WO2022264498A1

WO2022264498A1 - Physical quantity detection device

Info

Publication number: WO2022264498A1
Application number: PCT/JP2022/005450
Authority: WO
Inventors: 瑞紀芝田; 孝之余語; 琳琳張
Original assignee: 日立Astemo株式会社
Priority date: 2021-06-18
Filing date: 2022-02-10
Publication date: 2022-12-22
Also published as: CN117242321A; JPWO2022264498A1

Abstract

This invention provides a physical quantity detection device that is capable of suppressing positional deviation of reflow soldering between a chip package comprising a flow rate detection unit and a circuit board. This physical quantity detection device comprises a circuit board 140 and a chip package 150. The circuit board 140 comprises a plurality of lands 145 and a fixing land 146. The chip package 150 comprises a flow rate detection unit for detecting the flow rate of a gas under measurement, a plurality of outer leads 155 that protrude from both sides of the chip package 150 in the width direction Dw, and a fixing lead 156 that protrudes from the chip package 150. The distal ends of the outer leads 155 are joined via solder S to the lands 145, which are larger. The distal end of the fixing lead 156 is joined via solder S to the fixing lead 156. In the width direction Dw, the difference in length between the distal end of the fixing lead 156 and the fixing land 146 is smaller than the difference in length between the distal ends of the outer leads 155 and the lands 145.

Description

physical quantity detector

The present disclosure relates to a physical quantity detection device.

Conventionally, a thermal flow meter is known as a device for measuring the mass flow rate of the gas to be measured flowing through the main passage (see Patent Document 1 below). Patent Document 1 discloses a thermal flow meter attached to a main passage, which has a sub passage, a flow detection element, a support, and a circuit board (summary, claim Item 1).

The secondary passage takes in part of the gas to be measured flowing through the main passage. The flow rate detection element is arranged in the secondary passage. The support supports the flow rate detection element. The circuit board is fixed to the support. The flow rate detection element has a detection surface for detecting the flow rate of the gas to be measured, and the detection surface is arranged to face the circuit board.

According to this conventional thermal flow meter, the support for supporting the flow rate detection element is fixed to the circuit board, and the detection surface of the flow rate detection element is arranged to face the circuit board. A decrease in accuracy, a decrease in reliability, and an increase in cost can be reduced compared to the conventional art (Patent Document 1, paragraph 0012).

WO2019/049513

The conventional thermal flowmeter described above has a circuit package that constitutes a support that supports the flow rate detection element. The circuit package has a structure of a resin package in which a part of the flow rate detection element, a lead frame on which the flow rate detection element is mounted, a part of the input/output terminals, and circuit components are integrally sealed with a resin material. ing. The lead frame has outer leads. Outer leads protruding from the ends of the circuit package are connected and fixed to the substrate by soldering (Patent Document 1, paragraphs 0059 to 0060).

In addition, in the above conventional thermal flowmeter, the circuit package is formed with a concave groove for forming a sub-passage. The flow rate measuring part is exposed from the resin material on the bottom surface of the concave groove. The concave groove is recessed in the surface of the circuit package facing the substrate, and forms a secondary passage in cooperation with the substrate (Patent Document 1, paragraph 0063). This conventional thermal flow meter has room for improvement in suppressing misalignment between the circuit package and the substrate in reflow soldering, in which solder is melted on the substrate to join the outer leads of the circuit package to the substrate.

The present disclosure provides a physical quantity detection device capable of suppressing misalignment due to reflow soldering between a chip package including a flow rate detection unit and a circuit board.

One aspect of the present disclosure is a physical quantity detection device that detects a physical quantity of a gas to be measured flowing through a main passage, comprising: a housing installed in the main passage; a circuit board accommodated in the housing; a chip package to be mounted, wherein the housing has a circuit chamber in which the circuit board is accommodated, and a sub-passage for taking in part of the gas to be measured flowing through the main passage, the circuit board has a plurality of lands and one or a plurality of fixing lands, and the chip package includes a first resin portion arranged in the sub-passage and the sub-portion provided in the first resin portion. a flow rate detecting portion for detecting the flow rate of the gas to be measured flowing through the passage; a second resin portion provided integrally with the first resin portion and arranged in the circuit chamber; A plurality of outer leads protruding to both sides and one or a plurality of fixing leads protruding from the second resin portion are provided, and the tip portion of each outer lead of the plurality of outer leads is the tip portion. Each of the plurality of lands having a dimension in the width direction of the chip package larger than the width of the chip package is joined via solder to each of the one or more fixing leads. One or a plurality of fixing lands are joined to each fixing land via soldering, and a dimensional difference between the tip portion of each of the fixing leads and each of the fixing lands in the width direction is and the physical quantity detection device is characterized in that the dimensional difference is smaller than the dimensional difference between the tip of each outer lead and each land.

According to the above aspect of the present disclosure, it is possible to provide a physical quantity detection device capable of suppressing misalignment due to reflow soldering between a chip package including a flow rate detection unit and a circuit board.

1 is a system diagram showing an embodiment of a flow rate detection device according to the present disclosure; FIG. FIG. 2 is a front view of the physical quantity detection device of FIG. 1; FIG. 2 is a rear view of the physical quantity detection device of FIG. 1; FIG. 2 is a left side view of the physical quantity detection device of FIG. 1; FIG. 2 is a right side view of the physical quantity detection device of FIG. 1; FIG. 2 is a top view of the physical quantity detection device of FIG. 1; FIG. 3 is a front view of the physical quantity detection device of FIG. 2 with the sealing material removed; FIG. 4 is a rear view of the physical quantity detection device of FIG. 3 with the cover removed; FIG. 9 is a cross-sectional view of the physical quantity detection device taken along line IX-IX in FIG. 8; FIG. 3 is a cross-sectional view of the physical quantity detection device taken along line XX of FIG. 2; FIG. 9 is a front view of a circuit board of the physical quantity detection device of FIG. 8; Sectional drawing of the circuit board which follows the XII-XII line of FIG. FIG. 12 is an enlarged front view of the chip package mounted on the circuit board of FIG. 11; FIG. 14 is a front view of the lead frame of the chip package of FIG. 13; FIG. 14 is a schematic diagram showing the relationship between outer leads and lands of the chip package of FIG. 13; FIG. 14 is a schematic diagram showing the relationship between outer leads and lands of the chip package of FIG. 13; FIG. 17 is an enlarged front view showing Modification 1 of the embodiment of the physical quantity detection device of FIGS. 1 to 16; FIG. 17 is an enlarged front view showing Modification 2 of the embodiment of the physical quantity detection device of FIGS. 1 to 16;

An embodiment of a physical quantity detection device according to the present disclosure will be described below with reference to the drawings.

FIG. 1 is a system diagram showing one embodiment of the physical quantity detection device according to the present disclosure. The physical quantity detection device 100 of the present embodiment is used, for example, in an electronic fuel injection type internal combustion engine control system 1 . 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. there is

For example, the physical quantity detection device 100 is inserted into the interior of 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 of being 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 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 along the main flow direction of the gas 2 to be measured flowing through the main passage 22 . That is, the direction in which the physical quantity detection device 100 protrudes from the main passage 22 is, for example, the direction perpendicular to the center line 22a of the main passage 22 .

In each of the following figures, the X-axis parallel to the protruding direction of the physical quantity detection device 100 in the main passage 22 shown in FIG. A Cartesian coordinate system consisting of parallel Z-axes is shown. In the following description, it is assumed that the measured gas 2 flows along the center line 22a (Y-axis) of the main passage 22. As shown in FIG.

The throttle valve 25 is built in, for example, a throttle body 23 arranged upstream of the intake manifold 24 in the flow direction of the gas 2 to be measured. The control device 4, for example, changes the opening of the throttle valve 25 based on the operation amount of the accelerator pedal, and controls the flow rate of the intake air as the measured gas 2 flowing into the combustion chamber in the cylinder 11 of the internal combustion engine 10. do. A throttle angle sensor 26 measures the opening degree of the throttle valve 25 and outputs it to the control device 4 . The idle air control valve 27 controls the amount of air bypassing 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 taken in through an air cleaner 21 based on the movement of the piston 12 of the internal combustion engine 10 flows through the main passage 22 and the flow rate is controlled by the throttle valve 25 in the throttle body 23 . After passing through the throttle body 23 , the intake air passes through the intake manifold 24 , the fuel injection valve 14 provided in the intake port, and flows into the combustion chamber inside 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. As a result, the intake air that has passed through the intake manifold 24 is mixed with the fuel injected from the fuel injection valve 14 and led to the combustion chamber in the form of an air-fuel mixture. The control device 4 explosively combusts the air-fuel mixture in the combustion chamber by spark ignition of the spark plug 13 to cause the internal combustion engine 10 to generate mechanical energy.

The rotation angle sensor 17 detects information about the positions and states of the piston 12, the intake valve 15, and the exhaust valve 16, as well as the rotation speed of the internal combustion engine 10, and outputs the information to the control device 4. The gas generated by combustion is discharged from the combustion chamber of the cylinder 11 to the exhaust pipe through the exhaust valve 16, and is discharged as the exhaust gas 3 from the exhaust pipe to the outside of the vehicle. The oxygen sensor 28 is provided in the exhaust pipe, measures the oxygen concentration of the exhaust gas 3 flowing through the exhaust pipe, and outputs the result to the control device 4 .

The control device 4 controls each part of the internal combustion engine control system 1 based on the physical quantity of the intake air as the measured gas 2 flowing through the main passage 22 detected by the physical quantity detection device 100, for example, the flow rate, temperature, humidity, pressure, etc. to control. Specifically, when the controller 4 controls the opening of the throttle valve 25 based on the amount of operation of the accelerator pedal, 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 gas 2 to be measured detected by the physical quantity detection device 100, for example. Thereby, the mechanical energy generated by the internal combustion engine 10 is controlled.

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. do. Based on these calculation results, 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 practice, the control device 4 further determines the fuel based on the temperature of the gas 2 to be measured, the state of change in the degree of opening of the throttle valve 25, the state of change in the rotation speed of the internal combustion engine 10, and the state of the air-fuel ratio of the exhaust gas 3. It finely controls the supply amount and ignition timing. The control device 4 further controls the amount of air bypassing the throttle valve 25 when the internal combustion engine 10 is idling, using an idle air control valve 27, thereby controlling the rotation speed of the internal combustion engine 10 when the engine is idling.

The fuel supply amount and ignition timing, which are the main control amounts 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 vehicle control accuracy and ensuring reliability.

Especially in recent years, the demand for fuel efficiency of vehicles is very high, and the demand for exhaust gas purification is also very high. In order to meet these demands, it is extremely important to improve the detection accuracy of the physical quantity of intake air detected by the physical quantity detection device 100 . It is also important that the physical quantity detection device 100 maintains high reliability.

A vehicle equipped with the physical quantity detection device 100 is used in an environment with large changes in temperature and humidity. It is desirable that the physical quantity detection device 100 is also designed to deal with changes in temperature and humidity in the environment in which it is used, as well as with respect to dust and contaminants.

Also, the physical quantity detection device 100 is attached to an intake pipe that is affected by heat generated from the internal combustion engine. 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 gas 2 to be measured by conducting heat transfer with the gas 2 to be measured, it is important to suppress the influence of heat from the outside as much as possible.

The physical quantity detection device 100 of the present embodiment will be described in more detail below with reference to FIGS. 2 to 16. FIG. 2 to 6 are a front view, a rear view, a left side view, a right side view, and a top view, respectively, of the physical quantity detection device 100 of FIG. Physical quantity detection device 100 includes, for example, housing 110 and cover 120 .

The housing 110 is manufactured, for example, by injection molding a synthetic resin material. The cover 120 is, for example, a plate-like member made of metal or synthetic resin. For the cover 120, for example, a synthetic resin molded product can be used. The housing 110 and the cover 120 form a housing of the physical quantity detection device 100 arranged inside the main passage 22 . Housing 110 has, for example, flange 111 , connector 112 , and measuring section 113 .

As shown in FIG. 6, the flange 111 has a generally rectangular plate-like shape and has a pair of fixing portions 111a at diagonal corners. The fixed portion 111a has a cylindrical through-hole 111b in the central portion that penetrates the flange 111 and allows a fixing screw to pass therethrough. To fix the physical quantity detection device 100 to the main passage 22 , the measuring section 113 is inserted into the mounting hole provided in the main passage 22 . Then, the fixing screw inserted through the through hole 111 b of the flange 111 is screwed into the screw hole of the main passage 22 to fix the flange 111 to the passage wall of the main passage 22 . As a result, the physical quantity detection device 100 is fixed to the main passage 22 , which is the intake body, and the housing 110 is set to the main passage 22 .

The connector 112 protrudes from the flange 111, is arranged outside the main passage 22, which is the intake body, and is connected to an external device. As shown in FIG. 5, inside the connector 112, a plurality of external terminals 112a and correction terminals 112b are provided. External terminals 112 a include, for example, output terminals for physical quantities such as flow rate and temperature, which are measurement results of physical quantity detection device 100 , and power terminals for supplying DC power for operating 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, obtain the correction value for each physical quantity detection device 100, and store the correction value in the internal memory of the physical quantity detection device 100. In subsequent physical quantity measurement by the physical quantity detection device 100, the correction data based on the correction value stored in the memory is used, and the correction terminal 112b is not used.

The measuring portion 113 extends from a 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 orthogonal to the center line 22a. The measurement unit 113 has a generally rectangular parallelepiped flat square shape. The measuring part 113 has a length in the projecting direction (X-axis direction) of the measuring part 113 in the main passage 22, and a width in the main flow direction (Y-axis direction) of the gas 2 to be measured in the main passage 22. there is Moreover, the measuring part 113 has a thickness in the projecting direction (X-axis direction) and in the direction (Z-axis direction) orthogonal to the main flow direction (Y-axis direction) of the gas 2 to be measured. In this way, the measuring part 113 has a flat shape along the main flow direction of the gas 2 to be measured, so that the fluid resistance to the gas 2 to be measured can be reduced.

The measurement unit 113 has a front surface 113a, a rear surface 113b, an upstream side surface 113c, a downstream side surface 113d, and a lower surface 113e. The front surface 113a and the rear surface 113b are larger in area than the other surfaces of the measurement unit 113, and are generally parallel to the projecting direction of the measurement unit 113 (X-axis direction) and the center line 22a of the main passage 22 (Y-axis direction). The side surface 113c on the upstream side and the side surface 113d on the downstream side have an elongated shape with an area smaller than that of the front surface 113a and the rear surface 113b, and are substantially perpendicular to the center line 22a (Y-axis direction) of the main passage 22. As shown in FIG. The lower surface 113e has a smaller area than the other surfaces of the measuring section 113, is generally parallel to the center line 22a (Y-axis direction) of the main passage 22, and is generally orthogonal to the projecting direction (X-axis direction) of the measuring section 113. .

The measurement unit 113 has a sub-passage entrance 114 on the upstream side surface 113c, and has a first outlet 115 and a second outlet 116 on the downstream side surface 113d. The auxiliary passage inlet 114, the first outlet 115, and the second outlet 116 are provided at the tip of the measuring section 113 on the tip side of the center of the measuring section 113 in the projecting direction (X-axis direction). As a result, the gas to be measured 2 near the central portion of the main passage 22 away from the inner wall surface of the main passage 22 can be taken in from the sub-passage inlet 114 . Therefore, the physical quantity detection device 100 can suppress deterioration in measurement accuracy due to the heat of the internal combustion engine 10 .

FIG. 7 is a front view of the physical quantity detection device 100 of FIG. 2 before the sealing material 119 is arranged. FIG. 8 is a rear view of the physical quantity detection device 100 of FIG. 1 before the cover 120 is attached. FIG. 9 is a cross-sectional view of physical quantity detection device 100 taken along line IX-IX in FIG. FIG. 10 is a cross-sectional view of physical quantity detection device 100 taken along line XX of FIG.

The external terminals 112a of the connector 112 shown in FIG. 5 are connected to pads of the circuit board 140 via bonding wires 143, for example, as shown in FIG. Circuit board 140 has, for example, protection circuit 144 mounted on the surface to which bonding wires 143 are connected, and housed in housing 110 . Protection circuit 144 stabilizes the voltage in the circuit and removes noise. These bonding wires 143 and protection circuit 144 are covered and sealed with a sealing material 119, as shown in FIG. As the sealing material 119, for example, a silicone gel or an epoxy-based sealing material having higher rigidity than a silicone-based sealing material can be used.

As shown in FIG. 8, the housing 110 has a recessed secondary passage groove 117 and a recessed circuit chamber 118 on the side of the back surface 113b of the measuring section 113. As shown in FIG. Circuit chamber 118 accommodates circuit board 140 . As shown in FIG. 10 , the sub-passage groove 117 forms a sub-passage 130 together with the cover 120 by closing the opening with the cover 120 . The secondary passage 130 takes in a part of the gas 2 to be measured flowing through the main passage 22 and makes a detour. A part of the gas 2 to be measured flowing through the main passage 22 is taken into the sub passage 130 from the sub passage inlet 114 opening on the upstream side surface 113c of the measuring section 113, for example, as shown in FIG.

The sub-passage groove 117 has, for example, a first sub-passage groove 117a and a second sub-passage groove 117b. As shown in FIG. 8, the first sub-passage groove 117a extends from the sub-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. , along the center line 22 a (Y-axis direction) of the main passage 22 . First sub-passage groove 117a forms first sub-passage 131 with cover 120, for example, as shown in FIG. The first sub-passage 131 returns the measured gas 2 taken in from the sub-passage inlet 114 to the main passage 22 through the first outlet 115 .

As shown in FIG. 8, the second sub-passage groove 117b branches from the middle of the first sub-passage groove 117a and extends toward the flange 111 along the projecting direction (X-axis direction) of the measuring portion 113. . Further, the second sub-passage groove 117b curves in a U-shape so as to be folded back in the opposite direction and extends toward the tip portion of the measuring portion 113 along the projecting direction (X-axis direction) of the measuring portion 113 . The second sub-passage groove 117b is curved in the direction along the center line 22a (Y-axis direction) of the main passage 22 at the tip of the measuring portion 113, and is a second outlet that opens on the side surface 113d on the downstream side of the measuring portion 113. 116. For example, as shown in FIG. 9 , second subpassage groove 117 b forms second subpassage 132 with cover 120 by closing the opening with cover 120 . Sub-passage 130 includes a first sub-passage 131 and a second sub-passage 132 .

The circuit chamber 118 is provided in a concave shape on the base end side of the measuring section 113 connected to the flange 111 on the rear surface 113b side of the measuring section 113 of the housing 110 and accommodates the circuit board 140 . The circuit chamber 118 is located on the base end side of the measuring section 113 relative to the first sub-passage groove 117a of the sub-passage groove 117, and is the second sub-passage in the main flow direction (Y-axis direction) of the gas to be measured 2 flowing through the main passage 22. It is provided adjacent to the upstream side of the groove 117b.

11 is a front view of the circuit board 140 of the physical quantity detection device 100 shown in FIG. FIG. 12 is a cross-sectional view of circuit board 140 taken along line XII-XII in FIG. 13 is an enlarged front view of the chip package 150 mounted on the circuit board 140 of FIG. 11. FIG. 14 is a front view of the lead frame 153 of the chip package 150 shown in FIG. 13. FIG.

The chip package 150 is mounted on the surface of the circuit board 140 . The chip package 150 has a first resin portion 150a and a second resin portion 150b. The first resin portion 150a and the second resin portion 150b are, for example, resin sealing portions integrally formed by transfer molding of thermosetting resin. As shown in FIGS. 8 and 9, the first resin portion 150a is arranged in the sub passage 130 of the housing 110, and the second resin portion 150b is arranged in the circuit chamber 118 of the housing 110. As shown in FIGS.

Here, the width direction Dw of the chip package 150 is, for example, parallel to the projection direction (X-axis direction) of the physical quantity detection device 100, as shown in FIG. Also, the longitudinal direction Dl of the chip package 150 orthogonal to the width direction Dw of the chip package 150 is parallel to the width direction (Y-axis direction) of the measuring section 113, that is, the center line 22a of the main passage 22, for example.

The chip package 150 has a flow rate detector 151, as shown in FIGS. The flow rate detecting portion 151 is provided in the first resin portion 150 a and detects the flow rate of the gas to be measured 2 flowing through the secondary passage 130 . The flow detection unit 151 is, for example, a thermal flow sensor, and as shown in FIG. 12, includes a semiconductor substrate 151a, a diaphragm 151d formed on the surface side of the semiconductor substrate 151a and exposed from the first resin portion 150a, have.

Although not shown, the diaphragm 151d includes, for example, a pair of temperature sensors arranged upstream and downstream in the flow direction of the gas 2 to be measured, and a heater arranged between the pair of temperature sensors. there is The flow rate detection unit 151 measures the flow rate of the gas 2 to be measured by, for example, detecting a temperature difference with a pair of temperature sensors of the diaphragm 151d.

For example, as shown in FIG. 12, the flow rate detection unit 151 measures the flow rate of the gas to be measured 2 flowing through the measurement channel 132a formed between the circuit board 140 and the concave groove 150c of the chip package 150. Measurement flow path 132a is formed, for example, in second sub-passage groove 117b of sub-passage groove 117, that is, second sub-passage 132 of sub-passage 130, as shown in FIGS.

The chip package 150 has an electronic component 152 and a lead frame 153, for example. Electronic component 152 is mounted on lead frame 153 together with flow rate detector 151 . The electronic component 152 is, for example, an LSI, is connected to the flow rate detection section 151 via a bonding wire, and drives the flow rate detection section 151 .

The lead frame 153 has, for example, a die pad 154, a plurality of outer leads 155, and a pair of fixing leads 156, as shown in FIG. Note that the lead frame 153 may have one or three or more fixing leads 156 . The die pad 154, for example, has the flow rate detection unit 151 and the electronic component 152 mounted thereon, is sealed with the first resin portion 150a and the second resin portion 150b, and is embedded in the first resin portion 150a and the second resin portion 150b. .

A plurality of outer leads 155 are connected, for example, to the die pad 154 via bonding wires (not shown), and connected to the flow rate detector 151 or the electronic component 152 . The plurality of outer leads 155 protrude from the second resin portion 150b of the chip package 150 to both sides in the width direction Dw of the chip package 150, as shown in FIG.

One or more fixing leads 156 are directly connected to the die pad 154 without bonding wires, for example. Specifically, in the example shown in FIG. 14, a pair of fixing leads 156 are directly connected to the die pad 154 . 13, the pair of fixing leads 156 are arranged on both sides of the second resin portion 150b in the width direction Dw at positions closer to the first resin portion 150a than the plurality of outer leads 155. ing.

Also, the pair of fixing leads 156 protrude from the second resin portion 150b of the chip package 150 in the width direction Dw, similarly to the outer leads 155 . The direction in which one or more fixing leads 156 protrude from the second resin portion 150b is arbitrary, and is not limited to the width direction Dw.

The circuit board 140 has, for example, multiple lands 145 and one or multiple fixing lands 146 . In the example shown in FIG. 13, circuit board 140 has a pair of fixing lands 146 . Each land 145 is connected to, for example, wiring that constitutes the circuit of the circuit board 140 . On the other hand, the fixing land 146 is not connected to the circuit of the circuit board 140, or is connected to the ground wiring, for example.

The plurality of lands 145 are arranged, for example, on both sides of the second resin portion 150b in the width direction Dw of the chip package 150, and arranged at equal intervals in the longitudinal direction Dl of the chip package 150. The pair of fixing lands 146 are arranged on both sides of the chip package 150 in the width direction Dw at positions closer to the first resin portion 150 a than the plurality of lands 145 . The circuit board 140 may have only one fixing land 146 or may have three or more fixing lands 146 .

For example, as shown in FIG. 13, each land 145 has the same shape and size. It has a rectangular shape with the longitudinal direction Dl of 150 as the lateral direction. Each fixing land 146 has a rectangular shape like each land 145 , but the dimension in the width direction Dw of the chip package 150 is smaller than that of the land 145 .

In the example shown in FIG. 13, each land 145 and each fixing land 146 have approximately the same dimension in the longitudinal direction Dl of the chip package 150. In the example shown in FIG. However, the dimension of each fixing land 146 may be smaller than the dimension of each land 145 in the longitudinal direction Dl of the chip package 150 .

The tip of each outer lead 155 of the plurality of outer leads 155 of the chip package 150 is joined to each of the plurality of lands 145 with solder S. One or a plurality of fixing lands 146, specifically, a tip of each fixing land 146 of a pair of fixing lands 146 is connected to one or a plurality of fixing leads 156, specifically a pair of fixing lands 146. It is joined to each fixing lead 156 via solder S. As shown in FIG.

Solder S is formed, for example, by a reflow method in which solder paste is printed on lands 145 and fixing lands 146, and tips of outer leads 155 and fixing leads 156 of chip package 150 are placed thereon and heated. It is reflow solder. In the physical quantity detection device 100 of this embodiment, the dimensional difference between the tip of each fixing lead 156 and each fixing land 146 in the width direction Dw of the chip package 150 is equal to that of the tip of each outer lead 155. It is smaller than the dimensional difference with each land 145 .

15 and 16 are a schematic front view and a cross-sectional view, respectively, showing the relationship between the tip of the outer lead 155 and the land 145 of the chip package 150 of FIG. 15, illustration of the solder S is omitted. Here, dimension a is the width of land 145 or fixing land 146 in longitudinal direction Dl of chip package 150 . A dimension L1 is a length in the width direction Dw of the chip package 150 of the land 145 or the tip of the outer lead 155 or the fixing lead 156 reflow-soldered to the land 145 . A dimension L2 is the width of the tip of the outer lead 155 or the fixing lead 156 in the longitudinal direction Dl of the chip package 150 .

The surface of the circuit board 140 is covered with a solder resist SR except for a part. The solder resist SR has openings SRo at positions corresponding to the lands 145 . A dimension r1 is a distance between one end of the opening SRo of the solder resist SR and one end of the land 145 and the fixing land 146 in the width direction Dw of the chip package 150 . A dimension r2 is the length of the portion of the other end of the land 145 and the fixing land 146 covered with the solder resist SR in the width direction Dw of the chip package 150 .

Also, the dimension α1 is the distance from the edge covered with the solder resist SR outside the land 145 or the fixing land 146 to the tip of the outer lead 155 or the fixing lead 156 in the width direction Dw of the chip package 150 . be. Dimension α2 is the distance from the inner edge of land 145 or fixing land 146 to the tip of outer lead 155 or fixing lead 156 in width direction Dw of chip package 150 .

In this case, in the width direction Dw of the chip package 150, the length of the non-overlapping portion between the exposed portion of the land 145 exposed from the opening SRo of the solder resist SR and the tip portion of the outer lead 155 is (α1−r2+α2). . In addition, the exposed portion of land 145 and the tip of outer lead 155 satisfy the relationship of (α1−r2+α2)/L1≧2 in width direction Dw of chip package 150, for example. That is, in the width direction Dw of the chip package 150, the length (α1−r2+α2) of the non-overlapping portion between the exposed portion of the land 145 and the tip of the outer lead 155 is, for example, the length L1 of the tip of the outer lead 155. is more than twice as large as

On the other hand, in the width direction Dw of the chip package 150, the exposed portions of the fixing lands 146 exposed from the openings SRo of the solder resist SR and the tip portions of the fixing leads 156 are arranged in the width direction Dw of the chip package 150 as follows, for example: It satisfies the relationship (α1−r2+α2)/L1<2. That is, in the width direction Dw of the chip package 150, the length (α1−r2+α2) of the non-overlapping portion between the exposed portion of the fixing land 146 and the tip of the fixing lead 156 is, for example, the tip of the fixing lead 156. is less than twice the length L1 of .

In addition, in the longitudinal direction Dl of the chip package 150, the land 145 and the tip of the outer lead 155 satisfy the relationship a/L2≧1, for example. That is, the width a of the land 145 is equal to or greater than the width L2 of the outer lead 155 in the longitudinal direction Dl of the chip package 150 . On the other hand, in the longitudinal direction Dl of the chip package 150, the fixing land 146 and the tip portion of the fixing lead 156 satisfy the relationship a/L2≧1 or a/L2<1, for example. That is, in the longitudinal direction Dl of the chip package 150, the width a of the fixing land 146 may be equal to or greater than the width L2 of the outer lead 155, but may be smaller than the width L2 of the outer lead 155.

In addition, the dimension (α1−r2+α2) of the non-overlapping portion between the land 145 and the tip of the outer lead 155 in the width direction Dw of the chip package 150 is the tip of the land 145 and the tip of the outer lead 155 in the longitudinal direction Dl of the chip package 150. is larger than the dimension (a−L2) of the non-overlapping portion with In addition, in the longitudinal direction Dl of the chip package 150, the dimension (a−L2) of the non-overlapping portion between the fixing land 146 and the fixing lead 156 is the dimension of the non-overlapping portion between the land 145 and the tip of the outer lead 155. It may be smaller than (a−L2). Also, in the longitudinal direction Dl of the chip package 150, the dimension a of the fixing land 146 may be larger than the dimension L2 of the fixing lead 156, but may be less than or equal to the dimension L2 of the fixing lead 156.

In addition to the chip package 150 having the flow rate detection unit 151, at least one of a temperature sensor 160, a pressure sensor 170, and a humidity sensor 180 is mounted on the circuit board 140, as shown in FIG. . These flow rate sensor, temperature sensor 160 , pressure sensor 170 , and humidity sensor 180 are sensor units that detect the physical quantity of the gas 2 to be measured taken into the secondary passage 130 of the physical quantity detection device 100 .

The sensor section of the physical quantity detection device 100 including the chip package 150, the temperature sensor 160, the pressure sensor 170, and the humidity sensor 180 is attached to the surface of the circuit board 140 and mounted on the circuit board 140. It should be noted that the circuit board 140 does not need to include all of the temperature sensor 160, the pressure sensor 170, and the humidity sensor 180 in addition to the flow rate detection unit 151, and any one of the sensor units may be omitted. It is possible.

The temperature sensor 160 is, for example, a chip-type temperature sensor mounted on the circuit board 140 . For example, as shown in FIG. 8, temperature sensor 160 is arranged at the tip of extension portion 140c of circuit board 140 that extends toward the tip of measurement portion 113 in the projecting direction (X-axis direction) of measurement portion 113. there is The temperature sensor 160 is arranged in the temperature measurement passage 190 of the measurement section 113 shown in FIG.

As shown in FIG. 4, the temperature measurement passage 190 has an entrance on the side surface 113c on the upstream side of the measurement section 113, and as shown in FIGS. have an exit. The temperature measurement passage 190 takes in the gas to be measured 2 flowing through the main passage 22 from an inlet opening on the upstream side surface 113c of the measuring unit 113, and passes through an outlet opening on the front surface 113a and the rear surface 113b of the measuring unit 113. 22. Such a configuration can improve the heat dissipation of the temperature sensor 160 .

For example, as shown in FIG. 8, the pressure sensor 170 is mounted on the surface of the circuit board 140 and arranged inside the circuit chamber 118 . The circuit chamber 118 communicates with the folded portion of the second sub-passage groove 117 b that curves in a U shape near the flange 111 , that is, the folded portion of the second sub-passage 132 . This makes it possible to measure the pressure of the gas 2 to be measured taken into the secondary passage 130 by the pressure sensor 170 arranged in the circuit chamber 118 .

For example, the humidity sensor 180 is mounted on the surface of the circuit board 140 as shown in FIG. This partitioned area communicates with, for example, the second sub-passage 132 of the sub-passage 130 . Thereby, the humidity sensor 180 detects the humidity of the gas 2 to be measured taken into the secondary passage 130 .

The operation of the physical quantity detection device 100 of this embodiment will be described below.

The physical quantity detection device 100 of this embodiment detects the physical quantity of the measured gas 2 flowing through the main passage 22 as described above. The physical quantity detection device 100 includes a housing 110 installed in the main passage 22 , a circuit board 140 accommodated in the housing 110 , and a chip package 150 mounted on the circuit board 140 . The housing 110 has a circuit chamber 118 in which a circuit board 140 is accommodated, and a secondary passage 130 that takes in part of the gas 2 to be measured flowing through the main passage 22 . The circuit board 140 has multiple lands 145 and one or multiple fixing lands 146 . The chip package 150 includes a first resin portion 150a arranged in the sub-passage 130, a flow rate detection portion 151 provided in the first resin portion 150a for detecting the flow rate of the gas 2 to be measured flowing through the sub-passage 130, A second resin portion 150b provided integrally with the first resin portion 150a and arranged in the circuit chamber 118, a plurality of outer leads 155 projecting from the second resin portion 150b to both sides in the width direction Dw, and the second resin portion. and one or more fixation leads 156 protruding from 150b. The tip of each outer lead 155 of the plurality of outer leads 155 is joined via solder S to each of the lands 145 having a larger dimension in the width direction Dw of the chip package 150 than the tip of the outer lead 155 . ing. The tip of each of the one or more fixing leads 156 is joined via solder S to each of the one or more fixing lands 146 . In the width direction Dw of the chip package 150, the dimensional difference between the tip of each fixing lead 156 and each fixing land 146 is the dimensional difference between the tip of each outer lead 155 and each land 145. less than

The physical quantity detection device 100 having such a configuration is manufactured by reflow soldering the plurality of outer leads 155 of the chip package 150 to the plurality of lands 145 of the circuit board 140, and mounting the chip package 150 on the circuit board 140. be. At this time, one or more fixing leads 156 are also reflow soldered to one or more fixing lands 146 . In reflow soldering, a solder paste containing solder particles and cream flux is placed on the land 145 and the fixing land 146 by printing or the like. Furthermore, when the solder paste is heated and the solder melts and flows on the land 145 , the tip of the outer lead 155 tries to move on the land 145 . Since the chip package 150 has the outer leads 155 in the second resin portion 150b instead of the first resin portion 150a in which the flow rate detection portion 151 is provided, the positional deviation due to the rotational moment increases. On the other hand, the dimensional difference between the tip of each fixing lead 156 and each fixing land 146 is smaller than the dimensional difference between the tip of each outer lead 155 and each land 145 .

Therefore, the relative movement between the tip of each fixing lead 156 and each fixing land 146 is smaller than the relative movement between the tip of each outer lead 155 and each land 145 . As a result, relative movement between the tip of each outer lead 155 and each land 145 is restrained, and displacement of the chip package 150 with respect to the circuit board 140, including displacement caused by rotational moment acting on the chip package 150, is prevented. is prevented. As a result, the mounting position accuracy of the chip package 150 with respect to the circuit board 140 is improved, and the first resin portion 150a can be arranged at a predetermined position within the sub-passage 130 . Thereby, the formation accuracy of the measurement flow path 132a formed between the first resin portion 150a and the circuit board 140 within the sub-passage 130 is improved. Therefore, according to the physical quantity detection device 100 of the present embodiment, in addition to improving the reliability by improving the fillet formation of the solder S that joins the outer lead 155 to the land 145, the flow rate of the gas to be measured 2 flowing through the measurement channel 132a is detected. It is possible to improve the detection characteristics of the flow rate detection unit 151 that does so.

In addition, in the physical quantity detection device 100 of the present embodiment, the chip package 150 has a die pad 154 on which the flow rate detection section 151 is mounted and which is embedded in the first resin section 150a and the second resin section 150b. A plurality of outer leads 155 are connected to the die pad 154 via bonding wires, and one or more fixing leads 156 are directly connected to the die pad 154 .

With such a configuration, the physical quantity detection device 100 of this embodiment can prevent the die pad 154 from being misaligned with respect to the circuit board 140 by the fixing lead 156 directly connected to the die pad 154 . As a result, the mounting position accuracy of the flow rate detection unit 151 mounted on the die pad 154 on the circuit board 140 can be improved, and variations in the detection characteristics of the flow rate detection unit 151 can be suppressed.

Further, in the physical quantity detection device 100 of this embodiment, the one or more fixing lands 146 are a pair of fixing lands 146, and the one or more fixing leads 156 are a pair of fixing leads. . The pair of fixing lands 146 and the pair of fixing leads 156 are closer to the first resin portion 150a than the plurality of lands 145 and the plurality of outer leads 155 on both sides of the second resin portion 150b in the width direction Dw of the chip package 150. placed in position.

With such a configuration, the physical quantity detection device 100 of the present embodiment attaches the chip package 150 to the first resin portion 150a by the pair of fixing leads 156 projecting from the second resin portion 150b in the width direction Dw of the chip package 150. can be constrained to the circuit board 140 at a position closer to the As a result, it is possible to more effectively suppress misalignment with respect to the circuit board 140 due to the rotational moment acting on the chip package 150 during reflow soldering.

As described above, according to the present embodiment, it is possible to provide the physical quantity detection device 100 capable of suppressing positional deviation due to reflow soldering between the chip package 150 including the flow rate detection unit 151 and the circuit board 140. can. Note that the physical quantity detection device according to the present disclosure is not limited to the configuration of the physical quantity detection device 100 of this embodiment. For example, the physical quantity detection device 100 may have one fixing lead 156 between multiple outer leads 155 . Several modifications of the physical quantity detection device 100 of this embodiment will be described below.

FIG. 17 is an enlarged front view corresponding to FIG. 13 showing Modification 1 of the physical quantity detection device 100 of the above embodiment. In the physical quantity detection device 100 of Modification 1, one or a plurality of fixing lands 146 and one or a plurality of fixing leads 156 are provided on both sides of the second resin portion 150b in the width direction Dw. They are a fixing land 146 and a pair of fixing leads 156 . Of the pair of fixing lands 146 and the pair of fixing leads 156, one fixing land 146 and one fixing lead 156 are located on one side of the second resin portion 150b in the width direction Dw and are aligned with the plurality of lands 145. The other fixing land 146 and the other fixing lead 156 are provided at positions closer to the first resin portion 150a than the plurality of outer leads 155, and the other fixing land 146 and the other fixing lead 156 are provided on the other side of the second resin portion 150b in the width direction Dw. It is arranged at a position farther from the first resin portion 150 a than the land 145 and the plurality of outer leads 155 . The physical quantity detection device 100 of this modified example can also achieve the same effect as the physical quantity detection device 100 of the above-described embodiment.

FIG. 18 is an enlarged front view corresponding to FIG. 13 showing modification 2 of the physical quantity detection device 100 described above. In the physical quantity detection device 100 of Modification 2, the one or more fixation leads 156 are one fixation lead 156 . The one fixing lead 156 is provided at the end of the second resin portion 150b opposite to the first resin portion 150a in the longitudinal direction Dl orthogonal to the width direction Dw of the chip package 150, It protrudes in the direction opposite to the first resin portion 150a from the central portion in the direction Dw. The physical quantity detection device 100 of this modified example can also achieve the same effect as the physical quantity detection device 100 of the above-described embodiment.

The embodiments and modifications thereof of the physical quantity detection device according to the present disclosure have been described in detail above with reference to the drawings, but the specific configuration is not limited to this embodiment and does not depart from the gist of the present disclosure. Even if there are design changes etc. within the scope, they are included in the present disclosure.

2 gas to be measured 22 main passage 100 physical quantity detection device 110 housing 118 circuit chamber 130 sub passage 140 circuit board 145 land 146 fixing land 150 chip package 150a first resin portion 150b second resin portion 151 flow rate detection portion 154 die pad 155 outer lead 156 Fixing lead Dw Width direction S Solder

Claims

A physical quantity detection device for detecting a physical quantity of a gas to be measured flowing through a main passage,
a housing installed in the main passage, a circuit board accommodated in the housing, and a chip package mounted on the circuit board,
The housing has a circuit chamber in which the circuit board is accommodated, and a secondary passage that takes in part of the gas to be measured flowing through the main passage,
The circuit board has a plurality of lands and one or more fixing lands,
The chip package includes: a first resin portion arranged in the sub-passage; a flow rate detecting portion provided in the first resin portion for detecting a flow rate of the gas to be measured flowing through the sub-passage; a second resin portion provided integrally with a portion and arranged in the circuit chamber; a plurality of outer leads projecting from the second resin portion to both sides in the width direction; a plurality of fixation leads;
a tip of each of the plurality of outer leads is joined via solder to each of the plurality of lands having a larger dimension in the width direction of the chip package than the tip of the outer lead,
a tip of each of the one or more fixing leads is joined to each of the one or more fixing lands via solder,
In the width direction, the dimensional difference between the tip portion of each fixing lead and each fixing land is smaller than the dimensional difference between the tip portion of each outer lead and each land. A physical quantity detection device characterized by:
The chip package has a die pad on which the flow rate detection unit is mounted and which is embedded in the first resin portion and the second resin portion,
2. The method according to claim 1, wherein said plurality of outer leads are connected to said die pad via bonding wires, and said one or more fixing leads are directly connected to said die pad. Physical quantity detection device.
The one or more fixing lands are a pair of fixing lands,
The one or more fixation leads are a pair of fixation leads,
The pair of fixing lands and the pair of fixing leads are arranged on both sides of the second resin portion in the width direction at positions closer to the first resin portion than the plurality of lands and the plurality of outer leads. 2. The physical quantity detection device according to claim 1, wherein the physical quantity detection device comprises:
The one or more fixing lands and the one or more fixing leads are a pair of fixing lands and a pair of fixing leads respectively provided on both sides of the second resin portion in the width direction. ,
Of the pair of fixing lands and the pair of fixing leads, one fixing land and one fixing lead are located on one side of the second resin portion in the width direction. The other fixing land and the other fixing lead are provided at a position closer to the first resin portion than the outer lead of the second resin portion, and the other fixing land and the other fixing lead are arranged on the other side of the second resin portion in the width direction so that the plurality of lands and the 2. The physical quantity detection device according to claim 1, wherein the physical quantity detection device is arranged at a position farther from the first resin portion than the plurality of outer leads.
the one or more fixation leads is one fixation lead,
The one fixing lead is provided at an end portion of the second resin portion opposite to the first resin portion in a longitudinal direction perpendicular to the width direction of the chip package, and is provided at the end portion in the width direction. 2. The physical quantity detection device according to claim 1, wherein the physical quantity detection device projects from the central portion of the first resin portion in a direction opposite to the first resin portion.