic flux is generated between teeth 15c and 15e of stator 11.
The magnetic path changes between the two, and the mover structure 16 further moves in the Y direction. Additionally, if the current direction of the left side excitation coil 34 is reversed while the current direction of the right side coil 35 is fixed, a composite magnetic flux is generated between the magnetic poles a and C, and the stator 1
A magnetic path moves between the first teeth 15b and 15e, and the mover 16 moves in the Y direction.

The above switching of the excitation current is shown in the waveform diagram of Fig. 4. As shown in Fig. 4, when the current direction of the two-phase excitation coils 34 and 35 is alternately switched and a combined pulse of the excitation current is applied, 1 It becomes a cycle operation. I [If the pitch of the teeth 15 of the I electron 11 is P, I
The mover structure 16 moves linearly by P in the Y direction.

If the combination of excitation directions is completely opposite to the above, the movement direction will be linear movement in the opposite direction. Therefore, per excitation pulse (
The movement of the stage can be controlled with an accuracy of 1/4)P. Naturally, if the gap length P is made small, the moving distance per pulse can be made small. Also, tII of the mover structure
Even if the number of driving currents is increased and the number of phases of the drive current is increased, the moving distance can be reduced. Further, by adjusting the size of the excitation main flow, a large magnetic attraction force can be obtained, so that a large propulsive driving force can be obtained.

Note that the moving element structure 18.1 in the X direction also has a similar structure and operation.

Next, how the stage 19 is moved by the arrangement of the X and Y mover structures shown in FIG. 1 will be explained with reference to FIGS. 5(A) to 5(C).

Figure 5 (,~) shows a Y-direction mover structure (*16 is arranged at the center of gravity of the stage 19 so that its magnetic poles are arranged in the Y-direction), showing the case where one stage is driven in the Y-direction. ,
When the current to the exciting coil is controlled in the manner described above, the stage 19 is translated in the Y direction as indicated by the arrow in the figure.

As shown in FIG. 5(B), the X-direction mover structure 17.18
If the same current value and drive amount flow of excitation control in the same direction are applied to both X-direction mover structures 17 and 18 synchronously,
Since the driving forces are equal in the same direction, the stage 19 is translated in the X direction as shown by the arrow in the figure. On this occasion,
In the figure, the combined force of the driving forces of both movable structures 17 and 18 is set to pass through the center of gravity of the stage 19. When the resultant force deviates from the center of gravity, a rotational moment is generated.

FIG. 5(C) shows a case where the driving directions of both X-direction moving child structures 17 and 18 are controlled to be opposite to each other. this is,
This is done by controlling the direction of current flowing through the excitation coils of each X-direction mover structure 1718 in a completely opposite relationship. As a result, the stage 19 rotates around the Z axis.

By controlling the fine movement system 1 and coarse movement system 2 explained above, the stage 1
A method for precisely controlling the movement of one to a desired position will be explained.

First, the coarse movement system 2 moves the stage 19 near the target position at high speed. This is done by feeding back a signal from a position detection device (not shown) to the excitation@current control of the coarse movement system 2. Then, just before or after the rough movement reaches the vicinity of the target position, control of the coarse movement system 2 is stopped, and driving of the membrane stator 11 by the fine movement system 1 is started.

A position detection device (not shown) detects the difference between the target position and the current position of one stage, and a calculation device (not shown) determines the amount of displacement of the actuators 12, 13, 14 corresponding to the difference. An applied voltage corresponding to the amount of displacement of the actuator is determined and applied to a predetermined actuator. #11 of the 4wi stator 11 where the teeth 15 of the coagulation electron 11 move slightly when the actuator moves slightly.
When the membrane stator 5 moves slightly, the magnetic poles of the mover structures 16, 17, and 18 that connect it receive a driving force due to the magnetic attraction force so as to form a stable magnetic path, and as the membrane stator 11 moves, the magnetic poles of the mover structures 16, 17, and Move slightly. Therefore, by coarse movement system 2 (1'4)
The stage 19 can be precisely positioned at the target position by performing two-dimensional movement control with P precision and, in addition, by performing two-dimensional movement control on the order of 1/100 μm using the fine movement system 1.

Note that the slider structure is not limited to the arrangement shown in Figure 1, but can be arranged in various numbers and combinations, taking into account the size of the stage, the negative intensities of the moving object, the moving range, the moving direction, etc. It is possible to choose the placement. In addition, the fine movement actuator is not limited to the arrangement as in No. 11121, but may be provided with two in each of the X and Y directions, or if the membrane stator has an irregular shape other than a rectangular shape. If so, an appropriate arrangement may be selected depending on the desired mode of movement.

Next, FIG. 6 shows a cross-sectional structure of an example in which a two-dimensional movable stage device is applied to an aligner of semiconductor manufacturing equipment. In FIG. 6, the same reference numbers as in FIG. 1 indicate similar components. 61 is a base with sufficiently high rigidity, and the fine movement system 1
and coarse movement system 2 are movably supported at predetermined positions. The membrane stator structure 11 of the fine movement system 1 is mounted on the base 61 by an X-direction actuator 12, a Y-direction actuator 13, 14 (not shown). On the other hand, the coarse movement system 2 has an X
, Y-direction mover structures 17, 18, and 16 are provided, respectively. A wafer 62 is placed on the opposite surface. An opening 63 is provided in the base 61, and light from a light source is irradiated onto the wafer 62 from the direction of the arrow through a mask (not shown) or the like. Stage 19 is suction tx,
The 6-adsorption air bearing device 64, which is supported by the a-bearing device 64 on the base 61 of the optical a-meter with almost no friction, attracts the stage I9 to the base 61 by, for example, magnetic force, and allows the stage I9 to be attracted to the base 61 by, for example, air pressure. Generates a force that creates a constant distance between the two. The attractive force of the air bearing device and the magnetic attractive force of the coarse movement system 2 are balanced and adjusted so that the distance between the moving element structure and the pseudo stator 11 is maintained approximately at a predetermined distance. Therefore, the stage 19 is controlled by the coarse movement system 2 and the fine movement system 1 to move smoothly on the base 6I with almost no friction.
This device may be used with the Y direction being the gravitational direction, or the Z direction being the gravitational direction.

Note that when using the Y direction as the gravity direction, the stage device 19 has almost no frictional force against the base 61, so when aligning one stage with the opening s63, always A bias driving force corresponding to the weight of the moving part of the coarse movement system l is applied to the Y-direction mover 1 in the opposite direction to the gravity of the Y-direction.
It is better to give it by 6.

The two-dimensional movable stage device described above is not limited to aligners for semiconductor devices, but also ultra-S dense mechanical devices, processing devices,
It can be applied to various devices that require precise two-dimensional movement control of objects such as robots and X-Y 7' locks.

Although the present invention has been described above with reference to the embodiments, it will be obvious to those skilled in the art that the present invention is not limited to these examples, and that, for example, various modifications, improvements, combinations, etc. can be made.

[Effects of the Invention] As explained above, according to the present invention, a linear pulse motor is used in the coarse movement system to obtain a large driving force that is accurate and eliminates backlash and backlash, and furthermore, a fine movement system can be used to generate small displacements. Obtain minute movements of the pulse motor itself using an actuator that can.

By combining these coarse movement systems and fine movement systems, it is possible to provide a high-speed, ultra-precise two-dimensional or more moving stage device for objects.6 Both the coarse movement system and the fine movement system have simple structures and operating principles. Therefore, the entire device can be compact and configured into a single piece.

[Brief explanation of drawings]

FIG. 1 shows a two-dimensional motor type X-Y according to an embodiment of the present invention.
FIG. 2 is a side view of a piezoelectric actuator used in the device of FIG. 1, and FIGS. 3(A) and (B) are a linear pulse motor according to an embodiment of the present invention. Figure 4 is a drive waveform diagram of the linear pulse motor in Figure 3. Figures 5 (A), (B), and (C) are stages in the embodiment of the present invention. FIG. 6 is a diagram illustrating an example in which a stage device according to an embodiment of the present invention is applied to an aligner of a semiconductor manufacturing device. In the figure, l Fine movement system 2 Coarse movement system 1.1 Pseudo stator 12 X-direction actuator 13.14
Y-direction actuator 15 Stator teeth 16 Y-direction mover W4 structure 17.18
X-direction mover structure 19 Stage 21.22 Spherical hinge 31 Permanent magnet 32.33 Core 34.35 Excitation coil 61 Base 62 Wafer 63 Opening 64 Air bearing device

Claims (3)

[Claims] (1) a pseudo stator having a two-dimensional surface and having a plurality of teeth made of a high magnetic permeability material arranged at a predetermined pitch on the surface; and arranged at a predetermined distance from the pseudo stator; a plurality of teeth made of a high magnetic permeability material arranged to face the teeth of the pseudo stator at a pitch different from the pitch of the teeth of the pseudo stator;
an excitation coil, and is movable in the two-dimensional direction with respect to the pseudo stator by controlling energization of the excitation coil to use selected teeth among the plurality of teeth as magnetic poles; A two-dimensional movable stage device comprising: a stage fixed to a movable element; and actuator means that connects the pseudo-stator to a base and can minutely move the pseudo-stator in the two-dimensional direction with respect to the base. (2), the actuator means includes first and second actuators having piezoelectric elements having displacement directions in the X direction and the Y direction, which are orthogonal to each other on the surface of the pseudo stator; The two-dimensional movable stage device according to claim 1, having a structure capable of elastic displacement in a direction perpendicular to the above direction. (3) Each of the actuators includes a piezoelectric element that can be piezoelectrically displaced in the longitudinal direction, and is provided at both ends of the piezoelectric element in the longitudinal direction, has high rigidity in the longitudinal direction, and can be elastically displaced in a direction perpendicular to the longitudinal direction. The two-dimensional movable stage device according to claim 2, further comprising a hinge.