A highly stable anti-reflective coating and its preparation method

Abstract

This invention belongs to the field of photolithography technology, specifically relating to a highly stable anti-reflective coating and its preparation method. The anti-reflective coating comprises the following components in parts by weight: 3-5 parts of matting resin, 6-9 parts of crosslinking agent, and 100-120 parts of solvent. After spin-coating, this anti-reflective coating exhibits excellent film thickness uniformity and resistance to neutral salt spray. Its refractive index and extinction coefficient meet the optical parameter requirements of the bottom anti-reflective coating. Furthermore, after storage at different temperatures for 12 months, the refractive index and extinction coefficient show no significant change, demonstrating extremely high storage stability.

Description

Technical Field

[0001] This invention belongs to the field of photolithography technology, specifically relating to a highly stable anti-reflective coating and its preparation method. Background Technology

[0002] In the photolithography process of semiconductor chip manufacturing, the exposure accuracy of the photoresist directly determines the accuracy of the circuit pattern. The reflection of ultraviolet light by the substrate material causes abnormal exposure of the photoresist, leading to pattern deformation, standing wave effect, and reflective notching. Anti-reflective coatings (BARC) solve this problem by suppressing reflection interference, improving the process window, and improving substrate flatness; their refractive index must be between that of the photoresist and the substrate.

[0003] However, existing organic BARC technology has key drawbacks: spin coating requires precise thickness control, but the uncontrollable crosslinking reaction rate (too fast for epoxy compounds leads to internal stress cracks, too slow for hydroxyl compounds leads to solvent residue) results in uneven film thickness; insufficient refractive index reproducibility and thermal stability, with the high thermal expansion coefficient of the aliphatic framework causing optical parameter drift; poor photochemical stability, with oxidation and yellowing of unsaturated structures causing a decrease in the extinction coefficient; short shelf life, with pre-reaction of highly reactive groups leading to gelation, and deterioration of filterability and process repeatability. These drawbacks make it difficult for BARC to simultaneously meet the multiple requirements of uniform film thickness, long-term stable optical performance, and controllable storage, thus limiting the improvement of photolithography precision.

[0004] There is an urgent need for an anti-reflective coating that combines uniform film thickness, long-term stable refractive index, and controllable and stable extinction coefficient to solve the problem of pattern deformation caused by substrate reflection. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, one of the objectives of this invention is to provide a highly stable anti-reflective coating. This coating, after spin-coating, exhibits excellent film thickness uniformity and resistance to neutral salt spray. Its refractive index and extinction coefficient meet the optical parameter requirements of the bottom anti-reflective coating. Furthermore, after storage at different temperatures for 12 months, the refractive index and extinction coefficient show no significant changes, demonstrating extremely high storage stability.

[0006] The second objective of this invention is to provide a method for preparing a highly stable anti-reflective coating that is simple to operate.

[0007] The objective of this invention is achieved through the following technical solution: A highly stable anti-reflective coating comprises the following components in parts by weight: 3-5 parts of matting resin, 6-9 parts of crosslinking agent, and 100-120 parts of solvent; The crosslinking agent has the following structural formula: .

[0008] Preferably, the preparation process of the matting resin includes the following steps: (1) Ethyl acrylate and isophorone diamine were added to anhydrous ethanol, and after reaction and purification, N-((5-amino-1,3,3-trimethylcyclohexyl)methyl)acrylamide was obtained; The structural formula of the N-((5-amino-1,3,3-trimethylcyclohexyl)methyl)acrylamide is: (2) Under an inert gas atmosphere, methyl 9-anthracene methacrylate, hydroxypropyl methacrylate, and the N-((5-amino-1,3,3-trimethylcyclohexyl)methyl)acrylamide were added to anhydrous 1,4-dioxane, and then an initiator was added. After the reaction, the mixture was purified to obtain the matting resin.

[0009] This invention prepares N-((5-amino-1,3,3-trimethylcyclohexyl)methyl)acrylamide by amide condensation reaction of acrylate with the amino group of isophorone diamine; then, it undergoes free radical addition reaction with methyl methacrylate-9-anthracene and hydroxypropyl methacrylate under the action of an initiator to obtain a matting resin.

[0010] Preferably, the molar ratio of ethyl acrylate and isophorone diamine in step (1) is 1:(1.2-1.5); the reaction temperature is 50-60℃ and the reaction time is 2-5h.

[0011] Preferably, in step (2), the molar ratio of methyl 9-anthracene methacrylate, hydroxypropyl methacrylate, N-((5-amino-1,3,3-trimethylcyclohexyl)methyl)acrylamide, and the initiator is 1:(1-1.2):(1.1-1.4):(0.26-0.5); the initiator is 2,2'-azobisisobutyronitrile; the reaction temperature is 80-85℃, and the reaction time is 10-12h.

[0012] Preferably, the preparation process of the crosslinking agent includes the following steps: S1. Honokiol, 3,7,11-trimethyldodecane-3-ol, triphenylphosphine, and di-tert-butyl azodicarbonate were added to tetrahydrofuran and heated to react. After cooling, diethylene glycol and diethyl azodicarbonate were added. After reaction, the mixture was purified to obtain intermediate 1. The structural formula of intermediate 1 is as follows: S2. Under inert gas protection, m-chloroperoxybenzoic acid was added to dichloromethane, and intermediate 1 was added at 5-10°C. After reaction, the mixture was purified to obtain intermediate 2. The structural formula of intermediate 2 is as follows: S3. The intermediate 2 is subjected to a cycloaddition reaction with CO2 under the action of bis(triphenylphosphine)ammonium chloride, and after purification, the crosslinking agent is obtained.

[0013] This invention involves a stepwise reaction in which the phenolic hydroxyl groups of magnolol are linked to the hydroxyl groups of 3,7,11-trimethyldodecane-3-ol and diethylene glycol via ether bonds to obtain intermediate 1. The carbon-carbon double bond in intermediate 1 is then oxidized to ethylene oxide with m-chloroperoxybenzoic acid to obtain intermediate 2. The ethylene oxide in intermediate 2 is converted into cyclic carbonate through a carbonyl insertion reaction to obtain a crosslinking agent.

[0014] Preferably, in step S1, the molar ratio of magnolol, 3,7,11-trimethyldodecane-3-ol, triphenylphosphine, di-tert-butyl azodicarbonate, diethylene glycol, and diethyl azodicarbonate is 1:(1-1.2):(1.1-1.3):(1.1-1.3):(1.1-1.3):(1.1-1.3); the heating temperature is 70-75℃, and the time is 12-18h; the cooling temperature is reduced to 20-25℃, and the reaction time is 6-10h.

[0015] Preferably, in step S2, the molar ratio of intermediate 1 to m-chloroperoxybenzoic acid is 1:(3-4); the reaction temperature is 20-25℃ and the reaction time is 8-12h.

[0016] Preferably, the molar ratio of intermediate 2 and bis(triphenylphosphine)ammonium chloride in step S3 is 1:(0.005-0.015); the cycloaddition reaction is carried out in an autoclave at 110-130°C for 48-72 hours with 40 bar carbon dioxide as the reaction gas.

[0017] Preferably, the solvent is propylene glycol methyl ether acetate or methyl 2-hydroxyisobutyrate.

[0018] The preparation method of the above-mentioned highly stable anti-reflective coating includes the following steps: Simply mix the matting resin, crosslinking agent, and solvent thoroughly.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a highly stable anti-reflective coating, comprising the following components: matting resin, crosslinking agent, and solvent. After spin coating, this coating exhibits excellent film thickness uniformity and resistance to neutral salt spray. Its refractive index and extinction coefficient meet the optical parameter requirements of the bottom anti-reflective coating. Furthermore, after storage at different temperatures for 12 months, the refractive index and extinction coefficient show no significant change, demonstrating extremely high storage stability.

[0020] 2. The matting resin in the antireflective coating of this invention is a key component that imparts excellent resistance to neutral salt spray, uniform film thickness, and storage stability to the coating. Its mechanism of action is as follows: During spin coating, the primary amine group of N-((5-amino-1,3,3-trimethylcyclohexyl)methyl)acrylamide in the matting resin undergoes a nucleophilic ring-opening reaction with the cyclic carbonate in the crosslinking agent at the baking temperature. This reaction is more reactive than the hydroxyl group, dominating the rapid shaping of the network backbone and allowing the solvent to cure before full evaporation, thus achieving excellent film thickness uniformity. The byproduct hydroxyl groups further participate in secondary crosslinking, increasing the crosslinking density and forming a dense and complete network structure, imparting excellent resistance to neutral salt spray to the coating. Simultaneously, the rigid structure of the 3,3-trimethylcyclohexyl group restricts the thermal motion of chain segments, reducing thermally induced free volume expansion and maintaining constant coating density and polarizability, resulting in stable refractive index after storage.

[0021] 3. The crosslinking agent in the antireflective coating of this invention is also a key component for achieving excellent resistance to neutral salt spray, uniform film thickness, and storage stability. Its mechanism of action is as follows: The bicyclic carbonate end groups of the crosslinking agent are exposed on the outer layer of the molecule in solution, forming a reaction precursor structure with the N-((5-amino-1,3,3-trimethylcyclohexyl)methyl)acrylamide primary amine group in the matting resin. During baking, the rings are opened by nucleophilic attack, constructing a three-dimensional network framework. The remaining cyclic carbonates undergo secondary reactions with hydroxyl groups to achieve graded curing, effectively reducing volume shrinkage. The 3,7,11-trimethyldodecane-3-ol in the crosslinking agent reduces surface tension and improves leveling, while the diethylene glycol polyether segments regulate compatibility with the matting resin. The low shrinkage characteristics of the chemical structure and the homogenizing effect of the physical rheology work synergistically to further improve film thickness uniformity. Simultaneously, the high crosslinking density network reduces the free volume and micropore defects inside the coating, effectively blocking the penetration of corrosive media such as chloride ions in salt spray. In addition, the biphenyl skeleton of honokiol provides inherent UV absorption, which, together with the anthracene ring in the matting resin, synergistically regulates the extinction coefficient to the target range. Detailed Implementation

[0022] The present invention will be further described in conjunction with specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments. Specific conditions not specified in the embodiments are based on conventional conditions or product instructions. Unless otherwise specified, all reagents or instruments used are conventional products obtained through commercial channels.

[0023] Preparation Example 1 A matting resin, prepared as follows: (1) Ethyl acrylate (10 mmol) and isophorone diamine (13 mmol) were added to 20 mL of anhydrous ethanol and reacted at 55 °C for 4 h. The mixture was concentrated under reduced pressure, and the residue was dispersed in ether and stirred for 30 min. The mixture was then filtered, the filter cake was washed with ether and dried to obtain N-((5-amino-1,3,3-trimethylcyclohexyl)methyl)acrylamide. The structural formula of N-((5-amino-1,3,3-trimethylcyclohexyl)methyl)acrylamide is: The NMR and mass spectrometry results for N-((5-amino-1,3,3-trimethylcyclohexyl)methyl)acrylamide are as follows: 1 HNMR (C 13 H 24 N2O, 400MHz, DMSO- d6 )δ8.41(s,1H),6.48(dd,1H),6.09(dd,1H),5.74(dd,1H),2.96-2.58(m,3H),1.67-1.07(m,8H),0.93(s,3H),0.87(s,6H);LC-MSm / z:225.19[M+H] + .

[0024] (2) Under a nitrogen atmosphere, methyl 9-anthracene methacrylate (CAS: 31645-35-9, 30 mmol), hydroxypropyl methacrylate (33 mmol), and N-((5-amino-1,3,3-trimethylcyclohexyl)methyl)acrylamide (40 mmol) were dissolved in 100 mL of anhydrous 1,4-dioxane, and then 2,2'-azobisisobutyronitrile (10 mmol) was added. The reaction was carried out at 82 °C for 11 h. After cooling, the reaction solution was added dropwise to 500 mL of methanol to precipitate the product. The product was then dried in a vacuum drying oven at 50 °C for 10 h to obtain matting resin (Mw=17690).

[0025] Preparation Example 2 A matting resin, prepared as follows: (1) Ethyl acrylate (10 mmol) and isophorone diamine (12 mmol) were added to 20 mL of anhydrous ethanol and reacted at 50 °C for 5 h. The mixture was concentrated under reduced pressure, and the residue was dispersed in ether and stirred for 30 min. The residue was then filtered, washed with ether, and dried to obtain N-((5-amino-1,3,3-trimethylcyclohexyl)methyl)acrylamide. The structural formula, NMR and mass spectrometry results of N-((5-amino-1,3,3-trimethylcyclohexyl)methyl)acrylamide were consistent with those of Preparation Example 1.

[0026] (2) Under a nitrogen atmosphere, methyl 9-anthracene methacrylate (30 mmol), hydroxypropyl methacrylate (30 mmol), and N-((5-amino-1,3,3-trimethylcyclohexyl)methyl)acrylamide (33 mmol) were dissolved in 100 mL of anhydrous 1,4-dioxane, and then 2,2'-azobisisobutyronitrile (7.8 mmol) was added. The mixture was reacted at 80 °C for 12 h. After cooling, the reaction solution was added dropwise to 500 mL of methanol to precipitate the resin. The resin was dried in a vacuum drying oven at 50 °C for 10 h to obtain matting resin (Mw=15263).

[0027] Preparation Example 3 A matting resin, prepared as follows: (1) Ethyl acrylate (10 mmol) and isophorone diamine (15 mmol) were added to 20 mL of anhydrous ethanol and reacted at 60 °C for 2 h. The mixture was concentrated under reduced pressure, and the residue was dispersed in ether and stirred for 30 min. The mixture was then filtered, the filter cake was washed with ether, and dried to obtain N-((5-amino-1,3,3-trimethylcyclohexyl)methyl)acrylamide. The structural formula, NMR and mass spectrometry results of N-((5-amino-1,3,3-trimethylcyclohexyl)methyl)acrylamide were consistent with those of Preparation Example 1.

[0028] (2) Under a nitrogen atmosphere, methyl 9-anthracene methacrylate (30 mmol), hydroxypropyl methacrylate (36 mmol), and N-((5-amino-1,3,3-trimethylcyclohexyl)methyl)acrylamide (42 mmol) were dissolved in 100 mL of anhydrous 1,4-dioxane, and then 2,2'-azobisisobutyronitrile (15 mmol) was added. The mixture was reacted at 85 °C for 10 h. After cooling, the reaction solution was added dropwise to 500 mL of methanol to precipitate the resin. The resin was dried in a vacuum drying oven at 50 °C for 10 h to obtain matting resin (Mw=18175).

[0029] Preparation Example 4 Based on Preparation Example 1, step (1) was omitted, and N-((5-amino-1,3,3-trimethylcyclohexyl)methyl)acrylamide in step (2) was replaced with ethyl acrylate to form Preparation Example 4.

[0030] Preparation Example 5 A crosslinking agent, prepared by the following method: S1. Honokiol (CAS: 35354-74-6, 10 mmol), 3,7,11-trimethyldodecane-3-ol (CAS: 7278-65-1, 11 mmol), triphenylphosphine (12 mmol), and di-tert-butyl azodicarbonate (12 mmol) were added to 30 mL of tetrahydrofuran, stirred until homogeneous, and heated to 72 °C for 16 h. After cooling to 22 °C, diethylene glycol (12 mmol) and diethyl azodicarbonate (12 mmol) were added, and the reaction was carried out for 8 h. After the reaction was completed, the reaction solution was concentrated under reduced pressure, and the residue was subjected to column chromatography (V... 石油醚 :V 乙酸乙酯 The mixture was purified by a ratio of 7:1 to obtain intermediate 1; the NMR and mass spectrometry results of intermediate 1 are as follows: 1 HNMR (C 37 H 56 O4, 400MHz, DMSO- d6 )δ8.09(d,2H),7.72(d,1H),7.23(d,1H),7.15(d,2H),5.96-5.94(m,2H),5.40(s,1H),5.12-4.80(m,4H),4.32(t,2H),3.77-3. 70(m,4H),3.54(t,2H),3.35(d,4H),1.82(q,2H),1.62-1.57(m,3H),1.42-1.20(m,14H),0.91(q,12H);LC-MSm / z:565.42[M+H] + .

[0031] S2. Under a nitrogen atmosphere, m-chloroperoxybenzoic acid (35 mmol) was added to 30 mL of dichloromethane and stirred until homogeneous. Intermediate 1 (10 mmol) was added at 8 °C, and the mixture was stirred for 30 min after the addition was complete. The reaction was then carried out at 22 °C for 10 h. The reaction was quenched with saturated sodium sulfite solution, and the pH of the reaction solution was neutralized to neutral with saturated sodium bicarbonate solution. The aqueous phase was extracted with dichloromethane, and the organic phases were combined, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue was subjected to silica gel chromatography (V... 石油醚 V 乙酸乙酯 The mixture was purified at a ratio of 5:1 to obtain intermediate 2. The NMR and mass spectrometry results of intermediate 2 are as follows: 1 HNMR (C 37 H 56 O6, 400MHz, DMSO- d6)δ7.82(d,2H),7.62(dd,1H),7.23(dd,1H),7.15(d,2H),5.40(s,1H),4.32(t,2H),3.77-3.70(m,4H),3.54(t,2 H),2.92-2.35(m,10H),1.82(q,2H),1.62-1.57(m,3H),1.42-1.20(m,14H),0.91(q,12H);LC-MSm / z:596.42[M].

[0032] S3. Intermediate 2 (20 mmol) and bis(triphenylphosphine)ammonium chloride (CAS: 21050-13-5, 0.2 mmol) were added to an autoclave reactor, CO2 was introduced to 40 bar, and the reaction was carried out at 120 °C for 60 h. After the reaction was completed, the mixture was cooled to room temperature and analyzed by silica gel chromatography (V). 正庚烷 V 乙酸乙酯 The crosslinking agent was obtained by purification at a ratio of 4:1; the NMR and mass spectrometry results of the crosslinking agent are as follows: 1 HNMR (C 39 H 56 O 10 400MHz, DMSO- d6 )δ7.82(d,2H),7.62(dd,1H),7.23(dd,1H),7.15(d,2H),5.40(s,1H),4.60-4.58(m,2H),4.32-4.26(m,4H),4.01(q,2H),3.77-3.70(m ,4H),3.54(t,2H),2.91(q,2H),2.65(q,2H),1.82(q,2H),1.62-1.57(m,3H),1.42-1.20(m,14H),0.91(q,12H);LC-MSm / z:685.39[M+H] + .

[0033] Preparation Example 6 A crosslinking agent, prepared by the following method: S1. Honokiol (10 mmol), 3,7,11-trimethyldodecane-3-ol (10 mmol), triphenylphosphine (11 mmol), and di-tert-butyl azodicarbonate (11 mmol) were added to 30 mL of tetrahydrofuran, stirred until homogeneous, and heated to 70 °C for 18 h. After cooling to 20 °C, diethylene glycol (11 mmol) and diethyl azodicarbonate (11 mmol) were added, and the reaction was carried out for 6 h. After the reaction was completed, the reaction solution was concentrated under reduced pressure, and the residue was subjected to column chromatography (V... 石油醚 :V 乙酸乙酯The mixture was purified by a ratio of 7:1 to obtain intermediate 1; the NMR and mass spectrometry results of intermediate 1 were consistent with those of preparation example 4.

[0034] S2. Under a nitrogen atmosphere, 30 mmol of m-chloroperoxybenzoic acid was added to 30 mL of dichloromethane and stirred until homogeneous. Intermediate 1 (10 mmol) was added at 5 °C, and the mixture was stirred for 30 min after addition. The reaction was then carried out at 20 °C for 12 h. The reaction was quenched with saturated sodium sulfite solution, and the pH of the reaction solution was neutralized to neutral with saturated sodium bicarbonate solution. The aqueous phase was extracted with dichloromethane, and the organic phases were combined, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue was then subjected to silica gel chromatography (V...). 石油醚 V 乙酸乙酯 The mixture was purified by a ratio of 5:1 to obtain intermediate 2; the NMR and mass spectrometry results of intermediate 2 were consistent with those of preparation example 4.

[0035] S3. Intermediate 2 (20 mmol) and bis(triphenylphosphino)ammonium chloride (0.1 mmol) were added to an autoclave reactor, CO2 was introduced to 40 bar, and the reaction was carried out at 110 °C for 72 h. After the reaction was completed, the mixture was cooled to room temperature and analyzed by silica gel chromatography (V). 正庚烷 V 乙酸乙酯 The crosslinking agent was prepared by purification at a ratio of 4:1; the NMR and mass spectrometry results of the crosslinking agent were consistent with those of Preparation Example 4.

[0036] Preparation Example 7 A crosslinking agent, prepared by the following method: S1. Honokiol (10 mmol), 3,7,11-trimethyldodecane-3-ol (12 mmol), triphenylphosphine (13 mmol), and di-tert-butyl azodicarbonate (13 mmol) were added to 30 mL of tetrahydrofuran, stirred until homogeneous, and heated to 75 °C for 12 h. After cooling to 25 °C, diethylene glycol (13 mmol) and diethyl azodicarbonate (13 mmol) were added, and the reaction was carried out for 10 h. After the reaction was completed, the reaction solution was concentrated under reduced pressure, and the residue was subjected to column chromatography (V... 石油醚 :V 乙酸乙酯 The mixture was purified by a ratio of 7:1 to obtain intermediate 1; the NMR and mass spectrometry results of intermediate 1 were consistent with those of preparation example 4.

[0037] S2. Under a nitrogen atmosphere, 40 mmol of m-chloroperoxybenzoic acid was added to 30 mL of dichloromethane and stirred until homogeneous. Intermediate 1 (10 mmol) was added at 10 °C, and the mixture was stirred for 30 min after the addition was complete. The reaction was then carried out at 25 °C for 8 h. The reaction was quenched with saturated sodium sulfite solution, and the pH of the reaction solution was neutralized to neutral with saturated sodium bicarbonate solution. The aqueous phase was extracted with dichloromethane, and the organic phases were combined, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue was then subjected to silica gel chromatography (V...). 石油醚 V 乙酸乙酯The mixture was purified by a ratio of 5:1 to obtain intermediate 2; the NMR and mass spectrometry results of intermediate 2 were consistent with those of preparation example 4.

[0038] S3. Intermediate 2 (20 mmol) and bis(triphenylphosphine)ammonium chloride (0.3 mmol) were added to an autoclave reactor, CO2 was introduced to 40 bar, and the reaction was carried out at 130 °C for 48 h. After the reaction was completed, the mixture was cooled to room temperature and analyzed by silica gel chromatography (V). 正庚烷 V 乙酸乙酯 The crosslinking agent was prepared by purification at a ratio of 4:1; the NMR and mass spectrometry results of the crosslinking agent were consistent with those of Preparation Example 4.

[0039] Example 1 A highly stable antireflective coating comprises the following components in parts by weight: 4 parts of the matting resin of Preparation Example 1, 7.5 parts of the crosslinking agent of Preparation Example 5, and 110 parts of propylene glycol methyl ether acetate.

[0040] The preparation method of the above-mentioned highly stable anti-reflective coating includes the following steps: The matting resin, crosslinking agent, and propylene glycol methyl ether acetate are mixed evenly and filtered through a 0.45 μm filter membrane to obtain a highly stable anti-reflective coating.

[0041] Example 2 A highly stable antireflective coating comprises the following components in parts by weight: 3 parts of the matting resin of Preparation Example 2, 6 parts of the crosslinking agent of Preparation Example 6, and 100 parts of methyl 2-hydroxyisobutyrate.

[0042] The preparation method of the above-mentioned highly stable anti-reflective coating includes the following steps: The matting resin, crosslinking agent, and methyl 2-hydroxyisobutyrate are mixed evenly and filtered through a 0.45μm filter membrane to obtain a highly stable antireflective coating.

[0043] Example 3 A highly stable antireflective coating comprises the following components in parts by weight: 5 parts of the matting resin of Preparation Example 3, 9 parts of the crosslinking agent of Preparation Example 7, and 120 parts of propylene glycol methyl ether acetate.

[0044] The preparation method of the above-mentioned highly stable anti-reflective coating includes the following steps: The matting resin, crosslinking agent, and propylene glycol methyl ether acetate are mixed evenly and filtered through a 0.45 μm filter membrane to obtain a highly stable anti-reflective coating.

[0045] Comparative Example 1 Based on Example 1, the intermediate 2 obtained in step S2 of Preparation Example 5 was used to replace the crosslinking agent in Preparation Example 5 to form Comparative Example 1.

[0046] Comparative Example 2 Based on Example 1, 3',5-bis[(ethylene oxide-2-yl)methyl]-[1,1'-biphenyl]-2,4'-diol was used to replace the crosslinking agent in Preparation Example 5 to form Comparative Example 2.

[0047] Comparative Example 3 Based on Example 1, the matting resin of Preparation Example 4 was used instead of the matting resin of Preparation Example 1 to form Comparative Example 3.

[0048] Experimental Example 1 The antireflective coating prepared in the examples or comparative examples was spin-coated onto the surface of a silicon wafer, and then baked at 200°C for 120 seconds. After crosslinking, 100 points were taken to measure the film thickness uniformity of the coating surface. Film thickness uniformity = (maximum film thickness - minimum film thickness) / (maximum film thickness + minimum film thickness) × 100%. The test results are shown in Table 1.

[0049] Referring to GB / T 10125-2021 "Artificial Atmosphere Corrosion Test - Salt Spray Test", the resistance of each sample to neutral salt spray was tested, and the time when the coating blistered or cracked was recorded. The test results are shown in Table 1.

[0050] Table 1 Table 1 shows that after spin-coating, the high-stability antireflective coatings of Examples 1-3 exhibited a film thickness uniformity of less than 0.09% and a neutral salt spray resistance time of over 281 hours. This indicates that the present invention utilizes the nucleophilic ring-opening reaction between a bicyclic carbonate crosslinking agent and a matting resin containing primary / secondary amines to achieve effective control of the crosslinking rate and graded curing. Simultaneously, the leveling effect of the flexible long chains in the crosslinking agent significantly improves the film thickness uniformity of the BARC coating. Furthermore, the dense and uniform crosslinked network structure endows the coating with excellent resistance to corrosive media penetration.

[0051] Comparative Example 1 used intermediate 2, which contained only ethylene oxide, instead of the crosslinking agent of the present invention. The crosslinking reaction was too fast and uncontrollable, resulting in high internal stress and numerous defects in the film layer, leading to a decrease in both film thickness uniformity and salt spray resistance. Comparative Example 2 used a structurally mismatched biphenyl diepoxy crosslinking agent, lacking flexible segments and the graded curing characteristics of cyclic carbonates. It had the worst film thickness uniformity, and the crosslinking network was rigid and low in density, resulting in the lowest salt spray resistance of only 139 hours among all groups. The matte resin in Comparative Example 3 did not contain amine groups, making it unable to react efficiently with cyclic carbonates. The crosslinking was uneven and slow, resulting in a film thickness uniformity of 0.62% and a salt spray resistance of 152 hours.

[0052] The above comparison fully verifies the synergistic mechanism of the crosslinking agent with a specific structure and the amine-containing matting resin in this invention: the bicyclic carbonate provides graded curing, the flexible long chain improves leveling, and the rigid cyclohexyl group enhances network stability. Together, these three factors achieve a balance between high film thickness uniformity and excellent salt spray resistance.

[0053] Experimental Example 2 Before the experiment, the antireflective coatings of the examples or comparative examples were spin-coated onto the wafer at a speed of 1500 rpm, and then baked at 150°C for 60 s to form a bottom antireflective coating (BARC coating) with a thickness of 800 Å. The refractive index n and extinction coefficient k of each BARC coating were then measured at a wavelength of 193 nm using a spectroelliptic spectrometer. The results are shown in Table 2.

[0054] The antireflective coatings obtained from the above embodiments or comparative examples were stored in environments of 5°C, 20°C, and 45°C, respectively. After storage for 1 month, 2 months, 5 months, 8 months, and 12 months, the refractive index n and extinction coefficient k of each sample were tested according to the above measurement method. The results are shown in Table 3.

[0055] Table 2 Table 3 As shown in Table 2, the BARC coatings in Examples 1-3 have a refractive index n of 1.75-1.80 and an extinction coefficient k of 0.31-0.35 at a wavelength of 193 nm, which are within a reasonable range for bottom anti-reflective coatings. The n and k values ​​in Comparative Example 1 are significantly higher, while those in Comparative Examples 2 and 3 are significantly lower, all deviating from the ideal optical window. This is directly related to the structural defects of their cross-linked networks.

[0056] As shown in Table 3, the antireflective coatings of Examples 1-3 did not change in refractive index n and extinction coefficient k after being stored at 5℃, 20℃ and 45℃ for 12 months. This indicates that the crosslinking network formed by the bicyclic carbonate crosslinking agent and the primary / secondary amine extinction resin of the present invention has extremely high structural stability and can effectively suppress factors such as post-crosslinking, degradation or moisture absorption during storage that cause optical parameter drift.

[0057] Comparative Example 1 was basically stable at 5℃, but n and k gradually decreased with prolonged storage time at 20℃ and 45℃, indicating that the crosslinking system containing only ethylene oxide exhibits continuous crosslinking or chain rearrangement at high temperatures, resulting in insufficient stability. Comparative Example 2 showed slight degradation at 5℃, with more significant degradation at 20℃ and 45℃. This is attributed to its lack of flexible segments and hierarchical curing characteristics, resulting in a rigid crosslinking network with high stress, making it prone to microcracks or chain breakage during storage. Comparative Example 3 showed significant degradation at all temperatures, confirming that the primary / secondary amine groups are key to the efficient reaction with cyclic carbonates and the construction of a stable crosslinking network.

[0058] In summary, this invention, through the synergistic effect of a crosslinking agent with a specific structure and a matting resin containing primary / secondary amines, not only enables the BARC coating to obtain ideal optical constants, but also endows it with excellent storage stability for up to 12 months over a wide temperature range. This provides key technical support for the long-term reliable application of anti-reflective coatings in photolithography processes.

[0059] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A high-stability antireflection coating, characterized by, It includes the following components in parts by weight: 3-5 parts matting resin, 6-9 parts crosslinking agent, and 100-120 parts solvent; The crosslinking agent has the following structural formula: ； The preparation process of the matting resin includes the following steps: (1) Ethyl acrylate and isophorone diamine were added to anhydrous ethanol, and after reaction and purification, N-((5-amino-1,3,3-trimethylcyclohexyl)methyl)acrylamide was obtained; The structural formula of the N-((5-amino-1,3,3-trimethylcyclohexyl)methyl)acrylamide is: (2) Under an inert gas atmosphere, methyl 9-anthracene methacrylate, hydroxypropyl methacrylate, and the N-((5-amino-1,3,3-trimethylcyclohexyl)methyl)acrylamide were added to anhydrous 1,4-dioxane, and then an initiator was added. After the reaction, the mixture was purified to obtain the matting resin.

2. The high-stability anti-reflective coating according to claim 1, characterized in that, The molar ratio of ethyl acrylate and isophorone diamine in step (1) is 1:(1.2-1.5); the reaction temperature is 50-60℃ and the reaction time is 2-5h.

3. The high-stability anti-reflective coating according to claim 1, wherein In step (2), the molar ratio of methyl 9-anthracene methacrylate, hydroxypropyl methacrylate, N-((5-amino-1,3,3-trimethylcyclohexyl)methyl)acrylamide, and the initiator is 1:(1-1.2):(1.1-1.4):(0.26-0.5); the initiator is 2,2'-azobisisobutyronitrile; the reaction temperature is 80-85℃, and the reaction time is 10-12h.

4. The high-stability anti-reflective coating of claim 1, wherein, The preparation process of the crosslinking agent includes the following steps: S1. Honokiol, 3,7,11-trimethyldodecane-3-ol, triphenylphosphine, and di-tert-butyl azodicarbonate were added to tetrahydrofuran and heated to react. After cooling, diethylene glycol and diethyl azodicarbonate were added. After reaction, the mixture was purified to obtain intermediate 1. The structural formula of intermediate 1 is as follows: S2. Under inert gas protection, m-chloroperoxybenzoic acid was added to dichloromethane, and intermediate 1 was added at 5-10°C. After reaction, the mixture was purified to obtain intermediate 2. The structural formula of intermediate 2 is as follows: S3. The intermediate 2 is subjected to a cycloaddition reaction with CO2 under the action of bis(triphenylphosphine)ammonium chloride, and after purification, the crosslinking agent is obtained.

5. The high-stability anti-reflective coating according to claim 4, wherein In step S1, the molar ratio of magnolol, 3,7,11-trimethyldodecane-3-ol, triphenylphosphine, di-tert-butyl azodicarbonate, diethylene glycol, and diethyl azodicarbonate is 1:(1-1.2):(1.1-1.3):(1.1-1.3):(1.1-1.3):(1.1-1.3); the heating reaction is carried out at a temperature of 70-75℃ for 12-18 hours; the cooling reaction is carried out at a temperature of 20-25℃ for 6-10 hours.

6. The high stability anti-reflective coating of claim 4, wherein, In step S2, the molar ratio of intermediate 1 to m-chloroperoxybenzoic acid is 1:(3-4); the reaction temperature is 20-25℃ and the reaction time is 8-12h.

7. The high stability anti-reflective coating of claim 4, wherein, In step S3, the molar ratio of intermediate 2 and bis(triphenylphosphine)ammonium chloride is 1:(0.005-0.015); the cycloaddition reaction is carried out in an autoclave at 110-130°C for 48-72 hours with 40 bar carbon dioxide as the reaction gas.

8. The high stability anti-reflective coating of claim 1, wherein, The solvent is propylene glycol methyl ether acetate or methyl 2-hydroxyisobutyrate.

9. A method for preparing a highly stable antireflective coating according to any one of claims 1-8, characterized in that, Includes the following steps: Simply mix the matting resin, crosslinking agent, and solvent thoroughly.

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