Method for forming gas-sensitive film, method for manufacturing gas sensor, and gas sensor

Abstract

The invention relates to the technical field of semiconductor processing, in particular to a forming method of a gas-sensitive film, a manufacturing method of a gas sensor and the gas sensor. The formation method of the gas-sensitive film specifically comprises the following steps: providing a photosensitive solution and a gas-sensitive solution combination; the photosensitive solution comprises a photoacid generator or a photosensitive cross-linking agent; the gas-sensitive solution comprises a nano material coated with a ligand; mixing the photosensitive solution and the gas-sensitive solution according to a preset proportion to obtain a mixed solution; and coating the surface of a target substrate with the mixed solution, and performing pattern curing treatment on the mixed solution under an ultraviolet light condition to obtain the gas-sensitive film on the target substrate. The formed gas-sensitive film has the characteristics of good consistency, good gas-sensitive effect and high preparation efficiency.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor processing technology, and in particular to a method for forming a gas sensitive film, a method for manufacturing a gas sensor, and a gas sensor. Background Art

[0002] Gas sensors with high integration are usually composed of a substrate and a gas-sensitive material thereon. According to the type of gas to be detected, a suitable gas-sensitive material can be selected. At present, most gas-sensitive materials are directly formed into a patterned film on the substrate by drop coating, but this method has disadvantages such as poor molding consistency and low preparation efficiency.

[0003] In the field of micro-nano processing, patterning is generally achieved with the help of a photoresist mask, depositing materials on the patterned photoresist mask, or etching materials on the substrate in areas not covered by the photoresist, and finally removing the photoresist on the substrate with a degumming solution, indirectly achieving the selective deposition of functional materials. However, for most gas-sensitive materials with excellent sensing performance, such as nano-metal oxides, they will be contaminated by the photoresist and solvents such as the developer or degumming solution used in the photolithography process, causing performance degradation. Therefore, how to provide a gas-sensitive material molding method that can improve the preparation efficiency while ensuring the performance of the gas sensor has become a technical problem that needs to be solved urgently. Summary of the invention

[0004] In order to solve the above technical problems, the present application discloses, on one hand, a method for forming a gas-sensitive film, which comprises the following steps:

[0005] A photosensitive solution and a gas-sensitive solution are provided; the photosensitive solution comprises a photoacid generator or a photosensitive crosslinker; the gas-sensitive solution comprises a nanomaterial encapsulated with a ligand;

[0006] Mixing the photosensitive solution and the gas-sensitive solution in a preset ratio to obtain a mixed solution;

[0007] After the mixed solution is coated on the surface of the target substrate, the mixed solution is subjected to pattern curing treatment under ultraviolet light conditions to obtain a gas-sensitive film on the target substrate.

[0008] Optionally, under the ultraviolet light condition, the photoacid generator or the photosensitive crosslinker can react with the nanomaterial to strip or crosslink some ligands on the surface of the nanomaterial;

[0009] The nanomaterials are dissolved in the developer by means of ligands.

[0010] Optionally, after coating the mixed solution on the surface of the target substrate, pattern curing the mixed solution under ultraviolet light to obtain a gas-sensitive film on the target substrate comprises:

[0011] The mixed solution is coated on the surface of the target substrate by a film-forming method such as spin coating, spray coating, blade coating or dip-pull coating;

[0012] Based on a preset mask, the mixed solution on the surface of the target substrate is subjected to ultraviolet curing treatment to obtain an initial gas-sensitive film;

[0013] The developer is used to remove the uncured area in the initial gas-sensitive film to obtain a gas-sensitive film on the target substrate.

[0014] Optionally, the photosensitive solution further comprises a target solvent;

[0015] The gas-sensitive solution also includes the target solvent;

[0016] The target solvent is a solvent that can dissolve the ligand.

[0017] Optionally, the nanomaterial includes any one of metals and their oxides, II-VI group nanocrystals and III-V group nanocrystals;

[0018] The nano metal and its oxide include one or a combination of two or more of gold, platinum, palladium, rhodium, zinc oxide, indium oxide, tungsten oxide, tin oxide, titanium oxide, copper oxide, nickel oxide or iron oxide;

[0019] The II-VI group nanocrystals include CdS, CdSe, CdTe, ZnS, ZnSe or ZnTe; the III-V group nanocrystals include InP, InAs, InN, GaAs, GaN, GaP, AlN, AlP or AlAs.

[0020] Optionally, the photoacid generator is capable of generating acidic protons under ultraviolet light irradiation;

[0021] The photosensitive crosslinking agent contains at least two photo-crosslinkable azide groups or carbene groups.

[0022] Optionally, the ligand includes a hydrocarbon organic ligand or an anionic ligand; the hydrocarbon organic ligand is an organic body containing at least 6 carbon atoms.

[0023] In another aspect, the present application also discloses a method for manufacturing a gas sensor, which comprises the following steps:

[0024] The gas sensitive film is formed on the sensitive material area of ​​the gas sensor according to the above-mentioned method for forming the gas sensitive film.

[0025] Optionally, the gas sensor includes a substrate and an IDT located on the substrate; the gas sensitive film is located on a surface of the IDT.

[0026] On the other hand, the present application also discloses a gas sensor, which is prepared by the above-mentioned manufacturing method.

[0027] By adopting the above technical solution, the method for forming the gas-sensitive film provided in the present application has the following beneficial effects:

[0028] By combining photosensitive materials (photosensitive molecules of the photoacid generator type or photosensitive cross-linking agent type) with nano gas-sensitive materials, a gas sensing material that can be directly photolithographically cured in a pattern can be obtained. By depositing the material on a target substrate, a gas-sensitive film is obtained, so that the formed gas-sensitive film has the characteristics of good consistency, good gas-sensing effect and high preparation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 A schematic diagram of a process for forming a gas-sensitive film according to an exemplary embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the reaction of a photoacid generator under ultraviolet light, which is an example of the present application;

[0032] Figure 3 The following is a schematic diagram of the reaction of a photosensitive crosslinker under ultraviolet light, which is an example of the present application;

[0033] Figure 4 A schematic diagram of the structure of an exemplary target substrate of the present application;

[0034] Figure 5 This is a schematic structural diagram of a target substrate having an initial gas-sensitive film formed thereon as an example of the present application;

[0035] Figure 6 This is a schematic structural diagram of a target substrate having a gas-sensitive film formed thereon as an example of the present application;

[0036] Figure 7 This is a SEM image of a gas-sensitive film after pattern curing exemplified in the present application;

[0037] Figure 8 This is a gas sensitivity test result diagram of an exemplary gas sensor of the present application.

[0038] The following is a supplementary description of the attached drawings:

[0039] 1-target substrate; 11-substrate; 12-interdigital transducer; 2-initial gas-sensitive film; 3-gas-sensitive film. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0041] The term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present application. In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "top", "bottom", etc. is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present application 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, and therefore cannot be understood as a limitation of the present application. In addition, the terms "first" and "second" are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may include one or more of the features explicitly or implicitly. Moreover, the terms "first", "second", etc. are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described here can be implemented in an order other than those illustrated or described here.

[0042] For the purpose of the following detailed description, it should be understood that the present invention may adopt various alternative changes and step sequences, unless expressly specified to the contrary. In addition, except in any operating examples, or otherwise indicated, all numbers representing the amount of ingredients used in the specification and claims should be understood to be modified by the term "about" in all cases. Therefore, unless otherwise indicated, the numerical parameters set forth in the following specification and the attached claims are approximate values ​​that vary according to the desired performance to be obtained by the present invention. At least it is not intended to limit the application of the doctrine of equivalents to the scope of the claims, and each numerical parameter should at least be interpreted according to the number of reported significant figures and by applying ordinary rounding techniques.

[0043] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values ​​set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0044] When a numerical range is disclosed herein, the above range is deemed to be continuous and includes the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise indicated, all ranges disclosed herein should be understood to include any and all sub-ranges included therein. For example, a specified range from "1 to 10" should be deemed to include any and all sub-ranges between a minimum of 1 and a maximum of 10. Exemplary sub-ranges of ranges 1 to 10 include, but are not limited to, 1 to 6.1, 3.5 to 7.8, 5.5 to 10, etc.

[0045] See also Figure 1 , which is a schematic flow chart of a method for forming a gas-sensitive film according to an exemplary embodiment of the present invention. The present invention discloses a method for forming a gas-sensitive film, which comprises the following steps:

[0046] S101: providing a photosensitive solution and a gas-sensitive solution; the photosensitive solution comprises a photoacid generator or a photosensitive cross-linking agent; the gas-sensitive solution comprises a nanomaterial encapsulated with a ligand.

[0047] Exemplarily, the photosensitive solution also includes a target solvent; the gas-sensitive solution also includes the target solvent; the target solvent is a solvent capable of dissolving the ligand. The above step S101 can be specifically described as the preparation of a photosensitive solution and the preparation of a gas-sensitive solution, wherein the preparation process of the photosensitive solution is as follows: dissolving the photosensitive substance in the target solvent to obtain a photosensitive solution of a preset concentration. Optionally, the concentration of the photosensitive solution can be set as needed. The target solvent can specifically be a pure solvent, for example, the target solvent can be a pure toluene.

[0048] Photosensitive substances are a type of organic molecules that will undergo a chemical reaction after being irradiated by ultraviolet light, electron beams, or pulsed lasers. The molecules that have reacted will react chemically with the ligands of nanomaterials with specific ligands, which will reduce the stability of the nanomaterials in the solvent and make them no longer dispersed in the solvent, thereby achieving pattern solidification of the material after irradiation. This type of photosensitive substance includes two major categories. The first category is photoacid generators:

[0049] A photoacid generator is a kind of material that can generate acidic protons (H +) substances, such as 2,4-bis(trichloromethyl)-6-p-methoxyphenylvinyl-S-triazine (abbreviated as MBT), 1-diazo-2-naphthol-4-sulfonic acid (abbreviated as DNS). Taking 2,4-bis(trichloromethyl)-6-p-methoxyphenylvinyl-S-triazine (abbreviated as MBT) as an example, please refer to Figure 2 , which shows a schematic diagram of the reaction principle of a photoacid generator under ultraviolet light. When the photoacid generator MBT (which can also be written as HR, where H represents hydrogen and R represents other organic groups in MBT) is irradiated with light of a certain wavelength, a chemical reaction will occur to produce acidic protons (H + ), proton (H + ) reacts with the surface ligands (ionic ligands) of the nanoparticles (i.e., the nanoparticles in the nanomaterial) to strip off the surface ligands. Since the nanoparticles rely on the surface ligands to be dispersed in the target solvent, when the surface ligands are stripped off, the nanoparticles cannot be redispersed in the target solvent.

[0050] Photosensitive crosslinkers are molecules containing at least two photo-crosslinkable azide or carbene groups, such as bis(4-azido-2,3,5,6-tetrafluorobenzoic acid) glycol ester (abbreviated as 2bx), ((1E,4E)-1,5-bis(4-azido-2,3,5,6-tetrafluorophenyl)-1,4-pentadien-3-one) (abbreviated as BTO), N,N-dimethyl-N,N-trimethylenebis(4-azido-2,3,5,6-tetrafluorobenzamide) ammonium iodide (abbreviated as TAI), etc. See Figure 3 , which shows a schematic diagram of the reaction principle of a photosensitive crosslinker under ultraviolet light in the present application. After ultraviolet irradiation, the photosensitive crosslinker forms reactive nitrene / carbene free radicals, which react with organic molecules with long-chain carbon-hydrogen structures (organisms containing at least 6 carbon atoms), such as oleic acid and oleylamine. The nitrene / carbene free radicals and organic molecules with long-chain carbon-hydrogen structures will undergo carbon-hydrogen insertion reactions, so that the nanoparticles are cross-linked through the ligands and the nitrene / carbene free radicals, reducing the overall solubility.

[0051] After the photosensitive substance is combined with the nano gas-sensitive material to form a film on a substrate prepared with a sensor, after being irradiated with light of a certain wavelength and dosage, the photoacid generator or the photosensitive cross-linking agent can react with the nano material to strip off or cross-link part of the ligands on the surface of the nano material, and the pattern of the exposed area is no longer dispersed in the solvent that can be dispersed when not exposed to light. The substrate is immersed in the solvent originally used for dispersion to remove the unexposed part of the pattern, selectively leaving the exposed area, and depositing the gas-sensitive material on the sensor to complete the preparation of the sensor. Not only is the manufacturing efficiency high, but also the gas-sensing performance of the sensor is improved.

[0052] Exemplarily, the preparation process of the gas-sensitive solution is as follows: the nanomaterials wrapped with ligands are dispersed in a target solvent to obtain a gas-sensitive solution. Optionally, the concentration of the gas-sensitive solution can be set as required. The target solvent can specifically be a pure solvent, for example, the target solvent can be a pure toluene.

[0053] The nanomaterials include nanometals and their oxides, II-VI nanocrystals and III-V nanocrystals; the nanometal oxides include but are not limited to gold, platinum, palladium, rhodium, zinc oxide, indium oxide, tungsten oxide, tin oxide, titanium oxide, copper oxide, nickel oxide or iron oxide and one or more combinations of nanometals and their oxides, and the II-VI nanocrystals include but are not limited to one or more combinations of CdS, CdSe, CdTe, ZnS, ZnSe and ZnTe. The III-V nanocrystals include but are not limited to one or more combinations of InP, InAs, InN, GaAs, GaN, GaP, AlN, AlP and AlAs. The gas-sensing properties of the device can be realized. The shapes of the nanomaterials include but are not limited to one or more combinations of spheres, rods, wires, sheets, tubes and flowers.

[0054] The surface of these nanomaterials is coated with ligands, so that they can be stably dispersed in certain polar or non-polar solvents (which type of solvent is suitable for dispersion according to the specific ligand). Nanoparticles coated with long-chain hydrocarbon organic ligands (nanoparticles coated with oleic acid and oleylamine, the hydrocarbon chain of the organic ligand includes one or more substituents of carboxyl, amine, phosphine, phosphonic acid, quaternary ammonium salt, sulfonate, and thiol.) can be dissolved in non-polar solvents (such as toluene, n-hexane, cyclohexane, n-octane, butyl acetate, one or more combinations). Nanoparticles with anionic ligands on the surface are dissolved in polar solvents (such as dimethyl sulfoxide, formamide, N,N-dimethylformamide, N-methylformamide, acetonitrile, acetone, and one or more combinations of water.), so that the nanomaterials rely on ligands to dissolve in the developer (developer solvent refers to the solvent in which the film-forming material can be dispersed before illumination, and in the embodiment of the present application, it can also refer to the target solvent). The photosensitive solution and the gas-sensitive solution are mixed in a suitable ratio, and the mixed solution is formed into a film on the substrate and directly photolithographically formed, and the photosensitive molecules react with the ligands on the surface of the nanoparticles so that the nanoparticles can no longer be dispersed in the developer solvent. For example, the mass ratio of the photosensitive substance to the nanomaterial in the mixed solution can be 1wt% to 40wt%.

[0055] For example, the hydrocarbon organic ligand can be an organic body containing at least 6 carbon atoms, such as oleic acid, oleylamine, etc. The anionic ligand can be divided into two categories. One category is metal-containing anions: such as metal halide anions, with the chemical formula MX n m-, where M represents a metal atom, X represents a halogen atom, n represents the stoichiometric number of the halogen atom (such as 3 or 4), and m represents the charge of the anion (such as 1 or 2), for example CdCl3 - and CdCl4 2- .

[0056] Metal chalcogen anion, chemical formula MCh n m- , where M represents the metal atom, Ch represents the chalcogen atom, n represents the stoichiometric number of the chalcogen atom (such as 2, 3, 4, 5, or 6), and m represents the charge of the anion (such as 2, 3, or 4), for example CdTe2 2- 、Sn2S6 4- 、AsS3 3- and SnS4 4- .

[0057] Metal oxide anion, chemical formula MO z y , where M represents the metal atom, z represents the stoichiometric number of the oxygen atom (such as 4), and y represents the charge of the anion (such as 2), for example MoO4 2- . Also included are metal phosphorus oxides, such as P2W 18 O 62 6- and PMo 12 O 40 3- .

[0058] The other type is metal-free anions: such as oxide anions of non-metallic sulfur, phosphorus, nitrogen and carbon, such as sulfide anions (SO3 2- ), phosphate anion (PO4 2- ), tetrafluoroborate anion (BF4 - ) and OCN - Anion. The chemical formula of halide anion is X u m- , for example: Cl - .

[0059] Exemplarily, the nanomaterial coated with ligands can be synthesized, such as forming ligands on the surface of the nanomaterial by chemical replacement, or directly further processing the nanomaterial coated with ligands on the surface. It can also be directly purchased as a finished product. Similarly, the photosensitive substance can also be directly purchased or synthesized, which is not limited here.

[0060] It should be noted that different photosensitive substances have different ligand types for corresponding reactions. For example, the photoacid generator can generate protons under ultraviolet irradiation, and it usually reacts with ionic ligands. Therefore, when the photosensitive solution is a solution configured based on the photoacid generator, the ligand in the corresponding mixed gas-sensitive solution should be a nanomaterial of ionic ligands. The photosensitive cross-linker can generate nitrene / carbene free radicals under ultraviolet irradiation, and it usually reacts with organic molecules with long-chain hydrocarbon structures. Therefore, the photosensitive solution is a solution configured based on the photosensitive cross-linker, and the ligand in the corresponding mixed gas-sensitive solution should be a nanomaterial of long-chain hydrocarbon organic ligands.

[0061] S102: Mixing the photosensitive solution and the gas sensitive solution in a preset ratio to obtain a mixed solution.

[0062] Exemplarily, a mixed solution can be obtained by mixing the above-mentioned photosensitive solution and gas-sensitive solution according to a preset volume ratio. Specifically, 2bx can be dissolved in toluene to prepare a photosensitive solution with a concentration of 1 to 40 mg / ml (i.e., 1 to 40 mg of 2bx is contained in each ml of the photosensitive solution), zinc oxide nanoparticles coated with oleic acid ligands on the surface are dissolved in toluene to obtain a gas-sensitive solution with a concentration of 1 to 200 mg / ml, and the photosensitive solution is mixed with the gas-sensitive solution to obtain a mixed solution, wherein the mass ratio of the photosensitive substance to the nanomaterial in the mixed solution is 1wt% to 40wt%. MBT can also be dissolved in toluene to prepare a photosensitive solution with a concentration of 1 to 40 mg / ml (i.e., 1 to 40 mg of MBT is contained in each ml of the photosensitive solution), indium oxide nanoparticles coated with oleic acid ligands on the surface are dissolved in toluene to obtain a gas-sensitive solution with a concentration of 1 to 200 mg / ml, and the photosensitive solution is dispersed in the gas-sensitive solution, and the volume ratio of the two is 10:1-1:10 to obtain a mixed solution. Other photosensitive substances, target solvents and nanomaterials mentioned above may also be selected, without limitation herein.

[0063] S103: After coating the mixed solution on the surface of the target substrate, pattern curing treatment is performed on the mixed solution under ultraviolet light to obtain a gas-sensitive film on the target substrate.

[0064] Exemplarily, after coating the mixed solution on the surface of the target substrate 1 in step S103, pattern curing the mixed solution under ultraviolet light to obtain the gas sensitive film 3 on the target substrate 1 includes: coating the mixed solution on the target substrate 1 (such as Figure 4 Based on a preset mask, the mixed solution on the surface of the target substrate 1 is subjected to UV curing to obtain an initial gas-sensitive film 2, and the resultant can be as shown. Figure 5The structure shown in FIG. 2 is used to remove the uncured area of ​​the initial gas-sensitive film 2 to obtain a gas-sensitive film 3 located on the target substrate 1, and the gas-sensitive film 3 can be obtained as shown in FIG. Figure 6 Optionally, depending on the type of gas sensor, the target substrate 1 may be Figure 4 The structure shown, i.e., including a substrate 11 and an interdigital transducer 12 located on the substrate 11, can also be an electrochemical sensor, then the target substrate 1 includes a substrate and a working electrode located thereon, and subsequently, the gas-sensitive film 3 is also formed on the working electrode, which is not limited here. Optionally, the developer can be the target solvent. For example, when the target solvent is toluene, toluene can be used here to remove the uncured area in the initial gas-sensitive film 2. Of course, if the type of the target solvent is ethanol, the developer can also be ethanol at this time. Optionally, the developer is not limited to the target solvent mentioned above, and can also be other non-target solvents, as long as it can dissolve the uncured part of the gas-sensitive material. Optionally, the range of ultraviolet light is 183nm~405nm, and a suitable ultraviolet wavelength can be selected according to the specific type of gas-sensitive molecules.

[0065] For example, see Figure 7 , which is a SEM image of a gas-sensitive film after pattern curing according to an exemplary embodiment of the present invention. Based on the above steps S101-S103, a gas-sensitive film can be formed on the target substrate 1. Figure 7 The pattern array shown, Figure 7 The three light grey diamonds in the figure are the pattern array of the formed gas sensitive film.

[0066] The embodiments of the present application combine photosensitive molecules (photosensitive molecules of the photoacid generator type or photosensitive cross-linking agent type) with nano gas-sensitive materials to obtain a gas sensing material that can be directly photolithographically solidified in a pattern. A thin film of the gas-sensitive material can be deposited on a sensor substrate by spin coating, spraying, scraping, or immersion pulling, and the material film can be directly exposed and developed to realize the preparation of a gas sensor on a substrate prepared with a sensor.

[0067] On the other hand, the present application further discloses a method for manufacturing a gas sensor, which comprises the following steps: forming the gas sensitive film 3 on the sensitive material area of ​​the gas sensor according to the above-mentioned method for forming the gas sensitive film 3 .

[0068] For example, see Figure 6 The semiconductor structure includes a substrate 11 and an IDT 12 located on the substrate 11; the gas sensitive film 3 is located on the surface of the IDT. Optionally, the gas sensor can also be an electrochemical sensor, and then the gas sensitive film 3 is also formed on the working electrode.

[0069] On the other hand, the present application also discloses a gas sensor, which is prepared by the above-mentioned manufacturing method.

[0070] The following two specific embodiments further illustrate the technical effects of the present application:

[0071] Example 1

[0072] 2bx was dissolved in toluene to prepare a photosensitizing solution with a concentration of 25 mg / ml, and the photosensitizing solution was uniformly mixed with a gas-sensing solution (concentration of 100 mg / ml) of zinc oxide nanoparticles with oleic acid ligands coated on the surface dispersed in toluene at a volume ratio of 1:1 to obtain a mixed solution.

[0073] Provide as Figure 4 In the semiconductor structure shown, the mixed solution is coated on the interdigital transducer 12 by spin coating. The spin coating speed is 2000 rpm and the time is 50 s. The thickness of the gas-sensitive film obtained by spin coating is 50 nm.

[0074] 254nm ultraviolet light was irradiated through the transparent area of ​​the mask to the gas-sensitive film below for 2 minutes, so that the 2bx molecules cross-linked the zinc oxide nanoparticles to destroy their solvent dispersibility. Then, the substrate was immersed in toluene for 1 minute to disperse and remove the unexposed area, and the substrate surface was blown dry after being taken out to obtain a gas sensor with a zinc oxide nanoparticle film selectively deposited at the interdigital transducer 12 (see Figure 6 ).

[0075] By testing the gas sensing performance of the gas sensor prepared in Example 1, the following results can be obtained: Figure 7 From the results shown, it can be seen that the resistance value and response of the gas sensor under different nitrogen dioxide concentrations (such as 5ppm, 10ppm, 15ppm) are different. Specifically, when no nitrogen dioxide is introduced, the resistance value of the gas sensor response of Example 1 is 25MΩ. After 5ppm of nitrogen dioxide is introduced, the maximum resistance value of the gas sensor response of Example 1 is 5GΩ, and the response S is 200 (usually the response S=Rg / Ra, Rg represents the resistance when the test gas is introduced, and Ra represents the resistance when the balance gas air is introduced). After 10ppm of nitrogen dioxide is introduced, the maximum resistance value of the gas sensor response of Example 1 is 12GΩ, and the response S is 480; after 15ppm of nitrogen dioxide is introduced, the maximum resistance value of the gas sensor response of Example 1 is 20GΩ, and the response S is 880. It can be seen that with the increase of nitrogen dioxide concentration, the resistance value and response of the gas sensor response will increase, indicating that the gas sensor can show good gas-sensitive properties to nitrogen dioxide gas.

[0076] Example 2

[0077] MBT was dissolved in toluene at a concentration of 10 mg / ml to prepare a photosensitizing solution with a concentration of 10 mg / ml, and the photosensitizing solution was uniformly mixed with a gas-sensitive solution (concentration of 40 mg / ml) of indium oxide nanoparticles with oleic acid ligands on the surface dispersed in toluene at a volume ratio of 1:1 to obtain a mixed solution.

[0078] Provide as Figure 4 In the semiconductor structure shown, the mixed solution is coated on the interdigital transducer 12 by spin coating. The spin coating speed is 1000 rpm and the time is 40 s. The thickness of the gas-sensitive film obtained by spin coating is 40 nm.

[0079] 365nm ultraviolet light was irradiated through the transparent area of ​​the mask to the gas-sensitive film below for 2 minutes. The protons generated by the light stripped off the oleic acid ligands on the surface of the nanoparticles, making them no longer dispersed in the toluene solvent. Then, the substrate was immersed in toluene for 1 minute to wash away the unexposed area, and the substrate surface was blown dry after being taken out to obtain a gas sensor with indium oxide nanoparticle film selectively deposited at the interdigital transducer (see Figure 6 ).

[0080] The above description is only an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for forming a gas-sensitive film, characterized in that: The following steps are involved: A photosensitive solution and a gas-sensitive solution are provided; the photosensitive solution comprises a photoacid generator or a photosensitive crosslinker; the gas-sensitive solution comprises a nanomaterial encapsulated with a ligand; Mixing the photosensitive solution and the gas-sensitive solution in a preset ratio to obtain a mixed solution; After the mixed solution is coated on the surface of the target substrate, the mixed solution is subjected to pattern curing treatment under ultraviolet light conditions to obtain a gas-sensitive film on the target substrate.

2. The forming method according to claim 1, characterized in that: Under the ultraviolet light condition, the photoacid generator or the photosensitive crosslinker can react with the nanomaterial to strip or crosslink part of the ligands on the surface of the nanomaterial; The nanomaterials are dissolved in the developer by means of ligands.

3. The forming method according to claim 2, characterized in that: After coating the mixed solution on the surface of the target substrate, the mixed solution is subjected to pattern curing treatment under ultraviolet light conditions to obtain a gas-sensitive film on the target substrate, comprising: The mixed solution is coated on the surface of the target substrate by spin coating, spray coating, blade coating or dip-pull coating; Based on a preset mask, the mixed solution on the surface of the target substrate is subjected to ultraviolet curing treatment to obtain an initial gas-sensitive film; The developer is used to remove the uncured area in the initial gas-sensitive film to obtain a gas-sensitive film on the target substrate.

4. The forming method according to claim 3, characterized in that: The photosensitive solution also includes a target solvent; The gas-sensitive solution also includes the target solvent; The target solvent is a solvent that can dissolve the ligand.

5. The forming method according to any one of claims 1 to 4, characterized in that: The nanomaterial includes any one of metals and their oxides, II-VI group nanocrystals and II IV group nanocrystals; The nano metal and its oxide include one or a combination of two or more of gold, platinum, palladium, rhodium, zinc oxide, indium oxide, tungsten oxide, tin oxide, titanium oxide, copper oxide, nickel oxide or iron oxide; The II-VI group nanocrystals include CdS, CdSe, CdTe, ZnS, ZnSe or ZnTe; the III-V group nanocrystals include InP, InAs, InN, GaAs, GaN, GaP, AlN, AlP or AlAs.

6. The forming method according to any one of claims 1 to 4, characterized in that: Photoacid generators can generate acidic protons under ultraviolet light irradiation; The photosensitive crosslinking agent contains at least two photo-crosslinkable azide groups or carbene groups.

7. The forming method according to any one of claims 1 to 4, characterized in that: The ligand includes a hydrocarbon organic ligand or an anionic ligand; the hydrocarbon organic ligand is an organic body containing at least 6 carbon atoms.

8. A method for manufacturing a gas sensor, characterized in that: The following steps are involved: The gas sensitive film is formed on a sensitive material region of a gas sensor according to the method for forming a gas sensitive film as claimed in any one of claims 1 to 7.

9. The manufacturing method according to claim 8, characterized in that: The gas sensor comprises a substrate and an interdigital transducer located on the substrate; The gas sensitive film is located on the surface of the interdigital transducer.

10. A gas sensor, characterized in that: The invention is prepared by the manufacturing method according to claim 8.

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