JPH0821776A - Semiconductor differential pressure sensor - Google Patents

Abstract

PURPOSE:To prevent a fluid to be detected from flowing out from a package when a gauge is broken, by storing a detection gauge for detecting a low pressure of a gas in a plastic package and a detection gauge for detecting a high pressure of a liquid in a can package. CONSTITUTION:The rear surface of a semiconductor substrate 1 of a gauge I for detecting a low pressure of a gas is formed into a thin diaphragm, bonded to a glass stage 2 and attached in a plastic package 4 having a lead frame 3. The rear surface of a semiconductor substrate 1 of a gauge II for detecting a high pressure of a liquid is processed to be a thin diaphragm and bonded to the glass stage 2. Thereafter, the substrate 1 is bonded to a metallic stem 10 having a pipe 8 and a lead pin 9 by a glass of a low melting point, and a metallic cap 11 is welded, thereby, a can package is obtained. Since a package for the gauge II is a can package, even if the diaphragm is broken, a fluid to be detected (gasoline, oil, etc.) never flows outside. At the same time, since the gauge I is a plastic package, the gauge I is manufactured at a low cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle semiconductor type differential pressure sensor for measuring a differential pressure between a gas and a liquid as a detected pressure,
The present invention relates to a semiconductor-type differential pressure sensor that prevents the gauge of a liquid high pressure detection gauge from flowing out of the gauge package even if it breaks.

[0002]

2. Description of the Related Art A conventional semiconductor type differential pressure sensor has
As shown in Japanese Patent No.-3081, two gauge chips were stored in the same can package. Therefore, when the diaphragm of the gauge for liquid high pressure detection is broken, the detected liquid (gasoline, oil, etc.) leaks and vehicle fire occurs. There was a problem.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor differential pressure sensor which does not allow the detection liquid (gasoline, oil, etc.) to flow out of the gauge package even if the diaphragm of the liquid high pressure detection gauge is broken. To supply.

[0004]

According to the present invention, a liquid high pressure detecting gauge is housed in a can package, and a gas low pressure detecting gauge is housed in a plastic package.

[0005]

By using the can package as the liquid high pressure detecting gauge package, even if the diaphragm of the liquid high pressure detecting gauge is broken, it does not flow out of the gauge package. Further, since the gas low pressure detecting gauge is a plastic package, it can be made less expensive than a can package.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a semiconductor type differential pressure sensor according to the present invention will be described with reference to FIGS.

As shown in FIG. 1, a gas low pressure detecting gauge I for measuring a gas pressure such as a manifold pressure is a semiconductor substrate 1
Has a diffusion resistance of, for example, four on its surface, is connected to a bridge by a conductor pattern, and has a connection pad for connection with a circuit board for amplifying a gauge minute voltage. The back surface of the semiconductor substrate 1 is processed into a thin diaphragm shape, bonded to a glass table (or silicon table) 2, and fixed in a plastic package 4 having a lead frame 3 by adhesion. Between the lead frames 3 and the semiconductor substrate 1
Wires 5 connect between the wire bonding pads provided on the surface of the. Then, to protect the conductor pattern, the filler 6
And the plastic cap 7 is adhesively fixed.

On the other hand, the gauge II for high pressure detection of liquids such as gasoline and oil has a diffusion resistance on the surface of the semiconductor substrate 1,
The gauge I is the same as the gauge I described above in that it is wired to the bridge with a conductor pattern and has a connection pad for connecting with a circuit board for amplifying the gauge minute voltage. The back surface of the semiconductor material substrate 1 is processed into a thin diaphragm shape. It is bonded to a glass table (or a silicon table) 2. After that, the pipe 8 and the metal stem 10 having the lead pin 9 are joined with a low melting point glass (or an adhesive, solder, etc.). Wires 5 connect the lead pins 9 and the connection pads.
Further, the metal cap 11 is welded. Gauge I and gauge
The electric signal of II is connected to the substrate on which the amplification circuit is formed, and the potential difference between the gauge I and the gauge II is processed by the differential amplifier 12 to be the sensor output.

A specific structure of the semiconductor pressure sensor will be described with reference to FIG.

A gas low pressure detecting gauge 14 is adhered and fixed to a housing 13 formed of plastic, and an O-ring 16 is attached to a pipe 8 of a liquid high pressure detecting gauge 15 and an assembly is fixed with a screw 17 of the housing 13. . Also, a hybrid integrated circuit 18 having a differential amplifier 12 is also bonded and fixed to the housing 13, and then the gas low pressure detecting gauge 14, the liquid high pressure detecting gauge 15 and the wire 5 from the sensor input / output terminals are hybrid integrated. Connect to Welding Pad on Circuit 18. Then, after the characteristic adjustment, the filling material 6 is injected and cured, and finally the cover 19 is adhesively fixed to the housing 13.

[0011]

According to the present invention, it is possible to supply a semiconductor type differential pressure sensor in which the detection liquid (gasoline, oil, etc.) does not flow out of the gauge package even if the gauge for liquid high pressure detection is broken.

[Brief description of drawings]

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

FIG. 2 is a sectional view of a semiconductor pressure sensor according to an embodiment of the present invention.

[Explanation of symbols]

1 ... Semiconductor substrate, 2 ... Glass base, 3 ... Lead frame,
4 ... plastic package, 5 ... wire rod, 6 ... filling material,
7 ... Plastic cap, 8 ... Pipe, 9 ... Lead pin, 10 ... Metal stem, 11 ... Metal cap, 12 ... Differential amplifier, 13 ... Housing, 14 ... Gas low pressure detection gauge, 15 ... Liquid high pressure detection gauge , 16 ... O-ring, 17 ... Screw, 18 ... Hybrid integrated circuit, 19 ... Cover.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Makoto Yamaguchi 2477, Kashima Yatsu Kashima, Katsuta City, Ibaraki Pref. 3 Hitachi Automotive Engineering Co., Ltd.

Claims (1)

[Claims] 1. A semiconductor substrate having at least two diffusion resistors on the surface thereof, which is wired to a bridge with a conductor pattern, and
Gauge and a liquid for detecting a low gas pressure using a gauge having a connection pad for connecting to a circuit board for amplifying a minute voltage, and further using a gauge in which the back surface of the semiconductor substrate is processed into a thin diaphragm shape. In a semiconductor differential pressure sensor having at least one gauge for detecting high pressure, amplifying the gauge output voltage with a differential amplifier, and using it as a sensor output voltage, the gas low pressure detecting gauge is a plastic package. The semiconductor differential pressure sensor is characterized in that the high liquid pressure detection gauge is housed in a can package.