Salt spray environment parameter detection micro-nano sensor and preparation and measurement method thereof

Abstract

The invention provides a salt spray environment parameter detection micro-nano sensor and a preparation and measurement method thereof, the salt spray environment parameter detection micro-nano sensor comprises a silicon substrate, the upper surface and the lower surface of the silicon substrate are respectively provided with a SiO2 insulation layer and a first Si3N4 film; the first Pt resistor is arranged on the upper surface of the SiO2 insulating layer, a second Si3N4 thin film is deposited on the upper surface of the first Pt resistor, and first Au interdigital electrodes are arranged on the two sides, in the length direction of the silicon substrate, of the first Pt resistor; the second Pt resistor is arranged on the lower surface of the first Si3N4 film; the third Pt resistor is arranged on the upper surface of the adhesion layer on the SiO2 insulating layer, a third Si3N4 thin film is deposited on the surface of the third Pt resistor, a patterned second Au interdigital electrode is arranged on the upper surface of the third Si3N4 thin film, and a PI thin film is deposited on the upper surface of the second Au interdigital electrode. The device has the beneficial effects that the wetting time is shortened through the'hollow-window-flower-like 'interdigital microelectrodes, high-precision measurement of the temperature and heat exchange of the sensor body and salt mist gas can be realized, the influence of temperature and humidity on conductivity detection is eliminated through data compensation, the desorption process is accelerated, and wet stagnation is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of sensors, and in particular to a salt spray environment parameter detection micro-nano sensor and a preparation and measurement method thereof. Background Art

[0002] Corrosion is one of the serious problems that affect the health of aviation structures. It is a destructive erosion process caused by chemical or electrochemical reactions between metals and the surrounding environment. According to relevant statistics, the economic losses caused by corrosion each year far exceed the sum of natural disasters and other accidents. The implementation of effective corrosion protection measures can avoid 25%-40% of corrosion losses. Therefore, it is necessary and urgent to carry out online monitoring of the corrosion status and corrosion environmental factors of flight equipment. The atmosphere and salt spray environmental parameters are the main environmental factors, and the correctness and accuracy of their detection are directly related to the navigation safety of flight equipment.

[0003] Typical salt spray environmental parameters include temperature, humidity, chloride ion concentration, salt concentration and other indicators. At present, domestic enterprises started late in the research of salt spray environmental parameter detection, and there are still many problems with the products. For example, the built-in reference electrode of the chloride ion detection unit has a limited life, and long-term continuous monitoring of the sensor cannot be achieved. It has not yet been widely promoted and applied. The wetting time is one of the negative indicators of salt spray environmental parameters. At present, the products that measure this parameter mostly use ordinary interdigital electrodes, but there are problems such as high humidity requirements, long reaction time and weak anti-interference.

[0004] The salt spray environment is complex and changeable, with many test interference factors. There is also cross-interference between the multiple sensing units of the sensor. For example, temperature and humidity interfere with the formation of the liquid film in the conductivity sensing area, directly causing the conductivity test to shift. The difference between the sensor body temperature and the ambient temperature directly affects the chloride ion mass transfer between the liquid film and the salt spray gas, which will also cause the conductivity test to shift. In addition, the sensor is carried on an aircraft and is used, which requires a short response time for the sensor. Otherwise, excessive sensing hysteresis will lead to deviations in the corrosion status assessment.

[0005] It can be seen from this that the measurement accuracy of the current salt spray environmental parameter sensors is not high, the detected conductivity is greatly affected by temperature and humidity, and the wetness time is long and the humidity stagnation is serious. Summary of the invention

[0006] The problem to be solved by the present invention is to provide a salt fog environmental parameter detection micro-nano sensor and a preparation and measurement method thereof, which can improve the measurement accuracy of salt fog environmental parameters, reduce the wetting time, reduce the influence of temperature and humidity on conductivity, and reduce hysteresis.

[0007] In order to solve the above problems, the present invention provides a salt spray environment parameter detection micro-nano sensor, comprising:

[0008] A silicon substrate, wherein a SiO2 insulating layer is provided on the upper surface of the silicon substrate, a first Si3N4 film is deposited on the lower surface of the silicon substrate, and an adhesion layer is provided on the surfaces of the SiO2 insulating layer and the first Si3N4 film;

[0009] A first Pt resistor is disposed on the upper surface of the adhesion layer on the SiO2 insulating layer, a second Si3N4 film is deposited on the upper surface of the first Pt resistor, and patterned first Au interdigital electrodes in a hollow window-like shape are disposed on both sides of the first Pt resistor along the length direction of the silicon substrate;

[0010] A second Pt resistor is disposed on the lower surface of the adhesion layer on the first Si3N4 film;

[0011] a third Pt resistor, arranged on the upper surface of the adhesion layer on the SiO2 insulating layer and located on one side of the first Pt resistor along the length direction of the silicon substrate, a third Si3N4 film is deposited on the surface of the third Pt resistor, a patterned second Au interdigital electrode is arranged on the upper surface of the third Si3N4 film, and a PI film is deposited on the upper surface of the second Au interdigital electrode;

[0012] The first Au interdigital electrode comprises:

[0013] Two rectangular pads, one side of the two rectangular pads along the width direction of the silicon substrate is respectively connected to one end of a long electrode connector, a plurality of first long metal electrodes and second long metal electrodes are arranged alternately and spaced along their own length direction between the two long electrode connectors, one end of each of the first long metal electrodes is fixedly connected to one of the long electrode connectors, and a gap is provided between the other end of each of the first long metal electrodes and the other long electrode connector, one end of each of the second long metal electrodes is fixedly connected to the other long electrode connector, and a gap is provided between the other end of each of the second long metal electrodes and one of the long electrode connectors, and a plurality of first T-shaped metal electrodes and second T-shaped metal electrodes are arranged alternately and spaced along their own length direction between adjacent first long metal electrodes and second long metal electrodes, a protrusion of each of the first T-shaped metal electrodes faces one of the long electrode connectors, and a protrusion of each of the second T-shaped metal electrodes faces the other long electrode connector.

[0014] Preferably, the first Pt resistor and the second Pt resistor are serpentine Pt resistors with the same parameters, and the position of the first Pt resistor on the SiO2 insulating layer and the position of the second Pt resistor on the first Si3N4 film overlap along the height direction of the silicon substrate.

[0015] Preferably, the third Pt resistor is a circular Pt resistor low-power heater.

[0016] The present invention also provides a method for preparing a salt spray environment parameter detection micro-nano sensor, which is applied to the above-mentioned salt spray environment parameter detection micro-nano sensor, and comprises the following steps:

[0017] Step S1, obtaining a silicon wafer with a surface having a (100) crystal orientation after removing surface stains and an oxide layer as the silicon substrate;

[0018] Step S2, preparing the SiO2 insulating layer on the upper surface of the silicon substrate, and preparing the first Pt resistor and the third Pt resistor, which are patterned and distributed along the length direction of the silicon substrate, on the upper surface of the SiO2 insulating layer;

[0019] Step S3, depositing a Si3N4 film on the surface of the first Pt resistor and the third Pt resistor, and etching to obtain the second Si3N4 film and the third Si3N4 film;

[0020] Step S4, preparing the first Au interdigital electrodes in a pattern on both sides of the first Pt resistor along the length direction of the silicon substrate, and preparing the second Au interdigital electrodes in a pattern on the upper surface of the third Si3N4 film;

[0021] Step S5, depositing the first Si3N4 film on the lower surface of the silicon substrate, and scribing the first Si3N4 film at both ends along the length direction of the silicon substrate;

[0022] Step S6, preparing the patterned second Pt resistor on the lower surface of the first Si3N4 film, and preparing the PI film on the upper surface of the second Au interdigital electrode by spin coating, followed by wire bonding and packaging to obtain the salt spray environment parameter detection micro-nano sensor.

[0023] Preferably, in step S2, the silicon substrate is first dry-oxidized for 50 minutes at 1100°C, and then wet-oxidized for 450 minutes to obtain a uniform SiO2 insulating layer with a double-sided thickness of 2 um, and the SiO2 insulating layer on the lower surface of the silicon substrate is removed by wet etching with a BOE solution.

[0024] Preferably, in step S2, the upper surface of the SiO2 insulating layer is sequentially coated with glue, pre-baked, photolithographically coated, and developed, and a patterned first photoresist mask is prepared by post-baking after development, and then a layer of Cr is sputtered on the upper surface of the first photoresist mask as the adhesion layer by a magnetron sputtering process, and then a 50 / 200nm Pt metal layer is sputtered, and based on the photolithography pattern on the first photoresist mask, the Pt metal layer is etched by a lift-off process to obtain the first Pt resistor and the third Pt resistor, respectively.

[0025] Preferably, in step S3, a layer of the Si3N4 film with a thickness of 700 nm is deposited on the surface of the first Pt resistor and the third Pt resistor by a plasma chemical vapor deposition process, and the upper surface of the Si3N4 film is sequentially coated with glue, pre-baked, photolithographically, and developed, and a patterned second photoresist mask is prepared by post-baking after development, and then based on the photolithographic pattern on the second photoresist mask, the Si3N4 film is etched by a reactive ion etching process to obtain the second Si3N4 film and the third Si3N4 film.

[0026] Preferably, in step S4, a layer of Cr is sputtered as the adhesion layer on both sides of the first Pt resistor along the length direction of the silicon substrate and on the upper surface of the third Si3N4 film using a magnetron sputtering process, and then a layer of 30 / 300nm Au metal layer is sputtered, and then the upper surface of the Au metal layer is coated with glue, pre-baked, photolithographic, and developed in sequence, and a patterned third photoresist mask is prepared by post-baking after development, and based on the photolithography pattern on the third photoresist mask, the Au metal layer is etched using an IBE process to obtain the patterned first Au interdigital electrode and the second Au interdigital electrode.

[0027] Preferably, in the step S5, a plasma chemical vapor deposition process is used to deposit the first Si3N4 film with a thickness of 2 um on the lower surface of the silicon substrate.

[0028] The present invention also provides a salt spray environment parameter detection micro-nano sensor measurement method, which is applied to the above-mentioned salt spray environment parameter detection micro-nano sensor, and comprises the following steps:

[0029] Step A1, placing the salt spray environment parameter detection micro-nano sensor and the humidity thermometer in a salt spray test chamber to measure the temperature and humidity in the salt spray test chamber;

[0030] Step A2, keeping the temperature in the salt spray test box unchanged, continuously spraying a neutral salt spray solution to the salt spray environment parameter detection micro-nano sensor, and monitoring the resistance value change and current temperature of the first Pt resistor and the second Pt resistor, the capacitance change and current humidity of the second Au interdigital electrode, and the current and voltage changes between the two first Au interdigital electrodes in real time, and adding them to the monitoring data;

[0031] Step A3, maintaining the temperature in the salt spray test box constant and adjusting the humidity or maintaining the humidity in the salt spray test box constant and adjusting the temperature, and obtaining the relationship between the temperature and humidity and the change of conductivity and the surface liquid film wetting time according to the monitoring data;

[0032] Step A4: Based on the relationship, the temperature and humidity are calibrated and the conductivity is calculated using the formula σ=K / R S As well as the relationship between capacitance and dielectric constant C=nεlh / Ws+nε / 2, the corresponding temperature and humidity, wetting time and conductivity parameters are obtained.

[0033] The present invention has the following beneficial effects: the present invention innovatively designs a "hollow window grille-shaped" first Au interdigital electrode to achieve a small gap between the sensitive electrode and the proton membrane and a large contact area between the liquid membrane and the sensitive electrode, so as to reduce the wetting time; based on the lift-off process, temperature electrodes with the same parameters, namely, a first Pt resistor and a second Pt resistor, are prepared on both sides of different substrates of a silicon substrate, and the regions of the first Pt resistor and the second Pt resistor overlap in the height direction, so as to achieve high-precision measurement of the sensor body, the temperature of the salt spray gas and the heat exchange, and data compensation for the conductivity test; based on the MEMS technology, the temperature, humidity and conductivity detection components are prepared in the same micro-area, and the influence of temperature and humidity on the conductivity detection is reduced through data compensation; and a low-power heater, namely, a second Pt resistor, is designed and provided at the bottom of the humidity detection component, so as to accelerate the desorption process and reduce hysteresis. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the sensor structure decomposition of the present invention;

[0035] Figure 2 A top view of the first Au interdigital electrode in the shape of a hollow window grille of the present invention;

[0036] Figure 3 is a flow chart of the steps of the preparation method of the present invention;

[0037] Figure 4 is a process flow chart of the preparation method of the present invention;

[0038] Figure 5 is a flow chart of the steps of the measuring method of the present invention;

[0039] Explanation of the reference numerals in the accompanying drawings: 1. Silicon substrate; 2. SiO2 insulating layer; 3. First Si3N4 film; 4. First Pt resistor; 5. Second Si3N4 film; 6. First Au interdigital electrode; 61. Rectangular pad; 62. Long electrode connector; 63. First long metal electrode; 64. Second long metal electrode; 65. First T-shaped metal electrode; 66. Second T-shaped metal electrode; 67. Protrusion; 7. Second Pt resistor; 8. Third Pt resistor; 9. Third Si3N4 film; 10. Second Au interdigital electrode; 11. PI film; 12. Si3N4 film. DETAILED DESCRIPTION

[0040] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0041] In a preferred embodiment of the present invention, based on the above problems existing in the prior art, a salt spray environment parameter detection micro-nano sensor is provided. Figure 1 and Figure 2 As shown, including:

[0042] A silicon substrate 1, wherein a SiO2 insulating layer 2 is provided on the upper surface of the silicon substrate 1, a first Si3N4 film 3 is deposited on the lower surface of the silicon substrate 1, and an adhesion layer is provided on the surfaces of the SiO2 insulating layer 2 and the first Si3N4 film 3;

[0043] A first Pt resistor 4 is disposed on the upper surface of the adhesion layer on the SiO2 insulating layer 2, a second Si3N4 film 5 is deposited on the upper surface of the first Pt resistor 4, and patterned first Au interdigital electrodes 6 in a hollow window shape are disposed on both sides of the first Pt resistor 4 along the length direction of the silicon substrate 1;

[0044] A second Pt resistor 7 is disposed on the lower surface of the adhesion layer on the first Si3N4 film 3;

[0045] The third Pt resistor 8 is arranged on the upper surface of the adhesion layer on the SiO2 insulating layer 2 and is located on one side of the first Pt resistor 4 along the length direction of the silicon substrate 1. A third Si3N4 film 9 is deposited on the surface of the third Pt resistor 8. A patterned second Au interdigital electrode 10 is arranged on the upper surface of the third Si3N4 film 9. A PI film 11 is deposited on the upper surface of the second Au interdigital electrode 10.

[0046] The first Au interdigital electrode 6 comprises:

[0047] Two rectangular pads 61, one side of the two rectangular pads 61 along the width direction of the silicon substrate 1 is respectively connected to one end of a long electrode connector 62, and a plurality of first long metal electrodes 63 and second long metal electrodes 64 are arranged alternately and spaced along the length direction thereof between the two long electrode connectors 62, one end of each first long metal electrode 63 is fixedly connected to one of the long electrode connectors 62, and a gap is formed between the other end of each first long metal electrode 63 and the other long electrode connector 62, and one end of each second long metal electrode 64 is fixedly connected to the other end of the long electrode connector 62. It is fixedly connected to another long electrode connector 62, and there is a gap between the other end of each second long metal electrode 64 and one of the long electrode connectors 62, and a plurality of first T-shaped metal electrodes 65 and second T-shaped metal electrodes 66 are arranged alternately and spaced along their own length direction between adjacent first long metal electrodes 63 and second long metal electrodes 64, and the protrusion 67 of each first T-shaped metal electrode 65 faces one of the long electrode connectors 62, and the protrusion 67 of each second T-shaped metal electrode 66 faces the other long electrode connector 62.

[0048] Specifically, in this embodiment, the first T-shaped metal electrode 65 and the second T-shaped metal electrode 66 are both composed of a protrusion 67 and a fixing member perpendicular to the protrusion 67. Taking the first T-shaped metal electrode 65 and the second T-shaped metal electrode 66 between any adjacent first long metal electrode 63 and second long metal electrode 64 as an example, the first long metal electrode 63 is fixed to the long electrode connecting member 62 on the right, and the second long metal electrode 64 is fixed to the long electrode connecting member 62 on the left, and the first long metal electrode The electrode 63 is closer to the rectangular pad 61 than the second long metal electrode 64. The first T-shaped metal electrode 65 is located on the far left, and the protrusion 67 of the first T-shaped metal electrode 65 is facing the long electrode connector 62 on the right. The second T-shaped metal electrode 66 is located on the far right, and the protrusion 67 of the second T-shaped metal electrode 66 is facing the long electrode connector 62 on the left. The protrusion 67 of the first T-shaped metal electrode 65 is closer to the rectangular pad 61 than the protrusion 67 of the second T-shaped metal electrode 66.

[0049] In a preferred embodiment of the present invention, the first Pt resistor 4 and the second Pt resistor 7 are serpentine Pt resistors with the same parameters, and the position of the first Pt resistor 4 on the SiO2 insulating layer 2 and the position of the second Pt resistor 7 on the first Si3N4 film 3 overlap along the height direction of the silicon substrate 1.

[0050] In a preferred embodiment of the present invention, the third Pt resistor 8 is a circular Pt resistor low-power heater.

[0051] Specifically, in this embodiment, the present invention is based on MEMS technology, with silicon or silicon oxide or silicon nitride as the substrate, and serpentine Pt resistors with the same parameters are used at corresponding positions on the front and back surfaces to detect temperature; an Au interdigital electrode system is prepared by magnetron sputtering technology and ion beam etching technology to detect humidity and conductivity.

[0052] Preferably, the salt spray environment parameter detection micro-nano sensor proposed in the present invention has the following significant advantages: 1) The wetting time is measured by the "hollow window grille-shaped" first Au interdigital electrode 6, so as to realize the small gap between the sensitive electrode and the proton membrane and the large contact area between the liquid membrane and the sensitive electrode; 2) The solid-gas interface heat exchange measurement and high-precision measurement, as well as data compensation are realized by dual temperature detection; 3) The temperature, humidity and conductivity sensors are integrated into the same micro-area based on MEMS technology to realize miniaturization, low cost and batch preparation; 4) With the aid of a "circular" Pt resistor low-power heater, the desorption process is accelerated and hysteresis is reduced. The present invention realizes the batch preparation of low-cost, integrated micro-nano sensors for salt spray environment parameter detection, and combines low-power consumption, high-precision signal acquisition circuits and data fusion algorithms to provide core sensors for corrosion status monitoring and prediction of flight equipment.

[0053] Preferably, the salt spray environment parameter detection micro-nano sensor proposed in the present invention has higher measurement accuracy and lower cost while ensuring multi-parameter integration, and has great practical application value.

[0054] The present invention also provides a method for preparing a salt spray environment parameter detection micro-nano sensor, which is applied to the above-mentioned salt spray environment parameter detection micro-nano sensor, such as Figure 3 and Figure 4 As shown, the following steps are included:

[0055] Step S1, obtaining a silicon wafer with a surface having a crystal orientation of 100 after removing surface stains and an oxide layer as a silicon substrate 1;

[0056] Step S2, preparing a SiO2 insulating layer 2 on the upper surface of the silicon substrate 1, and preparing a patterned first Pt resistor 4 and a third Pt resistor 8 distributed along the length direction of the silicon substrate 1 on the upper surface of the SiO2 insulating layer 2;

[0057] Step S3, depositing a Si3N4 film 12 on the surface of the first Pt resistor 4 and the third Pt resistor 8, and etching to obtain a second Si3N4 film 5 and a third Si3N4 film 9;

[0058] Step S4, preparing patterned first Au interdigital electrodes 6 on both sides of the first Pt resistor 4 along the length direction of the silicon substrate 1, and preparing patterned second Au interdigital electrodes 10 on the upper surface of the third Si3N4 film 9;

[0059] Step S5, depositing a first Si3N4 film 3 on the lower surface of the silicon substrate 1, and scribing the first Si3N4 film 3 at both ends along the length direction of the silicon substrate 1;

[0060] Step S6, preparing a patterned second Pt resistor 7 on the lower surface of the first Si3N4 film 3, and preparing a PI film 11 on the upper surface of the second Au interdigital electrode 10 by spin coating, followed by wire bonding and packaging to obtain a salt spray environment parameter detection micro-nano sensor.

[0061] Specifically, in this embodiment, in step S6, the thickness of the prepared PI film 11 is 20 um.

[0062] In a preferred embodiment of the present invention, in step S2, the silicon substrate is first dry-oxidized for 150 minutes at 1100°C, and then wet-oxidized for 1450 minutes to obtain a uniform SiO2 insulating layer 2 with a double-sided thickness of 2um, and the SiO2 insulating layer 2 on the lower surface of the silicon substrate 1 is wet-etched and removed using a BOE solution.

[0063] In a preferred embodiment of the present invention, in step S2, the upper surface of the SiO2 insulating layer 2 is sequentially coated with glue, pre-baked, photolithographically coated, and developed, and a patterned first photoresist mask is prepared by post-baking after development, and then a layer of Cr is sputtered as an adhesion layer on the upper surface of the first photoresist mask by a magnetron sputtering process, and then a 50 / 200nm Pt metal layer is sputtered, and based on the photolithography pattern on the first photoresist mask, the Pt metal layer is etched by a lift-off process to obtain the first Pt resistor 4 and the third Pt resistor 8, respectively.

[0064] Specifically, in this embodiment, the process of preparing the second Pt resistor 7 in step S6 is the same as the process of preparing the first Pt resistor 4 and the third Pt resistor 8 in step S2.

[0065] In a preferred embodiment of the present invention, in step S3, a plasma chemical vapor deposition process is used to deposit a layer of Si3N4 film 12 with a thickness of 700 nm on the surface of the first Pt resistor and the third Pt resistor, and the upper surface of the Si3N4 film 12 is sequentially coated with glue, pre-baked, photolithographically, and developed, and a patterned second photoresist mask is prepared by post-baking after development, and then based on the photolithographic pattern on the second photoresist mask, the Si3N4 film 12 is etched by a reactive ion etching process to obtain a second Si3N4 film 5 and a third Si3N4 film 9.

[0066] In a preferred embodiment of the present invention, in step S4, a layer of Cr is sputtered as an adhesion layer on both sides of the first Pt resistor 4 along the length direction of the silicon substrate 1 and on the upper surface of the third Si3N4 film 9 by a magnetron sputtering process, and then a layer of 30 / 300nm Au metal layer is sputtered, and then the upper surface of the Au metal layer is coated with glue, pre-baked, photolithographic, and developed in sequence, and a patterned third photoresist mask is prepared by post-baking after development, and based on the photolithography pattern on the third photoresist mask, the Au metal layer is etched by an IBE process to obtain a patterned first Au interdigital electrode 6 and a second Au interdigital electrode 10.

[0067] In a preferred embodiment of the present invention, in step S5, a first Si3N4 film 3 with a thickness of 2 um is deposited on the lower surface of the silicon substrate 1 by a plasma chemical vapor deposition process.

[0068] Specifically, in this embodiment, the preparation method of the micro-nano sensor for detecting salt spray environmental parameters can be roughly divided into: 1) thermal oxidation of both sides of the silicon substrate to form silicon oxide; 2) wet etching of the lower surface using BOE solution to remove silicon oxide; 3) preparing Cr / Pt resistors and patterning on the SiO2 insulating layer using the lift-off process on the upper surface; 4) depositing SI3N4 film on the upper surface using the PECVD process; 5) etching the SI3N4 film on the upper surface using the RIE process; 6) preparing Cr / Au interdigital electrodes and patterning on the SiO2 insulating layer and SI3N4 film on the upper surface using the IBE process; 7) depositing SI3N4 insulating layer on the lower surface of the silicon substrate using the PECVD process; 8) etching the SI3N4 insulating layer on the lower surface using the RIE process to achieve dicing and release strain pressure; 9) preparing Cr / Pt resistors and patterning on the SI3N4 insulating layer on the lower surface using the lift-off process; 10) after the device of step 9) is wired and packaged, the preparation of the entire sensor can be completed.

[0069] Preferably, as a supplement to the above preparation method, step 3) preparing Cr / Pt resistors on the upper surface of the silicon substrate and patterning includes the following steps:

[0070] (1) performing photolithography (resin coating, pre-baking, alignment exposure, and development) on the upper surface of a silicon substrate to prepare a patterned photoresist mask;

[0071] (2) Sputtering a layer of Cr as an adhesion layer by magnetron sputtering process, and then sputtering a layer of Pt metal layer;

[0072] (3) The lift-off process (including photolithography, magnetron sputtering and ultrasonic stripping) is used to realize patterned Pt resistor.

[0073] Preferably, as a supplement to the above preparation method, step 6) preparing Cr / Au interdigital electrodes on the upper surface of the silicon substrate and patterning includes the following steps:

[0074] (1) A layer of Cr is sputtered as an adhesion layer on the SiO2 insulating layer and the SI3N4 film by a magnetron sputtering process, and then a layer of Au metal layer is sputtered;

[0075] (2) performing photolithography (coating, pre-baking, alignment exposure, and development) on the surface of the Au metal layer to prepare a patterned photoresist mask;

[0076] (3) The Cr / Au layer is etched using the IBE process to achieve patterned Au interdigital electrodes.

[0077] The present invention also provides a salt spray environment parameter detection micro-nano sensor measurement method, which is applied to the above-mentioned salt spray environment parameter detection micro-nano sensor, such as Figure 5 As shown, the following steps are included:

[0078] Step A1, placing a salt spray environment parameter detection micro-nano sensor and a hygrothermometer in a salt spray test chamber to measure the temperature and humidity in the salt spray test chamber;

[0079] Step A2, keeping the temperature in the salt spray test box unchanged, continuously spraying a neutral salt spray solution to the salt spray environment parameter detection micro-nano sensor, and monitoring the resistance value change and current temperature of the first Pt resistor 4 and the second Pt resistor 7, the capacitance change and current humidity of the second Au interdigital electrode 10, and the current and voltage changes between the two first Au interdigital electrodes 6 in real time, and adding them to the monitoring data;

[0080] Step A3, maintaining the temperature in the salt spray test chamber constant and adjusting the humidity or maintaining the humidity in the salt spray test chamber constant and adjusting the temperature, and obtaining the relationship between the temperature and humidity and the change of conductivity and the surface liquid film wetting time according to the monitoring data;

[0081] Step A4, based on the relationship, through temperature and humidity calibration and conductivity calculation formula σ=K / R S As well as the relationship between capacitance and dielectric constant C=nεlh / Ws+nε / 2, the corresponding temperature and humidity, wetting time and conductivity parameters are obtained.

[0082] Specifically, in this embodiment, the salt spray environment parameter detection micro-nano sensor measurement method provided by the present invention uses the above-mentioned salt spray environment parameter detection micro-nano sensor, firstly obtains a PI film of a certain thickness on the humidity Au interdigital electrode by spin coating, and then performs a simulation test process on the salt spray environment parameter micro-nano sensor as described above, and tests and calibrates the salt spray environment parameter micro-nano sensor, by controlling the temperature and humidity of the salt spray test machine and the standard test solutions of known concentrations with different conductivities, connecting an impedance analyzer and an electrochemical workstation, and measuring the corresponding resistance, capacitance and conductivity on the working electrode, and comparing the temperature calibration and the conductivity calculation formula σ=K / R S As well as the relationship between capacitance and dielectric constant C = nεlh / Ws+nε / 2, a linear coupling relationship with temperature, humidity and conductivity is established.

[0083] Preferably, the specific test process is as follows: (1) placing a salt spray environment parameter detection micro-nano sensor and a commercial thermometer and hygrometer in a salt spray test chamber to measure the temperature and humidity in the test chamber before the experiment; (2) keeping the temperature constant, spraying the test chamber with a neutral salt spray solution (NSS) continuously, and monitoring the resistance change of the temperature resistor and the current temperature, the capacitance change of the humidity Au interdigital electrode and the current humidity, and the current and voltage change between the conductivity Au interdigital electrodes in real time; (3) adjusting the humidity at a fixed temperature or adjusting the temperature at a fixed humidity to obtain the relationship between the temperature and humidity and the conductivity change and the surface liquid film wetting time; (4) through temperature and humidity calibration and conductivity calculation formula σ=K / R S As well as the relationship between capacitance and dielectric constant C=nεlh / Ws+nε / 2, the corresponding parameters such as temperature and humidity, wetting time and conductivity are obtained.

[0084] Although the disclosure is disclosed as above, the protection scope of the disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the disclosure, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A salt spray environment parameter detection micro-nano sensor, characterized in that: include: A silicon substrate (1), wherein a SiO2 insulating layer (2) is provided on the upper surface of the silicon substrate (1), a first Si3N4 film (3) is deposited on the lower surface of the silicon substrate (1), and an adhesion layer is provided on the surfaces of the SiO2 insulating layer (2) and the first Si3N4 film (3); A first Pt resistor (4) is arranged on the upper surface of the adhesive layer on the SiO2 insulating layer (2), a second Si3N4 film (5) is deposited on the upper surface of the first Pt resistor (4), and patterned first Au interdigital electrodes (6) in the shape of hollow window grilles are arranged on both sides of the first Pt resistor (4) along the length direction of the silicon substrate (1); a second Pt resistor (7) disposed on the lower surface of the adhesion layer on the first Si3N4 film (3); a third Pt resistor (8) disposed on the upper surface of the adhesion layer on the SiO2 insulating layer (2) and located on one side of the first Pt resistor (4) along the length direction of the silicon substrate (1); a third Si3N4 film (9) is deposited on the surface of the third Pt resistor (8); a patterned second Au interdigital electrode (10) is disposed on the upper surface of the third Si3N4 film (9); and a PI film (11) is deposited on the upper surface of the second Au interdigital electrode (10); The first Au interdigital electrode (6) comprises: Two rectangular pads (61), the two rectangular pads (61) are respectively connected to one end of a long electrode connector (62) on one side along the width direction of the silicon substrate (1), and a plurality of first long metal electrodes (63) and second long metal electrodes (64) are arranged alternately and spaced along the length direction of the two long electrode connectors (62), one end of each of the first long metal electrodes (63) is fixedly connected to one of the long electrode connectors (62), and a gap exists between the other end of each of the first long metal electrodes (63) and the other long electrode connector (62), and one end of each of the second long metal electrodes (64) is fixedly connected to the other long electrode connector (62). A strip electrode connector (62) is fixedly connected, a gap is provided between the other end of each second strip metal electrode (64) and one of the strip electrode connectors (62), and a plurality of first T-shaped metal electrodes (65) and second T-shaped metal electrodes (66) are arranged alternately and spaced along their own length direction between adjacent first strip metal electrodes (63) and second strip metal electrodes (64), a protrusion (67) of each first T-shaped metal electrode (65) faces one of the strip electrode connectors (62), and a protrusion (67) of each second T-shaped metal electrode (66) faces another of the strip electrode connectors (62).

2. The salt spray environment parameter detection micro-nano sensor according to claim 1, characterized in that: The first Pt resistor (4) and the second Pt resistor (7) are serpentine Pt resistors with the same parameters, and the position of the first Pt resistor (4) on the SiO2 insulating layer (2) and the position of the second Pt resistor (7) on the first Si3N4 film (3) overlap along the height direction of the silicon substrate (1).

3. The salt spray environment parameter detection micro-nano sensor according to claim 1, characterized in that: The third Pt resistor (8) is a circular Pt resistor low-power heater.

4. A method for preparing a micro-nano sensor for detecting salt spray environmental parameters, characterized in that: The salt spray environment parameter detection micro-nano sensor according to any one of claims 1 to 3 comprises the following steps: Step S1, obtaining a silicon wafer with a surface having a (100) crystal orientation after removing surface stains and an oxide layer as the silicon substrate (1); Step S2, preparing the SiO2 insulating layer (2) on the upper surface of the silicon substrate (1), and preparing the first Pt resistor (4) and the third Pt resistor (8) on the upper surface of the SiO2 insulating layer (2) and distributed along the length direction of the silicon substrate (1); Step S3, depositing a Si3N4 film (12) on the surface of the first Pt resistor (4) and the third Pt resistor (8), and etching to obtain the second Si3N4 film (5) and the third Si3N4 film (9); Step S4, preparing the first Au interdigital electrodes (6) in a pattern on both sides of the first Pt resistor (4) along the length direction of the silicon substrate (1), and preparing the second Au interdigital electrodes (10) in a pattern on the upper surface of the third Si3N4 film (9); Step S5, depositing the first Si3N4 film (3) on the lower surface of the silicon substrate (1), and scribing the first Si3N4 film (3) at both ends along the length direction of the silicon substrate (1); Step S6, preparing the patterned second Pt resistor (7) on the lower surface of the first Si3N4 film (3), and preparing the PI film (11) on the upper surface of the second Au interdigital electrode (10) by spin coating, followed by wire bonding and packaging to obtain the salt spray environment parameter detection micro-nano sensor.

5. The method for preparing a micro-nano sensor for detecting salt spray environmental parameters according to claim 4, characterized in that: In the step S2, the silicon substrate (1) is first dry-oxidized for 50 minutes at 1100° C., and then wet-oxidized for 450 minutes to obtain a uniform SiO2 insulating layer (2) with a double-sided thickness of 2 μm, and the SiO2 insulating layer (2) on the lower surface of the silicon substrate (1) is removed by wet etching with a BOE solution.

6. The method for preparing a micro-nano sensor for detecting salt spray environmental parameters according to claim 4, characterized in that: In the step S2, the upper surface of the SiO2 insulating layer (2) is coated with glue, pre-baked, photolithographically processed, and developed in sequence, and a patterned first photoresist mask is prepared by post-baking after development, and then a layer of Cr as the adhesion layer is sputtered on the upper surface of the first photoresist mask by a magnetron sputtering process, and then a layer of 50 / 200nm Pt metal layer is sputtered, and based on the photolithographic pattern on the first photoresist mask, the Pt metal layer is etched by a lift-off process to obtain the first Pt resistor (4) and the third Pt resistor (8), respectively.

7. The method for preparing a micro-nano sensor for detecting salt spray environmental parameters according to claim 4, characterized in that: In the step S3, a layer of the Si3N4 film (12) with a thickness of 700 nm is deposited on the surface of the first Pt resistor and the third Pt resistor by using a plasma chemical vapor deposition process, and the upper surface of the Si3N4 film (12) is sequentially coated with glue, pre-baked, photolithographically processed, and developed. After development, a patterned second photoresist mask is prepared by post-baking. Subsequently, based on the photolithographic pattern on the second photoresist mask, the Si3N4 film (12) is etched by using a reactive ion etching process to obtain the second Si3N4 film (5) and the third Si3N4 film (9).

8. The method for preparing a micro-nano sensor for detecting salt spray environmental parameters according to claim 4, characterized in that: In the step S4, a layer of Cr is sputtered as the adhesion layer on both sides of the first Pt resistor (4) along the length direction of the silicon substrate (1) and on the upper surface of the third Si3N4 film (9) by a magnetron sputtering process, and then a layer of 30 / 300nm Au metal layer is sputtered, and then the upper surface of the Au metal layer is coated with glue, pre-baked, photolithographically, and developed in sequence, and a patterned third photoresist mask is prepared by post-baking after development, and based on the photolithographic pattern on the third photoresist mask, the Au metal layer is etched by an IBE process to obtain the patterned first Au interdigital electrode (6) and the second Au interdigital electrode (10).

9. The method for preparing a micro-nano sensor for detecting salt spray environmental parameters according to claim 4, characterized in that: In the step S5, a first Si3N4 film (3) with a thickness of 2 μm is deposited on the lower surface of the silicon substrate (1) using a plasma chemical vapor deposition process.

10. A method for measuring salt spray environment parameter detection micro-nano sensor, applied to the salt spray environment parameter detection micro-nano sensor as claimed in any one of claims 1 to 3, comprising the following steps: Step A1, placing the salt spray environment parameter detection micro-nano sensor and the humidity thermometer in a salt spray test chamber to measure the temperature and humidity in the salt spray test chamber; Step A2, maintaining the temperature in the salt spray test box unchanged, continuously spraying a neutral salt spray solution to the salt spray environment parameter detection micro-nano sensor, and monitoring in real time the resistance value change and current temperature of the first Pt resistor (4) and the second Pt resistor (7), the capacitance change and current humidity of the second Au interdigital electrode (10), and the current and voltage changes between the two first Au interdigital electrodes (6), and adding the changes to the monitoring data; Step A3, maintaining the temperature in the salt spray test box constant and adjusting the humidity or maintaining the humidity in the salt spray test box constant and adjusting the temperature, and obtaining the relationship between the temperature and humidity and the change of conductivity and the surface liquid film wetting time according to the monitoring data; Step A4: Based on the relationship, the temperature and humidity are calibrated and the conductivity is calculated using the formula σ=K / R S As well as the relationship between capacitance and dielectric constant C=nεlh / Ws+nε / 2, the corresponding temperature and humidity, wetting time and conductivity parameters are obtained.

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