JP4328226B2 - Piezoelectric oscillator - Google Patents

Description

  The present invention relates to a piezoelectric oscillator used as a timing device for communication equipment, electronic equipment, and the like.

  Conventionally, a piezoelectric oscillator such as a temperature-compensated crystal oscillator has been used as a timing device for a portable communication device or the like.

  For example, as shown in FIG. 4, such a conventional temperature-compensated crystal oscillator has a container body 23 in which a crystal resonator element is housed, a recess 25 in the center area of the upper surface, and a plurality of external terminals on the lower surface. The IC element 26 for controlling the oscillation output based on the vibration of the crystal resonator element is accommodated in the region surrounded by the lower surface of the container body 21 and the inner surface of the recess 25. The thing of the made structure is known (for example, refer patent document 1).

The container body 23 and the mounting base 21 are usually made of a ceramic material such as alumina ceramics, and a predetermined wiring pattern is formed inside and on the surface, and a conventionally known green sheet laminating method or the like is employed. It is produced by. A plurality of bonding electrodes 24 are provided at corresponding positions on the lower surface of the container body 23 and the upper surface of the mounting substrate 21, and the bonding electrodes 24 are made of a conductive bonding material. The container body 23 was fixed to the upper surface of the mounting base 21 by bonding through the two.
JP-A-10-98151

  However, in the above-described conventional piezoelectric oscillator, since the inner wall of the recess 25 provided in the mounting base 21 is arranged so as to surround the IC element 26, the area of the mounting base 21 is vertical. In any of the lateral directions, the size is larger than that of the IC element 26, which makes it difficult to reduce the size of the piezoelectric oscillator.

  The present invention has been devised in view of the above drawbacks, and an object thereof is to provide a piezoelectric oscillator suitable for reducing the overall structure.

According to one aspect of the present invention, a piezoelectric oscillator includes a rectangular container body that accommodates a piezoelectric vibration element therein and an IC element that outputs an oscillation signal corresponding to the oscillation frequency of the piezoelectric vibration element. It is fixed on a rectangular mounting substrate which is formed through a plurality of spacer members made of metal posts. The plurality of spacer members are provided at four corners of the mounting substrate. The IC element is covered with a resin material, and the resin material covers each side surface of the plurality of spacer members over the entire circumference.

Further, according to another aspect of the present invention, the mounting substrate is made of a glass cloth base epoxy resin, and the bonding electrode formed on the lower surface of the container body includes the conductive bonding material interposed therebetween. It is electrically connected to the wiring conductor formed on the substrate.

According to another aspect of the present invention, the resin material is a transparent material.

According to the piezoelectric oscillator of the present invention, a container body containing a piezoelectric vibration element is formed on a mounting base on which an IC element is mounted, and a plurality of metal posts including metal posts disposed at four corners of the mounting base . Since it is fixed via the spacer member, the entire area of the upper surface of the mounting substrate where no spacer member exists can be used for mounting IC elements and other electronic component elements. Can be miniaturized.

  Furthermore, according to the piezoelectric oscillator of the present invention, since the side surface of the spacer member is covered with the extending portion of the resin material over the entire circumference, the piezoelectric oscillator is soldered on an external wiring board such as a motherboard. When mounting, the piezoelectric oscillator that is easy to handle is designed to prevent the inconvenience that the solder that joins the piezoelectric oscillator and the external wiring board adheres to the spacer member made of a metal post and causes a short circuit. Can be obtained.

  Moreover, in this case, the side surface of the spacer member is covered with the resin material, so that the oxidative corrosion of the metal post forming the spacer member is effectively prevented, and the reliability of the piezoelectric oscillator can be maintained high. There is also an advantage that the attachment strength of the spacer member to the mounting substrate can be reinforced by the resin material.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is an exploded perspective view showing an embodiment in which the piezoelectric oscillator of the present invention is applied to a temperature-compensated crystal oscillator, and FIG. 2 is a cross-sectional view of the temperature-compensated crystal oscillator of FIG. The type quartz oscillator includes a rectangular container body 1 containing a crystal resonator element 5 serving as a piezoelectric resonator element, a rectangular container having a plurality of external terminals 10 on the lower surface and an IC element 7 on the upper surface. It has a structure in which it is placed and fixed via a spacer member 12 on a mounting substrate 6 having a shape.

  The container body 1 is made of, for example, a substrate 2 made of a ceramic material such as glass-ceramic or alumina ceramic, a seal ring 3 made of a metal such as 42 alloy, Kovar, or phosphor bronze, and a metal similar to the seal ring 3. The container body 1 is formed by attaching the seal ring 3 to the upper surface of the substrate 2 and placing and fixing the lid body 4 on the upper surface of the substrate 2, and is positioned inside the seal ring 3. A crystal resonator element 5 is mounted on the upper surface of the substrate 2 to be operated.

  The container body 1 is for hermetically sealing the quartz resonator element 5 in its interior, specifically, in a space surrounded by the upper surface of the substrate 2, the inner surface of the seal ring 3, and the lower surface of the lid body 4. A pair of mounting pads connected to the vibration electrode of the crystal resonator element 5 are provided on the upper surface of the substrate 2, and a plurality of bonding electrodes connected to a spacer member 12 described later are provided on the lower surface of the substrate 2. Each of these pads and the like are electrically connected to each other through wiring conductors on the surface of the substrate or via-hole conductors embedded in the substrate.

  When the substrate 2 of the container body 1 is made of a ceramic material such as glass-ceramic, for example, a wiring conductor is formed on the surface of a ceramic green sheet obtained by adding and mixing an appropriate organic solvent to the ceramic material powder. The conductor paste to be manufactured is applied by conventionally known screen printing or the like, and a plurality of the pastes are laminated and press-molded, followed by firing at a high temperature.

  The seal ring 3 and the lid 4 of the container body 1 are manufactured by forming a metal such as Kovar or 42 alloy into a predetermined shape by using a conventionally known metal processing method, and the obtained seal ring 3 is used as a substrate. 2 is brazed to a conductor layer previously deposited on the upper surface of the substrate 2, and then the quartz resonator element 5 is mounted and fixed on the upper surface of the substrate 2 using a conductive adhesive, and then the above-described lid body 4 is mounted in the related art. The container body 1 is assembled by joining to the upper surface of the seal ring 3 by known resistance welding or the like. In this way, when the seal ring 3 and the lid 4 are joined by resistance welding, a Ni plating layer, an Au plating layer, or the like is previously deposited on the surfaces of the seal ring 3 and the lid 4.

  On the other hand, the quartz crystal vibrating element 5 accommodated in the container body 1 is formed by attaching and forming a pair of vibrating electrodes on both main surfaces of a crystal piece cut along a predetermined crystal axis, and a variable voltage from the outside. Is applied to the quartz piece via a pair of vibrating electrodes, thickness shear vibration is caused at a predetermined frequency.

  The crystal resonator element 5 is mounted on the upper surface of the substrate 2 by electrically connecting a pair of vibration electrodes to a corresponding mounting pad on the upper surface of the substrate via a conductive adhesive, whereby the crystal resonator element 5 and the container are mounted. Electrical and mechanical connections with the body 1 are made simultaneously.

  Here, when the lid 4 of the container body 1 is connected to the external terminal 10 for the ground terminal disposed on the lower surface of the mounting substrate via the wiring conductor of the container body 1 and the mounting substrate 6, Since the lid 4 is grounded to provide a shielding function, the crystal resonator element 5 and the IC element 7 to be described later can be protected better than unnecessary electrical action from the outside. Therefore, the lid body 4 of the container body 1 is preferably connected to the external terminal 10 for the ground terminal via the wiring body of the container body 1 and the mounting base 6.

  The mounting base 6 on which the container body 1 is placed and fixed has a substantially rectangular shape, and spacer members 12 are individually attached and erected at the four corners of the upper surface of the mounting base. The IC element 7 is mounted in the central area of the upper surface of the mounting substrate surrounded by the spacer members 12.

  The mounting base 6 is for supporting the container body 1 with an IC element 7 and a spacer member 12 on the upper surface thereof, and a resin material such as glass cloth base epoxy resin, polycarbonate, epoxy resin, polyimide resin or the like. Or a ceramic material such as glass-ceramic or alumina ceramic.

  In addition, the spacer member 12 mounted and erected on the upper surface of the mounting base 6 is inclined so that a metal material such as copper is at least on the inner side surface and the upper region is located closer to the center of gravity of the spacer member than the lower region. It is formed by a metal post molded into a quadrangular prism shape, and the inclination angle is set so that the angle formed by the inclined surface and the center of gravity is 5 to 30 °. Further, the spacer member 12 is electrically and mechanically connected to the wiring conductor of the mounting substrate 6 at the lower end portion, and electrically and mechanically connected to the connection electrode on the lower surface of the container body via a conductive bonding material such as solder at the upper end portion. Mechanically connected.

  For example, nickel plating or gold plating is applied to the upper end surface of the spacer member 12 to a predetermined thickness in order to improve the bonding state of the conductive bonding material used for bonding to the container body 1. The

  Further, four external terminals 10 (a power supply voltage terminal, a ground terminal, an oscillation output terminal, and an oscillation control terminal) are provided on the lower surface of the mounting substrate 6, and these external terminals 10 are temperature compensated crystal oscillators. Is mounted on an external electric circuit such as a mother board (not shown), it is electrically connected to the circuit wiring of the external electric circuit by soldering or the like.

  Here, if the ground terminal and the oscillation output terminal of the four external terminals 10 are arranged close to each other, it is possible to effectively prevent noise from interfering with the oscillation signal output from the oscillation output terminal. Can do. Therefore, it is preferable to arrange the ground terminal and the oscillation output terminal close to each other.

  Furthermore, a plurality of electrode pads are deposited and formed on the upper surface of the mounting substrate 6 described above, and the above-described IC element 7 is mounted in the formation region of these electrode pads.

  As the IC element 7, for example, a rectangular flip chip IC having a plurality of connection pads corresponding to the electrode pads of the mounting base 6 on the lower surface is used, and the circuit formation surface ( The lower surface) has a temperature sensing element (thermistor) for detecting the ambient temperature state, a memory for storing temperature compensation data for compensating the temperature characteristics of the crystal vibration element 5, and the crystal vibration element 5 based on the temperature compensation data. A temperature compensation circuit that corrects vibration characteristics according to a temperature change, an oscillation circuit that is connected to the temperature compensation circuit and generates a predetermined oscillation output, and the like are provided. The oscillation output generated by the oscillation circuit is output to the outside. Then, for example, it is used as a reference signal such as a clock signal.

  In addition, the IC element 7 is disposed between adjacent spacer members at both ends thereof, and the two end surfaces disposed substantially in parallel are covered with a resin material 13 described later. More exposed.

  The exposed side surface of such an IC element 7 is slightly inside the outer periphery of the container body 1 or the mounting substrate 6, for example, 1 μm to 500 μm inside the outer periphery of the mounting substrate 6, and the outer periphery of the mounting substrate 6. In this case, since the width dimension of the mounting base 6 in the direction orthogonal to the exposed side surface of the IC element 7 is designed to be substantially equal to the length of one side of the IC element 7, The entire structure of the temperature compensated crystal oscillator can be made compact.

  The IC element 7 is mounted by individually bonding the connection pads provided on the lower surface thereof to the corresponding electrode pads on the upper surface of the mounting substrate through a conductive bonding material such as solder or gold bump. The electronic circuit in the IC element 7 is electrically connected to the crystal resonator element 5 and the external terminal 10 through the wiring conductor of the container body 1 and the wiring conductor of the mounting base 6. Is done.

  When the mounting substrate 6 is made of a glass cloth base epoxy resin, the glass cloth base formed by weaving glass yarn is impregnated with a liquid precursor of the epoxy resin, and the precursor is polymerized at a high temperature. By forming the base, the spacer member 12 made of a metal post and the wiring conductor are formed by processing a metal foil such as a copper foil adhered to the surface of the base into a predetermined pattern by a subtractive method. When the container body 1 is attached / fixed to the mounting substrate 6 via the spacer member 12, the upper surface of the spacer member 12 is bonded to the lower surface of the container body via a conductive bonding material such as solder. The container body 1 is mounted on the mounting substrate 6 by bringing the conductive bonding material into contact with the electrodes, and then electrically and mechanically connecting the conductive bonding material by applying heat.

  Further, the above-described IC element 7 is covered with a resin material 13 made of, for example, an epoxy resin, and the outer peripheral portion of the resin material 13 extends to the outer peripheral portion of the mounting base 6 and is adjacent to the spacer member. It fills the gap between them. At this time, the extending portion of the resin material 13 is attached to the inclined surface of the spacer member 12 described above.

  As described above, the characteristic feature of the piezoelectric oscillator according to the present embodiment is that at least the inner side surface of the spacer member 12 is inclined so that the upper region is located closer to the center of gravity of the spacer member than the lower region. With such a configuration, the angle formed by the spacer member 12 and the upper surface of the mounting substrate 6 becomes an obtuse angle. Therefore, when forming the resin material 13 that covers the IC element 7, the spacer member 12 and the IC element 7 are formed. The liquid resin before curing can easily flow in between, and the sealing performance of the IC element 7 can be improved.

  Further, since the spacer member 12 is attached to the four corners of the upper surface of the mounting base 6 and each of them has a trapezoidal cross section, the space between the spacer member 12 and the IC element 7 is efficiently widened. In addition, the liquid resin before curing can more easily flow between the spacer member 12 and the IC element 7, and the sealing performance of the IC element 7 can be further improved.

  The resin material 13 is mainly for protecting the IC element 7. However, if the side surface of the spacer member 12 is covered with the extending portion of the resin material 13 over the entire circumference, the temperature-compensated crystal is used. When the oscillator is mounted on an external wiring board such as a mother board by soldering or the like, the solder for joining the temperature compensated crystal oscillator and the external wiring board adheres to the spacer member 12 made of a metal post and causes a short circuit. Is effectively prevented, and a temperature-compensated crystal oscillator that is easy to handle can be obtained.

  In addition, in this case, since the side surface of the spacer member 12 is covered with the resin material 13, the oxidative corrosion of the metal post forming the spacer member 12 is effectively prevented, and the reliability of the temperature compensated crystal oscillator is maintained high. In addition, there is an advantage that the attachment strength of the spacer member 12 to the mounting base 6 can be reinforced by the resin material 13.

  In addition, it is preferable that 90% or more of the total area of the side surface of the spacer member 12 is covered with the resin material 13, but the entire side surface is necessarily covered with the resin material 13. Instead, for example, even when the side surface is exposed in the region of about 25% of the upper portion of the spacer member 12, if the other part is covered with the resin material 13, the mounting to the external wiring board is possible. Generation of a short circuit due to the adhesion of solder is effectively prevented, and there is almost no influence of oxidative corrosion due to contact with moisture contained in the atmosphere.

  Further, if the above-described resin material 13 is formed of a transparent material, even if the side surface of the IC element 7 exposed from the adjacent spacer members 12-12 is covered with the resin material 13, the mounting substrate 6 is not affected. Since the joint portion can be directly viewed, the joining state of the IC element 7 can be easily confirmed by visual inspection or the like when inspecting the product, and the inspection workability can be improved.

  A plurality of write control terminals 11 for writing temperature compensation data to the IC element 7 are interposed between the container body 1 and the mounting substrate 6 described above.

  Similarly to the spacer member 12 described above, the write control terminal 11 is formed by a metal post formed of a metal material such as copper in a columnar shape, and a part of the side surface is formed between the container side surface and the mounting substrate side surface. It is attached to the upper surface of the mounting substrate 6 so as to be exposed from between.

  These write control terminals 11 are juxtaposed along the edge of the mounting base 6 and are electrically connected to the IC element 7 via the wiring conductors of the mounting base 6. Therefore, after assembling the temperature compensated crystal oscillator, the probe needle of the temperature compensation data writing device is applied to these write control terminals 11 from the side, and the temperature compensation data corresponding to the temperature characteristics of the crystal resonator element 5 is written. As a result, the temperature compensation data is stored in the memory of the IC element 7.

  Thus, the write control terminal 11 for writing the temperature compensation data to the IC element 7 is formed by the metal post, and a part of the write control terminal 11 is provided between the side surface of the container body and the side surface of the mounting substrate. When the temperature compensated crystal oscillator is assembled, the temperature compensated crystal oscillator is manufactured simply by attaching the write control terminal 11 made of a metal post to a predetermined position on the upper surface of the mounting substrate. Therefore, the productivity of the temperature compensated crystal oscillator can be improved.

  The write control terminal 11 is preferably bonded at its upper end to a dummy bonding pad provided on the lower surface of the container body 1 via a bonding material. The bonding strength between the substrate 6 and the container body 1 can be improved, and the reliability of the temperature compensated crystal oscillator can be maintained at a higher level.

  Thus, the above-described temperature compensated crystal oscillator is mounted on an external wiring board such as a mother board by soldering or the like, and the oscillation output is corrected by the temperature compensation circuit of the IC element 7, and according to the resonance frequency of the crystal resonator element 5. By outputting a predetermined oscillation signal, it functions as a temperature compensated crystal oscillator.

  In addition, this invention is not limited to the above-mentioned embodiment, A various change, improvement, etc. are possible in the range which does not deviate from the summary of this invention.

  For example, in the above-described embodiment, a crystal oscillator using a crystal resonator element as a piezoelectric resonator element has been described as an example. The present invention can also be applied to the case where a piezoelectric oscillator is configured using a piezoelectric vibration element such as the above.

  In the above-described embodiment, a conductive bonding material is used to bond the container body 1 and the spacer member 12 on the mounting base 6. However, this conductive bonding material is a common material such as solder. For example, an anisotropic conductive adhesive or the like may be used as the conductive bonding material, and in this case, it is very easy to attach the container body 1 to the mounting substrate 6. Thus, there is also an advantage that the assembly process of the temperature compensated crystal oscillator is further simplified.

  Further, in the above-described embodiment, the example in which the four spacer members 12 are attached to the four corners of the upper surface of the mounting substrate has been described. However, the number of the spacer members 12 is not limited to four. The present invention is also applicable to the case where the container body 1 is fixed on the mounting substrate 6 using three or five or more spacer members 12.

  Furthermore, in the above-described embodiment, the lid 4 of the container body 1 is bonded to the substrate 2 via the seal ring 3. Instead, a metallized pattern for bonding is formed on the upper surface of the substrate 2. In addition, the lid 4 may be directly welded to the metallized pattern.

  Furthermore, in the above-described embodiment, the seal ring 3 is directly attached to the upper surface of the substrate of the container body 1, but instead of this, the upper surface of the substrate 2 is made of the same ceramic material as the substrate 2. The frame body may be attached integrally, and the seal ring 3 may be attached to the upper surface of the frame body.

  Further, in the above-described embodiment, for example, as shown in FIG. 3, an electronic component element other than an IC element, such as a chip capacitor for noise removal, is provided on the upper surface of the mounting substrate 6 located between the adjacent spacer members 12-12. 14 or the like may be arranged, and in this case, a vacant area on the upper surface of the mounting substrate is used more effectively, and thus the piezoelectric oscillator can be further downsized.

It is a disassembled perspective view which shows one Embodiment which applied the piezoelectric oscillator of this invention to the temperature compensation type | mold crystal oscillator. It is sectional drawing of the temperature compensation type | mold crystal oscillator of FIG. It is a perspective view of the mounting substrate used for the piezoelectric oscillator according to another embodiment of the present invention. It is a disassembled perspective view of the conventional temperature compensation type | mold crystal oscillator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Container body 2 ... Board | substrate 3 ... Seal ring 4 ... Lid body 5 ... Quartz crystal vibration element (piezoelectric vibration element)
6 ... Mounting substrate 7 ... IC element 7a ... Connection pad 10 ... External terminal 11 ... Write control terminal 12 ... Spacer member 13 ... Resin material 14 ... Chip Capacitor

Claims (3)

A rectangular container housing a piezoelectric vibration element therein is placed on a metal post on a rectangular mounting substrate on which an IC element that outputs an oscillation signal corresponding to the oscillation frequency of the piezoelectric vibration element is mounted. A piezoelectric oscillator fixed through a plurality of spacer members comprising:
The plurality of spacer members are provided at four corners of the mounting substrate,
The IC element is covered with a resin material, and the resin material covers each side surface of the plurality of spacer members over the entire circumference . The mounting substrate is made of a glass cloth base epoxy resin,
The bonding electrode formed on the lower surface of the container body is electrically connected to a wiring conductor formed on the mounting base via a conductive bonding material. Piezoelectric oscillator. The piezoelectric oscillator according to claim 1, wherein the resin material is a transparent material.

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