JP2022034229A - Manufacturing method of piezoelectric vibration device and piezoelectric vibration device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive piezoelectric vibration device and a method for manufacturing the same.
SOLUTION: A piezoelectric wafer in which a plurality of piezoelectric vibrating plates having first and second excitation electrodes formed on both main surfaces are supported in an arrangement is prepared, and at least one of the main surfaces of both main surfaces of the piezoelectric wafer is prepared. A photosensitive resin film is attached to the surface, and the photosensitive resin film is exposed and developed so as to cover at least one of the first and second excitation electrodes of the piezoelectric vibrating plate of the piezoelectric wafer. The resin film is patterned, and the piezoelectric vibrating plate of the piezoelectric wafer on which the photosensitive resin film is patterned is individualized.
[Selection diagram] FIG. 6

Description

The present invention relates to a method for manufacturing a piezoelectric vibration device such as a piezoelectric vibrator and a piezoelectric vibration device.

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 and a method for manufacturing the same.

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

(1) The method for manufacturing a piezoelectric vibrating device according to the present invention includes a step of preparing a piezoelectric wafer in which a plurality of piezoelectric vibrating plates having first and second excitation electrodes formed on both main surfaces are arranged and supported. The step of attaching the photosensitive resin film to at least one of the main surfaces of both main surfaces of the piezoelectric wafer and the exposure and development of the photosensitive resin film attached to the piezoelectric wafer are performed to obtain the piezoelectric wafer. A step of patterning the photosensitive resin film so as to cover at least one of the first and second excitation electrodes of the piezoelectric vibrating plate, and the above-mentioned piezoelectric wafer on which the photosensitive resin film is patterned. It is provided with a step of disassembling the piezoelectric vibrating plate.

According to the method for manufacturing a piezoelectric vibration device according to the present invention, a photosensitive resin film is attached to a piezoelectric wafer in which a plurality of piezoelectric vibration plates having first and second excitation electrodes formed on both main surfaces are arranged and supported. The photosensitive resin film is exposed and developed to be patterned so as to cover at least one of the first and second excitation electrodes of the piezoelectric vibrating plate of the piezoelectric wafer. By this patterning, the piezoelectric vibrating plate is patterned. It is possible to remove unnecessary parts of the photosensitive resin film attached to. In this way, the photolithography technology can remove the unnecessary part of the photosensitive resin film attached to the piezoelectric diaphragm. Therefore, for example, when the unnecessary part of the resin film is cut and removed by laser light, the resin film is used. At the same time, the wiring pattern of the piezoelectric diaphragm is not cut, resulting in poor continuity.

Further, in the process of attaching the photosensitive resin film to the piezoelectric wafer, the photosensitive resin film may be attached to the piezoelectric wafer so as to cover the entire surface thereof, and there is no need for alignment, so that the photosensitive resin film can be attached efficiently. Can be attached.

Further, since the excitation electrode formed on at least one main surface of both main surfaces of the piezoelectric wafer is covered with the photosensitive resin film, the cost is reduced as compared with the configuration in which the excitation electrode is covered with a metal or ceramic lid. can do.

(2) In a preferred embodiment of the present invention, the piezoelectric diaphragm in the step of preparing the piezoelectric wafer has a vibrating portion in which the first and second excitation electrodes are formed, and an outer frame surrounding the vibrating portion. The vibrating portion has a portion, and the vibrating portion is thinner than the outer frame portion. In the step of attaching the photosensitive resin film, the photosensitive resin film is attached to the outside of the piezoelectric diaphragm of the piezoelectric wafer. Paste it on the frame.

According to this embodiment, since the photosensitive resin film is attached to the outer frame portion surrounding the thin-walled vibrating portion, the photosensitive resin film does not come into contact with the thin-walled vibrating portion, and the vibrating portion is excited. The electrodes can be sealed.

(3) In one embodiment of the present invention, the piezoelectric vibrating plate in the step of preparing the piezoelectric wafer is formed with first and second metal films connected to the first and second excitation electrodes, respectively. In the step of patterning the photosensitive resin film, the photosensitive resin film is patterned so that the first and second metal films of the piezoelectric vibrating plate of the piezoelectric wafer are exposed.

According to this embodiment, in the step of patterning the photosensitive resin film, the first and second metal films connected to the first and second excitation electrodes are patterned so as to be exposed, so that the photosensitive resin film is exposed. The first and second metal films not covered with can be used as the first and second mounting terminals, and the first and second mounting terminals are circuited by a bonding material such as solder, metal bumps or wires. The piezoelectric vibration device can be mounted by joining to a substrate or the like. Therefore, unlike the conventional case, it is not necessary to store and mount the piezoelectric vibrating piece in the box-shaped base having the mounting terminal and the upper surface is open, and an expensive base is not required.

(4) In another embodiment of the present invention, the photosensitive resin film in the step of attaching the photosensitive resin film is a photosensitive polyimide film.

According to this embodiment, the photosensitive polyimide film that has been exposed and developed and cured has high heat resistance, so that the resin film is not deformed during the solder reflow treatment for mounting the piezoelectric vibration device. ..

(5) In still another embodiment of the present invention, the piezoelectric diaphragm in the step of preparing the piezoelectric wafer is a quartz diaphragm, and in the step of attaching the photosensitive resin film, the photosensitive resin. A part of the film is attached to the quartz substrate portion of the quartz diaphragm.

When the photosensitive resin film is attached to a metal film forming a wiring pattern formed on a crystal vibrating plate and subjected to exposure development, the metal film may be deteriorated by the moisture transmitted through the exposure-developed photosensitive resin film. However, according to this embodiment, a part of the photosensitive resin film is attached to the crystal substrate portion of the crystal vibrating plate and subjected to exposure development, so that deterioration due to moisture is suppressed as compared with a metal film. Can be done. Further, when the photosensitive resin film is attached to the substrate portion of the crystal and exposed to development, the bonding strength is improved as compared with the case where the photosensitive resin film is attached to a metal film and exposed to development.

(6) 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 obtained by exposing and developing a photosensitive resin film. Is.

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 vibrating plate 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 obtained by exposure-developing a photosensitive resin film, both sealing members are made of a metal or ceramic lid. The cost can be reduced as compared with the configuration of.

(7) In another embodiment of the present invention, 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. The vibrating portion is thinner than the outer frame portion, and the peripheral end portion of at least one of the first and second sealing members is at least on both main surfaces of the outer frame portion. It is joined to one main surface and seals at least one of the first and second excitation electrodes.

According to this embodiment, the photosensitive resin film as a sealing member is bonded to the outer frame portion surrounding the thin-walled vibrating portion, so that the photosensitive resin film does not come into contact with the thin-walled vibrating portion. The excitation electrode of the vibrating portion can be sealed.

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

According to this embodiment, since the first and second metal films are formed on both ends in the direction along the opposite sides of the substantially rectangular shape in the plan view, the first and first metal films on both ends in the direction along the opposite sides are formed. The two metal films can be used as the first and second mounting terminals, and the first and second mounting terminals are joined to a circuit board or the like with a bonding material such as solder, metal bumps, or wires. A piezoelectric vibration device can be mounted.

(9) In one embodiment of the present invention, the piezoelectric diaphragm is a crystal diaphragm, and a part of the resin film obtained by exposure-developing a photosensitive resin film is bonded to a crystal base portion of the crystal diaphragm. There is.

When a resin film obtained by exposure-developing a photosensitive resin film is bonded to a metal film constituting a wiring pattern formed on a crystal vibrating plate, the metal film may be deteriorated by the moisture transmitted through the resin film. According to this embodiment, since a part of the resin film obtained by exposing and developing the photosensitive resin film is bonded to the crystal base portion of the crystal vibrating plate, deterioration due to moisture can be suppressed as compared with the metal film. can. Further, the resin film obtained by exposing and developing the photosensitive resin film has higher bonding strength when it is bonded to the base portion of the crystal than when it is bonded to the metal film.

According to the present invention, a photosensitive resin film is attached to a piezoelectric wafer in which a plurality of piezoelectric vibrating plates having first and second excitation electrodes formed on both main surfaces are arranged and supported, and the photosensitive resin film is exposed. And developed, the photosensitive resin film is patterned so as to cover at least one of the first and second excitation electrodes of the piezoelectric vibrating plate of the piezoelectric wafer. Unnecessary parts can be removed. That is, since the unnecessary part of the photosensitive resin film attached to the piezoelectric diaphragm can be removed by the photolithography technique, the unnecessary part of the resin film can be cut and removed together with the resin film, for example, by laser light or the like. , The wiring pattern of the piezoelectric diaphragm is not cut and conduction failure does not occur.

Further, in the process of attaching the photosensitive resin film to the piezoelectric wafer, the photosensitive resin film may be attached to the piezoelectric wafer so as to cover the entire surface thereof, and there is no need for alignment, so that the photosensitive resin film can be attached efficiently. Can be attached.

Further, since the excitation electrode formed on at least one main surface of both main surfaces of the piezoelectric wafer is covered with the resin film obtained by exposure-developing the photosensitive resin film, the excitation electrode is covered with a metal or ceramic lid. Compared with, the cost can be reduced.

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 the crystal oscillator of FIG. FIG. 3 is a schematic cross-sectional view taken along the line AA of FIG. FIG. 4 is a schematic bottom view of the crystal oscillator of FIG. FIG. 5 is a schematic cross-sectional view schematically showing the manufacturing process of the crystal oscillator of FIG. FIG. 6 is a schematic cross-sectional view schematically showing the manufacturing process of the crystal oscillator of FIG. FIG. 7 is a schematic plan view of an example of a crystal wafer. FIG. 8 is a partially enlarged view of FIG. 7. FIG. 9 is a schematic plan view of a quartz diaphragm constituting the crystal oscillator according to another embodiment of the present invention. FIG. 10 is a schematic bottom view of the crystal diaphragm of FIG. FIG. 11 is a schematic perspective view corresponding to FIG. 1 of still another embodiment of the present invention. FIG. 12 is a schematic cross-sectional view corresponding to FIG. 3 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 piezoelectric vibration device.

1 is a schematic perspective view of a quartz oscillator according to an embodiment of the present invention, FIG. 2 is a schematic plan view thereof, and FIG. 3 is a schematic cross-sectional view taken along the line AA of FIG. Yes, FIG. 4 is a schematic bottom view thereof. In addition, in FIG. 3 and FIGS. 5 and 6 described later, the thickness of the metal film or the resin film is exaggerated for convenience of explanation.

The crystal oscillator 1 of this embodiment is a first sealing member that covers and seals the AT-cut crystal vibrating plate 2 and one main surface side of both the front and back surfaces of the crystal vibrating plate 2. The first resin film 3 obtained by exposure-developing the first photosensitive resin film and the second photosensitive resin film as the second sealing member covering and sealing the other main surface side of the crystal vibrating plate 2 are exposed and developed. The second resin film 4 is provided.

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.

Next, each configuration of the crystal diaphragm 2 and the first and second resin films 3 and 4 constituting the crystal oscillator 1 will be described.

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'axis 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 4) is the X-axis direction, and the long side direction of the crystal diaphragm 2 (left and right in FIGS. 2 and 4). Direction) is the Z'axis direction. The long side direction (Z'axis direction) of the crystal vibrating plate 2 is a direction along the facing side of one of the two sets of facing sides of the crystal vibrating plate 2 having a rectangular plan view, and is the direction of the crystal vibrating plate 2. The short side direction (X-axis direction) is a direction orthogonal to the above-mentioned 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 is thinner than the outer frame portion 23. By joining the peripheral ends of the first and second resin films 3 and 4 to the outer frame portion 23 so as to cover the thin vibrating portion 21, an internal space is formed and sealed.

In this embodiment, 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 thereof, so that the vibrating portion 21 is connected at two or more locations. In comparison, the stress acting on the vibrating portion 21 can be reduced.

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.

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. The outer frame portions 23 at both ends in the long side direction of the rectangular crystal diaphragm 2 in a plan view have the first and second metal films 27, which are electrically connected to the first and second excitation electrodes 25 and 26, respectively. 28 are formed along the short side direction of the crystal diaphragm 2.

As described above, the first and second metal films 27 and 28 are formed by sandwiching the vibrating portions 21 at both ends of the crystal vibrating plate 2 in the long side direction. In this embodiment, the metal films 27 and 28 are used as mounting terminals for mounting the crystal oscillator 1 on a circuit board or the like, as described above.

On one of the two main surfaces, as shown in FIG. 2, the first metal film member 27 is connected to the rectangular annular first sealing pattern 201 described later, and on the other main surface, FIG. 4 As shown in the above, the second metal film 28 is connected to the rectangular annular second sealing pattern 202 described later.

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.

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, a first sealing pattern 201 to which the first resin film 3 is bonded is formed on the surface side of the quartz diaphragm 2 in a rectangular annular shape so as to surround the substantially rectangular vibrating portion 21. ing. The first sealing pattern 201 extends from both ends of the connecting portion 201a connected to the first metal film 27 and both ends of the connecting portion 201a along the long side direction (Z'axis direction) of the quartz diaphragm 2. A second extension that extends along the short side direction (X-axis direction) of the first extension portions 201b, 201b and the crystal diaphragm 2 and connects the extension ends of the first extension portions 201b, 201b. It is provided with a unit 201c. 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 crystal diaphragm 2 and the second metal film 28, and the first sealing is performed. The pattern 201 and the second metal film element 28 are insulated from each other.

As shown in FIG. 4, a second sealing pattern 202 to which the second resin film 4 is bonded is formed on the back surface side of the quartz diaphragm 2 in a rectangular annular shape so as to surround the substantially rectangular vibrating portion 21. ing. The second sealing pattern 202 has a connecting portion 202a connected to the second metal film 28 and a first extending portion 202b extending from both ends of the connecting portion 202a along the long side direction of the quartz diaphragm 2. , 202b and a second extension portion 202c extending along the short side direction of the crystal diaphragm 2 and connecting the extension ends of the first extension portions 202b, 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 crystal 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 a rectangular annular electrodeless region in plan view.

As shown in FIG. 4, 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. 4), which are 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 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 202a 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 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.

As described above, since the first metal films 27 and the second metal films 28 on both main surfaces are electrically connected to each other, the crystal oscillator 1 is connected to the first and second metal films 27, When the 28 is mounted on a circuit board or the like as the first and second mounting terminals, it can be mounted on either of the front and back main surfaces.

The first and second resin films 3 and 4, which are joined to the front and back surfaces of the crystal diaphragm 2 and seal the vibrating portion 21 of the crystal diaphragm 2, are rectangular films. The rectangular first and second resin films 3 and 4 have a size that covers a rectangular region excluding the first and second metal films 27 and 28 at both ends in the longitudinal direction of the crystal diaphragm 2, and the vibrating portion 21. And is joined to the outer frame portion 23 of the crystal diaphragm 2 so as to cover the rectangular region around the same.

In this embodiment, the first and second resin films 3 and 4 are made by exposing and developing a photosensitive resin film, for example, a photosensitive polyimide film as described later, forming a pattern, and curing the photosensitive resin film.

Since the photosensitive polyimide film that has been exposed and developed and cured has a heat resistance of 300 ° C. or higher, the first and second resin films 3 and 4 are used during the solder reflow treatment for mounting the crystal oscillator 1. There is no deformation.

The first and second resin films 3 and 4 of this embodiment are transparent, but may be translucent or opaque.

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 photosensitive polyimide film 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.

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

5 and 6 are schematic cross-sectional views schematically showing a process of manufacturing the crystal oscillator 1.

First, the unprocessed crystal plate (AT-cut crystal plate) 5 shown in FIG. 5 (a) is subjected to, for example, wet etching using photolithography technology and etching technology, and FIG. 5 (b) shows. As shown, the outer shape of each part such as a plurality of crystal diaphragms 2a and a frame portion (not shown) supporting them is formed, and further, the outer frame portion 23a and the outer frame portion 23a are formed on the crystal diaphragm 2a. Also forms the outer shape of each part such as the thin-walled vibrating part 21a. That is, the processing process of the outer shape and the vibrating portion is carried out.

Next, as shown in FIG. 5 (c), the first and second excitation electrodes 25a, 26a and the first 1, are placed at a predetermined position on the crystal vibrating plate 2a by the sputtering technique, the vapor deposition technique, and the photolithography technique. An electrode forming step for forming the second metal films 27a, 28a and the like is carried out.

In this way, a plurality of quartz diaphragms 2a on which the first and second excitation electrodes 25a and 26a are formed and the first and second metal films 27a and 28a are formed are arranged and supported in a matrix. The crystal wafer 5a is prepared.

FIG. 7 is a schematic plan view showing an example of the crystal wafer 5a of FIG. 5 (c), and FIG. 8 is a schematic plan view showing a part thereof in an enlarged manner.

In the crystal wafer 5a, the vibrating portions 21a on which the first and second excitation electrodes 25a and 26a are formed and a plurality of crystal diaphragms 2a on which the first and second metal films 27a and 28a are formed are arranged in a matrix. It is configured to be supported by the frame portion 9 via the connecting portion 8. The periphery of each crystal diaphragm 2a is a penetrating portion 15 except for the connecting portion 8.

In the method for manufacturing the piezoelectric vibration device of this embodiment, as described above, a crystal in which a plurality of crystal vibrating plates 2a having first and second excitation electrodes 25a, 26a and the like formed on both main surfaces are supported in an array. A step of preparing the wafer 5a, a step of attaching a photosensitive polyimide film which is a photosensitive resin film to both main surfaces of the crystal wafer 5a, and a step of exposing and exposing the photosensitive polyimide resin film attached to the crystal wafer 5a. A step of patterning the photosensitive polyimide film so as to cover the first and second excitation electrodes 25a and 26a of the crystal vibrating plate 2a of the crystal wafer 5a by developing, and a step of curing the patterned photosensitive polyimide resin film. And the step of breaking off each crystal vibrating plate 2a from the crystal wafer 5a obtained by curing the photosensitive polyimide resin film and disassembling the pieces.

Hereinafter, each step will be described.

As shown in FIG. 5D, the photosensitive polyimide films 3a and 4a are attached, that is, laminated to the entire surfaces of both main surfaces of the crystal wafer 5a prepared as described above. The laminating of the photosensitive polyimide films 3a and 4a on the crystal diaphragm 2a is performed in an atmosphere of an inert gas such as nitrogen gas. This laminating is not limited to the atmosphere of an inert gas, but may be performed in an atmosphere or a reduced pressure atmosphere.

In this embodiment, the laminate is, for example, drawn out from the photosensitive polyimide films 3a and 4a wound in a roll shape, respectively, and is shown in FIG. 7 between the drawn photosensitive polyimide films 3a and 4a. Pressurize with a thermal roller so as to sandwich the crystal wafer 5a, and the photosensitive polyimide resin films 3a and 4a are attached to the entire surfaces of both main surfaces of the crystal wafer 5a, respectively. As described above, since the photosensitive polyimide resin films 3a and 4a may be attached to the entire surface of the crystal wafer 5a, it is not necessary to align them and they can be efficiently laminated. The laminating is not limited to the roll type, but may be a single-wafer type.

Next, as shown in FIG. 6 (e), the photosensitive polyimide films 3a and 4a attached to both main surfaces of the crystal wafer 5a are exposed via the photomask 11.

In this exposure, the vibrating portion 21a on which the first and second excitation electrodes 25a and 26a are formed and the rectangular region around the vibrating portion 21a become the exposed portion, and the first and second metal films 27 and 28 other than the rectangular region are exposed. The area including the above is exposed so as to be an unexposed portion.

After that, development is performed to dissolve and remove the unexposed portion in a developing solution, and as shown in FIG. 6 (f), the vibrating portion in which the first and second excitation electrodes 25a and 26a of each crystal diaphragm 2a are formed. The resin films 3 and 4 are patterned so as to leave only the exposed portion covering 21a and the rectangular area around it.

Then, the resin films 3 and 4 are thermally cured by heating at about 300 ° C., and as shown in FIG. 6 (g), each crystal diaphragm 2a is cut off from the crystal wafer 5 and separated into individual pieces.

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

As described above, in the present embodiment, the photosensitive polyimide films 3a and 4a are formed on both main surfaces of the crystal wafer 5a in which a plurality of crystal diaphragms having the first and second excitation electrodes formed on both main surfaces are arranged and supported. The photosensitive polyimide films 3a and 4a are exposed and developed, respectively, and patterned so as to cover the vibrating portion 21a on which the first and second exciting electrodes 25a and 26a of the crystal vibrating plate 2a of the crystal wafer 5a are formed. Then, unnecessary regions including the first and second metal films 27 and 28 are removed. As a result, a non-photosensitive resin film is bonded to the crystal wafer, and the wiring pattern of the crystal diaphragm is cut together with the resin film, for example, when the unnecessary portion of the resin film is cut and removed by laser light. Therefore, there is no possibility of poor continuity.

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 crystal vibrating plate 2, the crystal oscillator 1 is made of an insulating material such as ceramic. A box-shaped base with an open upper surface is used to store and mount a piezoelectric vibrating piece, and an expensive base or lid is not required as in the conventional example in which a lid is joined to the opening and sealed tightly. There is no need to mount the piezoelectric vibrating piece on the base.

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 piezoelectric vibrating piece is stored and mounted on a box-shaped base having an open upper surface and sealed with a 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 is formed in a rectangular annular shape on one of the main surfaces of the crystal diaphragm 2 so as to surround the substantially rectangular vibrating portion 21. As shown in FIG. 4, a second sealing pattern 202 is formed in a rectangular ring shape on the other main surface of both main surfaces of the crystal diaphragm 2 so as to surround the substantially rectangular vibrating portion 21. , The first and second sealing patterns 201 and 202 having a rectangular annular shape may be omitted.

9 and 10 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. 9, 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. 10, 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 this embodiment, since the rectangular annular _first and second sealing patterns 201 and 202 are omitted, most of the photosensitive polyimide films 3a and 4a are the crystal base portion 14 of the crystal diaphragm 21. It will be affixed to, exposed and developed, and cured.

In the above embodiment, most of the photosensitive polyimide films 3a and 4a are attached to the first and second sealing patterns 201 and 202 made of a metal film, and exposed and developed and cured, the first and second resins. Moisture that has passed through the films 3 and 4 may deteriorate the first and second sealing patterns 201 and 202 made of the metal film, and the adhesive force with the first and second resin films 3 and 4 may decrease.

On the other hand, according to the present embodiment, the photosensitive polyimide films 3a and 4a are attached to the crystal base portion ₁₄ of the crystal diaphragm 21 for exposure development and curing, and the moisture content is like a metal film. Deterioration due to Further, according to the present embodiment in which the resin films 3 and 4 obtained by exposing and developing the photosensitive polyimide films 3a and 4a are bonded to the crystal base portion 14, the first and second sealing patterns 201 and 202 made of a metal film are bonded. In addition, the bonding strength is improved as compared with the above-described embodiment in which the resin films 3 and 4 obtained by exposing and developing the photosensitive polyimide films 3a and 4a are bonded.

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. 11 and FIG. 12.

11 and 12 are schematic perspective views and schematic cross-sectional views of the crystal oscillator 11 corresponding to FIGS. ₁ and 3, respectively. 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 crystal diaphragm 2 ₂ are formed and the rectangle around the vibrating portion 21 ₁ . 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. 12, 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 crystal 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. 3 and 12, 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, 4; 3 ₁ , 4 ₁ are bonded to both main surfaces of the crystal diaphragms 2, 2 ₁ and 2 ₂ , respectively, and the vibrating portions 21 and 21 ₁ are joined. However, a resin film is bonded to only one main surface of the crystal diaphragms 2, 2 ₁ , 2 ₂ and a conventional lid is bonded to the other main surface to vibrate the vibrating parts 21, 21 ₁ . May be sealed.

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 a piezoelectric vibrator such as a crystal oscillator, and may be applied to other piezoelectric vibration devices such as a piezoelectric oscillator.

1, 1 ₁ Crystal oscillator 2, 2 ₁ , 2 ₂ Crystal vibrating plate 3, 3 ₁ 1st resin film 4, 4 ₁ 2nd resin film 5 Crystal plate 5a Crystal wafer 17 1st mounting terminal 18 2nd mounting terminal 21 , 21 ₁ Vibration part 22, 22 ₁ Penetration part 23, 23 ₁ Outer frame part 24, 24 ₁ Connection part 25, 25 ₁ First excitation electrode 26, 26 ₁ Second excitation electrode 27, 27 ₁ First metal film 28, 28 ₁ 2nd metal film 201 1st sealing pattern 202 2nd sealing pattern

Claims (9)

A process of preparing a piezoelectric wafer in which a plurality of piezoelectric diaphragms having first and second excitation electrodes formed on both main surfaces are arranged and supported, and a process of preparing a piezoelectric wafer.
A step of attaching a photosensitive resin film to at least one of the two main surfaces of the piezoelectric wafer,
The photosensitive resin film attached to the piezoelectric wafer is exposed and developed so as to cover at least one of the first and second excitation electrodes of the piezoelectric vibrating plate of the piezoelectric wafer. The process of patterning the photosensitive resin film and
The present invention comprises a step of disassembling the piezoelectric diaphragm of the piezoelectric wafer on which the photosensitive resin film is patterned.
A method for manufacturing a piezoelectric vibration device. The piezoelectric diaphragm in the step of preparing the piezoelectric wafer has a vibrating portion in which the first and second excitation electrodes are formed, and an outer frame portion surrounding the vibrating portion. It is thinner than the outer frame and
In the step of attaching the photosensitive resin film, the photosensitive resin film is attached to the outer frame portion of the piezoelectric diaphragm of the piezoelectric wafer.
The method for manufacturing a piezoelectric vibration device according to claim 1. The piezoelectric diaphragm in the step of preparing the piezoelectric wafer is formed with first and second metal films connected to the first and second excitation electrodes, respectively.
In the step of patterning the photosensitive resin film, the photosensitive resin film is patterned so that the first and second metal films of the piezoelectric diaphragm of the piezoelectric wafer are exposed.
The method for manufacturing a piezoelectric vibration device according to claim 1 or 2. The photosensitive resin film in the step of attaching the photosensitive resin film is a photosensitive polyimide film.
The method for manufacturing a piezoelectric vibration device according to any one of claims 1 to 3. The piezoelectric diaphragm in the step of preparing the piezoelectric wafer is a crystal diaphragm.
In the step of attaching the photosensitive resin film, a part of the photosensitive resin film is attached to the crystal base portion of the crystal diaphragm.
The method for manufacturing a piezoelectric vibration device according to any one of claims 1 to 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 obtained by exposure-developing a photosensitive resin film.
A piezoelectric vibration device characterized by that. 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 at least one of the first and second sealing members is joined to at least one main surface of both main surfaces of the outer frame portion, and the first and second excitation electrodes are joined. Seal at least one of the excitation electrodes,
The piezoelectric vibration device according to claim 6. The piezoelectric diaphragm is 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 is the first. 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 6 or 7. The piezoelectric diaphragm is a crystal diaphragm, and a part of the resin film obtained by exposure-developing a photosensitive resin film is bonded to a crystal substrate portion of the crystal diaphragm.
The piezoelectric vibration device according to any one of claims 6 to 8.

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