KR100809602B1 - Method for etching of insulating layers using carbon nanotubes and formation of nanostructures thereafter - Google Patents

Abstract

A method for etching insulating layers using carbon nano tubes and nano structures manufactured by the same are provided to fabricate a nano trench having a width of 0.5 to 500 nm by using the carbon nano tube whose diameter is 0.5 to 300 nm. An insulating layer is formed on an upper portion of a substrate. A carbon nano tube is formed on an upper portion of the insulating layer. A nano trench is formed in the insulating layer by using a carbothermal reduction reaction of the insulating layer on which the carbon nano tube is formed. The substrate is selected from a group consisting of a silicon wafer, sapphire, glass, quartz, metal, alumina, and plastic. The insulating layer is made of a compound containing silicon. The carbon nano tube is formed by a method selected from a group consisting of CVD(Chemical Vapor Deposition), laser ablation, arc-discharge, PECVD(Plasma Enhanced Chemical Vapor Deposition), vapor phase growth, sonication method, electrolysis, and flame synthesis.

Description

Method for etching of insulating layers using carbon nanotubes and formation of nanostructures thereafter}

FIG. 1A is a schematic diagram of a process of forming a nano trench induced by carbon nanotubes during an oxygen-implanted chemical vapor deposition reaction.

FIG. 1B shows a tapping mode atomic force microscopy (AFM) photograph of a SiO ₂ / Si substrate with linear nano trenches.

FIG. 1C shows a tapping mode atomic force micrograph of a SiO ₂ / Si substrate with a portion of unreacted carbon nanotubes remaining at the ends of the nanotrench.

2A is a schematic diagram of a process for forming Cr nanowires (left) and Si nano trenches (right) using SiO ₂ nano trenches as a mask.

2B-2E show low and high magnification atomic force micrographs of Cr nanowires.

2F and 2G show low and high magnification atomic force micrographs of Si nano trenches.

The present invention relates to an etching method of an insulating layer using carbon nanotubes and a nanostructure manufactured by using the same, more specifically, simpler, more environmentally friendly, and an insulating having an average width of 0.5 to 500 nm compared to conventional methods. A method of etching an insulating layer using carbon nanotubes and a nano-manufactured using the same, which can manufacture a nano trench of a layer, and can provide a nanostructure for a high density integrated device using the nano trench of the insulating layer as a mask. It is about a structure.

Due to the rapid development of semiconductor manufacturing technology and the integration of various electronic component devices, efforts to implement more circuits and devices in a smaller chip area are being accelerated. As the size of semiconductor devices decreases, the line width of the corresponding devices is also slightly reduced, and the importance of the structure of the nado unit, such as the nanowires constituting the devices and the nano trenches of the semiconductor substrate, is also increasing day by day.

Since these nanostructures are very small in size, they cannot be manufactured through a general photolithography process because of the limitations of the exposure equipment used in the exposure process. In other words, it is impossible to realize a line width below the wavelength of the light source due to the diffraction limit of light, so it is impossible to realize a nano size line width.

However, even when using an exposure method, there is a technology that can implement a nano-pattern, such as electron beam lithography (E-Beam Lithography). The electron beam lithography uses a method of drawing a pattern as if it is drawing with a fine brush by using an electron beam, thereby realizing a line width of about tens of nanometers, which was impossible with conventional exposure techniques. However, since the line width of nanostructures possible by electron beam lithography has a limit of several tens of nanometers, it is difficult to cope with the recent technology that is gradually getting smaller, and because the process speed is very slow and the equipment is expensive, electron beam lithography for the purpose of manufacturing nanostructures Using is not economical.

In addition, the method of manufacturing a nano-sized structure by the conventional printing method has a number of problems, such as a constraint on its shape.

Carbon nanotubes, on the other hand, are arranged in a hexagonal honeycomb pattern of carbon atoms in the form of a tube, the diameter of the tube is a very small nanometer material. Single-walled carbon nanotubes (SWNT), double-walled carbon nanotubes (DWNT), and multi-walled carbon nanotubes (MWNT) depending on the number of bonds of graphite And rope carbon nanotubes. Nippon Electric Company in 1991, when Kroto and Smalley first discovered Fullerene (a collection of 60 carbon atoms: C ₆₀ ), one of the allotrope of carbon. Dr. Iijima of the (NEC) research institute has a long, long, carbon-like carbon nanotube that analyzes the mass of carbon formed on the graphite cathode by using an arc-discharge method with a transmission electron microscope (TEM). The tube was found and published for the first time in Nature. Carbon nanotubes can be used for electro-discharge, laser ablation, plasma enhanced chemical vapor deposition, chemical vapor deposition, vapor phase growth, It can be mass-produced by electrolysis, flame synthesis, or the like. In addition, the carbon nanotubes have excellent mechanical properties, electrical selectivity, excellent field emission characteristics, high efficiency hydrogen storage medium characteristics, and thus have a wide application range.

Thus, research and application of the chemical reactivity of carbon nanotubes has led to the successful implementation of nanoelectronics, composites, gas storages, energy conversion systems, sensitive chemicals, and biochemical sensors. It can be a decisive and fundamental solution. To date, most of the research on the chemical reaction of carbon nanotubes has focused on surface tethering with organic functional molecules through non-covalent or covalent coupling reactions. In contrast, the chemical reactions of carbon nanotubes with complete combustion of the carbon constituting the carbon nanotubes have been little studied mainly due to their high chemical and thermal stability.

As such, the synthesis of nanoscale structures to meet the integration requirements of various electronic component devices is continuously required. To solve this problem, devices having an etching state of 10 nm or less having carbon nanotubes or similar external features are solved. Alternatively, a technology for manufacturing nanowires is currently required.

The technical problem to be achieved by the present invention is to provide a method for etching an insulating layer using carbon nanotubes, which are simpler, more environmentally friendly, and capable of producing nano-trenches having a width of 0.5 to 500 nm, compared to the existing methods.

Another technical problem to be achieved by the present invention is to provide a nanostructure manufactured using the above method.

The present invention to achieve the above technical problem,

Forming an insulating layer on the substrate;

Forming carbon nanotubes on the insulating layer; And

Provided is an etching method of an insulating layer using carbon nanotubes, including forming a nano trench in the insulating layer by a carbon thermal reduction reaction of the insulating layer on which the carbon nanotubes are formed.

In the etching method of the insulating layer according to an embodiment of the present invention, the substrate may be selected from the group consisting of silicon wafer, sapphire, glass, quartz, metal, alumina, and plastic.

In the etching method of the insulating layer according to an embodiment of the present invention, the insulating layer may be formed of a compound containing silicon.

In the etching method of the insulating layer according to an embodiment of the present invention, the insulating layer may be formed of one or more selected from the group consisting of silicon oxide, silicon dioxide, silicon nitrate, and silicon nitride.

In the etching method of the insulating layer according to an embodiment of the present invention, the carbon nanotubes are chemical vapor deposition (CVD), laser ablation, (arc-discharge), Plasma Enhanced Chemical Vapor Deposition (PECVD), vapor phase growth, sonication method, electrolysis and flame synthesis It can be formed by.

In the etching method of the insulating layer according to an embodiment of the present invention, the carbon nanotubes are single-walled carbon nanotubes (SWNT), double-walled carbon nanotubes (DWNT), Multi-walled carbon nanotubes (MWNT), bundle carbon nanotubes (rope carbon nanotube) and the catalyst may be selected from the group consisting of a structure surrounding the carbon particles.

In the etching method of the insulating layer according to an embodiment of the present invention, the carbon nanotubes may have an average diameter of 0.5 to 300 nm.

In the etching method of the insulating layer according to an embodiment of the present invention, the carbon melt reduction reaction may be made while injecting oxygen and inert gas.

In addition, the oxygen content may be 0.0001 to 30% of the total gas volume.

In the etching method of the insulating layer according to an embodiment of the present invention, the carbon melt reduction reaction may be performed at a temperature of 700 to 1200 ℃.

In the etching method of the insulating layer according to an embodiment of the present invention, the nano trench of the insulating layer may have an average width of 0.5 to 500 nm.

In the etching method of the insulating layer according to an embodiment of the present invention, the forming step of the carbon nanotubes and the carbon melt reduction reaction (carbothermal reduction) may occur at the same time.

In addition, the forming of the carbon nanotubes and the carbonthermal reduction reaction may occur while simultaneously injecting oxygen, hydrogen, and hydrocarbons.

In addition, the oxygen content may be 0.01 to 2% of the total gas volume.

In addition, the hydrocarbon may be one or more selected from the group consisting of methane, ethane, acetylene, ethylene, butane, propane.

In the etching method of the insulating layer according to an embodiment of the present invention, the upper portion of the substrate on which the insulating layer is formed may be deposited with a metal or transition metal catalyst.

In addition, the metal or transition metal catalyst is nickel (Ni), iron (Fe), cobalt (Co), yttrium (Y), molybdenum (Mo), aluminum (Al), rhodium (Rh), palladium (Pd) , Gold (Au), silver (Ag), copper (Cu) or an alloy thereof.

The present invention to achieve the above other technical problem,

It provides a nanostructure manufactured by using the etching method of the insulating layer.

In the nanostructure according to the embodiment of the present invention, the nanostructure may be an array of metal / semiconductor nanowires, an etch structure of a semiconductor substrate, or metal / semiconductor nanoparticles.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

As described above, the etching method of the insulating layer using carbon nanotubes, which is an aspect of the present invention,

Forming an insulating layer on the substrate;

Forming carbon nanotubes on the insulating layer; And

And forming a nano trench in the insulating layer by a carbon thermal reduction reaction of the insulating layer on which the carbon nanotubes are formed.

First, the step of forming the insulating layer on the substrate will be described in detail.

The substrate is not particularly limited, and specific examples thereof include silicon wafers, sapphire, glass, quartz, metals, alumina, plastics, and the like.

The insulating layer is not particularly limited as long as it is a compound containing silicon, but may be formed of at least one selected from the group consisting of silicon oxide, silicon dioxide, silicon nitride, and silicon nitride. In this case, when the insulating layer is made of silicon dioxide, it is more preferable because of the high efficiency of forming the nano trench due to the carbon melt reduction reaction.

As an example of the insulating layer, the insulating layer made of silicon dioxide (SiO ₂ ) may be formed by an oxidation method using dry oxygen or water vapor, which is conventionally used for the silicon wafer as the substrate, and the thickness thereof is not particularly limited. In the laboratory, SiO ₂ can be formed by firing a silicon wafer at 800 to 1200 ° C. in air for several seconds to several ten minutes. The SiO ₂ layers are formed by chemical oxidation of a silicon wafer, and the thickness thereof can be confirmed by using an ellipsometer. The present invention is applied regardless of the thickness as long as the SiO ₂ layers are present, and the thickness of the SiO ₂ layers may be determined according to the purpose of use.

Thereafter, after forming an insulating layer on the substrate, and before forming carbon nanotubes, the upper portion of the substrate may be deposited with a metal or a transition metal catalyst. The metal or transition metal catalyst is nickel (Ni), iron (Fe), cobalt (Co), yttrium (Y), molybdenum (Mo), aluminum (Al), rhodium (Rh), palladium (Pd), gold Single metal or transition metal such as (Au), silver (Ag), copper (Cu), or cobalt (Co) -nickel (Ni), cobalt (Co) -iron (Fe), nickel (Ni) -iron (Fe) ), Cobalt (Co) -nickel (Ni) -iron (Fe) and the like or also made of two or three kinds of alloys.

The metal or transition metal catalyst may have a thickness of several tens to tens of thousands on the substrate by using thermal evaporation, sputtering, electron beam evaporation, or a reaction between chemicals in an aqueous solution. Form metal or transition metal nanoparticles.

Thereafter, the carbon nanotubes are selected from the group consisting of chemical vapor deposition, laser ablation, electrodischarge, plasma enhanced chemical vapor deposition, vapor phase synthesis, ultrasonic synthesis, electrolysis, and flame synthesis on the substrate on which the insulating layer is formed. It can be formed by the method. At this time, chemical vapor deposition (CVD) and plasma enhanced chemical vapor deposition (PECVD) are more preferable because they have a high efficiency of nanotrench formation by the direct reaction of the catalyst particles with the substrate.

In one embodiment of the present invention, the carbon nanotubes may be selected from the group consisting of single-walled nanotubes, double-walled nanotubes, multi-walled nanotubes, bundle-type nanotubes and a structure surrounding the catalyst with carbon particles.

 In the present invention, since the nano trench formed in the insulating layer is completely guided by the carbon nanotubes, the characteristics of the nano trenches of the insulating layer are determined according to the trajectory, length and width of the carbon nanotubes. Therefore, the carbon nanotubes according to the exemplary embodiment of the present invention more preferably have an average diameter of 0.5 to 300 nm in relation to the width of the nano trenches to be formed.

Next, the step of forming the nano trench in the insulating layer on which the carbon nanotubes are formed will be described in detail.

The nano trench of the insulating layer is formed by a carbon thermal reduction reaction between the carbon nanotubes and the insulating layer formed on the substrate, the reaction is chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), It may be formed by a method selected from the group consisting of thermochemical vapor deposition, gas phase synthesis.

In this case, carbon (C) of the carbon nanotubes serves as a reducing agent to reduce and etch the insulating layer.

The carbon melt reduction reaction may be carried out at a temperature of 700 to 1200 ℃, preferably 800 to 950 ℃, if the reaction temperature is less than 700 ℃ to reduce the production efficiency of carbon nanotubes and nano trenches, exceeding 1200 ℃ In this case, there may be economic loss and gas explosion risk due to high temperature reaction.

Meanwhile, in one embodiment of the present invention, the carbon melt reduction reaction of the substrate on which the carbon nanotubes are formed may be performed while injecting oxygen and an inert gas. That is, when oxygen is included in the melt reduction reaction, breakage of carbon nanotubes having high crystallinity and thermal stability occurs more easily, and a locally defined reactive carbonaceous component reacting with the insulating layer at the same temperature is obtained. Create

The efficiency of the nanotrench formation is directly related to the amount of oxygen injected.

When the carbon nanotubes are formed on the insulating layer, induction of carbon melt reduction of the insulating layer may be performed while injecting oxygen and an inert gas. At this time, the content of oxygen is 0.0001 to 30%, preferably 0.0003 to 0.01% of the total gas volume.

When the oxygen content is less than 0.0001%, the carbon melting reduction reaction may not occur smoothly, and thus the efficiency of nano trench formation may be drastically reduced. When the oxygen content is more than 30%, the oxidation reaction of excess oxygen and carbon nanotubes itself is reduced. Because it occurs first, the efficiency of nanotrench formation can also be drastically reduced.

As the inert gas containing oxygen, helium, neon, argon, krypton, xenon, radon may be used, and argon may be preferably used.

In the etching method of the insulating layer according to an embodiment of the present invention, the carbon nanotube formation step and the carbon melt reduction reaction of the substrate on which the carbon nanotubes are formed may occur simultaneously. That is, when oxygen, hydrogen, and hydrocarbon gas are injected into a chemical vapor deposition system for forming carbon nanotubes on a substrate, the carbon nanotubes formed at the same time as the carbon nanotubes are formed on the insulating layer of the substrate serve as a reducing agent. The carbon melt reduction reaction of the insulating layer occurs. Therefore, there is an advantage that it is possible to form the nano trench of the insulating layer while reducing fuel loss in a short time.

That is, in the case where the carbon nanotube formation and the carbon melt reduction reaction are simultaneously performed, by providing carbon in addition to the amount of carbon provided only by the carbon nanotubes at the time of forming the nano trench, the efficiency of nano trench formation of the insulating layer Can be increased.

At this time, the content of oxygen is 0.01 to 2%, preferably 0.03 to 0.1% of the total gas volume. When the oxygen content is less than 0.01%, the carbon melt reduction reaction does not occur smoothly, and the efficiency of nano trench formation may be drastically reduced. When the oxygen content exceeds 2%, excess oxygen and hydrocarbon gas react to explode during the reaction. There is a risk. The content of hydrogen and hydrocarbon is not particularly limited, but the content of hydrogen is 20 to 50%, preferably 25 to 40%, and the content of hydrocarbon is 50 to 80%, preferably 55 to 75, relative to the total gas volume. %to be.

The hydrocarbon is not particularly limited, and specific examples thereof may be at least one selected from the group consisting of methane, ethane, acetylene, ethylene, butane, and propane. At this time, the use of methane, ethylene and acetylene may be more preferably used because it efficiently synthesizes nanotubes.

In addition, the nanoparticles of the metal or transition metal catalyst used in the formation of the carbon nanotubes also accelerate the thermal evaporation of the insulating layer, thereby increasing the conversion rate of the carbon nanotubes into the nano trenches in the efficient carbon melt reduction reaction of the insulating layer. Play a role.

That is, the dispersion of carbon nanotubes to remove the catalyst by acidic treatment in chloroform and the sonication to the number of the weight separation using a centrifugal separator iterations relatively light only SiO ₂ carbon nanotube solution to prevent aggregation between the nanotubes After dispersion through spin-coating, the reaction is induced by chemical vapor deposition, and the number of nano trenches formed is significantly reduced compared to the case where the catalyst is included.

In addition, in the case where amorphous carbon particles containing no catalyst are dispersed in the insulating layer through spin coating, carbon melting reduction reaction is induced, and fewer nano holes or trenches are generated in the insulating layer than when the catalyst is included. Could be observed.

This can be confirmed that the intrinsic properties of the metal or transition metal catalyst and the result of the carbon melt reduction reaction by the carbon structure of the graphite structure, nanotube or amorphous carbon film formed by reacting with the hydrocarbon.

For example, it is easy to observe that most of the nano trenches formed with holes or formed by etching where the catalyst was present also do not contain any catalyst at both ends. As the molecules form the film, they can be traced to their removal by the carbon melt reduction reaction or evaporated due to the low melting point due to the interaction between the catalyst and the insulating layer.

The morphological characteristics of the nano trenches of the insulating layer according to the invention are determined by the original characteristics of the carbon nanotubes, since the nano trenches are formed by a carbon melt reduction reaction between the insulating layers in contact with the carbon nanotubes. Therefore, the length of the nano trench may correspond to the length of the carbon nanotubes to extend to several tens of micrometers.

In addition, the average width of the nano trench can be measured using a cross-sectional high resolution transmission electron microscopy (HRTEM), the average width of the nano trench of the insulating layer is 0.5 to 500 nm.

Hereinafter, as an embodiment of the present invention, the step of forming the nano trench of the insulating layer using the case where the insulating layer is an SiO ₂ layer will be described.

As described above, the main driving force for forming the nano trenches of the SiO ₂ layer, which is the insulating layer, is a SiO ₂ carbon melting reduction reaction in which carbon nanotubes serve as a reducing agent. Amorphous bulk silica (SiO ₂ (s)) is known to be reduced by carbon (C (s)) at least 1000 ° C. and under atmospheric pressure by releasing SiO (g) and CO (g) as in the following formula: .

SiO ₂ (s) + C (s) ↔ SiO (g) + CO (g)

In the above formula, the carbon nanotubes serve as C (s) to thermally reduce SiO ₂ .

1A and 1B are schematic and atomic force micrographs (AFM) of the formation of nano trenches induced by carbon nanotubes during an oxygen-implanted chemical vapor deposition reaction. That is, carbon nanotube synthesis and carbon melting are performed by placing a substrate on which a catalyst is deposited in a chemical vapor deposition apparatus and simultaneously injecting oxygen, hydrogen, and hydrocarbon (methane or ethylene) gases at a temperature of 700 ° C. to 1200 ° C. Carbothermal reduction reactions occur.

Due to this reaction, the synthesis of carbon nanotubes proceeds, and the reduction of the surface of the substrate such as SiO ₂ occurs. As a result, a SiO ₂ layer is formed in which carbon nanotube sites are etched. The solid phase SiO ₂ and C must be in contact with each other in order for the reaction to occur, and only carbon nanotubes in direct contact with the SiO ₂ surface are activated for the reaction.

On the other hand, referring to 1c, when the reaction between the carbon nanotubes and SiO ₂ is incomplete, it can be seen that a portion of the unreacted carbon nanotubes remaining at the end of the formed nano trench. It can be seen that the carbon nanotubes play a role as a reducing agent in the reaction.

Another aspect of the present invention relates to a nanostructure manufactured by using the etching method of the insulating layer.

By using a nano-tren of the insulating layer prepared by using the etching method as a mask, it is possible to provide a nanostructure, such as metal / semiconductor nanowires, etching structures of a semiconductor substrate, or an array of metal / semiconductor nanoparticles. One of the important problems in the production of one-dimensional metal nanowires and nano-trenches of semiconductor substrates is to obtain nanostructures having a diameter or width smaller than 10 nm. There is an advantage to this.

Metal nanowires according to the present invention, using an insulating layer etched according to the above-described method as a mask, the metal is deposited thereon, and then the insulating layer used as the mask by immersing the metal-deposited substrate in a developing solution It is prepared by removing the.

At this time, as the metal used for the deposition, any one of Cr, GaAs, GaN, Ti, Pd, Ni, Co, Al, Ag, Pt, Au and Cu may be selected. The method for depositing the metal is not particularly limited and may be performed by a conventional method.

In addition, a method of dipping in a developing solution is used to remove the insulating layer after metal deposition, and any solution capable of dissolving the insulating layer may be used without limitation. For example, in the case of the silicon oxide insulating layer, an HF aqueous solution having a content of 0.1% or more is preferable.

As an example of the nanostructures according to the present invention, nanotren, which is an etch structure of a nanometer-scale Si substrate useful in nanoelectronic technology, may be prepared using the same SiO ₂ nanotrench mask.

That is, the Si substrate on which the SiO ₂ nano trench is formed is immersed in a KOH aqueous solution or the like to etch Si, and then immersed in an HF aqueous solution or the like to remove the SiO ₂ nano trench mask layer, thereby preparing a nano trench which is an etch structure of the Si substrate.

FIG. 2A schematically illustrates the process of forming Cr nanowires (left) and Si nano trenches (right) using SiO ₂ nano trenches as a mask, as described above.

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

Example

SiO ₂  Preparation of Nano Trench

To induce the etching of carbon nanotubes and SiO ₂ substrates, iron catalysts were first deposited on SiO ₂ / Si substrates. 100 μL of 40 mM NH ₂ OH.HCl aqueous solution and 10 μL of 10 mM FeCl ₃ .6H ₂ O aqueous solution were added to 10 mL of tertiary distilled water in which SiO ₂ / Si substrate was immersed using a micro pipette. After reacting for 3 minutes, an iron catalyst having a diameter size (average: 1.7 nm) of nanotubes was densely formed on the substrate. The substrate sample on which the iron catalyst was deposited was transferred into a quartz tube of a chemical vapor deposition (CVD) and then reduced to 500 sccm of H ₂ gas and heated up to about 830 ° C. When the temperature reached 830 ° C., the valves of the O ₂ / CH ₄ / C ₂ H ₄ gas were opened, with the amount of each gas (gas flow) being 1.5 / 1000/20 sccm. When the temperature reached 900 ° C, the reaction was further performed for about 10 minutes, the valve of O ₂ / CH ₄ / C ₂ H ₄ gas was closed, the temperature was lowered to room temperature, and the sample was taken out. This experiment induced the synthesis of carbon nanotubes and the melting reaction of carbon by using hydrogen, hydrocarbons, and oxygen. The resulting SiO ₂ / Si substrate having a well-refined linear nano trench is shown in FIG. 1B in a tapping mode atomic force microscopy (AFM) photograph.

The nano trenches of the SiO ₂ substrate may be formed by inducing a carbon melting reduction reaction on the carbon nanotube samples already formed. Synthesis of carbon nanotubes is the same as the above experimental method except for the injection of oxygen gas. Subsequently, the substrate on which the carbon nanotubes were synthesized was transferred back to the quartz tube of the chemical vapor deposition machine. After flowing 1000 sccm of Ar gas (containing 0.0001% of oxygen gas), the temperature was raised to 900 ° C. and reacted for at least 5 minutes at room temperature. When the temperature is lowered, it can be observed that the SiO ₂ nano trench is formed on the SiO ₂ / Si substrate by the carbon melting reduction reaction.

Preparation of Cr Nanowires

Cr nanowires according to the present invention were prepared by simple metal evaporation, using SiO ₂ nano trenches as masks. Prior to fabricating the Cr nanowires, the samples were fired in air at about 800 ° C. to remove one of the reaction products, organic matter and carbon nanotubes, and to create a clean SiO ₂ nanotrench surface. In order to remove the thin SiO ₂ layer formed in this process, the sample may be immersed in about 5% diluted HF aqueous solution for about 1 minute. Thermal deposition of Cr proceeds at target thicknesses of 4 and 8 nm, respectively, and then the Cr thermally deposited substrate is subjected to 1-3 in a diluted HF solution (H ₂ O: HF (50%) = 2: 1 volume ratio). The reaction was carried out for minutes to remove the SiO ₂ nanotren. As a result, Cr nanowires having a height of about 4.4 nm and 8.5 nm were produced. The resulting Cr nanowires are shown in the low and high magnification atomic force microscopy (AFM) images of FIGS. 2B-2E.

Preparation of Si Nano Trench

Si nano trenches according to the present invention were prepared by etching with an aqueous KOH solution, using SiO ₂ nano trenches as masks. Prior to fabricating the Si nano trenches, the samples were calcined in air at about 800 ° C. to remove one of the reaction products, organic material and carbon nanotubes, and to create a clean SiO ₂ nano trench surface. In order to remove the thin SiO ₂ layer formed in this process, the sample may be immersed in about 5% diluted HF aqueous solution for about 1 minute. Thereafter, the sample was immersed in an aqueous KOH solution having a 45% composition ratio of 83 ° C. for etching of Si and reacted for about 1 minute. At this time, the treatment degree should be adjusted so that the surface color of the mask is changed to white or H ₂ bubbles are not generated in a large amount from the substrate. This is because when the degree of reaction with the KOH aqueous solution is excessive, the SiO ₂ nano trench mask may also be damaged so that the entire Si substrate may be etched by the KOH aqueous solution. Subsequently, the substrate on which the Si nano trench was formed was reacted in a diluted HF solution (H ₂ O: HF (50%) = 2: 1 volume ratio) for 1 to 3 minutes to remove the SiO ₂ nano trench mask. The resulting Si nano trench is shown in atomic force micrographs of low magnification and high magnification of FIGS. 2F and 2G.

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

According to the etching method of the present invention, it is economical and simple compared to the existing method requiring expensive mechanical equipment and complicated pretreatment process for etching, and also does not use toxic chemicals to the environment and the body, and is environmentally friendly, and has a diameter of 0.5 By using the carbon nanotubes of 300 to 300 nm it is possible to manufacture a nano trench of the insulating layer having a width of 0.5 to 500 nm difficult to implement by the conventional method. In addition, it is possible to provide a nanostructure for a high density integrated device using the nano trench of the insulating layer.

Claims (19)

Forming an insulating layer on the substrate; Forming carbon nanotubes on the insulating layer; And Forming a nano trench in the insulating layer by a carbon thermal reduction reaction of the insulating layer on which the carbon nanotubes are formed; Etching method of the insulating layer using a carbon nanotube comprising a. The method of claim 1, The substrate is selected from the group consisting of silicon wafers, sapphire, glass, quartz, metals, alumina, and plastics. The method of claim 1, And wherein said insulating layer is formed of a compound comprising silicon. The method of claim 1, And the insulating layer is formed of at least one selected from the group consisting of silicon oxide, silicon dioxide, silicon nitrate, and silicon nitride. The method of claim 1, The carbon nanotubes are chemical vapor deposition (CVD), laser ablation, arc-discharge, plasma enhanced chemical vapor deposition (PECVD), vapor phase A method characterized by being formed by a method selected from the group consisting of vapor phase growth, sonication method, electrolysis and flame synthesis method. The method of claim 1, The carbon nanotubes are single-walled carbon nanotubes (SWNT), double-walled carbon nanotubes (DWNT), multi-walled carbon nanotubes (MWNT), bundles. The method is selected from the group consisting of a type of carbon nanotube (rope carbon nanotube) and the structure surrounding the catalyst with carbon particles. The method of claim 1, The carbon nanotubes having an average diameter of 0.5 to 300 nm. The method of claim 1, And the carbon melt reduction reaction is carried out while injecting oxygen and an inert gas. The method of claim 8, The oxygen content is 0.0001 to 30% of the total gas volume. The method of claim 1, The carbon melt reduction reaction is carried out at a temperature of 700 to 1200 ℃. The method of claim 1, And the nano trench of the insulating layer has an average width of 0.5 to 500 nm. The method of claim 1, Forming the carbon nanotubes and the carbon melt reduction reaction, characterized in that at the same time occur. The method of claim 12, Forming the carbon nanotubes and the carbon melt reduction reaction occurs while simultaneously injecting oxygen, hydrogen and hydrocarbons. The method of claim 13, The oxygen content is 0.01 to 2% of the total gas volume. The method of claim 13, Wherein said hydrocarbon is at least one selected from the group consisting of methane, ethane, acetylene, ethylene, butane and propane. The method of claim 1, And the upper part of the substrate on which the insulating layer is formed is deposited with a metal or transition metal catalyst. The method of claim 16, The metal or transition metal catalyst is nickel (Ni), iron (Fe), cobalt (Co), yttrium (Y), molybdenum (Mo), aluminum (Al), rhodium (Rh), palladium (Pd), gold (Au), silver (Ag), copper (Cu) or an alloy thereof. Nanostructures made using the method of any one of claims 1 to 17. The method of claim 18, The nanostructure is characterized in that the nanostructure is a metal / semiconductor nanowire, an etch structure of a substrate for a semiconductor, or an array of metal / semiconductor nanoparticles.

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