JP7252956B2 - pressure sensor device - Google Patents

Description

The present invention relates to a pressure sensor device that senses the pressure of a fluid with a diaphragm, and in particular, an adhesive layer for fixing a pedestal constituting a semiconductor pressure sensor element together with a diaphragm to a housing or case of the pressure sensor device without peeling off. It relates to a 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). FIG. 6 is a sectional view of the conventional semiconductor pressure sensor device shown in FIG. 2 of Japanese Patent No. 4281178 (Patent Document 1). This conventional semiconductor pressure sensor device comprises a resin-molded sensor case 20 in which a semiconductor pressure sensor element is disposed, and a sensor element which is insert-molded into the sensor case 20 so that a part of the sensor case 20 is exposed. an outer case 40 assembled to the sensor case 20 to cover the sensor element; and an enclosing portion 42 formed in the outer case 40 to enclose the exposed portion of the lead 30. The exposed portion of the lead 30 and the enclosing portion 42 constitute 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 together by a sliding motion, and the engaging structures (25, 47) provided between the sensor case 20 and the outer case 40 prevent them from coming off. 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 the sensor element 10 and the like are arranged on one side, and a pressure introduction port 21 protruding from the bottom of the opening 20a to the opposite side. . The tip of the pressure introduction port 21 can be attached to a suitable location in the flow path of the water heater, for example, via an O-ring or the like. An introduction hole 22 is provided inside the pressure introduction port 21 for introducing pressure from the flow path.

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

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

In the opening 20a of the sensor case 20, a bipolar transistor element 12 as an amplifier circuit for amplifying the output signal from the sensor element 10, an adjustment for adjusting the output signal from the sensor element 10 and the signal from the bipolar transistor element 12, etc. A MOS transistor element 13 as a circuit is fixed with an adhesive.

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

Japanese Patent No. 4281178 Figures 1 and 2

In the semiconductor pressure sensor device of Patent Document 1, the pedestal 11 is bonded to the bottom surface of the recess 23 via an adhesive layer. be. Especially when the fluid melts the adhesive, the possibility of peeling off the adhesive layer increases.

SUMMARY OF THE INVENTION An object of the present invention is to provide a pressure sensor device in which an adhesive layer for fixing a pedestal does not come off.

The present invention comprises a semiconductor pressure sensor element having a diaphragm portion in which a sensor circuit is formed, a cylindrical pedestal supporting the outer peripheral portion of the diaphragm portion, and a fluid introduced into an internal passage of the pedestal through a fluid introduction passage. An object of improvement is a pressure sensor device provided with an electrically insulating case having a mounted wall portion to which a semiconductor pressure sensor element is mounted so that a pressure acts thereon. In the present invention, the pedestal has a shape with a mounting portion 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.

According to the structure of the present invention, the pressure applied to the diaphragm from the fluid acts in the direction of pressing the attachment portion of the pedestal against the attached wall portion of the case. As a result, it is possible to prevent the adhesive layer from peeling off due to the pressure of the fluid.

In a specific structure, a processed semiconductor substrate having a semiconductor pressure sensor element formed in the central portion of the semiconductor substrate is bonded to the upper surface of the pedestal. A groove is formed in the processed semiconductor substrate bonded to the pedestal to separate the semiconductor pressure sensor element from its surrounding portion. Further, the peripheral portion constitutes a mounting portion for the pedestal. This groove prevents the stress applied to the mounting portion of the pedestal from being transmitted to the semiconductor pressure sensor element. Therefore, the pressure detection accuracy is not degraded even when the adhesive is used for attachment.

In addition, it is preferable that the groove part enters into the inside of the pedestal. By doing so, the transmission of stress can be prevented more reliably.

It is preferable that an annular surface sandwiching an O-ring is formed inside the fluid introduction path of the case and an annular lower surface surrounding the inlet of the internal passage of the pedestal. The presence of the O-ring can prevent fluid from entering the surface side of the pedestal.

A housing for housing the semiconductor pressure sensor element between the first case portion having the fluid introduction path therein and a mounting wall portion for housing the semiconductor pressure sensor element and the circuit board and for housing the semiconductor pressure sensor element. The housing may be composed of a second case portion forming the space and a third case portion accommodating the main body of the first case portion and the second case portion. When this housing is employed, the first case portion is formed concentrically with the fluid introduction path, and is formed with an annular recess that accommodates the O-ring and has the annular surface at the bottom. preferable. With this structure, the positioning of the O-ring can be easily achieved.

1A to 1D are a plan view, a right side view, a bottom view and a front view showing the pressure sensor device according to the first embodiment of the present invention; FIG. FIG. 2 is an exploded view of the pressure sensor device shown in FIG. 1; FIG. 1C is a cross-sectional view taken along the line III-III of FIG. 1(C); FIG. 5 is a cross-sectional view of a pressure sensor device according to a second embodiment of the invention; 1 is an exploded perspective view showing the configuration of a conventional pressure sensor device; FIG. 1 is a cross-sectional view of a conventional pressure sensor device; FIG.

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

The pressure sensor device of the first embodiment includes a first case 1, lead terminals 3, a second case 5 (FIGS. 2 and 3), and a third case 7. As shown in FIG. The same reference numerals as those in FIGS. 5 and 6 are assigned to portions similar to those of the conventional structure. As shown in FIG. 2, the first case 1 has an annular concave portion 9 in the center of the upper surface of a rectangular parallelepiped main body 1A having a flat outer shape, and a pressure introduction port 21 protrudes downward from the lower surface. An 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, in which the lead terminals 3 are embedded and exposed from the front surface. An upper recessed portion 15 and a lower recessed portion 16 are provided on the upper and lower surfaces of the second case 5, respectively. A semiconductor pressure sensor element 17 is accommodated in the lower surface recessed portion 16, and an integrated circuit 2 for processing the output signal of the semiconductor pressure sensor element 17, a power supply circuit and a conditioning circuit are contained in the upper surface recessed portion 15. A circuit board 18 for outputting an electric signal corresponding to the pressure value to the outside through the terminal 3 is accommodated. A portion of the upper surface recessed portion 15 and the lower surface recessed portion 16 is partially penetrated, and a portion of the upper surface of the lower surface recessed portion 16 constitutes a 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 fixed by engaging with each other. Structures are formed at corresponding locations. The third case 7 has a rectangular parallelepiped shape with an open front surface, and can house therein the main body of the first case 1 and the second case 5 which are engaged with each other. The lead terminal 3 is covered with a connector cover 4 to form a connector.

As shown in FIG. 3, the semiconductor pressure sensor element 17 in this embodiment has a diaphragm 26 on which a sensor circuit is formed. The semiconductor pressure sensor element 17 is fixed to a cylindrical 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 through the introduction hole 22 and the cylindrical recess 9, which are fluid introduction paths inside the first case 1, acts. It has an attached wall portion 19 to which the sensor element 17 is attached. The pedestal 28 has a shape having a mounting portion 29 around the semiconductor pressure sensor element 17 . As will be described later, the mounting portion 29 of the present embodiment is made up of part of the processed semiconductor substrate SS used to form the semiconductor pressure sensor element 17 .

The mounting portion 29 of the pedestal 28 is joined to the mounted wall portion 19 of the second case 5 with an adhesive that does not melt with fluid. The adhesive layer (not shown due to its thin thickness) between the attached wall portion 19 and the attachment portion 29 extends substantially perpendicular to the direction of pressure applied to the diaphragm 26 . That is, the diaphragm 26 and the adhesive layer are substantially flush or parallel in position and attitude.

The adhesive that does not dissolve in a fluid is, for example, a material that is substantially insoluble in water if the fluid is aqueous, a material that is substantially insoluble in organic matter if the fluid is an organic solution, or a material in which the fluid is In the case of an acid or alkaline solution, it means a material that is substantially unaffected by this. Depending on the properties, temperature, pH and pressure range of the fluid to be measured, solubility, acid/alkaline resistance, and heat resistance An appropriate adhesive is selected in consideration of properties, chemical resistance, and the like.

The pedestal 28 is made of a material having sufficient rigidity and corrosion resistance to fluids, such as glass. Of course, it must be one that exhibits performance.

In a more specific structure, a processed semiconductor substrate SS having a semiconductor pressure sensor element 17 formed in the central portion of the semiconductor substrate is bonded to the upper surface of the pedestal 28 . A groove portion 33 is formed in the processed semiconductor substrate SS bonded to the pedestal 28 to separate the semiconductor pressure sensor element 17 from its surrounding portion. That is, the grooves 33 extend in four straight lines that divide the rectangular upper surface of the semiconductor pressure sensor element 17 in a grid pattern, and the central diaphragm 26 is separated from the surrounding portion by the four grooves 33 . Further, the peripheral portion constitutes a mounting portion 29 for the pedestal 28 . The groove portion 33 prevents stress applied to the mounting portion 29 of the base 28 from being transmitted to the semiconductor pressure sensor element 17 . Therefore, the pressure detection accuracy is not degraded even when the adhesive is used for attachment.

Note that the groove portion 33 extends into the pedestal 28 . By doing so, the transmission of stress can be prevented more reliably.

An annular surface 34 that sandwiches the O-ring 27 is formed inside the annular concave portion 9 that constitutes the fluid introduction path of the first case 1 and the annular lower surface that surrounds the inlet portion of the internal passage 32 of the pedestal 28 . ing. The presence of the O-ring 27 can prevent fluid from entering the surface side of the pedestal 28 . The O-ring 27 has elasticity and is formed to have a thickness slightly larger than the depth of the annular recess 9, so that when the first case 1 and the second case 5 are assembled, the pedestal 28 will not move. and the annular surface 34 to seal the fluid. The material of the O-ring 27 is also selected to be resistant to the fluid to be handled, and silicone rubber is an example of a versatile material.

In this embodiment, the first case 1 having therein a fluid introduction path composed of the introduction hole 22 and the annular concave portion 9, the semiconductor pressure sensor element 17 and the circuit board 18 are accommodated, and the wall portion to be mounted is provided. 19, a second case 5 forming a storage space for storing the semiconductor pressure sensor element 17 between itself and the first case 1; A case 7 of 3 constitutes a housing. Since such a housing is adopted, the first case 1 is formed with an annular recess 9 which is formed concentrically with the fluid introduction path, accommodates the O-ring 27 and has an annular surface 34 at the bottom. , and the positioning of the O-ring 27 can be easily realized.

Next, operation of the first embodiment will be described. As shown in FIG. 2, in the pressure sensor device according to the first embodiment, an O-ring 27 is placed on the annular surface 34 in the annular recess 9 of the first case 1, and a semiconductor device is placed thereon. A pressure sensor element 17 is placed. 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 thereon. In order to accommodate the semiconductor pressure sensor element 17 in the portion 16, the first case 1 and the second case 5 are brought closer to each other and are fitted by a fitting structure. At this time, the flexible O-ring 27 receives stress between the annular surface 34 and the bottom surface of the pedestal 28, is deformed, and adheres tightly to the annular surface 34 and the bottom surface of the pedestal 28 to prevent fluid leakage. At the same time, the semiconductor pressure sensor element 19 is urged upward to press the mounting portion 29 of the pedestal 28 toward the mounted wall portion 19 of the second case 5, thereby ensuring adhesion with the adhesive. to

Next, after necessary wiring is performed between the integrated circuit 2 and the circuit board 18, and between the semiconductor pressure sensor element 17 and the lead terminals 3, which are arranged in the recessed portion 15 of the upper surface of the second case 5, the first case is completed. The first main body 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 terminals 3 to assemble the pressure sensor device.

In the pressure sensor device as described above, when external pressure is applied to 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 increases. The change in resistance is sensed by a resistance bridge circuit (not shown) to output a signal proportional to pressure. The signal is processed by the integrated circuit 2 and output from the lead terminal 3 through the circuit board 18 to the outside.

The pressure of the fluid to be measured acts on the diaphragm 26, and the pressure applied to the diaphragm 26 via the fluid acts in the direction of pressing the attachment portion 29 of the base 28 against the attached 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.

FIG. 4 shows a cross-sectional view of a vehicle-mounted pressure sensor device according to a second embodiment of the present invention, which is in the middle of manufacturing. This pressure sensor device comprises a semiconductor pressure sensor element 37 having a diaphragm 35 in which a sensor circuit is formed; An element case 43 having an electrically insulating property and having a mounted wall portion 41 on which a semiconductor pressure sensor element 37 is mounted so as to act on the pressure of fluid introduced into the element case 43 is provided.

The pedestal 36 has a shape with a mounting portion 44 around the diaphragm 35 . The mounting portion 44 of the pedestal 36 is bonded to the mounted wall portion 41 of the element case 43 with an adhesive that does not melt with fluid.

The element case 43 is sandwiched and fixed between a female case 45 having a fluid introduction path 38 and a male case 47 from which a lead terminal 46 protrudes. An O -ring 48 is arranged between the outer peripheral surface of the element case 43 and the inner peripheral surface of the female case 45 . This O -ring 48 prevents fluid from entering the male case 47 .

In this embodiment, the female case 45 and the male case 47 are integrated by crimping the crimped portion 46 of the female case 45 toward the shoulder portion of the male case 47 .

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 mounted wall portion of the case, thereby preventing the adhesive layer from peeling off due to the pressure of the fluid.

REFERENCE SIGNS LIST 1 first case 2 integrated circuit 3 lead terminal 4 connector cover 5 second case 7 third case 9 cylindrical concave portion 15 upper concave portion 16 lower concave portion 17 semiconductor pressure sensor element 18 circuit board 19 mounted wall portion 21 Pressure introduction port 22 Introduction hole 26 Diaphragm part 27 O-ring 28 Pedestal 29 Mounting part 32 Internal passage 33 Groove 34 Annular surface 35 Diaphragm 36 Pedestal 37 Semiconductor pressure sensor element 38 Fluid introduction path 39 Internal passage 41 Attached wall part 43 Element Case 44 Mounting part 45 Female case 46 Lead terminal 47 Male case

Claims (4)

a semiconductor pressure sensor element having a diaphragm portion in which a sensor circuit is formed;
a cylindrical pedestal that supports the outer peripheral portion of the diaphragm;
A pressure sensor device comprising an electrically insulating case having a mounted wall portion on which the semiconductor pressure sensor element is mounted so that the pressure of the fluid introduced into the internal passage of the base through the fluid introduction passage acts on the pressure sensor device, ,
The pedestal has a shape with a mounting portion 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 ;
A processed semiconductor substrate having the semiconductor pressure sensor element formed in the center of the semiconductor substrate is bonded to the upper surface of the pedestal,
The processed semiconductor substrate bonded to the pedestal is formed with a groove for separating the semiconductor pressure sensor element from its surrounding portion,
The semiconductor pressure sensor device , wherein the peripheral portion constitutes the mounting portion of the base . 2. The semiconductor pressure sensor device according to claim 1 , wherein said groove extends into said base. 2. The semiconductor pressure device according to claim 1, wherein the inside of the fluid introduction path of the case is formed with an annular surface that sandwiches an O-ring between the annular lower surface of the pedestal and the annular lower surface surrounding the inlet of the internal passage. sensor device. a first case portion having the fluid introduction path therein;
a second case portion that accommodates the semiconductor pressure sensor element and the circuit board, has the attached wall portion, and forms a storage space that accommodates the semiconductor pressure sensor element between itself and the first case portion;
a housing composed of a main body of the first case portion and a third case portion that houses the second case portion;
4. The first case part according to claim 3 , wherein an annular recess is formed concentrically with the fluid introduction path, accommodates the O-ring, and has the annular surface at the bottom. Semiconductor pressure sensor device.

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