JP2014143487A - Packaging structure and piezoelectric device - Google Patents

Abstract

A mounting structure and a piezoelectric device that can realize further downsizing of a mounting structure that accommodates a piezoelectric vibration element and a thermistor element.
An element mounting including an insulating substrate, the insulating substrate having an upper surface including a first mounting portion on which a piezoelectric vibrating element is mounted and a lower surface including a second mounting portion. And a thermistor element 112 provided on the second mounting portion, and the element mounting container further includes a first external connection terminal 114 provided on the lower surface of the insulating base. The thermistor element includes an element main body bonded to the insulating base and a second external connection terminal 115 provided on the lower surface of the element main body.
[Selection] Figure 1

Description

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

  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.

  In recent years, a piezoelectric device in which a thermistor element is mounted in the vicinity of the piezoelectric vibration element has been proposed for more accurate temperature compensation of the piezoelectric vibration element accommodated in the mounting portion. This makes it possible to detect a temperature change at a position closer to the piezoelectric vibration element, and improves the accuracy of temperature compensation.

  The piezoelectric vibration element mounting substrate used in such a piezoelectric device includes, for example, an insulating base having concave mounting portions on the upper surface and the lower surface. A piezoelectric vibration element is mounted on the upper mounting portion, and a thermistor element is mounted on the lower mounting portion. The piezoelectric vibration element is mounted on a mounting structure in which the thermistor element is mounted on the piezoelectric vibration element mounting substrate. Since the piezoelectric vibration element and the thermistor element are mounted on the same insulating substrate, a piezoelectric device in which both positions are close to each other can be manufactured.

  In the piezoelectric vibration element mounting substrate (mounting structure) 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. Provided (see Document 1).

JP 2008-263564 A

  In recent years, in the piezoelectric vibration element mounting substrate (mounting structure) and the piezoelectric device of the prior art described above, for example, for further miniaturization and higher functionality of equipment on which the piezoelectric device is mounted, further space saving is achieved. (Miniaturization in plan view) has been demanded.

  Specifically, when the piezoelectric vibration element mounting substrate (mounting structure) is further reduced in size, it has become difficult to provide external connection terminals with sufficient dimensions on the lower surface of the insulating base.

  A mounting structure according to an aspect of the present invention includes an insulating base, and the insulating base includes an upper surface including a first mounting portion on which a piezoelectric vibration element is mounted and a lower surface including a second mounting portion. An element mounting container and a thermistor element provided in the second mounting portion, and the element mounting container further includes a first external connection terminal provided on the lower surface of the insulating base. The thermistor element includes an element body bonded to the insulating base and a second external connection terminal provided on the lower surface of the element body.

  A piezoelectric device according to one aspect of the present invention includes the mounting structure described above and a piezoelectric vibration element mounted on the first mounting portion and electrically connected to the first external connection terminal. It is characterized by providing.

  According to the mounting structure of one aspect of the present invention, since the electrode of the thermistor element is used as it is as the first external connection terminal as it is, the external connection terminal for the thermistor element is separately provided on the insulating base. There is no need to provide it on the lower surface. Therefore, it is possible to provide a mounting structure capable of further space saving. In addition, it is easy to reduce the conduction resistance between the thermistor element and the external electric circuit, which is effective in improving the accuracy of temperature compensation.

  According to the piezoelectric device of one aspect of the present invention, the mounting structure having the above-described configuration, the piezoelectric vibration element mounted on the first mounting portion and electrically connected to the first external connection terminal, Therefore, a piezoelectric device capable of further space saving can be provided. In addition, since the electrodes of the thermistor element can be directly joined to an external electric circuit such as a circuit board, a piezoelectric device having excellent temperature compensation accuracy can be provided.

(A) is a top view showing a mounting structure and a piezoelectric device according to an embodiment of the present invention, (b) is a sectional view taken along line X-X ′ in (a), and (c) is a bottom view. It is a bottom view which shows the 1st modification of the mounting structure shown in FIG. 1, and a piezoelectric device. It is a bottom view which shows the 2nd modification of the mounting structure shown in FIG. 1, and a piezoelectric device. (A) And (b) is a bottom view which shows the 3rd and 4th modification of the mounting structure shown in FIG. 1, and a piezoelectric device, respectively.

  A mounting structure and a piezoelectric device according to the present invention will be described with reference to the accompanying drawings.

1A is a top view illustrating a mounting structure and a piezoelectric device according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line XX ′ of FIG. (C) is a bottom view. FIGS. 2 and 3 are bottom views of the first and second modifications of the mounting structure shown in FIG. 1, respectively. 1-3, 101 is an insulating substrate, 102 is a base, 103 is a frame, 104 is a leg, 105 is a first mounting part, 106 is a connection conductor, 107 is a piezoelectric vibration element, 108 is a bonding material, 109 Is a metal frame layer, 110 is a metal frame, 111 is a second mounting portion, 112 is a thermistor element, 113 is a fixing member, 114 is a first external connection terminal, 115 is a second external connection terminal, 116 is a lid, 117 is a notch.

  In this embodiment, the insulating base 101 is formed by a base 102, a frame 103, and a leg 104.

The insulating base 101 is provided with a frame-like metallized layer 109. A metal frame 110 is bonded to the frame-shaped metallized layer 109. The insulating base 101 has an upper surface including the first mounting portion 105 on which the piezoelectric vibration element 107 is mounted. An element mounting container (no symbol) is formed by an insulating base 101 having an upper surface including the first mounting portion 105 and a lower surface including the second mounting portion 111. A second external connection conductor 115 is disposed on the insulating base 101.

As shown in FIG. 1B, the insulating base 101 has an H-shaped cross section (vertical cross section) in the thickness direction. A piezoelectric vibration element 107 is hermetically sealed on the first mounting portion 105 of the insulating base 101.

The insulating base 101 has a lower surface including the second mounting portion 111. The thermistor element 112 is mechanically fixed to the second mounting portion 111 by a fixing member 113. A mounting structure is basically formed by the insulating base 101 and the thermistor element 112. The thermistor element 112 has a rectangular parallelepiped element body (no reference) and an electrode as a second external connection terminal 115 provided on the lower surface of the element body. Details of the thermistor element 112 and the second external connection terminal 115 will be described later.

The first mounting portion 105 is sealed with a lid body 116 joined to a portion of the insulating base 101 surrounding the first mounting portion 105. The piezoelectric vibration element 107 is hermetically sealed inside a container (not shown) constituted by the first mounting portion 105 and the lid body 116. A lid 116 for sealing the first mounting portion 105
Are omitted in FIG. 1 (a) for the sake of clarity.

As described above, the insulating base 101 has the frame portion 103 constituting the first mounting portion 105 laminated on the flat base portion 102. A pair of legs 104 are stacked below the flat base 102 so as to sandwich the thermistor element 112 mounted on the second mounting portion 111. A first mounting portion 105 for housing the piezoelectric vibration element 107 is formed by the inner side surface of the frame portion 103 and the upper surface of the base portion 102 exposed inside the inner side surface. A second mounting portion 111 on which the thermistor element 112 is mounted is formed on the lower surface of the base portion 102 between the pair of leg portions 104.

  The base part 102, the frame part 103, and the leg part 104 forming the insulating base 101 are made of, for example, an insulating layer (no reference) or a laminated body of a plurality of insulating layers. Each insulating layer is 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.

The insulating base 101 has, for example, a rectangular shape with a side length of about 1.6 to 7.0 mm and a thickness of about 0.25 to 1.5 mm in plan view, and has an upper surface and a lower surface as described above. First and second mounting portions 105 and 111 are provided.

Insulating base 101 (base portion 102, frame portion 103 and leg portion 104) is a raw material powder such as aluminum oxide, silicon oxide, magnesium oxide and calcium oxide if each insulating layer 111 is made of an aluminum oxide sintered body. Add a suitable organic binder, solvent, plasticizer, etc. to the mixture to make a mud, and make it into a sheet by a sheet forming method such as a doctor blade method or a roll calender method. Are obtained, and these are laminated, and the laminate is integrally fired.

In this case, an appropriate punching process is performed on a part of the ceramic green sheets to form a frame shape, and an appropriate punching process is applied to a part of the ceramic green sheets that form the legs 104 to form a long hole. In addition to forming, laminating so that a frame-shaped ceramic green sheet is positioned on the upper surface of the flat ceramic green sheet and a long-hole ceramic green sheet is positioned on the lower surface of the flat ceramic green sheet, respectively. By firing the laminated body at a high temperature, the insulating base 101 including the frame portion 103 and the leg portion 104 can be manufactured.

  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.

A frame-like metallized layer 109 is formed on the upper surface of the insulating base 101 (frame portion 103). The frame-like metallized layer 109 surrounds the first mounting part 105. A metal frame 110 is bonded to the frame-like metallized layer 109, and a lid 116 made of metal is brazed to the upper surface of the metal frame 110.
The frame-like metallized layer 109 is for joining the metal frame 110 to the insulating base 101 by means such as brazing.

The frame-like metallized layer 109 is made of a metal material such as tungsten, molybdenum, manganese, copper, or silver. The frame-like metallized layer 109 is formed by, for example, printing such a paste of a metal material such as tungsten (metal paste) in a predetermined pattern on the upper surface of the ceramic green sheet to be the frame part 103 and simultaneously firing it. Can do. For example, a frame-shaped ceramic green sheet printed with a metal paste that forms the frame-shaped metallized layer 109 is used for the firing, and other ceramic green sheets (a plate-shaped ceramic green sheet and a ceramic green that becomes the lower leg 104). Sheet).

The frame-like metallized layer 109 has a nickel plating layer (not shown) with a thickness of about 1 to 20 μm and a thickness of about 0.1 to 2 μm on the exposed surface to prevent oxidative corrosion and improve the bonding strength of the brazing material. The gold plating layers (not shown) are preferably sequentially deposited.

A metal frame 110 is bonded to the frame-shaped metallized layer 109. The metal frame 110 is made of, for example, a metal material such as iron-nickel alloy or iron-nickel-cobalt alloy, and functions as a metal member for joining the lid 116 to the insulating base 101 by a method such as seam welding. The metal frame 110 has, for example, a rectangular frame shape with a thickness of about 0.1 to 0.5 mm and a width of about 0.15 to 0.5 mm. As a method of brazing the metal frame 110 to the frame-like metallized layer 109, for example, a silver brazing (not shown) with a thickness of 20 to 50 μm is previously applied to the lower surface of the metal frame 110, The lower surface on which the silver solder is deposited is placed on a frame-like metallized layer 109 (specifically, a nickel plating layer deposited on the frame-like metallized layer 109), and these are temporarily fixed with a jig or the like The method of heating with an electric furnace etc. can be mentioned. By this method, the metal frame 110 made of metal can be easily brazed to the frame-like metallized layer 109 easily. Thereafter, a gold plating layer is applied to the metal frame 110 and other exposed metal layers.

The brazing material such as silver brazing is, for example, silver brazing based on a silver-copper eutectic composition (for example, 71 to 73 mass% silver-27 to 29 mass% copper, JIS name: BAg-8). In the case of BAg-8, the melting point is about 780 ° C. By using such a brazing material, the metal frame 110 can be brazed to the frame-like metallized layer 109 in a heat treatment (reducing atmosphere) of about 800 to 850 ° C. The brazing material may be added with a metal element such as tin or zinc in order to adjust wettability, melting temperature, etc. according to the size, shape, application, etc. of the insulating substrate 101.

The lid 116 is, for example, a square plate and is made of a metal material such as an iron-nickel alloy or an iron-nickel-cobalt alloy. The lid 116 is joined to the metal frame 110 by the brazing method or the welding method (for example, seam welding or electron beam welding). In order to join the lid 116 to the metal frame 110, a nickel plating layer is previously deposited on the main surface of the lid 116, and the nickel plating layer is melted by a welding method or the like to thereby form the metal frame 110. The lid body 116 is joined to the head.

Thereby, the metal frame 110 and the lid 116 are firmly joined. As described above, the metal frame is firmly bonded to the frame-like metallized layer 109 on the upper surface of the insulating base 101 (frame portion 103) by silver brazing or the like. Therefore, the hermetic sealing of the container is good, and the piezoelectric vibration element 107 accommodated in the first mounting part 105 can operate normally and stably over a long period of time.

A thermistor element 112 is mounted on the second mounting portion 111 on the lower surface of the insulating base 101. This thermistor element 112 is for realizing a piezoelectric device capable of detecting a temperature change at a position closer to the piezoelectric vibration element 107, and it is not necessary to hermetically seal the thermistor element 112 in the second mounting portion 111. .

The thermistor element 112 is mechanically fixed to the second mounting portion 111 by a fixing member 113.
As described above, the thermistor element 112 has an electrode for external connection (no symbol) on at least the lower surface at both ends of the element body, and this electrode is the second external connection terminal in the mounting structure. Acts as 115. The thermistor element 112 functions to sense the temperature of the piezoelectric vibration element 107 and transmit it to an external temperature compensation circuit. Therefore, it is sufficient that the thermistor element 112 is electrically connected to an external electric circuit (not shown) having a function such as temperature compensation. Therefore, the thermistor element 112 (electrode) and the piezoelectric vibration element 107 are not electrically connected inside and outside the insulating base 101.

Examples of the fixing member 113 include silicon resin, epoxy resin, and glass that are excellent in thermal conductivity and heat resistance with the insulating base 101. The fixing member 113 may be formed so as to fill a gap between the thermistor element 112 and the insulating base 101 as necessary.

In addition, a pair of dummy electrodes (not shown) is formed on the main surface of the second mounting portion 111, and the second external connection terminal 115 of the thermistor element 112 is fixed to the pair of dummy electrodes with a brazing material such as solder. May be. In this case, the second external connection terminals 115 are formed on the upper and lower surfaces of both end portions of the thermistor element 112 so that they do not melt at the reflow temperature of the solder used for mounting on the external circuit board (not shown). It is desirable to use high temperature solder or the like. As described above, the thermistor element 112 having the second external connection terminal 115 formed on at least the lower surface at at least both end portions of the element body is bonded to the insulating base 101 to basically form the mounting structure of the embodiment. ing. The thermistor element 112 will be described in detail later.

In the example of this embodiment, as described above, the pair of second external connection terminals 115 is provided on the lower surface of the thermistor element 112, and the second mounting portion 111 is sandwiched between the lower surface of the insulating base 101. A pair of leg portions 104 is provided, and a first external connection terminal 114 connected to the piezoelectric vibration element 107 is provided on the lower end surface of the pair of leg portions 104.

With such a structure, it is not necessary to separately provide an external connection terminal (not shown) connected to the thermistor element 112 on the lower surface of the insulating base 101, and a mounting structure capable of further space saving can be provided. .

The thermistor element 112 which is a part of the mounting structure of this embodiment is in a chip shape, and the thermistor element 112 is mounted in the vicinity of the piezoelectric vibration element 107 in order to perform accurate temperature compensation. It becomes possible to detect a temperature change at a position closer to 107.

  Such a mounting structure is a piezoelectric device in which the piezoelectric vibration element 107 is mounted on the first mounting portion 105 on the upper surface of the insulating base 101. In this piezoelectric device, the piezoelectric vibration element 107 is disposed so as to overlap the thermistor element 112 in plan view, and the second mounting portion 111 on which the thermistor element 112 is mounted extends to the outer peripheral edge of the insulating base 101. As a result, the mounting space can be further reduced.

In the chip-like thermistor element 112, for example, second external connection terminals 115 are formed at both ends of a thermistor body (element body) (not indicated). If the thermistor element is an NTC (negative temperature coefficient) type, it is formed of a thermistor material such as a Mn—Co—Cu-based material or a Mn—Co—Fe-based material. Further, if the thermistor element is a PTC (positive temperature coefficient) type, it is made of a thermistor material such as a Ba—Ti—O-based material.

If the thermistor element 112 is a laminated thermistor element, the structure in which a plurality of internal electrodes (not shown) are laminated, compared to a chip-type thermistor element that does not have internal electrodes inside the ceramic body. Therefore, the resistance can be reduced. That is, the plurality of internal electrodes formed inside the ceramic body and the second external connection terminal 115 as an external connection electrode connected to one end of the internal electrode and formed at both ends of the ceramic body. And have. That means
Since the ceramic body is formed by alternately laminating a plurality of ceramic layers and internal electrode layers, the resistance can be reduced. Therefore, since the high accuracy of the resistance value with respect to the temperature change can be obtained, the power consumption as the device can be suppressed.

In addition, since the second external connection terminal 115 which is an electrode of the thermistor element 112 can be directly joined to a connection conductor (not shown) of an external electric circuit such as a circuit board, the leg portion 104 of the insulating base 101 has a piezoelectric vibration element. Only a pair of first external connection terminals 114 connected to 107 need be formed. Therefore, the second external connection terminal 115 and the first external connection terminal 114 of the thermistor element 112 can be formed with a wide area, the connection conductor of the thermistor element 112 and the external electric circuit, and the insulating base 101 and the external electric circuit are provided. It is possible to improve the connection strength with an insulating substrate (not shown).

A pair of connection conductors 106 connected to the piezoelectric vibration element 107, a wiring conductor (not shown) formed via the inside or the outer periphery of the insulating base 101, and a first formed on the lower surface of the leg 104. The external connection terminal 114 is electrically connected, and the mounting structure (insulating base 101) is connected to a connection conductor with the external electric circuit.

On the other hand, as described above, the thermistor element 112 functions to sense the temperature of the piezoelectric vibration element 107 and transmit it to an external temperature compensation circuit. The thermistor element 112 and the piezoelectric vibration element are provided inside and outside the insulating base 101. 107 is not electrically connected. Therefore, the thermistor element 112 has a structure that is mechanically bonded to the insulating substrate 101. When connecting the mounting structure (insulating base 101) to the connection conductor with the external electric circuit, the second external connection terminal 115 formed on at least the lower surface of both ends of the thermistor element 112 is the center on the long side of the insulating base 101. In the vicinity, it is connected to a connection conductor with an external electric circuit. Further, the thermistor element 112 and the piezoelectric vibration element 107 are not electrically connected inside and outside the insulating base 101, so that the effect of reducing noise and suppressing electrical mutual interference between the components is obtained. is there. Further, by making one second external connection terminal 115 of the thermistor element 112 conductive with the lid 116 made of metal as a ground potential, it is possible to enhance the shielding effect against external noise.

The two first external connection terminals 114 of the insulating base 101 and the two second external connection terminals 115 of the thermistor element 112 are firmly connected to a connection conductor with an external electric circuit. Furthermore, since the piezoelectric vibration element 107 and the thermistor element 112 that do not function directly on the same insulating base 101 can be mounted with an electrically independent structure, it is possible to manufacture equipment with a reduced number of parts. Become.

In the example shown in FIG. 2, the distance between the pair of leg portions 104 is larger than the central portion in the outer peripheral portion of the insulating base 101 in the bottom view. In the case of such a structure, the first external connection terminal 114 formed on the leg portion 104 connected to the piezoelectric vibration element 107 and the second external connection formed on at least the lower surface of both end portions of the thermistor element 112. It is possible to more reliably suppress a short circuit between the terminal 115 and the spread of solder.

That is, the first external connection terminal 114 formed on the leg 104 has a planar shape, whereas the second external connection terminal 115 of the thermistor element 112 is formed on at least the lower surface, and the laminated layer as described above. In the case of the die chip thermistor element, the second external connection terminals 115 are integrally formed on the five surfaces at both ends. Therefore, there is a case where solder (not shown) rises to the insulating base 101 for joining the second external connection terminal 115 and the external circuit board. Even if the solder creeps up as described above, the distance between the pair of leg portions 104 is larger than the central portion in the outer peripheral portion of the insulating base 101 in the bottom view as described above. A short circuit between the first external connection terminal 114 and the second external connection terminal 115 due to spreading can be suppressed.

Specifically, as shown in FIG. 2, the second external connection terminal 115 of the thermistor element 112 in the leg portion 104.
The notches 117 may be formed in the four regions close to. As a method for forming such a notch 117, a part of the ceramic green sheet is appropriately punched to form the frame part 103, and the part of the ceramic green sheet to be the leg part 104 is cut. A region to be the notch 117 may be punched into a long hole shape, and then a suitable punching process may be performed to form the leg portion 104 to form a long hole shape.

After this punching process, a ceramic green sheet in which a frame-shaped ceramic green sheet is formed on the upper surface of a flat ceramic green sheet, and a long hole including a plurality of notches 117 is formed on the lower surface of the flat ceramic green sheet The insulating base 101 including the frame portion 103 and the leg portion 104 (having the notch portion 117) can be manufactured by laminating the sheets so as to be positioned and firing the laminated body at a high temperature.

In this case, the end of the notch 117 is formed toward the center of the insulating base 101 beyond the boundary between the second external connection terminal 115 formed at both ends of the thermistor element 112 and the element body of the thermistor element 112. It is good to have a structured. This is because the closer to the region closer to the end face of the thermistor element 112 where the solder fillet is formed and the volume of the solder increases, the distance between the first external connection terminal 114 and the second external connection terminal 115 by the notch 117 becomes larger. This is because it can be gradually increased and the short circuit can be more effectively suppressed.

In the example as shown in FIG. 3, the width of the second external connection terminal 115 is smaller than the central portion in the outer peripheral portion of the insulating base 101 when viewed from the bottom. In the case of such a structure, the first external connection terminal 114 formed on the leg portion 104 connected to the piezoelectric vibration element 107 and the second external connection formed on at least the lower surface of both end portions of the thermistor element 112. It is possible to prevent the terminal 115 from being short-circuited due to the spread of solder.

That is, the first external connection terminal 114 formed on the leg 104 has a planar shape, whereas the second external connection terminal 115 of the thermistor element 112 is formed on at least the lower surface, and the laminated layer as described above. In the case of a mold chip thermistor element, the second external connection terminals 115 are integrally formed on the five surfaces of both end portions, so that solder rises (not shown) for joining may occur. Even when the solder creeps up as described above, the width of the first external connection terminal 114 is smaller than the central portion in the outer peripheral portion of the insulating base 101 in the bottom view, and thus the first due to the spreading of the solder. A short circuit between the external connection terminal 114 and the second external connection terminal 115 can be suppressed.

Specifically, as shown in FIG. 3, a paste made of a metal material such as tungsten (metal paste) serving as the first external connection terminal 114 is printed in a predetermined pattern on the upper surface of the ceramic green sheet serving as the leg portion 104 and simultaneously. It can be formed by firing. In this case, the region of the first external connection terminal 114 close to the thermistor element 112 is made to be closer to the insulating substrate 101 than the boundary between the second external connection terminal 115 formed at both ends of the thermistor element 112 and the element body of the thermistor element 112. It is good to make it the structure formed near the center of. In this case, the distance between the first external connection terminal 114 and the second external connection terminal 115 on the mounting surface can be gradually increased as the area closer to the end face of the thermistor element 112 where the solder fillet is formed and the volume of the solder increases. This is because the short circuit can be more effectively suppressed.

In the example of the piezoelectric device as shown in FIGS. 1 to 3, the mounting structure and the first mounting portion 105 are used.
And a piezoelectric vibration element 107 that is electrically connected to the first external connection terminal 114. With such a structure, a piezoelectric device capable of further space saving can be provided. In addition, since the electrode (second external connection terminal 115) of the thermistor element 112 can be directly joined to an external electric circuit such as a circuit board, a piezoelectric device having excellent temperature compensation accuracy can be provided.

That is, since the electrode of the thermistor element 112 is used as it is as a terminal for external connection, it is not necessary to separately provide an external connection terminal for the thermistor element 112 on the lower surface of the insulating base 101. Therefore, it is possible to provide a piezoelectric device capable of further space saving.

Further, it is easy to reduce the conduction resistance between the thermistor element 112 and an external electric circuit (not shown), which is effective for improving the accuracy of temperature compensation.

In addition, since the electrode (first external connection terminal 114) for the piezoelectric vibration element 107 formed on the leg 104 can be formed in a wider area, an electrode (not shown) of an external electric circuit such as a circuit board and the insulating base 101 are used. The first external connection terminal 114 can be firmly joined.

Here, if the thermistor element 112 is a multilayer chip thermistor element as described above,
Due to the structure in which a plurality of internal electrodes (not shown) are stacked, the resistance can be reduced compared to a chip-type thermistor element that does not have internal electrodes inside the ceramic body. Therefore, it is possible to realize a piezoelectric device that can obtain high accuracy in resistance value against temperature change and suppresses power consumption.

As shown in FIG. 1B, the first external connection terminal 114 formed on the lower surface of the leg 104 and the second external connection terminal 115 formed on at least the lower surface of the thermistor element 112 are basically the same. It arrange | positions so that it may become planar shape. However, since the thickness (height) of the leg 104 and the thickness (height) of the thermistor element 112 change during the manufacturing process, the second external connection terminal 115 is more than the first external connection terminal 114 of the leg 104. What is necessary is just to make arrangement | positioning design so that it may be located upwards so that there may be no trouble in joining of solder. Thus, the height at which the thermistor element 112 is positioned above may be within 30 μm. As a result, there is no hindrance to solder bonding, and a solder reservoir is formed in a gap between an electrode (not shown) of an external electric circuit such as a circuit board and the second external connection terminal of the thermistor element 112, and the thermistor element 112 is formed. Can be made strong. The piezoelectric device can be stably mounted on the external circuit board by the pair of legs 104.

Further, the thermistor element 112 and the piezoelectric vibration element 107 are not electrically connected in the insulating base 101. Examples of the fixing member 113 that mechanically fixes the thermistor element 112 and the piezoelectric vibration element 107 include silicon resin and glass having excellent thermal conductivity and heat resistance with the insulating base 101. When the fixing member 113 is insulative such as silicon resin or glass, even if a part of the joint portion covers the second external connection terminal 115 in the region where the second mounting portion 111 and the thermistor element 112 face each other, There is no particular problem as long as it does not hinder the electrical connection between the second external connection terminal 115 and the electrode of the external electric circuit. If the bonding region is wider, the thermistor element 112 can be firmly bonded to the second mounting portion 111. The fixing member 113 may be formed so as to fill a gap between the thermistor element 112 and the insulating base 101 as necessary.

In addition, a pair of dummy electrodes (not shown) is formed on the main surface of the second mounting portion 111, and the second external connection terminal 115 of the thermistor element 112 is fixed to the pair of dummy electrodes with a brazing material such as solder. May be. In this case, the second external connection terminals 115 are formed on the upper and lower surfaces of both end portions of the thermistor element 112, and high temperature solder or the like that does not melt at the reflow temperature of the solder used for mounting on the external circuit board is used. It is desirable. At this time, if a region where the second external connection terminal 115 and the dummy electrode are fixed via solder is provided on the side surface of the leg 104 and the side surface of the thermistor element 112, the thermistor element corresponding to the thickness of the joining member 113 is provided. The accommodation depth of 112 can be reduced, which is advantageous in reducing the thickness of the piezoelectric device.

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, the leg 104 in the above embodiment
Is not necessarily required. As shown in FIGS. 4A and 4B, the lower surface of the insulating base 101 is provided with a convex portion 118 such as a U-shape or a frame shape in a plan view. An external connection terminal 114 may be provided. 4A and 4B are bottom views of the third and fourth modifications of the mounting structure shown in FIG. 1, respectively. 4, parts similar to those in FIG. 1 are denoted by the same reference numerals. The convex portion 118 is made of the same material as the leg portion 104, for example, and is formed by the same method.

In the case of the example as shown in FIG. 4A, the thermistor element 112 is more easily aligned with the second mounting portion 111 by pressing the thermistor element 112 against the end of the convex portion 118, for example. When the thermistor element 112 is pressed against the end of the convex portion 118, the shape of the end in plan view is such that a certain amount of gap is formed between the end and the second external connection terminal 115, such as an arc shape. Shape is preferred. As a result, the solder can be retained in the gap portion, and the flow of solder to the lower end surface of the convex portion 118 and the like is more effectively suppressed. Note that the end of the convex portion 118 may be a straight line instead of an arc. In this case, the convex portion 118 can be easily formed, which is advantageous in terms of productivity as a mounting structure.

In the case of the example as shown in FIG. 4B, the thermistor element 112 is more reliably protected. However, in terms of miniaturization of the mounting structure and the piezoelectric device, a configuration having a pair of legs as in the example of the above embodiment is preferable.

In the example of the above-described embodiment, the insulating base is formed by laminating one frame portion 103 (insulating layer) on the upper side of the flat plate-like base 102 and joining the metal frame body 110 on the upper surface thereof for the first mounting. Although the portion 105 is formed, the first mounting portion 105 may be formed by simply joining a metal frame (not shown) to the upper surface of the flat insulating layer. In addition, although the electronic component joined to the second mounting portion 111 is only the thermistor element, other elements such as a capacitor element, a resistor element, a diode element, etc. that do not need to be connected to the piezoelectric vibration element 107 in the piezoelectric device due to the circuit configuration. It may be a chip-shaped electronic component.

101 ... Insulating substrate
102 ... Base
103 ・ ・ ・ Frame part
104 ... Leg
105 ... 1st mounting part
106 ・ ・ ・ Connection conductor
107 ・ ・ ・ Piezoelectric vibration element
108 ・ ・ ・ Joint material
109 ・ ・ ・ Frame metallization layer
110 ・ ・ ・ Metal frame
111 ・ ・ ・ Second mounting part
112 ・ ・ ・ Thermistor element
113 ・ ・ ・ Fixing member
114 ... 1st external connection terminal
115 ... Second external connection terminal
116 ... lid
117 ・ ・ ・ Notch
118 ... convex

Claims (5)

An element mounting container including an insulating base, the insulating base including an upper surface including a first mounting portion on which the piezoelectric vibration element is mounted and a lower surface including a second mounting portion;
A thermistor element provided in the second mounting portion,
The element mounting container further includes a first external connection terminal provided on the lower surface of the insulating base,
The thermistor element includes an element main body bonded to the insulating base and a second external connection terminal provided on a lower surface of the element main body. The said insulation base | substrate further contains a pair of leg part which pinches | interposes the thermistor element, The said 1st external connection terminal is provided in the lower end surface of this pair of leg part. Implementation structure. The mounting structure according to claim 2, wherein a distance between the pair of leg portions is larger than a center portion in an outer peripheral portion of the insulating base in a bottom view. 3. The mounting structure according to claim 2, wherein the width of the first external connection terminal is smaller than the central portion in the outer peripheral portion of the insulating base in a bottom view. A mounting structure according to any one of claims 1 to 4;
A piezoelectric device comprising: a piezoelectric vibration element mounted on the first mounting portion and electrically connected to the first external connection terminal.

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