JP2016178590A - Vibration piece, method for manufacturing vibration piece, vibrator, oscillator, electronic apparatus, and mobile body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration piece excellent in shock resistance, a method for manufacturing the vibration piece, and a vibrator, an oscillator, an electronic apparatus, and a mobile body including the vibration piece.SOLUTION: A vibration piece 100 of the present invention includes a base part 10, a pair of vibration arms 12, 13 juxtaposed and extending from the base part 10, and a groove part 42 formed on surfaces of the vibration arms 12, 13. The groove 42 is formed in such a manner that, in a cross section along a direction intersecting the extending direction, a width between side faces 46 opposing to each other on a bottom face 44 side is larger than a width in an aperture of the groove part 42, and that a curved shape is formed between the side face 46 and the bottom face 44.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a resonator element, a method for manufacturing the resonator element, a vibrator, an oscillator, an electronic device, and a moving body.

Electronic devices such as vibrators and oscillators are used in small information devices such as HDDs (hard disk drives), mobile computers, and IC cards, and mobile communication devices such as mobile phones, car phones, and paging systems. Widely used.
Conventionally, as a resonator element included in a vibrator or an oscillator, a base portion and a pair of vibrating arms extending in parallel so as to be parallel to each other from the base portion are provided. A vibrating piece having electrodes formed on each of the surfaces was used.
In recent years, along with downsizing of mounted devices, vibrators and oscillators have also been downsized. For this reason, a method is known in which a groove is provided on the surface of the vibrating arm to suppress an increase in impedance associated with downsizing. For example, in Patent Document 1, the groove portion is formed so as to gradually become wider in the short direction of the vibrating arm portion from the opening side toward the bottom wall surface side, and the impedance is lowered by increasing the electric field efficiency. A piezoelectric vibrating piece is disclosed.

JP 2013-207332 A

  However, in the resonator element described in Patent Document 1, since the corner formed by the side surface and the bottom wall surface of the groove is processed into an acute angle, stress is concentrated on the corner when an impact is applied, There was a risk that the vibrating arm would be damaged.

  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 A vibrating piece according to this application example includes a base, a pair of vibrating arms extending side by side from the base, and a groove formed on the surface of the vibrating arm. In a cross section in a direction intersecting with the extending direction, the width of the groove portion is formed so as to expand from the opening portion toward the bottom surface portion side, and a curved shape is formed between the side surface portion and the bottom surface portion. It is formed.

  According to this application example, since the width of the groove formed in the vibrating arm is formed so as to expand from the opening toward the bottom surface, the distance between the side surface of the vibrating arm and the side surface of the groove is reduced, and the electric field is reduced. Efficiency can be improved and a vibration piece with low impedance can be obtained. In addition, since a curved shape is formed between the side surface and the bottom surface, stress does not concentrate between the side surface and the bottom surface even if an impact is applied, reducing the risk of damage to the vibrating arm It is possible to obtain a resonator element having excellent impact resistance.

  [Application Example 2] A method for manufacturing a resonator element according to this application example is a method for manufacturing a resonator element in which the resonator element according to the above application example is formed from a wafer, and a groove forming process for forming a groove in the wafer. The groove forming step includes: a mask forming step of forming a metal mask on the wafer; and a dry etching step of continuously performing dry etching while forming a protective film on a side surface of the groove with a dry etching apparatus. It is characterized by having.

  According to this application example, in the groove forming process for forming the groove on the wafer, the etching gas pressure of the dry etching apparatus is increased to adjust the plasma mean free path to be shorter, and a protective film is formed on the side surface of the groove. However, by continuously performing dry etching, the width of the groove can be expanded from the opening toward the bottom surface, and a curved shape can be formed between the side surface and the bottom surface. Therefore, the distance between the side surface portion of the groove portion and the side surface of the vibrating arm can be narrowed, and the electric field efficiency can be increased and the impedance can be lowered. In addition, the curved shape between the side and bottom faces makes it difficult for stress to concentrate when an impact is applied, reducing the risk of damage to the vibrating arm, and vibration with excellent shock resistance. There is an effect that a piece can be manufactured.

  Application Example 3 A vibrator according to this application example includes the resonator element according to the application example described above and a package that accommodates the resonator element.

  According to this application example, a vibrator having low impedance and excellent shock resistance characteristics is accommodated in the package, whereby a vibrator having stable vibration characteristics and excellent shock resistance characteristics can be obtained.

  Application Example 4 An oscillator according to this application example includes the resonator element according to the application example, an electronic component including a circuit that drives the resonator element, and a package that accommodates the resonator element and the electronic component. It is characterized by having.

  According to this application example, an oscillator having stable oscillation characteristics and excellent shock resistance characteristics can be obtained by electrically connecting a resonator element having low impedance and excellent shock resistance characteristics to the oscillation circuit. .

  Application Example 5 An electronic apparatus according to this application example includes the resonator element according to the application example.

  According to this application example, an electronic device having high reliability can be configured by using a resonator element having low impedance and excellent impact resistance.

  Application Example 6 A moving object according to this application example includes the resonator element according to the application example.

  According to this application example, it is possible to configure a moving body having high reliability by using a resonator element having low impedance and excellent impact resistance.

FIG. 3 is a schematic plan view showing the structure of the resonator element according to the first embodiment of the invention. The schematic sectional drawing in the AA in FIG. Process drawing which shows the manufacturing method of the vibration piece which concerns on 2nd Embodiment of this invention. The schematic sectional drawing in the AA in FIG. 1 explaining a groove part formation process. The schematic block diagram which shows the structure of a dry etching apparatus. The schematic plan view which shows the structure of the gyro element as a vibration piece which concerns on 3rd Embodiment of this invention. The schematic plan view explaining the operation principle of the gyro element as a vibration piece which concerns on 3rd Embodiment of this invention. The schematic plan view which shows the structure of the gyro element as a vibration piece which concerns on 4th Embodiment of this invention. It is the schematic which shows the structure of the vibrator | oscillator provided with the vibration piece which concerns on embodiment of this invention, (a) is a schematic plan view, (b) is a schematic sectional drawing in the BB line in (a). FIG. 3 is a schematic cross-sectional view illustrating a structure of an oscillator including a resonator element according to an embodiment of the invention. The perspective view which shows the structure of the mobile type (or notebook type) personal computer as an electronic device provided with the vibration piece which concerns on embodiment of this invention. The perspective view which shows the structure of a mobile telephone (PHS is also included) as an electronic device provided with the vibration piece which concerns on embodiment of this invention. The perspective view which shows the structure of the digital camera as an electronic device provided with the vibration piece which concerns on embodiment of this invention. The perspective view which shows roughly the motor vehicle as a moving body provided with the vibration piece which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the scale of each layer and each member is different from the actual scale so that each layer and each member can be recognized. In addition, in FIGS. 1 to 10 except for FIGS. 3 and 5, for convenience of explanation, the X axis, the Y axis, and the Z axis are illustrated as three axes orthogonal to each other, and the tip side of the illustrated arrow is indicated. The “+ side” and the base end side are “− side”. In the following description, a direction parallel to the X axis is referred to as an “X axis direction”, a direction parallel to the Y axis is referred to as a “Y axis direction”, and a direction parallel to the Z axis is referred to as a “Z axis direction”. . Furthermore, for convenience of explanation, the surface in the Z-axis direction is a main surface in a plan view when viewed from the Z-axis direction, and the surface in the X-axis direction is a side surface in a plan view when viewed from the X-axis direction. explain.

<First Embodiment>
(Vibration piece)
First, a vibrating piece 100 having a tuning fork type structure will be described as an example of the vibrating piece according to the first embodiment of the present invention with reference to FIGS. 1 and 2.
FIG. 1 is a schematic plan view showing the structure of the resonator element according to the first embodiment of the invention. FIG. 2 is a schematic cross-sectional view taken along line AA in FIG. The vibrating element 100 is provided with a drive signal electrode, a drive signal wiring, a drive signal terminal, a drive ground electrode, a drive ground wiring, a drive ground terminal, and the like. Is omitted.

As shown in FIG. 1, the resonator element 100 according to the first embodiment is formed on the surface of the base 10, the pair of vibrating arms 12 and 13 extending side by side from the base 10, and the vibrating arms 12 and 13. And a groove portion 42.
The resonator element 100 is formed by etching a piezoelectric substrate. For example, the resonator element 100 is formed of a crystal, particularly a Z-cut crystal substrate, as the piezoelectric substrate. Thereby, the resonator element 100 can exhibit excellent vibration characteristics. A Z-cut quartz substrate is a quartz substrate whose thickness direction is the Z axis (optical axis) of quartz. The Z-axis preferably coincides with the thickness direction of the Z-cut quartz substrate, but is slightly (for example, less than about 15 °) with respect to the thickness direction from the viewpoint of reducing the frequency temperature change near room temperature. Will tilt.

  The base 10 has a substantially plate shape having a spread in the XY plane and having a thickness in the Z-axis direction. The vibrating arms 12 and 13 are provided side by side in the X-axis direction, and respectively extend from the end portion 11 of the base 10 in the + Y-axis direction in the + Y-axis direction. A substantially rectangular weight portion 32 having a width (length in the X-axis direction) wider than that of the vibrating arms 12 and 13 is provided at the tip of the vibrating arms 12 and 13. By providing the weight portion 32 as described above, it is possible to reduce the size of the resonator element and reduce the frequency of flexural vibration of the vibrating arm. The weight portion 32 may have a plurality of widths (length in the X-axis direction) stepwise as necessary, or may be omitted.

  In the vibrating arms 12 and 13, bottomed groove portions 42 that are open to the main surfaces are formed on both main surfaces of the front and back surfaces. These groove portions 42 are formed to extend in the Y-axis direction and have the same shape. Further, in the cross section (XZ plane) in the direction intersecting with the extending direction of the vibrating arms 12 and 13, the groove 42 has a width (length in the X-axis direction) of the opening as shown in FIG. A curved shape is formed between the side surface portion 46 and the bottom surface portion 44.

  By forming such a groove portion 42 in the vibrating arms 12 and 13, the distance between the side surface (YZ surface) of the vibrating arms 12 and 13 and the side surface portion 46 of the groove portion 42 can be reduced, so that the electric field efficiency is increased. Thus, the resonator element 100 with low impedance can be obtained. Further, since the space between the side surface portion 46 and the bottom surface portion 44 has a curved shape, stress is not concentrated between the side surface portion 46 and the bottom surface portion 44 even when an impact is applied, and the vibrating arms 12 and 13 are not affected. Can reduce the risk of breakage, and the vibration piece 100 having excellent impact resistance can be obtained. In this embodiment, the groove portion 42 is formed on both main surfaces of the vibrating arms 12 and 13. However, the present invention is not limited to this, and one of the main surfaces of the vibrating arms 12 and 13 is either one. It may be formed only on the main surface. In that case, the same effect as described above can be obtained.

  In the vibrating piece 100, when a driving voltage is applied to the driving electrode, an electric field is appropriately generated in the vibrating arms 12 and 13 of the vibrating piece 100, and the pair of vibrating arms 12 and 13 approach and separate from each other. To bend and vibrate at a predetermined frequency in the in-plane direction (XY plane direction).

Second Embodiment
(Manufacturing method of vibrating piece)
Next, as an example of the method for manufacturing a resonator element according to the second embodiment of the present invention, a method for manufacturing the resonator element 100 formed from the quartz crystal substrate 110 as a wafer will be given and described with reference to FIGS. .
FIG. 3 is a process diagram in the method for manufacturing a resonator element according to the second embodiment of the invention. FIG. 4 is a schematic cross-sectional view taken along line AA in FIG. 1 for explaining the groove forming step. FIG. 5 is a schematic configuration diagram showing the configuration of the dry etching apparatus.

  As shown in FIG. 3, the manufacturing method for forming the resonator element 100 from the quartz substrate 110 includes a groove forming step (Step 1), an outer shape forming step (Step 2), an electrode forming step (Step 3), and a frequency adjusting step ( Step 4) and a dividing step (Step 5) are included.

[Groove Forming Step (Step 1)]
The groove forming step (Step 1) includes a mask forming step, a supporting substrate fixing step, a dry etching step, and a supporting substrate separating step.

[Mask formation process]
In the mask formation step, first, the underlayer 120 is formed on both the main surfaces of the front and back surfaces of the quartz crystal substrate 110. FIG. 4A is a schematic cross-sectional view after the underlayer 120 is formed on the quartz substrate 110. The underlayer 120 can be formed by sputtering, CVD (Chemical Vapor Deposition), electroless plating, or the like. As a material of the underlayer 120, for example, gold (Au), copper (Cu), titanium tungsten (TiW), chromium (Cr), nickel chromium (NiCr), aluminum (Al), or the like can be used. An adhesion layer (not shown) for improving the adhesion between the quartz crystal substrate 110 and the foundation layer 120 may be provided. In this embodiment, a base layer 120 having a thickness of about 100 nm is formed of gold (Au) on a quartz substrate 110 having a thickness of about 110 μm with a chromium (Cr) adhesion layer interposed therebetween.

  Next, the resist 130 is patterned on one main surface (+ Z-axis direction) using photolithography. FIG. 4B is a schematic cross-sectional view after patterning. The resist 130 is uniformly applied with a thickness of approximately 25 μm on one main surface (+ Z-axis direction) of the quartz crystal substrate 110 using, for example, a coater. The resist 130 applied to the quartz substrate 110 is exposed through a photomask (not shown) using an exposure apparatus such as a contact aligner or a proximity aligner. Thereafter, by developing the resist 130, the resist 130 patterned into the shape of the groove 42 in plan view is formed.

  Next, the quartz substrate 110 is etched to form a metal layer 140 that serves as a mask when forming the groove 42 on both main surfaces of the front and back surfaces of the quartz substrate 110. FIG. 4C is a schematic cross-sectional view after the metal layer 140 is formed. The metal layer 140 is formed on the base layer 120 exposed by using the patterned resist 130 as a mask and the base layer 120 on the other main surface (−Z axis direction) side by a plating technique. The metal layer 140 of the present embodiment is formed with a thickness of approximately 15 μm by electroless plating of nickel (Ni).

Next, the resist 130 and the base layer 120 are removed to form a metal layer 140 that serves as a metal mask. FIG. 4D is a schematic cross-sectional view after the resist 130 and the base layer 120 are peeled off. By removing the resist 130 that is no longer needed and used as a mask for the underlayer 120 in the process of forming the metal layer 140, and removing the exposed underlayer 120, an opening is formed in the shape of the groove portion 42 in plan view to be a metal mask. A metal layer 140 having the above pattern is formed. As a method for removing the resist 130, a wet etching method using a resist remover, a dry etching method using ozone or plasma, or the like can be used. As a peeling method of the underlayer 120, a dry etching method using a reactive gas that reacts with the material used for the underlayer 120, a wet etching method in which the material used for the underlayer 120 is immersed in a liquid that corrodes and dissolves, etc. Can be used.
Through the above steps, a metal mask is formed on one main surface (+ Z-axis direction) of the quartz substrate 110 by the metal layer 140 having a pattern opened in the shape of the groove 42 in plan view.

[Support substrate fixing process]
In the supporting substrate fixing step, the quartz crystal substrate 110 on which the metal layer 140 is formed is fixed on a supporting substrate 150 such as silicon via a fixing member 160 such as a double-sided adhesive tape. FIG. 4E is a schematic cross-sectional view after the crystal substrate 110 is fixed on the support substrate 150. In a state where the quartz substrate 110 is bonded to the support substrate 150 via the fixing member 160, the quartz substrate 110 is carried into a vacuum container of a dry etching apparatus and placed on a stage provided in the vacuum container. As described above, the quartz substrate 110 according to the present embodiment has a very thin thickness of approximately 110 μm. However, the quartz substrate 110 is carried in by being attached to the support substrate 150 having a sufficient strength of 600 to 800 μm. It is possible to reliably prevent the quartz substrate 110 from being damaged by an external force that sometimes acts.

[Dry etching process]
In the dry etching process, etching is performed using a dry etching apparatus as shown in FIG. 5 to form the groove 42 using the metal layer 140 as a mask. As an example of the dry etching apparatus, an ICP (Inductive Coupling Plasma) type (inductive coupling type) RIE (Reactive Ion Etching) apparatus is used. FIG. 4F is a schematic cross-sectional view after the crystal substrate 110 is etched to form the groove 42.

In the dry etching process, first, a support substrate 150 on which a crystal substrate 110 is fixed is fixed with high adhesion by electrostatic adsorption on a stage provided in a vacuum vessel of a dry etching apparatus. Thereafter, the inside of the vacuum vessel is depressurized to about 1.0 Pa, and an etching gas containing hexafluoroethane (C ₂ F ₆ ) and helium (He) is supplied into the vacuum vessel from the gas inlet.

  Next, by flowing a high-frequency large current from a high-frequency power source through a coil provided in the upper part of the vacuum vessel, the hexafluoroethane is decomposed by a high voltage and a high-frequency magnetic field to generate inductively coupled plasma. Thereafter, when the potential of the stage is set to a negative potential, positive ions of inductively coupled plasma are attracted to the stage and collide with the quartz substrate 110, and the quartz substrate 110 that is not masked by the metal layer 140 is etched, and the groove 42. Is formed. Further, the reaction product containing fluorine (F), carbon (C), and silicon (Si) generated at that time is exhausted by a vacuum pump, but a part of the reaction product adheres to the side surface portion 46 of the groove portion 42 etched as a protective film. To do. This protective film serves to prevent etching in the direction (X-axis direction, Y-axis direction, etc.) intersecting the thickness direction (Z-axis direction) of the quartz crystal substrate 110.

  In the initial state of etching, the pressure (etching gas pressure) in the vacuum vessel of the dry etching apparatus is maintained at about 1.0 Pa, and a protective film is formed on the side surface portion 46 of the groove portion 42, while the thickness direction ( Etching in the Z-axis direction). Therefore, the width (length in the X-axis direction) of the opening of the groove 42 is substantially constant. Thereafter, as the etching progresses, the pressure in the vacuum chamber (etching gas pressure) is increased to adjust the plasma mean free path so that the side etching component to the side surface portion 46 is increased, resulting in isotropic etching. .

Therefore, the width (length in the X-axis direction) of the groove 42 is wider on the bottom surface 44 side than the opening. Thereafter, as the depth of the groove portion 42 (the length in the Z-axis direction) becomes deeper, the side etching component decreases, and a curved shape is formed between the side surface portion 46 and the bottom surface portion 44 of the groove portion 42.
Etching is terminated when the depth of the groove 42 (the length in the Z-axis direction) reaches a predetermined depth.

  Although the case where the inductive coupling type is used for the dry etching apparatus has been described here, a capacitive coupling type (parallel plate type) using a counter electrode for the coil portion may be used for the dry etching apparatus.

[Support substrate separation process]
In the support substrate separation step, the crystal substrate 110 and the support substrate 150 that have been etched to form the groove portions 42 are immersed in a liquid that corrodes and dissolves the material used for the metal layer 140, and the metal layer 140 is dissolved, thereby the crystal substrate 110 and the support substrate 150 are separated.
Through the above steps, the groove 42 can be formed on one main surface of the quartz crystal substrate 110. In addition, when forming the groove part 42 in both the main surfaces of the front and back of the quartz substrate 110, the groove part formation process mentioned above is performed on the other main surface of the quartz substrate 110, so that both the front and back main surfaces of the quartz substrate 110 are formed. The groove part 42 can be formed.

  As described above, in the groove forming step (Step 1) according to the present embodiment, after forming a metal mask on the quartz crystal substrate 110 in the mask forming step, the etching gas pressure of the dry etching apparatus is increased in the dry etching step, and the plasma mean free path. Is adjusted to be shorter, and dry etching is continuously performed while forming a protective film on the side surface portion 46 of the groove portion 42. Therefore, the width (length in the X-axis direction) of the groove 42 can be expanded from the opening toward the bottom surface 44, and the curved portion can be formed between the side surface 46 and the bottom surface 44. . Accordingly, the distance between the side surface portion 46 of the groove portion 42 and the side surfaces of the vibrating arms 12 and 13 can be narrowed, and the electric field efficiency is increased, so that the vibrating piece 100 with low impedance can be manufactured. In addition, since a shape including a curved shape is formed between the side surface portion 46 and the bottom surface portion 44, even if an impact is applied, stress is not concentrated between the side surface portion 46 and the bottom surface portion 44, and vibration is generated. The possibility that the arms 12 and 13 are damaged can be reduced, and the resonator element 100 having excellent impact resistance can be manufactured.

[Outer shape forming step (Step 2)]
In the outer shape forming step (Step 2), the same process as the above-described groove forming step (Step 1) is repeated on the quartz substrate 110 on which the groove portion 42 is formed, and the outer shape of the resonator element 100 is formed. First, in a mask formation step, a metal mask having a pattern in which the outer shape of the resonator element 100 is opened is formed on the quartz substrate 110 on which the groove 42 is formed. Thereafter, in the dry etching process, etching is performed while maintaining the pressure (etching gas pressure) in the vacuum vessel of the dry etching apparatus at about 1.0 Pa. By maintaining the pressure in the vacuum vessel at about 1.0 Pa, etching is performed while stably forming a protective film on the outer shape side wall of the vibrating piece 100, thereby preventing side etching and reducing the outer shape of the vibrating piece 100. It can be processed so that the side wall of this is substantially vertical.

Since the side wall (YZ plane) in the direction (X-axis direction) orthogonal to the vibration direction of the resonator element 100 is substantially vertical, it can be vibrated in a substantially vibration direction, so that an increase in impedance due to vibration leakage is reduced. be able to. Etching is completed until the crystal substrate 110 is penetrated in the thickness direction (Z-axis direction).
Thus, the vibrating piece 100 in which the groove 42 is formed on the surface of the vibrating arms 12 and 13 is formed.

[Electrode formation step (Step 3)]
In the electrode formation step (Step 3), electrode films, for example, gold (Au) with chromium (Cr) as a base are deposited on both the front and back main surfaces and side walls of the resonator element 100 and the bottom surface portion 44 and the side surface portion 46 of the groove portion 42. The film is formed by sputtering or the like. After applying the resist, an electrode pattern is formed by photolithography, and the electrode film is wet-etched so that electrodes such as a drive signal electrode, a drive signal wiring, a drive signal terminal, a drive ground electrode, a drive ground wiring, and a drive ground terminal Is formed. At the same time, electrodes for frequency adjustment may be formed on both main surfaces of the front and back surfaces of the weight portion 32 provided at the tip portions of the vibrating arms 12 and 13.

[Frequency adjustment step (Step 4)]
In the frequency adjustment step (Step 4), while monitoring the frequency of the resonator element 100, the metal film or the like formed on the weight portion 32 is irradiated with laser light to partially evaporate the metal film. Thus, the desired frequency is adjusted.

[Division process (Step 5)]
In the dividing step (Step 5), the vibrating piece 100 is divided into pieces by dividing the vibrating piece 100 from the frame portion of the crystal substrate 110.
Through the above steps, the resonator element 100 in which the electrode is formed and the frequency is adjusted is completed.

<Third Embodiment>
(Gyro element)
Next, a gyro element 200 having an H-type structure as a resonator element according to a third embodiment of the present invention will be described as an example with reference to FIG.
FIG. 6 is a schematic plan view showing the structure of the gyro element according to the third embodiment of the present invention. The gyro element 200 includes a detection signal electrode, a detection signal wiring, a detection signal terminal, a detection ground electrode, a detection ground wiring, a detection ground terminal, a drive signal electrode, a drive signal wiring, a drive signal terminal, a drive ground electrode, and a drive ground. Wiring, a drive ground terminal, and the like are provided, but are omitted in FIG. 6 for convenience of explanation.

  As shown in FIG. 6, the gyro element 200 according to the third embodiment includes a base 20 integrally formed by processing a base material (material constituting a main part), and an end of the base 20 in the Y-axis direction. A pair of drive vibrating arms 12a and 12b extending along the Y axis so as to be parallel from one end 10b of the portions 10a and 10b, and along the Y axis from the other end 10a of the base 20 And a pair of detection vibrating arms 14a and 14b extending in parallel.

  The drive vibrating arms 12a and 12b and the detection vibrating arms 14a and 14b are formed with bottomed grooves 42a, 42b, 44a, and 44b that are open to the main surfaces on both the front and back main surfaces. These groove portions 42a, 42b, 44a, 44b are formed extending in the Y-axis direction. Further, the groove portions 42a, 42b, 44a, 44b are widths (lengths in the X-axis direction) of the groove portions 42a, 42b, 44a, 44b in a cross section (XZ plane) in a direction intersecting with the extending direction of each vibrating arm. Is formed so as to spread from the opening toward the bottom surface, and a curved shape is formed between the side surface and the bottom surface. Therefore, the gyro element 200 having low impedance and excellent impact resistance can be obtained.

  Moreover, the 1st connection part 20a extended from the base 20 and the 1st support part 22a connected to the 1st connection part 20a, and the 2nd connection part 20b extended in the opposite direction to the 1st connection part 20a from the base 20 And a second support portion 22b connected to the second connection portion 20b. Furthermore, the first support portion 22a and the second support portion 22b are integrally connected on the drive vibrating arms 12a and 12b side to form a fixed frame portion 24. The gyro element 200 is fixed to a substrate such as a package (not shown) at a predetermined position of the fixed frame portion 24.

  Note that weight portions 32a and 32b are provided at the distal ends of the drive vibration arms 12a and 12b, and weight portions 34a and 34b are provided at the distal ends of the detection vibration arms 14a and 14b. By providing the weight portions 32a, 32b, 34a, 34b, the length in the extending direction of the drive vibration arms 12a, 12b and the detection vibration arms 14a, 14b (the length in the Y-axis direction) is shortened with the same resonance frequency. Therefore, the gyro element 200 can be downsized. Further, the resonance frequencies of the drive vibrating arms 12a and 12b and the detection vibrating arms 14a and 14b can be lowered. Furthermore, the weight portions 32a, 32b, 34a, 34b may have a plurality of widths (lengths in the X-axis direction) as necessary, or may be omitted. The weight portions 32a, 32b, 34a, 34b are provided with a mass portion (not shown) formed of a metal film or the like, and a part of the mass portion is removed with a laser beam or the like, thereby driving vibration arms 12a, 12b. And the resonance frequency of the detection vibrating arms 14a and 14b can be adjusted.

  The center of the base 20 can be the center of gravity of the gyro element 200. The X axis, the Y axis, and the Z axis are orthogonal to each other and pass through the center of gravity. The outer shape of the gyro element 200 can be axisymmetric with respect to a virtual center line in the Y-axis direction passing through the center of gravity. Thereby, the outer shape of the gyro element 200 is balanced, which is preferable because the characteristics of the gyro element 200 are stabilized and the detection sensitivity is improved.

[Gyro element operating principle]
Next, the operation principle of the gyro element 200 will be described with reference to FIG.
FIG. 7 is a schematic plan view for explaining the operation principle of the gyro element according to the third embodiment of the present invention.
When a predetermined AC voltage is applied to the drive electrode in the drive mode, the drive vibrating arms 12a and 12b bend in the opposite direction in the XY plane, that is, in the direction approaching and separating from each other, as shown in FIG. Vibrates (in-plane mode vibration).

  In this state, when the gyro element 200 applies an angular velocity ω that rotates about the Y axis that is the extending direction of the drive vibrating arms 12a and 12b, due to the action of the Coriolis force generated according to the angular velocity ω, FIG. As shown in FIG. 4, the drive vibrating arms 12a and 12b bend and vibrate (out-of-plane mode vibration) in directions opposite to each other in the out-of-plane direction perpendicular to the main surface, that is, the Z-axis direction. Resonating with the vibration in the Z-axis direction, the detection vibrating arms 14a and 14b are flexibly vibrated (out-of-plane mode vibration) in the Z-axis direction in opposite directions. At this time, the vibration direction of the detection vibrating arms 14a and 14b is in the opposite phase to the vibration direction of the drive vibrating arms 12a and 12b.

  That is, when the drive vibration arm 12a vibrates in the + Z axis direction, the drive vibration arm 12b becomes an out-of-plane mode bending vibration that vibrates in the −Z axis direction. The bending vibrations in the out-of-plane mode of the drive vibration arms 12a and 12b are transmitted to the detection vibration arms 14a and 14b via the base 20, thereby resonating the detection vibration arms 14a and 14b, and the detection vibration arm 14a is in the −Z-axis direction. , The detection vibrating arm 14b becomes an out-of-plane mode bending vibration that vibrates in the + Z-axis direction.

  In this detection mode, the angular velocity ω applied to the gyro element 200 is obtained by taking out the amount of charge generated between the detection electrodes of the detection vibrating arms 14a, 14b.

<Fourth embodiment>
(Gyro element)
Next, a double T-type gyro element 300 as a resonator element according to the fourth embodiment will be described as an example with reference to FIG.
FIG. 8 is a schematic plan view showing the structure of the gyro element according to the fourth embodiment of the present invention. The gyro element 300 includes a detection signal electrode, a detection signal wiring, a detection signal terminal, a detection ground electrode, a detection ground wiring, a detection ground terminal, a drive signal electrode, a drive signal wiring, a drive signal terminal, a drive ground electrode, and a drive ground. Wiring, a drive ground terminal, and the like are provided, but are omitted in FIG. 8 for convenience of explanation.

  The gyro element 300 according to the fourth embodiment is an “out-of-plane detection type” sensor element that detects an angular velocity around the Z-axis, and is composed of quartz, and thus exhibits excellent vibration characteristics (frequency characteristics). This is a gyro element 300 that can be used.

  Such a gyro element 300 includes a so-called double T-shaped vibrating body 4, a first support portion 51 and a second support portion 52 as support portions for supporting the vibrating body 4, and the vibrating body 4 and the first support portion. The first beam 61, the second beam 62, the third beam 63, and the fourth beam 64 that connect the 51 and the second support portion 52.

  The vibrating body 4 has an extension in the XY plane and has a thickness in the Z-axis direction. Such a vibrating body 4 includes a base 41 located at the center, a first detection vibrating arm 321 and a second detection vibrating arm 322 extending from the base 41 to both sides along the Y-axis direction, and an X from the base 41. The first connecting arm 331 of the base 41 extending to both sides along the axial direction, the second connecting arm 332 of the base 41, and both sides along the Y-axis direction from the distal end of the first connecting arm 331 of the base 41 The first drive vibrating arm 341 and the second drive vibrating arm 342 that extend in the direction from the tip of the second connecting arm 332 of the base 41 and the third drive vibrating arm that extends to both sides along the Y-axis direction 343, and a fourth drive vibrating arm 344. In addition, the 1st connection arm 331 of the base 41 and the 2nd connection arm 332 of the base 41 are handled as a part of base.

  The first and second detection vibrating arms 321 and 322, the base 41 of the first, second, third, and fourth drive vibrating arms 341, 342, 343, and 344, the first connecting arm 331, and the second connecting arm 332; At the distal end portion on the other end side opposite to the one end to be connected, substantially rectangular weight portions 325, 326, 345, 346, 347, 348 having a width wider than the proximal end side are provided. By providing the weight portions 325, 326, 345, 346, 347, and 348, the angular velocity detection sensitivity of the gyro element 300 is improved.

  In addition, bottomed grooves 358 and 359 that are open to the main surfaces are formed on both main surfaces of the front and back surfaces of the first detection vibrating arm 321 and the second detection vibrating arm 322. These groove portions 358 and 359 are formed to extend in the Y-axis direction and have the same shape. In addition, the grooves 358 and 359 have a width (length in the X-axis direction) of the grooves 358 and 359 in a cross section (XZ plane) in a direction intersecting with the extending direction of the first detection vibrating arm 321 and the second detection vibrating arm 322. ) Is widened from the opening toward the bottom surface, and a curved shape is formed between the side surface and the bottom surface. Therefore, the gyro element 300 having low impedance and excellent impact resistance can be obtained. In addition, the structure dug from the main surface side of either the front surface or the back surface may be sufficient as a groove part.

  The first and second support parts 51 and 52 extend along the X-axis direction, and the vibrating body 4 is located between the first and second support parts 51 and 52. . In other words, the first and second support portions 51 and 52 are disposed so as to face each other along the Y-axis direction with the vibrating body 4 interposed therebetween. The first support 51 is connected to the base 41 via the first beam 61 and the second beam 62, and the second support 52 is connected to the base 41 via the third beam 63 and the fourth beam 64. It is connected with.

  The first beam 61 passes between the first detection vibrating arm 321 and the first drive vibrating arm 341 to connect the first support portion 51 and the base 41, and the second beam 62 is connected to the first detection vibrating arm 321. The first support portion 51 and the base portion 41 are connected to each other through the third drive vibration arm 343, and the third beam 63 passes between the second detection vibration arm 322 and the second drive vibration arm 342 to connect the first support portion 51 and the base portion 41. The second support portion 52 and the base portion 41 are connected, and the fourth beam 64 connects the second support portion 52 and the base portion 41 through the space between the second detection vibrating arm 322 and the fourth drive vibrating arm 344.

  Each of the first beam 61 to the fourth beam 64 is formed in an elongated shape having a meandering portion extending along the Y-axis direction while reciprocating along the X-axis direction, and thus has elasticity in all directions. Yes. Therefore, even if an impact is applied from the outside, each beam 61, 62, 63, 64 has an action of absorbing the impact, so that detection noise caused by this can be reduced or suppressed.

[Gyro element operating principle]
Next, the operation principle of the gyro element 300 will be described.
The gyro element 300 having such a configuration detects the angular velocity ω around the Z axis as follows. When an electric field is generated between the drive signal electrode (not shown) and the drive ground electrode (not shown) in a state where the angular velocity ω is not applied, the gyro element 300 causes the drive vibrating arms 341, 342, 343, and 344 to Bending vibration is performed in the X-axis direction. At this time, the first and second drive vibrating arms 341 and 342 and the third and fourth drive vibrating arms 343 and 344 perform plane-symmetric vibration with respect to the YZ plane passing through the center point (center of gravity). The base 41, the first and second connecting arms 331 and 332 of the base 41, and the first and second detection vibrating arms 321 and 322 hardly vibrate.

  When an angular velocity ω is applied to the gyro element 300 around the Z axis in the state where the drive vibration is performed, the drive vibration arms 341, 342, 343, 344 and the connection arms 331, 332 of the base 41 are connected to the Coriolis in the Y axis direction. Thus, the detected vibration in the X-axis direction is excited in response to the vibration in the Y-axis direction. Then, the angular velocity ω is obtained by detecting the distortion of the detection vibrating arms 321 and 322 generated by this vibration as a detection signal.

<Fifth Embodiment>
(Vibrator)
Next, a vibrator 400 to which the resonator element 100 according to the first embodiment of the invention is applied will be described with reference to FIG.
9A and 9B are schematic views showing the structure of a vibrator provided with the resonator element according to the embodiment of the invention. FIG. 9A is a schematic plan view, and FIG. 9B is a diagram in FIG. It is a schematic sectional drawing in the BB line. In FIG. 9A, for convenience of explanation of the internal configuration of the vibrator 400, a state in which the lid member 456 is removed is illustrated.
The vibrator 400 includes a vibrating piece 100, a rectangular box-shaped package 450 for housing the vibrating piece 100, and a lid member 456 made of glass, ceramic, metal, or the like. In addition, the inside of the cavity 470 that accommodates the resonator element 100 is a substantially vacuum reduced pressure atmosphere.

  As shown in FIG. 9B, the package 450 is formed by stacking a first substrate 451, a second substrate 452, and mounting terminals 445. A plurality of mounting terminals 445 are provided on the outer low surface of the first substrate 451. In addition, a plurality of connection electrodes 447 that are electrically connected to the mounting terminals 445 are provided at predetermined positions on the upper surface of the first substrate 451 through through electrodes and interlayer wirings (not shown). The second substrate 452 is an annular body from which a central portion is removed, and a cavity 470 that accommodates the resonator element 100 is provided.

  As described above, the first substrate 451 and the second substrate 452 of the package 450 described above are made of an insulating material. Such a material is not particularly limited, and various ceramics such as oxide ceramics, nitride ceramics, and carbide ceramics can be used. In addition, each electrode, terminal provided in the package 450, or a wiring pattern or an in-layer wiring pattern for electrically connecting them is generally made of a metal wiring material such as tungsten (W) or molybdenum (Mo). It is provided by screen printing on an insulating material and baking, followed by plating with nickel (Ni), gold (Au) or the like.

  The lid member 456 is preferably made of a light-transmitting material, such as borosilicate glass, and is hermetically sealed by bonding with the sealing member 458. Thereby, after sealing the lid of the package 450, laser light is irradiated from the outside to the vicinity of the tip of the vibrating piece 100 via the lid member 456, and a part of the electrode provided here is evaporated to thereby reduce the mass. The frequency can be adjusted. When such frequency adjustment is not performed, the lid member 456 can be formed of a metal material such as a Kovar alloy.

  The resonator element 100 housed in the cavity 470 of the package 450 is provided with first and second conductive pads (not shown) provided on the base 10 and 2 provided on the upper surface of the first substrate 451 of the package 450. The two connection electrodes 447 are aligned so as to correspond to each other, and are joined via the joining member 442. The bonding member 442 can be electrically connected and mechanically bonded by using a conductive bonding member such as a bump made of metal or solder or a conductive adhesive, for example.

<Sixth Embodiment>
(Oscillator)
Next, an oscillator 500 to which the resonator element 100 according to the first embodiment of the invention is applied will be described with reference to FIG.
FIG. 10 is a schematic cross-sectional view illustrating the structure of an oscillator including the resonator element according to the embodiment of the invention.
The oscillator 500 includes a resonator element 100, an IC chip (chip component) 562 as an electronic component including a circuit that drives the resonator element 100, a package 560 that houses the resonator element 100 and an IC chip 562 as an electronic component, and glass. , And a lid member 556 made of ceramic, metal, or the like. Note that the inside of the cavity 570 that accommodates the resonator element 100 is in a substantially vacuum reduced pressure atmosphere.

As illustrated in FIG. 10, the package 560 is formed by stacking a first substrate 551, a second substrate 552, a third substrate 553, a fourth substrate 554, and mounting terminals 546. ing. The package 560 includes a cavity 570 that opens to the upper surface and a cavity 572 that opens to the lower surface.
A plurality of mounting terminals 546 are provided on the outer bottom surface of the fourth substrate 554. In addition, the mounting terminal 546 is electrically connected to the connection electrode 547 provided on the upper surface of the first substrate 551 and the connection electrode 548 provided on the lower surface of the third substrate 553 with a through electrode or interlayer wiring (not shown). Is electrically connected.

  The cavity 570 of the package 560 is provided on the upper surfaces of the first and second conductive pads (not shown) of the resonator element 100 and the first substrate 551 of the package 560 in the same manner as the vibrator 400 of the present embodiment. The two connection electrodes 547 are aligned so as to correspond to each other, bonded through the bonding member 542, and then bonded by a sealing member 558 such as borosilicate glass, thereby being hermetically sealed.

On the other hand, an IC chip 562 is accommodated in the cavity 572 of the package 560, and the IC chip 562 is fixed to the lower surface of the first substrate 551 via a bonding member 543 such as a brazing material or an adhesive. ing. A plurality of connection electrodes 548 are provided in the cavity 572. The connection electrode 548 is electrically connected to the IC chip 562 by a bonding wire 544. The cavity 572 is filled with a resin material 564, and the IC chip 562 is sealed with the resin material 564.
The IC chip 562 has a drive circuit (oscillation circuit) for controlling the driving of the resonator element 100. When the resonator element 100 is driven by the IC chip 562, a signal having a predetermined frequency can be extracted.

<Seventh embodiment>
(Electronics)
Next, an electronic apparatus to which the resonator element 100 according to the first embodiment of the invention is applied will be described with reference to FIGS.
FIG. 11 is a perspective view illustrating a configuration of a mobile (or notebook) personal computer as an electronic apparatus including the resonator element according to the embodiment of the invention. In this figure, a personal computer 1100 includes a main body portion 1104 provided with a keyboard 1102 and a display unit 1106 provided with a display portion 1000. The display unit 1106 is rotated with respect to the main body portion 1104 via a hinge structure portion. It is supported movably. Such a personal computer 1100 incorporates the resonator element 100.

  FIG. 12 is a perspective view illustrating a configuration of a mobile phone (including PHS) as an electronic apparatus including the resonator element according to the embodiment of the invention. In this figure, a cellular phone 1200 includes a plurality of operation buttons 1202, a mouthpiece 1204, and a mouthpiece 1206, and a display unit 1000 is disposed between the operation buttons 1202 and the earpiece 1204. Such a cellular phone 1200 incorporates the resonator element 100.

FIG. 13 is a perspective view illustrating a configuration of a digital camera as an electronic apparatus including the resonator element according to the embodiment of the invention. In this figure, connection with an external device is also simply shown. Here, an ordinary camera sensitizes a silver salt photographic film with a light image of a subject, whereas a digital camera 1300 captures a light image of a subject by photoelectrically converting it with an image sensor such as a CCD (Charge Coupled Device). A signal (image signal) is generated.
A display unit 1000 is provided on the back surface of a case (body) 1302 in the digital camera 1300, and is configured to perform display based on an imaging signal from the CCD. The display unit 1000 displays a subject as an electronic image. Function as. A light receiving unit 1304 including an optical lens (imaging optical system), a CCD, and the like is provided on the front side (the back side in the drawing) of the case 1302.

  When the photographer confirms the subject image displayed on the display unit 1000 and presses the shutter button 1306, the CCD image pickup signal at that time is transferred and stored in the memory 1308. In the digital camera 1300, a video signal output terminal 1312 and an input / output terminal 1314 for data communication are provided on the side surface of the case 1302. As shown in the drawing, a television monitor 1330 is connected to the video signal output terminal 1312 and a personal computer (PC) 1340 is connected to the input / output terminal 1314 for data communication as necessary. Further, the imaging signal stored in the memory 1308 is output to the television monitor 1330 or the personal computer 1340 by a predetermined operation. Such a digital camera 1300 incorporates a vibrating piece 100.

  Note that the electronic apparatus including the resonator element 100 according to the first embodiment of the invention includes a personal computer (mobile personal computer) 1100 in FIG. 11, a mobile phone 1200 in FIG. 12, and a digital camera 1300 in FIG. 13. , For example, inkjet type ejection device (for example, inkjet printer), laptop personal computer, TV, video camera, video tape recorder, car navigation device, pager, electronic notebook (including communication function), electronic dictionary, calculator, electronic Game equipment, word processor, workstation, video phone, security TV monitor, electronic binoculars, POS terminal, medical equipment (eg electronic thermometer, blood pressure monitor, blood glucose meter, electrocardiogram measuring device, ultrasonic diagnostic device, electronic endoscope), Fish finder, each Measuring instruments, gauges (e.g., gages for vehicles, aircraft, and ships), can be applied to a flight simulator.

<Eighth Embodiment>
(Moving body)
Next, a moving body to which the resonator element 100 according to the first embodiment of the invention is applied will be described with reference to FIG.
FIG. 14 is a perspective view schematically showing an automobile as a moving body including the resonator element according to the embodiment of the invention. In this figure, the resonator element 100 is built in an electronic control unit 1402 that controls a tire 1403 and mounted on a vehicle body 1401.
The automobile 1400 includes the resonator element 100 according to the embodiment of the present invention. For example, a keyless entry, an immobilizer, a car navigation system, a car air conditioner, an antilock brake system (ABS), an airbag, The present invention can be widely applied to electronic control units (ECUs) 1402 such as tire pressure monitoring systems (TPMS), engine controls, battery monitors for hybrid vehicles and electric vehicles, and vehicle body posture control systems.

  As described above, the resonator elements 100, 200, 300, the vibrator 400, the oscillator 500, the electronic devices 1100, 1200, 1300, and the moving body 1400 according to the embodiments of the present invention have been described based on the illustrated embodiments. The invention is not limited to this, and the configuration of each unit can be replaced with any configuration having the same function. In addition, any other component may be added to the present invention. Moreover, you may combine each embodiment suitably.

  DESCRIPTION OF SYMBOLS 10 ... Base part, 11 ... End part, 12, 13 ... Vibrating arm, 32 ... Weight part, 42 ... Groove part, 44 ... Bottom part, 46 ... Side part, 100 ... Vibrating piece, 110 ... Quartz substrate, 120 ... Underlayer, DESCRIPTION OF SYMBOLS 130 ... Resist, 140 ... Metal layer, 150 ... Support substrate, 160 ... Fixing member, 200, 300 ... Gyro element, 400 ... Vibrator, 500 ... Oscillator, 1100 ... Personal computer, 1200 ... Mobile phone, 1300 ... Digital camera 1400 ... an automobile.

Claims (6)

The base,
A pair of vibrating arms extending side by side from the base;
A groove formed on the surface of the vibrating arm,
In the cross section in the direction intersecting the extending direction, the groove portion,
A resonator element characterized in that a width of the groove portion is formed so as to expand from an opening portion toward a bottom surface portion side, and a curved shape is formed between the side surface portion and the bottom surface portion. A vibration piece according to claim 1, wherein the vibration piece is formed from a wafer.
Having a groove forming step of forming a groove in the wafer;
The groove forming step includes
A mask forming step of forming a metal mask on the wafer;
In a dry etching apparatus, a dry etching step of continuously dry etching while forming a protective film on the side surface of the groove,
A method of manufacturing a resonator element, comprising: The resonator element according to claim 1,
A package for housing the resonator element;
A vibrator characterized by comprising: The resonator element according to claim 1,
An electronic component including a circuit for driving the resonator element;
A package for housing the vibrating piece and the electronic component;
An oscillator comprising:   An electronic device comprising the resonator element according to claim 1.   A moving body comprising the resonator element according to claim 1.

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