JP2021027510A - Surface mounting type piezoelectric vibration device - Google Patents

Abstract

To provide a surface mounting type piezoelectric device having reliability which hardly causes characteristic deterioration.SOLUTION: A surface mounting type piezoelectric device includes: a base composed of a substantially rectangular substrate part 20 in a planar view with one principal surface at a lower side and the other principal surface at an upper side, and a first frame part 21 extending downward from a periphery of the one principal surface of the substrate; the first frame part in which an outer peripheral edge and an inner peripheral edge are substantially rectangular in a planar view and an external connection terminal is formed at four corners on its top surface; a plurality of first electrode pads 11 formed in a first recessed part surrounded with the first frame part and the one principal surface of the substrate; an electronic component element 4 mounted on the plurality of first electrode pads to have a temperature sensor function; a plurality of second electrode pads 7 formed on the other principal surface of the substrate; a piezoelectric vibration element 3 mounted on the plurality of second electrode pads; and a lid 5 for hermetically sealing the piezoelectric vibration element. The piezoelectric vibration element is connected by a conductive bonding material 8 only in an area overlapping the first recessed part in the plurality of second electrode pads in a planar view.SELECTED DRAWING: Figure 1

Description

The present invention relates to a surface mount piezoelectric vibration device.

Conventionally, as a piezoelectric device such as a piezoelectric vibrator or a piezoelectric oscillator, a surface mount type which is soldered to the surface of an external substrate has been widely used. For example, in a surface-mounted piezoelectric device, a piezoelectric vibrating element and an electronic component element such as an integrated circuit element (IC) or a thermistor are mounted on each of the front and back main surfaces of an insulating substrate, and the piezoelectric vibrating element is airtight using a lid. There is a structure sealed in. That is, the piezoelectric vibration element and the electronic component element are housed in separate spaces.

As a specific example of the above configuration, a lower surface formed by a lower surface of a flat plate-shaped substrate portion (main surface on the side facing the external substrate) and a frame portion (lower frame portion) provided on the outer peripheral portion of the lower surface portion. It is formed by a side recess, an upper surface of a flat plate-shaped substrate portion (a main surface opposite to the main surface on the side facing the external substrate), and a frame portion (upper frame portion) provided on the outer peripheral portion of the upper surface. Some are provided with an insulating base (so-called base having an H-shaped cross section) provided with an upper concave portion.

In the base, a piezoelectric vibration element is mounted in the upper recess, and an electronic component element such as an IC or a thermistor is mounted in the lower recess. Then, the piezoelectric vibrating element is hermetically sealed in the upper recess by joining a flat plate-shaped lid so as to close the opening of the upper recess. A surface mount type piezoelectric device having such a configuration is disclosed in Patent Document 1, for example, and shows a piezoelectric vibrator with a temperature sensor on which a thermistor is mounted as an electronic component element.

Since the piezoelectric vibrating element has a frequency temperature characteristic in which the frequency fluctuates depending on the ambient temperature, it is called a piezoelectric vibrator with a temperature sensor (hereinafter referred to as TSX) or a temperature-compensated piezoelectric oscillator (hereinafter referred to as TCXO). In the piezoelectric vibration device, in order to obtain more accurate frequency temperature characteristics, the frequency accuracy is improved by correcting the frequency of the piezoelectric vibration element on the circuit side based on the temperature information obtained from the temperature sensor of the electronic component element. It has become.

In an insulating base that includes a base having an H-shaped cross section as described above, has a lower concave portion of the base, and has an external connection terminal formed on the bottom surface of the lower frame portion, the peripheral portion is thick and the central portion is thin. Therefore, the base is liable to bend due to various stresses generated from the external substrate or the like. At this time, particularly in the piezoelectric vibrating element mounted on the substrate portion of the base, the influence of the stress applied to the holding portion becomes large and the characteristics are likely to deteriorate. In particular, the piezoelectric vibrating element has a frequency temperature characteristic in which the frequency fluctuates depending on the ambient temperature, but due to the influence of the stress in such a holding portion, a frequency shift occurs and the original frequency temperature characteristic is restored. The divergence is created (hysteresis).

Then, in the piezoelectric vibration device called TSX or TCXO, when the piezoelectric vibration element affected by the stress of the holding portion deviates from the frequency temperature characteristic of the original piezoelectric vibration element, the frequency information of the piezoelectric vibration element is used. There may be a discrepancy between the determined temperature information and the temperature information obtained from the temperature sensor of the electronic component element, and accurate frequency correction operation may not be possible.

JP 2016-178628

The present invention has been made in view of the above points, and an object of the present invention is to provide a surface mount type piezoelectric device having reliability in which characteristic deterioration is unlikely to occur.

In the present invention, in order to achieve the above object, it is configured as follows.
That is, in the surface-mounted piezoelectric device of the present invention, a substrate portion having a substantially rectangular shape in a plan view in which the lower portion is one main surface and the upper portion is the other main surface, and the first extending downward from the outer peripheral portion of one main surface of the substrate portion. A base composed of a frame portion, a first frame portion in which an outer peripheral edge and an inner peripheral edge are substantially rectangular in a plan view and external connection terminals are formed at four corners of the upper surface thereof, one of the first frame portion and the substrate portion. A plurality of first electrode pads formed in a first recess surrounded by a main surface, an electronic component element mounted on the plurality of first electrode pads and having a temperature sensor function, and formed on the other main surface of the substrate portion. It is provided with a plurality of second electrode pads, a piezoelectric vibrating element mounted on the plurality of second electrode pads, and a lid for airtightly sealing the piezoelectric vibrating element. It is joined by the conductive joining material only in the region of the second electrode pad that overlaps with the first recess in a plan view.

According to the present invention, the piezoelectric vibrating element is bonded by a conductive bonding material only in a region where it overlaps with the first recess in the first recess of the plurality of second electrode pads in a plan view, whereby an external substrate or the like is formed. Even if the base is bent due to various stresses generated from the above, since this joint region is at a position where the deformation displacement is small, the influence of the stress applied to the piezoelectric vibrating element is also small. Further, since the joint regions of the electronic component element and the piezoelectric vibration element stored in the first recess are close to each other on the surface facing the substrate portion, an error with respect to each other's temperature environment is less likely to occur.

As a result, the deviation of the frequency temperature characteristics of the piezoelectric vibrating element can be suppressed, and the error of the temperature information between the piezoelectric vibrating element and the electronic component element is eliminated. Therefore, when the frequency of the piezoelectric vibrating element is corrected, the accuracy is improved and the frequency is stable. A more reliable surface-mounted piezoelectric vibration device with a higher degree can be obtained.

Further, in addition to the above configuration, the center of gravity of the inner peripheral edge of the first frame portion and the center of gravity of the outer peripheral edge of the first frame portion coincide with each other, and the plane view area of the inner peripheral edge of the first frame portion is the first. It may be set between 1/3 and 2/3 of the plan view area of the outer peripheral edge of the frame portion. In this configuration, in addition to the above-mentioned effects, the area of the lower concave portion (first concave portion) of the base for accommodating the electronic component element is secured, whereas the joint region with the external substrate forming the external connection terminal is used. The optimum area allocation can be made from the viewpoint of securing a thick and high-strength area around the base.

That is, when the center of gravity of the inner peripheral edge of the first frame portion and the center of gravity of the outer peripheral edge of the first frame portion coincide with each other, the lower concave portion of the base is formed in the central portion, so that the bending stress of the base becomes uniform. Eliminates unnecessary stress concentration. If the plan view area of the inner peripheral edge of the first frame portion is smaller than 1/3 of the plan view area of the outer peripheral edge of the first frame portion, it becomes difficult to secure a storage space for the electronic component element. If the plan view area of the inner peripheral edge of the first frame portion is formed to be larger than two-thirds of the plan view area of the outer peripheral edge of the first frame portion, it becomes difficult to secure an area for forming the external connection terminal. The bonding strength with the substrate is reduced. Further, since the thick and high-strength region around the base is reduced, the base is likely to be bent by various stresses generated from the external substrate or the like.

Further, in addition to the above configuration, a substrate portion having a substantially rectangular plan view in which the lower portion is one main surface and the upper portion is the other main surface, and a first frame portion extending downward from the outer peripheral portion of one main surface of the substrate portion. A base composed of a second frame portion extending upward from the outer peripheral portion of the other main surface of the substrate portion, a second frame portion in which the outer peripheral edge and the inner peripheral edge are substantially rectangular in a plan view, the second frame portion and the substrate portion. It is provided with a plurality of second electrode pads formed in a second recess surrounded by another main surface, and the first recess has a smaller plan view area than the second recess and the second recess. It may be formed so as to overlap in a plan view inside the region of the recess. In this configuration, in addition to the above-mentioned action and effect, the area of the upper concave portion (second concave portion) of the base for accommodating the piezoelectric vibrating element is secured, and the thick and high-strength region of the peripheral portion of the base by the second frame portion is secured. Can be secured. Further, since the second recess can be formed to have a larger plane viewing area than the first recess, it does not hinder the mounting of a large piezoelectric vibration element at a lower frequency.

Further, in addition to the above configuration, the piezoelectric vibrating element may be hermetically sealed in a vacuum atmosphere by the base and the lid. In this configuration, in addition to the above-mentioned effects, the influence of the outer ring temperature on the piezoelectric vibrating element can be suppressed.

As described above, it is possible to provide a surface mount type piezoelectric device having reliability in which characteristic deterioration is unlikely to occur.

It is sectional drawing which shows the schematic structure of the crystal oscillator which concerns on embodiment of this invention. It is a bottom view of the crystal oscillator which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the embodiment of the present invention described below, as a surface mount piezoelectric vibration device, a surface mount type crystal oscillator (hereinafter, crystal oscillator) with a temperature sensor using a temperature sensitive element such as a thermistor as an electronic component element is an example. It will be explained by listing in.

An embodiment of the present invention will be described with reference to FIGS. 1 and 2. Note that FIG. 2 is a bottom view of the crystal oscillator, and a broken line shows a state in which the crystal vibrating element 3 is mounted on the pair of crystal mounting pads 7 and 7 via the conductive adhesive 8. It is shown transparently. The crystal oscillator 1 is a substantially rectangular parallelepiped package, and has a rectangular shape in a plan view and an H shape in a cross section. In the present embodiment, the external dimensions of the crystal oscillator 1 in a plan view are 1.6 mm on the long side (L direction in FIG. 2) and 1.2 mm on the short side (W direction in FIG. 2), and the oscillation frequency is It is 38.4 MHz to 76.8 MHz. The crystal oscillator 1 is mainly composed of a base 2, a crystal vibrating element 3, an electronic component element 4, and a lid 5. In this embodiment, a thermistor (hereinafter referred to as "thermistor 4"), which is a temperature sensor, is used as the electronic component element 4. The crystal oscillator 1 is externally temperature-compensated based on the temperature information obtained from the thermistor 4. Hereinafter, the outline of each member constituting the crystal oscillator 1 will be described.

The base 2 is a rectangular container in a plan view made of an insulating material. The base 2 has a flat plate-shaped substrate portion 20 and a first frame portion 21 in which the outer peripheral edge 210 and the inner peripheral edge 211 extend downward along the outer peripheral portion 200 of one main surface 201 of the substrate portion 20 and are substantially rectangular in a plan view. , The outer peripheral edge 220 and the inner peripheral edge 221 extend upward along the outer peripheral portion 200 of the other main surface 202 of the substrate portion 20, and the second frame portion 22 having a substantially rectangular plan view is a main constituent member (cross section substantially H type). It has become. Here, one main surface 201 of the substrate portion 20 is the main surface on the side facing the external substrate, and the other main surface 202 of the substrate portion 20 is on the side opposite to the main surface in which the thermistor 4 as an electronic component is housed. It is the main surface. In the present embodiment, each of the substrate portion 20, the first frame portion 21, and the second frame portion 22 is a ceramic green sheet (alumina), and these three sheets are integrally molded by firing in a laminated state. There is. Internal wiring having a predetermined shape is formed between the laminated sheets. In addition, each of these sheets (the sheet of the substrate portion, the sheet of the first frame portion, and the sheet of the second frame portion) is divided into not only a single layer but also a plurality of layers according to the extension form of the internal wiring between the layers. May be formed.

The space surrounded by the inner peripheral edge 221 of the second frame portion 22 of the base 2 and the other main surface 202 of the substrate portion is the second recess 2B. The second recess 2B has a substantially rectangular shape in a plan view and has the same shape as the inner peripheral edge 221 of the second frame portion 22. The inner peripheral edge of the upper second frame portion 22 around the second concave portion 2B is substantially rectangular in a plan view, and the four corners of the inner peripheral edge are arcuate in a plan view. A pair of crystal mounting pads 7 and 7 conductively bonded to the crystal vibrating element 3 are formed in parallel on one end side of the inner bottom surface (the other main surface 202 of the substrate portion 20) of the second recess 2B ( Only one is shown). One end side of the crystal vibrating element 3 is conductively bonded to the crystal mounting pad 7 by the conductive adhesive 8.

The space surrounded by the inner peripheral edge 211 of the first frame portion 21 of the base 2 and the one main surface 201 of the substrate portion is the first recess 2A. The first recess 2A is a square in a plan view and has the same shape as the inner peripheral edge 211 of the first frame portion 21. The size of the first recess 2A is smaller than that of the second recess 2B in a plan view, and the first recess 2A is included in the second recess 2B in the plan view transmission.

Further, in the present invention, the center of gravity O2 of the inner peripheral edge 211 of the first frame portion 21 and the center of gravity 01 of the outer peripheral edge 210 of the first frame portion coincide with each other, and the plane view area of the inner peripheral edge 211 of the first frame portion 21 is the first. It is desirable that the setting is between 1/3 to 2/3 (about 33.3% to 66.6%) of the plan view area of the outer peripheral edge 210 of the frame portion 211. Specifically, in the embodiment of the present invention, since the long side of the outer peripheral edge 210 of the first frame portion 21 is 1.6 mm and the short side is 1.2 mm, the outer peripheral edge 210 of the first frame portion 21 The plan view area is set to ^{1.92 mm 2.} On the other hand, since one side of the square first recess 2A (inner peripheral edge 211 of the first frame portion 21) is 0.85 mm, the plan-viewing area of the inner peripheral edge 211 of the first frame portion 21 is 0. It is set at 7225 mm ^2. Therefore, the plan view area of the inner peripheral edge 211 of the first frame portion 21 is set to be about 37% of the plan view area of the outer peripheral edge 210 of the first frame portion 211.

With this configuration, the center of gravity O2 of the inner peripheral edge 211 of the first frame portion 21 and the center of gravity O1 of the outer peripheral edge 210 of the first frame portion coincide with each other, so that the first concave portion 2A of the base 2 is formed in the central portion. Therefore, the bending stress of the base 2 becomes uniform and unnecessary stress concentration is eliminated. The plan view area of the inner peripheral edge 211 of the first frame portion 21 is set to be about 37% (between about 33.3% and 66.6%) of the plan view area of the outer peripheral edge 210 of the first frame portion 21. Therefore, the area of the thermistor 4 storage space described later and the external connection terminals 10a, 10b, 10c, and 10d described later can be formed in an optimum state. As a result, it is possible to secure a thick and high-strength region around the base without lowering the bonding strength with the external substrate, so that the base 2 can be less likely to be bent due to various stresses generated from the external substrate or the like.

In the present embodiment, the outer peripheral edge 210 of the first frame portion 21 has a rectangular shape in a plan view, and substantially matches the outer shape of the base 2 in a plan view. On the other hand, the inner peripheral edge 211 of the first frame portion 21, that is, the open end of the first recess 2A has a square shape in a plan view. Each side forming the open end of the first recess 2A is substantially parallel to the short side and the long side of the outer peripheral edge 210 of the first frame portion 21. Each of the four corners of the inner peripheral edge 211 of the first frame portion 21 has an arc shape in a plan view. That is, the four corners of the inner peripheral edge 211 of the first frame portion 21 have a plan view shape in which the corners of the square first recess 2A in a plan view are rounded into an arc shape (quarter circle shape). There is.

Notches 9a, 9b, 9c, and 9d are formed at the four corners of the outer peripheral edge 210 of the first frame portion 21 having a rectangular shape in a plan view. These notches 9a, 9b, 9c, 9d are notched so as to penetrate at least the first frame portion 21 in the vertical direction at each of the four ridges on the outer surface of the base 2, and are 4 minutes in a plan view. It is in the shape of a circle. A conductor is adhered to the inner wall surface of each of these four notched portions 9a, 9b, 9c, and 9d. Each conductor is connected to each of the four external connection terminals 10a, 10b, 10c, and 10d, which will be described later.

A pair of thermistor mounting pads 11 and 11 conductively bonded to the thermistor 4 are formed on the inner bottom surface of the first recess 2A, that is, on the other main surface 201 of the substrate portion 20 so as to face each other. The pair of thermistor mounting pads 11 and 11 are connected to the pair of drawer electrodes 12 and 12, respectively. The pair of lead-out electrodes 12 and 12 are electrically connected to the external connection terminals 10b and 10d for the thermistor via internal wiring, respectively. The pair of thermistor mounting pads 11 and 11 are conductively bonded to the electrodes 4E and 4E at both ends of the thermistor 4 by solder S. As the solder S, lead-free solder containing no lead (Pb) is used.

In this embodiment, the pair of thermistor mounting pads 11 and 11 are arranged so as to face each other in the short side direction of the outer peripheral edge 210 of the first frame portion 21. That is, the thermistor 4 has the thermistor mounting pad 11, so that the longitudinal direction of the thermistor 4 having a substantially rectangular parallelepiped shape, which will be described later, is orthogonal to the long side of the outer peripheral edge 210 of the first frame portion 21, that is, the long side of the base 2. It will be conductively bonded onto the 11. By mounting the thermistor 4 in such a positional relationship, it is possible to relieve the stress acting on the thermistor 4 after mounting the crystal oscillator 1 on the external substrate.

This is because the external substrate on which the crystal oscillator 1 is mounted may be bent due to bending stress or the like. When the external substrate bends, stress is also transmitted to the crystal oscillator 1 bonded to the external substrate via solder. The base 2 has a rectangular shape in a plan view, and the long side of the base has a relatively larger amount of deflection than the short side of the base. Therefore, it is better to join the thermistor 4 having a substantially rectangular parallelepiped shape in the first recess 2A so that the longitudinal direction of the thermistor 4 is orthogonal to the long side of the base 2, which is relatively easy to bend, so that it is parallel to the long side of the base 2. The thermistor 4 can be fixed in a direction in which the amount of deflection of the base 2 is smaller than that of joining in the first recess 2A. As a result, the bending stress acting on the thermistor 4 can be relaxed.

The base 2 composed of the second frame portion 22, the substrate portion 20, and the first frame portion 21 has substantially the same frame width between the second frame portion 22 and the first frame portion 21 in the cross-sectional view shown in FIG. Considering that, the package structure has an alphabetical "H" shape (H type) having a first recess 2A and a second recess 2B above and below the substrate portion 20. Due to such a package structure, the crystal vibrating element 3 and the thermistor 4 are housed in the upper and lower second recesses 2B and first recesses 2A, which are separate spaces, so that the influence of gas generated in the manufacturing process and other factors may occur. It has the effect of making it less susceptible to the effects of noise generated from the element. Further, since the crystal oscillator 3 and the thermistor 4 are housed in one base 2 in a state of being close to each other, the difference between the actual temperature of the crystal oscillator 3 and the measured value of the thermistor 4 can be reduced. it can. Further, since the crystal oscillator 1 in the present embodiment is a non-temperature compensating device that does not have a built-in temperature compensating circuit, good phase noise characteristics can be obtained.

As shown in FIG. 1, a metal film 6 is formed on the upper surface of the second frame portion 22 of the base 2. The metal film 6 and the sealing material (described later) formed on the lid 5 are heated in contact with each other to weld the lid 5 and the base 2. In the present embodiment, the metal film 6 is a gold-plated layer (Au), but a metal other than gold may be used. As a result, the crystal vibrating element 3 is airtightly sealed inside the space by the second recess 2B and the lid 5. At this time, it is desirable that the crystal piezoelectric vibrating element 3 is airtightly sealed in a vacuum atmosphere. With this configuration, the influence of the outer ring temperature on the crystal vibrating element 3 can be suppressed.

In FIG. 1, the crystal vibrating element 3 is a piezoelectric vibrating element having a rectangular shape in a plan view in which various electrodes are formed on the front and back main surfaces of an AT-cut crystal diaphragm. Although the description is omitted in FIG. 1, a pair of excitation electrodes are formed in a substantially central portion of the crystal vibrating element 3 so as to face each other on the front and back sides. The extraction electrode is drawn out from each of the pair of excitation electrodes toward one short edge of the front and back main surfaces of the crystal vibration element 3. The end portion of the extraction electrode is an electrode for joining, and is cantilevered and joined by the pair of crystal mounting pads 7 and 7 and the conductive adhesive 8. At this time, as shown by the broken line portion of FIG. 1 or 2, the crystal vibrating element 3 is conductive only in the region where it overlaps with the first recess 2A of the pair of crystal mounting pads 7 and 7 in a plan view. It is a feature of the present invention that they are joined by the adhesive 8. Although a silicone-based adhesive is used as the conductive adhesive 8 in the present embodiment, a conductive adhesive other than the silicone-based adhesive may be used.

With this configuration, even if the base 2 is bent due to various stresses generated from an external substrate or the like, the bonding region between the crystal vibrating element 3 and the pair of crystal mounting pads 7 and 7 (conductive adhesive). Since the joint portion with 8) is located at a position where the deformation displacement is small, the influence of the stress applied to the crystal vibrating element 3 is also small. Further, since the bonding regions of the crystal vibrating element 3 and the thermistor 4 housed in the first recess 2A are close to each other on the surface facing the substrate portion 20, an error with respect to each other's temperature environment is less likely to occur. As a result, the deviation of the frequency temperature characteristic of the crystal vibrating element 3 can be suppressed, and the error of the temperature information between the crystal vibrating element 3 and the thermistor 4 is eliminated. Therefore, when the frequency of the crystal vibrating element 3 is corrected, the accuracy is improved. A surface-mounted crystal unit with a more reliable temperature sensor with high frequency stability can be obtained.

In this embodiment, the thermistor 4 is used as the temperature sensor as described above. The thermistor 4 is a so-called NTC thermistor (Negative Temperature Coefficient Thermistor) whose resistance value decreases with increasing temperature, and a chip type thermistor corresponding to the miniaturization of a piezoelectric device is used. In FIG. 2, the thermistor 4 has a substantially rectangular parallelepiped shape, and its size in a plan view is 0.6 mm × 0.3 mm. The size of the thermistor in this embodiment is an example, and the thermistor other than the above size may be used. Further, not limited to the thermistor, another temperature sensor such as a diode may be used.

In FIG. 1, the lid 5 is a flat plate having a rectangular shape in a plan view. The lid 5 is made of Kovar as a base material, and the surface of the base material is nickel-plated and gold-plated. A gold-tin alloy (AuSn) is formed in a frame shape as a sealing material on the outer peripheral portion of the main surface of the lid 5 on the side to be joined to the base 2. A material other than the gold-tin alloy may be used as the sealing material.

In the present embodiment, as shown in FIG. 1, a via V that penetrates the inside of the second frame portion 22 and the substrate portion 20 and is filled with a conductor is formed therein. One end of the via V is exposed on the upper surface of the second frame portion 22, and is electrically connected to the metal film 6. On the other hand, the other end of the via V is connected to the internal wiring of the base 2 and is connected to the external connection terminal 10d via the internal wiring. That is, the metal lid 5 and the external connection terminal 10d are ground-connected. By connecting to the ground in this way, an electromagnetic shielding effect can be obtained. The above is an outline of each component of a surface mount type crystal unit with a temperature sensor (hereinafter referred to as a crystal unit).

Next, the external connection terminal will be described. As shown in FIG. 2, the bottom surface 212 of the first frame portion 21, that is, the outer peripheral edge of the bottom surface of the base 2 has a rectangular shape in a plan view, and the external connection terminals 10a are connected to each of the four corners of the bottom surface 212. 10b, 10c, 10d are formed. These four external connection terminals 10a, 10b, 10c, and 10d are terminals that are joined to the external board by soldering. In this embodiment, the external connection terminals 10a to 10d have a laminated structure of three types of metals. Specifically, in the external connection terminals 10a to 10d, a molybdenum layer is formed on the base material (ceramic) of the base 2 by a printing process, and the nickel plating layer and the gold plating layer are plated on the molybdenum layer in this order. It has a structure in which layers are laminated. The nickel plating layer and the gold plating layer are formed by an electrolytic plating method, and external connection terminals 10a to 10d and pads and the like are formed at the same time. The metal material constituting each layer of the external connection terminals 10a to 10d is an example, and other metal materials may be used. For example, tungsten may be used instead of molybdenum.

Of the four external connection terminals 10a, 10b, 10c, and 10d, the external connection terminals 10a and 10c are electrically connected to each excitation electrode (not shown) on the front and back main surfaces of the crystal vibration element 3. The remaining external connection terminals 10b and 10d are electrically connected to the electrodes 4E and 4E at both ends of the thermistor 4, respectively. That is, the external connection terminals 10a and 10c are external connection terminals for the crystal oscillator, and the external connection terminals 10b and 10d are external connection terminals for the thermistor. Here, the external connection terminals 10a and 10c for the crystal vibration element are not electrically connected to each other and are in a separate and independent state from the external connection terminals 10b and 10d for the thermistor. In other words, the external connection terminals 10a and 10c are electrically connected only to the excitation electrode of the crystal vibration element 3. The external connection terminals 10b and 10d are electrically connected only to the electrodes 4E and 4E at both ends of the thermistor 4.

Further, the four external connection terminals 10a, 10b, 10c, and 10d have a shape bent like the alphabet "L" which is long in the short side direction of the base 2 and short in the long side direction of the base 2 in a plan view. The inner peripheral edge side of this bent portion has an arc shape. As described above, the rectangular base 2 in a plan view has a larger deflection on the long side of the base than the short side of the base, and the amount of deflection in the central portion of the long side of the base is maximum. Therefore, the external connection terminal 10a , 10b, 10c, 10d do not preferably extend too much in the long side direction of the base. Therefore, in order to secure the solder bonding region, it is preferable to extend the tips of the external connection terminals 10a, 10b, 10c, and 10d long in the short side direction of the base.

Of the four external connection terminals 10a, 10b, 10c, and 10d, the external terminal 10c is formed with a notch 35 having a chamfered corner as shown in FIG. The notch 35 is provided as a mark for identifying the directionality of the four external connection terminals 10a, 10b, 10c, and 10d during image recognition.

In the above embodiment, a crystal oscillator using a thermistor as an electronic component element having a temperature sensor function has been described as an example, but a surface-mounted crystal oscillator using an IC having a temperature sensor function and an oscillation circuit is also used. Applicable.

Further, in the above-described embodiment of the present invention, a base having a substantially H-shaped cross section in which frame portions are formed on both the main surface side (lower side) and the other main surface side (upper side) of the substrate portion is described as an example. However, a base is used in which a frame portion is not formed on the other main surface side (upper side) of the substrate portion and a frame portion is formed only on one main surface side (lower side), and a cap-shaped lid having a recess on the lower side is used. It may be used and the crystal vibrating element mounted on the other main surface side (upper side) may be hermetically sealed.

The present invention can be practiced in various other ways without departing from its spirit or key features. Therefore, the above embodiments are merely exemplary in all respects and should not be construed in a limited way. The scope of the present invention is shown by the scope of claims, and is not bound by the text of the specification. Furthermore, all modifications and modifications that fall within the equivalent scope of the claims are within the scope of the present invention.

It can be applied to mass production of surface mount type piezoelectric vibration devices.

1 Crystal oscillator (surface mount type piezoelectric vibration device)
2 Base 2A 1st recess 2B 2nd recess 20 Board part 200 Outer circumference 201 1 Main surface 202 Other main surface 21 1st frame part 210 Outer circumference 211 Inner circumference 22 2nd frame 220 Outer circumference 221 Inner circumference 3 Crystal Vibration element (piezoelectric vibration element)
4 Thermistor (electronic component element)
5 Lid 6 Sealing part 7, 7 Crystal mounting pad 8 Conductive adhesive 9a, 9b, 9c, 9d Notch part 10a, 10b, 10c, 10d External connection terminal

Claims (4)

A base composed of a substantially rectangular substrate portion in a plan view in which the lower portion is one main surface and the upper portion is the other main surface, and a first frame portion extending downward from the outer peripheral portion of one main surface of the substrate portion.
The first frame portion, in which the outer peripheral edge and the inner peripheral edge are substantially rectangular in a plan view, and external connection terminals are formed at the four corners of the upper surface thereof.
A plurality of first electrode pads formed in a first recess surrounded by the first frame portion and one main surface of the substrate portion.
An electronic component element mounted on the plurality of first electrode pads and having a temperature sensor function.
A plurality of second electrode pads formed on the other main surface of the substrate portion,
Piezoelectric vibrating elements mounted on the plurality of second electrode pads,
A lid that airtightly seals the piezoelectric vibrating element,
And
The piezoelectric vibrating element is a surface mount type piezoelectric vibrating device characterized in that the piezoelectric vibrating element is joined by a conductive bonding material only in a region where the first concave portion of the plurality of second electrode pads overlaps in a plan view. The center of gravity of the inner peripheral edge of the first frame portion coincides with the center of gravity of the outer peripheral edge of the first frame portion, and the plan view area of the inner peripheral edge of the first frame portion is the plan view of the outer peripheral edge of the first frame portion. The surface-mounted piezoelectric vibration device according to claim 1, wherein the surface-mounted piezoelectric vibration device is set between 1/3 and 2/3 of the area. A board portion having a substantially rectangular plan view with one main surface at the bottom and another main surface at the top, a first frame portion extending downward from the outer peripheral portion of one main surface of the substrate portion, and the other main surface of the substrate portion. A base consisting of a second frame extending upward from the outer circumference,
The second frame portion, in which the outer peripheral edge and the inner peripheral edge are substantially rectangular in a plan view,
A plurality of second electrode pads formed in the second recess surrounded by the second frame portion and the other main surface of the substrate portion.
And
Claim 1 or claim 2 is characterized in that the first recess has a smaller plan view area than the second recess and is formed so as to overlap in a plan view inside the region of the second recess. The surface-mounted piezoelectric vibration device described in. The surface-mounted piezoelectric vibration device according to any one of claims 1 to 3, wherein the piezoelectric vibration element is hermetically sealed in a vacuum atmosphere by the base and the lid.

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