JPH06102128A - Semiconductor composite function sensor - Google Patents

Abstract

PURPOSE:To obtain a composite function sensor capable of accurately measuring a wide static pressure range by providing a plurality of static pressure detecting parts having different static pressure sensitivities. CONSTITUTION:A sensor consists of a silicon single crystal sensor substrate 1 and the thick part 12 airtightly fixed to a fixing base 2. The central part of the sensor substrate 1 is formed as a thin part 11 and deformed corresponding to the difference between the pressures on both side thereof, that is, differential pressure DELTAP. Differential pressure detecting semiconductor strain gauge group 11 each converting the deformation of the thin part 11 to an electric signal are formed on the thin part 11 by a diffusion method and a temp. detecting semiconductor gauge 121 converting a temp. change to an electric signal is formed to a part of the outer peripheral fixed thick part 12 of the sensor substrate 1. Further, thin parts 13a-13c different in thickness are formed to the outer peripheral fixed thick part 12 of the sensor substrate 1 at three places and static pressure detecting semiconductor gauge groups 131a-131c are formed on the upper surfaces of the thin parts 13a-13c. By thin constitution, a composite function sensor obtaining a highly accurate static pressure output signal over a wide range and measuring difference pressure, temp. and static pressure characteristic with high accuracy is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor multi-function sensor, and more particularly to a semiconductor multi-function sensor having a structure suitable for accurately detecting static pressure.

[0002]

2. Description of the Related Art In a differential pressure transmitter used for flow rate measurement, a gauge resistance is diffused and formed on a semiconductor substrate as a differential pressure sensor for converting a differential pressure into an electric signal, and a pressure sensitive silicon diaphragm having a concave back surface is formed. There is a semiconductor differential pressure sensor having a structure that detects a pressure difference applied to both sides.

Further, the differential pressure transmitter measures the temperature and the static pressure in order to correct the influence of the temperature change and the high pressure (static pressure) applied to both sides of the differential pressure sensor in the differential pressure output signal, and corrects them by an external circuit. Is taken. Specifically, JP-A-60-61637
As shown in No. 6, the semiconductor gauge group that is sensitive to the differential pressure is located on the thin portion of the differential pressure detection silicon diaphragm, and the fixed portion has a static pressure on the thin portion of the static pressure detection silicon diaphragm and the semiconductor gauge group that is sensitive to the temperature. A group of sensitive semiconductor strain gauges is formed. Each detector is designed to obtain the optimum characteristics in the maximum range of use, and the differential pressure, temperature,
Converted to an electrical signal proportional to static pressure, and an external circuit corrects the error in the differential pressure detection signal due to temperature and static pressure.

[0004]

However, the static pressure varies from several kgf / cm ² to several hundred kgf depending on the process conditions used.
Used in a wide range of / cm ^2, and when this pressure range is used with a single detector, the output is small on the low pressure side because of optimum performance at the maximum pressure, and a large error occurs. or,
When the optimum performance is used in the low pressure range, it becomes difficult to use at high pressure, and the problem that the accuracy of static pressure detection is poorer than that of differential pressure detection or temperature detection has been an obstacle to higher accuracy. .

Further, when the plant pressure is to be measured for purposes other than the correction of the differential pressure output, pressure transmitters are used in addition to the differential pressure transmitters for the above-mentioned reasons, and two types of transmitters are used for measurement. Multiple measurements with instruments were desired.

The present invention solves the above-mentioned obstacles and enables a wide static pressure range to be measured with high accuracy, and not only the correction of the differential pressure signal but also the plant pressure can be measured with high accuracy without a pressure transmitter. To provide a multi-function sensor.

[0007]

According to the present invention, there is provided a differential pressure detecting section comprising a semiconductor strain gauge resistance group having a silicon diaphragm section on a one-chip semiconductor substrate, a temperature detecting section comprising a semiconductor gauge resistance in a peripheral fixing section, and dimensions. It consists of a plurality of static pressure detectors consisting of semiconductor strain gauge resistors with silicon diaphragms of different shapes, and a structure that can measure a wide static pressure range with high accuracy by a static pressure detector with different static pressure sensitivity. There is a point.

[0008]

[Function] The back surface is thinly processed on one semiconductor substrate, the semiconductor strain gauge group is diffused on the opposite surface, and the change in gauge resistance value corresponding to the pressure difference applied to both surfaces is converted into an output signal by the bridge circuit connection. The differential pressure detection part and the peripheral fixed part of the structure are diffused, and the gauge resistance value changes in response to temperature changes. , Each of which has a semiconductor strain gauge group diffused on the opposite surface, has different static pressure sensitivity depending on the bridge circuit connection, and can select the optimum static pressure characteristics depending on the type of static pressure such as low pressure and high pressure. It is composed of the static pressure detection unit.

The plurality of static pressure detecting parts differ in the size and shape of the pressure-sensitive diaphragm, and there are one that obtains the highest appropriate sensitivity at high pressure, the one that obtains the most appropriate sensitivity at medium pressure, and the one that obtains the most appropriate sensitivity at low pressure. Highly accurate pressure measurement can be performed by selecting an optimum static pressure detection unit from these in accordance with the static pressure.

[0010]

EXAMPLES The present invention will be described below with reference to the examples shown in FIGS.

FIG. 1 is a top view of an embodiment showing the principle configuration of a multi-function differential pressure sensor of the present invention, and FIG. 2 is a vertical sectional view of FIG.

In FIGS. 1 and 2, reference numeral 1 denotes a silicon single crystal sensor substrate, and a fixed thick portion 12 is airtightly fixed to a fixed base 2.

The central portion of the sensor substrate 1 is formed thin so that it is deformed according to the pressure difference between both sides, that is, the differential pressure ΔP, and the deformation is converted into an electric signal on the thin portion 11. The differential pressure detecting semiconductor strain gauge group 111 is formed by a diffusion method. Further, a temperature detecting semiconductor gauge 121 for converting a temperature change into an electric signal is formed on a part of the outer peripheral fixed thick portion 12 of the sensor substrate 1 by the same diffusion method as the differential pressure detecting semiconductor strain gauge group. Thin-walled portions 13a, 13b, 13c having different thicknesses are formed at three locations on the externally fixed thick-walled portion 12 of the sensor substrate 1, and static pressure detection semiconductor gauge resistors are formed on the upper surfaces of the thin-walled portions 13a, 13b, 13c. Differential pressure across the groups 131a, 131b, 131c,
It is formed by the diffusion method similar to the temperature detection gauge.

The static pressure detecting section 13a is formed in a thin-walled shape to obtain optimum performance for high pressure measurement.
Reference numeral 3b has a thin-walled dimension and shape thinner than the static pressure detection portion 13a, and has an optimal dimension and shape for medium pressure measurement. The static pressure detecting portion 13c is thinner and thinner than the static pressure detecting portion 13b, and is configured to obtain optimum performance for low pressure measurement.

According to the above-described embodiment of the present invention, the static pressure detecting section can be selected, and a highly accurate static pressure output signal can be obtained. Highly accurate multi-function sensor with differential pressure, temperature and static pressure characteristics can be obtained.

[0016]

According to the present invention, by selecting an optimum static pressure sensor, a highly accurate static pressure signal can be obtained over a wide static pressure range, so that the static pressure correction accuracy of the differential pressure detection signal can be improved. It is possible to improve and realize a highly accurate differential pressure sensor in a wide static pressure range.

Further, the plant pressure measurement signal can be measured without using another pressure transmitter, which is a great economical advantage.

Further, it can be easily realized by the same manufacturing process as the conventional semiconductor pressure sensor, and the range of application can be expanded.

[Brief description of drawings]

FIG. 1 is a top view of a semiconductor multi-function sensor according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Silicon single crystal sensor substrate, 2 ... Fixing base, 11 ... Differential pressure detection thin part, 13a ... High pressure static pressure detection thin part, 13b
... Medium pressure static pressure detection thin portion, 13c ... Low pressure static pressure detection thin portion, 111 ... Differential pressure detection semiconductor strain gauge, 112 ... Temperature detection semiconductor gauge, 113a, 113b, 113c ...
Static pressure detection semiconductor strain gauge.

Claims (2)

[Claims] 1. A semiconductor functional sensor having a differential pressure detection unit, a temperature detection unit, and a static pressure detection unit on a semiconductor substrate, wherein the static pressure detection unit has a plurality of static pressure detection units having different pressure sensitivities. Semiconductor multi-function sensor. 2. The semiconductor multi-function sensor according to claim 1, wherein the static pressure detecting portion is formed by forming a pressure sensitive sincone diaphragm having different dimensions in a fixed portion on the outer periphery of the differential pressure detecting silicon diaphragm.