JP2004352599A - Device and method for forming carbon nanotube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and a method for forming a carbon nanotube capable of providing the carbon nanotube with a good film quality. <P>SOLUTION: The device for forming the carbon nanotube comprises at least a processing chamber, a base material holding means to arrange a base material at a specified position in the processing chamber, a carbon nanotube forming material supplying means to supply a carbon nanotube forming material and a plasma source for plasma irradiation on the base material. A carbon nanotube forming layer can be formed on the base material while the base material is irradiated with plasma by this constitution. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a CNT forming apparatus and a CNT forming method capable of forming high-quality carbon nanotubes (hereinafter, referred to as “CNT”).
[0002]
[Prior art]
The CNT (carbon nanotube) is, for example, a hollow cylindrical crystal having a high aspect ratio and a size of about several nm in diameter and about 1 μm in length. The physical properties of this CNT have been elucidated considerably in recent years or so, and are now in the field of electronic materials, composite materials (eg, for strengthening and imparting conductivity), and electronics (eg, transistors, diodes). , Wiring), electron source (for example, field emission electron source, various displays), nanotechnology (for example, scanning probe microscope (SPM) probe, nanomechatronics element), energy field (for example, hydrogen storage, electrode or capacitor material) ), General chemistry (eg, gas sensors, catalysts, organic raw materials), and the like, applications are promising, and some of these are already in the stage of practical use.
[0003]
Conventionally, CNTs are produced by using acetylene gas or the like as a carbon source, carbon arc discharge method, laser evaporation method of carbon, pyrolysis method of hydrocarbon gas, plasma CVD (chemical vapor deposition) method, etc. It has been known. Among them, the plasma CVD method is advantageous from the viewpoint of selective generation.
[0004]
[Non-patent document 1]
Monthly FPD Intelligence 1999.11 P38-P40 "Development of CVD equipment for carbon nanotube formation for Japan Vacuum FED"
[0005]
[Problems to be solved by the invention]
However, in the conventional CNT formation by the plasma CVD method, the condition range for forming a good CNT is considerably narrow. Therefore, for example, depending on the characteristics of the plasma to be used, a CNT having a good structure cannot be obtained. There was a drawback that there were many.
[0006]
An object of the present invention is to provide a CNT forming apparatus and a CNT forming method which have solved the above-mentioned drawbacks of the prior art.
[0007]
It is another object of the present invention to provide a CNT forming apparatus and a CNT forming method capable of providing CNTs having good film quality.
[0008]
[Means for Solving the Problems]
As a result of intensive studies, the present inventor has found that simultaneously or selectively irradiating plasma or radicals obtained by microcathode discharge onto a substrate in the presence of a CNT forming gas is extremely important for achieving the above object. I found it to be effective.
[0009]
The CNT forming apparatus of the present invention is based on the above findings, and more specifically, a processing chamber; a substrate holding means for arranging a substrate at a predetermined position in the processing chamber; and supplying a carbon nanotube forming material. And a plasma source for irradiating the substrate with plasma (and / or radical molecules or atoms generated by the plasma or positive / negative ions). An apparatus for forming a carbon nanotube-forming layer on the substrate while irradiating the substrate with the plasma.
[0010]
According to the present invention, further, while irradiating a plasma on a substrate disposed in the processing chamber, a carbon nanotube-forming material is supplied onto the substrate to form a carbon nanotube-forming layer on the substrate. A method for forming a carbon nanotube is provided.
[0011]
According to the present invention having the above structure, it is extremely easy to form a controllable conductive layer or wiring layer by generating carbon nanotubes (CNT) between metals (for example, electrodes) on a substrate to be processed.
[0012]
Since carbon nanotubes have a property of selectively growing in the direction of an electric field, in the present invention, it is easy to configure a process using this property.
[0013]
At this time, a DC or AC electric field may be applied between the electrodes on which the CNTs are to be formed on the substrate to be processed. Such a structure may be provided on the base material in some cases.
[0014]
Since the plasma source used in the present invention operates even under atmospheric pressure, it can irradiate radicals at a much higher concentration than the conventional remote plasma method. Therefore, according to the present invention, the efficiency of the CNT formation process can be significantly improved.
[0015]
In the CNT forming process, it is desirable to heat the substrate temperature to 400 ° C. or higher.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described more specifically with reference to the drawings as necessary. In the following description, “parts” and “%” representing quantitative ratios are based on mass unless otherwise specified.
(CNT formation process)
In the present invention, the following three types can be used as the CNT forming process.
(1) Plasma process
(2) Radical process
(3) Plasma process emphasizing radicals
When the “plasma process” is used, a sheath is formed between the substrate surface and the plasma in the plasma, and CNT tends to grow in a direction of an electric field generated in the sheath. Therefore, CNTs may be formed in unnecessary portions, and post-processing for removing such extra CNTs may be required.
[0017]
In the case of using a radical process, an electric field is applied between predetermined electrodes (metals), and the type of radical molecules or atoms and the energy thereof are varied to selectively irradiate the substrate with a reaction. Can grow CNTs selectively.
[0018]
When using the above-described radical process or radical-enhanced plasma process, in order to selectively irradiate the radical, a plasma source of a porous hollow cathode discharge type as described later is used, and a "drawing voltage" Can be used as a radical irradiation source.
[0019]
(One embodiment of plasma source)
One embodiment of a plasma source that can be used in the present invention will be described with reference to the schematic sectional view of FIG. 1, the schematic plan view of FIG. 2, and the partial schematic sectional views of FIGS. For comparison, FIG. 5 shows a schematic cross-sectional view of a conventional plasma source (CNT is formed by a simple plasma CVD method in a processing chamber).
[0020]
FIG. 1 is a schematic cross-sectional view showing one embodiment of a CNT forming apparatus including a plasma source according to the present invention. Referring to FIG. 1, a plasma source 1 according to the present invention in this embodiment includes a chamber 2 to which a gas is supplied, and a plurality of gas-permeable electrode holes 3 arranged on the gas outflow side of the chamber 2. And the hollow cathode electrode member 4. Referring to FIGS. 2 and 3, hollow cathode electrode member 4 includes a pair of perforated conductor members 4b combined via a perforated spacer 4a made of a dielectric material.
[0021]
As shown in FIG. 1, a DC power supply 6 is connected so that a voltage can be applied between a pair of perforated conductor members 4b, and a voltage can also be applied between the perforated conductor member 4b and the chamber 2. DC power supply 7 is connected as described above. As a result, a voltage is applied between the pair of perforated conductor members 4b while a gas is flowing through the electrode holes 3, and a DC driven micro-cathode discharge is started, and plasma is generated in the region P of FIG. When the plasma is generated, the electrons collide with the inner wall of the electrode hole 3, and electrons (secondary electrons) are emitted from the inner wall by the γ (gamma) action. In the present invention, electrons are emitted by the γ action, and the electrons collide with the next molecule to generate an α (alpha) action for ionizing the molecule, thereby maintaining the discharge.
[0022]
As shown in the partial schematic cross-sectional view of FIG. 4, the hollow cathode electrode member 4 described above may have a plurality of pairs of perforated conductor members 4b combined via perforated spacers 4a as necessary. Good. Such an embodiment having a plurality of pairs of perforated conductor members 4b is preferable because it can increase the pressure drop and prevent the plasma concentration from attenuating.
[0023]
(CNT forming equipment)
The CNT forming apparatus according to the present invention includes a processing chamber 10, a substrate holding unit 11 for disposing a substrate 12 at a predetermined position in the processing chamber 10, and a rotatable member. And a plasma source having the above-described configuration for irradiating the plasma. The substrate holding means 11 can be heated to about 600 ° C. by installing a heater or the like inside.
[0024]
In the embodiment of the CNT forming apparatus shown in FIG. Plasma processing of the object to be processed (for example, a wafer) 12 becomes possible. A bias power supply (not shown) 13 is connected to the susceptor 11 so that a predetermined voltage (for example, RF voltage) can be applied to the susceptor 11.
[0025]
The plasma source of the present invention having the above-described configuration can generate plasma based on good micro-cathode discharge relatively without being influenced by the gas pressure at the time of driving the plasma source. In other words, the plasma source of the present invention is a so-called low-pressure plasma (pressure: about 0.133 Pa to 13.3 Pa; the density of electrons, ions, and radicals is generally 10¹¹-10¹²/ Cm³Atmospheric pressure plasma (pressure: about 101.3 kPa; density of electrons, ions and radicals is generally 10^Fifteen/ Cm³Degree) can be easily realized. When such atmospheric pressure plasma is used, stable discharge can be performed under atmospheric pressure, and so-called non-equilibrium plasma in which the electron temperature is higher than the gas temperature can be suitably realized.
[0026]
On the other hand, the conventional plasma source or CNT forming apparatus has a disadvantage that the dynamic range of the acceleration / deceleration energy of the particles is small because the plasma is generated in the plasma chamber.
[0027]
(Configuration of each part)
Hereinafter, each part constituting the plasma source or the CNT forming apparatus of the present invention will be described in detail.
[0028]
(Chamber)
As for the chamber 2 for supplying gas shown in FIG. 1, as long as a gas for plasma generation can be supplied into the chamber 2 and a plasma source can be arranged on the gas outlet side, the chamber 2 The structure, size, material, and the like are not particularly limited.
[0029]
(Hollow cathode electrode member)
The hollow cathode electrode member 4 has a plurality of electrode holes 3. The number and size of the electrode holes 3, the thickness of the hollow cathode electrode member 4, and the like are not particularly limited as long as plasma can be generated in the electrode holes 3.
[0030]
(Perforated spacer member)
As described above, the hollow cathode electrode 4 includes at least one pair of perforated conductor members combined via the perforated spacer member made of a dielectric. The material, size, thickness, and the like of the perforated spacer member 4a are not particularly limited as long as plasma can be generated in the electrode hole 3.
[0031]
(Perforated conductor member)
The material, size, thickness, and the like of the perforated conductor member 4b are not particularly limited as long as plasma can be generated in the electrode hole 3.
[0032]
(gas)
The gas to be supplied into the chamber 2 that can be used in the present invention is not particularly limited as long as it is a gas capable of forming CNTs, and various gases depending on the use of the CNT to be generated can be used. That is, generally, various inert gases (for example, noble gases) can be used as the plasma generation gas, and various carbon-containing gases (for example, acetylene) can be used as the CNT forming gas. If necessary, another gas may be added. Gases that can be suitably used in the present invention are exemplified below.
Gas for plasma generation: Inert gas
Carbon-containing gas: CH-based gas
(Other aspects)
5 and 6 show another embodiment of the present invention. In these embodiments, the uppermost part of the electrode 4 is formed of the dielectric 4a in order to facilitate the concentration of the discharge in the electrode hole 3.
[0033]
(Plasma generation principle)
In the present invention, the generation principle of the plasma is not particularly limited as long as the plasma can be generated in the electrode hole 3. That is, in the embodiment of FIG. 1 described above, a direct current (DC) voltage is applied between the pair of perforated conductor members 4b, but this may be a high frequency or a microwave.
[0034]
(Base material)
When the plasma source or the CNT forming apparatus of the present invention is used, various substrates (for example, substrates for electronic devices such as wafers) can be subjected to plasma processing. The above-mentioned base material that can be used in the present invention is not particularly limited, and may be appropriately selected from one or a combination of two or more known base materials. Examples of such base materials include, for example, semiconductor materials, liquid crystal device materials, and the like. Examples of the semiconductor material include, for example, a material mainly containing single crystal silicon, SiC, GaAs, and the like.
[0035]
(CNT formation method)
In the CNT forming method of the present invention, a CNT forming material is supplied onto a substrate placed in a processing chamber while plasma is irradiated on the substrate to form a CNT layer on the substrate.
(On the substrate)
In the present invention, "on the base material" is sufficient if the CNT to be formed is located above the base material (that is, above the side on which the layers constituting the electronic device of the base material are formed). In other words, other insulating layers, conductor layers, semiconductor layers, and the like may be disposed therebetween. Further, needless to say, a plurality of various insulating layers, conductor layers, semiconductor layers, and the like, including CNTs to be formed in the present invention, may be arranged as necessary.
[0036]
(Thickness)
In the present invention, the thickness of the CNT layer to be formed is not particularly limited, but is preferably several tens of degrees (in the case of forming a channel) to about 2 μm (in the case of wiring).
[0037]
As described above, according to the present invention, it is easy to form CNTs between metals (for example, electrodes). The metal that can be used at this time is preferably a transition metal from the viewpoint of catalytic action. Alternatively, an electrode formed by spraying transition metal (Ni, Co, Pd, etc.) powder on a metal surface or an electrode formed by selectively controlling the position is desirable.
[0038]
In the present invention, in addition to the above, a carbon nanocoil can also be formed using a NiFe catalyst (for details of such carbon nanocoil or CNT formation, see, for example, the document Diamond and Related Materials, 9). (2000), 847-851; Electron Theory A, Vol. 118, No. 12 (1998), pp. 1425-1428).
(Example of suitable conditions)
In the present invention, for example, the following conditions can be suitably used.
Microwave: 2 kW / cm²(A DC voltage may be applied to the hollow cathode plasma source.) 1 to 10 W / cm²
Gas: Ar 1000 sccm + H₂  100 sccm, or
Kr or He 1000sccm + H₂  100sccm
Pressure: 1 to 760 Torr (133 to 10 × 10⁴Pa)
Substrate temperature: 500 ± 50 ° C
Processing time: 60-600 seconds
(Other aspects)
Since the holes constituting the microcathode electrode are relatively narrow, when acetylene flows from above, contamination such as sputtering tends to occur relatively easily inside the microcathode. In such a case, for example, in the present invention, H is added together with an inert gas (for example, krypton) from above the plasma source.₂A gas is flowed, and acetylene (C₂H₂) Or flowing methane gas or the like to form CNTs inside the microcathode. Further, a gas containing a transition metal such as Ni, Fe, Co, etc., for example, Ni (CO)₄Alternatively, an organic metal gas may be introduced.
[0039]
In order to grow CNTs, a site to which a catalyst is provided (catalyst site) is often required. The method for forming the catalyst site in the present invention is not particularly limited. For example, the catalyst site can be formed of nickel or the like (for details of such formation of the catalyst site, see, for example, the document J. Appl. Phys. 92 6188). (2003)).
(Other embodiment 2)
Another embodiment of the plasma source usable in the present invention will be described. The plasma source in this aspect is a plasma source including at least a chamber to which gas is to be supplied and a hollow cathode electrode member disposed on the gas outlet side of the chamber and having a plurality of electrode holes through which gas can pass. Microcathode plasma discharge is possible in the electrode holes of the hollow cathode electrode member. According to such an embodiment, it is possible to perform discharge using a plasma source capable of generating highly efficient and high-density plasma.
(Specific embodiment of plasma source)
One embodiment of the plasma source of the present invention will be described with reference to the schematic sectional view of FIG.
[0040]
FIG. 7 is a schematic cross-sectional view showing one embodiment of a plasma processing apparatus including the plasma source of the present invention. Referring to FIG. 7, a plasma source 51 of the present invention in this embodiment includes a chamber 52 to which gas is supplied and a plurality of electrode holes 53 arranged on the gas outflow side of the chamber 52 and through which gas can pass. And the hollow cathode electrode member 4.
[0041]
As shown in FIG. 7, a DC power supply 6 is connected so that a voltage can be applied between the pair of perforated conductor members 54b, and a voltage can be applied between the perforated conductor member 54b and the chamber 52. DC power supply 57 is connected as described above. As a result, a voltage is applied between the pair of perforated conductor members 54b while a gas flows through the electrode holes 53, and a DC-driven microcathode discharge is started to generate plasma. A plurality of these pairs are provided in the vertical direction, and a voltage is applied to each pair independently from the outside. When the plasma is generated, the electrons collide with the inner wall of the electrode hole 53, and electrons (secondary electrons) are emitted from the inner wall by γ (gamma) action. In the present invention, electrons are emitted by the γ action, and the electrons collide with the next molecule to generate an α (alpha) action for ionizing the molecule, thereby maintaining the discharge.
[0042]
Alternatively, an electrode that is electrically separated from the chamber 52 may be provided, and a DC or AC electric field may be applied between the electrode and the chamber to generate plasma in the chamber 52. Microwaves may be used. In order to increase the γ action, the metal of the electrode part has a high plasma resistance, and a member that efficiently generates secondary electrons can be selected, or a material in which the electrode part is coated with carbon nanotubes can be used. is there.
[0043]
The surface is coated with a metal material having a small work function value such as Cs having a high electron emission efficiency from the surface. Alternatively, a structure in which an insulator is coated on the electrode metal surface to lower the apparent work function value is also possible.
[0044]
In the embodiment of the plasma processing apparatus shown in FIG. 7, a plasma is generated based on microcathode discharge in the electrode hole 53, and the susceptor 61 on the susceptor 61 arranged in the plasma processing chamber 60 equipped with the plasma source 51 of the present invention is mounted. The plasma processing of the object to be processed (for example, a wafer) 62 becomes possible. A bias power supply 63 is connected to the susceptor 61 so that a predetermined voltage (for example, an RF voltage) can be applied to the susceptor 61.
[0045]
The plasma source of the present invention having the above-described configuration can generate plasma based on good micro-cathode discharge relatively without being influenced by the gas pressure at the time of driving the plasma source. In other words, the plasma source of the present invention is a so-called low-pressure plasma (pressure: about 0.133 Pa to 13.3 Pa; the density of electrons, ions, and radicals is generally 10¹¹-10¹²/ Cm³Atmospheric pressure plasma (pressure: about 101.3 kPa; density of electrons, ions and radicals is generally 10^Fifteen/ Cm³Degree) can be easily realized. When such atmospheric pressure plasma is used, stable discharge can be performed under atmospheric pressure, and so-called non-equilibrium plasma in which the electron temperature is higher than the gas temperature can be suitably realized.
(Configuration of each part)
Hereinafter, each part constituting the plasma source of the embodiment of FIG. 7 will be described in detail.
(Chamber)
As for the chamber 2 for supplying gas shown in FIG. 7, as long as a gas for plasma generation can be supplied into the chamber 52 and a plasma source can be arranged on the gas outlet side, the chamber 2 The structure, size, material, and the like are not particularly limited.
(Plasma generation principle)
In the present invention, the generation principle of the plasma is not particularly limited as long as the plasma can be generated in the electrode hole 3. That is, in the embodiment of FIG. 7, a direct current (DC) voltage is applied between the pair of perforated conductor members 54b, but this may be a microwave.
[0046]
In the mode in which a DC voltage is applied, the following conditions can be suitably used.
Voltage: 1 kV or more
In a mode of applying a microwave (for example, 2.45 GHz), the following conditions can be suitably used.
[0047]
Microwave: 0.5W / cm²It is preferable that it is above. (However, it may be appropriately adjusted according to the area of the electrode)
(Other aspect 3)
8 (a) and 8 (b) show another embodiment of the hollow cathode electrode 54. FIG.
[0048]
Referring to FIG. 8A, in such an embodiment, a hollow cathode electrode 54 including a pair of perforated conductive members 54 b combined via a perforated spacer member 54 a is connected through a dielectric 70. It has the same configuration as that of the embodiment of FIG. 7 except that it is attached to a grounded metal member 71. In the configuration of FIG. 8, the perforated spacer member 54a is made of, for example, alumina (Al).₂O₃), Made of a dielectric material such as quartz, and the perforated conductive member 54b is made of a metal such as Si, Cu, MO, W, and SUS.
[0049]
Referring to FIG. 8B, in such an embodiment, hollow cathode electrode 4 including a plurality of pairs of perforated conductive members 54 b combined via perforated spacer members 54 a is connected via dielectric 20. 7, except that the extraction electrode 72 is disposed below the hollow cathode electrode 4.
[0050]
The extraction electrode 72 is grounded via a variable voltage power supply 73, and a voltage V is applied to the extraction electrode 72. When the voltage V = 0 or a floating potential, radicals or plasma are extracted from the extraction electrode 72, and when the voltage V> 0, electrons or ions having a negative charge are extracted from the extraction electrode 72. When the voltage V <0, positively charged ions are extracted from the extraction electrode 72. When extracting plasma, the extraction electrode 72 can be omitted. Further, in the process of extracting positive and negative ions, positive and negative ions may collide with the side wall to neutralize and extract radicals having energy.
[0051]
In the embodiment of FIG. 8B, the distance d between the perforated conductive member 54b closest to the extraction electrode 72 and the extraction electrode 72 depends on the operating conditions of the hollow cathode electrode 54 and / or the extraction electrode 72. It is preferably about 1 to 10 mm.
[0052]
In the present invention, it is possible to dramatically increase the particle density and stabilize discharge. Further, from the viewpoint that the particles can be irradiated in a four-dimensional (spatiotemporally) manner, the microcathode is preferably of “multistage” (preferably three or more). From the viewpoint of improving the characteristics of the plasma, it is preferable to form a multistage with three or more electrodes. In the case of a single-stage micro-cathode, for example, it is preferable to apply a "differential pressure" between the gas supply side and the plasma generation side from the viewpoint of increasing the process dynamics.
[0053]
In the plasma source of the present invention, the high pressure side may be at atmospheric pressure. The plasma generation side may be at atmospheric pressure or may be at a lower pressure than atmospheric pressure. From the efficiency of plasma generation, it is preferable that the pressure on either one (or both) of the gas supply side and the plasma generation side be higher.
[0054]
The microcathode source of the present invention can be used alone as a plasma source, but may be combined with a conventional plasma generating means (for example, a parallel plate) as necessary. In this way, when combined with the conventional plasma generating means, it is possible to inject various particles into the conventional plasma process, and it is possible to dramatically improve the performance of the process under the conventional process conditions. Benefits can be obtained.
[0055]
Furthermore, a large number of microcathodes are provided in a plane, and the holes of the microcathodes are set as "addresses", and the on / off of each hole or the plasma intensity and / or the planar distribution of the plasma intensity are controlled by a computer or the like. Adjustment is also possible.
[0056]
Further, by the above-described planar control of the plasma intensity, it is possible to generate plasma having a shape corresponding to the shape of the substrate to be subjected to plasma processing. Such planar control of the plasma intensity also enables selective etching of the substrate (eg, etching without using a resist).
[0057]
Further, in the electrodes of the multi-stage micro-cathode, the potential applied to each electrode can be made different to adjust the plasma intensity in the vertical direction. In this case, it is possible to control the generated plasma to be rich in neutral particles by making the potentials applied to the respective electrodes different. For example, in a vertical multi-stage electrode, by generating plasma only in the upper part, the intensity of the plasma and the particle density can be controlled with high precision.
[0058]
In the present invention, means for monitoring the intensity of the plasma generated by the plasma source is not particularly limited. From the viewpoint of high-precision particle density control, a sensor (e.g., a light emission, radical, electron density measurement device) is provided on the surface opposite to the side on which the plasma source is provided, and the intensity of the plasma is monitored by the sensor. What is necessary is just to feed back to a plasma source.
[0059]
In the present invention, it is also possible to increase the γ-electron efficiency of the plasma source by generating CNTs (carbon nanotubes) on each electrode constituting the plasma source (for details of such a CNT forming method, It can be formed by increasing the temperature of the electrode material by thermal CVD or plasma CVD.)
[0060]
9 (an example in which the plasma source has a four-stage configuration) and FIG. 10 (an example in which the plasma source has a three-stage configuration) are schematic cross-sectional views showing still another example of the configuration of the plasma source that can be used in the present invention.
[0061]
As shown in FIG. 11, the apparatus of the present invention forms a plurality of multi-arrays on a two-dimensional plane, and further arranges a plurality of vertical electrodes vertically in one array. A three-dimensional multi-array plasma source ”or a“ three-dimensional multi-array particle supply device ”can be configured.
[0062]
A voltage can be independently applied to each pair of these three-dimensional multi-array electrodes. A sample 62 having a three-dimensional shape is placed on the susceptor in the chamber shown in FIG. For example, as shown in FIGS. 12 and 13, for a sample having a two-dimensional or three-dimensional shape, appropriately controlling the power supply to the FDD according to the shape of the sample (not only two-dimensional but three-dimensional). Thus, it is possible to perform plasma, charged particle, and radical treatment.
[0063]
Conventionally, a plasma that is at least larger than the shape of the object to be processed was required, but this device can flexibly change the shape of the plasma according to the size and size of the object to be processed. It is. In addition, in the case of ordinary plasma processing, a seamer is generated between the plasma and the object to be processed, and it is impossible to three-dimensionally irradiate ions through the seamer to change the ion energy according to the shape. Met.
[0064]
In the apparatus of the present invention, energy is controlled by controlling, for example, the voltage of the extraction electrode shown in FIG. 14 or the voltage between the anode and cathode electrodes of the pair of vertical multi-electrodes shown in FIG. Irradiation of high-speed positive / negative ions and high-speed radicals becomes possible three-dimensionally. Therefore, a three-dimensional structure having a desired shape can be directly processed or deposited without using a mask pattern or the like.
[0065]
For example, the on / off modulation of each plasma source can be independently performed on the order of several μsec to msec. Further, these processes can be controlled in time series, and a four-dimensional plasma process using a four-dimensional multi-array electrode is possible.
[0066]
16 to 20 show configuration examples of a microplasma source usable in the present invention.
(Gas deposition)
According to the experiment of the present inventors, the plasma tends to be stabilized by introducing the Kr gas or the Xe gas. From such a point, He is preferable to Ar gas, and Kr or Xe is preferable to He gas.
(Electrode structure)
As shown in FIG. 21, the discharge tends to be more stable when the insulator is entangled deeper than the conductor electrode by 0.1 mm.
(Kr emission intensity)
FIG. 22 shows the measurement results of the Kr emission intensity by the present inventors.
[0067]
Plasma diameter: φ0.1mm
Metal Cu: 1 mm
Insulator Al₂O₃: 0.2mm
This experimental condition: Kr gas was allowed to flow from above, and 175 V and 3.35 mA were applied to the first and second electrode pairs under atmospheric pressure. As shown in the figure, plasma was applied to the cathode (A) and the cathode (B). Was generated, and the emission intensity of Kr (877.7 nm and 760.2 nm) at that time was observed with a photodiode to obtain 41 nW. Next, 350 V and 1.45 mA were applied to the third electrode-cathode electrode (C) to obtain a photodiode output of 61 nW. Thus, it was observed that the output of the multistage electrode increased in proportion to the number of plasmas.
[0068]
<Experimental example 1>
In this apparatus, H (H) is used as gas (A) from the top of the multi-electrode.₂/ He gas is introduced from atmospheric pressure.
[0069]
Vacuum is exhausted through the multi-electrode, and the pressure in the lower reaction vessel is maintained at about 10 Torr. CH from lower electrode₄/ H₂Or C₂H₂/ H₂Gas is introduced and SiO₂Si substrate (SiO₂/ Si) grow CNTs on the substrate. The substrate temperature is set to 600 ° C. The distance between the multi-electrode using the substrate as a sample and the sample is about 10 mm.
[0070]
H in multiple electrodes₂+ E → H + H He + e → He⁺A large amount of H radicals are generated by the + e + e reaction and introduced into the reaction vessel. As in Embodiment 1, high-speed H radicals and energy of about 5 eV or less are applied to the substrate.
[0071]
Fast H radical and CH₃Or C₂The CNT grows on the substrate by the interaction with the radical. By this method, H radical density and C₂And the like, and both radicals can be controlled independently, so that defect-free CNTs can be formed at high speed.
[0072]
Further, by applying a high-frequency power of 100 MHz between the lowermost electrode of the multi-electrode and the substrate electrode 2 as shown in FIG.₄/ H₂Or C₂H₂/ H₂Alternatively, a gas plasma in which a gas containing Ni or the like is added to the mixed gas may be applied to insert high-density H radicals into the plasma.
[0073]
【The invention's effect】
As described above, according to the present invention, a CNT forming apparatus and a CNT forming method capable of providing CNTs having good film quality are provided.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view showing an example of a plasma source or CNT forming apparatus of the present invention.
FIG. 2 is a schematic plan view showing an example of a hollow cathode electrode member constituting the plasma source of the present invention.
FIG. 3 is a schematic sectional view showing an example of a layer configuration of a hollow cathode electrode member constituting the plasma source of the present invention.
FIG. 4 is a partial schematic cross-sectional view showing another example of the layer configuration of the hollow cathode electrode member constituting the plasma source of the present invention.
FIG. 5 is a schematic sectional view showing another example of the plasma source or CNT forming apparatus of the present invention.
FIG. 6 is a schematic cross-sectional view showing another example of the layer configuration of the hollow cathode electrode member constituting the plasma source of the present invention.
FIG. 7 is a schematic sectional view showing an embodiment of another plasma source usable in the present invention.
8A is a partial schematic cross-sectional view showing another embodiment of the hollow cathode electrode, and FIG. 8B is a partial schematic cross-sectional view showing another embodiment of the hollow cathode electrode.
FIG. 9 is a schematic sectional view showing another example of the configuration of the plasma source of the present invention (an example in which the plasma source has a four-stage configuration).
FIG. 10 is a schematic sectional view showing another example of the configuration of the plasma source of the present invention (an example in which the plasma source has a three-stage configuration).
FIGS. 11A and 11B are a schematic cross-sectional view and a schematic plan view illustrating an example of a practical configuration of a plasma source according to the present invention. FIGS.
FIG. 12 is a schematic perspective view showing an example of a practical configuration of a plasma source according to the present invention.
FIG. 13 is a schematic plan view (view from above the apparatus) showing an example of a practical configuration of the plasma source of the present invention.
FIG. 14 is a conceptual diagram (schematic sectional view) showing an example of the generation of a fast neutral radical in the present invention.
FIG. 15 is a conceptual diagram (schematic sectional view) showing an example of the generation of a fast neutral radical in the present invention.
FIG. 16 is a schematic sectional view showing another example of the practical configuration of the plasma source of the present invention.
FIG. 17 is a schematic sectional view showing another example of the practical configuration of the plasma source of the present invention.
FIG. 18 is a schematic sectional view showing another example of the practical configuration of the plasma source of the present invention.
FIG. 19 is a schematic sectional view showing another example of the practical configuration of the plasma source of the present invention.
FIG. 20 is a schematic sectional view showing another example of the practical configuration of the plasma source of the present invention.
FIG. 21 is a schematic cross-sectional view showing one example of an electrode configuration that can be suitably used in the plasma source of the present invention.
FIG. 22 is a graph showing an example of a relationship between the number of vertical electrode pairs and Kr emission intensity.
FIG. 23 is a schematic sectional view showing an example of a combination of the plasma source of the present invention and a parallel plate type plasma electrode.

Claims (12)

A processing chamber;
Substrate holding means for arranging the substrate at a predetermined position in the processing chamber,
Means for supplying a carbon nanotube forming material for supplying a carbon nanotube forming material,
A carbon nanotube forming apparatus including at least a plasma source for irradiating the substrate with plasma,
A carbon nanotube forming apparatus, wherein a carbon nanotube forming layer can be formed on the substrate while irradiating the substrate with the plasma. 2. The plasma source according to claim 1, wherein the plasma source includes at least a chamber to which a gas is to be supplied, and a hollow cathode electrode member having a plurality of gas-permeable electrode holes disposed on a gas outlet side of the chamber. 3. The carbon nanotube forming apparatus according to item 1. The plasma source is
A chamber for supplying gas;
At least a hollow cathode electrode member having a plurality of gas-permeable electrode holes disposed on a gas outlet side of the chamber; and enabling microcathode plasma discharge in the electrode holes of the hollow cathode electrode member. The carbon nanotube forming apparatus according to claim 1, which is a plasma source. The carbon nanotube formation according to claim 3, wherein the hollow cathode electrode is a plasma source that includes a plurality of pairs of perforated conductor members and that enables microcathode discharge at a position corresponding to the pair of perforated conductor members. apparatus. The carbon nanotube forming apparatus according to claim 3, further comprising an anode electrode corresponding to the hollow cathode electrode, wherein the anode electrode has a hole for plasma penetration. The carbon nanotube forming apparatus according to any one of claims 3 to 5, wherein the electrode is a multi-stage electrode having three or more stages. The carbon nanotube forming device according to claim 3, wherein the electrode is a three-dimensional electrode. The carbon nanotube forming apparatus according to claim 7, wherein the three-dimensional electrode is an electrode capable of independently operating individual electrode elements. The carbon nanotube forming apparatus according to any one of claims 3 to 8, wherein a potential to be applied to the electrode can change with time. A method for forming a carbon nanotube, comprising: supplying a carbon nanotube-forming material onto a substrate while irradiating the substrate with a plasma on the substrate disposed in the processing chamber; and forming a carbon nanotube-forming layer on the substrate. . The method for forming carbon nanotubes according to claim 10, wherein a distance between a plasma irradiation port of the plasma source and an electronic device substrate to be treated by the plasma is 5 mm or less. The coating method according to claim 10 or 11, wherein the coating treatment is performed near atmospheric pressure (a pressure in a range up to twice the atmospheric pressure).

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