Crystal Oscillation Device with Temperature Sensor

Abstract

To provide a crystal diaphragm which stabilizes mechanical strengths of a vibration part and a frame body part and improves vibration characteristics of the vibration part, and a crystal vibration device.SOLUTION: A crystal diaphragm 1 consists of an AT cut crystal diaphragm and formed in a rectangular plate shape as a whole. The crystal diaphragm 1 consists of: a vibration part 11; holding parts 13 and 13t connected with the vibration part; and a frame body part 12 disposed in an outer periphery of the vibration part and coupled with the holding part 13. A penetration part 14 is formed circumferentially other than the holding parts 13 and 13t between the vibration part 11 and the frame body part 12. A temperature sensor 4 consisting of a thermistor is surface-joined onto a first holding member by a conductive joint material, and the temperature sensor is covered by a resin material of low thermal conductivity.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a crystal oscillator device with a temperature sensor, in which a temperature sensor is attached to a crystal oscillator device.

Background Art

[0002] In recent years, with the increasing precision of various electronic devices, a temperature-compensated crystal oscillator circuit that compensates for frequency fluctuations due to changes in ambient temperature has been demanded. As a crystal oscillator device corresponding to this, a crystal oscillator with a temperature sensor, in which a temperature sensor such as a thermistor is attached to a crystal resonator, is widely used.

[0003] Such a crystal oscillator with a temperature sensor has a configuration in which a crystal resonator is housed in a ceramic package, and a thermistor is attached to the outside thereof to detect the ambient temperature surrounding the crystal resonator. See Patent Document 1.

[0004] In addition, depending on the application, the above-mentioned electronic devices may be required to be miniaturized and thinned. In such cases, an ultra-miniature or ultra-thin crystal oscillator device is required. For example, in mobile devices, wearable devices, etc., an ultra-miniature or ultra-thin crystal oscillator device is required.

[0005] As a crystal oscillator device corresponding to such a demand, a crystal oscillator device having a three-layer structure in which a crystal oscillator plate is hermetically sealed from above and below with a thin plate sealing member has been proposed. (See Patent Document 2) Note that Patent Document 2 discloses an example in which a thermistor is used as a function part in a crystal resonator having a three-layer structure.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] In Patent Document 1, a ceramic package having a storage portion opened in the vertical direction is used. A crystal oscillator is stored in the upper opening portion, electrically joined to the package, and a thermistor is stored in the lower opening portion and electrically joined to the package.

[0008] In this configuration, since a ceramic package is used and it has two storage portions, there is a problem that miniaturization and thinning are difficult. In Patent Document 2, a thermistor is formed on a crystal oscillator having a three-layer structure. However, referring to the drawing, the joint portion between the crystal oscillator and the thermistor is joined in an extremely small area, and the upper part of the thermistor located on the upper surface of the crystal oscillator is open. Therefore, the transmitted heat is likely to dissipate, and appropriate temperature detection may not be possible. Eventually, the temperature related to the crystal oscillator may not be accurately detected, and appropriate temperature compensation may not be possible. In such a case, the electrical characteristics of this crystal oscillator device become unstable, and as a result, the operation of the electronic device using this may become unstable, which may reduce the reliability of the electronic device.

[0009] The present invention has been made in view of the above problems, and an object thereof is to provide a crystal oscillator device with a temperature sensor that can cope with ultra-miniaturization and ultra-thinning, stably and appropriately detect temperature fluctuations related to the crystal oscillator device, and has excellent electrical characteristics.

Means for Solving the Problems

[0010] The crystal oscillator device with a temperature sensor according to the present invention comprises a crystal oscillator plate, a first sealing member joined to the upper surface of the crystal oscillator plate, a second sealing member joined to the lower surface of the crystal oscillator plate, and a temperature sensor joined to the first sealing member of the crystal oscillator device. The first sealing member and the temperature sensor each have an electrode pad formed thereon, and the two electrode pads are surface-joined by a conductive bonding material. The temperature sensor includes a plate-shaped thermistor element, a pair of electrode pads formed on one main surface of the thermistor element, and a common electrode formed on the other main surface facing the pair of electrode pads. The pair of electrode pads are conductively joined to the electrode pads of the first sealing member, and the temperature sensor joined to the first sealing member is coated with a resin material. The thermal conductivity of the resin material is smaller than that of the conductive bonding material. Ku , one Let the distance between one of the pair of electrode pads formed on one main surface and the common electrode be G2a, and the distance between the other electrode pad of the pair of electrode pads formed on one main surface and the common electrode be G2b. When the distance between one of the pair of electrode pads formed on one main surface Of one of the electrode pads and the pair of electrode pads formed on one main surface Of and the other electrode pad is defined as G1, it is characterized in that G2a + G2b < G1 is satisfied.

[0011] The conductive bonding material may be a resin bonding material added with a conductive filler made of metal powder, metal chips, etc., or a metal brazing material such as solder. These conductive bonding materials surface-join the two electrode pads, and due to the good thermal conductivity of the metal material, the temperature sensor can detect the temperature change of the crystal oscillator device with little time lag.

[0012] And since the temperature sensor is coated with the resin material, the heat transmitted to the temperature sensor will not be dissipated uselessly, so that the temperature in the crystal oscillator device can be accurately detected. As described above, since it is a crystal oscillator device having a three-layer structure including a crystal oscillator plate, a first sealing member, and a second sealing member, the crystal oscillator plate is likely to follow environmental temperature changes. However, due to the good thermal conductivity of the temperature sensor by surface bonding of each electrode pad, temperature information corresponding to the temperature variation of the crystal oscillator plate can be detected.

[0013] Note that the temperature information (such as current value, voltage value, resistance value, etc.) detected by this temperature sensor is connected to the outside through an independent terminal. Then, by an external compensation circuit or the like, the frequency information in the crystal oscillator device can be appropriately temperature-compensated to obtain an accurate frequency.

[0014] A plurality of electrode pads are formed on the joint surface of the temperature sensor with the first sealing member, and the total area of each electrode pad may be 40% to 85% of the area of the temperature sensor. The area mentioned here refers to the projected area, and the area ratio refers to the total projected area of each electrode pad with respect to the projected area of the temperature sensor.

[0015] The larger the contact area of the temperature sensor with the crystal oscillator device, the more accurately the temperature related to the crystal oscillator device can be detected. Therefore, it is better for the electrode pads formed on the temperature sensor to be larger with respect to the area of the temperature sensor. However, if it is too large, short circuits between adjacent electrode pads or short circuits due to the conductive bonding material are likely to occur. When the contact area becomes small, the temperature detection accuracy of the crystal oscillator device decreases. Therefore, when the total area of each electrode pad is 40% to 85% of the area of the temperature sensor, stable temperature detection can be performed.

[0016] The plate-shaped thermistor is manufactured by thick-film forming technologies such as screen printing technology or doctor blade technology, as well as firing technology. A Mn-Fe-Ni-Ti-based material is sintered and formed into a plate-shaped thermistor wafer. An electrode film (metal film) is formed on this plate-shaped thermistor wafer by sputtering, and patterning is performed using photolithography technology. Finally, the thermistor wafer is diced to obtain individual plate-shaped thermistors. Note that the material of the thermistor may be an Mn-Fe-based material or the like.

[0017] The commonly used thermistor (NTC thermistor) has a structure in which a plurality of thermistor materials are laminated through electrode (metal) films by a lamination technology. In the above structure, however, electrode (metal) films are formed on the front and back of a single-layer plate-shaped thermistor material. By forming a pair of electrode pads on one main surface of this plate-shaped thermistor element and forming one electrode pad on the other main surface facing the pair of electrode pads, an extremely thin plate-shaped thermistor can be obtained. These electrode films are formed by a film-forming technology such as PVD like sputtering.

[0018] By adopting a configuration in which such a plate-shaped thermistor is electrically joined to the electrode pads of a crystal vibration device, a crystal vibration device with a temperature sensor corresponding to thinning and miniaturization can be obtained.

[0019] Furthermore, the crystal vibration plate includes a vibration portion formed with a pair of excitation electrodes, a holding portion protruding from at least one location of the vibration portion, and a frame portion surrounding the outer periphery of the vibration portion through a through portion and connected to the holding portion. The first sealing member and the second sealing member may have a plate-shaped configuration, and the crystal vibration plate, the first sealing member, and the second sealing member may be mechanically joined by the frame portion.

[0020] According to the above configuration, a plate-shaped crystal vibrating plate, a first sealing member, and a second sealing member are joined together, forming a thin crystal vibration device configuration. Since a temperature sensor such as a thermistor is joined to this crystal vibration device, a crystal vibration device with a temperature sensor corresponding to thinning and miniaturization can be obtained. The vibrating portion is connected by a holding portion protruding from at least one location, making it less susceptible to external stress. In particular, in order to make it difficult for the external stress caused by the conductive bonding material or resin material generated when joining the thermistor to be transmitted to the vibrating portion, the characteristics of the vibrating portion are stabilized.

[0021] Note that the crystal vibrating plate may be an AT-cut or SC-cut crystal vibrating plate, or may be an X-Y cut crystal vibrating plate or the like.

Effect of the Invention

[0022] According to the present invention, it is possible to obtain a crystal vibration device with a temperature sensor that is compatible with ultra-miniaturization and ultra-thinning, appropriately detects temperature fluctuations related to the crystal vibration device, and has excellent electrical characteristics.

Brief Description of the Drawings

[0023] [Figure 1] It is an exploded perspective view showing each configuration of the crystal vibration device with a temperature sensor according to the present embodiment. [Diagram 2] It is a plan view of one main surface of the crystal vibrating plate. [Diagram 3] It is a plan view of the other main surface (bottom surface) of the second sealing member. [Figure 4] It is a cross-sectional view taken along line A-A when each component in FIG. 1 is assembled. [Diagram 5] It is a plan view of one main surface of the plate-shaped thermistor. [Figure 6] It is a plan view of the other main surface of the plate-shaped thermistor. [Figure 7] It is a cross-sectional view showing another example of the plate-shaped thermistor.

Mode for Carrying Out the Invention

[0024] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0025] First Embodiment The crystal oscillator device Xtl with a temperature sensor according to the first embodiment comprises a crystal oscillator device and a temperature sensor. As shown in FIG. 1, the crystal oscillator device Xtl consists of a crystal oscillator plate 1, a first sealing member 2, and a second sealing member 3, and is configured by laminating the first sealing member 2, the crystal oscillator plate 1, and the second sealing member 3 in this order. Further, the temperature sensor 4 is electrically joined to the upper surface of the crystal oscillator device.

[0026] The crystal oscillator plate 1 is made of an AT-cut crystal oscillator plate and is rectangular plate-shaped as a whole. The crystal oscillator plate 1 comprises a vibrating portion 11, holding portions 13 and 13t connected to two corner portions of the vibrating portion 11, and a frame portion 12 disposed on the outer periphery of the vibrating portion and connected to the holding portions 13 and 13t. A through portion 14 is formed in a circumferential shape between the vibrating portion 11 and the frame portion 12 except for the holding portions 13 and 13t.

[0027] The vibrating portion 11 is rectangular with opposing long sides and short sides and has four corner portions. Note that the vibrating portion may be square when viewed in plan. Rectangular exciting electrodes 111 and 112 are formed on one main surface and the other main surface (front and back main surfaces) at approximately the center of the vibrating portion 11. Strip-shaped lead-out electrodes 111a and 112a are connected to the corner portions of each exciting electrode 111 and 112 and are drawn toward both ends of one side (the corner portion of the vibrating portion). The lead-out electrode 111a is drawn to the frame portion via the holding portion 13, and the lead-out electrode 112a is drawn to the frame portion via the holding portion 13t, and finally is drawn to external connection terminals 31 and 32 formed in the second sealing member 3 described later.

[0028] Specifically, the lead-out electrode 111a passes through the surface of the holding portion 13, is led out to the other main surface through a metal via (through-metal) V1 formed in the frame portion, and is further connected to a metal via V2 formed in the second sealing member 3 described later. The metal via V2 is electrically connected to a terminal electrode 31 formed on the other main surface of the second sealing member 3. Also, the lead-out electrode 112a passes through the back surface of the holding portion 13t, is led out to the other surface of the crystal resonator plate 1, and is electrically connected to a metal via V3 formed in the opposing second sealing member 3. The metal via V3 is electrically connected to a terminal electrode 32 formed on the other main surface of the second sealing member 3.

[0029] These exciting electrodes 111 and 112 and lead-out electrodes 111a and 112a are composed of a plurality of layers of metal films. For example, a Ti film is formed in contact with the crystal resonator plate, and a multi-layer structure with an Au film formed on top thereof. As an example of the thickness of each specific metal film, for example, a Ti film of 5 nm and an Au film of 200 nm can be given, but these can be changed according to the desired characteristics.

[0030] A thick portion 11a is formed on one end side of the vibrating portion 11. The thick portion 11a is at one end side in the X-axis direction and extends in the Z' -axis direction over the entire one end side. The thick portion 11a is formed thicker than the thickness of the vibrating portion 11.

[0031] As shown in FIG. 2, a holding portion 13 is provided at one corner C1 of the vibrating portion 11, and a holding portion 13t is provided at the other corner C2. Each of the holding portions 13 and 13t is connected to the frame portion 12. In the present embodiment, the vibrating portion, the holding portion, and the frame portion are integrally formed from a crystal plate using photolithography technology and wet etching technology. Note that dry etching technology may be used instead of wet etching.

[0032] As shown in FIGS. 1 and 4, the holding portion 13 is configured to be thicker than the vibrating portion 11 and the thick portion 11a, and a taper T2 on an inclined surface is formed from the thick portion 11a to the upper surface of the holding portion 13, and a taper T3 on an inclined surface is formed from the vibrating portion 11 to the holding portion 13. Also, although the holding portion 13 is connected to the frame portion 12, a taper T1 is formed on the upper surface of the frame portion 12 from the holding portion 13. With such a configuration, the respective thicknesses are set in the order of vibrating portion < thick portion < holding portion < frame portion. Note that the thicknesses of the thick portion 11a and the holding portion 13 may be equal. By forming these respective tapers, the boundary region can be rounded. Note that when the step of the boundary region is small or when the risk of disconnection is low, there is no practical problem even if the taper is not formed.

[0033] Specific dimensional examples of the crystal vibrating plate are shown below. The crystal vibrating plate uses a rectangular AT-cut crystal plate, and its outer dimensions are 1.2 mm in width and 1.0 mm in length. The outer dimensions of the vibrating portion are 0.7 mm in width and 0.7 mm in length. The width of the frame portion is 0.2 mm in width and 0.1 mm in length. The dimensions of the holding portion are 0.05 mm in width and 0.15 mm in length. Regarding the thickness of each component portion, the thickness of the frame portion is 0.04 mm, the thickness of the holding portion is 0.03 mm, the thickness of the thick portion is 0.017 mm (17 μm), and the vibrating portion is 0.005 mm (5 μm). Note that it is preferable for the thickness of the thick portion to be 10 or more μm greater than the thickness of the vibrating portion in terms of ensuring mechanical strength.

[0034] Note that in the present embodiment, a configuration is adopted in which thinning is performed only on one main surface of the crystal vibrating plate 1. For example, thinning is performed to a desired frequency (thickness) by an etching technique only from one main surface side. In this case, since etching is not performed on the other main surface side, it is possible to suppress a decrease in vibration characteristics due to roughening of the surface by etching. Note that a configuration in which thinning is performed from both main surfaces may be adopted.

[0035] Sealing films S11 and S21 are formed in a circumferential shape at the front and back outer peripheral ends of the frame portion 12. These sealing films have a multilayer structure in which a Ti film is formed in contact with the crystal vibrating plate and an Au film is formed on the upper portion thereof, similar to the aforementioned electrode film.

[0036] Also, at a position away from the holding portion of the frame body portion 12 and on the inner peripheral side, connection electrodes 121 and 122 are formed. The connection electrodes 121 and 122 are each formed of a strip-shaped metal film formed from the upper surface of the frame body portion through the inner surface to the lower surface of the frame body portion 12. These connection electrodes 121 and 122 are electrically connected to the electrode pads 41 and 42 of the temperature sensor described later, respectively, and are also electrically connected to the terminal electrodes 33 and 34 of the second sealing member.

[0037] The first sealing member 2 is made of a rectangular plate-shaped AT-cut crystal plate and has the same outer shape and outer size as the crystal vibrating plate 2. A circumferential sealing film S12 corresponding to the sealing film S11 is formed on the other main surface (the surface facing the crystal vibrating plate 1) of the first sealing member 2.

[0038] On one main surface of the first sealing member 2, electrode pads 21 and 22 are provided in parallel on a rectangle having a long side and a short side. For the electrode pad 21, an electrode is drawn out to the other main surface through a metal via from the connection electrode 21a, and for the electrode pad 22, an electrode is drawn out to the other main surface through a metal via from the connection electrode 22a.

[0039] The second sealing member 3 is made of a rectangular plate-shaped AT-cut crystal plate and has the same outer shape and outer size as the crystal vibrating plate 2. A circumferential sealing film S22 corresponding to the sealing film S21 is formed on the surface of the second sealing member 3 facing the crystal vibrating plate 1.

[0040] Also, terminal electrodes 31, 32, 33, and 34 are formed on the surface of the second sealing member 3 not facing the crystal vibrating plate 1. Each of the terminal electrodes 31, 32, 33, and 34 has a rectangular shape and is formed at each corner of the second sealing member. The terminal electrodes 31 and 32 are electrically connected to the exciting electrodes 111 and 112, respectively, and the terminal electrodes 33 and 34 are electrically connected to the terminals 41 and 42 of the temperature sensor described later. Note that the metal film constituting these terminal electrodes has a laminated structure of a Ti film, a NiTi film, and an Au film.

[0041] In addition, in the second sealing member 3, metal vias V2 penetrating through the front and back are formed in the vicinity of the region corresponding to the holding portion 13 and are electrically connected to the above-described metal via V1. Further, metal vias V3 penetrating through the front and back are formed in the vicinity of the region corresponding to the holding portion 13t. With such a configuration, the lead-out electrode 111a formed on the crystal vibrator 1 is connected to the terminal electrode 31 via the metal via V2, and the lead-out electrode 112a is connected to the terminal electrode 32 via the metal via V3. Furthermore, metal vias V4 and V5 corresponding to the connection electrodes 121 and 122 are respectively formed, and the metal vias V4 and V5 are electrically connected to the terminal electrodes 33 and 34, respectively. With such a configuration, the terminal electrodes 31 and 32 of the crystal vibration device and the terminal electrodes 33 and 34 of the temperature sensor are arranged side by side on the long side and face each other. Note that, by changing the design of the electrode wiring, the two terminal electrodes of the crystal vibration device and the two terminal electrodes of the temperature sensor may be arranged diagonally.

[0042] A temperature sensor 4 is electrically and mechanically connected to the electrode pads 21 and 22 of the first sealing member 2. The temperature sensor 4 is a rectangular plate-shaped NTC thermistor. The rectangular plate-shaped thermistor element 40 has a thickness G2. A common electrode 43 is formed on the entire one main surface of the thermistor element 40, and rectangular electrode pads 41 and 42 are formed on the other main surface at regular intervals G1 in the long side direction.

[0043] The temperature sensor 4 forms terminals as a resistor with one electrode pad 41 and the other electrode pad 42 formed on the thermistor element 40, but the conduction path flows from the one electrode pad 41 through the common electrode 43 to the other electrode pad. With such a configuration, the cross-sectional area of the conduction path is greatly increased, and since the paths where the electrode pads and the common electrode surfaces face each other can be formed, the resistance value can be reduced with a small area, the characteristics are easily stabilized, and the withstand voltage can also be improved.

[0044] By the way, when the electrode pads 41 and 42 are configured to be close to each other, although it also depends on the voltage to be applied, the conductive path is dominated by the flow path from the electrode pad 41 to 42, and a desired resistance value may not be obtained. Therefore, in practice, the distance G2a between the electrode pad 41 and the common electrode 43, the distance G2b between the electrode pad 42 and the common electrode 43, and the distance G1 between the electrode pads 41 and 42 are set so as to satisfy G2a + G2b < G1. With such a setting, a desired resistance value can be obtained and the accuracy as a temperature sensor can be stabilized.

[0045] The larger the contact area between the temperature sensor and the crystal vibration device, the more accurately the temperature of the crystal vibration device can be detected. Therefore, it is better for the electrode pads formed on the temperature sensor to be larger with respect to the area of the temperature sensor. However, if they are too large, short circuits between adjacent electrode pads or short circuits due to conductive bonding materials are likely to occur. When the contact area becomes small, the temperature detection accuracy of the crystal vibration device decreases. Therefore, depending on the desired resistance value, if the total area of each electrode pad is 40% to 85% of the area of the temperature sensor, stable temperature detection can be performed. If it is less than 40%, the electrode pads of the temperature sensor become too small, and the temperature information of the crystal vibration device cannot be accurately detected. Also, when a thermistor is used for the temperature sensor, its resistance value becomes too high, and the temperature detection ability as a temperature sensor may decrease. On the other hand, if it is 85% or more, the risk of short circuits including the conductive bonding material increases, and if a short circuit occurs, it will not function as a temperature sensor.

[0046] Specific dimensional examples are shown below. The outer dimensions of the temperature sensor (the outer dimensions of the thermistor) are 0.8 mm for the long side, 0.6 mm for the short side, and 0.05 mm for the thickness, and its area is 0.48 mm2. Also, the outer dimensions of each electrode pad formed on the thermistor element are 0.52 mm for the long side (the short side of the thermistor element) and 0.3 mm for the short side (the long side of the thermistor element), and its area is 0.156 mm2. With such a configuration, the total area of each electrode pad is set to about 65% of the area of the temperature sensor. Also, the distance G2a between the electrode pad and the common electrode and the distance G2b between the electrode pad 42 and the common electrode 43 are each 0.05 mm, and the distance G1 between the electrode pads is set to 0.12 mm, and it is set so that G2a + G2b < G1 holds.

[0047] Other specific examples are shown below. The outer dimensions of the temperature sensor (the outer dimensions of the thermistor) are 0.7 mm for the long side, 0.6 mm for the short side, and 0.04 mm for the thickness, and its area is 0.42 mm2. Also, the outer dimensions of each electrode pad formed on the thermistor element are 0.58 mm for the long side (the short side of the thermistor element) and 0.3 mm for the short side (the long side of the thermistor element), and its area is 0.174 mm2. With such a configuration, the total area of each electrode pad is set to about 83% of the area of the temperature sensor. Also, the distance G2a between the electrode pad and the common electrode and the distance G2b between the electrode pad 42 and the common electrode 43 are each 0.04 mm, and the distance G1 between the electrode pads is set to 0.09 mm, and it is set so that G2a + G2b < G1 holds. Note that the above dimensions may be appropriately designed according to the size and characteristics of the crystal oscillator device and the required specifications of the crystal oscillator device with a temperature sensor.

[0048] The plate-shaped thermistor is made, for example, by making a slurry of an Mn-Fe-Ni-Ti-based material together with a binder or the like, creating a green sheet of the thermistor wafer using a thick film forming technique such as screen printing technology or doctor blade technology, and sintering and molding the plate-shaped thermistor wafer by a firing technique.

[0049] For this plate-shaped thermistor wafer, an electrode film (metal film) is formed by sputtering, and patterning is performed using photolithography technology. As a specific metal material, a laminated structure of a Ti film, a NiTi film, and an Au film similar to the metal film constituting the terminal electrode may be adopted, or other metal film configurations may be used. When the laminated structure of the Ti film, NiTi film, and Au film is adopted, when the thermistor is finally soldered to the mounting substrate, solder erosion is less likely to occur and stable conductive bonding can be performed. Also, the metal film configurations of the electrode pads 41 and 42 and the common electrode 43 may be different. For example, the metal film configurations of the electrode pads 41 and 42 may be a laminated structure of the Ti film, NiTi film, and Au film, and the metal film configuration of the common electrode may be a laminated structure of the Ti film and Au film.

[0050] By configuring a single-layer plate-shaped thermistor element with a metal film by means of thin film formation such as sputtering in this way, an extremely thin plate-shaped thermistor can be obtained. Note that the surface roughness of the plate-shaped thermistor may be reduced by lapping and polishing the surface in the state of a thermistor wafer. With such a configuration, the electrode film (metal film) can be formed stably, the manufacturing accuracy can be improved, and thus the performance as a temperature sensor can be made highly accurate.

[0051] As shown in FIG. 4, the crystal vibration device Xtl has a configuration in which a first sealing member 2, a crystal vibration plate 1, and a second sealing member 3 are stacked in this order. As described above, each of these constituent members is made of a crystal plate, and its surface is a smooth surface by mirror polishing. As a specific example, it is preferable that the average surface roughness Ra is 0.3 to 0.1 nm. By forming the seal films S11, S12, S21, and S22 on such a smooth surface, the metal film (uppermost Au film) on the surface also has a very smooth surface state.

[0052] The joining of the first sealing member 2, the crystal vibration plate 1, and the second sealing member 3 to the crystal vibration plate is performed by subjecting the Au of the metal film to surface treatment and then pressure-joining the two by diffusion bonding. As a result, the vibrating portion of the crystal vibration plate is hermetically sealed in a state surrounded by the sealing portions S1 (sealing films S11, S12), S2 (sealing films S21, S22), the respective sealing members 2, 3, and the frame portion 12. Note that the inside of the hermetic seal is a vacuum or an inert gas atmosphere.

[0053] A temperature sensor 4 is mounted on the upper surface of the crystal vibration device Xtl having the above-described configuration, that is, on one main surface of the first sealing member 2. Specifically, the electrode pads 21, 22 formed on the upper surface of the crystal vibration device Xtl and the electrode pads 41, 42 formed on the temperature sensor 4 composed of a plate-like thermistor are surface-bonded with conductive bonding materials R1, R1. The electrode pads 21, 22 are configured to have a larger area than the electrode pads 41, 42. As a result, the conductive bonding materials R1, R1 can conductively bond the crystal vibration device Xtl and the temperature sensor 4 in a state having a fillet, so that the bonding strength between the two can be improved. The conductive bonding material R1 is configured by adding a conductive filler such as silver powder or silver flakes to a paste-like silicone-based resin bonding material and has excellent thermal conductivity. This, combined with the fact that the electrode pads are surface-bonded to each other, results in good heat conduction, and the temperature of the crystal vibration device can be detected by the temperature sensor with high accuracy with little time lag. Note that as the conductive bonding material, other resins such as urethane-based resins or epoxy-based resins may be used in addition to the silicone-based resin.

[0054] As shown in Fig. 4, in this embodiment, the temperature sensor 4 made of a plate-shaped thermistor is configured to be coated with a resin material R2. The resin material R2 covers the upper surface of the crystal vibration device and is configured to cover the temperature sensor 4, the electrode pads 21 and 22 provided on the crystal vibration device, and the conductive bonding material R1. The resin material R2 used here is a composition in which a silica (SiO2) filler is added to an epoxy resin, and has a lower thermal conductivity than the conductive bonding material R1. Note that, in addition to the epoxy resin, other resin materials such as urethane resins and silicone resins may be used for the resin material R2. With such a configuration, an effect of suppressing heat detected by the temperature sensor from escaping to the outside can be obtained.

[0055] With the above configuration, temperature fluctuations of the crystal vibration device can be detected by the temperature sensor with little time lag via the electrode pads and the conductive bonding material. Further, since the temperature sensor is coated with a resin material having a lower thermal conductivity than the conductive bonding material, the temperature absorbed by the temperature sensor does not leak to the outside. As a result, the temperature at which the crystal vibration device is operating can be accurately detected, and high-precision temperature detection can be performed. In addition to the temperature sensor, an IC component having an oscillation circuit and a temperature compensation circuit may be mounted on the upper surface of the crystal vibration device and conductively bonded to the crystal vibration device and the temperature sensor. With such a configuration, a crystal vibration device constituting a temperature compensation type crystal oscillator can be obtained.

[0056] According to this embodiment, the thick portion 11a is formed along substantially the entire area of one end side where the holding portions 13 and 13t are formed in the vibrating portion 11, and the other end sides have a thickness configuration of a thin vibrating plate corresponding to a high frequency. Therefore, the vibration excited in the vibrating portion 11 can be made to vibrate in a state where it is less affected by the boundary conditions due to the thick portion 11a, whereby spurious and the like are less likely to occur, and a crystal vibrating plate with a good CI value (series resonance resistance) can be obtained. Further, the mechanical strength of the vibrating portion 11 can be improved by the thick portion 11a.

[0057] Further, as described above, the holding portion 13 has a thickness greater than or equal to that of the thick portion 11a, and a tapered portion is formed between the frame portion 12 and the holding portion 13, and between the thick portion 11a and the vibrating portion 11. As described above, the boundary can be rounded by this taper formation. As a result, the lead electrodes 111a and 112a drawn from the excitation electrodes 111 and 112 to one side edge of the crystal vibrating plate are formed on this tapered portion and do not pass through an acute-angled corner region (step portion). Therefore, a decrease in electrode conduction and electrode disconnection can be prevented. Thereby, a crystal vibrating plate with good electrical characteristics can be obtained.

[0058] According to the present embodiment, the frame portion 12 and the vibrating portion 11 are connected by a plurality of holding portions 13 and 13t, and the thickness of the holding portion 13t is smaller than the thickness of the holding portion 13. Therefore, while stabilizing the mechanical strength by the holding by the plurality of holding portions, it is possible to suppress the inhibition of the vibration of the vibrating portion by providing a holding portion with a small (thin) thickness. Thereby, a decrease in electrical characteristics as a crystal vibration device can be suppressed, and practical electrical performance can be ensured. Further, not limited to the present embodiment, the vibrating portion 11 may be connected by only one location of the holding portion 13.

[0059] In the crystal vibrating plate, this may be configured as a thin portion instead of the through portion. In this case, the vibrating portion is connected to the frame portion by the holding portion and the thin portion.

[0060] In the present embodiment, a multilayer structure of Ti and Au is exemplified as an example of the metal film of the excitation electrode and the metal film for sealing, but it is not limited to this metal film. For example, a multilayer structure of Ti, NiTi, and Au may be used.

[0061] Also, the bonding between each sealing member and the crystal vibrating plate was performed by the diffusion bonding method. However, for example, brazing with an AuSn alloy brazing material may be used, or other brazing materials such as Sn alloy brazing may be used. In the case of this brazing, the metal film configuration is also different. For example, a configuration in which an Ag or Cu film is formed on a Cr underlayer, or a configuration in which an alloy film with Au is formed may be used.

[0062] In the above description, the materials of the first sealing member and the second sealing member are crystal plates, but a glass material or a ceramic material may be used instead of the crystal plate. Also, although the shape is exemplified as a plate-like configuration, a concave portion may be provided at a position facing the crystal diaphragm. When the concave portion is provided in this way, the chance of contact between the vibrating portion and the sealing member can be reduced, so that the characteristics as a crystal vibration device can be stabilized.

[0063] Another embodiment will be described with reference to FIG. 7. In FIG. 7, the detailed configuration of the crystal vibration device is omitted. The temperature sensor 4 is mounted on the upper surface of the crystal vibration device, but the configuration and arrangement of the temperature sensor are different.

[0064] Electrode pads 23 and 24 are formed on the upper surface of the first holding member. These electrode pads are formed biased to the left side in the drawing, different from the above-described embodiment. As a result, a region where no electrode pad is formed can be secured on the upper surface of the first holding member. The region can be used as an adjustment region 25. When the first holding member is made of a light-transmitting material, the adjustment region 25 can transmit an energy beam B such as a laser beam. Therefore, the frequency of the crystal vibration device can be adjusted by irradiating the metal film formed on the crystal diaphragm with the energy beam to partially remove these metal films.

[0065] Also, an adjustment metal film is formed in advance inside the first holding member, and by irradiating the adjustment metal film with an energy beam, the adjustment metal film is vaporized and adhered to the metal film formed on the crystal diaphragm, whereby the frequency of the crystal vibration device can be adjusted.

[0066] The temperature sensor 4 has a configuration in which electrode pads 43 and 44 are formed on the other main surface of the thermistor element, and an electrode gap G3 is formed, but no electrode film is formed on one main surface. Therefore, a conductive path is formed between the electrode pads 43 and 44, and it functions as a thermistor.

[0067] By joining the electrode pads 43 and 44 to the electrode pads 23 and 24 with a conductive bonding material R1 made of solder, the two electrode pads are conductively surface-joined, thereby joining the two in a state with good thermal conductivity. In this embodiment, an insulating resin material R3 with good thermal conductivity is filled between the conductive bonding materials. With these configurations, the other main surface of the temperature sensor 4 is in a state of being surface-joined to the crystal vibration device over the entire surface.

[0068] And a resin material R2 is formed to cover the entire upper surface (one main surface) of the first holding member 2. As a result, the entire temperature sensor is also covered with the resin material R2. Note that the resin material R2 may be formed only in the temperature sensor R2 mounting region. In this case, since the adjustment region 25 is not covered with the resin material, there is an advantage that frequency adjustment can be performed by the energy beam B after joining the temperature sensor.

[0069] According to this embodiment, since the temperature sensor is joined to the crystal vibration device over substantially the entire other main surface with the conductive bonding material (solder) R1 and the insulating resin material R3, the temperature sensor 4 can surely and accurately capture the temperature change of the crystal vibration device. Also, by covering with the resin material R2, heat dissipation can be suppressed. With these configurations, a crystal vibration device with a temperature sensor capable of performing highly accurate temperature detection can be obtained. Furthermore, due to the adjustment region 25, the frequency of the crystal vibration device can be adjusted after hermetic sealing or after mounting the temperature sensor, so that the electrical characteristics can be improved.

[0070] The embodiments disclosed this time are illustrative in all respects and are not a basis for a limiting interpretation. Therefore, the technical scope of the present invention is not interpreted only by the above-described embodiments, but is defined based on the description in the claims. Also, all changes within the meaning and scope equivalent to the claims are included.

Explanation of Reference Numerals

[0071] 1 Crystal vibration plate 11 Vibration part 111, 112 Excitation electrodes 111a, 112a Lead-out electrodes 12 Frame part 13, 13t Holding parts 14 Through-hole part 2 First sealing member 3 Second sealing member 4 Temperature sensor S11, S12, S21, S22 Seal films S1, S2 Seal parts T1, T2, T3 Taper parts V1, V2, V3, V4, V5 Metal vias R1 Conductive bonding material R2 Resin material R3 Insulating resin material

Claims

1. A crystal oscillator device comprising a crystal vibrating plate, a first sealing member joined to the upper surface of the crystal vibrating plate, and a second sealing member joined to the lower surface of the crystal vibrating plate, and a temperature sensor joined to the first sealing member of the crystal oscillator device, wherein electrode pads are formed on the first sealing member and the temperature sensor, respectively, and the two electrode pads are surface-joined by a conductive bonding material, the temperature sensor has a configuration including a plate-shaped thermistor element, a pair of electrode pads formed on one main surface of the thermistor element, and a common electrode formed on the other main surface facing the pair of electrode pads, and the pair of electrode pads are conductively joined to the electrode pads of the first sealing member, the temperature sensor joined to the first sealing member is coated with a resin material, and the thermal conductivity of the resin material is smaller than the thermal conductivity of the conductive bonding material, let the distance between one of the pair of electrode pads formed on one main surface and the common electrode be G2a, let the distance between the other of the pair of electrode pads formed on one main surface and the common electrode be G2b, when the distance between one of the pair of electrode pads formed on one main surface and the other of the pair of electrode pads formed on one main surface is G1, it is set to satisfy G2a + G2b < G1 A crystal oscillator device with a temperature sensor, characterized by the above.

2. The crystal vibrating plate has a configuration including a vibrating portion formed with a pair of exciting electrodes, a holding portion protruding from at least one location of the vibrating portion, and a frame portion surrounding the outer periphery of the vibrating portion through a through portion and connected to the holding portion, The first sealing member and the second sealing member have a plate-like configuration, and the crystal vibrating plate, the first sealing member, and the second sealing member are mechanically joined by the frame portion. The crystal oscillator device with a temperature sensor according to Claim 1, characterized by the above.

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