JP2017034404A - Piezoelectric oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric oscillator having excellent TTFF characteristics while adapted to the downsizing.SOLUTION: In a crystal oscillator 1, a bottom electrode 7 of an outer bottom surface 410 of a first container 4 and a joint electrode 11 provided on the upper surface of a side wall surrounding a recess C2 of a second container 3 are conductively joined through a joint member. A crystal oscillator 2 includes a joint part 16 in which a crystal vibration piece 9 is open-side bonded to a mounted electrode 6. A notch part nt formed by notching a part of the inner wall surface of the side wall of a second container is formed on a side not corresponding to the joint part 16 out of sides constituting the side walls in a plan view.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a piezoelectric oscillator in which a piezoelectric vibrator is joined and integrated on an upper part of a container containing an oscillation circuit element.

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

  Depending on the application of the piezoelectric oscillator, a so-called TTFF (Time To First Fix) characteristic, which is a time until the first position information is calculated after the GPS receiver is turned on, may be required. As one of the factors affecting the TTFF characteristic, a stress acting on the piezoelectric vibrating piece can be considered. This will be described next.

  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. At this time, the upper container is bent due to the propagation of the stress, and the stress is transmitted to the piezoelectric vibrating piece through the joint between the upper container and the piezoelectric vibrating piece. Thus, the inventor considered that the transmission of the stress to the piezoelectric vibrating piece may cause a variation in the oscillation frequency and deteriorate the TTFF characteristics.

  By the way, in the piezoelectric oscillator having the two-story structure described above, an underfill agent is usually applied to the gap between the bottom surface of the oscillation circuit element (bare chip IC) and the inner bottom surface of the recess in which the oscillation circuit element is mounted using a dispenser device. Injected. Specifically, the tip of the nozzle is inserted into the gap between the inner wall surface of the recess and the outer peripheral side surface of the IC, and an underfill agent is dropped, and the underfill agent is inserted into the gap between the bottom surface of the oscillation circuit element and the inner bottom surface of the recess. Is trying to spread.

  Also, in order to save space, flip chip via metal bumps for electrical connection between a plurality of terminals on the active surface of the IC chip and a plurality of terminals for IC mounting provided on the inner bottom surface of the recess. Sometimes done by bonding. In this case, the shear strength may be measured to confirm the connection reliability of the IC after flip chip bonding. In this shear strength measurement, it is necessary to insert the tip of a shear strength measurement tool into the gap between the inner wall surface of the recess and the outer peripheral side surface of the mounted IC.

  However, as the size of the piezoelectric oscillator is reduced, the gap between the inner wall surface of the recess and the outer peripheral side surface of the IC becomes smaller, so that it becomes difficult to insert a nozzle or a tool into the gap. For this reason, Patent Documents 2 to 3 disclose a piezoelectric oscillator in which a part of the side wall around the recess is thinned or removed in order to secure an insertion space.

  In the case of the piezoelectric oscillator as disclosed in Patent Documents 2 to 3, the underfill can be easily injected while corresponding to downsizing, but the rigidity of the side wall portion of the lower container is reduced by the thinning or the notch. Will fall. In particular, since the rigidity of the side wall at the position of the lower container corresponding to the joint between the upper container and the piezoelectric vibrating piece is reduced, the stress transmitted from the external substrate or the like is also applied to the joint between the upper container and the piezoelectric vibrating piece. It becomes easy to be transmitted. As a result, the oscillation frequency fluctuates and the TTFF characteristics may be deteriorated.

Japanese Patent No. 2974622 JP 2007-28454 A Japanese Patent No. 3997078

  The present invention has been made in view of this point, and an object of the present invention is to provide a piezoelectric oscillator having excellent TTFF characteristics while corresponding to downsizing.

  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, a bottom electrode led out from the mounting electrode to the outer bottom surface of the container, and the piezoelectric vibrating piece includes the A second container having a concave portion in which the oscillation circuit element is mounted, a side wall surrounding the concave portion, and an upper surface of the side wall corresponding to the bottom electrode. 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, and a part of the inner wall surface of the side wall is cut away. The cut-out portion thus formed is a piezoelectric oscillator formed on a side that does not correspond to the joint portion in a plan view among the sides constituting the side wall.

  According to the above-described invention, the stress transmitted to the piezoelectric vibrating piece is relaxed, thereby suppressing the fluctuation of the oscillation frequency and improving the TTFF characteristics. This is because in the present invention, in the second container, the cutout portion is formed on a side that does not correspond to the joint portion in a plan view among the sides constituting the side wall. That is, since the notch is not formed in the side corresponding to the joint, the rigidity of the side wall portion of the side is not reduced. This makes it difficult for the stress transmitted from the external substrate or the like to be transmitted to the joint between the first container and the piezoelectric vibrating piece. As a result, the stress transmitted to the piezoelectric vibrating piece is alleviated and fluctuations in the oscillation frequency are suppressed, so that the TTFF characteristics can be improved.

  Moreover, according to the said structure, since the notch part is formed in the side wall of a 2nd container, a part of clearance gap between the inner wall face of a recessed part and the outer peripheral side surface of an oscillation circuit element can be ensured widely. That is, it becomes easy to insert a needle and nozzle for dropping the underfill agent through the notch and a tool for measuring shear strength. In addition, since the cutout portion is formed on a side that does not correspond to the joint portion in a plan view among the sides constituting the side wall of the second container, the second container of the oscillation circuit element is improved while improving the TTFF characteristics. A small piezoelectric oscillator with improved bonding reliability can be obtained.

  In order to achieve the above object, the upper surface of the side wall of the second container has a substantially rectangular frame shape in plan view, and the side wall includes a pair of opposing short sides and a pair of opposing long sides. Thus, the cutout portion may not be formed in the short side portion corresponding to the joint portion of the pair of short side portions, and may be formed in the short side portion not corresponding to the joint portion.

  According to the above invention, since the notch is formed only on the short side and is not formed on the long side, the amount of bending that occurs in the long side when stress is applied to the second container is suppressed. can do. In the case of the second container having a rectangular shape (rectangular shape) in plan view, the amount of bending is relatively larger on the long side than on the short side. Is not formed, it is possible to prevent the rigidity of the side wall on the long side from being lowered. Thereby, the bending amount of the long side of a 2nd container can be suppressed. Furthermore, the notch is formed only in a short side portion that does not correspond to the joint portion of the pair of short side portions. This makes it difficult for the stress transmitted from the external substrate or the like to be transmitted to the joint between the first container and the piezoelectric vibrating piece. As a result, the stress transmitted to the piezoelectric vibrating piece is alleviated and fluctuations in the oscillation frequency are suppressed, so that the TTFF characteristics can be improved.

  In order to achieve the above object, when the oscillation circuit element has a rectangular parallelepiped shape and the oscillation circuit element is mounted in the recess of the second container, the notch is one of the outer peripheral side surfaces of the oscillation circuit element. You may form in the side wall of the 2nd container facing one short side surface.

  According to the above invention, the shear strength can be measured more accurately. This is because, when shear strength is measured when a rectangular parallelepiped oscillator circuit element is ultrasonically bonded to an oscillator circuit element mounting pad via a metal bump, for example, the shear strength measurement is performed in a direction parallel to the longitudinal direction of the oscillator circuit element. Inserting the tip of the tool and applying tensile stress in the longitudinal direction of the oscillation circuit element can perform more accurate measurements than applying tensile stress in the transverse direction perpendicular to the longitudinal direction of the oscillation circuit element. Because it can.

  In order to achieve the above object, when the first container and the second container are joined, a part of the inner peripheral edge of the bottom electrode is a part of the joined electrode when viewed in a plan view. A part of the outer peripheral edge of the bonding electrode may protrude outward from the outer peripheral edge of the bottom electrode, over the peripheral edge and above the recess.

  According to the said invention, the joining reliability of a 1st container and a 2nd container can be improved, and a TTFF characteristic can be improved further. This will be described next. In a state where the first container and the second container are joined, a part of the inner peripheral edge of the bottom electrode is positioned above the concave portion beyond the inner peripheral edge of the joined electrode when viewed in plan view. In addition, since a part of the outer peripheral edge of the bonding electrode protrudes outward with respect to the outer peripheral edge of the bottom electrode, a fillet (meniscus) of the bonding material is easily formed in a plurality of regions. By forming these fillets, the bonding strength between the first container and the second container is improved, and the bonding reliability can be increased.

  Specifically, a part of the inner peripheral edge of the bottom electrode is positioned above the concave portion beyond the inner peripheral edge of the bonding electrode, so that the inner peripheral edge of the bottom electrode is changed from the inner peripheral edge of the bonding electrode. It is possible to easily form a fillet of the bonding material over a part.

  Further, in the present invention, since the notch is not formed in the side wall of the side corresponding to the above-described bonding portion of the second container, the area of the bonding electrode on the upper surface of the side wall can be increased. Due to the enlargement, a part of the outer peripheral edge of the bonding electrode protrudes outward with respect to the outer peripheral edge of the bottom electrode, and a fillet of the bonding material can be formed. That is, the fillet of the bonding material can be easily formed from the outer peripheral edge of the bottom electrode to the outer peripheral edge of the bonding electrode.

  From the above, the form of the cross-linked fillet is different between the inner peripheral edge side and the outer peripheral edge side of the bottom electrode. In the case of such a cross-linked form of the fillet, the fillet of the bonding material is balanced in both the first container and the second container as compared with the case where the fillet cross-linked on the inner peripheral edge side and the outer peripheral edge side of the bottom electrode is the same. Since this is cross-linked, the bonding balance in the entire piezoelectric oscillator can be improved. In addition, since the first container and the second container are more firmly joined by the fillet of the joining material extending over a plurality of regions, it is possible to make it difficult for stress to be transmitted to the joint. Thereby, since the fluctuation | variation of an oscillation frequency is suppressed, a TTFF characteristic can be improved further.

  As described above, it is possible to provide a piezoelectric oscillator having excellent TTFF characteristics while corresponding to downsizing.

1 is a schematic cross-sectional view of a crystal oscillator according to an embodiment of the present invention. Schematic bottom view of a crystal resonator constituting the crystal oscillator of the present invention The upper surface schematic diagram of the 2nd container of the crystal oscillator of this invention Schematic top view showing a state where the oscillation circuit element is mounted on the second container Bottom view of the second container 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.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 5 by taking a crystal oscillator (TCXO) having a temperature compensation function as an example. FIG. 1 is a schematic cross-sectional view taken along the line AA in FIG. 4 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 have a long side of 1.65 mm and a short side of 1.25 mm. 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 a crystal resonator 2 is conductively bonded to the upper portion of the second container 3. In the crystal oscillator 1, four external connection terminals 13a, 13b, 13c, and 13d provided in the vicinity of the outer peripheral edge of the outer bottom surface 301 of the second container are joined to an external substrate via solder or the like. .

  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 9, a first container 4, and a lid 10 as main components. Hereinafter, an outline of each member constituting the crystal unit 2 will be described.

  In FIG. 1, a quartz crystal vibrating piece 9 is a rectangular piezoelectric element in plan view in which various electrodes are formed on the front and back main surfaces of an AT cut quartz crystal vibrating plate. 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 10 described later is joined to the upper surface thereof by seam welding.

  A space surrounded by the frame 5 and the upper surface of the second layer 42 is a recess 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 9 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 crystal vibrating piece described above are conductively bonded one-to-one via the conductive adhesive S. As a result, one end side of the long side of the crystal vibrating piece 9 is cantilevered and joined to the mounting electrode 6. In FIG. 1, a portion where the crystal vibrating piece 9 is cantilevered and bonded to the mounting electrode 6 is represented as a bonding portion 16. 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.

  A pillow 8 is formed on the other short side of the inner bottom surface 420 of the concave portion C1 and at a position corresponding to the lower end of the free end of the cantilevered crystal vibrating piece. This pillow 8 is formed by a metallization process of tungsten or molybdenum (Mo), and in a steady state, there is a gap between the free end of the quartz crystal vibrating piece. The presence of the pillow 8 can prevent contact between the free end and the inner bottom surface 420 of the recess C1 when the free end side of the crystal vibrating piece is bent due to external impact or the like. As a result, it is possible to prevent the crystal resonator element from being damaged and the oscillation frequency from being changed by the contact.

  As shown in FIG. 2, the outer bottom surface 410 (the lower surface of the first layer 41) of the first container 4 has a substantially rectangular shape in plan view, and the bottom electrode 7 (7a, 7b, 7c, 7d) are formed. In addition, about 7a among four bottom electrodes, the corner | angular part of the peripheral side of one long side of the outer bottom face 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 7 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 formed at the same time. 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.

  Of the four bottom electrodes 7a, 7b, 7c, 7d, 7b and 7d are connected via an internal wiring (not shown) provided between the first layer 41 and the second layer 42 and a castellation described later. The pair of mounting electrodes 6 and 6 are electrically connected to each other. The remaining bottom electrodes 7a and 7c are electrically connected to a metal lid 10 via vias (not shown) and a frame portion 5 described later (ground terminals).

  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 arc shape 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 portion of the first layer 41. A structure in which a conductor is attached to a part of the inner wall surface of a portion cut into a quarter columnar shape is referred to as castellation. In FIG. 2, the reference numerals 40a, 40b, 40c, and 40d are illustrated. Yes. The conductors in the castellations 40a to 40d are electrically connected to the bottom electrodes 7a to 7d of the outer bottom surface 410, respectively.

  In FIG. 1, a lid 10 is a flat plate having a substantially rectangular shape in plan view. The cover 10 is made of Kovar as a base material, and the surface of the base material 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.

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 end of the part of the vias is electrically connected to the bottom electrodes 7a and 7c through the four castellations 40a and 40c. An electromagnetic shielding effect can be obtained by connecting the bottom electrodes 7a and 7c (7a or 7c) to the ground terminal of the external substrate through the second container at the ground potential.
The above is the outline of the main constituent members of the crystal resonator. Next, the second container and the like will be described.

  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 second layer 31 and the upper surface of the first layer 30 is a concave portion C2, and is substantially rectangular in plan view except for a notch to be described later. The second layer 31 is a side wall that surrounds the recess C2.

  The four corners of the second container that is substantially rectangular in plan view are cut out in a quarter arc shape 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 attached only to the portion 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.

  A plurality of oscillation circuit elements bonded to a plurality of various functional terminals (not shown) of the oscillation circuit element 14 (IC) via metal bumps B on the inner bottom surface 300 (the upper surface of the first layer 30) of the recess C2. A mounting pad 12 (see FIG. 1) is formed. The plurality of oscillation circuit element mounting pads 12 are ends of electrode patterns (not shown).

  Of the various functional terminals of the oscillation circuit element 14, two terminals (crystal terminals) are electrically connected to the junction electrodes 11b and 11d via the electrode pattern and vias described later. Then, the bonding electrodes 11b and 11d of the second container and the bottom electrodes 7b and 7d of the first container are respectively conductively bonded, so that the two crystal terminals of the oscillation circuit element 14 finally become the crystal vibrating piece 9 Are electrically connected to the excitation electrodes E, E formed on the front and back main surfaces. The function terminals other than the terminals connected to the crystal resonator element 9 of the oscillation circuit element 14 are connected to the bonding electrodes 11a and 11c and the four external connection terminals 13a via the electrode patterns, vias, and castellations 33a and 33c of the second container. ˜13d are electrically connected.

  The upper surface 310 (upper surface of the side wall) of the second layer 31 is a flat surface, and four junction electrodes 11a, 11b, 11c, and 11d are formed at the four corners of the upper surface as shown in FIG. These bonding electrodes have a one-to-one correspondence with the four bottom electrodes 7a, 7b, 7c, 7d provided on the outer bottom surface 410 of the crystal unit 2. That is, the bonding electrode 11a corresponds to the bottom electrode 7a, the bonding electrode 11b corresponds to the bottom electrode 7b, the bonding electrode 11c corresponds to the bottom electrode 7c, and the bonding electrode 11d corresponds to the bottom electrode 7d.

  The bonding electrode 11 (11a, 11b, 11c, 11d) has a shape in plan view that is bent into an alphabetic “L” shape. Then, the bonding electrode 11 includes a corner portion (a curved corner portion in FIG. 3) of the substantially rectangular concave portion C2 in plan view and an upper surface of the side wall along the two adjacent sides across the corner portion ( An upper surface 310) of the second layer 31 is formed. That is, the inner peripheral edge of the bonding electrode 11 is formed along the inner peripheral edge of the side wall. On the other hand, of the outer peripheral edge of the bonding electrode 11, the corner close to the corner (castellations 33 a to 33 d) of the second container 3 is cut out in a quarter arc shape in plan view.

  The bonding electrode 11 (11a, 11b, 11c, 11d) corresponds to the bottom electrode 7 (7a, 7b, 7c, 7d) of the crystal resonator 2, but the area of the bonding electrode 11 is larger in plan view. It is smaller than the bottom electrode 7. In the state in which the first container is positioned and placed 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 11 in a plan view “L” shape, and the outer bottom face 410 of the bottom electrode 7. And the outer edge on the side facing the outer peripheral edge substantially coincide with each other in plan view.

  The joining electrode 11 (11a, 11b, 11c, 11d) is one end of four vias (half vias) (not shown) in which the inner wall surface of the second layer 31 as a side wall is cut out in a semi-cylindrical shape and a conductor is filled therein. Each side is electrically connected. The other ends of these four vias are electrically connected to a part of a plurality of oscillator circuit element mounting pads (not shown) on the inner bottom surface 300 of the recess C2.

  The second layer 31 is a rectangular frame body in plan view that surrounds the recess C2 and serves as a side wall of the second container. The side wall is composed of a pair of opposing short sides and a pair of opposing 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.

  As shown in FIG. 3, a notch nt is formed on the inner wall surface of the short side 3b on the other end facing the short side 3a on the one end. Here, the short side portion 3a on one end side is a side (W1) corresponding to the joint portion 16 in plan view in a state where the first container is positioned and joined to the upper portion of the second container. On the other hand, the short side 3b on the other end side is a side (W2) that does not correspond to the joint 16 in plan view in a state where the first container is positioned and joined to the upper part of the second container.

  The notch is preferably formed as far as possible from the side (W1) corresponding to the joint 16 in plan view from the viewpoint of propagation of stress to the joint 16. In this embodiment, the formation depth of the notch nt is a depth obtained by notching the entire thickness of the second layer 31, but in a state where only the thickness of a part of the side wall of the second container is notched. There may be. For example, the side wall portion of the second container may be composed of two layers of ceramic green sheets, and only the thickness of the uppermost sheet may be cut out to form a stepped cutout in a cross-sectional view. In addition, the opening width of the notch and the length of penetration in the width direction of the side wall take into consideration the diameter of the needle and nozzle for supplying the underfill agent, the size of the tool for measuring the shear strength, etc. Set as appropriate. In addition, the shape of the cutout in plan view is not limited to the shape in the embodiment of the present invention, and may be another shape.

  According to the said structure, the fluctuation | variation of an oscillation frequency can be suppressed by relieving the stress transmitted to the crystal vibrating piece 9, and a TTFF characteristic can be improved. This is because, in the second container 3, the notch nt is formed only on the side (W 1) that does not correspond to the joint portion 16 in plan view among the sides constituting the side wall. That is, since the notch is not formed in the side (W1) corresponding to the joint portion 16, the rigidity of the side wall portion of the side (W1) is not reduced. This makes it difficult for the stress transmitted from the external substrate or the like to be transmitted to the joint 16 between the first container and the quartz crystal vibrating piece. As a result, the stress transmitted to the crystal vibrating piece 9 is relaxed and fluctuations in the oscillation frequency are suppressed, so that the TTFF characteristics can be improved.

  The oscillation circuit element 14 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 one chip, and has an external appearance that is a rectangular parallelepiped. FIG. 4 shows a state in which the oscillation circuit element 14 is mounted in the recess C2 of the second container. In this state, the notch portion nt is the side wall (the short side portion 3b on the other end side) of the second container facing the short side surface 14W2 of the outer peripheral side surfaces (14L1, 14L2, 14W1, 14W2) of the oscillation circuit element 14. ).

  As shown in FIG. 4, in this embodiment, the notch nt is formed, so that the gap GP2 between the short side 3b on the other end side and the outer peripheral side surface 14W2 of the oscillation circuit element is shorter on the one end side. It is wider than the gap GP1 between the side 3a and the outer peripheral side surface 14W1 of the oscillation circuit element (GP1 <GP2). That is, it is possible to easily insert a needle, a nozzle, and a shear strength measurement tool for dropping an underfill into the notch nt using the GP2. In this embodiment, the underfill agent is dropped from the notch nt, and the symbol R in FIG. 1 represents the state after the underfill agent is cured. In this embodiment, an epoxy resin is used as the underfill agent. With the above-described configuration, the underfill agent can be more reliably distributed to the gap between the oscillation circuit element and the inner bottom surface of the recess, so that the reliability of joining the oscillation circuit element 14 to the second container 3 is improved. be able to.

  Moreover, according to the said structure, since the notch part nt is formed only in the short side part 3b, and is not formed in the long side parts 3c and 3d, when stress acts on the 2nd container 3, it is long side part. The amount of bending that occurs can be suppressed. In the case of the second container having a rectangular shape (rectangular shape) in plan view, the amount of bending is relatively larger on the long side than on the short side. Since the notch is not formed, it is possible to prevent the rigidity of the side wall on the long side from being lowered. Thereby, the bending amount of the long side of a 2nd container can be suppressed.

  Further, according to the above configuration, in the state where the rectangular parallelepiped oscillation circuit element 14 is mounted in the recess C2 of the second container, the notch nt of the second container facing the one short side surface 14W2 of the oscillation circuit element is provided. Since it is formed on the side wall (the short side 3b on the other end side), the shear strength can be measured more accurately. This is because, when shear strength is measured when a rectangular parallelepiped oscillator circuit element is ultrasonically bonded to an oscillator circuit element mounting pad via a metal bump, for example, the shear strength measurement is performed in a direction parallel to the longitudinal direction of the oscillator circuit element. Inserting the tip of the tool and applying tensile stress in the longitudinal direction of the oscillation circuit element can perform more accurate measurements than applying tensile stress in the transverse direction perpendicular to the longitudinal direction of the oscillation circuit element. Because it can.

  The outer bottom surface 301 (the lower surface of the first layer 30) of the second container 3 is substantially rectangular in a plan view as shown in FIG. 5, and the external connection terminals 13 (13a, 13b) are provided at the four corners of the outer bottom surface 301, respectively. , 13c, 13d). Of the four bottom electrodes, 13d is formed with a protruding portion 13t protruding in the long side direction of the outer bottom surface 301 from the side facing 13c. This protrusion 13t serves as a mark for identifying the directionality of the four external connection terminals.

  Note that in the embodiment of the present invention, a quarter-shaped lead-out portion (see FIG. 3) that is drawn from the castellations 40a to 40d of the crystal resonator 2 to the bottom electrodes 7a to 7d of the outer bottom surface 410 of the first container. Therefore, the fillet of the bonding material is also formed from these lead portions to the outer peripheral edge of the bonding electrode. Thereby, the joint strength between the first container and the second container can be improved.

-Modification of the embodiment of the present invention-
FIG. 6 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 position of the side wall where the notch is formed is the same as that of the above-described embodiment of the present invention. On the other hand, the area of the joining electrode of the second container is larger than the area of the joining electrode in the embodiment of the present invention. Specifically, all of the four bonding electrodes 18a, 18b, 18c, and 18d of the second container 17 are larger than the area of the bonding electrodes (11a to 11d) in the embodiment of the present invention. The joining electrodes 18a and 18d and the joining electrodes 18b and 18c have different shapes in plan view. The bottom electrode of the crystal resonator is the same as the above-described embodiment of the present invention in both shape and area.

  In FIG. 6, the position of the bottom electrode in a state where the crystal resonator is bonded onto the second container is displayed in a transparent manner with a dotted line. As shown in FIG. 6, when the state in which the first container (4) and the second container 17 are joined is viewed in plan view, a part of the inner peripheral edge of the bottom electrode 7 (7a to 7d) is joined. The electrodes 18a to 18d are positioned above the recess C2 beyond the inner peripheral edge of the electrodes 18a to 18d, and a part of the outer peripheral edge of the bonding electrodes 18a to 18d protrudes outward from the outer peripheral edge of the bottom electrode. In FIG. 6, regions where the bonding electrodes 18 a to 18 d protrude from the bottom electrodes 7 a to 7 d are indicated by thick diagonal lines.

  Specifically, the bonding electrode 18a protrudes from the bottom electrode 7a in both the central direction of the short side of the second container and the central direction of the long side of the second container. Furthermore, a part of the inner peripheral edge of the bottom electrode 7a extends above the recess C2 beyond the inner peripheral edge of the bonding electrode 18a.

  The bonding electrode 18d protrudes from the bottom electrode 7d in the central direction of the short side of the second container. Furthermore, a part of the inner peripheral edge of the bottom electrode 7d extends above the recess C2 beyond the inner peripheral edge of the bonding electrode 18d.

  That is, in the plan view transmission, a part of the bottom electrodes 7a and 7d protrudes from the bonding electrodes 18a and 18d and reaches the recess C2. In addition, since the notch part is not formed in the short side part 3a which is the edge | side corresponding to the junction part (16), the junction electrodes 18a and 18d are the junction electrodes 11a and 11d in embodiment of this invention mentioned above. Is bigger than.

  On the other hand, the bonding electrode 18b protrudes from the bottom electrode 7b in both the central direction of the short side of the second container and the central direction of the long side of the second container. Furthermore, a part of the inner peripheral edge of the bottom electrode 7b extends above the recess C2 beyond the inner peripheral edge of the bonding electrode 18b. Similarly, the bonding electrode 18c protrudes from the bottom electrode 7c in both the central direction of the short side of the second container and the central direction of the long side of the second container. Furthermore, a part of the inner periphery of the bottom electrode 7c extends over the recess C2 beyond the inner periphery of the bonding electrode 18c.

  That is, in the plan view transmission, a part of the bottom electrodes 7b and 7c protrudes from the bonding electrodes 18b and 18c and reaches the recess C2. Since the joining electrodes 18b and 18c have a notch nt formed in the short side 3b, it is difficult to extend the end in the short side direction of the second container 17, so the second container 17 The end is extended in the long side direction.

  Thus, not only the bonding electrodes 18a and 18d formed on the short side portion 3a among the four bonding electrodes, but also the bonding electrodes 18b and 18c formed on the short side portion 3b have the area thereof in the embodiment of the present invention. By enlarging the area of the bonding electrode, the bonding balance in the entire piezoelectric oscillator can be improved. In the modification of the embodiment of the present invention, the total area of the four junction electrodes is larger than the area of the four junction electrodes in the embodiment of the present invention, but the short side portion that is the side corresponding to the junction portion. The area may be enlarged only for the two junction electrodes in 3a. Alternatively, the area may be enlarged only for the two junction electrodes in the short side portion 3b that is a side that does not correspond to the junction portion.

  According to the said structure, the joining reliability of a 1st container (4) and the 2nd container 17 can be improved, and a TTFF characteristic can be improved further. This is because part of the inner peripheral edge of the bottom electrodes 7a to 7d is located above the recess C2 beyond the inner peripheral edge of the bonding electrodes 18a to 18d when viewed in a plan view, and outside the bonding electrodes 18a to 18d. This is because part of the periphery protrudes outward from the outer periphery of the bottom electrodes 7a to 7d, so that fillets of the bonding material are easily formed in a plurality of regions. By forming these fillets, the bonding strength between the first container (4) and the second container 17 is improved, and the bonding reliability can be increased.

  According to the said structure, the form of the fillet bridge | crosslinked by the inner peripheral edge side and outer peripheral edge side of bottom part electrode 7a-7d differs. In the case of such a cross-linked form of the fillet, the fillet of the bonding material is balanced in both the first container and the second container as compared with the case where the fillet cross-linked on the inner peripheral edge side and the outer peripheral edge side of the bottom electrode is the same. Since this is cross-linked, the bonding balance of the entire crystal oscillator can be improved. In addition, since the first container and the second container are more firmly bonded by the fillet of the bonding material extending over a plurality of regions, it is possible to make it difficult for stress to be transmitted to the bonding portion (16). Thereby, since the fluctuation | variation of an oscillation frequency is suppressed, a TTFF characteristic can be improved further.

  In the modification of the embodiment of the present invention, the notch portion is formed only in the short side portion 3b. However, as another modification of the present invention shown in FIG. Cutout portions nt2 and nt3 may be formed only in the long side portions 19c and 19d. The notches nt2 and nt3 are semicircular in plan view, and are formed at the center of the pair of long sides 19c and 19d, respectively.

  The notches nt2 and nt3 in FIG. 7 are for dripping the underfill agent, and the shear strength is not measured, so the diameter is reduced to such an extent that a needle or nozzle having a smaller diameter can be inserted than the shear strength measurement tool. . Even if it is such a structure, the effect of this invention mentioned above can be acquired.

  Moreover, in the other modification of this invention shown in FIG. 8, three notch parts nt4, nt5, nt6 are formed. That is, a notch nt4 is formed in the short side 20b, a notch nt5 is formed in the long side 20c, and a notch nt6 is formed in the long side 20d. The notch part nt4 opens in the short side direction of the second container across the center of the short side part (20b), and opens larger in the short side direction of the second container than the notch part nt in FIG. Yes. Therefore, the joining electrodes 21b and 21c are in a state of reaching a part of the notch nt4. This notch nt4 is mainly used for inserting a shear strength measurement tool.

  On the other hand, the cutout part nt5 of the long side part 20c and the cutout part nt6 of the long side part 20d are used for dropping the underfill agent, and thus are formed smaller than the cutout part nt4. Yes. In this way, the reduction in the rigidity of the second container is suppressed by minimizing the region cut out in the long side portion that is relatively narrow compared to the short side portion.

  The notches nt5 and nt6 are located as far as possible from the side 20a corresponding to the joint (16), and the short side 20b from the center of the long sides 20c and 20d of the second container 20 is as far as possible. It is formed at a position spaced apart to the side. As shown in FIG. 8, the length of the second container 20 is such that the end portions of the joining electrodes 21b and 21c in the long side direction of the second container cover a part of the notches nt5 and nt6 in a side view of the second container. It is extended in the direction toward the center of the side. Thus, by extending the bonding electrode so as to reach the notch, the region where the fillet of the bonding material is formed at the time of bonding with the first container is expanded. Thereby, even if it is a case where a notch part is formed in the long side part of a side wall, the joint strength of a 1st container and a 2nd container can be improved and the rigidity of a 2nd container can be supplemented. In addition, by increasing the area of the bottom electrode on the outer bottom surface of the crystal resonator in plan view, the area where the bottom electrode and the bonding electrode overlap in plan view can be increased to improve the bonding strength. Even if it is such a structure, the effect of this invention mentioned above can be acquired.

  In the embodiment of the present invention and its modification, 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 modification, a temperature compensated crystal oscillator (TCXO: Temperature Compensated Oscillator) is exemplified as a piezoelectric oscillator. However, the crystal oscillator is not limited to TCXO and does not have a temperature compensation function. The present invention is also applicable.

  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.

  It can be applied to mass production of piezoelectric oscillators.

DESCRIPTION OF SYMBOLS 1 Crystal oscillator 2 Crystal oscillator 3, 17, 19, 20 2nd container 4 1st container
nt, nt2, nt3, nt4, nt5, nt6 Notch

Claims (4)

The first container includes a mounting electrode on which the piezoelectric vibrating piece is mounted, a bottom electrode led out from the mounting electrode to the outer bottom surface of the container, and a joint portion in which the piezoelectric vibrating piece is cantilevered to the mounting electrode; With
The second container includes a recess in which the oscillation circuit element is mounted, a side wall surrounding the recess, and a bonding electrode provided on the upper surface of the side wall and corresponding to the bottom electrode,
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,
A piezoelectric oscillator in which a cutout portion in which a part of an inner wall surface of the side wall is cut out is formed on a side that does not correspond to the joint portion in a plan view among sides forming the side wall. The upper surface of the side wall of the second container is a frame shape having a substantially rectangular shape in plan view,
The side wall is composed of a pair of opposing short sides and a pair of opposing long sides,
The notch portion is not formed in a short side portion corresponding to the joint portion among the pair of short side portions, and is formed in a short side portion not corresponding to the joint portion. The piezoelectric oscillator according to 1. In the state where the oscillation circuit element is a rectangular parallelepiped and the oscillation circuit element is mounted in the recess of the second container,
2. The piezoelectric oscillator according to claim 1, wherein the notch is formed on a side wall of the second container facing one short side surface of the outer peripheral side surfaces of the oscillation circuit element. In the state where the first container and the second container are joined,
When viewed through in plan view, a part of the inner peripheral edge of the bottom electrode is located above the recess beyond the inner peripheral edge of the bonding electrode, and a part of the outer peripheral edge of the bonding electrode is outside the bottom electrode. The piezoelectric oscillator according to any one of claims 1 to 3, wherein the piezoelectric oscillator protrudes outward with respect to the peripheral edge.

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