JP2022038696A - Piezoelectric vibration device - Google Patents

Abstract

To provide an inexpensive piezoelectric vibration device.SOLUTION: A piezoelectric vibration device has first and second excitation electrodes on both main surfaces, a piezoelectric diaphragm having first and second metal films connected to each of the first and second excitation electrodes, and first and second sealing members joined to both of the main surfaces of the piezoelectric diaphragm so as to cover each of the first and second excitation electrodes of the piezoelectric diaphragm, in which at least one sealing member of the first and second sealing members is a resin film 3, and a distance D1 between a virtual extension face VF obtained by extending a main surface of an outer frame part joined to the resin film 3 to a position facing the first excitation electrode 25 and the first excitation electrode 25 exceeds a flexure amount D2 of the resin film 3.SELECTED DRAWING: Figure 8

Description

The present invention relates to piezoelectric vibration devices such as piezoelectric vibrators.

Surface mount type crystal oscillators are widely used as piezoelectric vibration devices, for example, as piezoelectric oscillators. As described in Patent Document 1, for example, this surface-mounted crystal unit is derived from the excitation electrodes on both sides of the crystal vibrating piece to the holding electrode in the box-shaped base having an open upper surface made of ceramic. The crystal vibrating piece is housed and mounted in the base by fixing the electrode to the electrode with a conductive adhesive. In this way, the lid is joined to the opening of the base on which the crystal vibrating piece is mounted so as to be airtightly sealed. Further, a mounting terminal for surface mounting the crystal oscillator is formed on the outer bottom surface of the base.

Japanese Unexamined Patent Publication No. 2005-184325

Most of the above-mentioned piezoelectric vibrators have a package made by joining a metal or ceramic lid to a ceramic base, so that the package is expensive and the piezoelectric vibrator is expensive. It has become.

The present invention has been made in view of the above points, and an object of the present invention is to provide an inexpensive piezoelectric vibration device.

In the present invention, in order to achieve the above object, it is configured as follows.

(1) The piezoelectric vibration device according to the present invention has a first excitation electrode formed on one main surface of both main surfaces and a second excitation electrode formed on the other main surface of both main surfaces. The piezoelectric vibrating plate so as to cover the piezoelectric vibrating plate having the first and second metal films connected to the first and second exciting electrodes and the first and second exciting electrodes of the piezoelectric vibrating plate, respectively. The first and second sealing members to be joined to the two main surfaces thereof are provided, and at least one of the first and second sealing members is a resin film, and the piezoelectric vibrating plate is It has a vibrating portion in which the first and second excitation electrodes are formed on both main surfaces thereof, and an outer frame portion surrounding the vibrating portion. The vibrating portion is thinner than the outer frame portion. The resin film has its peripheral end bonded to at least one main surface of both main surfaces of the outer frame portion, and the resin film covering the first excitation electrode or the second excitation electrode is The covering region of the resin film is bent so as to be close to the first excitation electrode or the second excitation electrode, and the main surface of the outer frame portion to which the resin film is bonded is formed on the first surface. The distance between the virtual extension surface extended to the position facing the first excitation electrode or the second excitation electrode and the first excitation electrode or the second excitation electrode is a distance exceeding the amount of deflection of the resin film.

According to the piezoelectric vibration device according to the present invention, the first and second encapsulations are made so as to cover the first and second excitation electrodes of the piezoelectric diaphragm in which the first and second excitation electrodes are formed on both main surfaces. Since the members are joined and sealed, it is not necessary to store and mount the piezoelectric vibrating piece in a box-shaped base having an open upper surface and seal it, and an expensive base is not required.

Further, since at least one of the sealing members of the first and second sealing members is made of a resin film, as compared with the case where both sealing members are made of a metal or ceramic lid. The cost can be reduced.

Further, in the resin film covering the first excitation electrode or the second excitation electrode of the piezoelectric vibrating plate, the region covering the first excitation electrode or the second excitation electrode is formed by heat crimping to the piezoelectric vibrating plate or the like. The position where the main surface of the outer frame of the piezoelectric vibrating plate to which the resin film is bonded is opposed to the first excitation electrode or the second excitation electrode, although it is bent so as to be close to the first excitation electrode or the second excitation electrode. Since the distance between the virtual extension surface extended to the above and the first excitation electrode or the second excitation electrode exceeds the amount of deflection of the resin film, the resin film comes into contact with the first excitation electrode or the second excitation electrode. Can be prevented.

(2) In a preferred embodiment of the present invention, the piezoelectric diaphragm is a substantially rectangular shape in a plan view, and one of the two sets of opposite sides in the substantially rectangular shape in a plan view in a direction along the opposite side of one set. The first metal film is formed on the outer frame portion at the end portion, and the second metal film is formed on the outer frame portion at the other end portion.

According to this embodiment, since the first and second metal films are formed at both ends in the direction along the opposite sides of one set of substantially rectangular plane views, both ends in the direction along the opposite sides are formed. The 1st and 2nd metal films can be used as the 1st and 2nd mounting terminals, and the 1st and 2nd mounting terminals can be used on a circuit board or the like by using a bonding material such as solder, a metal bump or a wire. The piezoelectric vibrating device can be mounted by joining.

(3) In one embodiment of the present invention, the distance between the virtual extension surface and the first excitation electrode or the second excitation electrode is at least twice the bending amount of the resin film.

According to this embodiment, the distance between the virtual extension surface and the first excitation electrode or the second excitation electrode is at least twice the deflection amount of the resin film, so that the deflection amount of the resin film varies. Also, it is possible to prevent contact with the first excitation electrode or the second excitation electrode.

(4) In another embodiment of the present invention, the piezoelectric diaphragm is a quartz diaphragm.

According to this embodiment, vibration in which the main surface of the outer frame portion of the quartz diaphragm to which the resin film is bonded and the first excitation electrode or the second excitation electrode are formed by etching the quartz plate constituting the quartz diaphragm. The distance from the main surface of the portion can be formed to a required distance in consideration of the amount of bending of the resin film.

According to the present invention, the first and second sealing members are joined and sealed so as to cover the first and second excitation electrodes formed on both main surfaces of the piezoelectric diaphragm, as in the conventional case. There is no need to store and mount the piezoelectric vibrating piece in a box-shaped base with an open top surface and seal it, eliminating the need for an expensive base.

Further, since at least one of the sealing members of the first and second sealing members is made of a resin film, as compared with the case where both sealing members are made of a metal or ceramic lid. The cost can be reduced.

Further, a virtual extension surface obtained by extending the main surface of the outer frame portion of the piezoelectric vibrating plate to which the resin film is bonded to a position facing the first excitation electrode or the second excitation electrode, and the first excitation electrode or the second excitation electrode. Since the distance from the electrode exceeds the amount of deflection of the resin film, it is possible to prevent the resin film from coming into contact with the first excitation electrode or the second excitation electrode.

FIG. 1 is a schematic perspective view of a crystal oscillator according to an embodiment of the present invention. FIG. 2 is a schematic plan view of a quartz diaphragm constituting the crystal oscillator of FIG. 1. FIG. 3 is a schematic cross-sectional view taken along the line AA of the crystal diaphragm of FIG. FIG. 4 is a schematic cross-sectional view taken along the line BB of the crystal diaphragm of FIG. FIG. 5 is a schematic bottom view of the crystal diaphragm constituting the crystal oscillator of FIG. 1. FIG. 6 is a schematic cross-sectional view corresponding to FIG. 3 of the crystal oscillator of FIG. FIG. 7 is a schematic cross-sectional view corresponding to FIG. 4 of the crystal oscillator of FIG. FIG. 8 is an enlarged view of section P1 of FIG. FIG. 9 is a schematic cross-sectional view schematically showing the manufacturing process of the crystal oscillator of FIG. FIG. 10 is a schematic cross-sectional view schematically showing the heat-bonding process of the resin film of FIG. 9 (d). FIG. 11 is a schematic plan view of a quartz diaphragm constituting the crystal oscillator according to another embodiment of the present invention. FIG. 12 is a schematic bottom view of the crystal diaphragm of FIG. FIG. 13 is a schematic perspective view corresponding to FIG. 1 of still another embodiment of the present invention. FIG. 14 is a schematic cross-sectional view corresponding to FIG. 6 of the embodiment of FIG.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In this embodiment, it will be described by applying it to a crystal oscillator as a crystal vibration device.

FIG. 1 is a schematic perspective view of a crystal oscillator according to an embodiment of the present invention.

The crystal oscillator 1 of this embodiment has an AT-cut crystal diaphragm 2 on which a metal film is formed and the first and second metals at both ends on both the front and back surfaces of the AT-cut crystal diaphragm 2. The first and second resin films 3 and 4 bonded so as to cover the rectangular regions excluding the films 27 and 28, respectively (in FIG. 1, only the first resin film 3 bonded to one main surface is shown. It has) and.

The crystal oscillator 1 has a rectangular parallelepiped shape and is a rectangular parallelepiped. The crystal oscillator 1 of this embodiment has, for example, 1.2 mm × 1.0 mm and a thickness of 0.2 mm in a plan view, and is aimed at miniaturization and low profile.

The size of the crystal oscillator 1 is not limited to the above, and a size different from the above can be applied.

FIG. 2 is a schematic plan view of the crystal diaphragm 2 constituting the crystal oscillator 1 of FIG. 1, that is, the crystal oscillator 1 in a state where the first and second resin films 3 and 4 are not bonded. 3 is a schematic cross-sectional view of the crystal diaphragm 2 of FIG. 2 along the line AA, FIG. 4 is a schematic cross-sectional view of the crystal diaphragm 2 of FIG. 2 along the line BB, and FIG. 5 is a schematic cross-sectional view. , It is a schematic bottom view of the crystal diaphragm 2. In FIGS. 3 and 4 and FIGS. 9 and 10 described later, the metal film formed on the quartz diaphragm 2 is exaggerated for convenience of explanation.

The quartz diaphragm 2 of this embodiment is an AT-cut quartz plate processed by rotating a rectangular quartz plate around the X-axis, which is the crystal axis of quartz, by 35 ° 15', and the new rotated axis is Y. It is called the'and Z'axis. In the AT-cut quartz plate, both front and back main surfaces are XZ'planes.

In this XZ'plane, the short side direction of the rectangular crystal diaphragm 2 in plan view (vertical direction in FIGS. 2 and 5) is the X-axis direction, and the long side direction of the crystal diaphragm 2 (left and right in FIGS. 2 and 5). Direction) is the Z'axis direction.

The crystal diaphragm 2 connects a vibrating portion 21 having a substantially rectangular plan view, an outer frame portion 23 that surrounds the vibrating portion 21 with a penetrating portion 22 interposed therebetween, and the vibrating portion 21 and the outer frame portion 23. It is provided with a connecting portion 24 to be formed. The vibrating portion 21, the outer frame portion 23, and the connecting portion 24 are integrally formed. The vibrating portion 21 and the connecting portion 24 are formed thinner than the outer frame portion 23. That is, the vibrating portion 21 including the connecting portion 24 is thinner than the outer frame portion 23.

A pair of first and second excitation electrodes 25 and 26 are formed on both main surfaces of the front and back surfaces of the vibrating portion 21, respectively.

On one of the main surfaces of both main surfaces, as shown in FIG. 2, the first and second resin films 3 and 4 are formed on the outer frame portions 23 at both ends of the rectangular crystal diaphragm 2 in a plan view in the long side direction. The first and second metal films 27 and 28, which are not covered with, are formed along the short side direction of the crystal diaphragm 2, respectively. That is, the first and second metal films 27 and 28 are formed at both ends of the crystal diaphragm 2 in the long side direction (Z'axis direction) with the vibrating portion 21 interposed therebetween. A first sealing pattern 201 formed in a rectangular annular shape so as to surround the vibrating portion 21 is continuously provided on the first metal film 27 formed over both main surfaces.

On the other main surface of both main surfaces, as shown in FIG. 5, the first and second metal films 27 and 28 are formed on the outer frame portions 23 at both ends of the rectangular crystal diaphragm 2 in a plan view in the long side direction. Are formed along the short side direction of the crystal diaphragm 2. A second sealing pattern 202 formed in a rectangular annular shape so as to surround the vibrating portion 21 is continuously provided on the second metal film 28 formed over both main surfaces.

The first metal film 27 is formed in a region not covered by the rectangular first resin film 3 shown in FIG. 1, and is exposed to the outside. Similarly, the second metal film 28 is formed in a region not covered by the second resin film 4, which will be described later, and is exposed to the outside. These metal films 27 and 28 are used as mounting terminals for mounting the crystal oscillator 1 on a circuit board or the like.

The first metal films 27 on both main surfaces of the crystal diaphragm 2 and the second metal films 28 are electrically connected to each other. In this embodiment, the first metal films 27 and the second metal films 28 on both main surfaces are electrically connected to each other by a routing electrode routed around the opposite long side side surfaces of the crystal diaphragm 2. At the same time, the side surfaces of the crystal diaphragm 2 on the opposite short side are electrically connected by a routed electrode.

Since the first metal films 27 and the second metal films 28 on both main surfaces are electrically connected to each other in this way, the crystal oscillator 1 is connected to the first and second metal films 27 and 28. When mounting as a mounting terminal on a circuit board or the like, it can be mounted on either the front or back main surface.

The first metal films 27 and the second metal films 28 on both main surfaces may be electrically connected to each other via a through electrode penetrating both main surfaces, or a side routing electrode may be used. It may be electrically connected via a through electrode and may be electrically connected via a through electrode.

As shown in FIG. 2, the rectangular annular first sealing pattern 201 on one main surface side of the crystal diaphragm 2 is located at one end of the crystal diaphragm 2 in the long side direction (Z'axis direction). A connecting portion 201a connected to the first metal film 27, first extending portions 201b and 201b extending from both ends of the connecting portion 201a along the long side direction (Z'axis direction), and a crystal diaphragm. It is provided with a second extending portion 201c that extends along the short side direction (X-axis direction) of 2 and connects the extending ends of the first extending portions 201b and 201b. The second extension portion 201c is connected to the first extraction electrode 203 drawn from the first excitation electrode 25. Therefore, the first metal film 27 is electrically connected to the first excitation electrode 25 via the first drawer electrode 203 and the first sealing pattern 201. An electrodeless region in which no electrode is formed is provided between the second extending portion 201c extending along the short side direction of the quartz diaphragm 2 and the second metal film 28, and the first sealing is performed. The pattern 201 and the second metal film 28 are insulated from each other.

As shown in FIG. 5, the rectangular annular second sealing pattern 202 on the other main surface side of the crystal diaphragm 2 is located at the other end of the crystal diaphragm 2 in the long side direction (Z'axis direction). The connecting portion 202a connected to the second metal film 28, the first extending portions 202b and 202b extending from both ends of the connecting portion 202a along the long side direction, and the short side direction of the crystal diaphragm 2. It extends along the line and includes a second extension portion 202c that connects the extension ends of the first extension portions 202b and 202b. The connection portion 202a is connected to the second extraction electrode 204 drawn from the second excitation electrode 26. Therefore, the second metal film 28 is electrically connected to the second excitation electrode 26 via the connection portion 202a of the second extraction electrode 204 and the second sealing pattern 202. An electrodeless region in which no electrode is formed is provided between the second extending portion 202c extending along the short side direction of the quartz diaphragm 2 and the first metal film 27, and the second sealing is provided. The pattern 202 and the first metal film 27 are insulated from each other.

As shown in FIG. 2, the widths of the first extending portions 201b and 201b of the first sealing pattern 201 extending along the long side direction of the crystal diaphragm 2 are along the long side direction. Electrodeless regions are provided on both sides of the first extending portions 201b, 201b in the width direction (vertical direction in FIG. 2), which is narrower than the width of the extending outer frame portion 23, and in which electrodes are not formed.

Of the electrodeless regions on both sides of the first extending portions 201b and 201b, the outer non-electrode regions extend to the first metal film 27, and the second metal film 28 and the second extending portion 201c It is connected to the electrodeless area between them. As a result, the outside of the connection portion 201a, the first extension portion 201b, 201b, and the second extension portion 201c of the first sealing pattern 201 is surrounded by electrodeless regions having substantially the same width. This electrodeless region extends from the outside of one end of the connecting portion 201a extending along the short side direction of the crystal diaphragm 2 along the first extending portion 201b, and extends from the extending end to the second extending portion. It extends along 201c and extends from the extending end to the outside of the other end of the connecting portion 201a along the other first extending portion 201b.

An electrodeless region is formed inside the connection portion 201a of the first sealing pattern 201 in the width direction, and this electrodeless region is continuous with the electrodeless region inside the first extension portions 201b, 201b. There is. An electrodeless region is formed inside the second extending portion 201c in the width direction except for the first drawing electrode 203 of the connecting portion 24, and this electrodeless region is formed in the first extending portions 201b and 201b. It is connected to the inner electrodeless region. As a result, the inside of the connecting portion 201a, the first extending portion 201b, 201b, and the second extending portion 201c of the first sealing pattern 201 in the width direction except for the first drawing electrode 203 of the connecting portion 24. It is surrounded by a rectangular annular electrodeless region in plan view.

As shown in FIG. 5, the widths of the first extending portions 202b and 202b of the second sealing pattern 202 extending along the long side direction of the crystal diaphragm 2 are along the long side direction. Electrodeless regions are provided on both sides of the first extending portions 202b, 202b in the width direction (vertical direction in FIG. 5), which are narrower than the width of the extending outer frame portion 23 and have no electrodes formed.

Of the electrodeless regions on both sides of the first extending portions 202b and 202b, the outer non-electrode regions extend to the second metal film 28, and the first metal film 27 and the second extending portion 202c It is connected to the electrodeless area between them. As a result, the outside of the connection portion 202a, the first extension portion 202b, 202b, and the second extension portion 202c of the second sealing pattern 202 is surrounded by electrodeless regions having substantially the same width. This electrodeless region extends from the outside of one end of the connecting portion 202a extending along the short side direction of the crystal diaphragm 2 along one of the first extending portions 202b, and extends from the extending end to the second extending portion. It extends along 202c and extends from the extending end to the outside of the other end of the connecting portion 201a along the other first extending portion 202b.

An electrodeless region is formed inside the connecting portion 202a of the second sealing pattern 202 in the width direction except for the second drawer electrode 204 of the connecting portion 24, and this electrodeless region is the first extending portion. It is connected to the electrodeless region inside 202b and 202b. An electrodeless region is formed inside the second extending portion 202c in the width direction, and this electrodeless region is continuous with the inner non-electrode region of the first extending portions 202b, 202b. As a result, the inside of the connecting portion 202a, the first extending portion 202b, 202b, and the second extending portion 202c of the second sealing pattern 202 in the width direction except for the second drawing electrode 204 of the connecting portion 24. It is surrounded by a rectangular annular electrodeless region in plan view.

As described above, the first extension portions 201b, 201b; 202b, 202b of the first and second sealing patterns 201, 202 are made narrower than the width of the outer frame portion 23, and the first extension portions 201b, 201b; Electrodeless regions are provided on both sides of 202b and 202b in the width direction, and electrodeless regions are provided inside the connecting portions 201a and 202a and the second extending portions 201c and 202c in the width direction. The electrodeless region is formed by patterning the first and second sealing patterns 201 and 202 that wrap around the side surface of the outer frame portion 23 during sputtering by photolithography technology and removing them by metal etching. .. As a result, it is possible to prevent a short circuit caused by the first and second sealing patterns 201 and 202 wrapping around the side surface of the outer frame portion 23.

The first and second excitation electrodes 25 and 26 of the crystal diaphragm 2, the first and second metal films 27 and 28, the first and second sealing patterns 201 and 202, and the first and second extraction electrodes 203, In 204, for example, Au is laminated on a base layer made of, for example, Ti or Cr, and further, for example, Ti, Cr or Ni is laminated and formed.

In this embodiment, the base layer is Ti, and Au and Ti are laminated and formed on the base layer. Since the uppermost layer is Ti in this way, the bonding strength with the polyimide resin film described later is improved as compared with the case where Au is the uppermost layer.

As described above, the upper layer of the rectangular annular first and second sealing patterns 201 and 202 to which the rectangular first and second resin films 3 and 4 are bonded is made of Ti, Cr or Ni (or oxides thereof). ), So that the bonding strength with the first and second resin films 3 and 4 can be increased as compared with Au and the like.

In this embodiment, as the first and second sealing members, the first and second excitation electrodes 25 and 26 of the quartz diaphragm 2 are covered on both main surfaces of the quartz diaphragm 2 having the above configuration. 1, The second resin films 3 and 4 are bonded.

6 and 7 are schematic cross-sectional views of the crystal oscillator 1 of FIG. 1, and FIG. 2 shows a state in which the first and second resin films 3 and 4 are bonded to the crystal diaphragm 2 of FIG. It is a schematic cross-sectional view along the line AA and the line BB. FIG. 8 is an enlarged view of section P1 of FIG. The excitation electrodes 25, 26, the metal films 27, 28, etc. are negligibly thinner than the crystal diaphragm 2 and the first and second resin films 3, 4, and are omitted in FIGS. 6 and 7. ing. Further, the bending of the first and second resin films 3 and 4 is exaggerated.

The first and second resin films 3 and 4 are rectangular films. The rectangular first and second resin films 3 and 4 have the first and second sealing patterns 201, except for the first and second metal films 27 and 28 at both ends in the longitudinal direction of the crystal diaphragm 2. It is a size that covers a rectangular area including 202, and is joined to the rectangular area.

In this embodiment, the first and second resin films 3 and 4 are heat-resistant resin films, for example, polyimide resin films.

The first and second resin films 3 and 4 have a thermoplastic adhesive layer formed on the entire front and back surfaces. The first and second resin films 3 and 4 are, for example, heat-pressed so that their rectangular peripheral ends seal the vibrating portions 21 on the outer frame portions 23 on both main surfaces of the quartz diaphragm 2. Each is heat-bonded.

As shown in FIGS. 6 and 7, the first and second resin films 3 and 4 to be heat-bonded in this way cover the vibrating portion 21 in which the first and second excitation electrodes 25 and 26 are formed. The region is bent so as to be close to the first and second excitation electrodes 25 and 26 of the vibrating portion 21.

In this embodiment, the first and second resin films 3 and 4 bent so as to be close to the first and second excitation electrodes 25 and 26 of the vibrating portion 21 are the first and first vibrating portions 21 of the vibrating portion 21. 2 It is configured as follows so as not to come into contact with the excitation electrodes 25 and 26.

First, the position where one main surface F1 of the outer frame portion 23 of the vibrating portion 21 to which the first and second resin films 3 and 4, for example, the first resin film 3 are bonded is opposed to the first excitation electrode 25. It is assumed that the virtual extension surface VF1 shown in FIGS. 6 and 8 is extended to. In this embodiment, as shown in FIG. 8, the distance between the virtual extension surface VF1 and the first excitation electrode 25, that is, the vertical distance D1, is a distance that exceeds the bending amount D2 of the first resin film 3.

Since the peripheral end of the first resin film 3 is bonded to one main surface F1 of the outer frame portion 23 around the vibrating portion 21, the first excitation electrode 25 side is in the central portion of the first resin film 3. The most flexible amount D2 is the virtual extension surface VF1 in which one main surface F1 of the outer frame portion 23 to which the first resin film 3 is bonded is extended to a position facing the first excitation electrode 25. , The vertical distance to the most bent portion of the first resin film 3.

In this way, the vertical distance D1 between the virtual extension surface VF1 in which one main surface F1 of the outer frame portion 23 of the vibrating portion 21 is extended to a position facing the first excitation electrode 25 and the first excitation electrode 25 is formed. Since the distance exceeds the deflection amount D2 of the first resin film 3, the first resin film 3 that is bent so as to be close to the first excitation electrode 25 does not come into contact with the first excitation electrode 25 of the vibrating portion 21. Can be prevented.

Although the first resin film 3 has been described with reference to FIG. 8, the vibrating portion 21 on which the first and second excitation electrodes 25 and 26 are formed is in the thickness direction of the outer frame portion 23 (vertical direction in FIG. 6). Since it is located in the center of the left-right direction in FIG. 7, the other main surface F2 of the outer frame portion 23 of the vibrating portion 21 to which the second resin film 4 is bonded faces the second excitation electrode 26. The vertical distance between the virtual extension surface VF2 extended to the above and the second excitation electrode 26 is D1. Further, since the second resin film 4 is also heat-bonded to the outer frame portion 23 in the same manner as the first resin film 3, the amount of deflection of the second resin film 4 toward the second excitation electrode 26 is also D2.

In this embodiment, the bending amount D2 of the first and second resin films 3 and 4 is, for example, about 10 μm, whereas the main surface of the outer frame portion 23 of the vibrating portion 21 is the first excitation electrode. The vertical distance D1 between the virtual extension surfaces VF1 and VF2 extended to the position facing the 25 and the first excitation electrode 25 or the second excitation electrode 26 is twice or more the deflection amount D2, for example, about 20 μm.

Since the first and second resin films 3 and 4 of this embodiment are polyimide resin films having a heat resistance of about 300 ° C., a solder reflow process when the crystal transducer 1 is solder-mounted on a circuit board or the like. It can withstand the high temperature of the above, and the first and second resin films 3 and 4 are not deformed or the like.

Although the polyimide resin films 3 and 4 are transparent, they may become opaque depending on the conditions of heat crimping described later. The first and second resin films 3 and 4 may be transparent, opaque, or translucent.

The first and second resin films 3 and 4 are not limited to polyimide resins, and resins classified as super engineering plastics, such as polyamide resins and polyether ether ketone resins, may be used.

In this embodiment, as shown in FIG. 2, since the vibrating portion 21 having a substantially rectangular plan view is connected to the outer frame portion 23 by a connecting portion 24 provided at one corner of the vibrating portion 21, 2 The stress acting on the vibrating portion 21 can be reduced as compared with the configuration in which the portions are connected at or above.

Further, in this embodiment, the connecting portion 24 protrudes from one side of the inner circumference of the outer frame portion 23 along the X-axis direction and is formed along the Z'axis direction. The first and second metal films 27 and 28 formed at both ends of the crystal diaphragm 2 in the Z'axis direction are used as mounting terminals and are directly bonded to a circuit board or the like by soldering or the like. Therefore, it is conceivable that the contraction stress acts in the long side direction (Z'axis direction) of the crystal oscillator, and the stress propagates to the vibrating portion, so that the oscillation frequency of the crystal oscillator is likely to change. On the other hand, in this embodiment, since the connecting portion 24 is formed in the direction along the contraction stress, it is possible to suppress the contraction stress from propagating to the vibrating portion 21. As a result, it is possible to suppress a change in the oscillation frequency when the crystal oscillator 1 is mounted on the circuit board.

The penetrating portion 22 between the vibrating portion 21 and the outer frame portion 23 may be omitted, and the outer frame portion 23 may be continuously provided in the vibrating portion 21 so as to surround the thin-walled vibrating portion 21.

Next, a method for manufacturing the crystal oscillator 1 of this embodiment will be described.

FIG. 9 is a schematic cross-sectional view schematically showing a process of manufacturing the crystal oscillator 1.

First, the AT-cut crystal wafer (AT-cut crystal plate) 5 before processing shown in FIG. 9A is prepared. As shown in FIG. 9B, the outer shape of a plurality of crystal diaphragm portions 2a and a frame portion (not shown) supporting them is obtained by wet etching the crystal wafer 5 using a photolithography technique. Further, the outer shape of each part such as the outer frame portion 23a and the vibrating portion 21a thinner than the outer frame portion 23a is formed on the crystal diaphragm portion 2a. That is, the processing process of the outer shape and the vibrating portion is carried out. In the process of processing the outer shape and the vibrating portion, the thickness of the vibrating portion 21a with respect to the outer frame portion 23a is etched so as to be a required thickness in consideration of the amount of bending of the first and second resin films 3 and 4.

Next, as shown in FIG. 9 (c), the first and second excitation electrodes 25a, 26a and the first are used at predetermined positions of the crystal vibrating plate portion 2a by the sputtering technique or the vapor deposition technique and the photolithography technique. , The electrode forming step of forming the second metal films 27a, 28a and the like is carried out.

Further, as shown in FIG. 9D, the resin films 3a and 4a are heat-bonded so as to cover the entire surfaces of both the front and back surfaces of each crystal diaphragm portion 2a with the continuous resin films 3a and 4a, respectively. Then, each vibrating portion 21a of each crystal diaphragm portion 2a is sealed.

FIG. 10 is a schematic cross-sectional view schematically showing a step of heat-pressing the resin films 3a and 4a to each quartz diaphragm portion 2a.

First, as shown in FIG. 10 (a), between the upper pressure heating block 7 and the lower pressure heating block 8, both main surfaces are covered with resin films 3a and 4a, respectively. The diaphragm portion 2a is set with the protective film 6 interposed above and below it.

Next, as shown in FIG. 10B, the first and second resin films 3a and 4a are pressure-heated and pressure-bonded to the respective crystal diaphragm portions 2a by the upper and lower pressure-heating blocks 7 and 8. ..

Next, as shown in FIG. 10 (c), each crystal diaphragm portion 2a to which the first and second resin films 3a and 4a are bonded is taken out. Then, the protective film 6 is removed in the protective film removing step.

The step of heat-pressing the resin films 3a and 4a to each quartz diaphragm portion 2a is performed in an atmosphere of an inert gas such as nitrogen gas. The step of heat crimping is not limited to the atmosphere of the inert gas, but may be performed in the atmosphere of the atmosphere or the atmosphere of reduced pressure.

Next, as shown in FIG. 9 (e), the continuous resin films 3a and 4a are exposed so that the first and second metal films 27 and 28 are exposed so as to correspond to the respective crystal diaphragms 2. It is cut to remove unnecessary parts, and each crystal diaphragm 2 is separated and separated into individual pieces.

As a result, a plurality of crystal oscillators 1 shown in FIG. 1 are obtained.

According to the present embodiment, the main surfaces F1 and F2 of the outer frame portion 23 of the vibrating portion 21 to which the first and second resin films 3 and 4 are bonded are attached to the first and second excitation electrodes 25 and 26. Since the vertical distance D1 between the virtual extension surfaces VF1 and VF2 extended to the opposite positions and the first and second excitation electrodes 25 and 26 exceeds the deflection amount D2 of the first and second resin films 3 and 4. The first and second resin films 3 and 4, which are bent so as to be close to the first and second excitation electrodes 25 and 26, come into contact with the first and second excitation electrodes 25 and 26 of the vibrating portion 21. Can be prevented.

Further, according to the present embodiment, since the crystal oscillator 1 is formed by joining the first and second resin films 3 and 4 to both the front and back main surfaces of the quartz diaphragm 2, the quartz oscillator 1 is made of an insulating material such as ceramic. The expensive base and lid are not required as in the conventional example in which the crystal vibrating piece is housed in the base having the concave portion, the lid is joined to the base, and the quartz vibrating piece is hermetically sealed.

As a result, the cost of the crystal oscillator 1 can be reduced, and the crystal oscillator 1 can be provided at low cost.

In addition, it is possible to reduce the thickness (lower height) as compared with the conventional example in which the quartz vibrating piece is stored in the concave portion of the base and sealed with the lid.

In the crystal oscillator 1 of the present embodiment, since the vibrating portion 21 is sealed by the first and second resin films 3 and 4, a metal or ceramic lid is joined to the base and hermetically sealed. The airtightness is inferior to that of the conventional example, and the resonance frequency of the crystal oscillator 1 tends to change over time.

However, for example, in short-range wireless communication applications such as BLE (Bluetooth (registered trademark) Low Energy), standards such as frequency deviation are relatively loose, so in such applications, inexpensive crystals sealed with a resin film are used. It is possible to use the oscillator 1.

In the above embodiment, as shown in FIG. 2, the first sealing pattern 201 to which the first resin film 3 is bonded is formed on one main surface of both main surfaces of the crystal diaphragm 2, and the vibrating portion is substantially rectangular. As shown in FIG. 5, a second sealing pattern 202, which is formed in a rectangular annular shape so as to surround 21 and to which the second resin film 4 is bonded, is formed on the other main surface of both main surfaces of the crystal diaphragm 2. Although it is formed in a rectangular annular shape so as to surround the substantially rectangular vibrating portion 21, the first and second sealing patterns 201 and 202 of the rectangular annular shape may be omitted.

11 and 12 are a schematic plan view and a schematic bottom view of the crystal diaphragm 21 excluding the _first and second sealing patterns 201 and 202.

In the quartz diaphragm 21, as shown in FIG. 11, the _first metal film 27 is electrically connected to the first excitation electrode 25 via the routing electrode 209 and the first extraction electrode 203.

As shown in FIG. 12, the second metal film 28 is electrically connected to the second excitation electrode 26 by extending the second extraction electrode 204.

Other configurations are the same as those in the above embodiment.

In each of the above embodiments, the first and second metal films 27 and 28 of the crystal diaphragms 2 and 2 ₁ function as mounting terminals for mounting the crystal oscillator 1 on a circuit board or the like as described above. have. As another embodiment of the present invention, the first and second mounting terminals are formed separately from the first and second metal films 27 and 28, and the first and second metal films 27 and 28 are formed by the first and first metal films 27 and 28. The two mounting terminals may function as connection electrodes for electrically connecting the first and second excitation electrodes 25 and 26.

The embodiment in which the first and second metal films 27 and 28 function as connection electrodes for electrically connecting the first and second mounting terminals and the first and second excitation electrodes 25 and 26 is shown in the figure. 13 and FIG. 14 are shown.

13 and 14 are _a schematic perspective view and a schematic cross-sectional view of the crystal oscillator 11. The external size of the crystal oscillator ₁ of this embodiment is the same as the external size of the crystal oscillator 1 of each of the above embodiments.

The crystal vibrating plate 2 ₂ of the crystal oscillator 1 ₁ of this embodiment has a vibrating portion 21 ₁ on which the first and second excitation electrodes 25 ₁ , 26 ₁ are formed and the vibrating portion 21 2 thereof, as in each of the above embodiments. It is provided with an outer frame portion 23 ₁ that surrounds the periphery of the 21 ₁ with the penetrating portion 22 ₁ interposed therebetween, and a connecting portion 24 ₁ that connects the vibrating portion 21 ₁ and the outer frame portion 23 ₁ .

In this embodiment, the first and second resin films 3 ₁ and 4 ₁ are the vibrating portion 21 1 on which the first and second exciting electrodes 25 ₁ and 26 ₁ of the quartz diaphragm 2 ₂ are formed and the rectangular shape around the vibrating portion 21 ₁ and the surroundings thereof. It is joined so as to cover not only the region of the above but also the entire surfaces of _both main surfaces of the crystal diaphragm 22. That is, the sizes of the first and second resin films 3 ₁ and 4 ₁ are larger than the sizes of the first and second resin films 3 and 4 of each of the above embodiments, and are the same size as the crystal diaphragm 2 ₂ . ..

Therefore, as shown in FIG. 14, of the first and _second metal films 27 ₁ , 28 ₁ formed on the quartz diaphragm 22, the portions formed on both main surfaces are the first and second metal films. It is covered with resin films 3 ₁ and 4 ₁ .

In this embodiment, the first and second resin films 3 are attached to both ends of the quartz diaphragm 2 ₂ in which the first and second resin films 3 ₁ and 4 ₁ are bonded to the entire surfaces of both main surfaces in the long side direction. A conductive paste is applied so as to cover substantially the entire outer surface of ₁ , ₄₁ and the crystal diaphragm 22 and heat-cured to form the first and _second mounting terminals 17 and 18.

Similar to each of the above-described embodiments, the first metal film 27 ₁ is formed on each side surface on the long side facing each other and the short side facing each other on one end of _both ends in the long side direction of the quartz diaphragm 22. It is formed over one side. Since the first mounting terminal 17 is formed on the first metal film 27 ₁ , the first mounting terminal 17 is electrically connected to the first metal film 27 ₁ . Since the first metal film 27 ₁ is electrically connected to the first excitation electrode 25 ₁ as in each of the above embodiments, the first metal film 27 ₁ is the first excitation electrode 25 ₁ and the first. It functions as a connection electrode for electrically connecting to the mounting terminal 17.

Similarly, the second metal film 28 ₁ extends over each side surface on the opposite long side and the other side surface on the opposite short side of the other end of _both ends in the long side direction of the quartz diaphragm 22. Is formed. Since the second mounting terminal 18 is formed on the _second metal film 281, the _second mounting terminal 18 is electrically connected to the second metal film 281. Since the second metal film 28 ₁ is electrically connected to the second excitation electrode 26 ₁ , the second metal film 28 ₁ electrically connects the second excitation electrode 26 ₁ and the second mounting terminal 18. Functions as a connecting electrode to connect.

In this embodiment, the first and second mounting terminals 17 and 18 are formed on the outer surface of the first and _second resin films 3 ₁ and 4 ₁ bonded to the crystal diaphragm 22. As shown in FIGS. 6 and 14, as compared with the configuration in which the first and second metal films 27 and 28 formed on the crystal diaphragms ₂ and 21 are used as the first and second mounting terminals as described above. , The size of the first and _second metal films 27 ₁ , 28 ₁ formed on the crystal diaphragm 22 can be reduced, and the vibration sandwiched between the first and second metal films 27 ₁ , 28 ₁ can be reduced accordingly. _The size of the portion 211 can be increased.

As a result, the vibrating portion 21 ₁ can be lengthened along the long side direction of the crystal diaphragm 2 ₂ to improve the vibration characteristics without increasing the size of the crystal oscillator 1 ₁ itself, and the crystal can be improved. It is possible to secure the junction regions of the _first and second mounting terminals 17 and 18 required for mounting the oscillator 11.

In each of the above embodiments, the connecting portions 24 and 24 ₁ are provided at _one corner of the vibrating portions 21 and 21 ₁ having a substantially rectangular plan view. The number of formations is not limited to this. Further, the widths of the connecting portions 24 and ₂₄₁ do not have to be constant.

Further, it may be applied to an inverted mesa type quartz diaphragm having a thin vibrating portion and a thick peripheral portion without having a penetrating portion.

In each of the above embodiments, the first and second resin films 3, 3 ₁ ; 4, 4 ₁ having a thermoplastic adhesive layer are heat-bonded to the crystal vibrating plates ₂ , 2 ₁ , 22. As another embodiment, a photosensitive resin film, for example, a photosensitive polyimide film is used as the first and second resin films, and the photosensitive resin film is laminated on a crystal vibrating plate and exposed via a photomask. , It may be developed to remove unnecessary portions of the photosensitive resin film and to be cured.

In each of the above embodiments, the first and second resin films 3, 4; 3 ₁ , 4 ₁ are bonded to both main surfaces of the crystal diaphragms 2, 2 ₁ and 2 ₂ to seal the vibrating portion 21. However, instead of the resin film on at least one main surface, a conventional lid may be joined to seal the vibrating portion 21.

The crystal diaphragm may be a substantially rectangular shape in a plan view, and is not limited to the rectangle in a plan view as described above. It may have a shape in which a notch, a rectangle or the like in which an electrode is adhered to the notch, is formed.

The present invention is not limited to the crystal oscillator, and may be applied to other crystal vibration devices such as a crystal oscillator.

1,1 ₁ Crystal oscillator 2,2 1,2 ₂ Crystal vibrating plate 3,3 _{1 First resin film 4,4 1 Second} resin film 5 Crystal wafer 21,21 ₁ Vibrating part 23,23 ₁ Outer frame part 24 , 24 ₁ Connection part 25, 25 ₁ 1st excitation electrode 26,26 ₁ 2nd excitation electrode 27,27 ₁ 1st metal film 28,28 ₁ 2nd metal film 201 1st sealing pattern 202 2nd sealing pattern

Claims (4)

It has a first excitation electrode formed on one main surface of both main surfaces and a second excitation electrode formed on the other main surface of both main surfaces, and is connected to the first and second excitation electrodes, respectively. A piezoelectric diaphragm having first and second metal films,
A first and second sealing member to be joined to both main surfaces of the piezoelectric diaphragm so as to cover the first and second excitation electrodes of the piezoelectric diaphragm is provided.
At least one of the first and second sealing members is a resin film.
The piezoelectric diaphragm has a vibrating portion in which the first and second excitation electrodes are formed on both main surfaces thereof, and an outer frame portion surrounding the vibrating portion, and the vibrating portion is the outer frame portion. Thinner and
The peripheral end of the resin film is joined to at least one main surface of both main surfaces of the outer frame portion.
In the resin film covering the first excitation electrode or the second excitation electrode, the covering region of the resin film is bent so as to be close to the first excitation electrode or the second excitation electrode. ,
A virtual extension surface obtained by extending the main surface of the outer frame portion to which the resin film is bonded to a position facing the first excitation electrode or the second excitation electrode, and the first excitation electrode or the second excitation electrode. The distance from the electrode is a distance that exceeds the amount of deflection of the resin film.
A piezoelectric vibration device characterized by that. The piezoelectric diaphragm has a substantially rectangular shape in a plan view, and the outer frame portion of the outer frame portion at one end in a direction along the facing side of one of the two sets of facing sides in the substantially rectangular shape in a plan view. One metal film is formed, and the second metal film is formed on the outer frame portion at the other end.
The piezoelectric vibration device according to claim 1. The distance between the virtual extension surface and the first excitation electrode or the second excitation electrode is at least twice the bending amount of the resin film.
The piezoelectric vibration device according to claim 1 or 2. The piezoelectric diaphragm is a quartz diaphragm.
The piezoelectric vibration device according to any one of claims 1 to 3.

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