Synthesis of a positive chemical amplification photoresist resin, and preparation method and application thereof

Abstract

This invention provides a positive chemical amplification photoresist resin synthesis method and its application. The positive chemical amplification photoresist resin has a specific structure, and its synthesis method involves obtaining a polymer with the corresponding structure through active anionic polymerization. This resin can improve problems such as tilted sidewalls and low resolution in photoresist after development, thereby meeting higher photolithography requirements.

Description

Technical Field

[0001] This invention relates to the field of photoresist technology, specifically to the synthesis, preparation method, and application of a positive chemical amplification photoresist resin. Background Technology

[0002] Photoresist is one of the most important types of photolithography materials, also known as photoresist. Its solubility changes significantly under visible light, ultraviolet light, or electron beams. Based on the change in solubility in the developer after exposure, photoresists can be divided into positive and negative photoresists. In positive photoresists, the polymer chains undergo chemical reactions such as degradation or deprotection of functional groups in the exposed areas, increasing their solubility in the developer and ultimately forming a pattern on the substrate identical to the photomask. In contrast, in negative photoresists, the polymer chains cross-link and become insoluble in the exposed areas, while the unexposed areas dissolve in the developer, resulting in a pattern opposite to the photomask pattern.

[0003] Currently, the exposure wavelengths in photolithography have been shortened from 436 nm for ultraviolet g-lines and 365 nm for i-lines to 248 nm for KrF excimer lasers and 193 nm for ArF excimer lasers. However, the diazonoquinone-phenolic resin commonly used in g-lines / i-lines cannot meet the requirements of KrF photoresists. One reason is that compared to g-line / i-line light sources, KrF light sources have a lower exposure dose, thus requiring higher sensitivity; while the quantum yield of diazonoquinone-phenolic resin photoresists is only 0.2–0.3. In addition, this type of resin has strong absorption under KrF light sources, making it difficult to meet the requirements for light transparency.

[0004] To address these issues, IBM optimized the resin structure and introduced the concept of Chemical Amplified (CA), improving the resolution and sensitivity of photoresists. Chemically amplified photoresists mainly consist of resin, dissolution inhibitors, alkaline quenchers, photochemical acid generators (PAGs), and solvents. During photolithography, PAGs decompose upon exposure to produce acid. The resulting acid acts as a catalyst, continuously catalyzing the chemical reactions of acid-indestructible groups within the resin structure, effectively enhancing the sensitivity of the photoresist.

[0005] However, most commonly used KrF photoresists are obtained through free radical polymerization, resulting in a wide molecular weight distribution (typically greater than 1.5). Consequently, these photoresists exhibit sidewall tilting after exposure and have low resolution, making them unsuitable for high-end photolithography processes. Summary of the Invention

[0006] One of the objectives of this invention is to provide a positive chemical amplification photoresist resin, which can improve problems such as tilted sidewalls and low resolution of photoresist after development, so as to meet higher photolithography requirements.

[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0008] A positive chemical amplification photoresist resin, wherein the resin is a polymer having the general structural formula (II):

[0009]

[0010] Wherein, a, b, and c are the molar percentages of each component, and a + b + c = 1; R1 contains one of hydrogen, methyl, and ethyl, preferably hydrogen; R2 contains one of tert-butyl, methyl, ethyl, and benzyl, preferably tert-butyl; Ar contains one of phenyl, thiophene, furanyl, thiazolyl, selenene, carbazole, pyrrole, and pyridinyl, preferably phenyl, thiophene, and furanyl; R4 contains C1-C8 alkyl and / or alkoxy groups; wherein, in the polymer, 0.3 ≤ a ≤ 0.9, 0 < b ≤ 0.5, and 0 < c ≤ 0.5; preferably 0.5 ≤ a ≤ 0.8, 0 < b ≤ 0.3, and 0 < c ≤ 0.3.

[0011] The inventors discovered that using anionic polymerization instead of free radical polymerization results in polymers with a more uniform molecular weight distribution and more consistent exposure response, which helps to improve the aforementioned problems.

[0012] In one embodiment of the present invention, the weight-average molecular weight of the polymer is ≥1000, preferably 5000 to 30000.

[0013] In one embodiment of the present invention, the polymer has a molecular weight distribution range of 1.0 to 1.5, preferably 1.0 to 1.3, and more preferably 1.0 to 1.2.

[0014] Another object of the present invention is to provide a method for preparing a positive chemical amplification photoresist resin.

[0015] A method for preparing a positive chemical amplification photoresist resin, wherein the method prepares the above-mentioned resin, and the method comprises: monomers represented by formulas (III), (IV) and (V) are subjected to anionic solution polymerization initiated by an initiator to obtain a polymer resin.

[0016]

[0017] Wherein, R1 contains one of hydrogen, methyl, and ethyl, preferably hydrogen; R2 contains one of tert-butyl, methyl, ethyl, and benzyl, preferably tert-butyl; and R3 contains one of alkyl, aryl, and silyl.

[0018] In one embodiment of the present invention, the preparation method involves a reaction in the presence of a salt; preferably, the salt has the following general structural formula:

[0019] R5-OLi type (VI)

[0020] R5 contains one of alkyl, alkylacyl, aryl, and arylacyl groups.

[0021] In one embodiment of the present invention, the initiator structure is as follows:

[0022]

[0023] Wherein, Ar contains one of phenyl, thiophene, furanyl, thiazolyl, selenene, carbazolyl, pyrrole, and pyridinyl, preferably one of phenyl, thiophene, and furanyl; X contains Li and / or MgBr, preferably Li; R4 contains C1-C8 alkyl and / or alkoxy groups.

[0024] In one embodiment of the present invention, the polymerization temperature is 0 to -80°C, and the polymerization mass concentration is 10% to 20%.

[0025] Another object of the present invention is to provide a use of a photoresist resin.

[0026] Use of a photoresist resin, wherein the resin is the resin described above, or the resin prepared by the above preparation method, and the resin is used to prepare a positive chemical amplification photoresist.

[0027] Another object of the present invention is to provide a photoresist.

[0028] A photoresist, wherein the photoresist is made from the resin described above, or from a resin prepared by the method described above, and the photoresist is prepared from raw materials comprising the photoresist resin, a photoacid generator, a solvent, an alkali, a surfactant, and a small molecule dissolution inhibitor; preferably, the mass percentage of each component, based on the total mass of the photoresist, is as follows: resin 3%–33%, photoacid generator 0.01%–1%, solvent 65%–96%, alkali 0.01%–1%, surfactant 0.01%–0.1%, and small molecule dissolution inhibitor 0.01%–0.5%.

[0029] In one specific embodiment, the photoacid-generating agent comprises at least one of onium salts, triazines, sulfonyldiazomethanes, oxime esters, and nitrobenzyl sulfonates; wherein the onium salt photoacid-generating agent includes, but is not limited to, triphenylthionium perfluorobutanesulfonate, triphenylthionium o-trifluoromethanesulfonate, triphenylthionium trifluoromethanesulfonate, di-tert-butylphenyliodomonium perfluorobutanesulfonate, triphenylthionium 2,4,6-triisopropylbenzenesulfonate, and di-tert-butylphenyliodomonium o-trifluoromethanesulfonate. Photoacid-producing agents include salts such as di-tert-butylphenyl iodonium trifluoromethanesulfonate and di-tert-butylphenyl iodonium 2,4,6-triisopropylbenzenesulfonate; triazines such as 2,4,6-tris(trichloromethyl)-1,3,5-triazine; sulfonyl diazomethane photoacid-producing agents including but not limited to bis(p-toluenesulfonyl)diazomethane, bis(cyclohexyl)diazomethane, bis(tert-butylsulfonyl)diazomethane, and bis(isopropanesulfonyl)diazomethane; oxime ester photoacid-producing agents such as PAG 203; and nitrobenzyl sulfonate photoacid-producing agents such as 2,6-dinitrobenzyl p-toluenesulfonate. The preferred onium salt is a sulfonyl diazomethane; more preferably, it is at least one of perfluorobutyrate triphenylthionium salt, o-trifluoromethanesulfonium salt, perfluorobutyrate di-tert-butylphenyliodoonium salt, o-trifluoromethanesulfonium salt, bis(p-toluenesulfonyl)diazomethane, and bis(cyclohexanesulfonyl)diazomethane. The above raw materials and their dosages are commonly used in the art.

[0030] In one specific embodiment, the solvent comprises at least one of ketone solvents, polyols and their derivatives, alkyl ethers, cyclic solvents, ester solvents, and amide solvents; wherein, ketone solvents include cyclohexanone, polyols and their derivatives include diethylene glycol monomethyl ether, alkyl ethers include propylene glycol monomethyl ether, cyclic solvents include γ-butyrolactone, ester solvents include propylene glycol monomethyl ether acetate, and amide solvents include N,N-dimethylformamide. Preferably, at least one of ethyl lactate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, γ-butyrolactone, cyclohexanone, and methyl 2-hydroxyisobutyrate is used. The above raw materials and their amounts are commonly used in the art.

[0031] In one specific implementation, the alkali comprises trioctylamine, triethanolamine, triethylamine, tetrabutylammonium hydroxide, etc. The above-mentioned raw materials and their amounts are commonly used in the art.

[0032] In one specific embodiment, the surfactant comprises a nonionic surfactant, such as FC4430. The above-mentioned raw materials and their amounts are commonly used in the art.

[0033] In one specific implementation, the small molecule dissolution inhibitor comprises bisphenol A, such as bisphenol A di-tert-butyl ether. The above-mentioned raw materials and their dosages are commonly used in the art.

[0034] Another object of the present invention is to provide an initiator.

[0035] An initiator, used in the resin described above, or in the resin prepared by the above preparation method, wherein the initiator has the following structure:

[0036]

[0037] Wherein, Ar contains one of phenyl, thiophene, furanyl, thiazolyl, selenene, carbazolyl, pyrrole, and pyridinyl, preferably one of phenyl, thiophene, and furanyl; X contains Li and / or MgBr, preferably Li; R4 contains C1-C8 alkyl and / or alkoxy groups.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] This invention yields a resin via active anionic polymerization. Compared to conventional free radical polymerized resins, the resulting resin exhibits a more uniform molecular weight distribution (PDI less than 1.50). Photoresists prepared using this resin show reduced edge roughness (less than 10 nm) and possess high contrast and excellent etching resistance, making them suitable for forming micron- or nanometer-scale patterns in integrated circuits or for applications in optoelectronic products and other fields. Attached Figure Description

[0040] Figure 1 The GPC spectra of resins A-1, A-2 and A-3 prepared in Examples 1-3 of this invention are shown. Detailed Implementation

[0041] To better understand the technical solution of the present invention, the following embodiments will further illustrate the method provided by the present invention. However, the present invention is not limited to the listed embodiments, but should also include any other well-known modifications within the scope of the claims of the present invention.

[0042] The main raw materials used in the following examples are from the following sources:

[0043] Methoxystyrene (500mL, ≥99%), 4-n-butylbenzyl bromide (50mL, ≥97%), 2-bromomethyl-5-hexylthiophene (50mL, ≥96%), 4-methoxybenzyl bromide (50mL, ≥90%), tert-butoxystyrene (500mL, ≥99%), styrene (500mL, ≥99%), tert-butyl acrylate (500mL, ≥99%), methyl methacrylate (500mL, ≥99%), azobisisobutyronitrile (100g, ≥95%), lithium methoxide (25g, ≥98%), lithium acetate (25g, ≥99%), and lithium tert-butoxide (25g, ≥99%) were all sourced from Aladdin Biochemical Technology Co., Ltd.

[0044] Magnesium metal (100g, ≥99%), lithium metal (100g, ≥99%), bisphenol A di-tert-butyl ether (50g, ≥99%), propylene glycol monomethyl ether acetate (PGMEA, 500mL, ≥99%), propylene glycol monomethyl ether (PGME, 500mL, ≥99%), isopropanol (IPA, 500mL, ≥99.8%), triphenylthionium perfluorobutanesulfonate (10g, ≥99%), and surfactant FC4430 (10g, ≥99%) were purchased from Inokai Technology Co., Ltd.

[0045] The analysis methods involved in the embodiments are as follows:

[0046] NMR: Instrument: Bruker 300M; Deuteration reagent: chloroform or dimethyl sulfoxide; Test temperature: room temperature.

[0047] GPC: Instrument: Shimadzu LC-ADXR-2, Standard: PS, prepared as 1% THF solution, Test temperature: 35℃, Flow rate: 1mL / min.

[0048] LWR Testing: Gaseous HMDS was deposited onto the wafer substrate surface in the HMDS chamber of a spin coater. Photoresist was spin-coated onto the HMDS-pretreated silicon wafer at 2500 rpm to form a film. The film was then baked on a hot plate at 120°C for 90 seconds, cooled to room temperature in a cold plate chamber, and then exposed on an exposure machine at a wavelength of 248 nm and an exposure intensity of 50 mJ / cm². 2 After exposure, the sample was baked on a hot plate at 110°C for 90 seconds, then developed in 2.38% TMAH developer for 60 seconds, and finally dried. The photolithography results were then examined under an electron microscope.

[0049] Synthesis example 1

[0050] Synthesis of initiator I-1

[0051]

[0052] 16.4 g (72 mmol) of 4-n-butylbenzyl bromide and 30 mL of anhydrous hexane were added to a dropping funnel and mixed thoroughly. A 200 mL puff flask was purged with nitrogen three times, and then 50 mL of anhydrous hexane and 1 g of lithium metal (144 mmol) were added. Under nitrogen protection, the solution was slowly added dropwise to the puff flask using a dropping funnel over a period of 30 min. The reaction was stopped by stirring and reflux for 4 hours. The puff flask was then sealed with a stopper and stored in a refrigerator. The concentration of I⁻ was determined to be 0.7 mol / L by titration. The 1H NMR peak distribution of the titration product was δ 7.06–7.10 (m, 4H), 2.57 (t, 2H), 2.32 (s, 3H), 1.52–1.61 (m, 2H), 1.30–1.39 (m, 2H), 0.92 (t, 3H).

[0053] Synthesis example 2

[0054] Synthesis of initiator I-2

[0055]

[0056] 22.6 g (87 mmol) of 2-bromomethyl-5-hexylthiophene and 35 mL of anhydrous hexane were added to a dropping funnel and mixed thoroughly. A 200 mL puff flask was purged with nitrogen three times, and then 55 mL of anhydrous hexane and 1.2 g of lithium metal (173 mmol) were added. Under nitrogen protection, the solution was slowly added dropwise to the puff flask using a dropping funnel over a period of 30 minutes. The reaction was stopped by stirring and reflux for 4 hours. The puff flask was sealed with a stopper and stored in a refrigerator. The concentration of I₂ was determined to be 0.75 mol / L by titration. The NMR values ​​of the titration products were δ 6.80 (d, 2H), 6.55 (d, 2H), 2.81 (t, 2H), 2.37 (s, 3H), 1.68 (m, 2H), 1.28–1.30 (m, 6H), and 0.90 (t, 3H).

[0057] Synthesis example 3

[0058] Synthesis of initiator I-3

[0059]

[0060] Weigh 1.7 g (70 mmol) of magnesium shavings into a two-necked flask and purge with nitrogen at least three times. Then, open the rubber stopper and quickly add four grains of elemental iodine, purging again rapidly. Add 20 mL of tetrahydrofuran using a syringe; the solution turns reddish-brown. Transfer the system to a 70°C oil bath and heat with stirring briefly; the solution turns yellowish-green. Dilute 14.1 g (70 mmol) of 4-methoxybenzyl bromide in 50 mL of tetrahydrofuran. Under nitrogen protection, slowly add the solution dropwise to the reaction flask using a dropping funnel over 30 minutes. Continue stirring and reflux for 4 hours to stop the reaction. Seal the flask with a flap stopper and store in a refrigerator. The I-3 concentration was determined to be 0.80 mol / L by titration, and the NMR values ​​of the titration products were δ 7.09 (d, 2H), 6.81 (d, 2H), 3.72 (s, 3H), and 2.24 (s, 3H).

[0061] Example 1

[0062] Synthesis of chemically amplified resin A-1:

[0063]

[0064] A 500 mL puff flask was purged with nitrogen three times. 150 mL of anhydrous tetrahydrofuran was added, followed by a mixture of methoxystyrene (14.76 g, 110 mmol), styrene (4.11 g, 39 mmol), and tert-butyl acrylate (1.01 g, 7.9 mmol), bringing the total reaction concentration to 13%. Lithium methoxide (0.2 g, 5.3 mmol) was then added, and the mixture was stirred to promote dissolution. After complete dissolution, the system was placed in a -80°C cold bath and kept at this temperature for at least 10 minutes. I-1 solution (6.4 mL, 4.5 mmol) was rapidly added to the system using a syringe to initiate the reaction. The reaction was maintained at this temperature for at least 1 hour. After the reaction was complete, 1 mL of degassed methanol was added to terminate the reaction. The reaction solution was then poured into 1.5 L of methanol to precipitate the precipitate. After filtration, the filter cake was redissolved in 100 mL of tetrahydrofuran, and then poured into 1.5 L of methanol to precipitate. The resulting filter cake was rinsed with 500 mL of methanol and then placed in a vacuum drying oven for overnight vacuum drying.

[0065] The above resin was placed in a three-necked flask and purged with nitrogen. Then, 50 mL of tetrahydrofuran was added to dissolve the resin. Next, 15 g of concentrated hydrochloric acid was added. The reaction flask was placed in an oil bath at 55°C and heated for 5 hours. After the reaction, the reaction solution was poured into 1 L of deionized water to precipitate. After filtration, the filter cake was redissolved in 50 mL of tetrahydrofuran, poured into 1 L of deionized water again to precipitate, and the resulting filter cake was rinsed with 200 mL of deionized water and then vacuum dried overnight in a vacuum drying oven to obtain 17.2 g of ternary copolymer resin A-1, with a yield of 94%. GPC testing of resin A-1 showed that its weight-average molecular weight M... w =5070, PDI=1.19.

[0066] Example 2

[0067] Synthesis of chemically amplified resin A-2:

[0068]

[0069] A 500 mL puff flask was purged with nitrogen three times. 150 mL of anhydrous tetrahydrofuran was added, followed by a mixture of tert-butoxystyrene (13.75 g, 78 mmol), styrene (3.26 g, 31 mmol), and tert-butyl acrylate (6 g, 47 mmol), bringing the total reaction concentration to 14%. Lithium acetate (0.3 g, 7.9 mmol) was then added, and the mixture was stirred to promote dissolution. After complete dissolution, the system was placed in a -80°C cold bath for at least 10 minutes. I-2 solution (4 mL, 3 mmol) was rapidly added to the system using a syringe to initiate the reaction. The reaction was maintained at this temperature for at least 1 hour. After the reaction was complete, 1 mL of degassed methanol was added to terminate the reaction. The reaction solution was poured into 1.5 L of methanol to precipitate. After filtration, the filter cake was redissolved in 100 mL of tetrahydrofuran, poured into 1.5 L of methanol again to precipitate, and the resulting filter cake was rinsed with 500 mL of methanol and then vacuum dried overnight in a vacuum drying oven.

[0070] The above resin was placed in a three-necked flask and purged with nitrogen. Then, 50 mL of tetrahydrofuran was added to dissolve the resin. Next, 15 mL of concentrated hydrochloric acid solution was added. The reaction flask was placed in an oil bath at 55°C and heated for 5 hours. After the reaction was complete, the reaction solution was poured into 1 L of deionized water to precipitate. After filtration, the filter cake was redissolved in 50 mL of tetrahydrofuran, poured into 1 L of deionized water again to precipitate, and the resulting filter cake was rinsed with 200 mL of deionized water and then vacuum dried overnight in a vacuum drying oven to obtain 17.9 g of ternary copolymer resin A-2, with a yield of 96%. GPC testing of resin A-2 showed that its weight-average molecular weight M... w =10350, PDI=1.16.

[0071] Example 3

[0072] Synthesis of chemically amplified resin A-3:

[0073]

[0074] A 500 mL puff flask was purged with nitrogen three times. 150 mL of anhydrous tetrahydrofuran was added, followed by a mixture of tert-butoxystyrene (25 g, 140 mmol), styrene (1.89 g, 18 mmol), and methyl methacrylate (2.17 g, 17 mmol), bringing the overall reaction concentration to 18%. Lithium tert-butoxide (0.34 g, 4.2 mmol) was then added, and the mixture was stirred to promote dissolution. After complete dissolution, the system was placed in a -80°C cold bath and kept at this temperature for at least 10 minutes. Using a syringe, 1.1 mL (0.9 mmol) of I-3 solution was rapidly added to the above system to initiate the reaction. The reaction was maintained at this temperature for at least 1 hour. After the reaction was complete, 1 mL of degassed methanol was added to terminate the reaction. The reaction solution was then poured into 1.5 L of methanol to precipitate the precipitate. After filtration, the filter cake was redissolved in 100 mL of tetrahydrofuran, and then poured into 1.5 L of methanol to precipitate. The resulting filter cake was rinsed with 500 mL of methanol and then placed in a vacuum drying oven for overnight vacuum drying.

[0075] The above resin was placed in a three-necked flask and purged with nitrogen. Then, 50 mL of tetrahydrofuran was added to dissolve the resin. Next, 15 mL of concentrated hydrochloric acid solution was added. The reaction flask was placed in an oil bath at 55°C and heated for 5 hours. After the reaction was complete, the reaction solution was poured into 1 L of deionized water to precipitate. After filtration, the filter cake was redissolved in 50 mL of tetrahydrofuran, poured into 1 L of deionized water again to precipitate, and the resulting filter cake was rinsed with 200 mL of deionized water and then vacuum dried overnight in a vacuum drying oven to obtain 20.2 g of ternary copolymer resin A-3, with a yield of 96%. GPC testing of resin A-3 showed that its weight-average molecular weight M... w =27433, PDI=1.13.

[0076] Comparative Example 1

[0077] Compared with Example 1, the only difference is that B-1 resin was synthesized using a free radical polymerization method.

[0078] Synthesis of chemically amplified resin B-1

[0079]

[0080] A 250 mL three-necked flask was purged with nitrogen three times, and 70 mL of PGMEA was added. Heating was initiated. Methoxystyrene (14.76 g, 110 mmol), styrene (4.11 g, 39 mmol), tert-butyl acrylate (1.01 g, 7.9 mmol), and azobisisobutyronitrile (3.01 g) were dissolved in 5 mL of PGMEA. After reflux, the monomer solution was added dropwise to the three-necked reaction flask over 3 hours. The reaction was continued for another 5 hours after the addition was complete. After the reaction was complete, 10 mL of methanol was added to quench the reaction. The reaction solution was poured into 1.5 L of methanol to precipitate. After filtration, the filter cake was redissolved in 100 mL of tetrahydrofuran, poured into 1.5 L of methanol again to precipitate, and the resulting filter cake was washed with 500 mL of methanol and then vacuum dried overnight in a vacuum drying oven.

[0081] The above resin was placed in a three-necked flask and purged with nitrogen. Then, 50 mL of tetrahydrofuran was added to dissolve the resin. Next, 15 mL of concentrated hydrochloric acid solution was added. The reaction flask was placed in an oil bath at 55°C and heated for 5 hours. After the reaction was complete, the reaction solution was poured into 1 L of deionized water to precipitate. After filtration, the filter cake was redissolved in 50 mL of tetrahydrofuran, poured into 1 L of deionized water again to precipitate, and the resulting filter cake was rinsed with 200 mL of deionized water and then vacuum dried overnight in a vacuum drying oven to obtain 15.6 g of ternary copolymer resin B-1, with a yield of 85%. GPC testing of resin B-1 showed that its weight-average molecular weight M... w =6020, PDI=1.82.

[0082] Comparative Example 2

[0083] Compared with Example 2, the only difference is that B-2 resin was synthesized using a free radical polymerization method.

[0084] Synthesis of chemically amplified resin B-2

[0085]

[0086] A 250 mL three-necked flask was purged with nitrogen three times, and 70 mL of PGMEA was added. Heating was initiated. Tert-butoxystyrene (13.75 g, 78 mmol), styrene (3.26 g, 31 mmol), tert-butyl acrylate (6 g, 47 mmol), and azobisisobutyronitrile (1 g) were dissolved in 5 mL of PGMEA. After reflux, the monomer solution was added dropwise to the three-necked reaction flask over a period of 3 hours. The reaction was continued for another 5 hours after the addition was complete. After the reaction was complete, 10 mL of methanol was added to quench the reaction. The reaction solution was poured into 1.5 L of methanol to precipitate. After filtration, the filter cake was redissolved in 100 mL of tetrahydrofuran, and then poured into 1.5 L of methanol again to precipitate. The resulting filter cake was washed with 500 mL of methanol and then vacuum dried overnight in a vacuum drying oven.

[0087] The above resin was placed in a three-necked flask and purged with nitrogen. Then, 50 mL of tetrahydrofuran was added to dissolve the resin. Next, 15 mL of concentrated hydrochloric acid solution was added. The reaction flask was placed in an oil bath at 55°C and heated for 5 hours. After the reaction, the reaction solution was poured into 1 L of deionized water to precipitate. After filtration, the filter cake was redissolved in 50 mL of tetrahydrofuran, poured into 1 L of deionized water again to precipitate, and the resulting filter cake was rinsed with 200 mL of deionized water and then vacuum dried overnight in a vacuum drying oven to obtain 15.0 g of ternary copolymer resin B-2, with a yield of 80%. GPC testing of resin B-2 showed that its weight-average molecular weight M... w =12043, PDI=1.93.

[0088] Comparative Example 3

[0089] Compared with Example 3, the only difference is that B-3 resin was synthesized using a free radical polymerization method.

[0090] Synthesis of chemically amplified resin B-3

[0091]

[0092] A 250 mL three-necked flask was purged with nitrogen three times, and 70 mL of IPA was added. Heating was initiated. Tert-butoxystyrene (25 g, 140 mmol), styrene (1.89 g, 18 mmol), methyl methacrylate (2.17 g, 17 mmol), and azobisisobutyronitrile (0.30 g) were dissolved in 5 mL of LGMEA. After reflux, the monomer solution was added dropwise to the three-necked flask over 3 hours. The reaction was continued for another 5 hours after the addition was complete. After the reaction was complete, 10 mL of methanol was added to quench the reaction. The reaction solution was poured into 1.5 L of methanol to precipitate. After filtration, the filter cake was redissolved in 100 mL of tetrahydrofuran, poured into 1.5 L of methanol again to precipitate, and the resulting filter cake was washed with 500 mL of methanol and then vacuum dried overnight in a vacuum drying oven.

[0093] The above resin was placed in a three-necked flask and purged with nitrogen. Then, 50 mL of tetrahydrofuran was added to dissolve the resin. Next, 15 mL of concentrated hydrochloric acid solution was added. The reaction flask was placed in an oil bath at 55°C and heated for 5 hours. After the reaction was complete, the reaction solution was poured into 1 L of deionized water to precipitate. After filtration, the filter cake was redissolved in 50 mL of tetrahydrofuran, poured into 1 L of deionized water again to precipitate, and the resulting filter cake was rinsed with 200 mL of deionized water and then vacuum dried overnight in a vacuum drying oven to obtain 18.5 g of ternary copolymer resin B-3, with a yield of 88%. GPC testing of resin B-3 showed that its weight-average molecular weight M... w =28900, PDI=1.88.

[0094] The GPC spectra of the resins prepared in Examples 1-3 of this invention are as follows: Figure 1 As shown in the figure, the polymer PDI prepared using this method is smaller and has a narrower distribution.

[0095] To verify the effectiveness of the present invention, photolithography and morphology evaluation were performed using the photoresists of Examples 4-6 and Comparative Examples 4-6. The photoresist composition is shown in Table 2; the photolithography test results are shown in Table 3.

[0096] Table 2 Photoresist Composition Table

[0097]

[0098]

[0099] Wherein: PAG is triphenylthionium salt of o-trifluoromethanesulfonate; S is PGMEA / PGME = 3 / 1; D is bisphenol A ditert-butyl ether.

[0100] Table 3 shows the test results of the above photoresist.

[0101] Photoresist LWR(nm) Appearance Example 4 8.5 rectangle Example 5 8.9 rectangle Example 6 7.9 rectangle Comparative Example 4 15.2 Side wall tilt Comparative Example 5 17.5 Side wall tilt Comparative Example 6 18.3 Side wall tilt

[0102] The results above show that the ternary copolymer resin prepared by this invention has a narrow molecular weight distribution and relatively uniform molecular chain length. Therefore, the photoresist prepared from the resin synthesized by this invention exhibits better morphology during photolithography and has the advantage of low roughness.

[0103] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as limiting the present invention. Those skilled in the art will understand that modifications or adjustments can be made to the present invention based on the teachings of this specification. These modifications or adjustments should also be within the scope defined by the claims of the present invention.

Claims

1. A positive chemically amplified photoresist resin characterized by comprising: The resin is a polymer having the general structural formula (II): Wherein, a, b, and c represent the molar percentages of each component, and a + b + c = 1; R1 contains one of hydrogen, methyl, and ethyl, preferably hydrogen; R2 contains one of tert-butyl, methyl, ethyl, and benzyl, preferably tert-butyl; Ar contains one of phenyl, thiophene, furanyl, thiazolyl, selenophene, carbazole, pyrrole, and pyridinyl, preferably phenyl, thiophene, and furanyl; R4 contains C1-C8 alkyl and / or alkoxy groups. Wherein, in the polymer, 0.3≤a≤0.9, 0<b≤0.5, 0<c≤0.5; preferably 0.5≤a≤0.8, 0<b≤0.3, 0<c≤0.

3.

2. The resin according to claim 1, characterized in that, The weight-average molecular weight of the polymer is ≥1000, preferably 5000 to 30000; And / or, the molecular weight distribution of the polymer is in the range of 1.0 to 1.5, preferably 1.0 to 1.3, and more preferably 1.0 to 1.

2.

3. A method for preparing a positive chemical amplification photoresist resin, wherein the preparation method prepares the resin according to claim 1 or 2, characterized in that, The method is as follows: the monomers shown in formulas (III), (IV) and (V) are polymerized in anionic solution using an initiator to obtain polymer resins. Wherein, R1 contains one of hydrogen, methyl, and ethyl, preferably hydrogen; R2 contains one of tert-butyl, methyl, ethyl, and benzyl, preferably tert-butyl; and R3 contains one of alkyl, aryl, and silyl.

4. The preparation method according to claim 3, characterized in that, The preparation method involves a reaction in the presence of salt; Preferably, the salt has the following general structural formula: R5-OLi type (VI) R5 contains one of alkyl, alkylacyl, aryl, and arylacyl groups.

5. The preparation method according to claim 3 or 4, characterized in that, The initiator has the following structure: Wherein, Ar contains one of phenyl, thiophene, furanyl, thiazolyl, selenene, carbazolyl, pyrrole, and pyridinyl, preferably one of phenyl, thiophene, and furanyl; X contains Li and / or MgBr, preferably Li; R4 contains C1-C8 alkyl and / or alkoxy groups.

6. The preparation method according to any one of claims 3-5, characterized in that, The polymerization temperature is 0 to -80°C, and the polymerization mass concentration is 10% to 20%.

7. Use of a photoresist resin, wherein the resin is the resin according to claim 1 or 2, or the resin prepared by any one of claims 3 to 6, and the resin is used to prepare a positive chemical amplification photoresist.

8. A photoresist, wherein the photoresist is made of the resin according to claim 1 or 2, or a resin prepared by any one of claims 3 to 6, characterized in that, The photoresist is prepared from raw materials comprising the photoresist resin, a photoacid generator, a solvent, an alkali, a surfactant, and a small molecule dissolution inhibitor. Preferably, based on the total mass of the photoresist, the mass percentage of each component is as follows: resin 3%–33%, photoacid generator 0.01%–1%, solvent 65%–96%, alkali 0.01%–1%, surfactant 0.01%–0.1%, and small molecule dissolution inhibitor 0.01%–0.5%.

9. An initiator used in the resin of claim 1 or 2, or in a resin prepared by the preparation method of any one of claims 3 to 6, wherein the initiator has the following structure: in, Ar contains one of phenyl, thiophene, furanyl, thiazolyl, selenophene, carbazole, pyrrole, and pyridinyl, preferably one of phenyl, thiophene, and furanyl; X contains Li and / or MgBr, preferably Li; R4 contains C1-C8 alkyl and / or alkoxy groups.

Images