JP2017011552A - Piezoelectric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric device in which the risk of occurring an unintended stress in a piezoelectric vibration element can be reduced.SOLUTION: A transducer 1 has an element mounting member 11, and a vibration element 9. The element mounting member 11 has an upper surface recess 31 of rectangular bottom face, and a pair of element pads 29 located at two corners of the bottom face of the upper surface recess 31. The vibration element 9 has a crystal piece 15, and a pair of excitation electrodes 17 provided on the opposite principal surfaces of the crystal piece 15. The vibration element is placed oppositely to the bottom face of the upper surface recess 31, and supported by the pair of element pads 29 while being connected electrically therewith. Furthermore, the element mounting member 11 has a pair of pedestal pads 30 located at other two corners of the bottom face of the upper surface recess 31, and rising from the bottom face.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a piezoelectric device such as a crystal resonator or a crystal oscillator.

  As a piezoelectric device, a crystal resonator or a crystal oscillator for generating an oscillation signal that vibrates at a predetermined frequency is known (for example, Patent Documents 1 and 2). Patent Document 1 discloses an oven controlled crystal oscillator (OCXO) in which a crystal resonator is housed in a thermostatic chamber.

  A crystal device such as a crystal resonator or a crystal oscillator has a crystal resonator element (piezoelectric resonator element) configured by providing a pair of excitation electrodes on both main surfaces of a plate-shaped crystal piece. The crystal resonator element is mounted on a mounting surface of an element mounting member that constitutes a part of the package of the crystal device (for example, the bottom surface of the recess of the element mounting member). Patent Document 2 proposes to provide an inclined surface on the mounting surface of the element mounting member in order to improve the positioning accuracy of the crystal vibration element with respect to the element mounting member.

JP 2006-311496 A Japanese Patent Laying-Open No. 2015-89037

  Unintentional stress may be applied to the piezoelectric vibration element. For example, when an element mounting member is mounted on a circuit board, deformation (stress) occurs in the element mounting member due to a difference in thermal expansion between the element mounting member and the circuit board. This stress is transmitted to the piezoelectric vibration element via a joint portion between the element mounting member and the piezoelectric vibration element. This unintended stress causes a change in the characteristics of the piezoelectric vibration element.

  Therefore, it is preferable to provide a piezoelectric device that can reduce the possibility of unintended stress occurring in the piezoelectric vibration element.

  A piezoelectric device according to one aspect of the present invention includes an element mounting member including a concave portion having a rectangular bottom surface and a pair of element pads positioned at two corners of the bottom surface, a piezoelectric element plate, and the piezoelectric element. It has a pair of excitation electrodes provided on both main surfaces of the base plate, is disposed opposite to the bottom surface of the recess in the recess, is supported by and electrically connected to the pair of element pads. The element mounting member has a pair of pedestal portions that are located at the other two corners of the bottom surface of the recess and rise from the bottom surface.

  Preferably, the piezoelectric device further includes a pair of conductive pieces bonded to the upper surfaces of the pair of element pads and extending from the bonding position along the bottom surface of the concave portion, and the piezoelectric vibration element includes: The pair of conductive pieces are supported on and electrically connected to the pair of element pads by bonding to the upper surface on the tip side of the bonding position with the pair of element pads. The pair of pedestals are opposed to the lower surface of the pair of conductive pieces on the tip side.

  Preferably, the piezoelectric element plate includes a pair of plate-like main body portions where the pair of excitation electrodes are located on both main surfaces and a pair extending from an outer edge of the main body portion in a plan view of the main surface of the main body portion. And the vibration element has a pair of wirings extending from the pair of excitation electrodes and extending on the surface of the pair of frame portions along the pair of frame portions. The pair of wirings are joined to the upper surface of the pair of element pads, thereby being supported by and electrically connected to the pair of element pads. Is opposed to the lower surface of the portion of the pair of frame portions between the connection position with the main body portion and the position where the pair of frame portions are joined to the pair of element pads.

  Preferably, the vibration element has the pair of excitation electrodes on the center side of both main surfaces of the piezoelectric element plate, and extends from the pair of excitation electrodes, so that the concave portion of the piezoelectric element plate is formed. A pair of extraction electrodes positioned at the edge of the main surface opposite to the bottom surface of the substrate, and the pair of extraction electrodes are joined to the pair of element pads, thereby the pair of element pads. The pair of pedestals are opposed to the piezoelectric element.

  Preferably, the pair of pedestal portions are made of a conductive layer having the same height and the same material as the pair of element pads.

  Preferably, the pair of pedestal portions are positioned at two adjacent corners of the bottom surface of the recess, and the top surfaces of the pair of pedestal portions are inclined so that the sides adjacent to each other are lower. .

  According to said structure, the possibility that unintended stress may arise in a piezoelectric vibration element can be reduced.

1A is a perspective view of the crystal resonator according to the first embodiment of the present invention as viewed from the upper surface side, and FIG. 1B is a perspective view of the crystal resonator of FIG. 1A as viewed from the lower surface side. . The exploded perspective view which looked at the crystal oscillator of Drawing 1 from the upper surface side. The exploded perspective view which looked at the crystal oscillator of Drawing 1 from the undersurface side. 4A is a plan view showing the inside of the crystal resonator of FIG. 1, and FIG. 4B is a sectional view taken along line IVb-IVb of FIG. The exploded perspective view which looked at the crystal oscillator concerning a 2nd embodiment of the present invention from the upper surface side. The disassembled perspective view which looked at the crystal oscillator of FIG. 5 from the lower surface side. 7A is a plan view showing the inside of the crystal resonator of FIG. 5, and FIG. 7B is a cross-sectional view taken along the line VIIb-VIIb of FIG. 7A. 8A is a plan view showing the inside of the crystal resonator according to the third embodiment of the present invention, FIG. 8B is a cross-sectional view taken along the line VIIIb-VIIIb in FIG. 8A, and FIG. These are sectional drawings in the VIIIc-VIIIc line of Drawing 8 (a). The figure which shows the application example of a crystal oscillator.

  Hereinafter, a piezoelectric device according to an embodiment of the present invention will be described with reference to the drawings. Note that the drawings used in the following description are schematic, and the dimensional ratios and the like on the drawings do not necessarily match the actual ones. Further, for convenience of explanation, the drawings are provided with an orthogonal coordinate system including a D1 axis, a D2 axis, and a D3 axis that are orthogonal to each other.

  The piezoelectric device may be either upward or downward, but hereinafter, for convenience, terms such as an upper surface and a lower surface will be used with the positive side in the D3 axis direction as the upper side.

  Similar parts or members may be given different numbers and uppercase alphabet letters, such as “first excitation electrode 17A” and “second excitation electrode 17B”. In this case, simply “excitation electrode” 17 ”or the like.

  In the description of the second and subsequent embodiments, configurations that are the same as or similar to the configurations of the embodiments that have already been described are denoted by the same reference numerals as those that have been applied to the configurations of the embodiments that have already been described, and description thereof will be omitted. is there. In addition, even if a configuration corresponding to (similar to) the configuration of the embodiment already described is denoted by a reference numeral different from the configuration of the embodiment already described, matters that are not particularly described are described in detail. The configuration is the same as that of the embodiment.

<First Embodiment>
FIG. 1A is a perspective view of a crystal resonator 1 according to the first embodiment of the present invention (hereinafter, “crystal” may be abbreviated as “vibrator 1”) as viewed from above. is there. FIG. 1B is a perspective view of the vibrator 1 viewed from the lower surface side.

  The vibrator 1 is a piezoelectric device used to generate an oscillation signal that vibrates at a predetermined frequency. The size of the vibrator 1 may be appropriate. For example, in a comparatively small thing, the length (D1-axis direction or D2-axis direction) in planar view is 1-2 mm, and thickness (D3-axis direction) is 0.2-0.4 mm.

  The external shape of the vibrator 1 (its package 3) is, for example, approximately a thin rectangular parallelepiped shape. A plurality of external terminals 5 are provided on the lower surface. The vibrator 1 is disposed with its lower surface facing a mounting surface such as a circuit board (not shown), and a plurality of pads provided on the mounting surface and a plurality of external terminals 5 are a plurality of bumps (not shown). It is mounted by being joined by (for example, solder). In the vibrator 1, an AC voltage is applied to any two of the plurality of external terminals 5.

  More specifically, for example, the outer shape of the vibrator 1 is a rectangular parallelepiped shape having a lower surface recess 7 formed on the lower surface. The shape and size of the lower surface recess 7 may be set as appropriate. For example, the planar shape of the lower surface recess 7 is a generally rectangular shape having four sides parallel to the four sides of the generally rectangular bottom surface of the vibrator 1. Of the lower surface of the vibrator 1, the rectangular frame-shaped portion surrounding the lower surface recess 7 is formed such that one of the four sides (side extending in the D2 axis direction) is wider than the other pair of sides. .

  The plurality of external terminals 5 are provided, for example, at least at the four corners of the lower surface of the crystal unit 1. In the example of FIG. 1, in each of the two sides formed in a wide manner, three are arranged along each side, and a total of six are provided. The external terminal 5 is made of, for example, a conductive material (for example, metal) formed in a layer shape. The planar shape may be set as appropriate, for example, a rectangle.

  Two of the plurality of external terminals 5 are applied with an AC voltage for generating an oscillation signal. The other external terminal 5 is, for example, for mounting the vibrator 1 on a circuit board (not shown) by a bump, and is electrically floated or given a reference potential. Further, for example, the other external terminal 5 may be for applying a reference potential to the lid member 13 described later.

  In the description of the present embodiment, when it is called a rectangular parallelepiped or a rectangle, the shape includes those whose corners are chamfered so as not to impair the overall shape. For example, the rectangle includes one that is 1/10 or less the length of one side and chamfered so that one end of the one side is cut. The chamfering may occur unintentionally depending on the accuracy of etching or the like, or may be intentionally made. In addition, the rectangle includes those whose sides are slightly curved due to the accuracy of etching or the like.

  FIG. 2 is an exploded perspective view of the vibrator 1 as viewed from the upper surface side. FIG. 3 is an exploded perspective view of the vibrator 1 as viewed from the lower surface side.

  The vibrator 1 includes, for example, a crystal vibration element 9 (hereinafter, sometimes referred to as “vibration element 9”), which generates mechanical vibration when an alternating voltage is applied, and a vibration element. A box-shaped element mounting member 11 that accommodates 9, a lid member 13 that seals the opening of the element mounting member 11, and an interposition part 10 that is interposed between the crystal resonator element 9 and the element mounting member 11. ing. The package 3 includes an element mounting member 11 and a lid member 13. For example, the inside of the package 3 is evacuated or sealed with nitrogen. These specific configurations are, for example, as follows.

  The vibration element 9 includes, for example, a crystal piece 15, a first excitation electrode 17A (FIG. 2) and a second excitation electrode 17B (FIG. 3) for applying a voltage to the crystal piece 15, and the vibration element 9 as an element mounting member. 11 has a first extraction electrode 19A and a second extraction electrode 19B (FIG. 3). The first extraction electrode 19A is connected to the first excitation electrode 17A, and the second extraction electrode 19B is connected to the second excitation electrode 17B.

  The crystal piece 15 is a member that generates mechanical vibration when an alternating voltage is applied by a pair of excitation electrodes 17. The crystal piece 15 is formed, for example, in a plate shape having a constant thickness as a whole. The planar shape may be an appropriate shape, and in the present embodiment, a circular shape with a part cut. From another viewpoint, the crystal piece 15 has a curved outer peripheral surface that swells outward in a plan view.

  The excitation electrode 17 and the extraction electrode 19 are made of a conductive layer formed on the surface of the crystal piece 15. The conductive layer (the same applies to other conductive layers described later) is made of, for example, metal, and may be configured by laminating two or more types of conductive layers.

  The pair of excitation electrodes 17 are located, for example, on the center side of both main surfaces of the crystal piece 15 and face each other across the crystal piece 15. The pair of excitation electrodes 17 have, for example, the same shape and size as each other, and are completely overlapped in plan view. The shape of the excitation electrode 17 may be an appropriate shape. In the present embodiment, the circular shape is concentric with the outer edge of the crystal piece 15.

  For example, the first extraction electrode 19 </ b> A extends from the first excitation electrode 17 </ b> A to the radially outer side of the main surface of the crystal piece 15 on the first excitation electrode 17 </ b> A side, and passes through the outer peripheral surface of the crystal piece 15. 15 to the main surface of the second excitation electrode 17B side (element mounting member 11 side). Further, the second extraction electrode 19B extends, for example, the main surface of the crystal piece 15 on the second excitation electrode 17B side outward from the second excitation electrode 17B in the radial direction to the outer edge of the main surface. The ends of the pair of extraction electrodes 19 serve as element terminals 25 for mounting the vibration element 9 on the element mounting member 11 via the interposition part 10 as will be described later.

  The position of the pair of element terminals 25 may be an appropriate position as long as it is a position on the outer peripheral side of the crystal piece 15. In the present embodiment, the position of the pair of element terminals 25 is opposite to the center of the circle of the crystal piece 15. From another viewpoint, the pair of element terminals 25 are positioned on both sides in the D2 axis direction with respect to the pair of excitation electrodes 17 (the center in the present embodiment). Further, the shape and size of the pair of element terminals 25 may be set as appropriate. In the example of FIG. 3, the extraction electrode 19 is formed with a constant width over the whole, and as a result, the pair of element terminals 25 have the same width as the other part (wiring part) of the extraction electrode 19. It is a rectangle.

  Unlike the illustrated example, the second extraction electrode 19B extends through the outer peripheral surface of the crystal piece 15 to the main surface of the crystal piece 15 on the first excitation electrode 17A side, and the tip is the main surface. It may be located on the outer peripheral side. That is, the vibration element 9 may be reversible up and down.

  The element mounting member 11 is similar to, for example, a base body 27 that is the main body of the element mounting member 11, a pair of element pads 29 (FIG. 2) for mounting the vibration element 9, and a pair of element pads 29. The pair of pedestal pads 30 (FIG. 2) configured as described above and the plurality of external terminals 5 described above are provided.

  The base body 27 is made of an insulating material. The insulating material is, for example, ceramic or resin. The base body 27 may be composed of a plurality of members, or may be integrally formed as a whole. The base body 27 may have an appropriate shape as long as the vibration element 9 can be mounted and sealed. For example, the base body 27 has a shape in which an upper surface recess 31 (FIG. 2) is formed on the upper surface of a substantially rectangular parallelepiped and the above-described lower surface recess 7 is formed on the lower surface.

  The upper surface recess 31 is for accommodating the vibration element 9 and the interposition part 10. Its shape and size may be set appropriately. In the present embodiment, the upper surface recess 31 is a rectangle having a planar shape having four sides parallel to the four sides of the upper surface of the base body 27, and the width thereof is wider than the width of the lower surface recess 7.

  The pair of element pads 29 are provided, for example, on the bottom surface of the upper surface recess 31. More specifically, for example, the pair of element pads 29 are located at two adjacent corners among the four corners of the bottom surface of the upper surface recess 31. From another point of view, the pair of element pads 29 are provided side by side along one side of the bottom surface of the upper surface recess 31. The element pad 29 is made of, for example, a conductive layer. The planar shape may be set as appropriate, and is rectangular in the example of FIG.

  One external terminal 5 and one element pad 29 are connected by a connection conductor (not shown), and the other one external terminal 5 and another one element pad 29 are connected by a connection conductor (not shown). Yes. The connection conductor is constituted by, for example, a via conductor or an inner layer conductor provided inside the base body 27. Therefore, as will be described later, when the pair of extraction electrodes 19 and the pair of element pads 29 are connected via the interposition part 10, the pair of excitation electrodes 17 and the two external terminals 5 are electrically connected. Connected to.

  The pair of pedestal pads 30 are used for reinforcing the strength of the element mounting member 11 and / or assisting in mounting the vibration element 9 on the element mounting member 11. The pair of pedestal pads 30 are provided, for example, on the bottom surface of the upper surface recess 31. Therefore, the element mounting member 11 has a pedestal that rises from the mounting surface on which the pair of element pads 29 are provided. The pair of pedestal pads 30 are located at, for example, two corners of the bottom surface of the upper surface recess 31 where the pair of element pads 29 are not provided. In another aspect, the pair of pedestal pads 30 are formed on the pair of element pads 29 at positions away from the pair of element pads 29 in a direction orthogonal to the arrangement direction of the pair of element pads 29. They are arranged in parallel.

  The pedestal pad 30 has, for example, the same configuration as the element pad 29. That is, the pedestal pad 30 is constituted by a metal layer (preferably the same material as the element pad 29) provided on the bottom surface of the upper surface recess 31, and the height thereof is the same as the element pad 29. However, it may be made higher or lower than the element pad 29. The planar shape and the width of the pedestal pad 30 may be appropriately set. In the present embodiment, the shape and the width are substantially the same as those of the element pad 29.

  The pedestal pad 30 is in an electrically floating state, for example. However, the pedestal pad 30 may be applied with the same potential as that of the corresponding element pad 29 in the opposing direction (D1 axis direction) between the pair of element pads 29 and the pair of pedestal pads 30. More specifically, for example, the pedestal pad 30 may be electrically connected to the element pad 29 facing in the D1 axis direction by a wiring (not shown) on the surface of the element mounting member 11 or inside.

  The lid member 13 is constituted by a substantially rectangular metal plate, for example. The lid member 13 is overlapped and joined to the upper surface of the frame portion surrounding the upper surface recess 31 of the element mounting member 11. The joining is performed, for example, by welding metal layers provided on both. The lid member 13 may be made of an insulating material.

  The interposition part 10 has a pair of conductive pieces 21, for example. Each conductive piece 21 is formed in, for example, a substantially long shape, and is disposed between the element mounting member 11 and the vibration element 9, and one end side portion is bonded to the element pad 29 of the element mounting member 11, A portion away from the joining position to the other end side is joined to the element terminal 25 of the vibration element 9. Therefore, the vibration element 9 is elastically supported by the element mounting member 11 as compared with the case where the element terminal 25 is directly bonded to the element pad 29. The arrangement, material, shape, and the like of the pair of conductive pieces 21 may be appropriately set. For example, they are as follows.

  For example, the pair of conductive pieces 21 are aligned in the direction (D2 axis direction) of the pair of element pads 29 while the longitudinal direction thereof coincides with the direction (D1-axis direction) orthogonal to the direction in which the pair of element pads 29 are aligned. In the axial direction). In the following, regarding the description of the pair of conductive pieces 21, the side between the pair of conductive pieces 21 in the D2 axis direction may be referred to as the inside, and the opposite side may be referred to as the outside.

  Each conductive piece 21 is made of, for example, a single metal plate and has an appropriate shape by pressing and / or etching. For example, the conductive piece 21 includes a plate-like base portion 21 a disposed so as to face the bottom surface of the upper surface recess portion 31, and two protruding from the base portion 21 a to the side opposite to the bottom surface of the upper surface recess portion 31 (vibration element 9 side). And a protruding portion 21b.

  The base portion 21a includes, for example, a support portion 21aa that is bonded to the element pad 29, and an extending portion 21ab that extends from the support portion 21aa and to which the element terminal 25 is bonded. The planar shape of the support portion 21aa is, for example, a rectangle. The extending portion 21ab extends linearly from one side of the support portion 21aa with a width shorter than the length of the one side. That is, the base portion 21a is formed wider on the element pad 29 side than on the element terminal 25 side. The protruding portion 21b rises from an outer edge portion of the base portion 21a, for example, and is formed in a wall shape extending at a certain height along the edge portion.

  FIG. 4A is a plan view showing the inside of the vibrator 1 (a plan view with the lid member 13 removed). FIG. 4B is a cross-sectional view taken along line IVb-IVb in FIG. In FIG. 4A, for the sake of convenience, the surfaces of some members (29, 30) (that is, non-cross-sectional surfaces) are hatched.

  As shown in FIG. 4B, the element mounting member 11 is configured by stacking, for example, three layers of members. Specifically, the element mounting member 11 includes the flat substrate portion 27a, the upper surface frame portion 27b that forms the upper surface recess portion 31 on the upper surface side of the substrate portion 27a, and the lower surface recess portion 7 on the lower surface side of the substrate portion 27a. And a lower surface frame portion 27c. The upper surface of the substrate portion 27a constitutes the bottom surface of the upper surface recess 31.

  As shown in FIGS. 4A and 4B, the conductive piece 21 has the support portion 21aa located on the element pad 29 and the tip of the extension portion 21ab located on the pedestal pad 30. Be placed. The element pad 29 and the support portion 21aa are joined by the conductive bump 33 (FIG. 4B). Thereby, the conductive piece 21 is fixed to the element mounting member 11 and electrically connected thereto. The bump 33 is made of, for example, a conductive adhesive. The conductive adhesive is configured, for example, by mixing a conductive filler in a thermosetting resin. The tip of the extending portion 21ab floats from the pedestal pad 30 at a height substantially corresponding to the thickness of the bump 33.

  The vibration element 9 is disposed to face the bottom surface of the upper surface recess 31. At this time, the vibration element 9 is arranged so that the arrangement direction of the pair of element terminals 25 matches the arrangement direction of the element pads 29. The pair of element pads 29 are positioned on one side of the bottom surface of the upper surface recess 31, and the pair of element terminals 25 are positioned on the same straight line passing through the center of the vibration element 9. The position of the element pad 29 and the position of the pair of element terminals 25 are separated from each other in the direction (D1 axis direction) orthogonal to the arrangement direction of the pair of element pads 29.

  When the vibration element 9 is disposed on the conductive piece 21 so as to face the bottom surface of the upper surface recess 31, the vibration element 9 includes the pair of excitation electrodes 17 that are accommodated between the pair of conductive pieces 21 in a plan view. In addition, a pair of element terminals 25 on both sides thereof overlaps with the extending portion 21ab of the pair of conductive pieces 21. The pair of element terminals 25 and the pair of extending portions 21ab are joined by a pair of conductive bumps 35 (FIG. 4B). Accordingly, the vibration element 9 is fixed to the pair of conductive pieces 21 and is electrically connected to the pair of conductive pieces 21. As a result, the vibration element 9 is supported (fixed) and electrically connected to the element mounting member 11 via the pair of conductive pieces 21. The configuration of the bump 35 is the same as that of the bump 33, for example.

  A part of the vibration element 9 on the side where the pair of element terminals 25 is provided fits between the two protruding portions 21 b of each conductive piece 21. Thereby, the vibration element 9 is positioned in the plane direction (D1-axis direction and D2-axis direction). In addition, it is preferable that the vibration element 9 abuts on the four protrusions 21b in total (fits in the gaps between the four protrusions 21b), but may actually be separated by a minute gap.

  The method for manufacturing the vibrator 1 described above may be substantially the same as the conventional method for manufacturing the vibrator except that the vibration element 9 is mounted via the conductive piece 21. At the time of mounting, for example, bumps 33 (conductive adhesive) are first applied on the element pads 29 using a dispenser or the like. Next, the conductive piece 21 is placed on the bump 33, the bump 33 is cured, and the conductive piece 21 is bonded to the element pad 29. Next, a bump 35 (conductive adhesive) is applied on the conductive piece 21 using a dispenser or the like. Next, the vibration element 9 is placed on the bump 35, the bump 35 is cured, and the vibration element 9 is bonded to the conductive piece 21.

  As described above, the vibrator 1 according to this embodiment includes the element mounting member 11 and the vibration element 9. The element mounting member 11 includes an upper surface recess 31 having a rectangular bottom surface and a pair of element pads 29 located at two corners of the bottom surface of the upper surface recess 31. The vibration element 9 has a crystal piece 15 and a pair of excitation electrodes 17 provided on both main surfaces of the crystal piece 15, and is disposed opposite to the bottom surface of the upper surface recess 31 in the upper surface recess 31. The element pad 29 is supported and electrically connected. Further, the element mounting member 11 has a pair of pedestal pads 30 that are located at the other two corners of the bottom surface of the upper surface recess 31 and rise from the bottom surface.

  Therefore, for example, the board portion 27a of the element mounting member 11 becomes thicker as much as the base pad 30 is provided. Thereby, the strength of the substrate part 27a is reinforced, and the risk of deformation of the substrate part 27a at the corner of the bottom surface of the upper recess 31 is reduced. As a result, the possibility that unintended stress is generated in the vibration element 9 is reduced, and consequently, the possibility of the characteristic change of the vibration element 9 is reduced. Further, for example, since the base pad 30 reinforces the substrate portion 27a at the two corners of the bottom surface of the upper surface recess 31 where the element pads 29 are not located, the substrate portion 27a is generally thickened. Compared to the above, an increase in the size of the element mounting member 11 is suppressed. From another viewpoint, the dead space below the vibration element 9 is effectively used. Further, by stacking the metal pedestal pad 30 on the corners of the ceramic element mounting member 110, as a result, the four corners become a composite material, compared with the case where the metal pedestal pad 30 is not provided. It becomes possible to increase the toughness of the four corners.

  In the present embodiment, the vibrator 1 is further bonded to the upper surface of the pair of element pads 29 and further has a pair of conductive pieces 21 extending from the bonding position along the bottom surface of the upper surface recess 31. . The vibration element 9 is supported on the pair of element pads 29 and is electrically connected to the upper surface on the tip side of the pair of conductive pieces 21 with respect to the bonding position with the pair of element pads 29. Connected. The pair of pedestal pads 30 are opposed to the lower surfaces on the tip side of the pair of conductive pieces 21.

  Therefore, for example, when the element mounting member 11 is deformed and a relative displacement occurs between the pair of element pads 29 and this relative displacement may cause stress in the vibration element 9, at least the relative displacement is generated. A part is absorbed by the deformation of the pair of conductive pieces 21. As a result, the stress transmitted to the vibration element 9 is relaxed. Further, for example, when the pair of conductive pieces 21 are mounted on the element mounting member 11, even if the tip of the extension portion 21 ab (an opposite side to the support portion 21 aa) is inclined, the extension portion 21 ab The tip is supported by the pedestal pad 30 so that the inclination is suppressed. As a result, variation in mounting of the conductive piece 21 is suppressed. When the bumps 33 are cured and contracted, the conductive pieces 21 are separated from the pedestal pads 30 by lifting the tips of the extending portions 21ab. Therefore, the base pad 30 does not adversely affect the vibration of the vibration element 9. Even if the conductive piece 21 does not float from the pedestal pad 30, the vibration element 9 itself is not supported by the pedestal pad 30, but the conductive piece 21 is supported by the pedestal pad 30. The influence on the vibration of 9 is reduced.

  In the present embodiment, the pair of base pads 30 are made of a conductive layer having the same height and the same material as the pair of element pads 29.

  Therefore, for example, the pedestal portion (pedestal pad 30) can be formed simply by changing the shape of the mask when forming the element pad 29, and the manufacturing method is simple. Further, for example, it becomes easy to balance the influence of the element pad 29 on the deformation of the element mounting member 11 and the influence of the base pad 30 on the deformation of the element mounting member 11. As a result, for example, the possibility that a biased deformation occurs in the element mounting member 11 is reduced, and consequently, the possibility of the characteristic change of the vibration element 9 is reduced.

Second Embodiment
FIG. 5 is an exploded perspective view of the crystal resonator 201 according to the second embodiment of the present invention as viewed from the upper surface side. FIG. 6 is an exploded perspective view of the vibrator 201 as viewed from the lower surface side. As can be understood from FIGS. 5 and 6, the appearance of the vibrator 201 is the same as the appearance of the vibrator 1 of the first embodiment (FIGS. 1A and 1B).

  The vibrator 201 includes an element mounting member 11 and a lid member 13 and a crystal resonator element 209 accommodated therein. The configurations of the element mounting member 11 and the lid member 13 are substantially the same as those of the first embodiment. In the first embodiment, a pair of conductive pieces 21 are interposed between the vibration element 9 and the element mounting member 11, whereby the vibration element 9 is elastically supported. On the other hand, in this embodiment, the vibration element 9 itself is provided with a structure for elastic support. Specifically, it is as follows.

  The vibration element 209 includes, for example, a crystal piece 215, a first excitation electrode 217A (FIG. 5) and a second excitation electrode 217B (FIG. 6) for applying a voltage to the crystal piece 215, and the vibration element 209 as an element mounting member. 11 has a first wiring 219A (FIG. 5) and a second wiring 219B (FIG. 6) to be mounted on it. The first wiring 219A is connected to the first excitation electrode 217A, and the second wiring 219B is connected to the second excitation electrode 217B.

  For example, the crystal piece 215 is the same as the crystal piece 15 of the first embodiment except for its planar shape. The crystal piece 215 includes, for example, a plate-like main body 221 and a first frame part 223A and a second frame part 223B extending from the main body part 221.

  The main body portion 221 is a portion that generates mechanical vibration when an AC voltage is applied by a pair of excitation electrodes 217. The planar shape of the main body 221 may be an appropriate shape, and is a rectangle in this embodiment. That is, the outer edge of the main body 221 has a first side 221a, a second side 221b and a third side 221c orthogonal to the first side 221a, and a fourth side 221d parallel to the first side 221a. Yes.

  The pair of frame parts 223 are fixed to the element mounting member 11 and support the main body part 221. Therefore, the main body 221 is elastically supported as compared with the case where the main body 221 is directly fixed to the element mounting member 11.

  The pair of frame parts 223, for example, extend from the outer edge of the main body part 221, bend, and extend along the outer edge of the main body part 221 (in another viewpoint, around the main body part 221). Accordingly, the frame portion 223 can be lengthened while suppressing the increase in size of the vibration element 209, and the elastic support effect can be enhanced.

  More specifically, for example, the pair of frame parts 223 first extends from the first side 221a of the main body part 221 in a direction orthogonal to the first side 221a. In another aspect, the pair of frame portions 223 extend in the same direction from the outer edge of the main body portion 221. Next, the pair of frame parts 223 bend in opposite directions and extend along the first side 221a and the second side 221b or the third side 221c of the main body part 221. At this time, for example, the pair of frame portions 223 extend in parallel to each side. For example, the ends of the pair of frame portions 223 are bent so as to be parallel to the fourth side 221d.

  As described above, in the present embodiment, each frame portion 223 extends over a quarter or more and less than a half turn around the main body portion 221 so as to surround the main body portion 221 as a pair of frame portions 223 as a whole. It extends to. In another aspect, the frame portion 223 extends to the opposite side of the main body portion 221 from the side extending from the main body portion 221.

  Note that how many rounds the frame part 223 extends around the main body part 221 is, for example, a straight line drawn from the center of the main body part 221 (for example, the center of gravity of the figure) to the root of the frame part 223 in plan view, and the center The angle may be determined by the angle with the straight line drawn from the frame to the tip of the frame part 223. That is, the determination may be made based on the central angle from the base of the frame portion 223 to the tip around the center of the main body portion 221. In this determination, the position of the frame portion 223 may be determined based on, for example, a center line (a line connecting graphic centroids of cross sections orthogonal to the extending direction). For example, it can be said that one frame portion 223 extends over a quarter of a circle or more when the central angle is 90 ° or more.

  The width of the frame part 223 may be set as appropriate. The width of the frame portion 223 is, for example, substantially constant over the entire length. The width of the frame part 223 is, for example, equal to or greater than a width that allows the frame part 223 to support the main body part 221. At this time, of course, not only the simple weight of the main body 221 but also the vibration of the main body 221 and the acceleration (allowable range) applied to the vibrator 201 are taken into account. In addition, the width of the frame portion 223 is, for example, less than ½ of the short side (minimum diameter in another viewpoint) of the main body portion 221. If the width is larger than this, although depending on the length of the frame portion 223, the effect of elastic support compared to the case where the main body portion 221 is directly fixed to the element mounting member 11 cannot be expected. .

  The distance between the inner edge of the frame portion 223 and the outer edge of the main body portion 221 may also be set as appropriate. In the present embodiment, the inner edge of the frame part 223 and the outer edge of the main body part 221 are parallel, and the distance between them is constant on each side. This distance is, for example, equal to or greater than the distance at which the main body 221 does not contact the frame 223 when the main body 221 is excited. Further, this distance may be equal to or longer than the distance at which the main body portion 221 does not contact the frame portion 223 when acceleration (within an allowable range) is applied to the vibrator 1. It may be said. In the former case, damage to the main body portion 221 due to contact is suppressed, and in the latter case, the frame portion 223 functions as a stopper of the main body portion 221, thereby overloading the connecting portion between the main body portion 221 and the frame portion 223. Application of various stresses can be suppressed.

  The base portions of the pair of frame portions 223 (portions extending from the first side 221a) are coupled to each other. Thereby, for example, stress concentration in the root portion is suppressed. However, such a coupling portion may not be formed. For example, the width of the coupling portion is equal to the width of the two frame portions 223. However, the width of the coupling portion may be, for example, greater than or equal to the width of one frame portion 223 and less than the width of two frame portions 223.

  Excitation electrode 217 is the same as excitation electrode 17 of the first embodiment except for its planar shape. The pair of excitation electrodes 217 is located, for example, on the center side of both main surfaces of the main body portion 221 and faces each other with the main body portion 221 interposed therebetween. For example, the pair of excitation electrodes 217 have the same shape and size as each other, and completely overlap in a plan view. The shape of the excitation electrode 217 may be an appropriate shape, and in this embodiment, the shape is a rectangle having four sides parallel to the four sides of the main body portion 221.

  The wiring 219 is made of, for example, a conductor layer (metal layer), and the material and thickness thereof are the same as those of the excitation electrode 217, for example. For example, the first wiring 219A extends from the first excitation electrode 217A and extends on the surface of the first frame portion 223A along the first frame portion 223A. Similarly, the second wiring 219B extends from, for example, the second excitation electrode 217B and extends on the surface of the second frame portion 223B along the second frame portion 223B. The tips of the pair of wirings 219 are joined to the element pads 29 (FIG. 5) of the element mounting member 11.

  More specifically, for example, the wiring 219 is a part of the outer edge of the excitation electrode 217 on the first side 221a side (side from which the frame part 223 extends) of the outer edge of the excitation electrode 217 on the main surface of the main body part 221. It extends linearly from (side) and reaches the connection part between the main body part 221 and the frame part 223. That is, the wiring 219 reaches the connection portion at the shortest distance from the excitation electrode 217. Next, in the surface of the frame portion 223, the wiring 219 is continuous with the main surface of the main body 221 where the wiring 219 is provided (the first wiring 219A is the upper surface and the second wiring 219B is the lower surface). It extends along the frame part 223. Therefore, the pair of wirings 219 is basically provided on the opposite surfaces of the crystal piece 15. Further, the wiring 219 extends, for example, with a width over the entire width of the surface of the frame portion 223 where the wiring 219 is provided.

  When the first wiring 219A reaches the tip of the first frame portion 223A, it passes through at least one of the outer peripheral surface, the inner peripheral surface, and the front end surface of the first frame portion 223A (the outer peripheral surface in this embodiment), and is on the opposite side. To the surface (the lower surface, the surface on the element mounting member 11 side). And the front-end | tip (FIG. 6) of 1st wiring 219A is located in the lower surface of the front-end | tip of 1st frame part 223A. This tip constitutes a first element terminal 225 </ b> A that is electrically connected to the element mounting member 11. The second wiring 219B has the tip (FIG. 6) positioned at the tip of the second frame portion 223B. This tip constitutes a second element terminal 225 </ b> B that is electrically connected to the element mounting member 11.

  Unlike the illustrated example, the second wiring 219B extends to the opposite surface (upper surface) via at least one of the outer peripheral surface, the inner peripheral surface and the front end surface of the second frame portion 223B, and the front end thereof. May be located on the upper surface of the tip of the second frame portion 223B. That is, the vibration element 209 may be reversible up and down.

  FIG. 7A is a plan view showing the inside of the vibrator 201. FIG.7 (b) is sectional drawing in the VIIb-VIIb line | wire of Fig.7 (a). In FIG. 7A, for the sake of convenience, the surfaces (that is, non-sectional surfaces) of some members (29, 30) are hatched.

  When the vibration element 209 is disposed so as to face the bottom surface of the upper surface recess 31, the pair of element terminals 225 and the pair of element pads 29 face each other. Both are joined by a pair of bumps 33 interposed therebetween. As a result, the frame portion 223 is fixed to the element mounting member 11, and the vibration element 209 is supported by the element mounting member 11. In addition, the element terminal 225 and the element pad 29 are electrically connected. As a result, the two external terminals 5 and the pair of excitation electrodes 217 are electrically connected.

  The pedestal pad 30 of the element mounting member 11 is a portion between the connection position of the pair of frame parts 223 with the main body part 221 and the position (tip) joined to the pair of element pads 29. Opposite the bottom surface. Specifically, for example, the pedestal pad 30 faces the frame part 223 on the first side 221a side (the side where the frame part 223 extends from the main body part 221) from the center of the main body part 221. More specifically, for example, the base pad 30 overlaps a portion of the frame portion 223 that extends from the first side 221a side to the fourth side 221d side on the first side 221a side. In other words, the pedestal pad 30 overlaps the portion of the frame portion 223 that extends to the side opposite to the side where the frame portion 223 extends from the main body portion 221.

  As in the first embodiment, the pedestal pad 30 may be in an electrically floating state or may be provided with a reference potential. Further, the pedestal pad 30 may be applied with the same potential as the wiring 219 overlapping with itself. The pedestal pad 30 facing the wiring 219 (in the example of FIG. 7, the pedestal pad 30 facing the second wiring 219B) is preferably set to the same potential as the facing wiring 219.

  The manufacturing method of the vibration element 209 and the vibrator 201 described above may be the same as the conventional method of manufacturing the vibration element and the vibrator, except for portions corresponding to specific shapes of these members. For example, the vibration element 209 may be formed by etching a wafer made of crystal to form a crystal piece 215 and depositing a metal to be the excitation electrode 217 and the wiring 219 by vapor deposition or sputtering. Then, a mask pattern for etching and metal film formation may be set in accordance with the shape of the vibration element 209 described above.

  As described above, in the present embodiment, as in the first embodiment, the element mounting member 11 has two corners on the bottom surface of the upper surface recess 31 other than the two corners where the pair of element pads 29 are located. And a pair of pedestal pads 30 rising from the bottom surface. Therefore, the same effect as the first embodiment is achieved. For example, the substrate portion 27a of the element mounting member 11 is reinforced, and the risk that unintended stress is applied to the vibration element 209 is reduced.

  Further, in the present embodiment, the crystal piece 215 extends from the outer edge of the main body 221 in a plan view of the plate-like main body 221 where the pair of excitation electrodes 217 are located on both main surfaces and the main surface of the main body 221. And a pair of frame portions 223 that come out. The vibration element 209 includes a pair of wires 219 extending from the pair of excitation electrodes 217 and extending along the pair of frame portions 223 on the surface of the pair of frame portions 223. By being bonded to the upper surface of the pair of element pads 29, it is supported and electrically connected to the pair of element pads 29. The pair of pedestal pads 30 opposes the lower surface of the portion of the pair of frame portions 223 between the connection position with the main body portion 221 and the position where the pair of pedestal pads 29 are joined to the pair of element pads 29. .

  Therefore, for example, when the element mounting member 11 is deformed and a relative displacement occurs between the pair of element pads 29 and this relative displacement may cause a stress in the main body 221, at least the relative displacement may be generated. A part is absorbed by the deformation of the pair of frame portions 223. As a result, the stress transmitted to the main body 221 is relaxed. Further, for example, when the vibration element 209 is mounted on the element mounting member 11, the pair of frame portions 223 are supported by the pedestal pad 30 even if the first side 221 a side is inclined. Is suppressed. As a result, variations in mounting of the vibration element 209 are suppressed. When the bump 33 is cured and contracted, the vibration element 209 is lifted on the first side 221a side, and the pair of frame portions 223 are separated from the base pad 30. Therefore, the pedestal pad 30 does not adversely affect the vibration of the vibration element 209. Even if the pair of frame portions 223 does not float from the pedestal pad 30, the main body portion 221 is not supported by the pedestal pad 30, but the pair of frame portions 223 are supported by the pedestal pad 30. The influence of the pad 30 on the vibration of the main body 221 is reduced.

<Third Embodiment>
FIG. 8A is a plan view showing the inside of the crystal resonator 301 according to the third embodiment of the present invention. FIG.8 (b) is sectional drawing in the VIIIb-VIIIb line | wire of Fig.8 (a). FIG.8 (c) is sectional drawing in the VIIIc-VIIIc line | wire of Fig.8 (a).

  In the first and second embodiments, the vibration element 9 or the body portion 221 of the vibration element 209 is elastically supported by the pair of conductive pieces 21 or the pair of frame portions 223. On the other hand, in the vibrator 301 of this embodiment, the edge of the vibration element 309 is directly bonded to the element pad 29 of the element mounting member 311. That is, the vibration element 309 is mounted on the element pad 29 by a known general method.

  For example, the vibration element 309 includes a crystal piece 315, a first excitation electrode 317A and a second excitation electrode 317B located on the main surface of the crystal piece 315, a first extraction electrode 319A connected to the pair of excitation electrodes 317, and A second extraction electrode 319B.

  The crystal piece 315 is, for example, a circle or a polygon (in this embodiment, a rectangle), and does not have a frame portion. The pair of excitation electrodes 317 are located, for example, on the center side of the main surface of the crystal piece 315. For example, the first extraction electrode 319A extends from the first excitation electrode 317A and extends to the edge of the main surface on the second excitation electrode 317B side through the outer peripheral surface of the crystal piece 315. The second extraction electrode 319B extends from the second excitation electrode 317B and is located at the edge of the main surface on the second excitation electrode 317B side. The second extraction electrode 319B may extend to the edge of the main surface on the first excitation electrode 317A side (the vibration element 309 may be reversible up and down).

  The vibration element 309 is disposed so as to face the bottom surface of the upper surface recess 31, and the pair of extraction electrodes 319 are joined to the pair of element pads 29 by the bumps 33 (FIG. 8B). As a result, the vibration element 309 is electrically connected while being supported by the element pad 29 at one end side. Further, the other end side of the vibration element 309 floats from the bottom surface of the upper surface recess 31.

  Also in the present embodiment, a pedestal pad 330 is provided on the bottom surface of the upper surface recess 31 of the element mounting member 311 as in the first and second embodiments. The pedestal pad 330 overlaps the end (two corners) of the vibration element 309 opposite to the side bonded to the element pad 29 in plan view. However, it is preferable that the pedestal pad 330 does not overlap the excitation electrode 317. The planar shape of the pedestal pad 330 may be an appropriate shape.

  The pair of pedestal pads 330 are located at, for example, two corners adjacent to each other on the bottom surface of the upper surface recess 31. And as shown in FIG.8 (c), the upper surface of a pair of base pad 330 inclines so that the mutually adjacent side may become low. From another viewpoint, the pair of pedestal pads 330 are formed thicker toward the outside. In addition, such a pedestal pad 30 performs, for example, film formation via a mask or etching via a mask a plurality of times while changing the mask (in this case, the inclined surface has a stepped shape accurately) It may be realized by arranging a polished metal plate so that the thickness changes.

  As described above, in the present embodiment, as in the other embodiments, the element mounting member 311 is located at two corners of the bottom surface of the upper surface recess 31 where the pair of element pads 29 are not located. A pair of pedestal pads 330 that rise from the top. Therefore, the same effect as other embodiments is produced. For example, the substrate portion 27a of the element mounting member 311 is reinforced, and the risk that unintended stress is applied to the vibration element 309 is reduced.

  Further, in the present embodiment, the vibration element 309 has a pair of excitation electrodes 317 on the center side of both main surfaces of the crystal piece 315 and extends from the pair of excitation electrodes 317 so that the upper surface of the crystal piece 315 It has a pair of extraction electrodes 319 located at the edge of the main surface facing the bottom surface of the recess 31, and the pair of extraction electrodes 319 are joined to the pair of element pads 29 to form a pair of elements It is supported by the pad 29 and electrically connected. The pair of pedestal pads 330 faces the vibration element 309.

  Therefore, for example, when the vibration element 309 is mounted on the element mounting member 311, the edge of the vibration element 309 is supported by the pedestal pad 330 even if the vibration element 309 is inclined so that the pedestal pad 330 side is lowered. Therefore, the inclination is suppressed. As a result, variation in mounting of the vibration element 309 is suppressed. When the bumps 33 are cured and contracted, the end of the vibration element 309 on the side of the pedestal pad 330 is lifted and separated from the pedestal pad 330. Therefore, the base pad 330 does not adversely affect the vibration of the vibration element 309. Even if the vibration element 309 does not lift from the pedestal pad 330, the vibration element 309 contacts the pedestal pad 330 only on the ridgeline between the lower surface and the end surface (side surface on the pedestal pad 330 side) of the vibration element 309. Therefore, the influence of the base pad 330 on the vibration of the vibration element 309 is relatively small.

  In the present embodiment, the pair of pedestal pads 330 are positioned at two corners adjacent to each other on the bottom surface of the upper surface recess 31, and the upper surfaces of the pair of pedestal pads 330 are lowered on the sides adjacent to each other. It is inclined.

  Therefore, for example, even if the end of the vibration element 309 on the pedestal pad 330 side is not sufficiently lifted, the vibration element 309 is in contact with the pedestal pad 330 only at both ends of the ridgeline between the lower surface and the end surface. Become. As a result, the possibility that the base pad 330 adversely affects the vibration of the vibration element 309 is reduced.

<Usage example of vibrator>
FIG. 9 is a cross-sectional view showing the configuration of the OCXO 101 having the vibrator 1. That is, FIG. 9 shows a usage example of the vibrator 1. In FIG. 9, the vibrator 1 of the first embodiment is taken as an example, but the vibrator of another embodiment may be used.

  The OCXO 101 includes, for example, the vibrator 1 and a mounting substrate 103 on which the vibrator 1 is mounted. The OCXO 101 includes, for example, an IC 105 and a heater 107 as electronic components other than the vibrator 1 mounted on the mounting substrate 103. Further, the OCXO 101 includes a tank 109 that accommodates each of the above components and an external terminal 111 that is exposed from the tank 109.

  The mounting substrate 103 is constituted by, for example, a rigid printed wiring board. The vibrator 1 has a plurality of external terminals 5 and a plurality of vibrator pads 113 provided on the main surface of the mounting substrate 103 joined by bumps 115 made of solder or the like, whereby the mounting substrate 103 is attached. It is fixed and electrically connected.

  The IC 105 is, for example, for generating an oscillation signal by applying a voltage to the vibrator 1 and includes an oscillation circuit. For example, the IC 105 is fixed to the mounting substrate 103 by bonding the plurality of IC terminals 117 and the plurality of IC pads 119 provided on the main surface of the mounting substrate 103 by bumps 121 made of solder or the like. And electrically connected. The mounting position of the IC 105 may be an appropriate position. In the example of FIG. 9, the IC 105 is mounted at a position where a part of the upper surface side is accommodated in the lower surface recess 7 of the vibrator 1.

  The heater 107 and the bath 109 are for maintaining the atmosphere around the vibrator 1 at a constant temperature, and constitute a thermostatic bath 123. For example, the heater 107 is mounted at a position overlapping the vibrator 1 on the main surface of the mounting substrate 103 opposite to the main surface on which the vibrator 1 is mounted. The tank 109 is made of an appropriate material such as metal or ceramic, and houses the mounting substrate 103 on which the vibrator 1 and the like are mounted. The inside of the tank 109 is preferably sealed, and air or other gas (for example, nitrogen) is present.

  Although not particularly illustrated, a temperature sensor (which may be incorporated in the IC) is provided in the tank 109. The heater 107 is feedback-controlled by an IC (not shown) so that the detection value of the temperature sensor becomes a constant value. Thereby, the temperature in the tank 109 is kept constant. Note that the atmosphere around the vibrator 1 is kept constant by the thermostatic bath 123, but the IC 105 may include a temperature compensation circuit.

  The external terminal 111 is a pin made of metal, for example. One end thereof is inserted into and fixed to the mounting substrate 103 and is electrically connected. As a result, the external terminal 111 is electrically connected to the IC 105 or the like via the mounting substrate 103. The other end of the external terminal 111 extends from the tank 109. The OCXO 101 is mounted on the circuit board by inserting the other end of the external terminal 111 into a circuit board (not shown) and soldering.

  Thus, the vibrator 1 or the like of the embodiment may be used for OCXO. The vibrator arranged in the thermostat is used at a higher temperature than a normal vibrator. However, even if the element mounting member 11 is deformed by heat, the vibrator 1 or the like of the embodiment has a smaller influence on the vibration element 9 or the like than the conventional one. Therefore, the intended frequency characteristic can be easily obtained.

  In the above embodiment, each of the crystal resonators 1, 201, and 301 is an example of a piezoelectric device. Each of the crystal vibration elements 9, 209, and 309 is an example of a piezoelectric vibration element. The crystal pieces 15, 215, and 315 are examples of piezoelectric element plates. The pedestal pads 30 and 330 are examples of pedestal portions.

  The present invention is not limited to the above embodiment, and may be implemented in various aspects.

  The piezoelectric device is not limited to a piezoelectric vibrator such as a crystal vibrator, and may be, for example, a piezoelectric oscillator having an oscillation circuit, or may be an oscillator with a thermostatic bath as shown in FIG. The piezoelectric vibrator may have an electronic element other than a vibration element such as a thermistor. The piezoelectric body (piezoelectric element plate) is not limited to quartz but may be ceramic, for example.

  The entire structure including the package (element mounting member or lid) of the piezoelectric device can be changed as appropriate. For example, a thermistor or IC may be mounted on the bottom surface of the lower surface recess of the element mounting member. You may make it not form the lower surface recessed part of an element mounting member. The element mounting member may have a pin-shaped external terminal.

  The shape of the piezoelectric element plate (or its main body) is not limited to that of the embodiment. For example, the planar shape of the piezoelectric element plate supported by the conductive piece as in the first embodiment may be rectangular, or the shape of the main body part of the piezoelectric element plate provided with the frame part as in the second embodiment. May be circular, or the shape of the piezoelectric element plate whose edges are directly supported as in the third embodiment may be circular. Moreover, when the piezoelectric element plate has a curved outer peripheral surface that swells outward as in the first embodiment, the shape is not limited to a circle, and may be, for example, an ellipse. Further, the side surface of the piezoelectric element may have a so-called mesa shape that protrudes by a curved surface or a stepped surface in a side view (sectional view).

  The conductive piece described in the first embodiment is not limited to a piece made of a metal piece, and for example, a surface of an insulating piece made of resin or the like may be plated. Further, the conductive piece is not limited to a long one, and may be, for example, a rectangle close to a square. In addition, the conductive piece may extend in a curved shape or change in width. The joining of the conductive piece and the pad of the element mounting member is not limited to that made by conductive bumps. For example, joining may be performed by welding.

  The frame portion described in the second embodiment is not limited to the one that extends and bends in a straight line (in another aspect, a rectangular frame shape), and may be curved. For example, when the main body portion is circular, the frame portion may have a circular frame shape. The frame portion may have a shape different from the outer edge of the main body portion. In addition, the pair of frame portions may extend independently from each other from the main body portion, or the tips may be connected to each other. The frame portion does not have to have a constant width. For example, the frame portion may gradually become thinner toward the tip side, or conversely, become thicker. In addition, the frame portion may be appropriately provided with a protrusion or a notch. The thickness of the frame portion may not be the same as that of the main body portion. For example, the frame part may be made thinner than the main body part to increase the effect of elastic support. Conversely, the frame part may be made thicker than the main body part to reduce the possibility that the main body part contacts the mounting surface or the like.

  The pair of element pads may be located at two corners located on the diagonal line of the bottom surface of the recess. Similarly, the pair of pedestal portions may be located at two corners located on the diagonal line of the bottom surface of the recess. In addition, according to such an aspect, the mounting aspect of a vibration element may be changed suitably. For example, the pair of conductive pieces of the first embodiment may be arranged to extend in directions opposite to each other. The pair of frame portions of the second embodiment may be formed so as to extend from opposite sides to the main body portion and extend in the same direction around the main body portion. The pair of extraction electrodes of the third embodiment may be disposed on opposite sides of the excitation electrode.

  The element pad and the pedestal portion may be formed with a relatively large area and may have a portion located on the center side of the bottom surface of the recess. In other words, at least a part of the element pad and the pedestal portion may be located at the corner. For example, the element pad and the pedestal portion may be formed relatively wide so as to overlap the excitation electrode in plan view. Even in this case, for example, in the aspect in which the conductive piece is interposed between the vibration element and the bottom surface of the recess as in the first embodiment, the possibility that the element pad and the excitation electrode are in contact with each other is low.

  Note that when the element pad and the pedestal are located at the corners of the bottom surface of the recess, they do not contact the two edges (two intersecting sides) constituting the corner of the bottom surface of the recess. May be. For example, when the bottom surface of the recess is divided into 4 × 4 squares, if the element pad and the pedestal part are located at the corner, the element pad and the pedestal part are located at the corners. It can be said that. More preferably, when the bottom surface of the recess is divided more finely, such as 5 × 5, 6 × 6, etc., it is preferable that the element pad and the pedestal portion are located in the mass located at the corner.

  The pedestal is not limited to the same configuration as the element pad. For example, the pedestal portion may be formed by forming a part of the insulating base so as to rise. In addition, the pedestal portion having a constant thickness (the top surface is parallel to the bottom surface of the recess) shown in the first embodiment and the second embodiment joins the edge portion of the vibration element to the element pad shown in the third embodiment. It may be combined with the configuration and overlap with the vibration element in a plan view. Conversely, the pedestal portion with the thickness shown in the third embodiment changing (the upper surface is inclined to the bottom surface of the recess) is combined with the conductive piece shown in the first embodiment or the frame portion shown in the second embodiment, They may overlap with each other in plan view.

  DESCRIPTION OF SYMBOLS 1 ... Quartz crystal | crystallization vibrator (piezoelectric device), 9 ... Quartz crystal vibration element (piezoelectric vibration element), 11 ... Element mounting member, 15 ... Quartz piece (piezoelectric base plate), 17A ... 1st excitation electrode, 17B ... 2nd excitation electrode , 29... Element pads, 30... Pedestal pads (pedestal parts), 31.

Claims (6)

An element mounting member having a concave portion having a rectangular bottom surface and a pair of element pads located at two corners of the bottom surface;
A piezoelectric element plate, and a pair of excitation electrodes provided on both main surfaces of the piezoelectric element plate, are arranged in the recess so as to face the bottom surface of the recess, and are supported by the pair of element pads And a piezoelectric vibration element electrically connected
Have
The element mounting member has a pair of pedestal portions that are located at the other two corners of the bottom surface of the recess and rise from the bottom surface. Piezoelectric device. A pair of conductive pieces bonded to the top surfaces of the pair of element pads and extending from the bonding position along the bottom surface of the recess;
The piezoelectric vibration element is supported on the pair of element pads by being bonded to the upper surface of the pair of conductive pieces on the tip side of the bonding position with the pair of element pads. Electrically connected,
The piezoelectric device according to claim 1, wherein the pair of pedestal portions are opposed to a lower surface on a distal end side of the pair of conductive pieces. The piezoelectric element plate is
A plate-like main body portion on which the pair of excitation electrodes are located on both main surfaces;
A pair of frame portions extending from the outer edge of the main body portion in plan view of the main surface of the main body portion,
The vibrating element has a pair of wires extending from the pair of excitation electrodes and extending along the pair of frame portions on the surface of the pair of frame portions, and the pair of wires It is supported and electrically connected to the pair of element pads by being bonded to the upper surface of the pair of element pads.
The pair of pedestal portions are opposed to a lower surface of a portion of the pair of frame portions between a connection position with the main body portion and a position joined to the pair of element pads. 1. The piezoelectric device according to 1. The vibration element has the pair of excitation electrodes on the center side of both main surfaces of the piezoelectric element plate, and extends from the pair of excitation electrodes to face the bottom surface of the recess of the piezoelectric element plate. A pair of extraction electrodes positioned at the edge of the main surface, and the pair of extraction electrodes are joined to the pair of element pads to be supported by the pair of element pads. Is electrically connected with
The piezoelectric device according to claim 1, wherein the pair of pedestals are opposed to the piezoelectric element. The piezoelectric device according to claim 1, wherein the pair of pedestal portions are made of a conductive layer having the same height and the same material as the pair of element pads. The pair of pedestals are located at two corners adjacent to each other on the bottom surface of the recess,
The piezoelectric device according to any one of claims 1 to 4, wherein upper surfaces of the pair of pedestal portions are inclined so that sides adjacent to each other are lowered.

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