JP2006042005A - Electromechanical resonator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromechanical resonator wherein a narrow gap between a vibrator and an electrode is formed with a simple method. <P>SOLUTION: An electrostatic actuator formed on the same substrate is used to obtain a gap formed between the vibrator 202 and the electrode 203 smaller than a minimum gap manufacturable by the semiconductor manufacturing technology, and the vibrator with a greater electrostatic force is excited, or a greater current caused by the vibration is produced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electromechanical resonator, and more particularly to an electromechanical resonator capable of adjusting sensitivity and realizing a high-performance filter circuit in an electric circuit integrated with high density.

  In recent years, as a filter using an electromechanical resonator, a filter that excites a vibrating body with an electrostatic force and converts the vibration into an electric signal again has been proposed (for example, see Non-Patent Document 1). FIG. 14 shows the principle of the conventional mechanical resonator described in Non-Patent Document 1, FIG. 14 (a) is a plan view, and FIG. 14 (b) is a cross-sectional view taken along line AA ′. Show.

  14A and 14B, reference numeral 101 denotes a disk-type vibrating body, which is fixed to the substrate 103 via an anchor 102 located at the center of the disk. Reference numeral 104 denotes an excitation electrode disposed on the half circumference of the disk via the gap g, and reference numeral 105 denotes a detection electrode disposed on the other half circumference via the gap g. In this resonator, a resonance mode (disk contour mode) in which the vibrating body 101 expands and contracts in the radial direction is used. As shown in FIG. 14C, when an AC signal vi is applied between the excitation electrode 104 and the vibrating body 101, an electrostatic force is applied to the vibrating body 101 to excite the vibration, and the vibration amplitude is near the resonance frequency. Maximum. This vibration is detected as the generation of a current i accompanying the capacitance change between the vibrating body 101 and the detection electrode 105, and as a result, a bandpass filter having a pass band near the resonance frequency between the input port in and the output port out. Composed.

  When the disk radius is r, the capacitance between the excitation electrode 104 and the vibrating body 101 is C, and the capacitance between the detection electrode 105 and the vibrating body 101 is C, the electrostatic force F acting on the vibrating body is (several In 1), the current i generated by the vibration of the vibrating body is expressed by (Expression 2).

From (Equation 1) and (Equation 2), as ΔC / Δr increases, the excitation force to the vibrating body increases and the detected current value also increases, so that a filter with high energy conversion efficiency can be configured. Since ΔC / Δr takes a larger value as the value of the gap g is smaller as shown in (Equation 3), it is desirable that the value of g is as small as possible.

  In the electromechanical resonator disclosed in Non-Patent Document 1, the value of the gap g is 100 nm with respect to a disk diameter of 20 μm.

  On the other hand, there is a case where the gap is too small and the sensitivity is large, and the vibration of the vibrating body is attracted to the electrode by the electrostatic force due to the AC signal, and both of them come into contact with each other. It may be necessary to use it lower.

Jing Wang, Zeying Ren, and Clark T.-C. Nguyen, "SELF-ALIGNED 1.14-GHZ VIBRATING RADIAL-MODE DISK RESONATORS", TRANSDUCERS '03, Boston, June 2003, pp.947-950

  However, in the above configuration, a complicated manufacturing process is required to form the gap g. About the area | region B of Fig.14 (a) which shows the said structure, the outline of the manufacturing method is shown in FIG. In FIG. 15, the edge of the detection electrode 105 protrudes above the vibrating body 103 due to a processing problem, but there is no influence because it is sufficiently separated. As shown in FIG. 15A, the first sacrificial layer (silicon oxide film) S1, the vibrator (polysilicon) 101, and the second sacrificial layer (silicon oxide film) are formed on the silicon substrate 103 by a semiconductor manufacturing technique. S2, a third sacrificial layer (silicon oxide film) S3, and an electrode (polysilicon) 105 are sequentially stacked. The sacrificial layer is finally removed with hydrofluoric acid, so that the vibrating body can vibrate, and a gap g determined by the thickness of the third sacrificial layer S3 is formed between the vibrating body 101 and the electrode 105 ( (B) in FIG.

In the manufacturing process shown in FIG. 15, a large number of masks are used to repeatedly form and pattern the first to third sacrificial layers S1 to S3, the vibrating body 101, and the electrodes (104, 105). It was necessary and had the subject that manufacturing cost started. In addition, as the narrower gap g is formed, the etchant wraps around more slowly and the etching speed of the third sacrificial layer S3 is significantly reduced.
In addition, since the characteristics greatly change depending on the size of the gap, it is extremely important to set the size of the gap with high accuracy.
In addition, since the size of the gap is determined by this processing step, it may be necessary to actually adjust the gap.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an electromechanical resonator capable of adjusting a narrow gap between a vibrating body and an electrode with high accuracy by a simple method.

  In order to solve the above-described problems, an electromechanical resonator of the present invention includes a vibrating body that performs mechanical vibration and an electrode that is positioned in proximity to the vibrating body. Position adjustment means for moving and holding the position is provided, and the relative position between the vibrating body and the electrode is adjusted.

That is, the electromechanical resonator of the present invention includes a vibrating body that performs mechanical vibration and an electrode that is disposed at a predetermined interval with respect to the vibrating body, and the vibrating body generates mechanical vibration. An electromechanical resonator configured to be capable of performing electromechanical conversion, characterized by comprising position adjusting means for adjusting the position of the vibrating body or the electrode.
With this configuration, since the relative position between the vibrating body and the electrode can be adjusted by the position adjusting unit, the position adjusting unit does not depend only on the processing accuracy but exceeds the processing limit or after processing. It is possible to adjust the size of the gap by the displacement. In addition, by adjusting the size of the gap in this way, the amplitude of the vibrating body can be amplified or attenuated. This electromechanical resonator has an electromechanical conversion function for converting a voltage change between a vibrating body and an electrode into vibration of the vibrating body, and a change in distance between the vibrating body and the electrode accompanying the vibration of the vibrating body. Is converted into a capacitance change between the vibrating body and the electrode.

In the electromechanical resonator of the present invention, the position adjusting unit may include a drive source that generates a moving force for moving the position of the vibration pair or the electrode, and the relative position between the vibrating body and the electrode may be Includes ones whose position has been adjusted.
With this configuration, the size of the gap can be adjusted in a larger range by dynamically adjusting the relative position between the vibrating body and the electrode by the drive source.

In the electromechanical resonator of the present invention, the vibrator and the electrode are manufactured on the same substrate by using a semiconductor manufacturing technique.
With this configuration, an electromechanical resonator with high accuracy and high reliability can be obtained using a simple semiconductor manufacturing technique.

The electromechanical resonator according to the invention includes one in which the position adjusting means and the driving source are manufactured on the substrate by using a semiconductor manufacturing technique.
With this configuration, significant downsizing can be achieved. Here, the drive source is not limited as long as the drive circuit excluding the power supply is formed on the same substrate, and includes a power supply connected separately.

  Moreover, the electromechanical resonator of the present invention includes one in which the drive source is an electrostatic actuator.

In the electromechanical resonator according to the aspect of the invention, the position adjusting unit may include a beam structure, and the driving source may displace at least one beam of the beam structure by a predetermined amount, thereby Including those configured to realize fine adjustment of the distance from the electrode from g to g ′.
With this configuration, when the distance between the vibrator and the electrode immediately after processing is g, adjustment from g to g ′ is possible, and the excitation force of the vibrator can be set to the square of g / g ′. .

In the electromechanical resonator of the invention, the beam structure includes a comb body and comb teeth that are orthogonal to the comb body and are arranged in parallel to each other, and the comb teeth face each other. A pair of comb-teeth electrodes arranged in this manner, and a beam connected to one comb body of the comb-teeth electrode and displaced in conjunction with the displacement of the comb body.
According to this configuration, the comb body connected to the vibrating body or the electrode is displaced by the electrostatic force of the comb teeth that oppose the vibrator body or electrode. The so-called pull-in phenomenon in which the comb teeth come into contact with each other does not occur because of the meshing depth direction. For this reason, the control range of a gap can be taken large.

The electromechanical resonator according to the invention includes the electromechanical resonator in which the position adjusting unit makes the initial positions of the vibrating body and the electrode variable according to the voltage of the AC signal applied between the vibrating body and the electrode.
According to this configuration, the initial positions of the vibrating body and the electrode can be adjusted by the voltage, and high-precision adjustment can be easily performed.

In the electromechanical resonator of the invention, the position adjusting means includes a plurality of the beam structures.
According to this configuration, the amplitude as described above can be greatly increased by connecting and using a plurality of beam structures.

Moreover, the electromechanical resonator of the present invention includes one including a plurality of electromechanical resonators arranged in parallel electrically.
According to this configuration, there is an effect that it is possible to adjust the intervals between the plurality of stages of vibrating bodies and electrodes with one driving source.

The electromechanical resonator of the present invention includes the electromechanical resonator housed in a case sealed so as to be in a vacuum atmosphere.
According to this configuration, it is possible to form an electromechanical resonator having a long life and low noise.

The filter of the present invention is formed using the above electromechanical resonator.
According to this configuration, a highly sensitive, highly accurate and reliable filter can be obtained.

  The electric circuit of the present invention is formed using the above electromechanical resonator.

According to the configuration of the electromechanical resonator of the present invention, it is possible to easily form an electromechanical resonator having excellent electrical / mechanical and mechanical / electrical conversion efficiency.
According to this configuration, it is possible to form a narrow gap between the vibrator and the electrode by exceeding a normal resolution limit by a simple method. In addition, the size of the gap can be adjusted with high accuracy. Furthermore, by controlling the gap, it is possible to prevent the electrode from being drawn into and contacted with the vibrating body by the electrostatic force generated by the AC power itself, thereby making it impossible to operate.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
FIG. 1 is a perspective view of an electromechanical resonator according to Embodiment 1 of the present invention. The electromechanical resonator is formed from a single silicon substrate by a MEMS process, and includes a vibrating body 202 that performs mechanical vibration, and an electrode that is disposed at a predetermined interval with respect to the vibrating body 202. 203, and a position adjusting means 200 for adjusting the position of the vibrating body 202 or the electrode 203 is provided.
Here, the vibrating body 202 is a doubly-supported beam having both ends fixed on the substrate 201, and 203 is disposed in the vicinity of the vibrating body 202, and is an electrode for exciting the vibrating body or detecting the vibration of the vibrating body. It is. 206 is a position adjusting electrode fixed on the substrate 201, 205 is a position adjusting beam of a doubly supported beam structure whose both ends are fixed on the substrate 201, and the position adjusting electrode 206 and the position adjusting beam 205 are An electrostatic actuator is configured. Reference numeral 204 denotes a connecting beam that transmits the displacement accompanying the driving of the electrostatic actuator to the electrode 203. That is, the position adjusting means is configured by the position adjusting electrode 206, the position adjusting beam 205, the connecting beam 204, and the drive source (drive power source 209 (see FIG. 2B)).

  FIG. 2 is a plan view of the electromechanical resonator of FIG. 1 as viewed from above the substrate. The operation of the electromechanical resonator according to the first embodiment will be described with reference to FIG. In FIG. 2, the hatched part is a fixed part fixed on the substrate, and the other part is a movable part. Since the resonance frequency f of the flexural vibration of the vibrating body 202 in the horizontal direction of the substrate is inversely proportional to the square of the length L as shown in (Expression 4), for example, several tens of MHz to several tens of MHz used for high-frequency wireless transmission. In order to obtain mechanical resonance at a high frequency of GHz, L must be shortened.

  On the other hand, the width W of the vibrating body 202 needs to be narrowed in order to ensure the amount of bending due to vibration, and is almost equal to the minimum line width (several hundred nm to several μm) that can be manufactured using semiconductor manufacturing technology. Therefore, in the example shown in FIG. 2, the width W of the vibrating body 202 is the minimum line width that can be manufactured by the semiconductor manufacturing technology, and the value of the gap between the electrode 203 is also the minimum gap that can be manufactured by the semiconductor manufacturing technology. , Approximately W = g. Similarly, the value of the gap between the position adjusting electrode 206 and the position adjusting beam 205 is also g.

In FIG. 2A, no potential difference is applied between the position adjustment electrode 206 and the position adjustment beam 205, and the value of the gap between the vibrating body 202 and the electrode 203 is g. In FIG. 2B, a potential difference V _drive is applied between the position adjustment electrode 206 and the position adjustment beam 205, and the position adjustment beam 205 is drawn into contact with the position adjustment electrode 206 side by electrostatic force, The held state is shown. At this time, the value of the gap between the vibrating body 202 and the electrode 203 is g ′, which is smaller than the initial value of g. Therefore, it is possible to form a narrow gap that is not limited to the minimum gap g that can be produced by the semiconductor manufacturing technique to be used.

  As described above, since the narrow gap g ′ that cannot be produced by the normal semiconductor manufacturing technology can be obtained, the excitation signal vi is applied to the vibrating body 202 as shown in FIG. 2B, for example. Then, as compared with the case where vi is applied in the state of FIG. 2A, an excitation force that is a square of g / g ′ acts on the vibrating body 202, and a larger vibration amplitude can be obtained.

  Note that the resonance frequency of the structure including all of the position adjustment beam 205, the connecting beam 204, and the electrode 203 is sufficiently separated on the frequency axis as compared with the resonance frequency of the vibration body 202. Although it is possible to suppress the vibration of the position adjusting beam 205, the connecting beam 204, and the electrode 203 at the resonance frequency to be vibrated, when the electromechanical resonator according to the first embodiment of the present invention is reliably realized in the filter. The filter input signal that does not have the resonance frequency of the structure other than the vibrating body 202 in the frequency band is used, or the frequency component generated by the resonance of the structure other than the vibrating body 202 is obtained from the output signal of the filter. What is necessary is just to suppress by the filter comprised with the electric circuit element.

  Next, a method for manufacturing the electromechanical resonator according to the first embodiment of the present invention will be described. FIGS. 3A to 3D are manufacturing process diagrams illustrating a method of manufacturing the electromechanical resonator shown in FIG. 2 by enlarging particularly the vicinity of the vibrator 202 and the electrode 203. The vibrating body 202 and the electrode 203 are formed on the substrate 201. For example, the substrate 201 is a high resistance silicon substrate having a silicon oxide film formed by thermal oxidation and a silicon nitride film formed by a low pressure CVD method deposited on the surface.

  First, as shown in FIG. 3A, a sacrificial layer made of a photoresist is spin-coated on a silicon substrate 201, exposed and developed by photolithography, and then baked on a hot plate to form a sacrificial layer 207.

Next, an aluminum thin film 208 is deposited on the entire surface of the substrate by sputtering (FIG. 3B).
Next, a photoresist is formed on the aluminum thin film 208, patterning is performed by photolithography, and aluminum is etched by using the pattern made of the photoresist as a mask, thereby forming the vibrator 202 and the electrode 203 (FIG. 3). (C)). Further, the photoresist pattern and the sacrificial layer 207 are removed by oxygen plasma. As a result, the vibrating body 202 becomes a doubly supported beam that can vibrate, and forms a capacitor with the electrode 203 (FIG. 3D).

By using this manufacturing method, the electromechanical resonator according to the first embodiment of the present invention can be realized with the two masks for patterning the sacrificial layer 207 and for patterning all the aluminum structures shown in FIG. it can.
Although a high-resistance silicon substrate is used in this embodiment mode, a normal silicon substrate, a compound semiconductor substrate, or an insulating material substrate may be used.
Further, although a silicon oxide film and a silicon nitride film are formed as insulating films on the high resistance silicon substrate 201, the formation of these insulating films may be omitted if the resistance of the substrate is sufficiently high.

  In this embodiment, aluminum is used as a material for forming the vibrator and the electrode. However, other metal materials Mo, Ti, Au, Cu, and semiconductor materials into which impurities are introduced at a high concentration, such as amorphous silicon, poly Silicon, a conductive polymer material, or the like may be used. Further, although sputtering is used as a film forming method, it may be formed using a CVD method, a plating method, or the like.

  Since a natural oxide film is formed on the surface of aluminum used as the structural material, the electrostatic force is maintained even when the position adjusting electrode 206 and the position adjusting beam 205 are in contact with each other in the state shown in FIG. The In order to further improve the insulating properties of the contact surface, a silicon nitride film may be deposited by plasma CVD on the entire surface of the structure composed of an aluminum thin film in the state of FIG.

According to such a configuration, the vibration adjusting body that performs mechanical vibration and the electrode that is positioned in proximity to the vibrating body, and the position adjustment mechanism that moves and holds the position of the vibrating body or the electrode, By adjusting the relative position between the vibrating body and the electrode, a narrow gap between the vibrating body and the electrode can be realized very easily, and a filter having excellent conversion efficiency between the electric machine and the machine electricity is provided. can do.
If adjustment is required during use, the size of the gap can be adjusted by adjusting the drive voltage.

FIG. 4 shows the relationship between the DC voltage V _drive and the gap g. Once the voltage V _raise is _increased to V _pi (pull-in voltage) or more, the position adjusting beam is drawn into contact with the position adjusting electrode. Therefore, although it has a hysteresis characteristic as shown in FIG. 4, g can be controlled by making the voltage V _direction variable between the regions B. Here, it is desirable that g is as small as possible. However, if the AC power injected into the vibrating body is too small, the electrode is drawn into contact with the vibrating body by the electrostatic force of the AC signal itself and becomes inoperable. Sometimes. When the AC power is large, the value of V _drive can be lowered to increase g, thereby avoiding contact.

As described above, in the present embodiment, by changing the potential difference V _drive , the contact region D between the position adjustment electrode 206 and the position adjustment beam 205 in FIG. 2B also changes, so that the gap g ′ It is possible to adjust the value. Vibration of the vibrating body 202 is increased if the input signal v _i a large voltage is applied, the vibration body 202 comes into contact is drawn to the electrode 203, suitably by lowering the voltage V _{where drive} gap g ' It is possible to avoid contact by adjusting the value of slightly larger.

Thus, according to the present invention, it is easy to form a small gap beyond the processing limit. Further, the size of the gap can be adjusted according to the size of the DC voltage V _drive to which the gap is applied, and fine adjustment is facilitated. It is also possible to adjust the gap in the direction of increasing according to the use conditions. In this case, by arranging the position adjusting electrode 206 on the side opposite to the position adjusting beam 205, the size of the gap can be easily adjusted in both directions.

In the present embodiment, the position adjusting beam 205 is drawn and brought into contact with the position adjusting electrode 206 by electrostatic force. However, the position adjusting beam 205 has a value of V _drive equal to or less than a potential difference causing pull-in. 205 may be bent. Alternatively, as shown in FIG. 5, the position adjustment beam 205 may be driven by comb-teeth electrodes provided on both the position adjustment beam 205 and the position adjustment electrode 206.

In this configuration, the position adjustment beam 205 moves in the comb engagement depth direction. FIG. 6 shows the relationship between the DC voltage V _drive and the gap g at this time. As is clear from this relationship curve, the pull-in phenomenon does not occur. Thus, by using the comb-shaped electrode as the position adjusting beam, pull-in does not occur, so that the control range of the gap g can be increased.

  Note that although an example in which the position of the electrode 203 is adjusted has been described in this embodiment, a position adjusting mechanism and a driving power source 209 that is a driving source may be connected to the vibrating body 202 side.

Further, the beam structure having a narrow gap formed in this way can be applied not only to an electromechanical filter but also to various devices as a resonance structure.
Further, since this electromechanical resonator is a fine element, it is desirable to use it in a vacuum case in order to prevent contamination and reduce the viscous resistance of air. Further, in the above-described embodiment, it is formed so as to protrude from the substrate surface. However, since it can be easily formed by MEMS, a recess is formed in the substrate, and the vibrator is configured to extend over the recess. Also good.

(Embodiment 2)
In the first embodiment, the example in which the vibrating body is caused to bend is described. However, as the second embodiment of the present invention, a configuration for causing torsional vibration in the vibrating body will be described.

  In the first embodiment, since the vibrating body 202 and the electrode 203 are formed of a thin film formed on the same plane by the same process, the thickness and the distance from the substrate 201 are equal. Therefore, even if an electrostatic force by an AC signal is applied between them, only the flexural vibration in the horizontal direction of the substrate is excited by the vibrating body 202.

Therefore, in the present embodiment, as shown in FIG. 7, the second position adjusting electrode 210 formed on the substrate 201 is provided so as to face the lower surface of the electrode 203 in order to cause torsional vibration. It is characterized by this. As in the first embodiment, as in the first embodiment, the first driving power source V _drive1 is controlled to _bring the electrode closer to the vibrating body, and when g is reduced, the second position adjusting electrode 210 and the electrode A direct current potential is applied between the second driving power source V _drive2 203 and the electrode 203 is brought into contact with the second position adjusting electrode 210 on the substrate. At this time, since a thin insulating film is formed on the surface of the second position adjusting electrode 210, the contact state is maintained by electrostatic force even after contact.

  FIG. 9 shows a cross section taken along the line a-a ′ of FIG. Since the electrode position is shifted in the −z direction with respect to the vibrating body, the electrostatic force due to the AC signal applied to the vibrating body is concentrated at the lower part of the side wall of the vibrating body. Thereby, torsional vibration can be excited.

(Embodiment 3)
In the first and second embodiments, the position adjusting means of the cantilever beam structure has been described. However, the present embodiment is characterized in that the position adjusting means of the cantilever beam structure is used.
Also in the present embodiment, as in the first embodiment, as shown in FIGS. 10A and 10B, a driving power source 209 is used between the position adjusting beam 205 and the position adjusting electrode 206. Apply voltage. Here, both are pulled in by the DC potential difference V _drive . After pull-in, g ₂ can be controlled by making V _drive variable.

  In this configuration, even if the AC signal injected into the electrode suddenly becomes high power, and the force F2 for pulling the electrode into the vibrating body 202 by the electrostatic force due to the AC signal itself is applied, this AC signal is canceled out. The electrostatic force F <b> 1 by itself also acts between the position adjusting electrode 206. This makes it possible to configure a resonator that is resistant to power changes.

  FIGS. 10A and 10B are plan views of the electromechanical resonator according to the third embodiment of the present invention. 10A and 10B, the hatched part is a fixed part fixed on the substrate, and the other part is a movable part. The electrode 203 is connected to a position adjusting beam 205, one end of the position adjusting beam 205 is fixed to the substrate, and an electrode 203 is provided near the other end. A vibrating body 202 is provided on the electrode 203 with a gap g therebetween.

As shown in FIG. 10B, a DC potential difference V _{drive is} applied between the position adjusting beam 205 and the position adjusting electrode 206 by the driving power source 209 to pull them in. At this time, the gap g2 between the vibrating body 202 and the electrode 203 changes to g2 ′, which is smaller than the initial value of g2. In this way, it is possible to form a narrow gap that is not limited to the minimum gap g that can be produced by the semiconductor manufacturing technique to be used.

  In the present embodiment, one electrode 203 is arranged on the position adjusting beam 205. However, as shown in FIG. 11A, a plurality of pairs of the vibrating body 202 and the electrode 203 may be arranged. . FIG. 11B shows a state in which an electrostatic force is applied between the position adjusting beam 205 and the position adjusting electrode 206 to make contact. At this time, the value of the gap between each vibrating body and the electrode is g1 ′ <g2 ′, and even if the high-voltage excitation signal vi is input and g1 ′ is zero, that is, the contact state is reached, the vibrating body 202b is moved with g2 ′. It is possible to excite.

(Embodiment 4)
FIG. 12 is a plan view of the electromechanical resonator according to the fourth embodiment of the present invention. In FIG. 12, the hatched part is a fixed part fixed on the substrate, and the other part is a movable part. The electrode 203 is connected to a position adjusting mechanism (not shown) and a drive source (not shown).

  The present embodiment is characterized in that the position of the electrode is controlled in the X and Y directions. With this configuration, the gap can be narrowed, the gap g can be controlled so that the electrode and the vibrator are not fixed by the electrostatic force generated by the injected AC signal itself, and the resonance frequency can be adjusted. Become.

  In FIG. 12A, the electrode 203 is moved in the Y direction to come into contact with the vibrating body 202, and further pushed in, thereby forming a gap g ′ smaller than the initial gap g as shown in FIG. . As a result, it is possible to form a narrow gap that is not limited to the minimum gap g that can be produced by the semiconductor manufacturing technique used.

  Further, the degree of freedom in the X direction is also given to the moving mechanism connected to the electrode 203, and the resonance frequency can be changed by changing the position of the fulcrum A shown in FIG. When the vibrating body 202 is polysilicon having a Young's modulus of 165 GPa, the length L is 1 μm, the width W is 100 nm, and the pushing amount d is 10 nm, the position L ′ of the fulcrum A is 0.6 L, 0.7 L, and 0.8 L. When changed, the resonance frequency of the vibrating body 202 changes as shown in FIG. The resonance frequency can be varied from about 0.6 GHz to 0.9 GHz.

  According to such a configuration, it is possible to realize a narrow gap between the vibrating body and the electrode by a simpler method than the conventional example by bringing a part of the vibrating body and a part of the electrode into contact with each other. In addition, a filter having excellent mechanical-electrical conversion efficiency can be provided. In addition, since the resonance frequency can be changed by changing the position of the contact point, it can be used for fine adjustment of the resonance frequency, an adaptive filter or the like that can adaptively change the passband.

  In the above-described embodiment, the example in which the electrode is displaced has been described. However, the vibrating body may be displaced.

  The electromechanical resonator according to the present invention has an effect of simplifying the manufacturing process and providing a filter having excellent electro-mechanical and mechanical-electrical conversion efficiency, and is mounted on a portable wireless terminal. It is useful as a high frequency filter circuit integrated in Further, the present invention can be applied to medical and environmental applications such as spectrum analysis in the voice band and ultrasonic band, and mass analysis by mechanical resonance.

The perspective view of the electromechanical resonator in Embodiment 1 of this invention 1 is a top view of an electromechanical resonator according to Embodiment 1 of the present invention. Manufacturing process diagram of electromechanical resonator according to Embodiment 1 of the present invention The figure which shows the relationship between DC voltage _Vdrive of the electromechanical resonator in Embodiment 1 of this invention, and the gap g. The top view of the electromechanical resonator which used the electrostatic actuator in the modification of Embodiment 1 of this invention and used the comb-tooth electrode. The figure which shows the relationship between a drive voltage and a gap in Embodiment 1 of this invention. The perspective view of the electromechanical resonator in Embodiment 2 of this invention Top view of an electromechanical resonator according to Embodiment 2 of the present invention Explanatory drawing which shows the operation principle of the electromechanical resonator in Embodiment 2 of this invention Top view of an electromechanical resonator according to Embodiment 3 of the present invention Top view showing a modification of the electromechanical resonator according to the third embodiment of the present invention. Top view of an electromechanical resonator according to Embodiment 4 of the present invention Graph showing the relationship between the fulcrum position and the resonance frequency in the fourth embodiment of the present invention Illustration of a filter using a conventional electromechanical resonator Explanatory drawing of the manufacturing method of the conventional electromechanical resonator

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Vibrating body 102 Anchor 103 Substrate 104 Excitation electrode 105 Detection electrode 200 Position adjustment means 201 Substrate 202 Vibrating body 203 Electrode 204 Connecting beam 205 Position adjustment beam 206 Position adjustment electrode 207 Sacrificial layer 208 Aluminum 210 Second position adjustment electrode

Claims (13)

An electromechanical conversion comprising: a vibrating body that performs mechanical vibration; and an electrode disposed at a predetermined interval with respect to the vibrating body, wherein the vibrating body is capable of causing mechanical vibration. An electromechanical resonator that enables
An electromechanical resonator comprising position adjusting means for adjusting the position of the vibrating body or the electrode. The electromechanical resonator according to claim 1,
The position adjusting means includes a drive source that generates a moving force for moving the position of the vibrating body or the electrode, and adjusts the relative position between the vibrating body and the electrode. An electromechanical resonator. The electromechanical resonator according to claim 1 or 2,
A mechanical resonator in which the vibrating body and the electrode are manufactured on the same substrate using a semiconductor manufacturing technique. The electromechanical resonator according to claim 3,
The position adjusting means and the drive source are electromechanical resonators manufactured on the substrate using a semiconductor manufacturing technique. The electromechanical resonator according to claim 2,
An electromechanical resonator in which the driving source is an electrostatic actuator. An electromechanical resonator according to any one of claims 1 to 5,
The position adjusting means includes a beam structure and displaces the vibrating body or the electrode by an amount smaller than the predetermined amount by displacing at least one beam of the beam structure by a predetermined amount by the driving source. And an electromechanical resonator configured to realize fine adjustment. The electromechanical resonator according to claim 6,
The beam structure includes a comb body and comb teeth orthogonal to the comb body and arranged in parallel with each other, and a pair of comb electrodes arranged so that the comb teeth face each other; An electromechanical resonator comprising a beam connected to one comb body of the comb electrode and displaced in conjunction with displacement of the comb body. The electromechanical resonator according to any one of claims 1 to 7,
The position adjusting means is an electromechanical resonator in which the initial positions of the vibrating body and the electrode are variable according to the voltage of the AC signal applied between the vibrating body and the electrode. The electromechanical resonator according to any one of claims 6 to 8,
The electromechanical resonator characterized in that the position adjusting means includes a plurality of the beam structures. The electromechanical resonator according to any one of claims 1 to 9,
A mechanical resonator comprising a plurality of electromechanical resonators arranged in parallel electrically. The electromechanical resonator according to any one of claims 1 to 10,
The electromechanical resonator is housed in a case sealed so as to be in a vacuum atmosphere.   A filter comprising the electromechanical resonator according to claim 1.   An electrical circuit using the electromechanical resonator according to claim 1.

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