Quinoxaline diketone polymer, preparation method thereof, hard mask composition and pattern forming method

Abstract

The invention belongs to the technical field of photoetching, and provides a quinoxaline diketone polymer and a preparation method thereof, a hard mask composition and a pattern forming method. The quinoxaline diketone polymer has a structure as shown in a formula 1, and in the formula 1, R1 and R2 are independently hydrogen, an alkyl group with a carbon atom number of 1-10 or a substituted or unsubstituted aryl group with a carbon atom number of 6-30; and R3 is hydrogen or alkyl with the carbon atom number of 1-6. The hard mask formed by the hard mask composition has the characteristics of good heat resistance, strong etching resistance and low shrinkage rate after curing. Formula 1

Description

Technical Field

[0001] This invention belongs to the field of photolithography technology, specifically relating to a quinoxaloline dione polymer and its preparation method, a hard mask composition, and a patterning method. Background Technology

[0002] As semiconductor technology advances towards higher integration and faster computing speeds, the requirements for controlling the pattern size in photolithography processes are becoming increasingly stringent. To obtain ultra-fine patterns with precision dimensions ranging from several nanometers to tens of nanometers, existing technological approaches mainly revolve around two core aspects: first, promoting the development of shorter wavelengths for photolithography light sources; and second, effectively preventing the collapse of fine photoresist patterns by gradually reducing the thickness of the photoresist film.

[0003] However, reducing the thickness of the photoresist film directly decreases its blocking ability in subsequent etching processes, making it insufficient to protect the underlying material layer, thus leading to a decrease in pattern transfer fidelity. To resolve this contradiction and achieve finer etched patterns, it is crucial to place an intermediate layer of inorganic or organic film with excellent etching resistance between the photoresist and the material layer. This film layer must have a removal rate much lower than that of the photoresist above it in the etching environment, thus serving as a reliable medium for pattern transfer. This key structure is called the "resist underlayer," also widely known as the "hard mask," and its function is to ensure that ultra-fine patterns are completely and accurately replicated in multi-layer material stacks.

[0004] Currently, chemical vapor deposition (CVD) is widely used to prepare inorganic hard mask layers primarily composed of silicon nitride and amorphous carbon. However, this method suffers from problems such as complex processes, difficulty in controlling film uniformity, and high equipment investment costs. In contrast, spin-coated hard mask compositions are gradually becoming a viable alternative to CVD due to their advantages of simple processes, good film uniformity, and relatively low cost. Currently, commercially available spin-coated hard mask compositions often use high-carbon-content polymers to improve etching resistance, but these materials often have insufficient heat resistance. In photolithography, poor heat resistance can easily lead to pattern deformation, affecting pattern accuracy; simultaneously, during the high-temperature curing stage, these materials typically exhibit high film shrinkage, affecting the resolution of the photoresist pattern and limiting their application in advanced processes. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, the present invention aims to provide a quinoxalool dione polymer and its preparation method, as well as a hard mask composition comprising the quinoxalool dione polymer and a patterning method. The hard mask formed from the hard mask composition exhibits good heat resistance, strong etching resistance, and low shrinkage after curing.

[0006] In a first aspect, the present invention provides a quinoxaline dione polymer having the structure shown in Formula 1: Formula 1, In Equation 1, n is an integer from 1 to 200; R1 and R2 may be the same or different, and each is independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, and the substituent is an alkyl group having 1 to 6 carbon atoms; R3 is hydrogen or an alkyl group having 1 to 6 carbon atoms; R4 is or , in," " indicates a connecting bond, where R5 is hydrogen, an alkyl group with 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group with 6 to 30 carbon atoms, and the substituent is a hydroxyl group; L is an arylene with 6 to 18 carbon atoms.

[0007] In some embodiments of the present invention, the weight-average molecular weight of the quinoxaline dione polymer is 3,000 to 30,000, and the molecular weight distribution index is 1.30 to 3.50.

[0008] In a second aspect, the present invention provides a method for preparing the quinoxaloline dione polymer described in the first aspect of the present invention, the method comprising: subjecting a quinoxaloline dione monomer with the structure shown in Formula 2 to a polycondensation reaction with an aldehyde compound to form the quinoxaloline dione polymer. Equation 2, In Formula 2, R1 and R2 may be the same or different, and each is independently hydrogen, an alkyl group with 1 to 10 carbon atoms, or a substituted or unsubstituted aryl group with 6 to 30 carbon atoms, and the substituent is an alkyl group with 1 to 6 carbon atoms; R3 is hydrogen or an alkyl group with 1 to 6 carbon atoms.

[0009] In some embodiments of the present invention, the aldehyde compound is selected from monohydric aliphatic aldehydes and / or monohydric aromatic aldehydes.

[0010] Thirdly, the present invention provides a hard mask composition comprising a solvent, a polymer, a catalyst, a crosslinking agent, a surfactant, and a plasticizer, wherein the polymer is a quinoxaline dione polymer as described in the first aspect of the present invention.

[0011] In some embodiments of the present invention, based on the total mass of the hard mask composition, the polymer has a mass content of 4% to 25%, the crosslinking agent has a mass content of 0.3% to 3%, the catalyst has a mass content of 0.005% to 0.1%, the surfactant has a mass content of 0.01% to 0.1%, and the plasticizer has a mass content of 0.4% to 2.5%.

[0012] Fourthly, the present invention provides a pattern forming method, comprising the following steps: Provide a material layer on the substrate; The hard mask composition according to the third aspect of the present invention is applied to the material layer to form a hard mask; A silicon-containing thin layer is formed on the hard mask; A photoresist resist layer is formed on the silicon-containing thin layer; The photoresist resist layer is exposed and developed to form a photoresist pattern; The silicon-containing thin layer and the hard mask are selectively removed using the photoresist pattern to expose a portion of the material layer; Etch the exposed portion of the material layer.

[0013] The polymer provided by this invention incorporates a rigid aromatic heterocyclic structure of quinoxaline dione as a side group on its main molecular chain. This structure serves as a stable molecular scaffold, significantly enhancing the polymer's thermal stability and ensuring morphological stability even under the high-temperature conditions of photolithography, thereby effectively preventing pattern deformation. Simultaneously, the synergistic effect between carbon atoms and heteroatoms such as nitrogen and oxygen in this fused-ring framework forms a densely cross-linked protective layer in the etching environment, endowing the film with excellent etching resistance. In particular, the quinoxaline dione side groups possess significant steric hindrance and a rigid planar structure, effectively restricting the free movement and tight stacking of molecular chains during polymer curing, significantly suppressing film volume shrinkage and ensuring dimensional accuracy of pattern transfer.

[0014] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Detailed Implementation

[0015] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0016] The "scope" disclosed in this invention is defined in the form of a lower limit and / or an upper limit, whereby a given scope is defined by selecting a lower limit and / or an upper limit. This scope may or may not include endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form an undefined scope, and any lower limit can be combined with other lower limits to form an undefined scope, similarly, any upper limit can be combined with any other upper limit to form an undefined scope. Furthermore, each individually disclosed point or single value can itself serve as a lower or upper limit and can be combined with any other point or single value, or with other lower or upper limits, to form an undefined scope.

[0017] Unless otherwise specified, all embodiments and optional embodiments of the present invention may be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present invention.

[0018] In this invention, the alkyl group having 1 to 10 carbon atoms can include straight-chain alkyl groups having 1 to 10 carbon atoms and branched alkyl groups having 3 to 10 carbon atoms. Specifically, the number of carbon atoms in the alkyl group can be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. Specific examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, 1,1-dimethyl-n-propyl, 1,2-dimethyl-n-propyl, and 2,2-dimethyl-n-propyl. Propyl, 1-methyl-cyclopropyl, 2-methyl-cyclopropyl, 1-methyl-n-butyl, 2-methyl-n-butyl, 3-methyl-n-butyl, n-hexyl, 1-methyl-n-pentyl, 2-methyl-n-pentyl, 3-methyl-n-pentyl, 4-methyl-n-pentyl, 1,1-dimethyl-n-butyl, 1,2-dimethyl-n-butyl, 1,3-dimethyl-n-butyl, 1-ethyl-n-butyl, 2-ethyl-n-butyl, n-heptyl, isoheptyl, n-octyl, isooctyl, n-nonyl, isononyl. Specific examples of alkyl groups having 1 to 6 carbon atoms include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, and n-hexyl.

[0019] In this invention, substituted or unsubstituted aryl refers to an aryl group having substituents or an unsubstituted aryl group. A "substituted" aryl group means that the hydrogen atoms on the aryl group can be replaced by one or more substituents. When the number of substituents is greater than one, the substituents can be the same or different. It should be understood that the number of carbon atoms in a substituted aryl group refers to the total number of carbon atoms in the aryl group and its substituents. For example, a substituted aryl group with 18 carbon atoms means that the total number of carbon atoms in the aryl group and its substituents is 18.

[0020] In this invention, specific examples of aryl groups include, but are not limited to, phenyl, naphthyl, biphenyl, anthraceneyl, and pyreneyl. Specific examples of substituted aryl groups include, but are not limited to, alkyl-substituted phenyl groups and hydroxyl-substituted phenyl groups.

[0021] In this invention, arylene refers to a divalent group formed by the loss of a hydrogen atom from an aryl group.

[0022] In this invention, " "Indicates a linker bond. A non-positioned linker bond refers to a single bond extending from the ring system." The term "" indicates that one end of the linker can be connected to any position in the ring system through which the linker passes, and the other end is connected to the rest of the molecule. For example, as shown in formula f below, the naphthyl group represented by formula f is connected to other positions in the molecule through a non-positional linker extending from the middle of one side of the benzene ring. This means that it includes any possible connection mode shown in formulas f-1 and f-2.

[0023] .

[0024] In this invention, the non-positioning group involved on the ring indicates that the group can be connected at any position throughout the ring system. For example, as shown in formula e below, R is a non-positioning group, including any possible connection mode shown in formulas e-1 to e-3: .

[0025] A first aspect of the present invention provides a quinoxaline dione polymer having the structure shown in Formula 1: Formula 1, In Formula 1, n represents the degree of aggregation, which is an integer from 1 to 200, such as 1, 3, 5, 9, 10, 17, 20, 30, 50, 80, 100, 120, 150, 180, etc., and preferably an integer from 2 to 30; R1 and R2 may be the same or different, and each is independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, and the substituent is an alkyl group having 1 to 6 carbon atoms; R3 is hydrogen or an alkyl group having 1 to 6 carbon atoms; R4 is or , R5 is hydrogen, an alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, and the substituent is a hydroxyl group.

[0026] In some embodiments, R1 and R2 are each independently an alkyl group having 2 to 8 carbon atoms or an aryl group having 6 to 12 carbon atoms. As some preferred examples, R1 and R2 are each independently ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, phenyl, naphthyl, or biphenyl.

[0027] In some embodiments, R3 is hydrogen or an alkyl group having 1 to 4 carbon atoms, preferably hydrogen or methyl.

[0028] In some implementations, R4 is And R5 is hydrogen, an alkyl group having 1 to 4 carbon atoms, or any one of the following groups:

[0029] Further, R5 is hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, or any one of the following groups:

[0030] In other implementations, R4 is Furthermore, L is a phenylene or biphenylene group. Further, L is selected from any one of the following groups:

[0031] In this invention, the weight-average molecular weight (Mw) of the quinoxalool dione polymer can be 3000~30000, for example 3000, 5000, 6000, 6500, 7000, 7300, 7800, 8000, 8500, 8800, 9000, 10000, 15000, 20000, 22500, 26000, 30000, etc., preferably 5000~10000; the molecular weight distribution index (PDI) can be 1.30~3.50, for example 1.42, 1.53, 1.66, 1.85, 2.05, 2.24, 2.35, 2.65, 3.15, etc., preferably 1.45~2.30. The molecular weight and distribution of the polymer can be determined by gel permeation chromatography (GPC).

[0032] In this invention, the quinoxaline dione polymer can be formed by a condensation reaction between quinoxaline dione monomers and aldehyde compounds.

[0033] Therefore, a second aspect of the present invention provides a method for preparing the quinoxaloline dione polymer, comprising: subjecting a quinoxaloline dione monomer with the structure shown in Formula 2 to a polycondensation reaction with an aldehyde compound to form the quinoxaloline dione polymer: Equation 2, In Equation 2, the definitions of R1, R2 and R3 are as described in the first aspect of this invention, and will not be repeated here.

[0034] In some embodiments, the structure of the quinoxaloline dione monomer is shown below: .

[0035] In this invention, the aldehyde compound refers to a class of substances capable of undergoing a condensation reaction with the quinoxaline dione monomer to provide an R4 group for the quinoxaline dione polymer. The aldehyde compound may structurally include one or two aldehyde groups (specifically, the choice may be made according to the desired R4 group). According to some embodiments, the aldehyde compound is a monohydric aliphatic aldehyde and / or a monohydric aromatic aldehyde. Specific examples of the monohydric aliphatic aldehyde include, but are not limited to, at least one of formaldehyde, oligoformaldehyde, acetaldehyde, propionaldehyde, and butyraldehyde; specific examples of the monohydric aromatic aldehyde include, but are not limited to, at least one of benzaldehyde, naphthaldehyde, anthracene formaldehyde, pyrene formaldehyde, and p-hydroxybenzaldehyde. According to other embodiments, the aldehyde compound is a dihydric aromatic aldehyde, such as benzaldehyde or biphenyl dialdehyde.

[0036] In this invention, the molar ratio of the monomer to the aldehyde compound can be 1:(0.5~1.5), for example 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:1.2, 1:1.5, etc., preferably 1:(0.7~0.95).

[0037] In some embodiments, the polycondensation reaction is carried out in the presence of an acid catalyst. The acid catalyst can be an organic acid catalyst and / or an inorganic acid catalyst. Specific examples of organic acid catalysts include, but are not limited to, one or more of p-benzenesulfonic acid, formic acid, oxalic acid, benzoic acid, and salicylic acid; specific examples of inorganic acid catalysts include, but are not limited to, one or more of sulfuric acid, phosphoric acid, perchloric acid, nitric acid, and hydrochloric acid.

[0038] In some embodiments, the mass amount of the acid catalyst is 0.1% to 2.0% of the total mass of the quinoxaline dione monomer and the aldehyde compound, for example, 0.2%, 0.4%, 0.5%, 0.7%, 1%, 1.2%, 1.5%, 1.8%, etc.

[0039] In this invention, the polycondensation reaction can typically be carried out in the presence of a solvent. As specific examples, the solvent may be selected from at least one of tetrahydrofuran, propylene glycol monomethyl ether, propylene glycol dimethyl ether, propylene glycol monoethyl ether, and propylene glycol monomethyl ether acetate. According to some embodiments, the mass ratio of the solvent to the total amount of the quinoxalolinedione monomer and the aldehyde compound may be (4~16):1, for example, 4:1, 6:1, 8:1, 10:1, 12:1, 14:1, 16:1, etc.

[0040] In this invention, the temperature of the polycondensation reaction can be 60~200℃, for example 60℃, 80℃, 90℃, 100℃, 110℃, 120℃, 145℃, 150℃, 170℃, 190℃, 200℃, etc. The time of the polycondensation reaction can be selected according to the reaction temperature and the molecular weight of the target product, and is usually 5~48h, for example 5h, 8h, 10h, 12h, 15h, 18h, 20h, 24h, 25h, 30h, 40h, 45h, etc., preferably 8~25h.

[0041] A third aspect of the present invention provides a hard mask composition comprising a solvent, a polymer, a catalyst, a crosslinking agent, a surfactant, and a plasticizer.

[0042] In this invention, the polymer is a quinoxaloline dione polymer as described in the first aspect of this invention. Based on the total mass of the hard mask composition, the mass content of the polymer can be 4% to 25%, for example, 4%, 6%, 8%, 10%, 12%, 15%, 16%, 20%, 22%, 25%, etc.

[0043] In this invention, the crosslinking agent can react with the polymer to form a dense network backbone, and specific examples include, but are not limited to, at least one of: glycourea compounds (e.g., tetramethoxymethylglycourea), epoxy compounds, melamine, melamine derivatives, and aromatic compounds. Based on the total mass of the hard mask composition, the mass content of the crosslinking agent can be 0.3% to 3%, for example, 0.3%, 0.4%, 0.5%, 0.8%, 1%, 1.3%, 1.5%, 2%, 2.2%, 3%, etc.

[0044] In this invention, the catalyst is designed to reduce the activation energy required for the reaction between the crosslinking agent and the polymer, thereby improving the crosslinking efficiency. The catalyst can be an acid catalyst, specific examples of which include, but are not limited to, one or more of the following acidic compounds: p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium-p-benzenesulfonate, salicylic acid, camphorsulfonic acid, and phenylene disulfonic acid. Based on the total mass of the hard mask composition, the mass content of the catalyst can be 0.005% to 0.1%, for example, 0.005%, 0.007%, 0.01%, 0.02%, 0.03%, 0.05%, 0.08%, etc.

[0045] In this invention, the surfactant helps improve substrate wettability and film uniformity, and can be selected with reference to existing hard masks. As specific examples, the surfactant can be selected from one or more of polyoxyethylene alkyl ethers, polyoxyethylene alkyl aryl ethers, sorbitol fatty acid esters, and polyoxyethylene sorbitol fatty acid esters. Based on the total mass of the hard mask composition, the mass content of the surfactant can be 0.01% to 0.1%, for example, 0.01%, 0.03%, 0.05%, 0.06%, 0.08%, 0.1%, etc.

[0046] In this invention, the plasticizer improves the flowability of the hard mask composition and reduces the brittleness of the hard mask by regulating intermolecular forces. The plasticizer is typically selected from one or more of the following: phthalic acid derivatives (e.g., dimethyl phthalate, diethyl phthalate, diisobutyl phthalate), adipic acid derivatives (e.g., di-n-butyl adipate, diisobutyl adipate), maleic acid derivatives (e.g., di-n-butyl maleate, diethyl maleate), and stearic acid derivatives (e.g., n-butyl stearate, glyceryl stearate). Based on the total mass of the hard mask composition, the mass content of the plasticizer can be 0.4% to 2.5%, for example, 0.4%, 0.7%, 1.0%, 1.2%, 1.5%, 1.8%, 2.0%, 2.2%, 2.5%, etc.

[0047] In this invention, the solvent in the hard mask composition can be selected with reference to existing technology, as long as it has good solubility or dispersibility for other components in the composition. Specific examples include, but are not limited to, one or more of propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, cyclohexanone, and ethyl lactate. Based on the total mass of the hard mask composition, the solvent content can be 70% to 95%, for example, 70%, 75%, 80%, 85%, 90%, 93%, 95%, etc. As some embodiments, the total mass content of the solvent and other components is 100%.

[0048] The present invention does not particularly limit the preparation method of the hard mask composition. Exemplarily, the polymer, catalyst, crosslinking agent, surfactant and plasticizer can be added to the solvent and thoroughly mixed by mechanical stirring or ultrasonic treatment to form a homogeneous and stable solution. Then, the solution is filtered using a microporous filter with a pore size of 0.1~0.2μm, and the resulting filtrate is the hard mask composition.

[0049] A fourth aspect of the present invention provides a pattern forming method, comprising the following steps: (a) Providing a material layer on a substrate; (b) Applying the hard mask composition onto the material layer to form a hard mask; (c) Forming a silicon-containing thin layer on the hard mask; (d) A photoresist layer is formed on the silicon-containing thin layer; the photoresist layer is exposed and developed to form a photoresist pattern; (e) Using the photoresist pattern, selectively remove the silicon-containing thin layer and the hard mask to expose a portion of the material layer; (f) Etching the exposed portion of the material layer.

[0050] In this invention, the substrate can be a silicon wafer, a glass substrate, or a polymer substrate. The material layer is the material to be finally patterned, and can be a metal layer such as an aluminum layer or a copper layer, a semiconductor layer such as a silicon layer, or an insulating layer such as silicon dioxide or silicon nitride.

[0051] In this invention, the method for forming the hard mask can be as follows: spin-coating the hard mask composition onto the material layer, and heat-treating it at 200~500°C to form a hard mask. The heat treatment time can be 10s~10min, and the thickness of the spin coating is preferably 100~1000nm.

[0052] In this invention, the silicon-containing thin layer may be selected from at least one of silicon nitride, silicon oxide, and silicon oxynitride. The photoresist resist layer can be exposed using any one of ArF, KrF, or EUV light sources. Alternatively, a gas such as CHF3 / CF4 can be used to dry etch the material layer.

[0053] The following describes embodiments of the present invention. These embodiments are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0054] The following synthesis examples illustrate the preparation methods of the monomers used in the embodiments.

[0055] Synthesis Example 1: Synthesis of Monomer M1 (1) Dissolve 6-bromo-2,3(1H,4H)-quinoxaline dione (4.82 g, 20 mmol) in 200 mL of acetonitrile, add potassium carbonate (8.29 g, 60 mmol) with stirring, then add bromobutane (8.22 g, 60 mmol), and finally add solid potassium iodide catalyst (0.17 g, 1 mmol). Heat to reflux for reaction. After the starting material disappears as monitored by TLC, concentrate the resulting reaction solution under reduced pressure to obtain concentrated product. Dilute with DCM (dichloromethane, 100 mL), wash twice with 10 wt% sodium carbonate, combine the organic phases, dry the organic phase with anhydrous sodium sulfate, filter, concentrate under reduced pressure, and purify the crude product by silica gel (200~300 mesh) column chromatography to obtain intermediate IM-1 (6.17 g, yield 87.3%).

[0056]

[0057] (2) The intermediate IM-1 (3.53 g, 10 mmol), p-methoxyphenylboronic acid (1.52 g, 10 mmol), tetrakis(triphenylphosphine)palladium (0.35 g, 0.3 mmol), potassium carbonate (2.76 g, 20 mmol), 20 mL of toluene and 10 mL of water were placed in a three-necked flask and refluxed under nitrogen protection. The reaction was monitored by HPLC until the p-methoxyphenylboronic acid had completely reacted. The reaction was then stopped. The resulting reaction solution was cooled, allowed to stand, and separated. The resulting organic phase was washed twice with water and dried with anhydrous sodium sulfate. The solution was filtered, concentrated under reduced pressure, and the crude product was purified by silica gel (200-300 mesh) column chromatography to obtain monomer M1 (3.15 g, yield 82.8%).

[0058]

[0059] NMR characterization results of monomer M1, 1 H-NMR (400 MHz, CDCl3)δ(ppm): 7.86-6.75 (d, 7H,PhH), 4.42 (t, 4H, (-NCH2)2), 3.85 (s, 3H, -OCH3), 1.75 (m, 4H, (-NCH2CH2)2), 1.36 (m, 4H, (-CH2CH3)2), 0.91 (t, 6H, (-CH2CH3)2).

[0060] Synthesis Example 2: Synthesis of Monomer M2 (1) Dissolve 4.82 g, 20 mmol of 6-bromo-2,3(1H,4H)-quinoxaline dione in 200 mL of acetonitrile, add potassium carbonate (8.29 g, 60 mmol) with stirring, then add bromooctane (11.59 g, 60 mmol), and finally add solid potassium iodide catalyst (0.17 g, 1 mmol). Heat to reflux for reaction. After the starting material disappears as monitored by TLC, concentrate the resulting reaction solution under reduced pressure to obtain concentrated product. Dilute with 100 mL of DCM, wash twice with 10 wt% sodium carbonate, combine the organic phases, dry the organic phase with anhydrous sodium sulfate, filter, concentrate under reduced pressure, and purify the crude product by silica gel (200~300 mesh) column chromatography to obtain intermediate IM-2 (8.22 g, yield 88.3%).

[0061]

[0062] (2) The intermediate IM-2 (4.65 g, 10 mmol), p-methoxyphenylboronic acid (1.52 g, 10 mmol), tetrakis(triphenylphosphine)palladium (0.35 g, 0.3 mmol), potassium carbonate (2.76 g, 20 mmol), 20 mL of toluene and 10 mL of water were placed in a three-necked flask and refluxed under nitrogen protection. The reaction was monitored by HPLC until the p-methoxyphenylboronic acid had completely reacted. The reaction was then terminated, cooled, allowed to stand, and separated. The resulting organic phase was washed twice with water, dried with anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and the crude product was purified by silica gel (200-300 mesh) column chromatography to obtain monomer M2 (3.88 g, yield 78.8%).

[0063]

[0064] NMR characterization results of monomer M2, 1 H-NMR (400 MHz, CDCl3)δ(ppm): 7.92-6.87 (d, 7H,PhH), 4.45 (t, 4H, (-NCH2)2), 3.83 (s, 3H, -OCH3), 1.72 (m, 4H, (-NCH2CH2)2), 1.28 (m, 20H, (-CH2CH2CH2CH2CH2CH3)2), 0.89 (t, 6H, (-CH2CH3)2).

[0065] Synthesis Example 3: Synthesis of Monomer M3 Monomer M1 (3.80 g, 0.01 mol) and 50 mL of dichloromethane were placed in a three-necked flask and stirred thoroughly. Then, a solution of boron tribromide (12.53 g, 0.05 mol) in dichloromethane (50 mL) was slowly added dropwise under ice bath conditions (0 °C) for 30 min. After the addition was completed, the reaction was continued for 24 h. The resulting reaction solution was then slowly poured into ice water, and the pH was adjusted to neutral with a 10 wt% NaHCO3 aqueous solution. The solid precipitated out and was filtered to obtain monomer M3 (3.12 g, yield 85.1%).

[0066]

[0067] NMR characterization results of monomer M3, 1 H-NMR (400 MHz, CDCl3)δ(ppm): 9.68 (s, 1H, -OH), 7.94-6.85 (d, 7H, PhH), 4.43 (t, 4H, (-NCH2)2), 1.74 (m, 4H, (-NCH2CH2)2), 1.35(m, 4H, (-CH2CH3)2), 0.92 (t, 6H, (-CH2CH3)2).

[0068] Synthesis Example 4: Synthesis of Monomer M4 Monomer M2 (4.93 g, 0.01 mol) and 50 mL of dichloromethane were placed in a three-necked flask and stirred thoroughly. Then, a solution of boron tribromide (12.53 g, 0.05 mol) in dichloromethane (50 mL) was slowly added dropwise under ice bath conditions (0 °C) for 30 min. After the addition was completed, the reaction was continued for 24 h. The resulting reaction solution was then slowly poured into ice water, and the pH was adjusted to neutral with a 10 wt% NaHCO3 aqueous solution. The solid precipitated out and was filtered to obtain monomer M4 (4.01 g, yield 83.8%).

[0069]

[0070] NMR characterization results of monomeric M4, 1 H-NMR (400 MHz, CDCl3)δ(ppm): 9.69 (s, 1H, -OH), 7.93-6.84 (d, 7H, PhH), 4.44 (t, 4H, (-NCH2)2), 1.71 (m, 4H, (-NCH2CH2)2), 1.27(m, 20H, (-CH2CH2CH2CH2CH2CH3)2), 0.88 (t, 6H, (-CH2CH3)2).

[0071] Synthesis Example 5: Synthesis of Monomer M5 (1) Dissolve 6-bromo-2,3(1H,4H)-quinoxaline dione (4.82 g, 20 mmol) in 200 mL of acetonitrile, add potassium carbonate (8.29 g, 60 mmol) with stirring, add bromobenzene (9.42 g, 60 mmol) and solid potassium iodide catalyst (0.17 g, 1 mmol) in sequence, heat to reflux and react. After the starting material disappears as monitored by TLC, concentrate the resulting reaction solution under reduced pressure to obtain concentrated product, dilute with DCM, wash twice with 10 wt% sodium carbonate, combine the organic phases, dry the organic phase with anhydrous sodium sulfate, filter, concentrate under reduced pressure, and purify the crude product by silica gel (200~300 mesh) column chromatography to obtain intermediate IM-5 (5.83 g, yield 74.1%).

[0072]

[0073] (2) The intermediate IM-5 (3.93 g, 10 mmol), p-methoxyphenylboronic acid (1.52 g, 10 mmol), tetrakis(triphenylphosphine)palladium (0.35 g, 0.3 mmol), potassium carbonate (2.76 g, 20 mmol), 20 mL of toluene and 10 mL of water were placed in a three-necked flask and refluxed under nitrogen protection. The reaction was monitored by HPLC until the p-methoxyphenylboronic acid had completely reacted. The reaction was then terminated, cooled, allowed to stand, and separated. The resulting organic phase was washed twice with water, dried with anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and the crude product was purified by silica gel (200-300 mesh) column chromatography to obtain monomer M5 (3.24 g, yield 77.1%).

[0074]

[0075] NMR characterization results of monomer M5, 1 H-NMR (400 MHz, CDCl3) δ (ppm): 7.96-6.87 (m, 17H, PhH), 3.88 (s, 3H, -OCH3).

[0076] The following preparation examples illustrate the quinoxaloline dione polymers and their preparation methods of the present invention.

[0077] Preparation Example 1 At room temperature, monomer M1 (5.33 g, 0.014 mol), paraformaldehyde (0.36 g, 0.012 mol), 0.114 g of p-toluenesulfonic acid, and 51.18 g of propylene glycol monomethyl ether acetate (PGMEA) were added to a four-necked flask equipped with a thermometer, mechanical stirrer, reflux condenser, and water separator. Under nitrogen protection, the mixture was heated to 120 °C until the reactants were completely dissolved. The reaction system was then refluxed and reacted for 20 h. After the reaction was completed, the system was cooled to room temperature, and the resulting reaction solution was slowly added to methanol and stirred for 0.5 h. The precipitate was filtered, and the resulting filter cake was further washed twice with methanol and then dried under vacuum at 60 °C for 10 h to obtain a quinoxaline dione polymer with the structure shown in Formula 2-1, denoted as P1. P1 has Mw = 7730 and PDI = 2.18.

[0078] Preparation Example 2 At room temperature, monomer M3 (5.13 g, 0.014 mol), paraformaldehyde (0.36 g, 0.012 mol), 0.110 g p-toluenesulfonic acid, and 49.42 g PGMEA were added to a four-necked flask equipped with a thermometer, mechanical stirrer, reflux condenser, and water separator. Under nitrogen protection, the mixture was heated to 100 °C until the reactants were completely dissolved. The reaction system was then refluxed and reacted for 12 h. After the reaction was completed, the system was cooled to room temperature, and the resulting reaction solution was slowly added to methanol and stirred for 0.5 h. The precipitate was filtered, and the resulting filter cake was further washed twice with methanol and then dried under vacuum at 60 °C for 10 h to obtain a quinoxaline dione polymer with the structure shown in Formula 2-2, denoted as P2. P2 has Mw = 8120 and PDI = 2.26.

[0079] Preparation Example 3 At room temperature, monomer M1 (5.71 g, 0.015 mol), benzaldehyde (1.27 g, 0.012 mol), 0.140 g p-toluenesulfonic acid, and 62.83 g PGMEA were added to a four-necked flask equipped with a thermometer, mechanical stirrer, reflux condenser, and water separator. Under nitrogen protection, the temperature was raised to 120 °C. After the reactants were completely dissolved, the reaction system was refluxed and reacted for 20 h. After the reaction was completed, the system was cooled to room temperature, and the resulting reaction solution was slowly added to methanol and stirred for 0.5 h. The precipitate was filtered, and the resulting filter cake was further washed twice with methanol and then dried under vacuum at 60 °C for 10 h to obtain a quinoxaline dione polymer with the structure shown in Formula 2-3, denoted as P3. P3 has Mw = 7150 and PDI = 2.08.

[0080] Preparation Example 4 At room temperature, monomer M3 (5.13 g, 0.014 mol), benzaldehyde (1.27 g, 0.012 mol), 0.128 g p-toluenesulfonic acid, and 57.63 g PGMEA were added to a four-necked flask equipped with a thermometer, mechanical stirrer, reflux condenser, and water separator. Under nitrogen protection, the mixture was heated to 100 °C until the reactants were completely dissolved. The reaction system was then refluxed and reacted for 12 h. After the reaction was completed, the system was cooled to room temperature, and the resulting reaction solution was slowly added to methanol and stirred for 0.5 h. The precipitate was filtered, and the resulting filter cake was further washed twice with methanol and then dried under vacuum at 60 °C for 10 h to obtain a quinoxaline dione polymer with the structure shown in Formula 2-4, denoted as P4. P4 has an Mw of 7020 and a PDI of 2.15.

[0081] Preparation Example 5 At room temperature, monomer M3 (5.50 g, 0.015 mol), 1-naphthaldehyde (1.87 g, 0.012 mol), 0.147 g p-toluenesulfonic acid, and 66.34 g PGMEA were added to a four-necked flask equipped with a thermometer, mechanical stirrer, reflux condenser, and water separator. Under nitrogen protection, the mixture was heated to 100 °C until the reactants were completely dissolved. The reaction system was then refluxed and reacted for 12 h. After the reaction was completed, the system was cooled to room temperature, and the resulting reaction solution was slowly added to methanol and stirred for 0.5 h. The precipitate was filtered, and the resulting filter cake was further washed twice with methanol and then dried under vacuum at 60 °C for 10 h to obtain a quinoxaline dione polymer with the structure shown in Formula 2-5, denoted as P5. P5 has Mw = 7980 and PDI = 2.31. Preparation Example 6 At room temperature, monomer M3 (5.50 g, 0.015 mol), 9-anthracene carboxaldehyde (2.47 g, 0.012 mol), 0.159 g p-toluenesulfonic acid, and 71.75 g PGMEA were added to a four-necked flask equipped with a thermometer, mechanical stirrer, reflux condenser, and water separator. Under nitrogen protection, the temperature was raised to 120 °C. After the reactants were completely dissolved, the reaction system was refluxed and reacted for 18 h. After the reaction was completed, the system was cooled to room temperature, and the resulting reaction solution was slowly added to methanol and stirred for 1 h. The precipitate was filtered, and the resulting filter cake was further washed twice with methanol and then dried under vacuum at 60 °C for 10 h to obtain a quinoxaline dione polymer with the structure shown in Formula 2-6, denoted as P6. P6 has Mw = 8460 and PDI = 2.35.

[0082] Preparation Example 7 At room temperature, monomer M2 (6.90 g, 0.014 mol), paraformaldehyde (0.36 g, 0.012 mol), 0.145 g p-toluenesulfonic acid, and 65.32 g PGMEA were added to a four-necked flask equipped with a thermometer, mechanical stirrer, reflux condenser, and water separator. Under nitrogen protection, the temperature was raised to 120 °C. After the reactants were completely dissolved, the reaction system was refluxed and reacted for 20 h. After the reaction was completed, the system was cooled to room temperature, and the resulting reaction solution was slowly added to methanol and stirred for 0.5 h. The precipitate was filtered, and the filter cake was further washed twice with methanol and then dried under vacuum at 60 °C for 10 h to obtain a quinoxaline dione polymer with the structure shown in Formula 2-7, denoted as P7. P7 has Mw = 6450 and PDI = 1.83.

[0083] Preparation Example 8 At room temperature, monomer M4 (6.70 g, 0.014 mol), paraformaldehyde (0.36 g, 0.012 mol), 0.141 g p-toluenesulfonic acid, and 63.56 g PGMEA were added to a four-necked flask equipped with a thermometer, mechanical stirrer, reflux condenser, and water separator. Under nitrogen protection, the mixture was heated to 100 °C until the reactants were completely dissolved. The reaction system was then refluxed and reacted for 12 h. After the reaction was completed, the system was cooled to room temperature, and the resulting reaction solution was slowly added to methanol and stirred for 0.5 h. The precipitate was filtered, and the filter cake was further washed twice with methanol and then dried under vacuum at 60 °C for 10 h to obtain a quinoxaline dione polymer with the structure shown in Formula 2-8, denoted as P8. P8 has Mw = 6930 and PDI = 1.89.

[0084] Preparation Example 9 At room temperature, monomer M4 (7.18 g, 0.015 mol), benzaldehyde (1.27 g, 0.012 mol), 0.169 g p-toluenesulfonic acid, and 76.08 g PGMEA were added to a four-necked flask equipped with a thermometer, mechanical stirrer, reflux condenser, and water separator. Under nitrogen protection, the mixture was heated to 100 °C until the reactants were completely dissolved. The reaction system was then refluxed and reacted for 12 h. After the reaction was complete, the system was cooled to room temperature, and the resulting reaction solution was slowly added to methanol and stirred for 0.5 h. The precipitate was filtered, and the filter cake was further washed twice with methanol and then dried under vacuum at 60 °C for 10 h to obtain a quinoxaline dione polymer with the structure shown in Formula 2-9, denoted as P9. P9 has Mw = 7490 and PDI = 1.95.

[0085] Preparation Example 10 At room temperature, monomer M5 (5.89 g, 0.014 mol), benzaldehyde (1.27 g, 0.012 mol), 0.143 g p-toluenesulfonic acid, and 64.44 g PGMEA were added to a four-necked flask equipped with a thermometer, mechanical stirrer, reflux condenser, and water separator. Under nitrogen protection, the temperature was raised to 120 °C. After the reactants were completely dissolved, the reaction system was refluxed and reacted for 20 h. After the reaction was completed, the system was cooled to room temperature, and the resulting reaction solution was slowly added to methanol and stirred for 0.5 h. The precipitate was filtered, and the filter cake was further washed twice with methanol and then dried under vacuum at 60 °C for 10 h to obtain a quinoxaline dione polymer with the structure shown in Formula 2-10, denoted as P10. P10 has Mw = 8800 and PDI = 2.14.

[0086] Comparative Preparation Example 1 At room temperature, phenol (4.71 g, 0.05 mol), paraformaldehyde (1.50 g, 0.05 mol), 0.124 g p-toluenesulfonic acid, and 55.86 g PGMEA were added to a four-necked flask equipped with a thermometer, mechanical stirrer, reflux condenser, and water separator. Under nitrogen protection, the mixture was heated to 100 °C until the reactants were completely dissolved. The reaction system was then refluxed and reacted for 12 h. After the reaction was complete, the system was cooled to room temperature, and the resulting reaction solution was slowly added to methanol and stirred for 0.5 h. The precipitate was filtered, and the filter cake was further washed twice with methanol and then dried under vacuum at 60 °C for 10 h to obtain the reference polymer shown in Formula 2-11, denoted as D1, with Mw = 8200 and PDI = 1.86.

[0087] The polymers of Preparation Examples 1-10 and Comparative Preparation Example 1 have the following structures.

[0088]

[0089] The following examples illustrate the hard mask composition and its preparation method of the present invention.

[0090] Examples 1-10 The quinoxalool dione polymers P1 to P10 prepared in Preparation Examples 1 to 10 were added to clean bottles with catalyst, crosslinking agent, solvent, surfactant and plasticizer in the proportions shown in Table 1. The mixture was shaken until all components were completely dissolved. Then, each sample was filtered through a 0.2 μm PTFE membrane filter to obtain spin coating solution (i.e. hard mask composition).

[0091] The catalyst is p-toluenesulfonic acid, the crosslinking agent is tetramethoxymethyl urea, the solvent is propylene glycol monomethyl ether acetate (PGMEA), the surfactant is polyoxyethylene lauryl ether (purchased from TCI, product number P0711), and the plasticizer is dimethyl phthalate.

[0092] Comparative Example 1 The hard mask composition was prepared according to the method of Example 1, except that the quinoxalool dione polymer P1 was replaced with the reference polymer D1 of Comparative Preparation Example 1.

[0093] Table 1

[0094] Note: All percentages in Table 1 refer to mass percentages.

[0095] Test case The heat resistance, etching resistance, and film shrinkage of the hard mask compositions prepared in the above examples and comparative examples were tested according to the following methods.

[0096] 1. Sample Preparation Hard mask spin coating solution was applied to silicon wafers using a spin coater, and then heat-treated at 320°C for 120 s to form a hard mask with a thickness of approximately 4000 Å. Two sets of hard masks obtained using the same spin coating solution were used as test samples for heat resistance and etching resistance tests.

[0097] 2. Heat resistance test After a set of hard masks was broken into powder, its mass loss rate was tested using a thermogravimetric analyzer (TGA). The test conditions were: under a nitrogen atmosphere, the temperature was increased from 40℃ to 450℃. The mass loss rate was tested according to the following formula: mass loss rate (%) = [(initial mass - mass at 450℃)] / initial mass × 100%.

[0098] 3. Etching resistance test The initial film thickness of another set of hard masks was tested, and then CHF3 / CF4 gas was used as the etching gas (volume flow ratio of 1:1) for 90s of dry etching. After the etching was completed, the film thickness was measured again, and finally the etching rate (Å / s) was determined according to the following formula.

[0099] Etching rate = (Initial thickness of hard mask - Film thickness after etching) / Etching time 4. Membrane shrinkage rate test The hard mask composition was coated onto a silicon wafer using a spin coater for 120 seconds. The film thickness L0 of each sample before curing was tested (the film thickness of each sample before curing was set in the range of 3800~4200 Å). Then, the film was heat-treated at 320°C for 120 seconds. After cooling to room temperature, the film thickness L1 was tested again. The film shrinkage rate was determined according to the following formula: Film shrinkage rate (%) = [(L0-L1) / L0]×100%.

[0100] Table 2

[0101] As shown in Table 2, compared with Comparative Example 1, the hard masks formed by the quinoxaline dione polymers P1 to P10 of Examples 1 to 10 have lower mass loss rate, dry etching rate and film shrinkage rate at 450°C than those of Comparative Example 1. This indicates that polymers P1 to P10 can improve the heat resistance and etching resistance of the hard mask and reduce the film shrinkage rate after curing.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A quinoxaloline dione polymer, characterized in that, It has the structure shown in Equation 1: Formula 1, In Equation 1, n is an integer from 1 to 200; R1 and R2 may be the same or different, and each is independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, and the substituent is an alkyl group having 1 to 6 carbon atoms; R3 is hydrogen or an alkyl group having 1 to 6 carbon atoms; R4 is or , in," " indicates a connecting bond, where R5 is hydrogen, an alkyl group with 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group with 6 to 30 carbon atoms, and the substituent is a hydroxyl group; L is an arylene with 6 to 18 carbon atoms.

2. The quinoxaloline dione polymer according to claim 1, characterized in that, R4 is And R5 is selected from hydrogen, an alkyl group having 1 to 4 carbon atoms, or any one of the following groups: Preferably, R1 and R2 are each independently an alkyl group having 2 to 8 carbon atoms or an aryl group having 6 to 12 carbon atoms.

3. The quinoxaloline dione polymer according to claim 1 or 2, characterized in that, The weight-average molecular weight of the quinoxaline dione polymer is 3,000 to 30,000, and the molecular weight distribution index is 1.30 to 3.

50.

4. A method for preparing the quinoxaloline dione polymer according to any one of claims 1-3, characterized in that, The method includes: subjecting a quinoxaline dione monomer with the structure shown in Formula 2 to a polycondensation reaction with an aldehyde compound to form the quinoxaline dione polymer. Equation 2, In Formula 2, R1 and R2 may be the same or different, and each is independently hydrogen, an alkyl group with 1 to 10 carbon atoms, or a substituted or unsubstituted aryl group with 6 to 30 carbon atoms, and the substituent is an alkyl group with 1 to 6 carbon atoms; R3 is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

5. The method according to claim 4, characterized in that, The aldehyde compounds are selected from monobasic aliphatic aldehydes and / or monobasic aromatic aldehydes; Preferably, the monohydric aliphatic aldehyde is selected from at least one of formaldehyde, oligooxymethylene, acetaldehyde, propionaldehyde, and butyraldehyde; Preferably, the monovalent aromatic aldehyde is selected from at least one of benzaldehyde, naphthaldehyde, anthracene formaldehyde, pyrene formaldehyde, and p-hydroxybenzaldehyde; Preferably, the structure of the quinoxaloline dione monomer is as follows: 。 6. The method according to claim 4 or 5, characterized in that, The molar ratio of the quinoxaline dione monomer to the aldehyde compound is 1:(0.5~1.5), preferably 1:(0.7~0.95).

7. The method according to any one of claims 4-6, characterized in that, The polycondensation reaction was carried out in the presence of an acid catalyst; Preferably, the mass amount of the acid catalyst is 0.1% to 2.0% of the total mass of the quinoxalool dione monomer and the aldehyde compound; Preferably, the polycondensation reaction is carried out at a temperature of 60~200℃ and for a reaction time of 5~48h.

8. A hard mask composition, characterized in that, It comprises a solvent, a polymer, a catalyst, a crosslinking agent, a surfactant, and a plasticizer, wherein the polymer is a quinoxaline dione polymer as described in any one of claims 1-3.

9. The hard mask composition according to claim 8, characterized in that, Based on the total mass of the hard mask composition, the polymer has a mass content of 4% to 25%, the crosslinking agent has a mass content of 0.3% to 3%, the catalyst has a mass content of 0.005% to 0.1%, the surfactant has a mass content of 0.01% to 0.1%, and the plasticizer has a mass content of 0.4% to 2.5%.

10. A method for forming a pattern, characterized in that, Includes the following steps: Provide a material layer on the substrate; The hard mask composition of claim 8 or 9 is applied to the material layer to form a hard mask; A silicon-containing thin layer is formed on the hard mask; A photoresist resist layer is formed on the silicon-containing thin layer; The photoresist resist layer is exposed and developed to form a photoresist pattern; The silicon-containing thin layer and the hard mask are selectively removed using the photoresist pattern to expose a portion of the material layer; Etch the exposed portion of the material layer.

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