JPH05302864A - Pressure sensor - Google Patents

Abstract

PURPOSE:To obtain a pressure sensor, whose manufacture is easy, by improving wire connecting workability. CONSTITUTION:The opening part of a body 1 is closed with a diaphragm 2. A pin 3 is made to penetrate through the body 1. A sensor chip 4 and a spacer 5 comprising an insulating material are provided in a space between the body 1 and the diaphragm 2. The spacer 5 has a hole 6. A solder pad part 7 is formed in the opening part of the hole 6. The solder pad part 7 is formed of conductive paste or gold plating. The pin 3 is inserted into the hole 6 of the spacer 5 and soldered to the solder pad part 7, and the sensor chip 4 and the solder pad part 7 are connected. At this time, the solder pad part 7 can be formed in the flat and relatively broad-area state on the spacer 5. Therefore, the wire connecting work between the solder pad part 7 and the sensor chip 4 can be readily performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure sensor, and more particularly to a pressure sensor which detects a pressure acting on a diaphragm as an electric signal corresponding to the magnitude of the pressure.

[0002]

2. Description of the Related Art Conventionally, there is a pressure sensor of this type as shown in FIG. That is, FIG.
The pressure sensor shown in FIG. 2 has a sensor chip 24 in a space formed by a body 21 having an opening and a diaphragm 22 provided so as to close the opening of the body 21.
And a pin 23 which is connected to the sensor chip 24 and which extends through the inside of the body 21 and extends outward. When pressure is applied to the diaphragm 22, the sensor chip 24 The pressure is detected, and this detection signal is output to the outside via the pin 23.

In FIG. 4, a body 21 is made of metal and has a substantially cylindrical shape, and has a partition wall portion 29 that divides the inside into two parts. Due to the presence of the partition wall portion 29, a void space that opens to one side and a void space that opens to the other are formed inside the body 21.

A diaphragm 22 is provided in one opening of the body 21 so as to close the opening. This diaphragm 22 is a so-called metal diaphragm 22.
And has a disc shape and flexibility,
When pressure is applied, the diaphragm 22 is displaced in the axial direction according to the magnitude of the pressure.

When the diaphragm 22 is arranged on the body 21, one inner space of the body 21 is sealed by the diaphragm 22, and therefore the pressure acting on the diaphragm 22 is changed by the displacement of the diaphragm 22. 21 will be transmitted to one of the voids.

[0006] The bottom of one of the voids of the body 21 (partition wall 2
The sensor chip 24 is arranged in the central portion of 9). Although not shown, the sensor chip 24 has a pressure sensor element such as a strain gauge attached to the center portion of the surface thereof. After forming the strain-flexing portion, a strain gauge is diffused on the surface of the strain-flexing portion, and the strain gauge is connected to the bridge by a wire formed by vapor deposition of aluminum.

The pressure sensor element attached to the sensor chip 24 is designed to be displaced when pressure is applied, and the internal electrical resistance value changes according to the amount of displacement at this time. As a result, the pressure is detected as an electrical signal.

Silicon oil, which is a pressure transmitting medium, is enclosed in one of the voids of the body 21 which is sealed by the diaphragm 22, and the pressure acting on the diaphragm 22 is transmitted through this silicone oil. It is transmitted to the sensor chip 24.

A plurality of pins 2 are provided on the partition wall 29 of the body 21.
3 are evenly penetrated. At this time, one end of the pin 23 is projected to one space side of the body 21, and the other end is projected to the other space side of the body 21.

At this time, a so-called hermetic seal is made between the pin 23 and the partition wall portion 29 of the body 21 by an insulating material 28 made of glass or the like, so that the pin 23 and the body 21 are electrically connected. It electrically insulates and prevents silicon oil filling one space of the body 21 from leaking to the outside.

One end of the pin 23 projecting to the one space side of the body 21 is connected to the sensor chip 24 by means such as wire bonding, and is connected to a pressure sensor element (not shown) on the sensor chip 24. The pin 23 is electrically connected. And pin 23
The other end is connected to a circuit member on which an amplifier circuit or the like is formed (not shown) at the end thereof, whereby the sensor chip 24 and the circuit member (not shown) are electrically connected via the pin 23. I am trying.

With this structure, when pressure acts on the diaphragm 22, the pressure sensor displaces the diaphragm 22 so that the pressure is transmitted to the inside of the body 21. Then, this pressure is further transmitted to the sensor chip 24 via the pressure transmission medium filled in the body 21, and the sensor chip 24 is responsive to the magnitude of the pressure at this time.
An electric signal is generated from the upper pressure sensor element, and this detects that the pressure acts.

The electric signal generated in the sensor chip 24 is guided to a circuit member (not shown) on the other side through the pin 23, is subjected to processing such as amplification on the circuit member, and is then output to the outside. As a result, as a result, the pressure acting on the diaphragm 22 can be detected.

However, in such a conventional pressure sensor, the workability of connecting the sensor chip 24 and the pin 23 is low, and it is difficult to manufacture the pressure sensor.

In general, wire bonding is usually used as a means for connecting the sensor chip 24 and the pin 23. At this time, in order to suppress the electric resistance of the connected portion of the wire 23 to be low, the wire bonding of the pin 23 is suppressed. It is necessary to apply gold plating on the surface.

However, in order to adopt the wire bonding means, it is important that the surface of the gold plating applied to the pin 23 which is the object of connection is in a uniform state. If it is not uniform, the connection cannot be made. Therefore, in order to make the surface of the gold plating uniform, it is necessary to make the surface of the pin 23 uniform, and the precision of the surface processing of the pin 23 becomes strict, and setting of these various conditions becomes very troublesome. It was

When the pin 23, which is a target member for one-a-bonding, is plated with gold, the protruding end of the pin 23 is plated when the pin 23 is fixed to the body 21 by a hermetic seal. Therefore, the part of the body 21 where one opening is formed becomes an obstacle to the plating operation. Therefore, the cost of the plating process becomes high, which causes an increase in manufacturing cost.

Similarly, when the wire bonding means is used to connect the sensor chip 24 and the pin 23, the connection is made when the pin 23 is fixed to the body 21 by the hermetic seal. Therefore, the body 21 becomes an obstacle. Therefore, the work of the connection is significantly hindered and the workability is deteriorated.

The present invention solves the above problems, and an object of the present invention is to provide a pressure sensor capable of improving workability of connection and facilitating manufacture.

[0020]

In order to solve the above problems, the present invention provides a body having an opening, a diaphragm provided so as to close the opening of the body, the diaphragm and the body. And a sensor chip provided in the cavity formed by and one end projecting into the cavity, the other end penetrating the body and extending outward, the body and the diaphragm. And a spacer made of an insulating material having a hole through which one end of the pin can be inserted and having a solder pad formed in one opening of the hole. The solder pad portion of the spacer is connected to the sensor chip, and the solder pad portion is connected to the pin.

[0021]

The present invention, by adopting the above means,
When pressure acts on the diaphragm, an electric signal corresponding to the magnitude of the pressure is generated from the sensor chip. Then, the electric signal generated from this sensor chip is guided to the pin via the solder pad portion on the spacer,
Further, the pin is guided to the outside so that the pressure can be detected.

Further, according to the present invention, it is possible to improve the workability at the time of connecting the sensor chip and the solder pad portion which is the member to be connected.

That is, since the solder pad portion, which is the member to be connected to the sensor chip, is formed on the spacer, which is a separate body from the body, the solder pad has a large surface area on the spacer. It is possible to form a portion, which facilitates connection work between the sensor chip and the solder pad portion.

Further, in this case, since the spacer is separate from the body, it is possible to form the solder pad portion outside the body. Therefore, the condition (uniformity of the surface) required as a member to be connected. Can be set easily.

[0025]

Embodiments of the present invention shown in the drawings will be described below.

FIG. 1 is a diagram showing an embodiment of a pressure sensor according to the present invention, FIG. 2 is a diagram showing a cross section taken along the line AA in FIG. 1, and FIG. 3 is a diagram illustrating an essential part of the present invention. FIG.

That is, the pressure sensor shown in FIGS. 1 to 3 has a body 1 having an opening, and a diaphragm 2 provided so as to close the opening of the body 1.
A sensor chip 4 provided in a void formed by the body 1 and the diaphragm 2, one end of which protrudes toward the void, and the other end of the sensor chip 4 penetrates the inside of the body 1 to the outside. The pin 3 is extended, and a hole 6 through which one end of the pin 3 can be inserted is formed in a cavity formed by the body 1 and the diaphragm 2, and one of the holes 6 is inserted. The solder pad portion 7 is formed in the opening of the spacer 5, and the disk-shaped spacer 5 on which the sensor chip 4 can be arranged is arranged. First, the solder pad portion 7 of the spacer 5 and the sensor are arranged. The chip 4 is connected, and the solder pad portion 7 and the pin 3 are further connected.

When pressure acts on the diaphragm 2, the sensor chip 4 detects the pressure, and the detection signal is output to the outside via the pin 3.

In FIG. 1, the body 1 is made of metal and has a substantially cylindrical shape, and has a partition wall portion 9 that divides the inside into two parts. Due to the presence of the partition wall portion 9, a void space that opens to one side and a void space that opens to the other are formed inside the body 1.

A diaphragm 2 is provided in one opening of the body 1 so as to close the opening. This diaphragm 2 is a so-called metal diaphragm 2,
It has a disc shape and flexibility, and when a pressure acts on it, the diaphragm 2 is displaced in the axial direction according to the magnitude of the pressure.

When this diaphragm 2 is arranged on the body 1, one inner space of the body 1 is sealed by the diaphragm 2, and therefore the pressure acting on the diaphragm 2 is changed by the displacement of the diaphragm 2. 1 will be transmitted to one of the voids.

As shown in FIG. 2, a plurality of pins 3 are equally penetrated through the partition wall 9 of the body 1. At this time, one end of the pin 3 is made to project to one space side of the body 1, and the other end is made to project to the other space side of the body 1.

Here, the other end of the pin 23 is connected to a circuit member having an amplifier circuit and the like, not shown, at the end thereof so as to be electrically conducted.

A disc-shaped spacer 5 is provided on the bottom (partition wall 9) of the body 1 on the side of one space. The spacer 5 is made of an insulating material such as ceramic,
The same number of holes 6 as the size of the pins 3 are formed so that the pins 3 can be inserted, and the holes 6 are arranged so as to correspond to one protruding end of the pins 3, respectively.

An annular solder pad portion 7 is formed on one end surface of the spacer 5 so as to surround the opening corresponding to each hole 6. In this case, the solder pad portion 7 is formed of, for example, gold plating or conductive paste.

A recess is formed in the center of the end surface of the spacer 5 on the diaphragm 2 side, and the sensor chip 4 is disposed in this recess. This sensor chip 4
Although not shown, a pressure sensor element such as a strain gauge is attached to the center of the surface of the surface.
A line formed by forming an ultra-thin strain element in the center of a silicon single crystal by etching, etc., then diffusing a strain gauge on the surface of the strain element, and vapor-depositing this strain gauge on aluminum. And is configured by connecting to the bridge.

The pressure sensor element attached to the sensor chip 4 is designed to be displaced when pressure is applied.
The internal electrical resistance value changes according to the amount of displacement at this time, whereby the pressure is detected as an electrical signal.

As shown in FIG. 3, the sensor chip 4 is connected to the solder pad portion 7 of the spacer 5 by means such as wire bonding, and the pressure sensor element (not shown) and the solder pad portion on the sensor chip 4 are connected. 7 and 7 are electrically connected.

The spacer 5 in which the sensor chip 4 is connected and incorporated in this way is placed in one space of the body 1 with its end face on the side where the solder pad portion 7 is formed facing the diaphragm 2 side. At this time, the protruding end of the pin 3 is inserted into the hole 6 of the spacer 5 and protrudes from the end face of the spacer 5.

The solder pad portion 7 of the spacer 5 and
By soldering between the ends of the pins 3 protruding from the spacer 5, the solder pads 7 and the pins 3 are electrically connected.

Here, since the solder pad portion 7 is formed of a conductor such as gold plating or a conductive paste, the pressure sensor element on the sensor chip 4 and the pin 3 are electrically connected via the solder pad portion 7. It is designed to conduct electricity.

Silicon oil, which is a pressure transmitting medium, is enclosed in one of the voids of the body 1 which is sealed by the diaphragm 2, and the pressure acting on the diaphragm 2 is transmitted through this silicone oil. It will be transmitted to the sensor chip 4.

In this case, a so-called hermetic seal is made between the pin 3 and the partition wall portion 9 of the body 1 by an insulating material 8 made of glass or the like, whereby an electrical connection is made between the pin 3 and the body 1. In addition to being insulated, the silicone oil filling one void of the body 1 is prevented from leaking to the outside.

In FIG. 1, reference numeral 11 is a threaded portion for screwing onto the object to be measured, and the threaded portion 11 allows the pressure sensor to be fixed to the object to be measured. Reference numeral 10 denotes an O-ring, which seals the space between the pressure sensor and the body to be measured when the pressure sensor is attached to the body to be measured.

Further, 12 is an injection hole, and by injecting the pressure transmission medium through this injection hole 12, the space formed between the body 1 and the diaphragm 2 is filled with the pressure transmission medium. After that, by press-fitting the ball into the injection hole 12, the pressure transmission medium is enclosed in the space formed between the body 1 and the diaphragm 2.

Next, the operation of the above will be described.

When this pressure sensor is attached to the body to be measured and then pressure is applied to the diaphragm 2, the diaphragm 2 is displaced, and the pressure is transmitted to the inside of the body 1. Then, this pressure is further transmitted to the sensor chip 4 via the pressure transmission medium filled in the body 1, and an electric signal is generated from the pressure sensor element on the sensor chip 4 according to the magnitude of the pressure at this time. However, by this, it is detected that the pressure acts.

The electric signal generated in the sensor chip 4 is guided to the pin 3 via the solder pad portion 7 and then to the circuit member (not shown) via the pin 3 to form this circuit. Processing such as amplification is performed on the member, and then it is output to the outside, and as a result,
The pressure acting on the diaphragm 2 is detected as an electric signal.

In this pressure sensor, the workability of connecting the sensor chip 4 and the solder pad portion 7 to be connected can be improved.

That is, since the sensor chip 4 is incorporated in the spacer 5 existing as a separate body, the work of connecting the sensor chip 4 and the solder pad portion 7 formed on the spacer 5 can be performed outside the body 1. It is like this.

That is, the sensor chip 4 and the solder pad portion 7
The connection work between the sensor chip 4 and the solder pad portion 7 is performed by first assembling the sensor chip 4 into a recess formed in the central portion of the spacer 5, and then connecting the sensor chip 4 and the solder pad portion 7 by means of wire bonding or the like. Therefore, this series of operations can be independently performed on the board of the spacer 5, whereby the wiring work can be performed outside the main body 1.

Therefore, after the sensor chip 4 and the solder pad portion 7 are connected on the spacer 5 as a separate process, the spacer 5 can be integrated with the sensor chip 4 at a predetermined position of the body 1. Unlike the conventional case, the body 1 does not get in the way during the wiring work.

Along with this, the solder pad portion 7 which is the object member of wire bonding is the conventional one (pin 2).
Since the surface area can be increased as compared with 3), the range of the target point of connection can be set larger by this, and as a result, the workability of connection can be improved. Is becoming

Further, in this case, since the solder pad portion 7 which is the object member of wire bonding is formed by applying the conductive paste or gold plating on the spacer 5 which is present separately from the body 1, the solder pad portion is formed. 7 will be easily formed.

That is, since the target member for wire bonding is the pin 23 fixed to the body 21 in the related art, when the pin 23 is plated with gold, the body 21 is fixed.
Was hindering its workability,
In this pressure sensor, since the target member for wire bonding is the solder pad portion 7 on the spacer 5, the solder pad portion 7 can be formed outside the body 1.

Therefore, the solder pad portion 7 which is the target member for wire bonding may be formed by applying conductive paste, gold plating, etc. to the single spacer 5 outside the body 1. It doesn't get in the way.

At this time, when the solder pad portion 7 is formed, the end surface of the spacer 5 is coated with a conductive paste or gold plating, but the spacer 5 made of ceramic, resin or the like is surface-processed. Is relatively easy, the spacer 5 can easily form a flat end surface.

Therefore, the solder pad portion 7 formed on the flat end face of the spacer 5 can be easily obtained in a uniform state, and as a result, wire bonding means is adopted. The solder pad portion 7 and the sensor chip 4 can be connected together.

As a result of the above, the cost of the gold plating treatment of the solder pad portion 7 can be suppressed to 1/5 or less as compared with the conventional one.

[0060]

As described above, according to the present invention, the solder pad portion is formed on the spacer provided in the space of the body on the side where the sensor chip is arranged, and the solder pad portion of the spacer and the sensor chip are connected to each other. Since the wires are connected, it is possible to easily set various conditions for wire connection.
Therefore, the connection work can be performed more easily and surely than in the past.

Therefore, the workability of the wiring can be improved, and accordingly, the pressure sensor can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a pressure sensor according to the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a diagram showing a main part of the present invention.

FIG. 4 is a diagram showing a conventional example.

[Explanation of symbols]

 1, 21 ...... Body 2, 22 ...... Diaphragm 3, 23 ...... Pin 4, 24 ...... Sensor chip 5 ...... Spacer 6 ...... Hole 7 ...... Solder pad part 8, 28 ...... Insulation material 9, 29 ... … Partition wall 10 …… O-ring 11 …… Screw part 12 …… Injection hole

Claims (1)

[Claims] 1. A body (1) having an opening, a diaphragm (2) provided so as to close the opening of the body (1), and the diaphragm (2) and the body (1). And a sensor chip (4) provided in the empty space, and one end of which protrudes into the empty space,
The other end is provided in a void formed by the pin (3) penetrating the body (1) and extending outward, and the body (1) and the diaphragm (2). (3) A spacer (5) made of an insulating material having a hole (6) through which one end of the hole (6) can be inserted, and a solder pad (7) formed in one opening of the hole (6); The solder pad portion (7) of the spacer (5) and the sensor chip (4) are connected, and the solder pad portion (7) and the pin (3) are connected. Pressure sensor.