JP2011124752A - Piezoelectric device and sealing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric device which can be manufactured with sufficient accuracy while simplifying a manufacturing process. <P>SOLUTION: The piezoelectric device includes: a piezoelectric vibration chip 2, a package body 4 comprising a glass substrate and supporting a part of the piezoelectric vibration chip 2 fixedly, and a cover 5 fixed to the package body 4 and having space to accommodate the piezoelectric vibration chip 2. The package body 4 has through-holes 6 and 7. The cross-sectional shape of the through-holes 6 and 7 in the length direction is narrow in the center for the openings on the both sides. Furthermore, a conductive film 13 is formed on the inner peripheral surface of the through-holes 6 and 7. The central part of the through-holes 6 and 7 in the length direction is filled and sealed with the same material as that of the conductive film 13. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a piezoelectric device in which a piezoelectric vibrating piece is enclosed in a package, and a method for sealing the piezoelectric device.

Conventionally, as this type of piezoelectric device, for example, the one described in Patent Document 1 is known.
This conventional piezoelectric device includes a piezoelectric vibrating piece and a package that accommodates the piezoelectric vibrating piece. The package includes a container body made of ceramic or the like in which a piezoelectric vibrating piece is accommodated, and a lid that closes the opening of the container body, and the lid is joined to the container body. A conductive through hole is formed in the container body in order to electrically connect the piezoelectric vibrating piece and a mounting terminal provided outside the container body.

The container body is formed by stacking a plurality of substrates so as to obtain a desired shape. For this reason, for example, in manufacturing the container body, first, an aluminum oxide ceramic sheet is formed as an insulating material. Next, processing such as drilling and circuit printing is performed on each of the plurality of sheets. Further, a plurality of processed sheets are laminated to form cut grooves, and then fired.
Therefore, in the conventional piezoelectric device, the manufacturing process of the container main body is complicated, and a large shrinkage occurs at the stage from the forming of the sheet to the baking, and the dimensional accuracy becomes a problem. For this reason, in addition to simplification of the manufacturing process, there has been a demand for the appearance of a piezoelectric device that can be manufactured with high accuracy.

JP 2006-311090 A

  Accordingly, an object of some aspects of the present invention is to provide a piezoelectric device that can be manufactured with high accuracy and a method for sealing the piezoelectric device, in addition to simplifying the manufacturing process.

In order to solve the above problems and achieve the object of the present invention, the present invention is configured as follows.
One aspect of the piezoelectric device according to the present invention includes a piezoelectric vibrating piece, a package body made of a glass substrate, a part of the piezoelectric vibrating piece being supported and fixed, and a space for accommodating the piezoelectric vibrating piece, A lid fixed to the package body, the package body has a through-hole, and the cross-sectional shape in the length direction of the through-hole is narrower at the center than the openings on both sides, and A conductive film is formed on the inner peripheral surface of the through hole, and a central portion in the length direction of the through hole is closed with the same material as the conductive film.
According to such a configuration, the manufacturing process can be simplified and the manufacturing can be performed with high accuracy.

The through-hole is formed by irradiating a laser beam along a path in the package main body where the through-hole is formed to form an altered portion and etching the altered portion.
According to such a configuration, when forming a through hole, a desired through hole can be formed by laser light and etching.
The formation of the conductive film on the inner peripheral surface of the through hole and the closing of the central portion of the through hole are performed by plating.
According to such a configuration, the through hole conduction process and the blocking process can be realized simultaneously.

Further, one aspect of the method for sealing a piezoelectric device of the present invention is a method for sealing a piezoelectric device in which a piezoelectric vibrating piece is sealed in a package, wherein a part of the package is made of a glass substrate, In order to form a through hole in the glass substrate, a first step of forming an altered portion by irradiating a laser beam along a path inside the glass substrate where the through hole is formed; Etching the portion to form the through hole, plating the through hole, electrically connecting the inner side and the outer side of the glass substrate, and at least a central portion of the through hole A third step of closing.
According to this method, the manufacturing process can be simplified and a highly accurate piezoelectric device can be obtained.

Further, in the first step, a glass substrate thicker than the length of the through hole is prepared as the glass substrate, and the inside of the prepared glass substrate excluding the front and back sides and the path through which the through hole is formed. A laser beam is radiated along to form an altered portion.
According to this, the process for obtaining a desired through-hole can be simplified.
Further, in the first step, in order to further form a cutting groove for cutting in a predetermined region of the glass substrate, a laser is formed along the depth direction of the cutting groove forming region inside the glass substrate. Irradiating light and irradiating the laser beam in the depth direction at a predetermined interval in the length direction of the formation region of the cutting groove to form an altered portion. Etching is performed to form the cut groove.
According to this, when forming a through-hole in a glass substrate, a cutting groove can be formed in a glass substrate collectively.

1 shows a cross-sectional view of an embodiment of a piezoelectric device of the present invention. Sectional drawing which shows a part of modification of embodiment of the piezoelectric device of this invention is shown. It is process drawing of embodiment of the manufacturing method of the piezoelectric device of this invention. It is explanatory drawing explaining the relationship between a laser processing and an etching. It is sectional drawing which shows the filling state by plating of a through-hole.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment of piezoelectric device)
FIG. 1 is a cross-sectional view showing a configuration of an embodiment of a piezoelectric device of the present invention.
As shown in FIG. 1, the piezoelectric device 1 includes a piezoelectric vibrating piece 2 such as a crystal piece and a package 3 in which the piezoelectric vibrating piece 2 is accommodated. The piezoelectric vibrating piece 2 is enclosed in the package 3. It is like that.

As shown in FIG. 1, the package 3 has a package main body 4 in which a part of the piezoelectric vibrating reed 2 is supported and fixed, and a space 5 for accommodating the piezoelectric vibrating reed 2, and a lid 5 fixed to the package main body 4. And.
The package body 4 is made of a glass substrate (glass plate) that transmits light, and silica borosilicate glass, tempered glass, or the like is used. Through holes 6 and 7 are formed at predetermined positions of the package body 4 so as to penetrate from the inside to the outside.

  Each of the through holes 6 and 7 has a cross-sectional shape in the length direction in which the opening portions on both sides are wide and the center portion is narrower than the opening portions on both sides. Specifically, as shown in FIG. 1 or FIG. 4, the diameters of the through holes 6 and 7 are the largest at the openings on both sides, and gradually decrease from the openings on both sides toward the center. It is formed to become. In other words, each of the through holes 6 and 7 has a drum-shaped cross-sectional shape in the length direction.

The through hole 6 is electrically connected to the inner peripheral surface of the through hole 6 in order to electrically connect (conductive) the wiring patterns 8 and 10 formed by copper plating or the like on the inner side surface and the outer side surface of the package body 4. A functional film is formed. Further, the central portion of the through hole 6 is closed by filling the same material as that of the conductive film.
Specifically, a conductive thin film (not shown) such as Cr—Au is formed on the inner peripheral surface of the through hole 6 by sputtering or the like, and the conductive film 13 is formed on the conductive thin film by copper plating or the like. Is formed. Furthermore, at least the central part of the through hole 6 is filled with the same material as the conductive film 13 by copper plating or the like and is blocked. The conductive film 13 is connected to the wiring patterns 8 and 10.

Similarly, the through hole 7 is electrically connected to the inner peripheral surface of the through hole 7 in order to electrically connect the wiring patterns 9 and 11 formed by copper plating or the like on the inner side surface and the outer side surface of the package body 4. A functional film is formed. Further, the central portion of the through hole 7 is closed by filling the same material as that of the conductive film.
Specifically, a conductive thin film (not shown) such as Cr—Au is formed on the inner peripheral surface of the through-hole 7 by sputtering or the like, and the conductive film 15 is formed on the conductive thin film by copper plating or the like. Is formed. Further, at least the central portion of the through hole 7 is filled with the same conductive material as the conductive film 15 by copper plating or the like and is blocked. The conductive film 15 is connected to the wiring patterns 9 and 11.

In the piezoelectric vibrating piece 2, an electrode (not shown) provided on one end side thereof is fixed to the wiring pattern 8 via a conductive silicon resin 16.
The lid 5 is made of metal and formed by press working, and a housing portion that is a space for housing the piezoelectric vibrating piece 2 is formed. Examples of the metal used for the lid 5 include an Fe-based alloy, a copper-based alloy, and an Al-based alloy. Stainless steel is preferable in that it does not require surface plating.

The lid 5 having such a configuration is fixed to the package body 4 so as to cover the piezoelectric vibrating piece 2. The lid 5 is fixed by adhering the lid 5 to the package body 4 with a brazing material 17.
As described above, since the piezoelectric device according to this embodiment uses a glass substrate having a small thermal shrinkage, the manufacturing process can be simplified as compared with the conventional method, and a highly accurate piezoelectric device is obtained. be able to.
In the piezoelectric device according to this embodiment, when plating is performed on the through hole, the conduction process and the blocking process can be realized simultaneously.

(Variations of piezoelectric devices)
Next, a modification of the piezoelectric device of the present invention will be described with reference to FIG.
This modification is based on the configuration of the piezoelectric device 1 shown in FIG. 1 and differs in the method of mounting the piezoelectric vibrating reed 2 on the package body 4.
For this reason, the same elements as those of the piezoelectric device 1 shown in FIG.

The piezoelectric device 1a shown in FIG. 2A is configured so that one end side of the piezoelectric vibrating piece 2 is fixed to the wiring pattern 8 via the metal plate mounting portion 18 instead of the conductive silicon resin 16 shown in FIG. did.
In the piezoelectric device 1b shown in FIG. 2B, a resin base mount 19 is formed on the package body 4 instead of the conductive silicon resin 16 shown in FIG. 1, and a wiring pattern is formed on the resin base mount 19. 8 was formed. Then, one end side of the piezoelectric vibrating piece 2 is fixed to the wiring pattern 8 on the resin base mount 19.

(Embodiment of Piezoelectric Device Manufacturing Method)
Next, an embodiment of a method for manufacturing a piezoelectric device of the present invention will be described with reference to FIGS.
In this example, a manufacturing method for manufacturing a plurality of (for example, several hundred) piezoelectric devices 1 shown in FIG. 1 at a time using a glass substrate will be described.
First, as shown in FIG. 3A, a glass substrate 30 having a predetermined thickness T is prepared. The thickness T of the prepared glass substrate 30 is assumed to be thicker than the lengths of the through holes 6 and 7 (see FIG. 3E) formed in the glass substrate 30.
Here, the size of the glass substrate 30 to be prepared is, for example, 50 mm in length and width, and a thickness T of 0.4 mm.

Next, as shown in FIG. 3 (B), the laser light is emitted along the path in which the through holes 6 and 7 (see FIG. 3 (E)) are to be formed inside the glass substrate 30 except for the front and back sides. Irradiation is performed to form altered portions (altered layers) 31 and 32 (see FIG. 4). The laser light irradiation is performed by condensing the laser light using a lens and scanning (moving) the condensing point along the path.
Further, the cutting groove 33 is formed in a region (position) where the cutting grooves 33 and 34 (see FIG. 3E and the like) for cutting the glass substrate 30 are to be formed inside the glass substrate 30 except for the front and back sides. , 34 is irradiated with laser light along the depth method. Further, the laser beam irradiation in the depth direction is performed at predetermined intervals in the length direction of the cutting grooves 33 and 34. Thereby, the altered portions 35 and 36 are formed in the regions where the cut grooves 33 and 34 are to be formed, respectively (see FIG. 4).

Here, as an example of laser light irradiation conditions, a femtosecond laser having a wavelength of 800 [nm] is used, the spot diameter is 5 [μm], and the energy per pulse is 20 [μJ].
The altered portions 31, 32, 35, and 36 formed on the glass substrate 30 refer to portions where alteration occurs due to, for example, the density, refractive index, mechanical strength, and other physical characteristics of the glass substrate 30 differing from the surroundings. A portion that can be easily removed by etching.

Next, as shown in FIGS. 3C to 3E, the glass substrate 30 is etched under predetermined conditions. As the etchant, for example, boiling acid is used.
In the initial stage of etching, the front and back surfaces of the glass substrate 30 are etched, and the glass substrate 30 becomes gradually thinner. When the etching proceeds to the altered portions 31 and 32, the glass substrate 30 is in the state shown in FIG.
The altered portions 31 and 32 are 3 to 5 times faster in etching than portions other than the altered portions 31 and 32. For this reason, the altered portions 31 and 32 are etched at a high speed, and the glass substrate 30 after the start is in the state of FIG.

Then, when etching proceeds to the altered portions 35 and 36, etching of the altered portions 35 and 36 is started. The altered portions 35 and 36 are 3 to 5 times faster in etching than portions other than the altered portions 31, 32, 35 and 36. For this reason, the altered portions 35 and 36 are etched at a high speed.
Thereafter, etching of the altered portions 31, 32, 35, and 36 proceeds, and when etching is completed at a predetermined timing, the desired through holes 6 and 7 and the cutting grooves 33 are formed in the glass substrate 30 as shown in FIG. , 34 are formed respectively.
Thus, in this manufacturing method, in order to form a through-hole or a cutting groove in the glass substrate, the altered portion is formed by laser light inside the glass substrate, and the etching rate of the altered portion is changed to a portion other than the altered portion. By utilizing the property of high speed, a through hole or a cutting groove having a desired size was formed.

Therefore, the relationship between laser processing and etching will be described in detail with reference to FIG.
As shown in FIG. 4, the depth Y to the formation start position of the altered portion 31 by the laser beam for obtaining a desired plate thickness t and D3 = φ is expressed by the following equation (1).
Y = {A (Tt) -T} / {2 (A-1)} (1)
Here, A = (etching rate of the altered portion 31) / (etching rate other than the altered portion 31). T is the original thickness of the glass substrate 30 before etching (see FIG. 3A), and t is the thickness of the glass substrate 30 after etching (see FIG. 3E).

And the dimension D1 of the opening part of the through-hole 6 is obtained by following (2) Formula, and the minimum diameter D3 of the through-hole 6 is obtained by following (3) Formula.
D1 = T−t−2Y + φ (2)
D3≈φ (3)
If D3 is greater than φ, it can be adjusted by reducing Y. In this case, the diameter of D3 is as follows.
D3 = (T−t−2Y) − (T−2Y) / A + φ
Here, φ is the diameter of laser processing (the diameter of the altered portion 31).

Moreover, the depth Z to the formation start position of the altered portions 35 and 36 by the laser light related to the cutting grooves 33 and 34 is obtained by the following equation (4).
Z = {TA (Tt) -R} / {2 (1-A)} (4)
Here, R is the thickness of the remaining thickness of the glass substrate 30 in the cut grooves 33 and 34.
Furthermore, the dimension D2 of the width method of the opening part of the cutting grooves 33 and 34 can be obtained by the following equation (5).
D2 = T−t−2Z + φ (5)
Note that the above calculation formula may be somewhat different due to variations in the concentration of the etchant, the glass material, laser modification, and the like. Further, it is necessary to adjust the etching time so as to obtain a desired thickness t.

Next, as shown in FIG. 3F, Cr—Au or the like is formed on the inner peripheral surfaces of the through holes 6 and 7 and on the front and back surfaces of the glass substrate 30 where the wiring patterns 8 to 11 are formed. Conductive thin films (not shown) are formed by sputtering. For pattern formation at this time, a lithography technique, a metal mask method, or the like is used.
Thereafter, a plating process such as copper plating is performed on the conductive thin film in order to increase conductivity. As a result, as shown in FIG. 3 (G), the conductive patterns 13 and 15 are formed on the inner peripheral surfaces of the through holes 6 and 7 at the same time as the wiring patterns 8 to 11 are formed on the glass substrate 30. At this time, since the copper plating is simultaneously deposited on the inner peripheral surfaces of the through holes 6 and 7, the minimum part of the hole diameter of the through holes 6 and 7 (the center part of the through hole length method) is finally made of copper. It becomes a closed state by plating (see FIG. 5).

In the plating process, Au flash plating is applied at the final stage to ensure corrosion resistance and solderability.
In the next step, the piezoelectric vibrating piece 2 shown in FIG. 1 is mounted on the glass substrate 30. At this time, the conductive silicon resin 16 is formed on the wiring pattern 8 (see FIG. 1), and one end side of the piezoelectric vibrating piece 2 is fixed to the wiring pattern 8 via the conductive silicon resin 16.
The conductive silicon resin 16 is formed on the wiring pattern 8 by, for example, a syringe-type dispenser or screen printing.

Thereafter, the lid 5 is fixed on the glass substrate 30 so as to cover the piezoelectric vibrating reed 2 mounted on the glass substrate 30, and then the glass substrate is used using the cutting grooves 33 and 34 provided on the glass substrate 30. When 30 is cut, a piezoelectric device 1 as shown in FIG. 1 is obtained.
As described above, according to such a manufacturing method, since a glass substrate having a small thermal shrinkage is used, the manufacturing process can be simplified as compared with the conventional method, and a highly accurate piezoelectric device is obtained. be able to.

Also, according to this manufacturing method, since a glass substrate having a small thermal shrinkage is used, there is no dimensional change during processing as compared with the case of using ceramics, and piezoelectric vibration occurs in the state of the glass substrate (wafer state). A piece can be mounted (embedded).
Furthermore, according to this manufacturing method, when forming a through-hole in a glass substrate, a cutting groove can be formed in a glass substrate together.

  DESCRIPTION OF SYMBOLS 1, 1a, 1b ... Piezoelectric device, 2 ... Piezoelectric vibrating piece, 3 ... Package, 4 ... Package main body, 5 ... Cover body, 6, 7 ... Through-hole, 8- DESCRIPTION OF SYMBOLS 11 ... Wiring pattern, 13, 15 ... Conductive film, 16 ... Conductive silicon resin, 30 ... Glass substrate, 31, 32, 35, 36 ... Alteration part, 33, 34. ..Cutting grooves

Claims (6)

A piezoelectric vibrating piece;
A package body made of a glass substrate and supported by a part of the piezoelectric vibrating piece;
A space for accommodating the piezoelectric vibrating piece, and a lid fixed to the package body,
The package body has a through-hole, and the cross-sectional shape in the length direction of the through-hole is narrow at the center with respect to the openings on both sides,
Furthermore, a conductive film is formed on the inner peripheral surface of the through hole, and a central portion in the length direction of the through hole is closed with the same material as the conductive film.   The through hole is formed by irradiating a laser beam along a path in the package main body where the through hole is formed to form an altered portion and etching the altered portion. The piezoelectric device according to claim 1.   The piezoelectric device according to claim 1 or 2, wherein the formation of the conductive film on the inner peripheral surface of the through hole and the closing of the central portion of the through hole are performed by plating. A piezoelectric device sealing method in which a piezoelectric vibrating piece is enclosed in a package,
A part of the package is made of a glass substrate,
In order to form a through hole in the glass substrate, a first step of forming an altered portion by irradiating a laser beam along a path inside the glass substrate and forming the through hole;
A second step of etching the altered portion to form the through hole;
Plating the through hole, electrically connecting the inside and outside of the glass substrate, and at least closing the central portion of the through hole;
A method for sealing a piezoelectric device, comprising:   In the first step, a glass substrate thicker than the length of the through hole is prepared as the glass substrate, and the inside of the prepared glass substrate excluding the front and back sides is along a path in which the through hole is formed. The method for sealing a piezoelectric device according to claim 4, wherein the altered portion is formed by irradiating a laser beam. In the first step, in order to further form a cutting groove for cutting in a predetermined region of the glass substrate, laser light is emitted along the depth direction of the forming region of the cutting groove inside the glass substrate. Irradiating and performing laser beam irradiation in the depth direction at predetermined intervals in the length direction of the formation region of the cutting groove to form an altered portion,
5. The method for sealing a piezoelectric device according to claim 4, wherein, in the second step, the altered portion is etched to form the cut groove.

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