JP7064460B2 - Package type flow sensor - Google Patents

Description

The present invention relates to a packaged flow sensor.

A flow sensor that detects the flow rate, flow velocity, and flow direction of a fluid is used. The flow sensor includes, for example, a heater on a thin film (membrane) and a sensor unit having a thermopile arranged so as to sandwich the heater. In the flow sensor provided with such a sensor unit, when the heat distribution generated by the heater heating the thin film is disturbed by the flow of the fluid, the disturbance is measured as the difference in the thermoelectromotive force generated by the thermopile. Since the sensor part uses a membrane, it can be said that it is a part that is easily damaged by physical contact or the like.

For example, Patent Document 1 discloses a flow sensor formed integrally with a flow path through which a fluid passes. Patent Document 2 discloses a flow sensor that is formed as a separate body from the flow path and has a sensor portion for detecting the flow velocity exposed to the outside. The flow sensor disclosed in Patent Document 2 is provided in the flow path, and the flow rate is detected together with the cross-sectional area of the flow path.

Japanese Patent No. 5652315 Japanese Patent No. 6435389

Since the flow sensor disclosed in Patent Document 1 is formed integrally with the flow path, it is difficult to reduce the size and the manufacturing cost is high. Since the flow sensor disclosed in Patent Document 2 is formed as a separate body from the flow path, it can be easily miniaturized. However, the flow sensor disclosed in Patent Document 2 is difficult to handle because the sensor portion exposed to the outside is easily damaged by physical contact or the like.

One aspect of the disclosed technique is to provide a packaged flow sensor that can be formed compact and easy to handle.

One aspect of the disclosed technique is exemplified by the following packaged flow sensors. This package type flow sensor has a flow sensor chip having a sensor unit for detecting the flow velocity of a fluid, a case member having a hollow portion that opens toward the outside and houses the flow sensor chip, and a surface facing the opening. The flow sensor chip is placed therein, and a substrate that covers the opening is provided. One of the case member or the substrate has a through hole that communicates with the outside, and the sensor portion has the through hole. The hole and the hollow portion are characterized in that a flow path for guiding the fluid is formed in the sensor portion.

The sensor portion of the flow sensor chip has a delicate component for detecting the flow velocity of the fluid mounted on its surface, and is easily damaged by physical contact or the like. According to the disclosed technique, by accommodating the flow sensor chip in the hollow portion in the case member, the sensor portion of the flow sensor chip can be protected from physical contact or the like, so that the flow sensor can be easily handled. Further, since the package type flow sensor is not integrally formed with the flow path, it is easier to miniaturize than the flow sensor integrally formed with the flow path. Since the package itself is small, even if this package type flow sensor is incorporated in the flow path formed as a separate body and the flow rate is detected from the detected flow rate, the degree of freedom of attachment to the flow path is improved and the flow rate is improved. Even if the structure includes the road, it is small.

Since the through hole and the hollow portion form a flow path for guiding the fluid to the sensor portion, the fluid introduced into the hollow portion from the through hole passes over the sensor portion. Since the flow path guides the fluid to the sensor unit, even if the sensor unit is housed in the case member, the deterioration of the detection accuracy by the sensor unit is suppressed. The through hole may be provided in the case member or may be provided in the substrate.

The disclosed technique may have the following features: The through hole is provided in the substrate, is provided on the surface of the substrate opposite to the surface on which the flow sensor chip is placed, and the through hole is provided with a land formed to guide the fluid. It is characterized by that. By having such a feature, the fluid can be positively guided to the through hole by the land, and the detection accuracy of the flow sensor chip can be improved.

The disclosed technique may have the following features: The through hole is provided in the substrate, is provided on the surface of the substrate opposite to the surface on which the flow sensor chip is placed, and is provided with a land formed so as to surround the periphery of the through hole. It is a feature. In such a case, the package type flow sensor is mounted on a second board having wiring for connecting electronic components, and the second board is placed on the second board at a position corresponding to the area surrounded by the land. A through hole is provided, and the fluid is allowed to flow from the surface of the second substrate opposite to the surface on which the package type flow sensor is mounted, through the second through hole and the through hole, and the hollow portion. You may be guided to. By adopting such a configuration, the package type flow sensor can be provided in a region different from the region where the fluid flows, so that the package type flow sensor can disturb the fluid flow (cause turbulence). It will be reduced. Further, by adopting such a configuration, the package type flow sensor can be mounted on the same surface as the surface to which the electronic component is connected in the second substrate, so that the second substrate can be mounted on one side. It can be an implementation.

The disclosed technique may have the following features: On the surface of the second substrate opposite to the surface on which the package-type flow sensor chip is placed, a filter member that prevents substances other than the fluid from entering the hollow portion is provided in the second through hole. It is provided so as to cover the top. By having such a feature, water other than fluid, dust, dust, etc. are suppressed from entering the hollow portion, so that the detection accuracy is lowered due to contact of water, dust, dust, etc. with the flow sensor chip. Failure of the flow sensor chip is suppressed.

The disclosed technique may have the following features: The second through hole has a first opening that opens at a position corresponding to the area surrounded by the land and a second opening that opens on a surface opposite to the surface on which the package type flow sensor is placed. A portion and a flow path formed in the second substrate and guiding the fluid to the hollow portion by connecting the first opening and the second opening are included. By having such a feature, the amount of the fluid introduced into the hollow portion can be suitably controlled by designing the shape of the flow path so as to meet a desired purpose.

This package type flow sensor can be formed in a small size and is easy to handle.

FIG. 1 is an exploded perspective view of the sensor package according to the embodiment. FIG. 2 is a view of the flow sensor chip as viewed from above. FIG. 3 is a cross-sectional view taken along the line AA in FIG. FIG. 4 is a first diagram schematically showing a method of measuring the flow velocity by the flow sensor chip. FIG. 5 is a second diagram schematically showing a method of measuring the flow velocity by the flow sensor chip. FIG. 6 is a plan view of the sensor package according to the embodiment. FIG. 7 is a diagram schematically showing the flow of air introduced from the ventilation holes in the sensor package according to the embodiment. FIG. 8 is a view of the substrate of the sensor package according to the embodiment as viewed from above. FIG. 9 is a view of the substrate of the sensor package according to the embodiment as viewed from below. FIG. 10 is a bottom view of an example of a sensor package having a land extending in a direction orthogonal to the direction of the wind in the embodiment. FIG. 11 is a diagram schematically showing a flow of air introduced into a vent in a sensor package having a land extending in a direction orthogonal to the direction of the wind. FIG. 12 is a diagram illustrating variations of lands extending in a direction orthogonal to the direction of the wind. FIG. 13 is a diagram showing an example of a method for manufacturing a sensor package according to an embodiment. FIG. 14 is a diagram illustrating a sheet in which a plurality of lids are connected in succession. FIG. 15 is an exploded perspective view showing an example of the sensor package according to the first modification. FIG. 16 is a view of the sensor package according to the first modification as viewed from below. FIG. 17 is a diagram schematically showing the flow of air introduced from the ventilation holes in the sensor package according to the first modification. FIG. 18 is a bottom view of an example of the sensor package according to the second modification. FIG. 19 is a diagram showing an example of another shape of the land. FIG. 20 is a first diagram showing an example of a case where a land provided so as to be orthogonal to the direction of the wind is applied to the sensor package according to the second modification. FIG. 21 is a diagram showing an example of a case where a land provided so as to be orthogonal to the direction of the wind is applied to the sensor package according to the second modification. FIG. 22 is a bottom view of an example of the sensor package according to the third modification. FIG. 23 is a diagram schematically showing the flow of air introduced from the ventilation holes in the sensor package according to the third modification. FIG. 24 is a diagram showing an example of a configuration in which a waterproof / dustproof mesh is provided on the back surface of the substrate in the sensor package according to the third modification. FIG. 25 is a diagram showing an example of a configuration in which the distance between the ventilation holes is substantially changed in the sensor package according to the third modification. FIG. 26 illustrates a configuration in which the wind direction adjusting member is provided on the back surface of the substrate in the sensor package according to the third modification. FIG. 27 is a diagram showing variations in the shapes of lands and vents.

<Embodiment>
Hereinafter, the sensor package according to the embodiment will be described with reference to the drawings. FIG. 1 is an exploded perspective view of the sensor package according to the embodiment. The sensor package 100 exemplified in FIG. 1 includes a substrate 1, a flow sensor chip 2, and a lid 3. Hereinafter, in the present specification, the substrate 1 side is the lower side and the lid 3 side is the upper side. In the present specification, the direction along one side of the plate-shaped substrate 1 is also referred to as an X direction, the direction along the other side is also referred to as a Y direction, and the vertical direction is also referred to as a Z direction. The sensor package 100 is an example of a “package type flow sensor”.

(Flow sensor chip 2)
The flow sensor chip 2 is a sensor that measures the flow velocity of a fluid (for example, a gas). FIG. 2 is a view of the flow sensor chip as viewed from above, and FIG. 3 is a sectional view taken along line AA in FIG. The flow sensor chip 2 includes a main body 21 and a membrane 22. The main body 21 is formed in a hollow shape (mortar shape) having an open upper surface, and the material thereof is, for example, silicon. The membrane 22 is a thin film, and as illustrated in FIG. 3, has a hollow structure at the opening of the main body 21. The membrane 22 is provided with a heater 23 and thermopile 24, 24. The heater 23 and the thermopile 24, 24 are arranged side by side in a row along the Y direction. The contacts at one ends of the thermopile 24, 24 are arranged at positions overlapping with the main body 21. When distinguishing each of the thermopile 24 and 24, one of the thermopile 24 and 24 is referred to as a thermopile 241 and the other is referred to as a thermopile 242.

The heater 23 is a heater that heats the membrane 22. Since the membrane 22 is a thin film, it has a small heat capacity and is efficiently heated by the heater 23. The thermopile 24, 24 is a thermocouple that generates a thermoelectromotive force by receiving heat from the membrane 22. Since the contact point at one end of the thermopile 24, 24 is on the main body 21, the temperature difference between the membrane 22 and the main body 21 can be detected as the thermoelectromotive force. The thermopile 24, 24 produces a higher thermoelectromotive force at higher temperatures. Further, when all of the thermopile 24 and 24 have the same temperature, the thermoelectromotive forces generated by the thermopile 24 and 24 are equal. The flow sensor chip 2 is, for example, a thermal flow sensor that heats the membrane 22 by a heater 23 and measures the flow rate based on the difference in thermoelectromotive force of the thermopile 24 and 24 caused by the difference in heat distribution in the membrane 22. The flow sensor chip 2 is, for example, a Micro Electro.
Manufactured by Mechanical Systems (MEMS).

The membrane 22 of the flow sensor chip 2 is also provided with powered terminals 231 and 231 connected to both ends of the heater 23 to receive power supplied from the external power source 40 to the heater 23. Further, the membrane 22 is also provided with terminals 243 and 242 to be measured for measuring the difference V _out of the thermoelectromotive force generated by each of the thermopile 24 and 24. The thermopile 24, 24 and the terminal to be measured 243, 243 are connected in series by the wiring 25. The flow sensor chip 2 is, for example, a surface mount type flow sensor in which the membrane 22 provided with the heater 23 and the thermopile 24, 24 is exposed to the outside. The membrane 22, the heater 23, and the thermopile 24, 24 are examples of the “sensor unit”.

4 and 5 are diagrams schematically showing a method of measuring the flow velocity by the flow sensor chip. FIG. 4 illustrates a state in which no wind is blowing around the flow sensor chip 2. When no wind is blowing around the flow sensor chip 2, the temperature drops as the position from the heater 23 moves away, and as illustrated by the heat distribution H1, the heat distribution in the membrane 22 becomes uniform around the heater 23. .. Therefore, both the thermopile 24 and 24 are heated to the same temperature by the heater 23, and the thermoelectromotive force generated by the thermopile 24 and 24 is also the same.

FIG. 5 illustrates a state in which wind is blowing around the flow sensor chip 2. Assuming that one of the thermopile 24 and 24 is the thermopile 241 and the other is the thermopile 242, FIG. 5 illustrates a state in which the wind is blowing from the thermopile 241 toward the thermopile 242. Since the upstream side of the wind is cooled by the wind and the temperature drops, the heat distribution in the membrane 22 shifts to the downstream side from the upstream side of the sensor 23 (the downstream side is the upstream side) as illustrated by the heat distribution H2. It gets hotter). Therefore, the temperature of the thermopile 242 located on the downstream side of the heater 23 is higher than that of the thermopile 241 located on the upstream side of the heater 23. As a result, there is _a difference between the thermoelectromotive force V1 of the _thermopile 241 and the thermoelectromotive force V2 of the thermopile 242.

As described above, the thermopile force of the thermopile 24 and 24 increases as the temperature rises, and the thermopile 24 located on the downstream side of the wind has a higher temperature than the thermopile 24 located on the upstream side of the wind. Therefore, by measuring the difference between the electromotive force V ₁ of the thermopile 241 and the electromotive force V ₂ of the thermopile 242 (that is, V2 _- V ₁ ), the flow sensor chip 2 detects the direction of the wind and the strength of the wind. Can detect the power.

When V2 _- V ₁ is positive, the temperature of the thermopile 242 is higher than that of the thermopile 241. Therefore, the flow sensor chip 2 indicates that the wind is blowing from the thermopile 241 toward the thermopile 242. Can be detected. Further, when V ₂ -V ₁ is negative, the temperature of the thermopile 241 is higher than that of the thermopile 242, so that the flow sensor chip 2 is blowing in the direction from the thermopile 242 toward the thermopile 241. Can be detected. Further, when V ₂ -V ₁ is 0 (zero), since all the thermopile 24 and 24 have the same temperature, the flow sensor chip 2 is not blowing (or is blowing wind). Is less than the lower limit of the detection range). Further, the flow sensor chip ₂ can detect that the larger the value of V2 _- V1, the stronger the wind is blowing.

(Lid 3)
The lid 3 is a lid that covers the flow sensor chip 2 from above. The lid 3 exemplified in FIG. 1 has a hollow structure, and the sensor 12 can be accommodated in the hollow region. The lid 3 illustrated in FIG. 1 is formed in a hollow rectangular parallelepiped shape with an open bottom surface, but the shape of the lid 3 is not limited to a rectangular parallelepiped, and is a polygonal column such as a cylindrical shape or a pentagonal prism. May be good. The shape of the lid 3 may have a cavity inside which the flow sensor chip 2 can be accommodated. The material of the lid 3 is not particularly limited, but any material may be used as long as it has rigidity that can protect the housed flow sensor chip 2 from external impacts and the like and can form a flow path in the package. It may be metal, plastic, ceramic, silicon, or the like. If the material of the lid 3 has conductivity such as metal, there is an advantage that resistance to electromagnetic noise can be obtained.

FIG. 6 is a plan view of the sensor package according to the embodiment. FIG. 7 is a diagram schematically showing the flow of air introduced from the ventilation holes in the sensor package according to the embodiment. FIG. 7 is a cross-sectional view taken along the line BB of FIG. In FIG. 6, the flow sensor chip 2 housed in the lid 3 and the thermopile 24, 24 provided on the upper surface of the flow sensor chip 2 are shown by dotted lines. Two ventilation holes 31 and 31 are provided on the upper surface of the lid 3. The ventilation holes 31 and 31 are holes that penetrate the upper surface of the lid 3 in the thickness direction, and are arranged along the Y direction on the upper surface of the lid 3. It can also be said that the ventilation holes 31 and 31 communicate the hollow region of the lid 3 with the outside. As can be understood with reference to FIG. 6, the flow sensor chip 2 is housed in the lid 3 so as to be located between the ventilation holes 31 and 31 in a plan view of the sensor package 100 as viewed from above. As a result, the ventilation holes 31, the thermopile 241 and the thermopile 242, and the ventilation holes 31 are arranged in this order in a row along the Y direction.

When the vents 31, 31 and the thermopile 24, 24 are arranged in this way, as illustrated in FIG. 7, the air introduced into the lid 3 from one vent 31 is on the two thermopile 24, 24. Is discharged from the lid 3 through the other ventilation hole 31. That is, on the upper surface of the lid 3, the ventilation holes 31, 31 and the hollow region of the lid 3 can form a flow path through which wind passes on the two thermopile 24, 24. Lid 3 is "
This is an example of a "case member". The hollow region of the lid 3 is an example of a "hollow portion".

(Board 1)
The substrate 1 is a substrate on which the flow sensor chip 2 is placed on one surface (the surface facing the opening of the lid 3). The substrate 1 may have, for example, a connection terminal for connecting the flow sensor chip 2 and an external device. The substrate 1 may be a printed circuit board or a ceramic substrate. Further, the substrate 1 may be a rigid substrate or a flexible substrate. In FIG. 1, the substrate 1 is formed in the shape of a rectangular plate, but the shape of the substrate 1 is not limited to such a shape. The substrate 1 may be formed in another shape such as a circular shape, a triangular shape, or a pentagonal shape. The substrate 1 is preferably formed in a shape capable of covering the entire opening of the lid 3.

FIG. 8 is a view of the substrate of the sensor package according to the embodiment as viewed from above, and FIG. 9 is a view of the substrate of the sensor package according to the embodiment as viewed from below. In FIG. 8, the flow sensor chip 2 mounted on the upper surface 11 of the substrate 1 is also shown. On the upper surface 11, the substrate 1 has the feeding terminals 112 and 112 electrically connected to the powered terminals 231 and 231 of the sensor 12 and the measuring terminals 113 electrically connected to the measured terminals 243 and 243 of the sensor 12. , 113. The power supply terminals 231 and 231 of the sensor 12, the power supply terminals 112 and 112, and the measurement terminals 243 and 243 and the measurement terminals 113 and 113 are connected by wire bonding using, for example, a metal wire W1. The metal wire W1 is formed of, for example, gold. Further, the substrate 1 has lands 122, 122, 122, 122 electrically connected to the feeding terminals 112, 112 and the measuring terminals 113, 113 provided on the upper surface 11 on the lower surface 12. The substrate 1 is an example of a “substrate”.

In an embodiment, the lower surface 12 of the substrate 1 may further have lands extending in a direction orthogonal to the direction of the wind. FIG. 10 is a view from below of an example of a sensor package having a land extending in a direction orthogonal to the direction of the wind in the embodiment, and FIG. 11 is a view extending in a direction orthogonal to the direction of the wind. It is a figure which shows typically the flow of the air introduced into the ventilation hole in the sensor package provided with a land. In FIG. 11, the sensor package 100 is connected on the substrate 200 by a solder 204. That is, the lands 122 and 1221 of the sensor package 100 and the lands on the substrate 200 are connected by the solder 204.

The land 1221 is provided so as to extend in a direction orthogonal to the direction of the wind (extend in the X direction). Therefore, the wind passing through the portion where the sensor package 100 and the substrate 200 are connected is hindered by the land 1221, the solder 204 connecting the land 1221 and the substrate 200, and the substrate 200, and travels upward. Will change. As a result, the amount of wind introduced into the lid 3 from the ventilation holes 31 can be increased, and thus the sensitivity of the sensor package 100 can be improved.

In FIGS. 10 and 11, lands extending in a direction orthogonal to the direction of the wind are exemplified at substantially the center of the lower surface 12 in the Y direction, but such lands may be provided at other positions. FIG. 12 is a diagram illustrating variations of lands extending in a direction orthogonal to the direction of the wind. In FIG. 12A, lands 1222 and 1222 extending in a direction orthogonal to the wind direction (extending in the X direction) are provided at both ends of the lower surface 12 in the Y direction. In FIG. 12B, lands 1223 formed in an annular shape (frame shape) are provided along the outer periphery of the lower surface 12 so as to surround the plurality of lands 122 provided on the lower surface 12.

Land 1222 exemplified in FIG. 12 (A) and land 1223 exemplified in FIG. 12 (B).
By changing the traveling direction of the wind passing through the portion where the sensor package 100 and the substrate 200 are connected to the direction toward the ventilation hole 31, as in the case of the land 1221 exemplified in FIGS. 10 and 11. The amount of wind introduced from the pores 31 into the lid 3 can be increased.

As illustrated in FIG. 12B, by surrounding the plurality of lands 122 with the lands 1223, it is possible to prevent moisture and foreign matter from adhering to the lands 122. For example, if moisture or a conductive foreign substance intervenes between the lands and electrically short-circuits the lands, a failure will occur, but since the area of the lands 122 is protected by being surrounded by the lands 1223, the failure will occur. It's hard. Not only foreign matter but also corrosive gas that corrodes the land 122 makes it difficult to receive the influence. Further, the land 1223 may be used as a terminal for electrically connecting the sensor package 200 and the substrate 200. For example, if the land 1223 is a ground terminal, the land 1223 can protect the land 122 from electromagnetic noise and the like.

(Manufacturing method of sensor package 100)
FIG. 13 is a diagram showing an example of a method for manufacturing a sensor package according to an embodiment. Hereinafter, an example of a method for manufacturing the sensor package 100 will be described with reference to FIG.

In FIG. 13A, the substrate B1 is prepared as the first step. The substrate B1 may be a printed circuit board or a ceramic substrate. Further, the substrate B1 may be a rigid substrate or a flexible substrate. The substrate B1 is provided with as many pairs of power supply terminals 112 and 112 and measurement terminals 113 and 113 as the number of flow sensor chips 2 to be die-bonded in FIG. 13B can be connected.

In FIG. 13B, as the second step, the flow sensor chip 2 is fixed on the substrate B1 by die bonding. In FIG. 13C, as the third step, the flow sensor chip 2 fixed by die bonding and the substrate B1 are connected by wire bonding using a metal wire W1. In wire bonding, the power supply terminals 231 and 231 of the flow sensor chip 2 and the power supply terminals 112 and 112 on the board B1 are connected by wire bonding, and the measured terminals 243 and 243 of the flow sensor chip 2 and the measurement on the board B1 are measured. The terminals 113 and 113 are connected by wire bonding.

In FIG. 13D, as the fourth step, the lid 3 is provided so as to cover the flow sensor chip 2 from above. The lid 3 is adhered to the substrate B1 with an adhesive or the like. When the material of the lid 3 is a metal, if the adhesive is a conductive material such as solder or silver paste, the electromagnetic shielding effect of the lid 3 can be obtained. In FIG. 13, lids 3 individually separated from each of the flow sensor chips 2 are used, but as illustrated in FIG. 14, a sheet 32 in which a plurality of lids 3 are connected in succession is used. It is also good. Such a sheet 32 can be manufactured by a general printed circuit board or ceramic substrate material and manufacturing method.

In FIG. 13E, as the fifth step, dicing is performed from the lower surface of the substrate B1 (from the surface of the substrate B1 opposite to the surface to which the flow sensor chip 2 is fixed) to separate the sensor package 100. At this time, by closing the ventilation hole 31 of the lid 3 with the tape T1, it is possible to prevent water from entering the inside of the lid 3 during dicing.

The sensor package can be manufactured by performing each of the steps of FIGS. 13 (A) to 13 (E) described above.

<Action and effect of the embodiment>
The sensor package 100 according to the embodiment accommodates the flow sensor chip 2 mounted on the substrate 1 inside the lid 3. As a result, the flow sensor chip 2 is protected from external physical contact and the like by the lid 2 and the substrate 1. Therefore, the sensor package 100 can be handled more easily than the flow sensor in which the membrane 22 is exposed to the outside. Further, since the sensor package 100 can protect the flow sensor chip 2 from physical contact from the outside by the lid 3, the sensor package 100 can be used in various places.

Since the sensor package 100 according to the embodiment is not formed integrally with the flow path through which the fluid passes, it is easier to miniaturize than the flow sensor formed integrally with the flow path.

In the sensor package 100 according to the embodiment, by arranging the ventilation holes 31, 31 and the thermopile 24, 24 in a line along the Y direction, a flow path suitable for measuring the flow velocity and the flow direction of the fluid can be formed.

<First modification>
In the embodiment, the lid 3 is provided with ventilation holes 31 and 31. In the first modification, a sensor package in which vents are provided on the substrate will be described. Hereinafter, the sensor package according to the first modification will be described with reference to the drawings. In the following description, the same components as those in the embodiment are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 15 is an exploded perspective view showing an example of the sensor package according to the first modification. The sensor package 100a exemplified in FIG. 15 is provided so that the ventilation holes 31a penetrate the substrate 1a in the thickness direction. The lid 3a is different from the lid 3 of the sensor package 100 according to the embodiment in that the lid 3a does not have the ventilation holes 31 and 31. FIG. 16 is a view of the sensor package according to the first modification as viewed from below. In FIG. 16, the flow sensor chip 2 mounted on the substrate 1a and housed in the lid 3a is shown by a dotted line. In the first modification, the ventilation holes 31a, the flow sensor chip 2, and the ventilation holes 31a are arranged side by side in a row along the Y direction, as in the embodiment.

FIG. 17 is a diagram schematically showing the flow of air introduced from the ventilation holes in the sensor package according to the first modification. In FIG. 17, in the sensor package 100a, a land 122 provided on the lower surface 12a of the substrate 1a and a land 203 provided on the back surface 202 of the substrate 200 are connected by a solder 204.

The surface 201 of the substrate 200 is a surface on which various electronic components such as capacitors and operational amplifiers are mounted. That is, the sensor package 100a according to the first modification is mounted on the back surface 202, which is a surface different from the front surface 201 on which electronic components such as capacitors and operational amplifiers are mounted. In other words, it can be said that various components including the sensor package 100 are mounted on both sides of the substrate 200. By mounting in this way, the number of electronic components that can be mounted on the substrate 200 increases, and as a result, the substrate 200 can be miniaturized. Further, the sensor package 100a and the electronic circuit can be mounted on one side only on the surface 202, and the productivity can be improved by mounting only on one side. When the sensor package 100 according to the embodiment is also mounted on the board 200, it is also mounted on the back surface 202 of the board 200. The substrate 200 is an example of a "second substrate".

By connecting the sensor package 100a and the substrate 200 in this way, a gap is created between the substrate 1a and the substrate 200. In the first modification, the wind passing through the gap is introduced into the lid 3a through one of the ventilation holes 31a, passes over the thermopile 24, 24 of the flow sensor chip 2, and passes through the other of the ventilation holes 31a. 3 It is discharged to the outside.

The sensor package 100a according to the first modification can also suitably measure the flow velocity of the fluid and the flow direction of the fluid while protecting the flow sensor chip 2 by the lid 3a. Further, in the sensor package 100a, the ventilation holes 31a and 31a are located between the substrate 1a and the substrate 200 (gap). This gap is caused by soldering between the land 122 and the land 203, and is a very narrow gap. Therefore, in the sensor package 100a according to the first modification, dust, dust, and the like are suppressed from entering the lid 3a through the ventilation holes 31a.

<Second modification>
In the second modification, a configuration in which a ventilation hole is provided in the substrate will be described as in the first modification. Hereinafter, the sensor package according to the second modification will be described with reference to the drawings. In the following description, the same components as those of the embodiment and the first modification are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 18 is a bottom view of an example of the sensor package according to the second modification. In the sensor package 100b exemplified in FIG. 18, the land 122a and the land 122b are provided in place of the land 122. The lands 122a and 122a are formed so as to extend in the X direction. The lands 122a and 122a are arranged between the ventilation holes 31a and 31a in the Y direction along the ventilation holes 31a. That is, in the Y direction, the lands 122a, the ventilation holes 31a, the ventilation holes 31a, and the lands 122a are arranged side by side in this order. The lands 122b and 122b are arranged between the lands 122a and 122a in the Y direction. Further, in the X direction, the land 122a is formed longer than the ventilation hole 31a.

By forming the land 122a in this way, the wind that has entered between the substrate 1a and the substrate 200 of the sensor package 100b collides with the land 122a. The wind that hits the land 122a is guided to the ventilation hole 31a by the land 122a. Therefore, the sensor package 100b according to the second modification can increase the efficiency of introducing wind into the ventilation holes 31a, and can increase the sensitivity of the sensor package 100b.

In FIG. 18, the land 122a is formed in a rectangular shape in a plan view, but the shape of the land 122a is not limited to such a shape. The shape of the land 122a can be variously deformed. FIG. 19 is a diagram showing an example of another shape of the land. In FIG. 19, the land 122a in which the ventilation hole 31a is formed in a circular shape in a plan view is connected to both ends of the annular portion 122a1 and the annular portion 122a1 that surround a part around the circularly formed ventilation hole 31a. , Includes a wall portion 122a2 extending in the X direction. The annular portion 122a1 includes an opening 122a3 that opens outward from the ventilation hole 31a in the Y direction. Even with such a land 122a, the efficiency of introducing wind into the ventilation hole 31a can be increased, and by extension, the sensitivity of the sensor package 100b can be increased. That is, the shape of the land 122 desired to form a wind flow path between the sensor package 100b and the substrate 200, improving the characteristics of the sensor package 100b. The land 122 physically and electrically connects the sensor package 100b and the substrate 100 by soldering 204, but even if there is a land 122 that does not have an electrical connection function mainly for the purpose of forming a flow path by soldering. good.

The sensor package 100b is manufactured in the same manner as the manufacturing method shown in FIG. However, since the substrate 1a has the vent holes 31a instead of the lid 3a, in FIG. 13E, the substrate 1a side is closed with the tape T1 to the inside of the lid 3a during dicing. Water is suppressed from entering.

20 and 21 are diagrams showing an example of a case where a land provided so as to be orthogonal to the direction of the wind is applied to the sensor package according to the second modification. FIG. 20 shows an example in which an annular land 1223 surrounding a plurality of lands 122 is applied to the sensor package 100b according to the second modification. By hindering the progress of the wind by the land 1223, the path of the wind can be directed to the ventilation hole 31a, and the amount of the wind introduced into the lid 3 can be increased.

FIG. 21 illustrates an annular land 1224 formed by connecting the wall portions 122a2 of the two lands 122a exemplified in FIG. 18 at their ends in the X direction, respectively. The lands 1224 are formed so as to surround the plurality of lands 122. Similar to the land 1223, such a land 1224 also suppresses the adhesion of moisture and foreign matter to the land 122. Further, the land 1224 can also direct the wind path to the ventilation hole 31a, and can increase the amount of wind introduced into the lid 3.

<Third modification example>
In the second variant, a portion of the perimeter of the vent was surrounded by lands. In the third modification, a configuration in which the entire circumference of the ventilation hole is surrounded by a land will be described with reference to the drawings. In the following description, the same configurations as those of the embodiment, the first modification, or the second modification are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 22 is a bottom view of an example of the sensor package according to the third modification. The sensor package 100c exemplified in FIG. 22 is different from the sensor package 100b according to the second modification in that the land 122c is provided in place of the land 122a.

The lands 122c and 122c are formed in a frame shape so as to surround the periphery of the ventilation holes 31a. The ventilation holes 31a are open inside the lands 122c and 122c formed in a frame shape when the sensor package 100c is viewed from below.

FIG. 23 is a diagram schematically showing the flow of air introduced from the ventilation holes in the sensor package according to the third modification. In the third modification, the sensor package 100c is provided on the surface 201a of the substrate 200a, unlike the embodiment, the first modification, and the second modification. That is, the sensor package 100c according to the third modification is provided on the same surface 201a as electronic components such as capacitors and operational amplifiers.

The substrate 200a is provided with a land 203a having a through hole 205 penetrating in the thickness direction of the substrate 200a at a position corresponding to a frame defined by the lands 122c and 122c. That is, the land 203a is formed in a frame shape in a plan view. Since the lands 122c and the lands 203a are formed in a frame shape, the solder 204 is also formed in a frame shape in the third modification. Therefore, when the sensor package 100c mounted on the substrate 200a is viewed from below the substrate 200a, it passes through the through hole 205 of the substrate 200a, the inside of the frame defined by the solder 204, and the inside of the frame defined by the land 122c. , Vents 31a can be seen. In other words, it can be said that the inside and the outside of the lid 3 communicate with each other by the through hole 205 of the substrate 200a, the inside of the frame defined by the solder 204, the inside of the frame defined by the land 122c, and the ventilation hole 31a. .. The through hole 205 is an example of the “second through hole”.

In the third modification, the wind is introduced into the lid 3 through the through hole 205, the frame defined by the solder 204, the frame defined by the land 122c, and the ventilation hole 31a. The wind introduced into the lid 3 passes over the thermopile 24, 24 of the flow sensor chip 2, and is discharged to the outside of the lid 3 through a ventilation hole 31a different from that at the time of introduction.

In the third modification, the sensor package 100c is provided on the front surface 201a of the substrate 200a, and the wind flowing through the back surface 202a of the substrate 200a can be introduced from the ventilation holes 31a. Therefore, according to the third modification, the sensor package 100c can be mounted on the surface 201a, which is the same surface as the electronic component, so that the substrate 200a can be mounted on one side.

In the third modification, neither the electronic component nor the sensor package 100c can be provided on the back surface 202a side of the substrate 200a which is the flow path of the wind to be detected by the sensor package 100c. Therefore, the generation of turbulence due to the collision between the wind targeted by the sensor package 100a and the sensor package 100c or the electronic component is suppressed.

The sensor package 100c according to the third modification can be further deformed. 24 to 27 are views showing variations of the third modification. Hereinafter, variations of the sensor package 100c according to the third modification will be described with reference to FIGS. 24 to 27.

FIG. 24 is a diagram showing an example of a configuration in which a waterproof / dustproof mesh is provided on the back surface of the substrate in the sensor package according to the third modification. The waterproof / dustproof mesh 300 is a member that allows wind to pass through while removing dust, dust, water, and the like contained in the passing wind. The waterproof / dustproof mesh 300 is provided so as to cover the through hole 203 of the substrate 200a. Since the through hole 203 is covered with the waterproof / dustproof mesh 300, the wind to be detected by the sensor package 100c must pass through the waterproof / dustproof mesh 300 and then be introduced into the lid 3 through the ventilation hole 31a. become. According to such a configuration, it is possible to suppress the intrusion of dust, dust, water and the like into the lid 3. The waterproof / dustproof mesh 300 is an example of a “filter member”. Dust, dust, water, etc. are examples of "substances other than fluids".

FIG. 25 is a diagram showing an example of a configuration in which the distance between the ventilation holes is substantially changed in the sensor package according to the third modification. In FIG. 25, the through hole 205 is bent in the substrate 200a to substantially increase the distance between the ventilation holes 31a and 31a of the sensor package 100c. In this way, by appropriately adjusting the distance between the ventilation holes 31a and 31a, the sensitivity of the wind due to the sensor package 100c can be adjusted. The opening surrounded by the land 203a of the through hole 203 is an example of the “first opening”. The opening on the lower surface 202a side of the substrate 200a of the through hole 203 is an example of the “second opening”.

FIG. 26 illustrates a configuration in which the wind direction adjusting member is provided on the back surface of the substrate in the sensor package according to the third modification. The wind direction adjusting member 400 exemplified in FIG. 26 is provided with a roof portion 401 provided at a position located at a predetermined distance in the Z direction from the through hole 203 of the substrate 200. The wind direction adjusting member 400 has wall portions 402 and 402 that are erected in the Z direction. The wall portions 402 and 402 are arranged so as to be lined up in this order with the through hole 203, the wall portion 402, the wall portion 402, and the through hole 203 in the Y direction. By providing such a wind direction adjusting member 400, the wind can be guided to the through hole 203 and the ventilation hole 31a by the roof portion 401 and the wall portion 402, and the detection accuracy of the sensor package 100c can be improved.

FIG. 27 is a diagram showing variations in the shapes of lands and vents. In FIG. 22, the lands 122c and the ventilation holes 31a formed in a rectangular shape in the plan view from the Z direction are exemplified, but in FIG. 27, the lands 122c and the ventilation holes 31a formed in a circle in the plan view from the Z direction are illustrated. Is exemplified. The land 122c exemplified in FIG. 27 is formed in a cylindrical shape so as to stand upright in the Z direction from the circumferential portion of the circularly formed ventilation hole 31a. In the above, the lands 122c and the ventilation holes 31a formed in a rectangular shape or a circle are mentioned, but the shapes of the lands 122c and the ventilation holes 31a are not limited to the rectangle or the circle. In the third modification, the land 122c may be formed in a frame shape surrounding the ventilation hole 31a.

<Other variants>
In the embodiment described above and the first to third modifications, the number of ventilation holes is two, but three or more ventilation holes may be provided. Further, in the embodiment and the first to third modifications, the thermopile is used as the element for detecting the heat on the upstream side and the downstream side of the heater, but an element other than the thermopile (for example, a resistor) may be used.

The embodiments and modifications described above can be combined.

100, 100a, 100b, 100c ... Sensor package 1, 1a, 200, B1 ... Board 11, 11a, 201 ... Surface 112 ... Power supply terminal 113 ... Measurement terminal 12, 12a, 202 ...・ ・ Back surface 122, 122a, 122b, 122c, 203 ・ ・ ・ Land 2 ・ ・ ・ Flow sensor chip 21 ・ ・ ・ Main body 22 ・ ・ ・ Membrane 23 ・ ・ ・ Heater 231 ・ ・ ・ Power supply terminal 24, 241 242 ... Thermopile 243 ... Terminals to be measured 3, 3a ... Lid 31, 31a ... Vent holes 204 ... Solder 300 ... Waterproof / dustproof mesh 400 ... Wind direction adjustment member W1 ...・ Metal wire

Claims (5)

A flow sensor chip that has a sensor unit that detects the flow rate of fluid,
A case member having a hollow portion that opens toward the outside and accommodates the flow sensor chip.
A substrate having a through hole that covers the opening and communicates with the outside while mounting the flow sensor chip on the surface facing the opening.
A land provided on a surface of the substrate opposite to the surface on which the flow sensor chip is placed and connected by solder to a land provided on a second substrate having wiring for connecting electronic components is provided.
The land provided on the substrate, the land provided on the second substrate, the gap formed between the substrate and the second substrate by the solder, the through hole , and the hollow portion form the sensor portion. It is characterized by forming a flow path for guiding the fluid.
Package type flow sensor. A flow sensor chip that has a sensor unit that detects the flow rate of fluid,
A case member having a hollow portion that opens toward the outside and accommodates the flow sensor chip.
A substrate having a through hole that covers the opening and communicates with the outside while mounting the flow sensor chip on the surface facing the opening.
A land provided on a surface of the substrate opposite to the surface on which the flow sensor chip is placed and formed so as to surround the periphery of the through hole is provided.
A second board having wiring for connecting electronic components is connected to the land .
The second substrate is provided with a second through hole at a position corresponding to the area surrounded by the land.
The fluid is guided from a surface of the second substrate opposite to the surface to which the land is connected to the hollow portion through the second through hole and the through hole.
Package type flow sensor. The land is connected to the same surface as the surface to which the electronic component is connected in the second substrate.
The package type flow sensor according to claim 2 . On the surface of the second substrate opposite to the surface to which the land is connected , a filter member that prevents substances other than the fluid from entering the hollow portion covers the second through hole. Characterized by being provided,
The packaged flow sensor according to claim 2 or 3 . The second through hole is
A first opening that opens at a position corresponding to the area surrounded by the land,
A second opening that opens on the surface opposite to the surface to which the land is connected , and
It is characterized by including a flow path formed in the second substrate and guiding the fluid to the hollow portion by connecting the first opening and the second opening.
The package type flow sensor according to any one of claims 2 to 4 .

Images