JP2001077656A - Piezoelectric device and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain superior oscillation by connecting lead-out electrodes and electrode pads of a piezoelectric vibrator via a conductive adhesion member and arranging the conductive adhesion member over the reverse surface, short- side end surface, and long-side end surface of the piezoelectric vibrator. SOLUTION: A conductive adhesion member 4 is interposed between lead-out electrodes 32 and 34 on the reverse surface of a crystal oscillator 3 and electrode pads 22 and 23 on the top surface of a substrate 21 of a ceramic package by a thickness corresponding to, e.g. the height of a bump and also arranged over the end surface part of one short side and the end surface of long sides of the crystal vibrator 3. The conductive adhesion member 4 is stuck on only the reverse surface and end surface of the crystal vibrator 3 and is not substantially stuck on the top surface side. Namely, conductive resin paste forming the conductive adhesion member does not spread from the lead-out electrode 32 to an exciting electrode 31. Since no unwanted sticking matter is present on the top surface, vibration in oscillation characteristics of the crystal vibrator 3 can be suppressed effectively.

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 bonded to a substrate of a container or the like via a conductive adhesive member obtained by curing a conductive resin paste and a method of manufacturing the same. Note that the piezoelectric vibrator includes a vibrator using a quartz plate, a piezoelectric ceramic substrate, and a single crystal piezoelectric substrate, and a piezoelectric device includes an oscillator having only a piezoelectric vibrator alone and an IC together with the piezoelectric vibrator. An oscillator equipped with a predetermined circuit such as a chip, a capacitor, and a resistor. The substrate is an insulating substrate having a flat plate shape as a whole, a housing-like ceramic package having electrode pads in a flat plate portion, or the like.

[0002]

2. Description of the Related Art As shown in FIGS. 8 to 10, a conventional piezoelectric device, for example, a crystal oscillator, includes a crystal oscillator, which is a piezoelectric oscillator, in a ceramic package having a fixed step portion on which electrode pads are formed. Had been placed.

A quartz oscillator 51 shown in FIGS. 8 and 9 is mainly composed of a ceramic package 52, a quartz oscillator 53, a conductive adhesive member 57, and a lid 60 (see Japanese Patent Application Laid-Open No.
3610).

A ceramic package 52 is formed by laminating a ceramic insulating plate of alumina or the like, and has a quartz oscillator 5 inside.
3 is formed.

Further, external terminal electrodes of the ceramic package 52 are formed, and stepped portions 55 and 56 are formed inside the ceramic package 52 at both ends in the longitudinal direction. One of the step portions 55 is a fixing step portion, the surface of which is formed with a groove 58 so as to be divided into two in the width direction, and the external terminal electrodes 52b and 52c (52c do not appear in the drawing). ) Are formed with electrode pads 55a and 55b. The other step part holds the tip of the crystal unit 53 and is a holding step part 56. The external terminal electrode 52d is a terminal electrode that is at the ground potential.

The quartz oscillator 53 has excitation electrodes 54a, 54c opposed to each other on both main surfaces of a rectangular quartz substrate.
Extraction electrodes 54b and 54d extending from the excitation electrodes 54a and 54c to both main surfaces on one short side of the quartz substrate are formed. Each of these electrodes is formed by means such as vapor deposition.

An oscillator using such a crystal is manufactured through the following manufacturing steps.

First, the above-described crystal unit 53 and the ceramic package 52 having the above-described structure are prepared.

Next, a conductive resin paste to become a conductive adhesive member 57 is applied to the electrode pads 55a and 55b on the surface of the fixing step 55, and the quartz oscillator 53 is placed on the applied conductive resin paste. It is mounted so that the extraction electrodes 54b and 54d are located. Further, the conductive resin paste is applied and supplied again to the end face and the upper surface on one short side of the quartz oscillator 53 so as to be electrically connected to the conductive resin paste located below the quartz oscillator 53. Was.

After that, the conductive resin paste is cured,
In order to fix the ceramic package 52 and the piezoelectric vibrator 53 and to hermetically seal the crystal vibrator 53, a lid 60 is attached on the ceramic package 52.

As another structure, as shown in FIG. 10, grooves 59 are formed at both ends of the fixing step 55 in the short side width direction.
Had formed. That is, two grooves 59 are provided between the inner wall extending in the longitudinal direction of the ceramic package 52 and the fixing step 55.

Thus, even when a large amount of the conductive resin paste to be the conductive adhesive member 57 is applied, excess paste flows into the groove 59 and the amount of the conductive resin paste existing in the fixing step 55 is applied. And the bonding area between the extraction electrodes 54b, 54d on the lower surface side of the crystal unit 53 and the electrode pads 55a, 55b is made uniform. As a result, the variation in shrinkage stress during heat curing is reduced,
Oscillation frequency variation and characteristic variation are kept small (Japanese Patent Laid-Open No. 7-240653).

[0013]

However, in the prior art, a conductive resin paste is applied and supplied to the upper surface of the crystal unit 53. As a result, the conductive resin paste is applied to the excitation electrode 54a on the upper surface side of the crystal unit 53.
In order to spread to the side, the fundamental vibration is damped, and CI
(Crystal impedance) value becomes worse, and damping is seen in oscillation characteristics.

Conversely, if the amount of conductive resin paste to be supplied is reduced in order to eliminate the conductive resin paste applied on the surface of the crystal unit 53, damping of the fundamental wave is suppressed, and the CI value is good. However, the bonding strength between the ceramic package 52 and the crystal unit 53 is reduced. As a result, when the mechanical strength is reduced and an impact is applied from the outside due to a drop or the like, peeling is likely to occur at the joint portion, and the oscillation frequency largely changes or oscillation failure occurs.

The present invention has been made in view of the above problems, and has as its object to suppress the conductive resin paste spreading on the excitation electrode on the surface side of a piezoelectric vibrator, which is a quartz vibrator, and to achieve a good result. An object of the present invention is to provide a piezoelectric device capable of oscillating and having good bonding strength and a method for manufacturing the same.

[0016]

According to the present invention, there is provided a piezoelectric vibrator in which excitation electrodes are formed on both main surfaces of a rectangular piezoelectric substrate, and extraction electrodes connected to the excitation electrodes are formed on the lower surface on one short side. A piezoelectric device, wherein a lead is disposed in a container having a pair of electrode pads formed on a surface of a substrate, so that an extraction electrode of the piezoelectric vibrator and the electrode pad are connected via a conductive adhesive member; The conductive adhesive member is a piezoelectric device, wherein the conductive adhesive member is disposed so as to straddle the lower surface of the piezoelectric vibrator, the short side end surface, and the long side end surface.

A step of preparing a piezoelectric vibrator in which excitation electrodes are formed on both main surfaces of a rectangular piezoelectric substrate, and an extraction electrode connected to the excitation electrode is formed on the lower surface on one short side;
A step of preparing a substrate having a pair of electrode pads formed on the surface thereof, and supplying a conductive resin paste to be a conductive adhesive member to the pair of electrode pads. A step of placing on the paste, a step of curing the conductive resin paste, wherein the corners at both ends of one short side of the piezoelectric vibrator are located at the center of the supplied conductive resin paste. A method of manufacturing a piezoelectric device, wherein the piezoelectric device is mounted at a position outside both the width direction and the longitudinal direction of the piezoelectric device.

[0018]

According to the present invention, an electrode pad is formed on a surface of a substrate which is a part of a ceramic package, and a lead electrode of a piezoelectric vibrator is a conductive adhesive member formed by curing a conductive resin paste. Are electrically and mechanically joined together.

More specifically, the conductive adhesive member is applied to the end faces of the piezoelectric vibrator which are both corners of one short side, that is, the short side end face and the long side end face. Will be.

[0020] Thus, the joining between the ceramic package and the piezoelectric vibrator is made with one short side end face of the piezoelectric vibrator.
This is performed with two long side end surfaces, and the joint is fixed at a total of three end surfaces.

Accordingly, the bonding strength is improved, and when an external impact is applied due to dropping or the like, peeling is less likely to occur at the bonded portion, and the oscillation frequency is greatly changed.
Oscillation failure does not occur.

At the same time, the portions where the conductive adhesive member adheres to the piezoelectric vibrator are the lower surface and the above-mentioned three end surfaces, and the conductive adhesive member does not substantially adhere to the front surface side of the piezoelectric vibrator.

As a result, since the conductive resin paste serving as the conductive adhesive member does not spread on the excitation electrode, no foreign matter adheres to the excitation electrode on the surface side of the piezoelectric vibrator, so that the oscillation characteristics fluctuate. There is no.

According to the second invention, when the piezoelectric vibrating element is mounted on the conductive resin paste supplied to the electrode pad, the corners at both ends of one short side of the piezoelectric vibrator are supplied. The conductive resin paste is placed so that both the short side and the long side of the conductive resin paste are located outside the center (the top of the swell).

Accordingly, although the conductive resin paste exposed from the outer side on both the short side and the long side of the piezoelectric vibrator is reduced, the conductive resin paste may be adhered to the short and long side end faces of the piezoelectric vibrator. it can.

As a result, the conductive resin paste adhered to the end faces on the short side and the long side of the piezoelectric vibrator does not extremely climb on the surface side of the piezoelectric vibrator.

As a result, the above-described piezoelectric device can be achieved reliably and easily.

In the above-mentioned invention, the adhesion of the conductive resin paste (conductive adhesive member) on the front side and the end face side of the piezoelectric vibrator is mentioned. As a structure for controlling the spread of the conductive resin paste, for example, a bump is formed on an electrode pad. This makes it possible to control the thickness of the conductive resin paste that can exist between the substrate surface of the ceramic package and the lower surface of the piezoelectric vibrator, and to prevent the conductive resin paste on the lower surface from spreading to the lower excitation electrodes. . Further, by forming such bumps, it is possible to secure a necessary vibration space between the lower surface of the piezoelectric vibrator other than the electrode pads and the surface of the substrate.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a piezoelectric device according to the present invention and a method for manufacturing the same will be described in detail with reference to the drawings.

In the description, a piezoelectric device using a quartz oscillator as the piezoelectric oscillator, for example, a quartz oscillator will be described.

FIG. 1 is a top view of a quartz oscillator, which is a piezoelectric device according to the present invention, in a state where a lid is omitted, and FIG. 2 is a sectional view thereof. FIG. 3 is a perspective view showing one short side end of the crystal unit.

The crystal oscillator 1 of the piezoelectric device according to the present invention comprises:
It is mainly composed of a container 2 having a substrate 21, a quartz oscillator 3, a conductive adhesive member 4 and a lid 6.

The ceramic package 2, which is a container,
A rectangular single-plate ceramic substrate 21 and a ceramic substrate 2
1 and a seal ring 25 provided around the periphery of the seal ring 1. The seal ring 25 is formed of the sealing conductor film 2.
4 and is fixed by brazing. And, as a whole, it has an opening on the front side as shown in FIG.
A substantially rectangular cavity portion 20 for accommodating the crystal resonator 3 is formed. Further, a pair of electrode pads 22 and 23 for electrically connecting to the crystal oscillator 3 are formed on one short side (the left side in FIG. 1) of the bottom surface of the cavity portion 20, that is, the upper surface of the substrate 21. I have. This electrode pad 2
The reference numerals 2 and 23 are formed separately in the width direction of the short side (the vertical direction in FIG. 1). Its shape is substantially rectangular.

The above-mentioned seal ring 25 is made of Fe—Ni,
It is made of a metal such as Fe-Ni-Co and is formed by brazing or the like on the sealing conductor film 24 formed around the substrate 21, thereby defining the thickness of the cavity portion 20. If the thickness is insufficient, a ring-shaped substrate may be stacked around the substrate 21 and the seal ring 25 may be attached to the surface of the ring-shaped substrate.

An external terminal electrode 26 is formed on the bottom surface of the ceramic package 2 to be electrically connected to the electrode pads 22 and 23 and to be connected to an external printed wiring board. The electrode pads 22 and 23 and the external terminal electrodes 26 are connected by via-hole conductors penetrating a part of the ceramic package 2. Electrode pad 22,
If the position of the external terminal electrode 26 does not correspond to the position of the external terminal electrode 26, a wiring conductor having a predetermined shape may be formed on the bottom surface of the cavity portion 22 so that the connection can be easily performed by the via-hole conductor. Further, the substrate 21 itself may be laminated in a two-layer structure, for example, and an internal wiring may be formed therebetween.
One end of the internal wiring is connected to an electrode pad via a via-hole conductor, and the other end of the internal wiring is connected to an external terminal electrode.

The bumps 5 are formed on the surfaces of the electrode pads 22 and 23, especially near the center of the cavity 20. The bumps 5 are formed by baking a conductive metal paste, printing and curing a conductive resin paste or an insulating resin paste, and, for example, form a band over the entire width of one of the electrode pads 22 and 23 in the width direction. It may be formed or may be formed in a dot shape.

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 bump members 5) are formed by baking a conductive resin paste on the surface of the substrate 21 and then plating the surface with Ni and Au.

For example, when the bumps 5 are formed by baking a conductive metal paste, a conductor serving as a base conductor for the electrode pads 22 and 23 is printed and formed with the above-mentioned metal paste, and after drying, the above-mentioned metal is formed on the surface. It is formed by printing using a paste in accordance with the shape of the bump 5 and then performing a baking process on both.

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

The crystal unit 3 as a piezoelectric unit is, for example, a rectangular crystal substrate 30 cut (AT cut) according to a predetermined crystal azimuth angle, and an excitation formed on both main surfaces of the crystal substrate 30. Electrodes 31, 33 and a pair of excitation electrodes 3
Extraction electrodes 32 and 34 extend from the reference numerals 1 and 33 in the short side direction (left side in the figure) of the quartz substrate 30, respectively. For example, the extraction electrode 32 extending from the upper surface side excitation electrode 31 extends near the short side of the upper surface, and extends through one long side end surface (lower end surface in the drawing) near the short side. Has been extended to. Conversely, the excitation electrode 33 on the lower surface side
The extraction electrode 34 extending from the lower surface extends near the short side of the lower surface, and extends to the upper surface side via the other long side end surface (the upper end surface in the drawing) near the short side. That is,
The extraction electrodes 32 and 34 are not formed on one short side end face of the quartz substrate 30 but are formed on the long side end face that is in contact with the one short side. The extraction electrodes 32 and 34 are formed at positions opposing each other on both main surfaces of the quartz substrate 30, and have a shape that can be electrically connected to the electrode pads 22 and 23 when arranged at a predetermined position. .

The excitation electrodes 31 and 33 and the extraction electrodes 32 and 34 are formed on a top surface and a bottom surface of the quartz substrate 30 by using a mask having a predetermined shape, and using a means such as vapor deposition or sputtering. It is formed by vapor deposition of Cr or the like.

The above-described electrical connection and mechanical connection between the ceramic package 2 and the crystal unit 3 are performed by adding an Ag powder or the like to a resin such as a silicon-based, epoxy-based, or polyimide-based resin and applying a conductive resin paste. This is achieved by the cured conductive adhesive member 4. Specifically, the above-described conductive resin paste is supplied onto the electrode pads 22 and 23 on the surface of the substrate 21 by a dispenser or the like, and the electrode pads 22 and 23 are supplied.
The quartz oscillator 3 is placed on the conical conductive resin paste raised on the top 23 so that the extraction electrode extended from the lower surface on one short side of the quartz oscillator 3 is in contact with the conductive resin paste. The resin paste is cured.

Here, the conductive adhesive member 4 is provided between the lead electrodes 32, 34 on the lower surface of the crystal unit 3 and the electrode pads 22, 23 on the surface of the substrate 21 of the ceramic package 2, for example, the height of the bump 5. As shown in FIG. 4, it is disposed so as to straddle one short-side end surface portion and one long-side end surface of the quartz oscillator 3 as shown in FIG. That is, in the planar state of the crystal unit 3, the conductive adhesive member 4 is attached to the end surface of the crystal unit 3 in a substantially L shape. In the drawing, 4a indicates a conductive adhesive member attached to one short side end surface portion of the crystal resonator 3, and 4b indicates a conductive adhesive member attached to a long side end surface portion. Further, the conductive adhesive member 4 is not substantially attached to the surface of the crystal unit 3.

As a result, the pair of excitation electrodes 31 and 33 of the crystal unit 3 are electrically connected to the external terminal electrodes 26 on the outer surface of the ceramic package 2 via the electrode pads 22 and 23.

Actually, after the crystal resonator 3 is electrically connected and mechanically connected to the electrode pads 22 and 23, the oscillation frequency of the crystal resonator 3 is measured using the external terminal electrodes 26 and the like. If necessary, Ag or the like is deposited on the surface of the upper excitation electrode 31 of the crystal unit 3 to adjust the frequency.

The metal lid 6 is made of substantially flat metal,
For example, Fe-Ni alloy (42 alloy) or Fe-Ni-C
o Alloy (Kovar) or the like. Such a metal lid 6 has a housing area (cavity portion) 2 for the crystal unit 3.
0 is hermetically sealed with nitrogen gas or vacuum. 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, and the brazing material melted by welding may be used as the metal lid 6.
A Ni plating layer may be formed on the surface side of the metal lid 6 so that the brazing material contributing to the joining does not decrease due to wraparound.

According to the above-described structure, the electrode pad 22 and the electrode pad 22 are provided on the surface of the substrate 21 which is a part of the ceramic package 2.
23, the extraction electrode 3 of the crystal unit 3
2, 34 are electrically and mechanically joined via a conductive adhesive member 4 formed by curing a conductive resin paste.

More specifically, the conductive adhesive member 4 is electrically conductive on the lower surface of the crystal unit 3 and on the end surfaces on both short sides of the one side, that is, on the short side end surface and the long side end surface. The adhesive members 4a and 4b are arranged. That is, the bonding between the ceramic package 2 and the crystal unit 3 is performed on one short side end face and two long side end faces in a plan view, and a fillet is formed at a total of three end faces (conductive at the end face portions). The resin paste is raised) is achieved.
In terms of thickness, bonding is also performed on the surface of the substrate 21 of the ceramic package 2 and the lower surface of the crystal unit 3. Thereby, the bonding strength is improved, and when an external impact is applied due to dropping or the like, peeling is less likely to occur at this bonding portion, and the oscillation frequency does not greatly change or oscillation failure does not occur. .

At the same time, the conductive adhesive member 4 adheres only to the lower surface and the end surface of the crystal unit 3, but does not substantially adhere to the surface side. For this reason, since the conductive resin paste serving as the conductive adhesive member 4 does not spread from the extraction electrode 32 to the excitation electrode 31, there is no unnecessary deposit on the surface. Crystal impedance) fluctuations can be effectively suppressed. Thus, the oscillation characteristics do not change.

The spread of the conductive resin paste on the lower surface side of the crystal unit 3 is formed by forming the bump 5 in a band shape near the center of the electrode pads 22 and 23 so that the lower surface side of the crystal unit 3 can be formed. The protrusion of the conductive resin paste can be suppressed.

As a result, the conductive resin paste is applied to the whole of the crystal unit 3 by the excitation electrodes 31 and 3 of the crystal unit 3.
The area where the conductive resin paste is adhered to the crystal resonator 3 can be reduced without spreading to the side of the crystal resonator 3.

In order to regulate the portion where the conductive adhesive member 4 adheres to the crystal unit 3 in this manner, one short side end of the crystal unit 3 is placed on the conductive resin paste during the manufacturing process. This is achieved by controlling the position where

The above-described crystal oscillator is manufactured as follows.

First, the excitation electrodes 3 are provided on both main surfaces of the quartz substrate 30.
1 and 33, and a quartz oscillator 3 having extraction electrodes 32 and 34 extending to both main surfaces on one short side is prepared. Also,
At the same time, the bottom of the ceramic package 2, that is, the substrate 2
A ceramic package 2 having a pair of electrode pads 22 and 23 formed on the surface of the substrate 1, a sealing conductor film 24 and a seal ring 25 formed on the surface around the opening of the cavity 20, and a metal lid 6 is prepared.

Next, a conductive resin paste for forming the conductive adhesive member 4 is supplied and applied to the electrode pads 22 and 23 with a dispenser or the like. At this time, the supplied conductive resin paste has a generally conical shape that is entirely raised.

Next, the quartz oscillator 3 is placed on the conductive resin paste supplied in a substantially conically raised shape. Specifically, the crystal oscillator 3 is placed so that the pair of extraction electrodes 32 and 34 abut on the portion where the conductive resin paste is supplied. At the same time, as shown in FIGS. 5A and 5B, the relationship between the supplied conductive paste 40 serving as the conductive adhesive 4 and the short side end of the crystal unit 3 is controlled.

As is apparent from FIG. 5, the corners x at both ends of one of the short sides of the quartz oscillator 3 are in the width direction on the short side with respect to the center O of the supplied conductive resin paste 40. To Δ
It is placed so as to be located at the outer position by w in the longitudinal direction of the long side by Δl. Thereby, the amount of the conductive resin paste located outside can be reduced,
Fillets of stable conductive resin paste can be formed not only on the lower surface of the crystal unit 3 but also on the short side end surface and the long side end surface. In addition, the conductive resin paste which protrudes extremely from the end face of the crystal unit 3 to the surface can be effectively suppressed. In this way, the above-described positional relationship between the conductive adhesive members 4 can be easily achieved.

Next, the conductive resin paste is cured, and the ceramic package 2 and the quartz oscillator 3 are fixedly joined. Specifically, it is cured by application of heat.

Then, in a predetermined atmosphere, the seal ring 2
A metal lid 6 is placed on 5 and both are seam-welded.

In the conventional crystal oscillator, a conductive resin paste is applied on the electrode pads, the crystal oscillator is mounted, and then the conductive resin paste is applied from the front side of the crystal oscillator. The conductive resin paste is supplied again so as to conduct with the conductive resin paste.

On the other hand, in this embodiment, the electrical connection and the mechanical joining of the crystal unit can be performed by one application of the conductive resin paste. The number can be reduced.

In the above embodiment, the quartz oscillator 3 is mechanically fixed to the electrode pad only on one short side.
That is, one short side of the crystal resonator 3 is a fixed connection end, and the other short side is a vibration free end. Thus, the crystal resonator 3 can be said to be a cantilever fixed type. As described above, in the cantilever fixed type, the substrate 21 and the excitation electrode 33 on the lower surface side of the crystal unit 3 are separated by a predetermined distance, for example, 10 to 3 times.
The interval can be 0 μm. This is because when the conductive resin paste on one short side hardens to form the conductive adhesive member 4, the conductive resin paste shrinks and the stress acts. This stress acts to attract the vibration free end to the fixed connection end, and for example, the electrode pad 2
The bump 5 formed near the center of 2, 23 serves as a fulcrum,
It works so as to lift the vibration free end, which is the other short side end.

Thus, there is no problem even if the substrate 21 located below the crystal unit 3 is flat, and the substrate 21 has a two-layer structure in order to form the steps 55 and 56 as in the prior art. No need. As a result, the height of the crystal unit can be reduced.

In the present invention, the excitation electrodes 31 and 3
3, extraction electrodes 32, 3 extending to both main surfaces on the short side
4 is routed through the end face on the long side of the crystal resonator 3, and no electrode is formed on the short side end face of the crystal resonator 3. This is to satisfy the following two phenomena. One is that, when the adhesive force of the conductive resin paste is compared between the portion where the metal is formed (electrode) and the exposed portion of the quartz substrate, the exposed portion of the quartz substrate is strong. One is that at one end of the crystal unit 3, the length of the conductive adhesive member 4a on the short side end surface to be arranged in an L-shape,
Comparing with the length of the conductive adhesive member 4b on the long side end surface, shortening the length of the conductive adhesive member 4b on the long side end surface is more characteristically advantageous because the distance from the excitation electrodes 31 and 33 is increased. Becomes Therefore, by exposing the quartz substrate 30 to the end face of the quartz oscillator 3 on the side of the conductive adhesive member 4a on the short side where the joining distance is long, the conductive resin paste is mainly adhered at this portion. Joint strength increases, at the same time,
The force of lifting the long side end as a free end increases,
This is advantageous for a cantilever fixed type crystal unit, and furthermore, the characteristics are stabilized.

FIG. 6 is a sectional view of another crystal resonator according to the present invention. In this embodiment, the structure is such that the electrode pads 22 and 23 and the sealing conductor film 24 are not short-circuited via the conductive adhesive member 4. That is, as is clear from FIG. 6, the first band-shaped bump 5a is provided near the center of the electrode pads 22, 23, and the electrode pads 22, 2 are provided.
A second band-shaped bump 5b is provided near the outside of the third. On the electrode pads 22 and 23, two bumps 5a and 5b extending in the width direction on the short side of the crystal unit 3 are formed.

The two bumps 5a and 5b serve as dams, and the conductive resin paste supplied therebetween regulates the spread and prevents a short circuit with the sealing conductor film 24. ing. Incidentally, the structure of the two bumps 5a and 5b is as follows.
It is formed in the same structure and in the same process as the bump member shown in FIG.

FIG. 7 is a sectional view of a crystal oscillator showing another embodiment of the piezoelectric device of the present invention.

In this embodiment, FIGS. 1 to 6 show a quartz oscillator in which only the quartz oscillator 3 is housed in the container 2. On the other hand, FIG. 7 shows a crystal oscillator in which a dedicated cavity 8 for accommodating an oscillation circuit is formed on the lower surface side of the container.

The ring-shaped ceramic body 27 is integrated with the substrate 21 as a partition substrate so that another cavity 8 is formed on the lower surface side of the substrate 21. An external terminal electrode 2 is provided on the lower surface of the ring-shaped ceramic body.
6 are formed. Although the wiring pattern on the ceiling surface of the cavity 8 is omitted, the substrate 21 is laminated to provide the substrate 28 in order to cope with the complexity of the wiring pattern.

An IC for performing temperature compensation of the oscillation characteristics of the crystal unit 3 (operation for flattening the frequency-temperature characteristics of the crystal unit in a predetermined temperature range) is provided in the cavity 8. A chip capacitor, a chip resistor (7 in the figure) necessary for an element, an IC element for amplifying the output of the crystal unit, and a control circuit for achieving such an operation.
Described).

That is, the present invention is applied not only to a crystal oscillator having only the crystal resonator 1 but also to a crystal oscillator incorporating an oscillation circuit having a predetermined operation.

In the above embodiment, a quartz oscillator was used as the piezoelectric oscillator. However, the present invention is not limited to the quartz oscillator. For example, a piezoelectric ceramic oscillator using a piezoelectric ceramic substrate, a piezoelectric single crystal substrate May be used as the piezoelectric single crystal vibrator.

[0073]

As described above, according to the present invention, a conductive resin paste is applied to the electrode pads provided on the surface of the substrate, and the lower surface and the longer side end face and the shorter side end face of the piezoelectric vibrator are straddled. As described above, the piezoelectric vibrator was placed on the conductive resin paste, and the conductive resin paste was cured to form a conductive adhesive member. That is, the piezoelectric vibrator is joined to the electrode pad of the substrate by a conductive adhesive member disposed so as to straddle the lower surface, the long side end surface, and the short side end surface. Therefore, even if an external impact such as a drop is applied, separation between the piezoelectric vibrator and the electrode pad of the ceramic package can be prevented. Also, a large fluctuation of the oscillation frequency of the piezoelectric vibrator does not occur.

Further, since a conductive adhesive member adheres to the end face on the side of the piezoelectric vibrator and the end face on the long side thereof, and the conductive resin paste does not contact or approach the excitation electrode, damping of the fundamental wave of oscillation is performed. Smaller.

If the relationship between the conductive resin paste serving as the conductive adhesive member and the short-side corner of the piezoelectric vibrator is strictly controlled, the above-described joint structure can be easily obtained, and The resulting piezoelectric device has excellent impact properties and can derive stable characteristics.

[Brief description of the drawings]

FIG. 1 is a top view of a quartz oscillator, which is a piezoelectric device according to the present invention, in a state where a lid is omitted.

FIG. 2 is a sectional view of a crystal resonator according to the present invention.

FIG. 3 is a partial perspective view of one short side of a quartz oscillator which is a piezoelectric oscillator used in the present invention.

FIG. 4 is a perspective view showing a joined state of the piezoelectric vibrator of the present invention with a conductive adhesive member.

FIG. 5 shows the relationship between the piezoelectric vibrator of the present invention and a conductive resin paste, wherein (a) is a plan view thereof;
(B) is a side view.

FIG. 6 is a sectional view showing another embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating an example of another piezoelectric device (a crystal oscillator including an oscillation circuit) according to the present invention.

FIG. 8 is a top view of a quartz oscillator, which is a conventional piezoelectric device, in a state where a lid is omitted.

FIG. 9 is a sectional view of a conventional piezoelectric device.

FIG. 10 is a top view of a state in which a lid of a quartz oscillator which is another conventional piezoelectric device is omitted.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Crystal oscillator 2 ... Ceramic package 20 ... Cavity part 21 ... Substrate 22, 23 ... Electrode pad 24 ... Sealing conductive film 25 ... Seal ring 3 ... Quartz oscillator 30 ・ ・ ・ Crystal substrates 31, 33 ・ ・ ・ Excitation electrodes 32,34 ・ ・ ・ Extraction electrodes 4 ・ ・ ・ Conductive adhesive members 5 ・ ・ ・ Bumps 5a, 5b ・ ・ ・ Bumps 6 ・ ・ ・ Metal Cap 52: Ceramic package 53: Quartz crystal unit 54: Electrode pattern 55: Step for fixing 56: Step on the tip side 57: Conductive adhesive member 58, 59 ··groove

Claims (2)

[Claims] 1. A piezoelectric vibrator in which excitation electrodes are formed on both main surfaces of a rectangular piezoelectric substrate, and an extraction electrode connected to the excitation electrode is formed on the lower surface on one short side, and a pair of piezoelectric vibrators is formed on the surface of the substrate. A container in which the electrode pad is formed, wherein the extraction electrode of the piezoelectric vibrator and the electrode pad are connected to each other via a conductive adhesive member, wherein the conductive adhesive member A piezoelectric device, wherein the piezoelectric device is arranged so as to straddle a lower surface of a child, the short side end surface, and the long side end surface. 2. A step of preparing a piezoelectric vibrator in which excitation electrodes are formed on both main surfaces of a rectangular piezoelectric substrate, and an extraction electrode connected to the excitation electrode is formed on the lower surface on one short side of the piezoelectric substrate. A step of preparing a substrate on which a pair of electrode pads are formed; a step of supplying a conductive resin paste to be a conductive adhesive member to the pair of electrode pads; And a step of curing the conductive resin paste, wherein the corners at both ends of one short side of the piezoelectric vibrator are closer to the center of the supplied conductive resin paste. The piezoelectric device is also mounted at a position outward in both the width direction and the longitudinal direction.