CN111141443A - A Capacitive Thin Film Vacuum Gauge Based on MEMS Technology - Google Patents
A Capacitive Thin Film Vacuum Gauge Based on MEMS Technology Download PDFInfo
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- CN111141443A CN111141443A CN201911362566.8A CN201911362566A CN111141443A CN 111141443 A CN111141443 A CN 111141443A CN 201911362566 A CN201911362566 A CN 201911362566A CN 111141443 A CN111141443 A CN 111141443A
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- pressure
- lower substrate
- electrode
- vacuum gauge
- film
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- 238000005516 engineering process Methods 0.000 title claims abstract description 16
- 239000010409 thin film Substances 0.000 title claims description 5
- 239000000758 substrate Substances 0.000 claims abstract description 58
- 239000010408 film Substances 0.000 claims description 49
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 15
- 239000011521 glass Substances 0.000 claims description 15
- 229910052710 silicon Inorganic materials 0.000 claims description 15
- 239000010703 silicon Substances 0.000 claims description 15
- 238000007789 sealing Methods 0.000 claims description 9
- 238000000034 method Methods 0.000 claims description 7
- 238000005530 etching Methods 0.000 claims description 2
- 230000035945 sensitivity Effects 0.000 abstract description 12
- 238000005259 measurement Methods 0.000 abstract description 6
- 230000008859 change Effects 0.000 abstract description 4
- 238000005265 energy consumption Methods 0.000 abstract description 4
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 4
- 229910052796 boron Inorganic materials 0.000 description 4
- 238000000605 extraction Methods 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- RZVAJINKPMORJF-UHFFFAOYSA-N Acetaminophen Chemical compound CC(=O)NC1=CC=C(O)C=C1 RZVAJINKPMORJF-UHFFFAOYSA-N 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000005297 pyrex Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 238000013461 design Methods 0.000 description 2
- 239000003990 capacitor Substances 0.000 description 1
- 238000012938 design process Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910021421 monocrystalline silicon Inorganic materials 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
Images
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
- G01L9/12—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in capacitance, i.e. electric circuits therefor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L13/00—Devices or apparatus for measuring differences of two or more fluid pressure values
- G01L13/06—Devices or apparatus for measuring differences of two or more fluid pressure values using electric or magnetic pressure-sensitive elements
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L21/00—Vacuum gauges
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Fluid Pressure (AREA)
Abstract
本发明公开了一种基于MEMS技术的电容薄膜真空计，基于MEMS技术，待测环境中气压的变化使感压薄膜产生位移，引起下基板电极与感压薄膜之间距离发生变化，从而改变了感压薄膜电极与下基板电极之间的电容值，通过测量电容值的大小即可得到待测环境的真空度，本发明能够显著降低真空计的尺寸和能耗，同时，通过根据测量需要使用不同参数的感压薄膜能够有效提高测量的灵敏度。
The invention discloses a capacitance film vacuum gauge based on MEMS technology. Based on the MEMS technology, the change of air pressure in the environment to be measured causes the pressure-sensitive film to shift, causing the distance between the lower substrate electrode and the pressure-sensitive film to change, thereby changing the The capacitance value between the pressure-sensitive film electrode and the lower substrate electrode can be measured by measuring the capacitance value to obtain the vacuum degree of the environment to be measured. The present invention can significantly reduce the size and energy consumption of the vacuum gauge. Pressure-sensitive films with different parameters can effectively improve the sensitivity of the measurement.
Description
Technical Field
The invention belongs to the technical field of vacuum measurement, and particularly relates to a capacitive film vacuum gauge based on an MEMS (micro-electromechanical system) technology.
Background
The miniaturization of vacuum gauges has led to a dramatic advance in order to meet field testing and space detection requirements. The MEMS sensor has the characteristics of miniaturization, low cost, high performance, easy compatibility with a CMOS integrated circuit and the like. Among the different types of MEMS sensors, the most common and widely used are piezoresistive and capacitive sensors, wherein capacitive sensors have the advantages of high sensitivity, low temperature coefficient, low power consumption, etc., compared to piezoresistive sensors. The MEMS capacitance film vacuum gauge is one of MEMS capacitance sensors, can meet the application requirements of the fields of deep space exploration, aerodynamic research, near space exploration and the like on high measurement accuracy, small volume, light weight and low power consumption of a vacuum measurement instrument, and has wide application prospect. However, the MEMS capacitive film vacuum gauge in the prior art mainly has the problems of high size and energy consumption, low sensitivity, and the like.
Disclosure of Invention
In view of this, the present invention provides a capacitance film vacuum gauge based on the MEMS technology, which can realize a vacuum gauge with a small size, low energy consumption, and high sensitivity.
The invention provides a capacitance film vacuum gauge based on an MEMS (micro-electromechanical system) technology, which comprises an upper substrate 7, a lower substrate 8, a silicon chip 1 and a glass sealing tube 4; the silicon chip 1 is provided with a pressure sensing film 10 and an electrode leading-out hole A5; the upper substrate 7 and the lower substrate 8 are made of glass, the upper surface of the lower substrate 8 is plated with a lower substrate electrode 2, the upper substrate 7 is provided with a vent hole 9 and an electrode leading-out hole B6, and the position of the vent hole 9 is aligned with the position of the pressure-sensitive film 10; the electrode of the lower substrate 8 is led out to the upper surface of the upper substrate 7 through an electrode lead-out hole A5 and an electrode lead-out hole B6; the electrode of the pressure-sensitive film 10 is led out to the upper surface of the upper substrate 7 through the electrode lead-out hole B6; the silicon chip 1 is respectively bonded with the lower surface of the upper substrate 7 and the upper surface of the lower substrate 8, the glass sealing tube 4 is hermetically buckled on the vent hole 9, and a sealed vacuum cavity is formed between the pressure sensing film 4 and the vent hole 9 of the upper substrate 7 and the upper surface of the lower substrate 9;
and placing the vacuum gauge in a vacuum environment to be measured, removing the glass sealing tube 4, and measuring the capacitance value between the electrode of the lower substrate 8 and the electrode of the pressure sensing film 1 to obtain the vacuum degree of the vacuum environment to be measured.
Further, the pressure-sensitive film 1 is obtained by etching the silicon wafer by adopting a concentrated boron doping method.
Further, the pressure-sensitive film 1 had a side length of 5mm and a thickness of 16 μm.
Has the advantages that:
based on the MEMS technology, the pressure sensing film is displaced due to the change of air pressure in the environment to be measured, so that the distance between the lower substrate electrode and the pressure sensing film is changed, the capacitance value between the pressure sensing film electrode and the lower substrate electrode is changed, the vacuum degree of the environment to be measured can be obtained by measuring the capacitance value, the size and the energy consumption of the vacuum gauge can be obviously reduced, and meanwhile, the pressure sensing film with different parameters can be used according to the measurement requirement, so that the measurement sensitivity can be effectively improved.
Drawings
Fig. 1 is a schematic structural diagram of a capacitance film vacuum gauge based on the MEMS technology provided in the present invention.
Fig. 2 is a schematic diagram of a silicon wafer structure of a capacitance thin film vacuum gauge based on the MEMS technology.
Fig. 3 is a schematic view of a lower substrate structure of a capacitance thin film vacuum gauge based on the MEMS technology.
Fig. 4 is a schematic structural diagram of an upper substrate of a capacitance thin film vacuum gauge based on the MEMS technology.
The structure comprises a silicon chip 1, a lower substrate electrode 2, an extraction electrode 3, a glass sealing tube 4, an electrode extraction hole 5, an electrode extraction hole B6, an upper substrate 7, a lower substrate 8, a vent hole 9, a pressure sensing film 10 and an electrode lead 11.
Detailed Description
The invention is described in detail below by way of example with reference to the accompanying drawings.
The invention provides a capacitance film vacuum gauge based on an MEMS (micro-electromechanical system) technology, as shown in figure 1, the capacitance film vacuum gauge is of a three-layer structure as a whole, the size of the capacitance film vacuum gauge is designed to be 10mm multiplied by 10mm, the capacitance film vacuum gauge comprises an upper substrate 7, a lower substrate 8 and a silicon chip 1, a pressure sensing film 10 is etched on the silicon chip 1 by adopting a concentrated boron doping technology, the upper substrate 7 and the lower substrate 8 are made of Pyrex glass, the silicon chip 1, the upper substrate and the lower substrate are subjected to monocrystalline silicon-glass bonding, a single-side capacitance structure is adopted, the concentrated boron doping pressure sensing film 10 and an electrode plated on the lower substrate form a flat capacitor. The extraction electrode 3 of the lower substrate electrode 2 and the electrode lead 11 of the pressure-sensitive film 10 are both extracted from the upper substrate, a vent 9 is provided in the middle of the upper substrate at a position aligned with the pressure-sensitive film, and the air inlet is sealed by a glass sealing tube 4 in order to protect the pressure-sensitive film from being damaged in the atmospheric environment.
During testing, the sensor is placed in a vacuum environment to be tested, the glass sealing tube 4 is broken, and the capacitance value between the lower substrate electrode 2 and the electrode of the pressure sensing film is measured to obtain the vacuum degree of the vacuum environment to be tested.
The silicon wafer 1 of the present invention, as shown in fig. 2, comprises a pressure-sensitive film structure and a support structure, and has a size of 10mm × 10mm × 56 μm, wherein the pressure-sensitive film is heavily boron-doped P + + Si, and has a size of 5mm × 5mm × 16 μm, and the depth of the upper and lower cavities is 20 μm. The pressure-sensing film electrode lead is realized on monocrystalline silicon by adopting a concentrated boron doping technology. Meanwhile, the silicon chip 1 is provided with an electrode lead-out hole A5 for leading out a lower substrate electrode 2.
The lower substrate of the present invention, as shown in fig. 3, includes two parts, i.e., a lower substrate and a lower substrate electrode 2, each having a size of 10mm × 10mm × 5mm, wherein the lower substrate is made of Pyrex glass, and the lower substrate electrode 2 is Ti + Au and has a thickness of 300 nm.
As shown in fig. 4, the upper substrate of the present invention is made of Pyrex glass and has dimensions of 10mm × 10mm × 5mm, and the upper substrate is provided with electrode lead-out holes B6 and vent holes 9.
In order to obtain optimized design parameters of the pressure-sensitive film, the side length and the thickness of the film are subjected to combined analysis by adopting an orthogonal optimization method, and key parameters concerned by the invention comprise: maximum deflection 1000Pa, base capacitance, sensitivity, and maximum stress.
In addition, the process difficulty and the product robustness are also key factors that must be considered in the design process. Simulation test results show that: for films with various side lengths, the maximum deflection, the sensitivity and the maximum stress of the film are all reduced along with the increase of the thickness, and the basic capacitance shows an opposite change rule because the basic capacitance is inversely proportional to the maximum deflection. Increasing the film thickness can reduce the process difficulty and improve the reliability of the sensor, but at the same time, the sensitivity is reduced; to improve sensitivity, the side length of the film can be increased, but this increases the process difficulty. Therefore, the size of the film must be reasonably optimized. When the side length is smaller, such as 2mm, the sensitivity is too low to be less than or equal to 0.2 fF/Pa; when the side length is increased to 6mm, a very high sensitivity of 2fF/Pa can be obtained even at a larger thickness of 20 μm. Therefore, the side length of the film should be as large as possible, as the process conditions allow. In view of the above, the film side length was designed to be 5mm and the thickness was designed to be 16 μm. Under the design parameters, the maximum deflection of the film under the pressure of 1000Pa is 14 μm, the maximum stress is 2.70E +07Pa, and the minimum sensitivity is 2.2 fF/Pa.
In summary, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (3)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911362566.8A CN111141443A (en) | 2019-12-26 | 2019-12-26 | A Capacitive Thin Film Vacuum Gauge Based on MEMS Technology |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911362566.8A CN111141443A (en) | 2019-12-26 | 2019-12-26 | A Capacitive Thin Film Vacuum Gauge Based on MEMS Technology |
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| CN111141443A true CN111141443A (en) | 2020-05-12 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111982383A (en) * | 2020-07-06 | 2020-11-24 | 厦门大学 | Differential pressure contact type MEMS capacitance film vacuum gauge |
Citations (7)
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|---|---|---|---|---|
| CN1379228A (en) * | 2002-05-13 | 2002-11-13 | 厦门大学 | Pressure sensor with electrostatic bonding and sealed capacitor cavity and its preparing process |
| CN2738224Y (en) * | 2004-09-27 | 2005-11-02 | 厦门大学 | Capacitance pressure sensor for vacuum measurement |
| CN102169038A (en) * | 2011-01-10 | 2011-08-31 | 中国电子科技集团公司第五十五研究所 | Side wall protection method for MEMS (Micro Electronic Mechanical System) silicon capacitive pressure transducer with sandwich structure |
| CN102445298A (en) * | 2011-11-25 | 2012-05-09 | 沈阳仪表科学研究院 | Method for improving overloading response speed of silicon capacitive pressure sensor |
| CN203365045U (en) * | 2013-07-16 | 2013-12-25 | 东南大学 | Capacitive air pressure sensor of microelectronic mechanical system |
| CN107356367A (en) * | 2017-07-20 | 2017-11-17 | 中国电子科技集团公司第四十九研究所 | One kind miniaturization differential type double-capacitance film vacuum sensor |
| CN108700479A (en) * | 2016-02-25 | 2018-10-23 | 英福康股份公司 | Capacitive vacuum measuring cell with multiple electrodes |
-
2019
- 2019-12-26 CN CN201911362566.8A patent/CN111141443A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1379228A (en) * | 2002-05-13 | 2002-11-13 | 厦门大学 | Pressure sensor with electrostatic bonding and sealed capacitor cavity and its preparing process |
| CN2738224Y (en) * | 2004-09-27 | 2005-11-02 | 厦门大学 | Capacitance pressure sensor for vacuum measurement |
| CN102169038A (en) * | 2011-01-10 | 2011-08-31 | 中国电子科技集团公司第五十五研究所 | Side wall protection method for MEMS (Micro Electronic Mechanical System) silicon capacitive pressure transducer with sandwich structure |
| CN102445298A (en) * | 2011-11-25 | 2012-05-09 | 沈阳仪表科学研究院 | Method for improving overloading response speed of silicon capacitive pressure sensor |
| CN203365045U (en) * | 2013-07-16 | 2013-12-25 | 东南大学 | Capacitive air pressure sensor of microelectronic mechanical system |
| CN108700479A (en) * | 2016-02-25 | 2018-10-23 | 英福康股份公司 | Capacitive vacuum measuring cell with multiple electrodes |
| CN107356367A (en) * | 2017-07-20 | 2017-11-17 | 中国电子科技集团公司第四十九研究所 | One kind miniaturization differential type double-capacitance film vacuum sensor |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111982383A (en) * | 2020-07-06 | 2020-11-24 | 厦门大学 | Differential pressure contact type MEMS capacitance film vacuum gauge |
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