Gas sensor and method of manufacturing the same

Abstract

The application relates to a gas sensor and a preparation method thereof, and relates to the technical field of sensors. The preparation method of the gas sensor comprises the following steps: mixing gas-sensitive particles and photoresist to obtain gas-sensitive photoresist mixed material; providing a wafer, wherein the wafer comprises a plurality of micro-sensing areas; spin coating the gas-sensitive photoresist mixed material on the wafer; patterning the gas-sensitive photoresist mixed material to reserve the gas-sensitive photoresist mixed material in the micro-sensing areas to form an initial gas-sensitive layer; and removing the photoresist in the initial gas-sensitive layer to reserve the gas-sensitive particles in the initial gas-sensitive layer to form a gas-sensitive layer of the gas sensor. The preparation method of the gas sensor realizes accurate loading of the gas-sensitive particles into the specified micro-heating area, and is beneficial to the common improvement of the production efficiency and the yield of the gas sensor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sensors, in particular to a gas sensor and a preparation method thereof. BACKGROUND

[0002] With the rapid development of the Internet of Things and the advent of the 5G era, developing small-size and portable gas sensors has become a current technical trend. For example, a gas sensor based on a Micro Electro Mechanical System (MEMS) is based on micro-nano processing technology, which miniaturizes nano functional materials and device structures, thereby improving the electronic integration, intelligence, low power consumption, and low cost of the sensor, and continuously expanding the product application space of the gas sensor.

[0003] At present, one of the key technologies for manufacturing gas sensors is to accurately load the sensing material to the specified micro-heating area. However, the existing technology is difficult to achieve uniform deposition of the sensing material film, and the production equipment is complex and the cost is high, which is an urgent difficulty for mass production of gas sensors.

[0004] Therefore, how to realize the common improvement of the production efficiency and the yield of the gas sensor is a problem to be solved. SUMMARY

[0005] Therefore, it is necessary to provide a gas sensor and a preparation method thereof to effectively improve the production efficiency and the yield of the gas sensor.

[0006] In order to achieve the above-mentioned purpose, the embodiments of the present application provide a preparation method of a gas sensor, comprising: mixing gas sensitive particles and photoresist to obtain a gas sensitive photoresist mixed material; providing a wafer, the wafer comprising a plurality of micro-sensing regions; spin coating the gas sensitive photoresist mixed material on the wafer, the gas sensitive photoresist mixed material covering at least the micro-sensing regions; patterning the gas sensitive photoresist mixed material to retain the gas sensitive photoresist mixed material located in the micro-sensing regions to form an initial gas sensitive layer; removing the photoresist in the initial gas sensitive layer to retain the gas sensitive particles in the initial gas sensitive layer to form a gas sensitive layer of the gas sensor.

[0007] The preparation method of the gas sensor mixes the photoresist and the gas sensitive particles to form a gas sensitive photoresist mixed material. Therefore, after the gas sensitive photoresist mixed material is spin-coated on the wafer containing a plurality of micro-sensing areas, the gas sensitive photoresist mixed material film outside the micro-sensing area can be removed by using a patterning process to retain the gas sensitive photoresist mixed material film in the micro-sensing area, that is, to obtain an initial gas sensitive layer. Finally, the photoresist in the initial gas sensitive layer is removed to obtain a gas sensitive layer, which realizes the accurate loading of the gas sensitive particles to the micro-sensing area. The micro-sensing area is, for example, a specified micro-heating area. Therefore, the preparation method of the gas sensor can accurately load the gas sensitive particles to the specified micro-heating area by spin-coating the gas sensitive photoresist mixed material and then removing the photoresist, thereby eliminating the complex and time-consuming glue dropping or dispensing steps in the traditional gas sensitive particle deposition process, and thus facilitating the improvement of the production efficiency of the gas sensor.

[0008] In addition, compared with the glue dropping or dispensing needle head contact coating, the above-mentioned preparation method of the gas sensor does not need to use the glue dropping or dispensing steps, thereby effectively overcoming the problems of film rupture, poor thickness uniformity of the gas sensitive material, and low efficiency, and thus facilitating the improvement of the yield of the gas sensor.

[0009] Optionally, the mass percentage concentration of the gas sensitive particles in the gas sensitive photoresist mixed material is 4wt%-5wt%.

[0010] Optionally, mixing the gas sensitive particles and the photoresist includes: mixing the gas sensitive particles and the photoresist by mechanical stirring.

[0011] Optionally, the stirring rate of the mechanical stirring includes: 800rpm±100rpm; and / or, the stirring time of the mechanical stirring is not less than 2 hours.

[0012] Optionally, spin-coating the gas sensitive photoresist mixed material on the wafer includes: repeatedly spin-coating the gas sensitive photoresist mixed material on the wafer multiple times.

[0013] Optionally, the spin-coating rate of the gas sensitive photoresist mixed material on the wafer in a single spin-coating process includes: 600rpm±100rpm.

[0014] Optionally, spin-coating the gas sensitive photoresist mixed material on the wafer further includes: pre-baking the spin-coated gas sensitive photoresist mixed material; wherein the pre-baking temperature is in the range of 100℃±20℃.

[0015] Optionally, the gas-sensitive photoetching mixed material is patterned to reserve the gas-sensitive photoetching mixed material in the micro-sensing region to form an initial gas-sensitive layer, comprising: exposing and developing the gas-sensitive photoetching mixed material based on a patterned mask, wherein the patterned mask is used to define the micro-sensing region; and removing the gas-sensitive photoetching mixed material outside the micro-sensing region to reserve the gas-sensitive photoetching mixed material in the micro-sensing region to form the initial gas-sensitive layer.

[0016] The preparation method of the gas sensor above removes the gas-sensitive photoetching mixed material film outside the micro-sensing region by an exposing and developing process based on a patterned mask to reserve the gas-sensitive photoetching mixed material film in the micro-sensing region, that is, to obtain the initial gas-sensitive layer. The preparation method realizes the deposition of the patterned gas-sensitive material film in the micro-sensing region in a large area through only one step of the exposing and developing process, and also ensures that the gas-sensitive characteristics of the gas-sensitive particles are not affected.

[0017] Optionally, the photoresist includes a positive photoresist; and the photoresist removing method in the initial gas-sensitive layer includes: baking the wafer after the initial gas-sensitive layer is formed by using a tube furnace; wherein the baking temperature is in the range of 600℃±100℃, and the baking time is not less than 6 hours.

[0018] Based on the same inventive concept, the embodiments of the present application also provide a gas sensor obtained by using the preparation method according to any one of the preceding solutions.

[0019] The gas sensor above is obtained by using the preparation method according to any one of the preceding solutions, and realizes the accurate loading of the gas-sensitive particles to the micro-sensing region. The micro-sensing region is, for example, a designated micro-heating region, and therefore the gas sensor above realizes the accurate loading of the gas-sensitive particles to the designated micro-heating region, and eliminates the complex and time-consuming steps of glue dropping or glue dispensing in the traditional deposition process of the gas-sensitive particles, thereby facilitating the improvement of the production efficiency of the gas sensor.

[0020] In addition, compared with the problems of film rupture, poor thickness uniformity of the gas-sensitive material and low efficiency caused by the contact of the glue dropping or glue dispensing needle with the coating, the gas sensor above does not need to use glue dropping or glue dispensing, and therefore can effectively overcome the problems, thereby facilitating the improvement of the yield of the gas sensor. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0022] Figure 1 Figures (a), (b), and (c) are schematic diagrams of the gas sensor structure after the gas-sensitive layer is formed using different processes in the related technologies.

[0023] Figure 2 This is a flowchart illustrating a method for fabricating a gas sensor according to one embodiment;

[0024] Figure 3 Figure (a) is a schematic diagram of a wafer containing multiple gas sensors provided in one embodiment; Figure 3 Figure (b) is Figure 3 Figure (a) shows a magnified schematic diagram of the gas-sensitive layer in a gas sensor under an electron microscope.

[0025] Figure 4 Figures (a) and (b) in the figure are magnified schematic diagrams of the gas-sensitive layer in a gas sensor provided in one embodiment under an electron microscope at different magnifications;

[0026] Figure 5 Figures (a), (b), and (c) in the figure represent the implementation of an embodiment using... Figure 2 The resistance response changes of three different gas sensors obtained by the preparation method shown are illustrated.

[0027] Figure 6 This is a flowchart of an initial gas-sensitive layer formation method provided in one embodiment.

[0028] Explanation of reference numerals in the attached figures:

[0029] 10 - Wafer; 20 - Gas sensor; 21 - Gas-sensitive layer. Detailed Implementation

[0030] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0032] Reference to "an embodiment" herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the disclosure. The appearances of the phrase "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. It is expressly understood that any of the embodiments described herein can be incorporated into any other embodiment.

[0033] It is to be understood that the terms "first", "second", "third", "fourth", and the like in the description and in the claims, if any, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of use in either order.

[0034] It is to be understood that the "connection" in the following embodiments, if the circuit, module, unit and the like connected between each other have the transmission of electrical signal or data, should be understood as "electrically connected", "communicatively connected" and the like.

[0035] As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. It is to be understood that the terms "comprise / comprising", "have / having" or "include / including" or any variation thereof, specify the presence of the stated features, integers, steps, operations, components, parts, or combinations of them, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations of them.

[0036] With the rapid development of microfabrication technology, in the past few decades, MEMS-based gas sensors have significantly reduced device size and power consumption. For example, micro-electro-mechanical system (MEMS) based gas sensors are based on micro-nano processing technology, which miniaturizes nano functional materials and device structures, thereby improving the electronic integration, intelligence, low power consumption, and low cost of sensors, and continuously expanding the product application space of gas sensors.

[0037] A complete gas sensor industry chain includes chip design and manufacturing, materials research and development, material coating, device packaging and testing, module assembly, and application scenarios. While China's gas sensor industry, especially the downstream segments such as device packaging, testing, modules, and application scenarios, is developing rapidly, the upstream innovation-intensive technologies, such as chip design and manufacturing, and materials research and development, particularly wafer-level material coating, are progressing relatively slowly, lagging significantly behind foreign counterparts. Increasing resource investment in upstream segments is crucial for enhancing the core competitiveness of domestically produced gas sensors.

[0038] One of the key technologies in manufacturing gas sensors lies in the precise loading of sensing materials onto designated micro-heated areas, which remains a challenging task. Existing technologies struggle to achieve uniform deposition of thin-film gas-sensitive materials, and the complex and costly production equipment presents a pressing obstacle to the wafer-level mass production of gas sensors.

[0039] Currently, there are several main solutions to the above problems: The first solution is to use specialized instruments (such as micro-manipulators) to deposit sensing materials onto the micro-sensing area via dispensing or spraying. The drawback of this solution is its very low yield (approximately 60%). For example: Figure 1 As shown in Figure (a), contact between the dispensing or spraying needle and the coating causes the suspended silicon nitride film to break; as Figure 1 As shown in Figure (b), the amount of adhesive dispensed cannot be precisely controlled; as Figure 1 As shown in Figure (c), the gas-sensitive material exhibits poor thickness uniformity, among other issues. Furthermore, wafer-level dispensing or spraying requires specialized and expensive equipment (such as micro-robotics), resulting in low production efficiency and hindering mass production. The second approach involves micro-patterned, self-assembled monolayers with hydrophobic properties: before applying the gas-sensitive material, a hydrophobic monolayer is grown on the non-sensing region of the microheater chip to guide the gas-sensitive material to spontaneously flow towards the hydrophilic sensing region. Without a hydrophobic monolayer, even when using specialized equipment (such as micro-robotics) to deposit the sensing material onto the micro-sensing region via dispensing or spraying, the gas-sensitive material easily diffuses, leading to contact with the pads and causing short circuits or leakage. While this approach may effectively solve the problem of "inability to precisely control the amount of dispensing," it fails to effectively address issues such as "fracture of the suspended silicon nitride film due to contact between the dispensing or spraying needle and the coating," "poor uniformity of the gas-sensitive material thickness," and low efficiency. The third approach involves fabricating nanoscale channels: these consist of silicon dioxide nanoparticles defined by interference photolithography on the surface of a planar silicon substrate. The specific steps are: patterning using photoresist and photolithography, followed by spin-coating self-assembly of colloidal silicon dioxide. The photoresist is then removed by high-temperature calcination, leaving open nanochannels. While this approach allows for patterning of nanoparticles, it cannot be used to precisely load sensing materials into specific micro-heated areas.

[0040] Therefore, how to realize the common promotion of the production efficiency and the yield of the gas sensor is an urgent problem to be solved.

[0041] In view of the deficiencies of the prior art described above, the purpose of the present application is to provide a gas sensor and a preparation method thereof, so as to effectively improve the production efficiency and the yield of the gas sensor.

[0042] Please refer to Figure 2 The embodiment of the present application provides a preparation method of a gas sensor, comprising:

[0043] S10: mixing the gas sensitive particles with the photoresist to obtain a gas sensitive photoresist mixed material;

[0044] S20: providing a wafer, the wafer comprising a plurality of micro sensing areas;

[0045] S30: spin coating the gas sensitive photoresist mixed material on the wafer, the gas sensitive photoresist mixed material covering at least the micro sensing areas;

[0046] S40: patterning the gas sensitive photoresist mixed material to reserve the gas sensitive photoresist mixed material in the micro sensing areas to form an initial gas sensitive layer;

[0047] S50: removing the photoresist in the initial gas sensitive layer to reserve the gas sensitive particles in the initial gas sensitive layer to form a gas sensitive layer of the gas sensor.

[0048] It should be noted that the micro sensing area may be, for example, a designated micro heating area. The micro sensing area can be determined according to the number and setting position of the gas sensor.

[0049] The preparation method of the above gas sensor adopts the method of mixing the photoresist with the gas sensitive particles to form the gas sensitive photoresist mixed material, so that after spin coating the gas sensitive photoresist mixed material on the wafer comprising a plurality of micro sensing areas, the film of the gas sensitive photoresist mixed material outside the micro sensing area can be removed by using the patterning process to reserve the film of the gas sensitive photoresist mixed material in the micro sensing area, that is, to obtain the initial gas sensitive layer, and finally the photoresist in the initial gas sensitive layer is removed to obtain the gas sensitive layer, which realizes the accurate loading of the gas sensitive particles to the micro sensing area. The micro sensing area is, for example, a designated micro heating area, so that the above preparation method of the gas sensor can accurately load the gas sensitive particles to the designated micro heating area by spin coating the gas sensitive photoresist mixed material and then removing the photoresist, so as to save the steps of complex and time-consuming glue dropping or glue dispensing in the traditional deposition process of the gas sensitive particles, thereby facilitating the improvement of the production efficiency of the gas sensor.

[0050] In addition, compared with the contact coating of dispensing or spraying glue needle, the above-mentioned gas sensor preparation method does not need to use the dispensing or spraying step, so as to effectively overcome the problems of film rupture, poor thickness uniformity of gas sensitive material and low efficiency, thereby facilitating the improvement of the yield of the gas sensor.

[0051] After the gas sensitive layer of the gas sensor is prepared on the wafer by using the preparation method provided in the embodiments of the present disclosure, referring to FIG. 1(a), the preparation of the gas sensitive layer in a large area range can be realized on the wafer, such as the micro-sensing area of the plurality of gas sensors arranged in an array. Referring to FIG. 1(b), after the gas sensitive layer 21 is prepared by using the preparation method provided in the embodiments of the present disclosure, the shape of the gas sensitive layer 21 is regular and the uniformity is good, and the problems caused by the contact coating of the dispensing or spraying glue needle do not occur. Referring to FIG. 1(a) and FIG. 1(b), after the gas sensitive layer 21 is magnified and imaged under an electron microscope at different magnifications, it can be clearly seen that the uniformity of the gas sensitive layer 21 obtained by using the preparation method of the gas sensor provided in the present application is good. Figure 3 Figure 3 Figure 4

[0052] In addition, three gas sensors 20 are randomly selected by cutting / scribing in the wafer 10 shown in FIG. 2(a), and the resistance response change of the device to 100 ppm concentration of ethanol gas at 300°C is tested, and the test results are shown in FIG. 3(a), FIG. 3(b) and FIG. 3(c), respectively. Figure 3 Figure 5 Figure 5 FIG. 3(a), FIG. 3(b) and FIG. 3(c) from left to right respectively show the resistance response change of the three gas sensors to 100 ppm concentration of ethanol gas at 300°C. As can be seen from FIG. 3, the resistance response changes of the three gas sensors are basically consistent, indicating that the uniformity of the gas sensitive performance is good. Therefore, the preparation method of the gas sensor provided in the present application realizes the common improvement of the production efficiency and the yield of the gas sensor. Figure 5

[0053] In step S10, the mass percentage concentration of the gas sensitive particles in the gas sensitive photoresist mixed material can be 4wt%-5wt%. For example, the mass percentage concentration of the gas sensitive particles in the gas sensitive photoresist mixed material can be 4wt%, 4.2wt%, 4.4wt%, 4.6wt%, 4.8wt% or 5wt% and the like.

[0054] Optionally, the gas sensitive particles can be tin dioxide nanoparticles synthesized by a hydrothermal chemical method.

[0055] In some examples, the mixing of the gas sensitive particles and the photoresist includes: mixing the gas sensitive particles and the photoresist by mechanical stirring. ​​​​​​

[0056] Optionally, the stirring rate of the mechanical stirring comprises: 800 rpm ± 100 rpm; and / or, the stirring time of the mechanical stirring is not less than 2 hours. For example, the stirring rate of the mechanical stirring can be 700 rpm, 750 rpm, 800 rpm, 850 rpm, or 900 rpm, and the like. The time of the mechanical stirring can be 2 hours, 2.5 hours, 3 hours, 3.5 hours, or 4 hours, and the like.

[0057] In step S20, the spin-coating of the gas-sensitive photoetching mixed material on the wafer comprises: repeatedly spin-coating the gas-sensitive photoetching mixed material on the wafer for multiple times. For example, the gas-sensitive photoetching mixed material is spin-coated on the wafer for two times. It can be understood that the more the spin-coating times are repeated, the thicker the film of the gas-sensitive photoetching mixed material is obtained. In practical applications, the spin-coating times can be selected according to the thickness of the film of the gas-sensitive photoetching mixed material required by the actual application, and the embodiments of the present application do not limit the spin-coating times.

[0058] Optionally, the spin-coating rate of the gas-sensitive photoetching mixed material on the wafer for a single time comprises: 600 rpm ± 100 rpm. For example, the spin-coating rate of the gas-sensitive photoetching mixed material on the wafer for a single time can be 500 rpm, 550 rpm, 600 rpm, 650 rpm, or 700 rpm, and the like.

[0059] It should be understood that the execution of step S10 and step S20 does not have strict order limitation, step S10 can be executed before step S20, or can be executed after step S20, or step S10 and step S20 can also be executed simultaneously.

[0060] In step S30, the spin-coating of the gas-sensitive photoetching mixed material on the wafer further comprises: pre-baking the gas-sensitive photoetching mixed material after spin-coating. Optionally, the pre-baking temperature is in the range of 100°C ± 20°C. For example, the pre-baking temperature can be 80°C, 90°C, 100°C, 110°C, or 120°C, and the like.

[0061] In step S40, referring to Figure 6 The gas-sensitive photoetching mixed material is patterned to reserve the gas-sensitive photoetching mixed material in the micro-sensing area to form an initial gas-sensitive layer, comprising:

[0062] S401: exposing and developing the gas-sensitive photoetching mixed material based on the patterned mask plate;

[0063] S402: the patterned mask plate is used to define the micro-sensing area;

[0064] S403: removing the gas-sensitive photoetching mixed material in the area outside the micro-sensing area to reserve the gas-sensitive photoetching mixed material in the micro-sensing area to form an initial gas-sensitive layer.

[0065] The preparation method of the gas sensor is based on a patterned mask, and the gas-sensitive photoresist hybrid material film outside the micro-sensing region is removed by an exposure and development process to retain the gas-sensitive photoresist hybrid material film in the micro-sensing region, that is, to obtain an initial gas-sensitive layer. The preparation method realizes the deposition of the patterned gas-sensitive material film in the micro-sensing region by only one step of exposure and development process, and also ensures that the gas-sensitive characteristics of the gas-sensitive particles are not affected.

[0066] Optionally, the photoresist includes a positive photoresist.

[0067] In step S50, the photoresist removal method in the initial gas-sensitive layer includes baking the wafer after the initial gas-sensitive layer is formed by using a tube furnace. Optionally, the baking temperature is in the range of 600 ± 100 ℃, for example, the baking temperature can be 500 ℃, 550 ℃, 600 ℃, 650 ℃ or 700 ℃, etc. The baking time is not less than 6 hours, for example, the baking time can be 6 hours, 6.5 hours, 7 hours, 7.5 hours or 8 hours, etc.

[0068] Here, the wafer after the initial gas-sensitive layer is formed is baked by using a tube furnace, in order to sinter the initial gas-sensitive layer at high temperature. Sintering the initial gas-sensitive layer at high temperature can remove the photoresist in the initial gas-sensitive layer, and ensure that the gas-sensitive particles in the initial gas-sensitive layer are not damaged.

[0069] In some examples, after the gas-sensitive layer and other layer structures are formed, the gas sensor can be obtained by dicing or cutting the wafer.

[0070] Based on the same inventive concept, the embodiments of the present application also provide a gas sensor obtained by using the preparation method according to any one of the preceding solutions.

[0071] The gas sensor is obtained by using the preparation method according to any one of the preceding solutions, which realizes the accurate loading of the gas-sensitive particles into the micro-sensing region. The micro-sensing region is, for example, a designated micro-heating region, so the gas sensor realizes the accurate loading of the gas-sensitive particles into the designated micro-heating region, and eliminates the complex and time-consuming steps of glue dropping or dispensing in the traditional deposition process of the gas-sensitive particles, which is beneficial to improve the production efficiency of the gas sensor.

[0072] In addition, compared with the contact coating of the dispensing or spraying needle, the above-mentioned gas sensor does not need to use dispensing or spraying, so it can also effectively overcome the problems of film rupture, poor thickness uniformity of the gas-sensitive material and low efficiency, which is beneficial to improve the yield of the gas sensor.

[0073] In the description of the specification, each technical feature of the above-described embodiments can be combined with each other, and for the sake of brevity, not all possible combinations of the technical features of the above-described embodiments are described, however, as long as the combination of the technical features does not exist Contradiction, it should be considered within the scope of the present disclosure.

[0074] The above-described embodiments only express several implementation manners of the present disclosure, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present disclosure, a number of modifications and improvements can be made, which are within the protection scope of the present disclosure. Therefore, the protection scope of the patent of the present disclosure should be subject to the appended claims.

Claims

1. A method for preparing a gas sensor, characterized in that, include: Gas-sensitive particles are mixed with photoresist to obtain a gas-sensitive photolithography hybrid material; wherein, the gas-sensitive particles are tin dioxide nanoparticles synthesized by hydrothermal chemical method; A wafer is provided, the wafer comprising multiple microsensing regions; The gas-sensitive photolithography hybrid material is spin-coated onto the wafer, and the gas-sensitive photolithography hybrid material at least covers the micro-sensing region; The gas-sensitive photolithography hybrid material is patterned to retain the gas-sensitive photolithography hybrid material located in the micro-sensing region to form an initial gas-sensitive layer; Remove the photoresist from the initial gas-sensitive layer to retain the gas-sensitive particles in the initial gas-sensitive layer to form the gas-sensitive layer of the gas sensor; The photoresist includes a positive photoresist; the method for removing the photoresist from the initial gas-sensitive layer includes: The wafer after the initial gas-sensitive layer is formed is baked in a tube furnace; wherein the baking temperature ranges from 600℃±100℃ and the baking time is not less than 6 hours; After forming the gas-sensitive layer and other layer structures, the gas sensor is obtained by dicing or cutting a wafer. The mass percentage concentration of the gas-sensitive particles in the gas-sensitive photolithography hybrid material is 4wt%-5wt%.

2. The method for preparing a gas sensor as described in claim 1, characterized in that, The process of mixing gas-sensitive particles with photoresist includes: The gas-sensitive particles are mixed with the photoresist by mechanical stirring.

3. The method for preparing a gas sensor as described in claim 2, characterized in that, The stirring rate of the mechanical stirring is 800 rpm ± 100 rpm; And / or, the stirring time of the mechanical stirring is not less than 2 hours.

4. The method for preparing a gas sensor as described in claim 1, characterized in that, The process of spin-coating the gas-sensitive photolithography hybrid material onto the wafer includes: The gas-sensitive photolithography hybrid material is repeatedly spin-coated onto the wafer.

5. The method for preparing a gas sensor as described in claim 4, characterized in that, The spin coating rate for a single spin coating of the gas-sensitive photolithography hybrid material on the wafer is 600 rpm ± 100 rpm.

6. The method for preparing a gas sensor as described in claim 1 or 4, characterized in that, The process of spin-coating the gas-sensitive photolithography hybrid material onto the wafer further includes: The gas-sensitive photolithography hybrid material after spin coating is pre-baked; wherein the pre-baking temperature ranges from 100℃±20℃.

7. The method for preparing a gas sensor as described in claim 1, characterized in that, The step of patterning the gas-sensitive photolithography hybrid material to retain the gas-sensitive photolithography hybrid material located in the micro-sensing region to form an initial gas-sensitive layer includes: The gas-sensitive photolithography hybrid material is exposed and developed based on a patterned mask; the patterned mask is used to define the micro-sensing region. Remove the gas-sensitive photolithography hybrid material located outside the microsensing region to retain the gas-sensitive photolithography hybrid material located within the microsensing region to form the initial gas-sensitive layer.

8. A gas sensor, characterized in that, It is obtained by the preparation method according to any one of claims 1 to 7.

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