JP2009016949A - Piezoelectric oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric oscillator capable of preventing connection strength between an integrated circuit element and a terminal section from decreasing, by preventing a decrease in the number of conductive jointing materials that remain in an integrated circuit element mounting pad and an electrode terminal for connecting conductors. <P>SOLUTION: The piezoelectric oscillator comprises a vessel body having a recessed space on one main surface; a piezoelectric vibrating element mounted in the recessed space; the integrated circuit element and the terminal section mounted on the other main surface of the vessel body; and a lid body for airtightly sealing the recessed space. In the piezoelectric oscillator, electrode terminals for connecting the terminal section provided at four corners of the other main surface of the vessel body, and the integrated circuit element mount pad provided at a center are provided. The electrode terminal for connecting the terminal section and integrated circuit element mount pad are connected by a wiring pattern formed on the other main surface of the vessel body, and an insulating layer is formed on the wiring pattern. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

FIG. 6 is a cross-sectional view showing a conventional piezoelectric oscillator. As shown in FIG. 6, a conventional piezoelectric oscillator 200 has a concave space 205 formed on one main surface of a substantially rectangular parallelepiped container body 201 made of a ceramic material or the like, and a piezoelectric vibration element formed on the bottom surface of the concave space 205. The piezoelectric vibration element 202 is mounted on the mounting pad 206.
Furthermore, 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 recessed space 205 is hermetically sealed.
Further, a structure in which the conductor 204 and the integrated circuit element 203 are bonded to the other main surface of the container body 201 by a conductive bonding material 207 is known. The conductor 204 is used as an external connection electrode terminal (see, for example, Patent Document 1).

Note that a conductor connecting electrode terminal 208 is provided at the edge of the other main surface of the container body 201, and an integrated circuit element mounting pad 209 is provided at the center.
The conductor connecting electrode terminal 208 and the integrated circuit element mounting pad 209 are connected on the main surface by a wiring pattern.
The conductive body connecting electrode terminal 208 and the conductive body 204, and the integrated circuit element mounting pad 209 and the integrated circuit element 203 are conductively fixed to each other through a conductive bonding material 207 such as a conductive adhesive or solder. The integrated circuit element 203 and the conductor 204 were joined to 201.
As a method of joining the integrated circuit element 203 and the conductor 204 to the container body 201, the integrated circuit element mounting pad 209 and the conductor connecting electrode terminal 208 formed on the other main surface of the container body 201 are conductive. A conductive bonding material 207 such as an adhesive or solder is applied, an integrated circuit element is mounted on an integrated circuit element mounting pad, and a conductor 204 is mounted on each conductor connection electrode terminal 208 of the container body 201. Then, by performing the heat treatment, the integrated circuit element 203 is bonded to the integrated circuit element mounting pad 209, and the conductor 204 is bonded to the conductor connecting electrode terminal 208.

JP 2003-46251 A

However, in the conventional piezoelectric oscillator, the conductor connecting electrode terminal 208 and the integrated circuit element mounting pad 209 are connected on the main surface by a wiring pattern.
A conductive bonding material 207 such as a conductive adhesive or solder is applied to the integrated circuit element mounting pad 209 and the conductor connecting electrode terminal 208 formed on the other main surface of the container body 201, and the integrated circuit element 203 When the conductor 204 is mounted on the integrated circuit element mounting pad 209 and the conductor connecting electrode terminal 208 of the container 201 and heat treatment is performed after mounting, the molten conductive material on the integrated circuit element mounting pad 209 and the conductor connecting electrode terminal 208 is obtained. The conductive bonding material 207 flows out into the wiring pattern. As a result, there is a problem that the amount of the conductive bonding material 207 for connecting the integrated circuit element 203 and the conductor 204 is reduced.

  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 and the conductor connection electrode terminal from being reduced, the integrated circuit element and the terminal portion are provided. It is an object of the present invention to provide a piezoelectric oscillator that can prevent a decrease in connection strength.

  The piezoelectric oscillator of the present invention is made to solve the above-mentioned problems, and includes a container body having a recessed space on one main surface, a piezoelectric vibration element mounted in the recessed space, and a container body. A piezoelectric oscillator comprising an integrated circuit element mounted on the other main surface, a terminal portion, and a lid that hermetically seals the recessed space, and is provided at the four corners of the other main surface of the container body An electrode terminal for connection and an integrated circuit element mounting pad provided at the center are provided, and the electrode terminal for connecting terminal part and the integrated circuit element mounting pad are formed by a wiring pattern formed on the other main surface of the container body. In addition to being connected, an insulating layer is formed on the wiring pattern.

  The insulating layer is made of aluminum oxide or quartz glass.

  In addition, the insulating layer is formed along a side surface of the terminal portion facing the integrated circuit element.

According to the piezoelectric oscillator of the present invention, the insulating layer is provided on the wiring pattern that connects the terminal portion connection electrode terminal and the integrated circuit element mounting pad. Can be kept on.
Accordingly, a certain amount of the conductive bonding material on the terminal portion connection electrode terminal and the integrated circuit element mounting pad necessary for connecting the integrated circuit element and the terminal portion can be secured. It is possible to prevent the connection strength from being lowered.

  Further, since the insulating layer is made of aluminum oxide or quartz glass, a plurality of insulating layers can be formed by screen printing means.

  In addition, when the terminal layer is mounted on the terminal portion connection electrode terminal of the container body by providing the insulating layer at a position along the side surface of the terminal portion facing the integrated circuit element, The terminal part can be positioned at a predetermined position on the other main surface of the container body, and when the terminal part is in contact with the integrated circuit element during mounting, the integrated circuit element is damaged or the integrated circuit element is disposed. It is possible to prevent displacement.

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.

(First embodiment)
FIG. 1 is an exploded perspective view showing a piezoelectric oscillator according to a first embodiment of the present invention. 2 is a cross-sectional view taken along the line AA in FIG. FIG. 3A is a bottom view of a container body constituting the piezoelectric oscillator according to the first embodiment of the present invention, and FIG. 3B is a container of the piezoelectric oscillator according to the first embodiment of the present invention. It is a bottom view which shows an example of the state which provided the terminal part in the body.

  The piezoelectric oscillator 100 shown in FIG. 1 to FIG. 3 mainly includes a piezoelectric vibrator 90 including a container body 10, a piezoelectric vibration element 20, and a lid body 30, an integrated circuit element 50, and a terminal portion 41. In the piezoelectric oscillator 100, a concave space 14 is formed on one main surface of the container body 10, a piezoelectric vibration element 20 is mounted in the concave space 14 of the container body 10, and the other main surface of the container body 10. In the structure, the integrated circuit element 50 is mounted and the terminal portion 41 is provided.

The piezoelectric vibration element 20 is formed by applying an excitation electrode 21 to a quartz base plate as shown in FIGS. 1 and 2, and an alternating voltage from the outside is applied to the quartz base plate via the excitation electrode 21. Then, excitation is generated 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 is composed of 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 formed in the recessed space 14 of the container body 10. It is mounted in the recessed space 14 by being connected by being electrically and mechanically connected via 70 (see FIG. 2).

  Further, as shown in FIG. 1, the integrated circuit element 50 is provided with an oscillation circuit for generating an oscillation output from the piezoelectric vibration element 20 on the circuit forming surface, and an output signal generated by the oscillation circuit is a terminal portion. The signal is output to the outside of the piezoelectric oscillator 100 via a predetermined terminal of 41 and used as a reference signal such as a clock signal, for example. The integrated circuit element 50 is mounted on integrated circuit element mounting pads 15a and 15b formed on the other main surface of the container body 10 to be described later.

As shown in FIGS. 1 and 2, the container body 10 is formed by laminating a plurality of insulating layers made of a ceramic material such as alumina ceramics or glass-ceramic, and one main surface of the container body 10. In the central region, a concave space 14 is formed. Further, an annular sealing conductor pattern 11 is formed on the entire circumference of the opening side top surface of the side wall portion of the container body 10 surrounding the recessed space 14. A piezoelectric vibration element mounting pad 13 is provided in the recessed space 14.
On the other main surface of the container body 10, as shown in FIG. 3, a monitor electrode terminal 16 is provided at the center.
Integrated circuit element mounting pads 15 a and 15 b for mechanically bonding the integrated circuit element 50 are provided around the monitor electrode terminal 16.
At the four corners of the other main surface of the container body 10, terminal portion connection electrode terminals 12 for mechanically joining the terminal portions 41 are provided.
The integrated circuit element mounting pad 15 a and the terminal portion connecting electrode terminal 12 are connected by a wiring pattern 17 formed on the other main surface of the container body 10. An insulating layer 18 is provided on the wiring pattern 17.

The sealing conductor pattern 11 may be provided so as to cover the inner side surface and the outer side surface of the side wall portion that forms the recessed space 14.
The sealing conductor pattern 11 is used when a lid 30 described later is joined to the container body 10, and improves the wettability of the sealing member 31 formed on the lid 30. Thereby, the airtight reliability and productivity of the recessed space 14 can be improved.

  The piezoelectric vibration element mounting pad 13 connected to the excitation electrode 21 is an integrated circuit formed on a wiring conductor (not shown), a via-hole conductor (not shown), etc. inside the container body 10 and an inner bottom surface of the recessed space 14. It is electrically connected to the integrated circuit element 50 via the element mounting pads 15a and 15b.

  As shown in FIG. 3, the integrated circuit element mounting pads 15 a and 15 b are provided around the monitor electrode terminal 16 provided at the center of the other main surface 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. The electronic circuit in the integrated circuit element 50 is electrically connected to the crystal resonator element 20 via a wiring conductor (not shown), a via-hole conductor (not shown) or the like formed inside the container body 10. .

The terminal portion connection electrode terminals 12 are provided at the four corners of the other main surface of the container body 10 as shown in FIG.
The terminal portion connection electrode terminal 12 is mechanically and electrically joined to a metal film layer 43a formed on the terminal portion 41, which will be described later, by a conductive bonding material 60 such as solder or a conductive adhesive. .

As shown in FIG. 3A, the monitor electrode terminal 16 is provided at the center of the other main surface of the container body 10 and is formed in a shape larger than the integrated circuit element mounting pad 15. .
The monitor electrode terminal 16 is connected to the piezoelectric vibration element 20 via a piezoelectric vibration element mounting pad 13 formed on the bottom surface of the concave space 14 of the container body 10, and the piezoelectric vibration element 20. It is used to measure electrical characteristics such as CI (crystal impedance) value and resonance frequency value.

The insulating layer 18 is made of aluminum oxide or quartz glass. The insulating layer 18 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 18 is formed by screen printing and baking on the wiring pattern 17 that connects the integrated circuit element mounting pads 15a and the terminal portion connection electrode terminals 12 provided at four locations.
The insulating layer 18 is formed over the other main surface of the container body 10 so as to straddle the wiring pattern 17 along the side surface of each terminal portion 41 facing the integrated circuit element 50 when the terminal portion 41 is mounted. Thus, when the terminal portion 41 is mounted on the terminal portion connection electrode terminal 12 of the container body 10, the terminal portion 41 is positioned at a predetermined position on the other main surface of the container body 10 by the insulating layer 18. In addition, it is possible to prevent damage to the integrated circuit element 50 and displacement of the integrated circuit element 50 by bringing the terminal portion 41 into contact with the integrated circuit element 50 during mounting.
Moreover, the thickness dimension of the insulating layer 18 is 10-100 micrometers. When the thickness dimension of the insulating layer 18 is 10 μm or more, the conductive bonding material 60 can be prevented from flowing onto the wiring pattern 17.
Further, by setting the thickness of the insulating layer 18 to 50 to 100 μm, the terminal portion 41 can be positioned by the insulating layer 18 and the terminal portion 41 faces the inside of the other main surface of the container body at the time of joining. Therefore, the terminal layer 41 can be prevented from coming into contact with the integrated circuit element 50.
When the thickness dimension of the insulating layer 18 is 100 μm or more, the flatness of the other main surface of the container body 10 is lost, and when the crystal resonator element 20 is mounted, the container body 10 is moved, so that the stable. The crystal resonator element 20 could not be mounted.
The width dimension corresponding to the parallel direction with respect to the wiring pattern 18 of the insulating layer 18 is 100 to 200 μm.

The terminal portion 41 is formed of a single plate such as silicon, glass or glass epoxy resin by a conventionally known punching method or etching method.
The terminal portion 41 has a columnar shape having a height dimension higher than that of the integrated circuit element 50.
The terminal portion 41 extends from the side surface of the plurality of through-hole portions provided on the flat substrate toward the inner surface of the opposing through-portion portion, and is connected to the terminal portion connection formed on the other main surface of the container body 10. Metal film layers 42a and 42b plated with Ni and Au are formed on the surfaces of the plurality of terminal portions 41 provided at positions corresponding to the electrode terminals 12 in the same direction as both main surfaces of the substrate, and the terminals The part 41 is formed separately.
The metal film layer 42a and the metal film layer 42b are electrically connected to each other by wirings or via holes formed inside or on the surface of the terminal portion 41.

  As described above, since the terminal portion 41 is formed by processing the substrate, when mounting on an external electric circuit such as a mother board as an external connection electrode terminal of the container body 10, a conductive bonding material such as solder is used. Even when electrically connected to the circuit wiring of the external electric circuit, the conductive bonding material does not crawl onto the surface of the terminal portion 41, so that it is possible to prevent a short circuit with other terminal portions or the integrated circuit element 50. .

  Here, of the four external connection electrode terminals 41a, if the ground terminal and the oscillation output terminal 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. be able to. Therefore, it is preferable to arrange the ground terminal and the oscillation output terminal close to each other.

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

  The conductive adhesive 70 contains a conductive filler in a silicone resin, and examples of the conductive powder include 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.

  When the container body 10 is made of alumina ceramics, a sealing conductor pattern 11 and terminal portion connection electrodes are formed 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 the terminal 12, the piezoelectric vibration element mounting pad 13, the integrated circuit element mounting pad 15, the wiring pattern 17 and the like is also punched into the ceramic green sheet, and a via is formed in a through hole that has been previously drilled. A conductor paste to be a conductor is applied by well-known screen printing, and a plurality of these are laminated, press-molded, and then fired at a high temperature.

  The sealing conductor pattern 11 includes, for example, a nickel (Ni) layer and a gold (Au) layer sequentially on the surface of a base layer made of tungsten (W), molybdenum (Mo), etc., and surrounds the recess space 14 in an annular shape. By making it adhere in the form which does, it is formed in the thickness of 10 micrometers-25 micrometers.

  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.

(Second Embodiment)
FIG. 4 (a) is a bottom view of a container body constituting a piezoelectric oscillator according to the second embodiment of the present invention, and FIG. 3 (b) is a piezoelectric oscillator according to the second embodiment of the present invention. It is a bottom view which shows an example of the state which provided the terminal part in the container body.
The insulating layer 18 is provided so as to straddle the two wiring patterns 17 along the short side of the other main surface of the container body 10.
By doing in this way, it becomes possible to form the insulating layer 18 collectively.

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 quartz resonator element using quartz as the piezoelectric material constituting the piezoelectric resonator element 20 has been described. However, as other piezoelectric materials, lithium niobate, lithium tantalate, or piezoelectric ceramics is piezoelectric. A piezoelectric vibration element used as a material may be used.

  In the present embodiment, the terminal portion 41 has been described as an insulating member such as silicon, glass, or a glass epoxy resin. However, a metal member such as copper may be used.

In addition, as shown in FIG. 5, the terminal portion 42 may be formed like a pair of legs, and may be arranged in parallel with the IC element 7 sandwiched between the legs.
In addition, a metal film 42a corresponding to the terminal portion connection electrode terminal formed on the container body is formed on one main surface of the pair of leg portions 43a and 43b, and four metals are formed on the other main surface of the leg portion. The film 42b (power supply voltage terminal, ground terminal, oscillation output terminal, oscillation control terminal) is divided into two legs 43a and 43b, and two films 42b are provided.
When the leg portions 43a and 43b are made of glass cloth base epoxy resin, a glass cloth base formed by weaving glass yarn is impregnated with a liquid precursor of epoxy resin, and the precursor is polymerized at a high temperature. A base is formed by attaching a metal foil such as a copper foil to the surface of the base, and a conventionally known photoetching or the like is employed, and the metal foil is processed into a predetermined pattern to form a wiring conductor. .

1 is an exploded perspective view showing a piezoelectric oscillator according to a first embodiment of the present invention. It is AA sectional drawing of FIG. FIG. 3B is a bottom view of the container constituting the piezoelectric oscillator according to the first embodiment of the present invention, and FIG. 3B is a diagram illustrating a case where a terminal portion is provided on the container of the piezoelectric oscillator according to the first embodiment of the present invention. It is a bottom view which shows an example of a state. (A) is a container bottom view which comprises the piezoelectric oscillator which concerns on the 2nd Embodiment of this invention, (b) is a terminal part in the container of the piezoelectric oscillator which concerns on the 2nd Embodiment of this invention. It is a bottom view which shows an example of the state which provided. It is a disassembled perspective view which shows the piezoelectric oscillator which concerns on other embodiment of this invention. It is sectional drawing which shows the crystal oscillator which is an example of the conventional piezoelectric oscillator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Container body 11 ... Conductive pattern for sealing 12 ... Electrode terminal for terminal part connection 13 ... Piezoelectric vibration element mounting pad 14 ... Recessed space 15a, 15b ... Integrated circuit element mounting Pad 16 ... Monitor electrode terminal 17 ... Wiring pattern 18 ... Insulating layer 20 ... Piezoelectric vibration element 21 ... Excitation electrode 30 ... Cover body 31 ... Sealing member 40 ..Substrate 41 ... Terminal part 41a ... External connection electrode terminal 42a, 42b ... Metal film layer 43a 43b ... Leg part 50 ... Integrated circuit element 60 ... Conductive bonding material 70 ... Conductive adhesive 90 ... Piezoelectric vibrator 100 ... Piezoelectric oscillator

Claims (3)

A container body having a recessed space on one main surface;
A piezoelectric vibration element mounted in the recessed space;
An integrated circuit element and a terminal portion mounted on the other main surface of the container body;
A piezoelectric oscillator comprising a lid for hermetically sealing the recessed space,
The terminal part connection electrode terminals provided at the four corners of the other main surface of the container body, and the integrated circuit element mounting pad provided at the center part are provided,
The terminal part connection electrode terminal and the integrated circuit element mounting pad are connected by a wiring pattern formed on the other main surface of the container body, and an insulating layer is formed on the wiring pattern. A piezoelectric oscillator characterized by comprising:   2. The piezoelectric oscillator according to claim 1, wherein the insulating layer is made of aluminum oxide or quartz glass.   3. The piezoelectric oscillator according to claim 1, wherein the insulating layer is formed along a side surface of the terminal portion facing the integrated circuit element.

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