JP2002190629A - Method for manufacturing piezoelectric element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a piezoelectric element in which a substrate of piezoelectric material having high planarity and parallelism can be formed without having any adverse effect on the resonance characteristics thereof. SOLUTION: The method for manufacturing a piezoelectric element comprises a step for making trenches 1a on the surface of a reinforcing plate 1, and a step for bonding the reinforcing plate 1 to a quartz plate (a substrate of piezoelectric material) 2 by introducing an adhesive having fluidity into the trenches 1a of the reinforcing plate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a piezoelectric element, and more particularly, to a method for manufacturing a piezoelectric element by processing a substrate made of a piezoelectric material with a reinforcing plate attached to the substrate made of the piezoelectric material. About the method.

[0002]

2. Description of the Related Art In recent years, as the amount of information in electronic devices has increased and the speed has increased, the oscillation frequency and clock frequency of electronic devices have been required to be higher. So, for example,
Quartz crystal resonator, which is an example of a piezoelectric element made of a piezoelectric material,
It is required to have a fundamental resonance frequency of 100 MHz or more.

Here, in the case of a thickness-sliding quartz crystal resonator, the resonance frequency is determined by the thickness. For this reason, in order for the quartz plate to have a fundamental resonance frequency of 100 MHz or more, it is necessary to reduce the thickness of the quartz plate to 20 μm or less. In this case, there is an inconvenience that the thin quartz plate is easily damaged.

Conventionally, in order to prevent the above-mentioned inconveniences, a method has been adopted in which a quartz plate is processed to a predetermined thickness with a reinforcing plate attached to the quartz plate via an adhesive. More specifically, first, an adhesive is applied to the bonding surface of the reinforcing plate, and then the crystal plate and the reinforcing plate are bonded by bonding the crystal plate to the bonding surface of the reinforcing plate to which the adhesive has been applied. I was Then, the quartz plate was polished to a predetermined thickness in a state where the reinforcing plate was attached and reinforced.

[0005]

However, in the above-described conventional method, the adhesive applied to the joint surface of the reinforcing plate usually has poor fluidity, and therefore, it is difficult to spread the adhesive uniformly on the joint surface of the reinforcing plate. There was an inconvenience. Therefore, it has been difficult to form a uniform adhesive layer on the joint surface between the reinforcing plate and the quartz plate. As described above, if the adhesive layer on the joining surface between the quartz plate and the reinforcing plate is not formed uniformly, the surface of the quartz plate is polished by a predetermined thickness in a state where the reinforcing plate and the quartz plate are joined. In addition, there is a problem that the flatness and parallelism of the quartz plate are reduced. Therefore, it is difficult to form a quartz plate having high flatness and parallelism by the above-described conventional method.

In view of the above, in Japanese Patent Application Laid-Open No. 8-46475, a quartz plate is physically bonded to the surface of a silicon plate as a reinforcing plate using intermolecular force without using an adhesive, and then the quartz plate is There has been proposed a technique for polishing the surface to about 15 μm. Since the proposed technique does not use an adhesive, it is considered possible to prevent the flatness and the parallelism of the quartz plate from lowering due to the non-uniformity of the adhesive layer.

However, in this proposed technique,
Since the silicon plate and the quartz plate are physically bonded using intermolecular force, when the silicon plate is peeled off from the quartz plate after processing, a physical stress is applied to the quartz plate. For this reason, there is a problem that the resonance characteristics of the quartz plate may change. In addition, when an intermolecular force is used, there is no bonding strength enough to withstand polishing of a desired thickness, and thus there is a problem that a quartz plate having high parallelism and flatness cannot be formed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a high parallelism substrate without changing the resonance characteristics of a substrate (quartz plate) made of a piezoelectric material. An object of the present invention is to provide a method for manufacturing a piezoelectric element capable of forming a substrate made of a piezoelectric material having a degree and a degree of flatness.

Another object of the present invention is to provide a method of manufacturing a piezoelectric element which can easily form a thin and uniform adhesive layer between a reinforcing plate and a substrate made of a piezoelectric material. It is.

Still another object of the present invention is to join a reinforcing plate and a substrate made of a piezoelectric material in a state in which there is substantially no adhesive layer on a joining surface between the reinforcing plate and the substrate made of a piezoelectric material. It is to provide a possible method of manufacturing a piezoelectric element.

[0011]

According to a first aspect of the present invention, there is provided a method of manufacturing a piezoelectric element, comprising the steps of forming a concave portion on a surface of a reinforcing plate, and introducing a fluid adhesive into the concave portion of the reinforcing plate. Bonding the plate and a substrate made of a piezoelectric material. Incidentally, the recess in the present invention,
This is a concept including a groove-shaped concave portion, a concave portion in a minute uneven shape, and the like.

According to the first aspect, as described above, the concave portion is formed in the reinforcing plate, and the adhesive having fluidity is introduced into the concave portion, so that the reinforcing plate and the substrate made of the piezoelectric material have a predetermined strength. Can be joined. And
By polishing a substrate made of a piezoelectric material bonded to a reinforcing plate with such an adhesive, a substrate made of a piezoelectric material having high parallelism and flatness can be formed. Also, since the adhesive layer can be easily dissolved by an organic solvent or the like, the adhesive layer must be dissolved even when the reinforcing plate is peeled off from the substrate made of the piezoelectric material after processing the substrate made of the piezoelectric material. Thereby, the reinforcing plate can be peeled off without applying a physical force to the substrate made of the piezoelectric material. Thus, it is possible to effectively prevent the resonance characteristic of the substrate made of the piezoelectric material from being changed. As described above, according to the first aspect of the present invention, it is possible to form a substrate made of a piezoelectric material having high parallelism and flatness without changing the resonance characteristics of the substrate made of the piezoelectric material.

According to a second aspect of the present invention, in the method of the first aspect, the step of bonding the reinforcing plate and the substrate made of the piezoelectric material includes bonding the reinforcing plate and the substrate made of the piezoelectric material together. The method includes a step of joining the reinforcing plate and the substrate made of a piezoelectric material by introducing a flowable adhesive from the recess in a pressed state. In the second aspect, the bonding surface of the reinforcing plate and the piezoelectric material are formed by introducing a fluid adhesive in a state where the reinforcing plate and the substrate made of the piezoelectric material are bonded and pressed. In a state where the joining surfaces of the substrates are in contact with each other, the adhesive having fluidity permeates the joining surfaces. Thereby, a thin and uniform adhesive layer can be easily formed between the reinforcing plate and the substrate made of the piezoelectric material.

According to a third aspect of the present invention, in the configuration of the first or second aspect, the concave portion of the reinforcing plate extends at least to an end of a joint portion between the reinforcing plate and a substrate made of a piezoelectric material. Is formed. According to the third aspect, the recess of the reinforcing plate is formed so as to extend at least to the end of the joint between the reinforcing plate and the substrate made of the piezoelectric material, so that the reinforcing plate and the substrate made of the piezoelectric material are separated from each other. Even in the bonded state, the adhesive can be easily introduced from the concave portion at the end of the joint between the reinforcing plate and the substrate made of the piezoelectric material.

According to a fourth aspect of the present invention, in the method of any one of the first to third aspects, prior to the step of joining the substrate made of the piezoelectric material and the reinforcing plate, the joining surface of the reinforcing plate and the piezoelectric material are connected. Further comprising a step of mirror-finishing the bonding surface of the substrate made of According to the fourth aspect of the present invention, the bonding surface of the reinforcing plate and the bonding surface of the substrate made of the piezoelectric material are mirror-finished, so that the permeability of the adhesive at the bonding surface of the reinforcing plate and the substrate made of the piezoelectric material is reduced. As a result, the uniform adhesive layer can be easily formed on the joint surface between the reinforcing plate and the substrate made of the piezoelectric material. Furthermore, if both surfaces of the substrate made of the piezoelectric material are mirror-finished and the bonding surface of the reinforcing plate is mirror-finished, the bonding between the substrate made of the piezoelectric material and the reinforcing plate can be performed using an optical flat method (a method based on light interference). Interference fringes appearing on the surface can be observed. Thereby, the flatness of the substrate made of the piezoelectric material at the time of bonding can be measured. As a result, based on the measurement result, the flatness of the substrate made of the piezoelectric material at the time of bonding can be easily adjusted.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the reinforcing plate includes a material having a thermal expansion coefficient close to that of a substrate made of a piezoelectric material. According to the fifth aspect, the reinforcing plate is configured to include a material having a thermal expansion coefficient close to the thermal expansion coefficient of the substrate made of a piezoelectric material,
When a temperature change occurs, it is possible to effectively prevent generation of thermal stress at a bonding interface between the reinforcing plate and the substrate made of a piezoelectric material. Thus, it is possible to prevent a decrease in flatness due to generation of a strain between the reinforcing plate and the substrate made of the piezoelectric material.

According to a sixth aspect of the present invention, in the method of any one of the first to fifth aspects, after the step of joining the substrate made of the piezoelectric material and the reinforcing plate, the surface of the substrate made of the piezoelectric material is removed. Polishing a predetermined plate thickness,
Thereafter, a step of peeling the substrate made of the piezoelectric material from the reinforcing plate by dissolving the adhesive is further provided. According to the sixth aspect, by dissolving the adhesive, the substrate made of the piezoelectric material can be easily separated from the reinforcing plate without applying a physical force to the substrate made of the piezoelectric material. As a result, the substrate made of the piezoelectric material can be separated from the reinforcing plate without adversely affecting the resonance characteristics of the substrate made of the piezoelectric material.

According to a seventh aspect of the present invention, there is provided a method for manufacturing a piezoelectric element.
A step of forming a concave portion on the surface of the reinforcing plate and, in a state in which a substrate made of a piezoelectric material is bonded to the surface of the reinforcing plate, a thermosetting resin is applied from the side of the bonding surface between the reinforcing plate and the substrate made of the piezoelectric material By introducing the first adhesive and the second adhesive having fluidity from the concave portion of the reinforcing plate,
A step of joining the reinforcing plate and the substrate made of the piezoelectric material, and forming the piezoelectric material piece by cutting the substrate made of the piezoelectric material into a predetermined size in a state where the reinforcing plate and the substrate made of the piezoelectric material are joined. Dissolving the second adhesive having a flowability and the second adhesive without peeling off the reinforcing plate portion joined to the piezoelectric material piece via the first adhesive;
Removing only the reinforcing plate portion bonded to the piezoelectric material piece via the adhesive.

According to the seventh aspect of the present invention, a piezoelectric material piece in which the reinforcing plate portion is joined to a part of the surface can be easily formed. Thus, when the piezoelectric material piece is carried, the reinforcing plate portion can be held and easily carried. As a result, even when the size of the piezoelectric material piece is reduced, handling of the piezoelectric material piece can be easily performed.

[0020] The method of manufacturing a piezoelectric element according to claim 8 is as follows.
In the structure of the first aspect, the concave portion formed on the surface of the reinforcing plate includes pores formed on at least the joint surface of the reinforcing plate.

According to the eighth aspect, as described above, by forming pores as recesses on at least the joining surface of the reinforcing plate, if a flowable adhesive is introduced into the pores on the surface of the reinforcing plate, the pores can be formed. Can easily join the reinforcing plate and the substrate made of the piezoelectric material. In this case, since the adhesive is located in the pores on the surface of the reinforcing plate, the reinforcing plate and the substrate made of the piezoelectric material are separated from each other in a state where the bonding layer between the reinforcing plate and the substrate made of the piezoelectric material has substantially no adhesive layer. Can be joined. As a result, when the substrate made of the piezoelectric material bonded to the reinforcing plate is polished, the parallelism and the flatness of the substrate made of the piezoelectric material are reduced due to the variation in the thickness of the adhesive layer. Absent. As a result, a substrate made of a piezoelectric material having higher parallelism and higher flatness can be formed. Also, since the adhesive can be easily dissolved by an organic solvent or the like, even when the reinforcing plate is peeled off from the substrate made of the piezoelectric material after processing the substrate made of the piezoelectric material,
By dissolving the adhesive, the reinforcing plate can be peeled off without applying a physical force to the substrate made of the piezoelectric material. Thus, it is possible to effectively prevent the resonance characteristic of the substrate made of the piezoelectric material from being changed. Thus, according to the invention of claim 8, a substrate made of a piezoelectric material having higher parallelism and higher flatness can be formed without changing the resonance characteristics of the substrate made of a piezoelectric material.

According to a ninth aspect of the present invention, there is provided a method of manufacturing a piezoelectric element.
In the structure of claim 8, the reinforcing plate having pores includes a reinforcing plate made of porous ceramics. In claim 9,
Thus, by using the reinforcing plate made of porous ceramics, many pores exist on the surface of the reinforcing plate. Thus, if the adhesive is introduced into many of the pores, the reinforcing plate and the substrate made of the piezoelectric material can be easily separated from each other in a state where the adhesive layer is substantially absent on the joint surface between the reinforcing plate and the substrate made of the piezoelectric material. Can be joined.

According to a tenth aspect of the present invention, there is provided a piezoelectric element manufacturing method according to the ninth aspect, wherein the reinforcing plate made of porous ceramics is one selected from the group consisting of porous ferrite, porous alumina, and porous carbon. Includes a reinforcing plate made of a material. According to the tenth aspect, a commercially available material can be easily diverted as the reinforcing plate by using the above-mentioned conventional material as the reinforcing plate made of porous ceramics.

According to a eleventh aspect of the present invention, in the configuration of the tenth aspect, the step of forming the porous ferrite includes the step of sintering the ferrite compact and the step of finishing after sintering the ferrite compact. And a step of performing. According to the eleventh aspect, by using such a process, a porous ferrite can be easily formed.

According to a twelfth aspect of the present invention, in the method of the tenth or eleventh aspect, the density of the pores of the porous ferrite is 4000 / mm ² or more.
00 / mm ² or less. According to the twelfth aspect, by adopting such a configuration, it is possible to prevent a decrease in the adhesive strength and to prevent an adverse effect on the parallelism and flatness of the substrate made of the piezoelectric material. That is, the pore density of the porous ferrite is 400
If it is smaller than 0 / mm ² , the amount of the adhesive embedded in the pores also decreases due to the decrease in the number of pores. As a result, there is a disadvantage that the adhesive strength is reduced. Further, the pore density of the porous ferrite is 10,000
If the number exceeds the number of pores / mm ² , the number of pores increases and the pores become denser, so that the pores have the same diameter as the pores. Therefore, when a substrate made of a piezoelectric material bonded to a reinforcing plate is processed, there is a disadvantage that the parallelism and flatness of the substrate made of a piezoelectric material are reduced. According to claim 12, for preventing these disadvantages, the density of pores of the porous ferrite constitutes the 4000 / mm ² or more 10000 / mm ² or less.

According to a thirteenth aspect of the present invention, in the method of any of the tenth to twelfth aspects, the average pore diameter of the pores of the porous ferrite is 5 μm or less.
According to the thirteenth aspect, with such a configuration, it is possible to prevent the parallelism of the substrate made of the piezoelectric material from being adversely affected. That is, when the average pore diameter of the pores of the porous ferrite is larger than 5 μm, the portion of the substrate made of the piezoelectric material located on the pores of the reinforcing plate is deformed by the pressing force of the grindstone during polishing of the substrate made of the piezoelectric material. There are cases. In this case, there is a disadvantage that the parallelism of the substrate made of the piezoelectric material is reduced. In claim 13,
In order to prevent such inconvenience, the average pore diameter of the pores of the porous ferrite is set to 5 μm or less.

According to a fourteenth aspect of the present invention, there is provided a piezoelectric element manufacturing method comprising the steps of: forming a reinforcing plate having pores on at least a bonding surface; and introducing an adhesive into the pores of the reinforcing plate.
The method includes a step of bonding a substrate made of a piezoelectric material on the surface of the reinforcing plate, and a step of polishing the substrate made of the piezoelectric material bonded on the reinforcing plate.

According to the fourteenth aspect, as described above, by introducing the adhesive into the pores of the reinforcing plate, the reinforcing plate and the substrate made of a piezoelectric material are easily joined by the adhesive introduced into the pores. be able to. In this case, since the adhesive is located in the pores on the surface of the reinforcing plate, the reinforcing plate and the substrate made of the piezoelectric material are separated from each other in a state where the bonding layer between the reinforcing plate and the substrate made of the piezoelectric material has substantially no adhesive layer. Can be joined. As a result, when the substrate made of the piezoelectric material bonded to the reinforcing plate is polished, the parallelism and flatness of the substrate made of the piezoelectric material are reduced due to the variation in the thickness of the adhesive layer. Absent. As a result, a substrate made of a piezoelectric material having higher parallelism and higher flatness can be formed. In addition, since the adhesive can be easily dissolved by an organic solvent or the like, when the reinforcing plate is peeled off from the substrate made of the piezoelectric material after processing the substrate made of the piezoelectric material, the adhesive is dissolved by dissolving the adhesive.
The reinforcing plate can be peeled off without applying a physical force to the substrate made of the piezoelectric material. Thus, it is possible to effectively prevent the resonance characteristic of the substrate made of the piezoelectric material from being changed.

According to a fifteenth aspect of the present invention, in the construction of the fourteenth aspect, the step of introducing the adhesive includes the step of introducing the adhesive into the pores of the reinforcing plate and onto the surface of the reinforcing plate. And removing the adhesive in a portion other than the pores. According to the present invention, the adhesive can be easily embedded only in the pores of the reinforcing plate. Thereby, the reinforcing plate and the substrate made of the piezoelectric material can be bonded by the adhesive embedded in the pores in a state where the bonding layer between the reinforcing plate and the substrate made of the piezoelectric material has substantially no adhesive layer. .

According to a sixteenth aspect of the present invention, there is provided a method of manufacturing a piezoelectric element according to any one of the eighth to fifteenth aspects, wherein the reinforcing plate having pores has a size on which a plurality of substrates made of the piezoelectric material can be arranged. Having. According to the sixteenth aspect, by adopting such a configuration, a substrate made of a plurality of piezoelectric materials can be arranged on the reinforcing plate having pores, so that there is no need to use a mounting table. Accordingly, it is possible to eliminate a disadvantage that distortion occurs between the reinforcing plate and the mounting table due to heat generated when the reinforcing plate and the substrate made of the piezoelectric material are bonded. Also, there is no inconvenience that the flatness and the parallelism of the substrate made of the piezoelectric material are reduced by the strain generated between the substrate and the substrate. As a result, the flatness and parallelism of the substrate made of the piezoelectric material can be further improved.

According to a seventeenth aspect of the present invention, there is provided a method of manufacturing a piezoelectric element according to any one of the first to sixteenth aspects, wherein the substrate made of the piezoelectric material comprises quartz and langasite (La ₃ G).
a ₅ SiO ₁₄ ). In claim 17, by using a substrate made of such a piezoelectric material,
A piezoelectric element having excellent flatness and parallelism can be easily formed.

[0032]

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

(First Embodiment) FIGS. 1 to 9 are perspective views for explaining a manufacturing process of a quartz oscillator according to a first embodiment of the present invention. The manufacturing process of the crystal unit according to the first embodiment will be described below with reference to FIGS. In addition, the quartz oscillator is the “piezoelectric element” of the present invention.
This is an example.

First, as shown in FIG.
A 1 mm × 1 mm reinforcing plate 1 is prepared. This reinforcing plate 1
It is preferably formed of a material having a coefficient of thermal expansion close to the coefficient of thermal expansion of the quartz plate 2 described later. For example, in the present embodiment, the reinforcing plate 1 made of Al ₂ O ₃ —TiC is used.

Next, as shown in FIG. 2, a plurality of grooves 1a are formed on the joint surface of the reinforcing plate 1. This groove 1a has a thickness of 0.1
It is formed in a rectangular shape having a width of about mm and a depth of about 0.2 mm. The groove 1a extends to both ends of the reinforcing plate 1. The groove 1a is an example of the "recess" of the present invention.

Next, as shown in FIG.
A quartz plate 2 having a size of mm × 0.2 mm is prepared. The quartz plate 2 is an example of the “substrate made of a piezoelectric material” of the present invention. The front and back surfaces of the quartz plate 2 in this state are satin-like surfaces.

From this state, as shown in FIG. 4, both sides of the quartz plate 2 are mirror-polished, so that the thickness of the quartz plate 2 is reduced to 0.07 mm, and the front and back surfaces of the quartz plate 2 are mirror-finished. Finish. This mirror finishing is performed on the quartz plate 2
It is preferable to process the both surfaces so that the surface roughness Ra (center line average roughness) value is 0.003 μm or less. This is because the surface roughness of the quartz plate 2 is Ra value of 0.00.
If the thickness is 3 μm or more, it becomes difficult to obtain a desired resonance frequency, and it becomes difficult to form a uniform adhesive layer between the quartz plate 2 and the reinforcing plate 1.

Next, as shown in FIG. 5, a plurality (three in this embodiment) of reinforcing plates 1 are arranged on a disk-shaped mounting table 100. In this state, the surface of the reinforcing plate 1 is mirror-finished. The mirror finishing of the reinforcing plate 1 is preferably performed so that the surface roughness of the reinforcing plate 1 becomes 0.01 μm or less in Ra value. This is because the surface roughness of the bonding surface of the reinforcing plate 1 is R
If the value of a is 0.01 μm or more, the adhesive layer formed between the quartz plate 2 and the quartz plate 2 undulates (undulates), making it difficult to form a uniform adhesive layer. . On the other hand, when the surface roughness of the reinforcing plate 1 is 0.01 μm or less in Ra value, the permeability of the adhesive to the surface of the reinforcing plate 1 increases, so that the reinforcing plate 1 can easily be placed between the quartz plate 2 and the reinforcing plate 1. A uniform adhesive layer can be formed.

As described above, after the joining surface of the reinforcing plate 1 is mirror-finished, a quartz plate 2 having both surfaces mirror-finished is bonded to the joining surface of the reinforcing plate 1 as shown in FIG. Press. This pressurization applies a pressure of 20 × 10 ⁴ Pa
This is performed by pressing with a pressing force of ３０30 × 10 ⁴ Pa. In this state, a wax-based adhesive is injected from the groove 1a of the reinforcing plate 1 using a dispenser or the like. Then, in a state where the upper portion of the quartz plate 2 is pressurized by the above-described pressing force, about 1
Heat at 00 ° C. for about 12 hours.

As the wax-based adhesive, an adhesive having low viscosity and fluidity is used. In this embodiment, an adhesive obtained by dissolving phthalic glue (manufactured by Nikka Seiko) with acetone is used. More specifically, a phthalic glue having a concentration of 17% by mass in which phthalic glue and acetone are mixed at a mixing ratio of 1: 5 is used. Note that the concentration of the phthalic glue is preferably in the range of 15% by mass to 20% by mass. When the concentration of the phthalic glue is lower than 15% by mass, the components of the adhesive are reduced, and the adhesive strength is reduced. In addition, the concentration of the phthalic glue is 20% by mass.
If it is larger, the fluidity becomes poor, and therefore, there is a disadvantage that the adhesive is difficult to spread evenly. For this reason, the concentration of the phthalic glue is preferably set within a range of 15% by mass or more and 20% by mass or less.

Here, in the first embodiment, both surfaces of the quartz plate 2 are mirror-finished and the surface of the reinforcing plate 1 is mirror-finished. By the optical flat method, interference fringes appearing at the joint interface between the quartz plate 2 and the reinforcing plate 1 can be observed. Thereby, the flatness at the time of bonding the quartz plate 2 can be measured. As a result, based on the measurement result, it is possible to easily adjust the bonding state of the quartz plate 2 so as to have a high flatness. Note that the optical flat method refers to a method of displaying light interference fringes on a measurement surface and measuring flatness from the interference fringes.

After the joining step of the reinforcing plate 1 and the quartz plate 2 shown in FIG. 6, the surface of the quartz plate 2 is polished while the reinforcing plate 1 and the quartz plate 2 are joined as shown in FIG. Thereby, the thickness of the quartz plate 2 is processed to a thickness of 20 μm or less.
In this polishing step, first, FO # 3000 abrasive grains (particle diameter 3
６6 μm). After that, finish polishing is performed using cerium oxide abrasive grains (average primary particle size: 0.5 μm). During the polishing, the thickness of the quartz plate 2 is controlled by measuring the height from the upper surface of the reinforcing plate 1 to the upper surface of the quartz plate 2 using an electric micrometer or the like.

By this polishing, in the present embodiment, the quartz plate 2 having a high flatness and a high parallelism of 0.2 μm / 2 mm □ (PV value) or less and a parallelism of 0.1 μm / 4 mm or less in this embodiment. Can be formed. As a result, it is possible to form the quartz plate 2 having good resonance characteristics that does not generate sub-vibration.

Thereafter, as shown by a dashed line in FIG. 8, the quartz plate 2 is cut using, for example, a resin grindstone.
The quartz plate 2 is peeled from the reinforcing plate 1 by dissolving an adhesive (phthalic glue) between the reinforcing plate 1 and the quartz plate 2 with an organic solvent (acetone). Thus, a crystal blank 2a as shown in FIG. 9 is obtained. In addition, crystal piece 2
a is an example of the “piezoelectric material piece” of the present invention.

In the manufacturing process of the quartz resonator according to the first embodiment, as described above, the groove 1a is formed in the reinforcing plate 1 and the adhesive (1) having fluidity is formed from the groove 1a.
By injecting 7% by mass of phthalic glue), the adhesive having fluidity introduced from the groove 1a easily and uniformly penetrates into the joint surface between the reinforcing plate 1 and the quartz plate 2.
Thereby, the adhesive layer can be uniformly formed on the joint surface between the reinforcing plate 1 and the quartz plate 2. Then, the quartz plate bonded to the reinforcing plate with such a uniform adhesive layer is polished to a predetermined thickness, whereby a quartz plate having high parallelism and flatness can be formed.

Further, after cutting the quartz plate 2 to a predetermined size, the adhesive is dissolved, so that the quartz plate 2 can be easily separated from the reinforcing plate 1 without applying a physical force to the quartz plate 2. be able to. As a result, the quartz plate 2 can be separated from the reinforcing plate 1 without adversely affecting the resonance characteristics of the quartz plate 2.

Further, by bonding the reinforcing plate 1 and the quartz plate 2 together and introducing a flowable adhesive (17 mass% phthalic glue) in a pressurized state, the bonding surface of the reinforcing plate 1 is With the bonding surfaces of the crystal plate 2 in contact with each other,
Since an adhesive having fluidity is introduced to the joining surface,
A thin and uniform adhesive layer can be easily formed.

Further, in the first embodiment, the reinforcing plate 1
Is formed of a material (Al ₂ O ₃ —TiC) having a thermal expansion coefficient close to the thermal expansion coefficient of the quartz plate 2 so that when a temperature change occurs, heat is applied to the joint surface between the reinforcing plate 1 and the quartz plate 2. The generation of stress can be effectively prevented. Thereby, it is possible to prevent a decrease in flatness due to generation of distortion between the reinforcing plate 1 and the quartz plate 2.

(Second Embodiment) FIGS. 10 to 15 are a sectional view and a perspective view for explaining a manufacturing process of a quartz oscillator according to a second embodiment of the present invention. 10 to 1
5, the manufacturing process according to the second embodiment will be described below.

First, in the second embodiment, FIGS.
After going through the same process as the manufacturing process of the first embodiment shown in FIG. 10, the process shifts to the manufacturing process shown in FIG. FIG.
In the manufacturing process shown in FIG. 0, pressure is applied in a state where the quartz plate 12 is bonded to the joint surface of the reinforcing plate 11 provided with the plurality of grooves 11a. This pressurization is performed similarly to the first embodiment.
The top of the quartz plate ^{12 20 × 10 4 Pa~30 × 10} 4 Pa
This is performed by pressing with a pressing force of The groove 11a
Is an example of a “recess” of the present invention, and the quartz plate 12 is an example of a “substrate made of a piezoelectric material” of the present invention.

In this state, a thermosetting adhesive is injected from the side end of the joint surface between the reinforcing plate 11 and the quartz plate 12 in a direction perpendicular to the direction in which the groove 11a extends. Thereby, the thermosetting adhesive permeates the surface of the reinforcing plate portion 11c. As this thermosetting adhesive, for example, Able Bond (manufactured by Able Stick) is used. Thereafter, similarly to the manufacturing process of the first embodiment shown in FIG.
A wax-based adhesive (17 mass% phthalic glue) is injected from 1a. Thereby, the phthalic glue permeates the surface of the reinforcing plate portion 11b located between the grooves 11a. Then, heating is performed at about 100 ° C. for about 12 hours while the upper portion of the quartz plate 12 is pressurized by the above-described pressing force. Thereby, the quartz plate 12 is joined to the reinforcing plate 11.

Thereafter, as shown in FIG.
By polishing the upper surface of the
Process to the following thickness. The polishing conditions in this case are the same as in the first embodiment. Thereafter, as shown in FIG. 12, the quartz plate 12 is cut into a predetermined size.

Then, as shown in FIG.
Of the reinforcing plate 11 from the back side to the position indicated by the alternate long and short dash line. As a result, as shown in FIG. 14, the crystal blank 12a and the reinforcing plate portions 11b and 11c are separated.
By immersing the portion shown in FIG. 14 in acetone, the space between the crystal blank 12a and the reinforcing plate portion 11b and the groove 1
The wax-based adhesive (phthalic glue) located in 1a is dissolved. The crystal blank 12a and the reinforcing plate portion 1
1c does not dissolve in acetone. Thereby, only the reinforcing plate portion 11b can be peeled off from the crystal blank 12a. As a result, a shape in which only the reinforcing plate portion 11c is joined to a part of the surface of the crystal blank 12a is formed as shown in FIG. The quartz piece 12a is an example of the “piezoelectric material piece” of the present invention.

In the second embodiment, the crystal blank 12a in which the reinforcing plate portion 11c is joined to a part of the surface can be easily formed by the above manufacturing process. Thus, when carrying the crystal blank 12a, the reinforcing plate portion 11c can be held and easily carried. As a result, even when the crystal blank 12a is downsized,
a can be easily handled.

(Third Embodiment) FIGS. 16 to 24 are a perspective view and an enlarged sectional view for explaining a manufacturing process of a quartz oscillator according to a third embodiment of the present invention. FIG.
The manufacturing process of the third embodiment will be described below with reference to FIG.

In the manufacturing process of the third embodiment, the reinforcing plate 21 is formed of Mn-Z having many pores on its surface.
An n-type porous ferrite is used. As a method of forming the Mn-Zn porous ferrite, first, 65 to 75% by mass of FeO, 15 to 20% by mass of MnO,
Pure water and Aron are added to and mixed with 15% by mass of ZnO. Then, the mixture is calcined. This calcination is performed at about 850 ° C. to 900 ° C. for about 4 hours to 6 hours. afterwards,
Using a ball mill, calcine the mixture to about 1 μm to 3 μm.
crushed into fine particles of m. Then, a binder is added and dried to obtain a powder having good fluidity (granulation).
Further, a compressed body having a predetermined shape is formed by compacting with a press. And about 1200 ° C ~ 1300
Sintering at high temperature of ℃. Finally, the size and shape of the Mn—Zn-based porous ferrite are adjusted by performing finishing by polishing.

When forming ferrite with high density and few pores, usually, after sintering, the density is increased by HIP (Hot Isostatic Press). But,
In the third embodiment, since the purpose is to form porous ferrite having many pores, the densification processing by HIP is not performed.

After forming the reinforcing plate 21 made of Mn-Zn porous ferrite as described above, the reinforcing plate 21 is placed on the disk-shaped mounting table 100 as shown in FIG. In this state, the surface of the reinforcing plate 21 is mirror-finished.
The mirror finishing of the reinforcing plate 21 is preferably performed such that the surface roughness of the reinforcing plate 21 becomes 0.01 μm or less in Ra value, as in the first embodiment. When the cross section of the reinforcing plate 21 made of the Mn-Zn-based porous ferrite which has been mirror-finished in this way is enlarged and observed, a shape as shown in FIG. 17 is obtained. Referring to FIG. 17, a plurality of crystal grains 21 a are arranged on the surface of reinforcing plate 21. And
Pores 21b are formed between the crystal grains 21a.
The pores 21b are an example of the "recess" of the present invention.

The density of the pores 21b of the porous ferrite is preferably 4,000 / mm ² or more and 10,000 / mm ² or less. This is for the following reason. That is, when the density of the pores 21b of the porous ferrite is smaller than 4000 / mm ² , the amount of the adhesive embedded in the pores 21b also decreases due to the decrease in the number of the pores 21b. As a result, there is a disadvantage that the adhesive strength is reduced. When the density of the pores 21b of the porous ferrite exceeds 10,000 / mm ² , the number of the pores 21b increases and the pores 21b are densely packed, so that the flatness of the surface of the reinforcing plate 21 is reduced. For this reason, in the process described later, when the quartz plate 23 bonded on the reinforcing plate 21 is polished, there is a disadvantage that the parallelism and flatness of the quartz plate 23 are reduced. In the third embodiment, in order to prevent these inconveniences, the pore density of the porous ferrite is set to 40%.
It is preferable that the number be not less than 00 pieces / mm ^{2 and not} more than 10,000 pieces / mm ² .

The average surface diameter of the pores 21b of the porous ferrite is preferably 5 μm or less. This is for the following reason. That is, when the average pore diameter of the pores 21b of the porous ferrite is larger than 5 μm, in the process described later, when the quartz plate 23 is polished, the quartz plate 23 located on the pores 21b of the reinforcing plate 21 is pressed by the pressing force of the grindstone. May fall into the pores and deform. In this case, there is a disadvantage that the parallelism of the quartz plate 23 is reduced. To prevent such inconvenience,
In the embodiment, the average pore diameter of the pores 21b of the porous ferrite is preferably set to 5 μm or less.

After the mirror finishing of the reinforcing plate 21 shown in FIGS. 16 and 17, as shown in FIGS. 18 and 19, a wax-based adhesive 22 is applied on the joining surface of the reinforcing plate 21 by using a brush or the like. Apply. This wax-based adhesive 22
As in the first embodiment, an adhesive having low viscosity and fluidity is used. That is, a phthalic glue having a concentration of 17% by mass in which phthalic glue and acetone are mixed at a mixing ratio of 1: 5 is used. Highly fluid phthalic glue having such a concentration of 17% by mass (adhesive 22)
Is applied on the reinforcing plate 21. This adhesive 22 is used in FIG.
As shown in the figure, the reinforcing plate 21 is embedded in the pores 21b on the surface of the reinforcing plate 21 and is formed on the surface of the reinforcing plate 21 with a predetermined thickness.

It is to be noted that, after the adhesive 22 having fluidity and made of phthalic glue diluted with acetone is applied, the acetone component evaporates. Therefore, the adhesive 22 made of phthalic glue is in a solidified state.

After the adhesive 22 is solidified in this way, the adhesive 22 located on the surface of the reinforcing plate 21 is removed by polishing the adhesive 22. As a result, as shown in FIG. 20, the adhesive 22 is embedded only in the pores 21b on the surface of the reinforcing plate 21, and the adhesive 22 does not remain on the surface of the reinforcing plate 21 other than the pores 21b.

Thereafter, as shown in FIG.
A quartz plate 23, both sides of which are mirror-finished, is adhered to and bonded to the bonding surface of the above by pressing. The pressure bonding step, together with the upper portion of the quartz plate 23 is pressed with pressure of ^{20 × 10 4 Pa~30 × 10 4} Pa, carried out by heating at about 100 ° C. to about 3 to about 12 hours. As a result, the adhesive 22 embedded in the pores 21b on the surface of the reinforcing plate 21 becomes molten again, and the reinforcing plate 21 and the quartz plate 23 are joined by the adhesive 22. Here, the heating time is about 10
Preferably, it is about 12 hours. This is because bonding can be performed without generating distortion of the quartz plate due to a difference in the shrinkage ratio between the adhesive and the quartz plate. The quartz plate 23 is an example of the “substrate made of a piezoelectric material” of the present invention.

As described above, the quartz plate 23 is placed on the reinforcing plate 21.
Then, as shown in FIG. 22, the surface of the quartz plate 23 is polished while the reinforcing plate 21 and the quartz plate 23 are joined. Thus, the thickness of the quartz plate 23 is processed to a thickness of 20 μm or less. The polishing conditions in this step are the same as those in the first embodiment.

By this polishing, in the third embodiment, a quartz plate having high flatness and parallelism with a flatness of 0.2 μm / 2 mm □ (PV value) or less and a parallelism of 0.1 μm / 4 mm or less. 23 can be formed. Thereby, it is possible to form the quartz plate 23 having good resonance characteristics without generating the sub vibration.

Thereafter, as shown by the dashed line in FIG.
After cutting the quartz plate 23 using, for example, a resin grindstone, the adhesive (phthalic glue) embedded in the pores 21b between the reinforcing plate 21 and the quartz plate 23 is dissolved by an organic solvent (acetone). . Thereby, the quartz plate 23 is peeled off from the reinforcing plate 21. As a result, a crystal piece 23a as shown in FIG. 24 is obtained. The crystal piece 23a is an example of the “piezoelectric material piece” of the present invention.

In the third embodiment, as described above, by introducing the adhesive 22 into the pores 21b of the reinforcing plate 21, the adhesive 22 introduced into the pores 21b allows the reinforcing plate 21 and the quartz plate 23 to be in contact with each other. Can be easily joined. In this case, since the adhesive 22 is located only in the pores 21b, it is possible to join the reinforcing plate and the quartz plate in a state where the adhesive layer does not substantially exist on the joining surface between the reinforcing plate 21 and the quartz plate 23. it can. Thus, when the quartz plate 23 bonded on the reinforcing plate 21 is polished, the inconvenience that the parallelism and the flatness of the quartz plate decrease due to the variation in the thickness of the adhesive layer does not occur. As a result, the quartz plate 23 having higher parallelism and higher flatness can be formed.

In the third embodiment, an adhesive (phthalic glue) is used as in the first embodiment.
The crystal 22 can be easily dissolved by an organic solvent (acetone) or the like. Therefore, when the reinforcing plate 21 is peeled off from the crystal plate 23 after the processing of the crystal plate 23, the adhesive 22 is dissolved by dissolving the adhesive 22. The reinforcing plate 21 can be peeled off without applying any physical force to the plate 23. as a result,
It is possible to effectively prevent the resonance characteristic of the quartz plate 23 from changing.

In the third embodiment, the material efficiency of the quartz plate can be improved as compared with the first embodiment. That is, in the first embodiment, in the step shown in FIG. 7, when the quartz plate 2 bonded on the reinforcing plate 1 is polished, a portion of the quartz plate 2 located on the groove 1a may be deformed. For this reason, in the step shown in FIG. 8, when cutting the quartz plate 2, a portion other than the portion located on the groove 1a is used as the quartz piece 2a. On the other hand, in the third embodiment, since there is no groove in the reinforcing plate 21, when the crystal plate 23 is cut out in the step shown in FIG. 23, all parts are formed as crystal blanks 23 a (see FIG. 24). It can be used. As a result, in the manufacturing method of the third embodiment, the material efficiency of the quartz plate 23 can be improved as compared with the first embodiment.

In the third embodiment, after the adhesive (phthalic glue) is introduced into the pores 21 b of the reinforcing plate 21 and on the surface of the reinforcing plate 21, the adhesive is applied to portions of the reinforcing plate 21 other than the pores 21 b. By removing 22 by polishing, adhesive 22 can be easily embedded only in pores 21b of reinforcing plate 21. As a result, the reinforcing plate 2 does not substantially exist on the bonding surface between the reinforcing plate 21 and the quartz plate 23 by the adhesive embedded in the pores 21b.
1 and the quartz plate 23 can be joined.

In the third embodiment, the reinforcing plate 21 is kept in a state where the adhesive 22 is left only in the pores 21b of the reinforcing plate 21.
And the quartz plate 23 were bonded under pressure. in this case,
When the reinforcing plate 21 and the quartz plate 23 are bonded under pressure, the reinforcing plate 21
If there is a gap between the quartz plate and the quartz plate 23, the adhesive 22 in the pores 21b may seep out to the joint interface between the reinforcing plate 21 and the quartz plate 23. However, even if the adhesive 22 oozes out at the bonding interface, the ooze out of the adhesive 22
Has an extremely small thickness of 0.1 μm or less. Therefore, unlike the case where a thick adhesive layer is present at the joint interface between the reinforcing plate 21 and the quartz plate 23, there is no inconvenience that the parallelism and flatness of the processed quartz plate 23 are reduced. ,No problem.

It should be noted that the embodiment disclosed this time is an example in all respects and is not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description of the embodiments, and includes all modifications within the scope and meaning equivalent to the terms of the claims.

For example, in the first and second embodiments, Al ₂ O ₃ —TiC having a thermal expansion coefficient close to that of a quartz plate is used as the material of the reinforcing plate. The material is not limited to this, and other materials may be used as long as the material has a thermal expansion coefficient close to that of the quartz plate. For example, quartz, alumina, quartz glass and the like can be considered. Further, it is possible to use a material having a thermal expansion coefficient close to that of a quartz plate. For example, a Mn-Zn-based or Ni-Zn-based ferrite material may be used. Use of a ferrite material having high workability as described above has an advantage that the processing of the reinforcing plate is facilitated.

In the first to third embodiments, phthalic glue having a concentration of 17% by mass is used as the adhesive having fluidity. However, the present invention is not limited to this, and the adhesive having fluidity may be used. As long as the adhesive is used, the same effect can be obtained by using another adhesive. For example, Alcowax (manufactured by Nikka Seiko Co., Ltd.) can be used as it is without using a solvent. In addition, as the adhesive having fluidity used in the present invention, it is preferable to use an adhesive having a fluid viscosity of about 10 cp to 30 cp at 100 ° C.

In the first and second embodiments,
Although the groove of the reinforcing plate is formed in a rectangular shape, the present invention is not limited to this, and the same effect can be obtained even if the groove is V-shaped, U-shaped, or another shape. Furthermore, minute unevenness may be provided on the surface of the reinforcing plate, and the adhesive may be introduced from the recess. In the present invention, such grooves and concave portions having minute unevenness are collectively referred to as concave portions.

In the first and second embodiments,
Although the groove of the reinforcing plate is formed so as to extend to and penetrate both ends of the reinforcing plate, the present invention does not necessarily need to extend to and penetrate both ends of the reinforcing plate. That is, the groove of the reinforcing plate only needs to extend at least to the end of the joint between the reinforcing plate and the quartz plate. With this configuration, even when the reinforcing plate and the quartz plate are bonded together, the adhesive can be easily introduced from the concave portion at the end of the joint between the reinforcing plate and the quartz plate.

In the third embodiment, a Mn-Zn porous ferrite is used as the reinforcing plate 21, but the present invention is not limited to this, and a Ni-Zn porous ferrite may be used. The same effect can be obtained by using a porous ceramic other than the porous ferrite. For example, porous alumina or porous carbon may be used. The same effect can be obtained not only with porous ceramics but also with a reinforcing plate having pores on the joining surface.

In the third embodiment, after the adhesive having fluidity (17% by mass of phthalic glue) is applied to the surface of the reinforcing plate 21, the adhesive 22 other than the pores 21b is polished. By removing, the pores 21b
Although the adhesive 22 is left only in the inside, the present invention is not limited to this, and the adhesive 22 may be left in the pores 21b by a method other than applying and polishing the adhesive.

In the first to third embodiments, a quartz plate is used as an example of a substrate made of a piezoelectric material. However, the present invention is not limited to this. ₃ Ga ₅ SiO ₁₄ ), LT (LiTaO)
_A similar effect can be obtained by using a substrate made of a piezoelectric material such as ₃ : lithium tantalate or LN (LiNbO ₃ : lithium niobate).

That is, concave portions (grooves or pores) are formed in the reinforcing plate.
Is formed, and by introducing an adhesive having fluidity into the concave portion, the reinforcing plate and the substrate made of the piezoelectric material can be joined with a predetermined strength. Then, a substrate made of a piezoelectric material having high parallelism and flatness can be formed by polishing a substrate made of a piezoelectric material bonded to a reinforcing plate with such an adhesive. Also, since the adhesive layer can be easily dissolved by an organic solvent or the like, the adhesive layer must be dissolved even when the reinforcing plate is peeled off from the substrate made of the piezoelectric material after processing the substrate made of the piezoelectric material. Thereby, the reinforcing plate can be peeled off without applying a physical force to the substrate made of the piezoelectric material. Thus, it is possible to effectively prevent the resonance characteristic of the substrate made of the piezoelectric material from being changed. In this manner, a substrate made of a piezoelectric material having high parallelism and flatness can be formed without changing the resonance characteristics of the substrate made of the piezoelectric material.

In the first to third embodiments, the method of manufacturing a piezoelectric element has been described by taking an example of a method of manufacturing a vibrator. However, the present invention is not limited to this, and the present invention is not limited to this. Can be widely applied to the method of manufacturing.

In the third embodiment, as shown in FIGS. 16 to 21, after a plurality of reinforcing plates 21 having pores are arranged on a disk-shaped mounting table 100, the reinforcing plates 21 are disposed. Although the example in which the quartz plate 23 is bonded via an adhesive has been described above, the present invention is not limited to this. As a modification of the third embodiment, as shown in FIG. A large reinforcing plate 31 having pores of, for example, 60 mm × 60 mm × 7 mm is prepared, and the large reinforcing plate 31 is provided.
A plurality of (twelve in this modification) quartz plates (substrates made of a piezoelectric material) 23 may be bonded thereto via an adhesive. With this configuration, since the mounting table is not used, distortion occurs between the reinforcing plate and the mounting table due to heat generated when the reinforcing plate and the quartz plate (substrate made of a piezoelectric material) are bonded. Inconvenience can be eliminated. Thus, there is no inconvenience that the flatness and the parallelism of the quartz plate (substrate made of a piezoelectric material) are reduced by the distortion generated between the reinforcing plate and the mounting table. As a result, the flatness and parallelism of the quartz plate (substrate made of a piezoelectric material) 23 can be further improved.

[0084]

As described above, according to the present invention, by introducing a flowable adhesive into the concave portion formed in the reinforcing plate, the adhesive is bonded to the joint surface between the reinforcing plate and the substrate made of the piezoelectric material. The agent layer can be formed uniformly. Thus, by polishing a substrate made of a piezoelectric material bonded to a reinforcing plate with such a uniform adhesive layer, a substrate made of a piezoelectric material having high parallelism and flatness can be formed. Further, by dissolving the adhesive with an organic solvent or the like, the reinforcing plate can be peeled from the substrate made of the piezoelectric material without adversely affecting the resonance characteristics of the substrate made of the piezoelectric material. Further, since the crystal blank having the reinforcing plate portion joined to a part of the surface can be easily formed, the crystal blank can be easily carried while holding the reinforcing plate portion.

In addition, by introducing an adhesive into the pores of the reinforcing plate, the adhesive introduced into the pores causes substantially no adhesive layer on the bonding surface between the reinforcing plate and the substrate made of a piezoelectric material. Thus, the reinforcing plate and the substrate made of the piezoelectric material can be joined. Thus, a substrate made of a piezoelectric material having higher parallelism and higher flatness can be formed.

[Brief description of the drawings]

FIG. 1 is a perspective view for explaining a manufacturing process of a crystal unit according to a first embodiment of the present invention.

FIG. 2 is a perspective view for explaining a manufacturing process of the crystal unit according to the first embodiment of the present invention.

FIG. 3 is a perspective view for explaining a manufacturing process of the crystal unit according to the first embodiment of the present invention.

FIG. 4 is a perspective view for explaining a manufacturing process of the crystal unit according to the first embodiment of the present invention.

FIG. 5 is a perspective view for explaining the manufacturing process of the crystal unit according to the first embodiment of the present invention.

FIG. 6 is a perspective view for explaining the manufacturing process of the crystal unit according to the first embodiment of the present invention.

FIG. 7 is a perspective view for explaining the manufacturing process of the crystal unit according to the first embodiment of the present invention.

FIG. 8 is a perspective view for explaining the manufacturing process of the crystal unit according to the first embodiment of the present invention.

FIG. 9 is a perspective view for explaining the manufacturing process of the crystal unit according to the first embodiment of the present invention.

FIG. 10 is a cross-sectional view for explaining a manufacturing process of the crystal unit according to the second embodiment of the present invention.

FIG. 11 is a cross-sectional view for explaining the manufacturing process of the crystal unit according to the second embodiment of the present invention.

FIG. 12 is a cross-sectional view for explaining the manufacturing process of the crystal unit according to the second embodiment of the present invention.

FIG. 13 is a cross-sectional view for explaining the manufacturing process of the crystal unit according to the second embodiment of the present invention.

FIG. 14 is a cross-sectional view for explaining the manufacturing process of the crystal unit according to the second embodiment of the present invention.

FIG. 15 is a perspective view for explaining the manufacturing process of the crystal unit according to the second embodiment of the present invention.

FIG. 16 is a perspective view for explaining the manufacturing process of the crystal unit according to the third embodiment of the present invention.

17 is an enlarged sectional view of a reinforcing plate in the manufacturing process shown in FIG.

FIG. 18 is a perspective view for explaining the manufacturing process of the crystal unit according to the third embodiment of the present invention.

19 is an enlarged cross-sectional view of the reinforcing plate in the manufacturing process shown in FIG.

FIG. 20 is an enlarged cross-sectional view for explaining the manufacturing process of the crystal unit according to the third embodiment of the present invention.

FIG. 21 is a perspective view for explaining the manufacturing process of the crystal unit according to the third embodiment of the present invention.

FIG. 22 is a perspective view for explaining the manufacturing process of the crystal unit according to the third embodiment of the present invention.

FIG. 23 is a perspective view for explaining the manufacturing process of the crystal unit according to the third embodiment of the present invention.

FIG. 24 is a perspective view for explaining the manufacturing process of the crystal unit according to the third embodiment of the present invention.

FIG. 25 is a perspective view for explaining a manufacturing process of a crystal unit according to a modification of the third embodiment of the present invention.

[Explanation of symbols]

 1, 11, 21, 31 Reinforcement plate 1a, 11a Groove (recess) 2, 12, 23 Quartz plate (substrate made of piezoelectric material) 2a, 12a, 23a Quartz piece (piezoelectric material piece) 11b, 11c Reinforcement plate portion 21a Crystal Grains 21b Pores (recess) 22 Adhesive 100 Mounting table

Claims (17)

[Claims] A step of forming a concave portion on the surface of the reinforcing plate; and a step of joining the reinforcing plate and a substrate made of a piezoelectric material by introducing a flowable adhesive into the concave portion of the reinforcing plate. A method for manufacturing a piezoelectric element, comprising: 2. The step of joining the reinforcing plate and the substrate made of the piezoelectric material includes: bonding the reinforcing plate and the substrate made of the piezoelectric material to each other, and pressing the substrate so that the fluidity is reduced from the concave portion. The method for manufacturing a piezoelectric element according to claim 1, comprising a step of joining the reinforcing plate and the substrate made of the piezoelectric material by introducing an adhesive having the same. 3. The piezoelectric element according to claim 1, wherein the concave portion of the reinforcing plate extends at least to an end of a joining portion between the reinforcing plate and the substrate made of the piezoelectric material. Manufacturing method. 4. The method according to claim 1, further comprising, before the step of joining the substrate made of the piezoelectric material and the reinforcing plate, a step of mirror-finishing the joining surface of the reinforcing plate and the joining surface of the substrate made of the piezoelectric material, respectively. The method for manufacturing a piezoelectric element according to claim 1, further comprising: 5. The reinforcing plate includes a material having a thermal expansion coefficient close to a thermal expansion coefficient of a substrate made of the piezoelectric material.
A method for manufacturing the piezoelectric element according to claim 1. 6. After the step of joining the substrate made of the piezoelectric material and the reinforcing plate, polishing the surface of the substrate made of the piezoelectric material by a predetermined thickness, and then dissolving the adhesive. The method of manufacturing a piezoelectric element according to any one of claims 1 to 5, further comprising: removing a substrate made of the piezoelectric material from the reinforcing plate. 7. A step of forming a concave portion on a surface of a reinforcing plate, and a bonding surface of the reinforcing plate and a substrate made of the piezoelectric material in a state where a substrate made of a piezoelectric material is bonded to the surface of the reinforcing plate. The first thermosetting adhesive is introduced from the side of the second plate, and the second fluid having fluidity is formed from the concave portion of the reinforcing plate.
A step of joining the reinforcing plate and the substrate made of the piezoelectric material by introducing an adhesive; and a step of joining the substrate made of the piezoelectric material in a state where the reinforcing plate and the substrate made of the piezoelectric material are joined. Forming a piezoelectric material piece by cutting to a size of; and dissolving the second adhesive having fluidity, thereby reinforcing the piezoelectric material piece via the first adhesive. Peeling off only the reinforcing plate portion bonded to the piezoelectric material piece via the second adhesive without peeling the plate portion. 8. The method according to claim 1, wherein the concave portion formed on the surface of the reinforcing plate includes pores formed on at least a joint surface of the reinforcing plate. 9. The method according to claim 8, wherein the reinforcing plate having pores includes a reinforcing plate made of porous ceramics. 10. The piezoelectric plate according to claim 9, wherein the reinforcing plate made of porous ceramics includes a reinforcing plate made of one material selected from the group consisting of porous ferrite, porous alumina, and porous carbon. Device manufacturing method. 11. The piezoelectric element according to claim 10, wherein the step of forming the porous ferrite includes a step of sintering a ferrite molded body, and a step of finishing after sintering the ferrite molded body. Manufacturing method. 12. The pore density of the porous ferrite.
Is 4000 pieces / mm ^TwoMore than 10000 pieces / mm^TwoBelow
A method for manufacturing the piezoelectric element according to claim 10.
Law. 13. The method for manufacturing a piezoelectric element according to claim 10, wherein the average pore diameter of the pores of the porous ferrite is 5 μm or less. 14. A step of forming a reinforcing plate having pores on at least a joining surface; a step of introducing an adhesive into pores of the reinforcing plate; and bonding a substrate made of a piezoelectric material on the surface of the reinforcing plate. A method for manufacturing a piezoelectric element, comprising: a step of polishing a substrate made of a piezoelectric material adhered on the reinforcing plate. 15. The step of introducing the adhesive, the step of introducing the adhesive into the pores of the reinforcing plate and on the surface of the reinforcing plate, and then removing the adhesive in a portion other than the pores of the reinforcing plate. The method for manufacturing a piezoelectric element according to claim 14, comprising: 16. The piezoelectric element according to claim 8, wherein the reinforcing plate having the pores has a size such that a plurality of substrates made of the piezoelectric material can be arranged thereon. Method. 17. The method for manufacturing a piezoelectric element according to claim 1, wherein the substrate made of the piezoelectric material includes any of quartz and langasite (La ₃ Ga ₅ SiO ₁₄ ).