JP3182753B2 - Pressure detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure detector, and more particularly to a pressure detector for detecting a pressure of a medium to be measured by a semiconductor chip.

[0002]

2. Description of the Related Art A pressure detector for detecting the pressure of a medium to be measured is disclosed in Japanese Patent Application Laid-Open No. 3-273332. This pressure detector is a semiconductor chip in which a diaphragm having a semiconductor strain gauge formed on a glass pedestal is anodically bonded to the bottom surface of a metal lower case having a pressure introduction port for introducing the pressure of the medium to be measured. A base plate provided with the semiconductor chip is disposed in a state where the pressure is applied to the semiconductor chip, and a circuit board electrically connected to the semiconductor chip by wire bonding is formed on an inner wall of the lower case. And is fixed to the stepped portion via a silicon-based adhesive.

[0003] Further, a gel member such as silicon gel is provided in the lower case so as to cover the circuit board,
The circuit board and the semiconductor chip are not exposed to the atmosphere.

[0004]

In the pressure detector having such a structure, the circuit board is fixed to the step portion of the lower case by the silicon-based adhesive. Below, for example, if the above-described configuration is adopted with a pressure detector that directly detects the oil pressure of the engine and is directly attached to the engine, the circuit board, which is merely fixed by an adhesive of a soft material, vibrates, and the semiconductor chip and the circuit There is a possibility that a connection wire for electrically connecting the substrate may be broken.

Accordingly, the present invention focuses on the above-mentioned problems, and a pressure detection method capable of improving the reliability of the electrical connection between a circuit board and a semiconductor chip even under a condition in which a large vibration or impact is applied. To provide a vessel.

[0006]

In order to solve the above-mentioned problems, the present invention provides a case body having a pressure introduction port for introducing the pressure of a medium to be measured , and a base mounted on the pressure introduction port.
A semiconductor chip disposed under the pressure through a plate, and a storage hole for storing the semiconductor chip.
With the semiconductor chip and electrically connected to the semiconductor chip.
A circuit board disposed in the case body so as to be located on a board, and fixed to a bottom surface of the case body,
And a board holder having a pair of holding portions for holding the circuit board.

Further, the substrate holder is provided with a restricting portion for determining an arrangement direction with respect to the case body.

[0008]

Further, the substrate holder is provided with a positioning portion for determining an arrangement direction of the circuit board.

[0010] Further, a fixing portion corresponding to the holding portion is formed near the periphery of the circuit board.

Further, the semiconductor sensor of the circuit board and
Only around the wire bonding point and the storage hole
It is provided with a covering gel-like member.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the present invention, a base plate 4 provided with a semiconductor chip 5 for detecting the pressure of a medium to be measured is placed on a lower case (case body) while the semiconductor chip 5 receives pressure.
3 and a circuit board 6 electrically connected to the semiconductor chip 5 is connected to the first step portion 1a formed on the inner wall of the lower case 3 so as to be located on the base plate 4. A pressure detector that is disposed and fixed to the bottom surface of the lower case 3 and holds the circuit board 6 by a board holder 7 having a pair of holding portions 7b. Therefore, large vibration,
Even in the case where the pressure detector is used under such a condition that an impact is applied, the reliability of the electrical connection between the circuit board 6 and the semiconductor chip 5 can be improved.

Further, the board holder 7 is provided with a regulating portion 7d for determining the disposing direction with respect to the lower case 3, and a positioning portion 7b3 for determining the disposing direction of the circuit board 6,
The assembling workability in the manufacturing process of the pressure detector can be improved.

A hole (fixing portion) 6b corresponding to the holding portion 7b of the substrate holder 7 is formed in the circuit board 6 of a soft member made of resin containing glass fiber, paper phenol, or the like.
, The bending of the circuit board 6 that occurs when the circuit board 6 is assembled to the lower case 3 can be prevented.

Further, since the semiconductor chip 5 is housed in the housing hole 6a formed in the circuit board 6 and the gel resin 17 covers only the periphery of the wire bonding portion of the circuit board 6 and the housing hole 6a, The reliability of the electrical connection between the circuit board 6 and the semiconductor chip 5 can be further improved.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The pressure detector according to the present embodiment detects the pressure of a medium to be measured such as water or oil. FIG. 1 is a sectional view of a main part showing an entire configuration of the pressure detector according to the present invention, and FIG. Is a plan view showing a state viewed from above, and FIG. 3 is a side view of the substrate holder.

The pressure detector in the present embodiment has a cylindrical portion 1
A lower case (case body) 3 composed of a pressure introduction port 2, a base plate 4 disposed at the upper end of the pressure introduction port 2, and a pressure plate disposed on the base plate 4. The semiconductor chip 5, a circuit board 6 electrically connected to the semiconductor chip 5, a board holder 7 for arranging and fixing the circuit board 6 to the lower case 3, and absorbing noise from a power supply line or the like supplied from the outside. Capacitor 9 for arranging feedthrough capacitor 8 for connection, and connector 1 for electrically connecting feedthrough capacitor 8 and wiring cord 10
1 and an upper case 12 disposed at the upper end of the cylindrical portion 1.

The cylindrical portion 1 is made of a metal material such as stainless steel and has an opening for disposing the pressure introducing port 2. The cylindrical portion 1 has a first step portion 1a for disposing the circuit board 6, a second step portion 1b for disposing the capacitor holder 9, and a disposition for disposing the upper case 12. The third step portion 1c is formed sequentially from below the inner wall upward, and a joining portion 1d for joining with the pressure introduction port 2 is formed at a lower end portion of the cylindrical portion 1.

The pressure introduction port 2 is made of a metal material such as stainless steel, and has a mounting portion 2a having a convex shape for disposing the base plate 4 and a bottom surface of the pressure passage entrance port 2 from the mounting portion 2a. Pressure introduction hole 2 for introducing said pressure through
b are formed. In addition, below the mounting portion 2a,
An arrangement portion 2c is formed to be smaller in diameter than the outer diameter of the pressure introduction port 14 and to arrange the joint portion 1d of the cylindrical portion 1.

The joining portion 1d of the cylindrical portion 1 is connected to the pressure introducing port 2
The lower case 3 having the pressure introduction port 2 for introducing the pressure can be obtained by arranging the two members 1d and 2c by TIG welding.

The base plate 4 has a substantially circular shape and is made of a metal material such as Kovar having a thermal expansion coefficient close to that of the semiconductor chip 5. The base plate 4 is fitted with a flange portion 4 a for disposing on the mounting portion 2 a of the pressure introduction port 2 and a pressure introduction hole 2 b of the pressure introduction port 2. A protruding portion 4 b for determining the disposition position and a pressure introducing hole 4 c penetrating from the protruding portion 4 b to the upper surface of the base plate 4 are formed.

The base plate 4 has a flange portion 4 of the base plate 4.
a and the mounting portion 2a of the pressure introduction port 2 are welded to each other to be disposed on the pressure introduction port 2 in an airtight manner.

The semiconductor chip 5 is formed by airtightly bonding a thin diaphragm having a semiconductor strain gauge formed on a glass pedestal by an anodic bonding method, and transmits the pressure to the glass pedestal to the diaphragm. Pressure introducing hole 5a is formed. Further, in the semiconductor chip 5, a metallized layer is formed on the surface of the glass pedestal facing the base plate 4, and the pressure introduction hole 4c of the base plate 4 and the pressure introduction hole 5a of the semiconductor chip 5 are opposed to each other. It is airtightly bonded on the base plate 4 via solder so as to be transmitted to the diaphragm.

The circuit board 6 is electrically connected to the semiconductor chip 5 by wire bonding.
It is made of a soft material such as resin containing glass fiber or paper phenol, and has a substantially circular shape. At substantially the center of the circuit board 6, a storage hole 6a penetrating the front and back surfaces for storing the semiconductor chip 5 is formed.
A hole (fixing portion) 6b corresponding to a pair of holding portions of the substrate holder 7, which will be described in detail later, is formed. A land portion (not shown) for connecting and fixing the protruding portion of the holding portion with solder around the hole portion 6b on the surface of the circuit board 6.
Are formed. On the back side of the circuit board 6 and inside the hole 6b, an electronic component 13 composed of an amplifier circuit for amplifying the output of the semiconductor chip 5 is mounted, and on the front side of the circuit board 6 A terminal 14 electrically connected to the feedthrough capacitor 8 is mounted. The circuit board 6 is disposed on the first step portion 1 a of the lower case 3 and is located on the base plate 4 disposed on the mounting portion 2 a of the pressure introduction port 2.

The substrate holder 7 is a feature of the present invention, and will be described in detail with reference to FIGS. The substrate holder 7 is made of a metal material such as SPC. The substrate holder 7 has a substantially square base portion 7a in which each corner is cut out in an arc shape, and a base 2a facing the base portion 7a.
A pair of holding portions 7b formed by bending the base portion 7a in a substantially vertical direction from the sides, and a substantially larger center of the base portion 7a than the outer diameter of the base plate 4 and the substrate holder 7 being attached to the bottom surface of the lower case 3. Hole 7c for disposing the base plate 4 disposed on the pressure introduction port 2 above the substrate holder 7, and one of the base portions 7a.
A restricting portion 7 d that protrudes outward from the side and that determines the direction in which the substrate holder 7 is disposed with respect to the lower case 3 is formed. The holding portion 7b is provided with the hole 6b of the circuit board 6.
And a mounting portion 7b2 for arranging the circuit board 6 are formed. Further, in the pair of holding parts 7a, one guide part 7b1 is mounted on the mounting part 7b2.
And the other guide portion 7b1 is formed so as to be located at a multi-end with respect to the mounting portion 7b2. That is, the other guide portion 7b1 is formed so as to be close to the multiple ends, thereby forming a positioning portion 7b3 for determining the direction in which the circuit board 6 is disposed with respect to the board holder 7.

The above-mentioned substrate holder 7 is, for example, caulked at a step (not shown) formed on the bottom surface of the lower case (cylindrical portion 1) 3 at a position corresponding to the four arc portions of the base portion 7a. Thereby, it is arranged and fixed on the bottom surface of the lower case 3.

The capacitor holder 9 is made of a metal material such as SPC, and has a feedthrough capacitor 8 with a lead pin 8a.
Is provided on the second step portion 1b of the cylindrical portion 1 with a mounting piece 9a for disposing in a horizontal state.

The connector 11 is formed by insert-molding a lead pin 11b on a base 11a made of an elastic material such as rubber. The connector 11 is formed by fitting the mounting piece 9a of the capacitor holder 9 into a slit 11c formed in the base 11a and disposing an upper portion of the base 11a in a hole of an upper case 12 described in detail later.
And the capacitor holder 9.

The wiring cord 10 supplies the power supply system of the semiconductor chip 5 from the outside or transmits the output of the semiconductor chip 5 to the outside. The wiring cord 10 is connected to the connector 1
It is electrically connected to the semiconductor chip 5 via the one lead pin 11b, the feedthrough capacitor (lead pin 8a) 8, the terminal 14 mounted on the circuit board 6, and the circuit board 6.

The upper case 12 is made of a resin material such as polybutylene terephthalate (PBT). A recess 12a is formed in the upper part of the upper case 12, and a hole 12b for disposing the base 11a of the connector 11 is formed in the bottom of the recess 12a. A flange portion 12 corresponding to the third step portion 1c of the cylindrical portion 1 is provided at a lower portion of the upper case 12.
c, extending downward from the flange portion 12c,
And a holding portion 12d on which the O-ring 15 is provided.

The wiring cord 10 is disposed on the wall of the concave portion 12a of the upper case 12 via a grommet 16, and the concave portion 1a is provided.
The wiring cord 10 is arranged and fixed by filling the interior of the 2a with an epoxy resin or the like. The upper case 12 is fixed to the upper portion of the cylindrical portion 1 by arranging the flange portion 12c on the third step portion 1c of the cylindrical portion 1 and then crimping the upper end of the cylindrical portion 1 inward.

The above components constitute a pressure detector. In such a pressure detector, a moisture-proofing agent is applied to the front and back surfaces of the circuit board 6, and only the area around the wire bonding portion of the circuit board 6 and the storage hole 6a in which the semiconductor chip 5 is stored are formed of a gel resin 17 made of silicon gel. The circuit board 6 and the semiconductor chip 5 are prevented from coming into contact with the atmosphere by being covered with.

This pressure detector is characterized in that a substrate holder 7 is disposed and fixed on the bottom surface of the lower case 3 and a circuit substrate 6 disposed on the base plate 4 is held.
That is, the guide portion 7b1 of the holding portion 7b is connected to the hole 6 of the circuit board 6.
b, and the circuit board 6 is placed on the mounting portion 7b2 of the holding portion 7b.
After that, the circuit board 6 is fixed to the board holder 7 by fixing the land formed around the hole 6b and the protruding portion of the guide 7b1 by soldering. Therefore, even when the pressure detector having this configuration is used under conditions in which a large vibration or impact is applied, the board holder 7 is fixed to the lower case 3 and the circuit board 6 is fixed to the board holder 7. Therefore, only the circuit board 6 does not vibrate, the connection wires for electrically connecting the semiconductor chip 5 and the circuit board 6 are not broken, and the reliability in the electrical connection is improved. .

The gel resin 17 covers only the periphery of the wire bonding portion of the circuit board 6 and the housing hole 6a. This is because when a pressure sensor is used under conditions where large vibrations and shocks are applied, if the gel-like resin is disposed so as to cover the circuit board as in the conventional case, large vibrations and shocks will pass through the gel-like resin. Semiconductor chip 5
Focusing on the fact that the vibration is transmitted to the connection wire connecting the circuit board 6 and the circuit board 6, the gel-like resin 17 is provided only at a necessary portion to suppress the vibration. Therefore, the gel-like resin 1
By arranging only the necessary portions, vibrations and shocks transmitted by the gel resin 17 can be minimized, and the reliability of the electrical connection of the connection wires can be further improved.

The substrate holder 7 also has excellent assemblability in a manufacturing process. As described above, the substrate holder 7 includes the restricting portion 7d and the positioning portion 7b3, and the direction in which the substrate holder 7 is disposed with respect to the lower case 3 is easily determined by the restricting portion 7d. It is arranged so as to coincide with a groove (not shown) corresponding to the regulating portion 7d formed in the lower case 3), and the arrangement direction of the circuit board 7 with respect to the substrate holder 7 is determined by the positioning portion 7b3. In addition, it is possible to prevent a problem such as arranging the circuit board 6 and the board holder 7 in a wrong direction, and to improve the assemblability of the pressure detector.

In the circuit board 6, the position of the hole 6b for holding the guide portion 7b1 of the board holder 7 is set outside the electronic component 13 mounted on the circuit board 6, and
Is formed in the vicinity of the periphery. In the manufacturing process of the pressure detector, the guide portion 7b1 of the board holder 7 is formed around the hole 6b of the circuit board 6 in a state where the circuit board 6 is pressed against the first step portion 1a of the lower case 3. When the hole 6b is formed near the center of the circuit board 6 to be soldered to the land, the circuit board 6 made of a soft material contacts the first step portion 1a of the lower case 3. Of the circuit board 6 may be transmitted to the electronic component 13 which is a semiconductor element disposed therebetween, and may affect the output of the semiconductor chip 5. There is. Therefore, by providing the hole 6b in the vicinity of the peripheral edge of the circuit board 6 in contact with the first step portion 1a of the lower case 3, bending of the circuit board 6 caused by an assembling operation in a manufacturing process is prevented, and 13
To be affected by the bending.

The bonding structure between the circuit board 6 and the substrate holder 7 in the above-described embodiment is such that the guide portion 7b1 of the substrate holder 7 is inserted into the hole 6b of the circuit board 6, and the mounting portion of the substrate holder 7 is placed. After arranging the circuit board 6 on 7b2, the guide portion 7
The circuit board 6 is fixed to the board holder 7 by connecting the protruding portion of b1 to the circuit board 6 by soldering. However, the fixing portion formed on the circuit board of the present invention and the board holder are formed. In the holding portion, for example, the holding portion is a pair of locking pieces (hook) extending from the substrate holder in the direction of the circuit board, and the locking pieces are locking portions (fixing portions formed on the circuit board). By fixing to the (hole), soldering may be unnecessary, and the shapes of the holding portion and the fixing portion of the present invention are not limited to this embodiment.

In the substrate holder 7 of this embodiment, the holding portion 7b is formed integrally with the base portion 7a.
The substrate holder may be configured by a holding unit separate from the base unit.

Further, in this embodiment, the lower case 3 is constituted by the cylindrical portion 1 and the pressure introduction port 2, but a case body integrally provided with the pressure introduction port is adopted, and the structure of the present invention is adopted in this case body. It may be something.

FIG. 1 shows a structure in which the peripheral edge of the circuit board 6 and the lower case 3 are fixed by a silicon-based adhesive. However, the provision of the substrate holder 7 eliminates the adhesive. You can also.

Although the regulating portion 7d of the substrate holder 7 has a protruding shape, for example, a notch is formed in a part of the base portion of the substrate holder, and an arrangement corresponding to the shape of the notch is provided in the case body. A portion may be provided, and the shape of the restricting portion of the present invention is not limited to the present embodiment.

The positioning portion 7b3 of the substrate holder 7
Is configured using the mounting portion 7b2 of the holding portion 7b. However, for example, the positioning portion may be provided exclusively on the base portion of the substrate holder, and the positioning portion of the present invention is not limited to the present embodiment. Absent.

[0043]

[0044]

According to the present invention, the circuit board is provided even if the pressure detector is used under the condition that large vibration or impact is applied by providing the board holder for mounting and fixing the circuit board. There is no disconnection of the connection wires connecting between the semiconductor chip and the semiconductor chip, and the reliability of the electrical connection can be improved.

Further, by providing the substrate holder with the restricting portion and the positioning portion, the assemblability in the manufacturing process can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing a pressure detector according to an embodiment of the present invention.

FIG. 2 is a plan view showing the substrate holder of the embodiment.

FIG. 3 is a side view of the substrate holder.

[Explanation of symbols]

 2 pressure introduction port 3 lower case 5 semiconductor chip 6 circuit board 6a housing hole 6b hole (fixed part) 7 substrate holder 7b holding part 7b1 guiding part 7b2 mounting part 7b3 positioning part 17 gel resin

Claims (5)

(57) [Claims] 1. A case body having a pressure introduction port for introducing a pressure of a medium to be measured, and a casing provided on the pressure introduction port.
A semiconductor chip disposed under the pressure via the base plate, and a storage hole for storing the semiconductor chip.
And is electrically connected to the semiconductor chip.
A circuit board disposed in the case body so as to be located on a base plate, and a substrate holder fixed to the bottom surface of the case body and having a pair of holding portions for holding the circuit board, A pressure detector, comprising: 2. The pressure detector according to claim 1, wherein the substrate holder is provided with a restricting portion for determining an arrangement direction with respect to the case body. 3. A pressure detector according to claim 1 or claim 2, characterized in that it comprises a positioning unit that determines the arrangement direction of the circuit substrate to the substrate holder. 4. A pressure detector according to any of claims 1 to 3, characterized in that by forming a fixing portion corresponding to the holding part near the peripheral edge of the circuit board. 5. A semiconductor device according to claim 1, wherein said circuit board is connected to said semiconductor sensor.
Covers only the area around the ear bonding area and the storage hole
The pressure detector according to any one of claims 1 to 4 , further comprising a gel member .