JPH04247708A - Manufacturing method of chip type piezoelectric resonator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a chip-type piezoelectric resonator, and more particularly to a method of manufacturing a chip-type piezoelectric resonator using a thickness-shear vibration mode.

0002

2. Description of the Related Art Conventionally, piezoelectric resonators utilizing the thickness shear vibration mode have been widely used in filters, ceramic discriminators, traps, and the like. In the case of this type of piezoelectric resonator, the periphery of the resonator element is generally molded with an elastic material such as silicone rubber in order to suppress spurious waves of the resonator element.

When the piezoelectric resonator is constructed as a chip component, a recess is provided in the insulating case, the resonator element is accommodated in the recess, and the electrodes of the element and the electrodes of the case are connected using a conductive adhesive or the like. After the connections are made, the recess is filled with an elastic body, and then a lid is adhered to the insulating case to create a sealed structure.

0004

[Problem to be Solved by the Invention] However, when manufacturing the chip-type piezoelectric resonator as described above, since the case is extremely small, it is extremely inefficient to fill the recesses of the case with elastic bodies one by one. bad. Furthermore, there is a problem in that the elastic body tends to protrude from the case during filling, and the protruding elastic body interposes at the bonding surface between the case and the lid, resulting in poor sealing. Therefore, the amount of silicone rubber filled must be strictly controlled, further deteriorating productivity.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for manufacturing a chip-type piezoelectric resonator that has extremely high productivity and can produce a highly reliable product with no protrusion of the elastic body.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the method for manufacturing a chip-type piezoelectric resonator of the present invention provides a method for manufacturing a chip-type piezoelectric resonator in which electrodes are continuously formed on both the front and back sides of a piezoelectric motherboard in a thickness shear vibration mode. a step of bonding a sealing motherboard having a continuous groove formed on the inner surface thereof corresponding to the vibrating electrode portion of the electrode, and a continuous cavity formed by the piezoelectric motherboard and the groove of the sealing motherboard. The piezoelectric motherboard and the sealing motherboard are cut into chips after solidifying the liquid elastic material. It is something that

[0007] Electrodes continuous in the longitudinal direction are formed on both the front and back surfaces of the piezoelectric motherboard in the thickness shear vibration mode. With this piezoelectric motherboard in between, sealing motherboards of substantially the same shape are adhered from both sides of the piezoelectric motherboard. On the inner surface of the sealing motherboard, that is, on the surface facing the piezoelectric motherboard, a groove corresponding to the vibrating electrode portion of the electrode is continuously formed in the longitudinal direction. Therefore,
When the sealing motherboard is bonded to both surfaces of the piezoelectric motherboard, a cavity continuous in the longitudinal direction is formed between the two. When a liquid elastic body such as silicone rubber is poured from one end of the cavity, the cavity is filled with the elastic body without any gaps. At this time, there is no problem even if the elastic body protrudes from the end of the cavity, and there is no need to strictly control the filling amount. After the elastic body has solidified, the integrated piezoelectric motherboard, sealing motherboard, and elastic body are cut at a constant width in the longitudinal direction and orthogonal direction, and each element is separated into chips, and at this time the elastic body has already solidified. Therefore, it does not protrude toward the cut surface at all.

[0008]

[Example] FIGS. 1 to 3 show an example of a completed chip-type piezoelectric resonator according to the present invention, in which 1 is a resonator element using an energy-trapped thickness-shear vibration mode;
5 is a first sealing plate, and 20 and 25 are second sealing plates.

The resonator element 1 includes a piezoelectric substrate 2 made of a rectangular thin piezoelectric ceramic plate, and an electrode 3 formed from one end of the surface of the piezoelectric substrate 2 to approximately 2/3 of the total length. , an electrode 4 formed from the other end side of the back surface of the piezoelectric substrate 2 to approximately ⅔ of the total length,
The piezoelectric substrate 2 is polarized in its plane direction (direction of arrow P). Therefore, when a voltage is applied between the electrodes 3 and 4, thickness shear vibration is excited in the portion of the piezoelectric substrate 2 sandwiched between the opposing vibrating electrode portions 3a and 4a of the electrodes 3 and 4.

The first sealing plates 10 and 15 are made of insulating plates having approximately the same shape as the piezoelectric substrate 2, and their inner surfaces, that is, the resonator elements 1
Concave grooves 11 and 16 are formed in the width direction on the opposing surface. Flat parts 12 and 1 at both ends of these sealing plates 10 and 15
7 is adhered to both the front and back surfaces of the resonator element 1, and presses and holds both ends of the resonator element 1 as shown in FIG. With the first sealing plates 10 and 15 adhered to both surfaces of the resonator element 1 in this manner, an elastic material such as silicone rubber is filled in the cavity formed between the grooves 11 and 16 and the resonator element 1. 30 is filled. As shown in FIG. 4, connection electrodes 40 and 41 are formed on both left and right sides of both ends of this chip component by vapor deposition or other methods, and these connection electrodes 40 and 41 and the electrodes formed on the piezoelectric substrate 2 3 and 4 are electrically connected to each other.

[0011] The second sealing plates 20, 25 are also the first sealing plates 10,
It is made of an insulating plate similar to 15, and is bonded to the integrated chip component as shown in FIG. 4 from both sides thereof with an adhesive 50 of a constant thickness. Therefore, the area around the resonator element 1 is completely sealed. At this time, since the adhesive 50 is applied in a frame shape around the inner surfaces of the second sealing plates 20 and 25, a vibration space 51 is created on both sides of the center of the resonator element 1 as shown in FIG. The vibration of the resonator element 1 is not damped more than necessary. For the piezoelectric resonator assembled as described above, external electrodes 60, 61 (
When the external electrodes 60, 61 are connected to the electrodes 3, 4 of the resonator element 1 via the connecting electrodes 40, 41, the final chip-type piezoelectric resonance get a child Note that in the final piezoelectric resonator structure, the external electrodes 60 and 61 may be formed not only around both ends but also on both end faces by a method such as vapor deposition. in this case,
The connection between the electrodes 3 and 4 and the external electrodes 60 and 61 becomes more reliable.

[0012] If plates having recesses on their inner surfaces are used as the second sealing plates 20 and 25, a vibration space can be easily obtained even if the adhesive 50 is thin. Furthermore, if a vibration space is not required, the second sealing plates 20 and 25 may be bonded together over the entire surface. Furthermore, as shown in FIG. 4, the finished product may be made without the second sealing plate.

A specific manufacturing method for obtaining the chip component shown in FIG. 4 will now be described with reference to FIGS. 5 to 7. As shown in FIG. 5, electrodes 3A and 4A are formed continuously in the longitudinal direction on the front and back surfaces of a piezoelectric motherboard 2A which has been polarized in the direction of arrow P in advance. The front electrode 3A is formed in approximately 2/3 of the area from one side edge of the piezoelectric motherboard 2A, and the back electrode 4A is formed in approximately 2/3 of the area from the other side edge. Sealing motherboards 10A and 15 with continuous grooves 11A and 16A formed on their inner surfaces with this piezoelectric motherboard 2A in between.
When A is bonded, the flat parts 12A and 17A on both sides of the sealing motherboards 10A and 15A are brought into close contact with the piezoelectric motherboard 2A, and as shown in FIG. Two hollow portions 31A and 32A are formed which penetrate in the direction. When a liquid elastic body 30A such as silicone rubber is poured into these cavities 31A and 32A, the elastic body 30A is filled into the cavities 31A and 32A without any gaps. At this time, there is no problem even if the liquid elastic body 30A somewhat protrudes from both ends of the cavities 31A and 32A. After solidifying the elastic body 30A, when the piezoelectric motherboard 2A and the sealing motherboards 10A and 15A are sliced into chips as shown in FIG. 7, the elastic body 30A is also cut at the same time, resulting in the chip component shown in FIG. get. At this time, since the elastic body 30 has already solidified, the elastic body 30
There is no risk of the material protruding toward the cut surface. Therefore, when bonding the second sealing plates 20, 25 to both sides of this chip component, the elastic body 30 is not interposed between the bonding surfaces of the first sealing plates 10, 15 and the second sealing plates 20, 25. , can prevent sealing defects.

FIGS. 8 and 9 show other embodiments of the present invention,
An example of a filter using a dual mode resonator is shown. In the figure, two pairs of vibrating electrodes 71, 7 are provided on the surface of a piezoelectric substrate 70.
2, 73, and 74 are formed, and an input terminal electrode 7 is formed at both ends of the surface and is electrically connected to the vibration electrode 71 through a thin conductive part.
5 and an output terminal electrode 76 that is electrically connected to the vibrating electrode 74 through a thin conductive portion. And the middle 2
The vibrating electrodes 72 and 73 are electrically connected to each other via a thin conductive portion. The vibrating electrode 7 is provided on the back surface of the piezoelectric substrate 70.
Wide grounding vibrating electrodes 77, 78 are formed opposite to 1, 72 and 73, 74, and a grounding terminal electrode 79 is formed in the center to be electrically connected to these vibrating electrodes 77, 78.

The input/output vibrating electrode 7 is mounted on the upper sealing plate 80.
Two grooves 81 corresponding to 1, 72 and 73, 74,
82 is formed, and the lower sealing plate 85 also has two grooves 86 and 8 corresponding to the grounding vibration electrodes 77 and 78, respectively.
7 is formed. Then, by bonding the sealing plates 80 and 85 to the front and back surfaces of the piezoelectric substrate 70, the grooves 81 and 8
A total of four cavities are formed between 2, 86, 87 and the piezoelectric substrate 70, and these cavities are filled with a liquid elastic material 90 such as silicone rubber. In this case as well, the cavity is filled with liquid elastic material while the sealing motherboard is adhered to the piezoelectric motherboard in the same manner as described above, and then the chip component shown in FIG. 8 is obtained by cutting into chips. . Therefore, the elastic body 90 does not protrude from the cut surface.

[0016] Electrodes 91, 92, and 93 are formed on both sides of this chip component at three locations, at both ends and in the center, and these electrodes are electrically connected to terminal electrodes 75, 76, and 79, respectively. Ru. Other sealing plates are bonded to both sides of the chip component as necessary. Of course, the resonator element used in the piezoelectric resonator of the present invention is not limited to the electrode shape as in the embodiment.

[0017]

As is clear from the above explanation, according to the present invention, a continuous cavity formed by a piezoelectric motherboard and a sealing motherboard is filled with a liquid elastic material, and after the elastic material solidifies, a chip is removed. Since the material was cut into shapes, the elastic body was also cut at the same time.
There is no fear that the elastic body will protrude to the cut surface side. Therefore, highly reliable products without the elastic body protruding can be produced in large quantities at once. Furthermore, when filling the above-mentioned cavity with the liquid elastic material, even if the elastic material slightly protrudes from the cavity, it will not affect the final product in any way, so there is no need to strictly control the filling amount, and productivity is improved. Very expensive.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a final chip-type piezoelectric resonator according to the present invention.

FIG. 2 is an exploded perspective view of the piezoelectric resonator shown in FIG. 1;

FIG. 3 is a sectional view taken along the line III-III in FIG. 1;

FIG. 4 is a perspective view of a resonator element and a sealing plate integrated into a chip.

FIG. 5 is an exploded perspective view of a piezoelectric motherboard and a sealing motherboard.

FIG. 6 is a perspective view of a piezoelectric motherboard and a sealing motherboard bonded together.

FIG. 7 is a perspective view showing a state in which the elastic material is filled and then cut into chips.

FIG. 8 is a perspective view of a chip component according to a second embodiment of the present invention.

9 is an exploded perspective view of the chip component shown in FIG. 8. FIG.

[Explanation of symbols]

1 Resonator element 2
Piezoelectric substrate 3, 4
Electrodes 3a, 4a Vibrating electrode parts 10, 15 First sealing plates 11, 16 Concave groove 2A Piezoelectric motherboard 10A, 15
A Sealing base plate 11A, 16A Concave groove 30A Elastic body 31A, 32A Cavity part

Claims (1)

[Claims] 1. A sealing motherboard, which has continuous grooves corresponding to the vibrating electrode portions of the electrodes formed on both the front and back surfaces of a piezoelectric motherboard in thickness-shear vibration mode, in which electrodes are continuously formed on both the front and back surfaces. a step of bonding the plates, a step of filling a continuous cavity formed by the piezoelectric motherboard and the groove of the sealing motherboard with a liquid elastic material, a step of solidifying the filled liquid elastic material, and a step of solidifying the filled liquid elastic material; A method for manufacturing a chip-type piezoelectric resonator, including the step of cutting a piezoelectric motherboard and a sealing motherboard into chips after solidifying a liquid elastic body.