JPH09257615A - Semiconductor pressure sensor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an oil sealing ball from dropping by effectively mounting a diaphragm, jointing its circumference to lower a spring constant, controlling internal pressure and furthermore providing an oil sealing part in a pipe line. SOLUTION: A semiconductor sensor is constituted in a manner that a semiconductor sensor chip 1 is mounted on the recess part 2-1 of a metal piece 2, oil of a pressure transmission medium is filled, the upper part thereof is sealed with a diaphragm 3 and a protection cover 4 is covered. The diaphragm 3 is set in the recess part 2-1 of the metal piece 2, thereafter the protection cover 4 is pressure-fitted and fixed, and finally the semiconductor pressure sensor is manufactured by fixing a pressure fitting part by welding.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a construction machine, an industrial machine, an automobile,
The present invention relates to a semiconductor pressure sensor used for pressure measurement of oil such as semiconductors and foods, air, semiconductor gas and other fluids.

[0002]

2. Description of the Related Art Conventionally, the welded portion is located inside the press-fitting end portion. The problem is that the operating range of the diaphragm is reduced, the spring constant is increased, the internal pressure of the enclosed oil is increased, and the pressure characteristics are affected. In addition, conventionally, the sealed portion of oil is located outside the pressure pipe, and when this portion is broken, there arises a problem that the pressure-measuring medium flows out to the outside.

[0003]

[Object of the invention]

(2) An object of the present invention is to improve a method for manufacturing a semiconductor pressure sensor for increasing the pressure of the oil-sealed pressure sensor (50 MPa or more) and reducing the cost. At the same time, it is an object to provide a semiconductor pressure sensor for high voltage manufactured by this manufacturing method.

[0004]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention, in which 1 is a pressure sensor chip, 2 is a metal piece, 2-1 is a recess, 2-2 is an oil filling hole, 3 is a diaphragm, and 4 is a protective cover. 5 is a sealing oil, 6 is a sealing ball, 7 is a hermetic seal, 8 is a signal wire, and 9 is a welded portion.

Next, the manufacturing process is shown in FIG. FIG. 2 (a)
, The pressure sensor chip 1 is placed in the recess 2-2 of the metal piece 2.
Adhesively fixed. The signal line is pulled out by a hermetically sealed
The signal wire 8 is bonded to the lead portion of the rule 7.

Next, as shown in FIG. 2B, the diaphragm 3 is dropped into the upper step of the recess 2-1. Further, the cover-4 is placed on top, set on a jig, and the cover-4 is press-fitted and temporarily fixed.

Next, as shown in FIG. 2 (c), the press-fitting portion (the boundary line between the metal piece 2 and the cover 4) is welded 9 to integrate the diaphragm 3 and the cover 4 on the metal piece 2.

Since the structure is constructed by such a manufacturing method, the operating range of the diaphragm 3 can be used to the maximum extent. As a result, the spring constant of the diaphragm 3 can be reduced, and the internal pressure due to the heat of the sealing oil 5 can be suppressed,
The characteristics of the pressure sensor chip 1 can be improved.

Further, the oil sealing hole 2-2 shown in the metal piece 2 is
Since it is located in the same introducing pipe as the medium to be measured (3), the force for pushing the sealing ball 6 (pressure of the medium to be measured) and the force applied from the diaphragm 3 are transmitted to the sealing oil 5, The force for pushing the sealing ball 6 outward is the same. With such a structure, the sealing ball 6 is stable because the external pressure and the internal pressure are maintained at a constant force with a good balance.

[0010]

[Explanation of Effect] The semiconductor pressure sensor can be miniaturized, and in particular, it can be further miniaturized by improving the characteristics of the diaphragm. Further, the connection portion can be made small, and a high-pressure type oil-sealed semiconductor pressure sensor can be realized. It is an oil-sealing type semiconductor pressure sensor, and improving the reliability of the oil-sealing method is an important factor, and a semiconductor pressure sensor that can respond to this can be realized.

[Brief description of drawings]

FIG. 1 is an external structural view of an oil-sealed semiconductor pressure sensor of the present invention.

FIG. 2 is a diagram showing a manufacturing process of the oil-sealed semiconductor pressure sensor of the present invention.

[Explanation of symbols]

 1 Semiconductor Pressure Sensor Chip 2 Metal Piece 2-1 Recess (Concave Processed into Metal Piece) 2-2 Oil Filling Hole 3 Diaphragm 4 Protective Cover 5 Oil Seal Oil 6 Oil Seal Ball 7 Hermetic Seal 8 Signal Wire (4) 9 Weld

Claims (3)

[Claims] 1. A semiconductor pressure sensor comprising a semiconductor pressure sensor chip mounted in a recess of a metal piece, oil as a pressure transmission medium sealed therein, and a diaphragm covering the oil, which is covered with a protective cover. A method of manufacturing a semiconductor pressure sensor, comprising: dropping the diaphragm into a recess of the metal piece, then press-fitting the protective cover to temporarily fix the press-fitting portion, and fixing the press-fitting portion by welding. 2. The method of manufacturing a semiconductor pressure sensor according to claim 1, wherein the oil of the pressure transmission medium interposed in the space covered with the metal piece and the diaphragm has the same pressure as the pressure of the fluid to be measured. A method for manufacturing a semiconductor pressure sensor, characterized in that the semiconductor pressure sensor is encapsulated as follows. 3. A semiconductor pressure sensor manufactured by the manufacturing method according to claim 1.