Patent Publication Number: US-2013234565-A1

Title: Piezoelectric vibrator, oscillator, electronic device, and radio-controlled timepiece

Description:
RELATED APPLICATIONS 
     This application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2012-053548 filed on Mar. 9, 2012, the entire content of which is hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a piezoelectric vibrator, an oscillator, an electronic device, and a radio-controlled timepiece. 
     2. Description of the Related Art 
     For example, as disclosed in JP-A-2010-119127, it is often the case that a piezoelectric vibrator which makes use of crystal or the like is used as a time source, a timing source for control signals, a reference signal source or the like in a mobile phone or a personal digital assistant. 
     As this kind of piezoelectric vibrator, there has been known a piezoelectric vibrator where a tuning-fork-type piezoelectric vibrating piece is hermetically sealed in a package where a cavity is formed. The package has the structure where a pair of glass substrates in which a recessed portion is formed on one of the glass substrates overlaps each other and is directly bonded to each other thus providing the structure where the recessed portion functions as a cavity. Further, the piezoelectric vibrating piece includes a pair of vibrating arm portions which is arranged parallel to each other, and a base portion to which longitudinal proximal end sides of both vibrating arm portions are integrally fixed. The base portion of the piezoelectric vibrating piece is fixed to a surface of one glass substrate, and both vibrating arm portions of the piezoelectric vibrating piece vibrate in the direction that the vibrating arm portions approach each other or are separated from each other with predetermined resonance frequency using proximal end sides thereof as starting points. 
     Further, through electrodes which penetrate the glass substrate from one surface side to the other surface side of the glass substrate are formed on the glass substrate. The base portion of the piezoelectric vibrating piece and the through electrodes are electrically connected with each other by routing electrodes which extend in the longitudinal direction of the vibrating arm portions on a surface of the glass substrate. As a package of a piezoelectric vibrator, besides the glass package explained above, a ceramic package and the like are known. 
     SUMMARY OF THE INVENTION 
     Conventionally, there has been known the structure where a weight metal film for frequency adjustment is formed on a distal end of a piezoelectric vibrating piece. Usually, a manufacturing process of a piezoelectric vibrator includes a frequency adjustment step where it is confirmed whether or not the frequency of the piezoelectric vibrator falls within a range of nominal frequency for a device, and the frequency is adjusted when the frequency does not fall within the range of nominal frequency for the device. In this frequency adjustment step, the frequency of the piezoelectric vibrator can be increased by evaporating a portion of the above-mentioned weight metal film by the irradiation of a laser beam. 
     However, recently, along with the miniaturization of a piezoelectric vibrator, a distance between a vibrating arm portion and a routing electrode which is arranged parallel to the vibrating arm portion is liable to become narrow. It has been found that, in such a case, splashed weight metal adheres to the routing electrode at the time of laser beam irradiation. When the splashed weight metal adheres to the routing electrode, there arises a possibility that the routing electrode is short-circuited or an electrical characteristic is lowered. Further, when positioning accuracy of a mounting position of the piezoelectric vibrating piece is low, there exists a possibility that the laser beam is directly irradiated to the routing electrode. 
     That is, in the prior art, splashed weight metal adheres to the routing electrode or a laser beam is directly irradiated to the routing electrode and hence, there exists a possibility that an electrical characteristic of the routing electrode is lowered each time the frequency adjustment step is performed. Further, no effective countermeasures have been taken so far for overcoming such a drawback which inventors of the present invention have recently discovered. 
     Accordingly, it is an object of the present invention to provide a piezoelectric vibrator, an oscillator, an electronic device, and a radio-controlled timepiece capable of preventing lowering of an electrical characteristic of a routing electrode during the frequency adjustment with respect to a piezoelectric vibrator whose frequency can be adjusted by irradiating a laser beam onto a weight metal film formed on a distal end of a vibrating arm portion. 
     To achieve the above-mentioned objects, according to one aspect of the present invention, there is provided a piezoelectric vibrator which includes: a package which is formed by bonding a plurality of substrates in a thickness direction; a piezoelectric vibrating piece which is housed in a cavity formed in the package and includes vibrating arm portions which vibrate with predetermined frequency; a weight metal film for frequency adjustment which is formed on a distal end side of the vibrating arm portion; a through electrode which electrically connects an external electrode formed on an outer surface of the package and the inside of the cavity; and a routing electrode which is formed on an inner surface of the cavity and electrically connects the through electrode and the piezoelectric vibrating piece with each other, at least one routing electrode extending substantially parallel to a longitudinal direction of the vibrating arm portion in the vicinity of an inner wall of the cavity, wherein the piezoelectric vibrating piece is mounted in the cavity such that a center line of the piezoelectric vibrating piece is positioned on a side opposite to the routing electrode extending substantially parallel to the longitudinal direction of the vibrating arm portion with respect to a center line of the cavity which extends in the longitudinal direction. 
     In this manner, by mounting the piezoelectric vibrating piece in the cavity such that the center line of the piezoelectric vibrating piece is positioned on a side opposite to the routing electrode extending substantially parallel to a longitudinal direction of the vibrating arm portion with respect to the center line of the cavity which extends in the longitudinal direction of the vibrating arm portion, a distance between the vibrating arm portion and the routing electrode can be widened. Therefore, a possibility of weight metal which splashes at the time of laser beam irradiation adhering to the routing electrode or a laser beam is directly irradiated to the routing electrode can be largely decreased. Accordingly, it is possible to provide a piezoelectric vibrator capable of preventing lowering of an electrical characteristic of the routing electrode at the time of frequency adjustment. It is often the case that at least one routing electrode extends substantially parallel to the longitudinal direction of the vibrating arm portion in the vicinity of the inner wall of the cavity. To explain this point, firstly, by taking into account various conditions at the time of mounting the piezoelectric vibrator on a printed circuit board (a connection position at which the piezoelectric vibrator is connected to a circuit, a space and the like), arranging the external electrodes in the vicinity of an end portion of an outer surface of the package so that a pair of external electrodes which corresponds to different polarities respectively is formed in the vicinity of the end portion of the outer surface of the package at positions spaced farthest apart from each other is unavoidable. In this case, the through electrodes which correspond to the external electrodes respectively are arranged at positions spaced apart from each other in the inside of the cavity. As a result, in order to electrically connect the through electrodes and the piezoelectric vibrating piece with each other, it is necessary to pull around a long distance at least one routing electrode from the through electrode to the piezoelectric vibrating piece. Further, in order to prevent the routing electrode from being exposed to the laser beam irradiation, it is necessary to pull around the routing electrode in a region as distant as possible from the vibrating arm portion. Accordingly, the usual routing electrode is in a situation where forming the routing electrode in the vicinity of the inner wall of the cavity is unavoidable. 
     The above-mentioned piezoelectric vibrator is also characterized in that, the relationship of S&gt;W/2 is established assuming a distance between the center line of the cavity which extends in the longitudinal direction and the center line of the piezoelectric vibrating piece as S and a width of the routing electrode extending substantially parallel to the longitudinal direction of the vibrating arm portion as W. Because of this technical feature, the possibility of adhesion of weight metal to the routing electrode and the possibility of exposure of the routing electrode to laser beam irradiation can be further decreased. That is, it is considered that the greater the width of the routing electrode, the greater the possibility of adhesion of weight metal and the possibility of exposure to laser beam irradiation become. However, according to the extensive studies made by the inventors of the present invention, by setting the positional relationship between the piezoelectric vibrating piece and the routing electrode as set forth above, even when the width of the routing electrode is increased, the position of the piezoelectric vibrating piece is changed correspondingly and hence, the possibility of adhesion of weight metal to the routing electrode and the possibility of exposure of the routing electrode to laser beam irradiation can be further decreased. The numerical value of W/2 is a numerical value based on an experiment carried out by the inventors of the present invention to prove the advantage of the present invention. Further, assuming W as “a width of a region where the routing electrode can be formed”, W may be set such that 2S&gt;W is satisfied. 
     According to another aspect of the present invention, there is provided an oscillator where the above-mentioned piezoelectric vibrator is electrically connected to an integrated circuit as an oscillation element. 
     According to still another aspect of the present invention, there is provided an electronic device where the above-mentioned piezoelectric vibrator is electrically connected to a timer part. 
     According to still another aspect of the present invention, there is provided a radio-controlled timepiece where the above-mentioned piezoelectric vibrator is electrically connected to a filter part. 
     The above-mentioned oscillator, electronic device and radio-controlled timepiece include the piezoelectric vibrator which is excellent in operation reliability and hence, it is possible to provide an oscillator, an electronic device and a radio-controlled timepiece having high performance. 
     As described above, according to the preset invention, it is possible to provide a piezoelectric vibrator, an oscillator, an electronic device, and a radio-controlled timepiece capable of preventing lowering of an electrical characteristic of a routing electrode during the frequency adjustment with respect to a piezoelectric vibrator whose frequency can be adjusted by irradiating a laser beam onto a weight metal film formed on a distal end of a vibrating arm portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing the external appearance of a piezoelectric vibrator; 
         FIG. 2  is a constitutional view showing the inside of the piezoelectric vibrator shown in  FIG. 1 , and is also a plan view of the piezoelectric vibrator in a state where a lid substrate is removed; 
         FIG. 3  is a cross-sectional view of the piezoelectric vibrator taken along a line A-A in  FIG. 2 ; 
         FIG. 4  is an exploded perspective view of the piezoelectric vibrator shown in  FIG. 1 ; 
         FIG. 5  is a flowchart of a manufacturing method of the piezoelectric vibrator; 
         FIG. 6  is an exploded perspective view of a wafer body; 
         FIG. 7  is a constitutional view showing one embodiment of an oscillator; 
         FIG. 8  is a constitutional view showing one embodiment of an electronic device; and 
         FIG. 9  is a constitutional view showing one embodiment of a radio-controlled timepiece. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     (Piezoelectric Vibrator) 
     Hereinafter, a piezoelectric vibrator according to an embodiment of the present invention is explained in conjunction with drawings. 
     In the explanation made hereinafter, the explanation is made assuming a first substrate as a base substrate wafer and a second substrate as a lid substrate wafer. Further, assume a bonding surface of a base substrate where the base substrate is bonded to the lid substrate as an upper surface (inner surface) U, and a surface of the base substrate on a side opposite to the upper surface U as a lower surface L. 
       FIG. 1  is a perspective view showing the external appearance of the piezoelectric vibrator. 
       FIG. 2  is a constitutional view showing the inside of the piezoelectric vibrator, and is also a plan view showing the piezoelectric vibrator in a state where the lid substrate is removed. 
       FIG. 3  is a cross-sectional view of the piezoelectric vibrator taken along a line A-A in  FIG. 2 . 
       FIG. 4  is an exploded perspective view of the piezoelectric vibrator shown in  FIG. 1 . 
     In  FIG. 4 , to facilitate the understanding of the drawings, excitation electrodes  13 ,  14 , routing electrodes  19 ,  20 , mount electrodes  16 ,  17 , and a weight metal film (adjusting film)  21  described later are omitted. 
     As shown in  FIG. 1  to  FIG. 4 , the piezoelectric vibrator  1  of this embodiment is a surface-mounted-type piezoelectric vibrator  1  which includes a package  9  where a base substrate (first substrate)  2  having a rectangular shape as viewed in a plan view and a lid substrate (second substrate)  3  having a rectangular shape as viewed in a plan view are bonded to each other by anodic bonding by way of a bonding film  35 , and a piezoelectric vibrating piece  4  which is housed in a cavity  3   a  of the package  9 . 
     (Piezoelectric Vibrating Piece) 
     The piezoelectric vibrating piece  4  is a tuning-fork-type vibrating piece which is made of a piezoelectric material such as crystal, lithium tantalate, or lithium niobate, and the piezoelectric vibrating piece  4  is vibrated when a predetermined voltage is applied thereto. The piezoelectric vibrating piece  4  includes a pair of vibrating arm portions  10 ,  11  which is arranged parallel to each other, a base portion  12  to which proximal end sides of the pair of vibrating arm portions  10 ,  11  are integrally fixed, and groove portions  18  which are formed on both main surfaces of the pair of vibrating arm portions  10 ,  11  respectively. The groove portion  18  is formed in the vibrating arm portion  10 ,  11  along the longitudinal direction of the vibrating arm portion  10 ,  11  and extends from a proximal end side of the vibrating arm portion  10 ,  11  to an area in the vicinity of an intermediate portion of the vibrating arm portion  10 ,  11 . 
     The excitation electrodes  13 ,  14  and the routing electrodes  19 ,  20  are made of chromium (Cr) which is the same material used for forming background layers of the mount electrodes  16 ,  17  described later. Accordingly, the excitation electrodes  13 ,  14  and the routing electrodes  19 ,  20  can be formed simultaneously at the time of forming the background layers of the mount electrodes  16 ,  17 . 
     The excitation electrodes  13 ,  14  are electrodes which make the pair of vibrating arm portions  10 ,  11  vibrate in the direction that the vibrating arm portions  10 ,  11  approach each other or are separated from each other with predetermined resonance frequency. The first excitation electrode  13  and the second excitation electrode  14  are formed on outer surfaces of the pair of vibrating arm portions  10 ,  11  by patterning in a state where the first excitation electrode  13  and the second excitation electrode  14  are electrically separated from each other. 
     The mount electrodes  16 ,  17  are respectively formed of a laminated film consisting of a Cr film and a gold (Au) film. The mount electrode  16 ,  17  is formed in such a manner that the Cr film which exhibits favorable adhesiveness with crystal is formed as a background layer and, thereafter, the thin Au film is formed on a surface of the Cr film as a finishing layer. 
     A weight metal film  21  is formed on surfaces of distal end portions of the pair of vibrating arm portions  10 ,  11  respectively for making a frequency of the vibrating arm portions  10 ,  11  fall within a range of nominal frequency of a device. The weight metal film  21  is formed of a rough adjustment film  21   a  which is used for roughly adjusting the frequency and a fine adjustment film  21   b  which is used for finely adjusting the frequency. By performing the frequency adjustment using the rough adjustment film  21   a  and the fine adjustment film  21   b , it is possible to make the frequency of the pair of vibrating arm portions  10 ,  11  fall within a range of nominal frequency of the device. 
     (Package) 
     As shown in  FIG. 1  to  FIG. 4 , the base substrate  2  and the lid substrate  3  are substrates made of a glass material such as soda-lime glass, for example, which can be bonded to each other by anodic bonding, and are formed into an approximately plate shape. The cavity  3   a  which houses the piezoelectric vibrating piece  4  therein is formed on a bonding surface side of the lid substrate  3  where the lid substrate  3  is bonded to the base substrate  2 . 
     A bonding film  35  for anodic bonding is formed on the whole of a bonding surface side of the lid substrate  3  where the lid substrate  3  is bonded to the base substrate  2 . That is, the bonding film  35  is formed on a picture frame region around the cavity  3   a  in addition to the whole inner surface of the cavity  3   a . Although the bonding film  35  of this embodiment is made of aluminum (Al), the bonding film  35  may be made of silicon (Si), Cr or the like. As described later, the bonding film  35  and the base substrate  2  are bonded to each other by anodic bonding thus sealing the cavity  3   a  in vacuum. 
     As shown in  FIG. 3 , in the piezoelectric vibrator  1 , the piezoelectric vibrating piece  4  is mounted on an upper surface U of the base substrate  2  where the cavity  3   a  is formed. Accordingly, the piezoelectric vibrator  1  includes a pair of through electrodes  32 ,  33  which penetrates the base substrate  2  in the thickness direction and makes the inside of the cavity  3   a  and the outside of the piezoelectric vibrator  1  conductive with each other. 
     These through electrodes  32 ,  33  are formed in the base substrate  2  having a rectangular shape as viewed in a plan view such that, on the upper surface U, the through electrode  32  is positioned at one end portion of the base substrate  2  in the longitudinal widthwise direction, and the through electrode  33  is positioned at the other end portion of the base substrate  2 . One through electrode  32  is arranged at a position where the through electrode  32  faces the base portion  12  of the piezoelectric vibrating piece  4  in an opposed manner. The other through electrode  33  is arranged in the vicinity of either one of the vibrating arm portions  10 ,  11  of the piezoelectric vibrating piece  4 , for example, a distal end portion  10   a  of the vibrating arm portion  10 , and is arranged at a position offset from the distal end portion  10   a  in the lateral widthwise direction orthogonal to the longitudinal widthwise direction of the base substrate  2 . 
     These through electrodes  32 ,  33  are arranged in through holes  30 ,  31  which penetrate the base substrate  2 , and each through electrode  32 ,  33  is formed of a metal pin  7  which electrically connects the piezoelectric vibrating piece  4  and the outside to each other, and a cylindrical body  6  which is filled in a space defined between the through hole  30 ,  31  and the metal pin  7 . Although the explanation is made hereinafter by taking the through electrode  32  as an example, the same goes for the through electrode  33 . Further, the electrical connection among the through electrode  33 , a routing electrode  37  and an external electrode  39  is set substantially equal to the electrical connection among the through electrode  32 , a routing electrode  36  and the external electrode  39 . 
     As shown in  FIG. 3 , the through hole  30  is formed such that an inner diameter of the through hole  30  is gradually increased from an upper surface U side to a lower surface L side, and a cross-sectional shape of the through hole  30  including a center axis O is formed into a tapered shape. 
     The metal pin  7  is a conductive rod-shaped member made of a metal material such as silver (Ag), a Ni alloy or Al, and is formed by forging or by press-forming. The metal pin  7  is preferably made of metal whose linear expansion coefficient is close to a linear expansion coefficient of a glass material for forming the base substrate  2  such as an alloy (42 alloy) containing 58 weight % of iron (Fe) and 42 weight % of Ni, for example. 
     The cylindrical body  6  is formed by baking glass frit in a paste form. The metal pin  7  is arranged at the center of the cylindrical body  6  so as to penetrate the cylindrical body  6 , and the cylindrical body  6  is firmly and fixedly mounted on the metal pin  7  and the through hole  30 . 
     The pair of routing electrodes  36 ,  37  is formed on an upper surface U side of the base substrate  2  by patterning. One routing electrode  36  is formed at a position where the routing electrode  36  covers the through electrode  32  and faces the base portion  12  of the piezoelectric vibrating piece  4  in an opposed manner. 
     One end portion  37   a  of the other routing electrode  37  is formed on one end portion of the base substrate  2  in the longitudinal widthwise direction at a position where one end portion  37   a  is arranged adjacent to the routing electrode  36  and faces the base portion  12  of the piezoelectric vibrating piece  4  in an opposed manner. The other end portion  37   b  of the routing electrode  37  is formed on the other end portion of the base substrate  2  in the longitudinal widthwise direction at a position where the other end portion  37   b  covers the through electrode  33 . Here, the vibrating arm portions  10 ,  11  of the piezoelectric vibrating piece  4  are provided such that the vibrating arm portions  10 ,  11  are positioned inside one end portion  37   a  of the routing electrode  37  and inside the other end portion  37   b  of the routing electrode  37  in the longitudinal widthwise direction of the base substrate  2 . That is, the vibrating arm portions  10 ,  11  of the piezoelectric vibrating piece  4  are arranged inside the routing electrode  37  along the longitudinal widthwise direction of the base substrate  2 . 
     Further, a strip-shaped portion  37   c  which extends parallel to the vibrating arm portion  10  of the piezoelectric vibrating piece  4  is formed between one end portion  37   a  and the other end portion  37   b  of the routing electrode  37 . The strip-shaped portion  37   c  is, as shown in the drawing, positioned in the vicinity of an inner wall of the cavity  3   a.    
     On one end portion of the base substrate  2  in the longitudinal widthwise direction, a tapered bump (mount portion) B made of Au or the like is formed on the pair of routing electrode  36  and the routing electrode  37  (one end portion  37   a ), and the pair of routing electrodes  36 ,  37  is mounted on the pair of mount electrodes  16 ,  17  which is formed on the base portion  12  of the piezoelectric vibrating piece  4  by making use of the bumps B. Due to such a constitution, one mount electrode  16  of the piezoelectric vibrating piece  4  is made conductive with one through electrode  32  via one routing electrode  36 , and the other mount electrode  17  is made conductive with the other through electrode  33  via the other routing electrode  37 . 
     Due to such a constitution, the piezoelectric vibrating piece  4  is configured such that the base portion  12  is mounted on the bumps B formed on one end portion of the base substrate  2  in the longitudinal widthwise direction, the vibrating arm portions  10 ,  11  extend from the base portion  12  toward the other end portion of the base substrate  2  in the longitudinal widthwise direction, and these vibrating arm portions  10 ,  11  are formed with a gap therebetween in the lateral widthwise direction of the base substrate  2 . 
     A pair of external electrodes  38 ,  39  is formed on the lower surface L of the base substrate  2 . The pair of external electrodes  38 ,  39  is formed on both end portions of the base substrate  2  in the longitudinal widthwise direction respectively, and is electrically connected to the pair of through electrodes  32 ,  33  respectively. 
     In operating the piezoelectric vibrator  1  having such a constitution, a predetermined drive voltage is applied to the external electrodes  38 ,  39  formed on the base substrate  2 . Due to such applying of the drive voltage, it is possible to apply a voltage to the first excitation electrode  13  and the second excitation electrode  14  of the piezoelectric vibrating piece  4  so that the pair of vibrating arm portions  10 ,  11  can be vibrated in the direction that the vibrating arm portions  10 ,  11  approach each other or are separated from each other with predetermined frequency. By making use of the vibrations of the pair of vibrating arm portions  10 ,  11 , the piezoelectric vibrator  1  can be used as a time source, a timing source of a control signal, a reference signal source or the like. 
     In the above-mentioned piezoelectric vibrator  1 , the piezoelectric vibrating piece  4  is arranged such that a center line C 1  of the piezoelectric vibrating piece  4  in the widthwise direction (in the direction that the vibrating arm portions  10 ,  11  are arranged parallel to each other) is offset toward a side opposite to the strip-shaped portion  37   c  of the routing electrode  37  with respect to a center line C 2  of the cavity  3   a  in the lateral widthwise direction. That is, the piezoelectric vibrator  1  is characterized in that the piezoelectric vibrating piece  4  is mounted in the cavity  3   a  such that the center line C 1  of the piezoelectric vibrating piece  4  is positioned on a side opposite to the strip-shaped portion  37   c  of the routing electrode  37  with respect to the center line C 2  of the cavity  3   a  which extends in the longitudinal direction. Due to such a constitution, a distance between the routing electrode  37  and the vibrating arm portions  10 ,  11  can be widened and hence, there exists no possibility that weight metal adheres to the strip-shaped portion  37   c  of the routing electrode  37  particularly or a laser beam is irradiated to the strip-shaped portion  37   c  at the time of performing a frequency adjustment step. Accordingly, there exists no possibility that an electrical characteristic of the routing electrode is lowered. It is preferable that an offset amount S of the center line C 1  of the piezoelectric vibrating piece  4  in the widthwise direction with respect to the center line C 2  of the cavity  3   a  in the lateral widthwise direction is set to satisfies the relationship of S&gt;W/2 with respect to a width W of the strip-shaped portion  37   c  of the routing electrode  37 . That is, the larger the width W of the strip-shaped portion  37   c , the higher the possibility of adhesion of weight metal and the possibility of exposure to laser beam irradiation become. However, by setting the offset amount S corresponding to the width W of the strip-shaped portion  37   c  as described above, it is possible to more surely prevent the adhesion of weight metal and the like. According to extensive studies made by the inventors of the present invention, it is confirmed that, when the offset amount S is set to satisfy the relationship of S=W/3, although the above-mentioned advantageous effect can be acquired to some extent compared to a case where the center line C 1  is not offset at all with respect to the center line C 2 , the advantageous effect is not yet sufficient. On the other hand, it is confirmed that, when the offset amount S is set to satisfy the relationship of S&gt;W/2, the above-mentioned advantageous effect can be acquired sufficiently. Further, by modifying S&gt;W/2 into 2S&gt;W, an upper limit of the width W of the strip-shaped portion  37   c  can be decided. That is, it is difficult to easily change a width size of a package when a mounting environment and business model are taken into consideration. In the same manner, although an offset amount S of the piezoelectric vibrating piece  4  can be also suitably selected, a selectable width range is limited when it is necessary to take into account conditions such as a condition that the piezoelectric vibrating piece  4  should not be brought into contact with the inner wall of the cavity  3   a , and a condition that a bonding state between the mount electrodes  16 ,  17  and the metal bumps B should be maintained. Accordingly, a maximum value of the width W of the strip-shaped portion  37   c  can be set using the above-mentioned formula and hence, different from the prior art, it is unnecessary to decide a position and a size of the strip-shaped portion  37   c  by trial and error by taking into account scattering of weight metal and the like whereby it is possible to more easily provide the piezoelectric vibrator  1  which acquires the above-mentioned advantageous effects. Instead of grasping W as a width of the strip-shaped portion  37   c , W may be grasped as “a region where the strip-shaped portion  37   c  can be formed (a width measured from the inner wall of the cavity  3   a )”. That is, provided that the strip-shaped portion  37   c  is arranged in a region of W which satisfies the above-mentioned formula, the above-mentioned advantageous effects can be acquired irrespective of the width of the strip-shaped portion  37   c.    
     (Method of Manufacturing Piezoelectric Vibrator) 
     Next, a method of manufacturing the above-mentioned piezoelectric vibrator is explained in conjunction with a flowchart. 
       FIG. 5  is a flowchart of a method of manufacturing the piezoelectric vibrator of this embodiment. 
     The method of manufacturing the piezoelectric vibrator according to this embodiment mainly includes a piezoelectric vibrating piece preparation step S 10 , a lid substrate wafer preparation step S 20 , a base substrate wafer preparation step S 30 , and an assembling step (S 50  and steps succeeding S 50 ). Among these steps, the piezoelectric vibrating piece preparation step S 10 , the lid substrate wafer preparation step S 20  and the base substrate wafer preparation step S 30  may be carried out simultaneously. 
     (Piezoelectric Vibrating Piece Preparation Step S 10 ) 
     In the piezoelectric vibrating piece preparation step S 10 , the piezoelectric vibrating piece  4  is prepared. To be more specific, a wafer having a predetermined thickness is formed by slicing a Lambert crystal ore at a predetermined angle and by applying mirror-finish working such as polishing to the sliced Lambert crystal ore. Subsequently, the wafer is patterned using a photolithography technique in accordance with outer shapes of the piezoelectric vibrating pieces  4  and, at the same time, a metal film is formed and patterned thus forming the excitation electrodes  13 ,  14 , the routing electrodes  19 ,  20 , the mount electrodes  16 ,  17  and the weight metal film  21 . 
     Thereafter, the rough adjustment of the resonance frequency of the piezoelectric vibrating piece  4  is performed. To be more specific, a rough adjustment film  21   a  of the weight metal film  21  is evaporated by irradiating a laser beam onto the rough adjustment film  21   a  (see  FIG. 2 ). Due to such treatment, a weight of a distal end side of the pair of vibrating arm portions  10 ,  11  is reduced and hence, the frequency of the piezoelectric vibrating piece  4  is elevated. 
     The piezoelectric vibrating piece preparation step S 10  is finished with the above-mentioned processing. 
     (Lid Substrate Forming Wafer Preparation Step S 20 ) 
     In the lid substrate forming wafer preparation step S 20 , a lid substrate forming wafer  50  which becomes the lid substrate later is prepared. Firstly, a disc-shaped lid substrate forming wafer  50  made of soda lime glass is polished to a predetermined thickness and is cleaned and, thereafter, a working degeneration layer which constitutes an outermost surface is removed by etching or the like (S 21 ). Next, in a cavity forming step S 22 , the plurality of cavities  3   a  are formed on a bonding surface of the lid substrate forming wafer  50  where the lid substrate forming wafer  50  is bonded to a base substrate forming wafer  40 . The cavities  3   a  are formed by thermal press-molding, etching or the like. Next, in a bonding surface polishing step S 23 , the bonding surface of the lid substrate forming wafer  50  where the lid substrate forming wafer  50  is bonded to the base substrate forming wafer  40  is polished. 
     Next, in a bonding film forming step S 24 , the bonding film  35  (see  FIG. 3 ) made of A 1  is formed on the bonding surface of the lid substrate forming wafer  50  where the lid substrate forming wafer  50  is bonded to the base substrate forming wafer  40  described later. The bonding film  35  may be formed on the whole inner surfaces of the cavities  3   a  in addition to the bonding surface of the lid substrate forming wafer  50  where the lid substrate forming wafer  50  is bonded to the base substrate forming wafer  40 . Due to such a step, patterning of the bonding film  35  becomes unnecessary and hence, a manufacturing cost can be reduced. The bonding film  35  may be formed by a film forming method such as sputtering or a CVD. Since the bonding surface polishing step S 23  is performed before the bonding film forming step S 24 , the flatness of the surface of the bonding film  35  is ensured whereby the stable bonding of the lid substrate forming wafer  50  to the base substrate forming wafer  40  can be realized. 
     (Base Substrate Forming Wafer Preparation Step S 30 ) 
     In the base substrate forming wafer preparation step S 30 , the base substrate forming wafer  40  which becomes the base substrate later is prepared. Firstly, a disc-shaped base substrate forming wafer  40  made of soda lime glass is polished to a predetermined thickness and is cleaned and, thereafter, a working degeneration layer which constitutes an outermost surface is removed by etching or the like (S 31 ). 
     (Through Electrode Forming Step S 32 ) 
     Next, a through electrode forming step S 32  where the pairs of through electrodes  32  are formed on the base substrate forming wafer  40  is performed. Although a forming step of the through electrodes  32  is explained hereinafter, the same goes for a forming step of the through electrodes  33 . 
     Firstly, the through holes  30  are formed in the base substrate forming wafer  40  from the lower surface L to the upper surface U by press forming or the like. Next, glass frit is filled in each through hole  30  in a state where the metal pin  7  is inserted into the through hole  30 . The glass frit is mainly constituted of powdery glass particles, an organic solvent, and a binder (a fixing agent). 
     Subsequently, the cylindrical body  6  made of glass, the through hole  30  and the metal pin  7  are integrally formed with each other by baking the glass frit. For example, after conveying the base substrate forming wafer  40  into a baking furnace, the glass frit is baked. Here, an organic solvent, a binder and the like contained in the glass frit are evaporated so that outgases such as carbon monoxide (CO), carbon dioxide (CO 2 ), and water vapor (H 2 O) are generated and are discharged to the outside of the glass frit. 
     Finally, by forming the upper surface U and the lower surface L of the base substrate forming wafer  40  into a flat surface by polishing respectively while exposing the metal pin  7  to the upper surface U and the lower surface L, the through electrode  32  is formed in the inside of the through hole  30 . By forming the through electrode  32 , the electric conductivity between the upper surface U side and the lower surface L side of the base substrate forming wafer  40  is ensured and, at the same time, the through hole  30  formed in the base substrate forming wafer  40  can be sealed. 
     (Routing Electrode Forming Step S 33 ) 
     Next, a routing electrode forming step S 33  where the plurality of routing electrodes  36 ,  37  which are electrically connected to the through electrodes respectively are formed on the upper surface U is performed. Further, the tapered bump made of Au or the like is formed on the routing electrodes  36 ,  37  respectively. In  FIG. 6 , for facilitating the understanding of the drawing, the bumps are not shown in the drawing. The base substrate forming wafer preparation step S 30  is finished at this point of time. 
     (Mounting Step S 50 ) 
     Next, a mounting step S 50  where the piezoelectric vibrating pieces  4  are bonded to the routing electrodes  36 ,  37  formed on the base substrate forming wafer  40  by way of the bumps B respectively is performed. To be more specific, the base portions  12  of the piezoelectric vibrating pieces  4  are placed on the bumps B, and ultrasonic vibrations are applied to the piezoelectric vibrating pieces  4  while heating the bumps B to a predetermined temperature and pushing the piezoelectric vibrating pieces  4  to the bumps B. Due to such an operation, as shown in  FIG. 3 , the base portions  12  are mechanically and fixedly mounted on the bumps B in a state where the vibrating arm portions  10 ,  11  of the piezoelectric vibrating pieces  4  float from the upper surface U of the base substrate forming wafer  40 . 
     (Pre-Heating Step S 60 ) 
     Subsequently, a pre-heating step S 60  where the lid substrate forming wafer  50  and the base substrate forming wafer  40  are pre-heated is performed prior to an anodic bonding step S 70 . The pre-heating step S 60  includes: a setting step S 61  where the lid substrate forming wafer  50  and the base substrate forming wafer  40  are set in the inside of a vacuum chamber; and a respective wafer heating step S 63  where the lid substrate forming wafer  50  and the base substrate forming wafer  40  are respectively pre-heated. 
     In the setting step S 61 , the lid substrate forming wafer  50  and the base substrate forming wafer  40  are set in the inside of a vacuum chamber not shown in the drawing for pre-heating the lid substrate forming wafer  50  and the base substrate forming wafer  40 . 
     In the respective wafer heating step S 63 , the lid substrate forming wafer  50  and the base substrate forming wafer  40  are heated by a heater provided in the inside of the vacuum chamber. 
     In the pre-heating step S 60 , by pre-heating the lid substrate forming wafer  50  and the base substrate forming wafer  40 , an organic solvent, a binder, moisture and the like remaining in the inside of the lid substrate forming wafer  50  and the base substrate forming wafer  40  are evaporated so that outgases such as carbon monoxide (CO), carbon dioxide (CO 2 ) and water vapor (H 2 O) are discharged from the lid substrate forming wafer  50  and the base substrate forming wafer  40 . Accordingly, in performing the anodic bonding step S 70  described later, even when a temperature of the lid substrate forming wafer  50  and a temperature of the base substrate forming wafer  40  are elevated to a bonding temperature, the discharge of outgases can be suppressed. 
     (Anodic Bonding Step S 70 ) 
     Next, the anodic bonding step S 70  where the lid substrate forming wafer  50  and the base substrate forming wafer  40  are bonded to each other by anodic bonding is performed. To be more specific, the anodic bonding is performed in accordance with the following steps. 
     Firstly, the bonding film  35  of the lid substrate forming wafer  50  and the upper surface U of the base substrate forming wafer  40  are brought into contact with each other while maintaining a vacuum state. Then, the lid substrate forming wafer  50  is pressed to the base substrate forming wafer  40  using a pressurizing device not shown in the drawing. Here, a pressing force of the pressurizing device is approximately 500N, for example. 
     Subsequently, the lid substrate forming wafer  50  and the base substrate forming wafer  40  are heated by a heater not shown in the drawing while being pressed by the pressurizing device. The bonding film  35  of the lid substrate forming wafer  50  is connected to an anode electrode of a power source not shown in the drawing, and an electrode plate not shown in the drawing on which the base substrate forming wafer  40  is placed is connected to a cathode electrode of the power source. A voltage of approximately 500V is applied between the respective electrodes, for example. Due to such an operation, the lid substrate forming wafer  50  and the base substrate forming wafer  40  can be bonded to each other by anodic bonding. 
     Next, an external electrode forming step S 80  is performed. In this step, a conductive material is formed on the lower surface L of the base substrate forming wafer  40  by patterning thus forming plural pairs of external electrodes  38 ,  39  (see  FIG. 3 ) where each pair of external electrodes  38 ,  39  is electrically connected to the pair of through electrodes  32 ,  33  respectively. Due to such a step, the piezoelectric vibrating piece  4  is made conductive with the external electrodes  38 ,  39  via the through electrodes  32 ,  33 . 
     Next, a fine adjustment step S 90  is performed. In this step, frequency of the individual piezoelectric vibrator sealed in the cavity  3   a  is finely adjusted in a state of the wafer body  60  such that the frequency falls within a predetermined range. To be more specific, a predetermined voltage is continuously applied to the piezoelectric vibrating piece  4  from the external electrodes  38 ,  39  shown in  FIG. 3  thus measuring frequency while vibrating the piezoelectric vibrating piece  4 . In such a state, a laser beam is irradiated to the piezoelectric vibrating piece  4  from the outside of the base substrate forming wafer  40  thus evaporating the fine adjustment film  21   b  (see  FIG. 2 ) of the weight metal film  21 . Accordingly, a weight of a distal end side of the pair of vibrating arm portions  10 ,  11  is decreased and hence, the frequency of the piezoelectric vibrating piece  4  is increased. By performing the fine adjustment of the frequency of the piezoelectric vibrator  1  as described above, it is possible to make the frequency of the piezoelectric vibrator  1  fall within a range of nominal frequency. 
     After the fine adjustment of frequency is finished, a cutting step S 100  where the bonded wafer body  60  is cut along cutting lines M shown in  FIG. 6  is performed. To be more specific, firstly, a UV tape is adhered to the surface of the base substrate forming wafer  40  of the wafer body  60 . Next, a laser beam is irradiated to the wafer body  60  from a lid substrate forming wafer  50  side along the cutting line M (scribing). Next, the wafer body  60  is broken by pressing a cutting blade to the wafer body  60  from the surface of the UV tape along the cutting line M (breaking). Thereafter, the UV tape is peeled off by irradiating ultraviolet rays (UV). Due to such an operation, the wafer body  60  can be divided into the plurality of piezoelectric vibrators. The wafer body  60  may be cut by other methods such as dicing. 
     It may be possible to change the order of steps such that the fine adjustment step S 90  is performed after dividing the bonded wafer body  60  into individual piezoelectric vibrators by performing the cutting step S 100 . However, by performing the fine adjustment step S 90  prior to the cutting step S 100  as described above, it is possible to perform the fine adjustment of frequency in a form of the wafer body  60  and hence, the fine adjustment of frequency can be performed more efficiently with respect to the plurality of piezoelectric vibrators. Accordingly, the throughput can be enhanced so that this order of steps is preferable. 
     Thereafter, the electrical characteristic inspection S 110  of the inside of the piezoelectric vibrating piece  4  is performed. That is, resonance frequency, a resonance resistance value, drive level characteristics (exciting power dependency of resonance frequency and resonance resistance value) and the like of the piezoelectric vibrating piece  4  are measured and checked. Further, an insulation resistance characteristic and the like of the piezoelectric vibrating piece  4  are also checked. Finally, an appearance inspection of the piezoelectric vibrator is performed so as to make a final check of a size, quality and the like of the piezoelectric vibrator. The manufacture of the piezoelectric vibrator is finished with such processing. 
     As has been explained heretofore, according to this embodiment, it is possible to provide a piezoelectric vibrator, an oscillator, an electronic device, and a radio-controlled timepiece capable of preventing lowering of an electrical characteristic of the routing electrode during the frequency adjustment with respect to the piezoelectric vibrator whose frequency can be adjusted by irradiating a laser beam onto the weight metal film formed on the distal end of the vibrating arm portion. 
     (Oscillator) 
     Next, one embodiment of the oscillator according to the present invention is explained in conjunction with  FIG. 7 . 
     The oscillator  110  of this embodiment is, as shown in  FIG. 7 , formed such that the piezoelectric vibrator  1  is electrically connected to an integrated circuit  111  to function as an oscillation element. The oscillator  110  includes a substrate  113  on which an electronic element part  112  such as a capacitor is mounted. The above-mentioned integrated circuit  111  for oscillator is mounted on the substrate  113 , and the piezoelectric vibrating piece of the piezoelectric vibrator  1  is mounted on the substrate  113  in the vicinity of the integrated circuit  111 . The electronic element part  112 , the integrated circuit  111  and the piezoelectric vibrator  1  are electrically connected with each other by a wiring pattern not shown in the drawing. The respective constitutional parts are molded by a resin not shown in the drawing. 
     In the oscillator  110  having such a constitution, when a voltage is applied to the piezoelectric vibrator  1 , the piezoelectric vibrating piece arranged in the inside of the piezoelectric vibrator  1  vibrates. This vibration is converted into an electric signal due to a piezoelectrical characteristic which the piezoelectric vibrating piece possesses, and is inputted to the integrated circuit  111  as the electric signal. Various processing are applied to the inputted electric signal by the integrated circuit  111 , and the inputted electric signal is outputted as a frequency signal. Accordingly, the piezoelectric vibrator  1  functions as an oscillation element. 
     Further, by selectively setting the constitution of the integrated circuit  111 , for example, an RTC (real time clock) module or the like corresponding to a request, it is possible to impart, besides a function as a timepiece-use single-function oscillator or the like, a function of controlling an operation date and time of the oscillator or an external device or a function of providing time, calendar and the like to the oscillator  110 . 
     According to the oscillator  110  of this embodiment, the oscillator  110  includes the piezoelectric vibrator  1  with high operational reliability and hence, it is possible to provide the oscillator  110  with excellent reliability. 
     (Electronic Device) 
     Next, one embodiment of the electronic device according to the present invention is explained in conjunction with  FIG. 8 . The explanation is made by taking a portable information device  120  which includes the above-mentioned piezoelectric vibrator  1  as an example of the electronic device. Firstly, the portable information device  120  of this embodiment is a device which is represented by a mobile phone, for example, and is a developed or improved form of a conventional wrist watch. The portable information device  120  resembles the wrist watch in appearance. A liquid crystal display is arranged on a portion of the portable information device  120  which corresponds to a dial of the wrist watch, and a present time and the like can be displayed on a screen of the liquid crystal display. Further, when the portable information device  120  is used as a communication device, a user removes the portable information device  120  from his or her wrist, and performs communication in the same manner as a mobile phone of the related art by a speaker and a microphone incorporated into an inner portion of a band. However, the portable information device  120  is remarkably miniaturized and light-weighted compared to the mobile phone of the related art. 
     Next, the constitution of the portable information device  120  of this embodiment is explained. The portable information device  120  includes, as shown in  FIG. 8 , a piezoelectric vibrator  1  and a power source part  121  for power supply. The power source part  121  is formed of a lithium secondary battery, for example. To the power source part  121 , a control part  122  which performs various controls, a timer part  123  which counts time or the like, a communication part  124  which performs communication with the outside, a display part  125  which displays various information, and a voltage detection part  126  which detects voltages of the respective functional parts are connected to each other in parallel. Electricity is supplied to the respective functional parts from the power source part  121 . 
     The control part  122  performs an operational control of the whole system such as the transmission and the reception of voice data and the measurement, display and the like of a present time by controlling the respective functional parts. Further, the control part  122  includes a ROM in which programs are preliminarily written, a CPU which reads and executes the programs written in the ROM, a RAM which is used as a work area of the CPU and the like. 
     The timer part  123  includes an integrated circuit which incorporates an oscillation circuit, a register circuit, a counter circuit, an interface circuit and the like therein, and the piezoelectric vibrator  1 . When a voltage is applied to the piezoelectric vibrator  1 , the piezoelectric vibrating piece vibrates, and the vibrations are converted into an electric signal due to a piezoelectrical characteristic which crystal possesses, and is inputted to the oscillation circuit as the electric signal. An output of the oscillation circuit is binalized and the binalized value is counted by the register circuit and the counter circuit. Then, the transmission/reception of signals is performed between the timer part  123  and the control part  122  via the interface circuit, and a present time, a present date, calendar information and the like are displayed on the display part  125 . 
     The communication part  124  has the substantially same functions as a mobile phone of the related art, and includes a wireless part  127 , a voice processing part  128 , a switching part  129 , an amplifying part  130 , a voice inputting/outputting part  131 , a telephone number inputting part  132 , an incoming call sound generation part  133 , and a calling-control memory part  134 . 
     The wireless part  127  performs the transmission/reception of various data such as voice data with a base station through an antenna  135 . The voice processing part  128  performs coding and decoding of a voice signal inputted from the wireless part  127  or the amplifying part  130 . The amplifying part  130  amplifies a signal inputted from the voice processing part  128  or the voice inputting/outputting part  131  to a predetermined level. The voice inputting/outputting part  131  is formed of a speaker, a microphone or the like, and makes an incoming call sound or a received voice loud or collects voice. 
     Further, the incoming call sound generation part  133  generates an incoming call sound in response to calling from the base station. The switching part  129  switches the amplifying part  130  connected to the voice processing part  128  to the incoming call sound generation part  133  when a call arrives so that the incoming call sound generated by the incoming call sound generation part  133  is outputted to the voice inputting/outputting part  131  through the amplifying part  130 . 
     Here, the calling control memory part  134  stores a program relating to an incoming/outgoing call control in communication. Further, the telephone number inputting part  132  includes, for example, numeral keys ranging from 0 to 9 and other keys. By pushing these numeral keys or the like, a user can input the telephone number of call destination or the like. 
     The voltage detection part  126 , when a voltage applied to the respective functional parts such as the control part  122  from the power source part  121  becomes lower than a predetermined value, detects such lowering of voltage and notifies the lowering of voltage to the control part  122 . The predetermined voltage value at this point of time is a value which is preliminarily set as a minimum voltage necessary for stably operating the communication part  124 , and is set to approximately 3V, for example. The control part  122  which receives the notification of lowering of voltage from the voltage detection part  126  prohibits operations of the wireless part  127 , the voice processing part  128 , the switching part  129  and the incoming call sound generation part  133 . Particularly, the operation stop of the wireless part  127  which consumes large power is inevitable. Further, a message that a remaining battery quantity is short so that the communication part  124  is inoperable is displayed on the display part  125 . 
     That is, due to the combined operation of the voltage detection part  126  and the control part  122 , an operation of the communication part  124  can be prohibited and a message which indicates the prohibition of the operation of the communication part  124  can be displayed on the display part  125 . This display may be formed of a character message. However, as a more intuitive display, a×(bad) mark may be attached to a telephone icon displayed on an upper part of a display screen of the display part  125 . 
     The electronic device is provided with a power source breaking part  136  which can selectively break a power source of a portion relating to a function of the communication part  124 . In this case, it is possible to stop the function of the communication part  124  more reliably. 
     According to the portable information device  120  of this embodiment, the portable information device  120  includes the piezoelectric vibrator  1  with high operational reliability and hence, it is possible to provide the portable information device  120  with excellent reliability. 
     (Radio-Controlled Timepiece) 
     Next, one embodiment of the radio-controlled timepiece according to the present invention is explained in conjunction with  FIG. 9 . 
     The radio-controlled timepiece  140  of this embodiment is, as shown in  FIG. 9 , a timepiece which includes the piezoelectric vibrator  1  which is electrically connected to a filter part  141 , and has a function of receiving a standard electric wave containing timepiece information, automatically correcting time to correct time, and displaying the corrected time. 
     In Japan, transmission installations (transmission stations) which transmit the standard electric wave are located in Fukushima prefecture (40 kHz) and Saga prefecture (60 kHz) and transmit the standard electric waves respectively. A long wave having frequency of 40 kHz or 60 kHz has both of property that the wave propagates on a ground and property that the wave propagates while being reflected between an ionosphere and a ground and hence, the long wave has a wide propagation range whereby the standard electric wave can cover all areas of Japan with the above-mentioned two transmission installations. 
     The functional constitution of the radio-controlled timepiece  140  is explained in detail hereinafter. 
     An antenna  142  receives the standard electric wave formed of a long wave having frequency of 40 kHz or 60 kHz. The standard electric wave formed of a long wave is an electric wave which is obtained by AM-modulating a carrier wave having frequency of 40 kHz or 60 kHz by time information called as a time code. The received standard electric wave formed of a long wave is amplified by an amplifier  143 , and is filtered by a filter part  141  having a plurality of piezoelectric vibrators  1 , and is tuned. The piezoelectric vibrators  1  of this embodiment include crystal vibrator parts  148 ,  149  having resonance frequency of 40 kHz or 60 kHz as same as the above-mentioned frequency of the carrier frequency respectively. 
     Further, a filtered signal of predetermined frequency is detected and demodulated by a detection/rectifying circuit  144 . 
     Subsequently, the time code is taken out through a waveform shaping circuit  145 , and is counted by a CPU  146 . The CPU  146  reads information on a present year, cumulative days, a day of a week, time and the like. The read information is reflected on an RTC  148  so that correct time information is displayed. 
     The carrier wave has frequency of 40 kHz or 60 kHz and hence, crystal vibrator parts  148 ,  149  are preferably formed of a vibrator having the above-mentioned tuning-fork structure. 
     Although the above-mentioned explanation is made with respect to the radio-controlled timepiece used in Japan, the frequencies of standard electric waves of a long wave used overseas differ from the standard electric wave used in Japan. For example, the standard electric wave having frequency of 77.5 kHz is used in Germany. Accordingly, in incorporating the radio-controlled timepiece  140  also compatible with the oversea use into a portable device, the piezoelectric vibrator  1  having frequency different from the frequency used in Japan becomes necessary. 
     According to the radio-controlled timepiece  140  of this embodiment, the radio-controlled timepiece  140  includes the piezoelectric vibrator  1  with high operational reliability and hence, it is possible to provide the radio-controlled timepiece  140  with excellent reliability. 
     Here, the present invention is not limited to the above-mentioned embodiment. 
     In this embodiment, although the constitution which uses a surface-mounted-type glass package where the base substrate  2  and the lid substrate  3  are made of a glass material is exemplified, a ceramic package where the base substrate  2  is made of ceramics and the lid substrate  3  is made of metal, a glass material or the like may be adopted. 
     Further, although the constitution where the bump B made of gold (Au) or the like is formed on the routing electrodes  36 ,  37  and the piezoelectric vibrating piece  4  is mounted on the routing electrodes  36 ,  37  by making use of the bumps B is exemplified, the constitution where the piezoelectric vibrating piece  4  is mounted on the routing electrodes  36 ,  37  using a conductive adhesive agent in place of the bump B made of gold (Au) or the like may be adopted. 
     Besides the above-mentioned modifications, it is possible to make a choice among the above-mentioned constitutions and to suitably change the above-mentioned constitution to other constitution without departing from the gist of the present invention.