JP2002299977A - Method for manufacturing piezoelectric vibrator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a piezoelectric device by which a piezoelectric body is made to a thin plate with high accuracy and a piezoelectric vibrator is easily made to high frequency. SOLUTION: This method for manufacturing a piezoelectric vibrator is provided with a process for joining a second thin plate-shaped piezoelectric substrate to a first thin plate-shaped piezoelectric substrate where through holes are formed by making a plurality of holes, a process for holding a pressing tool that is inserted from the through hole of the first thin plate-shaped piezoelectric substrate into the through hole of the first thin plate-shaped piezoelectric substrate, a process for making the second thin plate-shaped piezoelectric substrate to be a thin plate while united with the jig into one, a process for removing the tool when the thickness of the second thin plate-shaped piezoelectric substrate becomes desired thickness and etching the second thin plate-shaped piezoelectric substrate, a process for forming electrode parts on the front and rear faces of the part located at the through hole of the second thin plate-shaped piezoelectric substrate, and a process for cutting out the surrounding part of the through-hole into piezoelectric vibrating units.

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 an extremely thin vibrator (thin plate) for obtaining a high-frequency oscillation frequency using a piezoelectric material.

[0002]

2. Description of the Related Art Piezoelectric devices such as vibrators and filters used in mobile and information communication devices in recent years have been developed to meet the basic requirements of high frequency and wide band in combination with the miniaturization and digitalization of devices. It tends to be a specification.

In particular, in the field of mobile communications, the era of multiplex communication has arrived, for example, the density of communication networks has increased. On the other hand, in these high-density communication networks, there has been a demand for more efficient filtering and broadening of filter characteristics than before. Is desired.

In order to oscillate the high frequency as described above, it is indispensable to process the piezoelectric vibrator so as to have a small thickness, and a typical example of the conventional piezoelectric vibrator processing method is a polishing technique or an etching. At present, it is possible to cope with higher frequency and wider band by improving thinning technology such as technology.

[0005]

However, in a method in which a piezoelectric vibrator (for example, a crystal vibrator of an AT-cut plate) is subjected to thickness polishing using a double-side polishing machine (commonly called a lapping machine), the work to be processed is difficult. During the polishing process and during handling of the workpiece (when removing the workpiece during the polishing operation), the workpiece is cracked or chipped. In order to obtain a high-frequency vibrator, the thickness of the plate itself is extremely thin, and the external dimensions of the workpiece are very small, such as 2 mm square. Therefore, it is very difficult to handle even during the assembly process.

It is considered that the limit of the thickness processing in mass production processing using a general double-side polishing machine is about 100 μm. This limit value is extremely thick for processing a thickness of a quartz oscillator or the like aiming at a higher frequency, and the processing itself is very unstable even when compared with a numerical value of the thickness.

On the other hand, even if a part of the piezoelectric plate is to be etched by a chemical etching method (for example, using a hydrofluoric acid solution) to increase the frequency, defects in the material are selectively removed due to the crystal structure of the quartz oscillator. Due to the difficulty of uniform thickness control and the condition of the etching solution (such as the temperature and concentration of the solution during etching), etc., the etching process partially thins the crystal unit. At present, the thickness control is very unstable in the production process and quality maintenance.

The present invention has been made in view of the above-mentioned problems of the conventional method for manufacturing a piezoelectric device, and provides a method for manufacturing a piezoelectric device which makes it possible to make a piezoelectric body thinner with high precision and to easily increase the frequency of a piezoelectric vibrator. It is intended for.

[0009]

In order to solve the above-mentioned object, the present invention relates to a first thin-plate piezoelectric substrate formed with a plurality of holes and formed with through holes, and a second thin-plate piezoelectric substrate. Bonding, holding a holding jig from the through hole of the first thin piezoelectric substrate into the through hole of the first thin piezoelectric substrate, and a state integrated with the jig. Thinning the second thin piezoelectric substrate with
Removing the jig when the thickness of the thin plate-shaped piezoelectric substrate reaches a desired thickness, etching the second thin plate-shaped piezoelectric substrate, and a portion located in the through hole of the second thin plate-shaped piezoelectric substrate Forming an electrode portion on the front and back surfaces of the substrate, and cutting the periphery of the through hole in the unit of the through hole in a form in which the first thin plate piezoelectric substrate and the second thin plate piezoelectric substrate are integrated. And a method for producing a piezoelectric vibrator.

[0010] In short, the present invention provides a thin plate-like structure by joining piezoelectric substrates in a relatively thick substrate state, forming a through-hole in one substrate, and forming a vibrating plate as a piezoelectric vibrator. This also improves the ease of the processing step.

Therefore, according to the present invention, a piezoelectric vibrator is realized by bonding a substrate made of a material different from that of a piezoelectric (quartz material) substrate. In this case, the two members are joined by a frictional force between the joining surfaces, or an organic adhesive is used. As a material of the substrate different from the quartz material, a polymer material or ceramic is used.

According to the manufacturing method of the present invention, the method of manufacturing a high-frequency vibrator can be relatively simplified, and the generation of cracks and chips due to the thinning of the piezoelectric vibrator is reduced.
It is intended to achieve workability and quality maintenance in each step of the manufacturing process, and to improve and improve the yield.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In each drawing, the same reference numeral indicates the same object. FIG. 1 is a perspective view illustrating an outline of a method of manufacturing a piezoelectric vibrator according to the present invention.

In FIG. 1, reference numeral 1 denotes a first thin piezoelectric substrate, 2 denotes a second thin piezoelectric substrate, 4 denotes a through hole, 5 denotes a jig, and 6 denotes an electrode portion. The same effect can be obtained by using the thin plate substrate 3 instead of the above. A plurality of holes are formed in the first thin piezoelectric substrate 1 by mechanical processing or chemical etching to form through holes 4, and the second thin piezoelectric substrate 2 is joined and integrated with an organic adhesive. . In the present embodiment, at the time of bonding, the thickness of the second thin piezoelectric substrate 2 is 80 μm, and the thickness of the first thin piezoelectric substrate 1 (or the thin substrate 3) is 70 μm. The oscillation frequency is assumed to be 150 MHz.

At the time of processing, a jig 5 is inserted from the through hole 4 of the first thin plate-shaped piezoelectric substrate 1 and its tip (the length L is the plate of the first thin plate-shaped piezoelectric substrate 1 (or the thin plate-shaped substrate 3)). Thickness) will reach the second thin piezoelectric substrate 2. In this state, the thickness of the second thin piezoelectric substrate 2 itself is reduced to a desired thickness by polishing the back surface of the joint portion of the second thin piezoelectric substrate 2.

The first thin plate-shaped piezoelectric substrate 1 and the second thin plate-shaped piezoelectric substrate 2 are joined to form an integrated form.
By processing the thickness of only the second thin-plate piezoelectric substrate 2 to be thin, the vibrating portion (the second thin-plate piezoelectric substrate 2) of the piezoelectric vibrator is thin, and the other portion of the piezoelectric vibrator (the first thin-plate piezoelectric substrate 2) is formed. Since the piezoelectric substrate 1) has a sufficient thickness compared to the vibrating part,
A piezoelectric vibrator having strength and capable of vibrating a high frequency can be obtained.

As can be seen from FIG. 1, when the through hole 4 formed in the first thin plate-like piezoelectric substrate 1 is considered as a unit of one piezoelectric vibrator, a plurality of parts can be separated and separated around the through hole 4. A piezoelectric vibrator having a very high frequency can be easily obtained. FIG. 3 is a perspective view illustrating the manufacturing flow of the present invention.

According to the present invention, in order to obtain the above-described piezoelectric vibrator,
The following manufacturing method is characterized. FIG. 3A shows a process in which a plurality of holes are formed in the first thin plate-shaped piezoelectric substrate 1 to form through holes 4, and FIG. 3B shows a process in which a second thin plate is formed in the first thin plate-shaped piezoelectric substrate 1. FIG. 3 (c) shows a holding jig inserted from the through hole 4 of the first thin plate-shaped piezoelectric substrate 1 into the through hole 4 of the first thin plate-shaped piezoelectric substrate 1 in the step of joining the two piezoelectric plates 2. 3D, the second thin piezoelectric substrate 2 is integrated with the jig 5 and the second thin piezoelectric substrate 2 is thinned by, for example, a thickness polishing machine (lapping machine). FIG. 3E shows the second thin piezoelectric substrate 2.
In the step of removing the jig 5 and etching the second thin piezoelectric substrate 2 when the thickness of the substrate has reached a desired thickness, FIG.
FIG. 3F shows a step of forming electrode portions 6 on the front and back of a portion of the second thin piezoelectric substrate 2 located at the through hole 4.
(G) is a mode in which the first thin plate-shaped piezoelectric substrate 1 and the second thin plate-shaped piezoelectric substrate 2 are integrated, and includes a step of cutting the periphery of the through hole 4 in units of the through hole 4. By the manufacturing method described above, the piezoelectric vibrator shown in FIG. The piezoelectric vibrator is formed by cutting the peripheral portion of the through hole 4.
There may be more than one.

In the manufacturing flow chart of FIG. 3, a thin plate-like piezoelectric substrate is used for both the first and second substrates. However, since the first substrate constitutes a frame of the piezoelectric vibrator, the first thin plate-like piezoelectric substrate is used. Substrate 1
Instead, a thin plate-like substrate 3 (polymer material or ceramic material) may be used. In addition, in the present invention, when joining the thin plate-like piezoelectric substrates or joining the thin plate-like piezoelectric substrate and the thin plate-like substrate, the joining surface is mirror-finished, and the two joining surfaces are joined by a frictional force, or an organic adhesive is used. The through hole 4 formed in the first thin plate-shaped piezoelectric substrate 1 or the thin plate-shaped substrate 3 is formed by using a mechanical method or an etching method (dry or wet). Dry etching or wet etching is also used as an etching method for etching the second thin piezoelectric substrate 2 or the thin substrate 3. In addition, by etching the second thin plate-shaped piezoelectric substrate 2 or the thin plate-shaped substrate 3, it is possible to obtain an effect of removing distortion after polishing.

[0020]

As described above, according to the manufacturing method of the present invention, it is possible to stably manufacture a thin-plate piezoelectric vibrator capable of coping with a higher frequency and a wider band, so that the manufacturing yield and the quality can be improved. Can be realized.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating the concept of a piezoelectric vibrator according to the present invention.

FIG. 2 is a flowchart illustrating a manufacturing method of the present invention.

FIG. 3 is a perspective view illustrating a manufacturing flow of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st thin plate-shaped piezoelectric substrate 2 2nd thin plate-shaped piezoelectric substrate 3 thin plate-shaped substrate 4 through hole 5 jig 6 electrode part

Claims (8)

[Claims] 1. A step of bonding a thin-plate piezoelectric substrate to a thin-plate substrate formed with a plurality of holes and having a through-hole formed therein, and inserting the thin-plate substrate into the through-hole of the thin-plate substrate from the through-hole. Holding the holding jig, reducing the thickness of the thin piezoelectric substrate in a state where the jig is integrated with the jig, and removing the jig when the thickness of the thin piezoelectric substrate becomes a desired thickness. Removing, etching the thin-plate piezoelectric substrate, forming electrode portions on the front and back of a portion of the thin-plate piezoelectric substrate located at the through hole, and cutting the piezoelectric vibrator unit. A method for manufacturing a piezoelectric vibrator, comprising: 2. A step of joining a second thin plate-shaped piezoelectric substrate to a first thin plate-shaped piezoelectric substrate on which a plurality of holes have been formed to form through holes, and the through-holes of the first thin plate-shaped piezoelectric substrate. From
Holding a holding jig inserted into the through-hole of the first thin plate-shaped piezoelectric substrate, thinning the second thin plate-shaped piezoelectric substrate in a state integrated with the jig; Removing the jig when the thickness of the thin plate-shaped piezoelectric substrate reaches a desired thickness, etching the second thin plate-shaped piezoelectric substrate, and a portion located in the through hole of the second thin plate-shaped piezoelectric substrate A method for manufacturing a piezoelectric vibrator, comprising the steps of: forming an electrode portion on the front and back of the device; and cutting the piezoelectric vibrator into units. 3. The method according to claim 1, wherein the step of forming the through-hole is performed before the step of bonding the piezoelectric substrate. . 4. The method for manufacturing a piezoelectric vibrator according to claim 1, wherein the material of said thin plate-shaped piezoelectric substrate is a quartz piezoelectric material substrate. 5. The method according to claim 2, wherein the material of the thin plate-shaped substrate is a polymer material or ceramic. 6. The piezoelectric vibrator according to claim 1, wherein the bonding between the thin plate-shaped piezoelectric substrates or the bonding between the thin plate-shaped piezoelectric substrates and the thin plate-shaped substrate is a frictional force. Manufacturing method Piezoelectric vibrator. 7. The piezoelectric vibration according to claim 1, wherein an organic adhesive is used for joining the thin plate-shaped piezoelectric substrates or for joining the thin plate-shaped piezoelectric substrates to each other. Element manufacturing method Piezoelectric vibrator. 8. The method according to claim 1, wherein the through-hole is formed by a mechanical or etching method.