Micro-nano structure as well as preparation method and application thereof

Abstract

The invention discloses a micro-nano structure and a preparation method and application thereof, the preparation method comprises the following steps: preparing a hard template and a soft template, the hard template is provided with micron-scale through holes along the thickness direction, and the soft template is provided with a nano-scale microstructure; taking a substrate, and coating imprinting glue on the surface of the substrate; the hard template is attached to the surface of the substrate, the through hole of the hard template is filled with the imprinting glue, and the imprinting glue overflows out of the through hole to form a protruding part at the hole opening of the through hole; the face, provided with the nanoscale microstructure, of the soft template is attached to the face, away from the substrate, of the hard template, pressure is applied to the soft template, and the nanoscale microstructure of the soft template is filled with the imprinting glue protruding parts, overflowing out of the through holes, of the hard template; curing the imprinting glue; and removing the soft template and the hard template to obtain the micro-nano structure. According to the method, the hard template with the hollow micron structure and the soft template with the nano microstructure are selected, and the required micron and nano composite binary microstructure can be simply and quickly obtained through one-time imprinting exposure and two-time demolding processes.

Description

Technical Field

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

[0002] Traditionally, nanostructures can be made on microstructures by embossing or etching. If the embossing method is used, it is a huge challenge for the template making process. The structure needs to cover both the microscale and the nanoscale, and the size period of the two structures needs to differ by more than a hundred times or even thousands of times. Only by making a template with a precise and complete structure can the microstructure and nanostructure be embossed at one time.

[0003] If the photolithography method is used, the structure needs to be exposed and etched twice, which is relatively more steps than the imprint process. In addition, for nano-sized microstructures, compared with the nanoimprint process, the etching light source has a light diffraction and scattering effect, resulting in the nanostructure not being able to accurately meet the design requirements.

[0004] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0005] The object 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 microstructure.

[0006] In order to achieve the above object, a technical solution provided by a specific embodiment of the present invention is as follows: A method for preparing a micro-nano structure comprises the following steps: 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.

[0007] In one or more embodiments of the present invention, the aspect ratio of the through hole in the hard template is (5-20):1.

[0008] In one or more embodiments of the present invention, the hard template has a thickness of 50-500 μm.

[0009] In one or more embodiments of the present invention, the coating thickness of the embossing glue on the surface of the substrate is 10-200 μm.

[0010] In one or more embodiments of the present invention, the viscosity of the embossing glue is 10-150 cP.

[0011] In one or more embodiments of the present invention, 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.

[0012] In one or more embodiments of the present invention, after the soft template is attached to the hard template, a pressure of 1 to 20 bar is applied to the soft template.

[0013] In one or more embodiments of the present invention, 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.

[0014] Another specific embodiment of the present invention provides a technical solution as follows: A micro-nano structure is prepared by the above-mentioned micro-nano structure preparation method.

[0015] The technical solution provided by a specific embodiment of the present invention is as follows: The above-mentioned micro-nano structures are used in new energy devices, biomedical detection devices, microfluidic devices, electronic devices, optical components or nanoimprinting.

[0016] Compared with the prior art, the present invention first prepares a hard template with micron-scale through holes and a soft template with nano-scale microstructures on the surface, and then forms the required micro-nano structure by coating an imprint glue on the substrate, and then performing one imprint exposure and two demolding. The overall preparation process is simple, and the nanostructure can be formed on the microstructure conveniently and quickly to obtain the target micro-nano structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 is a schematic diagram of a hard template in one embodiment of the present invention; Figure 2is a schematic diagram of a soft template in one embodiment of the present invention; Figure 3 It is a schematic diagram of placing a substrate coated with photoresist on a glass base in one embodiment of the present invention; Figure 4 A schematic diagram of placing a hard template on a photoresist in one embodiment of the present invention; Figure 5 A schematic diagram of applying pressure to a hard template in one embodiment of the present invention; Figure 6 A schematic diagram of a photoresist filling a through hole of a hard template and forming a protrusion in one embodiment of the present invention; Figure 7 A schematic diagram of a soft template microstructure filled with protrusions in one embodiment of the present invention; Figure 8 is a schematic diagram of curing photoresist in one embodiment of the present invention; Fig. 9 A schematic diagram of removing a soft template in one embodiment of the present invention; Fig.10 A schematic diagram of removing a hard template according to an embodiment of the present invention; Fig.11 FIG. 1 is a schematic diagram of a substrate and micro-nano structures on the substrate surface in one embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0020] A specific embodiment of the present invention provides a method for preparing a micro-nano structure, comprising steps 1-6.

[0021] Step 1, prepare a hard template and a soft template, the hard template is provided with micron-scale through holes along the thickness direction, and the soft template is provided with nano-scale microstructures.

[0022] Specifically, the hard template uses a single crystal silicon wafer with a thickness ranging from tens of microns to hundreds of microns, such as 50 to 500 μm. The specific thickness can be selected according to actual needs. For example, a single crystal silicon wafer with a thickness of 300 μm is selected, and a through hole is made by conventional etching or laser drilling process, and then the hard template thickness is thinned to 200 μm through a grinding and polishing process. The aspect ratio of the through hole is (5 to 20):1.

[0023] The soft template material 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 0.5mm. The nanoscale microstructure on the soft template is prepared according to the actual required structure, such as using a spin coating process to spin-coat the photoresist on the soft template, and then using a silicon material template with a nanostructure to imprint the photoresist, and curing the photoresist by ultraviolet exposure, so that the microstructure on the silicon material template is transferred to the soft template.

[0024] In addition, in order to facilitate subsequent demolding, the nano-microstructures on the hard template and the soft template are treated with anti-adhesion. The anti-adhesion treatment can use the reactive ion etching principle to deposit an anti-adhesion layer on the surface, such as C4F8 anti-adhesion treatment on the nano-microstructures on the hard template and the soft template.

[0025] Step 2: Take the substrate and apply embossing glue on the surface of the substrate.

[0026] Specifically, the viscosity of the imprint glue is 10-150cP, and the coating thickness is 10-200μm, which can ensure that the subsequent imprint glue can fill the hard template through-holes. The substrate is a transparent plastic film, and the specific material can be PC, PMMA or PET. The imprint glue can use conventional photoresist, which is subsequently cured by ultraviolet light irradiation, or conventional thermosetting imprint glue, which is subsequently cured by heating. When selecting photoresist, both the soft template and the substrate are transparent, which is convenient for ultraviolet light to irradiate the photoresist.

[0027] Step 3, attaching the hard template to the surface of the substrate, the hard template squeezes the embossing glue so that the embossing glue fills the through holes of the hard template, and the embossing glue overflows the through holes to form protrusions at the through hole openings.

[0028] Specifically, after the hard template is placed on the substrate surface, the natural gravity of the hard template will squeeze the embossing glue, so that the embossing glue is injected into the through-holes of the hard template. According to the actual situation, the hard template can be manually or mechanically applied with a pressure of less than or equal to 1 bar, so that the embossing glue is injected into the through-holes and overflows from the through-holes, forming a protrusion at the through-hole mouth, which is used to subsequently fill the nano-scale microstructure of the soft template. In addition, by controlling the viscosity of the embossing glue, it is helpful to make the embossing glue fill the through-holes of the hard template and form a protrusion. Moreover, when filling the through-holes, the embossing glue can squeeze out the air in the through-holes to prevent the formation of bubbles.

[0029] Step 4: attach the side of the soft template with the nanoscale microstructure to the side of the hard template facing away from the substrate, apply pressure to the soft template, and fill the nanoscale microstructure of the soft template with the embossing glue protruding from the through hole of the hard template.

[0030] Specifically, a pressure of 1 to 20 bar is applied to the soft template so that the protrusion at the through hole opening is filled into the microstructure of the soft template. This step can be performed in an imprinting machine, and the air pressure is used to fully release the pressure to the entire surface of the soft template, and the soft template, imprinting glue, imprinting glue in the hard template, hard template and substrate are imprinted from top to bottom, which can effectively ensure the formation of the desired micro-nano structure.

[0031] Step 5: Curing the embossing adhesive.

[0032] Specifically, a corresponding curing method is selected according to the type of imprint adhesive. For example, if photoresist is selected, since the hard template is a single crystal silicon wafer, which is opaque, ultraviolet exposure can be performed simultaneously from top to bottom to cure the imprint adhesive.

[0033] Step 6, remove the soft template and the hard template to obtain the micro-nano structure.

[0034] Specifically, the substrate is first fixed by vacuum adsorption using a suction cup, and then the soft template is removed to separate the soft template from the embossing glue on the top layer. The hard template is then fixed by vacuum adsorption to 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 hard template together with the substrate. Moreover, the residual nano-embossing glue on the top layer on the hard template will collapse and separate from the micro-nano structure at the moment of demolding, thereby obtaining a complete micro-nano structure.

[0035] Another specific embodiment of the present invention provides a micro-nano structure, which is prepared by the above-mentioned micro-nano structure preparation method.

[0036] Another specific embodiment of the present invention provides the application of the above-mentioned micro-nano structure in new energy devices, biomedical detection devices, microfluidic devices, electronic devices, optical components or nanoimprinting.

[0037] Specifically, the prepared micro-nano structure can be used as a template to make a sub-template again, or to make a production template for large-scale imprinting. In addition, in the production of anti-counterfeiting patterns, the micro-nano structure preparation method of the present invention can be used to make anti-counterfeiting patterns, or the micro-nano structure can be used as a template for imprinting anti-counterfeiting patterns.

[0038] The present invention is further described in detail below in conjunction with specific embodiments.

[0039] Example 1

[0040] The method for preparing a micro-nano structure comprises the following steps: A 300 μm thick single crystal silicon wafer was selected, and a through hole with a depth-to-width ratio of 10:1 was made along its thickness direction by etching. Then, the thickness was reduced to 200 μm by grinding and polishing, and then C4F8 anti-adhesion treatment was performed to obtain the following: Figure 1 Hard template shown.

[0041] A transparent PC board with a thickness of 0.5 mm was selected, and photoresist was spin-coated on the surface of the PC board. Then, a silicon material template with a nano-scale microstructure was attached to the photoresist for imprinting. The photoresist was cured by ultraviolet exposure to form a nano-scale microstructure on the surface of the PC board. Then, C4F8 anti-adhesion treatment was performed to obtain the following Figure 2 Soft template shown.

[0042] Reference Figure 3 , Figure 4 and Figure 5 , take a substrate made of transparent PC, coat a 30μm thick photoresist on the substrate, the viscosity of the photoresist is 15cP, place the substrate on a transparent glass base, with the side with the photoresist facing up. Place a hard template on the photoresist, apply 1 bar pressure to the hard template, inject the photoresist into the through hole, expose the through hole and retain part of the photoresist at the through hole mouth to form a Figure 6 The protrusion shown.

[0043] Reference Figure 7 , the side of the soft template with the microstructure is placed on the hard template, and in the embossing machine, a pressure of 10 bar is applied to the soft template by air pressure so that the protrusions are filled into the microstructure of the soft template.

[0044] Reference Figure 8 The photoresist is cured by simultaneous ultraviolet exposure from top to bottom.

[0045] Reference Fig. 9 The substrate is fixed by vacuum adsorption, so that the soft template is separated from the top layer of photoresist to achieve the first demolding.

[0046] Reference Fig.10 The hard template is fixed by vacuum adsorption, so that the substrate and the micro-nano structure on the substrate surface are separated from the hard template together, and the second demolding is achieved. In this process, the photoresist residue on the surface of the hard template will break apart and separate from the micro-nano structure at the moment of demolding, and the following is obtained: Fig.11 The micro-nanostructures shown exist on the substrate.

[0047] In summary, the present invention uses a hollow hard template and a soft template with a nanostructure to obtain a binary microstructure of a microstructure and a nanostructure through one imprint exposure and two demolding steps. This is not only simple and quick to operate, but also can obtain a binary microstructure with a precise structure.

[0048] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0049] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes 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.

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.

8. The method for preparing a micro-nano structure according to claim 1, characterized in that: 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.

9. A micro-nano structure, characterized in that: The micro-nano structure is prepared by the preparation method of any one of claims 1 to 8.

10. Application of the micro-nano structure according to claim 9 in new energy devices, biomedical detection devices, microfluidic devices, electronic devices, optical components or nanoimprinting.

Images