KR20210107945A - Preparation method of large-area graphene thin films by using energy-beam irradiation - Google Patents

Abstract

The present invention relates to a method for preparing a low-defect graphene thin film with a large area by using linear energy beams and a metal catalyst. The method can be applied to a pellicle material based on graphene having a thickness of 20-50 nm, which is the biggest huddle of the ultra UV exposure technology. Besides the pellicle material, the method according to the present invention can also be applied to the next-generation technologies, such as encapsulation of a flexible display, electrodes of a touch panel, semiconductors (e.g., high-speed transistors), conductive ink, high-efficiency solar cells, secondary batteries, vehicles, lightings, touch panels, heat radiation films, various coating materials, ultrathin speakers, seawater desalination filters, ultrafast chargers, or the like.

Description

Preparation method of large-area graphene thin films by using energy-beam irradiation

The present invention relates to a method for manufacturing a large-area graphene thin film using energy beam irradiation.

Graphene is one of the allotropes of carbon, and has a structure in which carbon atoms are gathered to form a two-dimensional plane. The graphene has high intrinsic electron movement, thermal conductivity and specific surface area, and is transparent due to low absorption of visible light. In particular, as it has unique electrical properties that cannot be obtained from other materials, it is receiving great attention in the semiconductor industry.

The application fields of graphene are very wide, for example, encapsulation of flexible displays, electrodes of touch panels, semiconductors (eg, high-speed transistors), conductive inks, high-efficiency solar cells, secondary batteries, automobiles, lighting, touch It can be applied to next-generation advanced technologies such as panels, heat-dissipating films, various coating materials, ultra-thin speakers, seawater desalination filters, and ultra-fast chargers.

In particular, as a candidate material suitable for the pellicle material, which is a core material applied to the entire surface of the photomask used in EUV lithography, which is one of the biggest issues in the recent semiconductor process, it has high transmittance and mechanical properties. Excellent graphene is mentioned.

The requirements for graphene to be applied to the above-mentioned next-generation advanced technology must be supported by technologies such as high throughput, process simplification, and cost reduction during the process. However, in the current graphene manufacturing technology, it is still difficult to apply due to the technical limitations of large area.

Various methods have been tried for the manufacture of large-area graphene.

In Korean Patent No. 10-1127742, a silicon layer and a silicon oxide layer are sequentially stacked on a substrate with CH ₄ gas containing carbon, and a laser beam is irradiated thereto to generate the CH ₄ gas at 900 to 2000°C. It is disclosed that by decomposition, graphene can be grown on a substrate by this decomposition. This method can produce a high-quality graphene thin film, but as CH ₄ gas is injected at a high temperature, the process is complicated, high cost is required, and it is difficult to increase throughput. In particular, CH ₄ gas is the main culprit of global warming, so its mass use is limited.

In addition, in order to apply the graphene thin film as a pellicle material, a process of removing the catalyst layer using an etchant and transferring the separated graphene thin film to a desired substrate is required. At this time, wrinkles or defects of the graphene thin film are likely to occur after the transfer process by the etchant used. Moreover, there is a limit in the end because the thickness control is not possible in the transfer process.

Accordingly, a technique for applying a precursor, not a gas, as a graphene source has been proposed. As the precursor, a polymer material is used, which is advantageous in terms of cost, and the thickness of the finally obtained graphene thin film can be controlled according to the coating thickness, so that it is more advantageous to apply as a pellicle material.

Korean Patent Laid-Open No. 10-2013-0104752 discloses that a graphene thin film can be prepared by applying a thin film of an organic material to a substrate, crosslinking it by irradiating radiation, and then carbonizing it at 800 to 1500°C. Although a large-area graphene sheet is possible through this technology, as in the above patent, it is required to perform a carbonization process at a high temperature, so there is a problem of low productivity. Control is also not an easy problem.

Recently, a LIG (Laser Induced Graphene) technology that forms a graphene pattern by coating an organic material, which is a graphene precursor, on a substrate and then irradiating a laser has been proposed. Although this technology has the advantage of a very simple process, it is applied to graphene of a small area, that is, a graphene electrode pattern, and when applied to a large area due to the narrow beam width of the laser, the beam scan must be overlapped, so a high-quality graphene thin film could not get

Republic of Korea Patent No. 10-1127742 (03.09.2012), Graphene manufacturing method using laser, Graphene manufactured thereby, manufacturing apparatus for the same Korean Patent Laid-Open Patent No. 10-2013-0104752 (2013.09.25), method for manufacturing graphene from organic material using radiation and graphene prepared therefrom

The present inventors have conducted research on a method for manufacturing a large-area graphene thin film, but to obtain a high-quality thin film while easily controlling the thickness of the finally obtained graphene thin film, and graphene through energy beam irradiation on a graphene precursor It was confirmed that a high-quality graphene thin film can be manufactured over a large area by forming a catalyst layer before or after coating the graphene precursor and designing an energy beam scan method.

Accordingly, an object of the present invention is to provide a method for manufacturing a large-area graphene thin film.

In order to achieve the above object, the present invention

It provides a method of manufacturing a large-area graphene thin film, comprising irradiating an energy beam after forming a graphene precursor film on a substrate, and forming a catalyst layer before or after forming the graphene precursor film.

The graphene precursor film may be a graphene cured coating film or a carbon deposition layer formed by sputtering or vacuum deposition by coating and curing the graphene precursor solution.

In this case, the substrate is glass, quartz, Pyrex, alumina, zirconia, silicon nitride, silicon carbide, sapphire, polyethylene naphthalate, polyethersulfone, polyimide, polycarbonate, polytetrafluoroethylene, polyethylene terephthalate, polystyrene, poly Vinyl chloride, polyvinylpyrrolidone, polyethylene, polydimethylsiloxane, polymethyl methacrylate (PMMA), rubber, metal plate, Si, Ge, GaAs, InP, InSb, InAs, AlAs, AlSb, CdTe, ZnTe, ZnS, and at least one material selected from the group consisting of ZnSe, CdSe, CdSb, GaP, SiC, Al, or Hg.

In addition, the catalyst layer is a catalyst metal having a (111) plane in the FCC structure, and may be one or more single metals or alloys selected from the group consisting of Al, Cu, Au, Pb, Ni, Pt, and Ag, and has a thickness of 10 It has a range from nm to 10 μm.

The graphene precursor solution includes a graphene precursor and a solvent, and has a concentration of 0.1 to 99.9 wt%.

In this case, the graphene precursor includes one kind of polymer selected from the group consisting of polyimide, polyacrylonitrile, polystyrene, rayon, lignin, pitch, borazine oligomer, and combinations thereof.

The carbon deposition layer may be deposited by a vacuum thin film process of CVD (Chemical Vapor Deposition), PECVD (Plasma Enhanced Chemical Vapor Deposition) or PVD (Physical Vapor Deposition), and in CVD and PECVD, CH ₄ , C ₂ H _{2 ,} etc. In PVD including hydrocarbon gas, and sputtering method and IBD method, it can be deposited using a graphite target.

The cured coating film is formed through thermal curing, and has a thickness of 5 nm to 15 μm.

In addition, the energy beam is performed by disposing electron guns in series or in parallel on the substrate, and then transferring the substrate or energy source in one direction to scan the energy beam, but irradiation energy of 1 eV to 500 KeV on the entire substrate investigate with

At this time, the ambient temperature of the substrate in the region to which the energy beam is irradiated is 20° C. to 800° C., and the working pressure around the substrate is 10 ^-7 to 10 ^-1 Torr.

The method for manufacturing graphene by the energy beam irradiation method according to the present invention not only enables a simple process to manufacture a large-area graphene sheet, but also applies an energy beam to a large area corresponding to the 10th generation display area through the energy beam scanning method. High-Throughput is possible because scanning is possible.

The method can easily control the material and thickness of the film according to the composition, viscosity, coating method, and coating thickness of the graphene precursor solution, so it is easy to control the properties and thickness of the finally obtained graphene thin film, and high quality with few defects thin film can be produced.

Therefore, through the method presented in the present invention, it can be applied to graphene-based pellicle materials with a thickness of 20 nm to 50 nm, which is the biggest difficulty of the conventional extreme ultraviolet exposure technology, so that it is possible to lead a leading role in the development of the semiconductor industry.

1 is a flowchart showing a manufacturing process of a graphene thin film according to an embodiment of the present invention.
2 is a schematic diagram showing a beam shape of an electron gun.
3 is a schematic diagram showing irradiating an energy beam on a large substrate according to an embodiment of the present invention. As shown in Fig. 3, it is possible to not only process a large area by serial connection of a linear beam source, but also connect another linear beam source in parallel to increase the processing speed.
4 is a schematic diagram showing a QQ' cross-section.
5 is a flowchart showing a manufacturing process of a graphene thin film according to another embodiment of the present invention.
6 is a Raman spectrum of the graphene thin film prepared in Example 2. Here, D peak is a Disorder peak, G peak is a graphite peak, and 2D is a typical peak that appears when graphene is formed.
7 is a graph showing X-ray Photoelectron Spectroscopy (XPS) depth profile results in which elements are identified in the depth direction of the graphene thin film when graphene having the 2D peak shown in FIG. 6 is formed according to the results of Example 2;

Hereinafter, embodiments of the present application will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art to which the present application pertains can easily implement them. However, the present application may be embodied in several different forms and is not limited to the embodiments described herein. And in order to clearly explain the present application in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification. In addition, in the drawings for convenience of description, the size of the components may be exaggerated or reduced.

Throughout this specification, when it is said that a member is positioned "on", "on", "on", "under", "under", or "under" another member, this means that a member is positioned on the other member. It includes not only the case where they are in contact, but also the case where another member exists between two members.

Throughout this specification, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

As used herein, the terms “about,” “substantially,” and the like are used in a sense at or close to the numerical value when the manufacturing and material tolerances inherent in the stated meaning are presented, and to aid in the understanding of the present application. It is used to prevent an unconscionable infringer from using the mentioned disclosure in an unreasonable manner. Also, throughout this specification, "step to" or "step to" does not mean "step for".

Throughout this specification, the term "combination of these" included in the expression of the Markush form means one or more mixtures or combinations selected from the group consisting of the components described in the expression of the Markush form, and the components It is meant to include one or more selected from the group consisting of.

Throughout this specification, a reference to “A and/or B” means “A, B, or A and B”

The present invention provides a method of manufacturing a low-defect graphene thin film with a large area while securing high throughput.

As one of the methods for manufacturing a low-defect graphene thin film with a large area, in the present invention, a method by energy beam irradiation is adopted. The energy beam can improve the drawbacks of the graphene thin film in the existing CVD vapor deposition process and the difficulty of process control, and at the same time improve the disadvantages of the laser irradiation process for producing the graphene thin film limited to a narrow area.

The manufacture of a graphene thin film using an energy beam may be performed by forming a coating film including a graphene precursor that can be converted into graphene by an energy beam, and then irradiating the energy beam thereto.

By supplying energy to the graphene precursor through energy beam irradiation, the reactivity and fluidity of each atom in the graphene precursor is increased, and diffusion between atoms in the bulk state on the surface and inside of the coating film occurs. The graphene precursor is a material containing carbon, and an aromatic hexagonal C=C bond is generated by irradiation with an energy beam and is converted into graphene in a thin film state. When applied to an actual process, the method of manufacturing graphene by supplying heat or energy to the graphene precursor without a catalyst layer is not easy to form a graphene thin film. It is practically not manufactured, or even if manufactured, its quality (ie, the occurrence of defects) is very low.

In the present invention, a catalyst layer is applied in addition to the vacuum thin film deposition method of a graphene precursor or carbon in order to produce a graphene thin film with low defects in a large area by irradiating an energy beam, and the type and composition of the graphene precursor are limited and energy The scanning method was optimized when irradiating the beam. As a result, it was possible to easily manufacture a low-defect graphene thin film in a large area and secure high throughput, as well as to easily control the thickness of the final graphene thin film by controlling the thickness of the graphene precursor.

The introduction of the catalyst layer may be applied either before or after the introduction of the graphene precursor.

(Method 1)

Specifically, the graphene thin film having a large area according to an embodiment of the present invention is

(S1) forming a catalyst layer on the substrate;

(S2) forming a graphene precursor film on the catalyst layer; and

(S3) irradiating the energy beam;

(S1) catalyst layer formation step

First, after preparing the substrate 10 , the catalyst layer 20 is formed to have a predetermined thickness ( FIGS. 1A and 1B ).

The substrate 10 may include inorganic materials such as glass, quartz, Pyrex, alumina, zirconia, and sapphire; Polyethylene naphthalate (PEN), polyethersulfone (PES), polyimide (PI), polycarbonate (PC), polytetrafluoroethylene (PTFE), polyethylene terephthalate ( polyethylene terephthalate, PET), polystyrene (PS), polyvinyl chloride (PVC), polyvinylpyrrolidone (PVP), polyethylene (polyethlene, PE), polydimethylsiloxane (PDMS), organic substances such as polymethyl methacrylate (PMMA) and rubber; metal plates such as thin plate stainless; It may be any one of an opaque inorganic substrate such as Si, Ge, GaAs, InP, InSb, InAs, AlAs, AlSb, CdTe, ZnTe, ZnS, ZnSe, CdSe, CdSb, GaP, SiC, Al, or Hg.

The thickness of the substrate is not particularly limited in the present invention, and may vary depending on the application purpose of the large-area graphene thin film. At this time, although the substrate in a flat state is illustrated in the drawing, the shape or shape thereof is not limited, such as a spherical shape, an elliptical shape, a cylindrical shape, a conical shape, a polygonal shape, and an irregular shape.

In particular, the conventional process by CVD, laser beam irradiation, or carbonization for producing a graphene thin film requires a high temperature process, so there is a limit to the use of the substrate 10 , but the energy beam irradiation process of the present invention is sufficiently performed even at room temperature. There is no limit to the use of the substrate 10 as it is possible.

The catalyst layer 20 serves to provide a defect in which the graphene precursor can generate an aromatic hexagonal C=C bond by an energy beam. Accordingly, it is substantially impossible to manufacture the graphene thin film 40 without the formation of the catalyst layer 20 .

The catalyst metal forming the catalyst layer 20 should preferentially be a metal, and should have a specific crystal structure, that is, a face centered cubic (FCC) structure. The crystal structure of the metal includes a body centered cubic lattice (BCC) structure, an FCC structure, and a closed packed hexagonal lattices (HCP) structure, and most metals have one of these crystal lattice structures. In addition, even if it has the same crystal structure, it has different characteristics depending on the crystal plane and the crystal direction. do.

The catalyst layer 20 of the present invention uses a catalyst metal having a (111) plane in the FCC structure. The carbon atoms of the graphene precursor form an aromatic hexagonal C=C bond by the energy beam irradiation, and at this time, the carbon atoms are adsorbed on the surface of the catalyst metal to grow into a graphene thin film. When the surface energy of the catalyst metal is unstable, the rate at which carbon atoms are adsorbed is different, resulting in graphitization of carbon atoms rather than graphene. In the FCC structure of the catalytic metal, the (111) plane has the most stable and uniform surface energy, so that carbon atoms are uniformly settled, enabling stable growth into a graphene thin film.

Preferably, as the catalyst metal, at least one single metal or alloy selected from the group consisting of Al, Cu, Au, Pb, Ni, Pt, and Ag may be used.

The thickness of the catalyst layer 20 is not particularly limited, but may be 10 nm to 10 μm, preferably 20 nm to 1 μm. If the thickness is less than the above range, mechanical strength may be reduced, and on the contrary, if it exceeds the above range, transparency (low light transmittance) is low and a problem may occur in using a transparent electrode, so it is appropriately used within the above range.

The formation of the catalyst layer 20 is not particularly limited in the present invention, and any method capable of forming a uniform thin film over the entire substrate may be used. For example, plating, RF/DC sputtering, ion beam sputtering, chemical vapor deposition (CVD), low pressure chemical vapor deposition (LPCVD), plasma enhanced chemical vapor deposition (PECVD, Plasma Enhanced Chemical Vapor Deposition), vacuum deposition (Vacuum Evaporation), electron beam These include E-beam Evaporation, ion-plating, Pulsed Laser Deposition, and Powder Vacuum Spraying methods.

(S2) Graphene precursor film formation step

Next, a dry coating film 30a is formed by applying a graphene precursor solution on the catalyst layer 20 ( FIG. 1C ). At this time, the dry coating film 30a is different from the subsequent graphene precursor film 30 in an uncured state, that is, in a state in which only the solution is removed.

The graphene precursor solution includes a graphene precursor and a solvent.

The graphene precursor is a polymer, and any one having a graphene structure by energy beam irradiation may be used. Typically, the graphene precursor may be one selected from the group consisting of polyimide, polyacrylonitrile, polymethylmethacrylate, polystyrene, rayon, lignin, pitch, borazine oligomer, and combinations thereof. Among these graphene precursors, an aromatic hydrocarbon series, that is, polyimide, is preferable so that an aromatic hexagonal C=C bond can easily occur by energy beam irradiation. In addition, the polymer is preferably an oligomer so that a subsequent curing process can be performed.

In this case, the properties and types of graphene finally obtained can be controlled by the composition of the graphene precursor. For example, in the case of polyimide or PMMA, it is possible to prepare a graphene thin film having excellent conductivity, and in the case of a borazine oligomer, a white graphene thin film may be prepared.

Any solvent can be used as long as it can sufficiently dissolve the graphene precursor to adjust the viscosity in a predetermined range. The solvent may vary depending on the composition or molecular weight of the graphene precursor, that is, the polymer. For example, dimethylformamide (DMF), formaldehyde, chloroform, dimethylacetamide (DMA), pyridine, benzopyridine (quinoline), benzene, xylene, toluene, dioxane, tetrahydrofuran (THF), diethyl ether, dimethyl sulfoxide (DMSO), n-methyl-2-pyrrolidone (NMP) one selected from the group or It may include two or more types.

If necessary, the graphene precursor solution may further include an additive for controlling dispersibility, coatability, viscosity, etc., and/or a dopant for doping purpose. The type and content range are not particularly limited in the present invention, and may be appropriately selected by those skilled in the art.

The graphene precursor dry coating film 30a using the graphene precursor solution may be formed by drying after performing a conventional wet coating method on the catalyst layer 20 .

At this time, the viscosity of the graphene precursor solution is limited to facilitate coating and to form a uniform dry coating film 30a. Preferably within the range of 100 cps to 10 cps, the lower the viscosity, the lower the coating thickness. If the concentration is less than the above range, it is necessary to go through several coating processes to form the dry coating film 30a of the graphene precursor having a predetermined thickness, and thus it may be difficult to form a uniform dry coating film 30a. Conversely, if the viscosity is too high, the physical properties of the entire cured coating film (30 in FIG. 1D ) obtained after the subsequent curing process may not be uniform, so it is appropriately used within the above range.

The wet coating method may be any one of a roll coating method, a spray coating method, an impregnation coating method, a spin coating method, a gravure coating method, a knife coating method, a bar coating method, a slot die coating method, or a screen printing method, among which In order to facilitate the process and form a uniform coating film, a spray coating method or, in the case of a continuous process, a roll coating method may be used.

After coating the graphene precursor solution on the catalyst layer 20, the solvent is removed by drying. Removal of the solvent may vary depending on the type of solvent used. Usually, hot air drying or induction heating drying method may be used, and it is carried out at 30 ° C. to 90 ° C., 35 ° C. to 85 ° C., 40 ° C. to 80 ° C., and, if necessary, reduced pressure. can be performed.

After drying, a coating film (ie, thick film) of a predetermined thickness is formed on the dried coating film 30a of the graphene precursor on the catalyst layer 20, and heat is applied to cure the graphene precursor. At this time, the temperature varies depending on the type of polymer of the graphene precursor, and in the case of polyimide, it was performed at 400°C.

The cured coating film 30 of the graphene precursor obtained after curing is 5 nm to 15 μm, 20 nm to 14 μm, 50 nm to 14 μm, 100 nm to 13 μm, 100 nm to 10 μm, 0.5 μm to 10 μm, 1 μm to 10 μm. can The thickness of the graphene precursor film 30 can be adjusted to the thickness and thickness of the total graphene thin film (40 in FIG. 1E ) manufactured by the energy beam. If the thickness is too thin, graphene cannot be formed into a stable structure, and if it is too thick, graphitized or multi-layered graphite may be formed.

At this time, although not shown in FIG. 1 in step (S2), a carbon deposition layer may be formed with the graphene precursor 30 film by a dry vacuum coating method.

The carbon deposition layer can be deposited by a vacuum thin film process of CVD (Chemical Vapor Deposition), PECVD (Plasma Enhanced Chemical Vapor Deposition), or PVD (Physical Vapor Deposition), and in CVD and PECVD, hydrocarbon gas including _{CH 4} , C2H _{2 , etc.} In PVD including sputtering method and IBD method, it can be deposited using a graphite target.

At this time, the carbon deposition layer may be formed without a curing process, and has the above-mentioned thickness of the coating film.

(S3) energy beam irradiation step

Next, an energy beam is irradiated to the graphene precursor film 30 formed on the entire substrate 10 to form the graphene thin film 40 on the catalyst layer 20 ( FIG. 1E ).

The energy beam is an ion beam, an electron beam, a laser beam or a neutron beam, preferably an electron beam.

Through the irradiation of the energy beam, graphene is formed from the graphene precursor in contact with the surface of the catalyst metal, and the graphene gradually grows and diffuses to the inside of the coating film. The grown graphene is obtained in the form of a thin film in a dense state that does not include pores or defects, and growth occurs uniformly from the surface of the catalyst layer at a relatively same rate to obtain the graphene thin film 40 having a high degree of smoothness.

In particular, when the energy and flux of the energy beam of the present invention are increased, the processing time can be relatively shortened, so that the graphene thin film 40 with improved properties can be obtained at a much faster rate than the general heat treatment method. In addition, a separate heat treatment, that is, it can be performed without applying heat to the substrate 10, so that a conventional substrate limited by heat can be used without limitation, and a relatively low cost is required in terms of processing.

More specifically, in order to manufacture a large-area graphene thin film, the process conditions of energy beam irradiation are limited.

Irradiation of the energy beam is performed in a vacuum chamber capable of irradiating a known energy beam. In the vacuum chamber, a support is disposed therein, a substrate is mounted on the support, and an energy beam source for irradiating an energy beam to the substrate is disposed.

Among the energy beam sources, the electron beam uses a field emission method to extract electrons by applying a high negative voltage to a sharp tip to generate an electron beam, a thermoelectric method made by heating filaments such as tungsten and LaB6, or a grid shielding plasma A plasma extraction method in which electrons are extracted and accelerated by applying a voltage at the same time may be used.

Among them, the plasma extraction method can be a large source, and by scanning it in the vertical direction of the large substrate, a large area can be uniformly processed. At this time, various types of power source for making plasma, such as LF, MF, HF, RF, UHF, and Microwave, can be used depending on the AC frequency. Also, depending on the shape of the electrode or antenna, Capacitive, Inductive, ICP, ECR, Helical, Helicon Various types such as , hollow cathode, and hot filament can be used, and high pressure plasma such as atmospheric pressure plasma can be used.

Irradiation of the energy beam may be performed while the support is transferred at a constant speed while the energy beam source is fixed, or the energy beam source is transferred while the support is fixed. It is advantageous.

In this case, there may be one or more energy beam sources, and a plurality of energy beam sources are used for a large-area graphene thin film, but these may be arranged in series or in parallel.

2 is a schematic diagram showing the beam shape of the energy beam source, a round gun (FIG. 2a) for generating a circular energy beam according to the cross-sectional shape (ie, spot) of the energy beam source, horizontal and It may be a linear gun (FIG. 2B) that generates a linear energy beam having a different vertical ratio, and the graphene thin film 40 having a large area can be formed through various arrangements thereof. Preferably, as the energy beam source, a linear gun in the form of a long cuboid having a length similar to the width of the substrate may be used.

3 is a schematic diagram showing irradiating an energy beam on a substrate according to an embodiment of the present invention, and FIG. 4 is a schematic diagram showing a Q-Q' cross section. At this time, although the energy beam irradiated in the drawing is illustrated as being irradiated only to a predetermined area, when actually irradiating the energy beam, these energy beams fly while spreading to some extent, so the empty space between the energy beams irradiated by each electron gun is substantially judged to be absent.

Referring to FIG. 3 , after arranging three linear energy beam sources (source1, source2, source3) in series on the substrate 10 on which the catalyst layer 20/graphene precursor film 30 is sequentially formed, By transferring the energy beam source in one direction while irradiating the energy beam in a state in which the substrate 10 is fixed, the energy beam is irradiated over the entire substrate 10 to form a graphene thin film with a large area. As shown in FIG. 3 , it is possible to not only process a large area by serial connection of a linear beam source, but also connect another linear beam source in parallel to increase the processing speed.

In addition, three energy beam sources are arranged in series so that all energy beams can be irradiated to the width of the substrate 10 . At this time, as shown in FIG. 4 , the energy beam is irradiated over the entire substrate 10 by transferring the energy beam source in one direction, and after the irradiation, the graphene precursor film 30 is converted into a graphene thin film.

The method shown in FIGS. 3 and 4 is a method of scanning while transporting the energy beam sources by arranging three preceding energy beam sources in series. This method belongs to one embodiment of the present invention, and the number of energy beam sources and the shape of the energy beam sources may vary depending on the size of the substrate 10 , and the arrangement of the energy beam sources is also a parallel method in addition to the series method. , or a mixture thereof may be made. In addition, although the method of scanning by moving the energy beam source has been described in the above example, a method of transferring the substrate 10 in one direction while the energy beam source is fixed may be used.

When irradiating the energy beam, the transfer speed of the energy beam source or the substrate 10 may provide a sufficient time for the graphene thin film 40 to be sufficiently formed in the graphene precursor film 30 . That is, as the thickness of the graphene precursor layer 30 decreases and the energy of the applied energy beam increases, the transport speed may increase. More specific conditions may be appropriately selected and changed by those skilled in the art.

The energy beam irradiated to the substrate 10 is accelerated to have kinetic energy of 1 eV to 500 keV and 2 KeV to 450 KeV by the applied voltage and is irradiated to the process region on the substrate 10 . If the irradiated energy is less than the above range, it is difficult to manufacture a graphene thin film, and on the contrary, even if energy above the above range is irradiated, there is no significant effect on conversion to graphene, so it is uneconomical, so it is appropriately used within the above range.

The present energy beam irradiation process may occur under various ambient conditions. These ambient conditions include, but are not limited to, temperature, pressure, presence of air, and combinations thereof.

Specifically, the ambient temperature of the substrate in the region to which the energy beam is irradiated is 20° C. to 800° C., 25° C. to 750° C., 25° C. to 500° C., and the working pressure around the substrate is 10 ^-7 to 10 ^-1 Torr. do. If the temperature is above the above range, there is a risk that graphite, not graphene, is generated due to carbonization. In addition, when the pressure is too high, scattering occurs by the particles in the chamber when the energy beam is irradiated and the stability of the beam is reduced, so it is appropriately used within the above range.

In addition, the energy beam irradiation process is performed in the presence of an inert gas, in this case, the inert gas is preferably one or two or more selected from nitrogen, helium, neon, argon, xenon, or a mixture thereof, but not limited thereto. does not

The steps of forming the catalyst layer 20 and the graphene precursor dry thin film 30a and the precursor film 30, including the energy beam irradiation of this step as described above, and the energy beam irradiation are continuously and automatically through a roll-to-roll process. It can be carried out as a single step, or it can be performed separately for each step. As such, one or more steps of the method of the present disclosure may occur automatically, for example, through the use of computer-controlled automated processing lines. For example, it is technically possible to process a large-area graphene through a continuous line after mounting a linear energy beam source in a roll-to-roll vacuum chamber system.

In addition, in order to remove a trace amount of amorphous carbon layer present on the graphene thin film after energy beam irradiation in the above step, a process of irradiating the surface with a hydrogen beam made by plasma etching using hydrogen or hydrogen plasma activation can be further performed. have.

(Method 2)

In addition, the large-area graphene thin film according to another embodiment of the present invention can be performed by irradiating an energy beam after forming a catalyst layer on the graphene precursor film.

Specifically,

(S1) forming a graphene precursor film on the substrate;

(S2) forming a catalyst layer on the graphene precursor film;

(S3) irradiating the energy beam;

Hereinafter, each step will be described in detail with reference to the drawings. 5 is a flowchart showing a manufacturing process of a graphene thin film according to an embodiment of the present invention.

First, referring to FIGS. 5A and 5B , a dry coating film 30a is formed by applying a graphene precursor solution on a substrate 10 .

In this case, a carbon deposition layer may be formed instead of the dry coating film 30a. The carbon deposition layer may be deposited using a vacuum thin film process such as CVD, PECVD or PVD instead of using a precursor coating. The carbon deposition layer is not subsequently cured.

Next, a catalyst layer 20 is formed on the dry coating film 30a (see FIG. 5C ).

Next, a curing process is performed to obtain a graphene precursor film 30 (see FIG. 5D ).

Next, by irradiating an energy beam, the graphene precursor film 30 is obtained as a graphene thin film 40 (see FIG. 5E ).

The specific details of each step follow the above-mentioned implementation examples.

As described above, the graphene thin film 40 prepared in a large area by energy beam irradiation according to the present invention is single-layered graphene, multi-layered graphene, double-layered graphene, triple-layered graphene, doped graphene, and porous graphene. Pines, unfunctionalized graphene, pristine graphene, functionalized graphene, oxidized graphene, turbostratic graphene, and white graphene are all included. In this case, the thin film is made of graphene, and refers to a sheet shape having a two-dimensional planar structure with a size of nanometers to microns.

According to one embodiment of the present invention, the above step may be repeatedly performed two or more times to obtain a multi-layered graphene thin film.

In addition, according to another embodiment of the present invention, a multilayer graphene precursor film may be formed to obtain a multilayer graphene thin film.

In addition, according to another embodiment of the present invention, it is possible to obtain a multi-layered graphene thin film by changing the type of the graphene precursor.

In addition, according to another embodiment of the present invention, it is possible to obtain a structure in which graphene/white graphene are stacked on each other by changing the composition of the graphene precursor coating film.

These various structures can be performed by changing various parameters of the above steps.

The large-area graphene thin film prepared according to the present invention can easily control its properties and thickness depending on the material and thickness of the precursor layer, and is manufactured with high quality, so that wrinkles or defects hardly occur after the transfer process. For example, the thickness ranges from 1 nm to 10 μm, 10 nm to 8 μm, 20 nm to 8 μm, 0.5 μm to 7 μm, and 1 μm to 7 μm.

The graphene thin film 40 may be applied as it is as a substrate, or may be applied to various fields in the form of a sheet by separating the graphene thin film 40 from the catalyst layer 20 . In this case, the separation method may be performed by performing a transfer process through various methods such as a chemical treatment method (eg, etching) or a magnetic field application method.

Preferably, in the present invention, by manufacturing the graphene thin film 40 directly on the substrate 10 through the above-described method, the transfer process is omitted to shorten the manufacturing time of the graphene thin film, and at the same time, in the separation and transfer process Defects in graphene that occur can be minimized.

In addition, the application of graphene is, in addition to the Pellicle material, encapsulation of flexible displays, electrodes of touch panels, semiconductors (eg, high-speed transistors), conductive inks, high-efficiency solar cells, secondary batteries, automobiles, lighting, touch panels, It can be applied to next-generation technologies such as heat dissipation films, various coating materials, ultra-thin speakers, seawater desalination filters, and ultra-fast chargers.

On the other hand, the large-area graphene thin film according to the above-mentioned (first method) and (second method) forms an amorphous silicon layer, so that it is possible to finally prepare a thin film having a graphene/c-Si multilayer structure do.

Deposition of the amorphous silicon layer is performed before the energy beam irradiation.

If (1st method) is followed, after forming the graphene precursor film, an amorphous silicon layer is formed and then the energy beam irradiation step is performed in order, and (2nd method) is followed, an amorphous silicon layer is formed on the catalyst layer After forming the energy beam irradiation step is performed in order.

The deposited amorphous silicon layer is crystallized by energy beam irradiation to form a crystalline silicon layer (c-Si) to form a multilayer thin film or a heterogeneous film having a graphene/c-Si multilayer structure.

When irradiating an energy beam in (Method 2), amorphous silicon is easily crystallized by the catalyst metal, and at the same time, carbon atoms at the bottom of the catalyst metal penetrate the catalyst metal by diffusion to form graphene under the silicon. As a result, a graphene/c-Si or graphene/silicon carbide (SiC)/c-Si structure can be formed.

A multilayer thin film with a graphene/c-Si multilayer structure can be applied to a pellicle for EUV (Extreme Ultra Violet), and it can increase the transmittance to EYV due to the crystalline silicon layer, and at the same time, the weak mechanical properties of silicon is supplemented by graphene, and the transmittance of the EUV pellicle can be improved without reducing the strength of the EUV pellicle due to the mutual complementation between graphene and crystalline silicon.

In particular, since crystallization of silicon by electron beam does not form coarse grain boundaries, unlike the results of laser beam irradiation, a multilayer film with graphene that does not break easily and satisfies excellent strength has excellent mechanical properties required for the pellicle. can be satisfied

Formation of the amorphous silicon layer can be performed by a deposition process, and RF/DC sputtering, ion beam sputtering (IBD), chemical vapor deposition (CVD), low pressure chemical vapor deposition (LPCVD), plasma chemical vapor deposition (PECVD), vacuum deposition (Vacuum Evaporation), E-beam evaporation (E-beam Evaporation), ion plating (ion-plating), Pulsed Laser Deposition, Powder Vacuum Spraying methods and the like are included.

At this time, the thickness of the amorphous silicon layer is formed in the range of 5 nm to 50 nm. The thickness range considers the final thickness of the crystalline silicon layer formed by energy beam irradiation, and means an appropriate thickness to secure optimal physical properties when applied to the EUV pellicle.

There are various methods for forming the crystalline silicon layer, such as the conventional method by laser irradiation of the deposited film, the solid-state crystallization method, and the rapid heat treatment method. It can be said that it is almost impossible to apply. However, in the graphene thin film process as in the present invention, the formation of a graphene/c-Si thin film is possible only by deposition of an amorphous silicon layer and treatment with an energy beam, thereby simplifying the process and having a stable graphene/c-Si multilayer structure. Since it is possible to manufacture a multi-layer thin film, it can be preferably applied to a Pellicle for EUV.

These methods include graphene/c-Si, graphene/c-Si/graphene, c-Si/graphene/c-Si, c-Si/SiC/graphene, c-Si/SiC/graphene/SiC It can be manufactured in the structure of /c-Si, graphene/SiC/c-Si/SiC/graphene.

[Example]

Hereinafter, the present invention will be described in detail through examples. However, the following examples are merely illustrative of the present invention, and the content of the present invention is not limited by the following examples.

(Example 1) Preparation of graphene thin film

A 750 nm thick copper thin film was formed as a catalyst layer on a silicon substrate by CVD. After coating a graphene precursor solution (polyimide/NMP solution, 50cps) on the catalyst layer, drying at 40° C. for 10 minutes, and thermal curing at 400° C. for 20 minutes, a 100 nm thick graphene precursor cured coating film was prepared. Alternatively, instead of using a precursor coating, an amorphous carbon layer was deposited by a vacuum thin film process such as CVD, PECVD, or PVD.

The substrate was transferred into an electron beam deposition chamber, and then an electron beam of 5 Kev was ^{irradiated at room temperature (10 −1} torr) for 20 minutes to prepare a graphene thin film having a thickness of 80 nm.

(Example 2) Preparation of graphene thin film

A graphene precursor solution (polyimide/NMP solution, 50 cps) was coated on a silicon substrate, and then dried at 40° C. for 10 minutes to form a coating film. Alternatively, instead of using a precursor coating, an amorphous carbon layer was deposited by a vacuum thin film process such as CVD, PECVD, or PVD. Here, a nickel thin film with a thickness of 500 nm was formed as a catalyst layer through CVD. Thermal curing was performed at 400° C. for 20 minutes to prepare a 100 nm thick graphene precursor cured coating film.

The substrate was transferred into an electron beam deposition chamber, and then an electron beam of 5 Kev was ^{irradiated at room temperature (10 −1} torr) for 20 minutes to prepare a graphene thin film having a thickness of 80 nm.

(Comparative Example 1)

A graphene thin film was prepared in the same manner as in Example 1, except for forming a catalyst layer.

(result)

As a result of Raman spectrum analysis, it was confirmed that a graphene thin film was not formed in Comparative Example 1.

6 is a Raman spectrum of the graphene thin film of Example 2. Here, D peak is a Disorder peak, G peak is a graphite peak, and 2D is a typical peak that appears when graphene is formed. Referring to FIG. ^{6, 1300cm -1: D peak,} 1580cm -1: with G peak Yes 2700cm ^-1 indicating the pin: have determined the 2D peak, So it can be seen that pin thin film is formed. This trend was also shown in the graphene thin film of Example 1.

7 is a graph showing the X-ray Photoelectron Spectroscopy (XPS) depth profile result in which the elements in the depth direction of the graphene thin film are confirmed when graphene having the 2D peak shown in FIG. 6 is formed according to the results of Example 2;

Referring to FIG. 7 , when the 80 nm graphene thin film was etched from the top, no composition other than graphene was detected, and after 80 nm, the composition of the silicon substrate used as the substrate was detected. From these results, it can be seen that the nickel catalyst used as the catalyst layer is evaporated through carbonization bonding during the energy beam irradiation process, and only graphene remains on the silicon substrate. Through this, it can be seen that it is possible to control the thickness of the graphene thin film formed only by the thickness or content of the graphene precursor cured coating film.

10: substrate
20: catalyst layer
30: graphene precursor film
30a: graphene precursor dry coating film
40: graphene thin film

Claims (15)

In order to prepare a large-area graphene thin film,
A method of manufacturing a large-area graphene thin film, comprising: irradiating an energy beam after forming a graphene precursor film on a substrate; and forming a catalyst layer before or after forming the graphene precursor film.
The method of claim 1
The graphene precursor film is a graphene cured coating film or a carbon deposition layer formed by sputtering or vacuum deposition by curing the graphene precursor solution after coating, a method for producing a large-area graphene thin film.
3. The method of claim 2,
The graphene precursor includes at least one polymer selected from the group consisting of polyimide, polymethyl methacrylate, polyacrylonitrile, polystyrene, rayon, lignin, pitch, borazine oligomer, and combinations thereof, large-area graphene A method for manufacturing a fin thin film.
3. The method of claim 2
The carbon deposition layer is formed by vacuum deposition such as graphene sputtering, Graphite IBD or C ₂ H ₂ , _{CVD using CH 4} gas, PECVD, etc., a method of manufacturing a large-area graphene thin film
According to claim 1,
The substrate is glass, quartz, pyrex, alumina, zirconia, sapphire, polyethylene naphthalate, polyethersulfone, polyimide, polycarbonate, polytetrafluoroethylene, polyethylene terephthalate, polystyrene, polyvinyl chloride, polyvinylpyrrolidone , polyethylene, polydimethylsiloxane, polymethyl methacrylate, rubber, metal plate, Si, Ge, GaAs, InP, InSb, InAs, AlAs, AlSb, CdTe, ZnTe, ZnS, ZnSe, CdSe, CdSb, GaP, SiC, Al , or a method of manufacturing a large-area graphene thin film comprising at least one material selected from the group consisting of Hg.
According to claim 1,
The catalyst layer comprises a catalyst metal having a (111) plane in the FCC structure, a method for producing a large-area graphene thin film.
According to claim 1,
The catalyst layer is one or more single metals or alloys selected from the group consisting of Al, Cu, Au, Pb, Ni, Pt, and Ag, a method for producing a large-area graphene thin film.
According to claim 1,
The catalyst layer has a thickness of 10 nm to 10 μm, a method for producing a large-area graphene thin film.
According to claim 1,
The graphene precursor film has a thickness of 5 nm to 15 μm, a method of manufacturing a large-area graphene thin film.
According to claim 1,
The energy beam is an ion beam, an electron beam, a laser beam or a neutron beam, a method of manufacturing a large-area graphene thin film.
According to claim 1,
The energy beam is a method of manufacturing a large-area graphene thin film irradiated with an irradiation energy of 1eV to 500keV.
According to claim 1,
The energy beam irradiation is a method of manufacturing a large-area graphene thin film in which the energy beam source is disposed on a substrate in series, parallel, or a mixture thereof, and then the substrate or the energy beam source is transferred in one direction to irradiate the entire substrate.
According to claim 1,
The energy beam irradiation is performed under a pressure of 20 ℃ to 800 ℃ and 10 ^-7 to 10 ^-1 Torr, a method for producing a large-area graphene thin film.
According to claim 1,
In addition, a method of manufacturing a large-area graphene thin film by further performing plasma etching using hydrogen or etching the amorphous carbon layer by irradiating the surface with an activated hydrogen beam from hydrogen plasma.
According to claim 1,
In addition, a method for producing a large-area graphene thin film to form an amorphous silicon layer on the substrate / catalyst / (graphene precursor cured coating film) or substrate / (graphene precursor cured coating film) / catalyst layer before the energy beam irradiation.

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