A tin-containing polymerizable photoacid generator and its preparation method

Abstract

The present invention provides a tin-containing polymerizable photoacid generator, and the general formula of the tin-containing polymerizable photoacid generator is as follows: wherein, R1 is hydrogen or methyl, R2 is alkyl, fluoroalkyl, oxyalkyl, phenyl or fluorophenyl, and X + is a sulfonium cation or an iodonium cation. The present invention introduces a high extreme ultraviolet absorbing element Sn into the photoacid generator to achieve the purpose of improving the sensitivity of the photoresist.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymerizable photoacid generators, and particularly relates to a tin-containing polymerizable photoacid generator and a preparation method thereof. Background Art

[0002] Lithography technology refers to a microfabrication technology that transfers the pattern of a mask onto a substrate through processes such as exposure, development, etching, and stripping, using the principle of the photochemical reaction of a photoresist. A photoresist, also known as a photo resist, is the core basic material of the lithography process. A photoresist is a photosensitive material with corrosion resistance that can undergo a significant change in solubility under the irradiation of light sources such as ultraviolet light and electron beams. Chemically amplified photoresists mainly consist of a film-forming resin, a photoacid generator, a solvent, and other additives. After exposure, the photoacid generator decomposes to generate acid. During the post-baking process, the acid catalyzes the chemical reaction of acid-labile groups in the photoresist. After the catalytic reaction is completed, the acid is released again to continue catalyzing the chain reaction. Therefore, the required exposure energy can be significantly reduced, improving photosensitivity.

[0003] The photoacid generator is the core component in a chemically amplified photoresist, and its structure and properties have a great impact on the image formed by the photoresist system. The incompatibility between the small molecule photoacid generator and the resin will lead to uneven distribution of the photoacid generator. During the exposure and post-baking processes, it will cause uneven photochemical reactions in the exposed areas, and the diffusion of the photoacid after exposure will cause a large line edge roughness, reducing the resolution.

[0004] With the development of lithography technology, extreme ultraviolet lithography technology, i.e., lithography with a wavelength of 13.5 nm, has become the next-generation lithography technology. Due to the extremely short wavelength of the extreme ultraviolet lithography light source, the energy of a single photon is 92.48 eV, and the light source power is limited. It is urgent to solve the sensitivity of the photoresist. Summary of the Invention

[0005] To solve the above problems, the present invention provides a tin-containing polymerizable photoacid generator, and the general formula of the tin-containing polymerizable photoacid generator is as follows:

[0006]

[0007] Among them, R1 is hydrogen or methyl, R2 is an alkyl group, a fluoroalkyl group, an oxygen-containing alkyl group, a phenyl group, or a fluorophenyl group, and X + is a sulfonium cation or an iodonium cation.

[0008] According to an embodiment of the present invention, X + is one of the following formulas:

[0009]

[0010] Among them, R3, R4, R5, R6 and R7 are independently optionally substituted C 1-30 alkyl group, or a substituted carbocyclic aromatic group, or an unsubstituted carbocyclic aromatic group.

[0011] According to an embodiment of the present invention, any two or three of R3, R4 and R5 may be linked together to form a ring with sulfur.

[0012] According to an embodiment of the present invention, the X + is selected from one of the following groups:

[0013]

[0014] Among them, P1, P2, P3, P4, P5, P6 and P7 in the formula independently represent hydrogen or a 1-5 non-hydrogen substituent.

[0015] According to an embodiment of the present invention, the tin-containing polymerizable photoacid generator is selected from compounds having the following structures:

[0016] The present invention also provides a preparation method of the tin-containing polymerizable photoacid generator as described above, including the following synthesis steps:

[0017]

[0018] Among them, M is an alkali metal, Y is a halogen atom, R1 is hydrogen or methyl, R2 is an alkyl group, a fluoroalkyl group or an oxygen-containing alkyl group, a phenyl group or a fluorophenyl group, X + is a sulfonium cation or an iodonium cation;

[0019] The specific synthesis steps are as follows:

[0020] a) Preparation of intermediate II: Dibutyltin oxide I reacts with a sulfonate containing a hydroxyl group in a first solution to generate intermediate II;

[0021] b) Preparation of intermediate III: Intermediate II reacts with methacrylic acid or acrylic acid in a first solution to generate intermediate III;

[0022] c) Preparation of the tin-containing polymerizable photoacid generator: Intermediate III reacts with compound X + Y - in a second solution to carry out an ion exchange reaction to obtain the tin-containing polymerizable photoacid generator.

[0023] According to an embodiment of the present invention, M is K, Na or Li, Y is Cl or Br, and R2 is a fluoroalkyl group or a fluorophenyl group.

[0024] According to an embodiment of the present invention, in step a), it further includes at least one of the following technical features:

[0025] a1) The temperature of the reaction is 70°C to 80°C, and the reaction time is 8 to 24 hours;

[0026] a2) The molar ratio of dibutyltin oxide I to the sulfonate containing hydroxyl group is 1:1;

[0027] a3) The first solution is selected from one of methanol and toluene;

[0028] a4) The sulfonate containing hydroxyl group is selected from the following:

[0029]

[0030] According to an embodiment of the present invention, in step b), it further includes at least one of the following technical features:

[0031] b1) The temperature of the reaction is 0°C to 25°C, and the reaction time is 12 to 24 hours;

[0032] b2) The molar ratio of intermediate II to methacrylic acid or acrylic acid is 1:1;

[0033] b3) The first solution is selected from one of methanol and toluene.

[0034] According to an embodiment of the present invention, in step c), it further includes at least one of the following technical features:

[0035] c1) The temperature of the reaction is 0°C to 25°C, and the reaction time is 12 to 24 hours;

[0036] c2) The molar ratio of intermediate III to compound X + Y - is 1:(1 - 2);

[0037] c3) The second solution is a mixed solution of at least one of acetonitrile, acetone, methyl butanone, methyl isobutyl ketone, dichloromethane, chloroform, methanol, ethanol, methyl acetate, ethyl acetate, propyl acetate and water.

[0038] By introducing the high extreme ultraviolet absorption element Sn into the photoacid generator of the present invention, the compatibility problem between the photoacid generator and the resin can be solved, the diffusion problem of the photoacid generator during the post-exposure baking process can be solved, and the problems of low extreme ultraviolet absorption of the photoresist and low sensitivity of the photoresist can also be solved.

[0039] Of course, it is not necessary to achieve the above technical effects simultaneously in any solution of the present invention. Detailed implementation manners

[0040] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0041] The inventors found that current photoacid generators are almost only used in monomer form. The compatibility between small-molecule photoacid generators and resins is limited, and the acid generation efficiency highly depends on the compatibility between the photoacid generator and the resin. In addition, poor compatibility between small-molecule photoacid generators and resins can lead to phase separation, uneven acid distribution and migration, and these problems often result in undesired, premature and uneven deprotection reactions in photoresists. To alleviate these problems, the designed polymerizable photoacid generator is directly polymerized onto the resin. The photons corresponding to the wavelength of 13.5 nm of extreme ultraviolet light have an energy of 92 eV, which is much higher than the ionization energy of the atoms composing the photoresist material. This makes the initiation of chemical reactions in the photoresist change from simple photochemical radiation to ionization radiation generated by extreme ultraviolet-induced ionization of the material. In addition, the density of extreme ultraviolet photons is very low, and it is extremely crucial to improve the absorption efficiency of the photoresist for extreme ultraviolet photons. The absorption of extreme ultraviolet photons by the photoresist needs to comprehensively consider the absorption probabilities of different atoms, which is associated with the absorption cross-section data of the corresponding ionization radiation wavelength. The extreme ultraviolet absorption cross-sections of elements such as C, H, O, and N in the composition of traditional polymer photoresists are relatively low. Therefore, the EUV absorption efficiency of such photoresists is low, while elements such as metal Sn, metalloid Te, and halogen I have extremely high absorption cross-sections. Introducing these elements into the photoresist can significantly improve the absorption of EUV photons. Therefore, high extreme ultraviolet absorption element Sn is introduced into the photoacid generator to achieve the purpose of improving the sensitivity of the photoresist.

[0042] The present invention provides a tin-containing polymerizable photoacid generator and a preparation method thereof. This photoacid generator can be polymerized and bonded onto the resin, effectively preventing the diffusion of acid, improving the line edge roughness, enhancing the resolution, and also introducing tin element with high extreme ultraviolet absorption, improving the sensitivity and contrast of the photoresist. Moreover, the preparation method of this photoacid generator is simple and convenient, with a high yield.

[0043] The present invention provides a tin-containing polymerizable photoacid generator, and the general formula of the tin-containing polymerizable photoacid generator is as follows:

[0044]

[0045] Among them, R1 is hydrogen or methyl; R2 is alkyl, fluoroalkyl, oxyalkyl, phenyl or fluorophenyl, and X + is a sulfonium cation or an iodonium cation.

[0046] In one embodiment, X + is one of the following formulas:

[0047]

[0048] wherein R3, R4, R5, R6 and R7 are independently optionally substituted C 1-30 alkyl, or a substituted or unsubstituted carbocyclic aromatic group. In some embodiments, R2 is a fluoroalkyl or fluorophenyl group, and the more fluorine atoms there are or the closer the fluorine atoms are to the sulfonate group, the stronger the acidity of the acid generated by the photoacid generator after irradiation.

[0049] In one embodiment, any two or three of R3, R4 and R5 may be linked together to form a ring with sulfur.

[0050] In one embodiment, said X + is selected from one of the following groups:

[0051]

[0052] wherein P1, P2, P3, P4, P5, P6 and P7 in the formula independently represent hydrogen or a C1-C5 non-hydrogen substituent.

[0053] For example, said X + is selected from, but not limited to, one of the following structures:

[0054]

[0055] In some embodiments, R2 is a C1-C 18 alkyl, a perfluorinated or partially fluorinated C1-C 18 alkyl, a C6 phenyl, a perfluorinated or partially fluorinated phenyl.

[0056] In one embodiment, the tin-containing polymerizable photoacid generator is selected from, but not limited to, compounds having the following structures:

[0057]

[0058] The present invention also provides a method for preparing the tin-containing polymerizable photoacid generator as described above, comprising the following synthesis steps:

[0059]

[0060] wherein M is an alkali metal, Y is a halogen atom, R1 is hydrogen or methyl, R2 is alkyl, fluoroalkyl or oxyalkyl, phenyl or fluorophenyl, and X + is a sulfonium cation or an iodonium cation;

[0061] The specific synthesis steps are as follows:

[0062] a) Preparation of Intermediate II: An oxidation reaction occurs between dibutyltin oxide I and a sulfonate containing a hydroxyl group in a first solution to form Intermediate II;

[0063] b) Preparation of Intermediate III: An esterification reaction occurs between Intermediate II and methacrylic acid or acrylic acid in a first solution to form Intermediate III;

[0064] c) Preparation of a tin-containing polymerizable photoacid generator: Intermediate III reacts with Compound X + Y - in a second solution to undergo an ion exchange reaction to obtain the tin-containing polymerizable photoacid generator.

[0065] According to an embodiment of the present invention, M is K, Na or Li, Y is Cl or Br, and R2 is a fluoroalkyl or fluorophenyl.

[0066] In one embodiment, in step a), it further includes at least one of the following technical features:

[0067] a1) The temperature of the reaction is 70°C to 80°C, and the reaction time is 8 to 24 hours;

[0068] a2) The molar ratio of dibutyltin oxide I to the sulfonate containing a hydroxyl group is 1:1;

[0069] a3) The first solution is selected from one of methanol and toluene;

[0070] a4) The sulfonate containing a hydroxyl group is selected from the following:

[0071]

[0072] In one embodiment, in step b), it further includes at least one of the following technical features:

[0073] b1) The temperature of the reaction is 0°C to 25°C, and the reaction time is 12 to 24 hours;

[0074] b2) The molar ratio of Intermediate II to methacrylic acid or acrylic acid is 1:1;

[0075] b3) The first solution is selected from one of methanol and toluene.

[0076] According to an embodiment of the present invention, in step c), it further includes at least one of the following technical features:

[0077] c1) The temperature of the reaction is 0°C to 25°C, and the reaction time is 12 to 24 hours;

[0078] c2) Intermediate III and Compound X + Y- The molar ratio is 1:(1 to 2);

[0079] c3) The second solution is a mixed solution of at least one of acetonitrile, acetone, methyl butanone, methyl isobutyl ketone, dichloromethane, chloroform, methanol, ethanol, methyl acetate, ethyl acetate, propyl acetate and water.

[0080] This will be further illustrated below with specific examples.

[0081] Preparation of Tin-containing Polymerizable Photoacid Generator Ⅳ-1

[0082] The synthesis route is as follows:

[0083]

[0084] Preparation of Intermediate Ⅱ-1: Dibutyltin oxide Ⅰ (2.48 g, 10 mmol) and sodium 2,3,5,6-tetrafluoro-4-hydroxybenzenesulfonate (2.68 g, 10 mmol) were dissolved in methanol (150 mL), and heated under reflux at 70 °C for 8 hours. The solvent was removed under reduced pressure to obtain a white solid. The crude product was recrystallized from a mixture of methanol and deionized water (volume ratio 1:1) to obtain the corresponding Intermediate Ⅱ-1 (3.91 g, 7.56 mmol, 75.6%).

[0085] Preparation of Intermediate Ⅲ-1: Intermediate Ⅱ-1 (2.58 g, 5 mmol) was dissolved in methanol (80 ml), and methacrylic acid (0.43 g, 5 mmol) in 20 ml of methanol was added dropwise at room temperature over 30 minutes and stirred for 20 hours. The solvent was removed under reduced pressure to obtain a white solid. The crude product was recrystallized from a mixture of methanol and deionized water (volume ratio 1:1) to obtain the corresponding Intermediate Ⅲ-1 (2.63 g, 4.49 mmol, 89.8%).

[0086] Preparation of Tin-containing Polymerizable Photoacid Generator Ⅳ-1: Intermediate Ⅲ-1 (1.75 g, 3 mmol) and triphenylsulfonium chloride (1.2 g, 4 mmol) were dissolved in a mixed solvent of methanol (20 ml) and water (2 ml), stirred at room temperature for 12 hours, and the reaction solution was poured into ultrapure water to obtain a white precipitate. The precipitate was filtered, washed three times with ultrapure water (50 ml * 3), filtered, and the filter cake was dried to obtain Tin-containing Polymerizable Photoacid Generator Ⅳ-1 (2.05 g, 2.48 mmol, 82.6%).

[0087] Example 2

[0088] Preparation of Tin-containing Polymerizable Photoacid Generator Ⅳ-2

[0089] The synthesis route is as follows:

[0090]

[0091] Preparation of Intermediate Ⅱ-2: Dibutyltin oxide Ⅰ (2.48 g, 10 mmol) and sodium hydroxyethylsulfonate (1.48 g, 10 mmol) were dissolved in toluene (150 mL), and heated under reflux at 70 °C for 24 hours. The solvent was removed under reduced pressure to obtain a white solid. The crude product was recrystallized from a mixture of methanol and deionized water (volume ratio 1:1) to obtain the corresponding Intermediate Ⅱ-2 (3.65 g, 9.2 mmol, 92%).

[0092] Preparation of Intermediate Ⅲ-2: Intermediate Ⅱ-2 (1.98 g, 5 mmol) was dissolved in toluene, and methacrylic acid (0.43 g, 5 mmol) in 20 ml of toluene was added over 30 minutes at room temperature and stirred for 20 hours. The solvent was removed under reduced pressure to obtain a white solid. The crude product was recrystallized from a mixture of methanol and deionized water (volume ratio 1:1) to obtain the corresponding Intermediate Ⅲ-2 (2.09 g, 4.5 mmol, 90%).

[0093] Preparation of Tin-containing Polymerizable Photoacid Generator Ⅳ-2: Intermediate Ⅲ-2 (1.39 g, 3 mmol) and triphenylsulfonium chloride (1.2 g, 4 mmol) were dissolved in a mixed solvent of methanol (20 ml) and water (2 ml), stirred at room temperature for 12 hours, and the reaction solution was poured into ultrapure water to obtain a white precipitate. The precipitate was filtered and washed three times with ultrapure water (50 ml * 3), filtered, and the filter cake was dried to obtain Tin-containing Polymerizable Photoacid Generator Ⅳ-2 (1.83 g, 2.6 mmol, 86.6%).

[0094] Example 3

[0095] Preparation of Tin-containing Polymerizable Photoacid Generator Ⅳ-3

[0096] The synthesis route is as follows:

[0097]

[0098] The first two steps in Example 3 are exactly the same as the first two steps in Example 1.

[0099] Preparation of Tin-containing Polymerizable Photoacid Generator Ⅳ-3: Intermediate Ⅲ-1 (1.75 g, 3 mmol) and diphenyliodonium bromide (1.44 g, 4 mmol) were dissolved in a mixed solvent of methanol (20 ml) and water (2 ml), stirred at room temperature for 12 hours, and the reaction solution was poured into ultrapure water to obtain a white precipitate. The precipitate was filtered and washed three times with ultrapure water (50 ml * 3), filtered, and the filter cake was dried to obtain Tin-containing Polymerizable Photoacid Generator Ⅳ-3 (2.1 g, 2.5 mmol, 83.3%).

[0100] In the description of this specification, the descriptions with reference to the terms "an implementation", "an embodiment", "specific implementation process", "an example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A tin-containing polymerizable photoacid generator, characterized in that, The general formula of the tin-containing polymerizable photoacid generator is as follows: wherein, R1 is hydrogen or methyl, R2 is phenyl or fluorophenyl, and X + is a sulfonium cation or an iodonium cation; Said X + is selected from one of the following groups: Wherein, P1, P2, P3, P4, P5, P6 and P7 in the formula independently represent hydrogen or 1-5 non-hydrogen substituents.

2. The tin-containing polymerizable photoacid generator according to claim 1, wherein The tin-containing polymerizable photoacid generator is selected from compounds having the following structures:

3. A preparation method of a tin-containing polymerizable photoacid generator as described in claim 1, characterized in that, It includes the following synthesis steps: Among them, M is an alkali metal, Y is a halogen atom, R1 is hydrogen or methyl, R2 is phenyl or fluorophenyl, and X + is a sulfonium cation or an iodonium cation; Said X + is selected from one of the following groups: Wherein, P1, P2, P3, P4, P5, P6 and P7 in the formula independently represent hydrogen or 1-5 non-hydrogen substituents; a) Preparation of intermediate II: Dibutyltin oxide I reacts with a sulfonate containing a hydroxyl group in a first solution to form intermediate II; b) Preparation of intermediate III: Intermediate II undergoes an esterification reaction with methacrylic acid or acrylic acid in a first solution to form intermediate III; c) Preparation of a tin-containing polymerizable photoacid generator: Intermediate III and Compound X + Y - An ion exchange reaction is carried out in a second solution to obtain the tin-containing polymerizable photoacid generator as described in claim 1.

4. The preparation method according to claim 3, wherein M is K, Na or Li, and Y is Cl or Br.

5. The preparation method according to claim 3, characterized in that, In step a), it further includes at least one of the following technical features: a1) The temperature of the reaction is 70°C to 80°C, and the reaction time is 8 to 24 hours; a2) The molar ratio of dibutyltin oxide I to the sulfonate containing a hydroxyl group is 1:1; a3) The first solution is selected from one of methanol and toluene; a4) The sulfonate containing a hydroxyl group is selected from the following:

6. The preparation method according to claim 3, characterized in that, In step b), it further includes at least one of the following technical features: b1) The temperature of the reaction is 0°C to 25°C, and the reaction time is 12 to 24 hours; b2) The molar ratio of intermediate II to methacrylic acid or acrylic acid is 1:1; b3) The first solution is selected from one of methanol and toluene.

7. The preparation method according to claim 3, characterized in that, In step c), it further includes at least one of the following technical features: c1) The temperature of the reaction is 0°C to 25°C, and the reaction time is 12 to 24 hours; c2) The intermediate III and compound X + Y - have a molar ratio of 1:(1 - 2); c3) The second solution is a mixed solution of at least one of acetonitrile, acetone, methyl butanone, methyl isobutyl ketone, dichloromethane, chloroform, methanol, ethanol, methyl acetate, ethyl acetate, propyl acetate and water.

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