Micro-vibrating body, inertial sensor, method for manufacturing a micro-vibrating body, and method for manufacturing an inertial sensor

Abstract

To set the thickness of a surface electrode of a minute vibrating body that can be vibrated in a wine glass mode to a predetermined value or smaller, and ensure adhesiveness and conductivity.SOLUTION: A minute vibrating body 2 includes: a base section 20 having a curved surface section 21 having an annular curved surface and a connection section 22 in a bottomed cylindrical shape that is recessed from a surface 21a of the curved surface section to the center of a virtual hemisphere; and a surface electrode 23 for covering at least one portion of the surface of the base section. The surface electrode 23 is formed by the atomic layer deposition method, and covers the base section 20 composed of glass. The surface electrode 23 is an oxynitride film with Ti as a main constituent, and the ratio of Ti-O is within a range of 26-52 wt.%.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a micro-vibrator in which the surface of a glass structure having a three-dimensional curved surface shape is covered with a conductive film, an inertial sensor using the same, and manufacturing methods thereof.

Background Art

[0002] In recent years, the development of vehicle automatic driving systems has been underway. 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 situation 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 that vibrates in a wine glass mode is mounted on a mounting substrate. BRG is an abbreviation for Bird-bath Resonator Gyroscope. In order for this micro-vibrator to achieve a Q value representing the vibration state of 10 6 or more, higher sensitivity than before is expected.

[0004] For example, the micro-vibrator described in Patent Document 1 has a base made of glass, and its surface is covered with a surface electrode. This micro-vibrator has a structure in which the surface electrode covering the surface is made of a material such as Ti (titanium)-Pt (platinum) or Cr (chromium)-Au (gold), and is laminated in the order of an adhesion layer and a conductive layer from the base.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] U.S. Patent No. 10612925 [Overview of the project] [Problems that the invention aims to solve]

[0006] The micro-vibrating body described in Patent Document 1 requires the surface electrode to have a laminated structure consisting of an adhesion layer and a conductive layer, which increases the total thickness of the surface electrode and thus lowers the Q value of the vibration. Furthermore, if the total thickness of the surface electrode, especially the thickness of the adhesion layer, is reduced, thermal migration during the manufacturing process of the micro-vibrating body may cause insulation, or adhesion to the base may decrease, leading to peeling of the film or poor bonding with the mounting substrate.

[0007] In view of the above, the present invention aims to provide a micro-vibrating body and a method for manufacturing the same, which suppresses the thickness of the surface electrode to a predetermined level or less, suppresses the decrease in the Q value of vibration, ensures the conductivity and adhesion of the surface electrode, and suppresses bonding defects to the mounting substrate. Furthermore, the present invention aims to provide an inertial sensor using a micro-vibrating body that achieves both ensuring the conductivity and adhesion of the surface electrode and suppressing bonding defects to the mounting substrate, and a method for manufacturing the same. [Means for solving the problem]

[0008] To achieve the above objective, the micro-vibrator described in claim 1 is a micro-vibrator capable of vibrating in wine glass mode, comprising: a base (20) having a curved surface portion (21) having an annular curved surface; a bottomed cylindrical connecting portion (22) that is recessed from the surface (21a) of the curved surface portion toward the center of the virtual hemisphere formed by the curved surface portion; and a surface electrode (23) covering at least a part of the surface of the base portion, wherein the base portion is made of glass, and the surface electrode is formed by atomic layer deposition, with Ti as the main component. And, an acid to which oxygen has been added. It is a nitride film.

[0009] This results in a micro-vibrating body having a curved portion and a connecting portion, with a glass base on which a surface electrode made of a nitride mainly composed of Ti is formed by atomic layer deposition. And, an acid to which oxygen has been added. Composed of nitride and adhering to a glass base, it eliminates the need for a laminated structure of adhesion layer and conductive layer, ensuring adhesion and conductivity of the surface electrode while keeping the total thickness of the surface electrode below a predetermined level. Furthermore, because the adhesion and conductivity of the surface electrode are ensured, poor bonding to the mounting substrate are suppressed.

[0010] Claim 3 The method for manufacturing a micro-vibrating body described herein is a method for manufacturing a micro-vibrating body capable of vibrating in wine glass mode, and includes: preparing a base (20) made of glass having a curved surface portion (21) having an annular curved surface and a bottomed cylindrical connecting portion (22) that is recessed from the surface (21a) of the curved surface portion toward the center of the virtual hemisphere formed by the curved surface portion; preparing a jig (J) having a support portion (J1) that is inserted into the connecting portion and capable of supporting the base; and forming a surface electrode (23) that covers the surface by atomic layer deposition while the support portion is inserted into the connecting portion and the base portion is held in the jig. When preparing the jig, prepare one in which the end surface of the support part is not chamfered. In forming the surface electrode, the base is held in a state where it does not come into contact with a part of the jig other than the support part, and a nitride film mainly composed of Ti is deposited.

[0011] This provides a method for manufacturing a micro-vibrator, which involves preparing a base made of glass having a curved portion and a connecting portion, setting the base in a jig having a support portion, and forming a surface electrode by depositing a nitride film mainly composed of Ti using atomic layer deposition. By depositing a nitride film mainly composed of Ti on glass, it is possible to ensure adhesion and conductivity of the surface electrode while keeping the total thickness of the surface electrode below a predetermined level, thereby manufacturing a micro-vibrator with suppressed bonding defects with the mounting substrate.

[0012] Claim 5The inertial sensor described herein comprises a base (20) having a curved surface portion (21) having an annular curved surface, a bottomed cylindrical connecting portion (22) recessed from the surface (21a) of the curved surface portion toward the center of the virtual hemisphere formed by the curved surface portion, and a surface electrode (23) covering at least a part of the surface of the base portion, and a micro-vibrating body (2) in which the curved surface portion can vibrate in wine glass mode, and a mounting substrate (3) to which the connecting portion is joined, having a plurality of electrode portions (53) arranged to surround the rim (211) of the curved surface portion opposite to the connecting portion, separated from each other, and the base portion is made of glass, and the surface electrode is formed by atomic layer deposition, with Ti as the main component. And, an acid to which oxygen has been added. It is a nitride film.

[0013] As a result, the micro-vibrator described in claim 1 is bonded to the mounting substrate, the total thickness of the surface electrodes of the micro-vibrator is kept below a predetermined level, the decrease in the Q value of the vibration is suppressed, while the adhesion and conductivity of the surface electrodes are ensured, resulting in an inertial sensor in which bonding defects with the mounting substrate are suppressed.

[0014] Claim 6 The method for manufacturing an inertial sensor described herein is a method for manufacturing an inertial sensor in which a micro-vibrating body (2) capable of vibrating in wine glass mode is bonded to a mounting substrate (3), and includes preparing a base (20) made of glass having a curved surface portion (21) having an annular curved surface and a bottomed cylindrical connecting portion (22) that is recessed from the surface (21a) of the curved surface portion toward the center of the virtual hemisphere formed by the curved surface portion; preparing a jig (J) having a support portion (J1) that is inserted into the connecting portion and capable of supporting the base; forming a micro-vibrating body by depositing a surface electrode (23) covering the surface by atomic layer deposition while the support portion is inserted into the connecting portion and the base portion is held in the jig; and preparing a mounting substrate and bonding the connecting portion of the micro-vibrating body to the mounting substrate, wherein in depositing the surface electrode, Ti is the main component. And, an acid to which oxygen has been added. A nitride film is deposited.

[0015] This makes the claim 3A method for manufacturing an inertial sensor is provided, which includes using a micro-vibrator manufactured by the method described in and bonding the micro-vibrator to a mounting substrate. Since the total thickness of the surface electrodes of the micro-vibrator is set to be a predetermined value or less, it is possible to manufacture an inertial sensor in which the decrease in the Q value of vibration is suppressed, the adhesion and conductivity of the surface electrodes are ensured, and the bonding failure with the mounting substrate is suppressed.

[0016] Note that the reference numerals in parentheses attached to each component etc. indicate an example of the correspondence relationship between the component etc. and the specific components etc. described in the embodiments described later.

Brief Description of the Drawings

[0017] [Figure 1] FIG. is a perspective view showing an example of an inertial sensor using a micro-vibrator according to an embodiment. [Figure 2] FIG. is a cross-sectional view of a micro-vibrator according to an embodiment. [Figure 3] FIG. is a cross-sectional view taken between III-III of FIG. 1. [Figure 4] FIG. shows the relationship between the Ti-O ratio in the titanium oxynitride film, the bonding strength, and the resistance value. [Figure 5] FIG. is an explanatory view of a jig used in the film formation process of the surface electrodes of the micro-vibrator. [Figure 6] FIG. is a perspective view showing the tip surface of the jig of FIG. 5.

Modes for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described based on the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals for explanation.

[0019] (First Embodiment) The inertial sensor 1 of the first embodiment will be described with reference to the drawings.

[0020] In Figure 1, to make the configuration of the inertial sensor 1 easier to understand, the lower substrate 4, upper substrate 5, and a portion of the micro-vibrating body 2, which will be described later, are omitted, while a partial cross-sectional view of the micro-vibrating body 2 is shown. In Figure 3, to make the configuration of the inertial sensor 1 easier to understand, the outer edges of the electrode portion 53 and electrode film 531, which will be described later and are located in a different cross-section, are shown with dashed lines.

[0021] For the sake of explanation, as shown in Figure 1, one direction in the planar direction of the mounting substrate 3 will be referred to as the "x direction," the direction perpendicular to the x direction on the same plane will be referred to as the "y direction," and the direction normal to the xy plane will be referred to as the "z direction." The x, y, and z directions in Figures 2 and onward correspond to the x, y, and z directions in Figure 1, respectively. Furthermore, in this specification, "up" refers to the direction along the z direction in the figures, meaning the side indicated by the arrow, and "down" refers to the opposite side of "up." In addition, in this specification, the view of the inertial sensor 1, micro-vibrator 2, or mounting substrate 3 from the upper side in the z direction will sometimes be referred to as a "top view."

[0022] The micro-vibrating body 2 according to this embodiment is preferably mounted on a substrate 3, as shown in Figure 1, and used to constitute an inertial sensor such as a gyro sensor, like a BRG, but it can also be used for other applications such as a clock device. In this specification, the case in which it is used as a component of a BRG is described as a representative example, but it is not limited to this application.

[0023] [Inertial sensor] An example of an inertial sensor 1 having a micro-vibrating body 2 will be described. As shown in Figure 1, for example, the inertial sensor 1 comprises a micro-vibrating body 2 and a mounting substrate 3, with a part of the micro-vibrating body 2 being bonded 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-walled micro-vibrating body 2, which is capable of vibrating in wineglass mode, and a plurality of electrode portions 53 of the mounting substrate 3.

[0024] The micro-vibrating body 2, as shown in Figure 2 for example, has a base portion 20 covered with surface electrodes 23, which includes a curved surface portion 21 that includes the outer shape of a roughly hemispherical three-dimensional curved surface, and a connecting portion 22 that extends from the apex side of the virtual hemisphere formed by the curved surface portion 21 toward the center side of the hemisphere. The connecting portion 22 is a connection part that connects to other members such as a mounting substrate 3, and is, for example, a bottomed cylindrical recess. The micro-vibrating body 2, for example, has a curved surface portion 21 that has a bowl-shaped three-dimensional curved surface, and its vibration Q value is 10 5 That's all.

[0025] The base portion 20 is made of a reflow material consisting of glass containing additives such as quartz glass, borosilicate glass, metallic glass, or silicon. The base portion 20 is not limited to the aforementioned material examples, as long as it is made of glass that can form a three-dimensional curved surface portion 21 and a connecting portion 22 and can vibrate in wine glass mode. The base portion 20 is formed, for example, by processing a thin substrate made of the above material through a forming process described later, so that the thickness of the curved surface portion 21 and the connecting portion 22 is on the order of micrometers, such as 10 μm to 100 μm. The base portion 20 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.

[0026] The base 20 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 in the center of the recess that supports a part of the quartz plate 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 sealing material made of any curable resin material. After that, for example, unnecessary parts of the processed quartz plate are removed by polishing and CMP along with the sealing material, and then all the sealing material 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 portion 20 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 portion 20 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.

[0027] 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 such that the front surface 2a side faces the multiple electrode portions 53 on the mounting substrate 3, and the distance between the multiple electrode portions 53 is 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 mounted on the substrate 3, the micro-vibrator 2 has a structure in which the hollow rim 211 can vibrate in wineglass mode.

[0028] The micro-vibrating body 2 has a surface electrode 23 that covers part or all of the surface 21a and back surface 21b of the base portion 20, as shown in Figures 2 and 3, for example. Surface 21a is the side of the curved portion 21 with the larger outer diameter, and back surface 21b is the opposite side. The micro-vibrating body 2 has a mounting surface 22b on the back surface 21b side of the connection portion 22 that faces the mounting substrate 3. The micro-vibrating body 2 has a bottom surface of the connection portion 22 that is opposite to the mounting surface 22b, i.e., the bottom surface 22a of the recess, which can be used as a support surface by the jig J described later when forming the surface electrode 23, and can also be used as an adsorption surface for adsorption and transport of the micro-vibrating body 2.

[0029] The surface electrode 23 is composed of a nitride film mainly composed of Ti (titanium). Specifically, the surface electrode 23 is a film of TiN (titanium nitride) with added O (oxygen), i.e., a titanium oxynitride film, with the Ti-O ratio in the entire film being in the range of 26 to 52 wt%. The surface electrode 23 is deposited on the surface 21a and back surface 21b of the base 20 by atomic layer deposition (ALD) with a thickness of, for example, in the range of 3 to 15 nm. The surface electrode 23 is deposited on, for example, at least the mounting surface 22b and the surface 21a of the rim 211, and these parts are electrically connected. The surface electrode 23 may be in a solid shape that covers the entire front and back surfaces of the micro-vibrator 2, but it may also be in a pattern shape that covers only a predetermined area. The surface electrode 23 is connected to the mounting substrate 3 via a bonding member 52 made of a conductive material such as AuSn (gold-tin), for example, a predetermined area including at least the portion covering the mounting surface 22b of the connection part 22.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] The inner frame portion 51 is formed together with multiple electrode portions 53 and an outer frame portion 54 by performing dry etching such as DRIE on the upper substrate 5 which is anodic-bonded to the lower substrate 4. 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 or fitted into the enclosed area. For example, after placing a 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.

[0034] 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 multiple electrode portions 53 can be controlled in potential 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. 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, or generate an electrostatic attraction between itself and the micro-vibrator 2, causing the micro-vibrator 2 to vibrate in a wine glass mode. To put it another way, some of the multiple electrode portions 53 are detection electrodes for detecting capacitance, and the remainder are drive electrodes for driving the micro-vibrator 2.

[0035] 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.

[0036] 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), then adsorbing and transporting the micro-vibrating body 2 with a transport device (not shown), and then heat bonding them. Alignment between 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 surface portion 21 by edge detection using known image recognition technology, and adjusting the relative position based on these feature points.

[0037] 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.

[0038] [Surface electrode] Next, the surface electrode 23 of the micro-vibrating body 2 and the method for depositing the film thereon will be described.

[0039] The surface electrode 23 is composed of an oxygen-doped TiN film and is a single layer that serves as both an adhesion layer and a conductive layer. To achieve both adhesion to the glass base 20 and the necessary conductivity as an electrode, the Ti-O ratio of the surface electrode 23 is within the range of 26-52 wt%. Through diligent research by the inventors, it was found that, as shown in Figure 4, the bonding strength and resistance of the oxygen-doped TiN film with the base 20 change depending on the Ti-O ratio. The Ti-O ratio was obtained by measurement using X-ray photoelectron spectroscopy (XPS) analysis.

[0040] For example, when the Ti-O ratios were 40.6 wt%, 43.2 wt%, and 63.5 wt%, the bonding strength with the base 20 was 3.8 MPa, 4.5 MPa, and 6.0 MPa, respectively. The bonding strength can be evaluated by, for example, preparing a sample by depositing a titanium oxynitride film with a thickness of approximately 3 to 15 nm onto a glass plate material (e.g., a quartz glass plate) that constitutes the base 20, and then performing a tensile test on the sample. Here, from the viewpoint of ensuring adhesion between the base 20 and the surface electrode 23, a bonding strength of 1 MPa or more is desirable. An approximate straight line was obtained using the least squares method based on the three data points for Ti-O ratios of 40.6 wt%, 43.2 wt%, and 63.5 wt%, and when this approximate straight line was extrapolated to the region with a lower Ti-O ratio, the bonding strength was 1 MPa when the Ti-O ratio was 26 wt%. In other words, by making the surface electrode 23 titanium oxynitride with a Ti-O ratio of 26 wt% or more, adhesion with the glass base 20 can be ensured, and bonding defects with the mounting substrate 3 are suppressed.

[0041] Furthermore, when the Ti-O ratios were 40.2 wt%, 52.0 wt%, and 97.6 wt%, the resistance values ​​were 150 Ω / □, 950 Ω / □, and 1.02 MΩ / □, respectively, as shown in Figure 4. The resistance value can be evaluated, for example, by preparing a sample with the same configuration as the bond strength evaluation sample and measuring it using the four-terminal method. Here, from the viewpoint of ensuring conductivity, it is desirable that the surface electrode 23 be at least 1 kΩ / □ or less. For this reason, conductivity is ensured by using titanium oxynitride with a Ti-O ratio of 52 wt% or less for the surface electrode 23.

[0042] Therefore, the surface electrode 23 is made of a single titanium oxynitride film with a Ti-O ratio in the range of 26 to 52 wt%, thereby achieving both adhesion to the base 20 and conductivity without the need for a laminated structure of an adhesion layer and a conductive layer. As a result, the micro-vibrating body 2 has a structure in which the Q value of vibration is suppressed by keeping the film thickness of the surface electrode 23 below a predetermined level, while ensuring adhesion and conductivity between the base 20 and the surface electrode 23, thereby suppressing bonding defects with the mounting substrate 3.

[0043] The surface electrode 23 is deposited by ALD using, for example, a jig J shown in Figure 5. The jig J has a columnar support portion J1 that is inserted into the connecting portion 22 of the base portion 20 and supports the base portion 20 by contacting the bottom surface 22a of the recess. The jig J has, for example, a plurality of support portions J1 arranged at predetermined intervals, and is configured to hold a plurality of base portions 20 without them contacting each other. The diameter of the connecting portion 22 on the side of the bottom surface 22a of the recess is taken as the inner diameter of the support portion J1, and the height of the support portion J1 is such that when the base portion 20 is set, the base portion 20 does not come into contact with any part other than the support portion J1. For example, the height of the support portion J1 is such that the distance H between the set base portion 20 and the surface of the jig J on which the support portion J1 is provided is 0.5 mm or more. This ensures sufficient space during film formation of the surface electrode 23 by ALD, allowing the material gas to flow into the recess bottom surface 22a side of the base 20, thereby suppressing uneven film formation on the surface electrode 23.

[0044] Furthermore, the support portion J1 is configured such that, as shown in Figure 6, for example, the surface that contacts the bottom surface 22a of the recess is the tip surface J1a, and the outer edge of the tip surface J1a is, for example, a roughly right-angle corner, i.e., it is not chamfered. This stabilizes the contact between the support portion J1 and the bottom surface 22a of the recess, suppresses tilting of the base portion 20 during film formation of the surface electrode 23, and stabilizes the film formation process. Note that in Figure 6, the support portion J1 is shown as a cylindrical shape with an unchamfered tip surface J1a, but it is not limited to this, and may be other columnar shapes such as a polygonal prism.

[0045] The jig J is coated with an oxide (not shown) on its surface, which suppresses outgassing from the jig during the ALD process and stabilizes the film deposition process. Examples of oxides not shown include aluminum oxide (Al x O y Examples include (where x and y are arbitrary numbers), but any material that has a high barrier property, i.e., one with a permeability of outgassing such as water and oxygen below a predetermined level, is acceptable, and any other material may be used.

[0046] Multiple bases 20 are set in the jig J described above, and a surface electrode 23 is formed by ALD. In the ALD process for forming the surface electrode 23, for example, TiCl4 gas is used as the raw material gas, NH3 gas is used as the nitriding gas, and N2 gas is used as the purge gas and carrier gas. For example, the jig J supporting multiple bases 20 is set in the chamber of an ALD deposition apparatus (not shown), and the vacuum level is set to 1.3 to 1.3 × 10⁻⁶. 3 The temperature during film formation is set to 300-500°C. For example, TiCl4 gas is supplied at a flow rate of 200-300 sccm, then N2 gas is supplied at a flow rate of 1500-2500 sccm to remove any residual TiCl4 gas, and then NH3 gas is supplied at a flow rate of 5500-6000 sccm. This cycle from supplying TiCl4 gas to supplying NH3 gas is repeated multiple times. Alternatively, for example, by supplying a small amount of O2 gas when supplying N2 gas or NH3 gas in the above film formation cycle, or by performing an oxidation treatment with O3 gas after forming the titanium nitride film in the film formation cycle, a titanium oxynitride film of a predetermined thickness can be obtained. This makes it possible to form a surface electrode 23 composed of a titanium oxynitride film with a Ti-O ratio in the range of 26-52 wt% on the front and back surfaces of the base 20, and obtain the above-described micro-vibrating body 2.

[0047] According to this embodiment, the micro-vibrating body 2 is formed by covering a base portion 20, which is made of glass and has a curved portion 21 and a connecting portion 22, with a surface electrode 23 made of an oxynitride film mainly composed of Ti and having a Ti-O ratio within a predetermined range. As a result, the micro-vibrating body 2 has a surface electrode 23 that is composed of a single layer of oxynitride film instead of a laminated structure of an adhesion layer and a conductive layer. Therefore, the total thickness of the surface electrode 23 is kept below a predetermined level, and adhesion and conductivity are ensured by having a Ti-O ratio within the range of 26 to 52 wt%. Thus, the decrease in the Q value of vibration is suppressed while achieving both adhesion and conductivity between the base portion 20 and the surface electrode 23, resulting in a micro-vibrating body 2 with suppressed bonding defects to the mounting substrate 3. Furthermore, the inertial sensor 1 using this micro-vibrating body 2 has a configuration that is highly sensitive due to the secured Q value of vibration and has improved reliability due to the suppression of bonding defects.

[0048] Furthermore, by using a jig J having a columnar support part J1 that supports the base 20 having a curved surface part 21 and a connecting part 22, a surface electrode 23 that achieves both adhesion to the base 20 and conductivity can be formed by ALD film deposition, thereby manufacturing a micro-vibrating body 2. In addition, by using a jig J in which the tip surface J1a of the support part J1 is not chamfered and the surface is covered with oxide, the base 20 is stabilized during film deposition and the effects of outgassing can be reduced. Moreover, by adjusting the height of the support part J1 so that the distance between the base 20 and the jig J is 0.5 mm or more, the gas during ALD film deposition can be directed to the bottom surface 22a of the recess 22 of the connecting part 22, suppressing unevenness in film deposition of the surface electrode 23.

[0049] (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.

[0050] 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]

[0051] 20 base 21 Curved part 21a surface 22 Connection part 23 Surface electrode

Claims

1. A micro-vibrating body capable of vibrating in wine glass mode, A base portion (20) having a curved surface portion (21) having an annular curved surface, and a bottomed cylindrical connecting portion (22) that is recessed from the surface (21a) of the curved surface portion toward the center of the virtual hemisphere formed by the curved surface portion, The base comprises a surface electrode (23) that covers at least a portion of the surface of the base, The base is made of glass, The aforementioned surface electrode is a micro-vibrating body formed by atomic layer deposition, and is an oxynitride film mainly composed of Ti with added oxygen.

2. The micro-vibrating body according to claim 1, wherein the surface electrode has a Ti-O composition in the range of 26 to 52 wt%.

3. A method for manufacturing a micro-vibrating body that can vibrate in wine glass mode, A base (20) made of glass is provided, having a curved surface portion (21) having an annular curved surface and a bottomed cylindrical connecting portion (22) that is recessed from the surface (21a) of the curved surface portion toward the center of the virtual hemisphere formed by the curved surface portion. A jig (J) is provided that has a support portion (J1) that can be inserted into the connecting portion and support the base portion, The process includes inserting the support portion into the connecting portion and forming a surface electrode (23) covering the surface by atomic layer deposition while holding the base portion in the jig, In preparing the jig, the end of the tip surface of the support part is not chamfered. A method for manufacturing a micro-vibrating body, wherein, in forming the surface electrode, the base is held in a state where it does not come into contact with a part of the jig other than the support part, and a nitride film mainly composed of Ti is formed.

4. The method for manufacturing a micro-vibrating body according to claim 3, wherein the jig is prepared such that its surface is covered with aluminum oxide.

5. It is an inertial sensor, A micro-vibrating body (2) having a curved surface portion (21) having an annular curved surface, a base portion (20) having a bottomed cylindrical connecting portion (22) that is recessed from the surface (21a) of the curved surface portion toward the center of the virtual hemisphere formed by the curved surface portion, and a surface electrode (23) covering at least a part of the surface of the base portion, wherein the curved surface portion is capable of vibrating in wine glass mode, The mounting substrate (3) to which the connection portion is joined has a rim (211) at the end of the curved portion opposite to the connection portion, and a plurality of electrode portions (53) arranged to surround the rim at a distance from each other. The base is made of glass, The surface electrode is formed by atomic layer deposition and is an oxynitride film mainly composed of Ti with added oxygen, in an inertial sensor.

6. A method for manufacturing an inertial sensor comprising a minute vibrating body (2) capable of vibrating in wine glass mode, which is bonded to a mounting substrate (3), A base (20) made of glass is provided, having a curved surface portion (21) having an annular curved surface and a bottomed cylindrical connecting portion (22) that is recessed from the surface (21a) of the curved surface portion toward the center of the virtual hemisphere formed by the curved surface portion. A jig (J) is provided that has a support portion (J1) that can be inserted into the connecting portion and support the base portion, The support portion is inserted into the connecting portion, and while the base portion is held in the jig, a surface electrode (23) covering the surface is formed by atomic layer deposition to form the micro-vibrating body. This includes preparing the aforementioned mounting substrate and joining the connection portion of the micro-vibrator to the aforementioned mounting substrate, A method for manufacturing an inertial sensor, wherein the surface electrode is formed by depositing an oxynitride film mainly composed of Ti with added oxygen.

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