JPH0526983Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a semiconductor pressure sensor.

More specifically, the present invention relates to improving the temperature characteristics and linearity of a semiconductor pressure sensor.

(Prior Art) FIG. 6 is a diagram illustrating the configuration of a conventional example that has been commonly used.

In the figure, reference numeral 1 denotes a sensor chip made of a semiconductor material, in this case made of silicon material, and having a diaphragm portion 11 and a pressure chamber 12. 2 is a piezoresistance gauge provided on the diaphragm portion 11. Reference numeral 3 denotes a semiconductor substrate having a pressure guiding hole 31 communicating with the pressure chamber 12, and is connected to the sensor chip 1 via a low melting point glass 4. Reference numeral 5 denotes a metal pressure guiding pipe whose one end is connected to the pressure guiding hole 21 with an adhesive 6, and in this case, a reference pressure Ps is introduced.

In the above configuration, the pressure impulse chamber 12 has a reference pressure
Ps is introduced, a measurement pressure Pm is applied to the outer surface of the diaphragm portion 11, and a resistance change corresponding to the measurement pressure Pm is obtained from the piezoresistance gauge 2, so that the measurement pressure Pm can be measured.

(Problems to be Solved by the Invention) However, in such a device, since the semiconductor substrate 3 and the metal pressure guiding pipe 5 have different coefficients of thermal expansion, thermal stress is generated due to temperature changes. Thermal stress applies a force that causes disturbance to the semiconductor substrate 3, so it gives a disturbance due to temperature to the semiconductor pressure sensor and deteriorates the temperature characteristics.

The rigidity of the semiconductor substrate 3 and the pressure guiding pipe 5 made of metal are different. Therefore, when pressure is applied from outside the semiconductor pressure sensor and it deforms,
Since the semiconductor substrate 3 and the pressure guiding pipe 5 deform in different ways (semiconductors have lower rigidity and are softer than metals), the semiconductor substrate 3 is different from the pressure guiding pipe 5.
Stress is received from the bonding surface, which causes disturbance and worsens linearity.

The present invention solves this problem.

The purpose of this invention is to have a simple configuration, low cost,
The object of the present invention is to provide a semiconductor pressure sensor with good temperature characteristics and linearity.

(Means for solving the problem) In order to achieve this object, the present invention includes a sensor chip made of a semiconductor, a recess provided in the sensor chip forming a diaphragm, and a piezoresistance gauge provided in the diaphragm. , a semiconductor pressure sensor comprising a substrate attached to the sensor chip and constituting the recess and a pressure chamber, wherein the sensor chip is provided from a side of the substrate on which the sensor chip is attached and a side opposite to the side where the sensor chip is attached. This semiconductor pressure sensor is characterized by having an insulating groove formed in a concentric closed curve on the outside of the mounting surface of the sensor chip to prevent force transmission.

(Function) In the above configuration, when the reference pressure is applied to one side of the diaphragm and the measurement pressure is applied to the other side, the measurement pressure is measured by obtaining a resistance change corresponding to the measurement pressure from the piezoresistive gauge. can do.

Therefore, external thermal stress and stress due to deformation are blocked by the insulating groove and are not transmitted to the sensor chip.

Hereinafter, a detailed explanation will be given based on examples.

(Embodiment) FIG. 1 is an explanatory diagram of the configuration of an embodiment of the present invention.

In the figure, the same symbols as in FIG. 6 indicate the same functions.

Hereinafter, only the differences from FIG. 6 will be explained.

Reference numeral 7 denotes a semiconductor substrate made of silicon material attached to the sensor chip 1. As shown in FIG. 2, 71 is an insulating groove provided on the substrate 7 and arranged concentrically around the sensor chip 1 to prevent the transmission of force. The insulating groove 7 is formed in the semiconductor substrate 7 by etching or the like. The thickness of the portion of the semiconductor substrate 7 where the insulating groove 7 is formed is made thicker than the thickness of the diaphragm portion 11 so as not to reduce the sensitivity of the diaphragm portion 11. Reference numeral 8 denotes a housing made of ceramic or the like fixed to the outer edge of the semiconductor substrate 7.

In the above configuration, the pressure chamber 12 has a reference pressure Ps
is introduced, a measurement pressure Pm is applied to the outer surface of the diaphragm portion 11, and a resistance change corresponding to the measurement pressure Pm is obtained from the piezoresistance gauge 2, so that the measurement pressure Pm can be measured.

Therefore, when a temperature change such as a change in ambient temperature occurs, the sensor chip 1 and the semiconductor substrate 7 have the same coefficient of thermal expansion since they are made of silicon material. Therefore, the sensor chip 1 and the semiconductor substrate 7 are not subjected to thermal stress due to temperature changes. Further, it is desirable that the semiconductor substrate 7 and the housing part 8 have as close a coefficient of thermal expansion as possible, but due to insulation, cost, etc., it is necessary to use materials with different coefficients of thermal expansion, such as ceramics. . In this case, thermal stress is generated between the semiconductor substrate 7 and the housing portion 8 due to the difference in coefficient of thermal expansion. This thermal stress
1. Therefore, this thermal stress is not transmitted to the sensor chip 1.

Next, the housing portion 8 is bent due to the measurement pressure Pm, but as shown in FIG.
This transformation is not transmitted. On the other hand, since the sensor chip 1 and the semiconductor substrate 2 are made of the same material, they have the same rigidity and the same deformation behavior.

As a result, thermal stress caused by changes in ambient temperature or the like or deformation due to measurement pressure is alleviated by the insulating groove 71, so that a semiconductor pressure sensor with good temperature characteristics and good linearity can be realized. Moreover, since basically only the insulating groove 71 needs to be provided, a semiconductor pressure sensor with a simple structure and high reliability can be obtained.

FIG. 4 is an explanatory diagram of the main part configuration of another embodiment of the present invention.

In this embodiment, a plurality of insulating grooves 71 are provided on both sides of the semiconductor substrate 7.

FIG. 5 is an explanatory diagram of the main part configuration of another embodiment of the present invention.

In this embodiment, a plurality of insulating grooves 71 are provided on one side of the semiconductor substrate 7.

Note that in the above embodiment, the semiconductor substrate 7
Although it has been described that the housing portion 8 is bonded with an adhesive, the present invention is not limited to this, and of course, for example, a eutectic alloy, glass, etc. may be used.

Further, the material of the semiconductor substrate 7 does not need to be the same as that of the sensor chip 1, and it is sufficient if the material has a coefficient of thermal expansion and a modulus of rigidity close to that of the sensor chip 1.

Further, the insulating groove 71 is not limited to being formed by etching, and may of course be formed by, for example, machining.

(Effects of the Invention) As explained above, the present invention includes a sensor chip made of a semiconductor, a recess provided in the sensor chip forming a diaphragm, a piezoresistance gauge provided in the diaphragm, and a piezoresistance gauge attached to the sensor chip. In a semiconductor pressure sensor comprising a recess and a substrate constituting a pressure chamber, the sensor chip is attached from a side of the substrate on which the sensor chip is attached and a side opposite to the side where the sensor chip is attached, and the sensor chip is attached around the sensor chip. A semiconductor pressure sensor is constructed, which is characterized by having an insulating groove provided outside the surface in a concentric closed curve shape to prevent force transmission.

As a result, (1) thermal stress caused by changes in ambient temperature or the like or deformation due to measurement pressure is alleviated by the insulating grooves, so it is possible to realize a semiconductor pressure sensor with good temperature characteristics and good linearity.

(2) Since it is only necessary to provide insulation grooves on the board,
The structure is simple.

(3) Since the insulation groove is provided from the side of the board on which the sensor chip is attached and the side opposite to the side on which the sensor chip is attached, force insulation is ensured and a highly reliable semiconductor pressure sensor can be obtained. It will be done.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of the configuration of one embodiment of the present invention;
The figure is an explanatory diagram of the main part configuration of FIG. 1, FIG. 3 is an explanatory diagram of the operation of FIG. 1, FIG. 4 is an explanatory diagram of the main part configuration of another embodiment of the present invention, and FIG. FIG. 6 is a diagram illustrating the configuration of a conventional example that has been generally used. 1... Sensor chip, 11... Diaphragm section, 12... Pressure conduction section, 2 Piezo resistance gauge, 31
... Pressure conducting hole, 4 ... Low melting point glass, 6 ... Adhesive, 7 ... Semiconductor substrate, 71 ... Insulating groove, 8 ...
Housing part.

Claims (1)

[Claims for Utility Model Registration] A sensor chip made of a semiconductor, a recess provided on the sensor chip forming a diaphragm, a piezoresistance gauge provided on the diaphragm, and a piezoresistance gauge attached to the sensor chip forming a pressure chamber with the recess. A semiconductor pressure sensor comprising a substrate, the semiconductor pressure sensor having a concentric closed curved line extending from the sensor chip mounting surface side of the substrate and the opposite surface of the sensor chip mounting surface side, with the sensor chip as the center and outward from the sensor chip mounting surface. 1. A semiconductor pressure sensor characterized by having an insulating groove provided in the groove to prevent force transmission.