Piezoelectric vibration device and method for manufacturing piezoelectric vibration device

Abstract

Provided are a piezoelectric vibration device and a method for manufacturing a piezoelectric vibration device that enable filling of the interior of a holding member with nitrogen gas or the like, without increasing tact time. The method comprises: a sealing material-attached member preparation step S110 for preparing a lid member 10 or a holding member 2 of which one has, in a part of a portion thereof that contacts the other, the sealing material configured in a rectangular frame-like shape in plan view, at least one corner portion 11c of the sealing material 11 having an increased-thickness portion thicker than portions thereof other than the corner portion 11c; a lid member mounting step S120 for contacting the increased-thickness portion with the other to mount the lid member 10 to the holding member 2, the molding member 2 having a piezoelectric element 7 bonded thereto; a tacking step S130 for heating the lid member 10 mounted to the holding member 2 to melt a part of the increased-thickness portion to tack the lid member 10 and the holding member 2 to each other; and a sealing step S140 for melting the sealing material 11 including the increased-thickness portion to seal the lid member 10 and the holding member 2.

Description

Technical Field

[0001] The present invention relates to a piezoelectric vibration device and a method for manufacturing the piezoelectric vibration device.

Background Art

[0002] The piezoelectric vibration device includes, for example, a crystal oscillator using a crystal vibration piece. The crystal oscillator has a crystal vibration piece that is a piezoelectric element, a holding member that holds the crystal vibration piece, and a lid member that seals the holding member. The crystal vibration piece is held in a box-shaped holding member made of an insulator such as ceramic. The crystal oscillator is sealed by a lid member in a state where an electrode of the crystal vibration piece is joined to an electrode in the holding member.

[0003] A method for manufacturing such a piezoelectric vibration device includes a piezoelectric element mounting step, a lid placement step, a lid temporary attachment step, and a lid joining step. In the piezoelectric element mounting step, the piezoelectric element is joined to an electrode pad in the holding member coated with a conductive joining material. In the lid placement step, a lid having a joining member is placed at an opening of the holding member to which the piezoelectric element is joined. In the lid temporary attachment step, a part of the joining member of the lid disposed on the holding member is melted and temporarily attached to the holding member. In the lid joining step, the holding member and the lid are joined in a nitrogen gas atmosphere or a vacuum atmosphere. For example, Patent Document 1 discloses a lid temporary attachment step in which a part of the joining member of the lid is melted by resistance heat and temporarily attached to the holding member by pressing a metal bar against a part of the lid and energizing it.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the method for manufacturing a piezoelectric vibration device described in Patent Document 1, in the lid temporary attachment step, the lid is temporarily fixed to the holding member while the lid is pressed against the holding member by the metal rod. As a result, the lid is temporarily attached to the holding member in a state of being in close contact with the holding member. Therefore, in the lid joining step, it is difficult for the gas generated from the bonding material or the like in the holding member to be discharged from the gap between the lid and the holding member.

[0006] An object of the present invention is to provide a piezoelectric vibration device and a method for manufacturing the piezoelectric vibration device capable of discharging gas generated from a bonding material or the like in a holding member.

Means for Solving the Problems

[0007] The inventors of the present invention have studied a piezoelectric vibration device and a method for manufacturing the piezoelectric vibration device capable of discharging gas generated from a bonding material or the like in a holding member. As a result of intensive studies, the inventors of the present invention have conceived the following configuration.

[0008] A method for manufacturing a piezoelectric vibration device according to an embodiment of the present invention includes at least a piezoelectric element, a holding member to which the piezoelectric element is joined, and a lid member that covers the piezoelectric element joined to the holding member, and is a method for manufacturing a piezoelectric vibration device in which the lid member is joined to the holding member to which the piezoelectric element is joined by a sealing material.

[0009] The manufacturing method of the piezoelectric vibration device includes: when the piezoelectric element joined to the holding member is covered with the lid member, at least a part of the portion in either the lid member or the holding member that contacts the other forms a sealing material configured in a rectangular frame shape in plan view, and preparing a member with a sealing material, in which at least one corner of the sealing material has a thick portion that is thicker than the other portions, in the lid member or the holding member; a lid member mounting step of mounting the lid member on the holding member to which the piezoelectric element is joined by bringing the thick portion of either the lid member or the holding member into contact with the other; a temporary fixing step of heating at least the lid member mounted on the holding member and melting at least a part of the thick portion to temporarily fix the lid member and the holding member; and a sealing step of heating the temporarily fixed lid member and the holding member respectively and melting the sealing material including the thick portion to seal the lid member and the holding member.

[0010] In the above configuration, in the lid member mounting step, the lid member is mounted on the holding member via the sealing material having the thick portion. The lid member is supported at a position separated from the holding member by the thickness of the thick portion by the thick portion. Therefore, in the temporary fixing step, a gap is generated between the lid member and the holding member that are temporarily fixed by melting a part of the thick portion. Therefore, when heating the lid member and the holding member in the atmosphere gas in the sealing step, the atmosphere gas rapidly flows into the holding member from the gap between the lid member and the holding member. Thereby, the gas generated from the bonding material or the like in the holding member can be discharged.

[0011] From another aspect, the manufacturing method of the piezoelectric vibration device of the present invention preferably includes the following configuration. In the temporary fixing step, the lid member is heated by bringing a heating element into contact with a part of the lid member.

[0012] In the above configuration, since the sealing material is in contact with the lid member that is directly heated by the heating element, heat is efficiently transferred from the heating element to the lid member and then to the sealing material. Therefore, in the temporary fixing step, even if the sealing material has a thick portion, the lid member can be temporarily fixed to the holding member without reducing the melting rate of the sealing material. As a result, gases generated from the bonding material or the like within the holding member can be discharged.

[0013] From another perspective, the manufacturing method of the piezoelectric vibration device of the present invention preferably includes the following configuration. In the temporary fixing step, the lid member is heated while being held by the mounting means.

[0014] In the above configuration, in the lid member mounting step, the position of the lid member with respect to the holding member is held by the mounting means that mounts the lid member on the holding member. Therefore, by the temporary fixing step, the positional accuracy of the lid member temporarily fixed to the holding member is improved, and the time required to shift from the lid member mounting step to the temporary fixing step can be shortened. As a result, gases generated from the bonding material or the like within the holding member can be discharged.

[0015] From another perspective, the manufacturing method of the piezoelectric vibration device of the present invention preferably includes the following configuration. In the temporary fixing step, the lid member is pressed by the heating element.

[0016] In the above configuration, in the temporary fixing step, the lid member is pressed against the holding member while being heated by the heating element. Therefore, the melting rate of the thick portion located between the lid member and the holding member increases. As a result, gases generated from the bonding material or the like within the holding member can be discharged.

[0017] From another perspective, the manufacturing method of the piezoelectric vibration device of the present invention preferably includes the following configuration. In the temporary fixing step, the portion of the lid member that overlaps at least a part of the sealing material in plan view is pressed.

[0018] In the above configuration, since the sealing material is located closest to the lid member directly heated by the heating element, heat is efficiently transferred from the heating element through the lid member. Therefore, in the temporary fixing step, even if the sealing material has the thick portion, the lid member can be temporarily fixed to the holding member without reducing the melting rate of the thick portion. Thereby, the gas generated from the bonding material or the like in the holding member can be discharged.

[0019] From another aspect, the method for manufacturing a piezoelectric vibration device of the present invention preferably includes the following configuration. In the temporary fixing step, the heating element is brought into contact with a position on an arbitrary outer edge side of the lid member rather than the center of the lid member in a plan view to heat the lid member.

[0020] In the above configuration, in the temporary fixing step, the heating element is pressed between the center of the lid member and an arbitrary outer edge of the lid member in a plan view. That is, the lid member supported by the holding member at the outer edge is pressed by the heating element at a position closer to the portion supported by the holding member than the center. The amount of elastic deformation of the lid member that occurs when the heating element is pressed against a position on an arbitrary outer edge side of the lid member is smaller than the amount of elastic deformation of the lid member that occurs when the heating element is pressed against the center of the lid member. Therefore, even if the lid member returns to the state before elastic deformation after temporary fixing, the influence on the joint portion is suppressed, so that the lid member is appropriately temporarily fixed to the holding member.

[0021] From another aspect, the method for manufacturing a piezoelectric vibration device of the present invention preferably includes the following configuration. The sealing material is a gold-tin alloy.

[0022] In the above configuration, since the sealing material is a gold-tin alloy, it has high thermal conductivity. That is, the thick portion of the sealing material is quickly heated to the melting temperature. Therefore, in the temporary fixing step, the lid member can be temporarily fixed to the holding member without reducing the melting rate of the thick portion. Thereby, the gas generated from the bonding material or the like in the holding member can be discharged.

[0023] From another perspective, the piezoelectric vibration device of the present invention preferably includes the following configuration. It is a piezoelectric vibration device manufactured by the manufacturing method of each of the above piezoelectric element vibration devices.

[0024] In the above configuration, in the sealing step, when the lid seals the holding member, the piezoelectric vibration device can discharge the gas generated from the bonding material etc. inside the holding member from the gap. Thereby, the piezoelectric vibration device can suppress the deterioration of the piezoelectric element inside the holding member.

[0025] From another perspective, the piezoelectric vibration device of the present invention preferably includes the following configuration. It is a piezoelectric vibration device manufactured by the manufacturing method of each of the above piezoelectric element vibration devices, wherein the sealing material includes a eutectic alloy and a non-eutectic alloy having a melting point higher than that of the eutectic alloy, and the sealing material at at least one corner of the rectangular frame-shaped sealing material in plan view includes the non-eutectic alloy.

[0026] In the above configuration, since the corner portion of the sealing material contains a non-eutectic alloy having a melting point higher than that of the eutectic alloy, it is less likely to melt compared to the corner portion that does not contain the non-eutectic alloy. Also, the corner portion of the sealing material having the thick portion has a relatively larger volume compared to the straight portion, so it is less likely to melt than the side portion. Therefore, when melting the solder to mount (reflow mount) the piezoelectric vibration device on an external substrate, the sealing material is less likely to melt and flow out to the cavity side. Thereby, it is possible to prevent airtightness defects when mounting the piezoelectric vibration device on the external substrate.

[0027] [Eutectic alloy] In this specification, a eutectic alloy means an alloy that solidifies in a state having two types of solid phases from a liquid phase when the alloy solidifies. The eutectic alloy is a gold-tin alloy in the present embodiment. The eutectic alloy has a lower melting point than the non-eutectic alloy. [Advantages of the Invention]

[0028] According to an embodiment of the present invention, it is possible to discharge gas generated from a bonding material or the like in the holding member.

Brief Description of the Drawings

[0029]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 5B

Figure 5C

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

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Figure 12

MODE FOR CARRYING OUT THE INVENTION

[0030] Hereinafter, each embodiment will be described with reference to the drawings. In each figure, the same parts are denoted by the same reference numerals, and the description of the same parts will not be repeated. Note that the dimensions of the constituent members in each figure do not faithfully represent the actual dimensions of the constituent members and the dimensional ratios of the constituent members.

[0031] In the following description of the piezoelectric vibration device 1 according to an embodiment of the present invention, the longitudinal direction of the piezoelectric vibration device 1 is defined as the "X direction", the short-side direction is defined as the "Y direction", and the direction of the opening of the opening in the holding member 2 that holds the piezoelectric element 7 and is orthogonal to the X direction and the Y direction is defined as the "Z direction". In the present embodiment, the X direction and the Y direction are directions on a horizontal plane. The Z direction is the vertical direction. That is, the Z direction is the up-down direction. However, the present invention is not intended to limit the orientation of the piezoelectric vibration device 1 during use by this definition of the directions.

[0032] In the following description, expressions such as "fix", "connect", "join", and "attach" (hereinafter referred to as "fixing, etc.") include not only cases where members are directly fixed, etc., but also cases where they are fixed, etc. via other members. That is, in the following description, the expressions of fixing, etc. include the meanings of direct and indirect fixing, etc. of members to each other.

[0033] [Embodiment 1] <Configuration of Piezoelectric Vibration Device 1> The piezoelectric vibration device 1 of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is an exploded perspective view showing an outline of the overall configuration of the piezoelectric vibration device 1. FIG. 2 is a sectional view taken along the arrow A in FIG. 1. FIG. 3 is a plan view of the piezoelectric vibration device 1.

[0034] As shown in FIGS. 1 and 2, the piezoelectric vibration device 1 is a device having a piezoelectric element 7 that converts a force applied to a piezoelectric body into a voltage or converts a voltage applied to the piezoelectric body into a force. The piezoelectric vibration device 1 includes a holding member 2, a piezoelectric element 7, and a lid member 10.

[0035] The holding member 2 is a container made of an insulator for holding the piezoelectric element 7. The holding member 2 is a housing made of ceramics in the present embodiment. The holding member 2 is formed by sintering ceramic powder. Note that the holding member 2 may be formed by laminating a plurality of insulators. The holding member 2 includes a bottom portion 3, an electrode pad 4, a side wall portion 6, and an external terminal 5.

[0036] The bottom 3 is the part that constitutes the bottom surface of the holding member 2. The bottom 3 is composed of a rectangular plate-like member. On the upper surface, which is one surface of the bottom 3, an electrode pad 4 made of conductive metal is formed along one short side of the rectangular plate-like member. The electrode pad 4 is electrically connected to the piezoelectric element 7. The electrode pad 4 is part of an electric circuit that applies a voltage to the piezoelectric element 7. On the lower surface, which is the other surface of the bottom 3, an external terminal 5 made of conductive metal is deposited. The external terminal 5 is electrically connected to an external substrate (not shown). The external terminal 5 is a terminal for transmitting a signal from the external substrate to the piezoelectric element 7 and applying a voltage. The electrode pad 4 and the external terminal 5 are electrically connected by a wiring pattern (not shown).

[0037] The side wall portion 6 is the part that constitutes the side surface of the holding member 2. The side wall portion 6 is located at the outer edge of the bottom 3. The side wall portion 6 is a frame-shaped wall that surrounds the bottom 3. The side wall portion 6 extends upward from the upper surface of the bottom 3. Also, the side wall portion 6 has a predetermined thickness from the outer surface toward the inner surface. At the upper end portion of the side wall portion 6, there is a joint surface 6a that joins with the lid member 10. The holding member 2 configured in this way constitutes an internal space S that houses the piezoelectric element 7 by the upper surface of the bottom 3 and the inner surface of the side wall portion 6. The holding member 2 is open upward from the upper surface of the bottom 3. The electrode pad 4 is located within the internal space S.

[0038] The piezoelectric element 7 is a piezoelectric body that converts the applied force into voltage or the applied voltage into force. In this embodiment, the piezoelectric element 7 is a rectangular crystal vibrating piece cut out from a crystal in a specific direction. Electrodes 8 are deposited on both of the pair of main surfaces with the largest area of the piezoelectric element 7. A part of the electrode 8 is drawn out to one end in the longitudinal direction of the crystal vibrating piece. The piezoelectric element 7 is located within the internal space S of the holding member 2. The electrodes 8 of the piezoelectric element 7 are adhered to the electrode pads 4 of the holding member 2 by a conductive bonding material 9. Thereby, the piezoelectric element 7 can be electrically connected to an external substrate via the electrode pads 4, a wiring pattern (not shown), and the external terminals 5 from the electrodes 8. Also, the piezoelectric element 7 is held in a cantilever-supported state by the holding member 2. Thereby, the piezoelectric element 7 oscillates at a predetermined frequency by the voltage applied from the external substrate.

[0039] The lid member 10 is a member that seals the internal space S of the holding member 2 into a sealed space. The lid member 10 is made of, for example, a metal material such as Kovar. Also, the lid member 10 is, for example, subjected to electrolytic nickel plating or electroless nickel plating. The lid member 10 is positioned at the upper end of the holding member 2 with its lower surface, which is one surface, facing the holding member 2. The lid member 10 has a size that covers the opening portion of the internal space S in the holding member 2 when viewed in the Z direction in a plan view. Also, when viewed in the Z direction, the lid member 10 is smaller than the holding member 2.

[0040] As shown in FIG. 3, the lid member 10 is provided with a frame-shaped sealing material 11 at a portion that overlaps with the joint surface 6a of the side wall portion 6 in the holding member 2 when viewed in the Z direction. That is, when the lid member 10 covers the internal space S including the piezoelectric element 7 joined to the holding member 2, the lid member 10 has a sealing material 11 that surrounds the opening portion of the holding member 2 at the portion that contacts the joint surface 6a of the holding member 2 when viewed in the Z direction. The sealing material 11 is a gold-tin alloy. The sealing material 11 has two longitudinal straight portions 11b extending in the X direction, two transverse straight portions 11a extending in the Y direction, and four corner portions 11c connecting the longitudinal straight portions 11b and the transverse straight portions 11a when viewed in the Z direction.

[0041] When viewed in the Z direction, the corner area Ar per unit length in the extending direction of the four corner portions 11c (see the hatched portions) is wider than the longitudinal straight portion area Al per unit length in the extending direction of the longitudinal straight portion 11b (see the hatched portions) and the short-side straight portion area As per unit length in the extending direction of the short-side straight portion 11a (see the hatched portions).

[0042] The sealing material 11 contains a eutectic alloy and a non-eutectic alloy having a melting point higher than that of the eutectic alloy. In the present embodiment, the corner portion 11c contains the non-eutectic alloy. Note that the non-eutectic alloy may be included not only in the corner portion 11c but also in at least one of the short-side straight portion 11a and the longitudinal straight portion 11b. The lid member 10 is joined to the joint surface 6a of the holding member 2 by the sealing material 11. The interior space S of the holding member 2 is in a vacuum. Note that the interior space S of the holding member 2 may be filled with nitrogen gas or the like.

[0043] Thus, in the piezoelectric vibration device 1, the piezoelectric element 7 is positioned within the interior space S and The inside of the internal space S is vacuum the holding member 2 is sealed with the lid member 10. The gold-tin alloy joining the lid member 10 to the holding member 2 contains a non-eutectic alloy having a melting point higher than that of the eutectic alloy. Further, since the corner portion 11c has a larger volume per unit length than the short-side straight portion 11a and the longitudinal straight portion 11b, it is more difficult to melt than the straight portions. Therefore, when the piezoelectric vibration device 1 is mounted (reflow-mounted) on an external substrate by melting solder, even if the sealing material 11 melts due to the heat for heating the solder, it is less likely to flow out toward the cavity side. Thereby, the piezoelectric vibration device 1 can suppress airtightness failure during mounting on an external substrate.

[0044] <Manufacturing method of piezoelectric vibration device 1> Next, with reference to FIGS. 4 to 8, a piezoelectric element sealing step S100 included in the manufacturing method of the piezoelectric vibration device 1 of the present invention will be described. FIG. 4 is a flowchart of the piezoelectric element sealing step S100 included in the manufacturing method of the piezoelectric vibration device 1. FIG. 5A is a plan view of the lid member 10 prepared in the member preparation step S110 with a sealing material included in the manufacturing method of the piezoelectric vibration device 1. FIG. 5B is a side view in the short side direction of the lid member 10 prepared in the member preparation step S110 with a sealing material included in the manufacturing method of the piezoelectric vibration device 1. FIG. 5C is a side view in the long side direction of the lid member 10 prepared in the member preparation step S110 with a sealing material included in the manufacturing method of the piezoelectric vibration device 1. FIG. 6 is a cross-sectional view taken along the arrow A in FIG. 3 in the holding member 2 and a side view of the lid member 10 mounted on the holding member 2 in the lid member mounting step S120 included in the manufacturing method of the piezoelectric vibration device 1. FIG. 7 is a cross-sectional view showing the side view of the lid member 10 heated by the soldering iron 13 and the holding member 2 heated by the holding member heating device 14 in the temporary fixing step S130 included in the manufacturing method of the piezoelectric vibration device 1. FIG. 8 is a cross-sectional view showing the lid member 10 heated and pressed by the lid member heating device 15 and the holding member 2 heated by the holding member heating device 14 in the sealing step S140 included in the manufacturing method of the piezoelectric vibration device 1.

[0045] As shown in FIG. 4, the piezoelectric element sealing step S100 is a step of sealing the piezoelectric element 7 located in the internal space S of the holding member 2 with the lid member 10 (see FIG. 2). The piezoelectric element sealing step S100 includes a member preparation step S110 with a sealing material, a lid member mounting step S120, a temporary fixing step S130, and a sealing step S140.

[0046] In the initial state of the piezoelectric vibration device 1, the piezoelectric element 7 is incorporated in the holding member 2. The piezoelectric element 7 is joined to the electrode pad 4 of the holding member 2 by a bonding material. That is, the piezoelectric element 7 is incorporated in the internal space S of the holding member 2 in a state where it can oscillate by applying a voltage.

[0047] As shown in FIGS. 4, 5A, 5B, and 5C, the step S110 of preparing the member with the sealing material is a step of preparing the lid member 10 which is a member with the sealing material 11 provided in a predetermined state. In the step S110 of preparing the member with the sealing material, when the piezoelectric element 7 joined to the holding member 2 is covered by the lid member 10 in the lid member 10 to be prepared, the sealing material 11 is applied to a portion that contacts the holding member 2 on the lower surface which is the surface facing the piezoelectric element 7 in the lid member 10 (see FIG. 3). The sealing material 11 is a eutectic state gold-tin alloy.

[0048] The sealing material 11 provided on the lid member 10 is configured in a rectangular frame shape when viewed in a direction perpendicular to the lower surface in a plan view. That is, the sealing material 11 includes two short-side straight portions 11a extending linearly along the short side direction of the lid member 10, two long-side straight portions 11b extending linearly along the long side direction of the lid member 10, and four arc-shaped corner portions 11c connecting the short-side straight portion 11a and the long-side straight portion 11b, respectively. The short-side straight portion 11a and the long-side straight portion 11b extend in directions substantially perpendicular to each other. The four corner portions 11c have a predetermined curvature. The corner portions 11c contain a non-eutectic alloy.

[0049] The radial width Wr at the four corner portions 11c is larger than the width Wl in the short side direction of the lid member 10 at the two long-side straight portions 11b and the width Ws in the long side direction of the lid member 10 at the two short-side straight portions 11a. Also, the four corner portions 11c each have a thick portion with a thickness Tr that is thicker than the thickness Tl in the direction perpendicular to the lower surface at the two long-side straight portions 11b and the thickness Ts in the direction perpendicular to the lower surface at the two short-side straight portions 11a. That is, the four corner portions 11c protrude in a direction perpendicular to the lower surface of the lid member 10 more than the short-side straight portion 11a and the long-side straight portion 11b. Therefore, the volume per unit length in the extending direction of the four corner portions 11c of the sealing material 11 is larger than the volume per unit length at the short-side straight portion 11a and the long-side straight portion 11b.

[0050] As shown in FIGS. 4, 6, and 7, the lid member mounting step S120 is a step of mounting the lid member 10, which is a member with a sealing material prepared in the member preparation step S110 with a sealing material, on the holding member 2. In the lid member mounting step S120, the holding member 2 is placed on the holding member heating device 14. Further, the holding member 2 is preheated by the holding member heating device 14 and maintained at a predetermined temperature. The lid member 10 is adsorbed by the suction nozzle 12 of the transfer device, which is a mounting means. The lid member 10 is mounted on the holding member 2 by the suction nozzle 12 with the lower surface provided with the sealing material 11 facing the holding member 2. In the lid member 10, the thick portion of the corner portion 11c of the sealing material 11 provided on the lower surface contacts the joint surface 6a of the holding member 2. On the other hand, among the sealing material 11, the short-side straight portion 11a and the long-side straight portion 11b do not contact the joint surface 6a.

[0051] As shown in FIGS. 4 and 7, the temporary fixing step S130 is a step of temporarily fixing the lid member 10 mounted on the holding member 2 in the lid member mounting step S120 to the holding member 2. In the temporary fixing step S130, the soldering iron 13, which is a heating element, is brought into contact with the upper surface of the lid member 10. The soldering iron 13 is located at approximately the center in the short-side direction and approximately the center in the long-side direction of the lid member 10. The lid member 10 is heated to a predetermined temperature by the soldering iron 13. Next, the sealing material 11 provided on the lid member 10 is heated by the lid member 10. Further, the sealing material 11 is heated by the holding member 2 maintained at a predetermined temperature by the holding member heating device 14.

[0052] In the lid member 10, a part of the thick portion of the corner 11c melts. When the soldering iron 13 reaches a predetermined heating temperature and a predetermined heating time, it separates from the lid member 10. Thus, in the lid member mounting step S120, the lid member 10 is heated by the soldering iron 13 while the holding member 2 is heated by the holding member heating device 14. Therefore, the sealing material 11 melts earlier compared to melting only by the heat from the soldering iron 13. Note that the melting amount of the thick portion of the corner 11c is adjusted by the contact position of the soldering iron on the lid member 10, the contact area of the soldering iron with the lid member 10, the heating time of the lid member 10 by the soldering iron, and the heating temperature of the lid member 10 by the soldering iron.

[0053] The sealing material 11 joins to the joint surface 6a of the holding member 2 in a state where the thickness Tr of the thick portion of the corner 11c has become thinner by the melting due to the heating of the soldering iron 13. By going through the temporary fixing step S130, the sealing material 11 melts by the soldering iron 13 and the heated holding member 2 and then solidifies to form a non-eutectic alloy having a melting point higher than that of the eutectic alloy. On the other hand, the short-side straight portion 11a and the long-side straight portion 11b of the sealing material 11 do not contact the joint surface 6a of the holding member 2. That is, a gap is formed between the short-side straight portion 11a and the long-side straight portion 11b of the sealing material 11 in the lid member 10 and the joint surface 6a of the side wall portion 6 in the holding member 2.

[0054] As shown in FIGS. 4, 7, and 8, the sealing step S140 is a step of sealing the holding member 2 with the lid member 10 temporarily fixed to the holding member 2 in the temporary fixing step S130. In the sealing step S140, the lid member 10 and the holding member 2 are each heated in a vacuum. The holding member 2 is heated to a predetermined temperature by the holding member heating device 14. The lid member 10 is heated to a predetermined temperature by the lid member heating device 15 and is pressed toward the holding member 2. The sealing material 11 melts by the heat from the holding member heating device 14 and the lid member heating device 15.

[0055] As the melting of the thick portion of the corner portion 11c progresses, the short-side straight portion 11a and the long-side straight portion 11b approach the joint surface 6a. At this time, inside the internal space S of the holding member 2, gas is generated from the bonding material 9 or the like that bonds the piezoelectric element 7 to the electrode pad 4. The generated gas is discharged to the outside of the internal space S through the gap between the short-side straight portion 11a and the long-side straight portion 11b and the joint surface 6a.

[0056] When the thickness Ts of the short-side straight portion 11a, the thickness Tl of the long-side straight portion 11b, and the thickness Tr of the corner portion 11c become substantially the same due to the melting of the thick portion of the corner portion 11c, the short-side straight portion 11a, the long-side straight portion 11b, and the corner portion 11c come into contact with the joint surface 6a. That is, the lid member 10 contacts the joint surface 6a via the sealing material 11. When the sealing material 11 is cooled, it joins the holding member 2 and the lid member 10. Thereby, the opening of the holding member 2 is sealed by the lid member 10. At this time, the internal space S of the holding member 2 is in a vacuum state.

[0057] In the manufacturing method of the piezoelectric vibration device 1 configured as described above, in the lid member mounting step S120, the lid member 10 is mounted on the holding member 2 via the sealing material 11. The lid member 10 is supported at a position separated from the joint surface 6a of the side wall portion 6 by the thickness Tr of the corner portion 11c by the thick portion of the corner portion 11c. Therefore, in the temporary fixing step S130, a gap is generated in a portion other than the thick portion of the corner portion 11c between the lid member 10 temporarily fixed by melting the thick portion of the corner portion 11c and the joint surface 6a of the side wall portion 6 in the holding member 2.

[0058] Therefore, in the sealing step S140, when the holding member 2 and the lid member 10 are heated in a vacuum, the gas generated from the bonding material 9 or the like located inside the internal space S of the holding member 2 is discharged to the outside of the internal space S through the gap between the holding member 2 and the lid member 10. Further, since the lid member 10 provided with the sealing material 11 is directly heated by the soldering iron 13, the heat from the soldering iron 13 is efficiently transmitted to the sealing material 11 through the metal lid member 10. Thereby, the gas generated from the bonding material 9 or the like located inside the internal space S of the holding member 2 can be discharged.

[0059] The holding member 2 and the lid member 10 of the piezoelectric vibration device 1 manufactured by the manufacturing method of the piezoelectric vibration device 1 described above are joined by a sealing material 11 in which the thickness Tr of the corner portion 11c is thicker than the thickness Ts of the short-side straight portion 11a and the thickness Tl of the long-side straight portion 11b. Therefore, when viewed in the Z direction, the corner area Ar per unit length in the extending direction of the four corner portions 11c of the sealing material 11 is wider than the longitudinal straight portion area Al per unit length in the extending direction of the longitudinal straight portion 11b and the short-side straight portion area As per unit length in the extending direction of the short-side straight portion 11a. Further, the sealing material 11 is melted and solidified in the temporary fixing step S130 to generate the non-eutectic alloy. Therefore, the corner portion 11c of the sealing material 11 is less likely to melt than the short-side straight portion 11a and the long-side straight portion 11b. The sealing material 11 of the piezoelectric vibration device 1 configured as described above is less likely to flow out to the cavity side even if it melts when melting the solder on the external substrate for mounting (reflow mounting).

[0060] [Embodiment 2] With reference to FIGS. 4 and 9, the piezoelectric element sealing step S100A included in the manufacturing method of the piezoelectric vibration device 1 according to Embodiment 2 of the present invention will be described. FIG. 9 is a side view of the lid member 10 heated by the soldering iron 13 in the temporary fixing step S130A included in the manufacturing method of the piezoelectric vibration device 1 and a cross-sectional view taken along the arrow A in FIG. 3 of the holding member 2 heated by the holding member heating device 14. In the following embodiments, the specific description of the same points as those in the already described embodiments will be omitted, and the description will be centered on the different parts.

[0061] As shown in FIG. 4, the piezoelectric element sealing step S100A includes a member preparation step S110 with a sealing material, a lid member mounting step S120, a temporary fixing step S130A, and a sealing step S140.

[0062] In the lid member mounting step S120, the lid member 10 is adsorbed by the suction nozzle 12 of the transfer device which is the mounting means. The suction nozzle 12 is located at approximately the center in the short side direction of the lid member 10 and closer to one side than approximately the center in the long side direction. The lid member 10 is mounted on the holding member 2 with the lower surface provided with the sealing material 11 facing the holding member 2.

[0063] As shown in FIGS. 4 and 9, the temporary fixing step S130A is a step of temporarily fixing the lid member 10 mounted on the holding member 2 in the lid member mounting step S120 to the holding member 2. In the temporary fixing step S130A, with the lid member 10 adsorbed by the suction nozzle 12 which is the mounting means, the soldering iron 13 which is a heating element is brought into contact with the upper surface of the lid member 10. The soldering iron 13 is located at approximately the center in the short side direction of the lid member 10 and closer to the other side than approximately the center in the long side direction. That is, in the temporary fixing step S130A, the soldering iron 13 is brought into contact with the lid member 10 at a position on the other outer edge side than the center in the long side direction of the lid member 10 in a plan view. Therefore, the soldering iron 13 is in contact with the lid member 10 at a certain distance away from the suction nozzle 12.

[0064] Furthermore, the lid member 10 is heated to a predetermined temperature by the soldering iron 13 while being adsorbed by the suction nozzle 12. The lid member 10 is heated by the soldering iron 13 and also heated by the holding member 2 which is maintained at a predetermined temperature by the holding member heating device 14. A part of the thick portion of the corner 11c of the sealing material 11 of the lid member 10 melts. At this time, the lid member 10 is joined to the joining surface 6a of the holding member 2 while the position of the lid member 10 with respect to the holding member 2 is held by the suction nozzle 12. When the soldering iron 13 reaches the predetermined heating temperature and the predetermined heating time, it separates from the lid member 10.

[0065] In the above configuration, the lid member 10 is temporarily fixed to the holding member 2 while being held in position with respect to the holding member 2 by the suction nozzle 12. That is, the lid member 10 does not shift in position with respect to the holding member 2 when the thick portion of the corner portion 11c melts. Therefore, the positional accuracy of the lid member 10 with respect to the holding member 2, which is temporarily fixed to the holding member 2 via the thick portion of the corner portion 11c, is improved, and the time required to shift from the lid member mounting step S120 to the temporary fixing step S130 can be shortened. As a result, the gas generated from the bonding material 9 and the like located in the internal space S of the holding member 2 can be discharged without increasing the tact time.

[0066] [Embodiment 3] Using FIGS. 4 and 10, the piezoelectric element sealing step S100B included in the manufacturing method of the piezoelectric vibration device 1 according to Embodiment 3 of the present invention will be described. FIG. 10 is a side view of the lid member 10 heated by the soldering iron 13 in the temporary fixing step S130B included in the manufacturing method of the piezoelectric vibration device 1 and a cross-sectional view taken along the arrow A in FIG. 3 of the holding member 2 heated by the holding member heating device 14.

[0067] As shown in FIG. 4, the piezoelectric element sealing step S100B includes a member preparation step S110 with a sealing material, a lid member mounting step S120, a temporary fixing step S130B, and a sealing step S140.

[0068] As shown in FIGS. 4 and 10, the temporary fixing step S130B is a step of temporarily fixing the lid member 10 to the holding member 2. In the temporary fixing step S130B, the soldering iron 13 is brought into contact with the upper surface of the lid member 10 while the lid member 10 is held by the suction of the suction nozzle 12. The soldering iron 13 is located at a portion that overlaps at least a part of the sealing material 11 when viewed in a direction perpendicular to the upper surface of the lid member 10 (plan view). In the present embodiment, the soldering iron 13 is located at a portion that overlaps the thick portion of the corner portion 11c in the sealing material 11 when viewed in a direction perpendicular to the upper surface of the lid member 10. That is, the soldering iron 13 is located closest to the corner portion 11c having a thickness in the sealing material 11.

[0069] Furthermore, the lid member 10 is heated to a predetermined temperature by the soldering iron 13 and pressed toward the holding member 2 by a predetermined force. The sealing material 11 is heated and pressed by the lid member 10 heated by the soldering iron 13, and is also heated by the holding member 2 maintained at a predetermined temperature by the holding member heating device 14. As a result, a part of the thick portion of the corner 11c melts. When the predetermined heating time and pressing time are reached, the soldering iron 13 separates from the lid member 10.

[0070] In the present embodiment, the soldering iron 13 is brought into contact with a portion that overlaps at least a part of the sealing material 11 in the lid member 10 in a plan view. That is, the soldering iron 13 is brought into contact with a position on the outer edge side rather than the center of the lid member 10 in a plan view.

[0071] The lid member 10 whose outer edge is supported by the holding member 2 is pressed toward the holding member 2 by the soldering iron 13 at a position closer to the portion supported by the holding member 2 than the center of the lid member 10. The lid member 10 elastically deforms toward the holding member 2 by the pressing of the soldering iron 13. The amount of elastic deformation of the lid member 10 that occurs when the soldering iron 13 is pressed at an arbitrary position on the outer edge side rather than the center of the lid member 10 is smaller than the amount of elastic deformation that occurs when the soldering iron 13 is pressed at the center of the lid member 10. Therefore, by pressing the soldering iron 13 at an arbitrary position on the outer edge side rather than the center of the lid member 10, the influence on the joint portion when the lid member 10 returns to the state before elastic deformation after temporary fixing is suppressed. As a result, the lid member 10 is appropriately temporarily fixed to the holding member 2.

[0072] Also, in the temporary fixing step S130B, when heating the sealing material 11 of the lid member 10 adsorbed to the suction nozzle 12 with the soldering iron 13, the heat transmitted from the soldering iron 13 to the lid member 10 is transmitted not only to the sealing material 11 but also to the suction nozzle 12. The heat transmitted to the suction nozzle 12 is discharged to the outside without melting the sealing material 11. Therefore, the sealing material 11 is supplied with more heat by suppressing the heat transmitted to the suction nozzle 12 among the heat transmitted from the soldering iron 13. Therefore, it is desirable that the soldering iron 13 heats at a position as far as possible from the suction nozzle 12 in order to suppress the heat transmitted to the suction nozzle 12.

[0073] In the temporary fixing step S130B, the lid member 10 is heated by the soldering iron 13 at a portion overlapping the corner portion 11c of the sealing material 11 when viewed in the direction perpendicular to the upper surface of the lid member 10. Therefore, the heat of the soldering iron 13 is transmitted more efficiently to the thick portion of the sealing material 11. Therefore, in the temporary fixing step S130, the lid member 10 is temporarily fixed to the holding member 2 without reducing the melting speed of the thick corner portion 11c. Thereby, the gas generated from the bonding material 9 or the like located in the internal space S of the holding member 2 can be discharged without increasing the tact time.

[0074] [Other Embodiments] In the above-described embodiment, in the temporary fixing steps S130, S130A, and S130B, the lid member 10 is heated by the soldering iron 13 while being adsorbed to the suction nozzle 12. However, in the temporary fixing step, the lid member may be heated by the soldering iron while not being adsorbed to the suction nozzle.

[0075] When heating the lid member by the soldering iron while not being adsorbed to the suction nozzle, in the lid member transfer step, the lid member is held by the suction nozzle at a position having a slight gap from the bonding surface of the holding member.

[0076] Next, in the temporary fixing step, after separating the lid member adsorbed by the suction nozzle from the suction nozzle, it is brought into contact with the holding member. For example, the lid member adsorbed by the suction nozzle is separated from the suction nozzle by a soldering iron moving toward the holding member, and then pressed against the holding member by the soldering iron. Further, the lid member is heated while being pressed against the holding member by the soldering iron. That is, the lid member is heated by the soldering iron in a state where the suction nozzle is not in contact. Therefore, the heat transmitted from the soldering iron to the lid member is transmitted to the sealing material without escaping to the outside through the suction nozzle.

[0077] In the temporary fixing step configured in this way, the heat of the soldering iron is efficiently transmitted to the sealing material without escaping from the suction nozzle to the outside, so the melting speed of the sealing material is improved and the melting range of the sealing material is expanded. As a result, the tact time of the temporary fixing step is shortened. Furthermore, the temporary fixing strength between the lid member and the holding member by the sealing material is improved. Also, since heat is not discharged from the suction nozzle to the outside, when temporarily fixing a plurality of lid members continuously, a decrease in the temperature of the soldering iron is suppressed. Thereby, even when a plurality of lid members are continuously temporarily fixed by the soldering iron, the quality of the temporary fixing is stabilized. The temporary fixing step of heating with a soldering iron in a state where the lid member is not adsorbed by the suction nozzle is suitable when the suction nozzle is a metal suction nozzle with high thermal conductivity.

[0078] Also, in the above-described embodiment, in the step S110 of preparing the member with the sealing material, the lid member 10 provided with the sealing material 11 is prepared. However, as shown in FIG. 11, in the step S110 of preparing the member with the sealing material, the holding member 2 provided with the sealing material 11 may be prepared. In the holding member 2, in the lid member mounting step S120, the lid member 10 not provided with the sealing material 11 is mounted.

[0079] In addition, in the above-described embodiment, the holding member 2 is, for example, rectangular in plan view. The holding member 2 is configured to have, for example, a major side of 2.0 mm and a minor side of 1.6 mm. Further, the holding member 2 is configured to have, for example, a major side of 1.6 mm and a minor side of 1.2 mm. Further, the holding member 2 is configured to have, for example, a major side of 1.2 mm and a minor side of 1.0 mm.

[0080] The diameter (adsorption area) of the suction nozzle 12 and the size (contact area) of the contact portion of the soldering iron 13 are determined based on the size of the holding member 2 (lid member 10). For example, the diameter of the suction nozzle 12 with respect to the holding member 2 having a major side of 1.2 mm and a minor side of 1.0 mm is about 1 / 3 of the major side of the lid member 10 (see FIG. 12). For example, the size of the tip of the soldering iron 13 with respect to the holding member 2 having a major side of 1.2 mm and a minor side of 1.0 mm is about 1 / 2 of the major side of the lid member 10 in the major side direction of the lid member 10.

[0081] In addition, in the above-described embodiment, in the temporary fixing steps S130, S130A, and S130B, the lid member 10 is heated by the soldering iron 13 and the holding member 2 is heated by the holding member heating device 14. However, the temporary fixing step may be configured to heat only the lid member with a heating element.

[0082] In addition, in the above-described embodiment, in the temporary fixing steps S130, S130A, and S130B, the lid member 10 is heated by bringing the soldering iron 13 into direct contact with the lid member 10. However, in the temporary fixing step, it is not necessary to bring a heating element such as a soldering iron into direct contact when heating the lid member. The temporary fixing step may be configured to heat the lid member 10 and the holding member in a heating furnace, for example. Further, heating by far-infrared rays or a laser may also be used.

[0083] Also, in the above-described embodiments, in the temporary fixing steps S130, S130A, and S130B, the lid member 10 is heated by directly contacting the soldering iron 13 with the lid member 10. However, the temporary fixing step may be configured to directly heat the lid member while pressing the lid member with a heating element such as a soldering iron. In the temporary fixing step, the lid member is heated by the heating element while being pressed against the holding member by the heating element. Therefore, the thick portion located between the lid member and the holding member has an increased melting rate. Thereby, the gas generated from the bonding material or the like located in the internal space of the holding member can be discharged.

[0084] Also, in the above-described embodiments, in the temporary fixing step S130A, the soldering iron 13 is directly contacted with the lid member 10 in a state where the lid member 10 is adsorbed by the suction nozzle 12. However, the temporary fixing step may be configured to press the lid member while holding the lid member by a mounting means such as a suction nozzle. The lid member is heated by the heating element while being pressed against the holding member by the mounting means. Thereby, the gas generated from the bonding material or the like located in the internal space of the holding member can be discharged.

[0085] Also, in the above-described embodiments, in the temporary fixing step S130A, the soldering iron 13 is brought into contact with the lid member 10 in a state where the lid member 10 is adsorbed by the suction nozzle 12. However, the temporary fixing step may be configured to press the lid member 10 while holding the lid member 10 by a mounting means such as a suction nozzle, and pressing the lid member by the mounting means and a heating element such as a soldering iron. The lid member is heated by the heating element while being pressed by the mounting means and the heating element, respectively. At this time, the mounting means and the heating element are positioned so as to be symmetric with respect to a line sandwiching the center line in the longitudinal direction of the lid member. Therefore, in the temporary fixing step, the load per unit area applied to the sealing material can be made closer to uniform. Thereby, the variation in the joining state of the four corners can be suppressed.

[0086] In the above-described embodiment, in the temporary fixing step S130A, the soldering iron 13 is brought into contact with the lid member 10 while the lid member 10 is held by the suction nozzle 12. However, in the temporary fixing step, the lid member may be heated by the suction nozzle directly or indirectly heated by the heating element while being held by a mounting means such as a suction nozzle. Thereby, the gas generated from the bonding material or the like located in the internal space of the holding member can be discharged.

[0087] In the above-described embodiment, in the piezoelectric vibration device 1, the piezoelectric element 7 is located in the internal space S of the holding member 2. However, in the piezoelectric vibration device, the piezoelectric element and the electronic component element may be located in the internal space of the holding member. The electronic component element is an integrated circuit element including at least an oscillation circuit. Further, the electronic component element may be a vibrator with a built-in temperature sensor.

[0088] In the above-described embodiment, the sealing material 11 is a gold-tin alloy. However, the sealing material may be composed of a material that can seal the holding member with the lid member. The sealing material may be, for example, a metal brazing material, a thermoplastic resin, a glass material, or the like.

[0089] In the above-described embodiment, in the piezoelectric element sealing step S100, the lid member 10 is joined to the holding member 2 in a piece state. However, in the piezoelectric element sealing step, the lid member may be joined to each of the sheet-like members in which a large number of holding members are connected in a matrix.

[0090] The plurality of holding members 2 are integrally formed on a sheet-like member connected to each other. The size of the sheet-like member is configured to be the same regardless of the size of the holding member 2. That is, the number of holding members 2 included in the sheet-like member differs according to the size of the holding member 2. By configuring in this way, in the manufacturing method of the piezoelectric vibration device, even if the size of the holding member 2 is changed, it is not necessary to adjust the manufacturing apparatus of the piezoelectric vibration device according to the size of the holding member 2.

[0091] In addition, in the above-described embodiment, the piezoelectric vibration device 1 has the piezoelectric element 7 positioned within the internal space S of the holding member 2. However, the piezoelectric vibration device may be a so-called H-shaped piezoelectric vibration device having a bottom portion and frame-shaped side wall portions extending in directions perpendicular to the plane on two opposing planes of the bottom portion. In the H-shaped piezoelectric vibration device, the piezoelectric element is positioned on one plane of the bottom portion and inside one of the side wall portions. Further, in the H-shaped piezoelectric vibration device, an electronic component element is mounted on the other plane of the bottom portion and inside the other side wall portion. In the H-shaped piezoelectric vibration device, lid members are respectively joined to the tip portions of one side wall portion and the other side wall portion by a sealing material.

[0092] As described above, embodiments of the present invention have been explained. However, the above-described embodiments are merely examples for implementing the present invention. Therefore, without being limited to the above-described embodiments, it is possible to appropriately modify and implement the above-described embodiments within the scope not departing from the gist thereof.

Explanation of Reference Numerals

[0093] 1 Piezoelectric vibration device 2 Holding member 3 Bottom portion 4 Electrode pad 5 External terminal 6 Side wall portion 6a Bonding surface 7 Piezoelectric element 8 Electrode 9 Bonding material 10 Lid member 11 Sealing material 11a Longitudinal straight portion 11b Lateral straight portion 11c Corner portion (thick portion) 12 Suction nozzle 13 Soldering iron 14 Holding member heating device 15 Lid member heating device S Internal space As Lateral straight portion area Al Longitudinal straight portion area S100, S100A, S100B Piezoelectric Element Sealing Process S110 Member Preparation Process with Sealing Material S120 Cover Member Mounting Process S130, S130A, S130B Temporary Fixing Process S140 Sealing Process

Claims

1. A piezoelectric element, A holding member to which the piezoelectric element is joined, And at least a lid member that covers the piezoelectric element joined to the holding member, A method for manufacturing a piezoelectric vibration device in which a lid member is joined to a holding member to which a piezoelectric element is joined by a sealing material, When the piezoelectric element joined to the holding member is covered with the lid member, at least a part of the portion where one of the lid member and the holding member contacts the other is provided with the sealing material configured in a rectangular frame shape in a plan view, and preparing a member with a sealing material, wherein at least one corner portion of the sealing material has a thick portion that is thicker than other portions of the corner portion, and the lid member or the holding member having the thick portion is prepared; A lid member mounting step of mounting the lid member on the holding member to which the piezoelectric element is joined by bringing the thick portion of either the lid member or the holding member into contact with the other, A temporary fixing step of heating at least the lid member mounted on the holding member and melting at least a part of the thick portion to temporarily fix the lid member and the holding member, A sealing step of heating the temporarily fixed lid member and the holding member respectively in a vacuum or a nitrogen gas atmosphere and melting the sealing material including the thick portion to seal the lid member and the holding member, A method for manufacturing a piezoelectric vibration device.

2. A method for manufacturing a piezoelectric vibration device according to claim 1, In the temporary fixing step, heating the lid member by bringing a heating element into contact with a part of the lid member, A method for manufacturing a piezoelectric vibration device.

3. A method for manufacturing a piezoelectric vibration device according to claim 2, In the temporary fixing step, heating the lid member while holding the lid member by a mounting means, A method for manufacturing a piezoelectric vibration device.

4. The method for manufacturing a piezoelectric vibration device according to claim 2 or claim 3, wherein in the temporary fixing step, the lid member is pressed by the heating element; The method for manufacturing a piezoelectric vibration device.

5. The method for manufacturing a piezoelectric vibration device according to claim 4, wherein in the temporary fixing step, a portion of the lid member that overlaps at least a part of the sealing material in a plan view is pressed; The method for manufacturing a piezoelectric vibration device.

6. The method for manufacturing a piezoelectric vibration device according to claim 2, wherein in the temporary fixing step, the heating element is brought into contact with a position on an arbitrary outer edge side of the lid member rather than the center of the lid member in a plan view to heat the lid member; The method for manufacturing a piezoelectric vibration device.

7. The method for manufacturing a piezoelectric vibration device according to claim 1, wherein the sealing material is a gold-tin alloy; The method for manufacturing a piezoelectric vibration device.

8. The method for manufacturing a piezoelectric vibration device according to claim 1, wherein the sealing material contains a eutectic alloy and a non-eutectic alloy having a melting point higher than that of the eutectic alloy, and in the temporary fixing step, by heating the sealing material, the non-eutectic alloy is generated at at least one corner portion of the sealing material; The method for manufacturing a piezoelectric vibration device.

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