JP2006074272A - Crystal vibrating plate and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that the outer shape of a crystal vibrating plate is formed by cutting work in a conventional high frequency crystal resonator, a metallic film or the like cannot be formed on the surface of a side on which a container connecting electrode is formed on a reinforcing part constituting the crystal vibrating plate, so that it is difficult to make container connecting electrodes formed on front and rear main surfaces of the reinforcing part conductive. <P>SOLUTION: In the crystal vibrating plate comprising a rectangular piezoelectric oscillation area oscillated at a required frequency and a reinforcing part formed thicker than the piezoelectric oscillation area so as to surround the outer periphery of the piezoelectric oscillation area and having a rectangular outer peripheral shape integrally with the piezoelectric oscillation area, grooves penetrated into the front and rear surfaces of the reinforcing part on the outer peripheral side face of the reinforcing part on which container connecting electrodes are formed, and inter-electrode connecting electrodes for electrically connecting the container connecting electrodes formed on the front and rear surfaces of the reinforcing part are formed on surfaces of the grooves. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a quartz crystal plate used for a quartz resonator and a manufacturing method thereof, and more particularly, to a quartz plate and a manufacturing method thereof that undergo thickness shear vibration at a high frequency of 100 MHz or higher.

Conventionally, a crystal resonator is used as a reference signal generation source in an electronic device such as a portable communication device, and various electrodes are provided on the main surface of the crystal base plate in an airtight container of the crystal resonator. A formed crystal diaphragm is used.

  Among such conventional quartz diaphragms, in particular, as a quartz diaphragm that excites vibrations of several hundred MHz or more as a thickness-slip fundamental wave vibration, a piezoelectric vibration region portion that excites at a desired fundamental frequency, and its piezoelectric vibration region A reinforcing portion that is integral with the piezoelectric vibration region portion and is thicker than the piezoelectric vibration region portion, and a multilayer that uses gold, silver, or an alloy at predetermined locations on the surface of the piezoelectric vibration region portion and the reinforcing portion. Various devices having various structures have been devised.

  More specifically, a rectangular piezoelectric vibration region that is excited at a desired frequency is formed. A reinforcing portion having a rectangular outer peripheral shape which is formed integrally with the piezoelectric vibration region portion and is thicker than the piezoelectric vibration region portion is formed around the periphery. In the case of the quartz diaphragm disclosed in the prior art document to be described later, the thickness difference between the piezoelectric vibration region portion and the reinforcement portion is configured only on one main surface side, and the piezoelectric vibration region portion and the reinforcement portion on the other main surface side. Discloses a quartz base plate having a flat structure with no step between them.

In the AT-cut quartz resonator, the vibration mode is thickness shear vibration, and the frequency thereof is inversely proportional to the thickness of the piezoelectric vibration region portion. Therefore, in order to increase the frequency, it is necessary to reduce the thickness of the piezoelectric vibration region portion. At present, when an AT-cut quartz base plate is simply formed in a flat plate shape, the thickness is about 17 μm (about 100 MHz for fundamental wave vibration), and the piezoelectric vibration region portion as shown in FIG. In the case of a quartz crystal resonator in which a reinforcing part thicker than the thickness of the piezoelectric vibration area is integrally formed around the piezoelectric element, a piezoelectric vibration area having a thickness of about 5 μm (about 350 MHz for fundamental vibration) is created. Has been.

  In the crystal base plate processed into such a shape, an excitation electrode on the front and back main surfaces of the piezoelectric vibration region portion, an extraction electrode drawn from the excitation electrode through the reinforcement portion, and an outer periphery of the reinforcement portion A quartz crystal diaphragm is formed by forming a container connection electrode electrically connected to the extraction electrode formed in the vicinity of the front and back edge portions on one side.

  In addition, as a method of manufacturing such a crystal diaphragm, a rectangular shape is formed at a predetermined position on one main surface of a flat plate-shaped crystal wafer, and a plurality of concave recesses are formed in a matrix by photolithography and etching. Align and form. The thickness of the bottom of the recess is etched to a thickness at which a desired frequency vibrates to form a piezoelectric vibration region. The piezoelectric vibration region portion is formed at a position where a reinforcing portion having a thickness of the quartz wafer is integrally formed around the piezoelectric vibration region portion so as to support and reinforce the piezoelectric vibration region portion.

  On the front and back main surfaces of the individual piezoelectric vibration area portions, circular excitation electrodes are formed so as to face each other, and the extraction electrodes extend from the excitation electrodes to the front and back surfaces of the reinforcing portions around the piezoelectric vibration area portions. The lead electrode is formed so as to extend to two container connection electrodes on the front and back sides formed on one edge of each reinforcing part and to be electrically connected to the container connection electrode.

  Thereafter, a crystal wafer formed by arranging and arranging a plurality of piezoelectric vibration region portions and reinforcing portions formed on the front and back main surfaces of the excitation electrode, the extraction electrode, and the container connecting electrode on the front and back main surfaces, and a cutting line defined for each reinforcing portion A plurality of crystal diaphragms cut into pieces and processed into pieces are formed.

  In addition, the following prior art documents are well-known about such a crystal diaphragm and its manufacturing method.

Japanese Patent Laid-Open No. 2004-40693 JP 2001-257560 A

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

  However, in the above-described conventional quartz diaphragm, the outer shape of the quartz diaphragm is formed by cutting, so that the container connection electrode is formed on the side surface of the reinforcing portion constituting the quartz diaphragm. Since a metal film or the like cannot be formed, it is difficult to conduct between the container connection electrodes formed on the front and back main surfaces of the reinforcing portion.

  In such a container connection electrode, it is necessary to make electrical connection as a method for establishing electrical continuity with the container-side element connection electrode pad when the crystal diaphragm is mounted inside the crystal resonator container. A large amount of conductive adhesive may be applied to the front and back container connection electrodes, the side surfaces of the crystal diaphragm and the element connection electrode pads to conduct the container connection electrodes and the element connection electrode pads. Due to the miniaturization of the child, the space for mounting the quartz diaphragm is remarkably narrowed, so it has become difficult to apply a large amount of conductive adhesive.

  In some cases, conduction means by wire bonding may be used, but the element-side electrode pads on the container side must be provided outside the outer shape of the crystal diaphragm, which hinders miniaturization of the container. In addition, the man-hours increase and there are many problems.

  Furthermore, a through hole is formed in the container connection electrode, the container connection electrodes on the front and back sides are electrically connected, and the container connection electrode and the element connection electrode pad formed on the container side main surface of the crystal diaphragm Although a means for fixing and conducting the material with a conductive adhesive has been devised, the size of the container connecting electrode formed on the reinforcing portion of the quartz diaphragm is significantly reduced as the quartz diaphragm is downsized. It is difficult to secure a space for forming a hole. Moreover, there is a concern that the strength of the reinforcing portion is reduced by forming the through hole in the reinforcing portion.

  In order to solve the above-mentioned problems, a quartz crystal diaphragm according to the present invention has a rectangular piezoelectric vibration region portion that excites a desired frequency, and is thicker than the thickness of the piezoelectric vibration region portion so as to surround the outer periphery of the piezoelectric vibration region portion. A reinforcing portion having a rectangular outer peripheral shape is integrally formed with the piezoelectric vibration region portion. Further, an excitation electrode is drawn on the front and back main surfaces of the piezoelectric vibration region portion, and is pulled out from the excitation electrode through the reinforcement portion. The container connection electrode is formed in a quartz crystal diaphragm including an extraction electrode and an extraction electrode formed in the vicinity of the front and back edges of one side of the outer periphery of the reinforcing portion. A groove that connects the front and back of the reinforcing portion is formed on the outer peripheral side surface of the reinforcing portion, and an inter-electrode connection that electrically connects the container connecting electrodes formed on the front and back surfaces of the reinforcing portion on the surface of the groove. An electrode is formed It is a crystal vibration plate.

In addition, as a method for manufacturing the above-described quartz crystal plate, a rectangular crystal wafer having a thickness processed from one main surface side of the quartz wafer up to a thickness that excites a desired frequency in a thickness-shear vibration mode on a flat-plate shaped quartz wafer. A plurality of piezoelectric vibration region portions having a shape are arranged in a matrix at positions where a reinforcing portion having a rectangular outer peripheral shape with a thickness of a quartz wafer is formed around the piezoelectric vibration region portion by photolithography and etching. A plurality of alignments are formed, and one side of the outer periphery of the reinforcing part is provided via an excitation electrode on the front and back main surfaces of the piezoelectric vibration area part and a reinforcement part formed around the piezoelectric vibration area part from the excitation electrode. Forming an extraction electrode extending to the edge, and a container connection electrode electrically connected to the extraction electrode in the vicinity of the front and back edges of one side of the outer periphery of the reinforcing portion extending from the extraction electrode, at a predetermined position Cut the reinforcement with In the method of forming the individual crystal plate,
Of the reinforcing portions formed around each piezoelectric vibration region portion, the first side of the reinforcing portion that forms the container connection electrode and the second side of the reinforcing portion of another quartz crystal plate opposite to the first side Forming an abandonment area formed integrally with the reinforcing part between
Forming a through-hole penetrating the front and back main surfaces of the crystal wafer so as to straddle the region for forming the container connection electrode at the first edge of each reinforcing portion and the abandoned region in contact with the first side; A step of forming the container connection electrode that is electrically connected to the inner surface of the reinforcement portion side surface of the through hole and the region for forming the container connection electrode on the front and back surfaces of the reinforcement portion;
Forming a plurality of crystal diaphragms obtained by cutting a crystal wafer into a predetermined region and cutting into individual pieces so as to form a reinforcing portion having a predetermined region and a thickness of the crystal wafer around the vibration region. A method for manufacturing a quartz crystal diaphragm.

  According to the crystal diaphragm of the present invention described above, a groove reaching the container connection electrode formed on the front and back of the reinforcement portion is formed on the side surface of the reinforcement portion where the container connection electrode is formed, and the groove is formed on the inner surface of the groove. By forming the electrode connection electrode that is electrically connected to each container connection electrode, the container connection electrode on the front and back main surfaces of the reinforcement part can be electrically connected without reducing the strength of the reinforcement part, and By changing the shape and size of the groove, it is possible to cope with the narrowing of the container connection electrode due to the miniaturization of the crystal diaphragm. Further, even when the container connection electrode and the element connection electrode pad are fixed and conducted, the amount of the conductive adhesive applied to the container connection electrode formed on the container side main surface of the quartz diaphragm reinforcing portion, Since it can be limited to the amount used only for the fixed continuity between the electrode for connecting an element that can be formed at a position facing the container connecting electrode, it is effective in miniaturizing a crystal resonator using a crystal diaphragm.

  Furthermore, according to the method for manufacturing a quartz crystal diaphragm of the present invention, a through hole is formed on the cutting line between the reinforcing portion and the surplus region, and the through hole is cut in the longitudinal direction so that the reinforcing portion and the surrogate are cut. A groove can be easily formed on the side surface of the region. In addition, the size of the groove on the reinforcement part side can be arbitrarily formed by changing the ratio of the opening of the through hole between the reinforcement part and the removal area around the cutting line, so it is easy to change the shape of the quartz diaphragm It can correspond to.

  Therefore, by using the crystal diaphragm and the manufacturing method thereof according to the present invention, it is possible to cope with the downsizing of the crystal diaphragm and to efficiently manufacture the crystal diaphragm.

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 a perspective view of a quartz crystal diaphragm according to the present invention. FIG. 2 is a structural diagram illustrating a mounting form when the crystal diaphragm shown in FIG. 1 is mounted on a crystal resonator container. FIG. 3 is a perspective view illustrating a form in a quartz wafer state when the quartz diaphragm is manufactured in the present invention. FIG. 4 is a partially enlarged perspective view showing a part of the quartz wafer shown in FIG. 3 in an enlarged manner.
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.

  The crystal diaphragm 10 shown in FIGS. 1 and 2 is generally formed with a rectangular piezoelectric vibration region portion 11 that is excited at a desired frequency. A quartz base plate 13 is formed by forming a reinforcing portion 12 which is integrally formed with the piezoelectric vibration region portion 11 and is thicker than the piezoelectric vibration region portion 11 and has a rectangular outer peripheral shape. In FIG. 1, the thickness difference between the piezoelectric vibration region portion 11 and the reinforcement portion 12 is configured only on one main surface side of the quartz base plate 13, and the piezoelectric vibration region portion 11 and the reinforcement portion 12 are on the other main surface side. It has a flat plate structure with no step between them. In the quartz base plate 13 disclosed in FIG. 1, only the first reinforcing portion 12 a formed in one side direction of the piezoelectric vibration region portion 11 among the reinforcing portions 12 formed around the rectangular piezoelectric vibration region portion 11. Although the principal surface area is larger than the reinforcing portion formed on the other side, this size is arbitrarily determined within a range that does not affect the excitation mode of the piezoelectric vibration region portion 11.

  The crystal base plate 13 of FIG. 1 is cut out from a crystal crystal by so-called AT cut and processed into a flat plate, and the vibration mode of the piezoelectric vibration region portion 11 is thickness shear vibration. Since the frequency is inversely proportional to the thickness of the piezoelectric vibration region portion 11, it is necessary to reduce the thickness of the piezoelectric vibration region portion 11 in order to increase the frequency. In the case of the quartz base plate 13 in which a reinforcing portion thicker than the thickness of the piezoelectric vibration area is integrally formed around the piezoelectric vibration area as shown in FIG. 1, the thickness of the piezoelectric vibration area 11 is about 5 μm (basic Wave vibration can be created up to about 350 MHz.

On the crystal base plate 13 processed in such a shape, a circular excitation electrode 14 on the front and back main surfaces of the piezoelectric vibration region portion 10, and an extraction electrode 15 drawn from the excitation electrode 14 via a reinforcement portion, The crystal diaphragm 10 is formed by forming the container connection electrode 16 electrically connected to the extraction electrode 15 formed in the vicinity of the front and back edge portions of one side (first reinforcement portion 12a) of the outer periphery of the reinforcement portion 12. Is forming.

Further, on the side surface of the crystal base plate 13 on which the container connecting electrode 16 is formed, a groove 17 extending from the front main surface to the back main surface of the crystal base plate faces the main surfaces of the crystal base plate 13. The container connection electrodes 16 are formed in such a manner as to be connected to each other, and the container connection electrodes 16 formed on the inner surface of the groove 17 are electrically connected to each other. For this purpose, an interelectrode connection electrode 18 is formed.

  The crystal diaphragm 10 having such a shape is mounted inside a container 21 constituting the crystal resonator 20 as shown in FIG. That is, the crystal diaphragm 10 has a configuration in which a main surface having a step between the piezoelectric vibration region portion 11 and the reinforcing portion 12 is directed to the inner bottom surface of the container 21, and on the inner bottom surface of the container 21. The element connection electrode pad 22 formed at a position corresponding to the container connection electrode 16 formed in the above is fixedly conducted through a conductive adhesive 23. At this time, the conductive adhesive 23 is applied only in such an amount that the container connection electrode 16 formed on the container-side main surface of the quartz crystal plate 10 and the element connection electrode pad 22 can be firmly connected. Since the portion enters the groove 17, the fixing strength of the crystal diaphragm 10 can be improved. Further, when a protrusion is formed on the surface of the element connection electrode pad 22, a groove formed in the crystal diaphragm 10 is fitted into the protrusion, thereby enabling alignment when the crystal diaphragm 10 is mounted.

  Next, as a method of manufacturing the above-described quartz crystal plate, first, a rectangular shape in which a thickness is processed from one main surface side of the flat crystal wafer 30 to a thickness for exciting a desired frequency in the thickness-shear vibration mode. A plurality of piezoelectric vibration region portions 11 are formed by a photolithography method and etching to form a reinforcement portion 12 having a rectangular outer peripheral shape having a thickness of the quartz wafer 30 around the piezoelectric vibration region portion 11, and Of the reinforcing portions 12 formed around the individual piezoelectric vibration region portions 11, the first side 31 of the first reinforcing portion 12 a that forms the container connection electrode 16 and another crystal vibration facing the first side 31. Between the second side 32 of the reinforcing part 12 of the plate, a plurality of arrayed areas are formed in a matrix at a position where the abandoned area part 33 formed integrally with the reinforcing part 12 is formed.

  In addition to the formation of the piezoelectric vibration region portion 11, the region for forming the container connection electrode 16 at the edge of the first side 31 of each of the first reinforcing portions 12 a and the abandoned region portion in contact with the first side 31. A through-hole 34 penetrating the front and back main surfaces of the crystal wafer 30 is formed so as to straddle 33.

  Next, the circular excitation electrode 14 is formed on the front and back main surfaces of the individual piezoelectric vibration region portions 11 of the crystal wafer 30 subjected to the outer shape processing as described above, and the periphery of the piezoelectric vibration region portion 11 from the excitation electrode 14. The extraction electrode 15 extended to one edge of the outer periphery of the reinforcement portion 12 through the reinforcement portion 12 formed on the first portion, and the first side of the outer periphery of the first reinforcement portion 12a extended with the extraction electrode In the vicinity of the front and back edge portions of 31, the container connection electrode 16 electrically connected to the extraction electrode 15 and the inner surface of the through hole 34 on the first reinforcing portion 12 a side are formed so as to face both main surfaces of the crystal wafer 30. Interelectrode connection electrodes 18 for electrically connecting the container connection electrodes 16 to each other are formed by vapor deposition. The form after forming the various electrodes in this way is shown in FIGS.

  Next, the crystal wafer 30 is cut along a predetermined cutting line A so as to form a predetermined region and a thickness-reinforcing portion 12 around the piezoelectric vibration region portion 11, thereby forming one through hole 34. The separation region portion 33 where the portion is formed is separated, and a plurality of crystal diaphragms 10 each processed by a single piece are formed.

  In the present embodiment, the shape of the opening of the through hole 34 is rectangular, but it may be circular or polygonal. Further, in the present embodiment, the formation positions of the through holes 34 are equally applied to the separation region portion 33 and the first reinforcement portion 12a on the cutting line separating the separation region portion 33 and the first reinforcement portion 12a. Although formed, depending on the shape of the opening of the through-hole 34, it may be formed at a position biased to either.

FIG. 1 is a perspective view of a crystal diaphragm according to the present invention. FIG. 2 is a schematic perspective view illustrating a mounting form when the crystal diaphragm shown in FIG. 1 is mounted on a crystal resonator container. FIG. 3 is a perspective view illustrating a form in which individual crystal diaphragms are formed on a quartz wafer when the quartz diaphragm is manufactured according to the present invention. FIG. 4 is a partially enlarged perspective view showing a part of the crystal wafer shown in FIG. 3 in an enlarged manner.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Crystal diaphragm 11 ... Piezoelectric vibration area | region 12 ... Reinforcement part 12a .... 1st reinforcement part 13 ... Crystal base plate 14 ... Excitation electrode 15 ... Extraction electrode 16 ... ..Electrode for container connection 17... Groove 18... Electrode for interelectrode connection 30... Crystal wafer 33.

Claims (2)

  A rectangular piezoelectric vibration region that excites a desired frequency, and a reinforcing portion that is thicker than the piezoelectric vibration region and has a rectangular outer shape so as to surround the outer periphery of the piezoelectric vibration region. And an excitation electrode on the front and back main surfaces of the piezoelectric vibration region portion, an extraction electrode drawn from the excitation electrode through the reinforcement portion, and an outer periphery of the reinforcement portion. In a crystal diaphragm comprising a container connecting electrode electrically connected to the lead electrode formed in the vicinity of the front and back edge portions on one side, the outer peripheral edge portion of the reinforcing portion on which the container connecting electrode is formed A groove that connects the front and back of the reinforcing portion is formed, and an electrode for interelectrode connection that electrically connects the container connecting electrodes formed on the front and back surfaces of the reinforcing portion is formed on the surface of the groove. A quartz crystal diaphragm characterized by comprising: A plurality of rectangular piezoelectric vibration region portions having a thickness processed from one main surface side of the quartz wafer up to a thickness for exciting a desired frequency in a thickness-shear vibration mode on a flat plate-shaped quartz wafer, a photolithography method and By etching, a plurality of matrix-shaped reinforcement portions are formed around the piezoelectric vibration region portion at positions where the outer peripheral shape having a thickness of the quartz wafer is rectangular, and the front and back surfaces of the piezoelectric vibration region portion are formed. An excitation electrode on the main surface, and an extraction electrode extending from the excitation electrode to one edge of the outer periphery of the reinforcement portion via the reinforcement portion formed around the piezoelectric vibration region portion; Forming a container connection electrode electrically connected to the extraction electrode in the vicinity of the front and back edges of one side of the outer periphery of the reinforcement portion extended by the extraction electrode, and cutting the reinforcement portion at a predetermined position Individual crystal diaphragms In the manufacturing method,
Of the reinforcing portions formed around the individual piezoelectric vibration region portions, the first side of the reinforcing portion that forms the container connection electrode and the first side of the reinforcing portion of another quartz crystal plate facing the first side. Forming an abandonment region formed integrally with the reinforcing portion between the two sides;
A through-hole penetrating the front and back main surfaces of the crystal wafer so as to straddle the region for forming the container connection electrode at the first edge of each reinforcing portion and the abandoned region in contact with the first side Forming, and
A step of forming the container connection electrode that is electrically connected to the region on the front and rear surfaces of the reinforcement portion where the container connection electrode is formed and the reinforcement portion side inner surface of the through hole;
Forming a plurality of crystal diaphragms by cutting the crystal wafer into pieces having a predetermined outer size so as to form a predetermined region and a reinforcing portion having a thickness of the crystal wafer around the vibration region; A method of manufacturing a quartz crystal diaphragm, comprising:

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