JP7703972B2 - Crystal device with temperature sensor - Google Patents

Description

The present invention relates to a quartz crystal resonator device with a temperature sensor, in which a temperature sensor is attached to a quartz crystal resonator device.

In recent years, with the increasing precision of various electronic devices, there is a demand for temperature-compensated crystal oscillation circuits that compensate for frequency fluctuations caused by changes in the environmental temperature. Crystal oscillators with temperature sensors, which have a thermistor or other temperature sensor attached to the crystal oscillator, are widely used as crystal oscillation devices that meet this requirement.

Such a crystal unit with a temperature sensor is configured such that the crystal unit is housed in a ceramic package and a thermistor is attached to the outside of the package to detect the environmental temperature surrounding the crystal unit. See Patent Document 1.

Depending on the application, the electronic devices may be required to be smaller and thinner, and in such cases, ultra-small or ultra-thin quartz crystal resonator devices are required. For example, mobile devices, wearable devices, etc. require ultra-small or ultra-thin quartz crystal resonator devices.

As a quartz crystal resonator device that meets such demands, a three-layered quartz crystal resonator device has been proposed in which a quartz crystal plate is hermetically sealed from above and below with thin sealing members (see Patent Document 2).
In addition, Patent Document 2 discloses an example in which a thermistor is used as a function section in a three-layered quartz crystal resonator.

Patent No. 5900582 Patent No. 5888347

In Patent Document 1, a ceramic package is used that has a storage compartment that opens in the top and bottom directions. A quartz crystal unit is stored in the upper opening and is conductively bonded to the package, and a thermistor is stored in the lower opening and is conductively bonded to the package.

This configuration uses a ceramic package and has two storage compartments, which makes it difficult to make the device smaller and thinner. In Patent Document 2, a thermistor is formed on a three-layered crystal unit. However, when the crystal unit and the thermistor are joined in an extremely small area, as shown in the drawings, and the upper part of the thermistor located on the upper surface of the crystal unit is open. This means that the heat transmitted is likely to dissipate, making it impossible to detect the temperature properly. Ultimately, the temperature of the crystal unit cannot be detected accurately, and proper temperature compensation cannot be performed. In such cases, the electrical characteristics of the crystal unit become unstable, which in turn makes the operation of the electronic device using the crystal unit unstable, reducing the reliability of the electronic device.

The present invention was made in consideration of the above problems, and aims to provide a crystal vibration device with a temperature sensor that is compatible with ultra-compact and ultra-thin designs, can stably and appropriately detect temperature fluctuations related to crystal vibration devices, and has excellent electrical characteristics.

A quartz crystal resonator device with a temperature sensor according to the present invention includes a quartz crystal resonator device including a quartz crystal plate, a first sealing member bonded to an upper surface of the quartz crystal plate, and a second sealing member bonded to a lower surface of the quartz crystal plate, and a temperature sensor bonded to the first sealing member of the quartz crystal resonator device, wherein electrode pads are formed on the first sealing member and the temperature sensor, and the electrode pads are surface-bonded to each other by a conductive bonding material, The temperature sensor is configured to include 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 opposing the pair of electrode pads, the pair of electrode pads being conductively joined to electrode pads of the first sealing member, the temperature sensor joined to the first sealing member being covered with a resin material, the thermal conductivity of the resin material being lower than the thermal conductivity of the conductive bonding material, and wherein, when a distance G2a is between one of the pair of electrode pads formed on one main surface and the common electrode, a distance G2b is between the other of the pair of electrode pads formed on the one main surface and the common electrode, and a distance G1 is between one of the pair of electrode pads formed on the one main surface and the other of the pair of electrode pads formed on the one main surface, the relationship G2a+G2b<G1 is satisfied.

The conductive bonding material may be a resin bonding material to which a conductive filler such as metal powder or metal chips has been added, or may be a metal brazing material such as solder. These conductive bonding materials bond the two electrode pads to each other by surface bonding, and due to the good thermal conductivity of metal materials, the temperature sensor can detect temperature changes in the quartz crystal resonator device with little time lag.

And because the temperature sensor is covered with the resin material, the heat transferred to the temperature sensor is not dissipated unnecessarily, so the temperature in the quartz crystal device can be accurately detected. As described above, the quartz crystal device has a three-layer structure consisting of a quartz crystal plate, a first sealing member, and a second sealing member, so the quartz crystal plate is more likely to follow changes in environmental temperature, and the temperature sensor can also detect temperature information corresponding to temperature fluctuations of the quartz crystal plate due to the good thermal conductivity provided by the surface bonding of each of the electrode pads.

The temperature information (e.g., current value, voltage value, resistance value, etc.) detected by this temperature sensor is connected to the outside via an independent terminal. Then, by using an external compensation circuit, etc., the frequency information in the quartz crystal device can be properly temperature compensated to obtain an accurate frequency.

The joint surface of the temperature sensor with the first sealing member may have multiple electrode pads formed thereon, and the total area of the electrode pads may be 40% to 85% of the area of the temperature sensor. The area here refers to the projected area, and the area ratio refers to the total projected area of the electrode pads relative to the projected area of the temperature sensor.

The larger the contact area of the temperature sensor with the quartz crystal device, the more accurately it can detect the temperature of the quartz crystal device. Therefore, the electrode pads formed on the temperature sensor should be larger than the area of the temperature sensor, but if they are too large, short circuits between adjacent electrode pads or short circuits due to the conductive bonding material are likely to occur. If the contact area becomes smaller, the accuracy of temperature detection of the quartz crystal device decreases. Therefore, stable temperature detection can be achieved if the total area of the electrode pads is 40% to 85% of the area of the temperature sensor.

The plate-shaped thermistor is manufactured using thick-film forming techniques such as screen printing or doctor blade technology, and sintering techniques, and Mn-Fe-Ni-Ti-based material is sintered 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 divided into individual pieces to obtain individual plate-shaped thermistors. The thermistor material may be an Mn-Fe-based material, etc.

Generally used thermistors (NTC thermistors) are constructed by laminating multiple layers of thermistor material with electrode (metal) films interposed between them using lamination technology, but the above construction has electrode (metal) films formed on both sides of a single layer of plate-shaped thermistor material. By forming a pair of electrode pads on one main surface of this plate-shaped thermistor element and 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 using PVD film-forming technology such as sputtering.

By conductively bonding such a plate-shaped thermistor to the electrode pad of a quartz crystal resonator device, it is possible to obtain a quartz crystal resonator device with a temperature sensor that can be made thinner and more compact.

Furthermore, the quartz crystal vibration plate may be configured to include a vibration portion on which a pair of excitation electrodes are formed, a holding portion formed to protrude from at least one point of the vibration portion, and a frame portion that surrounds the outer periphery of the vibration portion via a through-hole and is connected to the holding portion, and the first sealing member and the second sealing member may be configured to be plate-shaped, and the quartz crystal vibration plate and the first sealing member and the second sealing member may be configured to be mechanically joined by the frame portion.

According to the above configuration, a thin quartz crystal vibration device is configured in which a plate-shaped quartz crystal vibration plate, a first sealing member, and a second sealing member are bonded, and a temperature sensor such as a thermistor is bonded to this quartz crystal vibration device, so that a quartz crystal vibration device with a temperature sensor that can be made thin and compact can be obtained. Since the vibration part is connected by a holding part that is formed by protruding from at least one place, it is less susceptible to the effects of external stress. In particular, the characteristics of the vibration part are stabilized because the effects of external stress caused by the conductive bonding material and resin material generated when bonding the thermistor are less likely to be transmitted to the vibration part.

The quartz crystal plate may be an AT-cut or SC-cut quartz crystal plate, or an XY-cut quartz crystal plate, etc.

The present invention makes it possible to obtain a crystal vibration device with a temperature sensor that is compatible with ultra-compact and ultra-thin designs, can properly detect temperature fluctuations related to the crystal vibration device, and has excellent electrical characteristics.

1 is an exploded perspective view showing each component of a crystal vibration device with a temperature sensor according to an embodiment of the present invention; FIG. 2 is a plan view of one of the main surfaces of the quartz crystal plate. 13 is a plan view of the other main surface (bottom surface) of the second sealing member. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1 when the components are assembled. FIG. 2 is a plan view of one main surface of a plate-shaped thermistor. 4 is a plan view of the other main surface of the plate-shaped thermistor. FIG. FIG. 4 is a cross-sectional view showing another example of a plate-shaped thermistor.

The following describes in detail the embodiments of the present invention with reference to the drawings.

The crystal vibration device Xtl with temperature sensor according to the first embodiment comprises a crystal vibration device and a temperature sensor, and as shown in Fig. 1, the crystal vibration device Xtl comprises a crystal vibration plate 1, a first sealing member 2, and a second sealing member 3, and is stacked in this order: the first sealing member 2, the crystal vibration plate 1, and the second sealing member 3. The temperature sensor 4 is conductively bonded to the top surface of the crystal vibration device.

The quartz crystal plate 1 is an AT-cut quartz crystal plate, and is a rectangular plate overall. The quartz crystal plate 1 is composed of a vibrating part 11, holding parts 13, 13t connected to the two corners of the vibrating part 11, and a frame part 12 that is disposed on the outer periphery of the vibrating part and connected to the holding parts 13, 13t. A through part 14 is formed circumferentially between the vibrating part 11 and the frame part 12, except for the holding parts 13, 13t.

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

Specifically, the extraction electrode 111a passes through the surface of the holding portion 13, is drawn 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 below. The metal via V2 is electrically connected to a terminal electrode 31 formed on the other main surface of the second sealing member 3. The extraction electrode 112a passes through the back surface of the holding portion 13t, is drawn out to the other surface of the quartz crystal 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.

These excitation electrodes 111, 112 and extraction electrodes 111a, 112a are made of multiple layers of metal films, and have a multi-layer structure in which, for example, a Ti film is formed in contact with the quartz crystal plate, and an Au film is formed on top of that. Specific examples of the thickness of each metal film include a Ti film of 5 nm and an Au film of 200 nm, but these may be changed depending on the desired characteristics.

A thick portion 11a is formed on one end edge of the vibration part 11. The thick portion 11a is formed on one end edge in the X-axis direction, extends in the Z'-axis direction, and is formed over the entire end edge. The thick portion 11a is formed to be thicker than the vibration part 11.

As shown in FIG. 2, a holding portion 13 is provided at one corner C1 of the vibration portion 11, and a holding portion 13t is provided at another corner C2, with each holding portion 13, 13t being connected to the frame portion 12. In this embodiment, the vibration portion, holding portion, and frame portion are integrally formed from a quartz plate using photolithography and wet etching techniques. Note that dry etching techniques may be used instead of wet etching.

As shown in Figs. 1 and 4, the holding portion 13 is configured to be thicker than the vibration portion 11 and the thick portion 11a, and a sloped taper T2 is formed from the thick portion 11a to the upper surface of the holding portion 13, and a sloped taper T3 is also formed from the vibration portion 11 to the holding portion 13. The holding portion 13 is connected to the frame portion 12, and a taper T1 is formed from the holding portion 13 to the upper surface of the frame portion 12. With this configuration, the thicknesses are set as follows: vibration 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 tapers, the boundary region can be made obtuse. Note that when the step of the boundary region is small, or when the risk of disconnection is low, there is no practical problem in not forming the taper.

Specific dimensions of the quartz vibration plate are shown below. A rectangular AT-cut quartz vibration plate is used for the quartz vibration plate, with external dimensions of 1.2 mm wide and 1.0 mm long, the external dimensions of the vibration part are 0.7 mm wide and 0.7 mm long, the frame part is 0.2 mm wide and 0.1 mm long, and the dimensions of the holding part are 0.05 mm wide and 0.15 mm long. The thicknesses of the various components are 0.04 mm for the frame part, 0.03 mm for the holding part, 0.017 mm (17 μm) for the thick part, and 0.005 mm (5 μm) for the vibration part. It is preferable that the thick part is 10 μm or more thicker than the vibration part in order to ensure mechanical strength.

In this embodiment, a configuration is adopted in which the quartz crystal plate 1 is thinned from only one of its main surfaces. For example, the thinning is performed from only one of the main surfaces by etching technology until the desired frequency (thickness) is reached. In this case, the other main surface is not etched, so that deterioration of vibration characteristics due to roughening of the surface caused by etching can be suppressed. Note that a configuration in which thinning is performed from both main surfaces may also be adopted.

Sealing films S11 and S21 are formed around the outer periphery of the front and back of the frame body 12. Similar to the electrode film described above, these sealing films have a multi-layer structure in which a Ti film is formed in contact with the quartz crystal plate and an Au film is formed on top of that.

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

The first sealing member 2 is made of a rectangular, plate-like AT-cut quartz crystal plate and has the same external shape and size as the quartz crystal vibration plate 2. A peripheral sealing film S12 corresponding to the sealing film S11 is formed on the other main surface of the first sealing member 2 (the surface facing the quartz crystal vibration plate 1).

In addition, rectangular electrode pads 21 and 22 having long and short sides are arranged in parallel on one main surface of the first sealing member 2, and the electrode of the electrode pad 21 is extended from the connection electrode 21a to the other main surface via a metal via, and the electrode of the electrode pad 22 is extended from the connection electrode 22a to the other main surface via a metal via.

The second sealing member 3 is made of a rectangular, plate-like AT-cut quartz crystal plate, and has the same outer shape and outer size as the quartz crystal vibration plate 2. A peripheral sealing film S22 corresponding to the sealing film S21 is formed on the surface of the second sealing member 3 facing the quartz crystal vibration plate 1.

In addition, terminal electrodes 31, 32, 33, and 34 are formed on the surface of the second sealing member 3 that does not face the quartz crystal 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 excitation 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 below. The metal films that make up these terminal electrodes have a laminated structure of a Ti film, a NiTi film, and an Au film.

In addition, a metal via V2 is formed in the second sealing member 3 near the area corresponding to the holding portion 13, and is electrically connected to the metal via V1 described above. A metal via V3 is formed near the area corresponding to the holding portion 13t, and is connected to the front and back. With this configuration, the lead electrode 111a formed on the quartz crystal plate 1 is connected to the terminal electrode 31 through the metal via V2, and the lead electrode 112a is connected to the terminal electrode 32 through the metal via V3. Furthermore, metal vias V4 and V5 corresponding to the connection electrodes 121 and 122, respectively, are formed, and the metal vias V4 and V5 are electrically connected to the terminal electrodes 33 and 34, respectively. With this configuration, the terminal electrodes 31 and 32 of the quartz crystal device and the terminal electrodes 33 and 34 of the temperature sensor are arranged side by side on the long sides and are opposed to each other. Note that the design of the electrode wiring may be changed to arrange the two terminal electrodes of the quartz crystal device and the two terminal electrodes of the temperature sensor diagonally.

The 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, and the rectangular plate-shaped thermistor element 40 has a thickness G2. A common electrode 43 is formed over the entire surface of one main surface of the thermistor element 40, and rectangular electrode pads 41 and 42 are formed on the other main surface with a fixed interval G1 in the long side direction.

The temperature sensor 4 has a resistor terminal formed by one electrode pad 41 and the other electrode pad 42 formed on the thermistor element 40, and the conductive path flows from the one electrode pad 41 to the other electrode pad via the common electrode 43. This configuration greatly increases the cross-sectional area of the conductive path, and also allows the electrode pad and the common electrode to face each other on their surfaces, so that the resistance value can be reduced with a small area, characteristics can be stabilized, and the withstand voltage can be improved.

However, when the electrode pads 41 and 42 are arranged close to each other, depending on the applied voltage, the conductive path may be dominated by the flow path from electrode pad 41 to 42, and the desired resistance value may not be obtained. Therefore, in practice, the distance G2a between electrode pad 41 and common electrode 43, the distance G2b between electrode pad 42 and common electrode 43, and the distance G1 between electrode pads 41 and 42 are set to satisfy G2a + G2b < G1. With such settings, the desired resistance value can be obtained and the accuracy as a temperature sensor can be stabilized.

The larger the contact area of the temperature sensor with the quartz crystal device, the more accurately it can detect the temperature of the quartz crystal device. Therefore, the electrode pads formed on the temperature sensor should be larger than the area of the temperature sensor, but if they are too large, short circuits between adjacent electrode pads or short circuits due to the conductive bonding material are likely to occur. If the contact area is small, the temperature detection accuracy of the quartz crystal 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 the total area of each electrode pad is less than 40%, the electrode pads of the temperature sensor will be too small and will not be able to accurately detect the temperature information of the quartz crystal device, and if a thermistor is used as the temperature sensor, its resistance value will be too high, which may reduce the temperature detection ability of the temperature sensor. If the total area is more than 85%, the risk of short circuits including the conductive bonding material increases, and if a short circuit occurs, the temperature sensor will not function.

Specific dimensional examples are shown below. The external size of the temperature sensor (external size of the thermistor) is 0.8 mm long, 0.6 mm short, and 0.05 mm thick, resulting in an area of 0.48 mm2. The external size of each electrode pad formed on the thermistor element is 0.52 mm long (short side of the thermistor element) and 0.3 mm short (long side of the thermistor element), resulting in an area of 0.156 mm2. With this configuration, the total area of each electrode pad is set to approximately 65% of the area of the temperature sensor, and 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 set to 0.05 mm, and the distance G1 between the electrode pads is set to 0.12 mm, so that G2a + G2b < G1 holds.

Other specific examples are shown below. The outer size of the temperature sensor (outer size of the thermistor) is 0.7 mm long, 0.6 mm short, and 0.04 mm thick, resulting in an area of 0.42 mm2. The outer size of each electrode pad formed on the thermistor element is 0.58 mm long (short side of the thermistor element) and 0.3 mm short (long side of the thermistor element), resulting in an area of 0.174 mm2. With this configuration, the total area of each electrode pad is set to about 83% of the area of the temperature sensor, and 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 set to 0.04 mm, respectively, and the distance G1 between the electrode pads is set to 0.09 mm, so that G2a + G2b < G1 holds. The above dimensions may be designed appropriately according to the size and characteristics of the quartz crystal resonator device and the required specifications of the quartz crystal resonator device with temperature sensor.

For example, plate-shaped thermistors are made by mixing Mn-Fe-Ni-Ti-based materials with a binder to form a slurry, then using a thick-film forming technique such as screen printing or doctor blade to create a green sheet of thermistor wafer, which is then sintered into a plate-shaped thermistor wafer using a firing technique.

An electrode film (metal film) is formed on this plate-shaped thermistor wafer by sputtering, and patterned using photolithography technology. A specific metal material may be a laminated structure of Ti film, NiTi film, and Au film, similar to the metal film constituting the terminal electrode, or another metal film structure. When the laminated structure of Ti film, NiTi film, and Au film is adopted, when the thermistor is finally soldered to the mounting board, solder erosion is unlikely to occur and a stable conductive bond can be achieved. In addition, the metal film structure of the electrode pads 41, 42 and the metal film structure of the common electrode 43 may be different. For example, the metal film structure of the electrode pads 41, 42 may be a laminated structure of Ti film, NiTi film, and Au film, and the metal film structure of the common electrode may be a laminated structure of Ti film and Au film.

In this way, by forming a metal film on a single-layer plate thermistor element using a thin-film forming method such as sputtering, an extremely thin plate thermistor can be obtained. The surface roughness of the plate thermistor can be reduced by lapping and polishing the surface while it is in the thermistor wafer state. With this configuration, the electrode film (metal film) can be formed stably and manufacturing precision can be improved, resulting in high-precision performance as a temperature sensor.

As shown in FIG. 4, the quartz crystal device Xtl is constructed by stacking a first sealing member 2, a quartz crystal plate 1, and a second sealing member 3 in that order. As mentioned above, each of these components is made of a quartz crystal plate, and its surface is made smooth 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 sealing films S11, S12, S21, and S22 on such a smooth surface, the metal film on the surface (the top layer Au film) also has a very smooth surface condition.

The first sealing member 2 and the quartz vibration plate 1, and the quartz vibration plate and the second sealing member 3 are bonded by pressure bonding using a diffusion bonding method after surface treatment of the Au of the metal film. As a result, the vibration part of the quartz vibration plate is hermetically sealed in a state surrounded by the sealing members 2 and 3 and the frame part 12 by the sealing parts S1 (sealing films S11, S12) and S2 (sealing films S21, S22). The inside of the hermetically sealed part is a vacuum or inert gas atmosphere.

The temperature sensor 4 is mounted on the upper surface of the quartz crystal resonator device Xtl having the above configuration, i.e., on one of the main surfaces of the first sealing member 2. Specifically, the electrode pads 21, 22 formed on the upper surface of the quartz crystal resonator device Xtl and the electrode pads 41, 42 formed on the temperature sensor 4 consisting of a plate-shaped 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, and thus the conductive bonding materials R1, R1 can conductively bond the quartz crystal resonator device Xtl and the temperature sensor 4 in a state in which they have a fillet, thereby improving the bonding strength between the two. The conductive bonding material R1 is a paste-like silicone resin bonding material to which a conductive filler such as silver powder or silver flakes is added, and has excellent thermal conductivity. This, combined with the surface bonding of the electrode pads, provides good thermal conductivity, and the temperature detection of the quartz crystal resonator device by the temperature sensor can be measured with high accuracy with little time lag. In addition to silicone resin, other resins such as urethane resin and epoxy resin may be used as the conductive bonding material.

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

With the above configuration, the temperature fluctuation of the quartz crystal resonator device can be detected by the temperature sensor with little time lag via the electrode pads and the conductive bonding material, and since the temperature sensor is covered with a resin material with a lower thermal conductivity than the conductive bonding material, the heat absorbed by the temperature sensor does not leak to the outside. This allows the operating temperature of the quartz crystal resonator device to be accurately detected, allowing for highly accurate temperature detection. In addition to the temperature sensor, an IC component equipped with an oscillation circuit and a temperature compensation circuit may be mounted on the top surface of the quartz crystal resonator device and conductively bonded to the quartz crystal resonator device and the temperature sensor. With this configuration, a quartz crystal resonator device constituting a temperature-compensated quartz crystal oscillator can be obtained.

According to this embodiment, the vibrating part 11 has a thick portion 11a formed along almost the entire area of one end side where the holding parts 13 and 13t are formed, and the other end side has a thickness of a thin diaphragm corresponding to high frequencies. Therefore, the vibration excited by the vibrating part 11 can be caused in a state where it is less affected by the boundary conditions caused by the thick portion 11a, and it is possible to obtain a quartz crystal vibrating plate which is less likely to generate spurious signals and can maintain a good CI value (series resonance resistance). The thick portion 11a also improves the mechanical strength of the vibrating part 11.

As mentioned above, the holding portion 13 is thicker than or has the same thickness as the thick portion 11a, and tapered portions are formed between the frame portion 12 and the holding portion 13, and between the thick portion 11a and the vibration portion 11. As mentioned above, this tapering allows the boundaries to be made obtuse. As a result, the extraction electrodes 111a, 112a drawn from the excitation electrodes 111, 112 to one end side of the quartz vibration plate are formed on this tapered portion and do not pass through an acute corner area (step portion), preventing a decrease in electrode conductivity and electrode breakage. This makes it possible to obtain a quartz vibration plate with good electrical characteristics.

According to this embodiment, the frame portion 12 and the vibration portion 11 are connected by multiple holding portions 13, 13t, but the thickness of the holding portion 13t is configured to be smaller than the thickness of the holding portion 13. Therefore, the mechanical strength is stabilized by the holding by multiple holding portions, and by providing a holding portion with a small (thin) thickness, it is possible to suppress the inhibition of the vibration of the vibration portion. This suppresses the deterioration of the electrical characteristics as a quartz vibration device, and ensures practical electrical performance. Also, this is not limited to this embodiment, and the vibration portion 11 may be connected at only one point of the holding portion 13.

In addition, in the quartz crystal vibration plate, the through-hole may be replaced by a thin-walled portion. In this case, the vibration portion is connected to the frame portion by the holding portion and the thin-walled portion.

In this embodiment, a multilayer structure of Ti and Au is given as an example of the metal film of the excitation electrode and the metal film for sealing, but the metal film is not limited to this. For example, a multilayer structure of Ti, NiTi, and Au is also acceptable.

In addition, the bonding between each sealing member and the quartz crystal plate was performed by diffusion bonding, but for example, soldering using an AuSn alloy solder material may be used, or other solder materials such as Sn alloy solder may be used. In the case of this soldering, the metal film configuration may also be different, for example, a configuration in which an Ag or Cu film is formed on a Cr base layer, or a configuration in which an alloy film with Au is formed.

In the above description, a quartz plate is used as the material for the first and second sealing members, but a glass or ceramic material may be used instead of the quartz plate. The shape of the sealing member is also exemplified as a plate-like structure, but a recess may be provided at a position opposite the quartz vibration plate. If a recess is provided in this way, the chance of contact between the vibration part and the sealing member can be reduced, thereby stabilizing the characteristics of the quartz vibration device.

Another embodiment will be described with reference to FIG. 7. In FIG. 7, the detailed configuration of the quartz crystal vibration device is omitted. In this configuration, a temperature sensor 4 is mounted on the top surface of the quartz crystal vibration device, but the configuration and arrangement of the temperature sensor are different.

Electrode pads 23 and 24 are formed on the upper surface of the first holding member. Unlike the above embodiment, these electrode pads are formed biased toward the left side of the drawing. As a result, an area on the upper surface of the first holding member where no electrode pads are formed can be secured. This area can be used as an adjustment area 25. If the first holding member is made of a translucent material, adjustment area 25 can transmit an energy beam B such as a laser beam. Therefore, the frequency of the quartz crystal device can be adjusted by irradiating the metal films formed on the quartz crystal plate with the energy beam to remove part of the metal films.

In addition, an adjustment metal film is formed in advance on the inside of the first holding member, and an energy beam is irradiated onto this adjustment metal film, vaporizing the adjustment metal film and causing it to adhere to the metal film formed on the quartz crystal plate, thereby adjusting the frequency of the quartz crystal device.

The temperature sensor 4 has electrode pads 43 and 44 formed on the other main surface of the thermistor element, and an interelectrode 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 the temperature sensor 4 functions as a thermistor.

The electrode pads 43, 44 are joined to the electrode pads 23, 24 with a conductive bonding material R1 made of solder, so that the two electrode pads are surface-bonded conductively, thereby bonding the two together with good thermal conductivity. In this embodiment, insulating resin material R3 with good thermal conductivity is filled between the conductive bonding materials. With this configuration, the other main surface of the temperature sensor 4 is surface-bonded to the quartz crystal resonator device over the entire surface.

Then, the resin material R2 is formed to cover the entire upper surface (one of the main surfaces) of the first holding member 2. This results in the entire temperature sensor being covered with the resin material R2. The resin material R2 may be formed only in the area where the temperature sensor R2 is mounted. In this case, the adjustment area 25 is not covered with the resin material, which has the advantage that frequency adjustment can be performed using the energy beam B after the temperature sensor is joined.

According to this embodiment, the temperature sensor is bonded to the quartz crystal resonator device over almost the entire other main surface with a conductive bonding material (solder) R1 and an insulating resin material R3, so that the temperature sensor 4 can reliably and accurately capture the temperature change of the quartz crystal resonator device. In addition, by covering with the resin material R2, heat dissipation can also be suppressed. With this configuration, it is possible to obtain a quartz crystal resonator device with a temperature sensor that can perform highly accurate temperature detection. Furthermore, the adjustment region 25 allows the frequency of the quartz crystal resonator device to be adjusted after hermetically sealing or after the temperature sensor is attached, thereby improving the electrical characteristics.

The embodiments disclosed herein are illustrative in all respects and are not intended to be a basis for a restrictive interpretation. Therefore, the technical scope of the present invention is not to be interpreted solely by the above-described embodiments, but is defined based on the claims. Furthermore, all modifications within the scope and meaning equivalent to the claims are included.

REFERENCE SIGNS LIST 1 quartz crystal plate 11 vibration portion 111, 112 excitation electrode 111a, 112a extraction electrode 12 frame portion 13, 13t holding portion 14 penetration portion 2 first sealing member 3 second sealing member 4 temperature sensor S11, S12, S21, S22 sealing film S1, S2 sealing portion T1, T2, T3 tapered portion V1, V2, V3, V4, V5 metal via R1 conductive bonding material R2 resin material R3 insulating resin material

Claims (2)

A quartz crystal vibration device with a temperature sensor, comprising: a quartz crystal vibration plate; a first sealing member bonded to an upper surface of the quartz crystal vibration plate; and a second sealing member bonded to a lower surface of the quartz crystal vibration plate; and a temperature sensor bonded to the first sealing member of the quartz crystal vibration device,
Electrode pads are formed on the first sealing member and the temperature sensor, respectively, and the electrode pads are surface-bonded to each other by a conductive bonding material;
The temperature sensor is configured to include 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 being conductively joined to electrode pads of the first sealing member,
the temperature sensor joined to the first sealing member is covered with a resin material, and the thermal conductivity of the resin material is lower than the thermal conductivity of the conductive bonding material;
The distance between one of a pair of electrode pads formed on one main surface and the common electrode is G2a,
The distance between the other electrode pad of the pair of electrode pads formed on one main surface and the common electrode is G2b,
When a distance between one of the pair of electrode pads formed on the one main surface and the other of the pair of electrode pads formed on the one main surface is G1,
A quartz crystal resonator device with a temperature sensor, characterized in that G2a + G2b < G1 is satisfied. The quartz crystal plate is configured to include a vibration part on which a pair of excitation electrodes are formed, a holding part formed to protrude from at least one point of the vibration part, and a frame part surrounding the outer periphery of the vibration part via a through part and connected to the holding part,
2. The quartz crystal vibration device with temperature sensor according to claim 1, wherein the first sealing member and the second sealing member have a plate-like structure, and the quartz crystal vibration plate and the first sealing member and the second sealing member are mechanically joined by the frame portion.

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