JP2008224628A - Angular velocity sensor and electronic device - Google Patents

Angular velocity sensor and electronic device Download PDF

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JP2008224628A
JP2008224628A JP2007067632A JP2007067632A JP2008224628A JP 2008224628 A JP2008224628 A JP 2008224628A JP 2007067632 A JP2007067632 A JP 2007067632A JP 2007067632 A JP2007067632 A JP 2007067632A JP 2008224628 A JP2008224628 A JP 2008224628A
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arm
electrode
angular velocity
velocity sensor
piezoelectric
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JP2007067632A
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Japanese (ja)
Inventor
Junichi Honda
Teruyuki Inaguma
Koji Suzuki
Kazuo Takahashi
順一 本多
輝往 稲熊
浩二 鈴木
和夫 高橋
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Sony Corp
ソニー株式会社
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Priority to JP2007067632A priority Critical patent/JP2008224628A/en
Publication of JP2008224628A publication Critical patent/JP2008224628A/en
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Abstract

<P>PROBLEM TO BE SOLVED: To provide an angular velocity sensor which can suppress leakage of vibration into a base part supporting an arm part. <P>SOLUTION: The angular velocity sensor 1 includes a support part 22, the arm parts 12A-12C which have three piezo-electric functional layers 15A-15C which are arranged in one direction extending from the support part 22, a fixing part 24 having a mounting surface 1A in which terminals 140-147 electrically connected to the piezo-electric functional layers 15A-15C are formed, and a relief part 23 which is connected with the support part 22 and the fixing part 24 is arranged between the support part 22 and the fixing part 24. The width along one direction of the relief part is narrower than the width along each one direction of the fixing part 24 and the support part 22. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to, for example, an angular velocity sensor used for detecting a camera shake of a video camera, a motion detection in a virtual reality device, a direction detection in a car navigation system, and the like, and more specifically, a three tuning fork type having three transducer arms. The present invention relates to an angular velocity sensor and an electronic device.
  Conventionally, as an angular velocity sensor for consumer use, a vibrator is vibrated at a predetermined resonance frequency, and a so-called vibration-type sensor that detects a missing speed by detecting a Coriolis force generated by the influence of the angular velocity with a piezoelectric element or the like is used. Gyro sensors are widely used. The vibration type gyro sensor has advantages such as a simple mechanism, short start-up time, and low cost manufacturing. For example, it is mounted on electrical equipment such as video cameras, virtual reality devices, car navigation systems, It is used as a sensor for motion detection and direction detection.
The following patent document discloses an angular velocity sensor having a three tuning fork vibrator.
JP-A-7-83671
  However, the angular velocity sensor having the three tuning fork vibrator described in Patent Document 1 has a problem that the vibration of the arm portion is transmitted to the base portion supporting the arm portion, thereby degrading the angular velocity detection characteristics.
  This invention is made in view of the above-mentioned problem, and makes it a subject to provide the angular velocity sensor and electronic device which can suppress the vibration leak to the base which supports an arm part.
  In solving the above problems, the angular velocity sensor of the present invention includes a support portion, an arm portion having three piezoelectric functional layers extending from the support portion and disposed along one direction, and the piezoelectric portion. A fixing part having a mounting surface provided with a terminal electrically connected to the functional layer, and a buffer part disposed between the supporting part and the fixing part and coupled to the supporting part and the fixing part, The width of the buffer portion along the one direction is narrower than the width of the fixed portion and the support portion along the one direction.
  The three arm portions constitute a tuning fork type vibrator. In the present invention, by providing the buffer portion, the vibration of each arm portion can be suppressed from being transmitted to the fixed portion, and a stable angular velocity detection operation can be realized.
  Further, the fixing portion is characterized in that a thickness along a direction orthogonal to the mounting surface is thicker than thicknesses of the arm portion, the support portion, and the buffer portion. Thereby, it can further suppress that the vibration of each arm part is transmitted to a fixed part.
  Further, the wiring connecting the piezoelectric functional layer and the terminal has a line-symmetric shape. Thereby, the whole vibration state can be made into a thing without a twist, and a vibration can be stabilized.
  The angular velocity sensor of the present invention is formed on a base, three arm portions integrally extending from the base in substantially the same direction, a lower electrode layer formed on the arm portion, and the arm portion. A piezoelectric layer formed on the lower electrode layer; a drive electrode formed on the piezoelectric layer of at least two of the three arm portions; and the three arm portions. A detection electrode for detecting an angular velocity formed on the piezoelectric layer of the arm portion located at least in the center, and a wiring electrically connected to each of the lower electrode layer, the piezoelectric layer, the drive electrode, and the detection electrode The wirings are arranged in a line symmetrical shape.
  By arranging the wirings in a line-symmetric shape in this way, the entire vibration state can be made free of twist, the vibration can be stabilized, and a stable angular velocity detection operation can be realized.
  The electronic device of the present invention is electrically connected to the support portion, an arm portion having three piezoelectric function layers extending from the support portion and disposed along one direction, and the piezoelectric function layer. A fixed portion having a mounting surface provided with a terminal; and a buffer portion disposed between the support portion and the fixed portion and coupled to the support portion and the fixed portion; and the one direction of the buffer portion The width along the line includes an angular velocity sensor that is narrower than the width along the one direction of each of the fixed portion and the support portion, and a device main body on which the angular velocity sensor is mounted.
  Such an electronic device has a stable angular velocity detection operation because the mounted angular velocity sensor suppresses the vibration of each arm portion from being transmitted to the fixed portion by the buffer portion.
  Another electronic device according to the present invention includes a base, three arm portions integrally extending from the base in substantially the same direction, a lower electrode layer formed on the arm portion, and formed on the arm portion. A piezoelectric layer formed on the lower electrode layer formed, a drive electrode formed on the piezoelectric layer of at least two arm portions located on the outer side of the three arm portions, and the three A detection electrode for detecting an angular velocity formed on the piezoelectric layer of the arm portion located at least in the center of the arm portion, and a wiring electrically connected to each of the lower electrode layer, the piezoelectric layer, the drive electrode, and the detection electrode; An angular velocity sensor in which the wirings are arranged in a line-symmetric shape, and a device main body on which the angular velocity sensor is mounted.
  In such an electronic device, since the mounted angular velocity sensor is provided with a line-symmetrical wiring, the entire vibration state can be made free of twist and can stabilize the vibration. Has detection action
  As described above, according to the present invention, it is possible to realize a stable angular velocity detection operation by suppressing the vibration of each arm portion from being transmitted to the base portion.
  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following embodiment, A various deformation | transformation is possible based on the technical idea of this invention. Further, in the following drawings, in order to make each configuration easy to understand, some of the structures are not illustrated or the scales and the like of each structure are different from those of an actual structure.
  FIG. 1A is a bottom view showing a schematic configuration of an angular velocity sensor 1 according to an embodiment of the present invention, and FIG. 1B is a side view showing a schematic configuration of the angular velocity sensor 1. In FIG. 1A, a single crystal silicon layer, a detection electrode, a reference electrode, a drive electrode, a lower electrode film, a lead wiring, an external connection terminal, and a gold bump are illustrated, and other configurations are not illustrated. In addition, the planar shapes of the detection electrode, the reference electrode, and the base electrode film are illustrated in a simplified manner, and are different from those described in the manufacturing method of the angular velocity sensor 1 described later. In FIG. 1B, only the single crystal Si layer and the bump are shown, and the other configurations are not shown.
  2 is a cross-sectional view taken along line 2-2 in FIG.
  FIG. 3 is a block diagram showing the configuration of the drive detection circuit of the angular velocity sensor 1. In FIG. 3, the angular velocity sensor 1 shows only the arm portions 12 </ b> A to 12 </ b> C and the support portion 22 that is a part of the base portion 11.
  FIG. 4 is a cross-sectional view showing a schematic configuration in a state where the angular velocity sensor 1 is mounted on the mounting substrate 160.
As shown in FIG. 1, the angular velocity sensor 1 of the present embodiment includes a base portion 11 and three arm portions 12 </ b> A having a quadrangular cross section integrally extending from the base portion 11 in substantially the same direction (y-axis direction). , 12B, 12C. The arm portions 12A to 12C are arranged with a gap along one direction (x-axis direction). The base 11 and the arm portions 12 </ b> A to 12 </ b> C have a single crystal Si layer 61. The base portion 11 and the arm portions 12A to 12C are cut out in a predetermined shape from a non-doped Si single crystal substrate having no piezoelectric characteristics, and a piezoelectric functional layer and various lead wiring portions described later are formed on one surface, An angular velocity sensor 1 is configured. As the single crystal Si substrate, for example, a substrate having a resistance value of 1 MΩ / cm 2 can be used. Further, in the Si single crystal substrate, the surface corresponding to the bottom surface portion 1A serving as the mounting surface of the angular velocity sensor 1 is the (100) azimuth plane, and the cross section corresponding to the side surface portion 1B of the angular velocity sensor 1 is the (110) azimuth surface. It has become. By using a single crystal Si substrate having such an azimuth plane, it is possible to form angular velocity sensors 1 having partially different z-axis thicknesses by a manufacturing method described later.
  The arm parts 12 </ b> A to 12 </ b> C constitute a vibrator of the angular velocity sensor 1. In the present embodiment, each of the arm portions 12A to 12C is formed with, for example, the same arm length, formation width, and formation thickness, but is not limited thereto. For example, in order to reduce noise, the formation width of each arm may be different between the central arm portion and the outer arm portion. In the following description, out of these three arm portions 12A to 12C, the two arm portions 12A and 12B located outside are referred to as outer arm portions 12A and 12B, respectively, and the arm portion 12C located in the center is designated as the central arm. This will be referred to as part 12C.
  As shown in FIG. 1 and FIG. 4, the base 11 is fixed in which support portions 22 that support the three arm portions 12 </ b> A to 12 </ b> C and external connection terminals 140 to 147 that are electrically connected to the mounting substrate 160 are formed. It is comprised by the part 24 and the buffer part 23 formed between the support part 22 and the fixing | fixed part 24. As shown in FIG. Lead wires 133a, 133b, 133c, 134a, and 134b that electrically connect the electrodes formed on the arm portions 12A to 12C and the external connection terminals 140 to 147 are provided on the support portion 22, the buffer portion 23, and the fixing portion 24. 137a, 137b, 137c and dummy lead wiring 138 are formed.
  As shown in FIGS. 1 and 2, the outer arms 12A and 12B include single crystal Si layers 61a and 61b, a thermal oxide layer 62a provided thereon, and a piezoelectric functional layer 15A provided thereon. 15B and a protective layer 67 covering the same. The piezoelectric functional layers 15A and 15B include lower electrode layers 17a and 17b formed on the single crystal Si layers 61a and 61b, piezoelectric layers 16a and 16b formed on the lower electrode layers 17a and 17b, and the piezoelectric layers. The driving electrodes 13a and 13b are formed on the layers 16a and 16b.
  On the other hand, the central arm portion 12C includes a single crystal Si layer 61c, a thermal oxidation layer 62a provided thereon, a piezoelectric functional layer 15C provided thereon, and a protective layer 67 covering the same. Yes. The piezoelectric functional layer 15C includes a lower electrode layer 17c formed on the single crystal Si layer 61c, a piezoelectric layer 16c formed on the lower electrode layer 17c, and a reference electrode formed on the piezoelectric layer 16c. 13c and detection electrodes 14a and 14b. The detection electrodes 14a and 14b are respectively formed at left and right target positions with respect to the reference electrode 13c disposed on the axis of the central arm portion 12C.
  In the fixing portion 24, a thermal oxide layer 62a is formed on the single crystal Si layer 61, and a protective layer 67 and external connection terminals 140 to 147 are sequentially formed thereon.
  Further, the support portion 22, the buffer portion 23, and the fixing portion 24 include a thermal oxide layer 62a (not shown) on the single crystal Si layer 61, a protective layer 67 thereon, and further lead wires 133a, 133b thereon. 133c, 134a, 134b, 137a, 137b, 137c and dummy lead wiring 138 are formed.
  The left arm drive lead wire 133a electrically connects the drive electrode 13a and the external connection terminal 141. The right arm drive lead wiring 133b electrically connects the drive electrode 13b and the external connection terminal 145. The central arm drive lead wiring 133c electrically connects the reference electrode 13c and the external connection terminal 147. The center arm left detection lead wire 134a electrically connects the detection electrode 14a and the external connection terminal 143. The center arm right detection lead wire 134b electrically connects the detection electrode 14b and the external connection terminal 146. The left arm lower electrode lead wiring 137a electrically connects the lower electrode layer 17a and the external connection terminal 140. The right arm lower electrode lead wiring 137b electrically connects the lower electrode layer 17b and the external connection terminal 144. The center arm lower electrode lead wiring 137c electrically connects the lower electrode layer 17c and the external connection terminal 142. One end of the dummy lead wiring 138 is electrically connected to the lower electrode layer 17c, and the other end is not connected to the external connection terminal.
  The lead wirings 133a, 133b, 133c, 134a, 134b, 137a, 137b, 137c and the dummy lead wiring 138 are provided in a region where no piezoelectric film is formed so as not to overlap in a plane. As a result, the leakage signal is suppressed and unnecessary stray capacitance is not formed.
  In the present embodiment, as shown in FIG. 1, the various electrodes, lead wirings, and dummy lead wirings have a substantially symmetrical line symmetry with the substantially center line of the central arm portion 12 </ b> C as the symmetry axis. The formation area ratio of the electrode and the lead wiring is 1 to 1.1. As a result, the entire vibration state can be made free of twists, the vibration can be stabilized, and stable characteristics can be obtained. In addition, when it is difficult to make a line-symmetric shape by design, the formation area ratio on the left and right may be designed to be 1 to 1.1.
  As shown in FIG. 3, the angular velocity sensor 1 is driven and controlled by a control unit 31A such as an IC drive circuit element. The lower electrode layers 17a to 17c of the arm portions 12A to 12C are connected to the Vref terminal of the control unit 31A, respectively. The Vref terminal constitutes a ground terminal serving as a reference electrode. The drive electrodes 13a and 13b on the outer arm portions 12A and 12B are respectively connected to the G0 terminal of the control unit 31A, and the drive signal generated by the self-excited transmission circuit 32 is input thereto. Further, the reference electrode 13c for detecting the vibration characteristic of the central arm portion 12C is connected to the G1 terminal, and the detection electrodes 14a and 14b are connected to the Ga and Gb terminals, respectively. The Ga, Gb, and G1 terminals are connected to the arithmetic circuit 33. The arithmetic circuit 33 feeds back the output of the reference electrode 13c as a driving signal to the self-excited oscillation circuit 32, and outputs the differential signal of the detection electrodes 14a and 14b to the angular velocity. The signal is output to the detection circuit 36. The detection signal signal-processed by the detection circuit 36 is supplied to the smoothing circuit 37 and then processed as an angular velocity signal.
  The angular velocity sensor 1 is connected to the control unit 31 </ b> A through the mounting substrate 160. In the present embodiment, as shown in FIG. 20, the angular velocity sensor 1 is flip-chip mounted on the mounting substrate 160 on which the IC element 31 constituting the control unit 31A is mounted. The plurality of bumps 50 used for flip chip mounting are formed on the external connection terminals 140 to 147 provided on the base 11 of each speed sensor 1. As shown in FIG. 1, on the mounting surface of the base portion 11, a lead wiring 133 a that electrically connects the piezoelectric functional layers 15 </ b> A to 15 </ b> C of the arm portions 12 </ b> A to 12 </ b> C and the plurality of external connection terminals 140 to 147. 133b, 133c, 134a, 134b, 137a, 137b, 137c and dummy lead wiring 138 are formed.
  A common drive signal is input to the drive electrodes 13a and 13b on the outer arm portions 12A and 12B. Thereby, due to the reverse piezoelectric effect of the piezoelectric layers 16a and 16b, the outer arm portions 12A and 12B are in a direction (z-axis direction) perpendicular to the film surfaces of the piezoelectric functional layers 15A and 15B (piezoelectric layers 16a and 16b). Excited in phase.
  The central arm portion 12C receives the reaction of the vibrations of the outer arm portions 12A and 12B, and similarly vibrates in the opposite direction to the outer arm portions 12A and 12B in the z-axis direction. At this time, the reference electrode 13c and the detection electrodes 14a and 14b electrically detect the vibration characteristics of the arm portion 12C by the piezoelectric effect of the piezoelectric layer 16c, and the reference signal detected via the reference electrode 13c The difference signal of the detection signal fed back to the self-excited oscillation circuit 32 in 31A and detected via the detection electrodes 14a and 14b is processed as an angular velocity signal. When the angular velocity signal is not applied, the difference signal between the detection electrodes 14a and 14b is zero in principle.
  On the other hand, in this state, when an angular velocity acts around the y-axis direction, a Coriolis force is generated in each arm portion 12A, 12B, and each arm portion 12A-12C is in a direction balanced with the formation surface of the piezoelectric functional layers 15A-15C ( A component that vibrates in the x-axis direction) is generated. This vibration component is detected by the detection electrodes 14a and 14b using the piezoelectric effect of the piezoelectric layer 16c on the central arm portion 12C, and the magnitude and direction of each speed are detected based on the difference signal.
  In the present embodiment, the operating frequency of each of the arm portions 12A to 12C, that is, the resonance frequency in the z-axis direction (hereinafter referred to as “longitudinal resonance frequency”) fv in the basic mode is set to the same frequency. The angular velocity detection frequency, that is, the resonance frequency (hereinafter referred to as “lateral resonance frequency”) fh in the x-axis direction of each of the arms 12A to 12C is set near the longitudinal resonance frequency fv only for the central arm 12C. The outer arm portions 12A and 12B are set apart from the longitudinal resonance frequency fv by several hundred to several kiloHz.
  As described above, in the angular velocity sensor 1 of the present embodiment, when vibrating in the basic mode, the outer arm portions 12A and 12B are excited in the same phase, and the central arm portion 12C is excited in the opposite phase to the outer arm portions 12A and 12B. Is done. Also, at the time of angular velocity detection, the vibration direction of the central arm portion 12C is opposite to the vibration direction of the outer arm portions 12A and 12B. Therefore, according to the present embodiment, a rotational moment is generated by vibration between the arm portions 12A to 12C, but the rotational moment generated between the one outer arm portion 12A and the central arm portion 12C and the other outer portion. Since the rotational moments generated between the arm part 12B and the central arm part 12C are in opposite directions, the vibration transmitted to the base part 11 can be greatly reduced as a result.
  In the angular velocity sensor 1 of the present embodiment, the excitation direction of the arm portions 12A to 12C by the drive electrodes 13a and 13b is set to a direction (z-axis direction) perpendicular to the formation surface of the piezoelectric functional layers 15A to 15C. Therefore, unlike the detection direction (x-axis direction), it can be vibrated in an inherently stable vibration mode. That is, the rigid center of vibration excitation by the piezoelectric layers 16a and 16b coincides with the center of gravity of the arm portions 12A and 12B, so that the first direction (z-axis direction) perpendicular to the formation surface of the piezoelectric functional layers 15A and 15B. This facilitates excitation of the arm portions 12A and 12B as compared with the second direction (x-axis direction) parallel to the formation surfaces of the piezoelectric functional layers 15A and 15B. For this reason, it is possible to suppress the vibration transition in the second direction even when the driving frequency fluctuates due to the superposition of disturbance, and to maintain a stable basic mode. Thereby, an angular velocity sensor that is strong against disturbance can be configured, and high-accuracy output characteristics can be stably obtained.
  Further, in the present embodiment, the lateral resonance frequency fh is set near the longitudinal resonance frequency fv only for the central arm portion 12C, and the transverse resonance frequency fh for the outer arm portions 12A and 12B is set away from the longitudinal resonance frequency fv. Therefore, the detection accuracy of the angular velocity can be improved, and at the same time, the vibration direction in the basic operation mode of the outer arms 12A and 12B can be stabilized.
  The angular velocity sensor 1 is mounted by electrically connecting the external connection terminals 140 to 147 to the mounting substrate 160 through, for example, gold bumps 40 to 47.
  The buffer portion 23 is configured with a width smaller than the formation width along the x-axis direction (one direction) of the support portion 22 and the fixing portion 24. Furthermore, the fixing portion 24 is configured with a width larger than the formation width of the support portion 22 along the x-axis direction. In other words, the shape of the angular velocity sensor 1 in the xy plane shape has a constricted portion 51 by the buffer portion 23. In this way, by configuring the buffer portion 23 with a width smaller than the formation width of the support portion 22 and the fixing portion 24, the external connection terminals 140 to 140 are supported from the support portion 22 that supports the base portions of the arm portions 12A to 12C. It becomes possible to suppress the transmission of vibration to the fixing part 24 provided with the formation region 147. As a result, it is possible to significantly reduce the amount of vibration leakage to the mounting substrate 160 and improve the angular velocity detection characteristics. Further, by configuring the fixing portion 24 with a width larger than the formation width of the support portion 22, the distance between the external connection terminals 140 to 143 located on the left side in the drawing and the external connection terminals 144 to 147 located on the right side. Can be spread.
  As shown in FIG.1 (b), in this embodiment, the thickness (z-axis direction) of the three arm parts 12A-12C, the support part 22, and the buffer part 23 is the same, The thickness a is 100 micrometers. is there. On the other hand, the thickness b (z-axis direction) of the fixing portion 24 is configured to be 200 μm, which is larger than the thickness a of the three arm portions 12A to 12C, the support portion 22, and the buffer portion 23. As described above, by increasing the thickness of the fixing portion 24, it is possible to further suppress the leakage of vibration from the arm portions 12A to 12C to the fixing portion 24.
  Here, FIG. 5 shows the relationship between the thickness b of the fixing portion 24 and the vibration amount of the mounting substrate 160. As shown in FIG. 5, by increasing the thickness of the fixing portion 24, the vibration amount of the mounting substrate 160 can be reduced, and as a result, the proximity noise can be reduced.
  In addition, the length from the base of the arm portions 12A to 12C to the boundary portion between the fixed portion 24 and the buffer portion 23, in other words, the length c in the y-axis direction of the support portion 22 and the buffer portion 23 in the present embodiment. Is configured to be 500 μm. FIG. 6 is a diagram showing the relationship between the length c and the thickness b of the fixing portion 24 where the vibration amount of the mounting substrate 160 is 5 nm or less and the proximity noise is 20 mV or less. As shown in FIG. 6, it is necessary to increase the length c when the thickness b of the fixing portion 24 is thin, and it is possible to shorten the length c when the thickness of the fixing portion 24 is thick. In addition, by reducing the length c, the area of the planar shape of the angular velocity sensor can be reduced, so that the number of single crystal silicon wafers can be increased.
  In the present embodiment, the distance d between the arm terminals 12A to 12C is 50 to 200 μm. There is no practical design with a value larger than 200 μm. Further, although the value at which the Q value is saturated varies depending on the dimensions of the arm portion, the Q value is saturated by setting it to 50 μm or more. Here, FIG. 21 shows the relationship between the arm terminal distance (arm interval) and the responsiveness, FIG. 22 shows the relationship between the arm interval and the Q value, and FIG. 23 shows the arm when the cross-sectional area of the arm part is different. FIG. 24 shows the relationship between the interval and the Q value, and FIG. 24 shows the relationship between the arm interval and the Q value when the length of the arm portion is varied. From FIG. 21 and FIG. 22, it can be seen that the arm interval and the Q value are favorable, and the Q value and the response are also correlated. From FIG. 23 and FIG. 24, the value at which the Q value saturates varies depending on dimensions such as the cross-sectional area and length of the arm portion, but the Q value saturates when the arm interval is 50 μm or more.
  FIG. 7 is a schematic plan view for explaining the shape of the detection electrode, reference electrode, and drive electrode of the angular velocity sensor 1 shown in FIG.
  As shown in FIG. 7, a reference electrode 13c is provided substantially at the center of the central arm portion 12C, and detection electrodes 14a and 14b are provided on both sides of the reference electrode 13c. A central arm left detection lead wire 134a and a central arm right detection lead wire 134b that are electrically connected to the detection electrodes 14a and 14b on both sides of the central arm drive lead wire 133c that is electrically connected to the reference electrode 13c, respectively. Is provided.
  The detection electrode 14a and the detection electrode 14b, and the central arm left detection lead wire 134a located on the left side in the drawing and the central arm right detection lead wire 134b located on the right side are electrically connected to the detection electrode 14a and the detection electrode 14b, respectively. Are the same in thickness and have almost the same formation area. In this way, by setting the area ratio of the central arm left detection lead wire 134a and the central arm right detection lead wire 134b located on the right side to 1 to 1.1, the leak signal leaking from the drive electrode to the detection electrode is made the same. Power supply suppression ratio can be suppressed. 8 to 12 show various changes measured when the drive electrodes 13a and 13b, the reference electrode 13c, and the lead wirings 133a, 133b, and 133c are made constant. FIG. 8 is a diagram showing the relationship between the area ratio of lead wires connected to the left and right detection electrodes and the leakage current. FIG. 9 is a diagram illustrating the relationship between the area ratio of the lead wirings connected to the left and right detection electrodes and the difference between the left and right leakage currents. FIG. 10 is a diagram illustrating the relationship between the left and right leakage current difference and Null. FIG. 11 is a diagram illustrating the relationship between Null and PSRR. FIG. 12 is a diagram illustrating the relationship between the area ratio of lead wires connected to the left and right detection electrodes and PSRR. As can be seen from these figures, it is desirable that the area ratio of the detection electrodes and the lead wires connected to the detection electrodes is 1 to 1.1.
  Further, as shown in FIG. 7, the outer arm portions 12A and 12B are provided with drive electrodes 13a and 13b, respectively. The drive electrode 13a and the left arm drive lead wire 133a electrically connected to the drive electrode 13a, and the drive electrode 13b and the right arm drive lead wire 133b electrically connected to the drive electrode 13a include the reference electrode 13c and the central arm drive lead wire 133c. They are provided in a line-symmetric relationship that is substantially symmetrical with respect to the axis of symmetry. Thus, the left arm drive lead wire 133a located on the left side in the drawing and the right arm drive lead wire 133b located on the right side, which are electrically connected to the drive electrodes 13a and 13b, respectively, have the same thickness. The wiring area is almost equal. Thus, by making the area ratio of the left arm drive lead wire 133a and the right arm drive lead wire 133b approximately 1: 1, PSRR (Power Supply Rejection Ratio) can be reduced. FIG. 13 is a diagram showing the relationship between the area ratio of lead wires connected to the left and right drive electrodes and PSRR. As can be seen from this figure, it is desirable that the area ratio of the left arm drive lead wire 133a and the right arm drive lead wire 133b is 1 to 1.1.
  FIG. 14 is a schematic plan view for explaining the shape of the lower electrode layer of the angular velocity sensor 1 shown in FIG. 1 and the lead wiring electrically connected thereto.
As shown in FIG. 14, the lower electrode layers 17a, 17b, and 17c are provided in the respective arm portions 12A to 12C. A central arm lower electrode lead wiring 137c and a dummy lead wiring 138 are electrically connected to the lower electrode layer 17c provided in the central arm portion 12C, and the central arm lower electrode lead wiring 137c and the dummy lead wiring 138 are connected to each other. It has a substantially line-symmetric shape. A left arm lower electrode lead wire 137a and a right arm lower electrode lead wire 137b are provided on both sides of the central arm lower electrode lead wire 137c and the dummy lead wire 138 so as to be electrically connected to the lower electrode layers 17a and 17b. It has been. The left arm lower electrode lead wiring 137a and the right arm lower electrode lead wiring 137b have a line-symmetric shape. As shown in FIG. 1, a central arm lower electrode lead wire 137c and a dummy lead wire 138 are provided on both sides so as to sandwich the lead wires 134a, 133c, and 134b, and a left arm drive lead wire is provided on both sides so as to further sandwich them. 133a and a right arm drive lead wire 133b are provided, and a left arm lower electrode lead wire 137b and a right arm lower electrode lead wire 137b are provided on both sides so as to sandwich them. The lead wires 137a, 133a, 137c, and 134a, the lead wires 137b and 133b, the dummy lead wire 138, and the lead wire 134b are provided in line symmetry with the central arm drive lead wire 133c as an axis of symmetry. By providing the dummy lead wiring 138 in which the external connection terminal and the other end are not connected so as to be symmetrical in this way, the leakage signal from the adjacent drive electrode 13b can be blocked from entering the detection signal. it can. The dummy lead wiring 138 is grounded via the central arm lower electrode lead wiring 137c in order to be electrically connected to the lower electrode layer 17c. FIG. 15 shows the results of measuring PSRR with and without the dummy lead wiring 138 being provided. As shown in FIG. 15, when dummy lead wiring is provided, PSRR can be reduced.
  Further, in the present embodiment, the piezoelectric layers 16a to 16c have independent island shapes, and have a line-symmetric shape. As a result, the polarization is performed in each of the piezoelectric functional layers 15A to 15C, and the vibration is inverted between the central arm portion 12C and the outer arm portions 12A and 12B in order to vibrate independently.
  In the present embodiment, the three arm portions 12A to 12C of the vibrator of the angular velocity sensor 1 have the same piezoelectric polarization direction as shown in FIG. 16 is a diagram illustrating a wiring state of the angular velocity sensor 1, and FIG. 17 is a cross-sectional view taken along a line 17-17 in FIG. 16 and illustrates a wiring state in the mounting substrate 160. On the other hand, as shown in FIG. 18, the piezoelectric polarization direction may be the same for the outer arm portions 12A and 12B, and the central arm portion 12C may be the opposite piezoelectric polarization direction. 18 is a diagram showing a wiring state of the angular velocity sensor 1, and FIG. 19 is a cross-sectional view taken along line 18-18 of FIG. In this embodiment, for example, a plurality of ground lead wires are not connected to one external connection terminal at a time, but an external connection terminal is provided for each ground lead wire. The grounded lead wires are separated from each other. Accordingly, as shown in FIGS. 16 to 19, when the piezoelectric polarization direction is changed, it is possible to deal with the wiring substrate common to the mounting substrate 160 side without changing the electrode structure of the angular velocity sensor 1.
  In this embodiment, the angular velocity sensor 1 is mounted on the mounting substrate 160 by flip chip bonding using eight bumps. Since a load is applied in mounting, the fixing portion 24 to which the load is applied needs to have a thickness that can withstand the load. For example, when connecting 8 bumps, a thickness of 180 μm or more is preferable.
  Further, in this embodiment, eight bumps are used, but a common wiring is formed on the angular velocity sensor by electrically connecting a plurality of grounded lead wirings to one external connection terminal at a time. It is also possible to reduce the number of bumps provided. However, in this case, it is conceivable that the number of processes increases and the wiring overlaps in a plane, thereby causing a short circuit failure and stray capacitance. In this embodiment, since there is no common wiring on the angular velocity sensor, there are no problems such as short circuit failure and stray capacitance, and the manufacturing can be performed with a simple manufacturing process. In addition, it is easy to provide symmetry to the shape of the electrode and the lead wiring by design. In the present embodiment, there are eight bumps. Since the mounting strength increases as the number of bumps increases, the mounting strength is higher than when the common wiring is provided on the angular velocity sensor to reduce the number of bumps.
  Next, a manufacturing example of the angular velocity sensor 1 of the present embodiment configured as described above will be described. FIG. 25 is a main process flow for explaining the manufacturing method of the angular velocity sensor 1.
  [Board preparation process]
  First, a non-doped single crystal Si substrate 161 as shown in FIGS. 26A and 26B is prepared. The size of the Si substrate 161 is arbitrarily set according to the line of the thin film process possessed, and a wafer having a diameter of 4 inches is used in this embodiment. Although the thickness of the Si substrate 161 is determined by workability and cost, it may be finally larger than the thickness of the vibrator, and in this embodiment, the thickness is 300 μm.
Thermal oxide films (SiO 2 films) 162a and 162b serving as protective masks for anisotropic wet etching are formed on both surfaces of the Si substrate 161. The thickness of the thermal oxide films 162a and 162b is arbitrary, but in the present embodiment, it is about 0.3 μm. Further, with respect to the azimuth plane of the Si substrate 161, the substrate wide-mouth plane shown in FIG. 26A is the (100) azimuth plane, and the plane of FIG. 26B, which is a cross section of the Si substrate 161, is the (110) plane. The substrate is cut out.
  [Diaphragm formation process]
  Next, as shown in FIGS. 27A and 27B, in order to remove a part of the thermal oxide film 162b on the back surface of the Si substrate 161, a resist pattern film 163 is formed with the removed portion as an opening. To do. The resist pattern film 3 is formed by a photolithography technique used in a normal semiconductor thin film formation process. As the resist material, for example, OFPR-8600 manufactured by Tokyo Ohka Co., Ltd. was used, but the type is not limited to this. The photolithography process is a technique generally used in a thin film forming process of resist material application, pre-baking, exposure, and development, and details thereof are omitted here. In the subsequent processes, photolithography technology is used, but general steps are omitted except for a special method of use.
  Each of the openings shown in FIG. 27A is one angular velocity sensor. The shape of the opening is determined by the final arm shape, the thickness of the Si substrate 161, and the etching width when forming the arm shape (vibrator).
  Next, as shown in FIGS. 28A and 28B, the thermal oxide film 162b corresponding to the opening is removed. The removal method may be physical etching such as ion etching or wet etching, but considering the smoothness of the interface of the Si substrate 161, wet etching in which only the thermal oxide film 162b is removed is preferable. In this embodiment, ammonium fluoride is used as a chemical solution for wet etching. However, in the case of wet etching, when etching is performed for a long time, so-called side etching in which etching proceeds from the side surface of the opening portion becomes large. Therefore, it is necessary to finish the etching when only the opening portion of the thermal oxide film 162b is removed. is there.
  Next, as shown in FIGS. 29A, 29B and 30, wet etching is performed on the Si substrate 161 exposed as the opening portion, thereby reducing the thickness of the Si substrate 161 in the opening portion to a desired arm. Sharpen until the thickness of the part is reached. In this embodiment, a TMAH (tetramethylammonium hydroxide) 20% solution is used to etch the substrate 161 made of Si. At this time, immersion temperature etching is performed while maintaining the liquid temperature at 80 ° C.
  FIG. 30 is an enlarged view of a portion W in FIG. In order to set the etching amount (diaphragm depth) t10 to 200 μm under the above conditions, etching was performed for about 6 hours. Further, by this etching, the shape of the Si substrate 161 at the opening is formed with the end portion having a wet etching angle θ1 (= 55 °) as shown in FIG. In addition to TMAH, KOH (potassium hydroxide) or EDP (ethylenediamine-pyrocatechol-water) solution or the like can be used as such a wet etching chemical, but in this embodiment, the etching rate with the thermal oxide films 162a and 162b is high. TMAH with a higher selection ratio was adopted.
  By the way, in this embodiment, wet etching utilizing the characteristics of Si is adopted for substrate grinding until the thickness of the arm portion is reached, but the grinding method is arbitrary and is not limited to this abundance.
  A diaphragm is formed in the opening by the above method. The diaphragm thickness t11 left by the wet etching finally becomes equal to the arm portion thickness.
  In the following description, one element indicated by W in FIGS. 29A and 29B will be described in an enlarged manner. Moreover, in order to make the explanation easy to understand in the drawings, there are cases where the actual dimensional ratio is different. Further, as shown in FIGS. 31 (a) and 31 (b), description will be made with the diaphragm opening and the thermal oxide film 162b formed so far downward.
  [Electrode film forming step]
  Next, as shown in FIGS. 31A and 31B, a lower electrode film 117, a piezoelectric film 116, and an upper electrode film 113 are formed. In order to improve the characteristics of the piezoelectric film, the lower electrode film 117 includes a Ti (titanium) film (film thickness of 50 nm or less, for example, 20 nm) as a base film and an Au (gold) film (on the Ti film). A laminated film having a thickness of 100 nm). In addition to Au, other metal films such as Pt, Rh (rhodium), and Re (rhenium) are applicable, and in addition to Ti, Ta (tantalum) and the like are also applicable.
  In the step of forming the lower electrode film 117, first, a Ti film having a thickness of 20 nm was formed using a magnetron sputtering apparatus, and a Au film having a thickness of 100 nm was formed on the Ti film. Ti and Au were formed with a gas pressure of 0.5 Pa and RF (Radio Frequency) power (high frequency power) of 1 kW and 0.5 kW, respectively.
  Next, the piezoelectric film 116 is formed. In the formation process of the piezoelectric film 116, an oxide target of Pb1.02 (Zr0.53Ti0.47) O3 is used with a magnetron sputtering apparatus, the room temperature, the oxygen gas pressure is 0.2 to 3 Pa, and the RF power is 0.1 to 5 kW. The piezoelectric film 116 was formed to a thickness of 1.4 μm under the conditions.
  In the step of forming the upper electrode film 113, a Ti film of 20 nm was formed on the surface of the piezoelectric film 116 formed as described above, and an Au film was formed on the Ti film to a thickness of 100 nm. Ti and Au were formed by a magnetron sputtering apparatus under conditions of a gas pressure of 0.5 Pa and an RF power of 0.5 kW.
  [Electrode film processing process]
  Next, as shown in FIGS. 32A and 32B, the formed upper electrode film 113 is processed into a predetermined shape. As a result, as shown in FIG. 32A, the drive electrodes 13a and 13b, the reference electrode 13c, and the detection electrodes 14a and 14b are formed. The drive electrodes 13a and 13b, the reference electrode 13c, and the detection electrodes 14a and 14b each have a substantially linear shape extending along the y-axis direction, and a wiring connection portion 63 is provided at an end portion on the base 11 side of each electrode. Is provided.
  As a processing method of the upper electrode film 113, a desired resist pattern film was formed by using a photolithography technique, and then an unnecessary portion of the upper electrode film 113 was removed by ion etching. The processing method of the upper electrode film 113 is not particularly limited.
  Next, as shown in FIGS. 33A and 33B, the piezoelectric film 116, the lower electrode film 117, and the thermal oxide film 162a are collectively processed into a predetermined shape to form lower electrode layers 17a to 17c. The shape of the piezoelectric film 116, the lower electrode film 117, and the thermal oxide film 162a is arbitrary as long as the drive electrodes 13a and 13b, the reference electrode 13c, and the detection electrodes 14a and 14b are completely positioned in the plane. As a processing method of the piezoelectric film 116, the lower electrode film 117, and the thermal oxide film 162a, a resist pattern film having the shape of the piezoelectric film 116, the lower electrode film 117, and the thermal oxide film 162a is formed by using a photolithography technique. In the embodiment, it is removed by wet etching using a hydrofluoric acid solution. The removal method is arbitrary, and removal by physical ion etching or chemical removal by RIE (Reactive Ion Etching) can be considered.
  Next, as shown in FIGS. 34A and 34B, a part of the piezoelectric film 116 having the same planar shape as the lower electrode layers 17a, 17b, and 17c is processed and removed, and the piezoelectric layer 16a is removed. , 16b, 16c are formed. Each of the piezoelectric layers 16a to 16c has an independent island shape, and has a line-symmetric shape. By this step, as shown in the drawing, a part of the lower electrode layers 17a to 17c on the base 11 side is exposed. As a processing method of the piezoelectric film 116, a resist pattern film having a desired shape is formed by using a photolithography technique, and in this embodiment, the resist pattern film is removed by wet etching using a hydrofluoric acid solution. The removal method is arbitrary, and removal by physical ion etching or chemical removal by RIE (Reactive Ion Etching) can be considered.
  [Protective layer forming step]
Next, a protective layer 67 composed of three layers of Al 2 O 3 / SiO 2 / Al 2 O 3 having a resistance value of 500 MΩ / cm 2 or more is formed. This protective layer serves as a base film for ensuring the adhesion of the wiring electrode film, which will be described later, and the drive electrodes 13a and 13b, the reference electrode 13c, the detection electrodes 14a and 14b, and the lower electrode layer excluding the electrode connecting portion 63 portion. It has a role as a protective film that covers the electrodes 17a to 17c to prevent leakage between electrodes due to external factors such as humidity and to prevent oxidation of the electrode film. That is, in this embodiment, since the base film and the protective film are formed in a lump without forming them in separate steps, the manufacturing process can be simplified. In addition, by setting the resistance value of the protective layer 67 to 500 MΩ / cm 2 or more, it is possible to suppress the occurrence of ion migration including humidity in the atmosphere.
As shown in FIG. 35, the protective layer 67 is formed by a region other than the regions corresponding to the arm portions 12A to 12C, the support portion 22 and the buffer portion 23 in the opening of the Si substrate, and the electrode connection portion 63. A lift-off resist film 64 is formed in the region. Thereafter, 50nm of Al 2 O 3 to improve the adhesion, the SiO 2 750 nm high insulating properties, the Al 2 O 3 to improve the resist adhesion during subsequent manufacturing steps in the uppermost layer deposited by 50nm sputtering It was. Then, a so-called lift-off method is used in which the sputtering film adhering to unnecessary portions is removed simultaneously with the removal of the lift-off resist film 64. The formation method and material of the protective layer 67 are arbitrary, and are not limited to the above formation method and material. As a result, as shown in FIGS. 36 and 37, the protective layer 67 is not formed in the region where the lift-off resist film 64 was formed. Therefore, the electrode connection part 63 is in a state where the Au film is exposed. 37 is an enlarged plan view of an electrode formed in a region corresponding to the arm portion of FIG. 36 and a cross-sectional view thereof.
  [Wiring film forming process]
  Next, as shown in FIG. 38, lead wires 133 a, 133 b, 134 a, 134 b, 137 a, 137 b, 137 c, dummy lead wires 138 and external connection terminals 140 to 147 are formed on the protective layer 67. One end of each of the lead wires 133a, 133b, 134a, 134b, 137a, 137b, and 137c and the dummy lead wire 138 is electrically connected to the corresponding electrode by the electrode connecting portion 63.
  In this step, as shown in FIGS. 39 and 40, polarization wirings 65 and 66 are also formed at the same time. 40 is a partially enlarged view of FIG. The vibrator of this embodiment is finally polarized as shown in FIG. 16 or FIG. 18 to stabilize the piezoelectric characteristics, but in order to make the polarization work efficient, the elements in the same row are collectively performed. Yes. In order to perform this simultaneous polarization, wiring on the voltage application side and GND side must be formed in advance. Here, as shown in FIG. 39, the polarization wiring 65 on the GND side, the polarization wiring 66 on the voltage application side, and the like. Is forming. The polarization wiring pattern shown in FIG. 39 is for the case where the piezoelectric polarization directions shown in FIG. 16 are all the same. When forming an element in the piezoelectric polarization direction as shown in FIG. 18, the shape of the polarization wiring 65 may be changed. That is, in FIG. 35, the lower electrode layer 17a and the lower electrode layer 17c, and the lower electrode layer 17c and the lower electrode layer 17b are each formed with the polarization wiring 65 so as to be electrically connected. Polarization wiring may be formed so that the lower electrode layer 17c and the drive electrode 13a, and the lower electrode layer 17c, the lower electrode layer 17b, and the drive electrode 13b are electrically connected.
  The lead wirings 133a, 133b, 134a, 134b, 137a, 137b, and 137c, the dummy lead wiring 138, the external connection terminals 140 to 147, and the polarization wirings 65 and 66 are formed by forming a resist pattern film having a desired shape by photolithography. After the formation, a wiring electrode film was formed by sputtering, and the sputtered film adhering to an unnecessary portion was formed by a so-called lift-off method in which the resist film was removed simultaneously with removal. As a material for the wiring electrode film, after depositing 20 nm of Ti in order to improve adhesion, 300 nm of Cu having low electric resistance and low cost is deposited, and then depositing 500 nm of Au to facilitate bonding with Au bumps. It was. However, the material and forming method of the wiring film are arbitrary, and are not limited to the forming method and material of vapor.
Next, a back stopper film is formed on the thermal oxide film 162b of the Si substrate 161. The purpose is to prevent edge shape defects due to plasma concentration on the lowermost surface when through etching is performed in forming an arm portion described later. In this embodiment, SiO 2 is formed on the entire back surface by sputtering to 500 nm.
  [Arm part and constriction part forming process]
  Next, as shown in FIG. 41, the arm portion and the constricted portion space are removed to form a vibrator. The method of forming the arm portion and the constricted portion space is to form a resist pattern film having the through portion 66 as an opening portion by photolithography, remove the thermal oxide film 162a by ion etching, and then etch until penetrating the Si substrate 161. To do. The removal of the thermal oxide film 162a can be performed by wet etching, but ion etching is preferable in consideration of a dimensional error due to side etching.
  In order to penetrate Si of the Si substrate 161, in this embodiment, the arm portion thickness (diaphragm thickness t11) is 100 μm, and this amount needs to be removed by etching. In normal ion etching or the like, the selectivity with the resist film cannot be obtained, and it is difficult to leave it as a vertical wall surface. In the present embodiment, a Bosch process (SF6 during etching, C4F8 gas during film formation) that repeats etching and sidewall protective film formation is used in an apparatus equipped with ICP (Inductively Coupled Plasma) to achieve vertical operation. An arm portion having a side wall surface was formed. A technique for grinding the Si material vertically is generally established, and this embodiment is also performed by a commercially available apparatus. However, the method for removing the arm space is arbitrary, and is not limited to the above method.
  After the etching with ICP is completed, the back stopper film is removed. In this embodiment, it was removed by wet etching with ammonium fluoride.
  [Polarization process]
  Next, a polarization process is performed to stabilize the piezoelectric characteristics. In order to collectively polarize the elements in the same row, they are connected to an external power source via the application side pad and the GND side pad. In this embodiment, the polarization process is performed at a temperature equal to or higher than the reflow temperature. As a result, the piezoelectric characteristics of the three arm portions can be made uniform, torsional vibration can be eliminated, and the characteristics can be stabilized.
  [Gold bump formation]
  Next, Au bumps 50 are formed on the eight external connection terminals in order to perform flip chip.
  [Cutting process]
  Next, as shown in FIG. 42, the plurality of angular velocity sensors 1 formed on the Si substrate 161 are individually divided.
  [Mounting process]
  Then, the angular velocity sensors 1 that are individually divided are mounted on a mounting substrate 160 such as an IC substrate by a flip chip technique, for example, as shown in FIG. The mounting board 160 is designed in advance so that the electrical connection is completed in accordance with the arrangement of the angular velocity sensor 1. In the example of FIG. 20, the two angular velocity sensors 150 including the two angular velocity sensors 1 are formed by mounting the angular velocity sensors 1 one by one in the x direction and the y direction.
  Next, an electronic apparatus provided with the biaxial angular velocity sensor 150 will be described.
  FIG. 43 is a schematic perspective view showing a digital camera as an example of an electronic apparatus on which the biaxial angular velocity sensor 150 is mounted. FIG. 44 is a block diagram showing the configuration of the digital camera.
  The digital camera 260 includes a device main body 261 on which the biaxial angular velocity sensor 150 is mounted. The device main body 261 is, for example, a metal or resin frame or housing.
  As shown in FIG. 43, the digital camera 60 includes a vibration type gyro sensor 150, a control unit 510, an optical system 520 including a lens, and a camera shake correction mechanism 540 that performs camera shake correction on the CCD 530 and the optical system 520. And have.
  The biaxial Coriolis force is detected by the vibration type gyro sensor 150. Based on the detected Coriolis force, control unit 510 corrects camera shake with optical system 520 using camera shake correction mechanism 540.
  The electronic device on which the vibration gyro sensor according to each of the above embodiments is mounted is not limited to the digital camera described above. For example, examples of the electronic device include a laptop computer, a PDA (Personal Digital Assistance), an electronic dictionary, an audio / visual device, a projector, a mobile phone, a game device, a car navigation device, a robot device, and other electrical appliances. It is done.
It is the bottom view and side view which show schematic structure of the angular velocity sensor which concerns on embodiment of this invention. FIG. 2 is a sectional view taken along line 2-2 in FIG. 1. It is a block diagram which shows the structure of the drive detection circuit of the angular velocity sensor shown in FIG. It is sectional drawing which shows schematic structure of the state by which the angular velocity sensor shown in FIG. 1 was mounted in the mounting board | substrate. It is a figure which shows the relationship between the thickness b of a fixing | fixed part, and the vibration amount of a mounting board | substrate. It is a figure which shows the relationship between the length c and the thickness b of a fixing | fixed part from which the vibration amount of a mounting board | substrate is 5 nm or less and proximity noise is 20 mV or less. It is a schematic plan view for demonstrating the shape of the detection electrode of the angular velocity sensor 1 shown in FIG. 1, a reference electrode, a drive electrode, and the lead wiring electrically connected to these. It is a figure showing the relationship between the area ratio of the lead wiring connected to a right-and-left detection electrode, and leakage current. It is a figure showing the relationship between the area ratio of the lead wiring connected to a right-and-left detection electrode, and a right-and-left leak current difference. It is a figure showing the relationship between right-and-left leakage current difference and Null. It is a figure showing the relationship between Null and PSRR. It is a figure showing the relationship between the area ratio of the lead wiring connected to each of the right and left detection electrodes, and PSRR. It is a figure showing the relationship between the area ratio of the lead wiring connected to each of the left and right drive electrodes, and PSRR. It is a schematic plan view for demonstrating the shape of the lower electrode layer of the angular velocity sensor shown in FIG. 1, and the lead wiring electrically connected to this. It is a figure which shows the result of having measured PSRR with the case where dummy lead wiring is provided and the case where it does not exist. It is a figure which shows the wiring state of the angular velocity sensor. It is sectional drawing cut | disconnected by line 17-17 of FIG. It is a figure which shows the wiring state of an angular velocity sensor. It is sectional drawing cut | disconnected by the line 18-18. It is a top view which shows the state in which the angular velocity sensor was mounted in the mounting board | substrate. It is a figure which shows the relationship between the distance between arm terminals (arm space | interval), and responsiveness. It is a figure which shows the relationship between an arm space | interval and Q value. It is a figure which shows the relationship between the arm space | interval at the time of varying the cross-sectional area of an arm part, and Q value. It is a figure which shows the relationship between the arm space | interval at the time of varying the length of an arm part, and Q value. It is a main process flow explaining the manufacturing method of an angular velocity sensor. It is a figure for demonstrating a board | substrate preparation process. It is FIG. (1) for demonstrating a diaphragm formation process. It is FIG. (2) for demonstrating a diaphragm formation process. It is FIG. (3) for demonstrating a diaphragm formation process. It is FIG. (4) for demonstrating a diaphragm formation process. It is a figure for demonstrating an electrode film formation process. It is FIG. (1) for demonstrating an electrode film processing process. It is FIG. (2) for demonstrating an electrode film processing process. It is FIG. (3) for demonstrating an electrode film processing process. It is FIG. (1) for demonstrating a protective layer formation process. It is FIG. (2) for demonstrating a protective layer formation process. FIG. 37 is an enlarged plan view of an electrode formed in a region corresponding to the arm portion of FIG. 36 and a cross-sectional view thereof. It is FIG. (1) for demonstrating a wiring film formation process. It is FIG. (2) for demonstrating a wiring film formation process. It is the elements on larger scale of FIG. It is a figure for demonstrating an arm part and a constriction part formation process. It is a figure for demonstrating a cutting process. It is a schematic perspective view of the digital camera as an example of the electronic device provided with the angular velocity sensor shown in FIG. FIG. 44 is a block diagram illustrating a configuration of the digital camera illustrated in FIG. 43.
Explanation of symbols
  DESCRIPTION OF SYMBOLS 1 ... Angular velocity sensor, 1A ... Mounting surface, 12A-12C ... Arm part, 13a, 13b ... Drive electrode, 14a, 14b ... Detection electrode, 15A-15C ... Piezoelectric functional layer , 16a to 16c ... lower electrode layer, 17a to 17c ... piezoelectric layer, 22 ... support part, 23 ... buffer part, 24 ... fixing part, 140-147 ... external connection terminal 133a, 133b, 133c, 134a, 134b, 137a, 137b, 137c ... lead wiring, 138 ... dummy lead wiring, 260 ... digital camera

Claims (6)

  1. A support part;
    An arm portion having three piezoelectric functional layers extending from the support portion and disposed along one direction;
    A fixing portion having a mounting surface provided with terminals electrically connected to the piezoelectric functional layer;
    A buffer portion disposed between the support portion and the fixed portion and coupled to the support portion and the fixed portion;
    The angular velocity sensor according to claim 1, wherein a width of the buffer portion along the one direction is narrower than a width of the fixed portion and the support portion along the one direction.
  2.   The angular velocity sensor according to claim 1, wherein a thickness of the fixing portion along a direction orthogonal to the mounting surface is larger than thicknesses of the arm portion, the support portion, and the buffer portion.
  3.   The angular velocity sensor according to claim 1, wherein the wiring connecting the piezoelectric functional layer and the terminal has a line-symmetric shape.
  4. The base,
    Three arms integrally extending from the base in substantially the same direction;
    A lower electrode layer formed on the arm,
    A piezoelectric layer formed on the lower electrode layer formed on the arm portion;
    Drive electrodes formed on the piezoelectric layers of at least two arm portions located outside of the three arm portions;
    A detection electrode for detecting an angular velocity formed on the piezoelectric layer of the arm portion located at least in the center of the three arm portions;
    A wiring electrically connected to each of the lower electrode layer, the piezoelectric layer, the drive electrode, and the detection electrode;
    An angular velocity sensor characterized in that the wiring is arranged in a line-symmetric shape.
  5. Mounting surface provided with a support portion, an arm portion having three piezoelectric functional layers extending from the support portion and disposed along one direction, and a terminal electrically connected to the piezoelectric functional layer And a buffer part that is disposed between the support part and the fixed part and is coupled to the support part and the fixed part, and the width of the buffer part along the one direction is An angular velocity sensor narrower than the width along the one direction of each of the fixed portion and the support portion;
    An electronic device comprising: a device main body on which the angular velocity sensor is mounted.
  6. A base, three arm portions integrally extending from the base in substantially the same direction, a lower electrode layer formed on the arm portion, and formed on the lower electrode layer formed on the arm portion A piezoelectric layer formed on the piezoelectric layer of at least two of the three arm portions, and at least the center of the three arm portions. A detection electrode for detecting an angular velocity formed on the piezoelectric layer of the arm portion; and a wiring electrically connected to each of the lower electrode layer, the piezoelectric layer, the drive electrode, and the detection electrode. An angular velocity sensor arranged in
    An electronic device comprising: a device main body on which the angular velocity sensor is mounted.
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