JP2773777B2 - Actuator unit and stage device capable of level adjustment using the same - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator capable of driving a stage device and a stage device capable of adjusting a level using the actuator, and particularly to a high-precision stage such as a semiconductor manufacturing device. The present invention relates to an actuator suitable for a device and a stage device capable of adjusting a level using the actuator.

In recent years, for example, in the field of semiconductor integrated circuits, the required processing accuracy has been further improved along with the improvement of the degree of integration. In order to realize a narrower line width, the subject of research and development has shifted to an exposure apparatus that uses an electron beam or X-ray as a light source instead of ultraviolet light. Accordingly, it is necessary to improve the accuracy of the driving stage. For example, 0.25 to 0.
To achieve a line width of 3 μm, an alignment (alignment) accuracy of about 0.05 μm is required, and to achieve this, a drive stage of about 0.005 μm is required, and at least 0.01 μm is required.

Such a high-precision XYZ drive stage is for example 150 to 20
It is required to move at a speed of 0 mm / sec.

Such a drive stage device must be able to adjust the level, for example, to dispose the photosensitive film within the depth of focus of the incident beam. As the diameter of a semiconductor wafer increases, it is necessary to refocus a number of times within one wafer in accordance with the warpage, thickness distribution, inclination, and the like of the wafer.

[Prior Art] Conventional XYZ drive stage devices and the like mainly use an actuator that combines a DC motor and a ball screw. However, due to backlash, backlash, etc., the driving accuracy is generally limited to about 0.1 μm, and 0.01 μm.
It is difficult to obtain an accuracy of m or less.

A driving stage device using a linear motor as a driving force source is also known. It is difficult for a linear motor to achieve a position accuracy of 0.01 μm or less.

On the other hand, an XY drive device using a piezoelectric element as an actuator unit has been proposed. Piezoelectric elements are good at producing minute displacement, but it is difficult to increase the absolute value of the displacement.

Therefore, it is advantageous to combine coarse movement and fine movement in order to perform high-precision driving.

It has also been proposed to stack the drive stage devices in several stages and perform coarse movement and fine movement in each axial direction and each rotational direction.

In these conventional drive stage devices, the axis of the actuator is provided in a direction perpendicular to the driven body, and applies a driving force to the driven body by pushing or pulling the driven body. When adjusting the Z direction level of the stage body defining the XY plane, the stage body is driven by an actuator having an axis along the Z direction. When the axial length of the actuator is large, the size of the entire stage device is considerably large.

The driven body moves on a guide member such as a guide surface or a guide rail provided on the support. For example, a guide member for holding the stage movably in the X direction and an X stage including an X-direction drive source are configured, and then a guide member and a Y-direction drive source for holding the entire X stage movably in the Y direction , And a Z stage having a guide member and a drive source for further moving the Y stage in the Z direction is configured. Further, rotation stages of θx, θy, and θz are added as needed. When the coarse movement and the fine movement are performed separately in each direction, the number of these steps is doubled.

[Problems to be Solved by the Invention] As described above, according to the related art, in order to adjust the level of a half-surface stage device, an actuator having an axial direction perpendicular to a plane is used. Had a large volume.

In addition, it is difficult to obtain high accuracy with a simple configuration, and if high accuracy is to be obtained, the entire apparatus becomes larger.

In addition, when the number of stages of the drive stage device increases, the number of members interposed between the drive source and the driven body increases, and the driving force generated by the drive source due to the play between the members and the like is applied to the driven body. It will be inaccurate how much is transmitted.

Further, when the driven body moves on the guide portion of the support,
The driving load increases due to friction when moving, and the position accuracy and the responsiveness deteriorate.

An object of the present invention is to provide an actuator unit suitable for a high-precision drive stage device.

Another object of the present invention is to provide an actuator unit that uses an actuator having an axial direction in the XY plane and exerts a driving force in the Z direction.

Another object of the present invention is to provide a high-precision drive stage device. Another object of the present invention is to provide a small-stage drive stage device having a high degree of freedom.

[Means for Solving the Problems] According to the present invention, a first shaft having an axis arranged along an XY plane is provided.
The first wedge member is moved in the axial direction by displacing the actuator in the XY plane direction within the wedge structure, and the second wedge structure is moved in the Z direction substantially orthogonal to the XY plane through the connection of the wedge surfaces. Move to

In the present specification, the XY directions refer to directions orthogonal to each other in an arbitrary plane such as a stage surface. Also, Z
The direction refers to a direction orthogonal to any of the XY directions.

1A and 1B schematically show two basic embodiments of the present invention.

For example, referring to FIG.
The first wedge structure 5 is mounted on the support surfaces 2a and 2b of the first wedge. The first wedge structure 5 has end faces 4a and 4b at both ends in the axial direction. The actuator 3 changes its axial length by a given signal, and the end faces 4a and 4b.
b, fixed to and supported on the support surfaces 2a, 2b of the base 2 and having first symmetrical wedge surfaces 6a, 6b on opposite sides. On top of this first wedge structure 5, first symmetric wedge surfaces 6a, 6b
A second wedge structure 9 having a second symmetric wedge surface 8a, 8b substantially parallel to the second wedge structure 9 is arranged, coupled and supported.

Preferably, between the support surfaces 2a, 2b of the base 2 and the first wedge members 7a, 7b, and between the first symmetric wedge surfaces 6a, 6b of the first wedge members 7a, 7b and the second wedge. An adhesive layer is provided between the structure 9 and the second symmetric wedge surfaces 8a, 8b.

In the configuration of FIG. 1 (A), the first wedge member
7a, 7b have a wedge surface which narrows towards the second wedge structure 9, whereas the second wedge structure 9 has a wedge surface which extends towards the first wedge structure. .

FIG. 1B shows a form in which these inclinations are reversed. That is, the second wedge structure 9 has a wedge surface that narrows downward, and the first wedge structure 5 has a wedge surface that expands upward.

The second wedge structure 9 is connected to the driven body 1 such as a stage, and drives the driven body 1 with respect to the base 2.

Further, according to the present invention, there are provided a base 2 having a support surface, a driven body 1 having a stage surface, and three actuator units arranged between the base 2 and the driven body 1. The actuator unit has two end faces 4a and 4b at both ends in the axial direction. The actuator 3 changes its axial length by a given signal, and is fixed to both end faces 4a and 4b of the actuator. Support surface 2
a first wedge structure 5 comprising first wedge members 7a, 7b coupled and supported on a, 2b and having opposing first symmetric wedge surfaces 6a, 6b; Second symmetric wedge surfaces 8a, 8b substantially parallel to the symmetric wedge surfaces 6a, 6b
And a second wedge structure coupled and supported on the first wedge structure. The second wedge structure 9 is substantially orthogonal to the support surface due to the axial expansion and contraction of the actuator 3. An actuator unit that can be displaced in a direction in which the stage surface moves relative to the supporting surface by operating the three actuator units.

Preferably, the driven body 1 has high rigidity in the axial direction,
Elastic link part 10 having low rigidity in the direction perpendicular to the axis
And the actuator.

[Operation] When the actuator 3 expands and contracts in the axial direction in the XY plane, the first wedge members 7a and 7b are driven in the axial direction, and the wedge surfaces 6a and 6b move so as to separate or approach in the axial direction. . As the wedge surfaces 6a and 6b move, the second wedge structure 9 having the wedge surfaces 8a and 8b engaged with the wedge surfaces 6a and 6b becomes X
It is displaced in the Z direction orthogonal to the Y plane.

In FIG. 1 (A), when the actuator 3 contracts, the first wedge members 7a and 7b having wedge surfaces narrowing upward move inward, and the wedge surface 6a and the wedge surface 8a of the second wedge structure 9 are moved. And also between the wedge surface 6b and the wedge surface 8b. Then, in order not to form a gap, the second wedge structure 9 having a wedge surface opened downward moves downward in the figure. Conversely, when the actuator 3 extends, the second wedge structure 9 having the wedge surface opened downward moves upward so as to be pushed. Thus, the displacement in the Z direction orthogonal to the XY plane is generated by the axial displacement of the actuator having the axis in the XY plane.

In FIG. 1 (B), when the actuator 3 contracts, the first wedge members 7a and 7b having the wedge surfaces expanding upward move inward. The wedge surfaces 6a and 6b sandwich the wedge surfaces 8a and 8b of the second wedge structure 9 from both sides, and the second wedge structure 9 is lifted upward. Conversely, when the actuator 3 is extended, the wedge surfaces 6a and 6b opened upward move away from each other, and the second wedge structure 9 having the wedge surface narrowing downward moves downward.

In this way, an actuator unit that converts an axial displacement of an actuator having an axis in the XY plane into a displacement in the Z direction is obtained.

Assuming that the inclination angle of the wedge surface is θ, the displacement z in the Z direction caused by the displacement x in the XY plane is z = x · tan θ.

Accordingly, by selecting the angle θ, the displacement amount x of the actuator can be enlarged or reduced and converted into the displacement z in the Z direction.

If an adhesive layer is provided between the sliding surfaces, the adhesive layer is easily sheared and deformed.

By using three or more sets of the actuator units, the Z level of the stage can be adjusted, and the stage can be rotated around the X axis and the Y axis.

When three or more actuator units are driven by the same amount, the driven body 1 moves in parallel in the Z direction.

By making the displacement amounts of the three actuator units different, rotation about the X axis and rotation about the Y axis can also be performed. Therefore, by adjusting the amount of displacement of each actuator unit, any Z, θX, and θY movement can be performed.

If there is a difference in the drive amount of each actuator unit, a bending moment is generated in each actuator unit.

These bending moments can be absorbed by supporting the driven body via the elastic link portion 10 having high rigidity in the axial direction and low rigidity in the direction perpendicular to the axis.

That is, since the elastic link portion 10 has a low rigidity in a direction perpendicular to the axis, it is easily deformed in a direction perpendicular to the axis when it receives a force. Thereby, interference between the actuator units can be reduced.

In addition, since the reaction force at the time of driving is small, the stress applied to the driven body 1 is also small, and the occurrence of internal distortion can be suppressed.

Furthermore, play of the coupling portion is eliminated by coupling with the elastic link portion 10, and the driven body can be driven with high accuracy.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

2 (A) to 2 (D) show an actuator unit. 2 (A) is an axial sectional view of the actuator unit, FIG. 2 (B) is a side view of the actuator unit, FIG. 2 (C) is a plan view of the actuator unit,
FIG. 2D is a partially enlarged view of the actuator unit.

Referring to FIG. 2A, the actuator elements 13a and 13b, which are piezoelectric elements, are stored in storage cases 24a and 24b, respectively. The storage cases 24a and 24b are fixed to the slide wedge bodies 17a and 17b by bolts or other appropriate methods. Further, as shown in FIG. 2 (B), the storage cases 24a and 24b are
The actuator elements 13a and 13b, which are piezoelectric elements, are tightened by an appropriate means such as 25 to apply an appropriate preload. Therefore, the actuator elements 13a, 13b, the storage cases 24a, 24b, and the slide wedge bodies 17a, 17b are integrally connected to form the first wedge structure 5. The slide wedge bodies 17a and 17b have slide surfaces 15a and 15b on the lower surface, and have inclined slide surfaces 16a and 16b on the upper surface. These slide surfaces 16a and 16b have symmetrical inclination angles left and right in the figure.

The first wedge structure 5 is mounted on an actuator base 12 having sliding surfaces 12a and 12b. When the actuator elements 13a, 13b expand and contract, the slide wedge bodies 17a, 17b are displaced so as to move away from or approach each other.

A second wedge structure 9 is placed on the first wedge structure 5. On the lower surface of the second wedge structure 9, the wedge surfaces 16a, 1b of the slide wedge bodies 17a, 17b are provided.
Wedge surfaces 18a and 18b facing 6b are formed. That is, wedge surfaces 16a and 18a are arranged in parallel, and wedge surfaces 16b and 18b are also arranged in parallel. Slide wedge body
When the members 17a and 17b are displaced away from each other, the wedge surfaces 18a and 18b of the second wedge structure 9 are displaced upward by the pressing force. Conversely, when the slide wedge members 17a, 17b are displaced in a direction approaching each other, the second wedge structure 9
Wedge surfaces 18a and 18b are displaced downward so as to be attracted.

Slide wedge bodies 17a, 17b and actuator base
12 and between the slide wedge members 17a, 17b and the second wedge structure 9 may be mere sliding contacts, but preferably, as shown in FIG. Combined by 27,29. The adhesive layers 27 and 29 are formed of a thin adhesive layer having a thickness of, for example, 100 to 500 μm. The adhesive layers 27 and 29 are formed of, for example, epoxy resin. For example, the actuator elements 13a and 13b, which are piezoelectric elements,
When an axial displacement of about 40 μm occurs, the second wedge structure 9 is configured to generate a Z-direction displacement of about 10 to 20 μm. The adhesive layer has low resistance to shear deformation but high resistance to compression. Therefore, when the slide wedge body 17 is about to be displaced, it easily undergoes shearing deformation and the second
Is driven in the vertical direction in the figure.

The upper surface of the second wedge structure 9 is provided with an elastic link portion 20 integrally formed. The elastic link portion 20 has a cylindrical shape with a reduced diameter. That is, the elastic link portion 20
Has sufficient rigidity in the axial direction, but has low rigidity in the direction perpendicular to the axial direction. The elastic link portion 20 further continues to the fastening portion 21.

As shown in FIG. 2 (C), for example, 4
Two screw holes are formed to receive the bolts 22a, 22b, 22c, 22d. The driven body 1 is fastened by these bolts
Fixed to 21.

When a plurality of driving force sources are coupled to the driven body 1, the elastic link portion 20 is used when another driving force source applies a driving force.
It is provided to allow displacement by the driving force. That is, when a force is applied from the side, the elastic link portion 20 bends to allow the driven body 1 to be displaced.

When the driven body 1 is driven by a single actuator unit, the elastic link portion 20 is not necessarily required.

FIGS. 3A and 3B show two structural examples of the elastic link portion. FIG. 3A shows a cylindrical elastic link portion 20a as shown in FIG. 2A. When the driven body 11 moves in the vertical direction in the figure, the elastic link portion 20a allows the displacement by bending and deforming in the vertical direction.
When the second wedge structure 9 moves in the left-right direction in the drawing, the elastic link portion 20a has sufficient rigidity in the axial direction, and thus drives the driven body 11 in the left-right direction.

FIG. 3B shows another example of the structure of the elastic link portion.
The elastic link portion 20b is a rigid portion 30 having a relatively large diameter.
And spherical hinge-shaped hinge portions 31 and 32 whose diameter gradually decreases from both sides toward the center. When the driven body 11 is displaced in the in-plane direction, the hinge portions 31 and 32 change the coupling angle to allow the displacement. When the second wedge structure 9 is displaced in the left-right direction in the figure, the hinge portions 31, 32 have sufficient rigidity to drive the driven body 11 in the left-right direction. Although the case where a pair of hinge portions 31 and 32 are provided at both ends of one rigid portion 30 is shown, a structure having a plurality of rigid portions with a hinge portion interposed therebetween may be used.

FIGS. 4A and 4B show a stage device capable of level adjustment.

FIG. 4A is a schematic top view showing the base structure 35.
The stage body 40 is above the actuator units 39a to 39
e, only supported by 39g.

As shown in the cross section of FIG. 4B, the base structure 35 has a concave portion on its upper surface, and the stage body 40 is
Has a convex portion 41 corresponding to the concave portion. The concave portion of the base structure 35 is defined by the bottom surface 36 and the side surface 37 and the like, and is separated from the surface 42 of the convex portion 41 of the stage body 40 by a predetermined gap 43.

In the plan view of FIG. 4 (A), as indicated by a broken line,
Below the stage body 40, three Z-axis direction actuator units 39a, 39b, 39c are arranged at positions corresponding to the vertices or the center of each side of the equilateral triangle. Also, three actuator units 39d, 39e, and 39 having axes parallel to the respective sides are provided on three sides of each side of the stage body 40.
g is located. Each actuator unit has an actuator base fixed to the base structure 35 and an elastic link member fixed to the stage body 40. Actuator units 39a, 39b, 39c control three degrees of freedom of displacement in the Z-axis direction and rotation around the X-axis and around the Y-axis. In addition, three actuator units 39
d, 39e, and 39g are rotations in the X-axis direction, Y-axis direction, and XY plane.
Controls one degree of freedom. Note that a configuration in which four or more actuator units in the Z-axis direction are provided may be employed.

The actuator unit 39a in the Z-axis direction shown in FIG. 4 (B) is the same as that shown in FIGS. 2 (A) to 2 (D). The actuator base 12 is fixed to the base structure 35 by bolts 45, and the fastening portion 21 is fixed to the stage body 40 by bolts 22. When the second wedge structure 9 is vertically displaced in the drawing, the fastening portion 21 is driven via the elastic link portion 20, and the stage body 40 is vertically driven.

The actuator units 39d, 39e, and 39g in the XY direction have elastic link members along the axial direction of the actuator. In the case of this stage configuration, the actuator displacement amounts 39d, 39e, and 39g determine the stage displacement amounts X, Y, and θz in a complicated manner. When these displacements occur in the XY plane, the elastic link portions 20 of the actuator units 39a, 39b, 39c in the Z-axis direction allow the displacement by causing bending.

It should be noted that the base structure 35 shown in FIGS.
Is mounted on a coarse movement stage device to form an XYZ stage device having a desired drive span.

 FIG. 5 schematically shows a control system.

Rotation θz of driven body 1 in X and Y directions and XY plane
Are provided with three distance measuring systems 50, 60a, and 60b. For example, a system 50 for monitoring the position of the driven body 1 in the X direction includes a mirror 59, a laser light source 51, a beam splitter 53, a mirror 55, and a light receiver 57 on the driven body 1, and receives incident laser light. The position of the mirror 49 in the X direction is measured by counting the interference fringes between a part of the laser beam 52 and the reflected laser beam 54.

A first Y direction monitor system 60a including a laser light source 61a and a light receiver 67a, and a second Y direction monitor system 60b including a laser light source 61b and a light receiver 67b also measure the position of the mirror 69 in the Y direction according to the same principle. . By measuring the Y-direction position at two locations, the angle θz of the mirror 69 in the XY plane can also be measured.

In addition, another monitor system including the camera 80 is provided, and is configured to capture a planar image of the driven body 1 and perform positioning in the XY plane.

Further, three capacitance sensors 7 are provided on the back surface of the driven body 1.
1, 73, and 75 are provided, and the position in the Z direction is measured at three points. From these results, the position in the Z direction, rotation around the X axis, and rotation around the Y axis can be measured.

Output signals of these monitor systems are input to the control circuit 85. After the comparison with the target set value or the like, a correction signal is sent from the control circuit 85 to the piezoelectric actuator or the like.

Although the embodiments have been described above, the present invention is not limited to these embodiments. For example, various modifications, improvements,
It will be obvious to those skilled in the art that combinations and the like are possible.

[Effects of the Invention] As described above, according to the present invention, a driving force can be exerted in a direction orthogonal to the axial direction of the actuator element.

Since the dimension in the driving force direction can be reduced, the size of the stage device capable of level adjustment can be reduced.

Further, by adjusting the wedge surface angle, the displacement of the actuator element can be enlarged or reduced.

By driving one stage body in various directions, it is possible to simplify the configuration of the entire stage device capable of level adjustment.

[Brief description of the drawings]

1A and 1B are conceptual diagrams of an actuator unit using a wedge according to a basic embodiment of the present invention, and FIGS. 2A to 2D are diagrams showing an actuator unit according to an embodiment of the present invention. 2 (A) is a longitudinal sectional view, FIG. 2 (B) is a side view, FIG. 2 (C) is a plan view, FIG. 2 (D) is a partially enlarged sectional view, FIG. FIGS. 4A and 4B are perspective views showing two structural examples of an elastic link portion. FIGS. 4A and 4B are views showing a stage device capable of level adjustment according to the embodiment. FIG. 4A is a plan view, FIG. 4B is a sectional view taken along line IVB-IVB, and FIG. 5 is a schematic block diagram of a control system. In the drawing, 1... A driven body 2... A base 2 a, 2 b... A support surface 3... An actuator 4 a, 4 b ... an end face 5 ... a first wedge structure 6 a, 6 b. Wedge surface 7a, 7b First wedge member 8a, 8b Second symmetric wedge surface 9 Second wedge structure 10 Elastic link portion 12 Actuator base 13 Actuator element 17 Slide wedge body 16, 18 Wedge surface 20 Elastic link part 21 Fastening part 24 Storage case 27, 29 Adhesive layer 35 Base structure 39 Actuator unit 40 … Stage body

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-193089 (JP, A) JP-A-63-120047 (JP, A) JP-A-63-7175 (JP, A) 100290 (JP, U) 60-91891 (JP, U) 1-74597 (JP, U) 63-693 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) B23Q 1/00-1/76 B23Q 5/28 H01L 21/68 H02N 2/00

Claims (4)

(57) [Claims] 1. A base having a support surface, a piezoelectric element having two end faces at both ends in the axial direction, the length of which in the axial direction is changed by a given signal, and fixed to both end faces of the piezoelectric element; A first wedge surface coupled and supported on a support surface of the base and having a first symmetric wedge surface on an opposite side;
And a second symmetric wedge surface substantially parallel to the first symmetric wedge surface, and coupled and supported on the first wedge structure. The first symmetric wedge surface narrows toward the second wedge structure, and the second wedge structure is expanded and contracted in the axial direction of the piezoelectric element. Is an actuator unit that is displaced in a direction substantially perpendicular to the axial direction. 2. The actuator unit according to claim 1, further comprising an adhesive layer between the support surface and the first wedge member, and between the first wedge surface and the second wedge surface. . 3. A base having a support surface, a driven body having a stage surface, and three or more actuator units disposed between the base and the driven body, wherein each of the actuator units comprises: A piezoelectric element having two end faces at both ends in the axial direction and changing its axial length by a given signal;
A first wedge structure fixed to both end faces of the piezoelectric element, coupled to and supported on a support surface of the base, and having a first wedge member having a first symmetric wedge surface on the opposite side; A second substantially parallel to the first symmetric wedge surface
A second wedge structure coupled and supported on the first wedge structure;
The first symmetric wedge surface narrows toward the second wedge structure, and the second wedge structure is displaced in a direction substantially orthogonal to the support surface due to axial expansion and contraction of the piezoelectric element. A stage device, comprising: an actuator unit capable of adjusting a level and a tilt of the stage surface with respect to the support surface by operating the three actuator units. 4. The stage device according to claim 3, wherein each of said actuator units has an elastic link portion having high rigidity in an axial direction and low rigidity in a direction perpendicular to the axis.