WO2017086086A1 - Capteur de débit - Google Patents

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Publication number
WO2017086086A1
WO2017086086A1 PCT/JP2016/081126 JP2016081126W WO2017086086A1 WO 2017086086 A1 WO2017086086 A1 WO 2017086086A1 JP 2016081126 W JP2016081126 W JP 2016081126W WO 2017086086 A1 WO2017086086 A1 WO 2017086086A1
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WO
WIPO (PCT)
Prior art keywords
heating resistor
resistor
resistance
temperature detector
flow sensor
Prior art date
Application number
PCT/JP2016/081126
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English (en)
Japanese (ja)
Inventor
佐久間　憲之
忍 田代
保夫 小野瀬
良介 土井
太田　和宏
Original Assignee
日立オートモティブシステムズ株式会社
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Application filed by 日立オートモティブシステムズ株式会社 filed Critical 日立オートモティブシステムズ株式会社
Publication of WO2017086086A1 publication Critical patent/WO2017086086A1/fr

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    • 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
    • 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
    • G01F1/696—Circuits therefor, e.g. constant-current flow meters
    • G01F1/698—Feedback or rebalancing circuits, e.g. self heated constant temperature flowmeters

Definitions

  • the present invention relates to a flow sensor.
  • thermal flow sensors manufactured by MEMS (Micro Electro Mechanical Systems) technology as a flow sensor installed in electronically controlled fuel injection devices for internal combustion engines such as automobiles can reduce costs and are low. It is attracting attention because it can be driven by electric power.
  • Patent Document 1 Japanese Patent Application Laid-Open No. 2012-78228 as background art in this technical field.
  • Patent Document 1 when a heating resistor and a resistance temperature detector are formed of the same material on the same substrate, if the bridge circuit is configured with the resistor, only the heating resistor is thermally deteriorated at a high temperature. A problem is described in which the balance of the advance bridge circuit changes, leading to a decrease in flow rate accuracy.
  • a countermeasure a low-temperature heating resistor is added between the heating resistor and the resistance temperature detector, and a temperature measuring resistor and a bridge circuit are formed. It is described that it can be monitored and can maintain high performance over a long period of time.
  • Patent Document 2 Japanese Patent Application Laid-Open No. 2012-78228 provides three terminals in a heating resistor, and energizes the heating resistor through these terminals, whereby an upstream heating resistor and a downstream heating element are provided.
  • Technology that generates a difference in the amount of heat generated between the resistor and the thermal effect that the upstream resistance temperature detector receives from the heating resistor, and the thermal effect that the downstream resistance resistor receives from the heating resistor Is described. This makes it possible to freely change the temperature difference-flow rate characteristic that is a reference for flow rate measurement, and to cancel the shift of the detected value due to an application error.
  • a flow sensor includes a first heating resistor and an upstream temperature measuring resistor provided on the upstream side of the first heating resistor and spaced from the first heating resistor. And a downstream temperature measuring resistor provided on the downstream side of the first heating resistor, and a second heating element provided on the upstream temperature measuring resistor via an insulator. And a resistor.
  • the second heating resistor is heated by feeding to heat the upstream resistance temperature detector, and the difference between the resistance value of the upstream resistance temperature detector and the resistance value of the downstream resistance resistor is within an allowable range. By doing so, the zero point correction of the flow sensor is performed.
  • a highly sensitive and highly accurate flow sensor can be realized.
  • FIG. 3 is a plan view of a main part of a sensor chip according to Example 1.
  • FIG. FIG. 2 is a cross-sectional view of a main part of the sensor chip taken along line AA ′ in FIG. 1. It is a principal part top view of a sensor module provided with the sensor chip of FIG.
  • FIG. 4 is a cross-sectional view of a main part of the sensor module taken along line BB ′ in FIG. 3. It is principal part sectional drawing of the intake passage of the internal combustion engine in which the thermal type fluid flow sensor by Example 1 was attached.
  • 6 is a cross-sectional view of a main part of a sensor chip according to a modification of Example 1.
  • FIG. 1 is a circuit diagram of a thermal fluid flow sensor according to Embodiment 1.
  • FIG. 1 is a circuit diagram of a thermal fluid flow sensor according to Embodiment 1.
  • FIG. 6 is a plan view of a main part of a sensor chip according to a second embodiment.
  • FIG. 11 is a cross-sectional view of main parts of the sensor chip taken along the line CC ′ of FIG. 10.
  • 6 is a cross-sectional view of a main part of a sensor chip according to Example 3.
  • FIG. 10 is a plan view of a main part of a sensor chip according to Example 4.
  • FIG. 10 It is principal part sectional drawing of the sensor chip in the DD 'line of FIG. 10 is a cross-sectional view of a main part of a sensor chip according to Example 5.
  • FIG. 10 is a cross-sectional view of main parts of a sensor chip according to a modification of Example 5.
  • the constituent elements are not necessarily indispensable unless otherwise specified and clearly considered essential in principle. Needless to say.
  • hatching may be added even if it is a plan view so as to make the drawing easy to see, and even if it is a cross-sectional view, hatching may be omitted so as to make the drawing easy to see. is there.
  • the size of each part does not correspond to the actual device, and a specific part may be displayed relatively large for easy understanding of the drawing. Even when the cross-sectional view and the plan view correspond to each other, a specific part may be displayed relatively large in order to make the drawing easy to understand.
  • the thermal fluid flow sensor according to the first embodiment will be described.
  • the thermal fluid flow sensor according to the first embodiment is a thermal resistance type thermal fluid flow sensor that detects a fluid flow rate by using a characteristic that a resistance value of a resistor changes according to temperature.
  • FIG. 1 is a plan view of an essential part of the sensor chip according to the first embodiment.
  • FIG. 2 is a cross-sectional view of the main part of the sensor chip taken along the line AA ′ in FIG.
  • FIG. 5 is a cross-sectional view of a main part of the intake passage of the internal combustion engine to which the thermal fluid flow sensor according to the first embodiment is attached.
  • a sensor chip 1 of a thermal fluid flow sensor includes a semiconductor substrate 2 made of single crystal Si (silicon) and a diaphragm portion from which a part of the semiconductor substrate 2 is removed for flow rate detection.
  • a downstream resistance temperature detector 5 disposed on the downstream side of the first heating resistor and a first resistance temperature detector 7 for measuring the temperature of the first heating resistor 3 are formed.
  • the first heating resistor 7 is provided between the first heating resistor 3 and the upstream resistance bulb 4 and between the first heating resistor 3 and the downstream resistance bulb 5 respectively. Has been placed.
  • the first heating resistor 3, the upstream temperature measuring resistor 4, the downstream temperature measuring resistor 5, and the first heating resistor temperature measuring resistor 7 are covered with the second insulating film 11, and the upstream temperature measuring resistor 7 is covered.
  • a second heat generating resistor 6 made of, for example, the same material as that of the first heat generating resistor 4 is formed above the resistor 4 via the second insulating film 11. That is, a part of the second heating resistor 6 overlaps with the upstream resistance temperature detector 4 in plan view.
  • the second heating resistor 6 is covered with a third insulating film 12. Note that the second heating resistor 6 may be formed of a material different from that of the first heating resistor 3.
  • the first insulating film 10, the second insulating film 11, and the third insulating film 12 are, for example, a single layer film made of silicon oxide, a single layer film made of silicon nitride, a laminated film in which silicon oxide and silicon nitride are stacked, or silicon oxide And a laminated film in which a plurality of silicon nitride layers are alternately stacked.
  • each resistor (the first heating resistor 3, the upstream temperature measuring resistor 4, the downstream temperature measuring resistor) is removed.
  • each resistor (the first heating resistor 3, the upstream temperature measuring resistor 4, the downstream temperature measuring resistor 5, the second heating resistor 6 and the first heating resistor) is used.
  • a metal film made of, for example, Al (aluminum) may be provided on each electrode pad 8 of the body temperature measuring resistor 7).
  • an organic insulating film may be formed on the third insulating film 12, and in that case, at least each resistor (first heating resistor 3, upstream temperature measuring resistor 4, downstream temperature measuring resistor 5).
  • the organic insulating film above the second heating resistor 6 and the first heating resistor temperature measuring resistor 7) is removed, or the entire organic insulating film above the diaphragm portion 9 is removed.
  • the second heating resistor 6 is located closer to the upstream temperature sensing resistor 4 than the first heating resistor 3 and is provided above the location where heat transfer is good, for example, the upstream temperature sensing resistor 4. Yes.
  • the thickness of the second insulating film 11 is The distance between the heating resistor 6 and the upstream temperature measuring resistor 4 is determined.
  • the thickness T1 of the second insulating film 11 sandwiched between the upper surface of the first insulating film 10 and the lower surface of the third insulating film 12 is, for example, in the range of 0.1 ⁇ m to 1 ⁇ m.
  • the upstream side resistance thermometer 4 and the downstream side resistance thermometer 5 are provided so as to be line-symmetric with respect to the direction of intake air with the first heating resistor 3 interposed therebetween.
  • the sensor chip 1 in which a part of the second heating resistor 6 is overlapped with the upstream temperature measuring resistor 4 in the plan view is illustrated, but the present invention is not limited to this, and the overlapping is described above. Is not a requirement.
  • the midpoint of the straight line connecting the first heating resistor 3 and the second heating resistor 6 is located upstream of the midpoint of the straight line connecting the upstream resistance temperature detector 4 and the downstream resistance temperature detector 5.
  • the second heating resistor 6 only needs to be formed. The same applies to Examples 2 and 3 described later.
  • the sensor module 13 has a support substrate 14 and a recess 15 formed in the support substrate 14.
  • the sensor chip 1 is fixed inside the recess 15 with an adhesive 16, and the control circuit chip 17 is mounted on the support substrate 14 other than the region where the recess 15 is formed. Further, a part of the electrode pads 18 of the control circuit chip 17 and the electrode pads 8 of the sensor chip 1 are electrically connected via bonding wires 19a. Further, another part of the electrode pads (electrode pads for input / output terminals to the outside) 18 and the external input / output terminals 20 formed on the support substrate 14 are connected via bonding wires 19b. Are electrically connected.
  • the electrode pad 8 of the sensor chip 1 and the electrode pad 18 of the control circuit chip 17 are easily corroded, the electrode pad 8, the electrode pad 18 and the control circuit chip 17 are covered with a resin 21 for preventing corrosion.
  • the diaphragm portion 9 serves as a fluid detection portion, the surface side of the diaphragm portion 9 is not covered with the corrosion preventing resin 21, and the back surface side of the diaphragm portion 9 fixed to the support substrate 14 is the adhesive 16. Thus, the diaphragm portion 9 is prevented from being sealed.
  • the thermal fluid flow sensor 22 includes a body 23, a sub passage 24 formed in the body 23, a support body 25 that fixes the sensor module 13, and a support body cover 26. And have.
  • the sensor module 13 is fixed to the thermal fluid flow sensor 22 by the support body 25 and the support body cover 26 so that the intake air 29 flows to the diaphragm section 9 of the sensor chip, which is the intake flow rate detection section of the sensor module 13. .
  • the thermal fluid flow sensor 22 is attached to the intake pipe 27 so as to penetrate through the intake pipe 27 and intake air 29 flowing into the main passage 28 is taken into the sub-passage 24.
  • the auxiliary passage 24 is illustrated in a simplified manner in parallel and linearly with the intake pipe 27, but the auxiliary passage 24 may have a curved or branched shape in the body 23. Good.
  • the second heating resistor 6 is formed on the upstream resistance temperature detector 4 via the second insulating film 11, but this is not limitative. It is not something.
  • the second heating resistor 6 is formed on the first insulating film 10, the second heating resistor 6 is covered with the second insulating film 11, and the first insulating film 11 is covered with the first insulating film 11.
  • the heating resistor 3, the upstream temperature measuring resistor 4, the downstream temperature measuring resistor 5, and the first heating resistor for temperature measuring resistor 7 may be formed.
  • the upstream resistance temperature detector 4 is disposed above the second heating resistor 6 via the second insulating film 11. That is, a part of the second heating resistor 6 overlaps with the upstream resistance temperature detector 4 in plan view.
  • the heating resistor 6 may be formed.
  • FIG. 7 is a circuit diagram of the thermal fluid flow sensor according to the first embodiment.
  • FIG. 8 is an operation flowchart of the thermal fluid flow sensor when the thermal fluid flow sensor according to the first embodiment is incorporated in an automobile.
  • the temperature of the first heating resistor 3 is monitored by the temperature measuring resistor 7 for the first heating resistor, and the voltage or current is controlled by the controller 34 so as to reach a desired temperature.
  • the upstream resistance temperature detector 4 and the downstream resistance temperature detector 5 form a bridge circuit with the bridge resistor 30 provided in the sensor chip or the control circuit chip other than the diaphragm portion, and the upstream resistance temperature detector A predetermined voltage (Vref) is applied between 4 and the downstream resistance temperature detector 5.
  • an analog / digital converter After connecting the differential voltage between the midpoint of the upstream resistance temperature detector 4 and the bridge resistor 30 and the midpoint of the downstream resistance temperature detector 5 and the bridge resistor 30 to the amplifier 31, an analog / digital converter The digital conversion is performed by a circuit such as (ADC) 33 and the like and output to an electronic control unit (Electronic Control Unit: ECU) 36.
  • ADC Analog to Digital Converter
  • a comparator 32 for determining whether the zero point is within the allowable range is provided after the amplifier 31.
  • the comparator 32 is out of the allowable range, the voltage is applied to the second heating resistor 6. Is applied to heat the upstream resistance temperature detector 4.
  • the resistance values of the upstream resistance temperature detector 4, the downstream resistance temperature detector 5 and the bridge resistor 30 heated by the first heating resistor 3 are designed to be equal to each other.
  • the output to the control device 36 becomes zero, and the analog / digital converter 33 converts the correlation between the intake air flow rate and the differential voltage based on this state and outputs the result.
  • a fluid flow rate is output by a thermal fluid flow sensor incorporated in an electronically controlled fuel injection device of an automobile.
  • step S1 power is supplied to the thermal fluid flow sensor and the electronic control unit 36 (step S1).
  • “Before starting the engine” means, for example, a state in which a key is simply inserted into a key cylinder.
  • step S2 the zero point when there is no wind is confirmed by the comparator 32, and it is determined whether or not the zero point is within the allowable range (step S2).
  • step S3 If it is within the allowable range (OK), the engine is started (step S3). Then, the intake air flows (step S4), and the intake flow rate is output (step S5).
  • the second heating resistor 6 is instantaneously supplied with power, and after the second heating resistor 6 is stopped (step S6), the zero point is confirmed again by the comparator 32, It is determined whether or not the zero point is within an allowable range (step S2). That is, the operation flow of the thermal fluid flow sensor in the first embodiment has a zero point correction mode in which the zero point can be within an allowable range.
  • the present invention is not limited to this.
  • the engine stops when the car stops with a signal or the like, and then the engine restarts.
  • the zero point can be corrected according to the operation flow shown in FIG.
  • the zero point is confirmed by the comparator 32, and when it is out of the allowable range, it is calculated from the changed differential voltage, and the upstream side resistance temperature detector 4 and the downstream side resistance temperature detector 5 are calculated.
  • the second heating resistor 6 is slightly heated by the amount of resistance change. Then, the zero point is confirmed again by the comparator 32, and after correcting the zero point within the allowable range, the engine is started while supplying power while fixing the temperature of the second heating resistor 6 and outputs the intake air flow rate. .
  • the resistance value of the upstream resistance temperature detector 4 and the resistance value of the downstream resistance temperature detector 5 are designed to be equal to each other.
  • a thermal fluid flow sensor may be manufactured in which the zero point during no wind exceeds the allowable range. Even for such a thermal fluid flow sensor, the second heating resistor 6 is used to improve the balance between the resistance value of the upstream resistance temperature detector 4 and the resistance value of the downstream resistance temperature detector 5. Since the zero point can be corrected by this, the manufacturing yield of the thermal fluid flow sensor is improved and the manufacturing cost is reduced.
  • FIG. 9 is a graph showing the relationship between the heating temperature and the heating time required for a constant resistance change (several ⁇ ) when the resistance temperature detector is directly heated in the thermal fluid flow sensor according to the first embodiment.
  • the heating time can be reduced to about 1/10 by increasing the heating temperature to 100 ° C.
  • the resistance change of the downstream resistance temperature detector 5 proceeds faster than the upstream resistance temperature detector 4 due to the heating of the first heating resistor 3 along with the usage time. Therefore, the zero point fluctuates.
  • the heating temperature of the second heating resistor 6 is equal to the heating temperature of the first heating resistor 3
  • the same time as the use time of the thermal fluid flow sensor is set to the upstream resistance temperature detector.
  • the heating temperature of the second heating resistor 6 is set higher than at least the heating temperature of the first heating resistor 3, and the upstream of the resistance value of the downstream resistance temperature detector 5 is increased in a short time.
  • the resistance value of the side resistance thermometer 4 is brought close to and the zero point is corrected within the allowable range. For example, when the first heating resistor 3 is heated at 200 ° C., the zero point can be corrected in about 1/1000 time by heating the second heating resistor 6 at 500 ° C. .
  • the change in the resistance value is small (for example, less than 1 ⁇ ). It is not necessary to heat the body 6 for a long time. Further, by making the pattern of the second heating resistor 6 (heat generating area) smaller than the pattern of the first heating resistor 3 (heat generating area), power consumption can be reduced and the zero point can be corrected efficiently. Is possible.
  • the fluctuation of the zero point of the thermal fluid flow sensor can be instantaneously suppressed within the allowable range regardless of the usage time of the engine. It is possible to maintain the reliability of the thermal fluid flow sensor.
  • the difference between the sensor chip 1A according to the second embodiment and the sensor chip 1 according to the first embodiment is that the second heating resistor 6 is disposed above the downstream resistance temperature detector 5 via the second insulating film 11. The same resistor 35 is formed.
  • FIG. 10 is a plan view of the main part of the sensor chip according to the second embodiment.
  • FIG. 11 is a cross-sectional view of the main part of the sensor chip taken along the line CC ′ of FIG.
  • the residual stress in the diaphragm portion 9 varies depending on the laminated material. Therefore, when the second heating resistor 6 is formed only above the upstream resistance temperature detector 4 via the second insulating film 11, the balance of the residual stress of the sensor chip 1A may be deteriorated.
  • the first heating resistor 3 is sandwiched, Since it is possible to maintain the objectivity of the structure on the upstream side and the downstream side, the balance of the residual stress of the sensor chip 1A becomes good. Thereby, the intensity
  • a part of the resistor 35 overlaps with the downstream resistance temperature detector 5, and the second heating resistor 6 and the resistor are in line symmetry with the first heating resistor 3 in the direction of intake air flow.
  • the body 35 is provided.
  • the resistor 35 has an independent electrode pad 8 and is normally connected to the ground.
  • the second heat generating resistor 6 and the resistor 35 are provided so as to be symmetric with respect to the flow direction of the intake air with the first heat generating resistor 3 interposed therebetween. Even when the mounting specifications are changed, it is possible to obtain the effect of suppressing the fluctuation of the zero point of the thermal fluid flow sensor within the allowable range only by changing the connection of the resistor 35 and the connection of the second heating resistor 6. it can.
  • the resistor 35 can be used as a third heating resistor, which can be heated independently of the second heating resistor 6 and used to correct the zero point when there is no wind.
  • the difference between the sensor chip 1B according to the third embodiment and the sensor chip 1 according to the first embodiment is that the first heating resistor 3 is formed of the same heat-resistant material as the second heating resistor 6. It is that you are.
  • the high heat resistant material is a refractory metal such as W (tungsten) or Mo (molybdenum).
  • FIG. 12 is a cross-sectional view of the main part of the sensor chip according to the third embodiment.
  • the first heating resistor measurement is arranged between the upstream resistance temperature detector 4 and the downstream resistance temperature detector 5 along the upstream resistance temperature detector 4 and the downstream resistance temperature detector 5, respectively.
  • a temperature resistor 7 is formed.
  • the upstream resistance temperature detector 4, the downstream resistance temperature detector 5, and the first heating resistor resistance temperature detector 7 are covered with a second insulating film 11.
  • a first heating resistor 3, a second heating resistor 6, and a resistor 35 are formed on the second insulating film 11, and the second heating resistor 6 is formed above the upstream temperature measuring resistor 4.
  • a resistor 35 is formed above the downstream resistance temperature detector 5. That is, in plan view, a part of the second heating resistor 6 overlaps with the upstream temperature measuring resistor 4, and a part of the resistor 35 overlaps with the downstream temperature measuring resistor 4.
  • first heating resistor 3 made of the same layer and the same material as the second heating resistor 6 is formed between the second heating resistor 6 and the resistor 35.
  • first temperature measuring resistors 7 for the first heating resistor are arranged on the upstream side and the downstream side of the first heating resistor 3, respectively.
  • the first heating resistor 3 has the same layer structure as the second heating resistor 6 and is formed of a high heat resistant material, resistance deterioration due to heat can be suppressed, so that the sensor chip 1B Reliability can be improved.
  • the difference between the sensor chip 51 according to the fourth embodiment and the sensor chip 1 according to the first embodiment is a temperature measurement method.
  • the temperature measuring method of the first embodiment described above is a thermal resistance method that uses the characteristic that the resistance value changes with temperature.
  • the temperature measuring method of the fourth embodiment is a thermocouple method using a temperature difference between the semiconductor substrate (cold spot) and the vicinity of the first heating resistor (hot spot).
  • FIG. 13 is a plan view of the main part of the sensor chip according to the fourth embodiment.
  • 14 is a cross-sectional view of the main part of the sensor chip taken along the line DD ′ of FIG.
  • a sensor chip 51 using a thermocouple includes a semiconductor substrate 65 made of single crystal Si (silicon) and a diaphragm portion 64 from which a part of the semiconductor substrate 65 is removed for flow rate detection. .
  • a first heating resistor 52 is provided on the semiconductor substrate 65 in the vicinity of the center of the diaphragm portion 64, and the upstream thermocouple 53 is symmetrical with respect to the direction of intake air flow with the first heating resistor 52 interposed therebetween. And a downstream thermocouple 54 are disposed.
  • the second heating resistor 55 is disposed above the upstream thermocouple 53, and the resistor 56 is disposed above the downstream thermocouple 54.
  • the second heating resistor 55 and the resistor 56 are:
  • the first heating resistor 52 is arranged so as to be line symmetric with respect to the direction of intake air flow.
  • the first heating resistor 52, the upstream thermocouple 53, the downstream thermocouple 54, the second heating resistor 55, and a plurality of electrode pads 57 exposing a part of the resistor 56 are provided.
  • the plurality of electrode pads 57 are electrically connected to the control circuit chip via bonding wires.
  • the upstream side thermocouple 53 and the downstream side thermocouple 54 output a differential voltage by the bridge circuit.
  • an upstream thermocouple lower layer wiring 58 and a downstream thermocouple lower layer wiring 59 are formed on a semiconductor substrate 65 via a first insulating film 66, and an upstream thermocouple lower layer wiring 58 and The downstream thermocouple lower layer wiring 59 is covered with the second insulating film 67.
  • thermocouple upper layer wiring 62 and a downstream thermocouple upper layer wiring 63 are formed on the second insulating film 67, and the upstream thermocouple upper layer wiring 62 is disposed above the upstream thermocouple lower layer wiring 58, A downstream thermocouple upper layer wiring 63 is disposed above the downstream thermocouple lower layer wiring 59.
  • the upstream thermocouple lower layer wiring 58 and the upstream thermocouple upper layer wiring 62 constitute an upstream thermocouple 53, and the downstream thermocouple lower layer wiring 59 and the downstream thermocouple upper layer wiring 63 constitute a downstream thermocouple 54. Is done.
  • the upstream side thermocouple lower layer wiring 58 and the upstream side thermocouple upper layer wiring 62 pass through the second insulating film 67 in the vertical direction, and a hot spot connection plug 60 and a cold spot connection plug (not shown). ) Are alternately connected.
  • the number of the upstream thermocouple lower layer wirings 58 and the upstream thermocouple upper layer wirings 62 that are alternately connected are equal.
  • the downstream thermocouple 54 the downstream thermocouple lower layer wiring 59 and the downstream thermocouple upper layer wiring 63 penetrate the second insulating film 67 in the vertical direction, and the hot spot connection plug 60 and the cold spot connection plug 61. Are connected alternately.
  • the numbers of the downstream thermocouple lower layer wiring 59 and the downstream thermocouple upper layer wiring 63 that are alternately connected are equal.
  • the upstream thermocouple 53 and the downstream thermocouple 54 are covered with a third insulating film 68.
  • a first heating resistor 52, a second heating resistor 55, and a resistor 56 are formed on the third insulating film 68, and the second heating resistor 55 is disposed above the upstream thermocouple 53, A resistor 56 is disposed above the downstream thermocouple 54.
  • a first heating resistor 52 is formed between the second heating resistor 55 and the resistor 56. Further, the first heating resistor 52, the second heating resistor 55, and the resistor 56 are covered with a fourth insulating film 69. Although illustration is omitted, the fourth insulating film 69 is opened in the electrode pad 57.
  • the first insulating film 66, the second insulating film 67, the third insulating film 68, and the fourth insulating film 69 are, for example, a single layer film made of silicon oxide, a single layer film made of silicon nitride, and a stack of silicon oxide and silicon nitride. Or a laminated film in which a plurality of silicon oxides and silicon nitrides are alternately laminated.
  • a temperature measuring resistor for the first heating resistor or a thermocouple for the first heating resistor for measuring the temperature of the first heating resistor 52 is provided in the vicinity of the first heating resistor 52 to perform temperature control. Also good.
  • the downstream-side thermocouple 54 changes due to the heat effect with the use time. This is because the downstream thermocouple lower layer wiring 59 and the downstream thermocouple upper layer wiring 63 change in resistance due to thermal effects.
  • the gradient in the impurity concentration contained in the polycrystalline Si (silicon) film is caused by thermal effects. Occurs and the hot spot shifts.
  • the value of the upstream thermocouple 53 can be brought close to the value of the downstream thermocouple 54 by heating the second heating resistor 55.
  • the difference between the sensor chip 51A according to the fifth embodiment and the sensor chip 51 according to the fourth embodiment described above is that the first heating resistor 52, the first heating resistor 55, and the resistor 56 are made of different layers. It is forming. That is, the first heating resistor 55 is disposed between the upstream thermocouple upper layer wiring 62 and the upstream thermocouple lower layer wiring 58 of the upstream thermocouple 53, and the resistor 56 is disposed downstream of the downstream thermocouple 54. It is arranged between the thermocouple upper layer wiring 63 and the downstream thermocouple lower layer wiring 59.
  • FIG. 15 is a cross-sectional view of a main part of the sensor chip according to the fifth embodiment.
  • the upstream thermocouple lower layer wiring 58 and the downstream thermocouple lower layer wiring 59 are formed on the semiconductor substrate 65 via the first insulating film 66, and the upstream thermocouple lower layer wiring 58 and The downstream thermocouple lower layer wiring 59 is covered with a second insulating film 67.
  • a second heating resistor 55 and a resistor 56 are formed on the second insulating film 67, and the second heating resistor 55 is disposed above the upstream thermocouple lower layer wiring 58, and the downstream thermocouple lower layer wiring is formed.
  • a resistor 56 is disposed above 59.
  • the second heating resistor 55 and the resistor 56 are covered with a fifth insulating film 70.
  • thermocouple upper layer wiring 62 and a downstream thermocouple upper layer wiring 63 are formed on the fifth insulating film 70, and the upstream thermocouple upper layer wiring 62 is disposed above the second heating resistor 55, and the resistance A downstream thermocouple upper layer wiring 63 is disposed above the body 56.
  • the fifth insulating film 70 insulates the second heating resistor 55 from the upstream thermocouple upper layer wiring 62 and the resistor 56 from the downstream thermocouple upper layer wiring 63.
  • the upstream-side thermocouple lower layer wiring 58 and the upstream-side thermocouple upper-layer wiring 62 pass through the second insulating film 67 and the fifth insulating film 70 in the vertical direction and the cold spot connection plug 60 and the cold spot. They are alternately connected by connection plugs (not shown).
  • the number of the upstream thermocouple lower layer wirings 58 and the upstream thermocouple upper layer wirings 62 that are alternately connected are equal.
  • the downstream thermocouple lower layer wiring 59 and the downstream thermocouple upper layer wiring 63 pass through the second insulating film 67 and the fifth insulating film 70 in the vertical direction and the hot spot connection plug 60.
  • thermocouple lower layer wiring 59 and the downstream thermocouple upper layer wiring 63 that are alternately connected are equal.
  • the upstream thermocouple 53 and the downstream thermocouple 54 are covered with a third insulating film 68.
  • a first heating resistor 52 is formed on the third insulating film 68, and the first heating resistor 52 is formed so as to be positioned between the upstream thermocouple 53 and the downstream thermocouple 54 in plan view. Yes. Further, the first heating resistor 52 is covered with a fourth insulating film 69. Although illustration is omitted, the fourth insulating film 69 is opened in the electrode pad 57.
  • the resistor 56 is also formed between the downstream thermocouple upper layer wiring 63 and the downstream thermocouple lower layer wiring 59 of the downstream thermocouple 54.
  • the first heating resistor 52 is formed on the third insulating film 68.
  • the present invention is not limited to this.
  • a first heating resistor 52 made of a high breakdown voltage material, for example, a refractory metal, in the same layer as the second heating resistor 55 may be formed on the second insulating film 67. Even with the sensor chip 51B having such a structure, the power consumption of the second heating resistor 55 necessary for zero point correction can be suppressed.
  • the present invention includes at least the following embodiments.
  • a flow sensor for measuring a flow rate of a fluid to be measured A first heating resistor; A first temperature measuring thermocouple provided on the downstream side of the first heating resistor, separated from the first heating resistor; A second temperature measuring thermocouple provided on the upstream side of the first heating resistor, spaced apart from the first heating resistor; A second heating resistor provided on the second temperature measuring thermocouple via an insulator; Have A flow rate sensor that heats the second temperature measuring thermocouple by heat generation of the second heating resistor.
  • Appendix 2 In the flow sensor according to appendix 1, A flow rate sensor, wherein a distance between the second heating resistor and the second temperature measuring thermocouple is shorter than a distance between the first heating resistor and the second temperature measuring thermocouple.

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

Abstract

L'invention vise à obtenir un capteur de débit ayant une grande sensibilité et une grande précision. Afin de résoudre le problème susmentionné, un capteur de débit selon la présente invention comprend : une première résistance chauffante (3) ; une résistance de mesure de température amont (4), qui est disposée en amont de la première résistance chauffante (3) en étant séparée de la première résistance chauffante (3) ; et une résistance de mesure de température aval (5), qui est disposée en aval de la première résistance chauffante (3) en étant séparée de la première résistance chauffante (3). Le capteur de débit comprend également une seconde résistance chauffante (6) au-dessus de la résistance de mesure de température amont (4). ladite seconde résistance chauffante chauffe la résistance de mesure de température amont (4) par l'intermédiaire d'un film isolant. La résistance de mesure de température amont (4) est chauffée en amenant la seconde résistance chauffante (6) à générer de la chaleur en fournissant de l'énergie, et une différence entre une valeur de résistance de la résistance de mesure de température amont (4) et une valeur de résistance de la résistance de mesure de température aval (5) est définie dans une plage admissible, ce qui permet d'effectuer une correction de point zéro du capteur de débit.
PCT/JP2016/081126 2015-11-18 2016-10-20 Capteur de débit WO2017086086A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2015-225320 2015-11-18
JP2015225320A JP6532810B2 (ja) 2015-11-18 2015-11-18 流量センサ

Publications (1)

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WO2017086086A1 true WO2017086086A1 (fr) 2017-05-26

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JP (1) JP6532810B2 (fr)
WO (1) WO2017086086A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07198439A (ja) * 1993-11-24 1995-08-01 Ricoh Co Ltd 感熱式流速センサ
JP2004093189A (ja) * 2002-08-29 2004-03-25 Mitsubishi Electric Corp 熱式流量検出装置
JP2008286604A (ja) * 2007-05-16 2008-11-27 Hitachi Ltd 熱式流量計

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07198439A (ja) * 1993-11-24 1995-08-01 Ricoh Co Ltd 感熱式流速センサ
JP2004093189A (ja) * 2002-08-29 2004-03-25 Mitsubishi Electric Corp 熱式流量検出装置
JP2008286604A (ja) * 2007-05-16 2008-11-27 Hitachi Ltd 熱式流量計

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JP6532810B2 (ja) 2019-06-19
JP2017096632A (ja) 2017-06-01

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