JP2008085961A - Piezoelectric oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric oscillator that can inspect a piezoelectric oscillation element easily for improving productivity and workability even after assembly, and can be thinned. <P>SOLUTION: In the piezoelectric oscillator, an element mount pad is formed on a bottom surface in the recessed space in a rectangular vessel, the piezoelectric oscillation element and an integrated circuit element for oscillation are mounted onto the element mount pad, a rectangular lid for covering the opening of the vessel is arranged at the sidewall top of the vessel, the lid is fixed to a conductor pattern for sealing provided at the sidewall top, and the piezoelectric vibration element in the vessel and the integrated circuit element for oscillation are sealed airtightly. In this case, on the sidewall top surface between the periphery-side edge of the conductor pattern for sealing and that of the sidewall top, there is an electrode terminal for monitors connected to the piezoelectric vibration element electrically. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

   In the present invention, among piezoelectric devices that are one of electronic components used in electronic devices such as portable communication devices, a container body includes at least a piezoelectric vibration element and an oscillation circuit that is electrically connected to the piezoelectric vibration element. The present invention relates to a piezoelectric oscillator on which an integrated circuit element is mounted.

   Conventionally, an electronic device such as a portable communication device is equipped with a piezoelectric oscillator, which is one of the electronic components, as a source for generating a reference operation signal, a clock signal, or the like of an electronic device mounted on an electric device or an electronic device. .

   As an explanation of such a conventional piezoelectric oscillator, FIG. 5 illustrates an embodiment of a conventional piezoelectric oscillator. That is, a rectangular plate-shaped piezoelectric vibration element (not shown) made of quartz, lithium tantalate, lithium niobate or piezoelectric ceramics is formed in a recessed space (not shown) formed in the container body 101 made of a ceramic material or the like. Is mounted in such a way that it is held only on one short side. Further, an integrated circuit element (not shown) including at least an oscillation circuit electrically connected to the piezoelectric vibration element is mounted together. Furthermore, a metal lid 102 is placed and fixed on the container body 100 to hermetically seal the recessed space in which the piezoelectric vibration element and the integrated circuit element are mounted, and the piezoelectric oscillator 100 is configured (for example, Patent Document 1). reference.). In addition, the piezoelectric oscillator 100 is mounted on the side surface of the container body 101 in order to measure electrical characteristics such as a resonance frequency value and a crystal impedance (hereinafter referred to as CI) value of the piezoelectric vibration element. At least two monitor electrode terminals 103 electrically connected to the element are provided. (For example, see Patent Document 2).

The following prior art documents are disclosed about the piezoelectric oscillator of the above-mentioned form.
JP 2004-15441 A JP 2004-215799 A JP 2001-119244 A JP 2002-280835 A

   In addition, the applicant did not come to discover prior art documents related to the present invention by the time of the filing of the application other than the prior art documents specified by the prior art document information described above.

   In the conventional piezoelectric oscillator described above, after the assembly of the piezoelectric oscillator is completed, the CI characteristic of the piezoelectric vibration element is measured by an electrical characteristic measuring instrument such as an impedance analyzer, thereby performing an electrical characteristic inspection as the piezoelectric oscillator. The quality of the piezoelectric oscillator is determined. For this reason, the monitor electrode terminals are deposited on the side surfaces of the container body. However, as the piezoelectric oscillator is made thinner, it is necessary to reduce the surface area of the monitor electrode terminals formed on the side surfaces of the container body. It was. However, since the surface area is reduced, it has become difficult to bring the measurement contact pin of the electrical property measuring instrument into contact with the monitor terminal electrode. Therefore, there has been a problem that the workability and efficiency of the inspection due to poor contact are significantly reduced.

   In addition, since it is necessary to provide a monitor electrode terminal having a size capable of measurement on the outer surface of the piezoelectric oscillator, the monitor electrode terminal may hinder the thinning of the piezoelectric oscillator.

   The present invention has been devised in view of the above problems, and its purpose is to improve the productivity and workability by being able to easily inspect the piezoelectric vibration element even after assembly. Another object of the present invention is to provide a piezoelectric oscillator that can be made thinner.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and a rectangular parallelepiped container body having a substantially rectangular main surface is formed with a recessed space having an opening on one main surface of the container body. An element mounting pad is formed on the inner bottom surface of the recess space, and a piezoelectric vibration element and an integrated circuit element are mounted on the element mounting pad, and a container on the top of the side wall of the container body surrounding the recess space A rectangular lid that covers the opening of the body is disposed, and the lid and the sealing conductor pattern provided on the top of the side wall are fixed to hermetically seal the piezoelectric vibration element and the integrated circuit element in the container. In the piezoelectric oscillator formed by
A monitor electrode terminal electrically connected to the piezoelectric vibration element is provided on the surface of the side wall top portion between the outer peripheral side end portion of the sealing conductor pattern and the outer peripheral side end portion of the side wall top portion. This is a piezoelectric oscillator.

   In the piezoelectric oscillator as described above, at least two monitor electrode terminals may be formed diagonally on the tops of the opposite side walls of the container body with the recessed space interposed therebetween. .

   According to the piezoelectric oscillator of the present invention, the electricity of the piezoelectric vibration element is formed on the surface of the side wall top between the outer peripheral end of the sealing conductor pattern provided on the top of the side wall of the container body and the outer peripheral end of the side wall top. Monitor electrode terminal for measuring the electrical characteristics, so that when measuring the electrical characteristics of the piezoelectric vibration element, the monitor electrode terminal is of a size that can reliably contact the contact pins of the electrical property measuring instrument This makes it possible to improve inspection workability, inspection efficiency, and productivity. Moreover, since it is not necessary to form the monitor electrode terminal on the outer side surface of the container body, there is no need for a space for forming the monitor electrode terminal on the outer side surface of the container body, and the piezoelectric oscillator can be made thinner. Become.

   Further, when the piezoelectric vibration element and the integrated circuit element are mounted in the recessed space of the container body, the respective elements must be arranged with high accuracy at predetermined positions on the element mounting pad. In one embodiment of the piezoelectric oscillator according to the present invention, the monitor electrode terminal is opposed to the outer wall top surface between the outer peripheral end of the sealing electrode pattern and the outer peripheral end of the outer wall with the recess space opening interposed therebetween. Further, the monitor electrode terminal is relatively close to the mounting position of the piezoelectric vibration element and the integrated circuit element in the recessed space, and when the piezoelectric vibration element and the integrated circuit element are mounted. Since the monitor electrode terminal is used as a reference mark for mounting positioning of the piezoelectric vibration element and the integrated circuit element, the piezoelectric vibration element and the oscillation circuit are oscillated. It becomes possible to improve the mounting accuracy of the integrated circuit element.

   Therefore, according to the present invention, the mounting work of the piezoelectric vibration element and the integrated circuit element and the characteristic inspection of the piezoelectric vibration element mounted inside can be easily and easily performed, thereby improving the productivity and workability. An object of the present invention is to provide a piezoelectric oscillator that can be made thin and can be made thin.

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is an exploded perspective view illustrating a piezoelectric oscillator according to an embodiment of the present invention as an example. FIG. 2 is a schematic cross-sectional view showing a form after the piezoelectric oscillator shown in FIG. 1 is assembled. In each figure, the same reference numerals indicate the same parts, and a part of the structure is not shown for clarity. In addition, some of the illustrated dimensions are exaggerated.
In these drawings, the piezoelectric oscillator shows a material using a crystal, which is one of piezoelectric materials, as a material of a piezoelectric vibration element mounted therein, and is formed inside a container body 10 having a rectangular main surface shape. In the recessed space 11, the piezoelectric vibration element 20 and an integrated circuit element 30 incorporating an oscillation circuit and a frequency adjusting circuit electrically connected to the piezoelectric vibration element 20 are housed. Is a hermetically sealed structure.

   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 the container body 10 has a rectangular opening in the central region on the upper main surface. An annular sealing conductor pattern 12 is formed on the entire circumference of the opening-side top surface of the side wall of the container body 10 in which the recessed space 11 that surrounds the opening of the recessed space 11. A monitoring electrode terminal 16 for measuring electrical characteristics such as CI and resonance frequency of the piezoelectric vibration element 20 is provided on the side wall top surface between the outer peripheral side end of the sealing conductor pattern 12 and the side wall top end. Is provided. In the present invention, among the plurality of insulating layers constituting the container body 10, the container body 10 can be formed in a form in which the insulating layer in which the monitor electrode terminal is formed on the outer side surface of the side wall of the conventional container body is omitted. Can be realized.

   A plurality of external connection electrode terminals 13 including a power supply voltage terminal, an output terminal, and a ground terminal are provided on the external mounting side main surface (lower main surface) of the container body 10. The container body 10 is for mounting the piezoelectric vibration element 20 and the integrated circuit element 30 made of quartz, which is one of the piezoelectric materials, in the recessed space 11 opened on the upper main surface side. In the recessed space 11 of the body 10, an integrated circuit element mounting pad 14 for mounting an integrated circuit element and excitation electrodes 21 formed on both front and back main surfaces of the piezoelectric vibration element 20 are electrically connected to each other. The piezoelectric vibration element mounting pad 15 to be applied is deposited.

   The integrated circuit element mounting pad 14 is electrically connected to the oscillation integrated circuit element 30, and the power supply voltage terminal and the output of the external connection electrode terminal 13 through a wiring conductor, a via-hole conductor or the like inside the container body 10. Electrically connected to the terminal. Further, the piezoelectric vibration element mounting pad 15 is electrically connected to the excitation electrode 21 formed on the piezoelectric vibration element 20 via the conductive adhesive 40, and the wiring conductor inside the container body 10, the via hole conductor, etc. And is electrically connected to the integrated circuit element 30. Furthermore, the piezoelectric vibration element mounting pad 15 is also electrically connected to the monitor electrode terminal 16 via a wiring conductor, a via-hole conductor, or the like inside the container body 10.

   Further, the sealing conductor pattern 12 formed on the top surface of the recess 10 on the side wall of the container body 10 has a nickel (Ni) layer on the surface of a base layer made of tungsten (W), molybdenum (Mo), or the like. And a gold (Au) layer are formed in a thickness of 10 μm to 25 μm by sequentially depositing the container body 10 so as to surround the annular shape of the container body 10, and the sealing conductive pattern 12 includes a lid body 50 described later. In order to join the upper surface of the container body 10 through the sealing member 51 formed on the lid 50, the sealing conductor pattern 12 is formed of a base layer made of W or Mo as described above. The structure in which the Ni layer and the Au layer are sequentially deposited on the surface improves the wettability of the sealing member 51 with respect to the sealing conductor pattern 12, and improves the hermetic reliability and productivity of the piezoelectric oscillator. Improve.

   In addition, a via conductor (not shown) has one end connected to the sealing conductor pattern 12 of the container body 10 and the other end connected to the external connection electrode terminal 13 of the container body 10 inside the container body 10. The lid 50 is joined to the sealing conductor pattern 12 via the sealing member 51 on the sealing conductor pattern 12 deposited on the opening-side top surface of the side wall of the container body 10. Is electrically connected to the ground terminal among the external connection electrode terminals 13 formed on the lower surface of the container body 10 via the via conductor. As described above, since the lid 50 made of a metal material is electrically connected to the ground terminal of the external connection electrode terminal 13, the lid 50 becomes a ground potential when the piezoelectric oscillator is used. In addition, the piezoelectric shield element 20 and the oscillation integrated circuit element 30 can be well protected by an unnecessary electrical action from the outside by the electromagnetic shielding action of the lid 50. The external connection electrode terminal 13 on the mounting side main surface of the container body 10 including such a ground terminal is used when the piezoelectric oscillator is mounted on an external wiring board such as a mother board, and the wiring of the external wiring board and solder or metal bumps. It functions as an electrode terminal for electrical connection through a bonding material having electrical conductivity.

   The monitor electrode terminal 16 formed on the side wall opening side top surface of the container body 10 surrounding the recessed space 11 is formed so that the exposed main surface has a rectangular shape, so that the piezoelectric oscillator can be assembled. After completion, when the CI characteristic of the piezoelectric vibration element 20 mounted in the recessed space 11 is measured by the electric characteristic measuring instrument, the contact pin of the electric characteristic measuring instrument is formed in a size that can be contacted easily and reliably. .

   In addition, as an electrical characteristic measuring instrument used for measuring the impedance characteristics of the piezoelectric vibration element 20, a network analyzer capable of measuring equivalent parameters such as inductance and capacitance in addition to the resonance frequency and crystal impedance of the piezoelectric vibration element 20. Alternatively, an impedance analyzer or the like is used, and the contact pins are made of a highly conductive pin with a gold plating on the surface of an alloy such as copper or silver, and a re-sectorable socket with a spring property that suppresses impact during contact. The measurement is performed by contacting the electrode terminal 16 while pressing it against the monitor electrode terminal 16.

   When the container body 10 is made of alumina ceramics, a sealing conductor pattern 12 is provided on the surface of a ceramic green sheet obtained by adding and mixing a suitable organic solvent to a predetermined ceramic material powder. A through-hole previously punched by punching the ceramic green sheet with a conductive paste to be used as the electrode terminal 13, the integrated circuit element mounting pad 14, the piezoelectric vibration element mounting pad 15, the monitor electrode terminal 16 and the like It is manufactured by applying a conductor paste to be a via conductor therein by well-known screen printing, laminating a plurality of them and press-molding them, followed by firing at a high temperature.

   On the other hand, when the piezoelectric vibration element 20 accommodated in the recessed space of the container body 10 uses, for example, quartz as the material of the piezoelectric material constituting the piezoelectric vibration element 20, the crystal base plate is It is cut out at a cut angle and is subjected to external shape processing. It is substantially flat and has a square planar shape, and a pair of excitation electrodes 21 are attached to and formed on the front and back main surfaces of the quartz base plate. When an alternating voltage is applied to the quartz base plate via the excitation electrode 21, excitation occurs in a predetermined vibration mode and frequency. Such a piezoelectric vibration element 20 electrically connects the excitation electrode 21 applied to both main surfaces thereof and the corresponding piezoelectric vibration element mounting pad 15 on the bottom surface of the recessed space 11 through the conductive adhesive 40. It is mounted in the recessed space 11 by connecting mechanically and mechanically.

   The circuit forming surface of 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, and an output signal generated by the oscillation circuit is output from the output terminal of the external connection electrode terminal 13. It is output to the outside and used as a reference signal such as a clock signal.

   The conductive adhesive 40 contains a conductive filler in a silicone resin. 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 combinations thereof are used.

   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 position 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 deformation | transformation, change, improvement, etc. are possible in the range which does not deviate from the summary of this invention. For example, as shown in FIGS. 3 and 4, two monitor electrode terminals 16 out of the three monitor electrode terminals 16 are formed in a recessed space at the tops of the opposite side walls of the container body 10. 11 is formed in a diagonal form with 11 therebetween. The electrode terminal for monitoring formed in such a form is relatively close to the mounting position of the piezoelectric vibration element and the integrated circuit element in the recess space, and when mounting the piezoelectric vibration element and the integrated circuit element, the piezoelectric vibration element In addition, since the electrode terminal for monitoring can be used as a reference mark for positioning the piezoelectric vibration element and the integrated circuit element, the piezoelectric vibration element 20 and the integrated circuit element 30 can be used. It becomes possible to improve the mounting position accuracy.

FIG. 1 is an exploded external perspective view showing an embodiment of a piezoelectric oscillator according to the present invention. FIG. 2 is a schematic cross-sectional view showing the piezoelectric oscillator shown in FIG. 1 assembled and then cut at the position of the virtual cutting line AA ′ shown in FIG. FIG. 3 is an exploded external perspective view illustrating another embodiment of the present invention as an example. FIG. 4 is a schematic cross-sectional view showing the piezoelectric oscillator shown in FIG. 3 assembled and then cut at the position of the virtual cutting line BB ′ shown in FIG. FIG. 5 is an external perspective view showing an embodiment of a 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 14 ... Integrated circuit element mounting pad 15 ... Piezoelectric vibration element mounting pad 16. ..Monitor electrode terminals 20 ... Quartz vibration element (piezoelectric vibration element)
DESCRIPTION OF SYMBOLS 21 ... Electrode for excitation 30 ... Integrated circuit element 40 ... Conductive adhesive material 50 ... Lid 51 ... Sealing member

Claims (2)

In a rectangular parallelepiped container body having a substantially rectangular main surface shape, a concave space having an opening is formed on one main surface of the container body, and an element mounting pad is formed on the bottom surface in the concave space, A piezoelectric vibration element and an integrated circuit element are mounted on the element mounting pad, and a rectangular lid that covers the opening of the container body is disposed on the top of the side wall of the container body that surrounds the recessed space. In the piezoelectric oscillator formed by fixing the lid and the sealing conductor pattern provided on the top of the side wall and hermetically sealing the piezoelectric vibration element and the integrated circuit element in the container body,
A monitor electrode terminal electrically connected to the piezoelectric vibration element is provided on the surface of the side wall top between the outer peripheral side end of the sealing conductor pattern and the outer peripheral side end of the side wall top. A piezoelectric oscillator characterized by that.   2. The piezoelectric oscillator according to claim 1, wherein at least two electrode terminals for monitoring are formed on the tops of the two opposite side walls of the container body in a diagonal form across the recessed space.

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