Electrode of calorimetric micro-flow sensor and preparation method thereof

Abstract

The invention discloses an electrode of a calorimetric micro-flow sensor and a preparation method of the electrode, the electrode is configured to be of an arch structure, and the distance between the lowest position of the arch structure and an electrode mounting plate is 200 microns. According to the electrode of the calorimetric micro-flow sensor and the preparation method of the electrode, the arch electrode is provided, due to the fact that the distance is formed between the electrode and the substrate, the consumption of the electrode heating temperature conducted on the substrate is small, and after the heating electrode generates the similar temperature, the same gas flow rate is introduced; the maximum temperature difference of the temperature measuring electrodes on the two sides is 6 DEG C and 55 DEG C respectively, the temperature difference is increased by 49 DEG C, the measurement precision is better, and the electrode of the structure can have obvious temperature difference discrimination at different air temperatures and heating electrode temperatures and at different flow speeds and the optimal distance between the temperature measuring electrodes on the two sides and the heating electrode in the center, so that the measurement accuracy is improved. And the resolution and the sensitivity of the sensor are improved.

Description

Technical Field

[0001] The present invention relates to the field of sensor design, and more specifically, to an electrode of a calorimetric micro-flow sensor and a preparation method thereof. Background Art

[0002] Micro flow sensors, usually MEMS (micro-electromechanical systems) devices, are devices used to measure tiny flows (such as airflow or trace liquid flow). According to their working principles, micro flow sensors can be divided into many types, such as thermal micro flow sensors, piezoelectric micro flow sensors, etc. Among them, thermal micro flow sensors detect flow velocity based on the heat transfer principle of fluid. When the fluid passes through a stable thermal field heated by a heat source at a certain speed, the thermal field will change. By measuring this change, accurate measurement of flow velocity can be achieved. Among them, thermal flow sensors can be divided into hot wire flow sensors and calorimetric flow sensors. Compared with hot wire flow sensors, calorimetric flow sensors have smaller size, larger range, higher integration, and are less affected by the environment and conditions, so they are particularly widely used. However, the current method for preparing calorimetric micro sensors mainly uses photolithography to prepare sensor chips and integrate channels, signal processing circuits and sensor chips together. However, the photolithography preparation method is costly, and its process is complex and requires high operation.

[0003] At the same time, the heating electrodes on the existing calorimetric flow sensors all adopt a fitted design, so traditional flow sensors will make a hollow structure to improve sensor performance. However, due to the fitted design with the substrate, the temperature generated by the heating electrode will diffuse from the surface of the substrate, affecting its detection sensitivity and increasing its power consumption. Summary of the invention

[0004] An object of the present invention is to solve at least the above problems and / or disadvantages and to provide at least the advantages which will be described hereinafter.

[0005] To achieve these objectives and other advantages of the present invention, an electrode of a calorimetric micro-flow sensor is provided. The electrode is configured to have an arch structure, and a distance of 200 μm is provided between the lowest point of the arch structure and an electrode mounting plate.

[0006] Preferably, the electrode is configured to include:

[0007] Two metal pillars are arranged opposite to each other on the electrode mounting plate;

[0008] A comb-type electrode disposed at the upper end of each metal column and used to connect two metal columns into an integrated structure;

[0009] Wherein, the height of the metal column is 200 μm and the diameter is 50 μm.

[0010] Preferably, the overall size of the comb electrode is 650 μm×300 μm, and the electrode wire in the comb electrode has a width of 50 μm and a height of 20 μm.

[0011] A method for preparing an arch electrode, which is used in the preparation of an electrode of a calorimetric micro-flow sensor, comprises:

[0012] S1. preparing a conductive substrate;

[0013] S2, connecting the substrate to the negative electrode, and depositing metal pillars on the metal film by MCED electrochemical deposition method;

[0014] S3. Depositing a comb-type electrode structure laterally above the metal pillar.

[0015] Preferably, in S1, the preparation method of the conductive substrate comprises:

[0016] S10, pre-treating the base material to remove grease, dust and other impurities on the surface of the base material;

[0017] S11. Place the base material in a vacuum chamber of a predetermined cleanliness level, and heat the selected metal material so that the metal atoms or ions that are evaporated or sputtered into gaseous form can be adsorbed and condensed on the surface of the silicon wafer, thereby obtaining a metal film layer on the base material through physical vapor deposition.

[0018] Preferably, it is characterized in that, in S2, the method of depositing the metal pillar comprises:

[0019] S20, adding an electrolyte solution for preparing deposited metal into a pipette, and inserting a metal wire into the pipette and connecting the metal wire to the positive electrode;

[0020] S21. When the electrolyte solution in the pipette contacts the conductive substrate, the metal ions in the electrolyte solution are reduced to metal by electrons and deposited on the substrate, while the metal in the pipette loses electrons and is oxidized to metal ions, thereby replenishing the metal ions lost in the pipette;

[0021] S22. Adjust the height of the pipette to deposit the metal column until the metal column reaches a predetermined height.

[0022] Preferably, in S3, during the process of lateral deposition of the comb-type electrode structure, the position of the deposition pipette is controlled by a multi-degree-of-freedom displacement component, and the multi-degree-of-freedom displacement component is communicatively connected to an external control terminal.

[0023] Preferably, the method further comprises simulating the performance of the arch electrode by simulation, wherein the simulation process comprises:

[0024] S4. Modeling the structures of the fitted electrode and the arch electrode respectively by using modeling software;

[0025] S5, importing each electrode model after modeling into COMSOL finite element simulation software, and setting each substrate material to silicon wafer and each electrode material to metal, thus completing the establishment of the simulation model;

[0026] S6. Free air with a height of 0.5 mm is set above each simulation model, and air with different flow rates is introduced on one side. Different thermal powers are set for the middle heating electrodes of the sensors corresponding to the fitted electrodes and the arch electrodes to achieve the same temperature of the heating electrodes, and the heating powers are compared to complete the simulation analysis after the meshing of the models.

[0027] S7. Through simulation analysis, the optimal distance between the temperature measuring electrodes on both sides and the central heating electrode at different flow rates is obtained.

[0028] Preferably, at an air temperature of 0 to 50° C. and an air velocity of 0 to 1 m / s, the distance between the temperature measuring electrodes on both sides and the central heating electrode is 200 to 250 μm.

[0029] Preferably, by simulating different air temperatures of 0°C, 25°C, and 50°C and different heating electrode temperatures of 100°C and 150°C, and passing air flow rates of 0.1m / s, 0.4m / s, 0.7m / s, and 1.0m / s, it is obtained that the distance between the temperature measuring electrodes on both sides and the central heating electrode is preferably 238μm.

[0030] The present invention includes at least the following beneficial effects: First, the present invention provides an arch electrode. Due to the spacing between the electrode and the substrate, the conduction consumption of the electrode heating temperature in the substrate is reduced. After the heating electrodes produce similar temperatures, the same gas flow rate is introduced, and the maximum temperature difference of the temperature measuring electrodes on both sides is 6°C and 55°C respectively, which improves the temperature difference by 49°C, making its measurement accuracy better.

[0031] Secondly, through simulation experiments, it can be known that the arch electrode of the present invention, under the influence of the ambient temperature of 0-50 air temperature and the heating electrode temperature of 100°C and 150°C, when the temperature measuring electrodes on both sides are about 238μm away from the central heating electrode, can have a stable temperature difference with obvious temperature difference differentiation, so that the measurement resolution and sensitivity are better.

[0032] Thirdly, through simulation experiments, it can be known that the arch electrode of the present invention has a small contact area between the heating electrode and the substrate, so that the generated temperature will not diffuse in the substrate and cause temperature loss, and the contact area between the electrode and the gas is increased. Therefore, compared with traditional electrodes, the thermal power consumed to achieve the same temperature is quite different. That is, if the temperature needs to reach 150°C, the traditional sensor needs to set a thermal power of 0.175W, while the new sensor of the present invention only needs to set a thermal power of 0.0435W, saving 75% of energy.

[0033] Fourthly, the present invention deposits metal electrodes on a substrate based on the MCED electrochemical deposition principle, so that the electrodes can have a complex three-dimensional structure and can reach a micron-level size, with better adaptability.

[0034] Fifth, compared with the existing photolithography technology for preparing flow sensors, which requires the sensor to be prepared on a silicon wafer substrate, this patent can perform MCED electrochemical deposition of any depositable metal electrode on any conductive substrate, making the sensor substrate diverse.

[0035] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The front view of the arch electrode structure deposited by MCED deposition technology;

[0037] Figure 2 Schematic diagram of the principle of the droplet confinement electrodeposition technology (MCED) used in the present invention;

[0038] Figure 3 Schematic diagram of the deposition of a metal film on a substrate using physical vapor deposition;

[0039] Figure 4 A schematic diagram of a process of depositing metal pillars on a conductive substrate using the MCED method of the present invention;

[0040] Figure 5 A schematic diagram of a conductive substrate after metal pillars are deposited using the MCED method of the present invention;

[0041] Figure 6 A schematic diagram of a process of depositing a comb-type electrode on a conductive substrate using the MCED method of the present invention;

[0042] Figure 7 This is a main dimension diagram of the laminated electrode after modeling of the present invention;

[0043] Figure 8 A side dimensional diagram of the laminated electrode after modeling of the present invention;

[0044] Fig. 9 A front perspective view of the arch electrode modeled according to the present invention;

[0045] Fig.10 Top view of the electrode dimensions after modeling the arch electrode and the fitted electrode;

[0046] Fig.11 A side dimensional diagram of the arch electrode after modeling of the present invention;

[0047] Fig.12 The COMSOL model diagram after the arch electrode is imported into the finite element simulation software;

[0048] Fig.13 The COMSOL model diagram after the bonded electrode is imported into the finite element simulation software;

[0049] Fig.14 The simulation analysis curve diagram after meshing using the existing fitted electrode model when the air temperature is 25°C, the heating electrode temperature is 100°C, and the air flow rate is 0.1m / s, 0.4m / s, 0.7m / s, and 1.0m / s;

[0050] Fig.15 It is a simulation analysis curve diagram after meshing using the arch electrode model of the present invention when the air temperature is 25°C, the heating electrode temperature is 100°C, and the air flow rate is 0.1m / s, 0.4m / s, 0.7m / s and 1.0m / s;

[0051] Fig.16 It is a simulation analysis curve diagram after meshing using the arch electrode model of the present invention when the air temperature is 0°C, the heating electrode temperature is 100°C, and the air flow rate is 0.1m / s, 0.4m / s, 0.7m / s and 1.0m / s;

[0052] Fig.17 It is a simulation analysis curve diagram after meshing using the arch electrode model of the present invention when the air temperature is 0°C, the heating electrode temperature is 150°C, and the air flow rates are 0.1m / s, 0.4m / s, 0.7m / s and 1.0m / s.

[0053] Fig.18 It is a simulation analysis curve diagram after meshing using the arch electrode model of the present invention when the air temperature is 25°C, the heating electrode temperature is 150°C, and the air flow rate is 0.1m / s, 0.4m / s, 0.7m / s and 1.0m / s;

[0054] Fig.19It is a simulation analysis curve diagram after meshing using the arch electrode model of the present invention when the air temperature is 50°C, the heating electrode temperature is 100°C, and the air flow rate is 0.1m / s, 0.4m / s, 0.7m / s and 1.0m / s;

[0055] Fig. 20 It is a simulation analysis curve diagram after meshing using the arch electrode model of the present invention when the air temperature is 50°C, the heating electrode temperature is 150°C, and the air flow rates are 0.1m / s, 0.4m / s, 0.7m / s and 1.0m / s. DETAILED DESCRIPTION

[0056] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0057] Electrochemical deposition technology is a processing method that controls the electrochemical reaction conditions of the micro-region on the electrode surface and prepares metal or alloy materials and manufactures parts by atomic-level layer-by-layer stacking. It has the advantages of a wide range of materials, low processing temperature, easy shape control and high spatial resolution. Therefore, it has great development potential in metal micro-nano additive manufacturing. Electrochemical deposition technology can be divided into maskless deposition and masked deposition based on the principle. Masked deposition is represented by through-mask electroplating (Through-mask Electroplating), instant masking plating (Instant Masking Plating, IMPlating), electrochemical fabrication (Electrochemical Fabrication, EFAB), and LIGA technology (Lithography, Electroforming, and Molding). It has the advantages of high precision and high repeatability, but its cost is high, the preparation cycle is long, and the mask often remains on the structure. Maskless electrochemical deposition is represented by localized electrochemical deposition (LECD), jet electrochemical deposition (Jet ECD), fluid force microscope electrodeposition (FluidFM Electrodeposition), and meniscus-confined electroplating (MCED). Masked deposition technology usually has higher forming accuracy and better surface quality, but it is difficult to manufacture truly three-dimensional complex microstructures. Maskless deposition technology has the potential to manufacture complex three-dimensional microstructures, but it is usually not as good as masked deposition technology in terms of surface quality and geometric accuracy. Therefore, maskless deposition technology is still an important method for preparing micro-nano structures. Among them, the droplet constrained electrodeposition technology (MCED) has become a research hotspot in electrochemical deposition technology because it does not require a mold, has the ability to print directly, and meets the requirements of multi-material manufacturing.

[0058] The MCED method is a type of electrochemical three-dimensional micro-deposition technology that relies on a micropipette nozzle filled with an electrolyte. The outlet diameter of the pipette nozzle is usually between hundreds of nanometers and microns. When this micropipette nozzle approaches the surface of the substrate, a continuous and stable meniscus (also called a curved liquid surface or liquid) can be formed between the nozzle outlet and the substrate. Under the action of an external electric field, a chemical reaction will occur inside the meniscus, thereby forming a metal with three-dimensional shape characteristics on the conductive substrate. By coordinating the withdrawal speed of the pipette away from the substrate surface and the growth rate of local deposition, the continuous growth of nanowires or microwires on the surface of the body can be achieved.

[0059] The system principle corresponding to the MCED method is as follows Figure 2 As shown in the figure, it mainly uses a glass probe drawn into a micron or nanometer diameter as a printing nozzle, a simple electrode wire as a counter electrode (CE), and a conductive substrate as a working electrode (WE). When a potential difference is applied between the substrate and the electrode wire, electron transfer is triggered in the droplet bridge contact area, causing electrodeposition to occur only in the area covered by the droplet bridge, thereby achieving localized printing of the target structure. Its system principle.

[0060] In view of the excellent performance of MCED in printing simple vertical spatial structures, the MCED technology is extended from vertical structures to planar structure printing, and complex three-dimensional spatial structures are generated in the form of stacking. This method can be used to prepare micro flow sensor electrodes to meet the requirements of micro sensor structures. Therefore, in view of the current method of making micro flow sensor chips, which is mainly made by photolithography technology, with high production cost, complex process and high operation requirements, the present invention proposes a method for preparing micro flow sensors based on the MCED electrochemical deposition principle, which reduces the cost and difficulty of preparing micro flow sensors and provides a new method for preparing micro flow sensors.

[0061] Example 1

[0062] A method for preparing an arch electrode for a calorimetric micro-flow sensor comprises the following steps:

[0063] Step 1: Prepare a conductive substrate, such as preparing a sensor chip on a silicon wafer.

[0064] 1. Silicon wafers need to go through rigorous pre-treatment steps to ensure that their surfaces are clean, flat and free of contaminants. This usually includes chemical cleaning, ultrasonic cleaning and possibly a vacuum drying process to thoroughly remove grease, dust and other impurities on the surface of the silicon wafer.

[0065] 2. Send the silicon wafer into a highly clean vacuum chamber. In the vacuum chamber, the selected metal material is heated to a high temperature through a precisely controlled heating element or a high-energy particle beam (such as an electron beam or an ion beam), causing it to evaporate or sputter into gaseous metal atoms or ions. These gaseous metal atoms or ions diffuse freely in the vacuum and are adsorbed and condensed on the surface of the silicon wafer. By adjusting the deposition parameters (such as deposition temperature, gas pressure, deposition time, and selection of metal materials, etc.), the substrate layer (such as Figure 3 The thickness, composition and microstructure of the metal film on the substrate are shown in Figure 5.

[0066] Step 2: Connect the substrate to the negative electrode and deposit metal pillars on the metal film by MCED electrochemical deposition method.

[0067] 1. Prepare the electrolyte solution for metal deposition and add it into the pipette. Connect the metal wire into the pipette and connect the metal wire to the positive electrode, for example Figure 4 Depositing metal columns, when the electrolyte solution in the pipette contacts the conductive substrate, the metal cations in the electrolyte solution will gain electrons and be reduced to metals deposited on the substrate, and the metal in the pipette will lose electrons and be oxidized to metal cations to supplement the lost metal cations in the pipette.

[0068] 2. Deposit metal pillars by continuously changing the height of the pipette. When the predetermined height is reached, stop energizing and remove the pipette to obtain the metal pillar structure in the electrode structure (such as Figure 5 shown).

[0069] Step 3: Deposit the comb electrode structure laterally above the metal pillars.

[0070] 1. Connect the substrate to the negative electrode, add the electrolyte solution of the deposited metal into the pipette, connect the metal in the pipette to the positive electrode, and then align the pipette nozzle with the metal column (such as Figure 6 shown).

[0071] 2. According to the shape and size of the combing electrode structure, move the pipette according to the parameters. Finally, after moving the pipette to the metal column on the other side, stop the power supply and move the pipette away to complete the production of the horizontal combing electrode structure (such as Figure 7 shown).

[0072] Compared with the prior art, this solution has the following effects:

[0073] 1. Different electrode manufacturing methods: The existing micro-calorimetric flow sensor manufacturing method is mainly prepared by photolithography technology. This patent uses the MCED electrochemical deposition principle to deposit metal electrodes on the substrate, and can reach micron-level size.

[0074] 2. Different electrode structure: In the existing calorimetric flow sensor, the electrode is placed above the silicon wafer substrate. The electrode of this patent is different from the traditional electrode structure and adopts an arched structure. This structure is suitable for the MCED electrochemical principle deposition structure, and this structure improves the sensor performance better than the traditional sensor electrode structure.

[0075] 3. Diverse sensor substrates: The existing photolithography technology for preparing flow sensors requires the sensor to be prepared on a silicon wafer substrate. This patent can perform MCED electrochemical deposition of any depositable metal electrode on any conductive substrate.

[0076] 4. Electrodes can have complex three-dimensional structures: The basic principle of photolithography is to use the characteristics of light to transfer the pattern to the substrate to be processed through steps such as light source, mask, photosensitive material and development. Therefore, the lack of longitudinal structure of sensor electrodes prepared by photolithography technology limits the diversity of sensor electrode structures. However, due to the principle of MCED electrochemical deposition, the deposited metal electrodes can have the ability to produce complex three-dimensional structures, which improves the diversity of sensor electrode structure preparation.

[0077] 5. Better cost-effectiveness: Currently, photolithography equipment is complex and expensive, including photolithography machines, masks, light sources, etc., with high investment costs; operating costs include electricity consumption, photoresist consumption, mask production costs, and equipment maintenance costs, which are relatively high. Electrochemical deposition equipment is relatively simple, usually including electrolytic cells, power supplies, stirring devices, etc., with lower investment costs; operating costs mainly include electricity consumption, electrolyte consumption, and equipment maintenance costs, which are relatively low. Photolithography technology is suitable for high-precision, small-batch production or R&D stages, while electrochemical deposition technology is suitable for large-scale production and can meet the needs of low cost and high efficiency.

[0078] Example 2

[0079] like Figure 1 , Fig. 9 As shown, an electrode of a calorimetric micro flow sensor, the electrode is configured to be an arched structure, the lowest point of the arched structure is 200 μm away from the electrode mounting plate (i.e., substrate 1), and the electrode is configured to include:

[0080] Two metal pillars 2 are arranged opposite to each other on the electrode mounting plate;

[0081] A comb-type electrode 3 provided at the upper end of each metal column and used to connect two metal columns into an integrated structure;

[0082] The height of the metal column is 200 μm and the diameter is 50 μm. The overall size of the comb electrode is 650 μm×300 μm. The width of the electrode wire in the comb electrode is 50 μm and the height is 20 μm.

[0083] In this example, an electrochemically deposited sensor electrode structure is designed. Traditional flow sensors will make hollow structures to improve sensor performance. This design prepares an arched electrode structure in accordance with the MCED electrochemical deposition principle, which not only meets the electrode structure distribution of the calorimetric sensor, but also improves the sensor performance.

[0084] Simulation comparison example:

[0085] (i) In order to compare the performance of the conventional micro calorimetric flow sensor with the micro flow sensor of the patent, two sensor models were modeled using modeling software. The base size of both sensors was 2 mm × 1 mm × 0.5 mm, and the electrode was a comb structure with a width of 50 μm and a height of 20 μm, wherein the overall length and width of the comb structure was 650 μm × 300 μm.

[0086] 1. Modeling of traditional micro-calorimetric flow sensor: The cavity structure dimensions of the hollow structure sensor are as follows: the length and width of the cavity mouth are 650μm×50μm, the cavity length is 1800μm, the cavity depth is 200μm, the distance between the cavity bottom and the cavity top is 150μm, the distance between the cavity mouths on both sides of the temperature measuring electrode area is 550μm, and the distance between the cavity mouths on both sides of the heating electrode is 500μm. Among them, the size parameters of the fitted electrode model in the traditional sensor are as follows Figure 3-Figure 4 , Figure 6 shown.

[0087] 2. Modeling of a new calorimetric flow sensor: The sensor uses an arched comb-shaped electrode (the electrode size is consistent with that of the traditional sensor), the electrode height is 200 μm, and the cylindrical electrode with a diameter of 50 μm is located below the comb-shaped electrode. The size parameters of the arched electrode in the sensor model of the present invention are as follows: Figure 5-Figure 7 shown.

[0088] (ii) After the model is built, the model is imported into COMSOL finite element simulation software, and a free air volume with a height of 0.5 mm is set above the model, wherein the substrate material is set as a silicon wafer, and the electrode material is set as a metal electrode. Figure 13-14 COMSOL model of the sensor.

[0089] 1. After the model is established, air flow rates of 0.1m / s, 0.4m / s, 0.7m / s and 1m / s are introduced on one side. The thermal power of the heating electrode in the middle of the traditional sensor and the new sensor is set to 0.175W and 0.0435W respectively. The heating electrode can generate a temperature of 150℃. After the model is meshed, simulation analysis is performed to obtain the following Figure 14-15 The temperature distribution from Figure 14 to Figure 15It can be seen that after the heating electrodes produce similar temperatures, the same gas flow rate is introduced, and the temperature difference of the temperature measuring electrodes on both sides is 6°C and 55°C respectively, which increases the temperature difference by 49°C. This is because the contact area between the temperature measuring electrode and the substrate is small, which greatly reduces the temperature diffusion of the temperature generated by the heating electrode on the substrate surface, so that the temperature source of the temperature measuring electrode is changed by the gas flow, and the temperature difference of the temperature measuring electrodes on both sides at the same flow rate is increased. The temperature difference change is more sensitive, and the sensor performance is improved. At the same time, the arch structure sensor can find the placement position of the temperature measuring electrode 4 through the simulation method. At air flow rates of 0.1m / s, 0.4m / s, 0.7m / s and 1m / s, the distance from the central heating electrode 5 is 200 to 250μm, which is most suitable.

[0090] The arch electrode of the present invention is simulated at different air temperatures of 0°C, 25°C, and 50°C and different heating electrode temperatures of 100°C and 150°C, and the air flow rates of 0.1m / s, 0.4m / s, 0.7m / s, and 1.0m / s are passed. It can be seen from the simulation test that the comparison of the results of the simulation test shows that (such as Figure 16-Figure 20 ), when the temperature measuring electrodes on both sides are about 238μm away from the central heating electrode, they can have a stable temperature difference with obvious temperature difference differentiation, which makes the measurement resolution and sensitivity better.

[0091] The above solution is only an illustration of a preferred embodiment, but is not limited thereto. When implementing the present invention, appropriate replacement and / or modification can be performed according to user needs.

[0092] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and the embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily realized. Therefore, without departing from the general concept defined by the claims and equivalent scope, the present invention is not limited to the specific details and the illustrations shown and described here.

Claims

1. An electrode for a calorimetric micro-flow sensor, characterized in that: The electrode is configured to be an arch structure, and a distance of 200 μm is formed between the lowest point of the arch structure and the electrode mounting plate.

2. The electrode of the calorimetric micro-flow sensor according to claim 1, characterized in that: The electrode is configured to include: Two metal pillars are arranged opposite to each other on the electrode mounting plate; A comb-type electrode disposed at the upper end of each metal column and used to connect two metal columns into an integrated structure; Wherein, the height of the metal column is 200 μm and the diameter is 50 μm.

3. The electrode of the calorimetric micro-flow sensor according to claim 2, characterized in that: The overall size of the comb-type electrode is 650 μm×300 μm, and the electrode wire in the comb-type electrode has a width of 50 μm and a height of 20 μm.

4. An electrode preparation method, which is used in the preparation of an electrode of a calorimetric micro-flow sensor as claimed in any one of claims 1 to 3, characterized in that: include: S1. preparing a conductive substrate; S2, connecting the substrate to the negative electrode, and depositing metal pillars on the metal film by MCED electrochemical deposition method; S3. Depositing a comb-type electrode structure laterally above the metal pillar.

5. The electrode preparation method according to claim 4, characterized in that: In S1, the conductive substrate is prepared by: S10, pre-treating the base material to remove grease, dust and other impurities on the surface of the base material; S11. Place the base material in a vacuum chamber of a predetermined cleanliness level, and heat the selected metal material so that the metal atoms or ions that are evaporated or sputtered into gaseous form can be adsorbed and condensed on the surface of the silicon wafer, thereby obtaining a metal film layer on the base material through physical vapor deposition.

6. The electrode preparation method according to claim 4, characterized in that: In S2, a method of depositing a metal pillar includes: S20, adding an electrolyte solution for preparing deposited metal into a pipette, and inserting a metal wire into the pipette and connecting the metal wire to the positive electrode; S21. When the electrolyte solution in the pipette contacts the conductive substrate, the metal ions in the electrolyte solution are reduced to metal by electrons and deposited on the substrate, while the metal in the pipette loses electrons and is oxidized to metal ions, thereby replenishing the metal ions lost in the pipette; S22. Adjust the height of the pipette to deposit the metal column until the metal column reaches a predetermined height.

7. The electrode preparation method according to claim 4, characterized in that: In S3, during the lateral deposition of the comb electrode structure, the position of the deposition pipette is controlled by a multi-degree-of-freedom displacement component, and the multi-degree-of-freedom displacement component is communicatively connected to an external control terminal.

8. The electrode preparation method according to claim 4, characterized in that: The invention also includes simulating the performance of the arch electrode through simulation, wherein the simulation process includes: S4. Modeling the structures of the fitted electrode and the arch electrode respectively by using modeling software; S5, importing each electrode model after modeling into COMSOL finite element simulation software, and setting each substrate material to silicon wafer and each electrode material to metal electrode, thus completing the establishment of the simulation model; S6. Free air with a height of 0.5 mm is set above each simulation model, and air with different flow rates is introduced on one side. The same thermal power is set for the middle heating electrode of the corresponding sensor of the fitted electrode and the arch electrode to achieve the same temperature of the heating electrode, and the heating power is compared to complete the simulation analysis after the model is meshed; S7. Through simulation analysis, the optimal distance between the temperature measuring electrodes on both sides and the central heating electrode at different flow rates is obtained.

9. The electrode preparation method according to claim 8, characterized in that: At an air temperature of 0 to 50°C and an air velocity of 0 to 1 m / s, the distance between the temperature measuring electrodes on both sides and the central heating electrode is 200 to 250 μm.

10. The electrode preparation method according to claim 9, characterized in that: By simulating different air temperatures of 0℃, 25℃, and 50℃ and different heating electrode temperatures of 100℃ and 150℃, and passing air flow rates of 0.1m / s, 0.4m / s, 0.7m / s, and 1.0m / s, it was found that the distance between the temperature measuring electrodes on both sides and the central heating electrode is preferably 238μm.

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