JPH04256534A - Fine movement x-y stage - Google Patents

Abstract

PURPOSE:To heighten natural oscillation frequency by asymmetrically arranging flat springs relative to an axis in the X axial direction or an axis in the Y axial direction. CONSTITUTION:A stage 1A is supported by way of arranging plate type elastic plates 4X, 4Y, 5X, 5Y having flexibility in the bending direction at the angle of 90 deg. on an X axis and Y axis plane so that each of the elastic plates 4X, 4Y, 5X, 5Y respectively shows flexibility in the X axis direction and the Y axis direction, and the X axis elastic plates 4X, 5X having flexibility in the X axis direction are driven in the Y axis direction. Further, the elastic plates 4X, 4Y, 5X, 5Y are asymmetrically arranged relative to at least one of the axes in the Y axis direction and the X axis direction on a fine movement X-Y stage moving to a position for the purpose of a stage by driving the Y axis elastic plates 4Y, 5Y having flexibility in the Y axis direction in the X axis direction.

Description

Description: FIELD OF THE INVENTION The present invention relates to a fine movement X-Y stage that is mounted on a coarse movement X-Y stage having a large movable range to perform precise positioning. [0002] When manufacturing semiconductor devices such as integrated circuits,
An XY stage used for positioning requires high positioning accuracy. The higher the degree of integration and density of semiconductor devices, the higher the required accuracy, and for example, positioning accuracy on the order of 0.01 μm is required. [0004] The X-
As a Y stage, the inventors have already published Unexamined Japanese Patent Publication No. 1-107
We have proposed a fine movement X-Y stage disclosed in Japanese Patent No. 188, and have obtained excellent results. The present invention has been accomplished in order to further improve the positioning accuracy of the fine movement XY stage disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 1-107188. [Prior Art] (1) Configuration FIG. 7 is a diagram illustrating the configuration of a fine movement XY stage.
(a) is a perspective view of the fine movement X-Y stage, (b) is (a
) is a diagram showing the coordinates of . That is, the pillar 2- of the fine movement X-Y stage
1, 2-2, 2-3, and 2-4 are fixed to a coarse movement X-Y stage (not shown in the figure) below them. [0008]The pillars 2-1, 2-2, 2-3,
2-4 is connected to the sub-stage 3 via leaf springs 4X and 4Y.
Supports X-1, 3X-2, 3X-3, 3X-4. Furthermore, sub-stages 3X-1, 3X-2,
3X-3 and 3X-4 support the stage 1 via leaf springs 5X and 5Y. On the other hand, the actuators that drive the stage 1 are piezoelectric elements 6, 7, and the driving force (pressing force) of the piezoelectric elements 6, 7 is applied to the sub-stages 3X-2, 3X-3, and the plate springs 5X, Stage 1 is driven and moved via 5Y. [0011] Furthermore, the plate springs 4X, 4Y, 5X, 5Y
exhibits flexibility in the bending direction, so the piezoelectric element 6 is generated by aligning the leaf springs 4X, 4Y, 5X, and 5Y in the X-axis direction and the Y-axis direction as shown in FIG. A driving force in the Y-axis direction and a driving force in the X-axis direction generated by the piezoelectric element 7 can be transmitted to the stage 1. (2) Operation Figure 8 is a plan view explaining the operation. (a) is a diagram showing the steady state of the fine movement X-Y stage, and (b) is a diagram when the stage is driven in the Y-axis direction. Diagram explaining (c)
is a diagram explaining the case where the stage is driven in the X-axis direction, (
d) is a diagram showing the coordinates of (a), (b), and (c). Note that the cross-hatched portions in the figure indicate the pillars, the stage, and the sub-stage. That is, when the piezoelectric element 6 extends and a driving force is applied to the sub-stage 3X-2, as shown in FIG. 8(b), the leaf springs 4X, 5X do not deform, but the leaf springs 4Y, 5
Y is bent, and the stage 1 moves slightly in the Y-axis direction (upward in the figure). Similarly, when the piezoelectric element 7 extends and a driving force is applied to the sub-stage 3X-3, as shown in FIG. 8(c), the leaf springs 4Y and 5Y do not deform, but the leaf spring 4X
, 5X are bent, and the stage 1 moves slightly in the X-axis direction (to the left in the figure). Therefore, if the two piezoelectric elements 6 and 7 extend simultaneously, the stage 1 can be moved simultaneously in the X-axis direction and the Y-axis direction, and the stage 1 can be moved to a desired position. In order to determine the position of the stage 1 with high precision, a high precision position detector is required, and the position of the stage 1 is generally measured using a laser interferometer or the like. Then, based on the measurement results, the piezoelectric elements (actuators) 6 and 7 are controlled in a closed loop (feedback control).
Control and drive using. [0017] Incidentally, in order to improve positioning accuracy in closed-loop positioning control, it is necessary to increase the loop gain and at the same time widen the frequency band of the closed-loop control system. However, when the lowest natural vibration frequency of the fine movement XY stage is low, the phase delay becomes large in the high frequency region, making it easy to cause oscillation in the closed loop control system.
Positioning controllability deteriorates. That is, there is a problem in that the frequency band of the closed loop control system is limited by the lowest order natural vibration frequency of the fine movement XY stage, making it impossible to perform high-speed positioning. FIG. 9 is a plan view illustrating the lowest natural vibration mode. Note that the cross-hatched portions in the figure indicate the pillars, the stage, and the sub-stage. That is, the lowest natural vibration mode is a mode in which the stage 1 vibrates in the rotational direction. In other words,
Leaf springs 4X, 4Y, 5X, 5Y shown in this mode
This occurs because the spring constant of is the smallest, and a clear center of rotation is formed in the stage 1 by the leaf springs 4X, 4Y, 5X, and 5Y that support the stage 1. On the other hand, stage 1 has piezoelectric elements 6 and 7
There is also a translational mode that vibrates in the drive direction of , that is, the X-axis direction and the Y-axis direction, but the dominant spring constant in this mode is the spring constant of the piezoelectric elements 6 and 7.
Leaf springs 4X, 4Y, 5X, 5Y in the rotation mode
is much larger than the spring constant of , and therefore the resonant frequency (natural vibration frequency) is also high. However, depending on the inertia of the stage targeted for the rotation mode, there may be cases where the rotation mode is not necessarily the lowest order. By mounting a mirror for a laser interferometer for position measurement on the stage 1, the inertia of the stage 1 increases, and the natural vibration frequency of the rotation mode further decreases. The technical problem of the present invention is that the conventional fine movement
By solving the above-mentioned problems on the stage,
- By increasing the lowest natural vibration frequency of the Y stage, the frequency band of the control system can be increased to realize a fine movement XY stage that performs high-speed positioning. [Means for Solving the Problems] FIG. 1 is a diagram illustrating the basic principle of the present invention. Note that the cross-hatched portions in the figure indicate the pillars, the stage, and the sub-stage. The present invention provides plate-shaped elastic plates 4X, 4Y, 5X.
, 5Y are arranged asymmetrically with respect to the axis in the X-axis direction and the axis in the Y-axis direction. In the present invention, the elastic plates 4X, 4Y, 5X, and 5Y, which are flexible in the bending direction, are arranged so that they are flexible in the X-axis direction and the Y-axis direction, respectively. The stage is supported by being arranged at an angle of 90° in the axial plane, and the X-axis elastic plates 4X and 5X, which are flexible in the X-axis direction, are driven in the Y-axis direction to form Y-axis elastic plates 4Y and 5Y. bend the
In addition, Y-axis elastic plates 4Y and 5Y having flexibility in the Y-axis direction
The present invention assumes a fine movement X-Y stage based on the principle of driving the X-axis in the X-axis direction to deflect the X-axis elastic plates 4X, 5X, and as a result, move the stage to a target position. Specifically, the configuration is as follows. ■Pillars 2-1 and 2-2 aligned in the X-axis and Y-axis directions and fixed at positions corresponding to the four corners of the square
, 2-3A, and 2-4 are provided. ■ Adjacent said pillars 2-1, 2-2, 2-3A, 2 so as to constitute the four sides of the square of said ■.
Four sub-stages 3X-1, 3X-2A, 3X-3A, and 3X-4 are supported and arranged between the stages 4 and 4 via elastic plates 4X and 4Y. ■Four sub-stages 3X-1, 3 of ■
Within the frame constituted by X-2A, 3X-3A, 3X-4,
Each sub-stage 3X-1, 3X-2A, 3X-3A, 3
Main stage 1 from X-4 via elastic plates 5X, 5Y
Support and arrange A. ■In order to drive and move the main stage 1A to the desired position, the main stage 1A is moved through the Y-axis elastic plate 5Y.
Of the two sub-stages 3X-1 and 3X-3A that support A, one sub-stage 3X-3A is driven in the X-axis direction by the actuator 7A, and supports the main stage 1A via the X-axis elastic plate 5X. Two sub-stages 3X-2A, 3
One sub-stage 3X-2A of X-4 is driven in the Y-axis direction by an actuator 6A. [0033] Then, the slight movement X- consisting of the above ■~■
This is a fine movement X-Y stage in which elastic plates 4X, 4Y, 5X, and 5Y are arranged asymmetrically with respect to the axis in the Y-axis direction or the axis in the X-axis direction. [Operation] By arranging the elastic plates 4X, 4Y, 5X, and 5Y asymmetrically with respect to the axis in the Y-axis direction or the axis in the X-axis direction, when the main stage 1A is about to rotate, the The symmetry between the main stage 1A and the elastic plates 4X, 4Y, 5X, and 5Y is lost, and a clear center of rotation no longer occurs. [0035] Therefore, vibration due to the rotational mode is less likely to occur and the natural vibration frequency becomes high. That is, it becomes possible to increase the frequency band of the feedback control system, and the positioning time becomes shorter. [Example] Next, how the fine movement XY stage of the present invention can be practically implemented will be explained using an example. (1) Example-1 1) Configuration Figure 2 is a diagram explaining Example-1, (a) is a perspective view explaining the basic configuration, and (b) shows the coordinates of (a). Figure. In this embodiment, the difference from the conventional fine movement XY stage shown in FIG. 7 is that the plate springs 4X, 4Y, 5X
, 5Y. Furthermore, by changing the arrangement position, stage 1a and sub-stage 3X-2
a, 3X-3a, and the shape of the pillar 2-3a is also changed. That is, the leaf spring 4 connected to the pillar 2-3a
X, 4Y positions and secondary stages 3X-2a, 3X-3
The positions of leaf springs 5X and 5Y connected to stage 1a are different from that of stage 1a. [0040]Furthermore, the leaf springs 4X, 4Y in this embodiment
, 5X, 5Y are arranged and configured asymmetrically with respect to the X and Y axes. By the way, all leaf springs 4X, 4Y, 5X
, 5Y are parallel to the X-axis direction or the Y-axis direction. 2) Operation Figure 3 is a plan view illustrating the operation. (a) is a diagram showing the steady state, (b) is a diagram showing the case of driving in the Y-axis direction, and (c) is ( It is a figure which shows the coordinate of (a) and (b). Note that the cross-hatched portions in the figure indicate the pillars, the stage, and the sub-stage. That is, the basic operation is the same as that of the conventional example shown in FIG. The driving force is transmitted to the stage 1a via
The 12 leaf springs 4Y, 5Y are deformed, and the stage 1a
moves slightly in the Y-axis direction. [0044] Furthermore, the piezoelectric element 7 which is a drive source in the X-axis direction
When the stage 1a extends, the stage 1a similarly moves slightly toward the X axis. As a result, the stage 1a can be moved to the desired position. In addition, all leaf springs 4X, 4Y
, 5X, 5Y are parallel to the X-axis direction or the Y-axis direction, the leaf spring 4X generated as the stage 1a is driven
, 4Y, 5X, 5Y are the same in each axial direction, and no difference occurs depending on the arrangement position of the leaf springs 4X, 4Y, 5X, 5Y. 3) Analysis FIG. 4 is a diagram illustrating an example of mode analysis by simulation, in which (a) is a diagram showing the conventional example, and (b) is a diagram showing the present embodiment. Note that the cross-hatched portions in the figure indicate the pillars, the stage, and the sub-stage. That is, FIG. 4 shows the conditions for performing a simulation using the finite element method, and the dimensional data L1 to L30 shown in the figure were determined as follows. a. In case of conventional example b. In the case of the example L1 20 mm
L11 20 mm L21
20mm L2 10mm
L12 10mm
L22 10 mm L3 20
0 mm L13 200 m
m L23 140 mm L
4 10mm L14
10 mm L24 10 mm
L5 20mm
L15 20mm L25
80mm L6 20mm
L16 20mm
L26 20 mm L7 10
mm L17 10 mm
L27 10mm L8
200mm L18
200mm L28 140mm
L9 10mm
L19 10mm L29
10 mm L10 200 mm
L20 20mm
L30 80mm LXT 260
mm LYT 260 mm The thickness of leaf springs 4X, 4Y, 5X, 5Y is 0.
It was set to 4mm. That is, the outer dimensions were the same as a 260 mm square, and only the placement positions of the leaf springs 4X, 4Y, 5X, and 5Y were changed. Table 1. shows the simulation results. [Table 1] Table 1. As you can see, the leaf spring 4X,
The natural vibration frequency when 4Y, 5X, and 5Y are arranged symmetrically is 426Hz, and when arranged asymmetrically,
961 Hz, indicating that excellent results can be obtained. By the way, the leaf springs 4X, 4Y, 5X, 5Y
When arranged asymmetrically, the rotational inertia of the stage 1a is also increased by 0.62 times, and the reduction in the inertia also improves the natural vibration frequency of the rotational mode. Furthermore, since the improvement ratio of the natural vibration frequency due to the reduction in inertia is inversely proportional to the 1/2 power of the inertia ratio, the natural vibration frequency due to the reduction in inertia is determined by the following equation (1). 426×(1/0.62)1/2≒426×1.2
7≒541Hz ----------(1) In other words, the improvement ratio of the natural vibration frequency is 1.
It is 27. On the other hand, the natural vibration frequency obtained in the simulation is 961 Hz, and the improvement ratio is 2.2.
It is 6. That is, although the natural vibration frequency increases due to the reduction in the inertia of the stage 1a, its influence is small, and the natural vibration frequency is greatly improved by asymmetrically arranging the leaf springs 4X, 4Y, 5X, and 5Y. (2) Example-2 FIG. 5 is a diagram explaining Example-2, in which (a) shows the fine movement
- A perspective view of the Y stage, (b) is a diagram showing the coordinates of (a). In this example, Example-1 shown in FIG.
The only difference is the method of transmitting the driving force of the actuator. That is, the displacement direction converting mechanisms 8a, 8b
is used to change the direction of the driving force of the piezoelectric elements 6a and 7a to 9
0°, and the driving force is applied to sub-stages 3X-2a and 3X-3.
This configuration is such that it joins stage 1a and stage 1a. [0062] In such a configuration, the piezoelectric elements 6a, 7a
This is an effective way to reduce the size of the entire device when the length of the device becomes long. The operation is the same as in Example-1. (3) Other embodiments Figure 6 is a diagram explaining other embodiments, (a) (b)
(c) is a diagram showing variations in the arrangement position of the leaf spring, and (d) is a diagram showing the coordinates of (a), (b), and (c). Note that the cross-hatched portions in the figure indicate the pillars, the stage, and the sub-stage. That is, (a) is an example in which the leaf springs 4X, 4Y, 5X, and 5Y are arranged asymmetrically with respect to the axis in the Y-axis direction, and symmetrically with respect to the axis in the X-axis direction. Further, (b) and (c) are examples in which the leaf springs 4X, 4Y, 5X, and 5Y are arranged asymmetrically with respect to the axes in the Y-axis direction and the X-axis direction. [0066] As described above, according to the fine movement X-Y stage of the present invention, the leaf spring (plate-like elastic plate) can be moved asymmetrically with respect to the axis in the X-axis direction and the axis in the Y-axis direction. The natural vibration frequency can be increased by arranging it. Therefore, it is possible to increase the frequency band of the closed loop control system that performs positioning and drive control of the stage, and the positioning error and positioning time of the control system can be reduced. As a result, positioning accuracy is high, and
A stable fine-movement X-Y stage capable of high-speed positioning can be realized.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the basic principle of the present invention.

FIG. 2 is a diagram illustrating Example 1, in which (a) is a perspective view illustrating the basic configuration, and (b) is a diagram showing the coordinates of (a).

[Fig. 3] Plan views explaining the operation, (a) is a diagram showing a steady state, (b) is a diagram showing the case of driving in the Y-axis direction, (c) is a diagram of (a) and (b). It is a diagram showing coordinates.

FIG. 4 is a diagram illustrating an example of mode analysis by simulation, in which (a) is a diagram showing a conventional example, and (b) is a diagram showing the present embodiment.

[Fig. 5] A diagram explaining Example-2, (a) shows the slight tremor
- A perspective view of the Y stage, (b) is a diagram showing the coordinates of (a).

FIG. 6 is a diagram explaining other embodiments, (a) and (b)
(c) is a diagram showing variations in the arrangement position of the leaf spring, and (d) is a diagram showing the coordinates of (a), (b), and (c).

[Fig. 7] A diagram explaining the configuration of the fine movement X-Y stage.
(a) is a perspective view of the fine movement X-Y stage, (b) is (a
) is a diagram showing the coordinates of .

FIG. 8 is a plan view explaining the state of fine movement, (a) is a diagram showing the steady state of the fine movement X-Y stage, (b) is a diagram explaining the case when the stage is driven in the Y-axis direction, (c )
is a diagram explaining the case where the stage is driven in the X-axis direction, (
d) is a diagram showing the coordinates of (a), (b), and (c). Note that the cross-hatched portions in the figure indicate the pillars, the stage, and the sub-stage.

FIG. 9 is a plan view illustrating the lowest-order natural vibration mode.

[Explanation of symbols]

1, 1A, 1a, 1b, 1c, 1d
Stage (main stage) 2-1, 2-2a
Pillar 2-2
Pillar 2
-3, 2-3A, 2-3a, 2-3b
Pillars 2-4, 2-4a, 2-4b
Pillar 3X-1, 3X-1a
Sub stage 3
X-2, 3X-2A, 3X-2a, 3X-2b, 3X-
2c Secondary stage 3X-3, 3X-3A,
3X-3a, 3X-3b, 3X-3c, 3X-3d Secondary stage 3X-4, 3X-4a, 3X-4b
Secondary stage 4X, 4Y
, 5X, 5Y Elastic plate (plate spring) 6, 6a, 7, 7a
Piezoelectric element (piezoelectric actuator)

Claims (3)

[Claims] Claim 1: Plate-shaped elastic plates (4X, 4Y, 5X, 5Y) having flexibility in the bending direction are arranged along the supporting the stage arranged at a 90° angle in the axial plane;
X-axis elastic plate with flexibility in the X-axis direction (4X, 5X)
The fine movement The Y stage has fixed pillars (
2-1, 2-2, 2-3A, 2-4), and the adjacent pillars (2-1, 2-2, 2-3A, 2-4) are provided so as to constitute the four sides of the square.
-1, 2-2, 2-3A, 2-4) between elastic plates (4X,
4Y) through four sub-stages (3X-1, 3X-
2A, 3X-3A, 3X-4), and supports and arranges the four sub-stages (3X-1, 3X-2A, 3X-3A).
, 3X-4), each of the sub-stages (3
The main stage (1A) is supported and arranged from the is one of the two sub-stages (3X-1, 3X-3A) that support the main stage (1A) via an elastic plate (5Y) having flexibility in the Y-axis direction.
3X-3A) in the X-axis direction with an actuator (7A), and two sub-stages (1A) supporting the main stage (1A) via an elastic plate (5X) having flexibility in the X-axis direction.
3X-2A, 3X-4), one of the substages (3X-2A, 3X-4)
X-2A) is driven in the Y-axis direction by the actuator (6A), and as a result, the sub-stages (3X-1, 3X-2A,
The main stage (1
In the fine movement X-Y stage that moves A) to the target position, elastic plates (4X, 4Y,
5X, 5Y) are arranged asymmetrically. 2. In the fine movement X-Y stage according to claim 1, the elastic plates (4X, 4Y, 5X, 5Y) are arranged asymmetrically with respect to the axis in the Y-axis direction and the axis in the X-axis direction. Features fine movement X-Y stage. 3. In the fine movement X-Y stage according to claim 2, the elastic plates (4X, 4Y, 5X, 5Y) are arranged asymmetrically with respect to the axis in the Y-axis direction and the axis in the X-axis direction, and The axis (α
) The elastic plates (4X, 4Y, 5X, 5Y) are arranged symmetrically with respect to the secondary stage (3X-2A, 3X-
3A) is configured so that the driving force of the actuator (6A, 7A) is applied to the
stage.