JP2005151423A - Piezoelectric vibration chip and piezoelectric device and method of manufacturing them, and mobile telephone apparatus using piezoelectric device, and electronic apparatus using piezoelectric device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric vibration chip and a piezoelectric device of which the temperature characteristics are improved by reducing a change in a frequency deviation caused by a temperature change, a method of manufacturing them, a mobile telephone apparatus using the piezoelectric device, and an electronic apparatus using the piezoelectric device. <P>SOLUTION: The piezoelectric vibration chip has a base portion 51 and a plurality of vibrating arms 34, 35 extending in parallel from the base portion 51, the base portion 51 includes a slit 100, and first grooves 56A, 57A are formed on a front surface 200 of the vibrating arms 34, 35, second grooves 56B, 57B are formed on a rear surface 210 of the vibrating arms 34, 35, each of the grooves includes at least driving electrodes 54, 55, and the vibrating arms 34, 35 are formed asymmetric at the side of the front surface 200 and at the side of the rear surface 210 to dynamically unbalance the extension and shrinkage of the arms when electric power is supplied to the electrodes to vibrate the vibrating arms 34, 35. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a piezoelectric vibrating piece, a piezoelectric device, a manufacturing method thereof, and a mobile phone and an electronic apparatus using the piezoelectric device.

Piezoelectric resonator element in a package in small information devices such as HDD (Hard Disk Drive), mobile computer or IC (Integrated Circuit) card, and mobile communication devices such as mobile phone, car phone or paging system Piezoelectric devices such as crystal resonators and crystal oscillators that contain sapphire are widely used.
As a piezoelectric vibrating piece housed in a conventional piezoelectric device, a structure having a base and a pair of vibrating arms formed so as to protrude from the base is employed (see Patent Document 1).
A groove portion is formed on the front surface portion and the back surface portion of the vibrating arm of the conventional piezoelectric vibrating piece, and a notch portion is formed on the base portion.

JP 2002-261575 A (refer to pages 5 to 7 and FIG. 1)

However, the structure of the conventional piezoelectric vibrating piece is a so-called grooved tuning fork type vibrating piece. However, the position of the groove on the front surface side and the position of the groove on the back surface side of this conventional vibrating arm are symmetrical. Are arranged. That is, the center line of the groove portion on the front surface side that forms the outer shape of the vibrating arm and the center line of the groove portion on the back surface side are made to coincide. Because of the structure of such a piezoelectric vibrating piece, the temperature characteristic (frequency), which is the relationship of the change in frequency deviation with the change in temperature, shows a quadratic function curve. For this reason, there exists a problem that the change of the frequency deviation by the change of temperature will become large.
The present invention has been made in order to solve the above-described problems. A piezoelectric resonator element and a piezoelectric device having excellent temperature characteristics, a manufacturing method thereof, and a piezoelectric device are provided by reducing a change in frequency deviation with respect to a change in temperature. It is an object of the present invention to provide a mobile phone device using a device and an electronic apparatus using a piezoelectric device.

  According to the first aspect of the present invention, there is provided a plurality of vibrating arms extending in parallel from the base portion, the base portion is provided with a cut portion, and a surface portion of the vibrating arm is provided with a first portion. One groove portion is formed, a second groove portion is formed on the back surface portion of the vibrating arm, and at least the groove portion is provided with a driving electrode. The shape of the vibrating arm on the surface portion side and the vibrating arm The shape of the back surface side of the piezoelectric vibrating piece is formed asymmetrically so as to break a mechanical balance between expansion and contraction when the vibrating arm vibrates when the electrode is energized. Achieved.

According to the configuration of the first aspect of the invention, the shape on the front surface side of the vibrating arm and the shape on the back surface side of the vibrating arm are asymmetric so that the mechanical balance is lost when the vibrating arm is vibrated by energizing the electrodes. Is formed.
As a result, when the vibrating arm is vibrated by energizing the electrodes, there is a difference between the electric field generated on the front surface side of the vibrating arm and the electric field generated on the back surface side. Addition of the vibration component in the vertical direction causes an oblique movement with respect to the bending vibration and the vertical vibration. This makes it possible to obtain a flat portion in the temperature characteristic by suppressing the second-order coefficient of the temperature characteristic curve to be very small, and to reduce the change in frequency deviation due to the temperature change, thereby obtaining a piezoelectric vibrating piece having excellent temperature characteristics. It is done.

According to a second invention, in the configuration of the first invention, in the cross section intersecting with the longitudinal direction of the vibrating arm, the center line of the first groove portion and the center line of the second groove portion are shifted in opposite directions. It is characterized by being.
According to the configuration of the second invention, the center line of the first groove portion and the center line of the second groove portion are shifted in opposite directions.
As a result, when the vibrating arm is vibrated by energizing the electrodes, there is a difference between the electric field generated on the front surface side of the vibrating arm and the electric field generated on the back surface side. Addition of the vibration component in the vertical direction causes an oblique movement with respect to the bending vibration and the vertical vibration. This makes it possible to obtain a flat portion in the temperature characteristic by suppressing the second-order coefficient of the temperature characteristic curve to be very small, and to reduce the change in frequency deviation due to the temperature change, thereby obtaining a piezoelectric vibrating piece having excellent temperature characteristics. It is done.

According to a third invention, in the configuration of the first invention, the electrode includes an underlayer and an electrode layer formed on the underlayer, and the underlayer of the electrode on the surface portion side of the vibrating arm The thickness is different from the thickness of the base layer of the electrode on the back surface side of the vibrating arm.
According to the configuration of the third invention, the thickness of the base layer of the electrode on the surface side of the vibrating arm is different from the thickness of the base layer of the electrode on the back side of the vibrating arm.
As a result, there is a difference between the stress on the surface side of the vibrating arm and the stress on the back side caused by the base film when the vibrating arm is vibrated by energizing the electrode. A vibration component in the vertical direction is added to the vibration, and an oblique movement occurs. This makes it possible to obtain a flat portion in the temperature characteristic by suppressing the second-order coefficient of the temperature characteristic curve to be very small, and to reduce the change in frequency deviation due to the temperature change, thereby obtaining a piezoelectric vibrating piece having excellent temperature characteristics. It is done.

A fourth invention is characterized in that, in the configuration of the third invention, the underlayer is made of Cr and the electrode layer is made of Au.
According to the configuration of the fourth invention, the base layer is Cr and the electrode layer is Au.
As a result, Cr is used as the underlayer, so Cr is a suitable film as the underlayer of the piezoelectric vibrating piece, and the temperature characteristics are improved by the influence of stress generated by the formation of the Cr film.

  According to a fifth aspect of the present invention, there is provided a piezoelectric device in which a piezoelectric vibrating piece is accommodated in a package, wherein the piezoelectric vibrating piece has a base and a plurality of vibrating arms extending in parallel from the base. The base has a notch, the vibrating arm has a first groove, the back of the vibrating arm has a second groove, and at least the groove has a driving groove. The shape of the vibrating arm on the surface portion side and the shape of the vibrating arm on the back surface portion side are the dynamics of extension and contraction when the vibrating arm vibrates when the electrode is energized. This is achieved by a piezoelectric device characterized by being formed asymmetrically so as to break the balance.

According to the configuration of the fifth aspect of the invention, the shape on the front surface side of the vibrating arm and the shape on the back surface side of the vibrating arm are asymmetric so as to break the mechanical balance when the vibrating arm is vibrated by energizing the electrodes. Is formed.
As a result, when the vibrating arm is vibrated by energizing the electrodes, there is a difference between the electric field generated on the front surface side of the vibrating arm and the electric field generated on the back surface side. Addition of the vibration component in the vertical direction causes an oblique movement with respect to the bending vibration and the vertical vibration. As a result, the second-order coefficient of the temperature characteristic curve is suppressed to a very small level, a flat portion is obtained in the temperature characteristic, the change in frequency deviation due to a temperature change can be reduced, and a piezoelectric device having excellent temperature characteristics can be obtained. .

  According to the sixth aspect of the present invention, the object has a base and a plurality of vibrating arms extending in parallel from the base, and the base is provided with a notch, and the surface of the vibrating arm is provided. A method of manufacturing a piezoelectric vibrating piece in which a first groove portion is formed in a portion, a second groove portion is formed in a back surface portion of the vibrating arm, and a piezoelectric vibrating piece including a driving electrode is formed at least in the groove portion. In the outer shape etching step of forming an outer shape by etching a substrate made of a piezoelectric material, the shape on the surface portion side of the vibrating arm and the shape on the back surface portion side of the vibrating arm are energized to the electrode to This is achieved by a method of manufacturing a piezoelectric vibrating piece, wherein the vibrating arm is formed asymmetrically so as to break a mechanical balance between expansion and contraction when vibrating.

According to the configuration of the sixth invention, in the outer shape etching step, the outer shape is formed by etching the substrate made of the piezoelectric material. In this outer shape etching process, the shape of the surface side of the vibrating arm and the shape of the back surface side of the vibrating arm are formed asymmetrically so as to break the mechanical balance when the vibrating arm vibrates when the electrode is energized. .
As a result, when the vibrating arm is vibrated by energizing the electrodes, there is a difference between the electric field generated on the front surface side of the vibrating arm and the electric field generated on the back surface side. Addition of the vibration component in the vertical direction causes an oblique movement with respect to the bending vibration and the vertical vibration. This makes it possible to obtain a flat portion in the temperature characteristic by suppressing the second-order coefficient of the temperature characteristic curve to be very small, and to reduce the change in frequency deviation due to the temperature change, thereby obtaining a piezoelectric vibrating piece having excellent temperature characteristics. It is done.

  According to a seventh aspect of the present invention, the object has a base and a plurality of vibrating arms extending in parallel from the base, and the base is provided with a notch, and the surface of the vibrating arm is provided. A method of manufacturing a piezoelectric device in which a first groove portion is formed in a portion, a second groove portion is formed in a back surface portion of the vibrating arm, and a piezoelectric vibrating piece having a driving electrode in at least the groove portion is accommodated in a package In the outer shape etching step of forming an outer shape by etching a substrate made of a piezoelectric material, the shape of the vibrating arm on the front surface side and the shape of the vibrating arm on the back surface side are energized to the electrode. In addition, the piezoelectric device is manufactured by a method of manufacturing the piezoelectric device, wherein the piezoelectric device is formed asymmetrically so as to break a mechanical balance between expansion and contraction when the vibrating arm vibrates.

According to the configuration of the seventh invention, in the outer shape etching step, the outer shape is formed by etching the substrate made of the piezoelectric material. In this outer shape etching process, the shape of the surface side of the vibrating arm and the shape of the back surface side of the vibrating arm are formed asymmetrically so as to break the mechanical balance when the vibrating arm vibrates when the electrode is energized. .
As a result, when the vibrating arm is vibrated by energizing the electrodes, there is a difference between the electric field generated on the front surface side of the vibrating arm and the electric field generated on the back surface side. Addition of the vibration component in the vertical direction causes an oblique movement with respect to the bending vibration and the vertical vibration. As a result, the second-order coefficient of the temperature characteristic curve is suppressed to a very small level, a flat portion is obtained in the temperature characteristic, the change in frequency deviation due to a temperature change can be reduced, and a piezoelectric device having excellent temperature characteristics can be obtained. .

  According to an eighth aspect of the present invention, there is provided a mobile phone device in which a control clock signal is obtained by a piezoelectric device having a piezoelectric vibrating piece accommodated in a package, wherein the piezoelectric vibrating piece includes a base and A plurality of vibrating arms extending in parallel from the base portion, the base portion is provided with a cut portion, and a first groove portion is formed on the surface portion of the vibrating arm, and the back surface portion of the vibrating arm. The second groove portion is formed, and at least the groove portion is provided with a driving electrode, and the shape of the vibrating arm on the surface portion side and the shape of the vibrating arm on the back surface portion side are the electrodes. This is achieved by a mobile phone device that is formed asymmetrically so as to break a dynamic balance between expansion and contraction when the vibrating arm vibrates.

According to the configuration of the eighth invention, the shape of the surface side of the vibrating arm and the shape of the back side of the vibrating arm are asymmetric so as to break the mechanical balance when the vibrating arm is vibrated by energizing the electrodes. Is formed.
As a result, when the vibrating arm is vibrated by energizing the electrodes, there is a difference between the electric field generated on the front surface side of the vibrating arm and the electric field generated on the back surface side. Addition of the vibration component in the vertical direction causes an oblique movement with respect to the bending vibration and the vertical vibration. As a result, the second-order coefficient of the temperature characteristic curve is suppressed to a very low level, and a flat portion is obtained in the temperature characteristic, so that the change in frequency deviation due to the temperature change can be reduced, and an excellent temperature characteristic can be obtained.

  According to the ninth aspect of the present invention, there is provided an electronic apparatus in which a clock signal for control is obtained by a piezoelectric device having a piezoelectric vibrating piece accommodated in a package, wherein the piezoelectric vibrating piece includes a base, A plurality of resonating arms extending in parallel from the base, wherein the base is provided with a notch, a first groove is formed on the surface of the resonating arm, and a back surface of the resonating arm is formed. Has a second groove portion, and at least the groove portion is provided with a driving electrode, and the shape of the vibration arm on the front surface side and the shape of the vibration arm on the back surface side are formed on the electrode. This is achieved by an electronic device that is formed asymmetrically so as to break a mechanical balance between expansion and contraction when the vibrating arm vibrates when energized.

According to the configuration of the ninth aspect of the invention, the shape of the surface side of the vibrating arm and the shape of the back side of the vibrating arm are asymmetric so as to break the mechanical balance when the vibrating arm is vibrated by energizing the electrodes. Is formed.
As a result, when the vibrating arm is vibrated by energizing the electrodes, there is a difference between the electric field generated on the front surface side of the vibrating arm and the electric field generated on the back surface side. Addition of the vibration component in the vertical direction causes an oblique movement with respect to the bending vibration and the vertical vibration. As a result, the second-order coefficient of the temperature characteristic curve is suppressed to a very low level, and a flat portion is obtained in the temperature characteristic, so that the change in frequency deviation due to the temperature change can be reduced, and an excellent temperature characteristic can be obtained.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Preferred embodiments of the invention will be described below with reference to the drawings.
1 and 2 show an embodiment of a piezoelectric device of the present invention. FIG. 1 is a schematic plan view thereof, and FIG. 2 is a schematic cross-sectional view taken along the line BB of FIG.
1 and 2 show an example in which the piezoelectric device 30 is a crystal resonator. The piezoelectric device 30 houses a piezoelectric vibrating piece 32 in a package 36. The package 36 is formed, for example, by laminating a plurality of substrates formed by molding an aluminum oxide ceramic green sheet as an insulating material, and then sintering. Each of the plurality of substrates is formed with a predetermined hole on the inner side thereof, so that a predetermined internal space S2 is formed on the inner side when stacked.
This internal space S2 is a housing space for housing the piezoelectric vibrating piece.
That is, as shown in FIG. 2, in this embodiment, the package 36 is formed by, for example, stacking the first laminated substrate 61, the second laminated substrate 64, and the third laminated substrate 68 from below. ing.

In the inner space S2 of the package 36, in the vicinity of the left end portion, the second laminated substrate 64 that is exposed to the inner space S2 and constitutes the inner bottom portion has, for example, an electrode formed by nickel plating and gold plating on tungsten metallization. Portions 31, 31 are provided.
The electrode portions 31 are connected to the outside to supply a driving voltage. Conductive adhesives 43, 43 are applied on the electrode portions 31, 31, and the base 51 of the piezoelectric vibrating piece 32 is placed on the conductive adhesives 43, 43. 43 are hardened. In addition, as the conductive adhesives 43 and 43, a synthetic resin agent as an adhesive component exhibiting bonding strength can be used which contains conductive particles such as silver fine particles. A system-based or polyimide-based conductive adhesive or the like can be used.

The piezoelectric vibrating piece 32 shown in FIGS. 1 and 2 is formed by, for example, crystal etching as a piezoelectric material by a manufacturing process described later. In this embodiment, the piezoelectric vibrating piece 32 is formed in a small size. In order to obtain the required performance, the shape is particularly shown in the schematic perspective view of FIG.
3 has a base 51 fixed to the package 36 side shown in FIGS. 1 and 2, and a base 51 as a base end, which is divided into two forks toward the left in the figure. A pair of vibrating arms 34 and 35 extending in parallel along the mechanical axis) is provided. As the piezoelectric vibrating piece 32, a so-called tuning fork type piezoelectric vibrating piece whose shape is entirely like a tuning fork is used. The pair of vibrating arms 34 and 35 is an example of a plurality of vibrating arms. FIG. 3 shows the X direction (electric axis), the Y direction (mechanical axis), and the Z direction (optical axis).

  The vibrating arms 34 and 35 of the piezoelectric vibrating piece 32 shown in FIG. 3 have long bottomed first groove portions 57 (57A) and 56 (56A) and second groove portions 57 (extending in the length direction (Y direction), respectively. 57B) and 56 (56B) are formed. The first groove portions 57 (57A) and 56 (56A) and the second groove portions 57 (57B) and 56 (56B) are as shown in FIG. 4 which is a sectional view taken along the line CC of FIG. Each of the vibrating arms 34 and 35 is formed on both the front and back surfaces. The vibrating arms 34 and 35 have a substantially H-shaped cross section.

In FIG. 3, lead electrodes 52 and 53 are formed near both ends in the width direction of the end portion (right end portion in FIG. 3) of the base portion 51 of the piezoelectric vibrating piece 32. The lead electrodes 52 and 53 are similarly formed on the back surface (not shown) of the base 51 of the piezoelectric vibrating piece 32.
These lead electrodes 52 and 53 are portions connected to the package-side electrode portions 31 and 31 shown in FIG. 1 by the conductive adhesives 43 and 43 as described above. The lead electrodes 52 and 53 are electrically connected to excitation electrodes (drive electrodes) 54 and 55 provided in the grooves 56 and 57 of the vibrating arms 34 and 35 as shown in the drawing. Yes.

  Moreover, each excitation electrode 54 and 55 is also formed in the both sides | surfaces of each vibration arm 34 and 35, as FIG. 4 shows, for example, regarding the vibration arm 34, the 1st groove part 57 (57A). The excitation electrode 54 in the second groove portion 57 (57B) and the excitation electrode 55 on the side surface portion are made to have different polarities. With respect to the vibrating arm 35, the excitation electrode 55 in the first groove portion 56 (56A) and the second groove portion 56 (56B) and the excitation electrode 54 on the side surface portion thereof have different polarities.

As understood with reference to FIGS. 3 and 4, the side electrode portions 54 a and 55 a formed on the inner side surfaces of the vibrating arm 34 and the vibrating arm 35 facing each other have different polarities.
The piezoelectric vibrating piece 32 shown in FIG. 3 is formed of, for example, quartz that oscillates at approximately 30 KHz to approximately 40 KHz.

Here, a dimension example in the shape of the miniaturized piezoelectric vibrating piece 32 shown in FIG. 3 will be described.
The length L1 in the longitudinal direction of the pair of vibrating arms 34 and 35 shown in FIG. 3 is, for example, 1.644 mm. A length L2 of the base 51 in the Y direction is 0.56 mm.
The base 51 has notches 100 and 100 on both sides thereof. A length L3 from the notch 100 to the vicinity of the other end of the base 51 is, for example, 0.113 mm.
The width W of the vibrating arms 34 and 35 shown in FIG. 3 is preferably in the range of 50 μm to 150 μm. The width W of the vibrating arms 34 and 35 is, for example, 0.1 mm. The thickness D of the vibrating arms 34 and 35 is, for example, 0.1 mm.

The groove width E of the first groove portions 57A and 56A and the second groove portions 57B and 56B in FIG. 3 is 40% or more as compared with the width W of the vibrating arms 35 and 34. The groove depth G of the first groove portions 57A and 56A and the second groove portions 57B and 56B is preferably 30% or more and less than 50% with respect to the thickness D of the vibrating arms 34 and 35. The groove width E being preferably 40% or more of the width W of the vibrating arm is a condition for reducing the rigidity of the vibrating arms 34 and 35.
The groove depth G is preferably 30% to less than 50% of the thickness D of the vibrating arms 34 and 35, which is a condition for reducing the rigidity of the vibrating arms 34 and 35. If the groove depth G is 50% or more, the front surface side groove and the back surface side groove are connected.
The reason why the first groove portions 57A and 56A and the second groove portions 57B and 56B in FIG. 3 are provided in the vibrating arms 35 and 34 is to reduce the rigidity of the vibrating arms 35 and 34, respectively.

As described above, the notches 100 and 100 shown in FIG. 3 are provided at one end and the other end of the base 51. If the notches 100, 100 are not provided in the base 51, the temperature characteristic curve may not be a quadratic curve but may be linear, and the presence of the notch 100 results in a temperature characteristic curve. It has been found that the linearity is suppressed.
The reason for this is that when the notch 100 is not provided, the stress is generated in the vibrating arms 35 and 34 in the portion where the base 51 is mounted on the electrode 31 using the conductive adhesive 43 as shown in FIG. It is thought that it affects the vibration mode (vibration characteristics).

  As shown in FIG. 2, through holes 37 a and 37 b that are continuous with the two laminated substrates constituting the package 36 are formed near the center of the bottom surface of the package 36. Is provided. Of the two through holes constituting the through hole 37, the outer through hole 37a, which is the second hole, has a larger inner diameter than the first hole 37b that opens inside the package. Yes. Thereby, the through-hole 37 is a stepped opening including a downward stepped portion 62 in FIG. It is preferable that a metal coating portion is provided on the surface of the stepped portion 62.

  Here, as the metal sealing material 38 filled in the through-hole 37, for example, a sealing material not containing lead is preferably selected. For example, silver brazing, Au / Sn alloy, Au / Ge alloy Selected from etc. Correspondingly, it is preferable to form nickel plating and gold plating on the tungsten metallization in the metal covering portion on the surface of the stepped portion 62.

A lid 39 is sealed at the opened upper end of the package 36 by being joined by a sealing material 33. The lid 39 is preferably sealed and fixed to the package 36, and then, as shown in FIG. 2, a laser beam L2 is radiated from the outside to a metal coating portion (described later) of the piezoelectric vibrating piece 32 to reduce the mass. In order to adjust the frequency, it is made of a material that transmits light, particularly, thin glass.
As a glass material suitable for the lid 39, for example, borosilicate glass is used, for example, as a thin glass manufactured by the downdraw method.

  Further, in FIG. 2, the recess 42 is provided by removing a part of the inside of the second substrate 64. Thereby, when an external impact is applied to the piezoelectric device 30, even if the tip of the piezoelectric vibrating piece 32 is displaced in the direction of the arrow D 1, the tip of the piezoelectric vibrating piece 32 collides with the inner bottom portion of the package 36. It is effectively prevented from being damaged.

Next, a cross-sectional shape example of the vibrating arms 34 and 35 and a structural example of the excitation electrodes 54 and 55 will be described with reference to FIGS. 3, 4, and 5. End faces of the vibrating arms 34 and 35 shown in FIG. 4 lie on a plane formed by the X direction (electric axis) and the Z direction (optical axis) in FIG.
First, the cross-sectional shape examples of the vibrating arms 34 and 35 illustrated in FIGS. 4 and 5 will be described in detail.
FIG. 4 shows an example of the end surfaces of the vibrating arms 34 and 35 along the line CC in FIG. 3 and the vibration directions in the M direction. FIG. 5 shows an example of the end face shape of the vibrating arms 34 and 35 shown in FIG. 4 and a laminated structure example of a partially enlarged excitation electrode. The vibrating arms 34 and 35 have the same cross-sectional shape.

  As shown in FIG. 4, the vibrating arm 34 has a front surface portion 200 and a back surface portion 210. Similarly, the vibrating arm 35 has a front surface portion 200 and a back surface portion 210. The surface portion 200 is a portion located on the upper side in FIG. 4 with respect to the central axis 300 of the vibrating arms 34 and 35. The back surface portion 210 is a portion located on the lower side of FIG. 4 with respect to the central axis 300 of the vibrating arms 34 and 35. The central axis 300 is a line parallel to the X direction (horizontal direction) and passes through the center of the cross-sectional shape of the vibrating arms 34 and 35.

The vibrating arms 34 and 35 each have a protrusion 350. The protrusion 350 is a portion formed to protrude in the + X direction across the front surface portion 200 and the back surface portion 210.
A first groove portion 57A and a second groove portion 57B are formed on the front surface portion 200 of the vibrating arm 34 and the back surface portion 210 of the vibrating arm 34. A first groove portion 56 </ b> A and a second groove portion 56 </ b> B are formed on the front surface portion 200 of the vibrating arm 35 and the back surface portion 210 of the vibrating arm 35. In order to distinguish the first groove portion and the second groove portion on the vibrating arm 34 side, the first groove portion is indicated by 57A and the second groove portion is indicated by 57B. In order to distinguish the first groove portion and the second groove portion on the vibrating arm 35 side, the first groove portion is indicated by 56A, and the second groove portion is indicated by 56B.

Since the first groove portions 57A and 56A shown in FIG. 5 have substantially the same shape and the second groove portions 57B and 56B have substantially the same shape, the shapes of the first groove portion 57A and the second groove portion 57B will be described as a representative.
As shown in FIG. 5, the first groove portion 57 </ b> A has inclined surfaces 501, 502, 503, and 504. Similarly, the second groove portion 57B has inclined surfaces 601, 602, 603, and 604. These inclined surfaces 501 to 504 form a bottomed first groove portion 57A. Similarly, these inclined surfaces 601 to 604 form a bottomed second groove portion 57B.

As shown in FIG. 4, the first groove portion 57A and the second groove portion 57B are formed on the front surface portion 200 and the back surface portion 210, respectively.
A center line CL1 illustrated in FIG. 4 is a line indicating the center of the first groove portion 57A on the surface portion 200 side of the vibrating arm 34. Similarly, the center line CL2 is a line indicating the center of the second groove portion 57B on the back surface side 210 of the vibrating arm 34. These center lines CL1 and CL2 are parallel to the Z direction.
A center line CL3 illustrated in FIG. 4 is a line indicating the center of the first groove portion 56A on the surface portion 200 side of the vibrating arm 35. The center line CL4 is a line indicating the center of the second groove portion 56B on the back surface portion 210 side of the vibrating arm 35.

As shown in FIG. 4, the center line CL <b> 1 and the center line CL <b> 2 are positioned in parallel so as to be shifted in opposite directions with respect to the X direction. Similarly, the center line CL3 and the center line CL4 are positioned in parallel so as to be shifted in opposite directions with respect to the X direction. That is, the first groove 57A and the second groove 57B are formed in parallel so as to be shifted in opposite directions with respect to the X direction. Also, the first groove portion 56A and the second groove portion 56B are formed in parallel so as to be shifted in opposite directions with respect to the X direction.
As described above, the center line CL1 and the center line CL2 are positioned in parallel so as to be shifted in opposite directions, and the following can be said.

As shown in FIG. 4, the width W <b> 1 of the protruding portion 360 on the surface portion 200 side is set smaller than the width W <b> 3 of the protruding portion 361. Further, the width W4 of the protruding portion 362 on the back surface portion 210 side is set smaller than the width W2 of the protruding portion 363.
Similarly, also in the vibrating arm 35, the width W1 of the protruding portion 460 on the surface portion 200 side is set smaller than the width W3 of the protruding portion 461. The width W4 of the protruding portion 462 on the back surface portion 210 side is set to be smaller than the width W2 of the protruding portion 463.
As described above, the first grooves 57A and 56A on the front surface 200 side and the second grooves 57B and 56B on the rear surface 210 side of the vibrating arms 34 and 35 are asymmetrical with respect to the central shaft 300.

Next, an example of forming the excitation electrodes 54 and 55 shown in FIGS. 3 to 5 will be described.
As shown in FIG. 3, the excitation electrodes 54 and 55 are driving electrodes, but the excitation electrodes 54 and 55 are provided in at least the first groove portions 56A and 57A and the second groove portions 56B and 57B as shown in FIG. It has been.
As described above, the excitation electrodes 54 and 55 shown in FIGS. 3 to 5 are electrically different from each other. As shown in FIG. 5, the excitation electrodes 54 and 55 are each a laminated structure of a base layer 75A and an electrode layer 75B. The underlayer 75A is, for example, a Cr layer. The electrode layer 75B is an Au layer. The underlayer 75A may be a Ni layer or a Ti film instead of the Cr layer. The electrode layer 75B is not limited to the Au layer but may be an Ag layer. The Cr layer is a film suitable as a base layer of the piezoelectric vibrating piece, and the temperature characteristics are improved by the influence of stress generated by the formation of the Cr layer.

The base layer 75A of the excitation electrodes 54 and 55 shown in FIG. 5 is formed directly on the surfaces of the vibrating arms 35 and 34. The electrode layer 75B is formed by being laminated on the base layer 75A. A gap 180 for preventing a short circuit is formed between the excitation electrode 54 and the other excitation electrode 55 of the vibrating arm 34 shown in FIG. Similarly, an interval 180 for preventing a short circuit is formed between the excitation electrode 55 of the vibrating arm 35 and the other excitation electrode 54.
By providing an oxide film such as SiO _{2 in} the vicinity of the short-circuit prevention interval 180, it is possible to reliably prevent the excitation electrodes 54 and 55 from being short-circuited. As shown in FIG. 4, in one vibrating arm 34, the excitation electrode 54 is formed on the first groove portion 57A and the second groove portion 57B side, and the excitation electrode 55 is formed as an electrode on the side surface portion side. Similarly, in the other vibrating arm 35, the excitation electrode 55 is formed on the first groove portion 56A and the second groove portion 56B side, and the excitation electrode 54 is formed as an electrode on the side surface portion side.

  Electric fields E1 and E2 are indicated by arrows on the pair of vibrating arms 34 and 35 shown in FIG. When a driving voltage is applied to the excitation electrodes 54 and 55, an electric field as exemplified by an arrow is generated in the vibrating arms 34 and 35. That is, when a predetermined AC voltage is applied to the electrodes, electric fields E1 and E2 are alternately generated between adjacent excitation electrodes 54 and 55, and the vibrating arms 34 and 35 repeatedly perform bending motions in opposite directions.

As described above, each of the vibrating arms 34 and 35 employs a structure in which the front surface portion 200 and the back surface portion 210 are provided with the first groove portions 57A and 56A and the second groove portions 57B and 56B that are shifted from each other in the center line. In other words, a size relationship is provided for the widths of the protruding portions 360 and 361, and a size portion is also provided for the widths of the protruding portions 362 and 363. Similarly, the protruding portion 460 and the protruding portion 461 are also provided with a magnitude relationship with respect to the width, and the protruding portion 462 and the protruding portion 463 are also provided with a size relationship with respect to the width.
By energizing the excitation electrodes 54 and 55 shown in FIG. 4, an electric field E1 and an electric field E2 as shown in FIG. As shown in FIG. 4, the magnitude of the electric field on the protruding portion 360 side is smaller than the magnitude of the electric field on the protruding portion 361. The electric field of the protruding portion 362 is smaller than the electric field on the protruding portion 363 side. The same applies to the vibrating arm 35.

By doing so, when the vibrating arms 34 and 35 bend and vibrate in the X direction (horizontal direction), in addition to the horizontal bending vibration, vibration of the component in the Z direction (vertical direction) is added. As a result, A vibration component in the M direction, which is an oblique direction, is generated.
This is because different electric fields are generated on the front surface 200 side and the back surface 210 side. As described above, when the magnitude of the electric field E1 and E2 varies depending on the portion, the mechanical balance between expansion and contraction of the vibrating arms 34 and 35, which are tuning fork arms, is lost, and bending vibration in the X direction is caused. On the other hand, a vibration component in the Z direction is added to generate a vibration component in the M direction.

As described above, the present inventor arranges the center lines of the first groove portion on the front surface side and the second groove portion on the back surface side in parallel so as to be shifted in opposite directions to each other. We found a phenomenon in which the second-order coefficient of N becomes small.
FIG. 6 shows an example of temperature characteristics (frequency).
FIG. 6 shows an embodiment of the present invention and an example of a conventional normal tuning fork type piezoelectric vibrating piece. The normal tuning fork type piezoelectric vibrating piece has a temperature characteristic curve 640 that is a convex quadratic function having an apex temperature.

The temperature characteristic curve 700 of the piezoelectric vibrating piece according to the embodiment of the present invention shown in FIG. 6 is not a bilateral function temperature characteristic curve of a symmetric type, and a substantially flat portion 750 is obtained. The temperature characteristic curve 700 of the form is not a quadratic function curve but a cubic function curve. The flat portion 750 of the temperature characteristic curve 700 according to the embodiment of the present invention is, for example, in the range of minus 20 degrees Celsius to plus 50 degrees Celsius.
By obtaining the temperature characteristic curve 700 of the embodiment of the present invention having such a flat portion 750, a highly accurate temperature characteristic curve with a small change in frequency deviation due to a temperature change can be obtained.

  As shown in FIG. 2, the base 51 of the piezoelectric vibrating piece is mounted with a conductive adhesive 43 such as, for example, an Ag paste of Si. The stress generated by this mounting also affects the vibration mode of the piezoelectric vibrating piece. Therefore, it seems to affect the temperature characteristics. When the temperature moves to the high temperature side or the low temperature side, the influence of the stress due to the conductive adhesive is large, and this seems to affect the temperature characteristic curve on the low temperature side. Even with the same Si-based conductive adhesive, there is a difference in the second order coefficient of the temperature characteristic curve.

  Also, as shown in FIG. 3, the base 51 is provided with, for example, notches 100, 100, so that the CI (crystal impedance) value changes. Since the notch 100 is provided in the base 51, the presence of this notch makes the temperature characteristic curve not a linear curve but a quadratic curve, and suppresses the temperature characteristic curve from becoming linear. I know that The reason for this is considered that when there is no notch, the stress of the mount affects the vibrating arm and affects the vibration mode.

Since the first and second groove portions are formed in each of the vibrating arms 34 and 35, the rigidity of the vibrating arms 34 and 35 is reduced to obtain a temperature characteristic curve 700 as shown in FIG. The groove depth G shown in FIG. 3 is formed to be 30% or more and less than 50% with respect to the thickness of the vibrating arm, so that the rigidity of the vibrating arm is reduced, and a temperature characteristic curve 700 as shown in FIG. Can be obtained. When the groove width E shown in FIG. 3 is 40% or more of the width W of the vibrating arm, the temperature characteristic curve 700 shown in FIG. 6 can be obtained by reducing the rigidity.
The frequency at which the piezoelectric vibrating piece 32 shown in FIG. 3 oscillates is approximately 30 KHz to 40 KHz. As a result, a temperature characteristic curve 700 shown in FIG. 6 is obtained.

In the so-called grooved piezoelectric vibrating piece 32 as in the embodiment of the present invention, the flat portion 750 can be obtained by reducing the secondary coefficient considerably in the temperature characteristic curve 700 as shown in FIG. As a result, a change in frequency deviation due to a change in temperature can be reduced, and a highly accurate piezoelectric vibrating piece and piezoelectric device can be obtained.
Further, in the piezoelectric vibrating piece of the present invention, the Au film in the groove forming part (an important part that determines the vibration mode and characteristics) is actually peeled off, and the SiO ₂ coating (insulator for preventing short circuit between electrodes) is formed. It has been given.

Next, FIG. 7 to FIG. 9 are process diagrams for explaining an example of the manufacturing method of the piezoelectric vibrating piece 32 of the present embodiment, and each process of FIG. 7 to FIG. 9 is a part corresponding to FIG. The regions corresponding to the cut surfaces of the vibrating arms 34 and 35 shown in the cut end view are shown in the order of steps.
7 to 9 (k) show the outer shape etching process, and FIG. 9 (l) shows an example of the excitation electrode obtained in the electrode forming process.

  In FIG. 7A, a substrate 71 made of a piezoelectric material having a size capable of separating plural or many piezoelectric vibrating reeds 32 is prepared. At this time, when the substrate 71 is a tuning-fork type piezoelectric vibrating piece 32 as the process proceeds, the substrate 71 is piezoelectric so that the X axis shown in FIG. 3 is the electric axis, the Y axis is the mechanical axis, and the Z axis is the optical axis. It will be cut from a material, for example a single crystal of quartz. Further, when cutting from a single crystal of quartz, in the above-described orthogonal coordinate system composed of the X-axis, Y-axis, and Z-axis, the XY plane composed of the X-axis and the Y-axis is about minus 5 degrees clockwise around the X-axis. Or it is tilted plus 5 degrees.

(Corrosion-resistant film formation process)
As shown in FIG. 7A, a corrosion-resistant film 72 is formed on the surface (front and back surfaces) of the substrate 71 by a technique such as sputtering or vapor deposition. As shown in the drawing, a corrosion-resistant film 72 is formed on both front and back surfaces of a substrate 71 made of quartz, and the corrosion-resistant film 72 is composed of, for example, a chromium layer as a base layer and a gold coating layer coated thereon. Is done.
In the following steps, since the same processing is performed on both the upper and lower surfaces of the substrate 71, only the upper surface will be described in order to avoid complexity.

(Outline patterning process)
Next, as shown in FIG. 7B, a resist 73 is applied to the entire surface of the corrosion-resistant film 72 on the front and back of the substrate 71 (resist application step). Then, a resist 73 is applied for patterning the outer shape. As the resist 73, for example, an ECA-based or PGMEA-based positive resist can be preferably used.

(Etching process)
Then, as shown in FIG. 7C, a mask (not shown) having a predetermined pattern width is arranged for patterning of the outer shape, and after exposure, the exposed resist 73 is removed to correspond to the removed resist portion. Then, the corrosion resistant film 72 is also removed in the order of Au and Cr.
Next, as shown in FIG. 7D, an outer portion is exposed from the outer shape of the piezoelectric vibrating piece 32, and a resist 74 is applied to the entire surface as shown in FIG. 7E.

Next, as shown in FIG. 7 (f), the resist 74 in the outer portion from the outer shape of the piezoelectric vibrating piece 32 and the groove portion of each vibrating arm is removed.
Then, as shown in FIG. 8G, for the substrate 71 exposed as an outer portion from the outer shape of the piezoelectric vibrating piece 32, for example, the outer shape of the piezoelectric vibrating piece is etched using a hydrofluoric acid solution as an etching solution (etching). Process). This etching process changes in 2 to 3 hours depending on the concentration, type and temperature of the hydrofluoric acid solution. In this embodiment, hydrofluoric acid and ammonium fluoride are used as an etchant, and the etching process is completed in about two and a half hours under the conditions of a volume ratio of 1: 1 and a temperature of 65 ° ± 1 ° (Celsius). To do.

(Half etching process)
Next, as shown in FIG. 8H, the corrosion resistant film 72 in the groove portion of the vibrating arm is removed.
As shown in FIG. 8I, the substrate 71 exposed by removing the corrosion-resistant film 72 is further half-etched using a hydrofluoric acid solution or the like.
In this embodiment, hydrofluoric acid and ammonium fluoride are used as an etchant, and the etching process takes about 30 to 60 minutes depending on the conditions of a volume ratio of 1: 1 and a temperature of 65 ° ± 1 ° (Celsius). Is completed.
Thus, the first groove portions 57A and 56A and the second groove portions 57B and 56B of the vibrating arms 34 and 35 are formed.

Next, as shown in FIG. 8J, the resist 74 is removed from the corrosion-resistant film 72, and the corrosion-resistant film 72 is also removed to obtain the state shown in FIG. This state is a state in which the electrode of the piezoelectric vibrating piece 32 of FIG. 3 is not formed.
Subsequently, in the electrode forming step shown in FIG. 9L, a metal film 75 for forming electrodes on the entire surface is formed by a technique such as vapor deposition or sputtering. The metal film 75 is the excitation electrodes 54 and 55, and is composed of a chromium layer as the underlying layer 75A, which is the same as the corrosion-resistant film, and an electrode layer (gold coating layer) 75B coated thereon.

After that, a resist coating process is performed in the electrode formation, and masking (not shown) for separating the region where the electrode is to be formed (see FIG. 3) and the region where the electrode is not formed is made, exposed, and unnecessary resist is removed. Then, the metal film 75 to be removed is exposed. Next, the exposed metal film is removed by wet etching using an etchant such as potassium iodide. Thereby, all the metal film 75 to be removed is removed by etching. Finally, all unnecessary resist is removed.
Thus, the piezoelectric vibrating piece 32 having the structure described with reference to FIGS. 3 and 4 is completed.

  The piezoelectric vibrating piece 32 completed as shown in FIG. 3 is joined to the inside of the package 36 using a conductive adhesive 43 as shown in FIGS. Thereafter, a lid 39 is joined to the package 36 using a brazing material (for example, low melting point glass). Furthermore, the package 36 is heated in a vacuum, the inside of the package 36 is degassed through the through hole 37, and the through hole 37 is vacuum sealed with a sealing material 38, thereby completing the piezoelectric device 30. it can.

The piezoelectric device 30 of the present embodiment has the configuration shown in FIGS. 1 and 2, and an example of a method for manufacturing the piezoelectric device 30 will be described mainly with reference to FIG.
FIG. 10 is a flowchart illustrating an example of a method for manufacturing the piezoelectric device 30.
(Formation process)
First, the package 36 of FIGS. 1 and 2 is formed and prepared (step ST11), and separately from this, the lid 39 is formed (step ST211).

  Next, in step ST111, which is the first stage of the formation process for forming the piezoelectric vibrating piece, the outer shape of the piezoelectric vibrating piece is formed by drilling or etching a through hole in a quartz wafer, for example. Then, the crystal wafer is cut into a rectangle according to a predetermined orientation to obtain the piezoelectric vibrating piece 32 shown in FIG. The piezoelectric vibrating piece 32 is formed by etching the outer shape by the manufacturing process shown in FIGS. 7, 8, and 9 (k).

  Next, in step ST112 which is the second stage of the formation process, the excitation electrodes 54 and 55 and the extraction electrodes 52 and 53 described above are formed on the piezoelectric vibrating piece 32 shown in FIG. The excitation electrodes 54 and 55 and the extraction electrode portions 52 and 53 are formed by laminating a base layer (base metal layer) made of, for example, chromium, and an electrode layer of silver (Ag) or gold (Au) layer, and are sequentially formed by sputtering. A film is formed by a photo process using a mask.

Next, in step ST113 of FIG. 10, the drive voltage is applied to the piezoelectric vibrating piece 32, the frequency is measured, an electrode film is added, or a part thereof is trimmed with a laser beam or the like, thereby roughly adjusting the frequency. Do.
Next, in step ST12 of FIG. 10, the piezoelectric vibrating piece 32 is mounted in the prepared package 36.

(Sealing process)
Next, in step ST13 of FIG. 10, which is a sealing process, the lid 39 is sealed using the sealing material 33 on the package 36 of FIG. 2 in a vacuum or in an inert gas atmosphere such as nitrogen. Thus, the package 36 is hermetically sealed.
Next, in step ST14 of FIG. 10, as described with reference to FIG. 2, frequency adjustment is performed to complete the piezoelectric device 30 that is a piezoelectric vibrator (step ST15).

FIG. 11 is a diagram showing a schematic configuration of a digital mobile phone device as an example of an electronic apparatus using the piezoelectric device according to the above-described embodiment of the present invention.
In the figure, a microphone 308 for receiving the voice of the sender and a speaker 309 for outputting the received content as a voice output are provided, and further, an integrated circuit or the like as a control unit connected to the modulation and demodulation unit of the transmission / reception signal. A controller (CPU) 301 is provided.

  The controller 301 includes an LCD (liquid crystal display device) as an image display unit in addition to modulation and demodulation of transmission / reception signals, an information input / output unit 302 including operation keys for information input, a RAM (random access memory), Information storage means (memory) 303 composed of ROM (read only memory) or the like is controlled. Therefore, the piezoelectric device 30 is attached to the controller 301, and the output frequency is used as a clock signal suitable for the control content by a predetermined frequency dividing circuit (not shown) built in the controller 301. Has been. The piezoelectric device 30 attached to the controller 301 may not be a single piezoelectric device 30 but may be an oscillator that combines the piezoelectric device 30 and a predetermined frequency dividing circuit.

  The above-described piezoelectric device 30 according to the embodiment of the present invention and other modified piezoelectric devices can be used in an electronic apparatus such as the digital cellular phone device 300 including the control unit. In this case, since there is a flat portion in the temperature characteristic curve, the frequency deviation change due to the temperature change is reduced, and the operation accuracy of the electronic device is improved.

FIG. 12 illustrates another embodiment of the present invention. FIG. 12 shows another example of a cross-sectional structure taken along the line CC of the vibrating arm of the piezoelectric vibrating piece in FIG.
In FIG. 12, the shapes of the first groove portions 57A and 56A on the front surface portion 200 and the back surface portion 210 side and the second groove portions 57B and 56B on the back surface portion 210 side are substantially rectangular. Since the embodiment of FIG. 12 is almost the same as the embodiment of FIG. 4 in other points, the description will be used.

FIG. 13 shows yet another embodiment of the present invention.
The embodiment of FIG. 13 is characterized in that the thickness of the excitation electrode is set to be different between the front surface portion 200 side and the back surface portion 210 side in both cases of the vibrating arms 34 and 35.
In the example of FIG. 13, the center lines of the first groove portion 57A and the second groove portion 57B coincide. Similarly, the center lines of the first groove portion 56A and the second groove portion 56B also coincide with each other.
Regarding the central axis 300 of the vibrating arms 34 and 35, the thickness R of the excitation electrodes 54 and 55 on the front surface portion 200 side is set larger than the thickness R1 of the excitation electrodes 54 and 55 on the rear surface portion 210 side.

The excitation electrodes 54 and 55 on the surface portion 200 side are a laminated structure of a base layer 75A and an electrode layer 75B. The thickness V of the base layer 75A on the front surface portion 200 side is set to be larger than the thickness V1 of the base layer 75A on the back surface portion 210 side. For example, Cr, Ni, or Ti can be used as the base layer 75A. As the electrode layer 75B, Au or Ag can be used.
In this way, when the thickness V of the base layer 75A on the front surface portion 200 side is set larger than the thickness V1 of the base layer 75A on the back surface portion 210 side, the following occurs.

By energizing the excitation electrodes 54 and 55, when the vibrating arms 34 and 35 vibrate in the horizontal direction, which is the X direction, in addition to the horizontal vibration, vibration of the vertical component in the Z direction is applied. As a result, vibration in the M direction, which is an oblique direction, occurs. This is because there is a difference in the magnitude of stress depending on the thickness of the underlayer on the front surface 200 side and the back surface 210 side with respect to the X direction, which is the horizontal direction.
In order to achieve horizontal bending vibration, the mechanical balance between the expansion and contraction of the vibrating arms 34 and 35 generated by this electric field needs to be taken on the front surface portion 200 side and the back surface portion 210 side. When the magnitude of the stress on the side and the back surface 210 side is different, the mechanical balance between expansion and contraction of the vibrating arms 34 and 35 is lost, and a vibration component in the Z direction is added to the bending vibration in the X direction. The vibration in the M direction occurs.

In this way, the thickness of the electrode on the front surface portion 200 side and the thickness of the electrode on the back surface portion 210 side are changed to make the thickness asymmetric with respect to the central axis 300, as shown in FIG. A temperature characteristic curve having a flat portion can be obtained, and the temperature characteristic of the piezoelectric vibrating piece is improved.
It should be noted that, of course, a combination of changing the thickness of the electrode as shown in FIG. 13 may be combined with the vibrating arms 34 and 35 having a cross-sectional structure as shown in FIG. 4 or FIG.

Each configuration of each embodiment of the present invention can be combined as appropriate, or a part thereof can be omitted and combined with other configurations not shown.
Further, the present invention is not limited to the name of a crystal resonator, a crystal oscillator, a gyroscope, an angle sensor, etc., as long as the piezoelectric resonator element is accommodated in a package or a box-shaped lid. It can be applied to a piezoelectric device using

Further, in the above-described embodiment, a box-shaped package using ceramics is used. However, the present invention is not limited to such a configuration, and the piezoelectric vibration is equivalent to a package such as a metal cylindrical case. The present invention can be applied to any package or case with a case as long as it accommodates a piece.
The present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the claims.

The schematic plan view which shows embodiment of the piezoelectric device of this invention. BB schematic sectional drawing of FIG. FIG. 2 is a schematic perspective view of a piezoelectric vibrating piece housed in the package of the piezoelectric device of FIG. 1. The CC sectional view taken on the line of FIG. The figure which shows the electrode structure in a CC cut end surface shown in FIG. 4, a 1st groove part, and a 2nd groove part. The figure which shows the temperature characteristic curve of embodiment of this invention and a prior art example. FIG. 2 is a schematic process diagram sequentially illustrating a manufacturing process of a piezoelectric vibrating piece housed in the piezoelectric device of FIG. 1. FIG. 2 is a schematic process diagram sequentially illustrating a manufacturing process of a piezoelectric vibrating piece housed in the piezoelectric device of FIG. 1. FIG. 2 is a schematic process diagram sequentially illustrating a manufacturing process of a piezoelectric vibrating piece housed in the piezoelectric device of FIG. 1. The figure which shows the example of the manufacturing method of a piezoelectric device. The figure which shows the example of a digital type mobile telephone apparatus. The figure which shows another embodiment of the vibrating arm of this invention. The figure which shows another embodiment of the vibrating arm of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 30 ... Piezoelectric device, 32 ... Piezoelectric vibration piece, 34, 35 ... Vibrating arm, 51 ... Base part, 54, 55 ... Excitation electrode, 56A, 57A ... 1st groove part, 56B 57B ... second groove portion, 75A ... underlayer, 75B ... electrode layer, 100 ... cut portion, 200 ... front surface portion, 210 ... back surface portion, 640 ... conventional Temperature characteristic curve, 700 ... Temperature characteristic curve of the embodiment of the present invention, 750 ... Flat part of the temperature characteristic curve

Claims (9)

The base,
A plurality of vibrating arms extending in parallel from the base,
The base is provided with a notch, a first groove is formed on the surface of the vibrating arm, and a second groove is formed on the back of the vibrating arm,
At least the groove is provided with a driving electrode,
The shape on the front surface side of the vibrating arm and the shape on the back surface side of the vibrating arm are asymmetric so as to break the mechanical balance between expansion and contraction when the vibrating arm vibrates when the electrode is energized. A piezoelectric vibrating piece characterized in that it is formed as follows.   2. The piezoelectric vibration according to claim 1, wherein a center line of the first groove portion and a center line of the second groove portion are shifted in opposite directions in a cross section intersecting with a longitudinal direction of the vibrating arm. Piece.   The electrode has a base layer and an electrode layer formed on the base layer, and the thickness of the base layer of the electrode on the surface portion side of the vibrating arm is the electrode on the back surface side of the vibrating arm. The piezoelectric vibrating piece according to claim 1, wherein the thickness is different from the thickness of the base layer.   The piezoelectric vibrating piece according to claim 3, wherein the base layer is Cr, and the electrode layer is Au. A piezoelectric device containing a piezoelectric vibrating piece in a package,
The piezoelectric vibrating piece is
The base,
A plurality of vibrating arms extending in parallel from the base,
A cut portion is provided in the base, a first groove is formed on the vibrating arm, and a second groove is formed on the back surface of the vibrating arm,
At least the groove is provided with a driving electrode,
The shape on the front surface side of the vibrating arm and the shape on the back surface side of the vibrating arm are asymmetric so as to break the mechanical balance between expansion and contraction when the vibrating arm vibrates when the electrode is energized. A piezoelectric device characterized in that it is formed. A base portion and a plurality of vibrating arms extending in parallel from the base portion, the base portion is provided with a cut portion, and a first groove portion is formed on a surface portion of the vibrating arm, A method of manufacturing a piezoelectric vibrating piece, wherein a second groove is formed on the back surface, and at least the groove is provided with a piezoelectric vibrating piece having a driving electrode,
In the outer shape etching step of forming an outer shape by etching a substrate made of a piezoelectric material, the shape of the vibrating arm on the surface portion side and the shape of the vibrating arm on the back surface portion side are energized to the electrode to generate the vibration. A method of manufacturing a piezoelectric vibrating piece, wherein the arm is formed asymmetrically so as to break a mechanical balance between expansion and contraction when the arm vibrates. A base portion and a plurality of vibrating arms extending in parallel from the base portion, the base portion is provided with a cut portion, and a first groove portion is formed on a surface portion of the vibrating arm, A method of manufacturing a piezoelectric device in which a second groove portion is formed on a back surface portion, and at least the groove portion includes a piezoelectric vibrating piece having a driving electrode in a package,
In the outer shape etching step of forming an outer shape by etching a substrate made of a piezoelectric material, the shape of the vibrating arm on the surface portion side and the shape of the vibrating arm on the back surface portion side are energized to the electrode to generate the vibration. A method for manufacturing a piezoelectric device, wherein the piezoelectric device is formed asymmetrically so as to break a mechanical balance between expansion and contraction when the arm vibrates. A cellular phone device configured to obtain a clock signal for control by a piezoelectric device that houses a piezoelectric vibrating piece in a package,
The piezoelectric vibrating piece is
The base,
A plurality of vibrating arms extending in parallel from the base,
The base is provided with a notch, a first groove is formed on the surface of the vibrating arm, and a second groove is formed on the back of the vibrating arm,
At least the groove is provided with a driving electrode,
The shape on the front surface side of the vibrating arm and the shape on the back surface side of the vibrating arm are asymmetric so as to break the mechanical balance between expansion and contraction when the vibrating arm vibrates when the electrode is energized. A cellular phone device characterized by being formed in the above. An electronic device in which a clock signal for control is obtained by a piezoelectric device containing a piezoelectric vibrating piece in a package,
The piezoelectric vibrating piece is
The base,
A plurality of vibrating arms extending in parallel from the base,
The base is provided with a notch, a first groove is formed on the surface of the vibrating arm, and a second groove is formed on the back of the vibrating arm,
At least the groove is provided with a driving electrode,
The shape on the front surface side of the vibrating arm and the shape on the back surface side of the vibrating arm are asymmetric so as to break the mechanical balance between expansion and contraction when the vibrating arm vibrates when the electrode is energized. An electronic device characterized in that it is formed.

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