JPH1068645A - Sensor mounting plate, sensor unit and flow sensor module - Google Patents

Abstract

(57) [Problem] To accurately measure a flow velocity using a sensor chip having a large number of output terminals. SOLUTION: A sensor mounting plate 11 of a sensor unit 10 is provided.
The lead pins are attached to the lead pin connection lands in a state where they are electrically connected to each other. The mounting recess 23 of the sensor holding member engages with the sensor mounting plate 11 while the lead pins are passed through the lead pin through holes 24. And holds the sensor unit 10 in a predetermined direction.
Since the airtightness between the sensor unit and the sensor holding member is ensured, accurate measurement can be performed without leakage of the fluid, and the restriction for the installation of the lead pin is relaxed. Various measurements using a sensor body having an output terminal are possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor mounting plate, a sensor unit and a flow sensor module, and more particularly to a sensor mounting plate for a sensor having a directional mounting such as a heat propagation time measuring type flow sensor. The present invention relates to a sensor unit and a flow rate sensor module.

[0002]

2. Description of the Related Art FIG. 6 shows a conventional heat propagation time measuring type flow velocity sensor (hereinafter referred to as a flow velocity sensor). Here, FIG.
FIG. 6A is a top view in a state where a sensor chip is die-bonded to a sensor package, and FIG. 6B is a cross-sectional view of the sensor package.

The sensor package 40 is provided with a substantially cylindrical Ni-plated metal casing 41 having a flange portion 41a and a filling state inside the casing 41, and a lead pin 43 is attached to the casing 41 with respect to the casing 41. A glass member 42 which is held in an inserted state such that one end 43a of the lead pin 43 projects toward the mounting surface on which the sensor chip 50 is mounted while ensuring an insulated state and an airtight state. I have.

In this case, the lead pin 43 has
In order to maintain the electrical connection state well over a long period of time, Ni plating and Au plating are applied. FIG. 7 shows a partially enlarged view of the sensor chip 50 shown in FIG. 6A and its vicinity. In this case, the sensor chip 50 is die-bonded to the sensor package and wire-bonded.

The sensor chip 50 includes a micro heater (not shown) for generating heat for measuring the heat propagation time, and a thermopile (not shown) for measuring the heat generated by the micro heater and transmitted by the gas to be measured for the flow velocity. , Is configured.

[0006] One of a set of wires drawn from the microheater is connected to a microheater electrode pad 51a, and the other is a common electrode pad (ground) 51b.
It is connected to the. One of a set of wirings drawn out of the thermopile is a thermopile electrode pad 51d.
And the other is connected to the common electrode pad 51c.

Further, a micro heater electrode pad 51a is provided.
Are electrically connected to the micro heater lead pin 43a of the lead pins 43 by an Au wire (for example, φ25 μm) 52a, and the common electrode pad 51b and the common electrode pad 51c are connected to the common electrode lead pin 43b of the lead pin 43. The Au wire 52b and the Au wire 52c are electrically connected, and the thermopile electrode pad 51d is electrically connected to the thermopile lead pin 43c of the lead pins 43 by the Au wire 52d.

As described above, each electrode pad (ie, output terminal) 51 of the sensor chip 50 and the lead pin 43 are connected by the Au wire 52 as a bonding wire.

[0009]

In the above-mentioned conventional flow velocity sensor, the lead pin 43 is disposed in the flow path of the fluid (gas) to be measured.
3 so that the flow path of the gas to be measured is not disturbed by the lead pin 43 shown in FIG.
Must be disposed downstream of the sensor chip 50 in the gas flow path with respect to the gas flow direction indicated by the arrow.

Therefore, there is a problem that the position where the lead pin 43 is provided is restricted. Furthermore, when the flow path of the fluid to be measured is narrow (for example, a width of 2.5 [m
m]), in the flow rate sensor having the above structure, a large number (four or more) of lead pins are provided due to restrictions imposed by the hermetic structure, restrictions on the diameter of the lead pins caused by the strength of each lead pin 43, and the like. There is a problem that a flow rate sensor cannot be configured.

An object of the present invention is to provide a sensor mounting plate, a sensor unit, and a flow rate sensor module which can use a sensor chip having a large number of output terminals.

[0012]

According to a first aspect of the present invention, there is provided a sensor body having a predetermined mounting direction with respect to a flow path forming member for forming a flow path of a fluid to be measured. A sensor mounting plate used for a flow rate sensor module having a sensor output signal from the sensor main body as flow rate information of the measurement target fluid, wherein a plate-shaped insulating substrate and a part of the flow path are formed. A sensor mounting land portion provided on one surface of the insulating substrate, for mounting the sensor body, and a pad portion provided on the one surface and electrically connected to an output terminal of the sensor body, The pad is provided on the other surface of the insulating substrate, and is provided with a lead pin connection land portion electrically connected to the pad portion via the inside of the insulating substrate.

According to the first aspect of the present invention, one surface of the plate-like insulating substrate forms a part of the flow path, and the output terminal of the sensor body attached to the sensor mounting land is a pad portion. Is electrically connected to Further, the pad portion is electrically connected to a lead pin connection land provided on the other surface of the insulating substrate via the inside of the insulating substrate, and further electrically connected to a lead pin connected to the lead pin connection land. Then, a sensor output signal is output to the outside.

According to a second aspect of the present invention, in the first aspect of the present invention, the insulating substrate is formed of a ceramic material, and the sensor mounting lands, pad portions, and lead pin connecting lands are formed of a conductive material. Is formed by printing. According to the second aspect of the invention, in addition to the function of the first aspect, the insulating substrate is formed of a ceramic material, and the sensor mounting land, the pad, and the lead pin connection land are electrically conductive. It is formed by printing a material.

According to a third aspect of the present invention, there is provided a sensor unit having the sensor mounting plate according to the first or second aspect, wherein the sensor body is mounted on a bare chip in the mounting direction. According to a third aspect of the present invention, a sensor unit has the sensor mounting plate according to the first or second aspect, and the sensor body is mounted on a bare chip in a mounting direction.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the output terminal of the sensor body and the pad portion are connected by a bonding wire. According to the fourth aspect of the invention, in addition to the function of the third aspect, the output terminal of the sensor body and the pad portion are connected by a bonding wire.

According to a fifth aspect of the present invention, in the third aspect, the output terminal of the sensor main body and the pad portion are connected by a flip chip. According to the fifth aspect of the invention, in addition to the function of the third aspect of the invention, the output terminal of the sensor main body and the pad portion are connected by a flip chip.

According to a sixth aspect of the present invention, the sensor unit is attached to the sensor unit according to any one of the third to fifth aspects in a state where the sensor unit is electrically connected to the lead pin connecting lands of the sensor mounting plate. A sensor holding member having a lead pin, a mounting recess engaged with the sensor mounting plate and holding the sensor unit in a predetermined direction, and a lead pin through hole for passing the lead pin, the sensor unit and the sensor And a sealing portion for ensuring airtightness with the holding member.

According to a sixth aspect of the present invention, the lead pin is electrically connected to the lead pin connecting land of the sensor mounting plate of the sensor unit according to any one of the third to fifth aspects. The mounting recess of the sensor holding member is engaged with the sensor mounting plate in a state where the lead pin is passed through the lead pin through hole, and holds the sensor unit in a predetermined direction.

Further, the sealing portion ensures airtightness between the sensor unit and the sensor holding member. According to a seventh aspect of the present invention, in the sixth aspect of the present invention, a flow path sealing portion for ensuring airtightness between the flow path forming member and the sensor holding member is provided.

According to the seventh aspect of the invention, in addition to the function of the sixth aspect, the flow path sealing portion ensures airtightness between the flow path forming member and the sensor holding member. The invention according to claim 8 is the invention according to claim 6 or 7, further comprising a through hole sealing portion for ensuring the airtightness of the lead pin through hole.

According to the eighth aspect of the invention, in addition to the function of the sixth or seventh aspect, the through hole sealing portion ensures the airtightness of the through hole for the lead pin.

[0023]

Preferred embodiments of the present invention will now be described with reference to the drawings. FIG. 1 shows a sectional view of the flow sensor module. The flow rate sensor module 1 roughly functions as a part of a flow path forming member that forms a flow path of a gas that is a measurement target fluid, and also functions as a gas flow direction of a measurement target flowing in the flow path 2 A sensor unit 10 that detects the flow rate of the gas to be measured by a sensor chip 15 described later mounted in a predetermined mounting direction, and outputs an electric signal corresponding to the detected flow rate; And a sensor holding member 20 attached to the sensor.

The sensor unit 10 is roughly divided into a sensor mounting plate 11 and a sensor chip 15 serving as a sensor body which is mounted on the sensor mounting plate 11 as a bare chip and outputs an electric signal corresponding to a flow rate of a gas to be measured. And a lead pin group 17 for extracting an electric signal output from the sensor chip 15 to the outside.

FIG. 2 is a top view of the sensor mounting plate 11 (FIG. 2).
(A)) and a rear view (FIG. 2 (b)). The sensor mounting plate 11 functions as an insulating substrate.
It is composed of a rectangular ceramic plate having a length of about 12 × a width of about 5 × a thickness of about 0.5 mm.

As shown in FIG. 2A, a sensor mounting land 1 for mounting a sensor chip 15 is provided on one surface of a sensor mounting plate 11 which constitutes a part of the flow path 2.
2 and a bonding pad portion (hereinafter referred to as a pad portion) 13 for electrically connecting to the sensor chip 15 are formed.

On the other surface of the sensor mounting plate 11,
As shown in FIG. 2B, a lead pin connecting land 14 for attaching the lead pin 17 is formed. As shown in FIG. 2A, two sets of the pad portions 13 are arranged on the upstream side and the downstream side in the gas flow direction with respect to the sensor mounting land portion 12. The pad 13 on the upstream side has four strip-shaped pads 13e to 13h.
It is provided with.

Similarly, as shown in FIG. 2 (b), the lead pin connecting land 14 is
2, two sets of the lead pin connecting lands 14a to 14d are arranged on the upstream side and the downstream side in the gas flow direction. Are provided with four lead pin lands 14e to 14h.

The pad portion 13 and the land portion 14 for connecting lead pins are formed by applying a conductive paste to the sensor mounting plate 11.
It is formed by printing on a sheet, can be easily formed, and is suitable for mass production. The pads 13 and the lead pin connection lands 14 are electrically connected via the inside of the sensor mounting plate 11 by via holes or the like. That is, pad 13a and lead pin land 14a, pad 13b and lead pin land 14b,..., Pad 13h and lead pin land 14
The corresponding components are electrically connected to each other, such as h.

FIG. 3 is an external perspective view of the sensor unit 10 in which the sensor chip 15 is die-bonded to the surface of the sensor mounting plate 11 and the lead pins 17 are mounted on the back surface of the sensor mounting plate 11. Sensor chip 1
5 is a thin rectangular parallelepiped having a microheater for generating heat for measuring the heat propagation time, and a thermopile for measuring the heat generated by the microheater and transmitted by the gas to be measured for the flow velocity. It is configured as a chip, and is mounted on the sensor mounting plate 11 as a bare chip.

Further, on the surface, an electrode pad portion 1 to which a wiring drawn from a micro heater and a thermopile is connected.
51 are provided, and the sensor mounting land 1
2 The four electrode pads 151 are arranged on the downstream side of the sensor chip 15 in the gas flow direction in a direction orthogonal to the gas flow direction.
a to 151d, and four electrode pads 151e to 151h arranged on the upstream side of the gas flow direction of the sensor chip 15 in a direction perpendicular to the gas flow direction.

The electrode pad 151a is connected to the pad 13a of the sensor mounting plate 11 by A as a bonding wire.
They are electrically connected by u wires (for example, φ25 μm) 16a. Similarly, the other electrode pads 151b-1
51h is A with respect to the corresponding pads 13b to 13h.
They are electrically connected by u wires 16b to 16h.

The lead pin group 17 includes eight lead pins 17 a to 17 h corresponding to the number of output terminals of the sensor chip 15.
It is composed of And each of these lead pins 1
7a to 17h are attached to the lead pin connecting lands 14 on the back surface of the sensor mounting plate 11, that is, the corresponding lead pin lands 14a to 14h.

More specifically, the base of the lead pin 17a is attached to the corresponding lead pin land 14a, and the base of the lead pin 17h is connected to the corresponding lead pin land 1a.
4h, each lead pin 1
7a to 17h are attached to the lead pin lands 14a to 14h.
17h is erected from the sensor mounting plate 11 toward the bottom surface. The lead pins 17 and the lead pin connecting lands 14 are attached by brazing, soldering, or the like.

FIG. 4 shows a top view (FIG. 4 (a)) and a sectional view (FIG. 4 (b)) of the sensor holding member 20. The sensor holding member 20 includes a base 22 having a substantially rectangular shape in a top view, and a circular protrusion 21 formed to protrude upward from the center of the base 22.
And Four mounting holes 22 b for inserting screws 26 (see FIG. 1) for mounting to the nozzle 2 are provided in the four corners of the base 22. O with ring shape
A ring mounting groove 22a is provided.

On the other hand, a sensor mounting recess 23 for mounting the above-described sensor unit 10 is provided on the upper surface side of the projection 21. This sensor mounting recess 23 is
The sensor mounting plate 11 is formed in the same rectangular shape as the sensor mounting plate 11 so that the sensor mounting plate 11 can be fitted thereto. Therefore, the sensor chip 15 mounted on the sensor mounting plate 11 is fitted by fitting the sensor mounting plate 11 of the sensor unit 10 into the sensor mounting recess 23.
Are mounted on the sensor holding member 20 in a predetermined mounting direction. In this embodiment, FIG.
While the sensor mounting recess 23 has a left-right symmetrical shape, if it is left-right asymmetrical by providing a cutout on one side, an incorrect mounting direction can be prevented. In this case, the sensor mounting plate 11 needs to have a corresponding shape.

Further, at both ends in the longitudinal direction of the bottom surface of the sensor mounting concave portion 23, there are provided through holes 24 for lead pins through which the lead pins 17 mounted on the back surface of the sensor mounting plate 11 pass. When the above-described sensor unit 10 is mounted on the sensor holding member 20 to constitute the flow rate sensor module 1, first, a resin adhesive 27 such as an epoxy resin functioning as a sealing portion is provided on the bottom surface of the sensor mounting concave portion 23. Then, the sensor mounting plate 11 of the sensor unit 10 (see FIG. 3) to which the sensor chip 15 and the lead pins 17 are mounted is fitted into the sensor mounting recess 23.
After the sensor mounting plate 11 is fitted into the sensor mounting recess 23, the lead pin through hole 24 through which the lead pin 17 is passed is filled with an epoxy resin 28 functioning as a through hole sealing part, and the lead pin 17 is held by the sensor. Member 20
The lead pin 17 is fixed in an inserted state such that the lead pin 17 protrudes from the sensor holding member 20 on the back side of the sensor holding member 20 while ensuring an insulating state and an airtight state.
After fixing the lead pin 17, the O-ring mounting groove 2
2a, an O-ring 25 functioning as a passage sealing portion
(See FIG. 1), and the flow velocity sensor module 1 is completed. In addition, the flow path sealing part does not necessarily need to be provided on the flow velocity sensor module 1 side, and may be configured to be provided on the outer surface of the flow path 2.

FIG. 5 shows an external perspective view of the flow channel 2. Channel 2
Has a dimension of, for example, 2.5 mm in width and 7.5 mm in height, and a flow rate sensor module 1 assembled in the direction of an arrow from the bottom in the figure has a sensor mounting hole 2
A (see FIG. 1).

More specifically, the sensor holding member 21 of the flow rate sensor module 1 mounted in the sensor mounting hole 2A
Is fixed to the flow path 2 using the screw 26 (see FIG. 1) inserted into the mounting hole 22a. At this time, the resin adhesive 27 applied to the sensor mounting concave portion 23, the epoxy resin 28
The double airtight structure of the ring 25 can prevent the intrusion of moisture into the flow path 2 and the leakage of the gas to be measured flowing through the nozzle to the outside.

Since the sensor chip 15 is mounted in the flow path 2, it can be prevented from being broken when the flow rate sensor module is mounted on a gas meter or the like. Further, since the sensor mounting recess 23 of the sensor holding member 20 has the same shape as the sensor mounting plate 11 constituting the sensor unit 10, the sensor unit 10 can be easily mounted in a predetermined direction with respect to the sensor holding member 20. . When attaching the flow rate sensor module 1 to the flow path 2, the mounting holes 22b,
The flow velocity sensor module 1 is positioned by the screw holes 2B (see FIG. 1) and the screws 26 provided on the flow path 2 side, and the flow velocity sensor module 1 can be easily attached in a predetermined direction with respect to the flow path 2. Therefore, the sensor chip 15 mounted on the sensor unit 10 can be easily attached to the flow path 2 of the fluidic element in a predetermined direction. In this case, one set (or an odd set)
It is also possible to configure the mounting holes 22b, the screw holes 2B, and the screws 26 to have different diameters so that the mounting position can be more easily positioned.

Then, this mounting state (ie, the state of FIG. 1)
In the above, the sensor chip (that is, the sensor body) 1 mounted on the surface of the sensor mounting plate 11 as an insulating substrate
A sensor output signal from the sensor mounting plate 11 is provided on a pad portion 13 provided on the surface of the sensor mounting plate 11 and a lead pin connecting land portion 14 electrically connected to the pad portion 13 and provided on the back surface of the sensor mounting plate 11. And a lead pin 17 electrically connected to the lead pin connection land portion 14.
Is output to the outside through the sensor mounting plate 11, so that there is no protrusion on the surface of the sensor mounting plate 11 that disturbs the flow path of the fluid to be measured. Accordingly, the pad section 13 can be arranged at an arbitrary position including the upstream in the fluid flow path, and the sensor chip 15 having many output terminals can be used.

Further, as shown in FIG. 2A, the sensor mounting plate 11 is formed of a ceramic substrate, and the sensor mounting land portion 12 provided on the surface of the sensor mounting plate 11 is provided.
Since the pad 13 and the lead pin connection land 14 provided on the back surface of the sensor mounting plate 11 are formed by printing a conductive paste as a conductive material, the sensor mounting land 12 and the pad 13 and the shape and position of the lead pin connection land portion 14 can be set relatively freely.
Can be easily handled.

Also, as shown in FIG. 3, the electrode pads (output terminals) 151 of the sensor chip 15 and the sensor mounting plate 1
Since the pad portion 13 formed on the substrate 1 is connected by the Au wire group 16 as a bonding wire, the electrode pad 151 and the pad portion 13 can be easily electrically connected. The Au wires 16a to 16h constituting the Au wire group 16 are extremely thin, having a diameter of φ25 [μm], and therefore do not disturb the flow of the fluid.
It can be freely arranged in the flow path.

In the above description, the case of wire bonding has been described as a method of mounting a bare chip. However, a solder bump is provided on the lower surface of the sensor chip 15 using a flip chip, and electrical wiring appears on the flow path 2 side. By eliminating the influence, it is possible to reduce the influence on the fluid to be measured.

It is also possible to apply another bare chip mounting method such as TAB.

[0046]

According to the first aspect of the present invention, one surface of the plate-like insulating substrate forms a part of the flow path, and the output terminal of the sensor main body mounted on the sensor mounting land is provided. The pad portion is electrically connected to the pad portion, and the pad portion is electrically connected to the lead pin connection land provided on the other surface of the insulating substrate through the inside of the insulating substrate, and further connected to the lead pin connection land. Since it is electrically connected to the lead pin and outputs the sensor output signal to the outside, it is not necessary to provide the lead pin in the flow path, so that accurate flow velocity measurement can be performed without disturbing the flow of the fluid. .

Furthermore, the arrangement of the pads increases the degree of freedom. Even when a sensor body having a large number of output terminals is used, it is possible to provide a large number of lead pins without being affected by the shape and dimensions of the flow path. This makes it possible to perform various measurements using a multifunctional sensor body.

According to the second aspect of the invention, in addition to the effect of the first aspect, the insulating substrate is formed of a ceramic material, and the sensor mounting land, the pad, and the lead pin connecting land are formed. Is formed by printing a conductive material, a thermally stable, highly reliable sensor mounting plate can be easily mass-produced, and a low-cost, highly reliable flow rate sensor can be provided. .

According to the third aspect of the present invention, there is provided the sensor unit having the sensor mounting plate according to the first or second aspect, wherein the sensor body is mounted on the bare chip in the mounting direction, so that the mounting area is reduced. And the influence on the fluid to be measured can be minimized.

According to the fourth aspect of the invention, in addition to the effect of the third aspect of the present invention, the output terminal of the sensor body and the pad portion are connected by the bonding wire, so that the flow of the fluid accompanying the wiring can be reduced. The influence can be suppressed, accurate measurement can be performed, and a minute sensor unit can be configured.

According to the fifth aspect of the invention, in addition to the effect of the third aspect of the invention, the output terminal of the sensor body and the pad portion are connected by the flip chip, so that the electrical connection is made to the fluid flow path side. Since the part does not directly face, it does not obstruct the flow of the fluid, so that more accurate measurement can be performed and a minute sensor unit can be configured.

According to a sixth aspect of the present invention, there is provided the sensor unit according to any one of the third to fifth aspects, wherein the lead pins are electrically connected to the lead pin connecting lands of the sensor mounting plate. The mounting recess of the sensor holding member is engaged with the sensor mounting plate in a state where the lead pin passes through the through hole for the lead pin to hold the sensor unit in a predetermined direction. As it secures airtightness with the sensor holding member,
Accurate measurement can be performed without leakage of the fluid, and the restriction for the installation of the lead pin is relaxed, so that various measurements using the sensor main body having a large number of output terminals can be performed.

According to the seventh aspect of the invention, in addition to the effect of the sixth aspect, the flow path sealing portion ensures airtightness between the flow path forming member and the sensor holding member. A double airtight structure can be easily realized, and a more accurate measurement can be performed by reliably preventing fluid leakage.

According to the eighth aspect of the present invention, in addition to the effect of the sixth or seventh aspect, the through hole sealing portion ensures the airtightness of the through hole for the lead pin.
A double airtight structure can be easily realized, and a more accurate measurement can be performed by reliably preventing fluid leakage.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view when a flow sensor module is mounted.

FIG. 2 is a top view and a rear view showing the structure of a sensor mounting plate.

FIG. 3 is an external perspective view of a sensor unit.

FIG. 4 is a top view and a cross-sectional view of the sensor holding member.

FIG. 5 is an external perspective view of a flow channel.

FIG. 6 is a top view and a cross-sectional view of a conventional sensor package.

FIG. 7 is an enlarged view of a sensor chip used for a conventional flow rate sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flow rate sensor module 2 Flow path 10 Sensor unit 11 Sensor mounting plate 12 Land for sensor mounting 13 Bonding pad (pad) 14 Land for lead pin connection 15 Sensor chip 151 Electrode pad 16 Au wire (bonding wire) 17 Lead pin Reference Signs List 20 sensor holding member 21 protrusion 22 base 23 sensor mounting recess 24 lead-through hole 25 O-ring 26 screw 27 resin adhesive 28 epoxy resin

Claims (8)

[Claims] 1. A sensor body having a predetermined mounting direction with respect to a flow path forming member for forming a flow path of a fluid to be measured, wherein a sensor output signal from the sensor body is used as flow rate information of the fluid to be measured. A sensor mounting plate used for a flow rate sensor module, comprising: a plate-shaped insulating substrate; and a sensor provided on one surface of the insulating substrate forming a part of the flow path, for mounting the sensor body. A mounting land portion, a pad portion provided on the one surface and electrically connected to an output terminal of the sensor main body, and a pad portion provided on the other surface of the insulating substrate, And a land portion for connecting lead pins electrically connected through the inside of the substrate. 2. The sensor mounting plate according to claim 1, wherein the insulating substrate is formed of a ceramic material,
The sensor mounting plate, wherein the sensor mounting land portion, the pad portion, and the lead pin connecting land portion are formed by printing a conductive material. 3. A sensor unit having the sensor mounting plate according to claim 1 or 2, wherein the sensor main body is mounted on a bare chip in the mounting direction. 4. The sensor unit according to claim 3, wherein the output terminal of the sensor main body and the pad portion are connected by a bonding wire. 5. The sensor unit according to claim 3, wherein the output terminal of the sensor body and the pad are connected by a flip chip. 6. The sensor unit according to claim 3, further comprising: a lead pin attached to the sensor mounting plate in a state of being electrically connected to a lead pin connecting land portion; and the sensor. A sensor holding member having a mounting recess engaged with a mounting plate and holding the sensor unit in a predetermined direction, and a lead pin through-hole for passing the lead pin, between the sensor unit and the sensor holding member; A flow rate sensor module, comprising: a sealing portion for ensuring airtightness. 7. The flow rate sensor according to claim 6, further comprising a flow path sealing portion for ensuring airtightness between the flow path forming member and the sensor holding member. module. 8. The flow rate sensor module according to claim 6, further comprising a through hole sealing portion for ensuring airtightness of the lead pin through hole.