Atmospheric corrosion sensor made of silicon-metal composite MEMS (Micro Electro Mechanical System) material, preparation method of atmospheric corrosion sensor and atmospheric corrosion detection equipment for material

Abstract

The invention provides a silicon-metal composite MEMS material atmospheric corrosion sensor, a preparation method thereof and material atmospheric corrosion detection equipment, and relates to the field of material corrosion sensors. The atmospheric corrosion sensor made of the silicon-metal composite MEMS material comprises a cathode and anode module and a cavity structure module, the cathode and anode module comprises a first substrate, a metal anode and a metal cathode, wherein the metal anode and the metal cathode are arranged on the surface of the first substrate and are independent from each other. The cavity structure module comprises a second substrate, the second substrate is provided with a sunken part and a through hole used for being communicated with the atmosphere of the test environment, the sunken part extends from the first side of the second substrate to the second side opposite to the first side, and the through hole extends from the surface of the second side to the bottom of the sunken part; the surface of the second side abuts against the surface of the first substrate, and the metal cathode and the metal anode are arranged in the concave part. The sensor provided by the invention is good in sensitivity, reliability and consistency.

Description

Technical Field

[0001] The present application relates to the technical field of material corrosion sensors, and in particular to a silicon-metal composite MEMS material atmospheric corrosion sensor, a preparation method thereof, and material atmospheric corrosion detection equipment. Background Art

[0002] Material corrosion is a major cause of failure in metal structural components, particularly in the microelectronics industry. Corrosion failure of electronic device materials directly threatens the service life of industrial equipment and, in severe cases, can even lead to information security issues. Device-level material corrosion monitoring is a key technology for analyzing the causes of device corrosion failure, determining the state of material corrosion failure, and predicting the lifespan of devices subjected to corrosion failure. Traditional corrosion monitoring technologies utilize mechanical structural sensors, which are incapable of device-level material corrosion monitoring. Furthermore, they are bulky, inaccurate, expensive, and difficult to mass-produce, making them incapable of large-scale monitoring of electronic device corrosion failure. With the continuous advancement of science and technology and the continuous development of society in recent years, MEMS (microelectromechanical systems) have experienced significant development, and accordingly, MEMS sensors have also seen significant development. They have been widely used in automotive, security, biomedical, power, smart buildings, forest fire prevention, smartphones, and the Internet of Things. However, MEMS sensors suitable for material corrosion have remained underdeveloped due to technical limitations. Therefore, this application utilizes micromechanical manufacturing processes to achieve device-level material corrosion monitoring, which is crucial for the development of material corrosion big data technology and MEMS sensors. Summary of the Invention

[0003] The purpose of this application is to provide a silicon-metal composite MEMS material atmospheric corrosion sensor, its preparation method and material atmospheric corrosion detection equipment, so as to solve the problems of poor stability, low repeatability and difficulty in mass production of existing mechanical atmospheric corrosion sensors.

[0004] To achieve the above objectives, this application adopts the following technical solutions: A silicon-metal composite MEMS material atmospheric corrosion sensor, comprising an anode and cathode module and a cavity structure module; The anode and cathode modules include a first substrate and a metal anode and a metal cathode disposed on the surface of the first substrate, each of which is independent; The cavity structure module includes a second substrate, the second substrate is provided with a recessed portion and a through hole for communicating with the test environment atmosphere, the recessed portion extends from a first side of the second substrate to an opposite second side, and the through hole extends from a surface of the second side to a bottom of the recessed portion; The surface of the second side abuts against the surface of the first substrate, and the metal cathode and the metal anode are arranged in the recessed portion; The material of the metal anode is the metal material to be tested, and the material of the metal cathode is coupled with the metal material to be tested; The distance between the metal anode and the metal cathode is 10-100 μm.

[0005] If the spacing is too small, a short circuit is likely to occur when conductive corrosion products or conductive particles in the air are deposited. If the spacing is too large, the sensor will become insensitive to changes in environmental corrosion, greatly reducing the sensitivity of the sensor. Taking all factors into consideration, the spacing between the metal anode and the metal cathode should be controlled between 10 microns and 100 microns.

[0006] Preferably, the first substrate and the second substrate are each independently made of silicon wafer or glass.

[0007] Preferably, the first substrate is a silicon wafer, the second substrate is glass, the metal material to be tested is stainless steel, and the material of the metal cathode is copper.

[0008] The present application also provides a method for preparing the silicon-metal composite MEMS material atmospheric corrosion sensor, comprising: Bonding the sheet-shaped metal material to be tested to the first substrate to obtain a substrate-metal composite sheet; Disposing a photoresist on the surface of the substrate-metal composite sheet, then performing exposure, development, and fixing using a mask having a metal anode pattern to form a metal anode target pattern; etching using the metal anode target pattern until the first substrate is revealed, and then removing residual photoresist to obtain a first composite sheet; A photoresist is provided on the side of the first composite sheet having the metal anode, and a mask having a metal cathode pattern is used to perform exposure, development, and fixing to form a metal cathode target pattern to obtain a second composite sheet; a cathode material is sputtered on the second composite sheet using a sputtering method, and then the photoresist and cathode material remaining on the second composite sheet are removed to obtain the anode and cathode modules; Disposing a photoresist on the first side of the second substrate, then performing exposure, development, and fixing using a mask having a pattern of the recessed portion to form a recessed portion target pattern; performing etching using the recessed portion target pattern until the recessed portion is formed; removing residual photoresist, then disposing a photoresist on the second side, then performing exposure, development, and fixing using a mask having a pattern of the through hole to form a through hole target pattern; performing etching using the through hole target pattern until the through hole is formed, and removing residual photoresist to obtain the cavity structure module; The metal anode and the metal cathode of the anode and cathode modules are arranged in the recessed portion of the cavity structure module, and then the surface of the second side of the first substrate is connected to the surface of the first substrate.

[0009] Preferably, the bonding is performed using a polydimethylsiloxane two-component adhesive.

[0010] Preferably, when etching is performed using the metal anode target pattern, the etchant comprises: HCl 2.7-5.4mol / L, hydrogen peroxide 4.4-7.4mol / L, corrosion inhibitor 1-10g / L, dispersant 20-50g / L, hydrogen peroxide stabilizer 5-10g / L.

[0011] Preferably, the connection includes: Performing chemical cleaning and activation treatment on the surface of the second side and the surface of the first substrate by a wet chemical treatment method; The first substrate is connected to the positive pole of the power supply, the second substrate is connected to the negative pole of the power supply, the temperature is raised to 300-500°C, and a bias voltage of more than 500V is applied to allow the first substrate and the second substrate to be bonded by the generated electrostatic force.

[0012] The present application also provides a material atmospheric corrosion detection device, including the silicon-metal composite MEMS material atmospheric corrosion sensor.

[0013] Preferably, the material atmospheric corrosion detection equipment further comprises a signal processing module electrically connected to the silicon-metal composite MEMS material atmospheric corrosion sensor, and the signal processing module comprises an ASIC chip with micro-current and micro-voltage detection capabilities.

[0014] Preferably, the material atmospheric corrosion detection equipment further comprises a lead frame structure capable of carrying the silicon-metal composite MEMS material atmospheric corrosion sensor and the ASIC chip.

[0015] Compared with the prior art, the advantages of this application include: The silicon-metal composite MEMS material atmospheric corrosion sensor provided in this application optimizes the performance of the material corrosion sensor by setting a material corrosion electrochemical sensitive material on a non-metallic substrate, integrating the material corrosion sensitive element and the electrical quantity detection module into one, and can greatly improve the sensitivity, reliability and consistency of the material corrosion sensor.

[0016] This application uses a silicon-metal composite MEMS atmospheric corrosion sensor manufacturing process. Silicon and metal materials are bonded together, and then a working electrode (anode) for corrosion monitoring is etched onto the metal. A counter electrode and a reference electrode (cathode) are then sputtered onto the silicon substrate. This application addresses the differences in composition and structure between traditional sputtered metal sensors and machined sensors, while also addressing the challenges of small size, uniformity, high stability, and mass production. This technology can promote the wider application of MEMS atmospheric corrosion sensors in various high-precision online atmospheric corrosion monitoring scenarios.

[0017] The material atmospheric corrosion detection equipment provided in this application includes two major parts: micromachining technology and microelectronics technology. One part converts material corrosion into signal changes such as capacitance, resistance, and current through a MEMS chip, and the other part converts signal changes such as capacitance, resistance, and inductance into electrical signals through an ASIC chip, thereby realizing the function of a MEMS corrosion sensor - converting material corrosion signals into electrical signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope of the present application.

[0019] Figure 1 Schematic diagram of bonding silicon wafer and metal sheet; Figure 2 Schematic diagram of MEMS sensor preparation; Figure 3 Schematic diagram of the cavity structure; Figure 4 This is the main view of the MEMS sensor; Figure 5 This is a top view of the MEMS sensor; Figure 6 A three-dimensional view of the MEMS sensor.

[0020] Reference numerals: 1-metal anode, 2-silicon wafer, 3-PDMS adhesive, 4-metal cathode, 5-glass sheet, 6-through hole. DETAILED DESCRIPTION

[0021] The embodiments of the present application will be described in detail below in conjunction with specific examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, the conditions are carried out according to conventional conditions or manufacturer recommendations. The reagents or instruments used are not specified by the manufacturer and are conventional products that can be purchased commercially.

[0022] Example 1 This embodiment provides a silicon-metal composite MEMS material atmospheric corrosion sensor, including an anode and cathode module and a cavity structure module; the anode and cathode module include a silicon wafer and a metal anode and a metal cathode respectively arranged on the surface of the silicon wafer; the cavity structure module includes a glass wafer, the glass wafer is provided with a recessed portion and a through hole for communicating with the test environment atmosphere, the recessed portion extends from a first side of the glass wafer to an opposite second side, and the through hole extends from the surface of the second side to the bottom of the recessed portion; the surface of the second side is bonded to the surface of the silicon wafer, and the metal cathode and the metal anode are arranged in the recessed portion.

[0023] The preparation method is as follows: (1) Preparation of metal anode 1 5.1 Reference Figure 1 , Figure 1 Schematic diagram of bonding silicon wafer and metal sheet, as shown in Figure 1 As shown, silicon wafer 2, specifically 4-inch (φ100.84mm) wafer is selected as the substrate material, 316L stainless steel is selected as the metal anode material, 316L stainless steel is cut into φ100.84mm×300μm size, the stainless steel surface is polished to 5000# step by step with SiC sandpaper, and polished to 1μm particle size step by step with Al2O3 polishing paste, and cleaned with deionized water and high-purity alcohol, and blown dry for use.

[0024] 5.2 Use PDMS adhesive 3 (polydimethylsiloxane two-component adhesive) to bond silicon wafer 2 and 316L stainless steel. First, thoroughly mix liquid component A (PDMS prepolymer) and component B (curing agent) in a weight ratio of 10:1 to form a medium-viscosity mixture. Then, evenly apply it to the surfaces of the silicon wafer and 316L stainless steel, concentrically bond the two, and place them on a heating table. Adjust the heating table temperature to 100 degrees Celsius and cure for 35 minutes to fully cure the PDMS adhesive.

[0025] 5.3 Use 30% hydrochloric acid and ultrapure water in a 1:1 volume ratio to prepare an acidic cleaning solution to remove oxides from the surface of the 316L stainless steel. Then use a large amount of deionized water to rinse the silicon-316L stainless steel sheet and use a high-speed spin dryer to dry the silicon-316L stainless steel. The spin drying process time is 300 seconds.

[0026] 5.4 Reference Figure 2 SU-8 semiconductor UV photoresist is used to coat the silicon wafer 2. The SU-8 photoresist component is evenly spin-coated on the substrate at a speed of 1000 r / min. The spin coating thickness is controlled at 120 microns. The silicon wafer is heated at 80 to 120°C for 120 seconds using a uniform heating plate to fully dry it. After that, it is transferred to the photolithography machine and the mask of the anode metal material is loaded on the photolithography machine for photolithography development. The UV radiation dose is 200 mJ / cm 2 Take a 10-second exposure.

[0027] 5.5 Use SU-8 developer to fully develop until the anode metal material pattern is clearly and completely presented.

[0028] After 5.6, the stainless steel is etched with a stainless steel etching solution. The recommended components of the stainless steel etching solution are FeCl3800g / L, HCl 100 mL / L, HF 100 mL / L, H3PO48g / L, and CuSO420g / L. The etching depth is equal to the thickness of the stainless steel.

[0029] 5.7 After sufficient etching, first, the surface of the silicon-316L stainless steel is thoroughly cleaned with ultrapure water; then the photoresist is stripped and cleaned using SPM cleaning technology.

[0030] (2) Preparation of metal cathode 4 5.8 Reference Figure 2 Repeat step 5.4, except that the mask of the cathode metal material is loaded onto the photolithography machine for photolithography development; 5.9 Repeat step 5.5, except that the cathode metal material pattern is clearly and completely presented; 5.10 The cathode electrode required for the electrochemical measurement of material corrosion was formed by magnetron sputtering. In this embodiment, a Cu target with a metal content of 99.999% was used, with an operating pressure of 0.5 Pa, a target voltage of 450 V, and a target current density of 20 mA / cm 2 , the deposition rate is about 1.5 nm / min; 5.11 Use SPM cleaning technology to strip the photoresist on the anode and cathode metals and clean the residual metal.

[0031] The distance between the metal anode and the metal cathode is 50 μm.

[0032] (3) Preparation of cavity structure 5.12 Reference Figure 3A 4-inch (φ100.84 mm) glass sheet 5 was selected as the cavity structure material, and the surface was cleaned with deionized water. Subsequently, the glass sheet was cleaned with a cleaning solution consisting of 25% hydrogen peroxide, 25% ammonia water, and pure water in a volume ratio of 1:1:20 for approximately 260 seconds. The cleaning was then continued for 250 seconds with a cleaning solution consisting of 30% hydrochloric acid, 25% hydrogen peroxide, and pure water in a volume ratio of 1:1:20. The silicon wafer was then rinsed with a large amount of deionized water and dried using a high-speed spin dryer for 300 seconds. 5.13 Repeat step 5.4, except that the mask of the cavity structure is loaded onto the photolithography machine for photolithography development; 5.14 Repeat step 5.5, but make the cavity structure pattern clear and complete; 5.15 Etching the glass sheet using a deep silicon etching method to remove the exposed substrate area and etching a cavity downward in the exposed substrate area; 5.16 Use SPM cleaning technology to strip and clean the photoresist; 5.17 Repeat the glass cleaning process in step 5.12; 5.18 Repeat step 5.4, except that photoresist is applied to the reverse side of the glass sheet and the mask with the cavity structure is loaded onto a photolithography machine for photolithography development; 5.19 Repeat steps 5.15 to 5.17, except that a through hole 6 is etched from the back of the glass sheet so that atmospheric environmental factors can pass through the glass sheet and enter the sensor surface.

[0033] (4) Silicon-glass anodic bonding 5.20 First, the silicon-316L stainless steel sensor structure and cavity structure were chemically cleaned and activated using a wet chemical treatment method. The wet chemical treatment solution was RCA1 (NH4OH:H2O2:H2O = 1:1:5) solution to clean the silicon wafer and remove organic contamination on the silicon surface. RCA2 (HCl:H2O2:H2O = 1:1:6) solution was used for surface activation to remove ionic and metallic contamination at the silicon interface and increase the electrostatic tension at the silicon-glass interface. 5.21 Connect silicon wafer 2 to the positive pole of the power supply and glass wafer 5 to the negative pole of the power supply. Raise the temperature to 300-500°C and apply a bias voltage of 500V or more to allow the electrostatic force generated by silicon wafer 2 and glass wafer 5 to bond.

[0034] The resulting MEMS sensor is Figure 4 、 Figure 5 and Figure 6 shown.

[0035] In other embodiments, the anode and cathode modules and the cavity structure module may be connected by coating a titanium adhesive layer on the surface of the cavity structure or providing solder.

[0036] This embodiment also provides a material atmospheric corrosion detection device, the specific preparation method is as follows: (5) Wire bonding 5.22 The MEMS sensor obtained above was wire-bonded to the nickel-palladium-silver-gold frame. Before bonding, the lead frame and MEMS corrosion sensor were plasma cleaned using a plasma cleaning device. The cleaning process was as follows: argon was introduced into the copper of the device, and the sample was placed in the plasma zone. The pressure was controlled at 200 Pa and the power density was 8 W / cm. 2 The cleaning time is 10 minutes. Then, the MEMS chip and the nickel-palladium-silver-gold frame are wire-bonded using a copper bonding process.

[0037] The atmospheric corrosion detection device also includes a signal processing module, a specialized ASIC chip capable of detecting microcurrents and microvoltages. In this example, the MAX4080SASA+T high-precision current detection amplifier IC is used. This module detects the current and voltage signals generated by atmospheric corrosion-sensitive components and converts them into electrical signals signaling the material's corrosion rate. This ASIC chip is supported on the nickel-palladium-silver-gold frame and electrically connected to the MEMS corrosion sensor.

[0038] Finally, the MEMS material corrosion sensor and ASIC signal processing module are encapsulated with plastic packaging material.

[0039] The present application provides a silicon-metal composite MEMS material atmospheric corrosion sensor and a preparation method thereof. By etching an anode electrode of a metal material having a consistent structural material and combining it with a cathode electrode prepared by sputtering, a MEMS corrosion sensor with a planar structure is formed. Combined with an ASIC microcurrent processing chip, the atmospheric corrosion of the metal material and the detection of the tiny corrosion current formed between the anode and the cathode are realized. The corrosion signal is detected through the ASIC amplification circuit and digital-to-analog conversion. Thus, a sensor preparation technology for materials consistent with the structural composition and organizational structure of bulk metal is realized, eliminating the problem of inconsistent material organizational structure caused by the use of sputtered metal, and the resulting difference between the actual corrosion mechanism and the corrosion mechanism of the metal to be measured. At the same time, the present application realizes the batch preparation of microsensors through MEMS technology, which greatly improves the consistency and linearity of material corrosion sensors.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A silicon-metal composite MEMS material atmospheric corrosion sensor, characterized in that: It includes anode and cathode modules and a cavity structure module; The cathode and anode modules include a first substrate and a metal anode and a metal cathode which are independently arranged on the surface of the first substrate; The cavity structure module includes a second substrate, the second substrate is provided with a recessed portion and a through hole for communicating with the test environment atmosphere, the recessed portion extends from a first side of the second substrate to an opposite second side, and the through hole extends from a surface of the second side to a bottom of the recessed portion; The surface of the second side abuts against the surface of the first substrate, and the metal cathode and the metal anode are arranged in the recessed portion; The material of the metal anode is the metal material to be tested, and the material of the metal cathode is coupled with the metal material to be tested; The distance between the metal anode and the metal cathode is 10-100 μm.

2. The silicon-metal composite MEMS atmospheric corrosion sensor according to claim 1, characterized in that: The first substrate and the second substrate are independently made of silicon wafer or glass.

3. The silicon-metal composite MEMS material atmospheric corrosion sensor according to claim 1 or 2, characterized in that: The first substrate is a silicon wafer, the second substrate is glass, the metal material to be tested is stainless steel, and the material of the metal cathode is copper.

4. A method for preparing a silicon-metal composite MEMS atmospheric corrosion sensor according to any one of claims 1 to 3, characterized in that: include: Bonding the sheet-shaped metal material to be tested to the first substrate to obtain a substrate-metal composite sheet; Disposing a photoresist on the surface of the substrate-metal composite sheet, and then using a mask having a metal anode pattern to perform exposure, development, and fixing to form a metal anode target pattern; Etching is performed using the metal anode target pattern until the first substrate is revealed, and then the residual photoresist is removed to obtain a first composite sheet; A photoresist is disposed on the side of the first composite sheet having the metal anode, and a mask having a metal cathode pattern is used for exposure, development, and fixing to form a metal cathode target pattern to obtain a second composite sheet; a cathode material is sputtered on the second composite sheet by a sputtering method, and then the photoresist and residual cathode material remaining on the second composite sheet are removed to obtain the anode and cathode modules; Disposing a photoresist on the first side of the second substrate, and then performing exposure, development, and fixing using a mask having the pattern of the recessed portion to form a target pattern of the recessed portion; Etching using the recessed portion target pattern until the recessed portion is formed; Removing the residual photoresist, then disposing photoresist on the second side, and then using a mask having the pattern of the through hole to perform exposure, development, and fixing to form a through hole target pattern; Etching is performed using the through hole target pattern until the through hole is formed, and the residual photoresist is removed to obtain the cavity structure module; The metal anode and the metal cathode of the anode and cathode modules are arranged in the recessed portion of the cavity structure module, and then the surface of the second side of the first substrate is connected to the surface of the first substrate.

5. The method for preparing the silicon-metal composite MEMS atmospheric corrosion sensor according to claim 4, characterized in that: The bonding is performed using a polydimethylsiloxane two-component adhesive.

6. The method for preparing the silicon-metal composite MEMS atmospheric corrosion sensor according to claim 4, characterized in that: When etching is performed using the metal anode target pattern, the etchant includes: HCl 2.7-5.4mol / L, hydrogen peroxide 4.4-7.4mol / L, corrosion inhibitor 1-10g / L, dispersant 20-50g / L, hydrogen peroxide stabilizer 5-10g / L.

7. The method for preparing the silicon-metal composite MEMS atmospheric corrosion sensor according to any one of claims 4 to 6, characterized in that: The connection includes: Using a wet chemical treatment method to chemically clean and activate the surface of the second side and the surface of the first substrate; The first substrate is connected to the positive pole of the power supply, the second substrate is connected to the negative pole of the power supply, the temperature is raised to 300-500° C., and a bias voltage of more than 500V is applied, so that the first substrate and the second substrate are bonded by the generated electrostatic force.

8. A material atmospheric corrosion detection device, characterized in that: The atmospheric corrosion sensor comprising the silicon-metal composite MEMS material as claimed in any one of claims 1 to 3.

9. The material atmospheric corrosion detection device according to claim 8, characterized in that: It also includes a signal processing module electrically connected to the silicon-metal composite MEMS material atmospheric corrosion sensor, and the signal processing module includes an ASIC chip with micro-current and micro-voltage detection capabilities.

10. The material atmospheric corrosion detection equipment according to claim 9, characterized in that: It also includes a lead frame structure capable of carrying the silicon-metal composite MEMS material atmospheric corrosion sensor and the ASIC chip.

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