JP2004343571A - Piezoelectric vibration device - Google Patents

Abstract

[PROBLEMS] To provide a piezoelectric vibration device capable of improving impact resistance, responding to miniaturization, and being efficiently manufactured.
An electronic component package (1) has a ceramic package configuration in which necessary electrodes are formed on a package body made of ceramics such as alumina, and has a rectangular parallelepiped shape as a whole, and a recessed electronic component element housing when viewed in cross section. It has a portion 1a. On the side of the electronic component package 1 where the internal connection electrodes are not formed (the other end in the long side direction), an auxiliary support portion 4 made of a silicone resin formed in a film shape and having an elliptical shape in a plan view is formed.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a piezoelectric vibrating device such as a crystal oscillator and a crystal oscillator used for electronic equipment and the like.
[0002]
[Prior art]
A piezoelectric vibrating device often employs a crystal vibrator configuration in which a crystal vibrating element having excitation electrodes formed therein is housed in a semi-package provided with internal wiring, and the vibrating element is hermetically housed. The recent miniaturization of quartz resonators is rapidly progressing, and the miniaturization of quartz resonator elements housed in packages is also progressing. Such an ultra-small quartz-crystal vibrating element, for example, an AT-cut quartz plate and a rectangular shape in a plan view is generally used. And the other end was often a free end. Also, when a tuning-fork type quartz vibrating element composed of a pair of vibrating arms and a base connecting the pair is used for the piezoelectric vibrating element, a structure in which the base is used as a support region and the vibrating arm side is a free end is generally used. Used.
[0003]
In such a cantilever support configuration, when the package is joined to the electrode connection portion that has also been received by the conductive joining material, the free end side of the crystal vibrating element is inclined obliquely so as to contact the inner bottom surface of the package body, and In some cases, the cantilever could not be supported parallel to the bottom surface. In order to solve such a problem, Japanese Patent Application Laid-Open No. 3-88373 (Patent Document 1) proposes a configuration in which a pillow member is provided below the other end portion on the free end side of the piezoelectric piece. In Japanese Patent Application Laid-Open No. 3-88373, an insulating bottom plate, at least a pair of holding electrodes provided on one side plate surface of the bottom plate, and an excitation electrode formed on the plate surface are led out to one end, and this lead-out end is described above. The pillow has a piezoelectric piece fixed to the holding electrode with a conductive adhesive and electrically connected to the holding piece, and a pillow member provided on one side of the bottom plate corresponding to the other end of the piezoelectric piece. The effect that the displacement on the free end side can be suppressed by the material was obtained.
[0004]
However, Japanese Unexamined Patent Publication No. 3-88373 discloses that the pillow material is formed by, for example, a metallizing process or the like, but such a structure is rigid and does not have a cushioning function due to elasticity. Therefore, when a large shock is applied to the piezoelectric vibrator from the outside, the shock cannot be completely absorbed by the pillow material, and the quartz vibrating element may be damaged.
[0005]
In recent years, ultra-thinness has also been promoted in response to ultra-small size, and pillow materials are also required to be thinner. Particularly, a pillow material thinner than the thickness of the electrode connection part is required to form a free end in supporting the quartz crystal vibrating element, but elaborate manufacturing was required to manufacture such a configuration by lamination technology. .
[0006]
[Patent Document 1]
JP-A-3-88373
[Problems to be solved by the invention]
The present invention has been made to solve the above problems, and has as its object to provide a piezoelectric vibrating device that can improve impact resistance, can be miniaturized, and can be manufactured efficiently.
[0008]
[Means for Solving the Problems]
The present invention is characterized in that a silicone resin is used as a conductive bonding material for holding one end of a piezoelectric vibrating element and a base material constituting an auxiliary connecting portion located below the other end of the piezoelectric vibrating element. It can be realized by the configuration.
[0009]
The piezoelectric vibrating device according to claim 1, wherein the package main body is made of an insulating material and has a rectangular shape in a plan view, a plurality of electrode connecting portions formed in parallel on one end side in the long side direction of the package main body, and a conductive material provided on the electrode connecting portions. A piezoelectric vibrating element formed with an excitation electrode whose one end is cantilevered by a bonding material; and a buffer function formed below the other end of the piezoelectric vibrating element and at the other end in the long side direction of the package body. And a base material of the conductive bonding material and the auxiliary support portion is made of a silicone resin.
[0010]
The conductive bonding material is made of silicone resin as a base material. A bonding material is added to the bonding material so that the bonding material can be easily supplied to the bonding site and has excellent viscosity and thixotropy for easy handling after the supply. Alternatively, it can be obtained by adding a conductive filler such as metal particles. The auxiliary support is coated with only a silicone resin base material. This silicone resin can be adjusted to liquid, grease-like, rubber-like, or resin-like depending on the degree of polymerization, type of side group, degree of cross-linking, etc., and its properties can be adjusted by additives. By such adjustment, the height and shape of the auxiliary support portion can be adjusted.
[0011]
According to the above configuration, since a silicone resin having a cushioning function is used for the auxiliary support portion, a shock is applied to the piezoelectric vibrating device, and even when the free end of the internal piezoelectric vibrating element strongly hits the package body, the silicone resin is used. By the buffer function described above, the piezoelectric vibrating device is not damaged or a part of the electrode material formed on the piezoelectric vibrating device does not peel off. As a result, the problem that the characteristics such as the frequency fluctuate due to the breakage or peeling is eliminated.
[0012]
Further, by using the same silicone resin as the base material of the conductive bonding material and the auxiliary support portion, it is possible to treat the basic characteristics of the resin, for example, the curing conditions or the exhaust conditions of the contained unnecessary gas, almost equally. Therefore, it is possible to obtain a low-cost piezoelectric vibration device with stable characteristics without requiring an extra manufacturing process.
[0013]
According to a second aspect of the present invention, based on the configuration of the first aspect, the piezoelectric vibrating element is a tuning-fork type piezoelectric vibrating element including a pair of vibrating arms and a base connecting the pair of vibrating arms, and a tip portion of a free end of each of the vibrating arms. A metal film region for frequency adjustment is formed at the base portion, and the auxiliary support portion is formed at least below the metal film region in a cantilever support structure in which the base portion is joined to the electrode connection portion. are doing.
[0014]
The tuning-fork type vibrator has a metal film region for frequency adjustment at the tip of the free end of the vibrating arm. Conventionally, when the free end contacts the package due to an external impact, the metal film may be peeled off. In particular, the metal film for frequency adjustment has a relatively large added mass so that the adjustment range can be widened, and if it comes off, it may lead to a large variation in characteristics. According to the second aspect of the present invention, the silicone resin is used for the auxiliary support having the buffer function, so that even if the piezoelectric vibrating device receives an impact and the free end of the internal piezoelectric vibrating element hits the package body strongly, By the buffer function described above, the piezoelectric vibrating device is not damaged or a part of the electrode material formed on the piezoelectric vibrating device does not peel off. As a result, the problem that the characteristics such as the frequency fluctuate due to the breakage or peeling is eliminated.
[0015]
According to a third aspect of the present invention, the cushioning portion is provided also on the lid side. In the piezoelectric vibration device according to the first or second aspect, the lid portion located above the other end of the piezoelectric vibration element is made of silicone resin. This is a configuration in which a buffer section is formed.
[0016]
According to the third aspect, the buffer portion made of the same base resin as the conductive bonding material is formed on the lid side of the silicone resin. Therefore, even if the package body or the lid is strongly hit, the cushioning function of the silicone resin enables The piezoelectric vibrating device is not damaged, and a part of the electrode material formed on the piezoelectric vibrating device does not peel off. As a result, the problem that the characteristics such as the frequency fluctuate due to the breakage or peeling is eliminated. Further, by using the same silicone resin as the base material of the conductive bonding material and the auxiliary support portion, it is possible to treat the basic characteristics of the resin, for example, the curing conditions or the exhaust conditions of the contained unnecessary gas, almost equally. Therefore, it is possible to obtain a low-cost piezoelectric vibration device with stable characteristics without requiring an extra manufacturing process.
[0017]
Further, as described in claim 4, in the piezoelectric vibration device according to claim 1, 2, or 3, the auxiliary supporting portion may have a film-like configuration made of only silicone resin. As a result of the inventor's intense impact resistance test using a tuning-fork type quartz vibrating element as the piezoelectric vibrating element, it was found that a buffer function was obtained when the thickness of the silicone resin was 20 μm or more. The tuning-fork type quartz vibrating element used in the verification experiment had a long side dimension of 3.2 mm, a short side dimension of 0.5 mm, and a thickness of 0.1 mm, and the width of the vibrating arm was 0.2 mm, respectively. As shown in FIG. 5, the tuning fork type quartz vibrating element has a configuration supporting the base. In the supported state, the distance between the tuning-fork type quartz vibrating element and the bottom surface of the electronic component housing is set to 130 μm. With respect to such a piezoelectric vibration device, the impact resistance was confirmed by changing the thickness of the silicone resin of the auxiliary support portion. When the thickness was 10 μm, a change in frequency was observed after the test, but when the thickness was 20 μm or more, a change in frequency that would be a problem in practice was not observed. However, in consideration of contact with the free end of the piezoelectric vibrating element and reduction in the height of the piezoelectric vibrating device, it is not preferable to make the piezoelectric vibrating element too thick, and it is preferable to set the thickness to 100 μm or less. Note that the film configuration does not necessarily have to be flat on the upper surface, and there is no problem even if it has a gentle conical shape.
[0018]
Such a film-like silicone resin can be formed relatively easily by applying a liquid-form silicone resin to the package body or the package body and the lid and drying and curing the same.
[0019]
By adopting the silicone resin having the film-like configuration as described above, it is possible to obtain a piezoelectric vibrating device that can be reduced in height and has excellent impact resistance.
[0020]
According to a fifth aspect of the present invention, in the piezoelectric vibration device according to any one of the first to fourth aspects, the height of the auxiliary support portion formed on the package body is １ ／ of the height of the electrode connection portion. The height may be up to 2/3.
[0021]
It is desirable that the height of the auxiliary support portion is as equal as possible to the height of the contact electrode connection portion so as not to make contact with the free end of the piezoelectric vibration device in a steady state. However, since the auxiliary support portion is formed of a silicone resin, the thickness of the auxiliary support portion varies. On the other hand, if the auxiliary support is too thin, the free end may be too low when mounting the piezoelectric vibrating element on the electrode connection, which may result in improper adhesion. When it comes into contact with the lid or the lid, the cushioning function may not be obtained. When the height is outside the above range, that is, when the height of the auxiliary support portion is 1/4 or less of the height of the electrode connection portion, proper bonding may not be performed or a sufficient buffer function may not be obtained. In the case where the thickness is more than 2/3, the piezoelectric vibrating element may not oscillate due to the thickness variation of the silicone resin. Can be secured.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
A first embodiment according to the present invention will be described with reference to FIGS. FIG. 1 is a plan view of an electronic component package according to the present embodiment, and FIG. 2 is a cross-sectional view taken along a line AA of FIG. 1, showing an internal structure sealed with a lid. 3 is a bottom view of the electronic component package of FIG. 1, FIG. 4 is a plan view of a case where the piezoelectric vibration element is mounted on the electronic component package, and FIG. 5 is a BB cross-sectional view of FIG. , The internal structure in a state sealed with a lid.
[0023]
The electronic component package 1 has a ceramic package configuration in which necessary electrodes are formed on a package body made of ceramics such as alumina, and has a rectangular parallelepiped overall shape and a concave electronic component element storage section 1a when viewed in cross section. are doing. A bank portion 10 is formed around the electronic component storage section 1a, and a circumferential metal layer 11 is formed on the upper surface of the bank portion 10. Castellations C1, C2, C3, and C4 are formed vertically at the outer four corners of the electronic component package 1. On the electronic component mounting surface inside the electronic component package 1, internal connection electrodes 12, 13 serving as electrode connection portions are formed on one end side in the long side direction and are arranged side by side in the short side direction. Inside the package, a space one step down is formed. The internal connection electrode 12 is led out of the package at one end in the long side direction, and is electrically connected to the external connection electrode 121 via a lead electrode (not shown). A dummy electrode 12a is connected to the internal connection electrode 12, and extends to the vicinity of the other end in the long side direction below the electronic component mounting surface inside the electronic component package.
[0024]
The internal electrode 13 is led out of the package at the other end in the long side direction, and is connected to the external connection electrode 131 via the extraction electrode 13a. The above-mentioned dummy electrode 12a is set to substantially match the size of the extraction electrode 13a, whereby the capacitance from the internal connection electrode 12 to the external connection electrode 121 and the external connection electrode 13 The capacitances up to the electrode 131 are almost equal. The dummy electrode 12a and the extraction electrode 13a are formed inside the electronic component package 1 below the electronic component storage section 1a by a lamination technique of ceramics and a metallized layer. As shown in FIG. 3, external connection electrodes 121 and 131 are arranged at both ends in the long side direction on the bottom surface of the package, and a part of the external connection electrodes 121 and 131 is extended to the castellation portion, and external connection in the package square region is performed. Is easy.
[0025]
An auxiliary support 4 is formed on the side of the electronic component package 1 where the internal connection electrode is not formed (the other end in the long side direction). The auxiliary support portion 4 is made of a silicone resin formed in a film shape with a thickness of about 50 μm, and is formed in an elliptical shape when viewed in a plane. The auxiliary support portion 4 is formed on a package body corresponding to a free end of a tuning fork type quartz vibrating element to be mounted, which will be described later, and corresponds to a position where the free end is likely to come into contact with a large-deflection package due to an external impact. It is formed.
[0026]
In addition, the thickness of the auxiliary support portion 4 is preferably 20 μm to 100 μm, and more preferably 30 μm to 80 μm, whereby improvement in impact resistance and stable electric characteristics can be obtained. .
[0027]
Such a film-like silicone resin is formed into a liquid having low thixotropy at a predetermined position on the package body or the lid, and is spread over the package body or the package body and the lid by discharging the silicone resin from the needle. By drying and curing this, a predetermined film-shaped auxiliary support portion can be formed relatively easily.
[0028]
As shown in FIG. 2, such an electronic component package joins the metal layer 11 on the upper surface of the bank and a metal film (not shown) formed on the lid 2 by heating means such as seam welding or beam welding. Then, the package is hermetically sealed. The lid 2 is formed by nickel plating on a metal base material such as Kovar or a brazing material such as silver brazing on a sealing surface.
[0029]
A configuration in which a tuning fork type piezoelectric vibration element is housed in such a package will be described with reference to FIGS. The tuning-fork type crystal vibrating element 3 includes a pair of vibrating arms 3b and 3c and a base 3a connecting these vibrating arms. A pair of excitation electrodes (not shown) are formed on the tuning-fork type quartz vibrating element so as to excite bending vibration, and an adjusting metal film 31 is provided on the free ends of the vibrating arms 3b and 3c. , 32 are formed. In the tuning-fork type quartz vibrating element 3, the characteristics are adjusted by performing an operation of increasing or decreasing the mass in the region of the adjustment metal films 31 and 32. In the present embodiment, the adjustment is performed by reducing the mass of the adjustment electrode 31 by the ion milling method. Note that a relatively thick metal film such as silver is formed in advance on the tip of the vibrating arm of the tuning-fork type quartz vibrating element 3 by a vacuum evaporation method, a sputtering method, an electroplating method, or the like.
[0030]
Such a tuning-fork type quartz vibrating element 3 is mounted in a cantilever manner so that a pair of electrodes formed on its base 3a and the internal connection electrodes 12 and 13 of the package 1 are connected. Join. The conductive bonding material S used here is a material obtained by adding a conductive filler to a silicone-based resin, and also has a shock absorbing function by a silicone elastic material. In such a state, a characteristic adjustment operation such as a frequency is performed. In performing the operation, first, a mask member made of, for example, a plate-like metal having an opening formed in a portion corresponding to the adjustment electrodes 31 and 32 is packaged. Close to. In this state, ion milling (ion etching) is performed to gradually reduce the adjustment metal film. At this time, a change in the characteristic to be adjusted may be monitored in real time, or if it is difficult, a desired characteristic may be obtained by alternately performing the adjustment operation and the characteristic measurement operation based on the adjustment.
[0031]
In the adjustment, the adjustment is performed by ion milling without using a reactive gas. However, ion etching using a reactive gas may be used, or a partial vapor deposition method that adds mass may be used. However, as is well known, when the mass is reduced, for example, in the frequency characteristics, the initial characteristics need to be lower than the desired frequency, and when the mass is added, the initial characteristics need to be higher than the desired frequency.
[0032]
After the necessary adjustments have been made, the lid is closed with the lid 2 in a vacuum atmosphere, and hermetically sealed by, for example, electron beam welding or seam welding in a vacuum atmosphere, and storing the tuning-fork type quartz vibrating element. The obtained piezoelectric vibration device can be obtained.
[0033]
A second embodiment according to the present invention will be described with reference to FIG. FIG. 6 is a cross-sectional view showing an internal structure showing an example in which a tuning fork type crystal resonator element is mounted on an electronic component package and hermetically bonded by a lid. This embodiment is different from the first embodiment in that a buffer portion is provided on the lid side, and the other points are substantially similar to the previous embodiment, so that a part of the description will be given. Omit.
[0034]
The electronic component package 1 has a rectangular parallelepiped shape as a whole, and has an electronic component element housing portion 1a that is concave when viewed in cross section. A bank portion 10 is formed around the electronic component storage section 1a, and a circumferential metal layer 11 is formed on the upper surface of the bank portion 10. Inside the electronic component package 1, internal connection electrodes 14 and 15 are formed at one end in the long side direction side by side in the short side direction, and a space one step lower is formed inside the package other than the internal connection electrodes. are doing.
[0035]
An auxiliary support portion 41 is formed on the other end of the electronic component package 1 in the long side direction, and the metal lid 2 that covers the electronic component housing portion 1a of the electronic component package also has a long side direction. A buffer 42 is formed on the other end. Each of the auxiliary support portion 41 and the buffer portion 42 is formed of a film-shaped silicone resin, and is disposed at a position corresponding to a free end portion of a tuning fork type quartz vibrating element to be housed.
[0036]
Both the electronic component package and the lid are prepared in a liquid having a low thixotropy and are spread over the package body or the lid by discharging the silicone resin from the needle. By drying and curing this, a predetermined film-shaped auxiliary support portion can be formed relatively easily.
[0037]
In this embodiment, as in the above-described embodiment, the electronic component element to be mounted uses a tuning-fork type quartz vibrating element, and the adjusting metal films 31 and 32 are formed at the free ends. The internal connection electrodes 12, 13 and the base of the tuning-fork type quartz vibrating element are electrically and mechanically bonded by a conductive bonding material (conductive silicone resin adhesive), cured, dried, and stabilized by annealing or the like. Then, it is air-tightly sealed with a lid having a buffer portion made of the silicone resin. Hermetic sealing is performed by, for example, seam welding, beam welding, or brazing by atmospheric heating.
[0038]
With the above configuration, the buffer portion made of silicone resin of the same base material as the conductive bonding material is formed on the package body and the lid side, so even if the package body or the lid is strongly hit, the silicone resin buffer function is used. In addition, the piezoelectric vibrating device is not damaged, and a part of the electrode material formed on the piezoelectric vibrating device does not peel off. This eliminates the problem that the characteristics such as frequency fluctuate due to the damage or peeling. Further, by using the same silicone resin as the base material of the conductive bonding material and the auxiliary support portion, it is possible to treat the basic characteristics of the resin, for example, the curing conditions or the exhaust conditions of the contained unnecessary gas, almost equally. Therefore, it is possible to obtain a low-cost piezoelectric vibration device with stable characteristics without requiring an extra manufacturing process.
[0039]
A third embodiment according to the present invention will be described with reference to FIG. FIG. 7 is a cross-sectional view showing an internal structure of an example in which a tuning fork type crystal resonator element is mounted on an electronic component package. In the present embodiment, the auxiliary support portions 43 and 44 are formed of the same conductive bonding material as that for bonding the tuning-fork type quartz vibrating element, and a configuration in which the conductive bonding material is divided is employed. Note that the other points are substantially similar to the previous embodiment, and thus a description thereof is partially omitted.
[0040]
Auxiliary support portions 43 and 44 are formed at the other end in the long side direction of the electronic component package. These auxiliary support portions 43 and 44 are made of the same material as the conductive bonding material for electrically and mechanically connecting the tuning fork type quartz vibrating element 3 to the package 2. It is made of a conductive bonding material S1. These auxiliary support portions 43 and 44 are formed corresponding to the respective vibrating arms 3b and 3c of the tuning fork type crystal vibrating element, and the electrodes formed on the vibrating arms are short-circuited via the auxiliary support portions 43 and 44. It is formed not to be.
[0041]
The tuning fork type quartz vibrating element having the excitation electrodes formed on the package on which the auxiliary support portions 43 and 44 are formed is mounted on the internal connection electrodes 14 and 15 of the package, and the conductive bonding material S1 is applied, followed by curing and annealing. To Thereafter, after performing necessary adjustments, the lid is closed with the lid 2 in a vacuum atmosphere, and hermetically sealed by, for example, electron beam welding or seam welding in a vacuum atmosphere, and storing the tuning-fork type quartz vibrating element. The obtained piezoelectric vibration device can be obtained.
[0042]
In each of the embodiments, an example has been described in which the elastic insulating film S1 is formed around the adjustment metal portion of the tuning-fork type quartz vibrating element, but the elastic insulating film S1 is formed in the entire vibrating arm portion or inside the package other than the internal connection electrodes. You may.
[0043]
In each of the above embodiments, a tuning fork type quartz vibrating element has been exemplified as an electronic component element, but another piezoelectric vibrating element such as an AT cut quartz vibrating element may be used.
[0044]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, while improving impact resistance, it can respond to microminiaturization and can obtain the piezoelectric vibration device which can be manufactured efficiently.
[Brief description of the drawings]
FIG. 1 is a plan view showing a first embodiment.
FIG. 2 is an internal cross-sectional view showing the first embodiment.
FIG. 3 is a bottom view showing the first embodiment.
FIG. 4 is a plan view showing the first embodiment.
FIG. 5 is an internal cross-sectional view showing the first embodiment.
FIG. 6 is an internal sectional view showing a second embodiment.
FIG. 7 is a plan view showing a third embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Electronic component package 12, 13, 14, 15 Internal connection electrode 121, 131, 141, 151 External connection electrode 10 Embankment 2 lid 12a, 14a Dummy electrode 13a, 15a Extraction electrode 4, 41, 42, 43, 44 Auxiliary Support

Claims (5)

A package main body having a rectangular shape in plan view made of an insulating material, a plurality of electrode connecting portions formed in parallel on one end side in the long side direction of the package main body, and one end supported by a conductive bonding material at the electrode connecting portions. A piezoelectric vibrating element on which an excitation electrode is formed, an auxiliary support formed below the other end of the piezoelectric vibrating element and on the other end in the long side direction of the package body, and hermetically bonded to the package body. A piezoelectric vibrating device comprising:
A piezoelectric vibrating device, wherein the base material of the conductive bonding material and the auxiliary support portion is made of a silicone resin. The piezoelectric vibrating element is a tuning-fork type piezoelectric vibrating element including a pair of vibrating arms and a base connecting the vibrating arms, and a metal film region for frequency adjustment is formed at a free end of each vibrating arm. 2. The piezoelectric vibration device according to claim 1, wherein the auxiliary support portion is formed at least below the metal film region in a cantilever support configuration in which the base portion is joined to the electrode connection portion. 3. The piezoelectric vibration device according to claim 1, wherein a buffer portion made of a silicone resin is formed in a lid portion located above the other end of the piezoelectric vibration element. 4. The piezoelectric vibration device according to claim 1, wherein the auxiliary support portion has a film-like configuration made of only a silicone resin. The piezoelectric device according to any one of claims 1 to 4, wherein the height of the auxiliary support portion formed on the package body is １ ／ to の of the height of the electrode connection portion. Vibration device.

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