JPH0766663A - Chip type piezoelectric resonator and manufacture thereof - Google Patents

Abstract

PURPOSE:To prevent a pinhole from being formed in the outer facing reign of the chip type piezoelectric resonator which enables surface mounting and is faced with the resin. CONSTITUTION:A mother board 21 having plural piezoelectric resonators 29 formed on a piezoelectric substrate 22 is prepared and an adhesive layer 8 is formed except in a vibration area while covering the respective main surfaces of the mother board 21; and mother sheets 4 and 5 having plural cover sheets 2 and 3 formed are arranged covering both the main surfaces of the motor board 21, and consequently a cavity for a vibration space is formed. Then the facing resin is applied and then the mother board 21 is divided to obtain plural chip type piezoelectric resonators. Therefore, even if the air in the cavity expands at the time of the setting of the adhesive layer, the layer is not broken and no air enters the facing resin even at the time of the setting.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip type piezoelectric resonator used as, for example, a chip type filter, an oscillator, a discriminator and the like, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Piezoelectric resonators conventionally used as filters, oscillators, and discriminators have generally been leads.

However, in recent years, surface mounting technology (SMD) has been adopted in order to miniaturize electronic devices, and along with this, this type of piezoelectric resonator also has a chip type without a lead wire. Is required.

[0004]

[Related Application] In order to meet the above-mentioned demand, the applicant of the present application filed a patent application directed to "chip type piezoelectric resonator and its manufacturing method" on October 19, 1992.
Filed as No. 280008. In this earlier application, a chip-type piezoelectric resonator and a method for manufacturing the same are proposed as described below.

FIG. 14 is a perspective view showing the external appearance of the chip-type piezoelectric resonator 20 proposed in this earlier application.
The piezoelectric resonator 20 is obtained through the steps shown in FIGS. 6 to 13, respectively.

First, as shown in FIG. 6, a mother substrate 21
Is prepared. A part of this mother substrate 21 is enlarged and shown in FIG. The mother substrate 21 is provided with a piezoelectric substrate 22 made of piezoelectric ceramic. Divided vibrating electrodes 23 and 24 are formed on one main surface of the piezoelectric substrate 22, and these vibrating electrodes 23 and 24 are formed on the other main surface. The vibrating electrode 25 is formed so as to face the. Vibrating electrode 2
3, 24 and 25 have terminal electrodes 26, 2 respectively.
7 and 28 are connected. These one set of vibrating electrodes 23
25 to 25 and the terminal electrodes 26 to 28 constitute one piezoelectric resonance element 29, and the mother substrate 21 provides a plurality of piezoelectric resonance elements 29.

The piezoelectric resonance element 29 is composed of the divided vibrating electrodes 23 and 24 and the vibrating electrode 25 facing them.
Is a dual-mode piezoelectric resonator of energy trapping type that utilizes the thickness longitudinal vibration mode, and the following treatment is performed to secure the vibration space.

First, bank-shaped adhesive layers 30a and 30b are formed so as to surround the respective vibration regions of the piezoelectric resonance element 29.
Are formed on each main surface of the mother substrate 21 by printing, for example.

On the other hand, the above-mentioned adhesive layers 30a and 30
Mother sheets 43 and 4 having a plurality of cover sheets 41 and 42 respectively covering the space surrounded by b
4 is prepared. These mother sheets 43 and 44
Preferably has an insulating property and is made of, for example, a high heat resistant polyimide sheet. Mother sheet 4
In each of 3 and 44, the plurality of cover sheets 41 and 42 are preferably held by connecting portions 45 and 46 that are narrower than the cover sheets 41 and 42. Also, these mother sheets 43 and 4
It is preferable that 4 has the same external dimensions as the mother substrate 21.

Mother sheets 43 and 4 as described above
4 is arranged so as to cover each main surface of the mother substrate 21 so that the cover sheets 41 and 42 are adhered to the adhesive layers 30a and 30b. At this time, as described above, if the outer dimensions of the mother sheets 43 and 44 are made equal to the outer dimension of the mother substrate 21, the alignment between the mother sheets 43 and 44 and the mother substrate 21 can be performed. It's easy.

On the other hand, as shown in FIG. 8, a frame 31 made of, for example, resin is prepared in which the above-mentioned mother board 21 can be fitted almost exactly. This frame 31 has a temperature (for example, 150 ° C.) at the time of heat curing of the exterior resin described later.
It is taken into consideration that it does not deform or melt. Further, when the outer side surface 32 of the frame 31 is used as a reference plane for cutting, which will be described later, it is desirable that the flatness is good.

Further, it is preferable to provide the frame 31 with means for fixing the mother substrate 21 to be inserted therein at substantially the center of the frame 31 in the thickness direction. In this example,
The shelves 33 are provided inside the opposite sides (for example, short sides) of the frame 31.

As shown in FIG. 9, the mother substrate 21 covered with the above-mentioned mother sheets 43 and 44 is fitted into the frame 31, and in that state, as shown in FIG. The uncured exterior resin 34 is poured. As the exterior resin 34, for example, an epoxy thermosetting resin liquefied by a solvent is used. The exterior resin 34 is dried by, for example, natural drying, and after the exterior resin 34 does not flow out even if the frame 31 is inverted together with the mother substrate 21, the frame 31 is inverted together with the mother substrate 21 and the exterior resin 34. Then, on the other surface of the mother substrate 21, again, the exterior resin 34
Is poured. The exterior resin 34 is also naturally dried, for example.

As described above, instead of inserting the already stacked mother sheets 43 and 44 and the mother substrate 21 into the frame 31, the frame 31 is used as a guide for aligning each other. , Frame 31
First, either one of the mother sheets 43 or 44
May be inserted, then the mother board 21 may be inserted, and either the other mother sheet 44 or 43 may be further inserted.

Then, the exterior resin 34 poured in two steps as described above is, for example, at 150 ° C. for 30 minutes,
Heat cured. As described above, since the cover sheets 41 and 42 are held by the relatively thin connecting portions 45 and 46, when the exterior resin 34 is poured,
These connecting portions 45 and 46 hardly hinder the flow of the exterior resin 34, and the exterior resin 34 can sufficiently wrap around the gap between each of the connecting portions 45 and 46 and the mother substrate 21.

Next, in order to improve the dimensional accuracy and flatness in the thickness direction of the chip-type piezoelectric resonator 20 (FIG. 14) to be obtained, the outer surface of each exterior resin 34 is polished together with the frame 31. This polishing is performed by lapping using a polishing plate, for example. As a result, FIG.
A sandwich structure 35 in which both surfaces of the mother substrate 21 are covered with the exterior resin 34 is obtained as shown in FIG.

Next, as shown in FIG. 11, this sandwich structure 35, together with the frame 31, is located on the outside surface 3 of the frame 31.
2 is taken as a reference plane and cut along the cutting lines 36 and 37. By this cutting, the mother substrate 21 is divided into individual piezoelectric resonance elements 29, and the terminal electrodes 26
~ 28 is exposed on the cut surface. In this way, the chip 47 as shown in FIGS. 12 and 13 is obtained.

As shown in FIG. 13, cover sheets 41 and 42 are disposed on adhesive layers 30a and 30b, respectively, thereby adhesive layers 30a and 30.
cavities 48 and 49 with thicknesses corresponding to the respective thicknesses of b
Are formed in association with the vibration region of the piezoelectric resonance element 29.

The steps of polishing and cutting described above are
It may be implemented with the sandwich structure 35 taken out from the frame 31.

Next, as shown in FIG. 14, the terminal electrode 26
External electrodes 3 so as to be electrically connected to each of
8-40 are formed on the outer surface of the tip 47. These external electrodes 38 to 40 are formed by, for example, dry plating such as sputtering or vacuum evaporation, or printing and baking of a conductive paste. Note that each of the external electrodes 38 to 40 may be formed only on one side surface of the chip 47 where the terminal electrodes 26 to 28 are exposed.

[0021]

In the chip type piezoelectric resonator 20 described in the above-mentioned related application, the cavities 48 and 49 are respectively secured as shown in FIG.
The adhesive that provides each of the adhesive layers 30a and 30b is
For example, it is printed with a thickness of about 30 μm to about 40 μm. Further, since the cover sheets 41 and 42 are bonded to the adhesive layers 30a and 30b, a high temperature is applied, and the adhesive is hardened.

However, as described above, when the adhesive is cured, a high temperature is applied, so that the cavity 48 is formed.
And the air in 49 expands and the adhesive layers 30a and 3
May break through 0b. As a result, the adhesive layer 30a
And holes may be formed in 30b.

Thereafter, as described above, the exterior resin 34 is applied and cured by heating. At this time, the cavity 48 is also provided.
And the air in 49 expands. This expanded air is
The adhesive layers 30 a and 30 b may pass through the holes formed undesirably and enter the exterior resin 34, and as a result, pinholes may be generated in the exterior resin 34. Figure 15
As shown in FIG. 4, such pinholes 50 often appear in the cut surface, and the resulting chip-type piezoelectric resonator 20 is obtained.
In the case, the appearance is deteriorated.

Therefore, it is an object of the present invention to provide a chip type piezoelectric resonator and a manufacturing method thereof, which can solve the problems caused by the expansion of air in the cavity as described above.

[0025]

The chip-type piezoelectric resonator according to the present invention, like the chip-type piezoelectric resonator described in the above-mentioned related application, has a piezoelectric substrate, a vibrating electrode facing the piezoelectric substrate, and A piezoelectric resonance element including a terminal electrode connected to each of them is formed, and a cavity is formed in the vibration area of the piezoelectric resonance element. Therefore, between the adhesive layer formed on each main surface of the piezoelectric substrate and the vibration area. A cover sheet disposed on each adhesive layer so as to form a cavity having a thickness corresponding to the thickness of the adhesive layer, and further, an exterior resin covering both main surfaces of the piezoelectric substrate via the cover sheet. I have it.

According to the present invention, in order to solve the above-mentioned technical problem, the adhesive layer is formed so as to cover each main surface of the piezoelectric substrate except at least the vibration region of the piezoelectric resonance element. A cover sheet is arranged on each of the adhesive layers.

Further, the method of manufacturing the chip type piezoelectric resonator according to the present invention includes the following steps, like the one described in the above-mentioned related application. That is, first,
A mother substrate is prepared in which a plurality of piezoelectric resonance elements including a vibrating electrode facing each other with the piezoelectric substrate sandwiched therebetween and terminal electrodes connected to the vibrating electrodes are formed on the piezoelectric substrate. Next, an adhesive layer is formed on each main surface of the mother substrate except at least the vibration region of each piezoelectric resonance element. On the other hand, a mother sheet having a plurality of cover sheets respectively covering the respective vibration regions of the piezoelectric resonance element is prepared. The mother sheets are arranged so as to cover the main surfaces of the mother substrate, so that the cover sheets are adhered to the adhesive layers. Then, a thermosetting exterior resin is applied so as to cover both main surfaces of the mother substrate. Next, the mother substrate covered with the exterior resin is divided into individual piezoelectric resonance elements so that the terminal electrodes are exposed on the division surfaces, and a plurality of chip-type piezoelectric resonators are obtained.

In the method of manufacturing a chip-type piezoelectric resonator as described above, in the present invention, in order to solve the above-mentioned technical problem, the adhesive layer is formed on the mother substrate except at least the vibration region of each piezoelectric resonance element. It is characterized in that it is formed so as to cover each main surface, and that the mother sheet is arranged so as to cover each main surface of the mother substrate so that the cover sheet is bonded to such an adhesive layer.

[0029]

In the present invention, the adhesive layer is basically formed over almost the entire surface so as to cover each main surface of the piezoelectric substrate or the mother substrate, and the cover sheet is adhered to such adhesive layer. Therefore, even if the air in the cavity between the vibrating region and the cover sheet expands due to the high temperature applied when the adhesive that provides the adhesive layer is about to be cured, this expanded air causes the adhesive layer to expand. It is possible to prevent breakthrough.
In other words, the adhesive layer has a sufficient adhesive area to withstand the expansion of air in the cavity.

[0030]

Therefore, according to the present invention, since no hole is formed in the cured adhesive layer, the air in the cavity is removed when the exterior resin applied thereon is heat-cured. When inflated, this air can remain within the cavity. Therefore, it is possible to prevent air from entering the exterior resin, thereby causing pinholes in the exterior resin. As a result, the problem of poor appearance due to pinholes is solved, and the production yield of the chip-type piezoelectric resonator is improved, whereby the cost of the chip-type piezoelectric resonator can be reduced.

Further, the present invention, as described below,
The effects of the invention described in the above-mentioned related application are substantially retained.

That is, according to the chip type piezoelectric resonator of the present invention, since the cavity for the vibration space is formed by the adhesive layer and the cover sheet, the cavity can be formed in an accurate shape. Therefore, the height of the cavity can be made uniform, and as a result, the height of the piezoelectric resonator can be lowered without any problem.

On the other hand, in the method of manufacturing a piezoelectric resonator according to the present invention, the adhesive layer is formed in a state of being aligned with the vibration regions of the plurality of piezoelectric resonance elements provided by the mother substrate, and then the cover sheet. After the mother sheet is arranged so as to cover each main surface of the mother substrate so that is bonded to the adhesive layer, the exterior resin is applied. Therefore, after confirming that the cavity is properly aligned with the vibrating region, the exterior resin is applied, so that it is possible to prevent the piezoelectric resonator in which the cavity is formed at an improper position from being manufactured. .

Further, according to the manufacturing method of the present invention, since the mother substrate covered with the exterior resin is finally divided to obtain a plurality of chip type piezoelectric resonators, a large number of chip type piezoelectric resonators can be obtained. You can get it efficiently. Here, as described above, since the cavities are always surely formed in an appropriate state, a part of the cavities is not exposed due to the division, so that the manufacturing yield can be improved.

As a method of forming the above-mentioned cavity for the vibration space, a cavity forming material such as wax is applied to the vibration region of the piezoelectric substrate, and then a thermosetting exterior resin is applied, and this exterior is provided. When the resin is cured, there is a method in which the cavity forming material is transferred into the exterior resin, and as a result, a cavity for the vibration space is formed. However, with this method, it is difficult to obtain high accuracy in the area and shape of the cavity forming material. Also, when wax is used as the cavity forming material, the wax is absorbed in the exterior resin, so if the external electrode is formed by sputtering or vapor deposition under high temperature conditions, the internal wax becomes a gas and May interfere with formation.

According to the present invention, the cavity can be formed without using the cavity forming material such as the above wax. Therefore, the problems caused by the wax as described above can be advantageously solved. That is, as described above, since it is not necessary to consider the problem that the wax in the exterior resin becomes gaseous and hinders the formation of the external electrode, the external electrode can be formed without problems by sputtering or vapor deposition under high temperature conditions. While being able to
When a conductive paste is used as the external electrodes, the baking temperature is not limited, so that, for example, a conductive paste having a high baking temperature but excellent solderability can be used without any problem.

[0037]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 5 are for explaining one embodiment of the present invention. Of these drawings, FIG.
Corresponds to FIG. 6 described above, FIG. 2 corresponds to FIG.
FIG. 3 corresponds to FIG. 14. In the following description, similar reference numerals are used for corresponding elements, and redundant description may be omitted.

In order to obtain the chip type piezoelectric resonator 1 shown in FIG. 3, a mother substrate 21 is first prepared as shown in FIG. The mother board 21 has substantially the same configuration as the mother board 21 shown in FIGS. 6 and 7.

On the other hand, a plurality of cover sheets respectively covering the vibration regions of the plurality of piezoelectric resonance elements 29 provided by the mother substrate 21, that is, the regions where the vibration electrodes 23 to 25 (see also FIG. 7) are formed. 2 and 3
Mother sheets 4 and 5 integrally formed with are prepared. These mother sheets 4 and 5 preferably have an insulating property and are made of, for example, a high heat resistant polyimide sheet. The mother sheets 4 and 5 are said to form the plurality of cover sheets 2 and 3, respectively, because the mother sheets 4 and 5 are respectively formed as the plurality of cover sheets 2 as a result of the cutting step described later.
This is because it is divided into 3 and 3.

Each of the plurality of cover sheets 2 formed on the mother sheet 4 has a cutout portion 6 corresponding to the position of the terminal electrodes 26 and 27. On the other hand, mother sheet 5
Each of the plurality of cover sheets 3 formed in 1 has the cutout portion 7 corresponding to the position of the terminal electrode 28 (see FIG. 7).

Adhesive layers 8 and 9 (see also FIGS. 2 to 5) are formed so as to cover the main surfaces of the mother substrate 21 described above. One adhesive layer 8 is formed, for example, by printing in a hatched region in FIG. 1, that is, a region other than the vibration region and the regions where the terminal electrodes 26 and 27 are formed. The other adhesive layer 9 is also formed in a region other than the region where the vibration region and the terminal electrode 28 are formed,
For example, it is formed by printing. Each of these adhesive layers 8 and 9 is made of a thermosetting adhesive and has a thickness of, for example, about 30 μm to about 40 μm.

Mother sheets 4 and 5 as described above
Is arranged so as to cover each main surface of the mother substrate 21 so as to be adhered to the adhesive layers 8 and 9, and in this state, the adhesive that provides the adhesive layers 8 and 9 is heat-cured. At this time, even if the air in the cavities 10 and 11 (see FIG. 5) formed between the vibrating region and the cover sheets 2 and 3 expands, the adhesive areas of the adhesive layers 8 and 9 are sufficiently large. Due to the large size, the adhesive layers 8 and 9 are not pierced. As shown in FIG. 1, the mother sheet 4
If the outer dimensions of 5 and 5 are made equal to the outer dimension of the mother substrate 21, it is easy to perform alignment between the mother sheets 4 and 5 and the mother substrate 21.

On the other hand, the frame 31 as shown in FIG. 8 is prepared, and as shown in FIG. 9, the mother substrate 21 covered with the mother sheets 4 and 5 is fitted into the frame 31. In that state, similarly to the case shown in FIG. 10 described above, the uncured exterior resin 34 is formed on one surface of the mother substrate 21.
Is poured. Then, after the exterior resin 31 does not flow out even if the frame 31 is inverted together with the mother substrate 21, the frame 31 is inverted together with the mother substrate 21 and the exterior resin 34, and in this state, on the other surface of the mother substrate 21. Then, the exterior resin 34 is poured again.

As described above, instead of inserting the already stacked mother sheets 4 and 5 and the mother substrate 21 into the frame 31, the frame 31 is used as a guide for aligning each other. First, insert one of the mother sheets 4 or 5 into the frame 31,
Next, the mother board 21 may be inserted, and then the other mother sheet 5 or 4 may be inserted.

Next, the exterior resin 34 poured in two steps as described above is heat-cured. Then, as in the case of the above-mentioned related application, in order to improve the dimensional accuracy in the thickness direction and the flatness of the chip-type piezoelectric resonator 1 (FIG. 3) to be obtained, the outer surface of each of the exterior resins 34 is formed by the frame 31 Is polished with. As a result, the one corresponding to the sandwich structure 35 shown in FIG. 11 is obtained.

Next, as shown in FIG. 11, this sandwich structure 35 is used together with the frame 31 and the outer surface 3 of the frame 31.
2 is taken as a reference plane and cut along the cutting lines 36 and 37. By this cutting, the mother substrate 21 is divided into individual piezoelectric resonance elements 29, and the terminal electrodes 26
~ 28 is exposed on the cut surface. In this way, the chip 12 as shown in FIG. 2 is obtained.

The steps of polishing and cutting described above are
It may be implemented with the sandwich structure 35 taken out from the frame 31.

Next, as shown in FIGS. 3 to 5, external electrodes 38 to 40 are formed on the outer surface of the chip 12 so as to be electrically connected to the terminal electrodes 26 to 28, respectively. The external electrodes 38 to 40 can be formed by, for example, printing and baking a conductive paste, or dry plating such as sputtering or vacuum evaporation.

In this embodiment, the external electrodes 38-40 are
The chip 12 is formed to extend not only to one side surface where the terminal electrodes 26 to 28 are exposed, but also to the upper and lower surfaces and the other side surface. By doing so, when the chip-type piezoelectric resonator 1 is mounted on the circuit board, soldering thereof can be reliably achieved. In this case, the external electrode 38
The portions of 40 to 40 formed on the upper surface and / or the lower surface of the chip 12 may be formed in advance in the state of the sandwich structure 35 shown in FIG. 11. In addition, the external electrodes 38-40 are the terminal electrodes 26- of the chip 12.
28 may be formed only on the exposed one side surface.

As shown in FIG. 5, the cover sheets 2 and 3 are disposed on the adhesive layers 8 and 9, respectively, whereby a cavity 10 having a thickness corresponding to the thickness of each of the adhesive layers 8 and 9 is obtained. And 11 are formed in relation to the vibration area of the piezoelectric resonance element 29, that is, the area where the vibration electrodes 23 to 25 are formed.

Further, as shown in FIGS. 2 and 3, cross sections of the cover sheets 2 and 3 and the adhesive layers 8 and 9 appear on the outer surface of the chip 12 or the chip type piezoelectric resonator 1. If the colors of the cover sheets 2 and 3, that is, the mother sheets 4 and 5, and the colors of the adhesive layers 8 and 9 are the same as those of the exterior resin 34, the cross sections of the cover sheets 2 and 3 and the adhesive layers 8 and 9 will be described. Can be prevented from standing out on the outer surface of the chip 12 or the chip-type piezoelectric resonator 1.

Further, as shown in FIGS. 2, 4 and 5, the adhesive layers 8 and 9 are in contact with the terminal electrodes 26 and 27 and the terminal electrode 28, respectively, on the end face of the chip 12. Absent. This is because the adhesive layers 8 and 9 are formed so as not to cover the terminal electrodes 26 and 27 and the terminal electrode 28, respectively, as described above. Further, as for the cover sheets 2 and 3, as a result of the formation of the cutout portions 6 and 7 described above, the chip 1
On the end face of No. 2, it is not located near each of the terminal electrodes 26 and 27 and the terminal electrode 28. Such a configuration is effective as a measure for avoiding the following inconvenience. That is, mother sheets 4 and 5
And when the adhesive layers 8 and 9 have poor cuttability,
Often cover sheets 2 and 3 and adhesive layer 8
The edges of 9 and 9 may protrude from the end surface of the chip 12, and these edges may sag in the cutting direction. Such sagging causes the terminal electrodes 26-28 and the external electrodes 38-
Blocks conduction with 40. Therefore, as described above, the cover sheets 2 and 3 and the adhesive layers 8 and 9 are provided on the end surface of the chip 12 so that the terminal electrodes 26 to 2 are not formed.
If it is not located in the vicinity of 8, the terminal electrodes 26 to 28 and the external electrodes 38 to 40 can be well conducted regardless of the cuttability of the mother sheets 4 and 5 and the adhesive layers 8 and 9. it can. Mother sheet 4
If 5 and 5 and the adhesive layers 8 and 9 have excellent cuttability, such a measure is unnecessary.

Further, in the illustrated embodiment, the regions where the cutout portions 6 and 7 and the adhesive layers 8 and 9 having a shape corresponding to them are not formed in the cover sheets 2 and 3 are formed in a quadrangle. The shape is arbitrary, and may be, for example, a circular shape or an oval shape.

[Brief description of drawings]

FIG. 1 is a perspective view showing a mother substrate 21 and mother sheets 4 and 5 which are prepared to obtain a chip-type piezoelectric resonator 1 according to an embodiment of the present invention, separated from each other.

FIG. 2 is a perspective view showing an appearance of a chip 12 for obtaining the chip-type piezoelectric resonator 1 according to this embodiment.

FIG. 3 is a perspective view showing the external appearance of the chip-type piezoelectric resonator 1 according to this embodiment.

4 is an enlarged cross-sectional view taken along the line IV-IV in FIG.

5 is an enlarged cross-sectional view taken along the line VV of FIG.

FIG. 6 is a perspective view showing a mother substrate 21 and mother sheets 43 and 44, which are prepared to obtain a chip-type piezoelectric resonator 20 of interest to the present invention, separated from each other.

7 is an enlarged perspective view showing a part of the mother substrate 21 shown in FIG.

8 is a perspective view showing a frame 31 used to obtain the chip-type piezoelectric resonator 20 shown in FIG.

9 is a perspective view showing a state in which the mother board 21 and mother sheets 43 and 44 shown in FIG. 6 are fitted into the frame 31 shown in FIG.

FIG. 10 is an exterior resin 3 on the mother substrate 21 shown in FIG.
It is a perspective view showing the state where 4 is poured.

11 is a perspective view for explaining a cutting process of a sandwich structure 35 obtained after curing the exterior resin 34 shown in FIG.

12 is a perspective view showing the appearance of a chip 47 obtained by the cutting step shown in FIG.

13 is a cross-sectional view taken along the line XIII-XIII in FIG.

FIG. 14 shows the chip 47 shown in FIG.
It is a perspective view which shows the state which formed 40.

FIG. 15 is a view corresponding to FIG. 14 for explaining a problem encountered in the chip-type piezoelectric resonator 20 described with reference to FIGS. 6 to 14;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 chip type piezoelectric resonator 2,3 cover sheet 4,5 mother sheet 6,7 lacking part 8,9 adhesive layer 10,11 cavity 12 chip 21 mother substrate 22 piezoelectric substrate 23-25 vibration electrode 26-28 terminal electrode 29 Piezoelectric resonance element 34 Exterior resin 36, 37 Cutting line 38-40 External electrode

Claims (4)

[Claims] 1. A piezoelectric resonance element including a piezoelectric substrate, a vibration electrode facing each other with the piezoelectric substrate sandwiched therebetween, and a terminal electrode connected to each of the vibration electrodes, each main part of the piezoelectric substrate except at least a vibration region of the piezoelectric resonance element. An adhesive layer formed so as to cover each surface, and a cover sheet arranged on each adhesive layer so as to form a cavity having a thickness corresponding to the thickness of the adhesive layer between the adhesive layer and the vibration region. And an exterior resin covering both main surfaces of the piezoelectric substrate via the cover sheet,
Chip type piezoelectric resonator. 2. The chip-type piezoelectric element according to claim 1, wherein the adhesive layer is formed so as not to cover the terminal electrodes, and the cover sheet has cutout portions corresponding to the positions of the terminal electrodes. Resonator. 3. A mother substrate on which a plurality of piezoelectric resonant elements each including a vibrating electrode facing each other with the piezoelectric substrate sandwiched therebetween and terminal electrodes connected to the vibrating electrodes are prepared, and each of the piezoelectric resonant elements is provided. An adhesive layer is formed so as to cover each main surface of the mother substrate except at least the vibration area, and a plurality of covers that respectively cover the vibration areas of the piezoelectric resonance element and are bonded to each of the adhesive layers. A mother sheet having a sheet formed is prepared, and each mother sheet is arranged so as to cover each main surface of the mother substrate so that each cover sheet is bonded to each adhesive layer, and then, the mother substrate A thermosetting exterior resin is applied so as to cover both main surfaces, and then the mother substrate covered with the exterior resin is individually separated so that the terminal electrodes are exposed on the divided surfaces. Serial and divided into the piezoelectric resonant element to obtain a plurality of chip-type piezoelectric resonator, comprising the steps, the production method of the chip-type piezoelectric resonator. 4. In the step of forming the adhesive layer,
The adhesive layer is formed so as not to cover the terminal electrodes, and in the step of preparing the mother sheet,
The method for manufacturing a chip-type piezoelectric resonator according to claim 3, wherein a cutout portion is formed on the plurality of cover sheets corresponding to the position of the terminal electrode.