Inertial sensor

Abstract

To provide an inertial sensor ensuring bonding strength between a minute vibration body and a mounting substrate and a symmetric property of vibration of the minute vibration body during operation.SOLUTION: An inertial sensor 1 is formed by bonding a minute vibration body 2 having a curved surface part 21 and a bottomed cylindrical connection part 22 extended from the curved part 21 to a mounting substrate 3 with a connection member 52. An annular member 6 is attached to the minute vibration body 2. The mounting substrate 3 has an inner frame part 51 having a frame shape, and is formed by bonding the connection unit 22 and the inner frame part 51 with the connection member 52. The annular member 6 has a frame shape having a side surface 22c adjacent to a mounting surface 22b facing the mounting substrate 3, of the connection part 22, and is attached to the side surface 22c. The annular member 6 covers an entire area located between the inner frame part 51 and the connection part 22, of the mounting substrate 3. The connection member 52 covers an entire area of an inner wall surface 51b of the inner frame part 51, and abuts on the annular member 6.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an inertial sensor using a micro-vibrator having a three-dimensional curved surface.

Background Art

[0002] In recent years, the development of vehicle automatic driving systems has been progressing. In this type of system, a high-precision self-position estimation technology is required. For example, for so-called Level 3 automatic driving, the development of a self-position estimation system equipped with GNSS and IMU is underway. GNSS is an abbreviation for Global Navigation Satellite System. IMU is an abbreviation for Inertial Measurement Unit, and is, for example, a six-axis inertial force sensor composed of a three-axis gyro sensor and a three-axis acceleration sensor. In the future, in order to realize so-called Level 4 or higher automatic driving, an IMU with higher sensitivity than the current level is required.

[0003] As a gyro sensor for realizing such a high-sensitivity IMU, BRG is regarded as promising, and a micro-vibrator having a substantially hemispherical three-dimensional curved surface vibrating in a wine glass mode is mounted on a mounting substrate. BRG is an abbreviation for Bird-bath Resonator Gyroscope. This micro-vibrator is expected to have higher sensitivity than before because the Q value representing the vibration state reaches 10 6 or more.

[0004] An inertial sensor using this type of micro-vibrator is, for example, the one described in Patent Document 1. In this inertial sensor, a bottomed cylindrical connecting portion extending from near the apex of the substantially hemispherical three-dimensional curved surface of the micro-vibrator toward the inner center of the hemisphere is inserted into a bonding region surrounded by a substantially annular frame on the mounting substrate. This inertial sensor has a surface electrode covering the entire surface of the micro-vibrator and a wiring formed in the bonding region of the mounting substrate joined together, and a predetermined voltage can be applied to the surface electrode of the micro-vibrator via the wiring of the mounting substrate, and the change in the capacitance between the micro-vibrator and a plurality of electrode portions surrounding it can be detected. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] U.S. Patent Application Publication No. 2009 / 0094024 [Overview of the project] [Problems that the invention aims to solve]

[0006] In the inertial sensor described in Patent Document 1, only the bottom surface of the connection portion of the micro-vibrating body is bonded to the wiring of the mounting substrate. As a result, the bonding strength is low, and there is a risk that the micro-vibrating body may detach from the mounting substrate if any external impact is applied. To suppress the detachment between the micro-vibrating body and the mounting substrate, it is conceivable to use a bonding material such as sintered silver to bond not only the bottom surface of the connection portion of the micro-vibrating body, but also the side surface near the bottom surface of the connection portion and the substantially annular frame of the mounting substrate.

[0007] However, when joining the micro-vibrator to the mounting substrate, the joining member moves upward along the roughly annular frame. If there is an unevenness in this upward movement, variations will occur in the height of the joining member that fixes the side surface of the connection part of the micro-vibrator. When such variations occur, there will be a difference in the degree of fixation between the parts of the micro-vibrator where the joining member is high and the parts where it is low on the side surface of the connection part. When the micro-vibrator is vibrated, the vibration will not be symmetrical, and the sensitivity of the inertial sensor will decrease.

[0008] In view of the above, the present invention aims to provide an inertial sensor in which a micro-vibrating body and a mounting substrate are joined by a bonding member, thereby ensuring the bonding strength between them while also ensuring the symmetry of the vibration of the micro-vibrating body during operation. [Means for solving the problem]

[0009] To achieve the above objective, the inertial sensor described in claim 1 comprises a micro-vibrating body (2) having a curved surface portion (21) having a hemispherical three-dimensional curved surface and a bottomed cylindrical connecting portion (22) extending from the curved surface portion toward the center of the hemisphere; a mounting substrate (3) having a frame-shaped inner frame portion (51) surrounding the joining region, with the region located directly below the connecting portion being the joining region; a joining member (52) joining the connecting portion and the inner frame portion; and a frame-shaped annular member (6) attached to the side of the connecting portion, with the surface of the connecting portion facing the mounting substrate being the mounting surface (22b) and the surface adjacent to the mounting surface being the side surface (22c), wherein the annular member covers the entire region of the mounting substrate located between the inner frame portion and the connecting portion, and the joining member covers the entire inner wall surface (51b) of the inner frame portion and is in contact with the annular member.

[0010] As a result, an annular member is attached to the side of the connection part of the micro-vibrator, and when the connection member crawls up along the inner frame during bonding between the micro-vibrator and the mounting substrate, the annular member blocks the flow of the connection member, resulting in an inertial sensor structure. Therefore, this inertial sensor ensures the bonding strength between the micro-vibrator and the mounting substrate, and the height of the connection member on the side of the connection part is made uniform, ensuring the symmetry of the vibration of the micro-vibrator during operation.

[0011] The reference numerals in parentheses attached to each component indicate an example of the correspondence between that component and the specific components described in the embodiments described later. [Brief explanation of the drawing]

[0012] [Figure 1] This is a perspective cross-sectional view showing an example of an inertial sensor according to an embodiment. [Figure 2] This is a cross-sectional view showing a micro-vibrating body and an annular member attached thereto. [Figure 3] This is a cross-sectional view between III-III in Figure 1. [Figure 4] This is a perspective view showing an example of an annular member. [Figure 5]It is a flowchart showing the mounting process of the micro-vibrator among the manufacturing processes of the inertial sensor according to the embodiment. [Figure 6] It is a cross-sectional view showing the process of preparing the mounting substrate and the annular member among the mounting processes of the inertial sensor according to the embodiment. [Figure 7] It is a cross-sectional view showing the process following FIG. 6. [Figure 8] It is a cross-sectional view showing the process following FIG. 7. [Figure 9] It is a cross-sectional view showing the process following FIG. 8. [Figure 10] It is a cross-sectional view showing the process following FIG. 9. [Figure 11] It is a cross-sectional view showing the process following FIG. 10.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described based on the drawings. In the following embodiments, parts that are the same or equivalent to each other are denoted by the same reference numerals and will be described.

[0014] (Embodiment) The inertial sensor 1 according to the embodiment will be described with reference to the drawings.

[0015] In FIG. 1, in order to make the configuration of the inertial sensor 1 easy to understand, a part of the lower substrate 4, the upper substrate 5, the annular member 6, and the micro-vibrator 2, which will be described later, of the inertial sensor 1 is omitted, and the cross-sectional configuration of the micro-vibrator 2 is partially shown. In FIG. 3, in order to make the configuration of the inertial sensor 1 easy to understand, the outlines of the electrode portion 53 and the electrode film 531, which are located in a different cross-section and will be described later, are shown by broken lines.

[0016] Hereinafter, for the convenience of explanation, as shown in FIG. 1, one direction in the plane formed by the mounting substrate 3 is referred to as the "x direction", the direction orthogonal to the x direction on the same plane is referred to as the "y direction", and the normal direction to the xy plane is referred to as the "z direction", respectively. The x, y, and z directions in the figures after FIG. 2 respectively correspond to the x, y, and z directions in FIG. 1. Also, in this specification, "up" means the direction along the z direction in the figure, meaning the arrow side, and "down" means the opposite side of up. Furthermore, in this specification, the state of viewing the inertial sensor 1, the micro-vibrator 2, or the mounting substrate 3 from the upper side in the z direction may be referred to as "top view".

[0017] As shown in FIG. 1 for example, the inertial sensor 1 according to the embodiment is preferably configured such that the micro-vibrator 2 is mounted on the mounting substrate 3 and used to form an inertial sensor such as a gyro sensor like a BRG, but can also be adopted for other applications such as a clock device. In this specification, the case where the inertial sensor 1 is a BRG will be described as a representative example, but it is not limited to this application.

[0018] 〔Inertial Sensor〕 An example of the inertial sensor 1 having the micro-vibrator 2 will be described. As shown in FIG. 1 for example, the inertial sensor 1 includes a micro-vibrator 2, a mounting substrate 3, and an annular member 6, and a part of the micro-vibrator 2 is joined to the mounting substrate 3. The inertial sensor 1 is configured to detect the angular velocity applied to the inertial sensor 1 based on the change in capacitance between the curved surface portion 21 of the thin micro-vibrator 2 that can vibrate in the wine glass mode and a plurality of electrode portions 53 on the mounting substrate 3.

[0019] As shown in FIG. 2 for example, the micro-vibrator 2 includes a curved surface portion 21 including the outer shape of a substantially hemispherical three-dimensional curved surface, a connecting portion 22 extending from the vertex side of the virtual hemisphere formed by the curved surface portion 21 toward the center side of the hemisphere, and a surface electrode 23 covering the front and back surfaces thereof. For example, the micro-vibrator 2 has a curved surface portion 21 having a bowl-shaped three-dimensional curved surface, and the Q value of its vibration is 10 5 or more.

[0020] The micro-vibrator 2, for example, has a base portion having a curved surface portion 21 and a connecting portion 22, which is made of a reflow material such as quartz glass, borosilicate glass, or other additive-containing glass, metallic glass, or silicon. The base portion of the micro-vibrator 2 is not limited to the above-mentioned material examples, as long as it is made of a reflow material that can form the three-dimensional curved surface portion 21 and the connecting portion 22 and can vibrate in wine glass mode. The micro-vibrator 2 is formed, for example, by processing a thin substrate made of the above-mentioned material through a forming process described later, resulting in a thin-walled member with a thickness of 10 μm to 100 μm on the order of micrometers for the curved surface portion 21 and the connecting portion 22. The micro-vibrator 2 has a millimeter-sized shape, for example, with a height dimension of 2.5 mm in the direction along the thickness direction of the mounting substrate 3, and an outer diameter of 5 mm on the surface 2a side of the rim 211 described later.

[0021] The micro-vibrating body 2 is formed by setting a quartz plate with a thickness of 100 μm or less in a mold (not shown) which has a recess and a support column that supports a part of the quartz plate at the center of the recess when it is heated and softened. The curved surface portion 21 is formed by softening the quartz plate with a heating means such as a flame and vacuuming the inside of the recess. For example, in this process, the part of the quartz plate supported by the support column of the mold (not shown) becomes a connection portion 22 that is recessed in a bottomed cylindrical shape relative to the curved surface portion 21, and the part that protrudes outward from the recess remains unprocessed but is removed in a later process. Then, for example, the recess of the mold (not shown) is returned to atmospheric pressure, and the quartz plate with the roughly hemispherical curved surface portion 21 formed is removed from the mold, and the quartz plate is sealed with a sealant made of any curable resin material. After that, for example, unnecessary parts of the quartz plate after processing, along with the sealant, are removed by polishing and CMP, and then all the sealant is removed by any method such as heating or chemical solution, and the quartz plate is taken out. CMP is an abbreviation for Chemical Mechanical Polishing. The base of the micro-vibrator 2 is manufactured, for example, by the manufacturing process described above, but is not limited to this example, and other known methods may be employed. For example, the base of the micro-vibrator 2 may be formed by removing the unnecessary portion outside the curved portion 21 by laser processing without sealing the quartz plate on which the curved portion 21 and the connecting portion 22 are formed. Subsequently, the micro-vibrator 2 can be manufactured by depositing a surface electrode 23 on the base of the micro-vibrator 2 by any film deposition method.

[0022] The end of the curved portion 21 opposite to the connecting portion 22 is designated as a rim 211, and the rim 211 is, for example, roughly cylindrical in shape. Here, "roughly cylindrical shape" includes not only cylindrical shapes where the diameter from the upper end to the lower end of the outer and inner surfaces of the rim 211 is the same, but also cylindrical shapes where the diameter from the upper end to the lower end varies. In other words, the curved portion 21 has a configuration in which the rim 211 is an annular portion of an annular curved surface. The micro-vibrating body 2 is mounted on the mounting substrate 3 with the side with the larger outer diameter as the front surface 2a and the opposite side as the back surface 2b, so that the rim 211 is mounted so that the front surface 2a side faces the multiple electrode portions 53 on the mounting substrate 3, and the intervals between the multiple electrode portions 53 are equal. When the micro-vibrating body 2 is mounted on the mounting substrate 3, the curved portion 21 including the rim 211 is a hollow state in which it does not come into contact with other components. When the micro-vibrator 2 is mounted on the substrate 3, the hollow rim 211 has a structure that allows it to vibrate in wineglass mode.

[0023] The connection portion 22 is a connection part that connects to other components such as the mounting substrate 3, and is, for example, a bottomed cylindrical recess. The bottom surface 22a of the recess on the surface 2a side of the connection portion 22 can be, for example, a suction surface used for suction transport when mounting the micro-vibrating body 2 onto the mounting substrate 3. The surface of the connection portion 22 opposite to the bottom surface 22a of the recess, i.e., the back surface 2b side, is the mounting surface 22b that faces the mounting substrate 3. An annular member 6 is attached to the side surface of the connection portion 22 on the back surface 2b side.

[0024] The surface electrode 23 is composed of a laminated film of Cr (chromium) or Ti (titanium) from the substrate side and any conductive material such as Au (gold) or Pt (platinum), although this is not limited to the above. The surface electrode 23 is deposited on the surface 2a and back surface 2b of the micro-vibrator 2 by any deposition method such as sputtering, vapor deposition, CVD, or ALD. CVD is an abbreviation for Chemical Vapor Deposition. ALD is an abbreviation for Atomic Layer Deposition. The surface electrode 23 is deposited on at least the mounting surface 22b and the surface 2a of the rim 211, and these parts are electrically connected. The surface electrode 23 may be a solid shape covering the entire front and back surfaces of the micro-vibrator 2, or it may be a patterned shape covering a part of the front and back surfaces by patterning using a photolithography etching method or the like. The micro-vibrator 2 is connected to the mounting substrate 3 via a bonding member 52 made of a conductive material, where the portion of the surface electrode 23 covering the mounting surface 22b of the connection portion 22 is, for example, the connection member 52 made of a conductive material.

[0025] The mounting substrate 3, as shown in Figure 1 for example, comprises a lower substrate 4 and an upper substrate 5, which are joined together. For example, the mounting substrate 3 can be obtained by etching and forming a wiring film on a lower substrate 4 made of borosilicate glass, an insulating material, then anodic bonding an upper substrate 5 made of silicon (Si), a semiconductor material, to the lower substrate 4, and then patterning. The mounting substrate 3, for example, comprises on the upper substrate 5 side a plurality of inner frame portions 51, a plurality of electrode portions 53 arranged apart from each other so as to surround the inner frame portions 51, and an outer frame portion 54 that surrounds the electrode portions 53 away from them. The mounting substrate 3 also comprises on the lower substrate 4 side a ring-shaped groove 41 that surrounds the plurality of inner frame portions 51 while separating the inner frame portions 51 from the plurality of electrode portions 53, and a plurality of wirings 42 that span the inside and outside of the groove 41.

[0026] The groove 41 is, for example, a groove provided between the inner frame portion 51 and the plurality of electrode portions 53, as shown in Figure 3, and is formed by wet etching. The groove 41 is sized to correspond to the outer diameter of the rim 211 of the micro-vibrator 2 and is provided to prevent the rim 211 from coming into contact with the mounting substrate 3 when the micro-vibrator 2 is mounted on the mounting substrate 3.

[0027] The 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 of the multiple electrode portions 53. Multiple wirings 42 are provided, and on the lower substrate 4, they straddle the groove 41, with one end connected to the inner frame portion 51 and the other end connected to the outer frame portion 54, and these are electrically connected. As a result, the mounting substrate 3 can apply voltage to the surface electrodes 23 of the micro-vibrator 2 via the outer frame portion 54, the wiring 42, and the inner frame portion 51.

[0028] The inner frame portion 51 is formed, for example, by performing dry etching such as DRIE on the upper substrate 5 which is anodic-bonded to the lower substrate 4, together with multiple electrode portions 53 and the outer frame portion 54. DRIE is an abbreviation for Deep Reactive Ion Etching. The inner frame portion 51 is, for example, an annular shape when viewed from above, and is configured so that the connection portion 22 of the micro-vibrator 2 can be inserted into the enclosed area. In other words, the inner frame portion 51 is a frame shape that surrounds the bonding area, which is the area of ​​the mounting substrate 3 located directly below the mounting surface 22b of the micro-vibrator 2. For example, after placing the bonding member 52 in the area of ​​the mounting substrate 3 enclosed by the inner frame portion 51, the connection portion 22 of the micro-vibrator 2 is mounted on the bonding member 52, and then heated and solidified to mount the micro-vibrator 2 onto the mounting substrate 3.

[0029] The bonding member 52 is made of a conductive material such as sintered silver, and fixes the connection portion 22 of the micro-vibrator 2 to the mounting substrate 3. The bonding member 52 fixes the micro-vibrator 2 to the mounting substrate 3 while covering the mounting surface 22b of the connection portion 22 and a portion of the side surface 22c adjacent to the mounting surface 22b. The bonding member 52 can be made of any conductive material that can bond to the micro-vibrator 2 and the surface electrode 23, but it is preferable to use a material that does not contain resin material components, such as a sintered material, rather than a paste material that contains resin material components. This allows the Young's modulus of the bonding member 52 to be increased, and outgassing due to resin components is suppressed, thereby suppressing a decrease in the sensitivity of the inertial sensor 1. The bonding member 52 is made, for example, by a manufacturing process described later, so that it covers at least the entire inner wall surface 51b on the connection portion 22 side of the inner frame portion 51, and is in contact with the annular member 6, and covers a portion of the upper surface 51a of the inner frame portion 51.

[0030] The multiple electrode portions 53 are arranged apart from each other, and, as shown in Figure 3, for example, an electrode film 531 is formed on the upper surface of each. The potential of the multiple electrode portions 53 can be controlled by, for example, wires (not shown) being connected to the electrode film 531 and electrically connecting them to an external circuit board (not shown). The multiple electrode portions 53 are arranged apart from each other at equal intervals, for example, in a top view, surrounding the rim 211 of the micro-vibrator 2 and forming a ring in the xy plane. When the micro-vibrator 2 is mounted, each of the multiple electrode portions 53 is at a predetermined distance from the rim 211 of the micro-vibrator 2, and each forms a capacitor with the micro-vibrator 2. In other words, the mounting substrate 3 can detect the capacitance between itself and the micro-vibrator 2 via the multiple electrode portions 53, generate an electrostatic attraction between itself and the micro-vibrator 2, and vibrate the micro-vibrator 2 in wineglass mode. In other words, of the multiple electrode portions 53, some are detection electrodes that detect capacitance, and the remaining portions are drive electrodes that drive the micro-vibrating body 2.

[0031] The outer frame portion 54 is, for example, a single frame shape that surrounds the inner frame portion 51 and a plurality of electrode portions 53 arranged around it when viewed from above. The outer frame portion 54 is, for example, provided with at least one electrode film 541 made of Al or the like on its upper surface, to which a wire (not shown) is connected.

[0032] The annular member 6 is, for example, positioned above the upper surface 51a of the inner frame 51 in the z direction and is an auxiliary member positioned to equalize the upward movement of the joining member 52 within the space enclosed by the inner frame 51 when joining the micro-vibrator 2 and the mounting substrate 3. Specifically, the annular member 6 is pre-attached to the side surface 22c of the connection portion 22 before joining the micro-vibrator 2 and the mounting substrate 3, and by blocking the upward flow of the joining member 52 in the z direction when joining the micro-vibrator 2 and the mounting substrate 3, it equalizes the upward movement of the joining member 52. The annular member 6 is, for example, ring-shaped as shown in Figure 4 and covers the entire area of ​​the mounting substrate 3 located between the inner frame 51 and the side surface 22c of the connection portion 22 of the micro-vibrator 2, as shown in Figure 3. The annular member 6 is in close contact with the side surface 22c of the connection portion 22 in order to reduce the influence on the vibration characteristics of the curved surface portion 21, but is not chemically bonded. The annular member 6 is made of a resin material that has heat resistance to a temperature higher than the melting point of the bonding member 52, for example, 250°C or higher, from the viewpoint of suppressing thermal degradation during the bonding process using the bonding member 52. In other words, the annular member 6 is made of a resin material that can withstand the temperature during the bonding process between the micro-vibrator 2 and the mounting substrate 3 using the bonding member 52.

[0033] The annular member 6 is made of a fluororesin material such as PTFE or a silicon-based resin material, and is shrunk by heating or the like before the joining process using the joining member 52, so that it is in the close contact state with the micro-vibrating body 2 as described above. PTFE is an abbreviation for polytetrafluoroethylene.

[0034] In addition to the above, the annular member 6 may be made of an elastically deformable resin material, and its inner diameter before being attached to the side surface 22c of the connecting portion 22 may be smaller than the outer diameter of the side surface 22c, so that it is attached to the side surface 22c of the connecting portion 22 by physical contraction, i.e., restoring force. In this case, the annular member 6 may be made of a resin material such as fluororubber (FKM) or silicone rubber.

[0035] From the viewpoint of reducing the influence on the vibration characteristics of the micro-vibrating body 2, it is preferable that the annular member 6 be made of a material with a lower Young's modulus than the micro-vibrating body 2 and the joining member 52, i.e., a softer material. This is because if the Young's modulus is close to that of the micro-vibrating body 2 and the joining member 52, the annular member 6 will affect the vibration, and the symmetry of the annular member itself will be required.

[0036] The annular member 6 may be any frame shape that covers the entire area between the inner frame portion 51 and the side surface 22c of the connecting portion 22, and the outer casing does not have to be circular and can be appropriately changed to other shapes besides the annular shape. The annular member 6 can also be obtained, for example, by a known resin molding method. Furthermore, the annular member 6 may be made of any material that does not chemically bond with the base portion and surface electrode 23 of the micro-vibrating body 2, and is not limited to the material examples described above, and may be appropriately changed depending on the material of the base portion and surface electrode 23.

[0037] The above describes the basic configuration of the inertial sensor 1 equipped with a micro-vibrating body 2. The inertial sensor 1 is manufactured, for example, by preparing a micro-vibrating body 2 and a mounting substrate 3, applying a bonding member 52 to the mounting substrate 3 held by a mounting device (not shown), and then using a transfer device (not shown) to adsorb and transfer the micro-vibrating body 2 and heat-bonding it.

[0038] It should be noted that the inertial sensor 1 described above is merely an example, and the number, shape, dimensions, and arrangement of the wiring 42, inner frame 51, electrode 53, and outer frame 54 on the mounting substrate 3 on which the micro-vibrator 2 is mounted may be changed as appropriate. For example, if the micro-vibrator 2 obtained by removing the unnecessary portion of the base 20 by the laser processing described above has a configuration in which the lower end of the rim 211 is positioned above the mounting surface 22b in the z direction, the mounting substrate 3 may have a configuration without grooves 41. Furthermore, the outer frame 54 only needs to function as a second electrode section that is electrically connected to the micro-vibrator 2 with multiple electrode sections 53 as first electrode sections and capable of applying voltage to the surface electrodes 23 of the micro-vibrator 2, and does not necessarily have to be a frame shape, and its shape and arrangement can be changed as appropriate.

[0039] [Joining process for micro-vibrating bodies] Next, the process of bonding the micro-vibrator 2 to the mounting substrate 3, which is part of the manufacturing process of the inertial sensor 1, will be explained with reference to Figures 5 to 11.

[0040] For example, while preparing the micro-vibrator 2 and the mounting substrate 3 using the method described above, the annular member 6 is prepared in step S110 as shown in Figure 5. Then, for example as shown in Figure 6, the prepared annular member 6 is placed on the upper surface 51a of the inner frame portion 51 of the mounting substrate 3. At this time, for example, the mounting substrate 3 is held in place by a mounting device (not shown).

[0041] Next, in step S120, for example as shown in Figure 7, the micro-vibrating body 2 is transported by a transport device having a vacuum suction mechanism (not shown) and placed on the mounting substrate 3 so that the mounting surface 22b of the connecting portion 22 is located in the center of the area enclosed by the inner frame portion 51 of the mounting substrate 3. At this time, the mounting substrate 3 does not yet have the joining member 52 placed on it. The alignment of the micro-vibrating body 2 and the mounting substrate 3 can be achieved, for example, by imaging the micro-vibrating body 2 during transport using an imaging device (not shown), extracting feature points of the curved portion 21 by edge detection using known image recognition technology, and adjusting the relative position based on these feature points.

[0042] In the next step S130, the annular member 6 is fixed to the side surface 22c of the connection portion 22 of the micro-vibrator 2. Specifically, for example, if the annular member 6 is made of a resin material that shrinks when heated, the mounting substrate 3 is heated to a higher temperature than the bonding process by the bonding member 52 using the heating mechanism of a mounting device (not shown), causing the annular member 6 to shrink due to heat. For example, if the annular member 6 is made of PTEF, by performing a heat treatment at 327°C for 10 minutes, the annular member 6 can be brought into close contact with the side surface 22c of the connection portion 22 of the micro-vibrator 2, as shown in Figure 8.

[0043] Furthermore, if the annular member 6 is made of an elastically deformable resin material, it is held in an expanded state using a jig (not shown) such that the inner diameter of the annular member 6 is larger than the outer diameter of the side surface 22c of the connection portion 22. After the micro-vibrator 2 is placed on the mounting substrate 3, the holding of the annular member 6 by the jig (not shown) is released, and the annular member 6 is returned to its inner diameter before it was fixed to the jig, i.e., a diameter smaller than the outer diameter of the side surface 22c of the connection portion 22. As a result, a restoring force acts on the annular member 6, causing it to be in close contact with the side surface 22c of the connection portion 22 of the micro-vibrator 2.

[0044] As described above, the annular member 6 is fixed to the micro-vibrating body 2 by means of heating or mechanical means, for example, but the method of fixing is arbitrary and can be changed as appropriate depending on the constituent material of the annular member 6.

[0045] Next, in step S140, for example as shown in Figure 9, the micro-vibrating body 2 to which the annular member 6 is fixed is transported by a transport device (not shown) and temporarily separated from the mounting substrate 3. Then, in step S150, the bonding member 52 is placed in the area of ​​the mounting substrate 3 surrounded by the inner frame portion 51.

[0046] In the next step, S160, the micro-vibrating body 2 is re-placed onto the mounting substrate 3 on which the joining member 52 is positioned using a transport device (not shown), for example, as shown in Figure 10. At this time, the annular member 6 is positioned with a gap between it and the upper surface 51a of the inner frame portion 51, as the micro-vibrating body 2 is lifted from the mounting substrate 3 by the thickness of the joining member 52.

[0047] Next, in step S170, the mounting substrate 3 is heated by a heating mechanism (not shown) to heat and solidify the bonding member 52, thereby bonding the micro-vibrator 2 and the mounting substrate 3. For example, when sintered silver is used as the bonding member 52, the micro-vibrator 2 is pressed against the mounting substrate 3 by a transport device (not shown), and the bonding member 52 is sintered by heating at 250°C for 30 minutes. At this time, the bonding member 52 crawls up along the inner wall surface 51b of the inner frame portion 51 due to the pressure from the micro-vibrator 2, as shown in Figure 11, for example. The crawled-up bonding member 52 is then prevented from moving further upward in the z direction by the annular member 6 attached to the micro-vibrator 2, and flows along the upper surface 51a in the xy plane. As a result, as shown in Figure 3, the bonding member 52 solidifies after the height of the portion covering the side surface 22c of the connection portion 22 is made uniform while covering the entire inner wall surface 51b of the inner frame portion 51.

[0048] The above describes the basic steps for attaching the annular member 6 to the micro-vibrating body 2 and joining the micro-vibrating body 2 to the mounting substrate 3.

[0049] According to this embodiment, an annular member 6 is attached to the side surface 22c of the connection portion 22 of the micro-vibrator 2, and the annular member 6 covers the entire area between the inner frame portion 51 and the connection portion 22 of the mounting substrate 3, thereby suppressing height variations in the portion of the joining member 52 that covers the side surface 22c. As a result, while ensuring the bonding strength between the micro-vibrator 2 and the mounting substrate 3, variations in the degree of fixation of the side surface 22c of the micro-vibrator 2 are suppressed, thereby ensuring the symmetry of the vibration of the micro-vibrator 2 during operation, and consequently resulting in an inertial sensor 1 with improved sensor sensitivity.

[0050] Furthermore, by attaching the annular member 6 to the micro-vibrator 2 beforehand and then joining it to the mounting substrate 3 with the joining member 52, the flow of the joining member 52 can be controlled, resulting in an inertial sensor 1 with reduced height variation in the portion of the joining member 52 that covers the side surface 22c. In addition, by using the annular member 6, it becomes unnecessary to perform separate processing on the micro-vibrator 2 in order to control the flow of the joining member 52, thereby preventing a deterioration in the vibration characteristics of the micro-vibrator 2. Moreover, by constructing the annular member 6 from a material with a lower Young's modulus than the base of the micro-vibrator 2 or the joining member 52, or from a material that does not chemically bond with the micro-vibrator 2, the influence on the vibration characteristics of the micro-vibrator 2 can be reduced, resulting in a highly sensitive inertial sensor 1.

[0051] Furthermore, when a material without resin components is used as the joining member 52, variations in the rigidity of the joining member 52 are suppressed, and the influence on the vibration characteristics of the micro-vibrating body 2 is reduced, resulting in a highly sensitive inertial sensor 1.

[0052] (Other embodiments) This disclosure is described in accordance with the embodiments, but it is understood that this disclosure is not limited to such embodiments or structures. This disclosure also includes various modifications and variations within the equivalence range. In addition, various combinations and forms, as well as other combinations and forms including one, more, or less of those elements, fall within the scope and concept of this disclosure.

[0053] It goes without saying that, in each of the above embodiments, the elements constituting the embodiment are not necessarily essential unless explicitly stated to be particularly essential or unless they are clearly considered essential in principle. Furthermore, in each of the above embodiments, when numerical values ​​such as the number, numerical values, quantities, or ranges of the components of the embodiment are mentioned, the embodiment is not limited to those specific numbers unless explicitly stated to be particularly essential or unless it 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 are mentioned, the embodiment is not limited to those shapes, positional relationships, etc., unless explicitly stated or unless it is clearly limited to a specific shape, positional relationship, etc., in principle. [Explanation of symbols]

[0054] 2 Micro vibrator 21 Curved part 22 Connection part 22b Implementation side 22c side 3. Implemented circuit board 51 Inner frame section 51b Inner wall surface 52 Joining members 6. Annular member

Claims

1. It is an inertial sensor, A micro-vibrating body (2) having a curved surface portion (21) having a hemispherical three-dimensional curved surface, and a bottomed cylindrical connecting portion (22) extending from the curved surface portion toward the center of the hemispherical shape, The mounting substrate (3) has a frame-shaped inner frame portion (51) surrounding the joining region, with the region located directly below the connection portion being defined as the joining region. A joining member (52) that joins the connecting portion and the inner frame portion, The connection portion includes a mounting surface (22b) on the side facing the mounting substrate, a side surface (22c) adjacent to the mounting surface, and a frame-shaped annular member (6) attached to the side surface. The annular member covers the entire region of the mounting substrate located between the inner frame portion and the connecting portion. The joining member covers the entire inner wall surface (51b) of the inner frame and is in contact with the annular member, and is an inertial sensor.

2. The inertial sensor according to claim 1, wherein the annular member is made of a material with a lower Young's modulus than the joining member.

3. The inertial sensor according to claim 2, wherein the annular member is made of a resin material that shrinks with heat.

4. The inertial sensor according to claim 2, wherein the annular member has an inner diameter smaller than the outer diameter of the side surface before being attached to the connecting portion and is made of an elastically deformable resin material.

5. The resin material has heat resistance of 250 degrees or higher, as described in claim 3 or 4, for the inertial sensor.

6. The inertial sensor according to claim 1, wherein the annular member is in close contact with the side surface and is not chemically bonded to the micro-vibrating body.

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