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WO2024116230A1 - Capteur de débit - Google Patents

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Publication number
WO2024116230A1
WO2024116230A1 PCT/JP2022/043732 JP2022043732W WO2024116230A1 WO 2024116230 A1 WO2024116230 A1 WO 2024116230A1 JP 2022043732 W JP2022043732 W JP 2022043732W WO 2024116230 A1 WO2024116230 A1 WO 2024116230A1
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WO
WIPO (PCT)
Prior art keywords
film structure
thin film
temperature measuring
flow
pair
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2022/043732
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English (en)
Japanese (ja)
Inventor
和宏 太田
保夫 小野瀬
憲 石橋
孝之 余語
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Astemo Ltd
Original Assignee
Hitachi Astemo Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Astemo Ltd filed Critical Hitachi Astemo Ltd
Priority to PCT/JP2022/043732 priority Critical patent/WO2024116230A1/fr
Priority to JP2024560978A priority patent/JP7765655B2/ja
Publication of WO2024116230A1 publication Critical patent/WO2024116230A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
    • G01F1/684—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
    • G01F1/688—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow using a particular type of heating, cooling or sensing element
    • G01F1/69—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow using a particular type of heating, cooling or sensing element of resistive type
    • G01F1/692—Thin-film arrangements

Definitions

  • This disclosure relates to a flow sensor.
  • the flow measurement element which is an example of a flow sensor described in Patent Document 1
  • the flow measurement element has an electrically insulating layer formed on a single crystal silicon substrate, on which a heater, upstream and downstream temperature sensors, etc. are formed, and on which a protective layer is further formed.
  • the thermal flow rate sensor described in Patent Document 2 below has a pair of heater elements mounted on the front and back of the substrate at the tip of a long and thin support part attached to a substrate such as a printed circuit board, and a temperature measuring element mounted adjacent to the heater elements, forming a flow rate detection unit (paragraphs 0069-0072, Figure 1).
  • the thermal flow velocity/flow rate sensor of Patent Document 2 has the following configuration as Example 7.
  • a temperature measuring element, a heat dissipation pattern, and a heater element are mounted on one side and the other side of the board portion, respectively. Furthermore, the heater element, the temperature measuring element, and the heat dissipation pattern are thermally connected with a member having high thermal conductivity, and the heater element and the heat dissipation pattern are thermally connected via a through hole and a circuit pattern for the heater element, improving heat transfer (paragraph 0119, Figure 8).
  • Example 7 of the thermal flow velocity/flow rate sensor in Patent Document 2 by providing a heat dissipation pattern, the difference in the amount of heat dissipated into the fluid can be reduced, and the directional characteristics can be improved so that the detection sensitivity of the flow velocity detection unit becomes omnidirectional.
  • the number of heater elements can be reduced, thereby reducing the power consumption required for heat dissipation (Patent Document 2, paragraph 0120, etc.).
  • the thermal flow velocity/flow rate sensor of Patent Document 2 has a different configuration and measurement principle from the flow rate sensor of Patent Document 1. Therefore, the heat dissipation pattern described in Patent Document 2 cannot be applied to the thin film structure of the flow rate sensor described in Patent Document 1. Even if the heat dissipation pattern of Patent Document 2 could be applied to the flow rate sensor of Patent Document 1, it would be difficult to improve the heat dissipation of the thin film structure because the heater element and the heat dissipation pattern are connected via a through hole.
  • the present disclosure provides a flow sensor that includes a heater element and a temperature measuring element and is capable of improving the heat dissipation of a thin film structure that is disposed adjacent to a cavity in a semiconductor substrate.
  • One aspect of the present disclosure is a flow sensor equipped with a flow detection unit that detects the flow rate of a gas to be measured, the flow detection unit being characterized in that it has a semiconductor substrate having a cavity, a thin film structure provided adjacent to the cavity of the semiconductor substrate, a heater element and a pair of temperature measuring elements provided in the thin film structure, and a metallic heat dissipation pattern provided in the thin film structure and electrically insulated from the heater element and the pair of temperature measuring elements.
  • a flow sensor that can improve the heat dissipation of a thin film structure that includes a heater element and a temperature measuring element and is disposed adjacent to a cavity in a semiconductor substrate.
  • FIG. 1 is a schematic diagram of a control system illustrating an embodiment of a flow sensor according to the present disclosure.
  • FIG. 2 is a front view of a physical quantity detection device used in the control system of FIG. 1 .
  • FIG. 3 is a right side view of the physical quantity detection device of FIG. 2 .
  • FIG. 3 is a rear view of the physical quantity detection device in FIG. 2 with the cover removed.
  • FIG. 5 is a front view of a circuit board of the physical quantity detection device of FIG. 4 .
  • 6 is a cross-sectional view of the circuit board and the flow sensor taken along line VI-VI in FIG. 5 .
  • FIG. 1 is a schematic diagram of an internal combustion engine control system 1 showing an embodiment of a flow sensor according to the present disclosure.
  • the internal combustion engine control system 1 includes, for example, an internal combustion engine 10, a physical quantity detection device 100, a throttle valve 25, a throttle angle sensor 26, an idle air control valve 27, an oxygen sensor 28, and a control device 4.
  • the flow sensor 150 (see FIG. 4) of this embodiment, which will be described in detail later, constitutes a part of a physical quantity detection device 100 used, for example, in an internal combustion engine control system 1.
  • the physical quantity detection device 100 is inserted into the main passage 22 through a mounting hole provided in the passage wall of the intake body, which is the main passage 22, and is used in a state where it is fixed to the passage wall of the main passage 22.
  • the physical quantity detection device 100 detects the physical quantity of the intake air, which is the measured gas 2 that is taken in through the air cleaner 21 and flows through the main passage 22, and outputs the detected physical quantity to the control device 4.
  • the physical quantity detection device 100 protrudes in the radial direction of the main passage 22 from the passage wall of the main passage 22 toward the center line 22a of the main passage 22 that is along the main flow direction of the measured gas 2 flowing through the main passage 22.
  • the protruding direction of the physical quantity detection device 100 in the main passage 22 is, for example, a direction perpendicular to the center line 22a of the main passage 22.
  • the following figures show a three-dimensional Cartesian coordinate system consisting of an X-axis parallel to the protruding direction of the physical quantity detection device 100 in the main passage 22 shown in FIG. 1, a Y-axis parallel to the center line 22a of the main passage 22, and a Z-axis parallel to the thickness direction of the physical quantity detection device 100.
  • the measurement gas 2 flows along the center line 22a (Y-axis) of the main passage 22.
  • the throttle valve 25 is built into a throttle body 23 that is arranged upstream of the intake manifold 24 in the flow direction of the measured gas 2, for example.
  • the control device 4 changes the opening of the throttle valve 25 based on the amount of accelerator pedal operation, for example, to control the flow rate of intake air as the measured gas 2 flowing into the combustion chamber in the cylinder 11 of the internal combustion engine 10.
  • the throttle angle sensor 26 measures the opening of the throttle valve 25 and outputs it to the control device 4.
  • the idle air control valve 27 controls the amount of air that bypasses the throttle valve 25.
  • the internal combustion engine 10 includes, for example, a cylinder 11, a piston 12, a spark plug 13, a fuel injection valve 14, an intake valve 15, an exhaust valve 16, and a rotation angle sensor 17.
  • Intake air is taken in through an air cleaner 21 based on the movement of the piston 12 of the internal combustion engine 10, and flows through a main passage 22, and the flow rate is controlled by a throttle valve 25 in a throttle body 23.
  • the intake air that passes through the throttle body 23 passes through an intake manifold 24, and further passes through a fuel injection valve 14 provided in an intake port, and flows into a combustion chamber in the cylinder 11 via the intake valve 15.
  • the control device 4 controls the fuel injection valve 14 based on the physical quantity of the intake air as the measured gas 2 input from the physical quantity detection device 100 to inject fuel into the intake air.
  • the intake air that passes through the intake manifold 24 is mixed with the fuel injected from the fuel injection valve 14 and is led to the combustion chamber in the form of a mixture.
  • the control device 4 explosively combusts the mixture in the combustion chamber by spark ignition from the spark plug 13, generating mechanical energy in the internal combustion engine 10.
  • the rotation angle sensor 17 detects information related to the positions and states of the piston 12, intake valve 15, and exhaust valve 16, as well as the rotation speed of the internal combustion engine 10, and outputs the information to the control device 4.
  • Gas generated by combustion is discharged from the combustion chamber of the cylinder 11 through the exhaust valve 16 into the exhaust pipe, and is discharged from the exhaust pipe as exhaust gas 3 to the outside of the vehicle.
  • the oxygen sensor 28 is provided in the exhaust pipe, and measures the oxygen concentration of the exhaust gas 3 flowing through the exhaust pipe, and outputs the measured value to the control device 4.
  • the control device 4 controls each part of the internal combustion engine control system 1 based on the physical quantities, such as flow rate, temperature, humidity, and pressure, of the intake air as the measured gas 2 flowing through the main passage 22 detected by the physical quantity detection device 100. Specifically, when the control device 4 controls the opening of the throttle valve 25 based on the amount of accelerator pedal operation, the flow rate of the intake air as the measured gas 2 flowing through the main passage 22 changes. The control device 4 controls the supply amount of fuel injected from the fuel injection valve 14 based on the flow rate of the measured gas 2 detected by the physical quantity detection device 100, for example. This controls the mechanical energy generated by the internal combustion engine 10.
  • the physical quantities such as flow rate, temperature, humidity, and pressure
  • the control device 4 calculates the fuel injection amount and ignition timing based on the physical quantity of the intake air, which is the output of the physical quantity detection device 100, and the rotation speed of the internal combustion engine 10 measured based on the output of the rotation angle sensor 17. Based on the results of these calculations, the control device 4 controls the fuel injection amount by the fuel injection valve 14 and the ignition timing of the spark plug 13. In reality, the control device 4 also finely controls the fuel supply amount and ignition timing based on the temperature of the measured gas 2, the change in the opening of the throttle valve 25, the change in the rotation speed of the internal combustion engine 10, and the air-fuel ratio of the exhaust gas 3.
  • the control device 4 further controls the amount of air bypassing the throttle valve 25 with the idle air control valve 27 when the internal combustion engine 10 is in an idle operating state, thereby controlling the rotation speed of the internal combustion engine 10 in an idle operating state.
  • the amount of fuel supplied and the ignition timing, which are the main control quantities of the internal combustion engine 10 are both calculated using the output of the physical quantity detection device 100 as a main parameter. Therefore, improving the measurement accuracy of the physical quantity detection device 100, suppressing changes over time, and improving reliability are important for improving the control accuracy of the vehicle and ensuring reliability.
  • the physical quantity detection device 100 is also attached to an intake pipe that is affected by heat generated by the internal combustion engine 10. Therefore, the heat generated by the internal combustion engine 10 is transmitted to the physical quantity detection device 100 via the intake pipe. Since the physical quantity detection device 100 detects the flow rate of the measured gas 2 by transferring heat to the measured gas 2, it is important to suppress the influence of heat from the outside as much as possible.
  • Figs. 2 to 4 are respectively a front view, a right side view, and a rear view with the cover 120 removed of the physical quantity detection device 100 used in the internal combustion engine control system 1 of Fig. 1.
  • the physical quantity detection device 100 includes, for example, a housing 110 and a cover 120.
  • the housing 110 is manufactured, for example, by injection molding a synthetic resin material.
  • the cover 120 is, for example, a plate-shaped member made of metal or synthetic resin.
  • the cover 120 can be, for example, a molded product made of synthetic resin material.
  • the housing 110 and the cover 120 form the housing of the physical quantity detection device 100 that is placed in the main passage 22.
  • the housing 110 has, for example, a flange 111, a connector 112, and a measuring unit 113.
  • the flange 111 has a generally rectangular plate-like shape in a plan view of the physical quantity detection device 100 in the protruding direction (X-axis direction), and has a pair of fixing parts 111a at diagonal corners.
  • the fixing part 111a has a cylindrical through hole in the center that passes through the flange 111 and allows a fixing screw to be inserted.
  • the measurement part 113 is inserted into an attachment hole provided in the main passage 22.
  • the fixing screw inserted into the through hole of the flange 111 is screwed into the threaded hole of the main passage 22 and fastened, fixing the flange 111 to the passage wall of the main passage 22.
  • the physical quantity detection device 100 is fixed to the main passage 22, which is the intake body, and the housing 110 is set in the main passage 22.
  • the connector 112 protrudes from the flange 111, is disposed outside the main passage 22, which is the intake body, and is connected to an external device. As shown in FIG. 3, a plurality of external terminals 112a and correction terminals 112b are provided inside the connector 112.
  • the external terminals 112a include, for example, output terminals for physical quantities such as flow rate and temperature, which are the measurement results of the physical quantity detection device 100, and power supply terminals for supplying DC power to operate the physical quantity detection device 100.
  • the correction terminal 112b is used to measure the physical quantity after the physical quantity detection device 100 is manufactured, to obtain a correction value for each physical quantity detection device 100, and to store the correction value in the internal memory of the physical quantity detection device 100.
  • the physical quantity detection device 100 subsequently measures the physical quantity, correction data based on the correction value stored in the memory is used, and the correction terminal 112b is not used.
  • the measuring section 113 extends from the flange 111 fixed to the passage wall of the main passage 22 toward the center line 22a of the main passage 22 so as to protrude in the radial direction of the main passage 22 perpendicular to the center line 22a.
  • the measuring section 113 has a generally rectangular parallelepiped flattened angular shape.
  • the measuring section 113 has a length in the protruding direction (X-axis direction) of the measuring section 113 in the main passage 22, and a width in the main flow direction (Y-axis direction) of the measured gas 2 in the main passage 22.
  • the measuring section 113 also has a thickness in the direction (Z-axis direction) perpendicular to the protruding direction (X-axis direction) and the main flow direction (Y-axis direction) of the measured gas 2. In this way, the measuring section 113 has a flat shape along the main flow direction of the measured gas 2, thereby reducing the fluid resistance to the measured gas 2.
  • the measurement section 113 has a front surface 113a, a back surface 113b, an upstream side surface 113c, a downstream side surface 113d, and a bottom surface 113e.
  • the front surface 113a and the back surface 113b have a larger area than the other surfaces of the measurement section 113, and are generally parallel to the protruding direction of the measurement section 113 (X-axis direction) and the center line 22a (Y-axis direction) of the main passage 22.
  • the upstream side surface 113c and the downstream side surface 113d have an elongated shape with a smaller area than the front surface 113a and the back surface 113b, and are generally perpendicular to the center line 22a (Y-axis direction) of the main passage 22.
  • the bottom surface 113e has a smaller area than the other surfaces of the measurement section 113, is generally parallel to the center line 22a (Y-axis direction) of the main passage 22, and is generally perpendicular to the protruding direction of the measurement section 113 (X-axis direction).
  • the measuring section 113 has a sub-passage inlet 114 on the upstream side surface 113c, and a first outlet 115 and a second outlet 116 on the downstream side surface 113d.
  • the sub-passage inlet 114, the first outlet 115, and the second outlet 116 are provided at the tip of the measuring section 113, which is closer to the tip than the center in the protruding direction (X-axis direction) of the measuring section 113. This allows the measured gas 2 near the center of the main passage 22, which is away from the inner wall surface of the main passage 22, to be taken in from the sub-passage inlet 114. Therefore, the physical quantity detection device 100 can suppress a decrease in measurement accuracy due to the influence of heat from the internal combustion engine 10.
  • the housing 110 has a concave bypass passage groove 117 and a concave circuit chamber 118 on the rear surface 113b side of the measuring section 113.
  • the circuit chamber 118 houses a circuit board 140.
  • the opening of the bypass passage groove 117 is closed by the cover 120 to form a bypass passage 130 together with the cover 120.
  • the bypass passage 130 takes in a portion of the measured gas 2 flowing through the main passage 22 and diverts it.
  • the portion of the measured gas 2 flowing through the main passage 22 is taken in by the bypass passage 130 from, for example, a bypass passage inlet 114 that opens into the upstream side surface 113c of the measuring section 113.
  • the bypass passage groove 117 has, for example, a first bypass passage groove 117a and a second bypass passage groove 117b.
  • the first bypass passage groove 117a extends along the center line 22a (Y-axis direction) of the main passage 22 from the bypass passage inlet 114 opening on the upstream side surface 113c of the measuring section 113 to the first outlet 115 opening on the downstream side surface 113d of the measuring section 113.
  • the first bypass passage groove 117a forms a first bypass passage 131 between itself and the cover 120.
  • the first bypass passage 131 returns the measured gas 2 taken in from the bypass passage inlet 114 to the main passage 22 from the first outlet 115.
  • the second bypass passage groove 117b branches off from the first bypass passage groove 117a midway and extends toward the flange 111 along the protruding direction (X-axis direction) of the measuring section 113. Furthermore, the second bypass passage groove 117b curves in a U-shape so as to turn back in the opposite direction and extends toward the tip of the measuring section 113 along the protruding direction (X-axis direction) of the measuring section 113.
  • the second bypass passage groove 117b curves in a direction along the center line 22a (Y-axis direction) of the main passage 22 at the tip of the measuring section 113, and is connected to a second outlet 116 that opens into the downstream side surface 113d of the measuring section 113.
  • the opening of the second bypass passage groove 117b is closed by the cover 120 to form a second bypass passage 132 between the cover 120 and the second bypass passage 130.
  • the bypass passage 130 includes a first bypass passage 131 and a second bypass passage 132.
  • the circuit chamber 118 is recessed on the rear surface 113b side of the measuring section 113 of the housing 110, on the base end side of the measuring section 113 connected to the flange 111, and houses the circuit board 140.
  • the circuit chamber 118 is disposed on the base end side of the measuring section 113 relative to the first bypass passage groove 117a of the bypass passage groove 117, adjacent to the upstream side of the second bypass passage groove 117b in the main flow direction (Y-axis direction) of the measured gas 2 flowing through the main passage 22.
  • FIG. 5 is a front view of the circuit board 140 of the physical quantity detection device 100 of FIG. 4.
  • a flow sensor 150 a temperature sensor 160, a pressure sensor 170, and a humidity sensor 180 are mounted on the circuit board 140.
  • the temperature sensor 160 is, for example, a chip-type temperature sensor mounted on the circuit board 140.
  • the temperature sensor 160 is disposed at the tip of the extension portion 140c of the circuit board 140 that extends toward the tip of the measurement portion 113 in the protruding direction (X-axis direction) of the measurement portion 113.
  • the temperature sensor 160 is disposed in the temperature measurement passage 190 of the measurement portion 113 shown in FIG. 2 and FIG. 4, and measures the temperature of the measured gas 2 taken into the temperature measurement passage 190 from the main passage 22.
  • the pressure sensor 170 is mounted on the surface of the circuit board 140 and disposed in the circuit chamber 118, for example, as shown in Figures 4 and 5.
  • the circuit chamber 118 is connected to the folded portion of the second bypass passage groove 117b, which curves in a U-shape near the flange 111, i.e., the folded portion of the second bypass passage 132. This makes it possible to measure the pressure of the measurement gas 2 taken into the bypass passage 130 by the pressure sensor 170 disposed in the circuit chamber 118.
  • the humidity sensor 180 is mounted on the surface of the circuit board 140, for example, as shown in Figures 4 and 5, and is disposed in a partitioned area closer to the tip of the measuring section 113 than the circuit chamber 118. This partitioned area is connected to, for example, the second sub-passage 132 of the sub-passage 130. In this way, the humidity sensor 180 detects the humidity of the measurement gas 2 taken into the sub-passage 130.
  • FIG. 6 is a cross-sectional view of the circuit board 140 and the flow sensor 150 taken along line VI-VI in FIG. 5.
  • the flow sensor 150 is, for example, a chip package mounted on the surface of the circuit board 140.
  • the flow sensor 150 has a first resin part 150a and a second resin part 150b.
  • the first resin part 150a and the second resin part 150b are resin sealing parts molded integrally by, for example, transfer molding of a thermosetting resin. As shown in FIG. 4, the first resin part 150a is disposed in the second bypass passage groove 117b that forms a bypass passage in the housing 110, and the second resin part 150b is disposed in the circuit chamber 118 of the housing 110.
  • the flow sensor 150 has a flow detection portion 151.
  • the flow detection portion 151 is provided in the first resin portion 150a, and detects the flow rate of the measured gas 2 flowing through the secondary passage 130.
  • the flow sensor 150 is, for example, a thermal flow sensor, and the flow detection portion 151 has a semiconductor substrate 151a having a cavity 151b, and a thin film structure 151d provided adjacent to the cavity 151b of the semiconductor substrate 151a.
  • the semiconductor substrate 151a is, for example, a single crystal silicon substrate.
  • the cavity 151b and the thin film structure 151d can be manufactured, for example, using semiconductor manufacturing technology as follows. First, a silicon dioxide layer is formed as an electrically insulating layer on the single crystal silicon substrate by thermal oxidation or chemical vapor deposition (CVD). A polycrystalline silicon layer is then formed on top of that by CVD or the like, and an impurity such as phosphorus (P) is then doped to obtain a polycrystalline silicon layer with the desired resistance value.
  • CVD chemical vapor deposition
  • the polycrystalline silicon layer on the electrical insulation layer formed on the surface of the semiconductor substrate 151a is patterned. This allows the heater element and pair of temperature measuring elements, the heater wiring and temperature measuring wiring respectively connected to these elements, the heater temperature measuring element, the reference temperature measuring element and pair of resistance elements, etc., to be formed on the electrical insulation layer.
  • the above elements and wiring may be produced, for example, by forming a metal layer of platinum (Pt) or molybdenum (Mo) or the like on an electrical insulating layer by CVD or the like and patterning it. Next, a silicon nitride layer or silicon dioxide layer is formed as a protective layer by CVD or the like on the electrical insulating layer on which the above elements and wiring are formed. After that, the protective layer is patterned and removed from the portion where the electrode pads are to be formed.
  • a metal layer of platinum (Pt) or molybdenum (Mo) or the like on an electrical insulating layer by CVD or the like and patterning it.
  • a silicon nitride layer or silicon dioxide layer is formed as a protective layer by CVD or the like on the electrical insulating layer on which the above elements and wiring are formed. After that, the protective layer is patterned and removed from the portion where the electrode pads are to be formed.
  • a metal layer is formed by CVD or the like and patterned to form electrode pads and a heat dissipation pattern, which will be described later.
  • a silicon nitride layer that serves as a mask is formed by CVD or the like on the surface of the semiconductor substrate 151a on which no electrical insulating layer or elements are formed, and then patterned. Thereafter, anisotropic etching is used to form the cavity 151b in the semiconductor substrate 151a.
  • each flow detection unit 151 is, for example, a rectangular plate with long sides of about 5 mm and short sides of about 2.5 mm.
  • FIG. 7 is a plan view of the flow detection portion 151 of the flow sensor 150 of FIG. 6.
  • FIG. 7 is a plan view of the thin film structure 151d of the semiconductor substrate 151a, viewed from the opposite side of the cavity portion 151b in the thickness direction (Z-axis direction) of the circuit board 140 shown in FIG. 6. Note that FIG. 7 omits the illustration of the protective layer that covers the elements and wiring on the electrical insulation layer 151c formed on the surface of the semiconductor substrate 151a.
  • the flow rate detection unit 151 has a semiconductor substrate 151a having a cavity 151b, and a thin film structure 151d provided adjacent to the cavity 151b of the semiconductor substrate 151a.
  • the flow rate detection unit 151 also has a heater element 151e and a pair of temperature measuring elements 151f provided in the thin film structure 151d.
  • the heater element 151e is provided, for example, in the length direction Dl of the thin film structure 151d along the flow direction (X-axis direction) of the measured gas 2, and at the center in the width direction Dw of the thin film structure 151d perpendicular to the length direction Dl.
  • the heater element 151e is connected to a pair of heater wires 151h.
  • the heater element 151e generates heat when power is supplied via the heater wires 151h, and heats the measured gas 2 flowing along the thin film structure 151d.
  • the heater element 151e generates heat, which generates a temperature distribution in the thin film structure 151d.
  • the material of the heater element 151e and the heater wires 151h is, for example, molybdenum (Mo) with a thermal conductivity of approximately 142 [W/mK].
  • the pair of temperature measuring elements 151f are arranged on both sides of the heater element 151e in the length direction Dl of the thin film structure 151d along the flow direction (X-axis direction) of the gas to be measured 2. That is, in the length direction Dl of the thin film structure 151d, the heater element 151e is arranged between the pair of temperature measuring elements 151f.
  • Each heater element 151e has, for example, two resistance wires that extend parallel to each other and repeatedly bend and meander. One end and the other end of each resistance wire of each temperature measuring element 151f are connected to temperature measuring wiring 151i, respectively.
  • the pair of temperature measuring elements 151f detects the temperature difference occurring between the upstream and downstream sides of the heater element 151e in the flow direction (X-axis direction) of the measured gas 2. This temperature difference between the upstream and downstream sides of the heater element 151e occurs when the measured gas 2 heated by the heater element 151e flows along the length direction Dl of the thin film structure 151d.
  • the material of the temperature measuring element 151f and the temperature measuring wiring 151i is, for example, a metal such as molybdenum (Mo) like the heater element 151e.
  • the flow rate detection unit 151 also has a metallic heat dissipation pattern 151g that is electrically insulated from the heater element 151e and the pair of temperature measuring elements 151f in the thin film structure 151d. More specifically, in this embodiment, two pairs of heat dissipation patterns 151g are arranged on both sides of the pair of temperature measuring elements 151f in the width direction Dw perpendicular to the length direction Dl of the thin film structure 151d.
  • These four heat dissipation patterns 151g are spaced apart from surrounding elements and wiring, including, for example, heater element 151e, temperature measurement element 151f, heater wiring 151h, and temperature measurement wiring 151i, and are electrically insulated from these surrounding elements and wiring.
  • Each heat dissipation pattern 151g may be connected to a ground wiring or ground pattern.
  • each heat dissipation pattern 151g has, for example, a triangular shape, and the dimension in the width direction Dw of the thin film structure 151d decreases as it moves away from the heater element 151e in the length direction Dl of the thin film structure 151d. Furthermore, the heat dissipation pattern 151g, the heater element 151e, and the pair of temperature measuring elements 151f are formed of the same metal material, for example, molybdenum (Mo).
  • Mo molybdenum
  • the flow rate detection unit 151 further includes, for example, a heater temperature measuring element 151j, a reference temperature measuring element 151m, and a pair of resistance elements 151n.
  • the heater temperature measuring element 151j is provided, for example, in the thin film structure 151d between the heater element 151e and the pair of temperature measuring elements 151f, and detects the temperature of the heater element 151e.
  • the heater temperature measuring element 151j includes, for example, a resistance wire that is bent so as to surround three sides of the heater element 151e, and one end and the other end of this resistance wire are each connected to the heater temperature measuring wiring 151k.
  • the reference temperature measuring element 151m is provided, for example, on the semiconductor substrate 151a near the thin film structure 151d outside the thin film structure 151d, and measures the reference temperature.
  • the reference temperature is, for example, the temperature of the semiconductor substrate 151a that is not affected by the heater element 151e outside the thin film structure 151d adjacent to the cavity 151b.
  • the reference temperature measuring element 151m is provided midway through the heater temperature measuring wire 151k that is connected to one end of the heater temperature measuring element 151j, and is connected in series to one end of the heater temperature measuring element 151j via the heater temperature measuring wire 151k.
  • the pair of resistor elements 151n are provided, for example, near a plurality of electrode pads 151p provided on one side of the semiconductor substrate 151a separated from the thin film structure 151d, and are connected in series with each other. One end of the pair of resistor elements 151n is connected to a common electrode pad 151p, and the other ends of the pair of resistor elements 151n are each connected to a different electrode pad 151p.
  • a heater temperature measuring element 151j and a reference temperature measuring element 151m connected in series are connected in parallel to a pair of resistor elements 151n connected in series to form a bridge circuit for temperature control.
  • Each electrode pad 151p connected to the pair of resistor elements 151n is connected to, for example, the power supply or ground of the bridge circuit.
  • the flow rate detection unit 151 measures the flow rate of the measurement gas 2 flowing through the measurement flow path 132a formed between the circuit board 140 and the groove 150c of the flow sensor 150, as shown in FIG. 6, for example.
  • the measurement flow path 132a is formed in the second bypass passage groove 117b of the bypass passage groove 117, i.e., in the second bypass passage 132 of the bypass passage 130, as shown in FIG. 4, for example.
  • the flow sensor 150 has, for example, an electronic component 152 and a lead frame 153.
  • the electronic component 152 is mounted on the lead frame 153 together with the flow detection unit 151.
  • the electronic component 152 is, for example, an LSI, and is connected to the flow detection unit 151 via bonding wires to drive the flow detection unit 151.
  • the flow sensor 150 detects the flow rate of the measured gas 2, for example, by detecting the temperature difference between a pair of temperature measuring elements 151f of the flow detection unit 151.
  • the flow sensor 150 of this embodiment includes a flow detection unit 151 that detects the flow rate of the measured gas 2.
  • the flow detection unit 151 includes a semiconductor substrate 151a having a cavity 151b, a thin film structure 151d provided adjacent to the cavity 151b of the semiconductor substrate 151a, and a heater element 151e and a pair of temperature measuring elements 151f provided on the thin film structure 151d.
  • the flow detection unit 151 includes a metallic heat dissipation pattern 151g provided in the thin film structure 151d and electrically insulated from the heater element 151e and the pair of temperature measuring elements 151f.
  • the flow sensor 150 of this embodiment can dissipate heat from the thin film structure 151d heated by the heater element 151e by conducting it to the metal heat dissipation pattern 151g, which has low thermal resistance.
  • the heat dissipation pattern 151g is electrically insulated from the heater element 151e and the pair of temperature measuring elements 151f, and is provided independently from the surrounding elements and wiring. This can further improve the heat dissipation properties of the thin film structure 151d.
  • the degree of freedom in the layout of the heat dissipation pattern 151g is improved, and the area of the heat dissipation pattern 151g can be increased, thereby further improving the heat dissipation of the thin film structure 151d.
  • the improved heat dissipation of the thin film structure 151d improves the responsiveness of the flow rate detection of the flow sensor 150, which detects the flow rate of the measured gas 2 based on the temperature difference between the pair of temperature measuring elements 151f. Therefore, according to the flow sensor 150 of this embodiment, it is possible to improve the detection accuracy of the flow rate when pulsation occurs in the measured gas 2.
  • a heater element 151e is arranged between a pair of temperature measuring elements 151f in the length direction Dl of the thin film structure 151d along the flow direction (X-axis direction) of the measured gas 2.
  • two pairs of heat dissipation patterns 151g are arranged on both sides of the pair of temperature measuring elements 151f in the width direction Dw perpendicular to the length direction Dl of the thin film structure 151d.
  • the flow sensor 150 of this embodiment can further improve the heat dissipation of the thin film structure 151d heated by the heater element 151e. More specifically, in the width direction Dw of the thin film structure 151d that is roughly perpendicular to the flow direction of the measured gas 2, the heat dissipation patterns 151g are arranged on both sides of each temperature measuring element 151f, and the area is enlarged compared to when they are arranged on only one side.
  • the heat generated by the heater element 151e is conducted to the heat dissipation pattern 151g, the area of which is enlarged on both sides of each temperature measuring element 151f, in the width direction Dw of the thin film structure 151d, and is then conducted to the semiconductor substrate 151a outside the thin film structure 151d and dissipated. This further improves the heat dissipation properties of the thin film structure 151d.
  • the dimension of the heat dissipation pattern 151g in the width direction Dw of the thin film structure 151d decreases as it moves away from the heater element 151e in the length direction Dl of the thin film structure 151d.
  • the flow sensor 150 of this embodiment can improve the heat dissipation performance of the heat dissipation pattern 151g in the width direction Dw of the flow detection portion 151 the closer it is to the heater element 151e in the length direction Dl of the thin film structure 151d.
  • the effect of the heat dissipation pattern 151g on a pair of temperature measuring elements 151f that are separated from the heater element 151e in the length direction Dl of the thin film structure 151d can be reduced, and a decrease in the sensitivity of the flow detection by the flow sensor 150 can be suppressed. Therefore, the responsiveness of the flow detection by the flow sensor 150 can be improved while a decrease in the sensitivity of the flow detection can be suppressed.
  • the heat dissipation pattern 151g, the heater element 151e, and the pair of temperature measuring elements 151f are made of the same metal material.
  • the flow sensor 150 of this embodiment can simultaneously manufacture the heat dissipation pattern 151g, heater element 151e, and pair of temperature measuring elements 151f of the flow detection unit 151 using the semiconductor manufacturing technology described above. This allows for a simplified structure and improved productivity of the flow detection unit 151 of the flow sensor 150.
  • the flow detection unit 151 has a bridge circuit including a heater temperature measuring element 151j, a reference temperature temperature measuring element 151m, and a pair of resistance elements 151n.
  • the heater temperature measuring element 151j is provided between the heater element 151e and the pair of temperature measuring elements 151f in the thin film structure 151d.
  • the reference temperature measuring element 151m and the pair of resistance elements 151n are provided on the semiconductor substrate 151a outside the thin film structure 151d.
  • the flow sensor 150 of this embodiment can control the temperature of the heater element 151e using a bridge circuit including the heater temperature measuring element 151j, the reference temperature measuring element 151m, and a pair of resistor elements 151n.
  • a flow sensor 150 that includes a heater element 151e and a temperature measuring element 151f and is capable of improving the heat dissipation of the flow detection unit 151 that is provided adjacent to the cavity 151b of the semiconductor substrate 151a.
  • FIG. 8 is a plan view showing a modified example of the flow detection section 151 of the flow sensor 150 shown in FIG. 7.
  • the heater element 151e and the heat dissipation pattern 151g provided on only one side of the pair of temperature measuring elements 151f in the width direction Dw of the thin film structure 151d extend to the outside of the thin film structure 151d.
  • the other configuration of the flow detection section 151 of the physical quantity detection device 100 according to this modification is similar to that of the flow detection section 151 of the flow sensor 150 according to the embodiment described above shown in FIG. 7, so similar parts are denoted by the same reference numerals and description will be omitted.
  • the heat dissipation pattern 151g extends from near the heater element 151e of the thin film structure 151d to above the semiconductor substrate 151a outside the thin film structure 151d.
  • the heat dissipation properties of the thin film structure 151d can be improved.
  • the responsiveness of the flow sensor 150 in detecting the flow rate can be improved, and the detection accuracy of the flow rate when the measured gas 2 is pulsating can be improved.

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  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Volume Flow (AREA)

Abstract

Un capteur de débit selon la présente divulgation comprend une unité de détection de débit (151) qui détecte le débit d'un gaz (2) à mesurer. L'unité de détection de débit (151) comprend : un substrat semi-conducteur (151a) qui présente une section de cavité (151b) ; une structure de film mince (151d) disposée adjacente à la section de cavité (151b) du substrat semi-conducteur (151a) ; un élément chauffant (151e) et une paire d'éléments de mesure de température (151f) qui sont disposés sur la structure de film mince (151d) ; et un motif de dissipation de chaleur métallique (151g) qui est formé dans l'unité de détection de débit (151) tout en étant électriquement isolé de l'élément chauffant (151e) et de la paire d'éléments de mesure de température (151f).
PCT/JP2022/043732 2022-11-28 2022-11-28 Capteur de débit Ceased WO2024116230A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PCT/JP2022/043732 WO2024116230A1 (fr) 2022-11-28 2022-11-28 Capteur de débit
JP2024560978A JP7765655B2 (ja) 2022-11-28 2022-11-28 流量センサ

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2022/043732 WO2024116230A1 (fr) 2022-11-28 2022-11-28 Capteur de débit

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WO2024116230A1 true WO2024116230A1 (fr) 2024-06-06

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JP (1) JP7765655B2 (fr)
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0493768A (ja) * 1990-08-09 1992-03-26 Yamatake Honeywell Co Ltd 流速センサ
JPH04158263A (ja) * 1990-10-23 1992-06-01 Yamatake Honeywell Co Ltd 流速センサ
JPH10253414A (ja) * 1997-03-05 1998-09-25 Unisia Jecs Corp 流量検出装置
JP2012073206A (ja) * 2010-09-30 2012-04-12 Hitachi Automotive Systems Ltd 熱式流量センサ

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0493768A (ja) * 1990-08-09 1992-03-26 Yamatake Honeywell Co Ltd 流速センサ
JPH04158263A (ja) * 1990-10-23 1992-06-01 Yamatake Honeywell Co Ltd 流速センサ
JPH10253414A (ja) * 1997-03-05 1998-09-25 Unisia Jecs Corp 流量検出装置
JP2012073206A (ja) * 2010-09-30 2012-04-12 Hitachi Automotive Systems Ltd 熱式流量センサ

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JPWO2024116230A1 (fr) 2024-06-06

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