JP2527012B2 - Micro movement stage - Google Patents

Description

The present invention relates to a minute moving stage device used as a final stage minute amount positioning device on the order of nm in a semiconductor manufacturing apparatus, a microscope, or the like.

[Prior art and its problems]

There is an actuator that uses a laminated piezoelectric element as an actuator for moving the stage in a minute movement stage device used for a minute amount positioning device of the nm order such as a conventional semiconductor manufacturing device or a microscope. There was a defect that it deformed when a force was applied in the direction perpendicular to.

In order to reduce it, as shown in FIG.
Although there is an example of using as a coupling, there is no change in the point of receiving so-called interference, that is, the parallel spring 18 is slightly displaced in the X direction when it is moved in the Y direction.

A method of applying a non-contact force using electromagnetic force like a magnetic levitation device is also conceivable, but it has the drawback of causing thermal deformation and thermal strain due to heat generation because a large current is passed.
The electromagnet is large and the device cannot be downsized.

Further, Japanese Patent Application Laid-Open No. 60-180481 discloses a device in which a bimetal is brought into contact with a rod to perform a masticatory movement, but sliding wear powder of the bimetal may occur.

[Problems to be Solved by the Invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a highly precise, compact and lightweight micro-small-amount moving stage device which is free from the influence of interference and thermal strain due to an actuator unlike the above-mentioned conventional device.

[Means for solving the problem]

The present invention has been made to solve the above problems, and a stage in which electrodes such as metal foil are provided on each side of a polygon made of an insulating material such as ceramic, and a slightly similar shape to this polygon stage. A base having a large hole, and a conductive metal foil such as an Al foil having an insulating ferroelectric film coated on the counter electrode provided on the side of the base hole facing the electrode of the stage and an insulating ferroelectric material are laminated. The movable stage device is composed of the electrode and the elastic spring that generates a force that opposes the electrostatic attraction force of the electrode and the electrode, and the stage is positioned by controlling the voltage applied to the electric electrode. It is a thing.

[Action]

The stage is positioned by balancing the electrostatic attraction force generated by the control voltage applied to the electrodes and the repulsive force of the elastic spring.

〔Example〕

FIG. 1 is a schematic view of an embodiment of the present invention seen from above, FIG. 2 is an enlarged view of an electrode portion thereof, and FIG. 3 is a transverse sectional view.

In the figure, reference numeral 1 denotes a quadrilateral stage made of an insulating material having a small thermal expansion such as ceramics, which has four corners suspended by elastic springs 2 and a bottom surface supported by a flat bearing 13 such as a flat ball bearing or a static pressure flat bearing.

The stage 1 is moved by providing conductive metal foils such as Al foils provided on four sides and electrodes 3 to 6 similar to capacitor electrodes in which ferroelectrics such as polycarbonate are laminated, and facing the squares. Electrodes 7 to 10 made of a conductive metal foil such as Al foil are provided on each side of the hole, and the electrostatic attraction force is generated by the potential difference between the electrodes.

The electrodes 3 to 6 are provided on the four sides of the inner surface of the base 11 having a square hole, and the base 11 is provided with a seat for fixing the flat ball bearing 13 at the center thereof and is fixed to the ground via the bed 14. .

Now, as shown in FIG.
K, the inter-electrode (e.g., the electrodes 4 and 8) the distance X _0, where the movement amount from the When X force of the spring _{F B = K · X ...... (} 1) when the suction force F = 0 static Electric attraction force F _C = C ₀ · V ² / (X ₀ −X) ² (2) C ₀ : constant V: potential difference. Therefore, in order to stop at X where the forces of both are balanced, the potential difference V is May be applied to the electrode 4.

Here, when the electrostatic attraction force F _C and the rigidity K _C are calculated by the following equations, they are as follows.

Where ε ₀ is the permittivity of air, W is the lateral width of the electrode, L is the vertical width of the electrode, and δ is the gap width. If you put Is represented. Therefore, the rigidity Kc is As an example of trial calculation, if the above values of ε ₀ · W, L, δ are the following values ε ₀ = 8.85 × 10 ^-12 F / m W = 30mm L = 15mm δ = 10μm and the applied voltage is 300V and 3000V, suction The force F _C and stiffness K _C are shown in the table below.

Therefore, it can be seen that the suction force and the rigidity that require a slight displacement can be obtained.

In this example, for example, it is determined whether to move in the positive direction or the negative direction in the X direction, and between the + electrode 6 and the electrode 10 or the electrode 4
If a voltage is applied between the electrode and the electrode 8, it can move to either side. The same applies to the Y direction.

Around the electrodes, PZT [P _b (Z _r , T _i ) 0 ₃ ] on the surface of electrodes 3 to 6 to avoid electrode damage due to contact between the electrodes.
Is coated with an insulative strong attractant film 12.
Needless to say, a stable movement amount can be maintained by measuring the movement amount X with a sensor and applying a control voltage to each electrode.

FIG. 4 shows another embodiment, in which a bottom portion of the stage 1 is provided with a recess 15 having a shape similar to the outer periphery of the stage, and a recess 15 is provided with a columnar post 16 having a shape similar to the recess 15 at the center of the pad 14. The spring 2 is arranged between the inner side of the recess 15 and the outer side of the post 16 so that the elastic spring 2 is not provided in the space between the stage 1 and the base 11 as in the above-described embodiment.

FIG. 5 shows another embodiment, where stage 1 and base
The shape of 11 is triangular and the number of electrodes is reduced.

FIG. 6 shows still another embodiment in which electrodes 4-8, 4'are arranged in parallel to either X or Y axis (Y axis in the example) so that the stage can be moved also in the rotational direction. -8 ', 6-10,
6'-10 is arranged. Rotation is obtained by applying a voltage to 4-8 and 6'-10 '.

〔The invention's effect〕

As described above, in the present invention, the force is applied in a non-contact manner,
It is not affected by other axes.

Further, since the actuator is an actuator that obtains a displacement due to an electrostatic attraction force by applying an electric field, it does not have a bad influence due to thermal strain on the mechanism portion due to heat generation unlike an electromagnet, and thus high accuracy can be achieved. Further, since it is sufficient to dispose the electrodes, there is an effect that the mechanism can be made compact and lightweight.

[Brief description of drawings]

FIG. 1 is a schematic view of an embodiment of the present invention viewed from the top, FIG.
The figure shows an enlarged side view of the electrode part.
FIG. 4 is a cross-sectional view showing another embodiment, FIG. 5 is a plan view showing the construction of another embodiment, FIG. 6 is a schematic view of the other embodiment seen from above, and FIG. It is an expanded sectional view of an example. 1 ...... Stage 2 ...... Elastic spring 3 to 6 ...... Fixed side electrode 4 ', 6' ...... Fixed side electrode 7 to 10 ...... Movable side electrode 10 ', 12' ...... Movable side electrode 11 ...... Base 12 Insulating ferroelectrics 13 Flat bearing 14 Head 15 Recess 16 Post 17 Piezoelectric element 18 Parallel spring 19 Ball

Claims (3)

(57) [Claims] 1. A stage in which an electrode is provided at a central portion of each side of a polygon made of an insulating material, a plane bearing for supporting the stage in a plane, and a similar shape slightly larger than the polygonal stage in which the stage is housed. A hole is provided, and each side facing the electrode is provided with a base provided with an electrode in which a metal foil and a strong insulating dielectric material are laminated, and an elastic spring facing the electrostatic attraction force of the electrode and the electrode, Micro-small-amount moving stage device characterized by controlling voltage applied to electrodes 2. A fine moving stage apparatus according to claim 1, wherein an elastic spring is arranged in a space formed by the stage and the base. 3. A fine moving stage apparatus according to claim 1, wherein a recess is provided at the bottom of the center of the stage, a post of similar shape is provided in the recess, and an elastic spring is arranged between the recess and the post.