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MEMS polysilicon nanofilm pressure sensor chip and manufacturing method thereof

A pressure sensor, polysilicon technology, applied in fluid pressure measurement by changing the ohmic resistance, measurement of the property force of the piezoelectric resistance material, etc., can solve the problems of low sensitivity ratio, good temperature characteristics, and thin pressure-sensitive film, etc. Achieve the effect of improving sensitivity, high linearity and improving linearity

Inactive Publication Date: 2016-04-13
SHENYANG INSTITUTE OF CHEMICAL TECHNOLOGY
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] (1) Due to the small size of the surface micromechanical pressure sensor and the thin pressure-sensitive film, the linearity is slightly poor;
[0010] (2) Surface micromechanical pressure sensors usually use ordinary polysilicon thin films as force sensitive resistors. Compared with diffused silicon, they have good temperature characteristics but low sensitivity ratio

Method used

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  • MEMS polysilicon nanofilm pressure sensor chip and manufacturing method thereof
  • MEMS polysilicon nanofilm pressure sensor chip and manufacturing method thereof
  • MEMS polysilicon nanofilm pressure sensor chip and manufacturing method thereof

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Embodiment 1

[0039] The present invention is a kind of MEMS polysilicon nano film pressure sensor chip, as figure 1 and figure 2 shown in . The sensor includes: a single crystal silicon substrate 1; on the single crystal silicon substrate 1, a pressure sensitive film 4 with a flat cross-section is arranged, with a film thickness of 3 μm and an area of ​​200 μm×100 μm; the pressure sensitive film 4 and the single crystal silicon substrate The bottom 1 is connected to form a closed cavity 2 between the two, and the height of the cavity is 1 μm; there are corrosion holes 3 around the edge of the pressure sensitive film 4, and after the sacrificial layer is etched and removed, it is sealed with polysilicon to form an approximate vacuum cavity; Four force-sensitive resistors 5 are arranged on the pressure film 4, and the force-sensitive resistors are P-type polysilicon nano-films; the four force-sensitive resistors 5 are connected by metal wires 6 to form a Wheatstone bridge, which converts p...

Embodiment 2

[0041] The present invention proposes a method for preparing a MEMS polysilicon nano-membrane pressure sensor chip, comprising the following steps:

[0042] (1) image 3 Shown is the first thermal oxidation process. Deposit 0.2 μm thick silicon nitride on the single crystal silicon substrate by plasma enhanced chemical vapor deposition (PECVD) as a mask layer, then thermally oxidize and grow 1 μm thick silicon dioxide, and use phosphoric acid and hydrofluoric acid to remove the nitride respectively. Silicon and silicon dioxide, forming grooves with a depth of 0.5 μm on the silicon wafer.

[0043] (2) Figure 4 Shown is the second thermal oxidation process. Step (1) was repeated to form stepped grooves with two depths of 0.5 μm and 1 μm on the silicon wafer.

[0044] (3) Figure 5 Shown is the process of depositing the first layer of polysilicon. Use PECVD to deposit silicon dioxide in the groove, and use low pressure chemical vapor deposition (LPCVD) to deposit 1 μm thic...

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Abstract

The invention provides a MEMS polysilicon nanofilm pressure sensor chip and a manufacturing method thereof, and relates to a sensor chip and a manufacturing method thereof. The sensor includes a monocrystalline silicon substrate (1), a pressure sensing film (4) having the section of a flat polysilicon is arranged on the silicon substrate, an enclosed cavity (2) is formed between the pressure sensing film and the substrate by taking silica as a sacrificial layer, the upper surface of the pressure sensing film (4) is provided with four polysilicon nanofilm force sensing resistors (5), the four polysilicon nanofilm force sensing resistors (5), the pressure sensing film (4), and metal leads are isolated by insulation layers (7), the four force sensing resistors (5) are connected to form a Wheatstone bridge via the metal leads to convert the pressure to voltage to output, and sealed corrosion holes (3) are arranged outside the edge of the pressure sensing film (4). The sensor preparing method is compatible with integrated circuit technology and is easy to integrate. The sensor has the characteristics of high linearity sensitivity, wide operational temperature range, high overload capability, easy integration, and low cost.

Description

technical field [0001] The invention relates to a sensor chip and a manufacturing method thereof, in particular to a MEMS polysilicon nano-membrane pressure sensor chip and a manufacturing method thereof. Background technique [0002] MEMS (Micro-Electro-Mechanical Systems) pressure sensor is a sensor prepared by integrated circuit technology and micro-machining technology by using the piezoresistive effect and good elasticity of semiconductor materials. With the advantages of small size and high sensitivity, it is one of the most widely used sensors. MEMS pressure sensors are mainly divided into capacitive and piezoresistive. Due to the complex process and high process stability requirements of the capacitive type, more than 90% of the world's MEMS pressure sensors are silicon piezoresistive. [0003] Silicon piezoresistive pressure sensors are divided into two types according to the processing technology: bulk silicon micromachining and surface micromachining. Bulk silic...

Claims

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Application Information

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IPC IPC(8): G01L1/18G01L9/06
CPCG01L1/18G01L9/06
Inventor 王健揣荣岩
Owner SHENYANG INSTITUTE OF CHEMICAL TECHNOLOGY
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