JP2016200520A - Angular velocity sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric angular velocity sensor improved in drive efficiency.SOLUTION: The piezoelectric angular velocity sensor includes: a base plate; a first electrode formed on the base plate; a first piezoelectric layer formed over the first electrode; a second electrode formed on the first piezoelectric layer; a second piezoelectric layer formed over the second electrode; a third electrode formed on the second piezoelectric layer; and a circuit board. The first electrode, the second electrode and the third electrode are electrically connected to the circuit board. An electric signal is input to the first electrode and the third electrode from the circuit board, and the second electrode is connected to a ground potential.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an angular velocity sensor used for an electronic device or the like.

  Conventionally, as an angular velocity sensor using a piezoelectric thin film, for example, there is an angular velocity sensor described in Patent Document 1. Here, in Patent Document 1, the angular velocity is detected by a sensor in which an electrode and a piezoelectric thin film are stacked on a silicon substrate.

JP 2006-23186 A

  In the conventional angular velocity sensor, driving vibration is generated in the silicon substrate by applying a voltage to the piezoelectric thin film. However, when a material having a low piezoelectric constant is used as the material for the piezoelectric thin film, a sufficient drive amplitude cannot be obtained. As a result, there is a problem that the sensitivity of the angular velocity sensor is lowered.

  Accordingly, the present invention provides a substrate, a first electrode provided on the substrate, a first piezoelectric layer provided on the first electrode, and a first electrode provided on the first piezoelectric layer. 2 electrodes, a second piezoelectric layer provided on the second electrode, a third electrode provided on the second piezoelectric layer, and a circuit board. The first, second, and third electrodes are electrically connected to the circuit board, and the first and third electrodes receive an electric signal from the circuit board, and the second electrode Are connected to the ground potential.

  According to the present invention, an angular velocity sensor with improved driving efficiency can be provided.

The perspective view of the angular velocity sensor of Embodiment 1 Top view of the vibrator provided in the same angular velocity sensor Sectional drawing in the AA line of FIG. The figure which shows another example of the cross section in AA of FIG. The figure which shows another example of the cross section in AA of FIG. (A) The figure which expanded a part of vibrator | oscillator of FIG. 2, (b) Sectional drawing in the BB line of (a) Another sectional view taken along line BB in FIG. An enlarged top view of a part of FIG. Still another cross-sectional view taken along line BB in FIG. Still another cross-sectional view taken along line BB in FIG. (A) Still another cross-sectional view taken along line BB in FIG. 6 (a), (b) a diagram representing the back surface of the substrate, and (c) a diagram representing a mounting position of the substrate Sectional drawing which shows another structure of an electrode part Diagram showing the manufacturing process of the vibrator Another diagram showing the manufacturing process of the vibrator Sectional drawing which shows another structure of the electrode part 35

  Hereinafter, the angular velocity sensor of the present embodiment will be described with reference to the drawings.

  FIG. 1 is a perspective view of an angular velocity sensor according to the present embodiment.

  FIG. 2 is a top view of the vibrator 21 provided in the angular velocity sensor of the present embodiment.

  The angular velocity sensor includes a vibrator 21, a circuit board 22 connected to the vibrator 21, and a case 23 that houses the vibrator 21 and the circuit board 22.

  The vibrator 21 has a shape in which a pair of arm portions 25 are connected to the base portion 24. The arm portion 25 is provided with a drive electrode portion 26, a sensing electrode portion 27, a monitor electrode portion 28, and an electrode portion 35 that electrically or physically connects the vibrator 21 to an external substrate. The shape of the vibrator is not limited to the shape in which the pair of arm portions 25 are connected to the base portion 24. For example, various shapes such as a king-shaped vibrator, an H-shaped vibrator, or a vibrator having three or four arms may be employed.

  3 is a cross-sectional view taken along line AA in FIG.

  The drive electrode portion 26 is a portion to which a drive signal for vibrating the vibrator 21 is input from the circuit board 22.

  The monitor electrode unit 28 is a part that detects the vibration state of the vibrator 21 and outputs a detection signal.

  The sensing electrode unit 27 is a part that outputs an angular velocity signal generated due to the angular velocity applied to the vibrator 21.

  The drive electrode unit 26, the sensing electrode unit 27, and the monitor electrode unit 28 include a first electrode 29 provided on the silicon substrate 33, and a piezoelectric layer 30 a made of a piezoelectric material provided on the first electrode 29. A second electrode 31 provided on the piezoelectric layer 30a, a piezoelectric layer 30b provided on the second electrode 31, and a third electrode 32 provided on the piezoelectric layer 30b. Yes. The material of the substrate 33 is not limited to silicon. For example, stainless steel may be used.

  The second electrode 31 is electrically connected to the ground potential. Here, the ground potential means a potential serving as a reference for the drive potential and the sensing potential. For example, when the ground potential, that is, the reference potential is 0V and the driving voltage is 5V, the drive potential of the drive electrode section 26 is in the range of −2.5 to + V2.5V.

  In addition, the third electrode 32 and the first electrode 29 receive an electric signal from the circuit board 22. Thereby, the vibrator 21 vibrates.

  Each arm in the vibrator 21 is formed by a pair of drive electrode portions 26 and a single sensing electrode portion 27, and the pair of drive electrode portions 26 is configured to sandwich the sensing electrode portion 27. The When a voltage is applied to the drive electrode portion 26, an electric field is generated in the piezoelectric layer of the drive electrode portion 26. As a result, the film expands and contracts due to the inverse piezoelectric effect.

  Therefore, when a voltage having a phase difference of 180 ° is applied to each drive electrode portion 26 in one arm, the piezoelectric layer on one side expands and contracts, and the piezoelectric layer on the other side contracts. As a result, the arm is displaced along the contracted side. In the pair of arms constituting the vibrator, the arrangement of the electrodes is reversed between the arms, so that when the voltage of a constant frequency is applied, the vibrator arm can be opened and closed. it can.

  When the piezoelectric layer is the same, this expansion and contraction is determined by the direction of the electric field with respect to the direction of the polarization axis of the piezoelectric layer, and the magnitude of the expansion and contraction is determined by the magnitude of the electric field applied to the piezoelectric layer.

  The drive electrode portion 26 has a structure in which two piezoelectric layers are stacked. In addition, the stacked piezoelectric layers were configured so that the relationship between the direction of the polarization axis and the direction of the electric field was the same in both layers. That is, the polarization direction of the first piezoelectric layer 30a and the polarization direction of the second piezoelectric layer 30b are different from each other. For this reason, the electric field strength applied to each film makes the film thickness of each piezoelectric layer thinner compared to the case where the electrode is composed of a single piezoelectric layer having the same film thickness as the sum of the film thickness of each layer. Since it increases in inverse proportion to the minute, the drive amplitude can be improved as compared with the case where the electrode is composed of a single piezoelectric layer having the same thickness as the sum of the thicknesses of the respective layers.

  The width and thickness of the first electrode 29 and the third electrode 32 are equal to each other. As a result, the resistances of the upper and lower electrodes can be made uniform, so that driving and detection can be stabilized.

  Further, the end portions of the first electrode 29 and the third electrode 32 are aligned with each other in the cross section of the vibrator 21. In another expression, the first electrode 29 and the third electrode 32 overlap each other when the vibrator 21 is viewed from above. Thereby, a uniform electric field can be generated.

  The thicknesses of the piezoelectric layer 30a and the piezoelectric layer 30b are equal to each other. Thereby, substantially equal electric fields are generated in the piezoelectric layer 30a and the piezoelectric layer 30b. As a result, the piezoelectric layer 30a and the piezoelectric layer 30b expand and contract approximately equally. Thereby, the operation of the vibrator 21 is stabilized. The piezoelectric layer 30a and the piezoelectric layer 30b are both made of a piezoelectric material made of lead zirconate titanate. In another expression, the piezoelectric layer 30a and the piezoelectric layer 30b are made of the same material. However, the material of the piezoelectric layer 30a and the piezoelectric layer 30b is not limited to lead zirconate titanate. The piezoelectric layer 30a and the piezoelectric layer 30b may be made of different materials.

In particular, the structure of the vibrator 21 is preferably used when a piezoelectric material that does not have a large drive amplitude, that is, a piezoelectric material with low piezoelectric characteristics is used. For example, in the case of an NBT-BT (((Na, Bi) _1-x Ba _x ) TiO ₃ ) film whose piezoelectric performance is lower than 70% compared to lead zirconate titanate, Not enough vibration characteristics. However, by using the structure of the vibrator 21, the vibration characteristics of the vibrator using the NBT-BT film as a piezoelectric material can be improved.

  In addition, between the piezoelectric layer 30a and the first electrode 29, or between the piezoelectric layer 30a and the second electrode 31, for example, a metal film for improving adhesion, metal diffusion is suppressed. A metal film and a film for preventing metal oxidation may be provided as necessary. This possibility of deformation extends to all the electrodes of the present embodiment.

  FIG. 4 is a diagram illustrating another example of a cross section taken along line AA of FIG.

  In the case of FIG. 4, the drive electrode portion 26 and the sensing electrode portion 27 include a first electrode 29 provided on a silicon substrate 33 and a piezoelectric layer 30 a made of a piezoelectric material provided on the first electrode 29. A second electrode 31 provided on the piezoelectric layer 30a, a piezoelectric layer 30b provided on the second electrode 31, and a third electrode 32 provided on the piezoelectric layer 30b. ing.

  The drive electrode portion 26 and the sensing electrode portion 27 are separated from each other. Thereby, the electric field leakage between the drive electrode part 26 and the sensing electrode part 27 can be suppressed.

  The second electrode 31 is electrically connected to the ground potential.

  In addition, the third electrode 32 and the first electrode 29 receive an electric signal from the circuit board 22. Thereby, the vibrator 21 vibrates.

  FIG. 5 is a diagram illustrating another example of a cross section taken along line AA in FIG. 2.

  In the case of FIG. 5, the drive electrode portion 26 and the sensing electrode portion 27 include a first electrode 29 provided on the silicon substrate 33 and a piezoelectric layer 30 a made of a piezoelectric material provided on the first electrode 29. A second electrode 31 provided on the piezoelectric layer 30a, a piezoelectric layer 30b provided on the second electrode 31, and a third electrode 32 provided on the piezoelectric layer 30b. ing.

  In addition, the piezoelectric layer 30 a, the second electrode 31, the piezoelectric layer 30 b, and the third electrode 32 are separated from each other between the drive electrode unit 26 and the sensing electrode unit 27. On the other hand, the drive electrode unit 26 and the sensing electrode unit 27 share the first electrode 29.

  Both the first electrode 29 and the third electrode 32 are electrically connected to the ground potential.

  The second electrode 31 receives an electric signal from the circuit board 22. Thereby, the vibrator 21 vibrates.

  6A is an enlarged view of a part of the vibrator 21 in FIG. 2, and FIG. 6B is a cross-sectional view taken along line BB in FIG. 6A. In another expression, FIG. 6B is a cross-sectional view of the electrode portion 35 that is electrically connected to the sensing electrode portion 27. An electrode unit is also connected to the drive electrode unit 26 and the monitor electrode unit 28. Since these structures are the same as the above-mentioned structure, description is abbreviate | omitted.

  The electrode portion 35 includes a first electrode 29 provided on the silicon substrate 33, a piezoelectric layer 30a made of a piezoelectric material provided on the first electrode 29, and a second electrode provided on the piezoelectric layer 30a. Electrode 31, a piezoelectric layer 30b provided on the second electrode 31, and a third electrode 32 provided on the piezoelectric layer 30b.

  The electrode part 35 is electrically connected to the first electrode 29, the first electrode part 35 a, the electrode part 35 is electrically connected to the second electrode 31, the second electrode part 35 b, and the third electrode 32. And a third electrode portion 35c for electrical connection.

  In the first electrode portion 35a, at least a part of the piezoelectric layer 30b is exposed when the vibrator 21 is viewed from above. In other words, the end of the piezoelectric layer 30 b extends from the end of the third electrode 32 in the cross section of the vibrator 21.

  In the first electrode portion 35a, the end portion of the second electrode 31 is set back from the end portion of the piezoelectric layer 30b.

  In the first electrode portion 35a, the end portion of the piezoelectric layer 30a substantially coincides with the end portion of the piezoelectric layer 30b.

  In the first electrode portion 35a, at least a part of the first electrode 29 is exposed when the vibrator 21 is viewed from above.

  As a result, at least a part of the upper surface of the first electrode 29 is exposed, so that electrical connection is easy. At the same time, since the end portion of the second electrode 31 and the end portion of the third electrode 32 are provided so as to recede, defects such as a short circuit can be suppressed.

  In the second electrode portion 35b, at least a part of the piezoelectric layer 30b is exposed when the vibrator 21 is viewed from above. In other words, the end of the piezoelectric layer 30 b extends from the end of the third electrode 32 in the cross section of the vibrator 21.

  In the second electrode portion 35b, at least a part of the second electrode 31 is exposed when the vibrator 21 is viewed from above.

  As a result, at least a part of the upper surface of the second electrode 31 is exposed, and electrical connection is easy. At the same time, since the end of the third electrode 32 is provided so as to recede, defects such as a short circuit can be suppressed.

  The third electrode portion 35c is provided on the first electrode 29 provided on the silicon substrate 33, the piezoelectric layer 30a made of a piezoelectric material provided on the first electrode 29, and the piezoelectric layer 30a. The second electrode 31, the piezoelectric layer 30b provided on the second electrode 31, and the third electrode 32 provided on the piezoelectric layer 30b are provided.

  The first electrode portion 35a, the second electrode portion 35b, and the third electrode portion 35c are separated from each other.

  Moreover, it is preferable to provide the 1st electrode part 35a and the 2nd electrode part 35b in the position which does not mutually adjoin. In other words, it is preferable to provide the third electrode part 35c between the first electrode part 35a and the second electrode part 35b. Thereby, it can suppress that a defect generate | occur | produces in the 2nd electrode part 35b. This point will be described in detail. In the step of side etching for the second electrode 31 performed when forming the first electrode portion 35a, the side etching may proceed to the second electrode 31 of the adjacent electrode portion. In such a case, if the adjacent electrode portion is the second electrode portion 35b, the second electrode 31 used for solder or wire bonding disappears by side etching, and solder or wire bonding mounting cannot be achieved. is there. Therefore, by providing the first electrode portion 35a and the second electrode portion 35b at positions that do not adjoin each other, it is possible to suppress the occurrence of defects in the second electrode portion.

The second electrode portion 35b is connected to the ground potential. The first electrode portion 35 a and the third electrode portion 35 c are electrically connected to the circuit board 22.
FIG. 7 is another cross-sectional view taken along the line BB in FIG. FIG. 7 shows a state in which a metal wire is connected to each of the first electrode portion 35a, the second electrode portion 35b, and the third electrode portion 35c.

  In the 1st electrode part 35a, since the edge part of the 2nd electrode 31 and the edge part of the 3rd electrode 32 are set back, the unintended contact with a metal wire can be suppressed.

  In the first electrode portion 35 a, a metal wire is connected to the upper surface of the first electrode 29.

  In the 2nd electrode part 35b, since the edge part of the 3rd electrode 32 is retracted and provided, the unintended contact with a metal wire can be suppressed.

  In the second electrode part 35 b, a metal wire is connected to the upper surface of the second electrode 31.

  In the third electrode portion 35 c, a metal wire is connected to the upper surface of the third electrode 32.

  FIG. 8 is an enlarged top view of the broken line portion of FIG. In other words, it is a top view of the second electrode portion 35b.

  The upper surface of the third electrode 32 is exposed. The shape is a frame shape in which the inner periphery and the outer periphery are square.

  A part of the upper surface of the second piezoelectric layer 30b is exposed. The shape is a frame shape whose inner periphery and outer periphery are rectangular.

  A part of the upper surface of the second electrode 31 is exposed. The shape is a square shape. With this configuration, a region 31 a for soldering or wire bonding can be provided on the upper surface of the second electrode 31.

  The second piezoelectric layer is exposed between the third electrode 32 and the second electrode 31 in a top view. As an example, the width at which the second piezoelectric layer 30b is exposed between the third electrode 32 and the second electrode 31 is 10 μm.

  As an example, the closest width from the second piezoelectric layer 30b to the solder or wire bonding region 31a is 10 μm.

  FIG. 9 is still another cross-sectional view taken along line BB in FIG. FIG. 9 shows a state in which a metal wire is connected to each of the first electrode portion 35a, the second electrode portion 35b, and the third electrode portion 35c.

  In the case of FIG. 9, the first electrode 29 is shared among the first electrode portion 35a, the second electrode portion 35b, and the third electrode portion 35c. Thereby, since the electrical connection of the first electrode 29 can be achieved simultaneously for a plurality of electrode portions, the number of electrodes can be reduced.

  In the first electrode portion 35a, the side surface of the second piezoelectric layer 30b is tapered. In particular, the opening diameter increases as the distance from the substrate 33 increases. Such a structure of the piezoelectric layer 30b can also be applied to the structure of FIG.

  FIG. 10 is still another cross-sectional view taken along line BB in FIG. FIG. 10 shows a state where each of the first electrode portion 35a, the second electrode portion 35b, and the third electrode portion 35c is connected by a solder ball.

  In the case of FIG. 10, electrical connection with each electrode part is achieved using solder. In particular, in the first electrode portion 35a, since the second electrode 31 is retracted with respect to the piezoelectric layer 30a and the piezoelectric layer 30b, the solder and the second electrode 31 are not intended even when the solder is deformed. It is possible to suppress contact.

  Fig.11 (a) is another sectional drawing in CC line of Fig.6 (a). FIG. 11B is a top view of the substrate 40 as viewed from the surface on which the metal films 51 and 52 are provided, and FIG. 11C is a schematic diagram showing the mounting position of the substrate 40.

  In the case of FIG. 11, a substrate 40 is further provided. The substrate 40 is connected to the plurality of third electrodes 32.

  The substrate 40 includes a metal film 51 having a thickness W5 and a metal film 52 having a thickness W6. Here, W6> W5.

  The metal film 51 and the metal film 52 are electrically connected to each other. The metal film 52 is connected to the plurality of third electrodes.

  The material of the metal film 51 is, for example, tungsten. The material of the metal film 52 is, for example, gold.

  Further, the substrate 40 may be separate from the case 23 or may be a part of the case 23.

The board | substrate 40 is connected to the broken-line part shown in FIG.11 (c). As a result, the plurality of third electrodes 32 can be made equipotential, and the electrical signals of the third electrodes 32 are extracted at once, or the electrical signals are sent to the plurality of third electrodes 32 at once. be able to. Thereby, since the number of electrodes of the vibrator 21 can be reduced, the vibrator 21 is downsized.
Further, by connecting the metal film 52 on the substrate 40 and the circuit board 22, the electrical signals of the plurality of third electrodes 32 are taken out through the substrate 40, or the electrical signals of the plurality of third electrodes 32. Can be sent in a batch. Also in this case, the electrodes of the vibrator 21 can be reduced, and the vibrator 21 can be further downsized.

  FIG. 12 is a cross-sectional view showing another structure of the electrode portion 35. FIG. 12A shows the case where solder is used. FIG. 12B shows a case where wire bonding is used. Note that the structure of FIG. 12 may be adopted anywhere in the electrode portion 35.

  According to the structure of FIG. 12, electrical signals can be taken out from the first electrode 29 and the third electrode 32 at a time, or electrical signals can be sent in at a time. In particular, since the second electrode 31 is retracted with respect to the piezoelectric layer 30a and the piezoelectric layer 30b, even when a metal such as solder used for mounting is deformed, defects such as a short circuit can be suppressed, so that mounting reliability is improved. It can be improved.

  FIG. 13 is a diagram illustrating a method of manufacturing the drive electrode unit 26, the sensing electrode unit 27, and the monitor electrode unit 28. In step (a), an electrode is formed on a silicon substrate by sputtering or the like. As an electrode material, for example, platinum can be used.

  In step (b), a piezoelectric layer is formed on the electrode by sputtering or the like.

  In step (c), an electrode is formed on the piezoelectric layer by sputtering or the like.

  In step (d), a piezoelectric layer is formed on the electrode by sputtering or the like.

  In step (e), an electrode is formed on the piezoelectric layer by sputtering or the like.

  In step (f), a resist film is formed on the electrode.

In the step (g), patterning is performed by dry etching and the resist is removed.
Through the above steps, the drive electrode part 26, the sensing electrode part 27, and the monitor electrode part 28 described with reference to FIG. 4 can be manufactured.

  Further, there may be a step of patterning the electrode after the step (a), the step (c), and the step (e). In this case, the drive electrode part 26, the sensing electrode part 27, and the monitor electrode part 28 shown in FIG. 3 can be manufactured without using the step (g).

  Moreover, the drive electrode part 26, the sensing electrode part 27, and the monitor electrode part 28 which were demonstrated in FIG. 5 can be manufactured by adjusting the patterning process of a process (g).

  FIG. 14 is a diagram illustrating a method for manufacturing the electrode unit 35.

  In step (a), a resist film is formed on the structural portion manufactured in step (g) in FIG.

  In the step (b), the third electrode 32 is patterned by wet etching.

  In step (c), patterning is performed by dry etching up to the second electrode 31.

  In step (d), a resist film is formed on the structural part manufactured in step (c).

  In the step (e), the second electrode 31 is patterned by wet etching.

  In the step (f), patterning is performed by dry etching up to the first electrode 29.

In the step (g), the resist film is removed.
The electrode part 35 can be manufactured by the above process.

  FIG. 15 is a diagram illustrating another configuration of the electrode unit 35.

  In the case of FIG. 15, the second piezoelectric layer 30b included in the second electrode portion 35b has an opening. The opening provided in the piezoelectric layer 30 b included in the second electrode portion 35 b increases in diameter as the distance from the substrate 33 increases.

In the case of FIG. 15, an opening is provided in the second piezoelectric layer 30b of the first electrode portion 35a. The diameter of the opening provided in the piezoelectric layer 30 b of the first electrode portion 35 a increases as the distance from the substrate 33 increases. Further, the first piezoelectric layer 30a included in the first electrode portion 35a has an opening. The opening of the first piezoelectric layer 30 a of the first electrode portion 35 a has a diameter that increases as the distance from the substrate 33 increases. Thereby, even when a metal such as solder used for mounting is deformed, deformation of the solder can be suppressed, so that mounting reliability can be improved.
The structure shown in FIG. 15 can be formed by using wet etching when the piezoelectric layer is etched in steps (c) and (f) of FIG.

  Since the driving efficiency of the vibrator is improved, the present invention is useful as an angular velocity sensor using a piezoelectric thin film used in electronic equipment and the like.

DESCRIPTION OF SYMBOLS 21 Vibrator 22 Circuit board 23 Case 24 Base part 25 Arm part 26 Drive electrode part 27 Sensing electrode part 28 Monitor electrode part 29 1st electrode 30a, 30b Piezoelectric layer 31 2nd electrode 32 3rd electrode 33 Board | substrate 35 Electrode part 35a First electrode part 35b Second electrode part 35c Third electrode part 40 Substrate 51, 52 Metal film

Claims (14)

A substrate,
A first electrode provided on the substrate;
A first piezoelectric layer provided on the first electrode;
A second electrode provided on the first piezoelectric layer;
A second piezoelectric layer provided on the second electrode;
A third electrode provided on the second piezoelectric layer;
A circuit board;
With
The first, second, and third electrodes and the circuit board are electrically connected,
The first and third electrodes receive and input electrical signals from the circuit board,
The second electrode is an angular velocity sensor connected to a ground potential. A substrate,
A first electrode provided on the substrate;
A first piezoelectric layer provided on the first electrode;
A second electrode provided on the first piezoelectric layer;
A second piezoelectric layer provided on the second electrode;
A third electrode provided on the second piezoelectric layer;
A circuit board;
With
The first, second, and third electrodes and the circuit board are electrically connected,
The second electrode receives an electrical signal from the circuit board,
The first and third electrodes are angular velocity sensors connected to a ground potential.   3. The angular velocity sensor according to claim 1, wherein an end portion of the first piezoelectric layer has a portion extending from an end portion of the third electrode in a cross section. 3. The angular velocity sensor according to claim 1, wherein an end portion of the second electrode has a portion that is recessed from an end portion of the first piezoelectric layer in a cross section. 3. The angular velocity sensor according to claim 1, wherein an end portion of the first piezoelectric layer has a portion substantially coinciding with an end portion of the second piezoelectric layer 3. A first electrode portion where the first electrode is exposed on an upper surface;
A second electrode portion where the second electrode is exposed on the upper surface;
A third electrode part exposed on the upper surface of the third electrode;
The angular velocity sensor according to claim 1 or 2, wherein the third electrode portion is provided between the first electrode portion and the second electrode portion in a top view. The first electrode has a first electrode portion exposed on an upper surface;
3. The angular velocity sensor according to claim 1, wherein, in the first electrode portion, the second piezoelectric layer has an opening having a diameter that increases with distance from the substrate. The first electrode has a first electrode portion exposed on an upper surface;
In the first electrode portion, the first piezoelectric layer has an opening whose diameter increases as the distance from the substrate increases.
3. The angular velocity sensor according to claim 1, wherein, in the first electrode portion, the second piezoelectric layer has an opening having a diameter that increases with distance from the substrate. The second electrode has a second electrode portion exposed on an upper surface;
3. The angular velocity sensor according to claim 1, wherein, in the second electrode portion, the second piezoelectric layer has an opening having a diameter that increases with distance from the substrate. The first electrode has a first electrode portion exposed on an upper surface;
The angular velocity sensor according to claim 1, further comprising a metal member that connects the first electrode and the third electrode. The first electrode has a first electrode portion exposed on an upper surface;
A metal member that connects the first electrode and the third electrode;
The end of the second electrode included in the first electrode portion includes the end of the first piezoelectric layer included in the first electrode portion and the second piezoelectric layer included in the first electrode portion. The angular velocity sensor according to claim 1, wherein the angular velocity sensor is retracted with respect to an end of the sensor. A substrate having a first metal film having a first thickness and a second metal film having a second thickness;
The angular velocity sensor according to claim 1, wherein the second metal film is connected to the third electrode. The angular velocity sensor according to claim 1 or 2, wherein a polarization direction of the first piezoelectric layer and a polarization direction of the second piezoelectric layer are different from each other. The angular velocity sensor according to claim 1 or 2, wherein the first and second piezoelectric layers are formed using NBT-BT.

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