Method for manufacturing micro- and nanostructures

Abstract

The application discloses a preparation method of a micro-nano structure, and the preparation method comprises the following steps: providing a sub-template, wherein the material of the sub-template is an acrylic material; performing surface activation treatment on a first surface of an imprint structure along a first direction through oxygen plasma, so as to drive C=C double bonds of at least part of the thickness of the imprint structure to be oxidized into carboxyl or the C=C double bonds to be broken; coating an epoxy imprint glue with a set thickness on a substrate surface; imprinting the sub-template on the epoxy imprint glue, so that the first surface of the imprint structure reacts with the epoxy imprint glue to remove the epoxy imprint glue between the first surface and the substrate; curing the epoxy imprint glue after a set reaction time and removing the sub-template, so as to obtain the micro-nano structure. The application eliminates residual glue through spontaneous reaction in the whole process, and improves the consistency of the micro-nano structure.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanoimprinting, and particularly relates to a method for preparing micro-nano structures. Background Art

[0002] Refer Figure 1 As shown, the process of fabricating nanostructures based on nanoimprinting technology generally includes: spin-coating a thin film of imprinting resist with a uniform thickness on a target substrate 30', placing a template 10' that has been subjected to an anti-sticking treatment on the imprinting resist thin film, and applying pressure to fill the imprinting resist into the cavities of the template 10'. After curing the imprinting resist and demolding, an imprinting resist nanostructure replicated 1:1 with the template is obtained. After removing the residual resist layer, using a dry etching process or a wet etching process with the imprinting resist structure as a mask to transfer the template pattern to the target substrate 30', a nanostructure of the substrate material is obtained.

[0003] Due to the inherent characteristics of nanoimprinting, when the nanostructures in the template 10' have different duty cycles or heights, the thickness of the residual resist at each place after imprinting is different. For example Figure 1 in, the thickness of the residual resist layer at the first residual resist region 201' and the second residual resist region 202' is inconsistent. The non-uniformity of the residual resist layer thickness will affect the subsequent structure transfer process. If the residual resist is removed based on the thinner part, the region with thicker residual resist cannot be completely removed. If the residual resist is removed based on the thicker part, the target substrate 30' in the region with thinner residual resist will lose height.

[0004] Therefore, in view of the above technical problems, it is necessary to provide a method for preparing micro-nano structures. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing micro-nano structures, which can eliminate residual resist through a spontaneous reaction throughout the process and improve the consistency of micro-nano structures.

[0006] To achieve the above purpose, the technical solution provided by a specific embodiment of the present invention is as follows:

[0007] A method for preparing micro-nano structures, the preparation method comprising:

[0008] Providing a sub-template, the material of the sub-template being an acrylic material, the acrylic material having a C=C double bond and a carboxyl functional group, the sub-template including a base layer and an imprinting structure protruding from the surface of the base layer, the imprinting structure having a first surface away from the base layer;

[0009] Performing surface activation treatment on the first surface of the imprinting structure along a first direction by oxygen plasma to drive at least a part of the thickness of the C=C double bond of the imprinting structure to be oxidized into carboxyl or the C=C double bond to be broken, the first direction extending from the first surface towards the base layer;

[0010] An epoxy-based imprinting adhesive of a predetermined thickness is coated onto the substrate surface;

[0011] The sub-template is imprinted onto the epoxy imprinting adhesive, and the first surface of the imprinted structure reacts with the epoxy imprinting adhesive to remove the epoxy imprinting adhesive located between the first surface and the substrate;

[0012] After a set reaction time, the epoxy-based imprinting adhesive is cured and the sub-template is removed to obtain a micro / nano structure.

[0013] In one or more embodiments of the present invention, surface activation treatment of the first surface of the imprinted structure is performed by oxygen plasma along a first direction, including:

[0014] Oxygen plasma is injected into the first surface of the imprinted structure along a first direction using an ICP process.

[0015] In one or more embodiments of the present invention, injecting oxygen plasma into the first surface of the imprinted structure along a first direction based on an ICP process includes:

[0016] The oxygen flow rate inside the ICP device is 8~10 sccm, and the oxygen pressure is 70~90 mT;

[0017] The power of the ICP device is 80~100W to ionize the oxygen into oxygen plasma;

[0018] The ICP device has a power of 25~35W to apply the oxygen plasma to the first surface, and the surface treatment time of the ICP device is 20~50s.

[0019] In one or more embodiments of the present invention, the oxygen plasma includes oxygen free radicals, which undergo addition reactions with C=C double bonds and / or directly break the double bonds. After the addition reaction, intermediate products containing hydroxyl or peroxy bonds are generated, and the oxygen free radicals oxidize the intermediate products to aldehyde or carboxyl groups.

[0020] In one or more embodiments of the present invention, the first surface of the imprinted structure reacts with the epoxy imprinting adhesive to remove the epoxy imprinting adhesive located between the first surface and the substrate, including:

[0021] The epoxy imprinting adhesive includes epoxy groups, and the epoxy groups and carboxyl groups within at least a portion of the thickness of the imprinting structure react with the epoxy groups through acid-catalyzed ring-opening to form a three-dimensional cross-linked network.

[0022] In one or more embodiments of the present invention, the set reaction time is 1.5 to 3 minutes.

[0023] In one or more embodiments of the present invention, the thickness of the epoxy imprinting adhesive is 10 nm to 20 μm.

[0024] In one or more embodiments of the present invention, the preparation method further includes: providing a master template, the master template including a first micro-nano structure, and reprinting the master template to obtain the sub-template.

[0025] On the other hand, a micro / nano structure is provided, which is prepared by the method for preparing the micro / nano structure.

[0026] In another aspect, a template for preparing micro / nano structures is provided, the template being made of an acrylic material having C=C double bonds and carboxyl functional groups, the template comprising a base layer and an imprinted structure protruding from the surface of the base layer, the imprinted structure having a first surface remote from the base layer.

[0027] Compared with existing technologies, the micro / nano structure preparation method of the present invention breaks the molecular structure of acrylic acid through surface activation treatment, and generates more carboxyl groups in the components of the imprinted structure of a certain thickness. By using an imprinting adhesive containing epoxy components and a sub-template for imprinting, the imprinted structure undergoes a cross-linking reaction with the epoxy components, allowing the imprinted structure to "absorb" the imprinting adhesive between the first surface and the substrate, achieving zero-residue imprinting without the need for additional steps to remove residue;

[0028] This invention requires no high temperature throughout the process, effectively avoiding the problem of acrylic acid's tendency to self-polymerize due to the presence of double bonds. The entire process is a spontaneous reaction, flexible and controllable, and suitable for micro and nano structures. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the preparation process of the imprinting nanostructure in the existing technology;

[0031] Figure 2a This is a schematic diagram of the sub-template structure in one embodiment of the present invention;

[0032] Figure 2b This is a schematic diagram of the process of imprinting a sub-template onto an epoxy-based imprinting adhesive in one embodiment of the present invention;

[0033] Figure 2cThis is a schematic diagram of the structure after the epoxy imprinting adhesive reacts with the imprinting structure in one embodiment of the present invention;

[0034] Figure 2d This is a schematic diagram of the process of a micro / nano structure (including a substrate) in one embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram of the activation depth of the sub-template in one embodiment of the present invention. Detailed Implementation

[0036] To enable those skilled in the art to better understand the technical solutions in this disclosure, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this disclosure.

[0037] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0038] In the detailed description of this specification, reference is made to the accompanying drawings, which form a part thereof, wherein like reference numerals always denote like parts, and wherein exemplary embodiments are shown by way of example that may be implemented. It should be understood that other embodiments may be utilized, and structural or logical changes may be made, without departing from the scope of this application. Therefore, the following detailed description should not be considered limiting.

[0039] To facilitate understanding of the technical solutions of this application, the technical terms appearing in this invention will be explained in detail below.

[0040] ICP process: This process utilizes a high-frequency electromagnetic field to excite gas to form an inductively coupled plasma (ICP), which is then used to perform etching, deposition, or cleaning of materials. The main steps include: gas ionization (reactive gases (such as CF4 or O2) are introduced into a vacuum chamber, and a high-frequency power supply generates an alternating magnetic field through a coil), plasma formation (magnetic field energy is coupled into the gas, ionizing the gas molecules to form a plasma composed of electrons, ions, and neutral particles), and material processing (depending on requirements, the active particles in the plasma perform etching, thin film deposition, or surface treatment on the substrate material through physical bombardment or chemical reactions).

[0041] As mentioned in the background section, when the nanostructures in the template 10' have different duty cycles or heights, the residual adhesive thickness varies at different locations after imprinting. For example... Figure 1In the process, the thickness of the residual adhesive layer located in the first residual adhesive region 201' and the second residual adhesive region 202' is inconsistent. This unevenness in the residual adhesive layer thickness will affect the subsequent structure transfer process. If the residual adhesive is removed based on the thinner area, the thicker area will not be completely removed. Conversely, if the residual adhesive is removed based on the thicker area, the target substrate 30' in the thinner area will lose height.

[0042] To address the aforementioned technical issues, existing technologies employ spot spraying, which precisely positions and sprays photoresist onto designated areas of the substrate as needed, replacing traditional full-surface coating. The drawback of spot spraying is that when the target micro / nano structure is too small, the volume of a single drop of photoresist is much larger than the space occupied by the nanostructure, still resulting in residual photoresist.

[0043] To address the aforementioned problems, this disclosure provides a method for preparing micro / nano structures. By modifying the surface of the sub-template that contacts the residual adhesive, the reaction between the sub-template and the residual adhesive is promoted to eliminate the residual adhesive, thus achieving uniform control of the residual adhesive. Specifically, the preparation method includes:

[0044] A sub-template is provided. The sub-template is made of acrylic material. The acrylic material has C=C double bonds and carboxyl functional groups. The sub-template includes a base layer and an embossed structure protruding from the surface of the base layer. The embossed structure has a first surface away from the base layer.

[0045] The first surface of the imprinted structure is activated by oxygen plasma along a first direction to drive the oxidation of C=C double bonds in at least a portion of the thickness of the imprinted structure to carboxyl groups or the breakage of C=C double bonds, with the first direction extending from the first surface to the base layer.

[0046] An epoxy-based imprinting adhesive of a predetermined thickness is coated onto the substrate surface;

[0047] The sub-template is imprinted onto an epoxy imprinting adhesive, and the first surface of the imprinted structure reacts with the epoxy imprinting adhesive to remove the epoxy imprinting adhesive located between the first surface and the substrate.

[0048] After setting the reaction time, the epoxy imprinting adhesive is cured and the sub-template is removed to obtain the micro / nano structure.

[0049] Understandably, this disclosure breaks the molecular structure of acrylic acid through surface activation treatment, thereby generating more carboxyl groups in the components of the partially thick imprinted structure. By using an imprinting adhesive containing epoxy components and a sub-template for imprinting, the imprinted structure undergoes a cross-linking reaction with the epoxy components, allowing the imprinted structure to "absorb" the imprinting adhesive between the first surface and the substrate, achieving zero-residue imprinting.

[0050] In one embodiment, surface activation treatment of the first surface of the imprinted structure is performed by oxygen plasma along a first direction, including:

[0051] Oxygen plasma is injected into the first surface of the imprinted structure along the first direction using the ICP process.

[0052] One embodiment involves injecting oxygen plasma along a first direction onto the first surface of an imprinted structure using an ICP process, including:

[0053] The oxygen flow rate inside the ICP device is 8~10 sccm, and the oxygen pressure is 70~90 mT;

[0054] The power of the ICP device is 80~100W to ionize oxygen into oxygen plasma;

[0055] The ICP device has a power of 25~35W to apply oxygen plasma to the first surface, and the surface treatment time of the ICP device is 20~50s.

[0056] In one embodiment, the oxygen plasma includes oxygen atom free radicals, which undergo addition reactions with C=C double bonds and / or directly break the double bonds. After the addition reaction, intermediate products containing hydroxyl or peroxy bonds are generated, and the oxygen atom free radicals oxidize the intermediate products to aldehyde or carboxyl groups.

[0057] In one embodiment, the first surface of the imprinted structure reacts with an epoxy imprinting adhesive to remove the epoxy imprinting adhesive located between the first surface and the substrate, including:

[0058] Epoxy imprinting adhesives include epoxy groups, which react with carboxyl groups within at least a portion of the thickness of the imprinted structure via acid-catalyzed epoxy ring-opening to form a three-dimensional cross-linked network.

[0059] In one embodiment, the reaction time is set to 1.5 to 3 minutes.

[0060] In one embodiment, the thickness of the epoxy imprinting adhesive is 10 nm to 20 μm.

[0061] One embodiment of the preparation method further includes: providing a master template, the master template including a first micro-nano structure, and reprinting the master template to obtain a sub-template.

[0062] This invention requires no high temperature throughout the process, effectively avoiding the problem of acrylic acid's tendency to self-polymerize due to the presence of double bonds. The entire process is a spontaneous reaction, flexible and controllable, and suitable for micro and nano structures, especially those micro and nano structures that are too small to be treated with spot spraying technology (the structural region is much smaller than the area of ​​a drop of glue).

[0063] The present invention will be further described below with reference to specific embodiments.

[0064] Example 1:

[0065] Combination Figures 2a-2d As shown, a method for preparing micro / nano structures in one embodiment of the present invention includes:

[0066] S101, a sub-template 10 is provided, the sub-template 10 includes a base layer 11 and an embossing structure 12 protruding from the surface of the base layer, the embossing structure 12 having a first surface 101 away from the base layer 11.

[0067] The base layer 11 has a second surface 111 and a third surface 112 disposed opposite to each other (i.e., the base layer 11 is...). Figure 2a (The structure between the dashed line and the third surface 112 shown) The embossing structures 12 are spaced apart on the second surface 111, and the embossing structures 12 form recessed embossing cavities 13.

[0068] It is understood that the shape of the imprint cavity 13 is the shape of the target micro / nano structure, and the imprint structure 12 and the imprint cavity 13 can be fabricated according to the actual required structure. In this embodiment, the depth and duty cycle of the imprint cavity 13 are inconsistent (i.e., the thickness of the imprint structure 12 extending from the first surface 101 to the base layer 11 may be inconsistent, the cross-sectional dimensions of the imprint cavity 13 may be inconsistent, and multiple imprint cavities 13 may be arranged in a non-uniformly spaced manner). In other alternative embodiments, the imprint cavities 13 of the sub-template 10 may have the same depth and the same duty cycle, and be arranged in a uniformly spaced manner.

[0069] Sub-template 10 is made of acrylic material, which contains C=C double bonds and carboxyl functional groups (-COOH).

[0070] For example, the material of the sub-template 10 includes, but is not limited to, PMMA (polymethyl methacrylate), silicone fluorine-modified polyurethane acrylic resin, carboxylated acrylic resin, fluorine-modified acrylic ester, cationic hybrid acrylic resin and PET (polyethylene terephthalate). The overall thickness of the sub-template 10 can be selected according to actual needs, such as 0.5mm thickness.

[0071] It is understandable that acrylic acid is the simplest unsaturated aliphatic carboxylic acid. The carbon atom of the carboxylic acid in the molecule is sp² hybridized. The three hybrid orbitals form σ bonds with the carbonyl oxygen, hydroxy oxygen, and vinyl carbon. The p orbital on the carboxyl carbon overlaps with the p orbital on the carbonyl oxygen to form a π bond, which combines the chemical activity of double bonds and carboxyl groups.

[0072] S102, the first surface 101 of the imprinted structure 12 is surface activated by oxygen plasma along the first direction to drive the C=C double bond of the imprinted structure 12 with at least a partial thickness to be oxidized to carboxyl groups or the C=C double bond to be broken, the first direction x extending from the first surface 101 to the base layer 11.

[0073] Furthermore, in this embodiment, oxygen plasma is injected into the first surface 101 of the imprinted structure along a first direction using an ICP process. It is understood that ICP equipment is well-known in the prior art and therefore will not be described in detail here; any known or unknown ICP equipment may be used without limitation.

[0074] Specifically:

[0075] Fix the sub-template 10 on the sample stage of the ICP equipment, open the oxygen (O2) valve, set the oxygen flow rate to 10 sccm, and after the oxygen enters the chamber, adjust the chamber pressure (i.e. oxygen pressure) to 80 mT through the vacuum valve.

[0076] The power of the ICP device (ICP source power) is set to 100 W. Power is applied to the upper electrode through the radio frequency power supply to ionize oxygen molecules into oxygen plasma.

[0077] The power (bias power) of the ICP device is set to 30 W: an RF bias voltage is applied to the lower electrode (i.e., the sample stage) to generate an electric field that accelerates the oxygen plasma toward the first surface 11 to achieve surface activation.

[0078] Furthermore, in this embodiment, the surface activation process using an ICP device takes 20 seconds.

[0079] It should be noted that in this embodiment, only the first surface 101 is surface-treated, and the treatment direction is the first direction x shown in Figure 2, that is, the treatment direction is perpendicular to the first surface 101 and extends from the first surface 101 towards the base layer 11. Although only the first surface 101 is surface-treated, oxygen plasma will drive the C=C double bonds inside the imprinted structure 12 of a set thickness to oxidize to carboxyl groups or break the C=C double bonds from the first surface, combined with... Figure 3 As shown, the activation depth depends on the oxygen flow rate, oxygen pressure, ICP power, ICP power, and ICP processing time within the ICP device.

[0080] In this embodiment, the activation depth is equal to the depth of the imprinted structure 12. In other alternative embodiments, the activation depth is positively correlated with the residual adhesive thickness.

[0081] Combination Figure 2b As analyzed in the background art, when the impression cavity 13 has a non-uniform duty cycle or non-uniform height structure, the thicknesses of the first residual adhesive layer 2011, the second residual adhesive layer 2012, and the third residual adhesive layer 2013 are inconsistent. Experimental verification shows that the thickness of the residual adhesive layer on the side of the impression cavity 13 with a larger duty cycle is greater than that on the side of the impression cavity 13 with a smaller duty cycle. Therefore, in this embodiment, the activation treatment depth is set to be greater than or equal to the maximum thickness of the residual adhesive layer.

[0082] It should be noted that, in other alternative embodiments, the oxygen flow rate, oxygen pressure, ICP power, ICP power, and ICP processing time in the ICP device can be set to reasonable values ​​based on the actual needs of those skilled in the art or the thickness of the residual adhesive layer, thereby determining the activation treatment depth.

[0083] The functional groups of acrylic acid (C=C double bond, -COOH) react with oxygen plasma, and the reaction has typical plasma chemistry characteristics: chemical bond breaking and new bond formation are initiated by high-energy active species (rather than traditional thermal drive).

[0084] It is understandable that oxygen plasma is a mixed system generated by the ionization of oxygen in a high-energy field (such as radio frequency or microwave), and its core active components include: high-energy electrons (electrons). - ), oxygen radicals (O·, which have strong oxidizing properties), excited-state oxygen molecules (O2*), a small amount of ozone (O3), and oxygen ions (O2). + / O + )wait.

[0085] The bond energy of the C=C double bond is approximately 614 kJ / mol, while the CO bond energy in the carboxyl functional group (-COOH) is approximately 358 kJ / mol. The chemical bond energies of the oxygen plasma are much greater than those of the C=C double bond and the carboxyl functional group, which can directly break the molecular structure of acrylic acid and initiate subsequent reactions. The functional groups of acrylic acid (C=C double bond and -COOH) interact with the reactive species of the oxygen plasma. Oxygen radicals (O·) preferentially attack the C=C double bond with its high electron cloud density, resulting in addition reactions or direct cleavage of the double bond. The addition reaction produces intermediates containing hydroxyl groups (-OH) or peroxy bonds (-OO-), which are further oxidized by O· to ​​aldehyde groups (-CHO) or carboxyl groups (-COOH).

[0086] It is understandable that when the oxygen plasma has high energy, long activation time, or high oxygen concentration, some carboxyl functional groups will be oxidized and decomposed into CO2 and H2O.

[0087] S103, combined with Figure 2b As shown, an epoxy-based imprinting adhesive 20 of a predetermined thickness is coated on the surface of the substrate 30. In this embodiment, the substrate 30 is a silicon substrate. It should be noted that the material of the substrate 30 does not react with the sub-template 10 after treatment.

[0088] S104, the sub-template 10 is imprinted onto the epoxy imprinting adhesive 20. The first surface 101 of the imprinted structure reacts with the epoxy imprinting adhesive to remove the epoxy imprinting adhesive located between the first surface 101 and the substrate 30. It is understood that, based on the principle of anisotropy, the side surfaces of the imprinted structure 12 will not react with the epoxy imprinting adhesive.

[0089] Combination Figure 2b As shown, during the imprinting process, the first surface 101 of the imprinting structure is oriented toward the epoxy imprinting adhesive 20, and a certain pressure is applied to make the epoxy imprinting adhesive 20 fill the imprinting cavity 13.

[0090] S105, after setting the reaction time, the epoxy-based imprinting adhesive is cured and the sub-template is removed to obtain the micro / nano structure 202. The micro / nano structure 202 obtained after removing the sub-template is shown below. Figure 2d As shown.

[0091] Epoxy-based embossing adhesives refer to compounds whose molecular structure contains epoxy groups (three-membered epoxy rings, a three-membered ring structure composed of one oxygen atom and two adjacent carbon atoms). In this embodiment, the epoxy-based embossing adhesive is a bisphenol A type epoxy resin, whose molecular structure is formed by the condensation of bisphenol A (2,2-di-p-hydroxyphenylpropane) and epichlorohydrin under alkaline conditions. The molecule has epoxy groups at both ends, and the main chain contains benzene rings and ether bonds.

[0092] The carboxyl group is a weakly acidic functional group (pKa ≈ 2-5), which can directly react with the epoxy groups of bisphenol A type epoxy resin through "acid-catalyzed epoxy ring-opening" without demanding conditions. This is one of the core reactions in the "epoxy-carboxyl" crosslinking system in industry. The reaction process mainly includes:

[0093] Protonation activation of the epoxy ring: acidic hydrogen in the carboxyl group (H in -COOH) + It preferentially combines with the oxygen atoms of the epoxy group in bisphenol A type epoxy resin, thereby enhancing the positive charge of the epoxy ring and further increasing the strain of the three-membered ring (the original strain is ≈114kJ / mol, and it is more easily broken after protonation).

[0094] Nucleophilic attack ring opening: The carboxyl group dissociates into a carboxyl group (-COO). - Nucleophiles attack carbon atoms with lower electron cloud density on the epoxy ring (the epoxy ring of bisphenol A type epoxy has a symmetrical structure and the two carbon atoms have similar activity), causing the epoxy ring to break.

[0095] Bonding product: One end of the broken epoxy ring bonds with -COO - They combine to form an ester group (-COO-), with H attached to the other end. + A hydroxyl group (-OH) is formed.

[0096] If the carboxyl group comes from a small molecule carboxylic acid (such as adipic acid) or a carboxyl-modified polymer (such as carboxyl acrylic resin), the reaction can be further extended: the generated hydroxyl groups (-OH) can continue to react with unreacted epoxy groups, eventually forming a three-dimensional cross-linked network, in which the linear backbone of bisphenol A type epoxy is connected by ester bonds and ether bonds, and solidifies into a film.

[0097] Understandably, the reaction depth between the epoxy imprinting adhesive and the imprinted structure 12 depends on the thickness of the activated imprinted structure. (Combined) Figure 3 As shown, after surface activation treatment of the first surface 101 of the imprinted structure 12 in step S102, the C=C double bonds of the imprinted structure 12 with a thickness of h1 (h1 is also the activation treatment depth) are oxidized to carboxyl groups or broken. Therefore, in step S104, at most only the imprinted structure 12 with a thickness of h1 may react with the epoxy imprinting adhesive. In another alternative embodiment, after surface activation treatment, the C=C double bonds of the imprinted structure 12 with a thickness of h2 are oxidized to carboxyl groups or broken. Therefore, in step S104, at most only the imprinted structure 12 with a thickness of h2 may react with the epoxy imprinting adhesive.

[0098] Combination Figure 2c As shown, in this embodiment, the reaction time before curing is set to 2 minutes to ensure that the epoxy imprinting adhesive between the first surface 102 and the substrate 30 can fully react with the imprinting structure 12, ensuring that the imprinting structure 12 completely "absorbs" the residual adhesive. After the reaction is completed, it is cured under ultraviolet light, and a micro-nano structure without residual adhesive can be obtained after demolding.

[0099] Understandably, the macroscopic structure of the sub-template 10 does not change after demolding, but it does not have the function of "absorbing" residual adhesive again, and can be reused as a regular sub-template.

[0100] Furthermore, the preparation method of this embodiment also includes: providing a master template, the master template including a first micro-nano structure, the first micro-nano structure corresponding to the imprinted structure image of the sub-template, and reprinting the master template to obtain the sub-template.

[0101] A micro / nano structure was prepared using this method, eliminating the need for additional steps to remove residual adhesive.

[0102] It will be apparent to those skilled in the art that this disclosure is not limited to the details of the exemplary embodiments described above, and that this disclosure can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of this disclosure is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this disclosure. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0103] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing micro / nano structures, characterized in that, The preparation method includes: A sub-template is provided, the sub-template being made of an acrylic material having C=C double bonds and carboxyl functional groups. The sub-template includes a base layer and an embossed structure protruding from the surface of the base layer, the embossed structure having a first surface away from the base layer. Based on the ICP process, oxygen is ionized into oxygen plasma, and oxygen plasma is injected into the first surface of the imprinted structure along the first direction. The first surface of the imprinted structure is activated by the oxygen plasma to drive the oxidation of C=C double bonds of at least a portion of the thickness of the imprinted structure to carboxyl groups or the breakage of C=C double bonds. The first direction extends from the first surface to the base layer. An epoxy-based imprinting adhesive of a predetermined thickness is coated onto the substrate surface; The sub-template is imprinted onto the epoxy imprinting adhesive, and the first surface of the imprinted structure reacts with the epoxy imprinting adhesive to remove the epoxy imprinting adhesive located between the first surface and the substrate; After setting the reaction time, the epoxy-based imprinting adhesive is cured and the sub-template is removed to obtain a micro / nano structure without adhesive residue.

2. The method for preparing micro / nano structures according to claim 1, characterized in that, Injecting oxygen plasma along a first direction into the first surface of the imprinted structure using an ICP process includes: The oxygen flow rate inside the ICP device is 8~10 sccm, and the oxygen pressure is 70~90 mT; The power of the ICP device is 80~100W to ionize the oxygen into oxygen plasma; The ICP device has a power of 25~35W to apply the oxygen plasma to the first surface, and the surface treatment time of the ICP device is 20~50s.

3. The method for preparing micro / nano structures according to claim 1, characterized in that, The oxygen plasma includes oxygen free radicals, which undergo addition reactions with C=C double bonds and / or directly break the double bonds. After the addition reaction, intermediate products containing hydroxyl or peroxy bonds are generated. The oxygen free radicals oxidize the intermediate products to aldehyde or carboxyl groups.

4. The method for preparing micro / nano structures according to claim 1, characterized in that, The first surface of the imprinted structure reacts with the epoxy imprinting adhesive to remove the epoxy imprinting adhesive located between the first surface and the substrate, including: The epoxy imprinting adhesive includes epoxy groups, and the epoxy groups and carboxyl groups within at least a portion of the thickness of the imprinting structure react with the epoxy groups through acid-catalyzed ring-opening to form a three-dimensional cross-linked network.

5. The method for preparing micro / nano structures according to claim 1, characterized in that, The set reaction time is 1.5 to 3 minutes.

6. The method for preparing micro / nano structures according to claim 1, characterized in that, The thickness of the epoxy-based imprinting adhesive is 10 nm to 20 μm.

7. The method for preparing micro / nano structures according to claim 1, characterized in that, The preparation method further includes: providing a master template, the master template including a first micro-nano structure, and reprinting the master template to obtain the sub-template.

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