JP5468327B2 - Piezoelectric device - Google Patents

Description

  The present invention relates to a piezoelectric device used in electronic equipment.

Conventionally, a wiring board such as a mother board on which electronic components are mounted is used for electronic devices. A conductive pattern made of a metal film is formed on the wiring substrate, and electronic components are mounted on the wiring substrate by bonding chip components such as capacitors to the conductive pattern with solder or the like.
In addition to the chip component, the electronic component includes a piezoelectric vibrator having a structure in which a piezoelectric vibration element including a vibrating portion and a holding portion is sandwiched between a lid member and a substrate member, and such a piezoelectric vibrator. And an electronic component such as a piezoelectric oscillator to which an integrated circuit including at least an oscillation circuit is connected.

Here, the piezoelectric vibrator will be described.
For example, a piezoelectric vibration element used in this piezoelectric vibrator is composed of a frame-shaped holding portion and a vibrating portion that is surrounded by the holding portion and is integrated with the holding portion. This vibrating part is provided with excitation electrodes on both main surfaces. In addition, the holding part is provided with a metal film for bonding on both main surfaces on the outer peripheral edge side, and the mounting terminal is electrically connected to the excitation electrode of the vibration part so as not to be connected to the metal film. Yes.
The substrate member has a recess on one main surface, a metal film for bonding is provided so as to surround the recess, and a connection terminal that is bonded to the mounting terminal so as not to be connected to the metal film Is provided. In addition, a vibrator-side external terminal is provided on the other main surface of the substrate member, and a predetermined vibrator-side external terminal is electrically connected to the connection terminal.
The substrate member configured in this manner is bonded in a state where the metal film is overlapped with the metal film of the piezoelectric vibration element while the concave portion is directed toward the vibration part of the piezoelectric vibration element.
The lid member has a concave portion on one main surface, and a metal film for bonding is provided so as to surround the concave portion.
The lid member configured as described above is bonded in a state where the metal film is overlapped with the metal film of the piezoelectric vibration element while the concave portion is directed toward the vibration part of the piezoelectric vibration element.
Thus, the piezoelectric vibrator is configured (see Patent Document 1).

A case will be described in which the piezoelectric vibrator includes an element mounting member having a recess and a lid.
The element mounting member has a concave portion formed on one main surface, and a metal film is provided on a surface to be joined to a lid member described later. In addition, a piezoelectric vibration element mounting pad for mounting the piezoelectric vibration element is provided inside the metal film. In addition, an external terminal for mounting on a wiring board such as a mother board is provided on the main surface opposite to the main surface on which the metal film is provided. The external terminal is connected to the piezoelectric vibration element mounting pad via an internal wiring pattern. Such an element mounting member becomes a wafer in a state where a plurality of element mounting members are connected. Such a wafer is provided with a metal film, a mounting pad, and an external terminal at a portion to be an element mounting member.
In addition, the lid member is provided with a recess having a size capable of sealing the piezoelectric vibration element inside, and a metal film made of a sealing material is provided on a surface to be bonded to the element mounting member. Yes. Such a lid member is a wafer in a state where a plurality of lid members are connected. Such a wafer is provided with a metal film at a portion to be a lid member.

Here, the piezoelectric vibrator is manufactured through the following steps.
First, the piezoelectric vibration element is mounted on the piezoelectric vibration element mounting pad provided on the element mounting member via a conductive adhesive, and the lid member is mounted so that the piezoelectric vibration element enters the recess of the lid member in this state. Overlay the member.
In a state where the element mounting member and the lid member are overlapped, for example, heating at 300 ° C. to 350 ° C., joining the element mounting member and the lid member, and providing a plurality of piezoelectric vibrators on one wafer To.
Thereafter, the piezoelectric vibrator is cut into individual pieces by cutting at the boundaries between the piezoelectric vibrators (see, for example, Patent Document 2).

In addition, a piezoelectric vibrator having a similar structure in which an element mounting member in a wafer state and a lid member are joined without using a metal film for joining has been proposed (for example, see Patent Document 3). ).
The element mounting member and the lid member are joined by direct joining. The temperature at which this bonding is performed is set to 200 ° C to 500 ° C.
In this way, bonding is performed in the state of a wafer, and the piezoelectric vibrators are cut into pieces and cut into individual piezoelectric vibrators.

By the way, while electronic devices are being miniaturized, various proposals have been made so that electronic components used in the electronic devices can cope with the miniaturization.
For example, in the case of a piezoelectric vibrator, a piezoelectric vibrator as shown in Patent Document 4 has been proposed.
In this piezoelectric vibrator, the element mounting member on which the piezoelectric vibration element is mounted is formed to have a larger plane area than the lid member. In this element mounting member, a lid member is joined to one main surface, and an external terminal is provided on the remaining portion of the one main surface. For example, the external terminals are joined and electrically connected to a mother board or the like using a conductive adhesive or solder.
When the piezoelectric vibrator having such a structure is mounted on a mother board, an opening having a size surrounding the lid member is formed in the mother board, and a connection terminal corresponding to an external terminal provided on the piezoelectric vibrator. Is provided around the opening.
Accordingly, the piezoelectric vibrator is used by joining the external terminal to the connection terminal of the motherboard in a state where the lid member of the piezoelectric vibrator is inserted into the opening of the motherboard.
Thereby, even if it becomes the structure of the piezoelectric vibrator of the state which the cover member protruded, it can mount in a motherboard.

JP 2007-096777 A JP 2006-279872 A JP 2006-339896 A JP 2008-252467 A

Conventional piezoelectric vibrators may use quartz or glass for a substrate member or an element mounting member.
For example, in the case of a piezoelectric vibrator as proposed in Patent Document 1, a lid member and a substrate member are formed of quartz as the same material as the piezoelectric vibration element in order to facilitate manufacture. This is to reduce the influence of distortion caused by heat at the time of joining by using a material that is the same as or close to the thermal expansion coefficient of the material used for the piezoelectric vibration element for the substrate member or the element mounting member. . However, when the same material as the piezoelectric vibration element is used for the substrate member and the element mounting member, the substrate member and the element mounting member are weak against impact and may be damaged.
Further, when ceramic is used for the substrate member as a material different from the piezoelectric vibration element in order to cope with the impact, the substrate member is deformed by heat due to the difference in thermal expansion coefficient of the material used for the piezoelectric vibration element, and the piezoelectric member There is also a possibility of affecting the frequency of the vibration element.

  Therefore, an object of the present invention is to provide a piezoelectric device that solves the above-described problems and prevents damage when subjected to an impact.

In order to solve the above-mentioned problems, the present invention provides a piezoelectric vibration element comprising a vibration part having a pair of excitation electrodes and a holding part having a pair of mounting terminals that are electrically connected to the excitation electrodes. Piezoelectric vibration in which the piezoelectric vibrator side external terminal provided on the substrate member and the mounting terminal provided on the piezoelectric vibration element are electrically connected by being sandwiched between the member and a lid member having a recess and children, is formed in a flat plate shape, the pair of the piezoelectric vibrator mounting pad piezoelectric vibrator is mounted a piezoelectric vibrator connected to an external terminal which is electrically connected to the piezoelectric vibrator mounting pads least two pairs And an external terminal for mounting of the module board provided on one main surface, and one main surface of the module board faces the wiring board when mounted on an external wiring board, And piezoelectric vibrator contact The bumps on the external terminal said and mounting an external terminal is thicker than the piezoelectric vibrator is provided, a piezoelectric device, wherein the bumps are bonded to the connection terminals provided on said wiring board.

  According to such a piezoelectric device, since the module substrate is positioned outside the piezoelectric vibrator, the module substrate receives an impact from the outside, and the piezoelectric vibrator can be prevented from being damaged.

It is a conceptual diagram which shows an example of the piezoelectric device which concerns on embodiment of this invention. It is a disassembled perspective view which shows an example of the piezoelectric device which concerns on embodiment of this invention. It is a perspective view which shows an example of a board | substrate member. It is a conceptual diagram which shows an example of the state which mounted the piezoelectric device which concerns on embodiment of this invention in the wiring board. It is a perspective view which shows an example of the element mounting member used for the modification of the piezoelectric device which concerns on embodiment of this invention.

  Next, the best mode for carrying out the present invention (hereinafter referred to as “embodiment”) will be described in detail with reference to the drawings as appropriate. Note that each component is exaggerated for easy understanding of the state.

FIG. 1 is a conceptual diagram illustrating an example of a piezoelectric device according to an embodiment of the present invention. FIG. 2 is an exploded perspective view showing an example of the piezoelectric device according to the embodiment of the present invention. FIG. 3 is a perspective view showing an example of the substrate member. FIG. 4 is a conceptual diagram showing an example of a state in which the piezoelectric device according to the embodiment of the present invention is mounted on a wiring board.
As shown in FIGS. 1 to 3, the piezoelectric device 100 according to the embodiment of the present invention is mainly composed of a module substrate 10 and a piezoelectric vibrator 20 </ b> A.

As shown in FIGS. 1 to 3, the module substrate 10 is provided with a piezoelectric vibrator mounting pad 11 </ b> A, a piezoelectric vibrator connection external terminal 11 </ b> B, a piezoelectric vibrator holding pad 12, and a mounting external terminal 13 on one main surface. It has been.
The module substrate 10 is a plate-like member formed in a square shape in plan view, and is formed using a material such as ceramic or glass ceramic, for example. As shown in FIG. 2, in order to join the piezoelectric vibrator 20, two main pairs of piezoelectric vibrator mounting pads 11 </ b> A are arranged on one main surface of the module substrate 10 so as to face the piezoelectric vibrator 20. The two piezoelectric vibrator holding pads 12 are provided side by side at a position away from the piezoelectric vibrator mounting pad 11A. In addition, on one main surface of the module substrate 10, the piezoelectric vibrator connection external terminal 11 </ b> B and the mounting external terminal 13 are provided on the other surface not facing the piezoelectric vibrator 20 and on the edge side of the module board 10. .

The piezoelectric vibrator connection external terminal 11B is provided, for example, on the corner side of the module substrate 10 closest to the piezoelectric vibrator mounting pad 11A. That is, when each of the piezoelectric vibrator connection external terminals 11B is provided with two pairs of piezoelectric vibrator mounting pads 11A arranged side by side at two adjacent corners of the four corners of the module substrate 10, these piezoelectric vibrators are connected. It is provided so as to be positioned near the mounting pad 11 </ b> A and on the corner side of the module substrate 10.
As shown in FIG. 4, the piezoelectric vibrator connection external terminal 11B is used for mounting on the wiring board MB used in the electronic device in a state of being connected to the piezoelectric vibrator mounting pad 11A.

  The mounting external terminals 13 are respectively provided on the remaining corners of the module substrate 10. The mounting external terminals 13 are, for example, a pair of two, and are used for mounting on the wiring board MB used in the electronic device.

  The piezoelectric vibrator 20 mainly includes a piezoelectric vibration element 21, a lid member 22, and a substrate member 23.

In the piezoelectric vibration element 21, the vibration part 21 </ b> A and the holding part 21 </ b> B are integrally formed. For example, the excitation electrode 21 </ b> C is provided on both main surfaces of the piezoelectric piece having a rectangular shape in plan view so as to surround the piezoelectric piece. A mounting terminal 21D is provided on the annular holding portion 21B formed in the above, and an annular metal film 21E is provided on the edge portion of the holding portion 21B. For the piezoelectric piece, a piezoelectric material such as quartz is used.
Each excitation electrode 21C is configured to be electrically connected to each mounting terminal 21D and not electrically connected to the metal film 21E.
The metal film 21E is provided on both main surfaces of the frame portion 21B, and is used for joining a substrate member 23 and a lid member 22 described later.

  The lid member 22 has a recess 22A on one main surface, and is formed to have the same plane area as that of the piezoelectric vibration element 21. The lid member 22 is provided with a metal film (not shown) on the edge portion of the lid member 22 so as to surround the recess 22A.

The substrate member 23 has a recess 23 </ b> A on one main surface and is formed to have the same plane area as that of the piezoelectric vibration element 21. This substrate member 23 is provided with a metal film 23C on the edge portion of the substrate member 23 so as to surround the recess 23A, and is connected to the mounting terminal 21D closer to the recess 22A than the metal film 23C. A terminal 23B is provided.
The substrate member 23 is provided with a piezoelectric vibrator side external terminal 23D on the other main surface.
The piezoelectric vibrator side external terminals 23D are provided at the four corners of the substrate member 23, respectively.
The predetermined piezoelectric vibrator side external terminal 23D is electrically connected to the piezoelectric vibration element connection terminal 23B.
These piezoelectric vibrator side external terminals 23 </ b> D are used for joining the piezoelectric vibrator mounting pad 11 </ b> A provided on the module substrate 10 and the piezoelectric vibrator holding pad 12.

  The piezoelectric vibrator 20A configured as described above has the piezoelectric vibration element 21 sandwiched between the lid member 22 and the substrate member 23, and the metal film 21E of the piezoelectric vibration element 21 and the metal film of the lid member 22 are overlapped. They are joined together. That is, when the piezoelectric vibrator 20A is manufactured, first, the metal film 21E of the piezoelectric vibration element 21 and the metal film 23C of the substrate member 23 are overlapped. Thereafter, the overlapped metal films are bonded to each other in, for example, a vacuum atmosphere by using conventionally known direct bonding or anodic bonding. Thereby, the piezoelectric vibrator 20A is manufactured.

This will be described in detail below.
The piezoelectric vibration element 21 forms a wafer (not shown) in a state where a plurality of the piezoelectric vibration elements 21 are connected, and a metal film 21E is provided on a portion of the wafer that becomes the piezoelectric vibration element 21.
The lid member 22 forms a wafer (not shown) in a state where a plurality of lid members 22 are connected to each other, and a metal film (not shown) is provided on the portion of the wafer that becomes the lid member 22.
Furthermore, the substrate member 23 forms a wafer (not shown) in a state where a plurality of substrate members are connected, and a metal film 23 </ b> C is provided on a portion to be the substrate member 23 of the wafer.

  Among the wafers formed in this way, the wafers are stacked so that the metal film 21E of the wafer having the portion to be the piezoelectric vibration element 21 and the metal film of the wafer having the portion to be the cover member 22 are stacked. In addition, the wafers are overlapped so that the metal film 21E of the wafer having the portion to be the piezoelectric vibration element 21 and the metal film 23C of the wafer having the portion to be the substrate member 23 are overlapped. In this state, the wafers are bonded together by a well-known direct bonding or anodic bonding. In this state, the integrated wafer is in a state in which portions to be a plurality of piezoelectric vibrators 20A are connected. Thereafter, cutting is performed at the boundary between the portions to be the piezoelectric vibrators 20A to form individual piezoelectric vibrators 20A.

Therefore, the piezoelectric device 100 according to the embodiment of the present invention is configured by mounting the piezoelectric vibrator 20 </ b> A configured as described above on the module substrate 10.
Specifically, each piezoelectric vibrator side external terminal 23D provided on the substrate member 23 of the piezoelectric vibrator 20A is soldered to the piezoelectric vibrator mounting pad 11A and the piezoelectric vibrator holding pad 12 provided on the module substrate 10. The piezoelectric vibrator 20A is mounted on the module substrate 10 by bonding using a conductive adhesive or the piezoelectric device 100 according to the embodiment of the present invention.

  In addition, the piezoelectric device 100 is provided on the wiring board MB by providing bumps thicker than the piezoelectric vibrator 20A on the piezoelectric vibrator connection external terminals 11B and the mounting external terminals 13 provided on the module substrate 10. It is mounted on the wiring board MB by bonding to a connecting terminal (not shown). The wiring board MB is formed with a recess that can be inserted into the piezoelectric vibrator 20A, and a connection terminal that is joined to the piezoelectric vibrator connection external terminal 11B and the mounting external terminal 13 is provided around the recess. May be configured.

Thus, after mounting the piezoelectric device 100 according to the embodiment of the present invention on the wiring board MB, the module substrate 10 is located on the outside, so that the module substrate receives an impact, and the piezoelectric vibrator 20A is impacted. Can be protected from.
That is, the piezoelectric device 100 according to the embodiment of the present invention can prevent the piezoelectric vibrator from being damaged even when an impact is applied.

(Modification)
As shown in FIG. 5, the modification of the piezoelectric device according to the embodiment of the present invention has a structure in which the piezoelectric vibration element 24 of the piezoelectric vibrator 20 </ b> B has a recess inside the plate-like piezoelectric piece.

Here, the piezoelectric vibrator 20 </ b> B mainly includes a piezoelectric vibration element 24, a lid member 25, and a substrate member 26.
The piezoelectric vibration element 24 is formed thinner than the outer peripheral portion with a recess 24A provided in the central portion of the piezoelectric piece.
In addition, excitation electrodes 24B are provided on both main surfaces of the piezoelectric piece in the recess 24A of the piezoelectric piece.
A metal film 24D is provided on the edge portion of the piezoelectric piece so as to surround the recess 24A, and a mounting terminal 24C is provided so as not to be connected to the metal film 24D.
The mounting terminal 24C and the excitation electrode 24B are in an electrically connected state.

  The lid member 25 has a recess 25 </ b> A on one main surface and is formed to have the same plane area as that of the piezoelectric vibration element 24. The lid member 25 is provided with a metal film (not shown) on the edge portion of the lid member 25 so as to surround the recess 25A.

The substrate member 26 has a concave portion 26 </ b> A on one main surface and is formed to have the same plane area as the piezoelectric vibration element 24. The substrate member 26 is provided with a metal film 26C at an edge portion of the substrate member 26 so as to surround the recess 26A, and is connected to the mounting terminal 24C closer to the recess 26A than the metal film 26C. A terminal 26B is provided.
The substrate member 26 is provided with a piezoelectric vibrator side external terminal 26D on the other main surface.
The piezoelectric vibrator side external terminals 26D are provided at the four corners of the substrate member 26, respectively.
The predetermined piezoelectric vibrator side external terminal 26D is electrically connected to the piezoelectric vibration element connection terminal 26B.
These piezoelectric vibrator side external terminals 26 </ b> D are used for joining the piezoelectric vibrator mounting pad 11 </ b> A provided on the module substrate 10 and the piezoelectric vibrator holding pad 12.
Even if the piezoelectric vibration element 20B is configured in this manner, the same effects as those of the above-described embodiment can be obtained.

In addition, although embodiment of this invention was described, this invention is not limited to the said embodiment. For example, the conductive pattern has the same effect as the present invention no matter how it is routed.
In addition to quartz, the piezoelectric vibration element can use a piezoelectric material such as piezoelectric ceramic or lithium tantalate.
In addition to the flat plate shape, the piezoelectric vibration element has a structure in which a concave portion is formed on a piezoelectric piece to become a vibrating portion, a structure in which a convex portion is formed on a piezoelectric piece to become a vibrating portion, a disk shape, A structure that is formed in a tuning fork type or the like to be a vibrating portion can be used.
When quartz is used for the piezoelectric vibration element, quartz pieces having various cut angles such as AT cut and ST cut can be used as the piezoelectric pieces.

  In addition to the embodiment of the present invention, for example, the lid member 22 of the piezoelectric vibrator 20A and the module substrate 10 are joined with an adhesive, and electrically connected to the piezoelectric vibration element connection terminal 23B of the substrate member 23. Even if the piezoelectric vibrator-side external terminal 23D and the piezoelectric vibrator connection external terminal 11B of the module substrate 10 are connected by wire bonding, the same effects as those of the above embodiment can be obtained.

Further, in addition to the embodiment of the present invention, for example, a recess having a size enough to accommodate the piezoelectric vibrator 20A is formed in the module substrate, and the piezoelectric vibrator 20A is mounted in the recess. The same effect is produced.
In this case, for example, the piezoelectric vibrator mounting pad 11A may be provided in the recess and electrically connected to the piezoelectric vibrator connecting external terminal 11B by internal wiring or surface routing.
It goes without saying that the wiring routing can be changed as appropriate.

DESCRIPTION OF SYMBOLS 100 Piezoelectric device 10 Module board | substrate 11A Piezoelectric vibrator mounting pad 11B Piezoelectric vibrator connection external terminal 12 Piezoelectric vibrator holding pad 13 Mounting external terminal 20A, 20B Piezoelectric vibrator 21, 24 Piezoelectric vibration element 21C, 24B Excitation electrode 21A Vibration part 21B Holding part 12D, 24C Mounting terminal 21E, 23C, 24D, 26C Metal film 22, 25 Lid member 22A, 23A, 24A, 25A, 26A Recess 23, 26 Substrate member 23B, 26B Piezoelectric vibration element connection terminal 23D, 26D Piezoelectric External terminal on transducer side

Claims (1)

A piezoelectric vibration element including a vibrating portion having a pair of excitation electrodes and a holding portion having a pair of mounting terminals electrically connected to the excitation electrodes is sandwiched between a substrate member having a recess and a lid member having a recess. A piezoelectric vibrator bonded and electrically connected to the piezoelectric vibrator side external terminal provided on the substrate member and the mounting terminal provided on the piezoelectric vibration element;
Formed in a plate shape, the pair of the piezoelectric vibrator mounting pad piezoelectric vibrator is mounted a piezoelectric vibrator connected to an external terminal which is electrically connected to the piezoelectric vibrator mounting pads least two a pair of mounting An external terminal, a module substrate provided on one main surface;
Equipped with a,
One main surface of the module board faces the wiring board when mounted on an external wiring board, and the piezoelectric vibrator connection external terminal and the mounting external terminal are thicker than the piezoelectric vibrator. A piezoelectric device comprising: a bump, wherein the bump is bonded to a connection terminal provided on the wiring board .

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