JPS60219529A - Semiconductor type pressure sensor - Google Patents

Abstract

PURPOSE:To obtain a pressure sensor such that a plurality of absolute pressures are outputted while amplified and receives temp. compensation, by including a plurality of semiconductor chips in the same reference pressure chamber along with a peripheral circuit parts. CONSTITUTION:A wiring printed circuit board 6, to which chips 3, 4 each having a pressure-sensitive diaphragm and peripheral circuit part 5 are really mounted, is received in a reference pressure chamber consisting of a bottom plate 1 and a lid 2. The pressure-sensitive chips 3, 4 have resistance elements, diffusion regions, electrodes and wiring in the flat surface sides of the upper surfaces thereof and the peripheral parts thereof in the opposite side are supported through pressure guide pipes 7, 8 and spacers 9, 10 for relieving heat strain from said pipes 7, 8. The pipes 7, 8 penetrate through the bottom plate 1 in an airtight state. The bridges on the upper surfaces of the chips 3, 4 are connected to the peripheral circuit part 5 through lead wires 11 and the circuit part 5 are connected to the power source terminal 13, an earth terminal 14 and output terminals 15, 16 piercing through the bottom plate 1 through insulating substances 12 in an airtight manner by lead wires 17. The output signals of the chips 3, 4 are amplified and receives temp. adjustment by the circuit part 5 and led out from the terminals 15, 16 and the common earth terminal 14.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a semiconductor pressure sensor for measuring a plurality of absolute pressures using a semiconductor pressure-sensitive diaphragm.

[Prior art and its problems]

When a plurality of absolute pressures are measured using a semi-solid pressure sensor having a semiconductor pressure-sensitive diaphragm, a corresponding number of pressure sensors must be used. Also,
When measuring differential pressure, it is necessary to protect the electrode provided on one side of the diaphragm from corrosion, so it is usually not done to introduce two pressures to both sides of the diaphragm, and the electrode side is kept in a vacuum or inert gas. It is common to use two absolute pressure sensors with a pressure reference chamber that is satisfied. Furthermore, since the output signal from the electrode of the pressure-sensitive diaphragm is small, it is necessary to amplify it and perform temperature compensation, and when a plurality of pressure sensors are used, the number of connections with these peripheral circuits increases accordingly.

[Purpose of the invention]

In contrast, it is an object of the present invention to provide a single semiconductor pressure sensor that outputs two or more absolute pressures after being amplified and temperature compensated.

[Key points of the invention]

The present invention provides the following features: - One surface of a semiconductor substrate of a conductivity type is formed thinner at the center than at the periphery, and a plurality of resistive element regions of other conductivity types provided on the other side of the center portion form a bridge. A plurality of pressure-sensitive chips are housed in an airtight container, the periphery of the pressure-sensitive chips is hermetically coupled to the end face of a tube that hermetically passes through the container, and an amplification circuit section and a temperature compensation circuit section for the output of the bridge are connected. The above purpose is achieved by having the common power supply terminal, the common ground terminal, and the output terminal of each pressure-sensitive chip, which are housed in the container and are insulated from the container and each other, drawn out of the container. It is something to be achieved.

[Embodiments of the invention]

FIGS. 1 and 2 show the structure of an embodiment of the present invention, including steps 3 and 4 having a pressure-sensitive diaphragm in a reference pressure chamber consisting of a bottom plate 1 and a lid 2, and the surroundings indicated schematically by dotted lines in FIG. A wiring board 6 on which a circuit section 5 is mounted is also accommodated. The reference pressure chamber is evacuated or filled with inert gas. The pressure sensitive chip 3゜4 has a resistive element, a diffusion region, and
It has electrodes and wiring, and its peripheral edge on the opposite side is supported via the pressure impulse tubes 7 and 8 and a spacer 9.10 made of the same semiconductor as the chip for alleviating thermal strain from the pressure impulse tubes. The pressure impulse tubes 7 and 8 hermetically penetrate the bottom plate 1 ◇Pressure sensitive chip 3
, 4, the resistive element bridge on the top surface is conductive! It is connected to the peripheral circuit section 5 via fMll, and the peripheral circuit section 5 is connected to the bottom plate 1.
A power supply terminal 13. is passed through the insulator 12 through I- in an airtight manner.
The ground terminal 14 is connected to the output terminal 15, 16 by a conductor 17. The output signal of the pressure sensitive chip 3.4 is amplified and temperature adjusted by the peripheral circuit section, and the output signal is output to the output terminal 15°1.
6 and the common ground terminal 14. This allows the two measuring pressures introduced independently from the impulse lines 7 and 8 to be detected separately from these terminals. single-
When measuring these pressures using two pressure sensors, each has an output terminal, a power supply terminal, and a ground terminal, so the total number of terminals is six, but in this example, the number of terminals is six. Since only four are required, the number of connections is reduced. If more pressure sensitive chips are housed in the same standard pressure chamber, the reduction in the number of terminals will be even greater. Also, sensitivity adjustment, level adjustment, temperature compensation, etc. for each pressure-sensitive step! Being able to perform the 1111 adjustment process at the same time and rationalizing the adjustment process has a large and effective effect on cost reduction. Note that when measuring the differential pressure between two pressures, it is effective to also accommodate the differential circuit within the reference pressure chamber.

〔Effect of the invention〕

The present invention has a configuration in which a plurality of pressure-sensitive semiconductor chips are included in a standard pressure chamber together with peripheral circuitry, and only one bottom plate, lid, etc. are required to constitute the standard pressure chamber, and the power terminal, Since the ground terminal can be shared and only one output terminal is required for each pressure-sensitive chip, the number of terminals is small, and the adjustment process can be streamlined, making it possible to construct a compact and economical pressure sensor for multi-point measurement. It has become possible. Also electrical connections,
The peripheral circuit section is also included in the airtight reference pressure chamber, and this reference pressure chamber is either evacuated or filled with inert gas, allowing highly reliable semiconductor-type pressure with no risk of corrosion of resistive elements, electrodes, wiring, etc. It can be used extremely effectively as a sensor to measure a plurality of absolute pressures or to measure the differential pressure between those pressures.

[Brief explanation of the drawing]

FIG. 1 is a top view of the internal structure of a pressure sensor according to an embodiment of the present invention, and FIG. 2 is a sectional view thereof. 1... Bottom plate, 2... Lid, 3, 4...
...Pressure sensitive tip, 5...Peripheral circuit section, 6...
...Wiring board, 7,8... Impulse tube, 11.
17...Conductor wire, 13...Power terminal, 1
4... Ground terminal, 15.16... Output terminal.

Claims (1)

[Claims] 1) - A pressure-sensitive chip in which the central part of one surface of a conductive type semiconductor substrate is formed thinner than the peripheral part, and a plurality of resistive elements of other conductive types provided on the other side of the central part constitute a bridge. A plurality of pressure sensitive chips are housed in an airtight container, the peripheral portion of the pressure sensitive chip is hermetically coupled to the end face of a tube that hermetically passes through the container, and an amplification circuit section and a temperature compensation circuit section for the output of the bridge are also housed in the container. A semiconductor pressure sensor, which is housed in a container, and has a common power terminal, a common ground terminal, and an output terminal of each pressure-sensitive chip, which are insulated from the circuit portion, the container, and each other, and are drawn out of the container. .