JP2021158585A - Piezoelectric oscillator - Google Patents

Abstract

To improve the reliability of the connection of integrated circuit elements in a piezoelectric oscillator.SOLUTION: A piezoelectric oscillator includes an insulating substrate with better flatness than ceramic and on which a wiring pattern is formed, a piezoelectric transducer, an integrated circuit element mounted on the insulating substrate, a heating element that heats the piezoelectric transducer, and a container that contains and hermetically seals the insulating substrate on which the integrated circuit element is mounted. The integrated circuit element has a plurality of electrode pads. The electrode pads are flip-chip connected to the wiring pattern of the insulating substrate via bumps.SELECTED DRAWING: Figure 1

Description

The present invention relates to a piezoelectric oscillator.

In a piezoelectric oscillator such as a crystal oscillator, the piezoelectric vibrator and the IC chip constituting the oscillation circuit are hermetically sealed in the package (see, for example, Patent Document 1).

In the piezoelectric oscillator of Patent Document 1, the IC chip is flip-chip mounted on the bottom surface of the package.

Japanese Unexamined Patent Publication No. 11-354587

In recent years, IC chips, which are integrated circuit elements, have become larger in size as the number of electrode pads has increased with the increase in functionality.

On the other hand, the package on which the IC chip is mounted is generally made of ceramic, and in such a ceramic package, when the size is increased, the bottom surface on which the IC chip is mounted is warped and the flatness is deteriorated.

Therefore, when the IC chip is flip-chip mounted on the bottom surface of the package by bumps, the bumps are not connected or the bumps are not connected in the plurality of electrode pads. Occasionally, when the load applied to the entire surface is increased, the flatness of the bottom surface is poor, so that the load applied between the electrode pads is different, and cracks may occur in the electrode pads to which a large load is applied.

The present invention has been made in view of the above points, and an object of the present invention is to improve the reliability of connection of integrated circuit elements in a piezoelectric oscillator.

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

That is, the piezoelectric oscillator of the present invention has an insulating substrate having a better flatness than ceramic and having a wiring pattern formed, a piezoelectric vibrator, and an integrated circuit mounted on the insulating substrate. The integrated circuit element includes a circuit element, a heating element that heats the piezoelectric vibrator, and a container that houses and airtightly seals the insulating substrate on which the integrated circuit element is mounted. The integrated circuit element has a plurality of electrodes. Along with having a pad, the electrode pad is flip-chip connected to the wiring pattern of the insulating substrate via bumps.

According to the present invention, an integrated circuit element having a plurality of electrode pads is flip-chip connected to a wiring pattern formed by an insulating substrate via bumps, but the insulating substrate is compared with ceramics. Since the flatness is good, the load applied at the time of mounting is suppressed from being dispersed among the plurality of electrode pads, stable connection is possible, and the reliability of connection of integrated circuit elements is improved.

In a preferred embodiment of the piezoelectric oscillator of the present invention, the insulating substrate is a quartz substrate or a glass substrate.

According to this embodiment, the insulating substrate made of a quartz substrate or a glass substrate has a better flatness than a flat surface made of ceramic such as a ceramic substrate or the inner bottom surface of a ceramic package. Therefore, when the integrated circuit element is flip-chip connected to the wiring pattern formed on the insulating substrate, the applied load is suppressed from being dispersed among the plurality of electrode pads, and stable connection is possible. It becomes.

In another embodiment of the piezoelectric oscillator of the present invention, the piezoelectric oscillator is mounted on the integrated circuit element mounted on the insulating substrate, and is housed in the container together with the insulating substrate. It is tightly sealed.

According to this embodiment, the piezoelectric vibrator is mounted on an integrated circuit element mounted on an insulating substrate, that is, the integrated circuit element and the piezoelectric vibrator are mounted on the insulating substrate in a laminated manner. Therefore, the area occupied by the integrated circuit element and the piezoelectric vibrator on the insulating substrate can be reduced as compared with mounting the integrated circuit element and the piezoelectric vibrator individually on the insulating substrate.

As a result, the plane size of the insulating substrate can be reduced by the amount of the occupied area to reduce the size, or other components can be mounted in the unoccupied area on the insulating substrate. can do.

In yet another embodiment of the piezoelectric oscillator of the present invention, the heating element is a heater substrate mounted on the piezoelectric vibrator mounted on the integrated circuit element, and the heater substrate is provided together with the insulating substrate. , It is housed in the container and airtightly sealed.

According to this embodiment, the integrated circuit element, the crystal oscillator, and the heating element can be housed in the same container and hermetically sealed, so that the influence of an external temperature change or the like can be suppressed. Therefore, even if the external temperature or the like changes, it is possible to suppress fluctuations in the characteristics of the piezoelectric oscillator and stabilize the oscillation frequency. Further, since the heater substrate as the heating element is mounted on the piezoelectric vibrator, the piezoelectric vibrator can be heated efficiently.

In a preferred embodiment of the piezoelectric oscillator of the present invention, the resistance pattern of the heater substrate and the wiring pattern of the insulating substrate are electrically connected by bonding wires.

According to this embodiment, the heater substrate mounted on the piezoelectric vibrator mounted on the integrated circuit element on the insulating substrate can be easily connected to the wiring pattern of the insulating substrate by wire bonding. ..

In another embodiment of the piezoelectric oscillator of the present invention, a passive component is mounted on the insulating substrate, and the passive component is housed in the container together with the insulating substrate and airtightly sealed.

According to this embodiment, the integrated circuit element and the crystal oscillator are laminated and mounted on the insulating base 13 plate to secure the mounting space for the passive component on the insulating substrate and mount the passive component. In addition to being mounted, the integrated circuit element, the crystal oscillator, and the passive component mounted on the insulating substrate can be housed in the same container and hermetically sealed. As a result, the influence of an external temperature change or the like can be suppressed, and even if the external temperature or the like changes, the characteristic fluctuation of the piezoelectric oscillator can be suppressed and the oscillation frequency can be stabilized.

In one embodiment of the piezoelectric vibrator of the present invention, the piezoelectric vibrator covers and seals a piezoelectric vibrating plate having excitation electrodes formed on both main surfaces and an exciting electrode on one main surface of the piezoelectric vibrating plate. A first sealing member and a second sealing member that covers and seals the excitation electrode on the other main surface of the piezoelectric vibrating plate are provided, and the piezoelectric vibrating plate has metal for joining on both main surfaces. Each having a film, the first sealing member has a bonding metal film corresponding to the bonding metal film on the one main surface of the piezoelectric vibrating plate, and the second sealing member has the bonding metal film. It has a bonding metal film corresponding to the bonding metal film on the other main surface of the piezoelectric vibrating plate, and the first sealing member and the piezoelectric vibrating plate are bonded by the bonding metal film, and the above. The second sealing member and the piezoelectric vibrating plate are joined by the metal film for joining, and the vibrating portion including the exciting electrodes on both main surfaces of the piezoelectric vibrating plate is the first sealing member and the said. It is hermetically sealed by the second sealing member.

According to this embodiment, the vibrating portion of the piezoelectric vibrator is doubly airtightly sealed by airtightly sealing the piezoelectric vibrator whose vibrating portion is hermetically sealed in the container. As a result, the influence of external temperature changes on the vibrating part of the piezoelectric vibrator can be effectively suppressed, and even if the external temperature changes, the characteristic fluctuation of the piezoelectric oscillator is suppressed and the oscillation frequency is stabilized. Can be achieved.

Further, the piezoelectric vibrator includes a piezoelectric diaphragm in which excitation electrodes are formed on both main surfaces, a first sealing member that covers and seals the excitation electrodes on one main surface, and an excitation electrode on the other main surface. The second sealing member that covers and seals is laminated by joining the metal films for joining 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 storage recess and is bonded to an electrode in the container and airtightly sealed by a conductive adhesive. No. This eliminates the influence of the gas generated from the conductive adhesive and stabilizes the frequency characteristics.

Further, since the piezoelectric vibrator has a three-layer laminated structure of the piezoelectric diaphragm and the first and second sealing members, it is possible to reduce the thickness (lower height) as compared with the above package structure.

In another embodiment of the piezoelectric oscillator of the present invention, the container includes a container body made of ceramic having a storage recess and a lid that covers and airtightly seals the storage recess.

According to this embodiment, even if the flatness of the bottom surface of the accommodating recess of the container body made of ceramic is poor, an insulating substrate having good flatness is mounted on the bottom surface of the accommodating recess, and the wiring of the insulating substrate is mounted. Since the electrode pads of the integrated circuit element are flip-chip connected to the pattern, the load applied at the time of connection is suppressed from being dispersed among the plurality of electrode pads, and stable connection is possible.

In still another embodiment of the piezoelectric oscillator of the present invention, the wiring pattern of the insulating substrate housed in the housing recess and the connection electrode formed on the inner surface of the container body are electrically bonded by a bonding wire. It is connected.

According to this embodiment, the wiring pattern of the insulating substrate on which the integrated circuit element or the like is mounted and the connection electrode connected to the inner surface of the container body are electrically connected by the bonding wire, so that the insulating property is provided. The integrated circuit element or the like mounted on the substrate of the container can be electrically connected to the connection electrode on the inner surface of the container body via a bonding wire, and further, the container can be electrically connected via the internal wiring of the container body or the like. It can be electrically connected to an external connection terminal on the outer bottom surface of the main body, that is, an external connection terminal for mounting the piezoelectric oscillator.

In one embodiment of the piezoelectric oscillator 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, an integrated circuit element having a plurality of electrode pads is flip-chip connected to a wiring pattern formed on an insulating substrate via bumps, but the insulating substrate is compared with ceramics. Since the flatness is good, the load applied at the time of mounting is suppressed from being dispersed among the plurality of electrode pads, stable connection is possible, and the reliability of connection of integrated circuit elements is improved.

FIG. 1 is a schematic configuration diagram of a crystal oscillator according to an embodiment of the present invention. FIG. 2 is a plan view of the base on which the crystal substrate is mounted. FIG. 3 is a plan view of a base on which an IC chip and a capacitor are mounted. FIG. 4 is an enlarged cross-sectional view of the crystal oscillator of FIG. 1 turned upside down and viewed from the side thereof. FIG. 5 is a schematic plan view of both main surfaces of the crystal diaphragm of FIG. FIG. 6 is a schematic plan view of both main surfaces of the first sealing member of FIG. FIG. 7 is a schematic plan view of both sides of the second sealing member of FIG. FIG. 8 is a plan view of the base on which the crystal oscillator is mounted. FIG. 9 is a plan view of the heater substrate mounted on the crystal oscillator. FIG. 10 is a plan view of a base on which a heater substrate is mounted and shows a wire-bonded state. FIG. 11 is a schematic configuration diagram corresponding to FIG. 1 of another embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the present embodiment, the piezoelectric oscillator will be described by applying it to a constant temperature bath type crystal oscillator that outputs a highly stable frequency without being affected by an external temperature change.

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

The crystal oscillator 1 of this embodiment includes a crystal substrate 4 as an insulating substrate on which a wiring pattern is formed, an IC chip 3 as an integrated circuit element mounted on the crystal substrate 4 with a flip chip, and a crystal substrate 4. A capacitor 7 which is a passive component mounted on the top, a crystal oscillator 2 mounted on the IC chip 3, and a heater mounted on the crystal oscillator 2 as a heating element to heat the crystal oscillator 2. A substrate 5 and a container 6 for hermetically sealing them are provided. As will be described later, the crystal oscillator 2 includes a crystal vibrating plate 14 and first and second sealing members 15 and 16 that airtightly seal the vibrating portion of the crystal vibrating plate 14.

In this embodiment, the IC chip 3, the crystal oscillator 2, and the heater substrate 5 have substantially the same planar size, and are laminated and mounted on the crystal substrate 4 as shown in FIG.

The upper part of the container 6 is open and is joined to the base 8 via a seal ring 9 and a base 8 as a container main body having a storage recess 8a for accommodating a crystal substrate 4 on which a crystal oscillator 2 and the like are mounted. The lid 10 is provided as a lid that closes the opening of the housing and airtightly seals the accommodating recess 8a.

The base 8 includes a flat bottom plate portion 8b, a first side wall portion 8c formed on the outer periphery thereof, and a second side wall portion 8d formed on the outer periphery of the first side wall portion 8c. A housing recess 8a having a step portion is formed on the inner peripheral wall.

The airtight sealing is performed in a vacuum atmosphere or an inert gas atmosphere such as nitrogen gas, and the space inside the container 6 is a vacuum or an inert gas atmosphere.

The base 8 is made of a ceramic material such as alumina, and is formed by, for example, laminating three ceramic green sheets and integrally firing them in a concave shape having a stepped portion with an open upper portion.

The crystal substrate 4 on which the crystal oscillator 2 and the like are mounted has a wiring pattern formed on the upper surface thereof, and the lower surface thereof is die-bonded to the inner bottom surface of the base 8 via an adhesive.

FIG. 2 is a plan view of the crystal substrate 4 die-bonded to the inner bottom surface of the base 8. A plurality of wiring patterns 11 are formed on the upper surface of the crystal substrate 4.

The flatness of the flat surface of the crystal substrate 4 is better than that of a flat plate made of ceramic, for example, a ceramic substrate or a bottom plate portion of a ceramic package.

Therefore, even if the inner bottom surface of the base 8 made of ceramic is warped, the flatness of the upper surface of the crystal substrate 4 die-bonded to the inner bottom surface of the base 8 via an adhesive is good.

The IC chip 3 includes a plurality of electrode pads, for example, 10 or more, and is connected to the wiring pattern 11 on the upper surface of the crystal substrate 4 via a metal bump 13 as shown in FIG. Will be done.

Since the crystal substrate 4 has a good flatness as described above, the load applied when the IC chip 3 is flip-chip mounted is suppressed from being dispersed among the plurality of electrode pads of the IC chip 3. Stable connection is possible.

A plurality of connection electrodes 12 composed of a conductor wiring pattern are formed on the upper surface of the first side wall portion 8c of the base 8, that is, the upper surface of the step portion of the inner peripheral wall. The connection electrode 12 is electrically connected to the wiring pattern 11 of the crystal substrate 4 by a bonding wire 39 as described later.

FIG. 3 is a plan view corresponding to FIG. 2 showing an IC chip 3 in which a flip chip is mounted on an upper surface of a crystal substrate 4 joined to an inner bottom surface of a base 8. A plurality of capacitors 7 are also mounted on the wiring pattern 11 on the upper surface of the crystal substrate 4 by a bonding material such as solder.

The IC chip 3 has a rectangular shape in a plan view, and incorporates an oscillation circuit, a temperature sensor, and a temperature control circuit that controls heat generation of the heater substrate 5 based on the detected temperature of the temperature sensor.

The crystal oscillator 2 is mounted on the IC chip 3 as shown in FIG. The crystal oscillator 2 is mounted in an inverted state so that the external connection terminal described later faces upward.

FIG. 4 is an enlarged cross-sectional view of the crystal oscillator 2 of FIG. 1 viewed from the side, and is an enlarged cross-sectional view of the crystal oscillator 2 of FIG. 1 inverted upside down. The crystal oscillator 2 includes a crystal diaphragm 14 which is a piezoelectric diaphragm, a first sealing member 15 which covers and airtightly seals one main surface side of the crystal diaphragm 14, and the other of the crystal diaphragm 14. It is provided with a second sealing member 16 that covers the main surface side and seals airtightly.

In the crystal oscillator 2, the first and second sealing members 15 and 16 are joined to both main surfaces of the crystal diaphragm 14, respectively, to form a package having a so-called sandwich structure. The package of the crystal oscillator 2 is a rectangular parallelepiped and has a rectangular shape in a plan view.

Next, each configuration of the crystal diaphragm 14 and the first and second sealing members 15 and 16 constituting the crystal oscillator 2 will be described.

5 (a) is a schematic plan view showing one main surface (upper surface in FIG. 4) side of the crystal diaphragm 14 of FIG. 4, and FIG. 5 (b) is from one main surface side of the crystal diaphragm 14. It is a schematic plan view which shows the other main surface (lower surface in FIG. 4) side which was seen through.

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

The crystal diaphragm 14 connects a substantially rectangular vibrating portion 20, an outer frame portion 22 that surrounds the vibrating portion 20 with a space (gap) 21 interposed therebetween, and the vibrating portion 20 and the outer frame portion 22. It is provided with a unit 23. The vibrating portion 20, the outer frame portion 22, and the connecting portion 23 are integrally formed. Although not shown, the vibrating portion 20 and the connecting portion 23 are formed thinner than the outer frame portion 22.

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

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

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

The first and second excitation electrodes 24 and 25 of the crystal diaphragm 14, the first and second extraction electrodes 26 and 27, the first and second sealing bonding patterns 31 and 32, and the connecting bonding patterns 28 and 30. Is configured by, for example, Au being laminated and formed on a base layer made of, for example, Ti or Cr.

6 (a) is a schematic plan view showing one main surface (upper surface in FIG. 4) side of the first sealing member 15 of FIG. 4, and FIG. 6 (b) is one of the first sealing members 15. It is a schematic plan view which shows the other main surface (lower surface in FIG. 4) side seen through from the main surface side.

The first sealing member 15 is a rectangular parallelepiped substrate made of an AT-cut quartz plate similar to the quartz diaphragm 14. As shown in FIG. 6A, a wiring pattern 48 for heat conduction is formed on one main surface of the first sealing member 15 on the entire surface except for the outer peripheral edge. As shown in FIG. 6B, the other main surface of the first sealing member 15 is bonded to and sealed to the first sealing bonding pattern 31 on one main surface of the crystal diaphragm 14. The first sealing bonding pattern 33 as the bonding metal film is formed in an annular shape over the entire circumference of the first sealing member 15 so as to substantially follow the outer peripheral edge of the first sealing member 15. ..

The first sealing member 15 is formed with a through electrode 49 that penetrates between both main surfaces and connects the wiring pattern 48 on one main surface and the first sealing bonding pattern 33 on the other main surface. ing. The through electrode 49 is configured such that a metal film is adhered to the inner wall surface of the through hole.

The wiring pattern 48 and the first sealing bonding pattern 33 are configured by, for example, au being laminated on a base layer made of, for example, Ti or Cr.

7 (a) is a schematic plan view showing one main surface (upper surface in FIG. 4) side of the second sealing member 16 of FIG. 4, and FIG. 7 (b) is one of the second sealing members 16. It is a schematic plan view which shows the other main surface (lower surface in FIG. 4) side seen through from the main surface side.

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

As shown in FIG. 7A, one main surface of the second sealing member 16 is bonded to and sealed to the second sealing bonding pattern 32 on the other main surface of the quartz diaphragm 14. The second sealing bonding pattern 34 as the bonding metal film is formed in an annular shape over the entire circumference of the second sealing member 16 so as to substantially follow the outer peripheral edge 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 the two main surfaces are formed inside the annular second sealing bonding pattern 34. Each of the through electrodes 42 and 43 is configured such that a metal film is adhered to the inner wall surface of the through hole.

On one short side of the inside of the annular second sealing joint pattern 34 of the second sealing member 16, the connecting joint pattern 37 is provided on 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 later, the first through electrode 29 is joined to the connecting bonding pattern 37 and electrically connected. As shown in FIG. 5A, the first through electrode 29 is electrically connected to the first excitation electrode 24 of the crystal diaphragm 14. Therefore, the connection pattern 37 on one main surface of the second sealing member 16 is electrically connected to the first excitation electrode 24 by joining the crystal diaphragm 14 and the second sealing member 16.

As shown in FIG. 7A, the connection pattern 37 is electrically connected to the second through electrode 42 near the other short side via the connection wiring pattern 36. Therefore, the second through electrode 42 has a connection wiring pattern 36, a connection connection pattern 37, a first through electrode 29 of the crystal diaphragm 14, and a connection by joining the crystal diaphragm 14 and the second sealing member 16. 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 so as to correspond to the connection pattern 30 on the other main surface of the quartz diaphragm 14. The connection 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. 5 (b). Therefore, by joining the crystal diaphragm 14 and the second sealing member 16 as described later, the third through electrode 43 of the second sealing member 16 has a joining pattern 30 for connecting the crystal diaphragm 14. It is electrically connected to the second excitation electrode 25 via the second extraction electrode 27.

As shown in FIG. 7B, a pair of first and second external connection terminals 40 and 41 for electrically connecting 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 on both end sides 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. Since 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 as described above, the first and second external connection terminals are connected. 40 and 41 are electrically connected to the first and second excitation electrodes 24 and 25, respectively.

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

In the crystal oscillator 2 of this embodiment, the crystal diaphragm 14 and the first sealing member 15 are diffusion-bonded in a state where the first sealing bonding patterns 31 and 33 are overlapped with each other, and the crystal vibration is formed. The plate 14 and the second sealing member 16 are diffusion-bonded in a state where the second sealing bonding patterns 32 and 34 are overlapped with each other to manufacture a package having a sandwich structure shown in FIG. As a result, the accommodation space in which the vibrating portion 20 of the crystal diaphragm 14 is accommodated is hermetically sealed by both sealing members 15 and 16.

In this way, the crystal diaphragm 14 and the three crystal plates of the first and second sealing members 15 and 16 are laminated to obtain a crystal oscillator 2 having a package structure in which the vibrating portion 20 is housed. As a result, the crystal unit is thinner (lowered in height) than a crystal oscillator with a package structure in which a crystal vibrating piece is housed in a box-shaped ceramic container having a recess that serves as a storage space, and a lid is joined and sealed. Can be planned.

The crystal oscillator 2 shown in FIG. 4 is turned upside down so that the first sealing member 15 is on the lower surface and the second sealing member 16 is on the upper surface, so that the crystal oscillator 2 is placed on the upper surface, which is the inactive surface of the IC chip 3. It is joined via an adhesive.

FIG. 8 is a plan view of the base 8 showing the crystal oscillator 2 joined to the upper surface of the IC chip 3 shown in FIG. The first and second external connection terminals 40 and 41 of the crystal oscillator 2 mounted on the IC chip 3 are exposed upward.

FIG. 9 is a plan view showing a heater substrate 5 mounted on the crystal oscillator 2.

In the heater substrate 5, a resistance wiring 18 having a meandering pattern is formed on a substrate 17 such as quartz. The substrate 17 has a first notched portion 17a in which one of the four corner portions having a substantially rectangular shape in a plan view is cut out in a rectangular shape, and a portion closer to the short side of one of the long sides is cut out in a rectangular shape. It also has a second notch portion 17b. These notches 17a and 17b expose a part of the first and second external connection terminals 40 and 41 of the crystal oscillator 2 upward while the heater substrate 5 is mounted on the crystal oscillator 2. Notch for.

Both ends 18a and 18b of the resistance wiring 18 are drawn out to one short side, and for this resistance wiring 59, for example, nichrome, chromium, tungsten or the like is used.

FIG. 10 is a plan view showing a state in which the heater substrate 5 is mounted on the crystal oscillator 2 of FIG. 8 and wire bonding is performed.

In the heater substrate 5, the lower surface side on which the resistance wiring 18 is not formed is joined to the crystal oscillator 2 with an adhesive. In this state, a part of the first and second external connection terminals 40 and 41 of the second sealing member 16 of the crystal oscillator 2 is exposed upward from the first and second notches 17a and 17b of the heater substrate 5. doing.

The first and second external connection terminals 40 and 41 of the crystal oscillator 2 and both ends 18a and 18b of the resistance wiring 18 of the heater substrate 5 are formed by the bonding wire −38 to form the required wiring pattern 11 of the crystal substrate 4. Are electrically connected to each.

As a result, the IC chip 3 flip-chip mounted on the crystal substrate 4 is electrically connected to the crystal oscillator 2 and the heater substrate 5 via the wiring pattern 11 of the crystal substrate 4, respectively.

Further, the required wiring pattern 11 of the crystal substrate 4 is electrically connected to the required connection electrode 12 on the upper surface of the first side wall portion 8c of the base 8 by the bonding wire-39, respectively.

As a result, the IC chip 3 has a power supply terminal, an output terminal, and a control (not shown) on the outer bottom surface of the base 8 via the wiring pattern 11 of the crystal substrate 4, the bonding wire 39, the connection electrode 12 of the base 8, and the internal wiring of the base 8. It is electrically connected to a plurality of external connection terminals such as terminals and GND terminals, that is, a plurality of external connection terminals for mounting the crystal oscillator 1.

As the material of the bonding wires 38 and 39, Au is preferable from the viewpoint of reliability, but Cu or the like may also be used.

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

According to the crystal oscillator 1 of the present embodiment having the above configuration, the accommodating recess 8a of the ceramic base 8 accommodates the crystal substrate 4 having a flatterness better than that of the ceramic substrate or the ceramic package. Since the IC chip 3 is flip-chip mounted on the wiring pattern 11 of the substrate 4, the load applied at the time of mounting is higher than that when the IC chip is flip-chip mounted on the ceramic substrate or the ceramic package. Dispersion between a plurality of electrode pads is suppressed, stable connection is possible, and reliability of connection of the IC chip 3 is improved.

Further, the vibrating portion 20 of the crystal diaphragm 14 is hermetically sealed by the first and second sealing members 15 and 16, and the crystal vibrating plate 2 is hermetically sealed by the container 6, so that the crystal vibrates. The circumference of the vibrating portion 20 of the plate 14 can be configured to be extremely effectively insulated from the outside. As a result, it is possible to reduce the influence of external temperature changes and obtain a stable oscillation frequency.

Further, since the crystal oscillator 2 is mounted on the IC chip 3, the temperature of the crystal oscillator 2 can be accurately detected by the temperature sensor built in the IC chip 3, and the temperature of the crystal oscillator 2 is controlled. Can be performed with high accuracy. In the crystal oscillator 2, one main surface of the first sealing member 15 on which the wiring pattern 48 for heat conduction is formed is bonded to the IC chip 3, so that the heat generated by the IC chip 3 is generated. 1 Conducts to the first sealing joint pattern 31 of the crystal diaphragm 14 via the wiring pattern 48 of the sealing member 15, the through electrode 49, and the first sealing joint pattern 33. As a result, the crystal diaphragm 14 can be efficiently heated by the heat generated by the IC chip 3.

Further, the crystal oscillator 2 includes a crystal vibrating plate 14 in which the first and second excitation electrodes 24 and 25 are formed on both main surfaces, and a first sealing member 15 that covers and seals the first excitation electrode 24. , The second sealing member 16 that covers and seals the second excitation electrode 25 is laminated by joining the metal films for joining to each other, so that the crystal vibrating piece is accommodated in the container having the accommodating recess. It is not necessary to use a conductive adhesive as in the case of a package structure in which the electrodes are joined to the electrodes in the container using a conductive adhesive and the lid is hermetically sealed. As a result, the frequency characteristics are stabilized without being affected by the gas generated from the conductive adhesive.

FIG. 11 is a schematic configuration diagram corresponding to FIG. 1 of another embodiment of the present invention.

In the above embodiment, the crystal oscillator 2 and the heater substrate 5 are laminated and mounted on the IC chip 3 on which the flip chip is mounted on the crystal substrate 4, but in the crystal oscillator 1 ₁ of this embodiment, the crystal substrate 4 _{1 is mounted.} The crystal oscillator 2 and the heater substrate 5 are not mounted on the IC chip 3 mounted on the flip chip, but the crystal oscillator 2 is mounted on _{the crystal substrate 4 1 and the heater is mounted on the crystal oscillator 2.} The substrate 5 is mounted.

The quartz substrate 4 _1, passive components such as capacitors (not shown) is mounted.

Other configurations are the same as those of the embodiment shown in FIG.

In each of the above embodiments, the first and second notches 17a and 17b are formed in the heater substrate 5 to expose a part of the first and second external connection terminals 40 and 41 of the crystal oscillator 2. The plane size of the heater substrate 5 may be reduced to expose a part of the first and second external connection terminals 40 and 41 without forming a notch in the heater substrate 5. Alternatively, the plane size of the crystal oscillator 2 may be made larger than that of the heater substrate 5 to expose the first and second external connection terminals 40 and 41.

In each of the above embodiments, a quartz substrate is used as the insulating substrate having good flatness, but the present invention is not limited to the quartz substrate, and a glass substrate or the like may be used.

As the heating element for heating the crystal oscillator 2, for example, a film resistor having a resistance pattern of a metal foil formed on a polyimide film or the like may be used instead of the heater substrate 5, and the chip resistor is used on the crystal substrate 4. It may be installed.

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

In each of the above embodiments, 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 the AT-cut crystal may be used.

In the above embodiment, the through electrodes 29, 42, and 43 are configured such that a metal film is adhered to the inner wall surface of the through holes, but the present invention is not limited to this, and the through holes may be filled with a conductive material.

1,1 ₁ Crystal oscillator 2 Crystal oscillator 3 IC chip (integrated circuit element)
4,4 ₁ Crystal substrate (insulating substrate)
5 Heater board 6 Container 7 Capacitor (passive component)
8 base (container body)
10 lid (lid)
11 Wiring pattern 12 Connection electrode 13 Metal bump 14 Crystal diaphragm 15 1st sealing member 16 2nd sealing member 38, 39 Bonding wire

Claims (10)

An insulating substrate that has better flatness than ceramic and has a wiring pattern formed on it.
Piezoelectric oscillator and
The integrated circuit element mounted on the insulating substrate and
A heating element that heats the piezoelectric vibrator and
A container for accommodating and airtightly sealing the insulating substrate on which the integrated circuit element is mounted is provided.
The integrated circuit element has a plurality of electrode pads, and the electrode pads are flip-chip-connected to the wiring pattern of the insulating substrate via bumps.
A piezoelectric oscillator characterized by that. The insulating substrate is a crystal substrate or a glass substrate.
The piezoelectric oscillator according to claim 1. The piezoelectric vibrator is mounted on the integrated circuit element mounted on the insulating substrate, and is housed in the container together with the insulating substrate and airtightly sealed.
The piezoelectric oscillator according to claim 1 or 2. The heating element is a heater substrate mounted on the piezoelectric vibrator mounted on the integrated circuit element, and the heater substrate is housed in the container together with the insulating substrate and airtightly sealed.
The piezoelectric oscillator according to claim 3. The resistance pattern of the heater substrate and the wiring pattern of the insulating substrate are electrically connected by bonding wires.
The piezoelectric oscillator according to claim 4. A passive component is mounted on the insulating substrate, and the passive component is housed in the container together with the insulating substrate and airtightly sealed.
The piezoelectric oscillator according to any one of claims 3 to 5. The piezoelectric vibrator includes a piezoelectric vibrating plate in which excitation electrodes are formed on both main surfaces, a first sealing member that covers and seals the exciting electrodes on one main surface of the piezoelectric vibrating plate, and the piezoelectric vibration. It is provided with a second sealing member that covers and seals the excitation electrode on the other main surface of the plate.
The piezoelectric diaphragm has metal films for joining on both main surfaces thereof, and the first sealing member is for joining corresponding to the metal film for joining on one main surface of the piezoelectric diaphragm. The second sealing member has a metal film for joining, and the second sealing member has a metal film for joining corresponding to the metal film for joining on the other main surface of the piezoelectric diaphragm.
The first sealing member and the piezoelectric diaphragm are joined by the metal film for joining, and the second sealing member and the piezoelectric diaphragm are joined by the metal film for joining, and the piezoelectric diaphragm is joined. The vibrating portion including the excitation electrodes on both main surfaces of the above is hermetically sealed by the first sealing member and the second sealing member.
The piezoelectric oscillator according to any one of claims 1 to 6. The container includes a container body made of ceramic having a storage recess and a lid body that covers and airtightly seals the storage recess.
The piezoelectric oscillator according to any one of claims 1 to 7. The wiring pattern of the insulating substrate housed in the storage recess and the connection electrode formed on the inner surface of the container body are electrically connected by a bonding wire.
The piezoelectric oscillator according to claim 8. Equipped with a temperature sensor
The integrated circuit element controls the heat generation of the heating element based on the temperature detected by the temperature sensor.
The piezoelectric oscillator according to any one of claims 1 to 9.

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