Method for manufacturing carbon-based microstructure

Abstract

The present invention relates to a method for manufacturing a carbon-based microstructure and provides a method for manufacturing a carbon-based microstructure enabling precise bending or folding of a carbon-based thin film as well as graphene.

Description

Method for manufacturing carbon-based microstructures

[0001] The present invention relates to a method for manufacturing a carbon-based microstructure and a carbon-based microstructure manufactured therefrom. This invention claims the benefit of Korean Patent Application No. 10-2024-0053330, filed with the Korean Intellectual Property Office on April 22, 2024, the entire contents of which are incorporated herein by reference.

[0002] Origami is a technology that transforms two-dimensional planar materials by bending or folding them to form unique three-dimensional structures. These three-dimensional structures, created by bending or folding micrometer-scale materials, are actively utilized in various fields such as sensors, biotechnology, photonics, flexible electronics, and robotics. Among two-dimensional planar materials, graphene, in particular, possesses excellent mechanical, electrical, and chemical properties. Therefore, research on origami, which involves bending or folding graphene, has been increasing recently. However, existing techniques for folding graphene mostly utilize temperature differences, chemical reactions, or prestrain of the substrate itself. These techniques suffer from technical limitations, making it difficult to control the desired folding or bending of graphene.

[0003] Therefore, there is a growing need for origami technology that can precisely bend or fold carbon-based thin films, including graphene, at a level that is difficult to achieve with existing technologies.

[0004] The technical problem to be achieved by the present invention is to provide a method for manufacturing a carbon-based microstructure capable of precisely bending or folding a carbon-based thin film.

[0005] However, the problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned can be clearly understood by those skilled in the art from the description below.

[0006] One embodiment of the present invention provides a method for manufacturing a carbon-based microstructure, comprising: forming a carbon-based thin film layer on at least a portion of a substrate; coating polymethyl methacrylate (PMMA) on the substrate on which the carbon-based thin film layer is formed to form a PMMA thin film layer; patterning the PMMA thin film layer; etching the carbon-based thin film layer to form an intermediate structure including a portion where only the patterned PMMA thin film layer exists and a portion where the patterned PMMA thin film layer and the patterned carbon-based thin film layer are bonded; etching the substrate on which the intermediate structure is formed to form a support portion that supports the intermediate structure; and applying energy to at least a portion of the patterned PMMA thin film layer to bend the intermediate structure.

[0007] Another embodiment of the present invention provides a carbon-based microstructure manufactured by the method for manufacturing the carbon-based microstructure.

[0008] The method for manufacturing a carbon-based microstructure according to the present invention can manufacture various and sophisticated three-dimensional carbon-based microstructures by controlling the bending and folding of a carbon-based thin film layer.

[0009] The effects of the present invention are not limited to the effects described above, and effects not mentioned will be clearly understood by those skilled in the art from the present specification and the attached drawings.

[0010] Figure 1 is a flowchart of a method for manufacturing a carbon-based microstructure according to one embodiment of the present invention.

[0011] Figure 2 is a drawing schematically showing each step of a method for manufacturing a carbon-based microstructure according to one embodiment of the present invention.

[0012] Figure 3 is a SEM image showing the intermediate structure with a butterfly-shaped pattern formed thereon being bent when an electron beam is irradiated on the intermediate structure at an accelerating voltage of 2 kV.

[0013] Figure 4 is a SEM image showing bending induced only in a specific part of the intermediate structure by irradiating an electron beam on a specific part of the patterned PMMA thin film layer of the intermediate structure.

[0014] Figure 5 is an SEM image showing the appearance of the intermediate structure being bent when irradiated with an electron beam at an acceleration voltage of 2 kV and 5 kV for a portion (a) where only the patterned PMMA thin film layer of the intermediate structure exists and a portion (b) where the patterned PMMA thin film layer and the patterned carbon thin film layer are bonded.

[0015] Figures 6a, 6b and 6c are schematic diagrams and SEM images showing the simultaneous implementation of bidirectional bending within a single structure by irradiating an electron beam with an acceleration voltage of 5 kV on an intermediate structure including a portion where only a PMMA thin film layer exists and a portion where a patterned PMMA thin film layer and a patterned carbon thin film layer are bonded.

[0016] Figure 7a is a schematic diagram showing the formation of a carbon microstructure in a cubic structure by irradiating an electron beam to a corner portion included in an intermediate structure in which a pattern in the shape of a cubic development diagram has been formed.

[0017] Figure 7b is an optical microscope image of an intermediate structure formed in the shape of a cubic development diagram using the method of Example 1.

[0018] Figure 7c is a SEM image showing the formation of a carbon-based microstructure in a cubic shape by irradiating an electron beam at an acceleration voltage of 2 kV on the corner of an intermediate structure that has formed a pattern in the shape of a cubic development diagram.

[0019] Throughout this specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0020] Throughout this specification, when it is said that an element is "on" another element, this includes not only cases where the element is in contact with the other element, but also cases where another element exists between the two elements.

[0021] Throughout this specification, the unit “parts by weight” may mean the weight ratio between each component.

[0022] Throughout this specification, “A and / or B” means “A and B, or A or B.”

[0023] Figure 1 is a flowchart of a method for manufacturing a carbon-based microstructure according to one embodiment of the present invention.

[0024] One embodiment of the present invention provides a method for manufacturing a carbon-based microstructure, comprising: a step (S1) of forming a carbon-based thin film layer on at least a portion of a substrate; a step (S2) of coating polymethyl methacrylate (PMMA) on the substrate on which the carbon-based thin film layer is formed to form a PMMA thin film layer; a step (S3) of patterning the PMMA thin film layer; a step (S4) of etching the carbon-based thin film layer to form an intermediate structure including a portion where only the patterned PMMA thin film layer exists and a portion where the patterned PMMA thin film layer and the patterned carbon-based thin film layer are bonded; a step (S5) of etching the substrate on which the intermediate structure is formed to form a support portion that supports the intermediate structure; and a step (S6) of applying energy to at least a portion of the patterned PMMA thin film layer to bend the intermediate structure.

[0025] The method for manufacturing a carbon-based microstructure according to the present invention can manufacture various and sophisticated three-dimensional carbon-based microstructures by controlling the bending and folding of a carbon-based thin film layer.

[0026] The method for manufacturing a carbon-based microstructure according to the present invention enables precise structural control by observing and controlling the degree of bending and folding of a carbon-based thin film layer in-situ.

[0027] According to one embodiment of the present invention, the carbon-based microstructure may be a structure that simultaneously implements bidirectional bending within a single structure.

[0028] According to one embodiment of the present invention, the carbon-based microstructure may be a structure including one or more folded portions.

[0029] According to one embodiment of the present invention, the carbon-based microstructure may include a PMMA thin film layer and a carbon-based thin film layer. Specifically, the carbon-based microstructure may include a portion where the PMMA thin film layer and the carbon-based thin film layer are bonded together and a portion where only the PMMA thin film layer exists. According to one embodiment of the present invention, when a process of removing the PMMA thin film layer from the carbon-based microstructure is further performed, the carbon-based microstructure may be formed of a carbon-based thin film layer.

[0030] Hereinafter, each step of the present invention will be described in more detail.

[0031] Step (S1) of forming a carbon-based thin film layer on at least a portion of the substrate

[0032] The above substrate is etched in the S5 step described below to form a support portion, and the type of the above substrate is not particularly limited.

[0033] More specifically, the substrate may be a silicon (Si) substrate. If the substrate is a silicon substrate, by isotropically etching the silicon substrate using xenon difluoride gas in step S5 described below, the carbon-based thin film layer has nearly infinite etching resistance to the xenon difluoride gas, so that the silicon substrate, excluding the support portion, can be etched without damaging the carbon-based thin film layer.

[0034] According to one embodiment of the present invention, the carbon-based thin film layer may include graphene or an amorphous carbon atomic layer.

[0035] According to one embodiment of the present invention, the thickness of the carbon-based thin film layer may be 0.3 nm to 100 nm. More specifically, the thickness of the carbon-based thin film layer may be 0.3 nm to 50 nm, 0.3 nm to 20 nm, 1 nm to 100 nm, 1 nm to 50 nm, or 1 nm to 20 nm.

[0036] The step of forming a carbon-based thin film layer on a portion of the substrate may be performed by a step of transferring a pre-patterned carbon-based thin film layer onto the substrate, or by a step of synthesizing a carbon-based thin film layer covering the entire surface of the substrate and a step of patterning the synthesized carbon-based thin film layer.

[0037] Specifically, the step of synthesizing a carbon-based thin film layer covering the entire surface of the substrate may be performed by chemical vapor deposition (CVD) or sputtering, but is not particularly limited thereto. When the carbon-based thin film layer is synthesized by chemical vapor deposition (CVD) or sputtering, a thin and uniformly thick carbon-based thin film layer can be obtained, and the thickness of the carbon-based thin film layer can be easily controlled.

[0038] Specifically, the step of patterning the synthesized carbon-based thin film layer may be to form a pattern layer on the synthesized carbon-based thin film layer using a lithography method and perform a reactive ion etching (RIE) process using the pattern layer as a mask.

[0039] By performing a step of forming a carbon-based thin film layer on a portion of the substrate, the substrate on which the carbon-based thin film layer is formed can include a portion where the carbon-based thin film layer exists and a portion where the carbon-based thin film layer does not exist, and by forming a PMMA thin film layer in the step S2 described below, a thin film having a two-layer structure in which a PMMA thin film layer and a carbon-based thin film layer are bonded is formed on the portion where the carbon-based thin film layer exists, and a PMMA thin film is formed on the substrate on a portion where the carbon-based thin film layer does not exist.

[0040] Step (S2) of forming a PMMA thin film layer by coating polymethyl methacrylate (PMMA) on the substrate on which the carbon thin film layer is formed

[0041] Polymethyl methacrylate (PMMA) is subjected to energy irradiation by electron beam or laser irradiation, whereby the polymer main chain is cleaved, and the methacryloyl groups contained in the side chains of the PMMA are decomposed by the energy, releasing gases such as CO2 and CH4. The PMMA at the portion where energy is applied by the two reactions can undergo shrinkage. The stress gradient in the thickness direction of the PMMA thin film layer induced by the shrinkage of the PMMA can cause the intermediate structure including the patterned PMMA thin film layer and the portion where the patterned PMMA thin film layer and the patterned carbon thin film layer are bonded to bend.

[0042] The method for coating the above PMMA is not particularly limited, and may be performed by, for example, spin-coating, drop casting, or ink-jet printing.

[0043] According to one embodiment of the present invention, the PMMA thin film layer may be formed directly on the substrate or formed on a carbon-based thin film layer formed on the substrate.

[0044] According to one embodiment of the present invention, the thickness of the PMMA thin film layer may be 50 nm to 2000 nm. More specifically, the thickness of the PMMA thin film layer may be 50 nm to 1500 nm, 50 nm to 1000 nm, 100 nm to 2000 nm, 100 nm to 1500 nm, or preferably 100 nm to 1000 nm.

[0045] Step (S3) of patterning the above PMMA thin film layer

[0046] According to one embodiment of the present invention, the step of patterning the PMMA thin film layer can be performed by electron beam lithography or photolithography.

[0047] The above patterned PMMA thin film layer can have various pattern designs depending on the design of the carbon-based microstructure to be manufactured. For example, microscopic holes can be formed in the portion of the carbon-based microstructure where folding is desired.

[0048] A step (S4) of etching the carbon-based thin film layer to form an intermediate structure including a portion where only the patterned PMMA thin film layer exists and a portion where the patterned PMMA thin film layer and the patterned carbon-based thin film layer are bonded.

[0049] According to one embodiment of the present invention, etching the carbon-based thin film layer can be performed by reactive ion etching (RIE) using the patterned PMMA thin film layer as an etching mask.

[0050] The carbon-based thin film layer in an area not covered by the patterned PMMA thin film layer can be removed by the reactive ion etching (RIE), and thus a pattern identical to the pattern formed in the patterned PMMA thin film layer can be patterned in the carbon-based thin film layer.

[0051] According to one embodiment of the present invention, the reactive ion etching (RIE) may use oxygen plasma and / or hydrogen plasma.

[0052] The above intermediate structure includes a portion where only the patterned PMMA thin film layer exists and a portion where the patterned PMMA thin film layer and the patterned carbon thin film layer are bonded, so that in step S6 described below, it is possible to implement a microstructure in which the bending directions of the portion where only the patterned PMMA thin film layer exists and the portion where the patterned PMMA thin film layer and the patterned carbon thin film layer are bonded are opposite.

[0053] According to one embodiment of the present invention, the intermediate structure may include a corner portion having fine holes formed in a patterned PMMA thin film layer and a patterned carbon-based thin film layer. The corner portion included in the intermediate structure may form a fold portion that is folded by the energy applied in step S6. Specifically, in step S6 described below, a bending deformation that rotates the corner portion about an axis occurs by the energy applied to the patterned PMMA thin film layer, thereby allowing the intermediate structure to fold.

[0054] According to one embodiment of the present invention, the corner portion may have one or more fine holes formed in the patterned PMMA thin film layer and the patterned carbon-based thin film layer. Since the corner portion includes the fine holes, the PMMA weight per area of ​​the corner portion may be relatively small compared to other portions of the patterned PMMA thin film layer, and therefore, even if the same amount of energy is applied to the entire area of ​​the intermediate structure including the corner portion in the step S6 described below, more bending may be induced in the corner portion, so that a fold may be formed.

[0055] Step (S5) of forming a support member that supports the intermediate structure by etching the substrate on which the intermediate structure is formed

[0056] According to one embodiment of the present invention, the substrate on which the intermediate structure is formed can be etched and removed except for a portion that supports the intermediate structure.

[0057] According to one embodiment of the present invention, the etching may be isotropic etching. Since the etching is isotropic etching, an undercut may occur, so the substrate below the intermediate structure may be etched and removed.

[0058] According to one embodiment of the present invention, when the substrate is a silicon substrate, the etching may be dry etching using an etching gas containing fluorine. When the substrate is a silicon substrate and the etching is non-plasma dry etching using an etching gas containing fluorine, the etching is isotropic etching, so the substrate under the intermediate structure can be etched and removed, and there may be no damage to the carbon-based thin film layer due to the etching.

[0059] The substrate on which the intermediate structure is formed is etched and removed except for the support portion that supports the intermediate structure, so that the patterned PMMA thin film layer and carbon-based thin film layer can be bent in the area except for the portion in contact with the support portion in the step S6 described below.

[0060] According to one embodiment of the present invention, when the area of ​​the intermediate structure is large and the substrate under the intermediate structure is not sufficiently etched by undercutting by isotropic etching, the remaining substrate except for the support portion can be etched and removed by forming an opening in the intermediate structure.

[0061] Step (S6) of bending the intermediate structure by applying energy to at least a portion of the patterned PMMA thin film layer

[0062] The above step S6 can bend the intermediate structure by applying energy to at least a portion of the patterned PMMA thin film layer to induce shrinkage in the PMMA region where the energy is absorbed.

[0063] According to one embodiment of the present invention, applying energy to at least a portion of the patterned PMMA thin film layer may be by electron beam irradiation or laser irradiation.

[0064] According to one embodiment of the present invention, in the step S6, when the depth from the surface of a point where 90% or more of the energy absorbed by at least a portion of the patterned PMMA thin film layer is absorbed is more than half of the depth of the thickness of the patterned PMMA thin film layer, a portion where only the patterned PMMA thin film layer exists and a portion where the patterned PMMA thin film layer and the patterned carbon-based thin film layer are bonded can be bent in opposite directions.

[0065] More specifically, when the depth from the surface of a point where 90% or more of the energy absorbed by at least a portion of the patterned PMMA thin film layer is absorbed is more than half of the depth of the thickness of the patterned PMMA thin film layer, the portion where only the patterned PMMA thin film layer exists can be bent in a downward direction of the patterned PMMA thin film layer, and the portion where the patterned PMMA thin film layer and the patterned carbon-based thin film layer are bonded can be bent in an upward direction of the patterned PMMA thin film layer.

[0066] According to another embodiment of the present invention, in the step S6, when the depth from the surface of a point where 90% or more of the energy absorbed by at least a portion of the patterned PMMA thin film layer is absorbed is less than half the depth of the thickness of the patterned PMMA thin film layer, a portion where only the patterned PMMA thin film layer exists and a portion where the patterned PMMA thin film layer and the patterned carbon-based thin film layer are bonded can be bent in the same direction.

[0067] According to one embodiment of the present invention, when the step S6 is performed by electron beam irradiation, the depth from the surface of the point where 90% or more of the energy absorbed by at least a portion of the patterned PMMA thin film layer is absorbed can be controlled by controlling the acceleration voltage of the electron beam. More specifically, as the intensity of the acceleration voltage of the electron beam increases, the depth at which the electron beam energy reaches in the thickness direction of the PMMA thin film layer increases.

[0068] According to one embodiment of the present invention, when the step S6 is performed by laser irradiation, the wavelength of the laser can be adjusted to control the depth from the surface of the point where 90% or more of the energy absorbed by at least a portion of the patterned PMMA thin film layer is absorbed.

[0069] Therefore, by controlling the conditions of laser irradiation or electron beam irradiation in the step S6, and controlling the depth from the surface of the point where 90% or more of the energy absorbed by at least a portion of the patterned PMMA thin film layer is absorbed, the direction of bending of the patterned PMMA thin film layer and the patterned carbon-based thin film layer can be controlled, and a carbon-based microstructure that implements bidirectional bending simultaneously within one structure can be manufactured.

[0070] The acceleration voltage of the electron beam or the wavelength of the laser to reverse the direction of bending of the portion where only the patterned PMMA thin film layer exists in the above intermediate structure and the portion where the patterned PMMA thin film layer and the patterned carbon thin film layer are bonded may vary depending on the thickness of the patterned PMMA thin film layer.

[0071] Preferably, applying energy to at least a portion of the patterned PMMA thin film layer can be performed using an electron beam irradiation device.

[0072] The above electron beam irradiation device is not particularly limited as long as it is a device capable of irradiating a target material with an electron beam by emitting and accelerating an electron beam. For example, a scanning electron microscope or electron beam lithography equipment can be used as the electron beam irradiation device.

[0073] According to one embodiment of the present invention, the acceleration voltage of the electron beam irradiated to at least a portion of the patterned PMMA thin film layer of the intermediate structure may be 0.1 kV or more and 30 kV or less, 1 kV or more and 30 kV or less, 0.1 kV or more and 15 kV or less, 1 kV or more and 15 kV or less, 0.1 kV or more and 10 kV or less, or 1 kV or more and 10 kV or less, and preferably 1 kV or more and 10 kV or less. By irradiating the electron beam to at least a portion of the patterned PMMA thin film layer of the intermediate structure with an acceleration voltage satisfying the above range, deformation such as bending or folding of the intermediate structure may easily occur.

[0074] According to one embodiment of the present invention, the acceleration voltage of the electron beam for reversing the direction of bending of the portion where only the patterned PMMA thin film layer exists in the intermediate structure and the portion where the patterned PMMA thin film layer and the patterned carbon-based thin film layer are bonded may be greater than the acceleration voltage of the electron beam irradiated to at least a portion of the patterned PMMA thin film layer when the depth from the surface of the point where 90% or more of the electron beam energy absorbed by at least a portion of the patterned PMMA thin film layer by the irradiation of the electron beam is absorbed is 1 / 2 of the thickness of the patterned PMMA thin film layer.

[0075] According to one embodiment of the present invention, when the depth from the surface of a point where 90% or more of the electron beam energy absorbed by at least a portion of the patterned PMMA thin film layer by irradiation of the electron beam is absorbed is 1 / 2 of the thickness of the patterned PMMA thin film layer, the acceleration voltage can be determined through an experimental method or Monte Carlo simulation.

[0076] According to one embodiment of the present invention, when the thickness of the patterned PMMA thin film layer is 100 nm to 1000 nm, the acceleration voltage of the electron beam for reversing the direction of bending of a portion where only the patterned PMMA thin film layer exists in the intermediate structure and a portion where the patterned PMMA thin film layer and the patterned carbon-based thin film layer are bonded may be 3 kV to 30 kV, 5 kV to 30 kV, 3 kV to 20 kV, 5 kV to 20 kV, 3 kV to 15 kV, 5 kV to 15 kV, 3 kV to 10 kV, 5 kV to 10 kV, 3 kV to 7 kV, or 5 kV to 7 kV. For example, when the thickness of the patterned PMMA thin film layer is 500 nm, the acceleration voltage may be 5 kV.

[0077] According to one embodiment of the present invention, the time for irradiating the electron beam to at least a portion of the patterned PMMA thin film layer of the intermediate structure may be 0.1 seconds or longer. Even if the time for irradiating the electron beam is increased infinitely, after a certain period of time, there is a limit to the volume shrinkage that occurs in the PMMA thin film layer due to the electron beam irradiation, and additional bending of the patterned PMMA thin film layer does not occur. Therefore, the upper limit of the time for irradiating the electron beam is not particularly limited, and the time for irradiating the electron beam can be adjusted depending on the degree of bending that is to be implemented.

[0078] According to one embodiment of the present invention, as the time for irradiating an electron beam to at least a portion of the patterned PMMA thin film layer of the intermediate structure increases, the degree to which the intermediate structure is bent by the electron beam may increase. Accordingly, the degree of bending of the intermediate structure can be controlled by controlling the time for irradiating an electron beam to at least a portion of the patterned PMMA thin film layer.

[0079] Step of removing PMMA thin film layer from carbon microstructure

[0080] A method for manufacturing a carbon-based microstructure according to one embodiment of the present invention may further include performing a step (S6) of applying energy to at least a portion of the patterned PMMA thin film layer to bend the intermediate structure, thereby obtaining a carbon-based microstructure including a PMMA thin film layer and a carbon-based thin film layer, and then removing the PMMA thin film layer from the carbon-based microstructure. When the step of removing the PMMA thin film layer from the carbon-based microstructure is further performed, the carbon-based microstructure may be formed of a carbon-based thin film layer.

[0081] Figure 2 is a drawing schematically showing each step of a method for manufacturing a carbon-based microstructure according to one embodiment of the present invention.

[0082] Referring to parts (a) to (d) of FIG. 2, a carbon-based thin film layer (20) is formed on at least a portion of a substrate (10), and PMMA is coated on the substrate (10) on which the carbon-based thin film layer (20) is formed, thereby forming a PMMA thin film layer (30). Then, a step of patterning the PMMA thin film layer (30) and a step of etching the carbon-based thin film layer (20) are sequentially performed to form an intermediate structure including a portion where only the patterned PMMA thin film layer (21) exists and a portion where the patterned PMMA thin film layer (21) and the patterned carbon-based thin film layer (31) are bonded. Then, the substrate (10) is etched to remove the substrate except for the support member (11) that supports the intermediate structure.

[0083] Part (e-1) of FIG. 2 shows a case where the depth from the surface of a point where 90% or more of the energy absorbed by at least a portion of the patterned PMMA thin film layer in the step S6 is absorbed is less than half the depth of the thickness of the patterned PMMA thin film layer, and the part where only the patterned PMMA thin film layer exists and the part where the patterned PMMA thin film layer and the patterned carbon thin film layer are bonded can be bent in the same direction.

[0084] Part (e-2) of FIG. 2 shows a case where the depth from the surface of a point where 90% or more of the energy absorbed by at least a portion of the patterned PMMA thin film layer in the step S6 is absorbed is more than half of the depth of the thickness of the patterned PMMA thin film layer, and the part where only the patterned PMMA thin film layer exists and the part where the patterned PMMA thin film layer and the patterned carbon thin film layer are bonded can be bent in opposite directions.

[0085] Hereinafter, the present invention will be described in detail using examples. However, the examples according to the present invention may be modified in various ways, and the scope of the present invention is not limited to the examples described below. The examples in this specification are provided to more fully explain the present invention to those of ordinary skill in the art.

[0086] <Example 1>

[0087] Step (S1) of forming a carbon-based thin film layer on at least a portion of the substrate

[0088] A graphene thin film was synthesized on a silicon substrate using chemical vapor deposition (CVD). Specifically, the substrate was placed in a reaction chamber, hydrogen (H2) gas was supplied, and the temperature was increased to 1020°C at a rate of about 16.6°C / min. Then, methane (CH4) and hydrogen (H2) gas were supplied and synthesis was performed for 120 minutes, thereby synthesizing a graphene thin film layer with a thickness of about 1.5 to 2 nm on the Si substrate.

[0089] Then, a photosensitive pattern layer was formed on the synthesized graphene film layer, and reactive ion etching was performed using this as a mask. Specifically, using a reactive ion etching device (RIE-10NR from Samco), carbon tetrafluoride (CF4) gas was flowed at a flow rate of 20 sccm and the graphene film layer was etched at a power of 30 W for 3 minutes, thereby forming a graphene film layer on a portion of the substrate.

[0090] Step (S2) of forming a PMMA thin film layer by coating polymethyl methacrylate (PMMA) on a substrate on which a carbon thin film layer is formed, and step (S3) of patterning the PMMA thin film layer.

[0091] A polymethyl methacrylate (PMMA) solution (950 PMMA A6) was coated on a substrate having a graphene thin film layer formed on the above-mentioned portion to form a PMMA thin film layer having a thickness of approximately 500 nm. Then, in order to pattern the PMMA thin film layer, an electron beam was irradiated on the area to be removed using a field emission scanning electron microscope (MIRA3 XMH from TESCAN). Thereafter, a patterned PMMA thin film layer was formed using a developer.

[0092] A step (S4) of etching the carbon-based thin film layer to form an intermediate structure including a portion where only the patterned PMMA thin film layer exists and a portion where the patterned PMMA thin film layer and the patterned carbon-based thin film layer are bonded.

[0093] The above patterned PMMA thin film layer was used as an etching mask, and a reactive ion etching device (RIE-10NR from Samco) was used to etch the graphene thin film layer at a power of 30 W for 3 minutes while flowing carbon tetrafluoride (CF4) gas at a flow rate of 20 sccm to obtain a patterned graphene thin film layer.

[0094] Step (S5) of forming a support member that supports the intermediate structure by etching the substrate on which the intermediate structure is formed

[0095] Using the above patterned graphene thin film layer as an etching mask, a dry etching process using xenon difluoride (XeF2) gas was performed. A XeF2 etching device (VPE-4F from SAMCO) was used, and the etching gas pressure (P XeF2 )= 3 torr, processing time (t) exposure ) was etched at room temperature (approximately 20 °C) for approximately 5 minutes to remove the substrate except for the support portion.

[0096] Step (S6) of bending the intermediate structure by applying energy to at least a portion of the patterned PMMA thin film layer

[0097] Carbon-based microstructures were fabricated by inducing bending and / or folding in an intermediate structure including a portion where only a patterned PMMA thin film layer is present on a support and a portion where the patterned PMMA thin film layer and the patterned carbon-based thin film layer are bonded. Unless otherwise specified below, an electron beam was irradiated to the entire area of ​​the patterned PMMA thin film layer included in the intermediate structure. The electron beam was irradiated at an acceleration voltage of 2 kV or 5 kV in SE2 mode using a scanning electron microscope (SUPRA 55VP), and the irradiation time was controlled in the range of 1 second to 2 minutes.

[0098]

[0099] SEM images of carbon-based microstructures manufactured by variously changing the pattern shape of the intermediate structure using the method of Example 1 were taken using a scanning electron microscope (SUPRA 55VP).

[0100] Figure 3 is a SEM image showing the intermediate structure with a butterfly-shaped pattern formed thereon being bent when an electron beam is irradiated on the intermediate structure at an accelerating voltage of 2 kV.

[0101] Referring to Fig. 3, when an electron beam was irradiated at an acceleration voltage of 2 kV on an intermediate structure having a butterfly-shaped pattern formed at the point where a patterned PMMA thin film layer and a patterned carbon thin film layer were bonded, it was confirmed that the intermediate structure where the PMMA thin film layer and the carbon thin film layer were bonded was bent in the upward direction of the PMMA thin film layer. In addition, it was confirmed that as the electron beam irradiation time increased (as it went toward the right figure), the degree of bending of the intermediate structure gradually increased.

[0102] Figure 4 is a SEM image showing bending induced only in a specific part of the intermediate structure by irradiating an electron beam on a specific part of the patterned PMMA thin film layer of the intermediate structure.

[0103] Referring to Fig. 4, it was confirmed that by partially irradiating an electron beam to a portion of an intermediate structure in which a patterned PMMA thin film layer and a patterned carbon thin film layer are bonded, bending of the intermediate structure can be partially implemented only in the area irradiated with the electron beam.

[0104] Figure 5 is an SEM image showing the appearance of the intermediate structure being bent when irradiated with an electron beam at an acceleration voltage of 2 kV and 5 kV for a portion (a) where only the patterned PMMA thin film layer of the intermediate structure exists and a portion (b) where the patterned PMMA thin film layer and the patterned carbon thin film layer are bonded.

[0105] Referring to Fig. 5, it was confirmed that the portion where only the patterned PMMA thin film layer exists was bent upwards with respect to the PMMA thin film layer when the electron beam was irradiated with an acceleration voltage of 2 kV, whereas the portion where the electron beam was irradiated with an acceleration voltage of 5 kV was bent downwards with respect to the PMMA thin film layer. In contrast, it was confirmed that the portion where the patterned PMMA thin film layer and the patterned carbon-based thin film layer were bonded were bent upwards with respect to the PMMA thin film layer when the electron beam was irradiated with an acceleration voltage of 2 kV and 5 kV. In other words, it was confirmed that the directions of bending were reversed when the electron beam was irradiated with an acceleration voltage of 5 kV with respect to the portion where only the patterned PMMA thin film layer exists and the portion where the patterned PMMA thin film layer and the patterned carbon-based thin film layer were bonded.

[0106] Figures 6a, 6b and 6c are schematic diagrams and SEM images showing the simultaneous implementation of bidirectional bending within a single structure by irradiating an electron beam with an acceleration voltage of 5 kV on an intermediate structure including a portion where only a PMMA thin film layer exists and a portion where a patterned PMMA thin film layer and a patterned carbon thin film layer are bonded.

[0107] As shown in FIGS. 6a, 6b, and 6c, it was confirmed that a three-dimensional structure in which bidirectional bending is simultaneously implemented within a single structure can be formed by irradiating an electron beam at an acceleration voltage of 5 kV on an intermediate structure including a portion where only a PMMA thin film layer exists and a portion where a patterned PMMA thin film layer and a patterned carbon thin film layer are bonded.

[0108] Figure 7a is a schematic diagram showing the formation of a carbon microstructure in a cubic structure by irradiating an electron beam to a corner portion included in an intermediate structure in which a pattern in the shape of a cubic development diagram has been formed.

[0109] Figure 7b is an optical microscopy image of an intermediate structure formed in the shape of a cubic development diagram by the method of Example 1.

[0110] Figure 7c is a SEM image showing the formation of a carbon-based microstructure in a cubic shape by irradiating an electron beam at an acceleration voltage of 2 kV on the corner of an intermediate structure that has formed a pattern in the shape of a cubic development diagram.

[0111] Referring to FIGS. 7a to 7c, it was confirmed that the intermediate structure has a pattern in the shape of a development diagram of a regular hexahedron, and that the intermediate structure includes corners with a relatively small PMMA weight per area compared to other regions, including microscopic holes, so that a fold is formed by electron beam irradiation on the corners included in the intermediate structure, and as a result, the intermediate structure, which is a development diagram of a two-dimensional plane, can be folded to form a three-dimensional structure, a regular hexahedron.

[0112] Although the present invention has been described above through limited embodiments, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0113] [Explanation of symbols]

[0114] 10: Substrate

[0115] 20: Carbon-based thin film layer

[0116] 30: PMMA thin film layer

[0117] 11: Support

[0118] 21: Patterned carbon-based thin film layer

[0119] 31: Patterned PMMA thin film layer

Claims

1. A step of forming a carbon-based thin film layer on at least a portion of a substrate; A step of forming a PMMA thin film layer by coating polymethyl methacrylate (PMMA) on a substrate on which the carbon-based thin film layer is formed; A step of patterning the above PMMA thin film layer; A step of etching the carbon-based thin film layer to form an intermediate structure including a portion where only a patterned PMMA thin film layer exists and a portion where the patterned PMMA thin film layer and the patterned carbon-based thin film layer are bonded; A step of etching the substrate on which the intermediate structure is formed to form a support portion that supports the intermediate structure; and A method for manufacturing a carbon-based microstructure, comprising the step of applying energy to at least a portion of the patterned PMMA thin film layer to bend the intermediate structure.

2. In claim 1, A method for manufacturing a carbon-based microstructure, wherein the PMMA thin film layer is formed directly on the substrate or on a carbon-based thin film layer formed on the substrate.

3. In claim 1, In the step of bending the intermediate structure by applying energy to at least a portion of the patterned PMMA thin film layer, The depth from the surface of the point where at least 90% of the energy absorbed by at least a portion of the patterned PMMA thin film layer is absorbed is at least half the depth of the thickness of the patterned PMMA thin film layer, A method for manufacturing a carbon-based microstructure, wherein a portion where only the patterned PMMA thin film layer exists and a portion where the patterned PMMA thin film layer and the patterned carbon-based thin film layer are bonded are bent in opposite directions.

4. In claim 1, A method for manufacturing a carbon-based microstructure, wherein the step of bending the intermediate structure by applying energy to at least a portion of the patterned PMMA thin film layer is performed by electron beam irradiation.

5. In claim 4, A method for manufacturing a carbon-based microstructure, wherein the acceleration voltage of an electron beam irradiated to at least a portion of the patterned PMMA thin film layer is 0.1 kV or more and 30 kV or less.

6. In claim 4, The acceleration voltage of the electron beam irradiated on at least a portion of the patterned PMMA thin film layer is greater than the acceleration voltage when the depth from the surface of the point where 90% or more of the electron beam energy absorbed by at least a portion of the patterned PMMA thin film layer by the irradiation of the electron beam is absorbed is 1 / 2 of the thickness of the patterned PMMA thin film layer. A method for manufacturing a carbon-based microstructure, wherein only the patterned PMMA thin film layer exists and the patterned PMMA thin film layer and the patterned carbon-based thin film layer are bent in opposite directions.

7. In claim 3 or claim 6, The portion where only the patterned PMMA thin film layer exists is bent downwards from the patterned PMMA thin film layer, A method for manufacturing a carbon-based microstructure, wherein a portion where the patterned PMMA thin film layer and the patterned carbon-based thin film layer are bonded is bent in the upward direction of the patterned PMMA thin film layer.

8. In claim 6, The thickness of the above patterned PMMA thin film layer is 100 nm to 1000 nm, A method for manufacturing a carbon-based microstructure, wherein the above acceleration voltage is 3 kV to 30 kV.

9. In claim 1, A method for manufacturing a carbon-based microstructure, wherein the carbon-based thin film layer includes a graphene or amorphous carbon atomic layer.

10. In claim 1, A method for manufacturing a carbon-based microstructure, wherein etching the carbon-based thin film layer is performed by reactive ion etching (RIE) using the patterned PMMA thin film layer as an etching mask.

11. In claim 1, The above intermediate structure includes a corner portion having fine holes formed in a patterned PMMA thin film layer and a patterned carbon thin film layer, A method for manufacturing a carbon-based microstructure, wherein the corner portion is formed by applying energy to at least a portion of the patterned PMMA thin film layer to bend the intermediate structure.

12. In claim 1, A step of applying energy to at least a portion of the patterned PMMA thin film layer to bend the intermediate structure is performed to obtain a carbon-based microstructure including a PMMA thin film layer and a carbon-based thin film layer, and then, A method for manufacturing a carbon-based microstructure, further comprising a step of removing a PMMA thin film layer from the carbon-based microstructure.

13. A carbon-based microstructure manufactured by the method according to claim 1.

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