Patent Publication Number: US-2016225978-A1

Title: Method of manufacturing vibration device

Description:
BACKGROUND 
     1. Technical Field 
     The present invention relates to a method of manufacturing a vibration device. 
     2. Related Art 
     In a process of manufacturing a vibrator on which a quartz crystal vibrator element is mounted, typically, after mounting the quartz crystal vibrator element on a package base, a frequency adjustment process of adjusting a frequency with respect to individual quartz crystal vibrator elements is carried out. 
     For example, JP-A-2009-44237 discloses a method in which after mounting the vibrator element on a package base, apart of an excitation electrode is etched through ion milling in which the excitation electrode is irradiated with an ion laser and the like, thereby carrying out frequency adjustment of the vibrator. 
     However, in the frequency adjustment process, even in a vibrator element having no problem in external appearance, there is a problem in that when the vibrator element does not resonate, the vibrator element becomes a defective product, and thus a yield ratio decreases. 
     SUMMARY 
     An advantage of some aspects of the invention is to provide a method of manufacturing a vibration device capable of improving a yield ratio during manufacturing. 
     The invention can be implemented as the following forms or application examples. 
     Application Example 1 
     A method of manufacturing a vibration device according to this application example includes strongly exciting a vibrator element by applying power, which is higher than drive power during use of the vibrator element, to the vibrator element, and adjusting a frequency of the vibrator element after the strongly exciting of the vibrator element. 
     In the method of manufacturing the vibration device, since the frequency adjustment of the vibrator element is carried out after strongly exciting the vibrator element, as described later, it is possible to reduce an equivalent series resistance value (CI value) of the vibrator element in a frequency adjustment process, and it is possible to improve an oscillation rate. Accordingly, according to the method of manufacturing the vibration device as described above, it is possible to improve a yield ratio during manufacturing of the vibration device. 
     Application Example 2 
     The method of manufacturing the vibration device according to the application example may further include forming the vibrator element in a substrate before the strongly exciting of the vibrator element. 
     The method of manufacturing the vibration device as described above includes the forming of the vibrator element in a substrate. Accordingly, it is possible to strongly excite the vibrator element, for example, in a state in which the vibrator element is formed in the substrate. In other words, in the method of manufacturing the vibration device, it is possible to strongly excite the vibrator element before the vibrator element is accommodated in a container. 
     According to this, in the method of manufacturing the vibration device, it is possible to reduce a possibility that foreign matter, which is attached to the vibrator element, enters the container of the vibration device. 
     Application Example 3 
     In the method of manufacturing the vibration device according to the application example, the strongly exciting of the vibrator element may include inspecting the vibrator element. 
     In the method of manufacturing the vibration device as described above, the inspecting is included in the process of strongly exciting the vibrator element, and thus it is possible to reduce transportation of a defective vibrator element that occurs in the strongly exciting process to the subsequent process. 
     Accordingly, it is possible to realize a reduction in a defective percentage in finished products of the vibration device, and thus it is possible to realize a reduction in the failure cost. 
     Application Example 4, Application Example 5 
     In the method of manufacturing the vibration device according to the application examples, a plurality of the vibrator elements may be formed in the substrate. 
     In the method of manufacturing the vibration device as described above, the vibrator elements are formed by using a so-called wafer substrate, and the strongly exciting is carried out, and thus it is possible to attain high productivity. 
     Application Example 6, Application Example 7 
     In the method of manufacturing the vibration device according to the application examples, the strongly exciting of the vibrator element may be carried out with respect to the plurality of vibrator elements which are formed in the substrate. 
     In the method of manufacturing the vibration device as described above, the strongly exciting of the vibrator element is carried out with respect to the plurality of vibrator elements which are formed in the substrate, and thus it is possible to attain high productivity. 
     Application Example 8 
     The method of manufacturing the vibration device according to the application example may further include joining the base and the vibrator element through a joining member before the strongly exciting of the vibrator element. 
     The method of manufacturing the vibration device as described above includes the joining of the base and the vibrator element through a joining member before the strongly exciting of the vibrator element, and thus it is possible to improve a yield ratio during manufacturing of the vibration device. 
     Application Example 9, Application Example 10, Application Example 11, Application Example 12 
     In the method of manufacturing the vibration device according to the application examples, in the strongly exciting of the vibrator element, power of 2.5 mW or more to 100 mW or less may be applied to the vibrator element. 
     In the method of manufacturing the vibration device as described above, as described later, it is possible to reduce the CI value of the vibrator element in the frequency adjustment process, and it is possible to improve an oscillation rate. 
     Application Example 13, Application Example 14, Application Example 15, Application Example 16 
     In the method of manufacturing the vibration device according to the application examples, the vibrator element may include a quartz crystal substrate including a vibration portion that vibrates with thickness shear vibration. 
     In the method of manufacturing the vibration device as described above, it is possible to improve a yield ratio during manufacturing of the vibrator. 
     Application Example 17 
     A method of manufacturing a vibration device according to this application example includes forming a vibrator element, joining a base and the vibrator element through a joining member, joining the base and a semiconductor device through a joining member, and applying power, which is higher than drive power during use of the vibrator element, to the vibrator element for strongly exciting before the joining of the semiconductor device. 
     In the method of manufacturing the vibration device as described above, it is possible to improve a yield ratio during manufacturing of an oscillator. In addition, in the method of manufacturing the oscillator, the vibrator element can also be strongly excited before the vibrator element is accommodated in a container, and thus it is possible to reduce a possibility that foreign matter, which is attached to the vibrator element, enters the container. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
         FIG. 1A  is a cross-sectional view schematically illustrating a vibrator according to a first embodiment, and  FIG. 1B  is a plan view schematically illustrating the vibrator according to the first embodiment. 
         FIG. 2  is a perspective view schematically illustrating a vibrator element of the vibrator according to the first embodiment. 
         FIG. 3  is a plan view schematically illustrating the vibrator element of the vibrator according to the first embodiment. 
         FIG. 4  is a cross-sectional view schematically illustrating the vibrator element of the vibrator according to the first embodiment. 
         FIG. 5  is a cross-sectional view schematically illustrating the vibrator element of the vibrator according to the first embodiment. 
         FIG. 6  is a perspective view schematically illustrating an AT-cut quartz crystal substrate. 
         FIG. 7  is a cross-sectional view schematically illustrating the vibrator element of the vibrator according to the first embodiment. 
         FIG. 8  is a flowchart illustrating an example of a method of manufacturing the vibrator according to the first embodiment. 
         FIG. 9  is a cross-sectional view schematically illustrating a process of manufacturing the vibrator according to the first embodiment. 
         FIG. 10  is a graph illustrating a relationship between a drive level and a variation ratio of a CI value. 
         FIG. 11  is a graph illustrating a relationship between the drive level and an oscillation rate. 
         FIGS. 12A and 12B  illustrate a vibrator that is obtained by a method of manufacturing the vibrator according to a second embodiment,  FIG. 12A  is an external appearance plan view, and  FIG. 12B  is a cross-sectional view taken along line A-A′ in  FIG. 12A . 
         FIGS. 13A to 13C  are flowcharts illustrating the method of manufacturing the vibrator according to the second embodiment. 
         FIGS. 14A to 14D  illustrate a process of forming a vibrator element of the vibrator according to the second embodiment,  FIG. 14A  is an external appearance perspective view of a wafer including a plurality of vibration elements,  FIG. 14B  is an enlarged plan view of a B portion in  FIG. 14A , and  FIGS. 14C and 14D  are enlarged plan views illustrating a state in which an electrode is formed in each of the vibration elements. 
         FIGS. 15A and 15B  are external appearance perspective views illustrating a process of strongly exciting the vibrator according to the second embodiment. 
         FIGS. 16A to 16C  are cross-sectional views illustrating a process of accommodating the vibrator according to the second embodiment. 
         FIGS. 17A and 17B  illustrate an oscillator obtained by a method of manufacturing the oscillator according to a third embodiment,  FIG. 17A  is an external appearance plan view, and  FIG. 17B  is a cross-sectional view taken along line C-C′ in  FIG. 17A . 
         FIG. 18  is a flowchart illustrating the method of manufacturing the oscillator according to the third embodiment. 
         FIGS. 19A to 19C  are cross-sectional views illustrating a process of accommodating the oscillator according to the third embodiment. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. In addition, the following embodiments are not intended to limit the contents of the invention which are described in the appended claims. In addition, it cannot be said that all of configurations to be described later are indispensable constitutional requirements of the invention. 
     First Embodiment 
     1. Vibrator 
     First, description will be given of a vibrator that becomes an object for carrying out a method of manufacturing a vibrator (example of a vibration device) according to this embodiment with reference to the drawings.  FIG. 1A  is a cross-sectional view schematically illustrating a vibrator  5100  according to this embodiment.  FIG. 1B  is a plan view schematically illustrating the vibrator  5100  according to this embodiment. In addition,  FIG. 1A  is a cross-sectional view taken along line A-A in  FIG. 1B . 
     As illustrated in  FIGS. 1A and 1B , the vibrator  5100  includes a vibrator element  5102  and a package  5110 . Hereinafter, the vibrator element  5102  and the package  5110  will be described in detail. 
     (1) Vibrator Element 
       FIG. 2  is a perspective view schematically illustrating the vibrator element  5102 .  FIG. 3  is a plan view schematically illustrating the vibrator element  5102 .  FIG. 4  is a cross-sectional view schematically illustrating the vibrator element  5102  taken along line IV-IV in  FIG. 3 .  FIG. 5  is a cross-sectional view schematically illustrating the vibrator element  5102  taken along line V-V in  FIG. 3 . 
     As illustrated in  FIGS. 2 to 5 , the vibrator element  5102  includes a quartz crystal substrate  5010 , and excitation electrodes  5020   a  and  5020   b.    
     The quartz crystal substrate  5010  is constituted by an AT-cut quartz crystal substrate. Here,  FIG. 6  is a perspective view schematically illustrating an AT-cut quartz crystal substrate  5101 . 
     Typically, a piezoelectric material such as quartz crystal is a trigonal system, and has crystal axes (X, Y, Z) as illustrated in  FIG. 6 . The X axis represents an electrical axis, the Y axis represents a mechanical axis, and the Z axis represents an optical axis. A quartz crystal substrate  5101  is a flat plate of a so-called rotated Y-cut quartz crystal substrate in which an XZ plane (plane including the X axis and the Z axis) is cut from a piezoelectric material (for example, a synthetic quartz crystal) along a plane rotated around the X axis by an angle θ. In addition, the Y axis and the Z axis are also rotated around the X axis by the angle θ and are set to a Y′ axis and a Z′ axis, respectively. The quartz crystal substrate  5101  is a substrate in which a plane including the X axis and the Z′ axis is set as a main surface, and a direction along the Y′ axis is set as a thickness direction. Here, when θ is set to 35°15′, the quartz crystal substrate  5101  becomes the AT-cut quartz crystal substrate. Accordingly, in the AT-cut quartz crystal substrate  5101 , an XZ′ plane (plane including the X axis and the Z′ axis) orthogonal to the Y′ axis becomes a main surface (main surface of a vibration portion), and the AT-cut quartz crystal substrate  5101  can vibrate in a state in which thickness shear vibration is set as main vibration. The quartz crystal substrate  5010  can be obtained by processing the AT-cut quartz crystal substrate  5101 . 
     As illustrated in  FIG. 6 , the quartz crystal substrate  5010  is constituted by the AT-cut quartz crystal substrate  5101 . In the AT-cut quartz crystal substrate  5101 , the X axis of an orthogonal coordinate system including crystal axes of the quartz crystal such as the X axis set as the electrical axis, the Y axis set as the mechanical axis, and the Z axis set as the optical axis is set as a rotation axis, an axis, which is obtained by inclining the Z axis in such a manner that a +Z side is rotated in a −Y direction, is set as the Z′ axis, an axis, which is obtained by inclining the Y axis in such a manner that a +Y side is rotated in a +Z direction, is set as the Y′ axis, a plane including the X axis and the Z′ axis is set as a main surface, and a direction along the Y′ axis is set as a thickness direction. In addition, in  FIGS. 2 to 5 , and in  FIG. 7 , the X axis, the Y′ axis, and the Z′ axis which are orthogonal to each other are illustrated. 
     In addition, the quartz crystal substrate  5010  is not limited to the AT-cut quartz crystal substrate  5101 , and may be an SC-cut quartz crystal substrate in which thickness shear vibration is excited, and a piezoelectric substrate such as a BT-cut quartz crystal substrate that vibrates with different thickness shear vibration. 
     For example, the quartz crystal substrate  5010  has a rectangular shape in which the Y′ axis direction is set as a thickness direction, and the X axis direction is set as a long side and the Z′ axis direction is set as a short side in a plan view from the Y′ axis direction (hereinafter, simply referred to as “in a plan view”). The quartz crystal substrate  5010  includes a peripheral portion  5012  and a vibration portion  5014 . 
     The peripheral portion  5012  is provided at the periphery of the vibration portion  5014 . The peripheral portion  5012  is provided along an outer edge of the vibration portion  5014 . The peripheral portion  5012  has a thickness smaller than that of the vibration portion  5014 . 
     The vibration portion  5014  is surrounded by the peripheral portion  5012  in a plan view, and has a thickness larger than that of the peripheral portion  5012 . The vibration portion  5014  has a side along the X axis, and a side along the Z′ axis. Specifically, in a plan view, the vibration portion  5014  has a rectangular shape in which the X axis direction is set as the long side, and the Z′ axis direction is set as the short side. The vibration portion  5014  includes a first portion  5015  and a second portion  5016 . 
     The first portion  5015  of the vibration portion  5014  has a thickness larger than that of the second portion  5016 . In an example illustrated, the first portion  5015  is a portion having a thickness t 1 . In a plan view, the first portion  5015  has a square shape. 
     The second portion  5016  of the vibration portion  5014  has a thickness smaller than that of the first portion  5015 . In the example illustrated, the second portion  5016  is a portion having a thickness t 2 . The second portion  5016  is provided in the +X axis direction and the −X axis direction of the first portion  5015 , respectively. That is, the first portion  5015  is interposed between the second portions  5016  in the X axis direction. As described above, the vibration portion  5014  includes two kinds of portions  5015  and  5016  which have thicknesses different from each other, and the vibrator element  5102  has a two-step type mesa structure. 
     The vibration portion  5014  can vibrate in a state in which the thickness shear vibration is set as main vibration. Since the vibration portion  5014  has the two-step type mesa structure, the vibrator element  5102  can have an energy confinement effect. In addition, the “thickness shear vibration” represents vibration in which a displacement direction of the quartz crystal substrate is parallel to the main surface of the quartz crystal substrate (in the example illustrated, the displacement direction of the quartz crystal substrate is the X axis direction), and a propagation direction of waves is a plate thickness direction. 
     The vibration portion  5014  includes a first convex portion  5017  that further protrudes in the +Y′ axis direction in comparison to the peripheral portion  5012 , and a second convex portion  5018  that further protrudes in the −Y′ axis direction in comparison to the peripheral portion  5012 . For example, the convex portions  5017  and  5018  have the same shape and the same size. The convex portions  5017  and  5018  include the first portion  5015  and the second portion  5016 . 
     For example, as illustrated in  FIG. 5 , a lateral surface  5017   a  in the +X axis direction and a lateral surface  5017   b  in the −X axis direction in the first convex portion  5017 , and a lateral surface  5018   a  in the +X axis direction and a lateral surface  5018   b  in the -X axis direction in the second convex portion  5018  are provided with two step differences due to a difference between the thickness of the first portion  5015  and the thickness of the second portion  5016 , or a difference between the thickness of the second portion  5016  and the thickness of the peripheral portion  5012 . 
     For example, as illustrated in  FIG. 4 , a lateral surface  5017   c  of the first convex portion  5017  in the +Z′ axis direction is a surface that is perpendicular to a plane including the X axis and the Z′ axis. For example, a lateral surface  5017   d  of the first convex portion  5017  in the −Z′ axis direction is a surface that is inclined to the plane including the X axis and the Z′ axis. 
     For example, as illustrated in  FIG. 4 , a lateral surface  5018   c  of the second convex portion  5018  in the +Z′ axis direction is a surface that is inclined to the plane including the X axis and the Z′ axis. A lateral surface  5018   d  of the second convex portion  5018  in the −Z′ axis direction is a surface that is perpendicular to the plane including the X axis and the Z′ axis. 
     For example, in a case where the AT-cut quartz crystal substrate is etched by using a solution containing a hydrofluoric acid as an etchant, an m-plane of a quartz crystal is exposed, and thus the lateral surface  5017   d  of the first convex portion  5017  and the lateral surface  5018   c  of the second convex portion  5018  become surfaces which are inclined to the plane including the X axis and the Z′ axis. In addition, although not illustrated, a lateral surface of the quartz crystal substrate  5010  in the −Z′ direction other than the lateral surfaces  5017   d  and  5018   c  may be surfaces which are inclined with respect to the plane including the X axis and the Z′ axis through exposure of the m plane of the quartz crystal. 
     In addition, as illustrated in  FIG. 7 , the lateral surfaces  5017   d  and  5018   c  may be surfaces which are perpendicular to the plane including the X axis and the Z′ axis. For example, the lateral surfaces  5017   d  and  5018   c  may become surfaces which are perpendicular to the plane including the X axis and the Z′ axis by processing the AT-cut quartz crystal substrate with a laser, or by etching the AT-cut quartz crystal substrate through dry etching. In addition,  FIG. 2  illustrates a case where the lateral surfaces  5017   d  and  5018   c  are surfaces which are perpendicular to the plane including the X axis and the Z′ axis for convenience. 
     The first excitation electrode  5020   a  and the second excitation electrode  5020   b  are provided to overlap the vibration portion  5014  in a plan view. In the example illustrated, the excitation electrodes  5020   a  and  5020   b  are also further provided to the peripheral portion  5012 . For example, a planar shape (shape when seen in the Y′ axis direction) of the excitation electrodes  5020   a  and  5020   b  is a rectangular shape. The vibration portion  5014  is provided on an inner side of the outer edge of the excitation electrodes  5020   a  and  5020   b  in a plan view. That is, the area of the excitation electrodes  5020   a  and  5020   b  in a plan view is larger than that of the vibration portion  5014 . The excitation electrodes  5020   a  and  5020   b  are electrodes configured to apply a voltage to the vibration portion  5014 . 
     The first excitation electrode  5020   a  is connected to a first electrode pad  5024   a  through a first lead-out electrode  5022   a.  The second excitation electrode  5020   b  is connected to a second electrode pad  5024   b  through a second lead-out electrode  5022   b.  The electrode pads  5024   a  and  5024   b  are provided in the +X axis direction of the peripheral portion  5012 . As the excitation electrodes  5020   a  and  5020   b,  the lead-out electrodes  5022   a  and  5022   b,  and the electrode pads  5024   a  and  5024   b,  for example, electrodes, which are obtained by stacking chromium and gold from a quartz crystal substrate  5010  side in this order, may be used. 
     In addition, description has been given of an example in which the area of the excitation electrodes  5020   a  and  5020   b  is larger than that of the vibration portion  5014 , but the area of the excitation electrodes  5020   a  and  5020   b  in a plan view may be smaller than that of the vibration portion  5014 . In this case, the excitation electrodes  5020   a  and  5020   b  are provided on an inner side of the outer edge of the vibration portion  5014  in a plan view. 
     In addition, description has been given of the two-step type mesa structure in which the vibration portion  5014  includes two kinds of portions  5015  and  5016  which have thicknesses different from each other, but the number of steps of the mesa structure of the vibrator element  5102  is not particularly limited. For example, the vibrator element  5102  may be a three-step type mesa structure in which the vibration portion includes three kinds of portions which have thicknesses different from each other, or a one-step type mesa structure in which the vibration portion does not include portions having a different thickness. In addition, the vibrator element  5102  is not limited to the mesa type. For example, the quartz crystal substrate  5010  may have a uniform thickness, or may have a bevel structure or a convex structure. 
     In addition, description has been given of an example in which the lateral surfaces  5017   c  and  5017   d  of the first convex portion  5017 , and the lateral surfaces  5018   c  and  5018   d  of the second convex portion  5018  are not provided with a step difference due to a difference between the thickness of the first portion  5015  and the thickness of the second portion  5016 . However, in the vibrator element  5102 , a step difference may be provided in the lateral surfaces  5017   c,    5017   d,    5018   c,  and  5018   d.    
     In addition, description has been given of an example in which the first convex portion  5017  that further protrudes in the +Y′ axis direction in comparison to the peripheral portion  5012 , and the second convex portion  5018  that further protrudes in the −Y′ axis direction in comparison to the peripheral portion  5012  are provided, but the vibrator element  5102  may include any one of the convex portions. 
     (2) Package 
     As illustrated in  FIGS. 1A and 1B , the package  5110  includes a box-shaped base  5112  including a concave portion  5111  of which a top surface is opened, and a seal ring  5113  that is disposed on an upper end surface of the base  5112  that surrounds an opening of the concave portion  5111 , and a plate-shaped lead  5114  that is joined to the base  5112  so as to cover the opening of the concave portion  5111 . In addition, in  FIG. 1B , the lead  5114  and the seal ring  5113  are not illustrated for convenience. 
     The package  5110  has an accommodation space that is formed when the concave portion  5111  is covered with the lead  5114 , and the vibrator element  5102  is air-tightly accommodated and provided in the accommodation space. That is, the vibrator element  5102  is accommodated in the package  5110 . 
     In addition, for example, the inside of the accommodation space (the concave portion  5111 ), in which the vibrator element  5102  is accommodated, may be set to a decompressed state (vacuum state), or an inert gas such as nitrogen, helium, and argon may be sealed in the accommodation space. According to this, vibration characteristics of the vibrator element  5102  are improved. 
     For example, the material of the base  5112  may be various kinds of ceramic such as an aluminum oxide. For example, the material of the lead  5114  is a material having approximately the same linear expansion coefficient as that of the material of the base  5112 . Specifically, in a case where the material of the base  5112  is ceramic, the material of the lead  5114  is an alloy such as Kovar. 
     A first connection terminal  5130  and a second connection terminal  5132  are provided on the bottom surface of the concave portion  5111  of the package  5110 . The first connection terminal  5130  is provided to face the first electrode pad  5024   a  of the vibrator element  5102 . The second connection terminal  5132  is provided to face the second electrode pad  5024   b  of the vibrator element  5102 . The connection terminals  5130  and  5132  are electrically connected to the electrode pads  5024   a  and  5024   b,  respectively, through a conductive fixing member  5134 . 
     A first external terminal  5140  and a second external terminal  5142  are provided on the bottom surface of the package  5110 . For example, the first external terminal  5140  is provided at a position that overlaps the first connection terminal  5130  in a plan view. For example, the second external terminal  5142  is provided at a position that overlaps the second connection terminal  5132  in a plan view. The first external terminal  5140  is electrically connected to the first connection terminal  5130  through a via (not illustrated). The second external terminal  5142  is electrically connected to the second connection terminal  5132  through a via (not illustrated). 
     As the connection terminals  5130  and  5132 , and the external terminals  5140  and  5142 , for example, a metal film, in which respective films of nickel (Ni), gold (Au), silver (Ag), and copper (Cu) are stacked on a metallized layer (base layer) of chromium (Cr) and tungsten (W), is used. As the conductive fixing member  5134 , for example, solder, silver paste, a conductive adhesive (adhesive in which conductive filler such as a metal particle is dispersed in a resin material), and the like are used. 
     2. Method of Adjusting Frequency of Vibrator and Method of Manufacturing Vibrator 
     Next, description will be given of a method of adjusting a frequency of the vibrator according to this embodiment and a method of manufacturing the vibrator.  FIG. 8  is a flowchart illustrating an example of the method of manufacturing the vibrator according to this embodiment.  FIG. 9  is a cross-sectional view schematically illustrating processes of manufacturing the vibrator according to this embodiment. 
     The method of manufacturing the vibrator according to this embodiment includes the method of adjusting the frequency of the vibrator according to this embodiment. The method of manufacturing the vibrator according to this embodiment in  FIG. 8  includes a strong excitation process S 5 - 1  and a frequency adjustment process S 5 - 2  as the method of adjusting the frequency of the vibrator according to this embodiment. 
     First, as illustrated in  FIG. 9 , the vibrator element  5102  is mounted on the base  5112  (vibrator element mounting process (joining process) S 1 ). 
     Specifically, the vibrator element  5102  is fixed (joined) onto the connection terminals  5130  and  5132  which are provided to the base  5112  by using the conductive adhesive (joining member)  5134   a.    
     Then, the conductive adhesive  5134   a  is dried in a temperature atmosphere of a predetermined temperature (approximately 180° C.), thereby vaporizing a solvent of the conductive adhesive  5134   a.    
     Next, the conductive adhesive  5134   a  is subjected to a heating treatment (first annealing process S 2 ). 
     For example, the base  5112  on which the vibrator element  5102  is mounted is introduced into an annealing furnace (not illustrated), and annealing of the conductive adhesive  5134   a  is carried out at a peak heating temperature of approximately 200° C. to 300° C. In the first annealing process S 2 , for example, annealing for 4 hours, which includes heating for 2 hours at the peak heating temperature, is carried out. In the first annealing process S 2 , the conductive fixing member  5134  can be formed by curing the conductive adhesive  5134   a.    
     Here, in the first annealing process S 2 , annealing may be carried out in a vacuum atmosphere. When annealing is carried out in the vacuum atmosphere, it is possible to reduce the degree of oxidation of the excitation electrodes  5020   a  and  5020   b.  According to this, it is possible to suppress deterioration in aging characteristics. This is also true of a second annealing process S 4  and a third annealing process S 6  to be described later. 
     Next, the vibrator element  5102  and the conductive fixing member  5134  are cooled down to a predetermined temperature, and the annealing furnace is opened and ventilated (ventilation process S 3 ). 
     Next, the conductive fixing member  5134  and the vibrator element  5102  are subjected to a heating treatment (second annealing process S 4 ). 
     For example, the base  5112  on which the vibrator element  5102  is mounted is introduced into the annealing furnace, and a heating treatment is carried out with respect to the vibrator element  5102  and the conductive fixing member  5134 . For example, the second annealing process S 4  is carried out under the same temperature conditions and the same time conditions as in the first annealing process S 2 . In the second annealing process S 4 , discharging of an out-gas component in the conductive fixing member  5134  which is not sufficiently removed with the first annealing process S 2 , and removal of the out-gas component that is attached to the vibrator element  5102  are carried out, and stress distortion of the vibrator element  5102 , which is not completely solved in the first annealing process S 2 , can be reduced. 
     Next, power that is higher than drive power during use of the vibrator element  5102  is applied to the vibrator element  5102  so as to strongly excite the vibrator element  5102  (strong excitation process S 5 - 1 ). 
     Specifically, as illustrated in  FIG. 9 , power that is higher than power (drive power during typical operation) during use of the vibrator element  5102  is applied to the excitation electrodes  5020   a  and  5020   b  by using a synthesizer, an oscillation circuit for strong excitation, and the like in a state in which the vibrator element  5102  is mounted on the base  5112 , thereby strongly exciting the vibrator element  5102  (over-drive). For example, the drive power during use of the vibrator element  5102  is approximately 0.01 mWV. In the strong excitation process S 5 - 1 , power of 2.5 mW or more to 100 mW or less is applied to the vibrator element  5102 . More preferably, in the strong excitation process S 5 - 1 , power of 10 mW or more to 100 mW or less is applied to the vibrator element  5102 . For example, an application time is 1 second to 30 seconds. When the vibrator element  5102  is strongly excited as described above, it is possible to reduce equivalent series resistance of the vibrator element  5102 , that is, a so-called crystal impedance (CI) value, and thus it is possible to improve an oscillation rate in a frequency adjustment process S 5 - 2  (refer to “3. Experimental Example” to be described later). 
     Here, a drive level is power for oscillating the vibrator element  5102 , and is expressed by P=I 2 ×Re. In addition, I represents a current (effective value) that flows to the vibrator element, and Re represents equivalent series resistance of the vibrator element. The current I, which flows to the vibrator element, can be obtained by acquiring a waveform of a current flowing to the vibrator element by using an oscilloscope, and the like over the oscillation circuit. 
     Next, frequency adjustment of the vibrator element  5102  (vibrator  5100 ) is carried out (frequency adjustment process S 5 - 2 ). 
     For example, although not illustrated, a probe of a measurement device is brought into contact with the external terminals  5140  and  5142  which are electrically connected to the excitation electrodes  5020   a  and  5020   b,  a monitor electrode (not illustrated), and the like to excite the vibrator element  5102 , and an output frequency is measured. A drive level at this time is a drive level during typical use of the vibrator element. In addition, in a case where a frequency difference exists between an actual frequency that is measured, and a predetermined frequency, a part of the excitation electrodes  5020   a  and  5020   b  is etched (ion-milled) by irradiating the excitation electrodes  5020   a  and  5020   b  with an ion laser and the like to reduce a mass, thereby carrying out the frequency adjustment. In addition, the frequency adjustment may be carried out by forming a film on the excitation electrodes  5020   a  and  5020   b  so as to increase a mass. 
     Next, the conductive fixing member  5134  and the vibrator element  5102  are subjected to a heating treatment (third annealing process S 6 ). 
     For example, the base  5112  on which the vibrator element  5102  is mounted is introduced into an annealing furnace, and a heating treatment is carried out with respect to the vibrator element  5102  and the conductive fixing member  5134 . For example, in the third annealing process S 6 , annealing including heating for 45 minutes at a peak heating temperature of approximately 200° C. to 300° C. is carried out. 
     According to the third annealing process S 6 , discharging of the out-gas component in the conductive fixing member  5134  which is not sufficiently removed with the first annealing process S 2  and the second annealing process S 4 , and removal of the out-gas component that is attached to the vibrator element  5102  are carried out, and stress distortion of the vibrator element  5102 , which is not completely solved in the first annealing process S 2  and the second annealing process S 4 , can be reduced. In addition, it is possible to reduce stress distortion of the vibrator element  5102  which is newly added in the frequency adjustment process S 5 - 2 . 
     In addition, the third annealing process S 6  may not be carried out. 
     Next, as illustrated in  FIG. 1A , the lead  5114  is joined to the base  5112 , and the concave portion  5111  of the base  5112  is sealed (sealing process S 7 ). According to this, it is possible to accommodate the vibrator element  5102  in the accommodation space (concave portion  5111 ) of the package  5110 . The joining between the base  5112  and the lead  5114  is carried out in such a manner that the lead  5114  is placed on the seal ring  5113 , and the seal ring  5113  is welded to the base  5112  by using, for example, a resistance welder. In addition, the joining between the base  5112  and the lead  5114  is not particularly limited, and may be carried out by using an adhesive, or may be carried out through seam welding. 
     Next, characteristics of the vibrator  5100  are inspected (inspection process S 8 ). 
     For example, although not illustrated, characteristics (drive level dependence (DLD) characteristics and the like) of the vibrator  5100  are measured by bringing a probe of a measurement device into contact with the external terminals  5140  and  5142  which are electrically connected to the excitation electrodes  5020   a  and  5020   b,  a monitor electrode (not illustrated), and the like. 
     Through the above-described processes, it is possible to manufacture the vibrator  5100 . 
     For example, the method of adjusting the frequency of the vibrator  5100  according to this embodiment has the following characteristics. 
     The method of adjusting the frequency of the vibrator  5100  according to this embodiment includes the process S 5 - 1  of strongly exciting the vibrator element  5102  by applying power that is higher than drive power during use of the vibrator element  5102  to the vibrator element  5102 , and the process S 5 - 2  of adjusting the frequency of the vibrator element  5102  after the process S 5 - 1  of strongly exciting the vibrator element  5102 . According to this, it is possible to reduce the CI value of the vibrator element  5102 , and thus it is possible to improve the oscillation rate in the frequency adjustment process S 5 - 2  (refer to “3. Experimental Example” to be described later). Accordingly, it is possible to improve a yield ratio during manufacturing of the vibrator  5100 . 
     In the method of adjusting the frequency of the vibrator  5100  according to this embodiment, in the process S 5 - 1  of strongly exciting the vibrator element  5102 , power of 2.5 mW or more to 100 mW or less is applied to the vibrator element  5102 . According to this, it is possible to reduce the CI value of the vibrator element  5102 , and thus it is possible to improve the oscillation rate (refer to “3. Experimental Example” to be described later). 
     In the method of adjusting the frequency of the vibrator  5100  according to this embodiment, in the process S 5 - 1  of strongly exciting the vibrator element  5102 , power of 10 mW or more to 100 mW or less is applied to the vibrator element  5102 . According to this, it is possible to further reduce the CI value of the vibrator element  5102 , and thus it is possible to further improve the oscillation rate (refer to “3. Experimental Example” to be described later). 
     The method of manufacturing the vibrator  5100  according to this embodiment includes the method of adjusting the frequency of the vibrator  5100  according to this embodiment, and thus it is possible to improve a yield ratio during manufacturing. 
     3. Experimental Example 
     Hereinafter, an experimental example will be described, and the invention will be described in more detail. In addition, the invention is not particularly limited by the following experimental example. 
     3.1 First Experimental Example 
     With regard to the method of manufacturing the vibrator  5100  described above, an experiment was carried out to investigate a relationship between the drive level during over-drive, and a variation ratio of the CI value before and after the over-drive. 
     Specifically, in the method of manufacturing the vibrator  5100  described above, the CI value before and after the over-drive was measured with respect to cases where the drive level DL during the over-drive in the strong excitation process S 5 - 1  was 0.1 mW, 0.5 mW, 2.5 mW, 10 mW, and 100 mW, respectively. In addition, the vibrator was set to the AT-cut type vibrator, and an oscillation frequency was set to 16 MHz. 
     A method of obtaining the variation ratio of the CI value before and after the over-drive will be described in more detail. Here, description will be given of a case where DL is 0.1 mW as an example. First, in the method of manufacturing the vibrator  5100  as described above, a drive level DL of 0.01 mW during typical use was applied to the vibrator element before the strong excitation process S 5 - 1  so as to measure the CI value. Next, in the strong excitation process S 5 - 1 , power in a drive level DL of 0.1 mW was applied for 1 second to 30 seconds, thereby strongly exciting the vibrator  5100  (over-drive). Next, a drive level DL of 0.01 mW during typical use was applied again to the vibrator element so as to measure the CI value. In this manner, a variation ratio of the CI value before and after the over-drive was obtained with respect to the case where DL was set to 0.1 mW. 
     The CI value before and after the over-drive was also measured with respect to other cases where the drive level DL was set to 0.5 mW, 2.5 mW, 10 mW, and 100 mW, respectively by the same method so as to obtain the variation ratio of the CI value before and after the over-drive. 
     In addition, for reference, the CI value was also measured with respect to a case where the drive level DL in the strong excitation process S 5 - 1  was set to 0.01 mW, that is, a case where a drive level during typical use was applied without the strong excitation. 
       FIG. 10  is a graph illustrating a relationship between the drive level DL during over-drive, and a variation ratio ((CI2−CI1)/CI1) of a CI value (CI2) after the over-drive to a CI value (CI1) before the over-drive. 
     As illustrated in  FIG. 10 , the CI value of the vibrator element after the carrying out the over-drive by applying a drive level DL of 2.5 mW or greater was greatly reduced in comparison to the CI value before carrying out the over-drive. Specifically, after carrying out the over-drive by applying DL of 2.5 mW, the CI value was reduced by 40%. In addition, after carrying out the over-drive by applying DL of 10 mW, the CI value was reduced by 45%. In addition, after carrying out the over-drive by applying DL of 100 mW, the CI value was reduced by 50%. As described above, when the over-drive was carried out by applying a drive level DL as high as 2.5 mW or greater, it could be seen that it enters a state in which the vibrator element is likely to oscillate. 
     3.2 Second Experimental Example 
     Next, in the method of manufacturing the vibrator  5100  as described above, an experiment of investigating a relationship between the drive level during the over-drive and an oscillation rate after the over-drive was carried out. 
     Specifically, as is the case with the above-described first experimental example, an oscillation rate was measured with respect to cases where the drive level DL during the over-drive in the strong excitation process S 5 - 1  was set to 0.1 mW, 0.5 mW, 2.5 mW, 10 mW, and 100 mW, respectively. In addition, the vibrator was set to an AT-cut type vibrator, and an oscillation frequency was set to 16 MHz. 
     In addition, the oscillation rate represents a ratio of normally oscillating vibrator elements to the total measurement number. In addition, the normally oscillating vibrator elements represent vibrator elements in which the CI value at DL of 0.01 mW satisfies negative resistance of an oscillation circuit. Here, an investigation was made whether or not 1000 vibrator elements normally oscillate for each drive level DL. 
       FIG. 11  is a graph illustrating a relationship between the drive level DL during the over-drive, and the oscillation rate after the over-drive. 
     As illustrated in  FIG. 11 , in a case of a drive level DL of 0.01 mW, that is, in a case of not carrying out the over-drive, the oscillation rate was approximately 93%, but in a case of carrying out the over-drive at a drive level DL of 2.5 mW or greater, the oscillation rate becomes 100%. 
     In addition, in the over-drive in which a drive level DL of 100 mW was applied to the vibrator element, as described above, the CI value was reduced by 50%, and the oscillation rate became 100%, and thus a sufficient effect was obtained. According to this, it is preferable that the over-drive is carried out in a drive level of 100 mW or less so as to realize low power consumption. 
     In addition, when the method of manufacturing the vibrator as described above includes a vibrator formation process of forming the vibrator element  5102  before the vibrator element mounting process S 1 , and a joining process of connecting a semiconductor device  700  to be described later to the base  5112  at a position not interfering with the vibrator element  5102  through a joining member  510  to be described later before the sealing process S 7 , the above-described method becomes a method of manufacturing an oscillator. 
     According to this, the method of manufacturing the oscillator as described above includes a vibrator element formation process of forming the vibrator element  5102 , a joining process of joining the base  5112  and the vibrator element  5102  through a joining member (conductive adhesive  5134   a ) (vibrator element mounting process S 1 ), a strong excitation process of applying power, which is higher than drive power during use of the vibrator element  5102 , to the vibrator element  5102  (strong excitation process S 5 - 1 ), and a joining process of connecting the semiconductor device  700  to the base  5112  through the joining member  510 . 
     In the method of manufacturing the oscillator as described above, as is the case with the method of manufacturing the vibrator, it is possible to reduce the CI value of the vibrator element  5102 , and thus it is possible to improve a yield ratio during manufacturing. 
     Second Embodiment 
       FIGS. 12A and 12B  illustrate a schematic configuration of a vibrator that is obtained by the method of manufacturing the vibrator (example of a vibration device) according to the second embodiment.  FIG. 12A  is an external appearance plan view in which a lead is omitted, and  FIG. 12B  is a cross-sectional view taken along line A-A′ in  FIG. 12A . 
     As illustrated in  FIG. 12B , a vibrator  1000  illustrated in  FIGS. 12A and 12B  includes a vibrator element  100 , a package (corresponding to the base in the first embodiment)  200  having a concave portion space  200   a  capable of accommodating the vibrator element  100 , a lead  300 , and a seal member  400  that joins the package  200  and the lead  300  so as to tightly seal the concave portion space  200   a.    
     The vibrator element  100  includes a piezoelectric element  10 , a first electrode  21  that is formed on a first main surface  10   a  of the piezoelectric element  10 , and a second electrode  22  that is formed on a second main surface  10   b  of the piezoelectric element  10 . With regard to the piezoelectric element  10 , there is no particular limitation as long as the piezoelectric element  10  is formed from a material such as quartz crystal, ceramic, and PZT which have piezoelectric properties, and in this embodiment, description will be made with reference to the quartz crystal. Hereinafter, the piezoelectric element  10  is referred to as a quartz crystal element  10 . 
     As illustrated in  FIG. 12A , the first electrode  21  includes an excitation electrode  21   a  which is formed on the first main surface  10   a  and has an approximately rectangular planar shape in this embodiment, a connection electrode  21   b  that is formed on the second main surface  10   b  that is a rear surface of the first main surface  10   a,  and an extension portion  21   c  that connects the excitation electrode  21   a  and the connection electrode  21   b.  In addition, the second electrode  22  includes an excitation electrode  22   a  which is formed on the second main surface  10   b  and has an approximately rectangular planar shape in this embodiment to overlap the excitation electrode  21   a  which is formed on the first main surface  10   a  in a plan view, a connection electrode  22   b,  and an extension portion  22   c  that connects the excitation electrode  22   a  and the connection electrode  22   b.    
     The package  200  has insulating properties. For example, the package  200  is formed from ceramic, a resin, glass, and the like. Connection electrodes  610  are formed on the bottom  200   b  of the concave portion space  200   a  of the package  200 , and external connection electrodes  620   a  and  620   b,  which are electrically connected to the connection electrodes  610  through an interconnection (not illustrated) formed on an inner side of the package  200 , are formed on an external bottom surface  200   c  of the package  200 . 
     In the vibrator element  100 , the connection electrodes  21   b  and  22   b  are arranged in the concave portion space  200   a  of the package  200  to face the connection electrodes  610  and are connected thereto by a joining member  500  having conductivity. In addition, the lead  300  is fixed to an upper end surface  200   d  having a frame-shaped planar shape on an opening side of the concave portion space  200   a  of the package  200  through the seal member  400 , and thus the concave portion space  200   a  is air-tightly sealed. In addition, for example, it is preferable that the concave portion space  200   a  is, for example, vacuum-sealed or filled with an inert gas, and is air-tightly sealed. 
     As described above, as the vibrator element  100  that is provided to the vibrator  1000  according to this embodiment, as illustrated in  FIGS. 12A and 12B , a so-called AT vibrator element is exemplified, but there is no limitation thereto, and the vibrator element  100  may be, for example, a tuning fork type vibrator element and the like, or a gyro element. 
       FIGS. 13A to 13C  are flowcharts illustrating a method of manufacturing the vibrator  1000  as described above.  FIG. 13A  illustrates a method of manufacturing a vibrator according to the second embodiment,  FIG. 13B  illustrates details of a strong excitation process (S 20 ) illustrated in  FIG. 13A , and  FIG. 13C  is a flowchart illustrating details of an accommodation process (S 40 ) illustrated in  FIG. 13A . 
     As illustrated in  FIG. 13A , the method of manufacturing the vibrator  1000  according to this embodiment starts from a vibrator element forming process (S 10 ). 
     Vibrator Element Forming Process 
     As illustrated in  FIG. 14A , in the vibrator element forming process (S 10 ), a disc like quartz crystal substrate  2000  (example of a substrate) having a predetermined thickness, that is, a so-called quartz crystal wafer is prepared. Hereinafter, the quartz crystal substrate  2000  is referred to as a wafer  2000 . 
     As illustrated in  FIG. 14B  that is an enlarged view of a B portion illustrated in  FIG. 14A , for example, a plurality of penetration portions  2010   a  are formed in the wafer  2000  through patterning and etching by photolithography. When the penetration portions  2010   a  are formed, a vibration element wafer  2010 , in which a plurality of quartz crystal element portions  2010   b,  and a plurality of breaking-off portions  2010   c  as connection portions with the wafer  2000 , is obtained. 
     The vibrator element forming process (S 10 ) is carried out to obtain a first vibrator element wafer  2020  including a plurality of first vibrator element portions  2110 . In the vibrator element forming process (S 10 ), a conductive metal film is formed on a surface of the vibration element wafer  2010  through deposition or sputtering, and as illustrated in  FIG. 14C , the first electrode  21  is formed on one surface of each of the quartz crystal element portions  2010   b  which are formed in the vibration element wafer  2010  through patterning and etching by photolithography. In addition, as illustrated in  FIG. 14D , the second electrode  22  and the connection electrode  21   b  of the first electrode  21  are formed on the other surface of the quartz crystal element portion  2010   b.    
     Strong Excitation Process 
     As illustrated in  FIGS. 14C and 14D , the first vibrator element wafer  2020 , which is obtained by the vibrator element forming process (S 10 ) and includes the plurality of first vibrator element portions  2110  in which the first electrode  21  and the second electrode  22  are formed, is subjected to the strong excitation process (S 20 ). As illustrated in  FIG. 13B , the strong excitation process (S 20 ) includes a power application process (S 21 ), an inspection process (S 22 ), and a defective product removal process (S 23 ). 
     Power Application Process 
     First, as illustrated in  FIG. 15A , in the power application process (S 21 ), connection terminals  3200   a  and  3200   b,  which are connected to a strong excitation control unit  3100  provided to a strong excitation device  3000 , are brought into contact with the connection electrodes  21   b  and  22   b , respectively, and predetermined large power is applied to the first electrode  21  and the second electrode  22  by the strong excitation control unit  3100 . In addition, vibration with a large amplitude is excited in each of the first vibrator element portions  2110  due to large power supplied to the excitation electrodes  21   a  and  22   a,  and thus at least a part of foreign matter adhered to the first electrode  21  and the second electrode  22  is shaken off. In addition, it is possible to improve adhesiveness between the quartz crystal element  10  and the electrodes  21  and  22 . 
     After applying the predetermined large power is applied to the first vibrator element portion  2110  for predetermined time, the connection terminals  3200   a  and  3200   b  are separated from the connection electrodes  21   b  and  22   b . According to this, the power application process (S 21 ) with respect to the first vibrator element portion  2110  is terminated, and a second vibrator element portion  2120  is formed. Then, the connection terminals  3200   a  and  3200   b  are moved to a next one of the first vibrator element portions  2110 , and the power application process (S 21 ) is carried out. In this manner, the power application process (S 21 ) is sequentially carried out with respect to the entirety of the first vibrator element portions  2110  which are provided to the first vibrator element wafer  2020 , thereby obtaining a second vibrator element wafer  2021  including a plurality of the second vibrator element portions  2120 . Then, the process transitions to the inspection process (S 22 ). 
     Inspection Process 
     Since occurrence of breakage is predicted in a part of the second vibrator element portion  2120  due to application of power, which is higher than predetermined operation power of the second vibrator element portions  2120 , in the power application process (S 21 ), the inspection process (S 22 ) inspects whether or not a predetermined operation is obtained. Although not illustrated, in the inspection process (S 22 ), inspection terminals, which are connected to an inspection device, are brought into contact with the connection electrodes  21   b  and  22   b  to apply predetermined power to the connection electrodes  21   b  and  22   b,  thereby causing excitation. From an oscillation signal that is obtained, a predetermined quality, for example, a frequency equivalent series resistance value and the like are detected to determine whether or not the quality is good or bad. 
     Defective Product Removal Process 
     The second vibrator element wafer  2021 , of which the individual second vibrator element portions  2120  are subjected to the quality determination in the inspection process (S 22 ), is subjected to the defective product removal process (S 23 ). As illustrated in  FIG. 15B , in the defective product removal process (S 23 ), a defective vibrator element portion  2120 F, which is determined as a bad quality, is cut out from a cut-out portion  2010   c,  and is removed from the second vibrator element wafer  2021 . When the defective vibrator element portion  2120 F is determined as a bad quality in the above-described inspection process (S 22 ), position information of the defective vibrator element portion  2120 F of the second vibrator element wafer  2021  in the vibrator element wafer  2020  is stored in an inspection device (not illustrated), and a pressing force F in an illustrated arrow direction is applied by a pressing unit (not illustrated). A cut-out portion  2010   c  with the weakest strength in the detective vibrator element portion  2120 F, to which the pressing force F is applied, is fractured, and thus the defective vibrator element portion  2120 F is detached and removed from the second vibrator element wafer  2021 . In addition, in the detective product removal process, a mark that is recognizable with an image recognition method may be formed on a surface of the detective vibrator element portion  2120 F by using ink, a laser, and the like instead of removing the defective vibrator element portion  2120 F from the second vibrator element wafer  2021 . 
     As described above, the strong excitation process (S 20 ) including the power application process (S 21 ), the inspection process (S 22 ), and the defective product removal process (S 23 ) is carried out, and a second vibrator element wafer  2022 , in which a plurality of the second vibrator element portions  2120  with a good quality are formed, is subjected to the subsequent individual piece division process (S 30 ). 
     Individual Piece Division Process 
     As is the case with the above-described defective product removal process (S 23 ), the individual piece division process (S 30 ) is a process of applying a pressing force F to each of the second vibrator element portions  2120  to fracture the cut-out portion  2010   c  from the second vibrator element wafer  2022  including the second vibrator element portions  2120  with a good quality, thereby taking out individual pieces of the vibrator elements  100 . Each of the vibrator elements  100 , which are divided into individual pieces in the individual piece division process (S 30 ), is subjected to the accommodation process (S 40 ). In addition, in a case where a mark that is recognizable with an image recognition method is formed on the surface of the detective vibrator element portion  2120 F by using ink, a laser, and the like in the defective product removal process (S 23 ), image recognition is carried out in the process of division into individual pieces, and the defective vibrator element portion  2120 F is not taken out. 
     Accommodation Process 
     The accommodation process (S 40 ) is a process of obtaining the vibrator  1000  (refer to  FIGS. 12A and 12B ) through so-called packaging. The accommodation process (S 40 ) includes a mounting process (S 41 ), a frequency adjustment process (S 42 ), and a sealing process (S 43 ).  FIGS. 16A to 16C  illustrate a manufacturing process that is the accommodation process (S 40 ), and cross-sectional views of a portion taken along line A-A′ in  FIG. 12A . The same reference numerals will be given to the same constituent elements as in the vibrator  1000  illustrated in  FIGS. 12A and 12B , and description thereof will not be repeated. 
     Mounting Process 
     In the accommodation process (S 40 ), first, mounting process (S 41 ) is carried out. As illustrated in  FIG. 16A , in the mounting process (S 41 ), the joining member  500  having conductivity is arranged on each of the connection electrodes  610  which are formed on the bottom  200   b  of the concave portion space  200   a  of the package  200 . In addition, the vibrator element  100  is disposed in the concave portion space  200   a  in such a manner that each of the connection electrodes  21   b  and  22   b  of the vibrator element  100  is placed on the joining member  500  on each of the connection electrode  610  so as to face the connection electrode  610 . Then, when the joining member  500  is cured to electrically connect each of the connection electrodes  610  and each of the connection electrodes  21   b  and  22   b  of the vibrator element  100 , and to fix the vibrator element  100  to the package  200 , the mounting process (S 41 ) is terminated. In addition, the joining member  500  is not particularly limited and examples thereof include a conductive adhesive, solder, a metal bump, and the like. Among these, the conductive adhesive with high productivity is appropriately used. 
     Frequency Adjustment Process 
     When the vibrator element  100  is mounted in the concave portion space  200   a  of the package  200  through the mounting process (S 41 ), the process transitions to the frequency adjustment process (S 42 ). As illustrated in  FIG. 16B , in the frequency adjustment process (S 42 ), a laser L is emitted from a laser irradiation device (not illustrated) toward the excitation electrode  21   a  of the first electrode  21  in a direction from an opening side of the concave portion space  200   a  of the package  200 , and a part of an electrode metal of the excitation electrode  21   a  transpires and is removed due to the laser L before reaching a predetermined vibration frequency. In addition, in addition to the above-described method, the frequency adjustment process (S 42 ) may be carried out by irradiating the excitation electrode  21   a  with ions, plasma, and the like, or may be carried out by applying a member such as Au, Ag, and Al to the excitation electrode  21   a  by a method such as deposition and sputtering. 
     Sealing Process 
     The package  200 , on which the vibrator element  100  adjusted to a predetermined frequency through the frequency adjustment process (S 42 ) is mounted, is subjected to the sealing process (S 43 ). As illustrated in  FIG. 16C , in the sealing process (S 43 ), first, the seal member  400  is placed on the upper end surface  200   d,  which has a frame-shaped planar shape, on an opening side of the concave portion space  200   a  of the package  200 , and the lead  300  is further placed on the seal member  400 . In addition, as the seal member  400 , a material having a thermal expansion coefficient close to that of the package  200 , for example, Kovar is appropriately used. In addition, as the lead  300 , for example, Kovar having a thermal expansion coefficient close to that of the package  200  and the seal member  400  is appropriately used. In addition, as the package  200 , a package in which the seal member  400  is placed on the upper end surface  200   d  in advance may be used. 
     In addition, in a processing room (chamber) (not illustrated) which is maintained to a vacuum environment or an inert gas atmosphere environment, the lead  300  and the package  200  are air-tightly joined by a joining method such as seam welding. In this state, the sealing process (S 43 ) is terminated, the accommodation process (S 40 ) is terminated, and the vibrator  1000  is obtained. Then, the process transitions to the inspection process (S 50 ). 
     Inspection Process 
     In the inspection process (S 50 ), inspection is carried out on the basis of predetermined specifications of the vibrator  1000  as a finished product. Although not illustrated, in the inspection process (S 50 ), predetermined functional quality inspection, which is carried out by bringing terminals provided to an inspection device into contact with the external connection electrodes  620   a  and  620   b,  external appearance inspection with the naked eye or a microscope, and the like are carried out for quality determination. 
     With regard to a vibrator in the related art, there is also known a method of carrying out strong excitation, that is, so-called over-drive to improve adhesiveness between an excitation electrode and an element piece, but the strong excitation is typically carried out after sealing a vibrator element in a package. According to this method in the related art, foreign matter adhered to the vibrator element are shaken off into a sealed package inner space due to strong excitation, and thus the foreign matter collected in the package inner space are repetitively adhered to and detached from the vibrator element. Therefore, the repetitive adhesion and detachment become a cause for a variation in vibration characteristics of the vibrator element. 
     However, in the method of manufacturing the vibrator  1000  according to the second embodiment, the strong excitation process (S 20 ) is carried out in a state of the vibrator element wafer  2020 , and thus at least a part of foreign matter adhered to the vibrator element  100  is shaken off. According to this, it is possible to reduce a possibility that the foreign matter adhered to the vibrator element  100  are introduced into the package  200 . Accordingly, it is possible to obtain the vibrator  1000  having stable vibration characteristics. In addition, when the strong excitation process (S 20 ) of the second embodiment is carried out under the same conditions as in the strong excitation process (S 5 - 1 ) of the first embodiment, the same effect as in the first embodiment is obtained. 
     Third Embodiment 
       FIGS. 17A and 17B  illustrate a schematic configuration of an oscillator that is obtained by a method of manufacturing an oscillator (example of the vibration device) according to a third embodiment.  FIG. 17A  is an external appearance plan view in which the lead is omitted, and  FIG. 17B  is a cross-sectional view taken along line C-C′ in  FIG. 17A . An oscillator  1100  illustrated in  FIG. 17  includes the vibrator element  100  provided to the vibrator  1000  according to the second embodiment, and a semiconductor device including an oscillation circuit of the vibrator element  100 , and thus the same reference numerals will be given to the same constituent elements in the vibrator  1000  according to the second embodiment and the manufacturing method thereof, and description thereof will not be repeated. 
     As illustrated in  FIG. 17B , the oscillator  1100  illustrated in  FIGS. 17A and 17B  includes a vibrator element  100 , a semiconductor device  700  (hereinafter, referred to as “IC  700 ”), a package (base)  210  including a first concave portion space  210   a  capable of accommodating the IC  700 , and a second concave portion space  210   b  which is connected to the first concave portion space  210   a  and is capable of accommodating the vibrator element  100 , a lead  300 , and a seal member  400  which joins the package  210  and the lead  300 , thereby closely sealing the concave portion spaces  210   a  and  210   b.    
     The IC  700  includes an external electrode  700   b  which is formed on one surface  700   a  of the IC  700  and is electrically connected to an electronic circuit (not illustrated) that is formed inside the IC  700 . The external electrode  700   b  is disposed over an IC connection electrode  612 , which is formed on the bottom  210   d  of the first concave portion space  210   a  of the package  210 , to face the external electrode  700   b  of the IC  700 , and is joined to the external electrode  700   b  through a joining member  510  having conductivity. According to this, the IC  700  is accommodated in the first concave portion space  210   a  of the package  210 . 
     With regard to the vibrator element  100 , each of connection electrodes  21   b  and  22   b  is arranged to face each of connection electrodes  611  which are formed on a stepped portion  210   c  that becomes the bottom of the second concave portion space  210   b  of the package  210 , and is fixed and arranged by the joining member  500  having conductivity. In addition, the connection electrode  611  and the IC connection electrode  612  are electrically connected through an arrangement interconnection (not illustrated) that is formed inside the package  210 . In addition, the IC connection electrode  612  is electrically connected to external connection electrodes  620   a  and  620   b , which are formed on an external bottom surface  210   e  of the package  210 , through an arrangement interconnection (not illustrated) that is formed inside the package  210 . 
     Next, description will be given of a method of manufacturing the oscillator  1100 . The method of manufacturing the oscillator  1100  according to this embodiment includes the same processes in the method of manufacturing the vibrator  1000  according to the second embodiment, that is, the same processes as in the flowchart illustrated in  FIGS. 13A to 13C . However, a configuration of the mounting process (S 41 ) included in the accommodation process (S 40 ) illustrated in  FIG. 13C  is different in each case, and  FIG. 18  illustrates a flowchart of a process that is included in the mounting process (S 41 ). In addition, as described above, in the method of manufacturing the oscillator  1100  according to the third embodiment, description of the same processes as in the method of manufacturing the vibrator  1000  according to the second embodiment will not be repeated. 
     From Vibrator Element Forming Process to Individual Piece Division Process 
     The oscillator  1100 , which is obtained by the manufacturing method according to this embodiment, includes the vibrator element  100  that is provided to the vibrator  1000  that is obtained by the manufacturing method according to the second embodiment. Accordingly, processes from the vibrator element forming process (S 10 ) to the individual piece division process (S 30 ) are the same between the second embodiment and the third embodiment illustrated in  FIG. 13A . Accordingly, description thereof will not be repeated. 
     Accommodation Process 
     An accommodation process (S 40 ) is a process of obtaining the oscillator  1100  (refer to  FIGS. 17A and 17B ) through so-called packaging. The accommodation process (S 40 ) includes a mounting process (joining process) (S 41 ), a frequency adjustment process (S 42 ), and a sealing process (S 43 ). In addition, the mounting process (S 41 ) includes an IC mounting process (S 411 ), and a vibrator element mounting process (S 412 ).  FIGS. 19A to 19C  are cross-sectional views of a portion taken along line C-C′ in  FIG. 17A  which illustrates the manufacturing process of the mounting process (S 41 ) included in the accommodation process (S 40 ). The same reference numerals will be given to the same constituent elements as in the oscillator  1100  illustrated in  FIGS. 17A and 17B , and description thereof will not be repeated. 
     IC Mounting Process 
     In the mounting process (S 41 ), first, the IC mounting process (S 411 ) is carried out. As illustrated in  FIG. 19A , in the IC mounting process (S 411 ), a joining member  510  having conductivity is arranged in advance on the IC connection electrode  612  that is formed on the bottom  210   d  of the first concave portion space  210   a  of the package  210 , and the external electrode  700   b  of the IC  700 , which is prepared in advance, is placed on the joining member  510  to face the IC connection electrode  612 . Then, when the joining member  510  is cured to electrically connect the IC connection electrode  612  and the external electrode  700   b  of the IC  700  to each other, and to fix the IC  700  to the package  210 , the IC mounting process (S 411 ) is terminated. In addition, in the IC mounting process (S 411 ), the IC connection electrode  612  and the external electrode  700   b  may be electrically connected to each other by arranging the joining member  510  on the external electrode  700   b  of the IC  700 , and joining the joining member  510  and the IC connection electrode  612  to each other. In addition, in addition to the above-described method, after disposing the IC  700  in such a manner that a surface on which the external electrode  700   b  is not formed, and the bottom  210   d  of the first concave portion space  210   a  of the package  210  face each other, the external electrode  700   b  and the IC connection electrode  612  may be electrically connected to each other through a bonding wire. 
     Vibrator Element Mounting Process 
     After the IC mounting process (S 411 ), the process transitions to the vibrator element mounting process (S 412 ). As illustrated in  FIG. 19B , in the vibrator element mounting process (S 412 ), first, the joining member  500  having conductivity is arranged on the connection electrode  611  that is formed on the stepped portion  210   c  that becomes the bottom of the second concave portion space  210   b  of the package  210 . Next, the vibrator element  100  is accommodated in the second concave portion space  210   b  in such a manner that each of the connection electrodes  21   b  and  22   b  which are provided to the vibrator element  100  faces each of the connection electrodes  611 , and the vibrator element  100  is placed on the stepped portion  210   c  in such a manner that each of the connection electrodes  21   b  and  22   b  comes into contact with the joining member  500 . Then, when the joining member  500  is cured to electrically connect each of the connection electrodes  611  and each of the connection electrodes  21   b  and  22   b  of the vibrator element  100 , and to fix the vibrator element  100  to the package  210 , the vibrator element mounting process (S 412 ) is terminated. 
     After carrying out the mounting process (S 41 ) including the IC mounting process (S 411 ) and the vibrator element mounting process (S 412 ), the process transitions to the frequency adjustment process (S 42 ). 
     Frequency Adjustment Process and Sealing Process 
     The frequency adjustment process (S 42 ) and the sealing process (S 43 ) are the same as in the method of manufacturing the vibrator  1000  according to the second embodiment. As illustrated in  FIG. 19B , in the frequency adjustment process (S 42 ) according to this embodiment, the excitation electrode  21   a  of the first electrode  21  of the vibrator element  100 , which is accommodated in the package  210 , is irradiated with a laser L to transpire and remove a part of the excitation electrode  21   a.  According to this, the vibrator element  100  is adjusted to a predetermined frequency. 
     After the frequency adjustment process (S 42 ), the process transitions to the sealing process (S 43 ). As illustrated in  FIG. 19C , in the sealing process (S 43 ), first, the seal member  400  is placed on an upper end surface  210   f  having a frame-shaped planar shape on an opening side of the second concave portion space  210   b  of the package  210 , and the lead  300  is further placed on the seal member  400 . In addition, in a processing room (chamber) (not illustrated) which is maintained to a vacuum environment or an inert gas atmosphere environment, the lead  300  and the package  210  are air-tightly joined by a joining method such as seam welding. In this state, the sealing process (S 43 ) is terminated, and the oscillator  1100  is obtained. Then, the process transitions to an inspection process (S 50 ). 
     Inspection Process 
     After the accommodation process (S 40 ) including the mounting process (S 41 ), the frequency adjustment process (S 42 ), and the sealing process (S 43 ), the process transitions to the inspection process (S 50 ). In the inspection process (S 50 ), inspection is carried out on the basis of predetermined specifications of the oscillator  1100  as a finished product. Although not illustrated, in the inspection process (S 50 ), predetermined functional quality inspection, which is carried out by bringing terminals provided to an inspection device into contact with the external connection electrodes  620   a  and  620   b , external appearance inspection with the naked eye or a microscope, and the like are carried out for quality determination. 
     In the method of manufacturing the oscillator  1100  according to the third embodiment as described above, the strong excitation process (S 20 ) is carried out in a state of the vibrator element wafer  2020 , and thus at least a part of foreign matter adhered to the vibrator element  100  is shaken off. According to this, it is possible to reduce a possibility that the foreign matter adhered to the vibrator element  100  are introduced into the package  210 . Accordingly, it is possible to obtain the oscillator  1100  having stable vibration characteristics. 
     In addition, in the related art, in a case of an oscillator in which the strong excitation is typically carried out after sealing a semiconductor device (IC) and a vibrator element in a package, large power for strong excitation also flows to the semiconductor device, and thus there is a concern that the semiconductor device may be broken. However, in the method of manufacturing the oscillator  1100  according to this embodiment, the strong excitation process (S 20 ) is carried out at a part stage of the vibrator element  100 , and thus it is possible to obtain a stable-quality oscillator  1100  in which the IC  700  to be mounted in the accommodation process (S 40 ) after the strong excitation process (S 20 ) is not affected by the strong excitation at all. In addition, when the strong excitation process (S 20 ) of the third embodiment is carried out under the same conditions as in the strong excitation process (S 5 - 1 ) of the first embodiment, the same effect as in the first embodiment is obtained. 
     In addition, in the method of manufacturing the vibrator  1000  according to the second embodiment, and in the method of manufacturing the oscillator  1100  according to the third embodiment, large power for the strong excitation is applied to the first vibrator element portion  2110  in a type of the vibrator element wafer  2020  (refer to  FIGS. 15A and 15B ). In addition, the defective vibrator element portion  2120 F, which occurs due to the strong excitation, can be detected in a part state as illustrated. 
     That is, as disclosed in the related art (for example, JP-A-2004-297737), in a type in which a vibrator element, or the vibrator element and an IC chip are disposed in a cavity, and the vibrator element is strongly excited, in a case where the vibrator element or the IC chip malfunctions due to the strong excitation, a defective loss is added to the cost of the vibrator element, thereby leading a large loss cost including the part cost of the package, the IC, and the like other than the vibrator element, and the number of processing processes (processing cost). However, according to the above-described manufacturing methods, it is possible to avoid the loss cost. 
     The above-described embodiments are illustrative only, and various modifications can be made without limitation thereto. For example, in the above-described embodiments, as an example of the substrate, the quartz crystal is used as a material having piezoelectric properties, but a silicon semiconductor substrate may be used without limitation thereto. In a case of using the silicon semiconductor substrate as the substrate, electrostatic operation with Coulomb&#39;s force may be used as excitation means. 
     The invention includes a configuration (for example, a configuration in which a function, a method, and a result are the same, or a configuration in which an object and an effect are the same) that is substantially the same as the configuration described in the embodiments. In addition, the invention includes a configuration in which non-essential portions of the configuration described in the embodiments are substituted with other portions. In addition, the invention includes a configuration capable of exhibiting the same operational effect as in the configuration described in the embodiments, and a configuration capable of accomplishing the same object. In addition, the invention includes a configuration in which a technology of the related art is added to the configuration described in the embodiments. 
     The entire disclosure of Japanese Patent Application Nos. 2015-019619, filed Feb. 3, 2015 and 2015-055792, filed Mar. 19, 2015 are expressly incorporated by reference herein.