JPH03257914A - Stage equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application]
It is related to a stage that is moved in Yθ, and is used, for example, in semiconductor manufacturing equipment, high-precision processing machines, f! XY of density measuring instruments, etc.
The present invention relates to a precision stage applied to a stage or an XYθ stage.

[Prior Art] Conventionally, stage devices that move in the XYθ directions have mainly had a three-stage structure in which a drive section and a guide section are provided in each direction.

Figure 10 shows a conventional stage device, where 1 is θ
The wafer is placed on a stage 51 and moves in XYθ in the figure, 54 is a stage base, and 53 is a Y that is placed on a stage base 54 and is movable in the Y direction with respect to the stage base 54.
A stage 52 is placed on the Y stage 53 and is movable in the X direction with respect to the Y stage 53. An X stage 51 is placed on the X stage 52 and is θ relative to the X stage 52.
θ stage movable in the direction, 56 is a stage base 54
A motor Y is fixed to the Y stage 53 to drive the Y stage 53.
55 is a motor X that is fixed to the Y stage 53 and drives the X stage 52; 57 is an interferometer that measures the position of the X stage 52 in the X direction; and 158 is the Y of the X stage 52.
Interferometer Y, 59, which measures the position in the direction, is the X stage 52
This is a mirror placed on top of the X stage 52 to measure the position of the X stage 52 using an interferometer. Further, the stage base 54 is provided with a guide in the Y direction, and the Y stage 53 is provided with a guide in the X direction.

Here, the wafer 1 is moved along each of the XYθ guides by a motor serving as a drive unit, and its positioning is controlled by the measurement value of the interferometer. (In this example, positioning is controlled in the XY force directions.) For example, to move and position the wafer 1 in the X direction, a motor X55 is driven by a transmission system (not shown). For example, the Y stage 53 is moved along the guide of the stage base 54 using a ball screw, and stopped when the measured value of the interferometer reaches a predetermined value.

[Problems to be Solved by the Invention] However, the stage device has the following drawbacks.

First, as a fixing method after positioning, positioning control using an interferometer can be performed, but for this purpose, it is necessary to constantly energize the motor, which is the drive unit, and the motor itself becomes a heat source. Then, the heat of the motor, which is a heat source, is transmitted to each member of the stage device, causing deformation, making it impossible to accurately position the wafer.

For example, if the distance between the wafer 1 and the mirror 59 changes due to the deformation of the X stage 52, the interferometer cannot measure the amount, so the wafer 1 shifts by the amount of change.

Second, since it has a three-stage structure in which a drive section and a guide section are provided in each of the XYθ directions, it becomes a very large structure.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and it is an object of the present invention to provide a stage device that is not affected by thermal deformation, is capable of highly accurate positioning control, and has a compact structure.

[Means and effects for solving the problem] In order to achieve the above object, according to the present invention, a plurality of ultrasonic motors are arranged in a plane and the thrust and direction of the traveling waves generated from each ultrasonic motor are controlled. , it is possible to simultaneously drive XYθ on the same plane.

[Embodiment] Fig. 1, Fig. 2, Fig. 3, and Fig. 4 show a first embodiment of the present invention, in which Fig. 1 is a perspective view, Fig. 2 is a plan view, and Fig. 3 is a perspective view.
The figure is a front view, and FIG. 4 is a block diagram. In the figure, 1 is a wafer, 2 is a wafer mounting table on which the wafer 1 is placed, and 3
4 is a stage top plate that fixedly supports the wafer mounting table 2;
-1 is an ultrasonic motor for moving the stage top plate 3 in the X direction; 4-2 is an ultrasonic motor that is paired with the ultrasonic motor 4-1 and is for moving the stage top plate 3 in the X direction; 5-1 is an ultrasonic motor for moving the stage top plate 3 in the Y direction; 5-2 is an ultrasonic motor paired with the ultrasonic motor 5-1 and is used to move the stage top plate 3 in the Y direction; 6 is a base fixed This is a stage board corresponding to a board, and the ultrasonic motor is fixedly supported. A permanent magnet 7 is fixed to the stage substrate 6 and pulls the stage top plate 3. 8 is a reference mirror fixedly supported on the stage top plate 3; 9-1 is a laser interferometer for measuring the position of the stage top plate 3 in the X direction; 9-2
9-3 is a laser interferometer for measuring the position of the stage top plate 3 in the Y direction and the θ direction; 10-1 is a driver that drives the ultrasonic motor 4-1; and 10-2 is the ultrasonic motor 4. -2 driver driving 10-
3 is a driver 10 that drives the ultrasonic motor 5-1
-4 is a driver that drives the ultrasonic motor 5-2; and 11 is a controller that controls the positioning of the stage top 3 based on external commands. Here, the ultrasonic motor 4.5 is described in "Japanese Patent Publication No. 1-17353" and "
This part has a function equivalent to the part that generates the driving force of the ultrasonic mortal device described in Japanese Patent Publication No. 1-17354, and generates traveling waves in respective predetermined directions with respect to the stage top plate 3. This is an actuator that is driven by friction, and the friction contact surface with the stage top plate 3 uses only one linear part of the driving force generating surface by the traveling wave of the ultrasonic motor, and the other driving force generating surface The stage top plate 3 is elevated due to a minute difference in height, and the driving force generating surface described above does not come into contact with the stage top plate 3.

Next, the operating state of stage movement in the above configuration will be described. First, when the ultrasonic motor 4.5 is in a non-energized state, that is, when no high-frequency voltage is applied to the electrostrictive element, the stage top plate 3 is pressed against the ultrasonic motor 4.5 by its own weight and the magnetic force of the permanent magnet 7. It is fixed to the stage substrate 6 by the frictional force generated. Next, when the ultrasonic motor 4 is energized to generate a traveling wave, a thrust is generated in the ultrasonic motor 4 to move the stage top plate 3 in the X direction. At the same time, the ultrasonic motor 5
``Unexamined Japanese Patent Publication No. 59-101608j''
-106886 Publication”, “Japanese Unexamined Patent Publication No. 59-107369”
By generating a standing wave, the frictional force between the stage top plate 3 and the ultrasonic motor 5 is reduced as described in the above publication. This causes the stage top plate 3 to move in the X direction. Similarly, the ultrasonic motor 4 has a standing wave,
By generating a traveling wave in the ultrasonic motor 5, the stage top plate 3 is moved in the Y direction. By the way, the stage top plate 3 does not have a guide to regulate the direction of movement.
Simply causing the ultrasonic motor 4 to generate a traveling wave and the ultrasonic motor 5 to generate a standing wave to move the stage top plate 3 in the X direction does not necessarily move the stage top plate 3 in the correct direction.

In other words, it has a Y-direction component and a rotational component due to various factors such as the machine difference between each ultrasonic motor, the horizontality of the friction surface between the stage top 3 and the ultrasonic motor 4.5, and the position of the center of gravity of the stage top 3. (The stage top plate 3 does not move in the correct direction due to the generated thrust). (The rotational component here is
It is a component whose center of rotation is a direction perpendicular to the Y direction, and this direction is hereinafter referred to as the θ direction. ) Here, the controller 10 detects the amount of movement in the Y direction and the θ direction using the laser interferometers 9-2 and 9-3, and instructs the ultrasonic motor 5, which was generating the standing wave, to cancel the amount of movement mentioned above. By giving a command to the drivers 10-3 and 10-4 to generate a traveling wave, correction is made so that the stage top 3 moves accurately in the X direction.

For the θ direction, ultrasonic motor 4-1.4-2
．． 5-1. The traveling directions of the traveling waves of the opposing motors in 5-2 are opposite directions and in the same direction, that is, the direction in which the four ultrasonic motors generate thrust to rotate the stage top plate 3 in the θ direction. By generating a traveling wave, the stage top 3 rotates in the θ direction. Therefore, by controlling the traveling waves of the four ultrasonic motors mentioned above, the stage top 3 can be rotated not only during rotational motion, but also during rotational motion. Even the position of the center of rotation can be freely controlled. In other words, in response to external commands and signals from the laser interferometer 9, the controller 11 controls the ultrasonic motor 4-1.4-2.5-1.5-2.
By controlling the direction and thrust of the traveling wave generated by the driver through the driver, it is possible to position the restage top plate 3, that is, the wafer 1, in the X direction, Y direction, and θ direction.

5, 6 and 7 show a second embodiment of the present invention, FIGS. 5(a), 5(b) and 7(c) are partial detailed views for showing the piezoelectric element, The figure is a plan view, and FIG. 7 is a front view. In the figure, reference numeral 20 denotes four ultrasonic motors that are attached to the stage top plate 3 and generate thrust by traveling waves against the stage substrate 6, and each of the four ultrasonic motors is placed at a position where it generates thrust in a direction perpendicular to its neighbor. has been done.

21 is a permanent magnet that is attached to the stage top plate 3 and attracts the stage substrate 6 and the stage top plate 3; 22 is a plurality of piezoelectric elements; and 23 is a wave that travels on the surface due to ultrasonic vibrations generated by the piezoelectric element 22. Elastic body that causes 24
is the surface of the elastic body 23, which is a part that causes a traveling wave to cause movement in an object that comes into contact with pressure, and is a tapered part. The other configurations are the same as those of the first embodiment. Next, the operation of moving the stage in the above configuration will be described. As in the first embodiment, the stage top plate 3 is moved in the direction, and the θ direction, and the above movements are possible at the same time. Further, the absolute position of the stage top plate 3 with respect to the stage substrate 6 can be measured by the laser interferometer 9, and the positioning of the stage top plate 3 can be controlled by feeding back the measured value to the ultrasonic motor 20. Here, in the first embodiment, the ultrasonic motor was attached to the stage substrate 6, whereas in this embodiment, the ultrasonic motor was attached to the stage top plate 3. This leads to the first
In the embodiment, there was a problem that the movement stroke was restricted due to the size of the stage top plate 3.
Position control becomes possible as long as the beam of the laser interferometer does not deviate from the reference mirror 8 for position measurement. That is, the first
This is because, in the embodiment, a problem arises in that the stage top plate 3 comes off from the ultrasonic motor. Furthermore, in this example, there was only one set of movable parts on the stage top plate side, but by attaching an ultrasonic motor to the stage top plate 3 side, it is possible to install multiple movable parts on the same stage board. be. As a result, for example, when the stage device of this embodiment having two sets of movable parts is used in a semiconductor manufacturing equipment, one of the movable parts performs positioning control and performs a predetermined process, which is the original purpose of the semiconductor device. During this time, the other movable part can exchange wafers, making it possible to improve the throughput of semiconductor manufacturing equipment.

8 and 9 show a third embodiment of the present invention, with FIG. 8 being a plan view and FIG. 9 being a front view.

In the figure, 1 is a wafer, 2 is a wafer mounting table on which the wafer 1 is placed, 3 is a stage top plate that fixedly supports the wafer mounting table 2, 6 is a stage substrate corresponding to a base surface plate, and 8 is a stage substrate. The reference main body 9-1 is fixedly supported on the stage top plate 3. Reference numeral 9-1 is a laser interferometer for measuring the position of the stage top plate 3 in the X direction. a laser interferometer for measuring the direction and position in the θ direction; 30 is a driving plate connected to the stage top plate 3 via a leaf spring 31; 31 is a leaf spring that is restrained in the XYθ directions and elastically deformed in the Z direction; 32 is an air pocket provided on the stage substrate 6 for moving the stage top plate 3 in two directions, 33 is an air inlet provided on the stage substrate 6, and 34 is an ultrasonic motor attached to the drive plate 30. be. Next, the operation of moving the stage in the above configuration will be described. As in the first embodiment, the four ultrasonic motors generate standing waves or traveling waves, and by controlling the traveling direction of the traveling waves and the generated thrust, the driving plate 30 is moved, and the plate spring Stage top plate 3 via 31
is movable in the X direction, Y direction, and θ direction, and the above movements are possible simultaneously. Further, the absolute position of the stage top plate 3 with respect to the stage substrate 6 can be measured by the laser interferometer 9, and the above measured value is transferred to the ultrasonic motor 34.
The positioning control of the stage top plate 3 becomes possible by feedback control.

Here, since the stage substrate 6 and the ultrasonic motor 34 are in contact with each other, the flatness of the stage substrate 6 causes the drive plate 30 to
will move in the Z direction. If the drive plate 30 and the stage top plate 3 are connected as a rigid body, the wafer 1 will also move in the Z direction. This embodiment adds a mechanism for correcting such Z-direction movement. (It may be intentionally moved in the Z direction.) For example, as in this embodiment, the driving plate 30 and the stage top plate 3
If these are connected by a leaf spring 31 that is restrained in the XYθ directions and elastically deformed in two directions, the stage top plate 3 can be moved in the Z direction. Here, for example, if pressure-controlled air is introduced into the air pocket 32 from the air injection port 33 as in this embodiment, the stage top plate 3 can be moved to a predetermined position in two directions.

Furthermore, in this embodiment, the plurality of air pockets 32 can be used as a leveling mechanism for the stage top plate by filling each with pressure-controlled air, and although not shown, the position in the Z direction can be adjusted. By adding a measuring sensor to this embodiment and feeding back the measured value to the air pressure control section, accurate two-drive can be performed.

[Effects of the Invention] As explained above, by arranging a plurality of ultrasonic motors in a plane and controlling the thrust and direction of the traveling waves generated by each ultrasonic motor, a guide mechanism is not required and the structure is small (especially thin). XYθ stage is possible. In addition, since the above-mentioned stage maintains its position without generating any heat when stopped after positioning, a high-precision stage that is less susceptible to thermal deformation is possible. Furthermore, by using a stage device having a plurality of movable parts to which ultrasonic motors are attached, high throughput can be achieved.

[Brief explanation of drawings]

Fig. 1 is a perspective view of the first embodiment of the present invention, Fig. 2 is a plan view thereof, Fig. 3 is a front view thereof, Fig. 4 is a block diagram thereof, and Figs. 5(a) and (b). , (c) are the pressures used in the second embodiment of the present invention! A top view, a front view, and a side view of the element, FIG. 6 is a plan view of the second embodiment, FIG. 7 is a front view thereof, FIG. 8 is a plan view of the third embodiment, and FIG. 9 is a plan view of the second embodiment. Its front view and FIG. 10 are perspective views of the conventional example. 1: Wafer, 2: Sea urchin mounting table, 3: Stage top plate, 4.5: Ultrasonic motor 6: Stage board, 7, Permanent magnet, 8: Reference mirror 9: Racer interferometer, 10 Driver 11: Controller 20: Ultrasonic motor 21: Permanent magnet, 2 3 4 0 1 2 3 4: Electrostrictive element, Bielastic body, : Part of Taber, : Drive plate, : Leaf spring, : Air pocket, : Air inlet, : ultrasonic motor

Claims (6)

[Claims] (1) A plurality of ultrasonic motors that generate traveling wave-like ultrasonic vibrations on the surface of an elastic body to move an object in pressure contact with the surface in one direction, and move the object in at least two directions. 1. A stage device using an ultrasonic motor, characterized in that the stage device is arranged at a position where the ultrasonic motor is moved, and is equipped with means for controlling thrust and direction by traveling waves generated from the plurality of ultrasonic motors. (2) A stage device using an ultrasonic motor according to claim 1, wherein thrust generating surfaces of the plurality of ultrasonic motors are arranged on the same plane. (3) Arranging the plurality of ultrasonic motors according to claim 1 so that the direction of the thrust is square, and controlling the thrust and direction of the traveling waves generated from the plurality of ultrasonic motors. A stage device using an ultrasonic motor, which moves and positions a moving object in the XYθ directions. (4) A plurality of ultrasonic motors according to claim 1 are attached to a moving object, and the thrust generating surfaces of the plurality of ultrasonic motors come into pressurized contact with the same plane on the fixed side of the moving object. A stage device that uses an ultrasonic motor and is characterized by moving and positioning the stage in the XYθ directions. (5) A stage device using the ultrasonic motor as set forth in claim 4, characterized in that a plurality of moving objects to which a plurality of ultrasonic motors as set forth in claim 4 are attached are arranged. . (6) In a stage device in which a moving object to which a plurality of ultrasonic motors that generate thrust by traveling waves are attached moves on the same plane on the fixed side, the mounting portions of the plurality of ultrasonic motors and the moving object are mounted on the same plane. 5. A stage device using an ultrasonic motor according to claim 4, wherein the stage device is mounted with a degree of freedom only in a direction perpendicular to the stage device.