JPH06217561A - Small mobile body - Google Patents

Abstract

PURPOSE:To provide a small mobile body which is simple not only in wiring and electrode structures, but also in structure of driving mechanism, can effec tively utilize electrostatic forces and elastic forces and transmits the forces after efficiently converting them into mechanical forces, incorporates a control function, and can realize pitching motions and a latching function. CONSTITUTION:The mobile body is equipped with a driving mechanism constituting a driving section 300 just above the upper surface of a silicon substrate 1 constituting the mobile body. The driving mechanism has a spring supporting body 12 as an elastic supporting member and the body 12 supports a pair of electrodes 111 and 112 in such a state that the electrodes 111 and 112 are faced to each other at a variable interval. The pawl 13 at one end of the electrodes 111 and 112 drives the substrate 1 in the mobile section 100 of the mobile body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called micromachine (hereinafter referred to as a micromachine), which is a minute movable body driven by electrostatic force or magnetic force. More specifically, polycrystalline silicon movable bodies manufactured by subjecting polycrystalline silicon, which is used to form integrated circuits on a silicon wafer, to microfabrication technology, various semiconductor materials, metal materials, plastic materials, etc. The present invention relates to a micromachine having a minute shape, which is manufactured by applying fine processing technology.

[0002]

2. Description of the Related Art Conventionally, as an example of a typical research on a micromachine, there is a rotary microrotor in which a minute rotor and a stator are combined (Katsufusa Shono, "CMOS
LSI Engineering "pp. 273-282 (see Nikkan Kogyo Shimbun)). The structure is shown in FIG. Figure 1
7 (a) is a plan view and FIG. 17 (b) is a vertical side view. Shaft 102 with a cap on substrate 101
Is provided, the rotor electrode 103 is provided around the rotor electrode 103, and the stator electrode 104 is provided on the outer periphery of the rotor electrode 103. The rotor electrode 103 and the stator electrode 104 are provided at the same height on the substrate, and by sequentially applying a voltage between the stator electrodes 104 facing each other with the rotor electrode 103 interposed therebetween, the rotor electrode 103 and the stator electrode 104 can be separated from each other. The rotor electrode 103 is rotated by the electrostatic force generated during the period. Hereinafter, an example of the above-mentioned conventional manufacturing method will be described. Polycrystalline silicon, which is a structural material, is deposited by thermal decomposition (CVD method) of monosilane. Photo-etching technology using resist is used for microfabrication of shafts and rotors. Polycrystalline silicon is processed by Freon oxygen plasma etching. Polycrystalline silicon is thermally oxidized SiO ₂ or CVD SiO ₂
It is produced so that it can be wrapped in. By repeating these steps, a micromachine as a micromachine movable body is assembled. In addition, SiO ₂ which is a sacrificial material
Are removed with an etchant at the end of the fabrication process.

Next, a micromirror will be described as another example of the conventional micromachine (see "Optical").
Micro Shutters and Torsional Micro Mirrors Forelight Modulator Araizu (OPTICAL MICTOSHUTTERS AN
D TORSIONAL MICRONIRORSF
OR LIGHT MODULAR ARRAY
S) ", IEEE MEMS '93, Fort Lau
derdale, Florida, pp. 124-12
7). This is formed by using polycrystalline silicon, and is provided on the silicon substrate in parallel with the torsional oscillator supported by the double-supported beam whose both ends are fixed on the silicon substrate, the torsional oscillator supported by the both-supported beam. The mirror surface attached to the torsion oscillator is rotated by applying a voltage between the electrode and the torsion oscillator.

Still another conventional technique is an electrostatic actuator that displaces in one direction. For example, a guide member such as an elastic support spring is provided in order to guide a movable member having a comb-teeth-shaped movable electrode that meshes with the comb-teeth of a fixed electrode in only one direction to increase the amount of displacement (Japanese Patent Laid-Open No. Hei 10-1999) 5-761
No. 86 patent publication).

[0005]

The greatest feature of the micromachine is that it is formed in the size of the micron level. Therefore, conventionally, a micromachine having a structure as simple as possible has been desired. This is because, unless the micromachine has a simple structure, it is impossible to assemble minute individual parts to form a minute mechanical system. Therefore, even in each step of the wafer process, which is a manufacturing process, the manufacturing process must be advanced so as to obtain an assembled shape (completed shape).

[0006] Another feature of the micromachine is that it can realize a minute movement which has never been achieved. Therefore, a movement suitable for a micromachine has been long awaited. That is, for example, a general-purpose machine on a macroscopic scale is strongly affected by gravity and inertia, so the applied force must be large enough to overcome it, but of course micron-order micromachines are naturally less affected by gravity and inertia. Therefore, it is necessary to work on the practical application of micromachines with a new concept. However, in the conventional micromachine, the general-purpose machine on the macroscopic scale is merely miniaturized. There is a strong demand for the discovery of methods suitable for micromachines, including the structure of the micromachine itself, such as the structure that realizes peculiar movements that take advantage of the minuteness of the micromachine, the force that is applied to operate the micromachine, and the transmission method thereof. It was

However, according to the above-mentioned prior art, as can be seen from the example of the micro-rotor, which is a rudimentary trial of micro-machines, wiring for applying voltage to a large number of stator electrodes arranged around the rotor while switching the voltage, There is a drawback in that the structure of the micromachine is complicated, including not only the electrode structure but also the mechanism for supporting the rotor and the mirror.

Moreover, according to the prior art, the rotational force of the rotor is given by the electrostatic force between the end surfaces of the stator and the rotor, which face each other in the radial direction according to the rotation angle. As a result, the electrostatic force cannot be effectively utilized, and the electrostatic force cannot be efficiently converted into mechanical force or the force cannot be transmitted.

Further, not only the micro-rotor but also the above-mentioned micro-mirror can accurately detect the motion state and the position of the minute rotor and the mirror in order to control the rotation speed, the rotation angle and the position (displacement) of the rotor and the mirror. Therefore, a sophisticated detection means must be provided, and as a result, the entire micromachine becomes complicated and large in size, which has been a major obstacle to putting the micromachine into practical use.

Moreover, each of the above-mentioned prior arts has a basic problem that the pitch movement of each pitch and the necessary latch function cannot be realized in the state where no voltage is applied. It was

The present invention has been made in view of the various problems that the above-mentioned prior art has, and has a simple structure suitable for realizing a micromachine, and efficiently converts electrostatic force into mechanical force. The purpose is to provide a minute movable body that can be converted and transmitted to the outside, has a control function in the micromachine itself, and can also realize a pitch movement and a latch function. The purpose is to change the applied electrostatic attraction force to the forward movement and form a micro movable body that moves reliably on the silicon wafer.

[0012]

In order to achieve the above object, in the micro movable body of the present invention, at least a pair of electrodes and an elastic support member that variably supports the electrode interval between the pair of electrodes by elastic force. Be prepared.

Further, in the minute movable body according to the present invention, an alternating current pulse is applied between the silicon substrate and the polycrystalline silicon plate through the insulating film, and at the rising thereof, the polycrystalline silicon which hangs on the bushing support portion of the polycrystalline silicon plate. It is characterized in that the bushing support part makes a pitch movement by giving a twist to the rod and utilizing the fact that the polycrystalline silicon rod twisted at the fall returns to the original position.

In addition to the twist of the polycrystalline silicon rod, it is preferable to utilize the fact that the polycrystalline silicon plate bends.

[0015]

When a voltage is applied to the pair of electrodes of the minute movable body configured as described above, an electrostatic force acts between the electrodes, the electrode spacing is changed in combination with the elastic force of the elastic support member, and the voltage is applied from the electrodes. After the removal, the elastic force of the elastic member works to restore the electrode spacing to a predetermined value, and this operation has a control function itself, so that the micro movable body can move stably even if these operations are repeated. To work.

The present invention, for example, has a cross-sectional area of 3 microns × 3.
It was made by discovering a new force transmission method from a physical property study on the measurement of the elastic constant of a micron polycrystalline silicon rod. Specifically, a polycrystalline silicon rod (for example, a length of 500 microns) obtained by processing the polycrystalline silicon deposited by the thermal decomposition of monosilane using a microfabrication technique has an elastic constant of 150 GPa, and its value is It is comparable to the value for single crystal silicon. When strain is applied within the elastic limit and then the force is removed, the polycrystalline silicon rod returns to its original shape. The same applies not only to bending but also to twisting.

The present invention also pays attention to the mechanical properties of the polycrystalline silicon, applies an AC pulse between the silicon substrate and the polycrystalline silicon plate through the insulating film, and at the rising edge of the polycrystalline silicon plate. The phenomenon itself that the bushing support part makes a pitch motion by using the fact that the polycrystalline silicon rod twisted at the bushing support part of the above is given a twist and the polycrystalline silicon rod twisted at the fall returns to the original, The purpose is to find and meet the purpose of.

In addition to the above-mentioned twist of the polycrystalline silicon rod, the bending of the polycrystalline silicon plate may be used for the bushing support portion to perform the pitch movement.

[0019]

EXAMPLES Some examples of the present invention will be described below.
A description will be given with reference to the drawings. In the following explanation,
The same elements are designated by the same reference numerals to avoid duplication of description.

First, a first embodiment of the present invention will be described. In FIG. 1, a micromachine as a minute movable body is provided with a movable portion 100 and a driving portion 300, and an uneven surface is formed on the upper surface of a silicon substrate 1 which constitutes the movable portion 100. The drive unit 300 is provided in contact with each other. The drive unit 300 is provided with a spring support 12 as an elastic support member, and the spring support 12 holds a pair of electrodes 111, 112 so that they are opposed to each other and the electrode spacing d is variable. A claw 13 is provided at one end of the electrode 111, and the claw 13 meshes with the unevenness on the upper surface of the silicon substrate 1. The electrode 112 is fixed to the outside by a mounting tool (not shown).

The operating principle of the above embodiment will be described below with reference to FIGS. 2 (a), 2 (b) and 2 (c). Electrodes 111, 1
When a voltage is applied between the electrodes 12 (FIG. 2A), an electrostatic force acts between these electrodes 111 and 112, and the spring support 12 is elastically deformed, so that the electrode 111 moves to the electrode 1.
The electrode distance d is narrowed compared to the case where the voltage is applied to the 12 side and no voltage is applied (FIG. 2B). Then, when the voltage is removed from between the electrodes 111 and 112, the elastic restoring force of the spring support 12 causes the electrode 111 to separate from the electrode 112, and the electrode interval d is widened to return to the original state (FIG. 2).
(C)). At this time, the claw 13 at one end of the electrode 111 pushes the concave groove of the silicon substrate 1 in the direction of the arrow in the figure, and moves the movable portion 100 formed of the silicon substrate 1 relative to the driving portion 300. Then, the electrodes 111 and 112
The movable portion 100 is stepped (pitching) by turning on and off the voltage applied in between and repeating the above operation.

According to the above-mentioned embodiment, the amount of displacement corresponding to one pitch of the concaves and convexes engraved on the silicon substrate 1 is secured by applying the voltage once, and the displacement force is the elasticity of the spring support 12. It corresponds to a restoring force, and its displacement position is maintained even when the voltage is turned off. That is, the micromachine having the above-described structure has a control function in itself, and efficiently obtains mechanical motive force by combining electrostatic force and elastic force.

In the above description of the embodiment, the drive part is fixed to the outside and the movable part is stepped for easy understanding, but the movable part may be fixed and the drive part may be moved. Of course, the drive unit can be pitch-moved on the silicon substrate. Further, in the above description, the silicon substrate is taken as an example, but the material and the shape are not limited thereto, and other materials such as plastic and other shapes such as a cylinder can be replaced.

Next, a modified example of the first embodiment of the present invention will be described below with reference to FIG. The structure of this modification is different from the structure of the embodiment shown in FIG. 1 in the following points. That is, one electrode 111 of the driving unit 300 is formed by vapor deposition on one surface of a polyimide elastic plate 121 as an elastic supporting member, and the other electrode 112 is formed on a rigid polyimide fixing plate fixed to the outside. , Electrode 1
The surface of 12 is covered with an insulating layer 2. One end (upper part in the drawing) of the pair of electrodes 111 and 112 is fixed to each other, and the other end (lower part in the drawing) is widened to the bottom.

Hereinafter, FIG. 3 (a), (b), (c),
The operation principle of the above embodiment will be described with reference to FIG. When a voltage is applied between the electrodes 111 and 112 (FIG. 3A),
An electrostatic force acts between the electrodes 111 and 112, and the electrode gap is narrowed at first by deforming the elastic plate 121 from the upper part in the drawing where the electrode gap is narrow, and the electrode gap d is narrowed (Fig. 3 (b)). After that, when the voltage is continuously applied, the electrode 111 reaches the lower part in the figure and is attracted to the electrode 112 side and gradually sticks to the insulating film 2 (FIG. 3).
(C)). The insulating film 2 has a function of maintaining insulation without short-circuiting the voltage between both electrodes even if the electrodes 111 and 112 are attracted by electrostatic force. Then these electrodes 11
When the voltage is removed from between 1 and 112, the electrode 111 is separated from the electrode 112 by the elastic restoring force of the elastic plate 121, and the electrode interval d is widened and returns to the original state (FIG. 3D). At this time, the claw 13 at one end of the electrode 111 is attached to the silicon substrate 1
The concave portion is pushed away to move the movable portion formed of the silicon substrate 1 relative to the drive mechanism 300. Then, the voltage applied between the electrodes 111 and 112 is turned on / off and the above operation is repeated to pitch drive the silicon substrate 2.

According to the above modification, since the pair of electrodes can be formed so as to widen the skirt, the electrode interval in the skirt portion can be widened, and as a result, the pitch motion can be realized at a large pitch. Moreover, the degree of attraction between the electrodes can be adjusted by adjusting the voltage applied between the electrodes. According to this, by adjusting the amount of applied voltage between the electrodes, it is possible to obtain a desired amount of displacement corresponding to an arbitrary number of pitches of irregularities engraved on the silicon substrate 1, and to freely perform pitch movement. Can be controlled.

In the description of the drawings of the above modification, the electrode 111 is provided with the claw 13 and the electrode 11 is provided for easy understanding.
Although 2 is fixed to the outside, the electrode 112 can be fixed to the outside by providing the electrode 112 with a claw. Also,
Although the insulating film 2 is provided on the surface of the electrode 112, it goes without saying that the insulating film 2 may be provided on the surface of the electrode 111 instead of the electrode 112.

Next, the second embodiment of the present invention will be described with reference to FIG.
It is described below with reference to FIGS. FIG. 4 is a perspective view showing a structure of a movable part 500 integrally formed of polycrystalline silicon. The movable part 500 is movably placed on a silicon substrate 1 as a fixed part 600 as shown in FIG. Get burned. The movable part 500 has a cross-section formed in a substantially inverted L shape, and the electrode 111 is formed on a part of the horizontal surface of the movable part 500. A bushing 50 is provided at the other end of the movable portion 500 that extends at a right angle from the extension surface of the electrode 111. An upper side of the bushing 50 is a bushing support portion 51, and beams 17 as elastic support members are provided so as to project to the left and right of the bushing support portion 51. The protruding end of the beam 17 is fixed to the outside (moving element) via a frame body (not shown). At first, in the movable body 500, the electrode 111 is positioned parallel to the other electrode (not shown) formed on the silicon substrate 1, and the foot 52 of the bushing 50 and the surface of the silicon substrate 1 are mechanical. Is supported by the beam 17 so as to be in contact with. The surface of the silicon substrate 1 is covered with an insulating film, and even if the legs 52 of the bushing 50 contact the silicon substrate 1, the movable portion 500 and the fixed portion 600 are electrically insulated.

The operation of the second embodiment will be described below with reference to FIGS. 5 (a), 5 (b) and 5 (c). When a voltage is applied between the electrode 111 of the movable part 500 and the electrode of the silicon substrate 1 of the fixed part 600 (FIG. 5A), an electrostatic force acts between these electrodes, and the beam 17 is twisted to cause the electrodes to move. 111 is attracted to the silicon substrate 1 side, and the movable portion 5
00 is inclined, and the electrode interval d is narrower than before the voltage is applied. At this time, since the movable portion 500 is fixed via the beam 17, the foot 52 is displaced from the position before the voltage is applied by ΔX on the silicon substrate 1 (FIG. 5B).
Next, when the voltage is removed from between the electrode 111 and the electrode of the silicon substrate 1, the elastic restoring force of the twisted beam 17 causes the electrode 111 to separate from the silicon substrate 1 and return to the parallel direction, so that the electrode distance d increases. The posture of the movable part 500 returns to its original position (FIG. 5 (c)). At this time, the movable part 500 moves the foot 5
Since the posture is returned with 2 as the fulcrum, the movable portion 500 moves relative to the fixed portion 600 by ΔX. By turning on and off the voltage applied between the electrodes, the movable portion and the fixed portion relatively perform a pitch motion.

Next, FIGS. 6A, 6B, 6C and 6D.
A modified example of the second embodiment will be described with reference to FIG. 6 (a), (b), (c), and (d),
The electrode 112 on the silicon substrate 1 side of the fixed portion and the insulating film 2 are shown. The configuration of this modified example is different from the configuration of the embodiment shown in FIGS. 4 to 5 as follows. That is, FIG.
In FIG. 6A, the beam 17 is fixed to the movable frame body 16, and in FIG. 6B, the beam 17 is provided near the electrode 111.
In (c), the frame 16 is fixed to the outside, and
This is that the insulating film 2 is provided only on a part of the silicon substrate 1 so that the silicon substrate 1 side as the fixing portion 600 can be moved.

The operation principle of the above modification will be described below.
In the configuration of FIG. 6A, when a voltage is applied between the electrodes 111 and 112, an electrostatic force acts between the electrodes 111 and 112, and the beam 17 is twisted and elastically deformed, so that the electrode 111 is placed on the electrode 112 side. The electrode spacing d becomes narrower than that when no voltage is applied. At this time, FIG.
In (a), the beam 17 is twisted and at the same time the frame 1
6 moves in the direction of arrow 161. Then, when the voltage is turned off, the electrode 111 is separated from the electrode 112 by the elastic force of elastically restoring the twisted beam 17, the electrode interval d is expanded and returned to the original state, and the frame body 16 moves in the direction of the arrow 162. That is, in this modified example, the frame 16 can be vibrated in the left-right direction on the paper surface by repeating turning on and off of the voltage. Next, in the configuration of FIG. 6B, the beam 17 is twisted, and at the same time, the frame body 16 moves in the direction of arrow 163. Then, when the voltage is turned off, the frame body 16 returns in the direction of the arrow 164 due to the elastic restoring force of the twisted beam 17,
The frame 16 can be vibrated in the vertical direction of the paper in the same manner as described above. Further, in FIG. 6C, the frame 1
6 is desired to be fixed, the insulating film 2 and the electrode 112 connected to the insulating film 2 are driven in the direction of arrow 1121 by the bushing 50, and when the voltage is removed from between the electrodes 111 and 112, the beam 17 twisted. Since the electrode 112 moves in the direction of the arrow 1122 by elastically restoring, the silicon substrate 1 can be vibrated in the left-right direction of the paper surface in the same manner as described above.

According to the above modification, the beam 17 has a function of torsional elasticity as an elastic support member, and the movable portion 500 and the frame 1 are provided.
Since it also has a function of mechanically coupling 6, the structure of the minute movable body can be simplified, and the displacement amount of the electrode interval can be converted into vibration without a special transmission mechanism, or transmitted to the outside. It can be taken out without loss. That is, in the micromachine having the above configuration, the displacement amount efficiently obtained by the combination of the electrostatic force and the elastic force can be used as the driving force.

In the above description, the silicon substrate 1 or the frame body 16 vibrates due to the reciprocating movement of the bushing 50, but the silicon substrate 1 or the frame body 16 advances by incorporating the movement described in FIG. You can also make a pitch movement). In this case, it is also preferable to provide a guide rail for guiding along the silicon substrate 1 or the frame 16. In the description of the modified example in FIG. 6C, the electrode 112 is moved for easy understanding, but the electrode 112 and the insulating film 2 on the upper surface thereof are separated,
It is also possible to make only the insulating film 2 movable.

Next, a third embodiment of the present invention will be described with reference to FIGS. The main difference of the structure of this embodiment from the structure of the second embodiment is the movable part 50.
0 is not provided with a special beam or the like, and is simply placed on the fixed portion 600, and at least a part of the movable portion 600 is formed of an elastic member. In addition, this embodiment is characterized in that the movable part 500 can be freely moved on the fixed part 600. The movable part 500 is the electrode 1
The electrode 1 is made of polycrystalline silicon including 11
11 itself also has a function as an elastic support member capable of elastic deformation.

The operating principle of the above embodiment will be described below with reference to FIGS. 8 (a), 8 (b) and 8 (c). Electrodes 111, 1
When a voltage is applied between 12 (FIG. 8A), electrostatic force acts between these electrodes 111 and 112, and the electrode 111 of the movable portion 500 is attracted to the fixed portion 600 by electrostatic force. At this time, the electrode 111 is deformed by utilizing its own elasticity and is attracted to the electrode 112 side. And the movable part 50
Bushing feet 52 extending from 0 and contacting the fixed portion 600
Is displaced in the direction of the arrow shown in the drawing from the position before the voltage was applied (FIG. 8B). Then these electrodes 11
When the voltage is removed from between 1 and 112, the electrode 111 made of polycrystalline silicon slides on the insulating film 2 and is separated from the electrode 112 by its elastic restoring force, and the electrode distance d is widened and returns to the original state. At this time, since the bushing foot 52 of the movable portion 500 serves as a fulcrum and the movable portion 500 moves around the foot 52, the movable portion 500 moves relative to the fixed portion 600 by ΔX (FIG. 8C). ). As described above, the voltage applied between the electrodes 111 and 112 is repeatedly turned on and off to continue the above operation, so that the movable portion 500 moves on the fixed portion 600 with a pitch.

Next, FIGS. 9 (a), 9 (b), 9 (c),
A modified example and operation of the above embodiment will be described with reference to (d) and (e). In the modified examples shown in FIGS. 9A, 9 </ b> B, and 9 </ b> C, the apex of the angle α sandwiched between the electrode 111 and the bushing 50 has elasticity. Further, in the modified example shown in FIG. 9D, the electrode 111 and the bushing 50 themselves also have elasticity. Further, in the modified example shown in FIG. 9E, the apex of the angle α has elasticity and the electrode 111 has the fixing portion 60.
0 is maintained parallel to the top surface. Then, according to the modified example, when a voltage is applied, the angle α is changed according to the elasticity of the apex and the electrode 111 is attracted to the fixed part 600 side (FIGS. 9A, 9B, and 9C). ). Alternatively, the electrode 11
1 and the bushing 50 have elasticity, the electrode 111 and the bushing 50 are elastically deformed so that the movable part 500 is fixed.
Is sucked in (FIG. 9 (d)). Alternatively, the movable portion 500 may be maintained while the electrode 111 remains parallel to the fixed portion 600.
Is deformed (FIG. 9 (e)). Thereafter, when the voltage is removed from these electrodes, the elastic restoring force of the movable portion 500 causes the electrode 111 to separate from the fixed portion 600 and return to the original state. The various modified examples described above can be applied to, for example, a mirror for a display plate or an optical deflector such as an optical integrated circuit.

Next, another modification of the third embodiment of the present invention will be described below with reference to FIG.
The configuration of this modified example is different from the configuration of the modified example as follows. That is, the movable part 500 includes
The movable part 500 described in the above is used. And
On the upper surface of the fixed part 600, a power supply electrode 11 for supplying a voltage to the electrode of the movable part 500 via the insulating film 2 on the electrode 112 of the fixed part 600 facing the electrode of the movable part 500.
3 are provided in a grid pattern on the XY plane, and the movable part 500
The electrode and the electrode 113 of the fixed portion 600 are electrically connected by mechanical contact.

The operation principle of the above modification will be described below. When the electrodes 113 arranged in an XY matrix are selected corresponding to the addresses on the XY plane where the movable portion 500 is located and a voltage is applied between the electrodes 113 and 112, the electrodes 113
Since the electrode 111 and the electrode 111 are electrically connected, the movable part 50
An electrostatic force acts between the electrode 111 of 0 and the electrode 112 of the fixed portion 600, and when the voltage applied between the electrode 113 and the electrode 112 is removed, the electrode 111 of the movable portion 500 separates from the electrode 112 ( The operation is the same as the operation of the various embodiments described above.) According to the principle described above, the movable section 500 causes the X-axis according to the address (address) selection of the electrode 113.
Move freely on the Y plane.

According to the above-described modification, since it is possible to energize the movable portion 500 without directly wiring it, it is possible to construct a micromachine that freely moves on the XY plane. Moreover, since it is driven by electrostatic force, the movable portion 500 does not have to be separated from the fixed portion 600.

In the above description of the modified example, the movable portion 500 is the movable portion described in FIGS. 7 to 9 for easy understanding, but it may be a different movable portion as shown in FIG. . In the movable portion 500 shown in FIG. 11, the movable portion 50
Two bushings 50 that are perpendicular to each other are provided at 0. In this case, the movable portion 500 can move in the direction of the arrow 1111 by the combined force of the two bushings 50.

As described above, according to the above-mentioned various embodiments and modifications, the voltage is applied between the electrodes and the voltage is removed, so that the movable portion 500 is relatively fixed with respect to the fixed portion 600. The pitch can be moved by a distance.
Therefore, the moving speed of the movable portion 500 is determined by the number of times (cycles) the voltage is applied and removed per unit time. Conversely, the number of times the voltage is applied and removed (cycles)
The movable part 500 can be moved by a required distance by controlling the. Moreover, when the movable portion 500 is made of polycrystalline silicon, the structure is simplified and a movement that is not affected by gravity or inertial force can be obtained. Further, the moving direction is not only horizontal with respect to the fixed portion 600, but also diagonally movable. That is, in the micromachine having the above-mentioned configuration, the movement suitable for the micromachine can be obtained because the movement is easy to control although the structure is simple.

In the above description of the embodiments, the electrodes are made of polycrystalline silicon for easy understanding, but other materials such as phosphor bronze or conductive plastic may be used instead.

Next, a fourth embodiment of the present invention will be described with reference to FIG.
This will be described below with reference to FIG. The micromachine as a minute movable body is provided with a fixed portion 800 in parallel with the movable portion 700, the movable portion 700 is provided with an electrode 111, and the electrode 111 is provided as an elastic support member.
Two rod-shaped spring supports 12 extend to the insulating film 2. The two spring supports 12 are inclined in the circumferential direction non-parallel to the center line 1112, and are evenly arranged on the circumference with the center line 1112 as the center. The fixing portion 800 is composed of a silicon substrate (not shown), and the insulating film 2 is formed on the upper surface thereof.
The electrode 112 covered with is formed.

The operating principle of the above embodiment will be described below with reference to FIGS. 12 (a) and 12 (b). When a voltage is applied between the electrodes 111 and 112, an electrostatic force acts between these electrodes 111 and 112, the spring support 12 is elastically deformed and further tilted in the circumferential direction, so that the electrode 111 moves toward the electrode 112 side. The electrode interval d becomes narrower than when the electrodes are attracted and no voltage is applied. Then, the electrode 111 has the center line 11
12 and rotates in the direction of arrow 1113 (see FIG. 12).
(B)). Then, when the voltage is removed from between the electrodes 111 and 112, the electrode 111 is separated from the electrode 112 and returned to the original state due to the elastic force of the spring support 12 elastically restoring, and the electrode interval d is widened. At this time, the electrode 111 rotates in the direction opposite to the direction of the arrow 1113.

According to the above-described embodiment, the mechanical motion converting means such as gears is not required, and the linear electrostatic force is directly applied in the circumferential direction orthogonal to the direction of the attraction vector (direction of the center line 1112). It is possible to realize a revolutionary micromachine which can generate a rotation vector, and can delicately control the rotation angle by the applied voltage amount, and further has a self-restoring property that returns to the original state when the voltage is cut off.

In the above description of the embodiment, the number of spring support members 12 is two for ease of understanding, but it is needless to say that the number of spring support members may be more than two, and the shape of the support members 12 is not limited to the rod shape. In addition, the support itself does not necessarily need to have elasticity, and various modifications can be made such that the connection between the support and the electrode part is made elastic.

Next, some embodiments to which the present invention is specifically applied will be described below with reference to FIGS. 13 to 16. First, taking the polycrystalline silicon movable body of FIG. 13 as an example, the reason why the polycrystalline silicon movable body moves by the pitch movement of the support portion of the bushing 5 will be described.

The structure of the polycrystalline silicon movable body shown in FIG. 13 will be described below. The polycrystalline silicon plate 4, the bushing 5, the polycrystalline silicon rod 6, the guide bushing 7, and the polycrystalline silicon guide 8 are integrally formed. Bushing 5
Are provided to incline the polycrystalline silicon plate 4 when it is subjected to electrostatic attraction. A cross section taken along line AA ′ of FIG. 13 is shown in FIG.
4 (a) is shown in cross section. Polycrystalline silicon rod 6
Has a bushing 5 at the same height as the polycrystalline silicon plate 4 so that a twist occurs when the polycrystalline silicon plate 4 tilts.
Is formed at a position where it is attached to the support portion of the. Further, the polycrystalline silicon guide 8 is supported by two or more guide bushings 7 and has a function of keeping the polycrystalline silicon plate 4 from being twisted together with the polycrystalline silicon rod 6 when the polycrystalline silicon plate 4 is tilted. The relationship between the insulating film 2 and the polycrystalline silicon movable body is shown in the sectional view of FIG. 14B taken along the line BB ′ of FIG. 13. When receiving electrostatic attraction, bushing 5
And a part of the guide bushing 7 is in contact with the insulating film 2. Only a part of the guide bushing 7 can make electrical contact with the polycrystalline silicon rail 3. All polycrystalline silicon components are doped with donor or acceptor impurities to serve as conductors. Further, the silicon substrate 1 and the polycrystalline silicon component are electrically insulated from each other by an insulating film 2 which does not serve as a sacrifice layer, for example, CVD Si ₃ N ₄ (silicon nitride).

The pitch motion of the supporting portion of the bushing 5 in the polycrystalline silicon movable body of FIG. 13 configured as described above is as shown in FIG. However, in FIG. 5, the cross-sectional view of FIG. 14A is simplified to facilitate the explanation of the pitch movement.

The description starts from the state where no electrostatic attraction acts on the polycrystalline silicon movable body (FIG. 5A).
An AC pulse voltage is applied between the polycrystalline silicon rail 3 and the silicon substrate 1, and electrostatic attraction acts between the polycrystalline silicon movable body and the silicon substrate 1 at the rising edge of the pulse. The polycrystalline silicon plate 4 is attracted toward the substrate, and is in an inclined state around the supporting portion of the bushing 5 (FIG. 5B), and the bushing 5 is a polycrystalline silicon rod centering around the supporting portion of the bushing 5. Due to the twist of 6 (rotational movement), its bottom surface is moved a distance ΔX. The inclination of the polycrystalline silicon plate 4 at this time depends on the magnitude of the electrostatic attractive force applied, and until the end of the polycrystalline silicon plate 4 contacts the insulating film, when the electrostatic attractive force further acts, The polycrystalline silicon plate 4 is bent. Further, since the polycrystalline silicon guide 8 is fixed to the polycrystalline silicon rod 6 by electrostatic attraction, the polycrystalline silicon rod 6 is twisted according to the inclination of the polycrystalline silicon plate 4.

When the electrostatic attraction acting on the polycrystalline silicon movable body is removed (at the falling edge of the pulse), the polycrystalline silicon plate 4 is twisted in the polycrystalline silicon rod 6 and, in some cases, polycrystalline. The force including the flexure generated in the silicon plate 4 causes it to center around the bottom surface of the bushing 5 which is moved by the distance ΔX from the original position (FIG. 5C). At this time, the polycrystalline silicon guide 8
Causes the polycrystalline silicon plate 4 to be raised because the fixing due to the electrostatic attraction is released, and at the same time, moves its position by the distance ΔX. As a result, the repeated movement of the pulse causes the bushing 5 support portion to move by the distance ΔX in a pitch motion. Therefore, the polycrystalline silicon movable body can be moved by an arbitrary distance in proportion to the number of pulses.

Specific examples of the present invention will be described below with reference to the drawings. FIG. 13 shows a first specific example of the polycrystalline silicon movable body according to the present invention. Two polycrystalline silicon rails 3
(Width 20 microns, height 0.3 microns) is 180
It is made of micron. Polycrystalline silicon plate 4, bushing 5, polycrystalline silicon rod 6, guide bushing 7,
The polycrystalline silicon guide 8 is integrally formed of one layer of polycrystalline silicon having a thickness of 1.5 μm and heavily doped with phosphorus. In addition, the polycrystalline silicon movable body made of these is a 0.3 μm thick CVD Si ₃ N film.
_The insulating film 2 made of ₄ electrically insulates the silicon substrate 1.

The bushing 5 (length 80 μm, width 8 μm, height 1.7 μm) is made of polycrystalline silicon plate 4.
(100 micron long, 50 micron wide) was made to tilt when subjected to electrostatic attraction. AA 'in FIG.
14A is shown in the sectional view of FIG.
The polycrystalline silicon rod 6 (10 μm in length and 4 μm in width) is located at the same height as the polycrystalline silicon plate 4 so as to be twisted when the polycrystalline silicon plate 4 is tilted and hung on the supporting portion of the bushing 5. Is formed in. In addition, the polycrystalline silicon guide 8 (80 μm in length and 30 μm in width) is supported by two or more guide bushings 7 (18 μm in length, 8 μm in width, 1.7 μm in height), and the polycrystalline silicon plate. When 4 is tilted, it serves to keep it from being twisted together with the polycrystalline silicon rod 6. The relationship between the insulating film 2 and the polycrystalline silicon movable body is shown in the sectional view of FIG. 14B taken along the line BB ′ of FIG. When the electrostatic attraction is applied, the bottom surface of the bushing 5 and a part of the guide bushing 7 are in contact with the insulating film 2. Only a part of the guide bushing 7 can make electrical contact with the polycrystalline silicon rail 3.

This polycrystalline silicon movable body is, for example, S
This can be realized by a technique for producing a micromachine using polycrystalline silicon as a structural material and using iO ₂ as a sacrificial material. However, if this is left as it is, the polycrystalline silicon movable body will be dislocated from the polycrystalline silicon rail 3 due to the etching of the sacrificial material. Therefore, a mechanism is needed to keep this polycrystalline silicon mover on the polycrystalline silicon rail 3 on the silicon substrate 1 during the etching of the sacrificial material.

In the case of the above-mentioned embodiment, as an example, one thin beam having a width of 4 microns and a length of 50 microns is attached to one polycrystalline silicon guide 8, and one side thereof is covered with the insulating film 2.
The polycrystalline silicon movable body is fixed to the top of the polycrystalline silicon rail 3 by a mechanism utilizing the fact that the beam is broken and cut by the moving force of the polycrystalline silicon movable body which is electrically operated. Stays on top.

In order to operate a polycrystalline silicon movable body having a sufficiently microscopic scale using polycrystalline silicon as a structural material, an AC pulse is simply applied between the silicon substrate 1 and the two polycrystalline silicon rails 3. All that is required is to apply a voltage. For example, single-phase AC (sine wave) 100V, 5
You may give 0 Hz. Then, this polycrystalline silicon movable body repeats the pitch motion that occurs in the support portion of the bushing 5, and along the two polycrystalline silicon rails 3,
Move on the silicon substrate 1 until the rail disappears.

FIG. 15 shows a second specific example of the polycrystalline silicon movable body according to the present invention. The difference from the first specific example is that there is one polycrystalline silicon rail 3 and
That is, two polycrystalline silicon plates 4 sandwich one polycrystalline silicon guide 8 and are formed in the same size at symmetrical positions with the polycrystalline silicon rail 3 as a center line. Further, it is different from the first specific example in that only one polycrystalline silicon rod 6 is connected to each of the two polycrystalline silicon plates 4.

This polycrystalline silicon movable body also moves along the polycrystalline silicon rail 3 by applying an AC pulse voltage between the silicon substrate 1 and the polycrystalline silicon rail 3. At this time, the two polycrystalline silicon plates 4 have the same electric potential, and the support portions of the bushings 5 make pitch motions at the same timing. The two polycrystalline silicon plates 4 move in the same direction and at the same speed. The polycrystalline silicon movable body moves in a proportion exactly to the number of applied pulses.

Further, two or more polycrystalline silicon plates 4 are
It may be a polycrystalline silicon movable body which is connected to one polycrystalline silicon guide 8 and in which the supporting portions of the bushings 5 simultaneously perform a pitch motion.

Further, as in the first specific example, a polycrystalline silicon movable body in which two or more polycrystalline silicon plates 4 are connected to two polycrystalline silicon guides 8 may be used.

The polycrystalline silicon movable body shown in the first concrete example and the second concrete example moves while utilizing the bending generated in the polycrystalline silicon plate 4 in addition to the twist generated in the polycrystalline silicon rod 6. It may be one.

Further, the moving speed of the polycrystalline silicon movable body depends on the mechanical properties and the size of the polycrystalline silicon used as the structural material. That's fine.

FIG. 16 shows a third concrete example of a polycrystalline silicon movable body which is another embodiment of the present invention. In the third specific example, two polycrystalline silicon guides 8 formed in a ring shape and having different diameters are arranged so that their centers are the same, and the polycrystalline silicon plate 4 in the shape shown in the first specific example is interposed therebetween. The bushing 5 and the polycrystalline silicon rod 6 are arranged in two sets in such a manner that the polycrystalline silicon rod 6 is in the radial direction, and they are integrally formed by a single layer of polycrystalline silicon film.

This polycrystalline silicon movable body has a shaft 1
It is formed so that it can rotate about 0, and the inner polycrystalline silicon guide 8 is pressed by a cap 9 so as not to come off from the shaft 10. Therefore, the mechanism using a thin beam at the time of etching the sacrificial material, which is necessary in the first and second specific examples, is not necessary. Further, the outer polycrystalline silicon guide 8 is given a potential from the polycrystalline silicon rail 3 through the guide bushing 7.

The third specific example is provided with two polycrystalline silicon plates 4, but even if only one is provided, the bushing 5 thereof will be used.
This polycrystalline silicon movable body can rotate if the support section makes a pitch motion. Therefore, in this embodiment, the number of the polycrystalline silicon plate 4 integrally formed with the bushing 5 may be at least one.

Even when the outer polycrystalline silicon guide 8 is omitted and only the guide bushing 7 is attached to the end of the outer polycrystalline silicon rod 6, the inner polycrystalline silicon rod 6 is twisted. It can be rotated by means of such a polycrystalline silicon movable body.

As described above, according to the present invention, the silicon substrate 1 is used as the one-sided electrode, and an alternating pulse voltage is applied to the movable body of polycrystalline silicon to move it.

The movable range of the micro polycrystalline silicon movable body can be exerted on the entire surface of the silicon wafer by using the polycrystalline silicon rail 3.

Further, in order to obtain a large electrostatic attraction, it suffices to increase the area of the polycrystalline silicon plate 4 or decrease the height of the bushing 5, and there is no technical complexity.

Further, since the polycrystalline silicon rod 6 is twisted at the rising edge of the pulse and the polycrystalline silicon guide 8 is also attracted to the silicon substrate 1, the polycrystalline silicon movable body is separated from the substrate or deviated from the rail. There is no.

According to the present invention, the movable distance ΔX of the polycrystalline silicon movable body by one pitch movement is very small, but the movable distance can be accurately controlled by the number of pulses to be given. In addition, the moving speed can be changed by changing the frequency or amplitude of the single-phase power supply.

By forming a number of polycrystalline silicon plates 4 in an array with the polycrystalline silicon guide 8 being common, the polycrystalline silicon movable body can be freely moved on the two-dimensional plane of the silicon wafer.

Further, in the case of being configured as a rotating body as in the third specific example, it is possible to configure a micromachine system for transmitting power by coupling with other gears.

[0074]

Since the present invention is configured as described above, not only the wiring and electrode structure but also the structure of the driving mechanism is simple, and the electrostatic force and the elastic force are effectively utilized to efficiently and efficiently apply the mechanical force. Can be converted and transmitted to, and has a control function in itself,
It is possible to provide a minute movable body that can realize a pitching motion and a latch function. Furthermore, by utilizing the elasticity of polycrystalline silicon, it is possible to change the applied electrostatic attraction force to forward movement and form a micro movable body that moves reliably on the silicon wafer. As a result, the entire micromachine can be simplified and downsized, which is very effective in putting the micromachine into practical use.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining an operation principle in the first embodiment of the present invention.

FIG. 3 is an explanatory diagram for explaining a structure and an operating principle of a modified example according to the first embodiment of the present invention.

FIG. 4 is a perspective view showing a configuration of a second embodiment of the present invention.

FIG. 5 is an explanatory diagram for explaining the operation principle of the second embodiment of the present invention.

FIG. 6 is an explanatory diagram for explaining a configuration and an operating principle of a modified example of the second embodiment of the present invention.

FIG. 7 is a perspective view showing the configuration of a third embodiment of the present invention.

FIG. 8 is an explanatory diagram showing the operating principle of the third embodiment of the present invention.

FIG. 9 is an explanatory diagram showing a modification of the third embodiment of the present invention.

FIG. 10 is a perspective view showing a modified example of the third embodiment of the present invention.

FIG. 11 is a perspective view showing a specific example according to the third embodiment of the present invention.

FIG. 12 is an explanatory diagram for explaining a configuration and an operating principle of a fourth embodiment of the present invention.

FIG. 13 is a perspective view showing a configuration of a fifth exemplary embodiment of the present invention.

FIG. 14 is a cross-sectional view showing the configuration of the fifth embodiment of the present invention.

FIG. 15 is a perspective view showing a configuration of a sixth exemplary embodiment of the present invention.

FIG. 16 is a perspective view showing the configuration of a seventh embodiment of the present invention.

FIG. 17 is a conventional example for explaining the present invention.

[Explanation of symbols]

 1 Silicon Substrate 2 Insulating Film 3 Polycrystalline Silicon Rail 4 Polycrystalline Silicon Plate 5, 50 Bushing 51 Bushing Support 52 Bushing Leg 6 Polycrystalline Silicon Rod 7 Guide Bushing 8 Polycrystalline Silicon Guide 9 Cap 10 Shaft 111 Electrode 112 Electrode 113 Electrode 12 Spring Support 121 Elastic Plate 13 Claw 16 Frame 17 Beam 100, 500, 700 Movable Part 200, 600, 800 Fixed Part 300 Drive Mechanism

Claims (3)

[Claims] 1. A micro movable body comprising at least a pair of electrodes and an elastic support member that variably supports an electrode interval between the pair of electrodes by elastic force. 2. An alternating current pulse is applied between a silicon substrate and a polycrystalline silicon plate through an insulating film, and a rising edge of the alternating current pulse gives a twist to a polycrystalline silicon rod which is hung on a bushing support portion of the polycrystalline silicon plate and falls. A minute movable body in which the bushing support part makes a pitch motion by utilizing the fact that the polycrystalline silicon rod twisted in step 3 returns to the original. 3. The micro movable body according to claim 2, wherein the bending of the polycrystalline silicon plate is utilized in addition to the twist of the polycrystalline silicon rod.