JP2017050773A - Surface mounting type crystal oscillation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface mounting type crystal oscillation device that prevents overlapping of spurious noises to an oscillation circuit output attributed to radiation noises.SOLUTION: The surface mounting type crystal device is configured by housing a crystal oscillator 12 and an IC chip 8 in a recess 2 of a container body (package) 1 formed of a ceramic material. A conductive pattern 18 is provided at both sides of a circuit terminal 10a connected to an output terminal 9a of the IC chip 8. The conductive pattern 18 is connected to a grounding terminal out of mounting terminals 21. Thereby, a radiation noise entering to a neighborhood of the circuit terminal is released to the ground.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a quartz crystal device, and more particularly to a surface mount type quartz crystal device in which an IC chip constituting an oscillation circuit together with the quartz crystal resonator is accommodated in a common ceramic container.

  As a surface-mount type crystal device in which a crystal resonator and an IC chip constituting an oscillation circuit together with the crystal resonator are accommodated in a common ceramic container, those having various functions are known. For example, a surface-mount type VCXO (voltage controlled oscillator) is configured by housing a crystal resonator and an IC chip in a container formed of a ceramic material and provided with a plurality of terminals (mounting terminals) on a mounting surface. The terminals of the crystal unit and the circuit terminals connected to the input / output terminals and the mounting terminals of the IC chip are connected by bonding wires.

  FIG. 3 is a schematic diagram for explaining a conventional example of a surface-mount type crystal device constructed by housing a crystal resonator and an IC chip in a common ceramic container. FIG. 3 (a) is a plan view showing the arrangement inside the container. The figure and the figure (b) are sectional drawings which followed the CC 'line of the figure (a). In FIG. 9A, the lid 7 for sealing the concave opening end surface 6 and the metal ring 20 for fixing the lid 7 shown in FIG.

  This surface-mounted crystal device (hereinafter also simply referred to as a crystal device) is configured by accommodating a crystal resonator 12 and an IC chip 8 in a recess 2 of a container body (so-called package) 1 formed of a ceramic material. . In this configuration example, the IC chip 8 is fixed to the bottom surface 3 forming the recess 2 of the container body 1 with an appropriate adhesive. The crystal resonator 12 is fixed to a terminal pad (not shown) provided on a step portion (crystal fixing step portion) 5 near the recess opening end face 6 by a conductive adhesive 15 (15a, 15b).

  The quartz resonator 12 has an upper excitation electrode 13 and a lower excitation electrode 14 on the front and back of a quartz blank (quartz thin piece) 17 (upper and lower surfaces facing to FIG. 3B). In FIG. 3A, in order to make the arrangement of the lower excitation electrode 14 easier to understand, the same surface as the upper excitation electrode 13 is hatched. The upper excitation electrode 13 and the lower excitation electrode 14 have a wiring portion extending to one end of the quartz thin piece 17, and a terminal pad (provided on the quartz fixing step portion 5 with the above-described conductive adhesive 15 (15 a, 15 b)). (Not shown).

  The electrode pads provided on the crystal fixed step portion 5 are connected to a wiring pattern formed on the wiring step portion 4 provided below the crystal fixed step portion 5. A plurality of circuit terminals 10 corresponding to the plurality of input / output terminals 9 of the IC chip 8 are formed in the wiring step portion 4. FIG. 3 shows a state in which the output terminal 9a of the input / output terminal 9 of the IC chip 8 is connected to the circuit terminal 10a that connects to the output electrode of the circuit terminals 10 by the bonding wire 11 (11a). Other input / output terminals 9 and circuit terminals 10 are also connected by the same bonding wires 11. The circuit terminal 10 formed on the wiring step portion 4 is connected to a ground terminal (GND) of the mounting terminals 21 through a connection conductor of a circuit pattern formed on the interior or inner wall of the ceramic container body 1 through a wiring pattern (not shown). ) Is connected. Reference numeral 16 denotes an internal grounding film that shields the internal structure, and the internal grounding film 16 is also connected to the grounding terminal through a wiring pattern (not shown).

  The concave portion 2 of the container body 1 in which the crystal resonator 12 and the IC chip 8 are installed as described above is sealed with a lid 7 suitable for a metal plate via a metal ring 20 provided on the opening end surface 6 thereof. Has been.

  In addition to the VCXO shown in FIG. 3, this type of electronic device includes a piezoelectric device in which a piezoelectric vibrator represented by quartz and an IC chip are housed in a common ceramic container and having the same configuration as described above. Many. For example, Patent Literature 1 and Patent Literature 2 can be cited as disclosures of related art related to this type of electronic device.

JP 2007-235544 A JP2012-129679A

  In a configuration in which an IC chip and a crystal resonator are accommodated in a container body formed of ceramics or the like, there is no ground electrode around the circuit terminal 10a connected to the output terminal 9a of the IC chip 8 by the bonding wire 11. When external noise (radiation noise) enters the circuit of the bonding wire 11a that connects the terminal 10a and the output terminal 9a of the IC chip 8, this noise enters the oscillation circuit and is amplified to superimpose spurious noise on the oscillator output.

  An object of the present invention is to provide a surface-mount type crystal oscillation device that prevents spurious noise to an oscillation circuit output caused by radiation noise.

The above object is achieved by providing a conductor pattern connected to the ground on both sides of a circuit terminal serving as an output terminal of at least a plurality of circuit terminals connected to the output terminal of the IC chip of the crystal oscillator.
The typical configurations of the present invention are listed as follows.
(1) A surface-mount type crystal oscillating device according to the present invention has a plurality of mounting terminals for surface mounting on one surface, and a recess opened on the surface opposite to the one surface. A container body, a crystal resonator and an IC chip housed in the recess of the container body, and a lid that seals the recess of the container body,
The crystal resonator includes a pair of excitation electrodes formed on both surfaces of at least an effective vibration region of a crystal blank,
The IC chip has one surface fixed to the bottom surface of the concave portion of the container body, and has a plurality of input / output terminals on the opposite surface of the one surface, and constitutes an oscillation circuit together with the pair of excitation electrodes of the crystal resonator. Integrated circuit elements,
A wiring pattern connected to the pair of excitation electrodes and the plurality of mounting terminals of the crystal resonator is built in the container body, and has a plurality of circuit terminals connected to the wiring pattern in a part of the recess,
Conductor patterns connected to ground are provided on both sides of the circuit terminals connected to at least the output terminals of the IC chip among the plurality of circuit terminals.
(2) The IC chip and the crystal resonator are arranged so as to overlap each other in the concave portion of the container body.
(3) The lid was a metal plate.
(4) A solid ground film is provided on the bottom surface or the bottom surface inside the recess of the container body.

  The present invention is not limited to the above-described configuration, and various modifications can be made without departing from the technical idea of the present invention.

  By providing a conductor pattern to be connected to the ground on both sides of the circuit terminal provided on the container body serving as at least the output terminal of the plurality of circuit terminals connected to the output terminal of the IC chip of the crystal oscillator, the output terminal of the IC chip Radiation noise that enters around the circuit terminal connected to the output terminal connected to the output terminal with a bonding wire can be released to the ground, preventing spurious noise from appearing in the output of the crystal oscillator, and stable oscillation and high reliability A surface-mount type crystal device can be provided.

It is a schematic diagram explaining the Example of the surface mount-type crystal oscillation device which concerns on this invention. It is a schematic diagram which expands and shows the principal part of FIG. 1 explaining the Example of the surface mount-type crystal oscillation device which concerns on this invention. It is a schematic diagram explaining the prior art example of the surface mount-type crystal device comprised by accommodating the crystal oscillator and IC chip in the container main body.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings of the examples. It should be noted that the scope of the present invention is not limited to these forms unless otherwise specified in the following description.

  FIG. 1 is a schematic view for explaining a first embodiment of a surface-mount type crystal oscillation device according to the present invention. FIG. 1 (a) is a plan view showing the arrangement inside a container, and FIG. It is sectional drawing along the BB 'line | wire of (). In FIG. 6A, the lid 7 for sealing the recessed opening end face 6 and the metal ring 20 for fixing the body shown in FIG.

  The surface-mount type crystal device according to the present invention is configured by accommodating a crystal resonator 12 and an IC chip 8 in a recess 2 of a container body (package) 1 formed of a ceramic material. In this embodiment, the IC chip 8 is fixed to the bottom surface 3 that forms the recess 2 of the container body 1 with an appropriate adhesive. The crystal resonator 12 is fixed to an electrode pad (not shown) provided on the crystal fixing step 5 near the recess opening end face 6 by a conductive adhesive 15 (15a, 15b).

  The crystal resonator 12 has an upper excitation electrode 13 and a lower excitation electrode 14 on the front and back of a crystal blank (crystal thin piece) 17 (upper and lower surfaces facing the FIG. 1B). In FIG. 1A, in order to make the arrangement of the lower excitation electrode 14 easier to understand, the same surface as that of the upper excitation electrode 13 is hatched. The upper excitation electrode 13 and the lower excitation electrode 14 have a wiring portion extending to one end of the quartz thin piece 17, and the electrode pad provided on the quartz fixing step portion 5 with the above-described conductive adhesive 15 (15 a, 15 b). It is connected.

  The electrode pads provided on the crystal fixing step portion 5 are connected to a wiring pattern formed on the wiring step portion 4 provided below the crystal fixing step portion 5 (on the bottom surface 3 side). The wiring step portion 4 may be the bottom surface 3 of the recess, or may be the crystal fixing step portion 5. A plurality of circuit terminals 10 corresponding to the plurality of input / output terminals 9 of the IC chip 8 are formed in the wiring step portion 4. The wiring pattern formed on the wiring step portion 4 is connected to the mounting terminal 21 through a connection conductor of a circuit pattern formed on the interior or inner wall of the ceramic container body.

  A plurality of input / output terminals 9 of the IC chip 8 are connected to the wiring pads 10 by bonding wires 11. In FIG. 1, reference numeral 9 (the output terminal 9 a in FIG. 5B) is attached to the output terminal of the plurality of input / output terminals of the IC chip 8. The output terminal 9a is connected to the corresponding circuit terminal 10a by a bonding wire 11a. Other output terminals are connected to corresponding circuit terminals by similar bonding wires.

  The concave portion 2 of the container body 1 in which the crystal resonator 12 and the IC chip 8 are installed as described above is sealed with a lid 7 suitable for a metal plate via a metal ring 20 provided on the opening end surface 6 thereof. Is done.

  In the present embodiment, the conductor pattern 18 is provided on both sides of the circuit terminal 10a connected to the crystal oscillator output among the plurality of circuit terminals 10 provided in the wiring step portion 4. The conductor pattern 18 is connected to the ground terminal of the mounting terminals 21. The conductor pattern 18 can be formed simultaneously with the patterning of the circuit terminals 10. Note that a similar conductor pattern can be provided for any of the other circuit terminals that are necessary. For example, in a crystal oscillator of a type requiring an inverted output, a conductor pattern is provided along the circuit terminal 10b serving as the inverted output terminal.

  FIG. 2 is a schematic diagram for explaining a main part of a portion in which the input / output terminals of the IC chip in FIG. 1 and a plurality of circuit terminals 10 in the wiring step portion 4 are connected by bonding wires. FIG. FIG. 4B is a cross-sectional view taken along the line AA of FIG.

  In FIG. 2A, input / output terminals 9 (9 a to 9 h) are arranged on the upper surface of the IC chip 8. A plurality of circuit terminals 10 (10a to 10h) are formed on the wiring step 4 of the container body 1. The input / output terminals 9 (9a to 9h) and the circuit terminals 10 (10a to 10h) are electrically connected by bonding wires 11 (11a to 11h). Conductor patterns 18 are formed on both sides of the output terminal 10 a of the circuit terminals 10. The conductor pattern 18 is connected to a ground terminal among the mounting terminals via an internal circuit pattern (not shown).

  Thus, by providing a conductor pattern to be connected to the ground on both sides of the circuit terminal provided on the container body serving as an output terminal of at least the plurality of circuit terminals connected to the output terminal of the IC chip of the crystal oscillator, the IC chip The radiation noise that enters around the circuit terminal connected to the output terminal connected to the output terminal with a bonding wire can be released to the ground, and spurious noise is prevented from appearing in the output of the crystal oscillator, and stable oscillation A highly reliable surface-mount crystal device can be provided.

  In addition, as shown in FIG.1 (b), a container main body can be comprised with a multilayer ceramic sheet, and the solid conductor film 16 can also be provided in the mounting side inside. If it is a single-layer ceramic sheet, a solid film of the same conductor may be formed on the bottom surface of the recess 2. By carrying out like this, the penetration | invasion of the radiation noise to the inside of the container main body 1 can further be suppressed.

  According to this embodiment, it is possible to provide a surface-mount type crystal oscillation device that prevents spurious noise from being mixed into the oscillation circuit output caused by radiation noise entering the output terminal.

  The present invention is not limited to the above-described example of the VCXO, but uses a piezoelectric vibrator such as a crystal vibrator, and is widely applied to electronic devices in which operating conditions such as oscillation frequency fluctuate due to external noise. Applicable. Further, the present invention is not limited to the crystal resonator using the crystal flakes shown in the above-described embodiments, but also applies to a so-called mesa resonator formed by etching a crystal plate. Needless to say, you can.

DESCRIPTION OF SYMBOLS 1 ... Container main body 2 ... Concave 3 ... Bottom surface 4 ... Wiring step part 5 ... Crystal fixed step part 6 ... Concave opening end surface 7 ... Cover body 8 ... IC chip DESCRIPTION OF SYMBOLS 9 ... Input / output terminal 10 ... Circuit terminal 11 ... Bonding wire 12 ... Crystal oscillator 13 ... Upper excitation electrode 14 ... Lower excitation electrode 15 (15a, 15b) ... Conductive adhesive 16 ... interior grounding film 17 ... crystal blank 18 ... conductor pattern 20 ... metal ring

Claims (4)

A container body having a plurality of mounting terminals for surface mounting on one surface and having a recess opened on the surface opposite to the one surface, and a crystal housed in the recess of the container body A vibrator and an IC chip, and a lid that seals the concave portion of the container body,
The crystal resonator includes a pair of excitation electrodes formed on both surfaces of at least an effective vibration region of a crystal blank,
The IC chip has one surface fixed to the bottom surface of the concave portion of the container body, and has a plurality of input / output terminals on the opposite surface of the one surface, and constitutes an oscillation circuit together with the pair of excitation electrodes of the crystal resonator. Integrated circuit elements,
A wiring pattern connected to the pair of excitation electrodes and the plurality of mounting terminals of the crystal resonator is built in the container body, and has a plurality of circuit terminals connected to the wiring pattern in a part of the recess,
A surface-mount type crystal oscillation device, wherein a conductor pattern connected to ground is provided on both sides of a circuit terminal connected to at least an output terminal of the IC chip among the plurality of circuit terminals. In claim 1,
A surface-mount type crystal oscillation device, wherein the IC chip and the crystal resonator are arranged so as to overlap each other in the concave portion of the container body. In claim 1 or 2,
A surface-mount type crystal oscillation device, wherein the lid is a metal plate. In any one of Claims 1 thru | or 3,
A surface-mount type crystal oscillation device, characterized in that a solid grounding conductor film is provided on the bottom surface or inside of the bottom surface of the recess of the container body.

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