JP2007188251A - Stage apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To cancel reaction force and reaction force moment caused when a stage is driven. <P>SOLUTION: A stage apparatus 10 comprises an X stage 30, a stone surface plate 40, canceling actuators 60A, 60B for canceling vibration caused by reaction force, and a mount 70. A control part 80 is connected to a reaction force processing operation part 90 and has a signal route 86 branched so as to supply a stage drive command (b) from a controller 82 to the reaction force processing operation part 90. The reaction force processing operation part 90 comprises a cancel thrust operation part 92 to which the stage drive command (b) is input and drivers 94a to 94d for generating a drive signal (f) corresponding to a reaction force drive command (e) from the cancel thrust operation part 92. The cancel thrust operation part 92 calculates a drive command (e) to the canceling actuators 60A, 60B so as to generate thrust corresponding to the level of reaction force caused when an X linear motor 26 drives the X stage 30. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a stage apparatus, and more particularly to a stage apparatus configured to prevent a base that supports a stage from tilting due to a moment generated by a reaction force when the stage is moved.

  The stage device is required to move the stage horizontally with high precision, and the linear motor thrust is controlled so that the sliders provided at both ends of the stage are moved at a predetermined speed by the thrust of the linear motor. ing. Furthermore, the linear motor is supported by a stone surface plate (base) having a large weight so that the stage can be driven with low friction by a static pressure pad constituting an air bearing on the stone surface plate. It is configured.

  On the other hand, the gantry that supports the stone surface plate is provided with a vibration isolation unit that absorbs vibrations propagating from the floor, so that external vibrations are not transmitted to the stone surface plate. In the stage apparatus configured as described above, when the stage is moved by the thrust of the linear motor, the reaction force is received by the stone surface plate. The stone surface plate has high rigidity and large enough mass so that it will not be deformed by the reaction force from the linear motor, but the vibration isolation unit that supports the stone surface plate can be elastically deformed with a spring member and a damper function. Due to the configuration, the reaction force propagated through the stone surface plate causes minute elastic deformation in the direction opposite to the moving direction of the stage. As a result, a minute displacement is applied to the stone surface plate supported by the gantry.

In order to suppress the effect of reaction force when moving the stage, an actuator that generates a force in the opposite direction to the reaction force when the linear motor moves the stage is provided to cancel the reaction force. There is a stage device (see, for example, Patent Document 1).
JP 2004-302039 A

  However, in Patent Document 1, an actuator that cancels the reaction force of the linear motor is disposed on the side of the stone surface plate, and therefore, the operation of the transport mechanism that transports the work to the work table on the stage is limited. There was a problem.

  In addition, if the actuator is placed at a different height from the horizontal plane on which the stage moves to solve the above problem, a moment around the center of gravity of the stage is generated by the reaction force. A slight tilt will occur.

  In view of the above circumstances, an object of the present invention is to provide a stage apparatus that solves the problem.

  In order to solve the above problems, the present invention has the following means.

  The invention according to claim 1 is a stage, an actuator that moves the stage, a base that supports the actuator, a base that supports the base, and a vibration isolation that absorbs vibration between the base and the base. In a stage apparatus having a unit and a control unit that controls the actuator, a canceling unit that cancels a horizontal reaction force generated when the actuator drives the stage and a reaction force moment acting around the center of gravity of the stage An actuator is provided.

  According to a second aspect of the present invention, the canceling actuator is attached to be inclined at a predetermined angle with respect to a horizontal direction in which the stage is moved, and cancels the reaction force and the reaction force moment by distribution according to the inclination angle. It is characterized by that.

  According to a third aspect of the present invention, the canceling actuator includes a linear motor that moves the mover in the moving direction of the stage relative to the stator, the stator is supported by the gantry, and the mover is It is connected to the lower surface of the base.

  According to a fourth aspect of the present invention, the control unit includes reaction force processing control means for generating a drive command for the canceling actuator in synchronization with a stage drive command for the actuator.

  According to a fifth aspect of the present invention, the control unit generates a stage thrust calculation means for generating a stage drive command to the actuator, and a signal path for supplying the stage drive command from the stage thrust calculation means to the reaction force processing control means. The reaction force processing control means generates a canceling thrust corresponding to the stage driving command to the canceling actuator together with the supply of the stage driving command.

  According to the present invention, since the actuator for canceling the horizontal reaction force generated when the actuator drives the stage and the reaction force moment acting around the center of gravity of the stage is provided, the operation of the transport mechanism for transporting the workpiece can be performed. It is not limited, and the moment around the center of gravity of the stage can be suppressed to prevent the base from tilting.

  Further, according to the present invention, the canceling actuator is attached to be inclined at a predetermined angle with respect to the horizontal direction in which the stage is moved, and in order to cancel the horizontal reaction force and reaction force moment by distribution according to the inclination angle. The horizontal reaction force and reaction force moment can be canceled simultaneously by one actuator, the number of canceling actuators can be reduced, the configuration can be simplified, and the canceling actuator can also be easily controlled.

  Further, according to the present invention, since the drive command to the cancel actuator is generated in synchronization with the stage drive command to the actuator, the reaction force canceling control can be performed at the same timing as the reaction force generation. Disturbances due to timing differences of the actuators can be prevented.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a plan view showing an embodiment of a stage apparatus according to the present invention. FIG. 2 is a front view of the stage apparatus. FIG. 3 is a side view of the stage apparatus. As shown in FIGS. 1 to 3, the stage apparatus 10 includes a Y stage 20, an X stage 30, a stone surface plate 40, a vibration isolation unit 50, and a cancellation actuator 60 </ b> A that cancels vibration caused by a reaction force. 60B and a pedestal 70.

  The Y stage 20 has a horizontal portion 22 extending in the X direction, and a slider 24 coupled to both ends of the horizontal portion 22. Further, the horizontal portion 22 is provided with an X linear motor 26 for moving the X stage 30 in the X direction and an X linear scale 28. The X linear motor 26 includes a stator (yoke) 26 a fixed to the horizontal portion 22 and extending in the X direction, and a mover (coil) 26 b coupled to the lower surface of the X stage 30. .

  In addition, an air pad 32 that slides on the top surface of the stone surface plate 40 is attached to the bottom of the X stage 30 and moves along the horizontal portion 22 with low friction in the X direction.

  Further, the stone surface plate 40 has a Y guide 42 for guiding the slider 24 in the Y direction on the upper surface, a Y linear motor 44 for driving the slider 24 in the Y direction, and a linear scale 46 for measuring the position of the slider 24. . The Y linear motor 44 includes a stator (yoke) 44 a fixed to the stone surface plate 40 and extending in the Y direction, and a mover (coil) 44 b coupled to the side surface of the slider 24. An air pad 48 that forms an air layer is attached to the slider 24 so as to face both side surfaces of the Y guide 42, and moves along the Y guide 42 with low friction in the Y direction.

  In a space formed between the stone surface plate 40 and the gantry 70, a vibration isolation unit 50 and canceling actuators 60A and 60B are arranged. Accordingly, since the canceling actuators 60A and 60B are provided below the stone surface plate 40, the operation of the transport mechanism (not shown) for transporting the workpiece is not limited, and the base is controlled by suppressing the moment around the center of gravity of the stage. Inclination can be prevented.

  The vibration isolation unit 50 is formed of an elastic body such as an air spring or rubber, and absorbs vibration so that vibration from the floor surface input via the gantry 70 does not propagate to the stone surface plate 40. . The vibration isolation unit 50 is disposed near the corners of the four corners of the stone surface plate 40 and is configured to absorb vibration components in the vertical direction. Here, the reaction force when the X stage 30 is moved by the thrust of the X linear motor 26 is propagated to the stone surface plate 40 via the horizontal portion 22, the slider 24, and the Y guide 42. At that time, a reaction force in the horizontal direction and a moment about the center of gravity of the X stage 30 act on the stone surface plate 40. When this reaction force moment is applied to the stone surface plate 40, the vibration isolation unit 50 on one side receives a compressive load and the vibration isolation unit 50 on the other side receives a tensile load depending on the direction of the moment. Since the vibration isolation unit 50 is elastically deformed in the vertical direction so as to absorb vibration, the side surface of the stone surface plate 40 vibrates in the vertical direction, and the vibration is attenuated by the damper function of the vibration isolation unit 50.

  The canceling actuators 60A and 60B are composed of a linear motor in which a stator 60a and a mover 60b are combined, and the stator 60a and the mover 60b have an inclined table 62a having an inclined surface inclined by a predetermined angle θ with respect to the horizontal direction. , 62b are attached to the upper surface of the gantry 70 and the lower surface of the stone surface plate 40. The canceling actuators 60A and 60B are attached in such a direction that the mover 60b moves in the X direction with respect to the stator 60a so as to cancel the reaction force in the X direction. Furthermore, the inclination angle θ is set so that the inclination directions of the canceling actuator 60A arranged on the left side and the reaction force processing actuator 60B arranged on the right side are different from each other by 180 °.

  Four canceling actuators 60A and 60B are arranged on the lower side of the stone surface plate 40, and the total value of their horizontal component forces is balanced with the reaction force in the X direction when the X stage 30 is moved. Thrust is generated in the direction of the inclination angle θ so that the total value of the moments due to the directional component balances the reaction force due to the moment centered on the center of gravity of the X stage 30 when the X stage 30 is moved.

  FIG. 4 is a block diagram showing the configuration of the control unit of the stage apparatus. As shown in FIG. 4, the control unit 80 is applied to the mover (coil) 26 b of the X linear motor 26 based on the controller 82 that controls the X linear motor 26 and the stage drive command b from the controller 82. And a driver 84 for generating a drive signal c. When the stage drive command a is input, the controller 82 outputs the stage drive command b to drive the X stage 30, and the position detection signal d of the X stage 30 from the X linear scale 28 and the stage drive command a are A stage drive command b corresponding to the difference is output.

  The control unit 80 is connected to the reaction force processing calculation unit 90 and has a signal path 86 branched so as to supply the reaction force processing calculation unit 90 with the stage drive command b from the controller 82. The reaction force processing calculation unit 90 includes a cancel thrust calculation unit 92 to which the stage drive command b is input, and drivers 94a to 94d that generate a drive signal f corresponding to the reaction force drive command e from the cancel thrust calculation unit 92. Have.

  The cancel thrust calculation unit 92 uses the calculation formula described later to the cancel actuators 60A and 60B so as to generate a thrust corresponding to the magnitude of the reaction force generated when the X linear motor 26 drives the X stage 30. The drive command e is calculated. Therefore, the cancel thrust calculation unit 92 generates the drive command e to the cancel actuators 60A and 60B in synchronization with the stage drive command b to the X linear motor 26. Since it can be performed at the same timing, it is possible to prevent a disturbance due to a timing difference between the canceling actuators 60A and 60B.

  Here, the reaction force processing calculation formula will be described with reference to FIG. 5 schematically showing the stage apparatus 10. In FIG. 5, when the X stage 30 is driven by the driving force (thrust) Fs of the X linear motor 26, the X stage 30 generates a moment Ms around the center of gravity G1. When the reaction force -Fs at this time propagates to the stone surface plate 40, the stone surface plate 40 generates a moment Mb around the center of gravity G2. These moments Ms, Mb and reaction force −Fs affect the settling performance of the X stage 30. In this embodiment, the moments Ms and Mb and the reaction force −Fs can be canceled simultaneously by applying the thrusts of the canceling actuators 60A and 60B to the stone surface plate 40. The principle will be described below.

  When the stage drive thrust is Fs and the thrust generated by the canceling actuators 60A and 60B is Fr, reaction force -Fs and moment Mb against the thrust Fs as shown in FIG.

As shown in FIG. 5, the thrust Fr of the canceling actuators 60A and 60B can be decomposed into a component force Frx in the horizontal direction (X direction) and a component force Frz in the vertical direction. become that way.
Frx = Fr · cos θ (1)
Frz = Fr · sinθ (2)
When the following equation (3) holds, the thrust in the horizontal direction (X direction) is canceled by the four canceling actuators 60A and 60B.
-Fs + 4 ・ Frx = 0 (3)
Therefore, the component force Frx in the horizontal direction (X direction) is obtained as follows.
Frx = Fs / 4 (4)
Next, when the X stage 30 is driven, the reaction force moments Ms and Mb applied to the center of gravity G1 of the X stage 30 and the center of gravity G2 of the stone surface plate 40 are obtained as follows. In the following, the counterclockwise direction is negative. The distance from the thrust acting point of the X linear motor 26 to the center of gravity G1 is represented as H1, and the distance from the thrust acting point of the X linear motor 26 to the center of gravity G2 is represented as H2.
Ms = −Fs · H1 (5)
Mb = −Fs · H2 + 2Mr (6)
Here, if the distance from the center of gravity G2 of the stone surface plate 40 to the canceling actuators 60A and 60B is L, the reaction force processing moment Mr can be expressed by the following equation (7).
Mr ＝ Frz ・ L ・ ・ ・ (7)
At this time, the reaction moments Ms and Mb are canceled when the following equation (8) is satisfied.
Ms + Mb = 0 (8)
The above formulas can be summarized as the following formula (9).
Frz = (H1 + H2) ・ Fs / 2L (9)
From the above equations (1), (2), (4), and (9), the mounting angle θ of the canceling actuators 60A and 60B and the thrust Fr of the canceling actuators 60A and 60B are obtained by the following equations.
θ = tan ⁻¹ ((H1 + H2) / L) (10)
Fr = Fs / (2 · cos θ) (11)
Thus, since the thrust Fr of the canceling actuators 60A and 60B is obtained from the tilt angle θ of the canceling actuators 60A and 60B and the thrust Fs of the X linear motor 26, the tilt angle θ is set to an arbitrary fixed value. The reaction force moments Ms, Mb corresponding to the thrust Fr of the canceling actuators 60A, 60B and the reaction force -Fs of the thrust of the X linear motor 26 can be canceled simultaneously. Accordingly, the horizontal reaction force −Fs and the reaction force moments Ms and Mb can be canceled simultaneously by a single actuator, the number of canceling actuators can be reduced, the configuration can be simplified, and the canceling actuators 60A and 60B can be simplified. This can be easily controlled.

  FIG. 6 is a plan view schematically showing a modification. As shown in FIG. 6, canceling actuators 60A and 60B for canceling the reaction force in the X direction are provided below the stone surface plate 40, and the canceling actuators 62A and 62B for canceling the reaction force in the Y direction are fixed. Provided below the panel 40.

  This modification can also be applied to the surface type stage device 110 in which the stage 100 moves two-dimensionally on the flat surface of the stone surface plate 40. Reaction force in the X direction -Fs, reaction force moments Ms, Mb, and the reaction force and reaction force in the Y direction when the stage 100 is driven can be canceled, and the stage 100 is simultaneously moved in the X and Y directions. Reaction force processing when moving is possible.

  In the above-described embodiment, the configuration in which the stone surface plate 40 is supported by the vibration isolation unit 50 has been described as an example. Of course, it can be applied.

It is a top view which shows one Example of the stage apparatus by this invention. It is a front view of a stage apparatus. It is a side view of a stage apparatus. It is a block diagram which shows the structure of the control part of a stage apparatus. It is a figure for demonstrating a computing equation. It is a top view which shows a modification typically.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Stage apparatus 20 Y stage 24 Slider 26 X linear motor 28 X linear scale 30 X stage 40 Stone surface plate 42 Y guide 44 Y linear motor 46 Linear scale 50 Anti-vibration unit 60A, 60B Canceling actuator 70 Base 80 Control part 82 Controller 84 Driver 90 Reaction force processing calculation unit 92 Cancel thrust calculation units 94a to 94d Driver 110 Surface type stage device

Claims (5)

A stage, an actuator that moves the stage, a base that supports the actuator, a gantry that supports the base, a vibration isolation unit that absorbs vibration between the base and the gantry, and the actuator In a stage apparatus having a control unit,
A stage apparatus comprising: a canceling actuator for canceling a horizontal reaction force generated when the actuator drives the stage and a reaction force moment acting around the center of gravity of the stage.   2. The canceling actuator is attached at a predetermined angle with respect to a horizontal direction in which the stage is moved, and cancels the reaction force and the reaction force moment with a distribution according to the inclination angle. The stage apparatus described in 1.   The canceling actuator is composed of a linear motor that moves the mover in the moving direction of the stage relative to the stator, the stator is supported by the mount, and the mover is coupled to the lower surface of the base. The stage apparatus according to claim 1, wherein: The controller is
5. The stage apparatus according to claim 1, further comprising a reaction force processing control unit that generates a drive command to the canceling actuator in synchronization with a stage drive command to the actuator. The controller is
Stage thrust calculation means for generating a stage drive command to the actuator;
A signal path for supplying a stage drive command from the stage thrust calculation means to the reaction force processing control means,
2. The stage apparatus according to claim 1, wherein the reaction force processing control unit causes the canceling actuator to generate a canceling thrust corresponding to the stage driving command together with the supply of the stage driving command.

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