Mounting structure of micro vibrator

Abstract

To provide a mounting structure with a micro vibrator having a three-dimensional curved shape and a surface electrode covering the same bonded to a mounting board capable of reducing noise caused by a plane of the electrode other than the plane facing the micro vibrator.SOLUTION: A mounting board 3 mounted with a micro vibrator 2 that has a curved surface portion 21 having an annular curved surface and a connection part 22 extending from the curved surface portion to the center inside the curved surface portion includes multiple first electrode parts 53 that have a guard electrode 534 and enclose the micro vibrator 2. Each of the multiple first electrode parts 53 has an opposite surface 531a facing a rim 211, which is the edge of the curved surface portion 21 at the opposite side from the connection part 22. A surface of multiple first electrode parts 53 that is different from the opposite surface 531a and includes at least an upper surface 531b on the opposite side from the mounting board 3 has an insulating film 533 and a guard electrode 534 that is formed on the insulating film 533 electrically independent from the first electrode part 53.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a mounting structure for a micro-vibrator having a three-dimensional curved surface shape. [Background technology]

[0002] In recent years, the development of autonomous driving systems for vehicles has progressed, and these types of systems require highly accurate self-position estimation technology. For example, for so-called Level 3 autonomous driving, development is underway on a self-position estimation system equipped with a GNSS (Global Navigation Satellite System) and an IMU (Inertial Measurement Unit). The IMU is a six-axis inertial force sensor consisting of, for example, a three-axis gyro sensor and a three-axis acceleration sensor. In order to realize so-called Level 4 or higher autonomous driving in the future, an IMU with even higher sensitivity than currently available will be required.

[0003] The BRG (Bird-bath Resonator Gyroscope) is considered to be a promising gyro sensor for realizing such a highly sensitive IMU. It is made up of a micro-vibrator with a roughly hemispherical three-dimensional curved surface that vibrates in wine-glass mode and is mounted on a mounting board. This micro-vibrator has a Q value that indicates the state of vibration of 10. 6 This is expected to result in higher sensitivity than conventional methods.

[0004] An example of this type of mounting structure between a micro-vibrator and a mounting substrate is described in Patent Document 1. In this mounting structure, a columnar joint extending from near the apex of the three-dimensionally curved, approximately hemispherical surface of the micro-vibrator toward the center of the inside of the hemisphere is inserted into a bonding region of the mounting substrate surrounded by a substantially annular frame. In this mounting structure, a surface electrode covering the entire surface of the micro-vibrator is bonded to wiring formed in the bonding region of the mounting substrate, and a predetermined voltage can be applied to the surface electrode of the micro-vibrator via the wiring of the mounting substrate. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Chinese Patent Application Publication No. 107036705 Summary of the Invention [Problem to be solved by the invention]

[0006] This BRG applies a voltage to the surface electrode of the micro-vibrator bonded to the bonding area electrically connected to the wiring formed on the mounting substrate, vibrating the micro-vibrator, while detecting the capacitance between the opposing surface electrode of the micro-vibrator and the electrode portion of the mounting substrate. However, according to careful investigation by the inventors, it has been found that the electrode portion of the mounting substrate also electrically affects the side surface of the micro-vibrator from surfaces other than the surface facing the micro-vibrator, and there is a concern that this may be superimposed as noise on the detected capacitance.

[0007] In view of the above, an object of the present invention is to reduce noise caused by surfaces of the electrode portion other than the surface facing the micro-vibrator in a mounting structure in which a micro-vibrator having a three-dimensional curved surface shape and a surface electrode covering the micro-vibrator is bonded to a mounting substrate. [Means for solving the problem]

[0008] In order to achieve the above object, the mounting structure of a micro-vibrator described in claim 1 is a mounting structure for a micro-vibrator (2), and includes: a micro-vibrator having a curved surface portion (21) having a ring-shaped curved surface and a connecting portion (22) extending from the curved surface portion to the center inside the curved surface portion; and a mounting substrate (3) having a rim (211) at an end of the curved surface portion opposite the connecting portion, facing the rim and surrounding the rim, and having a plurality of electrode portions (53) arranged at a distance from each other, wherein the connecting portion of the micro-vibrator is joined to the mounting substrate and the curved surface portion is in a hollow state not in contact with other members, and the plurality of electrode portions have a base (531) having an opposing surface (531a) facing the rim, an insulating film (533) that is a surface of the base different from the opposing surface and covers at least a portion including an upper surface (531b) opposite the mounting substrate, and a guard electrode (534) formed on the insulating film, covering at least the upper surface, and electrically independent from the base.

[0009] This mounting structure includes a micro-vibrator having a three-dimensional curved surface and a plurality of electrode portions disposed on a mounting substrate, the electrode portions being spaced apart from one another and surrounding the rim of the micro-vibrator. A guard electrode electrically independent of the electrode portions covers a portion of the electrode portions. The guard electrode covers at least the top surfaces of the electrode portions, which are opposite the mounting substrate and are different from the surfaces facing the rim of the micro-vibrator. This configuration blocks electric field lines from the top surfaces of the electrode portions toward the micro-vibrator when a voltage is applied to the electrode portions, thereby reducing electrical influence on the micro-vibrator due to the top surface. This mounting structure therefore reduces noise due to surfaces of the electrode portions other than the surface facing the micro-vibrator.

[0010] The mounting structure of a micro-vibrator according to claim 5 is a mounting structure for a micro-vibrator (2), and includes: a micro-vibrator having a curved surface portion (21) having an annular curved surface; and a connecting portion (22) extending from the curved surface portion to the center of the inside of the curved surface portion; and a mounting substrate (3) having a rim (211) at an end of the curved surface portion opposite the connecting portion, and a plurality of electrode portions (53) and a plurality of guard electrodes (55) that face the rim, surround the rim, and are arranged at a distance from each other; the connecting portion of the micro-vibrator is joined to the mounting substrate, and the curved surface portion is in a hollow state not in contact with other members, and at least one of the plurality of guard electrodes is arranged between adjacent electrode portions. The plurality of electrode portions are provided with a base portion (531) having an opposing portion (5311) that faces the rim, a terminal portion (5313) that is disposed on the opposite side of the rim across the opposing portion, and a narrow portion (5312) that connects the opposing portion and the terminal portion and is narrower than the opposing portion and the terminal portion, and the opposing portion has a width at the end on the rim side that is larger than the end on the narrow portion side and has the smallest width at the end on the narrow portion side. .

[0011] This mounting structure includes a micro-vibrator having a three-dimensional curved surface, and a plurality of electrode portions and a plurality of guard electrodes disposed on a mounting substrate, surrounding the rim of the micro-vibrator and spaced apart from one another, with at least one guard electrode disposed between adjacent electrode portions. By disposing at least one guard electrode between adjacent electrode portions, the area of ​​the top surface of the plurality of electrode portions, which is a surface opposite the mounting substrate and different from the surface facing the rim of the micro-vibrator, is relatively smaller than in a case where the guard electrode is not disposed. As a result, when a voltage is applied to the plurality of electrode portions, the electric field lines from the top surface toward the micro-vibrator are reduced by the amount of the reduced area of ​​the top surface, thereby reducing electrical influences. This mounting structure thus reduces noise caused by surfaces of the plurality of electrode portions other than the surface facing the micro-vibrator.

[0012] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and the specific components described in the embodiments described below. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a perspective view showing an inertial sensor according to a first embodiment. [Figure 2] FIG. 2 is a perspective cross-sectional view including a cross section of the inertial sensor of FIG. 1. [Figure 3] FIG. 3 is a cross-sectional view taken along the line III-III in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. [Figure 5A] 10A and 10B are explanatory diagrams for explaining noise generation due to the upper surface of the electrode portion in the mounting structure of the comparative example. [Figure 5B] 10A and 10B are explanatory diagrams for explaining changes in electric lines of force accompanying excitation of a micro-vibrator in a mounting structure of a comparative example. [Figure 6A] 10A and 10B are cross-sectional views showing a member preparation step in the microvibrator formation step. [Figure 6B] FIG. 6B is a cross-sectional view showing the step of forming the microvibrator subsequent to FIG. 6A. [Figure 6C] FIG. 6C is a cross-sectional view showing the microvibrator forming step subsequent to FIG. 6B. [Figure 7A] 3 is a cross-sectional view showing a step of forming a mounting substrate in the manufacturing process of the inertial sensor of the first embodiment. FIG. [Figure 7B] FIG. 7B is a cross-sectional view showing a step subsequent to FIG. 7A. [Figure 7C] FIG. 7C is a cross-sectional view showing a step subsequent to FIG. 7B. [Figure 7D] FIG. 7D is a cross-sectional view showing a step subsequent to FIG. 7C. [Figure 8A] FIG. 7B is a cross-sectional view showing a step subsequent to FIG. 7D. [Figure 8B] FIG. 8B is a cross-sectional view showing a step subsequent to FIG. 8A. [Figure 8C] FIG. 8C is a cross-sectional view showing a step subsequent to FIG. 8B. [Figure 8D] FIG. 8D is a cross-sectional view showing a step subsequent to FIG. 8C. [Figure 8E] FIG. 8E is a cross-sectional view showing a step subsequent to FIG. 8D. [Figure 8F] FIG. 8C is a cross-sectional view showing a step subsequent to FIG. 8E. [Figure 9A] FIG. 7B is a cross-sectional view showing a step subsequent to FIG. 7D. [Figure 9B] FIG. 9B is a cross-sectional view showing a step subsequent to FIG. 9A. [Figure 9C] FIG. 9C is a cross-sectional view showing a step subsequent to FIG. 9B. [Figure 9D] FIG. 9D is a cross-sectional view showing a step subsequent to FIG. 9C. [Figure 9E] FIG. 9B is a cross-sectional view showing a step subsequent to FIG. 9D. [Figure 9F] FIG. 9B is a cross-sectional view showing a step subsequent to FIG. 9E. [Figure 10] FIG. 10 is a top view layout diagram showing the inertial sensor of the second embodiment. [Figure 11] 11 is a cross-sectional view taken along the line XI-XI in FIG. [Figure 12] FIG. 12 is a cross-sectional view corresponding to FIG. 11, showing a modified example of the inertial sensor of the second embodiment. [Figure 13] FIG. 10 is a top view layout diagram illustrating an example of an inertial sensor according to another embodiment. [Figure 14] FIG. 10 is a top view layout diagram illustrating an example of an inertial sensor according to another embodiment. [Figure 15] FIG. 4 is a cross-sectional view corresponding to FIG. 3 and showing an example of an inertial sensor according to another embodiment. [Figure 16] 3 is a perspective cross-sectional view corresponding to FIG. 2, showing an example of an inertial sensor according to another embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following embodiments, identical or equivalent parts will be denoted by the same reference numerals.

[0015] (First embodiment) A mounting structure 1 of a first embodiment will be described with reference to the drawings. The mounting structure 1 of this embodiment has a micro-vibrator 2 that vibrates in a wine-glass mode, and is suitable for application to various devices that utilize the vibration characteristics of the micro-vibrator 2, for example, inertial sensors such as gyro sensors, such as BRGs. In this specification, a case in which the mounting structure 1 is applied to a BRG will be described as a representative example, but the application is not limited to this.

[0016] In FIG. 1, in order to make it easier to understand the configuration of the micro-vibrator 2 and the mounting substrate 3, which will be described later, the parts of the outer periphery of the micro-vibrator 2 and the mounting substrate 3 that cannot be seen from the angles shown in FIGS. 1 and 2 are shown by dashed lines or two-dot chain lines.

[0017] For ease of explanation, as shown in FIG. 1, a direction in the planar direction of the mounting substrate 3, which is a direction along one side of the outer periphery, will be referred to as the "x-direction," a direction perpendicular to the x-direction in the same planar direction will be referred to as the "y-direction," and a direction normal to the xy plane will be referred to as the "z-direction." The x, y, and z directions in FIG. 2 and subsequent figures correspond to the x, y, and z directions in FIG. 1, respectively. In addition, in this specification, "up" refers to the direction along the z-direction in the figure, and refers to the side indicated by the arrow, and "down" refers to the side opposite to the top. Furthermore, in this specification, the state in which the mounting structure 1 or the mounting substrate 3 is viewed from above in the z-direction will sometimes be referred to as a "top view."

[0018] 1, the mounting structure 1 of this embodiment includes a micro-vibrator 2 and a mounting substrate 3, with a portion of the micro-vibrator 2 bonded to the mounting substrate 3. The mounting structure 1 is configured to detect an angular velocity applied to the mounting structure 1 based on a change in capacitance between the thin-walled micro-vibrator 2 capable of vibrating in a wine-glass mode and a plurality of electrode portions 53 (described later) on the mounting substrate 3.

[0019] As shown in Figures 2 to 4, the micro-vibrator 2 has a curved surface portion 21 including the contour of a three-dimensional curved surface in a hemispherical shape, and a connecting portion 22 extending from the vertex side of the imaginary hemisphere formed by the curved surface portion 21 toward the center of the inside of the hemisphere. The connecting portion 22 is, for example, a cylindrical recess with a bottom. The micro-vibrator 2 has, for example, a curved surface portion 21 that has a bowl-shaped three-dimensional curved surface, and the Q value of the vibration is 10 5 That's all.

[0020] The end of the curved surface portion 21 opposite the connection portion 22 is the rim 211, and the rim 211 has, for example, a substantially cylindrical shape. When the micro-vibrator 2 is mounted on the mounting substrate 3, for example, the surface 2a of the rim 211 faces a plurality of electrode portions 53 (described later) of the mounting substrate 3, and the plurality of electrode portions 53 are mounted so that they are equally spaced apart. When mounted on the mounting substrate 3, the curved surface portion 21 including the rim 211 is in a hollow state, not in contact with other components. When mounted on the mounting substrate 3, the micro-vibrator 2 has a structure that allows the hollow rim 211 to vibrate in a wine glass mode by applying a voltage to the plurality of electrode portions 53.

[0021] 3 and 4, the micro-vibrator 2 has a surface with a larger outer diameter as the front surface 2a and a back surface 2b on the opposite side, with a front surface electrode 23 covering part or all of both surfaces. The surface of the connecting portion 22 of the micro-vibrator 2 facing the back surface 2b serves as a mounting surface 22b that faces the mounting substrate 3. In this embodiment, the surface of the bottom of the connecting portion 22 opposite the mounting surface 22b serves as an adsorption surface 22a that is used to adsorb and transport the micro-vibrator 2.

[0022] The surface electrode 23 may be, for example, but not limited to, a laminated film of a conductive material, such as Cr (chromium) or Ti (titanium), and an appropriate conductive material, such as Au (gold) or Pt (platinum), from the base side, or a single-layer film of a conductive material, such as TiN (titanium nitride), that adheres well to the substrate. The surface electrode 23 is formed on the front surface 2a and rear surface 2b of the micro-vibrator 2 by any film-forming method, such as sputtering, vapor deposition, or ALD (atomic layer deposition). In this embodiment, the surface electrode 23 is formed on at least the mounting surface 22b and the front surface 2a or rear surface 2b of the rim 211, and these portions are electrically connected. The surface electrode 23 may be a solid shape that covers the entire front and rear surfaces of the micro-vibrator 2, or may be patterned to have the above-described configuration and cover a portion of the front and rear surfaces. The portion of the surface electrode 23 that covers the mounting surface 22b of the connection portion 22 of the micro-vibrator 2 is connected to a bridge wiring 42 (described later) of the mounting substrate 3 via a bonding member 52.

[0023] The micro-vibrator 2 is made of materials such as quartz, glass containing additives such as borosilicate glass, metallic glass, silicon, and ceramic. The micro-vibrator 2 is not limited to the materials mentioned above, as long as it can form the curved surface portion 21 and the connecting portion 22, which are three-dimensionally curved, and can vibrate in wine-glass mode. The micro-vibrator 2 is formed, for example, by processing a thin-walled base material made of the above-mentioned materials through a forming process described below, resulting in a thin member on the order of micrometers, with the curved surface portion 21 and the connecting portion 22 having thicknesses of 10 μm to 100 μm. The micro-vibrator 2 has a millimeter-sized shape, with the height dimension being 2.5 mm, and the outer diameter of the rim 211 on the surface 2a side being 5 mm, with the height direction being the thickness direction of the mounting substrate 3. The forming process of the micro-vibrator 2 will be described later.

[0024] 1, the mounting substrate 3 includes a lower substrate 4 and an upper substrate 5, which are bonded together. For example, the mounting substrate 3 can be obtained by anodic bonding the upper substrate 5, which is made of silicon (Si), a semiconductor material, to the lower substrate 4, which is made of borosilicate glass, an insulating material. The mounting substrate 3 includes, for example, an inner frame 51 on the side of the upper substrate 5, a plurality of first electrode portions 53 arranged at a distance from each other and surrounding the inner frame 51, and second electrode portions 54 arranged at a distance from each other outside the electrode portions 53. The mounting substrate 3 also includes, for example, an annular groove 41 on the side of the lower substrate 4 that surrounds the inner frame 51 and separates the inner frame 51 from the plurality of first electrode portions 53, and a plurality of bridge wirings 42 that span the inside and outside of the groove 41.

[0025] 3 and 4, the groove 41 is a groove provided between the inner frame portion 51 and the plurality of first electrode portions 53, and is formed by wet etching or the like. The groove 41 has a dimension corresponding to the outer diameter of the rim 211 of the micro-vibrator 2, for example, and is provided so that the rim 211 does not come into contact with the mounting substrate 3 when the micro-vibrator 2 is mounted on the mounting substrate 3.

[0026] For example, a plurality of bridge wirings 42 are formed and are made of a conductive material such as Al (aluminum). Each of the plurality of bridge wirings 42 is arranged to pass between the plurality of first electrode portions 53 and is electrically independent from the plurality of first electrode portions 53. As shown in FIGS. 3 and 4 , for example, the bridge wirings 42 straddle the etching grooves 41 in the lower substrate 4, and one end of the bridge wirings 42 is arranged in an inner region surrounded by the inner frame portion 51, and the other end is connected to the second electrode portion 54. One end of the bridge wirings 42 is connected to the surface electrode 23 of the micro-vibrator 2 inside the inner frame portion 51, and electrically connects the surface electrode 23 and the second electrode portion 54.

[0027] The inner frame portion 51 has, for example, a single annular shape as a whole when viewed from above, and the connection portion 22 of the micro-vibrator 2 is inserted inside the inner frame portion 51. As shown in FIGS. 3 and 4, for example, the inner frame portion 51 is sized so that at least its outer surface does not come into contact with the micro-vibrator 2. Note that the inner frame portion 51 may be configured, for example, by dividing a single annular frame into multiple pieces along its circumferential direction. Furthermore, the inner dimensions of the inner frame portion 51 may be sized and shaped to match the outer diameter and shape of the connection portion 22 of the micro-vibrator 2 on the back surface 2b side, and may function as a positioning jig when mounting the micro-vibrator 2 on the mounting substrate 3.

[0028] The bonding member 52 is a conductive material used to bond the micro-vibrator 2 and the mounting substrate 3, and electrically connects one end of the bridge wiring 42 to the surface electrode 23 of the micro-vibrator 2. The bonding member 52 is a conductive paste material made of a conductive material such as AuSn (gold tin), Ag (silver), or Au, and is applied to the area surrounded by the inner frame portion 51 using a syringe or the like.

[0029] 1, the multiple first electrode portions 53 are arranged at intervals from one another at positions on the outer periphery of the groove 41 so as to surround the inner frame portion 51 and the micro-oscillating body 2. Some of the multiple first electrode portions 53 function as drive electrodes that generate electrostatic attraction to the micro-oscillating body 2 when a voltage is applied, driving the micro-oscillating body 2 to vibrate. Some of the multiple first electrode portions 53 have portions that face the rim 211 of the micro-oscillating body 2, forming a capacitor together with the rim 211, and function as detection electrodes that detect the capacitance of the capacitor.

[0030] 2, the plurality of first electrode portions 53 have a first base portion 531 facing the rim 211 and a second base portion 532 arranged on the opposite side of the rim 211 with the first base portion 531 in between. The plurality of first electrode portions 53 further include, for example, an insulating film 533 covering the first base portion 531 and the second base portion 532, a guard electrode 534 arranged on the insulating film 533, and an extraction electrode 535 arranged on the second base portion 532.

[0031] At least a facing surface 531a of the first electrode portions 53, which faces the rim 211, of the first base portion 531 is exposed from the insulating film 533 and the guard electrode 534. As shown in FIG. 1 , the entire first electrode portion 53, except for the facing surface 531a, is covered with the insulating film 533 and the guard electrode 534. As shown in FIG. 1 , the entire first electrode portion 53 is covered with the insulating film 533 and the guard electrode 534, except for the surface of the second base portion 532 opposite to the first base portion 531. The first base portion 531 and the second base portion 532 are disposed on a conductive layer 43 formed on the lower substrate 4, for example, and are electrically connected via the conductive layer 43. As a result, as shown in FIG. 3 , by applying a voltage to an extraction electrode 535 provided on one surface 532a of the second base portion 532, a voltage can be applied to the first base portion 531 via the conductive layer 43.

[0032] The first base portion 531 and the second base portion 532 are made of the same material and are separately formed, for example, by etching the conductive silicon substrate that constitutes the upper substrate 5. When the first electrode portion 53 is configured as two separate base portions, the bonding area between the lower substrate 4 and the upper substrate 5 is smaller than when the first electrode portion 53 is configured as one large base portion, and the effect of reducing thermal stress on the lower substrate 4 is obtained.

[0033] The insulating film 533 is made of an insulating material such as TEOS (tetra ethoxy silane) and is formed by plasma CVD (chemical vapor deposition) or the like. The insulating film 533 is formed in a predetermined region that is different from the opposing surface 531a of the first base portion 531 and includes at least the upper surface 531b of the first base portion 531, and on the surface of the second base portion 532. This results in a configuration in which the guard electrode 534 is electrically independent from the first base portion 531 and the second base portion 532.

[0034] The guard electrode 534 is a conductive film on the insulating film 533 that covers at least the upper surface 531b of the first base portion 531. The guard electrode 534 is made of a conductive material, such as Au or Al, and is formed by sputtering or other methods in the same process as the extraction electrode 535. The guard electrode 534 is connected to, for example, a wire (not shown), allowing for external potential adjustment. The guard electrode 534 serves to shield the rim 211 of the micro-vibrator 2 from electrical interference from surfaces of the first base portion 531 other than the facing surface 531a, thereby reducing noise in capacitance detection and improving capacitance detection accuracy. In other words, the guard electrode 534 concentrates the electric field in the gap between the facing surface 531a of the first electrode portion 53 and the rim 211, thereby suppressing the generation of unintended electric fields from locations of the first electrode portion 53 other than the facing surface 531a. This will be described in detail later.

[0035] The extraction electrode 535 is a conductive film formed in a contact hole 533a of the insulating film 533 on one surface 532a of the second base portion 532, and is used to apply a voltage to the first base portion 531 and detect capacitance via the second base portion 532. The extraction electrode 535 is electrically independent from the guard electrode 534, and is connected to a wire or the like (not shown) to enable electrical communication with the outside.

[0036] As shown in FIG. 1 , for example, the second electrode portions 54 are disposed on the mounting substrate 3 closer to the outer periphery than the first electrode portions 53, and are used to apply a voltage to the surface electrodes 23 of the micro-vibrator 2. As shown in FIG. 3 , for example, the second electrode portions 54 include base portions 541 and electrode pads 542 that cover parts of the base portions 541. For example, the number of second electrode portions 54 is the same as the number of wirings 42, and the base portions 541 are disposed on the other ends of the wirings 42 opposite the micro-vibrator 2 and are electrically connected to the wirings 42. This allows the second electrode portions 54 to apply a voltage to the surface electrodes 23 of the micro-vibrator 2 via the electrode pads 542, the base portions 541, the wirings 42, and the bonding member 52.

[0037] The base portion 541 is a portion separated from the inner frame portion 51 and the first electrode portion 53, for example, by etching the conductive silicon that constitutes the upper substrate 5. The electrode pad 542 is made of, for example, the same conductive material as the guard electrode 534 and the extraction electrode 535, and is formed in the same process as these, for example, by sputtering. The electrode pad 542 is connected to, for example, a wire (not shown) or the like, similar to the extraction electrode 535, allowing electrical communication with the outside.

[0038] The above is the basic configuration of the mounting structure 1 of this embodiment. In the mounting structure 1, at least the upper surface 531b of the first electrode portion 53 is covered with the guard electrode 534 that is electrically independent from the first base portion 531, thereby reducing the electrical influence from the upper surface 531b to the upper side surface of the rim 211.

[0039] [Effect of guard electrode] Next, a description will be given of noise reduction by guard electrode 534. First, a description will be given of noise generation in mounting structure 100 of the comparative example that does not have guard electrode 534 shown in Fig. 5A.

[0040] 5A, the mounting structure 100 of the comparative example has a micro-vibrator 2 bonded to a mounting substrate 101, and the curved surface 21 of the micro-vibrator 2 is in a hollow state and does not come into contact with other components. The mounting substrate 101 has a plurality of first electrodes 102 that face the rim 211 of the micro-vibrator 2 at a predetermined distance, and the first electrodes 102 function as drive electrodes and capacitance detection electrodes for the micro-vibrator 2. The first electrodes 102 are connected to wires or the like (not shown) to enable electrical communication with the outside, but do not have guard electrodes on their upper surfaces.

[0041] The mounting structure 100 of the comparative example applies a DC voltage to the micro-vibrator 2 via wiring or the like (not shown) while applying an AC voltage to the first electrode 102, thereby exciting the curved portion 21 of the micro-vibrator 2 and detecting the capacitance between the rim 211 of the micro-vibrator 2 and the first electrode 102.

[0042] When an AC voltage, i.e., an AC drive signal, is applied to an electrode, etc., electromagnetic induction radiation noise is generally generated. Here, if the charge of the first electrode 102 is Q, the capacitance is C, and the voltage is V, then Q=CV. Furthermore, if the current when applying the AC drive signal to the first electrode 102 is i and the time is t, then the charge Q of the first electrode 102 is expressed by the following equation:

[0043]

number

[0044]

number

[0045]

number

[0046]

number

[0047] In addition, Figure 5B shows only a portion of the outer periphery of the excited micro-vibrator 2 on the surface 2a side of the curved portion 21, and the portion of the outer periphery closest to the first electrode 102 is shown by a solid line, and the portion farthest from the first electrode 102 is shown by a dashed line.

[0048] At this time, the distance between the opposing surface 102a of the first electrode 102 and the rim 211 is d1, and since d1 is short, the rate of change in the length of the electric field lines E1 due to the excitation of the micro-vibration body 2, i.e., the rate of difference between the electric field lines E11 and E12 relative to the total electric field lines E1, is large. On the other hand, the distance between the upper surface 102b of the first electrode 102 and the upper side surface of the rim 211 is d2, and since d2 is longer than d1, the rate of change in the length of the electric field lines E2 due to the excitation of the micro-vibration body 2 is relatively small compared to the electric field lines E1. The rate of change in the length of the electric field lines E2 is the rate of difference between the electric field lines E21 and E22 relative to the total electric field lines E2. Therefore, the capacitance C for the fringe effect f Assuming that the time change of dC f Substituting / dt=0 into equation 4, we obtain the following equation.

[0049]

number

[0050] In contrast, in the mounting structure 1 of the first embodiment, the upper surface 531b of the first base portion 531 of the first electrode portion 53 is covered by the guard electrode 534, and therefore the electric field lines E2 directed from the upper surface 531b to the upper side surface of the rim 211 are blocked. f is reduced, and the noise component C f dV n As a result, the noise component superimposed on the current i in the detection electrode of the first electrode portion 53 is reduced, and the detection accuracy of the capacitance between the opposing surface 531a and the rim 211 is improved.

[0051] [Method for manufacturing mounting structure] Next, an example of a method for manufacturing the mounting structure 1 of this embodiment will be described. First, the micro-vibrator 2 is formed, for example, by the following steps.

[0052] First, as shown in FIG. 6A, a quartz plate 20, a mold M0 for forming the three-dimensional curved surface, and a cooling body C0 for cooling the mold M0 are prepared. The mold M0 includes, for example, a recess M1 that provides a space for forming the three-dimensional curved surface in the quartz plate 20, and a support M2 that extends in the depth direction of the recess M1 at the center of the recess M1 and supports a portion of the quartz plate 20 during processing. The mold M0 has a through-hole M11 for decompression formed in the bottom surface of the recess M1. The cooling body C0 includes a fitting portion C1 into which the mold M0 is fitted and an exhaust port C11 on the bottom surface of the fitting portion C1, and serves to cool the mold M0 when processing the quartz plate 20. The quartz plate 20 is positioned to cover the entire recess M1 of the mold M0.

[0053] Next, as shown in FIG. 6B , a flame F is blown from a torch T toward the quartz plate 20 to melt the quartz plate 20. At this time, a vacuum is applied to the recess M1 of the mold M0 through the exhaust port C11 of the cooling body C0 by a vacuum mechanism (not shown). As a result, the melted portion of the quartz plate 20 is stretched toward the bottom of the recess M1, and its central peripheral region is supported by the support portions M2. After that, by stopping the heating of the quartz plate 20 and allowing it to cool, the quartz plate 20 is formed with a curved portion 201 having a substantially hemispherical three-dimensional curved shape and a recessed portion 202 that is recessed near the center of the curved portion 201 and follows the outline of the protrusion M21. Furthermore, the portion of the quartz plate 20 located outside the recess M1 is located at the outer peripheral edge of the curved portion 201, forming a flat edge portion 203.

[0054] Next, the recess M1 of the mold M0 is returned to normal pressure, the processed quartz plate 20 is removed, and the quartz plate 20 is sealed with a sealing material E made of any curable resin material, as shown in FIG. 6C, for example. Thereafter, for example, the sealing material E is polished and CMP (short for Chemical Mechanical Polishing) is performed from the surface on the edge 203 side to the portion shown by the dashed dotted line in FIG. 6C, and the edge 203 is removed together with the sealing material E. As a result, the quartz plate 20 has a shape having a curved surface portion 21 with an annular curved surface and a connection portion 22 recessed from the vertex of the curved surface portion 21.

[0055] Then, the sealing material E is completely removed by any method such as heating or dissolving with a chemical solution, and the quartz plate 20 is taken out. Finally, surface electrodes 23 are formed on both the front and back surfaces of the processed quartz plate 20 by a film formation process such as sputtering or vapor deposition. The surface electrodes 23 may be patterned by a known method such as using a mask (not shown) as needed.

[0056] The micro-vibrator 2 is manufactured by, for example, the manufacturing process described above, but is not limited to this example manufacturing method. For example, the heat source for melting the quartz plate 20 shown in Fig. 6B may be a heater capable of heating the quartz plate 20 over an area equivalent to that when the flame F is used, instead of the flame F from the torch T. In this way, the manufacturing process for the micro-vibrator 2 may be changed as appropriate, and other known methods may also be adopted.

[0057] Furthermore, the micro-vibrator 2 has a roughly half-toroidal shape that is rotationally symmetric with the Z direction as the rotation axis, but is not limited to the BR shape shown in the figure, as long as the curved surface portion 21 has a three-dimensional, bowl-like curved surface shape and is capable of vibrating in wine glass mode. For example, the connecting portion 22 may be a cylindrical recess with a bottom, or may be a columnar shape. BR stands for Bird-bath Resonator.

[0058] Next, a process for forming the mounting substrate 3 and a process for mounting the micro-vibrator 2 will be described. Note that Figures 8A to 8F, which will be described later, show cross sections corresponding to Figure 3. Also, Figures 9A to 9F, which will be described later, show cross sections corresponding to Figure 4. Furthermore, Figures 8A and 9A, Figures 8B and 9B, Figures 8C and 9C, Figures 8D and 9D, Figures 8E and 9E, and Figures 8F and 9F each show the same process.

[0059] First, an insulating glass substrate that will become the lower substrate 4 is prepared, and after forming a groove 41 by etching as shown in FIG. 7A, wiring 42 and a conductive layer 43 are formed by sputtering or the like using a mask not shown.

[0060] Next, as shown in FIG. 7B, for example, an upper substrate 5 made of conductive silicon or the like is prepared and anodic bonded to the surface of the lower substrate 4 on which the grooves 41 and the like are formed.

[0061] 7C, trench etching is then performed on the upper substrate 5 by DRIE or the like to partially expose the lower substrate 4 and separate the region including the plurality of second base portions 532, which are components of the plurality of first electrode portions 53 to be formed later, from the other region of the upper substrate 5. DRIE is an abbreviation for Deep Reactive Ion Etching.

[0062] Then, as shown in FIG. 7D, an insulating film 533 made of TEOS is formed by, for example, plasma CVD to cover the upper substrate 5 and the portions of the lower substrate 4 that are exposed from the upper substrate 5.

[0063] Next, for example, a resist film (not shown) having a predetermined pattern is formed by photolithography, and dry etching is performed to remove a portion of the insulating film 533, and then the resist film (not shown) is removed. As a result, as shown in Fig. 8A, for example, a contact hole 533a is formed that exposes a portion of the region that will become the second base portion 532 in the insulating film 533 covering the upper substrate 5, and a region of the upper substrate 5 that will later become the second electrode portion 54 is exposed from the insulating film 533. At this time, the region that will become one surface 532a of the second base portion 532 other than the region where the extraction electrode 535 is to be formed is covered with the insulating film 533, as shown in Fig. 9A, for example.

[0064] Subsequently, sputtering or the like is performed using a mask (not shown) to form a metal film M that covers the upper substrate 5 and the insulating film 533, as shown in, for example, FIG. 8B and FIG. 9B.

[0065] Thereafter, the metal film M is patterned by, for example, photolithography etching, to separate the portion of the metal film M exposed from the insulating film 533 of the upper substrate 5 from the portion covering the insulating film 533, making them electrically independent. As a result, as shown in, for example, FIGS. 8C and 9C , an electrode pad 542 covering what will later become the second electrode portion 54, a guard electrode 534 covering the portion that will become the first base portion 531, and an extraction electrode 535 covering part of the second base portion 532 are formed. The electrode pad 542, the guard electrode 534, and the extraction electrode 535 are electrically insulated from the portion of the metal film M covering the insulating film 533. At this time, the portion of the metal film M covering the insulating film 533 is left, for example, on the regions that will later become the inner frame portion 51 and the first base portion 531, and on the portion that straddles the first base portion 531 and the second base portion 532.

[0066] Then, for example, as shown in Figures 8D and 9D, the portions of the insulating film 533 exposed from the metal film M, except for the areas near the extraction electrode 535 and the electrode pad 542, are removed by dry etching or the like in the same manner as described above, to expose a portion of the upper substrate 5.

[0067] Next, as shown in Figures 8E and 9E, unnecessary portions of upper substrate 5 are removed by trench etching such as DRIE to expose portions of lower substrate 4, and inner frame portion 51 is separated from first base portion 531 that constitutes first electrode portion 53. This results in mounting substrate 3 having grooves 41, wiring 42, first electrode portion 53, and second electrode portion 54.

[0068] Next, for example, the mounting substrate 3 is suction-fixed to a mounter device (not shown), and a bonding member 52 is placed in the region of the mounting substrate 3 surrounded by the inner frame portion 51. Then, for example, the micro-vibrator 2 is transported by a transport device (not shown), the mounting surface 22b of the connection portion 22 is brought into contact with the bonding member 52, and the bonding member 52 is solidified, thereby mounting the micro-vibrator 2. For example, the micro-vibrator 2 can be transported by bringing a vacuum-suction-capable gripping mechanism of a transport device (not shown) into contact with the suction surface 22a of the micro-vibrator 2 and performing vacuum suction. Furthermore, the mounting substrate 3 is heated by a heating mechanism of the mounter device (not shown), and the micro-vibrator 2 is cooled after being mounted, and the bonding member 52 is solidified, thereby bonding the micro-vibrator 2 to the mounting substrate 3.

[0069] The alignment of the micro-vibrator 2 with respect to the mounting substrate 3 can be achieved, for example, by capturing images of the micro-vibrator 2 and the mounting substrate 3 and extracting feature points by edge detection using a known image processing technique, thereby adjusting the relative position.

[0070] Thereafter, as shown in, for example, FIG. 8F and FIG. 9F, wires W are connected to the guard electrode 534, the extraction electrode 535, and the electrode pad 542 by wire bonding.

[0071] Through the above steps, an inertial sensor having the mounting structure 1 of this embodiment can be manufactured.

[0072] According to this embodiment, the upper surface 531b of the first base portion 531 of the first electrode portion 53 that faces the rim 211 of the micro-vibrator 2 is covered by the guard electrode 534, resulting in a mounting structure 1 that can shield electric lines of force that extend from the upper surface 531b to the upper side surface of the rim 211. Therefore, this mounting structure 1 reduces noise caused by surfaces of the plurality of first electrode portions 53 other than the opposing surface 531a that faces the micro-vibrator 2, thereby achieving the effect of improving the detection accuracy of the capacitance.

[0073] (Second embodiment) The mounting structure 1 of the second embodiment will be described with reference to the drawings.

[0074] 10, when viewed from above, the invisible portions of the micro-vibrator 2 and the outer periphery of the mounting substrate 3 are indicated by dashed lines. This also applies to FIGS. 13 and 14, which will be described later.

[0075] 10, the mounting structure 1 of this embodiment has a configuration in which at least one guard electrode 55 is arranged between adjacent first electrode portions 53 of a mounting substrate 3. Furthermore, the mounting substrate 3 has a shape in which the portions of the multiple first electrode portions 53 facing the rim 211 become wider as they approach the rim 211 in top view. The mounting structure 1 of this embodiment differs from the first embodiment in the above points. This difference will be mainly described in this embodiment.

[0076] In this embodiment, the multiple first electrode portions 53 have only a first base portion 531 as a base portion, and do not have a second base portion 532. The multiple first electrode portions 53 have a facing portion 5311 that faces the rim 211, a narrow portion 5312 connected to the facing portion 5311, and a terminal portion 5313 connected to the end of the narrow portion 5312 on the opposite side to the facing portion 5311. In other words, in this embodiment, the base portion 531 is composed of the facing portion 5311, the narrow portion 5312, and the terminal portion 5313.

[0077] 11, the facing portion 5311 is a portion having a facing surface 531a facing the rim 211. For example, the facing portion 5311 has a substantially triangular shape when viewed from above, with the width of the end portion on the rim 211 side being wider than the end portion on the narrow width portion 5312 side, and the width of the end portion on the narrow width portion 5312 side being the smallest. As a result, the area of ​​the portion of the upper surface 531b of the first electrode portion 53 that corresponds to the facing portion 5311 is smaller than in a case where the first electrode portion 53 does not have the narrow width portion 5312, and it is possible to reduce the influence of the electric field lines caused by the upper surface 531b of the facing portion 5311.

[0078] The narrow portion 5312 connects the facing portion 5311 and the terminal portion 5313, and is the portion of the first electrode portion 53 that has the narrowest width when viewed from above.

[0079] The terminal portion 5313 is a wire connection region where an extraction electrode 535 to which a wire (not shown) is connected is formed on the upper surface 531b.

[0080] In this embodiment, at least one guard electrode 55 is formed between adjacent first electrode portions 53 on the mounting substrate 3. For example, the guard electrodes 55 are arranged alternately with the first electrode portions 53, but this is not limiting. The guard electrodes 55 are made of the same material as the first base portions 531 of the first electrode portions 53 and are portions separated from the electrode portions 53, 54 by etching the silicon substrate that constitutes the upper substrate 5. The guard electrodes 55 are arranged at a distance from the first electrode portion 53 and the second electrode portion 54 and are electrically independent from them. As shown in FIGS. 10 and 11 , each of the guard electrodes 55 has a terminal electrode 551 to which a wire (not shown) is connected on the upper surface opposite the mounting substrate 3.

[0081] The shape, number, arrangement, etc. of the multiple guard electrodes 55 may be changed as appropriate as long as they are not in contact with the multiple first electrode portions 53 and second electrode portions 54. The distance between the multiple guard electrodes 55 and adjacent first electrode portions 53 may be adjusted as needed when viewed from above. For example, the guard electrodes 55 may be arranged so that a first distance from a drive electrode of the first electrode portion 53 that drives the micro-vibrator 2 is relatively larger than a second distance from a detection electrode of the first electrode portion 53 that detects the electrostatic capacitance with the micro-vibrator 2.

[0082] According to the present embodiment, the area of ​​the portion of the upper surfaces 531b of the multiple first electrode portions 53 that faces the rim 211 is relatively smaller than in a case where there is no narrow portion 5312, resulting in a mounting structure 1 that reduces the influence of electric lines of force directed toward the upper side surface of the rim 211. Therefore, this mounting structure 1 can reduce noise caused by surfaces other than the facing surfaces 531a of the first electrode portions 53.

[0083] (Modification of the second embodiment) 12, the mounting structure 1 of the second embodiment may have a configuration in which an insulating film 533 and a guard electrode 534 are laminated on the upper surfaces 531b, 55a of the plurality of first electrode portions 53 and guard electrodes 55, respectively. In this case, the guard electrode 55 serves as the first guard electrode, and the guard electrode 534 formed on the plurality of first electrode portions 53 functions as the second guard electrode. In this case, a first contact hole 533b is formed in a portion of the insulating film 533 that is formed on the upper surfaces 531b of the first electrode portions 53, and an extraction electrode 535 is formed inside the first contact hole 533b. In addition, a second contact hole 533c is formed in a portion of the insulating film 533 that covers the upper surface 55a of the guard electrode 55, and a terminal electrode 551 is formed inside the second contact hole 533c.

[0084] Some of the multiple guard electrodes 55 may be used as drive electrodes or capacitance detection electrodes for the micro-vibrator 2. In this case, it is preferable that at least the guard electrodes 55 used as capacitance detection electrodes have a portion facing the rim 211 that is wider the closer to the rim 211 and narrower the farther away from the rim 211, similar to the facing portion 5311. In this case, the first electrode portion 53 adjacent to the first guard electrode 55 used as a detection electrode and the second guard electrode 534 provided on its upper surface 531b suppress the fringe effect and reduce noise.

[0085] The second guard electrode 534 may be structurally and electrically connected to some or all of the other first electrode portions 53 or other second guard electrodes 534 arranged on the first guard electrode 55.

[0086] Furthermore, the multiple second guard electrodes 534 may be used as drive electrodes instead of the first base portion 531 of the first electrode portion 53. In this case, an electrostatic attractive force is generated that pulls a portion of the rim 211 of the micro-vibrator 2 that is located below the second guard electrode 534 in the z direction obliquely upward toward the second guard electrode 534, making it possible to change the drive vibration mode of the micro-vibrator 2. In this case, for example, the first base portion 531 of the first electrode portion 53 is used as a detection electrode.

[0087] This modification also provides the mounting structure 1 with the same effects as those of the second embodiment. In this modification, the upper surface 531b of the first electrode portion 53 is covered with the second guard electrode 534, and the second guard electrode 534 shields the electric field lines directed from the upper surface 531b toward the upper side surface of the rim 211, thereby making it possible to further reduce noise caused by surfaces other than the opposing surface 531a.

[0088] (Other embodiments) Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, various combinations and forms, as well as other combinations and forms including only one element, more than one, or less than one, are also within the scope and spirit of the present disclosure.

[0089] (1) In the above-described embodiments and their modified examples, the mounting substrate 3 is configured to have the groove 41 for preventing contact with the rim 211 of the micro-vibrator 2. However, the present invention is not limited to this example. For example, if the rim 211 of the micro-vibrator 2 is configured to be higher in the z direction than the mounting surface 22b, i.e., if the mounting surface 22b protrudes more than the rim 211, the mounting substrate 3 may not have the groove 41.

[0090] (2) In the first embodiment, the guard electrode 534 covering the upper surfaces 531b of the plurality of first electrode portions 53 may be electrically connected to some or all of the guard electrodes 534 of the other first electrode portions 53. In this case, the mounting substrate 3 may have a substantially annular peripheral wiring 44 located on the outer periphery of the plurality of first electrode portions 53, as shown in FIG. 13 , for example. The peripheral wiring 44 may be formed, for example, using the same conductive material as the guard electrode 534 in the same process, and may be integral with the guard electrode 534. In addition, an insulating layer (not shown) formed integrally with the insulating film 533 is formed directly below the peripheral wiring 44, and the peripheral wiring 44 is electrically independent from other wiring such as the bridge wiring 42. The peripheral wiring 44 may be formed so as to straddle the bridge wiring 42 as shown in FIG. 13 , or may be formed in an area other than the plurality of bridge wirings 42 and connect some of the guard electrodes 534 of the plurality of first electrode portions 53. The arrangement of the peripheral wiring 44 may be modified as appropriate.

[0091] Furthermore, the guard electrode 534 may be, for example, annular in shape together with the insulating film 533 in top view, and may be integrated with the guard electrodes 534 of the multiple first electrode portions 53 without using the peripheral wiring 44. In other words, the multiple first electrode portions 53 may be configured to be covered by one common guard electrode 534.

[0092] (3) In the second embodiment, the multiple guard electrodes 55 may be connected in a region closer to the outer periphery than the multiple first electrode portions 53, as shown in Fig. 14, for example. In this case, at least one terminal electrode 551 may be formed for each guard electrode 55, and the number and arrangement thereof may be changed as appropriate. Furthermore, the multiple first electrode portions 53 may have a reduced area of ​​the terminal portion 5313 to ensure a connection region for the multiple guard electrodes 55.

[0093] (4) In the first embodiment, the micro-vibrator 2 may have a configuration in which the surface electrode 23 is formed only on the back surface 2b, as shown in Fig. 15. This also applies to the second embodiment and its modified examples. In this case, the surface 2a of the micro-vibrator 2 is exposed to the outside, and the area covered by the surface electrode 23 is reduced, thereby improving the Q value.

[0094] (5) In the first embodiment, the plurality of first electrode units 53 may not have a second base unit 532, but may have an insulating film 533 and a guard electrode 534 stacked on a first base unit 531, as shown in Fig. 16, for example. In this case, the plurality of first electrode units 53 have an extraction electrode 535 formed on a portion of the upper surface 531b that is exposed from the insulating film 533.

[0095] (6) In each of the above embodiments and their modified examples, when a covering material also called a lid is attached to the mounting structure 1, a configuration may be adopted in which an electrode is separately provided on the inside of the covering material for controlling the drive vibration mode of the micro-vibrator 2. In this case, an effect is obtained in which the drive vibration mode of the micro-vibrator 2 can be controlled to a desired one while reducing noise caused by the first electrode portion 53 of the mounting substrate 3.

[0096] (7) In the above embodiments and their modified examples, the mounting substrate 3 has been described as having 16 first electrode portions 53, but this is not limited thereto. For example, the mounting substrate 3 may have a plurality of first electrode portions 53, preferably four or more first electrode portions 53, and the number may be changed appropriately depending on the outer diameter of the micro-vibrator 2, etc. For example, in the case where the mounting substrate 3 has four first electrode portions 53, two of the first electrode portions 53 are detection electrodes and the remaining two first electrode portions 53 are drive electrodes.

[0097] (8) In each of the above embodiments and their modified examples, the number, arrangement, shape, etc. of the second electrode portion 54 of the mounting substrate 3 may be changed as appropriate as long as at least one second electrode portion 54 is arranged and is electrically independent from the multiple first electrode portions 53. For example, the second electrode portion 54 may be in the form of a single frame surrounding the multiple first electrode portions 53, or may be in the form of a frame made up of multiple divided members.

[0098] (9) In the first embodiment described above, the upper surface of the inner frame portion 51 of the mounting substrate 3 is covered with the insulating film 533 and a metal film made of the same material as the guard electrode 534, but the upper surface may be configured without the insulating film 533 and the metal film.

[0099] (10) The mounting structure 1 of each of the above embodiments and its modified examples can also control the drive mode, such as scalar driving the micro-vibrator 2, by applying the same drive signal to all of the guard electrodes 534 or 55. Scalar driving is also called "parametric excitation" or "self-excited vibration."

[0100] (11) It goes without saying that in each of the above embodiments, the elements constituting the embodiment are not necessarily essential unless they are specifically stated as essential or are clearly considered essential in principle. Furthermore, in each of the above embodiments, when the number, numerical value, amount, range, or other numerical value of the components of the embodiment is mentioned, it is not limited to that specific number unless it is specifically stated as essential or is clearly limited to a specific number in principle. Furthermore, in each of the above embodiments, when the shape, positional relationship, etc. of the components, etc. are mentioned, it is not limited to that shape, positional relationship, etc. unless it is specifically stated or is clearly limited to a specific shape, positional relationship, etc. in principle. [Explanation of symbols]

[0101] 2... Micro-vibrator, 21... Curved surface portion, 211... Rim, 22... Connection portion 22b: Mounting surface; 23: Surface electrode; 3: Mounting board; 42: Wiring 43... Conductive layer, 53... Electrode part, 531... First base, 531a... Opposing surface 531b: Upper surface 5311: Opposing portion, 5312: Narrow portion 5313...Terminal section, 532...Second base, 532a...One side 533....Insulating film 533a, 533b, 533c... (insulating film) contact holes 534 Guard electrode, 535 Extraction electrode, 55 Guard electrode 551...terminal electrode

Claims

1. A mounting structure for a micro-vibrator, a micro-vibrator (2) having a curved surface portion (21) having an annular curved surface and a connecting portion (22) extending from the curved surface portion to the center of the inside of the curved surface portion; a mounting substrate (3) having a rim (211) at an end of the curved surface portion opposite the connection portion, and a plurality of electrode portions (53) facing the rim and surrounding the rim and arranged at a distance from each other, the micro-vibrator is in a hollow state in which the connecting portion is joined to the mounting substrate and the curved surface portion is not in contact with other members, The plurality of electrode portions are a base (531) having an opposing surface (531a) facing the rim, an insulating film (533) covering a surface of the base different from the opposing surface, including at least an upper surface (531b) opposite the mounting substrate, and a guard electrode (534) formed on the insulating film, covering at least the upper surface, and electrically independent of the base.

2. The plurality of electrode portions further include a second base portion (532) disposed on the opposite side of the rim with the base portion as a first base portion, and the second base portion has the insulating film and the guard electrode laminated in this order on at least one surface (532a) opposite to the mounting substrate, and is electrically connected to the first base portion by a conductive layer (43); 2. The micro-vibrator mounting structure according to claim 1, wherein the guard electrode is electrically independent from the second base portion.

3. 3. The micro-vibrator mounting structure according to claim 2, wherein the second base portion is made of the same material as the first base portion.

4. the insulating film has a contact hole (533a) that exposes a part of the one surface of the second base portion; 4. The micro-vibrator mounting structure according to claim 3, wherein an extraction electrode (535) electrically independent from the guard electrode is formed inside the contact hole, covering the portion of the second base exposed from the insulating film.

5. A mounting structure for a micro-vibrator, a micro-vibrator (2) having a curved surface portion (21) having an annular curved surface and a connecting portion (22) extending from the curved surface portion to the center of the inside of the curved surface portion; a mounting substrate (3) having a rim (211) at an end of the curved surface portion opposite the connection portion, and a plurality of electrode portions (53) and a plurality of guard electrodes (55) facing the rim and surrounding the rim and arranged at a distance from each other; the micro-vibrator is in a hollow state in which the connecting portion is joined to the mounting substrate and the curved surface portion is not in contact with other members, At least one of the guard electrodes is disposed between adjacent electrode portions, The plurality of electrode portions each include a base (531) having a facing portion (5311) that faces the rim, a terminal portion (5313) that is disposed on the opposite side of the rim from the facing portion, and a narrow portion (5312) that connects the facing portion and the terminal portion and has a width narrower than the facing portion and the terminal portion; A micro-vibrator mounting structure, wherein the width of the opposing portion at the end on the rim side is larger than the width of the end on the narrow width side, and the width of the end on the narrow width side is the smallest.

6. 6. The micro-vibrator mounting structure of claim 5, wherein the plurality of guard electrodes are first guard electrodes, and the plurality of electrode portions are on a surface different from an opposing surface facing the rim, and include an insulating film covering at least a portion including an upper surface opposite the mounting substrate, and a second guard electrode formed on the insulating film, covering at least the upper surface, and being electrically independent from the base.

7. the insulating film also covers at least upper surfaces (55a) of the plurality of first guard electrodes opposite to the mounting substrate, and has first contact holes (533b) that expose portions of the upper surfaces of the plurality of electrode portions, and second contact holes (533c) that expose portions of the upper surfaces of the plurality of first guard electrodes; an extraction electrode (535) electrically independent from the second guard electrode is formed inside the first contact hole, the extraction electrode covering the portions of the plurality of electrode portions exposed from the insulating film; 7. The micro-vibrator mounting structure according to claim 6, wherein a terminal electrode (551) is formed inside the second contact hole to cover the portions of the plurality of first guard electrodes that are exposed from the insulating film.

8. The micro-vibrator has a surface electrode (23) that covers the rim and a mounting surface (22b) of the connection portion that faces the mounting substrate, The mounting substrate has wiring (42) electrically independent from the plurality of electrode portions, 8. The micro-vibrator mounting structure according to claim 1, wherein the surface electrode is electrically connected to the wiring.

Images