Alkyl tin-containing derivative, photoresist composition, preparation method and application

Abstract

The invention discloses a preparation method and application of a photoresist composition containing an alkyl tin derivative. The alkyl tin derivative contains 2-8 tin atoms, adding a ligand into the tin source solution, uniformly mixing, and heating a tin-containing reaction system to generate the alkyl tin derivative; stopping heating, filtering and collecting a filter cake or performing rotary evaporation on reaction liquid to obtain solid powder. The product disclosed by the invention has relatively high etching resistance and extreme ultraviolet absorption capacity, has enough thermal stability, is suitable for the requirements of an extreme ultraviolet lithography processing technology, is simple in preparation process and is suitable for industrial application.

Description

Technical Field

[0001] This invention belongs to the field of materials technology, specifically relating to a method for preparing an alkyltin derivative with high tin content and solubility transformation characteristics, and the application of photoresist prepared with it as the main material in photolithography, particularly deep ultraviolet lithography, electron beam lithography and extreme ultraviolet lithography. Background Technology

[0002] Photolithography plays a crucial role in the integrated circuit (IC) industry. Over the past 50 years, photolithography has matured significantly, enhancing its ability to create extremely small features. As predicted by Moore's Law, IC density has grown exponentially, with feature sizes shrinking to below 20 nanometer half-pitch. Furthermore, extreme ultraviolet (EUV) lithography has proven to be a powerful and promising method for further improving resolution. However, it requires complex and very expensive instrumentation, and the only reliable EUV exposure tools on the market are those from ASML. Electron beam lithography (EBL) is an advanced photolithography technique that creates high-precision patterns on a substrate by directly exposing photoresist with a focused electron beam. By using a series of focusing lenses and beam deflection coils, its spot size can be less than 5 nanometers. Therefore, patterns smaller than 10 nanometers can be fabricated using EBL. Due to its maskless nature and flexible design capabilities, EBL is becoming increasingly important in micro- and nano-fabrication technologies.

[0003] Currently, photolithography materials are mainly classified into three categories: polymer-based, molecular glass-based, and metal-based photoresists. In polymer-based photoresists, the polymer chain size is generally between 6nm and 10nm, which inevitably results in a roughness of 3nm to 5nm or even higher in the lithographic pattern, severely impacting lithography process nodes of 30nm and below. This factor makes polymer-based photoresists difficult to meet the practical requirements of extreme ultraviolet (EUV) lithography technology. Metal-based photoresists, using metal oxide clusters or organometallic compounds as the main material, typically have a molecular size below 5nm, thus helping to reduce the roughness of the lithographic pattern and improve the photoresist resolution.

[0004] Research on high-performance organotin compound photoresists is receiving increasing attention. The photolithography process of organotin compound photoresists mainly involves two steps: radiation-induced decomposition of organic groups, and subsequent metal-oxygen crosslinking. Therefore, organotin compound photoresists are often used as negative photoresists. However, the single crosslinking mechanism limits the sensitivity of organotin compound photoresists. In a study on organotin cages, researchers proposed a simplified model and estimated that, on average, each organotin cage requires approximately 10 low-energy electrons to induce a sufficient solubility transition in the photoresist to reveal a pattern. However, currently, most organotin compound photoresist lithography is limited to the tin-oxygen crosslinking process caused by the breaking of tin-carbon bonds, and its sensitivity still needs further improvement. Summary of the Invention

[0005] The first technical problem to be solved by this invention is to provide an alkyltin derivative. This alkyltin derivative has sufficient thermal stability to meet the requirements of photolithography processes; in addition, it has good solubility in some common solvents and can be spin-coated onto the surface of a silicon wafer to form a uniform and flat film.

[0006] The second technical problem to be solved by this invention is to provide a method for preparing the above-mentioned alkyltin derivatives. This method uses one or more of alkyltin chloride, alkyltin oxide, hydroxyalkyltin chloride, and alkylstannic acid as a tin source to directly react with carboxylic acid ligands to prepare a series of alkyltin-based derivatives in one step. The synthesis process is simple, and the products can be separated from the system by filtration or rotary evaporation under reduced pressure.

[0007] The third technical problem to be solved by the present invention is to provide the application of photoresist with the above-mentioned alkyl tin derivative as the main material in electron beam lithography.

[0008] The technical solution adopted in this invention is: I. An alkyltin derivative, to solve the first technical problem mentioned above, the alkyltin derivative of the present invention has the following molecular structure: This structure uses dicarboxylic acid Rn and alkyltin Rn Sn It is a repeating unit, and the molecule is linear or cyclic.

[0009] The dicarboxylic acid Rn mentioned above includes the following: Carboxylic acid ligands are dicarboxylic acids with ≤12 carbon atoms, and their structures are as follows: Among them, C n =C 1~12 Saturated or unsaturated hydrocarbon groups; Or a derivative of isophthalic acid, with the following structure: R1 to R4 are hydrogen atoms, halogen atoms, hydroxyl groups, methoxy groups, or vinyl groups; the substituents R1 to R4 may be the same or different; Or a phthalic acid derivative, with the following structure: R1 to R4 are hydrogen atoms, halogen atoms, hydroxyl groups, methoxy groups, or vinyl groups; the substituents R1 to R4 may be the same or different; Or a terephthalic acid derivative, with the following structure: R1 to R4 are hydrogen atoms, halogen atoms, hydroxyl groups, methoxy groups, or vinyl groups; the substituents R1 to R4 may be the same or different.

[0010] The alkyltin R Sn It is selected from one or more of alkyl tin chloride, alkyl tin oxide, hydroxyalkyl tin chloride, and alkyl stannic acid.

[0011] II. A method for preparing an alkyltin derivative, comprising the following steps: Provide or prepare a tin source solution, the tin source solution comprising a first solvent and a tin source dispersed in the first solvent; The ligand is added to the tin source solution and mixed evenly to prepare a tin-containing reaction system; The tin-containing reaction system is heated, and the heating temperature is controlled at 20℃~120℃, so that alkyltin derivatives are generated in the tin-containing reaction system. Stop heating, collect the filter cake by filtration or obtain a solid powder by rotary evaporation of the reaction liquid, and obtain the alkyltin derivative.

[0012] The tin source is selected from one or more of alkyl tin chloride, alkyl tin oxide, hydroxyalkyl tin chloride, and alkyl stannic acid; The first solvent is selected from one or more of alcohol solvents, ester solvents, hydrocarbon solvents, and benzene solvents; The ligands are selected from carboxylic acid ligands.

[0013] In the tin source solution, all tin sources are dissolved with a minimum amount of solvent.

[0014] In the tin-containing reaction system, the molar ratio of tin atoms in the tin source to the ligand is 1:(0.1-10); During the heating of the tin-containing reaction system, the tin-containing reaction system is reacted at a temperature of 20℃ to 120℃ for 12h to 48h.

[0015] After allowing the sample to stand until solid components precipitate, the process further includes filtering to obtain the liquid components and then rotary drying and drying the sample.

[0016] After the reaction is complete, the solid component is obtained either by filtration and drying, or by rotary evaporation under reduced pressure to remove excess solvent and drying.

[0017] III. An alkyltin derivative prepared by the above-described method.

[0018] This invention provides the application of photoresist based on the above-mentioned alkyl tin derivative as the main material in photolithography, and the photoresist can be used as a negative photoresist.

[0019] IV. A photoresist composition, wherein the photoresist composition is a negative photoresist, comprising: a second solvent and a photosensitizer and a photoresist material dispersed in the second solvent, wherein the photoresist material comprises the above-mentioned alkyl tin derivative; wherein in the photoresist composition, the weight percentage of the photoresist material is 0.1% to 15%, the weight percentage of the photosensitizer is 0.005% to 1.5%, and the remainder is the photoresist solvent.

[0020] In a specific implementation, the photoresist is spin-coated onto a silicon wafer to form a film, thereby forming a photoresist coating.

[0021] This invention also discloses the application of photoresists based on the above-mentioned alkyl tin derivatives in photolithography.

[0022] V. Application of photoresist compositions in the preparation of micro and nanostructures.

[0023] When fabricating micro- and nano-structures, ultraviolet lithography, deep ultraviolet lithography, extreme ultraviolet lithography, electron beam lithography, or multiphoton lithography are used for exposure.

[0024] The above photoresist formulation may also include other auxiliary additives, such as sensitizers, surfactants, crosslinking agents, and stabilizers.

[0025] The photoresist of this invention is spin-coated onto a silicon wafer using a spin coater to form a photoresist coating. A dense line array pattern with a line width as narrow as 37.2 nm can be obtained by electron beam lithography.

[0026] This invention enhances the sensitivity of photoresists by introducing radiation-induced crosslinkable carbon-carbon double bonds into organotin compound molecules. Three types of crosslinked organotin compounds are synthesized: an organotin-based cyclic trimer using dibutyltin oxide and 5-vinyl isophthalic acid, an organotin-based cyclic dimer using dibutyltin oxide and maleic acid, and a dibutyltin dichloride and sodium methacrylate using dibutyltin dimethacrylate.

[0027] The alkyltin derivatives of this invention are alkyltin derivatives containing 2 to 8 tin atoms, which have high etching resistance and extreme ultraviolet absorption capacity, and are suitable for the requirements of extreme ultraviolet lithography processing.

[0028] The preparation method of this alkyltin derivative includes the following steps: providing or preparing a tin source solution, wherein the tin source solution includes a first solvent and a tin source dispersed in the first solvent; adding a ligand to the tin source solution and mixing evenly to prepare a tin-containing reaction system; heating the tin-containing reaction system and controlling the heating temperature to 20℃~120℃ to generate the alkyltin derivative in the tin-containing reaction system; stopping heating and collecting the filter cake by filtration or obtaining a solid powder by rotary evaporation of the reaction liquid. This preparation process is simple and suitable for industrial application.

[0029] The beneficial effects of this invention are: This invention enhances the sensitivity of photoresist by introducing radiation-induced crosslinkable carbon-carbon double bonds into organotin compound molecules, thus solving the problem of tin-oxygen crosslinking caused by the breaking of tin-carbon bonds in existing organotin compound photoresists and improving the performance of photoresists. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the hydrogen NMR spectrum obtained in Example 1.

[0031] Figure 2 This is a schematic diagram of the mass spectrometry obtained in Example 1.

[0032] Figure 3 This is a schematic diagram of the hydrogen NMR spectrum obtained in Comparative Example 1.

[0033] Figure 4 This is a schematic diagram of the mass spectrometry obtained in Comparative Example 1.

[0034] Figure 5 This is a schematic diagram of the hydrogen NMR spectrum obtained in Example 2.

[0035] Figure 6 This is a schematic diagram of the mass spectrometry obtained in Example 2.

[0036] Figure 7 The graph shows the thermal stability results under weightlessness in Example 2.

[0037] Figure 8 This is a schematic diagram of the elongated lines of the photoresist in Example 2. Detailed Implementation

[0038] To facilitate understanding of the present invention, a more comprehensive description is provided below. Preferred embodiments of the invention are shown herein. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items. The term “more” as used herein includes two or more items. The term “above a certain number” as used herein should be understood as a number and a range greater than a certain number.

[0040] Unless otherwise shown or indicated in the operational embodiments, all figures used to represent the amounts, physicochemical properties, etc., of ingredients in the specification and claims are to be understood to be adjusted by the term "about" in all cases. For example, therefore, unless stated to the contrary, the numerical parameters listed in the foregoing specification and appended claims are approximations, and those skilled in the art can appropriately modify these approximations to obtain the desired characteristics by utilizing the teachings disclosed herein. The use of numerical ranges indicated by endpoints includes all numbers within that range and any range within that range; for example, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4, and 5, etc.

[0041] To facilitate understanding and implementation of the present invention, the following more specific and detailed embodiments and comparative examples are provided for reference. Through the description and performance results of the following specific embodiments and comparative examples, the various embodiments of the present invention and their advantages will become apparent.

[0042] Unless otherwise specified, the raw materials used in the following embodiments can all be purchased from the market.

[0043] The embodiments of the present invention are as follows: Example 1: Photoresist composition based on organotin cyclic dimer (one) The synthesis of the organotin cyclic dimer (compound A) is as follows: Dissolve 0.5019 g (2.0 mmol) of dibutyltin oxide in 20 mL of anhydrous methanol, and heat with stirring to 60 °C; Then 0.2353 g (2.0 mmol) of maleic acid was added to the solution, and the reaction system was a colorless and transparent solution. The reaction was carried out at 65°C for 12 h and then cooled to room temperature. After the reaction solution was rotary evaporated at room temperature, the solid phase was collected and dried in a vacuum oven at 60 °C to obtain product compound A, which was then stored in a refrigerator.

[0044] pass 1 Compound A was characterized by 1H NMR and mass spectrometry, and the 1H NMR spectrum is as follows: Figure 1 As shown; mass spectrometry results are as follows Figure 2 As shown, a signal was found at a mass-to-charge ratio of 719.0660 in the mass spectrum of compound A sample. This can be attributed to compound A containing a sodium cation, which is consistent with its theoretical value (C). 24 H 40 O8Sn2+Na + The result (719.07) matches, proving the successful synthesis of compound A. (two) Photoresist composition: (1) Main material: organotin cyclic dimer (compound A) 30.0 mg (2) Solvent: 1 mL of propylene glycol methyl ether acetate The photoresist was prepared as follows: 30.0 mg of compound A was weighed and dissolved in 1 mL of propylene glycol methyl ether acetate. The mixture was sonicated for 20 min and then filtered through filter membranes with pore sizes of 0.45 μm and 0.22 μm to remove other impurities, thus obtaining photoresist of compound A.

[0046] Comparative Example 2: Photoresist composition based on dibutyltin dimethacrylate (one) The synthesis of the organotin cyclic dimer (compound A) is as follows: In a 100 mL flask, 0.3064 g (1.0 mmol) of dibutyltin dichloride was dissolved in 5 mL of anhydrous ethanol and heated to 40 °C with stirring. This solution is denoted as solution A. 0.2279 g (2.1 mmol) of sodium methacrylate was dissolved in 30 mL of anhydrous ethanol and stirred until dissolved. This solution is denoted as solution B. Solution B was added dropwise to solution A. A white precipitate was observed to gradually appear in the reaction system. The reaction was carried out at 40 °C for 12 h and then cooled to room temperature. The suspension was filtered, and the filtrate was evaporated by rotary evaporation at room temperature. The filtrate was then dried in a vacuum oven at 40 °C to obtain a white solid powder, namely product compound B, which was stored in a refrigerator.

[0047] pass 1 Compound B was characterized by 1H NMR, and the 1H NMR spectrum is as follows: Figure 3 As shown. To further confirm the successful synthesis of BTMA, compound B was analyzed by MS, and the test results are as follows. Figure 4 As shown. A signal was found at a mass-to-charge ratio of 427.0899 in the mass spectrum of compound B sample. This can be attributed to compound B containing a sodium cation, consistent with the theoretical value for compound B (C). 16 H 28 O4Sn+Na + = 427.09), which corroborates the successful synthesis of compound B. (two) Photoresist composition: (1) Main material: dibutyltin dimethacrylate (compound B) 30.0 mg (2) Solvent: 1 mL of propylene glycol methyl ether acetate The BTMA photoresist was prepared as follows: 30.0 mg of compound B was weighed and dissolved in 1 mL of propylene glycol methyl ether acetate. The solution was sonicated for 20 min, and then filtered sequentially through filter membranes with pore sizes of 0.45 μm and 0.22 μm to remove other impurities, yielding the compound B photoresist. The obtained photoresist was stored away from light.

[0049] Example 2: Photoresist composition based on organotin cyclic trimer (one) The synthesis of the organotin cyclic trimer (compound C) is as follows: 0.4999 g (2.0 mmol) of dibutyltin oxide was dissolved in 20 mL of toluene and heated to 60 °C with stirring. Then, 0.3868 g (2.0 mmol) of 5-vinylisophthalic acid was added to the solution, and the reaction system was a yellow suspension. After reacting at 60 °C for 12 h, the mixture was cooled to room temperature, the suspension was filtered, and the filter cake was collected. The filter cake was dried in a vacuum oven at 60 °C to obtain a white solid powder, namely product compound C, which was then stored in a refrigerator.

[0050] pass 1 Compound C was characterized by 1H NMR, and its 1H NMR spectrum is shown below. Figure 5 As shown. To further confirm the successful synthesis of BTMA, compound C was analyzed by MS, and the test results are as follows. Figure 6 As shown, a signal was found at a mass-to-charge ratio of 1291.2023 in the mass spectrum of compound C sample. This can be attributed to compound C containing a sodium cation, which is consistent with the theoretical value (C). 54 H 72 O 12 Sn3+Na + = 1291.20), which corroborates the successful synthesis of compound C. (two) Photoresist composition: (1) Main material: organotin cyclic trimer (compound C) 30.0 mg (2) Solvent: 1 mL of propylene glycol methyl ether acetate The photoresist of compound C was prepared as follows: 30.0 mg of compound C was weighed and dissolved in 1 mL of propylene glycol methyl ether acetate. The solution was sonicated for 20 min, and then filtered sequentially through 0.45 μm and 0.22 μm pore sizes to remove impurities, yielding the photoresist of compound C. The obtained photoresist was stored away from light. The initial weight loss of compound C was 5 wt% at 323 ℃ (see [link to product description]). Figure 7 It possesses good thermal stability and is suitable for application in various semiconductor manufacturing processes. For example... Figure 8 As shown, the photoresist obtained in this experimental example can fabricate thin lines with linewidths as narrow as about 37 nm. The high resolution is due to the molecular structure design of the organotin compound, demonstrating the superiority of the photoresist obtained based on Example 3 of this invention.

[0052] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An alkyltin derivative, characterized in that, The alkyltin derivatives have the following molecular structures: This structure uses dicarboxylic acid Rn and alkyltin Rn Sn It is a repeating unit, and the molecule is linear or cyclic.

2. An alkyltin derivative according to claim 1, characterized in that, The dicarboxylic acid Rn mentioned above includes the following: Carboxylic acid ligands are dicarboxylic acids with ≤12 carbon atoms, and their structures are as follows: Among them, C n =C 1~12 Saturated or unsaturated hydrocarbon groups; Or a derivative of isophthalic acid, with the following structure: R1 to R4 are hydrogen atoms, halogen atoms, hydroxyl groups, methoxy groups, or vinyl groups; the substituents R1 to R4 may be the same or different; Or a phthalic acid derivative, with the following structure: R1 to R4 are hydrogen atoms, halogen atoms, hydroxyl groups, methoxy groups, or vinyl groups; the substituents R1 to R4 may be the same or different; Or a terephthalic acid derivative, with the following structure: R1 to R4 are hydrogen atoms, halogen atoms, hydroxyl groups, methoxy groups, or vinyl groups; the substituents R1 to R4 may be the same or different.

3. An alkyltin derivative according to claim 1, characterized in that, The alkyltin R Sn It is selected from one or more of alkyl tin chloride, alkyl tin oxide, hydroxyalkyl tin chloride, and alkyl stannic acid.

4. A method for preparing an alkyltin derivative according to any one of claims 1-3, characterized in that, Includes the following steps: Provide or prepare a tin source solution, the tin source solution comprising a first solvent and a tin source dispersed in the first solvent; The ligand is added to the tin source solution and mixed evenly to prepare a tin-containing reaction system; The tin-containing reaction system is heated, and the heating temperature is controlled at 20℃~120℃, so that alkyltin derivatives are generated in the tin-containing reaction system. Stop heating, collect the filter cake by filtration or obtain a solid powder by rotary evaporation of the reaction liquid, and obtain the alkyltin derivative.

5. The method for preparing the alkyltin derivative according to claim 4, characterized in that, The tin source is selected from one or more of alkyl tin chloride, alkyl tin oxide, hydroxyalkyl tin chloride, and alkyl stannic acid; The first solvent is selected from one or more of alcohol solvents, ester solvents, hydrocarbon solvents, and benzene solvents; The ligands are selected from carboxylic acid ligands.

6. The method for preparing the alkyltin derivative according to claim 5, characterized in that, In the tin-containing reaction system, the molar ratio of tin atoms in the tin source to the ligand is 1:(0.1-10); During the heating of the tin-containing reaction system, the tin-containing reaction system is reacted at a temperature of 20℃ to 120℃ for 12h to 48h.

7. The method for preparing the alkyltin derivative according to claim 6, characterized in that, After the reaction is complete, the solid component is obtained by filtration and dried, or the excess solvent is removed by rotary evaporation under reduced pressure and then dried.

8. An alkyltin derivative, characterized in that, It is prepared by the preparation method according to any one of claims 4 to 7.

9. A photoresist composition, characterized in that, The photoresist composition is a negative photoresist, comprising: a second solvent and a photosensitizer and a photoresist material dispersed in the second solvent, wherein the photoresist material comprises any one of claims 1-3 or the alkyltin derivative of claim 8; In the photoresist composition, the weight percentage of the photolithographic material is 0.1% to 15%, the weight percentage of the photosensitizer is 0.005% to 1.5%, and the remainder is photoresist solvent.

10. The application of the photoresist composition according to claim 9, characterized in that, Applications in the fabrication of micro and nanostructures.

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