JP7435132B2 - piezoelectric oscillator - Google Patents

Description

The present invention relates to piezoelectric oscillators.

As a piezoelectric oscillator such as a crystal oscillator, a constant temperature piezoelectric oscillator that outputs a highly stable frequency without being affected by external temperature changes has been known (for example, see Patent Document 1).

Japanese Patent Application Publication No. 2010-177732

In the constant-temperature piezoelectric oscillator of Patent Document 1, a piezoelectric vibrator (a piezoelectric vibrating piece) is housed in a vibrator package and hermetically sealed, and the piezoelectric vibrator is placed inside a package consisting of a base substrate and a cover body. It is stored.

In this constant-temperature piezoelectric oscillator, the piezoelectric vibrating piece of the piezoelectric vibrator is hermetically sealed in a vibration package. Not hermetically sealed.

Therefore, the piezoelectric vibrating piece is susceptible to external temperature changes, etc., and there is a problem that the oscillation characteristics of the piezoelectric oscillator fluctuate.

The present invention has been made in view of the above points, and an object of the present invention is to reduce as much as possible characteristic fluctuations caused by external temperature changes and the like.

In order to achieve the above object, the present invention is configured as follows.

That is, the piezoelectric oscillator of the present invention includes a piezoelectric vibrator whose vibrating part is hermetically sealed, a heating element that heats the piezoelectric vibrator, an integrated circuit element forming an oscillation circuit, and at least the piezoelectric vibrator. Equipped with a package body that is hermetically sealed,
The package body includes at least a first package hermetically sealing the piezoelectric vibrator and a second package housing the integrated circuit element,
The first package includes a base in which a housing recess for housing the piezoelectric vibrator is formed on one of the upper and lower surfaces, and the second package has a housing recess for housing the integrated circuit element. , comprising a substrate formed on one of the upper and lower surfaces,
The other of the upper and lower surfaces of the base of the first package is joined to the other of the upper and lower surfaces of the substrate of the second package .

According to the present invention, the piezoelectric vibrator whose vibrating part is hermetically sealed is hermetically sealed in the package body, so the vibrating part of the piezoelectric vibrator is doubly hermetically sealed. As a result, it is possible to suppress the influence of external temperature changes on the vibrating part of the piezoelectric vibrator, and even if the external temperature changes, the characteristic fluctuations of the piezoelectric oscillator are suppressed and the oscillation frequency is stabilized. be able to.
Further, according to the present invention, the piezoelectric vibrator is individually housed in the first package, and the integrated circuit element is housed in the second package, so that the influence of the integrated circuit element on the piezoelectric vibrator can be suppressed.

In a preferred embodiment of the piezoelectric oscillator of the present invention, the piezoelectric vibrator includes a piezoelectric diaphragm having excitation electrodes formed on both principal surfaces, and a piezoelectric diaphragm that covers and seals the excitation electrode on one principal surface of the piezoelectric diaphragm. and a second sealing member that covers and seals the excitation electrode on the other main surface of the piezoelectric diaphragm, and the piezoelectric diaphragm has a bonding metal on both main surfaces. The first sealing member has a bonding metal film corresponding to the bonding metal film on the one main surface of the piezoelectric diaphragm, and the second sealing member has a bonding metal film corresponding to the bonding metal film on the one main surface of the piezoelectric diaphragm. a bonding metal film corresponding to the bonding metal film on the other main surface of the piezoelectric diaphragm; the first sealing member and the piezoelectric diaphragm are bonded by the bonding metal film; The second sealing member and the piezoelectric diaphragm are bonded by the bonding metal film, and the vibrating section including the excitation electrodes on both main surfaces of the piezoelectric diaphragm is connected to the first sealing member and the piezoelectric diaphragm. Hermetically sealed by the second sealing member.

According to this embodiment, the piezoelectric vibrator includes a piezoelectric diaphragm in which excitation electrodes are formed on both principal surfaces, a first sealing member that covers and seals the excitation electrode on one principal surface, and a first sealing member that covers and seals the excitation electrode on one principal surface. A second sealing member that covers and seals the excitation electrode on the surface is laminated by bonding the bonding metal films to each other. Therefore, it is necessary to use a conductive adhesive, such as a package structure in which the piezoelectric vibrating piece is housed in a container having a housing recess, and the piezoelectric vibrating piece is hermetically sealed by being bonded to an electrode in the container using a conductive adhesive. do not have. This eliminates the influence of gas generated from the conductive adhesive and stabilizes the frequency characteristics.

Furthermore, since the piezoelectric vibrator has a three-layer laminated structure of the piezoelectric diaphragm and the first and second sealing members, it can be made thinner (lower in height) than the package structure described above.

In another embodiment of the piezoelectric oscillator of the present invention, the second package has a larger planar size than the first package, and is joined to an outer peripheral part of the second package to accommodate the first package. A cover body that constitutes a space is provided.

According to this embodiment, the piezoelectric vibrator whose vibrating part is hermetically sealed is hermetically sealed by the first package, and the first package is housed in the housing space formed by the second package and the cover body. Therefore, the vibrating part of the piezoelectric vibrator is double hermetically sealed and housed in the housing space formed by the second package and the cover body. This makes it possible to insulate the vibrating part of the piezoelectric vibrator and effectively suppress the influence of external temperature changes.

In one embodiment of the present invention, the heating element is a heater substrate or a film heater bonded to the piezoelectric vibrator, and the package body hermetically seals the heater substrate together with the piezoelectric vibrator.

According to this embodiment, since the heater substrate or the film heater is bonded to the piezoelectric vibrator, the piezoelectric vibrator can be efficiently heated.

In another embodiment of the present invention, the first package has a sealed space that accommodates and hermetically seals the piezoelectric vibrator, and the base of the first package includes a substrate portion and an outer periphery of the substrate portion. the sealed space includes the base of the first package and a lid joined to the frame of the base ; , the heating element is provided.

According to this embodiment, the sealed space in which the piezoelectric vibrator is sealed can be heated by the heating element provided in the substrate section.

In a preferred embodiment of the present invention, a temperature sensor is provided, and the integrated circuit element controls heat generation of the heating element based on the temperature detected by the temperature sensor.

According to this embodiment, the temperature of the piezoelectric vibrator can be controlled to be constant by controlling the heat generation of the heating element based on the temperature detected by the temperature sensor.

According to the present invention, since the piezoelectric vibrator whose vibrating part is hermetically sealed is hermetically sealed in the package body, the vibrating part of the piezoelectric vibrator is doubly hermetically sealed, and the piezoelectric vibrator The influence of external temperature changes etc. on the vibrating part of the child can be suppressed, and even if the external temperature etc. change, characteristic fluctuations of the piezoelectric oscillator can be suppressed.

FIG. 1 is a schematic configuration diagram of a crystal oscillator according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of the crystal resonator of FIG. 1. FIG. 3 is a schematic plan view of both main surfaces of the crystal diaphragm. FIG. 4 is a schematic plan view of both main surfaces of the first sealing member. FIG. 5 is a schematic plan view of both sides of the second sealing member. FIG. 6 is a schematic plan view of the second substrate. FIG. 7 is a schematic plan view of the first package mounted on the second substrate. FIG. 8 is a schematic configuration diagram of another embodiment of the present invention. FIG. 9 is a schematic configuration diagram of still another embodiment of the present invention. 10 is a schematic plan view of the heater substrate of FIG. 9. FIG. FIG. 11 is a schematic configuration diagram of another embodiment of the present invention. FIG. 12 is a schematic configuration diagram of a reference example of the present invention. FIG. 13 is a schematic configuration diagram of another reference example of the present invention.

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings. In this embodiment, the piezoelectric oscillator is applied to a constant temperature oven type crystal oscillator.

FIG. 1 is a schematic diagram of a constant temperature oven type crystal oscillator according to an embodiment of the present invention.

A crystal oscillator 1 of this embodiment includes a crystal oscillator 2, an IC chip 3 as an integrated circuit element, a package body 4 accommodating them, and a heater 5 as a heating element that heats the crystal oscillator 2. ing.

The package body 4 includes a first package 6 that hermetically seals the crystal resonator 2, and a second package 7 that accommodates the IC chip 3 and forms a housing space that accommodates the first package 6. .

The first package 6 includes a base 8 which is open at the top and has an accommodation recess 8a for accommodating the crystal resonator 2, and is joined to the base 8 via a seal ring 9 to close the upper opening and open the accommodation recess 8a. It is provided with a lid 10 as a lid part for airtight sealing.

The base 8 includes a flat substrate portion and an upper frame portion that protrudes upward from the outer periphery of the substrate portion to form an accommodation recess 8a. Hermetic sealing is performed in a vacuum atmosphere or an inert gas atmosphere such as nitrogen gas, and the space inside the first package 6 is kept in a vacuum or inert gas atmosphere.

The base 8 is made of a ceramic material such as alumina, and is constructed by laminating ceramic green sheets and firing them into a concave shape with an open top. A heater 5 for heating the crystal resonator 2 is embedded in the substrate portion of the base 8 so as to be sandwiched between ceramic green sheets. The heater 5 is made of a metal material such as nichrome, and generates heat due to electrical resistance when energized.

The second package 7 includes a first substrate 11, a second substrate 12 having an accommodation recess 12a on the lower surface side, and a cover that constitutes an accommodation space for accommodating the first package 6 and the second substrate 12 together with the first substrate 11. It is equipped with a body 13. A cover body 13 is bonded to the first substrate 11 so as to be covered therewith.

The first substrate 11 and the second substrate 12 are substantially rectangular in plan view, and are made of a ceramic material such as alumina, for example. The cover body 13 is made of an insulating material with low thermal conductivity, such as a resin material, so that the housing space is not affected by ambient temperature.

FIG. 2 is an enlarged cross-sectional view of the crystal resonator 2 of FIG. This crystal resonator 2 includes a crystal diaphragm 14 that is a piezoelectric diaphragm, a first sealing member 15 that covers and airtightly seals one main surface side of the quartz diaphragm 14, and the other side of the quartz diaphragm 14. and a second sealing member 16 that covers and airtightly seals the main surface side.

In this crystal resonator 2, first and second sealing members 15 and 16 are respectively bonded to both main surfaces of a crystal diaphragm 14, thereby forming a so-called sandwich structure package. The package of this crystal resonator 2 is a rectangular parallelepiped, and is rectangular in plan view. The package size of the crystal resonator 2 of this embodiment is, for example, 1.0 mm x 0.8 mm in plan view, and is intended to be smaller and lower in height.

Note that the package size is not limited to the above, and different sizes are also applicable.

Next, each structure of the crystal diaphragm 14 and the first and second sealing members 15 and 16 that constitute the crystal resonator 2 will be explained.

3(a) is a schematic plan view showing one main surface side of the crystal diaphragm 14, and FIG. 3(b) shows the other main surface side seen through from one main surface side of the crystal diaphragm 14. FIG.

The crystal diaphragm 14 of this embodiment is an AT-cut crystal plate, and both principal surfaces thereof are XZ' planes.

The crystal diaphragm 14 includes a substantially rectangular vibrating part 20, an outer frame part 22 surrounding the vibrating part 20 with a space (gap) 21 in between, and a connection connecting the vibrating part 20 and the outer frame part 22. 23. The vibrating section 20, the outer frame section 22, and the connecting section 23 are integrally formed. Although not shown, the vibrating section 20 and the connecting section 23 are formed thinner than the outer frame section 22.

A pair of first and second excitation electrodes 24 and 25 are formed on both main surfaces of the vibrating section 20, respectively. First and second extraction electrodes 26 and 27 are extended from the first and second excitation electrodes 24 and 25, respectively. The first lead-out electrode 26 on one main surface side is drawn out to a connecting bonding pattern 28 formed on the outer frame part 22 via the connecting part 23 . The second lead-out electrode 27 on the other main surface side is drawn out to the connecting bonding pattern 30 formed on the outer frame part 22 via the connecting part 23 .

A first sealing joining pattern 31 as a joining metal film for joining the crystal diaphragm 14 to the first sealing member 15 is provided on one main surface of the crystal diaphragm 14 over the entire outer frame portion 22. It is formed in an annular shape so as to substantially follow the outer peripheral edge of the crystal diaphragm 14 over the circumference. A second sealing bonding pattern 32 as a bonding metal film for bonding the crystal plate 14 to the second sealing member 16 is provided on the other main surface of the crystal plate 14 over the entire outer frame portion 22. It is formed in an annular shape so as to substantially follow the outer peripheral edge of the crystal diaphragm 14 over the circumference.

A first through electrode 29 is formed in the crystal diaphragm 14 and penetrates between both main surfaces. The first through electrode 29 is configured by depositing a metal film on the inner wall surface of the through hole. The first through electrode 29 is formed inside the annular first and second sealing bonding patterns 31 and 32 on the outer frame portion 22 near one short side of the crystal diaphragm 14 which is rectangular in plan view. ing. The connection bonding pattern 28 extends around the first through electrode 29 on one main surface side of the crystal diaphragm 14 and is connected to the first extraction electrode 26 extended from the first excitation electrode 24 . The first through electrode 29 is electrically connected to the connection bonding pattern 28 , and therefore the first through electrode 29 is electrically connected to the first excitation electrode 24 .

First and second excitation electrodes 24 and 25, first and second extraction electrodes 26 and 27, first and second sealing bonding patterns 31 and 32, and connection bonding patterns 28 and 30 of the crystal diaphragm 14 is constructed by laminating, for example, Au on a base layer made of, for example, Ti or Cr.

4(a) is a schematic plan view showing one main surface side of the first sealing member 15, and FIG. 4(b) is a schematic plan view showing the other main surface side of the first sealing member 15. FIG. 3 is a schematic plan view showing the surface side.

The first sealing member 15 is a rectangular parallelepiped substrate made of an AT-cut crystal plate similar to the crystal diaphragm 14 . The other main surface of the first sealing member 15 is bonded to the first sealing bonding pattern 31 on one main surface of the crystal diaphragm 14 for sealing, as shown in FIG. 4(b). A first sealing bonding pattern 33 serving as a bonding metal film for the first sealing member 15 is formed in an annular shape approximately along the outer periphery of the first sealing member 15 over the entire circumference of the first sealing member 15. There is.

The first sealing bonding pattern 33 is formed by laminating, for example, Au on a base layer made of, for example, Ti or Cr.

5(a) is a schematic plan view showing one main surface side of the second sealing member 16, and FIG. 5(b) is a schematic plan view showing the other main surface side of the second sealing member 16. FIG. 3 is a schematic plan view showing the surface side.

The second sealing member 16 is a rectangular parallelepiped substrate made of an AT-cut crystal plate similar to the crystal diaphragm 14 and the first sealing member 15 .

As shown in FIG. 5(a), one main surface of the second sealing member 16 is provided for bonding and sealing to the second sealing bonding pattern 32 on the other main surface of the crystal diaphragm 14. A second sealing bonding pattern 34 as a bonding metal film is formed in an annular shape approximately along the outer periphery of the second sealing member 16 over the entire circumference of the second sealing member 16. There is.

In the second sealing member 16, two second and third through electrodes 42 and 43 penetrating between both main surfaces thereof are formed inside the annular second sealing bonding pattern 34. Each of the through electrodes 42 and 43 is constructed by depositing a metal film on the inner wall surface of the through hole.

On one short side of the annular second sealing bonding pattern 34 of the second sealing member 16 , a connecting bonding pattern 37 is attached to the first through electrode 29 on the other main surface of the crystal diaphragm 14 . It is formed to correspond to. By joining the crystal diaphragm 14 and the second sealing member 16 as described below, the first through electrode 29 is joined to the connection joining pattern 37 and electrically connected. The first through electrode 29 is electrically connected to the first excitation electrode 24 of the crystal diaphragm 14, as shown in FIG. 3(a). Therefore, the connection bonding pattern 37 on one main surface of the second sealing member 16 is electrically connected to the first excitation electrode 24 through the bonding between the crystal diaphragm 14 and the second sealing member 16 .

This connection bonding pattern 37 is electrically connected to the second through electrode 42 near the other short side via the connection wiring pattern 36, as shown in FIG. 5(a). Therefore, the second through electrode 42 is formed by joining the crystal diaphragm 14 and the second sealing member 16 to the connection wiring pattern 36, the connection bonding pattern 37, the first through electrode 29 of the crystal diaphragm 14, and the connection wiring pattern 36, the connection bonding pattern 37, the It is electrically connected to the first excitation electrode 24 via the bonding pattern 28 and the first extraction electrode 26 .

The third through electrode 43 on one main surface of the second sealing member 16 is formed to correspond to the connection bonding pattern 30 on the other main surface of the crystal diaphragm 14 . The connection bonding pattern 30 on the other main surface of the crystal diaphragm 14 is electrically connected to the second excitation electrode 25, as shown in FIG. 3(b). Therefore, by joining the crystal diaphragm 14 and the second sealing member 16 as described below, the third through electrode 43 of the second sealing member 16 can be connected to the connection bonding pattern 30 of the crystal diaphragm 14, It is electrically connected to the second excitation electrode 25 via the second extraction electrode 27 .

As shown in FIG. 5(b), a pair of first and second external connection terminals 40 and 41 for electrical connection to the outside are provided on the other main surface of the second sealing member 16. There is. The first and second external connection terminals 40 and 41 extend along the short side direction at both ends of the second sealing member 16 in the long side direction.

The first and second external connection terminals 40 and 41 are electrically connected to the second and third through electrodes 42 and 43, respectively. The second and third through electrodes 42 and 43 are electrically connected to the first and second excitation electrodes 24 and 25 of the crystal diaphragm 14, respectively, as described above, so the first and second external connection terminals 40 and 41 are electrically connected to the first and second excitation electrodes, respectively.

The second sealing bonding pattern 34, the connection bonding pattern 37, the connection wiring pattern 36, and the first and second external connection terminals 40 and 41 of the second sealing member 16 are made of, for example, Ti or Cr. For example, Au is laminated on the base layer.

In the crystal resonator 2 of this embodiment, the crystal diaphragm 14 and the first sealing member 15 are diffusion-bonded with their respective first sealing bonding patterns 31 and 33 superimposed, and the crystal oscillation The plate 14 and the second sealing member 16 are diffusion-bonded with their respective second sealing bonding patterns 32 and 34 superposed one on top of the other, thereby producing a sandwich-structured package shown in FIG. 1. As a result, the accommodation space in which the vibrating section 20 of the crystal diaphragm 14 is accommodated is hermetically sealed by both the sealing members 15 and 16.

In this way, the package containing the vibrating section 20 is constructed by laminating the three crystal plates of the crystal diaphragm 14 and the first and second sealing members 15 and 16. The crystal resonator can be made thinner (lower in height) than a crystal resonator in which a crystal resonator piece is housed in a container made of aluminum and sealed with a lid.

In the crystal resonator 2, the first and second external connection terminals 40 and 41 of the second sealing member 16 are connected to the inner bottom surface of the base 8 of the first package 6 shown in FIG. It is mounted by being joined to a resonator connection terminal (not shown) formed in the .

A plurality of external connection terminals are provided on the bottom surface of the first package 6, that is, on the outer bottom surface of the base 8. These external connection terminals are connected to the vibrator connection terminals connected to the first and second excitation electrodes 24 and 25 of the crystal resonator 2 and to the heater 5 via internal wiring of the base 8 .

FIG. 6 is a schematic plan view of the second substrate 12 of the second package 7 on which the first package 6 is mounted. A plurality of connection electrodes corresponding to a plurality of external connection terminals on the bottom surface of the first package 6 are formed on the upper surface of the second substrate 12 mounted on the first substrate 11 of the second package 7 . Specifically, on the upper surface of the second substrate 12, connection electrodes 50, 51 for the crystal resonator 2, connection electrodes 52 for the heater 5, and connection electrodes 53, 54, 55 for GND (ground) are provided. , connection electrodes 56 for peripheral circuit components such as capacitors and resistors are formed.

As shown in FIG. 7, the first package 6 and peripheral circuit components 62 such as capacitors and resistors are mounted on the second substrate 12 using a bonding material such as solder.

As shown in FIG. 1, the accommodation recess 12a for accommodating the IC chip 3 as described above is formed on the lower surface side of the second substrate 12. This housing recess 12a is closed by the first substrate 11 by mounting the second substrate 12 on the first substrate 11.

The accommodation recess 12a of the second substrate 12 is provided with a stepped portion higher than the bottom surface on the inner peripheral wall. A plurality of connection electrodes each consisting of a conductor wiring pattern for connecting the IC chip 3 is formed on the upper surface of this stepped portion.

The inactive surface (lower surface) of the IC chip 3 opposite to the active surface (upper surface) is bonded to the bottom surface of the accommodation recess 12a of the second substrate 12 with an adhesive. A plurality of electrode pads each connected to the connection electrodes of the second substrate 12 are formed on the active surface of the IC chip 3 at its periphery.

Each electrode pad of the IC chip 3 is electrically connected to a corresponding connection electrode formed on the step portion of the second substrate 12 by a bonding wire 47. The material for the bonding wire 47 is preferably Au from the viewpoint of reliability, but may also be made of Cu or the like.

The IC chip 3 is rectangular in plan view, and includes an oscillation circuit, a temperature sensor, and a temperature control circuit that controls heat generation of the heater 5 based on the temperature detected by the temperature sensor. This IC chip 3 is connected to the first and second excitation electrodes 24 and 25 of the crystal resonator 2 of the first package 6 and the heater 5 via internal wiring of the second substrate 12. The IC chip 3 also connects to a plurality of external terminals such as a power supply terminal, an output terminal, a control terminal, and a GND terminal on the bottom surface of the first substrate 11 via the internal wiring of the second substrate 12 and the internal wiring of the first substrate 11. It is connected to a connection terminal, that is, an external connection terminal for mounting the crystal oscillator 1 .

In the crystal oscillator 1 of this embodiment, the heat generation amount of the heater 5 is controlled by the IC chip 3, and the temperature of the crystal resonator 2 is controlled.

According to the crystal oscillator of this embodiment having the above configuration, the vibrating section 20 of the crystal diaphragm 14 is hermetically sealed by the first and second sealing members 15 and 16, and the crystal resonator 2 is Since the single package 6 is hermetically sealed, the periphery of the vibrating part 20 of the crystal diaphragm 14 can be extremely effectively insulated from the outside. As a result, it is possible to reduce the influence of external temperature changes, etc., and obtain a stable oscillation frequency.

The crystal resonator 2 also includes a crystal plate 14 on which first and second excitation electrodes 24 and 25 are formed on both principal surfaces, and a first sealing member 15 that covers and seals the first excitation electrode 24. , and the second sealing member 16 that covers and seals the second excitation electrode 25 are laminated by bonding their bonding metal films to each other, so that the crystal vibrating piece can be housed in a container having a housing recess. There is no need to use a conductive adhesive, unlike a package structure in which the container is connected to an electrode inside the container using a conductive adhesive and hermetically sealed with a lid. This stabilizes the frequency characteristics without being affected by the gas generated from the conductive adhesive.

Further, the crystal resonator 2 in which the vibrating section 20 is hermetically sealed is hermetically sealed by a first package 6, and this first package 6 is constituted by the first substrate 11 of the second package 7 and the cover body 13. Since the vibrating section 20 of the crystal resonator 2 is doubly hermetically sealed, it is also confined within the housing space. As a result, the vibrating section 20 of the crystal resonator 2 is triple-insulated, and the influence of external temperature changes can be effectively suppressed.

FIG. 8 is a schematic configuration diagram corresponding to FIG. 1 of another embodiment of the present invention.

In the crystal oscillator 1 ₁ of this embodiment, the base 8 ₁ of the first package 6 ₁ has an H cross-sectional structure having housing recesses 8 ₁ a and 8 ₁ b on both upper and lower surfaces, respectively.

The accommodation recess 8 ₁ a on the upper surface side of the base 8 ₁ accommodates the crystal oscillator 2, as in the above embodiment, and the accommodation recess 8 ₁ b on the lower surface side accommodates the heater 5 in place of the heater 5 of the above embodiment. A chip resistor 57 for heating the crystal resonator 2 is housed therein.

The other configurations are similar to the embodiment shown in FIG. 1 above.

FIG. 9 is a schematic configuration diagram corresponding to FIG. 1 of still another embodiment of the present invention.

In the crystal oscillator ₁₂ of this embodiment, a heater substrate 58 for heating the crystal resonator ₂ is bonded to the upper surface of the crystal resonator 2 accommodated in the accommodation recess _82a of the base 82. Note that a heater substrate for heating the crystal resonator 2 may be bonded not only to the upper surface of the crystal resonator 2 but also to the lower surface of the crystal resonator 2.

As shown in FIG. 10, this heater board 58 has a meandering resistance wiring 59 formed on a substrate 64 such as crystal, and both ends 59a, 59b of which are connected to the inner bottom surface of the base _82. It is electrically connected to the electrode by a bonding wire 60. For example, nichrome, chromium, tungsten, or the like is used for the resistance wiring 59.

Further, the first substrate 11 ₂ of the second package 7 ₂ has a cavity 61 formed on its upper surface side, and the contact area between the first substrate 11 ₂ and the second substrate 12, that is, the area of the heat conduction path. This suppresses heat radiation from the second substrate 12 to the first substrate ₁₁₂ . The cavity 61 may have any shape as long as it can reduce the area of the heat conduction path.

The other configurations are similar to the embodiment shown in FIG. 1 above.

According to this embodiment, since the heater substrate 58 is bonded to the crystal resonator 2, the crystal resonator 2 can be efficiently heated.

Note that instead of the heater substrate 58, for example, a film resistor in which a metal foil resistance pattern is formed on a polyimide film or the like may be used.

In each of the above embodiments, the cover body 13 of the second package 7 is bonded to the first substrate 11, but as another embodiment of the present invention, as shown in FIG. 11, the first substrate 11 is omitted, The cover body 13 ₃ may be joined to the second substrate 12 ₃ .

That is, in the crystal oscillator ₁₃ of this embodiment, the second package ₇₃ includes a second substrate ₁₂₃ on which the IC chip 3 is mounted, and an accommodation space that accommodates the first package 6 together with the second substrate ₁₂₃ . The first substrate ₁₁ is not provided.

In this embodiment, a plurality of external connection terminals connected to the IC chip ₃ , such as a power supply terminal, an output terminal, a control terminal, and a GND terminal, are provided on the bottom surface (lower surface) of the second substrate 123, that is, the crystal oscillator ₁₃ . External connection terminals for mounting are formed.

The other configurations are similar to the embodiment shown in FIG. 1 above.

In each of the above embodiments, the first packages 6, 6 ₁ and 6 ₂ are accommodated in the accommodation space constituted by the first substrates 11, 11 ₂ or the second substrates 12, 12 ₃ and the cover bodies 13, 13 ₃ . However, as another embodiment of the present invention, the second substrate 12, ₁₂₃ and the cover body 13, ₁₃₃ may be omitted, and the first package 6 may be exposed.

FIG. 12 is a schematic configuration diagram corresponding to FIG. 1 of a reference example of the present invention.

The crystal oscillator ₁₄ of this reference example includes a first package ₆₄ . The first package ₆₄ includes a base ₈₄ having an H cross-sectional structure and having housing recesses _84a and _84b on both upper and lower surfaces, respectively. The crystal resonator 2 is housed in the housing recess _84a on the upper side of the base ₈₄ , the IC chip 3 is housed in the housing recess _84b on the lower side, and the heater 5 is housed in the intermediate substrate part of the base ₈₄ . It has ₄ built-in.

A plurality of external connection terminals connected to the IC chip 3, such as a power supply terminal, an output terminal, a control terminal, and a GND terminal, are formed on the bottom surface (lower surface) of the base ₈₄ .

The other configurations are similar to the embodiment shown in FIG. 1 above.

According to this reference example , the second substrates 12, ₁₂₃ and the cover bodies 13, ₁₃₃ can be omitted, making it possible to reduce the size and thickness.

FIG. 13 is a schematic configuration diagram corresponding to FIG. 1 of another reference example of the present invention.

In the crystal oscillator ₁₅ of this reference example , the housing recess 85a of the base _{85 of the package body 65 has a stepped portion 85c formed on} the inner peripheral wall. The crystal resonator 2 is mounted on this stepped portion 8 ₅ c by being bonded with solder or the like. Furthermore, the IC chip 3 is flip-chip mounted on the inner bottom surface of the housing recess 8 ₅ a via metal bumps 63 .

A heater ₅₅ for heating the crystal resonator 2 is built into the bottom of the base ₈₅ .

According to this reference example , by housing the crystal resonator 2 and the IC chip 3 in the same housing recess _85a , the temperature of the crystal resonator 2 can be accurately measured by the built-in temperature sensor of the IC chip 3. The temperature of the crystal resonator 2 can be controlled with high precision.

In each of the above embodiments, crystal is used for the first and second sealing members 15 and 16, but the material is not limited to this, and other insulating materials such as glass may be used.

In the above embodiment, an AT-cut crystal is used for the crystal diaphragm 14, but the present invention is not limited to this, and a crystal other than an AT-cut crystal may be used.

In the embodiment described above, each of the through electrodes 29, 42, and 43 is configured by depositing a metal film on the inner wall surface of the through hole, but the present invention is not limited to this, and the through hole may be filled with a conductive material.

1,1 ₁ to 1 ₅ Crystal oscillator 2 Crystal resonator 3 IC chip (integrated circuit element)
4 ₁ to 4 ₃ Package body 5, _{5 4} , 5 ₅ Heater 6, 6 ₁ , 6 ₂ , 6 ₄ , 6 5 First package 7, _{7 2} , _{7 3 Second} package 14 Crystal diaphragm 15 First sealing Member 16 Second sealing member

Claims (7)

A piezoelectric vibrator whose vibrating part is hermetically sealed;
a heating element that heats the piezoelectric vibrator;
an integrated circuit element that constitutes an oscillation circuit;
a package body hermetically sealing at least the piezoelectric vibrator ;
The package body includes at least a first package hermetically sealing the piezoelectric vibrator and a second package housing the integrated circuit element,
The first package includes a base in which an accommodation recess for accommodating the piezoelectric vibrator is formed on one of the upper and lower surfaces,
The second package includes a substrate in which an accommodation recess for accommodating the integrated circuit element is formed on one of the upper and lower surfaces,
The other of the upper and lower surfaces of the base of the first package is joined to the other of the upper and lower surfaces of the substrate of the second package;
A piezoelectric oscillator characterized by: The piezoelectric vibrator includes a piezoelectric diaphragm having excitation electrodes formed on both principal surfaces, a first sealing member that covers and seals the excitation electrode on one principal surface of the piezoelectric diaphragm, and a first sealing member that covers and seals the excitation electrode on one principal surface of the piezoelectric diaphragm. a second sealing member that covers and seals the excitation electrode on the other main surface of the plate;
The piezoelectric diaphragm has bonding metal films on both main surfaces, and the first sealing member has a bonding metal film corresponding to the bonding metal film on the one main surface of the piezoelectric diaphragm. the second sealing member has a metal film for bonding that corresponds to the metal film for bonding on the other main surface of the piezoelectric diaphragm;
The first sealing member and the piezoelectric diaphragm are bonded by the bonding metal film, the second sealing member and the piezoelectric diaphragm are bonded by the bonding metal film, and the piezoelectric diaphragm The vibrating section including the excitation electrodes on both main surfaces of is hermetically sealed by the first sealing member and the second sealing member.
A piezoelectric oscillator according to claim 1. The second package has a larger planar size than the first package,
a cover body that is joined to an outer peripheral portion of the second package and forms a housing space that accommodates the first package;
A piezoelectric oscillator according to claim 1 or 2. The heating element is a heater substrate joined to the piezoelectric vibrator, and the package body hermetically seals the heater substrate together with the piezoelectric vibrator.
A piezoelectric oscillator according to any one of claims 1 to 3 . The heating element is a film heater joined to the piezoelectric vibrator, and the package body hermetically seals the film heater together with the piezoelectric vibrator.
A piezoelectric oscillator according to any one of claims 1 to 3. The first package has a sealed space that accommodates and hermetically seals the piezoelectric vibrator, and the base of the first package includes a substrate portion and a frame portion formed on the outer periphery of the substrate portion. wherein the sealed space is constituted by the base of the first package and a lid portion joined to the frame portion of the base, and the heating element is provided on the substrate portion of the base.
A piezoelectric oscillator according to any one of claims 1 to 3 . Equipped with a temperature sensor,
The integrated circuit element controls heat generation of the heating element based on the temperature detected by the temperature sensor.
A piezoelectric oscillator according to any one of claims 1 to 6 .

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