JP2002084160A - Piezoelectric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric device of a structure where a cantilever fixing, which can be supported by only the fixed end part of a piezoelectric vibrator of a bump is made possible, and a stable vibrating space can be achieved between a substrate and the vibrator. SOLUTION: A bump 5a, extending counterposed to the inner wall surface 27a of a container 2 in closer to exciting electrodes 31 and 33 on a piezoelectric vibrator 3 is formed between the lower surface on the side of the short side on one side of the short sides of the vibrator 3 and electrode pads 22, and 23 and at the same time, a conductive adhesive member 4 is formed on the pads 31 and 33, extending from the bump 5a to the inner wall surface 27a of the container 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric device in which a piezoelectric vibrator is joined to a substrate of a container or the like via a conductive adhesive member obtained by curing a conductive resin paste.

[0002]

2. Description of the Related Art A crystal oscillator, which is an example of a conventional piezoelectric device, has already been known as shown in FIGS. The crystal oscillator 51 includes a ceramic package 52,
It is mainly composed of a crystal unit 53 and a conductive adhesive member 56. As shown in FIG. 11, the quartz resonator 53 has excitation electrodes 54a and 54c attached to both main surfaces of a strip-shaped quartz substrate. Also, on the lower surface on one short side of the quartz substrate, a lead electrode 5 extending from each of the excitation electrodes 54a and 54c is provided.
4b and 54d are attached. One short side of the quartz substrate is called a fixed end, and the other short side is called a free end. Further, the ceramic package 52 includes the quartz oscillator 5.
The substrate 52 has a substrate 52a on which the substrate 3 is mounted. On the surface of the substrate 52a, electrode pads 55, 55 are formed so as to face the extraction electrodes 54b, 54d of the crystal unit 53.

At substantially the center of the electrode pads 55, connection support bumps 57 are formed. A holding bump 58 is also formed on the free end side of the crystal unit 53 of the substrate 52a.

The substrate 52a and the crystal unit 53 are fixed on the electrode pads 55, 55 on which the bumps 57 are formed, by applying a conductive resin paste to be a conductive adhesive member 56 to fix the crystal unit 53. End side is bump 5 for connection support
7, the free end side is arranged so as to be placed on the holding bump 58, and by curing the conductive resin paste,
It is mechanically joined and electrically connected.

The ceramic package 52 is formed by laminating ceramic insulating plates of alumina or the like, and has a cavity 52e for accommodating a quartz oscillator 53 therein. The substrate serving as the bottom surface of the cavity 52e is the substrate 52a on which the above-described quartz oscillator 53 is mounted.

Although not shown in the figure, external terminal electrodes connected to the electrode pads 55 are formed on the outer surface of the ceramic package 52. Further, a seal ring 52d for connecting the metal lid 59 by seam welding is provided around the opening of the cavity 52e of the ceramic package 52. After the crystal oscillator 53 is accommodated in the cavity 52e, the lid 5 is placed on the ceramic package 52 in order to hermetically seal the crystal oscillator 53.
9 had been deposited.

[0007]

The above-described quartz oscillator 53
Both ends in the longitudinal direction, that is, both the fixed end and the free end are supported or held by bumps 57 and 58. Thus, a vibration space corresponding to the height of the bumps 57 and 58 is formed between the surface of the substrate 52a and the lower surface of the crystal unit 53.

However, the free end of the crystal unit 53 is fixed or in contact with any object, so that the characteristics of the crystal unit 53 are deteriorated.

Ideally, the crystal oscillator vibrates in a portion where the excitation electrodes face each other. However, in practice, a small amount of the vibration leaks to the periphery of the excitation electrode, and as described above, If it sticks or comes into contact with any object, it hinders ideal vibration and leads to deterioration of characteristics.

The present invention has been devised in view of the above-mentioned problems, and has as its object to achieve cantilever fixing that can be joined and supported only by the fixed end of a piezoelectric vibrator. An object of the present invention is to provide a piezoelectric device capable of forming a stable vibration space between the piezoelectric device and a piezoelectric vibrator. At the same time, it is another object of the present invention to provide a piezoelectric device which can secure the same or higher strength as compared with the conventional one with respect to the application amount of the conductive resin paste.

It is another object of the present invention to provide a piezoelectric device which can improve the bonding strength between a piezoelectric vibrator and a substrate with a simple structure.

It is another object of the present invention to provide a piezoelectric device in which a conductive adhesive member can be easily formed without causing a short-circuit problem even if the size of the substantially rectangular container is shortened in the longitudinal direction to reduce the size. It is in.

[0013]

According to the present invention, there is provided a rectangular piezoelectric substrate having excitation electrodes formed on both main surfaces thereof, connected to the excitation electrodes on one lower side of the lower surface, and separated in the width direction. And a container having a rectangular cavity, and a pair of electrode pads provided on one short side of the bottom surface of the cavity. The piezoelectric vibrator is provided in the cavity of the container. In the piezoelectric device in which the pair of extraction electrodes of the piezoelectric vibrator and the pair of electrode pads are connected via a conductive adhesive member while accommodating, the exciter electrode of the piezoelectric vibrator on the electrode pad, A bump extending in the width direction of the piezoelectric vibrator is formed, and the conductive adhesive member is disposed between the bump and an inner wall surface on one short side of a cavity provided in the container. Piezo device A.

According to another aspect of the present invention, a pair of extraction electrodes are formed on both main surfaces of a rectangular piezoelectric substrate and connected to the excitation electrode on one lower side of the lower surface, and separated in the width direction. And a container having a rectangular cavity, and a pair of electrode pads provided on one short side of the bottom surface of the cavity, and accommodating the piezoelectric oscillator in the cavity of the container. In a piezoelectric device in which a pair of extraction electrodes of the piezoelectric vibrator and the pair of electrode pads are connected via a conductive adhesive member, the piezoelectric vibrator is disposed on the electrode pad near an excitation electrode of the piezoelectric vibrator. Forming a bump extending in the width direction of the electrode pad, between the upper surface of the electrode pad and the piezoelectric vibrator, disposing the conductive adhesive member in a region from the bump to one short side of the piezoelectric vibrator; Conductivity A piezoelectric device which is characterized in that is provided an insulating adhesive member between one inner wall surface of the short side of the cavity provided in Chakubuzai the container.

According to the present invention, an electrode pad having continuous or intermittent bumps extending in the width direction of the piezoelectric vibrator is formed on the surface of the substrate, which is the bottom surface of the container. In addition, the bump is disposed on the electrode pad near the excitation electrode of the piezoelectric vibrator.

In the piezoelectric vibrator, a conductive adhesive member obtained by curing a conductive resin paste is interposed between one short side, that is, the lower surface of the fixed end, and the electrode pad. The adhesive member is formed from the bump to the inner wall surface of the container.

The bump extending in the short side direction of the piezoelectric vibrator acts as a spacer for securing a vibration space between the piezoelectric vibrator and the substrate, as in the prior art.

The bumps are formed by the conductive resin paste supplied on the electrode pads being closer to the center of the piezoelectric vibrator, that is,
It acts as a dam that suppresses spreading to the vicinity of the excitation electrode.

Further, the bumps serve as levers for supporting the piezoelectric vibrator in a cantilever fixed structure. The fixed end of the piezoelectric vibrator is a leverage point where a shrinkage stress is generated when the conductive resin paste is cured. Accordingly, the bump lifts the free end of the piezoelectric vibrator as a fulcrum of the lever. Thus, the cantilever fixing structure of the piezoelectric vibrator can be reliably achieved, and the free end side of the piezoelectric vibrator does not adhere to or touch any object at all.

In general, when a shock such as a drop is applied to the crystal oscillator, the influence on the piezoelectric vibrator concentrates on the boundary line of the presence or absence of the conductive adhesive member at the fixed end, and thereafter, the piezoelectric vibrator is not affected. It gradually propagates to the tip of the free end. That is, the distortion of the piezoelectric vibrator moves to the tip of the free end. In order to prevent the piezoelectric vibrator from touching the substrate while the vibration propagates and reaches the free end of the piezoelectric vibrator, a sufficient gap is provided between the piezoelectric vibrator and the substrate. Required. In the fixing method of the present invention, a sufficient height is obtained, even when an external impact is applied due to dropping or the like, even if the bonding portion between the piezoelectric vibrator and the conductive adhesive member other than the electrode pad slightly peels off. A large change in the oscillation frequency can be prevented.

Further, a conductive adhesive member is provided on the electrode pad between the bump extending in the short side direction of the piezoelectric vibrator and a side wall of a container formed of a ring-shaped ceramic layer close to the electrode pad. With this configuration, the conductive adhesive member can be securely bonded to the end surface of the fixed end of the piezoelectric vibrator.

That is, the conductive resin paste is supplied between the bump and the inner wall surface of the container. When the piezoelectric vibrating element is mounted, the conductive resin paste is applied to the end face of the fixed end of the piezoelectric vibrator. And rises more than the supply height on the electrode pad. Due to the swelling, the conductive resin paste can surely adhere to the end face of the piezoelectric vibrator. Then, by the curing of the conductive resin paste, the cantilever fixing structure of the quartz oscillator can be achieved as described above, and a strong contraction stress acts.

In any of the examples, the conductive adhesive member is bonded not only to the lower surface of the fixed end of the piezoelectric vibrator but also to the end surface. As a result, the bonding strength is dramatically improved. .

In one example, since the conductive adhesive member is provided between the upper surface of the electrode pad and the piezoelectric vibrator in a region from the bump to one short side of the piezoelectric vibrator, the crystal is formed by the bump. The electrically conductive adhesive does not spread to the excitation electrode of the vibrator, making the electrical connection reliable, and an insulating adhesive member between the conductive adhesive member and the inner wall surface on one short side of the cavity provided in the container. Is disposed, during the bonding process of the insulating adhesive member, the insulating resin paste creeps up on the inner wall surface of the container and rises above the supply height on the electrode pad, and the insulating resin paste is applied to the end face of the piezoelectric vibrator. The paste will surely adhere.

Therefore, the electrical connection is made of a conductive adhesive member,
In addition, the mechanical connection between the piezoelectric vibrator and the container is separated by an insulating adhesive member, which separates the functions of electrical connection and mechanical connection, so that a short circuit between electrode pads and other internal wiring is likely to occur. Electrical short circuit around the outside of the vibrator can be reliably prevented. Also, regarding the swelling on the seal ring, since the conductive adhesive member does not swell and the insulating adhesive member swells, short-circuiting does not occur even when the seal ring arranged on the side wall of the container is contacted. Can be easily reduced in thickness.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a piezoelectric device according to the present invention will be described in detail with reference to the drawings. In the description, a piezoelectric device using a quartz oscillator as a piezoelectric oscillator (hereinafter, a quartz oscillator including a quartz oscillator alone or an oscillator circuit) will be described.

FIG. 1 is a sectional structural view of a crystal oscillator which is a piezoelectric device according to the present invention, and FIG. 2 is a top view in a state where a cover is omitted. FIG. 3 is a plan view showing the crystal resonator and the conductive adhesive member. In FIG. 2, the crystal oscillator is shown in a transparent manner in order to facilitate understanding of the positional relationship among the crystal oscillator, the conductive adhesive member, and the bumps.

The crystal oscillator 1 includes a container 2 having a substrate 21, a crystal oscillator 3, a conductive adhesive member 4 and a lid 6.

The container 2 includes a rectangular single-plate ceramic substrate 2
1, a ring-shaped ceramic layer 27 which is a side wall of the container 2 provided around the ceramic substrate 21, and a seal ring 25 formed on the upper surface thereof. The seal ring 25 is made of Fe-Ni, Fe-Ni-Co
And is brazed and fixed to the upper surface of the ring-shaped ceramic layer 27 via the sealing conductor film 24.
As a whole, as shown in FIG. 1, a rectangular cavity portion 20 having an opening on the front surface side and accommodating the crystal resonator 3 is formed. Further, on the bottom surface of the cavity portion 20, that is, on one short side (the left side in FIG. 2) of the surface of the substrate 21, a pair of electrode pads 22 and 23 for electrically connecting to the crystal resonator 3 are formed. Have been. The electrode pads 22 and 23 are separately formed in the width direction of the short side (the vertical direction in FIG. 2). Its shape is substantially rectangular.

External terminal electrodes 26 are formed on the bottom surface of the container 2 to be electrically connected to the electrode pads 22 and 23 and to be connected to an external circuit board. The electrode pads 22 and 23 and the external terminal electrode 26 are connected by a via-hole conductor penetrating a part of the container 2. When the electrode pads 22 and 23 do not correspond to the positions where the external terminal electrodes 26 are formed, if a wiring conductor having a predetermined shape is formed on the bottom surface of the cavity portion 20, the connection can be easily performed by the via hole conductor. In addition, the substrate 21 may have a laminated structure, and internal wiring may be formed between insulating layers.

On the electrode pads 22 and 23, band-like bumps 5 extending toward the center of the cavity 20 and in the short side direction of the crystal unit 3, that is, extending in the vertical direction in the drawing.
Are formed facing the ring-shaped ceramic layer 27. The bumps 5 are formed, for example, by printing a conductive resin paste.

The above-described electrode pads 22 and 23, the sealing conductor film 24 and the bumps 5 are made of a metal such as molybdenum or tungsten. These conductors (electrode pads 22,
23, the conductor film 24, and the bumps 5) are formed on the surface of the substrate 21 by baking a conductive paste, and then the surfaces are plated with Ni or Au. The electrode pads 22, 2
3 and the bumps 5, the conductors serving as the underlying conductor layers of the electrode pads 22 and 23 are formed by printing with the above-mentioned metal paste, and after drying, the surface is again coated with the above-mentioned metal paste according to the shape of the bumps 5. After printing and forming, both are collectively baked and then plated.

The thickness of these conductors (electrode pads 22 and 23, conductor film 24, bump 5) is about 10 to 30 μm, whereby the height of bump 5 is 20 to 60 μm from the surface of substrate 21. Height.

As shown in FIG. 3, the quartz oscillator 3 is formed on a rectangular quartz substrate 30 cut (AT cut) in accordance with a predetermined crystal azimuth, for example, and is adhered to both main surfaces of the quartz substrate 30. Excitation electrodes 31 and 33 and a pair of excitation electrodes 3
Extraction electrodes 32 and 34 extending from the reference numerals 1 and 33 in the short side direction of the quartz substrate 30, respectively. For example, the extraction electrode 32 extending from the excitation electrode 31 on the upper surface extends near the short side of the upper surface, and extends through one long side end surface (the lower end surface in the drawing) near the short side. Is extended to the side. Conversely, the extraction electrode 34 extending from the excitation electrode 33 on the lower surface extends near the short side of the lower surface, and via the other long side end surface (the upper end surface in the drawing) near the short side. It extends to the upper surface side. Thus, the extraction electrodes 32, 34
Are formed on both main surfaces on the fixed end side of the crystal unit 3. The shapes of the extraction electrodes 32 and 34 are
Is arranged at a predetermined position, and has a shape corresponding to the electrode pads 22 and 23.

The extraction electrodes 32, 34 extending to the lower surface of the fixed end of the crystal unit 3 are arranged so as to face the electrode pads 22, 23 formed on the surface of the substrate 21. It is fixed and electrically connected by the adhesive member 4. That is, the bump 5 is interposed between the lower surface of the fixed end of the crystal unit 3 and the electrode pads 22 and 23. Such excitation electrodes 31, 33 and extraction electrode 3
Numerals 2 and 34 are formed of a metal such as Au, Ag, or Cr by arranging a mask having a predetermined shape on the upper and lower surfaces of the quartz substrate 30 and using a method such as vapor deposition or sputtering.

The electrode pads 22 and 23 of the substrate 21 constituting the container 2 and the extraction electrodes 32 and 3 of the crystal unit 3
The conductive adhesive member 4 that electrically connects and mechanically fixes the conductive material 4 is made of a conductive material obtained by mixing a resin such as a silicon-based, epoxy-based, or polyimide-based material that shrinks during curing and Ag powder. It is a resin paste. Then, the conductive resin paste is cured to form the conductive adhesive member 4.

When bonding the crystal resonator 3 and the substrate 21 using the conductive resin paste, first, the conductive resin paste is applied to the electrode pads 22 and 23 on the surface of the substrate 21 by a dispenser or the like. Supply. After that, the crystal oscillator 3 is brought into contact with the raised conductive resin paste on the electrode pads 22 and 23 such that the extraction electrodes 32 and 34 extending from the lower surface on the fixed end side of the crystal oscillator 3 abut.
Is placed. Subsequently, the conductive resin paste is cured.
Note that the conductive resin paste is supplied so as to cover the inner wall surface of the ring-shaped ceramic layer 27 on the outer side with the bump 5 as a boundary.

The metal lid 6 is made of substantially flat metal,
For example, Fe-Ni alloy (42 alloy) or Fe-Ni-
It is made of a Co alloy (Kovar) or the like. Such a metal lid 6 hermetically seals the accommodation area of the crystal unit 3 with nitrogen gas, vacuum, or the like. This metal lid 6
Is placed on the seal ring 25 of the container 2 and seam welding is performed by applying a predetermined current so that the metal on the surface of the seal ring 25 and the metal of the metal lid 6 are welded.
In addition, in order to perform this welding reliably, an Ag brazing layer or the like is previously formed on the joining surface side of the metal lid 6. Also,
A Ni plating layer is formed on the surface side of the metal lid 6 so that the brazing material melted by the welding does not flow around to the surface side of the metal lid 6 and the brazing material contributing to the joining does not decrease. deep.

According to the present invention, the crystal oscillator 3 is
Contraction stress acts when the conductive resin paste supplied to the fixed end side of the resin hardens. Since the bumps 5 support the lower surface side of the crystal unit 3, this supporting portion serves as a fulcrum of the lever, and the fixed end of the crystal unit 3 has a force point (shrinkage stress when the conductive resin paste cures and contracts). Become. as a result,
According to the principle of leverage, the free end of the crystal unit 3 is lifted up, and the crystal unit 3 has a cantilever fixed structure.

Lifting the free end of the crystal unit 3,
In order to form a space required for vibration between the lower surface of the crystal unit 3 and the surface of the substrate 21, the width of the bump 5 should be 10 to 20 μm.
m and the height is 15 μm or more.

It is necessary to pay particular attention to the height. This is because when a shock such as a drop of the crystal oscillator is applied, the crystal resonator 3 cantilevered to the substrate 21
The stress concentrates on the boundary line where the conductive adhesive member 4 exists, and then gradually propagates to the tip of the free end of the crystal unit 3. At this time, it is important that the crystal resonator 3 does not touch the surface of the substrate 21.

Further, the conductive resin paste contains particles of a metal such as Ag or Au for imparting conductivity.
Moreover, it contains metal particles of various particle sizes. And
When the gap between the electrode pads 22 and 23 and the crystal resonator 3 is small (the bump 5 is low), the conductive resin existing in the gap after the crystal resonator 3 is mounted on the electrode pads 22 and 23 on the substrate 21. A phenomenon occurs where the paste keeps moving for several minutes. This is because the pressure when the crystal resonator 3 is mounted cannot be released instantaneously, and the solvent component contained in the conductive resin paste is slowly released. Then, voids are generated in the conductive resin paste due to this phenomenon, and connection reliability and bonding reliability are reduced. However, by setting the height of the bumps 5 to 15 μm or more, the above phenomenon can be effectively suppressed.

As described above, in the crystal oscillator shown in FIGS. 1 and 2, the bumps 5 extending in the short side direction of the crystal unit 3 are provided.
Functions as a spacer for securing a vibration space between the crystal resonator 3 and the substrate 21. In addition, electrode pad 2
It is possible to prevent the conductive resin paste supplied on 2 and 23 from spreading to the center of the crystal unit 3, that is, to the vicinity of the excitation electrode 33. Further, the quartz oscillator 3
Acts as a fulcrum of a lever for making the cantilever fixed structure.

Thus, contact of the crystal unit 3 with the substrate 21 is prevented, and stable bonding is obtained. At the same time, a reliable cantilever fixing structure of the crystal unit 3 can be realized. As a result, contact between the crystal unit 3 and any object can be effectively suppressed, and stable oscillation characteristics can be obtained.

Also, as shown in FIGS. 1 and 2, the ring-shaped ceramic layer 27 is installed such that the inner wall surface 27a faces the bump 5. That is, the inner wall surface 27a of the container 2 facing the bump 5a enters the cavity portion 20 side from a position corresponding to the seal ring 25, whereby the conductive adhesive member 4 can be formed away from the seal ring 25. And reliability is improved.

This structure is a structure for preventing deterioration of characteristics due to external stress such as an impact at the time of a drop and stabilizing a joint portion. The conductive adhesive member 4 is attached and fixed not only to the lower surface of the crystal unit 3 but also to the end surface of the fixed end of the crystal unit 3 and the inner wall surface 27a of the ring-shaped ceramic layer 27.

In such a crystal oscillator having the bump 5 and the inner wall surface 27a of the ring-shaped ceramic layer 27,
As shown in FIG. 4A, after supplying the conductive resin paste to the outside of the bump 5, the quartz oscillator 3 is mounted on the bump 5.

At this time, as shown in FIG. 4 (b), the conductive resin paste raised above the bumps 5 is pressed against the crystal unit 3, and the conductive resin paste loses its place. As a result, the conductive resin paste
From the gap between the inner wall surface 27a located outside the crystal unit 3 and the fixed end of the crystal unit 3, it rises upward and tries to crawl on the inner wall surface 27a.

As described above, the conductive resin paste swells outside the fixed end of the crystal unit 3. Due to the swelling, the conductive resin paste can crawl up to the end face on the fixed end side of the crystal unit 3 (FIG. 4).
(C)).

The above-mentioned inner wall surface 27a is shown in FIGS.
In order to achieve the effect shown in FIG. 3C, the object is to avoid contact with the crystal resonator 3. Thereby, the damping of the fundamental wave vibration can be effectively suppressed.

Next, another embodiment is shown in FIGS. In this embodiment, the bumps 5 formed on the electrode pads 22 and 23 are formed.
The application on the top is the same as the above-described invention, but the size of the application is as follows. When the quartz oscillator 3 is viewed from the top as shown in FIG. The conductive adhesive member 4 is provided in the region extending to the side, but a small amount may be used as long as the extraction electrode on the lower surface side of the crystal unit 3 and the bump 5 are completely in contact. Then, an insulating adhesive member 42 is disposed between the conductive adhesive member 41 and the inner wall surface on one short side of the cavity 20 provided in the container 2. It is preferable that both the conductive adhesive member 41 and the insulating adhesive member 42 are connected in a paste state and then simultaneously cured.

As a result, the electrical connection is made by the conductive adhesive member, and the mechanical connection is mostly made by the insulative adhesive member, and a short circuit is caused by contact between the electrode pads and between the electrode pads and the seal ring. Can be prevented.

FIG. 8 shows still another embodiment. In this embodiment, an opening is formed by using a ring-shaped ceramic layer 2b as the ceramic package 2, and a sealing conductor 2c is formed on the upper surface of the opening. As the metal lid 6b, one having a brazing material layer formed on both surfaces or a surface joined to the upper surface of the opening of the ceramic package is used. In this case, it is a ceramic package that does not use a seal ring, and the conductive adhesive member 4
Not only can the risk of short-circuiting of the metal cover 1 due to the bulge 1 rise in the height direction of the cavity 20, but also the thickness of the crystal oscillator can be further reduced.

The above-described crystal oscillator is formed as follows. First, the excitation electrodes 3 are provided on both main surfaces of the quartz substrate 30.
1. A quartz oscillator 3 having extraction electrodes 32 and 34 formed on the lower surface of the fixed end portion is prepared. At the same time, the container 2 on which the electrode pads 22 and 23, the ring-shaped ceramic layer 27, the sealing conductor film 24 and the seal ring 25 are formed, and the metal lid 6 are prepared. Next, the electrode pads 22, 2
A conductive resin paste for forming the conductive adhesive member 4 is supplied and applied to the substrate 3 with a dispenser or the like. At this time, the conductive resin paste supplied on the electrode pads 22 and 23 has a substantially hemispherical shape in which the whole is raised.

Next, the fixed end portion of the crystal unit 3 is placed on a conductive resin paste which is raised substantially in a hemispherical shape. As a result, the extraction electrode 3 located at the fixed end of the crystal unit 3
2, 34 and the conductive resin paste on the electrode pads 22, 23 come into contact with each other.

It should be noted that the bonding strength of the crystal unit 3 was improved,
In addition, in order to increase the shrinkage stress of the conductive resin paste, the conductive resin paste adheres not only to the short-side end face of the crystal unit 3 but also to the peripheral long-side end face.

The inner wall surface 27a of the ring-shaped ceramic layer 27 has a role of causing the conductive resin paste to crawl on the end face in the short side direction of the crystal unit 3. Therefore, the conductive adhesive member 4 is formed between the short side end face of the crystal unit 3 and the ring-shaped ceramic layer 27, and the conductive adhesive member 4 is formed on the short side lower surface and the end face of the crystal unit 3. The desired strength can be secured by bonding to both. Further, the conductive paste creeping up on one short side end face of the crystal unit 3 forms the conductive bonding member 4 without projecting the conductive paste from the position of the upper main surface of the crystal unit 3. As a result, since the conductive adhesive member 4 does not protrude upward, the possibility of short circuit with the seal ring 25 is reduced, and the crystal oscillator can be formed to be ultra-thin while obtaining desired characteristics. Further, if the ring-shaped ceramic layer 27 is made to protrude toward the inside of the container, it is possible to prevent the conductive resin paste serving as the conductive adhesive member from flowing into the vicinity of the seal ring even when the conductive resin paste rises.

Next, the conductive resin paste is cured by heat treatment, and the container 2 and the quartz oscillator 3 are fixedly joined. Thereafter, the metal lid 6 is placed on the seal ring 25 at the opening of the ceramic package 2 and hermetically sealed by a technique such as seam welding.

A method of forming another embodiment will be described below.

As the steps, only the step of applying the above-mentioned conductive resin paste may be changed.

First, a conductive resin paste is supplied and applied to the electrode pads 22 and 23 in the same manner as described above. However, a small amount may be used as long as it can be securely contacted so that only electrical connection is made. The resin paste is applied to the portion where the conductive resin paste is applied and the ceramic package 2
Is applied so as to cover the inner wall surface on the short side of the crystal oscillator 3 so that the conductive resin paste 4 and the lower surface of the crystal oscillator 3 are in contact with each other. The end face near the extraction electrode of the crystal unit 3 is placed on the insulating resin paste so that the end face can be crawled up. By mounting in this manner, electrical connection can be made with the conductive resin paste on the lower surface of the crystal unit 3, and mechanical connection with sufficient strength can be made with the insulating resin paste. Thereafter, the conductive resin paste and the insulating resin paste may be similarly cured by heat treatment.

FIG. 8 shows still another embodiment. In this embodiment, the ceramic package 2 is connected to the electrode pads 22 and 23.
Is formed of a ring-shaped ceramic layer 2b, and a sealing conductor film 2c is formed on the upper surface of the opening of the ring-shaped ceramic layer 2b. Further, the quartz oscillator 3 is mounted in the same manner as described above as another example, and both the conductive resin paste and the insulating resin paste are hardened by heat treatment, and then bonded to both surfaces or the upper surface of the opening of the ceramic package. By seam welding with a metal lid 6b having a brazing material layer formed on the surface to be formed,
Seal hermetically.

In this case, the electrical connection is made by the conductive adhesive member and the mechanical connection is made by the insulating adhesive member as described above. However, the ceramic package has a structure without a seal ring. And can be made thinner.

In the above-described embodiment, the description has been made of the vibrator using a quartz substrate as the piezoelectric vibrator. However, a vibrator using a piezoelectric ceramic substrate or a single-crystal piezoelectric substrate may be used.

Although the piezoelectric device has been described as a crystal oscillator, it may be an oscillator having only a piezoelectric vibrator or an oscillator having a predetermined circuit such as an IC chip, a capacitor, and a resistor mounted together with the piezoelectric vibrator. .

[0065]

According to the present invention, a cantilever fixing structure in which the piezoelectric vibrator is fixed only at the fixed end thereof can be easily achieved, and a stable vibration space can be secured between the substrate and the quartz vibrator. . In addition, the bonding strength between the piezoelectric vibrator and the substrate can be improved because the piezoelectric vibrator is bonded to both the short side end surface and the lower surface of the piezoelectric vibrator by a simple fixing structure. Further, since the bonding is performed using the side wall of the container, the area in the planar direction can be reduced, and the size can be reduced.

The electrical connection is made by a conductive adhesive member, and the mechanical connection between the piezoelectric vibrator and the container is made by an insulating adhesive member to separate the functions of the electrical connection and the mechanical connection. It is possible to effectively prevent an electrical short circuit around the outside of the piezoelectric vibrator in which a short circuit between electrode pads or another internal wiring is likely to occur.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a crystal oscillator that is a piezoelectric device of the present invention.

FIG. 2 is a top view of a quartz oscillator, which is a piezoelectric device of the present invention, in a state where a lid is omitted.

FIG. 3 is a top view showing the relationship between the crystal unit of the present invention and a conductive adhesive member.

FIGS. 4A to 4C are schematic views showing the operation of the ring-shaped ceramic layer of the present invention.

FIG. 5 is a sectional view of a crystal oscillator which is a piezoelectric device according to another example of the present invention.

FIG. 6 is an enlarged view of a main part of a fixed end portion of a crystal oscillator which is a piezoelectric device according to another example of the present invention.

FIG. 7 is a top view of a crystal oscillator which is another example of the present invention, which is a piezoelectric device, with a lid omitted.

FIG. 8 is a cross-sectional view of a crystal oscillator which is a piezoelectric device as still another example of the present invention.

FIG. 9 is a sectional view of a conventional crystal oscillator.

FIG. 10 is a top view of a conventional crystal oscillator in a state where a lid is omitted.

FIG. 11 is a top view showing a bonding state between a conventional crystal unit and a conductive bonding member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Crystal oscillator 2 ... Container 20 ... Cavity part 21 ... Substrate 22, 23 ... Electrode pad 24 ... Sealing conductor film 25, 25 ... Seal ring 26 ..External terminal electrodes 27 ... Ring-shaped ceramic layer 27a ... Inner wall surface of ring-shaped ceramic layer 3 ... Crystal oscillator 30 ... Crystal substrate 31,33 ... Exciting electrodes 32,34 ... -Lead electrode 4-Conductive adhesive member 5-Bump 5, 5b, 5c-Bump 6-Metal cover

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hideki Ehara 1166, Haseno, Hachimizo-cho, Yokaichi City, Shiga Prefecture Inside the Kyoka Corporation Shiga Plant Yokaichi Block (72) Inventor Hirohisa Takahata 1166, Hanazocho, Hachimicho, Yokaichi City, Shiga Prefecture No. 6 Kyocera Corporation Shiga Plant Yokaichi Block F term (reference) 5J108 BB02 CC04 DD02 EE03 EE04 EE07 EE18 FF01 FF07 GG03 GG11 GG15 GG16 GG20 GG21 KK03

Claims (2)

[Claims] An excitation electrode is formed on both main surfaces of a rectangular piezoelectric substrate, and connected to the excitation electrode on a lower surface on one short side,
A piezoelectric vibrator formed with a pair of extraction electrodes separated in the width direction, and a container having a rectangular cavity, and a pair of electrode pads provided on one short side of the bottom surface of the cavity. A piezoelectric device in which a piezoelectric vibrator is accommodated in the piezoelectric vibrator and a pair of extraction electrodes of the piezoelectric vibrator and the pair of electrode pads are connected via a conductive adhesive member. Near the excitation electrode,
A bump extending in the width direction of the piezoelectric vibrator is formed, and the conductive adhesive member is disposed between the bump and an inner wall surface on one short side of a cavity provided in the container. Piezo device. 2. Exciting electrodes are formed on both main surfaces of a rectangular piezoelectric substrate, and connected to the exciting electrodes on the lower surface on one short side,
A piezoelectric vibrator formed with a pair of extraction electrodes separated in the width direction, and a container having a rectangular cavity, and a pair of electrode pads provided on one short side of the bottom surface of the cavity. A piezoelectric device in which a piezoelectric vibrator is accommodated in the piezoelectric vibrator and a pair of extraction electrodes of the piezoelectric vibrator and the pair of electrode pads are connected via a conductive adhesive member. Near the excitation electrode,
A bump extending in the width direction of the piezoelectric vibrator is formed, and the conductive adhesive member is disposed between the bump and one short side of the piezoelectric vibrator between the upper surface of the electrode pad and the piezoelectric vibrator. A piezoelectric device, wherein an insulating adhesive member is disposed between the conductive adhesive member and an inner wall surface on one short side of a cavity provided in the container.