JP3351273B2 - Manufacturing method of piezoelectric resonance component - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric resonance component used for constructing a transmission circuit, a filter circuit, and the like, and a method of manufacturing the same. More particularly, the present invention relates to a highly reliable piezoelectric resonance portion in which deterioration of resonance characteristics is suppressed. The present invention relates to a method for manufacturing a product .

[0002]

2. Description of the Related Art Heretofore, oscillators and filters using a single crystal such as quartz have been widely used in mobile communication equipment and OA equipment. However, an oscillator and a filter using a single crystal such as quartz require a high level of polishing technique and are very expensive because they pursue frequency stability. However, in recent years, with the spread of mobile communication devices and OA devices, inexpensive oscillators and filters have been demanded, especially for mobile phones whose demand has been increasing in recent years. For this reason, piezoelectric resonance components, which constitute an oscillator or a filter using piezoelectric ceramics that have been used for general equipment and home electric appliances, have been widely used in the mobile communication field and the OA equipment field. Was.

[0003] The conventional piezoelectric resonator component according to Japanese Unexamined Patent Publication No. 7-336180 will be described with reference to FIGS. 3 to 5. FIG. 3 is an exploded perspective view showing the configuration of a conventional intermediate laminate of piezoelectric resonance components, FIG. 4 is a perspective view showing the intermediate laminate, and FIG. 5 is a perspective view showing a conventional piezoelectric resonance component (finished product). .

In FIGS. 3 and 4 , reference numeral 1 denotes a piezoelectric resonator;
Is an excitation electrode, 3 is an extraction electrode, 4 is a sealing substrate, 5 is an adhesive layer, 6 is a vibration space, 7 is a solid filling, and 8 is an external electrode. As shown in FIGS. 3 and 5 , a conventional intermediate laminate of a piezoelectric resonance component includes a piezoelectric resonator 1 and a pair of sealing substrates 4 that sandwich the piezoelectric resonator from both main surfaces thereof.
And an adhesive layer 5 for bonding the sealing substrate 4 with the sealing substrate 4. The piezoelectric resonator 1 has, as a base material, a piezoelectric substrate made of a piezoelectric ceramic material such as PZT, and has upper and lower surfaces of the piezoelectric substrate as main surfaces, respectively. Excitation electrodes 2 are formed at the center of each of the upper and lower surfaces of the piezoelectric substrate.
Further, extraction electrodes 3 are formed on different edges of the upper and lower surfaces of the piezoelectric substrate, and the excitation electrodes 2 and the extraction electrodes 3 on the upper and lower surfaces of the piezoelectric substrate are electrically connected to each other.

The sealing substrates are ceramic substrates such as alumina and dielectric materials, respectively, and are formed on a rectangular flat plate having substantially the same shape and size as the piezoelectric resonator. As shown in FIG. 3 , the surface of the sealing substrate 4 facing the piezoelectric resonator 1 has an adhesive layer 5 except for a substantially circular portion (hereinafter referred to as a vibration space) 6 facing the excitation electrode 2. Are formed. The solid filler 7 is substantially uniformly dispersed in the adhesive constituting the adhesive layer 5. The solid filling 7 has a substantially spherical outer shape, and has a size corresponding to the height at which the piezoelectric resonator 1 can vibrate (the height of the vibration space 6). The solid filler 7 functions as a spacer, and keeps the thickness of the adhesive layer 5 bonded to the sealing substrate 4 and the piezoelectric resonator 1, that is, the height of the vibration space 6 formed in the adhesive layer 5 constant. In addition, when the piezoelectric resonator 1 and the sealing substrate 4 are pressurized, the vibration is prevented from being hindered by the adhesive being pushed into the vibration space 6.

An external electrode 8 is formed on an end face of the laminate by, for example, a wet film forming method such as a plating method or a dry film forming method such as a sputtering method. As a result, as shown in FIG. 5 , a conventional piezoelectric resonance component is completed. The piezoelectric resonance component having the external electrodes 8 formed thereon is mounted on a printed wiring board by soldering.

[0007]

In the above-described conventional piezoelectric resonance component, it is generally assumed that an epoxy resin or the like is used for an adhesive layer in a step of bonding the sealing substrate and the piezoelectric substrate when forming a vibration space. Has become. For thermosetting resin,
Curing at a predetermined temperature and a predetermined time, the process is,
When the temperature is increased from about room temperature, the viscosity once decreases, and when the temperature exceeds a certain temperature, the viscosity increases again and the resin is completely cured. Also, the gas in the cavity follows the equation of state, and it is known that the pressure in a certain volume is proportional to the temperature of the gas as known by Charles' law. In other words, when the adhesive layer is cured, heating reduces the viscosity of the adhesive layer and at the same time raises the pressure in the cavity, so that the air in the cavity leaks outside and the airtightness is impaired. Had.

[0008] The present invention has been made to solve the above prior art problems, high airtightness of trust, a manufacturing method of the piezoelectric resonator unit products resonance characteristic is stabilized, it can be produced with good reproducibility The purpose is to provide.

[0009]

In order to solve this problem, a piezoelectric resonance component according to the present invention is provided on both sides of a piezoelectric substrate.
Providing electrodes and forming a piezoelectric resonator;
Adhesive layers on both sides of the piezoelectric substrate even in a low pressure atmosphere
The piezoelectric resonance by laminating the sealing substrate through
Creates a vibration space for the element and pressurizes it at atmospheric pressure or in a pressurized tank
To increase the pressure inside the vibrating space from the atmospheric pressure.
And a step of hardening the adhesive layer.
And a method for manufacturing a piezoelectric resonance component .

Further , in the above-mentioned manufacturing method, the pressure may be higher than the atmospheric pressure.
Adhesive layers on both sides of the piezoelectric substrate even in a low pressure atmosphere
When laminating the sealing substrate via
Adhesive on both sides of the piezoelectric substrate in the decompressed state or in a decompression layer
It is characterized by laminating a sealing substrate through layers
is there.

In the above method, the adhesive may be
Characterized in that the layer is a semi-cured sheet-like adhesive
Things.

[0012]

(Embodiment 1) Embodiment 1 relating to a piezoelectric resonance component of the present invention will be described.
This will be described with reference to FIGS. 1 (a), 1 (b) and 2.
FIG. 1A is a perspective view showing an intermediate laminated body of the piezoelectric resonance component according to the first embodiment, and FIG. 1B is an AA of FIG.
FIG. 2 is an exploded perspective view showing the structure.
1 (a), 1 (b) and 2, an excitation electrode 2 and an extraction electrode are provided on both main surfaces of a piezoelectric resonator 1 composed of a piezoelectric substrate formed of a piezoelectric ceramic material such as PZT in a rectangular flat plate shape. 3 are formed respectively. When a voltage is externally applied to the excitation electrode 2, a vibration mode in which only the vicinity of the excitation electrode 2 vibrates is excited. An adhesive layer 5 is provided between the piezoelectric resonator 1 and the sealing substrate 4 in a layered manner, and forms a vibration space so as not to hinder the vibration of the piezoelectric vibrator 1. As the adhesive, for example, an epoxy-based thermosetting resin is used in consideration of heat resistance and adhesive strength. Furthermore, this vibration space is formed at a pressure where the internal pressure is lower than the atmospheric pressure. When the pressure inside the vibrating space is substantially the same as the atmospheric pressure, if the adhesive layer 5 is cured at room temperature, the air in the vibrating space thermally expands and airtightness is maintained without leaking to the outside. It is. However, in general, when a thermosetting resin is used for the adhesive layer, heating is required for curing the adhesive layer, and at this time, the gas in the vibration space expands thermally and may leak to the outside. May be inhibited. Therefore, in the first embodiment, since the pressure inside the vibration space is formed at a pressure lower than the atmospheric pressure,
Even if the gas in the vibrating space is thermally expanded during curing of the adhesive layer, the pressure will not cause deformation of the adhesive even if the gas expands, and the rate at which gas tightness is impaired due to leakage of the gas to the outside will be reduced. Can be. Further, a force having a magnitude equal to the pressure difference isotropically applied to the vibration space due to a pressure difference between the outside and the inside of the vibration space.
The degree of adhesion between the sealing plate 4 and the sealing plate 4 becomes uniform, and a vibration space with almost no deformation can be formed. Further, even after the adhesive layer is cured, the pressure is maintained due to the pressure difference between the inside and the outside of the vibration space, so that the possibility of peeling or the like is reduced. still,
It is more preferable that the adhesive layer contains a solid filler having an arbitrary shape and size in order to keep the volume of the vibration space constant before and after curing with respect to a change in viscosity upon curing of the adhesive layer. .

Second Embodiment Next, a second embodiment of the method for manufacturing a piezoelectric resonance component of the present invention will be described with reference to FIG. The second embodiment relates to a method suitable for manufacturing the piezoelectric resonance component according to the first embodiment.

In the method of manufacturing the piezoelectric resonator according to the second embodiment of the present invention, the adhesive layer 5 is formed on the two main surfaces of the piezoelectric resonator 1 to a predetermined thickness except for a portion facing the excitation electrode 2. The sealing substrate 4 is laminated on the outside of the piezoelectric resonator 1 in an atmosphere having a pressure lower than the atmospheric pressure through a material which is applied by printing or the like and heated at a specific temperature and time to a semi-cured state, and By completely heating the adhesive layer by heating at the temperature and time of the above, the adhesive layer does not flow near the excitation electrode 2,
In addition, the gas in the vibration space thermally expands, and the vibration space with airtightness can be stably formed without leaking to the outside. By adopting such a method of manufacturing a piezoelectric resonance component, it is possible to obtain the piezoelectric resonance component according to the first embodiment having stable characteristics. For example, as a method of realizing lamination in an atmosphere at a pressure lower than the atmospheric pressure, the intermediate laminated body before lamination is sealed in a decompression pack and pressurized in the atmospheric pressure or in a pressurized tank by pressurizing in an atmospheric pressure or a pressure tank. The pressure can be below atmospheric pressure. In addition, in forming the adhesive layer, the same effect can be obtained by using a sheet-like adhesive in a semi-cured state in addition to printing. In this case, the desired effect can be obtained by laminating the intermediate laminate in a reduced-pressure tank. A vibration space can be formed.

Reference Example Next, a reference example relating to a method for manufacturing a piezoelectric resonance component of the present invention will be described with reference to FIG. The reference example relates to a method suitable for manufacturing the piezoelectric resonance component according to the first embodiment, as in the second embodiment. Therefore, description of portions common to the manufacturing method according to the second embodiment will be omitted.

In the method of manufacturing a piezoelectric resonator according to the reference example of the present invention, a semi-cured adhesive layer 5 is formed on two main surfaces of a piezoelectric vibrator 1 except for a portion facing the excitation electrode 2. Then, at a temperature higher than the temperature at which the adhesive layer 5 is cured, the sealing substrate 4 is laminated on the outside of the piezoelectric resonator 1, and heated at a specific temperature and time to cure the adhesive layer. , Forming a vibration space.

In the method of manufacturing a piezoelectric resonance component according to the above reference example , since all the steps are performed at atmospheric pressure, the sealing substrate and the piezoelectric resonator must be laminated at a high temperature via an adhesive layer. The piezoelectric resonance component according to the first embodiment having stable characteristics can be easily obtained without performing the process in the atmosphere at a pressure lower than the atmospheric pressure in the second embodiment.

[0018]

As described above, according to the present invention, since the vibration space is formed at a pressure lower than the atmospheric pressure, the gas in the vibration space is hardened when the adhesive layer is cured. Can be kept airtight stably without thermal expansion and leakage to the outside, and the vibration space is formed by using a piezoelectric substrate or a ceramic substrate such as alumina and a semi-cured adhesive layer to form the vibration space. This prevents deformation of the electrode and adhesion of the adhesive to the excitation electrode due to the flowing out of the adhesive, thereby stably forming a vibration space without obstructing the excitation of the electrode.

[Brief description of the drawings]

FIG. 1A is a perspective view of an intermediate laminated body of a piezoelectric resonance component according to a first embodiment of the present invention. FIG. 1B is a partial cross-sectional view taken along a line AA in FIG.

FIG. 2 is an exploded perspective view showing a structure of an intermediate laminated body of the piezoelectric resonance component according to the first embodiment of the present invention.

FIG. 3 is an exploded perspective view showing the structure of a conventional intermediate laminate of a piezoelectric resonance component.

FIG. 4 is a perspective view showing the appearance of the intermediate laminate shown in FIG. 3;

FIG. 5 is a perspective view showing the appearance of a conventional piezoelectric resonance component.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piezoelectric resonator 2 Excitation electrode 3 Leader electrode 4 Sealing substrate 5 Adhesive layer 6 Vibration space 7 Solid filling 8 External electrode

Continuation of the front page (72) Inventor Yoshihiro Bessho 1006 Kazuma Kadoma, Kazuma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-3-210809 (JP, A) JP-A-7-336180 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H03H 3/00-3/04

Claims (3)

(57) [Claims] 1. A vibrating electrode is provided on both main surfaces of a piezoelectric substrate.
Forming a piezoelectric resonator, and applying a pressure lower than the atmospheric pressure.
Sealed via an adhesive layer on both sides of the piezoelectric substrate in an atmosphere
The vibration space of the piezoelectric resonator is formed by stacking substrates.
And pressurize it at atmospheric pressure or in a pressurized tank.
The pressure inside the vibration space to a pressure lower than atmospheric pressure
And a step of curing the adhesive layer.
A method for manufacturing a piezoelectric resonance component . 2. The method according to claim 1 , wherein the atmosphere is at a pressure lower than the atmospheric pressure.
Laminating sealing substrates on both sides of the piezoelectric substrate via an adhesive layer
When in a sealed state in a vacuum pack or in a vacuum layer,
The sealing substrate is laminated on both sides of the piezoelectric substrate via an adhesive layer.
The method for manufacturing a piezoelectric resonance component according to claim 1, wherein 3. An adhesive in which the adhesive layer is a semi-cured sheet.
2. The method for manufacturing a piezoelectric resonance component according to claim 1, wherein the agent is an agent .