Photosensitive ArF resin monomer, resin, preparation method of resin and photoresist composition

Abstract

The invention provides a photosensitive ArF resin monomer, resin, a preparation method of the resin and a photoresist composition, and can be applied to the technical field of micro-nano processing and photoresist. The resin monomer is based on a cholic acid o-nitrobenzyl ester structure, has the characteristic of direct photolysis reaction under the wavelength of 193nm, and realizes a non-chemical amplification mechanism, so that the problem of graph quality caused by uncontrollable acid diffusion in traditional chemical amplification glue is avoided. The photoresist resin is prepared by copolymerizing a photosensitive monomer, an adamantane (methyl) acrylate monomer and a lactone (methyl) acrylate monomer, and has high etching resistance, good development contrast and substrate adhesion. The photoresist composition based on the resin does not need to add a photoacid generator, is simple and uniform in component, is suitable for dry ArF photoetching, immersion photoetching and other advanced photoetching processes, and has an important application prospect in semiconductor manufacturing and micro-nano device processing.

Description

Technical Field

[0001] This disclosure relates to the fields of micro / nano fabrication and photoresist technology, and more specifically to a photosensitive ArF resin monomer, resin, preparation method thereof, and photoresist composition. Background Technology

[0002] Photolithography is a core process in semiconductor manufacturing, and the performance of its core material, photoresist, directly determines the precision and quality of the pattern. For 193nm wavelength (ArF) photolithography, chemically amplified photoresists are traditionally employed. These photoresists typically consist of polymer resin, photoacid generators, alkaline quenchers, and solvents. The core mechanism lies in the photoacid generator absorbing a small number of photons during exposure to produce acid. This acid acts as a catalyst during the baking process after exposure, triggering a chain reaction of decomposition or cross-linking of the resin matrix, thus achieving a significant difference in solubility between the exposed and unexposed areas. This "chemical amplification" effect greatly improves photon utilization efficiency, giving the photoresist high sensitivity and high resolution, meeting the requirements of low-dose exposure.

[0003] However, while pursuing high performance, chemically amplified photoresists have also revealed some inherent technical shortcomings. First, because the system contains multiple components with different polarities and functions (such as resins and photoacid generators), compatibility issues may arise between these components, leading to uneven distribution within the photoresist film and affecting the uniformity and stability of the film formation. Second, and more critically, the acid generated after exposure undergoes lateral diffusion in subsequent process steps (especially the post-baking step). This acid diffusion behavior is difficult to control precisely, easily leading to deviations in critical dimensions from the design, increased line edge roughness, and even pattern bridging or collapse, severely restricting its application in more advanced processes (such as nodes below 14nm) and limiting pattern quality.

[0004] To overcome the aforementioned problems caused by chemical amplification mechanisms, research on non-chemically amplified photoresists has received increasing attention. Non-chemically amplified photoresists directly rely on photochemical reactions (such as photolysis, photocrosslinking, photorearrangement, or isomerization) of the photosensitive groups inherent in the resin during exposure to alter solubility, thus eliminating the need for photoacid-generating agents and complex catalytic processes. This mechanism fundamentally avoids acid diffusion problems and simplifies the composition, potentially leading to more uniform films and clearer pattern contours. However, developing non-chemically amplified photoresists suitable for ArF wavelengths faces significant challenges: most practically valuable photosensitive groups or polymer backbones exhibit strong absorption around 193 nm, resulting in decreased photoresist transmittance, insufficient exposure depth, and the inability to form high aspect ratio patterns.

[0005] On the other hand, as integrated circuit manufacturing processes continue to shrink, photoresists play an increasingly important role as masks in subsequent processes such as plasma etching, placing extremely high demands on their etching resistance. Currently, mainstream ArF photoresist resin systems each have their limitations: for example, poly(meth)acrylate resins have excellent transmittance at 193nm, but their aliphatic backbone structure leads to poor resistance to dry etching; maleic anhydride copolymers, while exhibiting good etching resistance, have high backbone rigidity, making them prone to hygroscopic hydrolysis after film formation, resulting in insufficient stability; polynorbornene derivatives can improve etching resistance by introducing a cyclic rigid structure, but their polymerization process is usually complex, and the tunability of monomer and polymer structures and the control of solubility face challenges. Therefore, how to synergistically solve the two core challenges of high photosensitivity and excellent etching resistance of ArF photoresists under non-chemical amplification mechanisms has become a key technological bottleneck that urgently needs to be overcome in this field. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] To address the issues of uneven component distribution, uncontrollable acid diffusion, and poor etching resistance in traditional 193nm chemically amplified photoresists, this disclosure provides a photosensitive ArF resin monomer, resin, and its preparation method, as well as a photoresist composition. By designing a monomer containing the photosensitive group of o-nitrobenzyl cholic acid, a non-chemically amplified photosensitivity mechanism of the photoresist is achieved, avoiding the acid diffusion process; and by introducing adamantyl groups and lactone units, the etching resistance, development contrast, and substrate adhesion of the photoresist are synergistically improved.

[0008] (II) Technical Solution

[0009] To address the aforementioned technical problems, embodiments of this disclosure provide a photosensitive ArF resin monomer, a resin, a method for preparing the same, and a photoresist composition.

[0010] According to the first aspect of this disclosure, a photosensitive ArF resin monomer is provided, the molecular structure of which is shown in Formula I:

[0011] Formula I

[0012] In this substituent, R1, R2, and R3 are independently selected from -H and -OH; R4, R5, R6, and R7 are independently selected from -H, -NO2, -CN, -CF3, -CHF2, -C2F5, -C4F9, -OH, halogen, C 1-12 Alkyl, C 1-12 Alkyl groups, -SO3H, -SO2C 1-12 -SO2N(C 1-12 Alkyl group 2, -SO2CF3, -CHO, -COC1-12 Alkyl, -COOC 1-12 Alkyl, -CON(C) 1-12 Alkyl groups, -COOH, -B(OH)2, -B(OR)2, -C≡CH, -CH=CH-CN, and C 1-12 One of the haloalkyl groups.

[0013] According to a second aspect of this disclosure, a method for preparing the above-mentioned photosensitive ArF resin monomer is provided, comprising: step S1, reacting cholic acid with an acyl chloride reagent in the presence of a first catalyst to obtain cholic acid chloride; step S2, esterifying cholic acid chloride with o-nitrobenzyl alcohol in a first organic solvent in the presence of a first organic base to obtain o-nitrobenzyl cholate; and step S3, esterifying o-nitrobenzyl cholate with methacryloyl chloride in a second organic solvent in the presence of a second catalyst and a second organic base to obtain o-nitrobenzyl cholate of methacrylate as shown in Formula I.

[0014] In some exemplary embodiments, in step S1, the acyl chloride reagent is sulfoxide and the first catalyst is N,N-dimethylformamide; in step S2, the first organic base is pyridine and the first organic solvent is dichloromethane; in step S3, the second catalyst is 4-dimethylaminopyridine, the second organic base is pyridine and the second organic solvent is dichloromethane.

[0015] According to a third aspect of this disclosure, a method for preparing a photosensitive ArF photoresist resin is provided, comprising: dissolving the photosensitive ArF resin monomer, adamantane (meth)acrylate monomer, lactone (meth)acrylate monomer, and free radical initiator as claimed in claim 1 in an organic solvent under an inert atmosphere, and carrying out a polymerization reaction at 60-70°C for 20-28 hours; after the reaction is completed, dropping the reaction solution into an antisolvent to precipitate the precipitate, collecting the precipitate and repeating the dissolution and precipitation process multiple times, and finally drying to obtain the photosensitive ArF photoresist resin.

[0016] According to a fourth aspect of this disclosure, a photosensitive ArF photoresist resin prepared by the above-described preparation method is provided. The ArF photoresist resin is a terpolymer formed by copolymerizing the above-described photosensitive ArF resin monomer, adamantane (meth)acrylate monomer, and lactone (meth)acrylate monomer. The molecular structure of the ArF photoresist resin is shown in Formula II.

[0017] Formula II

[0018] In this substituent, R1, R2, and R3 are independently selected from -H and -OH; R4, R5, R6, and R7 are independently selected from -H, -NO2, -CN, -CF3, -CHF2, -C2F5, -C4F9, -OH, halogen, C1-12 alkyl, C 1-12 alkoxy, -SO3H, -SO2C 1-12 , -SO2N(C 1-12 alkyl)2, -SO2CF3, -CHO, -COC 1-12 alkyl, -COOC 1-12 alkyl, -CON(C 1-12 alkyl)2, -COOH, -B(OH)2, -B(OR)2, -C≡CH, -CH=CH-CN and C 1-12 haloalkyl; R8 is a substituent on the adamantyl group, n represents the number of R8 substituents, and the n R8 substituents are independently selected from hydrogen, amino, di(C 1-12 alkyl)amino, C 1-12 alkylamino, cyano, isocyanate, isothiocyanate, carboxyl, C 1-15 alkoxycarbonyl, hydroxy, halogen, C 1-12 alkylamino, amido, azido, mercapto, acylhalide, C 1-12 alkyl, C 1-12 alkoxy, C 1-12 haloalkyl, C 3-20 cycloalkyl, C 1-12 alkylcarbonyl and C 6-20 arylcarbonyl, wherein n is a positive integer and 1 ≤ n ≤ 5; and A is a lactone structural unit.

[0019] In some exemplary embodiments, in Formula II, x, y, and z respectively represent the molar mass percentages of the corresponding monomers, where 0 < x ≤ 80%, 0 < y ≤ 80%, and 20% ≤ z ≤ 40%, and x + y + z = 100%.

[0020] In some exemplary embodiments, the lactone structural unit is selected from one of the structures shown in Formula III, Formula IV, and Formula V,

[0021] Formula III

[0022] Formula IV

[0023] Formula V

[0024] where * is the connection site; Ra, Rb, Rc, Rd, Re, Rf, Rg, Rh, and Ri are independently selected from hydrogen, amino, di(C 1-12 alkyl)amino, C 1-12 alkylamino, cyano, isocyanate, isothiocyanate, carboxyl, hydroxy, halogen, C 1-12 alkylamino, amido, azido, mercapto, acylhalide, C1-12 Alkyl, C 1-12 Alkoxy, C 1-12 Halogenated alkyl and C 1-12 One of the alkyl carbonyl groups.

[0025] In some exemplary embodiments, the structure of the photosensitive ArF photoresist resin is selected from any of the following structural formulas:

[0026] ;

[0027] ;

[0028] .

[0029] According to a fifth aspect of this disclosure, a photoresist composition is provided, comprising: the above-described photosensitive ArF photoresist resin; and an organic solvent; wherein, based on the total mass of the photoresist composition, the mass percentage of the photosensitive ArF photoresist resin is 4% to 6%.

[0030] In some exemplary embodiments, the photoresist composition further includes a leveling agent; the leveling agent is selected from fluorinated polyester type or polyether modified siloxane leveling agents; and the leveling agent has a mass percentage of 0.01% to 0.02% based on the total mass of the photoresist composition.

[0031] Furthermore, this disclosure also provides applications of the above-mentioned photoresist composition for use in 193nm interference lithography, 365nm interference lithography, 193nm projection lithography, 248nm projection lithography, 365nm projection lithography, 193nm SP lithography, 248nm SP lithography, 365nm SP lithography, or 193nm immersion lithography.

[0032] (III) Beneficial Effects

[0033] As can be seen from the above technical solutions, the photosensitive ArF resin monomer, resin and its preparation method, and photoresist composition provided in this disclosure have at least the following beneficial effects:

[0034] (1) By introducing o-nitrobenzyl cholic acid as a photosensitive group, the ester group undergoes photolysis under ArF exposure to directly generate a carboxyl group and achieve polarity conversion without relying on photoacid generators and acid catalysis. This fundamentally avoids the problems of pattern distortion and increased line width roughness caused by uncontrollable acid diffusion in traditional chemical amplification adhesives, and significantly improves pattern quality and process stability.

[0035] (2) The photosensitive ArF resin monomer has a rigid steroid skeleton of cholic acid structure and benzene ring structure. At the same time, adamantyl groups are introduced through copolymerization. The three work together to enhance the rigidity and structural density of the resin, effectively resisting physical and chemical erosion in the plasma etching environment, and overcoming the defect of poor etching resistance of traditional poly(meth)acrylate resins.

[0036] (3) By adopting a non-chemical amplification mechanism, no photoacid generator needs to be added to the photoresist composition, which simplifies the composition and fundamentally eliminates the problem of unevenness of the photoresist film caused by poor compatibility of different polarity components, which is conducive to forming a uniform and defect-free photoresist film layer.

[0037] (4) The lactone structural units introduced into the resin can effectively regulate the polarity and solubility of the polymer, producing a significant difference in solubility in alkaline developer, thereby improving the development contrast. At the same time, this structure also helps to improve the adhesion between the photoresist and the substrate, reduce pattern peeling or collapse, and ensure the formation of high-resolution patterns.

[0038] (5) The provided monomer and resin synthesis methods have clear steps, mild conditions, and readily available raw materials. They can be achieved through conventional organic synthesis and free radical polymerization, and have good process repeatability and large-scale production potential. Attached Figure Description

[0039] The foregoing contents, as well as other objects, features, and advantages of this disclosure, will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0040] Figure 1 A flowchart illustrating a method for preparing a photosensitive ArF resin monomer according to an embodiment of the present disclosure is provided.

[0041] Figure 2 The schematic diagram illustrates the photolithographic pattern of the photoresist according to Embodiment 1 of this disclosure under 193nm interference exposure conditions;

[0042] Figure 3 The schematic diagram illustrates the photolithographic pattern of the photoresist according to Embodiment 2 of this disclosure under 193nm interference exposure conditions; and

[0043] Figure 4 The schematic diagram illustrates the photolithographic pattern of the photoresist according to Embodiment 3 of this disclosure under 193nm interference exposure conditions. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0045] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0046] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0047] According to a first aspect of the present disclosure, a photosensitive ArF resin monomer is provided, the molecular structure of which is shown in Formula I:

[0048] Formula I

[0049] In this substituent, R1, R2, and R3 are independently selected from -H and -OH; R4, R5, R6, and R7 are independently selected from -H, -NO2, -CN, -CF3, -CHF2, -C2F5, -C4F9, -OH, halogen, C 1-12 Alkyl, C 1-12 Alkyl groups, -SO3H, -SO2C 1-12 -SO2N(C 1-12 Alkyl group 2, -SO2CF3, -CHO, -COC 1-12 Alkyl, -COOC 1-12 Alkyl, -CON(C) 1-12 Alkyl groups, -COOH, -B(OH)2, -B(OR)2, -C≡CH, -CH=CH-CN, and C 1-12 One of the haloalkyl groups.

[0050] The photosensitive ArF resin monomer provided in this embodiment introduces the o-nitrobenzyl cholic acid group with specific photoresponse characteristics as the core functional unit, which can undergo a highly efficient photolysis reaction at the ArF exposure wavelength. This allows the polarity conversion and solubility switching of the resin to be realized directly without relying on exogenous photoacid generators, effectively avoiding the problem of image quality degradation caused by uncontrollable acid diffusion in traditional chemical amplification mechanisms.

[0051] Furthermore, the rigid steroidal framework and optional aromatic ring structure contained in this monomer structure synergistically endow the polymer resin prepared from it with excellent plasma etching resistance. The rigid framework can effectively improve the glass transition temperature and structural density of the polymer, thus exhibiting higher stability and durability as a mask material in subsequent dry or wet etching processes, overcoming the shortcomings of insufficient etching resistance of traditional acrylate resins.

[0052] Furthermore, the photochemical properties, solubility, and free radical polymerization activity of the monomer can be precisely controlled through the diverse design and selection of R1 to R7 substituents in the Formula I resin monomer. For example, introducing electron-withdrawing groups can optimize its light absorption efficiency near 193 nm wavelength; adjusting the alkyl chain length or introducing polar functional groups can improve its solubility and film uniformity in conventional photoresist solvents; and combinations of different substituents can help balance the photosensitivity and development contrast of the resin. This structural tunability provides ample molecular design flexibility for developing high-performance photoresists suitable for different process windows.

[0053] In summary, the resin monomer provided in this disclosure integrates a photosensitive response unit, an etch-resistant rigid framework, and tunable functional substituents, laying a key molecular foundation for constructing an advanced ArF photoresist resin that combines non-chemical amplification characteristics, high etch resistance, excellent film-forming properties, and development performance.

[0054] Figure 1 A method for preparing a photosensitive ArF resin monomer according to an embodiment of the present disclosure is illustrated.

[0055] like Figure 1 As shown, the preparation method of the photosensitive ArF resin monomer according to the embodiments of this disclosure includes steps S1 to S3.

[0056] In step S1, cholic acid is reacted with an acyl chloride reagent in the presence of a first catalyst to obtain choyl chloride.

[0057] In the embodiments of this disclosure, step S1 may specifically include dissolving cholic acid in excess thionyl chloride (SOCl2), adding a small amount of N,N-dimethylformamide (DMF) dropwise under nitrogen protection, and heating under reflux in an oil bath at 75°C for 1-2 h until no gas is released. After the reaction is complete, the excess thionyl chloride is completely removed by vacuum distillation using a rotary evaporator to obtain solid choyl chloride. This step provides a key intermediate for subsequent esterification steps by converting the carboxylic acid group into a highly reactive acyl chloride. Using thionyl chloride as the acyl chloride reagent results in high reactivity, easy volatilization and removal of byproducts, and the catalytic effect of DMF can significantly improve reaction efficiency and selectivity. Vacuum distillation to remove excess reagent is a simple and efficient operation, which helps to obtain high-purity solid choyl chloride and lays the foundation for the smooth progress of subsequent steps.

[0058] In step S2, choyl chloride and o-nitrobenzyl alcohol are esterified in a first organic solvent in the presence of a first organic base to obtain o-nitrobenzyl cholate.

[0059] In the embodiments of this disclosure, step S2 may specifically include: dissolving choyl chloride in anhydrous dichloromethane (MC) under ice-water bath conditions; slowly adding an MC solution containing o-nitrobenzyl alcohol and anhydrous pyridine with stirring; after the addition is complete, raising the temperature to room temperature and continuing stirring for 8 hours; after the reaction is complete, drying the organic layer with anhydrous sodium sulfate, filtering, and then eluting with a gradient of petroleum ether and ethyl acetate to collect the target component; and rotary evaporating under reduced pressure to obtain a white product, which is o-nitrobenzyl cholate. This step involves the formation of an ester bond through the condensation of acyl chloride and alcohol, while simultaneously introducing a photosensitive o-nitrobenzyl structure into the molecule. The strategy of low-temperature addition and gradual temperature increase effectively controls the exothermic reaction and reduces side reactions. Subsequent gradient elution purification effectively separates unreacted raw materials and byproducts, obtaining a high-purity white solid product, providing a structurally well-defined and stable precursor for the final synthesis of the photosensitive monomer.

[0060] The reaction equations for steps S1 and S2 are as follows:

[0061]

[0062] In step S3, in the presence of a second catalyst and a second organic base, o-nitrobenzyl cholate and methacryloyl chloride are subjected to an esterification reaction in a second organic solvent to obtain o-nitrobenzyl cholate of methacrylate as shown in Formula I.

[0063] In the embodiments of this disclosure, step S3 may specifically include dissolving a certain amount of tert-butyl cholate obtained in (1) and a catalytic amount of 4-dimethylaminopyridine (DMAP) in anhydrous dichloromethane, and then slowly adding pyridine and methacrylamide chloride sequentially to the reaction system under a nitrogen atmosphere and an ice bath (0-5°C). After the addition is complete, the reaction mixture is allowed to naturally heat to room temperature, and the reaction is continuously stirred at this temperature for 8-20 h. The reaction formula for step S3 is as follows:

[0064]

[0065] This reaction introduces a methacryloyl group onto the cholic acid backbone, endowing the monomer with a polymerizable olefin bond, enabling it to embed into the resin backbone via free radical polymerization. Low-temperature reaction conditions inhibit the self-polymerization or degradation of the olefin bond, ensuring the integrity of the functional groups. Long-term reaction and post-treatment ensure complete reaction and product purification, ultimately yielding a structurally intact, photosensitizing, and polymerizable key monomer.

[0066] According to another aspect of the present disclosure, a method for preparing a photosensitive ArF photoresist resin is provided, comprising: dissolving a photosensitive ArF resin monomer, an adamantane (meth)acrylate monomer, a lactone (meth)acrylate monomer, and a free radical initiator in an organic solvent under an inert atmosphere, and carrying out a polymerization reaction at 60-70°C for 20-28 hours; after the reaction is completed, dropping the reaction solution into an antisolvent to precipitate a solid precipitate, collecting the precipitate and repeating the dissolution and precipitation process multiple times, and finally drying to obtain the photosensitive ArF photoresist resin.

[0067] For example, under nitrogen conditions, a mixture of all monomers and azobisisobutyronitrile (AIBN) was loaded into tetrahydrofuran (THF) and heated in an oil bath at 65°C for 24 h with stirring. The reaction is as follows:

[0068]

[0069] The ArF photoresist resin obtained by this preparation method is a terpolymer composed of the above-mentioned photosensitive ArF resin monomer, adamantane (meth)acrylate monomer, and lactone (meth)acrylate monomer. The molecular structure of the ArF photoresist resin is shown in Formula II:

[0070] Formula II

[0071] In this substituent, R1, R2, and R3 are independently selected from -H and -OH; R4, R5, R6, and R7 are independently selected from -H, -NO2, -CN, -CF3, -CHF2, -C2F5, -C4F9, -OH, halogen, C 1-12 Alkyl, C 1-12 Alkyl groups, -SO3H, -SO2C 1-12 -SO2N(C 1-12 Alkyl group 2, -SO2CF3, -CHO, -COC 1-12 Alkyl, -COOC 1-12 Alkyl, -CON(C) 1-12 Alkyl groups, -COOH, -B(OH)2, -B(OR)2, -C≡CH, -CH=CH-CN, and C 1-12 One of the haloalkyl groups; R8 is a substituent on the adamantyl alkyl group, n represents the number of R8 substituents, and the n R8 substituents are independently selected from hydrogen, amino, and di(C) alkyl groups. 1-12 Alkyl)amino, C 1-12 Alkylamino, cyano, isocyanate, isothiocyanate, carboxyl, C 1-15 Alkoxycarbonyl, hydroxyl, halogen, C 1-12 Alkylamino, amide, azide, mercapto, acyl halide, C 1-12 Alkyl, C1-12 an alkoxy group, C 1-12 a haloalkyl group, C 3-20 a cycloalkyl group, C 1-12 an alkylcarbonyl group, and C 6-20 one of an arylcarbonyl group, where n is a positive integer and 1 ≤ n ≤ 5; and A is a lactone structural unit.

[0072] In an embodiment of the present disclosure, in Formula II, x, y, and z respectively represent the molar mass percentages of the corresponding monomers, where 0 < x ≤ 8 %, 0 < y ≤ 80%, and 20% ≤ z ≤ 40%, and x + y + z = 100%.

[0073] In an embodiment of the present disclosure, the lactone structural unit is selected from one of the structures shown in Formula III, Formula IV, and Formula V.

[0074] Formula III

[0075] Formula IV

[0076] Formula V

[0077] where * is the connection site; Ra, Rb, Rc, Rd, Re, Rf, Rg, Rh, and Ri are each independently selected from hydrogen, an amino group, bis(C<00000,60>alkyl)amino group, C 1-12 alkylamino group, cyano group, isocyanate group, isothiocyanate group, carboxyl group, hydroxyl group, halogen, C 1-12 alkylamino group, amide group, azide group, mercapto group, acyl halide group, C 1-12 alkyl group, C 1-12 alkoxy group, C 1-12 haloalkyl group, and C 1-12 one of an alkylcarbonyl group.

[0078] According to the ArF photoresist resin provided by the embodiments of the present disclosure, through innovative copolymer structure design, the synergistic unity of a non-chemically amplified photosensitive mechanism and high etching resistance has been successfully achieved, and at the same time, it has excellent development contrast, substrate adhesion, and high structural tunability, thereby systematically solving multiple technical bottlenecks faced by traditional photoresist materials in advanced processes.

[0079] Specifically, the resin structure contains photosensitive monomer units in a specific molar ratio. The o-nitrobenzyl ester cholic acid groups modified with these units undergo efficient photolysis at a 193nm ArF exposure wavelength, directly generating carboxylic acid groups. This drives a polarity transition of the resin in the exposure area from hydrophobic to hydrophilic. This process is entirely based on the resin's own photochemical reaction, eliminating the need for exogenous photoacid-generating agents. Therefore, it fundamentally avoids the defects in traditional chemically amplified photoresists caused by uncontrollable acid diffusion, such as increased linewidth roughness, critical dimension deviations, and pattern bridging, significantly improving the accuracy and process stability of pattern transfer. Simultaneously, the adamantane structural units introduced into the resin, through their unique cage-like three-dimensional rigid framework and high C / H ratio, effectively enhance the overall structural density, thermal stability, and intermolecular chain interactions of the polymer. This allows it to significantly resist physical sputtering and chemical etching in subsequent plasma dry etching environments, thus meeting the stringent requirements for mask material corrosion resistance in advanced processes at 14nm and below.

[0080] Furthermore, by introducing lactone structural units, this resin achieves synergistic optimization of development contrast and substrate adhesion. The polarity of the lactone ring itself and its ring strain structure enable it to exhibit controllable dissolution behavior in alkaline developer, creating a significant difference in dissolution rate between exposed and unexposed areas, thereby achieving high development contrast and laying the foundation for forming high-resolution patterns with steep sidewalls. In addition, the carbonyl and other polar functional groups in the lactone unit can form van der Waals forces or hydrogen bonds with the substrate surface, effectively enhancing the interfacial adhesion between the photoresist film layer and the substrate, preventing pattern peeling or collapse during processing, and ensuring the integrity of the pattern structure. The structure of the lactone unit can be selected from Formula II, Formula III, or Formula IV, and the substituents (Ra to Ri) have a diverse selection space. Through structural adjustment, the resin polarity, spatial configuration, and stability can be finely controlled, thereby adapting to different development conditions and substrate materials.

[0081] Furthermore, this resin system employs a modular design, possessing high structural flexibility and performance tunability. By adjusting the molar ratio of photosensitive monomers, adamantane monomers, and lactone monomers, the resin's photosensitivity, etching resistance, and development performance can be systematically balanced to meet the requirements of different photolithography processes. The adamantane unit can bear 1 to 5 substituents R, encompassing hydrogen, alkyl, halogen, polar, and reactive groups, allowing for the adjustment of the resin's hydrophilicity / hydrophobicity, polarity, and interfacial compatibility while maintaining a rigid framework. The lactone unit also supports various substituent modifications, further expanding the resin's functional adaptability. For example, introducing fluorine-containing groups can adjust the surface energy for immersion lithography, while introducing crosslinkable groups can enhance the resin's mechanical strength and solvent resistance. Therefore, this resin system constitutes a widely tunable material platform, enabling the development of a series of products suitable for ArF dry lithography, immersion lithography, and other advanced patterning processes through directional adjustments to the molecular structure.

[0082] In summary, this disclosure integrates the photosensitive response unit, the etching resistance enhancement unit, and the development control unit into the same copolymer chain, achieving an organic combination of multiple key properties. This provides an effective material solution for the development of high-performance ArF photoresists and has significant industrial application value.

[0083] Based on the above-mentioned photosensitive ArF photoresist resin, this disclosure also provides a photoresist composition comprising: the above-mentioned photosensitive ArF photoresist resin; and an organic solvent; wherein, based on the total mass of the photoresist composition, the mass percentage of the photosensitive ArF photoresist resin is 4% to 6%.

[0084] Optionally, the organic solvent is selected from one or a mixture of two of propylene glycol methyl ether acetate, propylene glycol methyl ether, ethyl lactate, butyl acetate, and cyclohexanone. The resin content design of this photosensitive ArF photoresist ensures that the composition has suitable viscosity and rheological properties, thereby forming a uniform, defect-free, and thickness-controllable film during spin coating. The solvent, as a carrier, directly affects the resin's solubility, film quality, and subsequent drying behavior. By controlling the resin content within this range, sufficient photosensitive unit density is ensured for effective exposure response, while problems such as increased viscosity, uneven coating, or increased film stress due to excessive solid content are avoided, providing a stable and reliable film foundation for subsequent photolithography processes.

[0085] In some exemplary embodiments, the photoresist composition further includes a leveling agent; the leveling agent is selected from fluorinated polyester-based or polyether-modified siloxane-based leveling agents; and the mass percentage of the leveling agent is 0.01% to 0.02% based on the total mass of the photoresist composition. Fluorinated polyester-based or polyether-modified siloxane-based leveling agents can effectively reduce the surface tension of the composition, promote its uniform spreading on the substrate surface, and reduce film defects such as "orange peel" and pinholes caused by uneven wetting or differences in solvent evaporation. Strictly controlling the amount of leveling agent added within the low range of 0.01% to 0.02% is sufficient to exert its effect on improving film quality, while avoiding compatibility problems, development residues, or interference with photolithography performance that may be caused by excessive addition. This trace addition strategy maintains the main properties of the resin system to the greatest extent possible without affecting the uniformity and flatness of the film.

[0086] The photoresist composition according to embodiments of this disclosure can be used for 193nm interference lithography, 365nm interference lithography, 193nm projection lithography, 248nm projection lithography, 365nm projection lithography, 193nm SP lithography, 248nm SP lithography, 365nm SP lithography, or 193nm immersion lithography.

[0087] Example 1:

[0088] In this embodiment, the photosensitive ArF photoresist resin is a polymethyl methacrylate resin derivative containing 3-hydroxyadamantane, γ-butyrolactone, and o-nitrobenzyl cholate, with the molecular formula:

[0089]

[0090] The synthesis method of polymethyl methacrylate resin derivatives containing the structures of 3-hydroxyadamantane, γ-butyrolactone, and o-nitrobenzyl cholic acid is as follows: In a 250 mL three-necked flask equipped with a magnetic stirrer, thermometer, constant-pressure dropping funnel, and tail gas absorption device, 4.08 g of cholic acid and 10 mL of SOCl2 were added. Under nitrogen and an ice-water bath (0-5℃), 1-2 drops of DMF were added dropwise. After the addition was complete, the ice bath was removed, and the reaction mixture was heated to reflux (~75℃) and stirred continuously at this temperature until no more gas was released. After the reaction was completed, excess thionyl chloride was removed by rotary evaporation under reduced pressure in a 38℃ water bath to obtain a white solid crude choyl chloride product. The obtained choyl chloride was dissolved in 30 mL of anhydrous dichloromethane, and the solution was cooled to 0-5℃ in an ice-water bath. Under nitrogen protection, 15 mL of anhydrous dichloromethane solution containing 1.67 g o-nitrobenzyl alcohol and 1.6 mL anhydrous pyridine was slowly added dropwise to the cooled solution, controlling the dropping rate (maintaining the reaction system temperature below 10 °C). After the addition was complete, the reaction mixture was allowed to warm naturally to room temperature, and the reaction was continued at room temperature for 6–8 h. The reaction progress was monitored by thin-layer chromatography (TLC) until the choyl chloride starting material spot essentially disappeared.

[0091] After the reaction was complete, the reaction mixture was transferred to a separatory funnel and the organic phase was washed with 30 mL of dilute hydrochloric acid (to remove excess pyridine). The organic phase was separated, and the remaining aqueous phase was extracted twice with 15 mL of dichloromethane. All organic phases were combined and washed successively with 30 mL of saturated sodium bicarbonate solution and 30 mL of saturated brine. After drying with anhydrous sodium sulfate and filtering, the solution was concentrated under reduced pressure to obtain a pale yellow crude product. The crude product was subjected to gradient elution using a mobile phase of petroleum ether:ethyl acetate (volume ratio 10⁻³:1). The fraction containing the target product was collected, and the solvent was removed by evaporation under reduced pressure to obtain high-purity o-nitrobenzyl cholic acid.

[0092] The product and a catalytic amount of 4-dimethylaminopyridine (DMAP) were dissolved in anhydrous dichloromethane. Under nitrogen atmosphere and an ice bath (0-5°C), 4.88 mL of pyridine and 3.32 mL of methacryloyl chloride were slowly added sequentially to the reaction system. After the addition was complete, the ice bath was removed, and the reaction mixture was allowed to warm naturally to room temperature, where it was stirred continuously for 8-20 h. After the reaction was complete, 50 mL of deionized water was added to quench the reaction mixture, and the organic phase was separated. The aqueous phase was extracted with 60 mL of dichloromethane. The organic phases were combined and washed sequentially with 50 mL of dilute hydrochloric acid solution, 50 mL of saturated sodium bicarbonate solution, and 50 mL of saturated brine. The resulting organic layer was dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure to remove the solvent, yielding the crude product. The crude product was purified by silica gel column chromatography using a gradient elution of petroleum ether:ethyl acetate (v / v 15-8:1), and the concentrate was concentrated to give a white solid.

[0093] Under a nitrogen atmosphere, 5.78 g of 3-hydroxy-1-adamantane methacrylate, 5.55 g of 2-oxotetrahydrofuran-3-ylmethacrylate, 20.04 g of o-nitrobenzylcholine methacrylate, and 2.76 g of AIBN were dissolved in 500 mL of THF. The reaction apparatus was placed in a 65°C oil bath and reacted for 24 h, resulting in a pale yellow solution. After the reaction was complete, the solution was cooled to room temperature. The reaction liquid was precipitated in petroleum ether, filtered to obtain a solid, and washed three times with petroleum ether to remove inorganic salts. The solid was dissolved in toluene and precipitated three times in petroleum ether. The resulting solid was then dissolved in ethyl acetate and precipitated three times in petroleum ether. The solid was dried to obtain a white powder. NMR calculations showed that the grafting rate of o-nitrobenzylcholine methacrylate was 26.7%.

[0094] Example 2:

[0095] In this embodiment, the photosensitive ArF photoresist resin is a polymethyl methacrylate resin derivative containing 3,5-dihydroxyadamantane, γ-caprolactone, and deoxycholic acid-5-fluoro-2-nitrobenzyl ester structures, with the molecular formula:

[0096]

[0097] The synthesis method of this embodiment is the same as that of Example 1. The obtained white solid was dried, and the grafting rate of o-nitrobenzyl cholate was calculated to be 34.6% by NMR.

[0098] Example 3:

[0099] In this embodiment, the photosensitive ArF photoresist resin is a derivative containing the structures of N-methyl-1-adamantaneamine, 6-cyano-γ-caprolactone, and 2,4-dinitro-5-(trifluoromethyl)benzyl ester of deoxycholic acid, with the molecular formula:

[0100]

[0101] The synthesis method of this embodiment is the same as that of Example 1. The obtained white solid was dried, and the grafting rate of o-nitrobenzyl cholate was calculated to be 22.3% by NMR.

[0102] Example 4:

[0103] For the preparation of the photoresist film, the materials obtained in Examples 1-3 were dissolved in cyclohexanone to prepare a solution of 33 mg / mL. After complete dissolution, the solution was filtered through a filter membrane with a pore size of 0.22 μm, and then spin-coated onto a silicon wafer. The film was baked at 100°C for 2 min, and the film formation and uniformity were good. The film thickness was measured using an ellipsometry and was approximately 100~150 nm.

[0104] Example 5:

[0105] The materials synthesized in Examples 1-3 were used to prepare thin films on silicon wafers using the method in Example 4. The films were developed using a 2.38% tetramethylammonium hydroxide solution for 30 seconds, followed by fixing with deionized water for 15 seconds. The film thickness before and after development was measured using an ellipsometry, and the film retention rate was calculated based on the film thickness. The results are shown in Table 1.

[0106] Table 1. Results of photoresist retention rate test

[0107]

[0108] As shown in Table 1, the photoresist films prepared in Examples 1 to 3 all exhibited 100% film retention rate after development in the unexposed areas using a 2.38% tetramethylammonium hydroxide solution. This result not only demonstrates that the photoresist resin has excellent alkali resistance in the unexposed state (excellent dissolution inhibition in the unexposed area), but also highlights the system's extremely high dissolution contrast when combined with the characteristic that the exposed areas can be completely removed, providing a foundation for obtaining a clear, residue-free positive photolithographic pattern. Furthermore, the three examples with different monomer structures and ratios all maintained a 100% film retention rate, indicating that the resin design has a wide process window and good reliability, and is not sensitive to monomer replacement and ratio adjustments.

[0109] Example 6: Sensitivity Test

[0110] The materials synthesized in Examples 1-3 were dissolved in cyclohexanone to prepare solutions of 33 mg / mL. After complete dissolution, the solutions were filtered through a 0.22 μm pore size filter membrane. The solutions were then spin-coated onto a silicon wafer, baked at 100°C for 2 min, and subjected to interference exposure at a wavelength of 193 nm (exposure area: approximately 0.01 cm²). 2 The circle was then baked at 100°C for 1 minute. Developed with a 2.38% tetramethylammonium hydroxide solution for 30 seconds, and then fixed with deionized water for 15 seconds.

[0111] The thickness difference between the exposed and unexposed areas was measured using a step meter. The exposure dose when the thickness difference was equal to the film thickness was defined as the sensitivity, as shown in Table 2.

[0112] Table 2. Results of Photoresist Sensitivity Test

[0113]

[0114] As shown in Table 2, the sensitivities of the photoresists prepared in Examples 1 to 3 are 400 mJ / cm², respectively. 2 360 mJ / cm 2 and 540 mJ / cm 2This data shows that the photosensitivity of the photoresist can be effectively controlled by adjusting the structure and ratio of different functional monomers in the copolymer. All examples exhibit a usable sensitivity range, indicating that the photosensitive resin system designed in this invention has good process applicability and controllability, and can meet the photolithography requirements under different exposure dose conditions.

[0115] Example 7: Resolution Test

[0116] The materials synthesized in Examples 1-3 were dissolved in cyclohexanone to prepare solutions of 33 mg / mL. After complete dissolution, the solutions were filtered through a 0.22 μm pore size filter membrane. The solutions were spin-coated onto silicon wafers coated with an organic bottom antireflective coating (BARC) (baked at 240°C for 10 min). After baking at 100°C for 2 min, 193 nm interference exposure was performed, followed by baking at 100°C for 1 min. Development was performed using a 2.38% tetramethylammonium hydroxide solution for 30 s, followed by fixing with deionized water for 15 s. After drying, the images were examined using a scanning electron microscope, yielding a resolution image with a linewidth:slit width ratio of 1:1. Figures 2-4 As shown.

[0117] Depend on Figures 2-4 It can be seen that the photosensitive ArF photoresist resins prepared in Examples 1-3 all successfully achieved high-resolution patterns with a period of 300 nm and a linewidth to slit width ratio of 1:1. The edges of each pattern are clear, the sidewalls are steep, and the pattern uniformity is good, with no obvious defects or bridging. This result proves that the photoresist resin provided by this invention, copolymerized from o-nitrobenzyl (meth)acrylate, adamantane (meth)acrylate, and lactone (meth)acrylate monomers, possesses excellent photolithographic performance under 193 nm interference exposure conditions, meeting the stringent requirements for pattern fidelity in high-precision photolithography processes. The pattern quality of different examples is uniform and stable, further verifying the reliability of the resin composition and ratio, and the breadth of the process window.

[0118] Those skilled in the art will understand that the features described in the various embodiments of this disclosure can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. In particular, the features described in the various embodiments of this disclosure can be combined and / or combined in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or combinations fall within the scope of this disclosure.

Claims

1. A photosensitive ArF resin monomer, characterized in that, The molecular structure of the resin monomer is shown in Formula I: Formula I wherein, the substituents R1, R2, and R3 are each independently selected from one of -H and -OH; The substituents R4, R5, R6, and R7 are independently selected from -H, -NO2, -CN, -CF3, -CHF2, -C2F5, -C4F9, -OH, halogens, and C. 1-12 Alkyl, C 1-12 Alkyl group, -SO3H, -SO2C 1-12 -SO2N(C 1-12 Alkyl group 2, -SO2CF3, -CHO, -COC 1-12 Alkyl, -COOC 1-12 Alkyl, -CON(C) 1-12 Alkyl groups, -COOH, -B(OH)2, -B(OR)2, -C≡CH, -CH=CH-CN, and C 1-12 One of the haloalkyl groups.

2. A method for preparing the photosensitive ArF resin monomer as described in claim 1, characterized in that, comprising: Step S1, reacting cholic acid with an acyl chlorinating reagent in the presence of a first catalyst to obtain cholyl chloride; Step S2, in the presence of a first organic base, carrying out an esterification reaction between the cholyl chloride and o-nitrobenzyl alcohol in a first organic solvent to obtain o-nitrobenzyl cholate; Step S3, in the presence of a second catalyst and a second organic base, carrying out an esterification reaction between the o-nitrobenzyl cholate and methacryloyl chloride in a second organic solvent to obtain o-nitrobenzyl methacrylate cholate shown in Formula I.

3. The preparation method according to claim 2, characterized in that, In Step S1, the acyl chlorinating reagent is thionyl chloride, and the first catalyst is N,N-dimethylformamide; In Step S2, the first organic base is pyridine, and the first organic solvent is dichloromethane; In Step S3, the second catalyst is 4-dimethylaminopyridine, the second organic base is pyridine, and the second organic solvent is dichloromethane.

4. A method for preparing a photosensitive ArF photoresist resin, characterized in that, comprising: Under an inert atmosphere, dissolving the photosensitive ArF resin monomer, adamantane (meth)acrylate monomer, lactone (meth)acrylate monomer as claimed in claim 1 and a radical initiator in an organic solvent, and carrying out a polymerization reaction at 60-70 °C for 20-28 hours; After the reaction is completed, dropping the reaction solution into an anti-solvent to precipitate a solid, collecting the precipitate and then carrying out multiple dissolutions and precipitations, and finally drying to obtain the photosensitive ArF photoresist resin.

5. A photosensitive ArF photoresist resin prepared according to the preparation method of claim 4, characterized in that, The ArF photoresist resin is a terpolymer copolymerized from the photosensitive ArF resin monomer, adamantane (meth)acrylate monomer and lactone (meth)acrylate monomer as claimed in claim 1, and the molecular structure of the ArF photoresist resin is shown in Formula II: Formula II wherein, the substituents R1, R2, and R3 are each independently selected from one of -H and -OH; The substituents R4, R5, R6, and R7 are independently selected from -H, -NO2, -CN, -CF3, -CHF2, -C2F5, -C4F9, -OH, halogens, and C. 1-12 Alkyl, C 1-12 Alkyl group, -SO3H, -SO2C 1-12 -SO2N(C 1-12 Alkyl group 2, -SO2CF3, -CHO, -COC 1-12 Alkyl, -COOC 1-12 Alkyl, -CON(C) 1-12 Alkyl groups, -COOH, -B(OH)2, -B(OR)2, -C≡CH, -CH=CH-CN, and C 1-12 One of the haloalkyl groups; R8 represents a substituent on the adamantyl alkyl group, and n represents the number of R8 substituents. These n R8 substituents are independently selected from hydrogen, amino, and di(C) groups. 1-12 Alkyl)amino, C 1-12 Alkylamino, cyano, isocyanate, isothiocyanate, carboxyl, C 1-15 Alkoxycarbonyl, hydroxyl, halogen, C 1-12 Alkylamino, amide, azide, mercapto, acyl halide, C 1-12 Alkyl, C 1-12 Alkoxy, C 1-12 Haloalkyl, C 3-20 cycloalkyl, C 1-12 alkyl carbonyl and C 6-20 One of the aryl carbonyl groups, where n is a positive integer and 1 ≤ n ≤ 5; and A is a lactone structural unit.

6. The photosensitive ArF photoresist resin according to claim 5, characterized in that, 7. The photosensitive ArF photoresist resin according to claim 5 or 6, characterized in that, In Formula II, x, y, and z respectively represent the molar mass percentages of the corresponding monomers, wherein, 0 < x ≤ 80%, 0 < y ≤ 80% and 20% ≤ z ≤ 40%, and x + y + z = 100%. Formula III Formula IV Formula V The lactone structural unit is selected from one of the structures shown in Formula III, Formula IV, and Formula V, Ra, Rb, Rc, Rd, Re, Rf, Rg, Rh, and Ri are independently selected from hydrogen, amino, and di(C) groups. 1-12 Alkyl)amino, C 1-12 Alkylamino, cyano, isocyanate, isothiocyanate, carboxyl, hydroxyl, halogen, C 1-12 Alkylamino, amide, azide, mercapto, acyl halide, C 1-12 Alkyl, C 1-12 Alkoxy, C 1-12 Halogenated alkyl groups and C 1-12 One of the alkyl carbonyl groups.

8. The photosensitive ArF photoresist resin according to claim 5 or 6, characterized in that, wherein, * is the connection site; ； ； 。 9. A photoresist composition, characterized in that, The structure of the photosensitive ArF photoresist resin is selected from any one of the following structural formulas: comprising: The photosensitive ArF photoresist resin as claimed in any one of claims 5 to 8; and an organic solvent; 10. The photoresist composition according to claim 9, characterized in that, wherein, based on the total mass of the photoresist composition, the mass percentage of the photosensitive ArF photoresist resin is 4% to 6%. The photoresist composition further comprises a leveling agent; The leveling agent is selected from a fluorinated polyester type or a polyether-modified silicone type leveling agent; and based on the total mass of the photoresist composition, the mass percentage of the leveling agent is 0.01% to 0.02%.

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