JP2002100950A - Piezoelectric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric device capable of preventing flow-out and contamination of a low molecular component of a conductive adhesive member to excitation electrodes of piezoelectric element, when the element is housed in a cavity of a container and the electrodes are connected fixedly, and stably conducting proper high-frequency oscillations. SOLUTION: The piezoelectric device comprises a piezoelectric vibrator 3, having the excitation electrodes 31 and 33 formed on both main surfaces of a rectangular piezoelectric substrate 30 and connected to at least a lower side main surface of one short side and a pair of drawing electrodes 32 and 34 isolated in the width direction, and the container 2, having a substantially rectangular cavity 20 and a pair of electrodes pads 23 and 23 provided at one short side in the bottom of the cavity 20. In this case, the vibrator 3 is housed in the cavity 20 of the container 2, and the vibrator 3 is connected to the pads 23 and 23 of the container 2, via only a conductive adhesive member 4 by the electrodes 32 and 34 formed on its lower side main surface.

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 accommodated in a cavity of a container, and more particularly to a piezoelectric device suitable for high-frequency oscillation using overtone. Here, the piezoelectric vibrator includes a vibrator using a quartz plate, a piezoelectric ceramic substrate, or a single crystal piezoelectric substrate.

[0002]

2. Description of the Related Art A crystal oscillator, which is an example of a conventional piezoelectric device, has, for example, a structure shown in FIGS.

The crystal oscillator 51 mainly includes a ceramic package 52, a crystal oscillator 3, and a conductive adhesive member 54.

As shown in FIGS. 7 and 8, the ceramic package 52 has a substrate 521 on which the crystal unit 3 is mounted.
Electrode pads 523 and 523 are formed so as to face. The connection support bumps 55 are formed substantially at the centers of the electrode pads 523 and 523.

The electrode pad 5 on which the bump 55 is formed
After applying a conductive resin paste before the conductive adhesive member 54 is cured on the reference numerals 23 and 523, and disposing the crystal unit 3 such that the fixed end side is placed on the connection support bump 55,
By hardening the conductive resin paste, the quartz oscillator 3 is electrically connected to the substrate 521 and mechanically joined.

The ceramic package 52 is formed by laminating ceramic insulating plates of alumina or the like, and has a cavity 520 for accommodating the crystal resonator 3 therein. The substrate serving as the bottom surface of the cavity 520 is
The substrate 521 on which the crystal resonator 3 is mounted is provided.

External terminal electrodes 526 connected to the electrode pads 523 and 523 are formed on the lower surface of the ceramic package 52, as shown in FIG. further,
Around the opening of the cavity 520 of the ceramic package 52, a seal ring 525 for connecting the metal lid 56 by seam welding is provided. Then, after the crystal oscillator 3 is accommodated and arranged in the cavity 520, while measuring the oscillation frequency of the crystal oscillator 3, Ag or the like is attached to the excitation electrode 33 formed of Au or Ag by vapor deposition, or an ion gun is used. After passing through a step of adjusting the oscillation frequency by increasing or decreasing the mass of the excitation electrode 33 by using a method in which an inert gas such as Ar is struck against the excitation electrode 33 and shaving the surface of the excitation electrode 33, the quartz oscillator 3 is removed. A metal lid 56 is attached on the ceramic package 52 for hermetic sealing.

[0008] More specifically, the quartz oscillator 3 is provided with the structure shown in FIG.
As shown in (a), excitation electrodes 31 and 33 are attached to both main surfaces of a rectangular quartz substrate 30, and the excitation electrodes 31 and 33 are disposed on one short side of the quartz substrate 30. Extending extraction electrodes 32 and 34 are attached. Also,
Each electrode on the front and back of the crystal unit 3 is formed so as to be symmetrical, and the extraction electrode 34 is an electrode 34 a extending from the excitation electrode 33 on the upper surface of the crystal substrate 30 as shown in FIG. , 34b are formed so as to be electrically connected to the lower electrode 34d via the side electrode 34c. Further, as shown in FIG. 10C, the extraction electrode 32 includes electrodes 32 a and 3 extending from the excitation electrode 31 on the lower surface of the quartz substrate 30.
2b is formed so as to be electrically connected to the upper electrode 32d via the side electrode 32c. One short side of the crystal substrate 30 is called a fixed end, and the other short side is called a free end.

In the above-described conventional crystal unit 3, a conductive resin paste which cures to become the conductive bonding member 54 is applied on the electrode pads 523 and 523, and the lower surface of the crystal unit 3 is pulled out above the electrode pads 523 and 523. The crystal oscillator 3 is placed so that the electrodes 32b and 34d are in contact with each other, and a conductive resin paste is poured into the upper portion of the bump 55 so that the crystal oscillator 3
A conductive resin paste is also attached to both short side end faces of the crystal resonator and both long side end faces in the vicinity thereof, so that the crystal unit 3 and the electrode pad 52
The adhesion with 3,523 was ensured.

[0010]

However, in the above method, the conductive resin paste rises along both short side end faces of the crystal resonator 3 and the long side end faces in the vicinity thereof, and the quartz crystal 3 The low molecular weight component 3 contained in the conductive resin paste before the conductive resin paste is hardened until it comes to or near the upper main surface of the substrate 30 and hardens.
9 flows out from the extraction electrodes 34a and 34b on the upper surface side of the crystal unit 3 to the excitation electrode 33 as shown in FIG. 9, and then, in the step of drying the conductive resin paste, the low molecular component 35 is also excited. There is a problem that it sticks on the electrode 33.

As described above, the low molecular weight component 35 is
In the state of being fixed on the upper side, in the subsequent frequency adjustment step, an inert gas such as Ar gas is struck against the excitation electrode 33 by using an ion gun or the like, thereby reducing the mass of the excitation electrode 33 and adjusting the oscillation frequency. At this time, the excitation electrode 3
The region S1 where the low-molecular component 35 is fixed on the three surfaces is the A of the excitation electrode 33 where the fixed low-molecular component 35 reduces the mass.
This prevents the removal of u and Ag. As a result, the fixed low-molecular component 35 is also transferred to the extraction electrode 34 a on the excitation electrode 33.
As a result, only the excitation electrode 33 in the other region S2 is scraped off, and the method of reducing the mass of the entire excitation electrode 33 is biased.

As described above, when the crystal resonator 3 in which the surface of the excitation electrode 33 is biased and the surface of the excitation electrode 33 is cut off is used as the oscillator, the oscillation is performed using the fundamental wave as in the conventional case.
It has been confirmed that the relatively low frequency oscillator used in the MHz frequency band has little effect on the electrical characteristics. However, using an overtone oscillation such as a third harmonic, an oscillator with a higher frequency of 100 MHz or more is used. When used as, the good confinement of vibration not only generates unnecessary spurious, but also deteriorates overtone oscillation such as main vibration and third harmonic, and increases the crystal impedance value which is the resonance resistance. In some cases, problems such as oscillation stop may occur.

The present invention solves the above-mentioned problems of the prior art, in which a piezoelectric vibrator is accommodated in a cavity of a container, and an excitation electrode of the piezoelectric vibrator and an electrode pad of the container are electrically conductively bonded. When connecting and fixing via the via, the low molecular component of the conductive resin paste before hardening flows out to the excitation electrode surface on the upper side of the piezoelectric vibrator and can be prevented from sticking to the excitation electrode, which is stable and good. It is an object of the present invention to provide a piezoelectric device capable of performing high-frequency oscillation.

[0014]

According to the piezoelectric device of the present invention, excitation electrodes are formed on both main surfaces of a substantially rectangular piezoelectric substrate,
A piezoelectric vibrator formed from a pair of lead-out electrodes derived from each of the excitation electrodes on at least a lower main surface on one short side of the piezoelectric substrate and separated in a width direction of the piezoelectric substrate; A container having a cavity and a pair of electrode pads provided on one short side of a bottom surface of the cavity, wherein the piezoelectric vibrator is housed in a cavity of the container, In a piezoelectric device in which a lead electrode and an electrode pad of the container are connected via a conductive adhesive member, the piezoelectric vibrator is connected only by the lead electrode formed on a lower main surface thereof. It consists of a configuration.

According to this configuration, in the manufacturing process, a conductive resin paste is applied on the electrode pads of the container body, and the piezoelectric electrodes are formed on the upper portions thereof so that the extraction electrodes formed on the lower surface of the piezoelectric vibrator are connected to the electrode pads. By mounting the vibrator and heating and curing the conductive resin paste, only the extraction electrode formed on the lower surface of the piezoelectric vibrator is connected to the electrode pad of the container via the conductive resin paste, and Since the vibrator is fixed to the container body, the conductive adhesive before curing is not attached to the upper surface or side surface of the piezoelectric vibrator, thereby reducing the conductive resin paste on the excitation electrode on the upper surface of the piezoelectric vibrator. The molecular components do not flow out.

In this way, in the frequency adjustment step, the excitation electrode has electrical characteristics, such as the crystal impedance value of the crystal oscillator, generated due to the low molecular weight component of the conductive resin paste being fixed to the excitation electrode. Can be prevented from decreasing. As a result, it is possible to perform stable and good high-frequency oscillation using the overtone.

Preferably, the area of the electrode pad is twice or more as large as the area of the bonding portion where the conductive bonding member is bonded to the electrode pad.

According to this configuration, the piezoelectric vibrator is connected to the lead electrode formed on the lower surface of the piezoelectric vibrator on the uncured conductive resin paste applied on the electrode pad of the container in the manufacturing process. When the is mounted, the adhesive portion of the conductive resin paste is pushed out. However, since the area of the electrode pad of the container body is at least twice as large as the area of the adhesive portion of the electrode pad, the conductivity before curing is increased. The resin paste spreads only in the region on the electrode pad without protruding to the top and side surfaces of the piezoelectric vibrator, and the conductive paste is applied along both short side end surfaces of the crystal oscillator and long side ends in the vicinity thereof. As a result, it becomes difficult to ascend, and the above-described operation and effect can be further ensured.

[0019]

Embodiments of the present invention will be specifically described below with reference to the drawings. The piezoelectric device for high-frequency oscillation using overtone oscillation described here is used, for example, in a crystal oscillator using a crystal oscillator.

(First Embodiment) FIGS. 1 to 3 show a configuration example of a piezoelectric device 1 according to a first embodiment of the present invention. Here, FIG. 1 is a top view showing the piezoelectric device 1 with the lid omitted, and FIG. 2 is a sectional view thereof.

The piezoelectric device 1 mainly includes a ceramic package 2 which is a container having a substrate 21, a quartz oscillator 3, a conductive adhesive member 4, and a lid 6.

The ceramic package 2 comprises a substantially rectangular single-plate ceramic substrate 21, a ring-shaped substrate 22 laminated around the ceramic substrate 21, and a seal ring 25 mounted on the surface thereof. . The seal ring 25 is brazed and fixed via the conductor film 24 for sealing. And this ceramic package 2
A substantially rectangular cavity portion 20 having an upper opening is formed, and the crystal resonator 3 is accommodated therein. Further, a pair of substantially rectangular electrode pads 23 are formed on the bottom surface of the cavity 20, that is, on one short side of the upper surface of the substrate 21 so as to be arranged in the width direction of the short side of the container 2. I have.

More specifically, the seal ring 25 is made of Fe
-Ni, Fe-Ni-Co, etc.
A ring-shaped substrate 22 is laminated around the substrate 1 and is formed by brazing or the like on a sealing conductor film 24 formed on the surface thereof, thereby defining the thickness of the cavity portion 20.

On the bottom surface of the ceramic package 2, there are formed external terminal electrodes 26 which are electrically connected to the electrode pads 23 and 23 and are connected to an external printed wiring board (not shown). The electrode pads 23 and the external terminal electrodes 26 are connected to each other by via-hole conductors penetrating a part of the ceramic package 2. In the case where the electrode pads 23 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 20, the connection can be easily made by the via hole conductor. Further, the substrate 21 is, for example, 2
It is also possible to adopt a configuration in which the internal wiring is formed by laminating layers, and one end of the internal wiring is connected to the electrode pads 23 and 23 via the via-hole conductor, and the other end of the internal wiring is connected to the external wiring. Connected to terminal electrode 26.

The surfaces of the electrode pads 23, 23
A band-shaped bump 4a is formed near the center of the cavity portion 20, and a bump 4b parallel to the band-shaped bump 4a is formed separately. The bumps 4a and 4b are formed by baking a conductive metal paste, printing and curing a conductive resin paste. Here, the band-shaped bumps 4a and 4b are
Although an example in which the electrode pads 23 are formed over the entire width in the width direction has been described, the shape of the bumps may be appropriately changed, and may be formed in a dot shape, for example.

The electrode pad 23, the sealing conductor film 24, and the bumps 4a and 4b are made of a metal such as molybdenum or tungsten. These conductors (electrode pads 23, conductor films 24, and bump members 4a and 4b) are formed by baking a conductive resin paste on the surface of the substrate 21 and then performing Ni and Au plating on the surface. You.

For example, when the bumps 4a and 4b are formed by baking a conductive metal paste, the electrode pads 2
The conductors serving as the base conductors 3 and 23 are printed and formed with a conductive metal paste, and after drying, the surface thereof is printed and formed with a conductive metal paste according to the shapes of the bumps 4a and 4b. They are formed by firing both.

These conductors (electrode pad 23, conductor film 2
4. The thickness of the bumps 4a, 4b) is about 10 μm to 30 μm.
m so that the bump 4
The height up to the apex of a, 4b is 20 μm to 40 μm.

As described above with reference to FIG. 10, for example, the quartz oscillator 3 has excitation electrodes 31 on both main surfaces of a substantially rectangular quartz substrate 30 cut (AT cut) according to a predetermined crystal azimuth. , 33, and extraction electrodes 32, 34 extending from the pair of excitation electrodes 31, 33 in the short side direction of the quartz substrate 30, respectively.

More specifically, the respective electrodes on the front and back sides of the crystal unit 3 are formed so as to be symmetrical.
As shown in FIG. 10C, the electrodes 32a and 32b extending from the excitation electrodes 31 on the lower surface of the quartz substrate 30 are formed so as to be electrically connected to the electrodes 32d on the upper surface via the side electrodes 32c. Further, the extraction electrode 34 is the same as that shown in FIG.
As shown in (b), the excitation electrode 3 on the upper surface of the quartz substrate 30
The electrodes 34a, 34b extending from the third electrode 3 are formed so as to be electrically connected to the lower electrode 34d via the side electrode 34c. The shapes of the extraction electrodes 32 and 34 correspond to the electrode pads 23 and 23 when the crystal resonator 3 is arranged at a predetermined position.

The excitation electrodes 31, 33 and the extraction electrodes 32, 34 are provided on the upper and lower surfaces of the quartz substrate 30,
It is formed by depositing a mask of a predetermined shape and depositing Au, Ag, Cr, or the like using means such as evaporation or sputtering.

The electrical connection and mechanical bonding between the ceramic package 2 and the crystal unit 3 are performed by hardening a conductive resin paste obtained by adding Ag powder or the like to a resin such as a silicon-based, epoxy-based, or polyimide-based resin. The bonding is performed by a conductive bonding member 4 to be bonded.

Specifically, the electrode pads 2 on the surface of the substrate 21
A conductive resin paste is supplied onto the electrode pads 23 and 23 by a dispenser or the like, and the conductive resin paste is extended on the electrode pads 23 and 23 to the lower surface on one short side of the crystal resonator 3. The quartz oscillator 3 is placed so that the extracted lead electrodes 32 and 34 are in contact with each other, and the conductive resin paste is cured. As a result, the pair of excitation electrodes 31 and 33 of the crystal resonator 3 are electrically connected to the external terminal electrodes 26 on the outer surface of the ceramic package 2 via the electrode pads 23 and 23.

The metal lid 6 is made of a flat metal, for example, F
It is made of e-Ni alloy (42 alloy), F-Ni-Co alloy (Kovar), or the like. Such a metal lid 6 hermetically seals the cavity 20 in which the crystal resonator 3 is housed with nitrogen gas, vacuum, or the like. Specifically, the metal lid 6 is placed on the seal ring 25 of the ceramic package 2 in a predetermined atmosphere, and the metal on the surface of the seal ring 25 and a part of the metal of the metal lid 6 are welded. A predetermined current is applied to perform seam welding. In order to perform this welding reliably, an Ag brazing layer or the like may be formed in advance on the joining surface side of the metal lid 6. In addition, the metal lid 6 is melted by welding so that the brazing material contributing to joining does not decrease due to the surface of the metal lid 6 being reduced.
A Ni plating layer may be formed on the surface side of.

The above-described piezoelectric device 1 is manufactured through the following manufacturing steps.

First, a substantially rectangular crystal substrate 30 is prepared. Next, the excitation electrodes 31 and 33 are provided on both main surfaces of the quartz substrate 30.
Are formed, and the extraction electrodes 32 and 34 are formed to obtain the crystal resonator 3. In addition, a pair of electrode pads 23, 23 is formed on the surface of a substrate 21 serving as the bottom surface of the ceramic package 2, and a sealing conductor film 24 and a seal ring 25 are formed on the surface around the opening of the cavity 20. A package 2 and a metal lid 6 are prepared.

Next, a conductive resin paste which becomes the conductive adhesive member 4 by being cured on the electrode pads 23 is supplied and applied by a dispenser or the like. At this time, the supplied conductive resin paste has a substantially hemispherical shape in which the whole is raised.

Next, the quartz oscillator 3 is placed on a conductive resin paste having a substantially hemispherically raised shape. Specifically, a pair of extraction electrodes 32 and 34 abut on a portion to which the conductive resin paste is supplied, and the quartz crystal vibrating so that the application region of the conductive resin paste is completely covered by the extraction electrodes 32 and 34. The child 3 is placed.

Next, the conductive resin paste is heated and cured, and the ceramic package 2 and the quartz oscillator 3 are fixedly joined.

Next, the oscillation frequency of the quartz oscillator 3 is measured using the external terminal electrodes 26 and the like. If necessary, the surface of the upper excitation electrode 31 of the quartz oscillator 3 is irradiated with Ar or the like using an ion gun or the like. The inert gas is applied to the excitation electrode 31 to cut the excitation electrode 31 and reduce the mass of the excitation electrode 31, thereby adjusting the frequency.

Thereafter, in a predetermined atmosphere, the metal lid 6 is placed on the seal ring 25 of the ceramic package 2 to which the crystal oscillator 3 is bonded and fixed, and both are sealed by seam welding. Thus, the piezoelectric device 1 is completed.

In the above-described piezoelectric device 1, as shown in FIG. 1, a conductive resin paste is applied in advance to the inside of the quartz oscillator 3 so as to cover the bumps 4a, and the lower surface of the quartz oscillator 3 is The lead-out electrodes 32 and 34 are in contact with each other, and the quartz-crystal vibrating device 3 is so set that the lead-out electrodes 32 and 34 completely cover the application region of the conductive resin paste.
Is placed.

Thus, it is possible to prevent low-molecular components contained in the conductive resin paste from flowing out from the extraction electrode 32 to the excitation electrode 31 on the upper surface of the crystal resonator 3 until the conductive adhesive member 4 is hardened. As a result, in the subsequent frequency adjustment step, by injecting an inert gas such as Ar, shaving the excitation electrode 31 and reducing the mass, when adjusting the frequency, the low molecular components do not flow into the excitation electrode 31. Therefore, the entire excitation electrode 31 is uniformly shaved, so that the deterioration of the crystal impedance value can be prevented.

The quartz oscillator 3 according to the present invention having a frequency of 106.25 MHz (third harmonic) and a length of 3.5 mm and a width of 2.0 mm has electrical characteristics such as CI value and drop resistance. Although reliability was confirmed, results equivalent to or higher than those of the related art were obtained without deteriorating both electrical characteristics and strength.

(Second Embodiment) FIGS. 4 and 5 show a configuration example of a piezoelectric device 1 'according to a second embodiment of the present invention. Here, FIG. 4 is a top view showing the piezoelectric device 1 'with the lid omitted, and FIG. 5 is a top view showing the ceramic package 2'.

This ceramic package 2 'has the structure shown in FIG.
As shown in FIG. 7, a dot-shaped bump 4d is formed at substantially the center of each electrode pad 23. Furthermore, a band-shaped bump 4
b is formed on the outer edge over the entire width in the width direction on each electrode pad 23, and a band-shaped bump 4 e is formed on the outer edge along the longitudinal direction on each electrode pad 23, and both bumps 4 b , 4e are L-shaped in plan view.

Then, the quartz oscillator 3 is connected to each electrode pad 23 of the ceramic package 2 only by the lead electrode 32 on the lower surface by using a small amount of conductive resin paste at the dot-shaped bump 4d. At this time, the bumps 4b and 4e prevent the conductive resin paste from flowing from the lower surface of the crystal unit 3 to the end surface or the upper surface and adhering to the end surface or the upper surface of the crystal unit 3. Like that.

In each of the above-described embodiments, it has been confirmed by experiments that the area of the electrode pad 23 should be at least twice as large as the area of the bonding portion of the conductive bonding member 4.

Specifically, for example, as shown in FIG.
Assuming that the diameter of the conductive resin paste applied on the electrode pad 23 is φ0.7 mm, the conductive resin paste spreads with a radius R1.5 mm and reaches the boundary line indicated by L1.

Therefore, the lead electrodes 32 and 34 formed on the lower surface of the crystal unit 3 are positioned on the uncured conductive adhesive member 4 applied on the electrode pads 23 of the ceramic package 2 in the manufacturing process. When the quartz oscillator 3 is mounted on the ceramic package 2, the bonding portion of the conductive bonding member 4 is pushed out. However, since the area of the electrode pad 23 of the ceramic package 2 is twice or more the area of the bonding portion, The conductive adhesive member 4 before curing does not protrude to the upper surface or side surface of the crystal resonator 3 but spreads only in the region on the electrode pad 23.

For this reason, the conductive resin paste is heated and cured, and only the lead electrodes 32 and 34 formed on the lower surface of the crystal unit 3 are applied to the electrode pads 23 of the ceramic package 2 via the conductive adhesive member 4. Since the crystal resonator 3 is connected and fixed to the ceramic package 2, it is possible to prevent the low molecular components of the conductive adhesive member 4 from flowing out to the excitation electrode 31 on the upper surface of the crystal resonator 3. .

As a result, the electrical characteristics such as the CI value of the crystal oscillator 3 generated in the frequency adjustment step due to the excitation electrode 31 being fixed by the low molecular component of the conductive resin paste are reduced. Therefore, if this piezoelectric device 1 is used, stable and good high-frequency oscillation using overtones can be performed.

As described above, the piezoelectric device of the present invention is not limited to the specific configuration of each of the above-described embodiments, and it is needless to say that the configuration may be modified, added, or deleted as needed.

For example, in the above, 106.25 for the third harmonic.
Although described using the example of the piezoelectric device using the crystal oscillator of MHz, the present invention is not limited to this, and any piezoelectric device using a high-frequency piezoelectric oscillator of 100 MHz or more using overtones. The present invention can be similarly applied. For example, 100MHz
At frequencies other than the above 106.25 MHz, 5th harmonic and 7
The present invention can also be applied to a piezoelectric device using a high-frequency piezoelectric vibrator using a higher-order overtone such as a harmonic.

Further, the quartz oscillator 3 shown in FIG.
In the above, the configuration example in which the extraction electrode 32 derived from the excitation electrode 31 on the lower surface is connected to the electrode 32d on the upper surface has been described. This indicates that the present invention can be applied to the crystal resonator 3 conventionally used. However, the piezoelectric vibrator used in the piezoelectric device of the present invention is not limited to the shape of the crystal vibrator 3 shown in FIG.

That is, in the present invention, the piezoelectric vibrator is configured to be connected to the electrode pad of the container via only the lead electrode formed on the lower surface of the piezoelectric vibrator via the conductive adhesive member. The extraction electrode may be formed on the lower surface. For example, an electrode derived from the excitation electrode on the upper surface of the piezoelectric vibrator is connected to a lead electrode formed on the lower surface of the piezoelectric vibrator via the side surface of the piezoelectric vibrator, and is derived from the excitation electrode on the lower surface. The lead electrode may be formed only on the lower surface.

[0057]

As described above, the piezoelectric device of the present invention has a configuration in which the piezoelectric vibrator is connected only by the extraction electrode formed on the lower main surface thereof. A conductive resin paste is applied on the electrode pad of the body, and a piezoelectric vibrator is mounted thereon such that a lead electrode formed on a lower surface of the piezoelectric vibrator is connected to the electrode pad, and the conductive resin paste is heated and cured. By doing so, only the extraction electrode formed on the lower surface of the piezoelectric vibrator is connected to the electrode pad of the container via the conductive resin paste, and the piezoelectric vibrator is fixed to the container. Because the conductive adhesive member is not attached to the upper surface or side surface of the piezoelectric vibrator, the low molecular weight component of the conductive resin paste does not flow out to the excitation electrode on the upper surface of the piezoelectric vibrator. That.

As a result, in the frequency adjusting step, the excitation electrode is caused to adhere to the low molecular weight component of the conductive resin paste, and the electrical characteristics such as the crystal impedance value of the crystal oscillator generated due to the adhesion of the excitation electrode to the excitation electrode. Can be prevented from decreasing. As a result, stable and good high-frequency oscillation using the overtone can be performed.

Preferably, the area of the electrode pad is set to be at least twice as large as the area of the bonding portion where the conductive bonding member is bonded to the electrode pad.

According to this configuration, the piezoelectric vibrator is connected to the lead electrode formed on the lower surface of the piezoelectric vibrator on the uncured conductive resin paste applied on the electrode pad of the container in the manufacturing process. When the is mounted, the adhesive portion of the conductive resin paste is pushed out. However, since the area of the electrode pad of the container body is at least twice as large as the area of the adhesive portion of the electrode pad, the conductivity before curing is increased. The resin paste spreads only in the region on the electrode pad without protruding to the top and side surfaces of the piezoelectric vibrator, and the conductive paste is applied along both short side end surfaces of the crystal oscillator and long side ends in the vicinity thereof. As a result, it becomes difficult to ascend, and the above-described function and effect can be further ensured. In addition, a highly reliable piezoelectric device can be efficiently produced.

[Brief description of the drawings]

FIG. 1 is a top view illustrating a configuration example of a piezoelectric device according to a first embodiment of the present invention with a lid omitted.

FIG. 2 is a cross-sectional view illustrating a configuration example of the piezoelectric device according to the first embodiment of the present invention.

FIG. 3 is a top view showing a ceramic package used for the piezoelectric device according to the first embodiment of the present invention.

FIG. 4 is a top view illustrating a configuration example of a piezoelectric device according to a second embodiment of the present invention with a lid.

FIG. 5 is a top view showing a ceramic package used for a piezoelectric device according to a second embodiment of the present invention.

FIG. 6 is an explanatory diagram for explaining characteristics of a conductive adhesive member applied on an electrode pad of a container body in the piezoelectric device of the present invention.

FIG. 7 is a top view illustrating a configuration example of a conventional piezoelectric device without a lid.

FIG. 8 is a cross-sectional view illustrating a configuration example of a conventional piezoelectric device.

FIG. 9 is a top view illustrating a state in which a low molecular component of a conductive adhesive member is attached to an excitation electrode of a quartz oscillator in a conventional piezoelectric device, with a lid omitted.

10A and 10B are diagrams illustrating a configuration example of a crystal resonator used for a piezoelectric device, where FIG. 10A is a perspective view, FIG. 10B is a top view, and FIG. 10C is a bottom view.

[Explanation of symbols]

 1, 1 'piezoelectric device 2, 2' ceramic package (container) 3 crystal oscillator (piezoelectric oscillator) 4 conductive adhesive member 20 cavity 23 electrode pad 30 piezoelectric substrate 31, 33 excitation electrode 32, 34 extraction electrode

Claims (2)

[Claims] An excitation electrode is formed on both main surfaces of a substantially rectangular piezoelectric substrate, and at least a lower main surface on one short side of the piezoelectric substrate is led out from each excitation electrode on the lower main surface, and the piezoelectric substrate A piezoelectric vibrator formed with a pair of extraction electrodes separated in the width direction, and a container body having a substantially rectangular cavity, and having a pair of electrode pads on one short side on the bottom surface of the cavity, A piezoelectric device in which the piezoelectric vibrator is housed in a cavity of the container, and a lead electrode of the piezoelectric substrate and an electrode pad of the container are connected via a conductive adhesive member; A vibrator is connected only by the lead electrode formed on the lower main surface thereof. 2. An area of the electrode pad is 2 times an area of an adhesion portion where the conductive adhesive member adheres to the electrode pad.
2. The piezoelectric device according to claim 1, wherein the size of the piezoelectric device is twice or more.