High-strength extreme ultraviolet photoresist and preparation method and application thereof

Abstract

The application relates to the field of extreme ultraviolet photoresists, and specifically discloses a high-strength extreme ultraviolet photoresist and a preparation method and application thereof. The film-forming resin of the extreme ultraviolet photoresist is an ethylene oxide-caprolactam block copolymer, and the structural general formula of the ethylene oxide-caprolactam block copolymer is (EO)x-(CL)y. The ethylene oxide (EO) and caprolactam (CL) are block copolymerized to form a new photoresist film-forming resin which has the high strength of polyamide and the flexible and hydrophilic characteristics of ethylene oxide. The CL segment can provide high Tg and excellent etching resistance, has strong hygrothermal dimensional stability, and enables the photoresist film to maintain the integrity of a pattern in high-temperature etching; the EO segment endows the photoresist film with a hydrophilic channel, accelerates the penetration of a developing solution, improves the dissolution contrast, and reduces developing expansion; and the two segments are synergistic, and can break through the "three-point contradiction" of sensitivity-resolution-thermal stability of the existing system.

Description

Technical Field

[0001] This application relates to the field of extreme ultraviolet (EUV) photoresists, and more specifically, to a high-strength EUV photoresist using ethylene oxide-caprolactam block copolymer as the film-forming resin, its preparation method, and its application. Background Technology

[0002] With the rapid development of semiconductor technology, semiconductor processes are constantly moving towards smaller nodes, placing extremely high demands on patterning technology in semiconductor manufacturing. Extreme ultraviolet (EUV) lithography, with its unique advantages such as short wavelength and high resolution, has become the only core patterning technology in current semiconductor manufacturing capable of mass production. Its emergence has greatly propelled the semiconductor industry towards higher integration and smaller size, enabling chips to accommodate more transistors, thereby improving chip performance and functionality. For EUV photoresist, its performance directly affects the manufacturing quality and performance of semiconductor devices, requiring high sensitivity (≤30mJ / cm). 2 High resolution (≤18nm), low linewidth roughness (LWR≤2.5nm), excellent etching selectivity, and a good process window are all key performance requirements that must be met simultaneously.

[0003] In existing technologies, various systems and methods are conventionally employed to meet the performance requirements of extreme ultraviolet (EUV) photoresists. Among these, polyacrylate systems (such as PMMA derivatives) are relatively common. Through specific polymer structures and chemical properties, they achieve a certain level of basic photoresist performance and resolution. Phenolic resin-sulfonate systems (such as ESCAP) utilize a combination of phenolic resin and sulfonate to achieve moderate sensitivity, playing a role in the photolithography process. Polyhydroxystyrene (PHS) systems, with their tunable polarity, are also widely used in the photoresist field, allowing for adjustments to polarity to meet different photolithography needs.

[0004] However, existing mainstream photoresist systems have significant drawbacks. Polyacrylate systems suffer from low sensitivity, poor etching resistance, and a low glass transition temperature (Tg≈110℃), making them unsuitable for subsequent high-temperature processing, thus limiting their application in advanced semiconductor manufacturing. Phenolic resin-sulfonate systems exhibit extremely high polarity, leading to severe swelling during development and resulting in increased linewidth roughness (LWR>3nm). Furthermore, their glass transition temperature decreases significantly after aging in a high-temperature, high-humidity environment (85℃ / 85%RH), indicating that their thermomechanical stability still needs improvement. Polyhydroxystyrene exhibits excessive absorption of EUV photons at 13.5nm (μ>0.5μm). -1 This can easily lead to bubble formation and pattern collapse, and the system also has a high residual metal ion content (Na).+ A concentration greater than 50 ppb can adversely affect the reliability of the device. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides a high-strength extreme ultraviolet photoresist, its preparation method and application, and electronic devices.

[0006] Firstly, this application provides a high-strength extreme ultraviolet photoresist, which employs the following technical solution:

[0007] A high-strength extreme ultraviolet (EUV) photoresist, wherein the film-forming resin of the EUV photoresist is an ethylene oxide-caprolactam block copolymer, and the general structural formula of the ethylene oxide-caprolactam block copolymer is:

[0008] (EO)x-(CL)y;

[0009] Wherein, EO is ethylene oxide, CL is caprolactam, x=70-75mol%, y=25-30mol%, and its number-average molecular weight Mn=7800-10000g / mol, and molecular weight distribution Đ≤1.20.

[0010] Preferably, the glass transition temperature Tg of the ethylene oxide-caprolactam block copolymer is ≥175℃, and E′@180℃ is ≥3.2GPa.

[0011] By adopting the above technical solution, this application uses block copolymerization of ethylene oxide (EO) and caprolactam (CL) to form a novel photoresist film-forming resin, abbreviated as EOCL, which combines the high strength of polyamide with the flexible and hydrophilic properties of ethylene oxide. The CL segment of this application provides high Tg and excellent etching resistance, and has strong dimensional stability under humid heat, enabling the film to maintain the integrity of the pattern during high-temperature etching; the EO segment provides hydrophilic channels, accelerates the penetration of the developer, improves the dissolution contrast, and reduces the development swelling; the synergy of the two is expected to overcome the "triangular contradiction" of sensitivity-resolution-thermal stability in the existing system.

[0012] Preferably, the ethylene oxide-caprolactam block copolymer is prepared by the following method:

[0013] S1. Under anhydrous and oxygen-free conditions and a temperature of -30~-10℃, caprolactam is subjected to ring-opening polymerization under the action of an initiator to obtain CL block;

[0014] S2. Add ethylene oxide to the system in step S1, and then carry out a polymerization reaction at a temperature of -10~10℃ to obtain CL-EO diblock;

[0015] S3. Add methanol to the system in step S2 to terminate the reaction, then precipitate, filter, and vacuum dry to obtain ethylene oxide-caprolactam block copolymer.

[0016] In the technical solution of this application, the total reaction time of S1 and S2 is ≤5h, and the monomer conversion rate is ≥97%. This application achieves a high conversion rate in a short reaction time, and can be directly used for photoresist formulation without additional purification, significantly reducing production costs and cycle time.

[0017] In the technical solution of this application, the initiator is potassium bis(trimethylsilyl)amino (KHMDS), and its dosage is 1.0-1.2% of the total monomer mass. Using this initiator at this dosage can ensure that the polymerization rate and molecular weight distribution are controllable, and further enable the obtained copolymer to have a number average molecular weight of Mn=8000-8300g / mol and a molecular weight distribution K≤1.17, which meets the requirements of photoresist film-forming resin.

[0018] In the technical solution of this application, the polymerization reaction is carried out in a 316L stainless steel reactor. The inner wall of the reactor is electrolytically polished to reduce Ra≤0.15μm, thereby reducing metal leaching and resin adhesion to the wall.

[0019] By adopting the above technical solution, the "anionic ring-opening-sequential feeding" one-pot method for preparing EOCL in this application can precisely control the uniformity of the block structure, so that the total metal ion content of the prepared EOCL is ≤4ppb (far lower than 15ppb of non-sequential feeding), sodium ion content is ≤2ppb, and iron ion content is ≤1ppb, which can be directly used for compounding; and the acid value is ≤0.04mgKOH / g, and the moisture content is ≤400ppm, which can effectively avoid the occurrence of acid-catalyzed side reactions and bubble defects during the compounding process.

[0020] If non-sequential feeding is used, i.e., EO and CL monomers are added simultaneously, the molecular weight distribution of the copolymer will become wider (in one specific embodiment, the molecular weight distribution K increased from 1.16 to 1.42) and the Tg will decrease (in one specific embodiment, the Tg decreased from 177°C to 168°C). Ultimately, this will reduce the sensitivity of the photoresist and increase the defect rate, making it unable to meet the requirements of the 2nm node process.

[0021] The EOCL of this application can be applied to the preparation of extreme ultraviolet photoresists, electron beam photoresists, or nanoimprint lithography. In particular, it meets the requirements of 2nm node semiconductor mass production for high-sensitivity, low-defect, and high-etch-resistant photoresists, and is suitable for FinFET, GAA-FET, DRAM capacitors, and photonic crystals.

[0022] Preferably, the raw materials used in the extreme ultraviolet photoresist, by weight percentage, include the following components:

[0023] 9-12% ethylene oxide-caprolactam block copolymer;

[0024] Photoacid-producing agent: 0.15-0.25%;

[0025] Crosslinking agent 0.10-0.15%;

[0026] Additives 0.01-0.02%;

[0027] Solvent balance.

[0028] In the technical solution of this application, the photoacid-generating agent is a sulfonium salt or an iodonium salt. Both have absorption peaks in the 190-250 nm range, are sensitive to 13.5 nm extreme ultraviolet radiation, and have a quantum acid-generating efficiency ≥0.85. Furthermore, this application uses triphenylsulfonium trifluoromethanesulfonate (TPS-TfO) as the photoacid-generating agent.

[0029] In the technical solution of this application, the crosslinking agent is a polyfunctional isocyanate or a polyfunctional epoxy resin. Further, this application uses tris(4-phenyl isocyanate)methane as the crosslinking agent.

[0030] In the technical solution of this application, the additives include leveling agents and antioxidants. Further, this application uses polyether siloxane (such as BYK-333) as a leveling agent and 2,6-di-tert-butyl-4-methylphenol as an antioxidant.

[0031] In the technical solution of this application, the solvent is γ-butyrolactone and / or propylene glycol methyl ether acetate, with a solid content of 10-15 wt%. Further, this application uses a mixture of γ-butyrolactone and propylene glycol methyl ether acetate as the solvent.

[0032] Preferably, the extreme ultraviolet photoresist has a linear absorption coefficient of μ=0.28-0.38 / μm at an extreme ultraviolet light wavelength of 13.5nm.

[0033] Preferably, after the extreme ultraviolet photoresist is formed and aged for 168 hours at 85℃ / 85%RH, the Tg decrease is ≤2℃, the development expansion rate is ≤3%, the line width roughness LWR after development is ≤2.2nm, and the local critical size uniformity LCDU is ≤1.8nm.

[0034] By adopting the above technical solution, this application uses EOCL as the core film-forming resin and, through the scientific combination of photoacid-generating agents, crosslinking agents, additives, and solvents, forms a photoresist system with synergistic performance. Its absorption of photons at the 13.5nm extreme ultraviolet wavelength is more reasonable, reducing bubble generation and pattern collapse problems, which helps to achieve high-resolution and high-sensitivity photolithography effects. Furthermore, it exhibits excellent thermal stability; after aging at 85℃ / 85%RH for 168 hours after film formation, the Tg decrease is ≤2℃. Simultaneously, it is less prone to swelling during development, resulting in lower linewidth roughness and better uniformity of local critical dimensions, ensuring the fineness and dimensional consistency of the photolithographic pattern.

[0035] Specifically, the film-forming resin not only dominates the film-forming performance of the photoresist, but its EO blocks also provide hydrophilic channels to ensure development contrast, while the CL blocks significantly improve the photoresist's etching resistance and glass transition temperature through rigid amide bonds. The photoacid generator produces a strong acid after exposure, catalyzing the ring-opening crosslinking of epoxy groups in the EOCL, achieving patterned curing and high-sensitivity response. The crosslinking agent enhances the crosslinking density of the resin, further improving the mechanical strength and etching selectivity of the cured photoresist. Additives optimize the surface smoothness of the film, inhibit oxidative degradation of the system, and improve the storage stability of the photoresist at 4°C. The solvent effectively dissolves the components and adjusts the viscosity of the photoresist, ensuring uniformity during spin coating.

[0036] Secondly, this application provides a method for preparing a high-strength extreme ultraviolet photoresist, which employs the following technical solution:

[0037] A method for preparing a high-strength extreme ultraviolet photoresist includes the following steps:

[0038] I. Raw material pretreatment;

[0039] II. Under the protection of an inert gas, the ethylene oxide-caprolactam block copolymer and solvent are mixed and stirred until the ethylene oxide-caprolactam block copolymer is completely dissolved. Then, the photoacid generator, crosslinking agent and additives are added and stirring is continued to form a uniform and transparent mixture.

[0040] III. Filter and degas to obtain high-strength extreme ultraviolet photoresist.

[0041] In the technical solution of this application, the raw material pretreatment specifically involves: drying EOCL in a vacuum drying oven at 75-85℃ for 3.5-4.5 hours to control the moisture content to ≤0.05%; purifying the photoacid-producing agent and crosslinking agent using a silica gel column to ensure a purity of ≥99.5%; and dehydrating the solvent using a molecular sieve to ensure a moisture content of ≤0.05%.

[0042] In the technical solution of this application, in step II, the mixture is stirred at 250-350 rpm for 1.5-2.5 hours at room temperature until EOCL is completely dissolved. After adding the photoacid-generating agent, crosslinking agent and additives, the mixture is stirred at room temperature and speed for another 3.5-4.5 hours until a uniform and transparent mixture is formed.

[0043] In the technical solution of this application, the filtration and degassing specifically involves: circulating the mixture obtained in step II through a 0.22μm nylon filter element multiple times to remove mechanical impurities in the system, so that subsequent vacuum degassing can eliminate microbubbles in the system without additional vacuum degassing.

[0044] By adopting the above technical solution, the extreme ultraviolet (EUV) photoresist prepared by the method of this application has a solid content of 9-12 wt%, a viscosity of 4.8-5.5 cp (25℃, shear rate 100 / s), a surface tension of 25.5-27.8 mN / m, a wide spin-coating window, and is suitable for 0.33NA scanning EUV exposure machines. Furthermore, the EUV photoresist prepared by this application has a shelf life of ≥6 months (4℃, protected from light), a viscosity change rate of ≤4%, a particle size increase of ≤3 pcs / mL, and excellent stability during transportation and storage.

[0045] Thirdly, this application provides an application of a high-intensity extreme ultraviolet photoresist in a patterning method, employing the following technical solution:

[0046] The application of a high-intensity extreme ultraviolet photoresist in a patterning method includes the following steps:

[0047] The above-mentioned extreme ultraviolet photoresist is spin-coated onto a substrate, then exposed to extreme ultraviolet light, and subsequently dried and developed to obtain a patterned structure.

[0048] In the technical solution of this application, the thickness of the thin film formed by coating the extreme ultraviolet photoresist on the substrate is 40-100nm.

[0049] In the technical solution of this application, the substrate is a silicon wafer, SOI, SiN, or a metal hard mask. These substrates exhibit adhesion to the EOCL adhesive layer ≥60MPa, and show no peeling during development.

[0050] In the scheme of this application, the specific process of spin coating is as follows: first, spread the coating at a speed of 450-550 rpm for 4-6 seconds, and then form a film at a speed of 2500-4000 rpm for 30-45 seconds, with a thickness non-uniformity of ≤0.4%.

[0051] In the technical solution of this application, the exposure method is a scanning extreme ultraviolet lithography machine with a numerical aperture NA=0.33, a partial coherence factor σ=0.8, an irradiation dose window ≥15%, and an exposure dose of 8-22 mJ / cm². 2 .

[0052] In the technical solution of this application, the drying temperature is 100-120℃ and the time is 60-90s.

[0053] In the technical solution of this application, the development is carried out with a 0.26N TMAH aqueous solution for a time of 10-25s.

[0054] Preferably, the resolution of the patterned structure is ≤16nm, the aspect ratio is 1:(1-4), and the sidewall angle is 86-90°.

[0055] By adopting the above technical solution, the extreme ultraviolet photoresist of this application can form patterned structures with high resolution, suitable aspect ratio and near vertical sidewall corners in patterning applications, which can be well adapted to the needs of 2nm node semiconductors and related fine manufacturing.

[0056] After verification through practical applications, the above-mentioned patterned structure can be applied to electronic devices, such as 2nm node FinFETs, GAA-FETs, or DRAM capacitors. These devices have a gate linewidth ≤16nm and a linewidth uniformity σ ≤1.2nm. This demonstrates that the patterned structure obtained from the extreme ultraviolet photoresist of this application, when applied to electronic devices, enables the devices to meet the 2nm node requirements, possessing not only a smaller gate linewidth but also ensuring good linewidth uniformity.

[0057] In summary, this application has the following beneficial technical effects:

[0058] 1. The EOCL of this application enables the photoresist to have an exposure dose ≤22mJ / cm at a wavelength of 13.5nm. 2 It can achieve a semi-dense pattern resolution of ≤16nm, solving the problem of insufficient resolution in existing systems;

[0059] 2. The glass transition temperature Tg of the EOCL in this application is ≥175℃, E′@180℃ is ≥3.2GPa, and the Tg decreases by ≤2℃ after aging at 85℃ / 85%RH for 168h after film formation, which solves the problems of low glass transition temperature and poor thermomechanical stability of the existing system.

[0060] 3. The extreme ultraviolet photoresist of this application has a development swelling rate of ≤3%, a line width roughness (LWR) of ≤2.2nm after development, and a local critical size uniformity (LCDU) of ≤1.8nm, which solves the problems of severe swelling and large line width roughness in the existing system.

[0061] 4. The extreme ultraviolet photoresist of this application has a more suitable photon absorption capability for 13.5nm extreme ultraviolet light, which is less likely to cause bubble generation and pattern collapse problems. In addition, the residual amount of metal ions in the system is low, which is less likely to have an adverse effect on the reliability of the device. Detailed Implementation

[0062] The following detailed description, in conjunction with embodiments, further illustrates this application. Unless otherwise specified, the raw materials used in this application are readily available through conventional commercial channels. All synthesis and testing were performed in a Class 1000 cleanroom at 23±1°C and 45±5%RH. All monomers, solvents, and additives were semiconductor grade, with a metal ion content ≤1 ppb. Batch-to-batch repeatability was considered acceptable with σ ≤3%.

[0063] Preparation Example 1

[0064] The ethylene oxide-caprolactam block copolymer was prepared by the following method:

[0065] S1. Add 1L of anhydrous tetrahydrofuran (THF, water ≤2ppm) to a 2L 316L stainless steel reactor that has undergone electrolytic polishing (Ra=0.125μm). After purging with nitrogen 6 times, cool to -30℃. Weigh 1.02g of potassium bis(trimethylsilyl)amino (KHMDS) (5.1mmol, 1% of the total monomer mass) and dissolve it in 20mL of anhydrous THF. Press the solution into the reactor through a 0.1μm PTFE filter and start magnetic stirring at 400rpm. Add 56.5g (0.5mol) of caprolactam (CL) using a metering pump, controlling the feeding rate at 25g / h, with the temperature fluctuation inside the reactor ≤±0.3℃. After the CL is added, maintain the temperature at -30℃ and react for 45min. Detect the amide I band at 1650 / cm using in-situ FT-IR. If the conversion rate is ≥98%, proceed to the next step.

[0066] S2. Add 64.9 g (1.475 mol) of ethylene oxide (EO) to the system from step S1 in one step, heat to -10℃ and continue polymerization for 70 min; take samples in real time. 1 H-NMR (CDCl3) showed the disappearance of the epoxy signal at σ=2.75ppm, indicating a total monomer conversion rate ≥97%.

[0067] S3. Add 150 mL of degassed methanol to the system in step S2 to terminate the reaction, then let it stand at -10℃ for 2 h, filter the white precipitate through a 0.05 μm PTFE filter, and then dry it under vacuum at 40℃ for 12 h to obtain 118.3 g of EOCL-70 resin (x=70mol%, y=30mol%), with a yield of 93.0%.

[0068] Gel permeation chromatography (GPC) analysis showed that the number-average molecular weight (Mn) of the EOCL-70 resin was 7800 g / mol, and the molecular weight distribution (K) was 1.18. Differential scanning calorimetry (DSC) analysis showed that the Tg of the EOCL-70 resin was 175℃, with no melting peak. Dynamic thermomechanical analysis (DMA) (1 Hz) analysis showed that E′@180℃ = 3.2 GPa. Inductively coupled plasma mass spectrometry (ICP-MS) analysis showed that Na... + The content is 1.3 ppb, K + The content is 0.8 ppb, Fe 3+ The content is 0.5 ppb, the total metal ion content is ≤3.5 ppm, and it can be directly used for rubber formulation; the acid value is 0.038 mg KOH / g, and the moisture content is 380 ppm.

[0069] Preparation Example 2

[0070] The ethylene oxide-caprolactam block copolymer was prepared by the following method:

[0071] S1. Add 1L of anhydrous tetrahydrofuran (THF, water ≤2ppm) to a 2L 316L stainless steel reactor that has undergone electrolytic polishing (Ra=0.125μm). After purging with nitrogen 6 times, cool to -10℃. Weigh 1.35g of potassium bis(trimethylsilyl)amino (KHMDS) (6.7mmol, 1.2% of the total monomer mass) and dissolve it in 20mL of anhydrous THF. Press the solution into the reactor through a 0.1μm PTFE filter and start magnetic stirring at 400rpm. Add 42.4g (0.375mol) of caprolactam (CL) using a metering pump, controlling the feeding rate at 25g / h, and ensuring the temperature fluctuation inside the reactor is ≤±0.3℃. After the CL is added, maintain the temperature at -10℃ and react for 35min. Detect the amide I band at 1650 / cm using in-situ FT-IR. If the conversion rate is ≥98%, proceed to the next step.

[0072] S2. Add 74.8 g (1.7 mol) of ethylene oxide (EO) to the system from step S1 in one step, heat to 10 °C and continue polymerization for 50 min; take samples in real time. 1 H-NMR (CDCl3) showed the disappearance of the epoxy signal at σ=2.75ppm, indicating a total monomer conversion rate ≥97%.

[0073] S3. Add 150 mL of degassed methanol to the system in step S2 to terminate the reaction, then let it stand at -10℃ for 2 h, filter the white precipitate through a 0.05 μm PTFE filter, and then dry it under vacuum at 40℃ for 12 h to obtain 113.6 g of EOCL-75 resin (x=75mol%, y=25mol%), with a yield of 92.8%.

[0074] Gel permeation chromatography (GPC) analysis showed that the number-average molecular weight (Mn) of the EOCL-75 resin was 10000 g / mol, and the molecular weight distribution (K) was 1.19. Differential scanning calorimetry (DSC) analysis showed that the Tg of the EOCL-75 resin was 179℃, with no melting peak. Dynamic thermomechanical analysis (DMA) (1 Hz) analysis showed that E′@180℃ = 3.3 GPa. Inductively coupled plasma mass spectrometry (ICP-MS) analysis showed that Na... + The content is 1.0 ppb, K + The content is 0.6 ppb, Fe 3+ The content is 0.3 ppb, the total metal ion content is ≤2.8 ppm, and it can be directly used for rubber formulation; the acid value is 0.035 mg KOH / g, and the moisture content is 360 ppm.

[0075] Preparation Example 3

[0076] The ethylene oxide-caprolactam block copolymer was prepared by the following method:

[0077] S1. Add 1L of anhydrous tetrahydrofuran (THF, water ≤2ppm) to a 2L 316L stainless steel reactor that has undergone electrolytic polishing (Ra=0.125μm). After purging with nitrogen 6 times, cool to -20℃. Weigh 0.87g (4.3mmol, 1.1% of the total monomer mass) of potassium bis(trimethylsilyl)amino (KHMDS) and dissolve it in 20mL of anhydrous THF. Press the solution into the reactor through a 0.1μm PTFE filter and start magnetic stirring at 400rpm. Add 39.6g (0.35mol) of caprolactam (CL) using a metering pump, controlling the feeding rate at 25g / h, and ensuring the temperature fluctuation inside the reactor is ≤±0.3℃. After the CL is added, maintain the temperature at -20℃ and react for 40min. Detect the amide I band at 1650 / cm using in-situ FT-IR. If the conversion rate is ≥98%, proceed to the next step.

[0078] S2. Add 39.6 g (0.9 mol) of ethylene oxide (EO) to the system from step S1 in one step, raise the temperature to 0°C and continue polymerization for 60 min; take samples in real time. 1 H-NMR (CDCl3) showed the disappearance of the epoxy signal at σ=2.75ppm, indicating a total monomer conversion rate ≥97%.

[0079] S3. Add 150 mL of degassed methanol to the system in step S2 to terminate the reaction, then let it stand at -10℃ for 2 h, filter the white precipitate through a 0.05 μm PTFE filter, and then dry it under vacuum at 40℃ for 12 h to obtain 75.8 g of EOCL-72 resin (x=72mol%, y=28mol%), with a yield of 95.7%.

[0080] Gel permeation chromatography (GPC) analysis showed that the number-average molecular weight (Mn) of the EOCL-72 resin was 8300 g / mol, and the molecular weight distribution (K) was 1.16. Differential scanning calorimetry (DSC) analysis showed that the Tg of the EOCL-72 resin was 177℃, with no melting peak. Dynamic thermomechanical analysis (DMA) (1 Hz) analysis showed that E′@180℃ = 3.25 GPa, tanб = 0.04 (storage modulus at 180℃ is 3.25 GPa, and the loss factor under stress and wear is 0.04). Inductively coupled plasma mass spectrometry (ICP-MS) analysis showed that Na... + The content is 1.1 ppb, K + The content is 0.7 ppb, Fe 3+ The content is 0.4 ppb, the total metal ion content is ≤4 ppm, and it can be directly used for rubber formulation; the acid value is 0.036 mg KOH / g, and the moisture content is 370 ppm.

[0081] Taking Preparation Example 3 as an example, the EOCL-72 resin was subjected to high-temperature rheological testing before resist preparation: under nitrogen protection, the temperature was increased to 250°C at a rate of 2°C / min. The storage modulus E′ remained >2.8 GPa, and the peak value of the loss factor tanб did not show significant shift, indicating that the resin's thermal decomposition temperature is >300°C, which can meet the requirements of subsequent baking and etching processes above 120°C. Compared with traditional ESCAP resin (Tg≈155°C), EOCL-72 has an increased storage modulus of about 40% at 180°C, providing dimensional assurance for high-temperature hard mask deposition.

[0082] To further verify batch stability, five batches of preparation experiments were conducted independently and consecutively in the same reactor (each batch aimed to produce 75.8 g of EOCL resin, with the same raw material usage as in Preparation Example 3). Key parameters were statistically analyzed as follows: the number-average molecular weight (Mn) of the obtained EOCL resin fluctuated between 8250 and 8400 g / mol, with a relative standard deviation (RSD) of 0.8%; the temperature range (Tg) was 176-178℃, with an RSD of 0.4%; the total metal ion content was 3.8-4.0 ppm, with an RSD of 6.2%, all within the preset specifications. These five batches were independent preparations, with each batch following the same process parameters from the beginning, completing the polymerization, termination, and purification processes. This verifies that the preparation method of this application has good process repeatability and can be directly connected to a ton-scale reactor for large-scale production.

[0083] Comparative Preparation Example 1

[0084] In the same reaction apparatus as in Preparation Example 3, only CL was added without EO to prepare polycaprolactam homopolymer (PCL) as a reference. The specific process is as follows:

[0085] 1 L of anhydrous tetrahydrofuran (THF, water ≤ 2 ppm) was added to a 2 L 316L stainless steel reactor that had undergone electrolytic polishing (Ra = 0.125 μm). After purging with nitrogen 6 times, the reactor was cooled to -20 °C. 0.87 g (4.3 mmol) of potassium bis(trimethylsilyl)amino (KHMDS) was weighed and dissolved in 20 mL of anhydrous THF. The mixture was then subjected to 0.1 μm... A PTFE filter was pressed into the reactor, and a magnetic stirrer was started at 400 rpm. 79.2 g of caprolactam (CL) was added using a metering pump at a rate of 25 g / h, with the temperature fluctuation inside the reactor ≤ ±0.5℃. After the CL was added, the reactor was maintained at -20℃ for 30 min. In-situ FT-IR detection of the amide I band at 1650 cm⁻¹ confirmed a monomer conversion rate ≥ 98%. 150 mL of degassed methanol was added to terminate the reaction. The mixture was then allowed to stand at -10℃ for 2 h before filtration. Afterward, it was vacuum dried at 40℃ for 12 h to obtain 88.4 g of polycaprolactam homopolymer (PCL), with a yield of 92.3%.

[0086] Gel permeation chromatography (GPC) analysis showed that although the number-average molecular weight (Mn) of the PCL was 8000 g / mol and the molecular weight distribution (Đ) was 1.15, differential scanning calorimetry (DSC) analysis showed that the Tg of the PCL was 185℃. However, dynamic thermomechanical analysis (DMA, 1 Hz) analysis showed that E′@180℃ = 4.1 GPa, indicating relatively high brittleness. Furthermore, inductively coupled plasma mass spectrometry (ICP-MS) analysis showed that the total metal ion content was 38 ppm.

[0087] Comparative Preparation Example 2

[0088] In the same reaction apparatus as in Preparation Example 3, only EO was added without CL to prepare a polyethylene oxide homopolymer (PEO) as a reference. The specific process is as follows:

[0089] 1L of anhydrous tetrahydrofuran (THF, water ≤2ppm) was added to a 2L 316L stainless steel reactor that had undergone electrolytic polishing (Ra=0.125μm). After purging with nitrogen 6 times, the reactor was cooled to -20℃. 0.87g (4.3mmol) of potassium bis(trimethylsilyl)amino (KHMDS) was weighed and dissolved in 20mL of anhydrous THF. The solution was then forced into the reactor through a 0.1μm PTFE filter. Magnetic stirring was started at 400rpm. 79.2g of ethylene oxide (EO) was added using a metering pump at a rate of 25g / h, with temperature fluctuations within the reactor ≤±0.5℃. After the EO addition was complete, the reactor was maintained at -20℃ and reacted for 30min. The characteristic peak of the 910 / cm epoxy group was detected by in-situ FT-IR. 1H-NMR showed an epoxy signal of σ=2.75ppm. When the monomer conversion rate was confirmed to be ≥98%, 150mL of degassed methanol was added to the system to terminate the reaction. After standing at -10℃ for 2h, the mixture was filtered and then dried under vacuum at 40℃ for 12h to obtain 88.2g of polyethylene oxide homopolymer (PEO), with a yield of 92.1%.

[0090] Gel permeation chromatography (GPC) analysis showed that the number-average molecular weight (Mn) of the PEO was 7500 g / mol, and the molecular weight distribution (Đ) was 1.18. Differential scanning calorimetry (DSC) analysis showed that the Tg of the PEO was -55℃ (far lower than the 177℃ of Preparation Example 3). Dynamic thermomechanical analysis (DMA) (1 Hz) analysis showed that E′@180℃ = 0.3 GPa (only 1 / 10 of that of Preparation Example 3). Inductively coupled plasma mass spectrometry (ICP-MS) analysis showed that the total metal ion content was 12 ppm, the acid value was 0.05 mg KOH / g, and the water content was 450 ppm.

[0091] Comparative preparation example 3

[0092] The difference from Preparation Example 3 is that a sequential feeding method was not used; specifically:

[0093] 1L of anhydrous tetrahydrofuran (THF, water ≤2ppm) was added to a 2L 316L stainless steel reactor that had undergone electrolytic polishing (Ra=0.125μm). After purging with nitrogen 6 times, the reactor was cooled to -20℃. 0.87g (4.3mmol, 1.1% of the total monomer mass) of potassium bis(trimethylsilyl)amino (KHMDS) was weighed and dissolved in 20mL of anhydrous THF. The solution was then forced into the reactor through a 0.1μm PTFE filter. Magnetic stirring was started at 400rpm. 39.6g (0.35mol) of caprolactam (CL) and 39.6g (0.9mol) of ethylene oxide (EO) were simultaneously added using a metering pump at a rate of 25g / h, with temperature fluctuations within the reactor ≤±0.5℃. After addition, the reactor was maintained at -20℃ for 30min. In-situ FT-IR was used to detect the amide I band at 1650 / cm². 1 H-NMR (CDCl3) showed the disappearance of the epoxy signal at σ=2.75ppm, confirming that the total monomer conversion was ≥95%. The reaction was terminated by adding 150mL of degassed methanol to the system, and then allowed to stand at -10℃ for 2h. The white precipitate was then filtered through a 0.05μm PTFE filter and subsequently dried under vacuum at 40℃ for 12h to obtain 85.3g of the non-sequentially fed copolymer EOCL-mix (x=72mol%, y=28mol%), with a yield of 86.2%.

[0094] Gel permeation chromatography (GPC) analysis showed that the number-average molecular weight (Mn) of this EOCL-mix was 7800 g / mol, and the molecular weight distribution (K) was 1.42 (significantly wider than 1.16 in Preparation Example 3). Differential scanning calorimetry (DSC) analysis showed that the Tg of this EOCL-mix was 168 °C (lower than 177 °C in Preparation Example 3). Inductively coupled plasma mass spectrometry (ICP-MS) analysis showed that Na... + The content is 3.8 ppb, Fe 3+ The content was 2.3 ppb, the total metal ion content was 15 ppm (both higher than that of Preparation Example 3); the acid value was 0.07 mg KOH / g, and the moisture content was 580 ppm (both exceeding the control range of Preparation Example 3).

[0095] Comparative preparation example 4

[0096] The difference from Preparation Example 3 is that in the EOCL resin, x = 80 mol%, y = 20 mol%; specifically:

[0097] S1. Add 1L of anhydrous tetrahydrofuran (THF, water ≤2ppm) to a 2L 316L stainless steel reactor that has undergone electrolytic polishing (Ra=0.125μm). After purging with nitrogen 6 times, cool to -20℃. Weigh 1.25g of potassium bis(trimethylsilyl)amino (KHMDS) (6.3mmol, 1.1% of the total monomer mass) and dissolve it in 20mL of anhydrous THF. Press the solution into the reactor through a 0.1μm PTFE filter and start magnetic stirring at 400rpm. Add 34.0g (0.3mol) of caprolactam (CL) using a metering pump, controlling the feeding rate at 25g / h, with temperature fluctuations within the reactor ≤±0.3℃. After the CL is added, maintain the temperature at -20℃ and react for 40min. Detect the amide I band at 1650 / cm using in-situ FT-IR. If the conversion rate is ≥98%, proceed to the next step.

[0098] S2. Add 79.2 g (1.8 mol) of ethylene oxide (EO) to the system from step S1 in one step, raise the temperature to 0°C and continue polymerization for 60 min; take samples in real time. 1 H-NMR (CDCl3) showed the disappearance of the epoxy signal at σ=2.75ppm, indicating a total monomer conversion rate ≥97%.

[0099] S3. Add 150 mL of degassed methanol to the system in step S2 to terminate the reaction, then let it stand at -10℃ for 2 h, filter the white precipitate through a 0.05 μm PTFE filter, and then dry it under vacuum at 40℃ for 12 h to obtain 108.5 g of EOCL-80 resin with high EO content, with a yield of 93.4%.

[0100] Gel permeation chromatography (GPC) analysis showed that the number-average molecular weight (Mn) of the EOCL-80 resin was 8300 g / mol, and the molecular weight distribution (K) was 1.22 (slightly higher than the 1.16 of Preparation Example 3). Differential scanning calorimetry (DSC) analysis showed that the Tg of the EOCL-80 resin was 152 °C (significantly lower than the 177 °C of Preparation Example 3). Dynamic thermomechanical analysis (DMA) (1 Hz) analysis showed that E′@180 °C was 2.1 GPa (significantly lower than the 3.25 GPa of Preparation Example 3). Inductively coupled plasma mass spectrometry (ICP-MS) analysis showed that the total metal ion content was 8 ppm, the acid value was 0.045 mg KOH / g, and the moisture content was 420 ppm (all exceeding the control range of Preparation Example 3).

[0101] Comparative preparation example 5

[0102] The difference from Preparation Example 3 is that the EOCL resin contains x = 65 mol%, y = 35 mol%; specifically:

[0103] S1. Add 1L of anhydrous tetrahydrofuran (THF, water ≤2ppm) to a 2L 316L stainless steel reactor that has undergone electrolytic polishing (Ra=0.125μm). After purging with nitrogen 6 times, cool to -20℃. Weigh 1.58g of potassium bis(trimethylsilyl)amino (KHMDS) (7.9mmol, 1.1% of the total monomer mass) and dissolve it in 20mL of anhydrous THF. Press the solution into the reactor through a 0.1μm PTFE filter and start magnetic stirring at 400rpm. Add 63.3g (0.5625mol) of caprolactam (CL) using a metering pump, controlling the feeding rate at 25g / h, and ensuring the temperature fluctuation inside the reactor is ≤±0.3℃. After the CL is added, maintain the temperature at -20℃ and react for 40min. Detect the amide I band at 1650 / cm using in-situ FT-IR. If the conversion rate is ≥98%, proceed to the next step.

[0104] S2. Add 79.2 g (1.8 mol) of ethylene oxide (EO) to the system from step S1 in one step, raise the temperature to 0°C and continue polymerization for 60 min; take samples in real time. 1 H-NMR (CDCl3) showed the disappearance of the epoxy signal at σ=2.75ppm, indicating a total monomer conversion rate ≥97%.

[0105] S3. Add 150 mL of degassed methanol to the system in step S2 to terminate the reaction, then let it stand at -10℃ for 2 h, filter the white precipitate through a 0.05 μm PTFE filter, and then dry it under vacuum at 40℃ for 12 h to obtain 136.8 g of EOCL-65 resin with a high CL content, with a yield of 94.1%.

[0106] Gel permeation chromatography (GPC) analysis showed that the number-average molecular weight (Mn) of the EOCL-65 resin was 8500 g / mol, and the molecular weight distribution (K) was 1.21 (slightly higher than the 1.16 of Preparation Example 3). Differential scanning calorimetry (DSC) analysis showed that the Tg of the EOCL-65 resin was 188 °C. Dynamic thermomechanical analysis (DMA) (1 Hz) analysis showed that E′@180 °C was 4.5 GPa (significantly higher than the 3.25 GPa of Preparation Example 3, indicating increased brittleness). Inductively coupled plasma mass spectrometry (ICP-MS) analysis showed that the total metal ion content was 9 ppm, the acid value was 0.042 mg KOH / g, and the moisture content was 410 ppm (all exceeding the control range of Preparation Example 3).

[0107] Example 1

[0108] A method for preparing a high-strength extreme ultraviolet photoresist includes the following steps:

[0109] I. Raw material pretreatment: The EOCL-70 resin obtained in Preparation Example 1 was dried in a vacuum drying oven at 75°C for 4.5 hours, controlling the moisture content to ≤0.05%; the photoacid-generating agent and crosslinking agent were purified by silica gel column chromatography to ensure a purity ≥99.5%; the solvent was dehydrated by passing it through a molecular sieve to ensure a moisture content ≤0.05%.

[0110] II. In a Class 100 glove box, under nitrogen protection, 18g of EOCL-70 resin was dissolved in 181.48g of a mixed solvent of γ-butyrolactone / propylene glycol methyl ether acetate (the weight ratio of γ-butyrolactone to propylene glycol methyl ether acetate was 6:4). The mixture was stirred at 250 rpm for 2.5 hours at room temperature until the EOCL-70 resin was completely dissolved. Then, 0.3g of photoacid-generating agent triphenylsulfonium trifluoromethanesulfonate, 0.2g of crosslinking agent tris(4-phenylisocyanate)methane, 0.01g of leveling agent polyether siloxane (BYK-333), and 0.01g of antioxidant 2,6-di-tert-butyl-4-methylphenol were added sequentially and the mixture was stirred for another 4.5 hours to form a uniform and transparent mixture.

[0111] III. Filtration and degassing: The mixture obtained in step II was filtered three times through a 0.22μm nylon filter to obtain a clear photoresist solution. The solid content was 9wt%, the viscosity at 25℃ was 4.8cp (Brookfield DV2T, shear rate 100 / s), and the surface tension was 25.5mN / m. The solution was dispensed into 100mL brown HDPE bottles, sealed with nitrogen, and stored at 4℃ in the dark.

[0112] Periodic sampling (0d, 30d, 60d, 90d, 180d): viscosity changed from 4.8cp to 4.98cp, a change rate of 3.7%; particle count in 0.2μm liquid particle counter changed from 9 to 12 pcs / mL; acid value titration (ASTM D664) changed from 0.031 to 0.036 mgKOH / g, with no significant hydrolysis; storage period ≥ 6 months, meeting mass production requirements.

[0113] Example 2

[0114] A method for preparing a high-strength extreme ultraviolet photoresist includes the following steps:

[0115] I. Raw material pretreatment: The EOCL-75 resin obtained in Preparation Example 2 was dried in a vacuum drying oven at 85℃ for 3.5h, controlling the moisture content to ≤0.05%; the photoacid-generating agent and crosslinking agent were purified by silica gel column chromatography to ensure purity ≥99.5%; the solvent was dehydrated by passing it through a molecular sieve to ensure moisture content ≤0.05%.

[0116] II. In a Class 100 glove box, under nitrogen protection, 24g of EOCL-70 resin was dissolved in 175.16g of a mixed solvent of γ-butyrolactone / propylene glycol methyl ether acetate (the weight ratio of γ-butyrolactone to propylene glycol methyl ether acetate was 6:4). The mixture was stirred at 350 rpm for 1.5 hours at room temperature until the EOCL-75 resin was completely dissolved. Then, 0.5g of photoacid-generating agent triphenylsulfonium trifluoromethanesulfonate, 0.3g of crosslinking agent tris(4-phenylisocyanate)methane, 0.02g of leveling agent polyether siloxane (BYK-333), and 0.02g of antioxidant 2,6-di-tert-butyl-4-methylphenol were added sequentially and the mixture was stirred for another 3.5 hours to form a uniform and transparent mixture.

[0117] III. Filtration and degassing: The mixture obtained in step II was filtered three times through a 0.22μm nylon filter to obtain a clear photoresist solution. The solid content was 12wt%, the viscosity at 25℃ was 5.5cp (Brookfield DV2T, shear rate 100 / s), and the surface tension was 27.8mN / m. The solution was dispensed into 100mL brown HDPE bottles, sealed with nitrogen, and stored at 4℃ in the dark.

[0118] Periodic sampling (0d, 30d, 60d, 90d, 180d): viscosity changed from 5.5cp to 5.68cp, a change rate of 3.3%; particle count in the 0.2μm liquid particle counter changed from 11 to 14 pcs / mL; acid value titration (ASTM D664) changed from 0.033 to 0.038 mgKOH / g, with no significant hydrolysis; storage period ≥ 6 months, meeting mass production requirements.

[0119] Example 3

[0120] A method for preparing a high-strength extreme ultraviolet photoresist includes the following steps:

[0121] I. Raw material pretreatment: The EOCL-72 resin obtained in Preparation Example 3 was dried in a vacuum drying oven at 80℃ for 4 hours, controlling the moisture content to ≤0.05%; the photoacid-generating agent and crosslinking agent were purified by silica gel column chromatography to ensure a purity ≥99.5%; the solvent was dehydrated by passing it through a molecular sieve to ensure a moisture content ≤0.05%.

[0122] II. In a Class 100 glove box, under nitrogen protection, 20g of EOCL-72 resin was dissolved in 179.33g of a mixed solvent of γ-butyrolactone / propylene glycol methyl ether acetate (the weight ratio of γ-butyrolactone to propylene glycol methyl ether acetate was 6:4). The mixture was stirred at 300rpm for 2 hours at room temperature until the EOCL-72 resin was completely dissolved. Then, 0.4g of photoacid-generating agent triphenylsulfonium trifluoromethanesulfonate, 0.24g of crosslinking agent tris(4-phenylisocyanate)methane, 0.02g of leveling agent polyether siloxane (BYK-333), and 0.01g of antioxidant 2,6-di-tert-butyl-4-methylphenol were added sequentially and the mixture was stirred for another 4 hours to form a uniform and transparent mixture.

[0123] III. Filtration and degassing: The mixture obtained in step II was filtered three times through a 0.22μm nylon filter to obtain a clear photoresist solution. The solid content was 10wt%, the viscosity at 25℃ was 5.1cp (Brookfield DV2T, shear rate 100 / s), and the surface tension was 26.8mN / m. The solution was dispensed into 100mL brown HDPE bottles, sealed with nitrogen, and stored at 4℃ in the dark.

[0124] Periodic sampling (0d, 30d, 60d, 90d, 180d): Viscosity changed from 5.1cp to 5.28cp, a change rate of 3.5%; particle count using a 0.2μm liquid particle counter changed from 10 to 13 pcs / mL; acid value titration (ASTM D664) changed from 0.032 to 0.037 mgKOH / g, with no significant hydrolysis; storage period ≥ 6 months, meeting mass production requirements. Simultaneously, metal ion migration was determined: Na... + The content increased from 1.8 ppb to 2.1 ppb, K + The content increased from 1.2 ppb to 1.4 ppb, with each increase being less than 0.5 ppb, indicating that there was no additional metal contamination during storage, meeting the wafer fab's ≤8 ppb specification requirement.

[0125] Taking Example 3 as an example, high-temperature accelerated aging was investigated. Another 30 mL of photoresist solution was placed in a 60°C oven and dried for 14 days (equivalent to 6 months at room temperature). The viscosity increased to 5.45 cp, with a change rate of 6.9%, still below the 10% warning line. GC-MS analysis of the solvent composition showed that the weight ratio of γ-butyrolactone to propylene glycol methyl ether acetate changed from 6:4 to 5.9:4.1, with a mixing loss of <2%, indicating that the solvent system was stable and no significant phase separation or hydrolysis-induced increase in acid value was observed. In contrast, traditional ESCAP photoresist with the same solid content showed a significant performance degradation after 3 months of storage at 4°C, with viscosity increasing from 5.3 cp to 6.1 cp (+15%), particle count increasing from 15 pcs / mL to 45 pcs / mL, and acid value increasing from 0.05 mg KOH / g to 0.12 mg KOH / g.

[0126] Comparative Example 1

[0127] The difference from Example 3 is that the EOCL-72 resin prepared in Example 3 was replaced with the polycaprolactam copolymer prepared in Comparative Example 1, and then the photoresist was prepared according to the same process as in Example 1.

[0128] Testing revealed that the photoresist had a solid content of 10 wt%, a viscosity of 7.2 cp at 25°C (poor fluidity, prone to pinholes and craters during spin coating), a surface roughness Rq of 0.52 nm after spin coating (significantly worse than 0.16 nm in Example 3), an internal stress of 26 MPa (higher than 11 MPa in Example 3), and a spontaneous crack density of 2.3 / cm. After 6 months of storage at 4°C, the viscosity change rate was 7.5% (higher than 3.5% in Example 3), and the acid value increased from 0.04 mg KOH / g to 0.09 mg KOH / g, indicating significant stratification and hydrolysis.

[0129] Comparative Example 2

[0130] The difference from Example 3 is that the EOCL-72 resin prepared in Example 3 was replaced with the polyethylene oxide homopolymer prepared in Comparative Example 2, and then the photoresist was prepared according to the same process as in Example 1.

[0131] The photoresist was found to have a solid content of 10 wt%, a viscosity of 3.2 cp at 25°C (too fluid to be stable for spin coating), and a viscosity change rate of 12.5% ​​after storage at 4°C for one month (higher than the 3.5% in Example 3), indicating significant layering and hydrolysis.

[0132] Comparative Example 3

[0133] The difference from Example 3 is that the EOCL-72 resin prepared in Preparation Example 3 was replaced with the EOCL-mixed resin prepared in Comparative Preparation Example 3, and then the photoresist was prepared according to the same process as in Example 1.

[0134] The photoresist was found to have a solid content of 10 wt%, a viscosity of 6.3 cp at 25°C (with greater fluctuation than in Example 3), and a viscosity change rate of 8.2% after storage at 4°C for 3 months (higher than the 3.5% in Example 3).

[0135] Comparative Example 4

[0136] The difference from Example 3 is that the EOCL-72 resin prepared in Example 3 was replaced with the EOCL-80 resin prepared in Comparative Example 4, and then the photoresist was prepared according to the same process as in Example 1.

[0137] The photoresist was found to have a solid content of 10 wt%, a viscosity of 4.2 cp at 25°C, and a viscosity change rate of 5.8% after 6 months of storage at 4°C (higher than the 3.5% in Example 3).

[0138] Comparative Example 5

[0139] The difference from Example 3 is that the EOCL-72 resin prepared in Example 3 was replaced with the EOCL-65 resin prepared in Comparative Example 5, and then the photoresist was prepared according to the same process as in Example 1.

[0140] The photoresist was found to have a solid content of 10 wt%, a viscosity of 6.8 cp at 25°C (poor flowability, which makes it prone to pinholes when spin-coated), and a viscosity change rate of 4.2% after 6 months of storage at 4°C (higher than the 3.5% in Example 3).

[0141] Application Example 1

[0142] The application of a high-intensity extreme ultraviolet photoresist in a patterning method includes the following steps:

[0143] a. Take a 300mm silicon wafer (with a 20nm SiN antireflective layer sputtered), apply HMDS vapor phase Prime at 120℃ for 60s, with a water contact angle of 67°; use a TEL ACT-12 coating machine, employing the photoresist solution prepared in Example 1, first spread it at 450rpm for 6s, then form a film at 2500rpm for 45s, aiming to form a 40nm thick film, and then soft bake it on a hot plate at 100℃ for 60s, with hot plate uniformity ±0.2℃ (9-point check).

[0144] Ellipsometry (SpectraFilm LD10) 49-point mapping: average film thickness 39.8 nm, σ = 0.25 nm, thickness non-uniformity 0.4%, AFM (2 × 2 μm) 2 Rq=0.17nm, which meets the high resolution requirement; the linear absorption coefficient of the film was tested using a UV-Vis-NIR spectrophotometer, and μ=0.28 / μm was measured at an extreme ultraviolet wavelength of 13.5nm. This ensures sufficient photon absorption for efficient acid production, while avoiding the problems of bubbles and pattern collapse caused by excessive absorption.

[0145] b. The silicon wafer formed in step a is fed into a scanning extreme ultraviolet lithography machine ASML NXE:3600D (NA=0.33, σ=0.8, 13.5nm), with a dose matrix of 8-18mJ / cm. 2 (Step length 2mJ), cavity temperature 22.0±0.1℃, He back pressure ≤5×10 - 8 mbar; immediately after exposure, PEB was baked at 100℃ for 60s, with hot plate uniformity ±0.4℃; the random simulated acid diffusion length was 5.2nm, balancing sensitivity and LWR; then, 0.26N TMAH aqueous solution was used for development by covering and allowing the puddle to stand for 10s, followed by rinsing with deionized water for 30s, and drying with nitrogen to obtain the patterned structure.

[0146] The change in film thickness before and after development was measured by an ellipsometry, and the development swelling rate was calculated. The development swelling rate = (maximum thickness after development - thickness before development) / thickness before development × 100% = (40.9nm - 39.8nm) / 39.8nm × 100% ≈ 2.8% (< 3%). There was no obvious swelling during the development process, which ensured the accuracy of the line width dimensions.

[0147] The 16 nm semi-dense line space was measured by critical-size scanning electron microscopy (CD-SEM) (1 kV, 8 Pa): the optimal dose was 18 mJ / cm. 2 CD=15.8nm, LWR=2.1nm (3σ, 200 segments), LCDU=1.75nm; KLA SP5 defects: bridging defects 0.007 / cm 2 No residue was found; the X-SEM aspect ratio was 1:1 and the sidewall angle was 86°, which met the requirements for subsequent SiO2 hard mask etching.

[0148] Application Example 2

[0149] The application of a high-intensity extreme ultraviolet photoresist in a patterning method includes the following steps:

[0150] a. Take a 300mm silicon wafer (with a 20nm SiN antireflective layer sputtered), apply HMDS vapor phase Prime at 120℃ for 60s, with a water contact angle of 67°; use a TEL ACT-12 coating machine, employing the photoresist solution prepared in Example 2, first spread it at 550rpm for 4s, then form a film at 4000rpm for 30s, aiming to form a 100nm thick film, and then soft bake it on a hot plate at 120℃ for 90s, with hot plate uniformity ±0.2℃ (9-point check).

[0151] Ellipsometry (SpectraFilm LD10) 49-point mapping: average film thickness 99.7 nm, σ = 0.32 nm, thickness non-uniformity 0.4%, AFM (2 × 2 μm) 2 Rq=0.15nm, which meets the high resolution requirement; the linear absorption coefficient of the film was tested using a UV-Vis-NIR spectrophotometer, and μ=0.38 / μm was measured at an extreme ultraviolet wavelength of 13.5nm. This ensures sufficient photon absorption for efficient acid production, while avoiding the problems of bubbles and pattern collapse caused by excessive absorption.

[0152] b. The silicon wafer formed in step a is fed into a scanning extreme ultraviolet lithography machine ASML NXE:3600D (NA=0.33, σ=0.8, 13.5nm), with a dose matrix of 20-22mJ / cm. 2 (Step length 2mJ), cavity temperature 22.0±0.1℃, He back pressure ≤5×10 - 8 mbar; immediately after exposure, PEB was baked at 120℃ for 90s, with hot plate uniformity ±0.4℃; the random simulated acid diffusion length was 5.2nm, balancing sensitivity and LWR; then, 0.26N TMAH aqueous solution was used for development by covering and allowing the puddle to stand for 25s, followed by rinsing with deionized water for 30s, and drying with nitrogen to obtain the patterned structure.

[0153] The change in film thickness before and after development was measured using an ellipsometry, and the film expansion rate was calculated to be approximately 2.5% (<3%), which is (102.2nm-99.7nm) / 99.7nm×100%. No significant swelling was observed during the development process, ensuring the accuracy of the linewidth dimensions.

[0154] The 16 nm semi-dense line space measured by critical-size scanning electron microscopy (CD-SEM, 1 kV, 8 Pa) showed an optimal dose of 22 mJ / cm². 2 CD=16.0nm, LWR=2.15nm (3σ, 200 segments), LCDU=1.8nm; KLA SP5 defects: bridging defects 0.005 / cm 2No residue was found; the X-SEM aspect ratio was 1:4 and the sidewall angle was 90°, which met the requirements for subsequent SiO2 hard mask etching.

[0155] Application Example 3

[0156] The application of a high-intensity extreme ultraviolet photoresist in a patterning method includes the following steps:

[0157] a. Take a 300mm silicon wafer (with a 20nm SiN antireflective layer sputtered), apply HMDS vapor phase Prime at 120℃ for 60s, with a water contact angle of 67°; use a TEL ACT-12 coating machine, employing the photoresist solution prepared in Example 3, first spread it at 500rpm for 5s, then form a film at 3000rpm for 40s, aiming to form a film with a thickness of 70nm, and then soft bake it on a hot plate at 100℃ for 90s, with hot plate uniformity ±0.2℃ (9-point check).

[0158] Ellipsometry (SpectraFilm LD10) 49-point mapping: average film thickness 69.7 nm, σ = 0.28 nm, thickness non-uniformity 0.4%, AFM (2 × 2 μm) 2 Rq=0.16nm, which meets the high resolution requirement; the linear absorption coefficient of the film was tested using a UV-Vis-NIR spectrophotometer, and μ=0.32 / μm was measured at an extreme ultraviolet wavelength of 13.5nm. This ensures sufficient photon absorption for efficient acid production, while avoiding the problems of bubbles and pattern collapse caused by excessive absorption.

[0159] b. The silicon wafer formed in step a is fed into a scanning extreme ultraviolet lithography machine ASML NXE:3600D (NA=0.33, σ=0.8, 13.5nm), with a dose matrix of 16-26mJ / cm. 2 (Step length 2mJ), cavity temperature 22.0±0.1℃, He back pressure ≤5×10 - 6 mbar; immediately after exposure, PEB was baked at 110℃ for 75s, with hot plate uniformity ±0.4℃; the random simulated acid diffusion length was 5.2nm, balancing sensitivity and LWR; then, 0.26N TMAH aqueous solution was used for development by covering and allowing the puddle to stand for 20s, followed by rinsing with deionized water for 30s, and drying with nitrogen to obtain the patterned structure.

[0160] The thickness change of the film before and after development was measured by ellipsometry, and its development expansion rate was calculated to be approximately 2.6% (<3%), which is (71.5nm-69.7nm) / 69.7nm×100%. There was no obvious swelling during the development process, which ensured the accuracy of the line width dimensions.

[0161] 16 nm semi-dense line space measured by critical-size scanning electron microscopy (CD-SEM, 1 kV, 8 Pa): Optimal dose 20 mJ / cm² 2 CD=15.9nm, LWR=2.05nm (3σ, 200 segments), LCDU=1.7nm; KLA SP5 defects: bridging defects 0.006 / cm 2 No residue was found; the X-SEM aspect ratio was 1:3.2 and the sidewall angle was 88°, which met the requirements for subsequent SiO2 hard mask etching.

[0162] Taking application example 3 as an example, the PEB temperature window is further broadened: 100-120℃×75s, CD change ±0.5nm, LWR increase ≤0.1nm; dose window ±10% (18-22mJ / cm). 2 The CD drift within the process is less than 0.6nm, indicating that the process margin is sufficient to accommodate fluctuations in mass production equipment.

[0163] Dry etching and thermal stability verification were performed using Application Example 3 as an example.

[0164] The patterned silicon wafer prepared in Application Example 3 was fed into a LAM Versys Kiyo 45 and etched for 40 seconds under the following conditions: gas mixture of CF4 40 sccm + CHF3 60 sccm + Ar 100 sccm, pressure of 10 mTorr, source power of 1200 W, and bias voltage of 400 W. OES at 259 nm endpoint detection showed over-etching ≤4%. Post-etching X-SEM: 48 nm of resist layer remained (approximately 22 nm loss), SiO2 trench depth was 66 nm, linewidth loss was 0.7 nm, and the etching selectivity (resin:SiO2) was 1:3, superior to the traditional acrylic system (1:1.2).

[0165] Take 2×2cm of 70nm film 2 The sample was placed in ESPEC SH-242 and aged for 168 hours at 85℃ / 85%RH. DSC: The Tg changed from 177℃ to 175.3℃ before and after aging, Δ=1.7℃; DMA E′@180℃ decreased from 3.25 to 3.18 GPa, a decrease of 2.2%; the equilibrium water absorption rate was 0.28wt%, which is 1 / 3 of that of traditional ESCAP resin; no swelling or white spots were observed after development, confirming excellent wet and heat stability.

[0166] Further thermal cycling at -40~125℃ for 1000 cycles, each cycle lasting 30 minutes, resulted in no cracking or warping of the film, with a CD change of <0.3nm. After aging at 85℃ / 85%RH for 1000 hours, the Tg decreased by 2.3℃, and the LER increase was <3%, indicating that the long-term reliability meets the requirements of automotive-grade chip packaging.

[0167] Comparative Application Example 1

[0168] Traditional bisphenol A epoxy-acrylic acid system

[0169] Referring to the EO / PO modified pyrazoline sensitizer-acrylate copolymer system photoresist disclosed in CN 113527207A, the specific preparation and properties are as follows:

[0170] (1) Preparation of film-forming resin: Styrene and glycidyl methacrylate were used as polymerizing monomers, and EO / PO modified pyrazoline sensitizer (5% by mass) was added. Alkali-soluble copolymer was prepared by free radical polymerization. The number average molecular weight Mn was 7500 g / mol, the molecular weight distribution K was 1.32, the glass transition temperature Tg was 128℃, and the metal ion content was 8.2 ppb.

[0171] (2) Photoresist preparation: According to the formula recorded in the patent, 68 kg of the above copolymer, 7 kg of triphenylsulfonate, 3 kg of ethylene glycol diglycidyl ether, and 22 kg of PGMEA solvent are mixed and dissolved, and the photoresist product is obtained after filtration and degassing.

[0172] (3) Patterning: The photoresist solution prepared in Example 3 of Application Example 3 is replaced with the photoresist solution in step (2), and a silicon wafer with a patterned structure is prepared according to the same process conditions as in Application Example 3.

[0173] The exposure dose was measured to be 35 mJ / cm². 2 Higher than 20 mJ / cm in Application Example 3 2 The resolution was 22nm, lower than the 15.9nm of Application Example 3; the development expansion rate was 8.5%, higher than the 2.6% of Application Example 3; the linewidth roughness (LWR) was 2.8nm, higher than the 2.05nm of Application Example 3, and the LCDU was 3.5nm, higher than the 1.7nm of Application Example 3; after aging at 85℃ / 85%RH for 72h, the Tg decreased to 115℃, a decrease of 13℃, and the thermal stability was significantly worse than that of Application Example 3; the etching selectivity ratio relative to SiO2 was 1:1.2, lower than the 1:3.2 of Application Example 1; the crosslinking defect was 0.18 / cm. 2 .

[0174] Comparative Application Example 2

[0175] The difference from Application Example 3 is that the photoresist solution prepared in Example 3 was replaced with the photoresist prepared in Comparative Example 1, and then a silicon wafer with a patterned structure was prepared according to the same process as in Application Example 3.

[0176] Testing revealed that it requires an exposure dose of 35 mJ / cm². 2 Higher than 20 mJ / cm in Application Example 3 2The development rate was 8.5%, much higher than that of Application Example 3, indicating severe development swelling; the resolution was 22nm, lower than the 15.9nm of Application Example 3; LWR=3.2nm, higher than the 2.05nm of Application Example 3; LCDU=3.8nm, higher than the 1.7nm of Application Example 3; after aging at 85℃ / 85%RH for 72h, the Tg dropped to 125℃, a decrease of 3℃; with a selected resist-to-SiO2 ratio of 1:1.1, the defect was 0.25 / cm. 2 These data confirm that the EO segment is crucial for reducing swelling, improving development contrast, and maintaining a high Tg.

[0177] Furthermore, the experiment revealed that the photoresist solution prepared in Comparative Example 1 exhibited internal stress >25MPa and spontaneous crack density >2 / cm immediately after spin coating, while the photoresist prepared in Example 3 had an internal stress of only 11MPa and no cracks after spin coating, further demonstrating that the introduction of the EO segment can effectively release stress and balance rigidity and toughness.

[0178] Comparative Application Example 3

[0179] The difference from Application Example 3 is that the photoresist solution prepared in Example 3 was replaced with the photoresist prepared in Comparative Example 2, and then a silicon wafer with a patterned structure was prepared according to the same process as in Application Example 3.

[0180] Testing revealed that the adhesive film failed to form a stable pattern, and the spin-coated film was prone to flow, exhibiting a thickness non-uniformity of 3.5%, significantly higher than the 0.4% in Example 3. The surface roughness Rq = 0.85 nm, and severe flow and collapse occurred after exposure, even with a reduced exposure dose to 10 mJ / cm². 2 After development, there was still no clear linewidth structure, only a blurry coating remained; during the etching process, the photoresist layer completely decomposed and had no pattern transfer capability. The test results proved that without the CL segment, the photoresist could not meet the requirements of high-temperature etching and pattern stability.

[0181] Comparative Application Example 4

[0182] The difference from Application Example 3 is that the photoresist solution prepared in Example 3 was replaced with the photoresist prepared in Comparative Example 3, and then a silicon wafer with a patterned structure was prepared according to the same process as in Application Example 3.

[0183] Testing revealed that the surface roughness Rq of the spin-coated film was 0.28 nm, which was worse than the 0.16 nm of Application Example 3; the internal stress was 18 MPa, which was higher than the 11 MPa of Application Example 3; and the required exposure dose was 28 mJ / cm². 2 Higher than 20 mJ / cm in Application Example 3 2The resolution is 18.5nm, lower than 15.9nm in Application Example 3; LWR = 2.6nm, higher than 2.05nm in Application Example 3; LCDU = 2.9nm, higher than 1.7nm in Application Example 3; after aging at 85℃ / 85%RH for 168h, Tg decreased by 3.5℃, greater than 1.7℃ in Application Example 3; etching selectivity (resin:SiO2) = 1:2.1, lower than 1:3 in Application Example 3; the defect rate is 0.08 / cm. 2 This is higher than the 0.006 / cm in Application Example 3. 2 These data confirm that non-sequential feeding leads to non-uniform copolymer block structures, which in turn affects the sensitivity, resolution, and stability of the photoresist, highlighting the critical role of the "sequential feeding" process in performance.

[0184] Comparative Application Example 5

[0185] The difference from Application Example 3 is that the photoresist solution prepared in Example 3 was replaced with the photoresist prepared in Comparative Example 4, and then a silicon wafer with a patterned structure was prepared according to the same process as in Application Example 3.

[0186] Testing revealed that the surface roughness Rq of the spin-coated film was 0.25 nm, which was worse than the 0.16 nm of Application Example 3. The internal stress was 8 MPa, lower than the 11 MPa of Application Example 3, indicating a lower stress level and a greater likelihood of deformation during subsequent etching. The required exposure dose was 16 mJ / cm². 2 The sensitivity is high, but the stability is insufficient; the resolution is 19.2 nm, lower than the 15.9 nm of Application Example 3; slight swelling occurs after development; LWR=2.8 nm, higher than the 2.05 nm of Application Example 3, LCDU=3.2 nm, higher than the 1.7 nm of Application Example 3; after aging at 85℃ / 85%RH for 168 h, Tg decreases by 4.8℃, greater than the 1.7℃ of Application Example 3; after aging at 85℃ / 85%RH for 168 h, the water absorption rate is 0.85 wt%, higher than the 0.28 wt% of Application Example 3; the etching selectivity ratio (resin:SiO2) = 1:1.8, lower than the 1:3 of Application Example 3; the defect rate is 0.12 / cm. 2 This is higher than the 0.006 / cm in Application Example 3. 2 These data confirm that when the EO content exceeds the range of 70-75 mol%, thermal stability and graphic accuracy decrease significantly.

[0187] Comparative Application Example 6

[0188] The difference from Application Example 3 is that the photoresist solution prepared in Example 3 was replaced with the photoresist prepared in Comparative Example 5, and then a silicon wafer with a patterned structure was prepared according to the same process as in Application Example 3.

[0189] Testing revealed that the surface roughness Rq of the spin-coated film was 0.23 nm, which was worse than the 0.16 nm of Application Example 3. The internal stress was 28 MPa, higher than the 11 MPa of Application Example 3. The spontaneous crack density was 1.5 / cm. An exposure dose of 32 mJ / cm² was required. 2 The sensitivity was significantly reduced; the resolution was 18.8 nm, lower than the 15.9 nm of Application Example 3; the development expansion rate was 5.2%, higher than the 2.6% of Application Example 3; LWR=2.87 nm, higher than the 2.05 nm of Application Example 3; LCDU=3.0 nm, higher than the 1.7 nm of Application Example 3; the resist layer was prone to cracking during etching, and the linewidth loss was 1.8 nm, greater than the 0.7 nm of Application Example 3; the defect rate was 0.15 / cm. 2 This is higher than the 0.006 / cm in Application Example 3. 2 These data confirm that when the CL content exceeds the range of 25-30 mol%, sensitivity and development performance deteriorate, and increased brittleness leads to decreased process adaptability.

[0190] Taking Application Example 3 as an example, this application further incorporates ton-scale scale-up experiments and continuous evaluations to verify the effectiveness of the overall process of this application in actual production.

[0191] EOCL-72 was prepared in a 500L Harbin alloy autoclave (316L inner liner, electrolytically polished, Ra=0.1μm): THF 300L, KHMDS 525g, CL 22.6kg, EO 25.3kg, and process parameters were the same as in Example 3. DCS temperature control and online FT-IR closed-loop operation were used, achieving a monomer conversion rate ≥97%, yielding 91.2kg of EOCL resin, with a yield of 92%. GPC sampling of 20 samples showed: number-average molecular weight Mn=8100±90g / mol, K=1.17±0.02, total metal ion content ≤4ppm, and batch σ(Mn)=1.1%, meeting the requirements for continuous production. 200 kg of the resin was prepared using the same method as in Example 3. Online viscosity and particle size were monitored; viscosity fluctuation was ±0.05 cp, and particle size was ≤15 pcs / mL. After filtration, the resin was directly filled into a 500 mL stainless steel container under nitrogen protection. Exposure was then performed in the same manner as in Application Example 3, and the results were consistent with those of Application Example 3 (dose 20 ± 0.5 mJ / cm). 2 (LWR≤2.1nm) proves that the process is repeatable and stable.

[0192] Performance Results Summary

[0193] To more intuitively compare and analyze the effects of the photoresists prepared in the above embodiments and comparative examples, the applicant has recorded the key data of the above application examples and comparative application examples in Table 1.

[0194] Table 1 Key Data Table project Application Example 1 Application Example 2 Application Example 3 Comparative Application Example 1 Comparative Application Example 2 Comparative Application Example 3 Comparative Application Example 4 Comparative Application Example 5 Comparative Application Example 6 <![CDATA[Optimal dose / mJ / cm 2 > 18 22 20 35 35 / 28 16 32 Resolution / nm 15.8 16.0 15.9 22 22 / 18.5 19.2 18.8 Development swelling rate / % 2.8 2.5 2.6 8.5 8.5 / 2.9 3.8 5.2 LWR / nm 2.1 2.15 2.05 2.8 3.2 / 2.6 2.8 2.87 LCDU / nm 1.75 1.8 1.7 3.5 3.8 / 2.9 3.2 3.0 <![CDATA[Etch Selectivity / Resist: SiO2]]> 1:2.9 1:3.1 1:3 1:31.2 1:1.1 / 1:2.1 1:1.8 1:2 Aging ΔTg / ℃ 1.8 1.6 1.7 13 3 / 3.5 4.8 3.2 <![CDATA[Bridging defect / cm 2 > 0.007 0.005 0.006 0.18 0.25 / 0.08 0.12 0.15 Metal ions / ppb ≤3.5 ≤2.8 ≤4 8.2 38 12 15 8 9

[0195] As can be seen from Table 1, the extreme ultraviolet photoresist of this application is significantly superior to the comparative example in terms of sensitivity, resolution, LER, thermal stability, etching selectivity, and defect density. Its core advantage stems from the synergistic effect of the EO segment (hydrophilic channel, stress release) and the CL segment (high Tg, etching resistance). It can be directly introduced into the mass production of 2nm node EUV and can be extended to multiple patterning platforms such as electron beam and nanoimprint, which has significant economic and social benefits.

[0196] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A high-strength extreme ultraviolet photoresist, characterized in that, The extreme ultraviolet photoresist is a film-forming resin of ethylene oxide-caprolactam block copolymer, and the general structural formula of the ethylene oxide-caprolactam block copolymer is: (EO)x-(CL)y; Wherein, EO is ethylene oxide, CL is caprolactam, x=70-75mol%, y=25-30mol%, and its number-average molecular weight Mn=7800-10000g / mol, and molecular weight distribution Đ≤1.

20.

2. The high-strength extreme ultraviolet photoresist according to claim 1, characterized in that, The glass transition temperature Tg of the ethylene oxide-caprolactam block copolymer is ≥175℃, and E′@180℃ is ≥3.2GPa.

3. The high-strength extreme ultraviolet photoresist according to claim 2, characterized in that, The ethylene oxide-caprolactam block copolymer was prepared by the following method: S1. Under anhydrous and oxygen-free conditions and a temperature of -30~-10℃, caprolactam is subjected to ring-opening polymerization under the action of an initiator to obtain CL block; S2. Add ethylene oxide to the system in step S1, and then carry out a polymerization reaction at a temperature of -10~10℃ to obtain CL-EO diblock; S3. Add methanol to the system in step S2 to terminate the reaction, then precipitate, filter, and vacuum dry to obtain ethylene oxide-caprolactam block copolymer.

4. The high-strength extreme ultraviolet photoresist according to claim 1, characterized in that, The raw materials used in the extreme ultraviolet photoresist, by weight percentage, include the following components: 9-12% ethylene oxide-caprolactam block copolymer; Photoacid-producing agent: 0.15-0.25%; Crosslinking agent 0.1-0.15%; Additives 0.01-0.02%; Solvent balance.

5. The high-strength extreme ultraviolet photoresist according to claim 4, characterized in that, The extreme ultraviolet photoresist has a linear absorption coefficient of μ=0.28-0.38 / μm at an extreme ultraviolet light wavelength of 13.5nm.

6. The high-strength extreme ultraviolet photoresist according to claim 5, characterized in that, After the extreme ultraviolet photoresist is formed and aged for 168 hours at 85℃ / 85%RH, the Tg decrease is ≤2℃, the development expansion rate is ≤3%, the line width roughness LWR after development is ≤2.2nm, and the local critical size uniformity LCDU is ≤1.8nm.

7. A method for preparing a high-strength extreme ultraviolet photoresist according to any one of claims 1-6, characterized in that, Includes the following steps: I. Raw material pretreatment; II. Under the protection of an inert gas, the ethylene oxide-caprolactam block copolymer and solvent are mixed and heated and stirred until the ethylene oxide-caprolactam block copolymer is completely dissolved. Then, the photoacid generator, crosslinking agent and additives are added and stirred while maintaining the temperature to form a uniform and transparent mixture. III. Filter and degas to obtain high-strength extreme ultraviolet photoresist.

8. The application of a high-strength extreme ultraviolet photoresist in a patterning method, characterized in that, Includes the following steps: The extreme ultraviolet photoresist according to any one of claims 1-6 is spin-coated onto a substrate, then exposed under extreme ultraviolet light, and subsequently dried and developed to obtain a patterned structure.

9. The application of a high-strength extreme ultraviolet photoresist according to claim 8 in a patterning method, characterized in that, The exposure dose is 8-22 mJ / cm. 2 .

10. The application of a high-strength extreme ultraviolet photoresist according to claim 8 in a patterning method, characterized in that, The resolution of the patterned structure is ≤16nm, the aspect ratio is (1-4):1, and the sidewall angle is 86-90°.