JP2008085768A - Tuning fork type crystal vibration element and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tuning fork type crystal vibration element which can be readily adjusted to a proper frequency, even if frequency dispersion is generated during wafer processing, and to provide a manufacturing method therefor. <P>SOLUTION: The tuning fork type crystal vibration element has a plurality of groove portions 3 or a plurality of recessed portions 5, formed on the arm tip portions and also has metal coatings 4 and 6 for frequency adjustment formed in the groove portions 3 or recessed portions 5. In particular, the tuning fork type crystal vibration element has, the frequency characteristics prior to the metal coatings 4 and 6 are formed, all being set higher than the desired frequency and also having the frequency characteristics, all being set lower than the desired frequency by forming the metal coatings 4 and 6, and being adjusted to the desired frequency by grinding the metal coatings 4 and 6. The manufacturing method therefor is also provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a tuning fork type crystal resonator element and a method for manufacturing the same, and more particularly to a tuning fork type crystal resonator element that can be easily adjusted to an appropriate frequency even when a frequency variation occurs in wafer processing.

A conventional tuning fork type crystal vibrating element will be described with reference to FIG. FIG. 9 is an explanatory plan view of a conventional tuning-fork type crystal vibrating element.
As shown in FIG. 9, the conventional tuning fork type crystal vibrating element basically includes a base portion 11 and two arm portions 12 and 13.
In the tuning fork type crystal resonator element, a metal electrode film is formed after processing the crystal substrate into the shape shown in FIG.

In the base 11, metal electrode films 11a and 11b are formed on a quartz substrate.
The arm portions 12 and 13 are formed so as to protrude from the base portion 11, and groove portions 12 a and 13 a are formed on the side close to the base portion 11. The grooves 12a and 13a have grooves formed on the surfaces and are covered with a metal film.

At the tips of the arms 12 and 13 are formed crystal exposed portions 12b and 13b in which no electrodes are formed, and adjustment electrodes 12c and 13c for frequency adjustment, following the grooves 12a and 13a.
Specifically, the adjustment electrodes 12c and 13c are formed by laminating a chromium (Cr) film and a gold (Au) film, connected to a resonance circuit to resonate, and measuring the frequency to determine the Au of the adjustment electrodes 12c and 13c. The film is removed by laser irradiation, and the frequency of the entire vibration element is adjusted.

  As related prior arts, there are JP-A-2003-133895 (Patent Document 1), JP-A-2004-120249 (Patent Document 2), and JP-A 2000-065992 (Patent Document 3).

  Patent Document 1 solves the problem that the frequency adjustment electrode is divided into the coarse adjustment electrode and the fine adjustment electrode, and the laser irradiation passes through the front electrode and removes it to the back electrode in the fine adjustment electrode. For this purpose, a plurality of fine tuning electrodes are provided at regular intervals, and vibrating pieces formed alternately so that the electrode position on the back surface and the electrode position on the front surface do not overlap are shown.

  In Patent Document 2, the metal film formed on the tip of the arm part is irradiated with laser light to partially evaporate the metal film to adjust the frequency. However, the area of the excitation electrode is reduced due to this metal film. In order to prevent the decrease, there is shown a piezoelectric vibrating piece in which an island-like or peninsular region is formed in a groove provided in an arm portion and a metal film is provided on the surface thereof.

  Patent Document 3 discloses that in an ultrasonic microphone, the resonance frequency can be adjusted by forming a plurality of slits on the outer periphery.

JP 2003-133895 A JP 2004-120249 A JP 2000-069592 A

  However, in the above conventional tuning fork type quartz vibrating element, in order to adjust the frequency variation generated in the wafer processing step, the frequency adjusting electrode is irradiated with a laser to scrape the electrode. In order to make significant adjustments, it is necessary to scrape many electrode parts, and it is necessary that a sufficient metal film is laminated as an electrode, and if the frequency adjustment electrode must be thick enough, the structure and manufacturing There was a problem that became complicated.

Patent Documents 1 and 2 are basically the same as the above-described conventional tuning fork type crystal vibrating element, and use a method of scraping the frequency adjusting electrode formed on the arm portion. In particular, in Patent Documents 1 and 2, if a thick electrode is formed on the surface of the element, the frequency characteristics are greatly affected. Therefore, a thin electrode film is formed and scraped to a certain extent. Due to the area limitation, the frequency adjustment range cannot be widened.
Further, Patent Document 3 merely shows a microphone that performs frequency adjustment using a plurality of slits.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a tuning-fork type crystal vibrating element that can be easily adjusted to an appropriate frequency even when a frequency variation occurs in wafer processing, and a method for manufacturing the same.

  According to the present invention for solving the problems of the conventional example described above, in the tuning fork type crystal resonator element, one or a plurality of groove-shaped grooves are formed at the tip of the arm, and a metal film for frequency adjustment is formed at the groove. It is characterized by that.

  The present invention is characterized in that, in a tuning fork type crystal resonator element, one or a plurality of groove-shaped grooves are formed on both surfaces of an arm tip, and a metal film for frequency adjustment is formed on the grooves.

  The present invention is characterized in that, in the tuning fork type crystal resonator element, the thickness of the metal coating is 1 μm or less.

  The present invention is characterized in that, in the tuning fork type crystal resonator element, the groove has a length of 500 μm and a width of 10 to 90 μm.

  The present invention is characterized in that, in the tuning fork type crystal resonator element, the groove portion has a length of 300 μm and a width of 10 to 90 μm near the tip of the arm.

  The present invention is characterized in that, in a tuning fork type crystal resonator element, a plurality of concave recesses are formed at an arm tip, and a metal film for frequency adjustment is formed in the recess.

  The present invention is characterized in that, in a tuning fork type crystal resonator element, a plurality of concave recesses are formed on both surfaces of an arm tip, and a metal film for frequency adjustment is formed in the recesses.

  The present invention is characterized in that, in the tuning fork type crystal resonator element, the concave portion has a diameter of 10 to 90 μm.

  The present invention is characterized in that, in a method for manufacturing a tuning fork type crystal resonator element, one or a plurality of groove-shaped grooves are formed at an arm tip, and a metal film is formed on the groove.

  The present invention provides a method for manufacturing a tuning fork type crystal resonator element, wherein one or a plurality of groove-shaped grooves are formed on one surface of an arm tip, and one or a plurality of groove-shaped grooves are formed on the other surface of the arm. It is formed so as to be opposed to the groove portion formed on the surface, and a metal film is formed in the groove portion.

  In the method for manufacturing a tuning fork type crystal resonator element, the present invention is characterized in that a plurality of concave recesses are formed at an arm tip, and a metal film is formed in the recesses.

  According to the present invention, in a method for manufacturing a tuning fork type crystal resonator element, a plurality of concave recesses are formed on one surface of an arm tip, and a plurality of concave recesses are formed on one surface of the arm. And forming a metal film on the concave portion.

  The present invention provides a method for manufacturing a tuning fork type crystal resonator element as described above, with respect to the frequency variation of the frequency characteristic generated in the wafer process in the state of the element before the metal film for frequency adjustment is formed. The frequency of the tuning-fork type crystal resonator element is manufactured by forming a metal film on the groove-shaped groove or the concave-shaped groove provided at the tip of the arm. All the characteristic frequencies are made lower than the desired frequency, and the metal film formed in the groove or recess is shaved with an ion beam and adjusted to the desired frequency.

  The present invention is characterized in that in the tuning fork type crystal resonator, the tuning fork type crystal resonator element is housed in a package.

  The present invention is characterized in that in the crystal oscillator, the tuning fork type crystal resonator element and the integrated circuit are housed in a package.

  According to the present invention, the tuning fork-type crystal resonator element in which one or a plurality of groove-shaped grooves are formed at the tip of the arm and the frequency-adjusting metal coating is formed on the groove is easy to achieve frequency variation at an appropriate frequency. There is an effect that can be adjusted.

  According to the present invention, one or a plurality of groove-shaped groove portions are formed on both surfaces of the arm tip, and the tuning-fork type crystal resonator element in which a metal film for frequency adjustment is formed in the groove portion, the frequency variation is set to an appropriate frequency. There is an effect that can be easily adjusted.

  According to the present invention, a tuning fork type crystal resonator element in which a plurality of concave recesses are formed at the tip of the arm and a metal film for frequency adjustment is formed in the recesses, so that frequency variation can be easily adjusted to an appropriate frequency. There is an effect that can be done.

  According to the present invention, a tuning fork-type crystal resonator element in which a plurality of concave recesses are formed on both surfaces of the arm tip and a metal film for frequency adjustment is formed in the recesses, so that frequency variation can be easily set to an appropriate frequency. There is an effect that can be adjusted.

  According to the present invention, the tuning fork-type crystal resonator element is manufactured by forming one or a plurality of groove-shaped grooves on the tip of the arm and forming a metal film on the groove. Therefore, the frequency variation can be easily adjusted to an appropriate frequency. There is an effect that can be adjusted.

  According to the present invention, one or a plurality of groove-shaped grooves are formed on one surface of the arm tip, and one or a plurality of groove-shaped grooves are formed on the other surface of the arm. Thus, the tuning fork-type crystal resonator element is formed by forming a metal film in the groove portion, so that the frequency variation can be easily adjusted to an appropriate frequency.

  According to the present invention, since the manufacturing method of the tuning fork type crystal resonator element in which a plurality of concave recesses are formed at the distal end of the arm and a metal film is formed in the recesses, the frequency variation can be easily adjusted to an appropriate frequency. effective.

  According to the present invention, a plurality of concave recesses are formed on one surface of the arm tip, and a plurality of concave recesses are formed on the other surface of the arm opposite to the recesses formed on one surface. The method of manufacturing a tuning-fork type crystal vibrating element in which a metal film is formed in the concave portion has an effect that the frequency variation can be easily adjusted to an appropriate frequency.

  According to the present invention, with respect to the frequency variation of the frequency characteristics generated in the wafer process in the state of the element before the metal film for frequency adjustment is formed, the lowest frequency among the frequencies with the variation is desired. The frequency characteristics of the tuning-fork type crystal resonator element are all made higher than the desired frequency by forming a metal film in the groove-shaped groove portion or the concave portion provided at the tip of the arm. The tuning fork type crystal resonator element is manufactured by adjusting the frequency to a desired frequency by cutting the metal film formed on the groove or recess with an ion beam, so that all the tuning fork type crystal resonator elements with variations are There is an effect that can be adjusted.

[Summary of Invention]
Embodiments of the present invention will be described with reference to the drawings.
In the first tuning-fork type crystal resonator element and the method for manufacturing the same according to the embodiment of the present invention, one or a plurality of groove-shaped grooves are formed at the arm tip, and a metal film for frequency adjustment is formed at the groove. Thus, the frequency variation in wafer processing can be easily adjusted to an appropriate frequency.
In particular, the groove is formed on both sides of the arm tip, the length is about 300 to 500 μm, the width is about 10 to 90 μm, and the thickness of the metal coating is 1 μm or less.

Further, in the second tuning-fork type crystal resonator element and the manufacturing method thereof according to the embodiment of the present invention, a plurality of concave recesses are formed at the arm tip, and a metal film for frequency adjustment is formed in the recess. Thus, the frequency variation in wafer processing can be easily adjusted to an appropriate frequency.
In particular, the recess is formed on both surfaces of the arm tip, and the shape of the recess is 10 to 90 μm in diameter.

  The method for manufacturing a tuning-fork type crystal resonator element according to an embodiment of the present invention is the above-described manufacturing method, in the state of the element before the metal film for frequency adjustment is formed, in the frequency characteristic frequency generated in the wafer process. Regarding the variation, the tuning fork type is manufactured by forming the metal film in the groove-shaped groove or the concave-shaped recess at the tip of the arm in advance so that the lowest frequency among the frequencies with the variation is higher than the desired frequency. All tuning fork-type quartz crystals are made by adjusting the frequency of the frequency characteristics of the crystal resonator element to be lower than the desired frequency and adjusting the desired frequency by scraping the metal film formed in the groove or recess with an ion beam. The vibration element can be adjusted to an appropriate frequency.

[First Embodiment]
A first tuning-fork type crystal vibrating element according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of a first tuning-fork type crystal vibrating element according to an embodiment of the present invention.
As shown in FIG. 1, the first tuning-fork type crystal vibrating element (first element) according to the embodiment of the present invention basically includes a base 11 and two arm parts 12 and 13. Has been.
The first element forms a metal electrode film after processing the quartz substrate into the shape shown in FIG.

As the quartz substrate, for example, a Z-cut quartz plate having a thickness of 100 μm to 150 μm is used.
In the base 11, metal electrode films 11a and 11b are formed on a quartz substrate.
The arm portions 12 and 13 are formed so as to protrude from the base portion 11, and groove portions 12 a and 13 a are formed on the side close to the base portion 11. The grooves 12a and 13a are covered with a metal film.

At the tips of the arms 12 and 13 are formed crystal exposed portions 12b and 13b in which no electrodes are formed, and adjustment electrodes 12c and 13c for frequency adjustment, following the grooves 12a and 13a.
Specifically, the adjustment electrodes 12c and 13c are formed by laminating a chromium (Cr) film and a gold (Au) film.
The arm portions 12 and 13 resonate when the electrode films 11a and 11b are connected to a resonance circuit.

In particular, the shape of the adjustment electrodes 12c and 13c at the tip of the arm part is such that a groove part (slit shape) is formed in the longitudinal direction of the arm part, and a chromium (Cr) film and gold (Au) are formed in the groove part. A metal film such as a film is embedded.
The metal film is a weight adjusting film and plays the role of a metal film for frequency adjustment.
In the example of FIG. 1, two groove portions are provided on one side of one arm portion, and similarly, two groove portions are provided on the back surface.

  For example, the groove portion has a length of about 300 to 500 μm and a width of about 10 to 90 μm, and the thickness of the metal coating is 1 μm or less. The length of the groove is desirably about 300 μm.

In the first element, a quartz crystal substrate is processed into a tuning fork type by machining, photolithography / etching, or the like, and then an electrode material is formed and patterned using an apparatus such as vacuum deposition or sputtering.
FIG. 2 is a cross-sectional explanatory view of the portion corresponding to the adjustment electrodes 12c and 13c before forming the groove (step 1). FIG. 2 is an explanatory cross-sectional view before forming the groove.
As shown in FIG. 2, the quartz substrate 1 is covered with a metal film 2 as an electrode material. Here, the metal film 2 is formed by first forming a Cr film on a quartz substrate and forming an Au film thereon.

Next, groove portions for frequency adjustment are formed on the front and back by photolithography / etching or the like in portions corresponding to the adjustment electrodes 12c and 13c at the tip of the arm portion.
FIG. 3 is an explanatory cross-sectional view of the portion corresponding to the adjustment electrodes 12c and 13c after the formation of the groove (step 2). FIG. 3 is an explanatory cross-sectional view after forming the groove.
As shown in FIG. 3, the groove 3 is formed deeper than the thickness of the metal film 2 and into the quartz substrate 1.

Next, in a portion corresponding to the adjustment electrodes 12c and 13c, a weight metal film 4 is formed in the groove portion using a metal mask or the like.
FIG. 4 is a cross-sectional explanatory view after the metal film is formed on the portion corresponding to the adjustment electrodes 12c and 13c (step 3). FIG. 4 is an explanatory cross-sectional view after the metal film is formed.
As shown in FIG. 4, a metal film 4 for weight is formed in the groove portion 3. The thickness of the metal coating 4 is approximately the same as the depth of the groove 3. Thus, the weight electrode can be formed without increasing the thickness of the portion corresponding to the adjustment electrodes 12c and 13c.

The above manufacturing process is realized by a wafer process.
The tuning fork type quartz crystal resonator element formed in the wafer process before the metal coating 4 is formed is assumed to have a frequency variation, and the frequency characteristic has a desired frequency (nominal frequency) as the lowest frequency. (Frequency: 32768 Hz), and the metal film 4 is formed in the groove portion 3 so that the frequency characteristics of the tuning fork type crystal resonator element are all lower than the nominal frequency.

That is, before the metal coating 4 is formed, the frequency characteristics of all tuning fork type crystal vibrating elements are higher than the nominal frequency, and after the metal coating 4 is formed, the frequency characteristics of all tuning fork type crystal vibrating elements are the same. It is manufactured to be lower than the nominal frequency.
In order to lower the frequency characteristics, the depth of the groove 3 and the thickness of the metal coating 4 for the weight are adjusted, and the appropriate depth of the groove 3 and the thickness of the metal coating 4 for the weight are specified.
As a result, all tuning fork type crystal resonator elements manufactured in the wafer process have frequency characteristics lower than the nominal frequency.

Thereafter, the tuning fork type quartz resonator element cut out from the wafer is subjected to a process of scraping the surface of the metal film 4 portion with a mask or the like by an ion beam energy in an argon gas atmosphere to adjust the frequency characteristics.
That is, since the tip of the arm portion can be lightened by cutting the metal coating 4, the frequency of the frequency characteristics can be increased, and the frequency can be set higher if the amount to be cut is increased. As a result, the frequency characteristics of the tuning fork type crystal resonator element can be adjusted to the nominal frequency.

Next, a second tuning-fork type crystal resonator element according to an embodiment of the present invention will be described with reference to FIG. FIG. 5 is a schematic configuration diagram of a second tuning-fork type crystal vibrating element according to the embodiment of the present invention.
As shown in FIG. 5, the second tuning-fork type crystal vibrating element (second element) according to the embodiment of the present invention basically includes a base 11 and two arm parts 12 and 13. Has been.

The second element is basically the same as the first element except that the second element is not a groove (slit) in the portion corresponding to the adjustment electrodes 12c 'and 13c' at the tip of the arm. Is provided with a metal coating for a weight in the recess.
The shape viewed from the plane of the recess may be circular or polygonal.
Further, it is desirable that the concave portion has a diameter of about 10 to 90 μm and a depth of 1 μm or less.

The manufacturing method of the second element is the same as the manufacturing method of the first element, and is the same until the metal film 2 of the electrode material is formed on the quartz substrate 1 and patterned.
FIG. 6 is a cross-sectional explanatory diagram of the portion corresponding to the adjustment electrodes 12c ′ and 13c ′ before the formation of the recess (step 1). FIG. 6 is an explanatory cross-sectional view before forming the recess.

Next, concave portions 5 for frequency adjustment are formed on the front and back sides by photolithography / etching or the like in portions corresponding to the adjustment electrodes 12c 'and 13c' at the tip of the arm portion.
FIG. 7 is an explanatory cross-sectional view of the portion corresponding to the adjustment electrodes 12c ′ and 13c ′ after the formation of the recesses (step 2). FIG. 7 is an explanatory cross-sectional view after forming the recess.
As shown in FIG. 7, the recess 5 is formed deeper than the thickness of the metal film 2 and into the quartz substrate 1.

Next, in a portion corresponding to the adjustment electrodes 12c ′ and 13c ′, the weight metal film 6 is formed in the concave portion using a metal mask or the like.
FIG. 8 is an explanatory cross-sectional view of the portion corresponding to the adjustment electrodes 12c ′ and 13c ′ after the metal film is formed (step 3). FIG. 8 is a cross-sectional explanatory view after the metal film is formed.
As shown in FIG. 8, a metal film 6 for weight is formed in the recess 5. The thickness of the metal coating 6 is approximately the same as the depth of the recess 5. Thereby, an electrode for a weight can be formed without increasing the thickness of the portion corresponding to the adjustment electrodes 12c ′ and 13c ′.
The above manufacturing process is realized by a wafer process.

The method for adjusting the adjustment electrodes 12c ′ and 13c ′ to the nominal frequency is the same method as described in the first element.
That is, before the metal coating 6 is formed, the frequency characteristics of all tuning fork type quartz vibrating elements are higher than the nominal frequency, and after the metal coating 6 is formed, the frequency characteristics of all tuning fork type quartz vibrating elements are the same. It is manufactured to be lower than the nominal frequency, and the metal film 6 is further shaved to adjust the frequency characteristics to the nominal frequency.

A tuning fork crystal unit is provided by housing a first element and a second element in a package.
The first element, the second element, and the integrated circuit are housed in a package to provide a crystal oscillator.

  According to the first element, the second element, and the tuning fork type crystal resonator and crystal oscillator incorporating the first element, the area of the frequency adjusting electrode is increased without increasing the thickness of the arm portion of the tuning fork type crystal vibration element. In addition, the range of frequency adjustment can be widened, and there is an effect that the frequency variation of elements in wafer processing can be easily adjusted.

  According to the manufacturing method of the first element and the second element, the frequency adjustment range is widened without increasing the arm area of the tuning fork type crystal vibrating element, without increasing the area of the frequency adjusting electrode. Thus, there is an effect that an element capable of easily adjusting the frequency variation of the element in wafer processing can be manufactured.

  The present invention is suitable for a tuning-fork type crystal vibrating element that can be easily adjusted to an appropriate frequency even if a frequency variation occurs in wafer processing, and a method for manufacturing the same.

1 is a schematic configuration diagram of a first tuning-fork type crystal vibrating element according to an embodiment of the present invention. It is sectional explanatory drawing before a groove part formation. It is explanatory drawing of a cross section after a groove part formation. It is sectional explanatory drawing after metal film film-forming. It is a schematic block diagram of the 2nd tuning fork type crystal vibrating element which concerns on embodiment of this invention. It is sectional explanatory drawing before a recessed part formation. It is sectional explanatory drawing after a recessed part formation. It is sectional explanatory drawing after metal film film-forming. It is a plane explanatory view of a conventional tuning fork type crystal resonator element.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Quartz substrate, 2 ... Metal film, 3 ... Groove part, 4 ... Metal film, 5 ... Recessed part, 6 ... Metal film, 11 ... Base part, 11a, 11b ... Electrode film, 12, 13 ... Arm part, 12a, 13a ... Groove part, 12b, 13b ... quartz exposed part, 12c, 13c, 12c ', 13c', 12c, 13c ... adjustment electrode

Claims (15)

  A tuning-fork type crystal vibrating element, wherein one or a plurality of groove-shaped grooves are formed at the tip of the arm, and a metal film for frequency adjustment is formed in the groove.   A tuning-fork type crystal vibrating element, wherein one or a plurality of groove-shaped grooves are formed on both surfaces of an arm tip, and a metal film for frequency adjustment is formed on the grooves.   The tuning-fork type crystal resonator element according to claim 1, wherein the thickness of the metal coating is 1 µm or less.   4. The tuning fork type crystal vibrating element according to claim 1, wherein the groove has a length of 500 [mu] m and a width of 10 to 90 [mu] m.   4. The tuning fork type crystal vibrating element according to claim 1, wherein the groove has a length of 300 [mu] m and a width of 10 to 90 [mu] m near the tip of the arm.   A tuning-fork type crystal vibrating element, wherein a plurality of concave recesses are formed at an arm tip, and a metal film for frequency adjustment is formed in the recesses.   A tuning-fork type crystal vibrating element, wherein a plurality of concave recesses are formed on both surfaces of an arm tip, and a metal film for frequency adjustment is formed in the recesses.   8. The tuning fork type quartz vibrating element according to claim 6, wherein the concave portion has a diameter of 10 to 90 [mu] m.   A manufacturing method of a tuning-fork type crystal resonator element, wherein one or a plurality of groove-shaped grooves are formed at an arm tip, and a metal film is formed on the grooves.   Forming one or more groove-shaped grooves on one surface of the arm tip, and forming one or more groove-shaped grooves on the other surface of the arm opposite to the groove formed on the one surface; A method for producing a tuning-fork type crystal resonator element, comprising forming a metal film in the groove.   A method for producing a tuning-fork type crystal resonator element, comprising: forming a plurality of concave recesses at an arm tip, and forming a metal film on the recesses.   A plurality of concave recesses are formed on one surface of the arm tip, and a plurality of concave recesses are formed on the other surface of the arm opposite to the recesses formed on the one surface. A method for producing a tuning-fork type crystal vibrating element, comprising forming a film.   Regarding the frequency variation of the frequency characteristics generated in the wafer process in the state of the element before the metal film for frequency adjustment is formed, the lowest frequency among the variations is higher than the desired frequency. The frequency characteristics of the tuning fork type crystal resonator element are all made lower than a desired frequency by forming a metal film in a groove-shaped groove or a concave-shaped recess provided at the tip of the arm, and the groove or 13. The method for manufacturing a tuning-fork type crystal vibrating element according to claim 9, wherein the metal film formed in the recess is shaved with an ion beam and adjusted to a desired frequency.   9. A tuning fork type crystal resonator comprising the tuning fork type crystal resonator element according to claim 1 housed in a package.   9. A crystal oscillator comprising the tuning fork type crystal resonator element according to claim 1 and an integrated circuit housed in a package.

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