Method for manufacturing a heating assembly and method for manufacturing a gas sensor

Abstract

The application relates to a preparation method of a heating assembly and a preparation method of a gas sensor. The preparation method of the heating assembly comprises the following steps: providing a substrate; forming an electrically-conductive layer on the upper surface layer of the substrate; forming a first insulating layer on the upper surface layer of the electrically-conductive layer, the side wall of the electrically-conductive layer and the upper surface layer of the substrate; forming a side wall structure on the side wall of the first insulating layer, wherein the side wall of the first insulating layer corresponds to the side wall of the electrically-conductive layer; forming a first heating electrode and a second heating electrode on the upper surface layer of the first insulating layer; and wherein the first heating electrode and the second heating electrode are respectively arranged in contact with the end portions of the side wall structure. The preparation method of the heating assembly can save the device design area.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to a method for preparing a heating component and a method for preparing a gas sensor. Background Technology

[0002] With the development of semiconductor technology, gas sensors have emerged. Gas sensors have significant potential for development in fields such as gas sensing components, micro-calorimeters, gas flow meters, infrared light sources, and the collection of minute particles. Gas sensors have advantages such as low heat loss, low heating power, simple manufacturing processes, short response times, and ease of integration with other microelectronic devices, making their applications very wide-ranging.

[0003] Currently, gas sensors are typically integrated with micro-electro-mechanical systems (MEMS) sensing components via heating elements. In traditional technologies, gas sensors are usually constructed by interleaving the heating layer of the heating element with the conductive layer of the sensing element. However, because the heating layer and conductive layer are located on the same plane and a certain distance needs to be maintained between them, traditional technologies suffer from a large device design area. Summary of the Invention

[0004] Therefore, it is necessary to provide a method for fabricating a heating component and a method for fabricating a gas sensor to address the problem of large device design area in existing technologies.

[0005] To achieve the above objectives, in one aspect, the present invention provides a method for preparing a heating component, comprising:

[0006] Provide a base;

[0007] A conductive layer is formed on the upper surface of the substrate;

[0008] A first insulating layer is formed on the upper surface of the conductive layer, the sidewalls of the conductive layer, and the upper surface of the substrate;

[0009] A sidewall structure is formed on the sidewall of the first insulating layer, wherein the sidewall of the first insulating layer corresponds to the sidewall of the conductive layer;

[0010] A first heating electrode and a second heating electrode are formed on the upper surface of the first insulating layer; wherein the first heating electrode and the second heating electrode are respectively disposed in contact with the end of the sidewall structure.

[0011] The above-described method for fabricating a heating component involves forming a conductive layer on the upper surface of the substrate; forming a first insulating layer on the upper surface of the conductive layer, the sidewalls of the conductive layer, and the upper surface of the substrate; forming a sidewall structure on the sidewalls of the first insulating layer, wherein the sidewalls of the first insulating layer correspond to the sidewalls of the conductive layer; and forming a first heating electrode and a second heating electrode on the upper surface of the first insulating layer. The first heating electrode and the second heating electrode are respectively positioned in contact with the ends of the sidewall structure. Because the sidewall structure, which serves as the heating layer of the heating component, is designed on the sidewalls of the conductive layer, it saves on device design area.

[0012] In one embodiment, a sidewall structure is formed on the sidewall of the first insulating layer, including:

[0013] An initial sidewall structure is formed on the surface of the first insulating layer;

[0014] A self-aligned sidewall process is used to remove a portion of the initial sidewall structure to form the sidewall structure; the sidewall structure includes the portion of the initial sidewall structure remaining on the sidewall of the first insulating layer after the portion of the initial sidewall structure has been removed.

[0015] In one embodiment, a conductive layer is formed on the upper surface of the substrate, comprising:

[0016] A first comb structure and a second comb structure are formed on the upper surface of the substrate. The first comb structure and the second comb structure together constitute the conductive layer, wherein the comb teeth of the first comb structure and the comb teeth of the second comb structure are arranged alternately.

[0017] In one embodiment, the first heating electrode includes a first sub-electrode and a second sub-electrode, and the second heating electrode includes a third sub-electrode and a fourth sub-electrode. The formation of the first heating electrode and the second heating electrode on the upper surface of the first insulating layer includes:

[0018] The first sub-electrode, the second sub-electrode, the third sub-electrode, and the fourth sub-electrode are formed on the upper surface of the first insulating layer, wherein,

[0019] The first sub-electrode is in contact with the first sidewall located on the side wall of the first comb structure. The first sidewall is the sidewall structure at the first end of the comb portion of the first comb structure.

[0020] The second sub-electrode is in contact with the second sidewall located on the side wall of the second comb structure, and the second sidewall is the sidewall structure at the second end of the comb tooth portion of the second comb structure;

[0021] The third sub-electrode is in contact with the third sidewall located on the sidewall of the first comb structure, and the third sidewall is the sidewall structure at the second end of the comb portion of the first comb structure.

[0022] The fourth sub-electrode is in contact with the fourth sidewall located on the sidewall of the second comb structure, and the fourth sidewall is the sidewall structure at the first end of the comb tooth portion of the second comb structure.

[0023] On the other hand, this application also provides a method for fabricating a gas sensor, the method comprising:

[0024] Provide a base;

[0025] A conductive layer is formed on the upper surface of the substrate; the conductive layer includes a first comb structure and a second comb structure, wherein the comb teeth of the first comb structure and the comb teeth of the second comb structure are arranged alternately.

[0026] A first insulating layer is formed on the upper surface of the conductive layer, the sidewalls of the conductive layer, and the upper surface of the substrate;

[0027] A sidewall structure is formed on the sidewall of the first insulating layer, wherein the sidewall of the first insulating layer corresponds to the sidewall of the conductive layer;

[0028] The first oxide layer is formed on the upper surface of the first insulating layer and on the surface of the sidewall structure;

[0029] A portion of the first oxide layer is removed to form an initial opening, and a portion of the first oxide layer covering the end of the sidewall structure is removed; wherein the initial opening exposes the upper surface of the first insulating layer;

[0030] The first insulating layer is removed based on the initial opening to form an opening, wherein the opening exposes the upper surface of the conductive layer;

[0031] A first heating electrode and a second heating electrode are formed on the upper surface of the first insulating layer, wherein the first heating electrode and the second heating electrode are respectively disposed in contact with the end of the sidewall structure.

[0032] A first sensing electrode and a second sensing electrode are formed above the end of the conductive layer, wherein the first sensing electrode and the second sensing electrode are respectively disposed in contact with the end of the conductive layer and partially fill the opening.

[0033] A sensitive material layer is formed above the conductive layer, wherein the sensitive material layer is in contact with at least a portion of the conductive layer and fills a portion of the opening;

[0034] A back hole is formed on the lower surface layer of the substrate.

[0035] The above-described method for fabricating a gas sensor involves forming a conductive layer on the upper surface of the substrate; the conductive layer includes a first comb structure and a second comb structure, wherein the comb portions of the first comb structure and the comb portions of the second comb structure are arranged alternately; a first insulating layer is formed on the upper surface of the conductive layer, the sidewalls of the conductive layer, and the upper surface of the substrate; a sidewall structure is formed on the sidewalls of the first insulating layer, wherein the sidewalls of the first insulating layer correspond to the sidewalls of the conductive layer; a first oxide layer is formed on the surface of the upper surface of the first insulating layer and the sidewall structure; a portion of the first oxide layer is removed to form an initial opening, and a portion of the first oxide layer covering the end of the sidewall structure is removed; wherein the initial opening exposes the first insulating layer. The upper surface layer of the conductive layer is formed by removing a portion of the first insulating layer based on the initial opening to form an opening, wherein the opening exposes the upper surface layer of the conductive layer; a first heating electrode and a second heating electrode are formed on the upper surface layer of the first insulating layer, wherein the first heating electrode and the second heating electrode are respectively in contact with the ends of the sidewall structure; a first sensing electrode and a second sensing electrode are formed above the ends of the conductive layer, wherein the first sensing electrode and the second sensing electrode are respectively in contact with the ends of the conductive layer and partially fill the opening; a sensitive material layer is formed above the conductive layer, wherein the sensitive material layer is in contact with at least a portion of the conductive layer and partially fills the opening; and a back hole is formed on the lower surface layer of the substrate. Since the sidewall structure, which serves as the heating layer of the heating component, is designed on the sidewall of the conductive layer, device design area can be saved.

[0036] In one embodiment, a sidewall structure is formed on the sidewall of the first insulating layer, including:

[0037] An initial sidewall structure is formed on the surface of the first insulating layer;

[0038] A self-aligned sidewall process is used to remove a portion of the initial sidewall structure to form the sidewall structure; the sidewall structure includes the portion of the initial sidewall structure remaining on the sidewall of the first insulating layer after the portion of the initial sidewall structure has been removed.

[0039] In one embodiment, forming a conductive layer on the upper surface of the substrate includes:

[0040] A first comb tooth structure and a second comb tooth structure are formed on the upper surface layer of the substrate. The first comb tooth structure and the second comb tooth structure together constitute the conductive layer. The comb tooth portions of the first comb tooth structure and the comb tooth portions of the second comb tooth structure are arranged alternately. The first comb tooth structure also includes a first comb tooth electrode, which is connected to a first end of the comb tooth portion of the first comb tooth structure. The second comb tooth structure also includes a second comb tooth electrode, which is connected to a first end of the comb tooth portion of the second comb tooth structure.

[0041] In one embodiment, removing the first oxide layer partially covering the end of the sidewall structure includes:

[0042] Remove the first oxide layer from the surfaces of the first sidewall, the second sidewall, the third sidewall, and the fourth sidewall; wherein the first sidewall is the sidewall structure at the first end of the conductive layer, the second sidewall is the sidewall structure at the second end of the conductive layer, the third sidewall is the sidewall structure at the second end of the comb tooth portion of the first comb tooth structure, and the fourth sidewall is the sidewall structure at the first end of the comb tooth portion of the second comb tooth structure.

[0043] In one embodiment, forming a first heating electrode and a second heating electrode on the upper surface of the first insulating layer includes:

[0044] A first heating electrode and a second heating electrode are formed on the upper surface of the first insulating layer, and a first sensing electrode is formed above the first comb electrode, and a second sensing electrode is formed above the second comb electrode; the first sensing electrode fills the opening corresponding to the top of the first comb electrode, and the second sensing electrode fills the opening corresponding to the top of the second comb electrode; wherein, the first heating electrode is in contact with the first sidewall and the second sidewall respectively, and the second heating electrode is in contact with the third sidewall and the fourth sidewall respectively.

[0045] In one embodiment, the first heating electrode includes a first sub-electrode and a second sub-electrode, and the second heating electrode includes a third sub-electrode and a fourth sub-electrode. The formation of the first heating electrode and the second heating electrode on the upper surface of the first insulating layer includes:

[0046] A first sub-electrode, a second sub-electrode, a third sub-electrode, and a fourth sub-electrode are formed on the upper surface of the first insulating layer, wherein the first sub-electrode is in contact with the first sidewall; the second sub-electrode is in contact with the second sidewall; the third sub-electrode is in contact with the third sidewall; and the fourth sub-electrode is in contact with the fourth sidewall.

[0047] In one embodiment, before forming a conductive layer on the upper surface of the substrate, the method for fabricating the gas sensor further includes:

[0048] A second insulating layer is formed on the upper surface of the substrate, and a third insulating layer is formed on the lower surface of the substrate;

[0049] A second oxide layer is formed on the upper surface of the second insulating layer, and a third oxide layer is formed on the lower surface of the third insulating layer, wherein the conductive layer is located on the upper surface of the second oxide layer; wherein the back hole penetrates a portion of the third oxide layer, a portion of the third insulating layer, and a portion of the substrate to expose a portion of the lower surface of the second insulating layer. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 This is a flowchart of a method for preparing a heating component provided in one embodiment;

[0052] Figure 2 This is a top view of the structure obtained in step S102 of the method for preparing the heating component provided in one embodiment;

[0053] Figure 3 This is a top view of the structure obtained in step S102 of the method for preparing the heating component provided in another embodiment;

[0054] Figure 4 for Figure 3 A schematic diagram of the cross-sectional structure along the A-A' direction;

[0055] Figure 5 for Figure 3 A schematic diagram of the cross-sectional structure along the B-B' direction;

[0056] Figure 6 This is a schematic cross-sectional view of the structure obtained in step S103 of the method for preparing the heating component provided in one embodiment;

[0057] Figure 7 This is a top view of the structure obtained in step S104 of the method for preparing the heating component provided in one embodiment.

[0058] Figure 8 for Figure 7 A schematic diagram of the cross-sectional structure along the C-C' direction;

[0059] Figure 9 for Figure 7 A schematic diagram of the cross-sectional structure along the D-D' direction;

[0060] Figure 10 This is a top view of the structure obtained in step S105 of the method for preparing the heating component provided in one embodiment.

[0061] Figure 11 This is a flowchart of step S104 in the method for preparing a heating component provided in one embodiment;

[0062] Figure 12 This is a schematic cross-sectional view of the structure obtained in step S1041 of the method for preparing the heating component provided in one embodiment;

[0063] Figure 13 This is a schematic cross-sectional view of the structure obtained in step S1041 of the method for preparing the heating component provided in another embodiment;

[0064] Figure 14 This is a top view of the first comb tooth structure and the second comb tooth structure in a heating assembly provided in one embodiment;

[0065] Figure 15 This is a top view of the structure obtained in step S105 of the method for preparing the heating component provided in another embodiment.

[0066] Figure 16 for Figure 15 A schematic diagram of the cross-sectional structure along the F-F' direction;

[0067] Figure 17 This is a top view of the heating assembly provided in another embodiment;

[0068] Figure 18 This is a top view of the heating assembly provided in another embodiment;

[0069] Figure 19 This is a flowchart of a method for fabricating a gas sensor provided in one embodiment;

[0070] Figure 20 This is a schematic cross-sectional view of the structure obtained in step S205 of the gas sensor fabrication method provided in one embodiment;

[0071] Figure 21 This is a schematic cross-sectional view of the structure obtained in step S207 of the gas sensor fabrication method provided in one embodiment;

[0072] Figure 22 for Figure 21 A schematic diagram of the cross-sectional structure along the G-G' direction;

[0073] Figure 23 for Figure 21 A schematic diagram of the cross-sectional structure along the H-H' direction;

[0074] Figure 24 This is a schematic cross-sectional view of the structure obtained in step S209 of the gas sensor fabrication method provided in one embodiment;

[0075] Figure 25 for Figure 24 A schematic diagram of the cross-sectional structure along the I-I' direction;

[0076] Figure 26 This is a schematic cross-sectional view of the structure obtained in step S210 of the gas sensor fabrication method provided in one embodiment;

[0077] Figure 27 for Figure 26 A schematic diagram of the cross-sectional structure along the J-J' direction;

[0078] Figure 28 This is a schematic cross-sectional view of the structure obtained in step S211 of the gas sensor fabrication method provided in one embodiment;

[0079] Figure 29 This is a flowchart illustrating the steps of forming a second oxide layer, a second insulating layer, a third oxide layer, and a third insulating layer in a method for fabricating a gas sensor provided in one embodiment.

[0080] Figure 30 This is a schematic cross-sectional view of the structure obtained in step S2902 of the gas sensor fabrication method provided in one embodiment;

[0081] Figure 31 A flowchart illustrating a method for preparing a heating component according to another embodiment;

[0082] Figure 32 This is a top view of the structure obtained in step S17 of the method for preparing the heating component provided in one embodiment.

[0083] Figure 33 A flowchart illustrating a method for fabricating a gas sensor as provided in another embodiment;

[0084] Figure 34 This is a top view of the structure obtained in step S33 of the method for preparing a heating component provided in one embodiment.

[0085] Explanation of reference numerals in the attached drawings: 1-Substrate, 11-Second insulating layer, 12-Third insulating layer, 13-Second oxide layer, 14-Third oxide layer, 15-Back hole, 2-Conductive layer, 21-First comb tooth structure, 211-First main comb tooth, 2111-Main body of the first main comb tooth, 2112-Connecting part of the first main comb tooth, 212-First branch comb tooth, 213-Second branch comb tooth, 214-First comb tooth electrode, 22-Second comb tooth structure, 221-Second main comb tooth, 2211-Main body of the second main comb tooth, 2212-Second main comb tooth electrode. Connecting part, 222-third branch comb tooth, 223-fourth branch comb tooth, 224-second comb tooth electrode, 23-sensitive material layer, 3-first insulating layer, 4-sidewall structure, 41-first sidewall, 42-second sidewall, 43-third sidewall, 44-fourth sidewall, 401-initial sidewall structure, 5-first heating electrode, 51-first sub-electrode, 52-second sub-electrode, 6-second heating electrode, 61-third sub-electrode, 62-fourth sub-electrode, 7-first oxide layer, 71-opening, 8-first sensing electrode, 9-second sensing electrode. Detailed Implementation

[0086] 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.

[0087] 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.

[0088] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, parts, regions, layers, doping types, and / or portions, these elements, parts, regions, layers, doping types, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, part, region, layer, doping type, or portion from another element, part, region, layer, doping type, or portion. Therefore, without departing from the teachings of this invention, the first element, component, region, layer, doping type or portion discussed below may be represented as the second element, component, region, layer or portion; for example, the first doping type may be P-type and the second doping type may be N-type, or the first doping type may be N-type and the second doping type may be P-type.

[0089] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as “below,” “under,” or “below” will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.

[0090] When used herein, the singular forms of “a,” “an,” and “ / the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, in this specification, the term “and / or” includes any and all combinations of the associated listed items.

[0091] Please see Figure 1 The present invention provides a method for preparing a heating component, comprising the following steps:

[0092] S101: Provides the substrate.

[0093] like Figure 2 As shown, the material of the substrate 1 can be any suitable material known in the art, such as at least one of the following: silicon (Si), germanium (Ge), red phosphorus, silicon germanium (SiGe), silicon carbide (SiC), silicon germanium carbon (SiGeC), indium arsenide (InAs), gallium arsenide (GaAs), indium phosphide (InP), or other III / V compound semiconductors, including multilayer structures composed of these semiconductors, or silicon on insulator (SOI), silicon on insulator (SSOI), silicon on insulator (S-SiGeOI), silicon on insulator (SiGeOI), and germanium on insulator (GeOI), or it can be a double-side polished wafer (DSP), or a ceramic substrate 1 such as alumina, a quartz or glass substrate 1, etc., which are not limited in this embodiment.

[0094] S102: A conductive layer is formed on the upper surface of the substrate.

[0095] Here, conductive layer 2 refers to the main sensing component in the sensing assembly used to realize the sensing function. The shape of conductive layer 2 can be determined according to the design shape of the specific sensing assembly, for example, Figure 2 As shown, the shape of conductive layer 2 can also be rectangular, or, as shown in the figure, Figure 5 As shown, the shape of the conductive layer 2 can be an interlaced comb shape. For example, the shape of the conductive layer 2 can also be a square, a circle, or other suitable shapes. This embodiment does not impose any limitations on this.

[0096] Taking the shape of conductive layer 2 as an example, which is an interlaced comb shape, such as Figure 3 , Figure 4 as well as Figure 5 As shown, Figure 3 This can be viewed as a top view of the heating assembly when the conductive layer 2 is comb-shaped. Figure 4 It can be regarded as Figure 3 A schematic diagram of the cross-sectional structure along the A-A' direction. Figure 5 It can be regarded as Figure 3 The diagram shows a cross-sectional view of the structure along the B-B' direction. The material of the conductive layer 2 may include polycrystalline silicon or metal; this embodiment is not limited thereto. Furthermore, the polycrystalline silicon may be P-type or N-type; this embodiment is not limited thereto.

[0097] S103: A first insulating layer is formed on the upper surface of the conductive layer, the sidewall of the conductive layer, and the upper surface of the substrate.

[0098] Taking the shape of conductive layer 2 as an example of interlaced comb teeth, please combine... Figure 3 , Figure 4 And see Figure 6 To facilitate understanding of this solution, Figure 6 It can be regarded as in Figure 3 The schematic diagram shows the cross-sectional structure of the structure obtained after covering the surface of the structure with a first insulating layer 3. It can be understood that for Figure 2 The entire structure is covered by a first insulating layer 3. The first insulating layer 3 may include a silicon nitride layer.

[0099] S104: A sidewall structure is formed on the sidewall of the first insulating layer, wherein the sidewall of the first insulating layer corresponds to the sidewall of the conductive layer.

[0100] Taking the conductive layer 2 as an example, which has an interlaced comb-like shape, for instance... Figure 7 , Figure 8 as well as Figure 9 As shown, Figure 8 It can be regarded as Figure 7 A schematic diagram of the cross-sectional structure along the C-C' direction. Figure 9 It can be regarded as Figure 7 The diagram shows a cross-sectional view of the structure along the D-D' direction. The sidewall structure 4 may include polysilicon or metal; this embodiment is not limited in this regard. Furthermore, the polysilicon may be P-type or N-type in terms of conductivity; this embodiment is not limited in this regard either.

[0101] The sidewall structure 4 can serve as a heating layer in the heating assembly. The material of the sidewall structure 4 can include polycrystalline silicon or metal; this embodiment is not limited thereto. Furthermore, the polycrystalline silicon can be P-type or N-type conductive; this embodiment is not limited thereto. Since the sidewall structure 4 is located on the sidewall of the conductive layer 2, it does not occupy excessive device design area. Simultaneously, because the sidewall structure 4 is separated from the conductive layer 2 by the first insulating layer 3, the conductive layer 2 and the sidewall structure 4 can operate independently of each other.

[0102] S105: A first heating electrode and a second heating electrode are formed on the upper surface of the first insulating layer; wherein the first heating electrode and the second heating electrode are respectively in contact with the ends of the sidewall structure.

[0103] Taking the conductive layer 2 as an example, which has an interlaced comb-like shape, for instance... Figure 10As shown, the materials of the first heating electrode 5 and the second heating electrode 6 can be any suitable metal electrode material in the art, such as aluminum. Since the first heating electrode 5 and the second heating electrode 6 can be connected by the sidewall structure 4, a complete heating assembly can be formed by the first heating electrode 5, the second heating electrode 6, and the sidewall structure 4, thereby realizing the heating function.

[0104] The above-described method for fabricating a heating component involves forming a conductive layer on the upper surface of a substrate; forming a first insulating layer on the upper surface of the conductive layer, the sidewalls of the conductive layer, and the upper surface of the substrate; forming a sidewall structure on the sidewalls of the first insulating layer, wherein the sidewalls of the first insulating layer correspond to the sidewalls of the conductive layer; and forming a first heating electrode and a second heating electrode on the upper surface of the first insulating layer. The first heating electrode and the second heating electrode are respectively positioned in contact with the ends of the sidewall structure. Because the sidewall structure, which serves as the heating layer of the heating component, is designed on the sidewalls of the conductive layer, it saves on device design area.

[0105] In one embodiment, such as Figure 11 As shown, step S104 above includes:

[0106] S1041: An initial sidewall structure 401 is formed on the surface of the first insulating layer 3, such as Figure 12 as well as Figure 13 As shown. Depending on the sidewall material, a suitable deposition process can be used to form the initial sidewall structure 401, such as atomic layer deposition (ALD), physical vapor deposition (PVD), or chemical vapor deposition (CVD), etc., without limitation.

[0107] S1042: A portion of the initial sidewall structure 401 is removed using a self-aligned sidewall process to form a sidewall structure 4; the sidewall structure 4 includes the portion of the initial sidewall structure 401 remaining on the sidewall of the first insulating layer 3 after the removal of the portion of the initial sidewall structure 401, such as... Figure 8 as well as Figure 9 As shown.

[0108] Please combine Figure 8 , Figure 9 And see Figure 12 as well as Figure 13 , Figure 12 It can be regarded as the formation Figure 8 A cross-sectional schematic diagram of the structure obtained after the initial sidewall structure 401 is formed on the surface of the first insulating layer 3 before the structure in the middle; Figure 13 It can be regarded as the formation Figure 9This is a cross-sectional view of the structure obtained after forming the initial sidewall structure 401 on the surface of the first insulating layer 3 before the structure in the diagram. During the self-aligned sidewall process, no photolithography step is required; the initial sidewall structure 401 can be directly etched away, removing a portion of it entirely. The portion of the initial sidewall structure 401 located on the sidewall of the first insulating layer 3 will be retained as the sidewall structure 4. Therefore, in this embodiment, the photolithography step can be omitted, and the initial sidewall structure 401 can be directly etched to form the sidewall structure 4 on the sidewall of the first insulating layer 3, thereby saving costs.

[0109] Furthermore, by controlling the etching time of the self-aligned sidewall process, the size and dimensions of the sidewall structure 4 can be controlled, thereby controlling the heating resistance of the sidewall structure 4 as a heating component. For example, see... Figure 9 In the diagram, the cross-sectional view of sidewall structure 4 resembles a quarter circle. It can be understood that a longer etching time results in a smaller diameter quarter circle, while a shorter etching time results in a larger diameter quarter circle. In other words, by controlling the etching time of the self-aligned sidewall process, the dimensions of sidewall structure 4 can be controlled, allowing for flexible adjustment of the heating resistor in the heating assembly according to actual application requirements.

[0110] In one embodiment, such as Figure 14 As shown, step S102 includes: forming a first comb structure 21 and a second comb structure 22 on the upper surface of the substrate 2. The first comb structure 21 and the second comb structure 22 together constitute a conductive layer 2. The comb teeth of the first comb structure 21 and the comb teeth of the second comb structure 22 are arranged alternately. The first comb structure 21 also includes a first comb electrode 214, which is connected to the first end of the comb teeth of the first comb structure 21. The second comb structure 22 also includes a second comb electrode 224, which is connected to the first end of the comb teeth of the second comb structure 22.

[0111] Optional, such as Figure 15 as well as Figure 16 As shown, in one embodiment, the sidewall structure 4 at the intersection of the comb tooth portion of the first comb tooth structure 21 and the comb tooth portion of the second comb tooth structure 22 overlaps.

[0112] in, Figure 16 It can be regarded as Figure 15 A schematic diagram of the cross-sectional structure along the F-F' direction is shown. Through appropriate layout design, the distance between the comb teeth of the first comb tooth structure 21 and the comb teeth of the second comb tooth structure 22 is minimized. At this point, as shown... Figure 12As shown, the sidewall structure 4 will fill the gap between the comb teeth of the first comb tooth structure 21 and the comb teeth of the second comb tooth structure 22, thereby further reducing the layout design area.

[0113] Optionally, based on the above embodiments, in one embodiment, such as Figure 14 As shown, the comb tooth portion of the first comb tooth structure 21 includes a first main comb tooth 211, a first branch comb tooth 212, and a plurality of spaced-apart second branch comb teeth 213. Each second branch comb tooth 213 is connected to the first main comb tooth 211. The first end of the first main comb tooth 211 serves as the first end of the comb tooth portion of the first comb tooth structure 21. The first branch comb teeth 212 are connected to the second branch comb teeth 213 near the second end of the first main comb tooth 211. The free end of the first branch comb tooth 212 serves as the second end of the comb tooth portion of the first comb tooth structure 21. The second comb tooth structure 22 includes a second main comb tooth 221, a third branch comb tooth 222, and a plurality of spaced fourth branch comb teeth 223. Each fourth branch comb tooth 223 is connected to the third main comb tooth. The first end of the second main comb tooth 221 serves as the first end of the comb tooth portion of the second comb tooth structure 22. The third branch comb tooth 222 is connected to the fourth branch comb tooth 223 near the second end of the second main comb tooth 221. The free end of the third branch comb tooth 222 serves as the second end of the comb tooth portion of the second comb tooth structure 22.

[0114] Based on the above embodiments, in one embodiment, please continue to refer to... Figure 14 The first comb structure 21 further includes a first comb electrode 214, which is connected to the first end of the comb portion of the first comb structure 21. The second comb structure 22 further includes a second comb electrode 224, which is connected to the first end of the comb portion of the second comb structure 22.

[0115] Based on the above embodiments, in one embodiment, please continue to refer to... Figure 14 The first main comb tooth 211 and the first branch comb tooth 212 both extend along the first direction, and each second branch comb tooth 213 extends along the second direction, wherein the first direction and the second direction intersect; the second main comb tooth 221 and the third branch comb tooth 222 both extend along the first direction, and each fourth branch comb tooth 223 extends along the second direction.

[0116] The first direction can be, for example: Figure 14 The first direction is shown as a horizontal direction. Of course, in other manufacturing processes and application environments, the first direction can be other suitable directions, and this embodiment is not limited thereto; the second direction can be perpendicular to the first direction, and the second direction can be as shown in the figure. Figure 14The vertical direction is shown in the figure. Of course, in other manufacturing processes and application environments, the second direction can be other suitable directions, and this embodiment is not limited to them.

[0117] Optionally, based on the above embodiments, in one embodiment, please continue to refer to... Figure 14 The first end of the first main comb tooth 211 is aligned with the free end of the third branch comb tooth 222; the first end of the second main comb tooth 221 is aligned with the free end of the first branch comb tooth 212. This alignment arrangement further reduces the device design area.

[0118] Optionally, based on the above embodiments, in one embodiment, such as Figure 14 As shown, step S105 includes: forming a first heating electrode 5 and a second heating electrode 6 on the upper surface of the first insulating layer 3, wherein the first heating electrode 5 is respectively in contact with a first sidewall 41 located on the sidewall of the first comb structure 21 and a second sidewall 42 located on the sidewall of the second comb structure 22, wherein the first sidewall 41 is the sidewall structure 4 at the first end of the comb tooth portion of the first comb structure 21, and the second sidewall 42 is the sidewall structure 4 at the second end of the comb tooth portion of the second comb structure 22; the second heating electrode 6 is respectively in contact with a third sidewall 43 located on the sidewall of the first comb structure 21 and a fourth sidewall 44 located on the sidewall of the second comb structure 22, wherein the third sidewall 43 is the sidewall structure 4 at the second end of the comb tooth portion of the first comb structure 21, and the fourth sidewall 44 is the sidewall structure 4 at the first end of the comb tooth portion of the second comb structure 22.

[0119] To facilitate understanding of this solution, Figure 14 In the first comb structure 21, the first end of the comb tooth portion is a portion of the comb tooth structure located at the right end of the first comb structure 21, and the second end of the comb tooth portion of the first comb structure 21 is a portion of the comb tooth structure located at the left end of the first comb structure 21; similarly, the first end of the comb tooth portion of the second comb structure 22 is a portion of the comb tooth structure located at the left end of the second comb structure 22, and the second end of the comb tooth portion of the second comb structure 22 is a portion of the comb tooth structure located at the right end of the second comb structure 22. At this time, by... Figure 14 It can be seen that since the first heating electrode 5 is in contact with the first side wall 41 and the second side wall 42, and the second heating electrode 6 is in contact with the third side wall 43 and the fourth side wall 44, the first heating electrode 5 and the second heating electrode 6 can be connected through the side wall structure 4, thus forming a complete heating assembly.

[0120] Based on the above embodiments, in one embodiment, such as Figure 17As shown, the first heating electrode 5 includes a first sub-electrode 51 and a second sub-electrode 52, and the second heating electrode 6 includes a second sub-electrode 53 and a fourth sub-electrode 54. The above step S105 includes: forming the first sub-electrode 51, the second sub-electrode 52, the second sub-electrode 53 and the fourth sub-electrode 54 on the upper surface of the first insulating layer, wherein the first sub-electrode 51 is in contact with the first sidewall 41, the second sub-electrode 52 is in contact with the second sidewall 42, the third sub-electrode 53 is in contact with the third sidewall 43, and the fourth sub-electrode 54 is in contact with the fourth sidewall 44.

[0121] Optionally, based on the above embodiments, in one embodiment, such as Figure 18 As shown, the main body portion 2111 of the first main comb tooth and the first branch comb tooth 212 both extend along the first direction, and the connecting portion 2112 of the first main comb tooth and each of the second branch comb teeth 213 both extend along the second direction, wherein the first direction and the second direction intersect; the main body portion 2211 of the second main comb tooth and the third branch comb tooth 222 both extend along the first direction, and the connecting portion 2212 of the second main comb tooth and each of the fourth branch comb teeth 223 both extend along the second direction.

[0122] Optionally, before performing step S102 above, the method for preparing the heating component may further include:

[0123] S2801: A second insulating layer 11 is formed on the upper surface of the substrate 1, and a third insulating layer 12 is formed on the lower surface of the substrate 1, such as... Figure 30 As shown. The material of the second insulating layer 11 and the material of the third insulating layer 12 can be the same, for example, both can be silicon nitride.

[0124] S2802: A second oxide layer 13 is formed on the upper surface of the second insulating layer 11, and a third oxide layer 14 is formed on the lower surface of the third insulating layer 12. The conductive layer 2 is located on the upper surface of the second oxide layer 13. Figure 30 As shown. The material of the second oxide layer 13 and the third oxide layer 14 can be the same, for example, both can be silicon oxide. Additionally, as... Figure 30 As shown, the back hole 15 penetrates a portion of the third oxide layer 14, a portion of the third insulating layer 12, and a portion of the substrate 1 to expose a portion of the lower surface layer of the second insulating layer 11.

[0125] The second insulating layer 11 and the second oxide layer 13 serve to insulate the conductive layer 2 from the substrate 1. The third insulating layer 12 and the third oxide layer 14 can be used as a hard mask to etch and form back vias.

[0126] To facilitate understanding by those skilled in the art, the preparation method of the heating component provided in this application is described in detail below. Please refer to [link / reference needed]. Figure 31The method for preparing the above-mentioned heating component may include:

[0127] S10: Provides a substrate;

[0128] S11: A second insulating layer is formed on the upper surface of the substrate, and a third insulating layer is formed on the lower surface of the substrate;

[0129] S12: A second oxide layer is formed on the upper surface of the second insulating layer, and a third oxide layer is formed on the lower surface of the third insulating layer. The conductive layer is located on the upper surface of the second oxide layer.

[0130] S13: A conductive layer is formed on the upper surface of the substrate;

[0131] S14: A first insulating layer is formed on the upper surface of the conductive layer, the sidewall of the conductive layer, and the upper surface of the substrate;

[0132] S15: An initial sidewall structure is formed on the surface of the first insulating layer;

[0133] S16: A portion of the initial sidewall structure is removed using a self-aligned sidewall process to form a sidewall structure; the sidewall structure includes a portion of the initial sidewall structure remaining on the sidewall of the first insulating layer after the portion of the initial sidewall structure has been removed; wherein the sidewall of the first insulating layer corresponds to the sidewall of the conductive layer.

[0134] S17: A first heating electrode and a second heating electrode are formed on the upper surface of the first insulating layer; wherein the first heating electrode and the second heating electrode are respectively in contact with the ends of the sidewall structure.

[0135] The cross-sectional structural diagram of the heating component obtained after step S17 can be referenced. Figure 32 It should be noted that the descriptions in S10-S17 above can be found in the relevant descriptions in the above embodiments, and their effects are similar. Therefore, they will not be repeated here.

[0136] It should be understood that although the steps in the flowcharts of the above embodiments are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0137] Please see Figure 19This application also provides a method for preparing a gas sensor, comprising the following steps:

[0138] S201: Provides a substrate.

[0139] S202: A conductive layer is formed on the upper surface of the substrate.

[0140] S203: A first insulating layer is formed on the upper surface of the conductive layer, the sidewall of the conductive layer, and the upper surface of the substrate.

[0141] S204: A sidewall structure is formed on the sidewall of the first insulating layer, wherein the sidewall of the first insulating layer corresponds to the sidewall of the conductive layer.

[0142] The above-described method for preparing a gas sensor can be considered as a further improvement upon the above-described method for preparing a heating component. Therefore, the implementation principle and beneficial effects of steps S201 to S204 in the above-described method for preparing a gas sensor are similar to those of steps S101 to S104 in the above-described method for preparing a heating component, and will not be repeated here.

[0143] S205: A first oxide layer is formed on the upper surface of the first insulating layer and on the surface of the sidewall structure.

[0144] like Figure 20 As shown, the first oxide layer 7 may include a silicon oxide layer. The first oxide layer 7 serves to protect the sidewall structure 4.

[0145] S206: Remove a portion of the first oxide layer to form an initial opening, and remove a portion of the first oxide layer covering the end of the sidewall structure; wherein the initial opening exposes the upper surface of the first insulating layer.

[0146] S207: The first insulating layer is removed based on the initial opening to form an opening, wherein the opening exposes the upper surface of the conductive layer.

[0147] Taking the conductive layer 2 as an example, which has an interlaced comb-like shape, for instance... Figure 21 , Figure 22 as well as Figure 23 As shown, to facilitate a better understanding of this solution, Figure 21 The white part in the middle is the location of opening 71, but it should be understood that... Figure 21 The opening 71 in the middle actually needs to expose the upper surface of the conductive layer 2. Figure 22 It can be regarded as Figure 21 A schematic diagram of the cross-sectional structure along the G-G' direction. Figure 23 It can be regarded as Figure 21 A schematic diagram of the cross-sectional structure along the H-H' direction. (From...) Figure 21 , Figure 22 as well as Figure 23It can be seen that by removing part of the first oxide layer 7 covering the end of the sidewall structure 4, contact points can be provided for the first heating electrode 5 and the second heating electrode 6 to contact with the sidewall structure 4, so that the first heating electrode 5, the second heating electrode 6 and the sidewall structure 4 can form a complete heating assembly.

[0148] S208: A first heating electrode and a second heating electrode are formed on the upper surface of the first insulating layer, wherein the first heating electrode and the second heating electrode are respectively in contact with the ends of the sidewall structure.

[0149] Taking the conductive layer 2 as an example, which has an interlaced comb-like shape, for instance... Figure 24 as well as Figure 25 As shown, Figure 25 It can be regarded as Figure 24 The diagram shows a cross-sectional view of the structure along the I-I' direction. The materials for both the first heating electrode 5 and the second heating electrode 6 can be metallic electrode materials, such as copper, gold, titanium, silver, aluminum, etc., or multilayer metals composed of the aforementioned materials, or metal alloys, etc. This embodiment does not impose any limitations. By designing a suitable photolithography pattern and performing metal deposition, photolithography, and other process steps, the first heating electrode 5 and the second heating electrode 6 can be formed simultaneously.

[0150] S209: A first sensing electrode and a second sensing electrode are formed above the end of the conductive layer, wherein the first sensing electrode and the second sensing electrode are respectively in contact with the end of the conductive layer and partially fill the opening.

[0151] Taking the shape of conductive layer 2 as an example of interlaced comb teeth, please refer to the following: Figure 24 as well as Figure 25 The materials of the first sensing electrode 8 and the second sensing electrode 9 can both be metal electrode materials, such as copper, gold, titanium, silver, aluminum, etc., or multilayer metals composed of the above-mentioned metals, or metal alloys, etc. This embodiment does not impose any limitations. By designing a suitable photolithography pattern and performing metal deposition, photolithography, and other process steps, the first sensing electrode 8 and the second sensing electrode 9 can be formed simultaneously.

[0152] Additionally, it should be noted that in the actual fabrication process, depending on the specific shape of the conductive layer and the specific fabrication process of the gas sensor, it can be determined whether the first heating electrode 5, the second heating electrode 6, the first sensing electrode 8, and the second sensing electrode 9 are fabricated simultaneously. For example, still taking the conductive layer 2 as having an interlaced comb-like shape as an example, see [reference needed]. Figure 24Since the first heating electrode 5, the second heating electrode 6, the first sensing electrode 8, and the second sensing electrode 9 are located on the same layer, the photolithography pattern can be appropriately modified in the same step to simultaneously fabricate the first heating electrode 5, the second heating electrode 6, the first sensing electrode 8, and the second sensing electrode 9. Of course, it is understandable that the first heating electrode 5, the second heating electrode 6, the first sensing electrode 8, and the second sensing electrode 9 can also be fabricated without using the same step.

[0153] Furthermore, when designing the shape of the conductive layer 2, in order to facilitate the connection between the conductive layer 2 and the first sensing electrode 8 and the second sensing electrode 9 to form a sensing assembly, the area of ​​the end portion of the conductive layer 2 can usually be designed to be larger. For example, still taking the shape of the conductive layer 2 as an interlaced comb shape as an example, please refer to... Figure 21 as well as Figure 24 ,exist Figure 21 In this process, by appropriately designing the layout, the end of the conductive layer 2 is made larger. This allows the first sensing electrode 8 and the second sensing electrode 9 to fill part of the opening 71 and more easily contact the larger end of the conductive layer 2 during the formation of the first sensing electrode 8 and the second sensing electrode 9 in step S209. Of course, depending on the specific fabrication process, it is also possible to design the end of the conductive layer 2 to be smaller, as long as the first sensing electrode 8 and the second sensing electrode 9 maintain contact with the conductive layer 2.

[0154] S210: A sensitive material layer is formed above the conductive layer, wherein the sensitive material layer is in contact with at least a portion of the conductive layer and fills a portion of the opening.

[0155] Taking the conductive layer 2 as an example, which has an interlaced comb-like shape, for instance... Figure 26 as well as Figure 27 As shown, Figure 27 for Figure 26 The diagram shows the cross-sectional structure along the J-J' direction. This is for ease of understanding of the scheme. Figure 26 The circular dashed box in the figure indicates the coating area of ​​the sensitive material layer 23. Of course, the coating area and shape of the sensitive material layer 23 are not limited to this area. Figure 26 The scheme shown can be adapted to specific manufacturing processes in practical applications, with parameters such as the coating range and shape of the sensitive material layer 23 determined based on the manufacturing process. The goal is simply to connect the conductive layers 2 using the sensitive material layer 23; this embodiment does not impose any limitations on this. The coated sensitive material layer 23 reacts to a specific gas, resulting in a change in resistance. This change in resistance is monitored by the first sensing electrode 8 and the second sensing electrode 9, ultimately achieving the sensing function of a gas sensor.

[0156] The sensitive material layer 23 can be made of tin oxide or titanium oxide, or other suitable sensitive materials. Different sensitive materials can be applied to achieve the corresponding sensing functions depending on the application scenario. The process of applying the sensitive material layer 23 can include dispensing, inkjet printing, or printing.

[0157] S211: A back hole is formed on the lower surface layer of the substrate.

[0158] Taking the conductive layer 2 as an example, which has an interlaced comb-like shape, for instance... Figure 28 As shown, the back via 15 can accelerate the heat dissipation of the heating components of the gas sensor. The process for forming the back via 15 can include through-silicon via etching or wet etching.

[0159] The above-described method for fabricating a gas sensor involves forming a conductive layer on the upper surface of a substrate; the conductive layer includes a first comb structure and a second comb structure, wherein the comb teeth of the first comb structure and the comb teeth of the second comb structure are arranged alternately; forming a first insulating layer on the upper surface of the conductive layer, the sidewalls of the conductive layer, and the upper surface of the substrate; forming a sidewall structure on the sidewalls of the first insulating layer, wherein the sidewalls of the first insulating layer correspond to the sidewalls of the conductive layer; forming a first oxide layer on the surface of the upper surface of the first insulating layer and the sidewall structure; removing a portion of the first oxide layer to form an initial opening, and removing a portion of the first oxide layer covering the ends of the sidewall structure; wherein the initial opening exposes the upper surface of the first insulating layer. The surface layer includes: a first insulating layer partially removed from the initial opening to form an opening, wherein the opening exposes the upper surface layer of the conductive layer; a first heating electrode and a second heating electrode are formed on the upper surface layer of the first insulating layer, wherein the first heating electrode and the second heating electrode are respectively in contact with the ends of the sidewall structure; a first sensing electrode and a second sensing electrode are formed above the ends of the conductive layer, wherein the first sensing electrode and the second sensing electrode are respectively in contact with the ends of the conductive layer and partially fill the opening; a sensitive material layer is formed above the conductive layer, wherein the sensitive material layer is in contact with at least a portion of the conductive layer and partially fills the opening; and a back hole is formed on the lower surface layer of the substrate. Because the sidewall structure of the heating layer, which serves as the heating component, is designed on the sidewall of the conductive layer, device design area can be saved.

[0160] In one embodiment, step S204 above includes:

[0161] S2041: An initial sidewall structure 401 is formed on the surface of the first insulating layer 3, such as Figure 14 as well as Figure 15As shown. Depending on the sidewall material, a suitable deposition process can be used to form the initial sidewall structure 401, such as atomic layer deposition (ALD), physical vapor deposition (PVD), or chemical vapor deposition (CVD), etc., without limitation.

[0162] S2042: A portion of the initial sidewall structure 401 is removed using a self-aligned sidewall process to form a sidewall structure 4; the sidewall structure 4 includes the portion of the initial sidewall structure 401 remaining on the sidewall of the first insulating layer 3 after the removal of the initial sidewall structure 401, such as... Figure 8 as well as Figure 9 As shown.

[0163] Please combine Figure 8 , Figure 9 And see Figure 12 as well as Figure 13 , Figure 12 It can be regarded as the formation Figure 8 A cross-sectional schematic diagram of the structure obtained after the initial sidewall structure 401 is formed on the surface of the first insulating layer 3 before the structure in the middle; Figure 13 It can be regarded as the formation Figure 9 This is a cross-sectional view of the structure obtained after forming the initial sidewall structure 401 on the surface of the first insulating layer 3 before the structure in the diagram. During the self-aligned sidewall process, no photolithography step is required; the initial sidewall structure 401 can be directly etched away, removing a portion of it entirely. The portion of the initial sidewall structure 401 located on the sidewall of the first insulating layer 3 will be retained as the sidewall structure 4. Therefore, in this embodiment, the photolithography step can be omitted, and the initial sidewall structure 401 can be directly etched to form the sidewall structure 4 on the sidewall of the first insulating layer 3, thereby saving costs.

[0164] Furthermore, by controlling the etching time of the self-aligned sidewall process, the size and dimensions of the sidewall structure 4 can be controlled, thereby controlling the heating resistance of the sidewall structure 4 as a heating component. For example, see... Figure 9 In the diagram, the cross-sectional view of sidewall structure 4 resembles a quarter circle. It can be understood that a longer etching time results in a smaller diameter quarter circle, while a shorter etching time results in a larger diameter quarter circle. In other words, by controlling the etching time of the self-aligned sidewall process, the dimensions of sidewall structure 4 can be controlled, allowing for flexible adjustment of the heating resistor in the heating assembly according to actual application requirements.

[0165] A first comb structure 21 and a second comb structure 22 are formed on the upper surface of the substrate 2. The first comb structure 21 and the second comb structure 22 together constitute the conductive layer 2. The comb teeth of the first comb structure 21 and the comb teeth of the second comb structure 22 are arranged alternately. The first comb structure 21 also includes a first comb electrode 214, which is connected to the first end of the comb tooth portion of the first comb structure 21. The second comb structure 22 also includes a second comb electrode 224, which is connected to the first end of the comb tooth portion of the second comb structure 22.

[0166] Optional, such as Figure 15 as well as Figure 16 As shown, in one embodiment, the sidewall structure 4 at the intersection of the comb tooth portion of the first comb tooth structure 21 and the comb tooth portion of the second comb tooth structure 22 overlaps.

[0167] in, Figure 16 It can be regarded as Figure 15 A schematic diagram of the cross-sectional structure along the F-F' direction is shown. Through appropriate layout design, the distance between the comb teeth of the first comb tooth structure 21 and the comb teeth of the second comb tooth structure 22 is minimized. At this point, as shown... Figure 12 As shown, the sidewall structure 4 will fill the gap between the comb teeth of the first comb tooth structure 21 and the comb teeth of the second comb tooth structure 22, thereby further reducing the layout design area.

[0168] Optionally, based on the above embodiments, in one embodiment, such as Figure 14 As shown, the comb tooth portion of the first comb tooth structure 21 includes a first main comb tooth 211, a first branch comb tooth 212, and a plurality of spaced-apart second branch comb teeth 213. Each second branch comb tooth 213 is connected to the first main comb tooth 211. The first end of the first main comb tooth 211 serves as the first end of the comb tooth portion of the first comb tooth structure 21. The first branch comb teeth 212 are connected to the second branch comb teeth 213 near the second end of the first main comb tooth 211. The free end of the first branch comb tooth 212 serves as the second end of the comb tooth portion of the first comb tooth structure 21. The second comb tooth structure 22 includes a second main comb tooth 221, a third branch comb tooth 222, and a plurality of spaced fourth branch comb teeth 223. Each fourth branch comb tooth 223 is connected to the third main comb tooth. The first end of the second main comb tooth 221 serves as the first end of the comb tooth portion of the second comb tooth structure 22. The third branch comb tooth 222 is connected to the fourth branch comb tooth 223 near the second end of the second main comb tooth 221. The free end of the third branch comb tooth 222 serves as the second end of the comb tooth portion of the second comb tooth structure 22.

[0169] Based on the above embodiments, in one embodiment, please continue to refer to... Figure 14The first comb structure 21 further includes a first comb electrode 214, which is connected to the first end of the comb portion of the first comb structure 21. The second comb structure 22 further includes a second comb electrode 224, which is connected to the first end of the comb portion of the second comb structure 22.

[0170] Based on the above embodiments, in one embodiment, please continue to refer to... Figure 14 The first main comb tooth 211 and the first branch comb tooth 212 both extend along the first direction, and each second branch comb tooth 213 extends along the second direction, wherein the first direction and the second direction intersect; the second main comb tooth 221 and the third branch comb tooth 222 both extend along the first direction, and each fourth branch comb tooth 223 extends along the second direction.

[0171] The first direction can be, for example: Figure 14 The first direction is shown as a horizontal direction. Of course, in other manufacturing processes and application environments, the first direction can be other suitable directions, and this embodiment is not limited thereto; the second direction can be perpendicular to the first direction, and the second direction can be as shown in the figure. Figure 14 The vertical direction is shown in the figure. Of course, in other manufacturing processes and application environments, the second direction can be other suitable directions, and this embodiment is not limited to them.

[0172] Optionally, based on the above embodiments, in one embodiment, please continue to refer to... Figure 14 The first end of the first main comb tooth 211 is aligned with the free end of the third branch comb tooth 222; the first end of the second main comb tooth 221 is aligned with the free end of the first branch comb tooth 212. This alignment arrangement further reduces the device design area.

[0173] Based on the above embodiments, in one embodiment, such as Figure 14 As shown, the removal of the first oxide layer 7 covering the end of the sidewall structure 4 in step S206 includes: removing the first oxide layer 7 located on the surfaces of the first sidewall 41, the second sidewall 42, the third sidewall 43, and the fourth sidewall 44; wherein, the first sidewall 41 is the sidewall structure 4 at the first end of the comb tooth portion of the first comb tooth structure 21, and the second sidewall 42 is the sidewall structure 4 at the second end of the comb tooth portion of the second comb tooth structure 22; the second heating electrode 6 is respectively in contact with the third sidewall 43 located on the sidewall of the first comb tooth structure 21 and the fourth sidewall 44 located on the sidewall of the second comb tooth structure 22, wherein, the third sidewall 43 is the sidewall structure 4 at the second end of the comb tooth portion of the first comb tooth structure 21, and the fourth sidewall 44 is the sidewall structure 4 at the first end of the comb tooth portion of the second comb tooth structure 22.

[0174] Based on the above embodiments, in one embodiment, such as Figures 21 to 25 As shown, step S208 includes: forming a first heating electrode and a second heating electrode on the upper surface of the first insulating layer, forming a first sensing electrode above the first comb electrode, and forming a second sensing electrode above the second comb electrode; the first sensing electrode fills the opening corresponding to the top of the first comb electrode, and the second sensing electrode fills the opening corresponding to the top of the second comb electrode; wherein the first heating electrode is in contact with the first sidewall and the second sidewall respectively, and the second heating electrode is in contact with the third sidewall and the fourth sidewall respectively.

[0175] Figure 21 The white portion within the first comb tooth structure 21 and the second initial structure marks the location of the opening 71. However, it should be understood that... Figure 21 The opening 71 in the middle needs to expose the surfaces of the first comb structure 21 and the second comb structure 22. Figure 22 It can be regarded as Figure 21 A schematic diagram of the cross-sectional structure along the G-G' direction. Figure 23 It can be regarded as Figure 21 A schematic diagram of the cross-sectional structure along the H-H' direction. (From...) Figure 21 , Figure 22 as well as Figure 23 It can be seen that by removing the first oxide layer 7 located on the surfaces of the first sidewall 41, the second sidewall 42, the third sidewall 43, and the fourth sidewall 44, contact points can be provided for the first heating electrode 5 and the second heating electrode 6 to contact with the sidewall structure 4, thereby enabling the first heating electrode 5, the second heating electrode 6, and the sidewall structure 4 to form a complete heating assembly.

[0176] like Figure 24 as well as Figure 25 As shown, Figure 25 It can be regarded as Figure 24 The diagram shows a cross-sectional view of the structure along the I-I' direction. The materials of the first sensing electrode 8, the second sensing electrode 9, the first heating electrode 5, and the second heating electrode 6 can all be metallic electrode materials, such as copper, gold, titanium, silver, aluminum, etc., or multilayer metals composed of the above-mentioned materials, or metal alloys, etc. This embodiment does not impose any limitations. By designing a suitable photolithography pattern and performing metal deposition, photolithography, and other process steps, the first sensing electrode 8, the second sensing electrode 9, the first heating electrode 5, and the second heating electrode 6 can be formed simultaneously.

[0177] Optional, such as Figure 26 as well as Figure 27 As shown, Figure 27 for Figure 26The diagram shows the cross-sectional structure along the J-J' direction. This is for ease of understanding of the scheme. Figure 26 The circular dashed box in the figure indicates the coating area of ​​the sensitive material layer 23. Of course, the coating area and shape of the sensitive material layer 23 are not limited to this area. Figure 26 The scheme shown can be applied in practical applications by determining the coating range and shape of the sensitive material layer 23 according to the specific manufacturing process. The goal is simply to connect the toothed portions of the first comb structure 21 and the second comb structure 22 using the sensitive material layer 23. This embodiment does not impose any limitations on this. A resistance is formed by coating the sensitive material layer 23 between the toothed portions of the first and second comb structures 21 and 22, resulting in different resistance changes depending on the application scenario, thus achieving the sensing function of the corresponding sensing component. For example, the coated sensitive material layer 23 can react to a specific gas, causing a resistance change. The first sensing electrode 8 and the second sensing electrode 9 monitor the resistance change of the sensitive material layer 23, ultimately realizing the sensing function of the sensing component.

[0178] Based on the above embodiments, in one embodiment, such as Figure 17 As shown, the first heating electrode includes a first sub-electrode and a second sub-electrode, and the second heating electrode includes a third sub-electrode and a fourth sub-electrode. The above step S205 includes: forming the first sub-electrode, the second sub-electrode, the third sub-electrode and the fourth sub-electrode on the upper surface of the first insulating layer, wherein the first sub-electrode is in contact with the first sidewall; the second sub-electrode is in contact with the second sidewall; the third sub-electrode is in contact with the third sidewall; and the fourth sub-electrode is in contact with the fourth sidewall.

[0179] Additionally, it should be noted that since steps S201 to S204 of the above-described gas sensor fabrication method are similar to steps S101 to S104 of the above-described heating component fabrication method, some modified embodiments of the heating component's specific structure (e.g.) Figure 17 or Figure 18 (etc.) This also applies to gas sensors prepared using the gas sensor preparation method of the present invention. It can be understood that the structure of the gas sensor can be adapted according to the above series of modified embodiments of heating components, which will not be elaborated here.

[0180] In one embodiment, such as Figure 29 As shown, before performing step S202 above, the method for preparing the gas sensor may further include:

[0181] S2801: A second insulating layer 11 is formed on the upper surface of the substrate 1, and a third insulating layer 12 is formed on the lower surface of the substrate 1, such as... Figure 30As shown. The material of the second insulating layer 11 and the material of the third insulating layer 12 can be the same, for example, both can be silicon nitride.

[0182] S2802: A second oxide layer 13 is formed on the upper surface of the second insulating layer 11, and a third oxide layer 14 is formed on the lower surface of the third insulating layer 12. The conductive layer 2 is located on the upper surface of the second oxide layer 13. Figure 30 As shown. The material of the second oxide layer 13 and the third oxide layer 14 can be the same, for example, both can be silicon oxide. Additionally, as... Figure 30 As shown, the back hole 15 penetrates a portion of the third oxide layer 14, a portion of the third insulating layer 12, and a portion of the substrate 1 to expose a portion of the lower surface layer of the second insulating layer 11.

[0183] The second insulating layer 11 and the second oxide layer 13 serve to insulate the conductive layer 2 from the substrate 1. The third insulating layer 12 and the third oxide layer 14 can be used as a hard mask to etch and form the back hole 15.

[0184] To facilitate understanding by those skilled in the art, the fabrication method of the gas sensor provided in this application is described in detail below. Please refer to [link / reference needed]. Figure 33 The method for preparing the above-mentioned heating component may include:

[0185] S20: Provides a substrate;

[0186] S21: A second insulating layer is formed on the upper surface of the substrate, and a third insulating layer is formed on the lower surface of the substrate;

[0187] S22: A second oxide layer is formed on the upper surface of the second insulating layer, and a third oxide layer is formed on the lower surface of the third insulating layer. The conductive layer is located on the upper surface of the second oxide layer.

[0188] S23: A conductive layer is formed on the upper surface of the second oxide layer;

[0189] S24: A first insulating layer is formed on the upper surface of the conductive layer, the sidewall of the conductive layer, and the upper surface of the second oxide layer;

[0190] S25: An initial sidewall structure is formed on the surface of the first insulating layer;

[0191] S26: A portion of the initial sidewall structure is removed using a self-aligned sidewall process to form a sidewall structure; the sidewall structure includes a portion of the initial sidewall structure remaining on the sidewall of the first insulating layer after the portion of the initial sidewall structure has been removed; wherein the sidewall of the first insulating layer corresponds to the sidewall of the conductive layer.

[0192] S27: A first oxide layer is formed on the upper surface of the first insulating layer and the surface of the sidewall structure;

[0193] S28: Remove a portion of the first oxide layer to form an initial opening, and remove a portion of the first oxide layer covering the end of the sidewall structure; wherein the initial opening exposes the upper surface of the first insulating layer;

[0194] S29: The first insulating layer is removed based on the initial opening to form an opening, wherein the opening exposes the upper surface of the conductive layer;

[0195] S30: A first heating electrode and a second heating electrode are formed on the upper surface of the first insulating layer, wherein the first heating electrode and the second heating electrode are respectively in contact with the end of the sidewall structure;

[0196] S31: A first sensing electrode and a second sensing electrode are formed above the end of the conductive layer, wherein the first sensing electrode and the second sensing electrode are respectively in contact with the end of the conductive layer and partially fill the opening.

[0197] S32: A sensitive material layer is formed above the conductive layer, wherein the sensitive material layer is in contact with at least a portion of the conductive layer and fills a portion of the opening;

[0198] S33: A back hole is formed on the lower surface layer of the substrate; wherein the back hole penetrates a portion of the third oxide layer, a portion of the third insulating layer and a portion of the substrate to expose a portion of the lower surface layer of the second insulating layer.

[0199] The cross-sectional structural diagram of the gas sensor obtained after step S33 can be referenced here. Figure 28 It should be noted that the descriptions in S20-S33 above can be found in the relevant descriptions in the above embodiments, and their effects are similar. Therefore, they will not be repeated here.

[0200] It should be understood that although the steps in the flowcharts of the above embodiments are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0201] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features of the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0202] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method of producing a heating assembly, characterized by, The method comprises the following steps: providing a substrate; forming a conductive layer on the upper surface of the substrate; wherein a first comb structure and a second comb structure are formed on the upper surface of the substrate, the first comb structure and the second comb structure together constitute the conductive layer, the comb tooth portions of the first comb structure and the comb tooth portions of the second comb structure are arranged in an interlaced manner; the first comb structure further comprises a first comb electrode connected to the first end of the comb tooth portions of the first comb structure, and the second comb structure further comprises a second comb electrode connected to the first end of the comb tooth portions of the second comb structure; forming a first insulating layer on the upper surface of the conductive layer, the sidewall of the conductive layer and the upper surface of the substrate; forming a sidewall structure on the sidewall of the first insulating layer, wherein an initial sidewall structure is formed on the surface of the first insulating layer; a portion of the initial sidewall structure is removed by a self-aligned sidewall process to form the sidewall structure; the sidewall structure comprises a portion of the initial sidewall structure remaining on the sidewall of the first insulating layer after the removal of the portion of the initial sidewall structure; if the etching time is longer, the diameter of the quarter circle of the sidewall structure decreases, and if the etching time is shorter, the diameter of the quarter circle of the sidewall structure increases; wherein the sidewall of the first insulating layer corresponds to the sidewall of the conductive layer; forming a first heating electrode and a second heating electrode on the upper surface of the first insulating layer; wherein the first heating electrode and the second heating electrode are respectively arranged in contact with the end of the sidewall structure.

2. The method of claim 1, wherein the heating assembly is prepared by the steps of: The first heating electrode comprises a first sub-electrode and a second sub-electrode, and the second heating electrode comprises a third sub-electrode and a fourth sub-electrode, and the forming of the first heating electrode and the second heating electrode on the upper surface of the first insulating layer comprises: forming the first sub-electrode, the second sub-electrode, the third sub-electrode and the fourth sub-electrode on the upper surface of the first insulating layer, wherein, the first sub-electrode is arranged in contact with a first sidewall located on the sidewall of the first comb structure, and the first sidewall is the sidewall structure of the first end of the comb tooth portions of the first comb structure; the second sub-electrode is arranged in contact with a second sidewall located on the sidewall of the second comb structure, and the second sidewall is the sidewall structure of the second end of the comb tooth portions of the second comb structure; the third sub-electrode is arranged in contact with a third sidewall located on the sidewall of the first comb structure, and the third sidewall is the sidewall structure of the second end of the comb tooth portions of the first comb structure; the fourth sub-electrode is arranged in contact with a fourth sidewall located on the sidewall of the second comb structure, and the fourth sidewall is the sidewall structure of the first end of the comb tooth portions of the second comb structure.

3. A method of manufacturing a gas sensor, characterized by, The method for manufacturing the gas sensor comprises: providing a substrate; forming a conductive layer on the upper surface of the substrate; wherein a first comb structure and a second comb structure are formed on the upper surface of the substrate, the first comb structure and the second comb structure together constitute the conductive layer, wherein the comb teeth of the first comb structure and the comb teeth of the second comb structure are arranged in an interlaced manner; the first comb structure further comprises a first comb electrode connected to the first end of the comb teeth of the first comb structure, and the second comb structure further comprises a second comb electrode connected to the first end of the comb teeth of the second comb structure; forming a first insulating layer on the upper surface of the conductive layer, the sidewall of the conductive layer and the upper surface of the substrate; forming a sidewall structure on the sidewall of the first insulating layer, wherein an initial sidewall structure is formed on the surface of the first insulating layer; a portion of the initial sidewall structure is removed by a self-aligned sidewall process to form the sidewall structure; the sidewall structure comprises a portion of the initial sidewall structure remaining on the sidewall of the first insulating layer after the removal of the portion of the initial sidewall structure; if the etching time is longer, the diameter of the quarter circle of the sidewall structure decreases, and if the etching time is shorter, the diameter of the quarter circle of the sidewall structure increases; wherein the sidewall of the first insulating layer corresponds to the sidewall of the conductive layer; forming a first oxide layer on the upper surface of the first insulating layer and the surface of the sidewall structure; removing a portion of the first oxide layer to form an initial opening, and removing a portion of the first oxide layer covering the end of the sidewall structure; wherein the initial opening exposes the upper surface of the first insulating layer; removing a portion of the first insulating layer based on the initial opening to form an opening, wherein the opening exposes the upper surface of the conductive layer; forming a first heating electrode and a second heating electrode on the upper surface of the first insulating layer, wherein the first heating electrode and the second heating electrode are respectively arranged in contact with the end of the sidewall structure; forming a first sensing electrode and a second sensing electrode above the end of the conductive layer, wherein the first sensing electrode and the second sensing electrode are respectively arranged in contact with the end of the conductive layer, and fill a portion of the opening; forming a sensitive material layer above the conductive layer, wherein the sensitive material layer is arranged in contact with at least a portion of the conductive layer, and fills a portion of the opening; forming a back hole on the lower surface of the substrate.

4. The method for producing a gas sensor according to claim 3, wherein The removal of the first oxide layer covering the end of the sidewall structure comprises: removing the first oxide layer on the surface of the first sidewall, the surface of the second sidewall, the surface of the third sidewall and the surface of the fourth sidewall; wherein the first sidewall is the sidewall structure of the first end of the conductive layer, the second sidewall is the sidewall structure of the second end of the conductive layer, the third sidewall is the sidewall structure of the second end of the comb teeth of the first comb structure, and the fourth sidewall is the sidewall structure of the first end of the comb teeth of the second comb structure.

5. The method of producing a gas sensor according to claim 4, wherein The first heating electrode and the second heating electrode are formed on the upper surface of the first insulating layer, comprising: The first heating electrode and the second heating electrode are formed on the upper surface of the first insulating layer, and the first sensing electrode is formed above the first comb-shaped electrode, and the second sensing electrode is also formed above the second comb-shaped electrode; the first sensing electrode fills the opening corresponding to the top of the first comb-shaped electrode, and the second sensing electrode fills the opening corresponding to the top of the second comb-shaped electrode; wherein the first heating electrode is in contact with the first side wall and the second side wall respectively, and the second heating electrode is in contact with the third side wall and the fourth side wall respectively.

6. The method of producing a gas sensor according to claim 4, wherein The first heating electrode comprises a first sub-electrode and a second sub-electrode, and the second heating electrode comprises a third sub-electrode and a fourth sub-electrode, and the first heating electrode and the second heating electrode are formed on the upper surface of the first insulating layer, comprising: The first sub-electrode, the second sub-electrode, the third sub-electrode and the fourth sub-electrode are formed on the upper surface of the first insulating layer, wherein the first sub-electrode is in contact with the first side wall; the second sub-electrode is in contact with the second side wall; the third sub-electrode is in contact with the third side wall; and the fourth sub-electrode is in contact with the fourth side wall.

7. The method of producing a gas sensor according to claim 3, wherein Before forming the conductive layer on the upper surface of the substrate, the preparation method of the gas sensor further comprises: A second insulating layer is formed on the upper surface of the substrate, and a third insulating layer is formed on the lower surface of the substrate; A second oxidation layer is formed on the upper surface of the second insulating layer, and a third oxidation layer is formed on the lower surface of the third insulating layer, and the conductive layer is located on the upper surface of the second oxidation layer; wherein the back hole penetrates part of the third oxidation layer, part of the third insulating layer and part of the substrate to expose part of the lower surface of the second insulating layer.

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