Flexible thermosensitive buried resistance thin film material, preparation method thereof and electronic equipment

Abstract

The invention relates to a flexible thermosensitive buried resistance film material, a preparation method thereof and electronic equipment, the flexible thermosensitive buried resistance film material comprises an electrode layer (1), a thermosensitive layer (3) and a flexible substrate (2) which are sequentially stacked, the thermosensitive layer (3) is formed by compounding a thermosensitive material and a conductive filler, and the conductive filler is introduced into the thermosensitive layer; and by combining the design of the flexible substrate, the material is endowed with excellent flexibility, bendability and high sensitivity. The flexible thermosensitive embedded resistance thin film material can be directly embedded in a circuit, the integration level of a device is remarkably improved, the flexible thermosensitive embedded resistance thin film material has good stability, meanwhile, the flexible thermosensitive embedded resistance thin film material is closer to a heat source, accurate temperature monitoring is achieved, and the flexible thermosensitive embedded resistance thin film material is suitable for temperature monitoring in the fields of flexible electronic devices, wearable equipment, electronic packaging and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat-sensitive buried resistance materials and preparation methods thereof, in particular to a flexible heat-sensitive buried resistance film material, a preparation method thereof and an electronic device. BACKGROUND

[0002] With the rapid rise of smart wearable electronic devices, flexible wearable devices have the advantages of softness, flexibility, lightness, portability, sensitivity, etc., and show broad application prospects in the fields of health monitoring, intelligent medical treatment, intelligent textiles, flexible electronic products, etc. In these application scenarios, accurate and real-time monitoring of temperature is crucial. As one of the core components, flexible temperature sensors need to meet the performance requirements in complex application scenarios, and the development of high-performance temperature sensors suitable for flexible electronic devices is one of the current research hotspots.

[0003] Thermosensitive materials have the characteristic that the resistance value changes with the increase of temperature, and are widely used in the fields of temperature measurement, control and compensation. Traditional thermistors mostly use thick film or bulk resistance, which are usually sintered or annealed. Although they have high temperature sensitivity and long-term stability, they still have the following problems: 1. insufficient flexibility: rigid structure, difficult to adapt to the deformation requirement of flexible electronic devices; 2. high brittleness: easy to break under bending or stretching conditions; 3. complex process: high-temperature sintering or annealing process not only increases the manufacturing cost, but also limits its application on flexible substrates; 4. large volume: difficult to be directly buried in the circuit, limiting its application in miniaturized and integrated devices; 5. far from heat source: due to the limitations of volume and structure, it is difficult to closely adhere to the heat source, resulting in slow temperature response speed, making it difficult to achieve real-time, efficient and accurate temperature monitoring.

[0004] The above limitations make it difficult for traditional thermosensitive materials to meet the high-performance requirements of flexible electronic devices for temperature monitoring. Therefore, it is urgent to develop a flexible heat-sensitive buried resistance film material with high flexibility, high sensitivity, low temperature preparation process and high integration, to meet the high-performance requirements of flexible electronic devices for temperature sensing elements, and promote its application and development in the fields of smart wearable devices, flexible electronic circuits, 3D packaging, etc. SUMMARY

[0005] In view of the challenges of the prior art, the embodiments of the present application provide a flexible heat-sensitive buried resistance film material, a preparation method thereof and an electronic device, which solve the problems of traditional thermistors and have the advantages of excellent flexibility, high sensitivity and high integration.

[0006] In order to achieve the above-mentioned purpose, the embodiments of the present application provide the following technical solutions:

[0007] A flexible heat-sensitive buried resistance film material, comprising an electrode layer 1, a heat-sensitive layer 3 and a flexible substrate 2 which are sequentially stacked, wherein the heat-sensitive layer 3 is formed by a composite structure of a heat-sensitive material and a conductive filler.

[0008] Preferably, the electrode layer 1 is selected from at least one of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold.

[0009] Preferably, the electrode layer 1 is selected from copper.

[0010] Preferably, the electrode layer 1 has a thickness of 10-25 μm and a surface roughness Rz of 1-3 μm.

[0011] Preferably, the heat-sensitive layer 3 is formed by a composite structure of a heat-sensitive material and a conductive filler.

[0012] Preferably, the heat-sensitive material is a transition metal oxide and the conductive filler is a carbon nanomaterial in the form of a sheet or a wire.

[0013] Preferably, the transition metal oxide contains Mn, Co, Ni, O and the like or the transition metal oxide contains Co, Ni, Fe, O and the like, and the conductive filler is at least one of graphite, carbon nanotubes and graphene.

[0014] Preferably, the flexible substrate is selected from at least one of epoxy resin, polyester resin, polyurethane resin, acrylic resin, alkyd resin, polyamide resin, polyimide resin and polyether ether ketone resin.

[0015] Preferably, the electrode layer 1 has a thickness of 10-25 μm, the heat-sensitive layer 3 has a thickness of 100-300 nm and the flexible substrate 2 has a thickness of 20-30 μm. The thickness of the electrode layer 1 can be 10 μm, 15 μm, 20 μm, 25 μm or any interval formed by two values less than 25 μm; the thickness of the heat-sensitive layer 3 can be 100 nm, 150 nm, 180 nm, 200 nm, 220 nm, 250 nm, 280 nm or any interval formed by two values less than 300 nm; and the thickness of the flexible substrate 2 can be 20 μm, 22 μm, 25 μm, 28 μm or any interval formed by two values less than 30 μm.

[0016] The embodiment of the present application also provides a preparation method of the flexible heat-sensitive buried resistance film material, comprising the following steps:

[0017] Step 1: performing ion source treatment on the surface of the electrode layer 1 to remove surface contaminants and improve adhesion;

[0018] Step 2: uniformly depositing heat-sensitive material on the surface of the electrode layer 1;

[0019] Step 3: uniformly depositing conductive filler on the surface of the heat-sensitive material;

[0020] Step 4: repeating the process of Step 2 and Step 3 for 5-10 times to form a heat-sensitive layer 3 with a total thickness of 100-300 nm;

[0021] Step 5: preparing a flexible substrate 2 on the heat-sensitive layer 3 by a coating process;

[0022] Step 6: performing high-temperature treatment on the composite material composed of the electrode layer 1, the heat-sensitive layer 3, and the flexible substrate 2, wherein the high-temperature curing process is performed under the protection of inert gas (nitrogen or argon) at a temperature of 100-300°C for 2-3 hours.

[0023] Preferably, the deposition method in Step 2 is magnetron sputtering, and the magnetron sputtering process is performed in a mixed atmosphere of argon and oxygen at a sputtering power of 2-8 kW, a sputtering time of 30-60 min, and a sputtering gas pressure of 0.2-0.5 Pa.

[0024] The embodiment of the present application also provides an electronic device containing the flexible heat-sensitive buried resistor film material or prepared by the preparation method of the flexible heat-sensitive buried resistor film material.

[0025] For example, a specific preparation method of a flexible heat-sensitive buried resistor film material includes the following steps:

[0026] Step ①: preparing a copper foil as the electrode layer 1 by an electrolytic method, controlling the temperature to be 30-50°C, the copper liquid concentration to be 50-80 g / L, the current density to be 10-50 A / dm 2 and different types of additives, with a thickness of 10-25 μm and a surface roughness of 1-3 μm, and good electrical conductivity;

[0027] Step ②: checking the appearance of the copper foil and measuring the gram weight, whether there are pits, pinholes, or copper tumors, etc.

[0028] Step ③: placing the copper foil in a vacuum chamber, vacuumizing to 10 -4 Pa, and performing ion source treatment on the surface of the copper foil in an argon atmosphere to remove surface contaminants and improve adhesion;

[0029] Step ④: uniformly depositing a layer of transition metal oxide on the surface of the copper foil by a magnetron sputtering process in a mixed atmosphere of argon and oxygen at a sputtering gas pressure of 0.2-0.5 Pa and a sputtering power of 5-8 kW, wherein the transition metal oxide contains elements such as Mn, Co, Ni, O, or the transition metal oxide contains elements such as Co, Ni, Fe, O, and the transition metal oxide is in a spinel structure.

[0030] Step ⑤: continue to uniformly deposit a conductive filler layer of graphite, carbon nanotubes, or graphene, etc. on the surface of the thermosensitive material layer by a magnetron sputtering process, with a sputtering pressure of 0.2-0.5 Pa and a sputtering power of 2-5 kW;

[0031] Step ⑥: repeat the process of Step ④ and Step ⑤ for 5-10 times, with a sputtering time of 30-60 min, to form a thermosensitive layer 3 with a total thickness of 100-300 nm.

[0032] Step ⑦: load a polymer material such as polyurethane (TPU) on the surface of the thermosensitive layer by a coating method as a flexible substrate 2.

[0033] Step ⑧: subject the obtained electrode layer 1, thermosensitive layer 3, and flexible substrate 2 composite structure to high-temperature treatment under an inert atmosphere of nitrogen or argon, at a temperature of 100-300℃ for 2-3 hours. After cooling to room temperature, the flexible thermosensitive buried resistance thin film material is obtained.

[0034] It should be noted that the thermosensitive buried resistance thin film material in the present application can be NTC or PTC, i.e. negative temperature coefficient or positive temperature coefficient. In addition, the thermosensitive layer 3 can be a single-layer structure or a multi-layer structure, wherein a single layer of thermosensitive material and a single layer of conductive filler form a single-layer structure of the thermosensitive layer 3.

[0035] For example, the application of a flexible negative temperature coefficient (NTC) thermosensitive buried resistance thin film material in temperature monitoring in a flexible circuit is as follows:

[0036] Step 1: prepare a copper foil as the electrode layer 1 by electrolysis, with process parameters of the raw foil controlled at a temperature of 30-50℃, a copper liquid concentration of 50-80 g / L, and a current density of 10-50 A / dm 2 and different types of additives, with a thickness of 10-25 μm and a surface roughness of 1-3 μm, and good electrical conductivity;

[0037] Step 2: check the appearance of the copper foil and measure the gram weight, whether there are pits, pinholes, or copper tumors, etc.

[0038] Step 3: place the copper foil in a vacuum chamber, vacuumize to 10 -4 Pa, and perform ion source treatment on the surface of the copper foil under an argon atmosphere to remove surface contaminants and improve adhesion;

[0039] Step 4: uniformly deposit a layer of thermosensitive buried resistance thin film material on the surface of the copper foil by a magnetron sputtering process in a mixed atmosphere of argon and oxygen, with a sputtering pressure of 0.2-0.5 Pa and a sputtering power of 5-8 kW;

[0040] Step 5: continue to uniformly deposit a conductive filler layer of graphite, carbon nanotubes or graphene on the surface of the heat-sensitive material layer by a magnetron sputtering process, with a sputtering pressure of 0.2-0.5 Pa and a sputtering power of 2-5 kW;

[0041] Step 6: repeat the process of steps 4 and 5 for 5-10 times, with a sputtering time of 30-60 min, to form a heat-sensitive layer 3 with a total thickness of 100-300 nm.

[0042] Step 7: apply a polyurethane (TPU) polymer material on the surface of the heat-sensitive layer by a coating method, as a flexible substrate 2.

[0043] Step 8: subject the obtained composite structure of the electrode layer 1, the heat-sensitive layer 3 and the flexible substrate 2 to high-temperature treatment in an inert atmosphere of nitrogen or argon, with a flexible substrate thickness of 20-30 μm, a temperature of 100-300 °C and a time of 2-3 hours. After cooling to room temperature, the flexible negative temperature coefficient (NTC) heat-sensitive buried resistor thin film material is obtained.

[0044] Step 9: obtain a three-layer structure of the electrode layer 1, the heat-sensitive layer 3 and the flexible substrate 2, to ensure good bonding force between the layers.

[0045] Step 10: design a circuit pattern on the surface of the electrode layer by a photolithography and mask process, and etch away the unprotected copper by alkaline etching, to form a circuit structure.

[0046] Step 11: etch away the heat-sensitive layer outside the circuit by an acid etching process through a photolithography and mask process, to confirm that only the heat-sensitive layer in the circuit area is reserved.

[0047] Step 12: etch away the copper in the windowed area by alkaline etching on the circuit through a photolithography and mask process, to expose the underlying heat-sensitive layer, complete the windowed design and realize series connection in the circuit.

[0048] The embodiment of the present application provides a flexible heat-sensitive buried resistor thin film material, which has a multi-layer structure and can be directly buried in a circuit, meets the demand for miniaturization of units in a multi-functional integrated circuit manufacturing process and significantly improves the integration degree and stability of a device; meanwhile, due to the ultra-thin structure and flexible characteristics, the material can be closer to a heat source and realize accurate and rapid temperature monitoring. The present application not only has universality for development of a flexible buried resistor thin film material, but also provides a new solution and development direction for temperature monitoring of flexible electronic technology. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 FIG. 1 is a structural schematic diagram of a flexible heat-sensitive buried resistor thin film material in the embodiment of the present application;

[0050] Figure 2 FIG. 2 is a preparation process flow chart of the flexible heat-sensitive buried resistor thin film material in the embodiment of the present application;

[0051] Figure 3 The resistance-bending times curve of the flexible heat-sensitive buried resistance thin film material in the embodiment of the present application;

[0052] Figure 4 The resistance-temperature curve of the flexible heat-sensitive buried resistance thin film material before and after bending 10000 times in the embodiment of the present application;

[0053] Wherein, 1, electrode layer; 2, flexible substrate layer; 3, heat-sensitive layer. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical scheme and advantages of the present application more clear and explicit, the technical scheme in the present application is described clearly and completely in combination with the specific embodiments of the present application. It should be understood that the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the protection scope of the present application.

[0055] Embodiment 1:

[0056] A preparation method of a flexible negative temperature coefficient (NTC) heat-sensitive buried resistance thin film material applied to temperature monitoring in a flexible circuit, the specific operation steps are as follows, referring to Figure 2 :

[0057] Step 1: electrolytic method is used to prepare copper foil as electrode layer 1, the temperature is controlled to be 30-50℃, the copper liquid concentration is controlled to be 50-80g / L, the current density is controlled to be 10-50A / dm 2 and different types of additives, the thickness is 10-25μm, the surface roughness is 1-3μm, and it has good conductivity;

[0058] Step 2: check the appearance of the copper foil and measure the gram weight, whether there are pits, pinholes or copper tumors, etc.

[0059] Step 3: place the copper foil in a vacuum cavity, vacuumize to 10 -4 Pa, perform ion source treatment on the surface of the copper foil under argon atmosphere, remove surface contaminants and improve adhesion;

[0060] Step 4: use a magnetron sputtering process to uniformly deposit a layer of heat-sensitive material containing Co, Ni, Fe and O in spinel structure on the surface of the copper foil under the mixed atmosphere of argon and oxygen, the sputtering gas pressure is 0.2-0.5Pa, and the sputtering power is 5-8kW;

[0061] Step 5: uniformly deposit a graphite conductive filler layer on the surface of the heat-sensitive material layer by a magnetron sputtering process, the sputtering gas pressure is 0.2-0.5Pa, and the sputtering power is 2-5kW;

[0062] Step 6: Repeat the process of Step 4 and Step 5 for 5-10 times, with sputtering time of 30-60 min, to form a total thickness of 100-300 nm of the thermosensitive layer 3.

[0063] Step 7: Apply a polyimide (PI) polymer film material on the surface of the thermosensitive layer as the flexible substrate 2.

[0064] Step 8: High-temperature treatment of the obtained electrode layer 1, thermosensitive layer 3, and flexible substrate 2 composite structure under an inert atmosphere of nitrogen or argon, with a flexible substrate thickness of 20-30 μm, a temperature of 100-300 °C, and a time of 2-3 hours. Cool to room temperature and remove, to obtain a flexible negative temperature coefficient (NTC) thermosensitive buried resistance thin film material.

[0065] Preparation of a flexible circuit:

[0066] Step 9: Obtain a three-layer structure of the electrode layer 1, thermosensitive layer 3, and flexible substrate 2, as shown in Figure 1 , to ensure good bonding force between the layers.

[0067] Step 10: Design a circuit pattern on the surface of the electrode layer through a photoetching and mask process, and alkaline etch away the unprotected copper to form a circuit structure.

[0068] Step 11: Acidic etch away the thermosensitive layer 3 outside the circuit through a photoetching and mask process, to confirm that only the thermosensitive layer 3 in the circuit area is retained.

[0069] Step 12: Alkaline etch away the copper in the windowed area on the circuit through a photoetching and mask process, to expose the underlying thermosensitive layer, complete the windowed design, and can be connected in series in the circuit.

[0070] Example 2:

[0071] A preparation method of a flexible negative temperature coefficient (NTC) thermosensitive buried resistance thin film material applied to a flexible circuit, with specific operation steps as follows, as shown in Figure 2 :

[0072] Step 1: Prepare a copper foil as the electrode layer 1 by electrolysis, with a temperature of 30-50 °C, a copper liquid concentration of 50-80 g / L, a current density of 10-50 A / dm 2 , and different types of additives, a thickness of 10-25 μm, a surface roughness of 1-3 μm, and good electrical conductivity;

[0073] Step 2: Check the appearance of the copper foil and measure the gram weight, whether there are pits, pinholes, or copper tumors, etc.

[0074] Step 3: Place the copper foil in a vacuum chamber, and vacuumize to 10 -4Pa, the copper foil surface is treated by ion source under argon atmosphere to remove surface contaminants and improve adhesion;

[0075] Step 4: A layer of spinel-structured thermosensitive material containing Co, Ni, Fe, and O is uniformly deposited on the surface of the copper foil by magnetron sputtering process in a mixed atmosphere of argon and oxygen, with a sputtering pressure of 0.2-0.5 Pa and a sputtering power of 5-8 kW;

[0076] Step 5: Continue to uniformly deposit a layer of carbon nanotube conductive filler on the surface of the thermosensitive material layer by magnetron sputtering process, with a sputtering pressure of 0.2-0.5 Pa and a sputtering power of 2-5 kW;

[0077] Step 6: Repeat the process of Step 4 and Step 5 for 5-10 times, with a sputtering time of 30-60 min, to form a thermosensitive layer 3 with a total thickness of 100-300 nm.

[0078] Step 7: Apply a polyurethane (TPU) polymer film material on the surface of the thermosensitive layer as a flexible substrate 2.

[0079] Step 8: The obtained electrode layer, thermosensitive layer, and flexible substrate composite structure are treated at high temperature under inert atmosphere of nitrogen or argon, with a flexible substrate thickness of 20-30 μm, a temperature of 100-300 °C, and a time of 2-3 hours. Cool to room temperature and remove, to obtain a flexible negative temperature coefficient (NTC) thermosensitive buried resistance thin film material.

[0080] Step 9: Obtain a three-layer structure of electrode layer 1, thermosensitive layer 3, and flexible substrate 2, as shown in Figure 1 , to ensure good bonding force between the layers.

[0081] Step 10: Design a circuit pattern on the surface of the electrode layer by photolithography and mask process, and etch away the unprotected copper by alkaline etching to form a circuit structure.

[0082] Step 11: Etch away the thermosensitive layer outside the circuit by photolithography and mask process, to confirm that only the thermosensitive layer in the circuit area is retained.

[0083] Step 12: Alkaline etch the copper in the windowed area on the circuit by photolithography and mask process to expose the underlying thermosensitive layer, complete the windowed design, and can be connected in series in the circuit.

[0084] Example 3:

[0085] A preparation method of a flexible negative temperature coefficient (NTC) thermosensitive buried resistance thin film material applied to a flexible circuit, the specific operation steps are as follows, as shown in Figure 2 :

[0086] Step 1: Electrolytic method is used to prepare copper foil as electrode layer 1, with temperature control at 30-50℃, copper liquid concentration at 50-80g / L, and current density at 10-50A / dm 2 and different types of additives, with thickness of 10-25μm, surface roughness of 1-3μm, and good electrical conductivity;

[0087] Step 2: Check the appearance of copper foil and measure the weight, whether there are pits, pinholes or copper tumor, etc.

[0088] Step 3: Place the copper foil in a vacuum chamber, vacuum to 10 -4 Pa, and perform ion source treatment on the surface of the copper foil under argon atmosphere to remove surface contaminants and improve adhesion;

[0089] Step 4: Use magnetron sputtering process to uniformly deposit a layer of spinel structure thermal sensitive material containing Co, Ni, Fe, O on the surface of the copper foil under the mixed atmosphere of argon and oxygen, with sputtering pressure at 0.2-0.5Pa and sputtering power at 5-8kW;

[0090] Step 5: Continue to uniformly deposit a layer of graphene conductive filler on the surface of the thermal sensitive material layer by magnetron sputtering process, with sputtering pressure at 0.2-0.5Pa and sputtering power at 2-5kW;

[0091] Step 6: Repeat the process of Step 4 and Step 5 for 5-10 times, with sputtering time at 30-60min, to form a thermal sensitive layer 3 with total thickness of 100-300nm.

[0092] Step 7: Apply polytetrafluoroethylene (PTFE) polymer film material on the surface of the thermal sensitive layer as a flexible substrate 2.

[0093] Step 8: Composite the obtained electrode layer 1, thermal sensitive layer 3 and flexible substrate 2 structure under inert atmosphere of nitrogen or argon for high temperature treatment, with flexible substrate thickness at 20-30μm, temperature at 100-300℃, and time at 2-3 hours. Cool to room temperature and take out, to obtain a flexible negative temperature coefficient (NTC) thermal sensitive buried resistance film material.

[0094] Step 9: Obtain a three-layer structure of electrode layer 1, thermal sensitive layer 3 and flexible substrate 2, refer to Figure 1 to ensure good bonding force between layers.

[0095] Step 10: Design a circuit pattern on the surface of the electrode layer through photolithography and mask process, and etch away the unprotected copper by alkaline etching to form a circuit structure.

[0096] Step 11: Etch away the thermal sensitive layer outside the circuit by acid etching through photolithography and mask process, to confirm that only the thermal sensitive layer in the circuit area is reserved.

[0097] Step 12: The copper in the windowed area on the line is etched alkaline using photolithography and masking processes to expose the underlying thermal layer, thus completing the windowed design, which can be connected in series in the circuit.

[0098] according to Figures 3-4 Based on the test results, flexible thermistor buried resistive film material, and preparation method, the embodiments of the present invention have the following beneficial effects: 1. High flexibility, capable of stable operation under bending and stretching conditions, suitable for flexible wearable devices; 2. High sensitivity, the composite structure and multilayer structure design of the thermistor material and conductive filler improve the temperature response speed; 3. Simple process, the low-temperature preparation process is compatible with flexible substrates, suitable for large-scale production; 4. High integration, can be directly embedded in flexible circuit boards or 3D packaged circuits, improving the level of miniaturization and integration; 5. Fast thermal response, closer to the heat source, achieving accurate and rapid temperature monitoring.

[0099] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions all fall within the protection scope of the present invention, and should be covered within the scope of the claims of the present invention as long as they do not depart from the spirit and substance of the technical solutions of the present invention.

Claims

1. A flexible heat-sensitive buried resist film material, characterized by, The flexible heat-sensitive buried resistance film material comprises an electrode layer (1), a heat-sensitive layer (3) and a flexible substrate (2) which are sequentially stacked, and the heat-sensitive layer (3) is formed by compounding a heat-sensitive material and a conductive filler.

2. The flexible heat sensitive buried resist film material of claim 1, wherein, The electrode layer (1) is at least one selected from aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold.

3. The flexible heat sensitive buried resist film material of claim 1, wherein, The thickness of the electrode layer (1) is 10-25 μm, and the surface roughness Rz thereof is 1-3 μm.

4. The flexible, heat-sensitive buried resist film material of claim 1, wherein, The heat-sensitive layer (3) is formed by a composite structure of a heat-sensitive material and a conductive filler.

5. The flexible heat sensitive buried resist film material of claim 4, wherein, The heat-sensitive material is a transition metal oxide, and the conductive filler is a carbon nano material.

6. The flexible heat sensitive buried resist film material of claim 5, wherein, The transition metal oxide contains Mn, Co, Ni and O elements, or the transition metal oxide contains Co, Ni, Fe and O elements, and the conductive filler is at least one of graphite, carbon nanotube and graphene.

7. The flexible, heat-sensitive buried resist film material of claim 1, wherein, The flexible substrate (2) is at least one selected from epoxy resin, polyester resin, polyurethane resin, acrylic resin, alkyd resin, polyamide resin, polyimide resin and polyether ether ketone resin.

8. A method of making a flexible heat-sensitive buried resist film material, characterized by, The preparation method comprises the following steps: Step 1: ion source treatment is performed on the surface of the electrode layer (1) to remove surface contaminants and improve adhesion; Step 2: the heat-sensitive material is uniformly deposited on the surface of the electrode layer (1); Step 3: the conductive filler is uniformly deposited on the surface of the heat-sensitive material; Step 4: steps 2 and 3 are repeated for 5-10 times to form the heat-sensitive layer (3) with a total thickness of 100-300 nm; Step 5: the flexible substrate (2) is prepared on the heat-sensitive layer (3) by a coating process; Step 6: high-temperature treatment is performed on the composite material composed of the electrode layer (1), the heat-sensitive layer (3) and the flexible substrate (2), and the high-temperature curing process is performed under the protection of inert gas nitrogen or argon, the temperature is 100-300 ℃, and the time is 2-3 hours.

9. The method for preparing the flexible thermistor buried resistive thin film material according to claim 8, characterized in that, The deposition mode in step 2 is magnetron sputtering, and the magnetron sputtering process is performed in a mixed atmosphere of argon and oxygen, the sputtering power is 2-8 kW, the sputtering time is 30-60 min, and the sputtering gas pressure is 0.2-0.5 Pa.

10. An electronic device, comprising: The electronic device contains the flexible heat-sensitive buried resistance film material according to any one of claims 1-7 or the flexible heat-sensitive buried resistance film material prepared by the preparation method according to any one of claims 8-9.

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