JP5188753B2 - Piezoelectric oscillator - Google Patents

Description

  The present invention relates to a piezoelectric oscillator used in an electronic device or the like.

FIG. 4 is a cross-sectional view showing a conventional piezoelectric oscillator. FIG. 5 is a bottom view of a container constituting a conventional piezoelectric oscillator.
As shown in FIG. 4, a conventional piezoelectric oscillator 200 has a piezoelectric vibration element 202 mounted in a first recessed space 205 provided on one main surface of a substantially rectangular container body 201 made of a ceramic material or the like. A piezoelectric vibration element mounting pad 206 is formed on the main surface of the substrate portion of the first recess space 205, and the piezoelectric vibration element 202 is mounted on the piezoelectric vibration element mounting pad 206.
Further, a metal lid 204 is placed so as to cover the recessed space 205 of the container body 201 and is fixed to the top of the side wall of the container body 201, whereby the inside of the first recessed space 205 is hermetically sealed. .
An integrated circuit element 203 is mounted in a second recessed space 207 formed on the other main surface of the container body 201. A structure in which an integrated circuit element mounting pad 208 is formed on the main surface of the substrate portion of the second recess space 207 and the integrated circuit element 203 is bonded to the piezoelectric vibration element 202 by a conductive bonding material 209 is known. (For example, refer to Patent Document 1).

As shown in FIG. 5, external connection electrode terminals 210 are provided at the four corners of the top surface of the frame portion surrounding the second recessed space 207 of the container body 201, and a predetermined integrated circuit element is provided. 208 and the wiring pattern 211.
The integrated circuit element 203 is mounted on the container body 201 by conductively fixing the integrated circuit element mounting pad 208 and the integrated circuit element 203 via a conductive bonding material 209 such as a conductive adhesive or solder. .
As a method of bonding the integrated circuit element 203 to the container body 201, a conductive bonding material 209 is applied to the integrated circuit element mounting pad 208 formed on the bottom surface in the second recess space of the container body 201, and the integrated circuit The element 203 is mounted on the integrated circuit element mounting pad 208, and the integrated circuit element 203 is bonded to the integrated circuit element mounting pad 208 by heat treatment using reflow means.

JP 2007-104032 A

  However, in the conventional piezoelectric oscillator 200, the integrated circuit element mounting pad 208 is connected to the wiring pattern 211 connected to the piezoelectric vibration element and the external connection electrode terminal on the main surface of the substrate portion of the second recess space 207. ing. When the integrated circuit element 203 is bonded to the integrated circuit element mounting pad 208 provided on the substrate portion in the second recess space by using a conductive bonding material 209 such as a conductive adhesive or solder, the integrated circuit element 203 Is mounted on the integrated circuit element mounting pad 208 and heat-treated using a reflow means or the like, the molten conductive bonding material 209 flows out from the integrated circuit element mounting pad 208 onto the wiring pattern 211. As a result, the amount of the conductive bonding material 209 for connecting the integrated circuit element 203 on the integrated circuit element mounting pad 208 is reduced, and the continuity failure between the integrated circuit element mounting pad 208 and the integrated circuit element 203 is reduced. There is a possibility that the connection strength is lowered and the integrated circuit element is dropped.

  Further, in order to prevent the conductive bonding material 209 from flowing out of the integrated circuit element mounting pad 208, without forming the wiring pattern 211 connected to the integrated circuit element mounting pad 208 on the substrate portion in the second recessed space, Although it is considered to form and connect wiring inside the container body 201 using via holes or the like, there is a problem that the thickness of the piezoelectric oscillator 200 is increased because the number of stacked container bodies 201 is increased.

  Therefore, the present invention has been made in view of the above problems, and by preventing the amount of the conductive bonding material remaining on the integrated circuit element mounting pad from decreasing, it is possible to prevent a decrease in the connection strength of the integrated circuit element. An object of the present invention is to provide a piezoelectric oscillator that can be made thin and can be made thin.

The piezoelectric oscillator according to the present invention includes a container body provided with frame portions on both main surfaces of the substrate portion to provide a first recessed space and a second recessed space, and the substrate portion in the first recessed space. A piezoelectric vibration element mounted on the provided piezoelectric vibration element mounting pad; an integrated circuit element mounted on an integrated circuit element mounting pad provided on the substrate portion in the second recess space; and the first A lid that hermetically seals the recessed space, and a substrate electrode main surface in the second recessed space has a monitor electrode terminal electrically connected to the piezoelectric vibration element mounting pad, and the integrated circuit An element mounting pad and a wiring pattern extending from the monitor electrode terminal; and the substrate in the second recess space including the integrated circuit element mounting pad, the monitor electrode terminal and the wiring pattern. On the main surface of the part. Provided the insulating layer of the structure the main surface central area of the main surface central area of the element mounting pad and the monitor electrode terminal is exposed, the insulating layer is composed of quartz glass, the thickness of the insulating layer The integrated circuit element mounting pad and the monitor electrode terminal are thicker than the thickness.

According to the piezoelectric oscillator of the present invention, the insulating layer is provided on the integrated circuit element mounting pad by providing the insulating layer formed by leaving the integrated circuit element mounting pad in the second recess space. Therefore, when the integrated circuit element is mounted on the integrated circuit element mounting pad by the conductive bonding material, the conductive bonding material can be held on the integrated circuit element mounting pad by the insulating layer.
Therefore, since a predetermined amount of the conductive bonding material required for mounting the integrated circuit element can be ensured, it is possible to prevent the connection strength of the integrated circuit element from being lowered.
Further, since the insulating layer is formed so as to cover the wiring pattern, the conductive bonding material does not flow out on the wiring pattern, so that the external connection electrode terminal and the integrated circuit are formed on the bottom surface in the second recess space. Since a wiring pattern for connecting the element mounting pads can be formed, the piezoelectric oscillator can be made thinner than a piezoelectric oscillator in which connection wiring is provided inside the container body.

Further, since the insulating layer is constituted by a quartz glass, it can be formed by screen printing means.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. A case where quartz is used for the piezoelectric vibration element will be described.
For the sake of clarity, a part of the structure unnecessary for the description is not shown. Further, the illustrated dimensions are partially exaggerated.

  FIG. 1 is an exploded perspective view showing a piezoelectric oscillator according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line AA of FIG. FIG. 3 is a bottom view of the container body constituting the piezoelectric oscillator according to the embodiment of the present invention.

  The piezoelectric oscillator 100 shown in FIGS. 1 to 3 mainly includes a container body 10, a piezoelectric vibration element 20, a lid body 30, and an integrated circuit element 50. In the piezoelectric oscillator 100, a piezoelectric vibration element 20 is mounted in a first recessed space 11 formed on one main surface of the container body 10, and is formed on the other main surface of the container body 10. The integrated circuit element 50 is mounted in the second recessed space 12.

As shown in FIGS. 1 and 2, the piezoelectric vibration element 20 is formed by, for example, forming an excitation electrode 21 on a quartz base plate, and an alternating voltage from the outside passes through the excitation electrode 21 to form a quartz element. When applied to the plate, excitation occurs in a predetermined vibration mode and frequency.
The quartz base plate is a substantially flat plate shape that is cut from an artificial crystalline lens at a predetermined cut angle and is subjected to external processing, and has a planar shape of, for example, a quadrangle.
The excitation electrode 21 is deposited and formed on both the front and back main surfaces of the quartz base plate.
Such a piezoelectric vibration element 20 includes a conductive adhesive and an excitation electrode 21 attached to both main surfaces of the piezoelectric vibration element 20 and a piezoelectric vibration element mounting pad 13 provided on the inner bottom surface of the first recess space 11. It is mounted in the first recessed space 11 by being electrically and mechanically connected by 70 (see FIG. 2).

  Further, as shown in FIG. 1, the integrated circuit element 50 is provided with an oscillation circuit or the like for generating an oscillation output from the piezoelectric vibration element 20 on the circuit forming surface, and an output signal generated by this oscillation circuit is an external signal. The signal is output to the outside of the piezoelectric oscillator 100 through a predetermined terminal among the connection electrode terminals 14 and used as a reference signal such as a clock signal, for example. The integrated circuit element 50 is mounted on the integrated circuit element mounting pad 15 on the substrate portion 10a in the second recessed space of the container body 10 to be described later.

The container body 10 includes a substrate portion 10a and frame portions 10b and 10c provided on both main surfaces of the substrate portion 10a.
For example, it is formed by laminating a plurality of ceramic materials such as alumina ceramics and glass-ceramics.
As shown in FIGS. 1 and 2, the first concave space 11 is formed by one main surface of the substrate portion 10a and the frame portion 10b, and the second main surface of the substrate portion 10a and the frame portion 10c are the second. The recessed space 12 is formed.
An annular sealing conductor pattern 16 is formed on the entire circumference of the opening-side top surface of the frame portion 10b that surrounds the first recessed space 11 of the container body 10. A piezoelectric vibration element mounting pad 13 is provided on the substrate portion 10 a in the first recess space 11.
As shown in FIG. 3, a monitor electrode terminal 17 is provided at the center of the substrate portion 10 a in the second recessed space 12 of the container body 10.
An integrated circuit element mounting pad 15 for mechanically bonding the integrated circuit element 50 is provided around the monitor electrode terminal 17.
The external connection electrode terminals 14 are provided at the four corners of the opening-side top surface of the frame portion 10 c that surrounds the second recessed space 12.
The integrated circuit element mounting pad 15 and the external connection electrode terminal 14 include a wiring pattern 18 having a portion formed in the substrate portion 10 a in the second recessed space 12 of the container body 10 and the second recessed space 12. They are connected by via conductors (not shown) formed inside the surrounding frame portion 10c.
The monitor electrode terminal 17 is not mechanically connected to the integrated circuit element 50.

The sealing conductor pattern 16 may be provided so as to cover the inner side surface and the outer side surface of the frame portion 10b forming the first recessed space 11.
This sealing conductor pattern 16 is used when a lid 30 (to be described later) is joined to the container body 10 to improve the wettability of the sealing member 31 formed on the lid 30 and facilitate joining. Yes. And Thereby, the airtight reliability and productivity of the 1st recessed part space 11 can be improved.

  The piezoelectric vibration element mounting pad 13 connected to the excitation electrode 21 is formed on a wiring conductor (not shown), a via-hole conductor (not shown), etc. inside the container body 10 and the bottom surface in the second recess space 12. The wiring pattern 18 and the integrated circuit element mounting pad 15 are electrically connected to the integrated circuit element 50.

As shown in FIG. 3, the integrated circuit element mounting pad 15 is provided around the monitor electrode terminal 17 provided at the center of the substrate portion 10 a in the second recessed space 12 of the container body 10. .
Further, the integrated circuit element mounting pad 15 is electrically and mechanically connected to the connection pad formed on the integrated circuit element 50 via a conductive bonding material 60 (see FIG. 2) such as solder or conductive adhesive. Is done. Further, the integrated circuit element mounting pad 15 is provided with a wiring pattern 18 formed on the substrate portion 10 a in the second recessed space 12 of the container body 10 or a wiring conductor (not shown) formed inside the container body 10. ), Via-hole conductors (not shown), etc., the electronic circuit in the integrated circuit element 50 is electrically connected to the crystal resonator element 20 and the external connection electrode terminal 14.

As shown in FIG. 3, the monitor electrode terminal 17 is provided at the center of the substrate portion 10 a in the second recessed space 12 on the other main surface of the container body 10, and the integrated circuit element mounting pad 15. It is formed in a larger shape.
The monitor electrode terminal 17 is connected to the piezoelectric vibration element 20 via a piezoelectric vibration element mounting pad 13 provided on the substrate portion 10 a in the first recessed space 11 of the container body 10. And used to measure electrical characteristics such as a CI (crystal impedance) value and a resonance frequency value of the piezoelectric vibration element 20.

The insulating layer 19 is made of aluminum oxide or quartz glass. The insulating layer 19 is formed of an alumina coat made of aluminum oxide or the like, or a glass coat made of quartz glass or the like. The insulating layer 19 has a structure in which the central area of the main surface of the integrated circuit element mounting pad 15 and the central area of the main surface of the monitoring electrode terminal 17 are exposed, and the integrated circuit element mounting pad 15 and the monitoring electrode terminal 17 are exposed. And on the main surface of the substrate portion 10a in the second recess space including the wiring pattern 18. The insulating layer 19 is baked after being provided by screen printing means using a mask jig for masking the main surface central region of the integrated circuit element mounting pad 15 and the main surface central region of the monitor electrode terminal 17. Is formed.
The insulating layer 19 has a thickness of 10 to 50 μm. Since this is thicker than the thickness dimension of the integrated circuit element mounting pad 15 and the monitor electrode terminal 17, it is possible to prevent the conductive bonding material 60 from flowing out onto the wiring pattern 18.
As a result, a predetermined amount of the conductive bonding material 60 for connecting the integrated circuit element 50 can be secured, so that it is possible to prevent the connection strength of the integrated circuit element 50 from being lowered.
For example, the insulating layer 19 can be collectively formed by screen printing means in the second recessed space of each container body on the container body in which a plurality of container bodies 10 are arranged and assembled in a planar shape.

  Further, if the ground terminal and the oscillation output terminal are arranged close to each other among the four external connection electrode terminals 14, 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.

The lid body 30 is disposed and joined on the first recessed space 11 of the container body 10. The lid 30 is provided with a sealing member 31 at a location facing the first recessed space 11.
Further, such a sealing member 31 can relieve unevenness on the surface of the sealing conductor pattern 16 and prevent a decrease in hermeticity.

  Further, the lid 30 disposed on the container body 10 is manufactured by adopting a conventionally known metal processing method and shaping a metal such as 42 alloy into a predetermined shape. A nickel (Ni) layer is formed on the upper surface of the lid body 30, and further, gold tin (Au—Sn) which is a sealing member 31 at least at a location facing the sealing conductor pattern 11 on the upper surface of the nickel (Ni) layer. ) Layer is formed. The thickness of the gold tin (Au—Sn) layer is 10 μm to 40 μm. For example, the component ratio is 80% gold and 20% tin.

  The conductive adhesive 70 contains a conductive filler in a silicone resin. The conductive powder includes aluminum (Al), molybdenum (Mo), tungsten (W), and platinum (Pt). , Palladium (Pd), silver (Ag), titanium (Ti), nickel (Ni), nickel iron (NiFe), or a combination thereof is used.

  In the case where the container body 10 is made of alumina ceramics, the piezoelectric vibration element mounting pad 13 and external connection are provided on the surface of a ceramic green sheet obtained by adding and mixing an appropriate organic solvent to a predetermined ceramic material powder. Conductor paste that becomes electrode terminals 14, integrated circuit element mounting pads 15, sealing conductor patterns 16 and the like, and also becomes via conductors in through-holes that have been previously punched by punching the ceramic green sheet. A conductive paste is applied by well-known screen printing, and a plurality of the pastes are laminated and press-molded, and then fired at a high temperature.

  The sealing conductor pattern 16 includes a first recess space 11 in which a nickel (Ni) layer and a gold (Au) layer are sequentially formed on the surface of a base layer made of, for example, tungsten (W), molybdenum (Mo), or the like. Is formed to have a thickness of 10 μm to 25 μm.

In addition, this invention is not limited to the said 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, the case where quartz is used as the piezoelectric material constituting the piezoelectric vibration element 20 has been described. However, as other piezoelectric materials, lithium niobate, lithium tantalate, or piezoelectric ceramics is used as the piezoelectric material. The piezoelectric vibration element used may be used.

1 is an exploded perspective view showing a piezoelectric oscillator according to an embodiment of the present invention. It is AA sectional drawing of FIG. It is a bottom view of a container body constituting a piezoelectric oscillator according to an embodiment of the present invention. It is sectional drawing which shows the crystal oscillator which is an example of the conventional piezoelectric oscillator. It is a container bottom view which comprises the conventional piezoelectric oscillator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Container body 10a ... Board | substrate part 10b, 10c ... Frame part 11 ... 1st recessed part space 12 ... 2nd recessed part space 13 ... Piezoelectric vibration element mounting pad 14 ... -External connection electrode terminal 15 ... Integrated circuit element mounting pad 16 ... Sealing conductor pattern 17 ... Monitor electrode terminal 18 ... Wiring pattern 19 ... Insulating layer 20 ... Piezoelectric vibration element

DESCRIPTION OF SYMBOLS 21 ... Excitation electrode 30 ... Cover body 31 ... Sealing member 50 ... Integrated circuit element 60 ... Conductive bonding material 70 ... Conductive adhesive agent 100 ... Piezoelectric oscillator

Claims (1)

A container body provided with a frame portion on both main surfaces of the substrate portion and provided with a first recess space and a second recess space;
A piezoelectric vibration element mounted on a piezoelectric vibration element mounting pad provided on the substrate portion in the first recess space;
An integrated circuit element mounted on an integrated circuit element mounting pad provided on the substrate portion in the second recess space;
A lid for hermetically sealing the first recess space;
The main surface of the substrate in the second recess space is extended from the monitoring electrode terminal electrically connected to the piezoelectric vibration element mounting pad, the integrated circuit element mounting pad, and the monitoring electrode terminal. Wiring pattern is provided,
On the main surface of the substrate portion in the second recess space including the integrated circuit element mounting pad, the monitor electrode terminal and the wiring pattern, a central area of the main surface of the integrated circuit element mounting pad and the monitor An insulating layer having a structure in which the central region of the main surface of the electrode terminal is exposed,
The insulating layer is made of quartz glass;
The thickness of the insulating layer is thicker than the thickness of the integrated circuit element mounting pad and the monitor electrode terminal.

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