JP6864163B1 - Pressure sensor device - Google Patents

Abstract

Provided is a pressure sensor device capable of preventing the adhesive layer for fixing the pedestal from peeling off without improving the processing accuracy of each component, and preventing unnecessary stress from being applied to the semiconductor pressure sensor element. .. The semiconductor pressure sensor element 17 provided with the diaphragm 26 and the pedestal 28 joins the mounting portion 29 provided around the diaphragm 26 of the pedestal 28 to the mounted wall portion 19 of the second case 5 with an adhesive. A gap g is positively formed between the outer peripheral portion 28Aa of the lower surface 28A of the pedestal 28 and the second annular surface S2.

Description

The present invention relates to a pressure sensor device that senses the pressure of a fluid by a diaphragm, and in particular, the adhesive layer for fixing the pedestal constituting the semiconductor pressure sensor element together with the diaphragm to the housing or case of the pressure sensor device does not peel off. Regarding pressure sensor device.

FIG. 5 is an exploded perspective view of the conventional semiconductor pressure sensor device shown in FIG. 1 of Japanese Patent No. 4281178 (Patent Document 1). Further, FIG. 6 is a cross-sectional view of the conventional semiconductor pressure sensor device shown in FIG. 2 of Japanese Patent No. 4281178 (Patent Document 1). In this conventional semiconductor pressure sensor device, a sensor case 20 in which a semiconductor pressure sensor element is arranged and resin-molded, and a sensor element that is insert-molded into the sensor case 20 so as to be partially exposed from the sensor case 20. It includes a lead 30 electrically connected to the sensor case 20, an outer case 40 that is assembled to the sensor case 20 and covers the sensor element, and an enclosure 42 that is formed in the outer case 40 and surrounds the exposed portion of the lead 30. The exposed portion of the lead 30 and the surrounding portion 42 form a connector portion capable of connecting the exposed portion of the lead 30 to an external terminal. The sensor case 20 and the outer case 40 are fitted by a sliding operation, and are prevented from coming off by an engaging structure (25, 47) provided between the sensor case 20 and the outer case 40. Further, the sensor case 20 is integrally provided with a pressure introduction port 21 into which the fluid to be measured flows.

As shown in FIG. 6, the sensor case 20 has an opening 20a in which a sensor element 10 or the like is arranged on one side thereof, and has a pressure introduction port 21 projecting from the bottom surface of the opening 20a to the opposite side. .. The tip of the pressure introduction port 21 can be attached to an appropriate position in the flow path of the water heater, for example, via an O-ring or the like. Inside the pressure introduction port 21, an introduction hole 22 for introducing the pressure from the flow path is provided.

A recess 23 recessed from the flat portion is formed on the bottom surface of the opening 20a in the sensor case 20, and the pedestal 11 of the sensor element 10 is fixed in the recess 23. Although not shown, the sensor element 10 has a configuration in which a plurality of diffusion resistors are formed on a diaphragm made of a semiconductor material having a piezoresistive effect (for example, single crystal silicon), and these diffusion resistors are bridge-connected. , The change in the resistance value of the diffusion resistance according to the deformation of this diaphragm is taken out as an electric signal from the bridge circuit.

The diaphragm of the sensor element 10 is adhered to the pedestal 11 by glass bonding or the like, and a through hole communicating with the introduction hole 22 is formed inside the pedestal 11. The pressure from the flow path is transmitted from the introduction hole 22 through the through hole of the pedestal 11 to the diaphragm of the sensor element 10. The pedestal 11 is joined to the bottom surface of the recess 23 via an adhesive layer. Further, the recess 23 is filled with a sealing agent 24 in order to improve the airtightness between the through hole of the pedestal 11 made of glass and the introduction hole 22.

Inside the opening 20a of the sensor case 20, a bipolar transistor element 12 as an amplifier circuit for amplifying an output signal from the sensor element 10, an adjustment for adjusting an output signal from the sensor element 10, a signal of the bipolar transistor element 12, and the like. The MOS transistor element 13 as a circuit is fixed by an adhesive.

The sensor element 10, the bipolar transistor element 12, the MOS transistor element 13, and the lead 30 are appropriately electrically connected to each other by a wire 14 formed by wire bonding. The electric signal (output) from the sensor element 10 is taken out from the exposed parts of the elements 12, 13 and the reed 30 and the reed through these wires 14.

Japanese Patent No. 4281178 FIGS. 1 and 2

In the semiconductor pressure sensor device of Patent Document 1, the pedestal 11 is joined to the bottom surface of the recess 23 via an adhesive layer, but the adhesive layer may be peeled off by the pressure of the fluid entering the through hole of the pedestal. There is.

A semiconductor pressure sensor element having a diaphragm portion on which a sensor circuit is formed, a tubular pedestal supporting the outer peripheral portion of the diaphragm portion, and the pressure of the fluid introduced into the internal passage of the pedestal through the fluid introduction path act. In a pressure sensor device having an electrically insulating case having a wall portion to be attached to which a semiconductor pressure sensor element is attached, the pedestal is formed to have an attachment portion around the semiconductor pressure sensor element. When the mounting portion is joined to the mounted wall portion of the case with an adhesive, it is possible to prevent the adhesive layer from peeling off. However, in order to realize such a configuration, it is necessary to improve the processing accuracy of each component in order to prevent unnecessary stress from being applied to the semiconductor pressure sensor element.

An object of the present invention is to prevent the adhesive layer for fixing the pedestal from peeling off without improving the processing accuracy of each component, and to prevent unnecessary stress from being applied to the semiconductor pressure sensor element. The purpose is to provide a pressure sensor device.

The present invention relates to a semiconductor pressure sensor element having a diaphragm portion on which a sensor circuit is formed, a tubular pedestal that supports the outer peripheral portion of the diaphragm portion, and a fluid introduced into an internal passage of the pedestal through a fluid introduction path. A pressure sensor device having an electrically insulating case having a wall portion to which a semiconductor pressure sensor element is mounted so that pressure acts is targeted for improvement.

In the present invention, the pedestal has a shape in which a mounting portion is provided around the semiconductor pressure sensor element. Then, the mounting portion of the pedestal is bonded to the mounted wall portion of the case with an adhesive. In addition, the case has a first annular surface that sandwiches an O-ring between it and an annular lower surface that surrounds the entrance of the pedestal's internal passage, and a lower surface of the pedestal that is located closer to the pedestal than the first annular surface. It is provided with a second annular surface facing the outer peripheral portion of the above. An O-ring is arranged in a compressed state between the first annular surface and the second annular surface. Then, a gap is created between the outer peripheral portion of the lower surface of the pedestal and the second annular surface so that the repulsive force of the compressed O-ring acts in the direction of pressing the mounting portion of the pedestal against the mounted wall portion of the case. It is formed.

According to the structure of the present invention, the pressure applied to the diaphragm from the fluid acts in the direction of pressing the mounting portion of the pedestal against the mounted wall portion of the case. As a result, according to the present invention, the repulsive force of the O-ring acts positively in the direction of pressing the mounting portion of the pedestal against the mounted wall portion of the case regardless of the pressure of the fluid. It is possible to prevent the layer of the material from peeling off. If a structure that does not create a gap between the outer peripheral portion of the lower surface of the pedestal and the second annular surface is adopted, if the machining accuracy of each part is low, the machining accuracy error causes stress unnecessary for the semiconductor pressure sensor. In addition, there arises a problem that the detection accuracy deteriorates. Even in such a case, according to the present invention, a gap is formed between the outer peripheral portion of the lower surface of the pedestal and the second annular surface, so that the gap and the deformation of the O-ring cause an error due to processing accuracy. It can absorb and prevent the generation of unnecessary stress.

In a specific structure, a processed semiconductor substrate in which a semiconductor pressure sensor element is formed in a central portion of the semiconductor substrate is joined to the upper surface of a pedestal. A first case portion having a fluid introduction path inside, a semiconductor pressure sensor element and a circuit board are housed, and a wall portion to be attached is provided, and a semiconductor pressure sensor element is housed between the first case part. The housing may be composed of a second case portion forming a space, a main body of the first case portion, and a third case portion for accommodating the second case portion. When this housing is adopted, the first case portion is formed concentrically with the fluid introduction path, and an annular recess is formed which accommodates the O-ring and has a first annular surface at the bottom, and is annular. It is preferable that a second annular surface is formed on the radial outer side of the opening of the recess. According to this structure, the positioning of the O-ring can be easily realized.

(A) to (D) are a plan view, a right side view, a bottom view, and a front view showing a pressure sensor device according to the first embodiment of the present invention. It is an exploded assembly view of the pressure sensor device shown in FIG. FIG. 3 is a sectional view taken along line III-III of FIG. 1 (C). It is an enlarged sectional view of the main part of FIG. It is an exploded perspective view which shows the structure of the conventional pressure sensor device. It is sectional drawing of the conventional pressure sensor device.

Hereinafter, embodiments of the pressure sensor device of the present invention will be described with reference to the drawings. 1 (A) to 1 (D) are a plan view, a right side view, a bottom view and a front view of the semiconductor pressure sensor device of the present embodiment, and FIG. 2 is an exploded assembly view of the pressure sensor device of FIG. Yes, FIG. 3 is a sectional view taken along line III-III of FIG. 1 (C), and FIG. 4 is a sectional view of a main part of FIG.

The pressure sensor device of the present embodiment includes a first case 1, a lead terminal 3, a second case 5 (FIGS. 2 and 3), and a third case 7. The same parts as those of the conventional structure are designated by the same reference numerals as those shown in FIGS. 5 and 6. In the first case 1, as shown in FIG. 2, an annular recess 9 is provided in the center of the upper surface of the rectangular parallelepiped main body 1A having a flat outer shape, and the pressure introduction port 21 projects downward from the lower surface. The introduction hole 22 inside the pressure introduction port 21 penetrates through the center of the bottom of the annular recess 9.

The second case 5 has a rectangular parallelepiped outer shape, and the lead terminal 3 is embedded and exposed from the front surface. An upper surface concave portion 15 and a lower surface concave portion 16 are provided on the upper and lower surfaces of the second case 5, respectively. The semiconductor pressure sensor element 17 is housed in the lower surface recessed portion 16, and the upper surface recessed portion 15 includes an integrated circuit 2 for processing the output signal of the semiconductor pressure sensor element 17, a power supply circuit, and a preparation circuit, and leads. A circuit board 18 that outputs an electric signal corresponding to a pressure value to the outside through the terminal 3 is housed. A part penetrates between the upper surface concave portion 15 and the lower surface concave portion 16, and a part of the upper surface of the lower surface concave portion 16 constitutes the mounted wall portion 19.

The first case 1, the second case 5, the third case 7, and the connector cover 4 are all made of synthetic resin having electrical insulation and flexibility, and are engaged and fixed to each other. The structure is formed at the corresponding position. The third case 7 has a rectangular parallelepiped shape with an open front surface, and the main body of the first case 1 and the second case 5 engaged with each other can be housed therein. The lead terminal 3 is covered with the connector cover 4 to form a connector.

As shown in FIG. 3, the semiconductor pressure sensor element 17 in the present embodiment includes a diaphragm 26 in which a sensor circuit is formed. The semiconductor pressure sensor element 17 is fixed to a tubular pedestal 28 that supports the outer peripheral portion of the diaphragm 26. The second case 5 is a semiconductor pressure sensor so that the pressure of the fluid introduced into the internal passage 32 of the pedestal 28 acts through the introduction hole 22 and the annular recess 9 which are the fluid introduction paths inside the first case 1. It has a wall portion 19 to be attached to which the element 17 is attached. The pedestal 28 has a shape in which a mounting portion 29 is provided around the semiconductor pressure sensor element 17. As will be described later, the mounting portion 29 of the present embodiment is composed of a part of the processed semiconductor substrate SS used for forming the semiconductor pressure sensor element 17.

The mounting portion 29 of the pedestal 28 is bonded to the mounted wall portion 19 of the second case 5 with an adhesive. The adhesive layer (not shown because it is thin) between the wall portion 19 to be attached and the attachment portion 29 extends substantially at right angles to the direction of the pressure received by the diaphragm 26. That is, the diaphragm 26 and the adhesive layer are in a substantially flush or parallel position and posture relationship. The pedestal 28 is made of a material having sufficient rigidity, corrosion resistance to a fluid, or the like, for example, glass.

In a more specific structure, a processed semiconductor substrate SS having a semiconductor pressure sensor element 17 formed in the center of the semiconductor substrate is joined to the upper surface of the pedestal 28. A groove 33 for separating the semiconductor pressure sensor element 17 and its peripheral portion is formed on the processed semiconductor substrate SS in a state of being joined to the pedestal 28. That is, the groove 33 separates the central diaphragm 26 from the peripheral portion. Further, this peripheral portion constitutes the mounting portion 29 of the pedestal 28. The groove 33 penetrates into the pedestal 28. In this way, it is possible to prevent the transfer of stress from the pedestal side 28 to the diaphragm 26.

As shown in FIG. 4, in the first case 1, the first annular surface S1 sandwiching the O-ring between the annular lower surface 28A surrounding the entrance portion of the internal passage 32 of the pedestal 28 and the first annular surface S1 and the first annular surface S1 sandwich the O-ring. A second annular surface S2 located closer to the pedestal 28 than the surface S1 and facing the outer peripheral portion of the lower surface 28A of the pedestal 28 is provided. The O-ring 27 is arranged in a compressed state between the first annular surface S1 and the second annular surface S2. Then, the repulsive force of the compressed O-ring 27 acts in the direction of pressing the mounting portion 29 of the pedestal 28 against the mounted wall portion 19 of the second case 5, so that the outer peripheral portion 28Aa of the lower surface 28A of the pedestal 28 acts. A gap g is formed between the second annular surface S2 and the second annular surface S2.

The presence of the O-ring 27 can prevent fluid from entering the surface side of the pedestal 28. The material of the O-ring 27 is also selected to have resistance to the fluid to be handled, and examples of the versatile material include silicone rubber.

According to the present embodiment, the repulsive force of the O-ring 27 positively acts in the direction of pressing the mounting portion 29 of the pedestal 28 against the mounted wall portion 19 of the second case, regardless of the pressure of the fluid. Therefore, it is possible to prevent the adhesive layer from peeling off. If a structure that does not generate a gap g between the outer peripheral portion 28Aa of the lower surface 28A of the pedestal 28 and the second annular surface S2 is adopted, if the machining accuracy of each part is low, the semiconductor pressure due to the error in the machining accuracy. Unnecessary stress is applied to the sensor 17, which causes a problem that the detection accuracy deteriorates. Even in such a case, according to the present embodiment, since the deformation of the O-ring 27 absorbs the error due to the processing accuracy, it is possible to prevent liquid leakage and generation of unnecessary stress.

In this embodiment, a first case 1 having a fluid introduction path composed of an introduction hole 22 and an annular recess 9 inside, a semiconductor pressure sensor element 17 and a circuit board 18 are housed, and a wall portion to be attached is accommodated. A second case 5 having a 19 and forming a storage space for accommodating the semiconductor pressure sensor element 17 with the first case 1, and a second case 5 for accommodating the main body of the first case 1 and the second case 5. The housing is composed of the case 7 of 3. Since such a housing is adopted, the first case 1 is formed concentrically with the fluid introduction path 22 to accommodate the O-ring 27 and to form an annular recess 9 having an annular surface 34 at the bottom. Therefore, the positioning of the O-ring 27 can be easily realized.

Next, the production method and operation of the present embodiment will be described. As shown in FIG. 2, in the pressure sensor device according to the first embodiment, the O-ring 27 is placed on the first annular surface S1 in the annular recess 9 of the first case 1, and further. The semiconductor pressure sensor element 17 is placed on the semiconductor pressure sensor element 17. Next, an adhesive is applied to the mounting portion 29 of the pedestal 28 of the semiconductor pressure sensor element 17, and then the lower surface of the second case 2 is recessed so that the mounted wall portion 19 of the second case 5 rests on it. In order to house the semiconductor pressure sensor element 17 in the portion 16, the first case 1 and the second case 5 are brought close to each other and fitted by a fitting structure. An adhesive may be applied to the mounting portion 29 of the pedestal 28 in advance, and the mounting portion 29 of the pedestal 28 may be adhered to the mounted wall portion 19 of the second case 5 with the adhesive. The elastic O-ring 27 is compressed and deformed between the first annular surface S1 and the lower surface 28A of the pedestal 28, and adheres to the first annular surface 34 and the bottom surface 28A of the pedestal 28 to leak fluid. While sealing so that there is no pedestal 28, the pedestal 28 is urged upward and the mounting portion 29 of the pedestal 28 is pressed in the direction toward the mounted wall portion 19 of the second case 5 to ensure the adhesion by the adhesive. To do. Further, in the present embodiment, the first case 1, the pedestal 28 and the second case 2 are arranged so as to positively form a gap g between the outer peripheral portion 28Aa of the lower surface 28A of the pedestal 28 and the second annular surface S2. Since the shape and dimensions of the case 5 are defined, the deformation of the O-ring 27 absorbs an error due to processing accuracy, and prevents liquid leakage and generation of unnecessary stress.

Next, when the necessary wiring is performed between the integrated circuit 2 and the circuit board 18 arranged in the upper surface recessed portion 15 of the second case 5, and the semiconductor pressure sensor element 17 and the lead terminal 3, the first case is obtained. The main body of 1 and the second case 5 are housed in the third case 7, and the connector cover 4 is fitted so as to cover the lead terminal 3, and the pressure sensor device is assembled.

In the pressure sensor device as described above, in the semiconductor pressure sensor element 17, when external pressure acts on the diaphragm 26 through the introduction hole 22, the annular recess 9, and the internal passage 32, the diaphragm 26 is deformed and the resistance value of the resistance element is changed. Is changed, and the change in resistance value is detected by a resistance bridge circuit (not shown), and a signal proportional to the pressure is output. The signal is processed by the integrated circuit 2 and output from the lead terminal 3 to the outside via the circuit board 18.

The measured fluid pressure acts on the diaphragm 26, but the pressure applied to the diaphragm 26 via the fluid acts in the direction of pressing the mounting portion 29 of the pedestal 28 against the mounted wall portion 19 of the second case 5. .. As a result, it is possible to prevent the adhesive layer from peeling off due to the pressure of the fluid.

According to the present invention, the pressure applied to the diaphragm from the fluid acts in the direction of pressing the mounting portion of the pedestal against the mounting wall portion of the case, so that the pressure of the fluid can prevent the adhesive layer from peeling off. In particular, according to the present invention, since a gap is formed between the outer peripheral portion of the lower surface of the pedestal and the second annular surface, the gap and the O-ring are deformed without improving the processing accuracy of each part. Can absorb errors due to machining accuracy and prevent unnecessary stress from being applied to the semiconductor pressure sensor element 17.

1 1st case 2 Integrated circuit 3 Lead terminal 4 Connector cover 5 2nd case 7 3rd case 9 Circular recess 15 Top concave recess 16 Bottom concave recess 17 Semiconductor pressure sensor element 18 Circuit board 19 Mounting wall 21 Pressure introduction port 22 Introduction hole 26 Diaphragm part 27 O-ring 28 Pedestal 29 Mounting part 32 Internal passage 33 Groove part S1 First annular surface S2 Second annular surface g Gap

Claims (2)

A semiconductor pressure sensor element having a diaphragm portion on which a sensor circuit is formed, and
A tubular pedestal that supports the outer peripheral portion of the diaphragm portion, and
A pressure sensor having an electrically insulating case having an attached wall portion to which the semiconductor pressure sensor element is attached so that the pressure of the fluid introduced into the internal passage of the pedestal through the fluid introduction path acts on the diaphragm portion. It ’s a device,
The pedestal has a shape in which a mounting portion is provided around the semiconductor pressure sensor element.
The mounting portion of the pedestal is bonded to the mounted wall portion of the case with an adhesive.
The case is located on the pedestal side of a first annular surface that sandwiches an O-ring between the pedestal and an annular lower surface that surrounds the entrance of the internal passage, and the first annular surface. It is provided with a second annular surface facing the outer peripheral portion of the lower surface of the pedestal.
The O-ring is arranged in a compressed state between the first annular surface and the second annular surface.
The outer peripheral portion of the lower surface of the pedestal and the second annular surface so that the compressed repulsive force of the O-ring presses the mounting portion of the pedestal against the mounted wall portion of the case. A semiconductor pressure sensor device characterized in that a gap is formed between them. A first case portion having the fluid introduction path inside, and
A second case portion that houses the semiconductor pressure sensor element and the circuit board, includes the mounting wall portion, and forms a storage space for accommodating the semiconductor pressure sensor element between the first case portion and the second case portion.
It has a housing composed of a main body of the first case portion and a third case portion for accommodating the second case portion.
The first case portion is formed concentrically with the fluid introduction path to accommodate the O-ring, and an annular recess having the first annular surface is formed at the bottom thereof, and the annular recess is formed. The semiconductor pressure sensor device according to claim 1, wherein the second annular surface is formed on the radial outer side of the opening.

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