A salt spray environment parameter detection micro-nano sensor and a preparation and measurement method thereof

Abstract

The application provides a salt fog environment parameter detection micro-nano sensor and a preparation and measurement method thereof, and comprises a silicon substrate, an upper surface and a lower surface of which are respectively provided with a SiO2 insulating layer and a first Si3N4 film; a first Pt resistor is arranged on the upper surface of the SiO2 insulating layer, the upper surface is deposited with a second Si3N4 film, and the first Pt resistor is provided with first Au interdigital electrodes on both sides in the length direction of the silicon substrate; a second Pt resistor is arranged on the lower surface of the first Si3N4 film; a third Pt resistor is arranged on the upper surface of an adhesive layer on the SiO2 insulating layer, the surface is deposited with a third Si3N4 film, the upper surface of the third Si3N4 film is provided with a patterned second Au interdigital electrode, and the upper surface of the second Au interdigital electrode is deposited with a PI film. The beneficial effect is that the 'hollow window flower-shaped' interdigital microelectrode can reduce the wetting time, realize high-precision measurement of the sensor body, salt fog gas temperature and heat exchange, eliminate the influence of temperature and humidity on conductivity detection through data compensation, accelerate the desorption process, and reduce the wet hysteresis.

Description

TECHNICAL FIELD

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

[0002] Corrosion is one of the serious problems affecting the health state of aviation structures, and is a destructive erosion process caused by chemical or electrochemical reaction of metal and surrounding environment. According to relevant statistics, the economic loss caused by corrosion each year is much higher than the total of natural disasters and other accidents. Therefore, it is necessary and urgent to carry out online monitoring of the corrosion state of flight equipment and corrosion environmental factors. The detection of atmospheric and salt mist environmental parameters as main environmental factors is directly related to the safety of flight equipment navigation.

[0003] Typical salt mist environmental parameters include temperature, humidity, chloride ion concentration, salt concentration and the like. At present, domestic enterprises have started late in the detection of salt mist environmental parameters, and there are still many problems in the products, for example, the service life of the reference electrode in the chloride ion detection unit is limited, and long-term continuous monitoring of the sensor cannot be realized. The wetting time as one of the negative indicators of the salt mist environmental parameters is one of the negative indicators of the salt mist environmental parameters. At present, the products for measuring this parameter mostly use the scheme of ordinary interdigital electrodes, but there are problems such as high humidity requirement, long reaction time and weak anti-interference performance.

[0004] The salt mist environment is complex and changeable, and there are many test interference factors. There is also a cross interference problem between multiple sensing units of the sensor. For example, the temperature and humidity interfere with the liquid film formation of the conductivity sensing area, directly causing the deviation of the conductivity test. The difference between the temperature of the sensor body and the environmental temperature directly affects the mass transfer of chloride ions between the liquid film and the salt mist gas, which also causes the deviation of the conductivity test. In addition, the sensor is used on an aircraft, and the response time of the sensor is required to be short, otherwise the large sensing hysteresis will cause the deviation of the corrosion state evaluation.

[0005] Therefore, the measurement accuracy of the current salt mist environmental parameter sensor is not high, and the detected conductivity is greatly affected by temperature and humidity, and the wetting time is long and the wet hysteresis is serious. SUMMARY

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

[0007] To solve the above problems, the present application provides a salt mist environmental parameter detection micro-nano sensor, comprising:

[0008] a silicon substrate, a top surface of the silicon substrate is provided with a SiO2 insulating layer, a bottom surface of the silicon substrate is deposited with a first Si3N4 thin film, a surface of the SiO2 insulating layer and the first Si3N4 thin film is provided with an adhesion layer;

[0009] a first Pt resistor, a top surface of the adhesion layer on the SiO2 insulating layer, a top surface of the first Pt resistor is deposited with a second Si3N4 thin film, the first Pt resistor is provided with a first Au interdigital electrode in a patterned fret-shaped form along two sides of the silicon substrate in a length direction;

[0010] a second Pt resistor, a bottom surface of the adhesion layer on the first Si3N4 thin film;

[0011] a third Pt resistor, a top surface of the adhesion layer on the SiO2 insulating layer and located at one side of the first Pt resistor in the length direction of the silicon substrate, a surface of the third Pt resistor is deposited with a third Si3N4 thin film, a top surface of the third Si3N4 thin film is provided with a second Au interdigital electrode in a patterned form, a top surface of the second Au interdigital electrode is deposited with a PI thin film;

[0012] the first Au interdigital electrode comprises:

[0013] two rectangular pads, one end of each of the two rectangular pads is connected to one end of a long electrode connecting piece along one side of the silicon substrate in a width direction, a plurality of first long metal electrodes and second long metal electrodes are arranged alternately and spaced along a length direction of the long electrode connecting piece, one end of each of the first long metal electrodes is fixedly connected to one of the long electrode connecting pieces, the other end of each of the first long metal electrodes has a gap with the other long electrode connecting piece, one end of each of the second long metal electrodes is fixedly connected to the other long electrode connecting piece, the other end of each of the second long metal electrodes has a gap with one of the long electrode connecting pieces, and a plurality of first T-shaped metal electrodes and second T-shaped metal electrodes are arranged alternately and spaced along a length direction of the long electrode connecting piece 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 connecting pieces, and a protrusion of each of the second T-shaped metal electrodes faces the other long electrode connecting piece.

[0014] Preferably, the first Pt resistor and the second Pt resistor are serpentine Pt resistors with the same parameters, and the first Pt resistor and the second Pt resistor are overlapped along a height direction of the silicon substrate.

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

[0016] The application also provides a preparation method of 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] In step S1, a silicon wafer with a (100) crystal direction after removing surface stains and an oxide layer is obtained as the silicon substrate.

[0018] In step S2, the SiO2 insulating layer is prepared on the upper surface of the silicon substrate, and the patterned first Pt resistor and the third Pt resistor distributed along the length direction of the silicon substrate are respectively prepared on the upper surface of the SiO2 insulating layer.

[0019] In step S3, the Si3N4 thin film is deposited on the surface of the first Pt resistor and the third Pt resistor, and the second Si3N4 thin film and the third Si3N4 thin film are etched.

[0020] In step S4, the patterned first Au interdigital electrode is prepared on both sides of the first Pt resistor along the length direction of the silicon substrate, and the patterned second Au interdigital electrode is prepared on the upper surface of the third Si3N4 thin film.

[0021] In step S5, the first Si3N4 thin film is deposited on the lower surface of the silicon substrate, and the first Si3N4 thin film is scribed at both ends along the length direction of the silicon substrate.

[0022] In step S6, the patterned second Pt resistor is prepared on the lower surface of the first Si3N4 thin film, and the PI thin film is prepared on the upper surface of the second Au interdigital electrode by using a spin coating method, and then wire bonding and packaging are performed to obtain the salt spray environment parameter detection micro-nano sensor.

[0023] Preferably, in step S2, the silicon substrate is first dry-oxygen oxidized at 1100℃ for 50min, and then wet-oxygen oxidized for 450min to obtain a uniform SiO2 insulating layer with a thickness of 2um on both surfaces, 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 the step S2, a first photoresist mask is prepared by successively performing glue coating, pre-baking, photoetching and developing on the upper surface of the SiO2 insulating layer, followed by post-baking after developing, then a layer of Cr is sputtered on the upper surface of the first photoresist mask as the adhesion layer by using a magnetron sputtering process, and then a 50 / 200 nm Pt metal layer is sputtered, and the Pt metal layer is etched by using a lift-off process based on the photoetching pattern on the first photoresist mask to obtain the first Pt resistor and the third Pt resistor.

[0025] Preferably, in the step S3, a 700 nm thick Si3N4 film is deposited on the surfaces of the first Pt resistor and the third Pt resistor by using a plasma chemical vapor deposition process, a second photoresist mask is prepared by successively performing glue coating, pre-baking, photoetching and developing on the upper surface of the Si3N4 film, followed by post-baking after developing, and then the Si3N4 film is etched by using a reactive ion etching process based on the photoetching pattern on the second photoresist mask to obtain the second Si3N4 film and the third Si3N4 film.

[0026] Preferably, in the step S4, a layer of Cr is sputtered as the adhesion layer on the two sides of the first Pt resistor along the length direction of the silicon substrate and on the upper surface of the third Si3N4 film by using a magnetron sputtering process, and then a 30 / 300 nm Au metal layer is sputtered, and then a third photoresist mask is prepared by successively performing glue coating, pre-baking, photoetching and developing on the upper surface of the Au metal layer, followed by post-baking after developing, and then the Au metal layer is etched by using an IBE process based on the photoetching pattern on the third photoresist mask to obtain the first Au interdigital electrode and the second Au interdigital electrode.

[0027] Preferably, in the step S5, a 2 um thick first Si3N4 film is deposited on the lower surface of the silicon substrate by using a plasma chemical vapor deposition process.

[0028] The application also provides a measurement method of 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 includes the following steps:

[0029] In step A1, the salt spray environment parameter detection micro-nano sensor and a hygrometer are placed in a salt spray test box to measure the temperature and humidity in the salt spray test box.

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

[0031] Step A3, keeping the temperature in the salt spray test chamber unchanged to regulate the humidity or keeping the humidity in the salt spray test chamber unchanged to regulate the temperature, obtaining the relationship between temperature, humidity and conductivity changes and surface liquid film wetting time according to the monitoring data;

[0032] Step A4, based on the relationship, obtaining the corresponding temperature, humidity, wetting time and conductivity parameters through temperature and humidity calibration and conductivity calculation formula σ=K / R S and the relationship between capacitance and dielectric constant C=nεlh / Ws+nε / 2.

[0033] The present application has the following beneficial effects: the first Au interdigital electrode with a "window flower shape" is designed, the small gap between the sensitive electrode and the proton film and the large contact area between the liquid film and the sensitive electrode are realized, so as to reduce the wetting time, the temperature electrodes with the same parameters, i.e. the first Pt resistance and the second Pt resistance, are prepared on both sides of the silicon substrate based on the lift-off process, the areas of the first Pt resistance and the second Pt resistance overlap in the height direction, the high-precision measurement of the sensor body, the salt spray gas temperature and the heat exchange is realized, the data compensation for the conductivity test is used, the temperature, humidity and conductivity detection pieces are prepared in the same micro area based on the MEMS technology, the influence of temperature and humidity on the conductivity detection is reduced through data compensation, and the small power heater, i.e. the second Pt resistance, is designed and added at the bottom of the humidity detection piece, which can accelerate the desorption process and reduce the humidity hysteresis. BRIEF DESCRIPTION OF DRAWINGS

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

[0035] Figure 2 It is a top view of the first Au interdigital electrode with a window flower shape of the present application;

[0036] Figure 3 It is a step flow chart of the preparation method of the present application;

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

[0038] Figure 5 It is a step flow chart of the measurement method of the present application;

[0039] Explanation of reference signs: 1, silicon substrate; 2, SiO2insulating layer; 3, first Si3N4film; 4, first Pt resistor; 5, second Si3N4film; 6, first Au interdigital electrode; 61, rectangular pad; 62, long electrode connecting piece; 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 Si3N4film; 10, second Au interdigital electrode; 11, PI film; 12, Si3N4film. DETAILED DESCRIPTION

[0040] In order to make the above-mentioned objectives, features and advantages of the present application more apparent and comprehensible, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0041] In the preferred embodiments of the present application, based on the above-mentioned problems existing in the prior art, a salt spray environment parameter detection micro-nano sensor is provided, as shown in Figure 1 and Figure 2 , comprising:

[0042] A silicon substrate 1, the upper surface of the silicon substrate 1 is provided with a SiO2insulating layer 2, and the lower surface of the silicon substrate 1 is deposited with a first Si3N4film 3, and the surfaces of the SiO2insulating layer 2 and the first Si3N4film 3 are both provided with an adhesion layer;

[0043] A first Pt resistor 4 is arranged on the upper surface of the adhesion layer on the SiO2insulating layer 2, and the upper surface of the first Pt resistor 4 is deposited with a second Si3N4film 5, and the first Pt resistor 4 is provided with a patterned first Au interdigital electrode 6 in the shape of a fretwork window on both sides along the length direction of the silicon substrate 1;

[0044] A second Pt resistor 7 is arranged on the lower surface of the adhesion layer on the first Si3N4film 3;

[0045] A third Pt resistor 8 is arranged on the upper surface of the adhesion layer on the SiO2insulating layer 2 and located on one side of the first Pt resistor 4 along the length direction of the silicon substrate 1, and the surface of the third Pt resistor 8 is deposited with a third Si3N4film 9, and the upper surface of the third Si3N4film 9 is provided with a patterned second Au interdigital electrode 10, and the upper surface of the second Au interdigital electrode 10 is deposited with a PI film 11;

[0046] The first Au interdigital electrode 6 comprises:

[0047] Two rectangular pads 61 are respectively connected to one end of two long electrode connecting members 62 along one side of the width direction of the silicon substrate 1, and a plurality of first long metal electrodes 63 and second long metal electrodes 64 are alternately and spacedly arranged along the length direction of the long electrode connecting members 62 between the two long electrode connecting members 62, one end of each first long metal electrode 63 is fixedly connected to one long electrode connecting member 62, and the other end of each first long metal electrode 63 has a gap with the other long electrode connecting member 62, one end of each second long metal electrode 64 is fixedly connected to the other long electrode connecting member 62, and the other end of each second long metal electrode 64 has a gap with one long electrode connecting member 62, and a plurality of first T-shaped metal electrodes 65 and second T-shaped metal electrodes 66 are alternately and spacedly arranged along the length direction of the long electrode connecting members 62 between adjacent first long metal electrodes 63 and second long metal electrodes 64, the protrusion 67 of each first T-shaped metal electrode 65 faces one long electrode connecting member 62, and the protrusion 67 of each second T-shaped metal electrode 66 faces the other long electrode connecting member 62.

[0048] Specifically, in the 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, and 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 on the right long electrode connecting member 62, the second long metal electrode 64 is fixed on the left long electrode connecting member 62, the first long metal 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 leftmost side, the protrusion 67 of the first T-shaped metal electrode 65 faces the right long electrode connecting member 62, the second T-shaped metal electrode 66 is located on the rightmost side, the protrusion 67 of the second T-shaped metal electrode 66 faces the left long electrode connecting member 62, and 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 the preferred embodiment of the application, the first Pt resistance 4 and the second Pt resistance 7 are serpentine Pt resistances with the same parameters, and the positions of the first Pt resistance 4 on the SiO2 insulating layer 2 and the second Pt resistance 7 on the first Si3N4 thin film 3 overlap along the height direction of the silicon substrate 1.

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

[0051] Specifically, in the embodiment, the application is based on MEMS technology, and silicon or silicon oxide or silicon nitride is used as a substrate, and a serpentine Pt resistance is used for detecting temperature at corresponding positions on the front and back surfaces of the substrate; an Au interdigital electrode system is prepared by a magnetron sputtering technology and an ion beam etching technology, and humidity and conductivity are detected.

[0052] Preferably, the salt spray environment parameter detection micro-nano sensor has the following advantages: 1) the first Au interdigital electrode 6 is used to measure the wetting time, so that a small gap between the sensitive electrode and the proton film and a large contact area between the liquid film and the sensitive electrode are realized; 2) double temperature detection is used to realize solid-gas interface heat exchange measurement and high-precision measurement, and data compensation; 3) the temperature, humidity and conductivity sensors are integrated in the same micro area based on the MEMS technology, so that miniaturization, low cost and batch production are realized; 4) the circular Pt resistance low-power heater is used to accelerate the desorption process and reduce the wet hysteresis, and the application realizes low-cost and integrated batch production of the salt spray environment parameter detection micro-nano sensor, and provides a core sensor for corrosion state monitoring and prediction of flight equipment by combining with a low-power high-precision signal acquisition circuit and a data fusion algorithm.

[0053] Preferably, the salt spray environment parameter detection micro-nano sensor has higher measurement precision and lower cost under the premise of ensuring multi-parameter integration, and has great practical application value.

[0054] The application further provides a preparation method of the salt spray environment parameter detection micro-nano sensor, which is applied to the salt spray environment parameter detection micro-nano sensor. Figure 3 and Figure 4 As shown in the drawings, the method comprises the following steps:

[0055] In step S1, a silicon wafer with a 100 crystal orientation after removing surface stains and an oxide layer is obtained as a silicon substrate 1;

[0056] In step S2, a SiO2 insulating layer 2 is prepared on the upper surface of the silicon substrate 1, and a patterned first Pt resistance 4 and a third Pt resistance 8 distributed along the length direction of the silicon substrate 1 are respectively prepared on the upper surface of the SiO2 insulating layer 2;

[0057] In step S3, Si3N4 films 12 are deposited on the surfaces of the first Pt resistance 4 and the third Pt resistance 8, and a second Si3N4 film 5 and a third Si3N4 film 9 are etched;

[0058] In step S4, a patterned first Au interdigital electrode 6 is prepared on both sides of the first Pt resistance 4 along the length direction of the silicon substrate 1, and a patterned second Au interdigital electrode 10 is prepared 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 along the two ends of the silicon substrate 1 in the length direction;

[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 using a spin coating method, and then performing wire bonding and packaging to obtain a salt mist environmental parameter detection micro-nano sensor.

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

[0062] In the preferred embodiment of the application, in step S2, the silicon substrate 1 is first dry-oxygen oxidized at 1100°C for 150 min, and then wet-oxygen oxidized for 1450 min to obtain a uniform SiO2 insulating layer 2 with a thickness of 2 um on both surfaces, and the SiO2 insulating layer 2 on the lower surface of the silicon substrate 1 is removed by wet etching with a BOE solution.

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

[0064] Specifically, in the 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 the preferred embodiment of the application, in step S3, a layer of Si3N4 film 12 with a thickness of 700 nm is deposited on the surfaces of the first Pt resistor and the third Pt resistor by using a plasma chemical vapor deposition process, the upper surface of the Si3N4 film 12 is sequentially coated with glue, pre-baked, photoetched, developed, and post-baked after development to prepare a patterned second photoresist mask, and then based on the photoetching pattern on the second photoresist mask, a reactive ion etching process is used to etch the Si3N4 film 12 to obtain the second Si3N4 film 5 and the third Si3N4 film 9.

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

[0067] In the preferred embodiment of the present application, 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 using a plasma chemical vapor deposition process.

[0068] Specifically, in the present embodiment, the preparation method of the salt spray environment parameter detection micro-nano sensor can be roughly divided into the following steps: 1) thermal oxidation of both surfaces of the silicon substrate to form silicon oxide; 2) removal of the silicon oxide on the lower surface by wet etching with a BOE solution; 3) preparation of a Cr / Pt resistor and patterning on the SiO2 insulating layer on the upper surface by using a lift-off process; 4) deposition of a SI3N4 film on the upper surface by using a PECVD process; 5) completion of the patterning of the SI3N4 film on the upper surface by using an RIE process; 6) preparation of a Cr / Au interdigital electrode and patterning on the SiO2 insulating layer and the SI3N4 film on the upper surface by using an IBE process; 7) deposition of a SI3N4 insulating layer on the lower surface of the silicon substrate by using a PECVD process; 8) etching of the SI3N4 insulating layer on the lower surface by using an RIE process to achieve a scribe lane and release the strain pressure; 9) preparation of a Cr / Pt resistor and patterning on the SI3N4 insulating layer on the lower surface by using a lift-off process; and 10) after wire bonding and packaging of the device of step 9), the preparation of the entire sensor is completed.

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

[0070] (1) performing photoetching (coating glue, pre-baking, aligning and exposing, and developing) on the upper surface of the silicon substrate to prepare a patterned photoresist mask;

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

[0072] (3) achieving a patterned Pt resistor by using a lift-off process (processes including photoetching process, magnetron sputtering process, and ultrasonic peeling process).

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

[0074] (1) sputtering a layer of Cr as an adhesion layer on the SiO2 insulating layer and the Si3N4 film using a magnetron sputtering process, and then sputtering a layer of Au metal layer;

[0075] (2) performing photoetching (gluing, pre-baking, aligning exposure, and developing) on the surface of the Au metal layer to prepare a patterned photoresist mask;

[0076] (3) etching the Cr / Au layer using an IBE process to realize the patterned Au interdigital electrode.

[0077] The application also provides a measurement method of the salt mist environment parameter detection micro-nano sensor, which is applied to the above salt mist environment parameter detection micro-nano sensor, as shown in the figure, comprising the following steps: Figure 5

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

[0079] Step A2, keeping the temperature in the salt mist test chamber unchanged, continuously spraying a neutral salt mist solution to the salt mist environment parameter detection micro-nano sensor, and monitoring the resistance wire resistance value changes and the current temperature of the first Pt resistor 4 and the second Pt resistor 7, the capacitance changes and the 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 them to the monitoring data;

[0080] Step A3, keeping the temperature in the salt mist test chamber unchanged to regulate the humidity or keeping the humidity in the salt mist test chamber unchanged to regulate the temperature, and obtaining the relationship between the temperature and humidity and the conductivity changes and the surface liquid film wetting time according to the monitoring data;

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

[0082] ​Specifically, in the present embodiment, the salt spray environment parameter detection micro-nano sensor measurement method provided by the present application uses the above-mentioned salt spray environment parameter detection micro-nano sensor, first obtains a PI film with a certain thickness on the humidity Au interdigital electrode by spin coating method, then performs a simulation test process on the salt spray environment parameter micro-nano sensor as described above, tests and calibrates the salt spray environment parameter micro-nano sensor, measures the corresponding resistance, capacitance and conductance on the working electrode by controlling the temperature and humidity of the salt spray tester and the standard test solution with known concentration of different conductivities, connecting the impedance analyzer and the electrochemical workstation, and through temperature calibration comparison and the conductivity calculation formula σ=K / R S and the relationship between capacitance and dielectric constant C=nεlh / Ws+nε / 2, to establish a linear coupling relationship with temperature and humidity and conductivity.

[0083] Preferably, the specific test process is as follows: (1) place the salt spray environment parameter detection micro-nano sensor and the commercial humidity meter in the salt spray test box, and measure the temperature and humidity in the test box before the experiment; (2) fix the temperature unchanged, make the test box continuously spray neutral salt spray solution (NSS), and real-time monitor the resistance wire resistance value change of temperature resistance and the current temperature, the capacitance change of humidity Au interdigital electrode and the current humidity, and the current and voltage change between conductivity Au interdigital electrode; (3) fix the temperature to regulate the humidity or fix the humidity to regulate the temperature, and get the relationship between temperature and humidity and conductivity change and surface liquid film wetting time; (4) through temperature and humidity calibration and conductivity calculation formula σ=K / R S and the relationship between capacitance and dielectric constant C=nεlh / Ws+nε / 2, to get the corresponding temperature and humidity and wetting time and conductivity parameters.

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

Claims

1. A salt fog environment parameter detection micro-nano sensor, characterized in that, The application relates to a silicon substrate (1) provided with a SiO2 insulating layer (2) on the upper surface, a first Si3N4 film (3) deposited on the lower surface, an adhesion layer provided on the surfaces of the SiO2 insulating layer (2) and the first Si3N4 film (3), a first Pt resistor (4) provided on the upper surface of the adhesion layer on the SiO2 insulating layer (2), a second Si3N4 film (5) deposited on the upper surface of the first Pt resistor (4), a first Au interdigital electrode (6) in a patterned fret-shaped form provided on both sides of the first Pt resistor (4) along the length direction of the silicon substrate (1), a second Pt resistor (7) provided on the lower surface of the adhesion layer on the first Si3N4 film (3), a third Pt resistor (8) provided 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) deposited on the surface of the third Pt resistor (8), a second Au interdigital electrode (10) provided on the upper surface of the third Si3N4 film (9), and a PI film (11) deposited on the upper surface of the second Au interdigital electrode (10). The first Au interdigital electrode (6) comprises two rectangular pads (61) respectively connected to one end of a long electrode connecting piece (62) on one side along the width direction of the silicon substrate (1), a plurality of first long metal electrodes (63) and second long metal electrodes (64) alternately arranged along the length direction of the long electrode connecting piece (62) between the two long electrode connecting pieces (62), one end of each first long metal electrode (63) fixedly connected to one long electrode connecting piece (62), a gap between the other end of each first long metal electrode (63) and the other long electrode connecting piece (62), one end of each second long metal electrode (64) fixedly connected to the other long electrode connecting piece (62), a gap between the other end of each second long metal electrode (64) and one long electrode connecting piece (62), and a plurality of first T-shaped metal electrodes (65) and second T-shaped metal electrodes (66) alternately arranged along the length direction of the long electrode connecting piece (62) between adjacent first long metal electrodes (63) and second long metal electrodes (64), wherein the protrusions (67) of the first T-shaped metal electrodes (65) face one long electrode connecting piece (62), and the protrusions (67) of the second T-shaped metal electrodes (66) face the other long electrode connecting piece (62). The first Pt resistor (4) and the second Pt resistor (7) are serpentine Pt resistors with the same parameters, and the positions of the first Pt resistor (4) on the SiO2 insulating layer (2) and the second Pt resistor (7) on the first Si3N4 film (3) overlap along the height direction of the silicon substrate (1). ​ ​ ​ ​ 2. The salt-fog environmental parameter detection micro-nano sensor according to claim 1, characterized in that, ​ 3. The salt-fog environmental parameter detection micro-nano sensor according to claim 1, characterized in that, The third Pt resistance (8) is a circular Pt resistance small power heater.

4. A method for preparing a salt-mist environmental parameter detection micro-nano sensor, characterized in that, The application is applied to the salt mist environment parameter detection micro-nano sensor in any one of claims 1-3, comprising the following steps: In step S1, a silicon wafer with a (100) crystal direction after removing surface stains and an oxide layer is obtained as the silicon substrate (1). In step S2, the SiO2insulating layer (2) is prepared on the upper surface of the silicon substrate (1), and the patterned first Pt resistance (4) and the third Pt resistance (8) distributed along the length direction of the silicon substrate (1) are respectively prepared on the upper surface of the SiO2insulating layer (2). In step S3, the Si3N4thin film (12) is deposited on the surface of the first Pt resistance (4) and the third Pt resistance (8), and the second Si3N4thin film (5) and the third Si3N4thin film (9) are etched. In step S4, the patterned first Au interdigital electrode (6) is prepared on both sides of the first Pt resistance (4) along the length direction of the silicon substrate (1), and the patterned second Au interdigital electrode (10) is prepared on the upper surface of the third Si3N4thin film (9). In step S5, the first Si3N4thin film (3) is deposited on the lower surface of the silicon substrate (1), and the first Si3N4thin film (3) is scribed at both ends along the length direction of the silicon substrate (1). In step S6, the patterned second Pt resistance (7) is prepared on the lower surface of the first Si3N4thin film (3), and the PI thin film (11) is prepared on the upper surface of the second Au interdigital electrode (10) by spin coating, followed by wire bonding and packaging to obtain the salt mist environment parameter detection micro-nano sensor.

5. The method for fabricating a micro / nano sensor for detecting salt spray environmental parameters according to claim 4, characterized in that, In step S2, the silicon substrate (1) is first dry-oxygen oxidized at 1100℃ for 50min, and then wet-oxygen oxidized for 450min to obtain a uniform SiO2insulating layer (2) with a thickness of 2um on both sides, and the SiO2insulating layer (2) on the lower surface of the silicon substrate (1) is removed by wet etching with a BOE solution.

6. The method for fabricating a micro / nano sensor for detecting salt spray environmental parameters according to claim 4, characterized in that, In step S2, the upper surface of the SiO2insulating layer (2) is sequentially coated with glue, pre-baked, photoetched, developed, and post-baked after development to prepare a patterned first photoresist mask, then a layer of Cr is sputtered on the upper surface of the first photoresist mask as an adhesion layer, and a layer of 50 / 200nm Pt metal layer is sputtered, and based on the photoetching pattern on the first photoresist mask, the Pt metal layer is etched by lift-off process to obtain the first Pt resistance (4) and the third Pt resistance (8).

7. The method for fabricating a micro / nano sensor for detecting salt spray environmental parameters according to claim 4, characterized in that, In step S3, a layer of 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 then the upper surface of the Si3N4 film (12) is coated with glue, pre-baked, photoetched, developed, and post-baked to prepare a patterned second photoresist mask. Then, the Si3N4 film (12) is etched by using a reactive ion etching process based on the photoetching pattern on the second photoresist mask to obtain the second Si3N4 film (5) and the third Si3N4 film (9).

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

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

10. A measurement method of a salt spray environment parameter detection micro-nano sensor, applied to the salt spray environment parameter detection micro-nano sensor according to any one of claims 1-3, comprising the following steps: Step A1, placing the salt spray environment parameter detection micro-nano sensor and a hygrometer in a salt spray test chamber to measure the temperature and humidity in the salt spray test chamber; Step A2, continuously spraying a neutral salt spray solution on the salt spray environment parameter detection micro-nano sensor while keeping the temperature in the salt spray test chamber unchanged, and monitoring the resistance value change of the first Pt resistor (4) and the second Pt resistor (7), the current and voltage change between the two first Au interdigital electrodes (6), and the capacitance change of the second Au interdigital electrode (10) and the current temperature and humidity, and adding them to the monitoring data; Step A3, keeping the temperature in the salt spray test chamber unchanged to control the humidity or keeping the humidity in the salt spray test chamber unchanged to control the temperature, and obtaining the relationship between temperature and humidity and conductivity change and surface liquid film wetting time according to the monitoring data. Step A4, based on the relationship, by temperature and humidity calibration and conductivity calculation formula σ = K / R S and the relationship between the capacitance and the dielectric constant C = nεlh / Ws + nε / 2, the corresponding temperature and humidity, wet time and conductivity parameters are obtained.

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