JP2008058259A - Inertial sensor and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the sensitivity of angular velocity detection, as well as, to remove errors that are due to the influence of external acceleration, in the output of an angular velocity sensor. <P>SOLUTION: In an inertial sensor 1, where a plurality of inertial sensor elements 2, 3 which use an electromagnetic drive system and an electrostatic detection system and detect two-axis direction angular velocities by drive vibration in one direction of an axis from among three axes that are mutually orthogonal, are formed on the same substrate (first substrate 100), at least one set of the sensor elements 2, 3 is arranged in directions that are mutually orthogonal on the first substrate 100. The plurality of sensor elements 2, 3 are supported by a plurality of elastic supports 102-1 to 102-6, and are equipped with two pairs of vibrators (first vibrator 101-1 and second vibrator 101-2), having vibration modes that drive and vibrate with phases that are mutually opposite. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an inertial sensor having a vibrator for detecting angular velocity and acceleration, and a method for manufacturing the same.

  A sensor structure that detects angular velocity and acceleration in multi-axis directions by combining a plurality of sensor chips has been proposed.

  For example, there is a configuration in which a first element and a second element are installed on a substrate in order to detect angular velocities around three axes. In this configuration, since the mass portion of the first element is vibrated in the X direction, when the angular velocity around the Z axis acts, the vibration around the Z axis can be detected by detecting the vibration caused by the Coriolis force acting in the Y direction. Angular velocity can be detected. Further, since the mass portion of the second element is vibrated in the Z-axis direction, the angular velocity around the X axis is detected by detecting the vibration caused by the Coriolis force acting in the Y direction when the angular velocity around the X axis acts. Can be detected. Similarly, the angular velocity around the Y axis can be detected by detecting the vibration caused by the Coriolis force acting in the X direction when the angular velocity around the Y axis acts. The angular velocity sensor supports one vibrator with four elastic supports, and uses a comb-shaped electrode for driving or detecting in the X direction or Y direction, and a flat electrostatic electrode for driving or detecting in the Z direction. (For example, refer to Patent Document 1).

  In the above prior art, two elements (a uniaxial angular velocity sensor chip and a biaxial angular velocity sensor chip) are mounted on a substrate in order to detect angular velocities around three axes. In the angular velocity sensor chip structure, one vibrator is supported by four elastic supports. A comb-shaped electrode is used for driving or detecting in the X-axis direction or the Y-axis direction, and a flat electrostatic electrode is used for driving or detecting in the Z-axis direction. Is used. In this structure, for example, in the first element, since the mass portion is vibrated in the X-axis direction, when the angular velocity around the Z-axis acts, the vibration due to the Coriolis force acting in the Y-axis direction is detected. The angular velocity around the Z axis can be detected. However, when an acceleration having a component in the Y-axis direction or the Y-axis direction (referred to as external acceleration) is applied, the mass part is displaced in the Y-axis direction even though no angular velocity is applied to the mass part. A capacitance change occurs in the electrode, and a signal is output as if an angular velocity is applied.

  Thus, there is a problem that an error occurs in the angular velocity sensor output due to the influence of the external acceleration.

  Since the second element has a structure in which one mass part is supported by a plurality of elastic supports like the first element, there is a problem that an error occurs in the angular velocity sensor output due to the influence of external acceleration.

When the angular velocity is applied to the angular velocity sensor, a Coriolis force is generated. The Coriolis force F _coriolis is _expressed by the following equation.

F _coriolis = 2mvΩ

  Here, m is the mass of the vibrator, v is the vibration velocity in the driving direction, and Ω is the angular velocity applied from the outside.

In order to increase the displacement generated by the Coriolis force, it is necessary to increase the mass m, the driving angular frequency ωx, and the driving displacement xm ₍ ωx _and xm _{are corresponding parameters of the driving vibration speed v)} . However, in the case of an electrostatic drive and electrostatic detection angular velocity sensor using a comb-shaped electrode, a large displacement cannot be obtained due to the structure of the comb-shaped electrode, and thus there is a limit in improving the angular velocity detection sensitivity.

  Further, when detecting angular velocities around two axes around the X axis and the Y axis by driving in the Z-axis direction like the first element, in order to increase the angular velocity detection sensitivity, the gap between the comb electrodes is narrowed. Alternatively, it is conceivable to make the mass part heavy, but it is difficult to make the mass part heavy while narrowing the gap of the comb-shaped electrode in terms of the production of the detection electrode (usually using a deep silicon etching technique). Therefore, it is difficult to increase the sensitivity of angular velocity detection with the prior art.

JP-A-11-295075

  The problem to be solved is that an error occurs in the output of the angular velocity sensor due to the influence of external acceleration. In the case of the angular velocity sensor of electrostatic drive and electrostatic detection, the displacement of the comb-shaped electrode cannot take a large displacement. There is a limit in improving detection sensitivity.

  It is an object of the present invention to eliminate an error in the angular velocity sensor output due to the influence of external acceleration and to increase the sensitivity of angular velocity detection.

  The inertial sensor of the present invention uses an electromagnetic drive method and an electrostatic detection method, and a plurality of inertial sensor elements that detect angular velocities in two axial directions by driving vibration in one axial direction among three axes orthogonal to each other on the same substrate. The inertial sensor element is formed such that at least one inertial sensor element of the inertial sensor element is arranged in a direction orthogonal to each other on the substrate, and the inertial sensor element is supported by a plurality of elastic supports, An electrostatic detection electrode provided with two pairs of vibrators having vibration modes that vibrate in opposite phases to each other, and a displacement due to the Coriolis force of each vibrator is provided at a position facing each vibrator and each vibrator. It is characterized by detecting by the difference in capacitance change.

  The inertial sensor of the present invention is an electrostatic detection system, and is supported by a plurality of elastic supports, and includes two pairs of vibrators having vibration modes that are driven and oscillated in opposite phases. The vibrator is driven in a vibration mode that vibrates in the opposite phase, and the displacement of the vibrator due to the Coriolis force is detected by the difference in capacitance change between the electrostatic electrode and the two pairs of vibrators forming the electrostatic detection method. From this, when the angular velocity is applied, the capacitance change amount generated between each electrode and the vibrator is different, and when the translational acceleration is applied, the generated capacitance change amount is not different. However, there is no difference in capacity. Therefore, even if external acceleration is applied during application of the angular velocity, the translational acceleration can be removed, so that the sensitivity of detecting the angular velocity is improved. In addition, by adopting the electromagnetic driving method, the driving method of the vibrator can be increased as compared with the electrostatic driving method using the comb-shaped electrode, so that the detection sensitivity of the angular velocity is further improved.

  The inertial sensor manufacturing method of the present invention uses an electromagnetic drive method and an electrostatic detection method, and uses a plurality of inertial sensor elements that detect angular velocities in two axial directions by driving vibration in one axial direction among three orthogonal axes. A method of manufacturing an inertial sensor formed on a substrate, wherein at least one set of inertial sensor elements of the inertial sensor elements is arranged in a direction orthogonal to each other on the substrate, and the inertial sensor elements are formed on the same substrate in the same process. It is formed on the top.

  In the inertia sensor manufacturing method of the present invention, the same components of each inertial sensor element can be formed in the same mask. Therefore, the detection axes of the inertial sensor elements can be perfectly aligned.

  According to the inertial sensor of the present invention, a biaxial angular velocity sensor or a triaxial angular velocity sensor can be provided without being affected by external acceleration, and since an electromagnetic driving method is used, a large driving vibration amplitude can be obtained. There is an advantage that the detection sensitivity can be improved.

  According to the inertial sensor manufacturing method of the present invention, since the detection axes of the inertial sensor elements can be perfectly aligned, the shift of the detection axes between the inertial sensor elements can be eliminated, so that highly sensitive angular velocity detection is possible. There is an advantage of becoming.

  FIG. 1 is a plan layout diagram of (1) showing the inertial sensor of FIG. 1 and a schematic cross-sectional view showing the configuration position of the detection electrode of (2); 2 is a plane layout diagram showing the inertial sensor element of FIG. 2, a plane layout diagram showing electrodes of the inertial sensor element of FIG. 3, a sectional view taken along the line AA ′ of the inertial sensor element of FIG. 4, and an inertial sensor element of FIG. BB 'line sectional drawing of FIG. 6, and the CC' line sectional drawing of the inertial sensor element of FIG.

  As shown in FIG. 1, an inertial sensor 1 of the present invention detects angular velocity in two axial directions by driving vibration in one axial direction among three axes orthogonal to each other, and uses an electromagnetic driving method and an electrostatic detection method. The plurality of inertial sensor elements 2 and 3 formed on the same substrate 10 (for example, a first substrate 100 described later). The inertial sensor elements 2 and 3 are supported by a plurality of elastic supports 102 and are provided with two pairs of vibrators 101 having vibration modes that vibrate in opposite phases. Details of the inertial sensor elements 2 and 3 will be described later with reference to FIGS.

The inertial sensor 1 detects angular velocities around three axes. Specifically, two inertial sensor elements (biaxial angular velocity sensors) 2 and 3 that detect angular velocities around two axes are used. A detection axis corresponding to the same detection axis as that of the inertial sensor element 2 in the inertial sensor element 3 is arranged on the substrate 10 at an angle of 90 degrees with respect to a detection axis of the inertial sensor element 2. As shown, the inertial sensor element 2 and the inertial sensor element 3 are arranged.

  That is, if the driving vibration direction of one biaxial inertial sensor element (for example, inertial sensor element 2) is the X-axis direction, the driving vibration direction of the other biaxial inertial sensor element (for example, inertial sensor element 3) is referred to as the Y-axis direction. It will be.

  As a result, one of the two-axis inertial sensor elements (for example, inertial sensor element 2) can detect angular velocities around the Y-axis and Z-axis with respect to drive vibration in the X-axis direction, and can detect angular velocities around the X-axis. Although the other two-axis inertial sensor element (for example, inertial sensor element 3) is driven in the Y-axis direction, angular velocity around the X-axis and Z-axis can be detected. Can be detected.

  In the inertial sensor 1, the two inertial sensor elements 2 and 3 are used. However, it is possible to provide three or more inertial sensor elements on the first substrate 100. By providing a large number of inertial sensor elements, the detection sensitivity can be improved by adding the detection outputs of the inertial sensor elements arranged in the same direction.

  Next, the configuration of the inertial sensor element capable of detecting the angular velocity in the biaxial direction will be described in detail.

  As shown in FIGS. 2 to 6, the inertial sensor elements (angular velocity detection devices) 2 and 3 include a first vibrator 101-1 and a second vibrator 101-2 in parallel. For example, the first vibrator 101-1 is a drive-side vibrator, and the second vibrator 101-2 is an excitation-side vibrator. The first vibrator 101-1 and the second vibrator 101-2 are both made of a rectangular thin film, and are formed of silicon as an example.

  The first vibrator 101-1 and the second vibrator 101-2 are connected to each other at the corners facing each other by elastic support bodies 102-5 and 102-6. 103-6. Further, the first vibrator 101-1 is supported at one end side of the elastic supports 102-1 and 102-2 at the corner opposite to the second vibrator 101-2. The other ends of the elastic supports 102-1 and 102-2 are supported and fixed to the support portions 103-1 and 103-2, respectively. Further, the second vibrator 101-2 is supported at one end side of the elastic supports 102-3 and 102-4 at a corner portion on the opposite side to the first vibrator 101-1. The other ends of the elastic supports 102-3 and 102-4 are supported and fixed to the support portions 103-3 and 103-4, respectively. Each of the elastic supports 102-1 to 10-6 is configured by, for example, a leaf spring and is made of, for example, silicon, and various shapes can be adopted as appropriate, for example, the illustrated shape. The support portions 103-1, 103-2, 103-3, and 103-4 are formed on the first substrate 100 via the insulating film 104. The first substrate 100 is made of, for example, a silicon substrate. Therefore, the first vibrator 101-1 and the second vibrator 101-2 are supported only by the elastic supports 102-1, 102-2, 102-3, 102-4, 102-5, and 102-6. The first substrate 100 is completely floated. The first substrate 100 is made of, for example, a silicon substrate. Further, the support portions 103-1 to 103-1 formed on the first substrate 100 are formed via an insulating film 104. Note that the insulating film 104 is not necessarily formed when the first substrate 100 is a glass substrate.

  A magnetic body 300 is formed on the back side of the first substrate 100. The magnetic body 300 is made of, for example, a permanent magnet. The magnetic body 300 can be installed on the second substrate 200 described later.

  The support unit 103-1, the elastic support member 102-1, the first vibrator 101-1, and the elastic support member 102-2 are passed through to the support unit 103-2. An electrode 108-1 for detection is disposed via an insulating film 107. Similarly, the second vibrator 101-2 extends from the support section 103-3 to the support section 103-4 through the elastic support body 102-3, the second vibrator 101-2, and the elastic support body 102-4. The electrode 108-2 for electromagnetically driving is disposed via the insulating film 107.

  Further, in the Y direction of the first vibrator 101-1 and the second vibrator 101-2, an electrostatic detection electrode 109-1 that detects the displacement of the two pairs of vibrators in the Y direction as a change in capacitance. 2, 109-3, 4 are formed at intervals on each side of the first vibrator 101-1 and the second vibrator 101-2. Each of the electrostatic detection electrodes 109-1 to 109-4 is connected to extraction electrodes 122-1, 122-3, 122-4, and 122-6, which will be described later, via contact parts 123-1 to 123-4. Here, as shown in (1) the plane layout diagram of FIG. 7 and the schematic cross-sectional view showing the configuration position of the detection electrode, if the angular velocity around the Y axis is applied to the drive vibration Fxd in the X axis direction, the Z axis A direction Coriolis force Fzc is generated. Therefore, if the Coriolis force Fzc in the Z-axis direction is detected, the angular velocity around the Y-axis can be determined. Further, when an angular velocity around the Z axis is applied to the drive vibration Fxd in the X axis direction, a Coriolis force Fyc in the Y axis direction is generated. Therefore, if the Coriolis force Fyc in the Y-axis direction is detected, the angular velocity around the Z-axis can be determined. Note that the vibration modes of the first and second vibrators 101-1 and 101-2 are opposite in phase.

  2 to 6, a second substrate 200 is formed on the first substrate 100 via a frame 121. The second substrate 200 is made of, for example, a glass substrate. The second substrate 200 and the frame 121 are bonded by, for example, anodic bonding. The second substrate 200 can be a silicon substrate. In this case, it is preferable to form an insulating film between the second substrate 200 and conductive parts such as electrodes formed on the second substrate 200. When the second substrate 200 is formed of a silicon substrate, the bonding to the frame 121 can be performed by an Au—Au bonding method, an Au—Sn bonding method, a room temperature bonding method, or the like.

  On the surface of the second substrate 200 facing the first substrate 100, there is a Z-axis electrostatic detection electrode 120-1 at a position facing the electrode 108-1 formed on the first vibrator 101-1. An XY-axis electrostatic detection electrode 120-2 and a Z-axis electrostatic detection electrode 120-3 are formed, and the Z-axis electrostatic detection electrode 120-3 is positioned opposite to the electrode 108-2 formed on the second vibrator 101-2. An electrostatic detection electrode 120-4, an XY-axis electrostatic detection electrode 120-5, and a Z-axis electrostatic detection electrode 120-6 are formed. Lead electrodes 122-1 to 122-6 are connected to the detection electrodes 120-1 to 120-6, respectively.

  The second substrate 200 is connected to the electrodes 108-1 on the support portions 103-1, 103-2, and lead electrodes 124-1, 124- for pulling out the electrodes 108-1 to the outside. 2 is formed through the contact parts 125-1 and 125-2, and is connected to the electrode 108-2 on the support parts 103-3 and 103-4, and is used to draw the electrode 108-2 to the outside. Electrodes 124-3 and 124-4 are formed through contact portions 125-3 and 125-4.

  Further, electrodes 126-1 to 12-4 are formed on the second substrate 200 at positions facing the elastic supports 102-1 to 102-4, and lead electrodes 127-1 to 4 are formed on the respective electrodes 126-1 to 126-4. Has been.

  On the first substrate 100, equipotential wirings 128-1 and 128-2 are formed on the outer side of the frame 121 via the insulating film 104 at positions facing the frame 121 and facing the frame 121. Has been. The frame 121 and the equipotential wirings 128-1 and 128-2 are made of, for example, silicon.

  Next, the operation and detection principle of the inertial sensor elements 2 and 3 will be described below.

  First, the operation and detection principle of the inertial sensor element (angular velocity sensor) 2 that detects the angular velocity around the two axes will be described.

The inertial sensor elements 2 and 3 are electromagnetically driven by a magnetic body 300 made of a permanent magnet disposed under the first substrate 100. A current having a certain period is passed through the electrode 108-1 for electromagnetic driving. Since the current has a periodicity, the flow direction may be reversed at another time. When a current flows through the electrode 108-1, a Lorentz force is generated in the X-axis direction by a magnetic field from the magnetic body 300 installed below (or above) the first vibrator 101-1 for driving. The Lorentz force F _lorentz is _expressed by the following equation, and the force is induced in a direction orthogonal to the wiring.

F _lorentz = IBL

  Here, I is the current flowing through the electrode, B is the magnetic flux density, and L is the length of the electrode wiring.

  The Lorentz force is applied to the first vibrator 101-1 with the same periodicity as the applied current, and the elastic vibrators 102-1, 2, 5 and 6 are connected to the first vibrator 101-1 on the driving side. The supporting parts 103-1, 2, 5, 6 are fixed points, and the movement is repeated periodically.

  The other second vibrator 101-2 repeats the movement while having a certain phase shift with the support portions 103-3 to 10-3 to which the elastic supports 103-3 to 6-6 are connected as a fixed point.

At this time, when an angular velocity is applied from the outside around the Y axis, a Coriolis force is generated in a direction (Z axis direction) perpendicular to the vibration direction. The Coriolis force F _coriolis is _expressed by the following equation.

F _coriolis = 2mVΩ

  Here, m is the mass of the vibrator, v is the vibration velocity in the driving direction, and Ω is the angular velocity applied from the outside.

In order to increase the displacement generated by the Coriolis force, it is necessary to increase the mass m, the drive angular frequency ωy, and the drive displacement _{ym (} ωy _{and ym are parameters corresponding to the drive vibration velocity v)} . In the case of electromagnetic driving, since a comb electrode necessary for electrostatic driving is not required, a large displacement can be taken.

  When the Coriolis force is generated, the first and second vibrators 101-1 and 101-2 are vibrated in the Z-axis direction. At that time, since the flat detection electrodes 120-1 to 120-6 are arranged on the upper portions of the first and second vibrators 101-1 and 101-2, the capacitance changes between the electrodes.

  Here, by controlling the frequency of voltage application, one vibrator (for example, the first vibrator 101-1) moves in a direction approaching the electrode formed on the second substrate 200, and the other vibrator (for example, the second vibrator). The vibrator 101-2) moves away. Naturally, it moves in reverse.

  Here, a difference between the capacitance between the first vibrator 101-1 and the detection electrodes 120-1 to 120-3 and the capacitance between the second vibrator 101-2 and the detection electrodes 120-4 to 6, that is, a capacitance difference is detected. Thus, the applied angular velocity is calculated. When angular velocity is applied, the amount of capacitance change generated between each electrode and the vibrator differs. However, when translational acceleration is applied, the amount of capacitance change that occurs does not differ. There is no difference. Therefore, it has a structure capable of removing the acceleration component generated when the angular velocity is applied.

  Further, when reading the capacitance change, a carrier wave is placed between the electrode on the second substrate 200 side and the vibrator, and an actual signal is extracted by amplifying the current generated by the capacitance change. The carrier wave is removed by synchronous detection, and a DC signal corresponding to the angular velocity can be extracted by detecting the driving wave with the periodic component of the induced electromotive force. Therefore, the displacement in the Z direction of the vibrator due to the Coriolis force generated in the Z-axis direction is detected as a change in capacitance by the flat electrostatic electrode 120 formed on the second substrate 200 surface. Thereby, the angular velocity around the Y axis can be detected.

  Similarly, when driving vibration is performed in the X-axis direction, if an angular velocity is applied from the outside around the Z-axis, a Coriolis force is generated in a direction perpendicular to the vibration direction (Y-axis direction). When the Coriolis force is generated, the first and second vibrators 101-1 and 101-2 are vibrated in the Y-axis direction. At this time, since the electrostatic detection electrodes 109-1 to 4-4 having flat plates are arranged on the sides of the first and second vibrators 101-1 and 101-2, respectively, the capacitance between the vibrator and the electrodes. Change occurs.

  By controlling the voltage application frequency described above, one vibrator (for example, the first vibrator 101-1) moves in a direction approaching the electrode formed on the second substrate 200, and the other vibrator (for example, the first vibrator 101-1). The second vibrator 101-2) moves away. Naturally, it moves in reverse.

  Here, the difference between the capacitance between the first vibrator 101-1 and the detection electrodes 109-1, 2 and the capacitance between the second vibrator 101-2 and the electrostatic detection electrodes 109-3, 4, ie, the capacitance difference. Is detected to calculate the applied angular velocity. When the angular velocity is applied, the capacitance change amount generated between each of the detection electrodes 109-1 to 10-4 and the first and second vibrators 101-1 and 2 is different, but is generated when the translational acceleration is applied. Since the amount of capacitance change to be made is not different, there is no difference in capacitance even if the difference is taken. Therefore, it has a structure capable of removing the acceleration component generated when the angular velocity is applied.

  Further, when reading the capacitance change, a carrier wave is placed between the electrode on the second substrate 200 side and the vibrator, and an actual signal is extracted by amplifying the current generated by the capacitance change. The carrier wave is removed by synchronous detection, and a DC signal corresponding to the angular velocity can be extracted by detecting the driving wave with the periodic component of the induced electromotive force. Therefore, the displacement in the Y direction of the vibrator due to the Coriolis force generated in the Y-axis direction is electrostatically caused by the flat electrostatic electrodes 109-1 to 10-4 formed on the sides of the first and second vibrators 101-1 and 101-2. It is detected as a change in capacity. Thereby, the angular velocity around the Y axis can be detected.

  Moreover, by using the electrostatic detection electrodes 120-1 to 6 and 109-1 to 4 for detecting Coriolis force when the angular velocity is applied as flat plate electrostatic detection electrodes, than a sensor having a conventional comb electrode, Since the drive vibration amplitude can be increased without being restricted by the gap (gap) between the electrostatic detection electrode and the vibrator, the detection sensitivity of the angular velocity is improved.

  The inertial sensor 1 is an electrostatic detection method, and is supported by a plurality of elastic supports 102-1 to 102-6, and has two pairs of vibrators (firsts) that have vibration modes that drive and vibrate in opposite phases to each other. Since the first vibrator 101-1 and the second vibrator 101-2) are provided, the driving vibration of the two pairs of vibrators is set to a vibration mode that vibrates in opposite phases, and the vibrator displacement caused by the Coriolis force is electrostatically Detection is performed based on a difference in capacitance between the electrostatic detection electrodes 120-1 to 6 and 109-1 to 4 and the two pairs of vibrators that form the detection method. From this, when the angular velocity is applied, the capacitance change amount generated between each electrode and the vibrator is different, and when the translational acceleration is applied, the generated capacitance change amount is not different. However, there is no difference in capacity. Therefore, even if external acceleration is applied during application of the angular velocity, the translational acceleration can be removed, so that the sensitivity of detecting the angular velocity is improved. In addition, by adopting the electromagnetic driving method, the driving method of the vibrator can be increased as compared with the electrostatic driving method using the comb-shaped electrode, so that the detection sensitivity of the angular velocity is further improved.

  Therefore, a biaxial angular velocity sensor or a triaxial angular velocity sensor can be provided without being affected by external acceleration, and since the electromagnetic drive method is used, the drive vibration amplitude can be increased, so that the detection sensitivity of angular velocity can be improved. There is an advantage.

  Further, since the electrostatic detection electrode for detecting the Coriolis force when the angular velocity is applied is a flat electrostatic detection electrode, the electrostatic detection electrodes 120-1 to 120-6 and the vibrator ( Since the drive vibration amplitude can be increased without being restricted by the gap between the first vibrator 101-1 and the second vibrator 101-2), the angular velocity detection sensitivity is improved. Further, by making the resonance frequency for detecting the driving vibration frequency and the Coriolis force close to each other by controlling the rigidity of the plurality of elastic supports, the detection sensitivity of the angular velocity is improved as compared with the sensor having the comb-shaped electrode. As described above, since the detection sensitivity of the angular velocity is improved, the inertial sensor 1 is more effective when used for an angular velocity sensor, for example.

  Next, a method for manufacturing the inertial sensor 1 will be described. The inertial sensor 1 has at least one set of inertial sensor elements, for example, inertial sensor elements 2 and 3 on the same substrate, for example, the first substrate 100, arranged in directions orthogonal to each other on the first substrate 100. And so on. At that time, the same components of the inertial sensor elements 2 and 3 are simultaneously manufactured in the same process.

  Specifically, for example, an SOI substrate is prepared.

  Hereinafter, a manufacturing method for one inertial sensor element (for example, inertial sensor element 2) will be described. Similarly to inertial sensor element 2, the other inertial sensor element (for example, inertial sensor element 3) is formed at the same time.

  The silicon layer of the SOI substrate is processed to form the vibrator formation region, the frame 121, and the same potential wirings 128-1,2. Next, electrodes 108-1 and 108-2 are formed on the silicon layer with an insulating film 107 interposed therebetween. Next, the silicon layer in the vibrator formation region is processed to form the first vibrator 101-1, the second vibrator 101-2, the elastic support portions 102-1 to 102-6, the support portions 103-1 to 6-1, and the like. To do.

  Next, a second substrate 200 (for example, a glass substrate) is prepared, and electrostatic detection electrodes 120-1 to 6, 109-1, 2 and the like are formed. Then, after forming contact portions 123-1 to 12 and 125-1 to 4 to connect the electrodes, the frame 121 formed on the first substrate 100 and the second substrate 200 are joined. At that time, each electrode on the first substrate 100 side and each electrode on the second substrate 200 side are connected by a contact portion. Furthermore, for example, a permanent magnet is disposed on the back surface of the first substrate 100 as the magnetic body 300.

  In this way, inertial sensor elements 2 and 3 are formed.

  According to the inertial sensor manufacturing method of the present invention, the detection axes of the inertial sensor elements 2 and 3 can be eliminated because the detection axes of the inertial sensor elements 2 and 3 can be perfectly aligned. There is an advantage that a sensitive angular velocity can be detected.

  Further, according to the present invention, each inertial sensor element can be manufactured on the same substrate by the same process. For example, the configuration described in Japanese Patent Application Laid-Open No. 2005-283428 (hereinafter referred to as Prior Art 1), that is, Three angular velocity sensor chips and three axes that are detected by the three angular velocity sensor chips intersect at one point, and three axes that are detected by the three acceleration sensor chips intersect at one point. Compared to a configuration in which acceleration sensor chips are mounted on the same mounted member, and a configuration in which three angular velocity sensor chips and three acceleration sensor chips are stacked and mounted, the size and thickness can be reduced. Become.

  Further, for example, a configuration described in Japanese Patent Application Laid-Open No. 2001-183162 (hereinafter referred to as Conventional Technology 2), that is, three angular velocity sensor chips, one acceleration sensor chip for detecting biaxial acceleration, and two axes One geomagnetic sensor chip for detecting geomagnetism is mounted on two boards, and the boards are electrically connected via inter-board connectors, making it smaller and thinner than the configuration housed in the housing Can be realized.

  Furthermore, since the conventional techniques 1 and 2 have three uniaxial angular velocity sensor chips mounted to detect angular velocities around three axes, it is difficult to perfectly align the detection axes at the time of mounting. In the present invention, since each inertial sensor element can be manufactured on the same substrate by the same process, the same components of each inertial sensor element can be formed in the same mask. Therefore, the detection axes of the inertial sensor elements can be perfectly aligned.

FIG. 2 is a plan layout view of (1) showing an inertial sensor of an embodiment (first example) of the inertial sensor of the present invention, and a schematic cross-sectional view showing a configuration position of detection electrodes of (2). It is the plane layout figure which showed the inertial sensor element. It is the plane layout figure which showed the electrode of the inertial sensor element. FIG. 3 is a cross-sectional view taken along line A-A ′ in FIG. 2. FIG. 3 is a sectional view taken along line B-B ′ in FIG. 2. FIG. 3 is a sectional view taken along line C-C ′ in FIG. 2. It is a figure explaining the angular velocity detection around the Y-axis and Z-axis in a biaxial inertial sensor element.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Inertial sensor, 2, 3 ... Inertial sensor element, 10 ... Board | substrate, 101-1 ... 1st vibrator | oscillator, 101-2 ... 2nd vibrator | oscillator, 102-1-6 ... Elastic support body

Claims (4)

Using electromagnetic drive method and electrostatic detection method,
A plurality of inertial sensor elements that detect angular velocity in two axial directions by driving vibration in one axial direction among three axes orthogonal to each other are formed on the same substrate.
At least one set of inertial sensor elements of the inertial sensor elements are arranged in directions orthogonal to each other on the substrate,
The plurality of inertial sensor elements are supported by a plurality of elastic supports, and include two pairs of vibrators having vibration modes that vibrate in opposite phases to each other. 2. The inertia according to claim 1, wherein displacement due to the Coriolis force of each of the vibrators is detected by a capacitance change difference between the vibrator and an electrostatic detection electrode provided at a position facing the vibrator. Sensor. The inertial sensor according to claim 1, wherein the electrostatic detection electrode has a flat plate shape. Using electromagnetic drive method and electrostatic detection method,
A method for manufacturing an inertial sensor, wherein a plurality of inertial sensor elements that detect angular velocity in two axial directions by driving vibration in one axial direction among three axes orthogonal to each other are formed on the same substrate,
At least one set of inertial sensor elements of the inertial sensor elements is disposed in a direction orthogonal to each other on the substrate;
Each inertial sensor element is formed on the same substrate in the same process. A method for manufacturing an inertial sensor.

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