KR101716187B1 - Method for transferring graphene - Google Patents

Abstract

According to an embodiment of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: synthesizing graphene on at least one side of a catalyst metal layer; Attaching a carrier to the graphene to form a first structure; Removing the catalyst metal layer from the first structure to form a second structure; Subjecting the target substrate to a plasma treatment under a condition that a flow rate ratio of oxygen to argon is 0.1 to 0.5; Forming a third structure by pressing the graphene of the second structure facing the target substrate and opposed to each other; And removing the carrier.

Description

{Method for transferring graphene}

To a graphene transfer method of the present invention.

Currently, carbon based materials such as carbon nanotubes, diamond, graphite, and graphene are being studied in a wide variety of nanotechnologies. These materials can be used or used in field effect transistors (FETs), biosensors, nanocomposites or quantum devices.

Graphene is a two-dimensional material with a bandgap of zero (0), a very thin, transparent, electrically conductive material. With this characteristic of graphene, attempts have been made to apply graphene to a transparent display, a display which can be bent, or a transparent electrode of a touch panel. Recently, a large area synthetic method has been developed to commercialize a graphene transparent electrode Research is actively underway.

Since graphene is synthesized on a large area on a wafer or a metal substrate, in order to use graphene in an electronic device, a process of transferring graphene synthesized on a substrate included in an electronic device is essentially required.

After the transferred graphene is applied to an application such as a display including a touch panel and exposed to a high temperature and high humidity environment, the electrical characteristics of the transferred graphene are deteriorated.

Embodiments of the present invention provide a graphene transfer method in which the electrical characteristics of graphene do not deteriorate even in a high temperature and high humidity environment when the graphene is applied to an application such as a display including a touch panel.

According to an embodiment of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: synthesizing graphene on at least one side of a catalyst metal layer; Attaching a carrier to the graphene to form a first structure; Removing the catalyst metal layer from the first structure to form a second structure; Subjecting the target substrate to a plasma treatment under a condition that a flow rate ratio of oxygen to argon is 0.1 to 0.5; Forming a third structure by pressing the graphene of the second structure facing the target substrate and opposed to each other; And removing the carrier.

In this embodiment, the target substrate may be made of polyethylene terephthalate (PET) or glass.

In this embodiment, the step of performing the plasma processing may be performed at atmospheric pressure using a radio frequency.

In this embodiment, the width of the target substrate may be 500 mm or more.

In the present embodiment, the step of performing the plasma treatment may be performed under the condition that the applied power is about 375 W or more.

In the present embodiment, the catalyst metal layer may be formed of at least one selected from the group consisting of Ni, Co, Fe, Pt, Au, Al, Cr, At least one of magnesium (Mg), manganese (Mn), rhodium (Rh), tantalum (Ta), titanium (Ti), tungsten (W), uranium (U), vanadium (V) and zirconium And the carrier may be any one of a heat peeling tape, a silicone tape, an acrylic tape and a polymer coating film.

Other aspects, features, and advantages other than those described above will be apparent from the following detailed description, claims, and drawings.

According to embodiments of the present invention as described above, when the transferred graphene is applied to an application such as a display including a touch panel, the electrical characteristics of graphene do not deteriorate even in a high temperature and high humidity environment, It is possible to provide a graphene transfer method in which conductivity is increased. Of course, the scope of the present invention is not limited by these effects.

1 is a flowchart showing a graphene transfer method according to an embodiment.
2 to 7 are cross-sectional views schematically showing process states of the respective steps of FIG.

Hereinafter, the structure and operation of the graphene transfer method according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, like reference numerals refer to like elements, and the size and thickness of each element may be exaggerated for clarity of explanation.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are not to be construed as limiting for the invention as set forth in the appended claims. And the present invention is only defined by the scope of the claims.

It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. As used in the specification, "comprises" and / or "comprising" do not exclude the presence or addition of the stated components, steps, operations, and / or elements. The terms first, second, etc. may be used to describe various elements, but the elements should not be limited by terms. Terms are used only for the purpose of distinguishing one component from another.

FIG. 1 is a flowchart showing a graphene transferring method according to an embodiment, and FIGS. 2 to 7 are cross-sectional views schematically showing process states in each step of FIG.

1, a graphene transfer method according to an exemplary embodiment of the present invention includes the steps of synthesizing graphene 120 on at least one surface of a catalyst metal layer 110 (S10), forming a carrier 130 on the graphene 120 A step S30 of forming the second structure 20 by removing the catalyst metal layer 110 from the first structure 10, a step of forming a first structure 10 by attaching the target substrate 140, (S40), the graphene 120 of the second structure 20 and the target substrate 140 are opposed to each other and pressed to form a third (S50) of forming the structure (30) and removing the carrier (130) (S60).

Referring to FIG. 2, at step S10 of FIG. 1, a graphene 120 may be formed on at least one surface of the catalyst metal layer 110.

The catalytic metal layer 110 may be formed of a metal such as Ni, Co, Fe, Pt, Au, Al, Cr, Cu, (Mn), Rh, Rh, Ta, Ti, W, U, V, and Zr.

The graphene 120 is synthesized by heat-treating the catalyst metal layer 110 while supplying a gaseous carbon source thereto. The graphene 120 is formed by connecting a plurality of carbon atoms to each other through a covalent bond to form a two-dimensional flat sheet. The carbon atoms connected by a covalent bond form a 6-membered ring as a basic repeating unit, It is also possible to further include a torus. Thus, graphene 120 forms a single layer of covalently bonded carbon atoms (usually sp2 bonds). The graphene 120 may have a variety of structures, and such a structure may vary depending on the content of the five-membered ring and / or the seven-membered ring which may be contained in the graphene 120.

A carbon source in the gaseous methane (CH _4), carbon monoxide (CO), ethane (C ₂ H _6), ethylene (CH _2), ethanol (C ₂ H _5), acetylene (C ₂ H _2), propane (CH ₃ CH ₂ CH _3), propylene (C ₃ H _6), butane (C ₄ H _10), pentane _{(CH 3 (CH 2) 3} CH 3), pentene (C ₅ H _10), dicyclopentadiene (C ₅ H _6), hexane (C ₆ H _14), cyclohexane (C ₆ H _12), benzene (C ₆ H _6), toluene (C ₇ H _8), etc. there are one or more selected from the included carbon atoms the group may be used . Such a gaseous carbon source is separated into carbon atoms and hydrogen atoms at high temperatures.

The separated carbon atoms are deposited on the heated catalyst metal layer 110 and synthesized into the graphene 120 as the catalyst metal layer 110 is cooled.

A chemical vapor deposition (CVD), a thermal chemical vapor deposition (TCVD), a rapid thermal chemical vapor deposition (RTCVD), a rapid thermal chemical vapor deposition (RTCVD) Various processes such as ICP-PECVE (Inductive Coupled Plasma Enhanced Chemical Vapor Deposition) and ALD (Atomic Layer Deposition) may be used.

The graphene 120 may be formed of one layer, but may be formed of a plurality of layers depending on the type of the catalyst metal layer 110 or the environment in the synthesis chamber. 1, the catalyst metal layer 110 is a single layer, and the graphene 120 is formed on both surfaces of the catalyst metal layer 110. However, the present invention is not limited thereto. That is, one layer of the multilayer substrate made of a plurality of layers may be the catalytic metal layer 110, and the graphene 120 may be formed only on one side of the catalytic metal layer 110 exposed.

Referring to FIG. 3, in step S20 of FIG. 1, the carrier 130 may be attached to the graphene 120 to form the first structure 10.

The carrier 130 may facilitate the handling of the graphene 120 until the process of transferring the graphene 120 to the target substrate 140 by supporting the graphene 120. When the graphenes 120 are synthesized on both surfaces of the catalytic metal layer 110, the carrier 130 can be formed on one surface of the graphene 120 to be transferred.

According to one embodiment, the carrier 130 may be a thermal release tape (TRT). The heat peeling tape (TRT) has adhesiveness at one side thereof at room temperature, but has a property of losing its adhesiveness when it is heated to a predetermined peeling temperature or higher, so that a product having various peeling temperatures can be selected.

According to another embodiment, the carrier 130 may be a polymer coating film. In this case, the carrier 130 may be formed by drop coating a liquid polymer on the graphene 120 and then curing it.

Examples of the polymer include polymethylmethacrylate (PMMA), polyamide (PA), polybutylene terephthalate (PBT), polycarbonate (PC), polyethylene (PE) ), Poly (oxymethylene) (POM), polypropylene (PP), poly (phenylenether): PPE, polystyrene (PS), polysulfone (LCP), polyetheretherketone (PEEK), polyetherimide (PEI), polylactide (PLA), and poly (dimethylsiloxane) dimethylsiloxane (PDMS) and cycloolefin copolymer (COC) may be used.

However, the carrier 130 is not limited thereto. For example, the carrier 130 may be composed of a variety of materials such as silicone and acrylic, as well as a heat peeling tape or polymer coating film, as long as it is used to transfer the graphene 120 to the target substrate 140.

Referring to FIG. 4, in step S30 of FIG. 1, the second structure 30 may be formed by removing the catalyst metal layer 110. Referring to FIG.

The catalytic metal layer 110 may be removed by an etching process. According to one embodiment, the etchant used in the etching process is acid, peroxide sulfuric acid based, hydrogen fluoride (HF), (Buffered Oxide etch ) BOE, iron chloride (FeCl _3), iron nitrate _{(Fe (No 3) 3)} , Copper sulfate (CuCl ₂ ), ammonium persulfate ((NH ₄ ) ₂ S ₂ O ₈ ) or sodium thiosulfate (Na ₂ S ₂ O ₈ ) solution may be used.

The etchant may be supplied to the catalyst metal layer 110 through any one of a spray-type, a bath-type, and a combination thereof. In the case of the spray type, the etchant is injected and supplied to the catalyst metal layer 110, and the catalyst metal layer 110 can be removed with a small amount of the etchant. In the case of the bath type, the etchant is filled in the water tank, and the catalytic metal layer 110 is immersed in the etchant to remove the etchant. Although a larger amount of etchant than the spray type is required, the etchant can be etched by contacting the entirety of the catalyst metal layer 110 .

After the etching process, a cleaning and drying process may be performed on the second structure 20. [ The etchant that may remain in the graphene 120 may be removed by a cleaning and drying process.

The width of the target substrate 140 may be 500 mm or more. The length of the target substrate 140 may be the same as the length of the graphene 120 transferred to the target substrate 140. When the width of the graphene 120 is less than 500 mm, It may be difficult to apply it to a transparent electrode of a touch panel included in a display device. For application in mass production, the graphene width should be at least 500 mm.

Referring to FIG. 5, in step S40 of FIG. 1, the surface of the target substrate 140 may be plasma-treated.

The target substrate 140 may be formed of polyethylene terephthalate (PET) or glass as the substrate to which the graphene 120 is to be transferred. However, the present invention is not limited thereto, and the target substrate 140 may be various kinds of transparent insulating substrates.

The plasma treatment is performed using argon (Ar) and oxygen (O ₂ ), and the flow ratio of oxygen (O ₂ ) to argon (Ar) is 0.1 to 0.5. The plasma processing can be performed at atmospheric pressure using radio frequency (RF). In the plasma processing, the applied power may be proportional to the length of the electrode, and the length of the electrode must be equal to or greater than the length of the target substrate 140 in order to uniformly perform plasma processing on the entire surface of the target substrate 140.

As described above, since the width of the target substrate 140 may be 500 mm or more, the length of the electrode may be 500 mm or more, and the applied power may be 375 W or more.

Hereinafter, optimum plasma processing conditions will be described with reference to Tables 1 to 4.

Table 1 shows the rate of change in sheet resistance measured while varying the flow ratio of oxygen (O ₂ ) to argon (Ar). The sheet resistance change ratio? R is a rate of change in sheet resistance after 120 hours under high temperature and high humidity conditions at a temperature of 85 deg. C and a humidity of 85% with respect to the sheet resistance immediately after transferring the graphene 120 to the target substrate 140 As a percentage.

When the length of the plasma electrode is 800 mm and the applied power is 800 W, the rate of change is negative when the oxygen flow rate is 0.1 to 0.5. This means that the sheet resistance is rather increased under high temperature and high humidity. It can be seen that the rate of sheet resistance change sharply increases when the oxygen flow ratio is 0.05, as compared with the case where the oxygen flow ratio is 0.1.

When the oxygen flow rate is 0.5 or more, plasma is not generated due to unstable discharge, and plasma processing can not be performed on the target substrate 140.

When the power applied to the same length of the plasma electrode is 640 W, the rate of change is negative when the oxygen flow rate is 0.1 to 0.5, as in the case of 800 W of power. However, it can be seen that the sheet resistance reduction rate is reduced compared to the case of 800 W of power. It can be seen that the sheet resistance is increased when the applied power is 540 W.

That is, according to one embodiment, when the length of the plasma electrode is 800 mm, the power applied is about 600 W or more, and the oxygen flow rate is 0.1 to 0.5, the sheet resistance of the graphene can be remarkably reduced after high temperature and high humidity.

Table 2 shows the rate of sheet resistance change (? R) when plasma treatment was performed at normal pressure using a medium frequency (MF). Nitrogen (N ₂ ), oxygen (O ₂ ) or nitrogen (N ₂ ) and carbon tetrafluoride (CF ₄ ) were used as a carrier gas and a voltage of 13 kV or 6 kV was applied.

According to Table 2, the sheet resistance after the high temperature and high humidity was greatly increased compared to the sheet resistance immediately after the transfer, and the rate of sheet resistance increase was larger than that without the plasma treatment.

Table 3 shows the adhesive force and the rate of change of sheet resistance (? R) when plasma treatment is performed in a vacuum using a radio frequency (RF). Oxygen (O ₂₎ and carbon tetrafluoride (CF _4), argon (Ar) and oxygen (O _2), nitrogen (N ₂₎ and hydrogen (H _2), oxygen (O ₂₎ and carbon tetrafluoride (CF ₄₎ or propane (C ₃ H ₈ ) was used as a carrier gas, and a power of 3 kW was applied.

According to Table 3, the sheet resistance after the high temperature and high humidity was increased compared to the sheet resistance immediately after the transfer, and the sheet resistance increase rate was decreased compared with the case without the plasma treatment, but the increase rate was not large. In addition, the recurrence rate was not good as a result of repetitive experiments with a decrease in the sheet resistance increase rate.

In some conditions of the vacuum plasma treatment, the adhesion between the target substrate 140 and the graphene 120 was poor.

Referring to Table 1 to Table 3, when plasma treatment was performed using argon (Ar) and oxygen (O ₂ ) as a carrier gas at atmospheric pressure using a radio frequency (RF) It can be seen that the sheet resistance of the pin 120 is reduced and particularly when the power is about 800 W and the flow ratio of oxygen (O ₂ ) to argon (Ar) is 0.1 to 0.5, the sheet resistance of the graphene 120 It can be confirmed that it is remarkably decreased.

6 and 7, in step S50 of FIG. 1, the target substrate 140 and the graphene 120 of the second structure 20 are opposed to each other and pressed.

The pressing process may be performed by disposing the target substrate 140 facing the exposed surface of the graphene 120 of the second structure 20 and pressing the target substrate 140 at a predetermined pressure. According to one embodiment, the pressing process may be performed by a roller transfer method in which pressing is performed by a roller.

Referring to FIG. 8, in step S60 of FIG. 1, the carrier 130 is removed from the third structure 30 to complete the graphene transfer process.

When the carrier 130 is a heat peeling tape, a predetermined heat is applied to separate the graphene 120 and the heat peeling tape. When the carrier 130 is a polymer coating film, the polymer coating film may be removed with an organic solvent such as acetone. In the case of a carrier film of silicone or acrylic type, graphene 120 And the carrier film 130 can be separated from each other. 8 shows a laminated structure of the target substrate 140 / graphene 120 from which the carrier 130 is removed.

Finally, the doping process, the drying process, and the analysis process may be further performed on the laminated structure of FIG. The transferred graphene 120 can be used for a transparent display, a flexible display, a solar cell, a touch panel, and the like.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

110: catalyst metal layer
120: Graphene
130: Carrier
140: target substrate

Claims (6)

Synthesizing graphene on at least one side of the catalyst metal layer;
Attaching a carrier to the graphene to form a first structure;
Removing the catalyst metal layer from the first structure to form a second structure;
Subjecting the target substrate to a plasma treatment under a condition that a flow rate ratio of oxygen to argon is 0.1 to 0.5;
Forming a third structure by pressing the graphene of the second structure facing the target substrate and opposed to each other; And
And removing the carrier. delete The method according to claim 1,
Wherein the plasma processing is performed at atmospheric pressure using a radio frequency. The method according to claim 1,
Wherein the length of the target substrate is 500 mm or more. delete delete

Images