JP2000249614A - Semiconductor sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor sensor capable of detecting high pressure. SOLUTION: A semiconductor pressure sensor is provided with a pressure introducing opening 2 for introducing the pressure of a medium to be measured at a pressure introducing member 3, is provided with a semiconductor and a base plate 6 directly or indirectly provided with the semiconductor, and receives the pressure of the medium to be measured introduced from the pressure introducing opening 2 to detect the pressure of the medium to be measured by the semiconductor. As the base plate 6 is airtightly connected to the pressure introducing member 3 so that the semiconductor may face the pressure introducing opening 2, it is possible to detect the high pressure of the medium to be measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor pressure sensor for detecting the pressure of a medium to be measured using a semiconductor.

[0002]

2. Description of the Related Art As a semiconductor pressure sensor for detecting the pressure of a medium to be measured composed of liquid, gas, etc.
Japanese Unexamined Patent Publication No. -273332 discloses an example. The semiconductor pressure sensor includes a metal housing having a pressure introducing hole for introducing the pressure of a medium to be measured, a semiconductor chip disposed on a glass pedestal inside the housing so as to face the pressure introducing hole, And a circuit board provided around the chip and electrically connected to the semiconductor chip by wire bonding.

An amplifying circuit for amplifying a signal detected by the semiconductor chip is formed on the circuit board. Above the circuit board, an amplifier for removing noise to the semiconductor chip and the circuit board is provided. A feedthrough capacitor is provided, and the detection signal amplified by the circuit board is output to the outside via a terminal.

[0004] The semiconductor chip and the circuit board are covered with a seal plate made of metal and mounted on an upper portion of the housing, which is a cover member for preventing electromagnetic wave intrusion, and further housed in an upper housing. The upper housing and the grommet are closed by bending and crimping the entire upper end of the housing.

A screw portion is formed at a lower portion of the housing, and the semiconductor pressure sensor is fixed by directly screwing the screw portion into a part of a vehicle engine to be measured, for example.

[0006]

The semiconductor pressure sensor having the above-mentioned conventional structure has been used for detecting the pressure of engine oil and the boost pressure of a turbo engine. These pressures are up to 1 MPa (megapascal) at the maximum, and when used for detecting a high pressure (for example, 3 MPa of the air pressure of an air brake), the chip size is increased and the sensor chip is increased. By increasing the contact area between the base 8 and the pedestal 7 and increasing the strength, it is possible to produce a device that can withstand high pressure. However, increasing the chip size causes an increase in cost.

Accordingly, an object of the present invention is to provide a semiconductor pressure sensor capable of detecting a high pressure.

[0008]

According to the present invention, a pressure introducing hole for introducing the pressure of a medium to be measured is provided in a pressure introducing member, a semiconductor is provided, and a base plate provided directly or indirectly with the semiconductor is provided. A semiconductor pressure sensor that receives the pressure of the medium to be measured introduced from the pressure introduction hole and detects the pressure of the medium to be measured by the semiconductor, so that the semiconductor faces the pressure introduction hole. The base plate is airtightly connected to the pressure introducing member.

A pressure introducing hole for introducing the pressure of the medium to be measured is provided in the pressure introducing member, a semiconductor is provided, and a base plate provided directly or indirectly with the semiconductor is provided. A semiconductor pressure sensor which receives the pressure of the medium to be measured and detects the pressure of the medium to be measured by the semiconductor, wherein a conductor electrically connected to the semiconductor is directly or indirectly connected to the base plate. A conductive member for transmitting an output from the semiconductor is provided on the base plate, and a conductor for electrically connecting the conductor and the conductor is provided, and a soft material covering at least the semiconductor, the conductor, and the conductor is provided. Comprising a member, the base plate,
Providing a storage portion for storing the soft member, via the soft member, the semiconductor, while receiving the pressure of the medium to be measured, so that the semiconductor faces the pressure introduction hole,
The base plate is airtightly connected to the pressure introducing member.

[0010] Further, the storage portion is formed in a separate form from the base plate.

Further, the base plate and the pressure introducing member are formed of metal, and the mold is formed of synthetic resin.

Further, at least a protector portion for protecting the semiconductor is provided integrally with the mold so as to be located between the pressure introducing hole and the semiconductor.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A semiconductor pressure sensor according to the present invention is provided with a pressure introducing hole 2 for introducing the pressure of a medium to be measured, a pressure introducing member 3, a semiconductor 40, and a semiconductor 40 directly or indirectly. A base plate 6 is provided and receives the pressure of the medium to be measured introduced from the pressure introduction hole 2 to receive the semiconductor 4.
0, a pressure sensor for detecting the pressure of the medium to be measured, wherein the base plate 6 is airtightly connected to the pressure introducing member 3 so that the semiconductor 40 faces the pressure introducing hole 2, and High pressure can be detected.

A pressure introducing hole 2 for introducing the pressure of the medium to be measured is provided in the pressure introducing member 3, a semiconductor 40 is provided, and a base plate 6 provided directly or indirectly with the semiconductor 40 is provided. A semiconductor pressure sensor which receives the pressure of the medium to be measured introduced from 2 and detects the pressure of the medium to be measured by the semiconductor 40, and directly or indirectly connects a conductor 41 electrically connected to the semiconductor 40. The base plate 6 is provided with lead pins 23 which are conductive members for transmitting an output from the semiconductor 40 to the base plate 6.
A lead 24 for electrically connecting the lead member 23 with the lead member 23; a soft member 21 for covering at least the semiconductor 40, the conductor 41, and the lead 24; and a housing part 38 for housing the soft member 21 in the base plate 6; The semiconductor 40 receives the pressure of the measured medium via the soft member 21,
By connecting the base plate 6 to the pressure introducing member 3 in an airtight manner so that the semiconductor 40 faces the pressure introducing hole 2, at least the semiconductor 40, the conductor 41, and the conductive wire 24 can be protected. Even when the soft member 21 is filled, the conductor 40, the conductor 41, the conductor 24, and the like can be reliably protected.

The storage portion 38 is formed by the cylindrical member 20 which is a separate body from the base plate 6, so that the lead pins 23 are attached before the cylindrical member 20 is attached to the base plate 6.
Since the work of connecting the conducting wire 24 to the wire can be performed, the workability is improved.

Since the base plate 6 and the pressure introducing member 3 are made of metal and the cylindrical member 20 is made of synthetic resin, when the pressure introducing member 3 and the base plate 6 are joined by electric welding, pressure is introduced. Since no current flows through the tubular member 20 located near the member 3, good welding can be performed.

In addition, at least a protector portion 36 for protecting the semiconductor 40 is provided integrally with the cylindrical member 20 so as to be located between the pressure introducing hole 2 and the semiconductor 40.
The semiconductor 40 can be protected.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the accompanying drawings. 1 to 4 show a first embodiment of the present invention. The semiconductor pressure sensor according to the present embodiment detects the pressure of a medium to be measured, which is a fluid such as water, oil, or gas, and has a screw portion 1 for attachment and a pressure introducing hole 2 provided at the lower portion. Pressure introducing member 3 and a synthetic resin housing 4 formed by insert molding the pressure introducing member 3.
, A metal base plate 6 disposed at the upper end of the pressure introducing hole 2, and a silicon chip provided with a semiconductor disposed on the base plate 6 via a glass pedestal 7. Chip 8, a circuit board 9 made of glass epoxy resin electrically connected to the sensor chip 8, a shield case 10 made of metal covering the circuit board 9 for preventing electromagnetic wave intrusion, An upper housing 14 made of synthetic resin having a lead pin 11 provided at an end for supplying an output signal to the outside, a connector terminal 12 connected to the lead pin 11, and a connector portion 13 facing a part of the connector terminal 12. It is composed of

The sensor chip 8 converts the pressure of the medium to be measured into an electric signal.
A semiconductor 40 such as a semiconductor strain gauge and a conductor 41 connected to the semiconductor 40 are formed on the surface of a silicon chip 39, and a thin diaphragm 42 is provided. A concave portion 22 is formed on the back surface of the sensor chip 8.

Since the sensor chip 8 and the pedestal 7 are joined in a vacuum, the space formed by the recess 22 is a vacuum. By making the recess 22 vacuum, the absolute pressure can be detected. On the other hand, a vent hole (not shown) is provided at the center of the pedestal 7 and the base plate 6, and a vent hole is formed at an arbitrary place of the upper housing 14 and connected to the outside, so that the relative pressure can be easily detected. It becomes possible.

Further, by receiving the pressure of the medium to be measured not on the side of the sensor chip 8 in contact with the pedestal 7 but on the side on which the semiconductor 40 is provided, it is possible to withstand high pressure with the same size as the conventional one. A simple semiconductor pressure sensor can be provided at low cost.

The pedestal 7 has a metallized layer formed on the surface facing the base plate 6 and is mounted by soldering on the base plate 6 described later.

The lower housing 5 includes a housing 4 made of, for example, polyphenylene sulfide (PPS), which is a heat-resistant and creep-resistant synthetic resin material, and a pressure introducing member 3.
And the sensor chip 8,
It functions to accommodate the pedestal 7 and the base plate 6.

The pressure introducing member 3 insert-molded in the lower housing 5 opens the inlet side of the pressure introducing hole 2 and serves to transmit the pressure of the medium to be measured to the sensor chip 8 via the pressure introducing hole 2. Eggplant At the lower part of the lower housing 5, a screw portion 1 is formed integrally with the lower housing 5, and the screw portion 1 is directly screwed and fixed to a measurement object such as a vehicle.

In this embodiment, by providing the concave and convex portion 14 at the contact portion of the pressure introducing member 3 with the container 4, the resin to become the container 4 enters the concave and convex portion 14 to improve the airtightness and strength. Become.

The pressure introducing member 3 is formed in a tubular shape by a metal material made of, for example, stainless steel.
One end of the pressure introducing hole 2 is opened to serve as an inlet for introducing pressure, and the other end is provided with a mounting portion 16 for disposing the base plate 6.
Is provided. On the side of the pressure introducing hole 2 where the mounting portion 16 is provided, a storage recess 17 for storing the sensor chip 8 and the like is formed.

The base plate 6 is made of a substantially circular member and made of a metal material such as Kovar having a thermal expansion coefficient close to the thermal expansion coefficient of the pedestal 7. Flange part 18 for disposing in part 15
And a raised step portion 19 connected to the pedestal 7.

The base plate 6 is provided with a lead pin 23 which is a conductive member penetrating the base plate 6,
The lead pin 23 is electrically connected to the conductor 41 of the sensor chip 8 and is connected to a conductive wire 24 such as gold for transmitting an output from the semiconductor 40.

The base plate 6 is hermetically joined onto the pressure introducing member 3 by welding the flange portion 16 and the mounting portion 15 of the pressure introducing member 3. By connecting the base plate 6 to the pressure introducing member 3 in an airtight manner, it is possible to accurately detect the high pressure of the medium to be measured without leaking.

A pedestal 7 is provided on the base plate 6, and serves as an intermediate member interposed between the pedestal 7 and the pressure introducing member 3 to absorb a difference in deformation due to a difference in thermal expansion coefficient between the two. Has made.

A cylindrical member 20, which is a mold made of synthetic resin, is provided around the step 19 of the base plate 6, and the step 19 is attached to the cylindrical member 20 by joining. I have.

The pedestal 7 and the sensor chip 8 are accommodated in an accommodating portion 38 surrounded by the base plate 6 and the cylindrical member 20, and this space is filled with a soft member 21 and sealed. The surface of the soft member 21 is concave.
The soft member 21 is a fluorosilicone gel, and the pressure of the medium to be measured is transmitted to the sensor chip 8 via the soft member 21. Thereby, the semiconductor 40, the conductor 41, and the conductor 24 can be protected.

Further, since the tubular member 20 is formed as a separate body, the work of connecting the lead wire 23 to the lead pin 23 can be performed before attaching the tubular member 20 to the base plate 6, so that workability is improved. .

By forming the storage portion 38, the semiconductor chip 8 and the lead pins 23 and the conductive wires 24 described later can be covered when the soft portion 21 is filled in the storage portion 38. In particular, even when the soft member 21 has a low viscosity, the conductor 4
0, the conductor 41, the conductor 24, etc., can be reliably covered and protected.

If the wall is formed up to a position higher than the height of the conductive wire 24,
The conductor 41, the conductor 24, and the like can be reliably covered and protected. Further, when the soft member 21 is filled in the storage portion 38, it can be easily visually determined whether or not the gas is contained in the soft member 21, and the gas has entered the soft member 21. Without going to the next manufacturing process.
A semiconductor pressure sensor with stable quality can be provided.

In the present embodiment, the cylindrical member 20 separate from the base plate 6 is used to form the storage portion 38. However, the base plate 6 can be used without using the cylindrical member 20. By forming a wall or recess integrally from
The storage portion 38 may be formed.

In this embodiment, since the pressure introducing member 3 and the base plate 6 are joined by electric welding, the cylindrical member 2
0 is formed of a synthetic resin. By forming with a synthetic resin, when performing electric welding, since electric current does not flow into the cylindrical member 20 located near the pressure introducing member 3, favorable welding can be performed.

The circuit board 9 covers the opening 4a of the housing 4 of the lower housing 5, as shown in FIG.
It is electrically connected by a plurality of lead pins 23 penetrating the base plate 6 and conductive wires 24 such as gold. The circuit board 9 includes an electronic component 43 constituting an amplifier circuit for amplifying an electric signal from the sensor chip 8 and a lead pin 11 for supplying the electric signal amplified by the amplifier circuit to the outside. .

A shield case 10 is provided so as to cover the circuit board 9. The shield case 10 has an opening on the lower side, abuts against a flange 25 provided on the entire periphery of the lower housing 5, and the base plate 6, the sensor chip 8, and the circuit board 9 are formed by the shield case 10 and the lower housing 5. And so on. The lead pins 11 provided on the circuit board 6 are connected to the shield case 10 via a feedthrough capacitor 26.
Penetrates.

The shield case 10, the circuit board 9,
The base plate 6 is electrically connected by the lead pins 27, and noise generated in the shield case 10 and the circuit board 9 is transmitted to the vehicle (not shown) through the base plate 6 and further through the pressure introducing portion 3. Grounded. In this embodiment,
The lead pins 27 are connected to the base plate 6 by brazing with silver or copper, but may be connected by welding or the like. As described above, the base plate 6 is brought into contact with the pressure introducing member 3 by means such as welding, and furthermore, the shield case 10 and the circuit board 9 are electrically connected to each other. Substrate 9
The noise generated by the noise is grounded to the vehicle, and a semiconductor pressure sensor which is hardly affected by the noise can be provided. A hole 35 is provided so that the lead pin 23 can be soldered to the circuit board 9.

The lead pin 11 is provided on the circuit board 9 and is a connector terminal 1 for supplying a signal detected by the sensor chip 8 and amplified by the amplifier circuit to the outside.
2 is soldered.

The connector terminal 12 is combined with the lower housing 5 to connect the sensor chip 8, the circuit board 9, and the amplifying circuit 7 to the connector 1 of the upper housing 11.
3 guides and supports the support member 28 via a support member 28 made of an elastic member, and is led out of the upper housing 11.
The support member 28 is partially inserted into a through hole (not shown) provided in the shield case 10 and is fitted and fixed in a recess 29 provided in the upper housing 14 in a press-fit state.

The upper housing 11 is formed of, for example, a resin material made of polybutylene terephthalate (PBT), and has a connector portion 13 provided with a concave portion 30 at the upper portion. The connector terminal 12 is pulled out.

When the upper housing 11 is combined with the lower housing 5, a step 31 provided on the entire inner surface of the upper housing 11 and a flange 25 of the lower housing 5 are provided.
Then, the flange 32 provided around the entire opening of the shield case 10 is clamped. In addition, a groove 33 is provided on the entire side surface of the lower housing 5, an O-ring 34 is provided in the groove 33, and the upper housing 14 is provided. Further, the upper housing 11 is fixed to the lower housing 5 by heat caulking so as to bend the entire lower end portion inward.

FIGS. 5 and 6 show a second embodiment of the present invention, in which a protector section 36 for protecting the sensor chip 8 is provided on the cylindrical member 20.
6 has three legs 37.

The protector 36 is located between the pressure introducing hole 2 and the sensor chip 8 having the semiconductor 40. The protector 36 penetrates the soft member 21 by a foreign substance entering through the pressure introducing hole 2, and And the conductor 24 and the like are protected from being damaged.

In this embodiment, when the protector 36 is viewed from the pressure introducing hole 2 side, there is a portion where the sensor chip 8 is covered and the conductive wire 24 is partially exposed. The exposed portion is the communication portion 44. For example, as shown in FIG. 7, even when the protector portion 36 comes into contact with the pressure introducing hole 2 when the tubular member 20 falls off, the pressure is The pressure transmission hole 2 is configured to prevent the pressure introduction hole 2 from being blocked by the protector portion 36, thereby preventing the pressure from being transmitted.

For example, when the protector portion 36 is viewed from the pressure introducing hole 2 side, the protector portion 36 may be formed so as to cover not only the sensor chip 8 but also the entire conductor 24 and the like. In this case, a cut-out portion may be formed as the communication portion 44 for transmitting pressure to a surface of the protector portion 36 facing the pressure introduction hole 2. With this configuration, the sensor chip 8 and the conductive wire 24 can be more reliably protected, and when the tubular member 20 falls off, the pressure introducing hole 2 is closed by the protector portion 36, and the pressure is reduced. It can be prevented from being lost.

When the diameter of the inlet of the pressure introducing hole 2 is different from the diameter of the sensor chip 8 side, it is sufficient that the diameter is larger than the diameter of the sensor chip 8 instead of the diameter of the inlet side. .

The protector 36 is connected to the cylindrical member 2.
By forming the protector portion 36 separately from the tubular member 20, the tubular member 2 is formed integrally with the tubular member 20.
There is no danger that the protector portion 36 formed integrally with the pressure sensor 0 will fall out of the pressure introducing hole 2.

In each of the above embodiments, the sensor chip 8
Is a device utilizing a piezoresistive effect of silicon. A diffused resistor is formed on a silicon chip 40 by a semiconductor planar technology, and the back surface thereof is etched to form a thin diaphragm 42 which is sensitive to pressure.
0, the conductor 41 is provided indirectly on the base plate 6 via the silicon chip 39 and the pedestal 7, but is not limited to the above embodiment, and any semiconductor or conductor may be used. For example, a semiconductor and a conductor may be directly provided on the base plate 6 via an insulating layer (not shown) by vapor deposition, and a thin diaphragm provided on the base plate 6 may be used. In this case, the pedestal 7 and the silicon chip are not required as compared with the embodiment.

In each of the above embodiments, a semiconductor pressure sensor for detecting a high pressure is used. However, there is no problem if the structure of the present invention is applied to a semiconductor pressure sensor for detecting a low pressure.

[0053]

As described above, according to the present invention, it is possible to provide a semiconductor pressure sensor which can achieve the intended purpose.

[Brief description of the drawings]

FIG. 1 is a top view showing a first embodiment of the present invention.

FIG. 2 is a side view of the embodiment.

FIG. 3 is a sectional view taken along line AA in FIG.

FIG. 4 is an enlarged sectional view of a main part of the embodiment.

FIG. 5 is a sectional view showing a main part of a second embodiment of the present invention.

FIG. 6 is a front view of the same example as viewed from the pressure introduction hole side.

FIG. 7 is a sectional view of a main part of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Screw part 2 Pressure introduction hole 3 Pressure introduction member 4 Housing 4a Opening 5 Lower housing 6 Base plate (metal plate) 7 Pedestal (glass) 8 Sensor chip 9 Circuit board 10 Shield case 11 Lead pin 12 Connector terminal 13 Connector part 14 Upper housing 15 Concavo-convex part 16 Mounting part 17 Storage concave part 18 Flange part 19 Step part 20 Cylindrical member (mold) 21 Soft member 22 Concave part 23 Lead pin 24 Conductive wire 25 Flange part 26 Through capacitor 27 Lead pin 28 Support member 29 Concave part 30 Recess REFERENCE SIGNS 31 step portion 32 flange 33 groove portion 34 O-ring 35 hole portion 36 protector 37 leg portion 38 housing portion 39 silicon chip 40 semiconductor 41 conductor 42 diaphragm 43 electronic component 44 communication portion

Claims (5)

[Claims] 1. A pressure introducing hole for introducing a pressure of a medium to be measured is provided in a pressure introducing member, a semiconductor is provided, and a base plate provided directly or indirectly with the semiconductor is provided. Receiving the pressure of the medium to be measured,
A semiconductor pressure sensor for detecting a pressure of the medium to be measured by the semiconductor, wherein the base plate is airtightly connected to the pressure introducing member so that the semiconductor faces the pressure introducing hole. Pressure sensor. 2. A pressure introducing hole for introducing a pressure of a medium to be measured is provided in a pressure introducing member, a semiconductor is provided, and a base plate provided directly or indirectly with the semiconductor is provided. Receiving the pressure of the medium to be measured,
A semiconductor pressure sensor for detecting the pressure of the medium to be measured by the semiconductor, wherein a conductor electrically connected to the semiconductor is provided directly or indirectly on the base plate,
A conductive member for transmitting output from the semiconductor is provided on the base plate, and a conductor for electrically connecting the conductor and the conductor is provided, and a soft member covering at least the semiconductor, the conductor, and the conductor is provided. In the base plate, a storage portion for storing the soft member is provided, and through the soft member, the semiconductor receives the pressure of the medium to be measured, and the semiconductor faces the pressure introduction hole. A semiconductor pressure sensor, wherein the base plate is airtightly connected to the pressure introducing member. 3. The semiconductor pressure sensor according to claim 2, wherein said housing portion is formed by a separate body from said base plate. 4. The semiconductor pressure sensor according to claim 3, wherein said base plate and said pressure introducing member are formed of metal, and said mold is formed of synthetic resin. 5. The semiconductor pressure according to claim 3, wherein a protector portion for protecting at least the semiconductor is provided integrally with the mold so as to be located between the pressure introducing hole and the semiconductor. Sensor.