JP2016181880A - Piezoelectric oscillation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric oscillation device with a sandwich structure, in which the resonance of a package due to the oscillation leaking from a piezoelectric oscillation plate to the package is suppressed.SOLUTION: A crystal oscillator 101 includes: a crystal oscillation plate 2; a first sealing member 3 covering a first excitation electrode 221 of the crystal oscillation plate 2; and a second sealing member 4 covering a second excitation electrode 222 of the crystal oscillation plate 2. The first sealing member 3 and the crystal oscillation plate 2 are bonded and the second sealing member 4 and the crystal oscillation plate 2 are bonded, thereby forming a package 12. The package 12 is provided with an internal space 13 where an oscillation part 23 of the crystal oscillation plate 2 including the first excitation electrode 221 and the second excitation electrode 222 are sealed hermetically. The other main surface 312 of the first sealing member 3 is provided with a groove 39 that adjusts the specific frequency of the package 12.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a piezoelectric vibration device.

  In recent years, the operating frequency of various electronic devices has been increased, and the size of packages has been reduced (especially low profile). For this reason, piezoelectric vibration devices (for example, crystal resonators) are required to cope with higher frequencies and smaller packages with higher frequencies and smaller packages.

  In this type of piezoelectric vibration device, the casing is formed of a rectangular parallelepiped package. This package includes a first sealing member and a second sealing member made of glass or quartz, and a quartz crystal diaphragm made of quartz and having excitation electrodes formed on both main surfaces. Two sealing members are laminated and joined via a crystal diaphragm, and the excitation electrode of the crystal diaphragm disposed inside the package (internal space) is hermetically sealed (for example, Patent Document 1). Hereinafter, such a laminated form of piezoelectric vibration devices is referred to as a sandwich structure.

JP 2010-252051 A

  By the way, in the configuration in which the piezoelectric diaphragm is held on the holding member of the package using the conductive adhesive, the vibration leaking from the piezoelectric diaphragm to the holding member is absorbed by the conductive adhesive, so that the vibration of the piezoelectric diaphragm is It is hard to leak. However, in the piezoelectric vibration device having the sandwich structure as described above, since the first sealing member, the piezoelectric vibration plate, and the second sealing member are laminated and joined without using the conductive adhesive, the piezoelectric vibration The vibration of the board is easy to leak into the package. For this reason, there is a concern that the package resonates due to vibration leaking from the piezoelectric diaphragm to the package.

  The present invention has been made in consideration of the above-described situation, and an object of the present invention is to suppress package resonance caused by vibration leaking from a piezoelectric diaphragm to a package in a sandwich structure piezoelectric vibration device.

  In the present invention, means for solving the above-described problems are configured as follows. That is, the present invention provides a piezoelectric diaphragm in which a first excitation electrode is formed on one main surface of a substrate, and a second excitation electrode paired with the first excitation electrode is formed on the other main surface of the substrate; A first sealing member that covers the first excitation electrode of the piezoelectric diaphragm and a second sealing member that covers the second excitation electrode of the piezoelectric diaphragm are provided, and the first sealing member and the piezoelectric A diaphragm is joined, and the second sealing member and the piezoelectric diaphragm are joined to form a package, and the package includes the first excitation electrode and the second excitation electrode. In the piezoelectric vibration device provided with an internal space in which the vibration part of the piezoelectric diaphragm is hermetically sealed, the package is provided with an adjustment part for adjusting the natural frequency of the package.

  According to the above configuration, by adjusting the natural frequency of the package by the adjustment unit, the natural frequency of the package and the frequency of vibration leaking from the vibration unit of the piezoelectric diaphragm to the package can be easily made different. Thereby, the resonance of the package due to the vibration leaking from the vibrating portion of the piezoelectric diaphragm to the package can be suppressed.

  In the above configuration, the piezoelectric diaphragm includes the vibrating portion formed in a substantially rectangular shape, an outer frame portion that surrounds an outer periphery of the vibrating portion, and a connecting portion that connects the vibrating portion and the outer frame portion. The vibrating portion, the connecting portion, and the outer frame portion may be provided integrally.

  Here, in the configuration in which the piezoelectric diaphragm is held on the holding member (base or the like) of the package using the conductive adhesive, vibration leaking from the piezoelectric diaphragm to the holding member is absorbed by the conductive adhesive. The influence of leaking vibration is relatively small. However, when a piezoelectric diaphragm having a configuration in which the vibrating portion is held by the connecting portion without using a conductive adhesive as in this configuration, the vibrating portion of the piezoelectric vibrating plate, the connecting portion, and the outer frame portion are Since they are integrally provided, vibration is likely to leak from the vibrating portion of the piezoelectric diaphragm to the outer frame portion via the connecting portion. Therefore, in this configuration, by adjusting the natural frequency of the package with the adjusting unit, the natural frequency of the package and the frequency of the vibration leaking from the vibrating unit of the piezoelectric diaphragm to the package are made different from each other. The resonance of the package due to the vibration leaking from the vibration portion of the plate to the outer frame portion via the connecting portion is suppressed.

  The said structure WHEREIN: The said adjustment part may be provided in the part which faces the said internal space of a said 1st sealing member. Moreover, the said adjustment part may be provided also in the part which faces the said internal space of a said 2nd sealing member.

  Here, the adjustment part is provided in a portion (one main surface side of the first sealing member or the other main surface side of the second sealing member) that does not face the internal space of the first sealing member or the second sealing member. If so, the following points are concerned. When the package comes into contact with the outside, there is a possibility that the shape, dimensions, etc. of the adjusting portion may change, and the adjustment of the natural frequency of the package accompanying this is necessary. In addition, wiring for connection with external elements (circuit board, mounted components, etc.) is provided on one main surface side of the first sealing member and on the other main surface of the second sealing member. Due to the presence of the portion, the degree of freedom of wiring is restricted, and the area of the wiring may be reduced.

  On the other hand, in this structure, since the adjustment part is provided in the part which faces the internal space of a 1st, 2nd sealing member, an adjustment part is protected by a package. As a result, changes in the shape, dimensions, etc. of the adjustment portion due to the package 12 coming into contact with the outside are prevented, and adjustment of the natural frequency of the package accompanying changes in the shape, dimensions, etc. of the adjustment portion is not necessary. In addition, on one main surface of the first sealing member and the other main surface of the second sealing member, the degree of freedom of wiring for connection to external elements can be increased, and the area necessary for wiring can be easily secured. can do.

  The said structure WHEREIN: A groove | channel may be sufficient as the said adjustment part.

  According to the above configuration, the natural frequency of the package can be easily adjusted by adjusting the number, shape, dimensions, and the like of the grooves, resulting from vibration leaking from the vibrating portion of the piezoelectric diaphragm to the package. The resonance of the package can be effectively suppressed.

  According to the present invention, by adjusting the natural frequency of the package by the adjustment unit, the natural frequency of the package and the frequency of vibration leaking from the vibration unit of the piezoelectric diaphragm to the package can be easily made different. Thereby, the resonance of the package due to the vibration leaking from the vibrating portion of the piezoelectric diaphragm to the package can be suppressed.

FIG. 1 is a schematic configuration diagram showing each configuration of the crystal resonator according to the present embodiment. FIG. 2 is a schematic plan view of the first sealing member of the crystal resonator according to the present embodiment. FIG. 3 is a schematic back view of the first sealing member of the crystal resonator according to the present embodiment. FIG. 4 is a schematic plan view of the crystal diaphragm of the crystal resonator according to the present embodiment. FIG. 5 is a schematic back view of the crystal diaphragm of the crystal resonator according to the present embodiment. FIG. 6 is a schematic plan view of the second sealing member of the crystal resonator according to the present embodiment. FIG. 7 is a schematic back view of the second sealing member of the crystal resonator according to the present embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, a case where the present invention is applied to a crystal resonator as a piezoelectric vibration device that performs piezoelectric vibration will be described.

  In the crystal resonator 101 according to the present embodiment, as shown in FIG. 1, a crystal diaphragm 2 (a piezoelectric diaphragm in the present invention) and a first excitation electrode 221 (see FIG. 4) of the crystal diaphragm 2 are provided. A first sealing member 3 that hermetically seals the first excitation electrode 221 formed on one main surface 211 of the crystal diaphragm 2 and the other main surface 212 of the crystal diaphragm 2 A second sealing member 4 that covers the second excitation electrode 222 (see FIG. 5) and hermetically seals the second excitation electrode 222 formed in a pair with the first excitation electrode 221 is provided. In the crystal resonator 101, the crystal diaphragm 2 and the first sealing member 3 are joined, and the crystal diaphragm 2 and the second sealing member 4 are joined to form a sandwich-structured package 12.

  And the 1st sealing member 3 and the 2nd sealing member 4 are joined via the crystal diaphragm 2, and the internal space 13 of the package 12 is formed, In this internal space 13 of this package 12, crystal | crystallization The vibration part 23 including the first excitation electrode 221 and the second excitation electrode 222 formed on both main surfaces 211 and 212 of the diaphragm 2 is hermetically sealed. The crystal unit 101 according to the present embodiment has a package size of, for example, 1.0 × 0.8 mm, and is intended to be reduced in size and height. In addition, with the miniaturization, in this package 12, the electrodes are connected using the through holes (first to ninth through holes) without forming a castellation.

  Next, each configuration of the above-described crystal resonator 101 will be described with reference to FIGS. Here, each member configured as a single unit in which the crystal diaphragm 2, the first sealing member 3, and the second sealing member 4 are not joined will be described.

  As shown in FIGS. 4 and 5, the quartz diaphragm 2 is made of quartz which is a piezoelectric material, and both main surfaces (one main surface 211 and the other main surface 212) are formed as flat smooth surfaces (mirror finish). Yes.

  In addition, a pair of (paired) excitation electrodes (a first excitation electrode 221 and a second excitation electrode 222) are formed on both main surfaces 211 and 212 (one main surface 211 and another main surface 212) of the crystal diaphragm 2. ing. The two main surfaces 211 and 212 are formed with two notches 24 (penetrating shape) so as to surround the pair of first excitation electrodes 221 and second excitation electrodes 222, thereby constituting the vibration part 23. . The cutout 24 includes a concave body 241 in plan view (three rectangles in plan view, each of which is formed by extending two rectangles from both ends of one rectangle in plan view in a direction perpendicular to the longitudinal direction of the rectangle). A planar view body) and a planar view rectangular body 242. As described above, in the present embodiment, the quartz crystal diaphragm 2 includes the vibrating portion 23 formed in a substantially rectangular shape, the outer frame portion 214 that surrounds the outer periphery of the vibrating portion 23, and the vibrating portion 23 and the outer frame portion 214. It has the connection part 213 to connect, and it has the structure by which the vibration part 23, the connection part 213, and the outer frame part 214 were provided integrally.

  Then, the first excitation electrode 221 and the second excitation electrode 222 are connected to the external electrode terminals (one external electrode terminal 431, others) on the connecting portion 213 provided between the concave body 241 in plan view and the rectangular body 242 in plan view. An extraction electrode (first extraction electrode 223, second extraction electrode 224) for extraction to the external electrode terminal 432) is provided. The first excitation electrode 221 and the first extraction electrode 223 are formed by stacking a base PVD film formed by physical vapor deposition on one main surface 211 and a physical vapor deposition on the base PVD film. Electrode PVD film. The second excitation electrode 222 and the second extraction electrode 224 are formed by stacking a base PVD film formed by physical vapor deposition on the other main surface 212 and a physical vapor deposition on the base PVD film. Electrode PVD film.

  Both main surfaces 211 and 212 of the outer frame portion 214 are provided with vibration-side sealing portions 25 for joining the first sealing member 3 and the second sealing member 4 so as to surround the vibration portion 23, respectively. ing. A vibration side first bonding pattern 251 for bonding to the first sealing member 3 is formed on the vibration side sealing portion 25 of the one main surface 211 of the crystal diaphragm 2. A vibration-side second bonding pattern 252 for bonding to the second sealing member 4 is formed on the vibration-side sealing portion 25 of the other main surface 212 of the crystal diaphragm 2. The vibration side first bonding pattern 251 and the vibration side second bonding pattern 252 are formed in an annular shape in plan view. The internal space 13 is formed inside (inside) the vibration side first bonding pattern 251 and the vibration side second bonding pattern 252 in a plan view. Here, the inside of the internal space 13 means the inside of the inner peripheral surface of the bonding material 11 strictly without including the bonding material 11 described later. The pair of first excitation electrode 221 and second excitation electrode 222 of the crystal diaphragm 2 are not electrically connected to the vibration side first bonding pattern 251 and the vibration side second bonding pattern 252.

  The vibration-side first bonding pattern 251 includes a base PVD film 2511 formed by physical vapor deposition on one main surface 211 and an electrode PVD formed by physical vapor deposition on the base PVD film 2511 and stacked. A film 2512. The vibration-side second bonding pattern 252 includes a base PVD film 2521 formed by physical vapor deposition on the other main surface 212 and an electrode PVD formed by physical vapor deposition on the base PVD film 2521 and stacked. A film 2522. That is, the vibration side first bonding pattern 251 and the vibration side second bonding pattern 252 have the same configuration, and a plurality of layers are stacked on the vibration side sealing portion 25 of both main surfaces 211 and 212, A Ti layer (or Cr layer) and an Au layer are formed by vapor deposition from the lowermost layer side. Thus, in the vibration side first bonding pattern 251 and the vibration side second bonding pattern 252, the underlying PVD films 2511 and 2521 are made of a single material (Ti (or Cr)), and the electrode PVD films 2512 and 2522 are formed. The electrode PVD films 2512 and 2522 are made of a single material (Au) and are thicker than the underlying PVD films 2511 and 2521. Further, the first excitation electrode 221 and the vibration-side first bonding pattern 251 formed on the one main surface 211 of the crystal diaphragm 2 have the same thickness, and the first excitation electrode 221 and the vibration-side first bonding pattern 251 have the same thickness. The second excitation electrode 222 and the vibration side second bonding pattern 252 formed on the other major surface 212 of the quartz crystal plate 2 have the same thickness, and the second excitation electrode is made of the same metal. The surfaces (main surfaces) of 222 and the vibration side second bonding pattern 252 are made of the same metal. The vibration side first bonding pattern 251 and the vibration side second bonding pattern 252 are non-Sn patterns.

  Here, the first excitation electrode 221, the first extraction electrode 223, and the vibration-side first bonding pattern 251 can have the same configuration, and in this case, the first excitation electrode 221 and the first extraction electrode 223 are the same process. And the vibration side 1st joining pattern 251 can be formed in a lump. Similarly, the second excitation electrode 222, the second extraction electrode 224, and the vibration-side second bonding pattern 252 can have the same configuration. In this case, the second excitation electrode 222, the second extraction electrode 224 are performed in the same process. And the vibration side 2nd joining pattern 252 can be formed collectively. Specifically, the underlying PVD film or the electrode PVD film is formed by a PVD method such as vacuum deposition, sputtering, ion plating, MBE, or laser ablation (for example, a film forming method for patterning in processing such as photolithography). Thus, the film formation can be performed at one time, the number of manufacturing steps can be reduced, and the cost can be reduced.

  In addition, as shown in FIGS. 4 and 5, the crystal diaphragm 2 has three through holes (first to third through holes 267 to 269) penetrating between the one main surface 211 and the other main surface 212. Is formed. The first through hole 267 is connected to the fourth through hole 347 of the first sealing member 3 and the eighth through hole 447 of the second sealing member 4. The second through hole 268 is connected to the sixth through hole 349 of the first sealing member 3 and the ninth through hole 448 of the second sealing member 4. The third through hole 269 is connected to the second extraction electrode 224 extracted from the second excitation electrode 222 and the seventh through hole 350 of the first sealing member 3 through the bonding material 14 described later. The first through hole 267 and the second through hole 268 are respectively located at both ends in the longitudinal direction of the crystal diaphragm 2 in plan view.

  In the first to third through holes 267 to 269, as shown in FIGS. 1, 4, and 5, through electrodes 71 for conducting the electrodes formed on the one main surface 211 and the other main surface 212 are provided. It is formed along the inner wall surface of each of the first to third through holes 267 to 269. The central portion of each of the first to third through holes 267 to 269 becomes a hollow through portion 72 penetrating between the one main surface 211 and the other main surface 212. A connection bonding pattern 73 is formed on the outer periphery of each of the first to third through holes 267 to 269. The connection bonding pattern 73 is provided on both main surfaces (one main surface 211 and the other main surface 212) of the crystal diaphragm 2. The connection bonding pattern 73 has the same configuration as the vibration side first bonding pattern 251 and the vibration side second bonding pattern 252, and is formed by the same process as the vibration side first bonding pattern 251 and vibration side second bonding pattern 252. can do. Specifically, the connection bonding pattern 73 includes a base PVD film formed by physical vapor deposition on both main surfaces (one main surface 211 and another main surface 212) of the quartz crystal plate 2, and the base It consists of an electrode PVD film formed by physical vapor deposition on the PVD film. The connection pattern 73 for connection of the third through-hole 269 formed on the one main surface 211 of the crystal diaphragm 2 extends along the direction of the arrow A1 in FIG. 4, and the vibration-side first connection pattern 251 and the cutout portion. 24. The connection pattern 73 for connection of the third through-hole 269 formed on the other main surface 212 of the crystal diaphragm 2 is formed integrally with the second extraction electrode 224 extracted from the second excitation electrode 222.

  In the crystal unit 101, the first through hole 267 and the second through hole 268 are formed outside the inner space 13 (outside the outer peripheral surface of the bonding material 11) in plan view. On the other hand, the third through hole 269 is formed inward of the internal space 13 (inside the inner peripheral surface of the bonding material 11) in plan view. The first to third through holes 267 to 269 are not electrically connected to the vibration side first bonding pattern 251 and the vibration side second bonding pattern 252.

The first sealing member 3 is made of a material having a bending rigidity (secondary moment of section × Young's modulus) of 1000 [N · mm ² ] or less. Specifically, as shown in FIGS. 2 and 3, the first sealing member 3 is a rectangular parallelepiped substrate formed from a single glass wafer, and the other main surface 312 ( The surface to be bonded to the crystal diaphragm 2 is formed as a flat smooth surface (mirror finish).

  The other main surface 312 of the first sealing member 3 is provided with a sealing-side first sealing portion 32 for joining to the crystal diaphragm 2. A sealing-side first bonding pattern 321 for bonding to the crystal diaphragm 2 is formed on the sealing-side first sealing portion 32 of the first sealing member 3. The sealing side first bonding pattern 321 is formed in an annular shape in plan view. The sealing side first bonding pattern 321 has the same width at all positions on the sealing side first sealing portion 32 of the first sealing member 3.

  The sealing-side first bonding pattern 321 is formed by stacking a base PVD film 3211 formed by physical vapor deposition on the first sealing member 3 and a physical vapor deposition on the base PVD film 3211. Electrode PVD film 3212 formed. In this embodiment, Ti (or Cr) is used for the base PVD film 3211 and Au is used for the electrode PVD film 3212. Moreover, the sealing side 1st joining pattern 321 is a non-Sn pattern. Specifically, the sealing side first bonding pattern 321 is configured by laminating a plurality of layers on the sealing side first sealing portion 32 of the other main surface 312, and the Ti layer (or from the lowermost layer side). Cr layer) and Au layer are formed by vapor deposition.

  A first terminal 37 and a second terminal 38 are provided on one main surface 311 of the first sealing member 3 (an outer main surface not facing the crystal diaphragm 2). The first terminal 37 is provided so as to connect the fourth through hole 347 and the fifth through hole 348, and the second terminal 38 is provided so as to connect the sixth through hole 349 and the seventh through hole 350. Yes. The first terminal 37 and the second terminal 38 are formed by physical vapor deposition on the underlying PVD films 3711 and 3811 formed by physical vapor deposition on one main surface 311 and the underlying PVD films 3711 and 3811. The electrode PVD films 3712 and 3812 are stacked. In the present embodiment, the first terminal 37 and the second terminal 38 are located at both ends in the longitudinal direction of the main surface 311 of the first sealing member 3 in the plan view.

  As shown in FIGS. 1 and 3, four grooves 39 extending in a straight line are formed on the other main surface 312 of the first sealing member 3. The four grooves 39 are provided in parallel with each other at a predetermined interval. The four grooves 39 extend parallel to the short side direction of the first sealing member 3. The four grooves 39 are provided in a portion facing the internal space 13 of the first sealing member 3. The groove 39 is preferably formed on the other main surface 312 of the first sealing member 3 by wet etching or dry etching. The groove 39 can be formed on the other main surface 312 of the first sealing member 3 by means such as laser processing.

  As shown in FIGS. 1 to 3, the first sealing member 3 has four through holes (fourth to seventh through holes 347 to 350) penetrating between the one main surface 311 and the other main surface 312. Is formed. The fourth through hole 347 is connected to the first terminal 37 and the first through hole 267 of the crystal diaphragm 2. The fifth through hole 348 is connected to the first extraction electrode 223 extracted from the first terminal 37 and the first excitation electrode 221 of the quartz crystal diaphragm 2. The sixth through hole 349 is connected to the second terminal 38 and the second through hole 268 of the crystal diaphragm 2. The seventh through hole 350 is connected to the second terminal 38 and the third through hole 269 of the crystal diaphragm 2. The fourth through hole 347 and the sixth through hole 349 are located at both ends in the longitudinal direction of the first sealing member 3 in the plan view.

  In the fourth to seventh through holes 347 to 350, as shown in FIGS. 1 to 3, there are provided through electrodes 71 for conducting the electrodes formed on the one main surface 311 and the other main surface 312. -Seventh through-holes 347-350 are formed along the inner wall surfaces. The central portion of each of the fourth to seventh through holes 347 to 350 is a hollow through portion 72 that penetrates between one main surface 311 and the other main surface 312. A connection bonding pattern 73 is formed on the outer periphery of each of the fourth to seventh through holes 347 to 350. The connection bonding pattern 73 is provided on the other main surface 312 of the first sealing member 3. The connection bonding pattern 73 has the same configuration as the sealing-side first bonding pattern 321 and can be formed by the same process as the sealing-side first bonding pattern 321. Specifically, the connection bonding pattern 73 includes a base PVD film formed by physical vapor deposition on the other main surface 312 of the first sealing member 3, and a physical vapor phase on the base PVD film. It consists of an electrode PVD film that is grown and laminated. The connection pattern 73 for connection of the seventh through hole 350 extends along the direction of the arrow A1 in FIG.

  In the crystal unit 101, the fourth through hole 347 and the sixth through hole 349 are formed outside the internal space 13 in plan view. On the other hand, the fifth through hole 348 and the seventh through hole 350 are formed inside the internal space 13 in a plan view. The fourth to seventh through holes 347 to 350 are not electrically connected to the sealing-side first bonding pattern 321. In addition, the first terminal 37 and the second terminal 38 are not electrically connected to the sealing-side first bonding pattern 321. The first terminal 37 and the second terminal 38 are provided from the inner side to the outer side of the bonding material 11 in plan view. That is, the first terminal 37 and the second terminal 38 are provided so as to straddle the bonding material 11 in a plan view (intersect the bonding material 11).

For the second sealing member 4, a material having a bending rigidity (secondary moment of section × Young's modulus) of 1000 [N · mm ² ] or less is used. Specifically, as shown in FIG. 6, the second sealing member 4 is a rectangular parallelepiped substrate formed from a single glass wafer, and one main surface 411 (quartz crystal vibration) of the second sealing member 4 The surface joined to the plate 2 is formed as a flat smooth surface (mirror finish).

  The main surface 411 of the second sealing member 4 is provided with a sealing-side second sealing portion 42 for joining to the crystal diaphragm 2. The sealing-side second sealing part 42 is formed with a sealing-side second bonding pattern 421 for bonding to the crystal vibrating plate 2. The sealing-side second bonding pattern 421 is formed in an annular shape in plan view. The sealing side second bonding pattern 421 has the same width at all positions on the sealing side second sealing portion 42 of the second sealing member 4.

  The sealing-side second bonding pattern 421 is formed by stacking a base PVD film 4211 formed by physical vapor deposition on the second sealing member 4 and a physical vapor deposition on the base PVD film 4211. The electrode PVD film 4212 is formed. Note that in this embodiment, Ti (or Cr) is used for the base PVD film 4211 and Au is used for the electrode PVD film 4212. Further, the sealing-side second bonding pattern 421 is a non-Sn pattern. Specifically, the sealing-side second bonding pattern 421 is configured by laminating a plurality of layers on the sealing-side second sealing portion 42 of the other main surface 412, and Ti layer (or from the lowermost layer side) Cr layer) and Au layer are formed by vapor deposition.

  In addition, a pair of external electrode terminals (one external electrode terminal 431, etc.) electrically connected to the outside are provided on the other main surface 412 of the second sealing member 4 (an outer main surface not facing the crystal diaphragm 2). An external electrode terminal 432) is provided. As shown in FIGS. 1 and 7, the one external electrode terminal 431 and the other external electrode terminal 432 are respectively located at both ends in the longitudinal direction of the other main surface 412 of the second sealing member 4 in the plan view. The pair of external electrode terminals (one external electrode terminal 431 and the other external electrode terminal 432) are formed of a base PVD film 4311 and 4321 formed by physical vapor deposition on the other main surface 412, and a base PVD film 4311, The electrode PVD films 4312 and 4322 are formed by physical vapor deposition on 4321 and are stacked. The one external electrode terminal 431 and the other external electrode terminal 432 occupy one-third or more of the other main surface 412 of the second sealing member 4.

  As shown in FIGS. 1, 6, and 7, the second sealing member 4 includes two through-holes (eighth through-hole 447 and ninth through-hole) that pass between one main surface 411 and the other main surface 412. 448) is formed. The eighth through hole 447 is connected to the one external electrode terminal 431 and the first through hole 267 of the crystal diaphragm 2. The ninth through hole 448 is connected to the other external electrode terminal 432 and the second through hole 268 of the crystal diaphragm 2. The eighth through hole 447 and the ninth through hole 448 are respectively located at both ends in the longitudinal direction of the second sealing member 4 in the plan view.

  In the eighth through hole 447 and the ninth through hole 448, as shown in FIGS. 1, 6 and 7, a through electrode 71 for conducting the electrodes formed on the one main surface 411 and the other main surface 412 is provided. , And are formed along inner wall surfaces of the eighth through hole 447 and the ninth through hole 448, respectively. The central portions of the eighth through hole 447 and the ninth through hole 448 become a hollow through portion 72 that penetrates between one main surface 411 and the other main surface 412. A connecting joint pattern 73 is formed around the outer periphery of each of the eighth through hole 447 and the ninth through hole 448. Further, on one main surface 411, a connection bonding pattern 73 provided on the outer periphery of the third through-hole 269 of the crystal diaphragm 2 is bonded to the inner side of the sealing-side second bonding pattern 421 in a plan view. A connection bonding pattern 73 is formed. The connection bonding pattern 73 is provided on one main surface 411 of the second sealing member 4. The connection bonding pattern 73 has the same configuration as the sealing-side second bonding pattern 421 and can be formed by the same process as the sealing-side second bonding pattern 421. Specifically, the connection bonding pattern 73 includes a base PVD film formed by physical vapor deposition on one main surface 411 of the second sealing member 4, and a physical vapor phase on the base PVD film. It consists of an electrode PVD film that is grown and laminated.

  In the crystal unit 101, the eighth through hole 447 and the ninth through hole 448 are formed outside the internal space 13 in plan view. The eighth through hole 447 and the ninth through hole 448 are not electrically connected to the sealing-side second bonding pattern 421. Also, the one external electrode terminal 431 and the other external electrode terminal 432 are not electrically connected to the sealing-side second bonding pattern 421.

  In the quartz crystal resonator 101 having the above-described configuration, the quartz-crystal diaphragm 2 and the first sealing member 3 are connected to the vibration-side first bonding pattern 251 without using a dedicated bonding material such as an adhesive as in the prior art. In addition, diffusion bonding is performed in a state where the sealing-side first bonding pattern 321 is overlapped, and the crystal diaphragm 2 and the second sealing member 4 overlap the vibration-side second bonding pattern 252 and the sealing-side second bonding pattern 421. The sandwiched package 12 shown in FIG. 1 is manufactured by diffusion bonding in the combined state. Thereby, the internal space 13 of the package 12, that is, the accommodation space of the vibration part 23 is hermetically sealed. The vibration side first bonding pattern 251 and the sealing side first bonding pattern 321 itself become the bonding material 11 generated after diffusion bonding, and the vibration side second bonding pattern 252 and the sealing side second bonding pattern 421 itself diffuse. It becomes the joining material 11 produced | generated after joining. The bonding material 11 is formed in an annular shape in plan view.

  At this time, diffusion bonding is performed in a state where the outer peripheral connection bonding patterns 73 of the first to ninth through holes 267 to 269, 347 to 350, 447, and 448 are also overlapped. Specifically, the connection bonding patterns 73 of the first through hole 267 and the fourth through hole 347 are diffusion bonded. The connection pattern 73 for connection of the first through hole 267 and the eighth through hole 447 is diffusion bonded. Further, the connection bonding patterns 73 of the second through hole 268 and the sixth through hole 349 are diffusion bonded. The connection pattern 73 for connection of the second through hole 268 and the ninth through hole 448 is diffusion bonded. Further, the connection bonding patterns 73 of the third through hole 269 and the seventh through hole 350 are diffusion bonded. The connection bonding pattern 73 of the third through hole 269 is diffusion bonded in a state of being superimposed on the connection bonding pattern 73 provided on the one main surface 411 of the second sealing member 4. Each of the connection bonding patterns 73 is a bonding material 14 generated after diffusion bonding. The connection bonding pattern 73 of the fifth through-hole 348 is diffusion bonded in a state where it is overlapped with the first extraction electrode 223 extracted from the first excitation electrode 221 of the crystal diaphragm 2. And the joining pattern 73 for connection and the 1st extraction electrode 223 itself become the joining material 14 produced | generated after a diffusion joining. These bonding materials 14 formed by diffusion bonding serve to conduct the through electrodes 71 of the through holes and to hermetically seal the bonding portions. In FIG. 1, the bonding material 14 provided outside the sealing bonding material 11 in a plan view is indicated by a solid line, and the bonding material 14 provided inside the bonding material 11 is indicated by a broken line. ing.

  In this embodiment, diffusion bonding is performed at room temperature. The normal temperature here means 5 ° C to 35 ° C. Although this room temperature diffusion bonding has the following effects (suppression of gas generation and good bonding), this is a preferred example having a value lower than 183 ° C., which is the melting point of eutectic solder. However, only room temperature diffusion bonding does not have the effects described below, and it is sufficient that diffusion bonding is performed at a temperature of normal temperature or higher and lower than 230 ° C. In particular, when diffusion bonding is performed at a temperature of 200 ° C. or higher and lower than 230 ° C., the melting point of the Pb-free solder is lower than 230 ° C., and the Au recrystallization temperature (200 ° C.) or higher is reached. The stable region can be stabilized. Further, in the present embodiment, since a dedicated bonding material such as Au—Sn is not used, there is no generation of a gas such as a plating gas, a binder gas, and a metal gas. Therefore, the recrystallization temperature can be made higher than Au.

  In the package 12 manufactured by diffusion bonding, the first sealing member 3 and the crystal diaphragm 2 have a gap of 1.00 μm or less, and the second sealing member 4 and the crystal diaphragm 2 are It has a gap of 1.00 μm or less. That is, the thickness of the bonding material 11 between the first sealing member 3 and the crystal vibrating plate 2 is 1.00 μm or less, and the bonding material 11 between the second sealing member 4 and the crystal vibrating plate 2 The thickness is 1.00 μm or less (specifically, 0.15 μm to 1.00 μm in the Au—Au bonding of the present embodiment). For comparison, a conventional metal paste sealing material using Sn has a thickness of 5 μm to 20 μm.

  The thickness of the bonding pattern in which the sealing-side first bonding pattern 321 and the vibration-side first bonding pattern 251 are diffusion-bonded is such that the sealing-side second bonding pattern 421 and the vibration-side second bonding pattern 252 are diffusion-bonded. The thickness of the bonded pattern is the same as the thickness of the external electrode terminal (one external electrode terminal 431 and the other external electrode terminal 432) electrically connected to the outside.

  In the present embodiment, a groove 39 is provided on the other main surface 312 of the first sealing member 3. The groove 39 is an adjustment unit that adjusts the natural frequency of the package 12 in the crystal unit 101. The natural frequency of the package 12 can be easily adjusted by adjusting the number, shape, dimensions, and the like of the grooves 39.

  Therefore, by adjusting the natural frequency of the package 12 by the groove 39, the natural frequency of the package 12 and the frequency of vibration leaking from the vibration part 23 of the crystal diaphragm 2 to the package 12 can be easily made different. . Thereby, the resonance of the package 12 caused by the vibration leaking from the vibration part 23 of the crystal diaphragm 2 to the package 12 can be suppressed.

  Here, in the present embodiment, the first sealing member 3, the quartz crystal vibration plate 2, and the second sealing member 4 are laminated and joined without using the conductive adhesive. Compared with the case of using, the vibration of the vibration part 23 of the crystal diaphragm 2 is more likely to leak into the package 12. For this reason, there is a concern that the package 12 resonates due to vibration leaking from the vibrating portion 23 of the quartz crystal plate 2 to the package 12. However, in the present embodiment, the natural frequency of the package 12 is adjusted by the groove 39 as the adjusting unit, so that the natural frequency of the package 12 and the vibration leaking from the vibrating unit 23 of the crystal diaphragm 2 to the package 12 can be reduced. By making the frequency different, the resonance of the package due to the vibration leaking from the vibration part 23 of the crystal diaphragm 2 to the outer frame part 214 via the connecting part 213 is suppressed.

  Here, when the groove | channel is provided in the part which does not face the internal space 13 of the 1st sealing member 3, specifically, the one main surface 311 side of the 1st sealing member 3, the next point is Concerned. When the package 12 comes into contact with the outside, the shape, dimensions, and the like of the groove 39 may change, and it is necessary to adjust the natural frequency of the package 12 accordingly. In addition, the main surface 311 of the first sealing member 3 may be provided with wiring for connection with an external element (circuit board, mounted component, etc.). There is a possibility that the degree of freedom is restricted and the area of the wiring is reduced.

  On the other hand, in the present embodiment, since the groove 39 is provided in the portion of the other main surface 312 of the first sealing member 3 facing the internal space 13, the groove 39 is protected by the package 12. This prevents changes in the shape and dimensions of the groove 39 due to the package 12 coming into contact with the outside, and adjustment of the natural frequency of the package 12 accompanying changes in the shape and dimensions of the groove 39 becomes unnecessary. Moreover, in the 1st main surface 311 of the 1st sealing member 3, the freedom degree of the wiring for a connection with an external element can be raised, and the area required for wiring can be ensured easily.

  In the present embodiment, the number, shape, dimensions, and the like of the grooves 39 can be changed as appropriate. Further, in place of the other main surface 312 of the first sealing member 3, a groove may be provided in a portion facing the internal space 13 of the one main surface 411 of the second sealing member 4. Or you may provide a groove | channel in the part which faces the internal space 13 of both the other main surface 312 of the 1st sealing member 3, and the one main surface 411 of the 2nd sealing member 4. FIG.

  In the present embodiment, the groove 39 is used as an adjustment unit that adjusts the natural frequency of the package 12, but other than the groove such as a bottomed hole may be used. Moreover, as such an adjustment part, the protrusion and level | step difference (step part) which were formed in at least one of the 1st sealing member 3 and the 2nd sealing member 4, for example, the 1st sealing member 3 and the 2nd sealing A weight fixed to at least one of the members 4 can be employed. Alternatively, the natural frequency of the package 12 may be adjusted by a mass load such as a vapor deposition film formed on at least one of the first sealing member 3 and the second sealing member 4, and the first sealing member The natural frequency of the package 12 may be adjusted by changing the thickness of at least one of 3 and the second sealing member 4.

  Moreover, in this Embodiment, although glass is used for the 1st sealing member 3 and the 2nd sealing member 4, it is not limited to this, You may use a crystal.

  In this embodiment, quartz is used for the piezoelectric diaphragm, but the present invention is not limited to this, and other materials may be used as long as they are piezoelectric materials, such as lithium niobate, lithium tantalate, etc. It may be.

  In the present embodiment, Ti (or Cr) and Au are used as the bonding material 11. However, the present invention is not limited to this, and the bonding material 11 may be composed of, for example, Ni and Au. .

  In the above embodiment, the piezoelectric vibration device is a crystal resonator, but the present invention can also be applied to a piezoelectric vibration device (for example, a crystal oscillator) other than the crystal resonator.

  The present invention is suitable for a crystal vibration device (a crystal resonator, a crystal oscillator, or the like) using quartz as a material for a substrate of a piezoelectric vibration plate.

DESCRIPTION OF SYMBOLS 101 Crystal resonator 12 Package 13 Internal space 2 Crystal diaphragm 213 Connection part 214 Outer frame part 221 1st excitation electrode 222 2nd excitation electrode 23 Vibration part 3 1st sealing member 39 Groove 4 2nd sealing member

Claims (5)

A piezoelectric diaphragm in which a first excitation electrode is formed on one main surface of the substrate and a second excitation electrode paired with the first excitation electrode is formed on the other main surface of the substrate;
A first sealing member that covers the first excitation electrode of the piezoelectric diaphragm;
A second sealing member that covers the second excitation electrode of the piezoelectric diaphragm,
A package is formed by joining the first sealing member and the piezoelectric diaphragm, and joining the second sealing member and the piezoelectric diaphragm, and the package includes the first excitation electrode. And a piezoelectric vibrating device provided with an internal space hermetically sealed with a vibrating portion of the piezoelectric diaphragm including the second excitation electrode,
The piezoelectric vibration device according to claim 1, wherein the package is provided with an adjustment unit that adjusts the natural frequency of the package. The piezoelectric vibration device according to claim 1,
The piezoelectric diaphragm is
The vibrating portion formed in a substantially rectangular shape;
An outer frame portion surrounding the outer periphery of the vibrating portion;
A connecting portion that connects the vibrating portion and the outer frame portion;
The piezoelectric vibration device, wherein the vibration part, the connection part, and the outer frame part are provided integrally. The piezoelectric vibration device according to claim 1 or 2,
The piezoelectric vibration device according to claim 1, wherein the adjustment portion is provided in a portion of the first sealing member facing the internal space. The piezoelectric vibration device according to claim 3,
The adjustment unit is also provided in a portion of the second sealing member that faces the internal space. The piezoelectric vibration device according to any one of claims 1 to 4,
The piezoelectric vibration device according to claim 1, wherein the adjustment portion is a groove.

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