JPH071452B2 - Fine positioning device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fine positioning apparatus used for a semiconductor manufacturing apparatus, an electron microscope, or any other apparatus requiring adjustment on the order of sub μm.

[Conventional technology]

In recent years, in various technical fields, a device capable of fine displacement adjustment on the order of sub-μm has been demanded. Typical examples are semiconductor manufacturing equipment such as mask aligners used in LSI (large-scale integrated circuit) and VLSI manufacturing processes, and electron beam lithography equipment. In these devices,
Submicron-order fine positioning is required, and as the positioning accuracy improves, the degree of integration increases, and high-performance products can be manufactured. Such fine positioning is necessary not only in the above-mentioned semiconductor device but also in various high-magnification optical devices such as electron microscopes. Will greatly contribute to the development of.

Conventionally, such a fine positioning device is disclosed, for example, in "Mechanical Design" magazine, Vol. 27, No. 1 (January 1983), pages 32 to 32.
Various types as shown on page 36 and Japanese Patent Publication No. 57-50
The type described in Japanese Patent 433 has been proposed. The former fine positioning device is configured such that a fine movement table is connected to a support base by two parallel plate springs, and the fine movement table is pressed and driven by an actuator to displace it in translation. In the latter fine positioning device, a plurality of bimorph-type piezoelectric elements are radially provided between a cylindrical central fixing portion and a ring-shaped stage surrounding the central fixing portion, and by driving the bimorph-type piezoelectric elements. The stage is configured to be rotationally displaced.

Further, Japanese Patent Application Laid-Open No. 61-209846 proposes a parallel flexural beam displacement mechanism for generating a translational displacement and a radial flexural beam displacement mechanism for generating a rotational displacement as a fine positioning device. The parallel flexible beam displacement mechanism connects the central rigid body part and the rigid body parts on both sides with parallel flexible beams, and installs an actuator between the central rigid body part and the rigid body parts on both sides to drive this actuator. By doing so, the rigid body portion in the center is translated and displaced. In addition, the radial flexible beam displacement mechanism connects the central rigid body portion and the rigid body portions on both sides thereof with the flexural beams extending radially, and an actuator is provided between the central rigid body portion and the rigid body portions on both sides. By driving the actuator, the central rigid body portion is rotationally displaced.

[Problems to be Solved by the Invention]

The above-mentioned conventional fine positioning device can obtain translational displacement in one axis direction and rotational displacement about one axis, respectively.
It is not possible to obtain translational displacements and rotational displacements of translational 3 axes and rotational 3 axes, and in order to obtain such displacements, a plurality of the fine positioning devices must be stereoscopically combined in series or in parallel. However, when a plurality of units are combined in this way, the load of one unit affects the displacement of the other unit, and the positioning accuracy decreases.

FIG. 5 is a side view for explaining the principle of the 6-axis fine positioning device combined in parallel. In the figure, reference numeral 1 is a plate-shaped fixing member having high rigidity, and 2 is a fine movement table made of a flat plate member having high rigidity, on which an object to be positioned is placed. Reference numeral 3 is a drive link member for connecting between the fixed member 1 and the fine movement table 2, and is constituted by parallel connection of six drive link members 31 to 36 in this embodiment.

The drive link members 31 to 36 have high rigidity with respect to a force or moment in one defined direction,
It has the specification that it can freely flex for forces or moments in other directions, and has the function of being able to drive in one direction defined above. By providing six such drive link members, a fine positioning device having six degrees of freedom (positions of three orthogonal axial components and rotational components around these axes are possible) can be obtained. However, also in this case, unless the drive link members are properly arranged, mutual interference occurs between the drive link members.

The object of the present invention is to solve the above-mentioned problems in the conventional technology,
It is to provide a 6-axis fine positioning device having high positioning accuracy.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a fixing member, a fine movement table, and six drive link members mounted between the fixing member and the fine movement table. , A fine positioning device that generates translational displacements and rotational displacements with respect to a first axis, a second axis, and a third axis that are orthogonal to each other, in each of the drive link members, high only for a force in a specific direction. A translational drive link member having rigidity and driven in the specific direction by an actuator, and a rotary drive link member having high rigidity only with respect to a moment around a specific axis and driven by the actuator around the specific axis are used. The translational drive link member and the rotary drive link member are arranged to face each other along the first axial direction and the second axial direction, and The translational drive link member and the rotary drive link member are arranged along the third axial direction.

[Operation] When the actuator is driven, the translational drive link member or the rotary drive link member is displaced in that direction, and this displacement is transmitted to the fine movement table. When one translational drive link member or rotary drive link member is displaced, the other translational drive link member or rotary drive link member is bent, so that the displacement of the fine movement table is not hindered, and mutual interference between the drive link members is extremely high. Less.

[Examples] Hereinafter, the present invention will be described based on illustrated examples.

First, the beat link member used in the embodiment of the present invention will be described.

2 (a), (b) and (c) are perspective views of elements used for the drive link member. The element shown in FIG. 2 (a) is a prismatic hinge 3a. The prismatic hinge 3a is a highly rigid prism, it is achieved by making the two cutout portions 3a ₃ of opposing U-shaped. Reference numerals 3a ₁ and 3a ₂ denote rigid portions on both sides of the cutout portion 3a ₃ , and reference numeral 3a ₄ denotes a thin portion formed by the two cutout portions 3a ₃ . A passes through the center of the thinnest portion of the thin portion 3a _4, showing the axis parallel to the wall of the thin portion 3a _4. This prismatic hinge 3
a is fixed on one of the rigid body portions 3a ₁ and 3a ₂ , for example, the rigid body portion 3a ₁ , and when a force component in the direction of arrow B orthogonal to the axis A is applied to the other rigid body portion 3a ₂ , the rotation is about the axis A. It produces a moving flexure. However, it has high rigidity with respect to other force components and all moment components.

The above "deflection" is a very fine range of deflection. Similarly, "deflection" and "rotation" in the following sentences are considered to be extremely fine ranges.

The element shown in FIG. 2 (b) is a cylindrical hinge 3b. The cylindrical hinge 3b is a rigid cylindrical, constructed by making notch 3b ₃ of V-shaped cross section. 3b ₁ and 3b ₂ are rigid portions on both sides of the cutout portion 3b ₂ , and 3b ₄ is a very small diameter portion formed by the cutout portion 3b ₃ . A indicates an axis passing through the centers of the rigid body portions 3b ₁ and 3b ₂ and the minimum diameter portion 3b ₄ . In the cylindrical hinge 3b, one of the rigid portion 3b _1, 3b _2, for example, a rigid portion 3b ₁ is fixed and the other rigid part 3b ₂ added moment component about the axis A, the rigid portion 3b ₂ the axis A Rotate around.
Further, the small diameter portion 3b ₄ pole Adding force component perpendicular to the axis A to the rigid portion 3b ₂ produces a deflection. However, it has high rigidity with respect to other moment components and force components in the axis A direction.

The element shown in FIG. 2 (c) is a leaf spring member 3c. The leaf spring member 3c is a highly rigid prism constructed by making two notches 3c ₃ of opposing concave. 3c ₁ , 3
c ₂ is a rigid body portion on both sides of the cutout portion 3c ₃ , and 3c ₄ is a thin plate portion formed by the cutout portion 3c ₃ . A indicates an axis passing through the centers of the rigid body portions 3c ₁ and 3c ₂ and the thin plate portion 3c ₄ , and B indicates an axis passing through the center of the thin plate portion 3c ₄ and orthogonal to the axis A. This leaf spring member 3c
Is one of the rigid body portions 3c ₁ and 3c ₂ , for example, the rigid body portion 3c ₁ is fixed,
Deflection occurs about the axis B when the other of the rigid portion 3c ₂ added moment around axis B. Further, when a force component in the direction orthogonal to the axes A and B is added, the rigid body portions 3c ₁ and 3c ₂ are relatively displaced in the force component direction. It has high rigidity for other force components and all moment components. This characteristic is the same as that of two prismatic hinges connected in series as shown in FIG.

The three examples of the elements used for the drive link member have been described above. The drive link member is configured by appropriately selecting and using these elements or other elements.
Next, two such drive link members will be described as examples.

3 (a) and 3 (b) are side views of the driving liquid member used in this embodiment. 3 (a, 3b is a cylindrical hinge shown in FIG. 2 (b), 3d is a translational joint, and the translational joint 3d and the cylindrical hinges 3b on both sides thereof are connected about an axis A. Although 3b has only three degrees of freedom as described in the explanation of FIG. 2 (b) when it is one, if two of these are connected in series, the force in the two axial directions orthogonal to the axial direction A is obtained. The component causes lateral displacement, so that it is rigid only with respect to the force component in the direction of the axis A,
A hinge having five degrees of freedom is formed, which is soft with respect to other force components and moment components. The translational drive joint 3d is formed by stacking piezo elements, and expands and contracts in the axis A direction, that is, in the rigid component direction by applying a voltage.

In the figure, the upper cylindrical hinge 3b is connected to the fine movement table 2 shown in FIG. 5, and the lower cylindrical hinge 3b is connected to the fixing member 1.

Now, assuming that the fine movement table 2 is not subject to any other mechanical restraint, when a desired voltage is applied to the translational drive joint 3b of this drive link member, each cylinder is moved as described above. Since the hinge 3b has high rigidity in the axis A direction, the fine movement table 2 is displaced in the axis A direction by an amount proportional to the voltage. On the contrary, when a load acts on the fine movement table 2, this drive link member can be flexed freely by the upper and lower cylindrical hinges 3b with respect to load components other than the force component in the direction of the axis A. The fine movement table 2 is not restricted by the load component.

Next, the drive link member shown in FIG. 3 (b) will be described. In this figure, 3a is a prismatic hinge shown in FIG. 2 (a), and five of them are arranged. The center axis of deflection of each prismatic hinge 3a is, in order from the upper prismatic hinge in the figure, an axis parallel to the paper surface, an axis perpendicular to the paper surface, an axis perpendicular to the paper surface, and an axis parallel to the paper surface, and finally to the left. That of the prism hinge projecting toward one side is an axis parallel to the axis A shown in the figure. That is, the second
Two prismatic hinges shown in FIG. 7A are combined in series in the same direction, and two combinations of these two hinges are combined in series by changing the direction at a right angle. This configuration has a force in the direction of axis A,
It is rigid only in two directions of the moment around the axis A, and has four degrees of freedom that are flexible with respect to other forces and moments.

The translational joint 3e is further connected to this in series. The translational joint 3e includes rigid body portions 3e ₁ and 3e ₂ and these rigid body portions 3e.
It is composed of a plurality of parallel thin-walled portions 3e ₃ that connect e ₁ and 3e ₂ . The translation Jiyointo 3e when force in the axial direction A is applied, can be deflected in the axial direction A by the thin portion 3e ₃ bends. It exhibits high rigidity with respect to other loads. The translational joint 3e and four of the prismatic hinges 3a are connected about the axis A as shown in the figure, and the other one
The two prismatic hinges 3a are connected to the prismatic hinges 3a at the lower end at right angles to the axis A. In connecting the translation joints 3e, the rigid body portion 3e ₁ is connected to one prismatic hinge 3a, and the rigid body portion 3e ₂ is connected to the other prismatic hinge 3a. In the figure, the upper prism hinge 3a is attached to the fine movement table 2 shown in FIG.
The rectangular pillar hinges 3a linked to each other at a right angle below are connected to the fixing member 1 (note that the connection relationship may be reversed).

Now, assuming that the fine movement table 2 is not subjected to any mechanical restraint, the prismatic hinge 3a connected to the drive link member at a right angle by an actuator (not shown).
When flexed, a moment about the axis A is generated in this drive link member. This moment is transmitted to the fine movement table 2 as it is because the other prism hinge 3a and the translational joint 3e have high rigidity with respect to the moment around the axis A, and the fine movement table 2 is rotationally displaced about the axis A. On the contrary, when a load is applied to the fine motion table 2, this drive link member can freely flex with respect to the load components other than the moment component around the axis A by the prismatic hinges 3a and the translation hinges 3e. Do not restrain Table 2.

The configuration of the two drive link members has been described above.
Other than these, various configurations using various elements are conceivable, and are not limited to the above two examples.

As shown in FIG. 5, such six drive link members 31
By appropriately connecting the fine movement table 2 and the fixed member 1 in parallel with each other by selectively driving the hinges or joints of the drive link members 31 to 36, the fine movement table 2 can be moved in any direction by any amount. It is possible to displace only. The condition in this case is only that drive links of the same type of translation or rotation are not arranged on the same axis line, and other than this, they may be connected in any direction.

However, when the driving action axes of the drive links are arranged obliquely to each other as shown in FIG. 5, the driving of one drive link interferes with the driving force of the other drive link, and the translation of these six drive links occurs. Since the fine movement stage 2 is driven as a result of the mutual interference between the rotation and the rotation, the calculation of the control becomes extremely complicated. In addition, the setting of the initial value must be performed accurately, and the change of the initial value of one drive link inevitably causes the change of the initial value of the other drive link. It is difficult to drive the position accurately.

In order to solve this, if the drive links are arranged so that the directions of the drive action lines of the above-mentioned six drive links individually correspond to three translation axes and rotation axes that are orthogonal to each other, the drive links Mutual interference can be minimized.

Here, an example of the present invention will be described.

FIG. 1 is a schematic diagram of the configuration of a fine positioning apparatus according to an embodiment of the present invention. In the figure, 21 is a fixing member having high rigidity, and 22 is a fine movement table having high rigidity. 231-2
Reference numeral 36 denotes a drive link member connected between the fixed member 21 and the fine movement table 22. x, y, z indicate coordinate axes set in this fine positioning device. The drive link members 232 and 235 are arranged along the x axis, the drive link members 233 and 236 are arranged along the y axis, and the drive link member 231 is arranged on the lower surface of the fine motion table 22 along the z axis direction. Are arranged along the z-axis. The drive link members 232, 234, 236 are translational drive links having the structure shown in FIG. 3 (a), and the drive link members 231, 233, 235 are rotary drive links having the structure shown in FIG. 3 (b).

With such a configuration, first, the translational drive links 232, 236, 23
Since 4 is arranged along the x-axis, the y-axis, and the z-axis which are orthogonal to each other, the translational drive of any one of the translational drive links does not affect the other translational drive links. In addition, since translational drive does not generate a moment, the rotary drive link 23
Does not affect 5,233,231. Rotary drive link 235,233
Are arranged so as to match the x-axis, the y-axis, and the z-axis, respectively, and the rotary drive links 231 are arranged along the z-axis direction and generate moments about axes orthogonal to each other, so that they interfere with each other. Moreover, since the translation drive link is soft except for the translation direction, it is not affected by the moment.

With this configuration, in the present embodiment, displacements in one axis direction or around one axis can be obtained by driving one drive link member, that is, one degree of freedom and one drive link member can be driven. It is possible to make a one-to-one correspondence, which facilitates control and reduces the reduction in accuracy due to a mechanical error.

Even if the translational drive link and the rotary drive link are arranged in a relationship other than the above, displacement of six axes can be performed. This will be described with reference to the drawings. FIG. 4 is a diagram in which drive links of the same type are arranged on the lower surface of the fine movement table. In the figure, 231 ', 23
4'is a drive link of the same kind, L is these drive links 231 ',
A line on which 234 'is arranged, for example, the x-axis is shown. Further, the illustration of the drive link of the other shaft is omitted.

If the drive links 231 'and 234' are rotary drive links, when one of the two rotary drive links is rotationally driven, a moment about the z axis acts on the fine movement stage to rotate it. The same applies when the two rotary drive links are both driven to rotate in the same direction. When the two rotational drive links generate rotational moments in opposite directions, z
The moment about the axis is canceled and translation occurs in a direction perpendicular to the line L connecting the two rotary drive links 231 'and 234'. In other words, uniaxial rotation and uniaxial translational displacement can be realized by the two rotary drive links arranged in parallel. In this case, assuming that the line L is the x-axis as the drive link of the other axis, the translational drive link and the rotary drive link are opposed to each other along the x-axis, and the translational drive links are provided along the y-axis and the z-axis, respectively. become.

When the two rotary drive links 231 'and 234' are replaced with two translation drive links, translation (when the two are extended / contracted in the same direction) and rotation about an axis perpendicular to the line L (two extension / contraction) When reversed) and occur. In this case, assuming that the line L is the x-axis as the drive link of the other axis, the translational drive link and the rotary drive link are opposed to each other along the x-axis,
One translational drive link along the y-axis and one along the z-axis
Two rotary drive links will be provided.

〔The invention's effect〕

As described above, in the present invention, the translational drive link member and the rotary drive link member are arranged facing each other along the two axial directions between the fixed member and the fine movement table, and the translational drive link member and the rotary drive link member are arranged. Since the link members are arranged along the other axial directions, 6-axis positioning can be performed with high accuracy.

[Brief description of drawings]

FIG. 1 is a schematic view of the configuration of a fine positioning device according to an embodiment of the present invention, and FIGS. 2 (a), (b), and (c) are perspective views of the elements used in the drive link member shown in FIG. 3 (a) and 3 (b) are side views of the drive link member shown in FIG. 1, FIG. 4 is a view showing another arrangement example of the drive link, and FIG. 5 is a parallel coupling type fine positioning device. It is a side view showing an example of. 1,11,21 …… Fixing member, 2,12,22 …… Fine table, 31〜
36,131-133,231-236,231 ', 234' ... Drive link member.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-60-155394 (JP, A) JP-A 61-159349 (JP, A) JP-A 60-52230 (JP, A) JP-A 62- 88008 (JP, A)

Claims (4)

[Claims] 1. A fixing member, a fine movement table, and six drive link members mounted between the fixing member and the fine movement table, the first shaft, the second shaft, and the third shaft being orthogonal to each other. In a fine positioning device for generating each translational displacement and each rotational displacement about the axis of the above, each drive link member has a high rigidity only against a force in a specific direction, and the translational drive link is driven in the specific direction by an actuator. A member and a rotary drive link member that has high rigidity only with respect to a moment about a specific axis and is driven around the specific axis by an actuator are used, and the members are provided along the first axial direction and the second axial direction. Respectively, the translational drive link member and the rotary drive link member are arranged so as to face each other, and the translational drive link member and the translational drive link member are arranged along the third axial direction. Fine positioning apparatus characterized in that a and the rolling drive link member. 2. The translational drive link member according to claim 1, wherein the translational drive link member has a plurality of cylindrical hinges having high rigidity only against a force in the specific direction, and is interposed between the cylindrical hinges. A fine positioning device comprising an actuator driven in the specific direction. 3. The rotary drive link member according to claim 1, wherein the rotary drive link member has a prismatic hinge having high rigidity with respect to loads other than the moment in the specific direction along one axis. While connecting multiple so that the direction does not match the axis and the specific direction is different,
A translational joint having high rigidity against a load other than the force in the axial direction is coupled to the prismatic hinge along the axis, and the prismatic hinge in which the axial direction is displaced from the axis is the specific direction is the axis. Connect to the end of the connecting member along
Further, a fine positioning device comprising an actuator that bends a prismatic hinge connected to the end portion. 4. A fine positioning device according to any one of claims (1) to (3), wherein the actuator is a laminated piezoelectric element.