Method of forming a pattern

Abstract

Provided are a pattern forming method, including: providing a substrate, a surface of the substrate being formed with a patterned photoresist layer; forming an isolation sidewall based on the photoresist layer, wherein the isolation sidewall includes a first sidewall close to the photoresist layer and a second sidewall away from the photoresist layer; forming a core material layer between any two adjacent isolation sidewalls; and removing the second sidewall to form the pattern composed of the first sidewall and the core material layer. The method can solve the problem of polymer blockage in the etching process caused by the reduction of the thickness of the sidewall, and can accurately form the final pattern.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and to, but is not limited to, a method for forming a pattern. Background Technology

[0002] As the integration density of semiconductor devices continues to increase, the feature size of semiconductor devices needs to be smaller and smaller. Double patterning (DP) technology is currently a key technology for realizing smaller patterns. Reverse self-aligned double patterning (RSADP) technology is widely used in the manufacture of various semiconductor devices because it can achieve excellent linewidth and pitch control.

[0003] However, in the RSADP process of related technologies, when etching to form the final pattern, the size of the etched pores becomes smaller due to the reduced thickness of the sidewall material layer (e.g., oxide). Therefore, during the sidewall etching process, polymers are easily formed on the sidewalls of the etched pores, causing blockage and making subsequent processes impossible. Summary of the Invention

[0004] In view of this, embodiments of this application provide a method for forming a pattern.

[0005] This application provides a method for forming a pattern, including:

[0006] A substrate is provided, the surface of which is formed with a patterned photoresist layer;

[0007] Based on the photoresist layer, an isolation sidewall is formed, wherein the isolation sidewall includes a first sidewall close to the photoresist layer and a second sidewall away from the photoresist layer;

[0008] A core material layer is formed between any two adjacent isolation sidewalls;

[0009] Remove the second sidewall to form the pattern consisting of the first sidewall and the core material layer.

[0010] In some embodiments, forming an isolation sidewall based on the photoresist layer includes:

[0011] A sidewall material layer is formed, the sidewall material layer being disposed on the substrate surface, the top of the photoresist layer, and the sidewall; the sidewall material layer includes a first sidewall material layer and a second sidewall material layer formed sequentially.

[0012] Remove part of the sidewall material layer until the photoresist layer and the substrate surface are exposed;

[0013] The photoresist layer is removed to form the isolation sidewall, wherein the retained first sidewall material layer forms the first sidewall, and the retained second sidewall material layer forms the second sidewall.

[0014] In some embodiments, the substrate includes a substrate or an etch stop layer on the substrate and its surface; the patterned photoresist layer is located on the surface of the etch stop layer;

[0015] The formation of the sidewall material layer includes:

[0016] A first sidewall material is deposited on the surface of the etch stop layer, on the top and sidewalls of the photoresist layer to form a first sidewall material layer;

[0017] A second sidewall material is deposited on the surface of the first sidewall material layer to form the second sidewall material layer.

[0018] In some embodiments, the first sidewall material layer has a first preset thickness, and the second sidewall material layer has a second preset thickness; wherein the first preset thickness is less than the second preset thickness.

[0019] In some embodiments, the second sidewall material has a high etching selectivity relative to the first sidewall material.

[0020] In some embodiments, after removing the second sidewall, the method further includes:

[0021] A dry etching process is used to remove a portion of the first sidewall material layer located between the second sidewall and the etching stop layer.

[0022] In some embodiments, removing a portion of the sidewall material layer until the photoresist layer and the substrate surface are exposed includes:

[0023] A dry etching process is used to etch the top of the photoresist layer and the second sidewall material layer and the first sidewall material layer on the surface of the substrate until the photoresist layer and the surface of the substrate are exposed.

[0024] In some embodiments, after forming the first sidewall material layer and before forming the second sidewall material layer, the method further includes:

[0025] A dry etching process is used to remove part of the first sidewall material layer located on the surface of the etching stop layer, while retaining the first sidewall material layer located on the sidewall of the photoresist layer.

[0026] In some embodiments, removing a portion of the sidewall material layer until the photoresist layer and the substrate surface are exposed includes:

[0027] A dry etching process is used to etch the second sidewall material layer and the first sidewall material layer on top of the photoresist layer, as well as the second sidewall material layer on the surface of the etching stop layer, until the surfaces of the photoresist layer and the etching stop layer are exposed.

[0028] In some embodiments, the patterned photoresist layer includes a plurality of initial sub-patterns arranged at intervals, with a first preset distance between two adjacent initial sub-patterns.

[0029] In some embodiments, a wet etching technique is used to remove the second sidewall to form the pattern; the pattern includes a plurality of spaced sub-patterns, with a second preset distance between adjacent sub-patterns;

[0030] Wherein, the first preset distance is greater than the second preset distance.

[0031] In some embodiments, forming a core material layer between any two adjacent isolation sidewalls includes:

[0032] An initial core material layer is formed covering the isolation sidewall, the initial core material layer being disposed on the surfaces of the etching stop layer and the isolation sidewall;

[0033] Remove a portion of the initial core material layer to form the core material layer located between any two adjacent isolation sidewalls.

[0034] In some embodiments, removing a portion of the initial core material layer to form the core material layer located between any two adjacent isolation sidewalls includes:

[0035] A dry etching process is used to etch back the initial core material layer, removing the initial core material layer located on the top surface of the isolation sidewall, exposing the top surface of the second sidewall, and forming the core material layer located between any two adjacent isolation sidewalls.

[0036] In some embodiments, removing a portion of the initial core material layer to form the core material layer located between any two adjacent isolation sidewalls includes:

[0037] The initial core material layer is subjected to chemical mechanical polishing to remove the initial core material layer located on the top surface of the isolation sidewall, exposing the top surface of the second sidewall, thus forming the core material layer located between any two adjacent isolation sidewalls.

[0038] In some embodiments, the first sidewall material is the same as the core material, or the first sidewall material has the same etching selectivity relative to the core material.

[0039] The pattern formation method provided in this application includes providing a substrate, the surface of which is at least formed with a patterned photoresist layer; forming isolation sidewalls based on the photoresist layer, the isolation sidewalls including a first sidewall close to the photoresist layer and a second sidewall away from the photoresist layer; forming a core material layer between any two adjacent isolation sidewalls; and removing the second sidewall to form a pattern composed of the first sidewall and the core material layer. The pattern formation method of this application can solve the problem of polymer blockage in the etching process caused by the reduction of sidewall thickness in related technologies, and can accurately form the final pattern. Attached Figure Description

[0040] In the accompanying drawings (which are not necessarily drawn to scale), similar reference numerals may describe similar parts in different views. Similar reference numerals with different letter suffixes may indicate different examples of similar parts. The drawings illustrate, by way of example and not limitation, the various embodiments discussed herein.

[0041] Figures 1a-1e This is a process flow diagram of the reverse self-aligned dual imaging technology in related technologies.

[0042] Figure 2 A schematic flowchart of an optional method for forming a pattern provided in an embodiment of this application;

[0043] Figures 3a-3i An optional flowchart for forming a pattern provided in an embodiment of this application;

[0044] Figures 4a-4i Another optional flowchart for forming a pattern provided in an embodiment of this application;

[0045] The annotations in the attached figures are explained as follows:

[0046] 101 / 300 / 400—Substrate; 102 / 301 / 401—Etching stop layer; 103 / 305a—Core material layer; 104—First mask layer; 105—Dielectric layer; 302 / 402—Photoresist layer; 106—Sidewall material layer; 107—Second mask layer; 302a / 302b / 302c—Initial subpattern; 303 / 403—First sidewall material layer; 303a / 403a—First sidewall; 304 / 404—Second sidewall material layer; 304a / 404a—Second sidewall; 305 / 405—Initial core material layer; 306 / 406—Pattern; 306a / 306b / 306c / 306d / 306e—Subpattern; 305a / 405a—Core material layer. Detailed Implementation

[0047] Exemplary embodiments of the present application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application may be implemented in various forms and should not be limited to the specific embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present application and to fully convey the scope of the disclosure of the present application to those skilled in the art.

[0048] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of this application. However, it will be apparent to those skilled in the art that this application can be practiced without one or more of these details. In other instances, to avoid confusion with this application, some technical features well-known in the art have not been described; that is, not all features of actual embodiments are described herein, nor are well-known functions and structures described in detail.

[0049] In the accompanying drawings, for clarity, the dimensions of layers, areas, and elements, as well as their relative dimensions, may be exaggerated. The same reference numerals denote the same elements throughout.

[0050] 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, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this application, the first element, component, area, layer, or portion discussed below may be referred to as a second element, component, area, layer, or portion. And the discussion of a second element, component, area, layer, or portion does not imply that the first element, component, area, layer, or portion necessarily exists in this application.

[0051] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description 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 are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below,” “under,” or “below” other elements or features will be oriented “above” other elements or features. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0052] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0053] Figures 1a-1e This is a process flow diagram of the reverse self-aligned dual imaging technology in related technologies. Before detailing the pattern formation method of the embodiments of this application, please first refer to... Figures 1a-1d This paper introduces the reverse self-aligned dual imaging technology in related technologies.

[0054] like Figure 1a As shown, a substrate 101 is provided, on which an etch stop layer 102, a core material layer 103, a patterned first mask layer 104, and a dielectric layer 105 are sequentially formed. The etch stop layer 102 may be a silicon oxynitride layer, the core material layer 103 may be an oxide layer, the first mask layer 104 may be a spin-on carbon (SOC) layer, the patterned first mask layer includes multiple spaced patterns, and the dielectric layer 105 is located on the surface of the patterned mask layer 104; the dielectric layer 105 may also be a silicon oxynitride layer. Figure 1bAs shown, a sidewall material layer 106 is formed on the surface of the core material layer 103, the sidewall of the patterned first mask layer 104, and the surface of the dielectric layer 105. The sidewall material layer 106 may be made of the same material as the core material layer 103 or a different material. For example, the sidewall material layer 106 may also be an oxide layer.

[0055] Next, as Figure 1c As shown, a mask material is deposited and processed on the surface of the sidewall material layer 106 to form a second mask layer 107. The second mask layer 107 is alternately arranged with the first mask layer 104, and the surface of the second mask layer 107 is flush with the surface of the sidewall material layer 106. The second mask layer 107 can also be a spin-coated carbon layer. Figure 1d As shown, the sidewall material layer and the corresponding core material layer between the first mask layer 104 and the second mask layer 107 are etched until the surface of the etching stop layer 102 is exposed, so as to form the final pattern in the core material layer 103.

[0056] However, during the etching process to form the final pattern, due to the poor conformability of the photoresist, polymer B easily forms in the etched apertures A. Furthermore, the reduced thickness of the sidewall material layer results in smaller aperture sizes in A, making it difficult to remove the formed polymer B within the apertures, leading to blockage and the formation of patterns such as... Figure 1e The pattern shown is not formed; and because polymer B blocks the etched pores A, subsequent processes cannot be completed, thus the final accurate pattern cannot be formed.

[0057] In view of the above-mentioned problems existing in related technologies, this application provides a method for forming a pattern. Figure 2 This is a schematic flowchart of an optional method for forming a pattern provided in an embodiment of this application, such as... Figure 2 As shown, the method includes the following steps:

[0058] Step S201: Provide a substrate, the surface of which is formed with a patterned photoresist layer.

[0059] In this embodiment, the substrate may be a base. In other embodiments, the base is a silicon base. Furthermore, the base may include other semiconductor elements, such as germanium, or semiconductor compounds, such as silicon carbide, gallium arsenide, gallium phosphide, indium phosphide, indium arsenide, or indium antimonide, or other semiconductor alloys, such as silicon germanium, gallium arsenide phosphide, indium aluminum arsenide, gallium aluminum arsenide, indium gallium arsenide, indium gallium phosphide, and / or indium gallium arsenide phosphide or combinations thereof.

[0060] In other embodiments, the substrate may further include a base and an etch stop layer disposed on the surface of the base, wherein the material of the etch stop layer may be silicon carbide, silicon oxide, silicon nitride, or silicon oxynitride.

[0061] In this embodiment, the patterned photoresist layer is located on the surface of the etch stop layer; in other embodiments, the patterned photoresist layer may also be located on the surface of the substrate.

[0062] The patterned photoresist layer includes multiple initial sub-patterns arranged at intervals. In this embodiment, reverse self-aligned dual imaging technology is achieved through multiple initial sub-patterns arranged at intervals.

[0063] Step S202: Based on the photoresist layer, an isolation sidewall is formed.

[0064] The isolation sidewall includes a first sidewall close to the photoresist layer and a second sidewall away from the photoresist layer.

[0065] In this embodiment, after the isolation sidewall is formed based on the photoresist layer, the photoresist layer is removed. The formed isolation sidewall comprises two layers: a first sidewall and a second sidewall. The second sidewall is located outside the first sidewall relative to each initial sub-pattern in the photoresist layer. Here, the first and second sidewalls may be in contact with each other.

[0066] Step S203: Form a core material layer between any two adjacent isolation sidewalls.

[0067] In this embodiment, the core material layer is used to form the final etching pattern. The core material layer may be an oxide layer, a spin-coated carbon layer, or other material layers.

[0068] Step S204: Remove the second sidewall to form the pattern consisting of the first sidewall and the core material layer.

[0069] The pattern formation method provided in this application can solve the problem of polymer blockage in the etching process caused by the reduction of sidewall thickness in related technologies, and can accurately form the final pattern.

[0070] Figures 3a-3i This is a schematic diagram of an optional pattern forming process provided in an embodiment of this application. Please refer to the following. Figures 3a-3i The method for forming patterns provided in the embodiments of this application will be described in further detail.

[0071] First, you can refer to Figure 3a Step S201 is performed, providing a substrate, the surface of which is at least formed with a patterned photoresist layer.

[0072] like Figure 3a As shown, the substrate includes a base 300 and an etch stop layer 301 located on the surface of the base. A patterned photoresist layer 302 is formed on the surface of the etch stop layer 301 in the substrate. The etch stop layer 301 can be a silicon carbide layer, a silicon oxide layer, a silicon nitride layer, a silicon oxynitride layer, a polysilicon layer, or other material layers. The patterned photoresist layer 302 includes a plurality of initially arranged sub-patterns (e.g., 302a, 302b, and 302c), and the spacing between two adjacent initial sub-patterns can be the same or different. In the embodiments of this application, the initial sub-patterns are equally spaced, for example, there is a first preset distance w1 between two adjacent initial sub-patterns.

[0073] Next, you can refer to Figures 3b-3f In step S202, an isolation sidewall is formed based on the photoresist layer.

[0074] In some embodiments, step S202 can be implemented through the following steps:

[0075] Step S2021: Form a sidewall material layer, wherein the sidewall material layer is disposed on the substrate surface, the top of the photoresist layer and the sidewall; the sidewall material layer includes a first sidewall material layer and a second sidewall material layer formed sequentially.

[0076] The first sidewall material layer is close to the photoresist layer, and the second sidewall material layer is far from the photoresist layer; the first sidewall material layer and the second sidewall material layer are in contact with each other.

[0077] In some embodiments, the substrate includes a substrate or an etch stop layer on the substrate and its surface; the patterned photoresist layer is located on the surface of the etch stop layer; step S2021 may include the following steps:

[0078] Step S1: Deposit a first sidewall material on the surface of the etch stop layer, on the top and sidewalls of the photoresist layer to form the first sidewall material layer.

[0079] In this embodiment, chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), spin coating, coating, or other processes can be used to deposit the first sidewall material to form the first sidewall material layer.

[0080] like Figure 3bAs shown, a first sidewall material is deposited on the surface of the etch stop layer 301 and on the top and sidewalls of the patterned photoresist layer, forming a first sidewall material layer 303. The first sidewall material can be an oxide, a carbon material, or other materials.

[0081] Step S2: Using a dry etching process, a portion of the first sidewall material layer located on the surface of the etching stop layer is removed, while the first sidewall material layer located on the surface of the photoresist layer is retained.

[0082] The dry etching process can be plasma etching, reactive ion etching, or ion milling.

[0083] like Figure 3c As shown, a portion of the first sidewall material layer on the surface of the etch stop layer 301 was removed, exposing the surface of the etch stop layer 301, while the first sidewall material layer 303 on the surface of the photoresist layer was retained.

[0084] Step S3: Deposit a second sidewall material on the surface of the etching stop layer and the first sidewall material layer to form the second sidewall material layer.

[0085] Here, any suitable deposition process can be used to deposit the second sidewall material on the surface of the etch stop layer and the first sidewall material layer. The second sidewall material can be silicon nitride, silicon oxynitride, or other materials.

[0086] In some embodiments, the thickness of the second sidewall material layer is greater than the thickness of the first sidewall material layer.

[0087] In this embodiment, the second sidewall material has a high etching selectivity relative to the first sidewall material, meaning that under the same etching conditions, the second sidewall material is easier to remove.

[0088] like Figure 3d As shown, a second sidewall material is deposited on the surface of the etching stop layer 301 and the first sidewall material layer 303 to form a second sidewall material layer 304.

[0089] Step S2022: Remove part of the sidewall material layer until the photoresist layer and the substrate surface are exposed.

[0090] In some embodiments, in step S2022, removing part of the sidewall material layer means removing the second sidewall material layer on the surface of the substrate and the second sidewall material layer and the first sidewall material layer on top of the photoresist layer, while retaining the second sidewall material layer and the first sidewall material layer on the sidewall of the photoresist layer.

[0091] In some embodiments, removing a portion of the sidewall material layer until the photoresist layer and the substrate surface are exposed includes: using a dry etching process to etch the second sidewall material layer on the substrate surface and the second sidewall material layer and the first sidewall material layer on top of the photoresist layer until the photoresist layer and the substrate surface are exposed.

[0092] In other embodiments, chemical mechanical polishing (CMP) can also be used to remove the second sidewall material layer and the first sidewall material layer on top of the photoresist layer.

[0093] like Figure 3e As shown, the second sidewall material layer and the first sidewall material layer located on top of the photoresist layer are removed, and the second sidewall material layer on the surface of the etch stop layer 301 is also removed, exposing the surfaces of the photoresist layer and the etch stop layer 303. The second sidewall material layer and the first sidewall material layer located on the sidewalls of the photoresist layer are retained, wherein the retained first sidewall material layer forms the first sidewall 303a, and the retained second sidewall material layer forms the second sidewall 304a.

[0094] In some embodiments, the second sidewall material has a high etch selectivity relative to the etch stop layer material, meaning that the second sidewall material is easier to remove than the etch stop layer material.

[0095] Step S2023: Remove the photoresist layer to form the isolation sidewall.

[0096] like Figure 3f As shown, the photoresist layer located between adjacent first sidewalls 303a was removed, forming an isolation sidewall.

[0097] Here, the photoresist layer can be removed using either dry etching or wet etching techniques.

[0098] Next, you can refer to Figure 3g and 3h Then, perform step S203 to form a core material layer between any two adjacent isolation sidewalls.

[0099] In some embodiments, step S203 may include the following steps:

[0100] Step S2031: Form an initial core material layer covering the isolation sidewall, the initial core material layer being disposed on the surface of the etching stop layer and the isolation sidewall.

[0101] In this embodiment, any suitable deposition process can be used to form the initial core material layer. For example, spin coating.

[0102] In some embodiments, the core material and the first sidewall material of the first sidewall material layer may be the same or different. When the core material and the first sidewall material are different, the first sidewall material has the same etching selectivity relative to the core material. That is, when the core material and the first sidewall material are different, the core material and the first sidewall material can be removed simultaneously under the same etching conditions.

[0103] like Figure 3g As shown, a core material is deposited on the surfaces of the etching stop layer 301 and the isolation sidewall to form an initial core material layer 305 covering the isolation sidewall. In this embodiment, the core material is the same as the first sidewall material constituting the first sidewall 303a.

[0104] Step S2031: Remove a portion of the initial core material layer to form the core material layer located between any two adjacent isolation sidewalls. In some embodiments, step S2031 can be implemented in the following two ways:

[0105] Method 1: Using a dry etching process, the initial core material layer is etched back to remove the initial core material layer located on the top surface of the isolation sidewall, exposing the top surface of the second sidewall, thus forming the core material layer located between any two adjacent isolation sidewalls.

[0106] Method 2: Perform chemical mechanical polishing on the initial core material layer to remove the initial core material layer located on the top surface of the isolation sidewall, exposing the top surface of the second sidewall, and forming the core material layer located between any two adjacent isolation sidewalls.

[0107] like Figure 3h As shown, the initial core material layer on the top surface of the isolation sidewall is removed by dry etching or chemical mechanical polishing (CMP) to form a core material layer 305a located between any two adjacent isolation sidewalls.

[0108] Next, you can refer to Figure 3i Step S204 is executed to remove the second sidewall, forming the pattern composed of the first sidewall and the core material layer.

[0109] In this embodiment, a wet etching technique can be used to remove the second sidewall. For example, a pre-set etching solution can be used to etch and remove the second sidewall. The pre-set etching solution can be a phosphoric acid solution, a hydrofluoric acid solution, or a sulfuric acid solution.

[0110] like Figure 3iAs shown, the second sidewall 304a is removed to form a pattern 306 consisting of the first sidewall 303a and the core material layer 305a.

[0111] In this embodiment of the application, the pattern 306 includes multiple sub-patterns arranged at intervals (e.g., 306a, 306b, 306c, 306d, and 306e), and there is a second preset distance w2 between adjacent sub-patterns. The first preset distance w1 is greater than the second preset distance w2.

[0112] In this embodiment, three initial sub-patterns 302a, 302b, and 302c are used to form five sub-patterns 306a, 306b, 306c, 306d, and 306e through reverse self-aligned dual imaging technology. In this way, without changing the size of the photolithography window, a minimum size of 3 / 5 can be achieved, thereby improving the density of semiconductor integrated circuits.

[0113] In this embodiment, since the first preset thickness of the first sidewall material layer forming the first sidewall is less than the second preset thickness of the second sidewall material layer forming the second sidewall, the spacing between the sub-patterns in the final pattern is more appropriate, which facilitates the subsequent formation of other structures on the final pattern.

[0114] This application proposes a novel RSADP process that utilizes a polysilicon stop layer and a dry or wet etching process (air gap formation process) similar to that used for NON structures. This optimizes the problem of reduced sidewall material layer thickness in the RSADP process of related technologies, which leads to polymer blockage during sidewall etching.

[0115] Figures 4a-4i The following is a schematic diagram of another optional process for forming a pattern according to an embodiment of this application. Please refer to the following. Figures 4a-4i The method for forming patterns provided in the embodiments of this application will be described in further detail.

[0116] First, you can refer to Figure 4a Step S201 is performed, providing a substrate on which a patterned photoresist layer is formed on the surface.

[0117] In this embodiment of the application, the substrate may include a substrate, or it may include a substrate and an etch stop layer disposed on the surface of the substrate.

[0118] like Figure 4a As shown, the substrate includes a base 400 and an etch stop layer 401 located on the surface of the base. A patterned photoresist layer 302 is formed on the surface of the etch stop layer 401 in the substrate. The patterned photoresist layer 402 includes a plurality of initially arranged sub-patterns at intervals.

[0119] In this embodiment, the substrate 400, the etch stop layer 401, and the patterned photoresist layer 402 are similar to the substrate 300, the etch stop layer 301, and the patterned photoresist layer 302 in the above embodiments, and will not be described again here.

[0120] Next, you can refer to Figures 4b-4e In step S202, an isolation sidewall is formed based on the photoresist layer.

[0121] In some embodiments, step S202 can be implemented through the following steps:

[0122] Step S2021: Form a sidewall material layer, wherein the sidewall material layer is disposed on the substrate surface, the top of the photoresist layer and the sidewall; the sidewall material layer includes a first sidewall material layer and a second sidewall material layer formed sequentially.

[0123] The first sidewall material layer is close to the photoresist layer, and the second sidewall material layer is far from the photoresist layer; the first sidewall material layer and the second sidewall material layer are in contact with each other.

[0124] In some embodiments, step S2021 may include the following steps:

[0125] Step S1: Deposit a first sidewall material on the surface of the etch stop layer, on the top and sidewalls of the photoresist layer to form the first sidewall material layer.

[0126] In this embodiment of the application, CVD, PVD, ALD, spin coating, coating or other processes can be used to deposit the first sidewall material to form the first sidewall material layer.

[0127] like Figure 4b As shown, a first sidewall material is deposited on the surface of the etch stop layer 401 and on the top and sidewalls of the photoresist layer 402, forming a first sidewall material layer 403. The first sidewall material can be an oxide, a carbon material, or other materials. In this embodiment, the first sidewall material layer has a first preset thickness h1.

[0128] Step S2: Deposit a second sidewall material on the surface of the first sidewall material layer to form the second sidewall material layer.

[0129] The second sidewall material can be silicon nitride, silicon oxynitride, or other materials.

[0130] like Figure 4cAs shown, a second sidewall material is deposited on the surface of the first sidewall material layer 403 to form a second sidewall material layer 404. The second sidewall material layer has a second preset thickness h2; wherein, the first preset thickness h1 is smaller than the second preset thickness h2.

[0131] In this embodiment, the second sidewall material has a high etching selectivity relative to the first sidewall material, meaning that under the same etching conditions, the second sidewall material is easier to remove.

[0132] Step S2022: Remove part of the sidewall material layer until the photoresist layer and the substrate surface are exposed.

[0133] In some embodiments, removing a portion of the sidewall material layer until the photoresist layer and the substrate surface are exposed includes: using a dry etching process to etch the substrate surface and the second sidewall material layer and the first sidewall material layer on top of the photoresist layer until the photoresist layer and the substrate surface are exposed.

[0134] In other embodiments, chemical mechanical polishing (CMP) can also be used to remove the second sidewall material layer and the first sidewall material layer on top of the photoresist layer.

[0135] like Figure 4d As shown, the second sidewall material layer and the first sidewall material layer located on top of the photoresist layer are removed, and the second sidewall material layer and the first sidewall material layer on the surface of the etch stop layer 401 are also removed, exposing the surfaces of the photoresist layer and the etch stop layer 401. The second sidewall material layer and the first sidewall material layer located on the sidewalls of the photoresist layer are retained, wherein the retained first sidewall material layer forms the first sidewall 403a, and the retained second sidewall material layer forms the second sidewall 404a.

[0136] In some embodiments, the second sidewall material has a high etch selectivity relative to the etch stop layer material, meaning that the second sidewall material is easier to remove than the etch stop layer material.

[0137] Step S2023: Remove the photoresist layer to form the isolation sidewall.

[0138] like Figure 4e As shown, the photoresist layer located between adjacent first sidewalls 403a was removed, forming an isolation sidewall.

[0139] Next, you can refer to Figure 4f and 4g Then, perform step S203 to form a core material layer between any two adjacent isolation sidewalls.

[0140] In this embodiment, the implementation process of step S203 is the same as that of step S203 in the above embodiments. For the technical features disclosed in this embodiment in detail, please refer to the above embodiments for understanding. Here, they will not be repeated.

[0141] like Figure 4f As shown, core material is deposited on the surfaces of the etching stop layer 401 and the isolation sidewalls to form an initial core material layer 405 covering the isolation sidewalls. In this embodiment, the core material is the same as the first sidewall material constituting the first sidewall 403a. Figure 4g As shown, the initial core material layer located on the top surface of the isolation sidewall is removed to form a core material layer 405a located between any two adjacent isolation sidewalls.

[0142] Next, you can refer to Figure 4h and 4i Step S204 is executed to remove the second sidewall, forming the pattern composed of the first sidewall and the core material layer.

[0143] In this embodiment, a wet etching technique can be used to remove the second sidewall. For example, a pre-set etching solution can be used to etch and remove the second sidewall. The pre-set etching solution can be a phosphoric acid solution, a hydrofluoric acid solution, or a sulfuric acid solution.

[0144] like Figure 4h As shown, the second sidewall 404a is removed to form a pattern composed of the first sidewall 403a and the core material layer 405a. The pattern formed at this time is not the final pattern.

[0145] In some embodiments, after removing the second sidewall, the method of forming the pattern further includes the following steps:

[0146] Step S205: A dry etching process is used to remove a portion of the first sidewall material layer located between the second sidewall and the etching stop layer.

[0147] The dry etching process can be plasma etching, reactive ion etching, or ion milling. In this embodiment, plasma etching is used to remove a portion of the first sidewall material layer between the second sidewall and the etching stop layer.

[0148] like Figure 4h and 4i As shown, the wall located on the second side wall (which has already been removed, i.e., the corresponding wall) has been removed. Figure 4i The portion of the first sidewall material layer 403a-1 between the pore location in the middle and the etching stop layer 401, the retained first sidewall material layer 403a-2 and the core material layer 405a constitute the final pattern 406.

[0149] In this embodiment, since the first preset thickness of the first sidewall material layer forming the first sidewall is less than the second preset thickness of the second sidewall material layer forming the second sidewall, the spacing between the sub-patterns in the final pattern is more appropriate, which facilitates the subsequent formation of other structures on the final pattern.

[0150] In this embodiment, the pattern 406 formed is the same as the pattern 306 formed in the above embodiment. Please refer to the above embodiment for a detailed understanding.

[0151] The pattern formation method of this application can solve the problem of polymer blockage in the etching process caused by the reduction of sidewall thickness in related technologies, and can accurately form the final pattern.

[0152] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in a non-target manner. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple units or components may be combined, or integrated into another system, or some features may be ignored or not executed. In addition, the various components shown or discussed are coupled to each other or directly coupled.

[0153] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units may be selected to achieve the purpose of this embodiment according to actual needs.

[0154] The features disclosed in the several method or device embodiments provided in this application can be arbitrarily combined without conflict to obtain new method or device embodiments.

[0155] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for forming a pattern, characterized in that, The method includes: A substrate is provided, the surface of which is formed with a patterned photoresist layer; A sidewall material layer is formed, wherein the sidewall material layer is disposed on the substrate surface, the top of the photoresist layer and the sidewall, wherein the sidewall material layer includes a first sidewall material layer and a second sidewall material layer formed sequentially; Remove part of the sidewall material layer until the photoresist layer and the substrate surface are exposed; Remove the photoresist layer to form an isolation sidewall, wherein the retained first sidewall material layer forms a first sidewall and the retained second sidewall material layer forms a second sidewall, and the isolation sidewall includes the first sidewall and the second sidewall; A core material layer is formed between any two adjacent isolation sidewalls, wherein the core material layer includes a first portion located between two adjacent first sidewalls and a second portion located between two adjacent second sidewalls, the first portion occupying the original location of the removed photoresist layer; The second sidewall is removed to form the pattern, wherein the pattern includes a first pattern consisting of the first portion and two adjacent first sidewalls, and a second pattern consisting of the second portion.

2. The method according to claim 1, characterized in that, The substrate includes a substrate or an etch stop layer on the substrate and its surface; The patterned photoresist layer is located on the surface of the etch stop layer; The formation of the sidewall material layer includes: A first sidewall material is deposited on the surface of the etch stop layer, on the top and sidewalls of the photoresist layer to form a first sidewall material layer; A second sidewall material is deposited on the surface of the first sidewall material layer to form the second sidewall material layer.

3. The method according to claim 2, characterized in that, The first sidewall material layer has a first preset thickness, and the second sidewall material layer has a second preset thickness; Wherein, the first preset thickness is less than the second preset thickness.

4. The method according to claim 2, characterized in that, The second sidewall material has a high etching selectivity relative to the first sidewall material.

5. The method according to any one of claims 2 to 4, characterized in that, After removing the second sidewall, the method further includes: A dry etching process is used to remove a portion of the first sidewall material layer located between the second sidewall and the etching stop layer.

6. The method according to claim 5, characterized in that, The removal of a portion of the sidewall material layer until the photoresist layer and the substrate surface are exposed includes: A dry etching process is used to etch the top of the photoresist layer and the second sidewall material layer and the first sidewall material layer on the surface of the substrate until the photoresist layer and the surface of the substrate are exposed.

7. The method according to any one of claims 2 to 4, characterized in that, After forming the first sidewall material layer and before forming the second sidewall material layer, the method further includes: A dry etching process is used to remove a portion of the first sidewall material layer located on the surface of the etching stop layer, while retaining the first sidewall material layer located on the surface of the photoresist layer.

8. The method according to claim 7, characterized in that, The removal of a portion of the sidewall material layer until the photoresist layer and the substrate surface are exposed includes: A dry etching process is used to etch the second sidewall material layer and the first sidewall material layer on top of the photoresist layer, as well as the second sidewall material layer on the surface of the etching stop layer, until the surfaces of the photoresist layer and the etching stop layer are exposed.

9. The method according to any one of claims 1 to 4, characterized in that, The patterned photoresist layer includes multiple initial sub-patterns arranged at intervals, with a first preset distance between two adjacent initial sub-patterns.

10. The method according to claim 9, characterized in that, The second sidewall is removed using a wet etching technique to form the pattern; the pattern includes multiple spaced sub-patterns, with a second preset distance between adjacent sub-patterns; Wherein, the first preset distance is greater than the second preset distance.

11. The method according to any one of claims 2 to 4, characterized in that, The formation of a core material layer between any two adjacent isolation sidewalls includes: An initial core material layer is formed covering the isolation sidewall, the initial core material layer being disposed on the surfaces of the etching stop layer and the isolation sidewall; Remove a portion of the initial core material layer to form the core material layer located between any two adjacent isolation sidewalls.

12. The method according to claim 11, characterized in that, The removal of a portion of the initial core material layer to form the core material layer located between any two adjacent isolation sidewalls includes: A dry etching process is used to etch back the initial core material layer, removing the initial core material layer located on the top surface of the isolation sidewall, exposing the top surface of the second sidewall, and forming the core material layer located between any two adjacent isolation sidewalls.

13. The method according to claim 11, characterized in that, The removal of a portion of the initial core material layer to form the core material layer located between any two adjacent isolation sidewalls includes: The initial core material layer is subjected to chemical mechanical polishing to remove the initial core material layer located on the top surface of the isolation sidewall, exposing the top surface of the second sidewall, thus forming the core material layer located between any two adjacent isolation sidewalls.

14. The method according to claim 12 or 13, characterized in that, The first sidewall material is the same as the core material, or the first sidewall material has the same etching selectivity relative to the core material.

Images