JP2008219095A - Piezoelectric oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric oscillator which improves connection strength by increasing the area of an electrode terminal for external connection, and outputs a stable oscillation frequency. <P>SOLUTION: The piezoelectric oscillator has: a vessel body having a recessed space on one main surface; piezoelectric vibration and integrated circuit elements mounted in the recessed space; and a lid body for sealing the recessed space airtightly. There are provided: a first electrode terminal for external connection at the center of the other main surface of the vessel body; a second electrode terminal for external connection surrounding the first electrode terminal for external connection; a third electrode terminal for external connection surrounding the second electrode terminal for external connection; and a fourth electrode terminal for external connection surrounding the third electrode terminal for external connection. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

FIG. 4 is an exploded perspective view showing a conventional piezoelectric oscillator. As shown in FIG. 4, the conventional piezoelectric oscillator 200 mainly includes a container body 201 having a recessed space 205, a piezoelectric vibration element 202, an integrated circuit element 203, and a lid body 204.
The container body 201 is formed of a substantially rectangular parallelepiped made of a ceramic material or the like, and a recessed space 205 is formed in one main surface. A mounting portion 206 is formed in the recessed space at a position higher than the bottom surface in the recessed space. ing.
The piezoelectric vibration element 202 is mounted on a piezoelectric vibration element mounting pad formed in the mounting portion 206.
The integrated circuit element 203 is mounted on an integrated circuit element mounting pad formed on the bottom surface in the recessed space of the container body 201.
The lid 204 is placed on the concave space of the container body 201 and fixed to the top of the side wall of the container body 201, whereby the inside of the concave space is hermetically sealed.
In such a piezoelectric oscillator 200, a power supply voltage terminal, a ground terminal, an oscillation output terminal, and an oscillation control terminal, which are external connection electrode terminals, are formed at the four corners of the other main surface of the container body 201. Is known (see, for example, Patent Document 1).

JP 2002-111435 A (page 5-6, FIG. 2)

However, when the conventional piezoelectric oscillator 200 is reduced in size, the area of the external connection electrode terminal formed on the other main surface of the container body 201 is reduced, so that the connection area is reduced. Therefore, with a small connection area, there is a possibility that the connection strength that can withstand an impact such as dropping cannot be maintained.
When mounted on an external wiring board such as a mother board, there is a problem that connection strength is reduced.

  Further, since the connection strength of the external connection electrode terminals including the power supply voltage terminal is lowered, the driving of the integrated circuit element 203 mounted on the container body 201 becomes unstable, and a stable oscillation frequency is output. There was also a problem that could not be done.

  Further, the external connection electrode terminals formed at the four corners of the other main surface of the container body 201 are close to each other, and noise is superimposed on the oscillation output terminal which is one of the external connection electrode terminals. There was also a problem.

  The present invention has been made in view of the above problems, and provides a piezoelectric oscillator capable of increasing the area of an external connection electrode terminal to improve connection strength and outputting a stable oscillation frequency. Is an issue.

  The present invention has been made to solve the above problems, and includes a container body having a recessed space on one main surface, a piezoelectric vibration element and an integrated circuit element mounted in the recessed space, and the recessed space. A piezoelectric oscillator including a lid that hermetically seals the first external connection electrode terminal at the center of the other main surface of the container body and a second external electrode that surrounds the first external connection electrode terminal It comprises a connection electrode terminal, a third external connection electrode terminal surrounding the second external connection electrode terminal, and a fourth external connection electrode terminal surrounding the third external connection electrode terminal. It is what.

  The first external connection electrode terminal is an oscillation output terminal, the second external connection electrode terminal is a ground terminal, the third external connection electrode terminal is an oscillation control terminal, and a fourth external connection terminal. The connection electrode terminal is also a power supply voltage terminal.

  Furthermore, the planar shape of the container body is also a square.

According to the piezoelectric oscillator of the present invention, the first external connection electrode terminal at the center of the other main surface of the container body, the second external connection electrode terminal surrounding the first external connection electrode terminal, The other main surface of the container body is provided with a third external connection electrode terminal surrounding the second external connection electrode terminal and a fourth external connection electrode terminal surrounding the third external connection electrode terminal. Since the connection area of the external connection electrode terminals formed on the substrate can be increased, the connection strength to an external wiring board such as a mother board can be improved.
In addition, it is possible to increase the degree of freedom in designing connection pads for mounting a piezoelectric oscillator on an external wiring board such as a mother board.

The first external connection electrode terminal is an oscillation output terminal, the second external connection electrode terminal is a ground terminal, the third external connection electrode terminal is an oscillation control terminal, and a fourth external connection terminal. Since the connection electrode terminal is a power supply voltage terminal, the power supply voltage terminal is disposed on the outermost periphery of the other main surface of the container body, and the connection area of the power supply voltage terminal can be increased. The driving of the integrated circuit element 30 can be stabilized and a stable oscillation frequency can be output.
In addition, the ground terminal that is the second external connection electrode terminal is shaped so as to surround the oscillation output terminal that is the first external connection electrode terminal, so that noise is not superimposed on the oscillation output terminal and stable. It is possible to output the oscillation frequency.

  Since the planar shape of the container body is square, the piezoelectric oscillator can be mounted on an external wiring board such as a mother board without specifying the mounting direction.

Hereinafter, a detailed description of an embodiment of a piezoelectric oscillator according to the present invention will be given with reference to the drawings.
FIG. 1 is an exploded perspective view showing an embodiment of a piezoelectric oscillator according to the present invention. FIG. 2 is a schematic cross-sectional view showing an embodiment of a piezoelectric oscillator according to the present invention. FIG. 3 is an external perspective view of the piezoelectric oscillator according to the present invention as seen from the external connection electrode terminal formation side.

  As shown in FIG. 1 to FIG. 3, a piezoelectric oscillator 100 shows a material using a quartz base plate which is one of piezoelectric materials as a material used for a piezoelectric vibration element 20 mounted inside. The container body 10 having a rectangular shape, the piezoelectric vibration element 20, the oscillation circuit electrically connected to the piezoelectric vibration element 20, and the frequency adjustment are disposed in the recessed space 11 formed on one main surface of the container body 10. The integrated circuit element 30 incorporating an electronic circuit network such as a circuit is mounted, and the recessed space 11 in which the piezoelectric vibration element 20 and the integrated circuit element 30 are mounted is hermetically sealed by a lid 50 described later.

The piezoelectric vibration element 20 is formed by depositing an excitation electrode 21 on a quartz base plate. When an alternating voltage from the outside is applied to the quartz base plate via the excitation electrode 21, a predetermined vibration mode and An excitation is generated at a 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 formed by electrically connecting an excitation electrode 21 attached to both main surfaces of the piezoelectric vibration element 20 and a piezoelectric vibration element mounting pad 15 formed on the upper surface of the mounting portion 16 in the recessed space 11. It is mounted on the stepped portion 16 of the recessed space 11 by being electrically and mechanically connected through the adhesive 40.

  The conductive adhesive 40 contains a conductive filler in a silicone resin, and examples of the conductive powder include aluminum (Al), molybdenum (Mo), tungsten (W), platinum (Pt), Palladium (Pd), silver (Ag), titanium (Ti), nickel (Ni), nickel iron (NiFe), or a combination thereof is used.

Further, the integrated circuit element 30 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 the oscillation circuit passes through the external connection electrode terminal 13. Is output to the outside of the piezoelectric oscillator and used as a reference signal such as a clock signal.
The integrated circuit element 30 is mounted on the integrated circuit element mounting pad 14 formed in the recessed space 11 of the container body 10.

  The container body 10 is formed, for example, by laminating a plurality of insulating layers made of a ceramic material such as alumina ceramics or glass-ceramic, and a rectangular shape opening in the central region is formed on one main surface of the container body 10. The recessed space 11 is formed. An annular sealing conductor pattern 12 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 11. In the recessed space 11, a mounting portion 16 formed at a position higher than the bottom surface of the recessed space 11, a piezoelectric vibration element mounting pad 15 formed in the mounting portion, and an integrated circuit provided on the bottom surface of the recessed space 11. An element mounting pad 12 is provided. Furthermore, an external connection electrode terminal 13 is formed on the other main surface of the container body 10.

  When the container body 10 is made of alumina ceramics, a sealing conductor pattern 12 and external connection electrode terminals are formed on the surface of a ceramic green sheet obtained by adding and mixing a suitable organic solvent to a predetermined ceramic material powder. 13. Conductive paste to be integrated circuit element mounting pad 14, piezoelectric vibration element mounting pad 15 and the like, and conductive paste to be a via conductor in a through-hole previously punched by punching a ceramic green sheet Is manufactured by conventionally known screen printing, and a plurality of these are laminated and press-molded, followed by firing at a high temperature.

  In addition, the sealing conductor pattern 12 formed on the top surface of the side wall portion of the container body 10 includes, for example, a nickel (Ni) layer and gold (Au) on the surface of a base layer made of tungsten (W), molybdenum (Mo), or the like. ) Layers are sequentially deposited in a form surrounding the container body 10 in a ring shape so as to have a thickness of 10 μm to 25 μm. The sealing conductor pattern 12 includes a lid body 50 to be described later. The sealing conductor pattern 12 is bonded to the top surface of the side wall portion of the container body 10 through the sealing member 51 formed on the base member 10 and, as described above, the base layer made of W or Mo is used. By having a structure in which a Ni layer and an Au layer are sequentially deposited on the surface, the wettability of the sealing member 51 with respect to the sealing conductor pattern 12 is improved, and the hermetic reliability and productivity of the piezoelectric oscillator 100 are improved. Improvement Make it.

The mounting portion 16 is formed at a position higher than the bottom surface of the recessed space 11, and a piezoelectric vibration element mounting pad 15 is attached to the mounting portion 16. The piezoelectric vibration element mounting pad 15 is connected to the excitation electrode 21 of the piezoelectric vibration element 20.
Further, the piezoelectric vibration element mounting pad 15 is electrically connected to the integrated circuit element 30 via the wiring conductor and via-hole conductor in the container body 10 and the integrated circuit element connection electrode pad 14 formed on the bottom surface in the recessed space. Connected to.

  The integrated circuit element mounting pad 14 is formed on the bottom surface in the recessed space of the container body 10. The integrated circuit element mounting pad 14 is electrically connected to the connection pad formed in the integrated circuit element 30 electrically and mechanically, and is externally connected via a wiring conductor, a via hole conductor, etc. formed in the container body 10. Of the connection electrode terminals 13, the oscillation output terminal 13a, the oscillation control terminal 13c, and the power supply voltage terminal 13d are electrically connected.

The external connection electrode terminal 13 includes a first external connection electrode terminal at the center of the other main surface of the container body 10, and a second external connection electrode terminal surrounding the first external connection electrode terminal. The third external connection electrode terminal surrounding the second external connection electrode terminal and the fourth external connection electrode terminal surrounding the third external connection electrode terminal are formed.
Therefore, since the connection area of the external connection electrode terminal 13 formed on the other main surface of the container body 10 can be increased, the connection strength to an external wiring board such as a mother board can be improved. In addition, it is possible to increase the degree of freedom in designing connection pads for mounting a piezoelectric oscillator on an external wiring board such as a mother board.

The first external connection electrode terminal 13a is an oscillation output terminal, the second external connection electrode terminal 13b is a ground terminal, and the third external connection electrode terminal 13c is an oscillation control terminal. The fourth external connection electrode terminal 13d is a power supply voltage terminal.
Therefore, since the power supply voltage terminal 13d is disposed on the outermost periphery of the other main surface of the container body 10, the connection area of the power supply voltage terminal 13d can be increased, and thus the integrated circuit element mounted on the container body 10 The drive of 30 is stabilized, and it becomes possible to output a stable oscillation frequency.
In addition, since the ground output terminal 13a is surrounded by the ground terminal 13b, noise is not superimposed on the oscillation output terminal 13a, and a stable oscillation frequency can be output.

  The lid 50 is manufactured by adopting a conventionally well-known metal processing method and molding a metal such as 42 alloy into a predetermined shape, and a nickel (Ni) layer is formed on the upper surface of the lid 50. A gold tin (Au—Sn) layer, which is the sealing member 51, is formed at a location corresponding to the sealing conductor pattern 12 on the upper surface of the nickel (Ni) layer. 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. Moreover, such a sealing member 51 can relieve unevenness of the sealing conductor pattern 12 and prevent a decrease in hermeticity. Further, if the sealing member 51 is too thin, the function is not sufficiently exhibited.

  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, the piezoelectric vibrator using quartz as the piezoelectric material constituting the piezoelectric vibration element has been described. However, the piezoelectric material using lithium niobate, lithium tantalate, or piezoelectric ceramics. It doesn't matter. In addition to the piezoelectric vibrator disclosed in the above embodiment, the present invention can be applied to other piezoelectric devices using a piezoelectric oscillator, a piezoelectric filter, and a surface acoustic wave (SAW) element.

  Moreover, since the planar shape of the container body 10 is square, the container body 10 can be mounted on an external wiring board such as a mother board without specifying the mounting direction.

It is a disassembled perspective view which shows one Embodiment of the crystal oscillator which is an example of the piezoelectric oscillator in this invention. It is sectional drawing which shows one Embodiment of the crystal oscillator which is an example of the piezoelectric oscillator in this invention. It is the external appearance perspective view which looked at the crystal oscillator which is an example of the piezoelectric oscillator in this invention from the electrode terminal side for external connection. It is a schematic sectional drawing which shows the conventional piezoelectric oscillator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Container body 11 ... Recessed space 12 ... Conductive pattern for sealing 13 ... Electrode terminal for external connection 13a ... First electrode terminal for external connection (oscillation output terminal)
13b ... Second external connection electrode terminal (ground terminal)
13c ... Third external connection electrode terminal (oscillation control terminal)
13d: Fourth external connection electrode terminal (power supply voltage terminal)
14 ... Integrated circuit element mounting pad 15 ... Piezoelectric vibration element mounting pad 20 ... Crystal vibration element (piezoelectric vibration element)
DESCRIPTION OF SYMBOLS 21 ... Electrode for excitation 30 ... Integrated circuit element 40 ... Conductive adhesive 50 ... Lid 51 ... Sealing member 100 ... Piezoelectric oscillator

Claims (3)

A piezoelectric oscillator comprising a container body having a recessed space on one main surface, a piezoelectric vibration element and an integrated circuit element mounted in the recessed space, and a lid for hermetically sealing the recessed space,
A first external connection electrode terminal at the center of the other main surface of the container body;
A second external connection electrode terminal surrounding the first external connection electrode terminal;
A third external connection electrode terminal surrounding the second external connection electrode terminal;
And a fourth external connection electrode terminal surrounding the third external connection electrode terminal.   The first external connection electrode terminal is an oscillation output terminal, the second external connection electrode terminal is a ground terminal, the third external connection electrode terminal is an oscillation control terminal, and the fourth 2. The piezoelectric oscillator according to claim 1, wherein the external connection electrode terminal is a power supply voltage terminal.   The piezoelectric oscillator according to claim 1, wherein a planar shape of the container body is a square.

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