JP2009005117A - Surface-mounting type piezoelectric vibration device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact surface-mounting type piezoelectric vibration device having more stable temperature characteristics and higher reliability. <P>SOLUTION: The surface-mounting type piezoelectric vibration device housing a piezoelectric diaphragm 2 with an exciting electrode in a container of a rectangular shape in plane view, configured by covering a ceramic package 1 with a cover 5, comprises: a heater 3 for heating the piezoelectric diaphragm in the container; and a sensor 4 for detecting the temperature inside the container. Wherein, the heater is formed in the ceramic package and one or more heat conduction parts 12, 13 thermally connected with the heater for heating the piezoelectric diaphragm in the container are formed at each of side walls corresponding to sides of the container. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a surface-mount type piezoelectric vibration device with a thermostatic chamber.

  As shown in Patent Documents 1 and 2, a piezoelectric vibration device with a thermostatic chamber has been conventionally used in which the frequency is stabilized by controlling the temperature of the piezoelectric vibrator in the thermostatic chamber without affecting external temperature changes. Existing. In such a piezoelectric vibrating device with a thermostatic chamber, the highest frequency stability obtained with a piezoelectric vibrator of about 1 × 10 −7 to 1 × 10 −10 can be obtained as the frequency stability. Used as a reference frequency for transmission lines. Such a piezoelectric vibrating device with a thermostatic chamber constitutes a thermostatic chamber by attaching a heating means and a sensor to a piezoelectric vibrator hermetically sealed as a single unit, and separates the thermostatic chamber from other circuit components. Since the final container is obtained by mounting on the substrate and covering the lid, there is a problem that the size is increased as compared with other piezoelectric vibrating devices. In a large container, since the temperature mass for maintaining the temperature also decreases, there is a concern that the power consumption required for heating will increase as a result.

Even in the field of the piezoelectric vibration device with a thermostat, there is a demand for further miniaturization, and a piezoelectric vibration device as shown in Patent Document 3 has been proposed. That is, a heating means such as a ceramic heater is integrally formed on a container made of a ceramic laminated substrate, and a piezoelectric component such as a piezoelectric diaphragm and an oscillation circuit component are accommodated in the container configured in this manner. A configuration having a small size has been proposed.
JP-A-2-305004 JP 2002-223122 A JP 2003-224422 A

  However, in the piezoelectric vibration device disclosed in Patent Document 3, the temperature distribution inside the container is likely to vary, and as a result, there is a concern that the accuracy during the constant temperature control also varies and affects the frequency stability. . That is, only the bottom surface side of the container where the ceramic heater is present is heated inside the container, so that not only a temperature difference occurs between the piezoelectric parts, sensors, or other oscillation circuit parts arranged inside the container, On the upper surface side of the container farthest from the ceramic heater, it is easily affected by the external environmental temperature. In other words, the temperature distribution inside the container varies, and the temperature gradient inside the container may change depending on the ambient temperature. In particular, in the case of a ceramic laminated substrate container, the heat conduction efficiency and heat followability of the material itself are poor compared to conventional metal containers, and thus the above-described problems are more likely to appear. As a result, there has been a problem in that the accuracy of the temperature characteristics of the piezoelectric vibrating device with a thermostatic chamber is hindered.

  The present invention has been made in view of the above points, and an object of the present invention is not only to realize downsizing, but also to obtain a more stable temperature characteristic and a more reliable surface mount type piezoelectric vibration. To provide a device.

  In order to achieve the above object, the present invention can be realized by the following configuration.

  That is, as shown in claim 1, there is provided a surface mount type piezoelectric vibration device in which a piezoelectric diaphragm having an excitation electrode formed therein is accommodated in a rectangular container in plan view formed by covering a ceramic package with a lid, A heater for heating the piezoelectric diaphragm inside the container and a sensor for detecting the internal temperature of the container are formed. The heater is formed in the ceramic package, and is thermally connected to the heater to heat the piezoelectric diaphragm inside the container. One or more heat transfer portions are formed on each side wall corresponding to each side of the container.

  According to claim 1, a heater for heating the piezoelectric diaphragm inside the container and a sensor for detecting the internal temperature of the container are provided, the heater is formed in the ceramic package, and the container is thermally connected to the heater. Since one or more heat transfer parts for heating the piezoelectric diaphragm are formed on the side walls corresponding to the sides of the container, a drastic downsizing and low profile can be achieved using a container with a lid on a ceramic package. Thus, a surface mount type piezoelectric vibration device in which the function of the thermostatic bath is added can be obtained. In addition, since the heat of the heater is propagated and heated throughout the interior of the container by the heat transfer section, it is not affected by the temperature of the external environment, and the temperature accuracy when controlling the temperature without affecting the temperature distribution inside the container Can also be increased. Further, since the heat transfer part is provided on the side wall of the ceramic package, heat radiation from the side wall of the ceramic package can be suppressed, and the constant temperature control inside the container becomes easy. As a result, it is possible to provide a more reliable surface-mount type piezoelectric vibration device that not only achieves miniaturization but also provides more stable temperature characteristics.

  According to a second aspect of the present invention, there is provided a lid having a high thermal conductivity thermally connected to the heat transfer section, or a lid formed with a heat conductive film thermally connected to the heat transfer section. It is characterized by that.

  According to the second aspect, in addition to the above-described effects, the lid can be provided with a heating function as an auxiliary heater. In other words, the heat inside the container can be more uniformly propagated and heated by the heat transfer section and the lid so that the temperature distribution inside the container is not affected by the external environment temperature. In addition, the temperature accuracy during the constant temperature control can be dramatically improved. By using a metal member or the like as the lid having high thermal conductivity, an inexpensive auxiliary heater with high heating efficiency can be obtained. In the case of the lid having low thermal conductivity, an inexpensive auxiliary heater having a high degree of design freedom can be obtained by forming a thermal conductive film by metallization technology or thick film printing technology. In particular, the lid and heat transfer part of these metal members, or the heat conductive film and heat transfer part of the lid are joined to each other by welding or brazing so that no loss in heat propagation occurs. preferable.

  In each configuration described above, the lid may be formed of a multilayer member, and the outer surface side member layer may be made of a material having lower thermal conductivity than the inner surface side member layer. Thereby, heating to the inside of the container can be promoted by the member layer on the inner surface side having high heat conductivity while blocking or suppressing heat radiation to the outside of the container by the member layer on the outer surface side having low heat conductivity. Therefore, heating efficiency can be increased and power saving can be realized. For example, when the lid is made of a metal member, a clad member in which a copper member (about 403 W / m · K, 0 ° C.) is laminated inside a kovar member (about 19.7 W / m · K, room temperature) is used. Good. When the lid is composed of a ceramic member (about 12 W / m · K, room temperature), tungsten (about 177 W / m · K, 0 ° C) or molybdenum (about 139 W / m · K, 0 ° C) against the ceramic package It is sufficient to form a metallized member such as Au plating (about 319 W / m · K, 0 ° C.), and more preferably, a metal film having high thermal conductivity is formed on the upper surface of the metallized member. Moreover, you may form a copper thick film printing member (about 403 W / m * K, 0 degreeC) with respect to a ceramic package or a glass package (about 0.55-0.75 W / m * K, room temperature).

  According to a third aspect of the present invention, in addition to the above-described configuration, the heater is made of a film resistor.

  According to the third aspect, in addition to the above-described effects, the heater is made of a film resistor, so that the degree of freedom in mounting the heater on the ceramic package and the reduction in height are dramatically improved by utilizing the metallization technique. Further, since there is no need to route the heater wire unlike a ceramic heater, the wiring can be made thinner and easier.

  According to a fourth aspect of the present invention, in addition to the above-described configuration, an integrated circuit element constituting a piezoelectric oscillation circuit using the piezoelectric diaphragm as an oscillator is housed in a ceramic package, and a heater is integrated with the integrated circuit element. It is structured.

  According to the fourth aspect, in addition to the above-described effects, the integrated circuit element is integrally formed with the heater, thereby reducing the number of parts, realizing a reduction in size and height, and saving power. In particular, it is known that an integrated circuit element when it is energized and oscillates alone generates heat to a high temperature, and simultaneously uses the heat generated by the integrated circuit element itself and the heat generated by the heater incorporated in the integrated circuit element. As a result, the heating efficiency is dramatically increased, and heating can be performed in a shorter time and with less power consumption. In addition, since the integrated circuit element is disposed in only one place of the container as the heating start region, the heating elements are dispersed as compared with the configuration in which the integrated circuit element and the heater are disposed in different positions of the container. In this way, fluctuations in the temperature gradient inside the container can be reduced. As a result, the temperature characteristics can be easily adjusted, and more stable temperature characteristics can be obtained. In addition, since the temperature of the integrated circuit element can be maintained at a constant temperature, more stable temperature characteristics can be obtained.

  In addition to the structure of the above-mentioned claim 4, a sensor for detecting the internal temperature of the container may be integrated with the integrated circuit element. As a result, the number of parts can be reduced, and further miniaturization and height reduction and power saving can be realized.

  According to a fifth aspect of the present invention, in addition to the above configuration, a mounting portion that supports the piezoelectric diaphragm is formed on the upper surface of the ceramic package, and a sensor is disposed directly below the mounting portion. Features.

  According to the fifth aspect, in addition to the above-described effects, a mounting portion that supports the piezoelectric diaphragm is formed on the upper surface of the ceramic package, and a sensor is disposed directly below the mounting portion, thereby Since the temperature management can be performed in the state closest to the piezoelectric diaphragm without hindering the vibration of the diaphragm, the temperature accuracy during the constant temperature control can be further increased.

  In each of the above-described configurations, the heat transfer portion provided on the ceramic package or the side wall of the lid may be configured by a metallized member formed inside a through hole or castellation. Thereby, a heat transfer part can be comprised very easily and cheaply using the ceramic lamination | stacking technique and metallization technique.

  In each configuration described above, the heat transfer portion provided on the side wall of the ceramic package or the lid may be configured by a through hole or a bulk member made of copper or aluminum formed inside the castellation. Thereby, a heat-transfer part with very high heat conductivity and high heating efficiency can be comprised.

  According to the present invention, it is possible to provide a more reliable surface-mount type piezoelectric vibration device that not only achieves downsizing but also provides more stable temperature characteristics.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. A first embodiment of the present invention will be described with reference to FIGS. 1 and 2 by taking a surface-mount piezoelectric vibrator as an example. FIG. 1 is a sectional view showing a first embodiment of the present invention. FIG. 2A is a plan view of FIG. 1, and FIG. 2B and FIG. 2C are plan views showing a modification of FIG.

  The surface-mount piezoelectric vibrator includes a ceramic substrate (ceramic package) 1 having a recess with an upper opening, a piezoelectric diaphragm 2 housed in the ceramic substrate, a heater 3 for heating the piezoelectric diaphragm, It comprises a sensor 4 that detects the temperature of the heater and a lid 5 that is joined to the opening of the ceramic substrate.

  The ceramic substrate 1 is a rectangular parallelepiped as a whole, and has a configuration in which a ceramic such as alumina and a conductive material such as tungsten or molybdenum are appropriately laminated, and has a concave storage portion 10 when viewed in cross section. A bank 11 is formed around the storage section, and the upper surface of the bank 11 is flat, and a sealing member and a metal layer (not shown) are formed on the bank. In this embodiment, for example, each of a nickel plating layer and a gold plating layer is formed on the upper surface of a metallized layer made of tungsten, molybdenum or the like as a metal layer.

  Inside the ceramic substrate 1, a holding base 10a for holding an end portion of a piezoelectric diaphragm 2 described later, and a wiring pattern (not shown) connected to the piezoelectric diaphragm are formed on the upper surface of the holding base 10a. The wiring patterns are respectively drawn out as input / output terminals to external connection terminal electrodes (not shown) formed on the lower surface of the ceramic substrate on the opposite surface by conductive vias or castellation (not shown). The ceramic substrate having such a structure is formed by using a known ceramic lamination technique or metallization technique, and the wiring pattern is a structure in which a nickel plating layer and a gold plating layer are formed on the upper surface of the metallization layer made of tungsten, molybdenum, or the like. .

  A piezoelectric diaphragm 2 is mounted above the wiring pattern. The piezoelectric diaphragm 2 is a quartz diaphragm such as an AT cut or an SC cut in which an excitation electrode and an extraction electrode (not shown) are formed. These electrodes can be formed by a thin film forming means such as a vacuum deposition method or a sputtering method. it can. The piezoelectric diaphragm 2 and the ceramic substrate 1 are joined to the wiring pattern electrically and mechanically through a conductive bonding material such as a metal bump, a brazing material, or an adhesive (not shown).

  The lid 5 that hermetically seals the ceramic substrate is made of a metal member, a ceramic member, a glass member, a crystal member, or the like, and materials are properly used depending on the sealing structure. In the present embodiment, for example, a metal member having a sealing material such as a metal brazing material formed on a core material made of Kovar or the like is used. More specifically, for example, it is a multilayer structure in the order of a nickel layer, a kovar core material, a copper layer, and a gold plating layer from the upper surface, and the gold plating layer is bonded to the metal layer of the ceramic substrate. The outline of the lid 5 in plan view is substantially the same as or slightly smaller than the outline of the ceramic substrate 1. In addition, in the case of a metal member, you may comprise not only gold plating but other sealing brazing materials.

  The piezoelectric diaphragm 2 is stored in the storage portion 10 of the ceramic substrate 1 and covered with the lid 5 for hermetic sealing. In the present embodiment, since the gold plating layer on the upper surface of the bank portion of the ceramic substrate 1 and the gold plating layer of the lid 5 are hermetically sealed by thermal diffusion bonding, molten gas such as brazing material is generated. It realizes hermetic sealing of piezoelectric vibration devices with no higher stability and accuracy. In addition, the sealing form of the lid made of a metal member is not limited to gold thermal diffusion bonding, but is sealed by seam welding, sealing by beam welding such as laser or electron beam, or atmosphere heating by sealing a brazing filler metal such as gold tin. It may be sealed. However, in the hermetic sealing of the piezoelectric vibration device for high stability and high accuracy, it is preferable to perform the degassing.

  In the present invention, a heater 3 for heating the piezoelectric diaphragm 2 inside the container composed of the ceramic substrate 1 and the lid 5 as described above and a sensor 4 for detecting the internal temperature of the container are provided. The first heat transfer section 12 that forms a heater 3 and is thermally connected to the heater 3 and heats the piezoelectric diaphragm 2 inside the container is provided between the bottom surface of the ceramic substrate, the internal surface, and the stack of ceramic substrates. The second heat transfer section 13 that is formed in any of the above and is thermally connected to the first heat transfer section 12 and heats the piezoelectric diaphragm 2 inside the container is provided on the side wall corresponding to each side of the container. A characteristic configuration is that one or more of each is formed. Hereinafter, the features of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the heater 3 is formed by printing a film resistor such as a thick film printing resistor, and is formed between the ceramic substrates 1 together with the first heat transfer portion 12 made of a metallized member or the like. . The heater 3 and the first heat transfer section 12 by this film resistor can be formed on either the bottom surface of the ceramic substrate or the internal surface (the top surface of the storage portion), without being limited to the lamination of the ceramic substrates 1. . The first heat transfer section 12 is drawn out to the area of the four sides of the bank 11, and one or more of the first heat transfer sections 12 are formed on the bank of each side and are thermally applied to the second heat transfer section 13 made of a metallized member or the like. It is connected to the. For example, the second heat transfer section 13 of the present embodiment is configured by a plurality of vias penetrating vertically inside the bank portion of each side as shown in FIG. By configuring the second heat transfer section inside the bank portion, thermal loss to the outside of the container can be suppressed, and design of various wiring patterns inside the container can be prevented.

  In addition, the 2nd heat-transfer part 13 is comprised on the surface of the several castellation which extends the outer end part of the bank part of each side to an up-down direction as shown in FIG.2 (b), or FIG.2 (c). ), The inner end of the bank portion on each side may be formed on the surface of one wide castellation that extends in the vertical direction. Furthermore, you may comprise combining any two or more of the inside of an embankment part, an outer end, and an inner end. It is desirable that the second heat transfer section has a surface area as large as possible and is arranged inside the container because heat radiation can be reduced. In particular, in FIG. 2 (c), since the wide second heat transfer portion is formed at the inner end of the bank portion on each side, thermal loss to the outside of the container can be suppressed, and Heating efficiency can be maximized.

  The first heat transfer section 12 and the second heat transfer section 13 are made of a metallized member such as tungsten or molybdenum, and can be formed by a metallization technique utilizing a thick film printing technique or a ceramic lamination technique. it can. In addition, the metallized material of each heat transfer part may be changed to a material having a high heat transfer effect such as copper or gold, or may contain a material having a high heat transfer characteristic such as aluminum or silver. A metal film having a high heat transfer effect, such as gold or copper, may be laminated on the upper surface.

  The sensor 4 is composed of, for example, a chip-type thermistor, and is closely attached to the concave portion 14 on the bottom surface side of the ceramic substrate 1. The sensor 4 is made of the heat conductive resin N such as silicone resin or epoxy resin having high heat conductivity. And a part of the recess 14 are formed as a film. For this reason, the influence of the fluctuation | variation of ambient environment temperature can be suppressed and the more accurate temperature detection which eliminated the temperature difference inside a container can be performed. In addition, as shown in FIG. 3, it is more preferable that the sensor 4 is disposed directly below the ceramic substrate holding base 10a (the mounting portion that supports the piezoelectric diaphragm). Since the temperature management can be performed in the state closest to the piezoelectric diaphragm 2 without hindering the vibration of the piezoelectric diaphragm 2, the temperature accuracy during the constant temperature control can be further increased.

  In the embodiment of the present invention, in addition to these configurations, the second heat transfer section 13 is exposed on the upper surface of the bank 11, and the silver brazing material is melt-bonded at the time of hermetic sealing so that the metal member The lid 5 is made of metal-to-metal bonding and thermally connected. In other words, the piezoelectric diaphragm 2 inside the container can be heated by transferring the heat of the second heat transfer section 13 to the metal member lid 5 having high thermal conductivity. In this embodiment, the lid 5 of the metal member is made of a multilayer member, and a copper layer is formed inside the container of the core material made of, for example, Kovar. That is, the Kovar member layer on the outer surface side (about 19.7 W / m · K, room temperature) is made of a material having lower thermal conductivity than the copper member layer on the inner surface side (about 403 W / m · K, 0 ° C.). As a result, while the Kovar member layer on the outer surface side with low thermal conductivity blocks or suppresses heat radiation to the outside of the container, heating to the inside of the container is promoted with the copper member layer on the inner surface side with high thermal conductivity. be able to. As a result, heating efficiency can be increased and power saving can be realized. As described above, the surface mount type piezoelectric vibrator (surface mount type piezoelectric vibration device) according to the present embodiment is completed.

  According to the first embodiment of the present invention, a drastic reduction in size and height is realized using a container in which a ceramic substrate 1 having a storage portion is covered with a lid 5, and the function of a thermostatic bath is added. A surface-mount type piezoelectric vibration device is obtained. In addition, since the heat of the heater 3 can be uniformly propagated and heated throughout the container by the first heat transfer section 12, the second heat transfer section 13, and the lid 5, it is affected by the external environment temperature. In addition, the temperature accuracy during the constant temperature control can be drastically increased without giving variation to the temperature distribution inside the container. In addition, since the heater 3 is made of a membrane resistor, the degree of freedom in mounting the heater 3 on the ceramic substrate 1 and the reduction in height are dramatically improved.

  FIG. 4 shows a modification of the embodiment of the present invention. In this modification, the heater 3 made of a chip resistor is used without being limited to a heater using a film resistor. A heater 3 made of a chip resistor is disposed in close contact with the concave portion 14 on the bottom surface side of the ceramic substrate 1, and is surrounded by the heat conductive resin N such as silicone resin or epoxy resin having high heat conductivity. A film is formed on a part of the recess 14. For this reason, the influence of the fluctuation | variation of ambient environment temperature can be suppressed, a more extensive and uniform heating can be implement | achieved, and the fluctuation | variation of the temperature gradient inside a container can be reduced.

  In addition, in the modification of FIG. 4, the lid 5 for hermetically sealing the ceramic substrate is made of a lid with low thermal conductivity such as a ceramic member or a glass member. Thus, the heat conductive film 51 is configured. For example, when the lid 5 is formed of a ceramic member (about 12 W / m · K, room temperature), tungsten (about 177 W / m · K, 0 ° C.) or molybdenum (139 W / m · K) with respect to the lid of the ceramic substrate. A metallized member such as Au or the like may be formed. More preferably, a metal film having high thermal conductivity such as Au may be formed on the upper surface of the metallized member. Moreover, you may form a copper thick film printing member (about 403 W / m * K, 0 degreeC) with respect to a ceramic substrate or a glass substrate (about 0.55-0.75 W / m * K, room temperature).

  Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a sectional view showing a second embodiment of the present invention. In addition, the same part as the said 1st Embodiment attaches | subjects the same number, and omits a part of description.

  Surface-mount type piezoelectric oscillator, ceramic substrate (ceramic package) 1 having a recess with an opening at the top, integrated circuit element 6 housed in the ceramic substrate, and piezoelectric vibration housed in the top of the ceramic substrate It consists of a plate 2, a heater 3 for heating the piezoelectric diaphragm, a sensor 4 for detecting the temperature of the heater, and a lid 5 bonded to the opening of the ceramic substrate.

  The ceramic substrate 1 is a rectangular parallelepiped as a whole, and has a configuration in which a ceramic such as alumina and a conductive material such as tungsten or molybdenum are appropriately laminated, and has a concave storage portion 10 when viewed in cross section. The storage unit 10 is formed with a first storage unit 10b on the lower side and a second storage unit 10c on the upper side. The upper surface of the bank 11 is flat, and a sealing member and a metal layer (not shown) are formed on the bank.

  Inside the ceramic substrate 1, as described above, the first storage portion 10 b that stores the integrated circuit element 6 and the holding base 10 a that holds one end of a piezoelectric diaphragm described later are formed on the lower surface. A second storage portion 10c for storing the piezoelectric diaphragm 2 mounted on the holding base 10a is formed above the storage portion 10b.

  Inside the ceramic substrate 1, a wiring pattern (not shown) connected to the piezoelectric diaphragm 2 is formed on the upper surface of the holding table 10a, and an integrated circuit element 6 and a later-described integrated circuit element 6 are formed on the upper surface portion of the first storage portion 10b. A wiring pattern (not shown) to be connected and the first heat transfer section 12 are formed. The first heat transfer section 12 is drawn out to the area of the four sides of the bank 11, and one or more of the first heat transfer sections 12 are formed on the bank of each side and are thermally applied to the second heat transfer section 13 made of a metallized member or the like. It is connected to the. The second heat transfer section 13 of the present embodiment can be obtained, for example, by configuring it with one or more vias that vertically penetrate the inside of each bank. The wiring patterns are connected as necessary by conductive vias or castellation (not shown), and are led out as input / output terminals to external connection terminal electrodes (not shown) formed on the lower surface of the ceramic substrate. These wiring patterns, the first heat transfer section 12 and the second heat transfer section 13 are made of a metallized member such as tungsten or molybdenum, for example, and metallization utilizing a thick film printing technique or a ceramic lamination technique. It can be formed by technology. In addition, the wiring pattern is a structure in which each layer of a nickel plating layer and a gold plating layer is formed on the upper surface of the metallized layer, and each heat transfer part is changed to a metallized material with a high heat transfer effect material such as copper or gold, A material having a high heat transfer property such as aluminum or silver may be contained, and a metal film having a high heat transfer effect such as gold or copper may be laminated on the upper surface of the first heat transfer portion.

  The integrated circuit element 6 mounted in the lower housing part is a one-chip integrated circuit element that constitutes an oscillation circuit together with the piezoelectric diaphragm 2 and has a rectangular parallelepiped shape as a whole. A plurality of connection terminals (not shown) are formed on the lower active circuit surface. The heater 3 is made of a film resistor such as a thin film printing resistor and is formed on the inactive surface side of the IC together with a necessary wiring pattern (not shown). The sensor 4 is formed of a thermistor or the like and is formed in a part of the IC. The plurality of wiring patterns of the ceramic substrate 1 and the connection terminals of the integrated circuit element 6 are joined by electromechanical joining by a well-known face-down bonding technique. An underfill made of an insulating resin material may be formed between the bottom surfaces of the one storage portion 10b. By forming the underfill, the mechanical joint strength of the integrated circuit element 6 can be improved.

  Above the integrated circuit element 6, the piezoelectric diaphragm 2 is mounted on the holding table 10a with a predetermined interval.

  The lid 5 for hermetically sealing the ceramic substrate is made of a metal member, a ceramic member, a glass member, or the like, and the material is properly used depending on the sealing structure. In the present embodiment, for example, a metal member having a sealing material such as a metal brazing material formed on a core material made of Kovar or the like is used. More specifically, for example, it is a multilayer structure in the order of a nickel layer, a kovar core material, a copper layer, and a silver brazing layer from the upper surface, and the silver brazing layer is joined to the metal layer of the ceramic substrate.

  The integrated circuit element 6 and the piezoelectric diaphragm 2 are housed in the storage portion 10 of the ceramic substrate 1 and covered with the lid 5, and the sealing material of the lid is melt-cured to perform hermetic sealing. In the present embodiment, airtight sealing is performed by seam welding without using a metal ring for sealing, and the seam roller runs along the ridges of the long side and the short side of the metal lid, The silver brazing formed on the metal plate and the metal layer of the ceramic substrate are welded to perform hermetic sealing. In addition, the sealing form of the lid made of a metal member is not limited to seam welding, but may be sealing by beam welding such as laser or electron beam or atmosphere heating sealing by sealing a brazing material such as gold tin. Good.

  In the embodiment of the present invention, in addition to these configurations, the heat transfer portion 13 is exposed on the upper surface of the bank, and the lid 5 made of a metal member is obtained by melting and joining the silver brazing material during hermetic sealing. Are joined to each other and thermally connected. That is, the piezoelectric diaphragm 2 inside the container can be heated by the heat of the second heat transfer section 13 being transferred to the lid 5 of the metal member having high thermal conductivity. In this embodiment, the lid 5 of the metal member is made of a multilayer member, and a copper layer is formed inside the container of the core material made of, for example, Kovar. That is, the Kovar member layer on the outer surface side (about 19.7 W / m · K, room temperature) is made of a material having lower thermal conductivity than the copper member layer on the inner surface side (about 403 W / m · K, 0 ° C.). As a result, while the Kovar member layer on the outer surface side with low thermal conductivity blocks or suppresses heat radiation to the outside of the container, heating to the inside of the container is promoted with the copper member layer on the inner surface side with high thermal conductivity. be able to. As a result, heating efficiency can be increased and power saving can be realized. As described above, the surface-mounted piezoelectric oscillator (surface-mounted piezoelectric vibrating device) according to the present embodiment is completed.

  In the second embodiment, the IC having the heater 3 and the sensor 4 incorporated therein is described. However, the sensor may be separately attached to the ceramic substrate. For example, you may attach separately to the bottom part of a ceramic substrate, or the inside of a ceramic substrate.

  According to the second embodiment of the present invention, a surface mount type piezoelectric device in which a drastic downsizing and low profile is realized by using a container having a lid 5 on a ceramic substrate 1 and the function of a thermostatic chamber is added. A vibrating device is obtained. In addition, since the heat of the heater 3 can be uniformly propagated and heated throughout the container by the first heat transfer section 12, the second heat transfer section 13, and the lid 5, it is affected by the external environment temperature. In addition, the temperature accuracy during the constant temperature control can be drastically increased without giving variation to the temperature distribution inside the container. In addition, since the heater 3 is made of a membrane resistor, the degree of freedom in mounting the heater 3 on the ceramic substrate 1 and the reduction in height are dramatically improved. In addition, by incorporating a film resistor into the integrated circuit element 6 and functioning as the heater 3, the number of components can be reduced, and miniaturization and power saving can be realized. In particular, it is known that an integrated circuit element, when energized and oscillated, alone generates heat to a high temperature, and the integrated circuit element itself and the film resistor incorporated in the integrated circuit element simultaneously generate heat. By using it, the heating efficiency is remarkably increased, and heating with shorter time and power saving becomes possible. In addition, since the integrated circuit element 6 is disposed at only one location of the container as a heating start region, the heating element is compared with a configuration in which the integrated circuit element 6 and the heater 3 are disposed at different positions of the container. Is not dispersed, and fluctuations in the temperature gradient inside the container can be reduced. As a result, the temperature characteristics can be easily adjusted, and more stable temperature characteristics can be obtained. Furthermore, since the sensor 4 for detecting the internal temperature of the container is also integrated with the integrated circuit element 6, the number of parts can be reduced, and further miniaturization and power saving can be realized.

  In the embodiment described above, the heat of the heater 3 is also transmitted to the lid 5 to heat the piezoelectric diaphragm 2 inside the container, but the lid 5 does not necessarily have to have a heating function. In addition, the heat of the heater 3 is transmitted to the lid itself or the heat conduction film formed on the lid to heat the piezoelectric diaphragm 2 inside the container, but the heater 5 is added to the lid 5 It may be. Moreover, although what formed by metallization as said 2nd heat-transfer part 13 was demonstrated, the bulk member which consists of a through hole provided in the side wall of the ceramic substrate 1 or the lid | cover 5, or a copper or aluminum inside a castellation is demonstrated. You may embed and constitute. With this configuration, it is possible to obtain a heat transfer section with extremely high heat transfer and high heating efficiency. Although the first heat transfer portion 12 formed by metallization has been described, a thick film having high thermal conductivity such as copper or aluminum may be printed.

  The present invention can be implemented in various other forms without departing from the spirit or main features thereof, and should not be interpreted in a limited manner. The scope of the present invention is indicated by the claims, and is not limited by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

It is sectional drawing which shows the 1st Embodiment of this invention. It is a top view which shows the top view of FIG. 1, and its modification. It is sectional drawing which shows the modification of the 1st Embodiment of this invention. It is sectional drawing which shows the modification of the 1st Embodiment of this invention. It is sectional drawing which shows the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ceramic substrate 2 Piezoelectric diaphragm 3 Heater 4 Sensor 5 Lid 6 Integrated circuit element

Claims (5)

A surface-mount type piezoelectric vibration device in which a piezoelectric vibration plate in which an excitation electrode is formed is contained in a rectangular container in plan view formed by covering a ceramic package with a lid,
A heater for heating the piezoelectric diaphragm inside the container, and a sensor for detecting the internal temperature of the container;
A heater is formed in the ceramic package, and one or more heat transfer portions that are thermally connected to the heater and heat the piezoelectric diaphragm inside the container are formed on each side wall corresponding to each side of the container. Surface mount type piezoelectric vibration device. 2. A lid having a high thermal conductivity thermally connected to the heat transfer section, or a lid formed with a heat conductive film thermally connected to the heat transfer section. The surface-mounted piezoelectric vibration device described. 3. The surface-mount type piezoelectric vibration device according to claim 1, wherein the heater is made of a film resistor. An integrated circuit element constituting a piezoelectric oscillation circuit using the piezoelectric diaphragm as an oscillator is housed in a ceramic package, and a heater is integrally formed with the integrated circuit element. Item 3. The surface-mount type piezoelectric vibration device according to Item 2. 5. The surface mounting according to claim 1, wherein a mounting portion for supporting the piezoelectric diaphragm is formed on an upper surface of the ceramic package, and the sensor is disposed directly below the mounting portion. Type piezoelectric vibration device.

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