JP2569863B2 - Semiconductor pressure sensor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a semiconductor pressure sensor.

[Conventional technology and problems]

2. Description of the Related Art Conventionally, there is a so-called relative pressure detection type semiconductor pressure sensor that measures a pressure difference between an atmospheric pressure and a medium to be measured. In this sensor, it is necessary to provide a special air introduction hole for introducing air into the sensor housing, and there is a problem that special consideration must be given to intrusion of water or the like. That is, when an air passage is provided in the sensor housing and a filter that allows only air to pass through the passage is inserted, there is a problem that measurement cannot be performed if the filter is clogged.

An object of the present invention is to provide a semiconductor pressure sensor that can secure an air introduction passage through which air can be reliably introduced.

[Means for solving the problem]

According to a first aspect of the present invention, there is provided a housing having a chip storage chamber formed therein, a lid member provided at an opening of the chip storage chamber of the housing, and a lid member disposed on an upper surface of the lid member. A filler for filling the gap, a semiconductor chip having a diaphragm with a semiconductor strain gauge, which is hermetically bonded to the inner wall of the chip storage chamber of the housing, and to which pressure of a medium to be measured is applied through a pressure introduction hole of the housing; A grommet fixed to the housing and connected in a hermetically sealed state with a cord in which the stranded wire is covered with insulating material,
The gist of the present invention is a semiconductor pressure sensor having a lower end opening through the lid member to the chip storage chamber of the housing and an upper end protruding from an upper surface of the filler and an air introduction pipe communicating with the cord. .

According to a second aspect of the present invention, there is provided a housing in which a chip storage chamber is formed, a lid member provided in an opening of the chip storage chamber of the housing, and a lid member disposed on an upper surface of the lid member. A filler for filling the gap, a semiconductor chip having a diaphragm with a semiconductor strain gauge, which is hermetically bonded to the inner wall of the chip storage chamber of the housing, and to which pressure of a medium to be measured is applied through a pressure introduction hole of the housing; Atmosphere introduction that connects the cord fixed to the housing and covered with an insulating material with a stranded wire in an airtight state, communicates with the cord, and penetrates the lid material and opens to the chip storage chamber of the housing. The gist of the present invention is a semiconductor pressure sensor including a grommet having a pipe portion for use.

[Action]

In the first invention, the atmosphere is guided to the atmosphere introduction pipe through the gap in the stranded wire in the cord, and is applied to the diaphragm of the semiconductor chip. At this time, the gap between the lid member and the housing is filled with the filler, and the intrusion of moisture, dust, and the like from the outside is prevented. Further, since the upper end of the air introduction pipe protrudes from the upper surface of the filler, the air introduction pipe is not blocked by the filler.

In the second invention, the air is guided from the inside of the air introduction pipe portion of the grommet through the gap in the stranded wire in the cord, and is applied to the diaphragm of the semiconductor chip. At this time, the gap between the lid member and the housing is filled with the filler, and the intrusion of moisture, dust, and the like from the outside is prevented.

First Embodiment An embodiment of the present invention will be described below with reference to the drawings.

The semiconductor pressure sensor of the present embodiment is a sensor for measuring a refrigerant pressure in a vehicle cooling device. FIG. 1 shows a cross section of the sensor of this embodiment.

The iron housing 1 is formed in a cylindrical shape with a bottom, and the inside thereof is a chip storage chamber R. A small diameter screw portion 2 is formed on the bottom surface of the housing 1. A two-sided width 3 for fastening is cut out on the outer peripheral surface of the housing 1. The screw portion 2 of the housing 1 is screwed into the refrigerant pipe 4, and the present sensor is attached to the refrigerant pipe 4.

A recess 5 is formed in the center of the bottom surface of the chip storage chamber R of the housing 1, and a low melting glass 6 is formed in the recess 5.
Thereby, the glass pedestal 7 is hermetically bonded. A semiconductor chip 8 is hermetically bonded to the upper surface of the glass pedestal 7 by an anodic bonding method. A diaphragm is formed on the semiconductor chip 8, and a semiconductor strain gauge is arranged on the diaphragm. The refrigerant pressure is applied to the diaphragm through the pressure introduction hole 9 of the housing 1 and the pressure introduction hole 10 of the glass pedestal 7. Further, a signal amplifying circuit is formed on the semiconductor chip 8, and the circuit amplifies the output by the semiconductor strain gauge.

A shield plate 11 made of an iron plate as a cover member for preventing electromagnetic wave intrusion is press-fitted into an opening on the upper surface of the housing 1. A lead pin support member 12 made of an insulating material such as nylon is fixed to the bottom surface of the chip storage chamber R of the housing 1, and an L-shaped lead pin 13 is supported by the lead pin support member 12. Further, the lead pins 13 are electrically connected to the amplifier circuit of the semiconductor chip 8 by bonding wires 14. The standing portion of the lead pin 13 passes through the shield plate 11 via the feedthrough capacitor 15.

Further, an iron air introduction pipe 16 is erected on the shield plate 11 in a sealed state by welding, and its lower end is opened to the chip storage chamber R below the shield plate 11. Further, the lead pin 13 in the chip storage chamber R is provided with a capacitor 17 for removing ignition noise and the like. The chip housing chamber R is filled with a gel resin 18 made of silicon gel, and the horizontal portion of the lead pin 13, the semiconductor chip 8, and the bonding wire 14 are connected to the gel resin 18.
, So that these members 8, 13, and 14 do not come into contact with the atmosphere.

A rubber grommet 19 is fixed to the upper surface of the housing 1, and a cord (insulated wire) 20 is connected to the grommet 19 in an airtight state. The cord 20 is formed by covering a stranded wire with an insulating material, a cavity is formed in the stranded wire, and the cavity serves as an air introduction passage. This code
The other end of 20 is open at a position separated from the semiconductor pressure sensor. The stranded wire of the cord 20 is exposed in the inner chamber 21 of the grommet 19, and this exposed portion is connected to one end of the lead pin 22 by crimping. The other end of the lead pin 22 is connected to the lead pin 13 by welding.

The upper surface of the shield plate 11 is filled with a filler 23 made of epoxy resin, and the filler 23 fills a gap between the shield plate 11 and the housing 1. or,
The weld between the lead pin 13 and the lead pin 22 is located in the filler 23. The filler 23 is injected twice from a filler inlet 24 formed in the grommet 19.

In this state, the upper end of the atmosphere introduction pipe 16 protrudes above the upper surface of the filler 23 and opens to the internal chamber 21.

Next, the operation of the semiconductor pressure sensor thus configured will be described.

First, at the time of assembling the sensor, the glass pedestal 7 in which the semiconductor chip 8 is joined in the concave portion 5 of the housing 1 is joined with the low-melting glass 6, and then the lead pin support member 12 is attached to the chip storage chamber R of the housing 1. Attach to the bottom of. Next, the gel-like resin 18 is filled in the chip storage chamber R of the housing 1, and the shield plate 11 to which the air introduction pipe 16 is fixed is pressed into the housing 1. And
Attach feed-through capacitor 15.

Thereafter, the grommet 19 to which the cord 20 is connected is fixed to the housing 1, the lead pin 22 and the lead pin 13 are welded, and the filler 23 is injected from the filler inlet 24 of the grommet 19. The first injection of the filler 23 causes the grommet 19
The area excluding the inner chamber 21 of the shield plate 11 is filled.
The gap between the housing and the housing 1 is filled. Further, the filler injection port 24 is filled by the second injection of the filler 23.

Then, at the time of pressure measurement, the atmosphere is guided to the internal chamber 21 of the grommet 19 in the hollow inside the stranded wire in the cord 20, and furthermore, the chip storage chamber R becomes atmospheric pressure through the air introduction pipe 16. . In this state, a high-pressure refrigerant passes through the refrigerant pipe member 4 by driving the cooling device. This refrigerant pressure is applied to the pressure introducing hole 9 of the housing 1 and the pressure introducing hole 10 of the glass pedestal 7.
, And propagates to the diaphragm of the semiconductor chip 8, the diaphragm is deformed by the differential pressure between the atmospheric pressure and the refrigerant pressure, and the resistance value changes due to the piezoresistance effect of the semiconductor strain gauge.
This change in the resistance value is converted into an electric signal, and this signal is amplified by the amplifier circuit, and the bonding wire 14, the lead pin
13. The lead pin 22 is taken out of the sensor via the stranded wire of the cord 20.

As described above, in the present embodiment, the housing 1 having the chip storage chamber R, the shield plate 11 (cover material) provided at the opening of the chip storage chamber R of the housing 1, and the upper surface of the shield plate 11 are provided. , Shield plate
Filler 23 for filling the gap between 11 and housing 1
And a semiconductor chip 8 having a diaphragm with a semiconductor strain cage, which is hermetically bonded to the inner wall of the chip storage chamber R of the housing 1 and to which the refrigerant pressure is applied through the pressure introducing hole 9 of the housing 1, and a stranded wire fixed to the housing 1. A grommet 19 to which a cord 20 coated with an insulating material is connected in an airtight state, and a lower end penetrating through the shield plate 11 and opening in the chip storage chamber R of the housing 1, and an upper end protruding from an upper surface of the filler 23. Thus, an air introduction pipe 16 communicating with the cord 20 was provided.

Therefore, the atmosphere is guided to the atmosphere introduction pipe 16 through the gap in the stranded wire in the cord 20 and is applied to the diaphragm of the semiconductor chip 8. At this time, the shield plate is
The gap between the housing 11 and the housing 11 is filled, so that intrusion of moisture, dust and the like from the outside can be prevented. Further, since the upper end of the air introduction pipe 16 protrudes from the upper surface of the filler 23, the air introduction pipe 16 is not blocked by the filler 23. As a result, it is possible to secure an atmosphere introduction passage through which the atmosphere can be reliably introduced.

Also, since the air is guided through the gap in the stranded wire in the cord 20, there is no need to provide a special air introduction hole and a filter for preventing intrusion of water, dust, oil, etc.
Cost reduction can be achieved.

As an application example of this embodiment, for example, as shown in FIG. 2, the signal extraction unit may be a direct coupler. That is, the terminal pin 25 is inserted and supported in the grommet 19, and the coupler case 27 in which the connection terminal 26 and the cord 20 are connected in advance is connected to the grommet 19. Then, the atmosphere may be introduced from the cord 20 to the atmosphere introduction pipe 16 through the communication hole 28.

Second Embodiment Next, a second embodiment corresponding to the second invention will be described.

FIG. 3 shows a cross section of the semiconductor pressure sensor of this embodiment. In the semiconductor pressure sensor of this embodiment, the housing 1a and the housing 1b are fixed by caulking, and the air is introduced by the air introducing pipe 33 of the grommet 29.
The same members as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

The cord 20 is connected to the grommet 29 in an airtight state, and a crimp terminal 31 is connected to a stranded wire of the cord 20 at an end of the cord 20, and the crimp terminal 31 is connected to the filler injection chamber 32 of the housing 1b. It is protruding. Also, grommet
An air introduction pipe portion 33 having an air introduction hole 30 is formed in 29, and one end of the air introduction hole 30 communicates with an end of the cord 20. On the other hand, a shield plate 11 as a cover material is disposed at an upper opening of the chip storage chamber R of the housing 1a via a sealing O-ring 34, and the air introduction pipe 33 of the grommet 29 is sealed in the shield plate 11. The lower end of the pipe 33 for air introduction is opened in the chip storage chamber R. At this time, the inclined portion 11 of the shield plate 11
A triangular seal is formed between a, the inner wall of the housing 1a, and the bottom surface of the housing 1b.

Further, a circuit board 35 having an amplifier circuit is provided in the chip storage chamber R, and lead pins 36 from the circuit board 35 penetrate the shield plate 11 via the penetrating capacitor 15 and protrude into the filler filling chamber 32 of the housing 1b. ing. In the filling material injection chamber 32, the lead pin 36 and the crimp terminal 31 are welded, and the inside of the filling material injection chamber 32 is filled with the filler 23. At this time, a sealing ring 37 is interposed between the outer peripheral portion of the crimp terminal 31 and the grommet 29, and the sealing ring 37 prevents the filler 23 from entering.
Further, the chip storage chamber R is filled with a gel resin 18 so that the semiconductor chip 8, the bonding wires 14, and the circuit board 35 do not come into contact with the atmosphere.

At the time of pressure measurement, the atmosphere is guided through the air introduction pipe part 33 of the grommet 29 through the hollow space in the twisted wire in the cord 20, and the chip storage chamber R is brought to the atmospheric pressure. In this state, the refrigerant pressure propagates through the pressure introducing hole 9 of the housing 1 and the pressure introducing hole 10 of the glass pedestal 7 to the diaphragm of the semiconductor chip 8, and the diaphragm is deformed by the differential pressure between the atmospheric pressure and the refrigerant pressure. The resistance value changes due to the piezoresistance effect of the semiconductor strain gauge. This change in the resistance value is converted into an electric signal, and this signal is transmitted to the circuit board via the bonding wire 14.
Amplified by 35 amplifier circuits, lead pin 36, crimp terminal 3
1. It is taken out of the sensor via the stranded wire of the cord 20.

As described above, in this embodiment, the housings 1a and 1b having the chip storage chambers R, and the shield plates 11 (covers) provided at the openings of the chip storage chambers R of the housings 1a and 1b.
And a filler 23 arranged on the upper surface of the shield plate 11 for filling a gap between the shield plate 11 and the housings 1a and 1b, and airtightly bonded to the inner wall of the chip storage chamber R of the housings 1a and 1b. The semiconductor chip 8 having a diaphragm with a semiconductor strain gauge to which the pressure of the refrigerant is applied through the pressure introduction hole 9 of the above, and the cord 20 fixed to the housings 1a and 1b and covered with a stranded wire by an insulating material are connected in an airtight state. At the same time, a grommet 29 having an air introduction pipe portion 33 communicating with the cord 20 and passing through the shield plate 11 and opening to the chip storage chamber R of the housings 1a and 1b is provided.

As a result, it is possible to secure an atmosphere introduction passage through which the atmosphere can be reliably introduced.

Further, in this embodiment, the refrigerant is used as the pressure medium, but it is needless to say that various kinds of oil, water and the like can be used.

〔The invention's effect〕

As described above in detail, according to the present invention, an excellent effect that an air introduction passage through which the air can be reliably introduced can be ensured.

[Brief description of the drawings]

FIG. 1 is a sectional view of a semiconductor pressure sensor according to a first embodiment, and FIG.
The figure is a sectional view of a semiconductor pressure sensor of an application example of the first embodiment,
FIG. 3 is a sectional view of a semiconductor pressure sensor according to a second embodiment. 1 is a housing, 8 is a semiconductor chip, 9 is a pressure introducing hole,
11 is a shield plate as a lid material, 16 is an air introduction pipe,
19 is a grommet, 20 is a cord, 23 is a filler, 29 is a grommet, 33 is a pipe for introducing air, and R is a chip storage room.

Claims (2)

(57) [Claims] A housing having a chip storage chamber formed therein; a lid provided at an opening of the chip storage chamber of the housing; a gap disposed between the lid and the housing disposed on an upper surface of the lid. And a sealing material for airtightly bonding to an inner wall of the chip storage chamber of the housing,
A grommet in which a semiconductor chip having a diaphragm with a semiconductor strain gauge to which a pressure of a medium to be measured is applied through a pressure introduction hole of a housing and a cord fixed to the housing and having a stranded wire covered with an insulating material connected in an airtight state. A semiconductor pressure, comprising: a lower end that penetrates the lid member and opens into a chip storage chamber of the housing, and an upper end protrudes from an upper surface of the filler and communicates with the cord. Sensor. 2. A housing having a chip storage chamber formed therein, a lid member provided at an opening of the chip storage chamber of the housing, and a gap between the lid member and the housing disposed on an upper surface of the lid member. And a sealing material for airtightly bonding to an inner wall of the chip storage chamber of the housing,
A semiconductor chip having a diaphragm with a semiconductor strain gauge to which the pressure of the medium to be measured is applied through a pressure introduction hole of the housing, and a cord fixed to the housing and covered with a stranded wire covered with an insulating material, in a hermetically connected state. A grommet communicating with the cord and having a pipe portion for introducing air into the chip storage chamber of the housing that penetrates through the lid member.