Photoresist composition, method of preparing the same, and method of forming a photoresist pattern

Abstract

The present application relates to a photoresist composition, a preparation method thereof and a method for forming a photoresist pattern. The method for preparing the photoresist composition comprises the steps of mixing metal oxide nanoparticles, an azide photoinitiator and a solvent to obtain an intermediate mixture; adding an aqueous activator to the intermediate mixture and mixing to obtain the photoresist composition; wherein the aqueous activator is an aqueous solvent with polarity greater than or equal to water; and the addition percentage of the aqueous activator is 0.5-7.5wt% based on the total mass of the intermediate mixture. According to the method of the present application, the combination of metal oxide nanoparticles and azide photoinitiator, combined with the activation step, makes the prepared photoresist composition have excellent photosensitivity and imaging ability.

Description

Technical Field

[0001] This invention relates to the field of photolithography, specifically to a photoresist composition, its preparation method, and a method for forming photolithographic patterns. Background Technology

[0002] The ever-increasing integration density of large-scale integrated circuits demands ever smaller feature sizes, with current processing dimensions reaching the nanometer scale. The development of integrated circuits relies heavily on photolithography technology, and photoresist is the most critical basic material in this technology. Photoresist is a type of mixed material sensitive to light or radiation, typically composed of a photoresist substrate, photosensitizer, solvent, and other additives. When exposed to exposure sources such as ultraviolet light, electron beams, ion beams, excimer laser beams, and X-rays, the solubility and adhesion properties of photoresist change significantly, allowing it to be developed in a suitable solvent to form photolithographic patterns. Based on whether the photoresist is removed or retained, it can be divided into two main categories: positive photoresist and negative photoresist.

[0003] Photoresists mainly include chemically amplified resist (CAR), molecular glass (MG) resists, and metal oxide nanoparticle (MONP) resists. CARs induce acute changes in the material within the exposed area through a photoacid-catalyzed deprotection reaction, resulting in solubility differences. This mechanism significantly improves the quantum efficiency of CARs, giving them high sensitivity. However, the random diffusion of photoacids in the resist film causes blurring at the edges between exposed and unexposed areas, limiting further improvements in lithography resolution. Furthermore, as the size of pattern features continues to shrink, the size of the polymer molecular chains themselves has become increasingly significant (typically 6–12 nm), and the roughness caused by material size has become a bottleneck for high-resolution lithography. To address the size issue of polymer chains, researchers have proposed even smaller molecular glasses. MG resists mostly employ a chemical amplification mechanism, thus MG can be considered an extension of CAR. However, the pattern blurring caused by photoacid diffusion still exists, limiting the improvement in resolution offered by this technique. In recent years, MONP photoresists have become a research hotspot due to their high etch resistance, small size effect, and high resolution potential. MONP photoresists typically consist of a transition metal oxide core and an organic shell. The charge shielding effect provided by the organic ligands gives MONPs good solubility and film-forming properties; furthermore, MONPs have a much smaller individual size (1-4 nm) than polymers, and this small and uniform size is beneficial for improving imaging resolution. However, MONPs themselves are not photosensitive, therefore, photoinitiators are still required for patterning in deep ultraviolet lithography.

[0004] However, since Ober and Brainard pioneered MONP photoresists in 2009, the field has consistently used photoacid-based initiators similar to those used in CAR photoresists. Photoacids react with ligands on the MONP surface to induce a polarity change in the exposed region, thereby creating a solubility difference in the MONP photoresist during exposure and achieving photolithographic imaging. However, this approach of "using the previous generation of photoinitiators" is far from efficient. Therefore, finding specialized initiators and initiation systems, as well as preparation methods, suitable for high-resolution, high-sensitivity photoresists on metal substrates is a core challenge for further development in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a photoresist composition, a method for preparing the same, and a method for forming photolithographic patterns. Specifically, it provides a method for activating photoresist components to prepare a photoresist composition with high resolution and high sensitivity, as well as the photoresist composition obtained therefrom and a method for forming photolithographic patterns.

[0006] According to one aspect of the present invention, a method for preparing a photoresist composition is provided, comprising the steps of: Metal oxide nanoparticles, azide photoinitiator, and solvent are mixed to obtain an intermediate mixture; An aqueous activator is added to the intermediate mixture, and the mixture is then mixed to obtain the photoresist composition. The aqueous activator is an aqueous solvent with a polarity greater than or equal to that of water. Based on the total mass of the photoresist composition, the percentage of the aqueous activator added is 0.5~7.5wt%.

[0007] According to a preferred embodiment, when the percentage of aqueous activator added is 0.5 to 1.5 wt%, adding the aqueous activator to the intermediate mixture includes adding the aqueous activator itself directly to the intermediate mixture.

[0008] According to a preferred embodiment, when the percentage of aqueous activator added is greater than 1.5 wt% and less than 7.5 wt%, adding aqueous activator to the intermediate mixture includes pre-mixing the aqueous activator with at least a portion of the solvent to obtain an activated solvent, and then adding the activated solvent to the intermediate mixture.

[0009] According to a preferred embodiment, the aqueous activator is water.

[0010] According to a preferred embodiment, the mass ratio of the azide photoinitiator to the aqueous activator is (0.1~100):1.

[0011] According to a preferred embodiment, the mass ratio of the azide photoinitiator to the aqueous activator is (0.5~25):1.

[0012] According to a preferred embodiment, the metal oxide nanoparticles have the general formula Zr x Q y L n In this context, x and y are independent integers from 1 to 10, Q is one or both of O and OH, L is an organic ligand containing a double bond, and x:n = 1:(0.1~10).

[0013] According to a preferred embodiment, based on the total mass of the photoresist composition, the mass percentage of the metal oxide nanoparticles is 1 to 50 wt%, and the mass percentage of the azide photoinitiator is greater than 0 and less than or equal to 2.5 wt%.

[0014] According to a preferred embodiment, the azido photoinitiator is selected from 2,6-bis-(4-azidobenzyl)cyclohexanone, 2,6-di(4-azidobenzyl)-4-methylcyclohexanone, (1E,4E)-1,5-bis(4-azido-2,3,5,6-tetrafluorophenyl)pentyl-1,4-dien-3-one, ethane-1,2-diylbis(4-azido-2,3,5,6-tetrafluorobenzoate), and 4,4'-biphenyl dibenzyl azido. The solvent is selected from propylene glycol monomethyl ether acetate, toluene, dimethyl carbonate, N,N-dimethylformamide, and acetylacetone; and / or The organic ligands of the metal oxide nanoparticles are selected from acrylic acid, methacrylic acid and 3,3-dimethacrylic acid.

[0015] According to a preferred embodiment, the metal oxide nanoparticles are crystals with a particle size between 1 and 5 nm.

[0016] According to a preferred embodiment, the metal oxide nanoparticles are Zr6O4(OH)4(C4H5O2). 12 .

[0017] According to another aspect of the present invention, a photoresist composition is provided, prepared by the above method.

[0018] According to another aspect of the present invention, a method for forming a photolithographic pattern is provided, comprising the steps of: The above photoresist composition is coated onto a substrate to form a photoresist coating; The substrate having the photoresist coating is exposed under energy irradiation; The exposed substrate is developed using a developer.

[0019] According to a preferred embodiment, the energy irradiation is ultraviolet light with a wavelength of 245 nm or 365 nm, and the exposure dose is 14~42 mJ / cm².2 .

[0020] According to a preferred embodiment, the developer is selected from benzene, o-xylene, m-xylene, p-xylene, ethyl acetate, butyl acetate, ethanol, n-propanol, isopropanol, n-butanol, n-hexane, cyclohexane, and decahydronaphthalene.

[0021] According to a preferred embodiment, the method further includes a pre-baking step of the substrate after the coating step, preferably pre-baking at 60~120°C for 0.5~1.5 min.

[0022] According to another preferred embodiment, the method further includes a post-baking step of the substrate after the exposure step, preferably at 90~120°C for 1~4 min.

[0023] The method for preparing photoresist compositions according to the present invention utilizes the combination of metal oxide nanoparticles and azide photoinitiators, as well as the activation effect of an aqueous activator on the system, to obtain photoresist compositions with improved photosensitivity and higher pattern shape resolution, thereby achieving photolithographic patterns with smaller linewidths at a smaller exposure dose. Attached Figure Description

[0024] Figures 1 to 3 The photoresist sample prepared by Comparative Example 1, which is an indirect mixture of 0.5 wt% A2 and 0.5 wt% H2O, is shown. The photoresist was prepared at an exposure dose of 14 mJ / cm². 2 28 mJ / cm 2 42 mJ / cm 2 The photolithographic patterns were obtained under a combination of post-baking conditions of 100℃ for 1 min, 100℃ for 2 min, 100℃ for 3 min, and 100℃ for 4 min.

[0025] Figures 4 to 6 The image shows a photoresist sample prepared according to Example 1 of the present invention, which is a direct mixture of 0.5 wt% A2 and 0.5 wt% H2O, and is subjected to an exposure dose of 14 mJ / cm. 2 28 mJ / cm 2 42 mJ / cm 2 The photolithographic pattern under the combined conditions of 100℃ for 1 min, 100℃ for 2 min, and 100℃ for 3 min.

[0026] Figure 7 Line graphs showing the linewidth variation of a photoresist sample prepared according to Example 1 of the present invention, which is a direct mixture of 0.5 wt% A2 and 0.5 wt% H2O, under different combinations of exposure doses and post-baking conditions are shown.

[0027] Figure 8Line graphs showing the linewidth variation of a photoresist sample prepared according to Comparative Example 1, which is indirectly mixed with 0.5 wt% A2 and 0.5 wt% H2O, under different combinations of exposure doses and post-baking conditions are shown.

[0028] Figure 9 A comparative bar chart showing the exposure sensitivity of photoresist samples prepared according to Example 1 and Comparative Example 1 is presented.

[0029] Figures 10 to 12 The photolithographic patterns of a photoresist sample prepared according to Comparative Example 2, which is indirectly mixed with 0.5 wt% A2 and 1.5 wt% H2O, are shown under different combinations of exposure doses and post-baking conditions.

[0030] Figure 13 The linewidth variation of the photoresist sample indirectly mixed with 0.5 wt% A2 and 1.5 wt% H2O according to Example 2 is shown under different exposure doses and post-baking times.

[0031] Figure 14 This is a comparison of the effects of 0.5 wt% H2O and 1.5 wt% H2O water content on the sensitivity of the photoresist prepared according to Example 2.

[0032] Figure 15 It shows 28 mJ / cm 2 The effects of water, proton solvents and polar aprotic solvents on the sensitivity of the A2 system under different dosages.

[0033] Figure 16 The dissolved state of the photoresist prepared according to the composition shown in Table 1 is shown.

[0034] Figure 17 It shows 15.2 mJ / cm 2 The effect of different water concentrations at different dosages on the sensitivity of the A2 system. Detailed Implementation

[0035] To facilitate understanding of the present invention, the various methods of the present invention will be described more fully below. Preferred embodiments of the present invention are given herein, but the present invention is not limited to these described embodiments and can be implemented in various different forms.

[0036] Unless otherwise defined, the terminology used herein has the same technical meaning as commonly understood by those skilled in the art, and is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0037] Method for preparing photoresist compositions The method for preparing a photoresist composition according to the present invention includes a mixing step and an activation step.

[0038] Specifically, the above mixing step may include mixing metal oxide nanoparticles, azide photoinitiator and solvent to obtain an intermediate mixture.

[0039] Among them, the above-mentioned metal oxide nanoparticles have the general formula Zr x Q y L n In this context, x and y can be independent integers from 1 to 10, for example, 2, 3, 4 or 5; Q is one or both of O and OH, and L can be an organic ligand containing a double bond, which can be an acrylic compound, further selected from one or more of methacrylic acid, acrylic acid and 3,3-dimethacrylic acid, preferably one or both of acrylic acid and methacrylic acid.

[0040] Furthermore, in the above-mentioned metal oxide nanoparticles, x:n = 1:(0.1~10), preferably 1:(0.5~8), more preferably 1:(1~6), for example 1:2, 1:3, 1:4 or 1:5.

[0041] The aforementioned metal oxide nanoparticles are crystals with a core-shell structure, wherein zirconium oxide particles are located at the core, and acrylic ligands coat the zirconium oxide particles around the core. The particle size of these metal oxide nanoparticles can be between 1 and 5 nm, for example, 3 nm.

[0042] Specifically, the aforementioned metal oxide nanoparticles can be Zr6O4(OH)4(C4H5O2). 12 Its abbreviation is Zr6O4(OH)4(MAA). 12 MAA is methacrylic acid.

[0043] According to one embodiment, based on the total mass of the photoresist composition, the mass percentage of metal oxide nanoparticles can be 1 to 50 wt%, preferably 3 to 45 wt%, more preferably 5 to 42 wt%, for example 8 to 38 wt%, specifically 10 wt%, 13 wt%, 15 wt%, 18 wt%, 20 wt%, 23 wt%, 25 wt%, 27 wt%, 30 wt%, 33 wt%, or 36 wt%.

[0044] According to another embodiment, the above-mentioned azido photoinitiator may be selected from 2,6-bis-(4-azidobenzyl)cyclohexanone, 2,6-bis(4-azidobenzyl)-4-methylcyclohexanone, (1E,4E)-1,5-bis(4-azido-2,3,5,6-tetrafluorophenyl)pentyl-1,4-dien-3-one, ethane-1,2-diylbis(4-azido-2,3,5,6-tetrafluorobenzoate), and 4,4'-biphenyl dibenzyl azido, preferably 2,6-bis(4-azidobenzyl)-4-methylcyclohexanone.

[0045] Based on the total mass of the photoresist composition, the mass percentage of the aforementioned azide photoinitiator can be greater than 0 and less than or equal to 2.5 wt%, preferably 0.5 to 2 wt%, more preferably 1 to 1.5 wt%, for example 1.2 wt%.

[0046] According to yet another embodiment, the solvent may be selected from propylene glycol monomethyl ether acetate (PGMEA), toluene, dimethyl carbonate, N,N-dimethylformamide, and acetylacetone, for example, propylene glycol monomethyl ether acetate or toluene.

[0047] The mixing method described above can employ conventional mixing techniques in the art, such as magnetic stirring, mechanical stirring, or ultrasonic mixing. This mixing method allows the metal oxide nanoparticles and photoinitiator to be uniformly dispersed in the solvent, forming a homogeneous intermediate mixture.

[0048] The activation step described above may include adding an aqueous activator to the intermediate mixture obtained above, and mixing to obtain a photoresist composition. The aqueous activator may be added directly to the intermediate mixture, or the aqueous activator may be pre-mixed with at least a portion of a solvent to obtain an activation solvent, and then the activation solvent may be added to the intermediate mixture. Pre-mixing the aqueous activator with at least a portion of the solvent may involve mixing the aqueous activator with one or more components of the solvent, or mixing it with a portion of one or more components of the solvent.

[0049] Specifically, when the percentage of aqueous activator added is 0.5~1.5wt%, adding aqueous activator to the intermediate mixture includes directly adding the aqueous activator itself to the intermediate mixture; when the percentage of aqueous activator added is greater than 1.5wt% and less than 7.5wt%, adding aqueous activator to the intermediate mixture includes pre-mixing the aqueous activator with at least a portion of the solvent to obtain an activated solvent, and then adding the activated solvent to the intermediate mixture.

[0050] According to one embodiment, the aqueous activator described above may be an aqueous solvent with a polarity greater than or equal to that of water; preferably water. Based on the total mass of the photoresist composition, the percentage of the aqueous activator added is 0.5 to 7.5 wt%, preferably 1 to 7 wt%, more preferably 2 to 6 wt%, for example 3 wt%, 4 wt%, or 5 wt%.

[0051] The above-mentioned method for preparing photoresist compositions utilizes the reaction between an aqueous activator (especially water) and an azide photoinitiator, which greatly improves the sensitivity of the photoresist composition and thus enables better photolithographic pattern quality.

[0052] Photoresist composition According to another embodiment of the present invention, a photoresist composition is provided, which is prepared by the above method.

[0053] Specifically, the photoresist composition of the present invention may comprise metal oxide nanoparticles, an azide photoinitiator, an aqueous activator, and a solvent. Depending on different process requirements, the photoresist composition of the present invention may also comprise one or more other functional additives, such as leveling agents, thickeners, and stabilizers; preferably, the photoresist composition of the present invention may consist of metal oxide nanoparticles, a photoinitiator, an aqueous activator, and a solvent.

[0054] According to one embodiment, the above-mentioned photoresist composition may comprise 1-50 wt% metal oxide nanoparticles, 2.5 wt% or less but not zero photoinitiator, 0.5-7 wt% aqueous activator, optional appropriate amounts of other functional additives, and the balance being solvent. Preferably, the above-mentioned photoresist composition may consist of 1-50 wt% metal oxide nanoparticles, 2.5 wt% or less but not zero photoinitiator, 0.5-7 wt% aqueous activator, and the balance being solvent.

[0055] The aforementioned metal oxide nanoparticles have the general formula Zr x Q y L n Where Q is one or both of O and OH, x and y can independently be integers from 1 to 10, for example, 2, 3, 4, 5, 6, 7, 8 or 9; and x:n = 1:(0.1~10), preferably 1:(0.5~8), more preferably 1:(1~6), for example 1:2, 1:3, 1:4 or 1:5. For example, the metal oxide nanoparticles can be Zr6O4(OH)4(C4H5O2). 12 .

[0056] Furthermore, L in the above-mentioned metal oxide nanoparticle structure can be an organic ligand containing a double bond, such as an acrylic acid compound, and can be selected from one or more of methacrylic acid, acrylic acid and 3,3-dimethacrylic acid, preferably one or two of acrylic acid and methacrylic acid.

[0057] The particle size of these metal oxide nanoparticles can be between 1 and 5 nm, for example, 3 nm.

[0058] The aforementioned azido photoinitiator can be selected from 2,6-bis-(4-azidobenzyl)cyclohexanone, 2,6-bis(4-azidobenzyl)-4-methylcyclohexanone, (1E,4E)-1,5-bis(4-azido-2,3,5,6-tetrafluorophenyl)pentyl-1,4-dien-3-one, ethane-1,2-diylbis(4-azido-2,3,5,6-tetrafluorobenzoate), and 4,4'-biphenyl dibenzyl azido, preferably 2,6-bis(4-azidobenzyl)-4-methylcyclohexanone.

[0059] The aforementioned aqueous activator can be an aqueous solvent with a polarity greater than or equal to that of water, preferably an aqueous solvent capable of reacting with azide photoinitiators, and more preferably water. Based on the total mass of the photoresist composition, the percentage of aqueous activator added is 0.5–7.5 wt%, preferably 1–7 wt%, more preferably 2–6 wt%, for example 3 wt%, 4 wt%, or 5 wt%. When the amount of aqueous activator added is less than 0.5 wt%, an effective activation effect cannot be produced. When the amount of aqueous activator added is greater than 7.5 wt%, it will lead to the precipitation of metal oxide nanoparticles, and the uniformity of the photoresist composition will deteriorate, resulting in poor photolithographic pattern effects. When the amount of aqueous activator added is within the range of 0.5–7.5 wt%, as the amount of aqueous activator added increases, the sensitivity of the photoresist composition also increases accordingly, and even the post-baking process can be omitted, resulting in improved contrast of the obtained photolithographic pattern.

[0060] The solvents mentioned above are selected from propylene glycol monomethyl ether acetate, toluene, dimethyl carbonate, N,N-dimethylformamide and acetylacetone, with propylene glycol monomethyl ether acetate being preferred.

[0061] The stabilizers that may be included in the above photoresist composition may be selected from isoamyl alcohol, n-hexanol, glycerol and n-hexane to improve the chemical stability of the photoresist composition and prevent light, heat or decomposition reactions during storage or transportation.

[0062] The thickeners that may be included in the above photoresist composition may be selected from hydroxymethyl cellulose, sodium alginate, hydroxymethyl, hydroxyethyl cellulose ether, chitosan, polyacrylamide, etc.

[0063] The above-mentioned photoresist composition is preferably prepared by the method described above for preparing photoresist compositions, and can be used in a variety of photolithography techniques, especially suitable for ultraviolet photolithography techniques, such as 245 nm ultraviolet photolithography, 365 nm ultraviolet photolithography, etc., and has excellent sensitivity and resolution in this photolithography technique.

[0064] Methods for forming photolithographic patterns According to another embodiment of the present invention, a method for forming a photolithographic pattern is provided, comprising a coating step, an exposure step, and a development step. Optionally, the method for forming a photolithographic pattern may further include a pre-baking step after the coating step and a post-baking step after the development step.

[0065] The coating step described above includes coating the photoresist composition onto a substrate to form a photoresist coating. This coating step can be performed using conventional coating methods in the art, such as spin coating, roll coating, dip coating, or slot coating. The substrate can be a conventional substrate material in the field of photolithography, such as a silicon wafer, a quartz wafer, or a glass sheet. According to a preferred embodiment, before performing the coating step, the method of the present invention can further filter the photoresist composition, for example, using a filter with a pore size of 0.22 μm, to remove large particles from the photoresist composition.

[0066] According to one embodiment, after the above coating step, the method for forming a photolithographic pattern may further include a pre-baking step, which includes drying the substrate with the photoresist coating at a temperature of 60~120°C, preferably 90~110°C (e.g., 100°C), for example, by placing it on a hot plate to dry for 0.5~1.5 min (preferably 1 min).

[0067] The above exposure step may include exposing the substrate having the photoresist coating under energy irradiation. This energy irradiation may be 245 nm ultraviolet light, 365 nm ultraviolet light, or an electron beam, preferably 245 nm ultraviolet light. The exposure dose may be 14~45 mJ / cm². 2 The preferred value is 15~42 mJ / cm. 2 For example, 18 mJ / cm 2 20 mJ / cm 2 22 mJ / cm 2 25 mJ / cm 2 28 mJ / cm 2 30 mJ / cm 2 32 mJ / cm 2 35 mJ / cm 2 38 mJ / cm 2 or 40 mJ / cm 2 On the other hand, when using 245nm ultraviolet lithography, the exposure power can be 1~1.6 mW / cm². 2 For example, 1.2~1.4 mW / cm 2 The exposure time can be 8 to 45 seconds, preferably 12 to 40 seconds, such as 15 seconds, 18 seconds, 20 seconds, 25 seconds, 30 seconds or 35 seconds.

[0068] According to another embodiment, after the exposure step described above, the method for forming the photolithographic pattern may further include a post-baking step, which involves post-baking the exposed substrate at a temperature of 90~120°C, preferably 95~110°C (e.g., 100°C), to allow the curing reaction of the exposed photoresist composition to proceed more completely. The post-baking time may be 1~4 minutes.

[0069] In the metal oxide nanoparticle-azide photoinitiator system of this invention, the azide photoinitiator molecules, upon exposure to light, generate nitride active species, which react with ligands on the surface of the metal oxide nanoparticles. Although this initiator has a low reaction threshold, meaning that active species can be generated even with a small exposure dose, its addition reaction rate with double bonds is slow. Therefore, immediate development after exposure often results in missing tops of the photolithographic pattern, while allowing it to stand for a period of time to allow for sufficient reaction, or using a post-baking process to accelerate the reaction, is beneficial for preserving the pattern intact. However, the standing time is relatively long, and the coating is easily contaminated by particulate matter during the standing process. Therefore, a more efficient and less contamination-risk post-baking method is preferred to promote the polymerization reaction of the photoresist composition.

[0070] The above-mentioned development step may include developing the exposed substrate with a developer. Specifically, the developer may be selected from benzene, o-xylene, m-xylene, p-xylene, ethyl acetate, butyl acetate, ethanol, n-propanol, isopropanol, n-butanol, n-hexane, cyclohexane, and decahydronaphthalene.

[0071] The above-mentioned method for forming photolithographic patterns combines a metal oxide nanoparticle-azide photoinitiator system with a preparation method including activation treatment, resulting in photolithographic patterns with complete patterns, significantly improved contrast and resolution.

[0072] According to a specific embodiment of the present invention, the photoresist composition is prepared as follows: (1) Components and preparation of photoresist composition Weigh out an appropriate amount of metal oxide nanoparticles (with the general molecular formula Zr). x Q y L nWhere x and y are integers from 1 to 10, x:n = 1:(0.1~10), Q is one or both of O and OH, L is an organic ligand containing a double bond, including acrylic acid and methacrylic acid, etc.), azido photoinitiators (including 2,6-bis-(4-azidobenzyl)cyclohexanone, 2,6-di(4-azidobenzyl)-4-methylcyclohexanone, (1E,4E)-1,5-bis(4-azido-2,3,5,6-tetrafluorophenyl)pentyl-1,4-dien-3-one, ethane-1,2-diylbis(4-azido-2,3,5,6-tetrafluorobenzoate), 4,4'-biphenyl dibenzyl azido, etc.), and solvents (propylene glycol monomethyl ether acetate, toluene, dimethyl carbonate, N,N-dimethylformamide, acetylacetone, etc.) in a certain proportion (where Zr x Q y L n A photoresist composition was prepared by mixing a certain amount of deionized water (0.5-7.5 wt%) in the composition at a mass percentage of 1-50 wt% and an azide photoinitiator at a mass percentage greater than 0 and less than or equal to 2.5 wt%. After thorough mixing, a certain amount of deionized water was added to the mixture, and the mixture was shaken again to obtain the photoresist composition.

[0073] (2) Formation of photolithographic patterns (2.1) Spin coating and pre-baking Take an appropriate amount of photoresist composition and spin coat it onto the silicon wafer surface at a certain speed (e.g., 500~5000 r / min). Pre-bake (temperature 60~120℃) for 30s to remove the solvent.

[0074] (2.2) Exposure Exposure was performed using a photolithography machine. Exposure conditions included 245 nm ultraviolet light and an exposure dose of 14–45 mJ / cm². 2 .

[0075] (2.3) Post-baking The exposed silicon wafer was heated on a hot plate at 100°C for 2 minutes.

[0076] (2.4) Development The post-baked silicon wafer is developed in a developer (selected from one or more of benzene, o-xylene, m-xylene, p-xylene, ethyl acetate, butyl acetate, ethanol, n-propanol, isopropanol, n-butanol, n-hexane, cyclohexane, decahydronaphthalene, etc.) for 10-30 seconds. After development, the substrate is dried and the photolithography imaging results are observed.

[0077] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but is not limited to the following embodiments. Those skilled in the art can propose other embodiments within the technical framework of the present invention, but these embodiments are all included within the protection scope of the present invention.

[0078] Example I. The impact of direct and indirect mixing methods on sensitivity Comparative Example 1 0.5 wt% 2,6-bis(4-azidobenzyl)-4-methylcyclohexanone (hereinafter referred to as A2) was indirectly mixed with 0.5 wt% H2O. Preparation of photoresist composition: Take 0.25g of Zr6O4(OH)4(MAA) metal oxide nanoparticles with an average particle size of 1~5nm. 12 0.025 g of 2,6-bis(4-azidobenzyl)-4-methylcyclohexanone A2 (0.5 wt%) was mixed with 3.7 g of toluene solvent to obtain an intermediate mixture. 0.025 g of deionized water (0.5 wt%) was added to 1 g of toluene and shaken thoroughly. A toluene-water activator was added to the intermediate mixture and shaken thoroughly to obtain a photoresist composition. The photoresist composition was filtered through a 0.22 μm filter. An appropriate amount of the filtered photoresist composition was dropped onto the silicon wafer surface and homogenized at 2000 r / min for 1 minute. The solvent was dried at 100 °C for 1 minute. Exposure was performed under a 254 nm mercury lamp light source (the mask linewidth gradually increased from the inside to the outside, with the outermost linewidth being 10 μm), with an exposure dose of 14 mJ / cm². 2 28mJ / cm 2 42 mJ / cm 2 The exposed silicon wafers underwent post-baking treatments at 100℃ for 1 min, 100℃ for 2 min, 100℃ for 3 min, and 100℃ for 4 min. Subsequently, they were developed in 1,2-propanediol diacetate for 10 s. After drying the surface developer with an air gun, the photolithographic pattern was observed using an optical microscope (100x magnification). The results are as follows. Figures 1 to 3 As shown, the line width changes as follows Figure 8 As shown (measure the outermost line width, corresponding to a 10 μm dimension line on the mask).

[0079] Figure 1 This indicates that under the indirect mixing process, a low exposure dose of 14 mJ / cm² is achieved. 2No photolithographic pattern was observed after a post-baking time of 100℃ for 1 min; however, patterns could be formed under extended post-baking times (100℃ for 2 min, 100℃ for 3 min, and 100℃ for 4 min), but the pattern resolution was poor (significant top defects) and the linewidth was low (7.88 μm) at 2 min, requiring longer post-baking times (3 min and 4 min) to improve, with linewidths of 8.32 μm and 8.76 μm, respectively. Figure 1 compared to, Figure 2 This shows that when the exposure dose is increased to 28 mJ / cm 2 At the same time, photolithographic patterns can be formed under different post-baking times, and the pattern resolution is higher and the linewidth is larger as the post-baking time is extended. Figure 3 It is shown that, under the indirect mixing process, even at 42 mJ / cm 2 At higher exposure doses, without a post-baking step, photolithographic patterns cannot be formed, whereas... Figure 2 In contrast, under the same post-baking conditions, increasing the exposure dose resulted in a comparable linewidth for the lithographic pattern, with no significant improvement in resolution. This demonstrates that the indirect mixing process has lower sensitivity and a slower reaction rate, consistent with the slow reaction rate of azido-double bond addition in existing technologies.

[0080] Example 1 0.5 wt% A2 and 0.5 wt% H2O were directly mixed. Preparation of photoresist composition: Take 0.25g of Zr6O4(OH)4(MAA) metal oxide nanoparticles with an average particle size of 1~5nm. 12 0.025 g of 2,6-bis(4-azidobenzyl)-4-methylcyclohexanone (0.5 wt%) and 4.7 g of toluene solvent were mixed to obtain an intermediate mixture. 0.025 g of deionized water (0.5 wt%) was added to the intermediate mixture and shaken thoroughly to obtain a photoresist composition. The photoresist composition was filtered through a 0.22 μm filter. An appropriate amount of the filtered photoresist composition was dropped onto the silicon wafer surface and homogenized at 2000 r / min for 1 minute. The solvent was dried at 100 °C for 1 minute. Exposure was performed under a 254 nm mercury lamp light source (outermost linewidth of the mask was 10 μm) with an exposure dose of 14 mJ / cm². 2 28 mJ / cm 2 42 mJ / cm 2 The exposed silicon wafers underwent post-baking treatments at 100℃ for 1 min, 100℃ for 2 min, and 100℃ for 3 min. Subsequently, they were developed in 1,2-propanediol diacetate for 10 s. After drying the surface developer with an air gun, the photolithographic pattern was observed using an optical microscope (100x magnification). The results are as follows: Figures 4 to 6 As shown, the line width changes as follows Figure 7 As shown.

[0081] and Figures 1 to 3 (Comparative Example 1) In comparison, under the same exposure and post-bake conditions, Figures 4 to 6 (Example 1) The direct mixing process results in more complete lithographic patterns, significantly improves the top-end missing pattern problem, and achieves clear patterns with shorter post-baking times (e.g., 1 min) and significantly improved resolution with longer post-baking times (e.g., 3 min). This demonstrates that the direct mixing process can improve reaction efficiency and enhance sensitivity.

[0082] contrast Figure 7 and Figure 8 , Figure 7 (Example 1) shows a more pronounced change in linewidth, especially with a faster increase in linewidth at low exposure doses. Figure 8 (Comparative Example 1) shows that the linewidth changes little with exposure dose and post-bake time, indicating slow pattern formation. This demonstrates that the direct mixing process according to Example 1 can produce a larger linewidth variation under the same conditions, indicating that the photoresist according to Example 1 has higher sensitivity. This verifies that direct mixing can accelerate the reaction between nitride and the nanoparticle surface, solving the problem of slow reaction rate in the prior art.

[0083] Figure 9 The sensitivity of the two mixing processes (typically expressed as the exposure dose-linewidth variation) is compared using a bar chart. The sensitivity curve for the direct mixing process according to Example 1 is steeper, indicating that the target linewidth can be achieved at a lower exposure dose. This demonstrates that the direct mixing process can significantly improve the sensitivity of the photoresist, which is key to achieving high-resolution lithography in this invention.

[0084] II. Effect of Aqueous Activator Dosage If the content of the aqueous activator (e.g., water) is high, for example, if the mass percentage of the aqueous activator added is higher than 1.5 wt%, care should be taken to use an indirect mixing method to mix it with the intermediate mixture. If a large amount of aqueous activator (e.g., water) is added directly to the intermediate mixture, it may cause the photoresist composition to deactivate rapidly and lose its photosensitivity and imaging capabilities.

[0085] Example 2 0.5 wt% A2 and 1.5 wt% H2O were indirectly mixed. To prepare the photoresist solution, take 0.25 g of Zr6O4(OH)4(MAA) metal oxide nanoparticles. 120.025 g of 2,6-bis(4-azidobenzyl)-4-methylcyclohexanone (0.5 wt%) was mixed with 3.65 g of toluene solvent to obtain an intermediate mixture. 0.075 g of deionized water (1.5 wt%) was added to 1 g of toluene and thoroughly mixed to obtain a toluene-water aqueous activator. The toluene-water aqueous activator was added to the intermediate mixture and thoroughly mixed to obtain a photoresist, which was filtered through a 0.22 μm filter. An appropriate amount of the filtered photoresist was dropped onto the silicon wafer surface and homogenized at 2000 r / min for 1 minute. The solvent was dried at 100 °C for 1 minute. Exposure was performed under a 254 nm mercury lamp light source with an exposure dose of 14 mJ / cm². 2 28 mJ / cm 2 42 mJ / cm 2 The exposed silicon wafers underwent post-baking treatments at 100 °C for 1 min, 100 °C for 2 min, 100 °C for 3 min, and 100 °C for 4 min. Subsequently, they were developed in 1,2-propanediol diacetate for 10 s. After drying the surface developer with an air gun, the photolithographic pattern was observed, and the results are as follows. Figures 10 to 12 As shown, the linewidth-exposure dose variation is as follows: Figure 13 and Figure 14 As shown (the outermost line width of the mask is 10 μm).

[0086] Figures 10 to 12 The photolithographic pattern of the photoresist sample prepared by the indirect mixing process of 0.5 wt% A2 and 1.5 wt% H2O is shown, demonstrating the photolithographic pattern of the indirect mixing process at a high water content (1.5 wt%). The pattern exhibits higher contrast and more stable linewidth, indicating that a higher water content can further improve sensitivity, but indirect mixing is necessary to avoid photoresist deactivation. This demonstrates that when the content of the water-based activator increases to above 1.5 wt%, it must be used in conjunction with the process.

[0087] Figure 13 The image shows the linewidth variation of photoresist prepared using a high-water-content time-in-time mixing process, revealing that the linewidth variation is more significant with increasing exposure dose and post-baking time. A comparison shows that the linewidth variation is greater at a water content of 1.5 wt%, indicating higher sensitivity. This demonstrates that appropriately increasing the water content can activate the azide system, but the mixing method must be controlled.

[0088] Figure 14 The effect of different water contents on photoresist sensitivity is shown, particularly comparing the sensitivity curves at 0.5 wt% and 1.5 wt% water contents. Figure 14 It can be seen that the sensitivity is higher (the curve is steeper) at a water content of 1.5 wt%, proving that increasing the water content within a certain range can enhance the activation effect. However, excessive water content may lead to inactivation, so the water content needs to be precisely controlled.

[0089] III. The Influence of Different Water-Based Activators To investigate the effect of aqueous activators on azide sensitivity, the effects of protic solvents and polar aprotic solvents on the sensitivity of the azide initiation system were compared. Water is a polar protic solvent, and different solvents were used as aqueous activators in the following examples.

[0090] Example 3 By introducing azide A2-metal oxide nanoparticles Zr6O4(OH)4(MAA) 12 0.5 wt% solvent (water, methyl methacrylate (MAA), and methanol as protic solvents, and acetonitrile, acetone, tetrahydrofuran (THF), and propylene glycol monomethyl ether acetate (PGMEA) as polar aprotic solvents) was added to the photoresist, and then a 254 nm mercury lamp light source was used at 28 mJ / cm². 2 Exposure, baking, and development were performed at the specified dosage. The results are as follows: Figure 15 As shown.

[0091] Depend on Figure 15 It can be seen that pure A2 solvent at 28 mJ / cm 2 At the given dosage, almost no pattern could be obtained, but the addition of 0.5 wt% H2O significantly improved the sensitivity and produced good pattern quality. However, other protic and non-protic solvents had almost no effect on the A2 sensitivity. This indicates that the activation effect of water on azide comes from the reaction between azide and water, rather than a simple polarity effect.

[0092] Example 4 0.5 wt% A2 and x wt% H2O (x is 0.38~10) are directly mixed. Prepare the photoresist solution according to the amounts of each component shown in Table 1: Take 0.25 g of metal oxide nanoparticles Zr6O4(OH)4(MAA). 12 0.025 g of 2,6-bis(4-azidobenzyl)-4-methylcyclohexanone was mixed with solvent PGMEA. After complete mixing, an intermediate mixture was obtained. Deionized water was added to the intermediate mixture, and the mixture was shaken to obtain the photoresist. The solution states of the various photoresist samples are as follows. Figure 16 As shown.

[0093] The photoresist was filtered using a 0.22 μm pore size filter. An appropriate amount of the filtered photoresist was dropped onto the silicon wafer surface and homogenized at 2000 r / min for 1 minute. The solvent was dried at 100℃ for 1 minute. Exposure was then performed under a 254 nm mercury lamp light source with an exposure dose of 15.2 mJ / cm². 2After exposure, one portion of the silicon wafer was left unbaked, while another portion was baked at 100°C for 1 minute. Subsequently, it was developed in 1,2-propanediol diacetate for 10 seconds. After drying the surface developer with an air gun, the photolithographic pattern was observed, and the results are as follows. Figure 16 As shown.

[0094] Depend on Figure 16 It can be seen that as the amount of water added increases, the photoresist solution changes from clear to cloudy, especially when the amount of water added reaches 7.5wt% and 10wt%, the turbidity of the photoresist solution intensifies.

[0095] Depend on Figure 17 It can be seen that the sample without water and the sample with only 0.38wt% water showed no pattern after exposure without post-baking, and the pattern contrast after post-baking was extremely poor, indicating that adding a very small amount of water cannot activate the photoresist system.

[0096] Photolithographic patterns can be obtained by adding 0.5 wt% water to the sample without post-baking, but the contrast is also very poor. However, the contrast is significantly improved after post-baking, indicating that adding 0.5 wt% water has an activation effect on the system and slightly improves the sensitivity.

[0097] As the concentration of added water increases, the contrast of samples with 2.5 wt% or more of water is high after exposure and post-baking, indicating that the sensitivity of the reaction system is greatly improved; samples with 5 wt% or more of water can obtain high-contrast images without post-baking after exposure, indicating that the sensitivity of the reaction system is improved compared with the 2.5 wt% and 3.5 wt% samples.

[0098] When the water content is increased to 7.5 wt% or higher, the solution becomes turbid, indicating that nanoparticles have precipitated. At this point, the uniformity of the film after spin coating of the photoresist solution is poor, there are many surface impurities, the film thickness is uneven, and the pattern effect after exposure is poor and it cannot be used.

[0099] In summary, there is no activation effect when the water content is below 0.5 wt%, and the photoresist solution becomes cloudy and unusable when it is above 7.5 wt%. Therefore, the concentration range of added water should be (0.5~7.5 wt%), and adding 5 wt% water results in a higher degree of activation.

[0100] Table 1 Rubber Compound Components

[0101] In summary, the method for preparing the photoresist composition of the present invention has the following advantages: Aqueous activators (such as water) have an activating effect on the metal oxide nanoparticle-azide photoinitiator system. That is, aqueous activators can specifically improve the sensitivity of photoresists containing the azide photoinitiator-metal oxide nanoparticle system, which cannot be replaced by other solvents. Direct mixing is more efficient than indirect mixing, but indirect mixing is necessary for high water content to avoid deactivation.

[0102] The content of the aqueous activator needs to be controlled between 0.5 and 7.5 wt%, with an optimal value of 5 wt%. Too low a concentration will have no effect, while too high a concentration will lead to failure. Activation treatment accelerates the reaction between nitrogen carbene and the surface of metal oxide nanoparticles, solving the problems of slow reaction rate and missing tops of patterns in existing technologies.

[0103] Mechanism Explanation The photoresist composition of the present invention utilizes the interaction of metal oxide nanoparticles, an azide photoinitiator, and an aqueous activator to achieve enhanced sensitivity and improved pattern resolution. The mechanism is presumed to involve a reaction between the azide photoinitiator and the aqueous activator. Specifically, the azide photoinitiator generates nitrides. Nitrides are classified into singlet states (Ph...) based on their electron spin states. 1 N) and triplet state (Ph 3 N) two types. Among them, Ph 1 N is favorable for the addition of double bonds in organic ligands contained in metal oxide nanoparticles, Ph 1 Nitrogen (N) possesses an empty p orbital and a lone pair of electrons, exhibiting a dual reactivity similar to that of an electrophilic carbene: the π electrons of the double bond can donate electrons to its empty p orbital, while the lone pair of electrons in the nitrogen atom can form a new σ bond with the carbon atom in the double bond, thus achieving a concerted, symmetry-allowed [2+1] cycloaddition process. This reaction typically has a very low energy barrier, does not require spin flipping, and does not involve multiple intermediate steps. Ph... 3 The addition of N to the double bond is spin-forbidden, Ph 3 The two unpaired electrons of N occupy orthogonal orbitals, requiring a high-energy spin flip before they can form a closed-shell product with the singlet-state alkene. Therefore, Ph 3 The addition of N to the double bond is spin-selectively forbidden, requiring the reaction to overcome a higher transition state barrier, which is kinetically extremely unfavorable. Therefore, Ph 1 N is the core species that crosslinks with photoresist compositions containing metal oxide nanoparticles.

[0104] However, Ph 1 Nitrogen (N) itself is highly reactive, exhibiting numerous side reactions that compete with double bond addition, such as Ph... 1 Inter-N series leap to Ph 3 N, or Ph 1 N-vibrational relaxation leads to rearrangement reactions that generate benzo[a]azacyclopropane or enone imine. None of these three byproducts can react with double bonds to achieve crosslinking with metal oxide nanoparticles.

[0105] In addition, Ph 1N can undergo protonation. Aqueous activators (e.g., water) react with Ph... 1 The N reaction is particularly fast, with a protonation rate of 10. 9 s -1 This is on the order of magnitude faster than the rates of intersystem crossing and rearrangement reactions. Therefore, in systems containing aqueous activators (such as water), the photolysis-generated Ph... 1 N will be rapidly protonated to form nitride ions (PhNH4). + PhNH + It is highly electrophilic and more susceptible to nucleophilic attack by surrounding aqueous activators (such as water) to generate N-hydroxy aromatic amines (Ph-NHOH). Subsequently, under the action of aqueous activators (such as water), it undergoes further proton transfer and rearrangement, which can be converted into more stable aromatic amines (Ph-NH2).

[0106] Both Ph-NHOH and Ph-NH2 can perform conjugated addition to acrylic acid double bonds. Ph-NHOH, due to its higher nucleophilicity, exhibits a significantly faster addition rate to α,β-unsaturated carbonyl groups than Ph-NH2. It can efficiently nucleophilically attack acrylic or methacrylic acid double bonds on the surface of nanoparticles in a room-temperature aqueous environment, generating stable β-amino esters. Although Ph-NH2 has weaker nucleophilicity, its aza-Michael addition can still occur effectively in the high-density acrylic acid double bond environment on the nanoparticle surface. For difunctionalized azide systems, each molecule can simultaneously generate two addable nitrogen sources after photolysis, thus enabling covalent bonding of double bonds on the surfaces of two different nanoparticles.

[0107] Furthermore, Ph-NH2 and Ph-NHOH are not species whose reactions terminate in a single step; their aza-Michael addition to the acrylic acid double bond exhibits a chain-like characteristic: a single nitrogen atom can continuously add to multiple surface double bonds, or participate in subsequent free radical reactions via chain transfer, thus resulting in a significant reaction amplification effect. This means that even Ph 1 Nitrogen (N) itself is captured by aqueous activators (such as water) and no longer participates in addition reactions. The resulting amine compounds can still undergo multi-step addition and bridging on the surface of nanoparticles with high double bond density, ensuring that photocrosslinking efficiency not only does not decrease in a high water ratio environment but is significantly improved. Overall, "Ph 1 N → PhNH + The sequence "→ Ph-NHOH / Ph-NH2→ Michael addition" constitutes an alternative chemical pathway that dominates the crosslinking of metal oxide nanoparticles in systems with aqueous activators (e.g., water).

[0108] In summary, the increase in reactivity after the addition of aqueous activators (such as water) is mainly due to the following two reasons: (1) Ph 1The N protonation reaction inhibits the occurrence of other side reactions, generating stable and long-lived aromatic hydroxylamines and aromatic amines, avoiding the deactivation of nitrobenes due to side reactions, and providing sufficient active species for subsequent crosslinking; (2) In the high-density acrylic double bond environment on the surface of nanoparticles, amine products achieve multi-site bridging and network crosslinking through sustainable aza-Michael nucleophilic addition. This process not only compensates for the initial loss of nitrobenes, but also significantly improves the final crosslinking efficiency in the environment of aqueous activators (such as water) due to its multi-site and chain reaction characteristics.

Claims

1. A method for preparing a photoresist composition, characterized in that, Including the following steps: Metal oxide nanoparticles, azide photoinitiator, and solvent are mixed to obtain an intermediate mixture; An aqueous activator is added to the intermediate mixture, and the mixture is then mixed to obtain the photoresist composition. The aqueous activator is an aqueous solvent with a polarity greater than or equal to that of water. Based on the total mass of the photoresist composition, the percentage of the aqueous activator added is 0.5~7.5wt%.

2. The method according to claim 1, characterized in that, When the percentage of aqueous activator added is 0.5~1.5wt%, adding aqueous activator to the intermediate mixture includes adding the aqueous activator itself directly to the intermediate mixture.

3. The method according to claim 1, characterized in that, When the percentage of aqueous activator added is greater than 1.5 wt% and less than 7.5 wt%, adding aqueous activator to the intermediate mixture includes pre-mixing the aqueous activator with at least a portion of the solvent to obtain an activated solvent, and then adding the activated solvent to the intermediate mixture.

4. The method according to claim 1, characterized in that, The aqueous activator is water.

5. The method according to any one of claims 1 to 4, characterized in that, The mass ratio of the azide photoinitiator to the aqueous activator is (0.1~100):

1.

6. The method according to claim 5, characterized in that, The mass ratio of the azide photoinitiator to the aqueous activator is (0.5~25):

1.

7. The method according to any one of claims 1 to 4, characterized in that, The metal oxide nanoparticles have the general formula Zr x Q y L n In this context, x and y are independent integers from 1 to 10, Q is one or both of O and OH, L is an organic ligand containing a double bond, and x:n = 1:(0.1~10).

8. The method according to any one of claims 1 to 4, characterized in that, Based on the total mass of the photoresist composition, the mass percentage of the metal oxide nanoparticles is 1 to 50 wt%, and the mass percentage of the azide photoinitiator is greater than 0 and less than or equal to 2.5 wt%.

9. The method according to any one of claims 1 to 4, characterized in that, The azido photoinitiator is selected from 2,6-bis-(4-azidobenzyl)cyclohexanone, 2,6-di(4-azidobenzyl)-4-methylcyclohexanone, (1E,4E)-1,5-bis(4-azido-2,3,5,6-tetrafluorophenyl)pentyl-1,4-dien-3-one, ethane-1,2-diylbis(4-azido-2,3,5,6-tetrafluorobenzoate), and 4,4'-biphenyl dibenzyl azido. The solvent is selected from propylene glycol monomethyl ether acetate, toluene, dimethyl carbonate, N,N-dimethylformamide, and acetylacetone; and / or The organic ligands of the metal oxide nanoparticles are selected from acrylic acid, methacrylic acid and 3,3-dimethacrylic acid.

10. The method according to claim 9, characterized in that, The metal oxide nanoparticles are crystals with a particle size between 1 and 5 nm.

11. The method according to claim 7, characterized in that, The metal oxide nanoparticles are Zr6O4(OH)4(C4H5O2). 12 .

12. A photoresist composition, characterized in that, Prepared by the method according to any one of claims 1 to 11.

13. A method for forming a photolithographic pattern, characterized in that, Including the following steps: The photoresist composition according to claim 12 is coated on a substrate to form a photoresist coating; The substrate having the photoresist coating is exposed under energy irradiation; The exposed substrate is developed using a developer.

14. The method according to claim 13, characterized in that, The energy irradiation is ultraviolet light with a wavelength of 245 nm or 365 nm, and the exposure dose is 14~45 mJ / cm. 2 .

15. The method according to claim 13, characterized in that, The developer is selected from benzene, o-xylene, m-xylene, p-xylene, ethyl acetate, butyl acetate, ethanol, n-propanol, isopropanol, n-butanol, n-hexane, cyclohexane, and decahydronaphthalene.

16. The method according to any one of claims 13 to 15, characterized in that, It also includes a step of pre-baking the substrate after the coating step, preferably pre-baking at 60~120°C for 0.5~1.5 min.

17. The method according to any one of claims 13 to 15, characterized in that, It also includes a post-baking step of the substrate after the exposure step, preferably post-baking at 90~120°C for 1~4 min.

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