JP2006064538A - Gyroscope sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a temperature dependency of detection values in a gyroscope sensor wherein an actuation mass body is vibrated in a direction transverse to a support substrate, and an angular speed value about a prescribed axis line in a plane being perpendicular to a line along the above direction, is detected from a displacement value of a detection mass body in the above plane, which is coupled to the actuation mass body through an actuation spring. <P>SOLUTION: The gyroscope sensor is composed such that the support substrate made of a glass substrate is stacked on one face of a main substrate 1 made up by carving a silicon material, and a cap made of a glass substrate is stacked on the other face, and they are sealed. In the main substrate 1, a pair of actuation mass bodies 11A, 11B are arranged symmetrically on both sides of the detection mass body 12 being centered, and vibrated in phase with each other, thereby suppressing vibrations occurring in the detection mass body 12 in the direction transverse to the support substrate. Furthermore, a pair of detection springs 15 whose base edges are connected to the support substrate, are connected to the center section of the detection mass body 12 at their free edges in order to support them in a cantilevered structure, thereby preventing thermal stresses from existing, even in the case there is a difference of linear expansion coefficient between the main substrate 1 and the support substrate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a gyro sensor using MEMS (Micro Electro Mechanical System) technology.

  In recent years, suspensions and airbag control devices for automobiles, inertial navigation systems for aircraft, camera shake correction devices for cameras, and the like, which are provided with a gyro sensor, have been provided. This type of gyro sensor measures an angular velocity by measuring a Coriolis force when an angular velocity due to an external force acts on a mass body that is applying a prescribed vibration. That is, since the Coriolis force is proportional to the outer product of the angular velocity due to the external force and the velocity of the mass body, a value corresponding to the angular velocity can be obtained from the measured value of the Coriolis force and the known velocity of the mass body.

  As this type of gyro sensor, one produced by a semiconductor manufacturing process using the MEMS technology is known (for example, see Patent Document 1). The gyro sensor (gyroscope) described in Patent Document 1 includes a mass body that is driven to vibrate in a Z direction that is a direction perpendicular to the paper surface, and is an X direction that is one direction (left-right direction) along the paper surface. The angular velocity acting about the axis indicated by the reference symbol R is measured, and as shown in FIG. 6, a rectangular frame-shaped drive mass body (first mass body) 41 and a drive mass body 41 inside A detection mass body (second mass body) 42 to be arranged, and a first spring 43 provided at the center of each side of the drive mass body 41 is fixed to a support substrate (not shown) and extended in the X direction. In addition, each of the left and right sides of the drive mass body 41 and the upper and lower sides of the detection mass body 42 are coupled to each other via four second springs 44.

  Drive electrodes 45 to which a drive voltage is applied are provided on both upper and lower sides of the drive mass body 41 so as to vibrate the drive mass body 41 and the detection mass body 42 supported by the drive mass body 41 in the Z direction. Inside, a horizontal detection electrode 46 for detecting the displacement of the detection mass body 42 in the Y direction by a change in electrostatic capacitance is provided.

  Accordingly, in the state where the drive mass 45 is applied to the drive electrode 45 to vibrate the drive mass body 41 and the detection mass body 42 in the Z direction, if an angular velocity around the X axis R is applied, the drive mass body 41 is moved to the X axis. Displacement around turn R. Since the detection mass body 42 is coupled to the drive mass body 41 via the second spring 44 extended in the X direction, when the drive mass body 41 is displaced about the X axis, the detection mass body 42 is also rotated about the X axis. Displacement to R. Further, since the Coriolis force is generated in the detection mass body 42, the second spring 44 is bent and the detection mass body 42 is displaced in the Y direction. Since the displacement of the detection mass body 42 in the Y direction can be measured by the output of the horizontal detection electrode 46, the Coriolis force is calculated using the vibration in the Z direction applied to the drive mass body 41 and the output of the horizontal detection electrode 46. When the Coriolis force is calculated, a value corresponding to the angular velocity can be obtained.

In addition, another configuration example is described in Patent Document 1, in which the first spring 43 is provided at each corner position of the drive mass body 41, and the second spring 44 is replaced with the first spring 43. A configuration in which the end is fixed to the support substrate and the driving mass body 41 and the detection mass body 42 are connected via the first spring 43 is also disclosed. As an example of the configuration in which one end of the second spring 44 is fixed to the support substrate, the other end of the second spring 44 is connected to the detection mass body 42 and the other end of the second spring 44 is connected to the drive mass body 41. Such a configuration is also disclosed.
JP 2003-194545 A (paragraphs 0014 to 0020 and FIG. 2)

  In the prior art as described above, the drive mass body 41 and the detection mass body 42 are restrained from the four sides by the first spring 43 and the second spring 44, respectively, and the drive mass body 41 and the detection mass body 42 are semiconductors. A glass substrate is generally used as a support substrate to which the first spring 43 and the second spring 44 are joined, whereas the substrate is formed from a substrate. For this reason, thermal stress is generated in the first spring 43 and the second spring 44 due to the difference in linear expansion coefficient between the semiconductor substrate and the glass substrate, and the resonance frequency of the gyro sensor changes. For example, the attachment to the support substrate is performed at 400 ° C., and residual stress is generated even at room temperature. Since the detected value changes when the resonance frequency changes, the gyro sensor according to the conventional technique has a problem that the temperature dependency of the detected value is large.

  The objective of this invention is providing the gyro sensor which can reduce the temperature dependence of a detected value.

  The gyro sensor of the present invention is a gyro sensor comprising a support substrate and a main substrate made of a semiconductor substrate, wherein the main substrate has a base end portion fixed to the support substrate, and an in-plane along the support substrate. Is connected to a pair of detection springs that can be bent and deformed in a direction orthogonal to the one direction, and the free ends of the pair of detection springs, thereby being displaced to the support substrate via the detection spring. A detection mass body that is supported and a pair of the detection mass bodies that are symmetrically arranged on both sides in the one direction and are driven to vibrate in a direction intersecting the support substrate in the same phase. A first drive mass and a second drive mass, a first drive spring and a second drive spring that connect the first drive mass and the second drive mass to the detection mass, respectively, and along the support substrate The detection mass body in the open plane Characterized in that it comprises a detecting means for detecting the amount of displacement.

  According to the above configuration, the detection mass body and the pair of detection springs supporting the first and second drive mass bodies on the support substrate are extended in one direction from the detection mass body, and the detection mass body is cantilevered. Even if there is a difference in the coefficient of linear expansion between the main substrate and the support substrate, almost no thermal stress is generated in the main substrate, so there is almost no change in the resonance frequency, and the temperature dependence of the detected value is reduced. be able to. In addition, the first driving mass body and the second driving mass body are arranged symmetrically on both sides of the detection mass body and are driven in the same phase to cross the support substrate generated in the detection mass body. Vibration in the direction to be performed can be suppressed, and the angular velocity detection accuracy can be improved.

  Moreover, the gyro sensor of the present invention further includes a rigid connecting piece that connects the base ends of the pair of detection springs to each other, and an intermediate portion of the connecting piece is fixed to the support substrate. It is characterized by.

  According to the above configuration, the base ends of the pair of detection springs are not directly fixed to the support substrate, but are connected to each other by a rigid connection piece, and an intermediate portion of the connection piece is fixed to the support substrate. By doing so, the main substrate can be fixed to the support substrate at one place, and the joining operation of the main substrate and the support substrate becomes easy. Further, even if there is a difference in linear expansion coefficient between the main substrate and the support substrate, thermal stress in the extending direction of the connecting piece hardly acts on the detection spring, and the temperature dependence of the detection value can be further reduced. .

  Furthermore, in the gyro sensor of the present invention, the detection spring is connected to the symmetrical line in the detection mass body.

  According to the above configuration, the detection spring is connected to the detection mass body on a line having the first and second drive mass bodies symmetrically with respect to each other, that is, to the center portion of the detection mass body. It is possible to further suppress the vibration in the direction intersecting the support substrate generated in the detection mass body, and further improve the detection accuracy of the angular velocity.

  In the gyro sensor of the present invention, the first drive spring and the second drive spring are torsion springs capable of torsional deformation.

  According to said structure, compared with the spring using a bending deformation, since the space | interval of a 1st and 2nd drive mass body and a detection mass body can be shortened and they can be arrange | positioned in close proximity, space saving is achieved. be able to.

  Furthermore, in the gyro sensor of the present invention, the detection means is disposed inside the cutout hole and a plurality of movable comb teeth protruding from the inner peripheral surface of the cutout hole formed in the detection mass body. And a plurality of fixed comb teeth protruding from the outer peripheral surface of the stator fixed to the support substrate so as to face each movable comb teeth.

  According to the above configuration, since there are a plurality of movable comb teeth pieces and fixed comb tooth pieces, electrostatic capacitance between the movable comb teeth pieces and the fixed comb teeth pieces with respect to the displacement of the detection mass body. The capacity changes relatively greatly, and the accuracy (resolution) for detecting the displacement of the detection mass body can be increased.

  Further, in the gyro sensor of the present invention, in the support substrate, corresponding first and second fixed drive electrodes are respectively disposed on surfaces facing the first and second drive mass bodies, and the support substrate in the detection spring is provided. By applying an oscillating voltage between the fixed portion to the first and second fixed drive electrodes, the first and second drive mass bodies act between the first and second fixed electrodes. The first and second driving mass bodies are vibrated by an electrostatic force.

  According to said structure, the detection spring provided in the main board | substrate, the detection mass body, and the 1st and 2nd drive mass body will be used for an electrical circuit, and a 1st and 2nd fixed drive electrode is used for a support substrate. By simply forming, an oscillating voltage for oscillating the first and second driving mass bodies can be applied, and the structure can be simplified and the size can be reduced.

  Furthermore, in the gyro sensor of the present invention, the support substrate has a plurality of through holes penetrating in the thickness direction, and an inner peripheral surface of the through holes is formed of a conductive metal thin film, and the main substrate is connected to an external circuit. The electrode wiring connected to is formed.

  According to the above configuration, each part of the main substrate can be connected to the external circuit by the electrode wiring formed on the inner peripheral surface of the through hole provided in the support substrate, so that each part of the main substrate can be connected to the external circuit. Therefore, the area occupied by the support substrate can be reduced and the size can be reduced.

  In the gyro sensor of the present invention, the thickness dimension of the first and second drive mass bodies is larger than the thickness dimension of the detection mass body.

  According to said structure, the mass difference of a 1st and 2nd drive mass body and a detection mass body can be enlarged, and the mass of a 1st and 2nd drive mass body is made larger than the mass of a detection mass body. Therefore, the sensitivity can be increased.

  Furthermore, the gyro sensor of the present invention vibrates the driving mass body in a direction intersecting the support substrate, and what is the vibration direction of the driving mass body in the detection mass body connected to the driving mass body via a driving spring? In the gyro sensor configured to detect an angular velocity around a predetermined axis in the plane by detecting a displacement amount in a vertical plane, the drive mass bodies are arranged on both sides of the detection mass body as a center. A pair of symmetrically arranged and oscillating in the same phase with each other, extending in parallel with the arrangement direction of the driving mass body and the detection mass body, the base end portion is connected to the support substrate, and the free end portion is the detection mass A pair of detection springs that support displacement of the drive mass body and the detection mass body in the vibration direction and displacement in a direction perpendicular thereto by being connected to a body, and displacement in the surface direction of the detection mass body amount Characterized in that it comprises a detection means for detecting for.

  According to the above configuration, the pair of detection springs that support the detection mass body and the two driving mass bodies connected thereto on the support substrate are extended in one direction from the detection mass body, and cantilevered in the detection mass body Even if there is a difference in coefficient of linear expansion between the main substrate on which the drive mass body, the drive spring, the detection mass body and the detection spring are formed, and the support substrate, there is almost no thermal stress on the main substrate. Since it does not occur, there is almost no change in the resonance frequency, and the temperature dependence of the detected value can be reduced. In addition, by arranging two driving mass bodies symmetrically on both sides of the detection mass body and driving them in the same phase, vibration in the direction intersecting the support substrate generated in the detection mass body is suppressed. It is possible to improve the angular velocity detection accuracy.

  As described above, the gyro sensor of the present invention is a gyro sensor comprising a support substrate and a main substrate made of a semiconductor substrate. The gyro sensor includes a base end portion fixed to the support substrate, and the support substrate. Are connected to a pair of detection springs that extend in one direction within the plane along the direction and can be bent and deformed in a direction orthogonal to the one direction, and free ends of the pair of detection springs. The detection mass body that is displaceably supported by the support substrate and the detection mass body are arranged symmetrically with respect to both sides of the detection mass body so as to vibrate in a direction intersecting the support substrate in the same phase. A pair of first and second drive masses to be driven, a first drive spring and a second drive spring coupling the first and second drive masses to the detection mass, respectively; In-plane along the support substrate Configuring and a detection means for detecting a displacement amount of the serial detection mass body.

  Therefore, the pair of detection springs supporting the detection mass body and the first and second drive mass bodies on the support substrate are extended in one direction from the detection mass body and support the detection mass body in a cantilever manner. Even if there is a difference in the linear expansion coefficient between the main substrate and the support substrate, almost no thermal stress is generated in the main substrate, so that there is almost no change in the resonance frequency, and the temperature dependence of the detected value can be reduced. In addition, the first driving mass body and the second driving mass body are arranged symmetrically on both sides of the detection mass body and are driven in the same phase to cross the support substrate generated in the detection mass body. Vibration in the direction to be performed can be suppressed, and the angular velocity detection accuracy can be improved.

  FIG. 1 is a longitudinal sectional view showing a structure of a gyro sensor according to an embodiment of the present invention. In this gyro sensor, a main substrate 1 made of a silicon substrate is roughly carved into a shape as will be described later by etching or the like, and a support substrate 2 made of a glass substrate is laminated on one surface, and the other surface is made. The support substrate 2 and the cap 3 are bonded to the main substrate 1 by, for example, anodic bonding. Note that a semiconductor other than silicon can be used for the main substrate 1.

  FIG. 2 is a plan view of the main substrate 1. In FIG. 2, the cut surface of FIG. 1 is indicated by II. The main substrate 1 includes a first driving mass body 11A and a second driving mass body 11B that are rectangular in a plan view, and a detection mass body 12 arranged in parallel along the plate surface of the main substrate 1, The first driving mass body 11 </ b> A, the second driving mass body 11 </ b> B, and the detection mass body 12 are configured to include a rectangular frame 10 surrounding the periphery. Therefore, in a state where the support substrate 2 and the cap 3 are joined to the main substrate 1, the first drive mass body 11A, the second drive mass body 11B, and the detection are in the space surrounded by the support substrate 2, the cap 3 and the frame 10. The mass body 12 is sealed. In the following, the direction in which the first driving mass body 11A, the detection mass body 12 and the second driving mass body 11B are arranged is the Y direction, and the direction orthogonal to the Y direction in the plane along the plate surface of the main substrate 1 is the X direction. A direction perpendicular to the direction and the Y direction, that is, a direction perpendicular to the plate surface of the main substrate I (a direction perpendicular to the paper surface) is defined as a Z direction.

  The detection mass body 12 includes a pair of first drive springs 13A extended in the X direction so that the positions and shapes of the first drive mass body 11A and the second drive mass body 11B are axisymmetric. The first driving mass body 11A and the second driving mass body 11B are connected to the continuous body via the second driving spring 13B and the second driving spring 13B, respectively. Specifically, the detection mass body 12 is formed with a slit groove 14A slightly shorter than the entire length in the X direction, leaving both side edges, and the first driving mass body 11A and the second driving mass body 11B have Are formed by two slit grooves 14B cut from the respective side edges in the X direction and aligned with each other, and the first drive springs 13A are respectively provided between the slit grooves 14A and the respective slit grooves 14B. And the 2nd drive spring 13B is formed. The negative ends of the drive springs 13A and 13B are continuous between the end portions of the slit groove 14A and the side edges of the detection mass body 12, and the other ends of the drive springs 13A and 13B are two slits. The first driving mass body 11A and the second driving mass body 11B are respectively connected to the portions between the grooves 14B.

  The first drive spring 13 </ b> A and the second drive spring 13 </ b> B are torsion springs that can be torsionally deformed, and the first drive mass 11 </ b> A and the second drive mass 11 </ b> B are the first drive spring 13 </ b> A with respect to the detection mass 12. The second drive spring 13B can be displaced. That is, it can be said that the first driving mass body 11A and the second driving mass body 11B can translate in the Z direction and rotate around the axis in the X direction with respect to the detection mass body 12. Further, since the torsion springs are used for the first drive spring 13A and the second drive spring 13B, it is necessary to reduce the thickness of the first drive spring 13A and the second drive spring 13B unnecessarily in order to obtain a desired small spring coefficient. There is no, and the process at the time of forming the 1st drive spring 13A and the 2nd drive spring 13B is easy.

  In addition, the slit groove 14A may be formed in the first driving mass body 11A and the second driving mass body 11B, and the two slit grooves 14B may be formed in the detection mass body 12.

  At each side edge of the detection mass body 12 in the X direction, the free end portions of the detection springs 15 extending in the Y direction are respectively positioned in line symmetry with the first drive mass body 11A and the second drive mass body 11B. The base ends of the two detection springs 15 are continuously connected to each other via a connecting piece 16 extending in the X direction. That is, the pair of detection springs 15 and the connecting piece 16 form a U-shaped member in plan view. However, the connecting piece 16 is designed to have sufficiently high rigidity as compared with the first drive spring 13A, the second drive spring 13B, and the detection spring 15. A fixing piece 17 projects from an intermediate portion in the longitudinal direction of the connecting piece 16, and the fixing piece 17 is joined to the support substrate 2 and fixed at a fixed position. The first drive mass body 11A and the detection mass body 12, and the detection spring 15 and the connecting piece 16 are separated by a U-shaped slit groove 14C, and a slit groove formed in the first drive mass body 11A. One end of 14B continues to the slit groove 14C. The detection spring 15 can be bent and deformed in the X direction, and the first drive mass body 11A, the second drive mass body 11B, and the detection mass body 12 can be displaced in the X direction with respect to the fixed piece 17. Yes.

  The detection mass body 12 also has four cutout holes 18 penetrating in the thickness direction, and a stator 20 is disposed inside each cutout hole 18. The stator 20 has electrode pieces 21 arranged in the vicinity of both ends in the X direction of the detection mass body 12, and a comb piece 22 extends in the X direction from the electrode pieces 21. The electrode piece 21 and the comb piece 22 are joined to the support substrate 2, and the stator 20 is fixed in place. The inner peripheral surface of the cutout hole 18 has a shape that follows the shape of the outer peripheral surface of the stator 20, and a gap is formed between the cutout hole 18 and the stator 20. Two electrode pieces 21 are arranged at both ends of the detection mass body 12 in the X direction, but may be one piece or three pieces. As shown in FIG. 3, a large number of fixed comb teeth 23 are arranged in the X direction on both end faces in the width direction of the comb bone piece 22. On the other hand, on the inner surface of the cut-out hole 18 and the surface facing the comb bone piece 22, a plurality of movable comb teeth 24 respectively facing the fixed comb teeth 23 are arranged in the X direction. Each fixed comb tooth piece 23 and each movable comb tooth piece 24 are arranged so as to be separated from each other, and the fixed comb tooth piece 23 and the movable comb tooth piece 24 when the detection mass body 12 is displaced around the Y axis R. It is possible to detect a change in electrostatic capacitance accompanying a change in the distance in the X direction. That is, the fixed comb tooth piece 23 and the movable comb tooth piece 24 constitute a mountain detecting means for detecting the displacement of the detection mass body 12.

  The support substrate 2 and the cap 3 are joined to the frame 10 left on the outer peripheral portion of the main substrate 1, and the fixing piece 17 and the stator 20 are joined to the support substrate 2. However, since the first drive mass body 11A, the second drive mass body 11B, and the detection mass body 12 must be displaceable in the Z direction in the gap formed between the support substrate 2 and the cap 3, FIG. As shown, the support substrate 2 and the first drive mass body are moved back by moving the opposing surfaces of the first drive mass body 11A, the second drive mass body 11B and the detection mass body 12 to the support substrate 2 from the support substrate 2. 11A, a gap g1 between the second drive mass body 11B and the detection mass body 12 is secured, and a recess 29 is formed on the surface of the cap 3 that faces the main substrate 1, whereby the cap 3 and the first drive A gap g2 is secured between the mass body 11A, the second drive mass body 11B, and the detection mass body 12.

  Both gaps g1 and g2 are several μm to several tens of μm, and are set to 10 μm, for example. In this case, the thickness dimension t1 of the fixed piece 17 is set to 300 μm, and the thickness dimension t2 of the first driving mass body 11A and the second driving mass body 11B is set to 290 μm. Instead of changing the thickness dimension of the main substrate 1, a recess may be formed in a portion of the support substrate 2 that faces the first driving mass body 11 </ b> A, the second driving mass body 11 </ b> B, and the detection mass body 12. . In short, the first drive mass body 11A, the second drive mass body 11B, and the support substrate 2 are provided so that the gap g1 can be secured on the opposing surfaces of the first drive mass body 11A and the second drive mass body 11B and the support substrate 2. And at least one of them may be made to recede from the other.

  In the support substrate 2, the first fixed drive electrode 25 </ b> A and the second fixed drive electrode 25 </ b> B made of a conductive metal thin film such as aluminum are provided on the surface facing the first drive mass body 11 </ b> A and the second drive mass body 11 </ b> B. Is formed. Further, from the outer surface of the support substrate 2, a portion corresponding to the fixed piece 17, a portion corresponding to each electrode piece 21 of the stator 20, and the first fixed drive electrode 25 </ b> A and the second fixed drive electrode 25 </ b> B. Through holes 26 as shown in FIG. 4 are formed in corresponding portions. Further, in the illustrated example, a pair of grounding pieces 19 are formed in the frame 10 in the vicinity of the mounting pieces 17 so as to sandwich the mounting pieces 17, and the through-holes 26 are also formed at portions corresponding to the respective grounding pieces 19. It is formed.

  As shown in FIG. 4, an electrode wiring 27 made of a conductive metal thin film such as aluminum is formed in the through hole 26. The through hole 26 is tapered so that the inner diameter decreases as it approaches the main substrate 1, and the electrode wiring 27 is formed so as to cover not only the inner peripheral surface of the through hole 26 but also a part of the surface of the main substrate 1. Yes. That is, one end surface of the through hole 26 is blocked by the electrode wiring 27, and the electrode wiring 27 is electrically connected to each of the above-described portions of the main substrate 1. A part of the electrode wiring 27 can be extended to the surface of the support substrate 2 (the surface opposite to the main substrate 1 in the thickness direction), and the portion extended to the surface of the support substrate 2 functions as an electrode pad 28. Thus, by forming the electrode wiring 27 of the metal thin film similar to the through-hole plating on the inner peripheral surface of the through hole 26 formed in the support substrate 2, each member formed on the main substrate 1 and the electrode pad 28 are supported. Since the connection is made in the thickness direction of the substrate 2, it is possible to connect to an external circuit without routing the wiring on the main substrate 1, and a reduction in the substrate area can be realized.

  When the gyro sensor configured as described above is manufactured, the main substrate 1 is bonded to the support substrate 2 in which the through holes 26 are formed. In this state, each part (the frame 10, the first driving mass body 11A, the second driving mass body 11B, the detection mass body 12 and the stator 20) of the main board 1 is not separated, and the main board 1 is supported by the supporting board. After joining to 2, grooves for separating the frame 10, slit structures 14 </ b> A to 14 </ b> C, and grooves for separating the stator 20 are formed from the surface facing the cap 3 in the main substrate 1 and separated into each part. At this stage, since the fixed piece 17 is joined to the support substrate 2, the connecting piece 16, the detection spring 15, the detection mass body 12, the first driving mass body 11A, and the second driving mass body 11B that are continuous to the fixing piece 17 are used. Is held on the support substrate 2, and the stator 20 is also bonded to the support substrate 2. Thereafter, if the cap 3 is joined to the main substrate 1, the first driving mass body 11 </ b> A, the second driving mass body 11 </ b> B, and the detection mass body 12 are in a space surrounded by the support substrate 2, the cap 3, and the frame 10. Sealed. Furthermore, by forming the electrode wiring 27 in the through hole 26 of the support substrate 2 and forming the electrode pad 28, the above-described gyro sensor is formed.

  The operation of this embodiment will be described below. The gyro sensor of the present embodiment detects when the angular velocity around the axis in the Y direction by an external force is applied to the first driving mass body 11A and the second driving mass body 11B by applying predetermined in-phase vibrations. The displacement of the mass body 12 is detected. In order to vibrate the first drive mass body 11A and the second drive mass body 11B in the same phase, the first fixed drive electrode 25A and the second fixed drive electrode 25B, and the first drive mass body 11A and the second drive mass body 11B Between them, an oscillating voltage having a sine waveform or rectangular waveform having the same phase may be applied. The oscillating voltage is preferably an AC waveform, but it is not essential to reverse the polarity.

  The first driving mass body 11A and the second driving mass body 11B are electrically connected to the fixed piece 17 via the springs 13A, 13B—the detection mass body 12—the detection spring 15—the connecting piece 16, and in the support substrate 2. A through hole 26 is formed in a portion corresponding to the fixed piece 17, and a through hole 26 is also formed in a portion corresponding to the first fixed drive electrode 25A and the second fixed drive electrode 25B. Therefore, if an oscillating voltage is applied to the electrode wiring 27 corresponding to both the through holes 26, the first driving mass body 11A and the second driving mass body 11B and the first fixed driving electrode 25A and the second fixed driving electrode 25B In the meantime, the first driving mass 11 </ b> A and the second driving mass 11 </ b> B can be vibrated in the Z direction with respect to the support substrate 2 and the cap 3 by applying an electrostatic force. The frequency of the oscillating voltage is determined by the masses of the first drive mass body 11A, the second drive mass body 11B, and the detection mass body 12, the spring constants of the first drive spring 13A, the second drive spring 13B, and the detection spring 15, and the like. A large amplitude can be obtained with a relatively small driving force.

  Thus, when the first driving mass body 11A and the second driving mass body 11B are vibrated in the same phase, when an angular velocity around the axis in the Y direction acts on the main substrate 1, a Coriolis force is generated in the X direction. The first driving mass body 11 </ b> A, the second driving mass body 11 </ b> B, and the detection mass body 12 are displaced in the X direction with respect to the stator 20. Thus, if the movable comb tooth piece 24 is displaced with respect to the fixed comb tooth piece 23, the distance between them changes, and as a result, the electrostatic comb between the movable comb tooth piece 24 and the fixed comb tooth piece 23 changes. The capacity changes. This change in capacitance can be taken out from the electrode wiring 27 connected to the four stators 20.

  That is, the capacitance between each pair of electrode pieces 21 arranged in the X direction reflects the change in the distance between the fixed comb-tooth piece 23 and the movable comb-tooth piece 24, so that both electrode pieces 21 are variable capacitance capacitors. It is equivalent to an electrode, and in the configuration shown in the figure, two variable capacitors are formed, so the capacitance of each variable capacitor is detected individually, or the combined capacitance in which both variable capacitors are connected in parallel is detected. By doing so, the displacement of the detection mass body 12 can be detected. Since the vibrations of the first driving mass body 11A and the second driving mass body 11B are known, the Coriolis force can be obtained by detecting the displacement of the detection mass body 12.

  Here, the displacement of the movable comb tooth piece 24 is (mass of the first driving mass body 11A + mass of the second driving mass body 11B) / (mass of the first driving mass body 11A + mass of the second driving mass body 11B). + The mass of the detection mass body 12), the larger the mass of the first drive mass body 11A + the mass of the second drive mass body 11B compared to the mass of the detection mass body 12, the more the movable comb tooth piece 24 has. The displacement increases, and as a result, the sensitivity is improved. Therefore, in the present embodiment, the thickness dimension of the first drive mass body 11A and the second drive mass body 11B is set to be approximately twice the thickness dimension of the detection mass body 12. For example, when the thickness t2 (see FIG. 4) of the first drive mass 11A and the second drive mass 11B is set to 290 μm as described above, the thickness of the detection mass 12 is set to about 150 μm. Is desirable. When comprised in this way, it can detect with the resolution of 0.1 degrees / sec in the detection range of the angular velocity of 1-100 degrees / sec.

  As is clear from the dimensional relationship described above, the thickness dimension of the support substrate 2 is constant in order to allow the first driving mass body 11A, the second driving mass body 11B, and the detection mass body 12 to be displaced in the Z direction. In some cases, the thickness dimension of the main substrate 1 may be set in two stages different between the frame 10, the fixed piece 17 and the stator 20, and other parts, and the thickness dimension of the detection mass body 12 is set to the first drive. When the thickness is smaller than the thickness of the mass body 11A and the second drive mass body 11B, the thickness of the main substrate 1 is set to the frame 10, the fixed piece 17, the stator 20, the detection mass body 12, and other parts. What is necessary is just to make three steps which are different. In the case where the thickness dimension of the support substrate 2 is set to two stages that are different between the joint portion between the fixed piece 17 and the stator 20 and other portions, the thickness dimension of the main substrate 1 is set to the frame 10 and the first drive. The mass body 11A, the second drive mass body 11B, the connecting piece 16, the fixed piece 17, and the stator 20 may be two stages different from each other. With this configuration, the first driving mass body 11A, the second driving mass body 11B, and the detection mass body 12 can have different thickness dimensions.

  In the configuration described above, the fixed piece 17 is provided at one place in the middle portion of the connecting piece 16 in the longitudinal direction. However, in the present invention, the first drive mass body 11A, the second drive mass body 11B, and the detection mass body 12 are provided. The first drive mass body 11A and the second drive mass body 11B can be displaced relative to the detection mass body 12 by being connected via the first drive spring 13A and the second drive spring 13B which are torsion springs. If the detection spring 15 that supports the detection mass body 12 so as to be displaceable with respect to the support substrate 2 is cantilevered, the object can be achieved. Therefore, as shown in FIG. 5, the fixed piece 17 may be provided continuously at one end of each detection spring 15 without providing the connecting piece 16. In this configuration, even if a thermal stress is generated due to a difference in linear expansion coefficient between the main substrate 1 and the support substrate 2, only the thermal stress in the X direction in the bending direction of the detection spring 15 is obtained. Since no thermal stress is generated in the Y direction, which is the compression / extension direction, the resonance frequency hardly changes. That is, it is possible to reduce a change in detection accuracy due to a temperature change. In order to reduce the influence of thermal stress in the X direction, it is desirable to form the detection spring 15 so as to reduce the spring constant in the X direction.

  In the configuration example described above, the Coriolis force in the X direction due to the action of the angular velocity R around the axis in the Y direction is measured while the first driving mass body 11A and the second driving mass body 11B are vibrated in the Z direction. The first driving mass body 11A and the second driving mass body 11B are translated in the Z direction, and the detection mass body 12 is rotationally moved around the axis in the Y direction and translated in the X direction. However, the first drive mass body 11A and the second drive mass body 11B adopt a configuration in which the rotation movement or the rotation movement and the translation movement are performed, or the detection mass body 12 performs only one of the rotation movement and the translation movement. It is also possible to adopt a configuration to be performed, and the moving directions of the first driving mass body 11A, the second driving mass body 11B, and the detection mass body 12 are not particularly limited.

  As described above, in the gyro sensor of the present invention, the pair of detection springs 15 that support the detection mass body 12, the first drive mass body 11 </ b> A, and the second drive mass body 11 </ b> B on the support substrate 2 are the detection mass body 12. Is extended in one direction and supports the detection mass body 12 in a cantilever manner, and even if there is a difference in the linear expansion coefficient between the main substrate 1 and the support substrate 2, almost no thermal stress is generated in the main substrate 1. Therefore, there is almost no change in the resonance frequency, and the temperature dependence of the detected value can be reduced. Further, the first driving mass body 11A and the second driving mass body 11B are arranged symmetrically on both sides of the detection mass body 12 and driven in the same phase to generate the detection mass body 12. It is possible to suppress the vibration in the direction intersecting the support substrate 2 and improve the detection accuracy of the angular velocity.

  In the gyro sensor of the present invention, the base end portions of the pair of detection springs 15 are not directly fixed to the support substrate 2, but are connected to each other by a connecting piece 16 having rigidity, and an intermediate portion of the connecting pieces. Since the fixing piece 17 provided in the portion is fixed to the support substrate 2, the main substrate 1 can be fixed to the support substrate 2 at one place, and the joining operation of the main substrate 1 and the support substrate 2 becomes easy. . Further, even if there is a difference in the linear expansion coefficient between the main substrate 1 and the support substrate 2, thermal stress in the extending direction of the connecting piece 16 hardly acts on the detection spring 15, and the temperature dependence of the detection value is further reduced. can do.

  Furthermore, in the gyro sensor of the present invention, the detection spring 15 is arranged on a line where the first drive mass body and the second drive mass body are symmetrical with each other in the detection mass body 12, that is, the detection mass body. Therefore, the vibration in the direction intersecting the support substrate 2 generated in the detection mass body 12 can be further suppressed, and the angular velocity detection accuracy can be further improved.

  In the gyro sensor of the present invention, since the first drive spring 13A and the second drive spring 13B are torsion springs that can be torsionally deformed, the first drive mass body 11A is compared with a spring that utilizes flexural deformation. And since the space | interval of the 2nd drive mass body 11B and the detection mass body 12 can be shortened and they can be arrange | positioned closely, space saving can be achieved. Moreover, linearity is also favorable.

  Furthermore, in the gyro sensor of the present invention, the detection means includes a large number of movable comb teeth 24 projecting from the inner peripheral surface of the cutout hole 18 formed in the detection mass body 12, and the inside of the cutout hole 18. And a plurality of fixed comb teeth 23 projecting on the outer peripheral surface of the stator 20 fixed to the support substrate 2 so as to face the movable comb teeth 24, respectively. The capacitance between the movable comb tooth piece 24 and the fixed comb tooth piece 23 changes relatively greatly with respect to the displacement of the mass body 12, and the accuracy (resolution) for detecting the displacement of the detection mass body 12 is improved. Can be increased.

  In the gyro sensor of the present invention, the first fixed drive electrode 25A and the second fixed drive electrode corresponding to the surfaces of the support substrate 2 facing the first drive mass body 11A and the second drive mass body 11B, respectively. 25B is arranged, and an oscillating voltage is applied between the detection spring 15 fixed to the support substrate 2 and the first and second fixed drive electrodes, whereby the first drive mass 11A and second Since the first driving mass body 11A and the second driving mass body 11B are vibrated by an electrostatic force acting between the driving mass body 11B and the first fixed electrode 25A and the second fixed electrode 25B, the main board 1 is provided. The detection spring 15, the detection mass body 12, and the first and second drive mass bodies 11 </ b> A and 11 </ b> B are used for the electric circuit, and the first and second fixed drive electrodes 25 </ b> A and 25 are provided on the support substrate 2. Only form the first and second driving masses 11A, it is possible to apply an oscillating voltage for vibrating the 11B, to simplify the structure, it can be reduced in size.

  Furthermore, in the gyro sensor of the present invention, the support substrate 2 has a plurality of through holes 26 penetrating in the thickness direction, and the inner peripheral surface of the through hole 26 is made of a conductive metal thin film, Since the electrode wiring 27 for connecting 1 to the external circuit is formed, it is not necessary to route the wiring for connecting each part of the main substrate 1 to the external circuit, and as a result, the occupied area of the support substrate 2 is reduced. And miniaturization can be achieved.

It is a longitudinal cross-sectional view which shows the structure of the gyro sensor which concerns on one Embodiment of this invention. It is a top view of the main board | substrate in the gyro sensor shown in FIG. It is a principal part top view which shows the main board | substrate used for embodiment of this invention. It is principal part side surface sectional drawing which shows embodiment of this invention. It is a top view which shows the main board | substrate used for other embodiment of this invention. It is a top view which shows a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main board 2 Support board 3 Cap 10 Frame 11A 1st drive mass body 11B 2nd drive mass body 12 Detection mass body 13A 1st drive spring 13B 2nd drive spring 14A, 14B Slit groove 15 Detection spring 16 Connection piece 17 Fixing piece 18 Cutout hole 20 Stator 21 Electrode piece 23 Fixed comb tooth piece 24 Movable comb tooth piece 25A First fixed drive electrode 25B Second fixed drive electrode 26 Through hole 27 Electrode wiring

Claims (9)

In a gyro sensor comprising a support substrate and a main substrate made of a semiconductor substrate, the main substrate is
A pair of detection springs having a base end portion fixed to the support substrate, extending in one direction within a plane along the support substrate, and capable of bending and deforming in a direction orthogonal to the one direction;
A detection mass body that is connected to a free end portion of the pair of detection springs and is displaceably supported by a support substrate via the detection springs,
A pair of first and second driving masses that are symmetrically arranged on both sides of the one direction of the detection mass body and are driven to vibrate in a direction intersecting the support substrate in the same phase. Body,
A first drive spring and a second drive spring coupling the first drive mass and the second drive mass to the detection mass, respectively;
A gyro sensor comprising: detecting means for detecting a displacement amount of the detection mass body in a plane along the support substrate.   The base end portions of the pair of detection springs are connected to each other and further have a rigid connecting piece, and an intermediate portion of the connecting piece is fixed to the support substrate. Gyro sensor.   The gyro sensor according to claim 1, wherein the detection spring is connected to the symmetric line in the detection mass body.   The gyro sensor according to any one of claims 1 to 3, wherein the first drive spring and the second drive spring are torsion springs capable of torsional deformation.   The detection means includes a plurality of movable comb teeth protruding from the inner peripheral surface of the cutout hole formed in the detection mass body, and a stator disposed on the inner side of the cutout hole and fixed to the support substrate. 5. The gyro sensor according to claim 1, comprising a plurality of fixed comb teeth protruding from the outer circumferential surface of the movable comb teeth so as to face each movable comb teeth.   In the support substrate, corresponding first and second fixed drive electrodes are respectively disposed on opposing surfaces of the first and second drive mass bodies, and a fixing portion to the support substrate in the detection spring, and the first By applying an oscillating voltage between the first and second fixed drive electrodes, the first and second electrostatic forces acting between the first and second drive mass bodies and the first and second fixed electrodes are applied. The gyro sensor according to claim 1, wherein the drive mass body is vibrated.   The support substrate has a plurality of through holes penetrating in the thickness direction, and an inner peripheral surface of the through hole is formed of a conductive metal thin film, and electrode wiring for connecting the main substrate to an external circuit is formed. The gyro sensor according to claim 1, wherein:   The gyro sensor according to any one of claims 1 to 7, wherein a thickness dimension of the first and second drive mass bodies is larger than a thickness dimension of the detection mass body. The drive mass body is vibrated in a direction intersecting the support substrate, and a displacement amount in a plane perpendicular to the vibration direction of the drive mass body is detected in the detection mass body connected to the drive mass body via a drive spring. In the gyro sensor that detects the angular velocity around the predetermined axis in the plane,
Centering on the detection mass body, the drive mass bodies are arranged symmetrically in pairs on both sides thereof, and vibrate in phase with each other,
The drive mass body and the detection mass body extend in parallel with the arrangement direction of the drive mass body and the detection mass body, the base end portion is connected to the support substrate, and the free end portion is connected to the detection mass body. A pair of detection springs that support the displacement in the vibration direction and the displacement in the direction perpendicular thereto,
A gyro sensor comprising: detecting means for detecting a displacement amount of the detection mass body in the surface direction.

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