Method for preparing photoresist layer

Abstract

The present application discloses a method for preparing a photoresist layer, which comprises: providing a substrate; forming a first photoresist layer on the substrate; and processing the first photoresist layer to form a second photoresist layer containing a graft copolymer. The second photoresist layer containing the graft copolymer is formed by processing the first photoresist layer after the first photoresist layer is formed. Since the second photoresist layer contains the graft copolymer, the adhesion of the second photoresist layer and the interface strength of the photoresist layer are improved, thereby reducing the risk of collapse of the second photoresist layer and improving the reliability of device quality.

Description

Technical Field

[0001] The invention relates to the field of semiconductor technology, and in particular to a method for preparing a photoresist layer. Background Art

[0002] Photolithography technology is a very important link in the field of semiconductor manufacturing. As process nodes become smaller and smaller, critical dimensions are also getting smaller and smaller, and the difficulty of photolithography is also increasing, which in turn increases the risk of photoresist lines bending, breaking, losing adhesion to the substrate, and collapsing on the wafer surface, affecting product quality. Summary of the invention

[0003] A series of simplified concepts are introduced in the Summary of the Invention, which will be further described in detail in the Detailed Description of the Invention. The Summary of the Invention does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0004] In view of the existing problems, an embodiment of the present invention provides a method for preparing a photoresist layer, comprising:

[0005] providing a substrate;

[0006] forming a first photoresist layer on the substrate;

[0007] The first photoresist layer is processed to form a second photoresist layer containing a graft copolymer.

[0008] Exemplarily, the processing of the first photoresist layer to form a second photoresist layer containing a graft copolymer includes:

[0009] performing plasma treatment on the first photoresist layer to form free radicals in the first photoresist layer;

[0010] A curing solution is coated on the first photoresist layer after the plasma treatment, so that the first photoresist layer and the curing solution undergo copolymerization reaction to form a second photoresist layer containing a graft copolymer.

[0011] Exemplarily, the preparation method further comprises:

[0012] The following steps are repeatedly performed in sequence: forming a first photoresist layer on the substrate; and processing the first photoresist layer to form a second photoresist layer containing a graft copolymer until the thickness of the second photoresist layer reaches a predetermined thickness.

[0013] Exemplarily, the plasma treatment adopts at least one of the following treatment methods: corona discharge plasma treatment, glow discharge plasma treatment, spark discharge plasma treatment, dielectric barrier discharge plasma treatment, sliding arc discharge plasma treatment, microwave plasma treatment and radio frequency plasma treatment.

[0014] Exemplarily, the electron temperature range of the plasma treatment is 0K-10 4 K.

[0015] Exemplarily, when the plasma treatment adopts glow discharge plasma treatment and / or radio frequency plasma treatment, the gas temperature range of the glow discharge plasma treatment is 0K-500K, and the gas temperature range of the radio frequency plasma treatment is 0K-500K.

[0016] Exemplarily, when the plasma treatment adopts corona discharge plasma treatment and / or microwave plasma treatment, the gas temperature range of the corona discharge plasma treatment is 0K-300K, and the gas temperature range of the microwave plasma treatment is 0K-800K.

[0017] Illustratively, the curing solution includes a solvent and an additive.

[0018] Exemplarily, the solvent includes at least one functional group of -X, -OH, -CHO, -NO2, -SO3H, -NH2, RCO-.

[0019] Exemplarily, the preparation method further comprises:

[0020] covering the second photoresist layer with a mask;

[0021] exposing the second photoresist layer through the mask;

[0022] The second photoresist layer is developed to form a patterned photoresist layer.

[0023] The method for preparing a photoresist layer provided by the present invention forms a second photoresist layer containing a graft copolymer by processing the first photoresist layer after the first photoresist layer is formed. Since the second photoresist layer contains the graft copolymer, the adhesion of the second photoresist layer and the interface strength of the photoresist layer are improved, thereby reducing the risk of collapse of the second photoresist layer and improving the reliability of device quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The following drawings of the present invention are used as part of the present invention for understanding the present invention. The drawings show embodiments of the present invention and their descriptions to explain the principles of the present invention. In the drawings:

[0025] Figure 1A schematic flow chart showing a method for preparing a photoresist layer according to a specific embodiment of the present invention;

[0026] FIG. 2A to FIG. 2F The cross-sectional schematic diagram of a semiconductor structure obtained by sequentially implementing each step of a method for preparing a photoresist layer according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0027] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present invention. However, it is apparent to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features well known in the art are not described.

[0028] It should be understood that the present invention can be implemented in different forms and should not be construed as being limited to the embodiments presented herein. On the contrary, providing these embodiments will make the disclosure thorough and complete and fully convey the scope of the present invention to those skilled in the art. In the accompanying drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity. The same reference numerals throughout represent the same elements.

[0029] It should be understood that when an element or layer is referred to as being "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. In contrast, when an element is referred to as being "directly on, directly adjacent to, directly connected to or directly coupled to other elements or layers, there may be 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, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present invention, the first element, component, region, layer or part discussed below may be represented as a second element, component, region, layer or part.

[0030] Spatially relative terms such as "under," "below," "below," "under," "above," "above," etc., may be used herein for ease of description to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that in addition to the orientations shown in the figures, the spatially relative terms are intended to include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is flipped, then the elements or features described as "under other elements" or "under" or "under" will be oriented as "on" the other elements or features. Therefore, the exemplary terms "under" and "under" may include both upper and lower orientations. The device may be oriented otherwise (rotated 90 degrees or other orientations) and the spatial descriptors used herein are interpreted accordingly.

[0031] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present invention. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0032] Photolithography is a very important part of semiconductor manufacturing. During the photolithography process, the pattern in the mask can be transferred to the photoresist layer to form a photoresist mask, through which the surface layer of the semiconductor substrate can be patterned. Usually, the photolithography process is repeated many times in the semiconductor manufacturing process.

[0033] As process nodes become smaller and smaller, key feature sizes are also getting smaller and smaller. Photolithography technology is also constantly developing, and the photoresist mask patterns formed will become more and more refined. The contact area between the photoresist and the surface may be very small, making the difficulty of photolithography increasing. This in turn increases the risk of photoresist lines bending, breaking, losing adhesion to the substrate, and collapsing on the wafer surface, affecting product quality.

[0034] Photoresist collapse is one of the common defects in photolithography technology. The improvement methods in related technologies, on the one hand, improve the function of the equipment itself. For example, adding a soft drying after coating and hard drying after development can greatly improve the phenomenon of photoresist collapse. On the other hand, it can also be improved from the process. In the related technologies for process improvement, a layer of oxide, such as silicon dioxide, is usually deposited first, and then the oxide is simply pickled to increase the roughness of the oxide surface. The photoresist is coated on the rougher oxide, which can increase the interface strength of the photoresist layer, thereby improving the photoresist collapse phenomenon.

[0035] In view of the problem of photoresist layer collapse, the embodiment of the present invention provides a method for preparing a photoresist layer, such as Figure 1 As shown, it mainly includes the following steps:

[0036] Step S110: providing a substrate;

[0037] Step S120: forming a first photoresist layer on the substrate;

[0038] Step S130: processing the first photoresist layer to form a second photoresist layer containing a graft copolymer.

[0039] The method for preparing a photoresist layer provided by the present invention forms a second photoresist layer containing a graft copolymer by processing the first photoresist layer after the first photoresist layer is formed. Since the second photoresist layer contains the graft copolymer, the adhesion of the second photoresist layer and the interface strength of the photoresist layer are improved, thereby reducing the risk of collapse of the second photoresist layer and improving the reliability of device quality.

[0040] Below, reference FIG. 2A to FIG. 2F The method for preparing the photoresist layer of the embodiment of the present invention is described in detail, wherein: FIG. 2A to FIG. 2F The cross-sectional schematic diagram of a semiconductor structure obtained by sequentially implementing each step of a method for preparing a photoresist layer according to an embodiment of the present invention is shown.

[0041] First, step S110 is performed to provide a substrate.

[0042] like Figure 2AAs shown, a substrate 200 is provided, which can be a semiconductor substrate. The material of the substrate 200 includes but is not limited to at least one of the following materials: silicon (Si), germanium (Ge), silicon germanium (SiGe), silicon carbon (SiC), silicon germanium carbon (SiGeC), indium arsenide (InAs), gallium arsenide (GaAs), indium phosphide (InP) or other III / V compound semiconductors, or silicon on dielectric (SOI), stacked silicon on dielectric (SSOI), stacked silicon germanium on dielectric (S-SiGeOI), silicon germanium on dielectric (SiGeOI) and germanium on dielectric (GeOI).

[0043] Exemplarily, the substrate may also be a substrate after functional film layers and structures are formed on a semiconductor substrate, for example, a substrate after an interlayer dielectric layer is formed on a semiconductor substrate, that is, the substrate includes a semiconductor substrate and an interlayer dielectric layer, or the substrate may also be a substrate on which active devices or passive devices have been formed.

[0044] Next, step S120 is performed to form a first photoresist layer on the substrate.

[0045] like Figure 2B As shown, a first photoresist layer 201 is formed on a substrate 200. Exemplarily, the first photoresist layer is formed by spin coating and / or automatic spraying. Optionally, the first photoresist layer can be a negative photoresist layer or a positive photoresist layer, which can be reasonably set according to actual needs.

[0046] Next, step 130 is performed to process the first photoresist layer to form a second photoresist layer containing a graft copolymer.

[0047] Exemplarily, treating the first photoresist layer to form a second photoresist layer containing a graft copolymer includes: plasma treating the first photoresist layer to form free radicals in the first photoresist layer; coating a curing solution on the first photoresist layer after the plasma treatment to copolymerize the first photoresist layer with the curing solution to form a second photoresist layer containing a graft copolymer. In some embodiments, the plasma treatment can also be performed while the first photoresist layer is formed, or the plasma treatment can also be performed after the first photoresist layer of the bottom layer is formed, and then the plasma treatment is performed after the first photoresist layer is continuously coated to a predetermined thickness.

[0048] It is worth mentioning that the first photoresist layer may be completely transformed into the second photoresist layer containing the graft copolymer, or a part of the first photoresist layer may be transformed into the second photoresist layer containing the graft copolymer, which is not specifically limited here.

[0049] like Figure 2CAs shown, the first photoresist layer 201 is subjected to plasma treatment to form free radicals (not shown) in the first photoresist layer 201, and then, a curing solution 202 is coated on the first photoresist layer 201 after the plasma treatment. Exemplarily, the curing solution includes a solvent and an additive. The curing agent in the curing solution reacts chemically with the active groups in the copolymer to form a stable chemical bond, so that the copolymer is transformed from a liquid or viscous state to a solid state. Through curing, the physical and chemical properties of the copolymer are significantly improved, such as hardness, strength, heat resistance, and chemical corrosion resistance. At the same time, the components in the curing solution can affect the cross-linking density of the copolymer, The structural parameters such as the length of the molecular chain, thereby adjusting the performance of the copolymer. The solvent in the present application includes a curing agent and an auxiliary solvent, wherein the curing agent reacts with the active groups in the copolymer to achieve the curing of the copolymer. The selection of the curing agent depends on the type of the copolymer and the required curing conditions, and the auxiliary solvent plays a role in diluting, promoting the reaction, and transferring heat in the curing solution. The choice of solvent should take into account the compatibility with the copolymer, volatility and environmental impact; in order to improve the performance of the curing solution, some additives are usually added, such as catalysts, stabilizers, plasticizers, etc. These additives can accelerate the curing reaction, improve the stability of the cured product or adjust the performance of the cured product.

[0050] Exemplarily, the solvent includes at least one functional group selected from -X, -OH, -CHO, -NO2, -SO3H, -NH2, and RCO-. A functional group is a specific part of a molecule that can participate in a chemical reaction. X in -X represents a halogen atom, such as chlorine (Cl), fluorine (F), bromine (Br), iodine (I), etc. In organic compounds, the -X functional group is usually represented by a halogen atom replacing a hydrogen atom in a hydrocarbon molecule to form a halogenated hydrocarbon; -OH is the chemical formula of the hydroxyl functional group. The hydroxyl group is composed of an oxygen atom and a hydrogen atom. It is a common polar functional group. The hydroxyl group can exist in a variety of compounds, including alcohols, phenols, and carboxylic acids. The hydroxyl functional group can participate in a variety of chemical reactions, such as esterification, etherification, and oxidation reactions; -CHO is the chemical formula of the aldehyde functional group. The aldehyde group is composed of a carbon atom, an oxygen atom, and a hydrogen atom. It has special chemical properties. Aldehyde compounds usually have a pungent odor and are prone to addition. Reaction and oxidation reaction; -NO2 is the chemical formula of the nitro functional group. The nitro group is the group left after removing a hydroxyl group from the nitric acid molecule. It is composed of nitrogen atoms and oxygen atoms. The nitro group is usually connected to a hydrocarbon group or other groups to form a nitro compound. The nitro compound shows certain activity in chemical reactions and can participate in various types of reactions, such as reduction reactions, substitution reactions, etc. At the same time, the nitro group is also an important functional group in compounds such as dyes and drugs; -SO3H is the chemical formula of the sulfonic acid functional group. The sulfonic acid group has strong acidity. Sulfonic acid compounds are an important class of organic acids. Sulfonic acid functional groups are usually used to prepare compounds such as ion exchange resins, surfactants and dyes; -NH2 is the chemical formula of the amino functional group, which is a basic functional group; RCO- is the chemical formula of the acyl functional group (where R represents a hydrocarbon group). Acyl is a functional group derived from carboxylic acid. Acyl functional groups are widely used in organic synthesis and chemical reactions, such as esterification, amidation and acylation. Acyl is also an important functional group in compounds such as synthetic resins, coatings and drugs. The functional groups in the curing solution undergo copolymerization reaction with the free radicals in the first photoresist layer to form a graft copolymer.

[0051] like Figure 2C and Figure 2D As shown, the first photoresist layer 201 undergoes copolymerization reaction with the curing solution to form a second photoresist layer 203 containing a graft copolymer. Since the second photoresist layer 203 undergoes copolymerization reaction with the curing solution to form a graft copolymer, the adhesion of the second photoresist layer 203 is enhanced and its interface strength is also enhanced.

[0052] Usually, a copolymerization reaction occurs on the surface of the first photoresist layer to form a graft copolymer. In order to further enhance the adhesion of the second photoresist layer, photoresist coating, plasma treatment and curing solution coating can be performed multiple times to form a second photoresist layer. Therefore, in another embodiment, the following steps are repeated in sequence: forming a first photoresist layer on the substrate; treating the first photoresist layer to form a second photoresist layer containing a graft copolymer until the thickness of the second photoresist layer reaches a predetermined thickness. Optionally, the number of repeated cycles can be at least two times. It is worth mentioning that after the second photoresist layer of the first layer is formed, the first photoresist layer formed subsequently covers the second photoresist layer formed previously.

[0053] In a specific example, a first photoresist layer is processed to form a second photoresist layer containing a graft copolymer, including: a plasma treatment stage, in which the first photoresist layer is plasma treated to form free radicals in the first photoresist layer; a copolymerization reaction stage, in which a curing solution is coated on the first photoresist layer after the plasma treatment, so that the first photoresist layer and the curing solution undergo a copolymerization reaction to form a second photoresist layer containing a graft copolymer; a stage of forming the first photoresist layer again, in which if the thickness of the second photoresist layer is less than a predetermined thickness, the first photoresist layer is formed on the second photoresist layer; and the steps of the plasma treatment stage and the copolymerization reaction stage are sequentially performed, and the steps of forming the first photoresist layer, the plasma treatment stage, and the copolymerization reaction stage are repeated in sequence until the thickness of the second photoresist layer is not less than a predetermined thickness. In this embodiment, the first photoresist layer formed each time is a thin layer, that is, its thickness is less than the final predetermined thickness required. After each formation of the first photoresist layer, a copolymerization reaction is performed to form a second photoresist layer. Multiple layers of second photoresist layers are stacked together through multiple operations, so that the thickness of the final second photoresist layer meets the predetermined thickness. In this way, in the final second photoresist layer, not only the copolymerization reaction occurs on the surface to form a graft polymer, but also the graft polymer is formed inside the second photoresist layer, thereby further enhancing the adhesion of the second photoresist layer, which is more conducive to preventing the phenomenon of photoresist collapse.

[0054] Exemplarily, the plasma treatment adopts a low-temperature plasma treatment method. Low-temperature plasma treatment refers to the technology of using low-temperature plasma to modify, clean, etch, deposit and disinfect the surface of materials. Low-temperature plasma is a plasma in non-thermodynamic equilibrium, and its electrons have high energy, which can break the chemical bonds of molecules on the surface of the material and increase the chemical reactivity of the particles. Low-temperature plasma treatment involves the surface of the material and does not change the overall properties of the matrix. The reaction system of low-temperature plasma treatment can be maintained in a low-temperature environment. Exemplarily, the ambient temperature range of the reaction system of low-temperature plasma treatment can be 10°C-30°C.

[0055] The process of low-temperature plasma treatment includes pretreatment, low-temperature plasma generation, plasma reaction and post-treatment. The main purpose of pretreatment is to remove large-area contaminants and loose impurities on the surface of the material so that the subsequent plasma treatment can be carried out more effectively. Low-temperature plasma generation is usually achieved by ionizing gas, that is, using electric field or high-energy radiation to ionize gas molecules or atoms to form plasma composed of active particles such as electrons, ions, free radicals, etc. These active particles have high energy and high activity, and can react chemically or physically with the surface of the material to achieve cleaning, modification, etching and other effects. In the plasma reaction stage, the generated low-temperature plasma interacts with the surface of the treatment object. These interactions may include chemical reactions (such as oxidation, reduction, decomposition, etc.) and physical effects (such as bombardment, etching, etc.). These effects can remove contaminants on the surface of the material, change the surface properties, form new chemical bonds, etc. After the low-temperature plasma treatment is completed, post-treatment is usually required to ensure the treatment effect. Post-treatment may include steps such as purging with pure gas, drying, high-temperature roasting, etc. to remove residual plasma active particles, organic matter or other contaminants, and consolidate the treatment effect.

[0056] Exemplarily, the plasma treatment adopts at least one of the following treatment methods: corona discharge plasma treatment, glow discharge plasma treatment, spark discharge plasma treatment, dielectric barrier discharge plasma treatment, sliding arc discharge plasma treatment, microwave plasma treatment and radio frequency plasma treatment. Exemplarily, the electron temperature range of the plasma treatment is 0K-10 4 K, of which 10 4 K is approximately equal to 1eV (electron volt).

[0057] Exemplarily, when the plasma treatment adopts glow discharge plasma treatment and / or radio frequency plasma treatment, the gas temperature range of the glow discharge plasma treatment is 0K-500K, and the gas temperature range of the radio frequency plasma treatment is 0K-500K.

[0058] Exemplarily, when the plasma treatment adopts corona discharge plasma treatment and / or microwave plasma treatment, the gas temperature range of the corona discharge plasma treatment is 0K-300K, and the gas temperature range of the microwave plasma treatment is 0K-800K.

[0059] Specifically, when the plasma treatment is glow discharge plasma treatment, such as DC glow discharge plasma treatment, the electron density is in the range of 10 9 -10 12 The number of electrons / cubic centimeter, the electric field strength ranges from 40-6*10 4V / cm, pressure <100 Torr, 1 Torr is equal to the pressure generated by 1 mm of mercury, which is also equal to 1 / 760 of standard atmospheric pressure, and the electron temperature ranges from 0K to 10 4 K, the gas temperature ranges from 0K to 500K; when the plasma treatment adopts radio frequency plasma treatment, such as high frequency plasma treatment, the electron density ranges from 10 8 -10 10 The number of electrons / cubic centimeter, the electric field strength ranges from 100-600 V / cm, the pressure is <100 Torr, and the electron temperature ranges from 0 K to 10 4 K, the gas temperature ranges from 0K to 500K; when microwave plasma treatment is used, the electron density ranges from 10 10 -10 11 The number of electrons / cubic centimeter, the pressure is <100 Torr, and the electron temperature ranges from 0K to 10 4 K, the gas temperature range is 0K-800K; when the plasma treatment adopts corona discharge plasma treatment, the electron density range is 10 3 -10 6 The number of electrons / cubic centimeter, the range of electric field strength is 2*10 4 -1*10 6 V / cm, pressure <100 Torr, electron temperature range 0K-10 4 K, the gas temperature ranges from 0K to 300K.

[0060] The plasma treatment is carried out by adopting a low-temperature plasma treatment method so that the electrons have high enough energy to excite, dissociate and ionize the reactant molecules, and at the same time the plasma treated reaction system can be kept running in a low-temperature environment.

[0061] Exemplarily, the method for preparing a photoresist layer further includes: covering the second photoresist layer with a mask; exposing the second photoresist layer through the mask; and developing the second photoresist layer to form a patterned photoresist layer. Figure 2E As shown, a mask 204 containing a predetermined pattern is selected, and the mask 204 is placed on the second photoresist layer 203. The second photoresist layer 203 is exposed through the mask 204. Specifically, the pattern on the mask 204 is projected onto the second photoresist layer 203 through an optical system by light, so as to achieve pattern transfer. Exemplarily, the exposure method includes contact exposure, proximity exposure and projection exposure. Then, as shown in FIG. Figure 2FAs shown, the developer is used for development, and the exposed area of ​​the positive photoresist and the non-exposed area of ​​the negative photoresist are dissolved in the development, presenting a three-dimensional pattern in the second photoresist layer 203, thereby forming a patterned photoresist layer 205. At this point, the photoresist layer is prepared, and in the subsequent semiconductor process, the patterned photoresist layer is used as a mask to etch the material under the patterned photoresist layer for subsequent steps.

[0062] So far, the process steps of the method for preparing a photoresist layer according to an embodiment of the present invention have been completed. It can be understood that the method for preparing a photoresist layer in this embodiment not only includes the above steps, but also may include other necessary steps before, during or after the above steps, which are all included in the scope of the manufacturing method of this embodiment. It is worth mentioning that the method for preparing a photoresist layer can be a step in a method for preparing a semiconductor device, which can be used for the preparation of any suitable semiconductor device, and is not specifically limited here.

[0063] The method for preparing a photoresist layer provided by the present invention forms a second photoresist layer containing a graft copolymer by processing the first photoresist layer after the first photoresist layer is formed. Since the second photoresist layer contains the graft copolymer, the adhesion of the second photoresist layer and the interface strength of the photoresist layer are improved, thereby reducing the risk of collapse of the second photoresist layer and improving the reliability of device quality.

[0064] It should be noted that the above embodiments illustrate the present application rather than limit the present application, and that those skilled in the art may design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets should not be constructed as a limitation on the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "one" or "an" preceding an element does not exclude the presence of multiple such elements. The present application may be implemented with the aid of hardware including several different elements and with the aid of appropriately programmed computers. In a unit claim listing several on-board systems, several of these on-board systems may be embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order. These words may be interpreted as names.

[0065] The above is only a specific implementation method or description of a specific implementation method of the present application, and the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. The protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for preparing a photoresist layer, characterized in that: include: providing a substrate; forming a first photoresist layer on the substrate; treating the first photoresist layer to form a second photoresist layer containing a graft copolymer; covering the second photoresist layer with a mask; exposing the second photoresist layer through the mask; developing the second photoresist layer to form a patterned photoresist layer; The step of processing the first photoresist layer to form a second photoresist layer containing a graft copolymer comprises: performing plasma treatment on the first photoresist layer to form free radicals in the first photoresist layer; A curing solution is coated on the first photoresist layer after the plasma treatment, so that the first photoresist layer and the curing solution undergo copolymerization reaction to form a second photoresist layer containing a graft copolymer.

2. The preparation method according to claim 1, characterized in that The preparation method further comprises: The following steps are repeatedly performed in sequence: forming a first photoresist layer on the substrate; and processing the first photoresist layer to form a second photoresist layer containing a graft copolymer until the thickness of the second photoresist layer reaches a predetermined thickness.

3. The preparation method according to claim 1, characterized in that: The plasma treatment adopts at least one of the following treatment methods: corona discharge plasma treatment, glow discharge plasma treatment, spark discharge plasma treatment, dielectric barrier discharge plasma treatment, sliding arc discharge plasma treatment, microwave plasma treatment and radio frequency plasma treatment.

4. The preparation method according to claim 1, characterized in that: The electron temperature range of the plasma treatment is 0K-10 4 K.

5. The preparation method according to claim 3, characterized in that: When the plasma treatment adopts glow discharge plasma treatment and / or radio frequency plasma treatment, the gas temperature range of the glow discharge plasma treatment is 0K-500K, and the gas temperature range of the radio frequency plasma treatment is 0K-500K.

6. The preparation method according to claim 3, characterized in that: When the plasma treatment adopts corona discharge plasma treatment and / or microwave plasma treatment, the gas temperature range of the corona discharge plasma treatment is 0K-300K, and the gas temperature range of the microwave plasma treatment is 0K-800K.

7. The preparation method according to claim 1, characterized in that: The curing solution includes a solvent and an additive.

8. The preparation method according to claim 7, characterized in that: The solvent includes at least one functional group selected from -X, -OH, -CHO, -NO2, -SO3H, -NH2, and RCO-.

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