Abstract:
A method for manufacturing a piezoelectric device comprising steps of preparing a base wafer (S 122 , S 124 ) having a plurality of bases having a first bonding film formed on surrounding of the bases and first dents ( 66 ) formed adjacent to and contacted to the first bonding film; preparing a lid wafer (S 102 , S 104 ) having a plurality of lids having a second bonding film formed on surrounding of the lid and the second dents ( 67 ) formed adjacent to and contacted to the second bonding film; mounting a bonding material ( 75 ) on the first dents ( 66 ) or the second dents ( 67 ); and bonding (S 152 ) the base wafer and the lid wafer by solidifying the bonding material after melting the bonding material and flowing the molten material along the first bonding film and the second bonding film.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to and the benefit of Japan Patent Application No. 2010-076503 filed on Mar. 30, 2010 in the Japan Patent Office, the disclosure of which is incorporated herein by reference in its entirety. 
       FIELD 
       [0002]    The present invention relates to a method for manufacturing a tuning-fork type quartz vibrating piece with a pair of vibrating arms, and a quartz device having the tuning-fork type quartz vibrating piece. 
       DESCRIPTION OF THE RELATED ART 
       [0003]    When the tuning-fork type quartz vibrating piece is miniaturized, a CI value (crystal impedance) or equivalent series resistance becomes large. Then, a technology of forming grooves in front and rear faces of the vibrating arms of the tuning-fork type quartz vibrating piece was proposed, as in U.S. Pat. No. 6,911,765. In the tuning-fork type quartz vibrating piece of U.S. Pat. No. 6,911,765, an increase of the CI value of the tuning-fork type quartz vibrating piece can be held down. On the other hand, there arises a problem that when the grooves including its bottom face and side faces are formed on the front and rear faces of the vibrating arms and excitation electrodes are formed on the bottom face and the side faces, disconnection etc. occurs in the excitation electrodes at positions where the front and rear faces of the vibrating arms bend to the side faces by an angle of 90 degrees. 
         [0004]    In Japan Laid Open 2003-133895, in order to solve this problem, a width of the grooves is made narrower as a base side of the grooves approaches nearer to the base so that the angle may vary gradually from the front and rear faces of the vibrating arms to the side faces, respectively. By adopting such a shape of the grooves, the angles from the front and rear faces of the vibrating arms to the side faces are made gradual. 
         [0005]    Generally, in order to reduce the CI value, it is necessary to make the depth of the grooves in the vibrating arms equal to or deeper than a constant value. Therefore, etching for forming the grooves needs to be performed for a fixed time or longer. However, in the case where the etching was performed so that a shape of the opening in the grooves might be narrower as the location approached nearer to the base side, there was a problem that when the fixed time elapsed, the angles from the front and rear faces of the vibrating arms in the grooves to the side faces became close to 90 degrees. 
       SUMMARY 
       [0006]    It is an object of the present invention to provide a method for manufacturing a tuning-fork type quartz vibrating piece having gradual angles from the front and rear faces of the vibrating arms to the side faces. 
         [0007]    A method for manufacturing a tuning-fork type quartz vibrating piece of a first aspect comprises a photolithography step of applying a resist to an anticorrosion film formed on the quartz material, and exposing a region thereof that corresponds to the base, the vibrating arms, and the grooves by exposing the resist. The method comprises a first etching step of forming an outline of the tuning-fork type quartz vibrating piece by etching the anticorrosion films other than the region that corresponds to the base, the vibrating arms, and the groves and by etching the quartz material; a removal step of removing the anticorrosion film and the resist that remain on the quartz material; and a second etching step of etching at least one of a first fork part formed between the one pair of vibrating arms and the base, and a base-side end face of the grooves by immersing the quartz material in an etchant after the removal step. 
         [0008]    A method for manufacturing a tuning-fork type quartz vibrating piece of a second aspect is that the first etching step and the second etching step use the same temperature and the same etchant, and an etching time of the second etching step is shorter than an etching time of the first etching step. 
         [0009]    A method for manufacturing a tuning-fork type quartz vibrating piece of a third aspect is that he whole front and rear faces of the tuning-fork type quartz vibrating piece exposed by the removal process are immersed in the etchant. 
         [0010]    A method for manufacturing a tuning-fork type quartz vibrating piece of a fourth aspect is that at least one of the first fork part and the end face in the tuning-fork type quartz vibrating piece is covered with a mask and is immersed in the etchant. 
         [0011]    A piezoelectric device having a package having a cavity for storing the tuning-fork type piezoelectric vibration piece manufactured according to anyone of the above first aspect through the fourth aspect. 
         [0012]    A piezoelectric device that is equipped with a lid plate having a first recess part and a base plate having a second recess part and sandwiches the tuning-fork type piezoelectric vibrating piece manufactured by any one of above first aspect through the fourth aspect with the lid plate and the base plate. 
         [0013]    According to the present invention, it is possible to provide a method for manufacturing the tuning-fork type quartz vibrating piece having gradual angles from the front and rear faces of the vibrating arms to the base-side end faces of the fork part or the grooves. Moreover, since light in a photolithography process is exposed onto the fork part or the end faces having gradual angles, there does not occur a problem that an unnecessary metal film remains and thereby an electrical short circuit arises. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a perspective view of the first tuning-fork type crystal vibrating piece  10 A. 
           [0015]      FIG. 2  is a cross-section along the line A-A line of  FIG. 1 . 
           [0016]      FIG. 3  is a cross-section along the line B-B of  FIG. 1 . 
           [0017]      FIG. 4  is an enlarged flat view of a part surrounded by a dotted-line C of  FIG. 1  seen from the +Z side. 
           [0018]      FIG. 6  is a flow chart showing a manufacturing method of the first tuning-fork type crystal vibrating piece  10 A. 
           [0019]      FIG. 7  is a flat view of a half-finished first tuning-fork type crystal vibrating piece  10 A-s. 
           [0020]      FIG. 8A  is a flat view showing a circular crystal wafer  20 - 1  that forms a profile of first tuning-fork type crystal vibrating piece  10 A. 
           [0021]      FIG. 8B  is a flat view showing a rectangular crystal wafer  20 - 2  that forms a profile of first tuning-fork type crystal vibrating piece  10 A. 
           [0022]      FIG. 9  is a flat view of the second tuning-fork type crystal vibrating piece  10 B. 
           [0023]      FIG. 10  is an enlarged view of a part surrounded by the dotted line G of  FIG. 9 . 
           [0024]      FIG. 12  is a flat view showing a half-finished second tuning-fork type crystal vibrating piece  10 B-s in a first variation example. 
           [0025]      FIG. 11  is a flat view of the third tuning-fork type crystal vibrating piece  10 C. 
           [0026]      FIG. 13  is a flat view showing a half-finished third tuning-fork type crystal vibrating piece  10 C-s in a second variation example. 
           [0027]      FIG. 14  is a flat view showing the fourth tuning-fork type crystal vibrating piece  10 D of a third variation example. 
           [0028]      FIG. 15  is a flat view showing the fifth tuning-fork type crystal vibrating piece  10 E of a fourth variation example. 
           [0029]      FIG. 16A  is a side view of the piezoelectric oscillator  100  comprising the first tuning-fork type piezoelectric vibrating piece  10 A. 
           [0030]      FIG. 16B  is a side view of the piezoelectric oscillator  200  comprising the fourth tuning-fork type piezoelectric vibrating piece  10 D. 
           [0031]      FIG. 17A  is an exploded perspective view of the piezoelectric oscillator  300  comprising the fifth tuning-fork type piezoelectric vibrating piece  10 E. 
           [0032]      FIG. 17B  is a cross-sectional view along the line K-K of the piezoelectric oscillator  300  comprising the fifth tuning-fork type piezoelectric vibrating piece  10 E. 
       
    
    
     DETAILED DESCRIPTION 
       [0033]    Each embodiment of the present invention will be explained below by referring figures. 
         [0034]    In the following embodiments, a direction where a vibrating arm extends along a crystal axis of the crystal is a Y-axis direction, a direction of the width of vibrating arm is an X-axis direction, and a direction perpendicular to the X-axis and the Y-axis is a Z-axis. 
       First Embodiment 
       [0035]    &lt;Entire Configuration of the First Tuning-Fork Type Quartz Vibrating Piece  10 A&gt;  FIG. 1  is a perspective view of a first tuning-fork type quartz vibrating piece  10 A. Incidentally, in  FIG. 1 , a +Z side face of the first tuning-fork type quartz vibrating piece  10 A is designated as a “front face Me” and a −Z side face thereof is designated as a “rear face Mi.” Since in the first tuning-fork type quartz vibrating piece  10 A, a shape seen from the front face Me and a shape seen from the rear face Mi are the same, its explanation will be given taking a perspective view of the first tuning-fork type quartz vibrating piece  10 A seen from the front face Me as one example. Similarly, also in a plan view referred to henceforth, its explanation will be given taking only a plan view seen from the front face Me as one example. 
         [0036]    The first tuning-fork type quartz vibrating piece  10 A shown in  FIG. 1  vibrates, for example, at 32.768 kHz, and is extremely miniaturized. For example, the first tuning-fork type quartz vibrating piece  10 A measures about 1.7 mm in whole length in a Y-axis direction, about 0.5 mm in whole width in an X-axis direction, and about 0.4 mm in width in a Z-axis direction. Moreover, the first tuning-fork type quartz vibrating piece  10 A has a base  11  of an almost rectangular shape and a pair of vibrating arms  12 A extending from the base  11  in the +Y-axis direction. Furthermore, widened parts (not illustrated) whose widths in the X-axis direction are designed to be larger than the vibrating arms  12 A may be formed on +Y side distal ends of the one pair of vibrating arms  12 A, respectively. The widened parts enable the one pair of vibrating arms  12 A of the first tuning-fork type quartz vibrating piece  10 A to vibrate easily. 
         [0037]    Since grooves  13 A that are recessed from the front face Me and the rear face Mi of the one pair of vibrating arms  12 A and extend in the Y-axis direction are formed on the front face Me and the rear face Mi thereof, respectively, A-A cross-sectional views of the vibrating arms  12 A are almost H-shaped (see  FIG. 2 ). The grooves  13 A will be explained in detail in following  FIG. 2  to  FIG. 4 . 
         [0038]    Base electrodes  111  of a rectangular shape whose polarities are different from each other (shown by a slashed portion and a netted portion in  FIG. 1 ) are formed on both corners of a −Y side of the base  11 , respectively. Grooves excitation electrodes  131  whose polarities are different from each other are formed in the one pair of the grooves  13 A, respectively. Moreover, side face excitation electrodes  121  of the same polarity are formed on both outsides of the −X side vibrating arm  12 A in the X-axis direction, respectively, and side face excitation electrodes  121  of a polarity different from that of the side face excitation electrodes  121  of the −X side vibrating arm  12 A are formed on both outsides of the +X side vibrating arm  12 A in the X-axis direction, respectively. Metal films  151  to which the side face excitation electrodes  121  on both outsides of the vibrating arms  12 A are to be connected are formed at the +Y-axis side distal ends of the one pair of vibrating arms  12 A, respectively. 
         [0039]    The base electrode  111  is connected to the side face excitation electrode  121  and to the grooves excitation electrode  131  through a connection electrode  141 , respectively. With this configuration, the base electrode  111  conducts electricity to the side face excitation electrode  121  and to the grooves excitation electrode  131 . When the base electrode  111  is connected to an external electrode  118  (see  FIG. 16A ) through an electrically conductive adhesive  116  (see  FIG. 16A ), the external electrode  118  conducts electricity to the side face excitation electrode  121  and to the grooves excitation electrode  131 , respectively, which excites the vibrating arms  12 A of the first tuning-fork type quartz vibrating piece  10 A. 
         [0040]    Each electrode pattern has a configuration where a gold (Au) layer of a thickness of 200 Å to 3000 Å is formed on a chromium (Cr) layer of a thickness of 50 Å to 700 Å. Instead of the chromium (Cr) layer, a tungsten (W) layer, a nickel (nickel) layer, or a titanium (Ti) layer may be used, and a silver (Ag) layer may be used instead of the gold (Au) layer. 
         [0041]    &lt;Configuration of the Grooves  13 A&gt; As shown in  FIG. 1 , each of the one pair of the grooves  13 A has a bottom face M 1 , and a first long side face M 21  (see  FIG. 2 ), a second long side face M 22 , a first short side face M 31 , and a second short side face M 32  that are connected to the bottom face M 1 . Incidentally, the first long side face M 21  (see  FIG. 2 ) extending in the Y-axis direction is provided on a +X side of the bottom face M 1 , and the second long side face M 22  extending in the Y-axis direction is provided on a −X side of the bottom face M 1 . The first short side face M 31  is provided on a −Y side of the bottom face M 1 , and the second short side face M 32  is provided on a +Y side of the bottom face M 1 . 
         [0042]      FIG. 2  is an A-A cross-sectional view of  FIG. 1 . Since the grooves  13 A are formed to be recessed from the front face Me and the rear face Mi of the first tuning-fork type quartz vibrating piece  10 A, as shown in  FIG. 2 , the A-A cross-sectional view of the vibrating arms  12 A becomes almost H-shaped. Moreover, in  FIG. 2 , the grooves  13 A are formed by wet etching so that its width may become narrower toward the center starting from the front face Me and the rear face Mi of the first tuning-fork type quartz vibrating piece  10 A in the Z-axis direction. A depth W 2  of the grooves  13 A is about 35% to 45% of a thickness W 1  of the first tuning-fork type quartz vibrating piece  10 A. 
         [0043]    Here, if an alternating voltage is impressed to the grooves excitation electrode  131  and the side face excitation electrode  121 , an electric field Ex will occur along an arrow direction between the grooves excitation electrode  131  and the side face excitation electrode  121 . Since this electric field Ex works perpendicularly to the electrodes in the vibrating arms  12 A, i.e., linearly, the electric field Ex becomes large. As a result, even in the case where the first tuning-fork type quartz vibrating piece  10 A is miniaturized, a quartz vibrating piece with a small equivalent series resistance can be obtained. 
         [0044]      FIG. 3  is a B-B cross-sectional view of  FIG. 1 . The grooves  13 A formed in the vibrating arms  12 A are formed by the wet etching. The first short side face M 31  on the base  11  side becomes a gentle slope formed to be inclined at a predetermined slope angel β 1  to the front face Me or rear face Mi, and the second short side face M 32  on the distal end side of the vibrating arm  12 A becomes a gentle slope formed to be inclined at a predetermined slope angel β 2  to the front face Me or rear face Mi. Here, it is desirable that the slope angle β 1  is about 120° to 160°. The first short side face M 31  becomes the gentle slope by being wet etched again after the grooves  13 A are formed by the wet etching. 
         [0045]    With such a configuration, when forming the grooves excitation electrode  131  in the grooves  13 A, the photoresist can be applied in uniform thickness on a metal film for electrode in an edge portion E (a first short side S 11 , a second short side S 12 , and a third short side S 13  that will be described later). Moreover, when forming the electrodes by photolithography, the metal film is susceptible to be irradiated by ultraviolet rays. Therefore, the completed electrode pattern has less occurrence of disconnection etc. 
         [0046]      FIG. 4  is an enlarged plan view of a portion surrounded by a dotted line C of  FIG. 1  seen from the +Z side. In order to make the drawing easy to see, each electrode is not drawn in  FIG. 4 . As shown in  FIG. 4 , the first long side face M 21  and the front face Me intersect at a first long side L 11  extending in the Y-axis direction, and the second long side face M 22  and the front face Me intersect at a second long side L 12  extended in the Y-axis direction. The first short side face M 31  and the front face Me intersect at the first short side S 11  connected to the first long side L 11 , intersect at the second short side S 12  connected to the second long side L 12 , and intersect at the third short side S 13  that links the first short side S 11  and the second short side S 12  and extends in the X-axis direction. 
         [0047]    Here, a first angle θ 1  made by the first long side L 11  and the first short side S 11  is smaller than a second angle θ 2  made by the second long side L 12  and the second short side S 12 . 
         [0048]    &lt;Configuration of the First Fork Part  14 A&gt; Below, a first fork part  14 A will be explained in detail referring to  FIG. 4  and  FIG. 5 . As shown in  FIG. 4 , the first fork part  14 A consists of the one pair of the vibrating arms  12 A and the base  11 . 
         [0049]      FIG. 5  is a D-D cross-sectional view of  FIG. 1 . The first fork part  14 A shown in  FIG. 5  has two fork part faces M 41  extending obliquely from the front face Me and the rear face Mi to the center of the Z-axis direction, and a first boundary side Sb formed so that these two fork part faces M 41  may intersect at an almost central position of the first tuning-fork type quartz vibrating piece  10 A in a thickness direction. Here, it is desirable that the slope angle β 3  that the fork part face M 41  makes with the front face Me and the rear face Mi is about 120° to 160°, The fork part face M 41  becomes a gentle slope by being wet etched again after the first fork part  14 A is formed by the wet etching. 
         [0050]    With such a configuration, when forming the connection electrode  141  in the first fork part  14 A, a photoresist can be applied in uniform thickness on the metal film for electrode in the edge portion E (the first fork part side S 14 , the second fork part side S 15 , and the third fork part side S 16  that will be described later) and it is easy to irradiate ultraviolet rays of photolithography. Therefore, the completed electrode pattern has less occurrence of disconnection etc. 
         [0051]    Returning to  FIG. 4 , the first fork part  14 A will be explained continuously. The fork part face M 41  and the front face Me intersect at the first fork part side S 14 , at the second fork part side S 15 , and at the third fork part side S 16 . Here, a first obtuse angle θ 3  made by the first fork part side S 14  and the Y-axis is smaller than a second obtuse angle θ 4  made by the second fork part side S 15  and the Y-axis. 
         [0052]    &lt;Manufacture Method of the First Tuning-Fork Type Quartz Vibrating Piece  10 A&gt; A manufacture method of the first tuning-fork type quartz vibrating piece  10 A will be explained referring to  FIG. 6  to  FIG. 8 .  FIG. 6  is a flowchart showing the manufacture method of the first tuning-fork type quartz vibrating piece  10 A.  FIG. 7  is a plan view showing a semifinished product of the first tuning-fork type quartz vibrating piece  10 A-s.  FIG. 8A  is a plan view showing a circular quartz wafer  20 - 1  that forms an outline of the first tuning-fork type quartz vibrating piece  10 A;  FIG. 8B  is a plan view showing a rectangular quartz wafer  20 - 2  that forms the outline of the first tuning-fork type quartz vibrating piece  10 A. 
         [0053]    In Step S 111  shown in  FIG. 6 , first, a z-cut quartz wafer  20  (see  FIG. 8 , however,  FIG. 8  illustrates a wafer after the first tuning-fork type quartz vibrating piece  10 A was formed) is prepared. Here, the quartz wafer  20  is a wafer of a circular or rectangular shape and is polished to a mirror finished surface. Then, a metal film acting as an anticorrosion film is formed on the whole surface of the entire quartz wafer  20  with a technique of sputtering, vapor deposition, or the like. A metal film such that a gold (Au) layer is deposited on a chromium (Cr) layer is used as the anticorrosion film. 
         [0054]    In Step S 112 , a photoresist layer is uniformly applied to the whole surface of the quartz wafer  20  on which the anticorrosion film was formed, by a technique of spin coat etc. As the photoresist layer, for example, a positive photoresist by a novolac resin is used. 
         [0055]    In Step S 113 , using an exposure apparatus (not illustrated), an outline pattern of the first tuning-fork type quartz vibrating piece  10 A drawn on a photomask is exposed to both surfaces of the quartz wafer  20  to which the photoresist layers were applied. The exposed photoresist is removed by being developed. The gold layer etched from the photoresist layer is etched with respect to the gold layer, for example, using an aqueous solution of iodine and potassium iodide. Subsequently, a chromium layer exposed by the gold layer being removed is etched, for example, using an aqueous solution of diammonium cerium nitrate and acetic acid. These wet etching processes should be done so that excessive portions may not be eroded by adjusting concentrations and temperatures of the aqueous solutions and times of immersion in the aqueous solutions. Then, the exposed quartz wafer  20  is wet etched by being immersed in a wet etchant so that the planar outline (without the grooves) of the first tuning-fork type quartz vibrating piece  10 A may be formed. Here, by the wet etching to the quartz wafer  20 , as shown by solid lines of  FIG. 7 , a semifinished product of the first fork part  14 A-s such that an intersection side of the fork part and the front face Me is one straight line is formed. 
         [0056]    In Step S 114 , the photoresist layer is uniformly applied to the whole surface of the quartz wafer  20  that was wet etched by a technique of spray etc. 
         [0057]    In Step S 115 , using the exposure apparatus (not illustrated), a pattern of a semifinished product of the grooves  13 A-s (see the solid lines of  FIG. 7 ) drawn on the photomask is exposed on the both surfaces of the quartz wafer  20  to which the photoresist layer is applied. The pattern of the semifinished product of the grooves  13 A-s drawn on the photomask is a rectangle seen from the Z-direction. Then, the gold layer exposed from the photoresist layer is wet etched. Subsequently, the chromium layer exposed from the photoresist layer is wet etched. Then, the exposed quartz wafer  20  is wet etched, and the semifinished product of the grooves  13 A-s as shown by the solid lines of  FIG. 7  is formed. Through the above steps, as shown by the solid lines of  FIG. 7 , the semifinished product of the first tuning-fork type quartz vibrating piece  10 A-s that has the semifinished product of the grooves  13 A-s and the semifinished product of the first fork part  14 A-s is formed. 
         [0058]    Next, in Step S 116 , the anticorrosion film and the photoresist that remain on the semifinished product of the first tuning-fork type quartz vibrating piece  10 A-s are removed. Thereby, the whole semifinished product of the first tuning-fork type quartz vibrating piece  10 A-s becomes a state where there exists no anticorrosion film. 
         [0059]    In Step S 117 , the whole semifinished product of the first tuning-fork type quartz vibrating piece  10 A-s is wet etched by being immersed in the wet etchant without a mask. Incidentally, although the etching is done using the same temperature and the same buffered hydrofluoric acid or hydrofluoric acid of Step S 113  or S 115  in Step S 117 , its etching time is shorter than an etching time of Step S 113  or S 115 . Thereby, the whole semifinished product of the first tuning-fork type quartz vibrating piece  10 A-s is etched, and the grooves  13 A and the first fork part  14 A become shapes shown in  FIG. 4 . 
         [0060]    Here, the whole semifinished product of the first tuning-fork type quartz vibrating piece  10 A-s is wet etched by being immersed in the wet etchant without a mask, but the grooves  13 A and the first fork part  14 A (see  FIG. 4 ) shown by dotted lines of  FIG. 7  may be formed using a mask made of rubber so that only a portion shown by a broken line F of  FIG. 7  may be wet etched. 
         [0061]    After undergoing the above process, the quartz wafers  20 - 1 ,  20 - 2  as shown by  FIG. 8A  or  FIG. 8B  are formed. Each of them shows a situation where 13 blocks of the first tuning-fork type quartz vibrating pieces  10 A, each block consisting of four pieces  10 A, are arranged in the circular quartz wafer  20 - 1 . In the circular quartz wafer  20 - 1 , an orientation flat  21 C for specifying a crystal orientation of the quartz is formed in a part of a peripheral part of the quartz wafer  20 - 1  so that its axial direction can be specified. Incidentally, although 39 first tuning-fork type quartz vibrating pieces  10 A are drawn on the quartz wafer  20 - 1  for convenience of explanation, practically, more than hundreds or thousands of the first tuning-fork type quartz vibrating pieces  10 A are formed in the quartz wafer  20 - 1 . The processing is also the same in the rectangular quartz wafer  20 - 2 . 
         [0062]    In Step S 118 , the quartz wafer  20  on which the grooves  13 A and the first fork part  14 A are formed is washed with pure water. Then, in order to form the base electrode  111 , the side face excitation electrode  121 , the grooves excitation electrode  131 , the connection electrode  141 , and the metal film  151  (see  FIG. 1 ), the metal film for electrode of, for example, Au/Cr etc. is formed on the quartz wafer  20  by a technique of vapor deposition, sputtering, or the like. Then, the photoresist is uniformly applied to the metal film for electrode. 
         [0063]    Here, by the wet etching in Step S 117 , the first short side face M 31  (see  FIG. 3 ) and the fork part face M 41  (see  FIG. 5 ) that become the gentle slopes are formed in the grooves  13 A and the first fork part  14 A, respectively. The photoresist can be applied to those edge portions E (see  FIG. 3  and  FIG. 5 ) in uniform thickness. 
         [0064]    Next, the photomask corresponding to the each electrode pattern is prepared and the each electrode pattern is exposed onto the quartz wafer  20  to which the photoresist layer was applied. Here, the each electrode pattern is formed on both faces of the first tuning-fork type quartz vibrating piece  10 A. Since the edge portion E (see  FIG. 3  and  FIG. 5 ) has an obtuse angle, ultraviolet rays are appropriately irradiated on the photoresist. After the photoresist layer is developed, the exposed photoresist layer is removed. The remaining photoresist becomes the photoresist layer corresponding to the electrode pattern. Furthermore, the wet etching of the metal film that becomes an electrode is performed. Thereby, the base electrode  111 , the side face excitation electrode  121 , the grooves excitation electrode  131 , the connection electrode  141 , and the metal film  151  (see  FIG. 1 ) are formed on the front and rear faces of the first tuning-fork type quartz vibrating piece  10 A. Since the edge portion E (see  FIG. 3  and  FIG. 5 ) has an obtuse angle, the electrode pattern without disconnection etc. is formed. 
         [0065]    In Step S 119 , the quartz wafer  20  is cut by the dicing saw to separate the first tuning-fork type quartz vibrating piece  10 A as a unit and the first tuning-fork type quartz vibrating piece  10 A shown in  FIG. 1  is completed. 
       Second Embodiment 
       [0066]      FIG. 9  shows a second tuning-fork type quartz vibrating piece  10 B of a second embodiment. The second tuning-fork type quartz vibrating piece  10 B is the same as that of the first embodiment in other portions except grooves  13 B and a first fork part  14 B. Below, the grooves  13 B and the first fork part  14 B of the second tuning-fork type quartz vibrating piece  10 B will be explained referring to  FIG. 9  and  FIG. 10 . 
         [0067]    &lt;Configuration of the Grooves  13 B&gt;  FIG. 9  is a plan view of the second tuning-fork type quartz vibrating piece  10 B.  FIG. 10  is an enlarged view of a portion surrounded by a dashed line G of  FIG. 9 . In  FIG. 9  and  FIG. 10 , electrodes are not illustrated to improve the clarity of the Figures. 
         [0068]    First, each of the grooves  13 B of vibrating arms  12 B has the bottom face M 1 , and the first long side face M 21 , the second long side face M 22 , a first short side face M 61  and a second short side face M 62  that are connected to the bottom face M 1 . Incidentally, the first long side face M 21  is provided on the +X side of the bottom face M 1 , extending along the Y-axis direction, and the second long side face M 22  is provided on the −X side of the bottom face M 1 , extending along the Y-axis direction. The first short side face M 61  is provided on the −Y side of the bottom face M 1 , and the second short side face M 62  is provided on the +Y side of the bottom face M 1 . 
         [0069]    The first long side face M 21  and the front face Me intersect at the first long side L 11  extending in the Y-axis direction, and the second long side face M 22  and the front face Me intersect at the second long side L 12  extending in the Y-axis direction. The first short side face M 61  and the front face Me intersect at a first short side S 21  connected to the first long side L 11  and at a second short side S 22  connected to the second long side L 12 . 
         [0070]    As shown in  FIG. 10 , a first angle θ 5  made by the first long side L 11  and the first short side S 21  is smaller than a second angle θ 6  made by the second long side L 12  and the second short side S 22 . 
         [0071]    &lt;Configuration of the First Fork Part  14 B&gt; As shown in  FIG. 9 , the first fork part  14 B has two fork part faces M 71  that extend from the front face Me and the rear face Mi to the center in the Z-axis direction, and the first boundary side Sb formed so that the two fork part faces M 71  may intersect almost at the center in the thickness direction of the second tuning-fork type quartz vibrating piece  10 B (see  FIG. 5 ). The fork part face M 71  and the front face Me intersect at a first fork part side S 24  and a second fork part side S 25 . 
         [0072]    As shown in  FIG. 10 , a first obtuse angle θ 7  made by the first fork part side S 24  and the Y-axis is smaller than a second obtuse angle θ 8  made by the second fork part side S 25  and the Y-axis. 
         [0073]    &lt;Manufacture Method of the Second Tuning-fork Type Quartz Vibrating Piece  10 B&gt; In the manufacture method of the second tuning-fork type quartz vibrating piece  10 B, since other steps except Step S 117  of  FIG. 6  are the same as those of the manufacture method of the first tuning-fork type quartz vibrating piece  10 A, only Step S 117  will be explained. 
         [0074]    In Step S 117  shown in  FIG. 6 , the grooves  13 B and the first fork part  14 B shown in  FIG. 9  are formed. Here, the whole second tuning-fork type quartz vibrating piece  10 B may be wet etched by being immersed in the wet etchant without a mask, or the grooves  13   b  and the first fork part  14 B may be formed by only a portion thereof being immersed in the wet etchant with a mask. 
       Third Embodiment 
       [0075]      FIG. 11  shows a third tuning-fork type quartz vibrating piece  10 C of a third embodiment. The third tuning-fork type quartz vibrating piece  10 C is the same as that of the first embodiment in other portions except the grooves  13 C. Below, only the grooves  13 C of the third tuning-fork type quartz vibrating piece  10 C will be explained referring to  FIG. 11 . 
         [0076]    &lt;Configuration of the Grooves  13 C&gt; As shown in  FIG. 11 , the grooves  13 C provided on a pair of vibrating arms  12 C are formed, respectively, in such a manner that a first grooves unit  13 Ca is on a −Y side thereof and a second grooves unit  13 Cb is on a +Y side thereof separatedly. This configuration enables the strength of the one pair of vibrating arms  12 C to be strengthened. 
         [0077]    Explaining it in detail, the first grooves units  13 Ca of the third tuning-fork type quartz vibrating piece  10 C each have a bottom face M 11 , and a first long side face M 23 , a second long side face M 24 , a first short side face M 81 , and a second short side face M 82  that are connected to the bottom face M 11 . 
         [0078]    The first long side face M 23  extending in the Y-axis direction is provided on the +X side of the bottom face M 11 , and the second long side face M 24  extending along the Y-axis direction is provided on the −X side of the bottom face M 11 . The first short side face M 81  is provided on the −Y side of the bottom face M 11 , and the second short side face M 82  is provided on the +Y side of the bottom face M 11 . 
         [0079]    The first long side face M 23  and the front face Me intersect at a first long side L 21  extending in the Y-axis direction, and the second long side face M 24  and the front face Me intersect at a second long side L 22  extending in the Y-axis direction. The first short side face M 81  and the front face Me intersect at the following sides: a first short side S 31  connected to the first long side L 21 , a second short side S 32  connected to the second long side L 22 , and the third short side S 32  that links the first short side S 31  and the second short side S 32  and extends in the X-axis direction. 
         [0080]    Here, a first angle θ 9  made by the first long side L 21  and the first short side S 31  is smaller than a second angle θ 10  made by the second long side L 22  and the second short side S 32 . 
         [0081]    The second short side face M 82  and the front face Me intersect at a fourth short side S 41  connected to the first long side L 21 , at a fifth short side S 42  connected to the second long side L 22 , and at a sixth short side S 43  that links the fourth short side S 41  and the fifth short side S 42  and extends in the X-axis direction. 
         [0082]    Here, a third angle θ 11  made by the first long side L 21  and the fourth short side S 41  is smaller than a fourth angle θ 12  made by the second long side L 22  and the fifth short side S 42 . 
         [0083]    Moreover, as shown in  FIG. 11 , the second grooves units  13 Cb of the third tuning-fork type quartz vibrating pieces  10 C each have a bottom face M 12 , and a first long side face M 25 , a second long side face M 26 , a first short side face M 91 , and a second short side face M 92  that are connected to the bottom face M 12 . 
         [0084]    The first long side face M 25  and the front face Me intersect at the first long side L 31  extending in the Y-axis direction, and the second long side face M 26  and the front face Me intersect at the second long side L 32  extending in the Y-axis direction. The first short side face M 91  and the front face Me intersect at a first short side S 51  connected to the first long side L 31 , at a second short side S 52  connected to the second long side L 32 , and at a third short side S 53  that links the first short side S 51  and the second short side S 52  and extends in the X-axis direction. 
         [0085]    Here, a first angle θ 13  made by the first long side L 31  and the first short side S 51  is smaller than a second angle θ 14  made by the second long side L 32  and the second short side S 52 . For this reason, a perpendicular bisector Gx of the third short side S 53  that links the first short side S 51  and the second short side S 52  and extends in the X-axis direction shifts to the −X side from the center line Bx in the X-axis direction of the vibrating arm  12 C. 
         [0086]    As mentioned above, in the third tuning-fork type quartz vibrating piece  10 C, the first short side face M 81  and the second short side face M 82  of the first grooves unit  13 Ca and the first short side face M 91  of the second grooves unit  13 Cb form gentle slopes whose angles with the front face Me are 120° to 160°. Because of this, when forming the grooves excitation electrodes (not illustrated) in the first grooves unit  13 Ca and the second grooves unit  13 Cb, the photoresist can be applied to the edge portion (see  FIG. 3 ) in uniform thickness on the metal film for electrode and ultraviolet rays are easy to be irradiated onto the photoresist. Therefore, the completed electrode pattern has less occurrence of disconnection etc. 
         [0087]    Although in the third embodiment, the case where the short side face and the front and rear faces intersect at the first short side, at the second short side, and at the third short side was explained, the short side face and the front and rear faces may intersect only at the first short side and at the second short side, as explained in the second embodiment. Moreover, although in the third embodiment, the fork part face has the shape of the first fork part  14 A explained in the first embodiment, it may have the shape of the first fork part  14 B explained in the second embodiment. 
         [0088]    &lt;Manufacture Method of the Third Tuning-Fork Type Quartz Vibrating Piece  10 C&gt; In the manufacture method of the third tuning-fork type quartz vibrating piece  10 C, other steps except Steps S 115  to S 117  of  FIG. 6  are the same as those of the manufacture method of the first tuning-fork type quartz vibrating piece  10 A. 
         [0089]    In Step S 115  shown in  FIG. 6 , using the exposure apparatus (not illustrated), a pattern of the semifinished product (not illustrated) of the first grooves unit  13 Ca and the second grooves unit  13 Cb of rectangular shapes drawn on the photomask is exposed on the both surfaces of the quartz wafer  20  to which the photoresist layers are applied. Next, the gold layer exposed from the photoresist layer is wet etched. Subsequently, the chromium layer that is exposed by the gold layer being removed is wet etched. Then, the exposed quartz wafer  20  is wet etched, forming the semifinished product (not illustrated) of the first grooves unit  13 Ca and the second grooves unit  13 Cb of rectangular shapes. 
         [0090]    In Step S 116 , the anticorrosion film and the photoresist that remain in the semifinished product (not illustrated) of the third tuning-fork type quartz vibrating piece  10 C are removed. In Step S 117 , the whole semifinished product (not illustrated) of the third tuning-fork type quartz vibrating piece  10 C is wet etched by being immersed in the wet etchant. Thereby, the grooves  13 C and the first fork part  14 A shown in  FIG. 11  are formed. Incidentally, the grooves  13 C and the first fork part  14 A shown in  FIG. 11  may be formed using the mask so that only the first short side face M 81  and the second short side face M 82  of the first grooves unit  13 Ca and the first short side face M 91  of the second grooves unit  13 Cb that are shown in  FIG. 11  may be wet etched. 
         [0091]    &lt;First Modification&gt; Regarding the quartz vibrating piece of the first to third embodiments explained so far, as shown by the solid lines of  FIG. 7 , shapes of their the grooves are rectangles. However, the shape of the grooves formed through Steps S 111  to S 115  of  FIG. 6  is not restricted to a rectangle. Below, a first modification will be explained by taking a modification of the second tuning-fork type quartz vibrating piece  10 B of the second embodiment as one example.  FIG. 12  is a plan view showing a semifinished product of the second tuning-fork type quartz vibrating piece  10 B-s in the first modification. 
         [0092]    An intersection shape of a semifinished product of the first fork part  14 B-s and the front face Me that were formed by the process up to Step S 113  explained in  FIG. 6  has a circular arc shape as drawn by a solid line of  FIG. 12 . This is because the photomask at the time of forming an outline pattern of the second tuning-fork type quartz vibrating piece  10 B is formed to be a circular arc. Incidentally, in the process up to Step S 113 , a semifinished product of the grooves  13 B-s shown in  FIG. 12  is not formed, and the second tuning-fork type quartz vibrating piece  10 B is a planar shape. 
         [0093]    By a process of Step S 115 , short-side facing portions of the semifinished product of the grooves  13 B-s are formed to be a circular arc (U-shaped). That is, as drawn by solid lines of  FIG. 12 , an intersection shape of the semifinished product of the grooves  13 B-s and the front face Me has a round rectangular shape with circular arcs on both sides of the Y-axis direction and straight lines on both sides of the X-axis direction. This is because a shape of the groove pattern of the photomask is formed to be a circular arc. 
         [0094]    Then, Step S 117  is performed in the state that is shown by the solid lines of  FIG. 12 , and the grooves  13 B and the first fork part  14 B as shown by dotted lines of  FIG. 12  are formed. 
         [0095]    Although the first modification is a modification of the second embodiment, an idea of the modification is also applied to the first embodiment. That is, in Steps S 113  and S 115  explained in  FIG. 6 , it may be all right that by performing Step S 117  in a state where the semifinished product of the first fork part  14 B-s and the semifinished product of the grooves  13 B-s shown in  FIG. 12  have been formed, the grooves  13 A and the first fork part  14 A (see  FIG. 4 ) that were explained in the first embodiment are formed. Similarly, the idea of the modification is also applied to the third embodiment. 
         [0096]    &lt;Second Modification&gt; Below, a second modification will be explained by taking a modification of a third tuning-fork type quartz vibrating piece  10 C′ of the third embodiment as one example.  FIG. 13  is a plan view showing a semifinished product of the third tuning-fork type quartz vibrating piece  10 C′-s in the second modification. 
         [0097]    A semifinished product of the first fork part  14 C′-s formed by a process up to Step S 113  explained in  FIG. 6  is in the V-shaped that consists of two straight lines as drawn by solid lines of  FIG. 13 . This is because the photomask at the time when an outline pattern of the third tuning-fork type quartz vibrating piece  10 C′ is formed is formed to be V-shaped. Incidentally, in the process up to Step S 113 , a semifinished product of the grooves  13 C′-s shown in  FIG. 13  is not formed, but the third tuning-fork type quartz vibrating piece  10 C′ is a planar shape. 
         [0098]    By a process of Step S 115 , short-side facing portions of the semifinished product of the grooves  13 C′-s are formed to be V-shaped, as shown by the solid lines of  FIG. 13 . This is because the shape of the groove pattern of the photomask is formed to be V-shaped. 
         [0099]    After that, Step S 117  is performed, and the grooves  13 C′ and the first fork part  14 A as shown by dotted lines of  FIG. 13  are formed. Although the second modification is a modification of the third embodiment, an idea of the modification is also applied to the first embodiment and the second embodiment. 
         [0100]    &lt;Third Modification&gt; Below, a fourth tuning-fork type quartz vibrating piece  10 D of a third modification will be explained.  FIG. 14  is a plan view showing the fourth tuning-fork type quartz vibrating piece  10 D of the third modification. Its explanation will be done by attaching the same symbol to the same constituent element as that of the first embodiment. 
         [0101]    &lt;Entire Configuration of the Fourth Tuning-Fork Type Quartz Vibrating Piece  10 D&gt; As shown in  FIG. 14 , the fourth tuning-fork type quartz vibrating piece  10 D has linear symmetry with respect to an axis Ax extending along the Y-axis direction. The fourth tuning-fork type quartz vibrating piece  10 D has a base  21  of an almost rectangular shape and the one pair of vibrating arms  12 A formed extending from the base  21  to the +Y-axis direction. A pair of grooves  13 A is formed on the front faces of the one pair of vibrating arms  12 A. 
         [0102]    Moreover, the fourth tuning-fork type quartz vibrating piece  10 D has a pair of supporting arms  22  formed extending in the +Y-axis direction from the base  21  respectively outside the one pair of vibrating arms  12 A. The one pair of supporting arms  22  has an effect of lessening vibration leakage that vibration of the vibrating arms  12 A leaks to the outside of the fourth tuning-fork type quartz vibrating piece  10 D. Moreover, the one pair of supporting arms  22  has an effect of making a package PK (see  FIG. 16B ) unsusceptible to an influence of temperature variation of the outside or impact therefrom. Here, the one pair of vibrating arms  12 A is configured so that the distance W thereof and the distance W between the vibrating arm  12 A and the supporting arm  22  in the X-axis direction may become the same. 
         [0103]    Moreover, the supporting arm  22  is such that a widened arm part  222  wider than the width of the supporting arm  22  is formed at a +Y side distal end thereof. The widened arm part  222  is a location that is connected with a linkage electrode  216  (see  FIG. 16B ) of the package PK. If the widened arm part  222  has a large area, an area of the connection region to which electrically conductive adhesive  215  ( FIG. 16B ) is applied will become large. Thereby, the connection area becomes larger, so that the fourth tuning-fork type quartz vibrating piece  10 D can be placed in the package PK more securely. 
         [0104]    The fourth tuning-fork type quartz vibrating piece  10 D has second fork parts  24  consisting of the vibrating arms  12 A, supporting arms  22 , and the base  21  respectively outside the one pair of supporting arms  22  in the X-axis direction. Moreover, in the one pair of grooves  13 A, the grooves excitation electrodes  131  of mutually different polarities (shown by oblique lines and by netted lines in  FIG. 14 ) are formed, respectively. On both outsides of the one pair of vibrating arms  12 A in the X-axis direction, the side face excitation electrodes  121  are formed, respectively. 
         [0105]    Extractor electrodes  221  extending along the Y-axis direction are formed on the one pair of supporting arms  22 . The extractor electrode  221  extends as far as the widened arm part  222  in the +Y-axis direction, and extends as far as the base  21  in the −Y-axis direction. Moreover, the extractor electrode  221  is connected to the side face excitation electrode  121  and the grooves excitation electrode  131  through the connection electrode  141 . 
         [0106]    With this configuration, the extractor electrode  221  is made to conduct electricity to the side face excitation electrode  121  and the grooves excitation electrode  131 . When the extractor electrode  221  is connected to external electrodes  217  (see  FIG. 16B ) through the electrically conductive adhesive  215  (see  FIG. 16B ), the external electrodes and the excitation electrodes will conduct electricity, respectively, and the vibrating arms  12 A of the fourth tuning-fork type piezoelectric vibration piece  10 D will vibrate. 
         [0107]    &lt;Configuration of the Second Fork Part  24 &gt; The second fork part  24  shown in  FIG. 14  has two fork part faces M 101  that extend obliquely to the center of the Z-axis direction from the front face Me and the rear face Mi, respectively, and a second boundary side Sb formed so that these two fork part faces M 101  intersect almost at the central position in the thickness direction of the fourth tuning-fork type quartz vibrating piece  10 D. Here, it is desirable that slope angles (see  FIG. 5 ) that the fork part face M 101  makes with the front face Me and the rear face Mi are 120° to 160°. According to such a configuration, the connection electrode  141  can be formed in the second fork part  24  without disconnection. 
         [0108]    The fork part face M 101  and the front face Me intersect at the fourth fork part side S 17 , at the fifth fork part side S 18 , and at the third fork part side S 18 . Here, a third obtuse angle θ 15  made by the fourth fork part side S 17  and the Y-axis is smaller than a fourth obtuse angle θ 16  made by the fifth fork part side S 18  and the Y-axis. For this reason, a perpendicular bisector Jx of the sixth fork part side S 19  that links the fourth fork part side S 17  and the fifth fork part side S 18  and extends in the X-axis direction is shifted to the −X side from the center line Kx between the vibrating arm  12 A and the supporting arm  22  that are adjacent. The second fork part  24  of the third modification may have the same configuration as that of the first fork part  14 B explained in the second embodiment. 
         [0109]    &lt;Manufacture Method of the Fourth Tuning-fork Type Quartz Vibrating Piece  10 D&gt; In the fourth tuning-fork type quartz vibrating piece  10 D of the third modification, the base  21 , the vibrating arms  12 A, and the one pair of supporting arms  22  can be formed in Step S 113  of  FIG. 6  explained in the first embodiment. The second fork part  24  can be formed by the same process as of the first fork part  14 A of the first embodiment. That is, by Step S 113  and Step S 117  of  FIG. 6  that were explained in the first embodiment, the second fork part  24  shown in  FIG. 14  can be formed. 
         [0110]    &lt;Fourth Modification&gt; Below, a fifth tuning-fork type quartz vibrating piece  10 E of a fourth modification will be explained referring to  FIG. 15 .  FIG. 15  is a plan view showing the fifth tuning-fork type quartz vibrating piece  10 E of the fourth modification. Its explanation will be given attaching the same symbol to the same constituent element as that of the third modification. 
         [0111]    As shown in  FIG. 15 , the fifth tuning-fork type piezoelectric vibration piece  10 E is of almost the same configuration as that of the third modification. The fifth tuning-fork type piezoelectric vibration piece  10 E has a pair of supporting arms  32  formed extending in the +Y-axis direction from the excitation base  21  respectively outside the one pair of vibrating arms  12 A in the X-axis direction. Moreover, the fifth tuning-fork type piezoelectric vibration piece  10 E further has an outer frame part  30  of a rectangular shape outside it. This outer frame part  30  is linked to the excitation base  21  through the one pair of supporting arms  32 . 
         [0112]    Extraction electrodes  321  are formed on the front and rear faces of the one pair of supporting arms  32  in the fifth tuning-fork type piezoelectric vibration piece  10 E. The extractor electrodes  321  are formed extending as far as one corner (+X side, +Y side) of the outer frame part  30  and extending as far as the other corner (−X side, −Y side) of the outer frame part  30 , respectively. Moreover, the extractor electrodes  321  are connected to the side face excitation electrode  121  and the grooves excitation electrode  131  through the connection electrode  141 . 
         [0113]    If the extractor electrodes  321  are connected to external electrodes  315  (see  FIG. 17 ) a through electrode  314  (see  FIG. 17 ) with such a configuration, external electrodes  315  and the excitation electrode will conduct electricity, respectively, and the vibrating arms  12 A of the fifth tuning-fork type piezoelectric vibration piece  10 E will vibrate. 
         [0114]    The frame  30  of the fifth tuning-fork type quartz vibrating piece  10 E of the fourth modification can be formed simultaneously with the base  21 , the vibrating arms  12 A, etc. in Step S 113  of  FIG. 6  explained in the first embodiment. 
         [0115]    &lt;First Piezoelectric Device&gt; A piezoelectric vibrator  100  using the first tuning-fork type quartz vibrating piece  10 A explained in the first embodiment will be explained as a first piezoelectric device.  FIG. 16A  is a side view of the piezoelectric vibrator  100  having the first tuning-fork type quartz vibrating piece  10 A. 
         [0116]    As shown in  FIG. 16A , the piezoelectric vibrator  100  is equipped with the package PK having a cavity CT that is constructed with a base plate  112 , a wall  113 , and a lid  114 . The package PK stores the first tuning-fork type quartz vibrating piece  10 A in the cavity CT. The base plate  112  and the wall  113  are formed, for example from a piezoelectric crystal, ceramic, or glass. The lid  114  is made up of a piezoelectric crystal, planar metal of Fe—Ni—Co alloy (kovar), glass, or other materials. The inside of the cavity CT is hermetically sealed with nitrogen gas, vacuum, etc. by a technique of seam welding etc. 
         [0117]    Moreover, a pedestal  115  is provided on a −Y side of the base plate  112  so as to contact the base plate  112  and the wall  113 . The pedestal  115  is also formed with a piezoelectric crystal, ceramic, glass, or the like similarly to the base plate  112  and the wall  113 . The first tuning-fork type quartz vibrating piece  10 A is fixed to the pedestal  115  through the electrically conductive adhesive  116  with its base  11  placed on the pedestal  115 . 
         [0118]    The base electrodes  111  (see  FIG. 1 ) formed in the base  11  are connected to the external electrodes  118  through the electrically conductive adhesive  116  and linkage electrodes  117 , respectively. The linkage electrodes  117  each go through between the base plate  112  and the wall  113  and are connected to the one pair of external electrodes  118  provided on a bottom face of the base plate  112 . If such a configuration is adopted, when an alternating voltage is impressed to the one pair of external electrodes  118 , the vibrating arms  12  of the first tuning-fork type quartz vibrating piece  10 A will be excited. 
         [0119]    Although the piezoelectric vibrator  100  using the first tuning-fork type quartz vibrating piece  10 A was explained, the tuning-fork type quartz vibrating piece explained in the second and third embodiments or the first and second modifications may be used instead of the first tuning-fork type quartz vibrating piece  10 A. 
         [0120]    &lt;Second Piezoelectric Device&gt; A piezoelectric vibrator  200  using the fourth tuning-fork type piezoelectric vibration piece  10 D that was explained in the third modification as the second piezoelectric device will be explained.  FIG. 16B  is a side view of the piezoelectric vibrator  200  having the fourth tuning-fork type piezoelectric vibration piece  10 D. 
         [0121]    As shown in  FIG. 16B , the piezoelectric vibrator  200  is equipped with the package PK having the cavity CT that is constructed with a base plate  211 , a wall  212 , and a lid  213 . The package PK stores the fourth tuning-fork type piezoelectric vibration piece  10 D in the cavity CT. A pedestal  214  is provided almost in the central part of the base plate  211  in the Y-axis direction. The pedestal  214  is also formed with a piezoelectric crystal, ceramic, glass, or the like similarly to the base plate  211  and the wall  212 . The fourth tuning-fork type piezoelectric vibration piece  10 D is fixed on the pedestal  214  through the electrically conductive adhesive  215  with the widened arm part  222  of the supporting arm  22  placed on the pedestal  214 . The extractor electrode  221  (see  FIG. 14 ) formed in the supporting arm  22  is connected to the external electrode  217  through the electrically conductive adhesive  215  and the linkage electrode  216 . 
         [0122]    &lt;Third Device&gt; A piezoelectric vibrator  300  using the fifth tuning-fork type piezoelectric vibration piece  10 E that was explained in the fourth modification as the third piezoelectric device will be explained referring to  FIG. 17 .  FIG. 17A  is an exploded perspective view of the piezoelectric vibrator  300  having the fifth tuning-fork type piezoelectric vibration piece  10 E, and  FIG. 17B  is a K-K cross-sectional view of the piezoelectric vibrator  300  having the fifth tuning-fork type piezoelectric vibration piece  10 E. 
         [0123]    As shown in  FIG. 17A , the piezoelectric vibrator  300  consists of a top lid part  301 , a lowermost base plate  302 , and the fifth tuning-fork type piezoelectric vibration piece  10 E of a central part. Each of the lid part  301 , the base plate  302 , and the fifth tuning-fork type piezoelectric vibration piece  10 E is formed from a piezoelectric material. The lid part  301  has a concave part  311  for lid formed by the wet etching on its one face facing the fifth tuning-fork type piezoelectric vibration piece  10 E. The base plate  302  has a concave part  312  for base formed by the wet etching on its one face facing the fifth tuning-fork type piezoelectric vibration piece  10 E. Therefore, the cavity CT is formed with the concave part  311  for lid and the concave part  312  for base. 
         [0124]    Moreover, base connection electrodes  313  are provided on both sides of the +Z side base plate  302  in the Y-axis direction, respectively. Under the base connection electrodes  313 , the through electrodes  314  are provided, respectively. Furthermore, as shown in  FIG. 17B , one of the through electrodes  314  is connected to an external electrode  315 , and the other of the through electrodes  314  is connected to the external electrode  315 . 
         [0125]    As shown in  FIG. 17B , the piezoelectric vibrator  300  has the fifth tuning-fork type piezoelectric vibration piece  10 E in its center, to whose rear face the base plate  302  is bonded, and to whose front face the lid part  301  is bonded. That is, it has a configuration where the lid part  301  is sealed to the fifth tuning-fork type piezoelectric vibration piece  10 E and the base plate  302  is sealed to the fifth tuning-fork type piezoelectric vibration piece  10 E by a siloxane bond (Si—O—Si) technology. 
         [0126]    With such a configuration, in the fifth tuning-fork type piezoelectric vibration piece  10 E, the extractor electrode  321  conducts electricity to the external electrode  315  through the base connection electrode  313  and the through electrode  314 . It may be all right that the lid part  301 , the fifth tuning-fork type piezoelectric vibration piece  10 E, and the base plate  302  may be bonded, for example, by an anodic bonding technology etc. 
         [0127]    As mentioned above, although the optimal embodiments of the present invention were explained in detail, the present invention can be carried out by adding various changes and modifications within the scope of the technology as is clear for persons skilled in the art. For example, the present invention can be applied to a piezoelectric oscillator having an IC with an oscillation circuit incorporated is placed, other than the piezoelectric vibrator.