Micro-nano structure, preparation method and application thereof

Abstract

The present invention discloses a micro-nano structure, a preparation method and application thereof, the preparation method comprising: preparing a hard template and a soft template, wherein the hard template is provided with micron-level through holes along the thickness direction, and the soft template is provided with nano-level microstructures; taking a substrate, coating a stamping glue on the surface of the substrate; attaching the hard template to the surface of the substrate, the stamping glue is filled in the through holes of the hard template, and the stamping glue overflows the through holes to form a protrusion at the through hole mouth; attaching the side of the soft template provided with a nano-level microstructure to the side of the hard template away from the substrate, applying pressure to the soft template, and the stamping glue protrusion overflowing from the through holes on the hard template is filled in the nano-level microstructure of the soft template; curing the stamping glue; removing the soft template and the hard template to obtain the micro-nano structure. The present invention selects a hard template with a hollow micron structure and a soft template with a nano-level microstructure, and can obtain the required micron and nano-composite binary microstructure simply and quickly through one stamping exposure and two demolding processes.

Description

Technical Field

[0001] The present invention belongs to the technical field of micro-nano structure preparation, and particularly relates to a micro-nano structure, a preparation method thereof, and an application thereof. Background Art

[0002] Traditionally, to fabricate a nanostructure on a microscale structure, methods such as imprinting or etching can be used. If the imprinting method is adopted, it is a huge challenge for the template fabrication process, which requires the structure to cover both the microscale and nanoscale, and the period of the two structural dimensions differs by more than a hundred times or even reaches several thousand times. Only by fabricating a precisely and completely structured template can the microscale and nanostructures be imprinted at one time.

[0003] If the photolithography etching method is used, first, the structure needs to be exposed and etched twice. Compared with the imprinting process, the steps are relatively more. Moreover, for microstructures with nanoscale dimensions, compared with nanoimprinting technology, due to the light diffraction and scattering effects of the etching light source, the nanostructures cannot accurately meet the design requirements.

[0004] The information disclosed in this background art section is only intended to enhance the overall understanding of the present invention and should not be regarded as an admission or any form of implication that this information constitutes prior art already known to those of ordinary skill in the art. Summary of the Invention

[0005] The purpose of the present invention is to provide a micro-nano structure, a preparation method thereof, and an application thereof, which can simply and quickly form a nanostructure on a microscale structure.

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

[0007] A preparation method of a micro-nano structure, comprising the following steps:

[0008] Prepare a hard template and a soft template, wherein the hard template is provided with micron-level through holes along the thickness direction, and the soft template is provided with nano-level microstructures;

[0009] Take a substrate and coat an imprinting adhesive on the surface of the substrate;

[0010] Attach the hard template to the surface of the substrate, and the hard template squeezes the imprinting adhesive so that the imprinting adhesive fills the through holes of the hard template, and the imprinting adhesive overflows from the through holes to form a protruding part at the orifice of the through holes;

[0011] Attach the side of the soft template with nano-level microstructures to the side of the hard template facing away from the substrate, apply pressure to the soft template, and the protruding part of the imprinting adhesive overflowing from the through holes of the hard template fills the nano-level microstructures of the soft template;

[0012] Cure the imprinting adhesive;

[0013] Remove the soft template and the hard template to obtain the micro-nano structure.

[0014] In one or more embodiments of the present invention, the aspect ratio of the through holes in the hard template is (5-20):1.

[0015] In one or more embodiments of the present invention, the thickness of the hard template is 50-500 μm.

[0016] In one or more embodiments of the present invention, the coating thickness of the imprinting glue on the substrate surface is 10-200 μm.

[0017] In one or more embodiments of the present invention, the viscosity of the imprinting glue is 10-150 cP.

[0018] In one or more embodiments of the present invention, after the hard template is attached to the substrate surface, a pressure less than or equal to 1 bar is applied to the hard template.

[0019] In one or more embodiments of the present invention, after the soft template is attached to the hard template, a pressure of 1-20 bar is applied to the soft template.

[0020] In one or more embodiments of the present invention, the specific operation of removing the soft template and the hard template is as follows: first fix the substrate, remove the soft template, then fix the hard template, and remove the hard template together with the substrate and the micro-nano structure on the substrate.

[0021] The technical solution provided by another specific embodiment of the present invention is as follows:

[0022] A micro-nano structure is prepared by the preparation method of the above micro-nano structure.

[0023] The technical solution provided by a specific embodiment of the present invention is as follows:

[0024] The application of the above micro-nano structure in new energy devices, biomedical detection devices, microfluidic devices, electronic devices, optical components or nanoimprinting.

[0025] Compared with the prior art, the present invention first prepares a hard template with micron-level through holes and a soft template with nano-level microstructures on the surface. By coating an imprinting glue on the substrate, and then through one-time imprinting exposure and two-time demolding, the required micro-nano structure is formed. The overall preparation process is simple, and the nano structure can be conveniently and quickly formed on the micron structure to obtain the target micro-nano structure. Description of the Drawings

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0027] Figure 1 Schematic diagram of a hard template in an embodiment of the present invention;

[0028] Figure 2 Schematic diagram of a soft template in an embodiment of the present invention;

[0029] Figure 3 Schematic diagram of a substrate coated with photoresist placed on a glass substrate in an embodiment of the present invention;

[0030] Figure 4 Schematic diagram of a hard template placed on photoresist in an embodiment of the present invention;

[0031] Figure 5 Schematic diagram of applying pressure to a hard template in an embodiment of the present invention;

[0032] Figure 6 Schematic diagram of photoresist filling the through holes of the hard template and forming a protruding part in an embodiment of the present invention;

[0033] Figure 7 Schematic diagram of the protruding part filling the microstructures of the soft template in an embodiment of the present invention;

[0034] Figure 8 Schematic diagram of curing photoresist in an embodiment of the present invention;

[0035] Figure 9 Schematic diagram of removing the soft template in an embodiment of the present invention;

[0036] Figure 10 Schematic diagram of removing the hard template in an embodiment of the present invention;

[0037] Figure 11 Schematic diagram of the substrate and the micro-nano structures on the substrate surface in an embodiment of the present invention. Detailed implementation manners

[0038] To enable those skilled in the art to better understand the technical solutions in the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0039] A specific embodiment of the present invention provides a preparation method for micro-nano structures, including steps 1-6.

[0040] Step 1: Prepare a hard template and a soft template. The hard template is provided with micron-level through holes in the thickness direction, and the soft template is provided with nano-level microstructures.

[0041] Specifically, the hard template is selected as a single-crystalline silicon wafer with a thickness between dozens of microns and hundreds of microns, such as 50-500 μm. The specific thickness can be selected according to actual needs. For example, a single-crystalline silicon wafer with a thickness of 300 μm is selected, and through holes are made by conventional etching or laser drilling processes, and then the thickness of the hard template is thinned to 200 μm by grinding and polishing processes. The aspect ratio of the through holes is (5-20):1.

[0042] The material of the soft template includes but is not limited to PC (polycarbonate), PMMA (polymethyl methacrylate), and PET (polyethylene terephthalate). The thickness of the soft template can be selected according to actual needs, such as selecting a thickness of 0.5 mm. The nano-level microstructures on the soft template are prepared according to the actually required structures. For example, a photoresist is spin-coated on the soft template by a spin-coating process, and then the photoresist is imprinted with a silicon material template with nano-structures, and the photoresist is cured by ultraviolet exposure, so that the microstructures on the silicon material template are transferred to the soft template.

[0043] In addition, in order to facilitate subsequent demolding, anti-adhesion treatments are performed on the nano-microstructures on the hard template and the soft template. The anti-adhesion treatment can select the principle of reactive ion etching for surface deposition of an anti-adhesion layer. For example, C4F8 anti-adhesion treatment is performed on the nano-microstructures on the hard template and the soft template.

[0044] Step 2: Take a substrate and coat an imprinting adhesive on the surface of the substrate.

[0045] Specifically, the viscosity of the imprinting adhesive is 10-150 cP, and the coating thickness is 10-200 μm, which can ensure that the subsequent imprinting adhesive can fill the through holes of the hard template. The substrate is a transparent plastic film, and the specific material can be selected as PC, PMMA, or PET. The imprinting adhesive can be selected as a conventional photoresist and cured by ultraviolet light irradiation later, or a conventional thermosetting imprinting adhesive can be selected and cured by heating later. When selecting a photoresist, both the soft template and the substrate are transparent to facilitate ultraviolet light irradiation of the photoresist.

[0046] Step 3: Attach the hard template to the surface of the substrate. The hard template presses the imprinting glue so that the imprinting glue fills the through holes of the hard template, and the imprinting glue overflows from the through holes to form a protrusion at the orifice of the through holes.

[0047] Specifically, after the hard template is placed on the surface of the substrate, the natural gravity of the hard template will press the imprinting glue, causing the imprinting glue to be injected into the through holes of the hard template. According to the actual situation, a pressure less than or equal to 1 bar can be applied to the hard template manually or by using a mechanical device, so that the imprinting glue is injected into the through holes and overflows from the through holes, forming a protrusion at the orifice of the through holes. This protrusion is used to fill the nano-scale microstructures of the soft template subsequently. In addition, by controlling the viscosity of the imprinting glue, it is helpful for the imprinting glue to fill the through holes of the hard template and form a protrusion. Moreover, when the imprinting glue fills the through holes, it can extrude the air in the through holes to prevent the formation of bubbles.

[0048] Step 4: Attach the side of the soft template with nano-scale microstructures to the side of the hard template facing away from the substrate, and apply pressure to the soft template. The protrusion of the imprinting glue overflowing from the through holes of the hard template fills the nano-scale microstructures of the soft template.

[0049] Specifically, apply a pressure of 1 - 20 bar to the soft template to fill the protrusion at the orifice of the through holes into the microstructures of the soft template. This step can be carried out in an imprinting machine. By using air pressure, the pressure is fully released to the entire surface of the soft template, and the soft template, the imprinting glue, the imprinting glue in the hard template, the hard template, and the substrate are imprinted from top to bottom, which can effectively ensure the formation of the required micro-nano structures.

[0050] Step 5: Cure the imprinting glue.

[0051] Specifically, select the corresponding curing method according to the type of the imprinting glue. For example, if a photoresist is selected, since the hard template is a single-crystalline silicon wafer and is opaque, ultraviolet exposure can be carried out simultaneously from top and bottom to cure the imprinting glue.

[0052] Step 6: Remove the soft template and the hard template to obtain the micro-nano structure.

[0053] Specifically, use a suction cup to fix the substrate by vacuum adsorption first, then remove the soft template to separate the soft template from the imprinting glue located at the top layer. Then fix the hard template by vacuum adsorption and separate the substrate from the hard template. During the separation process, the micro-nano structure on the surface of the substrate is separated from the substrate together with the hard template. Moreover, the residual glue of the nano-imprinting glue on the top layer located on the hard template will burst open at the moment of demolding and separate from the micro-nano structure, thus obtaining a complete micro-nano structure.

[0054] Another specific embodiment of the present invention provides a micro-nano structure prepared by the above preparation method of the micro-nano structure.

[0055] Another specific embodiment of the present invention provides the application of the above micro-nano structure in new energy devices, biomedical detection devices, microfluidic devices, electronic devices, optical components or nanoimprinting.

[0056] Specifically, the prepared micro-nano structure can be used as a template to make a sub-template again, or a production template, for large-scale imprinting. In addition, in the production of anti-counterfeiting graphics, the preparation method of the micro-nano structure in the present invention can be selected to produce anti-counterfeiting graphics, or the micro-nano structure can be used as a template for anti-counterfeiting graphic imprinting.

[0057] The present invention will be further described in detail below with reference to specific embodiments.

[0058] Example 1

[0059] The preparation method of the micro-nano structure includes the following steps:

[0060] Select a single-crystalline silicon wafer with a thickness of 300 μm, and use an etching method to make through-holes with an aspect ratio of 10:1 along its thickness direction. Then, through grinding and polishing, the thickness is thinned to 200 μm, and then C4F8 anti-adhesion treatment is carried out to obtain a hard template as shown in Figure 1 .

[0061] Select a transparent PC board with a thickness of 0.5 mm, spin-coat a photoresist on the surface of the PC board, then attach a silicon material template with nano-scale microstructures to the photoresist for imprinting, and then cure the photoresist by ultraviolet exposure to form nano-scale microstructures on the surface of the PC board. Then, C4F8 anti-adhesion treatment is carried out to obtain a soft template as shown in Figure 2 .

[0062] Refer to Figure 3 , Figure 4 and Figure 5 , take a substrate made of transparent PC, coat a photoresist with a thickness of 30 μm on the substrate, the viscosity of the photoresist is 15 cP, place the substrate on a transparent glass base, with the side coated with the photoresist facing up. Place the hard template on the photoresist, apply a pressure of 1 bar to the hard template to inject the photoresist into the through-holes, and the photoresist exposes the through-holes and retains a part at the orifice of the through-holes to form a protrusion as shown in Figure 6 .

[0063] Refer to Figure 7 , place the side of the soft template with microstructures on the hard template, in an imprinting machine, apply a pressure of 10 bar to the soft template by means of air pressure to fill the protrusion into the microstructures of the soft template.

[0064] Refer to Figure 8 , and cure the photoresist by means of simultaneous ultraviolet exposure from above and below.

[0065] Reference Figure 9 , the substrate is fixed by vacuum adsorption to separate the soft template from the top-layer photoresist, realizing the first demolding.

[0066] Reference Figure 10 , the hard template is fixed by vacuum adsorption to separate the substrate and the micro-nano structures on the substrate surface from the hard template together, realizing the second demolding. During this process, the residual photoresist on the surface of the hard template will burst open at the moment of demolding and separate from the micro-nano structures, obtaining the micro-nano structures existing on the substrate as shown in Figure 11 .

[0067] In summary, the present invention uses a hollow hard template and a soft template with nano-micro structures, and through one-time imprinting exposure and two demoldings, a binary micro-structure composed of a micron structure and a nano structure is obtained. It is not only simple and fast to operate, but also can obtain a binary micro-structure with precise structure.

[0068] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claims involved.

[0069] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard 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 a micro-nano structure, characterized in that: The steps include: A hard template and a soft template are prepared, wherein the hard template is provided with micrometer-level through holes along the thickness direction, and the soft template is provided with a nanometer-level microstructure; Take the substrate and apply the embossing glue on the surface of the substrate; The hard template is attached to the surface of the substrate, and the hard template squeezes the embossing glue so that the embossing glue fills the through hole of the hard template, and the embossing glue overflows the through hole to form a protrusion at the through hole opening; The side of the soft template provided with the nano-scale microstructure is attached to the side of the hard template facing away from the substrate, and the soft template is pressed so that the protruding part of the embossing glue overflowing from the through hole of the hard template is filled in the nano-scale microstructure of the soft template; Curing the embossing adhesive; Remove the soft template and hard template to obtain micro-nanostructure; The specific operation of removing the soft template and the hard template is: first fix the substrate, remove the soft template, and then fix the hard template, and remove the substrate and the micro-nano structure on the substrate together.

2. The method for preparing a micro-nano structure according to claim 1, characterized in that: The aspect ratio of the through hole in the hard template is (5-20):

1.

3. The method for preparing a micro-nano structure according to claim 1, characterized in that: The hard template has a thickness of 50 to 500 μm.

4. The method for preparing a micro-nano structure according to claim 1, characterized in that: The coating thickness of the embossing glue on the substrate surface is 10-200 μm.

5. The method for preparing a micro-nano structure according to claim 1, characterized in that: The viscosity of the embossing glue is 10-150 cP.

6. The method for preparing a micro-nano structure according to claim 1, characterized in that: After the hard template is attached to the surface of the substrate, a pressure less than or equal to 1 bar is applied to the hard template.

7. The method for preparing a micro-nano structure according to claim 1, characterized in that: After the soft template is attached to the hard template, a pressure of 1 to 20 bar is applied to the soft template.

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