A micro-nano thin film temperature sensor based on a metal substrate and a manufacturing method thereof

Abstract

The present invention relates to a micro-nano thin film temperature sensor based on a metal substrate and a manufacturing method thereof, belonging to the technical field of micro-nano sensors. The micro-nano thin film temperature sensor comprises a metal substrate, a metal transition layer, a metal bonding layer, an insulating layer, a first-pole metal sensing layer, a second-pole metal sensing layer, a protective layer and a lead wire. The manufacturing method is as follows: 1) depositing a metal transition layer on the metal substrate; 2) depositing a metal bonding layer on the surface of the metal transition layer; 3) coating an insulating layer on the surface of the metal bonding layer; 4) manufacturing the first-pole metal sensing layer and the second-pole metal sensing layer; 5) cutting the protective layer according to the size of the sensor, and sequentially depositing a metal transition layer and a metal bonding layer on the bottom surface of the protective layer; The present invention has little interference on the original temperature field, can accurately capture the dynamic changes of the temperature field, can be flexibly installed in a narrow space and closer to the measurement point for detection, and multiple groups of thermocouples can be arranged at a single measurement point simultaneously according to requirements to achieve local multi-point detection.

Description

Technical Field

[0001] The invention belongs to the technical field of micro-nano sensors and relates to a micro-nano thin film temperature sensor based on a metal substrate and a manufacturing method thereof. Background Art

[0002] Temperature detection is a task that is often carried out in the process of modern industrial production and scientific research. Traditional armored thermocouples or thermal resistors are often difficult to use in some scenarios with strict installation space size restrictions and more drastic instantaneous dynamic changes due to their large size and slow response. Even if they can be used, their performance will be greatly reduced in terms of accuracy, reliability, timeliness and durability. Armored thermal resistor is a temperature sensor that measures temperature by using the characteristic that the resistance of a material changes as the temperature changes. When the resistance changes, the working instrument displays the temperature value corresponding to the resistance. It has a smaller diameter than the assembled platinum resistor and is easy to bend. It is suitable for installation in special occasions such as narrow pipes and requiring fast response and miniaturization. It can automatically detect gas, liquid media and solid surfaces in the temperature range of -200 to 600 ° C, and can be directly connected to the secondary instrument with copper wire. Because it has good electrical output characteristics, it can provide accurate input values for displays, recorders, regulators, scanners, data recorders and computers. The armored thermal resistor is a temperature sensing element with a ceramic or glass frame installed in a thin stainless steel tube, which is firmly filled with magnesium oxide to ensure good insulation between its three wires and the protective tube, as well as between the wires. After sufficient drying, the ends are sealed and then drawn into a solid whole through a mold, which is called an armored thermal resistor.

[0003] Armored thermocouples also have the following disadvantages:

[0004] 1. The signal conditioning is more complicated. When converting the voltage of the thermocouple into a usable temperature reading, a lot of signal conditioning is required. In fact, signal conditioning takes a lot of time. If it is not handled properly, serious errors will occur, which will eventually lead to reduced accuracy.

[0005] Second, it is easy to be corroded. Since the thermocouple is composed of two completely different metals, in some cases, it will be corroded over time, thus affecting its accuracy. Therefore, it is necessary to properly protect the thermocouple, and maintenance and care are also necessary;

[0006] 3. The accuracy is relatively low. The characteristics of metal are the reason why the accuracy of thermocouples is unstable. The accuracy of thermocouples in measurement is still based on the accuracy of the temperature at the junction.

[0007] Fourth, the anti-noise performance is relatively poor. When the millivolt level measured changes in the signal, noise may appear in the magnetic field and electric field. Summary of the Invention

[0008] In view of this, the purpose of the present invention is to provide a micro-nano thin film temperature sensor based on a metal substrate and a manufacturing method thereof.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] A micro-nano thin film temperature sensor based on a metal substrate includes a metal substrate 3, a metal transition layer 4, a metal bonding layer 5, an insulating layer 6, a first-pole metal sensing layer, a second-pole metal sensing layer, a protective layer, and a wire;

[0011] A metal transition layer is deposited on the metal substrate;

[0012] A metal bonding layer and an insulating layer are sequentially deposited on the metal transition layer;

[0013] A metal bonding layer and a first-pole metal sensing layer are sequentially deposited on the insulating layer;

[0014] A number of thermoelectric couple circuits are integrated on the first-pole metal sensing layer;

[0015] A sensor pad 10 for connecting a wire is provided on the first-pole metal sensing layer;

[0016] A metal bonding layer and a second-pole metal sensing layer are sequentially deposited on the first-pole metal sensing layer;

[0017] A number of thermoelectric couple circuits are integrated on the second-pole metal sensing layer;

[0018] A sensor pad for connecting a wire is provided on the second-pole metal sensing layer;

[0019] A metal bonding layer, a metal transition layer, and a protective layer are sequentially deposited on the second-pole metal sensing layer;

[0020] One end of the wire is connected to the sensor pad, and the other end is connected to the sensor temperature sensing end 11.

[0021] Optionally, the thickness range of the metal transition layer is [5 μm, 30 μm], the thickness range of the metal bonding layer is [10 nm, 100 nm], the thickness range of the insulating layer is [1 μm, 5 μm], and the thickness range of the metal sensing layer 8 is [300 nm, 900 nm].

[0022] Optionally, the deposition includes electroplating, spin coating, photolithography, and magnetron sputtering.

[0023] Optionally, the materials of the two poles of the thermocouple circuit include one or more of NiCr-NiAlMnSi alloy, NiCr-NiAl alloy, and NiCr-NiSi alloy.

[0024] Optionally, the material of the insulating layer is polyimide;

[0025] The material of the metal bonding layer is metal titanium;

[0026] The materials of the first-pole metal sensing layer and the second-pole metal sensing layer are nickel-based alloys;

[0027] The material of the protective layer is copper;

[0028] The material of the wire is conductive silver paste.

[0029] Optionally, the material of the insulating layer is an oxide;

[0030] The material of the metal bonding layer is metal titanium;

[0031] The materials of the first-pole metal sensing layer and the second-pole metal sensing layer are nickel-based alloys;

[0032] The material of the protective layer is copper;

[0033] The material of the wire is conductive silver paste.

[0034] Optionally, the sensor pads are exposed.

[0035] Based on the manufacturing method of the micro-nano thin film temperature sensor, the manufacturing method includes the following steps:

[0036] S11: Based on the temperature detection range, design the shape, size, and quantity of the sensor, and manufacture the mask plate of the micro-nano thin film temperature sensor;

[0037] S12: Select the metal substrate of the micro-nano thin film temperature sensor;

[0038] S13: Deposit a metal transition layer on the metal substrate;

[0039] S14: Use the magnetron sputtering process to deposit a metal bonding layer on the surface of the metal transition layer;

[0040] S15: Use the spin coating process to coat an insulating layer on the surface of the metal bonding layer;

[0041] S16: Soft bake the metal substrate deposited with the metal transition layer, metal bonding layer, and insulating layer on a hot plate; after soft baking, cure the metal substrate in an oven;

[0042] S17: Apply a layer of photoresist with a thickness ranging from [1 μm, 5 μm] on the surface of the insulating layer using the spin coating process, and perform pre-baking on a hot plate; use a mask on the lithography machine to expose the pre-baked metal substrate; after exposure, place the metal substrate on the hot plate for post-baking, and then place it in the developer for development;

[0043] S18: Use the magnetron sputtering process to sequentially deposit a metal bonding layer, a first-pole metal sensing layer, a second-pole metal sensing layer, and a metal bonding layer on the surface of the photoresist layer;

[0044] S19: Immerse the metal substrate in acetone for soaking and peeling; after peeling, clean and dry the metal substrate to form the first-pole metal sensing layer; the first-pole metal sensing layer has a sensor pad connected to a wire;

[0045] S110: Apply a layer of photoresist with a thickness ranging from [1 μm, 5 μm] on the surface of the first-pole metal sensing layer, and perform pre-baking on a hot plate; use a mask on the lithography machine to expose the pre-baked metal substrate; after exposure, place the metal substrate on the hot plate for post-baking, and then place it in the developer for development;

[0046] S111: Repeat steps S18 and S19 to fabricate the second-pole metal sensing layer; the second-pole metal sensing layer has a sensor pad connected to a wire;

[0047] S112: Cut the protective layer based on the sensor size, and sequentially deposit a metal transition layer and a metal bonding layer on the bottom surface of the protective layer;

[0048] S113: Deposit an insulating layer on the second-pole metal sensing layer, and bond the protective layer to the insulating layer to form the micro-nano thin film temperature sensor to be encapsulated; the protective layer does not cover the sensor pads of the first-pole metal sensing layer and the second-pole metal sensing layer;

[0049] S114: Bake and cure the micro-nano thin film temperature sensor to be encapsulated to form a sandwich-layered encapsulation structure;

[0050] S115: Use the plasma etching process to remove the insulating layer on the surface of the sensor pads;

[0051] S116: Connect wires to the sensor pads, and use a hot plate for baking and curing; after baking and curing, apply a layer of epoxy resin on the sensor pads and cure for a time t to form the micro-nano thin film temperature sensor; t > 0.

[0052] Optionally, the time t = [10 h, 36 h].

[0053] Based on the manufacturing method of the micro-nano film temperature sensor, the manufacturing method includes the following steps:

[0054] S21: Use metal as the substrate of the sensor to form a metal substrate;

[0055] S22: Deposit a metal transition layer, a metal bonding layer, an insulating layer, a first-pole metal sensing layer, a second-pole metal sensing layer, and a protective layer layer by layer on the metal substrate through electroplating, spin coating, photolithography, and magnetron sputtering processes to form a sandwich-like layered structure;

[0056] Sputter a layer of metal titanium on the surface of the metal transition layer as the metal bonding layer to effectively enhance the bonding between the metal substrate and the insulating layer; Sputter a layer of metal titanium on the upper and lower sides of the sensor metal sensing layer as the metal bonding layer to effectively enhance the bonding between the metal sensing layer and the insulating layer;

[0057] S23: Deposit multiple sets of thermocouple circuits simultaneously on the metal sensing layer of the same substrate to achieve multi-point detection in a local area;

[0058] S24: Use a two-component conductive silver paste as the wire connection material for the sensor pads.

[0059] Optionally, the thickness of the metal transition layer is 5 - 30 μm, the thickness of the metal bonding layer is 10 - 100 nm, the thickness of the insulating layer is 1 - 5 μm, and the thickness of the metal sensing layer is 300 - 900 nm;

[0060] Optionally, the metal is copper or chromium zirconium copper.

[0061] Optionally, in S22, the sensor uses a metal copper, chromium zirconium copper, or tungsten with good electrical conductivity and thermal conductivity as the protective layer;

[0062] The sensor uses polyimide as the insulating layer to achieve temperature detection in an environment of 400 °C;

[0063] Electroplate a layer of metal nickel similar to it and having good thermal conductivity, electrical conductivity, and strength on the substrate as the metal transition layer;

[0064] Sputter a layer of metal on the upper and lower sides of the alloy material of the metal sensing layer as the metal bonding layer to enhance the bonding between the metal sensing layer and the insulating layer and prevent delamination;

[0065] The sensor pads use a high-temperature-resistant conductive bonding material, conductive silver paste, as the wire connection material.

[0066] Optionally, in S23, the sensor is designed based on the principle of K-type thermocouple, and one or more of NiCr-NiAlMnSi alloy, NiCr-NiAl alloy, and NiCr-NiSi alloy are used as the two pole materials constituting the thermoelectric couple loop.

[0067] Based on the manufacturing method of the micro-nano thin film temperature sensor, the manufacturing method includes the following steps:

[0068] S31: According to the requirements of temperature detection, design and manufacture a mask plate for the micro-nano thin film temperature sensor, including the shape, size, and quantity of the sensor;

[0069] S32: Use a 4-inch diameter and 800-μm thick metal as the substrate for sensor deposition. After polishing the copper sheet, deposit a 5-30-μm thick metal transition layer on its surface;

[0070] S33: Deposit a 10-100-nm thick metal titanium layer on the surface of the metal transition layer through magnetron sputtering;

[0071] S34: Coat a 1-5-μm thick organic polymer material, polyimide, on the surface of the titanium layer through spin coating, and perform soft baking and curing in a hot plate and an oven respectively;

[0072] S35: Coat a 1-5-μm thick photoresist on the surface of the insulating layer through spin coating, perform pre-baking on a hot plate, then use the mask plate for exposure on a photolithography machine, perform post-baking on the hot plate after completion, and then place it in a developer for development. After cleaning and drying, form a plate with the shape and size of the sensor;

[0073] S36: Deposit three layers of metals on the surface of the photoresist layer through magnetron sputtering in sequence, namely a 10-100-nm thick metal titanium, a 300-900-nm thick nickel-based alloy, and a 10-100-nm thick metal titanium, then soak it in acetone for soaking and peeling, and after cleaning and drying, form the first pole sensing loop;

[0074] S37: Repeat the two process steps of S35 and S36. After coating a new 1-5-μm thick photoresist and performing exposure and development, deposit metal titanium, the other pole nickel-based alloy, and metal titanium in sequence, and form the second pole sensing loop;

[0075] S38: Cut the protective layer metal sheet in a crown shape according to the size characteristics of the sensor, and deposit the metal transition layer and the metal bonding layer in sequence through electroplating and magnetron sputtering processes;

[0076] S39: Apply a layer of polyimide with a thickness of 1 - 5 μm onto the completed metal sensing layer through a spin coating process. Use its adhesiveness to bond the copper sheet processed in the previous step onto the substrate wafer, exactly exposing the pad area. Then, perform baking and curing to form a sandwich - layer packaging structure. Finally, remove the insulating layer on the pad surface through a plasma etching process to expose the pads for wire connection;

[0077] S310: Connect the compensation wires to all the pads on the metal sensing layer with conductive silver glue. After baking and curing on a hot plate, apply a layer of epoxy resin. Then, complete the fabrication of the sensor after 10 - 36 hours of aging and curing. It detects temperature by collecting potential signals, and the metal sensing layer is its core working layer.

[0078] Based on the manufacturing method of the micro - nano thin - film temperature sensor, the manufacturing method includes the following steps:

[0079] S41: First, according to the requirements of temperature detection, design the micro - nano thin - film temperature sensor, including the shape, size, and quantity of the sensor. The design of the sensor is based on the Seebeck effect thermoelectric principle, that is: two different conductors are used as the sensor anode 1 and sensor cathode 2 respectively, and their two joints are connected together to form a closed loop. When the temperatures of the two joints are not equal, with the hot - end temperature T > the cold - end temperature T0, an electromotive force will be generated in the loop, thus forming a thermal current. When the cold - end temperature T0 is fixed, the thermoelectric potential is a single - valued function of the hot - end temperature T. Calculate the specific value of the hot - end temperature T according to the magnitude of the generated thermoelectric potential. The sensor uses a K - type thermocouple and selects a K - type thermocouple alloy as the metal sensing layer. Arrange multiple groups of sensors on the substrate wafer according to requirements, and arrange multiple pairs of thermoelectric couple loops in each group of sensors. When considering the planar size of the sensor, the success rate of sensor fabrication should also be taken into account, that is, the line - width size of a single electrode and the distance between each pair of electrodes should not be too small (≥5 μm). In addition, to reduce the difficulty of wire connection and ensure insulation between each pair of pads, the side - length size of a single square pad and the distance between each pair of pads should not be too small (≥3 mm);

[0080] S42: Use a 4 - inch - diameter, 800 - μm - thick metal copper sheet as the substrate wafer for sensor deposition and select it as the protective layer. After the copper sheet is polished and ground, perform pre - treatment such as cleaning the substrate wafer and depositing a metal transition layer;

[0081] S43: To enhance the bonding between the metal substrate wafer and the subsequent insulating layer, deposit a 10 - 100 - nm - thick metal titanium layer as a metal bonding layer on the surface of the metal transition layer through a magnetron sputtering process. If the surface of the substrate wafer is rough, increase the deposition thickness;

[0082] S44: Fabricate the insulating layer. Spin-coat a layer of polyimide on the surface of the titanium layer through the spin-coating process of photoresist, and perform spin-coating on the substrate wafer using a spin coater; then, perform soft baking on a hot plate; next, perform baking and curing in an oven; Considering the comprehensive factors of good thermal conductivity and insulating protection, it is more appropriate to control the thickness of the insulating layer to be 0.5 - 5 μm after baking and curing;

[0083] S45: To fabricate the designed sensor layout for the next sputter deposition of the metal sensing layer, next, spin-coat a layer of photoresist with a thickness of 1 - 5 μm on the surface of the insulating layer; perform pre-baking on a hot plate to remove the solvent in the photoresist and enhance adhesion; place the pre-baked substrate wafer on a lithography machine for exposure; after exposure, place the substrate wafer on a hot plate for post-baking to stimulate the acid generated by the PAG photosensitive acid generator in the chemically amplified photoresist to react with the protecting groups on the photoresist and remove the groups so that it can dissolve in the developer, and at the same time reduce the standing wave effect; place the post-baked substrate wafer in the developer for development, after development is completed, perform cleaning with deionized water, and blow dry with nitrogen, finally forming a layout with the shape and size of the sensor;

[0084] S46: Fabricate the metal sensing layer; sputter a layer of metal titanium with a thickness of 10 - 100 nm according to the process method in S43; then magnetron sputter deposit a layer of nickel-based alloy with a thickness of 300 - 900 nm, and then sputter a layer of metal titanium with a thickness of 10 - 100 nm according to the process method in S43; after deposition is completed, take out the substrate wafer and soak it in acetone for the soaking and stripping process to remove the remaining photoresist on the substrate wafer, perform cleaning with deionized water, and blow dry with nitrogen, and complete the deposition of the first-pole sensing loop on the substrate wafer;

[0085] S47: Repeat the two process steps of S45 and S46. First, spin-coat a layer of photoresist with a thickness of 1 - 5 μm; then sputter deposit a layer of metal titanium with a thickness of 10 - 100 nm; then sputter deposit a layer of nickel-based alloy with a thickness of 300 - 900 nm for the other pole, and then sputter deposit a layer of metal titanium with a thickness of 10 - 100 nm; after deposition is completed, through soaking and stripping, cleaning and drying, complete the deposition of the second-pole sensing loop on the substrate wafer, and complete the fabrication of the metal sensing layer;

[0086] S48: To prevent the thin-film sensor from being worn and eroded in a harsh environment, perform encapsulation protection on it; first, cut a copper sheet in a crown shape according to the size characteristics of the sensor, and then also use the electroplating process and the magnetron sputtering process to sequentially deposit a layer of metal transition layer metal with a thickness of 5 - 30 μm and a layer of metal bonding layer metal titanium with a thickness of 10 - 100 nm on the surface of the copper sheet;

[0087] S49: Apply a layer of polyimide with a thickness of 1 - 5 μm on the fabricated metal sensing layer through a spin coating process. Use its adhesiveness to attach the copper sheet prepared in the previous step to the substrate, exposing the pad area. Then bake and cure it in an oven to form a sandwich - layer packaging structure. Finally, remove the insulating layer on the pad surface through a plasma etching process to expose the pads for wiring.

[0088] S410: Use conductive silver paste to connect all pads on the metal sensing layer to compensation wires with a diameter of 0.2 - 0.5 mm. After baking on a hot plate, apply a layer of epoxy resin for covering to reduce the influence of external forces on the connection part between the wire and the pad and prevent the wire from disconnecting. After aging and curing for 10 - 36 hours, complete the production of the entire sensor, and detect the temperature by collecting potential signals.

[0089] Optionally, the sputtering is to bombard the surface of a solid target with a plasma having a kinetic energy of more than dozens of electron volts. Atoms near the surface obtain part of the energy carried by the incident particles. When the energy is sufficient to overcome the binding energy, these atoms will break away from the solid and enter the vacuum chamber, and then deposit on the substrate.

[0090] Optionally, in S43, the process parameters of sputtering are: sputtering power 200 - 600 W, sputtering rate 10 - 20 nm / min, and sputtering time 2 - 6 min.

[0091] Optionally, in S46, the process parameters of sputtering are: sputtering power 200 - 600 W, sputtering rate 10 - 20 nm / min, and sputtering time 30 - 80 min.

[0092] Optionally, in S47, the process parameters of sputtering are: sputtering power 200 - 600 W, sputtering rate 10 - 20 nm / min, and sputtering time 30 - 80 min.

[0093] The beneficial effects of the present invention are as follows:

[0094] The present invention is applicable to local multi - point dynamic temperature detection in a high - temperature environment of 400 °C. Compared with traditional filament thermocouples, it has significant technical characteristics such as small size, fast response, high precision, and good protection. It is particularly suitable for detection scenarios with strict installation size limitations and drastic changes in transient temperature fields, and can be widely applied in fields such as aerospace, precision machine tool processing, national defense, and metallurgical manufacturing.

[0095] It should be noted that the design of the metal sensing layer fabricated in the present invention is based on the principle of K-type thermocouple. Two different nickel-based alloys are used as the two pole materials constituting the thermoelectric couple loop, and the hot-end temperature value of the detection point is obtained by reading the thermoelectric emf signal. Multiple groups of thermoelectric couple loops can be simultaneously deposited on the metal sensing layer of the same substrate wafer to achieve multi-point detection in a narrow local area, with a relatively high spatial resolution. Moreover, even if one detection point is damaged, the remaining other detection points can still work normally, and the detection redundancy is good. The sensor film thickness is only several hundred nanometers, the line width and the size of the thermal junction are small, the mass and the heat capacity are small, and it responds rapidly to the rapid change of the temperature field. Its response time can reach the microsecond level, and the interference and damage to the real temperature field of the detection point are relatively small.

[0096] The micro-nano thin film sensor based on a metal substrate proposed in the present invention is small in size and fast in response, has less interference to the original temperature field, can capture the instantaneous dynamic change of the temperature field in a timely and accurate manner, can be flexibly and conveniently installed in a narrow space and closer to the point to be measured for detection, and multiple groups of thermoelectric couple loops can be arranged at one detection point according to requirements to achieve local multi-point detection. The sandwich-layer packaging structure based on the metal copper substrate with relatively high melting point and hardness and good thermal and electrical conductivity enables the sensor to have good high-temperature and high-pressure resistance and anti-interference performance, can effectively avoid abrasion and erosion, can effectively guarantee the use effect of the thin film sensor in a harsh industrial environment, and helps to greatly improve its durability and service life. The present invention can significantly improve the technical limitations and drawbacks of traditional temperature detection elements in terms of spatial size, dynamic response, packaging protection, etc., provides an important hardware basis and technical means for the optimization and innovation of traditional temperature measurement methods, and is worthy of popularization and application in various temperature detection fields.

[0097] Other advantages, objectives and features of the present invention will be described to some extent in the subsequent specification, and to some extent, will be obvious to those skilled in the art based on the study of the following text, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0098] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be described in detail preferably with reference to the accompanying drawings, wherein:

[0099] Figure 1 is a schematic design diagram of the micro-nano thin film temperature sensor;

[0100] Figure 2 is a schematic structural diagram of the substrate wafer after electroplating nickel;

[0101] Figure 3 is a schematic structural diagram of the substrate wafer after sputtering titanium;

[0102] Figure 4 Schematic diagram of the structure after spin - coating polyimide on the substrate

[0103] Figure 5 Schematic diagram of the exposure & development process steps

[0104] Figure 6 Schematic diagram of sputtering deposition of the metal sensing layer

[0105] Figure 7 Schematic diagram after completing the deposition of the two - pole sensing circuit

[0106] Figure 8 Schematic diagram of the sandwich - layer packaging structure after completing RIE etching

[0107] Figure 9 Schematic diagram of the core working layer of the micro - nano thin - film temperature sensor

[0108] Figure 10 Schematic diagram of the metal sheet required for sensor packaging

[0109] Reference numerals: 1 - sensor anode, 2 - sensor cathode, 3 - metal substrate, 4 - metal transition layer, 5 - metal bonding layer, 6 - insulating layer, 7 - photoresist, 8 - metal sensing layer, 9 - wire, 10 - sensor pad, 11 - sensor temperature - sensing end. Detailed implementation manners

[0110] The following illustrates the implementation manners of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the drawings provided in the following examples only illustrate the basic concept of the present invention schematically. Without conflict, the following examples and the features in the examples can be combined with each other.

[0111] Among them, the drawings are only for illustrative purposes, showing only schematic diagrams, not physical diagrams, and should not be construed as a limitation to the present invention; for better illustrating the embodiments of the present invention, some components in the drawings will be omitted, enlarged or reduced, which do not represent the dimensions of the actual product; for those skilled in the art, it is understandable that some well - known structures and their descriptions in the drawings may be omitted.

[0112] In the drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "rear", etc. indicating the orientation or positional relationship, it is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only for illustrative purposes and cannot be construed as a limitation of the present invention. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0113] Embodiment 1:

[0114] A micro-nano thin film temperature sensor based on a metal substrate mainly includes a metal substrate 3, a metal transition layer 4, a metal bonding layer 5, an insulating layer 6, a first-pole metal sensing layer, a second-pole metal sensing layer, a protective layer, and a wire 9.

[0115] A metal transition layer is deposited on the metal substrate.

[0116] Furthermore, the deposition methods mainly include electroplating, spin coating, photolithography, and magnetron sputtering.

[0117] A metal bonding layer and an insulating layer are sequentially deposited on the metal transition layer.

[0118] A metal bonding layer and a first-pole metal sensing layer are sequentially deposited on the insulating layer.

[0119] Furthermore, the material of the insulating layer is polyimide.

[0120] The material of the metal bonding layer is titanium.

[0121] The materials of the first-pole metal sensing layer and the second-pole metal sensing layer are nickel-based alloys.

[0122] A number of thermoelectric couple circuits are integrated on the first-pole metal sensing layer.

[0123] A sensor pad 10 for connecting a wire is provided on the first-pole metal sensing layer.

[0124] Furthermore, the sensor pad is exposed.

[0125] A metal bonding layer and a second-pole metal sensing layer are sequentially deposited on the first-pole metal sensing layer.

[0126] A number of thermoelectric couple circuits are integrated on the second-pole metal sensing layer.

[0127] Further, the two-pole materials of the thermocouple loop include NiCr—NiAlMnSi, NiCr—NiAl, and / or NiCr—NiSi alloys.

[0128] A sensor pad for connecting a wire is provided on the second-pole metal sensing layer.

[0129] A metal bonding layer, a metal transition layer, and a protective layer are sequentially deposited on the second-pole metal sensing layer.

[0130] The material of the protective layer is copper.

[0131] One end of the wire is connected to the sensor pad, and the other end is connected to the temperature-sensing end 11 of the sensor.

[0132] Further, the material of the wire is conductive silver paste.

[0133] Further, the thickness range of the metal transition layer is [5 μm, 30 μm], the thickness range of the metal bonding layer is [10 nm, 100 nm], the thickness range of the insulating layer is [1 μm, 5 μm], and the thickness range of the metal sensing layer 8 is [300 nm, 900 nm].

[0134] Example 2:

[0135] A manufacturing method of a micro-nano thin-film temperature sensor based on a metal substrate mainly includes the following steps:

[0136] 1) Based on the temperature detection range, design the shape, size, and quantity of the sensor, and manufacture a mask plate for the micro-nano thin-film temperature sensor.

[0137] 2) Select a metal substrate for the micro-nano thin-film temperature sensor.

[0138] 3) Deposit a metal transition layer on the metal substrate.

[0139] 4) Use a magnetron sputtering process to deposit a metal bonding layer on the surface of the metal transition layer.

[0140] 5) Use a spin coating process to coat an insulating layer on the surface of the metal bonding layer.

[0141] 6) Soft bake the metal substrate deposited with the metal transition layer, the metal bonding layer, and the insulating layer on a hot plate. After soft baking, cure the metal substrate in an oven.

[0142] 7) Use a spin coating process to coat a photoresist 7 with a thickness range of [1 μm, 5 μm] on the surface of the insulating layer, and perform pre-baking on a hot plate.

[0143] On the lithography machine, a mask is used to expose the metal substrate after pre-baking. After exposure, the metal substrate is placed on a hot plate for post-baking, and then placed in a developer for development.

[0144] 8) Use the magnetron sputtering process to sequentially deposit a metal bonding layer, a metal sensing layer, and a metal bonding layer on the surface of the photoresist layer.

[0145] 9) Immerse the metal substrate in acetone for soaking and stripping. After stripping, clean and dry the metal substrate to form the first-pole metal sensing layer, that is, the first-pole sensing circuit. The first-pole metal sensing layer has a sensor pad connected to a wire.

[0146] 10) Coat a layer of photoresist with a thickness range of [1 μm, 5 μm] on the surface of the first-pole metal sensing layer and perform pre-baking on a hot plate.

[0147] On the lithography machine, a mask is used to expose the metal substrate after pre-baking. After exposure, the metal substrate is placed on a hot plate for post-baking, and then placed in a developer for development.

[0148] 11) Repeat steps 8) to 9) to fabricate the second-pole metal sensing layer, that is, the second-pole sensing circuit. The second-pole metal sensing layer has a sensor pad connected to a wire.

[0149] 12) Cut the protective layer according to the sensor size, and sequentially deposit a metal transition layer and a metal bonding layer on the bottom surface of the protective layer.

[0150] 13) Deposit an insulating layer on the second-pole metal sensing layer and bond the protective layer to the insulating layer to form the micro-nano thin film temperature sensor to be encapsulated. The protective layer does not cover the sensor pads of the first-pole metal sensing layer and the second-pole metal sensing layer.

[0151] 14) Bake and cure the micro-nano thin film temperature sensor to be encapsulated to form a sandwich-layered encapsulation structure.

[0152] 15) Use the plasma etching process to remove the insulating layer on the surface of the sensor pad.

[0153] 16) Connect the wire to the sensor pad and use a hot plate for baking and curing. After baking and curing, apply a layer of epoxy resin on the sensor pad and cure for t hours to form the micro-nano thin film temperature sensor. t > 0.

[0154] t = [10 h, 36 h].

[0155] Example 3:

[0156] A manufacturing method of a micro-nano thin film temperature sensor based on a metal substrate mainly includes the following steps:

[0157] 1) Use metal as the substrate of the sensor, that is, the metal base.

[0158] Furthermore, use a metal with good electrical conductivity and thermal conductivity, and relatively high melting point and hardness as the substrate for sensor fabrication.

[0159] 2) Deposit the metal transition layer, metal bonding layer, insulating layer, metal sensing layer, and protective layer layer by layer on the metal base through processes such as electroplating, spin coating, photolithography, and magnetron sputtering to form a typical sandwich-like layered structure.

[0160] Among them, the sensor uses a metal with good electrical conductivity and thermal conductivity as the protective layer, and uses a polymer insulating material with good thermal stability and mechanical properties as the insulating layer, which can reliably achieve temperature detection in an environment of 400 °C; electroplate a layer of metal similar to it and with good thermal conductivity, electrical conductivity, and strength on the substrate as the metal transition layer; sputter a layer of metal on both the upper and lower sides of the metal sensing layer alloy material as the metal bonding layer to effectively enhance the bonding between the metal sensing layer and the insulating layer and prevent delamination; the sensor pad uses a conductive bonding material that can withstand high temperatures as the wire connection material, which can ensure the reliability and stability of the sensor in a long-term high-temperature environment. The sensor uses polyimide with good thermal stability and mechanical properties as the insulating layer, which can reliably achieve temperature detection in an environment of 400 °C.

[0161] Sputter a layer of metal titanium on the surface of the metal transition layer as the metal bonding layer to effectively enhance the bonding between the metal substrate and the insulating layer.

[0162] Sputter a layer of metal titanium on both the upper and lower sides of the sensor metal sensing layer as the metal bonding layer to effectively enhance the bonding between the metal sensing layer and the insulating layer.

[0163] The thickness of the metal transition layer is 5 - 30 μm, the thickness of the metal bonding layer is 10 - 100 nm, the thickness of the insulating layer is 1 - 5 μm, and the thickness of the metal sensing layer is 300 - 900 nm.

[0164] 3) Deposit multiple sets of thermocouple circuits simultaneously on the metal sensing layer of the same substrate to achieve multi-point detection in a narrow local area.

[0165] Furthermore, the design of the sensor is based on the K-type thermocouple principle, and uses NiCr—NiAlMnSi, NiCr—NiAl, and NiCr—NiSi alloys as the two-pole materials for forming the thermocouple circuit.

[0166] 4) The sensor pad uses a two-component conductive silver glue as the wire connection material, which can ensure the reliability and stability of the sensor in a long-term high-temperature environment.

[0167] Example 4:

[0168] Based on the classical Seebeck effect and the principle of K-type thermocouple, in a clean room, through MEMS microelectromechanical processing technologies such as spin coating, photolithography and development, and magnetron sputtering, using a metal with relatively high melting point and hardness and good thermal and electrical conductivity as the substrate, a micro-nano thin film temperature sensor with a typical sandwich-layered packaging structure that can withstand high temperatures of 400 °C is fabricated. The fabrication method mainly includes the following steps:

[0169] 1) According to the requirements of temperature detection, design and fabricate a mask for the micro-nano thin film temperature sensor, including the shape, size and quantity of the sensor, as shown in Figure 1 shown.

[0170] 2) Use a 4-inch-diameter, 800-μm-thick metal as the substrate for sensor deposition. After polishing the copper sheet, deposit a metal transition layer with a thickness of 5 - 30 μm on the surface, as shown in Figure 2 shown.

[0171] 3) Deposit a 10 - 100-nm-thick metal titanium layer on the surface of the metal transition layer through magnetron sputtering, as shown in Figure 3 shown.

[0172] 4) Coat a 1 - 5-μm-thick organic polymer material, polyimide, on the surface of the titanium layer through spin coating, and perform soft baking and curing in a hot plate and an oven respectively, as shown in Figure 4 shown.

[0173] 5) Coat a 1 - 5-μm-thick photoresist on the surface of the insulating layer through spin coating, perform pre-baking on a hot plate, then use the mask for exposure on a lithography machine, after completion, place it on the hot plate for post-baking, and then place it in a developer for development. After cleaning and drying, a plate with the shape and size of the sensor will be formed, as shown in Figure 5 shown.

[0174] 6) Deposit three layers of metals on the surface of the photoresist layer through magnetron sputtering in sequence, namely a 10 - 100-nm-thick metal titanium, a 300 - 900-nm-thick nickel-based alloy, and a 10 - 100-nm-thick metal titanium. Then place it in acetone for immersion and stripping, and after cleaning and drying, form the first-pole sensing circuit, as shown in Figure 6 shown.

[0175] 7) Repeat the above two process steps, coat a new 1 - 5-μm-thick photoresist, after exposure and development, deposit metal titanium, the other-pole nickel-based alloy, and metal titanium in sequence, and form the second-pole sensing circuit, as shown in Figure 7 shown.

[0176] 8) Cut the protective layer metal sheet in a crown shape according to the characteristics of the sensor size, and also use the electroplating process and the magnetron sputtering process to sequentially deposit the metal transition layer and the metal bonding layer respectively.

[0177] 9) Apply a layer of polyimide with a thickness of 1 - 5 μm on the fabricated metal sensing layer through the spin coating process. Use its adhesiveness to bond the copper sheet processed in the previous step to the substrate, just exposing the pad part. Then bake and cure it to form a sandwich - layer packaging structure. Finally, remove the insulating layer on the pad surface through the plasma etching process to expose the pads for wires, as shown in Figure 8 shown.

[0178] 10) Connect the compensation wires to all the pads on the metal sensing layer with conductive silver glue. After baking and curing on a hot plate, apply a layer of epoxy resin. After aging and curing for 10 - 36 hours, the production of the entire sensor is completed. It detects temperature by collecting the potential signal, and the metal sensing layer is its core working layer, as shown in Figure 9 shown.

[0179] Example 5:

[0180] A manufacturing method of a micro - nano thin - film temperature sensor based on a metal substrate mainly includes the following steps:

[0181] 1) First, according to the requirements of temperature detection, design a micro - nano thin - film temperature sensor, as shown in Figure 1 shown, which includes the shape, size, and quantity of the sensor. The design of the sensor is based on the Seebeck effect thermoelectric principle, that is: two different conductors are used as the sensor anode 1 and the sensor cathode 2 respectively, and their two ends are tightly connected together to form a closed loop. When the temperatures of the two joints are not equal (T > T0), an electromotive force will be generated in the loop, thus forming a thermal current. When the temperature of the cold end is fixed, the thermoelectric potential is a single - valued function of the hot - end temperature T. According to the magnitude of the generated thermoelectric potential, the specific value of the hot - end temperature T can be known. The sensor uses a K - type thermocouple and selects a K - type thermocouple alloy as the metal sensing layer. Arrange multiple groups of sensors on the substrate according to requirements, and multiple pairs of thermoelectric couple loops can be arranged in each group. The circuit routing design should be as symmetrical and beautiful as possible and convenient for cutting and processing. At the same time, when considering the planar size of the sensor, the success rate of sensor production should also be taken into account, that is, the line - width size of a single electrode and the distance between each pair of electrodes should not be too small. In addition, to reduce the difficulty of wire connection and ensure insulation between each pair of pads, the side - length size of a single square pad and the distance between each pair of pads should not be too small either.

[0182] 2) A metal copper sheet with a diameter of 4 inches and a thickness of 800 μm is used as the substrate for sensor deposition. The melting point of copper is about 1083 °C, the boiling point is about 2567 °C, and the Vickers hardness is about 350 MPa. It has good ductility and thermal and electrical conductivity, and is a relatively inactive heavy metal. Considering both thermal conductivity and material strength, it is more suitable to choose it as the protective layer. After the copper sheet is polished, it should be ensured that the surface roughness is low, the surface is flat and smooth, and there are no obvious scratches, pits and other defects. Pretreatments such as substrate cleaning and deposition of a metal transition layer are carried out.

[0183] 3) To enhance the bonding between the metal substrate and the subsequent insulating layer, a metal titanium layer with a thickness of 10 - 100 nm needs to be deposited on the surface of the metal transition layer through a magnetron sputtering process as shown in Figure 3 . If the surface of the substrate is relatively rough, the deposition thickness can be appropriately increased. Sputtering means using a plasma with kinetic energy above dozens of electron volts to bombard the surface of a solid target. Atoms near the surface obtain part of the energy carried by the incident particles. When the energy is sufficient to overcome the binding energy, these atoms will break away from the solid and enter the vacuum chamber, and then deposit on the substrate. The specific sputtering process parameters are: sputtering power 200 - 600 W, sputtering rate 10 - 20 nm / min, sputtering time 2 - 6 min. Of course, for different equipment platforms, the parameters may be adjusted.

[0184] 4) Next, an insulating layer needs to be made, that is, a layer of polyimide is coated on the surface of the titanium layer through a spin coating process. It has good comprehensive thermal and mechanical properties. The thermal decomposition temperature is as high as 500 - 600 °C, the long-term use temperature range is -200 - 300 °C, and there is no obvious melting point. It is one of the polymers with the best thermal stability. At the same time, it has excellent mechanical properties and heat aging resistance. Its tensile strength is about 170 - 400 MPa, and the elastic modulus is about 3 - 4 GPa. After aging treatment at 200 °C for 1500 hours, the tensile strength decreases very little. It has high insulation performance, the dielectric constant is usually about 3.4, and the dielectric loss is only 0.004 - 0.007, belonging to F to H grade insulating materials. First, use a spin coater to spin coat on the substrate. Then, soft bake on a hot plate. Next, bake and cure in an oven. Considering both good thermal conductivity and insulation protection, it is more appropriate to control the thickness of this insulating layer to be 0.5 - 5 μm after baking and curing.

[0185] 5) To fabricate the designed sensor plate for the next step of sputter deposition of the metal sensing layer, a layer of photoresist with a thickness of 1 - 5 μm needs to be coated on the surface of the insulating layer through the spin coating process. Then, pre-baking is carried out on a hot plate to remove the solvent in the photoresist and enhance the adhesion. Next, the pre-baked substrate wafer is placed on a lithography machine for exposure. After exposure, the substrate wafer is placed on a hot plate for post-baking to stimulate the acid generated by the PAG photosensitive acid generator in the chemically amplified photoresist to react with the protecting groups on the photoresist and remove the groups so that it can be dissolved in the developer, while reducing the standing wave effect. Subsequently, the post-baked substrate wafer is placed in the developer for development. After development is completed, it is washed with deionized water and dried with nitrogen, finally forming a plate with the shape and size of the sensor, as Figure 5 shown.

[0186] 6) Next, start fabricating the most core metal sensing layer. First, sputter a layer of titanium metal with a thickness of 10 - 100 nm according to the process method described in step 3). Then, magnetron sputter deposit a layer of nickel-based alloy with a thickness of 300 - 900 nm. The specific sputtering process parameters are: sputtering power 200 - 600 W, sputtering rate 10 - 20 nm / min, sputtering time 30 - 80 min. Of course, for different equipment platforms, the parameters may be adjusted. Then, sputter a layer of titanium metal with a thickness of 10 - 100 nm according to the process method described in step 3). After deposition is completed, take out the substrate wafer and soak it in acetone for the stripping process to remove the remaining photoresist on the substrate wafer, wash it with deionized water and dry it with nitrogen, and complete the deposition of the first-pole sensing circuit on the substrate wafer, as Figure 6 shown.

[0187] 7) Repeat the above two process steps. First, coat a layer of photoresist with a thickness of 1 - 5 μm. Then, sputter deposit a layer of titanium metal with a thickness of 10 - 100 nm. Next, sputter deposit a layer of nickel-based alloy with a thickness of 300 - 900 nm for the other pole. The specific sputtering process parameters are: sputtering power 200 - 600 W, sputtering rate 10 - 20 nm / min, sputtering time 30 - 80 min. Of course, for different equipment platforms, the parameters may be adjusted. Then, sputter deposit a layer of titanium metal with a thickness of 10 - 100 nm. After deposition is completed, through soaking, stripping, washing and drying, complete the deposition of the second-pole sensing circuit on the substrate wafer, as Figure 7 shown. Thus, the fabrication of the most core metal sensing layer is completed.

[0188] 8) To prevent the thin-film sensor from being worn and eroded in harsh environments and enhance its durability, it needs to be encapsulated and protected. First, cut a copper sheet in a crown shape according to the size characteristics of the sensor. Then, using the electroplating process and the magnetron sputtering process, deposit a metal transition layer with a thickness of 5 - 30 μm and a metal bonding layer of titanium with a thickness of 10 - 100 nm on the surface of the copper sheet in sequence to prepare for the next encapsulation step, as Figure 10 shown.

[0189] 9) Next, first coat a layer of polyimide with a thickness of 1 - 5 μm on the already fabricated metal sensing layer through the spin coating process. Use its adhesiveness to attach the copper sheet prepared in the previous step to the substrate, exactly exposing the pad part. Then bake and cure it in an oven to form a sandwich-layered encapsulation structure. Finally, remove the insulating layer on the surface of the pad through the plasma etching process to expose the pad for the wire, as shown in Figure 8 shown.

[0190] 10) The next step is to perform the final wiring step. First, use conductive silver glue to connect all the pads on the metal sensing layer to compensation wires with a diameter of 0.2 - 0.5 mm. Then, after baking on a hot plate, apply a layer of epoxy resin for covering to reduce the influence of external forces on the connection part between the wire and the pad and prevent the wire from breaking. After aging and curing for 10 - 36 hours, the production of the entire sensor is completed. It detects temperature by collecting potential signals, and the metal sensing layer is its core working layer, as shown in Figure 9 shown.

[0191] In all the above solutions, polyimide can be replaced by an oxide. Correspondingly, it needs to be realized through processes such as electron beam evaporation and atomic layer deposition.

[0192] The micro-nano thin-film sensor based on a metal substrate proposed by the present invention is small in size, fast in response, has less interference with the original temperature field, can capture the instantaneous dynamic changes of the temperature field in a timely and accurate manner, can be flexibly and conveniently installed in a narrow space and closer to the measurement point for detection, and can arrange multiple groups of thermocouple circuits at one detection point according to requirements to achieve local multi-point detection; the sandwich-layered encapsulation structure based on a metal copper substrate with relatively high melting point, hardness, and good thermal and electrical conductivity makes the sensor have good high-temperature and high-pressure resistance and anti-interference performance, can effectively avoid wear and erosion, can effectively ensure the use effect of the thin-film sensor in harsh industrial environments, and helps to greatly improve its durability and service life. The present invention can significantly improve the technical limitations and drawbacks of traditional temperature detection elements in terms of spatial size, dynamic response, and encapsulation protection, provides an important hardware basis and technical means for the optimization and innovation of traditional temperature measurement methods, and is worthy of popularization and application in various temperature detection fields.

[0193] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the present technical solution, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A manufacturing method of a micro-nano thin film temperature sensor, characterized in that: The manufacturing method includes the following steps: S11: Based on the temperature detection range, design the shape, size and quantity of the sensor, and manufacture a mask plate for the micro-nano thin film temperature sensor; S12: Select a metal substrate for the micro-nano thin film temperature sensor; S13: Deposit a metal transition layer on the metal substrate; S14: Use the magnetron sputtering process to deposit a metal bonding layer on the surface of the metal transition layer; S15: Use the spin coating process to coat an insulating layer on the surface of the metal bonding layer; S16: Soft bake the metal substrate deposited with the metal transition layer, metal bonding layer and insulating layer on a hot plate; after soft baking, cure the metal substrate in an oven; S17: Use the spin coating process to coat a photoresist with a thickness range of [1 μm, 5 μm] on the surface of the insulating layer, and perform pre-baking on a hot plate; use the mask plate to expose the pre-baked metal substrate on a lithography machine; after exposure, place the metal substrate on a hot plate for post-baking, and then place it in a developer for development; S18: Use the magnetron sputtering process to sequentially deposit a metal bonding layer, a first-pole metal sensing layer, a second-pole metal sensing layer and a metal bonding layer on the surface of the photoresist layer; S19: Immerse and strip the metal substrate in acetone; after stripping, clean and dry the metal substrate to form a first-pole metal sensing layer; the first-pole metal sensing layer has a sensor pad for connecting a wire; S110: Coat a photoresist with a thickness range of [1 μm, 5 μm] on the surface of the first-pole metal sensing layer, and perform pre-baking on a hot plate; use the mask plate to expose the pre-baked metal substrate on a lithography machine; after exposure, place the metal substrate on a hot plate for post-baking, and then place it in a developer for development; S111: Repeat steps S18 and S19 to fabricate a second-pole metal sensing layer; the second-pole metal sensing layer has a sensor pad for connecting a wire; S112: Cut the protective layer based on the sensor size, and sequentially deposit a metal transition layer and a metal bonding layer on the bottom surface of the protective layer; S113: Deposit an insulating layer on the second-pole metal sensing layer, and bond the protective layer to the insulating layer to form a micro-nano thin film temperature sensor to be encapsulated; the sensor pads of the first-pole metal sensing layer and the second-pole metal sensing layer are not covered by the protective layer; S114: Bake and cure the micro-nano thin film temperature sensor to be encapsulated to form a sandwich-layered encapsulation structure; S115: Use the plasma etching process to remove the insulating layer on the surface of the sensor pad; S116: Connect wires to the sensor pads, and use a hot plate for baking and curing; after baking and curing, apply a layer of epoxy resin on the sensor pads and cure for a time t to form a micro-nano thin film temperature sensor; t > 0.

2. The manufacturing method of the micro-nano thin film temperature sensor according to claim 1, characterized in that: The time t = [10 h, 36 h].

3. A manufacturing method of a micro-nano thin film temperature sensor, characterized in that: The manufacturing method includes the following steps: S31: According to the requirements of temperature detection, design and manufacture a mask plate for the micro-nano thin film temperature sensor, including the shape, size and quantity of the sensor; S32: Use a metal substrate with a diameter of 4 inches and a thickness of 800 μm for sensor deposition. After polishing the copper sheet, deposit a metal transition layer with a thickness of 5 - 30 μm on its surface. S33: Deposit a layer of titanium metal with a thickness of 10 - 100 nm on the surface of the metal transition layer through magnetron sputtering. S34: Coat a layer of polyimide, an organic polymer material with a thickness of 1 - 5 μm, on the surface of the titanium layer through spin coating, and perform soft baking and curing in a hot plate and an oven respectively. S35: Coat a layer of photoresist with a thickness of 1 - 5 μm on the surface of the insulating layer through spin coating, perform pre-baking on a hot plate, then use a mask plate for exposure on a lithography machine. After completion, place it on the hot plate for post-baking, and then place it in a developer for development. After cleaning and drying, form a plate with the shape and size of the sensor. S36: Deposit three layers of metal on the surface of the photoresist layer in sequence through magnetron sputtering, namely titanium metal with a thickness of 10 - 100 nm, nickel-based alloy with a thickness of 300 - 900 nm, and titanium metal with a thickness of 10 - 100 nm. Then soak it in acetone for soaking and stripping, and after cleaning and drying, form the first pole sensing circuit. S37: Repeat the two process steps of S35 and S36. After coating a new layer of photoresist with a thickness of 1 - 5 μm and performing exposure and development, deposit titanium metal, the other pole nickel-based alloy, and titanium metal in sequence, and form the second pole sensing circuit. S38: Cut the protective layer metal sheet in a crown shape according to the size characteristics of the sensor, and deposit a metal transition layer and a metal bonding layer in sequence using electroplating and magnetron sputtering processes. S39: Coat another layer of polyimide with a thickness of 1 - 5 μm on the completed metal sensing layer through spin coating. Use its adhesiveness to bond the copper sheet processed in the previous step to the substrate, just exposing the pad part. Then perform baking and curing to form a sandwich-layered packaging structure. Finally, remove the insulating layer on the surface of the pad through plasma etching to expose the pad for the wire. S310: Connect the compensation wires to all the pads on the metal sensing layer with conductive silver glue. After baking and curing on a hot plate, apply a layer of epoxy resin, and then complete the production of the sensor after 10 - 36 hours of aging and curing. It detects temperature by collecting potential signals, and the metal sensing layer is its core working layer.

4. A manufacturing method of a micro-nano thin film temperature sensor, characterized in that: The manufacturing method includes the following steps: S41: First, according to the requirements of temperature detection, design a micro-nano thin film temperature sensor, including the shape, size, and quantity of the sensor; the sensor uses a K-type thermocouple, and selects a K-type thermocouple alloy as the metal sensing layer; arrange multiple groups of sensors on the substrate according to requirements, and arrange multiple pairs of thermoelectric couple circuits in each group of sensors; the line width dimension of a single electrode and the distance between each pair of electrodes are ≥ 5 μm, and the side length dimension of a single square pad and the distance between each pair of pads are ≥ 3 mm. S42: Use a 4-inch-diameter, 800-μm-thick copper metal sheet as the substrate for sensor deposition and select it as the protective layer; after the copper sheet is polished, perform pre-treatment of substrate cleaning and deposition of the metal transition layer. S43: Deposit a 10-100 nm-thick metal titanium layer as the metal bonding layer on the surface of the metal transition layer by magnetron sputtering; if the surface of the substrate is rough, increase the deposition thickness. S44: Fabricate the insulating layer. Spin-coat a layer of polyimide on the surface of the titanium layer by spin-coating process, and perform spin-coating on the substrate using a spin coater; then, perform soft baking on a hot plate; next, perform baking and curing in an oven; considering both good heat conduction and insulation protection, the thickness of this insulating layer is controlled to be 0.5-5 μm after baking and curing. S45: Spin-coat a 1-5 μm-thick photoresist on the surface of the insulating layer by spin-coating process; perform pre-baking on a hot plate to remove the solvent in the photoresist and enhance adhesion; place the pre-baked substrate on a lithography machine for exposure; after exposure, place the substrate on a hot plate for post-baking to stimulate the acid generated by the PAG photosensitive acid generator in the chemically amplified photoresist to react with the protecting group on the photoresist and remove the group so that it can be dissolved in the developer, and at the same time reduce the standing wave effect; place the post-baked substrate in the developer for development, after development is completed, wash it with deionized water and dry it with nitrogen, and finally form a plate with the shape and size of the sensor. S46: Fabricate the metal sensing layer; sputter a 10-100 nm-thick metal titanium layer according to the process method in S43; then deposit a 300-900 nm-thick nickel-based alloy by magnetron sputtering, and then sputter a 10-100 nm-thick metal titanium layer according to the process method in S43; after deposition is completed, take out the substrate and soak it in acetone for the soaking and stripping process to remove the remaining photoresist on the substrate, wash it with deionized water and dry it with nitrogen, and complete the deposition of the first-pole sensing circuit on the substrate. S47: Repeat the two process steps of S45 and S46. First, spin-coat a 1-5 μm-thick photoresist; then sputter and deposit a 10-100 nm-thick metal titanium layer; then sputter and deposit a 300-900 nm-thick nickel-based alloy for the other pole, and then sputter and deposit a 10-100 nm-thick metal titanium layer; after deposition is completed, perform soaking and stripping, washing and drying, and complete the deposition of the second-pole sensing circuit on the substrate to complete the fabrication of the metal sensing layer. S48: To prevent the thin-film sensor from being worn and eroded in a harsh environment, perform encapsulation protection; first cut a copper sheet in a crown shape according to the size characteristics of the sensor, and then also use electroplating process and magnetron sputtering process to sequentially deposit a 5-30 μm-thick metal transition layer metal and a 10-100 nm-thick metal bonding layer metal titanium on the surface of the copper sheet. S49: Apply a layer of polyimide with a thickness of 1 - 5 μm on the already fabricated metal sensing layer through a spin coating process. Use its adhesiveness to bond the copper sheet prepared in the previous step to the substrate, exposing the pad area. Then bake and cure it in an oven to form a sandwich - layer packaging structure. Finally, remove the insulating layer on the pad surface through a plasma etching process to expose the pads for wiring. S410: Use conductive silver paste to connect all the pads on the metal sensing layer to compensation wires with a diameter of 0.2 - 0.5 mm. Then, after baking on a hot plate, apply a layer of epoxy resin for covering to reduce the influence of external force on the connection part between the wire and the pad and prevent the wire from breaking. After aging and curing for 10 - 36 hours, complete the fabrication of the entire sensor and detect the temperature by collecting the potential signal.

5. The manufacturing method of the micro-nano thin film temperature sensor according to claim 4, characterized in that: The sputtering is to bombard the surface of a solid target with plasma having kinetic energy above dozens of electron volts. Atoms near the surface obtain part of the energy carried by the incident particles. When the energy is sufficient to overcome the binding energy, these atoms will break away from the solid and enter the vacuum chamber, and then deposit on the substrate.

6. The manufacturing method of the micro-nano thin film temperature sensor according to claim 4, characterized in that: In S43, the process parameters of sputtering are: sputtering power 200 - 600 W, sputtering rate 10 - 20 nm / min, and sputtering time 2 - 6 min.

7. The manufacturing method of the micro-nano thin film temperature sensor according to claim 4, characterized in that: In S46, the process parameters of sputtering are: sputtering power 200 - 600 W, sputtering rate 10 - 20 nm / min, and sputtering time 30 - 80 min.

8. The manufacturing method of the micro-nano thin film temperature sensor according to claim 4, characterized in that: In S47, the process parameters of sputtering are: sputtering power 200 - 600 W, sputtering rate 10 - 20 nm / min, and sputtering time 30 - 80 min.

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