JP2011223228A - Vibration chip, vibrator and oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration chip configured to avoid the short-cut between electrodes at the flank of a fork section without relying on a different shape part, a vibrator with the vibration chip and an oscillator with the vibration chip.SOLUTION: A crystal vibration chip 1 has a Z plate as a substrate, that is cut out of a crystal gemstone in specific angles to the X-axis, Y-axis and Z-axis, crossing one another as the crystallographic axis of a crystal, and the crystal vibration chip's external shape being formed using wet etching. It comprises a substrate 11, and a pair of vibration arms 12 and 13 extended along the Y-axis from the substrate 11. Excitation electrodes 20 and 21 are formed to the side surfaces 12a, 13a of the pair of vibration arms 12, 13, which sandwiches a fork section 19, connecting the root portion of the pair of vibration arms 12 and 13, and a protrusion 19b is formed on a side surface 19a which points to the plus side of the X-axis of the fork section 19. The protrusion 19b features an acute angle part 19c.

Description

  The present invention relates to a resonator element, a vibrator including the resonator element, and an oscillator including the resonator element.

  In Patent Document 1, in a tuning fork type crystal resonator (hereinafter referred to as a tuning fork type crystal vibrating piece), two arms of the tuning fork (hereinafter referred to as a vibrating arm) have an interval of a width D, and the tuning fork type crystal vibration is described. A tuning-fork type crystal vibrating piece having a distance H between the lowest part of the arc of the surface (main surface) of the crotch part and the apex of the crotch part and having a D / H of 6 to 14 is disclosed. .

Japanese Patent Laid-Open No. 5-308238 (FIG. 1)

Etching anisotropy whose etching rate varies depending on the direction with respect to the crystal axis of the crystal, such as the tuning-fork type crystal vibrating piece of Patent Document 1, is formed in a vibrating piece formed by wet etching (hereinafter, also simply referred to as etching). Thus, a fin-like deformed portion (etching residue) having an inclined surface may be formed on the side surface of the crotch portion connecting the plurality of vibrating arms (see FIG. 1 of Patent Document 1).
Due to the deformed portion of the resonator element, for example, stress concentration occurs in the crotch portion, and the vibrating arm may be damaged or the vibration characteristics may be deteriorated during high driving (a state where applied power is large).

It has been found that if the gap between the vibrating arms is widened (if the crotch portion is widened), this deformed portion is less likely to occur due to a change in the progress of etching.
However, the resonator element is in a situation where the interval between the vibrating arms cannot be easily widened because the deformed portion is used when forming the electrode.
Specifically, in the resonator element, unnecessary electrode material formed on the side surface of the crotch portion is easily removed by exposing the electrode patterning resist formed on the inclined surface of the deformed portion. It has become. Thereby, the short circuit between the electrodes on the side surface of the crotch portion is avoided in the resonator element.

  Therefore, the resonator element has a problem of realizing a configuration that can avoid a short circuit between electrodes on the side surface of the crotch portion without depending on the deformed portion.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  [Application Example 1] The resonator element according to this application example is based on a Z plate cut out at a predetermined angle with respect to the X axis, the Y axis, and the Z axis, which are orthogonal to each other, as crystal axes of quartz, and has an outer shape. Is a vibrating piece formed by wet etching, comprising a base portion and a plurality of vibrating arms extending from the base portion along the Y axis, and a crotch portion connecting the base portions of the plurality of vibrating arms. Electrodes are formed on the side surfaces of the plurality of vibrating arms, and a protrusion is formed on the side surface of the crotch portion facing the positive side of the X axis. The protrusion has an acute angle portion. It is characterized by that.

According to this, the resonator element has electrodes formed on the side surfaces of the plurality of vibrating arms across the crotch portion that connects the root portions of the plurality of vibrating arms, and on the side surface of the crotch portion facing the positive side of the X axis. A protrusion is formed, and the protrusion has an acute angle portion.
For this reason, when the electrode is formed on the side surface of the vibrating arm, it is difficult for the vibrating piece to adhere to the electrode material due to the acute angle portion of the protruding portion.
As a result, the vibration piece can avoid the short circuit between the electrodes on the side surface of the crotch portion by the protrusion portion without depending on the deformed portion as in the related art.

  Application Example 2 In the resonator element according to the application example described above, it is preferable that the ridge line of the acute angle portion extends so as to connect one main surface side and the other main surface side of the crotch portion.

  According to this, since the oscillating piece extends so that the ridge line of the acute angle portion connects one main surface side and the other main surface side of the crotch portion, electrode formation on the protrusion is further inhibited, A short circuit between the electrodes on the side surface of the crotch can be more reliably avoided by the protrusion.

  Application Example 3 In the resonator element according to the application example described above, it is preferable that a weight portion having a width wider than that of the arm portion of the vibrating arm is provided at a tip portion of the vibrating arm.

According to this, since the vibrating piece is provided with a weight portion having a width wider than the arm portion of the vibrating arm (a main body portion of the vibrating arm) at the tip portion of the vibrating arm, the Q due to an increase in the inertial mass of the weight portion. Due to the effect of improving the value, the vibrating arm can be shortened while maintaining the Q value.
As a result, the resonator element can be reduced in size while maintaining the Q value.

  Application Example 4 In the resonator element according to the application example described above, it is preferable that the tuning fork includes the plurality of vibrating arms and the base portion.

  According to this, since the vibrating reed includes a plurality of vibrating arms and a base, and constitutes a tuning fork, a tuning fork-type piezoelectric vibrating reed that can avoid a short circuit between electrodes on the side surface of the crotch by a protrusion is provided. it can.

  Application Example 5 A vibrator according to this application example includes the resonator element according to any one of Application Examples 1 to 4, and a package that accommodates the resonator element. .

  According to this, since the vibrator includes the resonator element according to any one of the application examples 1 to 4, the effect described in any one of the application examples 1 to 4 can be obtained. It is possible to provide a vibrator that performs.

  Application Example 6 An oscillator according to this application example includes a resonator element according to any one of Application Examples 1 to 4, a circuit element including an oscillation circuit that oscillates the resonator element, the resonator element, And a package for housing the circuit element.

  According to this, since the oscillator includes the resonator element according to any one of the application examples 1 to 4, the effect described in any one of the application examples 1 to 4 is achieved. An oscillator can be provided.

2A and 2B are schematic diagrams illustrating a schematic configuration of a resonator element according to the first embodiment, in which FIG. 3A is a plan view and FIG. The principal part expansion perspective view of Fig.1 (a). It is a schematic diagram which shows schematic structure of the vibrator | oscillator of 2nd Embodiment, (a) is a top view, (b) is sectional drawing of (a). It is a schematic diagram which shows schematic structure of the oscillator of 3rd Embodiment, (a) is a top view, (b) is sectional drawing of (a).

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic diagram illustrating a schematic configuration of the resonator element according to the first embodiment. FIG. 1A is a plan view, and FIG. 1B is a cross-sectional view taken along line AA in FIG. It is sectional drawing. FIG. 2 is an enlarged perspective view of a portion B in FIG. In the plan view of FIG. 1, the electrodes are simplified and partially omitted.

  As shown in FIG. 1, a quartz crystal vibrating piece 1 as a vibrating piece was cut out from a rough crystal or the like at a predetermined angle with respect to the X axis, Y axis, and Z axis orthogonal to each other as crystal axes of the crystal. A Z plate is used as a base material, and the outer shape is formed by wet etching using a photolithography technique.

Here, the Z plate means that the cut surface (main surface 10) is substantially orthogonal to the Z axis, and the main surface 10 orthogonal to the Z axis is from the Y axis when viewed from the plus side of the X axis. Those cut out in a state of rotating in the range of 0 degrees to several degrees counterclockwise or clockwise in the Z-axis direction are also included.
The crystal resonator element 1 is cut out from a single crystal of crystal so that the X axis is an electric axis, the Y axis is a mechanical axis, and the Z axis is an optical axis.
Note that the quartz crystal resonator element 1 can tolerate an error in the cut-out angle from the quartz crystal in a certain range (for example, a range of about 0 degree to 5 degrees) for each of the X axis, the Y axis, and the Z axis.

  The quartz crystal resonator element 1 includes a base portion 11, a pair of substantially parallel vibrating arms 12 and 13 extending from the base portion 11 along the Y axis, a pair of cutout portions 14 obtained by cutting the base portion 11 in the X axis direction, A pair of support portions 15 projecting from the base portion 11 in the X-axis direction, bent substantially at right angles to the vibrating arms 12 and 13 side, and extending in the Y-axis direction along the vibrating arms 12 and 13 are provided.

The pair of vibrating arms 12 and 13 includes an arm portion 16 extending from the base portion 11 in the Y-axis direction, a tip portion of the arm portion 16, a weight portion 17 that is wider than the arm portion 16 and extends in the Y-axis direction, The cross-sectional shape of the vibrating arms 12 and 13 formed along the extending direction (Y-axis direction) of the pair of vibrating arms 12 and 13 and cut along the direction in which the pair of vibrating arms 12 and 13 are arranged (X-axis direction) is as follows. And a groove portion 18 having a substantially H shape.
In addition, as shown in FIG.1 (b), the groove part 18 does not become a rectangular shape by cross-sectional shape by etching anisotropy.

The quartz crystal resonator element 1 includes a pair of vibrating arms 12 and 13, a pair of vibrating arms 12, a main surface 10 a, the other main surface 10 b, and a pair of crotch portions 19 that connect the root portions of the vibrating arms 12 and 13. Electrodes are formed on the side surfaces 12 a and 13 a of the vibrating arms 12 and 13.
In the quartz crystal resonator element 1, a projection 19 b is formed on a side surface 19 a of the crotch portion 19 facing the positive side of the X axis. And the projection part 19b has the acute angle part 19c.
The ridgeline of the acute angle portion 19c extends so as to connect the one main surface 10a side of the crotch portion 19 and the other main surface 10b side.
In addition, it is preferable that the base of the protrusion part 19b and the side surface 19a are connected with the curved surface in order to relieve stress concentration.

Note that the quartz crystal resonator element 1 has a desired shape due to the etching anisotropy of the crystal when the projection 19b is set on the side surface opposite to the side surface 19a of the crotch portion 19 (the side surface facing the negative side of the X axis). There is a possibility that the shape of this is not formed stably.
Thereby, the crystal vibrating piece 1 is formed on the side surface 19a in which the protrusion 19b faces the plus side of the X-axis of the crotch portion 19.

As shown in FIG. 1, the quartz crystal vibrating piece 1 is a tuning fork type quartz crystal vibrating piece as a tuning fork type vibrating piece by forming a tuning fork including a base 11 and a pair of vibrating arms 12 and 13. , And is fixed to an external member such as a package at a predetermined position of the support portion 15.
In the quartz crystal resonator element 1, the drive signal is applied from the outside to excitation electrodes 20 and 21 as electrodes to be described later formed on the pair of vibration arms 12 and 13, so that the pair of vibration arms 12 and 13 is formed. , Bending vibration (resonance) alternately in the direction of the arrow C and the direction of the arrow D at a predetermined frequency (for example, 32 kHz).

Here, the excitation electrodes 20 and 21 formed on the pair of vibrating arms 12 and 13 will be described in detail.
As shown in FIG. 1B, excitation electrodes 20 and excitation electrodes 21 having different polarities of applied potentials of drive signals applied from the outside are formed on the pair of vibrating arms 12 and 13.
Therefore, the excitation electrode 20 and the excitation electrode 21 are set to be spaced from each other so as not to be short-circuited.
Excitation electrodes 20 are formed in the groove portion 18 of the vibrating arm 12, and excitation electrodes 21 are formed on both side surfaces of the vibrating arm 12. The excitation electrodes 21 on both side surfaces of the vibrating arm 12 are connected to each other via connection electrodes 22 formed on the weight portion 17.

On the other hand, an excitation electrode 21 is formed in the groove portion 18 of the vibrating arm 13, and excitation electrodes 20 are formed on both side surfaces of the vibrating arm 13.
The excitation electrodes 20 on both side surfaces of the vibrating arm 13 are connected to each other via connection electrodes 22 formed on the weight portion 17.
The excitation electrodes 20 and 21 are drawn out to the support portion 15 via the base portion 11, and the drawn portions are mount electrodes 20a and 21a used when being fixed to an external member such as a package. The mount electrodes 20a and 21a are formed on both the one main surface 10a and the other main surface 10b.

As shown in FIG. 2, an excitation electrode 21 is formed on the side surface 12 a of the vibrating arm 12 across the crotch portion 19, and an excitation electrode 20 is formed on the side surface 13 a of the vibrating arm 13.
That is, excitation electrodes 20 and excitation electrodes 21 having different polarities of applied potentials are formed on the side surfaces 12a and 13a of the pair of vibrating arms 12 and 13 connected by the crotch portion 19 with the crotch portion 19 interposed therebetween. Yes.
In the crystal resonator element 1, if the excitation electrode 20 and the excitation electrode 21 formed on the side surfaces 12 a and 13 a of the vibrating arms 12 and 13 are not divided by the crotch portion 19, the excitation electrode 20 and the excitation electrode 21 are short-circuited. It will be.

Here, an outline of a method for forming the excitation electrodes 20 and 21 will be described.
For the excitation electrodes 20 and 21, an electrode material such as Ni, Cr, Au, Ag, Al, or Cu is formed on substantially the entire surface of the quartz crystal vibrating piece 1 by a method such as vapor deposition or sputtering. A resist is applied to cover and exposed to a desired electrode pattern shape using a photolithographic technique or the like, and then an unnecessary portion of the electrode material exposed is removed by etching to form a desired electrode pattern shape. The

At this time, since the projection 19b of the crotch portion 19 of the pair of vibrating arms 12 and 13 has an acute angle portion 19c, the electrode material adheres at the stage of deposition of the electrode material by vapor deposition or sputtering. It is difficult.
As a result, in the quartz crystal resonator element 1, even if the resist is not sufficiently exposed on the side surface 19 a of the crotch portion 19, the formation of the excitation electrodes 20 and 21 on the protrusion portion 19 b is inhibited.
In addition, the crystal vibrating reed 1 extends so that the ridge line 19d of the acute angle portion 19c connects the one main surface 10a side and the other main surface 10b side of the crotch portion 19 to the protrusion portion 19b. The formation of the excitation electrodes 20 and 21 is inhibited from the one main surface 10a side of the side surface 19a of the projection 19b to the other main surface 10b side.

As described above, in the crystal vibrating piece 1 of the first embodiment, the protrusion 19b is formed on the side surface 19a of the crotch portion 19 facing the positive side of the X axis, and the protrusion 19b has the acute angle portion 19c. ing.
Thereby, the crystal vibrating piece 1 is in a state in which the electrode material is difficult to adhere to the protrusion 19b by the acute angle portion 19c at the stage of film formation of the electrode material using vapor deposition, sputtering or the like. Formation of the excitation electrodes 20 and 21 to 19b is inhibited.
As a result, the crystal vibrating reed 1 can avoid the short circuit between the excitation electrodes 20 and 21 on the side surface 19a of the crotch portion 19 by the projection portion 19b without depending on the conventional deformed portion.

In addition, the crystal vibrating reed 1 extends so that the ridge line 19d of the acute angle portion 19c connects the one main surface 10a side and the other main surface 10b side of the crotch portion 19 to the protrusion portion 19b. The formation of the excitation electrodes 20 and 21 is inhibited from the one main surface 10a side of the side surface 19a of the projection 19b to the other main surface 10b side.
As a result, the quartz crystal resonator element 1 can more reliably avoid the short circuit between the excitation electrodes 20 and 21 on the side surface 19a of the crotch portion 19 by the protruding portion 19b.

Further, since the quartz crystal resonator element 1 is provided with the weight portion 17 wider than the arm portion 16 at the tip portions of the vibrating arms 12 and 13, it is possible to improve the Q value by increasing the inertial mass of the weight portion 17. The vibrating arms 12 and 13 can be shortened while maintaining the Q value.
As a result, the crystal resonator element 1 can be reduced in size while maintaining the Q value.

  In addition, since the quartz crystal resonator element 1 includes a pair of vibrating arms 12 and 13 and a base portion 11 to form a tuning fork, a short circuit between the excitation electrodes 20 and 21 on the side surface 19a of the crotch portion 19 is prevented from occurring in the protruding portion 19b. Therefore, a tuning-fork type crystal vibrating piece that can be avoided can be provided.

In the above-described embodiment, the number of the vibrating arms 12 and 13 is a pair (two). However, the number is not limited to this and may be three or more.
Moreover, the notch part 14, the support part 15, the weight part 17, and the groove part 18 are not necessary.
The direction of the bending vibration of the vibrating arms 12 and 13 may be the thickness direction (Z-axis direction) of the vibrating arms 12 and 13.

(Second Embodiment)
Next, as a second embodiment, a vibrator provided with the crystal vibrating piece described above will be described.
FIG. 3 is a schematic diagram illustrating a schematic configuration of the vibrator according to the second embodiment. FIG. 3A is a plan view, and FIG. 3B is a EE line in FIG. It is sectional drawing. In addition, in order to avoid complexity, the electrode of the crystal vibrating piece is omitted.

As shown in FIG. 3, a crystal resonator 5 as a resonator includes the crystal resonator element 1 of the first embodiment and a package 80 that houses the crystal resonator element 1.
The package 80 includes a package base 81, a seam ring 82, a lid 85, and the like.
The package base 81 is formed with a recess so that the crystal resonator element 1 can be accommodated, and a connection pad 88 connected to mount electrodes 20a and 21a (not shown) of the crystal resonator element 1 is provided in the recess. Yes.
The connection pad 88 is connected to the wiring in the package base 81 and is configured to be electrically connected to the external connection terminal 83 provided on the outer periphery of the package base 81.

A seam ring 82 is provided around the recess of the package base 81. Further, a through hole 86 is provided at the bottom of the package base 81.
The quartz crystal resonator element 1 is bonded and fixed to the connection pad 88 of the package base 81 via a conductive adhesive 84. In the package 80, a lid body 85 and a seam ring 82 that cover the concave portion of the package base 81 are seam-welded.
A through hole 86 of the package base 81 is filled with a sealing material 87 made of a metal material or the like. The sealing material 87 is solidified after being melted in a reduced pressure atmosphere, and the through hole 86 is hermetically sealed so that the inside of the package base 81 can be kept in a reduced pressure state.
The crystal resonator 5 is oscillated (resonated) at a predetermined frequency (for example, 32 kHz) when the crystal resonator element 1 is excited by an external drive signal via the external connection terminal 83.

  As described above, since the crystal resonator 5 includes the crystal resonator element 1, it is possible to provide a crystal resonator that exhibits the same effect as that of the first embodiment.

(Third embodiment)
Next, as a third embodiment, an oscillator including the quartz crystal resonator element described above will be described.
4A and 4B are schematic views showing a schematic configuration of the oscillator according to the third embodiment. FIG. 4A is a plan view, and FIG. 4B is a cross-sectional view taken along line FF in FIG. It is. In addition, in order to avoid complexity, the electrodes of the crystal vibrating piece are omitted.

The crystal oscillator 6 as an oscillator has a configuration in which a circuit element is further provided in the configuration of the crystal resonator 5. In addition, about the common part with the crystal oscillator 5, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.
As shown in FIG. 4, the crystal oscillator 6 includes the crystal resonator element 1 according to the first embodiment, an IC chip 91 as a circuit element having an oscillation circuit that oscillates the crystal oscillator piece 1, the crystal oscillator piece 1, and the IC. And a package 80 for accommodating the chip 91.
The IC chip 91 is fixed to the bottom of the package base 81 and is connected to other wiring by a metal wire 92 such as Au or Al.
In the crystal oscillator 6, the crystal resonator element 1 is excited by a drive signal from the oscillation circuit of the IC chip 91, and oscillates (resonates) at a predetermined frequency (for example, 32 kHz).

  As described above, since the crystal oscillator 6 includes the crystal resonator element 1, it is possible to provide a crystal oscillator that exhibits the same effects as those of the first embodiment.

  DESCRIPTION OF SYMBOLS 1 ... Crystal resonator element as a resonator element, 5 ... Crystal oscillator as a vibrator, 6 ... Crystal oscillator as an oscillator, 10 ... Main surface (cut-out surface), 10a ... One main surface, 10b ... Other main surface 11 ... Base, 12 ... Vibration arm, 12a ... Side, 13 ... Vibration arm, 13a ... Side, 14 ... Notch, 15 ... Support, 16 ... Arm, 17 ... Weight, 18 ... Groove, 19 ... Crotch part, 19a ... side face, 19b ... projection, 19c ... acute angle part, 19d ... ridgeline, 20, 21 ... excitation electrode as electrode, 20a, 21a ... mount electrode, 22 ... connection electrode, 80 ... package, 81 ... package Base, 82 ... Seam ring, 83 ... External connection terminal, 84 ... Conductive adhesive, 85 ... Cover, 86 ... Through hole, 87 ... Sealing material, 88 ... Connection pad, 91 ... IC chip as circuit element, 92 ... Metal wire.

Claims (6)

A vibrating plate whose outer shape is formed by wet etching using a Z plate cut at a predetermined angle with respect to the X axis, the Y axis, and the Z axis as crystal axes of quartz,
The base,
A plurality of resonating arms extending along the Y axis from the base,
Electrodes are formed on the side surfaces of the plurality of vibrating arms across the crotch connecting the base portions of the plurality of vibrating arms,
The crotch portion has a protrusion formed on a side surface facing the plus side of the X-axis, and the protrusion has an acute angle portion.   2. The resonator element according to claim 1, wherein a ridge line of the acute angle portion extends so as to connect one main surface side and the other main surface side of the crotch portion.   3. The resonator element according to claim 1, wherein a weight portion having a width wider than that of the arm portion of the vibrating arm is provided at a tip portion of the vibrating arm.   4. The vibrating piece according to claim 1, wherein the vibrating fork includes the plurality of vibrating arms and the base portion. 5. A vibrating piece according to any one of claims 1 to 4,
And a package for housing the resonator element. A vibrating piece according to any one of claims 1 to 4,
A circuit element having an oscillation circuit for oscillating the resonator element;
An oscillator comprising: the resonator element and a package that accommodates the circuit element.

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