JP2016085191A - Vibration element, manufacturing method of the same, electronic device, electronic apparatus and movable body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration element capable of suppressing variations of a CI value due to unevenness of an outer shape.SOLUTION: A tuning-fork type vibration piece 100 serving as a vibration element comprises: a base portion 110; and drive vibration arms 120 and 130 extending from the base portion 110 and vibrating at a predetermined resonance frequency f. A relation between the resonance frequency f and each thickness t of the drive vibration arms 120 and 130 satisfies 0.004>f×t>0.0008.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vibration element, a method for manufacturing the vibration element, an electronic device using the vibration element, an electronic apparatus, and a moving body.

  Small information devices such as mobile computers and IC cards, mobile communication devices such as mobile phones, and body control, vehicle position detection, or vibration control correction functions (so-called camera shake correction) for digital cameras and digital video cameras, etc. In addition, vibrators and gyro sensors using vibration elements are widely used. For example, in the vibrator, an output signal obtained by vibrating a flexural vibration piece as a vibration element at a predetermined resonance frequency is used as a signal processing timing source. In addition, the gyro sensor detects an electrical signal generated in a part of the gyro vibrating piece by vibration such as shaking or rotation of the object as an angular velocity by a gyro element (gyro vibrating piece), and calculates the rotation angle to calculate the rotation angle of the object. Find the displacement.

  In recent years, along with the downsizing of electronic devices using these vibrating elements, the vibrators and gyro sensors used for them are also required to be downsized. As the vibrator and gyro sensor are downsized, it is necessary to reduce the size of the vibration element. However, the vibration element is reduced in size so that the CI (Crystal) which shows the ease of vibration can be obtained. Impedance) value increases or varies. Therefore, conventionally, countermeasures for stabilizing or reducing the CI value have been studied and proposed.

  For example, in Patent Document 1, the vibration arm portion of the tuning fork type vibration piece (bending vibration piece) is provided with a groove portion from the front and back surfaces, and by providing cut portions on both side surfaces of the base portion from which the vibration arm portion protrudes. It is disclosed that vibration leakage is suppressed and CI value variation is reduced. Further, in Patent Document 2, by reducing the arm width of the resonating arm of the so-called H-type gyro element from the base (base) to the tip, the stress generated in the resonating arm during vibration is made constant, and the CI value Is disclosed.

JP 2002-261575 A JP 2001-133269 A

  However, as the vibration element is further miniaturized, the above-mentioned countermeasures are not sufficient, and for example, variations in CI values caused by variations in the outer shape cannot be ignored.

  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 vibration element according to this application example includes a base and a drive vibration arm that extends from the base and vibrates at a predetermined resonance frequency f. The resonance frequency f and the drive vibration arm The relationship with the thickness t is 0.004> f × t ² > 0.0008.

  According to this application example, the relationship between the resonance frequency f of the driving vibration arm and the thickness t of the driving vibration arm as described above may cause variation in the outer shape at the time of manufacturing the vibration element. It is possible to reduce the CI value and reduce the variation of the CI value in a small vibration element.

Application Example 2 In the resonator element according to the application example described above, it is preferable that the relationship between the resonance frequency f and the thickness t of the drive vibrating arm is 0.003> f × t ² > 0.001. .

  According to this application example, it is possible to provide a small vibration element that can further reduce the CI value level and further reduce the CI value variation.

  Application Example 3 In the vibration element according to the application example described above, it is preferable that a detection vibrating arm that extends from the base portion is provided.

  According to this application example, there is provided a vibrating element capable of detecting a small angular velocity, in which a driving vibrating arm having a stable CI value and a detecting vibrating arm capable of detecting an angular velocity signal are extended from the base. Is possible.

  Application Example 4 In the resonator element according to the application example described above, the drive vibration arm extends from one end of the base, and the detection vibration arm extends from the other end opposite to the one end of the base. Preferably it is.

  According to this application example, the drive vibration arm and the detection vibration arm extending from the base portion on the opposite side of the drive vibration arm are provided. As described above, since the drive vibration arm and the detection vibration arm are respectively extended from both ends of the base in the same axial direction, the drive system and the detection system are separated. Or the electrostatic coupling between wirings is reduced and the detection sensitivity of angular velocity can be stabilized.

  Application Example 5 The vibration element according to the application example described above includes a pair of adjustment vibration arms that extend from the base and are provided so that the drive vibration arm or the detection vibration arm is positioned inside. Preferably it is.

  According to this application example, in addition to the application example described above, the adjustment vibrating arm for adjusting the leakage output is provided, so that the charge generated in the detection vibrating arm due to the vibration leakage output can be reduced. Can be canceled by the charge generated in

  Application Example 6 In the resonator element according to the application example described above, any one of the drive vibration arm, the detection vibration arm, and the adjustment vibration arm is disposed on the other end side opposite to the one end connected to the base portion. It is preferable that a wide portion is provided.

According to this application example, a predetermined drive vibration or detection vibration is obtained while suppressing an increase in the length of the drive vibration arm, the detection vibration arm, and the adjustment vibration arm, and the adjustment range for suppressing the leakage vibration is wide. Therefore, it is possible to provide a vibration element having a smaller size and higher sensitivity.
The above-mentioned “other end side” refers to the drive vibration arm, the detection vibration arm, and the tip end portion (open end) of the adjustment vibration arm extending from the base.

Application Example 7 A manufacturing method of a vibration element according to this application example is a vibration element having a base and a driving vibration arm having a thickness t that extends from one end of the base and vibrates at a predetermined resonance frequency f. In the manufacturing method, the outer peripheral shape of the drive vibration arm is set so that the relationship between the resonance frequency f and the thickness t of the drive vibration arm satisfies 0.004> f × t ² > 0.0008. And an outer shape forming process using a dry etching method.

  According to this application example, since the outer shape forming step by dry etching is provided, a small vibration element having a relationship between the resonance frequency f of the driving vibration arm and the thickness t of the driving vibration arm as described above can be easily obtained. Can be formed. As a result, it is possible to reduce the CI value of the vibration element and reduce variations in the CI value. Moreover, it is possible to reduce manufacturing variations of the outer shape by the outer shape processing by dry etching.

  Application Example 8 A vibration electronic device according to this application example includes the vibration element according to any one of the application examples, an electronic component including at least a drive circuit that excites the drive vibration arm, the gyro element, and And a package containing at least one of the electronic components.

  According to this application example, it is possible to obtain an electronic device including the vibration element having the effect described in any one of the application examples. In addition, the package-type electronic device having the above-described configuration is advantageous for downsizing and thinning and can have high impact resistance.

  Application Example 9 An electronic apparatus according to this application example includes the vibration element according to any one of the application examples.

  According to this application example, since the vibration element in which the variation in the CI value is reduced, that is, the vibration element with stable vibration characteristics, the electronic apparatus with stable performance can be provided.

  Application Example 10 A moving body according to this application example includes the vibration element according to any one of the application examples described above.

  According to this application example, since the vibration element in which the variation in the CI value is reduced, that is, the vibration element with stable vibration characteristics, it is possible to provide a movable body with stable performance.

The outline of the tuning fork type vibration element as an example of the vibration element concerning a 1st embodiment of the present invention is shown, (a) is a top view and (b) is Drawing 1 (a) AA sectional view. The correlation between CI value fluctuation and f × t ² is shown, (a) is a graph showing the correlation between CI value and f × t ^2, and (b) is the correlation between the CI value fluctuation rate and f × t ^2. Graph. The outline of the H type gyro element as an example of the vibration element concerning a 2nd embodiment of the present invention is shown, (a) is a perspective view and (b) is a top view. It is a figure explaining the electrode structure of the gyro element which concerns on 2nd Embodiment, (a) is CC sectional drawing of FIG.3 (b), (b) is DD sectional drawing of FIG.3 (b). The top view which shows the outline of the double T-type gyro element as an example of the vibration element which concerns on 3rd Embodiment of this invention. 6 is a flowchart showing an outline of a manufacturing process of the resonator element according to the embodiment. 1 is a front sectional view showing a schematic configuration of a gyro sensor as an example of an electronic device according to the invention. (A)-(c) is a perspective view which shows an example of an electronic device provided with a vibration element. The perspective view which shows the motor vehicle as a moving body provided with a vibration element.

  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. 1 and 3 to 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 the “+ side”, The base end side is defined as “− 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”. say.

(First embodiment)
<Vibration element-1>
First, a schematic configuration of the resonator element according to the first embodiment will be described with reference to FIG. FIG. 1A is a plan view schematically showing a schematic configuration of a tuning-fork type vibrating piece as a vibrating element according to the first embodiment. FIG.1 (b) is sectional drawing in the AA line in Fig.1 (a).

  As shown in FIG. 1, a tuning fork type vibrating piece 100 as a vibrating element includes a base 110 and drive vibration arms 120 and 130 as a pair of vibrating arms extending from the base 110 in the + Y-axis direction. It is a piece. The base part 110 has a flat plate shape including a narrow part 111 and a wide part 113 arranged via a constricted part 112. The base 110 may have a shape in which the constricted portion 112 is not provided, that is, a substantially rectangular flat plate shape. The drive vibrating arms 120 and 130 as the vibrating arms are a pair of prismatic vibrating bodies that extend from the one end on the + Y side of the narrow width portion 111 in the base 110 substantially parallel to each other in the Y-axis direction. The base 110 and the drive vibrating arms 120 and 130 constituting the tuning fork type vibrating piece 100 are integrally formed, and quartz is used as a base material. The tuning fork type vibrating piece 100 of the first embodiment is formed by a photolithography method and a dry etching method using a fluorine-based gas or the like.

  The crystal has an X axis called an electric axis, a Y axis called a mechanical axis, and a Z axis called an optical axis. The base material forming the tuning fork type resonator element 100 is cut out along a plane defined by the X-axis and the Y-axis orthogonal to the quartz crystal axis and processed into a flat plate shape, and has a predetermined thickness in the Z-axis direction orthogonal to the plane. have. As the Z-axis, it is possible to use what is cut out by rotating in the range of 0 to 2 degrees around the X-axis. The predetermined thickness is appropriately set depending on the vibration frequency, the outer size, the workability, and the like.

  The drive vibration arm 120 and the drive vibration arm 130 as the vibration arms vibrate in directions opposite to each other along an in-plane direction (X-axis direction) orthogonal to a plane defined by the X axis and the Y axis. That is, when the driving vibration arm 120 is displaced toward the + X axis direction, the driving vibration arm 130 is displaced toward the −X axis direction, and when the driving vibration arm 120 is displaced toward the −X axis direction, the driving vibration arm 130 is displaced. 130 is displaced in the + X-axis direction and vibrates at a frequency of 500 kHz or less.

  The drive vibration arm 120 and the drive vibration arm 130 extended from the base 110 are formed with a thickness t as a dimension in a direction orthogonal to the vibration direction (Z-axis direction). The drive vibrating arm 120 includes a front surface 103c, a back surface 103d provided on the opposite side of the front surface 103c, and side surfaces 103h and 103i that connect the front surface 103c and the back surface 103d. The drive vibrating arm 130 includes a front surface 103g, a back surface 103f provided on the opposite side of the front surface 103g, and side surfaces 103j and 103k that connect the front surface 103g and the back surface 103f.

  Although not shown in the figure, a weight portion as a substantially rectangular wide portion that is wider than the drive vibration arms 120 and 130 (large in the X-axis direction) is formed at the tip of the drive vibration arms 120 and 130. It may be provided. In the configuration in which the drive vibration arms 120 and 130 are provided with the weight portion as the wide portion, predetermined drive vibration can be obtained while suppressing an increase in the length (dimension in the Y-axis direction) of the drive vibration arms 120 and 130. Therefore, the tuning fork type vibrating piece 100 can be downsized.

  Next, the drive electrode of the tuning fork type vibrating piece 100 will be described. The drive electrodes for driving the drive vibrating arms 120 and 130 include first drive electrodes 121a, 121b, 132a, and 132b, and second drive electrodes 122a, 122b, 131a, and 131b. The first drive electrodes 121a, 121b, 132a, 132b, and the second drive electrodes 122a, 122b, 131a, 131b are provided so as to extend from the roots of the drive vibrating arms 120, 130 toward the tip.

  As shown in FIG. 1B, the second drive electrode 122 a is provided on one side surface 103 h of the drive vibrating arm 120 along the extending direction (Y-axis direction) of the drive vibrating arm 120. A second drive electrode 122b is provided on the opposite side surface 103i along the extending direction of the drive vibrating arm 120. Further, a first drive electrode 121a is provided on the front surface 103c of the drive vibration arm 120, and a first drive electrode 121b is provided on the back surface 103d. The first drive electrode 121a and the first drive electrode 121b are electrically connected via the tip of the drive vibrating arm 120 and the like, although not shown. Similarly, the second drive electrode 122a and the second drive electrode 122b are electrically connected via the tip of the drive vibrating arm 120 and the like, though not shown. The first drive electrodes 121a and 121b and the second drive electrodes 122a and 122b are electrically connected to external connection pads (not shown) via wirings (not shown).

  Similarly, the first drive electrode 132a is provided on one side surface 103j of the drive vibrating arm 130 along the extending direction (Y-axis direction) of the drive vibrating arm 130. A first drive electrode 132b is provided on the opposite side surface 103k along the extending direction of the drive vibrating arm 130. Further, a second drive electrode 131a is provided on the front surface 103g of the drive vibration arm 130, and a second drive electrode 131b is provided on the back surface 103f. The second drive electrode 131a and the second drive electrode 131b are electrically connected via the tip of the drive vibrating arm 130 and the like, although not shown. Similarly, the first drive electrode 132a and the first drive electrode 132b are electrically connected via the tip of the drive vibrating arm 130 and the like, although not shown. The second drive electrodes 131a and 131b and the first drive electrodes 132a and 132b are electrically connected to external connection pads (not shown) via wirings (not shown).

  In the drive vibrating arm 120, the first drive electrode 121a and the first drive electrode 121b are connected to have the same potential, and the second drive electrode 122a and the second drive electrode 122b are connected to have the same potential. ing. In the drive vibrating arm 130, the second drive electrode 131a and the second drive electrode 131b are connected to have the same potential, and the first drive electrode 132a and the first drive electrode 132b have the same potential. It is connected. When alternating voltages having different phases are applied to the drive electrodes having such a configuration, the tuning fork vibrating piece 100 is bent so that the drive vibrating arm 120 and the drive vibrating arm 130 are displaced in the opposite directions along the X-axis direction. The movement is repeated, and bending vibration is performed at a predetermined resonance frequency f.

  The configurations of the first drive electrodes 121a, 121b, 132a, and 132b and the second drive electrodes 122a, 122b, 131a, and 131b described above are not particularly limited as long as they have conductivity and can form a thin film. Specifically, for example, gold (Au), gold alloy, platinum (Pt), aluminum (Al), aluminum alloy, silver (Ag), silver alloy, chromium (Cr), chromium alloy, copper (Cu) , Molybdenum (Mo), niobium (Nb), tungsten (W), iron (Fe), titanium (Ti), cobalt (Co), zinc (Zn), zirconium (Zr) and other metal materials, indium tin oxide (ITO ) Or the like.

  The tuning fork type vibrating piece 100 having the driving vibration arms 120 and 130 having the thickness t as described above is driven to vibrate at a predetermined resonance frequency f. Causes variations in vibration characteristics. As the vibration characteristics, the variation in CI (crystal impedance), which is the drive impedance, has a significant influence on the drive vibration, and thus it is necessary to suppress this variation.

Correspondingly, in the tuning fork type vibrating piece 100, the relationship between the resonance frequency f of the drive vibrating arms 120 and 130 and the thickness t of the drive vibrating arms 120 and 130 is expressed as 0.004> f × t ² > 0. .0008, and more preferably, 0.003> f × t ² > 0.001, so that, for example, even if a variation in outer shape occurs during the production of the tuning fork type vibrating piece 100, the influence is eliminated. can do. That is, it has been found that even with a small tuning fork-type vibrating piece 100, it is possible to reduce the CI value variation or reduce the CI value level due to the variation in the outer shape that occurs during its manufacture.

In a bending vibration piece such as the tuning fork type vibration piece 100, the resonance frequency f _n of the drive vibration arms 120 and 130 and the thickness t of the drive vibration arms 120 and 130 will be described later using Expression (1). Since there is such a relationship, it is possible to determine a good value between the resonance frequency f _n and the thickness t that can satisfy the CI value in the range as described above.

According to the following formula (1), for example, in a bending vibration piece such as a tuning fork type vibration piece, for example, the resonance frequency f _n of out-of-plane vibration is constant, and the thickness t of the drive vibration arm (w in the expression (1)) Increase in the length dimension l of the drive vibrating arm increases. In addition, in the out-of-plane vibration, the thickness direction of the drive vibration arm is the vibration direction, and thus the thickness t that is the dimension in the thickness direction of the drive vibration arm corresponds to the width dimension w of the vibration arm. Thus, when the length l of the driving vibration arm increases, the resonance frequency f _n of the in-plane vibration decreases. In order to stabilize the vibration characteristics of the bending vibration piece, it is necessary to match the in-plane vibration and the out-of-plane vibration to a predetermined resonance frequency, and the resonance frequency f _n of the in-plane vibration is adjusted to a predetermined value (resonance frequency f _n). In order to increase the width dimension w of the driving vibration arm.

In the above state, also the resonance frequency f _n of the in-plane vibration, because thus falls in the same manner as plane vibration described above, in order to keep the resonance frequency f _n constant (increasing the resonant frequency f _n) is driven It is necessary to increase the width dimension w of the vibrating arm. When the length dimension l of the driving vibration arm and the width dimension w of the driving vibration arm are increased so as to keep the resonance frequency f _n of the in-plane vibration constant (resonance frequency f _n is increased), The CI value decreases (decreases).

Similarly to the above, in the out-of-plane vibration, the length dimension l of the drive vibration arm and the drive vibration arm are set so that the resonance frequency f _n of the out-of-plane vibration is kept constant (the resonance frequency f _n is increased). When the thickness t (corresponding to W in equation (1)) is increased, the CI value of the out-of-plane vibration is reduced (decreased).

f _n ∝w / l ² (1)
f _n : Resonant frequency of the vibrating arm, l: Length dimension of the vibrating arm w: Arm width dimension of the vibrating arm (however, the in-plane vibration indicates the arm width in the X-axis direction, and the out-of-plane vibration
(Thickness t in the Z-axis direction corresponds to w)

Further, according to the equation (1), in a bending vibration piece such as a tuning fork type vibration piece, when the thickness t is made constant, the resonance frequency f _n of the out-of-plane vibration is to be increased (to increase). It is necessary to shorten the length l of the drive vibrating arm. In order to stabilize the characteristic by reducing the CI value fluctuation of the bending vibration piece, it is necessary to match the resonance frequencies of the in-plane vibration and the out-of-plane vibration. The resonance frequency f _n of the in-plane vibration also has a length dimension l. Since it becomes shorter, it increases in accordance with the resonance frequency of the out-of-plane vibration described above. Therefore, there is no need to change the width dimension w of the drive vibrating arm. As described above, if the resonance frequency f _n of the out-of-plane vibration is increased while keeping the thickness t constant, the length l of the drive vibration arm is shortened, so that the CI value decreases (decreases). The CI value decreases (decreases) in inverse proportion to the frequency. If the resonance frequency f _n of the out-of-plane vibration is reduced when the thickness t is constant, the length l of the drive vibrating arm is increased, and the CI value increases (increases). . In other words, the CI value is maintained at a low level even when the resonance frequency f _n has to be adjusted by increasing the thickness t so that the resonance frequency f _n varies. Is possible.
As described above, it can be seen that the CI value fluctuates by changing the dimension of the drive vibrating arm in order to adjust the resonance frequency f _n .

FIG. 2 shows a correlation between the thickness t of the drive vibrating arms 120 and 130 in the tuning fork type vibrating piece 100 and the fluctuation of the CI value (drive impedance value). 2 shows the correlation between the CI value fluctuation and f × t ² , FIG. 2A is a graph showing the correlation between the CI value and f × t ^2, and FIG. 2B shows the CI value fluctuation rate and f × is a graph showing the correlation between t ^2. Note that the vertical axis of FIG. 2A indicates the index value of the CI value, where the CI value where f × t ² = 1 is CI value = 1.0.

As shown in FIG. 2A, the resonance frequency f of the drive vibration of the drive vibration arms 120 and 130, the thickness t of the drive vibration arms 120 and 130, and the drive vibration of the drive vibration arms 120 and 130 are as follows. In relation to the CI value, there is a power relation between f × t ² and the CI value. That is, f × t ² and the CI value have a relationship along a curve of CI∝ (f × t ² ) ^−1.27 . From this relationship, it can be seen that the CI value can be lowered by increasing the value of f × t ² .

FIG. 2B shows the change in CI value (CI value fluctuation rate) when the resonance frequency f and the thickness t described above fluctuate. Note that the vertical axis of FIG. 2B represents the CI value variation rate (hereinafter referred to as the CI value variation rate) when the resonance frequency f or the thickness t varies by 1%. As shown in FIG. 2B, the relationship between the CI value variation rate and f × t ² is also a power relationship, and the CI value variation rate is increased by increasing the value of f × t ^2. It can be seen that can be lowered.

According to FIG. 2B, when f × t ² is 0.0008, the CI value variation rate can be 2.0% or less, and when f × t ² is 0.001, CI The value fluctuation rate can be 1.5% or less. The CI value variation rate is preferably as small as possible. However, if it can be suppressed to 2.0% or less, that is, by making f × t ² larger than 0.0008, the vibration characteristics of the drive vibrating arms 120 and 130 can be reduced. The influence on can be minimized. More preferably, by setting f × t ² to 0.001, the CI value variation rate can be reduced to 1.5% or less, and the influence on the vibration characteristics of the drive vibrating arms 120 and 130 is minimized. can do. Thereby, the vibration characteristics of the drive vibrating arms 120 and 130 in the tuning fork type vibrating piece 100 can be stabilized.

Although it is possible to lower the higher the CI value variation rate to be increased to values of f × t ^2, while maintaining a determined resonance frequency f, in order to increase the value of f × t ² is It is necessary to increase the thickness t. In order to increase the thickness t and maintain the determined resonance frequency f, it is necessary to lengthen the drive vibrating arms 120 and 130. Thus, in accordance with increasing the value of f × t ^2, the tuning fork type resonator element 100 size (size) occurs to cause practical problem increases, but the value of f × t ² 0. This can be avoided by making it smaller than 004. In order to make the tuning fork type resonator element 100 smaller, it is preferable to set the value of f × t ² to be smaller than 0.003.

From the above, the relationship between the resonance frequency f and the thickness t of the drive vibrating arms 120 and 130 is set to 0.004> f × t ² > 0.0008, more preferably 0.003> f × t. By setting ² > 0.001, the CI value variation rate can be reduced even if the thickness t of the drive vibrating arms 120 and 130 varies. In other words, the CI value can be lowered even if the outer shape of the tuning fork type vibrating piece 100 varies, and the CI value varies (CI) while maintaining the small tuning fork type vibrating piece 100. (Value fluctuation rate) can be reduced.

  The tuning fork type vibrating piece 100 can be used as a gyro vibrating piece (gyro element) in addition to the configuration used as a vibrating piece. In this case, one of the pair of drive vibration arms 120 and 130 is used as a drive vibration arm, the other drive vibration arm is used as a detection vibration arm, and a predetermined electrode is provided.

(Second Embodiment)
<Gyro element-1>
First, a gyro element as a vibration element according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 3 shows one embodiment of the gyro element, FIG. 3 (a) is a perspective view schematically showing, and FIG. 3 (b) is a plan view schematically showing. 4A and 4B are diagrams for explaining the electrode configuration of the gyro element. FIG. 4A is a cross-sectional view taken along the line CC in FIG. 3B, and FIG. 4B is a cross-sectional view taken along the line DD in FIG. FIG.

  As shown in FIG. 3A, a gyro element 300 according to the third embodiment includes a base 1 formed integrally by processing a base material (material constituting a main part), and a drive as a vibrating arm. The vibration arms 2a and 2b, detection vibration arms 3a and 3b as vibration arms, and adjustment vibration arms 4a and 4b are provided. Furthermore, the 1st connection part 5a extended from the base 1 and the 1st support part 5b connected to the 1st connection part 5a, and the 2nd connection part 6a extended in the opposite direction to the 1st connection part 5a from the base 1 And a second support portion 6b connected to the second connection portion 6a. Furthermore, the first support portion 5b and the second support portion 6b are integrally connected on the drive vibration arms 2a and 2b side to constitute the fixed frame portion 7. The gyro element 300 is fixed to a substrate such as a package (not shown) at a predetermined position of the fixed frame portion 7.

  In the gyro element 300 of the present embodiment, an example in which quartz that is a piezoelectric material is used as a base material will be described. The crystal has an X axis called an electric axis, a Y axis called a mechanical axis, and a Z axis called an optical axis. In the present embodiment, a so-called so-called plate having a predetermined thickness t in the Z-axis direction perpendicular to the plane is cut out along a plane defined by the X-axis and the Y-axis orthogonal to the quartz crystal axis and processed into a flat plate shape. An example in which a quartz Z plate is used as a base material will be described. Here, the predetermined thickness t is appropriately set depending on the oscillation frequency (resonance frequency), the outer size, the workability, and the like. In addition, the flat plate forming the gyro element 300 can tolerate errors in the cut-out angle from the quartz crystal in a certain range for each of the X axis, the Y axis, and the Z axis. For example, it is possible to use what is cut out by rotating in the range of 0 to 2 degrees around the X axis. The same applies to the Y axis and the Z axis.

  The gyro element 300 includes a substantially rectangular base portion 1 located at the center portion, and one end portion (end portion in the (−) Y direction in the figure) 1b of the end portions 1a and 1b in the Y-axis direction of the base portion 1b. A pair of drive vibrating arms 2a, 2b extended along the Y axis so as to be parallel to each other, and parallel to the Y axis from the other end (the end in the (+) Y direction in the figure) 1a of the base 1 And a pair of detection vibrating arms 3a and 3b that are stretched to do so. In this way, the pair of drive vibrating arms 2a and 2b and the pair of detection vibrating arms 3a and 3b are respectively extended in the coaxial direction from both end portions 1a and 1b of the base 1. Due to such a shape, the gyro element 300 according to the present embodiment may be called an H-type gyro element. In the H-type gyro element 300, the drive vibration arms 2a and 2b and the detection vibration arms 3a and 3b are respectively extended from both ends 1a and 1b of the base 1 in the same axial direction. To be separated. The gyro element 300 is characterized in that, by separating the drive system and the detection system in this way, electrostatic coupling between the electrodes of the drive system and the detection system or between the wirings is reduced, and the detection sensitivity is stabilized. In the second embodiment, two drive vibration arms and two detection vibration arms are provided by taking an H-shaped vibration piece as an example, but the number of vibration arms may be one or three or more. . A driving electrode and a detection electrode, which will be described later, may be formed on one vibrating arm.

  When the angular velocity ω is applied around the Y axis in a state where the pair of driving vibration arms 2a and 2b are vibrated in the in-plane direction (+ X axis direction and −X axis direction), the H-type gyro element 300 is driven by the vibration arm. Coriolis force is generated in 2a and 2b, and the drive vibrating arms 2a and 2b bend and vibrate in directions opposite to each other in the out-of-plane direction (+ Z axis direction and −Z axis direction) intersecting the in-plane direction. The detection vibrating arms 3a and 3b resonate with the bending vibration in the out-of-plane direction of the drive vibrating arms 2a and 2b, and similarly bend and vibrate in the out-of-plane direction. At this time, electric charges are generated in the detection electrodes provided on the detection vibrating arms 3a and 3b due to the piezoelectric effect. The gyro element 300 can detect the angular velocity ω applied to the gyro element 300 by detecting this electric charge.

  As shown in FIG. 4, the pair of drive vibrating arms 2 a and 2 b as the vibrating arms extended from the base 1 includes front surfaces 2 c and 2 g, and back surfaces 2 d and 2 h provided on the opposite side of the front surfaces 2 c and 2 g, Side surfaces 2e, 2f, 2k, and 2j connecting the front surfaces 2c and 2g and the back surfaces 2d and 2h are provided. Further, weight portions 52a and 52b, which are wide portions of a substantially rectangular shape, which are wider than the drive vibration arms 2a and 2b (large in the X-axis direction), are provided at the distal ends of the drive vibration arms 2a and 2b. (See FIG. 3). As described above, since the weight portions 52a and 52b are provided in the drive vibration arms 2a and 2b, predetermined drive vibration is achieved while suppressing an increase in the length (dimension in the Y-axis direction) of the drive vibration arms 2a and 2b. Therefore, the gyro element can be downsized. The drive vibration arms 2a and 2b are provided with electrodes for driving the drive vibration arms 2a and 2b. The configuration of the electrodes will be described later.

  The detection vibrating arms 3a and 3b as a pair of vibrating arms extended from the base 1 include the front surfaces 3c and 3g, the back surfaces 3d and 3f provided on the opposite side of the front surfaces 3c and 3g, and the front surfaces 3c and 3g and the back surface. Side surfaces 3h, 3i, 3j, and 3k that connect 3d and 3f are provided. Furthermore, the detection vibrating arms 3a and 3b are provided with weight portions 53a and 53b as wide portions of a substantially rectangular shape that are wider (larger dimensions in the X-axis direction) than the detection vibrating arms 3a and 3b (see FIG. 3). As described above, the detection vibration arms 3a and 3b are also provided with the weight portions 53a and 53b, so that the detection vibration arms 3a and 3b can perform predetermined detection while suppressing an increase in the length (dimension in the Y-axis direction) of the detection vibration arms 3a and 3b. Since vibration can be obtained, the gyro element can be miniaturized. The pair of detection vibrating arms 3a and 3b are provided with recesses 58a and 58b. As shown in FIG. 4, the recesses 58a and 58b in the present embodiment have a configuration that is dug from both sides of the front surface 3c and 3g and the back surface 3d and 3f, but one of the front surface 3c and 3g or the back surface 3d and 3f. The structure dug from the surface may be used.

  Further, in the gyro element 300, as shown in FIG. 3, the detection vibrating arms 3a and 3b are sandwiched inside in parallel with the detection vibrating arms 3a and 3b in a direction intersecting with the crystal X axis (electrical axis) of crystal. As described above, a pair of adjustment vibrating arms 4 a and 4 b extending from the base portion 1 are provided. That is, the adjustment vibrating arms 4a and 4b are extended in the (+) Y direction along the Y axis, and are positioned so as to be sandwiched inside and spaced apart from the detection vibrating arms 3a and 3b by a predetermined distance. Is provided. The adjustment vibrating arms 4a and 4b are sometimes called tuning arms. By providing such adjustment vibrating arms 4a and 4b, the leakage output can be adjusted. In other words, since the drive vibration leaks (propagates), the charge generated by the so-called vibration leak can be canceled by adjusting the charges of the adjustment vibrating arms 4a and 4b, so that the output of the vibration leak is suppressed. Thus, the characteristics of the gyro element 300 can be stabilized.

  The adjustment vibrating arms 4a and 4b are formed to have a shorter overall length than the drive vibrating arms 2a and 2b and the detection vibrating arms 3a and 3b. Thereby, the vibration of the adjustment vibrating arms 4a and 4b for adjusting the leakage output does not hinder the main vibration of the gyro element 300 by the drive vibration arms 2a and 2b and the detection vibration arms 3a and 3b. The vibration characteristics of the gyro element 300 are stabilized, and the gyro element 300 is advantageous in size reduction.

  Furthermore, weight portions 54a and 54b are provided as wide portions of a substantially rectangular shape that are wider than the adjustment vibration arms 4a and 4b (large in the X-axis direction) at the distal ends of the adjustment vibration arms 4a and 4b. It has been. Thus, by providing the weight portions 54a and 54b at the tip ends of the adjustment vibrating arms 4a and 4b, the length of the adjustment vibrating arms 4a and 4b can be shortened.

  The center of the base 1 can be the center of gravity of the gyro element 300. 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 300 can be symmetric with respect to a virtual center line in the Y-axis direction passing through the center of gravity. Accordingly, the outer shape of the gyro element 300 is well balanced, which is preferable because the characteristics of the gyro element 300 are stabilized and the detection sensitivity is improved. Such an outer shape of the gyro element 300 can be formed by etching (wet etching or dry etching) using a photolithography technique. Note that a plurality of gyro elements 300 can be obtained from a single quartz wafer.

  Next, an embodiment of the electrode arrangement of the gyro element 300 will be described with reference to FIG. 4A shows a cross section of the detection vibrating arms 3a and 3b at the CC section shown in FIG. 3B, and FIG. 4B shows the driving vibrating arms 2a and 2b in FIG. 3B. The cross section in the DD section shown is shown.

  First, a description will be given of detection electrodes that are formed on the detection vibrating arms 3a and 3b and detect distortion generated in the quartz crystal that is the base material when the detection vibrating arms 3a and 3b vibrate. As shown in FIG. 4A, the detection vibrating arms 3a and 3b are provided with the recesses 58a and 58b as described above. The recesses 58a and 58b in the present embodiment are provided on both sides of the front surfaces 3c and 3g and the back surfaces 3d and 3f.

  The detection vibrating arm 3a is divided into electrodes provided on the side surface 3h along the extending direction (Y-axis direction) of the detection vibrating arm 3a at the approximate center in the thickness direction (Z-axis direction) of the detection vibrating arm 3a. A first detection electrode 21a on the front surface 3c side and a second detection electrode 22b on the back surface 3d side, which are divided by the portion 3m, are provided. Further, the second detection electrode 22a is provided on the inner side surface of the recess 58a facing the first detection electrode 21a, and the first detection electrode 21b is provided on the inner side surface of the recess 58a facing the second detection electrode 22b. It has been. Further, the surface is divided by the electrode dividing portion 3n provided on the side surface 3i opposite to the side surface 3h at the approximate center in the thickness direction of the detection vibrating arm 3a and provided along the extending direction of the detection vibrating arm 3a. A second detection electrode 22a on the 3c side and a first detection electrode 21b on the back surface 3d side are provided. Furthermore, the first detection electrode 21a is provided on the inner surface of the recess 58a facing the second detection electrode 22a, and the second detection electrode 22b is provided on the inner surface of the recess 58a facing the first detection electrode 21b. It has been.

  The first detection electrode 21a and the first detection electrode 21b are electrically connected via the tip of the detection vibrating arm 3a and the like, although not shown. Although not shown, the second detection electrode 22a and the second detection electrode 22b are electrically connected via the tip of the detection vibrating arm 3a. The first detection electrodes 21a and 21b and the second detection electrodes 22a and 22b are extended to the vicinity of the tip of the detection vibrating arm 3a. The first detection electrodes 21a and 21b and the second detection electrodes 22a and 22b are electrically connected to external connection pads (not shown) through wirings (not shown). The first detection electrodes 21a and 21b and the second detection electrodes 22a and 22b are also electrically connected to an adjustment electrode (not shown) formed on the adjustment vibrating arm 4a (see FIG. 3).

  Similarly, the detection vibrating arm 3b is provided on the side surface 3j along the extending direction (Y-axis direction) of the detection vibrating arm 3b at the approximate center in the thickness direction (Z-axis direction) of the detection vibrating arm 3b. A second detection electrode 31a on the front surface 3g side and a first detection electrode 32b on the back surface 3f side, which are divided by the electrode division unit 3r, are provided. Furthermore, the first detection electrode 32a is provided on the inner side surface of the recess 58a facing the second detection electrode 31a, and the second detection electrode 31b is provided on the inner side surface of the recess 58a facing the first detection electrode 32b. It has been. Further, the surface is divided by the electrode dividing portion 3s provided on the side surface 3k opposite to the side surface 3j in the approximate center in the thickness direction of the detection vibrating arm 3b and provided along the extending direction of the detection vibrating arm 3b. A first detection electrode 32a on the 3g side and a second detection electrode 31b on the back surface 3f side are provided. Furthermore, the second detection electrode 31a is provided on the inner surface of the recess 58b facing the first detection electrode 32a, and the first detection electrode 32b is provided on the inner surface of the recess 58b facing the second detection electrode 31b. It has been.

  The second detection electrode 31a and the second detection electrode 31b are electrically connected via the tip of the detection vibrating arm 3b, etc., although not shown. Although not shown, the first detection electrode 32a and the first detection electrode 32b are electrically connected via the tip of the detection vibrating arm 3b. The second detection electrodes 31a and 31b and the first detection electrodes 32a and 32b extend to the vicinity of the tip of the detection vibrating arm 3b. The second detection electrodes 31a and 31b and the first detection electrodes 32a and 32b are electrically connected to external connection pads (not shown) through wirings (not shown). The second detection electrodes 31a and 31b and the first detection electrodes 32a and 32b are also electrically connected to an adjustment electrode (not shown) formed on the adjustment vibrating arm 4b (see FIG. 3).

  In the detection vibrating arm 3a, the first detection electrode 21a and the first detection electrode 21b are connected to have the same potential, and the second detection electrode 22a and the second detection electrode 22b are connected to have the same potential. ing. Thereby, the distortion produced by the vibration of the detection vibrating arm 3a is detected by detecting the potential difference between the first detection electrodes 21a and 21b and the second detection electrodes 22a and 22b. Similarly, in the detection vibrating arm 3b, the first detection electrode 32a and the first detection electrode 32b are connected to have the same potential, and the second detection electrode 31a and the second detection electrode 31b have the same potential. It is connected to the. Thereby, the distortion caused by the vibration of the detection vibrating arm 3b is detected by detecting the potential difference between the first detection electrodes 32a and 32b and the second detection electrodes 31a and 31b.

  Next, the drive electrodes 11a, 11b, 11c, 12a, 12b, and 12c for driving the drive vibration arms 2a and 2b provided on the drive vibration arms 2a and 2b will be described. As shown in FIG. 4B, the drive electrode 11a is formed on the front surface (one main surface) 2c of the drive vibration arm 2a, the drive electrode 11b is formed on the back surface (the other main surface) 2d, and the weight portion 52a ( (See FIG. 3). Further, a drive electrode 12c is formed on one side 2e and the other side 2f of the drive vibration arm 2a between the weight 52a (see FIG. 3) of the drive vibration arm 2a. Similarly, the drive electrode 12a is provided on the front surface (one main surface) 2g of the drive vibration arm 2b, and the drive electrode 12b is provided on the back surface (the other main surface) 2h until the weight portion 52b (see FIG. 3). Is formed. Further, a drive electrode 11c is formed on one side surface 2j and the other side surface 2k of the drive vibration arm 2b between the weight portion 52b (see FIG. 3) of the drive vibration arm 2b.

  The drive electrodes 11a, 11b, 11c, 12a, 12b, and 12c formed on the drive vibration arms 2a and 2b are arranged so as to have the same potential between the drive electrodes that are arranged to face each other via the drive vibration arms 2a and 2b. The Although not shown, the connection pads formed on the first fixed part to which the drive electrodes 11a, 11b and 11c are connected and the connection formed on the second fixed part to which the drive electrodes 12a, 12b and 12c are connected. By alternately applying a potential difference between the drive electrodes 11a, 11b, and 11c and the drive electrodes 12a, 12b, and 12c through the pads, the so-called tuning fork vibration is excited in the drive vibrating arms 2a and 2b.

  Next, the electrodes provided on the adjustment vibrating arms 4a and 4b will be described. Although not shown, the adjustment vibrating arm 4a has adjustment electrodes having the same potential on the front and back surfaces. Further, other adjustment electrodes having the same potential are formed on both side surfaces of the adjustment vibrating arm 4a. Similarly, adjustment electrodes having the same potential are formed on the front and back surfaces of the adjustment vibrating arm 4b. Further, other adjustment electrodes having the same potential are formed on both side surfaces of the adjustment vibrating arm 4b.

  The configuration of the drive electrodes 11a, 11b, 11c, 12a, 12b, 12c, the first detection electrodes 21a, 21b, 32a, 32b, the second detection electrodes 22a, 22b, 31a, 31b, and the adjustment electrodes described above is as follows. Since it is the same as the electrode configuration described in the first embodiment, the description in this embodiment is omitted.

In the gyro element 300 described above, the relationship between the resonance frequency f of the drive vibrating arms 2a and 2b and the thickness t of the drive vibrating arm is 0.004, as in the tuning fork type vibrating piece 100 of the first embodiment described above. > F × t ² > 0.0008, and more preferably 0.003> f × t ² > 0.001. By doing so, for example, even if variations in the outer shape occur at the time of manufacturing the gyro element 300, the influence can be eliminated. That is, even with the small gyro element 300, it is possible to reduce the CI value variation or reduce the CI value level due to the variation in the outer shape that occurs during the manufacturing process. In order to cause the gyro element 300 to function as a gyro, it is necessary to match the resonance frequencies of the in-plane vibration and the out-of-plane vibration, and increase the resonance frequency f of the in-plane vibration in accordance with the resonance frequency of the out-of-plane vibration ( Therefore, the effect of keeping the value of f × t ² within the above range is produced.

From the above, the relationship between the resonance frequency f of the drive vibrating arms 2a and 2b and the thickness t of the drive vibrating arms 2a and 2b is set to 0.004> f × t ² > 0.0008, more preferably By setting 0.003> f × t ² > 0.001, the CI value variation rate can be reduced even if the thickness t of the drive vibrating arms 2a, 2b varies. In other words, even if variations in the outer shape of the gyro element 300 occur, the CI value of the gyro element 300 can be lowered and the CI value variation (CI value variation rate) can be reduced while maintaining a small size. It becomes possible.

  In the description of the gyro element 300 according to the second embodiment, the pair of detection vibration arms 3a and 3b and the pair of adjustment vibration arms 4a and 4b sandwiching the detection vibration arms 3a and 3b at one end of the base 1 are described. Are used, and a pair of drive vibrating arms 2a and 2b are provided at the other end. However, the present invention is not limited to this configuration. For example, the drive vibration arm and the adjustment vibration arm may be extended in the same direction from the same end of the base.

(Third embodiment)
<Gyro element-2>
Next, a gyro element 400 according to the third embodiment will be described with reference to FIG.
FIG. 5 schematically shows a schematic configuration of the gyro element according to the third embodiment, and is a plan view of the gyro element viewed from the Z-axis direction on the + side. The gyro element 400 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 and driving ground terminals are provided, but are omitted in FIG.

  The gyro element 400 according to the third embodiment is an “out-of-plane detection type” sensor element that detects an angular velocity around the Z-axis, and although not shown, a base material and a plurality of surfaces provided on the surface of the base material are provided. Electrode, wiring, and terminal. The gyro element 400 can be made of a piezoelectric material such as quartz, lithium tantalate, or lithium niobate. Among these, the gyro element 400 is preferably made of quartz. Thereby, the gyro element 400 which can exhibit the outstanding vibration characteristic (frequency characteristic) is obtained.

  Such a gyro element 400 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 connecting the 51 and the second support portion 52 are provided.

  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 in the center, a first detection vibration arm 421 and a second detection vibration arm 422 as vibration arms extending from the base 41 to both sides along the Y-axis direction, The first connecting arm 431 and the second connecting arm 432 that extend from the base 41 to both sides along the X-axis direction, and the vibration that extends from the tip of the first connecting arm 431 to both sides along the Y-axis direction The first drive vibration arm 441 and the second drive vibration arm 442 as arms, and the third drive vibration arm 443 as a vibration arm extending from the tip of the second connection arm 432 to both sides along the Y-axis direction. , And a fourth drive vibrating arm 444. The leading ends of the first and second detection vibrating arms 421 and 422 and the first, second, third, and fourth driving vibrating arms 441, 442, 443, and 444 are each substantially wider than the base end side. Square weight parts (hammer heads) 425, 426, 445, 446, 447, 448 are provided. By providing such weight portions 425, 426, 445, 446, 447, and 448, the angular velocity detection sensitivity of the gyro element 400 is improved.

  The first detection vibrating arm 421 is provided with a bottomed recess 458, and the second detection vibrating arm 422 is provided with a bottomed recess 459. Recesses 458 and 459 are dug from both the front and back surfaces. In addition, the recessed part may be the structure dug from either one of the surface or the back surface.

  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 421 and the first drive vibrating arm 441 to connect the first support portion 51 and the base 41, and the second beam 62 is connected to the first detection vibrating arm 421. The first support part 51 and the base part 41 are connected to each other through the third drive vibration arm 443, and the third beam 63 passes between the second detection vibration arm 422 and the second drive vibration arm 442. 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 vibration arm 422 and the fourth drive vibration arm 444.

  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, the beams 61, 62, 63, and 64 have an action of absorbing the impact, so that detection noise caused by this can be reduced or suppressed.

  The gyro element 400 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 400 causes the drive vibrating arms 441, 442, 443, and 444 to move. Bending vibration is performed in the X-axis direction. At this time, the first and second drive vibrating arms 441 and 442 and the third and fourth drive vibrating arms 443 and 444 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 431 and 432, and the first and second detection vibrating arms 421 and 422 hardly vibrate.

  When an angular velocity ω is applied to the gyro element 400 around the Z axis in this driving vibration state, Coriolis force in the Y axis direction is applied to the driving vibration arms 441, 442, 443, 444 and the connecting arms 431, 432. In response to this vibration in the Y-axis direction, the detected vibration in the X-axis direction is excited. Then, the angular velocity ω is obtained by detecting the distortion of the detection vibrating arms 421 and 422 generated by this vibration as a detection signal.

In the gyro element 400 described above, the relationship between the resonance frequency f and the thickness t of each drive vibrating arm 441, 442, 443, 444 is 0.004 as in the tuning fork type vibrating piece 100 of the first embodiment described above. > F × t ² > 0.0008, and more preferably 0.003> f × t ² > 0.001. By doing so, for example, even if variations in the outer shape occur when the gyro element 400 is manufactured, the influence can be eliminated. That is, even in the small gyro element 400, it is possible to reduce the CI value variation or reduce the CI value level due to the variation in the outer shape that occurs during the manufacturing process.

From the above, the relationship between the resonance frequency f of each drive vibration arm 441, 442, 443, 444 and the thickness t of each drive vibration arm 441, 442, 443, 444 is expressed as 0.004> f × t ² > 0. .0008, and more preferably, 0.003> f × t ² > 0.001, so that the CI value fluctuates even if the thickness t of each drive vibrating arm 441, 442, 443, 444 varies. The rate can be reduced. In other words, even if variations in the outer shape of the gyro element 400 occur, the CI value of the gyro element 400 can be lowered and the CI value variation (CI value variation rate) can be reduced while maintaining a small size. It becomes possible.

  In the gyro element 400 according to the third embodiment, the first detection vibrating arm 421 and the second detection vibrating arm 422 are described as having the recesses 458 and 459. However, the present invention is not limited to this, and the recess 458 is not limited thereto. , 459 may be omitted.

(Manufacturing method of vibration element)
Next, the outline of the manufacturing method of the vibration element will be described with reference to FIG. 6, focusing on the outer shape forming step and the electrode forming step. FIG. 6 is a process flowchart illustrating an outline of a manufacturing process of the resonator element according to the embodiment. In this description, the tuning fork type vibration piece 100 that is the vibration element according to the first embodiment will be described as an example. Accordingly, the same components or symbols as used in the description are the same as those in FIG.

  In the method of manufacturing the tuning fork type vibrating piece 100, a substrate preparation step S102 for forming a quartz Z plate substrate, an outer shape forming step S104 for forming the outer shape of the tuning fork type vibrating piece 100, and an electrode film on the exposed surface of the substrate. An electrode film forming step S106, an exposure step S108 for exposing a resist for dividing the electrode film into a predetermined shape, and an electrode dividing step S110 for forming electrodes.

  First, in the substrate preparation step S102, a so-called quartz Z-plate substrate cut out along a plane defined by the X-axis and the Y-axis orthogonal to the quartz crystal axis is subjected to processing such as polishing, for example. Prepare a quartz substrate.

Next, in the outer shape forming step S104, the quartz substrate prepared in the substrate preparing step S102 is subjected to predetermined masking with a metal film or the like, and then, using a dry etching method using fluorine gas or the like, the tuning fork type vibrating piece 100 is used. The outer shape is formed. At this time, the masking shape is such that the relationship between the driving frequency f and the thickness t in the driving vibrating arms 120 and 130 of the tuning fork type vibrating piece 100 is 0.004> f × t ² > 0.0008, more preferably 0. .003> f × t ² > 0.001 is set. Thus, by forming the outer shape using the dry etching method, the outer shape can be formed with relatively high dimensional accuracy. In addition, since the outer shape forming step by dry etching is provided, a small size that easily satisfies the relationship between the resonance frequency f of the driving vibration arms 120 and 130 and the thickness t of the driving vibration arms 120 and 130 as described above. The tuning fork type vibrating piece 100 can be formed.

  Next, in the electrode film forming step S106, a metal film is formed on the entire exposed surface of the quartz substrate on which the outer shape of the tuning fork type vibrating piece 100 is formed by sputtering or the like. This metal film later becomes each electrode.

  Next, in the exposure step S108, a photoresist layer is formed on the surface of the metal film. Thereafter, an exposure process and a development process for irradiating light to a portion of the photoresist layer corresponding to a portion where no electrode is formed are performed, and the exposed portion of the photoresist layer is removed.

  Next, in the electrode dividing step S110, using the remaining photoresist layer as a mask, the metal film corresponding to the removed photoresist layer is removed by a wet etching method or the like to divide the metal film. By this division, each electrode (electrode pattern) is formed. Then, if the remaining photoresist layer is peeled off, the electrode of the tuning fork type vibrating piece 100 can be formed. The tuning fork type vibrating piece 100 can be formed by the above process.

(Gyro sensor as an electronic device)
Next, a gyro sensor as an electronic device including the gyro element 300 according to the second embodiment will be described with reference to FIG. FIG. 7 is a front sectional view schematically showing a gyro sensor as an example of an electronic device.

  As shown in FIG. 7, the gyro sensor 500 accommodates the gyro element 300 and the semiconductor device 520 as an electronic component in the recess of the package 510, and the opening of the package 510 is sealed with a lid 530. Is kept airtight. The package 510 is formed by sequentially stacking and fixing a first substrate 511 on a flat plate and a frame-shaped second substrate 512, a third substrate 513, and a fourth substrate 514 on the first substrate 511, and a semiconductor device A recess for accommodating 520 and gyro element 300 is formed. The substrates 511, 512, 513, 514 are made of, for example, ceramics.

  In the first substrate 511, a die pad 515 on which the semiconductor device 520 is placed and fixed is provided on an electronic component mounting surface 511a on which the semiconductor device 520 on the concave side is mounted. The semiconductor device 520 is bonded and fixed on the die pad 515 by, for example, a brazing material (die attach material) 540.

  The semiconductor device 520 includes a drive circuit as excitation means for driving and vibrating the gyro element 300 and a detection circuit as detection means for detecting detection vibration generated in the gyro element 300 when an angular velocity is applied. Specifically, the drive circuit included in the semiconductor device 520 includes drive electrodes 11a, 11b, 12c and drive electrodes 11c, 12a formed on the pair of drive vibrating arms 2a, 2b (see FIG. 3) of the gyro element 300, respectively. A drive signal is supplied to 12b (see FIG. 4). Further, the detection circuit included in the semiconductor device 520 includes detection electrodes 21a, 21b, 22a, and 22b and detection electrodes 31a, 31b, 32a, and 32b formed on the pair of detection vibrating arms 3a and 3b of the gyro element 300 (FIG. 4). The detection signal generated in the reference is amplified to generate an amplified signal, and the rotational angular velocity applied to the gyro sensor 500 is detected based on the amplified signal.

  The second substrate 512 is formed in a frame shape having an opening large enough to accommodate the semiconductor device 520 mounted on the die pad 515. The third substrate 513 is formed in a frame shape having an opening wider than the opening of the second substrate 512, and is stacked and fixed on the second substrate 512. A bonding wire BW that is electrically connected to an electrode pad (not shown) of the semiconductor device 520 is formed on the second substrate surface 512a that is formed by laminating the third substrate 513 on the second substrate 512 and appears inside the opening of the third substrate 513. A plurality of IC connection terminals 512b to be connected are formed. An electrode pad (not shown) of the semiconductor device 520 and an IC connection terminal 512b provided in the package 510 are electrically connected using a wire bonding method. That is, a plurality of electrode pads provided in the semiconductor device 520 and the corresponding IC connection terminal 512b of the package 510 are connected by the bonding wire BW. Any one of the IC connection terminals 512b is electrically connected to a plurality of external connection terminals 511c provided on the external bottom surface 511b of the first substrate 511 by an internal wiring (not shown) of the package 510.

  On the third substrate 513, a fourth substrate 514 having an opening wider than the opening of the third substrate 513 is laminated and fixed. A fourth substrate 514 is laminated on the third substrate 513 and is connected to a connection pad (not shown) formed on the gyro element 300 on the third substrate surface 513a that appears inside the opening of the fourth substrate 514. A plurality of gyro element connection terminals 513b are formed. The gyro element connection terminal 513b is electrically connected to one of the IC connection terminals 512b by an internal wiring (not shown) of the package 510. The gyro element 300 is placed on the third substrate surface 513a with the first support portion 5b and the second support portion 6b (see FIG. 3) of the gyro element 300 aligned with the connection pad and the gyro element connection terminal 513b. The adhesive is fixed by a conductive adhesive 550.

  Further, a lid 530 is disposed on the upper surface of the opening of the fourth substrate 514, the opening of the package 510 is sealed, the inside of the package 510 is hermetically sealed, and the gyro sensor 500 is obtained. The lid 530 can be formed using, for example, a metal such as 42 alloy (an alloy containing 42% nickel in iron) or Kovar (an alloy of iron, nickel, and cobalt), ceramics, glass, or the like. For example, when the lid 530 is formed of metal, it is joined to the package 510 by seam welding via a seal ring 560 formed by punching a Kovar alloy or the like into a rectangular ring shape. Since the recessed space formed by the package 510 and the lid 530 serves as a space for the gyro element 300 to operate, it is preferably sealed and sealed in a reduced pressure space or an inert gas atmosphere.

  According to the gyro sensor 500 as an electronic device, since the gyro element 300 with reduced variation in CI value, that is, the gyro element 300 with stable vibration characteristics, is provided, stable sensing characteristics can be exhibited. Further, the package type gyro sensor 500 having the above-described configuration is advantageous for downsizing and thinning and can have high impact resistance.

  As an electronic device to which the vibration element according to the present invention can be applied, in addition to the gyro sensor 500, for example, a vibrator as a timing device in which the vibration element is housed in the package, or the vibration element and vibration in the package There is an oscillator as a timing device that houses a circuit element having at least a function of vibrating the element.

(Electronics)
Next, with reference to FIG. 8, an electronic apparatus including the vibration element according to the above-described embodiment will be described. In the following description, an example in which the gyro element 300 is used as an example of the vibration element will be described. FIG. 8A to FIG. 8C are perspective views illustrating an example of an electronic device including the gyro element 300.

  FIG. 8A shows an example in which the gyro element 300 is applied to a digital video camera 1000 as an electronic apparatus. The digital video camera 1000 includes an image receiving unit 1100, an operation unit 1200, an audio input unit 1300, and a display unit 1400. Such a digital video camera 1000 can be provided with a camera shake correction function in which the gyro element 300 of the above-described embodiment is mounted.

  FIG. 8B shows an example in which the gyro element 300 is applied to a mobile phone 2000 as an electronic device. A cellular phone 2000 shown in FIG. 8B includes a plurality of operation buttons 2100, scroll buttons 2200, and a display unit 2300. By operating the scroll button 2200, the screen displayed on the display unit 2300 is scrolled.

  FIG. 8C shows an example in which the gyro element 300 is applied to a personal digital assistant (PDA) 3000 as an electronic device. A PDA 3000 shown in FIG. 8C includes a plurality of operation buttons 3100, a power switch 3200, and a display unit 3300. When the power switch 3200 is operated, various types of information such as an address book and a schedule book are displayed on the display unit 3300.

  Various functions can be provided by mounting the gyro element 300 of the above-described embodiment on such a cellular phone 2000 or PDA 3000. For example, when a camera function (not shown) is added to the mobile phone 2000 of FIG. 8B, camera shake correction can be performed in the same manner as the digital video camera 1000 described above. In addition, when the mobile phone 2000 of FIG. 8B or the PDA 3000 of FIG. 8C is provided with a global positioning system widely known as GPS (Global Positioning System), the gyro element 300 of the above-described embodiment. , The position and orientation of the mobile phone 2000 and the PDA 3000 can be recognized by GPS.

  Note that the vibration element using the gyro element 300 according to the embodiment of the present invention as an example includes the digital video camera 1000 in FIG. 8A, the mobile phone in FIG. 8B, and the information portable terminal in FIG. 8C. In addition, for example, an ink jet discharge device (for example, an ink jet printer), a laptop personal computer, a television, a video camera, a video tape recorder, a car navigation device, a pager, an electronic notebook (including a communication function), an electronic dictionary , Calculator, electronic game device, word processor, workstation, videophone, TV monitor for crime prevention, electronic binoculars, POS terminal, medical equipment (eg electronic thermometer, sphygmomanometer, blood glucose meter, electrocardiogram measuring device, ultrasonic diagnostic device, electronic internal Endoscope), fish finder, various measuring instruments, instruments (eg, vehicle, navigation) Aircraft, gauges of a ship), can be applied to electronic equipment such as a flight simulator.

(Moving body)
Next, a moving body including the vibration element according to the above-described embodiment will be described. In the following description, an example in which the gyro element 300 is used as an example of the vibration element will be described. FIG. 9 is a perspective view schematically showing an automobile as an example of a moving body. A gyro element 300 is mounted on the automobile 1500. For example, as shown in the figure, an automobile 1500 as a moving body is equipped with an electronic control unit 1510 that incorporates a gyro element 300 and controls tires and the like. The gyro element 300 includes a keyless entry, an immobilizer, a car navigation system, a car air conditioner, an antilock brake system (ABS), an air bag, a tire pressure monitoring system (TPMS), an engine. The present invention can be widely applied to electronic control units (ECUs) such as controls, battery monitors for hybrid vehicles and electric vehicles, and vehicle attitude control systems.

Although the embodiment has been specifically described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment and modification, an example in which quartz is used as a material for forming a vibrating element or a gyro element as a vibrating element has been described, but a piezoelectric material other than quartz can be used. For example, aluminum nitride (AlN), lithium niobate (LiNbO ₃ ), lithium tantalate (LiTaO ₃ ), lead zirconate titanate (PZT), lithium tetraborate (Li ₂ B ₄ O ₇ ), langasite ( Laminated Gauge substrate such as La ₃ Ga ₅ SiO ₁₄ ), laminated piezoelectric substrate constructed by laminating a piezoelectric material such as aluminum nitride or tantalum pentoxide (Ta ₂ O ₅ ) on a glass substrate, or piezoelectric ceramics Can be used. In addition, the vibration element can be formed using a material other than the piezoelectric material. For example, the vibration element can be formed using a silicon semiconductor material or the like. Further, the vibration (drive) method of the vibration element is not limited to piezoelectric drive. In addition to the piezoelectric drive type using a piezoelectric substrate, the configuration of the present invention and its effects can be exerted also in vibration elements such as an electrostatic drive type using electrostatic force and a Lorentz drive type using magnetic force. it can.

  DESCRIPTION OF SYMBOLS 1 ... Base part, 1a, 1b ... End part as one end of a base part, 2a, 2b ... Drive vibration arm as a vibration arm, 2c, 2g ... Front surface, 2d, 2h ... Back surface, 2e, 2f, 2k, 2j ... Side surface, 3a, 3b: Detecting vibrating arm as a vibrating arm, 3c, 3g ... front surface, 3d, 3f ... back surface, 3h, 3i, 3j, 3k ... side surface, 3m, 3n, 3r, 3s ... electrode division part, 4a, 4b ... Adjusting vibrating arms, 5a ... first connecting portion, 5b ... first supporting portion, 6a ... second connecting portion, 6b ... second supporting portion, 7 ... fixed frame portion, 11a, 11b, 11c, 12a, 12b, 12c ... driving electrode, 21a, 21b, 32a, 32b ... first detection electrode, 22a, 22b, 31a, 31b ... second detection electrode, 52a, 52b, 53a, 53b, 54a, 54b ... weight part, 58a, 58b ... concave part , 100 ... tuning-fork type resonator element as a vibration element, 03c, 103g ... front surface, 103d, 103f ... back surface, 103h, 103i, 103j, 103k ... side surface, 110 ... base, 111 ... narrow portion, 112 ... constricted portion, 113 ... wide portion, 120, 130 ... as vibrating arms Drive vibration arm, 121a, 121b, 132a, 132b ... first drive electrode as drive electrode, 122a, 122b, 131a, 131b ... second drive electrode as drive electrode, 300 ... H-type gyro element as vibration element, 400 ... Double T-type gyro element as vibration element, 500 ... Gyro sensor as electronic device, 1000 ... Digital video camera as electronic device, 1500 ... Automobile as mobile body, 2000 ... Mobile phone as electronic device, 3000 ... Electronic A personal digital assistant (PDA) as a device.

Claims (10)

The base,
A drive vibrating arm extending from the base and vibrating at a predetermined resonance frequency f,
The relationship between the resonance frequency f and the thickness t of the drive vibrating arm is
0.004> f × t ² > 0.0008
A vibrating element characterized by the above. The vibration element according to claim 1,
The relationship between the resonance frequency f and the thickness t of the drive vibrating arm is
0.003> f × t ² > 0.001
A vibrating element characterized by the above. The vibration element according to claim 1 or 2,
A vibrating element comprising a detection vibrating arm extending from the base. The vibration element according to any one of claims 1 to 3,
The drive vibrating arm extends from one end of the base,
The vibrating element is characterized in that the detection vibrating arm extends from the other end of the base opposite to the one end. In the vibration element according to any one of claims 1 to 4,
A vibrating element comprising a pair of adjusting vibrating arms extending from the base and provided so that the driving vibrating arm or the detecting vibrating arm is located inside. The vibration element according to any one of claims 1 to 5,
A vibration element characterized in that a wide portion is provided on the other end side opposite to one end connected to the base portion of any one of the drive vibration arm, the detection vibration arm, and the adjustment vibration arm. . The base,
A driving vibration arm having a thickness t that extends from one end of the base and vibrates at a predetermined resonance frequency f.
The relationship between the resonance frequency f and the thickness t of the drive vibrating arm is
Manufacturing of a vibrating element comprising an outer shape forming step of forming an outer peripheral shape of the drive vibrating arm using a dry etching method so that 0.004> f × t ² > 0.0008 Method. The vibration element according to any one of claims 1 to 6,
An electronic component including a drive circuit for exciting at least the drive vibration arm;
An electronic device comprising: a package that houses at least one of the gyro element and the electronic component.   An electronic apparatus comprising the vibration element according to any one of claims 1 to 6.   A moving body comprising the vibration element according to claim 1.

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