JP2007081697A - Piezoelectric oscillation device and method of manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow the frequency of a piezoelectric oscillating piece to be a preset one even if the frequency of it fluctuates due to jointing of a cap to a base. <P>SOLUTION: An insulating separation board 4 that separates substrate regions 28 and 38 related to frequency adjustment of quartz resonators 2 and 3, is interposed between the quartz resonators 2 and 3 that are jointed and held on a base 11 in an internal space 14 sealed up airtight in a package 13. On both main surfaces of the separation board 4, frequency changing parts 81 and 82 for changing frequency of the quartz resonators 2 and 3 are so provided as to face the substrate regions 28 and 38 related to frequency adjustment of the quartz resonators 2 and 3. The frequency changing parts 81 and 82 performs fine adjustment of frequency of the quartz resonators 2 and 3 within the airtight internal space 14 by electrically heating them for evaporation, and allowing the evaporated frequency changing members 81 and 82 to be deposited on the quarts resonators 2 and 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a piezoelectric vibration device and a manufacturing method thereof.

  Currently, examples of piezoelectric vibrating devices include tuning fork type crystal resonators (hereinafter referred to as crystal resonators). In this type of piezoelectric vibration device, a package which is a casing is composed of a base and a cap, and the inside of the casing is hermetically sealed. Further, inside the casing, a piezoelectric vibrating piece (quartz crystal vibrating piece) is bonded to an electrode pad on the base via a conductive adhesive.

  In this quartz crystal resonator element, the substrate is composed of a base portion and two leg portions protruding from the base portion, and excitation electrodes configured with different potentials are formed on the leg portions. In addition, an extraction electrode for electrically connecting the excitation electrode to the electrode pad is formed on the base. This extraction electrode is formed so as to be drawn from the excitation electrode (see, for example, Patent Document 1).

  Patent Document 1 described above discloses a crystal resonator that is manufactured by disposing a crystal resonator element on a base and then heat-sealing the internal space by heat-bonding the opening of the base with a cap.

In this manufacturing process, after the quartz crystal vibrating piece is arranged on the base, the final oscillation frequency adjustment (hereinafter referred to as final frequency adjustment) of the quartz crystal vibrating piece is performed. Then, after adjusting the final frequency of the crystal vibrating piece, the opening of the base is heat-joined with a cap to form a package as a housing, and the crystal vibrating piece is hermetically sealed in the internal space of the package. That is, the final frequency adjustment of the crystal vibrating piece is performed before the base is joined with the cap and the crystal vibrating piece is hermetically sealed in the internal space.
JP 2004-200910 A

  By the way, when measuring the oscillation frequency (hereinafter referred to as frequency) of the crystal resonator element that has been subjected to final frequency adjustment and the frequency of the crystal resonator element hermetically sealed in the internal space of the package by the base and the cap, The frequency of the resonator element is fluctuating. Specifically, the frequency adjustment of the quartz crystal vibrating piece hermetically sealed in the internal space has a lower or higher value than the frequency of the quartz crystal vibrating piece adjusted by the final frequency adjustment. This is because the base and the cap are heated and bonded when the base and the cap are bonded, so that the frequency of the crystal vibrating piece in the internal space with respect to the frequency of the crystal vibrating piece that has been subjected to the final frequency adjustment. Is fluctuating.

  Therefore, in order to solve the above-described problems, the present invention provides a preset frequency (described above) even when the frequency of the piezoelectric vibrating piece fluctuates due to the joining of the cap to the base. It is an object of the present invention to provide a piezoelectric vibration device having a frequency at the time of final frequency adjustment in the conventional example and a manufacturing method thereof.

  In order to achieve the above object, a piezoelectric vibration device according to the present invention includes a cap joined to a base to form a package, an internal space is formed in the package, and a piezoelectric is formed on the base in the internal space. In the piezoelectric vibration device in which the vibration piece is held, a frequency variable member for changing the frequency of the piezoelectric vibration piece is provided in the internal space, and the frequency variable member is electrically heated so that the piezoelectric vibration piece is The frequency is variable.

  According to the present invention, a frequency variable member for varying the frequency of the piezoelectric vibrating piece is provided in the internal space, and the frequency variable member is electrically heated to vary the frequency of the piezoelectric vibrating piece. Therefore, even when the frequency of the piezoelectric vibrating piece varies due to the joining of the cap to the base, the frequency of the piezoelectric vibrating piece can be set to a preset frequency. Specifically, even when the frequency of the piezoelectric vibrating piece fluctuates due to the joining of the cap to the base, the fluctuating frequency of the piezoelectric vibrating piece can be corrected to the frequency at the time of final frequency adjustment. It becomes possible. That is, it is possible to correct the fluctuating frequency by finely adjusting the frequency of the piezoelectric vibrating piece in the internal space. Therefore, fine adjustment of the frequency of the piezoelectric vibrating piece is performed in the internal space even when the piezoelectric vibrating piece is hermetically sealed from the base and the cap, that is, after the internal space is formed. The frequency can be corrected. In particular, when manufacturing the piezoelectric vibration device, it has undergone a thermal history such as an annealing process, a sealing process, a reflow process, etc., and the piezoelectric vibration piece adjusted in a milling process or a partial process through this thermal history. Although the frequency (oscillation frequency) varies, according to the present invention, since the frequency of the piezoelectric vibrating piece is varied by the frequency variable member after passing through a thermal history, the piezoelectric vibrating piece that has fluctuated through the thermal history described above can be obtained. It is possible to finely adjust the frequency to suppress a frequency deviation defect.

  The said structure WHEREIN: The said package may consist of a non-light transmissive member.

  In this case, since the package is made of a non-light transmissive member, the frequency of the frequency variable member cannot be adjusted by a laser or the like from the outside of the package. However, according to the present invention, since the frequency variable member is electrically heated in the internal space and the frequency of the piezoelectric vibrating piece is variable, the internal space is formed even after the internal space is formed. It is possible to finely adjust the frequency of the piezoelectric vibrating piece in the space.

  In the above-described configuration, an electrode is formed on the piezoelectric vibrating piece, and a plurality of base electrodes are formed on the base that are drawn from an inner surface facing the inner space of the base to an outer surface that is an outer peripheral surface of the base, The electrode formed on the piezoelectric vibrating piece may be connected to a part of the plurality of base electrodes, and the frequency variable member may be connected to the other part of the plurality of base electrodes.

  In this case, the electrode is formed on the piezoelectric vibrating piece, the plurality of base electrodes are formed on the base, and the electrode formed on the piezoelectric vibrating piece is connected to a part of the plurality of base electrodes. Since the frequency variable member is connected to the other part of the plurality of base electrodes, an external power source is connected to the base electrode to which the frequency variable member is connected, and the voltage is supplied from the external power source, whereby the frequency The variable member is heated, the frequency variable member is evaporated by this heating, the evaporated frequency variable member adheres to the piezoelectric vibrating piece, and the frequency of the piezoelectric vibrating piece is lowered. Further, an existing base electrode can be used without newly designing a base electrode dedicated to the frequency variable member, and an existing base can be used. Further, the piezoelectric vibrating piece is hermetically sealed from the base and the cap, that is, even after the internal space is formed, the frequency of the piezoelectric vibrating piece is finely adjusted in the internal space. This is preferable for correcting the frequency. Here, the other part of the plurality of base electrodes does not mean all the remaining bases other than a part of the plurality of base electrodes, but a remaining part other than a part of the plurality of base electrodes. It may be. That is, the other portions of the plurality of base electrodes may be used not only as electrodes for electrically heating the frequency variable member, but also as the ground electrodes and dummy electrodes.

  In the above configuration, an electromagnetic induction heating member for electromagnetically heating the frequency variable member may be provided in the internal space.

  In this case, since the electromagnetic induction heating member for electromagnetically heating the frequency variable member is provided in the internal space, a current is generated in the frequency variable member by electromagnetic induction, and the current is generated by the current. The frequency variable member is heated, and the frequency variable member is evaporated by the heating, and the evaporated frequency variable member adheres to the piezoelectric vibrating piece to change the frequency of the piezoelectric vibrating piece. Therefore, fine adjustment of the frequency of the piezoelectric vibrating piece is performed in the internal space even when the piezoelectric vibrating piece is hermetically sealed from the base and the cap, that is, after the internal space is formed. This is preferable for correcting the frequency. In addition, after fine adjustment of the frequency of the piezoelectric vibrating piece is performed after the internal space is formed, it is possible to eliminate a frequency variation element that causes the piezoelectric vibrating piece to be opened to the atmosphere.

  In the above configuration, the frequency variable member may be a low melting point material.

  In this case, since the frequency variable member is made of a material having a low melting point, it is preferable to heat only the frequency variable member without generating heat to other constituent members.

  The said structure WHEREIN: The getter material which reduces the pressure in the said internal space may be provided in the said internal space.

  In this case, since the getter material for reducing the pressure in the internal space (hereinafter referred to as internal pressure) is provided in the internal space, the internal pressure can be reduced in the internal space by the getter material. Therefore, it becomes possible to prevent the series resonance resistance value of the piezoelectric vibration device from increasing. In particular, it is preferable for lowering the internal pressure after the piezoelectric vibrating piece is hermetically sealed from the base and the cap, that is, after forming the internal space.

  The said structure WHEREIN: Between the said getter material and the said piezoelectric vibrating piece, the shielding board which shields the said getter material and the said piezoelectric vibrating piece may be provided.

  In this case, since a shielding plate that shields the getter material and the piezoelectric vibrating piece is provided between the getter material and the piezoelectric vibrating piece, when the getter material is evaporated, It is possible to prevent the getter material collecting gas molecules from adhering to the piezoelectric vibrating piece.

  The said structure WHEREIN: The said getter material may be distribute | arranged to the position isolated from the said piezoelectric vibrating piece.

  In this case, since the getter material is disposed at a position isolated from the piezoelectric vibrating piece, the getter material that collects gas molecules in the piezoelectric vibrating piece in the internal space when the getter material is evaporated. Can be prevented from adhering. Further, when a tuning fork type piezoelectric vibrating piece is used as the piezoelectric vibrating piece, it is possible to improve the series resonance resistance value with almost no frequency fluctuation.

  In order to achieve the above object, a method of manufacturing a piezoelectric vibration device according to the present invention is the above-described method of manufacturing a piezoelectric vibration device, wherein the cap is joined to the base to form the internal space, After finely adjusting the frequency of the piezoelectric vibrating piece in the internal space by electrically heating the frequency variable member, and after forming the internal space by joining the cap to the base, A pressure reduction step of reducing the pressure of the internal space in the internal space by a getter material, wherein the frequency fine adjustment step and the pressure reduction step are alternately performed.

  According to the present invention, since the frequency fine adjustment step is included, the frequency of the piezoelectric vibrating piece is set in advance even when the frequency fluctuates due to the joining of the cap to the base. It becomes possible to make it the frequency which did. Specifically, even when the frequency of the piezoelectric vibrating piece fluctuates due to the joining of the cap to the base, the frequency fluctuated by finely adjusting the frequency of the piezoelectric vibrating piece in the internal space Can be corrected. Therefore, fine adjustment of the frequency of the piezoelectric vibrating piece is performed in the internal space even when the piezoelectric vibrating piece is hermetically sealed from the base and the cap, that is, after the internal space is formed. The frequency can be corrected. In particular, when manufacturing the piezoelectric vibration device, it has undergone a thermal history such as an annealing process, a sealing process, a reflow process, etc., and the piezoelectric vibration piece adjusted in a milling process or a partial process through this thermal history. Although the frequency (oscillation frequency) varies, according to the present invention, since the frequency of the piezoelectric vibrating piece is varied by the frequency variable member after passing through the thermal history, the piezoelectric vibrating piece that fluctuated through the thermal history described above can be obtained. It is possible to finely adjust the frequency to suppress a frequency deviation defect.

  In addition, according to the present invention, since the pressure reducing step is included, the internal pressure can be lowered in the internal space by the getter material. Therefore, it becomes possible to prevent the series resonance resistance value of the piezoelectric vibration device from increasing. In particular, when the piezoelectric vibration device is manufactured, it undergoes a thermal history such as an annealing process, a sealing process, and a reflow process, and the series resonance resistance value of the piezoelectric vibrating piece increases through this thermal history. It is possible to prevent the series resonance resistance value of the piezoelectric vibrating piece from increasing by lowering the internal pressure by the pressure lowering step.

  Furthermore, according to the present invention, the frequency fine adjustment step and the pressure reduction step are alternately performed, so that the piezoelectric vibrating piece is hermetically sealed from the base and the cap, that is, the internal space is formed. After that, it is preferable to adjust the frequency of the piezoelectric vibrating piece and to reduce the pressure in the internal space, thereby improving the efficiency of the manufacturing process.

  According to the piezoelectric vibrating device and the manufacturing method thereof according to the present invention, even if the frequency of the piezoelectric vibrating piece varies due to the joining of the cap to the base, the frequency of the piezoelectric vibrating piece is set to a preset frequency. I can.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, a case where the present invention is applied to a crystal resonator as a piezoelectric vibration device is shown.

  As shown in FIG. 1, the crystal resonator 1 according to this example includes two crystal vibrating pieces 2 and 3 (piezoelectric vibrating pieces referred to in the present invention) formed by a photolithography method, and these crystal vibrating pieces 2 and 3. And a cap 12 for hermetically sealing the quartz crystal vibrating pieces 2 and 3 held on the base 11.

  In this crystal unit 1, as shown in FIG. 1, a base 11 and a cap 12 are joined to form a package 13 as a housing, and an airtightly sealed internal space 14 is formed in the package 13. The In addition, on the base 11 of the internal space 14, two crystal vibrating pieces 2 and 3 are bonded and held to the base 11 using a conductive bonding material (such as an adhesive or a bump) (not shown).

  Next, each configuration of the crystal resonator 1 will be described.

  As shown in FIG. 1, the base 11 is formed in a box-like body composed of a bottom portion and a wall portion extending upward from the bottom portion. The base 11 is formed by integrally firing a rectangular parallelepiped of a ceramic material on a single plate having a rectangular shape in plan view made of a ceramic material that is a non-light transmissive member. Moreover, the wall part is shape | molded along the surface outer periphery of a bottom part. The upper surface of the wall portion is a bonding area with the cap 12, and a metallized layer (not shown) for bonding with the cap 12 is provided in the bonding area.

  Further, as shown in FIG. 1, step portions 151 to 153 are formed on the side wall in the internal space 14 of the base 11 which is laminated and fired integrally in a concave shape. On the step portion 151, a separation plate 4 described below is provided. At this time, one opposing side 41 of the separation plate 4 is held by the step portion 151. On the step portions 152 and 153, electrode pads 51 to 54 that are electrically connected to excitation electrodes 22, 23, 32, and 33 described below of the two crystal vibrating pieces 2 and 3 are formed. Two crystal vibrating pieces 2 and 3 are provided to be held on .about.54.

  Moreover, the electrode pads 51-58 formed in the step parts 151-153 of the base 11 in the internal space 14 are terminal electrodes formed on the back surface 16 of the base 11 via the corresponding connection electrodes 61-68. The terminal electrodes 71 to 78 are electrically connected to external electrodes of external components and external devices. The electrode pads 51 to 58, the connection electrodes 61 to 68, and the terminal electrodes 71 to 78 are formed by printing integrally with the base 11 after printing a metallized material such as tungsten or molybdenum. Some of the electrode pads 51 to 58, the connection electrodes 61 to 68, and the terminal electrodes 71 to 78 are formed by forming nickel plating on the metallized upper portion and forming gold plating on the upper portion.

  The cap 12 is made of a metal material which is a non-light transmissive member, and is formed into a single plate having a rectangular shape in plan view as shown in FIG. The cap 12 has a brazing material (not shown) formed on the lower surface, and is joined to the base 11 by a technique such as seam welding or beam welding, so that the package 13 of the crystal unit 1 composed of the cap 12 and the base 11 is formed. Composed. The internal space 14 in the present embodiment refers to a portion hermetically sealed by the cap 12 and the base 11. The cap may be made of a ceramic material and hermetically sealed through a glass material.

  As shown in FIG. 1, the two crystal vibrating pieces 2 and 3 are arranged on the base 11 in the inner space 14 in a stacked manner. Thus, the package 13 can be reduced in size by arranging the two quartz crystal vibrating pieces 2 and 3 in a stacked manner.

  As shown in FIG. 1, a quartz crystal vibrating piece 2 (hereinafter referred to as an upper crystal vibrating piece) disposed above the internal space 14 is a tuning fork type quartz crystal vibrating piece, and is formed from a substrate that is a crystal piece of anisotropic material. Etching is formed. The substrate includes a base portion 21 and two leg portions 22 and 23 (first leg portion and second leg portion), and the first and second leg portions 22 and 23 extend from the base portion 21. .

  The upper quartz crystal vibrating piece 2 includes two excitation electrodes 24 and 25 (first excitation electrode and second excitation electrode) configured with different potentials, and these first and second excitation electrodes 24 and 25 are connected to electrode pads 51 and 25, respectively. In order to be electrically connected to 52, lead electrodes 26 and 27 drawn from the first and second excitation electrodes 24 and 25 are formed. Then, the extraction electrodes 26 and 27 and the electrode pads 51 and 52 are bonded through a conductive bonding material (not shown), and the extraction electrodes 26 and 27 and the electrode pads 51 and 52 are electrically connected.

  The first excitation electrode 24 is configured by connecting a first main surface electrode formed on both main surfaces of the first leg portion 22 and a second side surface electrode formed on both side surfaces of the second leg portion 23. The

  Similarly, the second excitation electrode 25 is connected to the second main surface electrode formed on both main surfaces of the second leg portion 23 and the first side surface electrode formed on both side surfaces of the first leg portion 24. Configured.

  Further, the tips of the first and second leg portions 22 and 23 of the upper crystal vibrating piece 2 are set as a substrate region 28 for frequency adjustment, as shown in FIG.

  As shown in FIG. 1, the quartz crystal vibrating piece 3 (hereinafter referred to as a lower quartz crystal vibrating piece) disposed below the internal space 14 is a tuning fork type quartz crystal vibrating piece, and a substrate that is a quartz piece made of anisotropic material. Is formed by etching. The substrate is composed of a base 31 and two legs 32 and 33 (third leg and fourth leg), and the third and fourth legs 32 and 33 extend from the base 31. Yes.

  The lower crystal vibrating piece 3 includes two excitation electrodes 34 and 35 (third excitation electrode and fourth excitation electrode) configured with different potentials, and these third and fourth excitation electrodes 34 and 35 connected to an electrode pad 53. , 54, lead electrodes 36, 37 drawn from the third and fourth excitation electrodes 34, 35 are formed. Then, the extraction electrodes 36 and 37 and the electrode pads 53 and 54 are bonded through a conductive bonding material (not shown), and the extraction electrodes 36 and 37 and the electrode pads 53 and 54 are electrically connected.

  The third excitation electrode 34 is configured by connecting third main surface electrodes formed on both main surfaces of the third leg portion 32 and fourth side electrodes formed on both side surfaces of the fourth leg portion 33. The

  Similarly, the fourth excitation electrode 35 is connected to the fourth main surface electrode formed on both main surfaces of the fourth leg portion 33 and the third side surface electrode formed on both side surfaces of the third leg portion 32. Configured.

  Further, the tips of the third and fourth leg portions 32 and 33 of the lower crystal vibrating piece 3 are set as a substrate region 38 related to frequency adjustment as shown in FIG.

  The first to fourth excitation electrodes 22, 23, 32, and 33 are, for example, laminated thin films composed of a chromium base electrode layer and a gold upper electrode layer. This thin film is formed on the entire surface by a technique such as vacuum deposition, and then formed into a desired shape by metal etching using a photolithography technique. The lead electrodes 26, 27, 36, and 37 are, for example, laminated thin films composed of a chromium base electrode layer, a gold intermediate electrode layer, and a chromium upper electrode layer. This thin film is formed on the entire surface by a technique such as vacuum deposition, and then formed into a desired shape by metal etching using a photolithography technique. Only the upper electrode layer of chromium is partially masked to form a vacuum deposition process or the like. It is formed by the method of.

  Then, the extraction electrodes 26 and 27 of the upper crystal vibrating piece 2 and the electrode pads 51 and 52 of the base 11 are bonded by a conductive bonding material, and as shown in FIG. 21 is held in one piece by the base 11. Similarly, the extraction electrodes 36 and 37 of the lower crystal vibrating piece 3 and the electrode pads 53 and 54 of the base 11 are bonded by a conductive bonding material, and as shown in FIG. 3 is held by the base 11 at the base 31.

  By the way, between the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 arranged in a stacked manner in the internal space 14, there are substrates related to the frequency adjustment of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3. An insulating separation plate 4 having at least partitions of the regions 28 and 38 is interposed. As shown in FIG. 1, the separation plate 4 is provided on a step portion 151 formed on the side wall of the internal space 14 so that a part thereof (one opposing side 41 of the separation plate 4) is held. . In this embodiment, quartz is used as the material of the separation plate 4. The separation plate 4 is formed by a photolithographic method similarly to the upper side crystal vibrating piece 2 and the lower side crystal vibrating piece 3. As described above, in this embodiment, since the quartz that is the insulating material is used for the separation plate 4, for example, the separation plate 4 is formed by etching using, for example, a photolithography method compared with the metal that is the conductive material. It is easy to mold into a preset shape. Further, since the separation plate 4 is formed by the photolithographic method similarly to the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3, the manufacturing equipment for manufacturing the separation plate 4 is used as the upper crystal vibrating piece 2 and the lower crystal vibrating piece 2. Sharing with the manufacturing equipment which manufactures the vibration piece 3 can be achieved. Moreover, by using a shared manufacturing facility, the manufacturing site can be made the same place, which is effective in terms of quality control and reliability.

  As described above, the separation plate 4 at least partitions the substrate regions 28 and 38 related to the frequency adjustment of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 respectively. Specifically, as shown in FIG. 1, the separation plate 4 has an upper crystal vibration over the longitudinal direction of the first to fourth legs 22, 23, 32, 33 of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3. The piece 2 and the lower crystal vibrating piece 3 are partitioned. The substrate regions 28 and 38 related to frequency adjustment here include not only the substrate region for frequency adjustment but also the substrate region for the portion related to frequency adjustment. For example, when performing frequency adjustment, plasma is applied during etching adjustment. Includes a substrate region that is affected by wraparound and a substrate region that is affected by deposition of a deposited material when weighting (evaporation adjustment) of the substrate is performed.

  Concave portions 42 are formed on both main surfaces (front and back main surfaces) of the separation plate 4 facing the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3. The first and second leg portions 22 and 23 of the vibrating piece 2 and the third and fourth leg portions 32 and 33 of the lower crystal vibrating piece 3 are arranged. That is, the inner bottom surface 43 of the recess 42 is disposed in the vicinity of the free ends that are the tips of the first to fourth leg portions 22, 23, 32, 33 of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3. Thus, in this embodiment, the concave portions 42 are formed on both main surfaces of the separation plate 4, and the inner bottom surface 43 of the concave portion 42 is the first to fourth legs of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3. Since it is arranged in the vicinity of the free end that is the tip of the portions 22, 23, 32, 33, even if the free end is displaced when the crystal resonator 1 is subjected to a mechanical impact, the upper side crystal vibration Contact of the piece 2 and the lower crystal vibrating piece 3 to the separation plate 4 can be avoided. For example, the free end swings up and down due to mechanical impact, but by forming the recess 42 directly above and below the free end, it is possible to avoid the free end from touching the inner bottom surface 43 of the recess 42. Further, when the upper crystal vibrating piece 2 is disposed on the base 11, the flat portions of both main surfaces, that is, the top surface of the recess 42 functions as a pillow portion.

  Further, on both main surfaces of the separation plate 4 arranged in the internal space, frequency variable portions 81 and 82 for varying the frequencies of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 are respectively provided on the upper crystal vibration. It is provided to face the substrate regions 28 and 38 related to the frequency adjustment of the piece 2 and the lower crystal vibrating piece 3. The frequency variable portions 81 and 82 are made of a low melting point metal material, and in this embodiment, are made of tin, indium, or the like. The frequency variable portions 81 and 82 are evaporated by being electrically heated, and the evaporated frequency variable members 81 and 82 are vapor-deposited on the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 to be hermetically sealed. This is for finely adjusting the frequencies of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 in the internal space 14.

  Therefore, heating electrodes 83 and 84 for electrically heating the frequency variable portions 81 and 82 (in this embodiment, molybdenum, titanium, or the like) are formed on the separation plate 4. The heating electrodes 83 and 84 correspond to the terminal electrodes 75 to 58 formed on the back surface 16 of the base 11 through the electrode pads 55 to 58 and the connection electrodes 65 to 68 provided on the step portion 151. The terminal electrodes 75 to 78 are connected to an external power source (not shown). Note that the electrode pads 55 to 58, the connection electrodes 65 to 68, and the terminal electrodes 75 to 78 used here may be electrodes that have been used as ground electrodes or dummy electrodes in the existing crystal resonator. The electrode pads 55 to 58, the connection electrodes 65 to 68, and the terminal electrodes 75 to 78 are formed by printing integrally with the base 11 after printing a metallized material such as tungsten or molybdenum. And some of the electrode pads 55-58, the connection electrodes 65-68, and the terminal electrodes 75-78 are formed by forming nickel plating on the upper part of the metallization and forming gold plating on the upper part thereof.

  The present invention includes the electrode pads 51 to 54, the connection electrodes 61 to 64, and the terminal electrodes 71 to 74 having the same names, and the electrode pads 51 to 58, the connection electrodes 61 to 68, and the terminal electrodes 71 to 78. The base electrodes 91 to 98 are configured. That is, the base 11 is formed with a plurality of base electrodes 91 to 98 that are drawn from the inner surface 17 facing the internal space 14 of the base 11 to the outer surface 18 that is the outer peripheral surface of the base 11. The base electrodes 91 to 94 correspond to a part of the plurality of base electrodes referred to in the present invention, and the base electrodes 95 to 98 correspond to the other parts of the plurality of base electrodes referred to in the present invention. The other part of the plurality of base electrodes referred to in the present invention is not all the remaining bases other than a part of the plurality of base electrodes, but the remaining part other than a part of the plurality of base electrodes. Also good. That is, other portions of the plurality of base electrodes may be used not only as electrodes for electrically heating the frequency variable portions 81 and 82 but also as ground electrodes and dummy electrodes.

  Final frequency adjustment and fine adjustment of the crystal unit 1 having the above-described configuration are performed as follows. First, the lower crystal vibrating piece 3 is held by the step portion 153 of the base 11 and the final frequency adjustment of the lower crystal vibrating piece 3 is performed. After finishing the final frequency adjustment of the lower crystal vibrating piece 3, the separation plate 4 is provided on the step portion 151 in the sky. Then, the upper crystal vibrating piece 2 is held by the step portion 152 of the base 11 above the separation plate 4, the final frequency adjustment of the upper crystal vibrating piece 2 is performed, and the final frequency adjustment of the crystal resonator 1 is performed. Is called.

  Then, the cap 12 is joined to the base 11 by a technique such as seam welding or beam welding, and the package 13 of the crystal unit 1 is formed by the cap 12 and the base 11 (the internal space 14 of the package 13 is formed). The upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 are hermetically sealed in the internal space 14. After the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 are hermetically sealed in the internal space 14, the frequency variable portions 81 and 82 provided on both main surfaces of the separation plate 4 are interposed via base electrodes 95 to 98. Then, the same amount of voltage is supplied from the same external power source to be electrically heated. The frequency variable portions 81 and 82 are evaporated by heating, and the evaporated frequency variable portions 81 and 82 are deposited on the substrate regions 28 and 38 related to the frequency adjustment of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3, Fine adjustment is performed so as to lower the frequencies of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 in the hermetically sealed internal space 14 (frequency fine adjustment step in the present invention). In the present embodiment, fine adjustment is performed to reduce the frequency values of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3, and the frequencies of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 are adjusted at the time of the final frequency adjustment described above. Adjust to the frequency.

  As described above, according to the crystal resonator 1 according to the present embodiment, the frequency variable portions 81 and 82 for changing the frequencies of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 are provided in the internal space 14. Since the frequency variable portions 81 and 82 are electrically heated and the frequencies of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 are changed, the upper crystal vibration is caused by the joining of the cap 12 to the base 11. Even when the frequencies of the piece 2 and the lower crystal vibrating piece 3 vary, the frequencies of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 can be set to preset frequencies. Specifically, even when the frequencies of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 fluctuate due to the joining of the cap 12 to the base 11, the changed upper crystal vibrating piece 2 and the lower crystal vibration are changed. The frequency of the piece 3 can be corrected to the frequency at the time of final frequency adjustment. In other words, the fluctuating frequency can be corrected by finely adjusting the frequencies of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 in the internal space 14. Therefore, the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 are hermetically sealed from the base 11 and the cap 12, that is, even after the internal space 14 is formed, the upper crystal vibrating piece in the inner space 14. The frequency can be corrected by finely adjusting the frequencies of the second and lower crystal vibrating pieces 3. In particular, when the crystal resonator 1 is manufactured, it has undergone a thermal history such as an annealing step, a sealing step, and a reflow step, and through this thermal history, an upper side crystal resonator piece adjusted in a milling step or a partial step 2 and the lower crystal vibrating piece 3 fluctuate (oscillation frequency). However, according to this embodiment, the upper and lower crystal vibrating pieces 2 and 3 are moved by the frequency variable portions 81 and 82 after passing through the thermal history. Therefore, the frequency deviation defects can be suppressed by finely adjusting the frequencies of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 that have fluctuated through the thermal history described above.

  Furthermore, as described above, according to the crystal resonator 1 according to the present embodiment, the upper crystal vibrating piece 2 and the lower side are disposed between the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 in the internal space 14. Since the insulating separation plate 4 having at least a partition wall between the substrate regions 28 and 38 related to the frequency adjustment of the crystal vibrating piece 3 is interposed, the frequency adjustment of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 is adjusted. It can also be done independently. As a result, when the frequency of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 is adjusted, when the respective frequencies of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 are individually adjusted, the frequency adjustment is not performed. It is possible to prevent interference related to frequency adjustment to the crystal vibrating piece (lower crystal vibrating piece 3 when performing frequency adjustment of the upper crystal vibrating piece 2). Specifically, it is possible to suppress a metal material or the like that scatters when adjusting the frequency of the upper crystal vibrating piece 2 from adhering to the lower crystal vibrating piece 3 and changing the frequency of the lower crystal vibrating piece 3. As described above, the crystal resonator 1 according to the present embodiment is an optimum form for adjusting the frequency of the crystal resonator element.

  Further, since the package 13 is made of a non-light transmissive member, the frequency of the frequency variable sections 81 and 82 cannot be adjusted by a laser or the like from the outside of the package 13. However, according to the present embodiment, the frequency variable portions 81 and 82 are electrically heated in the internal space 14 so that the frequencies of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 are changed. Even after the step is formed, the frequency of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 can be finely adjusted in the internal space 14.

  Further, the excitation electrodes 22, 23, 32, and 33 of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 are connected to the base electrodes 91 to 94, and the frequency variable portions 81 and 82 are connected to the base electrodes 95 to 98. Therefore, an external power source is connected to the base electrodes 95 to 98 to which the frequency variable portions 81 and 82 are connected, and the voltage is supplied from the external power source, whereby the frequency variable portions 81 and 82 are heated, and the frequency is increased by this heating. The variable portions 81 and 82 evaporate, and the evaporated frequency variable portions 81 and 82 adhere to the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 to cause the frequencies of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3. Is variable. Further, as described above, an existing base electrode such as a ground electrode or a dummy electrode can be used without newly designing a base electrode exclusively for the frequency variable sections 81 and 82, and an existing base is used. You can also Further, the upper crystal resonator element 2 and the lower crystal resonator element 3 are hermetically sealed from the base 11 and the cap 12, that is, even after the internal space 14 is formed, the upper crystal oscillator piece in the internal space 14. 2 and the lower crystal vibrating piece 3 are preferably finely adjusted to correct the frequency.

  Further, since the frequency variable portions 81 and 82 are made of a material having a low melting point, it is preferable that only the frequency variable portions 81 and 82 generate heat without causing other components to generate heat.

  Further, as described above, according to the manufacturing method (frequency adjusting step) of the crystal resonator 1 according to the present embodiment, since the fine frequency adjusting step is included, the cap 12 is bonded to the base 11. Even when the frequency varies due to the bonding, the frequencies of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 can be set to preset frequencies. Specifically, even when the frequencies of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 fluctuate due to the joining of the cap 12 to the base 11, the upper crystal vibrating piece 2 and the lower crystal resonator 2 in the internal space 14 are changed. It is possible to correct the fluctuating frequency by finely adjusting the frequency of the side crystal vibrating piece 3. Therefore, the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 are hermetically sealed from the base 11 and the cap 12, that is, even after the internal space 14 is formed, the upper crystal vibrating piece in the inner space 14. The frequency can be corrected by finely adjusting the frequencies of the second and lower crystal vibrating pieces 3. In particular, when the crystal resonator 1 is manufactured, it has undergone a thermal history such as an annealing step, a sealing step, and a reflow step, and through this thermal history, an upper side crystal resonator piece adjusted in a milling step or a partial step 2 and the frequency of the lower crystal vibrating piece 3 vary, but according to the present embodiment, the frequency of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 can be changed by the frequency variable portions 81 and 82 after passing through the thermal history. Therefore, the frequency deviation defect can be suppressed by finely adjusting the frequencies of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 that have changed through the above-described thermal history.

  In the above-described embodiment, an external power source is connected to the base electrodes 95 to 98 to which the frequency variable portions 81 and 82 are connected, and the frequency variable portions 81 and 82 are heated by voltage supply from the external power source. However, the configuration for electrically heating the frequency variable sections 81 and 82 is not limited to this. For example, as shown in FIG. 2, electromagnetic induction heating members 85 and 86 (generally magnetized for electromagnetic induction heating of the frequency variable portions 81 and 82 in the internal space 14. In this embodiment, The structure provided with copper, SUS, etc. may be sufficient. As described above, since the electromagnetic induction heating members 85 and 86 for electromagnetic induction heating the frequency variable portions 81 and 82 are provided in the internal space 14, a current is supplied to the frequency variable portions 81 and 82 by electromagnetic induction. The frequency variable portions 81 and 82 are heated by the generated current, and the frequency variable portions 81 and 82 are evaporated by the heating, and the evaporated frequency variable portions 81 and 82 are the upper crystal vibrating piece 2 and the lower crystal vibration. The frequency of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 attached to the piece 3 is varied. Therefore, the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 are hermetically sealed from the base 11 and the cap 12, that is, even after the internal space 14 is formed, the upper crystal vibrating piece in the inner space 14. 2 and the lower crystal vibrating piece 3 are preferably finely adjusted to correct the frequency. Further, after finely adjusting the frequency of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 after forming the internal space 14, the frequency at which the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 are opened to the atmosphere. Variable elements can be eliminated.

  In the above-described embodiment, the frequency variable portions 81 and 82 are used for the upper crystal resonator element 2 and the lower crystal resonator element 3, respectively. However, the present invention is not limited to this, and the frequency variable sections 81 and 82 are connected to different external power sources via base electrodes 95 to 98, and different voltages are applied to the frequency variable sections 81 and 82, respectively. It may be supplied. Alternatively, the design may be changed so that different voltages are supplied to the frequency variable sections 81 and 82 from one external power source.

  In the above-described embodiment, the frequency variable portions 81 and 82 are connected to the base electrodes 95 to 98 via the heating electrodes 83 and 84. However, the present invention is not limited to this, and FIG. As shown, the frequency variable portions 81 and 82 may be directly connected to the base electrodes (for example, the base electrodes 95 and 96) on the base bottom surface 19 of the internal space 14. In this case, it is preferable to use tungsten, molybdenum or the like as the material of the base electrode.

  In the above-described embodiment, the number of crystal vibrating pieces is two. However, the present invention is not limited to this, and three or more crystal vibrating pieces can be used according to the application. At this time, the shape of the package is changed in accordance with the number of crystal vibrating pieces to be used, and the separation plate 4 is interposed between each of three or more crystal vibrating pieces, so that only the crystal resonator according to the above-described embodiment is provided. Instead, it can be used as any piezoelectric vibration device having other different functions. Alternatively, as shown in FIG. 3, the number of crystal vibrating pieces may be one. In the crystal resonator 1 shown in FIG. 3, frequency variable portions 81 and 82 are provided directly on the base 11 without using the separation plate 4. Further, in this crystal resonator 1, two frequency variable portions 81 and 82 are used for one crystal vibrating piece (for example, the crystal vibrating piece 2). As described above, the frequency variable sections 81 and 82 may be provided in any position as long as they are within the internal space 14, and are preferably disposed appropriately in a place where the frequency adjustment efficiency is high. The number of frequency variable members for one crystal vibrating piece 2 is not limited.

  In the above-described embodiment, the separation plate 4 is provided on the side wall of the internal space 14, but is not limited to this. For example, as shown in FIG. May be. In the crystal unit 1 shown in FIG. 4, the separation plate 4 protrudes from the base bottom surface 19 of the internal space 14 and is bent, and a frequency variable member (for example, a frequency variable member as an example) 81).

  In the above-described embodiment, at least the substrate regions 28 and 38 related to the frequency adjustment of the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 are partitioned by the separation plate 4, but the present invention is not limited to this. For example, the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 may be completely separated by the separating plate 4.

  Further, in the above-described embodiment, the tuning fork type crystal vibrating piece is applied to the upper side crystal vibrating piece 2 and the lower side crystal vibrating piece 3 shown in FIG. 1. However, the present invention is not limited to this. A type quartz crystal vibrating piece and an AT-cut quartz crystal vibrating piece may be used. Two AT-cut quartz crystal vibrating pieces may be used. That is, any piezoelectric vibrating piece can be applied.

  Further, in the above-described embodiment, quartz is used as the material of the separation plate 4, but the material is not limited to this, and glass or ceramic may be used as long as it is an insulating material. In addition, when glass is used for the material of the separation plate 4, the separation plate 4 is shape | molded by an etching process. Further, when ceramic is used as the material of the separation plate 4, the separation plate 4 is formed by press working.

  In the above-described embodiment, the frequency is adjusted by the frequency variable members 81 and 82 after the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 are hermetically sealed, but this is a preferable example. is there. Therefore, the present invention is not limited to this, and the frequency may be changed in advance by the frequency variable members 81 and 82 before the upper crystal vibrating piece 2 and the lower crystal vibrating piece 3 are hermetically sealed.

  In the above-described embodiment, a getter material 89 that lowers the pressure in the internal space 14 (hereinafter referred to as internal pressure) may be provided in the internal space 14. In this embodiment, titanium is used as the getter material. For example, as shown in FIG. 5, a quartz crystal resonator element (for example, crystal oscillator piece 2; the same applies hereinafter) and a separation plate 4 (getter material and crystal oscillator piece in the present invention) A frequency variable member (for example, a frequency variable member 81; the same applies hereinafter) is provided on the main surface 44 of the separation plate 4 facing the crystal vibrating piece 2, and the other main surface 45 is a getter material. 89 may be provided. In the configuration shown in FIG. 5, the frequency variable member 81 and the getter material 89 are connected to different base electrodes 95 to 98 via heating electrodes 83 and 84, respectively. Furthermore, the getter material 89 is disposed at a position to be isolated from the crystal vibrating piece 2 as shown in FIG.

  In the crystal unit 1 shown in FIG. 5, the frequency variable member 81 is heated via the base electrodes 95 and 96 and the heating electrode 83 by supplying electrodes to the frequency variable member 81 from an external power source. The frequency variable member 81 evaporates, and the evaporated frequency variable member 81 adheres to the crystal vibrating piece 2 to vary the frequency of the crystal vibrating piece 2 (frequency fine adjustment step in the present invention). Then, when the getter material 89 is supplied with an electrode from an external power source, the getter material 89 is heated via the base electrodes 97 and 98 and the heating electrode 84, and the getter material 89 is evaporated by this heating, and the getter material 89 is evaporated. The material collects gas molecules that are generated when the cap 12 is joined to the base 11 and remains in the internal space 14 to reduce the internal pressure (pressure reduction step in the present invention). Then, the crystal resonator 1 is manufactured by alternately performing the frequency fine adjustment step and the pressure reduction step.

  As shown in the crystal resonator 1 according to the above-described embodiment, the getter material 89 for reducing the internal pressure is provided in the internal space 14, and the internal pressure can be lowered in the internal space 14 by the getter material 89. Therefore, it is possible to prevent the series resonance resistance value of the crystal resonator 1 from increasing. In particular, it is preferable to reduce the internal pressure after the quartz resonator element 2 is hermetically sealed from the base 11 and the cap 12, that is, after the internal space 14 is formed.

  In addition, since the separating plate 4 that shields the getter material 89 and the crystal vibrating piece 2 is provided between the getter material 89 and the crystal vibrating piece 2, the crystal in the internal space 14 when the getter material 89 is evaporated. It is possible to prevent the getter material 89 that has collected gas molecules from adhering to the vibrating piece 2.

  Further, since the getter material 89 is disposed at a position isolated from the crystal vibrating piece 2, the getter material 89 that has collected gas molecules in the crystal vibrating piece 2 in the internal space 14 when the getter material 89 is evaporated is provided. Adhesion can be prevented. Further, when the tuning fork type crystal vibrating piece 2 is used as shown in the present embodiment, the series resonance resistance value can be improved in a state where there is almost no frequency fluctuation.

  Furthermore, according to the method for manufacturing the crystal unit 1 according to the above-described embodiment, the internal pressure can be lowered by the getter material 89 because the pressure reducing step is included. Therefore, it is possible to prevent the series resonance resistance value of the crystal resonator 1 from increasing. In particular, when the crystal resonator 1 is manufactured, a thermal history such as an annealing process, a sealing process, and a reflow process is performed, and the series resonance resistance value of the crystal vibrating piece 2 is increased by passing through the thermal history. However, according to the present embodiment, it is possible to prevent the series resonance resistance value of the quartz crystal vibrating piece 2 from increasing by reducing the internal pressure by the pressure lowering step.

  In addition, since the frequency fine adjustment step and the pressure reduction step are alternately performed, the crystal vibrating piece 2 is hermetically sealed from the base 11 and the cap 12, that is, the frequency of the crystal vibrating piece 2 after the internal space 14 is formed. It is preferable that the internal force is reduced and the efficiency of the manufacturing process is improved.

  Next, a crystal resonator provided with a getter material 89 according to another embodiment other than the crystal resonator 1 shown in FIG. 5 will be described. Note that, in the crystal resonator described below, a configuration different from the configuration of the crystal resonator 1 shown in FIG. 5 will be described, and description of the same operational effects as the crystal resonator 1 shown in FIG. 5 will be omitted.

  In the crystal unit 1 shown in FIG. 6, the crystal resonator element 2 and the separation plate 4 are provided in the internal space 14 of the crystal unit 1, and the frequency of the main surface 44 of the isolation plate 4 facing the crystal unit 2 is variable. A member 81 is provided. Further, a getter material 89 is provided on the base 11 in the internal space 14, and the getter material 89 and the crystal vibrating piece 2 are blocked by the separation plate 4 without facing each other. In the configuration shown in FIG. 6, the frequency variable member 81 is connected to the base electrodes 95 and 96 via the heating electrode 83. The getter material 89 is directly connected to the base electrodes 97 and 98 on the base bottom surface 19 of the internal space 14.

  In the crystal unit 1 shown in FIG. 7, the crystal resonator element 2 is held in a step portion 152 in the internal space 14 of the crystal unit 1, and the frequency variable member 81 and the getter material 89 are formed on the base bottom surface 19 in the internal space 14. Is provided. The frequency variable member 81 is opposed to the substrate region 28 related to the frequency adjustment of the crystal vibrating piece 2. Further, the getter material 89 is disposed at a position to be isolated from the crystal vibrating piece 2.

  In the crystal resonator 1 shown in FIG. 8, the crystal resonator element 2 and the separation plate 4 are provided in the internal space 14 of the crystal resonator 1. The separation plate 4 protrudes from the base bottom surface 19 of the internal space 14 and is bent, and a frequency variable member 81 and a getter material 89 are provided at the tip of the bent separation plate 4. The frequency variable member 81 is arranged to face the substrate region 28 related to the frequency adjustment of the crystal vibrating piece 2 of the separation plate 4 (see reference numeral 44 in FIG. 8). The getter material is disposed on the main surface 45 that does not face the crystal vibrating piece 2 and is isolated from the crystal vibrating piece 2.

  In the crystal unit 1 shown in FIG. 9, the crystal resonator element 2 is held in a step portion 152 in the internal space 14 of the crystal unit 1, and the frequency variable member 81 and the getter material 89 are in the cap 12 in the internal space 14. Is provided. The frequency variable member 81 is opposed to the substrate region 28 related to the frequency adjustment of the crystal vibrating piece 2. Further, the getter material 89 is disposed at a position to be isolated from the crystal vibrating piece 2. Further, the cap 12 is made of ceramic, and base electrodes 95 and 96 connected to the frequency variable member and base electrodes 97 and 98 connected to the getter material 89 are formed to penetrate therethrough.

  Further, the structure of the crystal unit 1 provided with the frequency variable member 81 and the getter material 89 shown in FIGS. 5 to 9 is electromagnetic induction instead of the heating electrode 83 (or 83, 84) as shown in FIG. It is good also as a structure which provided the heating member 85 (or 85,86) and performed electromagnetic induction heating.

  The present invention can be implemented in various other forms without departing from the spirit or main features thereof. For this reason, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is indicated by the claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  The present invention can be applied to a piezoelectric vibration device such as a crystal resonator and a manufacturing method thereof.

FIG. 1 is a schematic configuration diagram of a crystal resonator according to the present embodiment. Specifically, FIG. 1A is a schematic plan view of the crystal resonator with the cap removed. FIG. 1B is a sectional view taken along line XX of the crystal unit shown in FIG. FIG. 2 is a schematic cross-sectional view of a crystal resonator using electromagnetic induction heating according to the present embodiment. FIG. 3 is a schematic cross-sectional view of a crystal resonator in which a frequency variable member is directly provided on the bottom surface of the base according to the present embodiment. FIG. 4 is a schematic cross-sectional view of a quartz resonator according to the present embodiment, in which the form of the separation plate is changed. FIG. 5 is a schematic cross-sectional view of a crystal resonator provided with a getter material according to the present embodiment. FIG. 6 is a schematic cross-sectional view of a crystal resonator provided with a getter material according to this example. FIG. 7 is a schematic cross-sectional view of a crystal resonator in which a frequency variable member and a getter material are directly provided on the bottom surface of the base according to the present embodiment. FIG. 8 is a schematic cross-sectional view of a crystal resonator according to the present embodiment, in which the form of the separation plate is changed and a getter material is provided. FIG. 9 is a schematic cross-sectional view of a crystal resonator in which a frequency variable member and a getter material are provided on a cap according to the present embodiment.

Explanation of symbols

1 Crystal resonator (piezoelectric vibration device)
DESCRIPTION OF SYMBOLS 11 Base 12 Cap 13 Package 14 Inner space 17 Inner surface 18 facing inner space Outer surface 2 and 3 of base Crystal resonator element (piezoelectric resonator element)
24, 25, 34, 35 Excitation electrode (electrode formed on the piezoelectric vibrating piece)
4 Separation plate (shielding plate)
81, 82 frequency variable member,
83,84 heating electrode,
85, 86 Electromagnetic induction heating member,
89 Getter material 91-98 Base electrode

Claims (9)

A piezoelectric vibration device in which a cap is joined to a base to form a package, an internal space is formed in the package, and a piezoelectric vibration piece is held on the base in the internal space.
In the internal space, a frequency variable member for varying the frequency of the piezoelectric vibrating piece is provided,
The piezoelectric vibration device, wherein the frequency variable member is electrically heated to vary the frequency of the piezoelectric vibrating piece.   The piezoelectric vibration device according to claim 1, wherein the package is made of a non-light transmitting member. An electrode is formed on the piezoelectric vibrating piece,
The base is formed with a plurality of base electrodes drawn from an inner surface facing the internal space of the base to an outer surface which is an outer peripheral surface of the base,
The electrode formed on the piezoelectric vibrating piece is connected to a part of the plurality of base electrodes, and the frequency variable member is connected to the other part of the plurality of base electrodes. Item 3. The piezoelectric vibration device according to Item 1 or 2.   The piezoelectric vibration device according to claim 1, wherein an electromagnetic induction heating member for electromagnetically heating the frequency variable member is provided in the internal space.   The piezoelectric vibration device according to claim 1, wherein the frequency variable member is a low melting point material.   The piezoelectric vibration device according to claim 1, wherein a getter material for reducing the pressure in the internal space is provided in the internal space.   The piezoelectric vibration device according to claim 6, wherein a shielding plate that shields the getter material and the piezoelectric vibrating piece is provided between the getter material and the piezoelectric vibrating piece.   The piezoelectric vibration device according to claim 6, wherein the getter material is disposed at a position isolated from the piezoelectric vibration piece. A method for manufacturing a piezoelectric vibration device according to any one of claims 1 to 8,
After finely adjusting the frequency of the piezoelectric vibrating piece in the internal space by electrically heating the frequency variable member after joining the cap to the base and forming the internal space,
A pressure reduction step of reducing the pressure of the internal space in the internal space by the getter material after joining the cap to the base to form the internal space;
The method of manufacturing a piezoelectric vibration device, wherein the frequency fine adjustment step and the pressure reduction step are alternately performed.

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