A MEMS-based electrochemical measurement sensor for material corrosion, its preparation method, and an electrochemical measurement device for material corrosion

Abstract

The present application provides a MEMS-based electrochemical measurement sensor for material corrosion, its preparation method, and an electrochemical measurement device for material corrosion, which relates to the technical field of material corrosion sensors. The sensor includes: a working electrode - auxiliary electrode module, which includes a first silicon substrate, a working electrode, and an auxiliary electrode. The first silicon substrate is provided with a recessed portion. The working electrode is disposed on one side and the bottom of the inner wall of the recessed portion, and the auxiliary electrode is disposed on the opposite side and the bottom of the inner wall of the recessed portion. The working electrode, the auxiliary electrode, and the recessed portion form an accommodation space; a reference electrode module, which includes a second silicon substrate and a reference electrode. The reference electrode is disposed on one side of the second silicon substrate and forms a protruding portion, and the second silicon substrate is provided with a through hole; the protruding portion is disposed in the accommodation space, and the first silicon substrate and the second silicon substrate are fixedly connected. The sensor provided by the present application can realize in-situ real-time high-throughput online acquisition and mining analysis of corrosion data during the evaluation process of material service failure.

Description

Technical Field

[0001] The present application relates to the field of material corrosion sensors, and in particular, to a MEMS-based electrochemical measurement sensor for material corrosion, a preparation method thereof, and an electrochemical measurement device for material corrosion. Background Art

[0002] The natural environment corrosion of materials is very complex with numerous influencing factors and is difficult to simulate in the laboratory. Only through on-site tests and observations at long-term continuous field test sites can actual corrosion data be obtained. The high-throughput corrosion data acquisition, analysis, and mining of material environmental corrosion failure have always been a frontier hot issue. Related work has a history of over a hundred years, and electrochemical resistance sensors, inductive sensors, galvanic sensors, alternating current impedance sensors, etc. have been successively established, and relevant data accumulation, mining, and analysis work have been carried out. The corresponding sensor technologies mainly focus on structural and solid-state sensors, and the on-site application of such sensors is very limited. Therefore, to deploy material sensors on a large scale and obtain material corrosion data, material corrosion sensors with smaller size, lower cost, lower power consumption, and at the device level are required.

[0003] Micro-Electro-Mechanical System (MEMS) material corrosion chips and sensors are intelligent micro-electro-mechanical sensor systems that can monitor the environmental corrosion rate of materials and perform artificial intelligence processing and analysis on environmental corrosion data. This sensor system has an MEMS material intelligent corrosion chip and an embedded ASIC data processing chip. Compared with traditional sensors, it has the characteristics of small size, light weight, low cost, high reliability, suitability for mass production, easy integration, and easy implementation of intelligence. In recent years, the development of MEMS sensors and artificial intelligence data mining technology has been very rapid. However, there is no development technology for micro-electro-mechanical systems and corresponding corrosion chips in the evaluation process of material service failure. Traditional sensors have the characteristics of large volume, high power consumption, poor stability, and low response sensitivity, which seriously hinder the large-area application of material corrosion sensors and the development of material corrosion genetic engineering technology. In the field of material corrosion sensors, realizing chip-level material corrosion sensors, reducing monitoring costs, and improving monitoring accuracy have always been difficult problems in the corrosion field and the international academic forefront and technological competition focus in the field of material corrosion genetic engineering. The key lies in developing MEMS material corrosion chips and sensors to achieve in-situ real-time high-throughput online acquisition and mining analysis of corrosion data in the evaluation process of material service failure. Summary of the Invention

[0004] The purpose of the present application is to provide a MEMS-based electrochemical measurement sensor for material corrosion, a preparation method thereof, and an electrochemical measurement device for material corrosion to solve the above problems.

[0005] To achieve the above object, the present application adopts the following technical solutions:

[0006] A MEMS-based electrochemical measurement sensor for material corrosion, comprising:

[0007] A working electrode - counter electrode module, the working electrode - counter electrode module includes a first silicon substrate, a working electrode and a counter electrode. The first silicon substrate is provided with a recess. The working electrode is disposed on one side and the bottom of the inner wall of the recess, and the counter electrode is disposed on the opposite side and the bottom of the inner wall of the recess. The working electrode, the counter electrode and the recess form an accommodation space;

[0008] A reference electrode module, the reference electrode module includes a second silicon substrate and a reference electrode. The reference electrode is disposed on one side of the second silicon substrate and forms a convex portion. The second silicon substrate is provided with a through hole along the thickness direction;

[0009] The convex portion is disposed in the accommodation space and the working electrode, the counter electrode and the reference electrode are not connected to each other. The first silicon substrate and the second silicon substrate are fixedly connected;

[0010] The distance between the working electrode and the reference electrode is 1000 - 2000 μm (which can be 1000 μm, 1100 μm, 1200 μm, 1300 μm, 1400 μm, 1500 μm, 1600 μm, 1700 μm, 1800 μm, 1900 μm, 2000 μm or any value between 1000 - 2000 μm), and the distance between the working electrode and the counter electrode is 1000 - 5000 μm (which can be 1000 μm, 1500 μm, 2000 μm, 2500 μm, 3000 μm, 3500 μm, 4000 μm, 4500 μm, 5000 μm or any value between 1000 - 5000 μm).

[0011] The corrosion electrochemical three - electrode system after connection should conform to the measurement rules of corrosion electrochemistry, that is, it satisfies the stacking order of working electrode - reference electrode - counter electrode, and the working electrode and the reference electrode should be as close as possible to reduce the ohmic resistance during the corrosion electrochemical measurement.

[0012] Preferably, the cross - sections of the working electrode and the counter electrode are L - shaped.

[0013] Preferably, the working electrode, the counter electrode and the reference electrode are prepared from the target metal material to be measured.

[0014] Preferably, there are multiple pairs of the accommodation space and the convex portion.

[0015] The present application also provides a preparation method for a material corrosion electrochemical measurement sensor based on MEMS, including:

[0016] Coat a first semiconductor photoresist on one side of the first silicon substrate and perform a first soft bake, then use an electrolytic cell mask plate to expose, develop, and dissolve under corresponding ultraviolet light to form an exposed substrate area; etch the recess in the exposed substrate area by ion etching;

[0017] Remove the residual first semiconductor photoresist, coat a second semiconductor photoresist on the side of the first silicon substrate with the recess and perform a second soft bake, then use a working electrode mask plate to expose, develop, and dissolve under corresponding ultraviolet light to form a working electrode pattern; form a working electrode layer at the position of the working electrode pattern by sputtering or electroplating the target metal material to be measured;

[0018] Remove the residual second semiconductor photoresist and metal material to obtain the working electrode;

[0019] Coat a third semiconductor photoresist on the side of the first silicon substrate with the recess and perform a third soft bake, then use an auxiliary electrode mask plate to expose, develop, and dissolve under corresponding ultraviolet light to form an auxiliary electrode pattern; form an auxiliary electrode layer at the position of the auxiliary electrode pattern by sputtering or electroplating the target metal material to be measured;

[0020] Remove the residual third semiconductor photoresist and metal material to obtain the auxiliary electrode; that is, obtain the working electrode - auxiliary electrode module;

[0021] Set a reference electrode layer on one side surface of the second silicon substrate by sputtering or electroplating, then coat a fourth semiconductor photoresist and perform a fourth soft bake, and then use an auxiliary electrode mask plate to expose, develop, and dissolve under corresponding ultraviolet light to form a reference electrode pattern; etch at the position of the reference electrode pattern by ion etching, and remove the residual fourth semiconductor photoresist and metal material to obtain the reference electrode;

[0022] Coat a fifth semiconductor photoresist on the side of the second silicon substrate away from the reference electrode and perform a fifth soft bake, then use a via mask plate to expose, develop, and dissolve under corresponding ultraviolet light to form a via pattern; etch at the position of the via pattern by ion etching to obtain the via; that is, obtain the reference electrode module;

[0023] Bond the working electrode - auxiliary electrode module and the reference electrode module by silicon - silicon bonding to obtain the material corrosion electrochemical measurement sensor based on MEMS.

[0024] Preferably, the first silicon substrate and the second silicon substrate are cleaned before use.

[0025] Preferably, the temperatures of the first soft bake, the second soft bake, the third soft bake, the fourth soft bake, and the fifth soft bake are each independently 90 - 110 °C.

[0026] Preferably, before the silicon - silicon bonding, the first silicon substrate and the second silicon substrate are surface - cleaned;

[0027] The silicon - silicon bonding adopts a heat - annealing treatment method.

[0028] This application also provides a material corrosion electro - chemical measurement device, including the MEMS - based material corrosion electro - chemical measurement sensor described above.

[0029] Preferably, the material corrosion electro - chemical measurement device further includes a substrate lead frame;

[0030] The working electrode, the auxiliary electrode, and the reference electrode are electrically connected to the substrate lead frame.

[0031] Compared with the prior art, the beneficial effects of this application include:

[0032] The MEMS - based material corrosion electro - chemical measurement sensor provided by this application combines the working - electrode - auxiliary - electrode module and the reference - electrode module, and forms a three - electrode system for material corrosion electro - chemical measurement through a bonding method. This sensor has the characteristics of miniaturization and low cost, and its preparation method is mature, which is convenient for large - scale integration and batch manufacturing, and can meet the needs of on - line monitoring of moisture or liquid - phase corrosion electro - chemistry for different specifications and different materials. The width of the electrolytic cell (recess) should be greater than the width of the reference electrode to ensure that the reference electrode can be smoothly placed into the electrolytic cell groove; the number, size, and position of the electrolytic cells can be adjusted according to actual needs, and the number of the three - electrode systems can also be adjusted according to actual needs. The working electrode, the reference electrode, and the auxiliary electrode can be replaced according to the actual needs of material corrosion electro - chemical measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] To more clearly illustrate the technical solutions of the embodiments of this application, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as limiting the scope of this application.

[0034] Figure 1 Schematic diagram of the preparation process of the working - electrode - auxiliary - electrode module provided for the embodiment;

[0035] Figure 2 Schematic diagram of the preparation process of the reference - electrode module provided for the embodiment;

[0036] Figure 3 Bonding schematic diagram of the MEMS-based electrochemical measurement sensor for material corrosion provided for the embodiment;

[0037] Figure 4 Schematic diagram of the substrate lead frame provided for the embodiment;

[0038] Figure 5 Top view of the material corrosion electrochemical measurement device provided for the embodiment;

[0039] Figure 6 Stereogram of the material corrosion electrochemical measurement device provided for the embodiment;

[0040] Figure 7 Open circuit potential test result graph of the sensor obtained in the embodiment;

[0041] Figure 8 Electrochemical impedance spectroscopy test result graph of the sensor obtained in the embodiment;

[0042] Figure 9 Weak polarization test result graph of the sensor obtained in the embodiment;

[0043] Figure 10 Electrochemical impedance spectroscopy test result graph of the sensor obtained in Comparative Example 1;

[0044] Figure 11 Electrochemical impedance spectroscopy test result graph of the sensor obtained in Comparative Example 2.

[0045] Reference numerals:

[0046] 1 - First silicon substrate; 2 - Second silicon substrate; 3 - Working electrode; 4 - Auxiliary electrode; 5 - Reference electrode; 6 - Electrochemical cell; 7 - Substrate lead frame; 8 - Bonding wire; 9 - Pad; 10 - Through hole. Detailed implementation manners

[0047] The following will describe the implementation scheme of the present application in detail in combination with specific embodiments. However, those skilled in the art will understand that the following embodiments are only used to illustrate the present application and should not be regarded as limiting the scope of the present application. For those conditions not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments whose manufacturers are not specified, they are all conventional products that can be obtained through commercial purchase.

[0048] Embodiment

[0049] This embodiment provides a MEMS-based electrochemical measurement sensor for material corrosion, and its preparation process is as follows:

[0050] As Figure 1As shown in the figure, (1) The preparation processes of the auxiliary electrode and the working electrode are as follows:

[0051] 1.1 Use a silicon wafer with a diameter of 100 mm and a thickness of 525 μm as the first substrate silicon wafer. First, clean the surface of the first substrate silicon wafer with deionized water; subsequently, clean the silicon wafer with a cleaning solution composed of 25% hydrogen peroxide, 25% ammonia water, and pure water in a volume ratio of 1:1:20 for about 270 s; then continue to clean with a cleaning solution composed of 30% hydrochloric acid, 25% hydrogen peroxide, and pure water in a volume ratio of 1:1:20 for 250 s; then rinse the silicon wafer with a large amount of deionized water and dry it with a high-speed spin-drying device, and the spin-drying process time is 290 - 310 s.

[0052] 1.2 Coat the silicon wafer with SU-8 semiconductor ultraviolet photoresist. Spin-coat the SU-8 photoresist components on the substrate at a speed of 1200 r / min, and control the spin-coated thickness at 180 microns. After heating the silicon wafer on a uniform heating plate at 100 °C for 100 s for sufficient drying, transfer it to the lithography machine, and load the mask plate of the electrolytic cell onto the lithography machine for lithography and development. The ultraviolet radiation dose is 200 mJ / cm 2 Expose for 6 - 12 seconds.

[0053] 1.3 Then, develop it fully with SU-8 developer until the pattern of the corrosion electrolytic cell is clearly and completely presented;

[0054] 1.4 Then, etch the silicon wafer by femtosecond laser etching method to remove the exposed substrate area, and etch downward in the exposed substrate area to form an electrolytic cell for the corrosion electrolyte, which is used as the electrolytic cell for the three-electrode reaction of corrosion electrochemistry. The etching rate is about 8 μm / min, and the total etching depth is 200 μm.

[0055] 1.5 Repeat step 1.1 to remove the residual photoresist on the silicon wafer, then clean it with deionized water and dry it for standby;

[0056] 1.6 Repeat steps 1.2 to 1.4. The difference in this step is that the mask plate used in this step is the mask plate of the working electrode. After exposure and development, dissolve the pattern in the working electrode area to form the pattern of the working electrode in the electrolytic cell;

[0057] 1.7 Use the magnetron sputtering method to form the working electrode required for the measurement of material corrosion electrochemistry. In this example, the working electrode uses metallic copper as the target material for magnetron sputtering and also serves as the anode for the measurement of this material corrosion electrochemistry. The sputtering thickness is about 20 μm;

[0058] 1.8 Repeat step 1.1 to remove the residual photoresist on the first substrate silicon wafer and the working electrode material of magnetron sputtering, then clean it with deionized water and dry it for standby;

[0059] 1.9 Repeat steps 1.2 to 1.4. The difference in this step is that the mask used is the mask for the auxiliary electrode. After exposure and development, the pattern in the auxiliary electrode area is dissolved to form the pattern of the auxiliary electrode in the electrolytic cell;

[0060] 1.10 Prepare the auxiliary electrode required for the electrochemical measurement of material corrosion by magnetron sputtering. In this example, a Pt target is used, and the sputtering thickness is about 20 μm;

[0061] 1.11 Repeat step 1.1 to remove the remaining photoresist on the wafer and the sputtered auxiliary electrode material on the photoresist. Then, wash with deionized water and dry for standby. In this way, the electrolytic cell, working electrode, and auxiliary electrode on the first substrate have been successfully prepared.

[0062] As Figure 2 shown, the preparation process of the reference electrode is as follows:

[0063] 2.1 Use a silicon wafer with a diameter of 100 mm and a thickness of 525 μm as the second substrate silicon wafer. First, wash the surface of the second substrate silicon wafer with deionized water; subsequently, wash the silicon wafer with a cleaning solution composed of 25% hydrogen peroxide, 25% ammonia water, and deionized water in a volume ratio of 1:1:20 for about 260 s; then continue to wash with a cleaning solution composed of 30% hydrochloric acid, 25% hydrogen peroxide, and deionized water in a volume ratio of 1:1:20 for 250 s; then rinse the silicon wafer with a large amount of deionized water and dry it with a high-speed spin-drying device. The spin-drying process takes 290 s;

[0064] 2.2 Prepare the reference electrode required for the electrochemical measurement of material corrosion by magnetron sputtering. In this example, an Ag reference electrode is used;

[0065] 2.3 Coat the silicon wafer with SU-8 semiconductor ultraviolet photoresist. Spin-coat the SU-8 photoresist component on the substrate at a speed of 1200 r / min, and control the spin-coating thickness at 180 microns. Transfer the silicon wafer to a hotplate and heat it at 100 °C for 100 s for sufficient drying, and then transfer it to a lithography machine. Load the mask of the reference electrode onto the lithography machine for lithography and development. The ultraviolet radiation dose is 200 mJ / cm 2 for 10 seconds of exposure.

[0066] 2.4 Then, develop it thoroughly with SU-8 developer until the pattern of the reference electrode is clearly and completely presented;

[0067] After 2.5, the silicon wafer is etched by deep silicon etching to remove the exposed substrate area, and a groove is etched downward in the exposed substrate area as the reference electrode for the three-electrode reaction. The etching rate is about 8 μm / min, and the total etching depth is 200 μm.

[0068] Repeat step 1.1 to remove the residual photoresist on the silicon wafer, then wash it with deionized water, dry it, and set it aside; thus, an Ag reference electrode is prepared.

[0069] On the side of the second substrate silicon wafer away from the reference electrode, apply a semiconductor photoresist and perform soft baking. Use SU-8 semiconductor ultraviolet photoresist to coat the silicon wafer. Spin-coat the SU-8 photoresist component on the substrate at a speed of 1200 r / min, and control the spin-coating thickness to 180 microns. Use a uniform heating plate to heat the silicon wafer at 100 °C for 100 s to fully dry it, then transfer it to a lithography machine, and load the via mask onto the lithography machine for lithography and development. The ultraviolet radiation dose is 200 mJ / cm 2 Perform 10-second exposure.

[0070] After that, use SU-8 developer to develop it fully to present the via pattern completely and clearly;

[0071] Etch the silicon wafer by deep silicon etching to remove the exposed substrate area, and etch a through hole downward in the exposed substrate area;

[0072] Repeat step 1.1 to remove the residual photoresist on the silicon wafer, then wash it with deionized water, dry it, and set it aside; thus, a through hole is obtained.

[0073] (3) Silicon-silicon bonding

[0074] 3.1 Perform silicon-silicon bonding on the first substrate silicon wafer with a working electrode, an auxiliary electrode, and an electrolytic cell and the second substrate silicon wafer with a reference electrode. Before bonding, first perform surface cleaning on the first substrate silicon wafer and the second substrate silicon wafer using the RCA process to increase the surface electrostatic tension of the silicon wafers; prepare the A-component solution in the RCA process. The solution is a mixed solution of ammonia water, hydrogen peroxide, and water (ammonia water: H2O2: H2O = 1:1:6), heat it to 80 degrees Celsius, immerse the substrate silicon wafer in the A-component solution for 15 minutes, then take it out and rinse it with deionized water; configure the B-component solution in the RCA process. The solution is a mixed solution of hydrochloric acid, hydrogen peroxide, and water (HCl: H2O2: H2O = 1:1:5); immerse the substrate silicon wafer in the B-component solution for 15 minutes, then take it out and rinse it with deionized water; subsequently, rinse the two cleaned substrate silicon wafers in a 2% diluted HF solution for 30 s to completely remove the intrinsic oxide layer on the substrate silicon wafers, then rinse and spin-dry them with deionized water, and completely bond the two substrate silicon wafers together at room temperature, ensuring that the bonding surface is flat and free of impurities;

[0075] 3.2 As Figure 3 shown, through high-temperature annealing treatment at 250 °C, physical and chemical reactions occur at the silicon-silicon bonding interface to form chemical covalent bond connections, enhancing the bonding strength so that the first substrate and the second substrate form an integral body, the unbonded rate is less than 0.5%, and the bonding strength is greater than 15 MPa.

[0076] The obtained corrosion electrochemistry sensor includes: a working electrode - auxiliary electrode module and a reference electrode module;

[0077] The working electrode - auxiliary electrode module includes a first silicon substrate 1, and the first silicon substrate is provided with a recess; the reference electrode module includes a second silicon substrate 2; the first silicon substrate 1 and the second silicon substrate 2 are fixedly connected. The working electrode 3 is arranged on the left side of the inner wall and the left side of the bottom of the recess, and is integrally L-shaped; the auxiliary electrode 4 is arranged on the right side of the inner wall and the right side of the bottom of the recess, and is integrally L-shaped; the working electrode 3, the auxiliary electrode 4, and the recess form an accommodating space; the reference electrode 5 is arranged on one side of the second silicon substrate 2 and forms a convex part, the reference electrode 5 is arranged in the accommodating space, and the working electrode 3, the auxiliary electrode 4, and the reference electrode 5 are not connected to each other. The recess serves as the electrolytic cell 6.

[0078] This embodiment also provides a material corrosion electrochemistry measurement device, including the above-mentioned MEMS-based material corrosion electrochemistry measurement sensor and a substrate lead frame 7 (as Figure 4 shown); bonding wires 8 are arranged on the substrate lead frame 7, and each bonding wire 8 is respectively connected to the working electrode 3, the auxiliary electrode 4, and the reference electrode 5.

[0079] Its preparation method includes - wire bonding:

[0080] 4.1 Design a substrate lead frame 7 made of copper-nickel alloy suitable for electrochemical measurement of MEMS corrosion. After cutting the bonded silicon wafer, place it on the frame. To ensure the bonding quality between the frame and the working electrode 3, auxiliary electrode 4, and reference electrode 5 on the silicon wafer, use a plasma cleaning device before bonding. At an argon flow rate of 10 ml / min, clean for 10 s at a power of 200 W to achieve ion cleaning of the silicon wafer and the frame.

[0081] 4.2 Adopt the copper wire bonding process to precisely bond the working electrode 3, auxiliary electrode 4, and reference electrode 5 to the substrate lead frame 7 made of copper-nickel alloy on the pad 9, realizing the electrical interconnection between the MEMS chip and the substrate and the information intercommunication between chips.

[0082] As Figure 5 and Figure 6 shown, two through holes 10 are opened in the second silicon substrate along the thickness direction for flowing fluid media such as electrolyte into the electrolytic cell 6.

[0083] 5 Sensor testing

[0084] 5.1 Place the sensor of this example in a high and low temperature alternating humidity chamber for electrochemical testing. The test contents include electrochemical open circuit potential, electrochemical impedance spectroscopy, and weak polarization testing. During the test, control the humidity at 100% and the temperature at 25 °C. Before the test, first place the system stably for 2 hours. The open circuit potential test time is 1200 s, and the results are as Figure 7 shown; the alternating current impedance scanning frequency is 0.01 Hz to 100 kHz, the applied interference voltage is 10 mV, and the alternating current impedance results are as Figure 8 shown. The polarization potential test is a scan of ±10 mV relative to the reference potential at a scanning frequency of 0.1667 Hz, and the results are as Figure 9 shown.

[0085] In this embodiment, the well-matched three-electrode system for corrosion electrochemistry should be arranged in the order of the working electrode, reference electrode, and auxiliary electrode. The distance between the working electrode and the reference electrode is 2000 μm. If the distance is too close, a charge shielding effect will occur, affecting the progress of the corrosion electrochemical reaction; if it is too far, a large ohmic drop will be generated, directly affecting the accuracy of electrochemical measurement. At the same time, the shapes of the working electrode and the auxiliary electrode are kept the same and arranged oppositely, with a distance of 4000 μm to form a good charge loop, fully ensuring the accuracy of corrosion electrochemical measurement. Therefore, this patent proposes a comparative example to measure the alternating current impedance, fully considering the influence of the electrode position and electrode spacing on the corrosion electrochemical measurement during the corrosion electrochemical measurement process.

[0086] Comparative example 1

[0087] Differing from the embodiment, the distance between the working electrode and the reference electrode is controlled to be 500 μm, the distance between the working electrode and the auxiliary electrode remains 4000 μm, and the electrochemical impedance is measured according to the corrosion electrochemistry measurement method in the embodiment. The results are as Figure 10 shown, Figure 10 the measured electrochemical impedance increases significantly. The main reason is that the gap is too small. On the one hand, an electrochemical shielding effect is generated. On the other hand, the gap is too small, which affects the infiltration of the solution under the action of electrostatic tension;

[0088] Comparative Example 2

[0089] Differing from the embodiment, the arrangement order of the working electrode, the reference electrode and the auxiliary electrode is controlled to be the working electrode, the auxiliary electrode and the reference electrode. The distance between the working electrode and the reference electrode is 4000 μm, and the distance between the working electrode and the auxiliary electrode is 2000 μm. The electrochemical impedance is measured according to the corrosion electrochemistry measurement method in the embodiment. The results are as Figure 11 shown, Figure 11 the impedance value corresponding to the low-frequency part in the measured electrochemical impedance increases significantly, indicating that there is a large ohmic drop in the system. This ohmic drop is because the distance between the working electrode and the reference electrode is too far. When the disturbance potential applied to the working electrode is used for impedance measurement, due to the existence of the ohmic drop, the actually applied potential decreases significantly. The corrosion electrochemistry measurement sensor based on MEMS materials provided by the present application has the characteristics of miniaturization and low cost, and the preparation method is mature, which can be conveniently integrated on a large scale and mass-produced, and can meet the needs of on-line monitoring of corrosion electrochemistry of different specifications and different materials.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A MEMS-based electrochemical measurement sensor for material corrosion, characterized in that, Comprising: A working electrode - counter electrode module, the working electrode - counter electrode module includes a first silicon substrate, a working electrode and a counter electrode. The first silicon substrate is provided with a recess. The working electrode is disposed on one side and the bottom of the inner wall of the recess, and the counter electrode is disposed on the opposite side and the bottom of the inner wall of the recess. The working electrode, the counter electrode and the recess form a receiving space; A reference electrode module, the reference electrode module includes a second silicon substrate and a reference electrode. The reference electrode is disposed on one side of the second silicon substrate and forms a protrusion. The second silicon substrate is provided with a through - hole along the thickness direction; The protrusion is disposed in the receiving space and the working electrode, the counter electrode and the reference electrode are not connected to each other. The first silicon substrate and the second silicon substrate are fixedly connected; The distance between the working electrode and the reference electrode is 1000 - 2000 μm, and the distance between the working electrode and the counter electrode is 1000 - 5000 μm; The cross - sections of the working electrode and the counter electrode are L - shaped; The working electrode, the counter electrode and the reference electrode are prepared from the target metal material to be measured; 2. The MEMS-based electrochemical measurement sensor for material corrosion according to claim 1, wherein There are multiple pairs of the receiving space and the protrusion; 3. A method for preparing a MEMS-based electrochemical measurement sensor for material corrosion as described in claim 1 or 2, characterized in that, Comprising: Coat a first semiconductor photoresist on one side of the first silicon substrate and perform a first soft bake. Then, use an electrolytic cell mask plate to perform exposure, development, and dissolution under corresponding ultraviolet light to form an exposed substrate area; Etch the recess in the exposed substrate area by ion etching; Remove the residual first semiconductor photoresist, coat a second semiconductor photoresist on the side of the first silicon substrate having the recess and perform a second soft bake. Then, use a working electrode mask plate to perform exposure, development, and dissolution under corresponding ultraviolet light to form a working electrode pattern; Deposit the target metal material to be measured at the position of the working electrode pattern by sputtering or electroplating to form a working electrode layer; Remove the residual second semiconductor photoresist and metal material to obtain the working electrode; Coat a third semiconductor photoresist on the side of the first silicon substrate having the recess and perform a third soft bake. Then, use a counter electrode mask plate to perform exposure, development, and dissolution under corresponding ultraviolet light to form a counter electrode pattern; Deposit the target metal material to be measured at the position of the counter electrode pattern by sputtering or electroplating to form a counter electrode layer; Remove the residual third semiconductor photoresist and metal material to obtain the counter electrode; thus, the working electrode - counter electrode module is obtained; Deposit a reference electrode layer on one side surface of the second silicon substrate by sputtering or electroplating. Then, coat a fourth semiconductor photoresist and perform a fourth soft bake. Then, use a counter electrode mask plate to perform exposure, development, and dissolution under corresponding ultraviolet light to form a reference electrode pattern; Etch at the position of the reference electrode pattern by ion etching, and remove the residual fourth semiconductor photoresist and metal material to obtain the reference electrode; A fifth semiconductor photoresist is coated on the side of the second silicon substrate away from the reference electrode and subjected to a fifth soft bake. Then, a via mask is used to perform exposure, development, and dissolution under corresponding ultraviolet light to form a via pattern; The via is etched at the position of the via pattern by ion etching; thus, the reference electrode module is obtained; The working electrode - auxiliary electrode module and the reference electrode module are subjected to silicon - silicon bonding to obtain the MEMS - based material corrosion electrochemical measurement sensor.

4. The preparation method of the MEMS-based electrochemical measurement sensor for material corrosion according to claim 3, characterized in that, The first silicon substrate and the second silicon substrate are cleaned before use.

5. The preparation method of the MEMS-based electrochemical measurement sensor for material corrosion according to claim 3, characterized in that The temperatures of the first soft bake, the second soft bake, the third soft bake, the fourth soft bake, and the fifth soft bake are each independently 90 - 110 °C.

6. The preparation method of the MEMS-based electrochemical measurement sensor for material corrosion according to any one of claims 3-5, characterized in that, Before the silicon - silicon bonding, the surfaces of the first silicon substrate and the second silicon substrate are cleaned; The silicon - silicon bonding adopts a heating annealing treatment method.

7. An electrochemical measurement device for material corrosion, characterized in that Including the MEMS - based material corrosion electrochemical measurement sensor according to claim 1 or 2.

8. The electrochemical measurement device for material corrosion according to claim 7, characterized in that, It further includes a substrate lead frame; The working electrode, the auxiliary electrode, and the reference electrode are electrically connected to the substrate lead frame.

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