JP2004248113A - Package structure of piezoelectric device and method for manufacturing piezoelectric device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the dimensional accuracy of a piezoelectric device and to attain its cost reduction while meeting the requirements for downsizing and thinning. <P>SOLUTION: The package 11 of a crystal resonator comprises a base 13 where an insulation layer 16 is formed on the surface by applying Tafram processing to an aluminium plate and an aluminium cover 14 formed in a box shape. Connection electrodes 17a and 17b formed on a vibration piece mounting surface of the base are electrically connected with external electrodes 18a and 18b on a base rear surface through via holes 15a and 15b formed in the base. The cover is joined to the top surface of the base mounted with a crystal vibration piece 12 and the via holes are subsequently sealed airtight by filling material 24. Both a crystal vibration piece of a thickness sliding mode and a tuning fork type one are mountable. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a surface mount type piezoelectric device such as a piezoelectric vibrator or a piezoelectric oscillator used for various electronic devices, and in particular, a package structure for hermetically sealing and mounting a piezoelectric vibrating piece therein, and a package structure thereof. And a method for manufacturing such a piezoelectric device.
[0002]
[Prior art]
Conventionally, piezoelectric devices such as a piezoelectric vibrator, a piezoelectric oscillator, and a real-time clock module, which are widely used as a clock source of an electronic circuit in various electronic devices, are becoming more and more compact as electronic devices become smaller and thinner. In addition to demands for miniaturization and thinning, surface mount types suitable for mounting on circuit boards and the like are often used. In general, a surface mount type piezoelectric device has a piezoelectric vibrating reed mounted on a box-shaped base having a structure in which a sheet material of an insulating material is laminated, as described in Patent Documents 1 and 2 and the like by the present applicant. A package is hermetically sealed by joining a lid to the package.
[0003]
FIG. 7 shows a typical example of a conventional surface mount type piezoelectric vibrator in which an AT-cut crystal vibrating piece 2 is sealed in a package 1. The package 1 has a box-shaped base 3 having a two-layer structure in which a rectangular plate-shaped sheet material 3a and a rectangular frame-shaped sheet material 3b made of a ceramic material are stacked, and a seal ring 4 formed on the upper end thereof by, for example, seam welding. And a metal lid 5 joined thereto. Exciting electrodes 6 are formed on both sides of a rectangular quartz thin plate, and the extraction electrodes from the respective excitation electrodes 6 are aligned with the connection electrodes 7 provided on the surface of the base 3 at the base end of the quartz vibrating reed 2. It is mounted in a cantilever manner with the adhesive 8. The connection electrode 7 is electrically connected to an external electrode 10 formed on the back surface of the base 3 via a lead 9 wired on the surface of the ceramic sheet 3a.
[0004]
Further, as described in Patent Documents 3 and 4, a structure in which a piezoelectric vibrating reed is mounted on a package formed of a conductive material such as a metal plate and hermetically sealed as a surface mount type piezoelectric device is described. Are known. The surface mount type piezoelectric vibrator described in Patent Document 3 has a through hole formed in a bottom surface of a base formed by shaping a metal plate into a dish shape, a hollow insulating material is fitted into the through hole, and a conductive material is filled therein. A piezoelectric piece is fixedly held at the exposed end of the base with a conductive adhesive, electrodes are led out to the outer plate surface of the base, and the base opening is hermetically sealed with a metal lid. Further, the document describes a configuration in which an insulating film is applied to a predetermined position on the outer surface and the inner side of the base, a conductive film is formed at the predetermined position, and the inner and outer conductive films are electrically connected. . Patent Literature 4 describes a quartz resonator in which a quartz vibrating piece is hermetically sealed with a base and a lid made of a conductive material, similarly to Patent Literature 3, and the base is inserted through the quartz resonator. A hole is provided, and a terminal is inserted into the insertion hole while being electrically insulated from the base by an insulating portion, and a crystal vibrating piece is connected to the terminal to be cantilevered.
[0005]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2002-9576 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-135074 [Patent Document 3] Japanese Patent Application Laid-Open No. 3-113907 [Patent Document 4] Japanese Patent Application Laid-Open No. 2002-280868 [0006] ]
[Problems to be solved by the invention]
In the conventional piezoelectric device package described above with reference to FIG. 7, each ceramic sheet material forming the base is usually formed by firing a green sheet. However, the green sheet has the property of shrinking in the vertical and horizontal directions during firing, and the shrinkage rate is not always constant, so that the dimensional accuracy of the base on which the sheet material is finally laminated may be reduced. Furthermore, as the piezoelectric device becomes smaller and thinner, it is more difficult to secure the dimensional accuracy of the base, that is, the package, and to further improve the size.
[0007]
Further, in the conventional metal package described in Patent Documents 3 and 4, a hole provided in the base and a terminal passing through the hole are electrically insulated by an insulating member such as glass and hermetically sealed. I do. For this reason, the airtightness between the base and the insulating member or between the insulating member and the terminal may be impaired, particularly by long-term use, and the reliability and life of the piezoelectric device may be reduced, and the performance may be deteriorated or completely impaired. Further, as the size and thickness of the piezoelectric device are reduced, it becomes more difficult to ensure sufficient airtightness between the base and the insulating member and between the insulating member and the terminal during the manufacture.
[0008]
Therefore, an object of the present invention is to provide a surface mount type piezoelectric device in which a piezoelectric vibrating reed is mounted in a package, and to further improve the dimensional accuracy while meeting the demand for miniaturization and thinning. Another object of the present invention is to provide a package structure capable of securing and maintaining higher dimensional accuracy.
Another object of the present invention is to provide a method of manufacturing a piezoelectric device having a package structure capable of ensuring high dimensional accuracy and reliability while reducing the size and thickness as described above.
[0009]
[Means for Solving the Problems]
According to the present invention, in order to achieve the above object, a base for mounting a piezoelectric vibrating reed, and a lid joined to an upper portion of the base to hermetically seal the piezoelectric vibrating reed therein, Is formed of a metal material and has an insulating layer whose surface is insulated.On the mounting surface of the piezoelectric vibrating reed, a connection electrode for connecting the piezoelectric vibrating reed on the insulating layer is provided on the back surface. External electrodes are respectively formed on the insulating layer, the connection electrodes and the corresponding external electrodes are electrically connected through via holes formed in the base, and the via holes are hermetically sealed with a filling material. A package structure for a closed piezoelectric device is provided.
[0010]
Thus, even if the base made of a metal material is reduced in size and thickness, it can be processed into a desired outer shape with high dimensional accuracy, so that the dimensional accuracy of the package can be improved. In addition, since the insulating layer formed by the surface insulating treatment is integrated with the base material of the base, it is difficult to peel off, which is convenient. In addition, since the via holes can be arranged at any appropriate positions on the base surface, the degree of freedom in designing the connection electrodes, the external electrodes, and the wiring patterns connected to them is improved. Further, since the via hole can be used to seal the inside of the package after the lid is joined, the via hole can be applied to any of the piezoelectric vibrating reed and the tuning fork vibrating reed in the thickness-shear mode.
[0011]
As the metal material forming the base, aluminum is preferable in view of its workability, price, and the like. In this case, the insulating layer is formed of, for example, an alumite film formed by an anodizing treatment, and its corrosion resistance and surface hardness. It is preferable from the viewpoint of adhesion to the base material and the like. Furthermore, in the case where the metal material is aluminum, the insulating layer has a corrosion resistance that is further increased than that of alumite because the tuffram film formed by the tuffram (registered trademark) treatment of impregnating with Teflon (registered trademark) after the alumite conversion is performed. preferable. When the insulating layer has a thickness of at least about 5 μm, sufficient insulating properties can be ensured.
[0012]
In one embodiment, the base is formed of a flat plate and the lid is formed in a box shape, and a space for mounting the piezoelectric vibrating reed therein is defined by joining them. A flat base can be more easily manufactured.
[0013]
In another embodiment, the base is box-shaped and the lid is formed of a flat plate, and a space for mounting the piezoelectric vibrating reed is defined inside the base. The flat base is easier to manufacture than the box-shaped lid, can reduce the cost, and can reduce the welding margin for joining to the base, so that the package can be further downsized. The box-like shape of the base can be formed of a structure in which a plurality of metal plates are stacked, similarly to the base made of the conventional ceramic material described above with reference to FIG. Further, since the base has a box-like shape, the workability of the metal plate is good, so that an integrated structure having a recess formed on one surface thereof can be used.
[0014]
Further, according to the present invention, a metal plate is processed into an outer shape of a base of a piezoelectric device, two through holes are formed in the metal plate, and a surface of the metal plate including these through holes is insulated to form a through hole. A conductive material is formed on the inner surface of the metal plate to form a via hole.Connecting electrodes for connecting the piezoelectric vibrating reed to the piezoelectric vibrating reed mounting surface of the metal plate, and external electrodes on the back surface of the metal plate are formed in a predetermined pattern. And, by forming the corresponding connection electrode and the external electrode so as to be electrically connected via the via hole, the process of forming the base, mounting the piezoelectric vibrating reed on the base, and closing the lid There is provided a manufacturing method including a step of joining and hermetically sealing, and a step of hermetically closing a via hole.
[0015]
The processing of this metal plate can be performed by, for example, etching or machining, and the base has high dimensional accuracy. Therefore, the piezoelectric device has high dimensional accuracy and low cost while responding to the demand for miniaturization and thinning. Can be manufactured. In addition, the arrangement of via holes is relatively free, and accordingly, connection electrodes, external electrodes, and wiring patterns can be designed and formed more freely. Furthermore, since the via hole is closed after the lid is joined to the base, the inside of the package can be hermetically sealed with an appropriate gas or vacuum atmosphere, and the piezoelectric device has a thickness-shear mode piezoelectric vibrating piece or tuning fork type. Any of the resonator elements can be mounted.
[0016]
In one embodiment, the metal plate is made of aluminum, which can be easily insulated by alumite treatment, and has a base excellent in corrosion resistance and surface hardness, adhesion to a base material, and the like. Can be formed. Further, in another embodiment, similarly, the metal plate is made of aluminum, which can be easily insulated by a tuffram treatment of impregnating with Teflon after the alumite treatment to form a base having higher corrosion resistance. Can be.
[0017]
In the manufacturing method of the present invention, the package of the piezoelectric device may have a base in a flat plate shape and a lid in a box shape, or a base in a box shape and a lid in a flat plate shape. In the case where the base is formed in a box shape, in one embodiment, the box shape can be formed by laminating a frame-shaped metal plate on the piezoelectric vibrating piece mounting surface of the metal plate. In another embodiment, in order to form the box shape, a recess is formed in the surface of the metal plate on which the connection electrode is to be formed, and then the metal plate is insulated.
[0018]
Further, in one embodiment, a plurality of bases can be formed on the metal plate at the same time, thereby enabling miniaturization and thinning while ensuring high dimensional accuracy, and stabilizing a high quality piezoelectric device. And can be mass-produced.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
1A and 1B schematically show a preferred embodiment of a crystal resonator to which the present invention is applied. An AT-cut crystal resonator element 12 is hermetically sealed in a package 11. The package 11 includes a base 13 of a substantially rectangular flat plate made of aluminum and a lid 14 joined to the upper surface thereof. The lid 14 is formed in a box shape in which a cavity for accommodating the quartz-crystal vibrating piece 12 is defined by, for example, drawing aluminum.
[0020]
The base 13 is provided with two via holes 15a and 15b having a conductive film formed on the inner surface near one end in the longitudinal direction. The surface of the base 13 is pre-insulated, including the via holes. In the present embodiment, the anodized aluminum oxide is anodized, and then a Teflon (registered trademark) process of impregnating with Teflon (registered trademark) is performed, whereby the insulating layer 16 made of a tuffram coating is formed to a predetermined thickness. . This thickness is at least about 5 μm, preferably about 15 μm, to achieve the desired electrical insulation effect. Also, the base 13 can be subjected to a desired insulating treatment only by alumite.
[0021]
A pair of connection electrodes 17a, 17b is formed on the surface of the base 13 on which the quartz vibrating reed is mounted in a pattern that is electrically connected to the corresponding via hole on the one longitudinal end side. As shown in FIG. 2A, a pair of external electrodes 18a and 18b are formed on the rear surface of the base 13 near both ends in the longitudinal direction, and are electrically connected to the via holes and the leads 19a and 19b. It is connected to the. Thereby, the corresponding connection electrodes 17a and 17b and the external electrodes 18a and 18b are electrically connected to each other. These electrodes and leads are generally formed by patterning a metal wiring material such as W or Mo on the surface of the base 13 by screen printing, and then plating Ni and Au thereon.
[0022]
FIG. 2B shows a pattern of external electrodes 18a and 18b different from that of FIG. 2A. Both external electrodes extend near the longitudinal ends of the base 13 near the via holes 15a and 15b. Is provided. In this manner, the external electrodes 18a and 18b can be designed and wired in various patterns on the back surface of the base 13 as required. Also, the via holes 15a and 15b can be arranged at positions different from those in the above-described embodiment in correspondence with the external electrodes 18a and 18b and the wiring patterns. Wiring can be performed so as to be connected to the electrodes 17a and 17b.
[0023]
FIG. 2 (C) shows a modification of FIG. 2 (A), and substantially the entire back surface of the base 13 is made of a suitable insulating material except for the vicinity of the longitudinal end where the external electrodes 18a and 18b are arranged. The resin is coated with the insulating film 20 by spray coating. As a result, most of the via holes 15a and 15b and the leads 19a and 19b are insulated, so that current leakage and short circuit can be prevented, and more stable operation of the crystal unit can be ensured.
[0024]
The quartz-crystal vibrating piece 12 is formed of a rectangular quartz thin plate. Excitation electrodes 21 are formed on both surfaces of the quartz-crystal vibrating piece 12, and extraction electrodes 22 and 22 from the respective excitation electrodes are formed on one end, that is, a base end. Have been. The quartz-crystal vibrating piece 12 is fixed at a base end thereof with the respective connecting electrodes 17a and 17b of the base 13 in a cantilever manner with a conductive adhesive 23 and electrically connected thereto.
[0025]
After adjusting the frequency of the crystal resonator element 12 mounted on the base 13 in this way, the lid 14 is bonded to the base 13 in a nitrogen or vacuum atmosphere and sealed. Next, each via hole 15a, 15b is airtightly closed with a suitable filler 24. Thus, the inside of the package 11 is hermetically sealed in a nitrogen or vacuum atmosphere. As the filler 24, for example, a low melting point metal such as Au. Sn or Au. Ge is suitable. Balls of such a metal are arranged in the openings of the via holes 15a and 15b from the outside of the package, and this is The via holes 15a and 15b can be filled by melting with a beam or the like.
[0026]
The lid 14 made of aluminum can be joined to the base 13 by, for example, welding using an electron beam. When the lid 14 is made of the same metal as the base 13, the thermal expansion coefficient becomes the same, which is advantageous when welding them. In addition, the lid 14 can be joined by another known means using a metal brazing material such as solder or low melting point glass. Furthermore, if the surface of the lid 14 is insulated similarly to the base 13, the possibility of an electrical short which increases with the miniaturization of the package 11 can be suppressed.
[0027]
3A to 3C show modified examples of the via hole and an electrode or a wiring connected to the via hole. In the via holes 15a (15b) in FIG. 3A, the opening portions 25 of the base 13 on the side where the crystal vibrating piece is mounted and on the back side are chamfered. The conductive film 26 of the via hole 15a (15b) is usually formed by plating a conductive material on the inner surface of the through hole formed in the base 13, but it is more preferably formed by making the opening larger by chamfering. A film can be formed, and good and reliable connection can be made to the connection electrode 17a (17b) and the lead 19a (19b) near the opening. Further, the filling material 24 can be more easily and more reliably hermetically filled.
[0028]
In FIG. 3B, the conductive film 26 is formed by sputtering a conductive material. The connection electrode 17a (17b) and the lead 19a (19b) are formed by the above-described method so as to overlap the portion of the conductive film 26 formed near the opening of the via hole 15a (15b). As described above, by forming each of the electrodes and the wiring pattern separately from the conductive film 26 of the via hole by a different method, the degree of freedom of the pattern and the design is improved.
[0029]
In the embodiment of FIG. 3C, the conductive film 26 of the via hole 15a (15b), the connection electrode 17a (17b) and the lead 19a (19b) connected to the conductive film 26 are formed by sputtering the conductive material. Is formed and a plating layer 27b is laminated thereon. As described above, the conductivity is improved by increasing the thickness of each of the electrodes, the leads, and the conductive film, and more reliable operation of the crystal resonator can be secured.
[0030]
According to the present invention, a large number of the crystal units shown in FIG. 1 can be manufactured simultaneously according to the following steps. First, as shown in FIG. 4, a large number of small aluminum plate pieces 29 serving as a base material of the base 13 are formed on an aluminum plate 28 of a predetermined size by connecting portions 28a at the center of both sides in the longitudinal direction. The base 13 is processed into the outer shape in a state where it is connected to the base 28b, and a through hole 30 for forming the via hole is formed in each base. The outer shape of the base 13 and the processing of the through holes 30 can be performed by wet etching or machining the aluminum plate 28. As described above, the aluminum plate is easy to process and inexpensive, so that the base 13 having higher dimensional accuracy can be obtained as compared with the package made of the conventional ceramic material described above with reference to FIG. It is possible to cope with the demand and to reduce the manufacturing cost.
[0031]
Next, the insulating layer 16 is formed on the surface of each small plate piece 29 including the inner surface of the through hole 30 by the taffram treatment. Further, after forming the via hole by forming a conductive film on the inner surface of the through hole 30 and patterning the connection electrode, the external electrode, and the lead on both surfaces of the small plate piece 29, respectively, cutting the connection portion 28a. Thus, the base 13 shown in FIG. 1 is obtained. After mounting the crystal resonator element 12 on each base 13 and adjusting the frequency, the lid 14 is joined by the above-described method and sealed inside the package 11. Finally, the via holes 15a and 15b are hermetically closed with a filler such as the above-mentioned low melting point metal in a nitrogen atmosphere, thereby completing the crystal unit shown in FIG.
[0032]
In this embodiment, both through-holes 30 are formed in the same size. However, in another embodiment, only one of the through-holes 30 can have a small diameter. In this case, when forming the connection electrode or the external electrode, the smaller through-hole is filled with a conductive material and airtightly closed. The other normal size through hole is used to seal the inside of the package hermetically by closing the lid with the base and then closing the interior with the filler as described above.
[0033]
FIGS. 5A and 5B show another embodiment of the crystal resonator according to the present invention. In this embodiment, the package 31 includes a substantially rectangular box-shaped base 32 on which an aluminum plate is laminated, and a metal lid 33 joined to an upper end thereof. The base 32 is formed by laminating a rectangular frame-shaped frame plate 32b also made of aluminum on a bottom plate 32a made of an aluminum thin plate configured similarly to the base 13 of FIG. Is formed in a box-shaped structure that defines an empty space for accommodating therein. This laminated structure can be easily manufactured by welding an aluminum plate with, for example, an electron beam. It is more convenient if the surface of the frame plate 32b is similarly insulated.
[0034]
The lid 33 is joined to the base 32 by welding using, for example, an electron beam. However, if the lid 33 is formed of aluminum similarly to the embodiment of FIG. 1, the coefficient of thermal expansion becomes the same as that of the base 32, which is advantageous during welding. Further, the lid 33 can be joined by another known means using a metal brazing material such as solder or low-melting glass, and furthermore, if the surface is insulated similarly to the bottom plate 32a, an electric short circuit occurs. This is advantageous because the possibility of the above can be suppressed.
[0035]
In the present embodiment, by joining the flat cover 33 to the box-shaped base 32, the welding margin required for this can be made smaller than in the embodiment of FIG. 1, so that the dimensions of the package 31 can be made smaller. In addition, in the embodiment of FIG. 1, since the drawing process for forming the lid 14 into a box shape is not required, the manufacturing cost can be reduced accordingly.
[0036]
FIG. 6 shows a modification of the crystal unit shown in FIG. In this modification, the base 34 of the package 31 is formed by forming an aluminum plate into a box-shaped structure in which a cavity for accommodating the quartz-crystal vibrating piece 12 is defined. Different from the example. Such a space is formed by half-etching or machining the surface of the aluminum plate on which the connection electrode is to be formed, for example, by wet etching or dry etching to a predetermined depth. In particular, in the case of wet etching, when the outer shape of the base is processed on the aluminum plate by wet etching, it can be advantageously processed according to the flow of the process. The surface of the box-shaped aluminum plate is insulated similarly to the embodiment of FIG. 1 to form an insulating layer 16. The through holes for forming the via holes 15a and 15b may be formed before or after the aluminum plate is formed into a box shape.
[0037]
As described above, the preferred embodiments of the present invention have been described in detail. However, the present invention is not limited to the above embodiments, and various modifications and variations may be made to the above embodiments within the technical scope thereof. can do. For example, the present invention can be similarly applied to a vibrating piece made of various piezoelectric materials other than quartz, such as lithium tantalate and lithium niobate, and a piezoelectric device having a tuning fork-type vibrating piece. Further, the base of the package can be formed of an appropriate metal material such as magnesium in addition to aluminum.
[0038]
As is clear from the above description, according to the package structure of the piezoelectric device of the present invention, the base can be processed into a desired outer shape with high dimensional accuracy, so that the dimensional accuracy of the package can be increased regardless of its size and thickness. In addition to significantly reducing manufacturing costs, the wiring structure using via holes improves the degree of freedom in designing electrodes and wiring patterns, and can be hermetically sealed. A low-cost piezoelectric device that can be mounted with any of the tuning-fork-type vibrating pieces and that can exhibit high reliability and stability can be obtained.
Further, according to the method for manufacturing a piezoelectric device of the present invention, a base can be formed with high dimensional accuracy and low cost by processing a metal plate, and with high dimensional accuracy while responding to the demand for miniaturization and thinning. And it can be manufactured at low cost.
[Brief description of the drawings]
FIG. 1A is a plan view showing a preferred embodiment of a crystal resonator according to the present invention without a package cover, and FIG. 1B is a cross-sectional view taken along the line II.
FIGS. 2A, 2B, and 2C are bottom views showing different embodiments of external electrodes. FIG.
FIGS. 3A, 3B, and 3C are partially enlarged sectional views showing different embodiments of via holes and electrodes or wirings connected to the via holes, respectively.
FIG. 4 is a plan view showing an outer shape of a base and a part of an aluminum plate in which a through hole is formed.
FIG. 5A is a plan view showing another embodiment of the crystal unit according to the present invention with a package lid omitted, and FIG. 5B is a cross-sectional view taken along the line IV-IV.
FIG. 6 is a sectional view similar to FIG. 5B showing a modification of the crystal unit according to the present invention.
FIG. 7 is a cross-sectional view showing an embodiment of a conventional crystal unit.
[Explanation of symbols]
1, 11, 31 Package; 2, 12 Quartz vibrating reed; 3, 13, 32, 34 Base; 5, 14, 33 Lid; 7, 17a, 17b Connection electrode; 8, 23 Conductive adhesive; 9, 19a, 19b lead; 10, 18a, 18b external electrode; 15a, 15b via hole; 16 insulating layer; 24 filler; 32a bottom plate;

Claims (14)

A base for mounting the piezoelectric vibrating reed, and a lid joined to an upper portion of the base and hermetically sealing the piezoelectric vibrating reed therein,
The base is formed of a metal material, and has an insulating layer whose surface is insulated,
On the piezoelectric vibrating reed mounting surface of the base, connection electrodes for connecting the piezoelectric vibrating reed on the insulating layer are formed, and on the back surface, external electrodes are formed on the insulating layer, respectively.
The connection electrode and the corresponding external electrode are electrically connected via a via hole formed in the base, and
A package structure for a piezoelectric device, wherein the via hole is hermetically closed with a filling material. The package structure for a piezoelectric device according to claim 1, wherein the metal material is aluminum, and the insulating layer is made of an alumite film. The package structure for a piezoelectric device according to claim 1, wherein the metal material is made of aluminum, and the insulating layer is made of a TUFRAM (registered trademark) film. 4. The package structure of a piezoelectric device according to claim 1, wherein the insulating layer has a thickness of at least about 5 [mu] m. The package structure for a piezoelectric device according to any one of claims 1 to 4, wherein the base is formed of a flat plate, and the lid has a box shape. The package structure for a piezoelectric device according to any one of claims 1 to 4, wherein the base has a box shape, and the lid is a flat plate. 7. The package structure for a piezoelectric device according to claim 6, wherein the box-like shape of the base has a laminated structure of a metal plate. 7. The package structure of a piezoelectric device according to claim 6, wherein the box-like shape of the base is formed of a metal plate having a recess formed on one surface thereof. A metal plate is processed into an outer shape of a base of a piezoelectric device, two through holes are formed in the metal plate, a surface of the metal plate including the through holes is insulated, and a conductive material is applied to an inner surface of the through hole. A via hole is formed by forming a film, a connection electrode for connecting the piezoelectric vibrating reed to the piezoelectric vibrating reed mounting surface of the metal plate, and an external electrode on the back surface of the metal plate are respectively in a predetermined pattern, and correspond. Forming the base by forming the connection electrode and the external electrode so as to be electrically connected via the via hole;
A process in which a piezoelectric vibrating piece is mounted on the base, and a lid is joined thereto and hermetically sealed,
And c. Sealing the via hole in an airtight manner. The method according to claim 9, wherein the metal plate is made of aluminum, and the insulating process is an alumite process. The method according to claim 9, wherein the metal plate is made of aluminum, and the insulating process is a tuffram process. The base is formed in a box shape by laminating a frame-shaped metal plate on a surface of the metal plate on which the piezoelectric vibrating reed is mounted, and a flat lid is joined to the base. The method for manufacturing a piezoelectric device according to any one of the above. In order to form the base in a box shape, after forming a recess in the surface of the metal plate on which the connection electrode is to be formed, the metal plate is insulated, and a flat lid is joined to the base. The method for manufacturing a piezoelectric device according to claim 9, wherein: 14. The method according to claim 9, wherein a plurality of the bases are formed on the metal plate at the same time.

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