Vibrator element including base part, vibrating arm and weight provided to vibrating arm, vibrator device including vibrator element, and method of manufacturing vibrator element

A vibrator element includes at least one vibrating arm with a weight provided thereto. The weight is provided with at least one processing scar. When an axis which overlaps a center in a width direction of the vibrating arm, and which extends along an extending direction of the vibrating arm is a central axis, and an axis which overlaps a centroid of the vibrating arm, and which extends along the extending direction of the vibrating arm is a centroid axis, the processing scar is formed in at least an area at the centroid axis side with respect to the central axis. S1>S2, where an area of the processing scar located at the centroid axis side with respect to the central axis is S1, and an area of the processing scar located at an opposite side to the centroid axis with respect to the central axis is S2.

The present application is based on, and claims priority from JP Application Serial Number 2020-027012, filed Feb. 20, 2020, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a vibrator element, a vibrator device, and a method of manufacturing a vibrator element.

2. Related Art

For example, in JP-A-2009-171553 (Document 1), there is described a method of providing a tip part of a vibrating arm with a metal film, and then irradiating the metal film with a laser beam to thereby remove a part of the metal film as a method of adjusting the frequency of a tuning-fork vibrator element.

The tuning-fork vibrator element described in Document 1 is provided with grooves disposed on an upper surface and a lower surface of the vibrating arm, and electrodes formed in the grooves in order to further enhance the piezoelectric effect. However, since the grooves are formed using wet etching, the shape of the groove becomes asymmetric about the central axis of the vibrating arm due to the etching anisotropy caused by the crystal axes of quartz crystal. When the shape of the groove becomes asymmetric about the central axis of the vibrating arm, the centroid of the vibrating arm is shifted from the central axis, and an unwanted vibration (spurious vibration) is excited due to the shift.

In such a tuning-fork vibrator element, when, for example, a weight is irradiated with the laser beam so as to be symmetric about the central axis, there arises a problem that the shift of the centroid from the central axis increases, and thus, the unwanted vibration increases.

SUMMARY

A vibrator element according to an application example includes abase part, at least one vibrating arm coupled to the base part, and a weight provided to a principal surface of the vibrating arm, wherein the weight is provided with at least one processing scar which is partially removed, and which is recessed in a thickness direction of the vibrating arm, when an axis which overlaps a center in a width direction of the vibrating arm, and which extends along an extending direction of the vibrating arm is defined as a central axis, and an axis which overlaps a centroid of the vibrating arm, and which extends along the extending direction of the vibrating arm is defined as a centroid axis in a plan view of the principal surface, the processing scar is formed in at least an area at the centroid axis side with respect to the central axis, and S1>s2, an area of the processing scar located at the centroid axis side with respect to the central axis is S1, and an area of the processing scar located at an opposite side to the centroid axis with respect to the central axis is S2.

A vibrator device according to an application example includes the vibrator element described above.

A method of manufacturing a vibrator element according to an application example includes the steps of preparing a vibrator element including a base part, a vibrating arm coupled to the base part, and a weight provided to a principal surface of the vibrating arm, and forming at least one processing scar on the weight by irradiating the weight with a laser beam to thin or remove the weight in a thickness direction of the vibrating arm, wherein when an axis which overlaps a center in a width direction of the vibrating arm, and which extends along an extending direction of the vibrating arm is defined as a central axis, and an axis which overlaps a centroid of the vibrating arm, and which extends along the extending direction of the vibrating arm is defined as a centroid axis in a plan view of the principal surface, the processing scar is formed in at least an area at the centroid axis side with respect to the central axis in the forming at least one processing scar, and S1>S2, an area of the processing scar located at the centroid axis side with respect to the central axis is S1, and an area of the processing scar located at an opposite side to the centroid axis with respect to the central axis is S2.

DESCRIPTION OF AN EXEMPLARY EMBODIMENT

A vibrator element, a vibrator device, and a method of manufacturing a vibrator element according to the present disclosure will hereinafter be described in detail based on an embodiment shown in the accompanying drawings.

First Embodiment

FIG.1is a cross-sectional view showing a vibrator device according to a first embodiment of the present disclosure.FIG.2is a plan view of the vibrator device shown inFIG.1.FIG.3is a plan view of a vibrator element provided to the vibrator device shown inFIG.1.FIG.4is a cross-sectional view along the line A-A inFIG.3.FIG.5is a cross-sectional view along the line B-B inFIG.3.FIG.6andFIG.7are each a schematic diagram for explaining an action of the vibrator element shown inFIG.3.FIG.8is a cross-sectional view of a drive arm provided to the vibrator element shown inFIG.3.FIG.9is a cross-sectional view of a detection arm provided to the vibrator element shown inFIG.3.FIG.10is a cross-sectional view showing a shape of a groove in the drive arm.FIG.11is a cross-sectional view showing an unwanted vibration of the drive arm.FIG.12is a cross-sectional view showing an unwanted vibration of the detection arm.FIG.13is a cross-sectional view showing a modified example of a groove in the drive arm.FIG.14is a plan view showing processing scars provided to a weight.FIG.15is a diagram showing a manufacturing process of the vibrator device shown inFIG.1.

It should be noted that in each of the drawings exceptFIG.15throughFIG.17, there are shown an X axis, a Y axis, and a Z axis as three axes perpendicular to each other for the sake of convenience of explanation. Further, a direction parallel to the X axis is also referred to as an X-axis direction, a direction parallel to the Y axis is also referred to as a Y-axis direction, and a direction parallel to the Z axis is also referred to as a Z-axis direction. Further, the arrow side of each of the axes is also referred to as a positive side, and the opposite side is also referred to as a negative side. Further, the positive side in the Z-axis direction is also referred to as an “upper side,” and the negative side thereof is also referred to as a “lower side.” Further, a plan view viewed from the Z-axis direction is also referred to simply as a “plan view.” Further, as described later, the X axis, the Y axis, and the Z axis correspond to the crystal axes of quartz crystal.

The vibrator device1shown inFIG.1is a physical quantity sensor for detecting angular velocity ωz defining the Z axis as the detection axis. As described above, by using the vibrator device1as the physical quantity sensor, it is possible to install the vibrator device1in a wide variety of electronic apparatuses, and thus, the vibrator device1which has a high demand, and is high in convenience is achieved. Such a vibrator device1has a package2, a circuit element3housed in the package2, a support substrate4, and a vibrator element6.

The package2has a base21provided with a recessed part211opening in an upper surface, and a lid22which closes the opening of the recessed part211and is bonded to the upper surface of the base21via a bonding member23. The recessed part211forms an internal space S inside the package2, and the circuit element3, the support substrate4, and the vibrator element6are each housed in the internal space S. For example, the base21can be formed of ceramics such as alumina, and the lid22can be formed of a metal material such as kovar. It should be noted that the constituent materials of the base21and the lid22are not particularly limited.

The internal space S is airtightly sealed, and is set in a reduced-pressure state, and more preferably a state approximate to a vacuum state. Thus, the viscosity resistance reduces and the vibration characteristics of the vibrator element6are improved. It should be noted that the atmosphere in the internal space S is not particularly limited, but can also be, for example, in the atmospheric pressure state or a pressurized state.

Further, the recessed part211is constituted by a plurality of recessed parts, and has a recessed part211a, a recessed part211b, and a recessed part211cwherein the recessed part211aopens in the upper surface of the base21, the recessed part211bopens in a bottom surface of the recessed part211aand is smaller in opening width than the recessed part211a, and the recessed part211copens in a bottom surface of the recessed part211band is smaller in opening width than the recessed part211b. Further, to the bottom surface of the recessed part211a, there is fixed the support substrate4in a state of supporting the vibrator element6, and to a bottom surface of the recessed part211c, there is fixed the circuit element3.

Further, in the internal space S, the vibrator element6, the support substrate4, and the circuit element3are disposed so as to overlap each other in a plan view. In other words, the vibrator element6, the support substrate4, and the circuit element3are arranged side by side along the Z axis. Thus, it is possible to suppress the planar spread towards the X-axis direction and the Y-axis direction of the package2, and thus, it is possible to achieve reduction in size of the vibrator device1. Further, the support substrate4is located between the vibrator element6and the circuit element3, and supports the vibrator element6from the lower side, namely the negative side in the Z axis.

Further, as shown inFIG.1andFIG.2, on the bottom surface of the recessed part211a, there is disposed a plurality of internal terminals241, on the bottom surface of the recessed part211b, there is disposed a plurality of internal terminals242, and on the lower surface of the base21, there is disposed a plurality of external terminals243. The internal terminals241,242and the external terminals243described above are electrically coupled via interconnections not shown formed inside the base21. Further, the internal terminals241are electrically coupled to the vibrator element6via the support substrate4, and the internal terminals242are electrically coupled to the circuit element3via bonding wires BW.

The vibrator element6is an angular velocity sensor element capable of detecting the angular velocity defining the Z axis as the detection axis, that is, the angular velocity ωz around the Z axis. As shown inFIG.3, the vibrator element6has a vibrating substrate7, and electrodes8disposed on a surface of the vibrating substrate7, and weights9.

The vibrating substrate7is formed of a Z-cut quartz crystal substrate. The Z-cut quartz crystal substrate has spread in an X-Y plane defined by the X axis as the electrical axis and the Y axis as the mechanical axis, and has a thickness in a direction along the Z axis as the optical axis, the electrical axis, the mechanical axis, and the optical axis being the crystal axes of quartz crystal. Further, the vibrating substrate7has a base part70, a pair of detection arms71,72, a pair of coupling arms73,74, a pair of drive arms75,76, and a pair of drive arms77,78, wherein the base part70is located in a central portion, the pair of detection arms71,72extend toward both sides in the Y-axis direction from the base part70, the pair of coupling arms73,74extend toward both sides in the X-axis direction from the base part70, the pair of drive arms75,76extend toward the both sides in the Y-axis direction from a tip part of the coupling arm73, and the pair of drive arms77,78extend toward the both sides in the Y-axis direction from a tip part of the coupling arm74. In the present embodiment, the detection arms71,72, and the drive arms75,76,77, and78are each a vibrating arm.

Further, the contour shape of each of the detection arms71,72and the drive arms75,76,77, and78is symmetric about the Y axis in a plan view from the Z-axis direction. It should be noted that term “symmetric” described above means that there is included when the right and left shapes include an error which can occur in manufacturing such as a shape shift when performing wet etching due to the crystal axes of quartz crystal besides when the right and left shapes coincide with each other.

Further, the drive arms75,76,77, and78have wide portions751,761,771, and781larger in width in the X-axis direction than the base end side in tip portions thereof, respectively. Further, the detection arms71,72have wide portions711,721larger in width than the base end side in tip portions thereof, respectively. Thus, it is possible to shorten the detection arms71,72and the drive arms75,76,77, and78, and thus, reduction in size of the vibrator element6can be achieved when being compared at the same frequency. Further, since the length of each of the detection arms71,72and the drive arms75,76,77, and78is shortened, the viscosity resistance when these arms vibrate decreases, and thus, the vibration characteristics are improved. It should be noted that the wide portions711,721,751,761,771, and781are each called a “hammerhead.”

Further, as shown inFIG.4andFIG.5, the drive arms75,76,77, and78are provided with grooves752,762,772, and782each opening in an upper surface as one principal surface, and grooves753,763,773, and783each opening in a lower surface as the other principal surface, respectively. Therefore, the drive arms75,76,77, and78each have a substantially H-shaped cross-sectional shape. Similarly, the detection arms71,72are respectively provided with grooves712,722each opening in an upper surface as one principal surface, and grooves713,723each opening in a lower surface as the other principal surface. Therefore, the detection arms71,72each have a substantially H-shaped cross-sectional shape. By providing the grooves to the respective arms in such a manner, it is possible to reduce the thermoelastic loss, and thus, the vibration characteristics of the vibrator element6are improved.

The electrodes8have drive signal electrodes81, drive constant-potential electrodes82, first detection signal electrodes83, first detection ground electrodes84as detection constant-potential electrodes, second detection signal electrodes85, and second detection ground electrodes86as the detection constant-potential electrodes.

The drive signal electrodes81are disposed on the both side surfaces of each of the drive arms75,76, and the upper surface and the lower surface of each of the drive arms77,78. Meanwhile, the drive constant-potential electrodes82are disposed on the upper surface and the lower surface of each of the drive arms75,76, and the both side surfaces of each of the drive arms77,78. Further, the first detection signal electrodes83are disposed on the upper surface and the lower surface of the detection arm71, and the first detection ground electrodes84are disposed on the both side surfaces of the detection arm71. Meanwhile, the second detection signal electrodes85are disposed on the upper surface and the lower surface of the detection arm72, and the second detection ground electrodes86are disposed on the both side surfaces of the detection arm72.

These electrodes81through86are each laid around to a lower surface of the base part70. Therefore, on the lower surface of the base part70, there are disposed terminals701,702,703,704,705, and706wherein the terminal701is electrically coupled to the drive signal electrode81, the terminal702is electrically coupled to the drive constant-potential electrode82, the terminal703is electrically coupled to the first detection signal electrode83, the terminal704is electrically coupled to the first detection ground electrode84, the terminal705is electrically coupled to the second detection signal electrode85, and the terminal706is electrically coupled to the second detection ground electrode86.

Such a vibrator element6detects the angular velocity ωz in the following manner. First, when applying a drive signal between the drive signal electrode81and the drive constant-potential electrode82, the drive arms75through78flexurally vibrate along an X-Y plane as shown inFIG.6. Hereinafter, this drive mode is referred to as a drive vibration mode. Further, when the angular velocity ωz is applied to the vibrator element6in the state of performing the drive in the drive vibration mode, a detection vibration mode shown inFIG.7is newly excited. In the detection vibration mode, a Coriolis force acts on the drive arms75through78to excite the vibration in a direction represented by the arrows b, and in concert with this vibration, the detection vibration due to the flexural vibration occurs in a direction represented by the arrows a in the detection arms71,72.

Then, a charge generated in the detection arm71due to the detection vibration mode is taken out between the first detection signal electrode83and the first detection ground electrode84as a first detection signal, a charge generated in the detection arm72is taken out between the second detection signal electrode85and the second detection ground electrode86as a second detection signal, and it is possible to detect the angular velocity ωz based on these first and second detection signals.

Further, as shown inFIG.3, the weights9are disposed on the upper surfaces of the wide portions751,761,771, and781of the drive arms75,76,77, and78, and the upper surfaces of the wide portions711,721of the detection arms71,72, respectively. The weights9on the wide portions751,761,771, and781are for adjusting the frequency and the vibration balance in the drive vibration mode, and the weights9on the wide portions711,721are for adjusting the frequency and the vibration balance in the detection vibration mode.

The configuration of the weight9is not particularly limited, but the weight9can be formed of a metal coating obtained by stacking layers of, for example, Au (gold) or Al (aluminum), or an alloy composed primarily of Au (gold) or Al (aluminum). In the present embodiment, the weights9are formed of Au.

Hereinafter, a method of adjusting the frequency and the vibration balance using the weight9will briefly be described. As shown inFIG.8, the weights9on the drive arms75,76,77, and78are irradiated with a laser beam L to remove a part of each of the weights9. Thus, it is possible to reduce the mass of each of the drive arms75,76,77, and78to raise the frequency in the drive vibration mode. Further, by adjusting an elimination amount and an elimination position of the weight9for each of the drive arms75,76,77, and78, it is also possible to adjust the vibration balance in the drive vibration mode. Similarly, as shown inFIG.9, the weights9on the detection arms71,72are irradiated with the laser beam L to remove a part of each of the weights9. Thus, it is possible to reduce the mass of each of the detection arms71,72to raise the frequency in the detection vibration mode. Further, by adjusting an elimination amount and an elimination position of the weight9for each of the detection arms71,72, it is also possible to adjust the vibration balance in the detection vibration mode.

The laser beam L is not particularly limited, but there can be used a pulsed laser beam such as YAG, YVO4, or excimer laser, or a continuous oscillation laser beam such as carbon dioxide laser. It should be noted that in the present embodiment, the pulsed laser beam is used as the laser beam L. Specifically, by continuously irradiating the weights9with the laser beam L converged like a spot, processing of the weights9is performed. By using the pulsed laser beam as the laser beam L in such a manner to thereby change the irradiation time or the irradiation pitch while keeping the intensity of the laser beam L without changing the intensity, it is possible to control the irradiation amount, namely an amount of energy, per unit area of the laser beam L to the weights9. Therefore, the laser beam L is stabilized, and it is possible to accurately perform the present process.

The diameter of a spot SP of the laser beam L is not particularly limited, but is preferably, for example, no larger than 20 μm, and is more preferably no larger than 15 μm. Thus, sufficient microfabrication on the weights9becomes possible.

Further, the laser beam L is not particularly limited, but is preferably a picosecond laser beam. It should be noted that the picosecond laser beam is what is obtained by shortening the pulse width of the laser beam L to the picosecond level. By using the picosecond laser, it is possible to evaporate the weights9with higher peak power compared to, for example, a typical YAG laser. Therefore, processing low in thermal influence becomes possible. Further, it is possible to effectively prevent reattachment of the weight material having been evaporated to a surface of the weight9, and thus, it is possible to effectively prevent dross from adhering to the surface of the weight9.

Further, the pulse width of the laser beam L is not particularly limited, but is preferably shorter than collisional relaxation time as the time for the lattice ion temperature of the constituent material of the weights9to be raised to the melting point. Thus, the advantage described above becomes more conspicuous. In the present embodiment, the weights9are formed of Au, and the collisional relaxation time of Au is about 25 picoseconds. Therefore, the pulse width of the laser beam L is preferably no more than 25 picoseconds, more preferably no more than 20 picoseconds, and further more preferably no more than 10 picoseconds.

By irradiating the weight9with such a laser beam L, a part or the whole of a portion thus irradiated is removed, and thus, processing scars90recessed from the surface are formed. It should be noted that as represented by the solid lines inFIG.8andFIG.9, when a part of the portion irradiated with the laser beam L is removed, the weight9is made to be a thin film in that part, and thus, the processing scar90is formed of the recessed part. Further, as represented by the dotted lines inFIG.8andFIG.9, when the whole of the portion irradiated with the laser beam L is removed, the processing scar90is formed of a through hole. The processing scars90can each be either one thereof. Further, as described above, since the pulsed laser is used as the laser beam L, the processing scar90becomes to have a substantially circular spot-like shape.

The vibrator element6has a feature in an arrangement of the processing scars90. Therefore, hereinafter, the arrangement rule of the processing scars90, in other words, how the processing scars90are arranged at what positions on the weight9, is specifically described. It should be noted that the detection arms71,72, and the drive arms75,76,77, and78are substantially the same in the arrangement rule of the processing scars90. Therefore, hereinafter, the weight9on the drive arm75will be described as a representative, and the description of the weights9on the rest of the detection arms71,72and the drive arms76,77, and78will be omitted.

As described above, the drive arm75is provided with the groove752opening in the upper surface thereof, and the groove753opening in the lower surface thereof. Further, the grooves752,753are each formed by wet etching. Here, quartz crystal as a base material of the vibrating substrate7has etching anisotropy due to the crystal axes. Therefore, as shown inFIG.10, the cross-sectional shape of each of the grooves752,753fails to become a regular rectangular shape, but becomes an awkward polygon. Further, the grooves752,753become to have a shape asymmetric about an axis passing through the center O of the drive arm75along the Z-axis direction.

Therefore, in the cross-sectional view from the Y-axis direction, the centroid G of the drive arm75is shifted toward the negative side in the X-axis direction from the center O of the drive arm75. When such a centroid shift occurs in the drive arm75, a torsional vibration Vd1around the Y axis centering on the centroid G and an antiplane vibration Vd2toward the Z-axis direction of the center O occur in the drive arm75as the unwanted vibrations besides the in-plane vibration as a principal vibration in the drive vibration mode as shown inFIG.11. The same applies to the other drive arms76,77, and78.

Further, when such a centroid shift occurs in the detection arm71, a torsional vibration Vs1around the Y axis centering on the centroid G′ and an antiplane vibration Vs2toward the Z-axis direction of the center O′ occur in the detection arm71as the unwanted vibrations besides the in-plane vibration as a principal vibration in the detection vibration mode as shown inFIG.12. The same applies to the other detection arm72.

When the unwanted vibration other than the principal vibration occurs in the detection arms71,72and the drive arms75,76,77, and78as described above, the vibration balance of the vibrator element6is lost, or a vibration leakage in the vibrator element6increases, and thus, the angular velocity detection characteristics of the vibrator element6deteriorate.

Therefore, in the present embodiment, the arrangement rule of the processing scars90is set so that the shift of the centroid G toward the X-axis direction with respect to the center O decreases to decrease the unwanted vibrations described above compared to before irradiating the weights9with the laser beam L. Hereinafter, an axis which overlaps the center O of the drive arm75in the plan view from the Z-axis direction, and which extends along the extending direction of the drive arm75, namely the Y-axis direction, is defined as a central axis Lo, and an axis which overlaps the centroid G of the drive arm75, and which extends along the extending direction of the drive arm75is defined as a centroid axis Lg. It should be noted that it can be said that the center O is the center in the width direction of the upper surface of the drive arm75, namely the X-axis direction perpendicular to the Y-axis direction as the extending direction, in the plan view from the Z-axis direction.

It should be noted that it is possible to decide the centroid axis Lg based on the centroid G measured using a variety of types of measurement equipment, but it is preferable to uniformly decide the centroid axis Lg in the following manner. In the present embodiment, as shown inFIG.10, an axis extending along the deepest portion752dof the groove752in the plan view from the Z-axis direction is decided as an imaginary axis Ld, and an axis symmetric to the imaginary axis Ld with respect to the central axis Lo is defined as the centroid axis Lg. Thus, it becomes easy to decide the centroid axis Lg, and it becomes easy to form the processing scars90. In particular, since it becomes unnecessary to measure the centroid G for each vibrator element6, it is possible to achieve reduction in manufacturing cycle time of the vibrator element6.

It should be noted that the deepest portion752dis constituted by surfaces each having a width in some cases as shown inFIG.13depending on the width and the depth of the groove752. In this case, it is possible to decide an axis extending along the center in the width direction of the deepest portion752din the plan view from the Z-axis direction as the imaginary axis Ld.

As shown inFIG.14, the processing scars90are formed at least in an area at the centroid axis Lg side with respect to the central axis Lo of the weight9. In other words, the weight9has an area Q1at the negative side in the X-axis direction with respect to the central axis Lo, and an area Q2at the positive side in the X-axis direction with respect to the central axis Lo, and the processing scars90are formed in at least the area Q1. In the present embodiment, the processing scars90are formed in each of the areas Q1, Q2. In the configuration shown inFIG.14, five processing scars90are formed in the area Q1, and one processing scar90is formed in the area Q2. Further, when the area (a sum of the areas of the five processing scars90) of the processing scars90formed in the area Q1is defined as S1, and the area of the processing scar90formed in the area Q2is defined as S2, the relationship of S1>S2is fulfilled. It should be noted that the area described above means the opening area of the processing scar90in the plan view from the Z-axis direction.

Thus, in the decrement of the mass of the weight9due to the formation of the processing scars90, the area Q1becomes larger than the area Q2. In other words, when the decrement of the mass of the weight9in the area Q1is defined as ΔMq1, and the decrement of the mass of the weight9in the area Q2is defined as ΔMq2, the relationship of ΔMq1>ΔMq2is fulfilled. Therefore, by forming the processing scars90, the centroid G is shifted toward the center O compared to before forming the processing scars90, and thus, it is possible to make the centroid G closer to the center O, or preferably make the centroid G coincide with the center O. As a result, by forming the processing scars90, the unwanted vibration of the drive arm75described above decreases, and it is possible to effectively prevent the deterioration of the vibration characteristics of the vibrator element6.

Here, the processing scars90are formed by being irradiated with the laser beam L in the same condition. Therefore, the processing scars90are the same in opening area and depth as each other, and are the same in volume as each other. It should be noted that the term “same” described above means that there is included when there is an error which can occur in the manufacturing process besides when the shapes are the same as each other. Thus, it is possible to fulfill the relationship of ΔMq1>ΔMq2as long as the relationship of (the number of the processing scars90formed in the area Q1)>(the number of the processing scars90formed in the area Q2) is fulfilled. Therefore, it is possible to more easily decide the arrangement of the processing scars90.

It should be noted that it is possible for the shape of at least one of the processing scars90to be different from the shapes of the rest of the processing scars90. In this case, by fulfilling the relationship of (the volume of the processing scars90formed in the area Q1)>(the volume of the processing scars90formed in the area Q2), it is possible to fulfill the relationship of ΔMq1>ΔMq2.

Further, in the plan view from the Z-axis direction, the processing scars90are formed at both sides in the X-axis direction with respect to the centroid axis Lg. In the configuration shown inFIG.14, three processing scars90are formed at the negative side in the X-axis direction of the centroid axis Lg, and three processing scars90are formed at the positive side in the X-axis direction of the centroid axis Lg. Further, a sum of the areas of the three processing scars90formed at the negative side in the X-axis direction of the centroid axis Lg and a sum of the areas of the three processing scars90formed at the positive side in the X-axis direction of the centroid axis Lg are equal to each other. Thus, the processing scars90are disposed at the both sides of the centroid axis Lg in a balanced manner, and thus, it is possible to more surely make the centroid G closer to the center O. Further, the arrangement of the processing scars90becomes easier. It should be noted that the term “equal” described above means there is included when the areas are slightly different from each other due to, for example, an error which can occur in the manufacturing process besides when the areas coincide with each other.

Further, in the plan view from the Z-axis direction, the six processing scars90are arranged side by side in the X-axis direction so as to be symmetric about the centroid axis Lg. Thus, the processing scars90are disposed at the both sides of the centroid axis Lg in a more balanced manner, and thus, it is possible to more surely make the centroid G closer to the center O. Further, the arrangement of the processing scars90becomes easier.

The arrangement rule of the processing scars90is hereinabove described. The number and the arrangement of the processing scars90are not particularly limited as long as the relationship of S1>S2is fulfilled. For example, it is not required to form the processing scar90in the area Q2. Further, the area of the processing scars90formed at the negative side in the X-axis direction of the centroid axis Lg and the area of the processing scars90formed at the positive side in the X-axis direction of the centroid axis Lg can be different from each other. Further, the processing scars90formed at the negative side in the X-axis direction of the centroid axis Lg and the processing scars90formed at the positive side in the X-axis direction of the centroid axis Lg can be asymmetric about the centroid axis Lg. Further, for example, it is preferable to fulfill the relationship of S1>S2in all of the detection arms71,72and the drive arms75,76,77, and78, but this is not a limitation, and it is sufficient to fulfill the relationship of S1>S2in at least one of the detection arms71,72and the drive arms75,76,77, and78.

It should be noted that the six processing scars90are the same in formation position in the Y-axis direction as each other as shown inFIG.14, but this is not a limitation, and it is possible for at least one of the processing scars90to be formed so as to be shifted in the Y-axis direction with respect to the rest of the processing scars90.

Going back toFIG.1, the circuit element3is fixed to the bottom surface of the recessed part211c. The circuit element3includes a drive circuit and a detection circuit for driving the vibrator element6to detect the angular velocity oz applied to the vibrator element6. It should be noted that the circuit element3is not particularly limited, and can include another circuit such as a temperature compensation circuit.

Further, the support substrate4is a substrate used for TAB (Tape Automated Bonding) mounting. As shown inFIG.2, the support substrate4has a base body41shaped like a frame and a plurality of leads42as interconnections provided to the base body41.

The base body41is formed of a film formed of insulating resin such as polyimide. It should be noted that the constituent material of the base body41is not particularly limited, and the base body41can be formed of, for example, insulating resin other than polyimide. Further, the base body41is fixed to the bottom surface of the recessed part211awith bonding members B1, and further, the leads42and the internal terminals241are electrically coupled to each other via the bonding members B1. Further, the base part70of the vibrator element6is fixed to tip portions of the leads42with bonding members B2, and further, the leads42and the terminals701through706are electrically coupled to each other via the bonding members B2, respectively. Thus, the vibrator element6is supported by the base21via the support substrate4, and at the same time, electrically coupled to the circuit element3.

The base body41has a frame-like shape in the plan view from the Z-axis direction, and has an opening part411inside. The six leads42are bonding leads for supporting the vibrator element6, and are wiring patterns constituted by electrically conductive members having electrical conductivity. In the present embodiment, as the electrically conductive members, there is used a metal material such as copper (Cu) or a copper alloy. The six leads42are each fixed to a lower surface of the base body41.

Further, three leads42out of the six leads42are disposed in a part at the positive side in the X-axis direction with respect to the center of the base body41, and the tip portions thereof extend to the inside of the opening part411of the base body41. Meanwhile, three leads42as the rest of the leads42are disposed in a part at the negative side in the X-axis direction with respect to the center of the base body41, and the tip portions thereof extend to the inside of the opening part411of the base body41. A base end portion of each of the leads42is disposed on a lower surface of the base body41, and is electrically coupled to corresponding one of the internal terminals241via the bonding member B1.

Further, the leads42each bend in the middle to be tilted upward, and thus, the tip portions thereof are located above, namely at the positive side in the Z-axis direction of, the base body41. Further, the base part70of the vibrator element6is fixed to the tip portions of the leads42via the bonding members B2. Further, the leads42are electrically coupled to the corresponding terminals701through706via the bonding members B2, respectively.

It should be noted that the bonding members B1, B2are not particularly limited as long as both of the electrical conductivity and the bonding property are provided, and it is possible to use, for example, a variety of metal bumps such as gold bumps, silver bumps, copper bumps, or solder bumps, or an electrically conductive adhesive having an electrically conductive filler such as a silver filler dispersed in a variety of adhesives such as a polyimide type adhesive, an epoxy type adhesive, a silicone type adhesive, or an acrylic adhesive. When using the metal bumps which are in the former group as the bonding members B1, B2, it is possible to suppress generation of a gas from the bonding members B1, B2, and it is possible to effectively prevent a change in environment, in particular rise in pressure, of the internal space S. On the other hand, when using the electrically conductive adhesive which is in the latter group as the bonding members B1, B2, the bonding members B1, B2become relatively soft, and it is possible to absorb or relax the stress in the bonding members B1, B2.

The configuration of the vibrator device1is hereinabove described. Then, a method of manufacturing the vibrator device1, in particular, a method of manufacturing the vibrator element6included therein, will be described. As shown inFIG.15, the method of manufacturing the vibrator device1includes a preparation process of preparing the vibrator element6in a quartz crystal wafer, a first frequency adjustment process of adjusting the frequency of the vibrator element6on the quartz crystal wafer, a mounting process of mounting the vibrator element6on the base21, a second frequency adjustment process of adjusting the frequency of the vibrator element6on the base21, and a sealing process of bonding the lid22to the base21.

Preparation Process

First, by preparing the quartz crystal wafer and patterning the quartz crystal wafer using a photolithography technique and an etching technique, a plurality of vibrating substrates7is formed in the quartz crystal wafer. Then, the electrodes8are formed on the surfaces of the vibrating substrates7using sputtering or the like, and further, the weights9are formed on the upper surfaces of the wide portions711,721,751,761,771, and781of the detection arms71,72and the drive arms75,76,77, and78using evaporation or the like. Thus, the vibrator elements6can be obtained.

First Frequency Adjustment Process

Then, the resonance frequency and the vibration balance of the vibrator element6are adjusted on the quartz crystal wafer. Specifically, the four weights9disposed on the drive arms75,76,77, and78are irradiated with the laser beam L to form the processing scars90based on such an arrangement rule as described above. Thus, it is possible to adjust the frequency and the vibration balance in the drive vibration mode, and at the same time, it is possible to effectively reduce the unwanted vibrations of the drive arms75,76,77, and78in the drive vibration mode. Similarly, the two weights9disposed on the detection arms71,72are irradiated with the laser beam L to form the processing scars90based on such an arrangement rule as described above. Thus, it is possible to adjust the frequency and the vibration balance in the detection vibration mode, and at the same time, it is possible to effectively reduce the unwanted vibrations of the detection arms71,72in the detection vibration mode.

It should be noted that there is no need to provide the processing scars90to all of the weights9, and when there is a weight9which is not required to be provided with the processing scars90, it is possible to omit to form the processing scars90on that weight9. Further, when there is a plurality of weights9which is required to be provided with the processing scars90, it is preferable to form the processing scars90based on the arrangement rule described above with respect to all of the weights9, but this is not a limitation, and it is sufficient to form the processing scars90based on the arrangement rule described above with respect to at least one weight9.

Mounting Process

Then, the vibrator element6is broken off from the quartz crystal wafer, and then the vibrator element6thus broken off is bonded to the base21via the support substrate4. It should be noted that the circuit element3is mounted on the base21in advance.

Second Frequency Adjustment Process

There is a possibility that the resonance frequency and the vibration balance of the vibrator element6vary from the resonance frequency and the vibration balance on the quartz crystal wafer by fixing the vibrator element6to the base21in the mounting process described above. Therefore, in the present process, the processing scars90are formed to at least one weight9to adjust the resonance frequency and the vibration balance in the drive vibration mode and the resonance frequency and the vibration balance in the detection vibration mode in substantially the same manner as in the first frequency adjustment process described above. It should be noted that the present process can be omitted when not required.

Sealing Process

Then, in the vacuum state, for example, the lid22is seam welded to an upper surface of the base21via the bonding member23made of a seam ring. Thus, the internal space S is airtightly sealed, and the vibrator device1is obtained.

The method of manufacturing the vibrator device1is described hereinabove, but the method of manufacturing the vibrator device1is not particularly limited providing the method follows the arrangement rule of the processing scars. For example, when performing the second frequency adjustment process, the first frequency adjustment process can be omitted. Further, when performing the first frequency adjustment process, the second frequency adjustment process can be omitted. Further, either one of the first frequency adjustment process and the second frequency adjustment process can be performed using a different frequency adjustment method from the method described above.

The vibrator device1and the method of manufacturing the vibrator device1are hereinabove described. The vibrator element6included in such a vibrator device1has the base part70, the detection arms71,72and the drive arms75,76,77, and78as the vibrating arms coupled to the base part70, and the weights9disposed on the upper surfaces as the principal surfaces of the detection arms71,72and the drive arms75,76,77, and78. Further, the weights9are provided with the processing scars90which are partially removed and are recessed in the thickness direction of the detection arms71,72and the drive arms75,76,77, and78, namely the Z-axis direction, respectively. When the axis which overlaps the center O in the width direction of the drive arm75, and which extends along the Y-axis direction as the extending direction of the drive arm75is defined as the central axis Lo, and the axis which overlaps the centroid G of the drive arm75, and which extends along the Y-axis direction as the extending direction of the drive arm75is defined as the centroid axis Lg in the plan view of the upper surface, the processing scars90are formed in at least the area Q1located at the centroid axis Lg side with respect to the central axis Lo. Further, when the area of the processing scars90located at the centroid axis Lg side of the central axis Lo is defined as S1and the area of the processing scars90located at the opposite side to the centroid axis Lg of the central axis Lo is defined as S2, the relationship of S1>S2is fulfilled. It should be noted that this relationship similarly applies to the detection arms71,72and the drive arms76,77, and78.

Thus, in the decrement of the mass of the weight9due to the formation of the processing scars90, the area Q1becomes larger than the area Q2. In other words, when the decrement of the mass of the weight9in the area Q1is defined as ΔMq1, and the decrement of the mass of the weight9in the area Q2is defined as ΔMq2, the relationship of ΔMq1>ΔMq2is fulfilled. Therefore, by forming the processing scars90, the centroid G is shifted toward the center O compared to before forming the processing scars90, and thus, it is possible to make the centroid G closer to the center O, or preferably make the centroid G coincide with the center O. As a result, by forming the processing scars90, the unwanted vibration decreases, and it is possible to effectively prevent the deterioration of the vibration characteristics of the vibrator element6.

Further, as described above, the processing scars90are formed at both sides in the X-axis direction as the width direction with respect to the centroid axis Lg. Further, the area of the processing scars90formed at one side in the X-axis direction with respect to the centroid axis Lg and the area of the processing scars90formed at the other side in the X-axis direction with respect to the centroid axis Lg are equal to each other. Thus, the processing scars90are disposed at the both sides of the centroid axis Lg in a balanced manner, and thus, it is possible to more surely make the centroid G closer to the center O. Further, the arrangement of the processing scars90becomes easier.

Further, as described above, the processing scars90are disposed symmetrically about the centroid axis Lg. Thus, the processing scars90are disposed at the both sides of the centroid axis Lg in a more balanced manner, and thus, it is possible to more surely make the centroid G closer to the center O. Further, the arrangement of the processing scars90becomes easier.

Further, as described above, the processing scars90are each shaped like a spot. Thus, it becomes easy to process the weights9.

Further, as described above, the vibrator element6has the pair of detection arms71,72extending toward the both sides in the Y-axis direction as a first direction from the base part70, the pair of coupling arms73,74extending toward the both sides in the X-axis direction as a second direction perpendicular to the Y-axis direction from the base part70, the pair of drive arms75,76as the vibrating arms extending toward the both sides in the Y-axis direction from one coupling arm73, and the pair of drive arms77,78as the vibrating arms extending toward the both sides in the Y-axis direction from the other coupling arm74. Thus, it is possible to effectively adjust the frequency and the vibration balance in the drive vibration mode of the vibrator element6.

Further, as described above, the vibrator element6has the pair of detection arms71,72as the vibrating arms extending toward the both sides in the Y-axis direction as the first direction from the base part70, the pair of coupling arms73,74extending toward the both sides in the X-axis direction as the second direction perpendicular to the Y-axis direction from the base part70, the pair of drive arms75,76extending toward the both sides in the Y-axis direction from one coupling arm73, and the pair of drive arms77,78extending toward the both sides in the Y-axis direction from the other coupling arm74. Thus, it is possible to effectively adjust the frequency and the vibration balance in the detection vibration mode of the vibrator element6.

Further, as described above, the vibrator device1has the vibrator element6. Thus, it is possible for the vibrator device1to acquire the advantages of the vibrator element6, and exert the high reliability.

Further, as described above, the method of manufacturing the vibrator element6includes the step of preparing the vibrator element6having the base part70, the detection arms71,72and the drive arms75,76,77, and78as the vibrating arms coupled to the base part70, and the weights9disposed on the upper surfaces as the principal surfaces of the detection arms71,72and the drive arms75,76,77, and78, the step of forming the processing scars90on the weights9by irradiating the weights9with the laser beam L to thin or remove the weights9in the thickness direction of the detection arms71,72and the drive arms75,76,77, and78. Further, when the axis which overlaps the center O in the width direction of the drive arm75, and which extends along the Y-axis direction as the extending direction of the drive arm75is defined as the central axis Lo, and the axis which overlaps the centroid G of the drive arm75, and which extends along the Y-axis direction as the extending direction of the drive arm75is defined as the centroid axis Lg in the plan view of the upper surface, the processing scars90are formed in at least the area Q1located at the centroid axis Lg side with respect to the central axis Lo in the step of forming the processing scars90. Further, when the area of the processing scars90located at the centroid axis Lg side of the central axis Lo is defined as S1and the area of the processing scars90located at the opposite side to the centroid axis Lg of the central axis Lo is defined as S2, the relationship of S1>S2is fulfilled.

Thus, in the decrement of the mass of the weight9due to the formation of the processing scars90, the area Q1becomes larger than the area Q2. In other words, when the decrement of the mass of the weight9in the area Q1is defined as ΔMq1, and the decrement of the mass of the weight9in the area Q2is defined as ΔMq2, the relationship of ΔMq1>ΔMq2is fulfilled. Therefore, by forming the processing scars90, the centroid G is shifted toward the center O compared to before forming the processing scars90, and thus, it is possible to make the centroid G closer to the center O, or preferably make the centroid G coincide with the center O. As a result, by forming the processing scars90, the unwanted vibration decreases, and it is possible to effectively prevent the deterioration of the vibration characteristics of the vibrator element6.

Although the vibrator element, the vibrator device, and the method of manufacturing the vibrator element according to the present disclosure are hereinabove described based on the illustrated embodiment, the present disclosure is not limited thereto, but the configuration of each of the constituents can be replaced with one having an arbitrary configuration with an equivalent function. Further, the present disclosure can also be added with any other constituents. Further, it is also possible to arbitrarily combine any of the embodiments with each other.