A nanoimprint photoresist with high mechanical strength and high resolution and an inkjet printing method thereof

Abstract

The present invention discloses a nanoimprint photoresist with high mechanical strength and high resolution and an inkjet printing method thereof. The nanoimprint photoresist of the present invention is mainly designed for the compatibility of inkjet printing and nanoimprint technology and high-precision manufacturing in the semiconductor field. After screening and blending, the inkjet print head can distribute photoresist droplets as needed, quickly print the required pattern, and finally achieve 50 nm high-resolution imprinting through nanoimprint lithography exposure. Compared with the nanoimprint photoresist in the prior art, the nanoimprint photoresist of the present invention has the advantages of fast inkjet printing, fast curing rate, excellent anti-oxidation and polymerization inhibition performance, high mechanical strength, high resolution and easy demoulding. The present invention aims to improve the operability and reliability of nanoimprint photoresist in practical applications, and has potential application prospects in high-precision manufacturing fields such as advanced semiconductor processes.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanoimprinting, and particularly relates to a nanoimprint lithography resist with high mechanical strength and high resolution and an inkjet printing method thereof. Background Art

[0002] Nanoimprint lithography (NIL) is an advanced micro-nano manufacturing process that can repeatedly replicate the structures on a mold onto the surface of a target substrate in proportion. After more than two decades of development, NIL technology has been proven to be able to efficiently and low-costly replicate nano-features smaller than 10 nm, and thus has gradually become a powerful alternative to traditional high-end lithography technologies such as ion beam etching, electron beam lithography, and extreme ultraviolet lithography.

[0003] According to different material and process requirements, nanoimprint lithography technology is mainly divided into thermal nanoimprint and ultraviolet nanoimprint (UV-NIL). Compared with thermal nanoimprint, due to the characteristics of UV-NIL technology that it does not require high temperature and high pressure and can be quickly completed at room temperature and low pressure, it is highly favored in the industry. In UV-NIL technology, inkjet UV-NIL is regarded as one of the most commercially promising technologies. Through inkjet printing technology, the prepolymer liquid of the nanoimprint lithography resist can be quickly and precisely distributed onto the surface of the wafer according to the designed circuit pattern. However, the compatibility between inkjet printing technology and nanoimprint lithography technology is facing some challenges, such as problems like the viscosity of the lithography resist, curing speed, and precise control during the inkjet process, which need to be solved by continuously optimizing material and process parameters. The integration of inkjet printing technology and nanoimprint lithography technology not only requires precise adjustment technically but also needs to develop high-performance lithography resist materials for specific applications to ensure the maximum synergistic effect of the two. For example, in the field of advanced semiconductor manufacturing processes, in order to ensure the high resolution and stability of the final imprinted pattern, the nanoimprint lithography resist must have characteristics such as low viscosity, fast curing, no residue, antioxidant and anti-polymerization, good mechanical strength, and high resolution.

[0004] Therefore, developing a nanoimprint lithography resist suitable for inkjet printing, with high mechanical strength and high resolution, not only has important theoretical significance but also has potential application value in promoting the practical application and industrialization of nanoimprint lithography technology. Summary of the Invention

[0005] Aiming at the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a nanoimprint lithography resist with high mechanical strength and high resolution and an inkjet printing method thereof. The nanoimprint lithography resist prepared by the present invention has the characteristics of being capable of rapid inkjet printing, fast curing rate, antioxidant and anti-polymerization, high mechanical strength, high resolution, and easy demolding.

[0006] The nanoimprint lithography resist with high mechanical strength and high resolution of the present invention has the following raw materials by mass percentage:

[0007] Rigid monomer containing double bond: 50 wt% - 95 wt%, rigid compound containing mercapto group: 0 wt% - 20 wt%, photoinitiator: 1 wt% - 20 wt%, organic solvent: 0 wt% - 20 wt%.

[0008] Further preferably: rigid monomer containing double bond: 80 wt% - 95 wt%, rigid compound containing mercapto group: 1 wt% - 10 wt%, photoinitiator: 1 wt% - 10 wt%, organic solvent: 0 wt% - 15 wt%.

[0009] Even more preferably: rigid monomer containing double bond: 85 wt% - 95 wt%, rigid compound containing mercapto group: 1 wt% - 5 wt%, photoinitiator: 1 wt% - 5 wt%, organic solvent: 0 wt% - 1 wt%.

[0010] The rigid monomer containing double bond is selected from one or a mixture of the following substances: styrene, divinylbenzene, 4 - vinylpyridine, N - vinylpyrrolidone, 2,4,6 - triallyloxy - 1,3,5 - triazine, 1,4 - cyclohexanedimethanol divinyl ether, benzyl methacrylate, phenyl methacrylate, benzyl acrylate, phenyl acrylate, isobornyl acrylate, glycidyl methacrylate, glycidyl acrylate, 2 - naphthyl acrylate, trimethylsilyl acrylate, 2 - phenoxyethyl acrylate, glucose acrylate, allyl phenyl ether, acetone glycerol acrylate, acetone glycerol methacrylate, styryl acrylate, phenethyl methacrylate, trifluoromethylphenyl acrylate, dicyclopentadiene acrylate, 1 - acryloyloxyadamantane, o - phenylphenoxyethyl acrylate, diallyl isophthalate, triallyl 1,3,5 - benzenetricarboxylate, diethylene glycol diacrylate terephthalate, diethylene glycol dimethacrylate phthalate, diethylene glycol dimethacrylate isophthalate, dipropylene glycol diacrylate terephthalate, dipropylene glycol dimethacrylate phthalate, dipropylene glycol dimethacrylate isophthalate, dibutylene glycol diacrylate terephthalate, dibutylene glycol dimethacrylate phthalate, dibutylene glycol dimethacrylate isophthalate, cyclohexanedimethanol ester, cyclohexanedimethanol dimethacrylate, bisphenol A glycerol ester, N - hydroxysuccinimide acrylate, pyrrole acrylate, thiophene acrylate. Further preferably, it is one or several of cyclohexanedimethanol dimethacrylate, bisphenol A glycerol ester, diethylene glycol diacrylate isophthalate, acetone glycerol methacrylate.

[0011] The rigid compound containing a mercapto group is selected from one or a mixture of the following substances: 2,6-naphthalenedithiol, 4,4'-dimercapto diphenyl ether, 4,4'-thiobisbenzenethiol, dimercaptothiadiazole, tetramercaptobenzene, biphenyl-4,4'-dithiol, 1,3,5-benzenetrithiol, trimercaptotriazine, 2,7-naphthalenedithiol, 1,5-dimercaptonaphthalene, 2,2'-dimercaptobiphenyl, 2,5-dimercaptobenzene, 4,4'-dimercapto stilbene, 2,2'-dimercaptopyridine, 2,5-dimercaptopyrazole, dimercaptoacetophenone, 2,6-dimercaptothiophene, 3,5-dimercapto-1,2,4-triazole, dimercaptosilane, 2,6-dimercaptopyridine. Further preferably, it is one or several of tetramercaptobenzene and 1,3,5-benzenetrithiol.

[0012] The photoinitiator is selected from one or a mixture of the following substances: benzoin dimethyl ether, 2-hydroxy-2-methyl-1-phenylpropanone, benzoin ethyl ether, benzil, benzophenone, methyl o-benzoylformate, 2-hydroxy-4-(2-hydroxyethoxy)-2-methylpropiophenone, 2-isopropyl-thioxanthen-9-one, 4-phenybenzophenone, methyl α-oxophenylacetate, 2-hydroxy-2-methylphenylpropan-1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2,2-dimethoxy-2-phenylacetophenone. Further preferably, it is one or several of 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one and 2-hydroxy-2-methylphenylpropan-1-one.

[0013] The organic solvent is selected from one or a mixture of the following substances: acetone, propylene glycol methyl ether acetate, acetonitrile, tetrahydrofuran, toluene, dimethylformamide, dimethyl sulfoxide. Further preferably, they are acetone and propylene glycol methyl ether acetate.

[0014] The organic solvent is a selective component. When the components of the nanoimprint lithography resist meet the requirements of inkjet printing and imprinting, or the addition of the organic solvent will affect the final imprinting effect, the organic solvent may not be added.

[0015] The inkjet printing method of the nanoimprint lithography resist of the present invention includes the following steps:

[0016] Step 1: Mix the rigid monomer containing a double bond, the rigid compound containing a mercapto group, the photoinitiator and the organic solvent, stir and mix evenly under light-shielded conditions, and filter to obtain the nanoimprint lithography resist.

[0017] Step 2: Perform a tackifying treatment on the silicon wafer. The specific steps are as follows:

[0018] Drop 0.2 - 1 mL of the tackifier onto the silicon wafer adsorbed by vacuum in a spin coater. After spin coating, transfer the silicon wafer coated with the tackifier to a hot stage for baking. After baking, take it out and let it cool to room temperature for standby. The silicon wafer after the tackifying treatment in this step is hereinafter collectively referred to as the substrate.

[0019] Step 3: Inject 1 - 2 mL of the nanoimprint lithography resist obtained in Step 1 into the ink sac of the inkjet printer cartridge, then connect the cartridge to the inkjet printer interface. Set the required inkjet pattern as a droplet array through the program, align the print head with the substrate through the display screen. After the inkjet printer runs for 5 - 300 s, the corresponding inkjet pattern can be obtained on the substrate.

[0020] Step 4: Transfer the substrate with the inkjet pattern obtained in Step 3 to the vacuum chuck of the nanoimprint lithography machine, turn on the air pump to fix the substrate, and align the substrate directly below the quartz mold. Adjust the imprint voltage of the nanoimprint lithography machine to 1 - 10 volts, so that the mold moves down to contact the droplet array on the substrate. After the nanoimprint lithography resist fully fills the mold gap, turn on the ultraviolet light for curing. After curing is completed, turn off the ultraviolet lamp and separate the mold.

[0021] In Step 1, the pore size of the filter used during filtration is 0.2 - 2 μm.

[0022] In Step 1, the viscosity of the obtained nanoimprint lithography resist is 1 - 20 centipoise, preferably 7 - 10 centipoise.

[0023] In Step 2, the tackifier is a mixture of 3 - trimethoxysilylpropyl acrylate, propylene glycol methyl ether acetate, and acetone, and the mass ratio of the three mixtures is 0.5 - 2 g: 0.5 - 1.5 g: 0.1 - 0.5 g.

[0024] In Step 2, set the rotation speed of the spin coater to 1000 - 3000 revolutions and the spin coating time to 30 - 90 s.

[0025] In Step 2, the baking temperature is 50 - 150 °C and the baking time is 1 - 2 min.

[0026] In Step 3, the area of inkjet printing is preferably 1 - 50 mm 2 , more preferably 1 - 25 mm 2; The inkjet voltage is preferably 10 - 40 volts, more preferably 20 - 30 volts; the inkjet air pressure is preferably 0 - 40 psi, more preferably 1 - 10 psi; the inkjet frequency is preferably 500 - 7000 Hz, more preferably 3000 - 5000 Hz; the inkjet droplet diameter is preferably 10 - 50 μm, more preferably 20 - 40 μm; the inkjet droplet point spacing is preferably 10 - 100 μm, more preferably 70 - 100 μm; the nozzle temperature is preferably 20 - 60 °C, more preferably 20 - 30 °C; the substrate temperature is preferably 20 - 90 °C, more preferably 20 - 30 °C.

[0027] In step 4, the ultraviolet light power is 50 - 110 mW and the curing time is 10 - 30 s.

[0028] The preparation of the test specimen and the mechanical property characterization of the nanoimprint lithography resist of the present invention include the following steps:

[0029] (1) Take 0.5 - 1 mL of the above-prepared nanoimprint lithography resist, pass it through a filter with a pore size of 0.2 μm, and inject it into a square hollow area with a side length of 40 - 80 mm and a thickness of 0.1 - 0.4 mm.

[0030] (2) Move the entire square hollow area containing the nanoimprint lithography resist to directly below the light source of the nanoimprint lithography machine, adjust the program voltage to 1 - 10 volts so that the blank quartz on the nanoimprint lithography machine is completely in contact with the nanoimprint lithography resist in the square hollow and air bubbles are excluded, turn on the ultraviolet light irradiation for curing, the power of the ultraviolet light is 50 - 110 mW, the irradiation time is 60 - 300 s, after curing is completed, turn off the ultraviolet lamp and separate from the quartz, and then carefully peel off the cured nanoimprint lithography resist.

[0031] (3) Use a type 4 cutter with a size of 2 mm × 35 mm that complies with the GB / T 528 - 2009 standard to cut the cured nanoimprint lithography resist in the above step, and finally obtain a standard dumbbell-shaped specimen.

[0032] (4) Use the above standard dumbbell-shaped specimen to conduct stress-strain tests on a universal tensile machine, and the tensile rate is 5 mm / min.

[0033] The Young's modulus of the nanoimprint lithography resist of the present invention is 0.001 - 1.5 GPa, more preferably 0.8 - 1.2 GPa; the fracture strength of the nanoimprint lithography resist is 0.5 - 35 MPa, more preferably 10 - 35 MPa; the fracture strain of the nanoimprint lithography resist is 1 - 50%, more preferably 5 - 15%.

[0034] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0035] (1) At room temperature, it has a low viscosity (liquid phase, 7 - 10 centipoises), can be rapidly dispensed through an inkjet print head, and then rapidly cured by nanoimprint lithography (10 s). To a certain extent, it effectively solves the compatibility problem between inkjet printing technology and nanoimprint lithography technology.

[0036] (2) After curing, it basically does not adhere to the mold, can be released from the mask well and preferably adheres to the substrate, which can avoid pattern defects and repeated defects in subsequent imprinting.

[0037] (3) It resists oxygen inhibition and polymerization, ensures complete curing of the nanoimprint photoresist, reduces microstructural defects, and improves pattern accuracy.

[0038] (4) It has high mechanical strength, ensuring high replication accuracy of patterns and high resolution (≤50 nm) of imprinted patterns during the curing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Shows the inkjet printing pattern of a representative nanoimprint photoresist PR - 2.

[0040] Figure 2 Shows the device for preparing nanoimprint photoresist (a) and the pattern of a standard dumbbell - shaped specimen (b).

[0041] Figure 3 Shows the stress - strain curve pattern of nanoimprint photoresist PR - 1.

[0042] Figure 4 Shows the stress - strain curve pattern of nanoimprint photoresist PR - 2.

[0043] Figure 5 Shows the stress - strain curve pattern of nanoimprint photoresist PR - 3.

[0044] Figure 6 Shows the imprinted pattern of nanoimprint photoresist PR - 1.

[0045] Figure 7 Shows the imprinted pattern of nanoimprint photoresist PR - 2. DETAILED DESCRIPTION OF THE INVENTION

[0046] The present invention will be further described in detail below with reference to the embodiments and the drawings, but the embodiments of the present invention are not limited thereto. The implementation conditions adopted in the embodiments can be further adjusted according to the situation, and the implementation conditions not specified are usually those in conventional experiments.

[0047] Examples 1 - 7 are about the formulation and preparation of a nanoimprint photoresist with high mechanical strength and high resolution.

[0048] Example 1:

[0049] In this example, a nanoimprint lithography resist with high mechanical strength and high resolution (nanoimprint lithography resist PR-1) is obtained by uniformly mixing each component according to Formulation 1. The formulation is shown in Table 1 below.

[0050]

[0051] Example 2:

[0052] In this example, a nanoimprint lithography resist with high mechanical strength and high resolution (nanoimprint lithography resist PR-2) is obtained by uniformly mixing each component according to Formulation 2. The formulation is shown in Table 2 below.

[0053]

[0054] Example 3:

[0055] In this example, a nanoimprint lithography resist with high mechanical strength and high resolution (nanoimprint lithography resist PR-3) is obtained by uniformly mixing each component according to Formulation 3. The formulation is shown in Table 3 below.

[0056]

[0057] Example 4:

[0058] The difference between Example 4 and Example 2 is that 1,4-cyclohexanedimethanol divinyl ether is used to replace cyclohexanedimethanol dimethacrylate, and benzyl methacrylate is used to replace acetone glycerol dimethacrylate in the components. The replaced formulation is called nanoimprint lithography resist PR-4.

[0059] Example 5:

[0060] The difference between Example 5 and Example 2 is that divinylbenzene is used to replace cyclohexanedimethanol dimethacrylate and diethylene glycol diacrylate of isophthalic acid in the components. The replaced formulation is called nanoimprint lithography resist PR-5.

[0061] Example 6:

[0062] The difference between Example 6 and Example 2 is that diallyl isophthalate is used to replace cyclohexanedimethanol dimethacrylate and diethylene glycol diacrylate of isophthalic acid in the components. The replaced formulation is called nanoimprint lithography resist PR-6.

[0063] Example 7:

[0064] The difference between this Example 7 and Example 2 is that 2,4,6-triallyloxy-1,3,5-triazine is used in the components to replace cyclohexanedimethanol dimethacrylate and diethylene glycol diacrylate of isophthalic acid. The formula after replacement is called nanoimprint lithography resist PR-7.

[0065] Example 8:

[0066] After preparing the nanoimprint lithography resist according to each formula in Examples 1 to 7, its viscosity was tested using a rotational viscometer. The volume of the nanoimprint lithography resist for each formula was 6 - 7 mL, and the parameter settings of the viscometer were: the rotor type was 18#, the rotation speed was 90 revolutions, the test temperature was 25°C, the test time was 30 s, and the viscosity value was recorded after the test.

[0067]

[0068] Example 9:

[0069] After preparing the nanoimprint lithography resist according to each formula in Examples 1 to 7, it was used as follows:

[0070] (1) Clean the substrate. Ultrasonic the silicon wafer in acetone, isopropanol, and water for 10 min in sequence, and then treat it with oxygen plasma for 2 min.

[0071] (2) Perform a tackifying treatment on the above silicon wafer. First, prepare a tackifier. A mixture of 3-trimethoxysilylpropyl acrylate, propylene glycol methyl ether acetate, and acetone was prepared as a tackifier according to a mass ratio of 1 g:0.75 g:0.1 g. Drop 0.5 mL of the tackifier onto the silicon wafer in step (1) that has been adsorbed and fixed in the spin coater. Set the parameters of the spin coater, with a rotation speed of 2000 revolutions and a spin coating time of 45 s. After waiting for the spin coating to finish, remove the silicon wafer coated with the tackifier and transfer it to a hot plate for baking. The baking temperature is 120°C, and the baking time is 2 min. After waiting for the baking to finish, take out the treated silicon wafer and let it cool to room temperature for use (the silicon wafer after the tackifying treatment is hereinafter referred to as the substrate).

[0072] (3) Inject 1.5 mL of the prepared nanoimprint lithography resist into the ink cartridge of the inkjet printer after filtering. The pore size of the filter is 0.2 μm. Then connect the ink cartridge containing the nanoimprint lithography resist to the inkjet printer interface. Set the inkjet pattern in the program to a droplet array, and set the inkjet printing area to 2 mm 2 , the inkjet voltage is 25 volts, the inkjet air pressure is 1 pound-force per square inch, the inkjet frequency is 5000 hertz, the inkjet dot pitch is 80 μm, the nozzle temperature is 25°C, the substrate temperature is 25°C, and align the nozzle with the center of the substrate through the operation display screen. After the inkjet printer runs for 30 s, an area of 2 mm can be obtained on the substrate 2The inkjet pattern is then observed under a microscope.

[0073] (4) Transfer the substrate with the inkjet pattern to the vacuum chuck of the nanoimprint lithography machine and fix it. Adjust the imprinting voltage of the nanoimprint lithography machine to 6 V for alignment, so that the quartz mold directly above the substrate moves down to contact the droplet array on the substrate. After waiting for the nanoimprint photoresist to fully fill the mold gap, turn on the ultraviolet light for irradiation and curing. The power of the ultraviolet light is 110 mW, and the irradiation time is 10 s or 30 s. After the curing is completed, turn off the ultraviolet lamp and click the "demolding" button to separate the mold.

[0074] (5) Observe the effect of inkjet curing under a microscope, including: the liquid film residue of the nanoimprint photoresist after ultraviolet light irradiation and the residue of the cured nanoimprint photoresist on the mold.

[0075]

[0076] (6) The inkjet pattern prepared as a representative Example 2 is as Figure 1 shown, and the imprinted patterns of the nanoimprint photoresist of representative Example 1 and Example 2 are respectively as Figure 6 and Figure 7 shown.

[0077] The purpose of this example is to illustrate that

[0078] ① By observing the inkjet pattern under a microscope ( Figure 1 ), the viscosity of the nanoimprint photoresist is 7-10 centipoise, the inkjet voltage is 25 V, the inkjet air pressure is 1 psi, the inkjet frequency is 5000 Hz, the inkjet droplet diameter is 40 μm, the inkjet droplet pitch is 80 μm, the nozzle temperature is 25 °C, and the substrate temperature is 25 °C. At this time, a relatively uniform droplet array can be inkjet printed.

[0079] ② The nanoimprint photoresist can be completely cured within a very short exposure time (without liquid film residue), which is attributed to the rapidity of the free radical polymerization reaction during the polymerization process and the antioxidant and polymerization inhibition effect provided by the thiol.

[0080] ③ The acrylate double bond components contained in the thickener may participate in the photocuring process of the nanoimprint photoresist. Therefore, during the demolding process, the nanoimprint photoresist will selectively remain on one side of the substrate and hardly leave residues on the mold, thus ensuring the cleanliness of the mold.

[0081] Example 10:

[0082] After preparing the nanoimprint photoresist according to each formula in Examples 1-3, prepare the standard dumbbell-shaped specimens of the nanoimprint photoresist for mechanical property testing according to the following steps:

[0083] (1) Take 0.6 mL of the nanoimprint photoresist prepared according to each recipe of Examples 1 to 3, pass it through a filter with a pore size of 0.2 μm, and inject it into the following: Figure 2 In the square hollow area with a side length of 40 mm and a thickness of 200 μm shown in a, Figure 2 The silicon wafer in a has been subjected to adhesion enhancement treatment according to step (2) in Example 9.

[0084] (2) Move the square hollow device containing nanoimprint photoresist into the bottom of the light source of the nanoimprint lithography machine, adjust the program voltage of the nanoimprint lithography machine to 6 volts, so that the blank quartz on the nanoimprint lithography machine moves down and fits closely with the nanoimprint photoresist liquid in the square hollow and fully removes bubbles, turn on ultraviolet light for curing, the power of ultraviolet light is 110 mW, the irradiation time is 300 s, after the curing is completed, turn off the ultraviolet light, click the "mold release" button to detach from the quartz, and then carefully peel off the nanoimprint photoresist.

[0085] (3) Using a 2 mm × 35 mm type 4 cutter that complies with the GB / T 528-2009 standard, the nanoimprint photoresist prepared in the above step is cut to obtain the following: Figure 2 b shows the standard dumbbell spline.

[0086] (4) The stress-strain test was carried out on a universal tensile machine using the above standard dumbbell-shaped specimens at a tensile rate of 5 mm / min. The stress-strain test of each formulation was conducted at least three times.

[0087] The stress-strain test results of the standard dumbbell-shaped specimens prepared in Examples 1 to 3 are as follows Figures 3 to 5 As shown in the figure, since the photocuring effect of the nanoimprint photoresists in Examples 4 to 7 is poor, no further research on the mechanical properties was conducted.

[0088]

[0089] Example 11:

[0090] The purpose of this example is to illustrate the effect of organic solvents in nanoimprint photoresist formulations on the mechanical properties of nanoimprint photoresist.

[0091] As shown in Table 6, Figure 3 ​​​​​​​As shown, when an organic solvent is added as a viscosity regulator to the formulation of the nanoimprint photoresist, the addition of a small amount of the solvent results in only extremely low mechanical strength of the nanoimprint photoresist PR-1. This may be because the small solvent molecules interfere with and destroy the original cross-linking points, and at the same time weaken the intermolecular forces between the chains after penetrating between the polymer chains, thereby reducing the compactness of the cross-linked network. With the relaxation of the cross-linked structure, the rigidity of the material decreases significantly, leading to a sharp deterioration of the mechanical properties.

[0092] Example 12:

[0093] The purpose of this example is to illustrate the influence of the change in the amount of photoinitiator in the nanoimprint photoresist formulation on the mechanical properties of the nanoimprint photoresist.

[0094] Analyze Table 6, Figure 4 and Figure 5 , when the amount of photoinitiator in the nanoimprint photoresist PR-3 is increased to twice the amount of photoinitiator in PR-2, at the same exposure time, the Young's modulus and fracture strength of PR-3 are reduced to about half of those of PR-2. This may be because the excessive amount of photoinitiator leads to too fast a cross-linking reaction rate, resulting in an uneven cross-linking process and forming an irregular cross-linked network structure. This uneven cross-linked network affects the mechanical properties of the material, thereby leading to a significant decrease in its Young's modulus and fracture strength.

[0095] Example 13:

[0096] The purpose of this example is to illustrate the importance of the high mechanical strength of the nanoimprint photoresist for imprinting high-resolution nanostructures.

[0097] Analyze Table 6, Figure 3 and Figure 4 , comparing the nanoimprint photoresist PR-1 with the nanoimprint photoresist PR-2, the fracture strain of PR-1 (8.9 ± 0.300 %) is higher than that of PR-2 (6.9 ± 0.0109 %), and the Young's modulus and fracture strength of PR-1 are much lower than those of PR-2. In contrast, there are many obvious defects in the imprinted "grating" of the nanoimprint photoresist PR-1 ( Figure 6 ). This shows that when the fracture strains are similar, the higher Young's modulus (> 1.1 GPa) and fracture strength (> 30 MPa) in the nanoimprint photoresist PR-2 may be the key to ensuring imprinting of high resolution less than 50 nm ( Figure 7 ).

[0098] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be equivalent substitution methods and are all included in the protection scope of the present invention.

Claims

1. A nanoimprint photoresist, characterized in that The raw materials are composed of the following by mass percentage: 85 wt%~95 wt% of rigid monomer containing double bonds, 1 wt%~5 wt% of rigid compound containing thiol groups, 1 wt%~5 wt% of photoinitiator, 0 wt%~1 wt% of organic solvent; The double-bond-containing rigid monomer is selected from one or more of cyclohexanedimethanol dimethacrylate, bisphenol A glycerol ester, isophthalic acid diethylene glycol diacrylate, and methacrylate acetone glycerol ester; The mercapto-containing rigid compound is selected from one or more of tetramercaptobenzene and 1,3,5-benzenetrithiol.

2. The nanoimprint photoresist according to claim 1, characterized in that: The photoinitiator is selected from one of the following substances or a mixture thereof: benzoin dimethyl ether, 2-hydroxy-2-methyl-1-phenylpropanone, benzoin ethyl ether, dibenzoyl, benzophenone, methyl o-benzoyl, 2-hydroxy-4-(2-hydroxyethoxy)-2-methylpropiophenone, 2-isopropyl-thioxanthen-9-one, 4-phenylbenzophenone, A-oxyphenylacetic acid methyl ester, 2-hydroxy-2-methylphenylpropane-1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholine-1-propanone, and 2,2-dimethoxyphenylacetophenone.

3. The inkjet printing method of the nanoimprint photoresist according to any one of claims 1 to 2, characterized in that The steps include: Step 1: Mix a rigid monomer containing a double bond, a rigid compound containing a thiol group, a photoinitiator and an organic solvent, stir and mix them evenly under light-proof conditions, and obtain a nanoimprint photoresist after filtering; The viscosity of the obtained nanoimprint photoresist is 1 to 20 centipoise; Step 2: Perform adhesion enhancement treatment on the silicon wafer; Step 3: Inject 1-2 mL of the nanoimprint photoresist obtained in step 1 into the ink sac of the inkjet printer cartridge, then connect the inkjet printer cartridge to the interface of the inkjet printer, set the required inkjet pattern to a droplet array through the program, align the print head with the substrate through the display screen, and after the inkjet printer runs for 5-300 s, the corresponding inkjet pattern can be obtained on the substrate; Step 4: Transfer the substrate with the inkjet pattern obtained in step 3 to the vacuum chuck of the nanoimprint lithography machine, turn on the air pump to fix the substrate, and align the substrate with the bottom of the quartz mold, adjust the imprint voltage of the nanoimprint lithography machine at 1-10 volts, so that the mold moves down and contacts the droplet array on the substrate, and after the nanoimprint photoresist fully fills the gap in the mold, turn on ultraviolet light for curing, and after the curing is completed, turn off the ultraviolet lamp and remove from the mold; In step 3, the area of ​​inkjet printing is 1~50 mm 2 , the inkjet voltage is 10~40 volts, the inkjet air pressure is 0~40 lbf / square inch, the inkjet frequency is 500~7000 Hz, the inkjet droplet diameter is 10~50 μm, the inkjet droplet point spacing is 10~100 μm, the nozzle temperature is 20~60°C, and the substrate temperature is 20~90°C.

4. The inkjet printing method according to claim 3, characterized in that: In step 2, the viscosity increasing treatment comprises the following steps: Drop 0.2-1 mL of the thickener on the vacuum-adsorbed silicon wafer in the spin coater. After the spin coating is completed, transfer the silicon wafer coated with the thickener to a hot plate for baking. After the baking is completed, take it out and cool it to room temperature for later use. The tackifier is a mixture of 3-trimethoxysilane propyl acrylate, propylene glycol methyl ether acetate and acetone.

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