Compounds, polymers, photoresist compositions, and pattern forming methods

Abstract

The application discloses a compound, a polymer, a photoresist composition and a pattern forming method, and the structure of the compound is shown in formula (1). In formula (1), R1 is a methyl group, a trifluoromethyl group or a hydrogen atom, R2 is a substituted or unsubstituted saturated cycloalkyl group with a carbon number of 4-12, R3 is a group containing an epoxy functional group, the epoxy functional group is arranged at a molecular end, and m is an arbitrary integer between 1 and 3. The photoresist composition of the application can limit the acid diffusion range, effectively reduce the line width roughness and size deviation, and greatly improve the pattern edge definition due to containing the polymer with the compound structural unit shown in formula (1). Relying on the polarity inversion and crosslinking double curing mechanism, the solvent resistance of the exposed area is stronger, the low exposure dose can be formed, the high sensitivity and high resolution are considered, the overall molecular structure stability is strong, the adaptability to parameters such as exposure amount, focal length and baking temperature is good, and therefore, the wider exposure tolerance and focal depth are obtained.

Description

Technical Field

[0001] This invention relates to the field of microfabrication technology in semiconductor manufacturing, specifically to a compound, polymer, resist composition, and patterning method. Background Technology

[0002] As the feature size of semiconductor devices continues to shrink to the deep submicron and nanometer scale, photolithography, as a core patterning process in semiconductor manufacturing, faces unprecedented precision and performance requirements. Its resolution, linewidth roughness, and process window directly determine the integration density and reliability of semiconductor devices. In advanced processes, negative lithography, especially negative lithography using organic solvents as developers, has gradually replaced traditional positive lithography, becoming one of the key core technologies in advanced semiconductor manufacturing, due to its superior process window, higher resolution, and better pattern fidelity in the formation of key patterns such as contact holes and trenches.

[0003] In negative lithography using organic solvent development, the core working principle is as follows: the photoresist components in the exposed area undergo a specific chemical reaction under the photo-induced acid catalysis, causing a sharp decrease in the solubility of the photoresist in the organic solvent developer, thus retaining it. Meanwhile, the photoresist components in the unexposed area maintain a higher solubility in the organic solvent and are dissolved and removed during development, ultimately forming a negative pattern that meets the design requirements. Therefore, achieving a high "dissolution contrast" between the exposed and unexposed areas—that is, a significant difference in their solubility in the organic solvent—is crucial for improving lithographic pattern resolution, reducing linewidth roughness, and ensuring critical dimension uniformity. It is also a core technical challenge in the current development of negative photoresists.

[0004] Currently, the mainstream negative photoresists used in advanced processes are all chemically amplified types. These photoresists are typically prepared by a multi-component physical mixing method. Their core components mainly include a matrix resin, a photoacid generator (PAG), and a quencher. Each component has a clear functional division: the matrix resin serves as the main framework of the photoresist, and its molecular structure contains acid-instable groups (such as acetal groups and ester groups). These groups can undergo decomposition reactions under the catalysis of acid, releasing polar groups such as hydroxyl and carboxyl groups, thereby significantly reducing the solubility of the matrix resin in organic solvents and achieving the preservation of the exposure area; the photoacid generator is a small molecule compound that can absorb photons and decompose during photolithography exposure, producing strong acids (such as sulfonic acids), providing catalytic conditions for the decomposition reaction of acid-instable groups in the matrix resin; the quencher is mainly used to capture excess acid in the system or inhibit the random diffusion of acid, avoiding problems such as photolithography pattern distortion and linewidth deviation caused by excessive acid diffusion.

[0005] However, the aforementioned multi-component physical mixing preparation mode has inherent defects that are difficult to overcome, severely restricting the application effect of chemically amplified negative photoresists in advanced processes. Specifically, these defects are as follows: First, the component distribution is uneven. Both the photoacid generator and the quencher are small molecule compounds, which are prone to microphase separation or local aggregation in the matrix resin. This results in spatial non-uniformity of acid generation and acid-catalyzed reactions after exposure, directly degrading the linewidth roughness and critical size uniformity of the photolithographic pattern, and affecting the performance stability of semiconductor devices. Second, acid diffusion is difficult to control. The free small molecule acids generated by the decomposition of the photoacid generator are prone to random diffusion, making it difficult to control through the quencher. Achieving precise constraints can easily lead to defects such as lithographic pattern expansion, bridging, and dimensional drift, further reducing pattern fidelity. Third, the poor synergy among components means that the matrix resin, photoacid generator, and quencher respond independently to lithography process conditions (such as exposure dose and baking temperature), lacking effective molecular-level synergy. This makes it difficult to simultaneously widen key process windows such as exposure tolerance and depth of focus, increasing the difficulty of process control. Fourth, the complex formulation system and the coexistence of multiple components not only increase the compatibility requirements between components but also easily lead to stability problems such as layering and precipitation during photoresist storage, increasing production, storage, and usage costs.

[0006] In summary, the aforementioned defects in existing chemically amplified negative photoresists, which employ a multi-component physical mixing mode, have become a key bottleneck restricting their adaptation to further miniaturization of semiconductor device features and their ability to meet the requirements of advanced photolithography processes. Therefore, there is an urgent need in this field to develop a novel photoresist material that integrates core functions such as acid generation, acid control, and solubility conversion at the molecular scale. This would fundamentally solve the numerous problems caused by multi-component physical mixing and meet the stringent requirements of advanced semiconductor photolithography processes for resolution, linewidth roughness, and process stability. Summary of the Invention

[0007] The purpose of this invention is to solve the above-mentioned problems and provide a compound that integrates a photoacid generation unit and an acid-responsive solubility conversion unit through chemical bonds. The polymer prepared from this compound can achieve intramolecular synergy of acid generation, diffusion and resin polarity reversal, thereby providing a photoresist composition suitable for organic solvent development, with ultra-high solubility contrast and excellent pattern accuracy.

[0008] To achieve these objects and other advantages of the present invention, a first aspect of the present invention provides a compound represented by general formula (1), the structure of which is shown below:

[0009] In formula (1), R1 is methyl, trifluoromethyl or hydrogen atom, R2 is substituted or unsubstituted saturated cycloalkyl group with 4 to 12 carbon atoms, R3 is a group containing epoxy functional group, wherein the epoxy functional group is located at the end of the molecule, and m is any integer between 1 and 3.

[0010] A second aspect of the present invention provides a polymer comprising the structural units of the compound shown in formula (1) above.

[0011] The saturated cycloalkyl group is selected from at least one of the following structures: Preferred .

[0012] Wherein, the epoxy-functionalized group is selected from at least one of the following structures: Preferred .

[0013] Furthermore, in equation (1), m is preferably 1.

[0014] Furthermore, the content of the structural units of the compound shown in formula (1) is 1-15 mol%, more preferably 3-10 mol%.

[0015] A third aspect of the present invention provides a photoresist composition comprising: the polymer (A) described above, an acid diffusion control agent (B), a fluorinated resin (C), and an organic solvent (D).

[0016] Furthermore, the polymer (A) also comprises structural units with acid-dissociable groups as shown in formula (A-1) and structural units with lactone groups as shown in formula (A-2): ,

[0017] In formulas (A-1) and (A-2), R4 independently represents a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; R5 represents an acid-unstable group; R6 represents a hydrocarbon group with 1 to 10 carbon atoms; X represents an oxygen atom, an ester group, a carbonate group, or an imino group; R7 represents a monovalent organic group containing a lactone structure; and n is any integer between 0 and 10.

[0018] Preferably, the polymer (A) is a quaternary or pentagonal copolymer.

[0019] A fourth aspect of the present invention provides a pattern forming method, comprising the following steps: (1) A photoresist film is formed on a substrate using the photoresist composition described above; (2) Expose the above-mentioned resist film; (3) After baking, the exposed resist film is developed with a developer to obtain a photoresist pattern.

[0020] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a compound comprising a polymer synthesized from the compound and a photoresist composition, wherein the intramolecular acid production is uniformly distributed, which can limit the acid diffusion range, effectively reduce line width roughness and dimensional deviation, and significantly improve the clarity of pattern edges; relying on the dual curing mechanism of polarity reversal and cross-linking, the exposed area has stronger solvent resistance, and low exposure dose can be used for molding, taking into account both high sensitivity and high resolution; the overall molecular structure has strong stability and good adaptability to parameters such as exposure amount, focal length, and baking temperature, thereby obtaining a wider exposure latitude and depth of focus.

[0021] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Detailed Implementation

[0023] Before the following detailed description of the invention, it should be understood that the terminology used in this invention is for describing particular embodiments only. Unless otherwise stated, all technical and scientific terms used in this invention have the same meaning as commonly understood by those skilled in the art.

[0024] Furthermore, the terms or words used in this specification are intended to be understood based on the principle that the inventors may appropriately define the concepts of the terms in order to best describe the invention, and are not limited to the conventional meanings.

[0025] <Compound>

[0026] This invention provides a compound with the structure shown in formula (1):

[0027] In formula (1), R1 is methyl, trifluoromethyl, or hydrogen atom, R2 is a substituted or unsubstituted saturated cycloalkyl group with 4 to 12 carbon atoms, R3 is a group containing an epoxy functional group located at the end of the molecule, and m is any integer between 1 and 3. R3 also contains an aromatic group.

[0028] For ease of understanding, examples of saturated cycloalkyl groups are given by way of example, but the invention is not limited thereto.

[0029]

[0030] The saturated cycloalkyl group in the embodiments of the present invention is preferably adamantyl alkyl: .

[0031] For ease of understanding, examples of groups containing epoxy functional groups are given by way of example, but are not limited thereto.

[0032]

[0033] The epoxy-functionalized groups described in the embodiments of the present invention are preferably those containing epoxy functional groups. .

[0034] The present invention also provides a method for preparing the compound, and the synthetic route is not limited. Exemplary synthetic routes are listed below:

[0035] .

[0036] In the above synthetic route, step 1 is a copper-catalyzed Ullmann-type CS cross-coupling reaction, using 4-hydroxyphenylthiophenol as a sulfur nucleophile and R3-Br as an electrophile to construct a thioether intermediate under the synergistic effect of copper catalyst, ligand, and base. During the reaction, both the phenolic hydroxyl group and the epoxy group remain stable. Step 2 is a selective oxidation reaction of the thioether, where the 4-hydroxyphenyl thioether intermediate obtained in step 1 is selectively oxidized to the corresponding sulfoxide compound under mild oxidation conditions. During the reaction, the functional groups such as the phenolic hydroxyl group and the epoxy and benzene rings in the R3 group are not destroyed, resulting in a high yield of 4-hydroxyphenyl. Step 3 is the Wildi reaction, in which the 4-hydroxyaryl sulfoxide intermediate obtained in step 2 is reacted with magnesium p-fluorophenyl bromide (aryl Grignard reagent) to construct a triaryl sulfonium salt skeleton, generating an aryl p-fluorophenyl sulfonium bromide containing phenolic hydroxyl groups. This reaction uses sulfoxide as the sulfur source and aryl Grignard reagent as the nucleophile, forming a CS bond and constructing a positively charged sulfonium center in one step. Step 4 is the esterification reaction of phenolic hydroxyl groups, in which the sulfonium salt intermediate containing phenolic hydroxyl groups obtained in step 3 is reacted with methacryloyl chloride to introduce methacrylate groups onto the phenolic hydroxyl groups, constructing a sulfonium salt type methacrylate monomer.

[0037] Step 5 involves the benzyl protection reaction of alicyclic hydroxyl groups, such as the benzyl protection reaction of the hydroxyl group in 4-hydroxycyclohexylacetic acid. Using potassium carbonate as a base, a nucleophilic substitution reaction occurs with the benzylating reagent in an organic solvent. The alicyclic hydroxyl group is deprotonated to form an alkoxide anion, which attacks the benzyl carbon at the benzyl position of the bromide, removing the bromide ion and converting the hydroxyl group into a benzyl ether structure. Step 6 involves the acyl chloride followed by thioesterification of the carboxylic acid. First, oxaloyl chloride is used to convert the carboxylic acid into a highly reactive acyl chloride intermediate. Then, sodium methanethiolate is prepared from sodium sulfide and iodomethane, and the two undergo a nucleophilic acyl substitution reaction, converting the carboxylic acid group into a benzyl ether structure. Step 7 involves the deoxydifluorination of the dithiocarboxylic acid S-methyl ester, using DAST or Deoxo-Fluor as the fluorinating agent to convert the thiocarbonyl group (C=S) in the substrate to a difluoromethylene group (CF2), yielding the target product containing an α,α-difluorosulfide structure. Step 8 is the selective oxidation of the sulfide, using m-chloroperoxybenzoic acid (m-CPBA) or sodium periodate as the oxidant to selectively oxidize the methylthio group (-SMe) in the substrate to a methyl sulfoxide group. (-S(=O)Me); Step 9 is the Julia-Kocienski olefination reaction, in which the intermediate containing α,α-difluoromethyl sulfoxide is treated with a base, and methyl sulfinate is removed by a cis-elimination reaction to form a carbon-carbon double bond, yielding the target product containing a 1,1-difluoroolefin structure; Step 10 is the free radical addition sulfonation reaction of 1,1-difluoroolefin, using sodium bisulfite as the sulfonating agent. Under the action of an initiator, 1,1-difluoroolefin undergoes an addition reaction with sulfonyl free radicals, the double bond is reduced and a sodium sulfonate group is introduced, yielding α,α - Sodium difluoroalkyl sulfonate product; Step 11 is the removal reaction of the benzyl protecting group, using palladium on carbon as a catalyst, the intermediate containing the benzyl ether structure is catalytically hydrogenated under a hydrogen atmosphere, the CO bond is broken, the benzyl group is removed, and the target product containing the alcohol hydroxyl group is obtained; Step 12 is the etherification and anion exchange reaction of the triaryl sulfonate salt, using the sodium fluorosulfonate intermediate containing the alcohol hydroxyl group and the triaryl sulfonate bromide salt as raw materials, a substitution reaction occurs under the action of alkali, and at the same time the counterion of the triaryl sulfonate cation is exchanged from the bromide salt to the fluoroalkyl sulfonate anion, to obtain the triaryl sulfonate fluoroalkyl sulfonate product.

[0038] The definitions of R1, R2, R3, and m are the same as above.

[0039] <Polymer>

[0040] The present invention provides a polymer comprising the structural unit of the compound shown in formula (1).

[0041] In this invention, the lower limit of the content of the structural unit shown in formula (1) is preferably 1 mol%, more preferably 3 mol%; the upper limit of the content of the structural unit shown in formula (1) is preferably 25 mol%, more preferably 15 mol%, and particularly preferably 10 mol%. By setting the content of the structural unit shown in formula (1) within the range, the resolution and CDU performance of the photoresist composition can be further improved.

[0042] In this embodiment of the invention, the polymer further comprises a structural unit having an acid-dissociable group (Formula A-1) and a structural unit having a lactone skeleton (Formula A-2).

[0043]

[0044] In formulas (A-1) and (A-2), R4 independently represents a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; R5 represents an acid-unstable group; R6 represents a hydrocarbon group with 1 to 10 carbon atoms; X represents an oxygen atom, an ester group, a carbonate group, or an imino group; R7 represents a monovalent organic group containing a lactone structure; and n is any integer between 0 and 10.

[0045] For ease of understanding, examples of acid-labile groups R5 are provided as examples, but the invention is not limited thereto.

[0046]

[0047] .

[0048] For ease of understanding, examples of formula (A-1) are given by way of example, but the invention is not limited thereto.

[0049]

[0050] In this invention, among all the structural units constituting the polymer, the lower limit of the content of structural unit (A-1) is preferably 20 mol%, more preferably 25 mol%, and the upper limit of the content of structural unit (A-1) is preferably 90 mol%, more preferably 75 mol%, and particularly preferably 55 mol%. By setting the content of structural unit (A-1) within the aforementioned range, the sensitivity and CDU performance of the photoresist composition can be further improved.

[0051] For ease of understanding, examples of formula (A-2) are given by way of example, but the invention is not limited thereto.

[0052]

[0053] In this invention, the polymer, by including structural unit (A-2), can adjust its solubility in the developer to a suitable level, thereby further improving the sensitivity and CDU performance of the photoresist composition. Additionally, it can improve the adhesion between the film formed from the photoresist composition and the substrate.

[0054] In this invention, among all the structural units constituting the polymer, the lower limit of the content of structural unit (A-2) is preferably 10 mol%, more preferably 20 mol%; the upper limit of the content of structural unit (A-2) is preferably 80 mol%, more preferably 50 mol%. By setting the content ratio of structural unit (A-2) within the aforementioned range, the sensitivity and CDU performance of the photoresist composition can be further improved.

[0055] In this embodiment of the invention, the polymer is preferably a quaternary or pentadienyl copolymer resin.

[0056] Polymer Synthesis Methods Polymers can be synthesized, for example, by polymerizing monomers that provide the structural units in a suitable solvent in the presence of a free radical polymerization initiator or the like.

[0057] The free radical polymerization initiator comprises one or more combinations of azo-based free radical initiators and peroxide-based free radical initiators, preferably one or more combinations of 2,2'-azobis(2-methylpropionic acid)dimethyl ester, azobisisobutyronitrile, and 2,2'-azobisisobutyratedimethyl ester.

[0058] Examples of solvents used as solvents in the polymerization process include: straight-chain alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane; cycloalkanes such as cyclohexane, cycloheptane, and cyclooctane; aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; halogenated hydrocarbons such as chlorobutane, bromohexane, dichloroethane, hexamethylenedibromo, and chlorobenzene; saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, isobutyl acetate, and methyl propionate; ketones such as acetone, 2-butanone, 4-methyl-2-pentanone, and 2-heptanone; ethers such as tetrahydrofuran, dimethoxyethane, and diethoxyethane; and alcohols such as methanol, ethanol, 1-propanol, 2-propanol, and 4-methyl-2-pentanol. These solvents can be used individually or in combination of two or more.

[0059] The polymerization temperature is preferably 40℃~150℃, and more preferably 50℃~120℃. The reaction time is preferably 1h~48h, and more preferably 1h~24h.

[0060] The weight-average molecular weight (Mw) of the polymer, converted to polystyrene by gel permeation chromatography (GPC), is preferably 5,000 to 30,000. If Mw is less than 5,000, it may be impossible to obtain a photoresist film with a sufficient receding contact angle. On the other hand, when Mw exceeds 30,000, the developability of the photoresist film may deteriorate.

[0061] The ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn) of polystyrene as determined by GPC, Mw / Mn, is preferably 1 to 4, and more preferably 1 to 3.

[0062] <Photoresist Composition>

[0063] The present invention provides a photoresist composition comprising: the polymer (A) described above, an acid diffusion control agent (B), a fluorinated resin (C), and a solvent (D).

[0064] Acid diffusion control agent (B)

[0065] The photoresist composition of the present invention may further include, as needed, an acid diffusion control agent, which includes a nitrogen-containing compound or a compound represented by the following formula (3).

[0066] The nitrogen-containing compounds include one or more combinations of amide-containing compounds, urea compounds, and nitrogen-containing heterocyclic compounds. Specific examples of the nitrogen-containing compounds include: di-n-butylamine, triethylamine, aniline, 2,6-diisopropylaniline, ethylenediamine, N,N,N',N'-tetramethylethylenediamine, polyethyleneimine, polyallylamine, dimethylaminoethylacrylamide, formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone, urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1 Pyridine derivatives such as 3-diphenylurea, tributylthiourea, pyridine, and 2-methylpyridine; N-propylmorpholine, N-(undecylcarbonyloxyethyl)morpholine, pyrazine, pyrazole, benzimidazole, 2-phenylbenzimidazole, N-tert-butoxycarbonylpiperidine, N-tert-butoxycarbonylimidazolium, N-tert-butoxycarbonylbenzimidazole, N-tert-butoxycarbonyl-2-phenylbenzimidazole, N-(tert-butoxycarbonyl)di-n-octylamine, N-(tert-butoxycarbonyl)diethanolamine, N-(tert-butoxycarbonyl)dicyclohexylamine, N-(tert-butoxycarbonyl)diphenylamine, N-tert-butoxycarbonyl-4-hydroxypiperidine, and N-tert-pentoxycarbonyl-4-hydroxypiperidine, etc.

[0067] R8-SO3 - M + Equation (3)

[0068] In formula (3), R8 represents one or more combinations of alkyl, alicyclic hydrocarbon or aryl groups with 1 to 20 carbon atoms, whether substituted or unsubstituted, and M + It represents a thionium salt cation, preferably a thionium cation.

[0069] Equation (3) can be listed as follows: .

[0070] The amount of acid diffusion control agent added according to the present invention is preferably 20 parts by mass or less and 0.01 parts by mass or more relative to 100 parts by mass of polymer (A). When the amount of acid diffusion control agent added exceeds 20 parts by mass, the sensitivity of the formed photoresist film tends to decrease significantly.

[0071] Fluorinated resin (C)

[0072] In the resist composition of the present invention, a fluorinated resin (C) different from the main resin (A) may be contained. After the fluorinated resin (C) is spin-coated into a film, it tends to separate on the photoresist surface. Due to the presence of the fluorinated resin, water and water-soluble components are not easily leached out from the resist film formed by the resist composition. Therefore, the resist composition containing the fluorinated resin can play a good role in protecting the exposure lens of the lithography machine.

[0073] In this embodiment of the invention, the fluorinated resin comprises at least one repeating unit selected from formulas (e) and (f): , .

[0074] Where R independently represents a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; L G It is an acid-labile group; for details, please refer to the aforementioned content regarding formula (A-1) of this invention. f5 This refers to fluorinated hydrocarbons with 1 to 30 carbon atoms.

[0075] For ease of understanding, as an example, the present invention provides formula R. f5 Examples, but not limited to, are given.

[0076] .

[0077] The synthesis method of fluorinated resin (C) can be appropriately applied to the manufacturing method of polymer (A).

[0078] The Mw of the polystyrene-converted fluorinated resin (C), as determined by GPC, is preferably 1000 to 50000, more preferably 1000 to 40000, and particularly preferably 1000 to 30000. If Mw is less than 1000, it may be impossible to obtain a photoresist film with a sufficient receding contact angle. On the other hand, when Mw exceeds 50000, the developability of the photoresist film may deteriorate. The Mw / Mn ratio of the fluorinated resin (C) is preferably 1 to 5, more preferably 1 to 4.

[0079] The amount of fluorinated resin added needs to be precisely balanced between hydrophobic isolation and development compatibility: too low a concentration leads to uncontrolled dissolution and defects, while too high a concentration results in phase separation and development residue. Contact angle testing, development rate analysis, and defect detection optimization ensure that the photoresist exhibits high hydrophobicity, high developability, and high pattern quality during the immersion process. The lower limit of the fluorinated resin (C) content relative to 100 parts by weight of polymer (A) is preferably 0.1 parts by weight, more preferably 0.5 parts by weight, more preferably 1 part by weight, and particularly preferably 2 parts by weight; the upper limit of the fluorinated resin (C) content is preferably 30 parts by weight, more preferably 20 parts by weight, more preferably 15 parts by weight, and particularly preferably 10 parts by weight.

[0080] (D) Solvent

[0081] The organic solvent in the photoresist composition of this invention is not particularly limited, as long as it can dissolve other components. Examples of solvents include ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, propylene glycol monotert-butyl ether acetate, and γ-butyrolactone; and ketone solvents such as cyclohexanone. These solvents can be used alone or in combination of two or more. Preferably, the solvent is one or more combinations of PGMEA, cyclohexanone, and γ-butyrolactone.

[0082] The amount of organic solvent added is 500 to 5000 parts by weight relative to 100 parts by weight of the base resin, preferably 100 to 4000 parts by weight.

[0083] (E) Any other components

[0084] The resist composition may contain any other components besides those listed in (A) to (D) above. Examples of other arbitrary components (E) include other acid-generating agents, surfactants, compounds containing alicyclic skeletons, sensitizers, etc. These other arbitrary components may be used individually or in combination of two or more.

[0085] <Preparation Method of Resist Composition>

[0086] This photoresist composition can be prepared, for example, by mixing (A) a base resin, (B) an acid diffusion inhibitor, (C) a fluorinated resin, and (D) a solvent in a prescribed ratio, and preferably by filtering the resulting mixture through a filter with a pore size of approximately 0.2 μm. The lower limit of the solid component concentration in this photoresist composition is preferably 0.1% by mass, more preferably 0.5% by mass. The upper limit of the above solid component concentration is preferably 30% by mass, and more preferably 20% by mass.

[0087] This resist composition can be used for negative patterning with a developer containing organic solvents to achieve higher resolution.

[0088] <Pattern Formation Methods>

[0089] This invention provides a pattern forming method. When forming a photolithographic pattern using the resist composition of this invention, the following steps are generally performed: (1) A photoresist film is formed on a substrate using the photoresist composition provided by the present invention; (2) After drying, the resist film is exposed to the light; (3) After baking, the exposed resist film is developed with a developer to obtain a photoresist pattern.

[0090] In step (1), the solution of the composition is coated onto a substrate such as a silicon wafer or an aluminized wafer by an appropriate coating method such as spin coating, casting coating, or roll coating to form a photoresist film. Specifically, after coating the photoresist composition solution to a specified thickness, the photoresist film is pre-baked to evaporate the solvent in the coating and form the photoresist film.

[0091] The thickness of the resist film is preferably 10 nm to 5000 nm, and more preferably 10 nm to 2000 nm.

[0092] The pre-baking heating conditions vary depending on the composition of the photoresist composition, and are preferably around 30°C to 200°C, and more preferably 50°C to 150°C.

[0093] In step (2), the resist film obtained by the above coating is exposed. This exposure is performed by irradiating radiation through a mask with a predetermined pattern, in the presence of an immersion exposure solution such as water.

[0094] As an immersion exposure solution, a liquid with a refractive index greater than that of air is typically used. Specifically, examples include pure water, long-chain or cyclic aliphatic compounds, etc. With the immersion exposure solution in between—that is, with the space between the lens and the resist film filled with the immersion exposure solution—radiation is irradiated from the exposure apparatus, and the resist film is exposed through a mask with a predetermined pattern.

[0095] As for the aforementioned radiation, depending on the type of radiation-sensitive acid-generating agent used, it can be appropriately selected from visible light, ultraviolet light, far-ultraviolet light such as ArF excimer laser (wavelength 193nm), KrF excimer laser (wavelength 248nm), ultraviolet light (EUV, 13.5nm), electromagnetic waves such as X-rays, electron beams, charged particle beams such as alpha rays, etc., among which ArF excimer laser, KrF excimer laser, EUV, X-rays and electron beams are preferred, and ArF excimer laser, EUV and electron beams are more preferred. It should be noted that the exposure amount and other exposure conditions can be appropriately selected according to the formulation of the radiation-sensitive resin composition, the type of additives, etc.

[0096] Preferably, the exposed photoresist film is subjected to heat treatment (hereinafter also referred to as "post-exposure heating (post-exposure baking, PEB)"). This PEB allows for the smooth dissociation reaction of acid-dissociable groups in the polymer (A), etc. The heating conditions of the PEB can be appropriately adjusted according to the formulation of the photoresist composition. The lower limit of the PEB temperature is preferably 30°C, more preferably 50°C, and even more preferably 70°C. The upper limit of the above temperature is preferably 200°C, more preferably 150°C, and even more preferably 120°C. The lower limit of the PEB time is preferably 10 seconds, more preferably 30 seconds. The upper limit of the above time is preferably 600 seconds, more preferably 300 seconds.

[0097] In step (3), the resist film exposed by the above exposure process is developed. Examples of organic solvent developers include hydrocarbon solvents, ether solvents, ester solvents, ketone solvents, alcohol solvents, and other organic solvents, or liquids containing organic solvents. Examples of organic solvents include one or more solvents exemplified as solvents in the above-described resist composition. Ester solvents and ketone solvents are preferred. As an ester solvent, an acetate solvent is preferred, more preferably n-butyl acetate. As a ketone solvent, a chain ketone is preferred, more preferably 2-heptanone. The lower limit of the organic solvent content in the organic solvent developer is preferably 80% by mass, more preferably 90% by mass, further preferably 95% by mass, and particularly preferably 99% by mass. These developers can be used alone or in combination of two or more.

[0098] At the end of development, the resist film is rinsed. The rinsing solution is preferably a solvent that mixes with the developer but does not dissolve the resist film. Suitable solvents include alcohols with 3 to 10 carbon atoms, ether compounds with 8 to 12 carbon atoms, alkanes, alkenes, and alkynes with 6 to 12 carbon atoms, as well as aromatic solvents. Specifically, suitable alkanes with 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, and cyclononane. Suitable alkenes with 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, and cyclooctene. Suitable alkynes with 6 to 12 carbon atoms include hexyne, heptyne, and octyne. Suitable alcohols with 3 to 10 carbon atoms include n-propanol, isopropanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentanol, neopentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, and 1-octanol. Suitable ether compounds having 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, di-sec-butyl ether, di-n-pentyl ether, diisopentyl ether, di-sec-pentyl ether, di-tert-pentyl ether, and di-n-hexyl ether. These solvents can be used alone or in combination. In addition to the solvents mentioned above, aromatic solvents such as toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, and mesitylene can also be used. 4-Methyl-2-pentanol is preferred as the rinsing solution. Rinsing is effective in minimizing the risk of resist pattern collapse and defect formation. However, rinsing is not always necessary. Omitting rinsing reduces the amount of solvent used.

[0099] The present invention will be further described in detail below with reference to embodiments, so that those skilled in the art can implement it based on the description.

[0100] It should be noted that, unless otherwise specified, the experimental methods described in the following implementation plan are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified.

[0101] Example:

[0102] Acid diffusion control agent (B)

[0103] Fluorinated resin (C)

[0104] Resin C-1: weight average molecular weight Mw = 7000, PDI = 1.8.

[0105]

[0106] Solvent (D) D-1: PGMEA D-2: Cyclohexanone D-3: γ-Butyrolactone

[0107] Other additives (E)

[0108]

[0109] <Synthesis of Monomers>

[0110] Synthesis example 1

[0111] The monomer M-1 was obtained by the following synthesis method.

[0112]

[0113] Synthesis of intermediates 1-4:

[0114] Add 4-hydroxythiophenol (1.0 eq), 2-(4-bromophenyl)ethylene oxide (1.0 eq), cuprous iodide (0.1 eq), L-proline (0.2 eq), and cesium carbonate (2.0 eq) to a dry reaction flask. Add anhydrous DMF (substrate concentration 0.1~0.2 mol / L), and completely purge with nitrogen (repeated 3 times). Heat to 90℃ with stirring and maintain the temperature for 24 hours. h, TLC was used to monitor the reaction until the starting material was completely consumed (developing solvent: petroleum ether / ethyl acetate = 5:1, UV lamp at 254 nm for color development); after the reaction was completed, the mixture was cooled to room temperature, filtered to remove insoluble inorganic salts, and the filtrate was slowly poured into an ice-water system (the volume of ice-water was 3 to 4 times the volume of the filtrate). The mixture was extracted three times with ethyl acetate (each extraction solvent was 1 / 2 the volume of the filtrate). The organic phases were combined, washed twice with saturated brine, dried overnight with anhydrous sodium sulfate, filtered to remove the solvent under reduced pressure, and the crude product was purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 8:1) to give a white solid intermediate 1-1 (a diaryl sulfide containing phenolic hydroxyl and epoxy groups), with a yield of 68%.

[0115] Add intermediate 1-1 (1.0 eq) to a dry reaction flask, add a methanol / water mixed solvent (volume ratio 4:1, substrate concentration 0.05~0.1 mol / L), stir to dissolve, and cool to 0~5℃ in an ice bath. Slowly add sodium periodate (1.0 eq) in portions. After the addition is complete, maintain the reaction at 0~5℃ for 2 h, then naturally warm to room temperature and continue the reaction for 4 h. Monitor the reaction by TLC until the starting material is completely consumed (developing solvent: petroleum ether / ethyl acetate = 3:1, UV lamp at 254 nm). After the reaction is complete, add saturated sodium sulfite solution to the system to quench excess oxidant (until starch-KI test paper does not turn blue). Concentrate under reduced pressure to remove methanol. Extract the remaining aqueous solution three times with ethyl acetate. Combine the organic phases, wash once with saturated brine, dry with anhydrous sodium sulfate, filter to remove solvent under reduced pressure, and purify the crude product by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 5:1) to obtain a white solid intermediate 1-2 (diaryl sulfoxide) in 82% yield.

[0116] Under anhydrous nitrogen protection, intermediate 1-2 (1.0 eq) was added to a dry reaction flask, and anhydrous tetrahydrofuran was added to prepare a substrate concentration of 0.1–0.2 mol / L. The mixture was stirred and dissolved. The system was cooled to -78°C, and a 1.0 mol / L solution of p-fluorophenyl magnesium bromide tetrahydrofuran (1.2 eq) was slowly added dropwise. After the addition was complete, the reaction was maintained at low temperature for 3 h, and then slowly raised to room temperature with stirring for 2 h. The reaction of the starting material was monitored by TLC until complete. After the reaction was completed, the mixture was cooled to 0°C in an ice bath, and the reaction was quenched by slowly adding saturated ammonium chloride solution. The mixture was stirred and allowed to stand for separation. The aqueous phase was extracted twice with dichloromethane. All organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the solvent was removed under reduced pressure. The crude product was purified by silica gel column chromatography (eluent: dichloromethane / methanol = 30:1) to give a pale yellow solid intermediate 1-3 in 75% yield.

[0117] Add intermediate 1-3 (1.0 eq) to a dry reaction flask, add anhydrous dichloromethane (substrate concentration 0.05 mol / L), stir to dissolve, and then cool in an ice bath to 0-5°C. At ℃, triethylamine (1.5 eq) and 4-dimethylaminopyridine (0.1 eq) were added sequentially, followed by the slow addition of methacryloyl chloride (1.2 eq). After the addition was complete, the reaction was maintained at 0-5℃ for 1 h, and then the temperature was raised to room temperature and the reaction was continued for 3 h. The reaction was monitored by TLC until the starting material was completely consumed (developing solvent: dichloromethane / methanol = 25:1, UV light at 254 nm). After the reaction was completed, ice water was added to quench the reaction. After separation, the aqueous phase was extracted twice with dichloromethane. The organic phases were combined and washed sequentially with 0.5 mol / L dilute hydrochloric acid, saturated sodium bicarbonate solution, and saturated brine. The mixture was dried over anhydrous sodium sulfate, filtered to remove the solvent under reduced pressure, and the crude product was purified by silica gel column chromatography (eluent: dichloromethane / methanol = 40:1) to give a white solid intermediate 1-4, with a yield of 70%.

[0118]

[0119] 4-Hydroxycyclohexylacetic acid (1.0 eq), anhydrous DMF, and anhydrous potassium carbonate (2.0 eq) were added to a dry reaction flask. The mixture was stirred at room temperature for 30 min under nitrogen protection to activate the alicyclic hydroxyl groups. Benzyl bromide (1.2 eq) was slowly added dropwise. After the addition was complete, the temperature was raised to 60 °C and maintained for 12 h. After the reaction was completed, the mixture was cooled to room temperature, poured into an ice-water mixture, extracted three times with ethyl acetate, and the organic phases were combined. The mixture was washed with saturated brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 5:1) to give a white solid intermediate a-1, with a yield of 85%.

[0120] Add intermediate a-1 (1.0 eq), anhydrous dichloromethane, and catalytically added N,N-dimethylformamide (0.1 eq) to a dry reaction flask, and cool to 0°C in an ice bath. ℃; slowly add oxalyl chloride (1.2 eq), and stir for 2 h after the addition is complete. TLC confirms that the raw material is completely converted into the acyl chloride intermediate; take a dry reaction flask, add sodium sulfide (1.5 eq) and tetrahydrofuran, and add iodomethane (1.5 eq) dropwise under ice bath conditions. After the addition is complete, raise the temperature to room temperature and stir for 1 h to prepare the sodium methyl dithiocarbamate reaction solution; slowly add the prepared acyl chloride solution to the sodium methyl dithiocarbamate system, and stir for 6 h at room temperature; after the reaction is complete, quench with saturated sodium bicarbonate aqueous solution, separate the liquid and extract the aqueous phase twice with dichloromethane, combine all organic phases, wash with saturated brine, dry with anhydrous sodium sulfate, filter, concentrate under reduced pressure, and purify the crude product by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 10:1) to obtain yellow oily liquid intermediate a-2, with a yield of 78%.

[0121] Intermediate a-2 (1.0 eq) and anhydrous dichloromethane were added to a dry reaction flask, and the temperature was lowered to -78°C. Diethylaminosulfur trifluoride (DAST, 3.0 eq) was slowly added dropwise. After the addition was completed, the temperature was slowly raised to 0°C, and the reaction was maintained at this temperature for 8 hours under nitrogen protection. After the reaction was complete as monitored by TLC, the reaction solution was slowly added dropwise to a saturated sodium bicarbonate aqueous solution for low-temperature quenching. The mixture was separated, and the aqueous phase was extracted twice with dichloromethane. The organic phases were combined, washed with saturated brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using pure petroleum ether as the eluent to obtain a colorless oily liquid intermediate a-3 with a yield of 65%.

[0122] Intermediate a-3 (1.0 eq) and dichloromethane were added to the reaction flask, and the mixture was cooled to 0°C in an ice bath. m-chloroperoxybenzoic acid (m-CPBA, 1.1 eq) was added in portions, and the mixture was kept at 0°C with stirring for 2 h. TLC monitoring confirmed the complete conversion of the sulfide to sulfoxide groups. After the reaction was complete, saturated sodium sulfite solution was added to quench excess oxidant. The mixture was separated, and the aqueous phase was extracted twice with dichloromethane. The combined organic phases were washed successively with saturated sodium bicarbonate solution and saturated brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 3:1) to obtain a white solid intermediate a-4, with a yield of 90%.

[0123] Intermediate a-4 (1.0 eq) and anhydrous tetrahydrofuran were added to a dry reaction flask, and the temperature was lowered to -78°C. A 1.0 mol / L solution of potassium bis(trimethylsilyl)amino(KHMDS) tetrahydrofuran (1.2 eq) was slowly added dropwise, and the mixture was stirred at low temperature for 30 min to generate ortho-carbanions. DAST (2.0 eq) was then added, and the system was slowly raised to room temperature. The mixture was stirred under nitrogen protection for 12 h. After the reaction was completed, the system was quenched in ice water, extracted three times with diethyl ether, and the organic phases were combined. The mixture was washed with saturated brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using petroleum ether as the eluent to obtain a colorless oily liquid intermediate a-5 in 55% yield.

[0124] Intermediate a-5 (1.0 eq), isopropanol, sodium bisulfite (3.0 eq), and azobisisobutyronitrile (AIBN, 0.1 eq) were added to the reaction flask. The mixture was completely purged with nitrogen three times, and the temperature was raised to 80 °C and maintained for 24 h. After the reaction was completed, the mixture was cooled to room temperature, filtered to remove insoluble solid impurities, and the filtrate was concentrated under reduced pressure to remove the solvent. The crude product was purified by recrystallization from ethanol to obtain a white solid intermediate a-6 with a yield of 60%.

[0125] Intermediate a-6 (1.0 eq), methanol, and 10% palladium on carbon (Pd / C, feed ratio 0.1) were added to the reaction flask. The mixture was completely purged with hydrogen three times and stirred for 12 h at room temperature and atmospheric pressure. TLC monitoring confirmed that the benzyl protecting group was completely removed. After the reaction was completed, the palladium on carbon catalyst was removed by filtration, and the filtrate was concentrated under reduced pressure to remove the solvent, yielding a white solid intermediate a-7 with a yield of 95%.

[0126]

[0127] Intermediates 1-4 (1.0 eq) and a-7 (1.0 eq) were placed in a dichloromethane / water two-phase system and stirred at room temperature for 12 h to complete the anion exchange reaction. After the reaction was completed, the aqueous phase was extracted three times with dichloromethane, and all organic phases were combined. The organic phase was washed multiple times with deionized water, dried with anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to remove the solvent. The crude product was fully dissolved in anhydrous tetrahydrofuran, and sodium hydride (1.3 eq) was slowly added at low temperature. The reaction was stirred at room temperature overnight to complete the reaction. After cooling in an ice bath, pure water was slowly added dropwise to quench the reaction. The product was extracted multiple times with dichloromethane, and the organic phases were combined, washed with water, purified, dried, concentrated under reduced pressure, and dried under vacuum to finally obtain the target compound M-1 with a yield of 65%.

[0128] Synthesis example 2

[0129] Monomer M-2 was prepared by replacing 4-hydroxycyclohexylacetic acid in Synthesis Example 1 with 3-hydroxyadamantane-1-acetic acid, following the synthesis method of Synthesis Example 1.

[0130]

[0131]

[0132] Synthesis example 3

[0133] Monomer M-3 was prepared by replacing 4-hydroxycyclohexylacetic acid in Synthesis Example 1 with 2-(3-hydroxybicyclo[1.1.1]pent-1-yl)acetic acid and following the synthesis method of Synthesis Example 1.

[0134]

[0135] Synthesis example 4

[0136] Monomer M-4 was prepared by replacing 2-(4-bromobenzyl)ethylene oxide with 2-(4-bromophenyl)ethylene oxide according to the synthesis method of Synthesis Example 1.

[0137]

[0138] Synthesis example 5

[0139] Monomer M-5 was prepared by replacing 2-(4-bromophenyl)ethylene oxide in Synthesis Example 1 with 6-BROMO-1A,2,3,7B-TETRAHYDRO-1-OXA-CYCLOPROPA[A] NAPHTHALENE (CAS No. 75693-20-8) according to the synthesis method of Synthesis Example 1.

[0140]

[0141] Synthesis example 6

[0142] Monomer M-6 was prepared by replacing 2-(4-bromophenyl)epoxyethylene in Synthesis Example 1 with 8-Oxabicyclo[5.1.0]octane, 1-(3-bromophenyl)- (CAS No. 11615678-74-4) according to the synthesis method of Synthesis Example 1.

[0143]

[0144] Synthesis Example 7

[0145] Monomer M-7 was prepared by replacing 2-(4-bromophenyl)epoxide in Synthesis Example 1 with 5-bromo-2,3-dihydrospirocyclic [indene-1,2'-epoxyethylene (CAS No. 1026796-25-7)] and following the synthesis method of Synthesis Example 1.

[0146]

[0147] Synthesis example 8

[0148] By replacing 2-(4-bromophenyl)-2-methylethylene oxide in Synthesis Example 1 above with 2-(4-bromophenyl)ethylene oxide, monomer M-8 was prepared according to the synthesis method of Synthesis Example 1 above.

[0149]

[0150] Synthesis example 9

[0151] Monomer M-9 was prepared by replacing 4-hydroxycyclohexanepropanoic acid (CAS No. 500793-45-3) in Synthesis Example 1 above with 4-hydroxycyclohexanepropanoic acid (CAS No. 500793-45-3) and following the synthesis method of Synthesis Example 1 above.

[0152]

[0153] Synthesis example 10

[0154] Monomer M-10 was prepared by replacing 4-hydroxycyclohexylacetic acid in Synthesis Example 1 with 4-(4-hydroxycyclohexyl)butyric acid, following the synthetic method of Synthesis Example 1. 4-(4-hydroxycyclohexyl)butyric acid can be prepared by the hydrolysis of ethyl 4-(4-hydroxycyclohexyl)butyrate.

[0155]

[0156] Synthesis example 11

[0157] Monomer M-11 was prepared by replacing 4-hydroxycyclohexylacetic acid in Synthesis Example 1 with 3-(3-Hydroxy-adamantan-1-yl)-propionic acid (CAS No. 256954-77-5) according to the synthesis method of Synthesis Example 1.

[0158]

[0159] Synthesis example 12

[0160] By replacing 2-(4-bromophenyl)epoxide in Synthesis Example 1 with bromobenzene, monomer M-12 was prepared according to the synthesis method of Synthesis Example 1.

[0161]

[0162] Synthesis example 13

[0163] By replacing 4-hydroxycyclohexylacetic acid in Synthesis Example 1 with 4-hydroxycyclohexanecarboxylic acid, monomer M-13 was prepared according to the synthesis method of Synthesis Example 1.

[0164]

[0165] Synthesis Example 14

[0166] By replacing 4-hydroxycyclohexylacetic acid in Synthesis Example 1 with 3-hydroxypropionic acid, monomer M-14 was prepared according to the synthesis method of Synthesis Example 1.

[0167]

[0168] <Polymer Synthesis>

[0169] In addition to M-1 to M-14 mentioned above, other monomers used to synthesize the following different polymers are as follows:

[0170]

[0171] Preparation Example 1 (Synthesis of Polymer (A-1))

[0172] Under a nitrogen protective atmosphere, 18.92 g of monomer M-1, 63.79 g of monomer m1, 44.61 g of monomer m2, and 76.62 g of monomer m3 were added sequentially to a reaction flask. Then, 2.52 g of initiator 2,2'-azobis(2-methylpropionic acid) dimethyl ester (AIBME) and 8.03 g of chain transfer agent 2-mercaptoethanol were added, along with 500 g of butanone. The mixture was stirred and dissolved to prepare a monomer-initiator mixed solution.

[0173] In a separate reaction vessel, add 150g of butanone, stir under nitrogen protection, and heat to 80°C. Add the monomer-initiator mixture at a uniform rate over 4 hours. After the addition is complete, maintain the system temperature at 80°C and continue stirring for 2 hours, then allow it to cool naturally to room temperature.

[0174] The obtained polymerization reaction solution was slowly added dropwise to 6000g of methanol under vigorous stirring, and a copolymer solid precipitated out. The solid product was collected by filtration, washed twice with 3000g of methanol, and dried under vacuum at 50℃ for 20h to obtain a white powder polymer A-1 (72g, yield 72%).

[0175] The polymer was tested and found to have a weight-average molecular weight (Mw) of 16,900. Characterization analysis by ¹³C-NMR showed that the molar percentages of repeating units derived from monomers M-1, m1, m2, and m3 in the polymer were 3.0%, 35.1%, 16.7%, and 45.2%, respectively.

[0176] <Synthesis of polymers (A-2)~(A-18) and polymers (A1)~(A5)>

[0177] Except for changing the monomers used and their amounts, polymers (A-2) to (A-18) and polymers (A1) to (A5) were synthesized in the same manner as the synthesis example of polymer (A-1). The proportions (molar ratios), Mw, and PDI of each structural unit are shown in Table 1.

[0178] Table 1

[0179] <Preparation of the resist composition>

[0180] Example 1

[0181] 100 parts by weight of polymer (A-1), 2.0 parts by weight of acid diffusion control agent (B-1), 3.5 parts by weight of fluorinated resin (C-1), 2100 parts by weight of solvent (D-1), 990 parts by weight of solvent (D-2), and 30 parts by weight of solvent (D-3) were mixed. The resulting mixed solution was filtered through a filter with a pore size of 0.20 μm to prepare the resist composition (R-1).

[0182] Examples 2-20 and Comparative Examples 1-5

[0183] Except for using the types and amounts of each component shown in Table 2 below, the resist compositions (R-2) to (R-20) and (R1) to (R5) were prepared in the same manner as in Example 1.

[0184] <Formation of resist patterns>

[0185] A base antireflective coating material (ARC66) was spin-coated onto a 12-inch silicon wafer using a spin coater (CLEAN TRACK Lithius Pro i, Tokyo Electron, Ltd.) and baked at 205°C for 60 seconds to form a 105 nm thick base antireflective coating. Then, a photoresist composition was coated onto the base antireflective coating using a spin coater, pre-baked (PB) (90°C, 60 seconds), and cooled (23°C, 30 seconds) to form a 100 nm thick photoresist film. The photoresist film was exposed under optimal focusing conditions using an ArF immersion scanner (NSR-S610C, Nikon Precision, Ltd.) (NA: 1.3, quadrupole). The exposure method was 1 / 4 projection exposure. The mask dimensions were 0.220 μm chromium / 0.440 μm pitch, with a mask deviation of 0 nm. The photoresist film was baked on a hot plate at 100°C for 60 seconds for PEB treatment, followed by cooling on a cold plate at 23°C for 30 seconds. Then, the photoresist film was developed in a liquid bath using butyl acetate developer (30 seconds) and rinsed with 4-methyl-2-pentanol (7 seconds). Finally, the photoresist film was spin-dried at 2000 rpm for 15 seconds to form a negative photoresist pattern with an aperture of 55 nm and a spacing of 110 nm.

[0186] <Evaluation Methods>

[0187] (1) Sensitivity test.

[0188] Observe the resist pattern under an electron microscope, exposure dose (mJ / cm). 2 The optimal dose (Eop) is a pore pattern with a spacing of 110 nm and a pore size of 55 nm. The smaller this value, the higher the sensitivity.

[0189] (2) Resolution

[0190] At the aforementioned optimal exposure level, the size of the smallest resolvable resist pattern was measured while varying the size of the mask pattern forming L / S (1L / 1S), and this measured value was taken as the resolution. The smaller the value, the better the resolution.

[0191] (3) Critical Dimensional Uniformity (CDU) Test

[0192] The hole pattern (diameter: 55 nm) formed on the photoresist film on the substrate under optimal dosage was observed from above using a scanning electron microscope (Hitachi High-Tech Corporation CG4000). The dimensions of 50 holes were measured, and the size variation (CDU) was defined as three times the standard deviation (σ) obtained from the results. The smaller this value, the smaller and better the variation in hole diameter.

[0193] (4) Depth of focus (DOF) test

[0194] When using a dot-matrix patterned mask to form aperture patterns with diameters in the range of 55 nm ± 10% by reducing projected exposure, the focusing amplitude is defined as the depth of focus (DOF). A dot-matrix pattern is pre-formed on the dot-matrix patterned mask to obtain aperture patterns with a diameter of 55 nm and a spacing of 110 nm. When the depth of focus value is large, the change in patterning capability caused by focusing variations is considered small.

[0195] The evaluation results are shown in Table 2 below.

[0196] Table 2 .

[0197] As shown in Table 2, compared with Comparative Examples 1-5, the resist composition of the present invention fundamentally eliminates the problem of uneven distribution of small molecules by firmly attaching PAG to the polymer backbone in the form of covalent bonds, making it an inherent part of the resin. After exposure, the acid generated by photolysis is fixed on the polymer chain, and its initial distribution is determined by the intrinsic uniformity of the polymer chain, thereby ensuring the uniformity of acid distribution. The resist composition of the present invention contains an acid-responsive solubility conversion unit, which can open the epoxy group under acid catalysis to generate two strongly polar hydroxyl groups, resulting in a sharp increase in polarity in local areas. At the same time, the newly generated active hydroxyl groups may also undergo slight intermolecular crosslinking with other functional groups in the polymer system to form an effective three-dimensional network structure. This dual mechanism of "sharp increase in polarity" and "physical crosslinking" leads to a sharp decrease in the solubility of the exposed area in the organic solvent developer, thereby obtaining extremely high dissolution contrast. Ultimately, the resist composition of the present invention can achieve high sensitivity and high resolution, while also possessing excellent CDU performance and greater depth of focus.

[0198] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention, and further modifications can be readily implemented by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and embodiments shown and described herein.

Claims

1. A compound, characterized in that, Its structure is shown in general formula (1): In formula (1), R1 is methyl, trifluoromethyl or hydrogen atom, R2 is substituted or unsubstituted saturated cycloalkyl group with 4 to 12 carbon atoms, R3 is a group containing epoxy functional group, wherein the epoxy functional group is located at the end of the molecule, and m is any integer between 1 and 3.

2. A polymer, characterized in that, It contains the structural units of the compound of formula (1) as described in claim 1.

3. A polymer as described in claim 2, characterized in that, The saturated cycloalkyl group is selected from at least one of the following structures: Preferred .

4. A polymer as described in claim 2, characterized in that, The epoxy-functionalized group is selected from at least one of the following structures: , Preferred .

5. A polymer as described in claim 2, characterized in that, The preferred value of m is 1.

6. A polymer as claimed in claim 2, characterized in that, The content of the structural units of the compound shown in formula (1) is 1-15 mol, more preferably 3-10 mol.

7. A photoresist composition, characterized in that, It comprises the polymer (A) according to any one of claims 2-6, the acid diffusion control agent (B), the fluorinated resin (C), and the organic solvent (D).

8. A photoresist composition as described in claim 7, characterized in that, The polymer (A) further comprises structural units having acid-dissociable groups as shown in formula (A-1) and structural units having lactone groups as shown in formula (A-2): ， In formulas (A-1) and (A-2), R4 independently represents a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; R5 represents an acid-unstable group; R6 represents a hydrocarbon group with 1 to 10 carbon atoms; X represents an oxygen atom, an ester group, a carbonate group, or an imino group; R7 represents a monovalent organic group containing a lactone structure; and n is any integer between 0 and 10.

9. A photoresist composition as described in claim 8, characterized in that, The polymer (A) is a quaternary or pentagonal copolymer.

10. A method for forming a pattern, characterized in that, Includes the following steps: (1) Forming a resist film on a substrate using the photoresist composition according to any one of claims 7-9; (2) Expose the above-mentioned resist film; (3) After baking, the exposed resist film is developed with a developer to obtain a photoresist pattern.

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