Nanoimprint lithography resist having high mechanical strength and enabling high resolution and inkjet printing method therefor

Abstract

A nanoimprint lithography resist having high mechanical strength and enabling high resolution and an inkjet printing method therefor. The raw materials of the nanoimprint lithography resist comprise, in mass percentage: 50 wt%-95 wt% of a rigid monomer containing double bonds, 0 wt%-20 wt% of a rigid compound containing thiol groups, 1 wt%-20 wt% of a photoinitiator, and 0 wt%-20 wt% of an organic solvent. The nanoimprint lithography resist is designed for compatibility between inkjet printing and nanoimprint lithography and for high-precision manufacturing in the field of semiconductors, and is capable of being dispensed as resist droplets on demand by an inkjet printhead to rapidly print a desired pattern, and finally achieving high-resolution imprinting of 50 nm by means of exposure by a nanoimprint lithography machine. The nanoimprint lithography resist has advantages such as rapid inkjet printability, a fast curing rate, excellent oxygen inhibition resistance, high mechanical strength, high resolution, and easy demolding, thereby improving the operability and reliability of the nanoimprint lithography resist in practical applications and having potential application prospects in high-precision manufacturing fields such as advanced semiconductor processes.

Description

A high-strength and high-resolution nanoimprint photoresist and its inkjet printing method Technical Field

[0001] This invention belongs to the technical field of nanoimprinting, specifically relating to a high-mechanical-strength and high-resolution nanoimprinting photoresist and its inkjet printing method. Background Technology

[0002] Nanoimprint lithography (NIL) is an advanced micro- and nano-manufacturing process that can repeatedly replicate structures on a mold to the surface of a target substrate in a proportional manner. After more than 20 years of development, NIL technology has been proven to be able to efficiently and cost-effectively replicate nanoscale features smaller than 10 nm, and has therefore gradually become a powerful alternative to traditional high-end lithography technologies such as ion beam etching, electron beam lithography, and extreme ultraviolet lithography.

[0003] Depending on the different material and process requirements, nanoimprint technology is mainly divided into thermal nanoimprinting and ultraviolet nanoimprinting (UV-NIL). Compared with thermal nanoimprinting, UV-NIL technology is favored in the industry because it does not require high temperature and high pressure and can be completed rapidly at room temperature and low pressure. Among UV-NIL technologies, inkjet UV-NIL is considered one of the most commercially promising technologies. Through inkjet printing technology, the prepolymer liquid of nanoimprint photoresist can be rapidly and accurately distributed onto the wafer surface according to the designed circuit pattern. However, the compatibility between inkjet printing technology and nanoimprinting technology is facing some challenges, such as the viscosity of the photoresist, the curing speed, and the precise control of the inkjet process. These issues need to be addressed through continuous optimization of material and process parameters. The integration of inkjet printing technology and nanoimprinting technology not only requires precise technical formulation but also the development of high-performance photoresist materials for specific applications to ensure the maximum synergistic effect of both. For example, in the field of advanced semiconductor manufacturing, in order to ensure the high resolution and stability of the final imprinted pattern, nanoimprint photoresist must have characteristics such as low viscosity, fast curing, no residue, anti-oxidation and polymerization inhibition, good mechanical strength and high resolution.

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

[0005] To address the problems existing in the prior art, the present invention aims to provide a nanoimprint photoresist with high mechanical strength and high resolution, and its inkjet printing method. The nanoimprint photoresist prepared by the present invention has the characteristics of rapid inkjet printing, fast curing rate, oxidation resistance and polymerization inhibition, high mechanical strength, high resolution, and easy demolding.

[0006] The high mechanical strength and high resolution nanoimprint photoresist of this invention is composed of the following raw materials by mass percentage:

[0007] Rigid monomers containing double bonds: 50 wt%–95 wt%; rigid compounds containing thiol groups: 0 wt%–20 wt%; photoinitiators: 1 wt%–20 wt%; organic solvents: 0 wt%–20 wt%.

[0008] Further preferred formulation: 80wt%–95wt% of rigid monomers containing double bonds, 1wt%–10wt% of rigid compounds containing thiol groups, 1wt%–10wt% of photoinitiator, and 0wt%–15wt% of organic solvent.

[0009] Further preferred formulation: 85wt%–95wt% of rigid monomers containing double bonds, 1wt%–5wt% of rigid compounds containing thiol groups, 1wt%–5wt% of photoinitiator, and 0wt%–1wt% of organic solvent.

[0010] The rigid monomer containing the double bond is selected from one or a mixture of the following substances: styrene, divinylbenzene, 4-vinylpyridine, N-vinylpyrrolidone, 2,4,6-trienylpropoxy-1,3,5-triazine, 1,4-cyclohexanediethanol divinyl ether, benzyl methacrylate, phenyl methacrylate, benzyl acrylate, phenyl acrylate, isobornyl acrylate, glycidyl methacrylate, glycidyl acrylate, 2-naphthyl acrylate, trimethylsilane acrylate, 2-phenoxyethyl acrylate, glucose acrylate, allyl phenyl ether, acetone glyceryl acrylate, acetone glyceryl methacrylate, styrene acrylate, phenethyl methacrylate, trifluoromethylphenyl acrylate, dicyclopentadiene acrylate, 1-acryloyloxyadamantane, o-phenylphenoxyethyl acrylate, diallyl isophthalate, 1,3,5-benzenetricarboxylic acid triallyl acrylate, p-phenylene Diethylene glycol diacrylate, diethylene glycol diacrylate, diethylene glycol isophthalate, diethylene glycol dimethacrylate, diethylene glycol dimethacrylate, diethylene glycol dimethacrylate, diethylene glycol dimethacrylate, diethylene glycol dimethacrylate, dipropylene glycol diacrylate, dipropylene glycol diacrylate, dipropylene glycol diacrylate, dipropylene glycol diacrylate, dibutylene glycol diacrylate, dibutylene glycol diacrylate, dibutylene glycol diacrylate, cyclohexanedimethyl ester, cyclohexanedimethyl dimethacrylate, bisphenol A glyceryl ester, N-hydroxysuccinimide acrylate, pyrrole acrylate, thiophene acrylate, and more preferably, one or more of cyclohexanedimethyl dimethacrylate, bisphenol A glyceryl ester, diethylene glycol diacrylate, and acetone glyceryl methacrylate.

[0011] The thiol-containing rigid compound is selected from one or a mixture of the following substances: 2,6-naphthyldithiol, 4,4'-dimercaptodiphenyl ether, 4,4'-thiodiphenylthiol, dimercaptothiadiazole, tetramercaptobenzene, biphenyl-4,4'-dithiol, 1,3,5-benzenetrithiophenol, trimercaptotriazine, 2,7-naphthyldithiol, 1,5-dimercaptonaphthalene, 2,2'-dimercaptobiphenyl, 2,5-dimercaptobenzene, 4,4'-dimercaptostilbene, 2,2'-dimercaptobipyridine, 2,5-dimercaptopyrazole, dimercaptoacetylbenzene, 2,6-dimercaptothiophene, 3,5-dimercapto-1,2,4-triazine, dimercaptosilane, 2,6-dimercaptopyridine, and more preferably one or more of tetramercaptobenzene and 1,3,5-benzenetrithiophenol.

[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, bibenzoyl, benzophenone, methyl o-benzoyl, 2-hydroxy-4-(2-hydroxyethoxy)-2-methylphenylpropanone, 2-isopropyl-thioxanth-9-one, 4-phenylbenzophenone, methyl α-oxophenylacetate, 2-hydroxy-2-methylphenylpropane-1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholin-1-propanone, and 2,2-dimethoxyphenylacetophenone. More preferably, one or more of 2-methyl-1-(4-methylthiophenyl)-2-morpholin-1-propanone and 2-hydroxy-2-methylphenylpropane-1-one are preferred.

[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, and more preferably acetone or propylene glycol methyl ether acetate.

[0014] The organic solvent is a selective component. When the composition of the nanoimprint photoresist meets the requirements of inkjet printing and imprinting, or when the addition of the organic solvent will affect the final imprinting effect, the organic solvent may not be added.

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

[0016] Step 1: Mix the rigid monomer containing double bonds, the rigid compound containing thiol groups, the photoinitiator and the organic solvent, stir and mix evenly under light-protected conditions, and filter to obtain nanoimprint photoresist.

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

[0018] 0.2–1 mL of tackifier is dropped onto the silicon wafer that has been vacuum-adsorbed in a spin coater. After spin coating is complete, the silicon wafer with tackifier is transferred to a hot plate for baking. After baking, it is removed and cooled to room temperature for later use. The silicon wafers treated with this tackifier step are referred to as substrates.

[0019] Step 3: Inject 1-2 mL of the nanoimprint photoresist obtained in Step 1 into the ink cartridge of the inkjet printer. Then connect the ink cartridge to the inkjet printer interface, set the desired inkjet pattern to droplet array in the program, align the print head with the substrate through the display screen, and after the inkjet printer runs for 5-300 seconds, the corresponding inkjet pattern can be obtained on the substrate.

[0020] Step 4: Transfer the substrate with 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 imprinting voltage of the nanoimprint lithography machine to 1-10 volts so that the mold moves down and contacts the droplet array on the substrate. After the nanoimprint photoresist fully fills the gaps in the mold, turn on the ultraviolet light to cure it. After curing is complete, turn off the ultraviolet light and remove it from the mold.

[0021] In step 1, the filter used for filtration has a pore size of 0.2 to 2 μm.

[0022] In step 1, the viscosity of the obtained nanoimprint photoresist is 1 to 20 centipoise, preferably 7 to 10 centipoise.

[0023] In step 2, the tackifier is a mixture of propyl 3-trimethoxysilane acrylate, propylene glycol methyl ether acetate and acetone, with a mass ratio of 0.5-2g: 0.5-1.5g: 0.1-0.5g.

[0024] In step 2, the spin coater speed is set to 1000-3000 rpm and the spin coating time is set to 30-90 seconds.

[0025] In step 2, the baking temperature is 50-150℃ and the baking time is 1-2 minutes.

[0026] In step 3, the inkjet printing area is preferably 1 to 50 mm². 2 Further preferred size: 1-25mm 2The 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 spacing is preferably 10–100 μm, more preferably 70–100 μm; the printhead temperature is preferably 20–60 °C, more preferably 20–30 °C; and the substrate temperature is preferably 20–90 °C, more preferably 20–30 °C.

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

[0028] The preparation of test strips and characterization of the mechanical properties of the nanoimprint photoresist of this invention include the following steps:

[0029] (1) Take 0.5-1 mL of the nanoimprint photoresist prepared above, 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 cutout area containing the nanoimprint photoresist 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 attached to the nanoimprint photoresist in the square cutout and air bubbles are eliminated. Turn on the ultraviolet light for curing. The power of the ultraviolet light is 50-110mW and the irradiation time is 60-300s. After curing is completed, turn off the ultraviolet light and remove it from the quartz. Then carefully peel off the cured nanoimprint photoresist.

[0031] (3) Using a 2mm×35mm type 4 cutter conforming to GB / T 528-2009 standard, the nanoimprint photoresist cured in the above steps is cut to obtain a standard dumbbell-shaped template.

[0032] (4) Use the above standard dumbbell-shaped spline to perform stress-strain tests on a universal tensile tester at a tensile rate of 5 mm / min.

[0033] The nanoimprint photoresist of the present invention has a Young's modulus of 0.001 to 1.5 GPa, more preferably 0.8 to 1.2 GPa; a tensile strength of 0.5 to 35 MPa, more preferably 10 to 35 MPa; and a tensile strain of 1 to 50%, more preferably 5 to 15%.

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

[0035] (1) Low viscosity (liquid phase, 7-10 centipoise) at room temperature can be quickly distributed by inkjet printhead and then rapidly cured and imprinted on nanoimprint lithography machine (10s), which to a certain extent effectively solves the compatibility problem between inkjet printing technology and nanoimprint technology.

[0036] (2) After curing, it leaves virtually no residue on the mold, can be released from the mask and preferably adheres to the substrate, thus avoiding pattern defects and repetitive defects in subsequent imprinting.

[0037] (3) Antioxidant polymerization, ensuring complete curing of nanoimprint photoresist, reducing microstructure defects and improving pattern accuracy.

[0038] (4) High mechanical strength ensures the accuracy of pattern replication and high resolution of embossed pattern during curing process (≤50nm). Attached Figure Description

[0039] Figure 1 shows an inkjet-printed pattern of a representative nanoimprint photoresist PR-2.

[0040] Figure 2 shows the apparatus (a) for preparing nanoimprint photoresist and a graph (b) of a standard dumbbell-shaped spline.

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

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

[0043] Figure 5 shows the stress-strain curve 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 Implementation

[0046] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings, but the implementation of the present invention is not limited thereto. The implementation conditions used in the embodiments may be further adjusted as needed, and the implementation conditions not specified are generally those in conventional experiments.

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

[0048] Example 1:

[0049] In this embodiment, a high-mechanical-strength and high-resolution nanoimprint photoresist (nanoimprint photoresist PR-1) is obtained by uniformly mixing the components according to Formula 1. The formula is shown in Table 1 below.

[0050] Table 1. Formulation of a high-mechanical-strength and high-resolution nanoimprint photoresist (Formulation 1)

[0051] Example 2:

[0052] In this embodiment, a high-mechanical-strength and high-resolution nanoimprint photoresist (nanoimprint photoresist PR-2) is obtained by uniformly mixing the components according to Formula 2. The formula is shown in Table 2 below.

[0053] Table 2. Formulation of a high-mechanical-strength and high-resolution nanoimprint photoresist (Formulation 2)

[0054] Example 3:

[0055] In this embodiment, a high-mechanical-strength and high-resolution nanoimprint photoresist (nanoimprint photoresist PR-3) is obtained by uniformly mixing the components according to Formula 3. The formula is shown in Table 3 below.

[0056] Table 3. Formulation of a high-mechanical-strength and high-resolution nanoimprint photoresist (Formulation 3)

[0057] Example 4:

[0058] The difference between Example 4 and Example 2 is that 1,4-cyclohexanediethanol diethylene ether is used instead of cyclohexanediethanol dimethacrylate, and benzyl methacrylate is used instead of acetone glyceryl methacrylate. The resulting formulation is called nanoimprint photoresist PR-4.

[0059] Example 5:

[0060] The difference between Example 5 and Example 2 is that divinylbenzene is used to replace cyclohexanediethanol dimethacrylate and diethylene glycol diacrylate in the components. The resulting formulation is called nanoimprint photoresist PR-5.

[0061] Example 6:

[0062] The difference between Example 6 and Example 2 is that diallyl isophthalate is used instead of cyclohexanediethanol dimethacrylate and diethylene glycol diacrylate in the composition. The resulting formulation is called nanoimprint photoresist PR-6.

[0063] Example 7:

[0064] The difference between Example 7 and Example 2 is that 2,4,6-trienylpropoxy-1,3,5-triazine is used to replace cyclohexanedimethylethanol dimethacrylate and diethylene glycol isophthalate diacrylate in the components. The resulting formulation is called nanoimprint photoresist PR-7.

[0065] Example 8:

[0066] After preparing the nanoimprint photoresist according to each formulation in Examples 1-7, the viscosity was tested using a rotational viscometer. The volume of nanoimprint photoresist used for each formulation was 6-7 mL. The parameters of the viscometer were set as follows: rotor type 18#, rotation speed 90 rpm, test temperature 25℃, and test time 30 s. The viscosity value was recorded after the test.

[0067] Table 4 shows the viscosity values ​​of the nanoimprint photoresists prepared in Examples 1-7.

[0068] Example 9:

[0069] After preparing the nanoimprint photoresist according to the formulations in Examples 1-7, it was used according to the following steps:

[0070] (1) Clean the substrate. The silicon wafer is ultrasonically treated in acetone, isopropanol and water for 10 minutes in sequence, and then treated with oxygen plasma for 2 minutes.

[0071] (2) The silicon wafers were subjected to an adhesion-enhancing treatment. First, an adhesion enhancer was prepared by mixing propyl 3-trimethoxysilane acrylate, propylene glycol methyl ether acetate, and acetone in a mass ratio of 1g:0.75g:0.1g. 0.5mL of the adhesion enhancer was dropped onto the silicon wafer that had been adsorbed and fixed in step (1) in a spin coater. The spin coater parameters were set to 2000 rpm and 45s. After the spin coater was completed, the silicon wafer coated with the adhesion enhancer was removed and transferred to a hot plate for baking at 120°C for 2 minutes. After baking was completed, the treated silicon wafer was removed and cooled to room temperature for later use (the silicon wafer treated with adhesion enhancer is referred to as the substrate).

[0072] (3) Filter 1.5 mL of the prepared nanoimprint photoresist and inject it into the ink cartridge of the inkjet printer. The filter pore size is 0.2 μm. Then, connect the ink cartridge containing the nanoimprint photoresist to the inkjet printer interface, set the inkjet pattern to droplet array, and set the inkjet printing area to 2 mm². 2 The inkjet voltage is 25 volts, the inkjet air pressure is 1 psi, the inkjet frequency is 5000 Hz, the inkjet dot pitch is 80 μm, the printhead temperature is 25°C, and the substrate temperature is 25°C. Align the printhead with the center of the substrate using the operation display. After the inkjet printer has been running for 30 seconds, a printhead with an area of ​​2 mm² will be obtained on the substrate.2 The inkjet pattern was 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 volts for alignment, so that the quartz mold directly above the substrate moves down and contacts the droplet array on the substrate. After the nanoimprint photoresist has fully filled the gaps in the mold, turn on the ultraviolet light for curing. The power of the ultraviolet light is 110mW and the irradiation time is 10s or 30s. After curing is completed, turn off the ultraviolet light and click the "demolding" button to remove it from the mold.

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

[0075] Table 5 shows the effects of the nanoimprint photoresists prepared in Examples 1-7 after inkjet curing.

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

[0077] The purpose of this embodiment is to illustrate,

[0078] ① Observe the inkjet pattern under a microscope (Figure 1). The viscosity of the nanoimprint photoresist is 7-10 centipoise, the inkjet voltage is 25 volts, the inkjet air pressure is 1 pound force / square inch, the inkjet frequency is 5000 Hz, the inkjet droplet diameter is 40 μm, the inkjet droplet spacing is 80 μm, the printhead temperature is 25℃, and the substrate temperature is 25℃. Under these conditions, a relatively uniform droplet array can be printed by inkjet printing.

[0079] ② Nanoimprint photoresist can be completely cured (without liquid film residue) in a very short exposure time. This is attributed to the rapid free radical polymerization reaction during the polymerization process and the antioxidant and polymerization inhibition effect provided by thiols.

[0080] ③ The acrylate double bond components contained in the tackifier may participate in the photocuring process of the nanoimprint photoresist. Therefore, during the demolding process, the nanoimprint photoresist selectively remains on the substrate side, leaving almost no residue on the mold, thus ensuring the cleanliness of the mold.

[0081] Example 10:

[0082] After preparing the nanoimprint photoresist according to the formulations in Examples 1-3, standard dumbbell-shaped samples of the nanoimprint photoresist were prepared for mechanical property testing according to the following steps:

[0083] (1) Take 0.6 mL of nanoimprint photoresist prepared according to each formulation in Examples 1 to 3, 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 mm and a thickness of 200 μm as shown in Figure 2a. The silicon wafer in Figure 2a has been treated with adhesive bonding according to step (2) in Example 9.

[0084] (2) Move the square cutout device containing nanoimprint photoresist directly below 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 adheres tightly to the liquid nanoimprint photoresist in the square cutout, and fully removes air bubbles. Turn on the ultraviolet light to cure it. The power of the ultraviolet light is 110mW and the irradiation time is 300s. After curing is completed, turn off the ultraviolet light, click the "demolding" button to remove the quartz, and then carefully peel off the nanoimprint photoresist.

[0085] (3) Using a 2mm×35mm type 4 cutter conforming to GB / T 528-2009 standard, the nanoimprint photoresist in the above steps is cut to obtain a standard dumbbell-shaped strip as shown in Figure 2b.

[0086] (4) Use the above standard dumbbell-shaped specimens to perform stress and strain tests on a universal tensile tester at a tensile rate of 5 mm / min. Each formulation should be tested at least three times.

[0087] The stress-strain test results of the standard dumbbell-shaped specimens prepared in Examples 1-3 are shown in Figures 3-5. Since the photocuring effect of the nanometer imprinted photoresist in Examples 4-7 was poor, no further research on its mechanical properties was conducted.

[0088] Table 6. Mechanical properties of the standard dumbbell-shaped specimens prepared in Examples 1-3

[0089] Example 11:

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

[0091] As shown in Table 6 and Figure 3, when organic solvents are added as viscosity modifiers to the formulation of nanoimprint photoresist, even a small amount of solvent results in extremely low mechanical strength for nanoimprint photoresist PR-1. This may be because small solvent molecules interfere with and destroy the original crosslinking points, and weaken the inter-chain interactions after penetrating into the polymer chains, thereby reducing the tightness of the crosslinked network. With the relaxation of the crosslinked structure, the rigidity of the material decreases significantly, leading to a sharp deterioration in mechanical properties.

[0092] Example 12:

[0093] The purpose of this embodiment is to illustrate the effect of changing the amount of photoinitiator in the nanoimprint photoresist formulation on the mechanical properties of the nanoimprint photoresist.

[0094] Analyzing Table 6, Figure 4, and Figure 5, when the amount of photoinitiator in the nanoimprint photoresist PR-3 is increased to twice that of PR-2, the Young's modulus and tensile strength of PR-3 decrease to approximately half that of PR-2 under the same exposure time. This is likely because excessive photoinitiator leads to an excessively rapid crosslinking reaction rate, resulting in an uneven crosslinking process and the formation of an irregular crosslinked network structure. This uneven crosslinked network affects the mechanical properties of the material, leading to a significant decrease in its Young's modulus and tensile strength.

[0095] Example 13:

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

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

[0098] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the embodiments described above. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A nanoimprint resist with high mechanical strength and high resolution, characterized in that Its raw materials are composed of the following by mass percentage: Rigid monomers containing double bonds: 50 wt%–95 wt%; rigid compounds containing thiol groups: 0 wt%–20 wt%; photoinitiators: 1 wt%–20 wt%; organic solvents: 0 wt%–20 wt%.

2. The nanoimprint photoresist of claim 1, wherein Its raw materials are composed of the following by mass percentage: The composition includes 80 wt% to 95 wt% rigid monomers containing double bonds, 1 wt% to 10 wt% rigid compounds containing thiol groups, 1 wt% to 10 wt% photoinitiator, and 0 wt% to 15 wt% organic solvent.

3. The nanoimprint photoresist according to claim 1, characterized in that: The rigid monomer containing the double bond is selected from one or a mixture of the following substances: styrene, divinylbenzene, 4-vinylpyridine, N-vinylpyrrolidone, 2,4,6-trienylpropoxy-1,3,5-triazine, 1,4-cyclohexanediethanol divinyl ether, benzyl methacrylate, phenyl methacrylate, benzyl acrylate, phenyl acrylate, isobornyl acrylate, glycidyl methacrylate, glycidyl acrylate, 2-naphthyl acrylate, trimethylsilane acrylate, 2-phenoxyethyl acrylate, glucose acrylate, allyl phenyl ether, acetone glyceryl acrylate, acetone glyceryl methacrylate, styrene acrylate, phenethyl methacrylate, trifluoromethylphenyl acrylate, dicyclopentadiene acrylate, 1-acryloyloxyadamantane, o-phenylphenoxyethyl propylene. Acrylates, diallyl isophthalate, 1,3,5-benzenetricarboxylic acid triallyl, diethylene glycol diacrylate, diethylene glycol diacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, dipropylene glycol diacrylate, dipropylene glycol diacrylate, dipropylene glycol diacrylate, dipropylene glycol diacrylate, dibutylene glycol diacrylate, dibutylene glycol diacrylate, dibutylene glycol diacrylate, cyclohexanedimethyl ester, cyclohexanedimethyl dimethacrylate, bisphenol A glyceryl ester, N-hydroxysuccinimide acrylate, pyrrole acrylate, thiophene acrylate.

4. The nanoimprint photoresist according to claim 1, characterized in that: The thiol-containing rigid compound is selected from one or a mixture of the following substances: 2,6-naphthyldithiol, 4,4'-dimercaptodiphenyl ether, 4,4'-thiodiphenylthiol, dimercaptothiadiazole, tetramercaptobenzene, biphenyl-4,4'-dithiol, 1,3,5-benzenetrithiophenol, trimercaptotriazine, 2,7-naphthyldithiol, 1,5-dimercaptonaphthalene, 2,2'-dimercaptobiphenyl, 2,5-dimercaptobenzene, 4,4'-dimercaptostilbene, 2,2'-dimercaptobipyridine, 2,5-dimercaptopyrazole, dimercaptoacetylbenzene, 2,6-dimercaptothiophene, 3,5-dimercapto-1,2,4-triazacyclohexanes, dimercaptosilane, and 2,6-dimercaptopyridine.

5. The nanoimprint photoresist according to claim 1, characterized in that: The thiol-containing rigid compound is selected from one or more of tetramercaptobenzene and 1,3,5-benzenetrithiophenol.

6. The nanoimprint photoresist according to claim 1, characterized in that: 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, bibenzoyl, benzophenone, methyl o-benzoyl, 2-hydroxy-4-(2-hydroxyethoxy)-2-methylphenylpropanone, 2-isopropyl-thioxanth-9-one, 4-phenylbenzophenone, methyl α-oxophenylacetate, 2-hydroxy-2-methylphenylpropane-1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, and 2,2-dimethoxyphenylacetophenone.

7. The inkjet printing method of the nanoimprint resist according to any one of claims 1 to 6, characterized by Includes the following steps: Step 1: Mix the rigid monomer containing double bonds, the rigid compound containing thiol groups, the photoinitiator and the organic solvent, stir and mix evenly under light-protected conditions, and filter to obtain nanoimprint photoresist; Step 2: Apply adhesive bonding treatment to 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 cartridge to the inkjet printer interface, set the desired inkjet pattern to droplet array in the program, align the print head with the substrate through the display screen, and after the inkjet printer runs for 5-300 seconds, the corresponding inkjet pattern can be obtained on the substrate. Step 4: Transfer the substrate with 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 imprinting voltage of the nanoimprint lithography machine to 1-10 volts so that the mold moves down and contacts the droplet array on the substrate. After the nanoimprint photoresist fully fills the gaps in the mold, turn on the ultraviolet light to cure it. After curing is complete, turn off the ultraviolet light and remove it from the mold.

8. The inkjet printing method according to claim 7, characterized in that: In step 1, the viscosity of the obtained nanoimprint photoresist is 1 to 20 centipoise.

9. The inkjet printing method according to claim 7, characterized in that: In step 2, the thickening treatment includes the following steps: 0.2-1 mL of tackifier is dropped onto the silicon wafer that is vacuum-adsorbed in the spin coater. After spin coating is completed, the silicon wafer with tackifier is transferred to the hot plate for baking. After baking is completed, it is taken out and cooled to room temperature for later use. The tackifier is a mixture of propyl 3-trimethoxysilane acrylate, propylene glycol methyl ether acetate, and acetone.

10. The inkjet printing method according to claim 7, characterized in that: 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 psi, the inkjet frequency is 500-7000 Hz, the inkjet droplet diameter is 10-50 μm, the inkjet droplet pitch is 10-100 μm, the inkjet head temperature is 20-60 °C, and the substrate temperature is 20-90 °C.

Images