JP7679753B2 - Inertial Sensors - Google Patents

Description

The present invention relates to an inertial sensor equipped with a micro-vibrator and a method for manufacturing the same.

In recent years, autonomous driving systems for vehicles have been developed, and this type of system requires highly accurate self-location estimation technology. For example, for so-called level 3 autonomous driving, a self-location estimation system equipped with a GNSS (short for Global Navigation Satellite System) and an IMU (short for Inertial Measurement Unit) is being developed. The IMU is, for example, a six-axis inertial force sensor consisting of 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 the current system will be required.

As a gyro sensor for realizing such a high-sensitivity IMU, for example, BRG (short for Bird-bath Resonator Gyroscope) is considered to be a promising candidate. BRG is configured by mounting a micro-vibrator having a three-dimensional curved surface that vibrates in wine glass mode on a mounting board (for example, Patent Document 1). This micro-vibrator has a Q value that represents the vibration state of ¹⁰⁶ or more, so it is expected to have higher sensitivity than conventional ones.

US Patent Application Publication No. 2019/0094024

As described in Patent Document 1, for example, this micro-vibrator is formed by setting a plate material that can be subjected to a reflow process by heating, such as quartz, in a mold, melting it, and solidifying it to form a three-dimensional curved surface that vibrates in wine glass mode. After covering the plate material after the above processing with a sealing material, unnecessary parts are removed by polishing or CMP (short for Chemical Mechanical Polishing), etc., resulting in a structure having a mounting part that is bonded to the mounting board and a three-dimensional shape part that becomes hollow when mounted on the mounting board. In addition, this micro-vibrator has electrode films that cover the front and back surfaces, and is arranged at a distance from multiple electrodes formed on the mounting board on which it is mounted, forming a capacitor with these.

In the BRG described in Patent Document 1, a micro-vibrator (BR) that serves as a resonator is mounted on a mounting board having multiple electrode parts arranged in a ring at a distance from each other, and the rim of the BR is made hollow. However, when this BRG is manufactured, the mounting part of the micro-vibrator may be inclined relative to the mounting surface of the mounting board, and the micro-vibrator may be joined in an inclined state relative to the mounting board. In this case, the area of the rim of the micro-vibrator that faces the multiple electrode parts varies depending on the location. This causes variation in the electrostatic capacitance of each capacitor composed of the BR and the multiple electrode parts in the BRG, reducing the sensor accuracy.

In view of the above, the present invention aims to suppress the variation in the area of the rim of the micro-vibrator arranged opposite multiple electrode portions of the mounting substrate in an inertial sensor in which a micro-vibrator that vibrates in wine glass mode is mounted on a mounting substrate, thereby improving the sensor accuracy.

In order to achieve the above object, the inertial sensor according to claims 1 to 3 is an inertial sensor comprising a micro-vibrator (2) which is a thin-walled member having a front surface (2a) which is a surface on the side with a larger outer diameter and a back surface (2b) which is the opposite surface to the front surface, the micro-vibrator (2) having a curved surface portion (21) with an annular curved surface and a bottomed cylindrical recess (22) recessed from the curved surface portion to the back surface side, an upper substrate (5) having a frame-shaped inner frame portion (51) and a plurality of electrode portions (53) arranged to surround the inner frame portion while being spaced apart from each other, the upper substrate (5) being joined to a lower substrate (4). and a bonding member (52) that is arranged in an inner region of the mounting substrate that is surrounded by an inner frame portion, and the micro-vibrator has a mounting surface (22b) that is the bottom surface of the back surface side of the recess that is arranged in the inner region and bonded to the mounting substrate via the bonding member, a rim (211) that is a partial region of the curved portion that includes the end portion opposite the recess is hollow, and a rim underside (211c) that is a surface of the rim that connects the front surface and the back surface is located on the same plane as the mounting surface or the tip portion (28).
In the inertial sensor described in claim 1, the micro-vibrator has, on its mounting surface, a mounting surface recess (26) recessed from the back surface toward the front surface, and a protrusion (27) protruding from the mounting surface recess toward the mounting surface, and the mounting board has a positioning groove (43) corresponding to the protrusion, and the protrusion is inserted into the positioning groove.
In the inertial sensor described in claim 2, the micro-vibrator is provided on a side surface of the recess near the bottom surface of the front surface, and has a side through hole (24) connecting the front surface and the back surface, and at least a portion of the joining member penetrates into the side through hole.
In the inertial sensor according to the third aspect of the present invention, the micro-vibrator has a bottom surface through-hole (25) provided on the mounting surface, and at least a portion of the bonding member fits into the bottom surface through-hole.

According to this, a micro-vibrator having a curved surface portion having a three-dimensional curved surface and a recess recessed from the curved surface portion is bonded to a mounting substrate, and a rim, which is a region of the curved surface portion including the end portion opposite the recess, is in a hollow state. In this inertial sensor, the mounting surface of the micro-vibrator in the recess where it is bonded to the mounting substrate or its tip portion and the rim underside connecting the front and back surfaces of the rim are located on the same plane. Therefore, even when the micro-vibrator is tilted with respect to the mounting substrate, the mounting surface and the rim underside are located at the same height, so that the positional variation in the height direction of the rim with respect to the multiple electrodes of the mounting substrate, i.e., the area variation of the rim arranged opposite to the mounting substrate, is reduced. Therefore, in this inertial sensor, even when the micro-vibrator is tilted with respect to the mounting substrate, the capacitance variation of the capacitor formed by the micro-vibrator and the multiple electrodes of the mounting substrate is suppressed, improving the sensor accuracy.

A manufacturing method of an inertial sensor according to claim 6 is a manufacturing method of an inertial sensor in which a micro-vibrator (2) is a thin-walled member having a front surface (2a) which is a surface with a larger outer diameter and a back surface (2b) which is the opposite surface to the front surface, the micro-vibrator having a curved surface portion (21) having an annular curved surface and a cylindrical recessed portion (22) with a bottom recessed from the curved surface portion to the back surface side, and a mounting substrate (3) in which an upper substrate (5) having a frame-shaped inner frame portion (51) and a plurality of electrode portions (53) arranged to surround the inner frame portion while being spaced apart from each other, is joined to a lower substrate (4) via a joining member (52), the manufacturing method comprising the steps of: preparing a micro-vibrator; arranging the joining member in an inner region of the mounting substrate surrounded by the inner frame portion; and, after arranging the joining member, arranging the recessed portion of the micro-vibrator in the inner region and bringing the mounting surface (22b), which is the bottom surface of the recessed portion on the back surface side, into contact with the joining member. and melting and then solidifying the bonding material to bond the micro-vibrator and the mounting board, and making the rim (211), which is the end of the curved portion of the micro-vibrator opposite the recess, hollow. In preparing the micro-vibrator, a thin-walled base material (20) on the order of micrometers is heated and melted and solidified to form a curved portion (201) that will later become the curved portion, and a recessed portion (202) that will later become the recess, and then the thin-walled base material is sealed with a sealing material (E). The curved portion, the recessed portion, and part of the sealing material are polished away to form a mounting surface and a rim underside (211c) that connects the front and back surfaces of the rim, which are located on the same plane . Through holes (24, 25) are formed on or near the mounting surface. In making the rim hollow, part of the molten bonding material is poured into the through holes .

According to this, the method for manufacturing an inertial sensor includes heating and melting a thin-walled substrate, solidifying it to form curved portions and recessed portions, and polishing it to form a micro-vibrator having a mounting surface and a rim underside located on the same plane. Because the mounting surface and the rim underside of the micro-vibrator are located on the same plane, even if the micro-vibrator is tilted when bonding the micro-vibrator to the mounting board, the variation in the area of the rim that is placed opposite the multiple electrode portions of the mounting board is reduced. Therefore, the variation in the electrostatic capacitance of the capacitor formed by the micro-vibrator and the multiple electrode portions of the mounting board is suppressed, and an inertial sensor with improved sensor accuracy can be manufactured.

A manufacturing method of an inertial sensor according to a seventh aspect of the present invention is a manufacturing method of an inertial sensor in which a micro-vibrator (2) is a thin-walled member having a front surface (2a) which is a surface with a larger outer diameter and a back surface (2b) which is the opposite surface to the front surface, the micro-vibrator (2) having a curved surface portion (21) with an annular curved surface, a cylindrical recess (22) with a bottom recessed from the curved surface portion to the back surface side, and a through hole (25) formed in a mounting surface (22b) which is the bottom surface of the recess, and a mounting board (3) formed by bonding an upper substrate (5) having a frame-shaped inner frame portion (51), a plurality of electrode portions (53) arranged to surround the inner frame portion while being spaced apart from each other, and support portions (55) arranged in an area surrounded by the inner frame portion to a lower substrate (4) via a bonding member (52), the manufacturing method comprising the steps of: preparing a micro-vibrator; The process includes inserting the support portion of the substrate and placing the micro-vibrator on the mounting substrate; and after placing the micro-vibrator on the mounting substrate, pouring a bonding material into the recess and solidifying it to bond the micro-vibrator to the mounting substrate, and making a rim (211), which is the end of the curved portion of the micro-vibrator opposite the recess, hollow. In preparing the micro-vibrator, a thin-walled base material (20) on the order of micrometers is heated, melted, and solidified to form a curved portion (201) that will later become the curved portion, and a recessed portion (202) that will later become the recess, and then sealing the thin-walled base material with a sealing material (E). The curved portion, the recessed portion, and part of the sealing material are polished away to form the mounting surface and the rim underside (211c) that connects the front and back surfaces of the rim, which are located on the same plane.

According to this, as with the inertial sensor manufacturing method described in claim 7, in addition to the mounting surface and the rim underside being located on the same plane, a micro-vibrator having a through hole is formed on the mounting surface. Meanwhile, a mounting substrate is prepared that has a support portion that is inserted into the through hole formed on the mounting surface of the micro-vibrator. Then, after inserting and placing the support portion of the mounting substrate into the through hole of the micro-vibrator, a bonding material is poured into the recess of the micro-vibrator and solidified to bond the micro-vibrator to the mounting substrate. Even after such a bonding process, since the mounting surface and the rim underside are located on the same plane, the capacitance variation of the capacitor formed by the micro-vibrator and the multiple electrodes of the mounting substrate is suppressed, and an inertial sensor with improved sensor accuracy can be manufactured.

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.

FIG. 2 is a top view showing the layout of the inertial sensor according to the first embodiment. FIG. 2 is a perspective view showing a micro-vibrator used in the inertial sensor. FIG. 3 is a cross-sectional view showing a cross-sectional configuration taken along line III-III in FIG. 2 . 11A to 11C are diagrams showing a process of preparing a member in a process of forming a micro-vibrator. FIG. 4B is a diagram showing a process following FIG. 4A. FIG. 4C is a diagram showing a process following FIG. 4B. FIG. 4D is a diagram showing a process following FIG. 4C. 3 is a top view of a layout showing a mounting substrate on which the microvibrator of FIG. 2 is mounted. 6 is a cross-sectional view showing a cross-sectional configuration taken along line VI-VI in FIG. 5 . FIG. 7 is a cross-sectional view showing a cross-sectional configuration taken along line VII-VII in FIG. 5 . FIG. 2 is a cross-sectional view showing a cross-sectional configuration taken along line VIII-VIII in FIG. 1 . FIG. 2 is a cross-sectional view showing a cross-sectional configuration taken along line IX-IX in FIG. 1 . FIG. 11 is a cross-sectional view showing a micro-vibration body of a comparative example. 10B is a cross-sectional view showing a cross-sectional configuration of an inertial sensor of a comparative example in which the micro-vibrator of FIG. 10A is mounted on a mounting substrate. 10A to 10C are diagrams showing a step of mounting a micro-vibrator in the manufacture of an inertial sensor, and are diagrams showing a step of preparing a member. FIG. 11B is a diagram showing a process following FIG. 11A. FIG. 11B is a diagram showing a process following FIG. FIG. 11D is a diagram showing a process following FIG. FIG. 11D shows a step following FIG. FIG. 11 is a cross-sectional view showing a modified example of the micro-vibrator of the inertial sensor of the first embodiment. FIG. 4 is a cross-sectional view showing a modified example of the inertial sensor of the first embodiment. FIG. 11 is a cross-sectional view showing an inertial sensor according to a second embodiment. FIG. 11 is a cross-sectional view showing a micro-vibrator in an inertial sensor according to a second embodiment. FIG. 11 is a cross-sectional view showing an inertial sensor according to a third embodiment. FIG. 11 is a cross-sectional view showing a micro-vibrator in an inertial sensor according to a third embodiment. 13A to 13C are explanatory views for explaining an example of a method for forming a bottom surface through hole in the third embodiment. FIG. 13 is a top view showing a layout of a modified example of the inertial sensor of the third embodiment. FIG. 13 is a top view showing a layout of a mounting board according to a modified example of the inertial sensor of the third embodiment. FIG. 20 is a cross-sectional view showing a cross-sectional configuration taken along line XXI-XXI of FIG. 19 . FIG. 13 is a cross-sectional view showing an inertial sensor according to a fourth embodiment. FIG. 13 is a cross-sectional view showing a micro-vibrator in an inertial sensor according to a fourth embodiment. FIG. 13 is a top view showing a layout of a mounting board for the inertial sensor according to the fourth embodiment. 23 is a diagram showing a member preparation step in the molding process of the micro-vibration body shown in FIG. 22. FIG. 24B is a diagram showing a process following FIG. 24A. FIG. 13 is a cross-sectional view showing a micro-vibrator according to a modified example of the inertial sensor of the fourth embodiment. FIG. 13 is a top view showing a layout of a mounting board according to a modified example of the inertial sensor of the fourth embodiment. FIG. 13 is a cross-sectional view showing a modified example of the inertial sensor of the fourth embodiment. FIG. 13 is a cross-sectional view showing another modified example of the inertial sensor of the fourth embodiment. 30 is a diagram showing a step of mounting a micro-vibrator in the manufacture of the inertial sensor of FIG. 29, and is an explanatory diagram for explaining a step of placing the micro-vibrator on a mounting substrate and a subsequent step of filling with a bonding material. FIG. 11A and 11B are cross-sectional views showing other examples of the shape of the micro-vibrator.

The following describes embodiments of the present invention with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are denoted by the same reference numerals.

First Embodiment
An inertial sensor 1 according to an embodiment will be described with reference to FIGS.

In FIG. 2, in order to make it easier to understand the configuration of the micro-vibrator 2 described later, a portion of the micro-vibrator 2 is omitted to show the cross section, and the portion of the outer periphery of the micro-vibrator 2 that cannot be seen from the angle shown in FIG. 2 is shown by dashed lines.

For ease of explanation, the direction along the left-right direction on the paper as shown in FIG. 1 will be referred to as the "x-direction", the direction perpendicular to the x-direction on the paper as the "y-direction", and the normal direction to the xy plane as the "z-direction". The x, y, and z directions in FIG. 3 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 opposite side to the top. Furthermore, in this specification, the state in which the inertial sensor 1 or the mounting board 3 is viewed from above in the z direction, as shown in FIG. 1, for example, may be referred to as "top view".

[Basic configuration]
1, the inertial sensor 1 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 inertial sensor 1 is configured to detect an angular velocity applied to the inertial sensor 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 parts 53 (described later) of the mounting substrate 3. The inertial sensor 1 is, for example, a gyro sensor with a BRG structure, and is suitable for use in applications in which it is mounted on a vehicle such as an automobile, but can of course also be used for other applications.

1 and 2, the micro-vibrator 2 includes a curved surface portion 21 having an outer shape of a three-dimensional curved surface of a substantially hemisphere, and a recessed portion 22 recessed from the apex side of the substantially hemisphere curved surface portion 21 toward the center side of the hemisphere. The micro-vibrator 2 has a rim 211, which is an end portion of the curved surface portion 21 opposite the recessed portion 22, having a substantially cylindrical shape. For example, the curved surface portion 21 of the micro-vibrator 2 has a bowl-shaped three-dimensional curved surface, and the Q value of the vibration is 10 ⁶ or more. When the micro-vibrator 2 is mounted on the mounting substrate 3, for example, the surface 2a side of the rim 211 faces a plurality of electrode portions 53 of the mounting substrate 3 described later, and the plurality of electrode portions 53 are spaced at equal intervals.

As shown in FIG. 3, for example, the micro-vibrator 2 has a surface with a larger outer diameter as the front surface 2a and a back surface 2b as the opposite surface, and the bottom surface of the recess 22 in the Z direction on the back surface 2b side serves as the mounting surface 22b to be bonded to the mounting substrate 3. For example, the bottom surface of the recess 22 in the Z direction on the front surface 2a side serves as the adsorption surface 22a used for transport when mounting the micro-vibrator 2 on the mounting substrate 3. When mounted on the mounting substrate 3, the micro-vibrator 2 has a structure in which the curved surface portion 21 including the rim 211 is in a hollow state where it does not come into contact with other members, and the hollow rim 211 vibrates in a wine glass mode.

As shown in FIG. 3, the micro-vibrator 2 has a shape in which the surface of the rim 211 that connects the front surface 2a and the back surface 2b is the rim undersurface 211c, and the rim undersurface 211c and the mounting surface 22b form the same imaginary plane 22b1. This is the result of simultaneously forming the rim undersurface 211c and the mounting surface 22b by polishing and CMP in the formation process of the micro-vibrator 2 described later. Since the rim undersurface 211c and the mounting surface 22b of the micro-vibrator 2 are in the same plane, when the micro-vibrator 2 is mounted on the mounting substrate 3, the positional variation in the height direction of the rim 211 relative to the multiple electrode parts 53 of the mounting substrate 3 is reduced. In other words, the micro-vibrator 2 has a shape that reduces the area variation of the rim 211 that is arranged opposite the multiple electrode parts 53 when mounted on the mounting substrate 3. For example, the entire front surface 2a and back surface 2b of the micro-vibrator 2 are covered with the conductive layer 23.

The conductive layer 23 is, for example and not limited to, made of a laminated film of Cr (chromium) or Ti (titanium) and any conductive material such as Au (gold) or Pt (platinum) from the base side, and functions as an electrode film. The conductive layer 23 is formed on the front surface 2a and rear surface 2b of the micro-vibration body 2 by any vacuum film formation method such as sputtering or vapor deposition.

The micro-vibrator 2 is made of materials such as quartz, glass, silicon, and ceramic, but is not limited to these materials as long as it can form the curved surface portion 21 and the recessed portion 22 in a three-dimensional curved shape and can vibrate in wine glass mode. The micro-vibrator 2 is formed by processing a thin-walled base material made of the above-mentioned materials, for example, in a forming process described below, to form a thin-walled member on the order of micrometers, with the curved surface portion 21 and the recessed portion 22 having thicknesses of 20 μm to 80 μm. The micro-vibrator 2 has a millimeter-sized shape, for example, with the height direction being along the thickness direction of the mounting substrate 3, with a height dimension of 2.5 mm and an outer diameter of the rim 211 on the surface 2a side being 5 mm.

The micro-vibration body 2 is formed, for example, by the following process.

First, as shown in FIG. 4A, for example, a quartz plate 20, a mold M for forming a three-dimensional curved shape, and a cooling body C for cooling the mold M are prepared. The mold M includes, for example, a recess M1 that serves as a space when forming a three-dimensional curved shape on the quartz plate 20, and a columnar support M2 that extends along the depth direction of the recess M1 at the center of the recess M1 and supports a part of the quartz plate 20 during processing. The mold M has a through hole M11 formed in the bottom surface of the recess M1, and is attached to the cooling body C so that the through hole M11 communicates with the cooling body C. The cooling body C includes an insertion portion C1 into which the mold M is inserted, and an exhaust port C11 on the bottom surface of the insertion portion C1, and serves to cool the mold M when the quartz plate 20 is processed. The quartz plate 20 is arranged to cover the entire area of the recess M1 of the mold M.

Next, as shown in FIG. 4B, for example, a flame F is blown from a torch T toward the quartz plate 20 to heat and melt the quartz plate 20. At this time, the recess M1 of the mold M is evacuated through the exhaust port C11 of the cooling body C by a vacuum mechanism (not shown). As a result, the molten part of the quartz plate 20 is stretched toward the bottom surface of the recess M1, and its central peripheral area is supported by the support part M2. After that, by stopping the heating of the quartz plate 20 and cooling it, the quartz plate 20 is formed with a curved surface part 201 having a substantially hemispherical three-dimensional curved shape, and a recessed part 202 recessed near the center of the curved surface part 201 by being supported by the support part M2. In addition, the part of the quartz plate 20 located outside the recess M1 is located at the outer peripheral end of the curved surface part 201, and becomes a flat-shaped end part 203.

Then, the depression M1 of the mold M is returned to normal pressure, the processed quartz plate 20 is removed, and the quartz plate 20 is sealed with a sealant E made of any curable resin material, as shown in FIG. 4C, for example. After that, as shown in FIG. 4D, for example, the sealant E is polished and CMP (short for Chemical Mechanical Polishing) is performed from the surface close to the end 203, and the end 203 and the tip portion of the recessed portion 202 are removed together with the sealant E. As a result, the quartz plate 20 has a curved surface portion 21 with an annular curved surface and a recessed portion 22 recessed from the curved surface portion 21, and the rim lower surface 211c and the mounting surface 22b are shaped to be located on the same plane.

Then, all of the sealing material E is removed by any method, such as heating or dissolving with a chemical solution, and the quartz plate 20 is removed. Finally, a conductive layer 23 is formed on the front and back surfaces of the processed quartz plate 20 by any film formation process, such as sputtering, vapor deposition, atomic layer deposition (ALD), or chemical vapor deposition (CVD).

The micro-vibration body 2 is manufactured, for example, by the manufacturing process described above, and has a roughly half-toroidal shape that is rotationally symmetric with the Z direction as the axis of rotation, but the method for forming the base material is not limited to the above method, and other known methods may be used. Furthermore, the micro-vibration body 2 is not limited to the BR shape as long as it has a shape that allows it to vibrate in wine glass mode.

As shown in FIG. 5, the mounting substrate 3 comprises a lower substrate 4 and an upper substrate 5 which are bonded together. For example, the mounting substrate 3 is obtained by anodically bonding the upper substrate 5 made of a semiconductor material, Si (silicon), to the lower substrate 4 made of an insulating material, borosilicate glass. The mounting substrate 3 comprises an inner frame portion 51, a plurality of electrode portions 53 arranged at a distance from each other to surround the inner frame portion 51, and an outer frame portion 54 arranged to surround the electrode portions 53.

The inner frame portion 51 has, for example, a circular ring shape when viewed from above, but is not limited to this shape as long as it is a frame shape that surrounds the area of the lower substrate 4 to which the micro-vibration body 2 is bonded. As shown in Figures 8 and 9, for example, the outer and inner diameters of the inner frame portion 51 are sized so that they do not come into contact with the micro-vibration body 2, which is approximately M-shaped when viewed in cross section.

The multiple electrode portions 53 are arranged at a distance from one another around the inner frame portion 51 at positions on the outer periphery of the etching groove 41. As shown in FIG. 5, for example, when viewed from above, the multiple electrode portions 53 have inner and outer periphery sides each having an arc shape, and when the inner and outer periphery sides are connected, they form intermittent circles of different diameters. In other words, the multiple electrode portions 53 are configured such that a ring surrounding the inner frame portion 51 is evenly divided at predetermined intervals.

As shown in FIG. 6, the electrode film 531 is formed on the upper surface of each of the electrode parts 53. The electrode parts 53 are electrically connected to an external circuit board or the like (not shown) by connecting wires (not shown) to the electrode film 531, so that the potential of the electrode parts 53 can be controlled. When the micro-vibrator 2 is mounted, each of the electrode parts 53 is spaced a predetermined distance from the rim 211 of the micro-vibrator 2, as shown in FIG. 1 or FIG. 8, for example. Each of the electrode parts 53 forms a capacitor with the micro-vibrator 2. In other words, the mounting board 3 can detect the electrostatic capacitance between the micro-vibrator 2 and the mounting board 3 through the electrode parts 53, generate electrostatic attraction between the micro-vibrator 2 and vibrate the micro-vibrator 2 in wine glass mode.

The "inner circumference side" of the mounting substrate 3 means the center side of the inner region surrounded by the inner frame portion 51 in a top view as shown in FIG. 5, and the "outer circumference side" means the side located opposite the inner circumference side. Also, FIG. 1 and other figures show an example in which 16 electrode portions 53 are evenly arranged on the mounting substrate 3 so as to form a ring at a distance from each other, but this is not limited to this, and the number and arrangement of the electrode portions 53 can be changed as appropriate depending on the shape and size of the micro-vibration body 2, etc.

When viewed from above, the outer frame portion 54 is in the shape of a single frame surrounding the inner frame portion 51, and has an electrode film 541 made of Al or the like on its upper surface, as shown in, for example, Figures 5 and 7. The outer frame portion 54 has wires (not shown) connected to the electrode film 541, and is electrically connected to an external circuit board (not shown), etc., so that the potential of the outer frame portion 54 can be controlled by an external power source (not shown).

When viewed from above, the mounting substrate 3 has an annular etching groove 41 formed at a position on the outer periphery side of the annular inner frame portion 51, surrounding the inner frame portion 51. As a result, when the micro-vibrator 2 is mounted on the mounting substrate 3, the curved surface portion 21 including the rim 211 of the micro-vibrator 2 becomes hollow, as shown in, for example, Figures 8 and 9.

5, the mounting substrate 3 has a bridge wiring 42 that connects the inner frame portion 51 and the outer frame portion 54 while straddling the etching groove 41 of the lower substrate 4 in a top view. The bridge wiring 42 is made of a conductive material such as Al (aluminum) and is arranged to pass between the multiple electrode portions 53 and is electrically independent from the multiple electrode portions 53. As shown in FIG. 7, one end of the bridge wiring 42 is covered by the outer frame portion 54 and the other end on the opposite side is covered by the inner frame portion 51. As a result, the bridge wiring 42 electrically connects the inner frame portion 51 and the outer frame portion 54 and plays a role of making them at the same potential. In addition, a bonding member 52 is arranged in the inner area surrounded by the inner frame portion 51 of the mounting substrate 3, and the micro-vibrator 2 is bonded thereto, so that the outer frame portion 54 is electrically connected to the micro-vibrator 2 via the bridge wiring 42, the inner frame portion 51, and the bonding member 52. In other words, the mounting substrate 3 is capable of adjusting the potential of the micro-vibrator 2 by adjusting the potential of the outer frame portion 54. Note that the number and arrangement of the bridge wiring 42 are not limited to the example shown in FIG. 5 and can be changed as appropriate.

The mounting substrate 3 can be manufactured, for example, by the following process.

First, a lower substrate 4 made of, for example, borosilicate glass is prepared, and an annular etching groove 41 is formed by wet etching using buffered hydrofluoric acid. Then, a bridge wiring 42 spanning the etching groove 41 is formed by a lift-off method using, for example, Al sputtering to form a film. The thickness of the bridge wiring 42 is, for example, about 0.1 μm.

Next, a Si substrate (later upper substrate 5) made of, for example, Si is prepared and anodically bonded to the lower substrate 4 made of borosilicate glass. Next, grooves that partition the areas that will later become the inner frame portion 51, the multiple electrode portions 53, and the outer frame portion 54 are formed in the Si substrate by a known etching method.

Specifically, for example, trench etching is performed by DRIE (short for Deep Reactive Ion Etching) to expose the lower substrate 4 and separate the inner frame portion 51, the multiple electrode portions 53, and the outer frame portion 54. As a result, the Si substrate becomes the upper substrate 5 having the inner frame portion 51, the multiple electrode portions 53, and the outer frame portion 54 that are spaced apart from one another. In addition, the etching grooves 41 formed in the lower substrate 4 are exposed from the upper substrate 5 by this partitioning process of the Si substrate.

Finally, electrode films 531, 541 are formed on the upper surfaces of the multiple electrode portions 53 and the outer frame portion 54 by sputtering or the like. As a result of this process, the mounting substrate 3 having the above-mentioned structure is obtained. Then, when the micro-vibrator 2 is mounted on the mounting substrate 3, the bonding member 52 is placed in the positioning groove 43 of the lower substrate 4. The bonding member 52 is, for example, a paste-like conductive material made of a conductive material such as AuSn (gold tin), Ag (silver), or Au, and is applied to the inner region surrounded by the inner frame portion 51.

Note that one mounting substrate 3 shown in FIG. 5 etc. can be obtained, for example, by forming areas on a wafer that will become multiple mounting substrates 3 of the above structure, and then dividing the wafer into individual pieces by dicing or the like. In other words, the manufacturing of the mounting substrate 3 can be handled at the wafer level.

In addition, the mounting substrate 3 is attached to the micro-vibrator 2 so that a cap member (not shown) does not come into contact with the micro-vibrator 2 in a vacuum environment with a vacuum level equal to or lower than a predetermined level, and the micro-vibrator 2 is vacuum-tightly sealed.

The above is the basic configuration of the inertial sensor 1. When the inertial sensor 1 is driven, it generates an electrostatic attraction between some of the multiple electrode parts 53 and the micro-vibrator 2, causing the micro-vibrator 2 to vibrate in wine glass mode. When an external Coriolis force is applied to the inertial sensor 1 while the micro-vibrator 2 is in a vibrating state, the micro-vibrator 2 is displaced and the position of the node of the vibration mode changes. The inertial sensor 1 detects the change in the node of this vibration mode by the electrostatic capacitance between the micro-vibrator 2 and the multiple electrode parts 53, making it possible to detect the angular velocity acting on the inertial sensor 1.

This inertial sensor 1 has a micro-vibrator 2 shaped so that the mounting surface 22b and the rim underside 211c are located on the same plane, and is joined to a mounting substrate 3, thereby reducing the variation in capacitance of each capacitor formed by the rim 211 and the multiple electrode portions 53.

Here, the above effects due to the shape of the micro-vibration body 2 will be explained by comparing it with the micro-vibration body 6 of the comparative example shown in FIG. 10A.

The micro-vibration body 6 of the comparative example has a curved surface portion 61 of a substantially hemispherical shape, a recessed portion 62 recessed from the apex of the substantially hemispherical curved surface portion 61 toward its center, and an electrode film 63 covering these, and has a shape in which the rim lower surface 611c of the rim 611 protrudes downward in the z direction beyond the bottom surface 62b of the recessed portion 62. The micro-vibration body 6 of the comparative example is formed, for example, in the same manner as the micro-vibration body 2 of this embodiment, by going through the steps shown in Figures 4A to 4C, and then stopping the process of removing unnecessary parts at a stage before the bottom surface 62b of the recessed portion 62 is reached. Therefore, the micro-vibration body 6 of the comparative example has a shape in which the rim lower surface 611c is located on the same plane as the bottom surface 62b of the recessed portion 62, as shown by the dashed line, and is located on a different plane from the bottom surface 62b of the recessed portion 62.

When the grinding surface is tilted relative to the bottom surface 62b of the recess 62 in the above-mentioned process of removing unnecessary portions, the degree to which the rim 611 protrudes relative to the bottom surface 62b differs on the left and right sides in cross-sectional view, as in the micro-vibration body 6 of the comparative example. When the micro-vibration body 6 of the comparative example is mounted on the mounting substrate 3 and an inertial sensor is obtained in a state in which the micro-vibration body 6 of the comparative example is tilted relative to the mounting substrate 3, this is referred to as the "inertial sensor 100 of the comparative example."

Specifically, in the inertial sensor 100 of the comparative example, as shown in FIG. 10B, the micro-vibrator 6 of the comparative example is tilted, and the area of the rim 611 arranged opposite each of the multiple electrode parts 53 of the mounting substrate 3 is greatly different. For example, in the micro-vibrator 6 of the comparative example, a distribution occurs in the height position of the rim lower surface 611c in the z direction, and there are parts where the rim 611 faces only a part of the side surface of the electrode part 53 along the z direction, and parts where it faces the entire side surface of the electrode part 53. In this case, the electrode part 53 whose entire side surface faces the rim 611 and the electrode film 63 covering it has a larger capacitance than the other electrode part 53 whose only a part of the side surface faces the rim 611 and the electrode film 63 covering it. In other words, the inertial sensor 100 of the comparative example has a configuration in which the capacitance varies greatly for each of the multiple electrode parts 53, and the sensor accuracy decreases.

In contrast, the inertial sensor 1 of this embodiment is configured using a micro-vibrator 2 in which the mounting surface 22b and the rim underside 211c are located on the same plane, so even if the micro-vibrator 2 is tilted, the area variation of the rim 211 arranged opposite the electrode portion 53 is reduced. As a result, the inertial sensor 1 has reduced capacitance variation of each capacitor configured by the rim 211 and multiple electrode portions 53 compared to the inertial sensor 100 of the comparative example, and an effect of improving sensor accuracy is obtained.

Note that FIG. 10A is a cross-sectional view showing a cross section corresponding to FIG. 3. FIG. 10B is a cross-sectional view showing a cross section corresponding to FIG. 9.

[Inertial sensor manufacturing method]
Next, the manufacturing method of the inertial sensor 1 of this embodiment will be described with reference to Figures 11A to 11E. However, since the manufacture of the micro-vibrator 2 and the mounting substrate 3 themselves has been described above, the process of joining the micro-vibrator 2 to the mounting substrate 3 will be mainly described here.

Note that Figures 11A to 11E correspond to the cross-sectional view shown in Figure 9. Also, in Figures 11C to 11E, for ease of viewing, only a portion of the pick-up mechanism 300 (described later) is shown in a simplified manner, and the inside of the collet 302 is shown with a dashed line. Also, in Figures 11D and 11E, for ease of understanding, the movement direction of the pick-up mechanism 300 is shown with a hollow arrow.

First, as shown in FIG. 11A, for example, a micro-vibrator 2 and a mounting substrate 3 manufactured by the above-mentioned method are prepared. Then, for example, as shown in FIG. 11B, a bonding member 52 is placed in the inner area surrounded by an inner frame portion 51. For example, a conductive bonding material such as Au paste or Ag paste is used as the bonding member 52, and the bonding member 52 is placed by applying it using a syringe or the like.

Then, for example, the mounting substrate 3 is placed on the suction surface of a mounter device (not shown), and the mounting substrate 3 is fixed by vacuum suction. Note that this mounter device (not shown) is configured with a heating mechanism capable of heating the suction surface.

Next, as shown in FIG. 11C, for example, a part of the pickup mechanism 300 is inserted into the suction surface 22a, which is the bottom of the recess 22 of the micro-vibrator 2 on the surface 2a side, and the micro-vibrator 2 is gripped by vacuum suction. The pickup mechanism 300 includes, for example, a base 301 and a collet 302 having a substantially cylindrical shape, and the base 301 is connected to a transport unit and a vacuum mechanism (not shown), and is configured to be capable of vacuum suction by the collet 302 and transport of the object that has been sucked up. For example, the maximum diameter of the collet 302 is smaller than the inner diameter of the recess 22, and the outer diameter of the tip of the collet 302 is smaller than the other parts. In addition, the pickup mechanism 300 is configured such that the length of the collet 302 is greater than the depth of the recess 22 of the micro-vibrator 2, and when the collet 302 is inserted into the recess 22 of the micro-vibrator 2, the collet 302 does not come into contact with anything other than the suction surface 22a of the micro-vibrator 2. This prevents the conductive layer 23 and base material of the micro-vibration body 2 from being damaged when the micro-vibration body 2 is transported.

Meanwhile, the mounting substrate 3 is heated while being adsorbed by a mounter device (not shown) to melt or soften the bonding member 52. Then, for example as shown in FIG. 11D, the above-mentioned pickup mechanism 300 is used to hold the adsorption surface 22a of the micro-vibrator 2 by vacuum adsorption while the mounting surface 22b of the recess 22 of the micro-vibrator 2 is inserted inside the inner frame portion 51 of the mounting substrate 3. Then, the micro-vibrator 2 is brought closer to the mounting substrate 3, and the mounting surface 22b of the micro-vibrator 2 is brought into contact with the bonding member 52.

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 mounting substrate 3 and extracting feature points by edge detection using known image processing techniques, thereby adjusting the relative positions.

Then, the temperature of the suction surface of a mounting device (not shown) is lowered, and the molten bonding material 52 is solidified to bond the micro-vibrator 2 and the mounting substrate 3. Then, as shown in FIG. 11E, for example, the inside of the collet 302 is returned to normal pressure to release the vacuum suction of the micro-vibrator 2, the pickup mechanism 300 is retracted, and the collet 302 is removed from the recess 22 of the micro-vibrator 2.

Next, the suction by the mounting device (not shown) or the like is released, and the mounting substrate 3 to which the micro-vibrator 2 is bonded is removed from the suction surface. The mounting substrate 3 is then mounted on a circuit substrate (not shown) or the like, and wire bonding is performed on the electrode films 531, 541 of the mounting substrate 3 to electrically connect the circuit substrate or the like to the electrode portion 53 and outer frame portion 54 of the mounting substrate 3. Finally, for example, a cap material (not shown) is attached in a vacuum environment to the mounting substrate 3 or an external member to which the mounting substrate 3 is attached, and the micro-vibrator 2 is hermetically sealed in the internal space formed by the mounting substrate 3 and the cap material (not shown). Through these steps, the inertial sensor 1 according to the embodiment can be manufactured.

The above is the basic manufacturing method of the inertial sensor 1 of this embodiment. Note that, although the method of gripping the micro-vibrator 2 has been described here as a representative example in which the suction surface 22a of the recess 22 is vacuum-sucked, the method is not limited to this. For example, the configuration of the collet 302 may be changed to grip the side wall on the surface 2a side of the recess 22 by vacuum suction, or the side wall may be mechanically pressed at two or more points to grip the micro-vibrator 2.

According to this embodiment, the micro-vibrator 2 has a curved surface portion 21 that can vibrate in wine glass mode, a recessed portion 22, and the mounting surface 22b of the recessed portion 22 on the back surface 2b side and the rim lower surface 611c of the rim 611 are located on the same plane, and is joined to the mounting substrate 3 to form an inertial sensor 1. By having the mounting surface 22b and the rim lower surface 611c located on the same plane, even if the micro-vibrator 2 is tilted with respect to the mounting substrate 3, the area variation of the rim 211 arranged opposite the multiple electrode portions 53 is reduced. Therefore, this inertial sensor 1 has the effect of suppressing the variation in the electrostatic capacitance of each capacitor formed by the rim 211 and the multiple electrode portions 53, and improving the sensor accuracy.

(Modification of the first embodiment)
In the above first embodiment, an example was described in which a micro-vibrator 2 having a shape in which the suction surface 22a and the mounting surface 22b are parallel and the mounting surface 22b and the rim underside 211c are located on the same plane was used, but this is not limited to this.

As shown in FIG. 12, the mounting surface 22b and the rim lower surface 211c of the micro-vibrator 2 may be located on the same plane, while the mounting surface 22b may not be parallel to the suction surface 22a. In this case, as shown in FIG. 13, when the mounting surface 22b of the micro-vibrator 2 is arranged parallel to the mounting surface of the mounting board 3, the height position in the z direction of the rim lower surface 211c is the same in the left-right direction of the paper surface of FIG. 13. In other words, in the inertial sensor 1, the areas of the rims 211 arranged opposite the multiple electrode parts 53 are all the same. Even if the micro-vibrator 2 is tilted with respect to the mounting board 3, the mounting surface 22b and the rim lower surface 211c are located on the same plane, so that the inertial sensor 1 has reduced variation in the area of the rims 211 arranged opposite the multiple electrode parts 53.

This modification also provides the same effects as the first embodiment.

Second Embodiment
The inertial sensor 1 of the second embodiment will be described with reference to Fig. 14 and Fig. 15. Fig. 14 is a cross-sectional view showing a cross section corresponding to Fig. 9. Fig. 15 is a cross-sectional view showing a cross section corresponding to Fig. 3.

The inertial sensor 1 of this embodiment differs from the first embodiment in that, as shown in FIG. 14, the micro-vibrator 2 has a side through-hole 24, which is a through-hole formed on the side surface of the recess 22 near the adsorption surface 22a, and the bonding member 52 flows into the side through-hole 24. This difference will be mainly described in this embodiment.

In this embodiment, the micro-vibrator 2 has a side through hole 24 connecting the front surface 2a and the back surface 2b of the substrate on the side surface of the recess 22 near the bottom surface of the front surface 2a, i.e., on the side wall portion near the adsorption surface 22a, as shown in FIG. 15, for example. The side through hole 24 is formed, for example, by irradiating a thin-walled substrate (such as quartz) constituting the micro-vibrator 2 with laser light to partially melt it. The side through hole 24 can also be formed, for example, by pre-opening a through hole in an area of the quartz plate 20 located slightly outside the support portion M2 of the mold M in the process shown in FIG. 4A. The side through hole 24 is formed in a position lower than the height of the inner frame portion 51 in the z direction of the recess 22 when the micro-vibrator 2 is mounted on the mounting substrate 3, as shown in FIG. 14, for example. The side through hole 24 is formed, for example, in two positions symmetrically in a top view, but is not limited to this, and the number and positions can be changed as appropriate.

In this embodiment, a portion of the bonding member 52 flows into the side through-hole 24 of the micro-vibrator 2 and can cover the bottom surface of the recess 22 of the micro-vibrator 2 on the surface 2a side, i.e., the adsorption surface 22a, in part or all. In other words, even if the amount of bonding member 52 is large, a portion of the bonding member 52 flows into the side through-hole 24 of the micro-vibrator 2, and the presence of an excessive amount of bonding member 52 between the mounting surface 22b and the mounting surface of the mounting board 3 is suppressed. In this case, the contact area between the micro-vibrator 2 and the bonding member 52 is increased compared to the first embodiment, thereby improving the bonding strength of the micro-vibrator 2.

According to this embodiment, the inertial sensor 1 can obtain the same effect as the first embodiment. In addition, since the side through hole 24 is formed in the micro-vibrator 2, even if the amount of the bonding member 52 arranged on the mounting substrate 3 is increased, a part of the bonding member 52 flows into the side through hole 24. Therefore, it is possible to prevent the bonding member 52 from being interposed more than necessary between the mounting surface 22b and the mounting surface of the mounting substrate 3, and thus to prevent the micro-vibrator 2 from tilting with respect to the mounting substrate 3. In addition, when the bonding member 52 reaches the suction surface 22a, the contact area between the micro-vibrator 2 and the bonding member 52 increases, and the effect of improving the bonding strength is also obtained.

Third Embodiment
The inertial sensor 1 of the third embodiment will be described with reference to Fig. 16 to Fig. 18. Fig. 16 is a cross-sectional view showing a cross section corresponding to Fig. 9. Fig. 17 is a cross-sectional view showing a cross section corresponding to Fig. 3.

The inertial sensor 1 of this embodiment differs from the first embodiment in that, as shown in FIG. 16, the micro-vibrator 2 has a bottom through-hole 25 on the bottom surface of the recess 22 in the z-direction, and the bonding material 52 flows into the bottom through-hole 25. This difference will be mainly described in this embodiment.

In this embodiment, the micro-vibration body 2 has a bottom through-hole 25 that is connected to the mounting surface 22b on the bottom surface of the recess 22 in the z direction, as shown in FIG. 17. The bottom through-hole 25 is formed, for example, by the same method as the side through-hole 24 of the second embodiment. The bottom through-hole 25 may be formed, for example, as shown in FIG. 18, by preparing a molding mold M having a protrusion M21 at the upper end of the support part M2, and polishing and removing all of the protruding parts of the recess 202 that follow the protrusion M21. The bottom through-hole 25 is formed, for example, at the center position of the mounting surface 22b, but is not limited to this, and may be formed in multiple places, or may be formed at a position different from the center position of the mounting surface 22b, and the number and positions of the holes may be changed as appropriate.

In this embodiment, the bonding member 52 can flow into the bottom through-hole 25 of the micro-vibrator 2 and cover part or all of the suction surface 22a of the recess 22 of the micro-vibrator 2. As a result, as in the second embodiment, the presence of an excessive amount of bonding member 52 between the mounting surface 22b and the mounting surface of the mounting substrate 3 is suppressed, and the contact area between the micro-vibrator 2 and the bonding member 52 is increased, resulting in an effect of improving the bonding strength of the micro-vibrator 2. In addition, since the bottom through-hole 25 is located on the mounting surface 22b, even if air bubbles are present in the bonding member 52, the air bubbles can easily escape to the outside through the bottom through-hole 25, and the effect of more stable bonding between the micro-vibrator 2 and the mounting substrate 3 is obtained.

According to this embodiment, the inertial sensor 1 can obtain the same effect as the first embodiment. In addition, since the micro-vibrator 2 has a bottom through-hole 25 and a part of the bonding member 52 flows into the bottom through-hole 25, it is possible to suppress the tilt of the micro-vibrator 2, reduce the influence of air bubbles in the bonding member 52, and improve the bonding strength between the micro-vibrator 2 and the mounting substrate 3.

(Modification of the third embodiment)
The inertial sensor 1 of the third embodiment may have a configuration in which a support portion 55 that is a part of the mounting substrate 3 is inserted into a bottom through-hole 25 of the micro-vibrator 2, as shown in, for example, FIG.

Specifically, when the micro-vibrator 2 has a bottom through-hole 25, the mounting substrate 3 may further include a support 55 arranged in an inner region surrounded by the inner frame 51 when viewed from above, as shown in FIG. 20, for example. The support 55 has a diameter smaller than the inner diameter of the bottom through-hole 25 and can be inserted into the bottom through-hole 25. The support 55 is formed, for example, by etching simultaneously with the inner frame 51, the electrode 53, and the outer frame 54. As shown in FIG. 21, for example, the inertial sensor 1 according to the modified example is joined to the mounting substrate 3 by the joining member 52 with the micro-vibrator 2 and the support 55 inserted into the bottom through-hole 25. When a plurality of bottom through-holes 25 are provided, the mounting substrate 3 may be configured to have the same number of support 55 as the bottom through-holes 25.

This modified example also provides the same effect as the third embodiment. In addition, because the support column 55 is fitted into the bottom through-hole 25 when bonding the micro-vibrator 2 to the mounting substrate 3, it also provides the effect of facilitating alignment with the mounting substrate 3.

Fourth Embodiment
The inertial sensor 1 of the fourth embodiment will be described with reference to Fig. 22 to Fig. 24. Fig. 22 is a cross-sectional view showing a cross section corresponding to Fig. 9. Fig. 23 is a cross-sectional view showing a cross section corresponding to Fig. 3.

The inertial sensor 1 of this embodiment differs from the first embodiment in that, as shown in FIG. 22, the micro-vibrator 2 has a mounting surface recess 26 on the mounting surface 22b side of the recess 22 that is recessed toward the surface 2a, and the mounting substrate 3 has a positioning groove 43. This difference will be mainly described in this embodiment.

In this embodiment, as shown in FIG. 23, the micro-vibration body 2 has a mounting surface recess 26 recessed toward the front surface 2a at the bottom of the recess 22 on the mounting surface 22b side. The micro-vibration body 2 has a protruding portion 27 protruding from the bottom surface of the mounting surface recess 26, and the tip surface of the protruding portion 27 forms the mounting surface 22b located on the same plane as the rim lower surface 211c.

In this embodiment, as shown in FIG. 24, for example, the mounting substrate 3 is an inner region of the lower substrate 4 surrounded by an inner frame portion 51, and has an annular positioning groove 43 formed at a position corresponding to the protrusion 27 of the micro-vibrator 2. The positioning groove 43 is formed, for example, in an etching process such as DRIE at the same time as the etching groove 41. As shown in FIG. 22, for example, the positioning groove 43 has a width that allows the protrusion 27 of the micro-vibrator 2 to enter, and serves to facilitate the positioning of the micro-vibrator 2 relative to the mounting substrate 3.

The micro-vibration body 2 of this embodiment is formed, for example, through the process shown in Figures 25A and 25B. First, as shown in Figure 25A, a mold M for forming a three-dimensional curved surface is prepared, which has a recessed portion M22 on the tip surface of the support portion M2. Next, the quartz plate 20 is melted by a flame F to form the curved surface portion 201 and the recessed portion 202. At this time, the recessed portion 202 follows the recessed portion M22 as shown in Figure 25B, and later takes on a shape corresponding to the mounting surface recess 26 and the protruding portion 27.

Although an example of manufacturing the micro-vibration body 2 using a mold M having a recessed portion M22 as the support portion M2 has been described, the present invention is not limited to this. For example, instead of the recessed portion M22, a mold having a through hole that communicates with the bottom side of the fitting portion C1 of the cooling body C may be used, and the mounting surface recess 26 may be formed by vacuum drawing, and the method of forming the mounting surface recess 26 may be changed as appropriate.

According to this embodiment, the inertial sensor 1 can obtain the same effect as the first embodiment. In addition, this inertial sensor 1 has a micro-vibrator 2 having a mounting surface recess 26, and the protrusion 27 of the micro-vibrator 2 is inserted into the positioning groove 43 of the mounting substrate 3, so that the effect of facilitating positioning of the micro-vibrator 2 is also obtained.

(Modification of the fourth embodiment)
The inertial sensor 1 of the fourth embodiment may be configured such that, for example, as shown in Fig. 26, the micro-vibrator 2 further has a bottom surface through-hole 25 in the mounting surface recess 26, and the mounting substrate 3 further has a support portion 55 as shown in Fig. 27, and these are joined together. In this inertial sensor 1, for example, as shown in Fig. 28, the support portion 55 of the mounting substrate 3 is inserted into the bottom surface through-hole 25 of the micro-vibrator 2.

In addition to the effects of the fourth embodiment, this modification provides the effects of improving the positioning accuracy of the micro-vibration body 2 by inserting the support portion 55 into the bottom through-hole 25, and reducing the effect of air bubbles in the joining member 52.

The inertial sensor 1 according to this modified example may have a configuration in which the recess 22 is filled with a bonding member 52, as shown in FIG. 29, for example. Since the recess 22 of this inertial sensor 1 is filled with the bonding member 52, it is possible to connect a wire (not shown) to the bonding member 52 on the upper side in the z direction. For example, this inertial sensor 1 can directly connect one of the multiple electrode films 541 on the upper surface of the outer frame portion 54 to the bonding member 52 filling the recess 22 with a wire. In this case, the mounting substrate 3 does not require the bridge wiring 42.

The inertial sensor 1 in FIG. 29 can be manufactured, for example, as shown in FIG. 30, by attaching a micro-vibrator 2 having a bottom through-hole 25 and a mounting surface recess 26 to a mounting substrate 3 having a positioning groove 43 and a support portion 55, and then pouring a bonding member 52 into the recess 22 and solidifying it. Even with this configuration, the same effect as the above-mentioned modified example can be obtained. In addition, since the bonding area between the bonding member 52 and the micro-vibrator 2 is increased, the effect of further improving the bonding strength between the micro-vibrator 2 and the mounting substrate 3 can be obtained. Furthermore, since the bonding member 52 is poured into the recess 22 and bonded after the micro-vibrator 2 is attached to the mounting substrate 3, the micro-vibrator 2 is not placed on the bonding member 52 in a fluid state, and therefore no tilt due to the bonding member 52 occurs.

Other Embodiments
Although the present invention has been described based on the embodiment, it is understood that the present invention is not limited to the embodiment or structure. The present invention also includes various modifications and modifications within the equivalent range. In addition, various combinations and forms, and other combinations and forms including only one element, more than one, or less than one, are also within the scope and concept of the present invention.

(1) For example, FIG. 29 shows an example of an inertial sensor 1 in which the mounting substrate 3 has both a positioning groove 43 and a support portion 55, but the micro-vibrator 2 may not have a mounting surface recess 26 and the mounting substrate 3 may not have a positioning groove 43.

(2) The inertial sensor 1 according to the fourth embodiment and its modified example may be configured such that the protrusion 27 of the micro-vibrator 2 is curved and bowl-shaped in cross section over the entire area, with no flat portion, as shown in FIG. 31, for example. In this case, the micro-vibrator 2 has a structure in which the apex of the protrusion 27 is the tip 28, for example, the tip 28 is annular and located on the same plane as the rim lower surface 211c. In other words, when the micro-vibrator 2 is mounted on the mounting substrate 3, the mounting surface 22b of the protrusion 27 does not contact the mounting substrate 3 in a plane, but the tip 28 contacts the mounting substrate 3 at a point.

This micro-vibration body 2 can be manufactured in a manner basically similar to that of the fourth embodiment, except that the process of removing the end 203 where the rim lower surface 211c is formed is stopped when the apex of the protrusion 27 is reached. For example, in the process of removing the end 203, the micro-vibration body 2 is ground to the distance between the surface of the mold M in contact with the quartz plate 20 shown in FIG. 25 and the tip surface of the support part M2, resulting in the above structure.

2... Micro vibrator, 2a... Front surface, 2b... Back surface, 20... Thin base material,
201: curved surface portion, 202: concave portion, 21: curved surface portion, 211: rim,
211c: rim lower surface, 22: recess, 22b: mounting surface,
24: through hole, 25: (bottom surface) through hole, 26: mounting surface recess,
27: protrusion; 3: mounting substrate; 4: lower substrate; 43: positioning groove;
5: upper substrate, 51: inner frame portion, 52: bonding member, 53: electrode portion,
55: Support portion, E: Sealing material

Claims (7)

An inertial sensor,
A micro-vibration body (2) is a thin-walled member having a front surface (2a) which is a surface on the side with a larger outer diameter and a back surface (2b) which is the opposite surface to the front surface, the micro-vibration body having a curved surface portion (21) having an annular curved surface and a bottomed cylindrical recessed portion (22) recessed from the curved surface portion toward the back surface;
a mounting substrate (3) formed by joining an upper substrate (5) having a frame-shaped inner frame portion (51) and a plurality of electrode portions (53) arranged to surround the inner frame portion while being spaced apart from each other, to a lower substrate (4);
a bonding member (52) arranged in an inner region of the mounting board surrounded by the inner frame portion,
The micro-vibrator has a mounting surface (22b) that is a bottom surface of the recess on the back surface side and is disposed in the inner region and bonded to the mounting substrate via the bonding member,
A rim (211) which is a part of the curved surface including the end portion opposite to the recess is hollow,
A rim lower surface (211c) of the rim, which is a surface connecting the front surface and the back surface, is located on the same plane as the mounting surface or a tip portion (28) thereof ,
The micro-vibrator has, on the mounting surface, a mounting surface recess (26) recessed from the back surface toward the front surface, and a protrusion (27) protruding from the mounting surface recess toward the mounting surface,
The mounting substrate has a positioning groove (43) corresponding to the protrusion,
The protrusion is inserted into the positioning groove . An inertial sensor,
A micro-vibration body (2) is a thin-walled member having a front surface (2a) which is a surface on the side with a larger outer diameter and a back surface (2b) which is the opposite surface to the front surface, the micro-vibration body having a curved surface portion (21) having an annular curved surface and a bottomed cylindrical recessed portion (22) recessed from the curved surface portion toward the back surface;
a mounting substrate (3) formed by joining an upper substrate (5) having a frame-shaped inner frame portion (51) and a plurality of electrode portions (53) arranged to surround the inner frame portion while being spaced apart from each other, to a lower substrate (4);
a bonding member (52) arranged in an inner region of the mounting board surrounded by the inner frame portion,
The micro-vibrator has a mounting surface (22b) that is a bottom surface of the recess on the back surface side and is disposed in the inner region and bonded to the mounting substrate via the bonding member,
A rim (211) which is a part of the curved surface including the end portion opposite to the recess is hollow,
A rim lower surface (211c) of the rim, which is a surface connecting the front surface and the back surface, is located on the same plane as the mounting surface or a tip portion (28) thereof,
The micro-vibrator has a side through hole (24) provided on a side surface of the recess in the vicinity of a bottom surface of the front surface and connecting the front surface and the back surface,
An inertial sensor, wherein at least a portion of the joining member is inserted into the side through hole . An inertial sensor,
A micro-vibration body (2) is a thin-walled member having a front surface (2a) which is a surface on the side with a larger outer diameter and a back surface (2b) which is the opposite surface to the front surface, the micro-vibration body having a curved surface portion (21) having an annular curved surface and a bottomed cylindrical recessed portion (22) recessed from the curved surface portion toward the back surface;
a mounting substrate (3) formed by joining an upper substrate (5) having a frame-shaped inner frame portion (51) and a plurality of electrode portions (53) arranged to surround the inner frame portion while being spaced apart from each other, to a lower substrate (4);
a bonding member (52) arranged in an inner region of the mounting board surrounded by the inner frame portion,
The micro-vibrator has a mounting surface (22b) that is a bottom surface of the recess on the back surface side and is disposed in the inner region and bonded to the mounting substrate via the bonding member,
A rim (211) which is a part of the curved surface including the end portion opposite to the recess is hollow,
A rim lower surface (211c) of the rim, which is a surface connecting the front surface and the back surface, is located on the same plane as the mounting surface or a tip portion (28) thereof,
The micro-vibrator has a bottom surface through-hole (25) provided on the mounting surface,
An inertial sensor, wherein at least a portion of the joining member is inserted into the bottom surface through-hole. The micro-vibrator has a bottom surface through-hole (25) provided in a bottom surface of the mounting surface recess,
The inertial sensor according to claim 1 , wherein at least a portion of the joining member is inserted into the bottom surface through-hole. 5. The inertial sensor according to claim 3 , wherein the mounting board has, in a region surrounded by the inner frame, a support column (55) to be inserted into the bottom through-hole. A micro-vibration body (2) is a thin-walled member having a front surface (2a) which is a surface on the side with a larger outer diameter and a back surface (2b) which is the opposite surface to the front surface, the micro-vibration body having a curved surface portion (21) having an annular curved surface and a bottomed cylindrical recessed portion (22) recessed from the curved surface portion toward the back surface;
A method for manufacturing an inertial sensor in which an upper substrate (5) having a frame-shaped inner frame portion (51) and a plurality of electrode portions (53) arranged to surround the inner frame portion while being spaced apart from each other is joined to a lower substrate (4) to form a mounting substrate (3), the upper substrate (5) being joined to a lower substrate (4) via a joining member (52),
preparing the micro-vibrator;
disposing the bonding member in an inner region of the mounting substrate that is surrounded by the inner frame portion;
After arranging the bonding member, the recess of the micro-vibrator is arranged in the inner region, and a mounting surface (22b) which is a bottom surface of the recess on the back surface side is brought into contact with the bonding member;
The bonding material is melted and then solidified to bond the micro-vibrator and the mounting substrate, and a rim (211) of the curved surface of the micro-vibrator, which is an end portion of the curved surface of the micro-vibrator opposite to the recess, is made hollow.
In preparing the micro-vibrator,
A thin substrate (20) of the order of micrometers is heated, melted, and solidified to form a curved surface portion (201) that will later become the curved surface portion, and a recessed portion (202) that will later become the recessed portion, and then the thin substrate is sealed with a sealant (E);
The curved surface portion, the recessed portion, and a portion of the sealing material are removed by polishing to form the mounting surface and a rim lower surface (211c) that connects the front surface and the back surface of the rim, which are located on the same plane ;
A through hole (24, 25) is formed on the mounting surface or a side surface in the vicinity of the mounting surface,
A method for manufacturing an inertial sensor , comprising the steps of: making the rim hollow by pouring a molten portion of the joining material into the through hole . a micro-vibration body (2) which is a thin-walled member having a front surface (2a) which is a surface on the side with a larger outer diameter and a back surface (2b) which is the opposite surface to the front surface, the micro-vibration body (2) having a curved surface portion (21) with an annular curved surface, a bottomed cylindrical recess (22) recessed from the curved surface portion toward the back surface, and a through hole (25) formed in a mounting surface (22b) which is the bottom surface of the recess;
A method for manufacturing an inertial sensor in which an upper substrate (5) having a frame-shaped inner frame portion (51), a plurality of electrode portions (53) arranged to surround the inner frame portion while being spaced apart from one another, and support portions (55) arranged in an area surrounded by the inner frame portion is joined to a lower substrate (4) to form a mounting substrate (3), the upper substrate (5) being joined to a lower substrate (4) via a joining member (52),
preparing the micro-vibrator;
inserting the support portion of the mounting substrate into the through hole of the micro-vibrator and placing the micro-vibrator on the mounting substrate;
and after placing the micro-vibrator on the mounting substrate, pouring the bonding material into the recess and solidifying it to bond the micro-vibrator to the mounting substrate, and making a rim (211) of the curved portion of the micro-vibrator, which is an end portion opposite to the recess, into a hollow state.
In preparing the micro-vibrator,
A thin substrate (20) of the order of micrometers is heated, melted, and solidified to form a curved surface portion (201) that will later become the curved surface portion, and a recessed portion (202) that will later become the recessed portion, and then the thin substrate is sealed with a sealant (E);
A method for manufacturing an inertial sensor, comprising removing the curved portion, the recessed portion, and a portion of the sealing material by polishing to form the mounting surface and a rim underside (211c) that connects the front surface and the back surface of the rim, which are located on the same plane.

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