Tert-butyl-containing sulfonium salt photoacid generator and preparation method thereof

Abstract

The invention provides a tert-butyl-containing sulfonium salt photoacid generator and a preparation method thereof, and the preparation method comprises the following steps: 1, preparing a Grignard reagent: reacting 3, 5-di-tert-butyl bromobenzene with metal magnesium to generate the corresponding Grignard reagent; step 2, preparation of an intermediate sulfonium bromide: diphenylsulfoxide generates a trimethylsilyl substituted sulfonium salt intermediate under the action of a reagent a, then the trimethylsilyl substituted sulfonium salt intermediate reacts with the Grignard reagent obtained in the step 1, and the intermediate sulfonium bromide is generated after acidification and devitrification; and step 3, preparing the sulfonium salt photoacid generator containing the tertiary butyl: carrying out ion exchange reaction on the intermediate sulfonium bromide salt obtained in the step 2 and an anion reagent, and purifying to obtain the sulfonium salt photoacid generator containing the tertiary butyl. The invention provides a novel sulfonium salt PAG compound. Compared with triphenyl sulfonium salt, one benzene ring of the compound contains two tert-butyl substitutions. The solubility and compatibility in common organic solvents and resin systems are greatly improved by increasing the hydrophobicity.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of photochemical materials, and relates to a photoacid generator, in particular to a tert-butyl-containing sulfonium salt photoacid generator and a preparation method thereof. BACKGROUND

[0002] Photoetching technology refers to a micro-fabrication technology that uses photoetching materials (in particular photoresists) to transfer a pattern on a mask to a substrate through a process of exposure, development and etching, etc. under the chemical sensitivity of visible light, ultraviolet light, electron beams, etc.

[0003] Photoetching materials (in particular photoresists), also known as photoresists, are the most critical functional chemical materials involved in photoetching technology, and the main components are resin, photoacid generator, and solvent and corresponding additives. Such materials have photo (including visible light, ultraviolet light, electron beams, etc.) chemical sensitivity, and the solubility in a developing solution changes after photochemical reaction.

[0004] Photoacid generator (PAG) is the core component of chemical amplification photoresist (CAR), which generates strong acid to catalyze resin deprotection reaction after exposure, forming a dissolution contrast. Sulfonium salt PAG (such as triphenyl sulfonium salt) is widely used in ArF / EUV photoetching process due to high photosensitivity and stability. In the prior art, only the anion is optimized or small steric alkyl groups (such as methyl and ethyl) are introduced, and there is no scheme for modifying the sulfonium salt cation with a large steric group (such as tert-butyl) to improve the solubility. SUMMARY

[0005] In view of the deficiencies in the prior art, the purpose of the present application is to provide a tert-butyl-containing sulfonium salt photoacid generator and a preparation method thereof, which solves the technical problem in the prior art that the sulfonium salt cation is not modified with a large steric group to improve the solubility in the photoacid generator.

[0006] To solve the above technical problems, the present application adopts the following technical solutions: A tert-butyl-containing sulfonium salt photoacid generator, the structural formula of the tert-butyl-containing sulfonium salt photoacid generator is: ; In the formula: selected from triflate (CF3SO3-) or perfluorobutylsulfonate (C4F9SO3-).

[0007] The present application also protects a preparation method of a tert-butyl-containing sulfonium salt photoacid generator, which is performed according to the following steps: Step 1: Preparation of Grignard reagent: 3,5-di-tert-butylbromobenzene is reacted with magnesium to form the corresponding Grignard reagent; Step two, preparation of intermediate bromosulfonium salt: Diphenylsulfoxide is reacted with reagent a to form trimethylsilyl substituted sulfonium salt intermediate, which is then reacted with the Grignard reagent obtained in step one, and after acidification and crystallization, the intermediate bromosulfonium salt is obtained.

[0008] Step three, preparation of tert-butyl-containing sulfonium salt photoacid generator: The intermediate bromosulfonium salt obtained in step two is subjected to ion exchange reaction with anion reagent, and after purification, the tert-butyl-containing sulfonium salt photoacid generator is obtained.

[0009] The present application also has the following technical features: In step two, the reagent a is trimethylchlorosilane.

[0010] In step two, the acid used for acidification is hydrobromic acid.

[0011] In step two, the solvent used for crystallization is methyl tert-butyl ether.

[0012] In step three, the anion reagent is sodium triflate or sodium perfluorobutylsulfonate.

[0013] In step three, the solvent for ion exchange reaction is selected from water or dichloromethane.

[0014] Compared with the prior art, the present application has the following technical effects: (I) The present application provides a new sulfonium salt PAG compound, which has two tert-butyl groups substituted on one of the phenyl rings compared to triphenylsulfonium salt. By increasing the hydrophobicity, the solubility and compatibility in commonly used organic solvents and resin systems are greatly improved.

[0015] (II) In the present application, the introduction of tert-butyl increases the solubility of the entire molecule in non-polar or weakly polar solvents (such as propylene glycol methyl ether acetate PGMEA commonly used in photoresist or other organic monomer / oligomer systems); the bulky, non-planar tert-butyl group disrupts the symmetry and tendency of close packing of the molecule, reducing the crystallinity, making it easier to form a uniform and stable solution. These two points are crucial for the processing stability, storage life and film quality of photoresist and photocuring formulations.

[0016] (III) In the present application, the introduction of tert-butyl may also have a beneficial effect on the photo-reaction efficiency, absorption characteristics and acid diffusion behavior, ultimately improving the performance of photolithography or photocuring process (such as sensitivity, resolution, line edge roughness).

[0017] (IV) The application provides a new sulfonium salt photoacid generator, which contains two tert-butyl substituents on one of the phenyl groups, compared with traditional triphenyl sulfonium salt, by means of minimum structural modification: introducing large steric hindrance group to modify the sulfonium cation to improve the overall solubility; the synthesis scheme has research feasibility and industrialization potential, and realizes property breakthrough through precise structure regulation, and provides core material guarantee for photoresist process.

[0018] (V) The three-step synthesis route of the application is economical, raw materials are easy to obtain, and reaction conditions are mild, and has research feasibility and industrialization potential.

[0019] The specific content of the application will be further explained and described in detail in combination with the following embodiments. DETAILED DESCRIPTION

[0020] It should be noted that all materials and instruments in the application, unless otherwise specified, are known materials and instruments in the art.

[0021] The tert-butyl-containing sulfonium salt compound of the application is used as a photoacid generator.

[0022] The following gives specific embodiments of the application, it should be noted that the application is not limited to the following specific embodiments, and any equivalent transformation based on the technical scheme of the application falls within the protection scope of the application.

[0023] Example 1: This embodiment gives a preparation method of a tert-butyl-containing sulfonium salt photoacid generator, which is carried out according to the following synthesis route: ; .

[0024] The method is carried out according to the following steps: Step one, preparation of Grignard reagent: Under the protection of nitrogen flow, 2.2g of magnesium, 50ml of tetrahydrofuran and 1 iodine element were added into a reaction kettle, 13.9g of 3,5-di-tert-butyl bromobenzene was added dropwise into the tetrahydrofuran solution and heated to initiate the reaction, after the dropwise addition was completed, the reaction was refluxed for 2 hours and then cooled to room temperature to obtain the Grignard reagent.

[0025] Step two, preparation of intermediate bromosulfonium salt: In another reaction flask, dichloromethane 60.0 g and diphenyl sulfoxide (compound 1-1) 6.0 g were added under nitrogen flow protection, and the temperature was lowered to 5°C with ice water bath. Trimethylsilyl chloride 9.9 g was added dropwise. After 1 hour of reaction at below 20°C, trimethylsilyl substituted sulfonium salt intermediate was generated. Then the Grignard reagent prepared in step one was added dropwise. After completion, the reaction was carried out at below 20°C for 2.5 hours. Then water was added dropwise to quench the reaction at below 20°C. After acidification with hydrobromic acid and crystallization with methyl tert-butyl ether, the intermediate brominated sulfonium salt (compound 1-2) was obtained (yield: 68%, 9.4 g).

[0026] Step three, preparation of the tert-butyl-containing sulfonium salt photoacid generator: The intermediate brominated sulfonium salt (compound 1-2) 10.0 g obtained in step two was dissolved in dichloromethane 100 mL to obtain an organic phase. Sodium triflate 3.4 g was dissolved in ultrapure water 50 mL to obtain an aqueous phase. Then the aqueous phase was added to the organic phase, and the mixture was stirred vigorously at room temperature for 2 hours. After separation, the aqueous phase was back-extracted with dichloromethane (2×30 mL) to obtain the separated organic phase, which was combined. The separated organic phase was washed with ultrapure water (3×50 mL). After rotary evaporation, 100 mL of methyl tert-butyl ether was added for recrystallization to obtain white crystalline compound (compound 1-3) (yield: 90%, 9.4 g), which is the tert-butyl-containing sulfonium salt photoacid generator.

[0027] The structural characterization data of the white crystalline compound obtained in this example are as follows: In 300 MHz, DMSO 1 H-NMR δ (ppm): 7.45 (1H, s); 7.33-7.36 (10H, m); 7.16 (2H, s); 1.32 (18H, s).

[0028] LC-MS: Cation 375; Anion 149.

[0029] From the above structural characterization data, it can be seen that the white crystalline compound obtained in this example is the target product compound 1-3.

[0030] Example 2: This example gives a method for preparing a tert-butyl-containing sulfonium salt photoacid generator, which is carried out according to the following synthetic route: ; .

[0031] The method is carried out according to the following steps: Step one, preparation of Grignard reagent: The same as step one in example 1, to get Grignard reagent.

[0032] Step two, preparation of intermediate bromide sulfonium salt: The same as step two in example 1, to get intermediate bromide sulfonium salt (compound 1-2).

[0033] Step three, preparation of t-butyl-containing sulfonium salt photoacid generator: The intermediate bromide sulfonium salt (compound 1-2) 10.0 g obtained in step two and sodium perfluorobutylsulfonate 11.75 g were added to a 500 ml flask, 150 mL of ultrapure water was added, and the oil bath was heated to 80±2℃. The reaction was carried out for 2 hours. The reaction solution was cooled to room temperature, dichloromethane was added for extraction (3x50ml), and the organic phase was combined. The organic phase was washed with ultrapure water (3x50ml); rotary evaporation to dryness, and then recrystallized with methyl tert-butyl ether (150 mL); white crystal compound (compound 2-3) (yield: 95%, 12.7g) was obtained, which was t-butyl-containing sulfonium salt photoacid generator.

[0034] The structural characterization data of the white crystal compound obtained in this example are as follows: In 300MHz, DMSO 1 H-NMR δ (ppm): 7.45 (1H, s); 7.33-7.36 (10H, m); 7.16 (2H, s); 1.32 (18H, s).

[0035] LCMS: Cation 375; Anion 299.

[0036] From the above structural characterization data, it can be seen that the white crystal compound obtained in this example is the target product compound 2-3.

Claims

1. A thioonium salt-based photoacid-generating agent containing tert-butyl, characterized in that, The structural formula of thioonium salts containing tert-butyl is: ； In the formula: It is selected from trifluoromethanesulfonate or perfluorobutylsulfonate.

2. A method for preparing a tert-butyl-containing thioonium salt photoacid-generating agent as described in claim 1, characterized in that, This method is performed according to the following steps: Step 1, prepare Grignard reagent: 3,5-Di-tert-butylbromobenzene reacts with metallic magnesium to form the corresponding Grignard reagent; Step 2, preparation of the intermediate sulfonium bromide salt: Diphenyl sulfoxide reacts with reagent a to form a trimethylsilyl-substituted thioonium salt intermediate, which then reacts with the Grignard reagent obtained in step one. After acidification and crystallization, the intermediate thioonium bromide is formed. Step 3: Preparation of thioonium salt photoacid-generating agents containing tert-butyl groups: The intermediate thioonium bromide obtained in step two undergoes an ion exchange reaction with an anionic reagent, and after purification, a thioonium salt containing tert-butyl is obtained as a photoacid-generating agent.

3. The method for preparing the tert-butyl-containing thioonium salt photoacid-generating agent as described in claim 2, characterized in that, In step two, reagent a is trimethylchlorosilane.

4. The method for preparing the tert-butyl-containing thioonium salt photoacid-generating agent as described in claim 2, characterized in that, In step two, the acid used for acidification is hydrobromic acid.

5. The method for preparing the tert-butyl-containing thioonium salt photoacid-generating agent as described in claim 2, characterized in that, In step two, the solvent used for crystallization is methyl tert-butyl ether.

6. The method for preparing the tert-butyl-containing thioonium salt photoacid-generating agent as described in claim 2, characterized in that, In step three, the anionic reagent is sodium trifluoromethanesulfonate or sodium perfluorobutylsulfonate.

7. The method for preparing the tert-butyl-containing thioonium salt photoacid-generating agent as described in claim 2, characterized in that, In step three, the solvent for the ion exchange reaction is selected from water or dichloromethane.

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