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WO2017183646A1 - Capteur composite - Google Patents

Capteur composite Download PDF

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Publication number
WO2017183646A1
WO2017183646A1 PCT/JP2017/015646 JP2017015646W WO2017183646A1 WO 2017183646 A1 WO2017183646 A1 WO 2017183646A1 JP 2017015646 W JP2017015646 W JP 2017015646W WO 2017183646 A1 WO2017183646 A1 WO 2017183646A1
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WO
WIPO (PCT)
Prior art keywords
electrode
angular velocity
plate
acceleration
sensor
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Ceased
Application number
PCT/JP2017/015646
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English (en)
Japanese (ja)
Inventor
藤井　隆満
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Fujifilm Corp
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Fujifilm Corp
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Application filed by Fujifilm Corp filed Critical Fujifilm Corp
Priority to JP2018513191A priority Critical patent/JP6594527B2/ja
Publication of WO2017183646A1 publication Critical patent/WO2017183646A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C19/00—Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
    • G01C19/56—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
    • G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
    • G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
    • G01P15/125—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by capacitive pick-up
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/18—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration in two or more dimensions
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
    • H10D48/00—Individual devices not covered by groups H10D1/00 - H10D44/00
    • H10D48/50—Devices controlled by mechanical forces, e.g. pressure
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/20—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/30—Piezoelectric or electrostrictive devices with mechanical input and electrical output, e.g. functioning as generators or sensors
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/80—Constructional details
    • H10N30/87—Electrodes or interconnections, e.g. leads or terminals

Definitions

  • the present invention relates to a composite sensor that detects angular velocity and acceleration.
  • Angular velocity sensors and acceleration sensors are used for attitude control and navigation of electronic devices such as game machines, portable information terminals, digital cameras, automobiles, airplanes, and ships.
  • Sensors that detect physical quantities such as angular velocity and acceleration are based on electrostatic systems that detect changes in physical quantities based on the displacement of the capacitance between the fixed electrode and the movable electrode, and on the basis of changes in strain caused by piezoelectric elements. For example, a piezoelectric method for detecting a change in physical quantity is known.
  • Patent Documents 1, 2, and 8 disclose angular velocity sensors using piezoelectric elements.
  • Patent Document 1 and Non-Patent Document 1 disclose that six axes (acceleration three axes, angular velocity three axes) can be measured using a piezoelectric element.
  • a piezoelectric sensor cannot detect a static acceleration such as a gravitational acceleration because of the principle of detecting a charge generated by a change in stress. Even if the acceleration is dynamic, it may not be detected if the movement (change) is very slow (for example, 1 Hz or less).
  • the composite sensors described in Patent Documents 5 and 6 are a combination of a piezoelectric sensor for measuring angular velocity and a piezoresistive acceleration sensor, which can be realized in a small size without increasing the size, and can also measure static acceleration. is there.
  • a piezoresistive acceleration sensor for measuring angular velocity
  • a piezoresistive acceleration sensor for measuring static acceleration.
  • the composite sensor described in Patent Document 7 is an integrated angular velocity sensor using a piezoelectric method and an acceleration sensor using an electrostatic method. It cannot be realized, and the size may increase.
  • an object of the present invention is to provide a composite sensor capable of detecting static acceleration in addition to angular velocity, which can be easily manufactured and can be downsized.
  • the composite sensor of the present invention calculates the angular velocity by detecting the weight portion, the vibration excitation portion that induces vibration in the direction of the predetermined vibration axis with respect to the weight portion, and the displacement of the weight portion caused by the Coriolis force.
  • An angular velocity sensor comprising: a vibration excitation unit and an angular velocity detection unit each comprising a piezoelectric element comprising a laminate of a lower electrode, a piezoelectric film and an upper electrode provided on one surface of a plate-like substrate.
  • An angular velocity sensor comprising a weight portion configured as a part of a plate-like substrate; Acceleration is calculated by detecting a change in capacitance between the movable electrode provided at a part of the weight part, the fixed electrode provided at a fixed position facing the movable electrode, and the movable electrode and the fixed electrode.
  • An acceleration sensor including an acceleration detection unit.
  • weight portions is not limited to one, and two or more weight portions may be provided.
  • the composite sensor of the present invention preferably includes a housing that includes an angular velocity sensor and an acceleration sensor, and the atmospheric pressure in the housing is preferably less than atmospheric pressure.
  • the fixed electrode is preferably composed of two or more fixed electrode pieces with respect to one weight portion.
  • the distance between the movable electrode and the fixed electrode is less than the distance at which the stress applied to the piezoelectric film due to the displacement of the weight portion in the direction in which the two are close to each other becomes the breaking stress.
  • the fixed electrode is provided on one surface of the sub-plate base material that is a separate member from the plate-type base material, and the movable base electrode and the fixed electrode are not driven. It is preferable that the sub-plate-like base material is joined at a position opposed to each other at a predetermined interval.
  • the said plate-shaped base material and a sub-plate-shaped base material are joined through the spacer.
  • the spacer it is preferable that the spacer has conductivity and has an electrode wiring function.
  • the sub-plate-like substrate has an angular velocity detection control circuit using an angular velocity sensor.
  • the piezoelectric element constituting a part of the angular velocity sensor functions as a part of the dynamic acceleration sensor for detecting the dynamic acceleration.
  • the composite sensor of the present invention includes a piezoelectric angular velocity sensor, a movable electrode provided in a part of a weight portion which is one of the components of the angular velocity sensor, and a fixed position facing the movable electrode.
  • a fixed electrode and an acceleration sensor having an acceleration detection unit that calculates an acceleration by detecting a change in capacitance between the movable electrode and the fixed electrode.
  • the acceleration detection unit generates static acceleration. It is possible to detect.
  • the composite sensor having such a configuration includes a movable electrode for detecting capacitance at a part of the weight portion of the angular velocity sensor, and thus can be miniaturized and easily manufactured.
  • Cut end view of the composite sensor according to the first embodiment of the present invention The figure which shows the upper electrode pattern of the angular velocity sensor of the composite sensor which concerns on embodiment
  • the figure which shows an example of a fixed electrode The figure which shows the manufacturing process of the composite sensor which concerns on 1st Embodiment (the 1)
  • Cut end view of compound sensor of design change example 1 Cut end view of compound sensor of design change example 2 Cut end view of the composite sensor according to the second embodiment of the present invention
  • FIG. 1 is a schematic cut end view of a composite sensor 1 according to an embodiment of the present invention.
  • the composite sensor 1 of the present embodiment includes a plate-like base material 10 in which a weight portion 15 and piezoelectric elements 25 and 26 are formed, and a fixed electrode 45 facing a movable electrode 35 provided in a part of the weight portion 15.
  • the sub-plate-like base material 40 provided, and the casing 50 in which the plate-like base material 10 and the sub-plate-like base material 40 are contained are provided.
  • the plate-like base material 10 includes a weight portion 15 formed by deeply digging the periphery on one surface side.
  • a region (deep digging region) in which a part of the plate-like base material 10 is deeply dug to reduce the thickness (deep digging region) uses a part having the original thickness of the plate-like base material 10 around the deep digging region as a support portion. It constitutes a diaphragm. That is, the plate-like base material 10 is provided with a diaphragm, and the weight portion 15 is provided in the approximate center of the diaphragm.
  • a plurality of piezoelectric elements 25 and 26 are provided in which a lower electrode 21, a piezoelectric film 22, and upper electrodes 24 ⁇ / b> A and 24 ⁇ / b> B are sequentially stacked.
  • the lower electrode 21 and the piezoelectric film 22 are formed in a continuous film shape over almost the entire area on the other surface side, and the upper electrodes 24A and 24B provided on the piezoelectric film 22 are patterned to form individual piezoelectric elements.
  • Elements 25 and 26 are defined.
  • “lower” and “upper” do not mean top and bottom.
  • one electrode disposed on the plate-like substrate 10 side is simply referred to as a lower electrode, and the other electrode is referred to as an upper electrode.
  • FIG. 2 is a schematic plan view showing a pattern example of the upper electrodes 24A and 24B.
  • four upper electrodes 24A that define the piezoelectric element 25 for vibration excitation and four upper electrodes 24B that define the piezoelectric element 26 for angular velocity detection are provided.
  • the upper electrode 24A is formed across the boundary between the outer peripheral edge of the diaphragm and the support portion, and the upper electrode 24B is formed across the boundary between the outer peripheral edge of the weight portion 15 and the deep digging region.
  • the piezoelectric element 25 constitutes a part of the vibration excitation unit
  • the piezoelectric element 26 constitutes a part of the angular velocity detection unit that detects the displacement of the weight 15 caused by the Coriolis force and calculates the angular velocity.
  • the four piezoelectric elements 25 are driven to give a desired vibration to the diaphragm, thereby inducing a vibration in the direction of the predetermined vibration axis in the weight portion 15.
  • the piezoelectric film 22 is distorted in accordance with the displacement of the weight portion caused by the Coriolis force received by the vibrating weight portion 15, and the electric speed generated by the strain is detected by the piezoelectric element 26 to obtain the angular velocity.
  • the piezoelectric element 25 formed of a laminate of the lower electrode 21, the piezoelectric film 22, and the upper electrode 24A provided on the diaphragm including the weight portion 15 and the weight portion 15 formed on the plate-like substrate 10 functions as a piezoelectric actuator.
  • the piezoelectric element 26 composed of a laminate of the lower electrode 21, the piezoelectric film 22 and the upper electrode 24B functions as a piezoelectric sensor, and the piezoelectric element 25 and the piezoelectric element 26 constitute a part of the angular velocity sensor.
  • a driving control for driving the piezoelectric element 25 and a calculation unit for obtaining acceleration based on the current value detected by the piezoelectric element 26 are provided in an angular velocity detection control circuit described later.
  • the angular velocity sensor of this configuration defines an XYZ three-dimensional orthogonal coordinate system having an origin O at the center position of the diaphragm, an XY plane including the surface of the diaphragm, and Z as a direction perpendicular thereto.
  • One of the X axis and the Z axis is set as a vibration axis, and the other is set as a displacement axis, and an angular velocity around the Y axis is detected based on a detection value from an angular velocity detection electrode constituting the displacement detector.
  • the weight portion may be vibrated in the Z-axis direction and the displacement in the Y-axis direction and the X-axis direction may be detected. Further, in order to detect the angular velocity around the Z axis, the weight portion may be vibrated in the X axis direction or the Y axis direction, and the displacement in the Y axis direction or the X axis direction may be detected.
  • the configuration of the diaphragm and the electrode of the angular velocity sensor is an example, and for example, the one described in Patent Document 2 (Japanese Patent Laid-Open No. 2014-66708) described above is applied in order to improve the accuracy as the angular velocity sensor. Also good. Furthermore, a structure such as that disclosed in Patent Document 8 (Japanese Patent Laid-Open No. 2013-217872) may be used.
  • An electrode film 32 is uniformly formed on the surface side of the plate-like substrate 10 on which the weight portion 15 is provided via the adhesion layer 31.
  • a portion of the electrode film 32 provided on the lower end surface in the drawing of the weight portion 15 functions as the movable electrode 35.
  • the electrode film 32 is provided on the entire surface of the plate-like substrate 10 on the weight portion 15 side, but it is sufficient that it is provided at least on the lower end surface of the weight portion 15. In this configuration, the movable electrode 35 is set to the ground potential.
  • a fixed electrode 45 is provided on one surface of the sub-plate-like base material 40 prepared as a separate member from the plate-like base material 10, and the plate-like base material 10 includes the movable electrode 35 and the fixed electrode 45 of the weight portion 15. Are bonded (adhered) to the sub-plate-like base material 40 in a state of being opposed to each other. Further, the plate-like substrate 10 and the sub-plate-like substrate 40 are set so that the distance d between the movable electrode 35 and the fixed electrode 45 is a predetermined distance when the sensor 1 is not driven (when not driven).
  • a spacer 48 is provided as an interval maintaining mechanism defined in FIG. The spacer 48 preferably has an adhesion function and a spacing maintaining function. For example, a mixture of Au-Sn metal material for eutectic bonding with glass beads that do not change in shape to maintain the spacing d is used. Can do.
  • the capacitance between both electrodes changes.
  • a change in the relative position of the movable electrode 35 with respect to the fixed electrode 45 is detected by detecting a change in capacitance, thereby obtaining an acceleration. That is, the movable electrode 35 provided on the weight portion 15 and the fixed electrode 45 provided on the sub-plate base material 40 constitute a part of the acceleration sensor.
  • a calculation unit for obtaining acceleration from a change in capacitance between the movable electrode 35 and the fixed electrode 45 is provided in an acceleration detection control circuit described later. According to the acceleration sensor of this configuration, static acceleration can be detected.
  • FIG. 3 is a schematic diagram showing an example of the configuration of the fixed electrode 45.
  • the fixed electrode 45 provided for one weight part 15 which is movable electrode 35 is obtained with the four fixed electrode pieces 45x 1, 45x 2, 45y 1 , 45y 2 .
  • the fixed electrode 45 should just be comprised from two or more fixed electrode pieces, it is more preferable that it is four or more.
  • each of the electrostatic capacitance between the detecting a change in capacitance, the 45x movable electrode 35 and the individual fixed electrode pieces 1, 45x 2, 45y 1, 45y 2 between the fixed electrode 45 and movable electrode 35 It means detecting a change in Cx 1 , Cx 2 , Cy 1 , Cy 2 , or a change in their capacitance ratio.
  • the sensor 1, the inclination of the X direction or Y direction, the output Y 1 and Y from the output X 1 and X 2 or the fixed electrode pieces 45y 1, 45y 2, from the fixed electrode pieces 45x 1, 45x 2 in FIG. 3 2 can be detected.
  • Each absolute value can be measured in advance by reference measurement. For example, as a reference measurement, absolute acceleration is obtained by applying a known acceleration to the sensor in advance, measuring the capacitance at that time, graphing the relationship between acceleration and capacitance, and correcting based on the data. The value can be determined.
  • the distance d between the movable electrode 35 and the fixed electrode 45 provided on the sub-plate-like substrate 40 increases, Since the capacitance becomes smaller and the change in capacitance becomes minute, the distance d between the movable electrode 35 and the fixed electrode 45 should be as narrow as possible.
  • the distance d needs to be made larger than the amplitude necessary for angular velocity sensing because it is necessary to vibrate the weight portion 15 in the Z direction for sensing angular velocity. If air exists around the weight 15, the movement may be suppressed due to the air damping effect. Therefore, it is preferable to reduce the air pressure by removing the air around the weight 15. Therefore, the atmospheric pressure inside the housing 50 is preferably at least less than atmospheric pressure (1 atm), and the smaller the degree of vacuum, the better.
  • the measurement sensitivity can be increased to some extent by a device on the circuit side.
  • a circuit device As a circuit device, a bridge circuit, a comparison and ratio of capacitance between electrodes, and the like can be considered.
  • the piezoelectric film 22 is configured not to be applied with a stress greater than the fracture stress. That is, the distance d between the movable electrode 35 and the fixed electrode 45 is such that the stress applied to the piezoelectric film 22 by the displacement of the weight portion 15 in the direction in which they are close to each other (that is, the Z-axis direction in this example) is the fracture stress.
  • the fixed electrode 45 side is made to function as a stopper that limits the amount of movement of the weight portion 15.
  • the distance d between the movable electrode 35 and the fixed electrode 45 in a stationary state where the composite sensor 1 is not driven is preferably, for example, about 15 ⁇ m or less and about 0.5 ⁇ m or more, for example, 1 ⁇ m.
  • the preferable distance d needs to be appropriately determined according to the size of the weight portion 15, the size of the diaphragm, the thickness of the piezoelectric film, and the like.
  • the interval d is set so that a stress of 200 MPa or more is not applied to the piezoelectric film.
  • the breaking stress varies depending on the material and thickness of the piezoelectric film, and can be measured by, for example, a cantilever structure in which a piezoelectric film formed on an Si substrate via an electrode is formed with an upper electrode. That is, an alternating voltage is applied between the upper and lower electrodes of the piezoelectric film having a cantilever structure to drive resonance, and the cantilever is displaced greatly by applying a drive voltage. Increasing the driving voltage increases the displacement and structurally breaks the piezoelectric film. Fracture stress can be calculated from the displacement at that time by FEM (Finite Element Method) or the like.
  • FEM Finite Element Method
  • the acceleration sensor with the above configuration can detect not only static acceleration but also dynamic acceleration. Since the amount of displacement differs greatly between detection of dynamic acceleration and detection of static acceleration, two dynamic ranges are prepared on the detection circuit side, and the dynamic range is switched and detected at a predetermined threshold. It is preferable.
  • the acceleration sensor has only one dynamic range on the detection side, the acceleration sensor is used to detect static acceleration or very slow dynamic acceleration, and the angular velocity sensor also serves as the dynamic acceleration sensor.
  • Patent Document 1 Japanese Patent Laid-Open No. 2006-23320 described above.
  • the sub-plate-like base material 40 is preferably provided with an ASIC (Application specific integrated circuit).
  • the ASIC includes an angular velocity detection control circuit for the angular velocity sensor and an acceleration detection control circuit for the acceleration sensor.
  • the spacer 48 in contact with the electrode film 32 having the same electric potential as that of the movable electrode 35 is used to electrically connect the movable electrode 35 to the circuit of the sub-plate-like substrate 40 or to the outside. Therefore, it is preferable to have conductivity and have an electrode wiring function.
  • the plate-like base material 10 and the sub-plate-like base material 40 it is preferable to use a Si wafer, a SOI (silicon ion insulator) wafer, or the like because it is easy to process.
  • a Si wafer As the plate-like base material 10 and the sub-plate-like base material 40, it is preferable to use a Si wafer, a SOI (silicon ion insulator) wafer, or the like because it is easy to process.
  • SOI silicon ion insulator
  • the material of the lower electrode 21 is not particularly limited, and may be a metal or an oxide conductor material. Specifically, Pt (platinum), Al (aluminum), Mo (molybdenum), TiN (titanium nitride), Ru (ruthenium), Au (gold), silver (Ag), Ir (iridium), ITO (indium tin) A material such as an oxide) can be used. Further, Ti, TiW, or the like may be provided between the Si active layer 13 and the lower electrode 21 as an adhesion layer for improving the adhesion with the Si active layer 13.
  • the thickness of the lower electrode 21 can be designed to an appropriate thickness, but is preferably 50 to 500 nm. If the lower electrode 21 is too thick, the rigidity is increased and the displacement of the piezoelectric film 22 may be restricted. Therefore, the thickness is more preferably 50 to 300 nm.
  • the piezoelectric film 22 there is no restriction
  • the piezoelectric film 22 for example, one or more perovskite oxides represented by the following general formula (P) can be used, and the substrate temperature is raised by a vapor deposition method typified by a sputtering method. It can be formed by a method of crystallizing during film formation (preferably at 400 ° C. or higher).
  • ABO 3 (P) (In the formula, A is an A site element and at least one element including Pb, B is an element of a B site, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Mn, Sc, At least one element selected from the group consisting of Co, Cu, In, Sn, Ga, Zn, Cd, Fe, Ni, and a lanthanide element, O: oxygen atom, and a molar ratio of A: B: O is 1: 1: 3 is the standard, but this molar ratio may deviate within a range where a perovskite structure can be taken.)
  • the Nb-PZT film exhibits spontaneous polarization immediately after deposition (as-deposited state) and does not require polarization processing.
  • the film thickness of the piezoelectric film 22 is preferably 0.3 ⁇ m or more and 10 ⁇ m or less, more preferably 0.5 ⁇ m or more and 8 ⁇ m or less, and further preferably 1 ⁇ m or more and 7 ⁇ m or less. If the thickness is 0.3 ⁇ m or more, a sufficient driving force as an actuator can be generated, and a sufficient voltage signal as a sensor or a power generation device can be extracted.
  • the manufacturing process of the composite sensor of the said embodiment is demonstrated.
  • the plate-like base material 10 is prepared.
  • an SOI wafer (hereinafter referred to as “Si wafer 11”) composed of a Si substrate 11, a BOX (Buried Oxide) layer 12 made of SiO 2 , and a Si active layer 13 facing the Si substrate 11 across the BOX layer 12.
  • Si wafer 11 an SOI wafer
  • a lower electrode 21 is formed on the surface of the Si active layer 13 of the SOI wafer 10
  • a piezoelectric film 22 is formed on the lower electrode 21 (step S1 in FIG. 4).
  • the specification of the SOI wafer 10 is preferably a specification suitable for an angular velocity sensor.
  • the thickness of the BOX layer 12 is preferably 0.3 to 1.0 ⁇ m, and the thickness of the Si active layer 13 is preferably 3 to 50 ⁇ m.
  • these specifications can be appropriately selected depending on the structure of the sensor.
  • the lower electrode and the piezoelectric film can be formed by a known thin film forming method.
  • Thin film formation methods include physical vapor deposition (PVD), chemical vapor deposition (CVD), and liquid deposition (plating, coating, sol-gel, spin Coating method) and thermal oxidation method.
  • PVD physical vapor deposition
  • CVD chemical vapor deposition
  • liquid deposition plating, coating, sol-gel, spin Coating method
  • thermal oxidation method thermal oxidation method.
  • an appropriate film formation method can be selected for each layer, a structure in which all layers are formed by vapor deposition is most preferable.
  • the vapor phase growth method can control the thickness dimension with high accuracy.
  • the material is inexpensive, the film formation rate is high, and it is suitable for mass production, the cost of the device can be reduced.
  • the method for forming the piezoelectric film is not limited to the sputtering method, and various methods such as an ion plating method, an MOCVD method (metal organic chemical vapor deposition method), and a PLD method (pulse laser deposition method) can be applied. It is also conceivable to use a method other than vapor phase growth (for example, a sol-gel method).
  • the manufacturing process can be simplified by forming the piezoelectric film directly on the substrate by sputtering and reducing the thickness of the piezoelectric film.
  • an upper electrode layer is formed on the piezoelectric film 22, and then the upper electrode layer is formed into individual upper electrodes 24A and 24B and wirings in order to form a piezoelectric element that functions as a piezoelectric actuator and a piezoelectric sensor at a desired position. Is patterned (step S2 in FIG. 4). Further, by etching a part of the piezoelectric film 22, the lower electrode 21 is exposed and can be connected to the control circuit.
  • the Si base material 11 is etched from the surface of the SOI wafer 10 on the Si base material 11 side to the BOX layer 12 in a deep digging process to produce the weight portion 15 (step S3 in FIG. 4).
  • a Ti adhesion layer is formed on the entire surface of the SOI wafer on the Si substrate 11 side by sputtering, and an Au electrode is formed thereon (step S4 in FIG. 4).
  • the Au electrode portion on the lower surface of the weight portion 15 in the drawing is a portion that functions as the movable electrode 35 for detecting capacitance, and is set to the ground potential. Since the surface on the weight portion 15 side has large irregularities formed in the deep digging process, in order to form an electrode film uniformly on this surface, for example, sputtering rather than vapor deposition is used, and CVD using sputtering is used. The method is preferable because of its good coverage.
  • a sub-plate-like base material 40 that is prepared separately and on which the fixed electrode 45 for acceleration sensor is formed by patterning is prepared (step S5 in FIG. 5).
  • the sub-plate base material 40 for example, a Si wafer is suitable.
  • the sub-plate-like substrate 40 preferably has an ASIC function for driving and processing the sensor.
  • the weight 15, the piezoelectric element, and the SOI wafer 10 in which the movable electrode is incorporated and the sub-plate-like base material 40 are opposed to the movable electrode 35 of the weight portion 15 facing the fixed electrode 45 on the sub-plate-like base material 40. Then, they are positioned and bonded together (step S6 in FIG. 5).
  • bonding eutectic bonding, bonding with Au particles, bonding with an epoxy resin, or the like can be used.
  • Au—Sn metal is formed on a 1 ⁇ m edge portion, and can be bonded by heating and pressing. Since it is important to control the gap between the movable electrode 35 and the fixed electrode 45 at the time of bonding, glass beads that function as the spacers 48 may be mixed in the bonding material.
  • the composite sensor 1 shown in FIG. 1 can be manufactured by sealing in the housing 50 under a reduced pressure atmosphere.
  • the composite sensor 1 includes the movable electrode 35 on a part of the weight portion 15 which is one of the components of the angular velocity sensor, and the movable electrode 35 is provided to face the movable electrode 35.
  • an acceleration sensor that includes an acceleration detection unit that detects the change in capacitance with the fixed electrode 45 and calculates the acceleration, static acceleration can be detected with a small configuration. It has become.
  • the composite sensor 1 since the composite sensor 1 has a simple configuration, it can be easily manufactured.
  • the spacer 48 is provided as a gap maintaining mechanism for controlling the gap between the movable electrode 35 and the fixed electrode 45.
  • the mechanism for maintaining the gap is provided here.
  • 6 and 7 show cut end views of the composite sensor 1A of the design change example 1 and the composite sensor 1B of the design change example 2, respectively.
  • the adhesion layer 31 and the electrode film 32 to be connected to the sub-plate-like substrate 40 on the plate-like substrate 10 side are removed, and the plate-like substrate is obtained using the Si wafer direct bonding technique.
  • the material 10 and the sub-plate-like substrate 40 can be directly joined. According to such a configuration, it is possible to improve the interval adjustment accuracy as compared with the case where an adhesive is used, and it is possible to increase the bonding strength.
  • FIG. 8 is a cut end view of the composite sensor 2 according to the second embodiment.
  • the plate-like base material 10 in the composite sensor 2 of the first embodiment is arranged opposite to the top and bottom.
  • the same components as those of the composite sensor 2 of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
  • a movable electrode 24C (35) is provided on a part of the weight portion 15 on the diaphragm side.
  • FIG. 9 shows an upper electrode pattern on one surface of the plate-like substrate 10.
  • a movable electrode 24C is provided at the center of the upper electrodes 24A and 24B. The movable electrode 24C can be patterned simultaneously with the upper electrodes 24A and 24B.
  • the manufacturing process can be simplified as compared with the case where the movable electrode 35 is provided on the lower end side of the weight portion 15. Further, in this configuration, either the movable electrode 24C or the fixed electrode 45 may be a ground potential.
  • the detection method of angular velocity and acceleration in the composite sensor 2 of the present embodiment is the same as that of the composite sensor 1 of the first embodiment. According to the composite sensor 2, the same effect of downsizing as the composite sensor 1 can be achieved, and the manufacture can be further facilitated.
  • an angular velocity sensor capable of detecting a three-axis angular velocity with a single weight portion (movable portion) having a weight portion provided at the center of the diaphragm.
  • the movable part of the angular velocity sensor provided may be of other shapes such as a tuning fork type and a butterfly type used in known angular velocity sensors.
  • the number of movable parts is not limited to one, and a plurality of movable parts may be provided. If a movable electrode is provided on a part of the movable part and a fixed electrode is arranged opposite to the movable electrode, It is possible to configure an acceleration sensor that can detect a simple acceleration.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Gyroscopes (AREA)
  • Pressure Sensors (AREA)

Abstract

Le problème décrit par l'invention est de fournir un capteur composite qui est apte à détecter une accélération statique en plus d'une vitesse angulaire et qui peut être facilement fabriqué tout en permettant une mise en œuvre compacte. La solution selon la présente invention concerne un capteur composite (1) comprenant : un capteur de vitesse angulaire comprenant un poids (15) configuré en tant que partie d'un substrat en forme de plaque (10), une section d'excitation par vibration qui induit une vibration dans le poids (15) dans la direction d'un axe de vibration prédéterminé, et une section de détection de vitesse angulaire qui calcule une vitesse angulaire par détection d'un déplacement du poids (15), qui se produit en résultat de la réception d'une force de Coriolis, la section d'excitation par vibration et la section de détection de vitesse angulaire comprenant respectivement des éléments piézoélectriques (25), (26) formés de corps stratifiés d'une électrode inférieure (21), d'un film piézoélectrique (22), et d'électrodes supérieures (24A), (24B) disposés sur une face du substrat en forme de plaque (10) ; et un capteur d'accélération comprenant une électrode mobile (35) disposé sur une partie du poids (15), une électrode fixe (45) étant disposée de manière à faire face à l'électrode mobile (35), et une section de détection d'accélération qui calcule une accélération par détection d'un changement de la capacité électrostatique entre ces électrodes (35), (45).
PCT/JP2017/015646 2016-04-21 2017-04-19 Capteur composite Ceased WO2017183646A1 (fr)

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JP2016-084895 2016-04-21

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Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0868636A (ja) * 1994-08-26 1996-03-12 Kazuhiro Okada 加速度と角速度との双方を検出する装置
JP2003050248A (ja) * 2001-08-08 2003-02-21 Akashi Corp 検出装置
JP2003263853A (ja) * 2003-04-11 2003-09-19 Tokyo Electron Ltd ハードディスク装置
JP2003344438A (ja) * 2002-05-24 2003-12-03 Matsushita Electric Ind Co Ltd 衝撃センサ
JP2007194611A (ja) * 2005-12-22 2007-08-02 Seiko Instruments Inc 三次元配線及びその製造方法、力学量センサ及びその製造方法
JP2010025840A (ja) * 2008-07-23 2010-02-04 Wacoh Corp 力検出装置
JP2011191318A (ja) * 2011-05-30 2011-09-29 Wacoh Corp 角速度センサ
JP2011247768A (ja) * 2010-05-27 2011-12-08 Seiko Epson Corp 素子構造体、慣性センサーおよび電子機器
US20130133426A1 (en) * 2011-11-28 2013-05-30 Samsung Electron-Mechanics Co., Ltd. Inertial sensor
US20130167640A1 (en) * 2011-12-29 2013-07-04 Samsung Electro-Mechanics Co., Ltd. Inertial sensor and method of manufacturing the same
WO2014155997A1 (fr) * 2013-03-29 2014-10-02 旭化成株式会社 Capteur de vitesse angulaire

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0868636A (ja) * 1994-08-26 1996-03-12 Kazuhiro Okada 加速度と角速度との双方を検出する装置
JP2003050248A (ja) * 2001-08-08 2003-02-21 Akashi Corp 検出装置
JP2003344438A (ja) * 2002-05-24 2003-12-03 Matsushita Electric Ind Co Ltd 衝撃センサ
JP2003263853A (ja) * 2003-04-11 2003-09-19 Tokyo Electron Ltd ハードディスク装置
JP2007194611A (ja) * 2005-12-22 2007-08-02 Seiko Instruments Inc 三次元配線及びその製造方法、力学量センサ及びその製造方法
JP2010025840A (ja) * 2008-07-23 2010-02-04 Wacoh Corp 力検出装置
JP2011247768A (ja) * 2010-05-27 2011-12-08 Seiko Epson Corp 素子構造体、慣性センサーおよび電子機器
JP2011191318A (ja) * 2011-05-30 2011-09-29 Wacoh Corp 角速度センサ
US20130133426A1 (en) * 2011-11-28 2013-05-30 Samsung Electron-Mechanics Co., Ltd. Inertial sensor
US20130167640A1 (en) * 2011-12-29 2013-07-04 Samsung Electro-Mechanics Co., Ltd. Inertial sensor and method of manufacturing the same
WO2014155997A1 (fr) * 2013-03-29 2014-10-02 旭化成株式会社 Capteur de vitesse angulaire

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