Alkaline compound and photoresist composition as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of photoresist, and particularly relates to an alkaline compound and a photoresist composition as well as a preparation method and application thereof. The photoresist composition contains a polymer, the alkaline compound, a solvent, a photoacid generator and a surfactant. The key point of the invention lies in providing an alkaline compound with a specific structure, the alkaline compound contains a purine group and an acid unstable group at the same time, and when the alkaline compound is used as a quencher of the photoresist composition, the contrast ratio of an exposed part and an unexposed part of the photoresist is remarkably improved, and the photoresist composition has a good application prospect. Therefore, the key size uniformity and the pattern focal depth of the photoresist composition are well improved, and the sensitivity of the photoresist can also be improved.

Description

Technical Field

[0001] This invention belongs to the field of photoresist technology, specifically relating to an alkaline compound and a photoresist composition, its preparation method, and its application. Background Technology

[0002] As logic devices continue to miniaturize, flash memory has seen the emergence of devices with a stacked layer structure known as 3D-NAND. As the number of stacked layers increases, the device capacity increases. However, as the number of stacked layers increases, the hard mask used for processing becomes thicker, and the photoresist film also becomes thicker. The photoresist used in 3D-NAND tends to be thicker.

[0003] As photoresist miniaturization progresses, it gradually approaches the diffraction limit of light, leading to a decrease in optical contrast. In the case of positive resist films, this decrease in optical contrast results in a reduction in the resolution and focal length of hole and trench patterns. For thicker photoresist films, existing films cannot meet the requirements for better critical dimension uniformity (CDU). To prevent the reduction in resist pattern resolution due to decreased optical contrast caused by size reduction, or to prevent the deterioration of critical dimension uniformity due to thicker resist films, quenchers can be considered for improvement. Currently used quenchers are mainly organic amine compounds, such as triethylamine and trioctylamine, which can prevent acid diffusion and improve dissolution contrast; however, further improvements are needed in improving the CDU and depth of focus (DOF) of the pattern. Summary of the Invention

[0004] The purpose of this invention is to address the problem that quenchers used in existing photoresists are ineffective in improving the CDU and DOF of patterns, and to provide a new alkaline compound that, when added to a photoresist composition, can significantly improve the CDU and DOF of photolithographic patterns, while also increasing the sensitivity of the photoresist.

[0005] In a first aspect, the present invention provides a basic compound. The basic compound has the structure shown in formula (1): Equation (1), In formula (1), R1 is an acid-unstable group, R2 is a C1-C4 alkylene group, and R3, R4 and R5 are each independently a hydrogen atom, a C1-C6 alkyl group, a C3-C6 cycloalkyl group or a halogen atom.

[0006] In a preferred embodiment, R1 is selected from any one or more of the following structures: , Where * indicates the position where group R1 is bonded to the oxygen atom corresponding to formula (1).

[0007] Secondly, the present invention provides a method for preparing the above-mentioned basic compound. The preparation method includes: a purine compound represented by formula (2) and a haloacid-sensitive compound represented by formula (3) undergoing a substitution reaction in the presence of a catalyst, and the resulting reaction product is the basic compound represented by formula (1); Equation (2), Equation (3), In formula (2), R3, R4 and R5 are each independently a hydrogen atom, a C1-C6 alkyl group, a C3-C6 cycloalkyl group or a halogen atom; In formula (3), X is a halogen atom, R1 is an acid-unstable group, and R2 is a C1~C4 alkylene group.

[0008] In a preferred embodiment, the molar ratio of the purine compound represented by formula (2) to the haloacid-sensitive compound represented by formula (3) is 1:(1~1.2).

[0009] In a preferred embodiment, the molar ratio of the catalyst to the purine compound is (1~1.2):1.

[0010] In a preferred embodiment, the catalyst is selected from at least one of sodium hydride mineral oil dispersion, sodium carbonate, and potassium carbonate.

[0011] In a preferred embodiment, the conditions for the substitution reaction include a temperature of 20-30°C and a time of 15-25 hours.

[0012] Thirdly, the present invention provides a photoresist composition. The photoresist composition contains a polymer, the above-mentioned basic compound, a solvent, a photoacid generator, and a surfactant; the polymer contains structural unit one shown in formula (4) and / or formula (5) and structural unit two having phenolic hydroxyl groups, wherein the structural unit two is selected from any one or more of the structures shown in formulas (6-1) to (6-4); Equation (4), Equation (5), , In formula (4), R6 is a hydrogen atom or a C1~C3 alkyl group, A1 is an acid-unstable group, and * indicates the bond position of structural unit one; In formula (5), A2 is an acid-unstable group, and * indicates the bond position of structural unit one; In equations (6-1) to (6-4), R 71 and R 72 Each is an independent hydrogen atom or a C1~C3 alkyl group, n is 1 or 2, and * indicates the bond position of structural unit two.

[0013] In a preferred embodiment, A1 and A2 are each independently selected from any one or more of the following structures:

[0014]

[0015] , In this context, * indicates the position where A1 or A2 is bonded to an oxygen atom.

[0016] In a preferred embodiment, the polymer further comprises structural unit three; the structural unit three is selected from any one or more of the structures shown in formulas (7-1) to (7-6); , In equations (7-1) to (7-6), R 81 ~R 86 Each is an independent hydrogen atom or a C1~C3 alkyl group, and * indicates the bond position of structural unit three.

[0017] In a preferred embodiment, the polymer has a weight-average molecular weight of 8000~15000 Da and a PDI of 1.6~2.5.

[0018] In a preferred embodiment, the molar ratio of structural unit 1, structural unit 2 and structural unit 3 in the polymer is 1:(0.5~2):(0~2).

[0019] In a preferred embodiment, the polymer content is 50-100 parts by weight, the alkaline compound content is 0.1-0.5 parts by weight, the solvent content is 500-1000 parts by weight, the photoacid generator content is 1-5 parts by weight, and the surfactant content is 0.1-0.5 parts by weight.

[0020] Fourthly, the present invention also provides the application of the above-mentioned photoresist composition in photolithography technology.

[0021] Beneficial effects: The key to this invention is providing an alkaline compound with a specific structure, which contains both purine groups and acid-unstable groups. When used as a quencher in a photoresist composition, on the one hand, due to the presence of acid-unstable groups, the polarity of the alkaline compound in the exposed portion changes due to acid decomposition, thereby further improving the contrast between the exposed and unexposed portions of the photoresist. On the other hand, due to the presence of highly polar purines within the molecule, it not only exhibits better stability during heating, effectively capturing the acid generated during exposure and inhibiting the excessive diffusion of acid to improve contrast, but also enhances the sensitivity of the photoresist, thereby significantly improving the critical dimension uniformity (CDU) and depth of focus (DOF) of the photoresist composition. Detailed Implementation

[0022] 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. Furthermore, unless otherwise specified, all embodiments and optional embodiments of the present invention can 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.

[0023] The basic compound provided by this invention has the structure shown in formula (1): Equation (1), In formula (1), R1 is an acid-unstable group, R2 is a C1-C4 alkylene group, and R3, R4, and R5 are each independently a hydrogen atom, a C1-C6 alkyl group, a C3-C6 cycloalkyl group, or a halogen atom. Specific examples of C1-C4 alkylene groups include, but are not limited to, any one of: -CH2-, -CH2CH2-, -CH(CH3)-, -CH2CH2CH2-, -CH(CH3)CH2-, -CH2CH2CH2CH2-, -CH(CH3)CH2CH2-, -CH2CH(CH3)CH2-, and -C(CH3)2CH2-. Specific examples of C1-C6 alkyl groups include, but are not limited to, any one of methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, sec-butyl, isobutyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl, 1,2-dimethylpropyl, 1-ethylpropyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, and 3,3-dimethylbutyl. Specific examples of C3-C6 cycloalkyl groups include, but are not limited to, any one of cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl. Specific examples of halogen atoms include, but are not limited to, any one of F, Cl, Br, and I.

[0024] In this invention, R1 is preferably selected from any one or more of the following structures:

[0025]

[0026] , Where * indicates the position where group R1 is bonded to the oxygen atom corresponding to formula (1).

[0027] The method for preparing the above-mentioned basic compound provided by the present invention includes: a purine compound represented by formula (2) and a haloacid-sensitive compound represented by formula (3) undergoing a substitution reaction in the presence of a catalyst, and the resulting reaction product is the basic compound represented by formula (1). In formula (2), R3, R4 and R5 are each independently a hydrogen atom, a C1-C6 alkyl group, a C3-C6 cycloalkyl group or a halogen atom. In formula (3), X is a halogen atom, R1 is an acid-unstable group, and R2 is a C1-C4 alkylene group. Specific examples of C1-C6 alkyl groups, C3-C6 cycloalkyl groups, halogen atoms, acid-unstable groups, and C1-C4 alkylene groups are as described above and will not be repeated here.

[0028] Equation (2), Equation (3).

[0029] In one specific embodiment, the preparation method of the basic compound may include the following steps: first, the purine compound shown in formula (2) is mixed and dissolved with an organic solvent, the resulting mixture I is then mixed with a catalyst, and the resulting mixture II is subjected to a substitution reaction with the haloacid-sensitive compound shown in formula (3), and the resulting reaction product is the basic compound shown in formula (1).

[0030] In the above-mentioned method for preparing the basic compound, the molar ratio of the purine compound represented by formula (2) to the haloacid-sensitive compound represented by formula (3) is preferably 1:(1~1.2), such as 1:1, 1:1.05, 1:1.1, 1:1.15, 1:1.2 or any value between them. The molar ratio of the catalyst to the purine compound is preferably (1~1.2):1, such as 1:1, 1.05:1, 1.1:1, 1.15:1, 1.2:1 or any value between them.

[0031] In the above-mentioned method for preparing alkaline compounds, the catalyst can be any compound capable of catalyzing the substitution reaction between the -NH- group of the purine compound shown in formula (2) and the halogen atom of the haloacid-sensitive compound shown in formula (3). Specific examples include, but are not limited to, at least one of sodium hydride mineral oil dispersion, sodium carbonate, and potassium carbonate, with sodium hydride mineral oil dispersion being particularly preferred. Specific examples of the organic solvent include, but are not limited to, at least one of N,N-dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide, and tetrahydrofuran.

[0032] In the above-mentioned method for preparing alkaline compounds, the mixing conditions preferably include: a temperature of -5 to 5°C, such as -5°C, -2°C, 0°C, 2°C, 5°C or any value between them; and a time of 5 to 15 min, such as 5 min, 8 min, 10 min, 12 min, 15 min or any value between them.

[0033] In the above-mentioned method for preparing the basic compound, the conditions for the substitution reaction preferably include: a temperature of 20~30℃, such as 20℃, 22℃, 25℃, 28℃, 30℃ or any value between them; and a time of 15~25h, such as 15h, 18h, 20h, 22h, 25h or any value between them.

[0034] The photoresist composition provided by the present invention contains a polymer, the above-mentioned alkaline compound (having the structure shown in formula (1)), a solvent, a photoacid generator, and a surfactant; the polymer contains structural unit one shown in formula (4) and / or formula (5) and structural unit two having a phenolic hydroxyl group, wherein the structural unit two is selected from any one or more of the structures shown in formulas (6-1) to (6-4). In formula (4), R6 is a hydrogen atom or a C1 to C3 alkyl group, A1 is an acid-instable group, and * indicates the bonding position of structural unit one with other structural units including structural unit one. In formula (5), A2 is an acid-instable group, and * indicates the bonding position of structural unit one with other structural units including structural unit one. In formulas (6-1) to (6-4), R 71 and R 72 Each unit is independently a hydrogen atom or a C1-C3 alkyl group, where n is 1 or 2, and * indicates the bond position between structural unit two and other structural units, including structural unit two. Specific examples of C1-C3 alkyl groups include, but are not limited to, any one of methyl, ethyl, n-propyl, and isopropyl. It should be noted that structural unit one and structural unit two can form a polymer through random copolymerization, block copolymerization, alternating copolymerization, and graft copolymerization, or any combination thereof.

[0035] Equation (4), Equation (5), .

[0036] In this invention, A1 and A2 are each preferably selected from any one or more of the following structures:

[0037]

[0038] , In this context, * indicates the position where A1 or A2 is bonded to an oxygen atom.

[0039] In this invention, the polymer preferably contains structural unit three; the structural unit three is preferably any one or more of the structures shown in formulas (7-1) to (7-6). In formulas (7-1) to (7-6), R 81 ~R 86 Each unit is independently a hydrogen atom or a C1-C3 alkyl group. * indicates the bond position between structural unit three and other structural units, including structural unit three. Specific examples of C1-C3 alkyl groups are as described above and will not be repeated here. It should be noted that structural units one, two, and three can form polymers through any one or more of the following methods: random copolymerization, block copolymerization, alternating copolymerization, and graft copolymerization.

[0040] .

[0041] In this invention, the weight-average molecular weight (Mw) of the polymer is preferably 8000~15000 Da, such as 8000 Da, 10000 Da, 12000 Da, 15000 Da or any value between them. The PDI of the polymer is preferably 1.6~2.5, such as 1.6, 1.8, 2.0, 2.2, 2.5 or any value between them.

[0042] In this invention, the molar ratio of structural unit one, structural unit two, and structural unit three in the polymer is preferably 1:(0.5~2):(0~2). Taking 1 mol of structural unit one in the polymer as a basis, the content of structural unit two is preferably 0.5~2 mol, such as 0.5 mol, 0.8 mol, 1 mol, 1.2 mol, 1.5 mol, 1.8 mol, 2 mol, or any value between them; the content of structural unit three is preferably 0~2 mol, such as 0 mol, 0.2 mol, 0.5 mol, 0.8 mol, 1 mol, 1.2 mol, 1.5 mol, 1.8 mol, 2 mol, or any value between them.

[0043] In this invention, the type of solvent is not particularly limited, as long as it is a solvent capable of dissolving polymers, basic compounds, photoacid generators, and surfactants. Specific examples include, but are not limited to, at least one of the following: cyclopentanone, cyclohexanone, 3-methoxybutanol, 1-methoxy-2-propanol, propylene glycol methyl ether (PGME), ethylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol methyl ether acetate (PGMEA), ethyl lactate, propylene glycol monoethyl ether acetate, butyl acetate, methyl 3-methoxypropionate, and ethyl 3-ethoxypropionate.

[0044] In this invention, the photoacid-generating agent can be selected from at least one of sulfonium salt compounds, iodide-based compounds, phosphonium salt-based compounds, and organic sulfonic acid compounds. Specific examples of the acid-generating agent include, but are not limited to: dodecylbenzenesulfonic acid, p-toluenesulfonic acid, phthalimide trifluoromethanesulfonate, phthalimide trifluoromethanesulfonate, dinitrobenzyltoluenesulfonate, dinitrobenzyltoluenesulfonate, n-decyl disulfone, naphthylimide trifluoromethanesulfonate, naphthylimide trifluoromethanesulfonate, diphenyliodotrifluoromethanesulfonate, diphenyliodoperfluorobutyl sulfonate, diphenyliodohexafluorophosphate, diphenyliodohexafluoroarsenate, diphenyliodohexafluoroantimonate, diphenyl-p-methoxyphenylsulfonium trifluoromethanesulfonate, diphenyl-p-toluenesulfonium trifluoromethanesulfonate, diphenyl The following is a list of at least one of the following: diphenyl-p-tert-butylphenylsulfonium trifluoromethanesulfonate, diphenyl-p-isobutylphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium trifluoromethanesulfonate, tri(p-tert-butylphenyl)sulfonium trifluoromethanesulfonate, diphenyl-p-methoxyphenylsulfonium perfluorobutyl sulfonate, diphenyl-p-tolylsulfonium perfluorobutyl sulfonate, diphenyl-p-tert-butylphenylsulfonium perfluorobutyl sulfonate, diphenyl-p-isobutylphenylsulfonium perfluorobutyl sulfonate, triphenylsulfonium perfluorobutyl sulfonate, triphenyl-p-tert-butylphenylsulfonium perfluorobutyl sulfonate, hexafluoroarsenate, hexafluoroarsenate, triphenylsulfonium hexafluoroantimonate, and dibutylnaphthylsulfonium trifluoromethanesulfonate.

[0045] In this invention, specific examples of the surfactants include, but are not limited to: polyoxyethylene alkyl ether surfactants such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene hexadecyl ether, and polyoxyethylene glycerol ether; polyoxyethylene alkyl aryl ether surfactants such as polyoxyethylene octylphenol ether and polyoxyethylene nonylphenol ether; and sorbitol monolaurate, sorbitol monopalmitate, sorbitol monostearate, sorbitol monooleate, sorbitol monooleate, and sorbitol trioleate. Surfactants of dehydrated sorbitol fatty acid esters such as sorbitol tristearate, surfactants of polyoxyethylene dehydrated sorbitol fatty acid esters such as polyoxyethylene-dehydrated sorbitol monolaurate, polyoxyethylene-dehydrated sorbitol monopalmitate, polyoxyethylene-dehydrated sorbitol monostearate, polyoxyethylene-dehydrated sorbitol trioleate, polyoxyethylene-dehydrated sorbitol tristearate, and fluorochemical surfactants such as FC-4430, FC-430, and FC-431 from 3M Company.

[0046] The present invention will be described in detail below through specific embodiments. These embodiments are intended to explain the invention and should not be construed as limiting it. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0047] Preparation Example 1: Preparation of Basic Compounds This preparation example illustrates the preparation process of a basic compound, and the specific process and synthetic route are shown below: Under a nitrogen atmosphere, 4.57 g (30 mmol) of octahydroxy-4,7-methylene-1H-indole-5-ol, 2.77 g (35 mmol) of pyridine, and 30 mL of tetrahydrofuran (THF) were added to a reaction vessel. The reaction solution was cooled to below 10 °C, and a solution consisting of 4.52 g (40 mmol) of chloroacetyl chloride and 30 mL of THF was slowly added dropwise. The reaction solution was then heated to 20 °C and stirred for 12 h. The resulting solid-liquid system was filtered, and the filtrate was collected. The filtrate was separated into products by column chromatography to obtain the haloacid-sensitive compound M1.

[0048] Under nitrogen atmosphere, 2.4 g (20 mmol) of purine was dissolved in 20 mL of N,N-dimethylformamide and cooled to 0 °C. Then, 0.88 g (22 mmol) of 60% sodium hydride mineral oil dispersion was added, and the mixture was stirred at 0 °C for 10 min. The temperature was then raised to 25 °C, and 5.34 g (22 mmol) of haloacid-sensitive compound M1 was added dropwise. The mixture was stirred at 25 °C for 20 h. The reaction solution was filtered to remove inorganic salts. The solvent was then evaporated, and the remaining solid was dissolved in ethyl acetate, washed with saturated ammonium chloride solution and brine, dried over magnesium sulfate, and the solvent was evaporated again. The remaining solid was purified by rapid column chromatography to obtain a yellow oily product, which was the basic compound Q1.

[0049]

[0050] Preparation Example 2: Preparation of Basic Compounds This preparation example illustrates the preparation process of a basic compound, and the specific process and synthetic route are shown below: Under a nitrogen atmosphere, 3.37 g (30 mmol) of bicyclo[2.2.1]-2-heptanol, 2.77 g (35 mmol) of pyridine, and 30 mL of tetrahydrofuran (THF) were added to a reaction vessel. The reaction solution was cooled to below 10 °C, and a solution consisting of 4.52 g (40 mmol) of chloroacetyl chloride and 30 mL of THF was slowly added dropwise. The reaction solution was then heated to 20 °C and stirred for 12 h. The resulting solid-liquid system was filtered, and the filtrate was collected. The filtrate was separated into products by column chromatography to obtain the haloacid-sensitive compound M2.

[0051] Under nitrogen atmosphere, 2.68 g (20 mmol) of 2-methyl-1H-purine was dissolved in 20 mL of N,N-dimethylformamide and cooled to 0 °C. Then, 0.88 g (22 mmol) of 60% sodium hydride mineral oil dispersion was added, and the mixture was stirred at 0 °C for 10 min. The temperature was then raised to 25 °C, and 4.46 g (22 mmol) of haloacid-sensitive compound M2 was added dropwise. The mixture was stirred at 25 °C for 20 h. The reaction solution was filtered to remove inorganic salts. The solvent was then evaporated, and the remaining solid was dissolved in ethyl acetate, washed with saturated ammonium chloride solution and brine, dried over magnesium sulfate, and the solvent was evaporated again. The remaining solid was purified by rapid column chromatography to obtain a yellow oily product, which was the basic compound Q2.

[0052]

[0053] Preparation Example 3: Preparation of Basic Compounds This preparation example illustrates the preparation process of a basic compound, and the specific process and synthetic route are shown below: The basic compound was prepared according to the method of Preparation Example 1, except that the same number of 1-methylcyclopentanol was used instead of 5-methyloctahydro-1H-4,7-methylene-indene-5-ol, and the same number of 2-chloro-9H-purine was used instead of purine. All other conditions were the same as in Preparation Example 1. A yellow oily product was obtained, which is the basic compound Q3.

[0054]

[0055] Preparation Example 4: Preparation of Basic Compounds This preparation example illustrates the preparation process of a basic compound, and the specific process and synthetic route are shown below: The basic compound was prepared according to the method of Preparation Example 1, except that the same number of 7-oxabicyclo[2.2.1]heptane-2-ol was used instead of 5-methyloctahydro-1H-4,7-methylene-indene-5-ol, and the same number of 6-chloro-8-cyclopentyl-9H-purine was used instead of purine. All other conditions were the same as in Preparation Example 1. A yellow oily product was obtained, which is the basic compound Q4.

[0056]

[0057] Synthesis Example 1: Polymer Synthesis This synthetic example illustrates the preparation process of a polymer, and the specific process is shown below: At room temperature, 7.93 g (45 mmol) of tert-butoxystyrene, 6.60 g (55 mmol) of p-hydroxystyrene, and 0.16 g (1 mmol) of azobisisobutyronitrile (azobisisobutyronitrile) initiator were sequentially added to 30 g of tetrahydrofuran solvent. The reaction system was heated to 70 °C for 6 h under a nitrogen atmosphere. After cooling to room temperature, 500 g of methanol was added dropwise, and the mixture was stirred to precipitate the polymer. The polymer was then repeatedly washed with hexane, separated, and dried. The resulting polymer P1 contained the structural units shown below, and the molar percentages of each structural unit are shown below. The Mw of polymer P1 was determined to be 10420 Da, and the PDI was 1.8.

[0058]

[0059] Synthesis Example 2: Polymer Synthesis This synthetic example illustrates the preparation process of a polymer, and the specific process is shown below: At room temperature, 6.87 g (35 mmol) of 1-isopropylcyclopentyl methacrylate, 6.85 g (30 mmol) of 4-hydroxynaphthalene-1-methacrylate, 5.96 g (35 mmol) of 2-oxotetrahydrofuran-3-yl methacrylate, and 0.16 g (1 mmol) of azobisisobutyronitrile (AIB) initiator were sequentially added to 30 g of tetrahydrofuran solvent. The reaction system was heated to 70 °C for 6 h under a nitrogen atmosphere. After cooling to room temperature, 500 g of methanol was added dropwise, and the mixture was stirred to precipitate the polymer. The polymer was then repeatedly washed with hexane, separated, and dried. The resulting polymer P2 contained the structural units shown below, and the molar percentages of each structural unit are shown below. The Mw of polymer P2 was determined to be 11500 Da, and the PDI was 1.6.

[0060]

[0061] Synthesis Example 3: Polymer Synthesis This synthetic example illustrates the preparation process of a polymer, and the specific process is shown below: At room temperature, 7.29 g (35 mmol) of 2-ethylnorborneol methacrylate, 5.11 g (30 mmol) of 6-vinyl-2-naphthol, 5.46 g (35 mmol) of 2-tetrahydrofuranyl methacrylate, and 0.16 g (1 mmol) of azobisisobutyronitrile (AIB) initiator were sequentially added to 30 g of tetrahydrofuran solvent. The reaction system was heated to 70 °C for 6 h under a nitrogen atmosphere. After cooling to room temperature, 500 g of methanol was added dropwise, and the mixture was stirred to precipitate the polymer. The polymer was then repeatedly washed with hexane, separated, and dried. The resulting polymer P3 contained the structural units shown below, and the molar percentages of each structural unit are shown below. The Mw of polymer P3 was determined to be 9500 Da, and the PDI was 1.9.

[0062]

[0063] Synthesis Example 4: Polymer Synthesis This synthetic example illustrates the preparation process of a polymer, and the specific process is shown below: At room temperature, 5.05 g (30 mmol) of 1-methylcyclopentyl methacrylate, 2.67 g (15 mmol) of 4-hydroxyphenyl methacrylate, 12.22 g (55 mmol) of 2-oxohexahydro-2H-3,5-methylenecyclopenta[b]furan-6-yl methacrylate, and 0.16 g (1 mmol) of azobisisobutyronitrile (AIB) initiator were sequentially added to 30 g of tetrahydrofuran solvent. The reaction system was heated to 70 °C for 6 h under a nitrogen atmosphere. After cooling to room temperature, 500 g of methanol was added dropwise, and the mixture was stirred to precipitate the polymer. The polymer was then repeatedly washed with hexane, separated, and dried. The resulting polymer P4 contained the structural units shown below, and the molar percentages of each structural unit are shown below. The Mw of polymer P4 was 12000 Da, and the PDI was 1.3.

[0064]

[0065] Synthesis Example 5: Polymer Synthesis This synthetic example illustrates the preparation process of a polymer, and the specific process is shown below: At room temperature, 5.05 g (30 mmol) of 1-methylcyclopentyl methacrylate, 9.80 g (55 mmol) of 4-hydroxyphenyl methacrylate, 3.33 g (15 mmol) of 2-oxohexahydro-2H-3,5-methylenecyclopenta[b]furan-6-yl methacrylate, and 0.16 g (1 mmol) of azobisisobutyronitrile (AIB) initiator were sequentially added to 30 g of tetrahydrofuran solvent. The reaction system was heated to 70 °C for 6 h under a nitrogen atmosphere. After cooling to room temperature, 500 g of methanol was added dropwise, and the mixture was stirred to precipitate the polymer. The polymer was then repeatedly washed with hexane, separated, and dried. The obtained polymer P5 contained the structural units shown below, and the molar percentages of each structural unit are shown below. The Mw of polymer P5 was 11000 Da, and the PDI was 1.4.

[0066]

[0067] Examples 1-8 and Comparative Examples 1-3 80 parts by weight of polymer, 0.3 parts by weight of alkaline compound, 2 parts by weight of photoacid generator, and 0.1 parts by weight of surfactant were added to 800 parts by weight of propylene glycol methyl ether acetate (PGMEA) and stirred until dissolved. The resulting solution was filtered through a 0.5 μm pore size filter to obtain a photoresist composition. The specific types of polymer and alkaline compound (quencher) are shown in Table 1. The photoacid generator PAG-X (structure shown below) and the surfactant FC4430 purchased from 3M were used.

[0068] PAG-X Table 1

[0069] Test case The photoresist compositions prepared in the above examples and comparative examples were used to form photolithographic patterns and their sensitivity, CDU, and DOF were evaluated. The results are shown in Table 2.

[0070] (1) Method for forming hole pattern: The organic anti-reflective film composition "HZBB-083" (manufactured by Fujian Hongguang) was coated onto a silicon wafer using a spin coater to form an organic anti-reflective film with a thickness of 83nm. Then, the photoresist compositions obtained in the above examples and comparative examples were coated onto the anti-reflective film using a spin coater, and baked on a heat carrier plate at 130°C for 60s to dry it, thereby forming a photoresist film with a thickness of 200nm on the anti-reflective film.

[0071] The silicon wafer on which the photoresist film is formed is exposed by KrF laser (using a design pattern with a hole diameter of 50nm and a pattern period of 100nm). After photolithography, it is baked on a heat carrier plate at 110℃ for 90s, and finally developed in 2.38% TMAH developer for 60s. It is then quickly removed and rinsed in pure water to obtain the photoresist pattern.

[0072] (2) Sensitivity evaluation: The aperture pattern formed by the above method was observed using a CD-SEM (CG6300, Hitachi High-Tech). The optimal dose (Eop) was the exposure dose (mJ / cm) at 100 nm to provide an aperture diameter of 50 nm. 2 This value is used as an index of photosensitivity. The smaller the value, the higher the sensitivity, i.e., the higher the sensitivity.

[0073] (3) Evaluation of critical dimension uniformity (CDU): The hole pattern formed by the above method was observed under CD-SEM and the diameter of 125 holes was measured. The three times the standard deviation (σ) (3σ) was calculated and the three times the standard deviation (σ) was recorded as CDU. The smaller this value is, the better the dimensional uniformity of the hole pattern.

[0074] (4) Depth of focus (DOF) evaluation: The aperture size at the optimal dose is measured under CD-SEM, and the focal range formed within the range of 50 nm ± 5 nm is used as the depth of focus. The larger the value of the depth of focus, the wider the focal depth.

[0075] Table 2

[0076] As shown in Table 1, compared with Comparative Examples 1-3, Examples 1-8, due to the use of the alkaline compound provided by the present invention as a quencher, resulted in photoresist compositions exhibiting significantly improved critical dimension uniformity (CDU), greater depth of focus (DOF), and higher sensitivity.

[0077] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. An alkaline compound, characterized in that, The basic compound has a structure as shown in formula (1): formula (1), In formula (1), R1 is an acid-labile group, R2 is C1-C4 alkylene, and R3, R4 and R5 are each independently a hydrogen atom, C1-C6 alkyl, C3-C6 cycloalkyl or halogen atom.

2. The basic compound according to claim 1, characterized by R1 is selected from any one or several of the following structures: ， Wherein, * indicates the position of the group R1 bonded with the corresponding oxygen atom in formula (1).

3. Process for the preparation of a basic compound according to claim 1 or 2, characterized in that, The preparation method comprises: a substitution reaction of a purine compound shown in formula (2) and a halogenated acid-sensitive compound shown in formula (3) in the presence of a catalyst, and the obtained reaction product is the basic compound shown in formula (1); formula (2), formula (3), In formula (2), R3, R4 and R5 are each independently a hydrogen atom, C1-C6 alkyl, C3-C6 cycloalkyl or halogen atom; In formula (3), X is a halogen atom, R1 is an acid-labile group, and R2 is C1-C4 alkylene.

4. The method of claim 3, wherein the basic compound is prepared by the process comprising: The molar ratio of the purine compound shown in formula (2) to the halogenated acid-sensitive compound shown in formula (3) is 1:(1-1.2); Preferably, the molar ratio of the catalyst to the purine compound is (1-1.2):1; Preferably, the catalyst is selected from at least one of sodium hydride mineral oil dispersion, sodium carbonate and potassium carbonate; Preferably, the conditions of the substitution reaction include: temperature of 20-30℃, and time of 15-25h.

5. A photoresist composition characterized by comprising: The photoresist composition contains a polymer, the basic compound shown in claim 1 or 2, a solvent, a photo-acid generator and a surfactant; the polymer contains structural unit one shown in formula (4) and / or formula (5) and structural unit two with phenolic hydroxyl, wherein the structural unit two is selected from any one or several of the structures shown in formula (6-1) to formula (6-4); formula (4), formula (5), ， In formula (4), R6 is a hydrogen atom or C1-C3 alkyl, A1 is an acid-labile group, and * indicates the bonding position of structural unit one; In formula (5), A2 is an acid-labile group, and * indicates the bonding position of structural unit one; In formula (6-1) to formula (6-4), R 71 and R 72 each independently is a hydrogen atom or a C1-C3 alkyl group, n is 1 or 2, and * indicates the bonding position of the structural unit II.

6. The photoresist composition of claim 5, wherein A1 and A2 are each independently selected from any one or several of the following structures: ， Wherein, * indicates the bonding position of A1 or A2 with the oxygen atom.

7. The photoresist composition of claim 5, wherein The polymer further contains structural unit three; the structural unit three is selected from any one or several of the structures shown in formula (7-1) to formula (7-6); ， In formulae (7-1) to (7-6), R 81 ~R 86 each independently is a hydrogen atom or a C1-C3 alkyl group, and * indicates the bonding position of the structural unit III.

8. The photoresist composition of claim 7, wherein The weight average molecular weight of the polymer is 8000-15000 Da, and the PDI is 1.6-2.5; Preferably, the molar ratio of structural unit one, structural unit two and structural unit three in the polymer is 1:(0.5-2):(0-2).

9. The photoresist composition of claim 5, wherein The content of the polymer is 50-100 parts by weight, the content of the basic compound is 0.1-0.5 parts by weight, the content of the solvent is 500-1000 parts by weight, the content of the photo-acid generator is 1-5 parts by weight, and the content of the surfactant is 0.1-0.5 parts by weight.

10. Use of the photoresist composition according to any one of claims 5-9 in photolithography.

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