JP7533285B2 - Inertial sensor and method for manufacturing the same - Google Patents

Description

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

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 level will be required.

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

US Patent Application Publication No. 2019/0094024A1

This micro-vibrator is made of, for example, quartz or the like with a thickness of several tens of micrometers, so it must be handled carefully to avoid scratching it when mounting it on a mounting board. If the base material (e.g., quartz) that forms the base of the micro-vibrator or the electrode film formed on its surface is scratched or peeled off, the Q value decreases, and the sensitivity of the gyro sensor decreases.

The BRG described in Patent Document 1 is manufactured by forming a movable jig for positioning the micro-vibrator as part of the mounting substrate, placing the micro-vibrator on the mounting substrate, adjusting the position of the micro-vibrator with the movable jig, and then bonding the micro-vibrator to the mounting substrate with a bonding member. The portion of the mounting substrate that is the movable jig is then released and removed from the mounting substrate by a process such as etching.

Although this method can ensure the positioning accuracy of the micro-vibrator on the mounting board, it requires many processes and there is a risk of increasing manufacturing costs. Therefore, there is a need to simplify the positioning of the micro-vibrator on the mounting board without damaging the micro-vibrator.

In addition, in the above-mentioned BRG, a bonding material is placed inside the frame-shaped mounting portion of the mounting substrate, and the bonding material is melted and solidified to bond the micro-vibrator to the mounting substrate. At this time, the molten bonding material causes the micro-vibrator to temporarily float, which may cause the micro-vibrator to tilt, so it is necessary to suppress the tilt of the micro-vibrator. However, Patent Document 1 does not mention how to suppress the tilt of the micro-vibrator when it is bonded.

In view of the above, the present invention aims to provide an inertial sensor equipped with this type of micro-vibrator that can simultaneously simplify the positioning of the micro-vibrator when mounting the micro-vibrator on a mounting substrate and suppress tilt caused by a bonding member.

In order to achieve the above object, the inertial sensor described in claim 1 includes a micro-vibrator (2) having a curved surface portion (21) with an annular curved surface and a recess (22) recessed from the curved surface portion, a frame-shaped inner peripheral frame (511) into which the recess of the micro-vibrator is fitted, a frame-shaped outer peripheral frame (512) surrounding the inner peripheral frame, and an upper substrate (5) having a plurality of electrode portions (53) arranged to surround the outer peripheral frame while being spaced apart from each other, and a mounting substrate (3) formed by joining the upper substrate (5) to a lower substrate (4), and a joining member (52) at least a part of which is arranged inside the inner peripheral frame and joins the micro-vibrator and the mounting substrate, the curved surface portion of the micro-vibrator being hollow, and the mounting substrate is provided at least in the region inside the inner peripheral frame of the lower substrate or in the inner peripheral frame, and has an escape groove (43, 55, 56) into which the excess part of the joining member arranged inside the inner peripheral frame flows.

This results in an inertial sensor in which the recess of the micro-vibrator, which has a curved surface and a recess, is fitted into the inner peripheral frame of a mounting substrate formed by joining an upper substrate and a lower substrate having an outer peripheral frame surrounding the frame-shaped inner peripheral frame into which the recess of the micro-vibrator is fitted, and the inner peripheral frame of the mounting substrate is formed by joining the upper substrate and the lower substrate having an outer peripheral frame surrounding the frame. By having an inner peripheral frame into which the micro-vibrator is fitted, this inertial sensor has a structure in which the positioning accuracy of the micro-vibrator relative to the mounting substrate is equal to or higher than a predetermined level, the positioning process is simplified, and positional deviation of the micro-vibrator after positioning is suppressed.

The inertial sensor also has an escape groove in the lower substrate or inner frame of the mounting substrate, so that the bonding material is placed in the inner region of the inner frame of the mounting substrate, and when the micro-vibrator is bonded, the excess of the molten bonding material flows into the escape groove. This prevents more bonding material than necessary from being interposed between the recess of the micro-vibrator and the bonding surface of the mounting substrate, resulting in an inertial sensor in which tilting of the micro-vibrator is suppressed.

Therefore, this inertial sensor has a structure in which the positioning of the micro-vibrator can be performed easily and with high accuracy, and the positional deviation of the micro-vibrator in the in-plane direction is suppressed, while the tilt of the micro-vibrator during bonding is suppressed.

The manufacturing method of the inertial sensor according to claim 9 is a manufacturing method of an inertial sensor (1) including a micro-vibrator (2) having a curved surface portion (21) with an annular curved surface and a recessed portion (22) recessed from the curved surface portion, a lower substrate (4), and an upper substrate (5) having a frame-shaped inner peripheral frame (511) into which the recessed portion of the micro-vibrator is fitted and joined to the lower substrate, and a mounting substrate (3) to which the recessed portion of the micro-vibrator is joined to the inner region of the inner peripheral frame via a joining member (52), in which the curved surface portion becomes hollow when the micro-vibrator is mounted on the inner peripheral frame. The manufacturing method includes preparing a micro-vibrator, preparing a mounting substrate, arranging a joining member in the inner region of the inner peripheral frame of the mounting substrate, fitting the recessed portion of the micro-vibrator into the inner region of the inner peripheral frame after arranging the joining member, bringing the joining member into contact with the recessed portion of the micro-vibrator, and heating the mounting substrate to melt and solidify the joining member, thereby joining the micro-vibrator to the mounting substrate. In preparing the mounting substrate, a mounting substrate is prepared that has a frame-shaped outer peripheral frame (512) that surrounds the inner peripheral frame, a plurality of electrode portions (53) that are arranged to surround the outer peripheral frame while being spaced apart from each other, and an escape groove (43, 55, 56) that is provided at least in the inner region of the inner peripheral frame or in the inner peripheral frame of the lower substrate. In bonding the micro-vibrator, the recess of the micro-vibrator is pressed against the lower substrate, and the excess portion of the molten bonding material is pushed out into the escape groove.

According to this method, an upper substrate and a lower substrate are joined together, and the upper substrate has an inner peripheral frame surrounding the inner peripheral frame into which the recess of the micro-vibrator is fitted, and a mounting substrate is used in which at least the inner region of the inner peripheral frame of the lower substrate, or an escape groove is formed in the inner peripheral frame. Then, after a bonding material is placed in the inner region of the inner peripheral frame of the mounting substrate, the micro-vibrator is fitted into the inner peripheral frame, and the bonding material is melted and solidified to bond the micro-vibrator. At this time, an excess portion of the molten bonding material is pushed out into the escape groove of the mounting substrate, and an inertial sensor in which the micro-vibrator and the mounting substrate are bonded is manufactured.

By fitting the recess of the micro-vibrator into the inner frame of the mounting board, it is possible to simplify the positioning of the micro-vibrator relative to the mounting board. In addition, by allowing the excess part of the bonding material to escape into the escape groove of the mounting board when bonding the micro-vibrator, it is possible to prevent more bonding material than necessary from being interposed between the recess of the micro-vibrator and the mounting surface of the mounting board, and to suppress tilting of the micro-vibrator.

Therefore, in the manufacture of inertial sensors, it is possible to simplify the positioning of the micro-vibrator while also controlling the inclination of the micro-vibrator using the joining member.

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 an example of a micro-vibrator. 3 is a cross-sectional view showing a cross section 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. 2 is a cross-sectional view showing a cross section taken along line V-V in FIG. 1. 2 is a cross-sectional view showing a cross section taken along line VI-VI in FIG. 1. FIG. 2 is a top view of the layout showing a mounting board before a microvibrator is mounted. 8 is a cross-sectional view showing a cross section taken along line VIII-VIII in FIG. 7. 9 is a cross-sectional view showing a cross section taken along line IX-IX in FIG. 7. 8 is a cross-sectional view showing a cross section taken along line XX in FIG. 7. 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 shows a step following FIG. FIG. 11D is a diagram showing a process following FIG. FIG. 11D shows a step following FIG. FIG. 11B is a diagram showing a process following FIG. 11E. 11A and 11B are diagrams showing how a micro-vibrator is bonded to a mounting substrate of a comparative example. FIG. 12B is a diagram showing a step subsequent to FIG. 12A, and is an explanatory diagram for explaining the occurrence of tilt of the micro-vibrator during bonding. FIG. 11 is a top view showing a layout of a mounting board for the inertial sensor according to the second embodiment. 14 is a cross-sectional view showing a cross section taken along line XIV-XIV in FIG. 13. 14 is a cross-sectional view showing a cross section taken along line XV-XV in FIG. 13. FIG. 11 is a cross-sectional view showing an inertial sensor according to a second embodiment. FIG. 11 is a top view showing a layout of a mounting board for the inertial sensor according to the third embodiment. 18 is a cross-sectional view showing a cross section taken along line XVIII-XVIII in FIG. 17. FIG. 11 is a cross-sectional view showing an inertial sensor according to a third embodiment. FIG. 13 is a top view layout diagram showing a modified example of the mounting board for the inertial sensor according to the third embodiment. 21 is a cross-sectional view showing a cross section taken along line XXI-XXI in FIG. 20. FIG. 13 is a cross-sectional view showing a modified example of the inertial sensor of the third embodiment. FIG. 13 is a top view showing a layout of a mounting board for the inertial sensor according to the fourth embodiment. 24 is a cross-sectional view showing a cross section taken along line XXIV-XXIV in FIG. 23. FIG. 13 is a cross-sectional view showing an inertial sensor according to a fourth embodiment. FIG. 13 is a top layout diagram showing a mounting board for the inertial sensor according to the fifth embodiment. 27 is a cross-sectional view showing a cross section taken along line XXVII-XXVII in FIG. 26. 27 is a cross-sectional view showing a section taken along line XXVIII-XXVIII in FIG. 26.

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 a first 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, which will be described later, the outer periphery of the micro-vibrator 2 that cannot be seen from the angle shown in FIG. 2 is shown with dashed lines. In FIG. 5 and FIG. 6, in order to make it easier to see, the conductive layer 23 shown in FIG. 2, which will be described later, is omitted from the micro-vibrator 2. The omission of the conductive layer 23 to make it easier to see also applies to FIG. 11A and subsequent figures.

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 micro-vibrator 2 capable of vibrating in a wine glass mode and a plurality of electrode portions 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.

As shown in FIG. 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 curved surface portion 21 having a ring-shaped curved surface toward the center side of the hemisphere. As shown in FIG. 3, the micro-vibrator 2 includes an outer surface of the recessed portion 22 that is an adsorption surface 22a used for adsorption and transport when connected to the mounting substrate 3, and an opposite side of the recessed portion 22 to the adsorption surface 22a that is a mounting surface 22b that is connected to the mounting substrate 3. The diameter of the mounting surface 22b of the micro-vibrator 2 corresponds to the diameter of the inner region of a frame-shaped inner peripheral frame 511 of the mounting substrate 3, which will be described later, and is sized to fit into the inner peripheral frame 511 when mounted on the mounting substrate 3. The micro-vibrator 2 includes a rim 211 that is substantially cylindrical so that the rim 211 and the plurality of electrode portions 53 are equally spaced from each other when the inertial sensor 1 is not driven. The micro-vibration body 2 has a curved surface portion 21 that has a three-dimensional, bowl-shaped curved surface, and the Q value of the vibration is, for example, 10 ⁶ or more.

The micro-vibrator 2 is made of materials such as quartz, glass, silicon, and ceramics, 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 thin-walled with a thickness of several tens of μm, such as 20 μm to 80 μm. The micro-vibrator 2 has a millimeter-sized shape with a height dimension of 2.5 mm and a diameter of 5 mm, with the height direction being along the thickness direction of the mounting substrate 3. The surface of the micro-vibrator 2 is covered with a conductive layer 23. The conductive layer 23 is 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, but is not limited to this, and functions as an electrode film.

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 support part M2 that extends in 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, and a through hole M11 is formed on the bottom surface of the recess M1. The cooling body C includes an insertion part C1 into which the mold M is inserted, and an exhaust port C11 for exhaust on the bottom surface of the insertion part 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 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 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 has a shape having a curved surface part 201 having a three-dimensional curved shape of an approximately hemisphere, a recessed part 202 recessed near the center of the curved surface part 201, and a flat end part 203 located at the outer peripheral end of the curved surface part 201.

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 sealing material E made of any curable resin material, as shown in FIG. 4C. Then, for example, the sealing material E is polished and CMP (short for chemical mechanical polishing) is performed from the surface on the end 203 side to remove the end 203 together with the sealing material E, leaving the recessed portion 202. Then, all of the sealing material E is removed by any method such as heating or dissolving using a chemical solution, and the quartz plate 20 is taken out. Finally, a conductive layer 23 is formed on both sides 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 is not limited to the above method, and other known methods may be used. Furthermore, the micro-vibration body 2 may have any shape that allows it to vibrate in wine glass mode, and is not limited to the BR shape.

When the mounting surface 22b side of the recess 22 of the micro-vibrator 2 is bonded to the mounting substrate 3, as shown in Figs. 5 and 6, for example, the three-dimensional curved surface including the rim 211 becomes hollow, and the micro-vibrator 2 is capable of vibrating in wine glass mode. When the micro-vibrator 2 is bonded to the mounting substrate 3, as shown in Fig. 6, for example, the hollow rim 211 is positioned at a distance from the multiple electrode portions 53 of the mounting substrate 3.

The micro-vibrator 2 is mounted on the mounting substrate 3 with a predetermined degree of alignment accuracy or higher by, for example, fitting the recess 22 into the inner peripheral frame 511 (described later) of the mounting substrate 3 shown in FIG. 7, etc., and positional deviation from the mounting substrate 3 in the in-plane direction, i.e., the xy plane direction, is suppressed. Details of this will be described later.

As shown in FIG. 7, the mounting substrate 3 is configured by bonding a lower substrate 4 and an upper substrate 5 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 is configured with a mounting section 51 on which the micro-vibrator 2 is mounted, a plurality of electrode sections 53 arranged at a distance from each other so as to surround the mounting section 51, and a frame-shaped outer frame section 54 arranged to surround the electrode sections 53.

The mounting section 51 is composed of an inner frame 511 in the shape of a frame into which the recess 22 of the micro-vibrator 2 is fitted, and an outer frame 512 in the shape of a frame surrounding the inner frame 511, as shown in FIG. 5, for example. The inner frame 511 and the outer frame 512 are annular in top view, as shown in FIG. 7, for example, but are not limited to this shape as long as they are in the shape of a frame. The inner frame 511 has a size corresponding to the outer dimensions of the recess 22 of the micro-vibrator 2 on its inner side, and is, for example, a size that provides a clearance of about 5 μm to 10 μm when the recess 22 of the micro-vibrator 2 is fitted. The mounting section 51 is a portion where the micro-vibrator 2 is fixed to the mounting substrate 3 by the bonding member 52, and is also a portion used for positioning the micro-vibrator 2, so it serves as a positioning and fixing portion of about the size of the micro-vibrator 2.

As shown in FIG. 7, the mounting substrate 3 has an annular etching groove 41 surrounding the mounting portion 51 at a position on the outer periphery side of the annular outer peripheral frame 512 when viewed from above. As a result, when the micro-vibrator 2 is mounted on the mounting substrate 3, as shown in FIG. 5 and FIG. 6, the curved surface portion 21 including the rim 211 of the micro-vibrator 2 is in a hollow state where it does not contact other parts. The mounting substrate 3 has a bridge wiring 42 that straddles the etching groove 41 of the lower substrate 4, and the mounting portion 51 and the outer frame portion 54 are electrically connected and at the same potential. 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.

For example, as shown in Figs. 5 and 6, the mounting substrate 3 has an inner region of an annular inner frame 511 where a bonding member 52 mainly composed of AuSn (gold tin) or the like is disposed, and the micro-vibrator 2 is bonded via the bonding member 52. As shown in Fig. 8, the mounting substrate 3 has one end of the bridge wiring 42 covered by the inner frame 511, the other end by the outer frame 54, and the intermediate portion between the one end and the other end by the outer frame 512. As a result, when the micro-vibrator 2 is mounted on the mounting substrate 3, the inner frame 511, the outer frame 512, the bridge wiring 42, and the outer frame 54 are electrically connected to the micro-vibrator 2.

As shown in FIG. 7, for example, the mounting substrate 3 has a plurality of clearance grooves 43 formed in an area located inside the outer peripheral frame 512 of the lower substrate 4. As shown in FIG. 9, for example, the mounting substrate 3 has an area surrounded by the inner peripheral frame 511 (hereinafter referred to as the "inner area") and an area between the inner peripheral frame 511 and the outer peripheral frame 512 (hereinafter referred to as the "outer area") communicated by the clearance grooves 43 provided in the lower substrate 4. The clearance grooves 43 are grooves that connect the inner area and the outer area, and are provided to guide the excess portion of the joining member 52 arranged inside the inner peripheral frame 511 from the inner area to the outer area as shown in FIG. 6, and to suppress the micro-vibration body 2 from tilting during joining. Details of this will be described in the manufacturing method of the inertial sensor 1 described later.

In order to prevent uneven flow of the excess molten joining material 52 when joining the micro-vibration body 2, it is preferable that the multiple escape grooves 43 are arranged symmetrically when viewed from above, as shown in FIG. 7, for example, but this is not limited to this. The number, depth, dimensions, etc. of the escape grooves 43 can also be changed as appropriate depending on the dimensions of the micro-vibration body 2 and the inner frame 511, etc. In the portion of the lower substrate 4 where the escape grooves 43 are not provided, an inner region and an outer region are partitioned by the inner frame 511, as shown in FIG. 10.

As shown in FIG. 1 and FIG. 6, the mounting board 3 includes a plurality of electrode parts 53 arranged at a distance from each other so as to surround the mounting part 51 at the outer peripheral side of the etching groove 41. When the micro-vibrator 2 is mounted, the plurality of electrode parts 53 are in a state of being separated from the rim 211 of the micro-vibrator 2 by a predetermined distance, and each of them forms a capacitor with the micro-vibrator 2. The plurality of electrode parts 53 have an electrode film 531 formed on the upper surface, and for example, a wire not shown is connected to the electrode film 531, and is electrically connected to an external circuit board not shown. As a result, the mounting board 3 can detect the electrostatic capacitance between the micro-vibrator 2 and generate electrostatic attraction between the micro-vibrator 2 and vibrate the micro-vibrator 2 in wine glass mode through the plurality of electrode parts 53. As shown in FIG. 1, the plurality of electrode parts 53 have inner and outer peripheral sides each having an arc shape when viewed from above, and when the inner and outer peripheral sides are connected, they are in a state of drawing intermittent circles with different diameters. In other words, the multiple electrode sections 53 are configured by equally dividing a ring surrounding the mounting section 51 at a predetermined interval.

The "inner circumference side" of the mounting substrate 3 means the center side of the inner region surrounded by the inner circumference frame 511 in a top view as shown in FIG. 7, 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 parts 53 are evenly arranged on the mounting substrate 3 so as to form a ring apart from each other, but this is not limited to this, and the number and arrangement of the electrode parts 53 can be changed as appropriate depending on the shape and size of the micro-vibration body 2.

As shown in FIG. 7 and FIG. 8, each outer frame portion 54 has an electrode film 541 made of Al or the like on its upper surface, and a wire (not shown) is connected to the electrode film 541, and the electrode film 541 is electrically connected to an external circuit board (not shown). This makes it possible for the mounting board 3 to control the potential of the micro-vibrator 2 to a desired value via the outer frame portion 54 using an external power source (not shown) connected to the electrode film 541.

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 a circular etching groove 41 and a number of escape grooves 43 are 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 a film formed by sputtering Al. 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 are formed in the Si substrate by a known etching method to define the areas that will later become the inner peripheral frame 511, the outer peripheral frame 512, the electrode portion 53, and the outer frame portion 54.

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 peripheral frame 511, the outer peripheral frame 512, the electrode portion 53, and the outer frame portion 54. As a result, the Si substrate becomes the upper substrate 5 having the mounting portion 51, the multiple electrode portions 53, and the outer frame portion 54, which are spaced apart from each other. Furthermore, this process results in the multiple clearance grooves 43 formed in the lower substrate 4 being arranged to straddle the inner peripheral frame 511 when viewed from above.

Finally, electrode films 531, 541 are formed on the upper surfaces of the multiple electrode portions 53 and the outer frame portion 54 by a vacuum film formation method such as sputtering. As a result of this process, the mounting substrate 3 having the above-mentioned structure is obtained. Then, when mounting the micro-vibrator 2 on the mounting substrate 3, a plate-shaped member mainly composed of, for example, AuSn is placed as the bonding member 52 in the inner area surrounded by the inner frame 511.

Note that one mounting substrate 3 shown in FIG. 7 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.

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.

In the manufacture of the inertial sensor 1, by using a mounting substrate 3 having a mounting section 51 consisting of an inner peripheral frame 511 and an outer peripheral frame 512 and an escape groove 43, it is possible to easily ensure both the positioning accuracy of the micro-vibrator 2 relative to the mounting substrate 3 and the suppression of tilt.

[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 11F. 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 11F correspond to the cross-sectional view shown in Figure 9. Also, for ease of viewing, Figures 11C to 11F simply show only a portion of the pickup mechanism 300 (described later), and show the inside of the collet 302 with dashed lines.

First, as shown in FIG. 11A, for example, a micro-vibrator 2 and a mounting substrate 3 manufactured by the above method are prepared. Then, as shown in FIG. 11B, for example, a bonding member 52 is placed in the inner area surrounded by an inner peripheral frame 511. For example, a conductive bonding material such as an AuSn plate material, Au paste, or Ag (silver) paste is used as the bonding member 52, and in the case of a plate material, it is placed by using tweezers (not shown), or in the case of a paste, it is applied using a syringe, or the like.

In addition, it is preferable to use a plate-shaped member made of AuSn or the like as the joining member 52 from the viewpoint of stabilizing the joining process of the micro-vibrator 2 and reducing outgassing. When the joining member 52 is a plate-shaped member, it is possible to prevent a part of the joining member 52 from flowing excessively into the escape groove 43 before the micro-vibrator 2 is fitted into the inner peripheral frame 511, and the joining process of the micro-vibrator 2 described later is stabilized. In addition, by using a plate-shaped member as the joining member 52, the amount of outgas generated from the joining member 52 can be reduced in the vacuum sealing described later after the micro-vibrator 2 is joined to the mounting substrate 3, compared to the case where a paste material is used. When a plate-shaped member is used as the joining member 52, for example, a plate-shaped formed solder having a composition of Au80%Sn20% and a thickness of about 50 μm to 200 μm can be used. The thickness of the joining member 52 may be equal to or less than the thickness of the inner peripheral frame 511, and is not limited to the above example and can be changed as appropriate.

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 of the recess 22 of the micro-vibration body 2, and the micro-vibration body 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 suctioned. For example, the maximum diameter of the collet 302 of the pickup mechanism 300 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 length of the collet 302 of the pickup mechanism 300 is greater than the depth of the recess 22 of the micro-vibration body 2, and when the collet 302 is inserted into the recess 22 of the micro-vibration body 2, the collet 302 does not come into contact with anything other than the suction surface 22a of the micro-vibration body 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. As a result, a portion of the bonding member 52 enters the clearance groove 43 while the remainder remains in the inner region of the inner peripheral frame 511, as shown in FIG. 11C, for example.

Note that, although an example in which the mounting substrate 3 is heated before the micro-vibrator 2 is fitted into the inner frame 511 has been described here, this is not limiting, and the mounting substrate 3 may be heated after the micro-vibrator 2 is fitted into the inner frame 511.

Then, as shown in FIG. 11D, for example, the pickup mechanism 300 is used to hold the suction surface 22a of the micro-vibrator 2 by vacuum suction, while fitting the micro-vibrator 2 into the annular inner frame 511 of the mounting substrate 3 and inserting it into the inner region. This allows the micro-vibrator 2 to be positioned easily and with high precision relative to the mounting substrate 3, and has the effect of suppressing subsequent positional deviation of the micro-vibrator 2 in the in-plane direction, i.e., on the xy plane. Next, 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 performed, 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.

As described above, the inner diameter of the inner frame 511 is set to a dimension that creates a predetermined clearance with respect to the outer diameter of the recess 22 of the micro-vibrator 2. Therefore, in addition to adjusting the relative positions of the micro-vibrator 2 and the mounting substrate 3 using image processing technology, by fitting the micro-vibrator 2 into the inner frame 511, it is possible to easily ensure the alignment accuracy of the micro-vibrator 2 with respect to the mounting substrate 3.

Then, the pickup mechanism 300 pushes the micro-vibrator 2 toward the mounting substrate 3, pressing the bonding material 52 that has melted on the mounting surface 22b. At this time, as shown in FIG. 11E, for example, the excess portion of the melted bonding material 52 is pushed out into the escape groove 43, and flows from the inner region to the outer region through the escape groove 43. As a result, no more bonding material 52 than necessary is interposed between the mounting surface 22b of the micro-vibrator 2 and the mounting surface of the lower substrate 4 that faces the mounting surface 22b, so that the distance between these surfaces is equal to or less than a predetermined value, and tilting of the micro-vibrator 2 with respect to the mounting substrate 3 can be suppressed.

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. 11F, 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.

Then, 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 board (not shown) or the like, wire bonding is performed on the electrode films 531, 541 of the mounting substrate 3, the circuit board or the like is electrically connected to the electrode portion 53 and the outer frame portion 54 of the mounting substrate 3, and a vacuum airtight seal is performed to manufacture the inertial sensor 1.

The above is the basic manufacturing method for the inertial sensor 1 of this embodiment.

[Mounting board clearance groove]
The effect of suppressing the inclination of the micro-vibrator 2 by the relief groove 43 will be described in comparison with the case where the micro-vibrator 2 is bonded to the mounting substrate 6 of the comparative example shown in FIG. 12A.

The mounting board 6 of the comparative example is formed by bonding an upper board 5 to a lower board 4, and a mounting section 61 consisting of a single annular frame is formed on the upper board 5. In the mounting board 6 of the comparative example, a bonding member 52 is disposed in an area surrounded by the mounting section 61, and the recess 22 of the micro-vibrator 2 is bonded via the bonding member 52. The inner diameter of the mounting section 61 is larger than the outer diameter of the recess 22 of the micro-vibrator 2, and when the micro-vibrator 2 is inserted, a clearance of, for example, several tens of μm is generated, and the mounting section 61 is sized not to come into contact with the micro-vibrator 2. Furthermore, the mounting board 6 of the comparative example does not have an escape groove 43 formed.

When the micro-vibrator 2 is bonded to the mounting substrate 6 of the comparative example, the micro-vibrator 2 may tilt relative to the mounting substrate 6, as shown in FIG. 12B, for example. This is because, in the mounting substrate 6 of the comparative example, all of the bonding member 52 remains within the annular mounting portion 61, resulting in more bonding member 52 than necessary being interposed between the lower substrate 4 and the micro-vibrator 2, and the distance between the mounting surface 22b of the micro-vibrator 2 and the mounting surface of the lower substrate 4 becoming larger. In this case, the micro-vibrator 2 may float on the bonding member 52 until the bonding member 52 solidifies, and may tilt relative to the mounting substrate 6 of the comparative example.

In contrast, the mounting substrate 3 according to this embodiment is configured such that an escape groove 43 is provided in the inner region of the mounting portion 51 of the lower substrate 4, and the excess portion of the molten bonding material 52 is guided to the outer region. As a result, when bonding the micro-vibrator 2, the presence of more bonding material 52 than necessary between the mounting surface 22b of the micro-vibrator 2 and the mounting surface of the lower substrate 4 is suppressed, and the distance between these surfaces is reduced. Therefore, the micro-vibrator 2 is suppressed from swimming on the bonding material 52, i.e., tilting with respect to the mounting substrate 3, until the molten bonding material 52 solidifies again.

[Holding of micro-vibration body, inner frame of mounting board]
The method of holding the micro-vibrator 2 and the effect of the inner peripheral frame 511 of the mounting substrate 3 in the above manufacturing method will be described.

When manufacturing an inertial sensor 1 with a BRG structure, it is necessary to make the distance between the rim 211 of the micro-vibrator 2 and each of the multiple electrode parts 53 the same, and to make the initial capacitance of the capacitor formed by one electrode part 53 and the opposing micro-vibrator 2 constant. This is because if the gap between the micro-vibrator 2 differs for each electrode part 53, the change in capacitance of the capacitor associated with the displacement of the micro-vibrator 2 when an external force is applied to the inertial sensor 1 will differ for each electrode part 53, and the sensor accuracy will decrease. Therefore, when mounting the micro-vibrator 2 on the mounting substrate 3, a certain level of high accuracy is required for its positioning.

One example of positioning mounting that requires high accuracy is a method that uses image processing to detect edges and extract feature points of each component. Specifically, after capturing an image of the micro-vibrator 2 and mounting board 3, known image processing is used to detect the edges of the micro-vibrator 2 and mounting board 3, extract feature points, estimate their positional relationship, and align the micro-vibrator 2 onto the mounting board 3.

However, when the curved surface 21 or rim 211 of the three-dimensionally curved micro-vibrator 2 is gripped, part of the micro-vibrator 2 is hidden by the gripping mechanism, making it difficult to extract the feature points of the micro-vibrator 2 by edge detection. Therefore, a mounting method for the micro-vibrator 2 that uses only image processing is complicated, and there is a risk that the micro-vibrator 2 or its electrode film may be damaged due to misalignment, and manufacturing costs may increase.

The inventors therefore devised a method of inserting a collet 302 into the recess 22 of the micro-vibrator 2 and gripping the micro-vibrator 2 by vacuum suction to the suction surface 22a. This reduces the area where the outer contour of the micro-vibrator 2 is hidden by the gripping mechanism, making it easier to extract feature points of the micro-vibrator 2 in image processing, and also suppressing damage to the micro-vibrator 2.

The inventors have also devised a method in which the mounting section 51 of the mounting substrate 3 is composed of an annular inner frame 511 and an outer frame 512 surrounding it, the inner diameter of the inner frame 511 corresponds to the outer diameter of the recess 22 of the micro-vibrator 2, and the micro-vibrator 2 is fitted into the inner frame 511. According to this, if the relative positions of the micro-vibrator 2 and the mounting substrate 3 are roughly adjusted by image processing, it becomes easy to fit the micro-vibrator 2 into the inner frame 511 of the mounting substrate 3. Furthermore, since the micro-vibrator 2 is aligned with the mounting substrate 3 by fitting it into the inner frame 511, it becomes possible to easily position it with a predetermined degree of accuracy or higher.

According to this embodiment, the inertial sensor 1 has a structure in which the micro-vibrator 2 is mounted on the mounting substrate 3 having a mounting section 51 composed of an inner peripheral frame 511 and an outer peripheral frame 512, with the inner and outer regions connected by an escape groove 43. Since the micro-vibrator 2 is fitted into the inner peripheral frame 511, positioning of the micro-vibrator 2 is simple and highly accurate, and the escape groove 43 of the mounting substrate 3 suppresses tilt of the micro-vibrator 2, resulting in a highly reliable and sensitive inertial sensor 1.

Second Embodiment
The inertial sensor 1 of the second embodiment will be described with reference to FIGS.

The inertial sensor 1 of this embodiment differs from the first embodiment in that the mounting substrate 3 has an upper end groove 55 formed at the upper end of the inner peripheral frame 511 instead of the escape groove 43, as shown in FIG. 13, for example. This difference will be mainly described in this embodiment.

In the present embodiment, as shown in FIG. 14, for example, the mounting substrate 3 has an upper end groove 55 formed in the upper surface 511a of the inner frame 511, which allows the excess portion of the joining member 52 to escape from the inner region to the outer region. Note that the upper surface 511a of the inner frame 511 is the surface opposite the lower surface 511b, with the surface of the inner frame 511 facing the lower substrate 4 being the lower surface 511b, as shown in FIG. 15, and is located at the upper end of the inner frame 511. For example, the mounting substrate 3 has a configuration in which the inner frame 511 has multiple upper end grooves 55, and the multiple upper end grooves 55 are arranged symmetrically when viewed from above.

The upper end groove 55 is formed in a process of separating the upper substrate 5 into the inner peripheral frame 511, the outer peripheral frame 512, the electrode portion 53, and the outer frame portion 54 by trench etching such as DRIE. Specifically, for example, in trench etching of the upper substrate 5, a mask is used that covers the region corresponding to the upper end groove 55 while exposing the region to be separated in the upper substrate 5 at the beginning of etching. Then, during the etching, a different mask is used that exposes the region to be separated in the upper substrate 5 and the region corresponding to the upper end groove 55, and etching is performed until a part of the lower substrate 4 is exposed from the upper substrate 5. The upper end groove 55 is formed, for example, by the process described above, but may be formed by performing etching in a process other than the separation process of the upper substrate 5. The number, arrangement, dimensions, etc. of the upper end grooves 55 can be changed as appropriate. The upper end groove 55 corresponds to the escape groove 43 in the first embodiment described above, and plays a similar role to the escape groove 43.

The inner peripheral frame 511 has a smaller height than the outer peripheral frame 512 in the portion where the upper end groove 55 is formed, as shown in FIG. 14, for example, and the other portions have the same height as the outer peripheral frame 512, as shown in FIG. 15, for example.

The inertial sensor 1 of this embodiment is manufactured by the same process as the first embodiment, except that a mounting substrate 3 having an upper end groove 55 of an inner peripheral frame 511 is prepared instead of the escape groove 43 of the lower substrate 4. When the micro-vibrator 2 is bonded to this mounting substrate 3, the excess part of the bonding member 52 creeps up to the upper side of the mounting substrate 3 and is pushed out to the height of the upper end groove 55, as shown in FIG. 16, for example, and flows from the inner region to the outer region through the upper end groove 55. This prevents the bonding member 52 from being interposed more than necessary between the mounting surface 22b of the micro-vibrator 2 and the mounting surface of the mounting substrate 3, and reduces the distance between these surfaces. As a result, the micro-vibrator 2 is prevented from tilting with respect to the mounting substrate 3, and a highly reliable and sensitive inertial sensor 1 can be manufactured.

According to this embodiment, the inertial sensor 1 uses a mounting substrate 3 configured such that the upper end groove 55 provided in the inner peripheral frame 511 functions as an escape groove for allowing the excess portion of the joining member 52 to escape from the inner region to the outer region. As a result, similar to the first embodiment, it is possible to achieve both easy positioning of the micro-vibrator 2 relative to the mounting substrate 3 and suppression of tilt, resulting in a highly reliable and sensitive inertial sensor 1.

Third Embodiment
The inertial sensor 1 of the third embodiment will be described with reference to FIGS.

In FIG. 17, in order to make the configuration of the inner peripheral frame 511 easier to understand, the outer contour of another cross section of the inner peripheral frame 511 adjacent to the lower end groove 56 described below is shown by a dashed line.

The inertial sensor 1 of this embodiment differs from the first embodiment in that the mounting substrate 3 has a bottom groove 56 formed at the bottom end of the inner frame 511 instead of the escape groove 43, as shown in, for example, Figures 17 and 18. This difference will be mainly described in this embodiment.

In this embodiment, as shown in FIG. 18, the mounting substrate 3 has an inner peripheral frame 511 with multiple bottom end grooves 56, and no escape grooves 43 are formed in the lower substrate 4.

As shown in FIG. 18, the lower end groove 56 is a through hole that is provided on the lower end side of the inner frame 511 in a planar direction, i.e., in a direction belonging to the xy plane, and communicates between the inner region and the outer region of the lower substrate 4. In this embodiment, the lower end groove 56 is a groove through which the excess part of the joining member 52 is pushed out when the micro-vibration body 2 is joined, similar to the escape groove 43 in the first embodiment, and plays a role in letting the excess part escape from the inner region to the outer region. The lower end groove 56 is formed, for example, by forming a groove by DRIE on the joining surface of the Si substrate that will later become the upper substrate 5 with the lower substrate 4, and then, after the lower substrate 4 is joined to the Si substrate, the groove is connected to the side of the inner frame 511 in the process of forming the inner frame 511. The number, arrangement, dimensions, etc. of the lower end grooves 56 are not limited to the example shown in the figure, and can be changed as appropriate.

In other words, as shown in FIG. 19, for example, when the micro-vibrator 2 is bonded to the mounting substrate 3, the excess portion of the bonding material 52 flows from the inner region to the outer region through the lower end groove 56, reducing the gap between the mounting surface 22b of the micro-vibrator 2 and the mounting surface of the lower substrate 4. The inertial sensor 1 using this mounting substrate 3 has a structure in which the micro-vibrator 2 is easily and highly accurately positioned by being fitted into the inner peripheral frame 511, while the tilt of the micro-vibrator 2 is suppressed.

According to this embodiment, the inertial sensor 1 uses a mounting substrate 3 configured such that, when the micro-vibrator 2 is mounted, the bottom end groove 56 provided in the inner peripheral frame 511 allows the excess portion of the bonding member 52 to escape from the inner region to the outer region. As a result, similar to the first embodiment, the micro-vibrator 2 can be easily and highly accurately positioned relative to the mounting substrate 3, and tilting of the micro-vibrator 2 is suppressed, resulting in a highly reliable and sensitive inertial sensor 1.

(Modification of the third embodiment)
The mounting substrate 3 may have an inner peripheral frame 511 having a bottom end groove 56 as well as a plurality of side grooves 57 communicating with the bottom end groove 56, as shown in, for example, FIGS.

The side grooves 57 are bottomed grooves that are provided in the height direction connecting the upper surface 511a and the lower surface 511b of the inner frame 511, that is, along the z direction shown in FIG. 21. The side grooves 57 are provided in the inner frame 511 in the same number as the bottom end grooves 56, for example, and extend so that one end is connected to the opening of the bottom end groove 56 on the outer frame 512 side. As shown in FIG. 22, for example, when the micro-vibrator 2 is bonded to the mounting substrate 3, the side grooves 57 guide a part of the excess part of the bonding member 52 that flows out to the outer area through the bottom end groove 56 to the upper end side of the inner frame 511. In other words, the side grooves 57 are formed to prevent the excess part of the bonding member 52 from flowing out to an unintended area.

The side grooves 57 are formed, for example, during an etching process in which the Si substrate (later upper substrate 5) and the lower substrate 4 are bonded together and then the Si substrate is separated by DRIE into the inner peripheral frame 511, the outer peripheral frame 512, the electrode portion 53, and the outer frame portion 54. As shown in FIG. 20, for example, the side grooves 57 are substantially U-shaped when viewed from above, but may be substantially V-shaped or have any other shape as long as they can guide the excess portion of the molten bonding material 52 that has flowed out from the lower end groove 56 to the outer region. The number and arrangement of the side grooves 57 can be changed as appropriate depending on the number and arrangement of the lower end grooves 56.

In addition, by providing the mounting substrate 3 with the side grooves 57 on the inner peripheral frame 511, as shown in FIG. 22, for example, the excess portion of the joining member 52 that flows out from the inner region to the outer region is prevented from reaching the outer peripheral frame 512. Therefore, when the mounting substrate 3 is provided with the side grooves 57, the outer peripheral frame 512 may be formed into a frame shape with a gap when viewed from above.

This modified example also provides an inertial sensor 1 that can achieve the same effect as the third embodiment. In addition, the side groove 57 that communicates with the lower end groove 56 guides the excess portion of the joining member 52 to the upper end of the inner peripheral frame 511, which also has the effect of preventing the joining member 52 from flowing out into unintended areas.

Fourth Embodiment
The inertial sensor 1 of the fourth embodiment will be described with reference to FIGS.

The inertial sensor 1 of this embodiment differs from the first embodiment in that the escape groove 43 of the mounting substrate 3 is an inner groove formed only in the inner region of the inner peripheral frame 511, as shown in FIG. 23 for example. This difference will be mainly described in this embodiment.

In this embodiment, the escape groove 43 of the mounting substrate 3 is an inner groove provided only in the inner region, as shown in FIG. 24, for example. In this embodiment, as shown in FIG. 25, for example, when the micro-vibrator 2 is bonded, the escape groove 43 allows the excess part of the bonding material 52 to escape downward in the z direction instead of to the outer region, thereby suppressing the inclination of the micro-vibrator 2. The escape groove 43 also functions as a groove that clarifies the part that contributes to the bonding with the micro-vibrator 2 in the inner region of the lower substrate 4, that is, the mounting part, and also plays a role in stabilizing the bonding between the micro-vibrator 2 and the mounting part. Note that the mounting part here is the region surrounded by the annular escape groove 43 in the inner region of the lower substrate 4 in the example shown in FIG. 23, but is not limited to this example.

The escape groove 43 is, for example, annular when viewed from above, but the shape, number, arrangement, etc. can be changed as appropriate as long as it can allow the excess portion of the joining member 52 to escape while securing the joining area between the micro-vibration body 2 and the lower substrate 4. For example, the escape groove 43 may be a frame-shaped groove other than annular when viewed from above, and the shape can be changed as appropriate depending on the shape of the inner frame 511, etc.

According to this embodiment, too, an inertial sensor 1 that can obtain the same effects as those of the first embodiment can be obtained.
Fifth Embodiment
The inertial sensor 1 of the fifth embodiment will be described with reference to FIGS.

As shown in FIG. 26, the inertial sensor 1 of this embodiment differs from the first embodiment in that the escape groove 43 of the mounting substrate 3 is made up of an annular inner groove 431 provided in the inner region and a plurality of communicating grooves 432 extending from the inner groove 431 toward the outer region. This embodiment will mainly describe this difference.

In this embodiment, the mounting substrate 3 has an escape groove 43 formed in the lower substrate 4. The escape groove 43 is composed of an annular inner groove 431 provided only in the inner region, and multiple communication grooves 432, one end of which is connected to the inner groove 431 and the other end of which is connected to the outer region.

In this embodiment, the inner groove 431 is a groove formed only in the inner region, as shown in FIG. 27, for example. When viewed from above, the inner groove 431 is, for example, a ring-shaped groove connecting multiple communicating grooves 432. The inner groove 431 functions as a groove for allowing some of the excess part of the molten joining material 52 to escape when joining the micro-vibration body 2, and also plays a role in clarifying the mounting part in the inner region.

The multiple communication grooves 432 are arranged symmetrically in a top view, as shown in FIG. 26, for example. The communication grooves 432 communicate the inner region and the outer region in the lower substrate 4, as shown in FIG. 28, for example, and play a role in allowing excess portions of the molten bonding material 52 to escape from the inner region to the outer region when bonding the micro-vibration body 2. The number and arrangement of the communication grooves 432 are not limited to the example shown in FIG. 26, and can be changed as appropriate.

According to this embodiment, the inertial sensor 1 is configured such that the excess portion of the joining material 52 at the time of joining the micro-vibrator 2 escapes into the outer region and the inner groove 431 by the escape groove 43 provided in the lower substrate 4 of the mounting substrate 3. Therefore, the same effects as those of the first and fourth embodiments can be obtained.

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.

For example, the mounting substrate 3 may be configured to include the escape groove 43 of the first embodiment and the side groove 57 of the third embodiment. In this case, the mounting substrate 3 may be configured, for example, to include a side groove 57 in a portion of the wall surface on the outer region side of the inner periphery frame 511 that is positioned above the escape groove 43 of the lower substrate 4 when viewed from above. In this way, the mounting substrate 3 constituting the inertial sensor 1 may be configured to freely combine the components of each of the above embodiments to the extent possible.

1: inertial sensor, 2: micro-vibrator, 21: curved surface portion, 22: recessed portion,
3: mounting substrate, 4: lower substrate, 43: relief groove, 5: upper substrate,
511...Inner circumference frame, 511a...Top surface, 511b...Bottom surface, 512...Outer circumference frame,
52: Joint member, 53: Electrode portion, 55: Upper end groove, 56: Lower end groove,
57...Side groove

Claims (10)

An inertial sensor,
A micro-vibration body (2) having a curved surface portion (21) having an annular curved surface and a recessed portion (22) recessed from the curved surface portion;
a mounting substrate (3) formed by bonding an upper substrate (5) to a lower substrate (4); the upper substrate (5) has an inner frame (511) in the shape of a frame body into which the recess of the micro-vibrator is fitted, an outer frame (512) in the shape of a frame body surrounding the inner frame, and a plurality of electrode portions (53) arranged to surround the outer frame while being spaced apart from each other;
a joining member (52) at least a portion of which is disposed inside the inner peripheral frame and which joins the micro-vibrator and the mounting substrate;
The micro-vibrator has a hollow curved surface,
The mounting substrate has an escape groove (43, 55, 56) provided in at least one of the inner region of the lower substrate and the inner frame, into which an excess portion of the joining member arranged inside the inner frame flows. The inertial sensor according to claim 1, wherein the clearance groove connects the area surrounded by the inner peripheral frame with the area between the outer peripheral frame and the inner peripheral frame. The inertial sensor according to claim 1 or 2, wherein the escape groove is part of the lower substrate and is arranged to straddle the inner peripheral frame. The inertial sensor according to claim 1 or 2, wherein the escape groove is provided in the inner peripheral frame. The inertial sensor according to claim 4, wherein the escape groove is a lower end groove (56) provided on the lower surface (511b) of the inner peripheral frame that faces the lower substrate. The inner peripheral frame has a side groove (57) provided along a direction connecting an upper surface (511a) opposite to the lower surface and the lower surface,
The inertial sensor according to claim 5 , wherein one end of the side groove is in communication with the lower end groove. The inertial sensor according to claim 4, wherein the escape groove is an upper end groove (55) provided on the upper surface (511a) of the inner peripheral frame opposite the lower surface (511b) facing the lower substrate. The inertial sensor according to any one of claims 1 to 7, wherein the inner frame is annular. A micro-vibration body (2) having a curved surface portion (21) having an annular curved surface and a recessed portion (22) recessed from the curved surface portion;
a mounting substrate (3) including a lower substrate (4), an upper substrate (5) having a frame-shaped inner peripheral frame (511) into which the recess of the micro-vibrator is fitted and joined to the lower substrate, and the recess of the micro-vibrator is joined to an inner region of the inner peripheral frame via a joining member (52);
A manufacturing method for an inertial sensor (1) in which the curved surface portion is in a hollow state when the micro-vibrator is mounted on the inner peripheral frame, comprising:
preparing the micro-vibrator;
providing the mounting substrate;
disposing the bonding member on the mounting substrate in an inner region of the inner peripheral frame;
After arranging the bonding member, the recess of the micro-vibration body is fitted into the inner region of the inner periphery frame to bring the bonding member into contact with the recess of the micro-vibration body;
and heating the mounting substrate to melt and solidify the bonding material, thereby bonding the micro-vibrator to the mounting substrate;
In preparing the mounting substrate, the mounting substrate is provided with a frame-shaped outer peripheral frame (512) surrounding the inner peripheral frame, a plurality of electrode portions (53) arranged to surround the outer peripheral frame while being spaced apart from each other, and a clearance groove (43, 55, 56) provided in at least the inner region of the inner peripheral frame or in the inner peripheral frame of the lower substrate;
In the method for manufacturing an inertial sensor, in bonding the micro-vibrator, the recess of the micro-vibrator is pressed against the lower substrate, and an excess portion of the molten bonding material is pushed out into the relief groove. The method for manufacturing an inertial sensor according to claim 9, wherein, in disposing the joining member, a plate-shaped member formed from a conductive material mainly composed of AuSn is disposed in the inner region.

Images