Method for manufacturing micro-vibrator

Abstract

To provide a method for manufacturing a micro-vibrator including a curved surface portion having a three-dimensional curved surface capable of suppressing surface irregularities of the die from being transferred to the curved surface portion while facilitating shape control for the curved surface portion.SOLUTION: A die 100 includes: a recessed portion 110; and a support portion 120 protruding from a center of the recessed portion. A method for manufacturing a micro-vibrator includes: setting a thermoplastic workpiece 10 so as to cover the recessed portion 110 of the die 100; heating the workpiece 10, and simultaneously reducing pressure in the recessed portion 110 closed by the workpiece 10; and, while heating the workpiece 10, exhausting heat from the die 100 so as to maintain temperature of the die 100 below the softening point of the workpiece 10.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing a micro-vibrator having a three-dimensional curved surface. [Background technology]

[0002] In recent years, the development of autonomous driving systems for vehicles has progressed, and this type of system requires highly accurate self-location estimation technology. For example, development of a self-location estimation system equipped with GNSS and IMU for so-called level 3 autonomous driving is underway. GNSS is an abbreviation for Global Navigation Satellite System. IMU is an abbreviation for Inertial Measurement Unit, and is, for example, a 6-axis inertial sensor consisting of a 3-axis gyro sensor and a 3-axis acceleration sensor. In order to realize so-called level 4 or higher autonomous driving in the future, an IMU with even higher accuracy than the current one will be required.

[0003] A method for manufacturing a micro-vibrator used in such an inertial sensor is described in, for example, Patent Document 1. The method for manufacturing a micro-vibrator described in Patent Document 1 includes preparing a mold having a recess and a support part protruding from the center of the bottom surface of the recess, capable of vacuum decompression within the recess, and a reflow material such as a quartz plate, and placing the reflow material on the recess and heating it with a flame or the like while decompressing the recess. As a result, a part of the reflow material softened by heating is pulled into the recess, while the center of the softened part is supported by the support part, and a micro-vibrator having a curved surface part having a three-dimensional curved surface and a cylindrical connection part with a bottom recessed toward the center of the hemispherical part formed by the curved surface part can be manufactured. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent Application Publication No. 2018 / 0079129 Summary of the Invention [Problem to be solved by the invention]

[0005] A promising method for locally heating and softening the reflow material is to use flames from a gas burner or the like, as in the manufacturing method described in Patent Document 1. This manufacturing method forms the curved portion without bringing the softened reflow material into contact with the wall surface of the recess, so there is a high degree of freedom in the finish of the curved portion, and although it is difficult to control the shape, the surface unevenness of the curved portion is small, and a decrease in the Q value of the vibration characteristics can be suppressed.

[0006] However, since the flame of the gas burner is always fluctuating, it is difficult to precisely control the shape and size of the flame that heats the reflow material. Therefore, in the above manufacturing method, the fluctuation of the flame causes uneven heating, making it difficult to control the shape of the curved surface of the micro-vibrator. It is also possible to bring the softened reflow material into contact with the wall surface of the recess and control the shape to match the curved shape of the recess. Although this method makes it easy to control the shape of the curved surface, the surface unevenness of the recess is transferred to the curved surface, resulting in a decrease in the Q value.

[0007] In consideration of the above points, the present disclosure aims to provide a manufacturing method for a micro-vibration body having a curved portion with a three-dimensional curved surface, which facilitates control of the shape of the curved portion while suppressing the transfer of surface irregularities of a mold to the curved portion. [Means for solving the problem]

[0008] According to one aspect of the present disclosure, a method for manufacturing a micro-vibration body having a curved portion (21) having a three-dimensional curved surface and a bottomed tubular connecting portion (22) recessed from the curved portion includes setting a thermoplastic processing material (10) in a mold (100) having a recess (110) and a support portion (120) protruding from the center of the recess, heating the processing material and reducing the pressure in the recess blocked by the processing material to deform the processing material to conform to the recess, and maintaining the mold at a temperature below the softening point of the processing material while heating the processing material.

[0009] As a result, a thermoplastic processing material is set in a mold and heated to be softened, while the depression of the mold blocked by the processing material is decompressed to deform the processing material along the depression, forming a three-dimensional curved surface. At this time, by maintaining the temperature of the mold below the softening point of the processing material during heating, the closer the softened and deformed processing material approaches the inner wall surface of the mold's depression, the greater the amount of heat discharged from the processing material to the mold, and the processing material is prevented from deforming in the softened portion and does not come into contact with the inner wall surface of the depression. On the other hand, the portion that is not close to the inner wall surface of the depression continues to deform so as to approach the inner wall surface of the depression because the heating effect is greater than the heat discharge effect, but the deformation is suppressed as the distance to the inner wall surface decreases. Therefore, the processing material can be easily deformed along the depression of the mold, and the method for manufacturing a micro-vibration body that can suppress the transfer of the surface unevenness of the inner wall surface of the mold by preventing the processing material from coming into contact with the inner wall surface of the depression due to the suppression of deformation due to heat discharge.

[0010] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and specific components described in the embodiments described below. [Brief description of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view showing an example of an inertial sensor including a micro-vibrator according to an embodiment. [Diagram 2] 1 is a cross-sectional view showing a micro-vibrator according to an embodiment. [Diagram 3] FIG. 2 is a perspective view of the inertial sensor of FIG. [Figure 4] FIG. 2 is a diagram showing a first step in the manufacturing process of the micro-vibrator. [Diagram 5] FIG. 5 is a diagram showing a second step following FIG. 4. [Figure 6] 1A to 1C are explanatory diagrams of heat conduction and heat exhaust in the manufacturing process of a micro-vibrator. [Figure 7] FIG. 13 is a diagram showing the relationship between the distance between a processing material and a mold and the amount of heat. [Figure 8] 6 is a diagram showing a manufacturing process of a micro-vibration body of a comparative example, and corresponds to FIG. 5. FIG. [Figure 9] FIG. 6 corresponds to FIG. 5 and shows a modified example of heat dissipation in a mold. [Figure 10] FIG. 7 corresponds to FIG. 5 and shows another modified example of the mold heat exhaust method. [Figure 11] FIG. 13 is a diagram showing another example of a mold used for manufacturing a micro-vibrator. [Figure 12] FIG. 12 is an enlarged cross-sectional view of region XII in FIG. [Figure 13] FIG. 13 is a diagram showing another example of a mold used for manufacturing a micro-vibrator. [Figure 14] FIG. 13 is a diagram showing another example of a mold used for manufacturing a micro-vibrator. [Figure 15] FIG. 13 is a diagram showing another example of a mold used for manufacturing a micro-vibrator. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be denoted by the same reference numerals.

[0013] (Embodiment) An example of an inertial sensor 1 using a micro-vibrator 2 according to an embodiment will be described with reference to the drawings.

[0014] Fig. 1 corresponds to a cross-sectional view taken along line II in Fig. 3, and in order to make the configuration of the inertial sensor 1 easier to understand, the outlines of a first electrode portion 53 and an electrode film 531, which are located in another cross section and will be described later, are shown by dashed lines. In Fig. 3, in order to make the configuration of the inertial sensor 1 easier to understand, a micro-vibrator 2, a lower substrate 4, and an upper substrate 5, which will be described later, of the inertial sensor 1 are omitted, and a cross-sectional configuration of the micro-vibrator 2 is partially shown.

[0015] For the sake of convenience, as shown in FIG. 3, one direction in the plane of the mounting substrate 3 (described later) is referred to as the "x direction", another direction perpendicular to the one direction on the same plane is referred to as the "y direction", and the normal direction to the xy plane is referred to as the "z direction". The x, y, and z directions in figures other than FIG. 3 correspond to the x, y, and z directions in FIG. 3, respectively. In addition, in this specification, "upper" refers to the direction along the z direction in the figure, and refers to the side indicated by the arrow, and "lower" refers to the opposite side to the upper side. In addition, in this specification, the state in which the inertial sensor 1, the micro-vibrator 2, or the mounting substrate 3 is viewed from above in the z direction may be referred to as "top view".

[0016] [Inertial Sensor] 1, the inertial sensor 1 includes a micro-vibrator 2 and a mounting substrate 3, and a part of the micro-vibrator 2 is joined to the mounting substrate 3. The inertial sensor 1 is capable of detecting an angular velocity applied to the inertial sensor 1 based on a change in electrostatic capacitance between a part of the thin-walled micro-vibrator 2 capable of vibrating in a wine glass mode and a plurality of first electrode portions 53 of the mounting substrate 3, for example.

[0017] In this embodiment, as shown in FIG. 1, for example, the micro-vibration body 2 includes a curved surface portion 21 including an external shape of a three-dimensional curved surface of a substantially hemispherical shape, and a connection portion 22 extending from the apex side of the imaginary hemisphere formed by the curved surface portion 21 toward the center side of the hemisphere. The micro-vibration body 2 can also be called an oscillator or a resonator. The connection portion 22 is a cylindrical recess with a bottom, and is a connection portion that is connected to another member such as a mounting board 3. The micro-vibration body 2 is, for example, birdbath-shaped with the curved surface portion 21 being a three-dimensional curved surface in the shape of a bowl, and the Q value of the vibration is 10 5 That's all.

[0018] In this embodiment, the micro-vibrator 2 has a base having the curved surface portion 21 and the connection portion 22, which is made of a thermoplastic reflow material made of glass containing additives such as quartz glass, borosilicate glass, or the like, metallic glass, silicon, or the like. The curved surface portion 21 and the connection portion 22 of the base of the micro-vibrator 2 are formed by a manufacturing process described later, but are not limited to the above-mentioned example of the reflow material. The micro-vibrator 2 has a size on the order of millimeters, such as a thickness of the curved surface portion 21 and the connection portion 22 of 10 μm to 100 μm, a dimension in the z direction of 2.5 mm, and an outer diameter of the surface 2a side of the rim 211 described later of 5 mm. The manufacturing process of the micro-vibrator 2 will be described later.

[0019] The end of the curved surface portion 21 opposite to the connection portion 22 is the rim 211, and the rim 211 is, for example, substantially cylindrical. The substantially cylindrical shape includes not only a cylindrical shape in which the diameter from the upper end to the lower end of the outer surface and the inner surface of the rim 211 is the same, but also a tubular shape in which the diameter from the upper end to the lower end varies. In other words, the curved surface portion 21 has the rim 211 that is an annular portion of an annular curved surface shape. When the micro-vibrator 2 is mounted on the mounting board 3, the surface 2a of the rim 211 faces the multiple first electrode parts 53 of the mounting board 3 at a distance. The micro-vibrator 2 is mounted so that the rim 211 and the multiple first electrode parts 53 are spaced apart from each other, as shown in FIG. 3, for example. 2, the micro-vibrator 2 has a configuration in which a surface of the rim 211 that faces the z direction and connects the front surface 2a and the back surface 2b is the undersurface 211a, and the undersurface 211a protrudes downward in the z direction from the mounting surface 22b. When mounted on the mounting board 3, the micro-vibrator 2 is a portion in which the curved surface portion 21 including the rim 211 is in a hollow state and does not come into contact with other members. In this embodiment, the micro-vibrator 2 has a three-dimensional symmetrical structure in which the hollow rim 211 can vibrate in a wine glass mode when mounted on the mounting board 3.

[0020] The connection portion 22 is a connection portion that is connected to another member such as the mounting substrate 3, and is a cylindrical recess with a bottom. A recess bottom surface 22a on the front surface 2a side of the connection portion 22 can be used, for example, for suction and transportation when mounting the micro-vibrator 2 on the mounting substrate 3. The side of the connection portion 22 opposite to the recess bottom surface 22a, i.e., the surface on the back surface 2b side, is a mounting surface 22b that faces the mounting substrate 3.

[0021] The surface electrode 23 is, for example, but not limited to, a laminated film of an adhesive layer formed of chromium or titanium from the base side and a conductive layer formed of any conductive material such as gold or platinum. The surface electrode 23 is formed on the front surface 2a and the back surface 2b of the micro-vibrator 2 by any film formation method such as sputtering, vapor deposition, CVD, or ALD. CVD is an abbreviation for Chemical Vapor Deposition. ALD is an abbreviation for Atomic Layer Deposition. The surface electrode 23 is formed on at least the mounting surface 22b and the front surface 2a of the rim 211, for example, and these parts are electrically connected. The surface electrode 23 may be a solid shape that covers the entire front and back surfaces of the micro-vibrator 2, or may be a pattern shape that covers a part of the front and back surfaces. For example, the part of the surface electrode 23 that covers the mounting surface 22b of the connection portion 22 of the micro-vibrator 2 is connected to the mounting board 3 via the bonding member 52.

[0022] The mounting substrate 3 includes a lower substrate 4 and an upper substrate 5, which are bonded together, as shown in FIG. 1, for example. For example, the mounting substrate 3 is obtained by subjecting the lower substrate 4, which is made of borosilicate glass, an insulating material, to etching and wiring film formation, and then an upper substrate 5, which is made of silicon, a semiconductor material, to the lower substrate 4 by anodizing and patterning. The mounting substrate 3 includes, for example, on the upper substrate 5 side, a plurality of inner frame portions 51, a plurality of first electrode portions 53 arranged apart from each other so as to surround the inner frame portion 51, and a second electrode portion 54 surrounding the plurality of first electrode portions 53 at a distance. The mounting substrate 3 also includes, for example, on the lower substrate 4 side, a ring-shaped groove 41 surrounding the plurality of inner frame portions 51 while separating the inner frame portion 51 from the plurality of first electrode portions 53, and a plurality of wirings 42 spanning the inside and outside of the groove 41.

[0023] 3, the groove 41 is a groove provided between the inner frame portion 51 and the multiple first electrode portions 53, and is formed by wet etching. The groove 41 has a dimension corresponding to the outer diameter of the rim 211 of the micro-vibrator 2, and is provided so that the rim 211 does not come into contact with the mounting substrate 3 when the micro-vibrator 2 is mounted on the mounting substrate 3.

[0024] The wiring 42 is made of a conductive material such as aluminum, and is disposed so as to pass between the first electrode portions 53 and is electrically independent from the first electrode portions 53. For example, a plurality of wirings 42 are provided, and one end of each wiring 42 is connected to the inner frame portion 51 and the other end is connected to the second electrode portion 54 while straddling the groove 41 in the lower substrate 4, electrically connecting these together. This allows the mounting substrate 3 to apply a voltage to the surface electrode 23 of the micro-vibrator 2 via the second electrode portion 54, the wiring 42, and the inner frame portion 51.

[0025] The inner frame portion 51 is formed together with a plurality of first electrode portions 53 and second electrode portions 54, for example, by performing dry etching such as DRIE on the upper substrate 5 anodically bonded to the lower substrate 4. DRIE is an abbreviation for Deep Reactive Ion Etching. The inner frame portion 51 is formed, for example, in a circular ring shape when viewed from above, and is configured so that the connection portion 22 of the micro-vibrator 2 can be inserted into the enclosed area.

[0026] The bonding member 52 is made of any conductive material, such as gold-tin or sintered silver, and fixes the connection portion 22 of the micro-vibrator 2 to the mounting substrate 3 and electrically connects them.

[0027] The first electrode parts 53 each have an electrode film 531 formed on the upper surface thereof, and are arranged at equal intervals from each other so as to form a ring on the xy plane while surrounding the rim 211 of the micro-vibrator 2 at a predetermined distance in top view. The first electrode parts 53 are connected to the electrode film 531 by wires (not shown), for example, and the potential can be controlled by an external circuit board (not shown). The first electrode parts 53 form a capacitor with the rim 211 of the micro-vibrator 2, and the electrostatic capacitance between the rim 211 can be detected. For example, some of the first electrode parts 53 are detection electrodes that detect electrostatic capacitance, and the other parts are drive electrodes that vibrate the micro-vibrator 2 by electrostatic force.

[0028] The second electrode section 54 is, for example, in a frame shape surrounding the inner frame section 51 and the multiple first electrode sections 53 arranged around the inner frame section 51 when viewed from above. The second electrode section 54 has, for example, at least one electrode film 541 made of aluminum or the like on the upper surface, and a wire (not shown) is connected to the electrode film 541. The second electrode section 54 is connected to the surface electrode 23 of the micro-vibration body 2 at least via the wiring 42, and may have any configuration that allows a voltage to be applied thereto, and may have a shape other than a frame shape, may be arranged in a plurality of parts, and the shape, arrangement, etc. may be appropriately changed.

[0029] The above is an example of the basic configuration of the inertial sensor 1. Note that the inertial sensor 1 is not limited to the above configuration, and some configurations of the micro-vibrator 2 and the mounting substrate 3 may be changed. For example, the micro-vibrator 2 may be configured such that the lower surface 211a of the rim 211 facing the z direction and the mounting surface 22b of the connection portion 22 are located on the same plane, or the mounting surface 22b protrudes from the lower surface 211a. For example, when the micro-vibrator 2 is configured such that the mounting surface 22b protrudes from the rim 211, the mounting substrate 3 may be configured without the groove 41.

[0030] [Method of manufacturing a micro-vibrator] Next, a method for manufacturing the micro-vibrator 2, in particular a method for forming a three-dimensional curved surface, will be described with reference to the drawings.

[0031] In Fig. 6, the direction of heat is indicated by thick arrows in order to easily understand the flow of heat from a heating device 300 (described later) to the processing material 10, the mold 100, and the heat dissipation member 200. This is the same for Figs. 9 and 10 (described later).

[0032] 4, a processing material 10 constituting the base of the micro-vibration body 2 and a mold 100 for forming the curved surface portion 21 and the connection portion 22 are prepared. The processing material 10 is, for example, a plate material made of quartz glass with a thickness of 100 μm. The processing material 10 is arranged so as to cover the recess 110 of the mold 100.

[0033] The mold 100 includes, for example, a recess 110, a cylindrical support portion 120 protruding from the bottom of the recess 110, and an exhaust hole 130 communicating with the recess 110 and enabling decompression by a vacuum source (not shown). The mold 100 is made of any material that has a higher heat resistance than the processing material 10, such as carbon or boron nitride, does not react with the softened processing material 10, and has a predetermined thermal conductivity or higher.

[0034] The recess 110 has an inner wall surface 110a that is, for example, a hemispherical shape with a constant radius of curvature, and a plurality of exhaust holes 130 are formed in the vicinity of the support portion 120. The recess 110 is used to form the curved surface portion 21, and constitutes a space closed by the processing material 10, allowing for decompression by the exhaust holes 130. The recess 110 has, for example, a three-dimensionally symmetric curved shape centered on the support portion 120 when viewed from the normal direction to the upper surface 100a, and the inner wall surface 110a has a curved shape according to the design of the curved surface portion 21 of the micro-vibration body 2 to be manufactured.

[0035] The support portion 120 protrudes from the center of the bottom of the inner wall surface 110a in the thickness direction of the mold 100, and is a portion for forming the connection portion 22. The surface of the mold 100 on which the recess 110 is formed and on which the processing material 10 is placed is defined as the upper surface 100a, the opposite surface is defined as the lower surface 100b, and the surface connecting the upper surface 100a and the lower surface 100b is defined as the side surface 100c.

[0036] The heat dissipation member 200 is configured to have a flow path (not shown) through which a coolant (not shown) such as water flows, and is a member that dissipates heat so that the temperature of the mold 100 does not exceed the softening point of the processing material 10. The heat dissipation member 200, for example, diffuses and exhausts heat from the mold 100 while the processing material 10 is being heated, thereby preventing a portion of the processing material 10 that has been softened by heat from coming into contact with the inner wall surface 110a of the recess 110. Hereinafter, for convenience of explanation, the portion of the processing material 10 that has been softened by heating will be referred to as the "softened portion."

[0037] Next, as shown in FIG. 5, the processing material 10 set in the mold 100 is heated by the heating device 300. The heating device 300 is, for example, a burner, and uses a flame F to locally heat the portion of the processing material 10 covering the recess 110. The heat input from the flame F of the heating device 300 causes a softened portion of the processing material 10 that exceeds its softening point. Then, by reducing the pressure of the closed space formed by the recess 110 and the processing material 10 in the mold 100, the softened portion of the processing material 10 is pushed by atmospheric pressure and deforms along the inner wall surface 110a of the recess 110 and the support portion 120. At this time, the processing material 10 has a shape having a curved portion 11 that is pulled toward the inner wall surface 110a and deformed, and a support portion 12 supported by the support portion 120. The curved portion 11 of the processing material 10 becomes the curved portion 21, and the support portion 12 becomes the connection portion 22. Moreover, heat is input to the mold 100 from the softened portion of the material 10 to be processed, and the heat of the mold 100 is transferred to the heat dissipation member 200 and is then discharged to the outside.

[0038] 6, the heat dissipation member 200 cools the mold 100 and maintains the temperature of the mold 100 so as not to exceed the softening point of the processing material 10. This is to prevent the softened portion of the processing material 10 from contacting the inner wall surface 110a of the recess 110 and to prevent the surface irregularities of the inner wall surface 110a from being transferred to the processing material 10.

[0039] According to Fourier's heat transfer equation shown below in equation (1), the amount of heat transferred between two objects is proportional to the temperature difference between the two objects, and increases as the distance between the two objects decreases.

[0040]

number

[0041] According to the study by the present inventors, it was found that when the temperatures of two objects, i.e., the processing material 10 and the mold 100, are constant, the amount of heat transferred between the two objects has a logarithmic relationship with the distance between the two objects, as shown in Fig. 7. The amount of heat on the vertical axis in Fig. 7 is the relative amount of heat transferred when the amount of heat transferred when the distance between the processing material 10 and the mold 100 is 1 mm is set to 1. Note that Fig. 7 shows the relationship between the distance between the processing material 10 and the mold 100 and the amount of heat transferred therebetween when the temperature difference between the processing material 10 and the mold 100 is constant.

[0042] In other words, if the mold 100 is constantly dissipating heat and the temperature difference with the workpiece 10 is maintained at a predetermined level or greater, the amount of heat dissipated from the workpiece 10 to the mold 100 will be very large before the workpiece 10 comes into contact with the inner wall surface 110a of the recess 110, and the thermal deformation of the workpiece 10 will stop.

[0043] Specifically, in the portion of the material 10 far from the inner wall surface 110a of the recess 110, the heat input from the flame F is greater than the heat exhausted through the mold 100, so the material 10 continues to thermally deform until the distance from the inner wall surface 110a becomes equal to or less than a predetermined distance, gradually approaching the inner wall surface 110a. At this time, even if the heat input to the material 10 varies due to the fluctuation of the flame F, by ensuring the time for thermal deformation, the variation in the thermal deformation of the material 10 can be suppressed, and the variation in the shape of each individual product can be reduced.

[0044] Then, in the softened portion of the processing material 10, the portion that is at a distance from the inner wall surface 110a of the recess 110 or less than a predetermined distance, i.e., the adjacent portion, is farther away from the flame F and the closer it is to the inner wall surface 110a, the greater the heat transfer to the mold 100. Therefore, the adjacent portion of the processing material 10 receives more heat exhausted through the mold 100 than heat input from the flame F, and the temperature becomes lower than the softening point, and thermal deformation stops. In other words, the mold 100 exhausts heat by the heat dissipation member 200 and always maintains a temperature below the softening point of the processing material 10, so that the adjacent portion of the processing material 10 and the inner wall surface 110a are kept in a non-contact state, and the surface unevenness of the inner wall surface 110a is not transferred to the processing material 10.

[0045] Therefore, by exhausting heat from the mold 100 and maintaining the temperature below the softening point of the processing material 10, it is possible to manufacture a micro-vibration body 2 having excellent vibration characteristics, while having a symmetrical shape that roughly follows the curved shape of the inner wall surface 110a of the recess 110, without transferring the surface irregularities of the inner wall surface 110a.

[0046] The portion of the processing material 10 that protrudes from the recess 110 to the outside remains unprocessed, but is removed in a later process. For example, the recess 110 of the mold 100 is returned to normal pressure, the processing material 10 with the approximately hemispherical curved surface portion 21 formed thereon is removed from the mold 100, and the processing material 10 is sealed with a sealant made of any hardening resin material. After that, for example, unnecessary portions of the processing material 10 after processing, including the sealant, are removed by polishing and CMP, and then the sealant is removed by any method such as heating or using a chemical solution, and the remaining portion of the processing material 10 is taken out. CMP is an abbreviation for Chemical Mechanical Polishing. The base of the micro-vibration body 2 is manufactured by, for example, the manufacturing process as described above, but is not limited to the above manufacturing method example, except for the process of forming the curved surface portion 11 and the support portion 12, and other known methods may be adopted. For example, the base of the micro-vibrator 2 may be formed by removing unnecessary portions outside the curved portion 11 by laser processing, without sealing the processing material 10 in which the curved portion 11 and the support portion 12 are formed. Thereafter, by forming a surface electrode 23 on the base of the micro-vibrator 2 by any film forming method, it is possible to manufacture a micro-vibrator 2 in which the curved portion 21 has high three-dimensional symmetry and in which the surface unevenness of the mold 100 is not transferred.

[0047] On the other hand, as shown in FIG. 8, a comparative mold 400 having a substantially cylindrical recess 410, a support 420 protruding from the center of the bottom surface of the recess 410, and a plurality of exhaust holes 430 provided in the recess 410 is used, and a case where the temperature control of the mold 400 is not performed is considered. In this case, when the heat input from the flame F varies, the processed material 10 has a difference in thermal deformation between a portion with a large heat input and a portion with a small heat input, and a difference Hd in height of the curved surface portion 11 occurs, resulting in an asymmetric shape. The Q value of such an asymmetrical shape of the vibrator is reduced. In addition, when the time for thermal deformation is sufficiently secured, the processed material 10 deforms along the recess 410, but if the heat of the mold 400 is not exhausted, the softened portion comes into contact with the wall surface or bottom surface of the recess 410, and the surface unevenness of the recess 410 is transferred. In this case, the obtained vibrator has a symmetrical shape, but the Q value is reduced as a result of the transfer of the surface unevenness.

[0048] According to this embodiment, a mold 100 is used that includes a recess 110 whose inner wall surface 110a has a three-dimensional curved surface, and a support portion 120, and the mold 100 is kept at a temperature equal to or lower than the softening point of the processing material 10, thereby making it easy to control the shape of the curved portion 11 and preventing contact with the inner wall surface 110a. This results in a manufacturing method that makes it possible to manufacture a micro-vibration body 2 that has three-dimensionally symmetrical curved surface portions 21 and connecting portions 22, and in which the curved surface portions 21 are free of surface irregularities that would cause a decrease in the Q value of vibration.

[0049] (Modification) (1) In the above, the heat dissipation member 200 is described as a cooling body using a refrigerant (not shown), but the present invention is not limited to this. The heat dissipation member 200 may be configured to be larger in size and not to use a refrigerant (not shown), for example, as shown in FIG. 9. In other words, the heat dissipation member 200 needs to be in contact with at least the lower surface 10b of the mold 100 and dissipate more heat from the mold 100 to the heat dissipation member 200 than from the processing material 10 to the mold 100, and the size, configuration, etc. may be appropriately changed. This modified example also provides the same effects as the above embodiment.

[0050] (2) In the above, heat dissipation from the mold 100 using the heat dissipation member 200 has been described, but heat from the mold 100 may be dissipated without using the heat dissipation member 200. For example, as shown in FIG. 10, the mold 100 may be placed on a base 210, and the side surface 100c of the mold 100 may be air-cooled when the processing material 10 is heated, thereby dissipating heat from the mold 100 to the outside. In this case, it is only necessary that the amount of heat dissipated from the mold 100 to the outside is greater than the amount of heat dissipated from the processing material 10 to the mold 100. This modified example also provides the same effects as the above embodiment.

[0051] (3) The mold 100 may have an elliptical inner wall surface 110a, i.e., a curved surface with a varying radius of curvature, as shown in FIG. 11, for example. In this case, as shown in FIG. 12, for example, the distance D between the workpiece 10 and the inner wall surface 110a when the thermal deformation of the curved portion 11 stops changes. The distance D changes, for example, to 100 to 200 μm when the inner wall surface 110a has a curved shape that draws a nearly perfect circle, and to 10 μm when the inner wall surface 110a has an elliptical shape. In other words, although the degree to which the mold 100 follows the curved portion 11 of the workpiece 10 changes depending on the curved shape of the inner wall surface 110a, it is easy to control the curved portion 21 to a shape that approximately follows the curved shape of the inner wall surface 110a by controlling the exhaust heat.

[0052] In addition, it is preferable that the base portion 121 of the support portion 120 located on the recessed portion 110 side has a curved shape, for example, as shown in Fig. 11. This allows the curved surface portion 11 to deform along the base portion 121 of the support portion 120, and the symmetry of the base of the obtained micro-vibration body 2 can be further improved.

[0053] This modification also provides the same effects as those of the above embodiment.

[0054] (4) As shown in Fig. 13, for example, the mold 100 may have an inner wall surface 110a having a flat portion 111 and a curved portion 112 having a curved surface shape. In other words, the mold 100 may have a configuration in which at least a portion of the inner wall surface 110a has a curved surface shape, and a portion of the inner wall surface 110a may be flat. In this case, for example, the inner wall surface 110a may have the flat portion 111 near the end on the upper surface 100a side and the other portion may be the curved portion 112, but is not limited to this. This modification also provides the same effects as the above embodiment.

[0055] (5) The mold 100 may be configured such that the curved portion of the inner wall surface 110a has a recessed portion 140, and a portion of the inner wall surface 110a is recessed more than other portions, as shown in Fig. 14. When a mold 100 configured in this way is used, the processing material 10 has a shape in which the curved surface portion 11 has a protruding portion 13 protruding toward the recessed portion 140, for example.

[0056] 15, the mold 100 may have a curved portion of the inner wall surface 110a having a protruding portion 150, and a portion of the inner wall surface 110a protrudes more than other portions. When a mold 100 having such a configuration is used, the processing material 10 has a shape in which the curved portion 11 deforms along the protruding portion 150 and has a recessed portion 14 recessed toward the support portion 12.

[0057] Furthermore, although the above describes an example in which inner wall surface 110a has recessed portion 140 or protruding portion 150, inner wall surface 110a may have both recessed portion 140 and protruding portion 150, and may be modified as appropriate depending on the design of the desired vibrator.

[0058] According to this modification, in addition to the effects of the above embodiment, there is also an effect that the resonant frequency of the obtained vibrator can be controlled.

[0059] (Other embodiments) Although the present disclosure has been described based on the embodiment, it is understood that the present disclosure is not limited to the embodiment or structure. The present disclosure 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 disclosure.

[0060] In each of the above embodiments, it goes without saying that the elements constituting the embodiment are not necessarily essential, except when it is specifically stated that they are essential or when it is clearly considered essential in principle. In addition, in each of the above embodiments, when the numbers, values, amounts, ranges, etc. of the components of the embodiment are mentioned, they are not limited to the specific numbers, except when it is specifically stated that they are essential or when it is clearly limited to a specific number in principle. In addition, in each of the above embodiments, when the shapes, positional relationships, etc. of the components are mentioned, they are not limited to the shapes, positional relationships, etc., except when it is specifically stated that they are essential or when it is clearly limited to a specific shape, positional relationship, etc. in principle. [Explanation of symbols]

[0061] 10... processing material, 21... curved surface portion, 22... connection portion, 100... mold, 100a... upper surface 100b...bottom surface, 100c...side surface, 110...recess, 110a...inner wall surface, 111...flat surface 112: curved portion, 120: support portion, 121: base portion, 140: recessed portion, 150: protruding portion 200...Heat dissipation member

Claims

1. A method for manufacturing a micro-vibration body having a curved surface portion (21) having a three-dimensional curved surface and a bottomed tubular connection portion (22) recessed from the curved surface portion, comprising: A thermoplastic processing material (10) is set in a mold (100) having a recess (110) and a support portion (120) protruding from the center of the recess; heating the processing material and reducing the pressure in the recessed portion blocked by the processing material, thereby deforming the processing material along the recessed portion; and maintaining the mold at a temperature equal to or lower than the softening point of the processing material while the processing material is being heated.

2. 2. The method for manufacturing a micro-vibration body according to claim 1, wherein the mold has a curved shape in which at least a part of an inner wall surface (110a) of the recess has a curved surface.

3. The method for manufacturing a micro-vibrator according to claim 1 , wherein the processing material is quartz or glass.

4. 3. The method for manufacturing a micro-vibration body according to claim 2, wherein the mold has at least one of a recess (140) and a protrusion (150) formed in a curved portion of the inner wall surface of the recess.

5. 3. The method for manufacturing a micro-vibration body according to claim 2, wherein the inner wall surface of the recess of the mold has a flat portion (111) and a curved portion (112) having a curved surface shape.

6. 2. The method for manufacturing a micro-vibration body according to claim 1, wherein the mold has a curved surface at a base portion (121) of the support portion on the side of the recess.

7. 7. A method for manufacturing a micro-vibration body as described in any one of claims 1 to 6, wherein in maintaining the mold below the softening point of the processing material, a heat dissipation member (200) is placed on the underside (100b) of the mold opposite the recess, and the mold is cooled by the heat dissipation member.

8. A method for manufacturing a micro-vibration body as described in any one of claims 1 to 6, wherein, in maintaining the mold at or below the softening point of the processing material, the surface of the mold on which the processing material is set is designated as the upper surface (100a), the surface opposite the upper surface is designated as the lower surface (100b), and the surface connecting the upper surface and the lower surface is designated as the side surface (100c), and the mold is cooled from the side surface.

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