JP2013138293A - Piezoelectric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric device accommodating a temperature sensor and a piezoelectric vibration element in a package, that can use the same electrode pad for sensor parts regardless of the size of the temperature sensor.SOLUTION: A piezoelectric device accommodates a piezoelectric element 10 on which an excitation electrode is formed and a temperature sensor in a package 1. The package 1 includes a base plate, a set of electrode pads 41, 42 for sensor parts which are on the base plate and conductively connected to the temperature sensor 80, and another set of electrode pads for sensor parts which are on the base plate and conductively connected to the temperature sensor 80. The two sets of electrode pads each include a first electrode pad for sensor parts and a second electrode pad for sensor parts. The first electrode pads for sensor parts are commonly connected, the second electrode pads for sensor parts are commonly connected, and only one set of electrode pads for sensor parts can mount the temperature sensor.

Description

  The present invention relates to a piezoelectric device including a sensor component serving as a temperature sensor in a package.

  Piezoelectric vibrators used in piezoelectric devices have temperature characteristics in which the frequency varies with the ambient temperature. However, for example, in a piezoelectric device used in a mobile communication device or the like, the fluctuation range of the oscillation frequency is very small and high accuracy is required. For this reason, a piezoelectric device having a configuration in which a temperature sensor having a unique output is placed in the vicinity of a piezoelectric element and temperature compensation is performed by an external circuit based on information of the temperature sensor has been considered. For example, Japanese Patent Application Laid-Open No. 2005-286892 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2008-205938 (Patent Document 2) are prior arts showing examples thereof.

JP 2005-286892 A JP 2008-205938 A

Temperature sensors built into piezoelectric devices include thermistors and diodes. The temperature sensor is appropriately selected depending on the required specifications of the piezoelectric device, the package configuration, and the like, but a temperature sensor having a different external size may be used. In such a case, a configuration in which the electrode pad for mounting the temperature sensor is considered in consideration of a small temperature sensor can be considered, but when connected with a metal brazing material such as solder or a conductive bonding material such as a conductive resin adhesive In addition, there is a problem that the conductive bonding material flows between the narrow electrodes and short-circuits. In addition, the narrow inter-electrode configuration may cause a short circuit of a temperature sensor having a large outer size.

The present invention has been made to solve the above-described problems. Therefore, the object of the present invention is to make it possible to mount sensor parts serving as temperature sensors of different sizes in a package, and to prevent the occurrence of a short circuit problem. The purpose is to provide a device.

The present invention relates to a piezoelectric device in which an excitation electrode is formed and a temperature sensor housed in a package, the package comprising a substrate and two sets of electrode pads for sensor components that are conductively connected to the temperature sensor on the substrate. The two electrode pads each have one sensor component electrode pad and the other sensor component electrode pad, and one sensor component electrode pad is commonly connected to the other sensor component electrode pad. Are commonly connected, and the interval between one set of electrode pads is smaller than the interval between the other set of electrode pads, and the temperature sensor is mounted only on one set of sensor component electrode pads. This is a piezoelectric device.

  Examples of the sensor component serving as the temperature sensor include a thermistor and a diode. The diode may use a junction between the base and emitter of the transistor. These are hereinafter referred to as sensor parts.

  With the above configuration, it is possible to selectively mount sensor components of different sizes between the sensor component mounted on the one sensor component electrode pad and the sensor component mounted on the sensor component electrode pad. In addition, by mounting a large sensor component consisting of a thermistor, etc. using a joining material such as molten solder that has fluidity on the other electrode pad for the sensor component with a large separation width of the electrode pad, Reduced the risk of short circuit due to bonding material.

  Further, the sensor pad electrode pad of the other set may be made larger than the electrode pad for the sensor component of the one set described above, and the large sensor component can be stably mounted by such a configuration.

In addition, the thickness of one of the sensor component electrode pads described above may be larger at the tip than at the other.

By adopting the above configuration, it becomes easy to perform FCB (flip chip bonding) mounting of a small semiconductor sensor component.

  Moreover, the other electrode pad which opposes with respect to the one electrode pad for sensor components mentioned above may have a large area.

  By adopting the above configuration, even when sensor parts with a small mounting area are joined by FCB, etc., one joining point is provided on the side with a small tip end area, and a plurality of joining points are provided on the side with a large tip end area. It is possible to provide points, and it is possible to cope with the downsizing of sensor parts and to improve the stability of joining.

  Further, at least one of the tip parts of the sensor component electrode pads may be configured such that the width gradually decreases toward the opposing sensor component electrode pads.

  By adopting the above configuration, it is possible to improve the accuracy by image recognition when the sensor component is mounted on the sensor component electrode pad. In addition, when the sensor component is electrically joined at the same time and the joint between the sensor component and the substrate located below the sensor component is supplementarily reinforced with a resin material such as an underfill, a resin material is provided below the temperature sensor. Can be made to flow easily, and the bonding strength can be enhanced.

  The first cavity for storing the sensor component and the second cavity for storing the piezoelectric element are separate spaces, and the first cavity and the second cavity are in opposite directions with the substrate interposed therebetween. The center portion of the substrate of the second cavity may be curved in a concave shape.

  By adopting the above configuration, when the sensor component of the second cavity and the substrate are joined with a resin material, the resin material is prevented from accumulating at the bottom end of the second cavity S2, and the resin is formed under the sensor component. The material can be made to flow easily.

  The sensor component and the piezoelectric element may be housed in the same space.

  By adopting the above configuration, the sensor component can more accurately detect the actual temperature of the piezoelectric element.

  Further, the sensor component and the substrate may be supplementarily joined with a resin material.

  By adopting the above configuration, the efficiency of heat transfer from the package to the sensor component can be increased. It also plays a role of enhancing the bonding strength between the sensor component and the substrate.

  As described above, according to the piezoelectric device of the present invention, it is possible to selectively mount sensor parts having different sizes, and it is possible to obtain a piezoelectric device with a low risk of short circuit.

1 is a schematic cross-sectional view of a piezoelectric device showing a first embodiment of the present invention. 1 is a schematic plan view of a piezoelectric device showing a first embodiment of the present invention. (A) Case body (b) Piezoelectric element (c) Case body rear view The internal wiring figure of the electrode pad for sensor components in the 1st Embodiment of this invention. (A) Case body (b) Internal wiring diagram of sensor component electrode pads in the first embodiment of the present invention The schematic diagram which shows the 2nd Embodiment of this invention. (A) Typical sectional drawing of the piezoelectric device in 2nd Embodiment. (B) The top view which shows typically the case body of the piezoelectric device in 2nd Embodiment. (C) The top view which shows typically the back surface of the piezoelectric device in 2nd Embodiment. The typical sectional view of the piezoelectric device which a 3rd embodiment of the present invention shows. The typical sectional view of the piezoelectric device which shows the 4th embodiment of the present invention. The typical top view of the piezoelectric device which shows the 4th Embodiment of this invention. (A) Case body (b) Piezoelectric element (c) Case body rear view The internal wiring figure of the electrode pad for sensor components in the 4th Embodiment of this invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
A first embodiment according to the present invention will be described with reference to FIGS. 1, 2, and 3, taking a surface-mount type crystal vibrating device as an example.

  The piezoelectric vibration device includes a piezoelectric element 10 having a rectangular shape in plan view, a small sensor component 80, and a package 1 on which the piezoelectric element 10 and the small sensor component 80 are mounted. The package 1 has a case body 2 having a first cavity S1 having an open top, a second cavity S2 having an open bottom, a lid 4 that seals the top of the case body 2, and a metal ring 6 that serves as a joint portion thereof. , Composed of the joining member 3.

  The package 1 is a housing that can accommodate at least the piezoelectric element 10 and a small sensor component 80 serving as a temperature sensor. The storage location of the piezoelectric element 10 and the storage location of the small sensor component 80 are formed in opposite directions across the substrate 2-X, and each includes an upper storage location cavity S1 and a lower storage location cavity S2. The cavity S1 is sealed by the lid 4 after mounting the piezoelectric element 10, thereby preventing mechanical contact with the outside. The package 1 may be composed of a plurality of members. In the first embodiment, the package 1 includes a case body 2, a joining member 3, a lid body 4, and a metal ring 6.

  The case body 2 has the first cavity S1 and the second cavity S2 in which the piezoelectric element 10 and the small sensor component 80 can be accommodated, and each of these cavities is a rectangle having a long side and a short side in plan view. have. The first cavity S1 where the piezoelectric element 10 is mounted has piezoelectric element electrode pads 31 and 32 in the vicinity of one end of the long side, and the second cavity S2 where the small sensor component 80 is mounted. Has sensor component electrode pads 41, 42 and 43, 44. Further, the case body 2 has a bank portion 2-A on the outer periphery of the first cavity S1, and a bank portion upper surface 2-B on the upper surface of the bank portion 2-A. Ring 6 is joined. Moreover, the pillow 12 disposed on the vicinity of the other end of the long side of the case body 2 is a protruding portion extending in a band shape, and suppresses the deflection of the piezoelectric element 10 when subjected to an impact from the outside. It is for improving impact properties.

The structure of the case body 2 is formed by stacking a plurality of alumina ceramic insulating materials. In addition, wiring for electrical connection to the outside is formed inside the case body 2. In the first embodiment of the present invention, as shown in FIG. 2A, the piezoelectric element electrode pads 31 and 32 are biased to one side in the longitudinal direction of the bottom surface in the cavity S1 of the case body 2 and are arranged in the short side direction. Two pairs are formed. Further, as shown in FIG. 2A, the sensor component electrode pads 41, 42 and 43, 44 are formed on the bottom surface in the cavity S2 at both ends in the longitudinal direction, and two sets of two are formed. . The piezoelectric element electrode pads 31 and 32, the sensor component electrode pads 41 and 42, and the sensor component electrode pads 43 and 44 are formed by laminating a plated film of Ni and Au on a metallized film of W (tungsten). It is configured. The sensor component electrode pads 41, 42 are formed on one side of the bottom surface of the cavity S 2 in the longitudinal direction, and are mounting portions for the small sensor component 80. The sensor component electrode pads 41 and 42 are arranged in parallel with the opposite sides being not opposed to each other. The sensor component electrode pads 43 and 44 are formed on the other side of the bottom surface of the cavity S2 in the longitudinal direction. The sensor component electrode pads 43 and 44 are wider than the sensor component electrode pads 41 and 42, and the size of the electrode pads is also large. It has become. When the sensor component has a small size, the sensor component electrode pads 41 and 42 can be conductively bonded. When the sensor component has a large size, it can be mounted on the sensor component electrode pads 43 and 44. It is possible to set a wide range of sensor component sizes. The width between the sensor component electrode pads 41, 42 is preferably 0.01 mm or more in order to prevent a short circuit accident. In the present embodiment, the metallized film is made of W (tungsten), but may be formed of Mo (molybdenum), and alumina ceramic is used as the base material of the case body 2. Insulating material may be used.

Further, the case body 2 has through-hole vias and internal wiring, and the electrical wiring of the case body 2 is performed by these. The piezoelectric element electrode pads 31, 32, the sensor component electrode pads 41, 42 and the sensor component electrode pads 43, 44 are led out to the outside by internal wiring and through-hole vias. Through-hole vias connect the wirings by filling the through-holes with a conductive material. Examples of the conductive material used for the through-hole via include metals such as W and Mo. The internal wiring is connected to terminal electrodes K1, K2, K3, K4 made of a metal film in a castellation provided at the corner of the outer periphery of the case body 2, and the external connection terminals 51, 52, 53, 54 on the respective back surfaces. Is electrically connected. Note that the terminal electrode and the external connection terminal are also configured by laminating a Ni or Au plating film on a metallized film of W or Mo. The piezoelectric element electrode pad 31 is connected to the terminal electrode K3 by internal wiring, and the piezoelectric element electrode pad 32 is connected to the terminal electrode K2. As shown in FIG. 3, the sensor component electrode pad 41 and the sensor component electrode pad 43 are connected to the internal wiring 45 and connected to the terminal electrode K1. On the other hand, the sensor component electrode pad 42 and the sensor component electrode pad 44 are connected to the internal wiring 46 and are connected to the terminal electrode K4. With the above configuration, the piezoelectric element electrode pads 31 and 32 are electrically connected to the external connection terminals 53 and 52, respectively, and the sensor component electrode pad 41 and the sensor component electrode pad 43 are connected to the external connection terminal 51. The pad 42 and the sensor component electrode pad 44 are electrically connected to the external connection terminal 54.

  Next, an example of a method for producing the case body 2 will be given. In the case of an alumina ceramic, an appropriate organic solvent or the like is added to a predetermined ceramic material powder and mixed to obtain a ceramic green sheet. Conductive paste that becomes electrode pads for piezoelectric elements 31, 32, electrode pads for sensor parts 41, 42, 43, 44, external connection terminals 51, 52, 53, 54, etc. in a predetermined pattern on the surface of the ceramic green sheet In addition to coating, apply conductive paste (metallizing paste) as a via conductive material in the through-hole previously drilled in the ceramic green sheet, stack multiple sheets, press mold, and fire at high temperature It is manufactured by doing. At the time of this lamination, the cavity S1 and the cavity S2 can be formed by using the cavity S1 and several layers of ceramic green sheets corresponding to the cavity S having a hole in the center.

The metal ring 6 has a frame shape with the center punched out and is made of a Kovar material (Fe—Ni—Co alloy). Further, as another example of the metal ring 6, it may be made of a metal such as 42 alloy material (Fe—Ni alloy). When the metal ring 6 is used to form the side wall of the package 1, a metallized film (not shown) made of W is provided on the portion of the upper surface of the case body 2 where the metal ring 6 is disposed, and silver brazing is applied to the upper part thereof. A metal ring 6 made of a material is joined. On the surface of the metal ring 6, a plating film made of Ni or Au is laminated. The metallized film may be made of Mo (molybdenum).

  The lid 4 seals the upper opening of the case body 2 and is made of rectangular Kovar (Fe—Ni—Co alloy) when viewed in a plan view. Further, as another example of the metal ring 6, it may be made of a metal such as 42 alloy material (Fe—Ni alloy). The Kovar that forms the lid 4 has a front surface covered with Ni. The lid body 4 is sized to cover the cavity S1 of the case body 2, and constitutes the package 1 by adhering to the upper surface 2-B of the bank portion, and defines the cavity S1 that is a space in which the piezoelectric element 10 and the sensor component 80 operate. It is hermetically sealed in an inert gas atmosphere or a vacuum atmosphere. In this embodiment, the cover 4 is made of Kovar (Fe—Ni—Co alloy), but other examples include glass, quartz, 42 alloy (Fe—Ni alloy), ceramic, phosphor bronze, etc. A metal may be used, and the shape is not particularly limited as long as the case body 2 can be sealed to form a sealed space. Further, the bonding material may be different depending on the material.

  Next, a method for adhering the metal ring 6 melted and bonded to the lid 4 and the case body 2 will be described. The surface of the lid 4 is covered with Ni, and the lid 4 is disposed on the Au plating film of the metal ring 6. By energizing the roller 4 of the parallel seam welding machine while pressing the ridge line portion of the lid 4 and running, the Ni surface of the contact of the lid 4 and the Ni surface below the Au surface of the metal ring 6 are melted. As a joining member, hermetic sealing is performed. In the present embodiment, the lid 4 is covered with Ni, but the present invention is not limited to this. Moreover, although the sealing method in this embodiment is seam sealing, the joining member 3 is different depending on the material of the case body 2 and the lid body 4, and the bonding method is also different. As other examples, a welding method such as electron beam welding, or a method using a bonding material such as metal brazing sealing, low melting point glass sealing, or resin sealing may be used.

  The piezoelectric element 10 is disposed in the cavity S1 of the package 1. The piezoelectric element 10 uses a rectangular AT-cut quartz plate having a long side and a short side, and electrodes are formed facing the front and back surfaces. The electrode is formed by forming a Cr film on the upper surface of a quartz plate and laminating a film made of Au or Ag on the upper surface. In addition, the piezoelectric vibrator 10 in this embodiment is an AT-cut quartz diaphragm, but as another example, the piezoelectric vibrator 10 may be formed of a piezoelectric material such as lithium tantalate, lithium niobate, or piezoelectric ceramic. In such a case, an SC cut vibrator, a tuning fork vibrator, a double tuning fork vibrator, or the like can be used, and the shape of the piezoelectric element 10 is not limited.

  As shown in FIG. 2B, the electrode of the piezoelectric element 10 has a rectangular excitation electrode 70 having a long side and a short side opposed to each other at the center, and the corner of one short side from the excitation electrode 70. And two lead electrodes 71 and 72 provided in pairs on one of the short sides. The lead electrodes 71 and 72 are portions to be bonded to the piezoelectric element electrode pads 31 and 32 of the case body 2, respectively.

  The conductive adhesive 11 is in the cavity S1, and is used to fix the piezoelectric element 10 to the case body 2 on one short side of the case body 2 and to conduct the same. The lead electrodes 71 and 72 of the piezoelectric element 10 are bonded onto the piezoelectric element electrode pads 31 and 32 of the case body 2, respectively. Thereby, electrical connection is made with the excitation electrode 70 formed on the piezoelectric element 10. The conductive adhesive 11 contains conductive powder as a conductive filler in a binder such as a silicone resin. This conductive powder is used in combination of Pd and Ag. The conductive powder in this example is Pd, Ag, but as another example, any one of Al, Mo (molybdenum), W (tungsten), Pt, Ti, Ni, NiFe, or any combination thereof is used. What is included may be used and a metal bump etc. may be used instead of the conductive adhesive 11.

  The small sensor component 80 is a temperature sensor disposed in the second cavity S2, and uses a junction between the base and emitter of a transistor as a substitute for a diode. Since the transistor can be manufactured using a silicon wafer, it has an advantage that it can be easily reduced in size, and is smaller than the sensor component 90 formed of a thermistor or the like normally used as a temperature sensor. A transistor has three terminals: a base, an emitter, and a collector. Usually, the amplification action generated in the emitter current is utilized by applying a forward voltage between the base and the emitter and a reverse voltage between the collector and the base. The transistor of the present invention is used as a temperature sensor by connecting only two terminals between the base and the emitter, passing a constant current, and using a change in voltage caused by a temperature change. The external input terminal and the external output terminal (not shown) of the small sensor component 80 are fixed to the sensor component electrode pads 41 and 42 provided on the case body 2 by the bonding material 21 to be electrically connected, thereby obtaining temperature data. A signal is output outside the package. Further, the bonding strength is increased by auxiliary bonding between the small sensor component 80 and the substrate 2-X with a resin material. Although the small sensor component 80 in the present embodiment is a temperature sensor composed of a transistor, a thermistor or a diode may be used as the temperature sensor.

  The bonding material 21 is used to fix the small sensor component 80 in the second cavity S2 and to connect the external connection terminal of the small sensor component 80 and the electrode pads 41 and 42 for the sensor component. It depends on. When a miniaturized transistor made of a silicon wafer is mounted in the proximity portion, it is made of FCB (flip chip bonding). Other examples include soldering and electromechanical joining with a conductive adhesive.

A method for manufacturing the piezoelectric device of the first embodiment composed of the above components will be described. The conductive adhesive 11 is applied to the piezoelectric element electrode pads 31 and 32 in the first cavity S1, and the piezoelectric element electrode pad 31 and 32 and the lead electrodes 71 and 72 correspond to the piezoelectric element 10 on the conductive adhesive 11, respectively. Then, the product is put into a heating furnace and the conductive adhesive 11 is cured. Next, the frequency is adjusted by increasing or decreasing the film thickness of the product electrode, and the product is placed in an annealing furnace and heated again. The lid 4 is disposed on the first cavity S1 in a vacuum atmosphere and joined by seam welding. Specifically, when the roller electrode of the seam welder presses the ridge line portion of the lid body 4 while energizing and running, the Ni surface of the contact point of the lid body 4 and the Ni surface under the Au surface of the metal ring 6 are melted. , Ni serves as a joining member, and hermetic sealing is performed in a vacuum. After sealing, the small sensor 80 is fixed to the sensor component electrode pads 41 and 42 in the second cavity S2 by using the bonding material 21 through a heat treatment process such as aging and an inspection process. Thereafter, the resin material 22 is injected between the small sensor 80 and the substrate 2-X, and a final product inspection is performed through a resin material drying process.

  In the first embodiment of the present invention, electrode pads 41 and 42 for sensor parts having a small electrode pad and a narrow width between the pads, and electrodes for a sensor part having a large electrode pad and a wide width between the pads are shown. Pads 43 and 44 are provided. Therefore, it is possible to mount a small sensor component 80 made of a miniaturized transistor or the like on the sensor component electrode pads 41 and 42 between the pads. Since the sensor component electrode pads 41 and 42 have a smaller electrode pad size than the sensor component electrode pads 43 and 44, the opposing regions are smaller than the sensor component electrode pads 43 and 44. As a result, the risk of a short circuit (short circuit) is less than when the entire sensor component electrode pads 43 and 44 are brought close to each other.

  Next, a modified example of the sensor component electrode pad according to the present invention will be described with reference to FIG.

4 is different from FIG. 2 in that one set of sensor component electrode pads 41a, 42a and the other set of sensor component electrode pads 43a, 44a are connected to through-hole vias 411, 11 at the bottom surface of the second cavity S2. Internal wiring is performed using 421,431,441. Further, the tip parts 401a and 402a, which are the mounting parts of the small sensor parts 80 of the electrode pads 41a and 42a for sensor parts, have a thickness larger than that outside the mounting part.

  The case body 2 is formed by laminating alumina ceramic as in the first embodiment of the present invention, and has the same function, but the sensor component electrode pads 41a, 42a, 43a, 44a are the same as those of the package 1. Through hole vias 411, 421, 431, and 441 are provided at one end of each of the sensor component electrode pads 41a, 42a, 43a, and 44a, and are not drawn into the ceramic laminated portion on the short side. It is connected. The sensor component electrode pads 41a and 43a drawn into the ceramic laminate by the through-hole vias 411 and 431 are connected to the internal wiring 451 and are connected to the external connection terminal 51 through the terminal electrode K1 as in the first embodiment. Has been. In addition, the sensor component electrode pads 42a and 44a drawn into the laminate by the through-hole vias 421 and 441 are also connected to the internal wiring 461 and to the external connection terminal 54 through the terminal electrode K4 as in the first embodiment. Connected with.

  The sensor component 90 in the present modification is a thermistor, and its size is larger than the small sensor component 80 used in the first embodiment of the present invention. In addition to the changes, the case body 2, the joining member 3, the lid body 4, the piezoelectric element 10, and the conductive adhesive 11 constituting the package 1 used in the above embodiment are the first embodiment of the present invention. It has the materials and functions used in the form, and its shape is also correct.

  The effect of drawing the wiring into the ceramic laminate by the through-hole vias 411, 421, 431, and 441, which are modifications of the first embodiment, and the thicknesses of the tip portions 401a and 402a of the sensor component electrode pads 41a and 42a. The effect of being larger than other parts will be explained.

  In the first embodiment described above, the inner wall upper end outer frame of the second cavity S2 and the external connection terminals 51, 52, 53, and 54 are close to each other as the package size is reduced. For this reason, the solder melted when the sensor component 90 is soldered in the second cavity S2 flows along the outer wall from the sensor component electrode pads 43 and 44 in the second cavity S2, and the bottom surface of the case body 2 May reach the external connection terminals 51 to 54 and short circuit (short circuit). In the modification of the first embodiment of the present invention, since the sensor component electrode pads 43a and 44a are not in contact with the inner wall of the cavity S2, it is possible to prevent the solder from flowing into the external connection terminals.

  Further, when it is selected that the small sensor component is mounted on the sensor component electrode pads 41a and 42a, the thickness of the tip portions 401a and 402a of the sensor component electrode pad is larger than the portion other than the mounting portion. It is possible to facilitate FCB (flip chip bonding) mounting of components.

  Next, a second embodiment of the present invention will be described with reference to FIG.

  In this example, the package 1 is configured differently from the first embodiment, and the shape of the facing parts of the sensor component electrode pads 41b and 42b is different. The tip portion 401b, which is the opposite portion of the sensor component electrode pad 41b, has a semicircular curvature. The front end portion 402b, which is the opposite portion of the sensor component electrode pad 42b, is T-shaped to ensure a wide bonding area for the sensor component.

  The package 1 is a housing that can accommodate at least the piezoelectric element 10 and a small sensor component 80 serving as a temperature sensor. The storage location of the piezoelectric element 10 and the storage location of the small sensor component 80 are formed in opposite directions across the substrate 2-X. From the first cavity S1 and the lower storage location second cavity S2, respectively. Become. The first cavity S1 is sealed by the lid body 4 after mounting the piezoelectric element 10, thereby preventing mechanical contact with the outside. The package 1 may be composed of a plurality of members. In the piezoelectric device according to the first embodiment of the present invention, the package 1 includes a case body 2, a joining member 3, and a lid body 4.

  The case body 2 has a first cavity S1 and a second cavity S2 in which the piezoelectric element 10 and the small sensor component 80 can be accommodated, and has a shape in which both upper and lower sides are opened. A rectangle with a long side and a short side. The first cavity S1 where the piezoelectric element 10 is mounted has the piezoelectric element electrode pads 31 and 32, and the second cavity S2 where the small sensor component 80 is mounted has the sensor component electrode pads 41b and 42b. , 43b, 44b. Further, the case body 2 has a bank portion 2-A on the outer periphery of the first cavity S1, and a bank portion upper surface 2-B on the upper surface of the bank portion 2-A. The body 4 is joined.

  The case body 2 is formed by laminating alumina ceramic as in the first embodiment of the present invention, and has the same function, but the sensor component electrode pad 41b and the sensor component electrode pad 42b face each other. The sides of the sensor component electrode pad 41b are semi-circular with the width gradually decreasing toward the opposite sensor component electrode pad 41b. The tip end portion 402b of the electrode pad 42b is formed to have a larger area than the other. In addition, the connection destination by the internal wiring is the same as that of the first embodiment of the present invention.

  The lid 4 is made of Kovar as a base material, and the upper surface is covered with Ni. Further, the lower surface, which is a bonding surface, is covered with Cu serving as a buffer material, and has a four-layer structure in which a plate-like Ag brazing is disposed below.

Next, a method for bonding the lid body 4 and the case body 2 will be described. A thick metallized film made of W (tungsten) or the like is provided in advance on the upper surface 2-B of the bank portion of the case body 2, and a plated film made of Ni, Au, or the like is disposed thereon. The contact point Ag of the lid 4 is obtained by running electricity while pressing the ridge line portion of the lid 4 with the energizing roller electrode of the seam welding machine in a state where the Ag brazing of the lid 4 is in contact with the upper surface 2-B of the bank portion. The Au in the case body 2 is melted and hermetically sealed.

  Further, except for the changes in the second embodiment of the present invention, the case body 2, the joining member 3, the lid body 4, the piezoelectric element 10, and the conductive adhesive 11 constituting the package 1 used in the above-described embodiment. The small sensor component 80 has the materials and functions used in the first embodiment of the present invention, and the shape thereof is also appropriate.

The effect by the shape change of the front-end | tip parts 401b and 402b of the electrode pads 41b and 42b for sensor components which are the said 2nd Embodiment is demonstrated. By forming the tip 401b of the sensor component electrode pad 41b in a semicircular shape, it is possible to improve the accuracy of image recognition when the small sensor component 80 is mounted on the sensor component electrode pads 41b and 42b. In the case where the small sensor component 80 is electrically bonded at the same time, and then the small sensor component 80 and the substrate 2-X positioned below the sensor component are supplementarily reinforced with a resin material 22 such as an underfill, The resin material can easily flow into the lower part of the temperature sensor, and the bonding strength can be enhanced. In addition, when the tip part 402b of the sensor component electrode pad 42b has a larger area than the other tip part 401b, the small sensor part 80 having a small mounting area is joined by FCB (flip chip bonding) or the like. In addition, it is possible to provide one joint point on the side where the tip end area is small and to provide a plurality of joint points on the side where the tip end area is large, which is compatible with the small sensor part 80 and increases the stability of the joint. Can do.

  Next, a third embodiment according to the present invention will be described with reference to FIG. 6 by taking a surface-mounted crystal oscillator as an example.

  In the third embodiment of the present invention, the shape of the second cavity S2 in the first embodiment is changed. The second cavity S2 has a side wall and a bottom surface, and the bottom surface corresponds to the surface of the substrate 2-X. Moreover, it is the form which the center part is curving concavely rather than the edge part of the bottom face of a 2nd cavity.

  Except for the change of the case body 2 in the third embodiment, the case body 2, the joining member 3, the lid body 4 and the piezoelectric element 10, the conductive adhesive 11, which constitute the package 1 used in the above-described embodiment, The small sensor component 80 has the materials and functions used in the first embodiment of the present invention, and the shape thereof is also appropriate.

  By adopting the third embodiment, when the sensor component 80 is mounted in the second cavity S2, and a resin material is poured into the lower portion of the small sensor component 80 for strengthening the connection and protecting the electrode pad portion. In addition, it can be made easier to flow toward the center of the substrate 2-X.

  Next, a fourth embodiment of the present invention will be described with reference to FIGS. 7, 8, and 9 by taking a surface mount type crystal oscillator as an example.

  The fourth embodiment according to the present invention is an integrated package in which the cavity of the package 1 is only the cavity S1, the piezoelectric element 10 and the small sensor component 80 are mounted in the cavity S1, and a method for holding the piezoelectric element 10 is provided. It is a form in which both sides are held. The tip part 402c of the sensor component electrode pad 42c has a smaller area than the other tip part 401c. The sensor component electrode pads 43c and 44c do not reach the inner wall as in the modification of the first embodiment.

The case body 2 has the above-described cavity S1 and recess S3 that can accommodate the piezoelectric element 10 and the small sensor component 80, and has a container-like configuration with an open top, and has a long side and a short side in plan view. It has a rectangle. Further, the case body 2 has a bank portion 2-A on the outer periphery of the cavity S1, has a bank surface 2B on the upper surface of the bank portion 2-A, and a part of the upper surface of the bank portion and the lid body 4 are Be joined.

  The structure of the case body 2 is formed by stacking a plurality of alumina ceramic insulating materials. Further, the case body 2 has a step on the inner bottom surface, and a wiring that is electrically connected to the outside is formed inside the case body 2. In the first embodiment of the present invention, two pairs of piezoelectric element electrode pads 31 and 32 are formed diagonally on both sides of the bottom surface in the cavity S1 of the case body 2 as shown in FIG. Further, as shown in FIG. 2 (a), the sensor component electrode pads 41c, 42c and 43c, 44c are biased to both ends in the longitudinal direction on the bottom surface in the cavity S1, and two sets of two are formed. . The piezoelectric element electrode pads 31 and 32 and the sensor component electrode pads 41c and 42c are formed by laminating Ni and Au plating films on a metallized film of W (tungsten). The sensor component electrode pads 41 c and 42 c are formed on one side in the longitudinal direction of the bottom surface of the cavity S 1, and are mounting portions for the small sensor component 80. The sensor component electrode pads 41c and 42c are arranged so that the sides facing each other in parallel are directly opposed. The sensor component electrode pads 43c and 44c are formed on the other side of the bottom surface of the cavity S1 in the longitudinal direction. The sensor component electrode pads 43c and 44c are wider than the sensor component electrode pads 41c and 42c. It has become. When the sensor component has a small size, the sensor component electrode pads 41c and 42c can be conductively joined. When the sensor component has a large size, it can be mounted on the sensor component electrode pads 43c and 44c. It is possible to set a wide range of sensor component sizes. The width between the sensor component electrode pads 41c, 42c is preferably 0.01 mm or more in order to prevent a short circuit accident. In the present embodiment, alumina ceramic is used as the base material of the case body 2, but as another example, an insulating material such as glass ceramic or glass may be used.

The internal wiring in the fourth embodiment of the present invention will be described with reference to FIG. The case body 2 has through-hole vias and internal wiring, and the electrical wiring of the case body 2 is performed by these. The piezoelectric element electrode pads 31, 32 and the sensor component electrode pads 41c, 42c, 43c, 44c are led out to the outside by through-hole vias and internal wiring. Through-hole vias connect the wirings by filling the through-holes with a conductive material. Examples of the conductive material used for the through-hole via include metals such as W (tungsten) and Mo (molybdenum). The internal wiring is connected to terminal electrodes K1, K2, K3, K4 made of a metal film in a castellation provided at the corner of the outer periphery of the case body 2, and the external connection terminals 51, 52, 53, 54 on the respective back surfaces. Is electrically connected. Note that the terminal electrode and the external connection terminal are also configured by laminating a Ni or Au plating film on a metallized film of W or Mo. The piezoelectric element electrode pad 31 is connected to the terminal electrode K2 through a through-hole via and internal wiring, and the piezoelectric element electrode pad 32 is connected to the terminal electrode K3. As shown in FIG. 9, the sensor component electrode pad 41c and the sensor component electrode pad 43c are connected to the internal wiring 45c and connected to the terminal electrode K1. On the other hand, the sensor component electrode pad 42c and the sensor component electrode pad 44c are connected to the internal wiring 46c and connected to the terminal electrode K4. With the above configuration, the piezoelectric element electrode pads 31 and 32 are electrically connected to the external connection terminals 53 and 52, respectively, and the sensor component electrode pad 41 c and the sensor component electrode pad 43 c are connected to the external connection terminal 51. The pad 42 c and the sensor component electrode pad 44 c are electrically connected to the external connection terminal 54.

  The piezoelectric vibrator 10 has a function similar to that of the first and second embodiments of the present invention, and is a rectangular AT-cut crystal diaphragm. As shown in FIG. 8B, the electrode has a rectangular excitation electrode 70 facing the front and back in the center, and lead electrodes 71 and 72 with the electrodes extended on the left and right diagonal lines.

  The conductive adhesive 11 has the same material and function as those of the first and second embodiments of the present invention, and the piezoelectric element 10 is fixed to the case body 2 on the small sensor component 80 in the cavity S1. It is for conducting. In this embodiment, the conductive adhesive 11 is positioned on the opposite sides of the case body 2 on the diagonal lines on the piezoelectric element electrode pads 31 and 32 in FIG. Take.

  Except for the changes in the fourth embodiment, the case body 2, the joining member 3, the lid body 4, the piezoelectric element 10, the conductive adhesive 11, and the small sensor component 80 that constitute the package 1 used in the above embodiment. Has the materials and functions used in the first embodiment of the present invention, and the shape thereof is also in order.

  In addition, since the piezoelectric element 10 and the small sensor component 80 are mounted in the same space, the temperature difference between the piezoelectric element 10 and the small sensor component 80 is reduced, and the piezoelectric element 10 can output more accurate temperature data of the piezoelectric element 10. You can get a device. Also, by holding the piezoelectric element 10 on both sides, the piezoelectric element does not shake greatly even when a large impact is applied to the package 1, and does not come into contact with the piezoelectric element even when the package 1 is deformed. It can be said that the piezoelectric device has excellent impact resistance. For this reason, it is effective in an in-vehicle piezoelectric device where an impact is expected. In the third embodiment, both ends of the long side of the piezoelectric element 10 are held, but a configuration may be adopted in which the center part of each short side is held instead of the diagonal. Further, by making the tip part 402c of the sensor component electrode pad 42c smaller than the other tip part 401c facing each other, the opposing region of the tip part can be reduced, and the risk of short circuit can be reduced. The accuracy by image recognition when mounting the component 80 on the sensor component electrode pads 41c and 42c can be improved.

  As described above, a plurality of examples are given in the embodiment and the modified examples, but these can be combined with each other and applied to the piezoelectric device of the embodiment. Thereby, the synergistic effect by a combination can be acquired.

  It should be noted that the present invention can be implemented in various other forms without departing from the spirit, gist, or main features. For this reason, the above-described embodiment is merely an example in all respects and is not construed in a limited manner. The scope of the present invention is indicated by the scope of claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  Applicable for mass production of piezoelectric devices or other sensor parts.

DESCRIPTION OF SYMBOLS 1 Package 2 Case body 3 Joining member 4 Lid body 6 Metal ring 10 Piezoelectric element 11 Conductive adhesive 21 Joining material 22 Resin material 31, 32 Electrode pad 41, 42, 43, 44 for piezoelectric elements 401, Electrode pad for sensor components 402 Tip portion 411, 421, 431, 441 Through-hole via 45, 46, 451, 461 Internal wiring 51, 52, 53, 54 External connection terminal 70 Excitation electrode 71, 72 Lead electrode 80 Small sensor component 90 Sensor component S1, S2 Cavity 2-A Embankment 2-B Embankment upper surface 2-X Substrate K1, K2, K3, K4 Terminal electrode

Claims (5)

A piezoelectric device in which a piezoelectric element on which an excitation electrode is formed and a temperature sensor are housed in a package,
The package has two sets of electrode pads for sensor components that are conductively connected to the substrate and sensor components for sensing temperature on the substrate,
The two sets of sensor component electrode pads each have one sensor component electrode pad and the other sensor component electrode pad,
The electrode pads for the one sensor component are connected in common,
The other sensor component electrode pads are connected in common,
The spacing between one set of electrode pads is smaller than the spacing between the other set of electrode pads,
A piezoelectric device characterized in that a temperature sensor is mounted only on one set of sensor component electrode pads. The package has a first cavity and a second cavity which are separate spaces, respectively, and the piezoelectric element is housed in the first cavity and the sensor component is housed in the second cavity. 1. The piezoelectric device according to 1. The first cavity for housing the piezoelectric element and the second cavity for housing the temperature sensor are formed in opposite directions with the substrate interposed therebetween, and the central portion of the substrate of the second cavity is concave. The piezoelectric device according to claim 2, wherein the piezoelectric device is curved. The piezoelectric device according to claim 1, wherein the temperature sensor and the piezoelectric element are accommodated in the same space. The piezoelectric device according to claim 1, wherein the temperature sensor and the substrate are bonded with a resin material.

Images