JP2005198237A - Piezoelectric vibration device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric vibration device which has high versatility, can be miniaturized without reducing the electrical characteristics of piezoelectric vibration element, and is capable of holding the piezoelectric vibration element, either by one side or by both sides. <P>SOLUTION: The piezoelectric vibrating device has a base 1 for holding the piezoelectric vibrating element 3 and a cap 2. On the bottom of the inside of the base, electrode pads 14, 15, and 16 are formed at both ends of the short side, as well as at both ends of the long side, respectively. The electrode pads 14 and 15 are electrically independent and extended to a terminal electrode on the bottom of the base, and the electrode pads 14 and 16 are commonly connected, by a connecting electrode and extended to the terminal electrode, located on the bottom of the base. The electrode pads 14 and 16 and an excitation electrode, located on the opposite side of the base of the piezoelectric vibration element, are electrically connected, and the electrode pad 15 and an excitation electrode on the opposite side of the cap of the piezoelectric vibration element are electrically connected. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a piezoelectric vibration device such as a crystal resonator, a crystal filter, a crystal oscillator, and the like, and more particularly, to improve an electrode pad in which a piezoelectric vibration element is mounted on a surface mount package made of a ceramic material or the like. .

  Examples of electronic components that require hermetic sealing include piezoelectric vibration devices such as crystal resonators, crystal filters, and crystal oscillators. In each of these products, a metal thin film electrode is formed on the surface of a crystal diaphragm (piezoelectric vibration element), and the metal thin film electrode is hermetically sealed to protect the metal thin film electrode from the outside air.

Due to the demand for surface mounting of components, these piezoelectric vibration devices are increasingly being housed in a package made of a ceramic material. For example, Patent Document 1 discloses a base (substrate) having a concave cross section having four electrode pads (connection electrodes) on which a quartz diaphragm having excitation electrodes formed on front and back surfaces is mounted, and a cap having a reverse concave shape in cross section. There is disclosed a package made of a ceramic material comprising a (lid) and hermetically sealed. Here, of the four electrode pads, two electrode pads opposed to each other in the long side direction are commonly connected to each other by connection electrodes (metal wirings) so as to have the same potential, so that a pair of electrode pads has two bases. Since the quartz diaphragm is electromechanically bonded to the pair of electrode pads with a conductive bonding material, the assembly workability is considered without considering the direction of mounting. Is to improve. Moreover, if it is a piezoelectric vibration device disclosed in Patent Document 1, it is possible to hold the quartz diaphragm at only one end in the long side direction or both ends at both ends in the long side direction. It is highly versatile.
JP-A-7-235854

  In recent years, the packages used for piezoelectric vibration devices as described above are becoming lighter, thinner, and smaller, and even if the piezoelectric vibration element is downsized, the electrical characteristics such as CI value and frequency sensitivity are not deteriorated. In addition, the excitation electrode is formed as large as possible in the vicinity of the end of the piezoelectric vibration element to ensure an effective area. However, when the piezoelectric vibration element having such a configuration is used in the package of Patent Document 1, there are electrode pads with different potentials in the long side direction or the short side direction, respectively. There is a problem that one of the electrode pads contacts and shorts. In addition, since the excitation electrode of the piezoelectric vibration element is formed so as not to be short-circuited to the electrode pad of the package, not only design dimension restrictions are imposed, but also the electrical characteristics of the piezoelectric vibration element are reduced, and further, the piezoelectric vibration When an element is mounted on a package, it must be formed in consideration of an error such as a shift, and there is a problem that the package is extremely disadvantageous for miniaturization.

  The present invention has been made to solve the above-mentioned problems, and can be used for miniaturization without deteriorating the electrical characteristics of the piezoelectric vibration element. An object of the present invention is to provide a piezoelectric vibration device having high performance.

  According to a first aspect of the present invention, there is provided a piezoelectric vibration device having a rectangular base in plan view for holding a piezoelectric vibration element having excitation electrodes formed on the front and back surfaces, and a cap for hermetically sealing the piezoelectric vibration element. In the piezoelectric vibration device, three electrode pads are formed on the bottom surface inside the base, and the first electrode pad and the second electrode pad facing each other in a specific side direction among the three electrode pads. Are extended to the terminal electrode of the base in an electrically independent state, and the first electrode pad and the third electrode pad facing each other in a direction orthogonal to the specific side direction are commonly connected by the connection electrode. The first electrode pad or the third electrode pad and the excitation electrode on the base-opposing side of the piezoelectric vibration element are electrically connected to each other, and the second electrode Pad and front Characterized in that the excitation electrode of the cap opposite side of the piezoelectric vibrating element is electrically connected.

  According to a second aspect of the present invention, there is provided a piezoelectric vibration device having a rectangular base in plan view for holding a piezoelectric vibration element having excitation electrodes formed on the front and back surfaces, and a cap for hermetically sealing the piezoelectric vibration element. In the piezoelectric vibration device, four electrode pads are formed on the bottom surface inside the base, and among the four electrode pads, a first electrode pad and a second electrode pad facing in a specific side direction are provided. A state in which the first electrode pad and the third electrode pad, which extend to the terminal electrode of the base in an electrically independent state and are opposed to each other in a direction orthogonal to the specific side direction, are commonly connected by the connection electrode And the fourth electrode pad which is opposed to the third electrode pad in a specific side direction is not extended to the base terminal electrode. Power of The pad or the third electrode pad and the excitation electrode on the opposite side of the base of the piezoelectric vibration element are electrically connected, and the second electrode pad and the excitation electrode on the opposite side of the cap of the piezoelectric vibration element are electrically connected It is characterized by being connected to.

  Further, in the above-described configuration, the base is made of a ceramic material, the electrode pad is formed by metallization, and an upper portion of the electrode pad extending to the terminal electrode is made of the same material as the electrode pad. A bump is provided, and the bump is formed at a position where it does not overlap with the excitation electrode on the base facing side of the piezoelectric vibration element.

  Further, in the above-described configuration, the base is made of a ceramic material, and includes a support base for holding the piezoelectric vibration element on an upper surface. The electrode pad is formed by metallization on the support base, and at least The electrode pad formed on the support base on which the piezoelectric vibration element is not held is formed in a state of being separated from the ridge line on the base center side of the support base.

  In the above structure, the second electrode pad is connected to a connection electrode connected to the first electrode pad and a dummy connection electrode having substantially the same area.

  According to claim 1 of the present invention, by electrically connecting the pair of excitation electrodes of the piezoelectric vibration element to the first electrode pad and the second electrode pad formed in a specific side direction of the base, The piezoelectric vibration element can be held in a cantilever manner. Further, by electrically connecting the pair of excitation electrodes of the piezoelectric vibration element to the second electrode pad and the third electrode pad formed in a direction orthogonal to a specific side direction of the base, the piezoelectric vibration element is Since it can be held at both ends, it becomes a more versatile piezoelectric vibration device.

  Further, since the first electrode pad or the third electrode pad and the excitation electrode on the opposite side of the base of the piezoelectric vibration element are electrically connected, the piezoelectric vibration element can be held in a cantilever manner or both supported. Even if either the first electrode pad or the third electrode pad is in contact with the excitation electrode on the opposite side of the base of the piezoelectric vibration element, it extends to the terminal electrode at the same potential. Is not short-circuited. Accordingly, the oscillation of the piezoelectric vibration element is never stopped due to the short circuit. Furthermore, even if the size of the piezoelectric vibration element is limited as the package size is reduced, the adverse effect of displacement when the piezoelectric vibration element is mounted on the package is eliminated, and there is no short circuit. Highly reliable piezoelectric vibration that can be formed by enlarging the excitation electrode of the piezoelectric vibration element in the direction of the side or the direction perpendicular to the specific side direction, which can further improve the electrical characteristics of the piezoelectric vibration element Become a device.

  According to claim 2 of the present invention, by electrically connecting the pair of excitation electrodes of the piezoelectric vibration element to the first electrode pad and the second electrode pad formed in a specific side direction of the base, The piezoelectric vibration element can be held in a cantilever manner. Further, by electrically connecting the pair of excitation electrodes of the piezoelectric vibration element to the second electrode pad and the third electrode pad formed in a direction orthogonal to a specific side direction of the base, the piezoelectric vibration element is Since it can be held at both ends, it becomes a more versatile piezoelectric vibration device. In addition, since the piezoelectric vibration elements are mounted on the first electrode pad, the second electrode pad, the third electrode pad, and the fourth electrode pad formed at the four corners of the inner bottom surface of the base, inclination or the like is generated. Therefore, the piezoelectric vibration element can be held in a more stable state.

  Further, only the fourth electrode pad does not extend to the terminal electrode, and the first electrode pad or the third electrode pad and the excitation electrode on the side opposite to the base of the piezoelectric vibration element are electrically connected. Therefore, the piezoelectric vibration element is held in a cantilever manner or both ends, and the excitation electrode on the opposite side of the base of the piezoelectric vibration element serves as the first electrode pad, the third electrode pad, or the fourth electrode. Even if any of the electrode pads is in contact with each other, they are extended to the terminal electrode in the same potential state or do not have a potential, so there is no short circuit. Accordingly, the oscillation of the piezoelectric vibration element is never stopped due to the short circuit. Furthermore, even if the size of the piezoelectric vibration element is limited as the package size is reduced, the adverse effect of displacement when the piezoelectric vibration element is mounted on the package is eliminated, and there is no short circuit. Highly reliable piezoelectric vibration that can be formed by enlarging the excitation electrode of the piezoelectric vibration element in the direction of the side or the direction perpendicular to the specific side direction, which can further improve the electrical characteristics of the piezoelectric vibration element Become a device.

  According to the third aspect, in addition to the above-described effects, the bump is formed on the electrode pad extending to the terminal electrode at a position not overlapping the excitation electrode on the side facing the base of the piezoelectric vibration element. Therefore, even if either the first electrode pad or the third electrode pad is electrically connected to the excitation electrode on the opposite side of the base of the piezoelectric vibration element, the other is not connected to the excitation electrode on the opposite side of the base There is no contact between the electrode pad and the excitation electrode on the side opposite to the base. Further, the excitation electrode on the opposite side of the base of the piezoelectric vibration element does not come into contact with the base at all. For this reason, even if an external impact is applied to the piezoelectric vibrating device and the piezoelectric vibrating element is bent, no oscillation or the like is caused. In addition, the bumps are stacked on top of an electrode pad made of the same material metallized and integrally fired to form bumps with high adhesion, and can be formed at the same time, making it extremely easy and efficient. Can be formed. Further, when the piezoelectric vibration element is connected with the conductive bonding material, the conductive bonding material accumulates in the gap portion lifted by the bump and the bonding area increases, so that the bonding strength between the piezoelectric vibration element and the base electrode pad is further increased. be able to.

  According to the fourth aspect of the invention, in addition to the above-described effects, the electrode pad is formed by metallization on the upper portion of the support base that holds the piezoelectric vibration element, and at least the support pad that does not hold the piezoelectric vibration element is formed. Since the electrode pad is formed away from the ridge line on the base center side of the support base, contact between the electrode pad formed on the support base on which the piezoelectric vibration element is not held and the excitation electrode on the base-opposing side is performed. Can be suppressed. In addition, the excitation electrode and the base on the opposite side of the base of the piezoelectric vibration element do not come into contact at all due to the gap between the base formed by the support base. For this reason, even if an external impact is applied to the piezoelectric vibrating device and the piezoelectric vibrating element is bent, no oscillation or the like is caused. Furthermore, even if the size of the piezoelectric vibration element is limited due to the downsizing of the package, the adverse effect of the displacement when the piezoelectric vibration element is mounted on the package is further reduced, and the specific side direction of the package, or Since the excitation electrode of the piezoelectric vibration element can be further enlarged and formed in a direction orthogonal to the specific side direction, the electrical characteristics of the piezoelectric vibration element can be further improved.

  According to the fifth aspect, in addition to the above-described effects, the second electrode pad is connected to the connection electrode connected to the first electrode pad and the dummy connection electrode having substantially the same shape. Capacitance values between electrode pads and externally connected terminal electrodes between different base potentials can be approximated, and adverse effects such as slight differences in oscillation frequency depending on the terminal direction can be eliminated. Can do.

  A first embodiment according to the present invention will be described with reference to the drawings by taking a surface-mounted crystal resonator as an example. FIG. 1 is an exploded perspective view of a surface-mounted crystal resonator showing a first embodiment, FIG. 2 is a base plan view of FIG. 1, and FIG. 3 is a bottom view of FIG. 4 is a plan view of a state in which the crystal diaphragm of FIG. 2 is cantilevered, and FIG. 5 is a plan view of a state in which the crystal diaphragm of FIG. The surface-mount type crystal resonator is bonded to a flat rectangular base 1 having a recess having an upper opening, a crystal vibrating plate 3 that is a piezoelectric vibration element housed in the base, and an opening of the base. It consists of a cap 2.

  The base 1 is made of, for example, an alumina ceramic material, and is formed of a rectangular flat plate-shaped base base and a frame body having a large central portion and an outer size substantially equal to the base base. Has been fired. After the firing molding, the glass layer 11a is formed on the upper surface of the frame by a technique such as baking. That is, the base 1 has a shape having a concave piezoelectric vibration element housing portion 10 in cross section, and a circumferential glass layer 11 a is formed on the bank portion 11 around the concave shape. Although the glass layer 11a is not formed, the base and the lid can be hermetically bonded. However, the bonding strength can be improved by forming the glass layer 11a. On the upper and lower parts of the outer periphery of the base, castellations C1 and C2 are formed at the center of both ends in the long side direction, and castellations C3, C4, C5 and C6 are formed at the four corners. Of these, connecting electrodes 121 and 131 are formed below the castellations C1 and C2, and are electrically connected to the terminal electrodes 12 and 13 connected to the outside (see FIG. 3).

  As shown in FIG. 2, three electrode pads 14, 15 and 16 are formed at both ends in the short side direction and at both ends in the long side direction on the bottom surface inside the base. The connection electrodes 121 and 131 and the castellations C1 and C2 are electrically extended to the terminal electrodes 12 and 13 formed on the bottom surface of the base 1. Then, the first electrode pad 14 and the second electrode pad 15 opposed in the short side direction are electrically extended independently to the terminal electrode 13 or the terminal electrode 12 on the bottom surface of the base so that they can be applied with different potentials. The first electrode pad 14 and the third electrode pad 16 opposed in the long side direction are connected in common by the connection electrode 140 so that they can be applied at the same potential, and are extended to the terminal electrode 13 on the bottom surface of the base. Has been. The second electrode pad 15 is connected to a dummy connection electrode 150 having substantially the same area and shape as the connection electrode 140 connected to the first electrode pad. These terminal electrodes, connection electrodes, electrode pads, connection electrodes, dummy connection electrodes are formed by firing integrally with the base after printing a metallized material such as dungsten, molybdenum, etc. Nickel plating is formed on the metallized upper part, and gold plating is formed on the upper part.

  In FIG. 2, the third electrode pad 16 is formed on the bottom surface inside the base at the other end in the long side direction and over the entire short side direction. However, as shown in FIG. Further, it may be formed in a part in the short side direction. In addition, as shown in FIG. 6B, the third electrode pad 16 is formed on the bottom surface inside the base at the other end in the long side direction and at one end portion in the short side direction. 3 may be configured to have an insulating pad Z that is opposed to the third electrode pad in the short side direction and is formed with substantially the same thickness (height) as the third electrode pad. This insulating pad is formed by printing only an insulating paste material such as alumina ceramic and then firing it integrally with the base, or by printing a metallized material such as dungsten or molybdenum and firing it integrally with the base. In addition, an insulating film such as alumina ceramic may be formed on the metallized upper portion.

  Bumps 141, 151, 161 made of the same material as the electrode pads are formed on the electrode pads 14, 15, 16 extending to the terminal electrodes. As shown in FIG. 4 or FIG. 5, these bumps are in contact with the outer peripheral end of the quartz crystal plate 3 to be described later and are not in direct contact with the excitation electrode (base facing side) 32 on the back surface side (positions that do not overlap). ). In the case of this embodiment, the bumps 141 and 151 are formed in an approximately L shape, and the bump 161 is formed in an approximately U shape so that the excitation electrode of the crystal diaphragm is formed to be enlarged in the long side direction and the short side direction. In addition, the crystal vibration plate can be mounted in a shape corresponding to the outer peripheral end of the rectangular crystal vibration plate 3 without the bump reaching the rectangular excitation electrode (base facing side) region. When these bumps are formed, the electrode pad metallization is printed and formed, and after the electrode pad metallization is dried, the electrode pad and the bump are formed by printing according to the shape of the bump. They are formed simultaneously by firing integrally in a laminated state, and the nickel plating as described above is formed also on these metallized upper parts, and gold plating is formed on the upper parts.

  A rectangular crystal diaphragm 3 is mounted on the electrode pads 14, 15, 16. A pair of excitation electrodes 31 and 32 are formed on the front and back surfaces of the quartz diaphragm 3, and are in contact with the quartz diaphragm 3 in the order of chromium, gold, or in the order of chromium, gold, chromium, or chromium, silver, chromium, for example. Electrodes are formed in order.

  When the quartz diaphragm 3 is cantilevered, as shown in FIG. 4, the excitation electrodes 31 and 32 of the quartz diaphragm are drawn in the direction of the electrode pads 14 and 15 of the base 2, and the quartz diaphragm The electrode portion 14 and the electrode pads 14 and 15 are conductively bonded by, for example, a silicone-based conductive bonding material D. At this time, the first electrode pad 14 of the base and the excitation electrode (base facing side) 32 on the back surface side of the quartz crystal diaphragm are electrically connected, and the second electrode pad 15 of the base and the quartz crystal vibration are connected. An excitation electrode (cap facing side) 31 on the surface side of the plate is electrically connected. In addition, as described above, when the first and second electrode pads and the quartz diaphragm are joined by the conductive bonding material, the third electrode pad and the quartz diaphragm are electrically machined with a certain distance therebetween. It functions as a pillow without being joined.

  Further, when the quartz diaphragm 3 is held at both ends, as shown in FIG. 5, the excitation electrodes 31 and 32 of the quartz diaphragm are drawn out toward the electrode pads 15 and 16 of the base 2, and the quartz crystal The electrode portion from which the diaphragm is drawn out and the electrode pads 15 and 16 are conductively bonded by, for example, a silicone-based conductive bonding material D. At this time, the third electrode pad 16 of the base and the excitation electrode (base facing side) 32 on the back surface side of the quartz crystal plate are electrically connected, and the second electrode pad 15 and the quartz plate of the quartz plate are connected. A surface-side excitation electrode (cap facing side) 31 is electrically connected. In addition, as described above, when the second and third electrode pads and the quartz diaphragm are joined by the conductive bonding material, the first electrode pad and the quartz diaphragm are electrically machined with a certain distance therebetween. It functions as a pillow without being joined.

  The cap 2 that hermetically seals the base has a flat plate shape, for example, and is made of an alumina ceramic material or a ceramic glass material. Although not shown in the drawing, the cap 2 is formed with, for example, a lead-based, bismuth-based, or tin phosphate-based low-melting glass material as a sealing bonding material, and the glass material is a base bank portion. Is formed on the cap 2 in a circumferential shape so as to protrude from the electronic element storage portion 10 inwardly of the base. Thereby, an inner meniscus can be created after heating.

  In joining the base and the cap, the glass material formed on the cap is melted and hermetically sealed by heating at a predetermined temperature. In this hermetic sealing operation, in order to perform cap positioning and self-weight sealing, a pallet provided with storage portions in a matrix shape may be used and batch processing may be performed for a large number. Note that a weighted weight may be mounted on the base 1 to promote the bonding between the base and the cap. Moreover, in the said embodiment, although the glass joining material is formed in both joining area | regions of a base and a cap, you may form only in one of a base or a cap. This completes the surface-mount crystal unit.

  Next, a second embodiment of the present invention will be described with reference to the drawings by taking a surface-mount type crystal resonator as an example. 7 is an exploded perspective view of the surface-mount type crystal resonator showing the second embodiment, FIG. 8 is a base plan view of FIG. 7, and FIG. 9 is a bottom view of FIG. FIG. 10 is a plan view of a state in which the crystal diaphragm of FIG. 7 is cantilevered, and FIG. 11 is a plan view of a state in which the crystal diaphragm of FIG. In addition, the same part as 1st Embodiment attaches the same number, and omits a part of description.

  As shown in FIGS. 8 and 9, four electrode pads 14, 15, 16, and 17 are formed at both ends in the short side direction and at both ends in the long side direction on the bottom surface inside the base. The electrode pads are electrically extended to the terminal electrodes 12 and 13 formed on the bottom surface of the base 1 through the connection electrodes 121 and 131 and the castellations C1 and C2. Then, the first electrode pad 14 and the second electrode pad 15 opposed in the short side direction are electrically extended independently to the terminal electrode 13 or the terminal electrode 12 on the bottom surface of the base so that they can be applied with different potentials. The first electrode pad 14 and the third electrode pad 16 opposed in the long side direction are connected in common by the connection electrode 140 so that they can be applied at the same potential, and are extended to the terminal electrode 13 on the bottom surface of the base. Has been. The second electrode pad 15 is connected to a dummy connection electrode 150 having substantially the same area and shape as the connection electrode 140 connected to the first electrode pad. The fourth electrode pad 17 facing the third electrode pad in the short side direction is a first terminal group connected to the first and third electrode pads, and a second terminal connected to the second electrode pad. The terminal group is not connected to any of the terminal groups and has no potential not extending to the terminal electrode. These terminal electrodes, connection electrodes, electrode pads, connection electrodes, dummy connection electrodes are formed by firing integrally with the base after printing a metallized material such as dungsten, molybdenum, etc. Nickel plating is formed on the metallized upper part, and gold plating is formed on the upper part.

  Bumps 141, 151, 161, 171 made of the same material as the electrode pads are formed on the electrode pads 14, 15, 16, 17. Among these, the bumps 141, 151, 161 formed on the electrode pads extending to the terminal electrodes are in contact with the outer peripheral end portion of the crystal diaphragm 3 described later, as shown in FIG. 10 or FIG. At the same time, it is formed at a position where it does not come into direct contact with the excitation electrode (base facing side) 32 on the back side (position where it does not overlap). In the case of the present embodiment, for the electrode pads 14 and 15 on one end side in the long side direction that does not reach the region of the excitation electrode of the mounted crystal diaphragm, the bumps 141 and 151 are slightly small rectangles corresponding to the electrode pad shape. The electrode pad 16 on the other end side in the long side direction extending to the excitation electrode region of the mounted crystal diaphragm has a single character shape with the bump 161 biased to the outside of the base. Even if the excitation electrode is formed so as to be enlarged on the other end side in the long side direction, the bump does not reach the region of the rectangular excitation electrode (on the side facing the base), and the outer peripheral end of the rectangular crystal diaphragm 3 The crystal diaphragm can be mounted in a shape corresponding to the part. The bump 171 formed on the electrode pad 17 that does not extend to the terminal electrode has no problem such as a short circuit even if it directly contacts the excitation electrode (base facing side) 32 on the back side. It is preferable to form it at a position where it does not directly contact the excitation electrode (base facing side) 32 (a position where it does not overlap), since the adverse effect on the electrical characteristics becomes lower. For this reason, the bump 171 also has a single-character shape that is biased to the outside of the base in accordance with the shape of the bump 161. When these bumps are formed, the electrode pad metallization is printed and formed, and after the electrode pad metallization is dried, the electrode pad and the bump are formed by printing according to the shape of the bump. They are formed simultaneously by firing integrally in a laminated state, and the nickel plating as described above is formed also on these metallized upper parts, and gold plating is formed on the upper parts.

  A rectangular crystal diaphragm 3 is mounted on the electrode pads 14, 15, 16 and 17. A pair of excitation electrodes 31 and 32 are formed on the front and back surfaces of the quartz diaphragm 3, and are in contact with the quartz diaphragm 3 in the order of chromium, gold, or in the order of chromium, gold, chromium, or chromium, silver, chromium, for example. Electrodes are formed in order.

  When the quartz diaphragm 3 is cantilevered, as shown in FIG. 10, the excitation electrodes 31 and 32 of the quartz diaphragm are drawn out toward the electrode pads 14 and 15 of the base 2, and the quartz diaphragm The electrode portion 14 and the electrode pads 14 and 15 are conductively bonded by, for example, a silicone-based conductive bonding material D. At this time, the first electrode pad 14 of the base and the excitation electrode (base facing side) 32 on the back surface side of the quartz crystal diaphragm are electrically connected, and the second electrode pad 15 of the base and the quartz crystal vibration are connected. An excitation electrode (cap facing side) 31 on the surface side of the plate is electrically connected. In addition, as described above, when the first and second electrode pads and the quartz diaphragm are joined by the conductive bonding material, the third and fourth electrode pads and the quartz diaphragm have a certain interval. It functions as a pillow material without being electrically and mechanically joined.

  Further, when the quartz diaphragm 3 is held at both ends, as shown in FIG. 11, the excitation electrodes 31 and 32 of the quartz diaphragm are drawn in the direction of the electrode pads 15 and 16 of the base 2, and the quartz crystal The electrode portion from which the diaphragm is drawn out and the electrode pads 15 and 16 are conductively bonded by, for example, a silicone-based conductive bonding material D. At this time, the third electrode pad 16 of the base and the excitation electrode (base facing side) 32 on the back surface side of the quartz crystal plate are electrically connected, and the second electrode pad 15 and the quartz plate of the quartz plate are connected. A surface-side excitation electrode (cap facing side) 31 is electrically connected. In addition, as described above, when the second and third electrode pads and the quartz diaphragm are joined by the conductive bonding material, the first and fourth electrode pads and the quartz diaphragm have a certain interval. It functions as a pillow material without being electrically and mechanically joined.

  The cap 2 that hermetically seals the base has, for example, a reverse concave shape that opens downward, and is made of an alumina ceramic material or a ceramic glass material. Although not shown, for example, a lead-based, bismuth-based, or tin phosphate-based low-melting glass material is formed on the bonding surface of the cap 2 as a sealing bonding material.

  In joining the base and the cap, the glass material formed on the cap is melted and hermetically sealed by heating at a predetermined temperature. In this hermetic sealing operation, in order to perform cap positioning and self-weight sealing, a pallet provided with storage portions in a matrix shape may be used and batch processing may be performed for a large number. Note that a weighted weight may be mounted on the base 1 to promote the bonding between the base and the cap. Moreover, in the said embodiment, although the glass joining material is formed in both joining area | regions of a base and a cap, you may form only in one of a base or a cap. This completes the surface-mount crystal unit.

  Next, a third embodiment according to the present invention will be described with reference to the drawings by taking a surface-mounted crystal resonator as an example. FIG. 12 is a base plan view showing the third embodiment, and FIG. 13 is a bottom view of FIG. Since the third embodiment is different from the second embodiment only in the lead-out configuration by the terminal electrode and the connection electrode, the same parts are given the same numbers and only the differences will be described.

  The base 1 has a shape having a concave piezoelectric vibration element housing portion 10 in cross section, and a circumferential glass layer 11a is formed on a bank portion 11 around the concave shape. Terminal electrodes 12, 13, 18, and 19 are formed at the four corners of the bottom surface of the base. On the upper and lower parts of the outer periphery of the base, castellations C1 and C2 are formed at the center of both ends in the long side direction, and castellations C3, C4, C5 and C6 are formed at the four corners. Of these, connecting electrodes 122 and 132 are formed below the castellations C3 and C5, and are electrically connected to the terminal electrodes 12 and 13 connected to the outside.

  As shown in FIGS. 12 and 13, four electrode pads 14, 15, 16, and 17 are formed at both ends in the short side direction and both ends in the long side direction on the bottom surface inside the base. The pads are electrically extended to the terminal electrodes 12 and 13 formed on the bottom surface of the base 1 via the connection electrodes 122 and 132 and the castellations C3 and C5. Then, the first electrode pad 14 and the second electrode pad 15 opposed in the short side direction are electrically extended independently to the terminal electrode 13 or the terminal electrode 12 on the bottom surface of the base so that they can be applied with different potentials. The first electrode pad 14 and the third electrode pad 16 opposed in the long side direction are connected in common by the connection electrode 140 so that they can be applied at the same potential, and are extended to the terminal electrode 13 on the bottom surface of the base. Has been. The second electrode pad 15 is connected to a dummy connection electrode 150 having substantially the same area and shape as the connection electrode 140 connected to the first electrode pad. The fourth electrode pad 17 facing the third electrode pad in the short side direction is a first terminal group connected to the first and third electrode pads, and a second terminal connected to the second electrode pad. The terminal group is not connected to any of the terminal groups and has no potential not extending to the terminal electrode. These terminal electrodes, connection electrodes, electrode pads, connection electrodes, dummy connection electrodes are formed by firing integrally with the base after printing a metallized material such as dungsten, molybdenum, etc. Nickel plating is formed on the metallized upper part, and gold plating is formed on the upper part.

  Bumps 141, 151, 161, 171 made of the same material as the electrode pads are formed on the electrode pads 14, 15, 16, 17. Among these, the bumps 141, 151, 161 formed on the electrode pad extending to the terminal electrode are in contact with the outer peripheral end portion of the crystal diaphragm (not shown) and the excitation electrode (base facing side) on the back surface side. It is formed at a position where it does not directly contact. In the case of this embodiment, even if the bumps 141, 151, 161 are formed in a substantially L shape so that the excitation electrode of the crystal diaphragm is enlarged on the other end side in the long side direction, the bumps are rectangular. The crystal diaphragm can be mounted in a shape corresponding to the outer peripheral end of the rectangular crystal diaphragm without reaching the shape of the excitation electrode (on the side facing the base). The bump 171 formed on the electrode pad 17 not extending to the terminal electrode has a slightly small rectangular shape corresponding to the shape of the electrode pad. When these bumps are formed, the electrode pad metallization is printed and formed, and after the electrode pad metallization is dried, the electrode pad and the bump are formed by printing according to the shape of the bump. They are formed simultaneously by firing integrally in a laminated state, and the nickel plating as described above is formed also on these metallized upper parts, and gold plating is formed on the upper parts.

  In the above embodiment, a substantially L-shaped, substantially U-shaped, rectangular, or single-character bump made of the same material as the electrode pad is used as an example, but as shown in FIG. A bump B1 may be formed, or a bump D1 made of another material such as a conductive adhesive may be formed on the electrode pad. Further, as shown in FIG. 14B, there is no particular problem even if the electrode pad omits the bump according to the design of the piezoelectric vibration device.

  Next, a fourth embodiment of the present invention will be described with reference to the drawings by taking a surface-mounted crystal resonator as an example. FIG. 15 is a base perspective view showing the fourth embodiment, and FIG. 16 is a plan view of FIG. The same parts as those in the above-described embodiment are given the same numbers, and only different points will be described.

  The base 1 is made of, for example, an alumina ceramic material, and has a rectangular flat base base, a frame having a large central portion with four corners projecting and an outer size approximately equal to the base base, and a central portion. Is formed with a frame body having an outer size substantially equal to that of the base substrate, and these layers are laminated and integrally fired. After the firing molding, the glass layer 11a is formed on the upper surface of the frame by a technique such as baking. That is, the base 1 has a shape including the concave piezoelectric vibration element housing portion 10 in the cross section and the support bases 142, 152, 162, and 172 at four corners, and on the bank portion 11 around the concave shape. A circumferential glass layer 11a is formed. On the upper and lower parts of the outer periphery of the base, castellations C1 and C2 are formed at the center of both ends in the long side direction, and castellations C3, C4, C5 and C6 are formed at the four corners. Of these, connection electrodes 121 and 131 are formed below the castellations C1 and C2, and are electrically connected to terminal electrodes 12 and 13 (not shown) connected to the outside.

  As shown in FIGS. 15 and 16, three electrode pads 14, 15, 16 are provided at both ends in the short side direction and at both ends in the long side direction on the support bases 142, 152, 162 inside the base, respectively. These electrode pads are electrically connected to the terminal electrodes 12 and 13 (not shown) formed on the bottom surface of the base 1 through the vias V, the connecting electrodes 121 and 131, and the castellations C1 and C2. It is extended to. Then, the first electrode pad 14 and the second electrode pad 15 opposed in the short side direction are electrically extended independently to the terminal electrode 13 or the terminal electrode 12 on the bottom surface of the base so that they can be applied with different potentials. The first electrode pad 14 and the third electrode pad 16 opposed in the long side direction are connected in common by the connection electrode 140 so that they can be applied at the same potential, and are extended to the terminal electrode 13 on the bottom surface of the base. Has been. The second electrode pad 15 is connected to a dummy connection electrode 150 having substantially the same area and shape as the connection electrode 140 connected to the first electrode pad. These terminal electrodes, connection electrodes, electrode pads, connection electrodes, dummy connection electrodes are formed by firing integrally with the base after printing a metallized material such as dungsten, molybdenum, etc. Nickel plating is formed on the metallized upper part, and gold plating is formed on the upper part.

  Among these electrode pads, the electrode pad 16 formed on the support base 162 that is not held when a quartz diaphragm (not shown) is cantilevered by the electrode pads 14 and 15 is located on the base center side of the support base 162. The ridgelines 1621 and 1622 are separated from each other. That is, an electrodeless region is formed in the vicinity of the ridgeline of the support base, and the excitation electrode on the base-facing side of the crystal diaphragm and the electrode pad 16 can be in a position where the electrode pad 16 is not in direct contact (a position that does not overlap). . For this reason, even if an external impact is applied to the surface-mounted crystal resonator and the crystal diaphragm is bent, no oscillation or the like is caused. Furthermore, even if the size of the quartz diaphragm is limited due to the downsizing of the base (package), when the quartz diaphragm is mounted on the base, the adverse effect of misalignment in the long side of the base is further eliminated, and the base length Since the excitation electrode of the crystal diaphragm can be further enlarged and formed in the side direction, the electrical characteristics of the crystal resonator can be further improved.

  A rectangular crystal diaphragm (not shown) is mounted on the electrode pads 14, 15, 16. When the quartz diaphragm is held in a cantilever manner, the excitation electrode of the quartz diaphragm is drawn out in the direction of the electrode pads 14 and 15 of the base 2, and the drawn electrode portion of the quartz diaphragm and the electrode pad 14 are drawn out. 15 are conductively bonded by, for example, a silicone-based conductive bonding material. At this time, the first electrode pad 14 of the base is electrically connected to the excitation electrode (base facing side) on the back side of the crystal diaphragm, and the second electrode pad 15 of the base and the crystal diaphragm are connected. Are electrically connected to the excitation electrode (cap facing side) on the surface side. In addition, as described above, when the first and second electrode pads and the crystal diaphragm are joined by the conductive bonding material, the third electrode pad 16, the support base 172, and the crystal diaphragm have a certain interval. It functions as a pillow material without being electrically and mechanically joined.

  Further, when both the quartz diaphragms are held, the excitation electrodes of the quartz diaphragm are drawn in the direction of the electrode pads 15 and 16 of the base 2, and the drawn electrode portion of the quartz diaphragm and the electrodes The pads 15 and 16 are conductively bonded by, for example, a silicone-based conductive bonding material. At this time, the third electrode pad 16 of the base is electrically connected to the excitation electrode (base facing side) on the back side of the crystal diaphragm, and the second electrode pad 15 and the surface of the crystal diaphragm are connected. The side excitation electrode (cap facing side) 31 is electrically connected. In addition, as described above, when the second and third electrode pads and the crystal diaphragm are joined by the conductive bonding material, the first electrode pad, the support base 172, and the crystal diaphragm have a certain interval. It functions as a pillow material without being electrically and mechanically joined in the state.

  A cap (not shown) is placed on the base, and the glass material formed on the cap is melted and hermetically sealed by heating at a predetermined temperature. This completes the surface-mount crystal unit.

  In the above embodiment, only the electrode pad 16 formed on the support base 162 that is not held when the crystal diaphragm is cantilevered by the electrode pads 14 and 15, the ridgeline 1621 on the base center side of the support base 162, The electrode pads 14 and 15 formed on the support bases 142 and 152 on which the crystal diaphragm is cantilevered are also formed as shown in FIG. You may form in the state which left | separated from the ridgeline 1421,1422,1521,1522 of the base center side of the support stand 142,152. With this configuration, in addition to the above-described effects, the electrode pad for joining the crystal diaphragm is formed with an electrodeless region separated from the ridge line of the support base. Is applied to improve the bonding strength. Further, as shown in FIG. 17B, the fourth electrode pad 17 is formed not only on the support bases 142, 152, and 162 but also on the support base 172, and the ridge line 1421 on the base center side of each of the support bases is formed. You may form in the state away from 1521,1621,1721. At this time, the fourth electrode pad 17 has no via formed therein, and the first terminal group connected to the first and third electrode pads, and the second electrode pad connected to the second electrode pad. It is configured so as not to be connected to any of the terminal groups and to have no potential that does not extend to the terminal electrode. With this configuration, in addition to the above-described effects, the fourth electrode pad 17 is also formed on the support base 172. Therefore, the height of the four support bases is the same, and the inclination when the crystal diaphragm is mounted. It is possible to adopt a configuration in which the occurrence of the Further, as shown in FIG. 17C, the support bases 162 and 172 are configured as one support base 182, and the third electrode pad 18 of the support base 182 is formed, and each of the support bases is formed. You may form in the state away from the ridgeline 1821 of the base center side. With this configuration, in addition to the above-described effects, the longer support base 182 along the short side direction can be used to make it difficult to cause tilting when the crystal diaphragm is mounted. In addition, although the shape which separates an electrode pad from the ridgeline of a support stand, ie, the shape of a non-electrode area | region, has become substantially L shape and single character shape, it is only an example and is not limited to these shapes.

  In the said embodiment, although the glass material is taken as an example as a sealing joining material, resin etc. may be sufficient. In addition, laser sealing using a metal cap for the ceramic base and a brazing material such as silver brazing material for the sealing bonding material, electron beam sealing, seam sealing, sealing by atmospheric heat treatment, etc. can also be applied. . Furthermore, in the above-described embodiment, a surface-mount type crystal resonator is taken as an example, but the present invention can also be applied to other surface-mount type piezoelectric vibration devices used for electronic devices such as a crystal filter and a crystal oscillator.

  The present invention can be implemented in various other forms without departing from the spirit or containment characteristics thereof, and should not be interpreted in a limited manner. The scope of the present invention is indicated by the claims, and is not limited 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.

FIG. 3 is an exploded perspective view of the surface-mount type crystal resonator showing the first embodiment. The base top view of FIG. The bottom view of FIG. FIG. 3 is a plan view of a state in which the crystal diaphragm of FIG. 2 is cantilevered. FIG. 3 is a plan view of a state in which the quartz diaphragm of FIG. 2 is held at both ends. The base top view which shows the modification of 1st Embodiment. The disassembled perspective view of the surface mount-type crystal resonator which shows 2nd Embodiment. The base top view of FIG. The bottom view of FIG. FIG. 8 is a plan view of a state in which the crystal diaphragm of FIG. 7 is cantilevered. FIG. 8 is a plan view of a state in which the quartz diaphragm of FIG. 7 is held at both ends. The base top view which shows 3rd Embodiment. The bottom view of FIG. The base top view which shows the modification of 1st, 2nd embodiment. The base perspective view which shows 4th Embodiment. The top view of FIG. The base top view which shows the modification of 4th Embodiment.

Explanation of symbols

1 Base 2 Cap 3 Crystal Diaphragm (Piezoelectric Vibrating Element)

Claims (5)

A piezoelectric vibration device having a rectangular base in plan view that holds a piezoelectric vibration element having excitation electrodes formed on the front and back surfaces, and a cap that hermetically seals the piezoelectric vibration element,
Three electrode pads are formed on the bottom inside the base,
Of the three electrode pads, the first electrode pad and the second electrode pad facing each other in a specific side direction extend to the terminal electrode of the base in an electrically independent state, and the specific side direction The first electrode pad and the third electrode pad facing each other in a direction orthogonal to the base electrode are extended to the base terminal electrode in a state of being commonly connected by the connection electrode,
The first electrode pad or the third electrode pad and the excitation electrode on the base facing side of the piezoelectric vibration element are electrically connected,
The piezoelectric vibration device, wherein the second electrode pad and an excitation electrode on the cap facing side of the piezoelectric vibration element are electrically connected. A piezoelectric vibration device having a rectangular base in plan view that holds a piezoelectric vibration element having excitation electrodes formed on the front and back surfaces, and a cap that hermetically seals the piezoelectric vibration element,
Four electrode pads are formed on the bottom inside the base,
Of the four electrode pads, the first electrode pad and the second electrode pad facing each other in a specific side direction extend to the terminal electrode of the base in an electrically independent state, and the specific side direction The first electrode pad and the third electrode pad, which face each other in the orthogonal direction, extend to the base terminal electrode in a state where they are commonly connected by the connection electrode, and face the third electrode pad in a specific side direction. Only the fourth electrode pad is configured so as not to extend to the terminal electrode of the base,
The first electrode pad or the third electrode pad and the excitation electrode on the base facing side of the piezoelectric vibration element are electrically connected,
The piezoelectric vibration device, wherein the second electrode pad and an excitation electrode on the cap facing side of the piezoelectric vibration element are electrically connected. The base is made of a ceramic material, the electrode pad is formed by metallization, and a bump made of the same material as the electrode pad is provided on the electrode pad extending to the terminal electrode, and the bump The piezoelectric vibration device according to claim 1, wherein the piezoelectric vibration device is formed at a position that does not overlap with the excitation electrode on the opposite side of the base of the piezoelectric vibration element. The base is made of a ceramic material, and has a support base for holding the piezoelectric vibration element on the upper surface. The electrode pad is formed by metallization on the support base, and at least the piezoelectric vibration element is not supported. The piezoelectric vibration device according to claim 1, wherein the electrode pad formed on the base is formed in a state of being separated from the ridge line on the base center side of the support base. The connection electrode connected to the first electrode pad and a dummy connection electrode having substantially the same area are connected to the second electrode pad. The piezoelectric vibration device as described.

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