JP2000040936A - Piezo-resonator, manufacture of the piezo-resonator, piezo resonance component and manufacture of piezo- resonance part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the close-adhesiveness of a vibrating electrode and a piezoelectric substrate, to prevent peeling and to improve an electric characteris tic by providing a vibrating electrode covering layer which is made of a thermo setting resin on the piezoelectric substrate. SOLUTION: Vibrating electrodes 12 and drawing electrodes 13 are formed on both principal planes of a piezoelectric substrate 11, having piezoelectricity such as a PZT by means of a physical gas phase method such as vacuum metallizing. When voltage is applied to the electrodes 13 from the outside, voltage is also applied to the electrodes 12 and a vibration mode in which only the electrodes 12 and their neighborhood vibrate is energized. Vibrating electrode covering layers 14 are formed, so as to cover the electrodes 12 and their neighborhood. The layers 14 are obtained by curing a thermosetting resin and the electrodes 12 are firmly adhered to the substrate 11 by means of curing shrinkage at curing. As the thermosetting resin, e.g. acrylic epoxy resin is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a piezoelectric resonator used for a piezoelectric ceramic oscillator or a piezoelectric ceramic filter using an energy trapping type in a thickness vertical or thickness-shear mode, a method of manufacturing a piezoelectric resonator, and a method of manufacturing a piezoelectric resonator. The present invention relates to a method for manufacturing a resonance component and a piezoelectric resonance component.

[0002]

2. Description of the Related Art A conventionally known piezoelectric resonator and a method of manufacturing the same are disclosed in Japanese Patent Application Laid-Open No. 9-162682. Specifically, the vibrating electrode is made of silver, nickel,
Metals such as copper, chromium, and gold are formed by a physical vapor phase method such as a vacuum evaporation method and a sputtering method. This is because the thermal stress applied to the piezoelectric substrate is small. A conventionally known piezoelectric resonance component and a method for manufacturing the same are disclosed in JP-A-2-309707. Specifically, a piezoelectric resonance element having a vibration electrode formed thereon is laminated between two sealing plates having a concave portion on the side facing the piezoelectric resonance element, and an external electrode is formed on an end face of the laminate. It is constituted by doing. 5 and 6 show structural examples of such a piezoelectric resonance component. FIG. 5 is an exploded perspective view of the piezoelectric resonator and the sealing plate before lamination. FIG. 6 is a sectional view of the piezoelectric resonance component. In the figure, 11 is a piezoelectric substrate, 12 is a vibration electrode, 13 is an extraction electrode, 16
Is a sealing plate, and 18 is an external electrode. On the side of the sealing plate 16 facing the piezoelectric substrate 11, a concave portion serving as a vibration space is formed, and a resin layer 15 is applied around the concave portion. These are laminated and cured by heating to form the piezoelectric resonator 11.
And the sealing plate 14 are bonded.

[0003]

However, in the prior art, since the adhesion between the piezoelectric substrate and the vibrating electrode is poor, there is a problem that the vibrating electrode is peeled off by a thermal shock related to a temperature difference in a heat cycle test or the like. .

[0004] Further, even when peeling does not occur, there is a problem of deterioration of electrical characteristics such as a decrease in energy confinement due to low adhesion, an increase in resonance impedance and a decrease in mechanical quality factor (Qm).

[0005] Further, since a recess is formed in the sealing plate,
When heat is applied, distortion such as warpage or undulation occurs, and there is a problem that the sealing performance between the piezoelectric resonator and the sealing plate is impaired.

In view of the above-mentioned problems of the conventional piezoelectric resonator and piezoelectric resonator component, the present invention improves the adhesion between the vibrating electrode and the piezoelectric substrate, improves the effect of preventing peeling and the electrical characteristics. It is an object of the present invention to provide an improved piezoelectric resonator, a method for manufacturing a piezoelectric resonator, a piezoelectric resonance component, and a method for manufacturing a piezoelectric resonance component. It is another object of the present invention to provide a piezoelectric resonance component and a method for manufacturing the piezoelectric resonance component, which can ensure the hermeticity between the piezoelectric resonator and the sealing plate due to warpage or the like.

[0007]

To achieve the above object, a first present invention (corresponding to the first aspect of the present invention).
Has a piezoelectric substrate, a vibration electrode facing the piezoelectric substrate and an extraction electrode connected to the vibration electrode,
A piezoelectric resonator comprising: a piezoelectric resonance element; and a vibration electrode covering layer made of a thermosetting resin formed on the piezoelectric substrate so as to cover at least the vibration electrode.

According to a second aspect of the present invention (corresponding to the second aspect of the present invention), a piezoelectric resonance element includes a piezoelectric substrate, a vibration electrode opposed to the piezoelectric substrate, and a lead electrode connected to the vibration electrode. A resin forming step of forming a thermosetting resin on the piezoelectric substrate so as to cover at least the vibration electrode; and a resin curing step of curing the thermosetting resin after the resin forming step. A method for manufacturing a piezoelectric resonator, characterized in that:

A third aspect of the present invention (corresponding to the third aspect of the present invention) is a piezoelectric resonance element having a piezoelectric substrate, a vibration electrode opposed to the piezoelectric substrate, and a lead electrode connected to the vibration electrode. And a vibrating electrode coating layer of a thermosetting resin formed so as to cover at least main portions of both main surfaces of the piezoelectric substrate, wherein the vibrating electrode coating layer is provided on at least a vibration region of the piezoelectric resonance element. A piezoelectric resonance component characterized by having a concave portion.

A fourth aspect of the present invention (corresponding to the fourth aspect of the present invention) is characterized in that a flat sealing plate is provided on each of the vibrating electrode coating layers. It is a piezoelectric resonance component.

A fifth aspect of the present invention (corresponding to the fifth aspect of the present invention) is a piezoelectric resonance element having a piezoelectric substrate, a vibration electrode opposed to the piezoelectric substrate, and a lead electrode connected to the vibration electrode. A resin forming step of forming a thermosetting resin so as to cover both main surfaces of the piezoelectric substrate,
After the resin forming step, a resin curing step of curing the thermosetting resin, and after the resin curing step, the thermosetting resin on the vibration region of the piezoelectric resonance element is partially removed to form a recess. And a recess forming step of forming a piezoelectric resonator component.

A sixth aspect of the present invention (corresponding to the sixth aspect of the present invention) includes a sealing plate bonding step of bonding a sealing plate on the thermosetting resin after the recess forming step. A fifth aspect of the present invention is a method for manufacturing a piezoelectric resonance component according to the present invention.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) First, the first embodiment of the present invention will be described.
An embodiment will be described with reference to the drawings. FIG. 1 is a sectional view of a piezoelectric resonator according to the first embodiment of the present invention. In FIG. 1, 11 is a piezoelectric substrate, 12 is a vibration electrode, 13 is a lead electrode, and 14 is a vibration electrode coating layer. Hereinafter, the configuration of the piezoelectric resonator according to the present embodiment will be described together with its operation.

A piezoelectric substrate 11 having piezoelectricity such as PZT
The vibration electrode 12 and the extraction electrode 13 are provided on both main surfaces of
It is formed by a physical vapor phase method such as vacuum evaporation. When a voltage is externally applied to the extraction electrode 13, a voltage is also applied to the vibration electrode 12, and a vibration mode in which only the vibration electrode 12 and its vicinity vibrate is excited. A vibrating electrode coating layer 14 is formed so as to cover the vibrating electrode 12 and its vicinity. The vibrating electrode coating layer 14 is formed by curing a thermosetting resin, and the vibrating electrode 12 is firmly adhered to the piezoelectric substrate 11 by curing shrinkage during curing.

In this embodiment, an acrylic epoxy resin is used as the thermosetting resin, but a thermosetting resin such as an epoxy resin or a melamine alkyd resin may be used. In order to prevent the occurrence of such a problem, excellent adhesion between a resin having high hardness such as a melamine resin or a urea resin and a vibrating electrode material formed of a metal such as silver or nickel such as an acrylic resin or an epoxy resin is excellent. A resin composite resin is desirable. The curing temperature is desirably 150 ° C. or lower. The curing shrinkage is 3
0% or less is desirable. The reason is that if the curing shrinkage is large,
Stress is applied to the piezoelectric substrate, causing cracks in the piezoelectric substrate,
This is because unnecessary vibration occurs.

The thickness of the vibrating electrode coating layer 14 is
On the other hand, the thickness is preferably 20 μm or less. For example, 20MHz
In the case of the resonator of the above, it was confirmed by experiments that the resonance impedance rapidly deteriorated when the thickness exceeded 20 μm.

According to the piezoelectric resonator of this embodiment,
It was confirmed that strong contact between the vibration electrode 12 and the piezoelectric substrate 11 can be ensured, and that the peeling failure is eliminated and the resonance impedance is improved by about 10% as compared with the case where the vibration electrode coating layer 14 is not formed.

Next, a method of manufacturing the piezoelectric resonator according to the present embodiment will be described with reference to FIG. FIG.
FIG. 4 is a process cross-sectional view illustrating the method for manufacturing the piezoelectric resonator according to the first embodiment of the present invention.

First, as shown in FIG. 2A, a vibrating electrode 12 and a lead electrode 13 are formed on both main surfaces of a piezoelectric substrate 11 such as PZT by a physical vapor phase method such as vacuum evaporation. Form.

Next, as shown in FIG. 2B, a thermosetting resin 20 is formed so as to cover the vibrating electrode 12 and its vicinity (corresponding to the resin forming step of the present invention). As a forming method, for example, a screen printing method is used.

Next, as shown in FIG. 2C, the thermosetting resin 20 formed by the screen printing method is heated and cured to form the vibrating electrode coating layer 14. Thereby, the piezoelectric resonator according to the present embodiment is obtained (corresponding to the resin curing step of the present invention). The curing temperature in this step is 150
C or lower is desirable.

According to the method of manufacturing the piezoelectric resonator of the present embodiment, the vibrating electrode 12 and the piezoelectric substrate 11 can be firmly adhered to each other. About 10% impedance
It was confirmed that it improved.

The vibrating electrode coating layer 14 is
In order to give a mass load effect to 2, the frequency can be adjusted by reducing the mass by partially removing the mass as needed. As a method for reducing the mass, removal by irradiation with a laser beam is desirable.

In the present embodiment, the vibrating electrode coating layer of the present invention has been described as being formed so as to cover the vibrating electrode and its vicinity. However, the present invention is not limited to this. May be formed over the entire main surface. In short, what is necessary is just to form on the piezoelectric substrate so as to cover at least the vibration electrode.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
An embodiment will be described with reference to the drawings.

FIG. 3 is a sectional view of a piezoelectric resonance component according to a second embodiment of the present invention. In FIG. 3, 11
Is a piezoelectric substrate, 12 is a vibration electrode, 13 is a lead electrode, 14 is a vibration electrode coating layer, 15 is an adhesive resin layer,
6 is a sealing plate, 17 is a vibration space, and 18 is an external electrode. In this embodiment, members having basically the same functions as those in the first embodiment are denoted by the same reference numerals.

A piezoelectric substrate 11 having piezoelectricity such as PZT
The vibration electrode 12 and the extraction electrode 13 are provided on both main surfaces of
It is formed by a physical vapor phase method such as vacuum evaporation. When a voltage is externally applied to the extraction electrode 13, a voltage is also applied to the vibration electrode 12, and a vibration mode in which only the vibration electrode 12 and its vicinity vibrate is excited. A vibrating electrode coating layer 14 is formed on the entire surfaces of both main surfaces of the piezoelectric substrate 11. The vibrating electrode coating layer 14 is formed by curing a thermosetting resin.
1 is firmly adhered. Then, the vibrating electrode 12 to be excited and a part of the vibrating electrode coating layer formed on the vicinity thereof are removed to form a vibrating space 17. The surface of the vibrating electrode coating layer 14 that has not been removed and the sealing plate 16 are adhered by the adhesive resin layer 15 to seal the vibrating space 17. In the present embodiment, a flat plate made of alumina is used as the sealing plate 16, but a flat plate made of dielectric ceramics may be used when it is desired to add a capacitance to the piezoelectric resonance component. Further, a flat plate of a resin or a resin composite material, such as a glass epoxy substrate as a printed wiring board material, can also be used. The external electrode 18 is configured so that it can be electrically connected to a part of the extraction electrode.

In the present embodiment, an acrylic epoxy resin is used as the thermosetting resin. However, a thermosetting resin such as an epoxy resin or a melamine alkyd resin may be used. In order to prevent this, excellent adhesion between a resin having high hardness such as melamine resin or urea resin and a vibration electrode material made of a metal such as silver or nickel such as an acrylic resin or an epoxy resin. A resin composite resin is desirable. The curing temperature is desirably 150 ° C. or lower. The curing shrinkage is 3
0% or less is desirable. The reason is that if the curing shrinkage is large,
This is because stress is applied to the piezoelectric substrate 11 to cause cracking of the piezoelectric substrate 11 or unnecessary vibration. The thickness of the vibrating electrode coating layer 14 is 20 μm on the vibrating electrode 12.
The following is desirable.

The piezoelectric resonance component according to the present embodiment eliminates concave portions in the sealing plate 16, so that warpage and other distortions do not occur, and the hermeticity between the piezoelectric substrate 11 and the sealing plate 16 can be ensured. Further, strong contact between the vibrating electrode 12 and the piezoelectric substrate 11 can be ensured, and the vibrating electrode coating layer 1
It was confirmed that the separation failure was eliminated and the resonance impedance was improved by about 10% as compared with the case where No. 4 was not formed.

Next, a method for manufacturing a piezoelectric resonance component according to the present embodiment will be described with reference to FIG. FIG.
FIG. 9 is a process cross-sectional view illustrating the method for manufacturing the piezoelectric resonance component according to the second embodiment of the present invention.

First, as shown in FIG. 4A, a piezoelectric substrate 11 having a piezoelectric property such as PZT is prepared.
As shown in FIG.
2 and the extraction electrode 13 are formed by a physical vapor phase method such as vacuum evaporation.

Next, as shown in FIG. 4 (c), a thermosetting resin is formed on the entire both main surfaces of the piezoelectric substrate 11 and cured to form the vibrating electrode coating layer 14. (Corresponding to the resin forming step and the resin curing step of the present invention). Since the vibrating electrode coating layer 14 is obtained by curing a thermosetting resin,
The vibrating electrode 12 is firmly adhered to the piezoelectric substrate 11 by curing shrinkage during curing.

Next, as shown in FIG. 4D, a vibrating space 17 is formed by removing the vibrating electrode 12 to be excited and a part of the vibrating electrode coating layer 14 formed on the vicinity thereof. (Corresponding to the recess forming step of the present invention).

Next, as shown in FIG. 4E, an adhesive resin layer 15 is formed on the surface of the vibration electrode coating layer 14 which has not been removed.
To form

Next, as shown in FIG.
6 and heated under pressure to cure the adhesive resin layer 14, and integrated as shown in FIG.
(It corresponds to the sealing plate bonding step of the present invention together with (e).) The curing temperature in this step is 150 ° C. or less, and the pressure is 5
Desirably at least atmospheric pressure.

Next, as shown in FIG. 4H, by manufacturing the external electrode 18 so that it can be electrically connected to a part of the extraction electrode 13, the piezoelectric resonance component of this embodiment can be obtained. Can be

According to the method of manufacturing a piezoelectric resonance component in the present embodiment, since there is no recess in the sealing plate 16, distortion such as warpage does not occur, and the piezoelectric substrate 11 and the sealing plate 16 are not deformed.
Can secure the sealing performance. Also, the vibrating electrode 1
It was confirmed that strong adhesion between the piezoelectric substrate 11 and the piezoelectric substrate 11 could be secured, and that the separation failure was eliminated and the resonance impedance was improved by about 10% as compared with the case where the vibrating electrode coating layer 14 was not formed.

The vibrating electrode coating layer 14 is
In order to give a mass load effect to 2, the frequency can be adjusted by partially removing the mass as necessary and reducing the mass. As a method for reducing the mass, removal by irradiation with a laser beam is desirable.

In the present embodiment, the vibrating electrode coating layer of the present invention has been described as being formed over the entire surfaces of both main surfaces of the piezoelectric substrate. However, the present invention is not limited to this. What is necessary is just to be able to be formed and to be well adhered to the sealing plate of the present invention. In short, it is only necessary that the piezoelectric substrate be formed so as to cover at least the main parts of both main surfaces of the piezoelectric substrate.

In the present embodiment, the piezoelectric resonance component of the present invention has been described as including the sealing plate of the present invention. However, the present invention is not limited to this. For example, the piezoelectric resonance component is mounted. It suffices if the structure has a member having the function of a sealing plate.

[0042]

As is apparent from the above description, the present invention according to claims 1 and 2 improves the adhesion between the vibrating electrode and the piezoelectric substrate, improves the effect of preventing peeling, and improves the electrical characteristics. A method for manufacturing a resonator or a piezoelectric resonator can be provided. That is, due to the curing shrinkage of the thermosetting resin on the vibrating electrode, the adhesion between the vibrating electrode and the piezoelectric substrate is improved, and the effect of preventing peeling and the electrical characteristics are improved. Further, since the surface of the vibration electrode is covered with the resin, there is also an effect of preventing corrosion of the vibration electrode.

The present invention according to claims 3 to 6 provides a piezoelectric resonance component or a method of manufacturing a piezoelectric resonance component in which the adhesion between the vibrating electrode and the piezoelectric substrate is improved, the effect of preventing separation and the electrical characteristics are improved. can do. That is, due to the curing shrinkage of the thermosetting resin on the vibrating electrode, the adhesion between the vibrating electrode and the piezoelectric substrate is improved, and the effect of preventing peeling and the electrical characteristics are improved. Further, since the surface of the vibration electrode is covered with the resin, there is also an effect of preventing corrosion of the vibration electrode. In addition, since the sealing plate can be made a flat plate, the sealing property between the piezoelectric resonator and the sealing plate due to warpage or the like can be ensured.

[Brief description of the drawings]

FIG. 1 is a sectional view of a piezoelectric resonator according to a first embodiment of the present invention.

FIG. 2 is a process cross-sectional view of the piezoelectric resonator according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a piezoelectric resonance component according to a second embodiment of the present invention.

FIG. 4 is a process cross-sectional view of a piezoelectric resonance component according to a second embodiment of the present invention.

FIG. 5 is an exploded perspective view of a conventional piezoelectric resonance component before lamination.

FIG. 6 is a sectional view of a conventional piezoelectric resonance component.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Piezoelectric substrate 12 Vibration electrode 13 Leader electrode 14 Vibration electrode coating layer 15 Adhesive resin layer 16 Sealing plate 17 Vibration space 18 External electrode 19 Sealing plate with concave part 20 Thermosetting resin

Continuation of the front page (72) Inventor Hiroyuki Hase 1006 Kadoma, Kazuma, Osaka Prefecture F-term (reference) in Matsushita Electric Industrial Co., Ltd. 5J033 BB04 CC04 EE03 EE04 EE07 FF01 FF11 GG03 GG08 GG16 GG18 HH03 HH04 HH05 KK02 5J04A

Claims (6)

[Claims] A piezoelectric resonator having a piezoelectric substrate, a vibrating electrode opposed to the piezoelectric substrate, and a lead electrode connected to the vibrating electrode; and a piezoelectric resonant element formed on the piezoelectric substrate so as to cover at least the vibrating electrode. A vibrating electrode coating layer made of a thermosetting resin. 2. A piezoelectric resonance element having a piezoelectric substrate, a vibrating electrode opposed to the piezoelectric substrate, and a lead electrode connected to the vibrating electrode is provided, and at least the vibrating electrode is covered on the piezoelectric substrate. A method for manufacturing a piezoelectric resonator, comprising: a resin forming step of forming a thermosetting resin; and a resin curing step of curing the thermosetting resin after the resin forming step. 3. A piezoelectric resonator having a piezoelectric substrate, a vibrating electrode opposed to the piezoelectric substrate, and a lead electrode connected to the vibrating electrode, and at least main portions of both main surfaces of the piezoelectric substrate. A vibrating electrode covering layer formed of a thermosetting resin, wherein the vibrating electrode covering layer has a recess at least on a vibrating region of the piezoelectric resonant element. 4. The piezoelectric resonance component according to claim 3, wherein a flat sealing plate is provided on each of the vibrating electrode coating layers. 5. A piezoelectric resonance element having a piezoelectric substrate, a vibrating electrode opposed to the piezoelectric substrate, and a lead electrode connected to the vibrating electrode is prepared, and a heat is applied so as to cover both main surfaces of the piezoelectric substrate. A resin forming step of forming a curable resin, a resin curing step of curing the thermosetting resin after the resin forming step, and the thermosetting on the vibration region of the piezoelectric resonance element after the resin curing step Forming a recess by partially removing a conductive resin. 6. The method according to claim 5, further comprising, after the recess forming step, a sealing plate bonding step of bonding a sealing plate on the thermosetting resin.