JP5995388B2 - Piezoelectric oscillator - Google Patents

Description

  The present invention relates to a piezoelectric oscillator substrate and a piezoelectric oscillator using the same.

  Piezoelectric oscillators are used, for example, as a reference frequency generation source in portable communication devices. The piezoelectric oscillator has a piezoelectric vibration element mounted on the first main surface of the substrate portion and an IC element mounted on the second main surface of the substrate portion. The IC element is electrically connected to a plurality of IC element connection pads provided on the second main surface of the substrate portion. As an example of the piezoelectric oscillator, there is one having a shield layer provided in a substrate portion and disposed between a piezoelectric vibration element and a plurality of IC element connection pads.

JP 2007-158918 A

  However, in the above-described conventional piezoelectric oscillator, the output pad electrically connected to the output terminal of the IC element among the plurality of IC element connection pads is shielded in order to reduce the amount of noise from the piezoelectric vibration element to the output pad. Although it is necessary to cover with a layer, in such a structure having a shield layer, the frequency of the piezoelectric vibration element may fluctuate due to the influence of the shield layer.

  According to the piezoelectric oscillator of one aspect of the present invention, a substrate portion, a piezoelectric vibration element mounting pad provided on the first main surface of the substrate portion, and a plurality of pads provided on the second main surface of the substrate portion. A piezoelectric oscillator substrate having an IC element connection pad and a shield layer provided in the substrate portion, a piezoelectric vibration element mounted on a piezoelectric vibration element mounting pad of the piezoelectric oscillator substrate, and a piezoelectric oscillator substrate And an IC element electrically connected to the plurality of IC element connection pads, and the shield layer includes an output pad electrically connected to the output terminal of the IC element among the plurality of IC element connection pads. A signal input to the IC element from the piezoelectric vibration element or from the IC element does not cover the input pad electrically connected to the piezoelectric vibration element mounting pad among the plurality of IC element connection pads. Output Characterized in that that signal does not cover the internal wiring being transmitted.

  The piezoelectric oscillator according to one aspect of the present invention includes the piezoelectric oscillator substrate having the above-described configuration, thereby reducing fluctuations in the output frequency of the piezoelectric vibration element while reducing fluctuations in the output signal from the IC element. The characteristics of the output signal can be improved.

It is a disassembled perspective view which shows the piezoelectric oscillator in the 1st Embodiment of this invention. (A) is a longitudinal sectional view taken along the line AA of the piezoelectric oscillator shown in FIG. 1, and (b) is a transparent bottom view of the piezoelectric oscillator shown in FIG. FIG. 2C is a plan perspective view showing a shield layer and the like provided in the substrate portion shown in FIG. It is a longitudinal cross-sectional view which shows the modification of the piezoelectric oscillator shown by FIG. (A) is a longitudinal cross-sectional view of the piezoelectric oscillator in the second embodiment of the present invention, (b) is a transparent bottom view of the piezoelectric oscillator shown in (a) in a state in which the concave resin material is removed, (C) is a plane perspective view showing a shield layer and the like provided in the substrate part shown in (a). FIG. 5 is a longitudinal sectional view showing a modification of the piezoelectric oscillator shown in FIG. 4.

  Several exemplary embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
As shown in FIG. 1 and FIGS. 2A to 2C, the piezoelectric oscillator 100 according to the first embodiment of the present invention includes a piezoelectric oscillator substrate 10 and a first of the piezoelectric oscillator substrate 10. The piezoelectric vibration element 22 mounted on the piezoelectric oscillator substrate 10 by the conductive adhesive 40 and the second main surface of the piezoelectric oscillator substrate 10 is provided inside the recess. The IC element 30 mounted on the piezoelectric oscillator substrate 10 by the fixing member 50 is included. Further, the concave portion of the first main surface of the piezoelectric oscillator substrate 10 is closed by the lid member 24, and the concave portion of the second main surface of the piezoelectric oscillator substrate 10 is filled with the resin material 60. .

  The piezoelectric oscillator substrate 10 includes a substrate portion 11, a first frame portion 12 a provided on the first main surface of the substrate portion 11, and a second frame portion 12 b provided on the second main surface of the substrate portion 11. And a plurality of piezoelectric vibration element mounting pads 13 provided in a region inside the first frame portion 12 a on the first main surface of the substrate portion 11.

  The substrate unit 11 is formed by stacking a plurality of ceramic materials such as alumina, for example, and a shield layer 15 and an internal wiring 18 are provided in the substrate unit 11.

  The first frame portion 12 a is made of a ceramic material such as alumina similarly to the substrate portion 11, is provided on the first main surface of the substrate portion 11, and forms a recess together with the substrate portion 11.

  The second frame portion 12 b is made of a ceramic material such as alumina similarly to the substrate portion 11, is provided on the second main surface of the substrate portion 11, and forms a recess together with the substrate portion 11.

  The piezoelectric vibration element mounting pad 13 is made of, for example, a conductive material having high conductive efficiency, and is electrically connected to the internal wiring 18 of the substrate unit 11. The piezoelectric vibration element mounting pad 13 is gold-plated on the surface.

  The shield layer 15 is made of the same material as the internal wiring 18 of the substrate unit 11. For example, the substrate unit 11 is electrically connected to the GND terminal 17. The shield layer 15 covers the output pad 16a that is electrically connected to the output terminal of the IC element among the plurality of IC element connection pads 16, and the piezoelectric vibration element is mounted among the plurality of IC element connection pads 16. The input pad 16c electrically connected to the pad 13 is not covered. In the example shown in FIGS. 1 and 2, the shield layer 15 is arranged so as to cover only the output pad 16 a among the plurality of IC element connection pads 16. Note that some of the plurality of IC element connection pads 16 are indicated by an alphabet after the reference numeral 16 such as 16a and 16c.

  The IC element connection pad 16 is made of, for example, a conductive material having high conductivity efficiency, and is electrically connected to the IC element 30 via a metal-based conductive bonding agent.

  The piezoelectric vibration element 22 includes, for example, a plate-shaped piezoelectric substrate 21 and excitation electrodes 23 a and 23 b provided on the upper and lower surfaces of the piezoelectric substrate 21.

  The lid member 24 is made of, for example, a metal material and has a rectangular plate shape.

  The IC element 30 is a one-chip IC that forms a transmission circuit that outputs a stable frequency by controlling the frequency obtained from the piezoelectric vibration element 22. The IC element 30 is formed with bumps 16b arranged in an array. For example, in the case of a gold bump, the IC element 30 is electrically connected to the IC element connection pad 16 via the conductive adhesive 40. For example, in the case of a solder bump, it is electrically connected to the IC element connection pad 16 via solder.

  The piezoelectric oscillator substrate 10 in the present embodiment includes a shield layer 15 provided on the substrate unit 11, and the shield layer 15 covers the output pad 16 a among the plurality of IC element connection pads 16, and the input pad. By not covering 16c, noises from the piezoelectric vibration element 22 to the output pad 16a are reduced, and the capacitance added between the shield layer 15 and the input pad 16c is reduced. Therefore, the piezoelectric oscillator substrate 10 according to the present embodiment is reduced in noise from entering the output pad 16a, and the vibration characteristics of the piezoelectric vibration element 22 are improved.

  The piezoelectric oscillator 100 according to the present embodiment is mounted on the above-described piezoelectric oscillator substrate 10, the piezoelectric vibration element 22 mounted on the piezoelectric vibration element mounting pad 13 of the piezoelectric oscillator substrate 10, and the piezoelectric oscillator substrate 10. By including the IC element 30 electrically connected to the IC element connection pad 16, the fluctuation of the output frequency of the piezoelectric vibration element 22 is reduced while the fluctuation of the output signal from the IC element 30 is reduced. The characteristics of the output signal of the piezoelectric oscillator 100 can be improved.

  Further, if the structure of the shield layer 15 of the substrate unit 11 in the present embodiment is used, a structure in which the piezoelectric vibrator 20 is bonded to the substrate unit 11 as shown in FIG. 3 may be used. Even with such a structure, the capacitance added between the shield layer 15 and the input pad 16c is reduced, and the amount of noise from the piezoelectric vibration element 22 to the output pad 16a can be reduced.

(Second Embodiment)
A piezoelectric oscillator 200 according to a second embodiment of the present invention will be described with reference to FIGS. In the piezoelectric oscillator 200 in the present embodiment, the configuration different from the piezoelectric oscillator 100 in the first embodiment is that the shield layer 215 does not cover the internal wiring 18 of the piezoelectric oscillator substrate 210, the IC element mounting pad 16, and the IC element. 30 is a connection method. About another structure, it is the same as that of the piezoelectric oscillator 100 in 1st Embodiment.

  The IC element connection pad 16 in the present embodiment is made of, for example, a conductive material having high conductivity efficiency, and is electrically connected to the IC element 30 through a wire.

  The piezoelectric oscillator substrate 210 in the present embodiment includes a shield layer 215 provided on the substrate portion 11, and the shield layer 215 does not cover the internal wiring 18 of the piezoelectric oscillator substrate 210. The capacitance added between the internal wiring 18 is reduced. Accordingly, since the capacitance between the shield layer 215 and the internal wiring 18 is reduced, the stray capacitance of the piezoelectric oscillator substrate 210 is reduced, so that the vibration characteristics of the piezoelectric vibration element 22 are improved. . The internal wiring 18 transmits, for example, a signal input from the piezoelectric vibration element 22 to the IC element 30 or a signal output from the IC element 30.

  In the piezoelectric oscillator substrate 210 of the present embodiment, the shield layer 215 covers all of the plurality of IC element connection pads 16 except the input pad 16c, so that noise enters the output pad 16a. Has been reduced. Therefore, in the piezoelectric oscillator substrate 210 of the present embodiment, noise with respect to the plurality of IC element connection pads 16 is reduced.

  In the example shown in FIGS. 4A to 4C, the shield layer 215 covers not only the output pad 16a but also the output wire 16b among the plurality of IC element connection pads 16. In such a case, since the shield layer 215 covers the output wire 16b that is relatively susceptible to the influence from the outside, the noise from the piezoelectric vibration element 22 to the output pad 16a is further reduced.

  The piezoelectric oscillator 200 in this embodiment is mounted on the above-described piezoelectric oscillator substrate 210, the piezoelectric vibration element 22 mounted on the piezoelectric vibration element mounting pad 13 of the piezoelectric oscillator substrate 210, and the piezoelectric oscillator substrate 210. By including the IC element 30 electrically connected to the plurality of IC element connection pads 16, the fluctuation of the output frequency of the piezoelectric vibration element 22 is reduced while the fluctuation of the output signal from the IC element 30 is reduced. be able to. Therefore, the characteristics of the output signal of the piezoelectric oscillator 200 can be improved.

  In addition, as long as the shield layer 215 of the substrate unit 11 in the present embodiment has a structure, a structure in which the piezoelectric vibrator 20 is bonded to the substrate unit 11 as shown in FIG. Even with such a structure, fluctuations in the output frequency of the piezoelectric vibration element 22 can be reduced while reducing fluctuations in the output signal from the IC element 30. Therefore, the characteristics of the output signal of the piezoelectric oscillator 200 can be improved.

(Modification)
Hereinafter, a description will be given of modifications of the shield layer 15 and the shield layer 215 in the first embodiment and the second embodiment of the present invention.

  Although the shield layer 15 and the shield layer 215 in the first embodiment of the present invention and the second embodiment of the present invention are electrically connected to the GND terminal 17 through the internal wiring 18 of the substrate part 11, respectively. Instead of being connected to the GND terminal 17, it may be connected to the interface terminal of the IC element 30 subjected to pull-down resistance processing. The interface terminal of the IC element 30 that has been subjected to pull-down resistance processing has a low level voltage when there is no signal input / output, and thus is equivalent to a state of being electrically connected to the GND terminal 17. That is, the interface terminal of the IC element 30 is used to write data to the IC element 30 when manufacturing the piezoelectric oscillator 100 and the piezoelectric oscillator 200. After manufacturing the piezoelectric oscillator 100 and the piezoelectric oscillator 200, the IC element 30 Since no data is written in the memory 30, a pull-down resistance process is usually performed. Therefore, the shield layer 15 and the shield layer 215 of the modified example in the first embodiment of the present invention and the second embodiment of the present invention require internal wiring from the shield layer 15 and the shield layer 215 to the GND terminal 17. In addition, the number of stacked layers of the piezoelectric oscillator substrate 10 and the piezoelectric oscillator substrate 210 can be reduced. Therefore, the piezoelectric oscillator 100 and the piezoelectric oscillator 200 in the first embodiment and the second embodiment of the present invention are improved in terms of frequency characteristics without reducing the oscillation sensitivity, and the piezoelectric oscillator 100 and the piezoelectric oscillator. A reduction in height of 200 can be realized.

100,200 Piezoelectric oscillator
10,210 Piezoelectric oscillator substrate
11 Board part
12a First frame
12b Second frame
13 Piezoelectric vibration element mounting pad
14 fixed land
15,215 Shield layer
16 IC element connection pad
16a output pad
16b Output wire or output bump
16c input pad
17 GND terminal
18 Internal wiring
20 Piezoelectric vibrator
21 Piezoelectric substrate
22 Piezoelectric vibration element
23a, 23b Excitation electrode
24 Lid member
30 IC elements
40 conductive adhesive
50 Fixing member
60 resin material

Claims (3)

A substrate portion, a piezoelectric vibration element mounting pad provided on the first main surface of the substrate portion, a plurality of IC element connection pads provided on the second main surface of the substrate portion, and provided in the substrate portion A piezoelectric oscillator substrate having a shield layer formed thereon;
A piezoelectric vibration element mounted on the piezoelectric vibration element mounting pad of the piezoelectric oscillator substrate;
An IC element mounted on the piezoelectric oscillator substrate and electrically connected to the plurality of IC element connection pads;
The shield layer covers an output pad electrically connected to an output terminal of the IC element among the plurality of IC element connection pads, and the piezoelectric vibration element mounting pad among the plurality of IC element connection pads. Does not cover the electrically connected input pads,

A piezoelectric oscillator characterized by not covering an internal wiring through which a signal input from the piezoelectric vibration element to the IC element or a signal output from the IC element is transmitted. The IC element is electrically connected to the plurality of IC element connection pads by a plurality of bonding wires;
2. The piezoelectric oscillator according to claim 1, wherein the shield layer covers an output wire connected to the output pad among the plurality of bonding wires.   2. The piezoelectric oscillator according to claim 1, wherein the shield layer is electrically connected to an interface terminal of the IC element subjected to pull-down resistance processing.

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