JP2007028580A - Piezoelectric oscillating piece, piezoelectric oscillator, and frequency adjustment method for piezoelectric oscillating piece - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a more highly reliable piezoelectric oscillating piece, a piezoelectric oscillator comprising the same, and a frequency adjustment method for the piezoelectric oscillating piece by which insulation is surely secured between exciting electrode of different poles and frequency adjustment efficiency of the piezoelectric oscillating piece is not reduced even if a part of a metal material is scattered in frequency adjustment without disturbing the oscillation of the piezoelectric oscillating piece. <P>SOLUTION: A piezoelectric oscillating piece comprises: adjustment electrodes 25, 26 in each of which a frequency is adjusted by increasing and decreasing a mass of an electrode comprised of a metal material; and exciting electrodes 231, 241 configured of the adjustment electrodes via non-electrode regions 212, 222 in different poles from the adjustment electrodes. Insulating films 3 are formed over upper portions of the non-electrode regions and the exciting electrodes and the insulating film in the vicinity of the non-electrode region including boundaries of the non-electrode regions, and the exciting electrodes is formed thicker than that of the other region. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a piezoelectric vibrating piece including a base and a plurality of legs protruding from the base, a piezoelectric vibrator including the piezoelectric vibrating piece, and a frequency adjusting method for the piezoelectric vibrating piece. In particular, the present invention relates to an improvement for avoiding defects such as a short circuit between electrodes formed on the surface of a piezoelectric vibrating piece by frequency adjustment.

  A conventional piezoelectric vibrating piece will be described by taking a tuning-fork type quartz vibrating piece as an example. For example, the quartz vibrating piece includes a base and two legs protruding from the base. Excitation electrodes are formed on the outer surfaces of the base portion and the leg portions, and an adjustment electrode for frequency adjustment is formed at the distal end portion of each leg main surface. For example, the first excitation electrode is formed on the front and back main surfaces of one leg and both side surfaces of the other leg, and the excitation electrode is formed on both side surfaces of one leg and the front and back main surfaces of the other leg. Two excitation electrodes are formed. That is, a first excitation electrode is formed at the center of one leg front and back main surfaces, and a second excitation electrode is formed on a side surface that is spaced apart from the first excitation electrode and close to the ridge of the leg, A second excitation electrode is formed at the center of the front and back main surfaces of the other leg, and a first excitation electrode is formed on a side surface that is spaced apart from the second excitation electrode and close to the ridge of the leg.

By the way, since each of the leg portions is configured with adjacent excitation electrodes (first excitation electrode and second excitation electrode) in close proximity, foreign matter such as dust is present between these electrodes (non-electrode region). If attached, the electrode may be short-circuited, causing oscillation to stop. Therefore, some conventional tuning-fork type crystal vibrating pieces have a structure in which the surface of the excitation electrode is covered with an insulating film as shown in Patent Document 1 to improve the short circuit of the electrode.
JP 2001-144582 A

  However, the piezoelectric vibrating piece described above has the following problems.

  When forming an insulating film on the main surface of the piezoelectric vibrating piece or on all excitation electrodes on the main surface, it is necessary to set the thickness as thin as possible so as not to hinder the vibration of the piezoelectric vibrating piece. is there. In particular, if the insulating film is formed with a thickness larger than 0.03 μm for most of the excitation electrodes, the vibration of the piezoelectric vibrating piece is inhibited, the CI value characteristic is extremely lowered, and the thickness of the insulating film is further increased. In some cases, non-oscillation was caused.

  If the insulating film is formed with a thin thickness so as not to hinder the vibration of the piezoelectric vibrating piece, a slight electrode exposure area where the insulating film is not completely applied may be formed at the edge of the upper end of the excitation electrode. there were. If this electrode exposure area is in the vicinity of the adjustment electrode, the metal material scattered by the adjustment is removed by this adjustment when the frequency adjustment electrode is removed by dry etching techniques such as laser beam and milling. By reaching the exposed region, the electrode may be short-circuited, causing oscillation to stop.

  Moreover, if all the excitation electrodes on the main surface or all the excitation electrodes on the main surface are covered with an insulating film, even if an adjustment electrode made of a metal material is formed on the upper surface, the adhesion strength decreases. In particular, when the thickness of the adjustment electrode is increased, the adjustment electrode may be peeled off. For this reason, the same insulating film as that of the insulating film is laminated on the upper portion, and adjustment for reducing the frequency is performed. However, compared with the case where the adjustment electrode made of a metal material is formed, there is a problem that a material having a high specific gravity cannot be selected, the frequency adjustment time is increased, and the frequency adjustment efficiency is extremely deteriorated. In addition, if all the excitation electrodes on the main surface or all the excitation electrodes on the main surface are covered with an insulating film, the adjustment electrode is removed by a method such as milling, and adjustment is performed to increase the frequency compared to metal materials. In addition, the removal rate is low, the frequency adjustment time is increased, and the frequency adjustment efficiency is extremely deteriorated.

  In addition, when performing adjustment to remove the adjustment electrode by dry etching technique such as milling and increase the frequency, there is a problem that the dry etching region shifts due to the mutual positional relationship between the piezoelectric vibrating piece and the mask member. In the ultra-small piezoelectric vibrating piece that has been developed in recent years, these problems are conspicuous. In particular, the piezoelectric vibrating piece, a holder for holding the piezoelectric vibrating piece, and a mask member in which only the adjustment electrode portion of the piezoelectric vibrating piece is opened are combined to position each other. However, as the piezoelectric vibrating piece is reduced in size, the influence of tolerance on each component increases, and mask displacement occurs due to slight displacement. For this reason, the dry etching region is shifted from the adjustment electrode, so that the desired frequency adjustment cannot be obtained, and the frequency adjustment efficiency is extremely deteriorated.

  The above problems are prominent in an ultra-small piezoelectric vibrator that has been developed in recent years.

  The present invention has been made in view of the above points, and the object of the present invention is to prevent the vibration of the piezoelectric vibrator from being disturbed, even if a part of the metal material is scattered by frequency adjustment. Highly reliable piezoelectric vibrating piece, piezoelectric vibrator including the piezoelectric vibrating piece, and frequency adjustment of the piezoelectric vibrating piece that can reliably ensure the insulation of the excitation electrode and do not reduce the frequency adjustment efficiency of the piezoelectric vibrating piece It is to provide a method.

  In order to achieve the above object, a piezoelectric vibrating piece according to claim 1 of the present invention includes an adjustment electrode having a frequency adjusted by increasing / decreasing the mass of an electrode made of a metal material, and a non-adjustment from the adjustment electrode. An adjustment electrode and an excitation electrode configured to have a different polarity are provided via an electrode region, an insulating film is formed on the electrodeless region and the excitation electrode, and the electrodeless region and the excitation electrode The insulating film in the vicinity of the electrodeless region including the boundary portion was formed thicker than the other regions.

  With the above configuration, an insulating film is formed on the electrodeless region and the excitation electrode, and an insulating film near the electrodeless region including the boundary between the electrodeless region and the excitation electrode is formed thicker than other regions. Therefore, the insulating film is completely applied also to the ridge portion of the upper end portion of the excitation electrode adjacent to the adjustment electrode, so that no electrode exposure area is formed. That is, even if a foreign substance adheres between the adjustment electrode and the excitation electrode or a metal material or the like that travels from the adjustment electrode to the excitation electrode due to frequency adjustment is scattered, there is no short circuit and no oscillation is stopped.

  In addition, an insulating film is formed on the electrodeless region and on the excitation electrode, and no insulating film is formed on the adjustment electrode made of a metal material, and the adjustment electrode is exposed on the surface. It becomes easy to form the adjustment electrode made of the material, and the material having high adhesion and specific gravity can be selected. In addition, since the adjustment electrode made of a metal material is exposed on the surface, the removal rate of the adjustment electrode does not decrease even if the frequency is adjusted by a dry etching technique such as milling. As described above, the frequency adjustment time is shortened, and the frequency adjustment efficiency is dramatically increased.

  The piezoelectric vibrating piece according to claim 2 of the present invention is a piezoelectric vibrating piece including a base portion and a plurality of leg portions protruding from the base portion, and each leg portion is formed at a tip portion of a leg main surface. An adjustment electrode whose frequency is adjusted by increasing / decreasing the mass of the electrode made of a metal material, and the adjustment electrode formed in the center of the leg main surface from the adjustment electrode via a first electrodeless region, A main surface central excitation electrode configured differently from the main surface, and an end excitation electrode formed close to the ridge of the leg portion from the main surface central excitation electrode via the second electrodeless region And an insulating film is formed on the first electrodeless region, the main surface central excitation electrode, and the second electrodeless region, and a boundary between the first electrodeless region and the main surface central excitation electrode. The insulating film in the vicinity of the first electrodeless region including the portion was formed thicker than the other regions.

  With the above configuration, an insulating film is formed on the first electrodeless region, the main surface central excitation electrode, and the second electrodeless region, and the first electrodeless region and the main surface central excitation electrode are formed. Since the insulating film in the vicinity of the first electrodeless region including the boundary portion is formed thicker than the other regions, the insulating film is also insulated from the ridge portion at the upper end portion of the main surface central excitation electrode adjacent to the adjustment electrode. The film is completely applied, and no electrode exposed area is formed. That is, even if a foreign substance adheres between the adjustment electrode and the main surface central excitation electrode or a metal material or the like directed from the adjustment electrode to the excitation electrode scatters due to frequency adjustment, there is no short circuit and no oscillation is stopped.

  In addition, since the insulating film is formed on the first electrodeless region and the upper surface of the main surface central excitation electrode, the insulating film is not formed on the upper portion of the adjustment electrode made of a metal material, and the adjustment electrode is exposed on the surface. Thus, it becomes easy to form an adjustment electrode made of a metal material on the upper surface, and a material having high adhesion and specific gravity can be selected. In addition, since the adjustment electrode made of a metal material is exposed on the surface, the removal rate of the adjustment electrode does not decrease even if the frequency is adjusted by a dry etching technique such as milling. As described above, the frequency adjustment time is shortened, and the frequency adjustment efficiency is dramatically increased.

  According to a third aspect of the present invention, in each of the above structures, the thickness of the insulating film not formed on the thick film is set to 0.005 μm to 0.03 μm.

  In this case, in addition to the above-described operational effects, insulation can be reliably ensured even if foreign matter such as dust adheres to each excitation electrode without hindering the vibration of the piezoelectric vibrating piece. When the thickness of the insulating film not formed on the thick film is less than 0.005 μm, the insulating property cannot be ensured due to adhesion of foreign matters such as dust, and a problem such as a short circuit may occur between electrodes of different polarities. When the thickness of the insulating film not formed on the thick film is greater than 0.03 μm, the vibration of the piezoelectric vibrating piece is inhibited and the CI value characteristic is extremely lowered.

  According to a fourth aspect of the present invention, in the above configuration, the main surface of the leg portion has a groove portion, and a part of the main surface central excitation electrode is formed inside the groove portion.

  In this case, in addition to the above-described effects, the main surface of the leg portion has a groove portion, and a part of the main surface central excitation electrode is formed inside the groove portion. The vibration loss of the leg is suppressed, and the CI value (crystal impedance) can be kept low.

  According to a fifth aspect of the present invention, in the above configuration, the piezoelectric vibrating piece is made of quartz and the insulating film is made of silicon oxide.

  In this case, in addition to the above-described effects, the thermal expansion coefficient is approximated, and a more preferable insulating film that hardly inhibits the vibration of the piezoelectric vibrating piece is obtained.

  Further, in order to achieve the above object, the piezoelectric vibrator according to the present invention is characterized in that the above-described piezoelectric vibrating piece according to the present invention is mounted.

  According to the present invention, it is possible to provide a piezoelectric vibrator that has the same effects as the piezoelectric vibrating piece according to the present invention.

  Further, in order to achieve the above object, the frequency adjusting method of the piezoelectric vibrating piece according to the present invention as described above, wherein only the insulating film portion of the thick film adjacent to the adjusting electrode and the adjusting electrode is provided. Are simultaneously dry-etched.

  According to the present invention, since only the adjustment electrode and the thick insulating film portion adjacent to the adjustment electrode are simultaneously dry-etched, the adjustment electrode is dry with a much higher removal rate than the insulating film. The excited electrode under the insulating film is never removed unnecessarily. In addition, by dry etching only the insulating film portion of the thick film, it is difficult to generate the electrode exposure area, and even if a metal material or the like from the adjustment electrode toward the excitation electrode is scattered, it may cause a short circuit and stop oscillation. Absent. In addition, since it can be expanded to the insulating film portion as well as the adjustment electrode and dry etching can be performed, when using a mask member, the tolerance of the holder holding the piezoelectric vibrating piece and the mask member can be given a margin, The adverse effect of mask displacement can be reduced. Since the tolerance of the holder and the mask member can be given a margin, the opening of the mask member can be enlarged, and as a result, the frequency adjustment efficiency can be lowered by shifting the dry etching region from the adjustment electrode. Disappear. Furthermore, when dry etching is performed in a single state or a wafer state before the piezoelectric vibrating piece is mounted on the package, the frequency can be adjusted without a mask member according to the output state of the dry etching.

  According to the present invention, even if a part of the metal material is scattered by adjusting the frequency without hindering the vibration of the piezoelectric vibrator, the insulation of the excitation electrode with a different polarity can be reliably ensured, and the piezoelectric vibrating piece A highly reliable piezoelectric vibrating piece, a piezoelectric vibrator including the piezoelectric vibrating piece, and a method of adjusting the frequency of the piezoelectric vibrating piece can be provided without reducing the frequency adjustment efficiency.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiment, a case where the present invention is applied to a tuning fork type crystal vibrating piece as a piezoelectric vibrating piece is shown. FIG. 1 is a plan view showing a quartz wafer 1 according to this embodiment, and FIG. 2 schematically shows a tuning-fork type quartz vibrating piece 2 according to this embodiment, showing the arrangement of excitation electrodes 23 and 24. FIG. 3 is a cross-sectional view taken along line AA in FIG. 2, and FIG. 4 is a cross-sectional view taken along line BB in FIG. FIG. 5 is a sectional view taken along the line CC of FIG.

  As shown in FIG. 1, a tuning fork type crystal vibrating piece 2 is obtained by a method such as photolithography from a single wafer 1, and an excitation electrode or the like is formed before separating each crystal vibrating piece. Is done.

  The tuning fork type crystal vibrating piece 2 includes a base portion 20 and two leg portions 21 and 22 protruding from the base portion, and groove portions 211 and 221 are formed on the main surfaces (front and back surfaces) of the leg portions. Yes. The groove part here may be a through hole or a hollow part. First and second excitation electrodes 23 and 24 are formed on the outer surfaces of the base and the leg, and the frequency is adjusted by increasing or decreasing the mass of the electrode at the tip of each leg main surface. Adjustment electrodes 25 and 26 are formed. The first excitation electrodes 23 are formed on the front and back main surfaces of the leg portion 21 and the ridges of the leg portions 22, and the excitation electrodes 23 and 24 are formed on the leg portions 22. Second excitation electrodes 24 are formed on the front and back main surfaces.

  That is, the leg 21 has the adjustment electrode 25 formed at the tip, and the main surface central excitation 231 is formed from the adjustment electrode 25 to the center of the front and back main surfaces via the first electrodeless portion 212. An end excitation electrode 242 is formed from the surface center excitation electrode 231 through the second non-electrode portion 213 in the vicinity of the ridge of the leg portion. An adjustment electrode 26 is formed at the tip of the leg portion 22, and a main surface central excitation 241 is formed from the adjustment electrode 26 to the center of the front and back main surfaces via the first electrodeless portion 222. An end excitation electrode 232 is formed from the excitation electrode 241 through the second non-electrode portion 223 to be close to the ridge of the leg portion.

  In these excitation electrodes 23 and 24, a thin film of gold (Au) or the like is formed on a chromium (Cr) layer formed by metal deposition by a method such as photolithography. As with the excitation electrode, the adjustment electrodes 25 and 26 are formed by forming a thin film such as gold (Au) on the upper layer of chromium (Cr) by a method such as photolithography, forming an insulating film 3 to be described later, and then forming an upper portion thereof. Further, silver (Ag) or the like is a thin film formed by metal deposition using a deposition mask or sputtering. For example, similar silver (Ag) is added to the adjustment electrodes 25 and 26, or a part of the adjustment electrodes 25 and 26 is removed by beam irradiation or milling, so that the oscillation frequency of the tuning-fork type crystal vibrating piece 2 is obtained. Can be adjusted. At this time, the adjustment electrodes 25 and 26 are formed so that the oscillation frequency of the vibrator before the frequency adjustment is higher than the target frequency when frequency adjustment is performed centering on electrode addition, and the frequency adjustment is performed centering on electrode removal. The oscillation frequency of the vibrator 1 before frequency adjustment is formed to be lower than the target frequency. In the embodiment of the present invention, in order to carry out frequency adjustment with higher accuracy, a similar silver (Ag) is added to the adjustment electrodes 25 and 26 by metal vapor deposition or a part of the adjustment electrodes 25 by laser beam irradiation. The frequency coarse adjustment is performed by removing the frequency, and then the frequency is finely adjusted by generally removing the same adjustment electrodes 25 and 26 by a dry etching technique such as milling.

In the tuning-fork type crystal vibrating piece 2, the first electrodeless portions 212 and 222, the main surface central excitation electrodes 231 and 241, and the second electrodeless portion 213, excluding the adjustment electrodes 25 and 26. , 223, an insulating film 3 made of SiO ₂ (silicon oxide) is formed at least on the front and back main surface portions of the tuning-fork type quartz vibrating piece by a method such as vapor deposition or sputtering. At this time, the insulating film 3 may be formed on both side portions in addition to the front and back main surface portions of the tuning-fork type crystal vibrating piece. The thickness of the insulating film 3 deposited here is preferably about 0.005 to 0.03 μm. As a result, even if foreign matter such as dust adheres between the main surface central excitation electrodes 231 and 241 and the end excitation electrodes 232 and 242, which are different polarity excitation electrodes, insulation can be reliably ensured, and the tuning fork The CI value characteristic is not deteriorated by inhibiting the vibration of the quartz crystal vibrating piece.

  In this embodiment, only a part of the insulating film 3 including the ridges at the upper ends of the main surface central excitation electrodes 231 and 241 and the first electrodeless portions 212 and 222 are about 0.05 to 0. .2 μm thick film (thickness increasing portion 31). As a result, the insulating film is completely applied to the ridges at the upper end portions of the main surface central excitation electrodes 231 and 241 adjacent to the adjustment electrodes 25 and 26, so that no exposed electrode region is formed. As a result, even if the metal material is scattered from the adjustment electrodes 25 and 26 toward the main surface central excitation electrodes 231 and 241 by removing the frequency adjustment electrode by a method such as laser beam or milling, the frequency adjustment is performed. And no oscillation stops.

  The thickness-increasing portion 31 of the insulating film is only a part including the ridge portion of the upper end portion of the main surface central excitation electrodes 231 and 241 and the first electrodeless portions 212 and 222, but FIG. As shown in FIG. 5, the electrode may be formed only in the vicinity of the boundary between the one electrodeless region 212, 222 and the main surface central excitation electrode 231, 241. As shown in FIG. 6B, if the thickness of the increased thickness portion 31 of the insulating film is larger than the main surface central excitation electrodes 231 and 241, it is formed only on the first electrodeless portions 212 and 222. May be. Further, as shown in FIG. 6C, a part including the ridges at the upper ends of the main surface central excitation electrodes 231 and 241 and a part of the first electrodeless parts 212 and 222 and the adjustment electrodes 25 and 26. It may be formed to protrude.

  As described above, in order to make part of the thickness of the insulating film 3 different, after the uniform portion is formed, it is very easily formed by a plurality of vapor deposition steps using a mask that exposes only the thickened portion 31. be able to. As shown in FIG. 7, if a mask 4 in which only the first electrodeless portion is opened larger than other regions is used, only a part of the thickness of the insulating film is varied by a single vapor deposition process. It can also be formed.

  The insulating film 3 is one of the first and second excitation electrodes 23 and 24 and the adjustment electrodes 25 and 26 made of gold (Au) or the like on an upper layer of chromium (Cr) formed by a method such as photolithography. The part is formed after the legs 12 and 13 are formed. Then, after the insulating film 3 including the thickened portion is formed, a part of the adjustment electrodes 25 and 26 made of silver (Ag) or the like formed using a mask is formed only on the upper surface. For this reason, even if part of the electrode material is scattered in advance when forming the electrode for a part of the adjusting electrode (such as silver) formed by a technique such as metal vapor deposition or sputtering using a mask. By forming the insulating film 3, there is no short circuit between the adjustment electrode, the main surface center excitation electrode, and the end excitation electrode, thereby causing no oscillation stop.

  The tuning fork type crystal vibrating piece 1 is mounted inside a package (not shown) in which, for example, a package base (not shown) and a cap (not shown) are joined to form an airtight space therein. Thus, a tuning fork type crystal resonator (not shown) is configured.

  Note that the insulating film 3 is not formed on the adjustment electrodes 25 and 26, and it becomes easy to form an adjustment electrode made of a metal material on the upper surface, and a material having a high specific gravity can be selected. Further, since the adjustment electrodes 25 and 26 made of a metal material are exposed on the surface, even if the frequency is adjusted by a technique such as milling, the removal rate of the adjustment electrode does not decrease. For this reason, the frequency adjustment time is shortened, and the frequency adjustment efficiency is dramatically increased.

Further, in the embodiment of the present invention, when performing fine adjustment to increase the frequency by removing the adjustment electrodes 25 and 26 by a dry etching technique such as milling, it corresponds to the removal rate time optimum for the silver material that is the adjustment electrode. The output setting for dry etching is set. For example, with a silver material, the output of the milling device was set so that it was removed at about 0.015 to 0.05 μm / sec. This output setting needs to be set to an optimum value according to the material of the adjustment electrode. Then, only the adjustment electrodes 25 and 26 and the thickened portion 31 of the insulating film adjacent to the adjustment electrode are milled simultaneously. Therefore, towards the adjustment electrodes 25, 26 made of silver material as compared with the insulating film 3 made of SiO ₂ (silicon oxide) is milled in an extremely high removal rate state, the insulating film 3 made of SiO ₂ (silicon oxide) The lower excitation electrodes 23 and 24 are not removed unnecessarily. In addition, by milling only the thickness-increasing portion 31 of the insulating film 3 made of SiO ₂ (silicon oxide), it is difficult to generate the electrode exposure area, and the metal material or the like from the adjustment electrode to the excitation electrode is scattered. However, the short circuit does not cause oscillation stop. In addition, since the milling region can be expanded not only to the adjustment electrodes 25 and 26 but also to the thick insulating film portion 31, the tolerance of the holder for holding the piezoelectric vibrating piece and the mask member can be given a margin. The adverse effect of deviation can be reduced. Since the tolerance of the holder and the mask member can be given a margin, the opening of the mask member can be enlarged, and as a result, the frequency adjustment efficiency is not lowered by the deviation of the milling region from the adjustment electrode. . Furthermore, when dry etching is performed in a single state or a wafer state before the piezoelectric vibrating piece is mounted on the package, the frequency can be adjusted without a mask member according to the output state of the dry etching. When an insulating film other than SiO ₂ (silicon oxide) is used, it is necessary to select one having a low removal rate with respect to the adjustment electrode.

In the above embodiment, a tuning fork type crystal vibrating piece is applied as the piezoelectric vibrating piece. However, the present invention is not limited to the AT-cut quartz vibrating piece, the GT-cut quartz vibrating piece, the crystal vibrating piece, and other ceramic vibrating pieces. The present invention can also be applied to a piezoelectric vibrator using the piezoelectric vibrating piece. In addition, although SiO ₂ is taken as an example of the insulating film, SiO or other insulating oxide films can be used. As an example of dry etching, milling is used as an example. However, plasma etching, dry etching using reactive gas ions, or the like may be used.

  The present invention can be implemented in various other forms without departing from the spirit or main features thereof, and should not be interpreted in a limited manner. The scope of the present invention is indicated by the claims, and is not limited by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

The top view which shows the crystal wafer which concerns on this form. The figure which showed typically the tuning fork type crystal vibrating piece of the crystal wafer of FIG. Sectional drawing along the AA line of FIG. Sectional drawing along the BB line of FIG. Sectional drawing along CC line of FIG. Sectional drawing which shows the other form of this invention. The top view which shows the mask which concerns on this form.

Explanation of symbols

1 Quartz wafer 2 Tuning fork type crystal vibrating piece (piezoelectric vibrating piece)
3 Insulating film

Claims (7)

The piezoelectric vibrating piece is configured to have an adjustment electrode whose frequency is adjusted by increasing / decreasing the mass of the electrode made of a metal material, and a different polarity from the adjustment electrode through the non-electrode region from the adjustment electrode. An excitation electrode,
An insulating film is formed on the electrodeless region and the excitation electrode,
A piezoelectric vibrating piece, wherein an insulating film in the vicinity of an electrodeless region including a boundary portion between the electrodeless region and the excitation electrode is formed thicker than other regions. In a piezoelectric vibrating piece comprising a base and a plurality of legs protruding from the base,
Each leg has
An adjustment electrode formed at the tip of the leg main surface, the frequency of which is adjusted by increasing / decreasing the mass of the electrode made of a metal material, and the leg main from the adjustment electrode via the first electrodeless region A main surface central excitation electrode formed in the center of the surface and configured to have a different polarity from the adjustment electrode, and formed close to the ridge of the leg portion from the main surface central excitation electrode via a second electrodeless region An end excitation electrode,
An insulating film is formed on top of the first electrodeless region, the main surface central excitation electrode, and the second electrodeless region;
A piezoelectric vibrating piece, wherein an insulating film in the vicinity of the first electrodeless region including a boundary between the first electrodeless region and the main surface central excitation electrode is formed thicker than other regions. 3. The piezoelectric vibrating piece according to claim 1, wherein a thickness of the insulating film not formed on the thick film is set to 0.005 μm to 0.03 μm. 3. The piezoelectric vibrating piece according to claim 2, wherein a groove portion is formed on a main surface of the leg portion, and a portion of the main surface central excitation electrode is formed inside the groove portion. The piezoelectric vibrating piece according to any one of claims 1 to 4, wherein the piezoelectric vibrating piece is made of quartz and the insulating film is made of silicon oxide. A piezoelectric vibrator comprising the piezoelectric vibrating piece according to any one of claims 1 to 5. A method for adjusting the frequency of a piezoelectric vibrating piece according to any one of claims 1 to 5,
A method of adjusting a frequency of a piezoelectric vibrating piece, characterized by simultaneously dry-etching only the adjustment electrode and a thick insulating film portion adjacent to the adjustment electrode.

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