Adamantane sulfonium salt photoacid generator as well as preparation method and application thereof

Abstract

The invention relates to the technical field of acid generator preparation, in particular to an adamantane sulfonium salt photoacid generator as well as a preparation method and application thereof. The preparation method comprises the following steps: in an organic solvent, carrying out esterification reflux reaction on 1-adamantane methanol, difluorobromoacetic acid and methanesulfonic acid to obtain a bromodifluoroacetate product containing adamantane; carrying out a sulfonation dehalogenation reaction on the bromodifluoroacetate product by using sodium hydrosulfite and sodium bicarbonate to obtain sulfinate containing adamantane; the preparation method comprises the following steps: carrying out oxidation reaction on sulfinate by using an oxidizing agent to obtain adamantane-containing sulfonate; in a mixed system of dichloromethane and water, sulfonate and (4-tert-butylphenyl) diphenyl sulfonium chloride salt are subjected to ion exchange, and the adamantane sulfonium salt photoacid generator is obtained. According to the preparation method, the yield of the adamantane sulfonium salt photoacid generator can be systematically improved by optimizing parameters and conditions of an esterification reflux reaction, a sulfonation dehalogenation reaction, an oxidation reaction and ion exchange.

Description

Technical Field

[0001] This application relates to the field of acid-generating agent preparation technology, and in particular to an adamantane-based sulfonium salt photo-induced acid-generating agent, its preparation method, and its application. Background Technology

[0002] Photoresist, also known as photoresist, is a photosensitive organic compound. It is a core material in semiconductor manufacturing, display panels, and printed circuit boards (PCBs) because it transfers fine patterns from a photomask to the surface of a substrate (such as a silicon wafer or glass substrate) through a photochemical reaction. Currently, the core functions of photoresist include: (1) pattern transfer: accurately replicating the photomask pattern onto the substrate surface through exposure and development; and (2) protection: protecting the underlying material during subsequent etching or ion implantation processes. The main components of photoresist include approximately 50% resin, approximately 35% monomers, approximately 15% photoinitiators (such as photoacid generators), and additives. Currently, the performance indicators of photoresist include resolution, contrast ratio, sensitivity, and resistivity, which directly affect chip integration and display panel color accuracy. Among the various components of photoresist, photoacid generator (PAG) is the core functional component. Its mechanism of action is as follows: during the exposure phase of the photoresist (e.g., ultraviolet light, deep ultraviolet DUV, or extreme ultraviolet EUV), the photoacid generator absorbs light energy, undergoes a photochemical reaction, and generates an acid (e.g., strong acid H+). This acid can act as a catalyst during the subsequent baking process, triggering and catalyzing the deprotection or cross-linking reactions of the resin (e.g., poly(p-hydroxystyrene) derivatives) in the photoresist, causing changes in the resin's chemical structure and thus altering the photoresist's solubility in the developer.

[0003] Common photoacid generators are mainly classified into onium salts, nitrobenzyl esters, diazonoquinones, and nonionic PAGs (including sulfonates and sulfonate imides) based on their chemical structures. Among these photoacid generators, onium salts are often used in practical applications due to their high photosensitivity, high thermal stability, and sufficient acid production. Among onium salts, sulfonium salts and iodonium salts stand out, with sulfonium salt photoacid generators being more stable than iodonium salt photoacid generators. Therefore, sulfonium salt photoacid generators are currently the focus of research and development.

[0004] 2-(((3R,5R,7R)-adamantane-1-yl)methoxy)-1,1-difluoro-2-oxoethane-1-sulfonate (4-(tert-butyl)phenyl)diphenylsulfonium salt is a novel sulfonium salt compound photoacid generator, but its preparation process is lengthy and the yield is low, which has limited the application of sulfonium salt compound photoacid generators. Summary of the Invention

[0005] This application provides an adamantane-based sulfonium salt photoacid generator, its preparation method, and its application, in order to solve the following technical problem: how to improve the yield of sulfonium salt compound photoacid generators.

[0006] In a first aspect, embodiments of this application provide a method for preparing an adamantane-based sulfonium salt photoacid-generating agent, the preparation method comprising: In an organic solvent, 1-adamantane methanol, difluorobromoacetic acid and methanesulfonic acid are subjected to an esterification reflux reaction to obtain a bromodifluoroacetic acid ester product containing adamantane. The bromodifluoroacetate product containing adamantane was subjected to a sulfinization dehalogenation reaction using sodium dithionite and sodium bicarbonate to obtain adamantane-containing sulfinate. The sulfinate containing adamantane is oxidized using an oxidizing agent to obtain a sulfonate containing adamantane. In a mixture of dichloromethane and water, the sulfonate containing adamantane and the (4-tert-butylphenyl)diphenyl sulfonium chloride are subjected to ion exchange to obtain an adamantane-based sulfonium salt photoacid-generating agent.

[0007] Optionally, the amount of 1-adamantane carboxylic acid n1, the amount of difluorobromoacetic acid n2, and the amount of methanesulfonic acid n3 satisfy the following: n1:n2:n3=1:(1.0 to 1.5):(0.05 to 0.1).

[0008] Optionally, the amount of sodium dithionite n4, the amount of sodium bicarbonate n5, and the amount of bromodifluoroacetate product n6 satisfy the following ratio: n4:n5:n6 = (1.0 to 1.5):(1.0 to 1.2):1.0.

[0009] Optionally, the mass m1 of the oxidant and the mass m2 of the bromodifluoroacetate product satisfy the following ratio: m1:m2 = (0.6 to 0.8):1.0.

[0010] Optionally, the amount of the sulfonate n7 and the amount of the (4-tert-butylphenyl)diphenylsulfonium chloride n8 satisfy: n7:n8 = (1.0 to 2.0):1.0.

[0011] Optionally, the esterification reflux reaction is carried out at a temperature of 75°C to 85°C for a duration of 2 hours to 4 hours; and / or The sulfonation dehalogenation reaction is carried out at a temperature of 55°C to 65°C for a duration of 2 hours to 4 hours; and / or The oxidation reaction is carried out at a temperature of 45°C to 55°C for a duration of 2 hours to 4 hours; and / or The oxidant is added at a temperature of -10°C to 10°C; and / or The ion exchange time is 2 to 4 hours.

[0012] Optionally, the bromodifluoroacetate product has the molecular structure shown in Formula 1: , Formula 1; and / or, The sulfinate has the molecular structural formula shown in Formula 2: , Equation 2; and / or, The sulfonate has the molecular structure shown in Formula 3: , Equation 3; and / or, The adamantane-based sulfonium salt photoacid-generating agent has the molecular structure shown in Formula 4: , Formula 4.

[0013] Optionally, the sulfonation dehalogenation reaction is carried out in a mixed solution of acetonitrile and ultrapure water, wherein the volume V1 of the acetonitrile and the volume V2 of the ultrapure water satisfy: (1.0 to 1.2):1.0; and / or The organic solvent includes any one of the following: dichloromethane, dichloroethane, chloroform, and acetonitrile.

[0014] Secondly, embodiments of this application provide an adamantane-based sulfonium salt photoacid generator, which is prepared by the preparation method described in the first aspect.

[0015] Thirdly, embodiments of this application provide a photoresist comprising the adamantane-based sulfonium salt photoacid generator described in the second aspect.

[0016] The technical solutions provided in this application have the following advantages compared with the prior art: This application provides a method for preparing an adamantane-based sulfonium salt photoacid-generating agent. The method first activates the carboxyl group of difluorobromoacetic acid using the strong protic acid of methanesulfonic acid, causing a dehydration esterification reaction between difluorobromoacetic acid and 1-adamantane-methanol, suppressing side reactions of the adamantane skeleton, and increasing the yield of the bromodifluoroacetic acid ester product. Then, under the alkaline conditions of sodium bicarbonate, sodium dithionite reacts with the C-Br bond of the bromodifluoroacetic acid ester product to form highly reactive sulfinate ions. These sulfinate ions... Through subsequent mild oxidation by an oxidant, the sulfonate can form a peroxide intermediate and eventually hydrolyze into a sulfonate with a stable adamantane structure. These sulfonates have high solubility in a mixture of dichloromethane and water. The selected (4-tert-butylphenyl)diphenyl sulfonium chloride also has high solubility in this mixture, which can promote the degree of interfacial ion pair exchange and drive the ion exchange equilibrium toward the adamantane sulfonium salt product, thereby ultimately increasing the yield of adamantane sulfonium salt. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic flowchart illustrating a method for preparing an adamantane-based sulfonium salt photoacid generator, provided for embodiments of this application; Figure 2 This is a schematic diagram illustrating the principle of a method for preparing an adamantane-based sulfonium salt photoacid-generating agent, as provided in an embodiment of this application. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] The range descriptions used in this application, such as numerical ranges and proportional ranges, include all possible sub-ranges and single numerical values ​​within that range. For example, the range descriptions of "1 to 6" or "1~6" cover all sub-ranges (such as 1 to 3, 2 to 5, etc.) and single numbers (such as 1, 2, 3, 4, 5, 6) between 1 and 6. Unless otherwise specified, the terms "comprising" and others used herein mean "including but not limited to"; relational terms such as "first" and "second" are used only to distinguish different entities or operations and do not imply an actual order or relationship; "and / or" indicates that multiple situations can exist individually or simultaneously; expressions such as "at least one," "multiple," and "at least one" refer to any combination of the corresponding objects, including combinations of single or multiple objects. The proportional relationships involved in this document, such as mass ratios and molar ratios, should be understood as the correspondence between the first and second terms of a proportional formula, according to the order of description. The raw materials, reagents, instruments, and equipment used herein can all be obtained by purchasing from the market or by existing methods.

[0022] Figure 1 An exemplary schematic diagram of a method for preparing an adamantane-based sulfonium salt photoacid generator provided in an embodiment of this application is shown. Figure 2 An exemplary schematic diagram illustrates the principle of a method for preparing an adamantane-based sulfonium salt photoacid generator provided in an embodiment of this application; like Figure 1 and Figure 2 As shown in the embodiments of this application, a method for preparing an adamantane-based sulfonium salt photoacid-generating agent is provided, the preparation method comprising: S1. In an organic solvent, 1-adamantane methanol, difluorobromoacetic acid and methanesulfonic acid are subjected to an esterification reflux reaction to obtain a bromodifluoroacetic acid ester product containing adamantane; S2. The bromodifluoroacetate product containing adamantane is subjected to a sulfinization dehalogenation reaction using sodium dithionite and sodium bicarbonate to obtain adamantane-containing sulfinate. S3. The sulfinate containing adamantane is oxidized using an oxidizing agent to obtain a sulfonate containing adamantane; S4. In a mixture of dichloromethane and water, the sulfonate containing adamantane and (4-tert-butylphenyl)diphenyl sulfonium chloride are subjected to ion exchange to obtain an adamantane-based sulfonium salt photoacid-generating agent.

[0023] It should be noted that the reaction product obtained from the esterification reflux reaction can be cooled to room temperature, and then 5% NaHCO3 (by mass) can be added to the reaction product and stirred for 30 min to obtain a mixture. The mixture is then extracted and separated, and deionized water is added to the organic layer obtained from the extraction and separation and stirred for 30 min. The extraction and separation are performed again to obtain an organic layer. The obtained organic layer is then dried by rotary evaporation to obtain a viscous oily substance, which is the bromodifluoroacetate product containing adamantane.

[0024] It should be noted that in this sulfinization dehalogenation reaction, the bromodifluoroacetate product needs to be dissolved in a mixed solution of acetonitrile and ultrapure water first, and then a mixture of sodium dithionite and sodium bicarbonate is added to carry out the sulfinization dehalogenation reaction. After the reaction yields a sulfinate solution, the resulting reaction solution is allowed to stand and separate into organic and aqueous phases. Acetonitrile is added to the aqueous phase for extraction again, and the extracted organic phase and the separated organic phases are combined to obtain a solution containing adamantane sulfinate.

[0025] It should be noted that during this oxidation reaction, ultrapure water needs to be added to the adamantane-containing sulfinate to ensure a 1:1 volume ratio of ultrapure water to acetonitrile in the sulfinate solution system. The oxidant is added under ice bath conditions to avoid the formation of peroxidation byproducts. Furthermore, the sulfonate produced by this oxidation reaction needs to be cooled to room temperature. Then, under ice-water bath conditions, sodium bisulfite is slowly and batch-wise added to remove the oxidizing substances from the sulfonate. Finally, the oxidizing property of the sulfonate solution is determined using starch-potassium iodide test paper. After confirming that the sulfonate solution has no oxidizing property, an appropriate amount of sodium bicarbonate is added to adjust the pH of the sulfonate solution to 6 to 7. The solution is then filtered to remove the solid, and the mixture is allowed to stand and separate to obtain an organic layer. The organic layer is then evaporated to dryness to obtain the crude sulfonate product. The crude sulfonate was then dissolved in methanol and stirred for 1 hour. After filtration, a filtrate was obtained. The filtrate was then evaporated to dryness to obtain a secondary crude sulfonate. Isopropanol and methyl tert-butyl ether were added to the secondary crude sulfonate for pulping to obtain a primary slurry. The slurry was then filtered to obtain a tertiary crude sulfonate. Methyl tert-butyl ether was added to the tertiary crude sulfonate for pulping twice more to obtain a secondary slurry. The secondary slurry was then filtered to obtain the sulfonate product.

[0026] It should be noted that the methyl tert-butyl ether used in this pulping process can be replaced with either diethyl ether or isopropyl ether.

[0027] It should be noted that the oxidant used is hydrogen peroxide with a mass concentration of 30%.

[0028] It should be noted that in this ion exchange process, the sulfonate and (4-tert-butylphenyl)diphenyl sulfonium chloride are first stirred in pure water for a period of time, and then dichloromethane is added and stirred overnight to obtain a product solution. The product solution is allowed to stand and separated to obtain an organic phase; the organic phase is washed with pure water and then concentrated to obtain a viscous, oily adamantane-based sulfonium salt product; ethyl acetate is then added to the adamantane-based sulfonium salt product, and the mixture is pulped at a low temperature of -10℃ to 0℃ to obtain a slurry; the slurry is filtered to obtain an adamantane-based sulfonium salt photoacid-producing agent.

[0029] It should be noted that this application provides a method for preparing adamantane-based sulfonium salt photoacid-generating agents. This method systematically improves the yield of adamantane-based sulfonium salt photoacid-generating agents by optimizing the selectivity and conversion rate of each step. The specific mechanism is as follows: 1. Catalytic and protective mechanisms of esterification reactions: (1) Methanesulfonic acid catalysis: In the esterification reflux reaction, methanesulfonic acid, as a strong protic acid, activates the carboxyl group of difluorobromoacetic acid, promotes its dehydration esterification with 1-adamantane methanol, and at the same time inhibits the elimination side reaction of the adamantane skeleton.

[0030] Steric hindrance utilization: The rigid structure of the adamantyl group reduces the probability of intramolecular cyclization in intermediate molecules, ensuring the highly selective generation of bromodifluoroacetate, thereby improving the yield of subsequent adamantane-based sulfonium salt photoacid generators.

[0031] 2. Free radical mechanism of sulfonation dehalogenation: Single electron transfer (SET): Sodium dithionite (Na2S2O4) produces SO2 under weakly alkaline conditions (adjusted by NaHCO3). ⁻ Free radicals reduce C-Br bonds via electron transfer to generate carbon radical intermediates, which then react with SO2. ⁻ Free radicals combine to form sulfite ions (R-SO2). ⁻ ).

[0032] pH control: NaHCO3 maintains the acidity or alkalinity of the reaction process, avoiding the hydrolysis of ester bonds caused by strong alkalinity, and at the same time avoiding the protonation and deactivation of sulfinate under acidic conditions.

[0033] 3. Directed transformation mechanism of oxidation reaction: Selective oxidation of sulfite: Using relatively mild oxidants such as H2O2, the sulfur atom of the sulfite group is nucleophilically attacked to form a peroxide intermediate, which is eventually hydrolyzed to a stable sulfonate (R-SO3). ⁻ This helps prevent the adamantane skeleton from oxidizing and cracking.

[0034] Segmented temperature control: Low temperature initiates the oxidation reaction process, reduces peroxidation byproducts, and increases the yield of the oxygen reaction process.

[0035] 4. Phase transfer mechanism of ion exchange: Solvent synergistic effect: Using mixed solvents (such as a mixture of dichloromethane and water) enhances the solubility of sulfonates and sulfonates, and drives the equilibrium toward the product through the exchange of interfacial ion pairs.

[0036] In summary, the present application provides a method for preparing adamantane-based sulfonium salt photoacid-generating agents. This method only requires esterification reflux reaction, sulfinization dehalogenation reaction, oxidation reaction, and ion exchange, which can comprehensively improve the yield of adamantane-based sulfonium salt photoacid-generating agents.

[0037] In some optional embodiments, the amount of 1-adamantane carboxylic acid n1, the amount of difluorobromoacetic acid n2, and the amount of methanesulfonic acid n3 satisfy: n1:n2:n3=1:(1.0 to 1.5):(0.05 to 0.1).

[0038] In these embodiments, 1-adamantane carboxylic acid, difluorobromoacetic acid and methanesulfonic acid in a molar ratio of 1:(1.0 to 1.5):(0.05 to 0.1) can undergo sufficient esterification reflux reaction to form a bromodifluoroacetic acid ester product containing adamantane under the action of methanesulfonic acid.

[0039] The amount of substance n2 of the difluorobromoacetic acid can be 1.0, 1.1, 1.2, 1.3, 1.4 or 1.5.

[0040] The amount of methanesulfonic acid, n3, can be 0.05, 0.06, 0.07, 0.08, 0.09, or 0.10.

[0041] In some alternative embodiments, the amount of sodium dithionite n4, the amount of sodium bicarbonate n5, and the amount of bromodifluoroacetate product n6 satisfy: n4:n5:n6 = (1.0 to 1.5):(1.0 to 1.2):1.0.

[0042] In these embodiments, the sodium dithionite, sodium bicarbonate, and bromodifluoroacetate products in a molar ratio of (1.0 to 1.5):(1.0 to 1.2):1.0 can undergo sufficient sulfinization and dehalogenation reaction to form sulfinates, while avoiding excessive alkalinity that could lead to ester bond hydrolysis and loss of bromodifluoroacetate products.

[0043] The amount of sodium dithionite, n4, can be 1.0, 1.1, 1.2, 1.3, 1.4, or 1.5.

[0044] The amount of sodium bicarbonate, n5, can be 1.00, 1.05, 1.10, 1.15, or 1.20.

[0045] In some alternative embodiments, the mass m1 of the oxidant and the mass m2 of the bromodifluoroacetate product satisfy the following ratio: m1:m2 = (0.6 to 0.8):1.0.

[0046] In these embodiments, an oxidant and a bromodifluoroacetate product in a mass ratio of (0.6 to 0.8):1.0 can provide sufficient oxidant in the sulfinate. The sufficient oxidant attacks the sulfur atom of the sulfinate through nucleophilic attack and forms a peroxy intermediate, which is eventually hydrolyzed into a stable sulfonate.

[0047] The mass m1 of the oxidant can be 0.6, 0.65, 0.7, 0.75 or 0.80.

[0048] In some alternative embodiments, the amount of the sulfonate n7 and the amount of the (4-tert-butylphenyl)diphenylsulfonium chloride n8 satisfy: n7:n8 = (1.0 to 2.0):1.0.

[0049] In these embodiments, sufficient ion exchange can occur between the sulfonate and (4-tert-butylphenyl)diphenyl sulfonium chloride in a molar ratio of (1.0 to 2.0):1.0 to form a pure and high-yield adamantane sulfonium salt photoacid generator.

[0050] The amount of substance n7 of the sulfonate can be 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 or 2.0.

[0051] In some optional embodiments, the esterification reflux reaction is carried out at a temperature of 75°C to 85°C for a duration of 2 hours to 4 hours; and / or The sulfonation dehalogenation reaction is carried out at a temperature of 55°C to 65°C for a duration of 2 hours to 4 hours; and / or The oxidation reaction is carried out at a temperature of 45°C to 55°C for a duration of 2 hours to 4 hours; and / or The ion exchange time is 2 to 4 hours.

[0052] In these embodiments, an esterification reflux reaction at 75°C to 85°C for 2 to 4 hours allows for sufficient reaction between 1-adamantanecarboxylic acid, difluorobromoacetic acid, and methanesulfonic acid to form a bromodifluoroacetic acid ester product containing adamantane under the action of methanesulfonic acid. Additionally, a sulfinization dehalogenation reaction at 55°C to 65°C for 2 to 4 hours allows for sufficient reaction between sodium dithionite, sodium bicarbonate, and the bromodifluoroacetic acid ester product to yield a sulfinate product. Furthermore, an oxidation reaction at 45°C to 55°C for 2 to 4 hours allows for sufficient oxidization of the sulfinate with an oxidizing agent to yield a sulfonate product. Moreover, an ion exchange reaction for 2 to 4 hours allows for sufficient ion exchange between the sulfonate and (4-tert-butylphenyl)diphenylsulfonium chloride to generate adamantane-based sulfonium salt photoacid generator with high purity and yield.

[0053] The temperature for the esterification reflux reaction can be 75℃, 76℃, 77℃, 78℃, 79℃, 80℃, 81℃, 82℃, 83℃, 84℃ or 85℃.

[0054] The esterification reflux reaction time can be 2h, 2.5h, 3.0h, 3.5h or 4.0h.

[0055] The temperature for the sulfonation dehalogenation reaction can be 55℃, 56℃, 57℃, 58℃, 59℃, 60℃, 61℃, 62℃, 63℃, 64℃ or 65℃.

[0056] The time for the sulfonation dehalogenation reaction can be 2h, 2.5h, 3.0h, 3.5h or 4.0h.

[0057] The temperature for this oxidation reaction can be 45℃, 46℃, 47℃, 48℃, 49℃, 50℃, 51℃, 52℃, 53℃, 54℃, or 55℃.

[0058] The oxidation reaction can take 2 hours, 2.5 hours, 3.0 hours, 3.5 hours, or 4.0 hours.

[0059] The ion exchange time can be 2h, 2.5h, 3.0h, 3.5h or 4.0h.

[0060] In some alternative embodiments, the bromodifluoroacetate product has the molecular structure shown in Formula 1: , Formula 1; and / or, The sulfinate has the molecular structural formula shown in Formula 2: , Equation 2; and / or, The sulfonate has the molecular structure shown in Formula 3: , Equation 3; and / or, The adamantane-based sulfonium salt photoacid-generating agent has the molecular structure shown in Formula 4: , Formula 4.

[0061] In these embodiments, the bromodifluoroacetate product is clearly identified as having the structure shown in Formula 1, indicating that the esterification reflux reaction generates the bromodifluoroacetate product containing adamantane: (3r,5r,7r-adamantane-1-yl)methyl 2-bromo-2,2-difluoroacetate. Simultaneously, a sulfinate with the molecular structure shown in Formula 2 is identified, indicating that the sulfinization dehalogenation reaction can yield the target sulfinate: (3r,5r,7r-adamantane-1-yl)methyl 2-sulfinate sodium-2,2-difluoroacetate. Furthermore, a sulfonate with the molecular structure shown in Formula 3 is identified, indicating that the oxidation reaction can yield the target sulfonate product: (3r,5r,7r-adamantane-1-yl)methyl 2-sulfinate sodium-2,2-difluoroacetate. Furthermore, it was determined that the final adamantane-based sulfonium salt photoacid-generating agent has the molecular structure shown in Formula 4, indicating that the preparation method successfully prepared 2-(3R,5R,7R-adamantane-1-yl)methoxy-1,1-difluoro-2-oxoethane-1-sulfonate (4-tert-butyl-phenyl)diphenylsulfonium salt.

[0062] In some alternative embodiments, the sulfonation dehalogenation reaction is carried out in a mixed solution of acetonitrile and ultrapure water, wherein the volume V1 of the acetonitrile and the volume V2 of the ultrapure water satisfy: V1:V2 = (1.0 to 1.2):1.0; and / or The organic solvent includes any one of the following: dichloromethane, dichloroethane, chloroform, and acetonitrile; and / or The volume V3 of the dichloromethane and the volume V4 of the water satisfy the following: V3:V4 = (1.0 to 3.0):1.0.

[0063] In these embodiments, acetonitrile and ultrapure water in a volume ratio of (1.0 to 1.2):1.0 can effectively dissolve sodium dithionite, sodium bicarbonate, and bromodifluoroacetate products, facilitating the smooth progress of the sulfinization dehalogenation reaction and ultimately yielding high-purity and high-yield sulfinates. Additionally, using an organic solvent including dichloromethane, dichloroethane, chloroform, and acetonitrile can effectively dissolve 1-adamantane-methanol, difluorobromoacetic acid, and methanesulfonic acid, promoting a thorough esterification reflux reaction to obtain a high-yield bromodifluoroacetate product containing adamantane. Furthermore, a volume ratio of dichloromethane and water in a volume ratio of (1.0 to 3.0):1.0 can form a highly soluble mixture, which is beneficial for the dissolution of sulfonates and (4-tert-butylphenyl)diphenylsulfonium chloride, promoting ion-pair exchange and thus forming high-purity and high-yield adamantane-based sulfonium salt photoacid-generating agents.

[0064] The volume V1 of the acetonitrile can be 1.00, 1.05, 1.10, 1.15 or 1.20.

[0065] The volume V3 of the dichloromethane can be 1.0, 1.5, 2.0, 2.5 or 3.0.

[0066] Based on a general inventive concept, embodiments of this application provide an adamantane-based sulfonium salt photoacid generator, which is prepared by the aforementioned preparation method.

[0067] The adamantane-based sulfonium salt photoacid generator is obtained based on the above preparation method. The specific composition of the preparation method can be referred to the above embodiments. Since the adamantane-based sulfonium salt photoacid generator adopts some or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here.

[0068] Based on a general inventive concept, embodiments of this application provide a photoresist comprising the adamantane-based sulfonium salt photoacid generator.

[0069] The photoresist is based on the above-mentioned adamantane-based sulfonium salt photoacid generator. The specific composition of the adamantane-based sulfonium salt photoacid generator can be referred to the above embodiments. Since the photoresist adopts some or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here.

[0070] The present application is further illustrated below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national / industry standards; if there is no corresponding national / industry standard, they are performed according to general international standards, conventional conditions, or conditions recommended by the manufacturer. Example

[0071] like Figure 1 As shown, a method for preparing an adamantane-based sulfonium salt photoacid-generating agent includes: S1. In an organic solvent, 1-adamantane-methanol, difluorobromoacetic acid, and methanesulfonic acid are subjected to an esterification reflux reaction to obtain a bromodifluoroacetic acid ester product containing adamantane; the specific steps are as follows: 1-Adamantane-methanol (12.0 mmol, 20 g, 1.0 eq.), difluorobromoacetic acid (14.4 mmol, 25 g, 1.2 eq.), methanesulfonic acid (0.72 mmol, 0.69 g, 0.06 eq.), and 80 mL of dichloroethane (DCE) were added to a 400 mL reaction flask. The heating mantle was set to 80 °C, and the esterification reaction was carried out under reflux for 2 h to obtain the esterification product. GC analysis of the esterification product confirmed that the 1-adamantane-methanol had reacted completely. After cooling the esterification product to room temperature, 108.8 g of 5% sodium bicarbonate solution was added and stirred for 30 min to obtain an esterification mixture. The esterification mixture was extracted and separated. 80 mL of deionized water was added to the organic layer obtained by separation and stirred for 30 min. The mixture was then extracted and separated to obtain an esterified organic phase. The esterified organic phase was dried to obtain 44 g of a yellow, viscous, oily product containing adamantane, bromodifluoroacetate.

[0072] S2. The product containing adamantane, a brominated difluoroacetate, is subjected to a sulfinization and dehalogenation reaction using sodium dithionite and sodium bicarbonate to obtain adamantane-containing sulfinate; the specific steps are as follows: The bromodifluoroacetate product containing adamantane was dissolved in 100 mL of acetonitrile, and then 90 mL of ultrapure water was added to obtain a bromodifluoroacetate product solution. 29 g of sodium dithionite (sodium hydrosulfite) and 12 g of sodium bicarbonate were added to the bromodifluoroacetate product solution to obtain a sulfinized dehalogenated mixture. The sulfinized dehalogenated mixture was heated to 60 °C using an electric heating mantle to carry out the sulfinization dehalogenation reaction for 2 h, and then allowed to stand for 15 min to separate the organic phase, which was the adamantane-containing sulfinate.

[0073] S3. Oxidize the adamantane-containing sulfinate using an oxidizing agent to obtain the adamantane-containing sulfonate; the specific steps are as follows: The adamantane-containing sulfinate was dissolved in 100 mL of ultrapure water (maintaining a volume ratio of ultrapure water to acetonitrile of 1:1) to obtain the sulfinate solvent. 27 g of 30% hydrogen peroxide was slowly added dropwise to the sulfinate solvent under ice bath conditions to avoid significant heat generation affecting the oxidation process. The oxidation reaction was carried out with stirring at 50 °C for 2 h, and then cooled to room temperature to obtain the oxidation product. The oxidation product was placed in an ice bath, and sodium bisulfite (6.56 mmol, 6.88 g) was slowly added in batches, with the addition temperature controlled at 40 °C. When the temperature of the oxidation product no longer changed significantly after the addition of sodium bisulfite, the oxidizing power of the oxidation product was determined using starch-potassium iodide test paper. After the test result showed no oxidizing power, an appropriate amount of sodium bicarbonate (0.129 mol, 10.8 g) was added to adjust the pH of the sulfonate solution to 6 to 7. The solution was filtered to remove the solid, and then allowed to stand for separation to obtain the organic layer. The organic layer was evaporated to dryness to obtain the crude sulfonate product. The crude sulfonate was then dissolved in 120 mL of methanol and stirred for 1 h. After filtration, the filtrate was obtained. The filtrate was then evaporated to dryness to obtain 40 g of secondary crude sulfonate. Isopropanol and methyl tert-butyl ether were added to the secondary crude sulfonate and pulped for 2 h until a solid product precipitated, resulting in a primary slurry. The slurry was then filtered to obtain a tertiary crude sulfonate. Methyl tert-butyl ether was added to the tertiary crude sulfonate and pulped for 2 h twice more to obtain a secondary slurry. The secondary slurry was then filtered and dried to obtain 14 g of sulfonate product: sodium 2-(3R,5R,7R-adamantane-1-yl)methoxy-1,1-difluoro-2-oxoethane-1-sulfonate (yield 34%).

[0074] S4. In a mixed system of dichloromethane and water, an adamantane-containing sulfonate salt and a (4-tert-butylphenyl)diphenyl sulfonate chloride are subjected to ion exchange to obtain an adamantane-based sulfonium salt photoacid-generating agent; the specific steps are as follows: A sulfonate containing adamantane (28.9 mmol, 10.0 g, 1 eq.) was dissolved in 100 mL of ultrapure water to obtain a mixed system. Then, (4-tert-butyl-phenyl)diphenyl sulfonium chloride (28.9 mmol, 10.2 g, 1 eq.) was added to the mixed system and stirred at room temperature for 2 h. Then, 300 mL of dichloromethane was added and stirred overnight to obtain a product solution. The product solution was allowed to stand and separated to obtain an organic phase. The organic phase was washed three times with pure water and then concentrated to obtain a viscous, oily adamantane-based sulfonium salt product. Ethyl acetate was added to the adamantane-based sulfonium salt product, and the mixture was pulped at a low temperature of -10 °C to 0 °C to obtain a slurry. The slurry was filtered to obtain 16 g of adamantane-based sulfonium salt photoacid-generating agent (yield 86%). Example

[0075] A method for preparing an adamantane-based sulfonium salt photoacid-generating agent, comprising: S1. In an organic solvent, 1-adamantane-methanol, difluorobromoacetic acid, and methanesulfonic acid are subjected to an esterification reflux reaction to obtain a bromodifluoroacetic acid ester product containing adamantane; the specific steps are as follows: 0.601 mol (100.0 g, 1.0 eq.), 0.722 mol (126.3 g, 1.2 eq.), and 36.1 mmol (3.45 g, 0.06 eq.) of methanesulfonic acid and 400 mL of dichloroethane (DCE) were added to a 1000 mL reaction flask. The heating mantle temperature was set to 80 °C, and the esterification reaction was carried out under reflux for 2 h to obtain the esterification product. GC analysis of the esterification product confirmed that the 1-adamantane methanol reaction was complete. After cooling the esterification product to room temperature, 540g of a 5% sodium bicarbonate solution was added and stirred for 30min to obtain an esterification mixture. The esterification mixture was extracted and separated. 500mL of deionized water was added to the organic layer obtained by separation and stirred for 30min. The mixture was then extracted and separated to obtain an esterified organic phase. The esterified organic phase was dried by rotary evaporation to obtain 215g of a yellow, viscous, oily product containing adamantane, bromodifluoroacetate.

[0076] S2. The product containing adamantane, a brominated difluoroacetate, is subjected to a sulfinization and dehalogenation reaction using sodium dithionite and sodium bicarbonate to obtain adamantane-containing sulfinate; the specific steps are as follows: The bromodifluoroacetate product containing adamantane was dissolved in 500 mL of acetonitrile, and then 450 mL of ultrapure water was added to obtain a bromodifluoroacetate product solution. 146 g of sodium dithionite (sodium hydrosulfite) and 60 g of sodium bicarbonate were added to the bromodifluoroacetate product solution to obtain a sulfinized dehalogenated mixture. The sulfinized dehalogenated mixture was heated to 60 °C using an electric heating mantle to carry out the sulfinization dehalogenation reaction for 2 h, and then allowed to stand for 15 min to separate the layers. The organic phase was then separated, which was the sulfinate containing adamantane.

[0077] S3. Oxidize the adamantane-containing sulfinate using an oxidizing agent to obtain the adamantane-containing sulfonate; the specific steps are as follows: The adamantane-containing sulfinate was dissolved in 500 mL of ultrapure water (maintaining a volume ratio of ultrapure water to acetonitrile of 1:1) to obtain the sulfinate solvent. 135 g of 30% hydrogen peroxide was slowly added dropwise to the sulfinate solvent under ice bath conditions to avoid significant heat generation affecting the oxidation process. The oxidation reaction was carried out with stirring at 50 °C for 2 h, and then cooled to room temperature to obtain the oxidation product. The oxidation product was placed in an ice bath, and sodium bisulfite (0.331 mol, 34.4 g) was slowly added in batches, with the addition temperature controlled at 40 °C. When the temperature of the oxidation product no longer changed significantly after the addition of sodium bisulfite, the oxidizing power of the oxidation product was determined using starch-potassium iodide test paper. After the test result showed no oxidizing power, an appropriate amount of sodium bicarbonate (0.643 mol, 54.0 g) was added to adjust the pH of the sulfonate solution to 6 to 7. The solution was filtered to remove the solid, and then allowed to stand for separation to obtain the organic layer. The organic layer was evaporated to dryness to obtain the crude sulfonate product. The crude sulfonate was then dissolved in 120 mL of methanol and stirred for 1 h. After filtration, the filtrate was obtained. The filtrate was then evaporated to dryness to obtain 200 g of secondary crude sulfonate. Isopropanol and methyl tert-butyl ether were added to the secondary crude sulfonate and pulped for 2 h until a solid product precipitated, resulting in a primary slurry. The slurry was then filtered to obtain a tertiary crude sulfonate. Methyl tert-butyl ether was added to the tertiary crude sulfonate and pulped for 2 h twice more to obtain a secondary slurry. The secondary slurry was then filtered and dried to obtain 72 g of sulfonate product: sodium 2-(3R,5R,7R-adamantane-1-yl)methoxy-1,1-difluoro-2-oxoethane-1-sulfonate (yield 35%).

[0078] S4. In a mixed system of dichloromethane and water, an adamantane-containing sulfonate salt and a (4-tert-butylphenyl)diphenyl sulfonate chloride are subjected to ion exchange to obtain an adamantane-based sulfonium salt photoacid-generating agent; the specific steps are as follows: A sulfonate containing adamantane (0.208 mol, 72 g, 1 eq.) was dissolved in 720 mL of ultrapure water to obtain a mixed system. Then, (4-tert-butyl-phenyl)diphenyl sulfonium chloride (0.208 mol, 74 g, 1 eq.) was added to the mixed system and stirred at room temperature for 2 h. Then, 2160 mL of dichloromethane was added and stirred overnight to obtain a product solution. The product solution was allowed to stand and separated to obtain an organic phase. The organic phase was washed three times with pure water and then concentrated to obtain a viscous, oily adamantane-based sulfonium salt product. Ethyl acetate was added to the adamantane-based sulfonium salt product, and the mixture was pulped at a low temperature of -10 °C to 0 °C to obtain a slurry. The slurry was filtered to obtain 116 g of adamantane-based sulfonium salt photoacid-generating agent (yield 89%). Example

[0079] A method for preparing an adamantane-based sulfonium salt photoacid-generating agent, comprising: S1. In an organic solvent, 1-adamantane-methanol, difluorobromoacetic acid, and methanesulfonic acid are subjected to an esterification reflux reaction to obtain a bromodifluoroacetic acid ester product containing adamantane; the specific steps are as follows: 1-Adamantane-methanol (1.50 mol, 250 g, 1.0 eq.), difluorobromoacetic acid (1.80 mol, 315 g, 1.2 eq.), methanesulfonic acid (90.0 mmol, 8.671 g, 0.06 eq.), and 1.09 L of dichloroethane (DCE) were added to a 5 L reaction flask. The heating mantle was set to 80 °C, and the esterification reaction was carried out under reflux for 2 h to obtain the esterification product. GC analysis of the esterification product confirmed that the 1-adamantane-methanol had reacted completely. After cooling the esterification product to room temperature, 1360g of a 5% sodium bicarbonate solution was added and stirred for 30min to obtain an esterification mixture. The esterification mixture was extracted and separated. 1000mL of deionized water was added to the organic layer obtained by separation and stirred for 30min. The mixture was then extracted and separated to obtain an esterified organic phase. The esterified organic phase was dried to obtain 546g of a yellow, viscous, oily product containing adamantane, bromodifluoroacetate.

[0080] S2. The product containing adamantane, a brominated difluoroacetate, is subjected to a sulfinization and dehalogenation reaction using sodium dithionite and sodium bicarbonate to obtain adamantane-containing sulfinate; the specific steps are as follows: The bromodifluoroacetate product containing adamantane was dissolved in 1.22 L of acetonitrile, and then 1.1 L of ultrapure water was added to obtain a bromodifluoroacetate product solution. 360 g of sodium dithionite (sodium hydrosulfite) and 150 g of sodium bicarbonate were added to the bromodifluoroacetate product solution to obtain a sulfinized dehalogenated mixture. The sulfinized dehalogenated mixture was heated to 60 °C using an electric heating mantle to carry out the sulfinization dehalogenation reaction for 2 h, and then allowed to stand for 15 min to separate the layers. The organic phase was then separated, which was the sulfinate containing adamantane.

[0081] S3. Oxidize the adamantane-containing sulfinate using an oxidizing agent to obtain the adamantane-containing sulfonate; the specific steps are as follows: The adamantane-containing sulfinate was dissolved in 1.1 L of ultrapure water (maintaining a volume ratio of ultrapure water to acetonitrile of 1:1) to obtain the sulfinate solvent. 342 g of 30% hydrogen peroxide was slowly added dropwise to the sulfinate solvent under ice bath conditions to avoid significant heat generation affecting the oxidation process. The oxidation reaction was carried out with stirring at 50 °C for 2 h, and then cooled to room temperature to obtain the oxidation product. The oxidation product was placed in an ice bath, and sodium bisulfite (0.82 mol, 86 g) was slowly added in batches, with the addition temperature controlled at 40 °C. When the temperature of the oxidation product no longer changed significantly after the addition of sodium bisulfite, the oxidizing power of the oxidation product was determined using starch-potassium iodide test paper. After the test result showed no oxidizing power, an appropriate amount of sodium bicarbonate (1.61 mol, 135 g) was added to adjust the pH of the sulfonate solution to 6 to 7. The solution was filtered to remove the solid, and then allowed to stand for separation to obtain the organic layer. The organic layer was evaporated to dryness to obtain the crude sulfonate product. The crude sulfonate was then dissolved in 1.5 L of methanol and stirred for 1 h. After filtration, the filtrate was obtained. The filtrate was then evaporated to dryness to obtain 495 g of secondary crude sulfonate. Isopropanol and methyl tert-butyl ether were added to the secondary crude sulfonate and pulped for 2 h until a solid product precipitated, resulting in a primary slurry. The slurry was then filtered to obtain a tertiary crude sulfonate. 900 mL of methyl tert-butyl ether was added to the tertiary crude slurry and pulped for 2 h twice more to obtain a secondary slurry. The secondary slurry was filtered and dried to obtain 179 g of sulfonate product: sodium 2-(3R,5R,7R-adamantane-1-yl)methoxy-1,1-difluoro-2-oxoethane-1-sulfonate (yield 34%).

[0082] S4. In a mixed system of dichloromethane and water, an adamantane-containing sulfonate salt and a (4-tert-butylphenyl)diphenyl sulfonate chloride are subjected to ion exchange to obtain an adamantane-based sulfonium salt photoacid-generating agent; the specific steps are as follows: A sulfonate containing adamantane (0.289 mol, 100.0 g, 1 eq.) was dissolved in 1 L of ultrapure water to obtain a mixed system. Then, (4-tert-butyl-phenyl)diphenyl sulfonium chloride (0.289 mol, 102.0 g, 1 eq.) was added to the mixed system and stirred at room temperature for 2 h. Then, 1 L of dichloromethane was added and stirred overnight to obtain a product solution. The product solution was allowed to stand and separated to obtain an organic phase. The organic phase was washed three times with pure water and then concentrated to obtain a viscous, oily adamantane-based sulfonium salt product. Ethyl acetate was added to the adamantane-based sulfonium salt product, and the mixture was pulped at a low temperature of -10°C to 0°C to obtain a slurry. The slurry was filtered to obtain 160 g of adamantane-based sulfonium salt photoacid-generating agent (yield 86%). Example

[0083] A method for preparing an adamantane-based sulfonium salt photoacid-generating agent, comprising: S1. In an organic solvent, 1-adamantane-methanol, difluorobromoacetic acid, and methanesulfonic acid are subjected to an esterification reflux reaction to obtain a bromodifluoroacetic acid ester product containing adamantane; the specific steps are as follows: 1-Adamantane-methanol (3.01 mol, 500.0 g, 1.0 eq.), difluorobromoacetic acid (3.61 mol, 631.5 g, 1.2 eq.), methanesulfonic acid (0.181 mmol, 17.3 g, 0.06 eq.), and 2 L of dichloroethane (DCE) were added to a 5 L reaction flask. The heating mantle temperature was set to 80 °C, and the esterification reaction was carried out under reflux for 2 h to obtain the esterification product. GC analysis of the esterification product confirmed that the 1-adamantane-methanol had reacted completely. After cooling the esterification product to room temperature, 2.5 kg of 5% sodium bicarbonate solution was added and stirred for 30 min to obtain an esterification mixture. The esterification mixture was extracted and separated. 2.5 L of deionized water was added to the organic layer obtained by separation and stirred for 30 min. The mixture was then extracted and separated to obtain an esterified organic phase. The esterified organic phase was dried by rotary evaporation to obtain 1065 g of a yellow, viscous, oily product containing adamantane, bromodifluoroacetate.

[0084] S2. The product containing adamantane, a brominated difluoroacetate, is subjected to a sulfinization and dehalogenation reaction using sodium dithionite and sodium bicarbonate to obtain adamantane-containing sulfinate; the specific steps are as follows: The bromodifluoroacetate product containing adamantane was dissolved in 2.5 L of acetonitrile, and then 2.25 L of ultrapure water was added to obtain a bromodifluoroacetate product solution. 750 g of sodium dithionite (sodium hydrosulfite) and 300 g of sodium bicarbonate were added to the bromodifluoroacetate product solution to obtain a sulfinized dehalogenated mixture. The sulfinized dehalogenated mixture was heated to 60 °C using an electric heating mantle to carry out the sulfinization dehalogenation reaction for 2 h, and then allowed to stand for 15 min to separate the layers. The organic phase was then separated, which was the sulfinate containing adamantane.

[0085] S3. Oxidize the adamantane-containing sulfinate using an oxidizing agent to obtain the adamantane-containing sulfonate; the specific steps are as follows: The adamantane-containing sulfinate was dissolved in 2.5 L of ultrapure water (maintaining a volume ratio of ultrapure water to acetonitrile of 1:1) to obtain the sulfinate solvent. 673 g of 30% hydrogen peroxide was slowly added dropwise to the sulfinate solvent under ice bath conditions to avoid significant heat generation affecting the oxidation process. The oxidation reaction was carried out with stirring at 50 °C for 2 h, and then cooled to room temperature to obtain the oxidation product. The oxidation product was placed in an ice bath, and sodium bisulfite (1.68 mol, 175 g) was slowly added in batches, with the addition temperature controlled at 40 °C. When the temperature of the oxidation product no longer changed significantly after the addition of sodium bisulfite, the oxidizing power of the oxidation product was determined using starch-potassium iodide test paper. After the test result showed no oxidizing power, an appropriate amount of sodium bicarbonate (3.21 mol, 270 g) was added to adjust the pH of the sulfonate solution to 6 to 7. The solution was filtered to remove the solid, and then allowed to stand for separation to obtain the organic layer. The organic layer was evaporated to dryness to obtain the crude sulfonate product. The crude sulfonate was then dissolved in methanol and stirred for 1 hour. After filtration, the filtrate was obtained. The filtrate was then evaporated to dryness to obtain 1015 g of secondary crude sulfonate. Isopropanol and methyl tert-butyl ether were added to the secondary crude sulfonate and pulped for 2 hours until a solid product precipitated, resulting in a primary slurry. The slurry was then filtered to obtain a tertiary crude sulfonate. Methyl tert-butyl ether was added to the tertiary crude sulfonate and pulped for 2 hours twice more to obtain a secondary slurry. The secondary slurry was then filtered and dried to obtain 375 g of sulfonate product: sodium 2-(3R,5R,7R-adamantane-1-yl)methoxy-1,1-difluoro-2-oxoethane-1-sulfonate (yield 36%).

[0086] S4. In a mixed system of dichloromethane and water, an adamantane-containing sulfonate salt and a (4-tert-butylphenyl)diphenyl sulfonate chloride are subjected to ion exchange to obtain an adamantane-based sulfonium salt photoacid-generating agent; the specific steps are as follows: A sulfonate containing adamantane (1.08 mol, 375 g, 1 eq.) was dissolved in 100 mL of ultrapure water to obtain a mixed system. Then, (4-tert-butyl-phenyl)diphenyl sulfonium chloride (28.9 mmol, 383 g, 1 eq.) was added to the mixed system and stirred at room temperature for 2 h. Then, 3.75 L of dichloromethane was added and stirred overnight to obtain a product solution. The product solution was allowed to stand and separated to obtain an organic phase. The organic phase was washed three times with pure water and then concentrated to obtain a viscous, oily adamantane-based sulfonium salt product. Ethyl acetate was added to the adamantane-based sulfonium salt product, and the mixture was pulped at a low temperature of -10 °C to 0 °C to obtain a slurry. The slurry was filtered to obtain 605 g of adamantane-based sulfonium salt photoacid-generating agent (yield 87%). Example

[0087] A method for preparing an adamantane-based sulfonium salt photoacid-generating agent, comprising: S1. In an organic solvent, 1-adamantane-methanol, difluorobromoacetic acid, and methanesulfonic acid are subjected to an esterification reflux reaction to obtain a bromodifluoroacetic acid ester product containing adamantane; the specific steps are as follows: 6.02 mol (1000.0 g, 1.0 eq.), difluorobromoacetic acid (7.22 mol, 1263.0 g, 1.2 eq.), methanesulfonic acid (0.361 mol, 34.6 g, 0.06 eq.), and 4 L of dichloroethane (DCE) were added to a reaction flask. The heating mantle was set to 80 °C, and the esterification reaction was carried out under reflux for 2 h to obtain the esterification product. GC analysis of the esterification product confirmed that the 1-adamantane methanol reaction was complete. After cooling the esterification product to room temperature, 5 kg of 5% sodium bicarbonate solution was added and stirred for 30 min to obtain an esterification mixture. The esterification mixture was extracted and separated. 5 L of deionized water was added to the separated organic layer and stirred for 30 min. The mixture was then extracted and separated to obtain an esterified organic phase. The esterified organic phase was dried by rotary evaporation to obtain 2150 g of a yellow, viscous, oily product containing adamantane, bromodifluoroacetate.

[0088] S2. The product containing adamantane, a brominated difluoroacetate, is subjected to a sulfinization and dehalogenation reaction using sodium dithionite and sodium bicarbonate to obtain adamantane-containing sulfinate; the specific steps are as follows: The bromodifluoroacetate product containing adamantane was dissolved in 5 L of acetonitrile, and then 4.5 mL of ultrapure water was added to obtain a bromodifluoroacetate product solution. 1500 g of sodium dithionite (sodium hydrosulfite) and 600 g of sodium bicarbonate were added to the bromodifluoroacetate product solution to obtain a sulfinized dehalogenated mixture. The sulfinized dehalogenated mixture was heated to 60 °C using an electric heating mantle to carry out the sulfinization dehalogenation reaction for 2 h, and then allowed to stand for 15 min to separate the layers. The organic phase was then separated, which was the sulfinate containing adamantane.

[0089] S3. Oxidize the adamantane-containing sulfinate using an oxidizing agent to obtain the adamantane-containing sulfonate; the specific steps are as follows: The adamantane-containing sulfinate was dissolved in 5 L of ultrapure water (maintaining a volume ratio of ultrapure water to acetonitrile of 1:1) to obtain the sulfinate solvent. 1345 g of 30% hydrogen peroxide was slowly added dropwise to the sulfinate solvent under ice bath conditions to avoid significant heat generation affecting the oxidation process. The oxidation reaction was carried out with stirring at 50 °C for 2 h, and then cooled to room temperature to obtain the oxidation product. The oxidation product was placed in an ice bath, and sodium bisulfite (3.36 mol, 350 g) was slowly added in batches, with the temperature controlled at 40 °C during the addition. When the temperature of the oxidation product no longer changed significantly after the addition of sodium bisulfite, the oxidizing power of the oxidation product was determined using starch-potassium iodide test paper. After the test result showed no oxidizing power, an appropriate amount of sodium bicarbonate (6.42 mol, 540 g) was added to adjust the pH of the sulfonate solution to 6 to 7. The solution was filtered to remove the solid, and then allowed to stand for separation to obtain the organic layer. The organic layer was evaporated to dryness to obtain the crude sulfonate product. The crude sulfonate was then dissolved in methanol and stirred for 1 hour. After filtration, the filtrate was obtained. The filtrate was then evaporated to dryness to obtain 2035 g of secondary crude sulfonate. Isopropanol and methyl tert-butyl ether were added to the secondary crude sulfonate and pulped for 2 hours until a solid product precipitated, resulting in a primary slurry. The slurry was then filtered to obtain a tertiary crude sulfonate. Methyl tert-butyl ether was added to the tertiary crude sulfonate and pulped for 2 hours twice more to obtain a secondary slurry. The secondary slurry was then filtered and dried to obtain 750 g of sulfonate product: sodium 2-(3R,5R,7R-adamantane-1-yl)methoxy-1,1-difluoro-2-oxoethane-1-sulfonate (yield 36%).

[0090] S4. In a mixed system of dichloromethane and water, an adamantane-containing sulfonate salt and a (4-tert-butylphenyl)diphenyl sulfonate chloride are subjected to ion exchange to obtain an adamantane-based sulfonium salt photoacid-generating agent; the specific steps are as follows: A sulfonate containing adamantane (2.16 mol, 750 g, 1 eq.) was dissolved in 5 L of ultrapure water to obtain a mixed system. Then, (4-tert-butyl-phenyl)diphenyl sulfonium chloride (2.16 mol, 766 g, 1 eq.) was added to the mixed system and stirred at room temperature for 2 h. Then, 5 L of dichloromethane was added and stirred overnight to obtain a product solution. The product solution was allowed to stand and separated to obtain an organic phase. The organic phase was washed three times with pure water and then concentrated to obtain a viscous, oily adamantane-based sulfonium salt product. Ethyl acetate was added to the adamantane-based sulfonium salt product, and the mixture was pulped at a low temperature of -10 °C to 0 °C to obtain a slurry. The slurry was filtered to obtain 1210 g of adamantane-based sulfonium salt photoacid-generating agent (yield 87%).

[0091] Comparative Example 1 Compared to Example 1, Comparative Example 1 differs as follows, while all other aspects remain the same: The amounts of 1-adamantane-methanol n1 and difluorobromoacetic acid n2 satisfy the following ratio: n1:n2=1:0.5.

[0092] Comparative Example 2 Compared to Example 1, Comparative Example 1 differs as follows, while all other aspects remain the same: The amounts of 1-adamantane-methanol n1 and difluorobromoacetic acid n2 satisfy the following ratio: n1:n2=1:2.0.

[0093] Comparative Example 3 Compared to Example 1, Comparative Example 1 differs as follows, while all other aspects remain the same: The amounts of sodium dithionite (n4), sodium bicarbonate (n5), and bromodifluoroacetate (n6) satisfy the following ratio: n4:n5:n6 = 2.0:0.5:1.0.

[0094] Comparative Example 4 Compared to Example 1, Comparative Example 1 differs as follows, while all other aspects remain the same: The amounts of sodium dithionite (n4), sodium bicarbonate (n5), and bromodifluoroacetate (n6) satisfy the following ratio: n4:n5:n6 = 0.5:1.5:1.0.

[0095] Comparative Example 5 Compared to Example 1, Comparative Example 1 differs as follows, while all other aspects remain the same: The mass m1 of the oxidant and the mass m2 of the bromodifluoroacetate product satisfy the following ratio: m1:m2=0.5:1.0.

[0096] Comparative Example 6 Compared to Example 1, Comparative Example 1 differs as follows, while all other aspects remain the same: The mass m1 of the oxidant and the mass m2 of the bromodifluoroacetate product satisfy the following ratio: m1:m2 = 1.2:1.0.

[0097] Comparative Example 7 Compared to Example 1, Comparative Example 1 differs as follows, while all other aspects remain the same: The amounts of sulfonate n7 and (4-tert-butylphenyl)diphenylsulfonium chloride n8 satisfy the following ratio: n7:n8 = 0.5:1.0.

[0098] Comparative Example 8 Compared to Example 1, Comparative Example 1 differs as follows, while all other aspects remain the same: The amounts of sulfonate n7 and (4-tert-butylphenyl)diphenylsulfonium chloride n8 satisfy the following ratio: n7:n8 = 4:1.0.

[0099] Relevant experimental and effect data: 1. The adamantane-based sulfonium salt photoacid-generating agents obtained in Example 1 were collected, and the detection results of the 1H NMR spectrum were as follows: 1H NMR (d-DMSO, 400 MHz) δ 7.75-7.88 (m, 14 H), 3.81 (s, 2 H), 3.33 (s, 1H), 1.91-1.92 (m, 3 H), 1.51-1.67 (m, 11 H), 1.32 (s, 9 H). 2. The yields of adamantane-based sulfonium salt photoacid-generating agents obtained in each example and comparative example were collected, and the results are shown in Table 1.

[0100]

[0101] As shown in Table 1, the preparation method of the adamantane-based sulfonium salt photoacid generator provided in this application only requires esterification reflux reaction, sulfinization dehalogenation reaction, oxidation reaction and ion exchange, which can comprehensively improve the yield of the adamantane-based sulfonium salt photoacid generator to more than 85%.

[0102] Compared to Example 1, Comparative Example 1 used too little difluorobromoacetic acid, which resulted in insufficient esterification reflux reaction and a decrease in the yield of the final sulfonium salt photoacid generator; while Comparative Example 2 used too much difluorobromoacetic acid, but its yield could only be stabilized at 85%, which would undoubtedly increase the raw material cost of the preparation method.

[0103] Compared to Example 1, Comparative Example 3 used too much sodium dithionite and too little sodium bicarbonate, which affected the pH environment of the sulfonation dehalogenation reaction, reducing the yield of sulfinates and ultimately decreasing the yield of adamantane-based sulfonium salt photoacid-generating agents. Furthermore, Comparative Example 4 used too little sodium dithionite and too much sodium bicarbonate, resulting in a slightly alkaline pH environment for the sulfonation dehalogenation reaction, and insufficient feedstock further reduced the yield of sulfinates, ultimately decreasing the yield of adamantane-based sulfonium salt photoacid-generating agents.

[0104] Compared to Example 1, Comparative Example 5 used too little oxidant, which made it difficult for the oxidation reaction of sulfite to proceed fully, reducing the yield of sulfonate and ultimately reducing the yield of adamantane-based sulfonium salt photoacid generators. Furthermore, Comparative Example 6 used too much oxidant. Although it increased the yield of sulfonate, it resulted in a significant waste of oxidant, requiring the subsequent addition of large amounts of sodium bisulfite for neutralization, thus increasing the cost of the preparation method.

[0105] Compared to Example 1, Comparative Example 7 used less sulfonate, directly affecting the yield of adamantane-based sulfonium salt photoacid generators. Furthermore, Comparative Example 8 used more sulfonate. Although this yielded a higher yield of adamantane-based sulfonium salt photoacid generators, the excessive addition of sulfonate resulted in lower purity of the final adamantane-based sulfonium salt photoacid generator, requiring a subsequent desalting step and increasing the cost of the preparation method.

[0106] In summary, the present application provides a method for preparing adamantane-based sulfonium salt photoacid-generating agents. This method can systematically improve the yield of adamantane-based sulfonium salt photoacid-generating agents by optimizing the parameters and conditions of the esterification reflux reaction, sulfination dehalogenation reaction, oxidation reaction, and ion exchange.

[0107] Furthermore, this application provides a method for preparing an adamantane-based sulfonium salt photoacid-generating agent. This method is simple, involves relatively conventional reaction conditions, and is easy to purify later. Additionally, the raw material cost is low and the final product yield is high, indicating significant potential for industrial production.

[0108] In addition, the present application provides a method for preparing an adamantane-based sulfonium salt photoacid generator. The sodium 2-(3R,5R,7R-adamantane-1-yl)methoxy-1,1-difluoro-2-oxoethane-1-sulfonate obtained by the oxidation reaction is an important intermediate for photoacid generators. This type of adamantane-based polyfluorosulfonate anion is a core material in the field of photoresist and can be widely used in semiconductor manufacturing, photoresist formulation, imaging systems and photocurable coatings.

[0109] Furthermore, this application provides an adamantane-based sulfonium salt photoacid generator. The adamantane backbone in this adamantane-based sulfonium salt photoacid generator imparts excellent chemical stability, thermal stability, and optical properties. For example, it can reduce the diffusion rate of acid in photoresist, reduce the edge roughness of patterns during the photolithography stage, and improve the resolution of patterns during the photolithography stage. Therefore, this adamantane-based sulfonium salt photoacid generator can be effectively applied in fields such as semiconductor photoresists, high-resolution imaging systems, and functional materials, and has potential industry value.

[0110] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed in this application.

Claims

1. A method for preparing an adamantane-based sulfonium salt photoacid-generating agent, the method comprising: In an organic solvent, 1-adamantane methanol, difluorobromoacetic acid and methanesulfonic acid are subjected to an esterification reflux reaction to obtain a bromodifluoroacetic acid ester product containing adamantane. The bromodifluoroacetate product containing adamantane was subjected to a sulfinization dehalogenation reaction using sodium dithionite and sodium bicarbonate to obtain adamantane-containing sulfinate. The sulfinate containing adamantane is oxidized using an oxidizing agent to obtain a sulfonate containing adamantane. In a mixture of dichloromethane and water, the sulfonate containing adamantane and the (4-tert-butylphenyl)diphenyl sulfonium chloride are subjected to ion exchange to obtain an adamantane-based sulfonium salt photoacid-generating agent.

2. The preparation method according to claim 1, characterized in that, The amounts of 1-adamantane carboxylic acid n1, difluorobromoacetic acid n2, and methanesulfonic acid n3 satisfy the following ratio: n1:n2:n3 = 1:(1.0 to 1.5):(0.05 to 0.1).

3. The preparation method according to claim 1, characterized in that, The amounts of sodium dithionite n4, sodium bicarbonate n5, and bromodifluoroacetate product n6 satisfy the following ratio: n4:n5:n6 = (1.0 to 1.5):(1.0 to 1.2):1.

0.

4. The preparation method according to claim 1, characterized in that, The mass m1 of the oxidant and the mass m2 of the bromodifluoroacetate product satisfy the following ratio: m1:m2 = (0.6 to 0.8):1.

0.

5. The preparation method according to claim 1, characterized in that, The amount of substance n7 of the sulfonate and the amount of substance n8 of the (4-tert-butylphenyl)diphenylsulfonium chloride satisfy: n7:n8 = (1.0 to 2.0):1.

0.

6. The preparation method according to claim 1, characterized in that, The esterification reflux reaction is carried out at a temperature of 75°C to 85°C for a duration of 2 hours to 4 hours; and / or The sulfonation dehalogenation reaction is carried out at a temperature of 55°C to 65°C for a duration of 2 hours to 4 hours; and / or The oxidation reaction is carried out at a temperature of 45°C to 55°C for a duration of 2 hours to 4 hours; and / or The oxidant is added at a temperature of -10°C to 10°C; and / or The ion exchange time is 2 to 4 hours.

7. The preparation method according to claim 1, characterized in that, The bromodifluoroacetate product has the molecular structure shown in Formula 1: ， Formula 1; and / or, The sulfinate has the molecular structural formula shown in Formula 2: ， Equation 2; and / or, The sulfonate has the molecular structure shown in Formula 3: ， Equation 3; and / or, The adamantane-based sulfonium salt photoacid-generating agent has the molecular structure shown in Formula 4: ， Formula 4.

8. The preparation method according to claim 1, characterized in that, The sulfonation dehalogenation reaction is carried out in a mixed solution of acetonitrile and ultrapure water, wherein the volume V1 of the acetonitrile and the volume V2 of the ultrapure water satisfy: V1:V2 = (1.0 to 1.2):1.0; and / or The organic solvent includes any one of the following: dichloromethane, dichloroethane, chloroform, and acetonitrile; and / or The volume V3 of the dichloromethane and the volume V4 of the water satisfy the following: V3:V4 = (1.0 to 3.0):1.

0.

9. An adamantane-based sulfonium salt photoacid generator, wherein the photoacid generator is prepared by the preparation method according to any one of claims 1 to 8.

10. A photoresist comprising the adamantane-based sulfonium salt photoacid generator as described in claim 9.

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