WO2016002439A1 - Débitmètre d'air thermique - Google Patents

Débitmètre d'air thermique Download PDF

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Publication number
WO2016002439A1
WO2016002439A1 PCT/JP2015/066423 JP2015066423W WO2016002439A1 WO 2016002439 A1 WO2016002439 A1 WO 2016002439A1 JP 2015066423 W JP2015066423 W JP 2015066423W WO 2016002439 A1 WO2016002439 A1 WO 2016002439A1
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WO
WIPO (PCT)
Prior art keywords
plate
sensor chip
thermal air
flow meter
air passage
Prior art date
Application number
PCT/JP2015/066423
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English (en)
Japanese (ja)
Inventor
公俊 緒方
石塚　典男
忍 田代
徳安　昇
Original Assignee
日立オートモティブシステムズ株式会社
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 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 WO2016002439A1 publication Critical patent/WO2016002439A1/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

Definitions

  • the present invention relates to a flow meter that measures the flow rate of a gas to be measured, and more particularly to a thermal air flow meter that measures the intake air amount of an internal combustion engine.
  • a thermal air flow meter that measures the gas flow rate has a flow rate detection unit for measuring the flow rate, and measures the gas flow rate by transferring heat between the flow rate detection unit and the gas to be measured. It is configured as follows.
  • the flow rate measured by the thermal air flow meter is widely used as an important control parameter in various apparatuses.
  • a feature of the thermal air flow meter is that a gas flow rate, for example, a mass flow rate can be measured with relatively high accuracy compared to other types of flow meters.
  • a thermal air flow meter that measures the amount of intake air led to an internal combustion engine includes a sub-passage that takes in a part of the intake air amount and a sensor chip disposed in the sub-passage, and a flow rate detection unit provided in the sensor chip is covered. By performing heat transfer with the measurement gas, the state of the gas to be measured flowing through the sub-passage is measured, and an electric signal representing the amount of intake air guided to the internal combustion engine is output.
  • the sensor chip has a partial cavity formed in a semiconductor substrate by a semiconductor machining technique and a thin film part provided so as to cover the cavity.
  • the thin film part is called a diaphragm, and the response speed of the thermal air flow meter can be further increased by forming the flow rate detection part on the diaphragm.
  • a technique for suppressing the stress generated on the diaphragm is required. Such a technique is disclosed in Patent Document 1, for example.
  • a sensor chip having a diaphragm structure composed of a thin film portion which is a flow rate detection portion is mounted on a plate, and a cavity on the back surface of the diaphragm and outside air are passed through an air passage and an air hole formed in the plate.
  • the diaphragm surface is disposed in the sub-passage for measuring the flow rate, and the air hole connecting the rear surface of the diaphragm and the outside air is formed as a sub-port. Place outside the aisle.
  • An object of the present invention is to provide a thermal air flow meter with high measurement accuracy.
  • the sensor chip and the plate are molded with resin so that a diaphragm of the sensor chip and a part of the plate are exposed, and the plate is In the molding, the plate has a groove or a thinned portion that is partially thinned outside the sensor chip mounting surface area that receives a pressing load from the sensor chip.
  • FIG. 1 is a plan view of a mounted part before the sensor assembly 10 is formed
  • FIG. 2 is a plan view after the sensor assembly 10 is formed
  • FIG. 3A is a cross-sectional view along AA in FIG. 2
  • FIG. FIG. 3 is a sectional view taken along line BB in FIG.
  • the sensor assembly 10 includes a lead frame 1, a plate 2, an LSI 3, and a sensor chip 4, and these are covered with a first resin 24 as shown in FIG. 2.
  • FIG. 1 is a plan view of a mounted part before the sensor assembly 10 is formed
  • FIG. 2 is a plan view after the sensor assembly 10 is formed
  • FIG. 3A is a cross-sectional view along AA in FIG. 2
  • FIG. FIG. 3 is a sectional view taken along line BB in FIG.
  • the sensor assembly 10 includes a lead frame 1, a plate 2, an LSI 3, and a sensor chip 4, and these are covered with a first resin 24 as shown in FIG. 2.
  • FIG. 1 is a
  • the plate 2 is bonded to the lead frame 1 with the adhesive tape 5, and the LSI 3 and the sensor chip 4 are further bonded to the plate 2 with the adhesive tape 6 and the adhesive tape 7.
  • Glue a shape having a longitudinal direction and a lateral direction, such as a rectangle, and the sensor chip 4 and the LSI 3 are arranged on the plate 2 so as to be aligned in the longitudinal direction.
  • the plate 2 may be made of glass or resin.
  • Next, between the LSI 3 and the sensor chip 4 and between the LSI 3 and the lead frame 1 are electrically connected using gold wires 8 and 9 by wire bonding. These are sealed with the first resin 24 to complete the sensor assembly 10.
  • the sensor assembly 10 has a partially exposed structure in which the first resin 24 is not present in the diaphragm portion 27 of the sensor chip 4.
  • FIG. 4 is a cross-sectional view when the mounted component is clamped by the upper mold 16 and the lower mold 15 in the manufacturing process of the sensor assembly 10 having the partially exposed structure.
  • the sensor assembly 10 is manufactured by pouring the first resin 24 into the mold.
  • the diaphragm portion 27 of the sensor chip 4 By pressing the diaphragm portion 27 of the sensor chip 4 with the upper mold 16, inflow of the resin at the time of resin sealing is prevented.
  • the sensor assembly 10 has a partially exposed structure in which the diaphragm 27 is exposed.
  • FIG. 5 is a front view when the sensor assembly 10 is mounted on the housing 11 including the sub-passage 12, and FIG. 6 is a cross-sectional view taken along the line AA in FIG.
  • the housing 11 includes a sub-passage 12 for guiding the air flowing through the main passage to the sensor chip 4, holding portions 20 and 21 of the sensor assembly 10 (to become side walls of the sub-passage), and a holding portion 14 of the lead frame 1.
  • the sensor assembly 10 is fixed simultaneously with the formation of the housing 11 made of the second resin. At this time, the sensor chip 4 having the flow rate detection unit needs to measure the air flow rate, and thus is disposed in the sub-passage 12.
  • FIG. 7 is a front view of the plate 2, and a CC sectional view and a DD sectional view on FIG.
  • the plate 2 has a thinned portion 30 outside the mounting area 29 of the sensor chip 4 and on the back surface side (lead frame side).
  • the thinned portion 30 in the first embodiment is provided up to the end of the plate 2 in the short direction.
  • the sensor chip 4 is pushed by the upper mold 16 in order to form a partially exposed structure of the diaphragm portion 27.
  • the surface of the plate 2 receives a pressing load from the sensor chip 4
  • the back surface of the plate 2 receives a reaction force accompanying the pressing load from the lead frame 1.
  • the contact area between the plate 2 and the lead frame 1 is larger than the contact area between the plate 2 and the sensor chip 4 as shown in FIG. Since the force is distributed, bending deformation occurs in the plate 2.
  • the deformation of the sensor chip 4 is promoted, and stress is generated in the diaphragm portion 27, which may reduce the measurement accuracy.
  • the thinned portion 30 outside the mounting area 29 of the sensor chip 4 on the plate 2
  • the difference between the contact area between the plate 2 and the sensor chip 4 and the contact area between the plate 2 and the lead frame is reduced. It can be reduced in the vicinity of the sensor chip mounting area 29, and the bending deformation of the plate can be suppressed.
  • FIG. 7 shows a particularly preferable configuration of the thinned portion 20.
  • the thinned portion 30 is provided on the back side (lead frame side) of the plate 2 so that the side surface on the sensor mounting region side of the thinned portion 30 and the side surface of the sensor chip 4 are substantially flush with each other.
  • the contact areas on the front and back surfaces of the plate 2 are substantially equal, and the reaction force received from the lead frame 1 is the sensor chip mounting area. Concentrate in the vicinity of 29. Therefore, the bending deformation of the plate 2 as shown in FIG. 8 can be further suppressed, and the flow rate measurement accuracy can be maintained with higher accuracy.
  • the air passage 13 formed in the plate 2 may be configured as one, or the outlet opening 17 may be formed directly below the mounting area 29 of the sensor chip 4 as shown in FIG. Needless to say, the same effects can be obtained.
  • the thinned portion 30 formed on the plate 2 is arranged outside the mounting region 29 of the sensor chip 4 in the short direction of the plate and as shown in FIGS. It is the point arrange
  • the plate 2 is produced, for example, by fragmenting wafer-like glass or resin. However, if the side surface of the plate 2 that is a cut surface is thin, the plate 2 is likely to be chipped when fragmented, and the yield may be reduced.
  • the thinned portion 30 is provided on the inner side of the side surface of the plate 2, it is possible to suppress the thinning of the side surface of the plate 2 and to prevent the yield from being reduced in size. Needless to say, this configuration also achieves the same effects as the previous embodiments.
  • the thinned portion 30 provided on the plate 2 is connected to the air passage 13.
  • the configuration different from the first and second embodiments is that the plate 2 is formed so that the side surface of the mounting area 29 of the sensor chip 4 and the side surface of the plate 2 are flush with each other as shown in FIG. is there.
  • the plate 2 is formed so that the side surface of the mounting area 29 of the sensor chip 4 and the side surface of the plate 2 are flush with each other only in the vicinity of the side surface of the mounting area 29.
  • the plate 2 has a configuration in which the width in the short direction of the sensor mounting region 29 is equal to the width in the short direction (also referred to as a flow rate detection direction) of the sensor chip. Needless to say, this configuration also achieves the same effects as the previous embodiments.
  • the bending deformation of the plate 2 as shown in FIG. 8 decreases in proportion to the cube of the plate thickness. Therefore, when the depth d of the air passage 13 is increased, the thickness of the plate 2 immediately above the air passage is reduced and bending deformation is increased. Therefore, as shown in FIG. 17, bending deformation can be suppressed by increasing the thickness T of the plate 2 and decreasing the depth d of the air passage 13. In order to suppress the bending deformation, it is desirable that d ⁇ T / 2. On the other hand, if the depth d of the air passage 13 is smaller than the thickness t of the adhesive sheet 5 that bonds the plate 2 and the lead frame 1, the air passage 13 may be blocked by the adhesive sheet 5 when the sensor assembly 10 is manufactured.
  • the depth d of the air passage 13 is preferably larger than the thickness t of the adhesive sheet 5 (t ⁇ d). From the above, it is preferable that the thickness T of the plate 2, the depth d of the air passage, and the thickness t of the adhesive sheet satisfy t ⁇ d ⁇ T / 2.
  • FIG. 18 is a sectional view of the plate 2 and an enlarged view of the air passage 13.
  • the air passage 13 and the thinned portion 30 of the plate 2 are formed by sandblasting.
  • minute cracks and scratches as shown in the enlarged view of FIG. It occurs on the surface of the passage 13 and the thinned portion 30.
  • the surface treatment such as hydrofluoric acid treatment can remove minute cracks and scratches generated when the air passage 13 and the thinned portion 30 are formed, thereby reducing the stress concentration. it can.
  • the present invention is also effective in a structure in which the back surface of the diaphragm portion 27 is sealed without providing the air passage 13.
  • a pressure difference is generated on the front and back surfaces of the diaphragm portion 27 due to expansion and contraction of air due to a temperature change during flow rate measurement, and the diaphragm portion 27 is warped and deformed due to this pressure difference. It can be a flow measurement error.
  • the deformation of the plate can be suppressed. It becomes possible. Therefore, even when the diaphragm portion 27 is sealed, the temperature change at the time of flow rate measurement is measured, and the measurement error due to the warp deformation generated in the diaphragm portion 27 is corrected, thereby suppressing a decrease in measurement accuracy. Is possible.
  • the structure different from the previous embodiment is that the air passage 13 provided in the plate 2 is provided inside the region 31 where the sensor chip 4 presses the plate 2, and the air passage 13 is formed only in the longitudinal direction of the plate 2, and the outlet This is a point communicating with the opening 17.
  • W1 / W2 1.0
  • the air passage 13 provided in the plate 2 is provided inside the region 31 where the sensor chip 4 presses the plate 2.
  • the air passage 13 can be provided so as to avoid the high stress region directly below the sensor chip pressing region 31, and the stress generated in the air passage 13 can be reduced.
  • the air passage 13 only in the longitudinal direction of the plate 2 and communicating with the outlet opening 17, it is possible to reduce the thickness reduction region of the plate 2 due to the formation of the air passage 13. Since the bending rigidity of the plate 2 is improved as the thickness reduction region is smaller, the bending deformation of the plate 2 when the sensor assembly 10 is formed can be suppressed, and a more reliable sensor assembly 10 can be provided.

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

Abstract

La présente invention a pour but d'améliorer la précision de mesure d'un débitmètre d'air thermique. Le débitmètre d'air thermique est équipé d'un ensemble capteur comportant une structure en plomb, une plaque placée sur la structure en plomb, une puce de capteur placée sur la plaque, et une résine disposée de façon à exposer une partie diaphragme de la puce de capteur, la partie diaphragme étant disposée de façon à se trouver dans un passage secondaire. Dans le débitmètre d'air thermique, la plaque comporte une rainure ou une partie partiellement fine d'épaisseur réduite à l'extérieur d'une région de surface de support de puce de capteur au niveau de laquelle la plaque reçoit une charge de pression de la puce de capteur lors du moulage de la résine. En variante, dans un autre mode de réalisation, la surface latérale de la plaque est essentiellement au même niveau que la surface latérale de la puce de capteur au moins dans la région de support de puce de capteur.
PCT/JP2015/066423 2014-06-30 2015-06-08 Débitmètre d'air thermique WO2016002439A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2014-133497 2014-06-30
JP2014133497A JP6336833B2 (ja) 2014-06-30 2014-06-30 熱式空気流量計

Publications (1)

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WO2016002439A1 true WO2016002439A1 (fr) 2016-01-07

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WO (1) WO2016002439A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2020079711A (ja) * 2018-11-12 2020-05-28 日立オートモティブシステムズ株式会社 樹脂パッケージ並びにそれを備える流量測定装置
JP2024014020A (ja) * 2022-07-21 2024-02-01 サーパス工業株式会社 熱式流量計および熱式流量計の製造方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009036639A (ja) * 2007-08-01 2009-02-19 Denso Corp センサ装置
WO2013084259A1 (fr) * 2011-12-07 2013-06-13 日立オートモティブシステムズ株式会社 Appareil de mesure de débit d'air
JP2014010023A (ja) * 2012-06-29 2014-01-20 Hitachi Automotive Systems Ltd 熱式空気流量センサ

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009036639A (ja) * 2007-08-01 2009-02-19 Denso Corp センサ装置
WO2013084259A1 (fr) * 2011-12-07 2013-06-13 日立オートモティブシステムズ株式会社 Appareil de mesure de débit d'air
JP2014010023A (ja) * 2012-06-29 2014-01-20 Hitachi Automotive Systems Ltd 熱式空気流量センサ

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JP2016011887A (ja) 2016-01-21

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