JP2006157511A - Quartz oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a quartz oscillator that can be miniaturized, can secure a mounting space, and can be manufactured at lower costs. <P>SOLUTION: The quart oscillator comprises a crystal oscillation element, a base substrate for mounting the crystal oscillation element thereon, and a lid board for performing seal. A step is formed on the outer periphery of the crystal oscillation element, the step being formed with an extraction electrode, and the step is fixed such that it is sandwiched between the base substrate and lid board. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a crystal resonator used as a timing device which is a reference signal for communication equipment, electronic equipment, and the like.

  Conventionally, crystal resonators have been used in electronic devices such as portable communication devices and electronic computers. As such a conventional crystal unit, for example, a pair of electrodes electrically connected to the connection pads via a conductive adhesive on the upper surface of an insulating substrate 21 provided with a pair of connection pads as shown in FIG. A quartz crystal vibration element 23 having a vibration electrode and a seal ring surrounding the previous crystal vibration element 23 are attached, and a quartz lid 24 is joined to the upper portion of the seal ring by seam welding or the like. A structure in which the mounting region 22 of the element 23 is hermetically sealed is known (for example, see Patent Document 1).

Such a crystal resonator has a predetermined value corresponding to the characteristics of the crystal resonator element 24 when an external variable voltage is applied between the vibration electrodes of the crystal resonator element 23 via an input / output terminal provided on the lower surface of the insulating base 21. The thickness-shear vibration is caused at the frequency, and a reference signal having a predetermined frequency is oscillated and output by an external oscillation circuit based on the resonance frequency. Such a reference signal is used as a clock signal in an electronic device such as a portable communication device.
JP 2001-274649 A

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

  However, in the conventional crystal resonator described above, in such a container connection electrode, as a method of establishing electrical continuity with the element connection electrode pad on the insulating substrate side when the crystal resonator element is mounted inside the insulating substrate. A large amount of conductive adhesive for conducting the insulating substrate connecting electrode and the element connecting electrode pad that need to be electrically connected, the insulating gas connecting electrodes on the front and back, the side surface of the crystal vibrating element, and the element connecting Although it may be applied to the electrode pad, it is difficult to apply a large amount of conductive adhesive because the space for mounting the crystal resonator element is extremely narrow due to the miniaturization of the crystal unit. It was.

  Since the quartz resonator element comes into contact with the insulating base and the lid, the frequency characteristics and the like are affected. Therefore, it is necessary to form a cushioning pillow member on the insulating base and the lid, which complicates the manufacturing process. There was a problem that.

  The present invention has been devised in view of the above problems, and it is an object of the present invention to provide a crystal resonator that can cope with downsizing, can secure a mounting space, and can be reduced in cost.

  A crystal resonator according to the present invention is a crystal resonator including a crystal resonator element, a base substrate for mounting the crystal resonator element, and a lid substrate for sealing, the outer periphery of the crystal resonator element A step portion is formed in the portion, an extraction electrode is formed in the step portion, and the step portion, the base substrate, and the lid substrate are fixed so as to be sandwiched therebetween.

  The crystal resonator according to the present invention is characterized in that the step portion of the crystal resonator element is formed on both ends.

  Furthermore, the crystal resonator of the present invention is characterized in that element connection electrodes formed on the crystal resonator element are formed on both main surfaces.

  According to the above-described crystal resonator of the present invention, the step portion is formed in the outer peripheral portion of the crystal resonator element, and the extraction electrode is formed in the step portion. The step portion, the base substrate, and the lid substrate , So that the container connecting electrode can be made narrower due to the miniaturization of the crystal resonator element. Further, by forming the stepped portion, the crystal vibrating element does not come into contact with the base substrate and the lid substrate, and vibration is not hindered, so that a stable frequency can be supplied.

  Further, according to the crystal resonator of the present invention, since the step portions of the crystal resonator element are formed on both ends, it is possible to stably connect in terms of the strength of the crystal resonator element.

  Furthermore, according to the crystal resonator of the present invention, since the element connection electrodes formed on the crystal resonator element are formed on both main surfaces, the base substrate, the lid substrate connection electrode, and the element connection electrode pad are provided. In the case where the conductive adhesive is applied to the base substrate and the lid substrate connecting electrode, the base substrate formed on the main surface of the stepped portion of the crystal vibration element, the lid substrate side main surface, the lid substrate connecting electrode, and the base substrate and the lid. Since it can be limited to the amount used only for the fixed continuity between the element connection electrode pad that can be formed at a position facing the substrate connection electrode, it is effective in miniaturizing a crystal resonator using a crystal resonator element.

Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol in each figure shall show the same object.
FIG. 1 is an exploded perspective view of a crystal resonator according to the present invention. FIG. 2 is a cross-sectional view of the crystal resonator of the present invention. FIG. 3 and FIG. 4 are perspective views illustrating a form in a crystal wafer state when the crystal resonator element according to the present invention is manufactured. FIG. 8 is an exploded perspective view showing another embodiment of the crystal resonator of the present invention shown in FIGS. 5 to 7.
In each drawing, parts or structures that are not necessarily required for this description are not shown. Further, in order to clarify each drawing, some parts or structures are exaggerated, and the thickness dimensions of the parts and structures are particularly exaggerated.

In general, the crystal resonator shown in FIGS. 1 and 2 has an excitation electrode region 2 that is excited at a desired frequency at the center of the crystal resonator element 1. A stepped portion 3 having a thickness greater than that of the portion where the excitation electrode region 2 is formed is formed on the outer peripheral portion thereof, thereby constituting the crystal resonator element 1.
The crystal resonator element 1 shown in FIG. 1 is cut out from a crystal body by so-called AT cut and processed into a flat plate, and the vibration mode of the excitation electrode region 2 is thickness shear vibration. Since the frequency is inversely proportional to the thickness of the portion where the excitation electrode region 2 is formed, it is necessary to reduce the thickness of the excitation electrode region 2 in order to increase the frequency.
In the crystal resonator element 1 processed in such a shape, the excitation electrode 4 on the front and back main surfaces of the excitation electrode region 2, the extraction electrode 5 drawn from the excitation electrode 4, and one side of the outer periphery of the step portion 3. A crystal substrate is formed by forming a base substrate electrically connected to the extraction electrode 5 formed in the vicinity of the edge portion and a lid substrate connection electrode 6.

  The crystal resonator element 1 having such a shape is mounted inside the base substrate 7 and the lid substrate 8 constituting the crystal resonator as shown in FIG. The base substrate 7 and the lid substrate 8 are connected to the base substrate formed in the crystal resonator element 1 on the inner bottom surface of the base substrate 7 and the element connection electrode pad 9 formed at a position corresponding to the lid substrate connection electrode 6 through the conductive adhesive 10. And is firmly connected. At this time, the conductive adhesive 10 is capable of fixing and conducting between the base substrate of the crystal resonator element 1, the base substrate formed on the main surface of the lid substrate, and the lid substrate connecting electrode 6 and the element connecting electrode pad 12. Only applied.

  The base substrate 7 and the lid substrate 8 are multilayer substrates manufactured using a ceramic material such as glass-ceramic or alumina ceramic. A substrate made of a ceramic material is formed by, for example, printing and applying a conductive paste serving as a conductive film in a predetermined pattern on the surface of a ceramic green sheet obtained by adding and mixing an appropriate organic solvent to the ceramic material powder. A plurality of sheets are laminated and press-molded, and then fired at a high temperature.

  The base substrate and the lid substrate connecting electrode 6 are a pair of conductive films deposited on the base substrate 7 and the lid substrate 8, and are formed using a metal material such as silver, copper, or tungsten. In addition, nickel plating or gold plating is applied to the surface as necessary. In addition to the base substrate and the lid substrate connecting electrode 6, a ground electrode is formed on the base substrate 7 and the lid substrate 8 with the same metal material.

  The conductive adhesive 10 is made of, for example, a polyimide resin, an epoxy resin, or a silicone resin as a main component, and a conductive material such as Ag is uniformly dispersed. The conductive adhesive 10 mechanically bonds the base substrate 7 and the lid substrate 8 to the fixed end portion of the crystal resonator element 1, and at the same time, the base substrate 7, the base substrate of the lid substrate 8, and the electrode 6 for connecting the lid substrate. And the element connection electrode 9 of the crystal resonator element 1 are electrically connected to each other.

  Between the base substrate 7 and the lid substrate 8 described above, a plurality of conductive bonding materials 12 that electrically connect the element connection electrodes 9 and the external terminal electrodes 11 of the crystal resonator element 1 are electrically conductive. An annular sealing member 13 is interposed on the outer side of the conductive bonding material 12, and the sealing member 13 is a space provided between the base substrate 7 and the lid substrate 8, specifically, a lid substrate. 8 is hermetically sealed by surrounding the storage area of the crystal resonator element 1 surrounded by the lower surface of 8 and the upper surface of the base substrate.

  Further, as the conductive bonding material 12 and the sealing member 13 described above, for example, a brazing material made of a metal such as Au, Au—Sn alloy, or solder is preferably used, and the sealing member 13 includes the base substrate 7 and the lid substrate. 8 is electrically connected to the external terminal electrode 21 of the base substrate 8 through the wiring conductor 14 and the like.

The mounting structure of the above-described quartz resonator element can be obtained by the following manufacturing method.
First, the base substrate 7 and the lid substrate 8 having the crystal resonator element 1 and the base substrate and the lid substrate connecting electrode 6 are prepared. Next, a conductive resin paste to be the conductive adhesive 10 is applied on the base substrate and the lid substrate connecting electrode 6. For the conductive adhesive 10, for example, a conductive resin paste mainly composed of a polyimide resin and in which Ag particles are homogeneously dispersed is used. The base substrate 7 and the lid substrate 8 are attached to the base substrate 7 and the lid substrate 8. It is applied on the electrode 6. Next, the crystal resonator element 1 is placed on the base substrate 7 and the lid substrate 8 so that the element connection electrode 9 of the crystal resonator element 1 is positioned on the conductive resin paste that becomes the conductive adhesive 10. . Then, with the crystal resonator element 1 placed, the conductive resin paste is completely heat-cured by a heat treatment at about 200 ° C. As a result, the conductive paste becomes the conductive adhesive 10, and the crystal resonator element 1 is mounted on the base substrate 7 and the lid substrate 8 so as to be held only on one side.

  Next, as a method of manufacturing the crystal resonator element 1 as described above, a rectangular shape is first processed to a thickness that excites a desired frequency in the thickness-shear vibration mode from both main surface sides of a flat plate-shaped crystal wafer. A plurality of excitation electrode regions 2 are formed by photolithography and etching to form a stepped portion 3 having a rectangular outer peripheral shape having a thickness of the quartz wafer around the excitation electrode region 2 and individual excitation electrodes. Among the stepped portions 3 formed on the outer peripheral portion of the region 2, the base substrate and the lid substrate connecting electrode 6 are formed, and a plurality of rows are arranged in a matrix at a position where the abandoned region portion formed integrally with the stepped portion 3 is formed. Form.

  Next, the excitation electrode 4 is formed on the front and back main surfaces of the individual excitation electrode regions 2 of the crystal wafer subjected to the outer shape processing as described above, and the step portion 3 formed from the excitation electrode 4 to the outer peripheral portion of the excitation electrode region 2. The lead electrode 5 extending to one edge of the outer periphery, the base substrate electrically connected to the lead electrode 5 and the electrode 6 for connecting the lid substrate are formed so as to face both main surfaces of the crystal wafer. An interelectrode connecting electrode 8 for electrically connecting the base substrate and the lid substrate connecting electrodes 6 is formed by vapor deposition. The form after forming the various electrodes in this way is shown in FIGS.

  Next, the crystal wafer is cut by a predetermined cutting line so as to form a predetermined region around the excitation electrode region 2 and a step portion having a thickness of the crystal wafer, so that a plurality of crystal resonator elements each processed individually 1 is formed.

  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.

  In the embodiment described above, as shown in FIG. 5, the connection accuracy and the connection strength can be improved by forming the element connection electrode on the entire surface of the stepped portion.

  Moreover, in embodiment mentioned above, as shown in FIG. 6, it is connected to the one level | step-difference part with the conductive adhesive 10, and it can improve fixed strength with an insulating adhesive to the other level | step difference part. It becomes possible.

  Further, in the above-described embodiment, as shown in FIG. 7, since the step portions of the crystal resonator element are formed at both ends, it is possible to stably connect in terms of strength of the crystal resonator element.

  Furthermore, in the above-described embodiment, when a shield layer is deposited and formed from the upper surface to the side surface of the lid substrate 8, and a part of the shield layer is deposited on the sealing member 13, noise from the outside is reduced. It is possible to shield better, and it is possible to maintain high operation reliability of the crystal resonator.

  Furthermore, in the above-described embodiments, the surface-mount type crystal resonator using the crystal resonator element has been described as an example, but other piezoelectric resonator elements such as a surface acoustic wave (SAW) filter are used instead. Even in this case, the present invention is applicable.

  Furthermore, in the embodiment described above, the sealing member 13 is interposed outside the conductive bonding material 12, but the present invention can be applied even when the conductive bonding material 12 is provided outside the sealing member 13. is there.

FIG. 1 is an exploded perspective view of a crystal resonator according to the present invention. FIG. 2 is a cross-sectional view of the crystal resonator shown in FIG. FIG. 3 is an external perspective view illustrating a form in which individual crystal resonator elements are formed on a crystal wafer when the crystal resonator element is manufactured according to the present invention. FIG. 4 is an external perspective view illustrating a form in which individual crystal resonator elements are formed on a crystal wafer when manufacturing the crystal resonator elements according to the present invention. FIG. 5 is an exploded perspective view showing another embodiment of the crystal resonator of the present invention. FIG. 6 is an exploded perspective view showing another embodiment of the crystal resonator of the present invention. FIG. 7 is an exploded perspective view showing another embodiment of the crystal resonator of the present invention. FIG. 8 is a cross-sectional view of a conventional crystal resonator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Quartz crystal vibration element 2 ... Excitation electrode area | region 3 ... Level difference part 4 ... Excitation electrode 5 ... Extraction electrode 6 ... Electrode for base substrate and lid substrate connection 7 ... Base substrate DESCRIPTION OF SYMBOLS 8 ... Lid board | substrate 9 ... Element connection electrode 10 ... Conductive adhesive 11 ... External terminal electrode 12 ... Conductive joining material 13 ... Sealing member 14 ... Wiring conductor

Claims (2)

A crystal resonator comprising a crystal resonator element, a base substrate for mounting the crystal resonator element, and a lid substrate for sealing,
A step portion is formed in an outer peripheral portion of the crystal resonator element, and an extraction electrode is formed in the step portion, and the step portion, the base substrate, and the lid substrate are sandwiched and fixed. A crystal resonator. The crystal resonator according to claim 1, wherein element connection electrodes formed on the crystal resonator element are formed on both main surfaces.

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