A crosslinking agent and its preparation method, and a photoresist.

Abstract

This application provides a crosslinking agent and its preparation method, as well as a photoresist, belonging to the field of photolithography technology. The photoresist comprises a solute and a first solvent, wherein the solute comprises 70wt%–95wt% alkali-soluble resin, 1wt%–30wt% photoacid-generating agent, 0.1wt%–15wt% acid quencher, and 5wt%–20wt% of the aforementioned crosslinking agent, and the mass of the first solvent is 1 to 10 times the mass of the alkali-soluble resin. The crosslinking agent of this application can be added to the photoresist, making the crosslinking reaction of the photoresist matrix resin more uniform, reducing or avoiding morphological defects caused by excessively large local molecular weights, resulting in more vertical edges and larger windows in the obtained pattern lines.

Description

Technical Field

[0001] This application relates to the field of photolithography technology, and more specifically, to a crosslinking agent and its preparation method, and a photoresist. Background Technology

[0002] Photoresist is one of the key materials for micro-patterning in microelectronics technology. In particular, the development of large-scale and very large-scale integrated circuits in recent years has greatly promoted the research, development and application of photoresist.

[0003] Negative photoresists based on the principle of photochemical amplification contain photoacid-generating agents and crosslinking agents. After exposure, they release acid, and the photoacid-generating agents catalyze the interaction between the crosslinking agents and the resin, leading to crosslinking. The crosslinked resin, unlike the resin in the unexposed areas, becomes insoluble in the developer, thus leaving a pattern on the substrate material opposite to that of the photomask. The speed and uniformity of the crosslinking reaction between the resin and the crosslinking agent have a decisive impact on the performance of the photoresist.

[0004] Photoresists are designed for specific exposure wavelengths. G-line 436nm, I-line 365nm, KrF 248nm, and ArF 193nm are currently the mainstream exposure light source wavelengths in the industry. During exposure, the light intensity distribution in the photoresist film exhibits a vertical gradient, resulting in a vertically uneven photon concentration. This leads to a vertically uneven chemical reaction, meaning that the cross-linking reaction between the resin and the cross-linking agent varies at different locations within the pattern. If the varying degrees of cross-linking result in significant local molecular weight differences, the produced pattern is highly susceptible to defects. Summary of the Invention

[0005] This application provides a crosslinking agent and its preparation method, as well as a photoresist, which can improve the morphological defects of the obtained pattern.

[0006] The embodiments of this application are implemented as follows:

[0007] In a first aspect, this application provides a crosslinking agent with the following structural formula:

[0008]

[0009] Among them, R1, R2, R3, R4, R5, and R6 are each independently selected from H and C. 1～10 Saturated or unsaturated alkyl groups, C 1～10 Saturated or unsaturated cycloalkyl groups or -R9-OR 10 .

[0010] R7 is selected from C 1～10 alkyl.

[0011] R8 is selected from H or C. 1～20 alkyl.

[0012] R9 is selected from C 1～10 alkyl.

[0013] R 10 Selected from H or C 1～20 alkyl.

[0014] Any two of R1, R2, R3, R4, R5 and R6 are selected from at least one of the first group and the second group.

[0015] The structural formula of the first group is:

[0016] The structural formula of the second group is -R9-OR 10 And R 10 Not H.

[0017] In the above technical solution, the crosslinking agent of this application can be added to the photoresist, making the crosslinking reaction of the base resin of the photoresist more uniform, reducing or avoiding morphological defects caused by excessively large local molecular weight, and resulting in more vertical edges of the pattern lines and larger windows.

[0018] In conjunction with the first aspect, in a first possible example of the first aspect of this application, the aforementioned R 10 Selected from C 8～16 alkyl.

[0019] In the above examples, the crosslinking agent of this application does not release large amounts of low-boiling-point alcohols during the crosslinking reaction, meaning it causes virtually no environmental pollution and is a green and environmentally friendly crosslinking agent. Furthermore, the volatilization of low-boiling-point alcohols does not adversely affect the morphology of the photoresist. Moreover, the non-volatile small-molecule alcohols generated during the crosslinking reaction can alleviate stress problems between the substrate and photoresist caused by film hardening, reducing the risk of photoresist layer deformation and cracking.

[0020] In conjunction with the first aspect, in a second possible example of the first aspect of this application, any 2 to 4 of the above-mentioned R1, R2, R3, R4, R5 and R6 are selected from at least one of the first group and the second group.

[0021] In conjunction with the first aspect, in a third possible example of the first aspect of this application, both R7 and R9 are selected from CH2.

[0022] In conjunction with the first aspect, in the fourth possible example of the first aspect of this application, both R4 and R5 are selected from H.

[0023] In a second aspect, this application provides a method for preparing the crosslinking agent of the above embodiments, comprising: reacting hydroxyalkyl melamine and reactants with an acid catalytic reaction to obtain an intermediate, and then neutralizing the intermediate;

[0024] The structural formula of hydroxyalkyl melamine is as follows:

[0025]

[0026] Among them, R 11 R 12 R 13 R 14 R 15 and R 16 Each is independently selected from H or -R 17 -OH.

[0027] R 17 Selected from C 1～10 alkyl.

[0028] R 11 R 12 R 13 R 14 R 15 and R 16 Any two of them are selected from -R 17 -OH.

[0029] The reactants include at least one of alkylphenol compounds and alcohol compounds.

[0030] The structural formulas of alkylphenol compounds are as follows:

[0031]

[0032] Among them, R 18 R 19 Each is independently selected from H and -R 20 .

[0033] R 20 Selected from C 1-20 Saturated or unsaturated alkyl groups.

[0034] R 18 R 19 At least one of them is selected from -R 20 .

[0035] The structural formulas of alcohols are as follows:

[0036]

[0037] n is 0 to 19.

[0038] In the above technical solutions, the preparation method of the crosslinking agent of this application is simple and easy to realize industrial production.

[0039] In conjunction with the second aspect, in the first possible example of the second aspect of this application, the above-mentioned acidic catalytic reaction temperature is 50℃~150℃, and the reaction time is 0.4h~12h.

[0040] In the above example, the preparation method of the crosslinking agent in this application is safe and reliable in terms of reaction conditions and temperature.

[0041] In conjunction with the second aspect, in a second possible example of the second aspect of this application, the molar ratio of the above-mentioned hydroxyalkyl melamine to the reactants is 1:2 to 1:5.

[0042] In conjunction with the second aspect, in a third possible example of the second aspect of this application, the aforementioned alkylphenols include any one or more of cresol, xylenol, ethylphenol, propylphenol, tert-butylphenol, pentylphenol, hepta-phenol, octylphenol, 2,4-di-tert-butylphenol, nonylphenol, decylphenol, dodecylphenol, tetradecylphenol, hexadecylphenol, octadecylphenol, and cashew phenol.

[0043] Alcohols include any one or more of methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, deca-ol, dodeca-ol, tetradecylol, hexadecylol, octadeca-ol, and eicosylol.

[0044] In a third aspect, this application provides a photoresist comprising: a solute and a first solvent, wherein the solute comprises 70wt% to 95wt% of an alkali-soluble resin, 1wt% to 30wt% of a photoacid-generating agent, 0.1wt% to 15wt% of an acid quencher, and 5wt% to 20wt% of the aforementioned crosslinking agent, and the mass of the first solvent is 1 to 10 times the mass of the alkali-soluble resin.

[0045] Optionally, the alkali-soluble resin includes any one or more of poly(p-hydroxystyrene) resin, polystyrene resin, poly(p-hydroxystyrene) resin, and linear phenolic resin.

[0046] Optionally, the photoacid generator includes any one or more of iodonium salts, thiodonium salts, and heterocyclic acid generators.

[0047] Optionally, the acid quencher may include a basic organic compound.

[0048] Optionally, basic organic compounds include tertiary ammonium compounds and / or quaternary ammonium compounds.

[0049] Optionally, the first solvent includes any one or more of 1,2-propanediol methyl ether acetate, ethyl lactate, and ethyl acetate.

[0050] In the above technical solution, the photoresist of this application has fewer or no morphological defects during use, the edges of the pattern lines are more vertical, and the window is larger. Attached Figure Description

[0051] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0052] Figure 1 This is a schematic diagram showing the first type of defect in the pattern after photoresist development;

[0053] Figure 2 A schematic diagram showing the second type of defect in the pattern after photoresist development;

[0054] Figure 3 This is a schematic diagram of the pattern formed after photoresist development in Embodiment 1 of this application at a focal length of -0.3 to 0.3.

[0055] Figure 4 This is a schematic diagram of the pattern formed after photoresist development in Embodiment 2 of this application at a focal length of -0.3 to 0.3.

[0056] Figure 5 This is a schematic diagram of the pattern formed after photoresist development in Embodiment 3 of this application at a focal length of -0.3 to 0.3.

[0057] Figure 6 This is a schematic diagram of the pattern formed after photoresist development in Embodiment 4 of this application at a focal length of -0.3 to 0.3.

[0058] Figure 7 This is a schematic diagram of the pattern formed after photoresist development in Embodiment 5 of this application at a focal length of -0.3 to 0.3.

[0059] Figure 8 This is a schematic diagram of the pattern formed after photoresist development in Comparative Example 1 of this application at a focal length of -0.3 to 0.3.

[0060] Figure 9 This is a schematic diagram of the pattern formed after the photoresist of Embodiment 1 of this application is developed at a film thickness of 20 μm;

[0061] Figure 10 This is a schematic diagram showing the pattern formed by developing the photoresist in Comparative Example 1 of this application at a film thickness of 20 μm. Detailed Implementation

[0062] The embodiments of this application will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of this application. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0063] Photoresist, also known as photoresist, is a thin film etchant material whose solubility changes when exposed to ultraviolet light, electron beams, ion beams, X-rays, etc. It can be widely used in the processing of micro-patterns, such as the manufacture of integrated circuits, flat panel displays, and semiconductor discrete devices.

[0064] The inventors noted that during light exposure, the light intensity distribution in the film exhibits a longitudinal gradient, resulting in longitudinally uneven photon concentration. This leads to longitudinally uneven chemical reactions, meaning that the cross-linking reaction between the resin and cross-linking agent varies at different locations within the pattern. If the varying degrees of cross-linking result in significant local molecular weight differences, the produced pattern is highly susceptible to defects. For example, incomplete development at the bottom or top of trenches or insufficient verticality of the sidewalls of the 3D pattern can lead to tailing at the bottom. Figure 1 and 2 As shown, Figure 1 The morphological defect shown is that the 200nm space is not fully opened and there is adhesion. Figure 2 The morphological defect shown is a trailing effect at the bottom of the 200nm space morphology.

[0065] In order to improve the defects in the pattern morphology of photoresist, the applicant found that the pattern morphology can be improved by increasing the uniformity of the resin crosslinking reaction at different locations in the photoresist.

[0066] Based on the above considerations, in order to improve the pattern morphology by increasing the uniformity of the resin crosslinking reaction at different locations in the photoresist, the inventors, after in-depth research, designed a crosslinking agent that can be added to the photoresist to make the crosslinking reaction of the base resin of the photoresist more uniform, reduce or avoid morphology defects caused by excessively large local molecular weights, and obtain pattern lines with more vertical edges and larger windows.

[0067] This application provides a photoresist with the following structural formula:

[0068]

[0069] Among them, R1, R2, R3, R4, R5, and R6 are each independently selected from H and C. 1～10 Saturated or unsaturated alkyl groups, C1～10 Saturated or unsaturated cycloalkyl groups or -R9-OR 10 .

[0070] R7 is selected from C 1～10 alkyl.

[0071] R8 is selected from H or C. 1～20 alkyl.

[0072] R9 is selected from C 1～10 alkyl.

[0073] R 10 Selected from H or C 1～20 alkyl.

[0074] Any two of R1, R2, R3, R4, R5 and R6 are selected from at least one of the first group and the second group.

[0075] The structural formula of the first group is:

[0076] The structural formula of the second group is -R9-OR 10 And R 10 Not H.

[0077] As an example, any two of R1, R2, R3, R4, R5, and R6 can be R1 and R2, R1 and R3, R1 and R4, R1 and R5, R1 and R6, R2 and R3, R2 and R4, R2 and R5, R2 and R6, R3 and R4, R3 and R5, R3 and R6, R4 and R5, R4 and R6, R5 and R6, R1, R2 and R3, R1, R2 and R4, R 1. R2 and R5, R1, R2 and R6, R1, R3 and R4, R1, R3 and R5, R1, R3 and R6, R2, R3 and R6, R3, R4 and R6, R4, R5 and R6, R1, R2, R3 and R4, R2, R3, R5 and R6, R1, R2, R3, R4 and R5, R1, R2, R3, R4 and R6, R1, R2, R3, R4, R5 and R6.

[0078] As an example, any two of R1, R2, R3, R4, R5 and R6 may all be selected from the first group, or all be selected from the second group, or be partially selected from the first group and partially selected from the second group.

[0079] Optionally, any 2 to 4 of R1, R2, R3, R4, R5 and R6 are selected from at least one of the first group and the second group.

[0080] Optionally, R 10 Selected from C 8～16 alkyl.

[0081] The crosslinking agent of this application releases virtually no low-boiling-point alcohols during the crosslinking reaction, meaning it causes minimal environmental pollution and is therefore a green and environmentally friendly crosslinking agent. Furthermore, the volatilization of low-boiling-point alcohols does not adversely affect the morphology of the photoresist. Moreover, the non-volatile small-molecule alcohols generated during the crosslinking reaction can alleviate stress problems between the substrate and photoresist caused by film hardening, reducing the risk of photoresist layer deformation and cracking.

[0082] Optionally, both R7 and R9 are selected from CH2.

[0083] Optionally, both R4 and R5 are selected from H.

[0084] This application also provides a method for preparing the crosslinking agent of the above embodiments, which includes: adding reactants and a second solvent to a reaction flask equipped with a stirring device, a thermometer and a reflux condenser; heating to completely dissolve the reactants in the second solvent to obtain a first mixture; adding an acidic catalyst to the first mixture to obtain a second mixture; slowly adding hydroxyalkyl melamine to the second mixture; controlling the reaction temperature at 50°C to 150°C; reacting under reflux for 0.4 h to 12 h to obtain an intermediate; neutralizing the intermediate and removing the second solvent under reduced pressure and vacuum; discharging the material to obtain the crosslinking agent.

[0085] The reactants include at least one of alkylphenol compounds and alcohol compounds.

[0086] It should be noted that the types of reactants and the amounts of alkylphenol and alcohol compounds used need to be determined based on the designed crosslinking agent.

[0087] The structural formulas of alkylphenol compounds are as follows:

[0088]

[0089] Among them, R 18 R 19 Each is independently selected from H and -R 20 .

[0090] R 20 Selected from C 1-20 Saturated or unsaturated alkyl groups.

[0091] R 18 R 19 At least one of them is selected from -R 20 .

[0092] Optionally, alkylphenols include any one or more of cresol, xylenol, ethylphenol, propylphenol, tert-butylphenol, pentylphenol, hepta-phenol, octylphenol, 2,4-di-tert-butylphenol, nonylphenol, decylphenol, dodecylphenol, tetradecylphenol, hexadecylphenol, octadecylphenol, and cashew phenol.

[0093] The structural formulas of alcohols are as follows:

[0094]

[0095] n is 0 to 19.

[0096] Optionally, the alcohol compounds include any one or more of methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, deca-ol, dodeca-ol, tetradecylol, hexadecylol, octadeca-ol, and eicosylol.

[0097] The second solvent includes any one or more of toluene, xylene, petroleum ether, chloroform, ethyl acetate, and dichloromethane.

[0098] The mass ratio of the second solvent to the reactants is 0.2 to 4:1.

[0099] Acidic catalysts include organic acid catalysts and / or inorganic acid catalysts.

[0100] Optionally, the organic acid catalyst includes any one or more of trifluoroacetic acid, trichloroacetic acid, dodecylbenzenesulfonic acid, benzenesulfonic acid, acetic acid, and oxalic acid.

[0101] Optionally, the inorganic acid catalyst includes any one or more of hydrochloric acid, sulfuric acid, sulfurous acid, phosphoric acid, and nitric acid.

[0102] The structural formula of hydroxyalkyl melamine is as follows:

[0103]

[0104] Among them, R 11 R 12 R 13 R 14 R 15 and R 16 Each is independently selected from H or -R 17 -OH.

[0105] R 17 Selected from C 1～10 alkyl.

[0106] R 11 R 12 R 13 R 14 R 15 and R 16Any two of them are selected from -R 17 -OH.

[0107] The molar ratio of hydroxyalkyl melamine to reactants is 1:2 to 1:5.

[0108] As an example, the molar ratio of hydroxyalkyl melamine to reactants can be 1:2, 1:3, 1:4, or 1:5.

[0109] As an example, the reaction temperature can be 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, or 150°C.

[0110] As an example, the reaction time can be 0.4h, 0.5h, 0.8h, 1h, 2h, 5h, 8h, 10h or 12h.

[0111] The temperature for vacuuming is 120℃~230℃.

[0112] As an example, the temperature for vacuuming can be 120°C, 150°C, 170°C, 190°C, 200°C, 210°C, or 230°C.

[0113] The vacuuming time is 20 to 40 minutes.

[0114] As an example, the decompression and vacuuming time can be 20 minutes, 30 minutes, or 40 minutes.

[0115] This application also provides a photoresist comprising: a solute and a first solvent, wherein the solute comprises 70wt% to 95wt% of an alkali-soluble resin, 1wt% to 30wt% of a photoacid-generating agent, 0.1wt% to 15wt% of an acid quencher, and 5wt% to 20wt% of the aforementioned crosslinking agent, and the mass of the first solvent is 1 to 10 times the mass of the alkali-soluble resin.

[0116] Optionally, the alkali-soluble resin includes any one or more of poly(p-hydroxystyrene) resin, polystyrene resin, poly(p-hydroxystyrene) resin, and linear phenolic resin.

[0117] Optionally, the photoacid generator includes any one or more of iodonium salts, thiodonium salts, and heterocyclic acid generators.

[0118] Optionally, the acid quencher may include a basic organic compound.

[0119] Optionally, basic organic compounds include tertiary ammonium compounds and / or quaternary ammonium compounds.

[0120] Optionally, the acid quencher includes any one or more of triethanolamine, trioctylamine, tributylamine, and trimethoxyethoxymethoxyethylamine.

[0121] Optionally, the first solvent includes any one or more of 1,2-propanediol methyl ether acetate, ethyl lactate, and ethyl acetate.

[0122] The following describes in further detail a crosslinking agent and its preparation method, as well as a photoresist, based on embodiments of the present application.

[0123] Example 1

[0124] This application provides a crosslinking agent and its preparation method, as well as a photoresist, which includes the following steps:

[0125] 2.0 mol tetradecylphenol, 2.0 mol n-octanol, and 100 mL toluene were added to a 500 mL round-bottom flask equipped with a stirrer, thermometer, and reflux condenser. The mixture was heated and stirred until the tetradecylphenol and n-octanol were completely dissolved in the toluene to obtain a first mixture. 0.5 g dodecylbenzenesulfonic acid was added to the first mixture to obtain a second mixture. 1.0 mol tetrahydroxymethyl melamine was slowly added to the second mixture. The reaction temperature was controlled at 70 °C, and the mixture was reacted under reflux for 4.5 h to obtain an intermediate. The intermediate was neutralized with triethanolamine, and the toluene was removed by vacuum for 30 min. The product was then discharged to obtain a crosslinking agent.

[0126] The structural formula of tetrahydroxymethylmelamine is as follows:

[0127]

[0128] The structural formula of the crosslinking agent is as follows:

[0129]

[0130] A negative chemical amplification photoresist composition comprises 11.02 g of poly(p-hydroxystyrene) resin, 0.756 g of trifluoromethanesulfonate thioonium salt, 0.756 g of the above-mentioned crosslinking agent, 5.04 g of a 1 wt% solution of triethanolamine in 1,2-propanediol methyl ether acetate, 1.07 g of a 1 wt% solution of surfactant BYK307 in 1,2-propanediol methyl ether acetate, and 51.35 g of 1,2-propanediol methyl ether acetate. After weighing and mixing the above substances, the mixture is stirred thoroughly until completely dissolved. The solution is then filtered through a 0.1 μm polytetrafluoroethylene microporous membrane to obtain the negative chemical amplification photoresist.

[0131] Example 2

[0132] This application provides a crosslinking agent and its preparation method, as well as a photoresist, which includes the following steps:

[0133] 2.0 mol hexadecylphenol, 1.0 mol dodecanol, and 100 mL xylene were added to a 500 mL round-bottom flask equipped with a stirrer, thermometer, and reflux condenser. The mixture was heated and stirred until the hexadecylphenol and dodecanol were completely dissolved in the xylene to obtain a first mixture. 0.8 g of nitric acid was added to the first mixture to obtain a second mixture. 1.0 mol of trimethylolmelamine was slowly added to the second mixture. The reaction temperature was controlled at 80 °C, and the mixture was reacted under reflux for 3.5 h to obtain an intermediate. The intermediate was neutralized with sodium hydroxide, and the xylene was removed by vacuum for 30 min. The product was then discharged to obtain a crosslinking agent.

[0134] The structural formula of trimethylol melamine is as follows:

[0135]

[0136] The structural formula of the crosslinking agent is as follows:

[0137]

[0138] A negative chemical amplification photoresist composition comprises 11.02 g of poly(p-hydroxystyrene) resin, 0.756 g of trifluoromethanesulfonate thioonium salt, 0.756 g of the above-mentioned crosslinking agent, 5.04 g of a 1 wt% solution of triethanolamine in 1,2-propanediol methyl ether acetate, 1.07 g of a 1 wt% solution of surfactant BYK307 in 1,2-propanediol methyl ether acetate, and 51.35 g of 1,2-propanediol methyl ether acetate. After weighing and mixing the above substances, the mixture is stirred thoroughly until completely dissolved. The solution is then filtered through a 0.1 μm polytetrafluoroethylene microporous membrane to obtain the negative chemical amplification photoresist.

[0139] Example 3

[0140] This application provides a crosslinking agent and its preparation method, as well as a photoresist, which includes the following steps:

[0141] 2.0 mol tetradecylphenol, 2.0 mol ethanol, and 100 mL xylene were added to a 500 mL round-bottom flask equipped with a stirrer, thermometer, and reflux condenser. The mixture was heated and stirred until the tetradecylphenol and ethanol were completely dissolved in the xylene to obtain a first mixture. 0.8 g nitric acid was added to the first mixture to obtain a second mixture. 1.0 mol tetramethylolmelamine was slowly added to the second mixture. The reaction temperature was controlled at 80 °C, and the mixture was reacted under reflux for 3.5 h to obtain an intermediate. The intermediate was neutralized with sodium hydroxide, and the xylene was removed by vacuum for 30 min. The product was then discharged to obtain a crosslinking agent.

[0142] The structural formula of tetrahydroxymethylmelamine is as follows:

[0143]

[0144] The structural formula of the crosslinking agent is as follows:

[0145]

[0146] A negative chemical amplification photoresist composition comprises 11.02 g of poly(p-hydroxystyrene) resin, 0.756 g of trifluoromethanesulfonate thioonium salt, 0.756 g of the above-mentioned crosslinking agent, 5.04 g of a 1 wt% solution of triethanolamine in 1,2-propanediol methyl ether acetate, 1.07 g of a 1 wt% solution of surfactant BYK307 in 1,2-propanediol methyl ether acetate, and 51.35 g of 1,2-propanediol methyl ether acetate. After weighing and mixing the above substances, the mixture is stirred thoroughly until completely dissolved. The solution is then filtered through a 0.1 μm polytetrafluoroethylene microporous membrane to obtain the negative chemical amplification photoresist.

[0147] Example 4

[0148] This application provides a crosslinking agent and its preparation method, as well as a photoresist, which includes the following steps:

[0149] 2.0 mol tetradecylphenol, 2.0 mol eicosyl alcohol, and 100 mL xylene were added to a 500 mL round-bottom flask equipped with a stirrer, thermometer, and reflux condenser. The mixture was heated and stirred until the tetradecylphenol and eicosyl alcohol were completely dissolved in the xylene to obtain a first mixture. 0.8 g nitric acid was added to the first mixture to obtain a second mixture. 1.0 mol tetramethylolmelamine was slowly added to the second mixture. The reaction temperature was controlled at 80 °C, and the mixture was reacted under reflux for 3.5 h to obtain an intermediate. The intermediate was neutralized with sodium hydroxide, and the xylene was removed by vacuum for 30 min. The product was then discharged to obtain a crosslinking agent.

[0150] The structural formula of tetrahydroxymethylmelamine is as follows:

[0151]

[0152] The structural formula of the crosslinking agent is as follows:

[0153]

[0154] A negative chemical amplification photoresist composition comprises 11.02 g of poly(p-hydroxystyrene) resin, 0.756 g of trifluoromethanesulfonate thioonium salt, 0.756 g of the above-mentioned crosslinking agent, 5.04 g of a 1 wt% solution of triethanolamine in 1,2-propanediol methyl ether acetate, 1.07 g of a 1 wt% solution of surfactant BYK307 in 1,2-propanediol methyl ether acetate, and 51.35 g of 1,2-propanediol methyl ether acetate. After weighing and mixing the above substances, the mixture is stirred thoroughly until completely dissolved. The solution is then filtered through a 0.1 μm polytetrafluoroethylene microporous membrane to obtain the negative chemical amplification photoresist.

[0155] Example 5

[0156] This application provides a crosslinking agent and its preparation method, as well as a photoresist, which includes the following steps:

[0157] 2.0 mol tetradecylphenol, 4.0 mol n-octanol, and 100 mL xylene were added to a 500 mL round-bottom flask equipped with a stirrer, thermometer, and reflux condenser. The mixture was heated and stirred until the tetradecylphenol and n-octanol were completely dissolved in the xylene to obtain a first mixture. 0.8 g nitric acid was added to the first mixture to obtain a second mixture. 1.0 mol hexamethylolmelamine was slowly added to the second mixture. The reaction temperature was controlled at 80 °C, and the mixture was reacted under reflux for 3.5 h to obtain an intermediate. The intermediate was neutralized with sodium hydroxide, and the xylene was removed by vacuum for 30 min. The product was then discharged to obtain a crosslinking agent.

[0158] The structural formula of hexamethylol melamine is as follows:

[0159]

[0160] The structural formula of the crosslinking agent is as follows:

[0161]

[0162] A negative chemical amplification photoresist composition comprises 11.02 g of poly(p-hydroxystyrene) resin, 0.756 g of trifluoromethanesulfonate thioonium salt, 0.756 g of the above-mentioned crosslinking agent, 5.04 g of a 1 wt% solution of triethanolamine in 1,2-propanediol methyl ether acetate, 1.07 g of a 1 wt% solution of surfactant BYK307 in 1,2-propanediol methyl ether acetate, and 51.35 g of 1,2-propanediol methyl ether acetate. After weighing and mixing the above substances, the mixture is stirred thoroughly until completely dissolved. The solution is then filtered through a 0.1 μm polytetrafluoroethylene microporous membrane to obtain the negative chemical amplification photoresist.

[0163] Comparative Example 1

[0164] This application provides a crosslinking agent and a photoresist in a comparative example, the structural formulas of which are as follows:

[0165]

[0166] A negative chemical amplification photoresist composition comprises 11.02 g of poly(p-hydroxystyrene) resin, 0.756 g of trifluoromethanesulfonate thioonium salt, 0.756 g of the above-mentioned crosslinking agent, 5.04 g of a 1 wt% solution of triethanolamine in 1,2-propanediol methyl ether acetate, 1.07 g of a 1 wt% solution of surfactant BYK307 in 1,2-propanediol methyl ether acetate, and 51.35 g of 1,2-propanediol methyl ether acetate. After weighing and mixing the above substances, the mixture is stirred thoroughly until completely dissolved. The solution is then filtered through a 0.1 μm polytetrafluoroethylene microporous membrane to obtain the negative chemical amplification photoresist.

[0167] Comparative Example 2

[0168] This application provides a crosslinking agent and its preparation method, as well as a photoresist, which includes the following steps:

[0169] 1.0 mol tetradecylphenol and 100 mL xylene were added to a 500 mL round-bottom flask equipped with a stirrer, thermometer, and reflux condenser. The mixture was heated and stirred until the tetradecylphenol was completely dissolved in the xylene to obtain a first mixture. 0.8 g nitric acid was added to the first mixture to obtain a second mixture. 1.0 mol trimethylolmelamine was slowly added to the second mixture. The reaction temperature was controlled at 80 °C, and the mixture was reacted under reflux for 3.5 h to obtain an intermediate. The intermediate was neutralized with sodium hydroxide, and the xylene was removed by vacuuming under reduced pressure for 30 min. The product was then discharged to obtain a crosslinking agent.

[0170] The structural formula of trimethylol melamine is as follows:

[0171]

[0172] The structural formula of the crosslinking agent is as follows:

[0173]

[0174] A negative chemical amplification photoresist composition comprises 11.02 g of poly(p-hydroxystyrene) resin, 0.756 g of trifluoromethanesulfonate thioonium salt, 0.756 g of the above-mentioned crosslinking agent, 5.04 g of a 1 wt% solution of triethanolamine in 1,2-propanediol methyl ether acetate, 1.07 g of a 1 wt% solution of surfactant BYK307 in 1,2-propanediol methyl ether acetate, and 51.35 g of 1,2-propanediol methyl ether acetate. After weighing and mixing the above substances, the mixture is stirred thoroughly until completely dissolved. The solution is then filtered through a 0.1 μm polytetrafluoroethylene microporous membrane to obtain the negative chemical amplification photoresist.

[0175] Experimental Example 1

[0176] The photoresists of Examples 1-5 and Comparative Examples 1-2 were spin-coated onto 8-inch single-crystal silicon wafers. After coating, the substrates coated with photoresist were pre-baked at 100°C for 60 seconds using a hot plate, adjusting the spin speed to achieve a film thickness of 0.6 μm after drying. The substrates were then exposed using a DUV exposure machine, followed by hot-plate baking at 115°C for 60 seconds. Finally, the substrates were developed by spraying with 2.38 wt% tetramethylammonium hydroxide for 60 seconds. After the operation, the developed patterns were compared using a CD-SEM (Hitachi S9220) and an X-SEM (S4800). Figures 3-8 As shown.

[0177] Depend on Figures 3-4 It is understood that the crosslinking agents in Examples 1-2 of this application can make the crosslinking reaction of the photoresist matrix resin more uniform, and significantly improve the morphological defects caused by excessively large local molecular weights (such as...). Figure 1 and Figure 2 As shown in the figure, the resulting graphic has more vertical lines and a window size of 0.6 μm.

[0178] Depend on Figures 5-6 It is known that the R10 group of the crosslinking agent in Examples 3-4 of this application is C2 alkyl and C20 alkyl, and the resulting pattern lines have relatively vertical edges and a window size of 0.4 μm.

[0179] Depend on Figure 7 It is known that the crosslinking agent of Example 5 of this application has 6 groups selected from at least one of the first group and the second group, and the edge portion of the resulting graphic line is not very perpendicular, with a window size of 0.3 μm.

[0180] Depend on Figure 8 As can be seen, the crosslinking agent in Comparative Example 1 of this application is an existing crosslinking agent, and the edges of the resulting graphic lines are mostly not perpendicular, with the window being only 0.2 μm.

[0181] The crosslinking agent in Comparative Example 2 of this application cannot cause the base resin of the photoresist to undergo a crosslinking reaction, and therefore cannot form a pattern.

[0182] Experimental Example 2

[0183] The photoresists of Examples 1 and 3 were reconstituted with the following formulation: 11.02 g of poly(p-hydroxystyrene) resin, 0.756 g of trifluoromethanesulfonate thioonium salt, 0.756 g of crosslinking agent, 5.04 g of a 1 wt% solution of triethanolamine in 1,2-propanediol methyl ether acetate, 1.07 g of a 1 wt% solution of surfactant BYK307 in 1,2-propanediol methyl ether acetate, and 12.85 g of 1,2-propanediol methyl ether acetate. After weighing and mixing the above substances, the mixture was stirred thoroughly until completely dissolved. The solution was then filtered through a 0.1 μm polytetrafluoroethylene microporous membrane to obtain the negative chemical amplification photoresist.

[0184] The photoresists from Examples 1 and 3 were spin-coated onto an 8-inch single-crystal silicon wafer. After coating, the substrate coated with photoresist was pre-baked at 120°C for 180 seconds using a hot plate, adjusting the spin speed to achieve a dried film thickness of 20.0 μm. The substrate was then exposed using a DUV exposure machine, followed by hot-plate baking at 110°C for 60 seconds. Finally, the substrate was developed by spraying with 2.38 wt% tetramethylammonium hydroxide for 60 seconds. After the operation, the developed patterns were compared using a CD-SEM (Hitachi S9220) and an X-SEM (S4800). Figure 9 and 10 As shown.

[0185] A comparison of Examples 1 and 3 shows that there is no cracking between the photoresist layer and the substrate in Example 1, while there is cracking between the photoresist layer and the substrate in Example 3. This indicates that the crosslinking agent in Example 1 of this application, by adjusting the structure of the active groups and the number of active sites, can alleviate the stress problem between the substrate and the photoresist caused by the hard film, thereby reducing the risk of photoresist layer deformation and cracking.

[0186] The above description is merely a specific embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a crosslinking agent, characterized in that, The preparation method of the crosslinking agent includes: reacting hydroxyalkyl melamine and reactants with an acid catalytic reaction to obtain an intermediate, and then neutralizing the intermediate; The structural formula of the hydroxyalkyl melamine is as follows: Wherein, the R 11 The R 12 The R 13 The R 14 The R 15 and the R 16 Each is independently selected from H or -R 17 -OH; The R 17 Selected from C 1~10 alkyl; The R 11 The R 12 The R 13 The R 14 The R 15 and the R 16 Any two of them are selected from -R 17 -OH; The reactants are selected from at least one of alkylphenol compounds and alcohols, wherein the alkylphenol compounds are selected from any one or more of cresol, xylenol, ethylphenol, propylphenol, tert-butylphenol, pentylphenol, hepta-phenol, octylphenol, 2,4-di-tert-butylphenol, nonylphenol, decylphenol, dodecylphenol, tetradecylphenol, hexadecylphenol, octadecylphenol, and cashew phenol; The alcohols are selected from any one or more of methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, deca-ol, dodecanol, tetradecylol, hexadecylol, octadecanol, and eicosylol; The crosslinking agent has the following structural formula: Wherein, R3 and R6 are both first groups, and R1 and R2 are both second groups, or one of them is a second group and the other is H, and R4 and R5 are both H or both are second groups; The structural formula of the first group is ; The structural formula of the second group is -R9-OR 10 ; R7 is selected from C. 1~10 alkyl; R8 is selected from H or C. 1~20 alkyl; R9 is selected from C. 1~10 alkyl; The R 10 Selected from C 1~20 alkyl.

2. The method for preparing the crosslinking agent according to claim 1, characterized in that, The acidic catalytic reaction temperature is 50℃~150℃, and the reaction time is 0.4h~12h.

3. The method for preparing the crosslinking agent according to claim 1, characterized in that, The molar ratio of the hydroxyalkyl melamine to the reactants is 1:2 to 1:

5.

4. A photoresist, characterized in that, The photoresist comprises a solute and a first solvent, wherein the solute comprises 70wt%~95wt% alkali-soluble resin, 1wt%~30wt% photoacid-generating agent, 0.1wt%~15wt% acid quencher, and 5wt%~20wt% crosslinking agent prepared by the method of crosslinking agent according to any one of claims 1 to 3, and the mass of the first solvent is 1 to 10 times the mass of the alkali-soluble resin.

5. The photoresist according to claim 4, characterized in that, The alkali-soluble resin is any one or more of poly(p-hydroxystyrene) resin, polystyrene resin, poly(p-hydroxystyrene) resin, and linear phenolic resin.

6. The photoresist according to claim 4, characterized in that, The photo-induced acid-producing agent is any one or more of iodonium salts, thiodonium salts, and heterocyclic acid-producing agents.

7. The photoresist according to claim 4, characterized in that, The acid quencher is an alkaline organic compound.

8. The photoresist according to claim 7, characterized in that, The alkaline organic compounds are tertiary ammonium compounds and / or quaternary ammonium compounds.

9. The photoresist according to claim 4, characterized in that, The first solvent is any one or more of 1,2-propanediol methyl ether acetate, ethyl lactate, and ethyl acetate.

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