CN113513605B - MEMS mass flow controller based on electromagnetic control valve and control method - Google Patents
MEMS mass flow controller based on electromagnetic control valve and control method Download PDFInfo
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K7/00—Diaphragm valves or cut-off apparatus, e.g. with a member deformed, but not moved bodily, to close the passage ; Pinch valves
- F16K7/12—Diaphragm valves or cut-off apparatus, e.g. with a member deformed, but not moved bodily, to close the passage ; Pinch valves with flat, dished, or bowl-shaped diaphragm
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K31/00—Actuating devices; Operating means; Releasing devices
- F16K31/02—Actuating devices; Operating means; Releasing devices electric; magnetic
- F16K31/06—Actuating devices; Operating means; Releasing devices electric; magnetic using a magnet, e.g. diaphragm valves, cutting off by means of a liquid
- F16K31/0644—One-way valve
- F16K31/0672—One-way valve the valve member being a diaphragm
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K31/00—Actuating devices; Operating means; Releasing devices
- F16K31/02—Actuating devices; Operating means; Releasing devices electric; magnetic
- F16K31/06—Actuating devices; Operating means; Releasing devices electric; magnetic using a magnet, e.g. diaphragm valves, cutting off by means of a liquid
- F16K31/0675—Electromagnet aspects, e.g. electric supply therefor
Abstract
The invention discloses an MEMS mass flow controller based on an electromagnetic control valve and a control method thereof, wherein the MEMS mass flow controller comprises a shell, a mass flow sensor and a diaphragm, wherein the shell comprises a lower substrate, an upper cover plate and an airflow channel enclosed by the lower substrate and the upper cover plate; the mass flow sensor is arranged on one side, close to the inlet of the airflow channel, of the lower substrate; the diaphragm is arranged on one side of the lower substrate close to the outlet of the airflow channel; two ends of the diaphragm are arranged on the lower substrate, and a vibration gap is arranged between the middle part of the diaphragm and the lower substrate; the lower surface of the diaphragm is provided with a magnetic part, and the position of the upper cover plate or the lower base plate corresponding to the magnetic part is provided with an electromagnetic coil. The mass flow sensor is used for accurately measuring and feeding back the gas flow in real time to serve as a basis for adjusting the power-on state of the electromagnetic coil, and then the magnetic force is used for driving the diaphragm to deform, so that the size of the gas flow channel is changed, and the high-precision control of the micro flow is realized.
Description
Technical Field
The invention relates to the technical field of flow measurement and control, in particular to an MEMS mass flow controller based on an electromagnetic control valve and a control method.
Background
Flow measurement and control are essential requirements for industrial production and scientific research. The mass flow controller is a device capable of directly measuring and controlling the mass flow of gas, and plays an important role in various fields of semiconductors, integrated circuits, petrochemical industry, vacuum coating, medicines, environmental protection and the like. The core components of a mass flow controller include a mass flow sensor and an electromagnetic regulating valve. The sensor can realize accurate measurement of gas mass flow, and the electromagnetic regulating valve can regulate and control the flow according to the measurement result.
At present, in a domestic mass flow controller, a sensor generally utilizes the principle of a capillary heat transfer temperature difference calorimetry, a group of thermistor wires are respectively manufactured at the upstream and the downstream of a capillary, and two precision resistors are externally connected to form an electric bridge structure. When the gas flow sensor works, the electric bridge is heated, if airflow passes through the electric bridge, the temperature of the thermistor wires at the upstream and downstream is different, and the electric bridge outputs a voltage signal which is proportional to the mass flow of the gas. Solenoid valves are typically assembled from a number of precision machined components. The controller has complex manufacturing process, high price and poor precision when controlling the micro flow; in addition, the problems of zero drift and particulate pollution exist after long-term use, and the maintenance cost is high.
With the rapid development of the MEMS technology, the sensor and the actuator manufactured by the technology are concerned with due to the advantages of simple structure, small volume, low cost, high precision, etc. Therefore, it is of great significance to develop a MEMS mass flow controller.
Disclosure of Invention
In order to solve the technical problems, the invention provides an MEMS mass flow controller based on an electromagnetic control valve and a control method, which have the characteristics of simple structure, small volume, low cost and strong preparation controllability and are suitable for high-precision control of micro flow.
In order to achieve the purpose, the technical scheme of the invention is as follows:
an MEMS mass flow controller based on an electromagnetic control valve comprises a shell, a mass flow sensor and a diaphragm, wherein the mass flow sensor and the diaphragm are positioned in the shell; the mass flow sensor is arranged on one side, close to the inlet of the airflow channel, of the lower substrate; the membrane is arranged on one side, close to the outlet of the airflow channel, of the lower substrate; two ends of the diaphragm are arranged on the lower substrate, and a vibration gap is arranged between the middle part of the diaphragm and the lower substrate; the lower surface of the diaphragm is provided with a magnetic part, an electromagnetic coil is arranged at a position, corresponding to the magnetic part, on the upper cover plate or the lower base plate, the polarization directions of the magnetic poles, facing to each other, of the electromagnetic coil on the upper cover plate are opposite to the polarization directions of the magnetic poles, facing to each other, of the magnetic parts, of the electromagnetic coil on the lower base plate are the same as the polarization directions of the magnetic poles, facing to each other, of the magnetic parts;
the mass flow sensor is manufactured by adopting an MEMS process and is fixed on the lower substrate by a bonding method, and the mass flow sensor comprises:
the substrate is provided with a heat insulation cavity which is communicated along the vertical direction;
the supporting layer is formed on the substrate and the heat insulation cavity;
the heating element is formed on the upper surface of the supporting layer and is locally positioned above the heat insulation cavity;
the temperature sensing elements are formed on the upper surface of the supporting layer, are symmetrically distributed on two sides of the heating element and are locally positioned above the heat insulation cavity;
the metal layer is formed on the upper surface of the supporting layer;
the insulating layer covers the heating element, the temperature sensing element and the metal layer, and a contact hole exposing part of the metal layer is formed on the insulating layer through local etching.
In the above scheme, the position of the diaphragm is lower than that of the mass flow sensor, and a downward bulge is arranged at the position, corresponding to the diaphragm, on the inner side of the upper cover plate.
In the scheme, the diaphragm has ductility and is fixed on the lower substrate by a bonding or mechanical clamping method; the electromagnetic coil is formed by etching a metal material or a semiconductor material and is in a circular spiral structure or a polygonal spiral structure; the magnetic part is a permanent magnet.
In a further technical scheme, the substrate comprises one of a silicon substrate, a germanium substrate, an SOI substrate and a GeOI substrate.
In a further technical scheme, the supporting layer and the insulating layer are made of one or a combination of silicon oxide and silicon nitride.
In a further technical scheme, the heating element is made of one of P-type polycrystalline silicon, N-type polycrystalline silicon and metal.
In a further technical scheme, the temperature sensing element is a thermistor or a thermopile; the material of the thermistor is metal with a positive/negative temperature coefficient, and the material of the thermopile is a combination of P-type polycrystalline silicon/N-type polycrystalline silicon, or a combination of P-type polycrystalline silicon/metal, or a combination of N-type polycrystalline silicon/metal.
In a further technical scheme, the metal layer is made of one or a combination of more of metal titanium, tungsten, chromium, platinum, aluminum and gold.
A MEMS mass flow control method based on an electromagnetic control valve is adopted, gas is introduced into a shell from an inlet of an airflow channel and is discharged from an outlet through the airflow channel, the mass flow of the gas is measured by a mass flow sensor during the process, the mass flow is fed back to a rear-end processing circuit to be compared with a given value, then the power-on state of an electromagnetic coil is dynamically adjusted by utilizing the feedback, the deformation degree of a diaphragm is controlled, namely the size of the airflow channel is controlled, and therefore the accurate control of the gas mass flow is realized.
Through the technical scheme, the MEMS mass flow controller based on the electromagnetic control valve and the control method have the following beneficial effects:
the MEMS mass flow controller based on the electromagnetic control valve is manufactured by adopting an MEMS process, has the characteristics of simple structure, small volume and low cost, avoids a complex preparation process, and has strong controllability; the invention utilizes the MEMS mass flow sensor to accurately measure the gas flow, takes the measured voltage as the feedback quantity to guide and adjust the electrifying state of the electromagnetic coil, further utilizes the magnetic force to drive the diaphragm to deform, and changes the size of the gas flow channel, thereby realizing the accurate control of the micro flow.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below.
Fig. 1 is a schematic structural diagram (initial state) of a MEMS mass flow controller based on a solenoid control valve according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram (working state) of a MEMS mass flow controller based on a solenoid control valve according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram (initial state) of a MEMS mass flow controller based on an electromagnetic control valve according to a second embodiment of the present invention;
fig. 4 is a schematic structural diagram (working state) of a MEMS mass flow controller based on an electromagnetic control valve according to a second embodiment of the present invention;
fig. 5 is a schematic structural diagram (initial state) of a MEMS mass flow controller based on a solenoid control valve according to a third embodiment of the present invention;
fig. 6 is a schematic structural diagram (working state) of a MEMS mass flow controller based on a solenoid control valve according to a third embodiment of the present invention;
fig. 7 is a schematic structural diagram (initial state) of a MEMS mass flow controller based on a solenoid control valve according to a fourth embodiment of the present invention;
fig. 8 is a schematic structural diagram (working state) of a MEMS mass flow controller based on a solenoid control valve according to a fourth embodiment of the present invention;
FIG. 9 is a schematic cross-sectional view of a mass flow sensor employed in an embodiment of the present invention;
in the figure, 1, a housing; 101. a lower substrate; 102. an upper cover plate; 103. an air flow channel; 104. an inlet; 105. an outlet; 106. a protrusion; 107. a vibration gap; 2. a mass flow sensor; 3. a membrane; 4. an electromagnetic coil; 5. a magnetic member; 201. a substrate; 202. a support layer; 203. a heating element; 204. a temperature sensing element; 205. a metal layer; 206. an insulating layer; 207. a contact hole; 208. a thermally insulated cavity.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.
The invention provides an MEMS mass flow controller based on an electromagnetic control valve, which comprises the following specific embodiments:
example one
Referring to fig. 1 and 2, an MEMS mass flow controller based on an electromagnetic control valve includes a housing 1, a mass flow sensor 2, a diaphragm 3, an electromagnetic coil 4, and a magnetic member 5; the housing 1 comprises a lower substrate 101, an upper cover plate 102 and an airflow channel 103 enclosed by the two; the mass flow rate sensor 2 is disposed on the opposite left side of the lower substrate 101, i.e., on the side close to the inlet 104 of the gas flow channel 103; the diaphragm 3 is arranged on the opposite right side of the lower substrate 101, namely, the side close to the outlet 105 of the airflow channel 103, the position of the diaphragm 3 is lower than that of the mass flow sensor 2, the inner side of the upper cover plate 102 is provided with a downward bulge 106 corresponding to the position of the diaphragm 3, two ends of the diaphragm 3 are arranged on the lower substrate 101, and a vibration gap 107 is arranged between the middle part of the diaphragm 3 and the lower substrate 101. The air flow channel 103 is in a broken line shape, and air flow can be buffered to a certain extent. The electromagnetic coil 4 and the magnetic member 5 are respectively disposed on the lower surface of the protrusion 106 of the upper cover plate 102 and the lower surface of the diaphragm 3, and the polarization directions of the magnetic poles of the electromagnetic coil 4 and the magnetic member 5 facing each other are opposite.
Example two
Referring to fig. 3 and 4, an MEMS mass flow controller based on an electromagnetic control valve includes a housing 1, a mass flow sensor 2, a diaphragm 3, an electromagnetic coil 4, and a magnetic member 5; the housing 1 comprises a lower substrate 101, an upper cover plate 102 and an airflow channel 103 enclosed by the two; the mass flow rate sensor 2 is disposed on the opposite left side of the lower substrate 101, i.e., on the side close to the inlet 104 of the gas flow passage 103; the membrane 3 is disposed on the opposite right side of the lower substrate 101, i.e., the side near the outlet 105 of the airflow channel 103, both ends of the membrane 3 are disposed on the lower substrate 101, and a vibration gap 107 is disposed between the middle of the membrane 3 and the lower substrate 101. The mass flow sensor 2 and the upper surface of the diaphragm 3 are located at the same level, and the airflow passage 103 is in the shape of a horizontal straight line. The electromagnetic coil 4 and the magnetic member 5 are respectively disposed on the lower surface of the upper cover plate 102 and the lower surface of the diaphragm 3, and the polarization directions of the magnetic poles of the electromagnetic coil 4 and the magnetic member 5 facing each other are opposite.
EXAMPLE III
Referring to fig. 5 and 6, an MEMS mass flow controller based on an electromagnetic control valve includes a housing 1, a mass flow sensor 2, a diaphragm 3, an electromagnetic coil 4, and a magnetic member 5; the housing 1 comprises a lower substrate 101, an upper cover plate 102 and an airflow channel 103 enclosed by the two; the mass flow rate sensor 2 is disposed on the opposite left side of the lower substrate 101, i.e., on the side close to the inlet 104 of the gas flow passage 103; the diaphragm 3 is arranged on the opposite right side of the lower substrate 101, namely, the side close to the outlet 105 of the airflow channel 103, the position of the diaphragm 3 is lower than that of the mass flow sensor 2, the inner side of the upper cover plate 102 is provided with a downward bulge 106 corresponding to the position of the diaphragm 3, two ends of the diaphragm 3 are arranged on the lower substrate 101, and a vibration gap 107 is arranged between the middle part of the diaphragm 3 and the lower substrate 101. The air flow channel 103 is in a zigzag shape, and air flow can be buffered to a certain extent. The electromagnetic coil 4 and the magnetic member 5 are respectively disposed on the upper surface of the lower substrate 101 and the lower surface of the diaphragm 3, and the polarization directions of the magnetic poles of the electromagnetic coil 4 and the magnetic member 5 facing each other are the same.
Example four
Referring to fig. 7 and 8, an MEMS mass flow controller based on an electromagnetic control valve includes a housing 1, a mass flow sensor 2, a diaphragm 3, an electromagnetic coil 4, and a magnetic member 5; the housing 1 comprises a lower substrate 101, an upper cover plate 102 and an airflow channel 103 enclosed by the two; the mass flow rate sensor 2 is disposed on the opposite left side of the lower substrate 101, i.e., on the side close to the inlet 104 of the gas flow channel 103; the membrane 3 is disposed on the opposite right side of the lower substrate 101, i.e. the side close to the outlet 105 of the airflow channel 103, two ends of the membrane 3 are disposed on the lower substrate 101, and a vibration gap 107 is disposed between the middle of the membrane 3 and the lower substrate 101. The mass flow sensor 2 and the upper surface of the diaphragm 3 are located at the same level, and the airflow passage 103 is in the shape of a horizontal straight line. The electromagnetic coil 4 and the magnetic member 5 are respectively disposed on the upper surface of the lower substrate 101 and the lower surface of the diaphragm 3, and the polarization directions of the magnetic poles of the electromagnetic coil 4 and the magnetic member 5 facing each other are the same.
Specifically, the housing 1 is made of a rigid material that is airtight, the lower substrate 101 and the upper cover plate 102 are fixedly connected by welding, crimping, fastening, snapping and the like, and the cross-sectional shape of the airflow channel 103 is circular or polygonal; in the embodiment of the present invention, the material of the housing 1 is an aluminum alloy, the lower substrate 101 and the upper cover plate 102 are fixed by fastening, and the cross-sectional shape of the air flow channel 103 is rectangular.
Specifically, the mass flow sensor 2 is manufactured by an MEMS process, and is fixed on the lower substrate 101 by an adhesive method. Referring to fig. 9, in an embodiment of the present invention, the mass flow sensor 2 includes:
a substrate 201 provided with a heat insulating cavity 208 which is penetrated in the vertical direction;
a support layer 202 formed on the substrate 201 and the insulating cavity 208;
a heating element 203 formed on the upper surface of the support layer 202 and partially located above the insulating cavity 208;
the temperature sensing elements 204 are formed on the upper surface of the supporting layer 202, and the two temperature sensing elements 204 are symmetrically distributed on two sides of the heating element 203 and are locally positioned above the heat insulation cavity 208;
a metal layer 205 formed on the upper surface of the support layer 208;
an insulating layer 206 covering the heating element 203, the temperature sensing element 204 and the metal layer 205, and a contact hole 207 exposing a portion of the metal layer 205 is formed on the insulating layer 206 by partial etching.
The substrate 201 is a common semiconductor substrate including, but not limited to, one of a silicon substrate, a germanium substrate, an SOI substrate, a GeOI substrate; in an embodiment of the present invention, substrate 201 is a double-side polished single crystal silicon substrate.
The cross-sectional shape of the insulating cavity 208 includes, but is not limited to, one of rectangular, trapezoidal, and inverted trapezoidal; in an embodiment of the present invention, the cross-sectional shape of the insulating cavity 208 is rectangular.
The materials of the support layer 202 and the insulating layer 206 are one or two of silicon oxide and silicon nitride; in the embodiment of the present invention, the support layer 202 is made of silicon oxide and silicon nitride, and the material of the insulating layer 206 is silicon oxide.
The material of the heating element 203 is one of P-type polysilicon, N-type polysilicon and metal; in an embodiment of the present invention, the material of the heating element 203 is platinum.
The temperature sensing element 204 can be a thermistor or a thermopile; the material of the thermistor is metal with positive/negative temperature coefficients, and the material of the thermopile is a combination of P-type polycrystalline silicon/N-type polycrystalline silicon, or a combination of P-type polycrystalline silicon/metal, or a combination of N-type polycrystalline silicon/metal; in the embodiment of the present invention, the temperature sensing element 32 is a P-type polysilicon/N-type polysilicon thermopile, in which P-type polysilicon and N-type polysilicon are connected by a portion of the metal layer 205.
The metal layer 205 is made of one or more of titanium, tungsten, chromium, platinum, aluminum and gold; in an embodiment of the present invention, the material of the metal layer 205 is chromium/gold.
It should be noted that the working principle of the mass flow sensor 2 is as follows: the heating element 203 provides a certain power to make the surface temperature of the sensor higher than the ambient temperature, when no gas flows, the surface temperature is normally distributed by taking the heating element 203 as the center, and the temperature sensing elements 204 on the two sides have the same electric signal; when gas flows, the temperature distribution on the sensor surface is shifted by the heat transferred by the gas molecules, and the electric signals of the temperature sensing elements 204 on the two sides are different, so that the gas flow can be calculated by utilizing the difference.
The diaphragm 3 is made of a material with good ductility as long as the diaphragm is convenient to deform under the action of magnetic force; the membrane 3 may be fixed to the lower substrate 101 by means of bonding or mechanical clamping.
The electromagnetic coil 4 is formed by etching a metal material or a semiconductor material, and the shape of the electromagnetic coil can be a circular spiral structure or a polygonal spiral structure as long as the electromagnetic coil is convenient to generate a magnetic field after being electrified.
The magnetic member 5 may be a permanent magnet, specifically, a magnetic thin film material, as long as it can retain a high remanence for a long time.
The membrane 3 is the movable part of the MEMS mass flow controller based on the solenoid control valve of the present invention: in the first and second embodiments, after the electromagnetic coil 4 is energized, because the magnetic poles facing each other with the magnetic member 5 are polarized in opposite directions, an attractive force is generated between the two, and the driving diaphragm is deformed upward, so that the airflow passage 103 is reduced. In the third and fourth embodiments, after the electromagnetic coil 4 is energized, since the magnetic poles facing each other with the magnetic member 5 have the same polarization direction, a repulsive force is generated between the two, and the driving diaphragm is deformed upward, so that the airflow passage 103 is reduced.
The different electrified states, the different degree that the diaphragm takes place the deformation, and the size that airflow channel 103 is also different. Therefore, the operating principle of the MEMS mass flow controller based on the electromagnetic control valve is as follows: after gas is introduced into the housing 1 from the inlet 104 of the gas flow channel 103, the gas is discharged from the outlet 105 through the gas flow channel 103, the mass flow of the gas is measured by the mass flow sensor 2 during the period, and is fed back to a rear-end processing circuit to be compared with a given value, and then the power-on state of the electromagnetic coil 4 is dynamically adjusted by utilizing the feedback, so that the deformation degree of the diaphragm 3 is controlled, namely the size of the gas flow channel 103 is controlled, and the accurate control of the gas mass flow is realized.
In conclusion, the MEMS mass flow controller based on the electromagnetic control valve is manufactured by adopting the MEMS process, has the characteristics of simple structure, small volume and low cost, avoids the complex preparation process and has strong controllability; the invention utilizes the MEMS mass flow sensor to accurately measure the gas flow, takes the measured voltage as a feedback quantity to guide and adjust the power-on state of the electromagnetic coil, further utilizes the magnetic force to drive the diaphragm to deform, and changes the size of the gas flow channel, thereby realizing the accurate control of the micro flow.
Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (9)
1. An MEMS mass flow controller based on an electromagnetic control valve is characterized by comprising a shell, a mass flow sensor and a diaphragm, wherein the mass flow sensor and the diaphragm are positioned in the shell; the mass flow sensor is arranged on one side, close to the inlet of the airflow channel, of the lower substrate; the membrane is arranged on one side, close to the outlet of the airflow channel, of the lower substrate; two ends of the diaphragm are arranged on the lower substrate, and a vibration gap is arranged between the middle part of the diaphragm and the lower substrate; the lower surface of the diaphragm is provided with a magnetic part, an electromagnetic coil is arranged at a position, corresponding to the magnetic part, on the upper cover plate or the lower base plate, the polarization directions of the magnetic poles, facing to each other, of the electromagnetic coil on the upper cover plate are opposite to the polarization directions of the magnetic poles, facing to each other, of the magnetic parts, of the electromagnetic coil on the lower base plate are the same as the polarization directions of the magnetic poles, facing to each other, of the magnetic parts;
the mass flow sensor is manufactured by adopting an MEMS process and is fixed on the lower substrate by a bonding method, and the mass flow sensor comprises:
the substrate is provided with a heat insulation cavity which is communicated along the vertical direction;
the supporting layer is formed on the substrate and the heat insulation cavity;
the heating element is formed on the upper surface of the supporting layer and is locally positioned above the heat insulation cavity;
the temperature sensing elements are formed on the upper surface of the supporting layer, are symmetrically distributed on two sides of the heating element and are locally positioned above the heat insulation cavity;
the metal layer is formed on the upper surface of the supporting layer;
the insulating layer covers the heating element, the temperature sensing element and the metal layer, and a contact hole exposing part of the metal layer is formed on the insulating layer through local etching.
2. A MEMS valve-based mass flow controller according to claim 1, wherein the diaphragm is located lower than the mass flow sensor, and the inner side of the upper cover plate is provided with a downward projection corresponding to the location of the diaphragm.
3. The MEMS valve-based mass flow controller of claim 1, wherein the membrane is malleable and is affixed to the lower substrate by bonding or mechanical clamping; the electromagnetic coil is formed by etching a metal material or a semiconductor material and is in a circular spiral structure or a polygonal spiral structure; the magnetic part is a permanent magnet.
4. The solenoid control valve based MEMS mass flow controller of claim 1 wherein the substrate is one of a silicon substrate, a germanium substrate, an SOI substrate, a GeOI substrate.
5. The solenoid control valve based MEMS mass flow controller of claim 1, wherein the material of the supporting layer and the insulating layer is one or two combination of silicon oxide and silicon nitride.
6. A solenoid control valve based MEMS mass flow controller according to claim 1 wherein the material of said heating element is one of P-type polysilicon, N-type polysilicon, metal.
7. A solenoid control valve based MEMS mass flow controller according to claim 1 wherein the temperature sensing element is a thermistor or a thermopile; the material of the thermistor is metal with positive/negative temperature coefficients, and the material of the thermopile is a combination of P-type polycrystalline silicon/N-type polycrystalline silicon, or a combination of P-type polycrystalline silicon/metal, or a combination of N-type polycrystalline silicon/metal.
8. The solenoid control valve based MEMS mass flow controller of claim 1, wherein the material of the metal layer is one or more combinations of metals titanium, tungsten, chromium, platinum, aluminum, gold.
9. An MEMS mass flow control method based on an electromagnetic control valve, which adopts the MEMS mass flow controller based on the electromagnetic control valve as claimed in claim 1, and is characterized in that after gas is introduced into the shell from the inlet of the gas flow channel and is discharged from the outlet through the gas flow channel, the mass flow of the gas is measured by the mass flow sensor during the process, and the mass flow is fed back to a rear-end processing circuit to be compared with a given value, and then the feedback is utilized to dynamically adjust the power-on state of the electromagnetic coil, so as to control the deformation degree of the diaphragm, namely the size of the gas flow channel, and further realize the accurate control of the gas mass flow.
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Application publication date: 20211019 Assignee: Suzhou Taichu Microelectronics Technology Co.,Ltd. Assignor: Qingdao Xinsheng micro nano electronic technology Co.,Ltd. Contract record no.: X2023980044029 Denomination of invention: A MEMS Mass Flow Controller and Control Method Based on Electromagnetic Control Valve Granted publication date: 20230324 License type: Common License Record date: 20231020 |