JP2019154026A - Piezoelectric vibration device - Google Patents

Abstract

To provide a piezoelectric vibration device having a high connection reliability between a container and a piezoelectric diaphragm and having good characteristics even if the device is ultra-compact.SOLUTION: A pair of excitation electrodes 22a and 22b is formed on each center side of the front and back main surfaces of a quartz diaphragm 2, and connection electrodes 241 and 242 drawn from the pair of excitation electrodes 22a and 22b are formed on one end side 2A of the quartz diaphragm 2. On the side surface of the one end side 2A of the quartz diaphragm 2, an exposed portion 28 where the substrate of the quartz diaphragm is exposed, and first side electrodes 241c and 242c adjacent to the exposed portion 28 and continuing to the connection electrodes 241 and 242. The quartz diaphragm 2 is conductively bonded onto electrode pads 6 with conductive adhesives S and S reaching both the exposed portions 28 and the first side electrodes 241c and 242c.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a piezoelectric vibration device used as a timing device for various electronic devices.

  In recent years, piezoelectric vibration devices such as crystal resonators and crystal oscillators used in communication equipment and the like have been miniaturized. For example, the external dimensions of a surface-mount type crystal resonator having a substantially rectangular shape in plan view have a long side of 1.0 mm or less and a short side of 0.8 mm or less.

  The crystal unit includes a container having a concave portion opened upward, a quartz crystal plate having a rectangular shape in plan view bonded to the inside of the concave portion via a conductive adhesive, and the like, and a container covering the concave portion. It is constituted by a lid to be joined. Quartz diaphragms used in ultra-compact crystal resonators with the above-described configuration can be accurately shaped by using photolithographic technology and wet etching (etching by chemical dissolution by immersing a quartz wafer in an etchant). Can be molded efficiently.

  A large number of quartz diaphragms are formed from a single artificial quartz wafer (for example, an AT-cut quartz) by a photolithographic technique and wet etching. Since the periphery of the crystal diaphragm is penetrated by wet etching, a connection called a “bridge” is used to connect the support part formed integrally with the frame part around the crystal diaphragm and the crystal diaphragm body. Parts are provided.

  Since AT-cut quartz is an anisotropic material, even when wet etching is performed with a metal pattern having a rectangular opening in plan view, the shape of the quartz diaphragm after wet etching may not be rectangular. In order to prevent this and to make the plan view shape of the quartz crystal plate after wet etching closer to a rectangle, the bridge may be provided at both ends of the side surface on the short side of the quartz crystal plate. The quartz diaphragm main body is separated from the quartz wafer by being broken off from the bridge. For example, Patent Literatures 1 to 3 disclose such a crystal diaphragm.

  A side surface on one short side of the quartz diaphragm, and an inner region with respect to both end portions of the side surface via a conductive adhesive on the electrode pad provided in the concave portion of the container described above A pair of side electrodes to be joined is formed. In order to ensure connection reliability, this side electrode should be provided so as to extend from both end portions of the side surface on the short side to the inner region with respect to the both end portions. Therefore, the formation region of the side electrode of the quartz diaphragm divided from the bridge becomes a minute region.

  When the crystal diaphragm is joined to the electrode pad via a conductive adhesive, the conductive adhesive reaches only the minute side electrode on the side surface of the crystal diaphragm. Furthermore, since the side electrode made of a metal film itself does not have good adhesion with the conductive adhesive, the adhesion between the conductive adhesive and the side electrode is insufficient, and the characteristics of the micro crystal resonator May adversely affect

JP 2008-92505 A Patent No. 4830069 Japanese Patent No. 5152542

  The present invention has been made in view of the above points, and an object of the present invention is to provide a piezoelectric vibration device having a high connection reliability between the container and the piezoelectric vibration plate and having good characteristics even if it is ultra-small. Is.

  In order to achieve the above object, the invention of claim 1 is a piezoelectric vibration device in which a piezoelectric diaphragm is joined to an electrode pad provided on a container via a conductive adhesive, and the piezoelectric diaphragm is a flat surface. A pair of excitation electrodes facing each other is formed on each central side of the front and back main surfaces, and connection electrodes drawn out from each of the pair of excitation electrodes to at least one short side of the piezoelectric diaphragm are Formed on the side surface on the one short side of the piezoelectric diaphragm is an exposed portion where the substrate of the piezoelectric diaphragm is exposed, and a first side electrode adjacent to the exposed portion and continuing to the connection electrode. The piezoelectric diaphragm is conductively bonded onto the electrode pad in a state where the conductive adhesive reaches both the exposed portion and the first side electrode.

  According to the above invention, since the piezoelectric diaphragm is conductively bonded on the electrode pad in a state where the conductive adhesive extends not only to the first side electrode but also to the exposed portion, the piezoelectric diaphragm and the conductive adhesive are bonded. Adhesive strength with the agent can be improved. This is because the bonding force can be supplemented by the piezoelectric diaphragm base having excellent adhesion to the conductive adhesive.

  In order to achieve the above object, the invention according to claim 2 is a piezoelectric vibration device in which a piezoelectric diaphragm is joined to an electrode pad provided on a container via a conductive adhesive, and the piezoelectric diaphragm Is a substantially rectangular shape in plan view, and a pair of exciting electrodes facing each other is formed on each central side of the front and back main surfaces, and a connection is drawn from each of the pair of exciting electrodes to at least one short side of the piezoelectric diaphragm. An electrode is formed, and on the side surface on the short side of the piezoelectric diaphragm, an exposed portion where the substrate of the piezoelectric diaphragm is exposed is provided, and on the side surface on the long side of one set of the piezoelectric diaphragm, A second side surface electrode adjacent to the exposed portion and continuous to the connection electrode is provided, and the piezoelectric diaphragm extends to both the exposed portion and the second side surface electrode. In this state, the conductive bonding is performed on the electrode pad.

  According to the above invention, the conductive adhesive includes the exposed portion of the side surface on the short side of the piezoelectric diaphragm and the second side surface of the pair of long sides of the piezoelectric diaphragm adjacent to the exposed portion. The piezoelectric diaphragm is conductively bonded onto the electrode pad in a state of reaching any of the side electrodes. That is, since the conductive adhesive reaches two adjacent side surfaces of the piezoelectric diaphragm, the bonding force between the piezoelectric diaphragm and the electrode pad can be further increased.

  In order to achieve the above object, the invention according to claim 3 is characterized in that each side surface on the short side and the long side of the piezoelectric diaphragm includes an inclined surface, and the first side surface electrode and / or the A second side electrode is formed so as to extend from the connection electrode to the inclined surface.

  According to the above invention, the adhesion between the piezoelectric diaphragm and the conductive adhesive can be increased, and the connection reliability can be improved. This includes an inclined surface on each side of the short side and long side of the piezoelectric diaphragm so that the first side electrode and / or the second side electrode extends from the connection electrode to the inclined surface. This is because the angle formed by the plurality of surfaces can be made gentler than the configuration in which the side surface of the piezoelectric diaphragm is perpendicular to the main surface of the piezoelectric diaphragm. Thereby, disconnection of the side electrode can be prevented.

  In order to achieve the above object, according to a fourth aspect of the present invention, the exposed portion is a fracture mark after folding of a bridge formed integrally with the piezoelectric diaphragm and protruding from the piezoelectric diaphragm.

  According to the said invention, the adhesive force of a piezoelectric diaphragm and a conductive adhesive can be improved. This is because the surface of the piezoelectric diaphragm excellent in adhesion with the conductive adhesive is a rupture mark after breaking the bridge, the surface is rough compared to the side of the piezoelectric diaphragm other than the bridge, This is because the adhesion with the conductive adhesive is further improved (so-called “anchor effect”).

  As described above, according to the present invention, it is possible to provide a piezoelectric vibration device having high connection reliability and good characteristics between a container and a piezoelectric vibration plate even if it is ultra-compact.

Schematic cross-sectional view of a crystal resonator according to an embodiment of the present invention Schematic top view of the quartz resonator according to an embodiment of the present invention, with the lid removed. The elements on larger scale before breaking of the crystal diaphragm which concerns on embodiment of this invention Magnified schematic diagram after folding of quartz crystal plate according to an embodiment of the present invention Enlarged perspective view of part B in FIG. The expanded perspective view of the crystal diaphragm which concerns on other embodiment of this invention.

  Hereinafter, a crystal resonator will be described as an example of a piezoelectric vibration device according to an embodiment of the present invention and will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view taken along line AA of FIG. 2 of a crystal resonator according to an embodiment of the present invention. First, the outline of each member constituting the crystal resonator will be described, and then the details of the crystal diaphragm will be described.

  The crystal resonator 1 in the present embodiment is a surface-mount type piezoelectric vibration device made of a substantially rectangular parallelepiped package, and the shape in plan view is substantially rectangular. In this embodiment, the external dimensions of the crystal resonator 1 in plan view are about 1.0 mm for the long side and about 0.8 mm for the short side. The outer dimensions are examples, and the present invention can be applied to other outer dimensions.

  As shown in FIG. 1, the crystal resonator 1 includes a crystal vibrating plate 2 on a pair of projecting portions 5 and 5 projecting from an inner bottom surface 90 of the recess 9 of the container 3 via conductive adhesives S and S. The structure is cantilevered and joined. The crystal diaphragm 2 is hermetically sealed in the package by bonding the lid 4 to the upper surface 300 of the frame-shaped side wall 30 constituting the recess 9 of the container 3 via a sealing material (not shown). Yes.

  The container 3 is a container body having a rectangular shape in plan view using an insulating material as a base material. The container 3 is a fired body of a ceramic green sheet composed of two layers, a lower layer and an upper layer. The upper layer includes a frame-like side wall 30, and a metal film (not shown) is formed in a frame shape on the upper surface 300 of the side wall 30.

  On the inner bottom surface 90 of the recess 9 of the container 3, a pair of projecting portions 5 projecting upward are formed at positions spaced inward from the inner wall surface of the side wall 30. The pair of protrusions 5 and 5 have a rectangular shape in plan view, and as shown in FIG. 2, the long side is parallel to the short side direction (vertical direction in FIG. 2) of the rectangular shape 3 in plan view. In such a manner, they are formed so as to be spaced apart from each other.

  The protrusion 5 is made of the same insulating material as the base material of the container 3, and a conductor film is formed on the upper surface thereof. This conductor film serves as an electrode pad 6 that is conductively bonded to the crystal diaphragm 2 via the conductive adhesive S. In the present embodiment, the electrode pad 6 has a laminated structure in which an electrolytic nickel plating layer is formed on a molybdenum metallization layer and an electrolytic gold plating layer is further formed thereon.

  The pair of electrode pads 6 and 6 includes vias (not shown) filled with conductors in through holes penetrating the inside of the protruding portions 5 and 5 made of an insulating material in the thickness direction, and internal wiring ( The two external connection terminals 8, 8, 8, 8 provided on the outer bottom surface of the container 3 are electrically connected to each other via a not shown). The external connection terminal 8 and the above-described metal film on the upper surface 300 of the side wall 30 are also laminated on the molybdenum metallization layer in the order of a nickel plating layer and a gold plating layer. In addition to molybdenum, tungsten (W) or titanium (Ti) may be used for the metallized layer.

  In the region of the inner bottom surface 90 of the recess 9, the pillow portion 7 is formed at a position corresponding to the lower side of the other end side 2 </ b> B of the crystal diaphragm. The pillow part 7 is made of an insulating material like the protruding part 5, and no conductor film is formed on the upper surface thereof.

  The lid 4 has a configuration in which a plating layer is laminated in the order of a nickel plating layer and a gold plating layer on the outer peripheral surface of Kovar as a base material. A gold-tin alloy (AuSn) is attached to the outer peripheral portion of the surface of the lid 4 on the side to be joined with the container 3 in a frame shape. The gold-tin alloy serves as a sealing material, and the container 3 and the lid 4 are heated by heating the gold-tin alloy and the metal film on the upper surface 300 of the side wall 30 of the container 3 to a predetermined temperature. Is welded.

  The crystal diaphragm 2 shown in FIG. 2 is an AT-cut crystal diaphragm and has a rectangular shape in plan view. The quartz crystal plate 2 includes a vibrating portion 20 in a thick area where excitation electrodes (described later) are formed, and a thin portion 21 that is thinner than the vibrating portion 20 around the vibrating portion 20. The vibration part 20 is formed slightly smaller than the thin part 21 in plan view. Such a cross-sectional shape of the quartz crystal plate 2 is a so-called “bi-mesa shape” in which the center portions of the front and back main surfaces of the quartz plate are protruded in the thickness direction. The shape of the crystal diaphragm is not limited to the “bi-mesa shape”. For example, a so-called “reverse mesa shape” including a flat plate shape or an outer peripheral portion formed thicker than the vibration portion on the center side may be used. Moreover, the structure by which only one main surface side of the quartz-crystal diaphragm was thinned may be sufficient. The external shape of such a crystal diaphragm is formed by using an AT-cut crystal wafer by photolithography and wet etching.

  Excitation electrodes for driving the crystal diaphragm are provided on the center side of one main surface (front surface in FIG. 1) of the crystal diaphragm 2 and the other main surface (back surface in FIG. 1) facing the one main surface. 22a and 22b are formed in a pair so as to face each other. In FIGS. 1 to 6, “a” is appended to the end of the reference sign for various electrodes on the one main surface side of the crystal diaphragm 2, and “b” is attached to the end of the reference sign for the various electrodes on the other main face side of the crystal diaphragm 2. Is used to distinguish the electrodes on the front and back of the quartz diaphragm.

  From each of the pair of excitation electrodes 22a and 22b, extraction electrodes 23a and 23b are formed that are extracted in the same direction. A pair of connection electrodes 241 and 242 connected to the terminal ends of the extraction electrodes 23a and 23b and conductively joined to the pair of electrode pads 6 and 6 of the container 3 are connected to one end side 2A of the quartz crystal diaphragm 2, respectively. Is formed.

  One of the connection electrodes 241 is partly connected to one main surface via a short side surface on one end side 2A of the crystal diaphragm 2 from a connection electrode 241b (see FIG. 1) on the other main surface of the crystal diaphragm 2. It is connected to the connection electrode 241a. Similarly, the other connection electrode 242 is partially connected to the other main surface from the connection electrode 242a on one main surface of the quartz crystal plate 2 via the short side surface on one end side 2A of the crystal plate 2. It is connected to the electrode 242b (not shown in FIG. 2). The pair of connection electrodes 241 and 242 have different polarities.

  The electromechanical connection between the pair of electrode pads 6 and 6 of the container 3 and the connection electrodes 241b and 242b on the other main surface of the quartz crystal plate 2 is performed through the conductive bonding materials S and S. In the present embodiment, a silicone resin adhesive is used as the conductive bonding material S. The conductive bonding material S is an adhesive in which a metal filler is contained in a silicone resin, and is cured in a drying furnace controlled to a predetermined temperature profile after application. The application to the present invention is not limited to silicone resin adhesives.

  The conductive adhesives S and S are discharged and applied from the dispenser onto the upper surfaces of the pair of electrode pads 6 and 6 using image recognition means. Then, the quartz diaphragm 2 is positioned and placed with respect to the conductive adhesives S and S applied to the upper surfaces of the pair of electrode pads 6 and 6. After the crystal diaphragm 2 is positioned and placed on the conductive adhesives S, S, the conductive adhesives S, S are expanded by the weight of the crystal diaphragm 2 and the downward pushing operation.

  As shown in FIG. 2, each outer edge of the conductive adhesives S, S in the extending direction of the short side of the quartz diaphragm 2 (vertical direction in FIG. 2) is one end side 2A of the quartz diaphragm 2 in plan view. It is located inside the short corners C1 and C1 (in the central direction of one short side in FIG. 2).

  As described above, since the conductive adhesives S and S are located inside the both corners C1 and C1 of one short side of the crystal diaphragm 2, the stress transmitted from the container 3 bonded to the external substrate is crystal. The influence transmitted to the diaphragm 2 can be suppressed. Thereby, stability of the oscillation frequency of the crystal unit 1 can be improved. In addition, the application position of the conductive adhesive in a plan view on the quartz diaphragm in the present invention is not limited to the inside with respect to both corners of one short side of the quartz diaphragm. That is, the outer edge of the conductive adhesive may extend outward beyond both corners of one short side of the quartz diaphragm.

  Next, details of the quartz crystal diaphragm according to the embodiment of the present invention will be described. A large number of quartz diaphragms 2 can be obtained from a single AT-cut quartz diaphragm wafer (hereinafter abbreviated as quartz wafer) by using photolithography and wet etching.

  FIG. 3 is an enlarged schematic top view of a region including a unit of quartz crystal plate whose outer shape is formed from a quartz wafer. In FIG. 3 and FIGS. 4 to 6 described later, the direction of the crystal axis of the AT-cut quartz crystal diaphragm is indicated by an arrow. A pair of bridges (connecting portions) 25 and 25 are formed from both ends of one short side of one unit of the crystal diaphragm 2 so as to protrude toward the linear support portion 29 in the crystal wafer. As described above, by forming the pair of bridges so as to protrude from both end portions of one short side of the quartz crystal plate 2, the plan view shape of the quartz plate after the wet etching can be made substantially rectangular. When the bridge is formed at a position that is one short side of the crystal diaphragm and does not include both end portions of the short side (for example, the central portion of the short side), wet etching is performed due to the crystal anisotropy of the AT cut crystal. The shape of the later quartz diaphragm may not be rectangular. This is a phenomenon in which the width (short side length) of the crystal diaphragm gradually decreases as it approaches the end on the side where the bridge is formed in the X-axis direction (long side direction) of the AT cut crystal (so-called “ Side etching "). On the other hand, by forming the bridge so as to protrude from both end portions of one short side of the quartz crystal plate, the plan view shape of the quartz crystal plate can be made substantially rectangular.

  The crystal diaphragm including the bridge 25 and the support portion 29 shown in FIG. 3 is formed by immersing (wet etching) a crystal wafer having a predetermined region masked with a metal film in an etching solution. It is formed by passing through a region other than the region. Then, the quartz crystal diaphragm 2 is folded from the pair of bridges 25, 25, so that the quartz crystal diaphragm 2 in an individual state is obtained.

  The support portion 29 in FIG. 3 is integrally formed with a crystal diaphragm 2 and a pair of bridges 25, 25 from a single crystal wafer. A plurality of support portions 29 are formed to extend in parallel with the short sides of the crystal diaphragm 2 having a rectangular shape in plan view so as to connect a pair of opposing sides constituting the outer frame of the crystal wafer having a rectangular shape in plan view. Yes. The plurality of support portions 29, 29,..., 29 are formed in alignment in the quartz wafer so as to be parallel to each other with a predetermined interval.

  Slits 26 and 26 for facilitating the folding of the crystal diaphragm from the bridge are formed at the connection portion of the pair of bridges 25 and 25 with the crystal diaphragm 2. The pair of slits 26, 26 are provided in parallel with the short side direction (Z′-axis direction in FIG. 3) of the crystal diaphragm from the inner surface to the outer surface of the pair of bridges 25, 25 in plan view. Yes. The slit 26 is formed with a length that does not reach from the inner surface to the outer surface of the bridge in the width direction (Z′-axis direction) of the bridge 25. Further, the slit 26 is thinned to a depth of about half of the thickness of the bridge 25 in a cross-sectional view. In the embodiment of the present invention, the slit is formed only on one side of the bridge, but the slit may be formed on both sides (both main surfaces) of the bridge. When forming slits on both sides of the bridge, the slit formation depth may be different between the front and back sides of the bridge.

  On the front and back main surfaces of the bridge 25, a pair of lead-out electrodes (reference numerals omitted) drawn from each of the pair of connection electrodes 241 and 242 are formed. The ends of the pair of lead-out electrodes are connected to a pair of measurement pads (electrodes) formed on the front and back main surfaces of the support portion 29, respectively. This pair of measurement pads is an electrode for measuring the frequency of each crystal diaphragm in the crystal wafer.

  The lead-out electrode and the pair of measurement pads are collectively formed by sputtering together with the pair of excitation electrodes 22a and 22b, the extraction electrodes 23a and 23b, and the pair of connection electrodes 241 and 242 of the crystal diaphragm. Specifically, these electrodes have a film configuration in which chromium (Cr) or titanium (Ti) is used as a base layer and gold (Au) is formed thereon. Note that the material of the base layer and the upper layer of these electrodes is not limited to chromium or gold. During the sputtering, Cr and Au ejected from the target enter into the pair of slits 26, 26, so that the metal film 27 (271, 272) in the slit continues to the pair of connection electrodes 241, 242. Formed.

  FIG. 4 is an enlarged schematic view showing a state after the crystal diaphragm shown in FIG. 3 is broken from the pair of bridges 25 and 25. The crystal diaphragm 2 is divided from the pair of bridges 25 and 25 in a state where the surface on which the slits 26 and 26 are formed is a lower surface, the free end side of the crystal diaphragm 2 (X-axis direction in FIG. 3). This is performed by applying mechanical stress from the lower side to the upper side of the lower surface (near the terminal end). In addition, the said form of a division | segmentation is an example, You may divide | segment a crystal diaphragm by applying mechanical stress to the free end side of the surface in which the slit of a crystal diaphragm is not formed.

  FIG. 5 is an enlarged perspective view of a portion B in FIG. 4, and is an enlarged perspective view of only the peripheral region including the connection electrode 242 of the crystal diaphragm 2 after being broken from the bridge. As shown in FIG. 5, the connection electrodes 242a and 242b constituting the connection electrode 242 are opposed to each other on the front and back of the crystal diaphragm, and have the same size. In addition, for convenience of explanation of the application state of the conductive adhesive, the application position of the conductive adhesive is indicated by a broken line (illustration of the electrode pad 6 of the container is omitted).

  First side electrodes 241c and 242c are formed near both ends of the side surface on one short side of the quartz-crystal diaphragm 2 having a rectangular shape in plan view. The first side electrodes 241 c and 242 c extend over the entire thickness direction of the side surface on the short side of the crystal diaphragm 2. That is, the first side electrode 241c is formed continuously with the connection electrode 241 (241a, 241b), and the first side electrode 242c is formed continuously with the connection electrode 242 (242a, 242b). Yes.

  The breaking marks (fracture surfaces) 28 and 28 of the marks broken from the bridges 25 and 25 are rougher than a region where the bridge on the side surface on the short side of the quartz diaphragm is not formed. . The portion other than the break mark 28 on the side surface on the short side of the quartz diaphragm is the crystal plane of the AT-cut quartz that appears by wet etching, and the surface thereof is smooth due to chemical erosion. On the other hand, the breaking mark 28 is a cleavage plane in which the bridge is broken by mechanical stress. Therefore, the smoothness of the surface of the folding mark 28 is relatively rough compared to the portion other than the folding mark 28 on the side surface on the one short side. The folding mark 28 is an “exposed portion” where the base of the crystal diaphragm is exposed.

  Since the exposed portion is a fracture mark after the breakage of the bridges 25 and 25 formed integrally with the crystal diaphragm 2 and protruding from the crystal diaphragm 2, the crystal diaphragm 2 and the conductive adhesive S are in close contact with each other. The power can be improved. This is because the base of the quartz diaphragm 2 having excellent adhesion to the conductive adhesive S is a fracture mark after the bridge 25 is broken, and the surface thereof is rough compared to the side of the quartz diaphragm other than the bridge. This is because the adhesion with the conductive adhesive S is further improved (anchor effect).

  In the embodiment of the present invention, as shown in FIG. 5, the quartz diaphragm 2 is in a state where the conductive adhesives S, S extend to both the exposed portion (the folding mark 28) and the first side electrode 242 c. And conductively bonded on an electrode pad (not shown). Specifically, in the embodiment of the present invention, the quartz diaphragm 2 includes the exposed portions (28, 28) of the conductive adhesives S, S, the first side electrodes 241c, 242c, and the metal film 271 in the slit. , 272 are conductively bonded on the electrode pads 6 and 6.

  According to the above configuration, in the state where the conductive adhesive S reaches not only the first side surface electrodes 241c and 242c but also the exposed portion (28), the crystal diaphragm 2 is connected to the pair of electrode pads 6 and 6. Since the conductive bonding is performed on the top, the adhesion between the quartz crystal plate 2 and the conductive adhesive S can be improved. This is because the bonding force can be supplemented by the base of the quartz diaphragm 2 having excellent adhesion with the conductive adhesive S.

-Other embodiments of the present invention-
Next, another embodiment of the present invention will be described with reference to FIG. FIG. 6 is an enlarged perspective view of only the peripheral region including the connection electrode 132 of the quartz crystal plate 10 after being broken off from the bridge. In addition, about the structure similar to embodiment of this invention mentioned above, the description is omitted using the same code | symbol. Hereinafter, the difference from the above-described embodiment of the present invention will be mainly described.

  In another embodiment of the present invention, the shape of the quartz diaphragm and the application form of the conductive adhesive are different from the above-described embodiments of the present invention. First, regarding the shape of the crystal diaphragm, as shown in FIG. 6, inclined surfaces 11 (11 a, 11 b) appear on each of a pair of long side surfaces of the crystal diaphragm 10. In addition, inclined surfaces 12 (12a, 12b) also appear on each of the pair of short side surfaces of the crystal diaphragm 10. Regarding the inclined surface 11 on the side surface on the long side of the quartz crystal plate 10, the angle α formed between the inclined surface 11a and one main surface (the lower main surface in FIG. 6) of the crystal plate 10 is an obtuse angle. It has become. Further, the angle β formed between the inclined surface 11a and the inclined surface 11b is also an obtuse angle. On the other hand, regarding the inclined surface 12 on the side surface on the short side of the quartz crystal plate 10, an angle γ formed between the inclined surface 12a and one main surface (the lower main surface in FIG. 6) of the crystal plate 10, and The angle δ formed between the inclined surface 12a and the inclined surface 12b and the angle ε formed between the inclined surface 12b and the other main surface of the quartz crystal plate 10 (the upper main surface in FIG. 6) are all obtuse angles. Yes. In addition, regarding the inclined surfaces of the side surface on the long side and the side surface on the short side of the crystal diaphragm, the angle formed between the main surface of the crystal diaphragm and the inclined surface continuous thereto, or between the inclined surfaces Since the angles vary depending on the etching conditions, all of these angles are not necessarily obtuse, and obtuse angles and acute angles may be mixed.

  The inclined surfaces 11a and 11b and the inclined surfaces 12a and 12b are crystal surfaces of AT-cut quartz that appeared by wet etching, and the number of appearances and the angle formed between the inclined surfaces change depending on the etching conditions, so that the quartz crystal diaphragm The shape of the can change. Therefore, the appearance of the inclined surface of the crystal diaphragm shown in FIG. 6 is merely an example, and the application of the present invention is not limited to the number of appearances and the side surface shape of the inclined surface of the crystal diaphragm shown in FIG. .

  Further, due to the anisotropy of the AT-cut quartz, there is a difference in the cross-sectional shape at each of both ends in the long side direction and both ends in the short side direction of the quartz crystal plate having a rectangular shape in plan view. In particular, when the X-axis of the AT-cut crystal is set on the long side of the quartz-crystal diaphragm having a rectangular shape in plan view and the Z′-axis of the AT-cut crystal is set on the short side as shown in FIGS. The difference in cross-sectional shape at both ends of the film increases depending on the etching conditions. The AT-cut quartz has such properties, but the application of the present invention is not limited to the crystal axis direction shown in FIGS. 5 to 6, and the Z′-axis is located on the long side of the quartz crystal plate having a rectangular shape in plan view. The X axis may be set on the short side.

  Second side surface electrodes 141 (not shown in FIG. 6) and 142 are formed on the inclined surfaces 11 and 11 on the side surfaces of the long side of the pair of quartz crystal plates 10. Specifically, the second side electrode 141 is adjacent to the exposed portion 16 (one of the pair of exposed portions 16 and 16) and is continuous with the connection electrode 131 (131a and 131b, not shown in FIG. 6). Is formed. Similarly, the second side electrode 142 is adjacent to the exposed portion 16 (the other of the pair of exposed portions 16, 16) and is formed continuously with the connection electrode 132 (132a, 132b). Further, first side surface electrodes 131c (not shown in FIG. 6) and 132c are formed on the inclined surface 12 (12a, 12b) on the side surface on one short side of the quartz crystal plate 10.

  In another embodiment of the present invention, a slit is formed in each of the pair of bridges in the state before the bridge is folded, as in the above-described embodiment of the present invention. Therefore, the in-slit metal film 15 (151 (not shown in FIG. 6), 152) is deposited inside each of the pair of slits. The in-slit metal films 15 (151 and 152) are continuously formed on the pair of connection electrodes 131a and 132a, respectively, and are also formed continuously on the adjacent first side electrodes 131c and 132c. .

  Next, as to the application form of the conductive adhesive, as shown in FIG. 6, the conductive adhesive S includes the second side electrodes (141, 142), the exposed portions 16, 16, and the metal film 15 in the slit ( 151, 152).

  According to the above configuration, it is possible to increase the adhesion between the quartz diaphragm 10 and the conductive adhesive S and improve the connection reliability. The pair of long sides of the quartz diaphragm 10 includes inclined surfaces 11 and 11. The second side electrode 141 is formed to extend from the connection electrode 131 (131a, 131b) to the inclined surface 11 (11a, 11b). Similarly, the second side electrode 142 is formed to extend from the connection electrode 132 (132a, 132b) to the inclined surface 11 (11a, 11b). With such a configuration, the angle formed by the plurality of surfaces can be made gentler than in a configuration in which the side surface of the crystal diaphragm is perpendicular to the main surface of the crystal diaphragm. Thereby, disconnection of the side electrode can be prevented.

  Moreover, according to the said structure, the adhesive force of the crystal diaphragm 10 and the electroconductive adhesive S can be improved. This is because the base of the quartz diaphragm 10 having excellent adhesion to the conductive adhesive S is a fracture mark (16) after the bridge is broken off, so that the surface is rougher than the side of the quartz diaphragm other than the bridge. This is because the adhesion with the conductive adhesive S is further improved.

  In the embodiment and other embodiments of the present invention described above, the conductive adhesive S is applied so as to be within the region of the pair of electrode pads 6 and 6 in plan view. However, the application area | region with respect to the electrode pad of a conductive adhesive may protrude from the said area | region not only in the area | region of planar view of a pair of electrode pad. In this case, the conductive adhesive protrudes from the outer edges of the pair of electrode pads toward the side wall on the long side of the container, and the outer surface of the protrusion and / or the inner bottom surface (base) of the container recess and the container You may reach the area | region between the side walls on the long side. In the case of such an application form of the conductive adhesive, a part of the conductive adhesive is in contact with the side surface of the projecting portion which is the insulating material and / or the inner bottom surface of the concave portion which is the insulating material, so that the bonding strength is further increased. Can be improved. Thereby, it is possible to further improve the connection reliability between the container and the crystal diaphragm in the ultra-small crystal resonator.

  In the above-described embodiment of the present invention and other embodiments, the crystal diaphragm is conductively bonded onto the electrode pad on the upper surface of the protrusion in a cantilever state. However, the protrusion or step is also formed on the free end side of the crystal diaphragm. A portion may be formed and conductive bonding may be performed in a both-sided state. Further, in the above-described embodiment of the present invention and other embodiments, the number of connections for electrically bonding the crystal diaphragm and the container is two, but the number of connections is not limited to two, There may be two or more. Further, the number of bridges formed on one crystal diaphragm is not limited to two, and for example, two or more bridges may be formed.

  In the above-described embodiment of the present invention and other embodiments, the conductive adhesive is applied so as to straddle the upper surface of the pair of electrode pads, the exposed portion, and the first side electrode or the second side electrode. However, the conductive adhesive may be applied so as to straddle both the upper surface of the pair of electrode pads and the first side surface electrode and the second side surface electrode with the exposed portion interposed therebetween.

  In the above-described embodiments of the present invention and other embodiments, the conductive adhesive is applied only once to the upper surfaces of the pair of electrode pads (so-called “undercoating”). A conductive adhesive may be further applied over the adhesive (so-called “overcoating”).

  The main surface bonded to the electrode pad of the crystal diaphragm is not limited to one main surface (lower surface) of the crystal diaphragm shown in FIGS. 5 to 6, but the other main surface (upper surface) of the crystal diaphragm. It may be on the side.

  In the above-described embodiment of the present invention, the piezoelectric vibrator is exemplified by the quartz vibrator in which only the quartz diaphragm is accommodated in the container. However, the present invention is not limited to the quartz vibrator having the configuration, and the container is a temperature sensor. It can also be applied to crystal oscillators with built-in and crystal oscillators.

  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 vibration devices.

DESCRIPTION OF SYMBOLS 1 Quartz crystal resonator 2, 10 Quartz diaphragm 3 Container 4 Lid 6 Electrode pad 11, 12 Inclined surface 131c, 132c, 241c, 242c 1st side electrode 141, 142 2nd side electrode 16, 28 Exposed part 25 Bridge S Conductive adhesive

Claims (4)

A piezoelectric vibration device in which a piezoelectric vibration plate is bonded to an electrode pad provided on a container via a conductive adhesive,
The piezoelectric diaphragm is substantially rectangular in a plan view, and a pair of excitation electrodes facing each other is formed on each central side of the front and back main surfaces, and at least one short side of the piezoelectric diaphragm from each of the pair of excitation electrodes A connection electrode to be drawn out is formed,
On the side surface on the one short side of the piezoelectric diaphragm, an exposed portion where the substrate of the piezoelectric diaphragm is exposed, and a first side electrode adjacent to the exposed portion and continuing to the connection electrode are provided,
The piezoelectric vibration device, wherein the piezoelectric vibration plate is conductively bonded on the electrode pad in a state where the conductive adhesive extends to both the exposed portion and the first side electrode. A piezoelectric vibration device in which a piezoelectric vibration plate is bonded to an electrode pad provided on a container via a conductive adhesive,
The piezoelectric diaphragm is substantially rectangular in a plan view, and a pair of excitation electrodes facing each other is formed on each central side of the front and back main surfaces, and at least one short side of the piezoelectric diaphragm from each of the pair of excitation electrodes A connection electrode to be drawn out is formed,
An exposed portion in which the substrate of the piezoelectric diaphragm is exposed is provided on the side surface on the one short side of the piezoelectric diaphragm, and the side surface on the long side of one set of the piezoelectric diaphragm is adjacent to the exposed portion. A second side electrode continuous to the connection electrode is provided;
The piezoelectric vibration device, wherein the piezoelectric vibration plate is conductively bonded on the electrode pad in a state where the conductive adhesive extends to both the exposed portion and the second side electrode.   Each side surface on the short side and the long side of the piezoelectric diaphragm includes an inclined surface, and the first side electrode and / or the second side electrode extends from the connection electrode to the inclined surface. The piezoelectric vibration device according to claim 1, wherein the piezoelectric vibration device is formed.   4. The piezoelectric device according to claim 1, wherein the exposed portion is a fracture mark after breaking of a bridge formed integrally with the piezoelectric diaphragm and protruding from the piezoelectric diaphragm. 5. Vibration device.

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