JP2005217731A - Piezoelectric oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric oscillator suitable for miniaturization of the entire structure. <P>SOLUTION: In the piezoelectric oscillator, a rectangular container body 1 housing a piezoelectric vibrating element 5 in the inside is fixed on a rectangular packaging base 6 on which an IC element 7 for outputting an oscillation signal corresponding to the oscillation frequency of the element 5 is mounted on the top surface, via a plurality of spacer members 12 consisting of metallic posts disposed along the external periphery of the packaging base 6. A projecting 13 is formed on the center region of each of the spacer members 12, joining pads 16 to be disposed so as to face the top surface of the spacer members 12 are formed on the bottom surface of the container body 1, and the spacer members 12 are connected to the joining pad 16 via a conductive joining material 15 surrounding the projecting portion 13. <P>COPYRIGHT: (C)2005,JPO&NCIPI

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. 3, the conventional temperature-compensated crystal oscillator includes a container body 23 in which a crystal resonator element 24 is accommodated, a recess 25 in the central area of the upper surface, and a plurality of external terminals 22 on the lower surface. And an IC element that controls the oscillation output based on the vibration of the crystal resonator element 24 in a region surrounded by the lower surface of the container body 21 and the inner surface of the recess 25. The thing of the structure which accommodated 26 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 adopted. It is produced by. A plurality of bonding electrodes are provided at corresponding positions on the lower surface of the container body 23 and the upper surface of the mounting substrate 21, and these bonding electrodes are bonded to each other via a conductive bonding material. As a result, the container body 23 was fixed to the upper surface of the mounting base 21.
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-described drawbacks, and an object thereof is to provide a piezoelectric oscillator having a structure suitable for downsizing the entire structure.

  The piezoelectric oscillator according to the present invention has a container body containing a piezoelectric vibration element therein and a mounting base on which an IC element that outputs an oscillation signal corresponding to the oscillation frequency of the piezoelectric vibration element is mounted. The container body is fixed through a plurality of spacer members made of metal posts arranged along the outer periphery thereof, and a convex portion is formed in a central area on the upper surface of the spacer member. A bonding pad disposed opposite to the upper surface of the spacer member is formed on the lower surface of the spacer member, and the spacer member and the bonding pad are bonded via a conductive bonding material surrounding the convex portion. is there.

  In the piezoelectric oscillator of the present invention, a quartz crystal vibrating element is used as the piezoelectric vibrating element, and temperature compensation data for correcting the oscillation signal according to a temperature state is stored in the IC element. A write control terminal composed of a metal post for writing temperature compensation data to the IC element is exposed between the body and the mounting base between the side of the container body and the side of the mounting base. It is characterized by being.

  According to the piezoelectric oscillator of the present invention, the container body containing the piezoelectric vibration element is placed on the mounting substrate on which the IC element is mounted via the spacer member made of the metal post disposed along the outer periphery thereof. Therefore, the entire area of the upper surface of the mounting substrate where no spacer member is present can be used for mounting IC elements and other electronic component elements. For example, the spacer member is mounted on the mounting substrate. When it is provided only at the four corners, the length of the mounting substrate can be made substantially equal to the length of the IC element by designing the both ends of the IC element between adjacent spacer members. This makes it possible to reduce the overall structure of the piezoelectric oscillator.

  In addition, a convex portion is formed in the central area of the upper surface of the spacer member, and a bonding pad is formed on the lower surface of the container body so as to face the upper surface of the spacer member, and the spacer member and the bonding pad are Since the bonding is performed through the conductive bonding material that surrounds the convex portion, a fillet of the conductive bonding material is formed from the bonding pad on the bottom surface of the container body to the upper surface of the spacer member, and thereby the bonding strength of the spacer member to the container body is increased. The mechanical strength of the piezoelectric oscillator can be maintained high, and the joining state of the container body and the spacer member can be easily confirmed by observing the above-mentioned fillet by visual observation or the like. Become.

  According to the piezoelectric oscillator of the present invention, a crystal resonator element is used as the piezoelectric resonator element, temperature compensation data for correcting the oscillation signal according to a temperature state is stored in the IC element, and the container body A state in which a part of a write control terminal made of a metal post for writing temperature compensation data to the IC element is exposed between the side surface of the container body and the side surface of the mounting substrate between the mounting substrate and the mounting substrate. Therefore, when assembling the piezoelectric oscillator, the piezoelectric oscillator can be manufactured simply by attaching the write control terminal made of a metal post to a predetermined position on the upper surface of the mounting substrate. It becomes possible to use for productivity improvement.

  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 body 4 of the container body 1 are manufactured by forming a metal such as 42 alloy into a predetermined shape by using a conventionally known metal processing method, and the obtained seal ring 3 is attached to the substrate 2. After brazing the conductor layer previously deposited on the upper surface, and subsequently mounting and fixing the crystal resonator element 5 on the upper surface of the substrate 2 using a conductive adhesive, the above-described lid body 4 is conventionally known. The container body 1 is assembled by joining to the upper surface of the seal ring 3 by 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.

  Further, the spacer member 12 attached and erected on the upper surface of the mounting base 6 is formed by a metal post formed by forming a metal material such as copper into a square column shape, and a rectangular parallelepiped convex portion 13 is formed on the upper surface thereof. It has.

  The spacer member 12 is electrically and mechanically connected to the wiring conductor of the mounting base 6 at the lower end thereof. Further, at the upper end portion, a fillet made of a conductive bonding material 15 such as solder is formed from the bonding pad 16 on the bottom surface of the container body 1 to the upper surface of the spacer member 12 and is electrically and mechanically connected to the bonding pad 16 on the lower surface of the container body 1. Yes. Thereby, the bonding strength of the spacer member 12 to the container body 1 is increased, the mechanical strength of the temperature compensated crystal oscillator can be maintained high, and the bonding state of the container body 1 and the spacer member 12 is described above. It is possible to easily confirm the fillet by visual observation or the like, and there is an advantage that the workability of the inspection is good.

  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 15 used for bonding to the container body 1. Is done.

  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.

  Further, 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 14 to be 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 connected to the corresponding electrode pad on the upper surface of the mounting substrate individually via a conductive bonding material 15 such as solder or gold bump, thereby allowing the IC element 7 to be connected to the IC element 7. The electronic circuit in the IC element 7 is electrically attached to the crystal vibrating 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 by being attached to the mounting base 6. Connected.

  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. A spacer formed of a metal post having a convex portion on the upper surface by forming a base by forming a base and using a conventionally known photo-etching or the like to form a metal foil such as a copper foil adhered to the surface of the base. The member 12 and the wiring conductor are formed. Further, when the container body 1 is attached and fixed on the mounting base 6 via the spacer member 12, the upper surface of the spacer member 12 corresponds to the lower surface of the container body via the conductive bonding material 15 such as solder. The container body 1 is mounted on the mounting substrate 6 by contacting the bonding electrode and then electrically and mechanically connecting the conductive bonding material 15 by melting the conductive bonding material 15 by applying heat. .

  Further, the above-described IC element 7 is covered with a resin material 14 made of, for example, an epoxy resin, and the outer peripheral portion of the resin material 14 extends to the outer peripheral portion of the mounting substrate 6 and is adjacent to the spacer member. A part of the gap is filled on the surface of the spacer member 12 so as to cover the side surface of the spacer member 12.

  The resin material 14 is for protecting the IC element 7, and the outer peripheral portion of the resin material 14 extends to the outer peripheral portion of the mounting base 6 as described above, and then the extended portion. When the temperature-compensated crystal oscillator is mounted on an external wiring substrate such as a mother board by soldering or the like by covering the side surfaces of the spacer members 12 with a thickness of, for example, 20 μm to 250 μm, the temperature-compensated crystal oscillator It is possible to effectively prevent the disadvantage that the solder that joins the external wiring board adheres to the spacer member 12 made of a metal post and causes a short circuit, and a temperature-compensated crystal oscillator that is easy to handle can be obtained. become able to.

  In this case, the side surface of the spacer member 12 is covered with the resin material 14, so that 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 substrate 6 can be reinforced by the resin material 14.

  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 14. For example, the side surface is about 25% from the upper end of the spacer member 12. Even if it is exposed, if other parts are covered with the resin material 14, it is possible to effectively prevent the occurrence of a short circuit due to the adhesion of solder during mounting on the external wiring board. In addition, there is almost no influence of oxidative corrosion caused by contact with moisture contained in the atmosphere.

  Further, if the above-described resin material 14 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 14, 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, but instead of this, a piezoelectric vibrator other than a crystal resonator element, specifically, a surface acoustic wave element 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, the conductive bonding material 15 is used to bond the container body 1 and the spacer member 12 on the mounting base 6. However, the conductive bonding material 15 is generally used for solder or the like. For example, an anisotropic conductive adhesive or the like may be used as the conductive bonding material 15, and in this case, the operation of attaching the container body 1 to the mounting substrate 6 is performed. There is also an advantage that the assembly process of the temperature-compensated crystal oscillator is further simplified because it becomes extremely simple.

  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 can also be applied 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 embodiment described above, 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.

  Furthermore, in the above-described embodiment, electronic component elements other than IC elements, for example, chip capacitors for noise removal, etc. are arranged on the upper surface of the mounting substrate 6 located between the adjacent spacer members 12-12. In this case, the vacant area on the upper surface of the mounting substrate is used more effectively, so that 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 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 ... Projection 14 ... Resin Material 15 ... conductive bonding material 16 ... bonding pad

Claims (2)

A container body containing a piezoelectric vibration element is disposed on the mounting base on which an IC element that outputs an oscillation signal corresponding to the oscillation frequency of the piezoelectric vibration element is mounted along the outer periphery thereof. A piezoelectric oscillator fixed through a plurality of spacer members made of metal posts,
A convex portion is formed in the central region of the upper surface of the spacer member, and a bonding pad is formed on the lower surface of the container body so as to face the upper surface of the spacer member. Piezoelectric oscillator characterized by being bonded via a conductive bonding material surrounding the portion. A quartz crystal vibration element is used as the piezoelectric vibration element, and temperature compensation data for correcting the oscillation signal according to a temperature state is stored in the IC element, and the container body and the mounting substrate The write control terminal comprising a metal post for writing temperature compensation data to the IC element is partially exposed between the side surface of the container body and the side surface of the mounting substrate. The piezoelectric oscillator according to 1.

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