KR100642719B1 - Methode for manufacturing carbon nano patterns and carbon nano patterns prepared by the same - Google Patents

Abstract

The present invention provides a method of forming a carbon nano pattern by carbonizing the polymer by spin coating a polymer film and then irradiating a predetermined amount or more of an electron beam.

According to the present invention, since a carbon nanopattern can be obtained by a very simple process, a patterned conductive or semiconductive film can be easily manufactured in a highly integrated device, and the thickness of the pattern can be freely controlled. The field is very wide.

Carbon nano pattern

Description

Method for manufacturing carbon nano patterns and carbon nano patterns prepared by the same}

1 is a schematic diagram illustrating a change occurring when an electron beam is irradiated to a polymer film.

2 is a derivative of the Auger electron spectrum for diamond, graphite and amorphous carbon.

FIG. 3 is Raman spectra for diamond, carbon nanotubes, fullerene (C ₆₀ ), amorphous carbon and graphite.

4 is a scanning electron microscope (SEM) photograph of the carbon nano pattern prepared according to Example 1. FIG.

FIG. 5 is an atomic force microscope (AFM) photograph of a carbon nano pattern prepared according to Example 1. FIG.

6 is an Auger electron spectrum for the carbon nano pattern prepared by Example 2. FIG.

FIG. 7 is an Auger electron spectrum for the carbon nanopattern prepared in Example 3. FIG.

8 is an AES depth profile for the carbon nano pattern prepared by Example 2. FIG.

9 is an AES depth profile for the carbon nano pattern prepared by Example 3. FIG.

FIG. 10 is a Raman spectrum for the carbon nano pattern prepared by Example 2. FIG.

FIG. 11 is a Raman spectrum for the carbon nano pattern prepared by Example 3. FIG.

12 is a result of measuring the electrical properties of the carbon nano pattern prepared in Example 2.

13 is a result of measuring the electrical properties of the carbon nano pattern prepared in Example 3.

The present invention relates to a carbon nanopattern, and more particularly, to a method for producing a carbon nanopattern in a desired form through a very simple process, and to a carbon nanopattern produced thereby.

Carbon materials can be divided into diamond, graphite, and amorphous carbon, which are not electrically conductive because the carbon atoms are connected by SP ³ bonds, but the graphite is electrically conductive because the carbon atoms are SP ² bonds. Is excellent, and in the case of amorphous carbon, the SP ³ bond and the SP ² bond are mixed, so the electrical conductivity is very low.

On the other hand, in recent years, in the case of carbon nanotubes, which have been studied as an electronic material material, the graphite layer is rounded, and has a diameter of several nm to several tens nm and a length of several tens to several hundred μm. It has the shape of various structures in the form of single wall, multi wall or rope. These carbon nanotubes have the properties of conductors or semiconductors depending on the shape of the coil (chirality), and the carbon nanotube powder is a mixture of semiconducting carbon nanotubes and metallic carbon nanotubes. When the metal is a zig-zag structure, it is semiconducting.

As a method of arranging such carbon nanotubes on a substrate, a method of arranging carbon nanotubes with sulfur by arranging the ends of carbon nanotubes on gold has been reported by Zhongfan Liu et al. Of Beijing University of China (Langmuir (2000)). 16: 3569). Other lithographic techniques include Chemical Physics Letters 303, p. 125 (1999), after forming a self-assembled monolayer of trimethylsilyl groups on a silicon substrate, patterning using an electron beam and adsorbing an amine group to the pattern, and then again carbon There is an example of adsorbing nanotubes. However, such a prior art has a problem that the process is not only very complicated but also the carbon nanotubes are simply adsorbed on the surface of the substrate, so that the bonding strength to the surface of the substrate is weak and the pattern formed is unstable.

On the other hand, Korean Patent Laid-Open Publication No. 2004-36526 discloses an amino group on a surface of a substrate, and then treated with an aminoalkyl carboxylic acid to form an amide bond between the amino group and the carboxyl group, and then apply a photoacid emitter and pattern After irradiating ultraviolet rays through the formed photomask and developing with an alkaline developer to form a positive pattern with a reactive amino group exposed on the surface, the substrate was finally reacted with carboxylated carbon nanotubes in the presence of a coupling agent. To form a carbon nanotube pattern. In this case, there is an advantage that the bonding strength is excellent because there is an amide bond between the surface of the substrate and the carbon nanotubes, but the density and uniformity of the carbon nanotubes are poor, it is difficult to control the thickness of the pattern, and the manufacturing process The disadvantage is that it is too complicated.

In addition, Korean Patent Laid-Open Publication No. 2004-43638 introduces a functional group having a double bond that can participate in radical polymerization on the surface of carbon nanotubes, and the carbon nanotubes are dispersed in an organic solvent with a photoinitiator and coated on a substrate. Thereafter, a method of forming a negative pattern of carbon nanotubes by exposure to ultraviolet rays through a photomask to cause radical polymerization of carbon nanotubes in the exposed portion and then removing the non-exposed portion with a developer is disclosed. The process is complicated because there is a step of introducing photocurable functional groups into the nanotubes, and electrical conductivity is achieved between the individual carbon nanotubes in the pattern prepared by the above method because acrylates and the like exist in the cured state of the photocurable functional groups. There is a risk of becoming poor, and the problem that the thickness of the pattern is not easy to control have.

The first technical problem to be achieved by the present invention is to provide a method of manufacturing a carbon nanopattern having a very simple process and free thickness control in order to solve the problems of the prior art.

The second technical problem to be achieved by the present invention is to provide a carbon nano pattern produced by the manufacturing method.

The present invention to achieve the first technical problem,

(a) forming a film by depositing a polymer or a low molecular organic compound on a silicon substrate, a glass substrate, or a plastic substrate;

(b) irradiating an electron beam to the deposited film surface to carbonize it; And

(c) it provides a method for producing a carbon nano pattern comprising the step of removing the non-irradiation of the electron beam of the film.

According to one embodiment of the present invention, the high molecular organic compound of step (a) may be polymethyl acrylate, polymethyl methacrylate, polystyrene, polyfluorene, novolac, polyester or polyurethane.

In addition, the low molecular weight organic compound of step (a) may be an organic compound containing two or more aromatic rings.

According to another embodiment of the present invention, the irradiation amount of the electron beam of step (b) may be 1 to 20 mC / cm ² .

According to another embodiment of the present invention, the resistance of the carbon nano pattern is preferably 10 ⁻² (Ω · m) or less.

The present invention provides a carbon nano pattern, characterized in that produced by the manufacturing method according to the present invention in order to achieve the second technical problem.

Hereinafter, the present invention will be described in more detail.

Method for producing a carbon nano pattern according to the present invention comprises the steps of (a) forming a film by forming a polymer or a low molecular organic compound on a silicon substrate, a glass substrate or a plastic substrate; (b) irradiating an electron beam on the film surface formed Carbonizing; And (c) it is characterized in that it comprises the step of removing the non-irradiation of the electron beam of the film, the manufacturing process of the carbon nanopattern is very simple, there is an advantage that the width and thickness of the pattern can be freely adjusted in nano units.

Referring to FIG. 1, after forming a polymethylmethacrylate coating film on a silicon substrate according to the present invention, for example, irradiating an electron beam of μC / cm ² according to a predetermined pattern shape, FIG. As shown, the bonds in the polymer are broken due to the high energy of the electron beam, and are changed into chemical species as shown in FIG. If the irradiation amount of the electron beam increases, atoms such as oxygen and hydrogen, except carbon, of the chemical species are completely vaporized, and only carbon remains on the substrate, which is developed using an organic solvent such as methyl isobutyl ketone. In this case, only the carbonized portion and the portion not irradiated with the electron beam remain on the substrate, and the size or shape of the carbon nano pattern thus formed can be confirmed through the scanning electron microscope. Subsequently, using a release agent such as acetone completely removes the coating film on the unexposed portion, leaving only the desired carbon nano pattern.

At this time, whether the structure of the remaining carbon is graphite or amorphous carbon is a problem, Figure 2 shows the differential value of the Auger Electron Spectrum (Aug) in the order of diamond, graphite and amorphous carbon. FIG. 2 (a) is a spectrum for diamond, with two peaks at 246eV and 255eV, one at 248eV or 249eV for the graphite and amorphous carbon shown in FIGS. 2 (b) and 2 (c). The peak of is shown, and therefore, it can be seen that the spectrum of graphite and the spectrum of amorphous carbon are similar to each other. However, in the case of the amorphous carbon shown in Fig. 2 (c), there is a slight shoulder on the right side of the spectrum shown in 271eV can be distinguished. Taking the AES of the carbon nanopattern prepared according to the present invention, it can be distinguished from graphite form or amorphous carbon form.

In addition, Figure 3 shows the Raman spectrum for diamond, carbon nanotubes, fullerene (fullerene (C ₆₀ )), amorphous carbon and graphite. Referring to FIG. 3, in the case of graphite, there is one peak at 1582 cm ⁻¹ , which means that carbon has an SP ² bond, hereinafter referred to as G mode. In contrast, in the case of amorphous carbon, in addition to the G mode, there is another major peak at 1350 cm ⁻¹ , which means that the carbon has an SP ³ bond, hereinafter referred to as D mode. That is, by taking a Raman spectrum of the carbon nanopattern prepared according to the present invention and analyzing it, it may be distinguished from graphite or amorphous carbon form.

Of course, the simplest method is to measure the electrical conductivity of the carbon nanopatterns prepared according to the present invention. That is, in the case of amorphous carbon, the resistance is about 0.35 (Ω · m), and the electrical conductivity is very low. In the case of graphite, the resistance is about 6.5 × 10 ⁻⁷ (Ω · m), which is excellent. By measuring the electrical conductivity of the carbon nanopattern prepared according to the invention, it can be confirmed whether the form is graphite or amorphous carbon.

The high molecular organic compound that can be used in step (a) is not particularly limited, but it is preferable that the repeating unit contains an aromatic ring such as benzene, naphthalene, anthracene, pyrene, fluorene, carbazole ring, and the like. This is because the formation of a carbon pattern of a desired density is easy. However, when intentionally preparing a thin pattern, the repeating unit may not have an aromatic ring. Examples of the polymer include polymethyl acrylate, polymethyl methacrylate, polystyrene, polyfluorene, novolac, polyester or polyurethane, and all of them can be used without distinguishing the additive polymer and the condensation polymer. .

On the other hand, the low-molecular organic compound that can be used in step (a) is not particularly limited as long as it can be produced in the form of a film, for example, it may be an organic compound in a solid form at room temperature by including two or more aromatic rings.

Dose of the electron beam of step (c) used in the present invention may be a 1 to 20 mC / cm ^2, the strength of the electron beam does not occur when less than 1mC / cm ² of the organic compound sufficient carbon painter, 20mC / cm When it exceeds ² , scattering occurs when atoms of the chemical species in the coating film collide with electrons of the electron beam, and thus the electron beam affects a wider area than the desired part, and the surrounding organic compound may also be carbonized. As a result, there is a problem that a pattern having a width thicker than the desired width is obtained.

On the other hand, the resistance of the carbon nanopattern obtained in the present invention is preferably 10 ^-2 (Ωm) or less, in the case where the electrical conductivity should be large, it is necessary to complete the graphitization, but the electrical conductivity does not need to be large May also produce a pattern in which the graphitization is not complete.

The present invention provides a carbon nano pattern, characterized in that produced by the manufacturing method according to the present invention in order to achieve the second technical problem.

Hereinafter, the present invention will be described in more detail with reference to preferred examples, but the present invention is not limited thereto.

Example 1

Polymethyl methacrylate was dissolved in cyclohexanone to prepare a polymer solution of 2% by weight, and then spin-coated on a silicon substrate, where the dry thickness of the coating film was 25 nm. Next, the substrate was placed in an electron scanning microscope equipped with an electron beam irradiation apparatus (manufactured by Raith), vacuumed with an ion pump, and irradiated with an electron beam in a pattern form in an amount of ⁴ mC / cm ² , followed by methyl isobutyl ketone The carbon nanopattern was obtained by developing using using as a developing solution. FIG. 4 (a) shows an electron scanning microscope (SEM) photograph after developing with methyl isobutyl ketone after irradiation with an electron beam, and FIG. 4 (b) is not irradiated with acetone as a release agent. After all the parts were peeled off, electron scanning micrographs of the remaining carbon nanopatterns were shown. Referring to FIG. 4 (a), the carbon nato pattern is formed in a straight line, and an elliptical bright part is shown at the periphery thereof, which is affected by the polymer film other than the desired part by the scattering of the electron beam. Therefore, it corresponds to the part developed by the developing solution. As described above, the larger the irradiation amount of the electron beam, the larger the size of the elliptical portion, and thus, the width of the pattern is wider than intended. On the other hand, referring to Figure 4 (b), after the treatment with the release agent it can be seen that all the polymer film is removed and only the pattern of the desired width is formed. On the other hand, Figure 5 shows an atomic force microscope (AFM) picture of the carbon nano pattern prepared in this embodiment, it can be seen that the carbon nano pattern is formed with a certain thickness.

Example 2

A carbon nano pattern was manufactured in the same manner as in Example 1, except that the irradiation amount of the electron beam was 7 mC / cm ² .

Example 3

Carbon nanopatterns were prepared in the same manner as in Example 2, except that polystyrene was used instead of polymethylmethacrylate.

Test Example 1

AES experiment

AES was obtained for the carbon nanopatterns prepared in Examples 2 and 3, and the results are shown in FIGS. 6 and 7. 6 and 7, polymethyl methacrylate and polystyrene have almost the same shape of the spectrum, and it can be confirmed that the graphite structure has been found that almost no shoulder is shown on the right side of the 280 eV spectrum. 8 and 9 illustrate AES depth profiles of the carbon nanopatterns prepared in Examples 3 and 3, respectively. Referring to this, it can be seen that the surface of the substrate is present in 90% or more carbon, but also about 5% Si. This is thought to be the diffusion of Si atoms present in the substrate into the carbon nanopattern by the electron beam.

Test Example 2

Raman Experiment

The Raman (JOBIN YVON T64000, France) spectrum of the carbon nanopatterns prepared by Examples 2 and 3 was measured and shown in FIGS. 10 and 11. Even when 10 and 11, which may be referred to as G-mode, because at about 1600cm ^-1 peak to appear, may be near 1350 cm ^-1, the peak is nearly no. Therefore, it can be seen that the carbon nano pattern formed is composed of a graphite structure mainly consisting of SP ² bonds.

Test Example 3

Electrical characteristic experiment

After the electrical properties of the carbon nanopatterns prepared in Examples 2 and 3 were measured, the results are shown in FIGS. 12 and 13. In the measurement, a gold electrode was formed on a silicon substrate, and the current and voltage characteristics between the two electrodes were measured using a silicon substrate having a carbon nano pattern prepared in Example as the other electrode. Looking at the electrical properties it can be seen that the carbon nanopattern prepared in the embodiment is not a diamond structure or an amorphous carbon structure but a graphite structure.

As described above, the carbon nanopattern manufacturing method according to the present invention can obtain a carbon nanopattern by a very simple process, it is possible to easily produce a patterned carbon nanopattern on a highly integrated device, the pattern Since the thickness of the metal is also free to control, its application is very wide.

Claims (6)

(a) forming a film by depositing a polymer or a low molecular organic compound on a silicon substrate, a glass substrate, or a plastic substrate; (b) irradiating an electron beam to the deposited film surface to carbonize it; And (c) removing the electron beam non-irradiation portion of the film; [Claim 2] The carbon nano pattern of claim 1, wherein the polymer organic compound of step (a) is polymethyl acrylate, polymethyl methacrylate, polystyrene, polyfluorene, novolac, polyester or polyurethane. Manufacturing method. The method of claim 1, wherein the low molecular weight organic compound of step (a) is an organic compound comprising two or more aromatic rings. The method of claim 1, wherein the irradiation amount of the electron beam of step (c) is 1 to 20 mC / cm ² method for producing a carbon nano pattern. The method of claim 1, wherein the resistance of the carbon nanopattern is 10 ⁻² (Ω · m) or less. Carbon nano pattern produced by the method according to any one of claims 1 to 5.

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