WO2022113475A1 - Pressure sensor - Google Patents

Pressure sensor Download PDF

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Publication number
WO2022113475A1
WO2022113475A1 PCT/JP2021/033353 JP2021033353W WO2022113475A1 WO 2022113475 A1 WO2022113475 A1 WO 2022113475A1 JP 2021033353 W JP2021033353 W JP 2021033353W WO 2022113475 A1 WO2022113475 A1 WO 2022113475A1
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WO
WIPO (PCT)
Prior art keywords
diaphragm
pressure
pressure information
value
information
Prior art date
Application number
PCT/JP2021/033353
Other languages
French (fr)
Japanese (ja)
Inventor
良平 濱▲崎▼
Original Assignee
株式会社村田製作所
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Publication date
Application filed by 株式会社村田製作所 filed Critical 株式会社村田製作所
Publication of WO2022113475A1 publication Critical patent/WO2022113475A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means

Definitions

  • the present invention relates to a pressure sensor for measuring pressure from the outside.
  • a pressure sensor that measures the pressure acting on the diaphragm based on the displacement of the diaphragm is known.
  • Some pressure sensors include a diaphragm for low pressure and a diaphragm for high pressure (see, for example, Patent Document 1).
  • the diaphragm for high pressure is thicker than the diaphragm for low pressure. Further, in the pressure sensor disclosed in Patent Document 1, a protrusion is provided on the diaphragm for low pressure. As a result, when a high pressure is applied to the pressure sensor, the protrusions come into contact with the substrate. As a result, the low pressure diaphragm thinner than the high pressure diaphragm is prevented from being excessively displaced and damaged.
  • the diaphragm for high pressure and the diaphragm for low pressure are formed on the same silicon plate. Therefore, in the manufacturing process of the pressure sensor, in order to make the diaphragm for high pressure thicker than the diaphragm for low pressure, a complicated process of providing portions having different thicknesses on the same silicon plate is required.
  • an object of the present invention is to solve the above-mentioned problems, and to provide a pressure sensor capable of avoiding complicated manufacturing process while having a diaphragm for low pressure and a diaphragm for high pressure. There is something in it.
  • the pressure sensor according to one aspect of the present invention is With a conductive base and A first layer provided on the base, having a first opening and a second opening, and electrically isolated, It has a first diaphragm that is provided on the opposite side of the base in the first layer and overlaps with the first opening in a plan view, and a second diaphragm that overlaps with the second opening in a plan view, and is conductive.
  • the vertical sectional view of the pressure sensor which concerns on 1st Embodiment of this invention The vertical sectional view of the chip for a pressure sensor provided in the pressure sensor which concerns on 1st Embodiment of this invention.
  • the figure which shows the equivalent circuit of the chip for a pressure sensor of FIG. The graph which shows the capacitance value of the capacitor formed in the opening with respect to the pressure acting on a diaphragm.
  • a flowchart showing a pressure measurement process A flowchart showing a flag switching determination process.
  • the vertical sectional view of the chip for a pressure sensor provided in the pressure sensor which concerns on 2nd Embodiment of this invention The vertical sectional view of the chip for a pressure sensor provided in the pressure sensor which concerns on 3rd Embodiment of this invention.
  • the pressure sensor is With a conductive base and A first layer provided on the base, having a first opening and a second opening, and electrically isolated, It has a first diaphragm that is provided on the opposite side of the base in the first layer and overlaps with the first opening in a plan view, and a second diaphragm that overlaps with the second opening in a plan view, and is conductive.
  • the pressure sensor is provided with two closed openings (first opening and second opening) in the first layer. Further, the pressure sensor is provided with a first diaphragm facing the first opening and a second diaphragm facing the second opening on the second layer.
  • the second diaphragm In the second opening where the dielectric film is arranged, the second diaphragm is in contact with the dielectric film, and the space between the second diaphragm and the dielectric film is based on the contact area between the second diaphragm and the dielectric film. Capacitance can be determined. In this case, the second diaphragm operates in touch mode. On the other hand, in the first opening, the capacitance of the first opening is determined based on the gap between the first diaphragm and the base, etc., in a state where the first diaphragm is not in contact with other parts such as the base. be able to. In this case, the first diaphragm operates in the normal mode (non-touch mode).
  • the capacitance can be increased more than in the normal mode. Therefore, the touch mode is suitable for detecting high voltage. Therefore, according to this configuration, the operation is performed in the touch mode without making the manufacturing process complicated, such as partially changing the thickness of the second layer or providing protrusions on the second layer.
  • the second diaphragm to be operated can be a high pressure diaphragm
  • the first diaphragm operating in the normal mode can be a low pressure diaphragm.
  • a getter is arranged in the second opening.
  • the getter adsorbs the residual gas in the enclosed space.
  • the pressure of the second opening in which the getter is arranged becomes lower than the pressure of the first opening. Therefore, the pressure at which the second diaphragm contacts the dielectric film can be made lower than the pressure at which the first diaphragm contacts the base or the like.
  • the second diaphragm becomes a dielectric film before the first diaphragm comes into contact with the base or the like and cannot operate in the normal mode. It can be operated in touch mode by touching. As a result, in the process, it is possible to smoothly switch the diaphragm output by the pressure sensor from the first diaphragm for low pressure to the second diaphragm for high pressure.
  • the distance between the getter and the central portion of the second opening in the plan view may be longer than the distance between the dielectric film and the central portion of the second opening in the plan view.
  • the central portion of the second diaphragm in the plan view bends more than the outer edge portion in the plan view of the second diaphragm. According to this configuration, the distance between the getter and the center of the second opening in plan view is longer than the distance between the dielectric film and the center of the second opening in plan view. Therefore, it is possible to reduce the possibility that the bent second diaphragm comes into contact with the getter before it comes into contact with the dielectric film.
  • the getter is supported by the base, and the thickness of the getter may be thinner than the thickness of the dielectric film.
  • both the getter and the dielectric film are supported by the base, and the thickness of the getter is thinner than the thickness of the dielectric film. Therefore, it is possible to reduce the possibility that the bent second diaphragm comes into contact with the getter before it comes into contact with the dielectric film.
  • the getter is supported by the base, the dielectric film is supported by the base via the getter, and the total of the thickness of the getter and the thickness of the dielectric film is from the second layer. It may be thin.
  • the getter in addition to the position different from the dielectric film in the plan view, the getter is also arranged at the position overlapping with the dielectric film in the plan view. Therefore, the volume of the getter arranged in the second opening can be increased. As a result, the amount of gas adsorbed by the getter increases, so that the pressure at the second opening can be further reduced.
  • the getter may be provided over the entire surface of the base facing the second opening.
  • the volume of the getter arranged in the second opening can be increased as compared with the configuration in which the getter is provided only in a part of the base facing the second opening. ..
  • the amount of gas adsorbed by the getter increases, so that the pressure at the second opening can be further reduced.
  • the pressure sensor includes the base, the first diaphragm, and a control unit electrically connected to the second diaphragm.
  • the control unit The first value, which is the capacitance value or resistance value between the first diaphragm and the base, is continuously monitored, and the first pressure information regarding the pressure acting on the first diaphragm based on the first value. Is calculated, The second value, which is the capacitance value or resistance value between the second diaphragm and the base, is continuously monitored, and the second pressure information regarding the pressure acting on the second diaphragm based on the second value.
  • the first value at that time is provided on condition that the difference between the latest value of the first value and the latest value of the first value one unit time before the latest value is larger than the preset set value.
  • the pressure information is used as the first contact pressure information.
  • the second value at that time is provided on condition that the difference between the latest value of the second value and the latest value of the second value one unit time before the latest value is larger than the preset set value.
  • the pressure information may be used as the second contact pressure information.
  • control unit can determine that the first diaphragm has come into contact with the base or the like by determining the first contact pressure information. Further, the control unit can determine that the second diaphragm has come into contact with the dielectric film by determining the second contact pressure information.
  • the control unit determines that the first contact pressure information has not been determined. As a condition, the first pressure information is output, the first contact pressure information and the second contact pressure information are both determined, and the first set pressure information preset is added to the second contact pressure information. The second pressure information is output on condition that the first contact pressure information is larger than the added pressure information.
  • the control unit when the pressure acting on the pressure sensor increases from a value below the atmospheric pressure, the control unit outputs the first pressure information on condition that the first contact pressure information has not been determined. That is, in a state where the first diaphragm is not in contact with the base or the like, the control unit can output the first pressure information according to the amount of deflection of the first diaphragm as information regarding the pressure acting on the pressure sensor.
  • the control unit determines both the first contact pressure information and the second contact pressure information, and the first.
  • the second pressure information is output on condition that the contact pressure information is larger than the added pressure information.
  • the second contact pressure information is information corresponding to the lower pressure than the first contact pressure information. Therefore, when the pressure corresponding to the first contact pressure information acts on the pressure sensor and the first diaphragm comes into contact with the base or the like, the second diaphragm is already in contact with the dielectric film, and the second diaphragm is in touch mode. It is working normally. Therefore, even when the pressure information output by the control unit as the pressure acting on the pressure sensor is switched from the first pressure information to the second pressure information when the above conditions are satisfied, the control unit outputs the pressure information. The accuracy of the pressure information to be applied can be kept good.
  • the control unit is abnormal on the condition that the first contact pressure information is smaller than the additive pressure information, or the second contact pressure information is not determined when the first contact pressure information is determined. Information indicating that may be output.
  • the control unit When the first pressure information and the second pressure information calculated by the control unit are smaller than a value corresponding to the atmospheric pressure, the control unit has not determined the second contact pressure information. On condition that the second pressure information is output, both the first contact pressure information and the second contact pressure information are determined, and the second set pressure information preset from the first contact pressure information is determined.
  • the first pressure information may be output on condition that the second contact pressure information is smaller than the subtraction pressure information obtained by subtracting.
  • the control unit when the pressure acting on the pressure sensor becomes lower than the atmospheric pressure, the control unit outputs the second pressure information on condition that the second contact pressure information has not been determined. That is, in a state where the second diaphragm is in contact with the dielectric film, the control unit uses the second pressure information according to the contact area between the second diaphragm and the dielectric film as information regarding the pressure acting on the pressure sensor. Can be output.
  • the control unit determines both the first contact pressure information and the second contact pressure information, and the second contact pressure information is determined.
  • the first pressure information is output on condition that the contact pressure information is smaller than the subtraction pressure information.
  • the second contact pressure information is information corresponding to the lower pressure than the first contact pressure information. Therefore, when the pressure corresponding to the second contact pressure information acts on the pressure sensor and the second diaphragm is separated from the dielectric film, the first diaphragm is already separated from the base or the like, and the first diaphragm is in the normal mode. It is working normally. Therefore, even when the pressure information output by the control unit as the pressure acting on the pressure sensor is switched from the second pressure information to the first pressure information when the above conditions are satisfied, the control unit outputs the pressure information. The accuracy of the pressure information to be applied can be kept good.
  • the control unit is abnormal on the condition that the second contact pressure information is larger than the subtraction pressure information, or the first contact pressure information is not determined when the second contact pressure information is determined. Information indicating that may be output.
  • FIG. 1 is a vertical sectional view of a pressure sensor according to the first embodiment of the present invention.
  • the pressure sensor 1 includes a substrate 10, a pressure sensor chip 20, an integrated circuit (ASIC (Application Specific Integrated Circuit)) 30 for a specific application, a first coating portion 40, and a second coating. It is provided with a unit 50.
  • ASIC 30 Application Specific Integrated Circuit
  • the ASIC 30 is an example of a control unit.
  • the substrate 10 is a plate-shaped member.
  • the substrate 10 is made of a resin such as epoxy or phenol, ceramic, or a material such as aluminum.
  • Wiring patterns, pads, through holes, and the like made of metal such as copper are formed on the outer surface of the substrate 10. Wiring patterns, pads, and through holes can be electrically connected to each other.
  • the pressure sensor chip 20 senses a minute pressure.
  • the pressure sensor chip 20 includes two diaphragms (first diaphragm 23B and second diaphragm 23C, see FIG. 2), which will be described later.
  • the first diaphragm 23B and the second diaphragm 23C sense pressure by bending. That is, the pressure sensor 1 can measure two pressures.
  • the pressure sensor chip 20 is mounted on the upper surface 10A of the substrate 10.
  • the mounting means various known means can be adopted.
  • the pressure sensor chip 20 is mounted on the substrate 10 by attaching a base 21 (see FIG. 2), which will be described later, to the upper surface 10A with an adhesive.
  • the outer shape of the pressure sensor chip 20 is a rectangular parallelepiped shape.
  • the pressure sensor chip 20 may have a shape other than a rectangular parallelepiped, for example, a cylindrical shape.
  • the pressure sensor chip 20 is a device configured by MEMS (Micro Electro Mechanical Systems, microelectromechanical system).
  • MEMS Micro Electro Mechanical Systems, microelectromechanical system
  • the pressure sensor chip 20 has a structure in which a plurality of layers are laminated. The configuration of the pressure sensor chip 20 will be described in detail later.
  • the ASIC 30 is mounted on the upper surface 10A of the substrate 10.
  • various known means can be adopted.
  • the ASIC 30 is attached to the upper surface 10A by an adhesive.
  • the ASIC 30 is connected to the pressure sensor chip 20 via a plurality of conductive wires (for example, the wire 31 shown in FIG. 1) made of aluminum, copper, or the like.
  • the ASIC 30 is electrically connected to a plurality of pads 33 formed on the outer surface of the substrate 10 via a plurality of conductive wires 32 made of aluminum, copper, or the like. In FIG. 1, only one wire 31 and 32 are shown, and only one pad 33 is shown.
  • the pressure sensor 1 includes three wires 31. One end of each of the three wires 31 is connected to each of the pads 24A to 24C (see FIG. 3) described later. The other end of each of the three wires 31 is connected to the ASIC 30.
  • the ASIC 30 has a function of processing pressure information calculated by processing a signal input from the pressure sensor chip 20 via the wire 31 and outputting the pressure information to the outside via the wire 32. The function will be described in detail later.
  • the first covering portion 40 and the second covering portion 50 are made of a resin such as an epoxy resin.
  • the first covering portion 40 covers the upper surface 10A of the substrate 10, the pressure sensor chip 20, the ASIC 30, and the wires 31 and 32.
  • the first covering portion 40 includes an opening 41.
  • the opening 41 exposes a part of the pressure sensor chip 20 (details, the first diaphragm 23B and the second diaphragm 23C, which will be described later) to the outside.
  • the second covering portion 50 is joined to the first covering portion 40.
  • the second covering portion 50 is joined to the side of the first covering portion 40 opposite to the side in contact with the pressure sensor chip 20.
  • the second covering portion 50 includes a tubular cap 51.
  • the cap 51 projects so as to be separated from the first covering portion 40 and the pressure sensor chip 20.
  • the internal space 53 of the cap 51 communicates with the opening 41.
  • each side of the pressure sensor chip 20 which is a rectangular parallelepiped are defined as the longitudinal direction 2, the lateral direction 3, and the height direction 4, respectively.
  • FIG. 2 is a vertical cross-sectional view of a pressure sensor chip included in the pressure sensor according to the first embodiment of the present invention.
  • FIG. 3 is a plan view of a pressure sensor chip included in the pressure sensor according to the first embodiment of the present invention.
  • the lateral direction 3 is the depth direction of the paper surface of FIG.
  • the base 21 side is defined as the lower side and the conductive layer 23 side is defined as the upper side.
  • the longitudinal direction 2, the lateral direction 3, and the height direction 4 are orthogonal to each other.
  • the pressure sensor chip 20 includes a base 21, an insulating layer 22, a conductive layer 23, three pads 24A to 24C, dielectric films 26 and 28, and a getter 27. And prepare.
  • the insulating layer is an example of the first layer.
  • the conductive layer 23 is an example of the second layer.
  • the base 21 and the conductive layer 23 are conductors.
  • the base 21 and the conductive layer 23 are made of silicon.
  • the insulating layer 22 is an electrically insulated insulator.
  • the insulating layer 22 is made of silicon dioxide.
  • the lower surface 21A of the base 21 is joined to the upper surface 10A (see FIG. 1) of the substrate 10.
  • the insulating layer 22 is joined to the upper surface 21B of the base 21. That is, the insulating layer 22 is provided on the base 21.
  • the conductive layer 23 is joined to the upper surface 22A of the insulating layer 22. That is, the conductive layer 23 is provided on the opposite side of the insulating layer 22 from the base 21.
  • the above-mentioned first covering portion 40 (see FIG. 1) is bonded to the upper surface 23A of the conductive layer 23.
  • the pressure sensor chip 20 is a stack of a base 21, an insulating layer 22, and a conductive layer 23 in this order from the bottom.
  • the thickness of the base 21, the insulating layer 22, and the conductive layer 23 is not limited to the thickness shown in FIG.
  • the pressure sensor chip 20 is covered with a first covering portion 40 in a portion other than the lower surface thereof (specifically, the lower surface 21A of the base 21).
  • the base 21 supports the pad 24C.
  • the base 21 is electrically connected to the pad 24C.
  • openings 22B and 22C are formed in the insulating layer 22.
  • the opening 22B is an example of the first opening.
  • the opening 22C is an example of the second opening.
  • the opening 22B is sealed by being surrounded by the base 21, the insulating layer 22, and the first diaphragm 23B of the conductive layer 23.
  • the opening 22C is sealed by being surrounded by the base 21, the insulating layer 22, and the second diaphragm 23C of the conductive layer 23.
  • the openings 22B and 22C are rectangular in a plan view when the pressure sensor chip 20 is viewed from above, but may have a shape other than the rectangular shape (for example, a circular shape).
  • the conductive layer 23 is located at the top of the pressure sensor chip 20.
  • the conductive layer 23 includes a first diaphragm 23B, a second diaphragm 23C, an outer peripheral portion 23D, and communication portions 23E and 23F.
  • the outer peripheral portion 23D surrounds the first diaphragm 23B, the second diaphragm 23C, and the communication portions 23E and 23F in a plan view.
  • the first diaphragm 23B is electrically connected to the pad 24A via the communication portion 23E.
  • the second diaphragm 23C is electrically connected to the pad 24B via the communication portion 23F.
  • the pads 24A and 24B are supported by the upper surface 22A of the insulating layer 22.
  • the first diaphragm 23B and the communication portion 23E and the second diaphragm 23C and the communication portion 23F are formed with a gap between the outer peripheral portion 23D.
  • the first diaphragm 23B and the communication portion 23E are separated from the second diaphragm 23C and the communication portion 23F via the outer peripheral portion 23D.
  • the first diaphragm 23B faces the upper surface 21B of the base 21 via the opening 22B. That is, in a plan view, the first diaphragm 23B overlaps with the opening 22B.
  • the second diaphragm 23C faces the upper surface 21B of the base 21 via the opening 22C. That is, in a plan view, the second diaphragm 23C overlaps with the opening 22C.
  • the first diaphragm 23B and the second diaphragm 23C are exposed to the outside of the pressure sensor 1 via the opening 41 of the first covering portion 40 and the internal space 53 of the cap 51.
  • the first diaphragm 23B and the second diaphragm 23C have the same shape and the same area.
  • the first diaphragm 23B and the second diaphragm 23C do not have to have exactly the same shape, and may have substantially the same shape.
  • the first diaphragm 23B and the second diaphragm 23C do not have to have completely the same area, and may have substantially the same area.
  • the first diaphragm 23B and the second diaphragm 23C may have different shapes or different areas.
  • the dielectric film 26 and the getter 27 are arranged in the opening 22C.
  • the dielectric film 26 is supported by the upper surface 21B of the base 21.
  • the dielectric film 26 is made of a dielectric such as ceramic or plastic.
  • the length of the dielectric film 26 in the height direction 4 is shorter than the length of the insulating layer 22 in the height direction 4.
  • the thickness T1 of the dielectric film 26 is thinner than the thickness T2 of the insulating layer 22. Therefore, there is a gap between the upper surface 26A of the dielectric film 26 and the lower surface 23Ca of the second diaphragm 23C.
  • the getter 27 is supported by the upper surface 21B of the base 21.
  • the getter 27 is an adsorbent that absorbs gas (for example, oxygen, nitrogen, carbon dioxide, etc.) in the opening 22C.
  • gas for example, oxygen, nitrogen, carbon dioxide, etc.
  • the getter 27 is made of titanium.
  • the getter 27 may be made of, for example, thorium, vanadium, magnesium, or the like, in addition to titanium.
  • the getter 27 is arranged so as to surround the dielectric film 26 in a plan view.
  • the getter 27 is arranged between the dielectric film 26 and the side surface 22D of the insulating layer 22 in a plan view.
  • the distance D1 between the getter 27 and the central portion 22Ca of the opening 22C in the plan view is longer than the distance D1 between the dielectric film 26 and the central portion 22Ca of the opening 22C in the plan view.
  • the dielectric film 26 includes the central portion 22Ca of the opening 22C. Therefore, the distance between the dielectric film 26 and the central portion 22Ca of the opening 22C in a plan view is zero.
  • the dielectric film 26 may be arranged at a position away from the central portion 22Ca of the opening 22C, as shown by the broken line in FIG. In such a case, in the first embodiment, the distance D2 between the dielectric film 26 and the central portion 22Ca of the opening 22C in a plan view is shorter than the distance D1.
  • the length of the getter 27 in the height direction 4 is shorter than the length of the dielectric film 26 in the height direction 4. In other words, the thickness T3 of the getter 27 is thinner than the thickness T1 of the dielectric film 26.
  • the dielectric film 28 is arranged in the opening 22B.
  • the dielectric film 28 is supported by the upper surface 21B of the base 21.
  • the dielectric film 28 is made of a dielectric such as ceramic or plastic.
  • the length of the dielectric film 28 in the height direction 4 is shorter than the length of the dielectric film 26 in the height direction 4.
  • the dielectric film 28 may not be arranged in the opening 22B. That is, the pressure sensor chip 20 does not have to include the dielectric film 28.
  • FIG. 4 is a diagram showing an equivalent circuit of the pressure sensor chip of FIG. 2.
  • FIG. 5 is a graph showing the capacitance value of the capacitor formed in the opening with respect to the pressure acting on the diaphragm.
  • the horizontal axis shows the pressure (unit: kPa) acting on the first diaphragm 23B and the second diaphragm 23C
  • the vertical axis shows the capacitance value (unit: aF) of each of the capacitors C1 and C2.
  • the characteristics of the capacitor C1 are shown by the solid line
  • the characteristics of the capacitor C2 are shown by the alternate long and short dash line.
  • the fluid By connecting the cap 51 shown in FIG. 1 to a pipe or the like, the fluid can be taken into the cap 51.
  • the pressure due to the fluid is applied from the internal space 53 of the cap 51 (see FIG. 1) to the first diaphragm 23B and the second diaphragm 23C through the opening 41 (see FIGS. 1 and 2) of the first covering portion 40. It works.
  • the first diaphragm 23B and the second diaphragm 23C bend downward.
  • the greater the pressure acting on the first diaphragm 23B and the second diaphragm 23C the greater the amount of deflection of the first diaphragm 23B and the second diaphragm 23C.
  • the first diaphragm 23B and the second diaphragm 23C When the amount of deflection of the first diaphragm 23B and the second diaphragm 23C is small (when the pressure range PR1 in FIG. 5), the first diaphragm 23B is separated from the dielectric film 28, and the second diaphragm 23C is separated from the dielectric film 26. is seperated.
  • the capacitance value of the capacitor C1 is shown in FIG. It becomes larger than the state shown in. Further, in this case, since the distance between the second diaphragm 23C and the base 21 is smaller than when the second diaphragm 23C is not bent (the state shown in FIG. 1), the capacitance value of the capacitor C2 is set. It is larger than that in the state shown in FIG.
  • C is the capacitance value of the capacitor
  • d is the distance between the electrodes constituting the capacitor
  • S is the area of the electrodes constituting the capacitor
  • ⁇ is the dielectric constant of the substance existing between the opposing electrodes.
  • the substances existing between the two electrodes (the first diaphragm 23B and the base 21) constituting the capacitor C1 are a gas such as air existing in the opening 22B and the dielectric film 28.
  • the substances existing between the two electrodes (second diaphragm 23C and base 21) constituting the capacitor C2 are a gas such as air existing in the opening 22C and the dielectric film 26.
  • the dielectric film 26 is longer in the height direction 4 than the dielectric film 26. Therefore, the capacitance value of the capacitor C2 is larger than the capacitance value of the capacitor C1.
  • the second diaphragm 23C comes into contact with the upper surface 26A of the dielectric film 26. ..
  • the capacitance value of the capacitor C2 increases sharply. That is, at this time, the relationship between the capacitance value of the capacitor C2 and the pressure acting on the second diaphragm 23C becomes non-linear.
  • the pressure acting on the first diaphragm 23B and the second diaphragm 23C is the second contact pressure PC2.
  • the distance (length in the height direction 4) between the upper surface 28A of the dielectric film 28 and the first diaphragm 23B in the opening 22B is the distance between the upper surface 26A and the second diaphragm 23C of the dielectric film 26 in the opening 22C. It is longer than the interval (length in the height direction 4). Therefore, when the second diaphragm 23C is in contact with the upper surface 26A of the dielectric film 26, the first diaphragm 23B is not in contact with the upper surface 28A of the dielectric film 28. Therefore, the relationship between the capacitance value of the capacitor C1 and the pressure acting on the first diaphragm 23B still follows the above-mentioned equation.
  • the first diaphragm 23B comes into contact with the upper surface 28A of the dielectric film 28.
  • the capacitance value of the capacitor C1 increases sharply. That is, at this time, the relationship between the capacitance value of the capacitor C1 and the pressure acting on the first diaphragm 23B becomes non-linear.
  • the pressure acting on the first diaphragm 23B and the second diaphragm 23C is the first contact pressure PC1.
  • the relationship between the capacitance value of the capacitor C2 and the pressure acting on the second diaphragm 23C maintains a linear shape.
  • the pressure sensor chip 20 does not have the dielectric film 28, that is, when the dielectric film 28 is not arranged in the opening 22B, when the amount of deflection of the first diaphragm 23B becomes large as described above, the first diaphragm 23B is used. 1 The diaphragm 23B comes into contact with the upper surface 21B of the base 21. At this time, the capacitance value of the capacitor C1 decreases sharply.
  • the contact area of the first diaphragm 23B with respect to the upper surface 28A of the dielectric film 28 becomes large.
  • the capacitance value of the capacitor C1 increases.
  • the relationship between the capacitance value of the capacitor C1 and the pressure acting on the first diaphragm 23B is generally linear.
  • the capacitance value of the capacitor C2 also maintains a substantially linearity with respect to the pressure acting on the second diaphragm 23C. growing.
  • the ASIC 30 is connected to the pads 24A to 24C of the pressure sensor chip 20 via three wires 31. That is, the ASIC 30 is electrically connected to the base 21, the first diaphragm 23B, and the second diaphragm 23C.
  • the ASIC 30 has a pressure measurement function of processing pressure information calculated by processing a signal input from the pressure sensor chip 20 via the wire 31 and outputting the pressure information to the outside via the wire 32.
  • FIG. 6 is a flowchart showing the pressure measurement process. Hereinafter, the pressure measurement process will be described with reference to FIG.
  • the ASIC 30 continuously monitors the capacitance value C1 n of the capacitor C1 and the capacitance value C2 n of the capacitor C2 by repeatedly executing step S50 described later from the start to the end of the pressure measurement process.
  • the ASIC 30 sets the capacitance value C1 n of the capacitor C1 and the capacitance value C2 n of the capacitor C2 to the current values from the base 21, the first diaphragm 23B, and the second diaphragm 23C, and the base 21, the first diaphragm 23B, and so on. And, it is calculated based on the voltage value applied to the second diaphragm 23C.
  • Continuous monitoring includes not only continuous monitoring but also short-time monitoring.
  • the ASIC 30 monitors the capacitance values C1 n and C2 n of the capacitors C1 and C2 every unit time.
  • the unit time is set short enough to discriminate whether or not the relationship between the capacitance values C1 n and C2 n of the capacitors C1 and C2 and the pressure acting on the first diaphragm 23B and the second diaphragm 23C is non-linear.
  • the unit time is set, for example, between 5 (ms) and 100 (ms).
  • n is a natural number.
  • the capacitance value of the capacitor C1 monitored i-th from the start of the pressure measurement process is indicated as C1 i
  • the capacitance value of the capacitor C2 monitored i + 1th is indicated as C2 i + 1 .
  • the capacitance value C1 n of the capacitor C1 is an example of the first value.
  • the capacitance value C2 n of the capacitor C2 is an example of the second value.
  • the ASIC 30 starts the above monitoring (S10).
  • the ASIC 30 has a capacitance value C1 n of the capacitor C1 monitored in the initial period from the start of the pressure measurement (for example, one capacitance value C1 1 or a plurality of capacitance values C1 1 to C1 5 etc.), and a capacitance value of the capacitor C2. Based on at least one of C2 n , it is determined whether or not the pressure acting on the first diaphragm 23B and the second diaphragm 23C is higher than the atmospheric pressure (S20).
  • the ASIC30 sets the flag to ON (S30).
  • the ASIC30 sets the flag to OFF (S40). In the first embodiment, when the pressure is equal to the atmospheric pressure, the ASIC 30 sets the flag to OFF.
  • the flag is stored in a memory provided inside or outside the ASIC 30 (hereinafter, simply referred to as a memory). As will be described later, when the flag is OFF, the ASIC 30 outputs the first pressure information P1 n based on the capacitance value C1 n of the capacitor C1 to the outside, and when the flag is ON, the ASIC 30 is the capacitance value C2 of the capacitor C2. The second pressure information P2 n based on n is output to the outside.
  • the ASIC 30 monitors the capacitance value C1 i of the capacitor C1 and the capacitance value C2 i of the capacitor C2 (S50).
  • i is the number of times of monitoring. For example, in the case of the capacitance value C1 i monitored 99th from the start of measurement, i is 99.
  • the ASIC 30 calculates the first pressure information P1 i based on the capacity value C1 i monitored in step S50, and calculates the second pressure information P2 i based on the capacity value C2 i monitored in step S50 (. S60). That is, a plurality of first pressure information P1 n is calculated corresponding to the plurality of capacitance values C1 n , and a plurality of second pressure information P2 n is calculated corresponding to the plurality of capacitance values C2 n .
  • the plurality of first pressure information P1 n including the first pressure information P1 i is information regarding the pressure acting on the first diaphragm 23B.
  • the plurality of second pressure information P2 n including the second pressure information P2 i is information regarding the pressure acting on the second diaphragm 23C.
  • each of the first pressure information P1 n and the second pressure information P2 n is numerical information indicating the magnitude of the pressure.
  • each of the first pressure information P1 n and the second pressure information P2 n may have the same values as the corresponding capacitance values C1 n and C2 n .
  • the flag switching determination process is a process of determining whether or not to switch the flag from OFF to ON or from ON to OFF.
  • the flag switching determination process will be described in detail later.
  • the ASIC 30 refers to the flag stored in the memory (S80).
  • the flag is ON (S80: yes)
  • the ASIC 30 outputs the second pressure information P2 i to the outside (S90).
  • the flag is OFF (S80: no)
  • the ASIC 30 outputs the first pressure information P1 i to the outside (S100).
  • the outside is, for example, a display unit of an electronic device to which the pressure sensor 1 is connected. The pressure value corresponding to the first pressure information P1 i or the second pressure information P2 i is displayed on this display unit.
  • the calculation of the first pressure information P1 n and the second pressure information P2 n is sequentially executed each time the capacitance values C1 n and C2 n are monitored. However, the calculation may be performed collectively every time a predetermined number of capacity values C1 n and C2 n are monitored.
  • steps S50 to S100 are executed again.
  • the pressure measurement is terminated, for example, when the power supply to the ASIC 30 from the outside is stopped (S110: yes).
  • FIG. 7 is a flowchart showing the flag switching determination process.
  • the flag switching determination process in FIG. 6 will be described with reference to FIG. 7.
  • the ASIC 30 refers to the flag stored in the memory (S210).
  • the flag is OFF (S210: no)
  • the ASIC 30 executes the processes after step S220 shown below.
  • the flag is ON (S210: yes)
  • the ASIC 30 executes the processes after step S300, which will be described later.
  • the ASIC 30 When the flag is OFF (S210: no), the ASIC 30 has a unit time before the capacity value C2 i of the capacity values C2 n of the capacitor C2 from the capacity value C2 i which is the latest value of the capacity value C2 n of the capacitor C2. It is determined whether or not the value obtained by subtracting the latest capacitance value C2 i-1 of is larger than the set value CS (S220).
  • the set value CS is a preset value and is stored in the memory.
  • the set value CS is the capacitor C2 when the relationship between the capacitance value C2 n of the capacitor C2 and the pressure acting on the first diaphragm 23B and the second diaphragm 23C is not non-linear (when according to the above equation or when it is linear). It is set to a value larger than the difference between the latest value of the capacitance value C2 n and the latest value of the capacitance value C2 n of the capacitor C2, and smaller than the difference between the latest value and the latest value when the relationship is non-linear. ..
  • the set value CS is set based on the thickness of the second diaphragm 23C (the length in the height direction 4), the distance between the second diaphragm 23C and the dielectric film 26, and the like.
  • the ASIC 30 sets the second pressure information P2 i based on the capacity value C2 i to the second contact pressure information PCI2. Is stored in the memory (S230).
  • the second contact pressure information PCI2 is information corresponding to the pressure when the second diaphragm 23C comes into contact with the upper surface 26A of the dielectric film 26 (second contact pressure PC2 (see FIG. 5)).
  • the ASIC 30 executes step S240 described below without executing step S230.
  • the ASIC 30 executes step S240 without executing step S230.
  • the ASIC 30 has a capacitance value C1 i , which is the latest value of the capacitance value C1 n of the capacitor C1, and the latest capacitance value C1 i- It is determined whether or not the value obtained by subtracting 1 is larger than the set value CS (S240).
  • the set value CS is a preset value and is stored in the memory.
  • the set value CS is set based on the thickness of the first diaphragm 23B (length in the height direction 4), the distance between the first diaphragm 23B and the dielectric film 28, and the like.
  • the set value CS in step S240 is the same value as the set value CS in step S220, but may be a value different from the set value CS in step S220.
  • the ASIC 30 finishes the flag switching determination process and executes the processing after step S80 of the measurement process. (See FIG. 6).
  • the ASIC 30 sets the first pressure information P1 i based on the capacity value C1 i to the first contact pressure information PCI1. It is stored in the memory as (S250).
  • the first contact pressure information PCI1 is information corresponding to the pressure when the first diaphragm 23B comes into contact with the upper surface 21B of the base 21 (first contact pressure PC1 (see FIG. 5)).
  • the ASIC 30 executes step S250 even when the value obtained by subtracting the capacity value C1 i -1 from the capacity value C1 i is equal to the set value CS.
  • the ASIC 30 determines whether or not the second contact pressure information PCI2 has already been determined (S260).
  • the ASIC 30 determines the first contact pressure information PCI1. Is larger than the added pressure information (S270).
  • the added pressure information is information obtained by adding the first set pressure information PS1 to the second contact pressure information PCI2. That is, the additional pressure information is PCI2 + PS1.
  • the first set pressure information PS1 is added to the first diaphragm 23B from the time when the second diaphragm 23C comes into contact with the upper surface 26A of the dielectric film 26 until the first diaphragm 23B comes into contact with the upper surface 28A of the dielectric film 28.
  • This is information set based on the required pressure, that is, the pressure difference between the first contact pressure PC1 and the second contact pressure PC2.
  • the first set pressure information PS1 is the difference between the distance between the first diaphragm 23B and the upper surface 28A of the dielectric film 28 and the distance between the second diaphragm 23C and the upper surface 26A of the dielectric film 26, and the first diaphragm 23B. It is set based on the thickness and the like.
  • the first set pressure information PS1 is set to a value corresponding to a pressure difference slightly smaller than the pressure difference between the first contact pressure PC1 and the second contact pressure PC2.
  • the ASIC30 sets the flag to ON (S280). In the first embodiment, the ASIC 30 sets the flag to ON even when the first contact pressure information PCI1 has the same value as the added pressure information (PCI2 + PS1) (S280).
  • step S260 When the second contact pressure information PCI2 is not determined in step S260 (S260: no), the first contact pressure information PCI1 is determined in the immediately preceding step S250, while the second contact pressure information PCI2 is determined. Not. In this case, the ASIC 30 outputs information indicating an abnormality to the outside (S290), and the pressure measurement is completed.
  • step S270 when the first contact pressure information PCI1 is smaller than the added pressure information (PCI2 + PS1) (S270: no), the ASIC 30 outputs information indicating an abnormality to the outside (S290), and the pressure measurement is completed. To.
  • step S210 the ASIC 30 sets the capacitance value C1 i , which is the latest value of the capacitance value C1 n of the capacitor C1, from the capacitance value C1 i among the capacitance values C1 n of the capacitor C1. It is determined whether or not the value subtracted from the latest capacitance value C1 i-1 before the unit time is larger than the set value CS (S300).
  • the set value CS is a preset value and is stored in the memory.
  • the set value CS is set in the same manner as the set value CS in step S240.
  • the set value CS in step S300 is the same as the set value CS in steps S220 and S240, but may be different from the set value CS in steps S220 and S240.
  • the ASIC 30 When the value obtained by subtracting the capacity value C1 i from the difference from the capacity value C1 i-1 is larger than the set value CS (S300: yes), the ASIC 30 first contacts the first pressure information P1 i based on the capacity value C1 i . It is stored in the memory as the pressure information PCI1 (S310).
  • the ASIC 30 executes step S320 described below without executing step S310.
  • the ASIC 30 executes step S320 without executing step S310.
  • the ASIC 30 sets the capacitance value C2 i , which is the latest value of the capacitance value C2 n of the capacitor C2, to the latest capacitance value C2 i- unit time before the capacitance value C2 i of the capacitance values C2 n of the capacitor C2 . It is determined whether or not the value subtracted from 1 is larger than the set value CS (S320).
  • the set value CS is a preset value and is stored in the memory.
  • the set value CS is set in the same manner as the set value CS in step S220.
  • the set value CS in step S320 has the same value as the set value CS in steps S220, S240, and S300, but even if the value is different from the set value CS in steps S220, S240, and S300. good.
  • the ASIC 30 finishes the flag switching determination process and executes the process after step S80 of the measurement process. (See FIG. 6).
  • the ASIC 30 uses the second pressure information P2 i based on the capacity value C2 i as the second contact pressure information PCI2. It is stored in the memory as (S330). In the first embodiment, the ASIC 30 executes step S330 even when the value obtained by subtracting the capacity value C2 i from the capacity value C2 i-1 is equal to the set value CS.
  • the ASIC 30 determines whether or not the first contact pressure information PCI1 has already been determined (S340).
  • the ASIC 30 determines the second contact pressure information PCI2. Is smaller than the subtraction pressure information (S350).
  • the subtracted pressure information is information obtained by subtracting the second set pressure information PS2 from the first contact pressure information PCI1. That is, the subtraction pressure information is PCI1-PS2.
  • the second set pressure information PS2 is reduced with respect to the second diaphragm 23C from the time the first diaphragm 23B is separated from the upper surface 28A of the dielectric film 28 until the second diaphragm 23C is separated from the upper surface 26A of the dielectric film 26.
  • This is information set based on the required pressure, that is, the pressure difference between the first contact pressure PC1 and the second contact pressure PC2.
  • the second set pressure information PS2 is the difference between the distance between the first diaphragm 23B and the upper surface 28A of the dielectric film 28 and the distance between the second diaphragm 23C and the upper surface 26A of the dielectric film 26, and the second diaphragm 23C. It is set based on the thickness and the like. In the first embodiment, the second set pressure information PS2 is set to the same value as the first set pressure information PS1.
  • the ASIC30 sets the flag to OFF (S360). In the first embodiment, the ASIC 30 sets the flag to OFF even when the second contact pressure information PCI2 has the same value as the subtraction pressure information (PCI1-PS2) (S360).
  • step S340 When the first contact pressure information PCI1 is not determined in step S340 (S340: no), the second contact pressure information PCI2 is determined in the immediately preceding step S330, while the first contact pressure information PCI1 is determined. Not. In this case, the ASIC 30 outputs information indicating an abnormality to the outside (S290), and the pressure measurement is completed.
  • step S350 when the second contact pressure information PCI2 is larger than the subtraction pressure information (PCI1-PS2) (S350: no), the ASIC30 outputs information indicating an abnormality to the outside (S290), and the pressure is measured. It will be terminated.
  • PCI1-PS2 subtraction pressure information
  • the ASIC 30 acts on the first diaphragm 23B and the second diaphragm 23C based on at least one of the capacitance value C1 n of the capacitor C1 and the capacitance value C2 n of the capacitor C2 monitored (S10). It is determined that the pressure is equal to or lower than the atmospheric pressure (S20: no). The ASIC 30 sets the flag to OFF (S40).
  • the ASIC 30 monitors the capacitance value C1 i of the capacitor C1 and the capacitance value C2 i of the capacitor C2 (S50), and outputs the first pressure information P1 i (S100) because the flag is OFF (S80: no). And repeat.
  • the first contact pressure information PCI1 has not been determined. That is, the ASIC 30 outputs the first pressure information P1 n on condition that the first contact pressure information PCI1 has not been determined.
  • the ASIC 30 stores the second pressure information P2 i based on the capacitance value C2 i in the memory as the second contact pressure information PCI 2 (S230).
  • the ASIC 30 stores the first pressure information P1 i based on the capacitance value C1 i in the memory as the first contact pressure information PCI 1 (S250).
  • the ASIC 30 determines whether the first contact pressure information PCI1 is larger than the additional pressure information (PCI2 + PS1). (S270). In this example, the first contact pressure information PCI1 is larger than the additive pressure information (PCI2 + PS1) (S270: yes). Therefore, the ASIC 30 switches the flag from OFF to ON (S280). The processing in the case of an abnormality is as described above.
  • the ASIC 30 monitors the capacitance value C1 i of the capacitor C1 and the capacitance value C2 i of the capacitor C2 (S50), and outputs the second pressure information P2 i (S90) because the flag is ON (S80: yes). And repeat.
  • the ASIC 30 acts on the first diaphragm 23B and the second diaphragm 23C based on at least one of the capacitance value C1 n of the capacitor C1 and the capacitance value C2 n of the capacitor C2 monitored (S10). It is determined that the pressure is higher than the atmospheric pressure (S20: yes). The ASIC 30 sets the flag to ON (S30).
  • the ASIC 30 repeats the monitoring of the capacitance value C1 i of the capacitor C1 and the capacitance value C2 i of the capacitor C2 (S50), and the output of the second pressure information P2 i due to the flag being ON (S80: yes). ..
  • the second contact pressure information PCI2 has not been determined. That is, the ASIC 30 outputs the second pressure information P2 n on condition that the second contact pressure information PCI 2 has not been determined.
  • the capacitance value C1 i is changed to the capacitance value C1 i-1 in the flag switching determination process (S70).
  • the value subtracted from is larger than the set value CS (S300: yes).
  • the ASIC 30 stores the first pressure information P1 i based on the capacitance value C1 i in the memory as the first contact pressure information PCI 1 (S310).
  • the ASIC 30 stores the second pressure information P2 i based on the capacitance value C2 i in the memory as the second contact pressure information PCI 2 (S330).
  • the ASIC30 determines whether the second contact pressure information PCI2 is smaller than the subtraction pressure information (PCI1-PS2). Judgment (S350). In this example, the second contact pressure information PCI2 is smaller than the subtraction pressure information (PCI1-PS2) (S350: yes). Therefore, the ASIC 30 switches the flag from ON to OFF (S360). The processing in the case of an abnormality is as described above.
  • the ASIC 30 monitors the capacitance value C1 i of the capacitor C1 and the capacitance value C2 i of the capacitor C2 (S50), and outputs the first pressure information P1 i (S100) because the flag is OFF (S80: no). And repeat.
  • the pressure sensor 1 includes two sealed openings 22B and 22C in the insulating layer 22. Further, the pressure sensor 1 includes a first diaphragm 23B facing the opening 22B and a second diaphragm 23C facing the opening 22C in the conductive layer 23.
  • the second diaphragm 23C and the dielectric are in contact with the second diaphragm 23C based on the contact area between the second diaphragm 23C and the dielectric film 26 in a state where the second diaphragm 23C is in contact with the dielectric film 26.
  • the capacitance between the body membrane 26 and the body membrane 26 can be determined.
  • the second diaphragm 23C operates in the touch mode.
  • the capacitance of the opening 22B is determined based on the gap between the first diaphragm 23B and the dielectric film 28 in a state where the first diaphragm 23B is not in contact with the dielectric film 28. Can be done. In this case, the first diaphragm 23B operates in the normal mode (non-touch mode).
  • the capacitance can be increased more than in the normal mode. Therefore, the touch mode is suitable for detecting high voltage. Therefore, according to the first embodiment, the touch mode is not configured to complicate the manufacturing process, such as partially changing the thickness of the conductive layer 23 or providing protrusions on the conductive layer 23.
  • the second diaphragm 23C operating in the above can be used as a diaphragm for high pressure
  • the first diaphragm 23B operating in normal mode can be used as a diaphragm for low pressure.
  • the getter 27 is arranged in the opening 22C.
  • the getter 27 adsorbs the residual gas in the closed space.
  • the pressure of the opening 22C in which the getter 27 is arranged becomes lower than the pressure of the opening 22B. Therefore, the pressure at which the second diaphragm 23C contacts the dielectric film 26 (second contact pressure PC2) can be made lower than the pressure at which the first diaphragm 23B contacts the dielectric film 28 (first contact pressure PC1). ..
  • the second diaphragm 23C is dielectric before the first diaphragm 23B comes into contact with the dielectric film 28 and cannot operate in the normal mode. It comes into contact with the body membrane 26 and can operate in the touch mode.
  • the central portion of the second diaphragm 23C in a plan view bends more than the outer edge portion of the second diaphragm 23C in a plan view.
  • the distance between the getter 27 and the central portion of the opening 22C in the plan view is longer than the distance between the dielectric film 26 and the central portion of the opening 22C in the plan view. Therefore, it is possible to reduce the possibility that the bent second diaphragm 23C comes into contact with the getter 27 before it comes into contact with the dielectric film 26.
  • both the getter 27 and the dielectric film 26 are supported by the base 21, and the thickness of the getter 27 is thinner than the thickness of the dielectric film 26. Therefore, it is possible to reduce the possibility that the bent second diaphragm 23C comes into contact with the getter 27 before it comes into contact with the dielectric film 26.
  • the ASIC 30 can determine that the first diaphragm 23B has come into contact with the dielectric film 28 by determining the first contact pressure information PCI1. Further, the ASIC 30 can determine that the second diaphragm 23C has come into contact with the dielectric film 26 by determining the second contact pressure information PCI2.
  • the ASIC 30 uses the first pressure information P1 on the condition that the first contact pressure information PCI1 has not been determined. Output n . That is, in a state where the first diaphragm 23B is not in contact with the dielectric film 28, the ASIC 30 uses the first pressure information P1 n according to the amount of deflection of the first diaphragm 23B as information regarding the pressure acting on the pressure sensor 1. Can be output.
  • the ASIC 30 determines both the first contact pressure information PCI1 and the second contact pressure information PCI2, and The second pressure information P2 n is output on condition that the first contact pressure information PCI1 is larger than the added pressure information (PCI2 + PS1).
  • the second contact pressure information PCI2 is information corresponding to a lower pressure than the first contact pressure information PCI1.
  • the second diaphragm 23C is already in contact with the dielectric film 26.
  • the second diaphragm 23C is operating normally in the touch mode. That is, when the first diaphragm 23B comes into contact with the dielectric film 28, the relationship between the capacitance value of the capacitor C2 and the pressure acting on the second diaphragm 23C is generally linear. Therefore, even when the pressure information output by the ASIC 30 as the pressure acting on the pressure sensor 1 when the above conditions are satisfied is switched from the first pressure information P1 n to the second pressure information P2 n . The accuracy of the pressure information output by the ASIC 30 can be kept good.
  • the ASIC 30 uses the second pressure information P2 on condition that the second contact pressure information PCI2 has not been determined. Output n . That is, in a state where the second diaphragm 23C is in contact with the dielectric film 26, the ASIC 30 provides the pressure sensor 1 with the second pressure information P2 n according to the contact area between the second diaphragm 23C and the dielectric film 26. It can be output as information about the acting pressure.
  • the ASIC 30 determines both the first contact pressure information PCI1 and the second contact pressure information PCI2, and The first pressure information P1 n is output on condition that the second contact pressure information PCI2 is smaller than the subtraction pressure information (PCI1-PS2).
  • the second contact pressure information PCI2 is information corresponding to a lower pressure than the first contact pressure information PCI1.
  • the first embodiment it is possible to notify the outside that the pressure sensor 1 is not functioning normally.
  • the getter 27 is supported by the base 21, but may be supported by other than the base 21.
  • the getter 27 may be supported by the side surface 22D of the insulating layer 22 or the lower surface 23Ca of the second diaphragm 23C.
  • the thicknesses (lengths in the height direction 4) of the base 21, the insulating layer 22, the conductive layer 23, the dielectric film 26, the dielectric film 28, and the getter 27 included in the pressure sensor chip 20 are shown in FIG. Not limited to the thickness shown.
  • the insulating layer 22 is thicker than the conductive layer 23, but the insulating layer 22 and the conductive layer 23 may have the same thickness.
  • the ASIC 30 calculated the first pressure information P1 i based on the capacitance value C1 i , and calculated the second pressure information P2 i based on the capacitance value C2 i .
  • the first pressure information P1 i and the second pressure information P2 i may be calculated by other than the capacitance values C1 i and C2 i .
  • the ASIC 30 is based on the current values from the base 21, the first diaphragm 23B, and the second diaphragm 23C, and the voltage values applied to the base 21, the first diaphragm 23B, and the second diaphragm 23C.
  • the resistance value between the pads 24A and 24C in the pressure sensor chip 20 and the resistance value between the pads 24B and 24C in the pressure sensor chip 20 may be calculated.
  • the ASIC 30 calculates the first pressure information P1 i based on the resistance value between the pads 24A and 24C in the pressure sensor chip 20, and the first is based on the resistance value between the pads 24B and 24C in the pressure sensor chip 20. 2 Pressure information P2 i may be calculated.
  • the presence or absence of a sharp increase in the capacitor C1 was determined in step S240, and the presence or absence of a sharp decrease in the capacitor C1 was determined in step S300. It was
  • step S240 it may be determined in step S240 whether or not the capacitor C1 is suddenly decreased, and whether or not the capacitor C1 is rapidly increased in step S300.
  • the ASIC 30 configured by the circuit corresponded to the control unit. That is, the above-mentioned operation was realized by a circuit, that is, by hardware.
  • the control unit is not limited to hardware such as a circuit.
  • the control unit may be composed of an arithmetic unit and a memory. In this case, the arithmetic unit executes the program stored in the memory, that is, the software realizes the above-mentioned operation. Further, the above-mentioned operation may be realized by a combination of hardware and software.
  • FIG. 8 is a vertical cross-sectional view of a pressure sensor chip included in the pressure sensor according to the second embodiment of the present invention.
  • the difference between the pressure sensor chip 20A of the pressure sensor 1 according to the second embodiment and the pressure sensor chip 20 of the pressure sensor 1 according to the first embodiment is that the getter 37 has an opening in the upper surface 21B of the base 21. It is provided over the entire surface of the portion facing 22C, and the dielectric film 36 is supported by the getter 37.
  • the getter 37 is supported by the base 21.
  • the getter 37 is provided over the entire surface of the upper surface 21B of the base 21 facing the opening 22C.
  • the getter 37 has the same configuration as the getter 27 of the first embodiment.
  • the getter 37 may be provided only on a part of the upper surface 21B of the base 21 facing the opening 22C.
  • the dielectric film 36 is supported by the upper surface 37A of the getter 37. That is, the dielectric film 36 is supported by the base 21 via the getter 37.
  • the thickness of the dielectric film 36 (the length in the height direction 4) is thinner than that of the dielectric film 26 of the first embodiment by the thickness of the getter 37. In other respects, the dielectric film 36 has the same configuration as the dielectric film 26 of the first embodiment.
  • the thickness of the dielectric film 36 is arbitrary as long as the total of the thickness of the getter 37 and the thickness of the dielectric film 36 is thinner than the insulating layer 22. That is, it is sufficient that a gap is formed between the upper surface 36A of the dielectric film 36 and the lower surface 23Ca of the second diaphragm 23C.
  • the getter 37 in addition to the position different from the dielectric film 36 in the plan view, the getter 37 is also arranged at the position overlapping with the dielectric film 36 in the plan view. Therefore, the volume of the getter 37 arranged in the opening 22C can be increased. As a result, the amount of gas adsorbed by the getter 37 increases, so that the pressure at the opening 22C can be further reduced.
  • the volume of the getter 37 arranged in the opening 22C is larger than that in the configuration in which the getter 37 is provided only in a part of the base 21 facing the opening 22C. be able to. As a result, the amount of gas adsorbed by the getter 37 increases, so that the pressure at the opening 22C can be further reduced.
  • FIG. 9 is a vertical cross-sectional view of a pressure sensor chip included in the pressure sensor according to the third embodiment of the present invention.
  • the difference between the pressure sensor chip 20B of the pressure sensor 1 according to the third embodiment and the pressure sensor chip 20 of the pressure sensor 1 according to the first embodiment is that the getter 47 is joined to the lower surface 23Ca of the second diaphragm 23C. That is the point.
  • the getter 47 has the same configuration as the getter 27 of the first embodiment except that it is joined to the lower surface 23Ca of the second diaphragm 23C.
  • the getter 47 is provided over the entire surface of the lower surface 23Ca of the second diaphragm 23C facing the opening 22C, but the portion of the lower surface 23Ca facing the opening 22C. It may be provided only in a part.
  • Pressure sensor 20 Pressure sensor chip 21 Base 22 Insulation layer (1st layer) 22B opening (first opening) 22C opening (second opening) 23 Conductive layer (second layer) 23B 1st diaphragm 23C 2nd diaphragm 26 Dielectric film 27 Getter 30 ASIC (Control unit) C1 n capacity value (first value) C2 n capacity value (second value) D1 distance D2 distance P1 n 1st pressure information P2 n 2nd pressure information PCI1 1st contact pressure information PCI2 2nd contact pressure information PS1 1st set pressure information PS2 2nd set pressure information

Abstract

Provided is a pressure sensor that makes it possible to avoid complication of a manufacturing process although having a low-pressure diaphragm and a high-pressure diaphragm. A pressure sensor chip 20 included in this pressure sensor is provided with: a base 21 that has conductivity; an insulation layer 22 that is provided on the base 21, that has opening parts 22B, 22C, and that is electrically insulated; a conductive layer 23 that is provided on an upper surface 22A of the insulation layer 22, that has a first diaphragm 23B overlapping the opening part 22B in a plan view and a second diaphragm 23C overlapping the opening part 22C in a plan view, and that has conductivity; a dielectric film 26 that is provided in the opening part 22C, that is supported by the base 21, and that is thinner than the insulation layer 22; and a getter 27 that is provided in the opening part 22C. The opening parts 22B, 22C are sealed.

Description

圧力センサPressure sensor
　本発明は、外部からの圧力を測定するための圧力センサに関する。 The present invention relates to a pressure sensor for measuring pressure from the outside.
　ダイアフラムの変位量に基づいてダイアフラムに作用する圧力を測定する圧力センサが知られている。圧力センサには、低圧用のダイアフラムと、高圧用のダイアフラムとを備えたものがある（例えば、特許文献１参照）。 A pressure sensor that measures the pressure acting on the diaphragm based on the displacement of the diaphragm is known. Some pressure sensors include a diaphragm for low pressure and a diaphragm for high pressure (see, for example, Patent Document 1).
　特許文献１に開示された圧力センサでは、高圧用のダイアフラムが低圧用のダイアフラムより厚い。また、特許文献１に開示された圧力センサでは、低圧用のダイアフラムに、突起が設けられている。これにより、圧力センサに高圧が印加されたときに、突起が基板に接触する。その結果、高圧用ダイアフラムより薄い低圧用のダイアフラムが過大に変位して破損することが防止される。 In the pressure sensor disclosed in Patent Document 1, the diaphragm for high pressure is thicker than the diaphragm for low pressure. Further, in the pressure sensor disclosed in Patent Document 1, a protrusion is provided on the diaphragm for low pressure. As a result, when a high pressure is applied to the pressure sensor, the protrusions come into contact with the substrate. As a result, the low pressure diaphragm thinner than the high pressure diaphragm is prevented from being excessively displaced and damaged.
特開平１１－６４１３７号公報Japanese Unexamined Patent Publication No. 11-6437
　特許文献１に開示された圧力センサでは、高圧用のダイアフラムと低圧用のダイアフラムとは、同一のシリコン板上に形成されている。そのため、圧力センサの製造工程において、高圧用のダイアフラムを低圧用のダイアフラムより厚く構成するために、同一のシリコン板上に厚さの異なる部分を設けるという複雑な工程が必要である。 In the pressure sensor disclosed in Patent Document 1, the diaphragm for high pressure and the diaphragm for low pressure are formed on the same silicon plate. Therefore, in the manufacturing process of the pressure sensor, in order to make the diaphragm for high pressure thicker than the diaphragm for low pressure, a complicated process of providing portions having different thicknesses on the same silicon plate is required.
　また、特許文献１に開示された圧力センサでは、低圧用のダイアフラムに、突起が設けられている。そのため、圧力センサの製造工程において、シリコン板に突起を設けるという追加の工程が必要である。 Further, in the pressure sensor disclosed in Patent Document 1, a protrusion is provided on the diaphragm for low pressure. Therefore, in the manufacturing process of the pressure sensor, an additional process of providing a protrusion on the silicon plate is required.
　つまり、特許文献１に開示された圧力センサでは、製造工程が煩雑化してしまう。 That is, the pressure sensor disclosed in Patent Document 1 complicates the manufacturing process.
　従って、本発明の目的は、前記課題を解決することにあって、低圧用のダイアフラムと高圧用のダイアフラムとを有しつつも、製造工程の煩雑化を回避することができる圧力センサを提供することにある。 Therefore, an object of the present invention is to solve the above-mentioned problems, and to provide a pressure sensor capable of avoiding complicated manufacturing process while having a diaphragm for low pressure and a diaphragm for high pressure. There is something in it.
　前記目的を達成するために、本発明は以下のように構成する。
　本発明の一態様に係る圧力センサは、
　導電性を有する基台と、
　前記基台上に設けられ、第１開口部及び第２開口部を有し、電気的に絶縁された第１層と、
　前記第１層における前記基台と反対側に設けられ、平面視において前記第１開口部と重複する第１ダイアフラム、及び平面視において前記第２開口部と重複する第２ダイアフラムを有し、導電性を有する第２層と、
　前記第２開口部に配置され、前記基台に支持され、前記第１層より薄い誘電体膜と、
　前記第２開口部に配置されたゲッターと、を備え、
　前記第１開口部及び前記第２開口部は、密閉されている。 In order to achieve the above object, the present invention is configured as follows.
The pressure sensor according to one aspect of the present invention is
With a conductive base and
A first layer provided on the base, having a first opening and a second opening, and electrically isolated,
It has a first diaphragm that is provided on the opposite side of the base in the first layer and overlaps with the first opening in a plan view, and a second diaphragm that overlaps with the second opening in a plan view, and is conductive. The second layer with sex and
A dielectric film arranged in the second opening, supported by the base, and thinner than the first layer,
With a getter arranged in the second opening,
The first opening and the second opening are hermetically sealed.
　本発明によれば、低圧用のダイアフラムと高圧用のダイアフラムとを有しつつも、製造工程の煩雑化を回避することができる。 According to the present invention, it is possible to avoid complication of the manufacturing process while having a diaphragm for low pressure and a diaphragm for high pressure.
本発明の第１実施形態に係る圧力センサの縦断面図。The vertical sectional view of the pressure sensor which concerns on 1st Embodiment of this invention. 本発明の第１実施形態に係る圧力センサが備える圧力センサ用チップの縦断面図。The vertical sectional view of the chip for a pressure sensor provided in the pressure sensor which concerns on 1st Embodiment of this invention. 本発明の第１実施形態に係る圧力センサが備える圧力センサ用チップの平面図。The plan view of the chip for a pressure sensor provided in the pressure sensor which concerns on 1st Embodiment of this invention. 図２の圧力センサ用チップの等価回路を示す図。The figure which shows the equivalent circuit of the chip for a pressure sensor of FIG. ダイアフラムに作用する圧力に対する開口部に形成されたコンデンサの容量値を示すグラフ。The graph which shows the capacitance value of the capacitor formed in the opening with respect to the pressure acting on a diaphragm. 圧力測定処理を示すフローチャート。A flowchart showing a pressure measurement process. フラグ切替判定処理を示すフローチャート。A flowchart showing a flag switching determination process. 本発明の第２実施形態に係る圧力センサが備える圧力センサ用チップの縦断面図。The vertical sectional view of the chip for a pressure sensor provided in the pressure sensor which concerns on 2nd Embodiment of this invention. 本発明の第３実施形態に係る圧力センサが備える圧力センサ用チップの縦断面図。The vertical sectional view of the chip for a pressure sensor provided in the pressure sensor which concerns on 3rd Embodiment of this invention.
　本発明の一態様に係る圧力センサは、
　導電性を有する基台と、
　前記基台上に設けられ、第１開口部及び第２開口部を有し、電気的に絶縁された第１層と、
　前記第１層における前記基台と反対側に設けられ、平面視において前記第１開口部と重複する第１ダイアフラム、及び平面視において前記第２開口部と重複する第２ダイアフラムを有し、導電性を有する第２層と、
　前記第２開口部に配置され、前記基台に支持され、前記第１層より薄い誘電体膜と、
　前記第２開口部に配置されたゲッターと、を備え、
　前記第１開口部及び前記第２開口部は、密閉されている。 The pressure sensor according to one aspect of the present invention is
With a conductive base and
A first layer provided on the base, having a first opening and a second opening, and electrically isolated,
It has a first diaphragm that is provided on the opposite side of the base in the first layer and overlaps with the first opening in a plan view, and a second diaphragm that overlaps with the second opening in a plan view, and is conductive. The second layer with sex and
A dielectric film arranged in the second opening, supported by the base, and thinner than the first layer,
With a getter arranged in the second opening,
The first opening and the second opening are hermetically sealed.
　この構成によれば、圧力センサは、第１層に、２つの密閉された開口部（第１開口部及び第２開口部）を備えている。また、圧力センサは、第２層に、第１開口部に面した第１ダイアフラムと、第２開口部に面した第２ダイアフラムとを備えている。 According to this configuration, the pressure sensor is provided with two closed openings (first opening and second opening) in the first layer. Further, the pressure sensor is provided with a first diaphragm facing the first opening and a second diaphragm facing the second opening on the second layer.
　誘電体膜が配置された第２開口部では、第２ダイアフラムが誘電体膜と接触した状態で、第２ダイアフラムと誘電体膜との接触面積に基づいて第２ダイアフラムと誘電体膜との間の静電容量を決定することができる。この場合、第２ダイアフラムはタッチモードで動作する。一方、第１開口部では、第１ダイアフラムが基台等の他部分と接触していない状態で、第１ダイアフラムと基台等とのギャップに基づいて第１開口部の静電容量を決定することができる。この場合、第１ダイアフラムはノーマルモード（非タッチモード）で動作する。 In the second opening where the dielectric film is arranged, the second diaphragm is in contact with the dielectric film, and the space between the second diaphragm and the dielectric film is based on the contact area between the second diaphragm and the dielectric film. Capacitance can be determined. In this case, the second diaphragm operates in touch mode. On the other hand, in the first opening, the capacitance of the first opening is determined based on the gap between the first diaphragm and the base, etc., in a state where the first diaphragm is not in contact with other parts such as the base. be able to. In this case, the first diaphragm operates in the normal mode (non-touch mode).
　ここで、タッチモードでは、ノーマルモードより静電容量を多くできる。そのため、タッチモードは、高圧の検出に適している。よって、この構成によれば、第２層の厚みを部分的に変えたり、第２層に突起を設けたりする等の、製造工程が煩雑化するような構成とすることなく、タッチモードで動作する第２ダイアフラムを高圧用のダイアフラムとし、ノーマルモードで動作する第１ダイアフラムを低圧用のダイアフラムとすることができる。 Here, in the touch mode, the capacitance can be increased more than in the normal mode. Therefore, the touch mode is suitable for detecting high voltage. Therefore, according to this configuration, the operation is performed in the touch mode without making the manufacturing process complicated, such as partially changing the thickness of the second layer or providing protrusions on the second layer. The second diaphragm to be operated can be a high pressure diaphragm, and the first diaphragm operating in the normal mode can be a low pressure diaphragm.
　また、この構成によれば、第２開口部にゲッターが配置されている。ゲッターは、密閉空間内の残留気体を吸着する。これにより、ゲッターが配置された第２開口部の圧力は、第１開口部の圧力より低圧となる。そのため、第２ダイアフラムが誘電体膜に接触する圧力を、第１ダイアフラムが基台等に接触する圧力より低くすることができる。これにより、例えば、第２層に作用する圧力が低圧から高圧へ変化する過程において、第１ダイアフラムが基台等に接触してノーマルモードで動作できなくなる前に、第２ダイアフラムが誘電体膜に接触してタッチモードで動作可能となる。その結果、当該過程において、圧力センサが出力するダイアフラムを、低圧用の第１ダイアフラムから高圧用の第２ダイアフラムへ切り替えることを円滑に実行することができる。 Further, according to this configuration, a getter is arranged in the second opening. The getter adsorbs the residual gas in the enclosed space. As a result, the pressure of the second opening in which the getter is arranged becomes lower than the pressure of the first opening. Therefore, the pressure at which the second diaphragm contacts the dielectric film can be made lower than the pressure at which the first diaphragm contacts the base or the like. As a result, for example, in the process of changing the pressure acting on the second layer from low pressure to high pressure, the second diaphragm becomes a dielectric film before the first diaphragm comes into contact with the base or the like and cannot operate in the normal mode. It can be operated in touch mode by touching. As a result, in the process, it is possible to smoothly switch the diaphragm output by the pressure sensor from the first diaphragm for low pressure to the second diaphragm for high pressure.
　平面視における前記ゲッターと前記第２開口部の中心部との距離は、平面視における前記誘電体膜と前記第２開口部の中心部との距離より長くてもよい。 The distance between the getter and the central portion of the second opening in the plan view may be longer than the distance between the dielectric film and the central portion of the second opening in the plan view.
　第２ダイアフラムが撓む際、第２ダイアフラムの平面視における中央部は、第２ダイアフラムの平面視における外縁部より大きく撓む。この構成によれば、平面視におけるゲッターと第２開口部の中心部との距離は、平面視における誘電体膜と第２開口部の中心部との距離より長い。そのため、撓んだ第２ダイアフラムが誘電体膜に接触するより前にゲッターに接触する可能性を低くすることができる。 When the second diaphragm bends, the central portion of the second diaphragm in the plan view bends more than the outer edge portion in the plan view of the second diaphragm. According to this configuration, the distance between the getter and the center of the second opening in plan view is longer than the distance between the dielectric film and the center of the second opening in plan view. Therefore, it is possible to reduce the possibility that the bent second diaphragm comes into contact with the getter before it comes into contact with the dielectric film.
　前記ゲッターは、前記基台に支持され、前記ゲッターの厚みは、前記誘電体膜の厚みより薄くてもよい。 The getter is supported by the base, and the thickness of the getter may be thinner than the thickness of the dielectric film.
　この構成によれば、ゲッター及び誘電体膜はいずれも基台に支持されており、且つゲッターの厚みは誘電体膜の厚みより薄い。そのため、撓んだ第２ダイアフラムが誘電体膜に接触するより前にゲッターに接触する可能性を低くすることができる。 According to this configuration, both the getter and the dielectric film are supported by the base, and the thickness of the getter is thinner than the thickness of the dielectric film. Therefore, it is possible to reduce the possibility that the bent second diaphragm comes into contact with the getter before it comes into contact with the dielectric film.
　前記ゲッターは、前記基台に支持され、前記誘電体膜は、前記ゲッターを介して前記基台に支持され、前記ゲッターの厚みと前記誘電体膜の厚みとの合計は、前記第２層より薄くてもよい。 The getter is supported by the base, the dielectric film is supported by the base via the getter, and the total of the thickness of the getter and the thickness of the dielectric film is from the second layer. It may be thin.
　この構成によれば、平面視における誘電体膜と異なる位置に加えて、平面視における誘電体膜と重複する位置にもゲッターが配置されている。そのため、第２開口部に配置されるゲッターの体積を大きくすることができる。その結果、ゲッターが吸着する気体量が多くなるため、第２開口部の圧力をより低くすることができる。 According to this configuration, in addition to the position different from the dielectric film in the plan view, the getter is also arranged at the position overlapping with the dielectric film in the plan view. Therefore, the volume of the getter arranged in the second opening can be increased. As a result, the amount of gas adsorbed by the getter increases, so that the pressure at the second opening can be further reduced.
　前記ゲッターは、前記基台のうちの前記第２開口部に面した部分の全面に亘って設けられていてもよい。 The getter may be provided over the entire surface of the base facing the second opening.
　この構成によれば、ゲッターが基台のうちの第２開口部に面した部分の一部のみに設けられている構成より、第２開口部に配置されるゲッターの体積を大きくすることができる。その結果、ゲッターが吸着する気体量が多くなるため、第２開口部の圧力をより低くすることができる。 According to this configuration, the volume of the getter arranged in the second opening can be increased as compared with the configuration in which the getter is provided only in a part of the base facing the second opening. .. As a result, the amount of gas adsorbed by the getter increases, so that the pressure at the second opening can be further reduced.
　本発明の一態様に係る圧力センサは、前記基台、前記第１ダイアフラム、及び前記第２ダイアフラムと電気的に接続された制御部を備え、
　前記制御部は、
　前記第１ダイアフラムと前記基台との間の容量値または抵抗値である第１値を連続的にモニタリングして、前記第１値に基づいて前記第１ダイアフラムに作用する圧力に関する第１圧力情報を算出し、
　前記第２ダイアフラムと前記基台との間の容量値または抵抗値である第２値を連続的にモニタリングして、前記第２値に基づいて前記第２ダイアフラムに作用する圧力に関する第２圧力情報を算出し、
　前記第１値の最新値と前記第１値のうちの当該最新値より単位時間前の直近値との差が予め設定された設定値より大きくなったことを条件として、そのときの前記第１圧力情報を第１接触圧力情報とし、
　前記第２値の最新値と前記第２値のうちの当該最新値より単位時間前の直近値との差が予め設定された設定値より大きくなったことを条件として、そのときの前記第２圧力情報を第２接触圧力情報としてもよい。 The pressure sensor according to one aspect of the present invention includes the base, the first diaphragm, and a control unit electrically connected to the second diaphragm.
The control unit
The first value, which is the capacitance value or resistance value between the first diaphragm and the base, is continuously monitored, and the first pressure information regarding the pressure acting on the first diaphragm based on the first value. Is calculated,
The second value, which is the capacitance value or resistance value between the second diaphragm and the base, is continuously monitored, and the second pressure information regarding the pressure acting on the second diaphragm based on the second value. Is calculated,
The first value at that time is provided on condition that the difference between the latest value of the first value and the latest value of the first value one unit time before the latest value is larger than the preset set value. The pressure information is used as the first contact pressure information.
The second value at that time is provided on condition that the difference between the latest value of the second value and the latest value of the second value one unit time before the latest value is larger than the preset set value. The pressure information may be used as the second contact pressure information.
　この構成によれば、制御部は、第１接触圧力情報を決定することによって、第１ダイアフラムが基台等に接触したことを判定できる。また、制御部は、第２接触圧力情報を決定することによって、第２ダイアフラムが誘電体膜に接触したことを判定できる。 According to this configuration, the control unit can determine that the first diaphragm has come into contact with the base or the like by determining the first contact pressure information. Further, the control unit can determine that the second diaphragm has come into contact with the dielectric film by determining the second contact pressure information.
　前記制御部によって算出される前記第１圧力情報及び前記第２圧力情報が大気圧に対応する値以下から大きくなる場合において、前記制御部は、前記第１接触圧力情報が決定されていないことを条件として、前記第１圧力情報を出力し、前記第１接触圧力情報及び前記第２接触圧力情報がいずれも決定され、且つ前記第２接触圧力情報に予め設定された第１設定圧力情報を加算した加算圧力情報より前記第１接触圧力情報が大きいことを条件として、前記第２圧力情報を出力する。 When the first pressure information and the second pressure information calculated by the control unit increase from a value corresponding to the atmospheric pressure or less, the control unit determines that the first contact pressure information has not been determined. As a condition, the first pressure information is output, the first contact pressure information and the second contact pressure information are both determined, and the first set pressure information preset is added to the second contact pressure information. The second pressure information is output on condition that the first contact pressure information is larger than the added pressure information.
　この構成によれば、圧力センサに作用する圧力が大気圧以下の値から高くなる場合に、制御部は、第１接触圧力情報が決定されていないことを条件として第１圧力情報を出力する。つまり、第１ダイアフラムが基台等と接触していない状態において、制御部は、第１ダイアフラムの撓み量に応じた第１圧力情報を、圧力センサに作用する圧力に関する情報として出力できる。 According to this configuration, when the pressure acting on the pressure sensor increases from a value below the atmospheric pressure, the control unit outputs the first pressure information on condition that the first contact pressure information has not been determined. That is, in a state where the first diaphragm is not in contact with the base or the like, the control unit can output the first pressure information according to the amount of deflection of the first diaphragm as information regarding the pressure acting on the pressure sensor.
　また、この構成によれば、圧力センサに作用する圧力が大気圧以下の値から高くなる場合に、制御部は、第１接触圧力情報及び第２接触圧力情報がいずれも決定され、且つ第１接触圧力情報が加算圧力情報より大きいことを条件として第２圧力情報を出力する。ここで、ゲッターが配置された第２開口部の圧力は第１開口部の圧力より低圧であるため、第２接触圧力情報は第１接触圧力情報より低圧に対応した情報となる。そのため、第１接触圧力情報に対応する圧力が圧力センサに作用して第１ダイアフラムが基台等に接触したとき、第２ダイアフラムは既に誘電体膜に接触しており、第２ダイアフラムはタッチモードで正常に動作している。そのため、上記の条件を満たしたときに、圧力センサに作用する圧力として制御部が出力する圧力情報が、第１圧力情報から第２圧力情報に切り替えられた場合であっても、制御部が出力する圧力情報の精度を良好に保つことができる。 Further, according to this configuration, when the pressure acting on the pressure sensor becomes higher than the value below the atmospheric pressure, the control unit determines both the first contact pressure information and the second contact pressure information, and the first. The second pressure information is output on condition that the contact pressure information is larger than the added pressure information. Here, since the pressure of the second opening in which the getter is arranged is lower than the pressure of the first opening, the second contact pressure information is information corresponding to the lower pressure than the first contact pressure information. Therefore, when the pressure corresponding to the first contact pressure information acts on the pressure sensor and the first diaphragm comes into contact with the base or the like, the second diaphragm is already in contact with the dielectric film, and the second diaphragm is in touch mode. It is working normally. Therefore, even when the pressure information output by the control unit as the pressure acting on the pressure sensor is switched from the first pressure information to the second pressure information when the above conditions are satisfied, the control unit outputs the pressure information. The accuracy of the pressure information to be applied can be kept good.
　前記制御部は、前記第１接触圧力情報が前記加算圧力情報より小さいこと、または前記第１接触圧力情報が決定されたときに前記第２接触圧力情報が決定されていないことを条件として、異常を示す情報を出力してもよい。 The control unit is abnormal on the condition that the first contact pressure information is smaller than the additive pressure information, or the second contact pressure information is not determined when the first contact pressure information is determined. Information indicating that may be output.
　この構成によれば、圧力センサが正常に機能していないことを外部へ知らせることができる。 According to this configuration, it is possible to notify the outside that the pressure sensor is not functioning normally.
　前記制御部によって算出される前記第１圧力情報及び前記第２圧力情報が大気圧に対応する値より大きい値から小さくなる場合において、前記制御部は、前記第２接触圧力情報が決定されていないことを条件として、前記第２圧力情報を出力し、前記第１接触圧力情報及び前記第２接触圧力情報がいずれも決定され、且つ前記第１接触圧力情報から予め設定された第２設定圧力情報を減算した減算圧力情報より前記第２接触圧力情報が小さいことを条件として、前記第１圧力情報を出力してもよい。 When the first pressure information and the second pressure information calculated by the control unit are smaller than a value corresponding to the atmospheric pressure, the control unit has not determined the second contact pressure information. On condition that the second pressure information is output, both the first contact pressure information and the second contact pressure information are determined, and the second set pressure information preset from the first contact pressure information is determined. The first pressure information may be output on condition that the second contact pressure information is smaller than the subtraction pressure information obtained by subtracting.
　この構成によれば、圧力センサに作用する圧力が大気圧より高い値から低くなる場合に、制御部は、第２接触圧力情報が決定されていないことを条件として第２圧力情報を出力する。つまり、第２ダイアフラムが誘電体膜と接触している状態において、制御部は、第２ダイアフラムと誘電体膜との接触面積に応じた第２圧力情報を、圧力センサに作用する圧力に関する情報として出力できる。 According to this configuration, when the pressure acting on the pressure sensor becomes lower than the atmospheric pressure, the control unit outputs the second pressure information on condition that the second contact pressure information has not been determined. That is, in a state where the second diaphragm is in contact with the dielectric film, the control unit uses the second pressure information according to the contact area between the second diaphragm and the dielectric film as information regarding the pressure acting on the pressure sensor. Can be output.
　また、この構成によれば、圧力センサに作用する圧力が大気圧より高い値から低くなる場合に、制御部は、第１接触圧力情報及び第２接触圧力情報がいずれも決定され、且つ第２接触圧力情報が減算圧力情報より小さいことを条件として第１圧力情報を出力する。ここで、ゲッターが配置された第２開口部の圧力は第１開口部の圧力より低圧であるため、第２接触圧力情報は第１接触圧力情報より低圧に対応した情報となる。そのため、第２接触圧力情報に対応する圧力が圧力センサに作用して第２ダイアフラムが誘電体膜から離れたとき、第１ダイアフラムは既に基台等から離れており、第１ダイアフラムはノーマルモードで正常に動作している。そのため、上記の条件を満たしたときに、圧力センサに作用する圧力として制御部が出力する圧力情報が、第２圧力情報から第１圧力情報に切り替えられた場合であっても、制御部が出力する圧力情報の精度を良好に保つことができる。 Further, according to this configuration, when the pressure acting on the pressure sensor becomes lower than the atmospheric pressure, the control unit determines both the first contact pressure information and the second contact pressure information, and the second contact pressure information is determined. The first pressure information is output on condition that the contact pressure information is smaller than the subtraction pressure information. Here, since the pressure of the second opening in which the getter is arranged is lower than the pressure of the first opening, the second contact pressure information is information corresponding to the lower pressure than the first contact pressure information. Therefore, when the pressure corresponding to the second contact pressure information acts on the pressure sensor and the second diaphragm is separated from the dielectric film, the first diaphragm is already separated from the base or the like, and the first diaphragm is in the normal mode. It is working normally. Therefore, even when the pressure information output by the control unit as the pressure acting on the pressure sensor is switched from the second pressure information to the first pressure information when the above conditions are satisfied, the control unit outputs the pressure information. The accuracy of the pressure information to be applied can be kept good.
　前記制御部は、前記第２接触圧力情報が前記減算圧力情報より大きいこと、または前記第２接触圧力情報が決定されたときに前記第１接触圧力情報が決定されていないことを条件として、異常を示す情報を出力してもよい。 The control unit is abnormal on the condition that the second contact pressure information is larger than the subtraction pressure information, or the first contact pressure information is not determined when the second contact pressure information is determined. Information indicating that may be output.
　この構成によれば、圧力センサが正常に機能していないことを外部へ知らせることができる。 According to this configuration, it is possible to notify the outside that the pressure sensor is not functioning normally.
　＜第１実施形態＞
　図１は、本発明の第１実施形態に係る圧力センサの縦断面図である。 <First Embodiment>
FIG. 1 is a vertical sectional view of a pressure sensor according to the first embodiment of the present invention.
　図１に示すように、圧力センサ１は、基板１０と、圧力センサ用チップ２０と、特定用途向け集積回路（ＡＳＩＣ（Ａｐｐｌｉｃａｔｉｏｎ　Ｓｐｅｃｉｆｉｃ　Ｉｎｔｅｇｒａｔｅｄ　Ｃｉｒｃｕｉｔ））３０と、第１被覆部４０と、第２被覆部５０とを備えている。以下、特定用途向け集積回路３０は、ＡＳＩＣ３０と記される。ＡＳＩＣ３０は、制御部の一例である。 As shown in FIG. 1, the pressure sensor 1 includes a substrate 10, a pressure sensor chip 20, an integrated circuit (ASIC (Application Specific Integrated Circuit)) 30 for a specific application, a first coating portion 40, and a second coating. It is provided with a unit 50. Hereinafter, the integrated circuit 30 for a specific application is referred to as ASIC 30. The ASIC 30 is an example of a control unit.
　基板１０は、板状の部材である。基板１０は、エポキシやフェノールなどの樹脂、セラミック、またはアルミニウムなどの材料で構成されている。基板１０の外面には、銅などの金属で形成された配線パターン、パッド、スルーホールなどが形成されている。配線パターン、パッド、スルーホールは、互いに電気的に接続され得る。 The substrate 10 is a plate-shaped member. The substrate 10 is made of a resin such as epoxy or phenol, ceramic, or a material such as aluminum. Wiring patterns, pads, through holes, and the like made of metal such as copper are formed on the outer surface of the substrate 10. Wiring patterns, pads, and through holes can be electrically connected to each other.
　圧力センサ用チップ２０は、微小な圧力を感知するものである。圧力センサ用チップ２０は、後述する２つのダイアフラム（第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃ、図２参照）を備えている。第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃは、撓むことによって圧力を感知する。つまり、圧力センサ１は、２つの圧力を測定可能である。 The pressure sensor chip 20 senses a minute pressure. The pressure sensor chip 20 includes two diaphragms (first diaphragm 23B and second diaphragm 23C, see FIG. 2), which will be described later. The first diaphragm 23B and the second diaphragm 23C sense pressure by bending. That is, the pressure sensor 1 can measure two pressures.
　圧力センサ用チップ２０は、基板１０の上面１０Ａに実装されている。実装手段は、公知の種々の手段が採用可能である。第１実施形態において、圧力センサ用チップ２０は、後述する基台２１（図２参照）が粘着剤によって上面１０Ａに貼り付けられることによって、基板１０に実装されている。 The pressure sensor chip 20 is mounted on the upper surface 10A of the substrate 10. As the mounting means, various known means can be adopted. In the first embodiment, the pressure sensor chip 20 is mounted on the substrate 10 by attaching a base 21 (see FIG. 2), which will be described later, to the upper surface 10A with an adhesive.
　第１実施形態において、圧力センサ用チップ２０の外形は、直方体形状である。なお、圧力センサ用チップ２０は、直方体以外の形状、例えば円柱形状などであってもよい。圧力センサ用チップ２０は、ＭＥＭＳ（Ｍｉｃｒｏ　Ｅｌｅｃｔｒｏ　Ｍｅｃｈａｎｉｃａｌ　Ｓｙｓｔｅｍｓ、微小電気機械システム）で構成されたデバイスである。圧力センサ用チップ２０は、複数の層が積層された構造である。圧力センサ用チップ２０の構成は、後に詳細に説明される。 In the first embodiment, the outer shape of the pressure sensor chip 20 is a rectangular parallelepiped shape. The pressure sensor chip 20 may have a shape other than a rectangular parallelepiped, for example, a cylindrical shape. The pressure sensor chip 20 is a device configured by MEMS (Micro Electro Mechanical Systems, microelectromechanical system). The pressure sensor chip 20 has a structure in which a plurality of layers are laminated. The configuration of the pressure sensor chip 20 will be described in detail later.
　ＡＳＩＣ３０は、基板１０の上面１０Ａに実装されている。実装手段は、公知の種々の手段が採用可能である。第１実施形態において、ＡＳＩＣ３０は、粘着剤によって上面１０Ａに貼り付けられている。 The ASIC 30 is mounted on the upper surface 10A of the substrate 10. As the mounting means, various known means can be adopted. In the first embodiment, the ASIC 30 is attached to the upper surface 10A by an adhesive.
　ＡＳＩＣ３０は、アルミニウムや銅などで構成された複数の導電性のワイヤ（例えば図１に示されるワイヤ３１）を介して圧力センサ用チップ２０と接続されている。ＡＳＩＣ３０は、アルミニウムや銅などで構成された複数の導電性のワイヤ３２などを介して、基板１０の外面に形成された複数のパッド３３に電気的に接続されている。なお、図１には、ワイヤ３１，３２は各１本のみ記されており、パッド３３は１つのみ記されている。 The ASIC 30 is connected to the pressure sensor chip 20 via a plurality of conductive wires (for example, the wire 31 shown in FIG. 1) made of aluminum, copper, or the like. The ASIC 30 is electrically connected to a plurality of pads 33 formed on the outer surface of the substrate 10 via a plurality of conductive wires 32 made of aluminum, copper, or the like. In FIG. 1, only one wire 31 and 32 are shown, and only one pad 33 is shown.
　第１実施形態では、圧力センサ１は、３本のワイヤ３１を備えている。３本のワイヤ３１の各々の一端部は、後述するパッド２４Ａ～２４Ｃ（図３参照）の各々と接続されている。３本のワイヤ３１の各々の他端部は、ＡＳＩＣ３０と接続されている。 In the first embodiment, the pressure sensor 1 includes three wires 31. One end of each of the three wires 31 is connected to each of the pads 24A to 24C (see FIG. 3) described later. The other end of each of the three wires 31 is connected to the ASIC 30.
　ＡＳＩＣ３０は、圧力センサ用チップ２０からワイヤ３１を介して入力された信号を処理して算出した圧力情報を、ワイヤ３２を介して外部へ出力する機能を有する。当該機能は、後に詳細に説明される。 The ASIC 30 has a function of processing pressure information calculated by processing a signal input from the pressure sensor chip 20 via the wire 31 and outputting the pressure information to the outside via the wire 32. The function will be described in detail later.
　第１被覆部４０及び第２被覆部５０は、エポキシ樹脂などの樹脂で構成されている。 The first covering portion 40 and the second covering portion 50 are made of a resin such as an epoxy resin.
　第１被覆部４０は、基板１０の上面１０Ａ、圧力センサ用チップ２０、ＡＳＩＣ３０、及びワイヤ３１，３２を覆っている。第１被覆部４０は、開口部４１を備えている。開口部４１は、圧力センサ用チップ２０の一部（詳細には後述する第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃ）を外部に露出させる。 The first covering portion 40 covers the upper surface 10A of the substrate 10, the pressure sensor chip 20, the ASIC 30, and the wires 31 and 32. The first covering portion 40 includes an opening 41. The opening 41 exposes a part of the pressure sensor chip 20 (details, the first diaphragm 23B and the second diaphragm 23C, which will be described later) to the outside.
　第２被覆部５０は、第１被覆部４０に接合されている。第２被覆部５０は、第１被覆部４０における圧力センサ用チップ２０と接触している側とは反対側に接合されている。第２被覆部５０は、筒状のキャップ５１を備えている。キャップ５１は、第１被覆部４０及び圧力センサ用チップ２０から離れるように突出している。キャップ５１の内部空間５３は、開口部４１と連通している。 The second covering portion 50 is joined to the first covering portion 40. The second covering portion 50 is joined to the side of the first covering portion 40 opposite to the side in contact with the pressure sensor chip 20. The second covering portion 50 includes a tubular cap 51. The cap 51 projects so as to be separated from the first covering portion 40 and the pressure sensor chip 20. The internal space 53 of the cap 51 communicates with the opening 41.
　以下、圧力センサ用チップ２０の構成が、詳細に説明される。なお、以下の説明において、直方体である圧力センサ用チップ２０の各辺の方向が、それぞれ長手方向２、短手方向３、及び高さ方向４と定義される。 Hereinafter, the configuration of the pressure sensor chip 20 will be described in detail. In the following description, the directions of each side of the pressure sensor chip 20 which is a rectangular parallelepiped are defined as the longitudinal direction 2, the lateral direction 3, and the height direction 4, respectively.
　図２は、本発明の第１実施形態に係る圧力センサが備える圧力センサ用チップの縦断面図である。図３は、本発明の第１実施形態に係る圧力センサが備える圧力センサ用チップの平面図である。図２において、短手方向３は、図２の紙面の奥行方向である。図２に示すように、高さ方向４において、基台２１側が下、導電層２３側が上と定義される。長手方向２、短手方向３、及び高さ方向４は、互いに直交している。 FIG. 2 is a vertical cross-sectional view of a pressure sensor chip included in the pressure sensor according to the first embodiment of the present invention. FIG. 3 is a plan view of a pressure sensor chip included in the pressure sensor according to the first embodiment of the present invention. In FIG. 2, the lateral direction 3 is the depth direction of the paper surface of FIG. As shown in FIG. 2, in the height direction 4, the base 21 side is defined as the lower side and the conductive layer 23 side is defined as the upper side. The longitudinal direction 2, the lateral direction 3, and the height direction 4 are orthogonal to each other.
　図２及び図３に示すように、圧力センサ用チップ２０は、基台２１と、絶縁層２２と、導電層２３と、３つのパッド２４Ａ～２４Ｃと、誘電体膜２６，２８と、ゲッター２７とを備える。絶縁層は、第１層の一例である。導電層２３は、第２層の一例である。 As shown in FIGS. 2 and 3, the pressure sensor chip 20 includes a base 21, an insulating layer 22, a conductive layer 23, three pads 24A to 24C, dielectric films 26 and 28, and a getter 27. And prepare. The insulating layer is an example of the first layer. The conductive layer 23 is an example of the second layer.
　基台２１及び導電層２３は、導電体である。第１実施形態において、基台２１及び導電層２３は、シリコンで構成されている。絶縁層２２、電気的に絶縁された絶縁体である。第１実施形態において、絶縁層２２は、二酸化シリコンで構成されている。 The base 21 and the conductive layer 23 are conductors. In the first embodiment, the base 21 and the conductive layer 23 are made of silicon. The insulating layer 22 is an electrically insulated insulator. In the first embodiment, the insulating layer 22 is made of silicon dioxide.
　図２に示すように、基台２１の下面２１Ａは、基板１０の上面１０Ａ（図１参照）に接合されている。絶縁層２２は、基台２１の上面２１Ｂに接合されている。つまり、絶縁層２２は、基台２１上に設けられている。導電層２３は、絶縁層２２の上面２２Ａに接合されている。つまり、導電層２３は、絶縁層２２における基台２１と反対側に設けられている。導電層２３の上面２３Ａに、上述した第１被覆部４０（図１参照）が接合されている。 As shown in FIG. 2, the lower surface 21A of the base 21 is joined to the upper surface 10A (see FIG. 1) of the substrate 10. The insulating layer 22 is joined to the upper surface 21B of the base 21. That is, the insulating layer 22 is provided on the base 21. The conductive layer 23 is joined to the upper surface 22A of the insulating layer 22. That is, the conductive layer 23 is provided on the opposite side of the insulating layer 22 from the base 21. The above-mentioned first covering portion 40 (see FIG. 1) is bonded to the upper surface 23A of the conductive layer 23.
　以上より、圧力センサ用チップ２０は、下から順に、基台２１、絶縁層２２、及び導電層２３が積層されたものである。 From the above, the pressure sensor chip 20 is a stack of a base 21, an insulating layer 22, and a conductive layer 23 in this order from the bottom.
　なお、基台２１、絶縁層２２、及び導電層２３の厚みは、図２に示された厚みに限らない。 The thickness of the base 21, the insulating layer 22, and the conductive layer 23 is not limited to the thickness shown in FIG.
　図１に示すように、圧力センサ用チップ２０は、その下面（詳細には基台２１の下面２１Ａ）を除く部分において、第１被覆部４０によって覆われている。 As shown in FIG. 1, the pressure sensor chip 20 is covered with a first covering portion 40 in a portion other than the lower surface thereof (specifically, the lower surface 21A of the base 21).
　図３に示すように、基台２１は、パッド２４Ｃを支持している。基台２１は、パッド２４Ｃと電気的に接続されている。 As shown in FIG. 3, the base 21 supports the pad 24C. The base 21 is electrically connected to the pad 24C.
　図２及び図３に示すように、絶縁層２２には、開口部２２Ｂ，２２Ｃが形成されている。開口部２２Ｂは第１開口部の一例である。開口部２２Ｃは第２開口部の一例である。開口部２２Ｂは、基台２１、絶縁層２２、及び導電層２３の第１ダイアフラム２３Ｂによって囲まれることによって、密閉されている。開口部２２Ｃは、基台２１、絶縁層２２、及び導電層２３の第２ダイアフラム２３Ｃによって囲まれることによって、密閉されている。第１実施形態において、開口部２２Ｂ，２２Ｃは、それぞれ圧力センサ用チップ２０を上方から視た平面視において矩形であるが、矩形以外の形（例えば円形）であってもよい。 As shown in FIGS. 2 and 3, openings 22B and 22C are formed in the insulating layer 22. The opening 22B is an example of the first opening. The opening 22C is an example of the second opening. The opening 22B is sealed by being surrounded by the base 21, the insulating layer 22, and the first diaphragm 23B of the conductive layer 23. The opening 22C is sealed by being surrounded by the base 21, the insulating layer 22, and the second diaphragm 23C of the conductive layer 23. In the first embodiment, the openings 22B and 22C are rectangular in a plan view when the pressure sensor chip 20 is viewed from above, but may have a shape other than the rectangular shape (for example, a circular shape).
　図２に示すように、導電層２３は、圧力センサ用チップ２０の最も上に位置する。 As shown in FIG. 2, the conductive layer 23 is located at the top of the pressure sensor chip 20.
　図３に示すように、導電層２３は、第１ダイアフラム２３Ｂと、第２ダイアフラム２３Ｃと、外周部２３Ｄと、連通部２３Ｅ，２３Ｆとを備えている。外周部２３Ｄは、平面視において、第１ダイアフラム２３Ｂと、第２ダイアフラム２３Ｃと、連通部２３Ｅ，２３Ｆとを囲んでいる。 As shown in FIG. 3, the conductive layer 23 includes a first diaphragm 23B, a second diaphragm 23C, an outer peripheral portion 23D, and communication portions 23E and 23F. The outer peripheral portion 23D surrounds the first diaphragm 23B, the second diaphragm 23C, and the communication portions 23E and 23F in a plan view.
　第１ダイアフラム２３Ｂは、連通部２３Ｅを介してパッド２４Ａと電気的に接続されている。第２ダイアフラム２３Ｃは、連通部２３Ｆを介してパッド２４Ｂと電気的に接続されている。パッド２４Ａ，２４Ｂは、絶縁層２２の上面２２Ａに支持されている。第１ダイアフラム２３Ｂ及び連通部２３Ｅと第２ダイアフラム２３Ｃ及び連通部２３Ｆとは、外周部２３Ｄとの間に隙間を空けて形成されている。第１ダイアフラム２３Ｂ及び連通部２３Ｅは、外周部２３Ｄを介して第２ダイアフラム２３Ｃ及び連通部２３Ｆと隔てられている。 The first diaphragm 23B is electrically connected to the pad 24A via the communication portion 23E. The second diaphragm 23C is electrically connected to the pad 24B via the communication portion 23F. The pads 24A and 24B are supported by the upper surface 22A of the insulating layer 22. The first diaphragm 23B and the communication portion 23E and the second diaphragm 23C and the communication portion 23F are formed with a gap between the outer peripheral portion 23D. The first diaphragm 23B and the communication portion 23E are separated from the second diaphragm 23C and the communication portion 23F via the outer peripheral portion 23D.
　図２に示すように、第１ダイアフラム２３Ｂは、開口部２２Ｂを介して基台２１の上面２１Ｂと対向している。つまり、平面視において、第１ダイアフラム２３Ｂは、開口部２２Ｂと重複している。第２ダイアフラム２３Ｃは、開口部２２Ｃを介して基台２１の上面２１Ｂと対向している。つまり、平面視において、第２ダイアフラム２３Ｃは、開口部２２Ｃと重複している。 As shown in FIG. 2, the first diaphragm 23B faces the upper surface 21B of the base 21 via the opening 22B. That is, in a plan view, the first diaphragm 23B overlaps with the opening 22B. The second diaphragm 23C faces the upper surface 21B of the base 21 via the opening 22C. That is, in a plan view, the second diaphragm 23C overlaps with the opening 22C.
　第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃは、第１被覆部４０の開口部４１と、キャップ５１の内部空間５３とを介して、圧力センサ１の外部に露出されている。 The first diaphragm 23B and the second diaphragm 23C are exposed to the outside of the pressure sensor 1 via the opening 41 of the first covering portion 40 and the internal space 53 of the cap 51.
　図３に示すように、平面視において、第１ダイアフラム２３Ｂと第２ダイアフラム２３Ｃとは、同一形状且つ同一面積である。なお、平面視において、第１ダイアフラム２３Ｂと第２ダイアフラム２３Ｃとは、完全に同一形状である必要はなく、略同一形状であってもよい。また、平面視において、第１ダイアフラム２３Ｂと第２ダイアフラム２３Ｃとは、完全に同一面積である必要はなく、略同一面積であってもよい。また、平面視において、第１ダイアフラム２３Ｂと第２ダイアフラム２３Ｃとは、異なる形状であってもよいし、異なる面積であってもよい。 As shown in FIG. 3, in a plan view, the first diaphragm 23B and the second diaphragm 23C have the same shape and the same area. In a plan view, the first diaphragm 23B and the second diaphragm 23C do not have to have exactly the same shape, and may have substantially the same shape. Further, in a plan view, the first diaphragm 23B and the second diaphragm 23C do not have to have completely the same area, and may have substantially the same area. Further, in a plan view, the first diaphragm 23B and the second diaphragm 23C may have different shapes or different areas.
　図２に示すように、誘電体膜２６及びゲッター２７が、開口部２２Ｃに配置されている。 As shown in FIG. 2, the dielectric film 26 and the getter 27 are arranged in the opening 22C.
　誘電体膜２６は、基台２１の上面２１Ｂに支持されている。誘電体膜２６は、セラミック、プラスチック等の誘電体で構成されている。誘電体膜２６の高さ方向４の長さは、絶縁層２２の高さ方向４の長さより短い。言い換えると、誘電体膜２６の厚みＴ１は、絶縁層２２の厚みＴ２より薄い。そのため、誘電体膜２６の上面２６Ａと、第２ダイアフラム２３Ｃの下面２３Ｃａとの間には、隙間がある。 The dielectric film 26 is supported by the upper surface 21B of the base 21. The dielectric film 26 is made of a dielectric such as ceramic or plastic. The length of the dielectric film 26 in the height direction 4 is shorter than the length of the insulating layer 22 in the height direction 4. In other words, the thickness T1 of the dielectric film 26 is thinner than the thickness T2 of the insulating layer 22. Therefore, there is a gap between the upper surface 26A of the dielectric film 26 and the lower surface 23Ca of the second diaphragm 23C.
　ゲッター２７は、基台２１の上面２１Ｂに支持されている。ゲッター２７は、開口部２２Ｃ内のガス（例えば、酸素、窒素、二酸化炭素等）を吸収する吸着剤である。第１実施形態において、ゲッター２７は、チタンで構成されている。なお、ゲッター２７はチタン以外、例えばトリウム、バナジウム、またはマグネシウム等で構成されていてもよい。 The getter 27 is supported by the upper surface 21B of the base 21. The getter 27 is an adsorbent that absorbs gas (for example, oxygen, nitrogen, carbon dioxide, etc.) in the opening 22C. In the first embodiment, the getter 27 is made of titanium. The getter 27 may be made of, for example, thorium, vanadium, magnesium, or the like, in addition to titanium.
　第１実施形態において、ゲッター２７は、平面視において、誘電体膜２６を囲むように配置されている。言い換えると、ゲッター２７は、平面視において、誘電体膜２６と絶縁層２２の側面２２Ｄとの間に配置されている。更に言い換えると、平面視におけるゲッター２７と開口部２２Ｃの中心部２２Ｃａとの距離Ｄ１は、平面視における誘電体膜２６と開口部２２Ｃの中心部２２Ｃａとの距離より長い。図２において、誘電体膜２６は、開口部２２Ｃの中心部２２Ｃａを含んでいる。そのため、平面視における誘電体膜２６と開口部２２Ｃの中心部２２Ｃａとの距離はゼロである。 In the first embodiment, the getter 27 is arranged so as to surround the dielectric film 26 in a plan view. In other words, the getter 27 is arranged between the dielectric film 26 and the side surface 22D of the insulating layer 22 in a plan view. In other words, the distance D1 between the getter 27 and the central portion 22Ca of the opening 22C in the plan view is longer than the distance D1 between the dielectric film 26 and the central portion 22Ca of the opening 22C in the plan view. In FIG. 2, the dielectric film 26 includes the central portion 22Ca of the opening 22C. Therefore, the distance between the dielectric film 26 and the central portion 22Ca of the opening 22C in a plan view is zero.
　なお、誘電体膜２６は、図２に破線で示すように、開口部２２Ｃの中心部２２Ｃａから外れた位置に配置されていてもよい。このような場合、第１実施形態では、平面視における誘電体膜２６と開口部２２Ｃの中心部２２Ｃａとの距離Ｄ２は、距離Ｄ１より短い。 The dielectric film 26 may be arranged at a position away from the central portion 22Ca of the opening 22C, as shown by the broken line in FIG. In such a case, in the first embodiment, the distance D2 between the dielectric film 26 and the central portion 22Ca of the opening 22C in a plan view is shorter than the distance D1.
　ゲッター２７の高さ方向４の長さは、誘電体膜２６の高さ方向４の長さより短い。言い換えると、ゲッター２７の厚みＴ３は、誘電体膜２６の厚みＴ１より薄い。 The length of the getter 27 in the height direction 4 is shorter than the length of the dielectric film 26 in the height direction 4. In other words, the thickness T3 of the getter 27 is thinner than the thickness T1 of the dielectric film 26.
　図２に示すように、誘電体膜２８が、開口部２２Ｂに配置されている。誘電体膜２８は、基台２１の上面２１Ｂに支持されている。誘電体膜２８は、セラミック、プラスチック等の誘電体で構成されている。誘電体膜２８の高さ方向４の長さは、誘電体膜２６の高さ方向４の長さより短い。なお、開口部２２Ｂに誘電体膜２８が配置されていなくてもよい。つまり、圧力センサ用チップ２０は、誘電体膜２８を備えていなくてもよい。 As shown in FIG. 2, the dielectric film 28 is arranged in the opening 22B. The dielectric film 28 is supported by the upper surface 21B of the base 21. The dielectric film 28 is made of a dielectric such as ceramic or plastic. The length of the dielectric film 28 in the height direction 4 is shorter than the length of the dielectric film 26 in the height direction 4. The dielectric film 28 may not be arranged in the opening 22B. That is, the pressure sensor chip 20 does not have to include the dielectric film 28.
　図４は、図２の圧力センサ用チップの等価回路を示す図である。 FIG. 4 is a diagram showing an equivalent circuit of the pressure sensor chip of FIG. 2.
　図２に示すように、いずれも導電体である基台２１及び第１ダイアフラム２３Ｂは、開口部２２Ｂ及び開口部２２Ｂに配置された誘電体膜２８を介して互いに対向している。よって、基台２１及び第１ダイアフラム２３Ｂによって、開口部２２ＢにコンデンサＣ１（図４参照）が形成されている。また、いずれも導電体である基台２１及び第２ダイアフラム２３Ｃは、開口部２２Ｃ及び開口部２２Ｃに配置された誘電体膜２６を介して互いに対向している。よって、基台２１及び第２ダイアフラム２３Ｃによって、開口部２２ＣにコンデンサＣ２（図４参照）が形成されている。上記の場合、基台２１、第１ダイアフラム２３Ｂ、及び第２ダイアフラム２３Ｃは、コンデンサの電極として機能する。 As shown in FIG. 2, the base 21 and the first diaphragm 23B, both of which are conductors, face each other via the dielectric film 28 arranged in the opening 22B and the opening 22B. Therefore, the capacitor C1 (see FIG. 4) is formed in the opening 22B by the base 21 and the first diaphragm 23B. Further, the base 21 and the second diaphragm 23C, both of which are conductors, face each other via the opening 22C and the dielectric film 26 arranged in the opening 22C. Therefore, the capacitor C2 (see FIG. 4) is formed in the opening 22C by the base 21 and the second diaphragm 23C. In the above case, the base 21, the first diaphragm 23B, and the second diaphragm 23C function as electrodes of the capacitor.
　図５は、ダイアフラムに作用する圧力に対する開口部に形成されたコンデンサの容量値を示すグラフである。 FIG. 5 is a graph showing the capacitance value of the capacitor formed in the opening with respect to the pressure acting on the diaphragm.
　以下、第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する圧力が大気圧以下の値から高くなる場合の、当該圧力に対するコンデンサＣ１，Ｃ２の容量値の変化が、図５が参照されつつ説明される。図５において、横軸は、第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する圧力（単位：ｋＰａ）を示し、縦軸は、各コンデンサＣ１，Ｃ２の容量値（単位：ａＦ）を示す。コンデンサＣ１の特性は実線で示され、コンデンサＣ２の特性は一点鎖線で示される。 Hereinafter, when the pressure acting on the first diaphragm 23B and the second diaphragm 23C increases from the value below the atmospheric pressure, the change in the capacitance values of the capacitors C1 and C2 with respect to the pressure will be described with reference to FIG. .. In FIG. 5, the horizontal axis shows the pressure (unit: kPa) acting on the first diaphragm 23B and the second diaphragm 23C, and the vertical axis shows the capacitance value (unit: aF) of each of the capacitors C1 and C2. The characteristics of the capacitor C1 are shown by the solid line, and the characteristics of the capacitor C2 are shown by the alternate long and short dash line.
　図１に示すキャップ５１が管等に接続されることによって、流体がキャップ５１に取り込み可能である。この場合、流体による圧力は、キャップ５１の内部空間５３（図１参照）から第１被覆部４０の開口部４１（図１及び図２参照）を介して第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する。これにより、第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃは、下方へ撓む。第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する圧力が大きい程、第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃの撓み量は大きくなる。 By connecting the cap 51 shown in FIG. 1 to a pipe or the like, the fluid can be taken into the cap 51. In this case, the pressure due to the fluid is applied from the internal space 53 of the cap 51 (see FIG. 1) to the first diaphragm 23B and the second diaphragm 23C through the opening 41 (see FIGS. 1 and 2) of the first covering portion 40. It works. As a result, the first diaphragm 23B and the second diaphragm 23C bend downward. The greater the pressure acting on the first diaphragm 23B and the second diaphragm 23C, the greater the amount of deflection of the first diaphragm 23B and the second diaphragm 23C.
　第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃの撓み量が小さいとき（図５における圧力範囲ＰＲ１のとき）、第１ダイアフラム２３Ｂは誘電体膜２８から離れており、第２ダイアフラム２３Ｃは誘電体膜２６から離れている。 When the amount of deflection of the first diaphragm 23B and the second diaphragm 23C is small (when the pressure range PR1 in FIG. 5), the first diaphragm 23B is separated from the dielectric film 28, and the second diaphragm 23C is separated from the dielectric film 26. is seperated.
　この場合、第１ダイアフラム２３Ｂが撓んでいない状態（図１に示す状態）のときより、第１ダイアフラム２３Ｂと基台２１との間の距離は小さくなるため、コンデンサＣ１の容量値は、図１に示す状態のときより大きくなる。また、この場合、第２ダイアフラム２３Ｃが撓んでいない状態（図１に示す状態）のときより、第２ダイアフラム２３Ｃと基台２１との間の距離は小さくなるため、コンデンサＣ２の容量値は、図１に示す状態のときより大きくなる。 In this case, since the distance between the first diaphragm 23B and the base 21 is smaller than when the first diaphragm 23B is not bent (the state shown in FIG. 1), the capacitance value of the capacitor C1 is shown in FIG. It becomes larger than the state shown in. Further, in this case, since the distance between the second diaphragm 23C and the base 21 is smaller than when the second diaphragm 23C is not bent (the state shown in FIG. 1), the capacitance value of the capacitor C2 is set. It is larger than that in the state shown in FIG.
　このとき、コンデンサＣ１の容量値の第１ダイアフラム２３Ｂに作用する圧力に対する関係と、コンデンサＣ２の容量値の第２ダイアフラム２３Ｃに作用する圧力に対する関係とは、Ｃ＝ε（ｄ／Ｓ）の式に従う。この式において、Ｃはコンデンサの容量値であり、ｄはコンデンサを構成する電極間の距離であり、Ｓはコンデンサを構成する電極の面積であり、εは対向する電極間に存在する物質の誘電率である。コンデンサＣ１を構成する２つの電極（第１ダイアフラム２３Ｂ及び基台２１）の間に存在する物質は、開口部２２Ｂに存在する空気等の気体、及び誘電体膜２８である。コンデンサＣ２を構成する２つの電極（第２ダイアフラム２３Ｃ及び基台２１）の間に存在する物質は、開口部２２Ｃに存在する空気等の気体、及び誘電体膜２６である。第１実施形態では、誘電体膜２６は誘電体膜２６より高さ方向４に長い。そのため、コンデンサＣ２の容量値は、コンデンサＣ１の容量値より大きい。 At this time, the relationship between the capacitance value of the capacitor C1 with respect to the pressure acting on the first diaphragm 23B and the relationship between the capacitance value of the capacitor C2 with respect to the pressure acting on the second diaphragm 23C is an equation of C = ε (d / S). Follow. In this equation, C is the capacitance value of the capacitor, d is the distance between the electrodes constituting the capacitor, S is the area of the electrodes constituting the capacitor, and ε is the dielectric constant of the substance existing between the opposing electrodes. The rate. The substances existing between the two electrodes (the first diaphragm 23B and the base 21) constituting the capacitor C1 are a gas such as air existing in the opening 22B and the dielectric film 28. The substances existing between the two electrodes (second diaphragm 23C and base 21) constituting the capacitor C2 are a gas such as air existing in the opening 22C and the dielectric film 26. In the first embodiment, the dielectric film 26 is longer in the height direction 4 than the dielectric film 26. Therefore, the capacitance value of the capacitor C2 is larger than the capacitance value of the capacitor C1.
　第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに更に大きな圧力が作用することによって、第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃの撓み量が大きくなると、第２ダイアフラム２３Ｃが誘電体膜２６の上面２６Ａに接触する。このとき、コンデンサＣ２の容量値は、急激に増加する。つまり、このとき、コンデンサＣ２の容量値の、第２ダイアフラム２３Ｃに作用する圧力に対する関係は、非線形となる。このとき、第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する圧力は、第２接触圧力ＰＣ２である。 When a larger pressure acts on the first diaphragm 23B and the second diaphragm 23C and the amount of deflection of the first diaphragm 23B and the second diaphragm 23C increases, the second diaphragm 23C comes into contact with the upper surface 26A of the dielectric film 26. .. At this time, the capacitance value of the capacitor C2 increases sharply. That is, at this time, the relationship between the capacitance value of the capacitor C2 and the pressure acting on the second diaphragm 23C becomes non-linear. At this time, the pressure acting on the first diaphragm 23B and the second diaphragm 23C is the second contact pressure PC2.
　なお、開口部２２Ｂにおける誘電体膜２８の上面２８Ａと第１ダイアフラム２３Ｂとの間隔（高さ方向４の長さ）は、開口部２２Ｃにおける誘電体膜２６の上面２６Ａと第２ダイアフラム２３Ｃとの間隔（高さ方向４の長さ）よりも長い。そのため、第２ダイアフラム２３Ｃが誘電体膜２６の上面２６Ａに接触したとき、第１ダイアフラム２３Ｂは誘電体膜２８の上面２８Ａに接触していない。そのため、コンデンサＣ１の容量値の、第１ダイアフラム２３Ｂに作用する圧力に対する関係は、依然として前述した式に従う。 The distance (length in the height direction 4) between the upper surface 28A of the dielectric film 28 and the first diaphragm 23B in the opening 22B is the distance between the upper surface 26A and the second diaphragm 23C of the dielectric film 26 in the opening 22C. It is longer than the interval (length in the height direction 4). Therefore, when the second diaphragm 23C is in contact with the upper surface 26A of the dielectric film 26, the first diaphragm 23B is not in contact with the upper surface 28A of the dielectric film 28. Therefore, the relationship between the capacitance value of the capacitor C1 and the pressure acting on the first diaphragm 23B still follows the above-mentioned equation.
　第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用に更に大きな圧力が作用したとき（図５における圧力範囲ＰＲ２のとき）、誘電体膜２６の上面２６Ａに対する第２ダイアフラム２３Ｃの接触面積が大きくなる。前記の接触面積が大きくなるにしたがって、コンデンサＣ２の容量値は大きくなる。このとき、コンデンサＣ２の容量値の、第２ダイアフラム２３Ｃに作用する圧力に対する関係は、概ね線形となる。なお、このとき、第１ダイアフラム２３Ｂの撓み量が更に大きくなるにしたがって、第１ダイアフラム２３Ｂと基台２１との間の距離は小さくなる。そのため、コンデンサＣ１の容量値は、第１ダイアフラム２３Ｂに作用する圧力に対して前述した式に従いつつ大きくなる。 When a larger pressure is applied to the first diaphragm 23B and the second diaphragm 23C (in the pressure range PR2 in FIG. 5), the contact area of the second diaphragm 23C with respect to the upper surface 26A of the dielectric film 26 becomes large. As the contact area increases, the capacitance value of the capacitor C2 increases. At this time, the relationship between the capacitance value of the capacitor C2 and the pressure acting on the second diaphragm 23C is approximately linear. At this time, as the amount of deflection of the first diaphragm 23B becomes larger, the distance between the first diaphragm 23B and the base 21 becomes smaller. Therefore, the capacitance value of the capacitor C1 increases with respect to the pressure acting on the first diaphragm 23B according to the above-mentioned equation.
　第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用に更に大きな圧力が作用することによって、第１ダイアフラム２３Ｂの撓み量が大きくなると、第１ダイアフラム２３Ｂが誘電体膜２８の上面２８Ａに接触する。このとき、コンデンサＣ１の容量値は、急激に増加する。つまり、このとき、コンデンサＣ１の容量値の、第１ダイアフラム２３Ｂに作用する圧力に対する関係は、非線形となる。このとき、第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する圧力は、第１接触圧力ＰＣ１である。なお、このとき、コンデンサＣ２の容量値の、第２ダイアフラム２３Ｃに作用する圧力に対する関係は、線形を維持している。 When the amount of deflection of the first diaphragm 23B increases due to a larger pressure acting on the first diaphragm 23B and the second diaphragm 23C, the first diaphragm 23B comes into contact with the upper surface 28A of the dielectric film 28. At this time, the capacitance value of the capacitor C1 increases sharply. That is, at this time, the relationship between the capacitance value of the capacitor C1 and the pressure acting on the first diaphragm 23B becomes non-linear. At this time, the pressure acting on the first diaphragm 23B and the second diaphragm 23C is the first contact pressure PC1. At this time, the relationship between the capacitance value of the capacitor C2 and the pressure acting on the second diaphragm 23C maintains a linear shape.
　なお、圧力センサ用チップ２０が誘電体膜２８を備えていない場合、つまり開口部２２Ｂに誘電体膜２８が配置されていない場合、前述したように第１ダイアフラム２３Ｂの撓み量が大きくなると、第１ダイアフラム２３Ｂが基台２１の上面２１Ｂに接触する。このとき、コンデンサＣ１の容量値は、急激に減少する。 When the pressure sensor chip 20 does not have the dielectric film 28, that is, when the dielectric film 28 is not arranged in the opening 22B, when the amount of deflection of the first diaphragm 23B becomes large as described above, the first diaphragm 23B is used. 1 The diaphragm 23B comes into contact with the upper surface 21B of the base 21. At this time, the capacitance value of the capacitor C1 decreases sharply.
　第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに更に大きな圧力が作用したとき（図５における圧力範囲ＰＲ３のとき）、誘電体膜２８の上面２８Ａに対する第１ダイアフラム２３Ｂの接触面積が大きくなる。前記の接触面積が大きくなるにしたがって、コンデンサＣ１の容量値は大きくなる。このとき、コンデンサＣ１の容量値の、第１ダイアフラム２３Ｂに作用する圧力に対する関係は、概ね線形となる。なお、このとき、誘電体膜２６の上面２６Ａに対する第２ダイアフラム２３Ｃの接触面積も更に大きくなるため、コンデンサＣ２の容量値も、第２ダイアフラム２３Ｃに作用する圧力に対して概ね線形を維持しつつ大きくなる。 When a larger pressure is applied to the first diaphragm 23B and the second diaphragm 23C (in the pressure range PR3 in FIG. 5), the contact area of the first diaphragm 23B with respect to the upper surface 28A of the dielectric film 28 becomes large. As the contact area increases, the capacitance value of the capacitor C1 increases. At this time, the relationship between the capacitance value of the capacitor C1 and the pressure acting on the first diaphragm 23B is generally linear. At this time, since the contact area of the second diaphragm 23C with respect to the upper surface 26A of the dielectric film 26 is further increased, the capacitance value of the capacitor C2 also maintains a substantially linearity with respect to the pressure acting on the second diaphragm 23C. growing.
　第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する圧力が大気圧より高い値から低くなる場合の、当該圧力に対するコンデンサＣ１，Ｃ２の容量値の変化も、図５に従う。 When the pressure acting on the first diaphragm 23B and the second diaphragm 23C becomes lower than the atmospheric pressure, the change in the capacitance values of the capacitors C1 and C2 with respect to the pressure also follows FIG.
　つまり、図５における圧力範囲ＰＲ３の圧力（大気圧より高い値の圧力）が第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用すると、第１ダイアフラム２３Ｂが誘電体膜２８に接触し、第２ダイアフラム２３Ｃが誘電体膜２６に接触する。 That is, when the pressure in the pressure range PR3 (pressure higher than the atmospheric pressure) in FIG. 5 acts on the first diaphragm 23B and the second diaphragm 23C, the first diaphragm 23B comes into contact with the dielectric film 28 and the second diaphragm 23C. Contact the dielectric film 26.
　その後、第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する圧力が低くなると、第１ダイアフラム２３Ｂの誘電体膜２８に対する接触面積と、第２ダイアフラム２３Ｃの誘電体膜２６に対する接触面積とが減少する。このとき、コンデンサＣ１の容量値の第１ダイアフラム２３Ｂに作用する圧力に対する関係と、コンデンサＣ２の容量値の第２ダイアフラム２３Ｃに作用する圧力に対する関係とは、共に概ね線形となる。 After that, when the pressure acting on the first diaphragm 23B and the second diaphragm 23C becomes low, the contact area of the first diaphragm 23B with respect to the dielectric film 28 and the contact area of the second diaphragm 23C with respect to the dielectric film 26 decrease. At this time, the relationship between the capacitance value of the capacitor C1 and the pressure acting on the first diaphragm 23B and the relationship between the capacitance value of the capacitor C2 and the pressure acting on the second diaphragm 23C are both substantially linear.
　第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する圧力が第１接触圧力ＰＣ１まで低くなると、第１ダイアフラム２３Ｂが誘電体膜２８から離れる。このとき、コンデンサＣ１の容量値は、急激に減少する。 When the pressure acting on the first diaphragm 23B and the second diaphragm 23C becomes as low as the first contact pressure PC1, the first diaphragm 23B separates from the dielectric film 28. At this time, the capacitance value of the capacitor C1 decreases sharply.
　第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する圧力が圧力範囲ＰＲ２のとき、第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する圧力が低くなると、第１ダイアフラム２３Ｂの誘電体膜２８に対する間隔が増加し、第２ダイアフラム２３Ｃの誘電体膜２６に対する接触面積が減少する。このとき、コンデンサＣ１の容量値の第１ダイアフラム２３Ｂに作用する圧力に対する関係は前述した式に従い、コンデンサＣ２の容量値の第２ダイアフラム２３Ｃに作用する圧力に対する関係は概ね線形となる。 When the pressure acting on the first diaphragm 23B and the second diaphragm 23C is in the pressure range PR2, when the pressure acting on the first diaphragm 23B and the second diaphragm 23C becomes low, the distance between the first diaphragm 23B and the dielectric film 28 increases. Then, the contact area of the second diaphragm 23C with respect to the dielectric film 26 is reduced. At this time, the relationship between the capacitance value of the capacitor C1 and the pressure acting on the first diaphragm 23B follows the above-mentioned equation, and the relationship between the capacitance value of the capacitor C2 and the pressure acting on the second diaphragm 23C is almost linear.
　第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する圧力が第２接触圧力ＰＣ２まで低くなると、第２ダイアフラム２３Ｃが誘電体膜２６から離れる。このとき、コンデンサＣ２の容量値は、急激に減少する。 When the pressure acting on the first diaphragm 23B and the second diaphragm 23C becomes as low as the second contact pressure PC2, the second diaphragm 23C separates from the dielectric film 26. At this time, the capacitance value of the capacitor C2 decreases sharply.
　第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する圧力が圧力範囲ＰＲ１のとき、第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用される圧力が低くなると、第１ダイアフラム２３Ｂの誘電体膜２８に対する間隔と、第２ダイアフラム２３Ｃの誘電体膜２６に対する間隔とが共に増加する。このとき、コンデンサＣ１の容量値の第１ダイアフラム２３Ｂに作用する圧力に対する関係と、コンデンサＣ２の容量値の第２ダイアフラム２３Ｃに作用する圧力に対する関係とは、共に前述した式に従う。 When the pressure acting on the first diaphragm 23B and the second diaphragm 23C is in the pressure range PR1, when the pressure acting on the first diaphragm 23B and the second diaphragm 23C becomes low, the distance between the first diaphragm 23B and the dielectric film 28 , The spacing of the second diaphragm 23C with respect to the dielectric film 26 increases together. At this time, the relationship between the capacitance value of the capacitor C1 with respect to the pressure acting on the first diaphragm 23B and the relationship between the capacitance value of the capacitor C2 with respect to the pressure acting on the second diaphragm 23C both follow the above-mentioned equations.
　ＡＳＩＣ３０は、３本のワイヤ３１を介して圧力センサ用チップ２０のパッド２４Ａ～２４Ｃと接続されている。つまり、ＡＳＩＣ３０は、基台２１、第１ダイアフラム２３Ｂ、及び第２ダイアフラム２３Ｃと電気的に接続されている。 The ASIC 30 is connected to the pads 24A to 24C of the pressure sensor chip 20 via three wires 31. That is, the ASIC 30 is electrically connected to the base 21, the first diaphragm 23B, and the second diaphragm 23C.
　上述したように、ＡＳＩＣ３０は、圧力センサ用チップ２０からワイヤ３１を介して入力された信号を処理して算出した圧力情報を、ワイヤ３２を介して外部へ出力する圧力測定の機能を有する。 As described above, the ASIC 30 has a pressure measurement function of processing pressure information calculated by processing a signal input from the pressure sensor chip 20 via the wire 31 and outputting the pressure information to the outside via the wire 32.
　図６は、圧力測定処理を示すフローチャートである。以下、図６に基づいて、圧力測定処理が説明される。 FIG. 6 is a flowchart showing the pressure measurement process. Hereinafter, the pressure measurement process will be described with reference to FIG.
　ＡＳＩＣ３０は、圧力測定処理の開始から終了まで、後述するステップＳ５０が繰り返し実行されることによって、コンデンサＣ１の容量値Ｃ１ｎ、及びコンデンサＣ２の容量値Ｃ２ｎを連続的にモニタリングする。ＡＳＩＣ３０は、コンデンサＣ１の容量値Ｃ１ｎ、及びコンデンサＣ２の容量値Ｃ２ｎを、基台２１、第１ダイアフラム２３Ｂ、及び第２ダイアフラム２３Ｃからの電流値や、基台２１、第１ダイアフラム２３Ｂ、及び第２ダイアフラム２３Ｃに印加される電圧値に基づいて算出する。 The ASIC 30 continuously monitors the capacitance value C1 n of the capacitor C1 and the capacitance value C2 n of the capacitor C2 by repeatedly executing step S50 described later from the start to the end of the pressure measurement process. The ASIC 30 sets the capacitance value C1 n of the capacitor C1 and the capacitance value C2 n of the capacitor C2 to the current values from the base 21, the first diaphragm 23B, and the second diaphragm 23C, and the base 21, the first diaphragm 23B, and so on. And, it is calculated based on the voltage value applied to the second diaphragm 23C.
　連続的にモニタリングとは、途切れなくモニタリングすることのみならず、短時間毎にモニタリングすることも含む。第１実施形態では、ＡＳＩＣ３０は、コンデンサＣ１，Ｃ２の容量値Ｃ１ｎ，Ｃ２ｎを単位時間毎にモニタリングする。単位時間は、コンデンサＣ１，Ｃ２の容量値Ｃ１ｎ，Ｃ２ｎと、第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する圧力との関係が非線形であるか否かを識別可能な程度に短く設定される。単位時間は、例えば５（ｍｓ）～１００（ｍｓ）の間で設定される。コンデンサＣ１，Ｃ２の容量値Ｃ１ｎ，Ｃ２ｎ及び後述する圧力情報（第１圧力情報Ｐ１ｎ及び第２圧力情報Ｐ２ｎ）において、ｎは自然数である。例えば、圧力測定処理の開始からｉ番目にモニタリングされたコンデンサＣ１の容量値は、Ｃ１ｉと示され、ｉ＋１番目にモニタリングされたコンデンサＣ２の容量値は、Ｃ２ｉ＋１と示される。コンデンサＣ１の容量値Ｃ１ｎは、第１値の一例である。コンデンサＣ２の容量値Ｃ２ｎは、第２値の一例である。 Continuous monitoring includes not only continuous monitoring but also short-time monitoring. In the first embodiment, the ASIC 30 monitors the capacitance values C1 n and C2 n of the capacitors C1 and C2 every unit time. The unit time is set short enough to discriminate whether or not the relationship between the capacitance values C1 n and C2 n of the capacitors C1 and C2 and the pressure acting on the first diaphragm 23B and the second diaphragm 23C is non-linear. To. The unit time is set, for example, between 5 (ms) and 100 (ms). In the capacitance values C1 n and C2 n of the capacitors C1 and C2 and the pressure information described later (first pressure information P1 n and second pressure information P2 n ), n is a natural number. For example, the capacitance value of the capacitor C1 monitored i-th from the start of the pressure measurement process is indicated as C1 i , and the capacitance value of the capacitor C2 monitored i + 1th is indicated as C2 i + 1 . The capacitance value C1 n of the capacitor C1 is an example of the first value. The capacitance value C2 n of the capacitor C2 is an example of the second value.
　ＡＳＩＣ３０は、圧力測定が開始されると、上記のモニタリングを開始する（Ｓ１０）。ＡＳＩＣ３０は、圧力測定の開始からの初期期間にモニタリングされたコンデンサＣ１の容量値Ｃ１ｎ（例えば、１つの容量値Ｃ１１や複数の容量値Ｃ１１～Ｃ１５等）、及びコンデンサＣ２の容量値Ｃ２ｎの少なくとも一方に基づいて、第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する圧力が大気圧より高いか否かを判定する（Ｓ２０）。 When the pressure measurement is started, the ASIC 30 starts the above monitoring (S10). The ASIC 30 has a capacitance value C1 n of the capacitor C1 monitored in the initial period from the start of the pressure measurement (for example, one capacitance value C1 1 or a plurality of capacitance values C1 1 to C1 5 etc.), and a capacitance value of the capacitor C2. Based on at least one of C2 n , it is determined whether or not the pressure acting on the first diaphragm 23B and the second diaphragm 23C is higher than the atmospheric pressure (S20).
　当該圧力が大気圧より高いと判定した場合（Ｓ２０：ｙｅｓ）、ＡＳＩＣ３０は、フラグをＯＮに設定する（Ｓ３０）。当該圧力が大気圧より小さい場合（Ｓ２０：ｎｏ）、ＡＳＩＣ３０は、フラグをＯＦＦに設定する（Ｓ４０）。なお、第１実施形態において、当該圧力が大気圧と等しい場合、ＡＳＩＣ３０は、フラグをＯＦＦに設定する。 When it is determined that the pressure is higher than the atmospheric pressure (S20: yes), the ASIC30 sets the flag to ON (S30). When the pressure is smaller than the atmospheric pressure (S20: no), the ASIC30 sets the flag to OFF (S40). In the first embodiment, when the pressure is equal to the atmospheric pressure, the ASIC 30 sets the flag to OFF.
　フラグは、ＡＳＩＣ３０内またはＡＳＩＣ３０外に設けられたメモリ（以下、単にメモリと記される。）に記憶されている。後述するように、フラグがＯＦＦのとき、ＡＳＩＣ３０は、コンデンサＣ１の容量値Ｃ１ｎに基づく第１圧力情報Ｐ１ｎを外部へ出力し、フラグがＯＮのとき、ＡＳＩＣ３０は、コンデンサＣ２の容量値Ｃ２ｎに基づく第２圧力情報Ｐ２ｎを外部へ出力する。 The flag is stored in a memory provided inside or outside the ASIC 30 (hereinafter, simply referred to as a memory). As will be described later, when the flag is OFF, the ASIC 30 outputs the first pressure information P1 n based on the capacitance value C1 n of the capacitor C1 to the outside, and when the flag is ON, the ASIC 30 is the capacitance value C2 of the capacitor C2. The second pressure information P2 n based on n is output to the outside.
　次に、ＡＳＩＣ３０は、コンデンサＣ１の容量値Ｃ１ｉ、及びコンデンサＣ２の容量値Ｃ２ｉをモニタリングする（Ｓ５０）。なお、ｉは、モニタリングの回数である。例えば、測定開始から９９番目にモニタリングされた容量値Ｃ１ｉの場合、ｉは９９である。 Next, the ASIC 30 monitors the capacitance value C1 i of the capacitor C1 and the capacitance value C2 i of the capacitor C2 (S50). In addition, i is the number of times of monitoring. For example, in the case of the capacitance value C1 i monitored 99th from the start of measurement, i is 99.
　次に、ＡＳＩＣ３０は、ステップＳ５０においてモニタリングした容量値Ｃ１ｉに基づいて第１圧力情報Ｐ１ｉを算出し、ステップＳ５０においてモニタリングした容量値Ｃ２ｉに基づいて第２圧力情報Ｐ２ｉを算出する（Ｓ６０）。つまり、複数の容量値Ｃ１ｎに対応して複数の第１圧力情報Ｐ１ｎが算出され、複数の容量値Ｃ２ｎに対応して複数の第２圧力情報Ｐ２ｎが算出される。 Next, the ASIC 30 calculates the first pressure information P1 i based on the capacity value C1 i monitored in step S50, and calculates the second pressure information P2 i based on the capacity value C2 i monitored in step S50 (. S60). That is, a plurality of first pressure information P1 n is calculated corresponding to the plurality of capacitance values C1 n , and a plurality of second pressure information P2 n is calculated corresponding to the plurality of capacitance values C2 n .
　第１圧力情報Ｐ１ｉを含む複数の第１圧力情報Ｐ１ｎは、第１ダイアフラム２３Ｂに作用する圧力に関する情報である。第２圧力情報Ｐ２ｉを含む複数の第２圧力情報Ｐ２ｎは、第２ダイアフラム２３Ｃに作用する圧力に関する情報である。例えば、第１圧力情報Ｐ１ｎ及び第２圧力情報Ｐ２ｎの各々は、圧力の大きさを示す数値情報である。また、例えば、第１圧力情報Ｐ１ｎ及び第２圧力情報Ｐ２ｎの各々は、対応する容量値Ｃ１ｎ，Ｃ２ｎと同値であってもよい。 The plurality of first pressure information P1 n including the first pressure information P1 i is information regarding the pressure acting on the first diaphragm 23B. The plurality of second pressure information P2 n including the second pressure information P2 i is information regarding the pressure acting on the second diaphragm 23C. For example, each of the first pressure information P1 n and the second pressure information P2 n is numerical information indicating the magnitude of the pressure. Further, for example, each of the first pressure information P1 n and the second pressure information P2 n may have the same values as the corresponding capacitance values C1 n and C2 n .
　次に、ＡＳＩＣ３０は、フラグ切替判定処理を実行する（Ｓ７０）。フラグ切替判定処理は、フラグをＯＦＦからＯＮへまたはＯＮからＯＦＦへ切り替える否かを判定する処理である。フラグ切替判定処理は、後に詳細に説明される。 Next, the ASIC 30 executes the flag switching determination process (S70). The flag switching determination process is a process of determining whether or not to switch the flag from OFF to ON or from ON to OFF. The flag switching determination process will be described in detail later.
　次に、ＡＳＩＣ３０は、メモリに記憶されているフラグを参照する（Ｓ８０）。フラグがＯＮの場合（Ｓ８０：ｙｅｓ）、ＡＳＩＣ３０は、第２圧力情報Ｐ２ｉを外部へ出力する（Ｓ９０）。フラグがＯＦＦの場合（Ｓ８０：ｎｏ）、ＡＳＩＣ３０は、第１圧力情報Ｐ１ｉを外部へ出力する（Ｓ１００）。外部は、例えば圧力センサ１が接続される電子機器の表示部である。この表示部に、第１圧力情報Ｐ１ｉまたは第２圧力情報Ｐ２ｉに対応する圧力値が表示される。 Next, the ASIC 30 refers to the flag stored in the memory (S80). When the flag is ON (S80: yes), the ASIC 30 outputs the second pressure information P2 i to the outside (S90). When the flag is OFF (S80: no), the ASIC 30 outputs the first pressure information P1 i to the outside (S100). The outside is, for example, a display unit of an electronic device to which the pressure sensor 1 is connected. The pressure value corresponding to the first pressure information P1 i or the second pressure information P2 i is displayed on this display unit.
　第１実施形態では、第１圧力情報Ｐ１ｎ及び第２圧力情報Ｐ２ｎの算出は、各容量値Ｃ１ｎ，Ｃ２ｎがモニタリングされる度に、逐次的に実行される。しかし、当該算出は、所定数の容量値Ｃ１ｎ，Ｃ２ｎがモニタリングされる度に、一括して実行されてもよい。 In the first embodiment, the calculation of the first pressure information P1 n and the second pressure information P2 n is sequentially executed each time the capacitance values C1 n and C2 n are monitored. However, the calculation may be performed collectively every time a predetermined number of capacity values C1 n and C2 n are monitored.
　その後、圧力測定が終了されない場合（Ｓ１１０：ｎｏ）、ステップＳ５０～Ｓ１００が再び実行される。圧力測定は、例えば、外部からＡＳＩＣ３０への給電が停止されると終了される（Ｓ１１０：ｙｅｓ）。 After that, if the pressure measurement is not completed (S110: no), steps S50 to S100 are executed again. The pressure measurement is terminated, for example, when the power supply to the ASIC 30 from the outside is stopped (S110: yes).
　図７は、フラグ切替判定処理を示すフローチャートである。以下、図７に基づいて、図６におけるフラグ切替判定処理が説明される。 FIG. 7 is a flowchart showing the flag switching determination process. Hereinafter, the flag switching determination process in FIG. 6 will be described with reference to FIG. 7.
　最初に、ＡＳＩＣ３０は、メモリに記憶されているフラグを参照する（Ｓ２１０）。フラグがＯＦＦの場合（Ｓ２１０：ｎｏ）、ＡＳＩＣ３０は、以下に示すステップＳ２２０以降の処理を実行する。フラグがＯＮの場合（Ｓ２１０：ｙｅｓ）、ＡＳＩＣ３０は、後述するステップＳ３００以降の処理を実行する。 First, the ASIC 30 refers to the flag stored in the memory (S210). When the flag is OFF (S210: no), the ASIC 30 executes the processes after step S220 shown below. When the flag is ON (S210: yes), the ASIC 30 executes the processes after step S300, which will be described later.
　フラグがＯＦＦの場合（Ｓ２１０：ｎｏ）、ＡＳＩＣ３０は、コンデンサＣ２の容量値Ｃ２ｎの最新値である容量値Ｃ２ｉから、コンデンサＣ２の容量値Ｃ２ｎのうちの容量値Ｃ２ｉより単位時間前の直近の容量値Ｃ２ｉ－１を減算した値が設定値ＣＳより大きいか否かを判定する（Ｓ２２０）。 When the flag is OFF (S210: no), the ASIC 30 has a unit time before the capacity value C2 i of the capacity values C2 n of the capacitor C2 from the capacity value C2 i which is the latest value of the capacity value C2 n of the capacitor C2. It is determined whether or not the value obtained by subtracting the latest capacitance value C2 i-1 of is larger than the set value CS (S220).
　設定値ＣＳは、予め設定された値であり、メモリに記憶されている。設定値ＣＳは、コンデンサＣ２の容量値Ｃ２ｎと、第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する圧力との関係が非線形でないとき（前述の式に従うとき又は線形であるとき）のコンデンサＣ２の容量値Ｃ２ｎの最新値とコンデンサＣ２の容量値Ｃ２ｎの直近値との差より大きく、且つ当該関係が非線形であるときの当該最新値と当該直近値との差より小さい値に設定される。設定値ＣＳは、第２ダイアフラム２３Ｃの厚み（高さ方向４の長さ）や、第２ダイアフラム２３Ｃと誘電体膜２６との間隔等に基づいて設定される。 The set value CS is a preset value and is stored in the memory. The set value CS is the capacitor C2 when the relationship between the capacitance value C2 n of the capacitor C2 and the pressure acting on the first diaphragm 23B and the second diaphragm 23C is not non-linear (when according to the above equation or when it is linear). It is set to a value larger than the difference between the latest value of the capacitance value C2 n and the latest value of the capacitance value C2 n of the capacitor C2, and smaller than the difference between the latest value and the latest value when the relationship is non-linear. .. The set value CS is set based on the thickness of the second diaphragm 23C (the length in the height direction 4), the distance between the second diaphragm 23C and the dielectric film 26, and the like.
　容量値Ｃ２ｉから容量値Ｃ２ｉ－１を減算した値が設定値ＣＳより大きい場合（Ｓ２２０：ｙｅｓ）、ＡＳＩＣ３０は、容量値Ｃ２ｉに基づく第２圧力情報Ｐ２ｉを第２接触圧力情報ＰＣＩ２としてメモリに記憶する（Ｓ２３０）。第２接触圧力情報ＰＣＩ２は、第２ダイアフラム２３Ｃが誘電体膜２６の上面２６Ａに接触したときの圧力（第２接触圧力ＰＣ２（図５参照））に対応する情報である。 When the value obtained by subtracting the capacity value C2 i -1 from the capacity value C2 i is larger than the set value CS (S220: yes), the ASIC 30 sets the second pressure information P2 i based on the capacity value C2 i to the second contact pressure information PCI2. Is stored in the memory (S230). The second contact pressure information PCI2 is information corresponding to the pressure when the second diaphragm 23C comes into contact with the upper surface 26A of the dielectric film 26 (second contact pressure PC2 (see FIG. 5)).
　容量値Ｃ２ｉから容量値Ｃ２ｉ－１を減算した値が設定値ＣＳより小さい場合（Ｓ２２０：ｎｏ）、ＡＳＩＣ３０は、ステップＳ２３０を実行することなく、以下で説明するステップＳ２４０を実行する。なお、第１実施形態では、容量値Ｃ２ｉから容量値Ｃ２ｉ－１を減算した値が設定値ＣＳと等しい場合も、ＡＳＩＣ３０は、ステップＳ２３０を実行することなく、ステップＳ２４０を実行する。 When the value obtained by subtracting the capacity value C2 i -1 from the capacity value C2 i is smaller than the set value CS (S220: no), the ASIC 30 executes step S240 described below without executing step S230. In the first embodiment, even when the value obtained by subtracting the capacity value C2 i -1 from the capacity value C2 i is equal to the set value CS, the ASIC 30 executes step S240 without executing step S230.
　次に、ＡＳＩＣ３０は、コンデンサＣ１の容量値Ｃ１ｎの最新値である容量値Ｃ１ｉから、コンデンサＣ１の容量値Ｃ１ｎのうちの容量値Ｃ１ｉより単位時間前の直近の容量値Ｃ１ｉ－１を減算した値が設定値ＣＳより大きいか否かを判定する（Ｓ２４０）。 Next, the ASIC 30 has a capacitance value C1 i , which is the latest value of the capacitance value C1 n of the capacitor C1, and the latest capacitance value C1 i- It is determined whether or not the value obtained by subtracting 1 is larger than the set value CS (S240).
　設定値ＣＳは、予め設定された値であり、メモリに記憶されている。設定値ＣＳは、第１ダイアフラム２３Ｂの厚み（高さ方向４の長さ）や、第１ダイアフラム２３Ｂと誘電体膜２８との間隔等に基づいて設定される。第１実施形態において、ステップＳ２４０における設定値ＣＳは、ステップＳ２２０における設定値ＣＳと同一値であるが、ステップＳ２２０における設定値ＣＳと異なる値であってもよい。 The set value CS is a preset value and is stored in the memory. The set value CS is set based on the thickness of the first diaphragm 23B (length in the height direction 4), the distance between the first diaphragm 23B and the dielectric film 28, and the like. In the first embodiment, the set value CS in step S240 is the same value as the set value CS in step S220, but may be a value different from the set value CS in step S220.
　容量値Ｃ１ｉから容量値Ｃ１ｉ－１を減算した値が設定値ＣＳより小さい場合（Ｓ２４０：ｎｏ）、ＡＳＩＣ３０は、フラグ切替判定処理を終えて、測定処理のステップＳ８０以降の処理を実行する（図６参照）。 When the value obtained by subtracting the capacity value C1 i -1 from the capacity value C1 i is smaller than the set value CS (S240: no), the ASIC 30 finishes the flag switching determination process and executes the processing after step S80 of the measurement process. (See FIG. 6).
　容量値Ｃ１ｉから容量値Ｃ１ｉ－１を減算した値が設定値ＣＳより大きい場合（Ｓ２４０：ｙｅｓ）、ＡＳＩＣ３０は、容量値Ｃ１ｉに基づく第１圧力情報Ｐ１ｉを第１接触圧力情報ＰＣＩ１としてメモリに記憶する（Ｓ２５０）。第１接触圧力情報ＰＣＩ１は、第１ダイアフラム２３Ｂが基台２１の上面２１Ｂに接触したときの圧力（第１接触圧力ＰＣ１（図５参照））に対応する情報である。なお、第１実施形態では、容量値Ｃ１ｉから容量値Ｃ１ｉ－１を減算した値が設定値ＣＳと等しい場合も、ＡＳＩＣ３０はステップＳ２５０を実行する。 When the value obtained by subtracting the capacity value C1 i -1 from the capacity value C1 i is larger than the set value CS (S240: yes), the ASIC 30 sets the first pressure information P1 i based on the capacity value C1 i to the first contact pressure information PCI1. It is stored in the memory as (S250). The first contact pressure information PCI1 is information corresponding to the pressure when the first diaphragm 23B comes into contact with the upper surface 21B of the base 21 (first contact pressure PC1 (see FIG. 5)). In the first embodiment, the ASIC 30 executes step S250 even when the value obtained by subtracting the capacity value C1 i -1 from the capacity value C1 i is equal to the set value CS.
　次に、ＡＳＩＣ３０は、第２接触圧力情報ＰＣＩ２が既に決定されているか否か判定する（Ｓ２６０）。 Next, the ASIC 30 determines whether or not the second contact pressure information PCI2 has already been determined (S260).
　第２接触圧力情報ＰＣＩ２が決定されている場合（Ｓ２６０：ｙｅｓ）、つまり第１接触圧力情報ＰＣＩ１及び第２接触圧力情報ＰＣＩ２の双方が決定されている場合、ＡＳＩＣ３０は、第１接触圧力情報ＰＣＩ１が加算圧力情報より大きいか否かを判定する（Ｓ２７０）。加算圧力情報は、第２接触圧力情報ＰＣＩ２に第１設定圧力情報ＰＳ１を加算した情報である。つまり、加算圧力情報は、ＰＣＩ２＋ＰＳ１である。 When the second contact pressure information PCI2 is determined (S260: yes), that is, when both the first contact pressure information PCI1 and the second contact pressure information PCI2 are determined, the ASIC 30 determines the first contact pressure information PCI1. Is larger than the added pressure information (S270). The added pressure information is information obtained by adding the first set pressure information PS1 to the second contact pressure information PCI2. That is, the additional pressure information is PCI2 + PS1.
　第１設定圧力情報ＰＳ１は、第２ダイアフラム２３Ｃが誘電体膜２６の上面２６Ａに接触してから、第１ダイアフラム２３Ｂが誘電体膜２８の上面２８Ａに接触するまでに、第１ダイアフラム２３Ｂに加えることが必要な圧力、つまり第１接触圧力ＰＣ１と第２接触圧力ＰＣ２との圧力差に基づいて設定される情報である。第１設定圧力情報ＰＳ１は、第１ダイアフラム２３Ｂと誘電体膜２８の上面２８Ａとの間隔と、第２ダイアフラム２３Ｃと誘電体膜２６の上面２６Ａとの間隔との差や、第１ダイアフラム２３Ｂの厚み等に基づいて設定される。第１実施形態において、第１設定圧力情報ＰＳ１は、第１接触圧力ＰＣ１と第２接触圧力ＰＣ２との圧力差より少し小さな圧力差に対応した値に設定されている。 The first set pressure information PS1 is added to the first diaphragm 23B from the time when the second diaphragm 23C comes into contact with the upper surface 26A of the dielectric film 26 until the first diaphragm 23B comes into contact with the upper surface 28A of the dielectric film 28. This is information set based on the required pressure, that is, the pressure difference between the first contact pressure PC1 and the second contact pressure PC2. The first set pressure information PS1 is the difference between the distance between the first diaphragm 23B and the upper surface 28A of the dielectric film 28 and the distance between the second diaphragm 23C and the upper surface 26A of the dielectric film 26, and the first diaphragm 23B. It is set based on the thickness and the like. In the first embodiment, the first set pressure information PS1 is set to a value corresponding to a pressure difference slightly smaller than the pressure difference between the first contact pressure PC1 and the second contact pressure PC2.
　第１接触圧力情報ＰＣＩ１が加算圧力情報（ＰＣＩ２＋ＰＳ１）より大きい場合（Ｓ２７０：ｙｅｓ）、ＡＳＩＣ３０は、フラグをＯＮに設定する（Ｓ２８０）。なお、第１実施形態では、第１接触圧力情報ＰＣＩ１が加算圧力情報（ＰＣＩ２＋ＰＳ１）と同値である場合も、ＡＳＩＣ３０は、フラグをＯＮに設定する（Ｓ２８０）。 When the first contact pressure information PCI1 is larger than the added pressure information (PCI2 + PS1) (S270: yes), the ASIC30 sets the flag to ON (S280). In the first embodiment, the ASIC 30 sets the flag to ON even when the first contact pressure information PCI1 has the same value as the added pressure information (PCI2 + PS1) (S280).
　ステップＳ２６０において、第２接触圧力情報ＰＣＩ２が決定されていない場合（Ｓ２６０：ｎｏ）、直前のステップＳ２５０において第１接触圧力情報ＰＣＩ１が決定されている一方で、第２接触圧力情報ＰＣＩ２が決定されていない。この場合、ＡＳＩＣ３０は異常を示す情報を外部へ出力し（Ｓ２９０）、圧力の測定が終了される。 When the second contact pressure information PCI2 is not determined in step S260 (S260: no), the first contact pressure information PCI1 is determined in the immediately preceding step S250, while the second contact pressure information PCI2 is determined. Not. In this case, the ASIC 30 outputs information indicating an abnormality to the outside (S290), and the pressure measurement is completed.
　また、ステップＳ２７０において、第１接触圧力情報ＰＣＩ１が加算圧力情報（ＰＣＩ２＋ＰＳ１）より小さい場合（Ｓ２７０：ｎｏ）、ＡＳＩＣ３０は異常を示す情報を外部へ出力して（Ｓ２９０）、圧力の測定が終了される。 Further, in step S270, when the first contact pressure information PCI1 is smaller than the added pressure information (PCI2 + PS1) (S270: no), the ASIC 30 outputs information indicating an abnormality to the outside (S290), and the pressure measurement is completed. To.
　ステップＳ２１０においてフラグがＯＮの場合（Ｓ２１０：ｙｅｓ）、ＡＳＩＣ３０は、コンデンサＣ１の容量値Ｃ１ｎの最新値である容量値Ｃ１ｉを、コンデンサＣ１の容量値Ｃ１ｎのうちの容量値Ｃ１ｉより単位時間前の直近の容量値Ｃ１ｉ－１とのから減算した値が設定値ＣＳより大きいか否かを判定する（Ｓ３００）。 When the flag is ON in step S210 (S210: yes), the ASIC 30 sets the capacitance value C1 i , which is the latest value of the capacitance value C1 n of the capacitor C1, from the capacitance value C1 i among the capacitance values C1 n of the capacitor C1. It is determined whether or not the value subtracted from the latest capacitance value C1 i-1 before the unit time is larger than the set value CS (S300).
　設定値ＣＳは、予め設定された値であり、メモリに記憶されている。設定値ＣＳは、ステップＳ２４０の設定値ＣＳと同様にして設定される。なお、第１実施形態において、ステップＳ３００における設定値ＣＳは、ステップＳ２２０，Ｓ２４０における設定値ＣＳと同一値であるが、ステップＳ２２０，Ｓ２４０における設定値ＣＳと異なる値であってもよい。 The set value CS is a preset value and is stored in the memory. The set value CS is set in the same manner as the set value CS in step S240. In the first embodiment, the set value CS in step S300 is the same as the set value CS in steps S220 and S240, but may be different from the set value CS in steps S220 and S240.
　容量値Ｃ１ｉを容量値Ｃ１ｉ－１との差から減算した値が設定値ＣＳより大きい場合（Ｓ３００：ｙｅｓ）、ＡＳＩＣ３０は、容量値Ｃ１ｉに基づく第１圧力情報Ｐ１ｉを第１接触圧力情報ＰＣＩ１としてメモリに記憶する（Ｓ３１０）。 When the value obtained by subtracting the capacity value C1 i from the difference from the capacity value C1 i-1 is larger than the set value CS (S300: yes), the ASIC 30 first contacts the first pressure information P1 i based on the capacity value C1 i . It is stored in the memory as the pressure information PCI1 (S310).
　容量値Ｃ１ｉを容量値Ｃ１ｉ－１から減算した値が設定値ＣＳより小さい場合（Ｓ３１０：ｎｏ）、ＡＳＩＣ３０は、ステップＳ３１０を実行することなく、以下で説明するステップＳ３２０を実行する。なお、第１実施形態では、容量値Ｃ１ｉを容量値Ｃ１ｉ－１から減算した値が設定値ＣＳと等しい場合も、ＡＳＩＣ３０は、ステップＳ３１０を実行することなく、ステップＳ３２０を実行する。 When the value obtained by subtracting the capacity value C1 i from the capacity value C1 i-1 is smaller than the set value CS (S310: no), the ASIC 30 executes step S320 described below without executing step S310. In the first embodiment, even when the value obtained by subtracting the capacity value C1 i from the capacity value C1 i-1 is equal to the set value CS, the ASIC 30 executes step S320 without executing step S310.
　次に、ＡＳＩＣ３０は、コンデンサＣ２の容量値Ｃ２ｎの最新値である容量値Ｃ２ｉを、コンデンサＣ２の容量値Ｃ２ｎのうちの容量値Ｃ２ｉより単位時間前の直近の容量値Ｃ２ｉ－１から減算した値が設定値ＣＳより大きいか否かを判定する（Ｓ３２０）。 Next, the ASIC 30 sets the capacitance value C2 i , which is the latest value of the capacitance value C2 n of the capacitor C2, to the latest capacitance value C2 i- unit time before the capacitance value C2 i of the capacitance values C2 n of the capacitor C2 . It is determined whether or not the value subtracted from 1 is larger than the set value CS (S320).
　設定値ＣＳは、予め設定された値であり、メモリに記憶されている。設定値ＣＳは、ステップＳ２２０の設定値ＣＳと同様にして設定される。なお、第１実施形態において、ステップＳ３２０における設定値ＣＳは、ステップＳ２２０，Ｓ２４０，Ｓ３００における設定値ＣＳと同一値であるが、ステップＳ２２０，Ｓ２４０，Ｓ３００における設定値ＣＳと異なる値であってもよい。 The set value CS is a preset value and is stored in the memory. The set value CS is set in the same manner as the set value CS in step S220. In the first embodiment, the set value CS in step S320 has the same value as the set value CS in steps S220, S240, and S300, but even if the value is different from the set value CS in steps S220, S240, and S300. good.
　容量値Ｃ２ｉを容量値Ｃ２ｉ－１から減算した値が設定値ＣＳより小さい場合（Ｓ３２０：ｎｏ）、ＡＳＩＣ３０は、フラグ切替判定処理を終えて、測定処理のステップＳ８０以降の処理を実行する（図６参照）。 When the value obtained by subtracting the capacity value C2 i from the capacity value C2 i-1 is smaller than the set value CS (S320: no), the ASIC 30 finishes the flag switching determination process and executes the process after step S80 of the measurement process. (See FIG. 6).
　容量値Ｃ２ｉを容量値Ｃ２ｉ－１から減算した値が設定値ＣＳより大きい場合（Ｓ３２０：ｙｅｓ）、ＡＳＩＣ３０は、容量値Ｃ２ｉに基づく第２圧力情報Ｐ２ｉを第２接触圧力情報ＰＣＩ２としてメモリに記憶する（Ｓ３３０）。なお、第１実施形態では、容量値Ｃ２ｉを容量値Ｃ２ｉ－１から減算した値が設定値ＣＳと等しい場合も、ＡＳＩＣ３０はステップＳ３３０を実行する。 When the value obtained by subtracting the capacity value C2 i from the capacity value C2 i-1 is larger than the set value CS (S320: yes), the ASIC 30 uses the second pressure information P2 i based on the capacity value C2 i as the second contact pressure information PCI2. It is stored in the memory as (S330). In the first embodiment, the ASIC 30 executes step S330 even when the value obtained by subtracting the capacity value C2 i from the capacity value C2 i-1 is equal to the set value CS.
　次に、ＡＳＩＣ３０は、第１接触圧力情報ＰＣＩ１が既に決定されているか否か判定する（Ｓ３４０）。 Next, the ASIC 30 determines whether or not the first contact pressure information PCI1 has already been determined (S340).
　第１接触圧力情報ＰＣＩ１が決定されている場合（Ｓ３４０：ｙｅｓ）、つまり第１接触圧力情報ＰＣＩ１及び第２接触圧力情報ＰＣＩ２の双方が決定されている場合、ＡＳＩＣ３０は、第２接触圧力情報ＰＣＩ２が減算圧力情報より小さいか否かを判定する（Ｓ３５０）。減算圧力情報は、第１接触圧力情報ＰＣＩ１から第２設定圧力情報ＰＳ２を減算した情報である。つまり、減算圧力情報は、ＰＣＩ１－ＰＳ２である。 When the first contact pressure information PCI1 is determined (S340: yes), that is, when both the first contact pressure information PCI1 and the second contact pressure information PCI2 are determined, the ASIC 30 determines the second contact pressure information PCI2. Is smaller than the subtraction pressure information (S350). The subtracted pressure information is information obtained by subtracting the second set pressure information PS2 from the first contact pressure information PCI1. That is, the subtraction pressure information is PCI1-PS2.
　第２設定圧力情報ＰＳ２は、第１ダイアフラム２３Ｂが誘電体膜２８の上面２８Ａから離れてから、第２ダイアフラム２３Ｃが誘電体膜２６の上面２６Ａから離れるまでに、第２ダイアフラム２３Ｃに対して減らすことが必要な圧力、つまり第１接触圧力ＰＣ１と第２接触圧力ＰＣ２との圧力差に基づいて設定される情報である。第２設定圧力情報ＰＳ２は、第１ダイアフラム２３Ｂと誘電体膜２８の上面２８Ａとの間隔と、第２ダイアフラム２３Ｃと誘電体膜２６の上面２６Ａとの間隔との差や、第２ダイアフラム２３Ｃの厚み等に基づいて設定される。第１実施形態において、第２設定圧力情報ＰＳ２は、第１設定圧力情報ＰＳ１と同値に設定されている。 The second set pressure information PS2 is reduced with respect to the second diaphragm 23C from the time the first diaphragm 23B is separated from the upper surface 28A of the dielectric film 28 until the second diaphragm 23C is separated from the upper surface 26A of the dielectric film 26. This is information set based on the required pressure, that is, the pressure difference between the first contact pressure PC1 and the second contact pressure PC2. The second set pressure information PS2 is the difference between the distance between the first diaphragm 23B and the upper surface 28A of the dielectric film 28 and the distance between the second diaphragm 23C and the upper surface 26A of the dielectric film 26, and the second diaphragm 23C. It is set based on the thickness and the like. In the first embodiment, the second set pressure information PS2 is set to the same value as the first set pressure information PS1.
　第２接触圧力情報ＰＣＩ２が減算圧力情報（ＰＣＩ１－ＰＳ２）より小さい場合（Ｓ３５０：ｙｅｓ）、ＡＳＩＣ３０は、フラグをＯＦＦに設定する（Ｓ３６０）。なお、第１実施形態では、第２接触圧力情報ＰＣＩ２が減算圧力情報（ＰＣＩ１－ＰＳ２）と同値である場合も、ＡＳＩＣ３０は、フラグをＯＦＦに設定する（Ｓ３６０）。 When the second contact pressure information PCI2 is smaller than the subtraction pressure information (PCI1-PS2) (S350: yes), the ASIC30 sets the flag to OFF (S360). In the first embodiment, the ASIC 30 sets the flag to OFF even when the second contact pressure information PCI2 has the same value as the subtraction pressure information (PCI1-PS2) (S360).
　ステップＳ３４０において、第１接触圧力情報ＰＣＩ１が決定されていない場合（Ｓ３４０：ｎｏ）、直前のステップＳ３３０において第２接触圧力情報ＰＣＩ２が決定されている一方で、第１接触圧力情報ＰＣＩ１が決定されていない。この場合、ＡＳＩＣ３０は異常を示す情報を外部へ出力し（Ｓ２９０）、圧力の測定が終了される。 When the first contact pressure information PCI1 is not determined in step S340 (S340: no), the second contact pressure information PCI2 is determined in the immediately preceding step S330, while the first contact pressure information PCI1 is determined. Not. In this case, the ASIC 30 outputs information indicating an abnormality to the outside (S290), and the pressure measurement is completed.
　また、ステップＳ３５０において、第２接触圧力情報ＰＣＩ２が減算圧力情報（ＰＣＩ１－ＰＳ２）より大きい場合（Ｓ３５０：ｎｏ）、ＡＳＩＣ３０は異常を示す情報を外部へ出力して（Ｓ２９０）、圧力の測定が終了される。 Further, in step S350, when the second contact pressure information PCI2 is larger than the subtraction pressure information (PCI1-PS2) (S350: no), the ASIC30 outputs information indicating an abnormality to the outside (S290), and the pressure is measured. It will be terminated.
　以下に、図６及び図７が参照されつつ、第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する圧力が大気圧以下の値から高くなる場合における圧力測定処理が説明される。 Below, with reference to FIGS. 6 and 7, the pressure measurement process in the case where the pressure acting on the first diaphragm 23B and the second diaphragm 23C increases from the value below the atmospheric pressure will be described.
　圧力測定が開始されると、ＡＳＩＣ３０は、モニタリング（Ｓ１０）したコンデンサＣ１の容量値Ｃ１ｎ及びコンデンサＣ２の容量値Ｃ２ｎの少なくとも一方に基づいて、第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する圧力が大気圧以下であると判定する（Ｓ２０：ｎｏ）。ＡＳＩＣ３０は、フラグをＯＦＦに設定する（Ｓ４０）。 When the pressure measurement is started, the ASIC 30 acts on the first diaphragm 23B and the second diaphragm 23C based on at least one of the capacitance value C1 n of the capacitor C1 and the capacitance value C2 n of the capacitor C2 monitored (S10). It is determined that the pressure is equal to or lower than the atmospheric pressure (S20: no). The ASIC 30 sets the flag to OFF (S40).
　その後、ＡＳＩＣ３０は、コンデンサＣ１の容量値Ｃ１ｉ及びコンデンサＣ２の容量値Ｃ２ｉのモニタリング（Ｓ５０）と、フラグがＯＦＦ（Ｓ８０：ｎｏ）であることによる第１圧力情報Ｐ１ｉの出力（Ｓ１００）とを繰り返す。この時点において、第１接触圧力情報ＰＣＩ１は決定されていない。つまり、ＡＳＩＣ３０は、第１接触圧力情報ＰＣＩ１が決定されていないことを条件として、第１圧力情報Ｐ１ｎを出力する。 After that, the ASIC 30 monitors the capacitance value C1 i of the capacitor C1 and the capacitance value C2 i of the capacitor C2 (S50), and outputs the first pressure information P1 i (S100) because the flag is OFF (S80: no). And repeat. At this point, the first contact pressure information PCI1 has not been determined. That is, the ASIC 30 outputs the first pressure information P1 n on condition that the first contact pressure information PCI1 has not been determined.
　第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する圧力が高くなって第２接触圧力ＰＣ２（図５参照）となると、フラグ切替判定処理（Ｓ７０）において、容量値Ｃ２ｉから容量値Ｃ２ｉ－１を減算した値が設定値ＣＳより大きくなる（Ｓ２２０：ｙｅｓ）。これにより、ＡＳＩＣ３０は、容量値Ｃ２ｉに基づく第２圧力情報Ｐ２ｉを第２接触圧力情報ＰＣＩ２としてメモリに記憶する（Ｓ２３０）。 When the pressure acting on the first diaphragm 23B and the second diaphragm 23C becomes high and becomes the second contact pressure PC2 (see FIG. 5), in the flag switching determination process (S70), the capacitance value C2 i to the capacitance value C2 i-1 The value obtained by subtracting is larger than the set value CS (S220: yes). As a result, the ASIC 30 stores the second pressure information P2 i based on the capacitance value C2 i in the memory as the second contact pressure information PCI 2 (S230).
　第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する圧力が更に高くなって第１接触圧力ＰＣ１（図５参照）となると、フラグ切替判定処理（Ｓ７０）において、容量値Ｃ１ｉから容量値Ｃ１ｉ－１を減算した値が設定値ＣＳより大きくなる（Ｓ２４０：ｙｅｓ）。これにより、ＡＳＩＣ３０は、容量値Ｃ１ｉに基づく第１圧力情報Ｐ１ｉを第１接触圧力情報ＰＣＩ１としてメモリに記憶する（Ｓ２５０）。 When the pressure acting on the first diaphragm 23B and the second diaphragm 23C becomes higher and becomes the first contact pressure PC1 (see FIG. 5), in the flag switching determination process (S70), the capacitance value C1 i to the capacitance value C1 i-. The value obtained by subtracting 1 becomes larger than the set value CS (S240: yes). As a result, the ASIC 30 stores the first pressure information P1 i based on the capacitance value C1 i in the memory as the first contact pressure information PCI 1 (S250).
　第１接触圧力情報ＰＣＩ１及び第２接触圧力情報ＰＣＩ２の双方が決定されると（Ｓ２６０：ｙｅｓ）、ＡＳＩＣ３０は、第１接触圧力情報ＰＣＩ１が加算圧力情報（ＰＣＩ２＋ＰＳ１）より大きいか否かを判定する（Ｓ２７０）。本例では、第１接触圧力情報ＰＣＩ１が加算圧力情報（ＰＣＩ２＋ＰＳ１）より大きい（Ｓ２７０：ｙｅｓ）。そのため、ＡＳＩＣ３０は、フラグをＯＦＦからＯＮに切り替える（Ｓ２８０）。なお、異常の場合の処理は、上述した通りである。 When both the first contact pressure information PCI1 and the second contact pressure information PCI2 are determined (S260: yes), the ASIC 30 determines whether the first contact pressure information PCI1 is larger than the additional pressure information (PCI2 + PS1). (S270). In this example, the first contact pressure information PCI1 is larger than the additive pressure information (PCI2 + PS1) (S270: yes). Therefore, the ASIC 30 switches the flag from OFF to ON (S280). The processing in the case of an abnormality is as described above.
　以後、ＡＳＩＣ３０は、コンデンサＣ１の容量値Ｃ１ｉ及びコンデンサＣ２の容量値Ｃ２ｉのモニタリング（Ｓ５０）と、フラグがＯＮ（Ｓ８０：ｙｅｓ）であることによる第２圧力情報Ｐ２ｉの出力（Ｓ９０）とを繰り返す。 After that, the ASIC 30 monitors the capacitance value C1 i of the capacitor C1 and the capacitance value C2 i of the capacitor C2 (S50), and outputs the second pressure information P2 i (S90) because the flag is ON (S80: yes). And repeat.
　以下に、図６及び図７が参照されつつ、第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する圧力が大気圧より高い値から低くなる場合における圧力測定処理が説明される。 Below, with reference to FIGS. 6 and 7, the pressure measurement process in the case where the pressure acting on the first diaphragm 23B and the second diaphragm 23C becomes lower than the atmospheric pressure is described.
　圧力測定が開始されると、ＡＳＩＣ３０は、モニタリング（Ｓ１０）したコンデンサＣ１の容量値Ｃ１ｎ及びコンデンサＣ２の容量値Ｃ２ｎの少なくとも一方に基づいて、第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する圧力が大気圧より高いと判定する（Ｓ２０：ｙｅｓ）。ＡＳＩＣ３０は、フラグをＯＮに設定する（Ｓ３０）。 When the pressure measurement is started, the ASIC 30 acts on the first diaphragm 23B and the second diaphragm 23C based on at least one of the capacitance value C1 n of the capacitor C1 and the capacitance value C2 n of the capacitor C2 monitored (S10). It is determined that the pressure is higher than the atmospheric pressure (S20: yes). The ASIC 30 sets the flag to ON (S30).
　その後、ＡＳＩＣ３０は、コンデンサＣ１の容量値Ｃ１ｉ及びコンデンサＣ２の容量値Ｃ２ｉのモニタリングと（Ｓ５０）、フラグがＯＮ（Ｓ８０：ｙｅｓ）であることによる第２圧力情報Ｐ２ｉの出力とを繰り返す。この時点において、第２接触圧力情報ＰＣＩ２は決定されていない。つまり、ＡＳＩＣ３０は、第２接触圧力情報ＰＣＩ２が決定されていないことを条件として、第２圧力情報Ｐ２ｎを出力する。 After that, the ASIC 30 repeats the monitoring of the capacitance value C1 i of the capacitor C1 and the capacitance value C2 i of the capacitor C2 (S50), and the output of the second pressure information P2 i due to the flag being ON (S80: yes). .. At this point, the second contact pressure information PCI2 has not been determined. That is, the ASIC 30 outputs the second pressure information P2 n on condition that the second contact pressure information PCI 2 has not been determined.
　第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する圧力が低くなって第１接触圧力ＰＣ１（図５参照）となると、フラグ切替判定処理（Ｓ７０）において、容量値Ｃ１ｉを容量値Ｃ１ｉ－１から減算した値が設定値ＣＳより大きくなる（Ｓ３００：ｙｅｓ）。これにより、ＡＳＩＣ３０は、容量値Ｃ１ｉに基づく第１圧力情報Ｐ１ｉを第１接触圧力情報ＰＣＩ１としてメモリに記憶する（Ｓ３１０）。 When the pressure acting on the first diaphragm 23B and the second diaphragm 23C becomes low and becomes the first contact pressure PC1 (see FIG. 5), the capacitance value C1 i is changed to the capacitance value C1 i-1 in the flag switching determination process (S70). The value subtracted from is larger than the set value CS (S300: yes). As a result, the ASIC 30 stores the first pressure information P1 i based on the capacitance value C1 i in the memory as the first contact pressure information PCI 1 (S310).
　第１ダイアフラム２３Ｂ及び第２ダイアフラム２３Ｃに作用する圧力が更に低くなって第２接触圧力ＰＣ２となると、フラグ切替判定処理（Ｓ７０）において、容量値Ｃ２ｉを容量値Ｃ２ｉ－１から減算した値が設定値ＣＳより大きくなる（Ｓ３２０：ｙｅｓ）。これにより、ＡＳＩＣ３０は、容量値Ｃ２ｉに基づく第２圧力情報Ｐ２ｉを第２接触圧力情報ＰＣＩ２としてメモリに記憶する（Ｓ３３０）。 When the pressure acting on the first diaphragm 23B and the second diaphragm 23C becomes even lower and becomes the second contact pressure PC2, the value obtained by subtracting the capacitance value C2 i from the capacitance value C2 i-1 in the flag switching determination process (S70). Is larger than the set value CS (S320: yes). As a result, the ASIC 30 stores the second pressure information P2 i based on the capacitance value C2 i in the memory as the second contact pressure information PCI 2 (S330).
　第１接触圧力情報ＰＣＩ１及び第２接触圧力情報ＰＣＩ２の双方が決定されると（Ｓ３４０：ｙｅｓ）、ＡＳＩＣ３０は、第２接触圧力情報ＰＣＩ２が減算圧力情報（ＰＣＩ１－ＰＳ２）より小さいか否かを判定する（Ｓ３５０）。本例では、第２接触圧力情報ＰＣＩ２が減算圧力情報（ＰＣＩ１－ＰＳ２）より小さい（Ｓ３５０：ｙｅｓ）。そのため、ＡＳＩＣ３０は、フラグをＯＮからＯＦＦに切り替える（Ｓ３６０）。なお、異常の場合の処理は、上述した通りである。 When both the first contact pressure information PCI1 and the second contact pressure information PCI2 are determined (S340: yes), the ASIC30 determines whether the second contact pressure information PCI2 is smaller than the subtraction pressure information (PCI1-PS2). Judgment (S350). In this example, the second contact pressure information PCI2 is smaller than the subtraction pressure information (PCI1-PS2) (S350: yes). Therefore, the ASIC 30 switches the flag from ON to OFF (S360). The processing in the case of an abnormality is as described above.
　以後、ＡＳＩＣ３０は、コンデンサＣ１の容量値Ｃ１ｉ及びコンデンサＣ２の容量値Ｃ２ｉのモニタリング（Ｓ５０）と、フラグがＯＦＦ（Ｓ８０：ｎｏ）であることによる第１圧力情報Ｐ１ｉの出力（Ｓ１００）とを繰り返す。 After that, the ASIC 30 monitors the capacitance value C1 i of the capacitor C1 and the capacitance value C2 i of the capacitor C2 (S50), and outputs the first pressure information P1 i (S100) because the flag is OFF (S80: no). And repeat.
　第１実施形態によれば、圧力センサ１は、絶縁層２２に、２つの密閉された開口部２２Ｂ，２２Ｃを備えている。また、圧力センサ１は、導電層２３に、開口部２２Ｂに面した第１ダイアフラム２３Ｂと、開口部２２Ｃに面した第２ダイアフラム２３Ｃとを備えている。 According to the first embodiment, the pressure sensor 1 includes two sealed openings 22B and 22C in the insulating layer 22. Further, the pressure sensor 1 includes a first diaphragm 23B facing the opening 22B and a second diaphragm 23C facing the opening 22C in the conductive layer 23.
　誘電体膜２６が配置された開口部２２Ｃでは、第２ダイアフラム２３Ｃが誘電体膜２６と接触した状態で、第２ダイアフラム２３Ｃと誘電体膜２６との接触面積に基づいて第２ダイアフラム２３Ｃと誘電体膜２６との間の静電容量を決定することができる。この場合、第２ダイアフラム２３Ｃはタッチモードで動作する。一方、開口部２２Ｂでは、第１ダイアフラム２３Ｂが誘電体膜２８と接触していない状態で、第１ダイアフラム２３Ｂと誘電体膜２８とのギャップに基づいて開口部２２Ｂの静電容量を決定することができる。この場合、第１ダイアフラム２３Ｂはノーマルモード（非タッチモード）で動作する。 In the opening 22C in which the dielectric film 26 is arranged, the second diaphragm 23C and the dielectric are in contact with the second diaphragm 23C based on the contact area between the second diaphragm 23C and the dielectric film 26 in a state where the second diaphragm 23C is in contact with the dielectric film 26. The capacitance between the body membrane 26 and the body membrane 26 can be determined. In this case, the second diaphragm 23C operates in the touch mode. On the other hand, in the opening 22B, the capacitance of the opening 22B is determined based on the gap between the first diaphragm 23B and the dielectric film 28 in a state where the first diaphragm 23B is not in contact with the dielectric film 28. Can be done. In this case, the first diaphragm 23B operates in the normal mode (non-touch mode).
　ここで、タッチモードでは、ノーマルモードより静電容量を多くできる。そのため、タッチモードは、高圧の検出に適している。よって、第１実施形態によれば、導電層２３の厚みを部分的に変えたり、導電層２３に突起を設けたりする等の、製造工程が煩雑化するような構成とすることなく、タッチモードで動作する第２ダイアフラム２３Ｃを高圧用のダイアフラムとし、ノーマルモードで動作する第１ダイアフラム２３Ｂを低圧用のダイアフラムとすることができる。 Here, in the touch mode, the capacitance can be increased more than in the normal mode. Therefore, the touch mode is suitable for detecting high voltage. Therefore, according to the first embodiment, the touch mode is not configured to complicate the manufacturing process, such as partially changing the thickness of the conductive layer 23 or providing protrusions on the conductive layer 23. The second diaphragm 23C operating in the above can be used as a diaphragm for high pressure, and the first diaphragm 23B operating in normal mode can be used as a diaphragm for low pressure.
　第１実施形態によれば、開口部２２Ｃにゲッター２７が配置されている。ゲッター２７は、密閉空間内の残留気体を吸着する。これにより、ゲッター２７が配置された開口部２２Ｃの圧力は、開口部２２Ｂの圧力より低圧となる。そのため、第２ダイアフラム２３Ｃが誘電体膜２６に接触する圧力（第２接触圧力ＰＣ２）を、第１ダイアフラム２３Ｂが誘電体膜２８に接触する圧力（第１接触圧力ＰＣ１）より低くすることができる。これにより、例えば、導電層２３に作用する圧力が低圧から高圧へ変化する過程において、第１ダイアフラム２３Ｂが誘電体膜２８に接触してノーマルモードで動作できなくなる前に、第２ダイアフラム２３Ｃが誘電体膜２６に接触してタッチモードで動作可能となる。その結果、当該過程において、圧力センサ１が出力するダイアフラムを、低圧用の第１ダイアフラム２３Ｂから高圧用の第２ダイアフラム２３Ｃへ切り替えることを円滑に実行することができる。 According to the first embodiment, the getter 27 is arranged in the opening 22C. The getter 27 adsorbs the residual gas in the closed space. As a result, the pressure of the opening 22C in which the getter 27 is arranged becomes lower than the pressure of the opening 22B. Therefore, the pressure at which the second diaphragm 23C contacts the dielectric film 26 (second contact pressure PC2) can be made lower than the pressure at which the first diaphragm 23B contacts the dielectric film 28 (first contact pressure PC1). .. As a result, for example, in the process of changing the pressure acting on the conductive layer 23 from low pressure to high pressure, the second diaphragm 23C is dielectric before the first diaphragm 23B comes into contact with the dielectric film 28 and cannot operate in the normal mode. It comes into contact with the body membrane 26 and can operate in the touch mode. As a result, in the process, it is possible to smoothly switch the diaphragm output by the pressure sensor 1 from the first diaphragm 23B for low pressure to the second diaphragm 23C for high pressure.
　第２ダイアフラム２３Ｃが撓む際、第２ダイアフラム２３Ｃの平面視における中央部は、第２ダイアフラム２３Ｃの平面視における外縁部より大きく撓む。第１実施形態によれば、平面視におけるゲッター２７と開口部２２Ｃの中心部との距離は、平面視における誘電体膜２６と開口部２２Ｃの中心部との距離より長い。そのため、撓んだ第２ダイアフラム２３Ｃが誘電体膜２６に接触するより前にゲッター２７に接触する可能性を低くすることができる。 When the second diaphragm 23C bends, the central portion of the second diaphragm 23C in a plan view bends more than the outer edge portion of the second diaphragm 23C in a plan view. According to the first embodiment, the distance between the getter 27 and the central portion of the opening 22C in the plan view is longer than the distance between the dielectric film 26 and the central portion of the opening 22C in the plan view. Therefore, it is possible to reduce the possibility that the bent second diaphragm 23C comes into contact with the getter 27 before it comes into contact with the dielectric film 26.
　第１実施形態によれば、ゲッター２７及び誘電体膜２６はいずれも基台２１に支持されており、且つゲッター２７の厚みは誘電体膜２６の厚みより薄い。そのため、撓んだ第２ダイアフラム２３Ｃが誘電体膜２６に接触するより前にゲッター２７に接触する可能性を低くすることができる。 According to the first embodiment, both the getter 27 and the dielectric film 26 are supported by the base 21, and the thickness of the getter 27 is thinner than the thickness of the dielectric film 26. Therefore, it is possible to reduce the possibility that the bent second diaphragm 23C comes into contact with the getter 27 before it comes into contact with the dielectric film 26.
　第１実施形態によれば、ＡＳＩＣ３０は、第１接触圧力情報ＰＣＩ１を決定することによって、第１ダイアフラム２３Ｂが誘電体膜２８に接触したことを判定できる。また、ＡＳＩＣ３０は、第２接触圧力情報ＰＣＩ２を決定することによって、第２ダイアフラム２３Ｃが誘電体膜２６に接触したことを判定できる。 According to the first embodiment, the ASIC 30 can determine that the first diaphragm 23B has come into contact with the dielectric film 28 by determining the first contact pressure information PCI1. Further, the ASIC 30 can determine that the second diaphragm 23C has come into contact with the dielectric film 26 by determining the second contact pressure information PCI2.
　第１実施形態によれば、圧力センサ１に作用する圧力が大気圧以下の値から高くなる場合に、ＡＳＩＣ３０は、第１接触圧力情報ＰＣＩ１が決定されていないことを条件として第１圧力情報Ｐ１ｎを出力する。つまり、第１ダイアフラム２３Ｂが誘電体膜２８と接触していない状態において、ＡＳＩＣ３０は、第１ダイアフラム２３Ｂの撓み量に応じた第１圧力情報Ｐ１ｎを、圧力センサ１に作用する圧力に関する情報として出力できる。 According to the first embodiment, when the pressure acting on the pressure sensor 1 increases from a value below the atmospheric pressure, the ASIC 30 uses the first pressure information P1 on the condition that the first contact pressure information PCI1 has not been determined. Output n . That is, in a state where the first diaphragm 23B is not in contact with the dielectric film 28, the ASIC 30 uses the first pressure information P1 n according to the amount of deflection of the first diaphragm 23B as information regarding the pressure acting on the pressure sensor 1. Can be output.
　第１実施形態によれば、圧力センサ１に作用する圧力が大気圧以下の値から高くなる場合に、ＡＳＩＣ３０は、第１接触圧力情報ＰＣＩ１及び第２接触圧力情報ＰＣＩ２がいずれも決定され、且つ第１接触圧力情報ＰＣＩ１が加算圧力情報（ＰＣＩ２＋ＰＳ１）より大きいことを条件として第２圧力情報Ｐ２ｎを出力する。ここで、ゲッター２７が配置された開口部２２Ｃの圧力は開口部２２Ｂの圧力より低圧であるため、第２接触圧力情報ＰＣＩ２は第１接触圧力情報ＰＣＩ１より低圧に対応した情報となる。そのため、第１接触圧力情報ＰＣＩ１に対応する圧力が圧力センサ１に作用して第１ダイアフラム２３Ｂが誘電体膜２８に接触したとき、第２ダイアフラム２３Ｃは既に誘電体膜２６に接触しており、第２ダイアフラム２３Ｃはタッチモードで正常に動作している。つまり、第１ダイアフラム２３Ｂが誘電体膜２８に接触したとき、コンデンサＣ２の容量値の第２ダイアフラム２３Ｃに作用する圧力に対する関係は、概ね線形となっている。そのため、上記の条件を満たしたときに、圧力センサ１に作用する圧力としてＡＳＩＣ３０が出力する圧力情報が、第１圧力情報Ｐ１ｎから第２圧力情報Ｐ２ｎに切り替えられた場合であっても、ＡＳＩＣ３０が出力する圧力情報の精度を良好に保つことができる。 According to the first embodiment, when the pressure acting on the pressure sensor 1 increases from a value below the atmospheric pressure, the ASIC 30 determines both the first contact pressure information PCI1 and the second contact pressure information PCI2, and The second pressure information P2 n is output on condition that the first contact pressure information PCI1 is larger than the added pressure information (PCI2 + PS1). Here, since the pressure of the opening 22C in which the getter 27 is arranged is lower than the pressure of the opening 22B, the second contact pressure information PCI2 is information corresponding to a lower pressure than the first contact pressure information PCI1. Therefore, when the pressure corresponding to the first contact pressure information PCI1 acts on the pressure sensor 1 and the first diaphragm 23B comes into contact with the dielectric film 28, the second diaphragm 23C is already in contact with the dielectric film 26. The second diaphragm 23C is operating normally in the touch mode. That is, when the first diaphragm 23B comes into contact with the dielectric film 28, the relationship between the capacitance value of the capacitor C2 and the pressure acting on the second diaphragm 23C is generally linear. Therefore, even when the pressure information output by the ASIC 30 as the pressure acting on the pressure sensor 1 when the above conditions are satisfied is switched from the first pressure information P1 n to the second pressure information P2 n . The accuracy of the pressure information output by the ASIC 30 can be kept good.
　第１実施形態によれば、圧力センサ１に作用する圧力が大気圧より高い値から低くなる場合に、ＡＳＩＣ３０は、第２接触圧力情報ＰＣＩ２が決定されていないことを条件として第２圧力情報Ｐ２ｎを出力する。つまり、第２ダイアフラム２３Ｃが誘電体膜２６と接触している状態において、ＡＳＩＣ３０は、第２ダイアフラム２３Ｃと誘電体膜２６との接触面積に応じた第２圧力情報Ｐ２ｎを、圧力センサ１に作用する圧力に関する情報として出力できる。 According to the first embodiment, when the pressure acting on the pressure sensor 1 becomes lower than the atmospheric pressure, the ASIC 30 uses the second pressure information P2 on condition that the second contact pressure information PCI2 has not been determined. Output n . That is, in a state where the second diaphragm 23C is in contact with the dielectric film 26, the ASIC 30 provides the pressure sensor 1 with the second pressure information P2 n according to the contact area between the second diaphragm 23C and the dielectric film 26. It can be output as information about the acting pressure.
　第１実施形態によれば、圧力センサ１に作用する圧力が大気圧より高い値から低くなる場合に、ＡＳＩＣ３０は、第１接触圧力情報ＰＣＩ１及び第２接触圧力情報ＰＣＩ２がいずれも決定され、且つ第２接触圧力情報ＰＣＩ２が減算圧力情報（ＰＣＩ１－ＰＳ２）より小さいことを条件として第１圧力情報Ｐ１ｎを出力する。ここで、ゲッター２７が配置された開口部２２Ｃの圧力は開口部２２Ｂの圧力より低圧であるため、第２接触圧力情報ＰＣＩ２は第１接触圧力情報ＰＣＩ１より低圧に対応した情報となる。そのため、第２接触圧力情報ＰＣＩ２に対応する圧力が圧力センサ１に作用して第２ダイアフラム２３Ｃが誘電体膜２６から離れたとき、第１ダイアフラム２３Ｂは既に誘電体膜２８から離れており、第１ダイアフラム２３Ｂはノーマルモードで正常に動作している。つまり、第２ダイアフラム２３Ｃが誘電体膜２６から離れたとき、コンデンサＣ１の容量値の第１ダイアフラム２３Ｂに作用する圧力に対する関係は、前述の式に従っている。そのため、上記の条件を満たしたときに、圧力センサ１に作用する圧力としてＡＳＩＣ３０が出力する圧力情報が、第２圧力情報Ｐ２ｎから第１圧力情報Ｐ１ｎに切り替えられた場合であっても、ＡＳＩＣ３０が出力する圧力情報の精度を良好に保つことができる。 According to the first embodiment, when the pressure acting on the pressure sensor 1 becomes lower than the atmospheric pressure, the ASIC 30 determines both the first contact pressure information PCI1 and the second contact pressure information PCI2, and The first pressure information P1 n is output on condition that the second contact pressure information PCI2 is smaller than the subtraction pressure information (PCI1-PS2). Here, since the pressure of the opening 22C in which the getter 27 is arranged is lower than the pressure of the opening 22B, the second contact pressure information PCI2 is information corresponding to a lower pressure than the first contact pressure information PCI1. Therefore, when the pressure corresponding to the second contact pressure information PCI2 acts on the pressure sensor 1 and the second diaphragm 23C is separated from the dielectric film 26, the first diaphragm 23B is already separated from the dielectric film 28, and the first diaphragm 23B is separated from the dielectric film 28. 1 Diaphragm 23B is operating normally in the normal mode. That is, the relationship between the capacitance value of the capacitor C1 and the pressure acting on the first diaphragm 23B when the second diaphragm 23C is separated from the dielectric film 26 follows the above equation. Therefore, even when the pressure information output by the ASIC 30 as the pressure acting on the pressure sensor 1 when the above conditions are satisfied is switched from the second pressure information P2 n to the first pressure information P1 n . The accuracy of the pressure information output by the ASIC 30 can be kept good.
　第１実施形態によれば、圧力センサ１が正常に機能していないことを外部へ知らせることができる。 According to the first embodiment, it is possible to notify the outside that the pressure sensor 1 is not functioning normally.
　第１実施形態において、ゲッター２７は、基台２１に支持されていたが、基台２１以外に支持されていてもよい。例えば、ゲッター２７は、絶縁層２２の側面２２Ｄや、第２ダイアフラム２３Ｃの下面２３Ｃａに支持されていてもよい。 In the first embodiment, the getter 27 is supported by the base 21, but may be supported by other than the base 21. For example, the getter 27 may be supported by the side surface 22D of the insulating layer 22 or the lower surface 23Ca of the second diaphragm 23C.
　圧力センサ用チップ２０が備える基台２１、絶縁層２２、導電層２３、誘電体膜２６、誘電体膜２８、及びゲッター２７の各々の厚み（高さ方向４の長さ）は、図２に示される厚みに限らない。例えば、図２では、絶縁層２２が導電層２３より厚いが、絶縁層２２及び導電層２３が同じ厚さであってもよい。 The thicknesses (lengths in the height direction 4) of the base 21, the insulating layer 22, the conductive layer 23, the dielectric film 26, the dielectric film 28, and the getter 27 included in the pressure sensor chip 20 are shown in FIG. Not limited to the thickness shown. For example, in FIG. 2, the insulating layer 22 is thicker than the conductive layer 23, but the insulating layer 22 and the conductive layer 23 may have the same thickness.
　第１実施形態において、ＡＳＩＣ３０は、容量値Ｃ１ｉに基づいて第１圧力情報Ｐ１ｉを算出し、容量値Ｃ２ｉに基づいて第２圧力情報Ｐ２ｉを算出した。しかし、第１圧力情報Ｐ１ｉ及び第２圧力情報Ｐ２ｉは、容量値Ｃ１ｉ，Ｃ２ｉ以外によって算出されてもよい。例えば、ＡＳＩＣ３０は、基台２１、第１ダイアフラム２３Ｂ、及び第２ダイアフラム２３Ｃからの電流値と、基台２１、第１ダイアフラム２３Ｂ、及び第２ダイアフラム２３Ｃに印加される電圧値とに基づいて、圧力センサ用チップ２０におけるパッド２４Ａ，２４Ｃ間の抵抗値、及び圧力センサ用チップ２０におけるパッド２４Ｂ，２４Ｃ間の抵抗値を算出してもよい。ＡＳＩＣ３０は、圧力センサ用チップ２０におけるパッド２４Ａ，２４Ｃ間の抵抗値に基づいて第１圧力情報Ｐ１ｉを算出し、圧力センサ用チップ２０における前記のパッド２４Ｂ，２４Ｃ間の抵抗値に基づいて第２圧力情報Ｐ２ｉを算出してもよい。 In the first embodiment, the ASIC 30 calculated the first pressure information P1 i based on the capacitance value C1 i , and calculated the second pressure information P2 i based on the capacitance value C2 i . However, the first pressure information P1 i and the second pressure information P2 i may be calculated by other than the capacitance values C1 i and C2 i . For example, the ASIC 30 is based on the current values from the base 21, the first diaphragm 23B, and the second diaphragm 23C, and the voltage values applied to the base 21, the first diaphragm 23B, and the second diaphragm 23C. The resistance value between the pads 24A and 24C in the pressure sensor chip 20 and the resistance value between the pads 24B and 24C in the pressure sensor chip 20 may be calculated. The ASIC 30 calculates the first pressure information P1 i based on the resistance value between the pads 24A and 24C in the pressure sensor chip 20, and the first is based on the resistance value between the pads 24B and 24C in the pressure sensor chip 20. 2 Pressure information P2 i may be calculated.
　第１実施形態では、ステップＳ２４０においてコンデンサＣ１の急激な増加の有無が判定され、ステップＳ３００においてコンデンサＣ１の急激な減少の有無が判定された。　　 In the first embodiment, the presence or absence of a sharp increase in the capacitor C1 was determined in step S240, and the presence or absence of a sharp decrease in the capacitor C1 was determined in step S300. It was
　しかし、前述したように、開口部２２Ｂに誘電体膜２８が配置されていない場合、第１ダイアフラム２３Ｂは誘電体膜２８ではなく基台２１の上面２１Ｂに接触する。そのため、第１ダイアフラム２３Ｂが基台２１の上面２１Ｂに接触すると、コンデンサＣ１の容量値は急激に減少し、第１ダイアフラム２３Ｂが基台２１の上面２１Ｂから離れると、コンデンサＣ１の容量値は急激に増加する。つまり、コンデンサＣ１の容量値の急激な増減は第１実施形態とは逆となる。この場合、第１実施形態とは逆に、ステップＳ２４０においてコンデンサＣ１の急激な減少の有無が判定され、ステップＳ３００においてコンデンサＣ１の急激な増加の有無が判定されればよい。 However, as described above, when the dielectric film 28 is not arranged in the opening 22B, the first diaphragm 23B comes into contact with the upper surface 21B of the base 21 instead of the dielectric film 28. Therefore, when the first diaphragm 23B comes into contact with the upper surface 21B of the base 21, the capacitance value of the capacitor C1 sharply decreases, and when the first diaphragm 23B separates from the upper surface 21B of the base 21, the capacitance value of the capacitor C1 sharply decreases. Will increase to. That is, the sudden increase / decrease in the capacitance value of the capacitor C1 is the opposite of that of the first embodiment. In this case, contrary to the first embodiment, it may be determined in step S240 whether or not the capacitor C1 is suddenly decreased, and whether or not the capacitor C1 is rapidly increased in step S300.
　第１実施形態において、回路で構成されたＡＳＩＣ３０が制御部に相当していた。つまり、上述した動作は回路によって、つまりハードウェアによって実現されていた。しかし、制御部は、回路等のハードウェアに限らない。例えば、制御部は、演算装置及びメモリによって構成されていてもよい。この場合、演算装置がメモリに記憶されたプログラムを実行することによって、つまりソフトウェアによって上述した動作が実現される。また、ハードウェアとソフトウェアとの組み合わせによって上述した動作が実現されていてもよい。 In the first embodiment, the ASIC 30 configured by the circuit corresponded to the control unit. That is, the above-mentioned operation was realized by a circuit, that is, by hardware. However, the control unit is not limited to hardware such as a circuit. For example, the control unit may be composed of an arithmetic unit and a memory. In this case, the arithmetic unit executes the program stored in the memory, that is, the software realizes the above-mentioned operation. Further, the above-mentioned operation may be realized by a combination of hardware and software.
　＜第２実施形態＞
　図８は、本発明の第２実施形態に係る圧力センサが備える圧力センサ用チップの縦断面図である。第２実施形態に係る圧力センサ１の圧力センサ用チップ２０Ａが第１実施形態に係る圧力センサ１の圧力センサ用チップ２０と異なる点は、ゲッター３７が基台２１の上面２１Ｂのうちの開口部２２Ｃに面した部分の全面に亘って設けられており、誘電体膜３６がゲッター３７に支持されている点である。 <Second Embodiment>
FIG. 8 is a vertical cross-sectional view of a pressure sensor chip included in the pressure sensor according to the second embodiment of the present invention. The difference between the pressure sensor chip 20A of the pressure sensor 1 according to the second embodiment and the pressure sensor chip 20 of the pressure sensor 1 according to the first embodiment is that the getter 37 has an opening in the upper surface 21B of the base 21. It is provided over the entire surface of the portion facing 22C, and the dielectric film 36 is supported by the getter 37.
　ゲッター３７は、基台２１に支持されている。ゲッター３７は、基台２１の上面２１Ｂのうちの開口部２２Ｃに面した部分の全面に亘って設けられている。その他の点において、ゲッター３７は、第１実施形態のゲッター２７と同構成である。なお、ゲッター３７は、基台２１の上面２１Ｂのうちの開口部２２Ｃに面した部分の一部のみに設けられていてもよい。 The getter 37 is supported by the base 21. The getter 37 is provided over the entire surface of the upper surface 21B of the base 21 facing the opening 22C. In other respects, the getter 37 has the same configuration as the getter 27 of the first embodiment. The getter 37 may be provided only on a part of the upper surface 21B of the base 21 facing the opening 22C.
　誘電体膜３６は、ゲッター３７の上面３７Ａに支持されている。つまり、誘電体膜３６は、ゲッター３７を介して基台２１に支持されている。誘電体膜３６の厚み（高さ方向４の長さ）は、ゲッター３７の厚みの分、第１実施形態の誘電体膜２６より薄い。その他の点において、誘電体膜３６は、第１実施形態の誘電体膜２６と同構成である。 The dielectric film 36 is supported by the upper surface 37A of the getter 37. That is, the dielectric film 36 is supported by the base 21 via the getter 37. The thickness of the dielectric film 36 (the length in the height direction 4) is thinner than that of the dielectric film 26 of the first embodiment by the thickness of the getter 37. In other respects, the dielectric film 36 has the same configuration as the dielectric film 26 of the first embodiment.
　なお、誘電体膜３６の厚みは、ゲッター３７の厚みと誘電体膜３６の厚みとの合計が絶縁層２２より薄くなる限りにおいて任意である。つまり、誘電体膜３６の上面３６Ａと、第２ダイアフラム２３Ｃの下面２３Ｃａとの間に隙間が形成されていればよい。 The thickness of the dielectric film 36 is arbitrary as long as the total of the thickness of the getter 37 and the thickness of the dielectric film 36 is thinner than the insulating layer 22. That is, it is sufficient that a gap is formed between the upper surface 36A of the dielectric film 36 and the lower surface 23Ca of the second diaphragm 23C.
　第２実施形態によれば、平面視における誘電体膜３６と異なる位置に加えて、平面視における誘電体膜３６と重複する位置にもゲッター３７が配置されている。そのため、開口部２２Ｃに配置されるゲッター３７の体積を大きくすることができる。その結果、ゲッター３７が吸着する気体量が多くなるため、開口部２２Ｃの圧力をより低くすることができる。 According to the second embodiment, in addition to the position different from the dielectric film 36 in the plan view, the getter 37 is also arranged at the position overlapping with the dielectric film 36 in the plan view. Therefore, the volume of the getter 37 arranged in the opening 22C can be increased. As a result, the amount of gas adsorbed by the getter 37 increases, so that the pressure at the opening 22C can be further reduced.
　第２実施形態によれば、ゲッター３７が基台２１のうちの開口部２２Ｃに面した部分の一部のみに設けられている構成より、開口部２２Ｃに配置されるゲッター３７の体積を大きくすることができる。その結果、ゲッター３７が吸着する気体量が多くなるため、開口部２２Ｃの圧力をより低くすることができる。 According to the second embodiment, the volume of the getter 37 arranged in the opening 22C is larger than that in the configuration in which the getter 37 is provided only in a part of the base 21 facing the opening 22C. be able to. As a result, the amount of gas adsorbed by the getter 37 increases, so that the pressure at the opening 22C can be further reduced.
　＜第３実施形態＞
　図９は、本発明の第３実施形態に係る圧力センサが備える圧力センサ用チップの縦断面図である。第３実施形態に係る圧力センサ１の圧力センサ用チップ２０Ｂが第１実施形態に係る圧力センサ１の圧力センサ用チップ２０と異なる点は、ゲッター４７が第２ダイアフラム２３Ｃの下面２３Ｃａに接合されている点である。 <Third Embodiment>
FIG. 9 is a vertical cross-sectional view of a pressure sensor chip included in the pressure sensor according to the third embodiment of the present invention. The difference between the pressure sensor chip 20B of the pressure sensor 1 according to the third embodiment and the pressure sensor chip 20 of the pressure sensor 1 according to the first embodiment is that the getter 47 is joined to the lower surface 23Ca of the second diaphragm 23C. That is the point.
　ゲッター４７は、第２ダイアフラム２３Ｃの下面２３Ｃａに接合されている点を除いて、第１実施形態のゲッター２７と同構成である。なお、図９においてゲッター４７は、第２ダイアフラム２３Ｃの下面２３Ｃａのうちの開口部２２Ｃに面した部分の全面に亘って設けられているが、下面２３Ｃａのうちの開口部２２Ｃに面した部分の一部のみに設けられていてもよい。 The getter 47 has the same configuration as the getter 27 of the first embodiment except that it is joined to the lower surface 23Ca of the second diaphragm 23C. In FIG. 9, the getter 47 is provided over the entire surface of the lower surface 23Ca of the second diaphragm 23C facing the opening 22C, but the portion of the lower surface 23Ca facing the opening 22C. It may be provided only in a part.
　なお、前記様々な実施形態のうちの任意の実施形態を適宜組み合わせることにより、それぞれの有する効果を奏するようにすることができる。 It should be noted that by appropriately combining any of the various embodiments described above, the effects of each can be achieved.
　本発明は、適宜図面を参照しながら好ましい実施の形態に関連して充分に記載されているが、この技術に熟練した人々にとっては種々の変形や修正は明白である。そのような変形や修正は、添付した請求の範囲による本発明の範囲から外れない限りにおいて、その中に含まれると理解されるべきである。 Although the present invention has been fully described in connection with preferred embodiments with reference to the drawings as appropriate, various modifications and modifications are obvious to those skilled in the art. It should be understood that such modifications and modifications are included within the scope of the invention as long as it does not deviate from the scope of the invention according to the appended claims.
　　１　圧力センサ
　２０　圧力センサ用チップ
　２１　基台
　２２　絶縁層（第１層）
２２Ｂ　開口部（第１開口部）
２２Ｃ　開口部（第２開口部）
　２３　導電層（第２層）
２３Ｂ　第１ダイアフラム
２３Ｃ　第２ダイアフラム
　２６　誘電体膜
　２７　ゲッター
　３０　ＡＳＩＣ（制御部）
Ｃ１ｎ　容量値（第１値）
Ｃ２ｎ　容量値（第２値）
　Ｄ１　距離
　Ｄ２　距離
Ｐ１ｎ　第１圧力情報
Ｐ２ｎ　第２圧力情報
ＰＣＩ１　第１接触圧力情報
ＰＣＩ２　第２接触圧力情報
ＰＳ１　第１設定圧力情報
ＰＳ２　第２設定圧力情報 1 Pressure sensor 20 Pressure sensor chip 21 Base 22 Insulation layer (1st layer)
22B opening (first opening)
22C opening (second opening)
23 Conductive layer (second layer)
23B 1st diaphragm 23C 2nd diaphragm 26 Dielectric film 27 Getter 30 ASIC (Control unit)
C1 n capacity value (first value)
C2 n capacity value (second value)
D1 distance D2 distance P1 n 1st pressure information P2 n 2nd pressure information PCI1 1st contact pressure information PCI2 2nd contact pressure information PS1 1st set pressure information PS2 2nd set pressure information

Claims (10)

  1. 　導電性を有する基台と、
    　前記基台上に設けられ、第１開口部及び第２開口部を有し、電気的に絶縁された第１層と、
    　前記第１層における前記基台と反対側に設けられ、平面視において前記第１開口部と重複する第１ダイアフラム、及び平面視において前記第２開口部と重複する第２ダイアフラムを有し、導電性を有する第２層と、
    　前記第２開口部に配置され、前記基台に支持され、前記第１層より薄い誘電体膜と、
    　前記第２開口部に配置されたゲッターと、を備え、
    　前記第１開口部及び前記第２開口部は、密閉されている圧力センサ。     With a conductive base and
    A first layer provided on the base, having a first opening and a second opening, and electrically isolated,
    It has a first diaphragm that is provided on the opposite side of the base in the first layer and overlaps with the first opening in a plan view, and a second diaphragm that overlaps with the second opening in a plan view, and is conductive. The second layer with sex and
    A dielectric film arranged in the second opening, supported by the base, and thinner than the first layer,
    With a getter arranged in the second opening,
    The first opening and the second opening are pressure sensors that are sealed.
  2. 　平面視における前記ゲッターと前記第２開口部の中心部との距離は、平面視における前記誘電体膜と前記第２開口部の中心部との距離より長い請求項１に記載の圧力センサ。 The pressure sensor according to claim 1, wherein the distance between the getter and the center of the second opening in a plan view is longer than the distance between the dielectric film and the center of the second opening in a plan view.
  3. 　前記ゲッターは、前記基台に支持され、
    　前記ゲッターの厚みは、前記誘電体膜の厚みより薄い請求項１または２のいずれか１項に記載の圧力センサ。     The getter is supported by the base and
    The pressure sensor according to any one of claims 1 or 2, wherein the thickness of the getter is thinner than the thickness of the dielectric film.
  4. 　前記ゲッターは、前記基台に支持され、
    　前記誘電体膜は、前記ゲッターを介して前記基台に支持され、
    　前記ゲッターの厚みと前記誘電体膜の厚みとの合計は、前記第１層より薄い請求項１に記載の圧力センサ。     The getter is supported by the base and
    The dielectric film is supported by the base via the getter.
    The pressure sensor according to claim 1, wherein the sum of the thickness of the getter and the thickness of the dielectric film is thinner than that of the first layer.
  5. 　前記ゲッターは、前記基台のうちの前記第２開口部に面した部分の全面に亘って設けられている請求項４に記載の圧力センサ。 The pressure sensor according to claim 4, wherein the getter is provided over the entire surface of a portion of the base facing the second opening.
  6. 　前記基台、前記第１ダイアフラム、及び前記第２ダイアフラムと電気的に接続された制御部を備え、
    　前記制御部は、
    　前記第１ダイアフラムと前記基台との間の容量値または抵抗値である第１値を連続的にモニタリングして、前記第１値に基づいて前記第１ダイアフラムに作用する圧力に関する第１圧力情報を算出し、
    　前記第２ダイアフラムと前記基台との間の容量値または抵抗値である第２値を連続的にモニタリングして、前記第２値に基づいて前記第２ダイアフラムに作用する圧力に関する第２圧力情報を算出し、
    　前記第１値の最新値と前記第１値のうちの当該最新値より単位時間前の直近値との差が予め設定された設定値より大きくなったことを条件として、そのときの前記第１圧力情報を第１接触圧力情報とし、
    　前記第２値の最新値と前記第２値のうちの当該最新値より単位時間前の直近値との差が予め設定された設定値より大きくなったことを条件として、そのときの前記第２圧力情報を第２接触圧力情報とする請求項１から５のいずれか１項に記載の圧力センサ。     A control unit electrically connected to the base, the first diaphragm, and the second diaphragm is provided.
    The control unit
    The first value, which is the capacitance value or resistance value between the first diaphragm and the base, is continuously monitored, and the first pressure information regarding the pressure acting on the first diaphragm based on the first value. Is calculated,
    The second value, which is the capacitance value or resistance value between the second diaphragm and the base, is continuously monitored, and the second pressure information regarding the pressure acting on the second diaphragm based on the second value. Is calculated,
    The first value at that time is provided on condition that the difference between the latest value of the first value and the latest value of the first value one unit time before the latest value is larger than the preset set value. The pressure information is used as the first contact pressure information.
    The second value at that time is provided on condition that the difference between the latest value of the second value and the latest value of the second value one unit time before the latest value becomes larger than the preset set value. The pressure sensor according to any one of claims 1 to 5, wherein the pressure information is used as the second contact pressure information.
  7. 　前記制御部によって算出される前記第１圧力情報及び前記第２圧力情報が大気圧に対応する値以下から大きくなる場合において、
    　前記制御部は、
    　前記第１接触圧力情報が決定されていないことを条件として、前記第１圧力情報を出力し、
    　前記第１接触圧力情報及び前記第２接触圧力情報がいずれも決定され、且つ前記第２接触圧力情報に予め設定された第１設定圧力情報を加算した加算圧力情報より前記第１接触圧力情報が大きいことを条件として、前記第２圧力情報を出力する請求項６に記載の圧力センサ。     When the first pressure information and the second pressure information calculated by the control unit increase from a value corresponding to atmospheric pressure or less.
    The control unit
    The first pressure information is output on condition that the first contact pressure information has not been determined.
    The first contact pressure information is obtained from the added pressure information obtained by determining both the first contact pressure information and the second contact pressure information and adding the preset first set pressure information to the second contact pressure information. The pressure sensor according to claim 6, which outputs the second pressure information on condition that the pressure is large.
  8. 　前記制御部は、前記第１接触圧力情報が前記加算圧力情報より小さいこと、または前記第１接触圧力情報が決定されたときに前記第２接触圧力情報が決定されていないことを条件として、異常を示す情報を出力する請求項７に記載の圧力センサ。 The control unit is abnormal on the condition that the first contact pressure information is smaller than the added pressure information, or the second contact pressure information is not determined when the first contact pressure information is determined. The pressure sensor according to claim 7, which outputs information indicating the above.
  9. 　前記制御部によって算出される前記第１圧力情報及び前記第２圧力情報が大気圧に対応する値より大きい値から小さくなる場合において、
    　前記制御部は、
    　前記第２接触圧力情報が決定されていないことを条件として、前記第２圧力情報を出力し、
    　前記第１接触圧力情報及び前記第２接触圧力情報がいずれも決定され、且つ前記第１接触圧力情報から予め設定された第２設定圧力情報を減算した減算圧力情報より前記第２接触圧力情報が小さいことを条件として、前記第１圧力情報を出力する請求項６から８のいずれか１項に記載の圧力センサ。     When the first pressure information and the second pressure information calculated by the control unit are smaller than the value corresponding to the atmospheric pressure, the value is smaller than the value corresponding to the atmospheric pressure.
    The control unit
    The second pressure information is output on condition that the second contact pressure information has not been determined.
    Both the first contact pressure information and the second contact pressure information are determined, and the second contact pressure information is obtained from the subtraction pressure information obtained by subtracting the preset second set pressure information from the first contact pressure information. The pressure sensor according to any one of claims 6 to 8, which outputs the first pressure information on condition that the pressure is small.
  10. 　前記制御部は、前記第２接触圧力情報が前記減算圧力情報より大きいこと、または前記第２接触圧力情報が決定されたときに前記第１接触圧力情報が決定されていないことを条件として、異常を示す情報を出力する請求項９に記載の圧力センサ。 The control unit is abnormal on the condition that the second contact pressure information is larger than the subtraction pressure information, or the first contact pressure information is not determined when the second contact pressure information is determined. The pressure sensor according to claim 9, which outputs information indicating the above.
PCT/JP2021/033353 2020-11-27 2021-09-10 Pressure sensor WO2022113475A1 (en)

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Publication number Priority date Publication date Assignee Title
JP2001523814A (en) * 1997-11-13 2001-11-27 インフィネオン テクノロジース アクチエンゲゼルシャフト Micromechanical differential pressure sensor device
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