JP2808049B2 - Piezoelectric vibrating element and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric vibrating element used for an IC, for example, a tuning fork-shaped or rectangular-shaped piezoelectric vibrating element and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, for example, a piezoelectric vibration element as shown in FIG. 9 has been known. The piezoelectric vibrating element includes a plate-shaped piezoelectric substrate 1 made of piezoelectric ceramic, and a concave groove 2 formed on one surface of the piezoelectric substrate 1.
And the vibrating electrodes 3 and 4 respectively formed on two main surfaces (front and back) of the piezoelectric substrate 1. In manufacturing such a vibrating element, a notch is formed in a block made of a piezoelectric ceramic (not shown), and after cutting into a flake shape or further cutting into a predetermined shape, the vibrating electrodes 3 and 4 are formed. It is performed by a method of forming by vacuum evaporation, sputtering, printing, baking, or the like of a conductive paste. And the vibration electrodes 3 and 4 of the piezoelectric vibration element
A sealing plate 5 is laminated and adhered to the front and back surfaces of the piezoelectric substrate 1 so as to form a vibration space on each of the surface portions, and a predetermined external electrode or the like is formed to manufacture a piezoelectric resonator.

[0003]

The above-mentioned piezoelectric vibrating element has a problem that it is small, thin and complicated to handle, and stress is easily concentrated on the bottom of the concave groove so that it is difficult to handle. In addition, even in the above manufacturing method, the processing is complicated because it is small, thin, and easily broken.
There are problems that it is difficult to obtain hermeticity, the productivity is poor, and the reliability of product quality is poor.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has a piezoelectric vibrating element which improves work efficiency, improves productivity and reduces costs, and increases product reliability. And a method for producing the same.

[0005]

For this purpose, the present invention relates to a piezoelectric block made of piezoelectric ceramics.
A step of forming a plurality of grooves, a step of bonding a sealing plate to a surface on which the grooves are formed to cover the openings of the grooves, and a sealing plate covering the openings of the grooves. A step of cutting the adhesive block and a step of forming the required vibration electrode and lead electrode patterns on the main surface of the cut plate-shaped piezoelectric substrate with the opening of the groove closed by the sealing plate. It is characterized by.

[0006]

In the method of manufacturing a piezoelectric vibrating element according to the present invention, a plurality of grooves are formed in a piezoelectric block, and a sealing plate is adhered to a surface on which the grooves are formed to open the grooves. The ends are sealed to form a sealing plate adhesive block, and then the thin piezoelectric substrate is cut. After that, use the same method as before.
On the main surface of the piezoelectric substrate, required patterns of the vibrating electrode and the extraction electrode are formed. Therefore, since the opening end of the groove formed in at least one side of the piezoelectric substrate cut into a thin plate is formed in a hole by joining the sealing plate, the piezoelectric substrate which has been thinned and reduced in size is not provided with the groove. It is not processed in the state with. Since it has a shape with a hole that surrounds the periphery from the time of cutting, it is difficult to break, it is easy to handle afterwards, processing is easy, productivity is improved, sealing is improved, and products are Reliability is also improved.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing an example of a piezoelectric vibrating element according to the present invention. Elements corresponding to the conventional example will be described with the same reference numerals. The piezoelectric vibrating element includes a piezoelectric substrate 1 made of piezoelectric ceramics, a concave groove 2 formed on one side of the piezoelectric substrate 1, and a sealing plate 6 adhered to cover an opening forming the concave groove 2. Of the piezoelectric substrate 1
Vibration electrode 3 and extraction electrode 7 formed on main surface (front side)
And a vibrating electrode 4 and an extraction electrode 8 formed on the other second main surface (back side).

In this embodiment, the piezoelectric substrate 1 has a thin plate shape, two concave grooves 2 are formed in one side in parallel, two openings are formed, and the legs 9a, 9b, 9c are formed. It has an E-shape. The vibrating electrode 3 on the front side of the piezoelectric substrate 1 is formed at the center of a strip-shaped leg 9a at the center, and is connected to an extraction electrode 7 formed from the tip to the sealing plate 6. The rear vibrating electrode 4 is formed at a position facing the front vibrating electrode 3, and is connected to a lead electrode 8 formed on the bottom side of the groove on the opposite side that does not face the front lead electrode 7. Then, an equivalent circuit having the configuration shown in FIG. 2 is formed.

The electrodes 3, 4, 7, and 8 are formed on the piezoelectric substrate 1 or the sealing plate 6 made of piezoelectric ceramics by vacuum deposition, sputtering, or printing and baking a conductive paste. The sealing plate 6 can be made of an appropriate material such as an insulator such as alumina, a dielectric such as barium titanate, and a conductor such as copper.

FIG. 3 is a plan view showing another example of the piezoelectric vibrating element according to the present invention. Elements corresponding to the above-described example will be described with the same reference numerals. In the piezoelectric substrate 10 made of the piezoelectric ceramic of the present embodiment, two concave grooves 2 deep from one side are formed in parallel, and the central one 9a of the three legs forming the concave grooves 2 is short. A groove 11 is formed to be shallow at the tip of the leg. Similarly to the above embodiment, a sealing plate 6 is adhered to the side of the opening formed by the concave groove 2 to cover the opening. On the front side of the piezoelectric substrate 10 covered with the sealing plate 6, a vibration electrode 12
a, 12b, 13 and an extraction electrode 14 are formed.

The vibrating electrode 12a extends along the side wall of the center leg 9a on the groove 2 side, from the tip of the leg 9a to the bottom of the groove 2, and along the side wall of the leg 9b. Is formed so as to be connected to the extraction electrode 14 formed in the above. The vibration electrode 12b is also formed similarly symmetrically to the vibration electrode 12a. The vibrating electrode 1 between these vibrating electrodes 12a and 12b
Reference numeral 3 is formed to extend from the front end of the center of the leg 9a to the center of the side on the bottom side with the groove 11 of the center leg 9a interposed therebetween. Then, a circuit having the configuration shown in FIG. 4 is formed.

Next, a method of manufacturing the above-described piezoelectric vibrating element will be described with reference to FIGS. Piezoelectric block 15 made of piezoelectric ceramics as shown in FIG.
In addition, as shown in FIG. 6A, a required number of concave grooves 2, 2,.
With a dicing saw or the like. Then, FIG.
As shown in (b), the sealing plate 6 is laminated and bonded to the surface where the concave grooves 2,... Are formed, and covers the openings of the concave grooves 2,. I do. And the sealing plate 6
Then, the sealing plate adhesive block in which the openings of the concave grooves 2,... Of the piezoelectric block 15 are covered is cut to a predetermined thickness along the line BB by a cutter blade or a laser. Subsequently, if necessary, the substrate is cut along the line CC.
Further, a required pattern of the vibrating electrodes 3 and 4 and the extraction electrodes 7 and 8 (not shown) is formed to form a piezoelectric vibrating element.

In order to obtain a piezoelectric resonator or the like from the piezoelectric vibration element, as shown in FIG. 7, the surface side of the piezoelectric substrate 1 is made of an insulating material such as alumina so as to form a vibration space on the surface of the vibration electrode 3. A sealing substrate 5 made of a material such as alumina is laminated and adhered, and a sealing substrate 5 made of an insulating material such as alumina is similarly laminated and adhered on the back side. In order to form a vibration space on the surface portion of the vibration electrode 3 or 4, a sealing substrate or an adhesive having a recess formed so as to form a gap is applied with a certain thickness, laminated, and adhered. Next, an external electrode is formed to obtain a piezoelectric resonator composed of a single or a plurality of vibration electrodes.

As shown in FIG. 8A, a groove 11 is formed to form a piezoelectric block 15 in addition to the grooves 2, 2 shown in FIG. 6A. Next, FIG.
As shown by, the sealing plate 6 is laminated and bonded to form a sealing plate bonding block in which the sealing plate 6 is bonded to the piezoelectric block 15 and the opening end of the concave groove 11 is covered. The sealing plate adhesive block is cut to a predetermined thickness along the DD line and the EE line by a cutter blade, a laser, or the like. Other steps are the same as the steps shown in FIGS. 6 and 7, and thus the description is omitted.

As described above, since the opening of the concave groove of the piezoelectric block is covered with the sealing plate and cut into thin pieces,
The workability is improved, the productivity is improved, and the stress concentration at the corners of the groove can be reduced and cracking can be prevented, so that the reliability of the product can be improved. The sealing plate 6 and the sealing substrate 5 may be hard or flexible, and may be, for example, a heat-resistant film, a ceramic plate, a ceramic sheet, or the like. Further, the order of the cutting step is not limited to the above embodiment, and may be changed as appropriate.

[0016]

As described above, according to the present invention, the stress is concentrated on the bottom of the groove before processing it into the plate-shaped piezoelectric substrate by covering the plurality of grooves with the sealing plate. To prevent cracking and improve the work efficiency compared to the conventional method of manufacturing a piezoelectric vibrating element, improve mass productivity and reduce costs, and improve product reliability. .

[Brief description of the drawings]

FIG. 1 is a plan view of one embodiment of a piezoelectric vibrating element according to the present invention.

FIG. 2 is an equivalent circuit diagram of the present embodiment.

FIG. 3 is a plan view of another embodiment of the piezoelectric vibrating element according to the present invention.

FIG. 4 is an equivalent circuit diagram of the present embodiment.

FIG. 5 is a perspective view showing a piezoelectric block used for manufacturing the piezoelectric vibration element according to the present invention.

6A and 6B are diagrams illustrating a part of the steps of an embodiment of the manufacturing method of the present invention, wherein FIG. 6A is a perspective view of a state where a piezoelectric block is processed, and FIG. It is a perspective view explaining the process of FIG.

FIG. 7 is an exploded perspective view illustrating an example of a process for manufacturing a piezoelectric resonator from the piezoelectric vibration element according to the present invention.

8A and 8B are diagrams illustrating a part of the steps of another embodiment of the manufacturing method of the present invention, wherein FIG. 8A is a perspective view showing a state where a piezoelectric block is processed, and FIG. It is a perspective view explaining a previous process.

FIG. 9 is an exploded perspective view illustrating a manufacturing process of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piezoelectric substrate 2 Groove 3,4 Vibration electrode 5 Sealing substrate 6 Sealing plate 7,8 Extraction electrode

Claims (1)

(57) [Claims] 1. A step of forming a plurality of grooves in a piezoelectric block made of piezoelectric ceramics, and a step of bonding a sealing plate to a surface on which the grooves are formed to cover an opening of the groove. When,
A step of cutting the sealing plate adhesive block in which the opening of the groove is covered; and a step of closing the opening of the groove with the sealing plate, and forming a required vibration electrode on the main surface of the cut plate-shaped piezoelectric substrate. And forming a pattern of an extraction electrode.