Piezoelectric oscillator

Abstract

The present invention provides a piezoelectric oscillator that can ensure sufficient holding strength of the piezoelectric diaphragm even when the piezoelectric diaphragm is miniaturized. [Solution] The piezoelectric oscillator 1 comprises a piezoelectric diaphragm 2 having a first main surface 20a and a second main surface 20b as the back surface of the first main surface 20a, an IC 5 including a temperature sensor, and a package 3 having a housing section 31 that houses the piezoelectric diaphragm 2 and the IC 5 in the same space. The piezoelectric diaphragm 2 has a vibrating section 25 and a holding section 26 held by the package 3. The package 3 has a stepped section 32 that protrudes from the side wall of the housing section 31 toward the inside of the housing section 31 and has a first mounting pad 6a and a second mounting pad 6b on its upper surface for mounting and holding the piezoelectric diaphragm 2, and an IC housing section 31a provided as part of the housing section 31 for housing the IC 5. The holding section 26 is provided on the same straight line extending in a first direction and protrudes in the first direction when viewed from the vibrating section 25.

Description

Technical Field

[0001] The present invention relates to a piezoelectric oscillator including a piezoelectric diaphragm and an IC.

Background Art

[0002] Conventionally, a piezoelectric oscillator in which a ceramic package houses a piezoelectric diaphragm and an IC incorporating an oscillation circuit has been used.

[0003] As such a piezoelectric oscillator, an oscillator having a configuration (single package configuration) in which a vibrating piece (piezoelectric diaphragm) and an IC are arranged and housed in the same space has been disclosed (see Patent Document 1).

[0004] Among piezoelectric oscillators, in particular, a temperature-compensated crystal oscillator (TCXO) in which the piezoelectric diaphragm is made of crystal, the IC incorporates a temperature sensor and a temperature compensation circuit, and the oscillation frequency is corrected based on temperature information acquired by the temperature sensor is widely used.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In recent years, piezoelectric vibration devices have become smaller, and consequently, the piezoelectric diaphragms mounted inside them have also become smaller. Furthermore, when the piezoelectric diaphragm is made of quartz, it is possible to form many piezoelectric diaphragms on a single quartz wafer. The smaller the individual piezoelectric diaphragm, the more can be obtained from a single quartz wafer, thus reducing manufacturing costs. There is a demand to share these miniaturized piezoelectric diaphragms across various products. However, in the case of piezoelectric oscillators that incorporate ICs, such as those described in Patent Document 1, space is required to mount the ICs, limiting the miniaturization of the package. Moreover, even if the size of the piezoelectric diaphragm is reduced, the package size and internal configuration do not change, so the holding area for the piezoelectric diaphragm also becomes smaller, making it difficult to ensure sufficient holding strength for the piezoelectric vibrator. Consequently, the piezoelectric diaphragm may not be held securely, and there is a risk that it may fall into the space (cavity) where the IC is mounted due to external shocks, etc.

[0007] The present invention has been made in view of the above problems, and aims to provide a piezoelectric oscillator that can ensure sufficient holding strength of the piezoelectric diaphragm even when the piezoelectric diaphragm is miniaturized. [Means for solving the problem]

[0008] The present invention comprises a piezoelectric diaphragm having a first main surface and a second main surface as the back surface of the first main surface, an IC including a temperature sensor, and a package having a housing section for housing the piezoelectric diaphragm and the IC in the same space, wherein the piezoelectric diaphragm has a vibrating section having a first excitation electrode provided on the first main surface and a second excitation electrode provided on the second main surface, and two holding sections held by the package, wherein the package has a stepped section having two piezoelectric diaphragm mounting pads that project outward from the inner surface of the housing section toward the housing section and on the upper surface thereof on which the piezoelectric diaphragm is mounted, and an IC housing section provided as part of the housing section for housing the IC, wherein the two holding sections of the piezoelectric diaphragm are provided on the same straight line extending in a first direction and project outward in opposite directions along the first direction, and are characterized as a piezoelectric oscillator.

[0009] In other words, the piezoelectric oscillator of the present invention has a configuration in which the two holding portions of the piezoelectric diaphragm are provided on the same straight line extending in a first direction and protruding in the first direction. With this configuration, if the size of the piezoelectric diaphragm is reduced compared to a conventional configuration, the holding area would normally also be reduced, making it difficult to ensure the holding strength of the piezoelectric vibrator. However, with the configuration of the present invention, the piezoelectric diaphragm can be held in the piezoelectric diaphragm mounting portion over a large area, thus ensuring sufficient holding strength of the piezoelectric diaphragm. That is, even when the piezoelectric diaphragm is miniaturized, a relatively wide holding area can be secured, thus ensuring sufficient holding strength of the piezoelectric diaphragm.

[0010] Furthermore, the stepped portion may have a notch cut out from the IC housing side between the two piezoelectric diaphragm mounting pads in a plan view. With such a configuration, an instrument (shear tool) used to inspect the mounting state of the IC can be inserted into the notch (recess). However, if the stepped portion has such a notch, the area for holding the piezoelectric diaphragm becomes smaller, and there is a risk that sufficient holding strength cannot be ensured. With the configuration of the present invention, the piezoelectric diaphragm can be held in the piezoelectric diaphragm mounting portion over a large area, so sufficient holding strength for the piezoelectric diaphragm can be ensured.

[0011] Furthermore, the IC mounted in the package may be configured to overlap at least 80% of the first and second excitation electrodes of the piezoelectric diaphragm mounted in the package, in a plan view. With such a configuration, the difference between the temperature detected by the temperature sensor built into the IC and the temperature of the excitation electrodes, which are essential for the vibration characteristics of the piezoelectric diaphragm, can be reduced.

[0012] Furthermore, the piezoelectric diaphragm may be held in the package only near one end where the two holding parts are located, and the entire end of the piezoelectric diaphragm opposite to the end where the holding parts are located may overlap with the IC in a plan view. With such a configuration, even if the free end of the piezoelectric diaphragm bends with the holding part as a fulcrum due to an external shock, it is possible to prevent the piezoelectric diaphragm from coming into contact with the edge of the IC and being damaged. In other words, the shock resistance of the piezoelectric oscillator can be improved. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a piezoelectric oscillator that can ensure sufficient holding strength of the piezoelectric diaphragm even when the piezoelectric diaphragm is miniaturized. [Brief explanation of the drawing]

[0014] [Figure 1] A top view of a piezoelectric oscillator according to the first embodiment. [Figure 2] Schematic internal side view of a piezoelectric oscillator in a state where it is hermetically sealed with a lid, as shown in Figure 1. [Figure 3] A top view of the package in the state without the piezoelectric diaphragm according to the first embodiment. [Figure 4] A top view of a piezoelectric diaphragm according to the first embodiment. [Figure 5] Cross-sectional view AA of the piezoelectric diaphragm in Figure 4. [Figure 6] A top view of a piezoelectric diaphragm according to the second embodiment. [Figure 7] A top view of a piezoelectric diaphragm according to the third embodiment.

Best Mode for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0016] <First Embodiment> FIG. 1 is a top view of a piezoelectric oscillator 1 according to the first embodiment, FIG. 2 is a schematic inner side view of the piezoelectric oscillator 1 in a hermetically sealed state with a lid 4 in FIG. 1, FIG. 3 is a top view of a package 3 in a state where a piezoelectric vibrating plate 2 according to the first embodiment is not mounted, FIG. 4 is a top view of the piezoelectric vibrating plate 2 according to the first embodiment, and FIG. 5 is a cross-sectional view taken along line A-A of the piezoelectric vibrating plate 2 in FIG. 4.

[0017] The piezoelectric oscillator 1 includes a package 3 having a housing portion 31, a piezoelectric vibrating plate 2 and an IC 5 housed in the housing portion 31, and a lid 4 joined to the upper surface of the package 3 to hermetically seal the housing portion 31. That is, in the piezoelectric oscillator 1, the piezoelectric vibrating plate 2 and the IC 5 are housed in the same space (housing portion 31).

[0018] The package 3 is a box-shaped body made of an insulating material mainly composed of ceramics such as alumina. For example, it is formed by a lower layer portion 3a, a middle layer portion 3b, and an upper layer portion 3c which are formed by laminating three ceramic green sheets and integrally firing them. In the present embodiment, a rectangular frame-shaped middle layer portion 3b is laminated on the lower layer portion 3a which is disposed at the bottommost among the lower layer portion 3a, the middle layer portion 3b, and the upper layer portion 3c, and a further rectangular frame-shaped upper layer portion 3c is laminated on the middle layer portion 3b. Therefore, the package 3 has a rectangular housing portion 31 in a plan view with the upper surface of the lower layer portion 3a as the bottom surface and the middle layer portion 3b and the upper layer portion 3c as a frame-shaped dike portion 30. Further, the middle layer portion 3b protrudes toward the housing portion 31, and a part of it constitutes a stepped portion 32 on which the piezoelectric vibrating plate 2 is mounted. That is, the stepped portion 32 is formed to protrude from the inner side surface of the housing portion 31 toward the housing portion 31.

[0019] In addition, the package 3 has external terminals 8 made of a metal film on the bottom surface (the main surface on the side where the dike portion 30 of the lower layer portion 3a is not provided). In the present embodiment, four external terminals 8 are provided at each corner on the bottom surface of the package 3 having a substantially rectangular shape, that is, a total of four. That is, in addition to the two external terminals 8 shown in the figure, two external terminals not shown are provided. Note that the number of external terminals 8 provided on the bottom surface of the package 3 is not particularly limited, and can be an appropriate number according to the size of the package 3, the number of terminals of the external substrate on which the piezoelectric oscillator 1 is mounted, or the use of the piezoelectric oscillator 1, etc.

[0020] Furthermore, the package 3 has an IC mounting pad 34 for mounting the IC 5 on the bottom surface of the accommodating portion 31 (the upper surface of the lower layer portion 3a). The IC mounting pad 34 is conductively joined to the corresponding external mounting terminals (not shown) provided on the IC 5 via a bonding material 51. Therefore, the package 3 has an IC accommodating portion 31a formed by the bottom surface (the upper surface of the lower layer portion 3a) and the inner surface of the middle layer portion 3b as a part of the accommodating portion 31. The IC mounting pad 34 can be formed, for example, by laminating nickel and gold in this order on the upper surface of a tungsten metallized layer using a technique such as plating. Note that molybdenum may be used instead of tungsten as the metallized layer. The bonding material 51 can be, for example, a metal bump of gold. In such a case, the IC 5 can be mounted on the package 3 by bump bonding. Note that the number of IC mounting pads 34 provided on the bottom surface of the accommodating portion 31 is not particularly limited, and can be an appropriate number according to the number of external mounting terminals of the IC 5 to be mounted.

[0021] In the present embodiment, the package 3 is configured to be formed of ceramic, but is not limited to this configuration. For example, the package 3 may be formed of quartz or glass.

[0022] The stepped portion 32 has an edge 33 as an end face that protrudes from the housing portion 31 in a plan view. The stepped portion 32 also has a notch 35 cut out from the housing portion 31 near the center of the edge 33. The notch 35 has an opening that communicates with the edge 33 and the upper surface, and is open to the housing portion 31 and IC housing portion 31a on the upper side. Furthermore, the opening on the edge 33 side extends to the bottom surface of the housing portion 31 (IC housing portion 31a). Therefore, the bottom surface of the housing portion 31 (IC housing portion 31a) is visible in a plan view through the notch 35. With a configuration including a notch 35 as in this embodiment, a shear tool for checking the bonding strength of the IC 5 to the package 3 can be inserted.

[0023] Furthermore, the stepped portion 32 is provided with a first mounting pad 6a and a second mounting pad 6b on its upper surface, which are electrically bonded to the piezoelectric diaphragm 2. The first mounting pad 6a and the second mounting pad 6b are formed in parallel in a first direction with a gap between them, and a notch 35 is positioned between them. The first mounting pad 6a and the second mounting pad 6b are connected to the first lead electrode 22a and the second lead electrode 22b of the piezoelectric diaphragm 2 by bonding materials 7a and 7b, respectively. In this embodiment, the first mounting pad 6a and the first lead electrode 22a are electrically bonded by bonding material 7a, and the second mounting pad 6b and the second lead electrode 22b are electrically bonded by bonding material 7b. That is, the first mounting pad 6a and the second mounting pad 6b correspond to the piezoelectric diaphragm mounting pads in the present invention. The first mounting pad 6a and the second mounting pad 6b are opposite in polarity to each other and are electrically connected to a plurality of external terminals 8 provided on the outer bottom surface of the package 3 via internal wiring and vias (not shown).

[0024] In this embodiment, the first mounted pad 6a, the second mounted pad 6b, and each external terminal can be formed, for example, by laminating nickel and gold in that order on the upper surface of a tungsten metallized layer using a method such as plating. Molybdenum may be used instead of tungsten as the metallized layer. Furthermore, conductive adhesives can be used as the bonding materials 7a and 7b, for example.

[0025] The lid 4 can be, for example, a rectangular metal lid in plan view, with Kovar as the base material. Alternatively, the lid 4 can have a configuration in which a metal brazing material is formed around the periphery on the nickel-plated outer periphery of the surface that joins with the package 3. Furthermore, the lid 4 and the package 3 can be joined by brazing or seam welding.

[0026] In this embodiment, the piezoelectric diaphragm 2 consists of a quartz diaphragm 20 formed from an AT-cut quartz plate, and excitation electrodes 21a, 21b and extraction electrodes 22a, 22b formed on the two main surfaces 20a, 20b of the quartz diaphragm 20, respectively.

[0027] The quartz diaphragm 20 is a thin plate having a first main surface 20a and a second main surface 20b which is the back surface of the first main surface 20a. The quartz diaphragm 20 also has protrusions (first and second protrusions 23 and 24) on both sides of the short side, projecting in the first direction (short side direction) from one end in the long side direction (one end on the short side of the outer circumference), giving it an approximate T-shape in appearance. The shape of the quartz diaphragm 20 can be formed, for example, by photolithography. In this embodiment, the quartz diaphragm 20 is made of quartz with an AT cut angle, but it is not limited to this and can take various forms. For example, the quartz diaphragm 20 may be made of quartz with an SC cut angle or Z-plate quartz, or it may be made of a material other than quartz. In this embodiment, the protrusions (first and second protrusions 23 and 24) have a roughly rectangular shape with straight edges, but for example, the edges may be arc-shaped.

[0028] A substantially rectangular first excitation electrode 21a is formed on the portion of the first main surface 20a of the crystal diaphragm 20 that includes the center, and is drawn out along the long side direction and toward one of the short sides of the outer circumference by a wide, strip-shaped first extraction electrode 22a. The first extraction electrode 22a is routed to the second main surface 20b via the side surface at one of the short sides of the outer circumference, and is also formed on at least the first main surface 20a and the second main surface 20b of the first protrusion 23. In this embodiment, the first extraction electrode 22a is formed over the entire area of ​​the first main surface 20a and the second main surface 20b of the first protrusion 23.

[0029] A substantially rectangular second excitation electrode 21b is formed in the portion of the second main surface 20b of the crystal diaphragm 20 that includes the center, and is drawn out along the long side direction and toward one of the short sides of the outer circumference by a wide, strip-shaped second extraction electrode 22b. The second extraction electrode 22b is routed to the first main surface 20a via the side surface at one of the short sides of the outer circumference, and is also formed on at least the first main surface 20a and the second main surface 20b of the second protrusion 24. In this embodiment, the second extraction electrode 22b is formed over the entire area of ​​the first main surface 20a and the second main surface 20b of the second protrusion 24.

[0030] The first excitation electrode 21a, the second excitation electrode 21b, the first extraction electrode 22a, and the second extraction electrode 22b can be formed, for example, by laminating a gold layer on the upper surface of a base metal layer. As the metal forming the base metal film, for example, chromium or titanium can be used. The first excitation electrode 21a, the second excitation electrode 21b, the first extraction electrode 22a, and the second extraction electrode 22b can be formed by sputtering and photolithography.

[0031] In the piezoelectric diaphragm 2, the first excitation electrode 21a and the second excitation electrode 21b are formed to overlap each other in a plan view. The first extraction electrode 22a and the second extraction electrode 22b are formed so as not to overlap each other in a plan view. Furthermore, since the first extraction electrode 22a is formed on the first protrusion 23 and the second extraction electrode 22b is formed on the second protrusion 24, the first extraction electrode 22a and the second extraction electrode 22b are arranged on the same straight line in the first direction (short side direction).

[0032] The piezoelectric diaphragm 2 is electrically connected to the first mounting pad 6a of the package 3 via a bonding material 7a at a first lead electrode 22a formed at one end of the outer short side including the first protrusion 23. Furthermore, the second lead electrode 22b formed at one end of the outer short side including the second protrusion 24 is electrically connected to the second mounting pad 6b of the package 3 via a bonding material 7b. In this configuration, the end of the outer short side including the first protrusion 23 and the second protrusion 24 of the piezoelectric diaphragm 2 forms a holding portion 26. That is, the piezoelectric diaphragm 2 is held by the package 3 at the holding portion 26.

[0033] Furthermore, the piezoelectric diaphragm 2 in this embodiment is a piezoelectric diaphragm in which, when a voltage is applied to the first extraction electrode 22a and the second extraction electrode 22b, the area near the first excitation electrode 21a and the second excitation electrode 21b undergoes thickness-sliding vibration. In other words, the part of the piezoelectric diaphragm 2 closer to the excitation electrode than the holding portion 26 becomes the vibrating portion 25 in this invention.

[0034] IC5 has a temperature sensor and an oscillation circuit that causes the piezoelectric diaphragm 2 to oscillate. In this embodiment, IC5 is an IC chip having a roughly rectangular parallelepiped shape and has external mounting terminals on its bottom surface that correspond to the IC mounting pad 34. IC5 is electrically connected to the IC mounting pad 34 of package 3 via a bonding material 51.

[0035] The piezoelectric oscillator 1 has a configuration in which, when the piezoelectric diaphragm 2 and IC 5 are mounted on the package 3, the piezoelectric diaphragm 2 is held and mounted to the package 3 only near one of the short sides having a holding portion 26 (cantilevered configuration). Furthermore, when the piezoelectric diaphragm 2 and IC 5 are mounted on the package 3, the piezoelectric diaphragm 2 and IC 5 are superimposed on each other. In this case, the piezoelectric diaphragm 2 and IC 5 are arranged with a certain gap in the vertical direction (see Figure 2). It is preferable that the size of this gap is small enough that the piezoelectric diaphragm 2 and IC 5 do not come into contact. Specifically, it is preferable that the size of the gap between the piezoelectric diaphragm 2 and IC 5 is smaller than the thickness of IC 5. That is, when the piezoelectric diaphragm 2 is mounted on an external substrate (not shown), heat from the external substrate is conducted to IC 5 and piezoelectric diaphragm 2 via the package 3, but IC 5, which is closer to the external substrate, will heat up faster than the piezoelectric diaphragm 2. In this case, if the gap between the piezoelectric diaphragm 2 and IC5 is smaller than the thickness of IC5, radiant heat from IC5 can be more easily transferred to the piezoelectric diaphragm 2, bringing the temperature detected by the temperature sensor of IC5 closer to the temperature of the piezoelectric diaphragm 2. However, contact between the piezoelectric diaphragm 2 and IC5 is undesirable because it affects the vibration of the piezoelectric diaphragm 2.

[0036] Furthermore, in the piezoelectric oscillator 1, with the piezoelectric diaphragm 2 and IC 5 mounted on the package 3 (see Figure 1), the entire outer short side of the piezoelectric diaphragm 2 opposite to the outer short side on which the holding portion 26 is provided overlaps with the IC 5 in a plan view. In addition, the size of the IC 5 in a plan view is larger than the size of the first excitation electrode 21a, the second excitation electrode 21b, and the vibrating portion 25 of the piezoelectric diaphragm 2. Preferably, in a plan view, 80% or more of the first excitation electrode 21a and the second excitation electrode 21b of the piezoelectric diaphragm 2 overlap with the IC 5, and more preferably, 90% or more of the first excitation electrode 21a and the second excitation electrode 21b of the piezoelectric diaphragm 2 overlap with the IC 5 in a plan view.

[0037] With the above configuration, it is possible to provide a piezoelectric oscillator that can ensure sufficient holding strength of the piezoelectric diaphragm even when the piezoelectric diaphragm is miniaturized. The piezoelectric oscillator 1 of the present invention has a configuration in which two holding portions 26 of the piezoelectric diaphragm 2 are provided on the same straight line extending in a first direction and protrude in the first direction when viewed from the vibrating portion 25 (having a first protrusion 23 and a second protrusion 24). With this configuration, even if the size of the piezoelectric diaphragm 2 is smaller than in the conventional design, the piezoelectric diaphragm 2 can be held by the first mounting pad 6a and the second mounting pad 6b over a large area, thereby ensuring sufficient holding strength of the piezoelectric diaphragm 2.

[0038] Furthermore, the stepped portion 32 is positioned between the first mounting pad 6a and the second mounting pad 6b and has a notch 35 that opens to the upper housing portion 31 and the IC housing portion 31a. With this configuration, an instrument (shear tool) used to inspect the mounting state of the IC 5 can be received in the notch 35. In addition, if the stepped portion 32 has such a notch 35, the area for holding the piezoelectric diaphragm 2 becomes smaller, and there is a risk that the holding strength of the piezoelectric diaphragm 2 cannot be sufficiently ensured. However, with the configuration of the present invention, the piezoelectric diaphragm 2 can be held by the first mounting pad 6a and the second mounting pad 6b over a large area, so that the holding strength of the piezoelectric diaphragm 2 can be sufficiently ensured.

[0039] Furthermore, the IC5 mounted in package 3 is configured to overlap with at least 80% and 90% of the first excitation electrode 21a and the second excitation electrode 21b of the piezoelectric diaphragm 2 mounted in package 3, in a plan view. With this configuration, the difference between the temperature detected by the temperature sensor built into IC5 and the temperatures of the first excitation electrode 21a and the second excitation electrode 21b, which are essential for the vibration characteristics of the vibrating part 25 of the piezoelectric diaphragm 2, can be reduced.

[0040] Furthermore, the piezoelectric oscillator 1 is configured such that, when the piezoelectric diaphragm 2 and IC 5 are mounted in the package 3, the entire outer short side of the piezoelectric diaphragm 2 opposite to the outer short side on which the holding portion 26 is located overlaps with the IC 5 in a plan view. With this configuration, even if the free end of the piezoelectric diaphragm 2 is deflected with the holding portion 26 as a fulcrum due to an external impact on the piezoelectric oscillator 1, it is possible to prevent the piezoelectric diaphragm from coming into contact with the edge of the IC 5 and being damaged. In other words, the shock resistance of the piezoelectric oscillator 1 can be improved.

[0041] Furthermore, this invention is not limited to the configuration of the embodiments described above, and many other embodiments can be obtained. For example, in this embodiment, the size of the protrusions (first and second protrusions 23 and 24) is such that they protrude by about one-quarter of the length of the other short side of the crystal diaphragm 20. However, the size of the protrusions (first and second protrusions 23 and 24), i.e., the amount of protrusion, is not particularly limited. For example, they may protrude by about half the length of the other short side of the crystal diaphragm 20, or they may protrude to a minute degree. In other words, the protrusions are provided for the purpose of ensuring that the piezoelectric diaphragm 2 has sufficient holding area and holding strength relative to the package 3. The size of the protrusions that can achieve this purpose varies depending on the size of the piezoelectric diaphragm 2, the first mounting pad 6a, and the second mounting pad 6b. Therefore, the size of the protrusions (first and second protrusions 23 and 24), i.e., the amount of protrusion, can be appropriately set depending on the size of the piezoelectric diaphragm 2, the first mounting pad 6a, and the second mounting pad 6b. Furthermore, when forming the outer shape of the quartz diaphragm 20 by photolithography, it is preferable that the size of the protrusions (first and second protrusions 23 and 24) be less than or equal to half the length of the other short side of the quartz diaphragm 20. With such a configuration, in the present invention, which can increase the amount of piezoelectric diaphragms 2 that can be obtained from a single wafer by miniaturizing the piezoelectric diaphragm 2, it is possible to further increase the amount of piezoelectric diaphragms 2 that can be obtained from a single wafer.

[0042] Furthermore, in this embodiment, for example, the piezoelectric diaphragm 2 and IC5 are arranged to overlap in a plan view, but the piezoelectric diaphragm 2 and IC5 may not overlap.

[0043] <Second Embodiment> Figure 6 is a top view of the piezoelectric diaphragm 200 according to the second embodiment. For example, in the first embodiment, the first extraction electrode 22a is formed over the entire area of ​​the first main surface 20a and the second main surface 20b of the first protrusion 23, and the second extraction electrode 22b is formed over the entire area of ​​the first main surface 20a and the second main surface 20b of the second protrusion 24. However, each extraction electrode 202a, 202b may be formed only on a portion of the corresponding protrusions 203, 204 in the second direction. For example, as shown in Figure 6, each extraction electrode 202a, 202b may be formed in an area from one short side to about halfway in the second direction of the corresponding protrusions 203, 204. With such a configuration, when the piezoelectric diaphragm 200a is mounted on the package 3, the bonding materials 700a, 700b will be in contact with the quartz substrate in the corresponding protrusions 203, 204. Furthermore, since the adhesive strength with the bonding material is greater for the quartz substrate than for the gold in each extraction electrode, the holding strength of the piezoelectric diaphragm 2 to the package 3 can be further improved.

[0044] <Third Embodiment> Figure 7 is a top view of the piezoelectric diaphragm 210 according to the third embodiment. Furthermore, for example, the piezoelectric diaphragm 210 may have a configuration in which notches 217 and 218 are provided between the first protrusion 213 and the second protrusion 214 and the vibrating portion 215, respectively. With such a configuration, it is possible to suppress the leakage of vibrations generated in the vibrating portion 215 to the holding portion 216, and the electrical characteristics (CI value) of the piezoelectric diaphragm 210 can be improved.

[0045] The embodiments disclosed herein are illustrative in all respects and are not intended to be restrictive. Therefore, the technical scope of the present invention is not construed solely by the embodiments described above, but is defined by the claims. This includes all modifications within the meaning and scope of the equivalents of the claims. [Industrial applicability]

[0046] The piezoelectric oscillator of the present invention can be used in the manufacturing and sales industry of temperature-compensated crystal oscillators. [Explanation of Symbols]

[0047] 1… Piezoelectric oscillator 2… Piezoelectric diaphragm 20... Circuit board 20a...First main surface 20b…Second main surface 21a...first excitation electrode 21b...Second excitation electrode 22a...First extraction electrode 22b…Second extraction electrode 23...First protrusion 24...Second protrusion 25…Vibrating part 26...Holding part 3…Package 30...Bank part 31... Detention Unit 31a...IC housing section 32...Double part 33...Edge 34…IC-equipped pad 35... Notch 4…Lid 5…IC 6a...First mounted pad 6b...Second mounted pad 7a, 7b…bonding material 8…External terminals

Claims

1. A piezoelectric diaphragm having a first main surface and a second main surface as the back surface of the first main surface, An IC including a temperature sensor, The package comprises a housing section that houses the piezoelectric diaphragm and the IC in the same space, The piezoelectric vibrating plate is A vibrating section having a first excitation electrode provided on the first main surface and a second excitation electrode provided on the second main surface, The package has two holding parts that are held in place, The aforementioned package is A stepped portion having two piezoelectric diaphragm mounting pads on which the piezoelectric diaphragm is mounted, which are provided protruding from the inner surface of the housing portion toward the housing portion, It has an IC housing section provided as part of the housing section for housing the IC, The two holding portions of the piezoelectric diaphragm are arranged on the same straight line extending in the first direction and protrude in opposite directions along the first direction. Piezoelectric oscillator.

2. The stepped portion has a notch cut out from the IC housing side between the two piezoelectric diaphragm mounting pads in a plan view. The piezoelectric oscillator according to claim 1.

3. The IC mounted in the package overlaps, in a plan view, with at least 80% of the first and second excitation electrodes of the piezoelectric diaphragm mounted in the package. A piezoelectric oscillator according to claim 1 or 2.

4. The holding portion of the piezoelectric diaphragm is held in the package only near one end where two such holding portions are provided. The entire end of the piezoelectric diaphragm opposite to the end where the holding portion is provided is superimposed on the IC in a plan view. The piezoelectric oscillator according to claim 3.

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