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WO2015194479A1 - Resonance-frequency adjustment module and mems sensor - Google Patents

Resonance-frequency adjustment module and mems sensor Download PDF

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Publication number
WO2015194479A1
WO2015194479A1 PCT/JP2015/067042 JP2015067042W WO2015194479A1 WO 2015194479 A1 WO2015194479 A1 WO 2015194479A1 JP 2015067042 W JP2015067042 W JP 2015067042W WO 2015194479 A1 WO2015194479 A1 WO 2015194479A1
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WO
WIPO (PCT)
Prior art keywords
movable electrode
resonance frequency
electrode
adjustment module
movable
Prior art date
Application number
PCT/JP2015/067042
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French (fr)
Japanese (ja)
Inventor
夕輝 植屋
威 岡見
潤弥 松岡
崇 溝田
辻　信昭
Original Assignee
株式会社村田製作所
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Filing date
Publication date
Application filed by 株式会社村田製作所 filed Critical 株式会社村田製作所
Publication of WO2015194479A1 publication Critical patent/WO2015194479A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B3/00—Devices comprising flexible or deformable elements, e.g. comprising elastic tongues or membranes
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C19/00—Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
    • G01C19/56—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
    • G01C19/5719—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces using planar vibrating masses driven in a translation vibration along an axis
    • G01C19/5769—Manufacturing; Mounting; Housings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/84—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by variation of applied mechanical force, e.g. of pressure

Definitions

  • the present invention relates to a resonance frequency adjustment module and a MEMS sensor.
  • MEMS Micro Electro Mechanical Systems
  • the above-described gyro sensor includes a vibration driving module supported on a substrate extending in the XY direction so as to vibrate in the X direction, a moving body connected to the vibration driving module, and the moving body in the Y direction.
  • a capacitance change detection module that is supported so as to be elastically movable and detects the amount of movement in the Y direction is provided.
  • the movable body and the movable electrode of the capacitance change detection module supported by the movable body are always reciprocated in the X direction, and the gyro sensor is perpendicular to the XY plane.
  • a Coriolis force acting on the movable electrode when it is rotated around an axis in the Z direction is detected as a movement of the movable electrode in the Y direction.
  • the movable electrode of the capacitance change detection module moves not only by the Coriolis force acting by the angular velocity (or rotational speed) of the gyro sensor but also by the acceleration in the Y direction of the gyro sensor.
  • the gyro sensor includes an elastic body that supports the movable body so as to be movable in the X direction. And the vibration of the X direction of a mobile body and an electrostatic capacitance change detection module is controlled by the resonant frequency decided by the spring constant and mass of this elastic body.
  • a resonance frequency adjustment module having an electrical spring structure has been proposed so that the resonance frequency can be controlled by adjusting the spring constant of the elastic body.
  • a resonance frequency adjustment module as shown in FIG. 5, a resonance frequency adjustment module 51 having a pair of opposed electrodes 52 and 53 capable of adjusting a voltage difference has been proposed (conventional example 1).
  • a resonance frequency adjustment module 61 in which a pair of comb-like electrodes 62 and 63 are arranged so as to fit each other has also been proposed (conventional example 2).
  • the resonance frequency adjustment module 51 of the conventional example 1 when used in a state where air is present, the air in the space between the electrodes 52 and 53 is compressed when the pair of electrodes 52 and 53 moves in the approaching direction. .
  • the resonance frequency adjustment module 51 of the conventional example 1 has a disadvantage that the air resistance (damping) due to the compression of air is large, the Q value (Quality Factor) is reduced and the amplitude is lowered, and the movement is increased.
  • the distance between the electrodes 52 and 53 becomes too close so-called pull-in.
  • the resonance frequency adjusting module 51 of the conventional example 1 it is necessary to increase the capacitance in order to increase the adjustment range of the spring constant.
  • the electrodes 52 and 53 should be increased or the number thereof should be increased. In this case, however, the reduction in the Q value due to the air resistance as described above becomes significant.
  • one comb-like electrode 63 is provided in a step shape so as to obtain a predetermined spring constant without affecting the movement of the movable electrode 62, and the Pull-in
  • This invention is made
  • the resonance frequency adjusting module constitutes a MEMS sensor for detecting an angular velocity, and is arranged so as to be movable, and extends along the moving direction of the movable electrode along the moving direction of the movable electrode.
  • a plurality of fixed electrodes arranged in a row, and an elastic body that supports the movable electrode so as to be movable in the moving direction.
  • the surface of the movable electrode facing the plurality of fixed electrodes has crests and troughs that are alternately arranged in the moving direction, and each of the plurality of fixed electrodes is a crest or a crest of the movable electrode. It arrange
  • the resonance frequency adjusting module according to the present invention has a crest and a trough where opposed surfaces of the movable electrode facing the fixed electrode are alternately arranged in the moving direction, and each fixed electrode is one crest or trough of the movable electrode. It arrange
  • the resonance frequency adjusting module since the opposed surfaces of the movable electrode and the fixed electrode are inclined with respect to the moving direction, the volume change between the opposed surfaces due to the movement of the movable electrode is small, and the relative air Resistance is small.
  • each fixed electrode faces one peak or valley of the movable electrode, so there is only one inflection point on the opposite surface of the fixed electrode, and the movable electrode is movable. Since the electrical characteristic between the electrodes is close to that of a parallel plate, the linearity of the electrostatic attractive force between the movable electrode and the fixed electrode with respect to the amount of movement of the movable electrode becomes relatively high.
  • the peak and the valley are formed at a substantially constant pitch, and the average pitch of the peak or the valley and the plurality of fixed electrodes are The difference from the average length in the moving direction is preferably 0.5 times or more and 1.2 times or less the average distance between the movable electrode and the plurality of fixed electrodes in the moving direction.
  • the difference between the average pitch of the peaks or valleys and the average length of the plurality of fixed electrodes in the moving direction is within the above range, the electrostatic capacitance between the movable electrode and the fixed electrode with respect to the moving amount of the movable electrode.
  • the linearity of the attractive force can be further improved.
  • the pitch between the peaks and valleys is substantially constant means that the variation in the distance between the apexes of the peaks and the distance between the bottom points of the valleys is within 10%.
  • each of the plurality of fixed electrodes may be opposed to the valley of the movable electrode. Since the fixed electrode faces the valley of the movable electrode in this way, the width at the central portion in the moving direction of the fixed electrode can be maximized, so that the fixed electrode can be fixed and wired easily.
  • an average inclination angle with respect to the moving direction of the facing surface of the movable electrode is 2 degrees or more and 12 degrees or less.
  • a relatively large stroke (amplitude) can be obtained by setting the average inclination angle with respect to the moving direction of the opposing surface of the movable electrode within the above range.
  • the MEMS sensor according to the present invention includes the resonance frequency adjusting module according to the present invention.
  • the MEMS sensor according to the present invention includes a resonant frequency adjustment module according to the present invention having high area efficiency, small air resistance, and high linearity, and thus is small and highly reliable.
  • the resonance frequency adjusting module and the MEMS sensor according to the present invention have high area efficiency and low air resistance.
  • FIG. 1 It is a schematic diagram which shows the resonant frequency adjustment module in 1st Embodiment of this invention. It is a schematic diagram which shows the resonance frequency adjustment module in 2nd Embodiment of this invention. It is a schematic diagram which shows the resonance frequency adjustment module in 3rd Embodiment of this invention. It is a schematic diagram which shows the resonance frequency adjustment module in 4th Embodiment of this invention. It is a schematic diagram which shows the resonant frequency adjustment module which concerns on the prior art example 1. FIG. It is a schematic diagram which shows the resonant frequency adjustment module which concerns on the prior art example 2. FIG.
  • a resonance frequency adjustment module 1 shown in FIG. 1 is a resonance frequency adjustment module that constitutes a MEMS sensor that detects angular velocity.
  • the resonance frequency adjusting module 1 is movably arranged, and a plurality of movable electrodes 2 extending in the movement direction (X direction), and a plurality of fixed electrodes 3 arranged along the movement direction X of the movable electrode 2.
  • an elastic body 4 that supports the movable electrode 2 so as to be movable in the movement direction X.
  • the opposed surface 20 of the movable electrode 2 to the fixed electrode 3 has crests 21 and troughs 22 arranged alternately in the movement direction X at a substantially constant pitch and inclination angle.
  • the opposing surface 20 is inclined in one direction with respect to the moving direction X (the normal line is inclined to the right side of the paper surface) and the second inclined surface is inclined to the other side (the normal line is inclined to the left side of the paper surface).
  • the inclined portions 24 are alternately provided.
  • the plurality of fixed electrodes 3 are arranged so as to face one trough portion 22 of the movable electrode 2.
  • the opposed surface 30 of the fixed electrode 3 to the movable electrode 2 includes a first inclined portion 31 that faces the first inclined portion 23 of the opposing surface 20 of the movable electrode 2 and a second inclined portion 32 that faces the second inclined portion 24.
  • the plurality of movable electrodes 2 are arranged in the Y direction orthogonal to the moving direction X, and the movable electrode 2 on the inner side in the Y direction includes opposing surfaces 20 having crests 21 and troughs 22 on both sides in the Y direction.
  • the peak portions 21 and valley portions 22 of the plurality of movable electrodes 2 arranged in the Y direction have the same center position in the movement direction X.
  • Each fixed electrode 3 is arranged in a row between the plurality of movable electrodes 2. That is, the fixed electrodes 3 are arranged in a plurality of rows in the Y direction. Each fixed electrode 3 has opposing surfaces 30 that face one trough portion 22 of the movable electrode 2 on both sides in the Y direction, and has a symmetrical shape in the moving direction X.
  • the movable electrode 2 is integrally held by the support member 5 and fixed to the moving body (not shown) of the MEMS sensor via the elastic body 4.
  • the fixed electrode 3 is fixedly fixed to a substrate (not shown) of the MEMS sensor.
  • FIG. 1 shows a weight 6 conceptually representing the mass of the moving part including the movable electrode 2 of the resonance frequency adjustment module 1.
  • electrostatic attractive force acts between the opposed surfaces 20 and 30 of the movable electrode 2 and the fixed electrode 3 by applying a potential difference between the movable electrode 2 and the fixed electrode 3.
  • the apparent spring constant of the resonance frequency adjusting module 1 can be adjusted.
  • the material of the movable electrode 2 and the fixed electrode 3 is not particularly limited, but for example, silicon can be used.
  • the average thickness of the movable electrode 2 and the fixed electrode 3 (the dimension in the depth direction in FIG. 1) is not particularly limited, but may be, for example, 20 ⁇ m or more and 50 ⁇ m or less. Further, the average thickness of the movable electrode 2 and the fixed electrode 3 may be further reduced as long as the manufacturing process allows.
  • the formation method of the movable electrode 2 and the fixed electrode 3 is not particularly limited, and for example, a method of selectively etching by forming a resist pattern on the surface of a plate-like material by a photolithography technique can be applied.
  • the lower limit of the average inclination angle of the opposed surface 20 of the movable electrode 2 and the opposed surface 30 of the fixed electrode 3 with respect to the moving direction X of the movable electrode 2 is preferably 2 degrees and more preferably 4 degrees.
  • the upper limit of the average inclination angle of the facing surface 20 of the movable electrode 2 and the facing surface 30 of the fixed electrode 3 with respect to the moving direction X of the movable electrode 2 is preferably 12 degrees, and more preferably 8 degrees.
  • the average inclination angle of the opposing surface 20 of the movable electrode 2 and the opposing surface 30 of the fixed electrode 3 with respect to the moving direction X of the movable electrode 2 is less than the lower limit, the distance between the opposing surfaces 20 and 30 with respect to the moving amount of the movable electrode. There is a possibility that the area efficiency of the resonance frequency adjustment module 1 is lowered. Further, when the average inclination angle of the opposed surface 20 of the movable electrode 2 and the opposed surface 30 of the fixed electrode 3 with respect to the moving direction X of the movable electrode 2 exceeds the upper limit, the movable range of the movable electrode 2 is narrowed, and the resonance frequency is reduced. There is a possibility that the amplitude of the adjustment module 1 becomes insufficient.
  • each average pitch (average interval of peak portions 21 and average interval of valley portions 22) of peak portion 21 and valley portion 22 the maximum movement amount in use from the reference position of movable electrode 2 is 1.5. Double is preferable, and double is more preferable.
  • the upper limit of the average pitch of the peak portion 21 and the valley portion 22 is preferably four times the maximum movement amount in use from the reference position of the movable electrode 2, and more preferably three times. When the average pitch of each of the peak portion 21 and the valley portion 22 is less than the lower limit, the rate of change of the interval between the opposing surfaces 20 and 30 increases, and the distance between the movable electrode 2 and the fixed electrode 3 with respect to the movement amount of the movable electrode 2 is increased.
  • the lower limit of the average distance between the facing surface 20 of the movable electrode 2 and the facing surface 30 of the fixed electrode 3 is preferably 0.5 ⁇ m and more preferably 1 ⁇ m.
  • the upper limit of the average distance between the facing surface 20 of the movable electrode 2 and the facing surface 30 of the fixed electrode 3 is preferably 3 ⁇ m, and more preferably 2.5 ⁇ m.
  • the first inclined portion 23 of the facing surface 20 of the movable electrode 2 and the first surface of the facing surface 30 of the fixed electrode 3 increases, and the movable electrode 2 moves. There is a possibility that the linearity of the electrostatic attractive force with respect to the quantity becomes insufficient.
  • the “average distance” between the facing surface 20 and the facing surface 30 means the average distance in the bisector direction between the normal line of the facing surface 20 and the normal line of the facing surface 30.
  • the lower limit of the difference between the average pitch of the crests 21 or troughs 22 of the opposing surface 20 of the movable electrode 2 and the average length of the plurality of fixed electrodes 3 in the movement direction X is the movable electrode 2 and the plurality of fixed in the movement direction X. 0.5 times the average distance from the electrode 3 is preferable, and 0.6 times is more preferable.
  • the upper limit of the difference between the average pitch of the crests 21 or troughs 22 of the opposed surface 20 of the movable electrode 2 and the average length in the movement direction X of the plurality of fixed electrodes 3 1.2 times the average distance from the fixed electrode 3 is preferably 1.0 times.
  • the movable electrode 2 When the difference between the average pitch of the crests 21 or troughs 22 of the opposed surface 20 of the movable electrode 2 and the average length in the moving direction X of the plurality of fixed electrodes 3 is less than the lower limit, the movable electrode 2 is moved to the reference position (moving The linearity of the electrostatic attractive force with respect to the movement amount of the movable electrode 2 becomes insufficient due to the influence of the peak portion 21 or the valley portion 22 of the facing surface 20 of the movable electrode 2 that does not face the fixed electrode 3 in a state of zero amount). There is a fear.
  • the resonance frequency adjustment module 1 has crests 21 and troughs 22 in which the opposed surfaces 20 of the movable electrode 2 are alternately arranged in the movement direction X, and each fixed electrode 3 is one trough of the movable electrode 2. Since the movable electrode 2 is disposed so as to face the portion 22, one of the distance between the first inclined portions 23 and 31 and the distance between the second inclined portions 24 and 32 increases and the other decreases due to the movement of the movable electrode 2. . Thereby, the electrostatic attractive force acting between the movable electrode 2 and the fixed electrode 3 acts in a direction in which the movable electrode 2 is further moved in the movement direction X, and the force increases as the movement amount increases.
  • the resonance frequency adjusting module 1 can adjust the resonance frequency of the weight 6 including the movable electrode 2 by partially canceling the restoring force of the elastic body 4 and changing the apparent spring constant. Further, the resonance frequency adjusting module 1 has a higher area efficiency than a conventional comb-shaped one.
  • the resonance frequency adjusting module 1 since the opposing surfaces 20, 30 of the movable electrode 2 and the fixed electrode 3 are inclined with respect to the movement direction X, the volume change between the opposing surfaces 20, 30 due to the movement of the movable electrode. Is small and air resistance is small.
  • each fixed electrode 3 faces one valley 22 of the movable electrode 2, so there is only one inflection point on the facing surface 30 of the fixed electrode 3. Therefore, the linearity of the electrostatic attractive force between the movable electrode 2 and the fixed electrode 3 with respect to the amount of movement of the movable electrode 2 is relatively high.
  • the fixed electrode 3 faces the trough portion 22 of the movable electrode 2, the width at the central portion in the moving direction X of the fixed electrode 3 can be maximized, so that the fixed electrode 3 can be easily fixed and wired by, for example, a via hole. It becomes.
  • the resonance frequency adjusting module 1 is used for a gyro sensor (MEMS sensor) as described above.
  • This gyro sensor is, for example, a movable body that is supported on a substrate extending in the XY direction so as to be movable in the X direction, and that the movable electrode for detection is movable in the Y direction.
  • the two electrostatic capacity change detection modules supported by the sensor and a vibration drive module that reciprocates the moving body in the X direction can be used.
  • the fixed electrode 3 is fixed to the substrate, and the movable electrode 2 is fixed to the moving body.
  • the apparent spring constant can be adjusted to a desired value by adjusting the potential difference between the movable electrode 2 and the fixed electrode 3. For this reason, the resonant frequency of a mobile body and an electrostatic capacitance change detection module can be controlled easily and reliably.
  • a resonance frequency adjustment module 1a shown in FIG. 2 is a resonance frequency adjustment module that constitutes a MEMS sensor that detects angular velocity.
  • the resonance frequency adjusting module 1a is movably arranged, and a plurality of movable electrodes 2a extending in the movement direction (X direction), and a plurality of fixed electrodes 3a arranged along the movement direction X of the movable electrode 2a.
  • an elastic body 4 that supports the movable electrode 2a so as to be movable in the movement direction X.
  • the opposed surface 20 of the movable electrode 2a to the fixed electrode 3a has crests 21 and troughs 22 arranged alternately in the movement direction X at a substantially constant pitch and inclination angle.
  • the plurality of fixed electrodes 3a are disposed so as to face the crests 21 of the movable electrode 2, respectively.
  • the opposed surface 30 of the fixed electrode 3a to the movable electrode 2a includes a first inclined portion 31 that faces the first inclined portion 23 of the opposed surface 20 of the movable electrode 2a, and a second inclined surface that is inclined opposite to the first inclined portion 23. And a second inclined portion 32 facing the inclined portion 24.
  • the width of the fixed electrode 3a in the Y direction perpendicular to the moving direction X is narrowed toward the center of the moving direction X.
  • the movable electrode 2a is integrally held by the support member 5 and fixed to a moving body (not shown) of the MEMS sensor via the elastic body 4.
  • the fixed electrode 3a is fixed on a substrate (not shown) of the MEMS sensor.
  • FIG. 2 shows a weight 6 conceptually representing the mass of the moving part including the movable electrode 2a of the resonance frequency adjusting module 1a.
  • the resonance frequency adjusting module 1a gives a potential difference between the movable electrode 2a and the fixed electrode 3a, an electrostatic attractive force (Coulomb force) acts between the opposing surfaces 20 and 30 of the movable electrode 2a and the fixed electrode 3a.
  • an electrostatic attractive force acts between the opposing surfaces 20 and 30 of the movable electrode 2a and the fixed electrode 3a.
  • the material and manufacturing method of the movable electrode 2a and the fixed electrode 3a in the resonance frequency adjustment module 1a shown in FIG. 2 are the same as the material and manufacturing method of the movable electrode 2 and the fixed electrode 3 in the resonance frequency adjustment module 1 shown in FIG. .
  • a resonance frequency adjustment module 1b shown in FIG. 3 is a resonance frequency adjustment module constituting a MEMS sensor that detects angular velocity.
  • the resonance frequency adjusting module 1b is movably arranged, and a plurality of movable electrodes 2b extending in the movement direction (X direction), and a plurality of fixed electrodes 3 arranged along the movement direction X of the movable electrode 2b. , 3a and an elastic body 4 that supports the movable electrode 2b so as to be movable in the movement direction X.
  • the facing surface 20 of the movable electrode 2b facing the fixed electrodes 3 and 3a has crests 21 and troughs 22 that are alternately arranged in the movement direction X with a substantially constant pitch and inclination angle.
  • the movable electrode 2b has a planar shape that is bent zigzag with a constant width by arranging the peak portion 21 and the valley portion 22 back to back in the Y direction orthogonal to the movement direction X.
  • these movable electrodes 2b are alternately arranged so that the adjacent movable electrodes 2b face the peak portion 21 and the valley portion 22.
  • the resonance frequency adjusting module 1b shown in FIG. 3 includes a plurality of first fixed electrodes 3 arranged in a row so as to face the valleys 22 of the facing surface 20 of the movable electrode 2b, and the fixed electrodes 3 of the movable electrode 2b.
  • the first fixed electrode 3 of the resonance frequency adjustment module 1b shown in FIG. 3 has the same shape as the fixed electrode 3 in the resonance frequency adjustment module 1 shown in FIG.
  • the second fixed electrode 3a of the resonance frequency adjustment module 1b shown in FIG. 3 has the same shape as the fixed electrode 3a in the resonance frequency adjustment module 1a shown in FIG.
  • the movable electrode 2b is integrally held by the support member 5, and is fixed to a moving body (not shown) of the MEMS sensor via the elastic body 4.
  • the fixed electrodes 3 and 3a are fixedly fixed to a substrate (not shown) of the MEMS sensor.
  • FIG. 3 shows a weight 6 conceptually representing the mass of the moving part including the movable electrode 2b of the resonance frequency adjustment module 1b.
  • the resonance frequency adjusting module 1b gives an electrostatic attraction (Coulomb force) between the opposed surfaces 20 and 30 of the movable electrode 2b and the fixed electrodes 3 and 3a by applying a potential difference between the movable electrode 2b and the fixed electrodes 3 and 3a. Therefore, the apparent spring constant of the resonance frequency adjusting module 1b can be adjusted by adjusting the potential difference.
  • the material and manufacturing method of the movable electrode 2b in the resonance frequency adjusting module 1b shown in FIG. 3 are the same as the material and manufacturing method of the movable electrode 2 in the resonance frequency adjusting module 1 shown in FIG.
  • a resonance frequency adjustment module 1c shown in FIG. 4 is a resonance frequency adjustment module constituting a MEMS sensor that detects angular velocity.
  • the resonance frequency adjustment module 1c is movably arranged, and a plurality of movable electrodes 2b extending in the movement direction (X direction), and a plurality of fixed electrodes 3 arranged along the movement direction X of the movable electrode 2b.
  • an elastic body 4 that supports the movable electrode 2b so as to be movable in the movement direction X.
  • the movable electrode 2b in the resonance frequency adjustment module 1c shown in FIG. 4 has the same shape and arrangement as the movable electrode 2b in the resonance frequency adjustment module 1b shown in FIG. Further, the fixed electrode 3 in the resonance frequency adjustment module 1c shown in FIG. 4 has the same shape as the fixed electrode 3 in the resonance frequency adjustment module 1 shown in FIG.
  • the fixed electrodes 3 are arranged in a row between the plurality of movable electrodes 2b so that all of the fixed electrodes 3 face the recesses 22 of the movable electrode 2b. For this reason, the arrangement of the fixed electrodes 3 in the movement direction X is shifted by a half pitch every other row in accordance with the shape of the movable electrode 2b.
  • the movable electrode 2b is integrally held by the support member 5, and is fixed to the moving body (not shown) of the MEMS sensor via the elastic body 4.
  • the fixed electrode 3 is fixedly fixed to a substrate (not shown) of the MEMS sensor.
  • FIG. 4 shows a weight 6 conceptually representing the mass of the moving part including the movable electrode 2b of the resonance frequency adjusting module 1c.
  • the resonance frequency adjusting module 1c gives a potential difference between the movable electrode 2b and the fixed electrode 3, an electrostatic attractive force (Coulomb force) acts between the opposing surfaces 20 and 30 of the movable electrode 2b and the fixed electrode 3.
  • an electrostatic attractive force acts between the opposing surfaces 20 and 30 of the movable electrode 2b and the fixed electrode 3.
  • the number of movable electrode and fixed electrode rows and the number of fixed electrode rows can be arbitrarily changed.
  • fixed electrodes may be arranged on both sides of the movable electrode.
  • the facing surfaces of the movable electrode and the fixed electrode are not limited to flat surfaces, and may be curved surfaces.
  • Model No. of movable electrode and fixed electrode of resonance frequency adjustment module having the shape of the first embodiment. 1 and no. 2 was modeled on a simulator, and the generated electrostatic attraction was confirmed by simulation.
  • Model No. 1 and no. 2 had the shape shown in Table 1 below. Each model was modeled as having three movable electrodes and a total of six fixed electrodes arranged in two rows of three each between the three movable electrodes.
  • model no. 1 is that the angle with respect to the moving direction X of the opposing surfaces of the movable electrode and the fixed electrode is constant at 6.04 degrees, and the interval between the opposing surfaces of the movable electrode and the fixed electrode (the above-mentioned “average interval”) is constant at 2.1 ⁇ m.
  • the pitch of the peaks (and valleys) was constant at 40 ⁇ m, and the length of the fixed electrode in the moving direction X was constant at 24 ⁇ m.
  • the average distance in the moving direction X between the opposing surfaces of the movable electrode and the fixed electrode, which is derived from the inclination angle of the opposing surfaces and the interval between the opposing surfaces, is 20 ⁇ m.
  • the difference between the pitch of one peak and the length of the fixed electrode in the moving direction X is 0.8 times the average distance between the movable electrode and the plurality of fixed electrodes in the moving direction X.
  • Model No. 2 Model No. 2
  • the angle of the opposing surfaces of the movable electrode and the fixed electrode with respect to the moving direction X is constant at 4.60 degrees
  • the interval between the opposing surfaces of the movable electrode and the fixed electrode is constant at 1.6 ⁇ m
  • the peaks (and valleys) Part was made constant at 40 ⁇ m
  • the length of the fixed electrode in the moving direction X was made constant at 24 ⁇ m.
  • the average distance in the moving direction X between the opposed surfaces of the movable electrode and the fixed electrode derived from the inclination angle of the opposed surface and the interval between the opposed surfaces is 20 ⁇ m.
  • Model No. The difference between the pitch of the two peaks and the length of the fixed electrode in the moving direction X is 0.8 times the average distance between the movable electrode and the plurality of fixed electrodes in the moving direction X.
  • Model No. 2 has a crest and a trough where the surface of the movable electrode facing the fixed electrode is alternately arranged in the moving direction, and a plurality of fixed electrodes are arranged to face the crest of the movable electrode. 1 and no. 2 confirms that the change in the ratio of the electrostatic attractive force to this moving amount (apparent spring constant) within the range up to 12 ⁇ m is high linearity within ⁇ 10%. It was done.
  • the resonance frequency adjustment module according to the present invention can be suitably used for a MEMS sensor that detects angular velocity.
  • 1, 1a, 1b, 1c Resonance frequency adjustment module, 2, 2a, 2b movable electrode, 20 facing surface, 21 mountain part, 22 valley part, 23 first inclined part, 24 second inclined part, 3, 3a fixed electrode, 30 opposing surface, 31 1st inclined part, 32 2nd inclined part, 4 elastic body, 5 support member, 6 weight, X movement direction.

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Abstract

This resonance-frequency adjustment module (1), which constitutes a MEMS sensor that detects angular velocity, comprises movable electrodes (2), a plurality of fixed electrodes (3), and an elastic body (4). The movable electrodes (2), which are provided so as to be able to move, extend in a given movement direction (X). The fixed electrodes (3) are arrayed in the movement direction (X) of the movable electrodes (2). The elastic body (4) supports the movable electrodes (2) such that same can move in the aforementioned movement direction (X). The surfaces (20) of the movable electrodes (2) that face the fixed electrodes (3) have convex sections (21) and concave sections (22) that are laid out in an alternating manner in the movement direction (X), and each fixed electrode (3) is provided so as to face a single convex section (21) or concave section (22) of each adjacent movable electrode (2).

Description

共振周波数調整モジュール及びＭＥＭＳセンサResonance frequency adjustment module and MEMS sensor
　本発明は、共振周波数調整モジュール及びＭＥＭＳセンサに関する。 The present invention relates to a resonance frequency adjustment module and a MEMS sensor.
　近年、ＭＥＭＳ（Ｍｉｃｒｏ　Ｅｌｅｃｔｒｏ　Ｍｅｃｈａｎｉｃａｌ　Ｓｙｓｔｅｍｓ）と呼ばれる半導体製造技術を利用して形成した微細な機械要素を有する装置が開発されており、被測定体の角速度を検出するジャイロセンサや加速度センサとして実現されている。 In recent years, devices having fine mechanical elements formed using a semiconductor manufacturing technology called MEMS (Micro Electro Mechanical Systems) have been developed and realized as gyro sensors and acceleration sensors for detecting the angular velocity of a measured object. Yes.
　例えば、上述のジャイロセンサは、Ｘ－Ｙ方向に延在する基板上にＸ方向に振動可能に支持される振動駆動モジュール、この振動駆動モジュールに接続される移動体、この移動体にＹ方向に弾性移動可能に支持されＹ方向の移動量を検出する静電容量変化検出モジュール等を備えている。 For example, the above-described gyro sensor includes a vibration driving module supported on a substrate extending in the XY direction so as to vibrate in the X direction, a moving body connected to the vibration driving module, and the moving body in the Y direction. A capacitance change detection module that is supported so as to be elastically movable and detects the amount of movement in the Y direction is provided.
　このようなジャイロセンサは、振動駆動モジュールによって移動体及び移動体に支持されている静電容量変化検出モジュールの可動電極をＸ方向に常時往復移動させておき、ジャイロセンサがＸ－Ｙ平面に垂直なＺ方向の軸を中心に回転したときに可動電極に作用するコリオリ力を可動電極のＹ方向の移動として検出する。静電容量変化検出モジュールの可動電極は、ジャイロセンサの角速度（又は回転速度）により作用するコリオリ力だけでなく、ジャイロセンサのＹ方向の加速度によっても移動する。そこで、２つの静電容量変化検出モジュールの可動電極の移動の差分をとることでジャイロセンサに加えられたＹ方向の加速度を相殺し、ジャイロセンサのＸ－Ｙ平面上の向きの変化のみを検出する（例えば特開２０１３－９６９５２号公報参照）。 In such a gyro sensor, the movable body and the movable electrode of the capacitance change detection module supported by the movable body are always reciprocated in the X direction, and the gyro sensor is perpendicular to the XY plane. A Coriolis force acting on the movable electrode when it is rotated around an axis in the Z direction is detected as a movement of the movable electrode in the Y direction. The movable electrode of the capacitance change detection module moves not only by the Coriolis force acting by the angular velocity (or rotational speed) of the gyro sensor but also by the acceleration in the Y direction of the gyro sensor. Therefore, by taking the difference in the movement of the movable electrodes of the two capacitance change detection modules, the acceleration in the Y direction applied to the gyro sensor is canceled, and only the change in the orientation of the gyro sensor on the XY plane is detected. (For example, refer to JP2013-96952A).
　また、ジャイロセンサは、移動体をＸ方向に移動可能に支持する弾性体を備えている。そして、移動体及び静電容量変化検出モジュールのＸ方向の振動は、この弾性体のばね定数と質量とによって決まる共振周波数によって規制される。このため、弾性体のばね定数を調整し、共振周波数をコントロールできるように、電気的ばね構造を有する共振周波数調整モジュールが提案されている。このような共振周波数調整モジュールとしては、図５に示すように、電圧差を調整可能な対向する一対の電極５２，５３を有する共振周波数調整モジュール５１が提案されている（従来例１）。また、図６に示すように、一対の櫛歯状の電極６２，６３が互いに嵌り込むよう配設された共振周波数調整モジュール６１も提案されている（従来例２）。 Also, the gyro sensor includes an elastic body that supports the movable body so as to be movable in the X direction. And the vibration of the X direction of a mobile body and an electrostatic capacitance change detection module is controlled by the resonant frequency decided by the spring constant and mass of this elastic body. For this reason, a resonance frequency adjustment module having an electrical spring structure has been proposed so that the resonance frequency can be controlled by adjusting the spring constant of the elastic body. As such a resonance frequency adjustment module, as shown in FIG. 5, a resonance frequency adjustment module 51 having a pair of opposed electrodes 52 and 53 capable of adjusting a voltage difference has been proposed (conventional example 1). In addition, as shown in FIG. 6, a resonance frequency adjustment module 61 in which a pair of comb- like electrodes 62 and 63 are arranged so as to fit each other has also been proposed (conventional example 2).
特開２０１３－９６９５２号公報JP 2013-96952 A
　しかし、従来例１の共振周波数調整モジュール５１を空気が存在する状態で使用すると、一対の電極５２，５３が近接する方向に移動した際に、電極５２，５３間の空間の空気が圧縮される。このため、従来例１の共振周波数調整モジュール５１は、空気の圧縮による空気抵抗（ｄａｍｐｉｎｇ）が大きく、Ｑ値（Ｑｕａｌｉｔｙ　Ｆａｃｔｏｒ）が減少して振幅が低下するという不都合があると共に、移動が大きくなると電極５２，５３同士の距離が近くなり過ぎいわゆるＰｕｌｌ－ｉｎするという不都合がある。特に、従来例１の共振周波数調整モジュール５１において、ばね定数の調整範囲を大きくするには静電容量を大きくする必要があり、このためには電極５２，５３を大きくする又は数を増やすことを要するが、この場合、上述のような空気抵抗によるＱ値の減少が顕著となる。 However, when the resonance frequency adjusting module 51 of the conventional example 1 is used in a state where air is present, the air in the space between the electrodes 52 and 53 is compressed when the pair of electrodes 52 and 53 moves in the approaching direction. . For this reason, the resonance frequency adjustment module 51 of the conventional example 1 has a disadvantage that the air resistance (damping) due to the compression of air is large, the Q value (Quality Factor) is reduced and the amplitude is lowered, and the movement is increased. There is an inconvenience that the distance between the electrodes 52 and 53 becomes too close so-called pull-in. In particular, in the resonance frequency adjusting module 51 of the conventional example 1, it is necessary to increase the capacitance in order to increase the adjustment range of the spring constant. For this purpose, the electrodes 52 and 53 should be increased or the number thereof should be increased. In this case, however, the reduction in the Q value due to the air resistance as described above becomes significant.
　また、従来例２の共振周波数調整モジュール６１では、可動電極６２の移動に影響せず所定のばね定数を得るべく、一方の櫛歯状の電極６３が階段状に設けられており、Ｐｕｌｌ－ｉｎの不都合が生じ難いが、ばね定数及び静電容量を大きくするためには、電極６２，６３を大きくすること、又は電極６２，６３の個数を増やすことを要し、これにより共振周波数調整モジュール６１が大きくなってしまい、面積効率が悪い。 Further, in the resonance frequency adjusting module 61 of the conventional example 2, one comb-like electrode 63 is provided in a step shape so as to obtain a predetermined spring constant without affecting the movement of the movable electrode 62, and the Pull-in However, in order to increase the spring constant and the capacitance, it is necessary to increase the number of the electrodes 62 and 63 or increase the number of the electrodes 62 and 63, thereby the resonance frequency adjusting module 61. Becomes large and area efficiency is poor.
　本発明は、上述のような事情に基づいてなされたものであり、面積効率が高く空気抵抗が小さい共振周波数調整モジュール及びＭＥＭＳセンサを提供することを課題とする。 This invention is made | formed based on the above situations, and makes it a subject to provide the resonance frequency adjustment module and MEMS sensor with a high area efficiency and small air resistance.
　本発明に基づく共振周波数調整モジュールは、角速度を検出するＭＥＭＳセンサを構成するものであって、移動可能に配設され、移動方向に延在する可動電極と、上記可動電極の上記移動方向に沿って配列する複数の固定電極と、上記可動電極を上記移動方向に移動可能に支持する弾性体とを備える。上記可動電極の上記複数の固定電極との対向面は、上記移動方向に交互に配列する山部及び谷部を有し、上記複数の固定電極の各々は、上記可動電極の１つの山部又は谷部に対向するよう配設される。 The resonance frequency adjusting module according to the present invention constitutes a MEMS sensor for detecting an angular velocity, and is arranged so as to be movable, and extends along the moving direction of the movable electrode along the moving direction of the movable electrode. A plurality of fixed electrodes arranged in a row, and an elastic body that supports the movable electrode so as to be movable in the moving direction. The surface of the movable electrode facing the plurality of fixed electrodes has crests and troughs that are alternately arranged in the moving direction, and each of the plurality of fixed electrodes is a crest or a crest of the movable electrode. It arrange | positions so that a trough part may be opposed.
　上記本発明に基づく共振周波数調整モジュールは、可動電極の固定電極との対向面が移動方向に交互に配列する山部及び谷部を有し、各固定電極が可動電極の１つの山部又は谷部に対向するよう配設される。つまり、固定電極は、可動電極の対向面のうち、移動方向に対して異なる方向に傾斜する２つの領域に対向するため、可動電極の移動により、一方の領域における対向面の間隔が増大し、他方の領域における対向面の間隔が減少する。これにより、可動電極と固定電極との間に作用する静電引力は、可動電極を移動方向にさらに移動させる向きに作用し、かつ移動量が大きいほどその力が大きくなる。従って、上記本発明に基づく共振周波数調整モジュールは、弾性体の復元力を部分的に相殺して可動電極の共振周波数を調整することができると共に、従来の櫛歯状のものと比べて面積効率が高い。 The resonance frequency adjusting module according to the present invention has a crest and a trough where opposed surfaces of the movable electrode facing the fixed electrode are alternately arranged in the moving direction, and each fixed electrode is one crest or trough of the movable electrode. It arrange | positions so that a part may be opposed. That is, since the fixed electrode faces two regions inclined in different directions with respect to the moving direction among the opposed surfaces of the movable electrode, the movement of the movable electrode increases the interval between the opposed surfaces in one region, The distance between the opposing surfaces in the other region is reduced. Thereby, the electrostatic attractive force acting between the movable electrode and the fixed electrode acts in a direction in which the movable electrode is further moved in the moving direction, and the force increases as the moving amount increases. Therefore, the resonance frequency adjustment module according to the present invention can partially cancel the restoring force of the elastic body to adjust the resonance frequency of the movable electrode, and has an area efficiency higher than that of a conventional comb-shaped one. Is expensive.
　また、上記本発明に基づく共振周波数調整モジュールは、可動電極及び固定電極の対向面が移動方向に対して傾斜しているので、可動電極の移動による対向面間の体積変化が小さく、比較的空気抵抗が小さい。 In the resonance frequency adjusting module according to the present invention, since the opposed surfaces of the movable electrode and the fixed electrode are inclined with respect to the moving direction, the volume change between the opposed surfaces due to the movement of the movable electrode is small, and the relative air Resistance is small.
　また、上記本発明に基づく共振周波数調整モジュールは、各固定電極が、可動電極の１つの山部又は谷部に対向するので、固定電極の対向面の変曲点が一カ所だけであり、可動電極との間の電気的特性が平行平板に近いものとなるので、可動電極の移動量に対する可動電極及び固定電極間の静電引力の線形性が比較的高くなる。 Further, in the resonance frequency adjustment module according to the present invention, each fixed electrode faces one peak or valley of the movable electrode, so there is only one inflection point on the opposite surface of the fixed electrode, and the movable electrode is movable. Since the electrical characteristic between the electrodes is close to that of a parallel plate, the linearity of the electrostatic attractive force between the movable electrode and the fixed electrode with respect to the amount of movement of the movable electrode becomes relatively high.
　上記本発明に基づく共振周波数調整モジュールにあっては、上記山部及び上記谷部が略一定のピッチで形成されているとともに、上記山部又は上記谷部の平均ピッチと上記複数の固定電極の上記移動方向の平均長さとの差が、上記移動方向における上記可動電極と上記複数の固定電極との間の平均距離の０．５倍以上１．２倍以下であることが好ましい。このように、山部又は谷部の平均ピッチと複数の固定電極の移動方向の平均長さとの差が上記範囲内であることによって、可動電極の移動量に対する可動電極及び固定電極間の静電引力の線形性をより向上できる。なお、「山部及び谷部が略一定のピッチ」とは、山部の頂点間距離及び谷部の谷底点間距離のばらつきが１０％以内であることをいう。 In the resonance frequency adjusting module according to the present invention, the peak and the valley are formed at a substantially constant pitch, and the average pitch of the peak or the valley and the plurality of fixed electrodes are The difference from the average length in the moving direction is preferably 0.5 times or more and 1.2 times or less the average distance between the movable electrode and the plurality of fixed electrodes in the moving direction. As described above, since the difference between the average pitch of the peaks or valleys and the average length of the plurality of fixed electrodes in the moving direction is within the above range, the electrostatic capacitance between the movable electrode and the fixed electrode with respect to the moving amount of the movable electrode. The linearity of the attractive force can be further improved. Note that “the pitch between the peaks and valleys is substantially constant” means that the variation in the distance between the apexes of the peaks and the distance between the bottom points of the valleys is within 10%.
　上記本発明に基づく共振周波数調整モジュールにあっては、上記複数の固定電極の各々が、上記可動電極の上記谷部に対向するとよい。このように固定電極が可動電極の谷部に対向することにより、固定電極の移動方向の中央部での幅を極大化できるので、固定電極の固定及び配線が容易となる。 In the resonance frequency adjustment module according to the present invention, each of the plurality of fixed electrodes may be opposed to the valley of the movable electrode. Since the fixed electrode faces the valley of the movable electrode in this way, the width at the central portion in the moving direction of the fixed electrode can be maximized, so that the fixed electrode can be fixed and wired easily.
　上記本発明に基づく共振周波数調整モジュールにあっては、上記可動電極の上記対向面の上記移動方向に対する平均傾斜角が、２度以上１２度以下であることが好ましい。このように、可動電極の対向面の移動方向に対する平均傾斜角を上記範囲内とすることにより、比較的大きなストローク（振幅）が得られる。 In the resonance frequency adjusting module according to the present invention, it is preferable that an average inclination angle with respect to the moving direction of the facing surface of the movable electrode is 2 degrees or more and 12 degrees or less. Thus, a relatively large stroke (amplitude) can be obtained by setting the average inclination angle with respect to the moving direction of the opposing surface of the movable electrode within the above range.
　本発明に基づくＭＥＭＳセンサは、上記本発明に基づく共振周波数調整モジュールを備える。 The MEMS sensor according to the present invention includes the resonance frequency adjusting module according to the present invention.
　上記本発明に基づくＭＥＭＳセンサは、高い面積効率と、小さい空気抵抗と、高い線形性とを備える上記本発明に基づく共振周波数調整モジュールを備えるため、小型で信頼性が高い。 The MEMS sensor according to the present invention includes a resonant frequency adjustment module according to the present invention having high area efficiency, small air resistance, and high linearity, and thus is small and highly reliable.
　以上のように、上記本発明に基づく共振周波数調整モジュール及びＭＥＭＳセンサは、面積効率が高く空気抵抗が小さい。 As described above, the resonance frequency adjusting module and the MEMS sensor according to the present invention have high area efficiency and low air resistance.
本発明の第１実施形態における共振周波数調整モジュールを示す模式図である。It is a schematic diagram which shows the resonant frequency adjustment module in 1st Embodiment of this invention. 本発明の第２実施形態における共振周波数調整モジュールを示す模式図である。It is a schematic diagram which shows the resonance frequency adjustment module in 2nd Embodiment of this invention. 本発明の第３実施形態における共振周波数調整モジュールを示す模式図である。It is a schematic diagram which shows the resonance frequency adjustment module in 3rd Embodiment of this invention. 本発明の第４実施形態における共振周波数調整モジュールを示す模式図である。It is a schematic diagram which shows the resonance frequency adjustment module in 4th Embodiment of this invention. 従来例１に係る共振周波数調整モジュールを示す模式図である。It is a schematic diagram which shows the resonant frequency adjustment module which concerns on the prior art example 1. FIG. 従来例２に係る共振周波数調整モジュールを示す模式図である。It is a schematic diagram which shows the resonant frequency adjustment module which concerns on the prior art example 2. FIG.
　以下、適宜図面を参照しつつ、本発明の実施形態について詳説する。
　［第１実施形態］
　図１に示す共振周波数調整モジュール１は、角速度を検出するＭＥＭＳセンサを構成する共振周波数調整モジュールである。当該共振周波数調整モジュール１は、移動可能に配設され、移動方向（Ｘ方向）に延在する複数の可動電極２と、この可動電極２の移動方向Ｘに沿って配列する複数の固定電極３と、可動電極２を移動方向Ｘに移動可能に支持する弾性体４とを主に備える。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
[First Embodiment]
A resonance frequency adjustment module 1 shown in FIG. 1 is a resonance frequency adjustment module that constitutes a MEMS sensor that detects angular velocity. The resonance frequency adjusting module 1 is movably arranged, and a plurality of movable electrodes 2 extending in the movement direction (X direction), and a plurality of fixed electrodes 3 arranged along the movement direction X of the movable electrode 2. And an elastic body 4 that supports the movable electrode 2 so as to be movable in the movement direction X.
　可動電極２の固定電極３との対向面２０は、略一定のピッチ及び傾斜角で移動方向Ｘに交互に配列する山部２１及び谷部２２を有する。換言すると、対向面２０は、移動方向Ｘに対して一方側に傾斜（法線が紙面右側に傾斜）する第１傾斜部２３と他方側に傾斜（法線が紙面左側に傾斜）する第２傾斜部２４とを交互に有する。複数の固定電極３は、それぞれ可動電極２の１つの谷部２２に対向するよう配設される。固定電極３の可動電極２との対向面３０は、可動電極２の対向面２０の第１傾斜部２３に対向する第１傾斜部３１と第２傾斜部２４に対向する第２傾斜部３２とを有する。 The opposed surface 20 of the movable electrode 2 to the fixed electrode 3 has crests 21 and troughs 22 arranged alternately in the movement direction X at a substantially constant pitch and inclination angle. In other words, the opposing surface 20 is inclined in one direction with respect to the moving direction X (the normal line is inclined to the right side of the paper surface) and the second inclined surface is inclined to the other side (the normal line is inclined to the left side of the paper surface). The inclined portions 24 are alternately provided. The plurality of fixed electrodes 3 are arranged so as to face one trough portion 22 of the movable electrode 2. The opposed surface 30 of the fixed electrode 3 to the movable electrode 2 includes a first inclined portion 31 that faces the first inclined portion 23 of the opposing surface 20 of the movable electrode 2 and a second inclined portion 32 that faces the second inclined portion 24. Have
　複数の可動電極２は、移動方向Ｘに直交するＹ方向に配列されており、Ｙ方向内側の可動電極２は、山部２１及び谷部２２を有する対向面２０をＹ方向両側に備える。Ｙ方向に並ぶこれら複数の可動電極２の山部２１及び谷部２２は、移動方向Ｘの中心位置が一致している。 The plurality of movable electrodes 2 are arranged in the Y direction orthogonal to the moving direction X, and the movable electrode 2 on the inner side in the Y direction includes opposing surfaces 20 having crests 21 and troughs 22 on both sides in the Y direction. The peak portions 21 and valley portions 22 of the plurality of movable electrodes 2 arranged in the Y direction have the same center position in the movement direction X.
　各固定電極３は、複数の可動電極２の間にそれぞれ一列に配列されている。つまり、固定電極３は、Ｙ方向に複数列配設されている。また、各固定電極３は、Ｙ方向両側に可動電極２の１つの谷部２２に対向する対向面３０を有し、移動方向Ｘに対称な形状を有している。 Each fixed electrode 3 is arranged in a row between the plurality of movable electrodes 2. That is, the fixed electrodes 3 are arranged in a plurality of rows in the Y direction. Each fixed electrode 3 has opposing surfaces 30 that face one trough portion 22 of the movable electrode 2 on both sides in the Y direction, and has a symmetrical shape in the moving direction X.
　当該共振周波数調整モジュール１において、可動電極２は、支持部材５により一体に保持され、弾性体４を介してＭＥＭＳセンサの移動体（不図示）に固定される。一方、固定電極３は、ＭＥＭＳセンサの基板（不図示）に不動に固定される。なお、図１には、当該共振周波数調整モジュール１の可動電極２を含む移動部分の質量を概念的に表した錘６を図示する。 In the resonance frequency adjusting module 1, the movable electrode 2 is integrally held by the support member 5 and fixed to the moving body (not shown) of the MEMS sensor via the elastic body 4. On the other hand, the fixed electrode 3 is fixedly fixed to a substrate (not shown) of the MEMS sensor. FIG. 1 shows a weight 6 conceptually representing the mass of the moving part including the movable electrode 2 of the resonance frequency adjustment module 1.
　当該共振周波数調整モジュール１は、可動電極２と固定電極３とに電位差を与えることにより、可動電極２と固定電極３との対向面２０，３０間に静電引力（クーロン力）が作用するため、この電位差を調節することで当該共振周波数調整モジュール１の見かけ上のばね定数を調節することができる。 In the resonance frequency adjustment module 1, electrostatic attractive force (Coulomb force) acts between the opposed surfaces 20 and 30 of the movable electrode 2 and the fixed electrode 3 by applying a potential difference between the movable electrode 2 and the fixed electrode 3. By adjusting this potential difference, the apparent spring constant of the resonance frequency adjusting module 1 can be adjusted.
　可動電極２及び固定電極３の材質は、特に限定されないが、例えばシリコンを用いることができる。 The material of the movable electrode 2 and the fixed electrode 3 is not particularly limited, but for example, silicon can be used.
　可動電極２及び固定電極３の平均厚さ（図１における紙面奥行方向の寸法）としては、特に限定されないが、例えば２０μｍ以上５０μｍ以下とすることができる。また、可動電極２及び固定電極３の平均厚さは、製造プロセスが許容する範囲でさらに小さくしてもよい。 The average thickness of the movable electrode 2 and the fixed electrode 3 (the dimension in the depth direction in FIG. 1) is not particularly limited, but may be, for example, 20 μm or more and 50 μm or less. Further, the average thickness of the movable electrode 2 and the fixed electrode 3 may be further reduced as long as the manufacturing process allows.
　可動電極２及び固定電極３の形成方法は、特に限定されないが、例えば板状の材料の表面にフォトリソグラフィー技術によってレジストパターンを形成し、選択的にエッチングする方法を適用することができる。 The formation method of the movable electrode 2 and the fixed electrode 3 is not particularly limited, and for example, a method of selectively etching by forming a resist pattern on the surface of a plate-like material by a photolithography technique can be applied.
　可動電極２の対向面２０及び固定電極３の対向面３０の、可動電極２の移動方向Ｘに対する平均傾斜角の下限としては、２度が好ましく、４度がより好ましい。一方、可動電極２の対向面２０及び固定電極３の対向面３０の、可動電極２の移動方向Ｘに対する平均傾斜角の上限としては、１２度が好ましく、８度がより好ましい。可動電極２の対向面２０及び固定電極３の対向面３０の、可動電極２の移動方向Ｘに対する平均傾斜角が上記下限に満たない場合、可動電極の移動量に対する対向面２０，３０間の距離の変化が小さく、当該共振周波数調整モジュール１の面積効率が低くなるおそれがある。また、可動電極２の対向面２０及び固定電極３の対向面３０の、可動電極２の移動方向Ｘに対する平均傾斜角が上記上限を超える場合、可動電極２の可動範囲が狭くなり、当該共振周波数調整モジュール１の振幅が不十分となるおそれがある。 The lower limit of the average inclination angle of the opposed surface 20 of the movable electrode 2 and the opposed surface 30 of the fixed electrode 3 with respect to the moving direction X of the movable electrode 2 is preferably 2 degrees and more preferably 4 degrees. On the other hand, the upper limit of the average inclination angle of the facing surface 20 of the movable electrode 2 and the facing surface 30 of the fixed electrode 3 with respect to the moving direction X of the movable electrode 2 is preferably 12 degrees, and more preferably 8 degrees. When the average inclination angle of the opposing surface 20 of the movable electrode 2 and the opposing surface 30 of the fixed electrode 3 with respect to the moving direction X of the movable electrode 2 is less than the lower limit, the distance between the opposing surfaces 20 and 30 with respect to the moving amount of the movable electrode. There is a possibility that the area efficiency of the resonance frequency adjustment module 1 is lowered. Further, when the average inclination angle of the opposed surface 20 of the movable electrode 2 and the opposed surface 30 of the fixed electrode 3 with respect to the moving direction X of the movable electrode 2 exceeds the upper limit, the movable range of the movable electrode 2 is narrowed, and the resonance frequency is reduced. There is a possibility that the amplitude of the adjustment module 1 becomes insufficient.
　山部２１及び谷部２２の各々の平均ピッチ（山部２１の平均間隔及び谷部２２の平均間隔）の下限としては、可動電極２の基準位置からの使用上の最大移動量の１．５倍が好ましく、２倍がより好ましい。一方、山部２１及び谷部２２の平均ピッチの上限としては、可動電極２の基準位置からの使用上の最大移動量の４倍が好ましく、３倍がより好ましい。山部２１及び谷部２２の各々の平均ピッチが上記下限に満たない場合、対向面２０，３０間の間隔の変化率が大きくなり、可動電極２の移動量に対する可動電極２及び固定電極３間の静電引力の線形性が不十分となるおそれがある。また、山部２１及び谷部２２の各々の平均ピッチが上記上限を超える場合、当該共振周波数調整モジュール１が不必要に大きくなるおそれがある。 As a lower limit of each average pitch (average interval of peak portions 21 and average interval of valley portions 22) of peak portion 21 and valley portion 22, the maximum movement amount in use from the reference position of movable electrode 2 is 1.5. Double is preferable, and double is more preferable. On the other hand, the upper limit of the average pitch of the peak portion 21 and the valley portion 22 is preferably four times the maximum movement amount in use from the reference position of the movable electrode 2, and more preferably three times. When the average pitch of each of the peak portion 21 and the valley portion 22 is less than the lower limit, the rate of change of the interval between the opposing surfaces 20 and 30 increases, and the distance between the movable electrode 2 and the fixed electrode 3 with respect to the movement amount of the movable electrode 2 is increased. There is a possibility that the linearity of the electrostatic attractive force of the battery becomes insufficient. Moreover, when each average pitch of the peak part 21 and the trough part 22 exceeds the said upper limit, there exists a possibility that the said resonant frequency adjustment module 1 may become unnecessarily large.
　可動電極２の対向面２０と固定電極３の対向面３０との平均間隔の下限としては、０．５μｍが好ましく、１μｍがより好ましい。一方、可動電極２の対向面２０と固定電極３の対向面３０との平均間隔の上限としては、３μｍが好ましく、２．５μｍがより好ましい。可動電極２の対向面２０と固定電極３の対向面３０との平均間隔が上記下限に満たない場合、可動電極２の対向面２０の第１傾斜部２３と固定電極３の対向面３０の第１傾斜部３１との間隔や可動電極２の対向面２０の第２傾斜部２４と固定電極３の対向面３０の第２傾斜部３２との間隔の変化率が大きくなり、可動電極２の移動量に対する静電引力の線形性が不十分となるおそれがある。また、可動電極２の対向面２０と固定電極３の対向面３０との平均間隔が上記上限を超える場合、静電引力が小さくなり、当該共振周波数調整モジュール１の面積効率が小さくなるおそれがある。なお、対向面２０と対向面３０との「平均間隔」とは、対向面２０の法線と対向面３０の法線との二等分線方向の距離の平均を意味する。 The lower limit of the average distance between the facing surface 20 of the movable electrode 2 and the facing surface 30 of the fixed electrode 3 is preferably 0.5 μm and more preferably 1 μm. On the other hand, the upper limit of the average distance between the facing surface 20 of the movable electrode 2 and the facing surface 30 of the fixed electrode 3 is preferably 3 μm, and more preferably 2.5 μm. When the average distance between the facing surface 20 of the movable electrode 2 and the facing surface 30 of the fixed electrode 3 is less than the lower limit, the first inclined portion 23 of the facing surface 20 of the movable electrode 2 and the first surface of the facing surface 30 of the fixed electrode 3 The rate of change of the interval between the first inclined portion 31 and the interval between the second inclined portion 24 of the opposed surface 20 of the movable electrode 2 and the second inclined portion 32 of the opposed surface 30 of the fixed electrode 3 increases, and the movable electrode 2 moves. There is a possibility that the linearity of the electrostatic attractive force with respect to the quantity becomes insufficient. Moreover, when the average space | interval of the opposing surface 20 of the movable electrode 2 and the opposing surface 30 of the fixed electrode 3 exceeds the said upper limit, there exists a possibility that an electrostatic attractive force may become small and the area efficiency of the said resonant frequency adjustment module 1 may become small. . The “average distance” between the facing surface 20 and the facing surface 30 means the average distance in the bisector direction between the normal line of the facing surface 20 and the normal line of the facing surface 30.
　可動電極２の対向面２０の山部２１又は谷部２２の平均ピッチと複数の固定電極３の移動方向Ｘの平均長さとの差の下限としては、移動方向Ｘにおける可動電極２と複数の固定電極３との間の平均距離の０．５倍が好ましく、０．６倍がより好ましい。一方、可動電極２の対向面２０の山部２１又は谷部２２の平均ピッチと複数の固定電極３の移動方向Ｘの平均長さとの差の上限としては、移動方向Ｘにおける可動電極２と複数の固定電極３との間の平均距離の１．２倍が好ましく、１．０倍がより好ましい。可動電極２の対向面２０の山部２１又は谷部２２の平均ピッチと複数の固定電極３の移動方向Ｘの平均長さとの差が上記下限に満たない場合、可動電極２が基準位置（移動量ゼロ）にある状態で固定電極３に対向しない可動電極２の対向面２０の山部２１又は谷部２２の影響により、可動電極２の移動量に対する静電引力の線形性が不十分となるおそれがある。また、可動電極２の対向面２０の山部２１又は谷部２２の平均ピッチと複数の固定電極３の移動方向Ｘの平均長さとの差が上記上限を超える場合、静電引力が小さくなり、当該共振周波数調整モジュール１の面積効率が小さくなるおそれがある。 The lower limit of the difference between the average pitch of the crests 21 or troughs 22 of the opposing surface 20 of the movable electrode 2 and the average length of the plurality of fixed electrodes 3 in the movement direction X is the movable electrode 2 and the plurality of fixed in the movement direction X. 0.5 times the average distance from the electrode 3 is preferable, and 0.6 times is more preferable. On the other hand, as the upper limit of the difference between the average pitch of the crests 21 or troughs 22 of the opposed surface 20 of the movable electrode 2 and the average length in the movement direction X of the plurality of fixed electrodes 3, 1.2 times the average distance from the fixed electrode 3 is preferably 1.0 times. When the difference between the average pitch of the crests 21 or troughs 22 of the opposed surface 20 of the movable electrode 2 and the average length in the moving direction X of the plurality of fixed electrodes 3 is less than the lower limit, the movable electrode 2 is moved to the reference position (moving The linearity of the electrostatic attractive force with respect to the movement amount of the movable electrode 2 becomes insufficient due to the influence of the peak portion 21 or the valley portion 22 of the facing surface 20 of the movable electrode 2 that does not face the fixed electrode 3 in a state of zero amount). There is a fear. In addition, when the difference between the average pitch of the crests 21 or troughs 22 of the opposed surface 20 of the movable electrode 2 and the average length of the plurality of fixed electrodes 3 in the moving direction X exceeds the above upper limit, the electrostatic attractive force is reduced, There is a possibility that the area efficiency of the resonance frequency adjustment module 1 is reduced.
　＜利点＞
　本実施形態における共振周波数調整モジュール１は、可動電極２の対向面２０が移動方向Ｘに交互に配列する山部２１及び谷部２２を有し、各固定電極３が可動電極２の１つの谷部２２に対向するよう配設されるので、可動電極２の移動により、第１傾斜部２３，３１間の距離及び第２傾斜部２４，３２間の距離の一方が増大し、他方が減少する。これにより、可動電極２と固定電極３との間に作用する静電引力は、可動電極２を移動方向Ｘにさらに移動させる方向に作用し、かつ移動量が大きいほどその力が大きくなる。従って、当該共振周波数調整モジュール１は、弾性体４の復元力を部分的に相殺して見かけ上のばね定数を変化させて、可動電極２を含む錘６の共振周波数を調整することができる。また、当該共振周波数調整モジュール１は、従来の櫛歯状のものと比べて面積効率が高い。 <Advantages>
The resonance frequency adjustment module 1 according to the present embodiment has crests 21 and troughs 22 in which the opposed surfaces 20 of the movable electrode 2 are alternately arranged in the movement direction X, and each fixed electrode 3 is one trough of the movable electrode 2. Since the movable electrode 2 is disposed so as to face the portion 22, one of the distance between the first inclined portions 23 and 31 and the distance between the second inclined portions 24 and 32 increases and the other decreases due to the movement of the movable electrode 2. . Thereby, the electrostatic attractive force acting between the movable electrode 2 and the fixed electrode 3 acts in a direction in which the movable electrode 2 is further moved in the movement direction X, and the force increases as the movement amount increases. Therefore, the resonance frequency adjusting module 1 can adjust the resonance frequency of the weight 6 including the movable electrode 2 by partially canceling the restoring force of the elastic body 4 and changing the apparent spring constant. Further, the resonance frequency adjusting module 1 has a higher area efficiency than a conventional comb-shaped one.
　また、当該共振周波数調整モジュール１は、可動電極２及び固定電極３の対向面２０，３０が移動方向Ｘに対して傾斜しているので、可動電極の移動による対向面２０，３０間の体積変化が小さく、空気抵抗が小さい。 Further, in the resonance frequency adjusting module 1, since the opposing surfaces 20, 30 of the movable electrode 2 and the fixed electrode 3 are inclined with respect to the movement direction X, the volume change between the opposing surfaces 20, 30 due to the movement of the movable electrode. Is small and air resistance is small.
　また、当該共振周波数調整モジュール１は、各固定電極３が、可動電極２の１つの谷部２２に対向するので、固定電極３の対向面３０の変曲点が一カ所だけであり、可動電極２との間の電気的特性が平行平板に近いものとなるので、可動電極２の移動量に対する可動電極２及び固定電極３間の静電引力の線形性が比較的高くなる。 Further, in the resonance frequency adjusting module 1, each fixed electrode 3 faces one valley 22 of the movable electrode 2, so there is only one inflection point on the facing surface 30 of the fixed electrode 3. Therefore, the linearity of the electrostatic attractive force between the movable electrode 2 and the fixed electrode 3 with respect to the amount of movement of the movable electrode 2 is relatively high.
　また、固定電極３が可動電極２の谷部２２に対向することによって、固定電極３の移動方向Ｘの中央部での幅を極大化できるので、例えばビアホールによる固定電極３の固定及び配線が容易となる。 Further, since the fixed electrode 3 faces the trough portion 22 of the movable electrode 2, the width at the central portion in the moving direction X of the fixed electrode 3 can be maximized, so that the fixed electrode 3 can be easily fixed and wired by, for example, a via hole. It becomes.
　＜ジャイロセンサ＞
　続いて、本発明の一実施形態に係るジャイロセンサ（ＭＥＭＳセンサ）について説明する。 <Gyro sensor>
Subsequently, a gyro sensor (MEMS sensor) according to an embodiment of the present invention will be described.
　当該共振周波数調整モジュール１は、上述のようにジャイロセンサ（ＭＥＭＳセンサ）に用いられる。このジャイロセンサは、例えばＸ－Ｙ方向に延在する基板上にＸ方向に移動可能に支持されＸ方向に並ぶ２つの移動体と、Ｙ方向に検出用可動電極が移動可能なように移動体に支持された２つの静電容量変化検出モジュールと、移動体をＸ方向に往復移動させる振動駆動モジュールとを備える構成とすることができる。そして、当該共振周波数調整モジュール１は、固定電極３が上記基板に固定され、可動電極２が上記移動体に固定される。 The resonance frequency adjusting module 1 is used for a gyro sensor (MEMS sensor) as described above. This gyro sensor is, for example, a movable body that is supported on a substrate extending in the XY direction so as to be movable in the X direction, and that the movable electrode for detection is movable in the Y direction. The two electrostatic capacity change detection modules supported by the sensor and a vibration drive module that reciprocates the moving body in the X direction can be used. In the resonance frequency adjusting module 1, the fixed electrode 3 is fixed to the substrate, and the movable electrode 2 is fixed to the moving body.
　当該共振周波数調整モジュール１にあっては、可動電極２と固定電極３との電位差を調整することで、見かけ上のばね定数を所望の値に調整できる。このため、移動体及び静電容量変化検出モジュールの共振周波数を容易かつ確実にコントロールすることができる。 In the resonance frequency adjustment module 1, the apparent spring constant can be adjusted to a desired value by adjusting the potential difference between the movable electrode 2 and the fixed electrode 3. For this reason, the resonant frequency of a mobile body and an electrostatic capacitance change detection module can be controlled easily and reliably.
　［第２実施形態］
　図２に示す共振周波数調整モジュール１ａは、角速度を検出するＭＥＭＳセンサを構成する共振周波数調整モジュールである。当該共振周波数調整モジュール１ａは、移動可能に配設され、移動方向（Ｘ方向）に延在する複数の可動電極２ａと、この可動電極２ａの移動方向Ｘに沿って配列する複数の固定電極３ａと、可動電極２ａを移動方向Ｘに移動可能に支持する弾性体４とを主に備える。 [Second Embodiment]
A resonance frequency adjustment module 1a shown in FIG. 2 is a resonance frequency adjustment module that constitutes a MEMS sensor that detects angular velocity. The resonance frequency adjusting module 1a is movably arranged, and a plurality of movable electrodes 2a extending in the movement direction (X direction), and a plurality of fixed electrodes 3a arranged along the movement direction X of the movable electrode 2a. And an elastic body 4 that supports the movable electrode 2a so as to be movable in the movement direction X.
　可動電極２ａの固定電極３ａとの対向面２０は、略一定のピッチ及び傾斜角で移動方向Ｘに交互に配列する山部２１及び谷部２２を有する。複数の固定電極３ａは、それぞれ可動電極２の山部２１に対向するよう配設される。固定電極３ａの可動電極２ａとの対向面３０は、可動電極２ａの対向面２０の第１傾斜部２３に対向する第１傾斜部３１と、第１傾斜部２３と反対側に傾斜する第２傾斜部２４に対向する第２傾斜部３２とを有する。この固定電極３ａは、移動方向Ｘの中央部に向かってこの移動方向Ｘに直交するＹ方向の幅が狭くなっている。 The opposed surface 20 of the movable electrode 2a to the fixed electrode 3a has crests 21 and troughs 22 arranged alternately in the movement direction X at a substantially constant pitch and inclination angle. The plurality of fixed electrodes 3a are disposed so as to face the crests 21 of the movable electrode 2, respectively. The opposed surface 30 of the fixed electrode 3a to the movable electrode 2a includes a first inclined portion 31 that faces the first inclined portion 23 of the opposed surface 20 of the movable electrode 2a, and a second inclined surface that is inclined opposite to the first inclined portion 23. And a second inclined portion 32 facing the inclined portion 24. The width of the fixed electrode 3a in the Y direction perpendicular to the moving direction X is narrowed toward the center of the moving direction X.
　当該共振周波数調整モジュール１ａにおいて、可動電極２ａは、支持部材５により一体に保持され、弾性体４を介してＭＥＭＳセンサの移動体（不図示）に固定される。一方、固定電極３ａは、ＭＥＭＳセンサの基板（不図示）に不動に固定される。なお、図２には、当該共振周波数調整モジュール１ａの可動電極２ａを含む移動部分の質量を概念的に表した錘６を図示する。 In the resonance frequency adjustment module 1a, the movable electrode 2a is integrally held by the support member 5 and fixed to a moving body (not shown) of the MEMS sensor via the elastic body 4. On the other hand, the fixed electrode 3a is fixed on a substrate (not shown) of the MEMS sensor. FIG. 2 shows a weight 6 conceptually representing the mass of the moving part including the movable electrode 2a of the resonance frequency adjusting module 1a.
　当該共振周波数調整モジュール１ａは、可動電極２ａと固定電極３ａとに電位差を与えることにより、可動電極２ａと固定電極３ａとの対向面２０，３０間に静電引力（クーロン力）が作用するため、この電位差を調節することで当該共振周波数調整モジュール１ａの見かけ上のばね定数を調節することができる。 Since the resonance frequency adjusting module 1a gives a potential difference between the movable electrode 2a and the fixed electrode 3a, an electrostatic attractive force (Coulomb force) acts between the opposing surfaces 20 and 30 of the movable electrode 2a and the fixed electrode 3a. By adjusting this potential difference, the apparent spring constant of the resonance frequency adjusting module 1a can be adjusted.
　図２に示す共振周波数調整モジュール１ａにおける可動電極２ａ及び固定電極３ａの材質や製造方法は、図１に示す共振周波数調整モジュール１における可動電極２及び固定電極３の材質や製造方法と同様である。 The material and manufacturing method of the movable electrode 2a and the fixed electrode 3a in the resonance frequency adjustment module 1a shown in FIG. 2 are the same as the material and manufacturing method of the movable electrode 2 and the fixed electrode 3 in the resonance frequency adjustment module 1 shown in FIG. .
　［第３実施形態］
　図３に示す共振周波数調整モジュール１ｂは、角速度を検出するＭＥＭＳセンサを構成する共振周波数調整モジュールである。当該共振周波数調整モジュール１ｂは、移動可能に配設され、移動方向（Ｘ方向）に延在する複数の可動電極２ｂと、この可動電極２ｂの移動方向Ｘに沿って配列する複数の固定電極３，３ａと、可動電極２ｂを移動方向Ｘに移動可能に支持する弾性体４とを主に備える。 [Third Embodiment]
A resonance frequency adjustment module 1b shown in FIG. 3 is a resonance frequency adjustment module constituting a MEMS sensor that detects angular velocity. The resonance frequency adjusting module 1b is movably arranged, and a plurality of movable electrodes 2b extending in the movement direction (X direction), and a plurality of fixed electrodes 3 arranged along the movement direction X of the movable electrode 2b. , 3a and an elastic body 4 that supports the movable electrode 2b so as to be movable in the movement direction X.
　図３に示す共振周波数調整モジュール１ｂにおいて、可動電極２ｂの固定電極３，３ａとの対向面２０は、略一定のピッチ及び傾斜角で移動方向Ｘに交互に配列する山部２１及び谷部２２を有する。この可動電極２ｂは、移動方向Ｘに直交するＹ方向に山部２１と谷部２２とが背中合わせに配置されることで、一定幅でジグザグに折れ曲がったような平面形状を有する。また、これらの可動電極２ｂは、隣り合う可動電極２ｂ同士が山部２１及び谷部２２を対向させるよう互い違いに配置されている。 In the resonance frequency adjusting module 1b shown in FIG. 3, the facing surface 20 of the movable electrode 2b facing the fixed electrodes 3 and 3a has crests 21 and troughs 22 that are alternately arranged in the movement direction X with a substantially constant pitch and inclination angle. Have The movable electrode 2b has a planar shape that is bent zigzag with a constant width by arranging the peak portion 21 and the valley portion 22 back to back in the Y direction orthogonal to the movement direction X. Moreover, these movable electrodes 2b are alternately arranged so that the adjacent movable electrodes 2b face the peak portion 21 and the valley portion 22.
　図３に示す共振周波数調整モジュール１ｂは、可動電極２ｂの対向面２０の谷部２２に対向するよう列をなして配列される複数の第１固定電極３と、可動電極２ｂの固定電極３とＹ方向反対側の対向面２０の山部２１に対向するよう列をなして配列される複数の第２固定電極３ａとを有する。つまり、第１固定電極３と第２固定電極３ａとは、一列おきに配列されている。図３に示す共振周波数調整モジュール１ｂの第１固定電極３は、図１に示す共振周波数調整モジュール１における固定電極３と同様の形状を有する。図３に示す共振周波数調整モジュール１ｂの第２固定電極３ａは、図２に示す共振周波数調整モジュール１ａにおける固定電極３ａと同様の形状を有する。 The resonance frequency adjusting module 1b shown in FIG. 3 includes a plurality of first fixed electrodes 3 arranged in a row so as to face the valleys 22 of the facing surface 20 of the movable electrode 2b, and the fixed electrodes 3 of the movable electrode 2b. A plurality of second fixed electrodes 3a arranged in a row so as to face the crests 21 of the opposing surface 20 on the opposite side in the Y direction. That is, the first fixed electrode 3 and the second fixed electrode 3a are arranged every other row. The first fixed electrode 3 of the resonance frequency adjustment module 1b shown in FIG. 3 has the same shape as the fixed electrode 3 in the resonance frequency adjustment module 1 shown in FIG. The second fixed electrode 3a of the resonance frequency adjustment module 1b shown in FIG. 3 has the same shape as the fixed electrode 3a in the resonance frequency adjustment module 1a shown in FIG.
　当該共振周波数調整モジュール１ｂにおいて、可動電極２ｂは、支持部材５により一体に保持され、弾性体４を介してＭＥＭＳセンサの移動体（不図示）に固定される。一方、固定電極３、３ａは、ＭＥＭＳセンサの基板（不図示）に不動に固定される。なお、図３には、当該共振周波数調整モジュール１ｂの可動電極２ｂを含む移動部分の質量を概念的に表した錘６を図示する。 In the resonance frequency adjustment module 1b, the movable electrode 2b is integrally held by the support member 5, and is fixed to a moving body (not shown) of the MEMS sensor via the elastic body 4. On the other hand, the fixed electrodes 3 and 3a are fixedly fixed to a substrate (not shown) of the MEMS sensor. FIG. 3 shows a weight 6 conceptually representing the mass of the moving part including the movable electrode 2b of the resonance frequency adjustment module 1b.
　当該共振周波数調整モジュール１ｂは、可動電極２ｂと固定電極３，３ａとに電位差を与えることにより、可動電極２ｂと固定電極３，３ａとの対向面２０，３０間に静電引力（クーロン力）が作用するため、この電位差を調節することで当該共振周波数調整モジュール１ｂの見かけ上のばね定数を調節することができる。 The resonance frequency adjusting module 1b gives an electrostatic attraction (Coulomb force) between the opposed surfaces 20 and 30 of the movable electrode 2b and the fixed electrodes 3 and 3a by applying a potential difference between the movable electrode 2b and the fixed electrodes 3 and 3a. Therefore, the apparent spring constant of the resonance frequency adjusting module 1b can be adjusted by adjusting the potential difference.
　図３に示す共振周波数調整モジュール１ｂにおける可動電極２ｂの材質や製造方法は、図１に示す共振周波数調整モジュール１における可動電極２の材質や製造方法と同様である。 The material and manufacturing method of the movable electrode 2b in the resonance frequency adjusting module 1b shown in FIG. 3 are the same as the material and manufacturing method of the movable electrode 2 in the resonance frequency adjusting module 1 shown in FIG.
　［第４実施形態］
　図４に示す共振周波数調整モジュール１ｃは、角速度を検出するＭＥＭＳセンサを構成する共振周波数調整モジュールである。当該共振周波数調整モジュール１ｃは、移動可能に配設され、移動方向（Ｘ方向）に延在する複数の可動電極２ｂと、この可動電極２ｂの移動方向Ｘに沿って配列する複数の固定電極３と、可動電極２ｂを移動方向Ｘに移動可能に支持する弾性体４とを主に備える。 [Fourth Embodiment]
A resonance frequency adjustment module 1c shown in FIG. 4 is a resonance frequency adjustment module constituting a MEMS sensor that detects angular velocity. The resonance frequency adjustment module 1c is movably arranged, and a plurality of movable electrodes 2b extending in the movement direction (X direction), and a plurality of fixed electrodes 3 arranged along the movement direction X of the movable electrode 2b. And an elastic body 4 that supports the movable electrode 2b so as to be movable in the movement direction X.
　図４に示す共振周波数調整モジュール１ｃにおける可動電極２ｂは、図３に示す共振周波数調整モジュール１ｂにおける可動電極２ｂと同様の形状及び配置を有する。また、図４に示す共振周波数調整モジュール１ｃにおける固定電極３は、図１に示す共振周波数調整モジュール１における固定電極３と同様の形状を有する。 The movable electrode 2b in the resonance frequency adjustment module 1c shown in FIG. 4 has the same shape and arrangement as the movable electrode 2b in the resonance frequency adjustment module 1b shown in FIG. Further, the fixed electrode 3 in the resonance frequency adjustment module 1c shown in FIG. 4 has the same shape as the fixed electrode 3 in the resonance frequency adjustment module 1 shown in FIG.
　図４に示す共振周波数調整モジュール１ｃにおいて、固定電極３は、いずれも可動電極２ｂの凹部２２に対向するよう、複数の可動電極２ｂの間にそれぞれ一列ずつ配列されている。このため、固定電極３の移動方向Ｘの配置は、可動電極２ｂの形状に合わせて、移動方向Ｘの位置が一列おきに２分の１ピッチずつずらされている。 In the resonance frequency adjusting module 1c shown in FIG. 4, the fixed electrodes 3 are arranged in a row between the plurality of movable electrodes 2b so that all of the fixed electrodes 3 face the recesses 22 of the movable electrode 2b. For this reason, the arrangement of the fixed electrodes 3 in the movement direction X is shifted by a half pitch every other row in accordance with the shape of the movable electrode 2b.
　当該共振周波数調整モジュール１ｃにおいて、可動電極２ｂは、支持部材５により一体に保持され、弾性体４を介してＭＥＭＳセンサの移動体（不図示）に固定される。一方、固定電極３は、ＭＥＭＳセンサの基板（不図示）に不動に固定される。なお、図４には、当該共振周波数調整モジュール１ｃの可動電極２ｂを含む移動部分の質量を概念的に表した錘６を図示する。 In the resonance frequency adjusting module 1c, the movable electrode 2b is integrally held by the support member 5, and is fixed to the moving body (not shown) of the MEMS sensor via the elastic body 4. On the other hand, the fixed electrode 3 is fixedly fixed to a substrate (not shown) of the MEMS sensor. FIG. 4 shows a weight 6 conceptually representing the mass of the moving part including the movable electrode 2b of the resonance frequency adjusting module 1c.
　当該共振周波数調整モジュール１ｃは、可動電極２ｂと固定電極３とに電位差を与えることにより、可動電極２ｂと固定電極３との対向面２０，３０間に静電引力（クーロン力）が作用するため、この電位差を調節することで当該共振周波数調整モジュール１ｃの見かけ上のばね定数を調節することができる。 Since the resonance frequency adjusting module 1c gives a potential difference between the movable electrode 2b and the fixed electrode 3, an electrostatic attractive force (Coulomb force) acts between the opposing surfaces 20 and 30 of the movable electrode 2b and the fixed electrode 3. By adjusting this potential difference, the apparent spring constant of the resonance frequency adjusting module 1c can be adjusted.
　［その他の実施形態］
　上記各実施形態は、本発明の構成を限定するものではない。従って、上記各実施形態は、本明細書の記載及び技術常識に基づいて上記各実施形態における各部の構成要素の省略、置換又は追加が可能であり、それらはすべて本発明の範囲に属するものと解釈されるべきである。 [Other Embodiments]
Each said embodiment does not limit the structure of this invention. Therefore, in each of the above-described embodiments, the constituent elements of each part in each of the above-described embodiments can be omitted, replaced, or added based on the description of the present specification and the common general knowledge, and they all belong to the scope of the present invention. Should be interpreted.
　上記各実施形態における共振周波数調整モジュールにおいて、可動電極及び固定電極の列数及び固定電極の列内の個数は任意に変更可能である。また、可動電極の両側に固定電極が配列されるようにしてもよい。 In the resonance frequency adjustment module in each of the above embodiments, the number of movable electrode and fixed electrode rows and the number of fixed electrode rows can be arbitrarily changed. Further, fixed electrodes may be arranged on both sides of the movable electrode.
　また、上記各実施形態における共振周波数調整モジュールにおいて、可動電極及び固定電極の対向面は、平面に限られず、曲面であってもよい。 Further, in the resonance frequency adjustment module in each of the above embodiments, the facing surfaces of the movable electrode and the fixed electrode are not limited to flat surfaces, and may be curved surfaces.
　以下、実施例に基づき本発明について詳述するが、この実施例の記載に基づいて本発明が限定的に解釈されるものではない。 Hereinafter, the present invention will be described in detail based on examples, but the present invention is not limitedly interpreted based on the description of the examples.
　上記第１実施形態の形状を有する共振周波数調整モジュールの可動電極及び固定電極のモデルＮｏ．１及びＮｏ．２をシミュレーター上でモデリングし、発生する静電引力をシミュレーションにより確認した。 Model No. of movable electrode and fixed electrode of resonance frequency adjustment module having the shape of the first embodiment. 1 and no. 2 was modeled on a simulator, and the generated electrostatic attraction was confirmed by simulation.
　モデルＮｏ．１及びＮｏ．２は、次の表１に示す形状とした。なお、各モデルは、３本の可動電極と、この３本の可動電極の間にそれぞれ３つずつ２列に配列する合計６個の固定電極とを有するものとしてモデリングした。 Model No. 1 and no. 2 had the shape shown in Table 1 below. Each model was modeled as having three movable electrodes and a total of six fixed electrodes arranged in two rows of three each between the three movable electrodes.
　（モデルＮｏ．１）
　具体的には、モデルＮｏ．１は、可動電極及び固定電極の対向面の移動方向Ｘに対する角度を６．０４度で一定とし、可動電極及び固定電極の対向面間の間隔（上記「平均間隔」）を２．１μｍで一定とし、山部（及び谷部）のピッチを４０μｍで一定とし、固定電極の移動方向Ｘの長さを２４μｍで一定とした。対向面の傾斜角及び対向面間の間隔から導出される可動電極及び固定電極の対向面間の移動方向Ｘの平均距離は、２０μｍである。また、モデルＮｏ．１の山部のピッチと固定電極の移動方向Ｘの長さとの差は、移動方向Ｘにおける可動電極と複数の固定電極との間の平均距離の０．８倍である。 (Model No. 1)
Specifically, model no. 1 is that the angle with respect to the moving direction X of the opposing surfaces of the movable electrode and the fixed electrode is constant at 6.04 degrees, and the interval between the opposing surfaces of the movable electrode and the fixed electrode (the above-mentioned “average interval”) is constant at 2.1 μm. The pitch of the peaks (and valleys) was constant at 40 μm, and the length of the fixed electrode in the moving direction X was constant at 24 μm. The average distance in the moving direction X between the opposing surfaces of the movable electrode and the fixed electrode, which is derived from the inclination angle of the opposing surfaces and the interval between the opposing surfaces, is 20 μm. Model No. The difference between the pitch of one peak and the length of the fixed electrode in the moving direction X is 0.8 times the average distance between the movable electrode and the plurality of fixed electrodes in the moving direction X.
　（モデルＮｏ．２）
　モデルＮｏ．２は、可動電極及び固定電極の対向面の移動方向Ｘに対する角度を４．６０度で一定とし、可動電極及び固定電極の対向面間の間隔を１．６μｍで一定とし、山部（及び谷部）のピッチを４０μｍで一定とし、固定電極の移動方向Ｘの長さを２４μｍで一定とした。対向面の傾斜角及び対向面の間隔から導出される可動電極及び固定電極の対向面間の移動方向Ｘの平均距離は、２０μｍである。また、モデルＮｏ．２の山部のピッチと固定電極の移動方向Ｘの長さとの差は、移動方向Ｘにおける可動電極と複数の固定電極との間の平均距離の０．８倍である。 (Model No. 2)
Model No. 2, the angle of the opposing surfaces of the movable electrode and the fixed electrode with respect to the moving direction X is constant at 4.60 degrees, the interval between the opposing surfaces of the movable electrode and the fixed electrode is constant at 1.6 μm, and the peaks (and valleys) Part) was made constant at 40 μm, and the length of the fixed electrode in the moving direction X was made constant at 24 μm. The average distance in the moving direction X between the opposed surfaces of the movable electrode and the fixed electrode derived from the inclination angle of the opposed surface and the interval between the opposed surfaces is 20 μm. Model No. The difference between the pitch of the two peaks and the length of the fixed electrode in the moving direction X is 0.8 times the average distance between the movable electrode and the plurality of fixed electrodes in the moving direction X.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　これらのモデルＮｏ．１及びＮｏ．２について、可動部材の移動量と可動電極及び固定電極間の静電引力との関係をシミュレートした結果を次の表２に示す。なお、静電引力の線形性は、移動量ゼロの近傍における静電引力の変化率が不変であると仮定した場合にそれぞれの移動量で予想される静電引力に対する百分率で示す。 These model Nos. 1 and no. Table 2 shows the result of simulating the relationship between the amount of movement of the movable member and the electrostatic attractive force between the movable electrode and the fixed electrode. Note that the linearity of electrostatic attraction is expressed as a percentage of the electrostatic attraction expected for each amount of movement assuming that the rate of change of the electrostatic attraction near the amount of movement zero is unchanged.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　このように、可動電極の固定電極との対向面が移動方向に交互に配列する山部及び谷部を有し、複数の固定電極を可動電極の山部に対向するよう配設したモデルＮｏ．１及びＮｏ．２は、可動電極の移動量が１２μｍまでの範囲において、この移動量に対する静電引力の比（見かけ上のばね定数）の変化が±１０％以内の高い線形性を有していることが確認された。 As described above, Model No. 2 has a crest and a trough where the surface of the movable electrode facing the fixed electrode is alternately arranged in the moving direction, and a plurality of fixed electrodes are arranged to face the crest of the movable electrode. 1 and no. 2 confirms that the change in the ratio of the electrostatic attractive force to this moving amount (apparent spring constant) within the range up to 12 μm is high linearity within ± 10%. It was done.
　今回開示した上記実施形態および実施例はすべての点で例示であって、制限的なものではない。本発明の技術的範囲は請求の範囲によって画定され、また請求の範囲の記載と均等の意味および範囲内でのすべての変更を含むものである。 The embodiment and examples disclosed herein are illustrative in all respects and are not restrictive. The technical scope of the present invention is defined by the scope of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
　本発明に係る共振周波数調整モジュールは、角速度を検出するＭＥＭＳセンサに好適に利用できる。 The resonance frequency adjustment module according to the present invention can be suitably used for a MEMS sensor that detects angular velocity.
　１，１ａ，１ｂ，１ｃ　共振周波数調整モジュール、２，２ａ，２ｂ　可動電極、２０　対向面、２１　山部、２２　谷部、２３　第１傾斜部、２４　第２傾斜部、３，３ａ　固定電極、３０　対向面、３１　第１傾斜部、３２　第２傾斜部、４　弾性体、５　支持部材、６　錘、Ｘ　移動方向。 1, 1a, 1b, 1c Resonance frequency adjustment module, 2, 2a, 2b movable electrode, 20 facing surface, 21 mountain part, 22 valley part, 23 first inclined part, 24 second inclined part, 3, 3a fixed electrode, 30 opposing surface, 31 1st inclined part, 32 2nd inclined part, 4 elastic body, 5 support member, 6 weight, X movement direction.

Claims (5)

  1. 　角速度を検出するＭＥＭＳセンサを構成する共振周波数調整モジュールであって、
    　移動可能に配設され、移動方向に延在する可動電極と、
    　前記可動電極の前記移動方向に沿って配列する複数の固定電極と、
    　前記可動電極を前記移動方向に移動可能に支持する弾性体とを備え、
    　前記可動電極の前記複数の固定電極との対向面が、前記移動方向に交互に配列する山部及び谷部を有し、
    　前記複数の固定電極の各々が、前記可動電極の１つの山部又は谷部に対向するよう配設される、共振周波数調整モジュール。     A resonance frequency adjustment module constituting a MEMS sensor for detecting angular velocity,
    A movable electrode disposed movably and extending in the direction of movement;
    A plurality of fixed electrodes arranged along the moving direction of the movable electrode;
    An elastic body that supports the movable electrode so as to be movable in the moving direction;
    The opposed surface of the movable electrode to the plurality of fixed electrodes has peaks and valleys that are alternately arranged in the movement direction,
    The resonance frequency adjustment module, wherein each of the plurality of fixed electrodes is disposed so as to face one peak or valley of the movable electrode.
  2. 　前記山部及び前記谷部が略一定のピッチで形成され、
    　前記山部又は前記谷部の平均ピッチと前記複数の固定電極の前記移動方向の平均長さとの差が、前記移動方向における前記可動電極と前記複数の固定電極との間の平均距離の０．５倍以上１．２倍以下である、請求項１に記載の共振周波数調整モジュール。     The peak and the valley are formed at a substantially constant pitch,
    The difference between the average pitch of the peaks or valleys and the average length of the plurality of fixed electrodes in the moving direction is an average distance of 0. 0 to the average distance between the movable electrode and the plurality of fixed electrodes in the moving direction. The resonance frequency adjustment module according to claim 1, wherein the resonance frequency adjustment module is 5 times or more and 1.2 times or less.
  3. 　前記複数の固定電極の各々が、前記可動電極の前記谷部に対向する、請求項１又は２に記載の共振周波数調整モジュール。 The resonance frequency adjustment module according to claim 1 or 2, wherein each of the plurality of fixed electrodes is opposed to the valley portion of the movable electrode.
  4. 　前記可動電極の前記対向面の前記移動方向に対する平均傾斜角が、２度以上１２度以下である、請求項１から３のいずれか１項に記載の共振周波数調整モジュール。 The resonance frequency adjustment module according to any one of claims 1 to 3, wherein an average inclination angle with respect to the moving direction of the facing surface of the movable electrode is 2 degrees or more and 12 degrees or less.
  5. 　請求項１から４のいずれか１項に記載の共振周波数調整モジュールを備える、ＭＥＭＳセンサ。 A MEMS sensor comprising the resonance frequency adjustment module according to any one of claims 1 to 4.
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