JPH0413532A - Rotation/translation stage - Google Patents

Abstract

PURPOSE:To realize a high precision with use of a compact structure by driving a rotor directly attached to a stage, thereby to cause the stage to make its rotating motion and, on the other hand, supporting the stage with a plurality of parallel leaf springs so as to enable the stage to make its displacing motion in the axial direction of the motor, thereby to cause the stage to make its displacing motion. CONSTITUTION:A boss 10 is fixed on the underside of a chuck plate 1. A lower diaphram 3 is formed with openings at its symmetrical positions. Through these openings there are disposed fixed legs 11 for supporting a stator 5 of a motor. A rotor 4 of the motor is attached to the boss 10 so as to oppose the stator 5. A Hall element is disposed in the vicinity of the rotor 4. When the Hall element detects the angle of rotation of a permanent magnet to supply an electric current of controlled phase to a stator coil 5, a rotating force is imparted. Then, the chuck plate 1 makes its THETA-indicated rotating motion relative to a housing 7. The housing 7 is provided, at its lower portion, with a gas supply passage over which a bellows 8 is mounted. A gas is supplied through the gas supply passage to extend the bellows 8, thereby raising the boss 10 from a lower side thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a device for positioning a workpiece, and more particularly to a device for positioning in two degrees of freedom: translation and rotation around the translational direction.

[Prior art] Semiconductor manufacturing equipment, such as step exposure equipment! In this system, a semiconductor wafer to be processed is delivered to a chuck plate or the like, and the semiconductor wafer is fixed by suction with a chuck, and various operations such as step exposure and honding are performed.

Rotational errors occur during the delivery of semiconductor wafers.

In other words, from the orientation flat or from a given direction,
For example, it tilts by a little less than 1 degree.

In addition, semiconductor wafers have variations in thickness in the thickness direction, depending on the specification and variations within the specification.The latter is about several tens of μm, and the former is about 400 μm to 800 μm depending mainly on the diameter.

The stage of semiconductor exposure equipment and ion implantation equipment consists of - A coarse movement mechanism for moving the semiconductor wafer to perform work on each chip or multiple chips on a boat, and a stage for making fine adjustments at each work position. Has a fine movement mechanism.

The above-mentioned angular errors and thickness variations during the delivery of semiconductor wafers are too large to be adjusted by a fine movement mechanism.

If the adjustable range of the fine movement mechanism is expanded, the accuracy will be reduced, so a stage or the like must have an adjustment mechanism in the θ direction and the Z direction with appropriate accuracy.

Note that once this error in semiconductor wafer delivery is corrected, there is no need to correct it again for that semiconductor wafer.

FIGS. 2(A), (B), and <C> show examples of the θ2 adjustment mechanism according to the prior art. FIG. 2(A) shows a cross-sectional view in the contraction direction, and FIG. 2(B) shows a sectional view in the θ direction. FIG. 2(C) is a plan view of the θ stage that performs the adjustment, and shows a centering cam mechanism that performs the adjustment in the Z direction.

In FIG. 2(A), a chuck plate 51 attracts a semiconductor wafer using vacuum, electrostatic force, or the like. The position of this chuck plate 51 is adjusted in two directions by three eccentric cams 53. As shown in an enlarged view in FIG. 2(C), the eccentric cam mechanism includes, for example, an eccentric cam 5 having an oval planar shape.
3 is rotated by a servo motor 52. The height of the upper end of the eccentric cam 53 changes depending on the rotation angle of the eccentric cam 53. By changing the rotation angle of the three eccentric cams 53, the tilting can also be adjusted.

A cam mechanism consisting of an eccentric cam 53 and a servo motor 52 is arranged on the θ stage 55.

A spring 54 is attached between the chuck plate 51 and the θ stage 55, and provides a return force to the chuck plate 5. This tin ring 54 can be omitted in the case of a horizontal stage, but cannot be omitted in the case of a vertical stage.

The θ stage 55 has an arm 5 as shown in FIG. 2(B).
7 is attached, and a linear motor 56 is provided in the orthogonal direction so as to push this arm 57. The linear motor 56 can be configured by, for example, converting the rotation of a motor into linear motion using a screw or the like. The arm 57 is pulled by a spring 58 in order to apply a return force to the θ stage 55.

The θ stage 55 is rotatably supported on a base 60 via a bearing 59. fixed base 60
The θ stage 55 performs in-plane rotation relative to the θ stage 55, and the chuck plate 51 displaces in the height direction relative to the θ stage 55. In this manner, θZ force direction movement can be performed.

[Problem to be solved by the invention J] In the prior art shown in FIG.
It has a two-tiered structure. Further, the driving of each stage includes friction between parts. This makes the structure complicated, making it difficult to increase precision, and configuring a vertical stage requires additional guides and drive mechanisms.

It is an object of the present invention to provide a rotary translation stage which is compact in structure, can achieve high precision, and is also suitable for vertical stages.

[Means for Solving the Problems] According to the present invention, motion having two degrees of freedom, rotational and translational, is performed on a single stage. A rotor of a motor is attached directly to the stage, and the rotor is driven directly to the stator to perform rotational movement, and the stage with the rotor attached is supported by a plurality of parallel plate spring members.
The stage member is provided with a driving means that enables the motor to be displaced in the axial direction and drives the stage member in the axial direction, so that the axial displacement can be performed again.

[Function] A rotational drive mechanism and a translational drive mechanism are combined on an integrated stage, and one stage can move in two degrees of freedom.One rotation is performed by a direct drive motor without using a speed reducer. Because of this, there is less friction and no debris such as bala crash in the speed reduction mechanism, making it possible to achieve high accuracy.

Further, since the stage member supported by the parallel plate spring member is driven in the axial direction of the motor, the stage is suitable for a vertical stage structure, and the accuracy of translational movement can be easily increased.

[Example code] FIG. 1 shows a rotary translation device according to an embodiment of the present invention.

The chuck plate 1 is used to place a semiconductor wafer on its upper surface, and can move in two directions as shown and in the θ direction. On the bottom surface of the chuck plate 1 is a phosphatide 10.
is fixed. This hoss 10 is supported by two parallel diaphragms 2.3, which are fixed to the inner member 6a of the bearing 6. The bearing 6 has an outer member 6b and an inner member 6.
a and a ball bearing 6C, and its displacement in the height direction is restricted by a mechanism (not shown), and it has only a degree of freedom in the rotational direction. The outer member 6b of the bearing is fixed to the housing 7. Note that the lower diaphragm 3 is provided with openings at symmetrical positions, and fixed legs 11 are disposed through these openings to support the stator 5 of the motor.

The rotor 4 of the motor is placed on the boss 1 so as to face the stator 5.
It is attached on 0. For example, the stator 5 is composed of a permanent magnet, and the rotor 4 is composed of a coil. In this configuration, the commutator is provided on the boss 10, and the coil 4
t flow is supplied to the Conversely, the rotor 4 may be a permanent magnet and the stator 5 may be a coil. In this configuration, a Hall element is provided near the rotor 4, and a current having a controlled phase is supplied to the stator coil 5 by detecting the rotation angle of the permanent magnet of the rotor 4. When the rotational force is applied in this way, the chuck plate 1 moves in the θ direction relative to the housing 7. Note that the θ direction movement is limited to, for example, about ±1 degree, and the lower diaphragm 3 The position of the fixed leg 11 can be changed within the provided opening. Note that the rotation angle can be increased by placing the motor and diaphragm in separate locations. A waste supply hole is provided in the lower part of the housing 7, and a bellows 8 is attached above the waste supply hole. That is, the structure is such that when the bellows 8 is extended by supplying gas from the opening, the boss 10 can be pushed up from below. Note that a spherical rotation hinge 9 is arranged between the bellows 8 and the boss 10. Therefore, the boss 10 can perform rotational movement relative to the bellows 8. Note that a sliding bearing or the like may be used in place of the spherical rotating hinge. When the boss 10 is pushed up via the bellows 8 or the rotating hinge 9, the tire flam 2-3 becomes flat with low rigidity in two directions. , the boss 10 is elastically deformed and displaced in two directions.

That is, the parallel tire flange 2.3 plays the role of a parallel link. Note that instead of using a disc-shaped tire flam, a cross-shaped, star-shaped, etc. radial leaf spring can also be used. Further, the bearing for allowing rotation of the housing 10 and the tire flamm 2.3 may be of any type other than a ball bearing, for example, a leaf spring connecting the housing 7 and the inner member 6a in the radial direction. It can also be configured.

An arm 12.14 is attached to the chuck plate 1t and projects outward. A displacement detector 13 in the θ direction is arranged to face the arm 12, and a displacement detector 15 in two directions is arranged to face the lower surface of the arm 14.
is located. These displacement detectors are, for example, capacitance type-rji type.

The rotation-translation device shown in Fig. 1 has a #I structure that directly drives the stage 1 in two directions and in the θ direction, and has a compact structure. , there are fewer places where sliding friction can occur, making it easier to improve accuracy.

FIG. 3 is a block diagram showing an example of a control system of the rotation-translation device shown in FIG. 1.

A case will be explained in which displacement in two directions is detected and control is performed.

The high pressure gas supplied from the waste source 21 is passed through the filter 22
The gas is then turned into medium-pressure gas through the regulator 23, and into gas at a desired pressure through the electropneumatic regulator 24.

This gas is supplied to the bellows 8 to drive the chuck plate in two directions. The displacement of the chuck plate in the Z direction is detected by the position detector 25, and the sensor amplifier 26
is supplied to a comparator 28 of the control device 27 via.

Desired two-direction positions are set within the control device 27, and the set values and the measured values from the sensor amplifier 26 are compared by the comparator 28. A control signal for how to change the gas pressure based on the comparison result is supplied to the amplifier 29, and a signal from the two amplifiers or the electropneumatic regulator 2 is supplied to the amplifier 29.
4 to change the gas pressure and correct the Z-direction position of the chuck plate.

It should be noted that although the explanation has been made regarding the case of position control in two directions, control in the θ direction can also be performed in the same manner. In this case, the position detector detects the angle in the θ direction, and the control signal controls the current flowing through the motor coil.

FIG. 4 shows a rotary translation device according to another embodiment of the present invention. In this embodiment, three bellows 8a, 8b, 8c are arranged under the boss 10, and a spherical rotary hinge 9a, 9b, respectively. The lower surface of the boss 10 is pressed by 9c. The rest of the structure is the same as the embodiment shown in FIG.

In the embodiment of FIG. 4, there are three bellows 8a, 8b.
, 8c, the tilting of the chuck plate 1 can also be adjusted.

FIG. 5 shows a rotary translation device according to another embodiment of the invention.

In this embodiment, a piston member 30 is attached to the lower surface of the boss 10, and a cylinder member 32 is formed on the bottom surface of the housing 7. Further, an O-ring 31 is attached to a part of the piston member 30, and the piston member 30
and the cylinder member 32 to form an airtight seal. By supplying gas into the cylinder member 32 from the lower surface of the housing 7, the piston member 30 is pushed upward. In this way, driving in two directions is performed.

FIG. 6 shows a rotary translation device according to another embodiment of the invention.

In this embodiment, the O-ring 31 in the embodiment of FIG. 5 is removed. That is, a gap is formed between the cylinder member 32 and the piston member 30, and air in the lower space 33 escapes to the upper part through this gap. That is, an air bearing 34 is formed by the piston member 30 and the cylinder member 32. Other points are first
This is similar to the embodiment shown in the figure.

In this embodiment, the slip r due to the O-ring in the case of the embodiment shown in FIG. Since J-rubbing is eliminated, it is easy to achieve high accuracy. However, since it is not an airtight structure, it is not possible to make the first part of the space a vacuum.

In the embodiments described above, translation and rotation are possible, and after the chunk plate is positioned at a proper position, it is necessary to apply servo until the work is completed. In this case, heat is generated in the actuator such as the direct drive motor, which may adversely affect the positioning accuracy of the stage. In addition, actuators using gas pressure cannot be made very high in the same property.

FIG. 7 shows a rotation translation locking device according to another embodiment of the invention.

FIG. 7(A) shows the structure of the chuck plate 1. The chuck plate 1 has a locking mechanism 16 thereunder, and a boss 10 is attached below the locking mechanism 16. As shown in an enlarged view of a portion of the locking mechanism 16 in FIG. 7(B), the piezoelectric actuator 35 has one end held by a support member 37, the other end facing the housing side, and supported by a parallel link 36. Press the locking shoe 38. The parallel link 36 has parallel elastic members 36a and 36b, and is elastically deformed in response to a force in the direction of the arrow. When the piezoelectric actuator 35 extends in the direction of the arrow, the parallel link 36 is elastically deformed and the locking shoe 38 comes into contact with the inner wall of the housing 7 . When the force generated by the piezoelectric actuator 35 becomes sufficiently high, the locking shoe 38 comes into strong contact with the inner wall of the housing 7 and locks by friction. After positioning, the chuck plate 1 is locked at that position. The other configurations are the same as the configuration shown in FIG.

Although the case where a disc-shaped chuck plate 1 is used has been described, the shape of the chuck plate 1 is not limited to a circular shape.

FIG. 8 is a plan view schematically showing a rotary translation device according to another embodiment of the present invention.

In this embodiment, the chuck plate 1 and the housing 7 have a rectangular cross section. The post 10 supporting the lower part of the chuck plate 1 also has a rectangular cross section and is connected to the intermediate member 44 by a cross-shaped parallel leaf spring 42. boss 10
The intermediate member 44 has a length in the direction perpendicular to the plane of the drawing, and a plurality of leaf springs 42 are stacked to form a parallel link structure. Further, the space between the intermediate member 44 and the housing 7 is supported by a leaf spring member 46 extending in a direction perpendicular to the plane of the paper. That is, the structure is such that the leaf spring 46 allows rotational movement, and the leaf spring 42 allows translational movement. The driving method may be the same as that shown in Fig. 1.

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

[Effects of the Invention] According to the present invention, a stage such as a chuck grate can be directly driven in two directions and in the θ direction, and can be driven in two directions with a compact structure.
Axial movement is achieved.3 Also, there are fewer slidingly engaged parts, making it easier to achieve high precision.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a rotary translation device according to an embodiment of the present invention, and FIGS. 2 (A), (B), and (C) show examples of the prior art,
Figure 2 (A) is a joint sectional view, Figure 2 (B) is a schematic plan view of the θ stage, Figure 2 (C) is a front view and side view showing the eccentric cam, and Figure 3 is the same as Figure 1. A block diagram showing an example of a control system of the embodiment; FIGS. 4, 5, and 6 are cross-sectional views showing other embodiments of the present invention, and FIGS. 7(A) and (B) are diagrams of the present invention. 7(A) is a sectional view showing the configuration, FIG. 7(B) is a partially enlarged view thereof, and FIG. 8 is a schematic plan view showing another embodiment of the present invention. be. In the figure: 2.3 12.14 13.15 Chuck plate Tire flam Rotor Stator Bear link housing Bellows Rotating hinge Boss Fixed leg Arm Displacement detector Locking mechanism Gas source Filter regulator Electro-pneumatic regulator Position detector Sensor Amplifier Controller Comparator Amplifier Piston member 0 ring Cylinder member Lower space Air bearing Piezoelectric actuator Parallel link support member Locking shoe Parallel leaf spring member Intermediate member Leaf spring member Patent applicant Sumitomo Heavy Industries, Ltd. Sub-agent Patent attorney Keishi Takahashi (A) m cross section (B) θ stage (C) Eccentric cam Example of conventional technology Figure 2 - Figure 4 33: Lower space 34: Air bearing 16: Lock mechanism (A) Configuration (B) Partially enlarged view Other examples Whistle 7P ;A

Claims (4)

[Claims] (1) a stage member for placing an object; a rotor of a motor attached to the stage member; a stator of the motor disposed opposite to the rotor; a stator of the motor attached to the stage member and the A rotation device comprising: a plurality of parallel leaf spring members that allow displacement of the motor in the axial direction; a bearing member that rotatably supports the parallel leaf spring members; and a translation drive means that drives the stage member in the axial direction of the motor. translation stage. (2), further, one end is fixed to the stage member;
2. The rotation translation stage according to claim 1, further comprising a locking mechanism including a plurality of piezoelectric actuators whose other ends are moved by an applied voltage, and a fixing member facing the other ends of the piezoelectric actuators. (3) The rotation translation stage according to claim 1 or 2, wherein the translation drive means includes a bellows that expands and contracts in the axial direction and a means for supplying gas into the bellows. (4) The rotation translation stage according to claim 1 or 2, wherein the translation drive means includes a cylinder member and a piston member that are movable relative to each other in the axial direction, and a means for supplying gas into a space created by the cylinder member and the piston member. .