JPH01222310A - Fine device - Google Patents

Abstract

PURPOSE:To prevent the warp of a table so as to attain precise displacement by making the dimension of parallel deflection beam displacement devices in a displacement direction almost equal to the dimension of a table more than the dimension of a member for displacement. CONSTITUTION:The dimension in the direction of an X-axis can considerably be increased without altering the dimension of the parallel beam in the direction of an Y-axis in displacement devices 22Fxa and 22Fxb including overhang parts 22a and 22b to which the table is fixed. Similarly, the dimension in the direction of the Y-axis can considerably be increased without altering the dimension in the direction of the X-axis in the parallel warp beam displacement devices 23Fya and 23Fyb including overhang parts 23a and 23b. Even if the dimension of the connection parts 25a and 25b connecting the table are considerably increased and the member for displacement, becomes large, the table mounting the member can be constituted in such a way that it will not considerably protrude from the connection parts 25a and 25b in the direction of the X-axis. Thus, the deflection of the table and furthermore, the warp of the member for displacement can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to semiconductor manufacturing equipment, electron microscopes, alignment devices,
The present invention relates to a fine movement mechanism used in a device that requires adjustment on the sub-μm order, such as a mask pattern inspection device.

[Conventional technology]

In recent years, in various technical fields, there has been a demand for devices capable of fine displacement adjustment on the order of sub-μ groups. Typical examples are semiconductor manufacturing equipment such as mask aligners and electron beam lithography equipment used in the manufacturing process of LSIs (Large Scale Integrated Circuits) and VLSIs. These devices require fine positioning on the order of sub-μm, and as the positioning accuracy improves, the degree of integration also increases, making it possible to manufacture high-performance products.

Such fine positioning is not limited to the above semiconductor devices,
It is also necessary for various high-magnification optical devices such as electron microscopes, alignment devices, mask pattern inspection devices, etc., and improving its accuracy will contribute to the development of cutting-edge technologies such as biotechnology and space exploration. (contribute)

An excellent fine movement mechanism for performing such fine positioning has been proposed. This fine movement mechanism will be explained with reference to the drawings. FIG. 3 is a perspective view of the fine movement mechanism, in which 1 is a central rigid body part 1 made of a highly rigid member, 2a is an overhanging part extending from the central rigid body part 1 in the Y-axis direction, and 2b is a central rigid body part 1. 3a is an overhanging portion that overhangs in the direction opposite to the overhanging portion 2a, 3a is an overhanging portion that overhangs from the central rigid body portion 1 in the X-axis direction, and 3b is an overhanging portion that overhangs from the central rigid body portion 1 in the opposite direction to the overhanging portion 3a. 4a and 4b are the overhanging parts 2a and 2, respectively.
Fixing portions 5a and 5b provided at the lower end of the end portion b and fixed to a suitable base are table connecting portions provided at the upper end of the end portions of the overhang portions 3a and 3b and connecting the table 6, respectively. A member to be displaced (a member to be displaced) is placed on the table 6 . Overhanging parts 2a, 2b, 3a, 3b,
Fixed parts 4a, 4 bs and table connecting parts 5a, 5b
are each made of the same material as the central rigid body part 1, and are processed and formed together with the central rigid body part 1 from one block.

2F, , 2F, b are parallel flexure beam displacement mechanisms (the parallel flexure beam displacement mechanisms will be described later) configured in the overhanging parts 2a and 2b, respectively, and are configured symmetrically with respect to the central rigid body part 1. has been done.

The parallel deflection beam displacement mechanisms 2F, , 2FXb work together to
A translational displacement in the axial direction (displacement in the axial direction of the central rigid body portion lOX) is generated. 3F, □ 3F, b are respective overhanging parts 3a
, 3b, and are constructed symmetrically with respect to the central rigid body portion l. Parallel deflection beam displacement mechanism 3F, □3F9. work together to generate a translational displacement in the Y-axis direction (displacement of the central rigid body portion l in the Y-axis direction). The above parallel deflection beam displacement mechanism 2FX, 2Fxb, 3
Fy□ 3Fy& is each overhang 2a, 2b, 3a, 3b
It is constructed by forming a predetermined through hole at a predetermined location.

The parallel flexible beam displacement mechanism 2F, includes two mutually parallel flat flexible beams 11 formed by forming a through hole 10, and protrudes from the central rigid body part l and the overhanging part 2a into the through hole 10. It is composed of a piezoelectric actuator 12 mounted between protrusions, and a strain gauge G attached to a predetermined location of a flexible beam 11. The other parallel deflection beam displacement mechanisms 2F-b, 3Fym, and 3Fyb have similar configurations. The configuration and operation of the parallel deflection beam displacement mechanism are disclosed in, for example, Japanese Patent Laid-Open No. 61-209846.

Next, the operation of this fine movement mechanism will be explained. Now, when an equal voltage is applied to each piezoelectric actuator 12 of the parallel flexible beam displacement mechanism 2F, , 2F, b, the parallel flexible beam 11
is deformed according to the applied voltage, and the fine movement mechanism is translated in the X-axis direction. This displacement corresponds to the central rigid body part 1, the parallel flexible beam displacement mechanisms 3F□, 3F, and the table connecting parts 5a, 5b.
and the table 6 is translated by the same amount in the X-axis direction. Similarly, when the same voltage is applied to the piezoelectric actuators 12 of the parallel deflection beam displacement mechanisms 3Fy□ 3Fyb, the table 6 is translated in the Y-axis direction. Note that by driving these parallel deflection beam displacement mechanisms simultaneously, a combined translational displacement can be obtained. During the displacement operation described above, each strain gauge G detects the deflection of the deflection beam 11 to detect the actual displacement amount of the fine movement mechanism. Therefore, by performing feedback control based on the detected displacement amount, accurate displacement of the fine movement mechanism can be performed.

[Problem to be solved by the invention]

The above-mentioned fine movement mechanism includes an overhanging portion 2a extending in the Y-axis direction,
It has a structure in which the end portion of the table 6 is fixed to the base, and the table 6 is fixed to the end portions of the overhanging portions 3a and 3b extending in the X-axis direction. Therefore, the overall shape of the fine movement mechanism is a cross shape, and the table 6 itself necessarily has an elongated shape as shown in the figure.

Incidentally, the members to be displaced placed on the table 6 have various sizes and shapes. For this reason, for example, when displacing a member whose length and width are approximately equal to the length of the table 6 in the X-axis direction, the table 6 must also be of sufficient size and shape to place the member to be displaced. It is necessary to use Therefore, in the case of the above example, the shape of the table 6 has to be such that it overhangs in the Y-axis direction from the overhanging parts 3a and 3b, and the proportion of this overhang is thick (in this case, the table 6 itself Due to the weight of the table 6 and the weight of the displaceable member placed thereon, the protruding portion causes a downward deflection.Of course, since the table 6 is made of a rigid body, this deflection is extremely small (for example, several μm), but When performing displacement on the order of sub-μm, this deflection causes a significant decrease in displacement accuracy.

On the other hand, the above deflection can be avoided by increasing the rigidity of the table 6 (for example, by increasing its thickness), but if such a measure is adopted, the weight of the table 6 becomes large and the fine movement mechanism The above means cannot be adopted because the natural frequency is low, the inertia is large, and vibrations occur when the fine movement mechanism is driven at high speed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fine movement mechanism that can solve the problems of the prior art described above and prevent table deflection.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a fine movement mechanism including at least one set of parallel deflection beam displacement mechanisms arranged symmetrically around a central rigid body part and a table on which a member to be displaced is placed. The dimensions of the parallel flexible beam are equal to or larger than those of the member to be displaced, and the length of the parallel flexible beam displacement mechanism on the side to which the table is fixed in the displacement direction is approximately equal to the length of the table in that direction; The displacement mechanism is characterized by comprising four or more parallel flexible beams.

[Effect]

The member to be displaced is placed on the table so as not to protrude outward from the edge of the table, and the table does not protrude significantly from the edge in the displacement direction of the parallel flexible beam displacement mechanism to which it is fixed. Then, when the parallel flexible beam displacement mechanism is driven, the table is displaced in the displacement direction of the driven parallel flexible beam displacement mechanism while remaining in a flat state with no deflection.

〔Example〕

Hereinafter, the present invention will be explained based on illustrated embodiments.

FIG. 1 is a plan view of a fine movement mechanism according to an embodiment of the present invention. In the figure, 21 is a central rigid body part, 22a, 22b are overhanging parts extending in the Y-axis direction, 23a, 23b are overhanging parts extending in the X-axis direction, 24a, 24b are fixed parts, 25a, 25
b is a table connection part. Also, 22 F-922Fx
b is a parallel deflection beam displacement mechanism that is arranged symmetrically with respect to the central rigid body part 21 and generates displacement in the X-axis direction, 23F, □ 2
3Fyb is a parallel deflection beam displacement mechanism that is arranged symmetrically with respect to the central rigid body portion 21 and generates displacement in the Y-axis direction.

The functions of the above-mentioned parts are the same as those of the parts having the same names in the fine movement mechanism shown in FIG. 3, and therefore the operation of the fine movement mechanism of this embodiment is also the same as that of the fine movement mechanism shown in FIG.

The configuration of this embodiment differs from the configuration of the fine movement mechanism shown in FIG. 3 in the parallel deflection beam displacement mechanism 22F, which includes overhangs 22a and 22b to which the table is fixed.

22F-b The dimension in the X-axis direction has been significantly increased without changing the dimension in the OY-axis direction, and accordingly, the parallel flexible beam displacement mechanism 23 Fy, 23 also includes the overhanging portions 23a and 23b. The point is that the dimensions in the Y-axis direction of v and b are significantly increased without changing the dimensions in the X-axis direction.

Due to the above-mentioned increase in dimensions, the dimensions of the connecting parts 253, 25b that connect the tables also increase significantly. Therefore, even if the member to be displaced is large, the table on which it is placed can be moved away from the connecting parts 25a, 25b. It can be constructed without significantly protruding in the X-axis direction, and it is possible to prevent deflection of the table and, by extension, deflection of the member to be displaced.

Since the fine movement mechanism of this embodiment has the above-described configuration, the member to be displaced placed on the table is often large in size. For this reason, the total weight of the table and the member to be displaced is often large, and if only two parallel deflection beams 11 are provided as in the parallel deflection beam displacement mechanism of the conventional fine movement mechanism, these parallel deflection beams 11 cannot be used. There is a possibility that a case may arise where it cannot bear to support the above-mentioned total weight. Therefore, the parallel flexible beam of this embodiment needs to be thicker than the conventional parallel flexible beam 11, but increasing the thickness will reduce the amount of deflection. This will be explained with reference to FIG.

FIG. 2 is a perspective view of a flat flexible beam. This flexible beam is fixed at one end and free at the other end. Now, determine the dimensions of this flexible beam as shown. In the figure, 1: Length of the flexible beam b: Width of the flexible beam h: Thickness of the flexible beam P: Force acting on the flexible beam. Then, the amount of deflection δ of the flexible beam is expressed by the following equation, where E is Young's modulus.

(As is clear from Equation 11, when the thickness h of the flexible beam is increased, the amount of deflection δ is greatly reduced. This is the same for parallel flexible beams.The decrease in the amount of deflection δ is due to the displacement of the parallel flexible beam displacement mechanism. degrade performance.

In this embodiment, in order to eliminate the above-mentioned drawbacks, each parallel deflection beam displacement mechanism is provided with a parallel deflection beam 11° other than the existing parallel deflection beam 11. That is, a new parallel flexible beam 11' is provided between the parallel flexible beam 11 and the piezoelectric actuator 12, which has become larger by increasing the length of each parallel flexible beam displacement mechanism in the displacement direction. The thickness of these parallel flexible beams 11" is t
It is assumed that the thickness is almost the same as that of i. As a result, the weight of the table and the weight of the member to be displaced placed on it are equal to each other of the parallel deflection beam displacement mechanisms 22FX, 22FXb.

23 Fy123 Fyb parallel flexible beam 11.11'
It is possible to support the total weight of the table and the member to be displaced without increasing the thickness of the parallel flexible beams.

In addition, by doubling the number of parallel deflection beams, each parallel deflection beam displacement mechanism 22 F,..., 22 FXb+2
The force required to drive 3F, □ 23Fyb also increases, but this can be solved by increasing the driving force of each piezoelectric actuator 12. In this case, although the dimensions of each piezoelectric actuator 12 increase, no problem arises because the dimensions of each parallel deflection beam displacement mechanism in the displacement direction also increase.

In this way, in this example, the dimension of the parallel deflection beam displacement mechanism in the displacement direction is increased to be approximately equal to the dimension of the table, so a large table is used to place a large member to be displaced. Even if the table is bent, the table will not be bent, and a large member to be displaced can be displaced with high precision. In addition, since there is no need to increase the thickness of the table to prevent table deflection, the weight of the table can be reduced, thereby preventing a drop in the natural frequency of the fine movement mechanism and allowing it to be driven at high speed. Can be done. Furthermore, since the number of parallel flexure beams in the parallel flexure beam displacement mechanism has been doubled, the weight of the table and the members to be displaced can be supported without hindering the function of the parallel flexure beam displacement mechanism. can.

In the description of the above embodiment, a two-axis fine movement mechanism of the X and Y axes was exemplified, but it is obvious that the present invention is also applicable to a single-axis fine movement mechanism.

Further, although an example in which four parallel flexible beams are provided in the parallel flexible beam displacement mechanism has been described, the number of parallel flexible beams may be four or more depending on the weight of the member to be displaced or the table.

〔Effect of the invention〕

As described above, in the present invention, the dimension in the displacement direction of the parallel deflection beam displacement mechanism is made almost equal to the dimension of the table, which is larger than the dimension of the member to be displaced, so that deflection of the table is prevented and highly accurate displacement is performed. be able to. Furthermore, since there is no need to increase the thickness of the table, it is possible to suppress an increase in the weight of the table and enable high-speed drive of the fine movement mechanism.

Furthermore, since the number of parallel flexure beams in the parallel flexure beam displacement mechanism G with increased dimensions has been increased to four or more,
The weight of the table and the displacement mechanism can be supported without causing a hindrance to the function of the parallel beam displacement mechanism.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a fine movement mechanism according to an embodiment of the present invention, and FIG.
The figure is a perspective view of a flexible beam, and FIG. 3 is a perspective view of a conventional fine movement mechanism. 11.11°----parallel flexible beam, 12...-
---One piezoelectric actuator, 21...-Okishin rigid body part, 22 F, . 22 FXb, 23 Fya, 23 Fyb--...
-Parallel deflection beam displacement mechanism, 25a, 25b-・-・-・
Table connection part. Figure 1

Claims (1)

[Claims] In a fine movement mechanism comprising at least one set of parallel deflection beam displacement mechanisms arranged symmetrically around a central rigid body portion and a table on which a member to be displaced is placed, the dimensions of the table are greater than or equal to the dimensions of the member to be displaced; The length of the parallel flexible beam displacement mechanism on the side to which the table is fixed in the displacement direction is approximately equal to the length of the table in that direction, and the parallel flexible beam displacement mechanism is composed of four or more parallel flexible beams. A fine movement mechanism characterized by the following structure.