JP2017046341A - Piezoelectric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact piezoelectric oscillator with high connection reliability.SOLUTION: A quartz oscillator 1 is a piezoelectric oscillator formed by joining a bottom electrode 8 onto a junction electrode 10 through a joint material 14 so that a first container 4 covers a recess C2 of a second container 3. In a state after the first container 4 and the second container 3 are joined, part of the bottom electrode 8 is, in transparent plan view, positioned above the recess C2 beyond an inner circumferential edge of the junction electrode 10 and vias V1 to V4, electrically connecting the junction electrode 10 and a pad for mounting an oscillation circuit element, are exposed at an inner wall surface of a side wall of the second container.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a piezoelectric device in which a piezoelectric vibrator is bonded to and integrated with an upper part of a container containing electronic component elements.

  As a simple and low-cost piezoelectric device, a piezoelectric vibrator formed by hermetically sealing a container containing a piezoelectric vibrating piece with a lid on the upper part of a container containing an oscillation circuit element is conductively joined to form two layers. A so-called two-story piezoelectric oscillator is known. A piezoelectric oscillator having such a structure is disclosed in Patent Document 1, for example.

  After the piezoelectric oscillator is mounted on the external substrate with solder or the like, stress generated from the external substrate due to thermal factors or the like is transmitted to the piezoelectric oscillator. For example, in the case of the piezoelectric oscillator having the two-story structure described above, the stress is transmitted to the lower container in which the oscillation circuit element corresponding to the first floor part is accommodated, and the upper container (piezoelectric vibrator) joined to the lower container. It will be transmitted to. The propagation of the stress may cause a crack in the joint between the lower container and the upper container, and sufficient joint reliability may not be obtained. Further, the upper container is deflected by the propagation of the stress generated from the external substrate to the lower container, and the stress is transmitted to the piezoelectric vibrating piece joined to the upper container. As a result, the oscillation frequency may vary.

  For example, Patent Document 2 discloses a piezoelectric oscillator that has been devised to increase the bonding strength between the lower container and the upper container. In the crystal oscillator in Patent Document 2, a joining terminal having a planar outer shape smaller than the vibrator terminal is formed from the upper surface of the frame wall of the lower container to the inner peripheral surface. By forming the joining terminal in such a form, a solder fillet is formed on the inner peripheral surface of the frame wall to increase the joining strength.

  However, since the junction terminal in Patent Document 2 is formed across the inner peripheral surface (inner wall surface) of the frame wall, when the crystal oscillator becomes smaller, the electrode pattern on the inner bottom surface of the recess that accommodates the IC chip The risk of a short circuit increases. In addition, when cleaning the plasma by irradiating the plasma vertically from above the opening surface of the mounting substrate (lower container) for surface cleaning of the electrode pattern on the inner bottom surface of the recess, the junction terminal on the inner wall surface of the frame wall May be reduced. As a result, the junction terminal having the intended shape cannot be obtained, and the joining reliability may be reduced. Moreover, if the junction terminal is formed across the inner wall surfaces of the adjacent frame walls, the amount of metal used increases, leading to an increase in cost.

Japanese Patent No. 2974622 JP 2006-50282 A

  The present invention has been made in view of the above points, and an object of the present invention is to provide a piezoelectric device that can be miniaturized and has high bonding reliability.

  In order to achieve the above object, according to the present invention, the first container includes a mounting electrode on which the piezoelectric vibrating piece is mounted, and a bottom electrode led out from the mounting electrode to the outer bottom surface of the container. A concave portion in which the electronic component element is mounted, an electronic component element mounting pad provided on the inner bottom surface of the concave portion, a side wall surrounding the concave portion, and a joint provided on the top surface of the side wall and corresponding to the bottom electrode. An electrode and a via that is exposed on the inner wall surface of the side wall and electrically connects the bonding electrode and the electronic component element mounting pad, so that the first container covers the recess of the second container, The bottom electrode is bonded onto the bonding electrode via a bonding material, and in a state after the bonding, a part of the bottom electrode is located above the concave portion beyond the inner peripheral edge of the bonding electrode in plan view transmission, Part of the bottom electrode located above the recess Has a piezoelectric device fillets of the bonding material is formed to extend et the via.

  According to the said invention, the joint strength of a 1st container and a 2nd container can be improved, respond | corresponding to size reduction of a piezoelectric device. This is because the via that electrically connects the bonding electrode and the electronic component element mounting pad is exposed on the inner wall surface of the side wall of the second container. This is because a fillet (meniscus) can be formed. Specifically, since the fillet of the bonding material is formed from the inner peripheral edge located above the concave portion of the bottom electrode to the via, the bonding strength between the first container and the second container can be improved. Further, since the space can be saved as compared with the case where the conductor is formed in a planar shape on the inner wall surface of the side wall, a short circuit between the bonding electrode and the electrode pattern on the inner bottom surface of the recess can be prevented. Further, the amount of metal used can be reduced as compared with the case where the bonding electrode is formed on two surfaces so as to extend from the upper surface of the side wall to the inner wall surface of the side wall.

  Further, according to the above configuration, since the electrical connection between the bonding electrode of the second container and the electronic component element mounting pad is performed by the via, the electrons are transferred from the bonding electrode on the upper surface of the side wall via the outer surface of the second container. There is no need to route to the component element mounting pads. That is, since the conductor is not exposed to the outside of the second container, the solder melted when the piezoelectric device is joined to the external substrate with the solder crawls up to the conductor exposed to the outside of the second container, and other electrodes There is no risk of short circuiting due to contact.

  The first container includes a joint portion where the piezoelectric vibrating piece is cantilevered to the mounting electrode, and the upper surface of the side wall of the second container has a substantially rectangular frame shape in plan view, and the pair of the side walls face each other. It is composed of a pair of long sides opposed to the short side, and the vias are in a side wall of either the pair of long sides or the pair of short sides that do not overlap the joint in a plan view transmission. It may be formed only on the wall surface. In the case of such a via arrangement, the TTFF characteristic (Time To First Fix) can be improved. This is due to the following reason.

  One of the factors affecting the TTFF characteristic is a stress acting on the piezoelectric vibrating piece. In the case of the above configuration, since no via is arranged below the joint portion, a fillet of the joint material is formed on the long side portion or the short side portion that overlaps the joint portion in a plan view transmission of the side wall of the second container. Not. This makes it difficult for contraction stress acting on the fillet of the bonding material to be transmitted to the piezoelectric vibrating piece. As described above, the stress transmitted to the piezoelectric vibrating piece is alleviated, so that the fluctuation of the oscillation frequency is suppressed and the TTFF characteristics can be improved.

  In order to achieve the above object, the electronic component element is an oscillation circuit element, and the second container is exposed to the oscillation circuit element mounting pad provided on the inner bottom surface of the recess and the inner wall surface of the side wall. The piezoelectric oscillator may include a via that electrically connects the bonding electrode and the oscillation circuit element mounting pad.

  In order to achieve the above object, the first container has a rectangular parallelepiped shape, and each of the four ridges on the outer surface of the container is cut out in the thickness direction of the container up to the outer bottom surface of the first container. In addition, a castellation in which a conductor is attached to the inner wall surface thereof is formed, and the bottom electrode is formed at four corners on the outer bottom surface of the first container through a lead-out portion continuous with the castellation. In a state where the container and the second container are joined, the lead-out portion may protrude outward from the outer peripheral edge of the joint electrode, and the joint material may extend to the bottom electrode and at least the lead-out portion.

  According to the said invention, joint strength can be improved more. This is because, in the state where the first container and the second container are joined, the lead-out part protrudes outward with respect to the outer peripheral edge of the joining electrode, so that a fillet of the joining material is also formed on the lead-out part. This is because the bonding strength is improved. Note that the bonding material may extend to not only the bottom electrode and the lead portion but also a castellation continuous with the lead portion. That is, the first container and the second container can be bonded more firmly by forming the fillet of the bonding material also in the castellation. Such a bonding form is suitable for in-vehicle applications that require high bonding reliability and when the piezoelectric device is further downsized. In addition, when the fillet of the bonding material is formed in the castellation, it is possible to confirm the rising state of the bonding material from the outside of the piezoelectric device.

  As described above, it is possible to provide a piezoelectric device that can cope with downsizing and has high bonding reliability.

1 is a schematic cross-sectional view of a crystal oscillator according to an embodiment of the present invention. The bottom face schematic diagram of the 1st container of the crystal oscillator concerning the embodiment of the present invention. The upper surface schematic diagram of the 2nd container of the crystal oscillator which concerns on embodiment of this invention. The bottom face schematic diagram of the crystal oscillator concerning the embodiment of the present invention Top surface transmission diagram of a crystal oscillator according to an embodiment of the present invention 1 is a schematic cross-sectional view of a crystal oscillator according to an embodiment of the present invention. The partial side view of the crystal oscillator concerning the embodiment of the present invention Top surface transmission diagram of a crystal oscillator according to an embodiment of the present invention The upper surface schematic diagram of the 2nd container which concerns on the modification of embodiment of this invention. The upper surface schematic diagram of the 2nd container which concerns on the other modification of embodiment of this invention. The upper surface schematic diagram of the 2nd container which concerns on the other modification of embodiment of this invention. Upper surface transmission diagram of a crystal oscillator according to another modification of the embodiment of the present invention

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 6, taking a crystal oscillator (TCXO) having a temperature compensation function as an example of a piezoelectric device. FIG. 1 is a schematic cross-sectional view taken along the line AA in FIG. 3 in a state where a crystal resonator is mounted on the upper portion of the second container.

  FIG. 1 is a schematic sectional view of a crystal oscillator according to an embodiment of the present invention. The crystal oscillator 1 has a substantially rectangular parallelepiped shape as a whole, and has a substantially rectangular shape in plan view. In the present embodiment, the external dimensions of the crystal oscillator 1 in plan view are 1.65 mm for the long side and 1.25 mm for the short side. The external dimensions in plan view of the crystal oscillator described above are merely examples, and the present invention can be applied to package sizes other than the external dimensions.

  The crystal oscillator 1 has a so-called “two-story structure” in which the crystal resonator 2 is conductively bonded to the upper portion of the second container 3 via a bonding material (solder). In the crystal oscillator 1, four external connection terminals 12a, 12b, 12c, and 12d provided at the four corners of the outer bottom surface 301 of the second container are joined to an external substrate via solder or the like. Hereinafter, a description will be given of the crystal oscillator constituting the crystal oscillator and the second container.

  The crystal unit 2 is a surface-mount type piezoelectric unit composed of a rectangular parallelepiped package. The crystal resonator 2 includes a crystal resonator element 7, a first container 4, and a lid 9 as main constituent members. Hereinafter, an outline of the crystal unit 2 will be described with reference to FIGS.

  A crystal resonator element 7 shown in FIG. 1 is a piezoelectric element having a rectangular shape in plan view in which various electrodes are formed on the front and back main surfaces of an AT-cut crystal diaphragm. A pair of excitation electrodes E and E are formed on each of the front and back main surfaces of the crystal diaphragm so as to face each other with the crystal diaphragm interposed therebetween. An extraction electrode is extracted from each of the pair of excitation electrodes toward one end side of the long side of the quartz crystal diaphragm. Each terminal portion of the pair of lead electrodes is an electrode for bonding (adhesive electrode). In FIG. 1, only the excitation electrode (E) is shown, and the drawing electrode and the adhesive electrode are not shown.

  The 1st container 4 is a box-shaped container body which the upper part opened, and is substantially rectangular in planar view. The first container 4 includes a flat bottom plate portion 40 made of an insulating material and a metal frame portion 5 attached to the outer peripheral portion of the upper surface of the bottom plate portion 40. The bottom plate portion 40 is composed of two layers (a first layer 41 as a lower layer and a second layer 42 as an upper layer) made of ceramic green sheets. A tungsten (W) metallization layer (not shown) is formed in a circumferential shape on the outer peripheral part of the upper surface of the second layer 42, and a frame part 5 made of Kovar is placed on the metallization layer via a brazing material. It is attached. The frame portion 5 has an annular shape in plan view, and a lid 9 is joined to the upper surface thereof by seam welding.

  The lid 9 is a flat plate having a substantially rectangular shape in plan view. The lid 9 is made of Kovar, and the surface of the base is plated with nickel and gold. A sealing material is formed in a frame shape on the outer peripheral portion of the main surface on the side joined to the frame portion 5 of the lid. Next, an outline of the first container will be described.

  As shown in FIG. 1, a space surrounded by the frame portion 5 of the first container and the upper surface of the second layer 42 of the bottom plate portion is a concave portion C1, which is substantially rectangular in plan view. On one short side of the inner bottom surface 420 (upper surface of the second layer 42) of the recess C1, a pair of mounting electrodes 6 and 6 that are conductively bonded to the crystal vibrating piece 7 are formed in parallel (FIG. 1). Then only one is shown). On the pair of mounting electrodes 6 and 6, the pair of adhesive electrodes (not shown) of the quartz crystal vibrating piece described above are conductively bonded in a one-to-one manner via the conductive adhesives S and S. As a result, one end side of the long side of the quartz crystal vibrating piece 7 is cantilevered and bonded onto the mounting electrode 6. In the embodiment of the present invention, a portion where the crystal vibrating piece 7 is cantilevered and bonded to the mounting electrode 6 is referred to as a “joining portion”. In this embodiment, a silicone-based conductive resin adhesive is used for the conductive adhesive S, but a conductive resin adhesive other than a silicone-based adhesive may be used.

  The outer bottom surface 410 (the lower surface of the first layer 41) of the first container 4 shown in FIG. 2 is substantially rectangular in plan view, and the bottom electrode 8 (8a, 8b, 8c, 8d) is formed. As for the bottom electrode 8a, the corner portion on the peripheral side of one long side of the outer bottom surface 410 is chamfered. This is a mark for identifying the directionality of the four bottom electrodes.

  In the present embodiment, the mounting electrode 6 and the bottom electrode 8 have a laminated structure of three kinds of metals. Specifically, in these electrodes, a tungsten layer is formed by printing on the base material (ceramic) of the first container, and a nickel plating layer and a gold plating layer are formed on the tungsten layer in this order by electrolytic plating. The plating layer is laminated. In this way, the mounting electrode, the bottom electrode, and the like are collectively formed. In addition, the metal material which comprises each layer of the electrode mentioned above is an example, and you may use another metal material. For example, molybdenum may be used instead of tungsten.

  As shown in FIG. 2, the four corners of the outer bottom surface 410 of the first container that is substantially rectangular in plan view are cut out in a quarter circle in plan view. Specifically, each of the four ridges on the outer side surface of the bottom plate portion 40 of the first container is cut out so as to penetrate the bottom plate portion in the thickness direction, and the inside of each of these four cut-out portions. Of the wall surface, the conductor is attached only to the thickness of the first layer 41. In this way, a part of the inner wall surface of the part cut into a quarter columnar shape is referred to as a castellation, and is indicated by reference numerals 40a, 40b, 40c, and 40d in FIG. Yes. Each of the conductors in the castellations 40a to 40d is electrically connected to each of the bottom electrodes 8a to 8d on the outer bottom surface 410 via the lead portions L1, L2, L3, and L4 having a quarter arc shape in plan view. ing. In addition, the planar view shape of the drawer | drawing-out part is not limited to 1/4 arc shape, Other shapes may be sufficient. For example, it may have a plan view shape extending from one castellation in a band shape (straight line shape) toward the corner portion of the bottom electrode located closest to the castellation.

  Of the four bottom electrodes 8a, 8b, 8c, and 8d, 8b and 8d are routed via internal wiring (not shown) provided between the first layer 41 and the second layer 42 and castellations 40b and 40d. The pair of mounting electrodes 6 and 6 are electrically connected to each other. The remaining bottom electrodes 8a and 8c are electrically connected to the metal lid 9 via vias (not shown) and the frame part 5 (ground terminals).

In the present embodiment, a plurality of vias filled with a conductor are formed in a through hole that penetrates the inside of the second layer 42 in the thickness direction in the bottom plate portion 40 (not shown). One end of each of the plurality of vias is exposed on the upper surface of the second layer 42, and one end of a part of the vias is electrically connected to the metal frame portion 5. On the other hand, the other ends of the partial vias are finally electrically connected to the bottom electrodes 8a and 8c via the castellations 40a and 40c, respectively. By connecting the bottom electrodes 8a and 8c to the ground terminal of the external substrate via the second container at the ground potential, an electromagnetic shielding effect can be obtained. Only one of the bottom electrodes 8a and 8c may be connected at the ground potential.
The above is the outline of the crystal resonator. Next, the second container and the like will be described with reference to FIGS.

  As shown in FIG. 3, the 2nd container 3 is a box-shaped container body which the upper part opened, and is substantially rectangular in planar view. The second container 3 is integrally formed by firing in a state where two ceramic green sheets are laminated. Specifically, the second container 3 includes a flat plate-like first layer 30 and a frame-like second layer 31 laminated on the outer peripheral portion of the upper surface of the first layer 30 (see FIG. 1). A space surrounded by the upper surface of the first layer 30 and the second layer 31 is a recess C2. That is, the second layer 31 is a side wall that surrounds the recess C2. FIG. 3 shows a state where the oscillation circuit element 13 is mounted in the recess C2.

  The concave portion C2 is a space in which the oscillation circuit element 13 is mounted, and has a substantially rectangular shape in plan view except for a notch portion described later. Although not shown in FIG. 3, a plurality of oscillation circuit element mounting pads and electrode patterns (wirings) drawn from these pads are formed on the inner bottom surface 300 (the upper surface of the first layer 30) of the recess C2. Is formed. That is, the plurality of oscillation circuit element mounting pads are ends of electrode patterns (not shown).

  The 2nd layer 31 which is a side wall of the 2nd container consists of a set of opposed short sides and a set of opposed long sides. That is, it is composed of four side walls: short side portions 3a and 3b which are side walls on the short side and long side portions 3c and 3d which are side walls on the long side. Among these, as shown in FIG. 3, a notch 31 is formed in the short side 3a on one end side, and a notch 32 is formed in the short side 3b on the other end side.

  Using the notches 31 and 32, a needle or nozzle for dropping an underfill agent, or a shear strength measurement tool can be inserted. By spreading the underfill agent in the gap between the oscillation circuit element 13 and the inner bottom surface 300 of the recess, the reliability of joining the oscillation circuit element 13 to the second container 3 can be improved. In this embodiment, an epoxy resin is used as the underfill agent, and the symbol R in FIG. 1 represents a state after the underfill agent is cured.

  The four corners of the second container that is substantially rectangular in plan view are cut out in a quarter circle in plan view. Specifically, each of the four ridges on the outer surface of the first layer 30 and the second layer 31 of the second container is cut out so as to penetrate in the thickness direction of the container. Of the inner wall surface of each part, the conductor is deposited only on the thickness of the first layer 30. In FIG. 3, a castellation 33 (33 a, 33 b, 33 c, 33 d) is shown in which a conductor is attached to a part of the inner wall surface of a portion cut into a quarter columnar shape.

  The upper surface 310 (upper surface of the side wall) of the second layer 31 shown in FIG. 3 is a flat surface, and four bonding electrodes 10a, 10b, 10c, and 10d are formed at the four corners of the upper surface. These bonding electrodes have a one-to-one correspondence with the four bottom electrodes 8a, 8b, 8c, 8d provided on the outer bottom surface 410 of the crystal resonator 2. That is, the bonding electrode 10a corresponds to the bottom electrode 8a, the bonding electrode 10b corresponds to the bottom electrode 8b, the bonding electrode 10c corresponds to the bottom electrode 8c, and the bonding electrode 10d corresponds to the bottom electrode 8d.

  The joining electrode 10 (10a, 10b, 10c, 10d) has a shape in plan view that is bent into an alphabetic “L” shape. That is, the bonding electrode 10 is provided so as to be along a virtual corner portion of the substantially rectangular concave portion C2 in plan view (because the corner portion is curved in FIG. 3) and two adjacent sides across the corner portion. It is formed on the upper surface of the side wall (the upper surface 310 of the second layer 31). That is, the inner peripheral edge of the bonding electrode 10 is formed along the inner peripheral edge of the side wall. On the other hand, corners of the outer peripheral edge of the bonding electrode 10 that are close to the castellations 33a to 33d of the second container are cut out into a quarter circle in plan view.

  The area of the bonding electrode 10 (10a, 10b, 10c, 10d) in plan view is smaller than the area of the bottom electrode 8 of the crystal resonator 2 in plan view. In the state where the first container is positioned and mounted on the upper part of the second container, the outer edge excluding the inner peripheral edge facing the concave portion C2 of the bonding electrode 10 in a plan view “L” shape and the outer edge of the bottom electrode 8 are They are almost the same in plan view. That is, in the state after the first container and the second container are joined, a part of the bottom electrode 8 is located above the recess C <b> 2 beyond the inner peripheral edge of the joined electrode 10 in plan view transmission.

  A pair of long side portions 3c, 3d of the side wall of the second container has four vias (half vias) V1, V2, V2 cut into the inner wall surface of the side wall in a semi-cylindrical shape and filled with conductors therein. V3 and V4 are formed. That is, the vias V1, V2, V3, V4 are exposed on the inner wall surface of the side wall of the second container. One end sides of these four vias are electrically connected to the four junction electrodes, respectively (see FIG. 3). The other end sides of these four vias are electrically connected to a part of the plurality of oscillation circuit element mounting pads (see FIG. 1) on the inner bottom surface 300 of the recess C2.

  As shown in FIG. 4, the outer bottom surface 301 (the lower surface of the first layer 30) of the second container 3 has a substantially rectangular shape in plan view, and the external connection terminals 12 (12 a, 12 b) are connected to the four corners of the outer bottom surface 301. , 12c, 12d).

  The oscillation circuit element 13 is an integrated circuit element (bare chip IC) in which an oscillation circuit, a temperature sensor, a temperature compensation circuit, and the like are integrated on a single chip, and the appearance thereof is a rectangular parallelepiped. A plurality of various function terminals (not shown) on the circuit surface side of the oscillation circuit element 13 (IC) are conductively joined to the plurality of oscillation circuit element mounting pads (11) via metal bumps B (see FIG. 1). ).

Of the various functional terminals of the oscillation circuit element 13, two terminals (crystal terminals) are electrically connected to the bonding electrodes 10b and 10d via the electrode pattern and vias described later. Then, the bonding electrodes 10b, 10d of the second container and the bottom electrodes 8b, 8d of the first container are respectively conductively bonded, so that the two crystal terminals of the oscillation circuit element 13 finally become the crystal vibrating piece 7 Are electrically connected to the excitation electrodes E, E formed on the front and back main surfaces. The functional terminals other than the terminals connected to the crystal resonator element 7 of the oscillation circuit element 13 are connected to the bonding electrodes 10a and 10c and the four external connection terminals 12a via the electrode patterns, vias, and castellations 33a and 33c of the second container. ~ 12d are electrically connected.

FIG. 5 shows a transparent display of the position of the bottom electrode 8 in a state where the crystal resonator 2 is bonded onto the second container 3 with a dotted line. As shown in FIG. 5, in the state after the first container 4 and the second container 3 are joined, a part of the inner peripheral edge of the bottom electrodes 8 a to 8 d is transparent in a plan view and the joined electrodes 10 a to 10 a are used.
It is located above the recess C2 beyond the inner periphery of 10d. At this time, one end side of the vias V1 to V4 is located in the region of the bottom electrodes 10a to 10d.

  FIG. 6 is a schematic cross-sectional view taken along the line BB in FIG. 5 in a state where the crystal resonator is mounted on the upper portion of the second container. According to this, the bonding material of the bottom electrodes 8a and 8d (8b and 8c) extends from the inner peripheral edge located above the recess C2 to the other end side of the vias V1 and V4 (vias V2 and V3) (close to the inner bottom surface of the recess). Since the fillets F and F are formed, the bonding strength between the first container and the second container can be improved. Note that the lower end of the fillet F is in the vicinity of the upper surface of the underfill in order to heat and melt the bonding material after injecting and curing the underfill agent into the recess C2.

  Since the present invention has a configuration in which the via is exposed on the inner wall surface of the side wall of the second container, the space can be saved as compared with the case where the conductor is formed in a planar shape on the inner wall surface of the side wall. A short circuit with the electrode pattern on the inner bottom surface can be prevented. Further, the amount of metal used can be reduced as compared with the case where the bonding electrode is formed on two surfaces so as to extend from the upper surface of the side wall to the inner wall surface of the side wall.

  In the embodiment of the present invention, since the lead portions L1, L2, L3, and L4 continuous with the castellations 40a to 40d are formed, the fillet of the joining material is formed from the lead portions L1 to L4 to the joint electrodes 10a to 10d. Is done.

  In addition, by controlling the amount of the bonding material, the bonding material 14 may extend to the conductor portions of the castellations 40a to 40d of the first container in addition to the lead portions L1 to L4 as shown in FIG. That is, the bonding material reaches each of the lead portions L1 to L4 and the bottom electrodes 8a to 8d while forming the rising 14h of the bonding material to the conductor portions (part or all) of the castellations 40a to 40d. It may be.

  According to such a bonding form, in addition to the fillet of the bonding material formed by the vias V1 to V4, the fillet of the bonding material from the lead portions L1 to L4 to the bonding electrode is formed, and the castellations 40a to 40d 14h of the joining material is formed on the conductor portion. Thereby, the joint strength between the first container and the second container can be further improved. Such a bonding form is suitable for in-vehicle applications that require high bonding reliability and when the crystal oscillator is further downsized.

  FIG. 8 shows a transparent display of the positions of the pair of mounting electrodes 6 and 6 in a state in which the crystal unit 2 is bonded onto the second container 3. As shown in FIG. 8, the vias V <b> 1 to V <b> 4 are exposed on the inner wall surfaces of the pair of long side portions 3 c and 3 d that are side walls that do not overlap with the pair of mounting electrodes 6 and 6 in plan view. That is, four vias are formed only on the inner wall surface of one set of long side portions that are side walls that do not overlap with the “joining portion” in plan view.

  With the arrangement of such vias, the TTFF characteristic (Time To First Fix) can be improved. This is due to the following reason. One of the factors affecting the TTFF characteristics is the stress acting on the quartz crystal resonator element. According to the configuration of the crystal oscillator shown in FIG. 8, since no via is disposed below the “joining portion”, the joining material is provided on the short side portion 3 a of the second container that does not overlap the joining portion in plan view transmission. The fillet is not formed. This makes it difficult for contraction stress acting on the fillet of the bonding material to be transmitted to the quartz crystal resonator element. As described above, the stress transmitted to the quartz crystal resonator element is alleviated, so that the fluctuation of the oscillation frequency is suppressed and the TTFF characteristics can be improved.

-Modification of the embodiment of the present invention-
FIG. 9 shows a schematic top view of a second container according to a modification of the embodiment of the present invention. In addition, about the same structure as embodiment of this invention mentioned above, the same number is attached | subjected and the description is omitted.

  In the modification of the embodiment of the present invention, the bottom electrode of the crystal resonator is the same as the above-described embodiment of the present invention in both shape and area.

  FIG. 9 shows a transparent display of the position of the bottom electrode in a state where the crystal unit 2 is bonded onto the second container 15 with a dotted line. As shown in FIG. 9, in the state after the first container 4 and the second container 15 are joined, a part of the inner peripheral edge of the bottom electrodes 8a to 8d exceeds the inner peripheral edge of the joined electrodes 16a to 16d in plan view transmission. And located above the recess C3. In the modification of the embodiment of the present invention, the area of the four bonding electrodes 16a to 16d is larger than the area of the bonding electrodes (10a to 10d) in the above-described embodiment of the present invention. Regions where 16a to 16d protrude from the bottom electrodes 8a to 8d are indicated by thick diagonal lines.

  Specifically, the bonding electrode 16a protrudes from the bottom electrode 8a in the center direction of the short side of the second container. Furthermore, a part of the inner periphery of the bottom electrode 8a extends over the recess C3 beyond the inner periphery of the bonding electrode 16a. Similarly, the bonding electrodes 16b to 16d are also protruded toward the center of the short side of the second container with respect to each of the bottom electrodes 8b to 8d, and the inner peripheral edge of each of the bottom electrodes 8d to 8d. A part of the bonding electrodes 16d to 16d extends over the recess C3 beyond the inner peripheral edge.

  In this way, the four bonding electrodes 16a to 16d protrude from the edge of the bonding electrode to the center of the short side of the second container with respect to each of the four bottom electrodes 8a to 8d. Since it becomes easy to form the fillet of the bonding material over the edge, the bonding strength can be improved.

-Other Modifications of Embodiments of the Present Invention-
10 to 12 are schematic top views of a second container according to another modification of the embodiment of the present invention. In addition, about the same structure as embodiment of this invention mentioned above, the same number is attached | subjected and the description is omitted.

  In another modification of the embodiment of the present invention shown in FIG. 10, the vias V1 to V4 are formed in the junction electrodes (18a to 18d) located at the long side portions 17c and 17d, and the vias V5 to V8 are short. It is formed in the junction electrode of the side parts 17a and 17b. That is, one via is formed in each of the long side and the short side adjacent to one corner of the inner periphery of the recess C4 in the region of the bonding electrode. In the case of the via having such a configuration, since the solder fillet is formed not only in the long side portion but also in the short side portion, the bonding strength between the first container and the second container can be further improved.

  In another modification of the embodiment of the present invention shown in FIG. 11, the vias V <b> 9 to V <b> 12 are three-quarters around the virtual corner (not shown) of the inner periphery of the recess C <b> 5. It has become a shape. In the case of the via having such a configuration, a total of four vias are formed in the region of the bonding electrodes 20a to 20d. Since these four vias are formed at the imaginary corner portion of the inner periphery of the second layer 31 so as to extend over both the long side portion and the short side portion of the side wall, they extend to both the long side portion and the short side portion. A filler fillet is formed. With such a configuration, the bonding strength between the first container and the second container can be improved with a small number of vias.

Furthermore, in another modification of the embodiment of the present invention shown in FIG. 12, the number of vias V13 to V16 and the positions where they are formed are the same as V1 to V4 in the above-described embodiment of the present invention. The configuration of the two containers is different from the embodiment of the present invention described above. The bottom electrode of the crystal resonator is the same as the above-described embodiment of the present invention in terms of shape and area.

  The four corners 23a to 23d of the second container 21 are perpendicular to each other in plan view, and the above-described castellation (33) is not formed. Thus, since the castellation is not formed in the second container, the rigidity of the container body can be improved as compared with the container in which the castellation is formed. Furthermore, since the area of the upper surface of the side wall can be secured more widely, the region where the bonding electrode can be arranged can be enlarged.

  Moreover, the notch part is not formed in the short side part 21a of the one end side of the 2nd container 21, and the short side part 21b of the other end side. Since notches are not formed in all the side walls 21a to 21d of the second container as shown in FIG. 12, the rigidity of the container body can be improved as compared with a container in which the notches are formed in the side walls. . As described above, the second container 21 shown in FIG. 12 is suitable when the size of the piezoelectric oscillator is further reduced because the region where the bonding electrode can be arranged can be expanded while increasing the rigidity of the container. .

  Four junction electrodes 22a, 22b, 22c, and 22d are formed at the four corners of the upper surface 210 of the side wall of the second container 21, and these junction electrodes are the four bottom electrodes 8a, There is a one-to-one correspondence with 8b, 8c, 8d.

  The bonding electrode 22 (22a to 22d) has a shape bent in a substantially “L” shape in plan view, but a part of the configuration is different from the embodiment of the present invention. Specifically, the inner peripheral edge of the bonding electrode 22 is formed along the inner peripheral edge of the side wall, but the corner portion of the outer peripheral edge of the bonding electrode 21 that is closest to the corner portions 23a to 23d of the second container is a right angle. It has become. With such a configuration, the area of the bonding electrode in plan view is relatively larger than that of the bonding electrode 10 in the above-described embodiment of the present invention. Thereby, the amount of the bonding material interposed between the bonding electrode and the bottom electrode can be increased.

As shown in FIG. 12, in the state after the first container 4 and the second container 21 are joined, the joining electrodes 22a to 22d are protruded from the bottom electrodes 8a to 8d in plan view transmission.
Specifically, the bonding electrode 22 protrudes from the bottom electrode 8 on the upper surfaces of the two short side portions 21a and 21b and the two long side portions 21c and 21d, and the lead portions L1 to L4 of the crystal resonator 2 On the outside, a region including the corners of the bonding electrodes 22a to 22d protrudes.

  According to the above configuration, since the region including the corners of the bonding electrodes 22a to 22d protrudes outward from the lead portions L1 to L4, the lead portions L1 to L4 from the periphery including the corner portions of the bonding electrodes 22a to 22d. A fillet of a bonding material is formed around the periphery of the material. Further, since the bonding electrode 22 protrudes outward from the bottom electrode 8 on the upper surfaces of the two short side portions 21a and 21b and the two long side portions 21c and 21d, the bottom electrode 8a extends from the bonding electrodes 22a to 22d. A fillet of bonding material is formed over ˜8d.

  On the other hand, on the inner peripheral side of the bonding electrode, the fillet of the bonding material extends from the inner peripheral edge located above the concave portion C6 of the bottom electrodes 8a to 8d to the other end side of the vias V13 to V16 (near the inner bottom surface of the concave portion C6). Each is formed.

  By forming the fillet of the bonding material in the plurality of regions as described above, the bonding strength between the first container and the second container can be further improved without increasing the number of vias formed.

  The number of vias formed in the present invention is not limited to the number of formations in the above-described embodiment of the present invention and its modifications and other modifications, depending on the size of the bonding electrode, the second container, and the like. You may increase / decrease suitably. Further, the via formation position is not limited to the formation position in the embodiment of the present invention, its modifications, and other modifications as long as it is exposed to the inner wall surface of the side wall of the second container. Further, in the embodiment of the present invention and its modifications and other modifications, the crystal oscillator is rectangular in plan view, but may be square in plan view. Further, the side wall of the second container may be square in plan view.

  In the embodiment of the present invention and its modified examples and other modified examples, a temperature-compensated crystal oscillator (TCXO: Temperature Compensated Oscillator) has been described as an example of a piezoelectric device, but is not limited to a TCXO and has a temperature compensating function. The present invention can also be applied to a crystal oscillator (SPXO) that is not provided. Furthermore, the present invention can also be applied to a piezoelectric vibrator to which a temperature sensor such as a thermistor is applied as an electronic component element. In this case, as an electronic component element mounting pad, for example, a via that electrically connects a thermistor mounting pad on which a chip-type thermistor is mounted and a bonding electrode is exposed to the inner wall surface of the side wall of the second container. Good.

  The present invention can be implemented in various other forms without departing from the spirit or main features thereof. Therefore, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is indicated by the 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.

DESCRIPTION OF SYMBOLS 1 Crystal oscillator 3, 15, 17, 19, 21 2nd container 4 1st container 7 Crystal vibrating piece 8 Bottom part electrode 10, 16, 18, 20, 22 Junction electrode V1-V16 Via

Claims (3)

The first container includes a mounting electrode on which the piezoelectric vibrating piece is mounted, and a bottom electrode led from the mounting electrode to the outer bottom surface of the container,
The second container includes a recess in which the electronic component element is mounted, an electronic component element mounting pad provided on the inner bottom surface of the recess, a side wall surrounding the recess, and the bottom electrode provided on the upper surface of the side wall. A corresponding bonding electrode, and a via that is exposed on the inner wall surface of the side wall and electrically connects the bonding electrode and the electronic component element mounting pad,
The bottom electrode is bonded onto the bonding electrode via a bonding material so that the first container covers the recess of the second container,
In the state after the joining, a part of the bottom electrode is positioned above the concave portion beyond the inner peripheral edge of the joining electrode in plan view transmission,
A piezoelectric device in which a fillet of the bonding material is formed from a part of a bottom electrode located above the recess to the via. In Claim 1, the electronic component element is an oscillation circuit element,
The second container includes an oscillation circuit element mounting pad provided on the inner bottom surface of the recess, and a via that is exposed on the inner wall surface of the side wall and electrically connects the bonding electrode and the oscillation circuit element mounting pad. A piezoelectric oscillator comprising: The first container has a rectangular parallelepiped shape, and each of the four ridges on the outer side surface of the container is cut out in the thickness direction of the container up to the outer bottom surface of the first container, and a conductor is covered on the inner wall surface. A worn castellation is formed,
The bottom electrode is formed at the four corners of the outer bottom surface of the first container through a drawer continuous with the castellation.
In the state where the first container and the second container are joined, the lead-out portion protrudes outward with respect to the outer peripheral edge of the joining electrode, and the joining material extends to the bottom electrode and at least the lead-out portion. The piezoelectric device according to claim 1 or 2.

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