JP2015220586A - Board for mounting piezoelectric vibration element and piezoelectric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a board for mounting a piezoelectric vibration element capable of reducing the difference between the temperature of the external environment of a board for mounting a piezoelectric vibration element housing a piezoelectric vibration element and a thermistor element and the temperature information sensed by the thermistor element, and achieving a lower profile, and to provide a piezoelectric device.SOLUTION: A board for mounting a piezoelectric vibration element includes an insulating base material 101 having a first base 115, having a mounting part 102 of a piezoelectric vibration element 105, and a through portion 103 penetrating from the upper surface to the lower surface of the mounting part 102, and in which a thermistor element 106 is housed, and a second base 116 arranged on the lower surface of the first base 115 so as to close the lower end of the through portion 103, a pair of connection conductors 107 provided on the mounting part 102, a pair of side face conductors 108 provided on the inner side face of the through portion 103, and a pair of through conductors 114 provided from the lower end of the pair of side face conductors 108 to the lower surface of the first base 115.

Description

  The present invention relates to a piezoelectric vibration element mounting substrate and a piezoelectric device for hermetically housing a piezoelectric vibration element such as a crystal.

  2. Description of the Related Art Conventionally, as a piezoelectric vibration element mounting substrate for accommodating a piezoelectric vibration element in an airtight manner, a substrate using an insulating base having a concave mounting portion in which the piezoelectric vibration element is accommodated is frequently used. A lid is bonded to the insulating base so as to close the mounting portion, and the piezoelectric vibration element is hermetically sealed in the mounting portion. A piezoelectric vibration element is hermetically sealed in a container composed of a mounting portion of an insulating base and a lid, thereby forming a piezoelectric device.

  Temperature compensation is performed because the oscillation frequency of the piezoelectric vibration element is highly temperature dependent. In recent years, a thermistor element is provided in the vicinity of the piezoelectric vibration element for more accurate temperature compensation of the piezoelectric vibration element accommodated in the mounting portion. An on-board piezoelectric device has been proposed.

  Note that the piezoelectric vibration element mounting substrate used in such a piezoelectric device has, for example, a two-stage bottom surface portion of the top mounting portion. Among them, the thermistor element is mounted on the lower side. A piezoelectric vibration element is mounted on the upper side. Since the piezoelectric vibration element and the thermistor element are mounted in the same container, a piezoelectric device whose positions are close to each other can be manufactured.

  In the piezoelectric vibration element mounting substrate and the piezoelectric device, an external connection terminal electrically connected to each of the electrode of the piezoelectric vibration element and the electrode of the thermistor element is provided on the lower surface of the insulating base ( Reference 1).

JP 2008-205938

  In recent years, the piezoelectric vibration element mounting substrate and the piezoelectric device according to the related art have been required to have higher temperature compensation accuracy, for example, for higher accuracy of equipment on which the piezoelectric device is mounted. ing.

  Specifically, for example, even when the piezoelectric vibration element and the thermistor element are mounted in the same container, the temperature of the external environment is transferred to the thermistor element in the container by heat conduction through an insulating substrate or the like. A time lag occurs. Therefore, it is difficult to accurately obtain the temperature of the actual external environment as the temperature information (change in resistance value) of the thermistor element.

  The piezoelectric vibration element mounting substrate according to one aspect of the present invention has an upper surface including a mounting portion of the piezoelectric vibration element and a lower surface opposite to the upper surface, and penetrates from the upper surface to the lower surface, and the thermistor. An insulating base having a first base having a penetrating portion that accommodates an element, and a second base disposed on the lower surface of the first base so as to close the lower end of the penetrating portion, and provided on the mounting portion A pair of connection conductors, a pair of side conductors provided on the inner side surface of the through portion, and a pair of through conductors provided from the lower end of the pair of side surface conductors to the lower surface of the first base portion. It is characterized by that.

  A piezoelectric device according to an aspect of the present invention includes the piezoelectric vibration element mounting substrate having the above-described configuration, a piezoelectric vibration element mounted on the mounting portion, and a thermistor element accommodated in the through portion. To do.

  According to the piezoelectric vibration element mounting substrate of one aspect of the present invention, it is configured as described above. A heat transfer path having a small thermal resistance is formed from the outside to the thermistor element. Therefore, heat conduction from the outside to the thermistor element can be improved. Accordingly, it is possible to provide a piezoelectric vibration element mounting substrate that can reduce the difference between the temperature of the external environment and the temperature information sensed by the thermistor element and can obtain good temperature characteristics.

  The piezoelectric device according to one aspect of the present invention includes the piezoelectric vibration element mounting substrate configured as described above, the piezoelectric vibration element mounted on the mounting portion, and the thermistor element housed in the through portion. Therefore, it is possible to reduce the difference between the temperature of the external environment and the temperature information sensed by the thermistor element, and to realize a piezoelectric device that can obtain good temperature characteristics.

  Moreover, since the thermistor element is accommodated in the penetration part provided in the bottom face part (1st base part) of the mounting part in which a piezoelectric vibration element is accommodated, it is advantageous also to thickness reduction.

(A) is a top view showing a piezoelectric vibration element mounting substrate and a piezoelectric device according to an embodiment of the present invention, (b) is a sectional view taken along line XX ′ of (a), and (c) is a bottom view. is there. It is sectional drawing in the Y-Y 'line | wire of Fig.1 (a).

(A) is a top view which shows the 1st modification of the board | substrate for piezoelectric vibration element mounting shown in FIG. 1, and a piezoelectric device, (b) is sectional drawing in the Y-Y 'line | wire. FIG. 6 is a top view showing a second modification of the piezoelectric vibration element mounting substrate and the piezoelectric device shown in FIG. 1. FIG. 10 is a top view illustrating a third modification of the piezoelectric vibration element mounting substrate and the piezoelectric device illustrated in FIG. 1. (A) And (b) is a top view which shows the other modification of the board | substrate for piezoelectric vibration element mounting shown in FIG. 1, and a piezoelectric device, respectively.

  A piezoelectric vibration element mounting substrate and a piezoelectric device according to the present invention will be described with reference to the accompanying drawings. FIG. 1A is a top view illustrating a piezoelectric vibration element mounting substrate and a piezoelectric device according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line XX ′ in FIG. FIG. 1C is a bottom view. FIG. 2 is a sectional view taken along line Y-Y ′ of FIG. 3A is a top view showing a first modification of the piezoelectric vibration element mounting substrate shown in FIG. 1, and FIG. 3B is a cross-sectional view taken along line YY ′ of FIG. It is sectional drawing. 4 and 5 are top views showing second to third modified examples of the piezoelectric vibration element mounting substrate shown in FIG. 1, respectively. In order to make it easy to see, piezoelectric vibration elements and the like are omitted in FIGS. 2 and 3B.

The piezoelectric vibration element mounting substrate of the present embodiment includes an insulating base 101, and the insulating base 101 (first base described later) has a mounting portion on the upper surface and a penetrating portion 103 penetrating from the upper surface to the lower surface. Have. Further, a frame-like metallized layer 104 surrounding the mounting portion 102 in plan view is provided. The piezoelectric vibration element 105 and the thermistor element 106 are mounted on the piezoelectric vibration element mounting substrate. Further, the mounting portion 102 is provided with a connection conductor 107, and a side conductor 108 is provided on the inner surface of the through portion 103.
Is provided. The piezoelectric vibration element 105 is connected to the connection conductor 107 via the first bonding material 109. The thermistor element 106 is connected to the side conductor 108 via the second bonding material 110. The mounting portion 102 is sealed with a metal cap 111, and the metal cap 111 is joined to the frame-like metallized layer 104 via a sealing material 112. An external connection conductor 113 for external connection is provided on the lower surface of the insulating base 101 (second base described later), and a through conductor 114 is provided on the second base. The insulating base 101 includes a first base 115 and a second base 116 below the first base 115. In this example, the insulating base 101 is further provided with a horizontal conductor 117. In each figure, the piezoelectric vibration element 105, the metal cap 111, and the like are shown by broken lines for easy identification.

  In the following description, the piezoelectric device of the embodiment in which the piezoelectric resonator element 105 and the thermistor element 106 are mounted (mounted) on the piezoelectric resonator element mounting substrate of the embodiment will be mainly described as an example. .

A piezoelectric vibration element mounting substrate is basically formed by the insulating base 101, the connection conductor 107, the side conductor 108 and the through conductor 114. A piezoelectric device is basically formed by mounting (mounting) the piezoelectric vibration element 105 and the thermistor element 106 on the piezoelectric vibration element mounting substrate.

The insulating base 101 has a flat plate shape as shown in FIG. In the piezoelectric device, a thermistor element 106 is accommodated in a through-hole 103 of a first base, which will be described later, of the insulating base 101. Further, the thermistor element 106 is electrically connected by a second bonding material 110 to a pair of side conductors 108 formed on the opposing inner side surfaces of the penetrating portion 103. Further, the piezoelectric vibration element 105 is mounted on the pair of connection conductors 107 formed on the mounting portion 102 by being electrically connected by the first bonding material 109.

The thermistor element 106 has a rectangular parallelepiped element body (no symbol) and electrodes as external connection terminals (no symbol) provided on the end face of the element body. The mounting portion 102 and the through portion 103 are sealed with a metal cap 111 joined to a frame-like metallized layer 104 surrounding the mounting portion 102 and the through portion 103. The thermistor element 106 and the piezoelectric vibration element 105 are hermetically sealed in the upper surface including the mounting portion 102 of the insulating base 101 and the inside of the container (not shown) between the through-hole 103 and the concave metal cap 111. . The metal cap 111 that seals the mounting portion 102 and the penetrating portion 103 is omitted in the top view such as FIG.

The insulating base 101 has a flat plate-like first surface having a mounting portion 102 on the upper surface thereof on a flat plate-like second base 116.
The base 115 is formed by being laminated. The through portion 103 formed in the first base 115 is a portion for accommodating the thermistor element 106 as described above. A second base 116 is formed at the bottom of the through portion 103.
The top surface of is exposed. For example, the thermistor element 106 is placed on the exposed upper surface.
A pair of side conductors 108 are formed on the inner side surface of the through-hole 103 so as to sandwich the thermistor element 106. The side conductor 103 in the example of FIG. 1 is, for example, a semicircular shape in a plan view provided in a groove provided on the inner surface of the through portion 103, but is provided in a layered manner on the inner side surface not including such a groove. It may be a

The first base 115 and the second base 116 forming the insulating base 101 are made of a ceramic material such as an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, or a glass-ceramic sintered body. Become. In addition, the insulating base 101 has, for example, a rectangular shape with a side length of about 1.6 to 5.0 mm in a plan view and a thickness of about 0.15 to 0.8 mm in plan view. The mounting portion 102 is provided. Further, the first base 115 has a penetrating portion 103 penetrating from the upper surface to the lower surface. As described above, the penetrating portion 103 is blocked by the upper surface of the second base portion 116, and the upper surface of the second base portion 116 is exposed therein. A recess (no symbol) is formed between the penetrating portion 103 and the upper surface of the second base portion 116, and the thermistor element 106 is accommodated in the recess.

Of the piezoelectric vibration element mounting substrate, a conductor portion other than the insulating base 101, that is, a conductor portion including the frame-shaped metallized layer 104, the connection conductor 107, the side conductor 108, the through conductor 114, and the horizontal conductor 117 is, for example, tungsten, It consists of metal materials, such as molybdenum, manganese, copper, silver, palladium, gold | metal | money, platinum, or the alloy material containing these metal materials. These conductor portions may be made of the same type of metal material, or may be made of different metal materials.

If the insulating base 101 (the first base 115 and the second base 116) is made of, for example, an aluminum oxide sintered body, an organic binder suitable for raw material powders such as aluminum oxide, silicon oxide, magnesium oxide, and calcium oxide. In addition, the mixture is mixed with a solvent, a plasticizer, etc. to make a mud, and this is formed into a sheet by a sheet forming method such as a doctor blade method or a roll calender method to obtain a plurality of ceramic green sheets. Are laminated, and the laminated body is integrally fired.

Further, the conductor portion of the frame-like metallized layer 104 or the like is formed by applying a paste of a metal material such as tungsten (metal paste) to a predetermined portion of a ceramic green sheet to be the insulating base 101 and firing it simultaneously. be able to. The metal paste is applied by a method such as a screen printing method.

In this case, some ceramic green sheets are appropriately punched to form through holes. Thereafter, the ceramic green sheet provided with the through hole is laminated on the ceramic green sheet not provided with the through hole and fired. As described above, the insulating base 101 having the penetrating portion 103 can be manufactured.

  Further, the side conductor 108 on the inner side surface of the penetrating portion 103 is formed as follows, for example. That is, before forming the through portion 103 as described above, a pair of holes are provided so as to straddle the outer periphery of the through portion 103, and tungsten, molybdenum, manganese, copper, silver, for example, are provided in the pair of holes. A metal paste of a metal material such as is filled. Thereafter, the ceramic green sheet is appropriately punched to form the penetrating portion 103. Thereby, a pair of side conductors 108 exposed on the inner side surface of the through portion 103 can be formed.

  The insulating base 101 is manufactured as a so-called multi-piece wiring board (not shown) in which a plurality of wiring board regions (not shown), each of which becomes such an insulating base 101, are arranged vertically and horizontally on a ceramic mother board. However, it may be manufactured by a method of cutting it at the boundary of the wiring board region and dividing it into pieces.

In this embodiment, a frame-like metallized layer 104 is formed on the outer periphery of the upper surface of the insulating substrate 101. The frame-like metallized layer 104 surrounds the mounting portion 102 and the through portion 103 in plan view. In the piezoelectric device, a metal cap 111 is joined to the frame-like metallized layer 104. The frame-like metallized layer 104 is for joining the metal cap 111 to the insulating base 101 by means such as brazing. When means other than brazing, for example, a lid made of resin or the like (not shown) is bonded to the insulating base 101 with an adhesive, the frame-like metallized layer 104 may not be provided.

Further, the frame-like metallized layer 104 may be electrically connected to an external ground potential, for example. In this case, the frame-like metallized layer 104 and the metal cap 111 improve the electromagnetic shielding effect on the inside of the container. The electrical connection between the frame-like metallized layer 104 and the metal cap 111 can be performed by means such as brazing them together as described above or bonding them with a conductive adhesive.

As described above, the frame-like metallized layer 104 is formed of a metal material such as tungsten, molybdenum, manganese, copper, or silver. The frame-like metallized layer 104 can be formed, for example, by printing a metal paste such as tungsten in a predetermined pattern on the outer periphery of the upper surface of the ceramic green sheet to be the insulating base 101 (first base 115) and co-firing. it can. This firing is performed, for example, after a ceramic green sheet printed with a metal paste that becomes the frame-like metallized layer 104 is laminated on a ceramic green sheet that becomes the second base 116 to form a laminate.

The frame-like metallized layer 104 includes a nickel plating layer (not shown) having a thickness of about 1 to 20 μm and a thickness of about 0.1 to 2 μm on the exposed surface in order to prevent oxidative corrosion and improve the bonding strength of the brazing material. The gold plating layers (not shown) are preferably sequentially deposited.

The metal cap 111 is made of a metal material such as an iron-nickel alloy or an iron-nickel-cobalt alloy, and is joined to the insulating base 101 with a metal brazing material, a resin, or the like. As described above, the metal cap 111 functions as a metal member constituting the container.

For example, the metal cap 111 has a rectangular plate shape with a thickness of about 0.1 to 0.5 mm and a width of about 0.15 to 0.5 mm joined to the frame-like metallized layer 104, for example. Examples of the method for brazing the metal cap 111 to the frame-like metallized layer 104 include the following methods. First, a sealing material 112 such as a gold-tin alloy or a gold germanium alloy having a thickness of 20 to 50 μm is previously applied to the lower surface of the metal cap 111, and the lower surface to which the sealing material 112 is applied is framed. It is placed on the metallized layer 104 (specifically, a gold plating layer deposited on the frame-like metallized layer 104). Then, the method of heating with an electric furnace etc. can be mentioned, temporarily fixing these with a jig | tool etc. By this method, the metal cap 111 can be easily bonded to the frame-like metallized layer 104. The sealing material 112 may be a resin depending on the sealing environment of the mounting unit 102.

The sealing material 112 such as a gold-tin alloy is, for example, a gold-tin eutectic alloy based on a gold-tin eutectic composition and has a melting point of about 270 to 300 ° C. By using such a sealing material 112, the metal cap 111 can be brazed to the frame-like metallized layer 104 in a heat treatment (in an inert gas or vacuum environment) at about 300 ° C. As a result, the frame-like metallized layer 104 and the metal cap 111 are firmly joined. Therefore, the container is hermetically sealed, and the piezoelectric vibration element 105 mounted on the mounting portion 102 can operate normally and stably over a long period of time.

A thermistor element 106 is accommodated in the through portion 103 of the insulating base 101. As described above, the thermistor element 106 has a pair of electrodes (not indicated) for external connection on at least the lower surface at both ends of the element body. These electrodes are electrically and mechanically connected to a pair of side conductors 108 provided on the inner side surface of the through portion 103.

The electrodes of the thermistor element 106 connected to the pair of side conductors 108 are connected to the lower surface side of the insulating base (second base 116) by a pair of through conductors 114 provided from the lower end of the side conductor 108 to the lower surface of the second base 116. Is electrically derived. For example, the external connection conductor 113 may be disposed in the lead-out portion. The external connection conductor 113 is connected to the external electric circuit via a conductive connection material such as solder or a conductive adhesive.

The thermistor element 106 is for performing temperature compensation for the piezoelectric vibration element 105. In the piezoelectric device of the embodiment, a piezoelectric device capable of detecting a temperature change at a position closer to the piezoelectric vibration element 105 is realized.

As described above, the thermistor element 106 functions to sense the temperature of the piezoelectric vibration element 105 and transmit it to an external temperature compensation circuit. Therefore, the thermistor element 106 is electrically connected to an external electric circuit (not shown) having functions such as temperature compensation. Therefore, the thermistor element 106 and the piezoelectric vibration element 105 are not electrically connected inside and outside the insulating base 101. Electrical connection between the thermistor element 106 and the external electric circuit is made through the side conductor 108 and the through conductor 114. In other words, a continuous conductor (metal) portion including the side conductor 108 and the through conductor 114 is provided from the electrode portion of the thermistor element 106 to the lower surface of the insulating base 101 (second base 116).

The through conductor 114 and the external connection conductor 113 can also be formed by applying a metal paste such as tungsten to a predetermined portion of the ceramic green sheet serving as the insulating base 101 and simultaneously firing the metal paste as described above. In this case, the metal paste that becomes the through conductor 114 is, for example,
It fills in the through-hole previously formed in the ceramic green sheet by mechanical processing.

Because of such a structure, for example, the side conductor 108 and the through conductor 114, which are made of a metal material having a relatively large thermal conductivity and have a relatively large cross-sectional area, have a low thermal resistance from the outside to the thermistor element 106. A heat path is formed. Therefore, heat conduction from the outside to the thermistor element 106 can be improved. Accordingly, it is possible to provide a piezoelectric vibration element mounting substrate and a piezoelectric device that can reduce the difference between the temperature of the external environment and the temperature information sensed by the thermistor element 106 and can obtain good temperature characteristics.

  Further, in the piezoelectric device according to the embodiment, a part of the container is constituted by a metal cap 111 that is excellent in heat conduction as compared with, for example, a ceramic material. In such a case, the temperature change of the external environment can be more effectively conducted to the insulating base 101. That is, it is an advantageous form for performing temperature compensation with higher accuracy.

The thermistor element 106 is connected to the side conductor 108 by a second bonding material 110. In this case, a bonding material or the like (not shown) for bonding and fixing the thermistor element 106 to the insulating base 101 between the thermistor element 106 and the upper surface of the second base 116 (the exposed surface at the bottom of the through portion 103). There is no intervening. Therefore, it is advantageous in reducing the thickness after mounting the thermistor element 106, and is advantageous in further reducing the height of the piezoelectric device.

In the chip-like thermistor element 106, for example, electrodes for external connection are formed at both ends of a thermistor element body (element body) (not indicated). If the thermistor element is an NTC (negative temperature coefficient) type, the main body is made of a thermistor material such as a Mn—Co—Cu-based material or a Mn—Co—Fe-based material. If the thermistor element is a PTC (positive temperature coefficient) type, the main body is formed of a thermistor material such as a Ba-Ti-O-based material.

If the thermistor element 106 is a stacked thermistor element, each of the internal electrodes (
A plurality of layers having (not shown) are stacked. Due to this structure, the resistance can be reduced as compared with a chip-type thermistor element having no internal electrode inside the element body. That is, it has a plurality of internal electrodes formed inside the ceramic body and external connection terminals connected to one end of the internal electrode and formed at both ends of the ceramic body. That is, since the ceramic body is formed by alternately laminating a plurality of ceramic layers and internal electrode layers, the resistance can be reduced. Therefore, high accuracy of the resistance value with respect to the temperature change can be obtained, so that power consumption as the device can be suppressed.

Further, the piezoelectric vibration element mounting substrate and the piezoelectric device of the example shown in FIG. 3 have the frame-shaped metallized layer 104, and one of the pair of side conductors 108 is connected to the frame-shaped metallized layer 104 as a ground potential. Electrically connected. In this case, the shielding property against electromagnetic waves from outside (electromagnetic shielding property) is improved, and the temperature information of the thermistor element (thermistor element 106).
It is possible to reduce the noise from entering the value obtained as a voltage by converting the resistance value output from.

  That is, the upper surface of the piezoelectric device in which the metal cap 111 is further bonded to the frame-shaped metallized layer 104 is covered with the metal cap 111 and the frame-shaped metallized layer 104. In addition, a part of the thermistor element 106 is covered on the lower surface thereof by the external connection conductor 113 that becomes the ground potential of the thermistor element 106. Therefore, the thermistor element 106 is more effectively protected from external noise. Therefore, noise is reduced in the temperature information of the thermistor element 106 as compared with the conventional piezoelectric device, and a more accurate value (temperature information) of the thermistor element 106 can be output. Then, the difference between the temperature information obtained in this way and the actual temperature around the piezoelectric vibration element 105 is reduced.

In this case, the metal cap 111 whose outer surface is exposed to the external environment is also thermally connected to one of the side conductors 108 via the frame-like metallized layer 104. Therefore, it is possible to obtain an effect that the temperature of the external environment is transmitted more effectively by the thermistor element 106.

For example, in the case of a piezoelectric device (not shown) including an insulating base having a recess on the upper surface, for example, a lid made of metal or the like is bonded on the upper surface, but the frame surrounding the recess is insulated on the side of the insulating base. Since the body is made of a ceramic material, it is difficult to cover the thermistor element 106 with a member having a ground potential. However, according to the piezoelectric device of this embodiment, the insulating base 101 has a flat plate shape, and the thermistor element 106 can be covered with the metal cap 111 connected to the ground potential on the upper surface of the piezoelectric device.

Further, according to the piezoelectric device of this embodiment, one of the external connection terminals (electrodes) formed at both ends of the thermistor element 106 is electrically connected to the metal cap 111 that becomes the ground potential. Therefore, even if another electronic component (not shown) having a different potential is mounted in the vicinity of the piezoelectric device on the external substrate on which the piezoelectric device is mounted, the excitation electrode of the piezoelectric vibration element 105 is mounted. Since it is difficult for stray capacitance to occur between (not shown) and other electronic components, fluctuations in the oscillation frequency can be reduced.

As shown in FIG. 3, for example, the horizontal conductor 117 may be used to electrically connect the side conductor 108 and the frame-like metallized layer 104 that are at the ground potential. The horizontal conductor 117 can also be formed by the same method using the same metal material as the frame-shaped metallized layer 104. Here, since the metal cap 111 is connected to the frame-like metallized layer 104 by a sealing material 112 such as a gold-tin alloy,
There is a possibility that a part of the sealing material 112 flows into the horizontal conductor 117 and the volume of the sealing material 112 is partially reduced. Therefore, for example, a ceramic coat (not shown) may be formed so as to straddle the sealing material 112 to act as a dam for preventing the sealing material 112 from flowing out.

  Further, a horizontal conductor 117 is formed between the first base 115 and the second base 116 so that the horizontal conductor 117 contacts the lower surface of the side conductor 108 and other through conductors connected to the frame-like metallized layer 104. It may be. When the horizontal conductor 117 is formed inside the insulating base 101, the flow of the sealing material 112 along the horizontal conductor is suppressed.

In the example of the piezoelectric device as shown in FIG. 4, the lower ends of the pair of through conductors 114 are directly connected to the upper ends of the external connection conductors 113 formed on the lower surface of the second base portion 116. In such a structure, the thermistor element 106 and the external connection conductor 113 can be connected by a through conductor 114 having a relatively large cross-sectional area without passing through a horizontal conductor (not shown in FIG. 4). That is, the cross-sectional area of the through conductor 114 serving as a heat conduction path between the thermistor element 106 and the external connection conductor 113 is large, and the length of the path can be shortened. Therefore, the temperature difference between the external environment and the thermistor element 106 can be effectively reduced. Therefore, it is possible to provide a piezoelectric vibration element mounting substrate and a piezoelectric device that can obtain even better temperature characteristics.

In order to directly connect the lower ends of the pair of through conductors 114 to the upper ends of the external connection conductors 113, for example, the short side of the rectangular through part 103 in a plan view of the lower surface of the insulating base 101 (base 115). It suffices that at least a part of the external connection conductor 113 is positioned immediately below the end of the external connection conductor 113. The lower ends of the through conductors 114 directly connected to the inner side surface conductor 108 on the short side of the through portion 103 are directly connected to the upper ends of the external connection conductors 113, respectively.

In this case as well, one of the pair of side conductors 108 may be electrically connected to the frame-like metallized layer 104. The side conductor 108 (one) electrically connected to the frame-like metallized layer 104 is, for example, a ground potential. The electrical connection to the frame-like metallized layer 104 further stabilizes the ground potential. Is possible.

In this case, the frame-shaped metallization layer is formed so that the upper surface of the side conductor 108 is flush with the upper surface of the first base 115 and further surrounds the mounting portion 102 and covers a part of the side conductor 108. 104 is formed. The upper surface of the side conductor 108 is the same height as the upper surface of the first base 115, and the flatness of the frame-like metallized layer 104 is ensured. Therefore, since it is difficult for a gap to be formed between the metal cap 111 and the frame-like metallized layer 104, the metal cap 111 and the frame-like metallized layer 104 can be well bonded and sealed with a small amount of the sealing material 112. It becomes possible.

In addition, as shown in FIG.
It may be biased to the side (direction toward the side of the insulating substrate 101). In this case, the external connection terminal of the thermistor element 106 is connected to the side conductor 108 in the through portion 103 by the second bonding material 110. Therefore, the area of the overlapping region between the side conductor 108 and the frame-like metallized layer 104 in a plan view becomes larger, and the electrical connection with the metal cap 111 that becomes the ground potential can be performed satisfactorily. In addition, the apparent area of the side conductor 108 formed on the upper surface of the first base 115 can be made smaller (a part of the side conductor 108 is covered with the frame-like metallized layer 104). In other words, the proportion of the side conductors 108 in the piezoelectric vibration element mounting substrate and the piezoelectric device in plan view is smaller. Therefore, it is advantageous for downsizing. Further, the flow of the sealing material 112 is more effectively suppressed. Since a dam portion (not shown) such as a ceramic coat for preventing the flow out is unnecessary, it is further advantageous in terms of downsizing and productivity.

The lower end of the side conductor 108 is directly connected to the upper end of the through conductor 114 without passing through a horizontal conductor (not shown in FIG. 4), and the lower end of the through conductor 114 is formed on the lower surface of the second base 116. The external connection conductor 113 is directly connected. Since the heat conduction path can be shortened without passing through the horizontal conductor, the temperature difference between the temperature of the external environment and the thermistor element 106 is further effectively reduced.

Further, the through portion 103 may be provided obliquely at a position other than the connection conductor 107 on the upper surface of the first base 115 in plan view. The penetration part 103 is provided obliquely. For example, the upper surface of the first base part 115 and the penetration part 103 which are both rectangular in a plan view are arranged so that their longitudinal directions are oblique to each other (not parallel). ) Means being placed. It can also be considered that the penetrating portion 103 is inclined with respect to the outer side of the insulating base 101.

When the penetrating part 103 is provided obliquely, the penetrating part 103 is arranged such that its longitudinal direction is along the diagonal line of the upper surface of the first base 115, for example. In this case, when the two external connection conductors 113 connected to the thermistor element 106 are arranged on the lower surface of the insulating base 101 on the diagonal line (two opposite corners), the side conductors 108 and Electrical connection with the external connection conductor 113 is easier.

That is, for example, as shown in FIG. 5, since the through portion 103 is provided obliquely, the position of the inner side surface of the through portion 115, that is, the position of the side conductor 108 is outside the diagonal line on the lower surface of the insulating base 101. The positions of the connecting conductors 113 are likely to overlap with each other in plan perspective. Therefore, the pair of side conductors 108 and the pair of through conductors 114 to which the thermistor element 106 is connected are directly connected to the two external connection conductors 113 disposed on the diagonal line on the lower surface of the insulating base 101 without using a horizontal conductor. It becomes easier to connect to.

The example shown in FIG. 5 will be described in more detail as follows. That is, the penetration part 103
Is provided obliquely with respect to the outer side of the insulating base 101, and the pair of side conductors 108 and the pair of through conductors 114 are formed on the lower surface of the insulating base 101 and are arranged on the diagonal line of the external connection conductor 113. The two are connected separately without using a horizontal conductor. Further, the pair of connection conductors 107 to which the piezoelectric vibration element 105 is connected are formed on the lower surface of the insulating base 101 and are separately connected to two other external connection conductors 113 arranged on a diagonal line. Here, one of the connection conductors 107 is connected to the mounting portion 102 via a horizontal conductor (not shown) and a through conductor, for example, as shown in FIG. 5, in order to connect to another external connection conductor 113. Has been.

Since the thermistor element 106 has a smaller area and a larger thickness than the piezoelectric vibration element 105, the piezoelectric vibration element 105 is disposed so as to cover the thermistor element 106 accommodated in the through portion 103.

As described above, the piezoelectric device of this embodiment is accommodated in the piezoelectric vibration element mounting substrate of the form shown in FIG. 1, the piezoelectric vibration element 105 mounted on the mounting portion 102, and the through-hole 103, for example. The thermistor element 106 is included. With such a structure, a thin piezoelectric device that can reduce the difference between the temperature of the external environment and the temperature of the thermistor element and obtain good temperature characteristics can be realized.

That is, a heat transfer path having a low thermal resistance is formed from the outside to the thermistor element 106 by the side conductor 108 and the through conductor 114 made of a metal material having a relatively large thermal conductivity and having a relatively large cross-sectional area of the conductor. Therefore, heat conduction from the outside to the thermistor element 106 can be improved. Therefore, it is possible to provide a piezoelectric device that can reduce the difference between the temperature of the external environment and the temperature of the thermistor element 106 and obtain good temperature characteristics.

Further, when a container as a piezoelectric device is constituted by the flat insulating base 101 and the concave metal cap 111, for example, a frame-like metal member or ceramic member (so-called frame portion) is formed on the upper surface of the insulating base 101. Compared to a structure provided with (not shown), there is also an effect that the structure becomes simpler. Then, the size of the metal cap 111 is appropriately selected according to the size of the piezoelectric vibration element 105, and the area and depth of the penetrating portion 103 that is the first base 115 are determined according to the size and thickness of the thermistor element 106. It is sufficient to select an appropriate size. Therefore, since it is not necessary to newly recreate a jig such as a ceramic green sheet punching die by changing the accommodation width as a container as in the prior art, the manufacturing cost can be reduced.

Furthermore, since the side surface (frame part) of the container is not a ceramic material, it is possible to suppress a decrease in the reliability of hermetic sealing due to mechanical breakage of the frame part. The mechanical destruction of the frame portion is caused by, for example, thermal stress when a mounting portion 102 is sealed by joining a flat lid (not shown) made of metal or the like onto the frame portion by seam welding or the like. . On the other hand, if the metal cap 111 is configured as described above, the frame portion is not damaged. Therefore, a piezoelectric device that is more advantageous in terms of improving the reliability of hermetic sealing can be provided. Further, since the frame portion is unnecessary, it is advantageous in terms of thinning. In addition, as described above, it is advantageous for improving electromagnetic shielding between the inside and outside of the container.

Here, for joining the frame-like metallized layer 104 and the metal cap 111, for example, a sealing material 112 such as a gold-tin alloy or a gold germanium alloy can be used. The melting point of the gold-tin alloy is about 270 to 300 ° C, and the melting point of the gold-germanium alloy is about 340 to 370 ° C. By using the bonding material 112 made of these metals, it is possible to realize a piezoelectric device having an internal environment with a relatively high degree of vacuum with less generation of gas during sealing.

  In recent years, a piezoelectric device using a resin as the bonding material 112 has been proposed as a method for sealing the mounting portion 102. Resin may be used as the sealing material 112 in consideration of the sealing environment according to the characteristics of the piezoelectric vibration element 105 mounted on the mounting portion 102. If a resin is used as the sealing material 112, an expensive metal brazing material is not used, so that a piezoelectric device that is less expensive than the conventional one can be realized.

Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, in FIGS. 1 to 5, the container is formed by the flat insulating base 101 and the metal cap 111, but a metal frame (not shown) is brazed to the frame-like metallized layer 104 of the flat insulating base 101. It is also possible to have a structure in which the mounting portion 102 is covered with a metal member in the same manner as the metal cap 111 by bonding with a material or the like and bonding a metal lid (not shown) on the metal frame. Since metal members such as a metal frame and a metal lid are excellent in heat conduction, even such a structure has the same effect as the metal cap 111 that is excellent in heat conduction compared to a ceramic material. Since it is easy to conduct the temperature change of the external environment more effectively, it is advantageous in performing temperature compensation with higher accuracy.

For example, as shown in FIGS. 6A and 6B, the side conductors 108 and the through conductors 114 are set in various shapes and arrangement positions as long as they satisfy the condition that they are in direct contact with each other. Can be done. In the example of FIG. 6A, the size or arrangement position of the through conductor 114 in plan view is different from the example of FIG. The penetrating conductor 114 is appropriately selected depending on the heat transferability, the mechanical strength of the insulating base 101, the arrangement space of other conductors (not shown) provided on the insulating base 101, and the like.
The size or arrangement position may be set. In the example on the upper side of FIG. 6A, the position of the through conductor 114 is biased inward with respect to the side conductor 108, and for example, the mechanical strength in the outer peripheral portion of the insulating base 101 is improved. In the example on the lower side of FIG. 6B, the relatively large through conductor 114 is in contact with the entire lower surface of the side conductor 108, and for example, heat conductivity is enhanced.

In the example of FIG. 6B, the number, size, or arrangement position of the side conductors 108 in a plan view is as shown in FIG.
Different from the example. The number, size, arrangement position, and the like of the side edge conductors 108 may be appropriately set according to the convenience of heat transfer and the strength of bonding between the insulating base 101 and the side conductors 108. In the example on the upper side of FIG. 6B, two arc-shaped side conductors 108 are provided, so that more effective suppression of heat transfer bias is achieved. Also in the example on the lower side of FIG. 6B, three side conductors 108 are provided to suppress the unevenness of heat transfer. As in this example, the side conductor 108 may have an elliptical arc shape in plan view, and the plurality of side surface conductors 108 may include an elliptical arc shape.

  However, considering the efficiency of heat transfer (particularly, the ratio of the volume contributing to heat transfer with respect to the surface area of the side conductors), ease of design, productivity, economy, etc., for example, examples of FIGS. As described above, it is preferable that the circular through conductor 114 is provided in contact with the lower side of the side conductor 108 provided in the groove of the inner surface of the through portion 103.

  The side conductors 108 and the through conductors 114 may be mixed in different forms in one insulating base 101 as in the example of FIG.

101 ... Insulating substrate
102 ・ ・ ・ Mounting part
103 ... penetration part
104 ... Frame metallization layer
105 ・ ・ ・ Piezoelectric vibration element
106 ・ ・ ・ Thermistor element
107 ・ ・ ・ Connection conductor
108 ・ ・ ・ Side conductor
109 ... 1st bonding material (piezoelectric vibration element)
110 ・ ・ ・ Second bonding material (Thermistor element)
111 ・ ・ ・ Metal cap
112 ・ ・ ・ Encapsulant
113 ・ ・ ・ External connection conductor
114 ... Penetration conductor
115 ... 1st base
116 ... 2nd base
117 ・ ・ ・ Horizontal conductor

Claims (5)

A first base having a top surface including a mounting portion of the piezoelectric vibration element and a bottom surface opposite to the top surface, having a penetrating portion penetrating from the top surface to the bottom surface and accommodating a thermistor element; An insulating base having a second base disposed on the lower surface of the first base so as to close the lower end of the penetrating part;
A pair of connecting conductors provided in the mounting portion;
A pair of side conductors provided on the inner side surface of the penetrating portion;
A piezoelectric vibration element mounting substrate comprising: a pair of through conductors provided from a lower end of the pair of side conductors to a lower surface of the second base portion. A frame-like metallization layer formed on the upper surface of the first base portion so as to surround the mounting portion in plan view;
2. The piezoelectric vibration element mounting substrate according to claim 1, wherein one of the pair of side conductors is electrically connected to the frame-shaped metallized layer. The external connection conductor provided in the lower surface of the said 2nd base is further provided, The lower end of a pair of said penetration conductor is directly connected with the said external connection conductor, The Claim 1 or Claim 2 characterized by the above-mentioned. The piezoelectric vibration element mounting substrate described in 1. 2. The piezoelectric vibration element mounting substrate according to claim 1, wherein the through portion is obliquely provided at a position other than the first connection conductor on the upper surface of the first base portion in a plan view. A piezoelectric device comprising: the piezoelectric vibration element mounting substrate according to claim 1; a piezoelectric vibration element mounted on the mounting portion; and a thermistor element housed in the through portion.

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