MEMS capacitive sensor and preparation method thereof

A technology of capacitive and pressure sensors, which is applied in fluid pressure measurement using capacitance changes, piezoelectric/electrostrictive/magnetostrictive devices, televisions, etc., can solve complex manufacturing processes, poor reliability, MEMS capacitive pressure sensors Poor linearity and other problems, to achieve the effect of low cost, high consistency, high linearity

Active Publication Date: 2020-12-25
NANJING GAOHUA TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the capacitance value is inversely proportional to the electrode spacing, the corresponding MEMS capacitive pressure sensor has the disadvantage of poor linearity
In addition, the fixed electrodes of the existing MEMS capacitive pressure sensors are usually enclosed in the cavity, and the electrodes of the fixed electrodes need to be drilled, filled, polished and other steps to realize the electrode extraction of the fixed electrodes. The preparation process is complicated and the reliability is poor.

Method used

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  • MEMS capacitive sensor and preparation method thereof

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Experimental program
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Effect test

Embodiment 1

[0037] Such as figure 1 As shown, the MEMS capacitive pressure sensor proposed by the present invention includes a stacked first substrate 4 and a second substrate 7;

[0038] A pressure-sensitive film 1 is formed on the upper surface of the first substrate 4; a first groove 3 is formed on the lower surface of the first substrate 4 opposite to the pressure-sensitive film 1 by etching;

[0039] A dielectric block 2 is arranged on the lower surface of the pressure sensitive film 1, and the dielectric block 2 is located in the first groove 3;

[0040] The second groove 8 is arranged on the upper surface of the second substrate 7, and forms a vacuum chamber 12 with the first groove 3;

[0041] The third groove 9 and the fourth groove 10 are arranged on the lower surface of the second substrate 7 surrounding and spaced apart from the second groove 8;

[0042] an insulating layer 11 covering the lower surface of the second substrate 7;

[0043] The first electrode 5 is disposed o...

Embodiment 2

[0060] The present invention also proposes a preparation method of a MEMS capacitive pressure sensor, specifically, the preparation method comprises the following steps:

[0061] a. Select an N-type (100) single crystal silicon wafer with a thickness of 500mm as the first substrate 4, and obtain a first groove 3 with a depth of, for example, 480 μm and a thickness of 20 μm by photolithography and KOH anisotropic wet etching The pressure sensitive membrane 1;

[0062] b. Install a dielectric block 2 on the lower surface of the pressure sensitive membrane 1 by assembling, the dielectric block 2 is, for example, a barium titanate ceramic block, and its size is, for example: length´width´height=200μm´200μm´600μm;

[0063] c. Select a 500mm thick N-type (100) single crystal silicon wafer as the second substrate 7, and carry out photolithography and KOH anisotropic wet etching on the upper surface of the second substrate 7 to obtain a depth of, for example, 400 μm, a second groove ...

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Abstract

The invention provides an MEMS capacitive pressure sensor and a preparation method thereof. The MEMS capacitive pressure sensor comprises a first substrate and a second substrate which are stacked, apressure sensitive film which is arranged on the upper surface of the first substrate, a first groove which is formed in the lower surface of the first substrate and is opposite to the pressure sensitive film, a dielectric block which is arranged on the lower surface of the pressure sensitive film and is positioned in the first groove, a second groove which is formed in the upper surface of the second substrate, and with a vacuum cavity with the first groove, a third groove and a fourth groove which surround and are arranged on the lower surface of the second substrate at an interval of the second groove, an insulating layer which is arranged on the lower surface of the second substrate, a first electrode which is arranged on the insulating layer, close to the side wall of the second groove, of the third groove, and a second electrode which is arranged on the insulating layer, adjacent to the side wall of the second groove, of the fourth groove. The sensor has higher linearity, and theelectrode leading-out reliability of the sensor is improved.

Description

technical field [0001] The invention relates to the field of MEMS, in particular to a MEMS capacitive pressure sensor and a preparation method thereof. Background technique [0002] The pressure sensor is mainly used to measure the environmental pressure. It has been developed for many years. It is widely used in the fields of national defense, military, industry, agriculture and medical treatment. It is currently the most common type of sensor. MEMS pressure sensors mainly include MEMS piezoresistive pressure sensors and MEMS capacitive pressure sensors. Compared with MEMS piezoresistive pressure sensors, MEMS capacitive pressure sensors have advantages such as small temperature drift, so they are favored by people. Existing MEMS capacitive pressure sensors are mainly composed of fixed electrodes, movable electrodes and a cavity. Under the action of environmental pressure, the distance between the capacitive electrodes changes, which in turn causes the capacitance value to...

Claims

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Application Information

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IPC IPC(8): B81B7/02B81C1/00G01L1/14G01L9/12
CPCB81B7/02B81B2201/0264B81C1/00015G01L1/148G01L9/12
Inventor李维平崔艳凤兰之康
OwnerNANJING GAOHUA TECH