WO2017213163A1

WO2017213163A1 - Piezoelectric vibration element

Info

Publication number: WO2017213163A1
Application number: PCT/JP2017/021058
Authority: WO
Inventors: 直與田
Original assignee: 株式会社村田製作所
Priority date: 2016-06-10
Filing date: 2017-06-07
Publication date: 2017-12-14

Abstract

Provided is a piezoelectric vibration element capable of suppressing an increase in capacitance between excitation electrodes. This piezoelectric vibration element is a piezoelectric vibration element comprising: a piezoelectric piece that has first and second principal surfaces; first and second excitation electrodes; a first extraction electrode; and a through conductor. The piezoelectric piece includes: a vibrating part; a frame part that surrounds the periphery of the vibrating part and has a thickness which is greater than or equal to the thickness of the vibrating part; and a first connection part that connects the vibrating part and the frame part. The first and second excitation electrodes are respectively provided on first and second principal surfaces of the vibrating part. The first extraction electrode is connected to the first excitation electrode and is provided on a first principal surface of the first connection part. The through conductor is connected to the first extraction electrode and penetrates the piezoelectric piece so as to connect the first principal surface and the second principal surface. At least a portion of the through conductor is located in the first connection part when viewed from the normal direction of the first principal surface.

Description

Piezoelectric vibration element

The present invention relates to a piezoelectric vibration element, and more particularly to a piezoelectric vibration element having a structure in which a piezoelectric piece is sandwiched between two excitation electrodes.

As an invention related to a conventional piezoelectric vibration element, for example, a piezoelectric device described in Patent Document 1 is known. FIG. 10 is an exploded perspective view of the piezoelectric device described in Patent Document 1. FIG. Hereinafter, the vertical direction in FIG. 10 is simply referred to as the vertical direction.

The piezoelectric device includes a lid plate 510, a base plate 520, a terminal electrode 524, a piezoelectric vibration element 530, and

bonding materials

540 and 542. The lid plate 510, the piezoelectric vibration element 530, and the base plate 520 are stacked in this order from the upper side to the lower side. The excitation electrode 536 is a rectangular electrode provided at the center of the upper surface of the piezoelectric vibrating piece. The extraction electrode 537 is connected to the excitation electrode 536 and is extracted to a corner on the upper surface of the piezoelectric vibration element 530. Accordingly, the lead electrode 537 is connected to the terminal electrode 524 provided on the lower surface of the base plate 520 via the conductor provided at the corner of the piezoelectric vibration element 530 and the corner of the base plate 520.

The bonding material 540 bonds the lid plate 510 and the piezoelectric vibration element 530 together. The bonding material 540 is provided on the outer edge of the lower surface of the lid plate 510 and the outer edge of the upper surface of the piezoelectric vibration element 530 and has a rectangular ring shape. The bonding material 542 bonds the piezoelectric vibration element 530 and the base plate 520 to each other. The bonding material 542 is provided on the outer edge of the lower surface of the piezoelectric vibration element 530 and the outer edge of the upper surface of the base plate 520, and has a rectangular ring shape. The material of the

bonding materials

540 and 542 is, for example, a metal. The

bonding materials

540 and 542 realize hermetic sealing of the piezoelectric device.

Japanese Patent Laying-Open No. 2015-173366

By the way, in the piezoelectric device described in Patent Document 1, when viewed from above, the extraction electrode 537 is arranged so as to overlap the metal bonding material 540. For this reason, the electrostatic capacitance due to the

bonding materials

540 and 542 provided on the upper surface and the lower surface of the piezoelectric vibration element 530 includes the excitation electrode 536 provided on the upper surface of the piezoelectric vibration element 530 and the excitation electrode ( (Not shown). For this reason, there exists a problem that the electrostatic capacitance on the equivalent circuit of a piezoelectric device becomes large. Increasing the capacitance when the piezoelectric device is represented by an equivalent circuit causes problems such as an increase in power consumption due to a decrease in the vibration efficiency of the piezoelectric device and an increased sensitivity to external electromagnetic noise. .

Therefore, an object of the present invention is to provide a piezoelectric vibration element that can suppress an increase in capacitance.

A piezoelectric vibration element according to one embodiment of the present invention includes a piezoelectric piece having a first main surface and a second main surface, a first excitation electrode, a second excitation electrode, and a first extraction electrode. A piezoelectric vibration element comprising: a through conductor, wherein the piezoelectric piece is separated from the vibration part when viewed from a normal direction of the vibration part and the first main surface. A frame portion surrounding the portion and having a thickness equal to or greater than a thickness of the vibration portion, and a first portion connecting the vibration portion and the frame portion when viewed from a normal direction of the first main surface. There is no step between the first main surface of the vibrating portion and the first main surface of the first connecting portion, and the first portion of the frame portion. There is no step between the first main surface and the first main surface of the first connecting portion, and the first excitation electrode is provided on the first main surface of the vibrating portion. The second excitation electrode is provided on the second main surface of the vibrating portion; the first extraction electrode is connected to the first excitation electrode; and The first connecting portion is provided on the first main surface, the through conductor is connected to the first lead electrode, and the first main surface and the second main surface Passing through the piezoelectric piece so as to connect, at least a part of the through conductor is located in the first connecting portion when viewed from the normal direction of the first main surface, Features.

According to the present invention, an increase in capacitance can be suppressed in the piezoelectric vibration element.

FIG. 1 is an exploded perspective view of the crystal unit 10. FIG. 2 is an external perspective view of the crystal resonator element 13 as viewed from below. FIG. 3 is an external perspective view of the substrate 16 as viewed from below. FIG. 4 is a cross-sectional structure diagram of the crystal resonator element 13 taken along the line AA of FIG. FIG. 5 is an exploded perspective view of the crystal unit 10a. FIG. 6 is an external perspective view of the crystal resonator element 13a as viewed from below. FIG. 7 is an exploded perspective view of the crystal unit 10b. FIG. 8 is an external perspective view of the crystal resonator element 13b as viewed from below. FIG. 9 is an exploded perspective view of the crystal unit 10c. FIG. 10 is an exploded perspective view of the piezoelectric device described in Patent Document 1. FIG.

(Embodiment)
Hereinafter, a crystal resonator (Quartz Crystal Resonator Unit) 10 including a crystal resonator element (Quartz Crystal Resonator) 13 according to an embodiment will be described with reference to the drawings. FIG. 1 is an exploded perspective view of the crystal unit 10. FIG. 2 is an external perspective view of the crystal resonator element 13 as viewed from below. FIG. 3 is an external perspective view of the substrate 16 as viewed from below. FIG. 4 is a cross-sectional structure diagram of the crystal resonator element 13 taken along the line AA of FIG.

Hereinafter, the normal direction of the upper surface of the crystal piece (Quartz Crystal Blank) 14 of the crystal resonator element 13 is defined as the vertical direction. Further, when the crystal piece 14 is viewed from above, the direction in which the long side extends is defined as the left-right direction, and the direction in which the short side extends is defined as the front-rear direction. However, the up-down direction, the front-rear direction, and the left-right direction are examples, and need not coincide with the up-down direction, the front-rear direction, and the left-right direction when the crystal unit 10 is actually used.

The crystal resonator 10 includes a cap 12, a crystal resonator element 13, and a substrate 16, as shown in FIG. As shown in FIGS. 1 and 2, the crystal resonator element 13 includes a crystal piece 14,

excitation electrodes

20 and 22,

lead electrodes

24 and 26,

bonding materials

36 and 38, a pad electrode 39, and a via-hole conductor v1.

The crystal piece 14 which is an example of a piezoelectric piece is a plate-like crystal piece having an upper surface which is an example of a first main surface and a lower surface which is an example of a second main surface. The top surface of the crystal piece 14 has a rectangular shape with long sides extending in the left-right direction when viewed from above. The crystal piece 14 is, for example, an AT cut type cut out from a rough crystal or the like at a predetermined angle.

The crystal piece 14 includes a vibrating portion 14a, a flange portion 14b, a frame portion 14c, and connecting

portions

14d and 14e. The vibration part 14a vibrates at a predetermined frequency and has a rectangular shape when viewed from above. The frame portion 14c surrounds the periphery of the vibration portion 14a in a state of being separated from the vibration portion 14a when viewed from above. That is, the frame portion 14c, which is an example of the bonding material, has an annular shape whose outer shape is rectangular when viewed from above. However, the frame portion 14c is not directly connected to the vibrating portion 14a. Further, the frame portion 14c has a thickness equal to or greater than the thickness of the vibration portion 14a. In the present embodiment, the thickness of the frame portion 14c and the thickness of the vibrating portion 14a are substantially equal. Below, thickness means the thickness of an up-down direction. Further, the upper surface of the frame portion 14c and the upper surface of the vibrating portion 14a are located at substantially the same height in the vertical direction. The lower surface of the frame part 14c and the lower surface of the vibration part 14a are located at substantially the same height in the vertical direction.

The flange portion 14b is provided between the vibrating portion 14a and the frame portion 14c when viewed from above. When viewed from above, the flange portion 14b is in contact with the vibration portion 14a at the inner peripheral portion thereof and surrounds most of the periphery of the vibration portion 14a in a state of being in contact with the frame portion 14c at the outer peripheral portion thereof. . That is, the flange portion 14b has a rectangular frame shape with a part cut when viewed from above. On the upper surface of the crystal piece 14, there is provided a groove-like recess G1 that draws a rectangular shape with a part cut off. The concave portion G1 is formed by the upper surface of the crystal piece 14 being depressed. Further, on the lower surface of the crystal piece 14, there is provided a groove-shaped recess G2 that draws a rectangular shape with a part cut off. The recess G2 is formed by the depression of the lower surface of the crystal piece 14. And the flange part 14b is an area | region pinched | interposed into the recessed part G1 and the recessed part G2 from the up-down direction. That is, the upper surface and the lower surface of the crystal piece 14 are recessed in the flange portion 14b. Thereby, the flange part 14b has thickness smaller than the thickness of the vibration part 14a and the frame part 14c.

However, the recess G1 is interrupted at the center of the left short side when viewed from above. Similarly, when viewed from above, the recess G2 is interrupted at the center of the right short side. Further, as described above, the flange portion 14b is a region sandwiched from above and below by the concave portion G1 and the concave portion G2 in the crystal piece 14. Therefore, when viewed from above, the flange portion 14b has a shape in which the center of the short side on the right side and the center of the short side on the left side are interrupted.

The connection part 14d which is an example of a 1st connection part has connected the center of the short side of the left side of the vibration part 14a, and the center of the short side of the left side of the frame part 14c, when it sees from upper side, It has a strip shape extending in the direction. Thereby, the recessed part G1 is interrupted in the center of the left short side. There is no step between the upper surface of the vibrating part 14a and the upper surface of the connecting part 14d. Further, there is no step between the upper surface of the frame portion 14c and the upper surface of the connecting portion 14d. In the present embodiment, the upper surface of the vibrating portion 14a, the upper surface of the frame portion 14c, and the upper surface of the connecting portion 14d are positioned at the same height in the vertical direction.

The connection part 14e which is an example of a 2nd connection part has connected the center of the short side of the right side of the vibration part 14a, and the center of the short side of the right side of the frame part 14c, when it sees from the lower side, It has a strip shape extending in the left-right direction. Thereby, the recessed part G2 is interrupted in the center of the short side on the right side. There is no step between the lower surface of the vibrating portion 14a and the lower surface of the connecting portion 14e. Further, there is no step between the lower surface of the frame portion 14c and the lower surface of the connecting portion 14e. In the present embodiment, the lower surface of the vibration portion 14a, the lower surface of the frame portion 14c, and the lower surface of the connecting portion 14e are positioned at the same height in the vertical direction.

Further, when viewed from above, the portion of the lower surface of the crystal piece 14 that overlaps the connecting portion 14d is depressed as shown in FIG. That is, the recess G 2 is provided on the lower surface of the crystal piece 14. Similarly, the part which overlaps with the connection part 14e in the upper surface of the crystal piece 14 is depressed as shown in FIG. That is, the concave portion G 1 is provided on the upper surface of the crystal piece 14.

The excitation electrode 20, which is an example of the first excitation electrode, is a conductor layer provided on the upper surface of the vibration portion 14a, and has a rectangular shape when viewed from above. The excitation electrode 22, which is an example of the second excitation electrode, is a conductor layer provided on the lower surface of the vibrating portion 14a, and has a rectangular shape when viewed from below. As a result, the excitation electrode 20 and the excitation electrode 22 sandwich the vibrating portion 14a from above and below.

The extraction electrode 24, which is an example of a first extraction electrode, is connected to the excitation electrode 20 at the right end thereof and is provided on the upper surface of the coupling portion 14d. The left end of the connecting portion 14d is located near the boundary between the connecting portion 14d and the frame portion 14c.

The extraction electrode 26, which is an example of a second extraction electrode, is connected to the excitation electrode 22 at the left end and is provided on the lower surface of the coupling portion 14e. The right end of the connecting portion 14e is located near the boundary between the connecting portion 14e and the frame portion 14c. The

excitation electrodes

20 and 22 and the

extraction electrodes

24 and 26 have, for example, a configuration in which an Au layer is provided on a Cr underlayer by a plating method.

A via-hole conductor v1, which is an example of a through conductor, is connected to the extraction electrode 24 and penetrates the crystal piece 14 in the vertical direction so as to connect the upper surface and the lower surface. More specifically, the via-hole conductor v1 is located at the boundary between the connecting portion 14d and the frame portion 14c when viewed from above. Thereby, the via-hole conductor v 1 is connected to the left end of the extraction electrode 24. Further, the right half of the via hole conductor v1 (an example of a part of the through conductor) is positioned at the connecting portion 14d when viewed from above, and the left half of the via hole conductor v1 is framed when viewed from above. It is located in the part 14c. In addition, the via-hole conductor v1 has a structure in which a through hole penetrating the crystal piece 14 in the vertical direction is filled with a conductor. However, the via-hole conductor v1 does not need to have a structure in which the through hole is filled with the conductor, and may have a structure in which the inner peripheral surface of the through hole is covered with the conductor. The via-hole conductor v1 has a configuration in which, for example, a conductive paste containing a material of Ag or AgPd is filled in the via hole and then sintered.

The pad electrode 39 is provided on the lower surface of the crystal piece 14 and is a conductor that forms a circle when viewed from below. The pad electrode 39 is connected to the lower end of the via-hole conductor v1. The pad electrode 39 has, for example, a configuration in which an Au layer is provided on a Cr underlayer by a plating method.

The bonding material 36 is provided on the upper surface of the crystal piece 14 and is a rectangular frame-shaped conductor provided along the outer edge of the upper surface of the crystal piece 14. As a result, the lead electrode 24 and the via-hole conductor v1 are located in a region surrounded by the bonding material 36 and are not in contact with the bonding material 36 when viewed from above. The bonding material 36 functions as a sealing member that fills the gap between the cap 12 and the upper surface of the crystal piece 14. The material of the bonding material 36 is, for example, Au. Further, when viewed from the upper side, the extraction electrode 24 is located in a region surrounded by the bonding material 36 and is disposed without overlapping the frame-shaped bonding material 36. Thereby, the distance between the bonding material 38 and the extraction electrode 24 can be made larger than the length of the bonding material 36 in the thickness direction. Therefore, the capacitive coupling between the extraction electrode 24 and the bonding material 36 can be reduced. As a result, the capacitance between the bonding material 36 and the bonding material 38 added via the extraction electrode 24 to the capacitance between the excitation electrode 20 and the excitation electrode 22 can be reduced. Furthermore, since the bonding material 36 and the extraction electrode 24 can be arranged without overlapping in plan view, the length in the thickness direction of the bonding material 36 at the overlapping portion with the extraction electrode 24 does not increase. Therefore, the thickness of the bonding material 36 becomes uniform, and the bonding strength of the bonding material 36 can be increased. As a result, the hermetic sealing of the crystal unit 10 can be reliably performed.

The bonding material 38 is a rectangular frame-shaped conductor provided on the lower surface of the crystal piece 14 and provided along the outer edge of the lower surface of the crystal piece 14. Thereby, when viewed from the lower side, the extraction electrode 26 is located in a region surrounded by the bonding material 38 and is not in contact with the bonding material 38. The bonding material 38 functions as a sealing member that fills a gap between the upper surface of the substrate body 17 and the lower surface of the crystal piece 14. The material of the bonding material 38 is, for example, Au. Furthermore, when viewed from the upper side, the extraction electrode 26 is located in a region surrounded by the bonding material 36 and is disposed without overlapping the frame-shaped bonding material 38. Thereby, the distance between the bonding material 38 and the extraction electrode 26 can be made larger than the length of the bonding material 38 in the thickness direction.

The cap 12 is a box-shaped housing having a rectangular parallelepiped shape with a space inside, and has a shape substantially coincident with the upper surface of the crystal piece 14 when viewed from above. Further, the lower surface of the cap 12 is open. The outer edge of the opening of the cap 12 has a shape that substantially matches the bonding material 36. The cap 12 is fixed on the upper surface of the crystal piece 14 by bonding the outer edge of the opening to the bonding material 36. Thereby, the upper surface of the crystal piece 14 is covered with the cap 12. However, since the cap 12 has a box shape, it is not in contact with the excitation electrode 20. Therefore, the cap 12 does not inhibit the vibration of the crystal piece 14.

As shown in FIGS. 1 and 3, the substrate 16 includes a substrate body 17, mounting

electrodes

28 and 30,

external electrodes

32 and 34, and via-hole conductors v2 and v3. The substrate body 17 is a flat plate having a rectangular shape when viewed from above, and has an upper surface and a lower surface. A recess G 3 is provided on the upper surface of the substrate body 17. The recess G3 has a rectangular shape with long sides extending in the left-right direction when viewed from above. Examples of the material of the substrate body 17 include ceramic insulating materials such as an aluminum oxide sintered body, a mullite sintered body, an aluminum nitride sintered body, a silicon carbide sintered body, and a glass ceramic sintered body, Glass, silicon and the like.

The mounting electrode 28 is provided on the upper surface of the substrate body 17 and is adjacent to the center of the short side on the left side of the recess G3 when viewed from above. The mounting electrode 30 is provided on the upper surface of the substrate body 17 and is adjacent to the center of the short side on the right side of the recess G3 when viewed from above.

The external electrode 32 is a rectangular conductor which is provided on the lower surface of the substrate body 17 and is adjacent to the left short side of the substrate body 17 when viewed from below. The external electrode 34 is provided on the lower surface of the substrate body 17 and is a rectangular conductor adjacent to the right short side of the substrate body 17 when viewed from below. The

external electrodes

32 and 34 have, for example, a configuration in which an Au layer is provided on a Cr underlayer by a plating method.

The via-hole conductor v2 penetrates the substrate body 17 in the vertical direction, and connects the mounting electrode 28 and the external electrode 32. The via-hole conductor v3 penetrates the substrate body 17 in the vertical direction, and connects the mounting electrode 30 and the external electrode 34. The via-hole conductors v2 and v3 have a configuration in which, for example, a conductive paste containing Ag and AgPd is filled in the via-hole and then sintered.

The crystal resonator element 13 is mounted on the upper surface of the substrate 16. Specifically, the pad electrode 39 is connected to the mounting electrode 28 by solder or the like. Thereby, the excitation electrode 20 and the external electrode 32 are connected via the extraction electrode 24, the via-hole conductor v1, the pad electrode 39, the mounting electrode 28, and the via-hole conductor v2. The right end of the extraction electrode 26 is connected to the mounting electrode 30 by solder or the like. Thereby, the excitation electrode 22 and the external electrode 34 are connected via the extraction electrode 26, the mounting electrode 30, and the via-hole conductor v3.

Further, a bonding material 38 is provided on the lower surface of the crystal piece 14. The bonding material 38 bonds the outer edge of the lower surface of the crystal piece 14 and the outer edge of the upper surface of the substrate body 17. However, since the recess G 3 is provided on the upper surface of the substrate body 17, the substrate body 17 is not in contact with the excitation electrode 22. Therefore, the substrate body 17 does not hinder the vibration of the crystal piece 14.

(effect)
According to the crystal resonator element 13 configured as described above, an increase in capacitance between the excitation electrode 20 and the excitation electrode 22 can be suppressed. More specifically, in the crystal resonator element 13, the via-hole conductor v1 is connected to the extraction electrode 24 and penetrates the crystal piece 14 so as to connect the upper surface and the lower surface. The right half of the via-hole conductor v1 is positioned at the connecting portion 14d when viewed from above, and the left half of the via-hole conductor v1 is positioned at the frame portion 14c when viewed from above. Therefore, when viewed from above, the via-hole conductor v1 is positioned in the vicinity of the inner peripheral portion of the frame portion 14c and is not positioned in the vicinity of the outer peripheral portion of the frame portion 14c. The bonding material 36 is along the outer peripheral portion of the frame portion 14c when viewed from above. Therefore, the contact of the via-hole conductor v1 and the extraction electrode 24 with the bonding material 36 and the cap 12 is suppressed. As a result, the conduction between the excitation electrode 20 and the bonding material 36 is suppressed, and the capacitance between the bonding material 36 and the bonding material 38 is added to the capacitance between the excitation electrode 20 and the excitation electrode 22. Is suppressed. As described above, according to the crystal resonator element 13, it is possible to suppress an increase in capacitance added to the capacitance between the excitation electrode 20 and the excitation electrode 22. And the power consumption resulting from the vibration efficiency of the crystal vibration element 13 is suppressed, and the influence of the electromagnetic noise from the outside is reduced.

Here, the relationship between the increase in capacitance added to the capacitance of the crystal resonator element and the decrease in vibration efficiency of the crystal resonator element 13 will be described. An equivalent circuit of the crystal resonator element is approximated to a system in which an equivalent series capacitance C1, an equivalent series inductance L1, and an equivalent series resistance R1 are connected in series to each other, and an electric system branch of the equivalent parallel capacitance C0 is connected in parallel. To do. At this time, it is known that the following formula (1) is established among the electromechanical coupling constant K, the equivalent parallel capacitance C0, and the equivalent series capacitance C1 in the piezoelectric device using the resonance phenomenon.

K ² ∝C1 / C0 (1)

When the capacitance caused by the bonding material is added to the capacitance between the excitation electrode 20 and the excitation electrode 22, the equivalent parallel capacitance C0 in the equivalent circuit of the crystal resonator increases. Thereby, the electromechanical coupling constant K shown by Formula (1) reduces. As a result, the vibration efficiency of the crystal resonator element 13 is reduced. Therefore, in the crystal resonator element 13, when an increase in capacitance added to the capacitance between the excitation electrode 20 and the excitation electrode 22 is suppressed, a decrease in vibration efficiency of the crystal resonator element 13 is suppressed. .

Further, according to the crystal resonator element 13, it is possible to suppress the vibration from leaking out of the vibrating portion 14a. More specifically, in the crystal resonator element 13, the right half of the via-hole conductor v1 is located at the connecting portion 14d when viewed from above. As a result, the acoustic impedance changes in the portion of the connecting portion 14d where the via-hole conductor v1 is provided. Therefore, even if the vibration generated in the vibration part 14a is transmitted through the connecting part 14d and leaks to the frame part 14c, it is reflected to the vibration part 14a side in the via-hole conductor v1. As a result, according to the crystal resonator element 13, it is possible to suppress vibration from leaking out of the vibrating portion 14 a.

Further, according to the crystal resonator element 13, the right half of the via-hole conductor v 1 is located at the connecting portion 14 d when viewed from above, so that the via-hole conductor v 1 is positioned closer to the center of the crystal resonator element 13. It becomes like this. As a result, according to the crystal resonator element 13, the element can be miniaturized.

Further, according to the crystal resonator element 13, the via-hole conductor v1 has a structure in which the through hole is filled with the conductor. Therefore, the direct current resistance value of the via-hole conductor v1 is reduced. Furthermore, occurrence of disconnection of the via-hole conductor v1 is suppressed.

Further, according to the crystal resonator element 13, it is possible to suppress the vibration from leaking out of the vibrating portion 14a. More specifically, in the crystal resonator element 13, the flange portion 14b surrounds most of the periphery of the vibrating portion 14a when viewed from above. Moreover, the thickness of the flange part 14b is smaller than the thickness of the vibration part 14a. Thereby, the vibration generated in the vibration part 14a is suppressed from being transmitted to the flange part 14b, and is confined in the vibration part 14a. That is, the leakage of vibrations outside the vibrating portion 14a is suppressed.

Further, according to the crystal resonator element 13, the leakage of vibration outside the vibrating portion 14a is suppressed for the following reason. More specifically, when viewed from above, a portion of the lower surface of the crystal piece 14 that overlaps the connecting portion 14d is depressed as shown in FIG. That is, the recess G2 is provided. Thereby, the thickness of the part in which the connection part 14d was provided in the crystal piece 14 becomes small. As a result, the leakage of vibration from the portion of the crystal piece 14 where the connecting portion 14d is provided to the outside of the vibrating portion 14a is suppressed. For the same reason, the leakage of vibration from the portion of the crystal piece 14 where the connecting portion 14e is provided to the outside of the vibrating portion 14a is suppressed.

(First modification)
Hereinafter, a crystal resonator 10a including the crystal resonator element 13a according to the first modification will be described with reference to the drawings. FIG. 5 is an exploded perspective view of the crystal unit 10a. FIG. 6 is an external perspective view of the crystal resonator element 13a as viewed from below.

The crystal resonator element 13a is different from the crystal resonator element 13 at a position where the connecting

portions

14d and 14e are provided. Hereinafter, the crystal resonator element 13a will be described focusing on the difference.

In the crystal resonator element 13a, the connecting

portions

14d and 14e are connected to the diagonal of the vibrating portion 14a when viewed from above. More specifically, when viewed from above, the connecting portion 14d connects the left rear corner of the vibrating portion 14a and the left rear corner of the inner peripheral portion of the frame portion 14c. When viewed from above, the connecting portion 14e connects the right front corner of the vibrating portion 14a and the right front corner of the inner peripheral portion of the frame portion 14c.

Further, the extraction electrode 24 is connected to the left rear corner of the excitation electrode 20 and is provided on the upper surface of the coupling portion 14d. The via hole conductor v 1 is provided at the boundary between the connecting portion 14 d and the frame portion 14 c and is connected to the extraction electrode 24.

Further, the extraction electrode 26 is connected to the right front corner of the excitation electrode 20 and is provided on the upper surface of the coupling portion 14e. In addition, since the other structure of the crystal oscillation element 13a is the same as the crystal oscillation element 13, description is abbreviate | omitted.

According to the crystal resonator element 13 a configured as described above, an increase in capacitance between the excitation electrode 20 and the excitation electrode 22 can be suppressed for the same reason as the crystal resonator element 13. Further, according to the crystal resonator element 13a, the leakage of the vibration to the outside of the vibration portion 14a is suppressed for the same reason as the crystal resonator element 13. Further, according to the crystal resonator element 13a, the element can be miniaturized for the same reason as the crystal resonator element 13. According to the crystal resonator element 13a, for the same reason as the crystal resonator element 13, the direct current resistance value of the via-hole conductor v1 is reduced and the occurrence of disconnection of the via-hole conductor v1 is suppressed.

Further, according to the crystal resonator element 13a, the connecting

portions

14d and 14e are connected to the diagonal of the vibrating portion 14a when viewed from above. An AT-cut quartz piece generally used as a quartz oscillator causes a frequency change proportional to external stress. The magnitude of the change depends on the angle with respect to the crystal crystal axis in the direction in which stress is applied, and is the smallest on the crystal axis rotated 60 degrees from the X direction. The long side direction of a typical crystal resonator element is the X direction. With the diagonal connection, the stress applied from the connecting

portions

14d and 14e to the vibrating portion 14a can be rotated from the X direction, so that the influence of the stress on the vibration frequency can be reduced.

(Second modification)
Hereinafter, a crystal resonator 10b including the crystal resonator element 13b according to the second modification will be described with reference to the drawings. FIG. 7 is an exploded perspective view of the crystal unit 10b. FIG. 8 is an external perspective view of the crystal resonator element 13b as viewed from below.

The crystal resonator element 13b is different from the crystal resonator element 13 in the position where the connecting

portions

14d and 14e are provided. Hereinafter, the crystal resonator element 13b will be described focusing on the difference.

In the crystal resonator element 13b, the connecting

portions

14d and 14e are connected to the short side on the left side of the vibrating portion 14a when viewed from above. More specifically, the connecting portion 14d is connected slightly to the rear side with respect to the center of the short side on the left side of the vibrating portion 14a when viewed from above. The connection part 14e is slightly connected to the front side with respect to the center of the short side on the left side of the vibration part 14a when viewed from below. Thereby, the connection part 14d and the connection part 14e are slightly shifted in the front-back direction when viewed from above.

Further, the extraction electrode 24 is connected to the left short side of the excitation electrode 20 and is provided on the upper surface of the coupling portion 14d. The via hole conductor v 1 is provided at the boundary between the connecting portion 14 d and the frame portion 14 c and is connected to the extraction electrode 24.

Further, the extraction electrode 26 is connected to the left short side of the excitation electrode 20 and is provided on the upper surface of the coupling portion 14e.

The position where the via-hole conductor v3 is provided on the substrate 16b is the same as the position where the via-hole conductor v3 is provided on the substrate 16. Therefore, the left end of the extraction electrode 26 and the via-hole conductor v3 are greatly separated. Therefore, in the substrate 16b, the mounting electrode 30 extends along the outer edge of the recess G3 from the vicinity of the center of the short side on the left side of the recess G3 to the vicinity of the center of the short side on the right side of the recess G3 when viewed from above. Yes. Thereby, the mounting electrode 30 connects the left end of the extraction electrode 26 and the via-hole conductor v3. In addition, since the other structure of the crystal oscillation element 13b is the same as the crystal oscillation element 13, description is abbreviate | omitted.

According to the crystal resonator element 13b configured as described above, an increase in the capacitance between the excitation electrode 20 and the excitation electrode 22 can be suppressed for the same reason as the crystal resonator element 13. Further, according to the crystal resonator element 13b, the leakage of vibration outside the vibrating portion 14a is suppressed for the same reason as the crystal resonator element 13. Further, according to the crystal resonator element 13b, the element can be miniaturized for the same reason as the crystal resonator element 13. According to the crystal resonator element 13b, for the same reason as the crystal resonator element 13, the direct current resistance value of the via-hole conductor v1 is reduced and the occurrence of disconnection of the via-hole conductor v1 is suppressed.

(Third Modification)
Hereinafter, a crystal resonator 10c including a crystal resonator element 13c according to a third modification will be described with reference to the drawings. FIG. 9 is an exploded perspective view of the crystal unit 10c. A perspective view of the crystal resonator element 13c as viewed from below is the same as the crystal resonator element 13, and therefore FIG.

The crystal resonator element 13c is different from the crystal resonator element 13 in the line width of the connecting portion 14d. Hereinafter, the crystal resonator element 13c will be described focusing on the difference.

In the crystal resonator element 13c, the line width of the connecting portion 14d is larger than the line width of the connecting portion 14e. The line width of the connecting portion 14d means a width in a direction orthogonal to the direction in which the connecting portion 14d extends (that is, the front-rear direction) when viewed from above. The line width of the connecting portion 14e means a width in a direction perpendicular to the direction in which the connecting portion 14e extends (that is, the front-rear direction) when viewed from above.

According to the crystal resonator element 13c configured as described above, an increase in capacitance between the excitation electrode 20 and the excitation electrode 22 can be suppressed for the same reason as the crystal resonator element 13. Further, according to the crystal resonator element 13c, the leakage of vibration to the outside of the vibration portion 14a is suppressed for the same reason as the crystal resonator element 13. Further, according to the crystal resonator element 13c, the element can be miniaturized for the same reason as the crystal resonator element 13. According to the crystal resonator element 13c, for the same reason as the crystal resonator element 13, the direct-current resistance value of the via-hole conductor v1 is reduced and the occurrence of disconnection of the via-hole conductor v1 is suppressed.

Further, according to the crystal resonator element 13c, the via-hole conductor v1 can be thickened. More specifically, a part of the via-hole conductor v1 is provided in the connecting portion 14d. Thereby, it is suppressed that the vibration which generate | occur | produced in the vibration part 14a leaks to the frame part 14c via the connection part 14d. Therefore, the leakage of vibration is less likely to occur in the connecting portion 14d where the via-hole conductor v1 is provided than in the connecting portion 14e where the via-hole conductor is not provided. Therefore, even if the line width of the connecting portion 14d is increased, it is easy to suppress the amount of vibration leakage from the connecting portion 14d to be equal to the amount of vibration leakage from the connecting portion 14e. Then, by increasing the line width of the connecting portion 14d, the via-hole conductor v1 can be increased. As a result, the direct current resistance value of the via-hole conductor v1 is reduced. Further, since the via hole conductor is not provided in the connecting portion 14e, the leakage of vibration from the vibrating portion 14a to the frame portion 14c is suppressed by reducing the line width of the connecting portion 14e.

(Other embodiments)
The piezoelectric resonator element according to the present invention is not limited to the crystal resonator elements 13, 13a to 13c, and can be changed within the scope of the gist thereof.

Note that the configurations of the crystal resonator elements 13 and 13a to 13c may be arbitrarily combined.

Further, a part of the via-hole conductor v1 is located at the connecting portion 14d when viewed from the upper side. However, the entire via-hole conductor v1 may be located at the connecting portion 14d when viewed from above. Thereby, the vibration generated in the vibration part 14a is effectively reflected by the via hole conductor v1 on the vibration part 14a side. As a result, the leakage of vibration from the vibrating portion 14a to the frame portion 14c is more effectively suppressed.

Further, although the crystal piece 14 is an AT-cut crystal piece, it may be a BT-cut crystal piece that vibrates in the thickness-slip mode in the same manner. Further, instead of the crystal piece 14, a piezoelectric piece including lithium tantalate, lithium niobate, or piezoelectric ceramic may be used.

In addition, the vibration part 14a of the crystal piece 14 may have a so-called mesa structure. That is, the thickness of the outer edge of the vibrating portion 14a may be smaller than the thickness of the portion excluding the outer edge of the vibrating portion 14a. Thereby, it is suppressed more effectively that a vibration leaks from the vibration part 14a.

As described above, the present invention is useful for piezoelectric vibration elements, and is particularly excellent in that an increase in capacitance can be suppressed.

10, 10a to 10c: Crystal resonator 12: Cap 13, 13a to 13c: Crystal vibrating element 14: Crystal piece 14a: Vibrating portion 14b: Flange portion 14c:

Frame portion

14d, 14e: Connecting

portion

16, 16b: Substrate 17: Substrate bodies 20, 22: Excitation electrodes 24, 26: Lead electrodes 36, 38: Bonding material 39: Pad electrodes G1 to G3: Recesses v1 to v3: Via hole conductors

Claims

A piezoelectric vibration element including a piezoelectric piece having a first main surface and a second main surface, a first excitation electrode, a second excitation electrode, a first extraction electrode, and a through conductor. There,
The piezoelectric piece is
A vibrating part;
When viewed from the normal direction of the first main surface, a frame portion that surrounds the periphery of the vibration portion away from the vibration portion and has a thickness equal to or greater than the thickness of the vibration portion;
A first connecting part that connects the vibrating part and the frame part when viewed from the normal direction of the first main surface;
Contains
There is no step between the first main surface of the vibrating portion and the first main surface of the first connecting portion,
There is no step between the first main surface of the frame portion and the first main surface of the first connecting portion,
The first excitation electrode is provided on the first main surface of the vibration part,
The second excitation electrode is provided on the second main surface of the vibrating part,
The first extraction electrode is connected to the first excitation electrode and provided on the first main surface of the first coupling portion;
The through conductor is connected to the first lead electrode and penetrates the piezoelectric piece so as to connect the first main surface and the second main surface,
At least a part of the through conductor is located in the first connecting portion when viewed from the normal direction of the first main surface;
A piezoelectric vibration element characterized by the above.
The through conductor has a structure in which a through hole penetrating the piezoelectric piece is filled with a conductor,
The piezoelectric vibration element according to claim 1.
A part of the through conductor is located in the first connecting portion when viewed from the normal direction of the first main surface;
The piezoelectric vibration element according to claim 1, wherein:
The entire through conductor is located in the first connecting portion when viewed from the normal direction of the first main surface;
The piezoelectric vibration element according to claim 1, wherein:
The second extraction electrode,
In addition,
The piezoelectric piece further includes a second connecting portion that connects the vibrating portion and the frame portion when viewed from the normal direction of the second main surface,
There is no step between the second main surface of the vibrating portion and the second main surface of the second connecting portion,
There is no step between the second main surface of the frame portion and the second main surface of the second connecting portion,
The second extraction electrode is connected to the second excitation electrode and provided on the second main surface of the second coupling portion;
The line width of the first connecting portion when viewed from the normal direction of the first main surface is the line width of the second connecting portion when viewed from the normal direction of the second main surface. Is thicker than
The piezoelectric vibration element according to claim 1, wherein:
The piezoelectric piece is
A flange portion provided between the vibrating portion and the frame portion when viewed from the normal direction of the first main surface, the flange portion having a thickness smaller than the thickness of the vibrating portion The
In addition,
The first main surface of the piezoelectric piece is recessed in the flange portion;
The piezoelectric vibration element according to claim 1, wherein:
The piezoelectric piece is
A flange portion provided between the vibrating portion and the frame portion when viewed from the normal direction of the first main surface, the flange portion having a thickness smaller than the thickness of the vibrating portion The
In addition,
The second main surface of the piezoelectric piece is recessed in the flange portion;
The piezoelectric vibration element according to claim 1, wherein:
When viewed from the normal direction of the first main surface, a portion of the second main surface that overlaps the first connecting portion is depressed,
The piezoelectric vibration element according to claim 6.
The vibrating portion has a rectangular shape when viewed from the normal direction of the first main surface,
The first connecting part and the second connecting part are connected to the diagonal of the vibrating part when viewed from the normal direction of the first main surface;
The piezoelectric vibration element according to claim 5.