Transfer seal for photoresist nano structure, manufacturing method and curved surface photoetching method

Abstract

The invention provides a transfer printing seal for a photoresist nano structure, a manufacturing method and a curved surface photoetching method, and the transfer printing seal comprises the following components in percentage by mass: 40%-70% of N, N-dimethylacrylamide, 30%-60% of 4-hydroxybutyl acrylate, 0.5%-2% of polyethylene glycol diacrylate and 0.5%-2% of a photoinitiator. In the curved surface photoetching process, the transfer printing seal is heated to 90 DEG C and then is conformally attached to the upper surface of the photoresist nano-structure, and the high modulus of the transfer printing seal protects the photoresist nano-structure from being damaged and deformed; the surface of the curved surface is heated, the transfer printing seal with the photoresist nanostructure is heated to 90 DEG C and then is attached to the surface of the curved surface in a conformal mode, the transfer printing seal is slowly peeled off at a constant speed, the reversible high adhesion switching ratio and the high modulus switching ratio can be achieved under thermal stimulation, high-yield picking and releasing of the microstructure are achieved, the transferred microstructure can be protected in the transfer printing picking stage, and the yield of the microstructure is improved. And in the transfer printing release stage, the photoresist nano-structure can be fully attached and conformal with the curved surface, so that high-yield preparation of the photoresist nano-structure on the curved surface is realized.

Description

Technical Field

[0001] This invention relates to the field of micro-nano manufacturing, and in particular provides a transfer stamp for photoresist nanostructures, a manufacturing method thereof, and a curved surface photolithography method. Background Technology

[0002] With the rapid development of emerging fields such as displays, solar cells, and nanoantennas, the demand for curved electronics is growing, demonstrating enormous application potential. Achieving high-precision, high-efficiency, and low-cost manufacturing of curved electronics has become a key challenge. Currently, technologies used for curved electronics manufacturing mainly include direct processing technologies such as jet printing, inkjet printing, laser direct writing, and 3D printing. However, these technologies generally suffer from low manufacturing precision, cumbersome processes, long processing times, or high costs, making it difficult to meet the manufacturing requirements of high-precision, highly integrated, and high-performance curved electronic devices.

[0003] Photolithography, benefiting from its extremely high processing precision (currently reaching sub-10 nanometer nodes) and large-scale production capabilities, is considered the leading technology for manufacturing high-precision, complex micro- and nano-structures, playing an irreplaceable role in the fabrication of planar devices. Applying it to curved surfaces holds promise for solving the high-precision manufacturing challenges of curved electronics. However, traditional photolithography is essentially a planar process, and its key steps, such as photoresist spin coating, exposure, and development, are difficult to directly adapt to the three-dimensional morphology of curved substrates. Existing curved lithography solutions, such as the invention patent (CN111077741A) which proposes a curved lithography machine using a multi-axis mechanical motion module to achieve laser tracking, focusing, and exposure on a curved surface, and another invention patent (CN111077741A) which proposes a curved lithography method using DMD and liquid crystal modulation, achieves multi-degree-of-freedom curved lithography by introducing DMD and liquid crystal to jointly modulate the beam. However, these methods still suffer from high process complexity, specific equipment requirements, and poor compatibility with traditional planar lithography processes, limiting their widespread application and industrialization capabilities.

[0004] To overcome the incompatibility between curved substrates and standard photolithography processes, transfer printing, as an emerging heterogeneous integration technology, presents a highly promising solution. The specific process flow for transfer printing is as follows: first, high-precision micro / nano structures are fabricated on a rigid donor substrate using mature planar photolithography. Then, these structures are picked up from the donor substrate and precisely released onto a receiving substrate of arbitrary shape (including curved or flexible substrates) using a transfer stamp. The key to successful microstructure transfer printing lies in the precise and dynamic control of the stamp's interfacial adhesion characteristics and bulk mechanical properties, enabling it to adapt to two crucial and opposite stages. When picking up planar microstructures, the stamp needs strong adhesion (ensuring microstructure pickup) and high modulus (protecting the microstructure and preventing deformation); during release, the stamp needs weak adhesion (ensuring microstructure release) and low modulus (ensuring the stamp can achieve large-area perfect conformal contact with complex curved surfaces, thus achieving complete microstructure release). Currently reported stamp materials mainly include polydimethylsiloxane, thermal release tape, hydrogels, shape memory polymers, and photosensitive polymers. However, existing seals still face the following challenges in meeting the aforementioned dynamic control requirements and curved surface application scenarios.

[0005] First, the existing stamps have insufficient adhesion switching capabilities, resulting in insufficient adhesion during the pickup stage (unable to pick up microstructures) or excessive adhesion during the release stage (unable to release microstructures), which severely restricts the transfer success rate.

[0006] Second, the mechanical properties of existing seals are limited, especially during the peeling process in the picking stage. They cannot simultaneously meet the high modulus required to protect the microstructure and the low modulus required in the release stage. Large stress is easily generated during the peeling process, which can damage or even destroy the high-precision micro-nano structure, leading to the failure of subsequent device functions.

[0007] Third, existing stamps have poor conformal capabilities to curved surfaces, making it difficult to achieve both low modulus and high tensile strength. This results in insufficient conformity to curved surfaces, leading to problems such as release difficulties, misalignment, and deformation, and making it impossible to achieve precise curved surface lithography. Summary of the Invention

[0008] Based on this, the present invention provides a transfer stamp for photoresist nanostructures, a manufacturing method thereof, and a curved surface photolithography method. The transfer stamp, under thermal stimulation, can achieve a reversible high adhesion switching ratio and a high modulus switching ratio, thereby meeting the requirements for high-yield pickup and controllable release of microstructures. During the transfer pickup stage, the transfer stamp is in a high-modulus state, which effectively supports and protects the microstructure being transferred, preventing stress concentration caused by tensile strain of the transfer stamp and resulting in microstructure damage. During the transfer release stage, the transfer stamp switches to a low-modulus state, allowing it to fully conform to the curved surface, ensuring good contact and stable transfer between the microstructure and the target curved surface. Thus, high-yield fabrication of photoresist nanostructures on curved surfaces can be achieved.

[0009] In a first aspect, the present invention provides a transfer stamp for photoresist nanostructures, comprising, by weight percentage: 40%-70% N,N-dimethylacrylamide, 30%-60% 4-hydroxybutyl acrylate, 0.5%-2% polyethylene glycol diacrylate, 0.5%-2% photoinitiator; Preferably, the polyethylene glycol diacrylate has an average molecular weight of at least one of 200, 400, 600, 1000, 2000, 4000, 6000, and 10000.

[0010] Preferably, the photoinitiator is at least one of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphine, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, lithium phenyl(2,4,6-trimethylbenzoyl)phosphate, 2-isopropylthioxanthone, 2,4-diethylthiazolinone, 2-ethylanthraquinone, tetraethylmielone, and bis(2,6-difluoro-3-pyrrolephenyldicyclopentadiene).

[0011] Secondly, the present invention provides a method for manufacturing a transfer stamp for photoresist nanostructures, comprising the following steps: S110. Weigh a certain mass of N,N-dimethylacrylamide, 4-hydroxybutyl acrylate, polyethylene glycol diacrylate, and photoinitiator into a beaker, stir at room temperature for 1-2 hours to obtain a uniform transfer stamp precursor resin; S120. Vacuum in the dark until no air bubbles remain in the precursor resin; S130. Pour the resin into a mold (such as polytetrafluoroethylene, silicone, etc.) or coat it directly onto a rigid substrate (such as silicon, silica, etc.); S140. After irradiating with ultraviolet light for 0.5-3 minutes, cool to room temperature to obtain the transfer stamp.

[0012] Thirdly, the present invention provides a photolithography method for curved surfaces of photoresist nanostructures, comprising the following steps: S210. Provides a hard wafer substrate, the substrate is hydrophobically treated, a photoresist precursor solution is spin-coated on the substrate, a photoresist film is obtained by pre-baking, and the patterning of the photoresist nanostructure is completed by exposure and post-baking. S220. After heating the transfer stamp to 90°C, it is conformally attached to the upper surface of the photoresist nanostructure. Pressure is applied and maintained until the stamp cools to room temperature to achieve the pickup of the photoresist nanostructure. During the separation of the photoresist from the hard wafer substrate, the high modulus of the transfer stamp protects the photoresist nanostructure from damage and deformation. S230. Heat the curved surface, heat the transfer stamp with photoresist nanostructure to 90°C and conformally attach it to the curved surface, slowly and uniformly peel off the transfer stamp to separate the stamp from the photoresist structure and release the photoresist nanostructure. S240. Develop the photoresist in a photoresist developer to obtain a photoresist nanostructure on the curved surface.

[0013] Preferably, the hard wafer substrate is at least one of silicon, silicon dioxide, lithium niobate, and a metal substrate.

[0014] Preferably, the hydrophobic treatment method includes one of the following: the substrate is exposed to an HMDS atmosphere for 30 minutes at a temperature of 120°C; or the substrate is exposed to an OTS atmosphere for 10 minutes at a temperature of 105°C.

[0015] Preferably, the photoresist precursor solution is one of optical i-line positive photoresist, optical i-line negative photoresist, electron beam photoresist, and nanoimprint stencil.

[0016] Preferably, the spin coating speed is 2000-8000 rpm.

[0017] Preferably, the pre-drying and post-drying temperatures are 60-300℃, and the time is 1-5 minutes.

[0018] Preferably, the exposure method is at least one of contact mask exposure, perfect contact exposure, proximity mask exposure, projection mask exposure, laser direct writing exposure, electron beam exposure, and nanoimprinting.

[0019] Preferably, the developer is at least one of an inorganic developer and an organic developer.

[0020] The present invention provides a transfer stamp for photoresist nanostructures, a manufacturing method thereof, and a curved surface photolithography method. The technical advantages are at least reflected in the following aspects: Firstly, the provided transfer stamp and manufacturing method have an extremely high adhesion switching ratio, ensuring high-yield pickup and controllable release of photoresist nanostructures; and have an extremely high modulus switching ratio, being in a high modulus state during the transfer pickup stage, which can effectively support and protect the microstructure being transferred, avoiding stress concentration caused by the tensile strain of the transfer stamp and resulting in damage to the microstructure; and being in a low modulus state during the transfer release stage, which can perfectly conform to the curved substrate, ensuring good contact and stable transfer between the microstructure and the target curved surface. Secondly, the provided curved surface photolithography method adopts a post-development process, which can effectively prevent the photoresist microstructure from undergoing deformation, displacement and other failure modes on the curved surface, ensuring the curved surface fabrication of high-precision microstructures. It provides a high-precision, high-yield, efficient and process-compatible curved electronic fabrication method, which has great potential in curved surface applications. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a flowchart of a photolithography method for photoresist nanostructures on curved surfaces.

[0023] Figure 2 The graph shows the changes in the adhesion properties of the stamps in Examples 1, 2, 3, and 4. In the graph, DMAA is N,N-dimethylacrylamide.

[0024] Figure 3 The graph shows the changes in the modulus properties of the stamps in Examples 1, 2, 3, and 4. In the graph, DMAA stands for N,N-dimethylacrylamide.

[0025] Figure 4 This is a microscopic image of the morphology of the photoresist micro / nano structure transferred to the spherical surface using the transfer stamp in Example 1. The spherical diameter is 25 mm, the photoresist structure is a lattice structure with a diameter of 1 μm, and the transfer yield is 100% (170 in total).

[0026] Figure 5 This is a microscopic image of the morphology of the micro / nano structure of photoresist transferred to the cylindrical curved surface using the transfer stamp in Example 1. The cylinder diameter is 25 mm, and the photoresist structure is an array of photoresist holes with a diameter of 1 μm.

[0027] Figure 6 This is a microscopic image of the morphology of the photoresist micro / nano structure transferred to the concave curved surface using the transfer stamp in Example 1. The concave surface has a diameter of 35 mm, and the photoresist structure is a grating structure with a linewidth of 1 μm.

[0028] Figure 7 This is a micrograph of the morphology of the photoresist nanostructure transferred to the surface of silica microspheres using the transfer stamp in Example 1. The microspheres have a diameter of 100 μm, and the photoresist structure is a periodic lattice with a diameter of 600 nm to 1 μm. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] This invention provides a transfer stamp for photoresist nanostructures, comprising, by weight percentage: 40%-70% N,N-dimethylacrylamide, 30%-60% 4-hydroxybutyl acrylate, 0.5%-2% polyethylene glycol diacrylate, and 0.5%-2% photoinitiator.

[0031] like Figure 1 As shown, the present invention provides S210. A hard wafer substrate is provided, the substrate is hydrophobically treated, a photoresist precursor solution is spin-coated on the substrate, a photoresist film is obtained by pre-baking, and the patterning of the photoresist nanostructure is completed by exposure and post-baking. S220. After heating the transfer stamp to 90°C, it is conformally attached to the upper surface of the photoresist nanostructure. Pressure is applied and maintained until the stamp cools to room temperature to achieve the pickup of the photoresist nanostructure. During the separation of the photoresist from the hard wafer substrate, the high modulus of the transfer stamp protects the photoresist nanostructure from damage and deformation. S230. Heat the curved surface, heat the transfer stamp with photoresist nanostructure to 90°C and conformally attach it to the curved surface, slowly and uniformly peel off the transfer stamp to separate the stamp from the photoresist structure and release the photoresist nanostructure. S240. Develop the photoresist in a photoresist developer to obtain a photoresist nanostructure on the curved surface.

[0032] The provided transfer stamp and curved surface photolithography method for photoresist nanostructures can achieve high adhesion switching ratio and high modulus switching ratio under thermal stimulation, enabling high-yield pickup and release of microstructures and high-yield fabrication of photoresist nanostructures on curved surfaces.

[0033] The following is combined Figures 2 to 7 The embodiments will be described in detail to make the technical solution of the present invention clearer. Example 1

[0034] This embodiment provides a transfer stamp for photoresist nanostructures, comprising the following components by weight percentage: The composition comprises 60% N,N-dimethylacrylamide, 40% 4-hydroxybutyl acrylate, 0.5% polyethylene glycol diacrylate, and 0.5% photoinitiator; wherein the average molecular weight of the polyethylene glycol diacrylate is 600. The photoinitiator is ethyl 2,4,6-trimethylbenzoylphenylphosphonate.

[0035] Manufacturing method: Weigh a certain mass of N,N-dimethylacrylamide, 4-hydroxybutyl acrylate, polyethylene glycol diacrylate, and photoinitiator into a beaker according to the specified proportions. Stir at room temperature for 1 hour to obtain a uniform transfer stamp precursor resin. Vacuum the resin in the dark until no air bubbles remain. Pour the resin into a polytetrafluoroethylene mold, irradiate with ultraviolet light for 1 minute, and then cool to room temperature to obtain the transfer stamp.

[0036] This embodiment provides a photolithography method for curved surfaces with photoresist nanostructures, including the following steps: Step 1: Provide a hard wafer substrate, treat the substrate for hydrophobicity, spin-coat a photoresist precursor solution onto the substrate, pre-bake to obtain a photoresist film, and complete the patterning of the photoresist nanostructure through exposure and post-bake. The hard wafer substrate is silicon; the hydrophobic treatment method is to expose the substrate to an OTS atmosphere for 10 minutes at a temperature of 105°C; the photoresist precursor solution is an optical i-line negative photoresist; the spin-coating speed is 3000 rpm; the pre-bake and post-bake temperatures are 95°C for 3 minutes; and the exposure method is contact mask exposure.

[0037] Step 2: After heating the transfer stamp to 90°C, it is conformally attached to the upper surface of the photoresist nanostructure. Pressure is applied and maintained until the stamp cools to room temperature to pick up the photoresist nanostructure. During the separation of the photoresist from the hard wafer substrate, the high modulus of the transfer stamp protects the photoresist nanostructure from damage and deformation. Step 3: Heat the curved surface, heat the transfer stamp with photoresist nanostructure to 90°C and conformally attach it to the curved surface, slowly and uniformly peel off the transfer stamp to separate the stamp from the photoresist structure and release the photoresist nanostructure. Step 4: Develop the photoresist in a photoresist developer to obtain the photoresist nanostructure on the curved surface. The developer is an organic developer.

[0038] Figure 2 The graph shows the changes in the adhesion properties of the stamps in Examples 1, 2, 3, and 4. Figure 3 The graph shows the changes in the modulus properties of the seals in Examples 1, 2, 3, and 4; from... Figure 2 and Figure 3 It can be demonstrated that the transfer stamp in Specific Embodiment 1 has the largest adhesion switching ratio (~1003) and the largest modulus switching ratio (~6975).

[0039] Figure 4 The image shows the morphology of 170 photoresist dot structures (1 μm in diameter) transferred to a spherical surface (25 mm in diameter) by the transfer stamp in Example 1, demonstrating that the transfer stamp can achieve 100% yield in curved surface transfer.

[0040] Figure 5 The image shows a microscopic image of the morphology of the photoresist micro / nano structure transferred to the cylindrical surface by the transfer stamp in Example 1, proving that the transfer stamp can realize the transfer of photoresist micro / nano structures on a developable surface.

[0041] Figure 6 The image shows a microscopic image of the morphology of the photoresist micro / nano structure transferred to the concave curved surface by the transfer stamp in Example 1, proving that the transfer stamp can realize the transfer of photoresist micro / nano structures on non-developable curved surfaces.

[0042] Figure 7 The image shows a micrograph of the morphology of the photoresist nanostructure transferred to the surface of silica microspheres using the transfer stamp in Example 1. This demonstrates that the transfer stamp can transfer photoresist nanostructures onto surfaces with high curvature that cannot be developed. Similarly, referring to Examples 1-4, it can be seen that the transfer stamp of the present invention has a reversible high adhesion switching ratio and a high modulus switching ratio. Example 2

[0043] This embodiment provides a transfer stamp for photoresist nanostructures, comprising the following components by weight percentage: 40% N,N-dimethylacrylamide, 60% 4-hydroxybutyl acrylate, 1% polyethylene glycol diacrylate, and 1% photoinitiator; the polyethylene glycol diacrylate has an average molecular weight of 400, and the photoinitiator is phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

[0044] Manufacturing method: Weigh a certain mass of N,N-dimethylacrylamide, 4-hydroxybutyl acrylate, polyethylene glycol diacrylate, and photoinitiator into a beaker and stir at room temperature for 1.5 hours to obtain a uniform transfer stamp precursor resin. Vacuum the resin in the dark until no air bubbles remain. Pour the resin into a silicone mold, irradiate with ultraviolet light for 2 minutes, and then cool to room temperature to obtain the transfer stamp.

[0045] This embodiment provides a photolithography method for curved surfaces with photoresist nanostructures, including the following steps: Step 1: Provide a hard wafer substrate, treat the substrate for hydrophobicity, spin-coat a photoresist precursor solution onto the substrate, pre-bake to obtain a photoresist film, and complete the patterning of the photoresist nanostructure through exposure and post-bake; the hard wafer substrate is silicon dioxide. The hydrophobic treatment method involves exposing the substrate to an HMDS atmosphere for 30 minutes at a temperature of 120°C. The photoresist precursor solution is an electron beam photoresist. The spin-coating speed is 7000 rpm. The pre-bake and post-bake temperatures are 180°C for 5 minutes. The exposure method is electron beam exposure.

[0046] Step 2: After heating the transfer stamp to 90°C, it is conformally attached to the upper surface of the photoresist nanostructure. Pressure is applied and maintained until the stamp cools to room temperature to pick up the photoresist nanostructure. During the separation of the photoresist from the hard wafer substrate, the high modulus of the transfer stamp protects the photoresist nanostructure from damage and deformation. Step 3: Heat the curved surface, heat the transfer stamp with photoresist nanostructure to 90°C and conformally attach it to the curved surface, slowly and uniformly peel off the transfer stamp to separate the stamp from the photoresist structure and release the photoresist nanostructure. Step 4: Develop the photoresist in a photoresist developer to obtain the photoresist nanostructure on the curved surface. The developer is an organic developer.

[0047] The transfer stamp, manufacturing method, and curved surface photolithography method for photoresist nanostructures provided in this embodiment can have a reversible high adhesion switching ratio and high modulus switching ratio under thermal stimulation, achieving high-yield pickup and release of microstructures. During the transfer pickup stage, the microstructure being transferred can be protected, and during the transfer release stage, it can fully conform to the curved surface, achieving high-yield fabrication of photoresist nanostructures on curved surfaces. Example 3

[0048] This embodiment provides a transfer stamp for photoresist nanostructures, comprising, by weight percentage: 70% N,N-dimethylacrylamide, 30% 4-hydroxybutyl acrylate, 2% polyethylene glycol diacrylate, and 2% photoinitiator; the polyethylene glycol diacrylate has an average molecular weight of 1000. The photoinitiator is diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide.

[0049] Manufacturing method: Weigh a certain mass of N,N-dimethylacrylamide, 4-hydroxybutyl acrylate, polyethylene glycol diacrylate, and photoinitiator into a beaker and stir at room temperature for 2 hours to obtain a uniform transfer stamp precursor resin. Vacuum the resin in the dark until no air bubbles remain. Coat the resin directly onto a hard silicon substrate, irradiate with ultraviolet light for 0.5 minutes, and then cool to room temperature to obtain the transfer stamp.

[0050] This embodiment provides a photolithography method for curved surfaces with photoresist nanostructures, including the following steps: Step 1: Provide a hard wafer substrate, treat the substrate for hydrophobicity, spin-coat a photoresist precursor solution onto the substrate, pre-bake to obtain a photoresist film, and complete the patterning of the photoresist nanostructure through exposure and post-bake. The hard wafer substrate mentioned in Step 1 is a silicon substrate. The hydrophobic treatment method mentioned in Step 1 involves exposing the substrate to an OTS atmosphere for 10 minutes at a temperature of 105°C. The photoresist precursor solution mentioned in Step 1 is an optical i-line positive photoresist. The spin-coating speed mentioned in Step 1 is 6000 rpm. The pre-bake and post-bake temperatures mentioned in Step 1 are 105°C for 1.5 minutes. The exposure method is proximity mask exposure.

[0051] Step 2: After heating the transfer stamp to 90°C, it is conformally attached to the upper surface of the photoresist nanostructure. Pressure is applied and maintained until the stamp cools to room temperature to pick up the photoresist nanostructure. During the separation of the photoresist from the hard wafer substrate, the high modulus of the transfer stamp protects the photoresist nanostructure from damage and deformation. Step 3: Heat the curved surface, heat the transfer stamp with photoresist nanostructure to 90°C and conformally attach it to the curved surface, slowly and uniformly peel off the transfer stamp to separate the stamp from the photoresist structure and release the photoresist nanostructure. Step 4: Develop the photoresist in a photoresist developer to obtain the photoresist nanostructure on the curved surface. The developer is an inorganic developer.

[0052] The transfer stamp and manufacturing method provided in this embodiment have an extremely high adhesion switching ratio, ensuring the success rate of photoresist nanostructure transfer; and an extremely high modulus switching ratio, with high modulus in the transfer pick-up stage, which can effectively protect the photoresist nanostructure, and low modulus in the transfer release stage, which can perfectly conform to the curved receiving substrate, ensuring the transfer yield; the curved surface photolithography method adopts a post-development process, which can effectively prevent the photoresist microstructure from undergoing deformation, displacement and other failure modes on the curved surface, ensuring the preparation of high-precision microstructures on the curved surface. Example 4

[0053] This embodiment provides a transfer stamp for photoresist nanostructures, comprising, by weight percentage: 50% N,N-dimethylacrylamide, 50% 4-hydroxybutyl acrylate, 1.5% polyethylene glycol diacrylate, and 1.5% photoinitiator; wherein the polyethylene glycol diacrylate has an average molecular weight of 600, and the photoinitiator is 2-isopropylthioxanthion.

[0054] Manufacturing method: Weigh a certain mass of N,N-dimethylacrylamide, 4-hydroxybutyl acrylate, polyethylene glycol diacrylate, and photoinitiator into a beaker and stir at room temperature for 1 hour to obtain a uniform transfer stamp precursor resin. Vacuum the resin in the dark until no air bubbles remain. Pour the resin into a mold or coat it directly onto a hard substrate. Irradiate with ultraviolet light for 0.5 minutes and then cool to room temperature to obtain the transfer stamp.

[0055] This embodiment provides a photolithography method for curved surfaces with photoresist nanostructures, including the following steps: Step 1: Provide a hard wafer substrate, treat the substrate for hydrophobicity, spin-coat a photoresist precursor solution onto the substrate, pre-bake to obtain a photoresist film, and complete the patterning of the photoresist nanostructure through exposure and post-bake; the hard wafer substrate is silicon dioxide. The hydrophobic treatment method involves exposing the substrate to an HMDS atmosphere for 30 minutes at a temperature of 120°C. The photoresist precursor solution is an electron beam photoresist. The spin-coating speed is 8000 rpm. The pre-bake and post-bake temperatures are 180°C for 5 minutes. The exposure method is electron beam exposure.

[0056] Step 2: After heating the transfer stamp to 90°C, it is conformally attached to the upper surface of the photoresist nanostructure. Pressure is applied and maintained until the stamp cools to room temperature to pick up the photoresist nanostructure. During the separation of the photoresist from the hard wafer substrate, the high modulus of the transfer stamp protects the photoresist nanostructure from damage and deformation. Step 3: Heat the curved surface, heat the transfer stamp with photoresist nanostructure to 90°C and conformally attach it to the curved surface, slowly and uniformly peel off the transfer stamp to separate the stamp from the photoresist structure and release the photoresist nanostructure. Step 4: Develop the photoresist in a photoresist developer to obtain the photoresist nanostructure on the curved surface. The developer is an organic developer.

[0057] This embodiment provides a transfer stamp for photoresist nanostructures and a curved surface photolithography method. The transfer stamp is prepared using a photocurable polymer material and exhibits a reversible high adhesion switching ratio under thermal stimulation, enabling high-yield pickup and release of microstructures. The transfer stamp also possesses a reversible high modulus switching ratio under thermal stimulation, protecting the transferred microstructure during the pickup phase and conformally fitting the curved surface during the release phase. By using this transfer stamp, high-yield fabrication of photoresist nanostructures on curved surfaces can be achieved. The curved surface photolithography method of this invention provides a high-precision, high-yield, efficient, and process-compatible means of fabricating curved electronics, possessing great potential in complex curved surface applications.

[0058] This document provides a detailed description and uses specific examples to illustrate the principles and implementation methods of the present invention. The above embodiments are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

[0059] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the system and unit described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

Claims

1. A transfer stamp for photoresist nanostructures, characterized in that, Components by weight percentage include: 40%-70% N,N-dimethylacrylamide, 30%-60% 4-hydroxybutyl acrylate, 0.5%-2% polyethylene glycol diacrylate, and 0.5%-2% photoinitiator.

2. The transfer stamp for photoresist nanostructures according to claim 1, characterized in that, The photoinitiator is at least one of diphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, phenylphosphine dioxide, lithium phenyl phosphate, 2-isopropylthioxanthone, 2,4-diethylthiazolinone, 2-ethylanthraquinone, tetraethylmielone, or bis(2,6-difluoro-3-pyrrolephenyldicarboxylate).

3. A method for manufacturing a transfer stamp for photoresist nanostructures, characterized in that the steps include... include: S110. Weigh a certain amount of N,N-dimethylacrylamide, 4-hydroxybutyl acrylate, polyethylene glycol diacrylate, and photoinitiator into a beaker and stir at room temperature for 1-2 hours to obtain a uniform transfer stamp precursor resin. S120. Vacuum in the dark until no air bubbles remain in the precursor resin; S130. Pour the resin into a mold, or coat it directly onto a rigid substrate; S140. After irradiating with ultraviolet light for 0.5-3 minutes, cool to room temperature to obtain the transfer stamp.

4. A photolithography method for curved surfaces with photoresist nanostructures, using the transfer stamp described in claim 1, 2, or 3, characterized in that, Includes the following steps: S210. Provides a hard wafer substrate, the substrate is hydrophobically treated, a photoresist precursor solution is spin-coated on the substrate, a photoresist film is obtained by pre-baking, and the patterning of the photoresist nanostructure is completed by exposure and post-baking. S220. After heating the transfer stamp to 90°C, it is conformally attached to the upper surface of the photoresist nanostructure. Pressure is applied and maintained until the stamp cools to room temperature to achieve the pickup of the photoresist nanostructure. During the separation of the photoresist from the hard wafer substrate, the high modulus of the transfer stamp protects the photoresist nanostructure from damage and deformation. S230. Heat the curved surface, heat the transfer stamp with photoresist nanostructure to 90°C and conformally attach it to the curved surface, slowly and uniformly peel off the transfer stamp to separate the stamp from the photoresist structure and release the photoresist nanostructure. S240. Develop the photoresist in a photoresist developer to obtain a photoresist nanostructure on the curved surface.

5. The photolithography method for curved surfaces of photoresist nanostructures according to claim 4, characterized in that, The hard wafer substrate is at least one of silicon, silicon dioxide, lithium niobate, or a metal substrate.

6. The photolithography method for curved surfaces of photoresist nanostructures according to claim 4, characterized in that, The hydrophobic treatment method includes one of the following: the substrate is exposed to an HMDS atmosphere for 30 min at a temperature of 120°C; or the substrate is exposed to an OTS atmosphere for 10 min at a temperature of 105°C.

7. The photoresist nanostructure curved surface photolithography method according to claim 4, characterized in that, The photoresist precursor solution is one of optical i-line positive photoresist, optical i-line negative photoresist, electron beam photoresist, or nanoimprint lithography.

8. The photolithography method for curved surfaces of photoresist nanostructures according to claim 4, characterized in that, The spin coating speed is 2000-8000 rpm.

9. The photolithography method for curved surfaces of photoresist nanostructures according to claim 4, characterized in that, The pre-drying and post-drying temperatures are 60-300℃, and the time is 1-5 minutes.

10. The photolithography method for curved surfaces of photoresist nanostructures according to claim 4, characterized in that, The exposure method is at least one of contact mask exposure, perfect contact exposure, proximity mask exposure, projection mask exposure, laser direct writing exposure, electron beam exposure, and nanoimprinting, and the developer is at least one of inorganic developer and organic developer.

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