JP2008103777A - Micromechanical resonator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To lower the impedance of a micromechanical resonator which has a resonator 5 having both ends supported on a substrate 9 and two electrodes 1 and 2 disposed opposite the resonator 5, where one electrode 1 and resonator 5 face each other to form one or a plurality of gap portions and the other electrode 2 and resonator 5 face each other to form one or a plurality of gap portions. <P>SOLUTION: In the micromechanical resonator, the resonator 5 has a plurality of resonance beams 52, 53, and 54 disposed in mutually parallel position relation on the substrate 9, where both end portions of each resonance beam are supported on the substrate 9 and adjacent resonance beams are coupled to each other at or nearby positions of their antinodes of vibrations. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a resonator that converts an input high-frequency signal into a mechanical signal, and then converts the high-frequency signal back to a high-frequency signal and outputs the same, and more particularly, a micromechanical resonator manufactured using a microfabrication technique in the semiconductor field. It is about.

  In recent years, so-called microelectromechanical system (MEMS) technology has been developed that uses microfabrication technology in the semiconductor field to form a fine mechanical structure integrated with an electronic circuit, and has been applied to filters and resonators. It is being considered.

  FIG. 24 shows a conventional micromechanical resonator using MEMS technology (Non-Patent Document 1). The micromechanical resonator includes a resonator (90) on a substrate (96) as shown in the figure. The support beam is composed of four prismatic support beams (91) to (91), and the base ends of the support beams (91) are respectively mounted on the substrate (96) by anchors (93). It is fixed. Thus, the resonator (90) is held at a position slightly floating from the surface of the substrate (96).

In addition, on both sides of the resonant beam (92) of the resonator (90), an input electrode (94) and an output electrode (95) are disposed across the center of the resonant beam (92), and the resonant beam (92) and A predetermined gap G is formed between the two electrodes (94) 95).
A high frequency power source (6) is connected to the input electrode (94), and a main voltage power source (7) is connected to one anchor (93).

  When a high frequency signal Vi is input to the input electrode (94) in a state where the DC voltage Vp is applied to the resonator (90) through the anchor (93), the input electrode (94) and the resonant beam (92) are placed between them. An alternating electrostatic force is generated through the gap portion G, and the resonator (90) vibrates in a plane parallel to the surface of the substrate (96) by the electrostatic force. Due to the vibration of the resonator (90), the capacitance formed between the resonant beam (92) and both electrodes (95) (94) changes, and the change in the capacitance is caused by the change in the output electrode (95). Is output as a high-frequency signal Io.

  FIG. 25 shows another conventional micro mechanical resonator (Non-Patent Document 2, Patent Document 1). The micromechanical resonator includes a plate-like resonator (100) on a substrate (107), and the resonator (100) has support portions (103) at three places, both end portions and a central portion, A resonant beam (102) is provided between two adjacent supports (103) (103). A support beam (101) protrudes from each support portion (103), and a base end portion of each support beam (101) is fixed to the substrate (107) by an anchor (104). As a result, the resonator (100) is held at a position slightly lifted from the surface of the substrate (107).

On the substrate (107), an input electrode (106) and an output electrode (105) are provided between the two resonant beams (102) and (102) of the resonator (100). A predetermined gap is formed between (102) and the input electrode (106) and between the other resonant beam (102) and the output electrode (105).
A high frequency power source (6) is connected to the input electrode (106), and a main voltage power source (7) is connected to one anchor (104).

  When a high frequency signal Vi is input to the input electrode (106) in a state where the DC voltage Vp is applied to the resonator (100) through the anchor (104), the input electrode (106) and the resonant beam (102) are placed between them. An alternating electrostatic force is generated through the gap, and the resonator (100) vibrates in a plane perpendicular to the surface of the substrate (107) by the electrostatic force. Due to the vibration of the resonator (100), the capacitance formed between the resonator (100) and both electrodes (106) (105) changes, and the change in the capacitance is the output electrode (105). Is output as a high-frequency signal Io.

W.-T.Hsu, JRClark, and CT-C. Nguyen, “Q-optimized lateral freee-free beam micromechanical resonators,” Digest of Technical papers, the 11th Int. Conf. On Solid-State Sensors & Actuators (Transducers '01), Munich, Germany, June 10-14, 2001, pp.1110-1113. M.U.Demirci and C.T.-C.Nguyen, “Higher-mode freee-free beam micromechanical resonators,” Proceedings, 2003 IEEE Int. Frequency Control Symposium, Tampa, May5-8, 2003, pp.810-818. Special Table 2002-535865

  In the micromechanical resonator as described above, in addition to the primary resonance mode shown in FIG. 26A, the secondary resonance mode shown in FIG. 26B and the tertiary resonance mode shown in FIG. However, when micromechanical resonators are applied to high-frequency wireless communication devices operating in the GHz band, the size of the resonators should be reduced in order to facilitate processing during manufacturing. It is necessary to use a higher-order resonance mode that can be increased. However, as shown in FIG. 27, the first-order resonance mode has the highest intensity, the third-order resonance mode, the fifth-order resonance mode, and the higher the order, the lower the intensity. It is.

Thus, as a result of intensive studies to solve the above problems, the present inventors have succeeded in developing a micromechanical resonator that can intentionally generate a higher-order resonance mode.
17 and 18 show an example of the micromechanical resonator. As shown in the figure, the micromechanical resonator includes a resonant beam (52) supported at both ends on a substrate (9) and two electrodes (1) disposed on both sides of the resonant beam (52). (2), between the both ends of the resonant beam (52), one electrode (1) and the resonant beam (52) face each other to form one or a plurality of gaps, The other electrode (2) and the resonant beam (52) face each other to form one or a plurality of gaps, and either one or both of the electrodes (1), (2) and the resonant beam are input by inputting a high frequency signal. An alternating electrostatic force is generated between the resonant beam 52 and the resonant beam 52 to vibrate, and the capacitance between one or both of the electrodes 1, 2 and the resonant beam 52. Is output as a high-frequency signal.

  According to the micromechanical resonator, the resonant beam (52) resonates in a third-order or higher-order resonance mode corresponding to the number of gap portions, and an output signal having a high frequency can be obtained. Therefore, it is not necessary to multiply the frequency of the high-frequency signal to be output. Therefore, in particular, for devices that require low phase noise, such as remote keyless entry systems, RF wireless devices such as spread spectrum communication and software defined radio. It is valid.

By the way, when considering application to such an apparatus, it is required to reduce the impedance of the micromechanical resonator to suppress the loss as much as possible.
Accordingly, an object of the present invention is to further reduce the impedance of the micromechanical resonator developed by the inventors.

The micromechanical resonator according to the present invention includes a resonator (5) whose both ends are supported on a substrate (9), and two electrodes (1) and (2) disposed opposite to the resonator (5). ), One electrode (1) and the resonator (5) face each other to form one or a plurality of gaps, and the other electrode (2) and the resonator (5) Opposite to each other, one or a plurality of gaps are formed, and an alternating electrostatic force is generated between one or both electrodes (1), (2) and the resonator (5) by inputting a high frequency signal. A vibration is applied to the resonator (5), and a change in capacitance between one or both of the electrodes (1), (2) and the resonator (5) is output as a high-frequency signal.
Here, the resonator (5) includes a plurality of resonance beams arranged in parallel with each other on the substrate (9), and both ends of each resonance beam are supported on the substrate, Adjacent resonant beams are connected to each other at or near the antinodes of each vibration.

  In the micromechanical resonator according to the present invention, the plurality of resonance beams constituting the resonator (5) are perpendicular to or parallel to the plane on which these resonance beams are arranged. Electrostatic force is applied to the.

  According to the micromechanical resonator of the present invention described above, the resonator (5) is compared with a case where a plurality of micromechanical resonators each having a resonator composed of a single resonant beam are simply electrically connected in parallel. It has been experimentally confirmed that the mechanical amplitude of each of the constituting resonant beams increases and the Q value increases.

Specifically, the plurality of resonance beams constituting the resonator (5) have shapes and dimensions that make their resonance frequencies different from each other. For example, the plurality of resonant beams constituting the resonator (5) have different lengths.
According to the specific configuration, it has been experimentally confirmed that the Q value is further increased.

Here, if the ratio of the length of the longer resonance beam to the length of the shorter one of the two adjacent resonance beams is less than 1.2, the resonator (5) is the same. It has been experimentally confirmed that the Q value is increased as compared with the case of a plurality of resonant beams having a size.
Further, if the ratio of the length of the longer resonance beam to the length of the shorter resonance beam of the two adjacent resonance beams is in the range of about 1.01 to about 1.02, Q The value can be maximized.

  According to the micromechanical resonator according to the present invention, the Q value can be increased to reduce the impedance.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
In the micromechanical resonator according to the present invention, a resonator (5) made of a conductive material such as silicon or aluminum is disposed on a substrate (9) made of silicon or glass as shown in FIG. It is supported on the substrate (9) by anchors (3) (3) made of a conductive material such as silicon or aluminum. Thus, the resonator (5) is held at a position slightly lifted from the surface of the substrate (9).

  The resonator (5) includes three resonant beams (52) (53) (54) arranged in parallel with each other, and both ends of each resonant beam are connected to the anchors (3) (3). ing. The three resonant beams (52), (53), and (54) are connected to each other by a connecting beam (41) made of a conductive material such as silicon or aluminum at the center of the beam.

Two electrodes (1) (1) (1) made of a conductive material such as silicon or aluminum are disposed below the substrate (9) with the three resonant beams (52) (53) (54) of the resonator (5) interposed therebetween. 1) is provided, and one electrode (2) made of a conductive material such as silicon or aluminum is provided above the opposite side of the substrate (9). These electrodes (1) (1) (2) are connected to each other on the substrate (9). Each lower electrode (1) is formed with an electrode protrusion (16) crossing three resonant beams (52), (53) and (54), and the upper electrode (2) has three resonances. Electrode protrusions (26) crossing the beams (52), (53), and (54) are formed, and these electrode protrusions (16), (26), and (26) are alternately arranged at equal intervals in a misaligned positional relationship. .
A high frequency power source (6) is connected to the electrodes (1), (1) and (2), and a main voltage power source (7) is connected to one anchor (3).

A high-frequency signal Vi is applied from the high-frequency power source (6) to the electrodes (1), (1), and (2) in a state where the DC voltage Vp is applied from the main voltage power source (7) to the resonator (5) via the anchor (3). When input, an alternating electrostatic force is generated between the three resonant beams (52) (53) (54) and the electrode protrusions (16), (26) and (26) via the gap, and the electrostatic force causes 3 The resonant beams (52), (53) and (54) of the book vibrate in a plane perpendicular to the surface of the substrate (9).
Due to the vibration of this resonant beam (52) (53) (54), the capacitance between the resonant beam (52) (53) (54) and the electrode protrusion (16) (26) (26) changes, The change in capacitance is output as a high-frequency signal Io from the anchor (3).

  Here, the three resonance beams (52) (53) (53) constituting the resonator (5) vibrate in the third-order resonance mode. Since they are mechanically connected to each other at the antinode position by the connecting beam (41), the resonator (5) resonates at one resonance frequency as a whole.

The micromechanical resonator has a configuration in which three resonator elements each independently including three beams (52), (53), and (54) are mechanically connected in parallel with each other. However, the micromechanical resonator (connected micromechanical resonator) of the present invention vibrates with a mechanical amplitude larger than that of a micromechanical resonator (single micromechanical resonator) composed of one resonator element. .
A current value obtained by adding the output currents obtained by the three resonator elements is output as a high-frequency signal.

FIG. 2 shows the frequency characteristics Pa, Pb, and Pc of three single-type micromechanical resonators and the frequency characteristics of a coupled-type micromechanical resonator formed by connecting the resonator elements of the three single-type micromechanical resonators. This is a comparison with Pm.
As shown in the figure, the magnitude of the mechanical amplitude of the frequency characteristic Pm of the coupled micromechanical resonator of the present invention is larger than the mechanical amplitude of any of the frequency characteristics Pa, Pb, and Pc of the three individual micromechanical resonators. It is getting bigger.
Therefore, according to the coupled micromechanical resonator of the present invention, an output current larger than the current value obtained by adding the three output currents obtained by the three individual micromechanical resonators can be obtained. Impedance can be reduced.

  Next, various embodiments of the coupled micromechanical resonator of the present invention and the results of mode analysis and static analysis using computer simulation in each embodiment will be described with reference to FIGS.

First Embodiment In the first embodiment shown in FIG. 3, two resonant beams (52) (53) are arranged on a substrate in parallel with the substrate, and these resonant beams (52) (53) are arranged on the upper surface and A laterally-coupled resonator (5) is constituted by coupling with each other by coupling beams (41) and (41) at the center position of the lower surface.
In the resonator (5), as shown in FIG. 4, electrostatic charges in opposite directions are arranged at the center and both ends of each resonance beam (52) (53) in the arrangement direction of both resonance beams (52) (53). The forces P1 and P2 are applied to generate a third-order resonance mode in both resonance beams (52) and (53) as indicated by dotted lines in the figure.
Here, the electrostatic force P1 applied to the central part of the resonant beams (52) (53) (54) is set smaller than the electrostatic force P2 applied to both ends of the resonant beams (52) (53) (54). ing.

In the computer simulation, as shown in FIG. 5, the first resonant beam having a unit length of 5 μm with the interval between two nodes of the vibration of the third-order resonance mode generated in the resonant beam as a unit length, and the resonance In the combination of the second resonance beams in which the unit length of the beam was gradually changed, the change in the Q value of the coupled micromechanical resonator was examined.
As a result, as shown in the figure, the Q value of the coupled micromechanical resonator having the same size of the two resonator elements is larger than the Q value of the single micromechanical resonator (“one” in the figure). It became a thing.

Furthermore, the Q value of the coupled micromechanical resonator having two resonator elements of different sizes is equal to the unit of the second resonant beam with respect to the Q value of the coupled micromechanical resonator having the same size of the two resonator elements. When the length was in the range of 5 μm to 5.1 μm, the value was larger, and the unit length of the second resonance beam was the maximum value at 5.06 μm.
Therefore, the ratio of the length of the longer resonant beam to the length of the shorter resonant beam of the two resonant beams is preferably less than 1.02, and the length of the shorter resonant beam is further reduced. Most preferably, the ratio of the length of the longer resonant beam to the length is about 1.012.

Second Embodiment In the second embodiment shown in FIG. 6, three resonant beams (52) (53) (54) are arranged on a substrate in parallel with the substrate, and these resonant beams (52) (53) are arranged. (54) are connected to each other by connecting beams (41) and (41) at the center positions of the upper surface and the lower surface to form a horizontal three-connected resonator (5).
In the resonator (5), as shown in FIG. 7, in the arrangement direction of the three resonant beams (52), (53), and (54), the central portion of each resonant beam (52), (53), and (54) Electrostatic forces P1 and P2 that are opposite to each other are applied to both ends to generate a third-order resonance mode in the three resonance beams (52), (53), and (54) as indicated by dotted lines in the figure.
Here, the electrostatic force P1 applied to the central part of the resonant beams (52) (53) (54) is set smaller than the electrostatic force P2 applied to both ends of the resonant beams (52) (53) (54). ing.

In the computer simulation, as shown in FIG. 8, a first resonance beam A having a unit length of 5 μm, a second resonance beam B in which the unit length of the resonance beam is gradually changed, and each resonance The change in the Q value of the coupled micromechanical resonator having the combination with the third resonant beam C in which the unit length was changed by the same amount as the beam B was examined.
As a result, as shown in the figure, the Q value of the coupled micromechanical resonator having the same size of the three resonator elements is larger than the Q value of the single micromechanical resonator (“one case” in the figure). It became a thing.

Furthermore, the Q value of the coupled micromechanical resonator having three resonator element sizes different from each other is the unit of the second resonant beam with respect to the Q value of the coupled micromechanical resonator having the same three resonator element sizes. When the length is in the range of 5 μm to 5.1 μm and the unit length of the third resonance beam is in the range of 5 μm to 5.2 μm, the value becomes larger, and the unit length of the second resonance beam is further increased. The maximum value was 5.09 μm, and the unit length of the third resonance beam was 5.18 μm.
Accordingly, the ratio of the length of the longer resonant beam to the length of the shorter resonant beam of the two adjacent resonant beams is preferably in the range of 1 to 1.02, and moreover, It can be said that the ratio of the length of the longer resonant beam to the length of the shorter resonant beam among the resonant beams is most preferably about 1.018.

Third Embodiment In the third embodiment shown in FIG. 9, three resonant beams (52) (53) (54) are arranged on the substrate perpendicular to the substrate, and the center positions of the respective resonant beams in the length direction are arranged. Are coupled to each other by coupled beams (41) and (41) to form a vertical three-coupled resonator (5).
In the resonator (5), as shown in FIG. 10, each resonant beam (52) (53) (54) is oriented in a direction orthogonal to the arrangement direction of the three resonant beams (52) (53) (54). The electrostatic forces P1 and P2 that are opposite to each other are applied to the center and both ends of each of the three resonance beams (52), (53), and (54) as shown by the dotted lines in the figure. generate.
Here, the electrostatic force P1 applied to the central part of the resonant beams (52) (53) (54) is set smaller than the electrostatic force P2 applied to both ends of the resonant beams (52) (53) (54). ing.

  In the computer simulation, as shown in FIG. 11, a first resonance beam A having a unit length of 5 μm, a second resonance beam B in which the unit length of the resonance beam is gradually changed, and each resonance The change in the Q value of the coupled micromechanical resonator having the combination with the third resonant beam C in which the unit length was changed by the same amount as the beam B was examined.

As a result, the Q value of the coupled micromechanical resonator in which the sizes of the three resonator elements are different from the Q value of the coupled micromechanical resonator in which the size of the three resonator elements is the same as that of the second resonant beam. When the unit length is in the range of 5 μm to 5.12 μm and the unit length of the third resonance beam is in the range of 5 μm to 5.24 μm, the value is larger, and the unit length of the second resonance beam is further increased. Was 5.09 μm, and the unit length of the third resonance beam was 5.18 μm, which was the maximum value.
Therefore, the ratio of the length of the longer resonant beam to the length of the shorter resonant beam of the two adjacent resonant beams is preferably in the range of 1 to 1.024. It can be said that the ratio of the length of the longer resonant beam to the length of the shorter resonant beam among the resonant beams is most preferably about 1.018.

Fourth Embodiment FIG. 12 (a) (b), respectively, in the vertical 2 connected resonators and vertical 3 coupled resonators, both ends of the electrostatic force P1 and each resonator beam to be applied to the central portion of each resonator beam The change of the Q value when the electrostatic force P2 applied to the part is equalized is shown.
As shown in FIG. 12 (a), in a vertically connected resonator, the ratio of the length of the longer resonance beam to the length of the shorter resonance beam of two adjacent resonance beams is 1 The range of ˜1.024 is preferred, and it can be said that the ratio of the length of the longer resonant beam to the length of the shorter resonant beam is most preferably about 1.024.
Also, as shown in FIG. 12B, in the vertical three-coupled resonator, the ratio of the length of the longer resonant beam to the length of the shorter resonant beam of the two adjacent resonant beams is 1 to 1.024 is preferable, and the ratio of the length of the longer resonant beam to the length of the shorter resonant beam is most preferably about 1.018.

  From the results shown in FIG. 12, in the coupled micromechanical resonator of the present invention, when the electrostatic force P2 applied to both ends of each resonance beam is set larger than the electrostatic force P1 applied to the center portion of each resonance beam. It can be said that the same effect can be obtained when the electrostatic forces P1 and P2 are equalized.

Fifth Embodiment FIGS. 13 to 15 show an embodiment in which a resonator is vibrated in a primary resonance mode in a micromechanical resonator having vertical three-connected resonators. FIGS. 16 (a) and 16 (b) respectively show an electrostatic force acting on the central part of each resonance beam in a vertical two-connected resonator and a vertical three-connected resonator, and the resonator vibrates in the primary resonance mode. The change of the Q value when it is made to represent is shown.
FIG. 13 shows the size and shape of each resonant beam. FIG. 14 shows the unit length L of each beam for the type A resonant beam (52), the type B resonant beam (53), and the type C resonant beam (54) for each experiment number. FIG. 15 shows the geometry of the connection beam (41) and the position and size of the external force in the vertical three-connection resonator.
It should be noted that only the type A resonance beam (52) and the type B resonance beam (53) were used in the vertical two-connected resonator.

As shown in FIG. 16A, in the case of the vertically connected resonators, the Q value increases when the unit length L of the resonance beam 53 of type B is in the range of 5 μm to 6.8 μm, and is about 6.2 μm. The Q value is the maximum. In addition, in the vertical three-connected resonator, as shown in FIG. 16B, the Q value increases when the unit length L of the resonance beam 53 of type C is in the range of 5 μm to 6.6 μm, and is about 5 The Q value is maximum at 0.8 μm.
Therefore, the coupled micromechanical resonator according to the present invention is not limited to the configuration in which each resonance beam is oscillated in the third or higher order resonance mode, but the configuration in which each resonance beam is oscillated in the first resonance mode. Even so, it can be said that the same effect can be obtained.

FIGS. 17 to 23 show specific configuration examples of one resonator element for generating a higher-order mode that should constitute the coupled micromechanical resonator according to the present invention. In the following description, the resonator, the various electrodes, and the power source are common to a plurality of resonator elements, and the resonance beam of each resonator element is represented by a resonance beam (52).
In the resonator element shown in FIGS. 17 and 18, a resonator (5) made of a conductive material such as silicon or aluminum is disposed on a substrate (9) made of silicon or glass, and the resonator element shown in FIG. On both sides of the resonator (5), a pair of drive electrodes (1) and (2) made of a conductive material such as silicon and aluminum are provided.

The resonator (5) includes a prismatic resonant beam (52) having a length of, for example, 10 to 20 μm, and a pair of support beams (51) (51) (projected parallel to both ends of the resonant beam (52)). 51) and the whole is formed in an H shape. In the resonant beam (52), constricted portions are recessed at equal intervals at seven locations in the longitudinal direction. Both ends of each support beam (51) are fixed to the surface of the substrate (9) by anchors (3) made of a conductive material such as silicon and aluminum, whereby the resonator (5) It is held at a position slightly lifted from the surface of (9).
In addition, a pair of bias electrodes (4) and (4) are arranged outside the both support beams (51) and (51) of the resonator (5) so as to face the central portion of the support beam (51). A predetermined gap (for example, 0.1 to 0.5 μm) is formed between the support beam 51 and the bias electrode 4.

Each of the pair of drive electrodes (1) and (2) has a base part (11) (21) and three electrode protrusions protruding from the base part (11) (21) toward the resonance beam (52) at equal intervals. The parts (10) and (20) have a comb-like shape as a whole.
The three electrode protrusions (10), (10), and (10) of one drive electrode (1) and the three electrode protrusions (20), (20), and (20) of the other drive electrode (2) are each a substrate ( 9) In a plane parallel to the surface of the resonance beam (52), it is alternately opposed to the non-constricted portion of the resonant beam (52), and between the non-constricted portion of the resonant beam (52) (for example, 0.1 to 0.5 μm). ) Gap portion G is formed.

As shown in FIG. 18, a high frequency power source (6) is connected to a pair of drive electrodes (1) and (2), and a main voltage power source (7) is connected to one anchor (3). A bias voltage power source (8) is connected to the pair of bias electrodes (4) (4).
Thus, in the resonator element shown in FIGS. 17 and 18, a high frequency signal is input from the high frequency power source (6) to the two drive electrodes (1) and (2), and the high frequency signal Io is output from one anchor (3). 1-port type resonator element is output.

In the above resonator element, when a high frequency signal is input to both the drive electrodes (1) and (2) in a state where the DC voltage Vp is applied to the resonator (5) via the anchor (3), the electrode protrusions (10 ) (20) and a non-constricted portion of the support beam (51) generate an electrostatic force. Due to this electrostatic force, the resonant beam (52) of the resonator (5) is supported at both ends by the support portion (50). ) (50), it vibrates in a plane parallel to the surface of the substrate (9).
As described above, the electrostatic force to be generated between the electrode protrusions (10) and (20) and the non-constricted portion of the resonant beam (52) is the smallest in the gap near the center of the resonant beam (52) and The gap is set to be the largest in the gap near the both ends.

  The resonance beam (52) of the resonator (5) vibrates with the constricted portion as a vibration node and the non-constricted portion as an antinode of vibration. With this vibration, the resonant beam (52) and both drive electrodes (1) are vibrated. ) And (2) change in capacitance, and the change in capacitance is output as a high-frequency signal Io from the other anchor (3).

Here, by applying a bias voltage to the bias electrodes (4) and (4), an electrostatic force is generated between the support beams (51) and (51) of the resonator (5) and the bias electrodes (4) and (4). This causes the resonant beam (52) of the resonator (5) to receive a tensile force in the longitudinal direction.
Therefore, the resonant frequency of the resonant beam (52) can be changed by adjusting the bias voltage of the bias voltage power supply (8).

In the resonator element shown in FIG. 19, a resonator (5) made of a conductive material such as silicon or aluminum is disposed on a substrate (9) made of silicon or glass, and the resonator ( On both sides of 5), an input electrode (22) and an output electrode (12) made of a conductive material such as silicon or aluminum are provided.

  The resonator (5) has the same structure as that of the first configuration example. The resonator (5) is opposed to the central portion of the support beam (51) on the outside of the support beams (51) and (51). A pair of bias electrodes (4) and (4) is provided, and a predetermined gap (for example, 0.1 to 0.5 μm) is formed between the support beam (51) and the bias electrode (4). Yes.

Each of the input electrode (22) and the output electrode (12) includes a base (23) (13) and three electrodes projecting at equal intervals from the base (23) (13) toward the resonance beam (52). The projecting portions (24) and (14) are provided, and the whole has a comb-teeth shape.
The three electrode protrusions (24), (24) and (24) of the input electrode (22) and the three electrode protrusions (14), (14) and (14) of the output electrode (12) are the surfaces of the substrate (9), respectively. In a plane parallel to the non-necked portion of the resonant beam (52) and a predetermined gap (for example, 0.1 to 0.5 μm) between the non-necked portion of the resonant beam (52). G is formed.

A high frequency power source (6) is connected to the input electrode (22), and a main voltage power source (7) is connected to one anchor (3). A bias voltage power source (8) is connected to the pair of bias electrodes (4) (4).
Thus, the resonator element shown in FIG. 19 is a two-port type resonance in which a high frequency signal is input from the high frequency power source (6) to the input electrode (22) and a high frequency signal Io is output from the output electrode (12). Make up the vessel.

In the above resonator element, when a high frequency signal is input to the input electrode (22) with the DC voltage Vp applied to the resonator (5) via the anchor (3), the electrode protrusion (24) and the support beam An electrostatic force is generated between the non-constricted portion of (51), and this electrostatic force causes the resonant beam (52) of the resonator (5) to be formed on both ends of the substrate as support portions (50) and (50). It will vibrate in a plane parallel to the surface of (9).
As described above, the electrostatic force to be generated between the electrode protrusion (10) and the non-constricted portion of the resonant beam (52) is the smallest in the gap near the center of the resonant beam (52) and near both ends. It is set to be the largest in the gap portion.

  The resonant beam (52) of the resonator (5) vibrates with the constricted part serving as a vibration node and the non-constricted part serving as an antinode, and along with this vibration, the resonant beam (52) and the output electrode (12). The electrostatic capacity formed between the output electrode 12 and the output electrode 12 is output as a high-frequency signal Io.

Here, by applying a bias voltage to the bias electrodes (4) and (4), an electrostatic force is generated between the support beams (51) and (51) of the resonator (5) and the bias electrodes (4) and (4). This causes the resonant beam (52) of the resonator (5) to receive a tensile force in the longitudinal direction.
Therefore, the resonant frequency of the resonant beam (52) can be changed by adjusting the bias voltage of the bias voltage power supply (8).

In the resonator element shown in FIG. 20, a resonator (5) made of a conductive material such as silicon or aluminum is disposed on a substrate (9) made of silicon or glass, and the resonator ( On both sides of 5), a pair of drive electrodes (15), (25) made of a conductive material such as silicon or aluminum is provided.

  The resonator (5) has the same structure as that of the first configuration example. The resonator (5) is opposed to the central portion of the support beam (51) on the outside of the support beams (51) and (51). A pair of bias electrodes (4) and (4) is provided, and a predetermined gap (for example, 0.1 to 0.5 μm) is formed between the support beam (51) and the bias electrode (4). Yes.

One drive electrode (15) has three electrode protrusions (16), (16), which protrude at equal intervals below the resonance beam (52), that is, between the resonance beam (52) and the substrate (9). 16), and the other drive electrode (25) includes three electrode protrusions (26), (26), (26) protruding upward at equal intervals toward the resonance beam (52).
The three electrode protrusions (16), (16), (16) of one drive electrode (15) and the three electrode protrusions (26), (26), (26) of the other drive electrode (25) are each a substrate ( 9) In a plane perpendicular to the surface of the resonant beam (52), it is alternately opposed to the non-constricted portion of the resonant beam (52), and between the non-constricted portion of the resonant beam (52) (for example, 0.1 to 0.5 μm). ) Is formed.

A high frequency power source (6) is connected to the pair of drive electrodes (15) and (25), and a main voltage power source (7) is connected to one anchor (3). A bias voltage power source (8) is connected to the pair of bias electrodes (4) (4).
Thus, in the resonator element shown in FIG. 20, a high frequency signal is input from the high frequency power source (6) to the two drive electrodes (15) and (25), and a high frequency signal Io is output from one anchor (3). 1-port type resonator element.

In the above resonator element, when a DC voltage Vp is applied to the resonator (5) via the anchor (3) and a high frequency signal is input to both the drive electrodes (15) and (25), the electrode protrusions (16 ) (26) and a non-constricted portion of the support beam (51), an electrostatic force is generated. By this electrostatic force, the resonance beam (52) of the resonator (5) is supported at both ends by the support portion (50). ) (50), it vibrates in a plane perpendicular to the surface of the substrate (9).
As described above, the electrostatic force to be generated between the electrode protrusions (16), (26) and the non-constricted portion of the resonant beam (52) is the smallest in the gap near the center of the resonant beam (52) and The gap is set to be the largest in the gap near the both ends.

  As shown in FIG. 21, the resonance beam (52) of the resonator (5) vibrates with the constricted portion serving as a vibration node and the non-constricted portion serving as an antinode of vibration. ) And the drive electrodes (1) and (2) change, and the change in capacitance is output as a high-frequency signal Io from the other anchor (3).

Here, by applying a bias voltage to the bias electrodes (4) and (4), an electrostatic force is generated between the support beams (51) and (51) of the resonator (5) and the bias electrodes (4) and (4). This causes the resonant beam (52) of the resonator (5) to receive a tensile force in the longitudinal direction.
Therefore, the resonant frequency of the resonant beam (52) can be changed by adjusting the bias voltage of the bias voltage power supply (8).

In the resonator element shown in FIG. 22, a resonator (5) made of a conductive material such as silicon or aluminum is disposed on a substrate (9) made of silicon or glass, and the resonator ( On both sides of 5), an input electrode (27) and an output electrode (17) made of a conductive material such as silicon or aluminum are provided.

  The resonator (5) has the same structure as that of the first configuration example. The resonator (5) is opposed to the central portion of the support beam (51) on the outside of the support beams (51) and (51). A pair of bias electrodes (4) and (4) is provided, and a predetermined gap (for example, 0.1 to 0.5 μm) is formed between the support beam (51) and the bias electrode (4). Yes.

  The input electrode (27) and the output electrode (17) each have three electrode protrusions (28) protruding at equal intervals below the resonance beam (52), that is, between the resonance beam (52) and the substrate (9). ) (18), and these electrode protrusions (28) and (18) are alternately opposed to the non-constricted portions of the resonant beam (52) in a plane perpendicular to the surface of the substrate (9). A predetermined gap (for example, 0.1 to 0.5 μm) is formed between the resonance beam 52 and the non-constricted portion.

A high frequency power source (6) is connected to the input electrode (27), and a main voltage power source (7) is connected to one anchor (3). A bias voltage power source (8) is connected to the pair of bias electrodes (4) (4).
Thus, the resonator element shown in FIG. 22 is a two-port type resonance in which a high frequency signal is input from the high frequency power source (6) to the input electrode (27) and a high frequency signal Io is output from the output electrode (17). It constitutes the vessel element.

In the above resonator element, when a high frequency signal is input to the input electrode (27) with the DC voltage Vp applied to the resonator (5) via the anchor (3), the electrode protrusion (28) and the support beam An electrostatic force is generated between the non-constricted portion of (51), and this electrostatic force causes the resonant beam (52) of the resonator (5) to be formed on both ends of the substrate as support portions (50) and (50). It will vibrate in a plane perpendicular to the surface of (9).
The electrostatic force to be generated between the electrode protrusion (28) and the non-constricted portion of the resonant beam (52) is the smallest in the gap near the center of the resonant beam (52) and near both ends as described above. It is set to be the largest in the gap portion.

  As shown in FIG. 23, the resonance beam (52) of the resonator (5) vibrates with the constricted portion serving as a vibration node and the non-constricted portion serving as a vibration antinode, and the resonance beam (52 ) And the output electrode (17) change, and the change in capacitance is output from the output electrode (17) as a high-frequency signal Io.

Here, by applying a bias voltage to the bias electrodes (4) and (4), an electrostatic force is generated between the support beams (51) and (51) of the resonator (5) and the bias electrodes (4) and (4). This causes the resonant beam (52) of the resonator (5) to receive a tensile force in the longitudinal direction.
Therefore, the resonant frequency of the resonant beam (52) can be changed by adjusting the bias voltage of the bias voltage power supply (8).

The micromechanical resonator according to the present invention is configured by arranging a plurality of resonator elements having the above-described various configurations in a horizontal or vertical form on a substrate and connecting them together by a connecting beam. The micromechanical resonator of the present invention shown in FIG. 1 is a horizontal three-connected micromechanical resonator, but the direction of external force is perpendicular to the substrate.
According to such a coupled micromechanical resonator, the Q value is increased as compared with a configuration in which a plurality of individual micromechanical resonators are simply electrically connected, and the loss of the entire resonator can be reduced.

  In addition, since the higher-order mode vibration can be intentionally generated in the resonator (5), a higher oscillation frequency than that of the prior art can be obtained while maintaining the resonator (5) in a size that is easy to manufacture. . Further, by adjusting the voltage of the bias voltage power supply (8), the resonance frequency can be changed without changing the shape of the resonator (5).

  In addition, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim. For example, it is possible to realize a higher oscillation frequency by using a material having a high Young's modulus, such as diamond, as the material of the resonator (5). In the above configuration example, the electrodes have a comb-like shape, but a configuration in which a plurality of electrode protrusions (electrode pieces) are connected to each other by a conductive line may be employed.

It is a perspective view which shows the structure of the micro mechanical resonator which concerns on this invention. It is a graph which shows the frequency characteristic of a connection type | mold micro mechanical resonator and a single type | mold micro mechanical resonator. 1 is a perspective view showing a first embodiment of a micromechanical resonator according to the present invention. It is a figure explaining the action direction of the electrostatic force in 1st Example. It is a graph which shows the change of Q value according to the change of the unit length of the resonant beam in 1st Example. It is a perspective view which shows 2nd Example of the micro mechanical resonator which concerns on this invention. It is a figure explaining the action direction of the electrostatic force in 2nd Example. It is a graph which shows the change of Q value according to the change of the unit length of the resonant beam in 2nd Example. It is a perspective view which shows 3rd Example of the micro mechanical resonator which concerns on this invention. It is a figure explaining the action direction of the electrostatic force in 3rd Example. It is a graph which shows the change of Q value according to the change of the unit length of the resonant beam in 3rd Example. It is a graph which shows the change of Q value according to the change of the unit length of the resonant beam in 4th Example. It is a figure which shows the geometrical dimension of the resonant beam in 5th Example. It is a graph which shows the unit length of the resonant beam of each experiment in 5th Example. It is a figure which shows the shape dimension of the connection beam in 5th Example. It is a graph which shows the change of Q value according to the change of the unit length of the resonant beam in 5th Example. It is a perspective view of the resonator element of the 1st structural example which should comprise the micro mechanical resonator of this invention. It is a top view of the resonator element of the 1st example of composition. It is a top view of the resonator element of the 2nd example of composition. It is a top view of the resonator element of the 3rd example of composition. It is sectional drawing explaining the vibration state of the resonant beam in the resonator element of the 3rd structural example. It is a top view of the resonator element of the 4th example of composition. It is sectional drawing explaining the vibration state of the resonant beam in the resonator element of the 4th structural example. It is a perspective view of the conventional micro mechanical resonator. It is a perspective view of the other conventional micro mechanical resonator. It is a figure explaining a resonance mode. It is a graph showing the frequency characteristic of a primary resonance mode and a high-order resonance mode.

Explanation of symbols

(1) Electrode
(16) Electrode protrusion
(2) Electrode
(26) Electrode protrusion
(3) Anchor
(4) Bias electrode
(5) Resonator
(51) Support beam
(52) Resonant beam
(53) Resonant beam
(54) Resonant beam
(41) Linked beam
(6) High frequency power supply
(7) Main voltage power supply
(8) Bias voltage power supply
(9) Board

Claims (9)

A resonator (5) whose both ends are supported on a substrate (9) and two electrodes (1) and (2) arranged opposite to the resonator (5) are provided, and one electrode (1 ) And the resonator (5) face each other to form one or more gaps, and the other electrode (2) and the resonator (5) face each other to make one or more gaps. And an alternating electrostatic force is generated between one or both of the electrodes (1), (2) and the resonator (5) by the input of a high frequency signal to vibrate the resonator (5), In a micro mechanical resonator that outputs a change in capacitance between one or both electrodes (1), (2) and a resonator (5) as a high frequency signal,
The resonator (5) includes a plurality of resonance beams arranged in parallel with each other on the substrate (9), and both ends of each resonance beam are supported on the substrate and adjacent resonances. A micromechanical resonator characterized in that beams are connected to each other at or near the antinodes of each vibration.   The micromechanical resonator according to claim 1, wherein the resonance beams of the plurality of resonance beams constituting the resonator (5) have different resonance frequencies.   The micromechanical resonator according to claim 2, wherein the plurality of resonance beams constituting the resonator (5) have different lengths.   4. The micromechanical resonator according to claim 3, wherein a ratio of a length of a longer resonance beam to a length of a shorter resonance beam among two adjacent resonance beams is less than 1.2. 5.   The ratio of the length of the longer resonant beam to the length of the shorter resonant beam of the two adjacent resonant beams is in the range of about 1.01 to about 1.02. Micro mechanical resonators.   Three or more gaps are formed between the resonator (5) and the electrodes (1) and (2), and the resonator (5) vibrates in a third-order or higher order resonance mode. The plurality of resonance beams constituting the resonator (5) are connected to each other at a position of an antinode of vibration in a higher-order resonance mode or a position in the vicinity thereof. Micromechanical resonator.   The two resonance beams adjacent to each other are connected to each other by a connection beam (41) having an elastic coefficient equal to or greater than the elastic coefficient of the resonance beam. Micromechanical resonator.   The electrostatic force is applied to the plurality of resonance beams constituting the resonator (5) in a direction perpendicular to a plane on which the resonance beams are arranged. The micromechanical resonator according to 1.   The electrostatic force is applied to a plurality of resonance beams constituting the resonator (5) in a direction parallel to a plane on which the resonance beams are arranged. The micromechanical resonator according to 1.

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