JPS6044838B2 - Rotary fine movement mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a J-rotation fine movement mechanism that rotates an object position with high precision.

[Technical background of the invention and its problems]

In recent years, electron beam writing equipment, reduction projection type transcription equipment, and X-ray transcription equipment have been developed to form fine patterns on samples such as semiconductor wafers and mask substrates. In order to maintain accuracy on the micron level, a drive mechanism that drives minutely is required.

Further, a fine movement drive mechanism with high precision is required not only in the above-mentioned apparatus but also in fields where precise measurements are performed using measuring instruments. Fine movement drive mechanisms include those that move in a uniaxial direction and those that perform rotational movement, but conventional rotary fine movement mechanisms that perform rotational movement have had the following problems. In other words, it is difficult to perform fine movement when the stroke is long, and it is difficult to make a long stroke when the movement is possible. For example, the rotation mechanism described in a known document (Operating Characteristics of Electric Positioning Mechanism, 1976 Preliminary Machinery Society of Japan Autumn Conference Preprint, p. 359) distorts a material with a piezoelectric effect to convert it into rotational motion. However, in this case, only an extremely short stroke of ±2 [μm] can be taken at a radius of 29 [μm].

In addition, as a device that utilizes the piezoelectric effect,
Publication No. 497 has a one-step fine movement device, but what is described here is a linear movement type step drive.
In order to convert this into rotational motion, a rotary table using conventional bearings must be used, and in order to eliminate play, a rotation mechanism such as a cantilever beam that utilizes the elastic deformation of the material is required. must be used. In this case, the former causes problems such as the generation of play within the bearing and the inability to increase the rotational stroke, while the latter cannot solve the problem of the rotational stroke as before. In order to solve the above-mentioned problems, the present inventors have recently developed a rotational micro-tremor as shown in FIGS. 1A and 1B. He devised a mechanism (Japanese Patent Application No. 19328/1983).

This method allows a large rotational stroke, and in principle can be driven for more than one rotation, and can be driven in minute steps of 0.
Fine movement of about 0.005 [μm] is possible. The rotational fine movement drive mechanism will be explained below. Figure 1! 1a is a plan view, and FIG. 1b is a cross-sectional view taken along arrow A-A in FIG. 1a.
In the figure, 1 is a rotating plate, and this rotating plate 1 is a semi-disc-shaped first plate.
and second moving members 2 and 3 are connected by an elastic hinge 4. In reality, the above-mentioned results can be achieved by partially cutting out two parts of the outer periphery of the disc, which are symmetrical about the central axis of the disc, and by providing notches from the notches toward the central axis. A rotary plate 1 consisting of moving members 2, 3 and an elastic hinge 4 is formed. The rotary plate 1 is movably placed on a conductive base 5, and
The center of rotation is defined by a pin 6 provided on the lower surface of the elastic hinge 4, which is the center thereof. First and second drive members 7 and 8 are provided in the cutout portion of the rotating plate 1, respectively.

These driving members 7 and 8 are each made of a piezoelectric element that expands and contracts according to the applied voltage, and the first and second moving members 2 and 3 are located at both ends in the direction of expansion and contraction (in the direction of the arrow shown in the figure). are each attached and fixed. Note that this fixing may be done by adhesion, screwing, press-fitting, or the like. Further, a variable voltage power source 10a is connected to the first driving member 7 through a switch 9a, and a variable voltage power source 10b is connected to the second driving member 8 through a switch 9b. On the other hand, a first electrostatic chuck (fixed member) 11 consisting of an electrode 11a and insulators 11b and 11c is provided at the lower part of the first moving member 2,
By connecting a power source 14a between the electrode 11a and the base 5 via a switch 13a, the first moving member 2 is suctioned and fixed onto the base 5. Further, a second electrostatic chuck 12 similar to the electrostatic chuck 11 described above is provided at the bottom of the second moving member 3, and the second moving member 3 is attracted to the base 5 by this chuck 12. It has become fixed. In the rotational fine movement mechanism constructed in this manner, the second moving member 3 is first attracted and fixed onto the base 5 by the second electrostatic chuck 12 .

In this state, the first drive member 7 is extended, and the second
The drive member 8 of is retracted. As a result, the first moving member 2 rotates slightly in the direction of arrow P around the elastic hinge 4 due to the strain of the elastic hinge 4, as shown in FIG. 2a.
Next, the first moving member 2 is fixed on the base 5 by the first electrostatic chuck 11, and then the second electrostatic chuck 1
The fixation of the second moving member 3 by 2 is released. When the first driving member 7 is contracted and the second driving member 8 is expanded in this state, the second moving member 3 moves in the direction of arrow P centering on the elastic hinge 4, as shown in FIG. 2b. Rotate slightly. By repeating the above operations, the rotary plate 1 consisting of the first and second moving members 2 and 3 is rotated in the direction of arrow P about the pin 6 due to the strain of the elastic hinge 4. In this way, the rotary plate 1 can be driven slightly and the rotation stroke can be lengthened by this repeated operation.

Further, by adjusting the voltages applied to the drive members 7 and 8, coarse movement and ultra-fine movement of the rotary plate 1 can be easily performed. By the way, in such a mechanism, the center of rotation generates almost no torque, so in order to extract the rotational motion to the outside, the top view is shown in Fig. 3a, and the
As shown in FIG. 2A (7) B-B direction arrow view in FIG.
This rotary table 15 must be rotated.

In addition, in the figure, 16a to 16d each indicate a roller bearing. Therefore, the rotation of the rotary table 15 is intermittent. For example, if a rotation shaft is attached to the moving member 3, the rotary table 15 will stop while the other moving member 2 is rotating. For this reason, when performing rotational adjustment by step movement, there is a problem in that it is difficult to make adjustments because the rotary table 15 is in a resting state. Further, in order to improve the precision of rotational fine adjustment, the driving members 7 and 8 may be installed at a location where the radius of the rotary plate 1 is large, but in this case, the overall structure becomes larger, which is not preferable. [Object of the Invention] The object of the present invention is to enable fine-movement drive, to make the rotation stroke sufficiently long, to prevent the occurrence of backlash that accompanies the drive, and to perform continuous rotational movement. The purpose of the present invention is to provide a rotational fine movement mechanism that can perform rotational fine movement.

[Required of the Invention] The gist of the present invention is to apply an appropriate electric field to a member having a piezoelectric effect (a function of expanding and contracting in accordance with applied voltage), causing the member to expand and contract, thereby causing micro-movement. In the mechanism shown in FIGS. 1A and 1B, an elastic structure is provided on the moving member, and rotational force is extracted through the elastic structure.

In the structure shown in FIGS. 1A and 1B, there are two rotating plates.
Because it is divided, rotation has become intermittent.

By connecting the moving members with the elastic structure, the elastic structure on the side where the drive member is extended also stretches, and the elastic structure on the side where the drive member has contracted also contracts. Therefore, if any of the moving members moves, this elastic structure will necessarily move. By doing this, rotation is continuously transmitted to the elastic structure. By transmitting this rotation to the outside via the elastic structure, the rotation is transmitted continuously instead of intermittently as described above. Moreover, since the rotation angle is reduced by the elastic structure, a mechanism with better rotation accuracy than the mechanisms shown in FIGS. 1A and 1B can be obtained. The present invention has focused on such points, and the first and second moving members are movably placed on the base, and the first and second moving members are mounted on both ends of the driving member in the direction of expansion and contraction, which expands and contracts according to the applied voltage. 2 moving members are respectively attached, a fixing member is provided which alternately fixes the first and second moving members on the base and always fixes at least one of these moving members; Second
means for determining the center of rotation of the movable member, for example, an elastic hinge connecting the first and second movable members;
and a rotational fine movement mechanism that rotates the second moving member around a single axis, for example, the elastic hinge,
As a means for transmitting the rotation, each of the moving members is connected at a portion other than the center of rotation by an elastic structure that can be expanded and contracted in the moving direction of the first and second moving members.

〔Effect of the invention〕

According to the present invention, there is no disadvantage that the rotation stroke becomes extremely short when fine movement is performed as in conventional rotation mechanisms, and rotation of one rotation or more is theoretically possible.

Therefore, a rotation mechanism for coarse movement and fine movement becomes unnecessary. Moreover, since the rotating part (first and second moving members) is directly driven by a drive member made of a piezoelectric element as a drive source, ultra-fine movements of, for example, 0.005 [μm] at -1 [] are reliably achieved. can be done. Furthermore, since an elastic hinge or the like is provided at the center of rotation or at a portion where rotational strain occurs, the rotating shaft does not require a normal bearing, so it is possible to prevent play from occurring during driving. Furthermore, the number of members having a piezoelectric effect varies depending on the magnitude of the applied voltage, but the number of
It is possible to generate a force of 0 Ckg] to several [t], and since the rotation is directly driven, it is possible to provide a rotation mechanism that generates a large torque. In this case, it is possible that the portion pressed by the fixing member may slip, but this can be corrected by appropriately adjusting the pressing force of the fixing member depending on the transmitted torque. Further, according to the present invention, the following effects can be obtained compared to those shown in FIGS. 1A and 1B.

That is, if either one of the movable members is moving, rotation can be transmitted, and unlike a movable member that moves intermittently, a rotated body such as a rotary table can be continuously moved. Furthermore, since the rotational force is transmitted through the elastic structure as described above, rotational accuracy can be further improved. Moreover, the elastic structure can absorb the sudden acceleration that occurs when a voltage is applied to the driving member or the fixed member to rotate or fix the movable member. It is possible to prevent adverse effects on samples, etc. Further, since the present invention has an extremely simple configuration and does not use any parts that may break down, it is sufficiently reliable even when used by being incorporated into measuring instruments or various semiconductor manufacturing equipment. Furthermore, in devices that use charged particles such as electron beams and ion beams, the charged particles are affected by fluctuations in the magnetic field, but in the present invention, all constituent materials can be made of non-magnetic materials, and this point can be overcome. Therefore, it is extremely useful for devices that use charged particles. [Embodiment of the Invention] FIG. 4 is a plan view showing a schematic configuration of a rotation fine movement mechanism according to an embodiment of the invention.

In addition, the same parts as in Fig. 1A and b are given the same reference numerals.
A detailed explanation thereof will be omitted. This embodiment is shown in FIG. 1 above.
The difference from the mechanisms shown in A and b is that the first and second moving members 2 and 3 are connected by elastic structures 21 and 22. That is, the movable members 2 and 3 are connected between their centers and the drive members 7 and 8 by the elastic structures 21 and 22 together with the elastic hinge 4! It is. In fact, by cutting out two parts of the outer periphery of the disc that are symmetrical about the central axis of the disc, and also cutting out a desired part of the disc symmetrically, the movable members 2, 3 and the elastic The hinge 4 and elastic structures 21 and 22 are integrally formed. Makuta, electrostatic chuck mechanisms 11, 12, various switches 9a, 9b, 1
3a, 13b and power supplies 10a, 10b, 14a, 14
b are connected in the same way as in FIG. 1A and b. With such a configuration, the second
By extending the first driving member 7 and contracting the second driving member 8 while the second moving member 3 is suctioned and fixed on the base 5 by the electrostatic chuck 12,
The first moving member 2 rotates slightly in the direction of arrow Q around the elastic hinge 4 as shown in FIG. 5a.

Next, the first moving member 2 is moved by the first electrostatic chuck 11.
is suctioned and fixed onto the base 5, and then the fixation of the second moving member 3 by the second electrostatic chuck 12 is released.

When the first driving member 7 is contracted and the second driving member 8 is expanded in this state, the second moving member 3 rotates slightly as shown in FIG. 5b. Here, the elastic structure 21,
Regardless of the intermittent movements of the movable members 2 and 3, both of them extend and contract continuously.

Therefore, by transmitting rotational motion through the elastic structures 21, 22, even if the movable members 2, 3 are rotated by the same rotation angle as in the conventional case, the elastic structures 21, 22 are rotated by approximately half the rotation angle. rotates, allowing highly accurate rotation control. Furthermore, it can be driven using exactly the same drive system as in FIGS. 1A and 1B, the rotation accuracy is doubled, and vibrations caused by rotation are also absorbed by the elastic structures 21 and 22. Thus, according to this embodiment, not only can the rotary plate 1 be moved slightly and its rotation stroke lengthened, but also rotational force can be extracted continuously.

FIG. 6 is a partially cutaway plan view showing the main structure of another embodiment.

Note that the same parts as in FIG. 4 are given the same reference numerals, and detailed explanation thereof will be omitted. This embodiment differs from the previously described embodiments in the shape of the rotating plate 1. That is, two places on the outer periphery symmetrical about the central axis of the disc are cut out, and a cut is made in a desired part of the disc, and as shown in FIG. A rotary plate 1 consisting of bodies 31 and 33 is formed. In addition,
In the figure, 33a, 33b, 34a, 34b are the drive members 7.
, 8 are shown, and 34 is a threaded hole for connecting the rotary table 15. Of course, even with such a configuration, the same effects as in the previous embodiment can be achieved.

Note that the present invention is not limited to the embodiments described above.

For example, when a sample is rotated, such as in semiconductor manufacturing equipment, and the stability of the subsequent stopping position is important, an electrostatic chuck is provided on the elastic structure, and the elastic structure is clamped after alignment adjustment. You may also do so. By doing so, it is also possible to prevent wobbling and the like due to free vibration due to external disturbances. In addition, although the above embodiment shows a structure in which an elastic hinge is provided at the center of rotation, this is for ensuring and stabilizing the center of rotation, and is not particularly necessary, and even if the structure is removed, there is no particular need for it. is not a problem. Further, although the movable members are moved differentially, fine rotational movement can be sufficiently performed even with only one moving member on each side. moreover,
The shape, dimensions, etc. of the elastic structure can be changed as appropriate depending on specifications. Furthermore, as a means for fixing the movable member to the base using the fixing member, an electrostatic chuck is used in the embodiment, but the structure and manufacturing method of the electrostatic chuck are disclosed in Japanese Patent Application Laid-Open No. 145351/1983. Various methods can be considered, as shown in 1. Electrostatic chuck.

In addition to the electrostatic chuck, a vacuum chuck or an electromagnetic chuck may be used, or a mechanical clamping method may be used. Further, various power supplies and control methods for driving the drive member can be considered and manufactured according to the purpose. For example, it is possible to freely control the voltage applied to the driving member by increasing the voltage when very coarse movement is desired, and by applying a low voltage when ultra-fine movement is desired. Furthermore, this rotation mechanism can also be used as a kind of fine rotation motor, and by transmitting this rotation to another mechanism, it is also possible to finely move an object. In short, the present invention
Various modifications can be made without departing from the gist of the invention.

[Brief explanation of the drawing]

Figures 1A and 1B show the schematic configuration of the rotational fine movement mechanism that is the basis of the present invention. Figure 1A is a plan view, and Figure 1B is a plan view of the same figure.
Figures 2A and 2B are schematic diagrams for explaining the action of the above mechanism, and Figures 3A and 3B are schematic diagrams showing a method of extracting rotational force from the above mechanism. Figure a is a plan view, Figure 3b is a (7) BB direction arrow view of the same figure, Figure 4
The figure is a plan view showing a schematic configuration of a rotating fine movement mechanism according to an embodiment of the present invention, FIGS. FIG. 3 is a plan view showing a partial configuration. DESCRIPTION OF SYMBOLS 1... Rotating plate, 2... First moving member, 3... Second moving member, 4... Elastic hinge, 5... Base, 6:... Zen, 7, 8...
... Drive member, 9a, 9b, 13a, 13b...
...Switch, 10a, L0b, 14a, 14b...
...Power supply, 11...First electrostatic chuck (
12...second gate electrostatic chuck (second fixing member), 15...rotary table, 21, 22, 31, 32...・Elastic structure.

Claims (1)

[Scope of Claims] 1. A first and second moving member movably mounted on a base, and a piezoelectric element that expands and contracts according to an applied voltage, and the first and second moving members are arranged at both ends in the direction of expansion and contraction. a driving member to which moving members are respectively attached; a fixing member that alternately fixes the first and second moving members on the base and always fixes at least one of these moving members; means for determining rotation centers of the first and second movable members, the first and second movable members being centered on a single axis by the expansion and contraction action of the driving member and the fixing action of the fixed member. In the rotational fine movement mechanism for rotating the first and second moving members, the means for determining the center of rotation is an elastic structure that is stretchable in the direction of movement of the first and second moving members and connects the moving members at a portion other than the center of rotation. A rotating fine movement mechanism characterized by: 2. As means for determining the center of rotation, the centers of the first and second moving members are connected by an elastic hinge that utilizes the elasticity of the material, and an elastic structure that is expandable and contractible in the direction of movement of each of the moving members is used. 2. The rotational fine movement mechanism according to claim 1, wherein the first and second moving members are connected at a portion other than their center of rotation. 3. The fixed member is formed by attaching a piezoelectric element that is expandable and contractible in a direction perpendicular to the direction of expansion and contraction of the driving member to the first and second moving members or a base, and the moving member and the base are connected to each other. 2. The rotational fine movement mechanism according to claim 1, wherein the movable member is tightly fixed on the base by pressing. 4. Claim 1, wherein the fixed member is formed by forming an electrostatic chuck consisting of an electrode and a dielectric layer on the first and second moving members or the base surface layer. The rotational fine movement mechanism described in section. 5. All of the base and each member are made of non-magnetic material, lead zirconate titanate is used as the piezoelectric element having an expansion and contraction action, and beryllium copper, aluminum or titanium is used as other constituent materials. The rotational fine movement mechanism according to claim 1 or 3, characterized in that: