Method and apparatus for forming graphene structure

Abstract

Provided is a method for forming a graphene structure without forming a catalytic metal layer and activating the same, the graphene structure forming method including: a step of preparing a substrate to be processed; and a step of forming a graphene structure on a surface of the substrate to be processed by using a carbon-containing gas as a film forming raw material gas in a state in which the surface of the substrate to be processed has no catalytic function, and performing remote microwave plasma CVD.

Description

TECHNICAL FIELD

[0001] The present application relates to a method of forming a graphene structure and a forming apparatus. BACKGROUND

[0002] Graphene is a thin film of graphite formed on a substrate to a thickness of 1 to several tens or several hundred atomic layers, and as a graphene structure, a carbon nanowall (hereinafter also referred to as CNW) in which a few layers of graphene sheets grow at an angle, typically perpendicularly, with respect to the substrate is known in addition to the usual graphene formed in parallel on the substrate.

[0003] Graphene is a material in which carbon atoms are aggregated in a hexagonal structure by covalent bonds (sp 2 bonds), and exhibits excellent electronic properties, i.e., mobility of 200,000 cm 2 Vs or more, 100 times or more that of silicon (Si), and a current density of 10 9 A / cm 2 , 1,000 times or more that of Cu.

[0004] Due to such properties, graphene is attracting attention as a material for various applications in wiring, field effect transistor (FET) channels, barrier films, etc., and CNW is attracting attention as a material for various applications in fuel cells, field electron emission sources, or sensors, etc., according to its structural properties.

[0005] As a method of forming graphene, a method of forming a catalytic metal layer on a processed body, and then forming graphene by CVD after performing activation treatment of the catalytic metal layer is proposed, and in an embodiment, CVD using a microwave plasma is described as an example of CVD (Patent Documents 1 and 2).

[0006] In addition, as a method of forming a carbon nanowall, a method of forming a plasma atmosphere by parallel-plate capacitively coupled plasma (CCP) formation, injecting hydrogen radicals into the plasma atmosphere, and forming a carbon nanowall on the surface of a substrate is proposed (Patent Document 3).

[0007] PRIOR ART DOCUMENTS

[0008] PATENT DOCUMENTS

[0009] Patent Document 1: Japanese Patent Application Publication No. 2013-100205

[0010] Patent Document 2: Japanese Patent Application Publication No. 2014-231455

[0011] Patent Document 3: Japanese Patent Application Publication No. 2005-97113 SUMMARY

[0012] Technical problem to be solved by the invention

[0013] However, in Patent Documents 1 and 2, the substrate is limited to a catalytic metal layer, and because activation treatment of the catalytic metal layer is necessary, the steps are complicated.

[0014] In addition, in Patent Document 3, in a plasma or a region where the electron temperature is high, a growth reaction of carbon nanowalls occurs, so high-energy ions cause damage, and a polynuclear is generated from a carbon radical having a high activity, and it is difficult to improve the crystallinity.

[0015] Therefore, an object of the present application is to provide a method and an apparatus capable of forming a graphene structure without forming a catalytic metal layer and activation treatment thereof.

[0016] In addition, an object of the present application is to provide a method and an apparatus capable of forming a graphene structure including carbon nanowalls having good crystallinity with less damage caused by high-energy ions.

[0017] Technical solution for solving the technical problem

[0018] To solve the above problem, a first aspect of the present application provides a graphene structure forming method of forming a graphene structure, characterized by comprising: a step of preparing a processed substrate; and a step of forming a graphene structure on a surface of the processed substrate by performing remote microwave plasma CVD using a carbon-containing gas as a film formation raw material gas in a state where the surface of the processed substrate has no catalytic function.

[0019] A second aspect of the present application provides a graphene structure forming method of forming a graphene structure, characterized by comprising: a step of preparing a processed substrate; and a step of forming a graphene structure including carbon nanowalls on a surface of the processed substrate by performing remote microwave plasma CVD using a carbon-containing gas as a film formation raw material gas.

[0020] The graphene structure forming apparatus according to the third aspect of the present application includes: a processing container for housing a substrate to be processed; a placement table for horizontally placing the substrate to be processed in the processing container; a heating mechanism for heating the substrate to be processed; a planar slot antenna having a slot, which is disposed above the processing container via a microwave-transmissive plate, wherein the microwave-transmissive plate is formed of a dielectric material constituting a top wall of the processing container; a microwave introduction mechanism for introducing microwaves into the processing container via the slot and the microwave-transmissive plate; a gas introduction mechanism for supplying a gas including a carbon-containing gas as a film formation raw material into the processing container; an exhaust mechanism for exhausting the processing container; and a control unit for controlling the heating mechanism, the microwave introduction mechanism, the gas introduction mechanism, and the exhaust mechanism to perform the graphene structure forming method according to the first aspect or the second aspect.

[0021] The graphene structure forming apparatus according to the fourth aspect of the present application includes: a processing container for housing a substrate to be processed; a placement table for horizontally placing the substrate to be processed in the processing container; a heating mechanism for heating the substrate to be processed; a microwave introduction apparatus disposed above the processing container; a gas introduction mechanism for supplying a gas including a carbon-containing gas as a film formation raw material into the processing container; an exhaust mechanism for exhausting the processing container; and a control unit for controlling the heating mechanism, the microwave introduction apparatus, the gas introduction mechanism, and the exhaust mechanism to perform the graphene structure forming method according to the first aspect or the second aspect. The microwave introduction apparatus includes: a microwave generation unit for generating microwaves; and a plurality of microwave radiation mechanisms supplied with the microwaves distributed from the microwave generation unit, which radiate the microwaves into the processing container. The microwave radiation mechanisms include: a tuner for impedance matching; a planar slot antenna having a slot for radiating the supplied microwaves; and a microwave-transmissive plate formed of a dielectric material, which is adjacently disposed directly below the planar antenna and is embedded in a top wall of the processing container. The control unit controls the heating mechanism, the microwave introduction apparatus, the gas introduction mechanism, and the exhaust mechanism to perform the graphene structure forming method according to the first aspect or the second aspect.

[0022] Effects of the Invention

[0023] According to the first aspect of the present application, a graphene structure is formed on a surface of a substrate to be processed by performing remote microwave plasma CVD using a carbon-containing gas as a film formation raw material gas, without using a catalytic metal layer and without performing an activation process of the catalytic metal layer.

[0024] In addition, according to the second aspect of the present application, by using a carbon-containing gas as a film formation raw material gas, a graphene structure including carbon nanowalls is formed on the surface of the substrate to be processed by remote microwave plasma CVD, and thus a carbon nanowall having a high crystallinity and having less damage caused by high-energy ions can be formed. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a flowchart showing a method of manufacturing a graphene structure according to the first embodiment.

[0026] Figure 2 is a cross-sectional view showing a specific example of the configuration of a substrate to be processed used in the method of manufacturing a graphene structure according to the first embodiment.

[0027] Figure 3 is a cross-sectional view showing a state in which a graphene structure is formed on a substrate to be processed by the method of manufacturing a graphene structure according to the first embodiment.

[0028] Figure 4 is a flowchart showing a method of manufacturing a graphene structure according to the second embodiment.

[0029] Figure 5 is a cross-sectional view showing a state in which a graphene structure including CNWs is formed on a substrate to be processed by the method of manufacturing a graphene structure according to the second embodiment.

[0030] Figure 6 is a cross-sectional view showing a first example of a processing apparatus suitable for implementation of the method of forming a graphene structure according to the first and second embodiments of the present application.

[0031] Figure 7 is a cross-sectional view showing a second example of a processing apparatus suitable for implementation of the method of forming a graphene structure according to the first and second embodiments of the present application.

[0032] Figure 8 is a structural view schematically showing a microwave introduction apparatus of the processing apparatus of Figure 7

[0033] Figure 9 is a cross-sectional view schematically showing a microwave irradiation mechanism of the processing apparatus of Figure 7

[0034] Figure 10 is a bottom view schematically showing a top wall portion of a processing container of the processing apparatus of Figure 7

[0035] Figure 11 is an SEM photograph of a graphene structure formed in Example 1. ​​​

[0036] Figure 12 is a graph showing a Raman spectrum of the graphene structure formed in Example 1.

[0037] Figure 13 is an SEM photograph showing the graphene structure formed in Example 2.

[0038] Figure 14 is a TEM photograph showing the graphene structure formed in Example 3, (a) shows that the graphene structure is grown, (b) is a magnified view showing CNWs in the graphene structure, (c), (d) are further magnified views showing A and B regions of (b).

[0039] Figure 15 is a TEM photograph showing the graphene structure formed in Example 3, (a) shows that the graphene structure is grown, (b) is a magnified view showing a portion of graphene and CNWs of the graphene structure, (c), (d) are further magnified views showing C and D regions of (b).

[0040] Figure 16 is a graph showing the results of the treatment under Condition 1 in Example 4, (a) is an SEM photograph at this time, (b) is a TEM photograph of CNWs contained in the graphene structure, (c) is a Raman spectrum of the CNWs.

[0041] Figure 17 is a graph showing the results of the treatment under Condition 2 in Example 4, (a) is an SEM photograph at this time, (b) is a TEM photograph of the graphene structure, (c) is a Raman spectrum of the graphene structure.

[0042] Figure 18 is an SEM photograph showing the graphene structure formed in Example 5.

[0043] Figure 19 is an SEM photograph showing the graphene structure formed in Example 6.

[0044] Figure 20 is an SEM photograph showing the configuration of the graphene structure grown under the condition of changing the pressure in Example 7.

[0045] Figure 21 is a graph showing a Raman spectrum when the remote microwave plasma CVD treatment is performed by changing the temperature in Example 8.

[0046] Figure 22 is an SEM photograph showing the graphene structure formed in Example 9.

[0047] Figure 23 is a graph showing a Raman spectrum of the graphene structure formed in Example 9.

[0048] Reference Signs List

[0049] 1, 101: processing container

[0050] 2, 102: stage

[0051] 3: microwave introduction mechanism

[0052] 4, 103: gas supply mechanism

[0053] 5: exhaust portion

[0054] 6, 106: control portion

[0055] 82, 104: exhaust device

[0056] 100, 200: processing device

[0057] 105: microwave introduction device

[0058] 300: processed substrate

[0059] 301: semiconductor substrate

[0060] 302: insulating film

[0061] 303: barrier film

[0062] 304: metal film

[0063] 310, 320: graphene structure

[0064] 321: graphene

[0065] 322: CNW

[0066] W: wafer DETAILED DESCRIPTION

[0067] Hereinafter, an embodiment of the present application will be specifically described with reference to the accompanying drawings.

[0068] Embodiment of the method for manufacturing graphene structure

[0069] (1st Embodiment)

[0070] First, the first embodiment of the method for manufacturing a graphene structure will be described. In the above-described Patent Documents 1 and 2, in order to grow graphene having good crystallinity with high efficiency at as low a temperature as possible, a catalytic metal film of Ni or the like, which becomes a catalyst for promoting the growth of graphene, is formed as a substrate, and after the catalytic metal layer is activated by plasma of H2 gas as a reducing gas and N2 gas as a nitrogen-containing gas, graphene is grown by plasma CVD. That is, in the cited documents 1 and 2, a film formation raw material gas (precursor) is dissociated by a catalytic reaction generated based on the metal catalytic layer, thereby growing graphene.

[0071] As a result of the inventors' research, it was found that by introducing microwaves into a processing vessel, generating plasma using a microwave electric field, and causing the plasma (remote microwave plasma) diffusing from the plasma generation region to act on a processed substrate present at a position apart from the plasma generation region, a carbon-containing gas as a film formation raw material gas (precursor) can be dissociated into a state suitable for the growth of graphene at a relatively low temperature, and a graphene structure having good crystallinity can be formed without using a metal catalytic layer after activation treatment, which is necessary in the prior art.

[0072] In the cited documents 1 and 2, it is described that a microwave plasma is used for plasma CVD when forming graphene, and it is considered that dissociation of a film formation raw material gas (precursor) based on catalytic action of a metal catalytic layer is necessary regardless of the method of plasma CVD, and unlike this, the present embodiment is an invention based on the following new technical idea, that is, dissociation of a film formation raw material gas (precursor) by remote microwave plasma, which is completely different in principle from catalytic reaction generated based on an activated metal catalyst as in the cited documents 1 and 2, enables formation of a graphene structure having good crystallinity at a relatively low temperature on a substrate that does not have a catalytic function.

[0073] The method for manufacturing a graphene structure of the present embodiment, as shown in Figure 1 includes a step of preparing a processed substrate (step 1), and a step of forming a graphene structure on the surface of the processed substrate by remote microwave plasma CVD in a state in which the surface of the processed substrate does not have a catalytic function (step 2).

[0074] As the processed substrate in step 1, the surface on which the graphene structure is formed can be a semiconductor or an insulator as long as it does not have a catalytic function at the time of remote microwave plasma CVD in step 2. In addition, even if the surface of the processed substrate is metal, as long as the surface of the processed substrate does not have a catalytic function at the time of the remote microwave plasma CVD step without being subjected to activation treatment before the remote microwave plasma CVD step.

[0075] Figure 2 representative examples of the processed substrate. As the processed substrate 300, a semiconductor wafer, for example, can be typically exemplified, such as Figure 2 As shown in (a) of FIG. 3, a processed substrate composed of only a semiconductor substrate 301 of silicon, for example, is exemplified, such as Figure 2 As shown in (b) of FIG. 3, a processed substrate in which an insulating film 302 of SiO2 film, for example, is formed on a semiconductor substrate 301 of silicon, for example, is exemplified, such as Figure 2 As shown in (c) of FIG. 3, a processed substrate in which a metal film 304 of Cu film, for example, is formed on a semiconductor substrate 301 of silicon, for example, through an insulating film 302 of SiO2 film, for example, and a barrier film 303 of TaN film or Ta film, TiN film, or the like. The barrier film 303 can be omitted depending on the metal. In addition, the barrier film 303 can be formed as a stacked film (e.g., Ta / TaN).

[0076] In the formation of the graphene structure in Step 2 based on the remote microwave plasma CVD, the processed substrate is housed in the processing vessel, a microwave is introduced into the processing vessel to generate a microwave plasma, the plasma is diffused toward the processed substrate 300 disposed at a position apart from the plasma generation region, and a carbon-containing gas as a film formation raw material gas, such as Figure 3 is dissociated in the plasma and causes the graphene structure 310 to grow on the processed substrate 300.

[0077] It is preferable to introduce a microwave into the processing vessel and introduce a plasma generation gas composed of a rare gas to generate a microwave plasma, dissociate a carbon-containing gas as a film formation raw material gas in the plasma, and supply the processed substrate 300 apart from the plasma generation region to cause the graphene structure 310 to grow on the processed substrate 300.

[0078] As the rare gas, Ar, He, Ne, Kr, Xe, or the like can be used, of which Ar is preferable in that the plasma can be stably generated.

[0079] As the carbon-containing gas as the film formation raw material gas, ethylene (C2H4), methane (CH4), ethane (C2H6), propane (C3H8), propylene (C3H6), acetylene (C2H2), methanol (CH3OH), ethanol (C2H5OH), or the like can be used. In addition, a hydrogen-containing gas, such as H2 gas, can be introduced together with the carbon-containing gas. The quality of the graphene structure 310 can be improved by the hydrogen-containing gas such as H2 gas.

[0080] The film formation raw material gas can be introduced to a prescribed position between the plasma generation region and the vicinity of the substrate to be processed, according to the desired degree of dissociation. That is, in the plasma generation region, the degree of dissociation is high due to the high-energy plasma, and in the vicinity of the substrate to be processed, the degree of dissociation is lower than in the plasma generation region due to the low-electron-temperature plasma diffused from the plasma generation region, so the degree of dissociation of the film formation raw material gas can be adjusted according to the introduction position of the film formation raw material gas.

[0081] According to the remote microwave plasma CVD, the substrate to be processed is disposed in a region apart from the microwave plasma generation region, and the plasma diffused from the plasma generation region is supplied to the substrate to be processed, so the plasma on the substrate to be processed is low in damage and high in density of radicals due to the microwave. By such a plasma, the carbon-containing gas can be reacted on the surface of the substrate to be processed, and a graphene structure 310 having a good crystallinity can be formed without using the activated metal catalyst layer necessary in the prior art.

[0082] As the graphene structure, not only a general graphene formed parallel to the substrate, but also a CNW grown at an angle with respect to the substrate can be included.

[0083] As the processing conditions at this time, the temperature of the substrate to be processed is 350 to 1000°C, and more preferably 400 to 800°C, and the microwave power is 100 to 5000 W. In addition, the pressure in the processing vessel is preferably 1.33 to 667 Pa (0.01 to 5 Torr) in the case where the surface of the substrate to be processed is an insulator or a semiconductor, and is preferably 1.33 to 400 Pa (0.01 to 3 Torr) in the case where the surface of the substrate to be processed is a metal. This pressure range is shifted to the low-pressure side compared to the ranges in the cited documents 1 and 2, and a low pressure is more advantageous in order to form a graphene structure without providing a catalytic metal layer after activation. In addition, the time is preferably in the range of 1 to 200 min.

[0084] The flow rates of the rare gas, carbon-containing gas, and hydrogen-containing gas suitable for the plasma generation gas can be appropriately set according to the kind of gas and the device to be used.

[0085] Further, before the graphene structure formation by remote microwave CVD in Step 2, surface treatment for the purpose of cleaning the surface of the processed substrate can be performed. As the surface treatment, for example, the processed substrate can be heated to 300 to 600°C, and treatment of supplying, for example, H2gas or Ar gas + H2gas can be performed. Plasma can also be generated at this time. This surface treatment is merely treatment for the purpose of cleaning the surface, and the surface of the processed substrate is not limited to the case of a semiconductor and an insulator, but can also be the case of a metal.

[0086] (Second Embodiment)

[0087] Next, a second embodiment of the graphene structure production method will be described.

[0088] In the present embodiment, a graphene structure containing CNW is formed by remote microwave plasma CVD, similarly to the first embodiment.

[0089] In Patent Documents 1 and 2, graphene is formed on a metal catalytic layer after activation treatment by remote microwave plasma CVD, but CNW is not formed. On the other hand, in the above Patent Document 3, a plasma atmosphere is formed by parallel-plate capacitively coupled plasma (CCP), hydrogen radicals are injected into the plasma atmosphere, and CNW is formed on the surface of the substrate. The growth reaction of CNW occurs in the plasma or in a region where the electron temperature is high, and thus high-energy ions cause damage, and the crystallinity deteriorates.

[0090] Unlike this, the present inventors, in the course of performing experiments of forming a graphene structure by remote microwave plasma CVD without a metal catalytic layer + activation treatment, similarly to the first embodiment, found that under a prescribed low pressure condition, both graphene parallel to the substrate and CNW growing at an angle with respect to the substrate can be formed. In addition, it was found that if the catalytic metal layer is provided and activation treatment is performed under a low pressure condition, CNW is also grown, similarly to the related art.

[0091] The graphene structure production method of the present embodiment, as shown in Figure 4 includes a step of preparing a processed substrate (Step 11), and a step of forming a graphene structure containing CNW on the surface of the processed substrate by remote microwave plasma CVD (Step 12).

[0092] As the processed substrate in Step 11, the surface on which the graphene structure is formed is arbitrary, and the surface can be a semiconductor, an insulator, or a metal. As a specific example of the processed substrate, the processed substrate shown in Figure 2 can be exemplified.

[0093] In the formation of the graphene structure containing CNW in step 12 based on remote microwave plasma CVD, the substrate to be processed is housed in the processing vessel, a microwave is introduced into the processing vessel to generate a microwave plasma, and the plasma is diffused to the substrate to be processed disposed at a position away from the plasma generation region, as shown in FIG. 3. Graphene 321 and CNW 322 are grown on the substrate to be processed 300, and a graphene structure 320 composed of the graphene 321 and the CNW 322 is formed. Figure 5

[0094] Preferably, a microwave is introduced into the processing vessel, and a plasma generation gas formed of a rare gas is introduced to generate a microwave plasma, and a carbon-containing gas as a film formation raw material gas is dissociated by the plasma to be supplied to the substrate to be processed 300 away from the plasma generation region, and a graphene structure 320 composed of the graphene 321 and the CNW 322 is formed on the substrate to be processed 300. At this time, the substrate to be processed surface is a metal catalytic layer, and before the formation of the graphene structure, by performing an activation treatment of the metal catalytic layer, even in a state where the catalytic function is exerted, the CNW can be grown.

[0095] As the plasma generation gas, the film formation raw material gas, that is, the carbon-containing gas, the same gas as in the first embodiment can be used, and a hydrogen-containing gas such as H2 gas can be introduced together with the carbon-containing gas. Also, as in the first embodiment, the film formation raw material gas can be introduced to a prescribed position between the plasma generation region and the vicinity of the substrate to be processed according to the required degree of dissociation.

[0096] Based on remote microwave plasma CVD, the substrate to be processed is disposed in a region away from the microwave plasma generation region, and the plasma diffused from the microwave plasma generation region is supplied to the substrate to be processed, and thus the plasma at a low electron temperature and a high density of radicals as the main body by the microwave is formed on the substrate to be processed. Thus, damage caused by high-energy ions as in Patent Literature 3 does not occur, and a graphene structure containing CNW with good crystallinity can be formed.

[0097] As the processing conditions at this time, the temperature of the substrate to be processed is preferably 350 to 1000°C (more preferably 400 to 800°C), and the microwave power is preferably 100 to 5000 W. Also, the pressure in the processing vessel is preferably 1.33 to 133 Pa (0.01 to 1 Torr). When the pressure is higher than 133 Pa (1 Torr), even if the processing time is increased, the CNW is difficult to grow.

[0098] ​In the case where a metal catalytic layer is provided on the surface of a substrate to be processed and is subjected to an activation treatment, as described in Patent Document 1, as the metal catalytic layer, a metal such as Ni, Co, Cu, Ru, Pt, Pd, or an alloy containing any of them can be exemplified, and as the activation treatment, plasma of a reducing gas such as H2 gas and a nitrogen-containing gas such as N2 gas is generated, and the treatment is performed in a range of 66.7 to 400 Pa (0.5 to 3 Torr) and 300 to 600°C. The time of the plasma CVD is preferably in a range of 1 to 200 min. Since the presence or absence of growth of CNW can be controlled by the time, the treatment time is set to a time in which CNW can grow, according to other treatment conditions than the time.

[0099] The flow rate of a rare gas, a carbon-containing gas, a hydrogen-containing gas, or the like used as a plasma generation gas can be appropriately set according to the kind of the gas and the device used.

[0100] Further, in the present embodiment, before the generation of the graphene structure in step 12 based on the remote microwave CVD, a surface treatment for the purpose of cleaning the surface of the substrate to be processed can be performed as in the first embodiment.

[0101] <Processing device>

[0102] Next, an example of a processing device suitable for the implementation of the formation method of the graphene structure according to the above two embodiments will be described.

[0103] (First example of processing device)

[0104] Figure 6 is a cross-sectional view schematically showing the first example of the processing device. Figure 6 The processing device 100 shown in FIG. 1, for example, is configured as an RLSA (registered trademark) microwave plasma type plasma processing device.

[0105] The processing device 100 includes a substantially cylindrical processing vessel 1, a mounting table 2 provided in the processing vessel 1 to mount a semiconductor wafer (hereinafter simply referred to as "wafer") W, for example, as a substrate to be processed, a microwave introduction mechanism 3 to introduce microwaves into the processing vessel 1, a gas supply mechanism 4 to introduce a gas into the processing vessel 1, an exhaust portion 5 to exhaust the inside of the processing vessel 1, and a control portion 6 to control each of the constituent portions of the processing device 100.

[0106] A circular opening portion 10 is formed in the substantially central portion of the bottom wall la of the processing vessel 1, and an exhaust chamber 11 protruding downward is provided in the bottom wall la so as to communicate with the opening portion 10. A wafer W is introduced into and out of the processing vessel 1 through a side wall thereof via an introduction and discharge port 17, and a gate valve 18 is provided to open and close the introduction and discharge port 17.

[0107] The stage 2 is formed in a circular plate shape by ceramic such as AlN. The stage 2 is supported by a support member 12 which is a cylindrical member formed by ceramic such as AlN and which extends upward from the center of the bottom of the exhaust chamber 11. A guide ring 13 for guiding the wafer W is provided at the outer edge portion of the stage 2. In addition, inside the stage 2, a lift pin (not shown) for lifting the wafer W is provided so as to be able to protrude from or sink into the upper surface of the stage 2. Further, a heater 14 of a resistance heating type is embedded inside the stage 2, and the heater 14 is supplied with power from a heater power source 15 to heat the wafer W on the stage 2 through the stage 2. In addition, a thermocouple (not shown) is inserted into the stage 2, and based on a signal from the thermocouple, the heating temperature of the wafer W can be controlled to a prescribed temperature in the range of, for example, 350 to 1000°C. Further, above the heater 14 in the stage 2, an electrode 16 of substantially the same size as the wafer W is embedded, and the electrode 16 is electrically connected to a high-frequency bias power source 19. The high-frequency bias power source 19 applies a high-frequency bias electric power for introducing ions to the stage 2. Further, the high-frequency bias power source 19 can be set in accordance with the characteristics of the plasma processing.

[0108] The microwave introduction mechanism 3 is provided so as to face the opening portion of the upper portion of the processing vessel 1, and includes a planar slot antenna 21 formed with a large number of slots 21a, a microwave generation portion 22 for generating microwaves, and a microwave transmission mechanism 23 for guiding the microwaves from the microwave generation portion 22 to the planar slot antenna 21. Below the planar slot antenna 21, a microwave transmission plate 24 formed of a dielectric body is provided so as to be supported by a top plate 32 provided in a ring shape at the upper portion of the processing vessel 1, and a shield member 25 of a water cooling structure is provided on the planar slot antenna 21. Further, a slow wave member 26 is provided between the shield member 25 and the planar slot antenna 21.

[0109] The planar slot antenna 21 is, for example, formed of a copper plate or an aluminum plate having a surface plated with silver or gold, and is configured so that a plurality of slots 21a for radiating microwaves are formed so as to pass through in a prescribed pattern. The pattern of the slots 21a is appropriately set so that the microwaves are uniformly radiated. As an example of an appropriate pattern, a radial line slot in which a plurality of pairs of slots 21a are arranged in a concentric circle shape, with two slots 21a arranged in a T shape as one pair, can be given. The length and arrangement interval of the slots 21a can be appropriately set in accordance with the actual effective wavelength (λg) of the microwaves. In addition, the slots 21a can be circular, or can be other shapes such as an arc shape. Further, the arrangement form of the slots 21a is not particularly limited, and can be, for example, a spiral shape or a radial shape in addition to the concentric circle shape. The pattern of the slots 21a is appropriately set so as to become a microwave radiation characteristic which enables a desired plasma density distribution to be obtained.

[0110] The slow wave part 26 is made of a dielectric body having a dielectric constant larger than that of vacuum, such as quartz, ceramic (AI2O3), polytetrafluoroethylene, polyimide, or the like. The slow wave part 26 has a function of making the wavelength of the microwave shorter than in vacuum to reduce the size of the planar slot antenna 21. Further, the microwave transmission plate 24 can also be made of the same dielectric body.

[0111] The thicknesses of the microwave transmission plate 24 and the slow wave part 26 are adjusted in such a manner that the equivalent circuit formed by the slow wave part 26, the planar slot antenna 21, the microwave transmission plate 24, and the plasma satisfies the resonance condition. By adjusting the thickness of the slow wave part 26, the phase of the microwave can be adjusted, and by adjusting the thickness in such a manner that the joint portion of the planar slot antenna 21 becomes an "antinode" of the standing wave, the reflection of the microwave can be minimized and the radiant energy of the microwave can be maximized. In addition, by making the slow wave part 26 and the microwave transmission plate 24 of the same material, the interface reflection of the microwave can be prevented.

[0112] The microwave generation part 22 has a microwave oscillator. The microwave oscillator can be a magnetron oscillator or a solid-state oscillator. The frequency of the microwave oscillated by the microwave oscillator can use a range of 300 MHz to 10 GHz. For example, by using a magnetron as the microwave oscillator, a microwave having a frequency of 2.45 GHz can be oscillated.

[0113] The microwave transmission mechanism 23 includes a waveguide 27 extending in the horizontal direction to transmit the microwave from the microwave generation part 22, a coaxial waveguide 28 composed of an inner conductor 29 extending upward from the center of the planar antenna 21 and an outer conductor 30 outside thereof, and a mode conversion mechanism 31 provided between the waveguide 27 and the coaxial waveguide 28. The microwave generated by the microwave generation part 22 propagates in the waveguide 27 in the TE mode, and the vibration mode of the microwave is converted from the TE mode to the TEM mode by the mode conversion mechanism 31, is guided to the slow wave part 26 via the coaxial waveguide 28, and is radiated into the processing container 1 from the slow wave part 26 via the slot 21a of the planar slot antenna 21 and the microwave transmission plate 24. Further, on the way of the waveguide 27, a tuner (not shown) is provided to match the impedance of the load (plasma) in the processing container 1 with the characteristic impedance of the power source of the microwave generation part 22.

[0114] The gas supply mechanism 4 includes a shower plate 41 provided horizontally in such a manner as to be separated downward at a position above the upper surface of the placement table in the processing container 1, and a shower ring 42 provided in a ring shape along the inner wall of the processing container 1 at a position above the shower plate 41.

[0115] The shower plate 41 includes: a gas flow passage member 51 formed in a lattice shape; a gas flow path 52 provided in the gas flow passage member 51 in a lattice shape; and a large number of gas discharge holes 53 extending downward from the gas flow path 52, with through holes 54 between the lattice-shaped gas flow passage members 51. The gas flow path 52 of the shower plate 41 extends to a gas supply path 55 reaching the outer wall of the processing container 1, and a gas supply pipe 56 is connected to the gas supply path 55. The gas supply pipe 56 is branched into three branch pipes 56a, 56b, 56c, and an H2 gas supply source 57 that supplies H2 gas as a reducing gas, a C2H4 gas supply source 58 that supplies ethylene (C2H4) gas as a film formation raw material gas, and an N2 gas supply source 59 that supplies N2 gas used as a purge gas or the like are connected to the branch pipes 56a, 56b, 56c, respectively. Further, although not shown, a mass flow controller for flow control and valves before and after the same are provided in the branch pipes 56a, 56b, 56c.

[0116] The shower ring 42 includes: a ring-shaped gas flow path 66 provided in the inside thereof; a large number of gas discharge holes 67 that are open in the inner side thereof and are connected to the gas flow path 66, and the gas flow path 66 is connected to a gas supply pipe 61. The gas supply pipe 61 is branched into three branch pipes 61a, 61b, 61c, and an Ar gas supply source 62 that supplies Ar gas as a plasma generation gas, an O2 gas supply source 63 that supplies O2 gas as a cleaning gas, and an N2 gas supply source 64 that supplies N2 gas used as a purge gas or the like are connected to the branch pipes 61a, 61b, 61c, respectively. Further, although not shown, a mass flow controller for flow control and valves before and after the same are provided in the branch pipes 61a, 61b, 61c.

[0117] The exhaust section 5 includes: the above-described exhaust chamber 11; an exhaust pipe 81 provided on the side surface of the exhaust chamber 11; and an exhaust device 82 having a vacuum pump and a pressure control valve or the like connected to the exhaust pipe 81.

[0118] The control section 6 is typically constituted by a computer, and controls each section of the processing device 100. The control section 6 includes a storage section in which a processing flow and a control parameter, i.e., a processing recipe, of the processing device 100 are stored, an input device, a display, and the like, and is capable of performing a prescribed control in accordance with a selected processing recipe.

[0119] With the processing device 100 thus constituted, when forming a graphene structure in accordance with the above-described first embodiment, first, a wafer W formed of, for example, an insulator, a semiconductor, or a metal on the surface thereof is carried into the processing container 1 as a processed substrate, and is placed on the placement table 2, and the surface of the wafer W is cleaned as necessary.

[0120] The preferable conditions of the surface treatment are described below.

[0121] Gas flow rate: Ar / H2= 0-2000 / 10-2000 sccm

[0122] Pressure: 0.1-10 Torr (13.3-1333 Pa)

[0123] Wafer temperature: 300-600°C

[0124] Time: 10-120 min

[0125] Next, the pressure and wafer temperature in the processing vessel 1 are controlled to the prescribed values, and the surface of the wafer W is not catalytically functional (in the case of a metal surface, no activation treatment is performed), and a graphene structure is formed by remote microwave plasma CVD.

[0126] Specifically, Ar gas as a plasma generation gas is supplied from the shower ring 42 to the area directly below the microwave-transmitting plate 24, and the microwave generated by the microwave generation section 22 is guided to the slow wave part 26 via the waveguide 27 of the microwave transmission mechanism 23, the mode conversion mechanism 31, the coaxial waveguide 28, and from the slow wave part 26 to the processing vessel 1 via the slot 21a of the planar slot antenna 21 and the microwave-transmitting plate 24, and the plasma is ignited. The microwave spreads as a surface wave in the area directly below the microwave-transmitting plate 24, and a surface wave plasma generated by the Ar gas is generated, and this area becomes a plasma generation area. Also, at the time when the plasma has been ignited, a film formation raw material gas, C2H4 gas as a carbon-containing gas and H2 gas as needed are supplied from the shower plate 41. These gases are dissociated by the plasma that spreads from the plasma generation area, and are supplied to the wafer W as the substrate to be processed that is placed on the stage 2 below the shower plate 41. Since the wafer W is disposed in an area that is apart from the plasma generation area, the plasma that spreads from the plasma generation area is supplied to the wafer W, and the plasma on the wafer W becomes low in electron temperature, low in damage, and high in density and becomes a radical-dominant plasma. By this plasma, the carbon-containing gas can be made to react on the wafer surface, and a graphene structure with good crystallinity can be formed without using a metal catalytic layer after an activation treatment as required by the prior art.

[0127] At this time, C2H4 gas as a carbon-containing gas and H2 gas as needed are supplied from the shower plate 41 to the area below the plasma generation area, and are dissociated by the plasma that spreads, and thus these gases can be prevented from being excessively dissociated. However, these gases can also be supplied to the plasma generation area. Also, Ar gas as a plasma generation gas can not be used, and C2H4 gas and H2 gas as carbon-containing gases can be supplied to the plasma generation area to directly ignite the plasma.

[0128] Preferred conditions in the remote microwave plasma CVD in the processing apparatus 100 are described below.

[0129] Gas flow rate:

[0130] Ar gas = 0 to 2000 / 10 to 2000 seem

[0131] Hydrogen-carbon gas (C2H4 gas in this case) = 0.1 to 300 seem

[0132] H2 gas = 0.01 to 500 seem

[0133] Pressure:

[0134] When the wafer surface is an insulator and a semiconductor

[0135] 1.33 to 667 Pa (0.01 to 5 Torr)

[0136] When the wafer surface is a metal (without catalytic function)

[0137] 1.33 to 400 Pa (0.01 to 3 Torr)

[0138] Temperature: 350 to 1000°C (more preferably 400 to 800°C)

[0139] Microwave power: 100 to 5000 W (more preferably 1000 to 3500 W)

[0140] Time: 1 to 200 min

[0141] Further, in the case where the method of forming a graphene structure body containing CNW according to the above-described 2nd embodiment is applied, the pressure is preferably in the range of 1.33 to 133 Pa (0.01 to 1 Torr), which is a lower pressure range. In this case, the surface of the wafer W is arbitrary, and a case where a catalytic metal layer is provided on the surface of the wafer W and remote microwave plasma CVD is performed after activation treatment is not excluded. In this case, the activation treatment is preferably performed in the range of pressure: 66.7 to 400 Pa (0.5 to 3 Torr), temperature: 300 to 600°C, H2 gas and N2 gas are supplied at 100 to 2000 seem, respectively, for example, and a microwave with a power of 250 to 4000 W is introduced for 0.5 to 30 min.

[0142] (2nd example of processing apparatus)

[0143] Figure 7 is a cross-sectional view schematically showing the 2nd example of the processing apparatus, Figure 8 is a view showing Figure 7a structural diagram of a structure of a microwave introduction device of a processing device, Figure 9 is a cross-sectional view schematically showing Figure 7 a microwave radiation mechanism of a processing device, Figure 10 is a cross-sectional view schematically showing Figure 7 a top wall portion of a processing container of a processing device.

[0144] The processing device 200 includes a processing container 101 that houses a wafer W, a stage 102 that is disposed inside the processing container 101 and on which the wafer W is placed, a gas supply mechanism 103 that supplies a gas into the processing container 101, an exhaust device 104 that exhausts the processing container 101, a microwave introduction device 105 that generates a microwave for generating plasma in the processing container 101 and introduces the microwave into the processing container 101, and a control section 106.

[0145] The processing container 101 is formed of a metal material such as aluminum and its alloy, for example, and has a substantially cylindrical shape, a plate-shaped top wall portion 111 and a bottom wall portion 113, and a side wall portion 112 that connects them. The microwave introduction device 105 is disposed at an upper portion of the processing container 101 and functions as a plasma generation mechanism that introduces an electromagnetic wave (microwave) into the processing container 101 to generate plasma. The microwave introduction device 105 will be described in detail later.

[0146] The top wall portion 111 has a plurality of opening portions in which a microwave radiation mechanism and a gas introduction portion of the microwave introduction device 105, which will be described later, are embedded. The side wall portion 112 has an in-out port 114 for in-out of a wafer W, which is a processed substrate, between a transport chamber (not shown) adjacent to the processing container 101. The in-out port 114 is opened and closed by a gate valve 115. The exhaust device 104 is disposed at an exhaust pipe 116 connected to the bottom wall portion 113 and has a vacuum pump and a pressure control valve. The processing container 101 is exhausted by the vacuum pump of the exhaust device 104 via the exhaust pipe 116. The pressure in the processing container 101 is controlled by the pressure control valve.

[0147] The stage 102 is formed in a circular plate shape by ceramic such as AlN. The stage 102 is supported by a cylindrical support member 120 formed of ceramic such as AlN, which extends upward from the center of the bottom of the processing container 101. A guide ring 181 for guiding the wafer W is provided at the outer edge portion of the stage 102. In addition, inside the stage 102, a lift pin (not shown) for lifting the wafer W is provided so as to be able to protrude from or sink into the upper surface of the stage 102. Further, a resistance heating type heater 182 is embedded inside the stage 102, and the heater 182 is supplied with power from a heater power source 183, whereby the wafer W on the stage 102 is heated. In addition, a thermocouple (not shown) is inserted into the stage 102. Based on a signal from the thermocouple, the heating temperature of the wafer W can be controlled to a prescribed temperature in the range of, for example, 350 to 1000°C. Further, above the heater 182 in the stage 102, an electrode 184 of substantially the same size as the wafer W is embedded. The electrode 184 is electrically connected to a high-frequency bias power source 122. The high-frequency bias power source 122 applies a high-frequency bias electric power for introducing ions to the stage 102. Note that the high-frequency bias power source 122 can not be provided depending on the characteristics of the plasma processing.

[0148] The gas supply mechanism 103 is a mechanism for introducing a plasma generating gas and a raw material gas for forming a graphene structure into the processing container 101, and has a plurality of gas introduction nozzles 123. The gas introduction nozzles 123 are embedded in the opening portions formed in the top wall portion 111 of the processing container 101. The gas introduction nozzles 123 are connected to a gas supply pipe 191. The gas supply pipe 191 is branched into five branch pipes 191a, 191b, 191c, 191d, and 191e, and the following are connected to each of the branch pipes 191a, 191b, 191c, 191d, and 191e: an Ar gas supply source 192 for supplying an Ar gas, which is a plasma generating gas, as a rare gas; an O2 gas supply source 193 for supplying an O2 gas, which is a cleaning gas, as an oxidizing gas; an N2 gas supply source 194 for supplying an N2 gas, which is used as a purge gas or the like; an H2 gas supply source 195 for supplying an H2 gas, which is a reducing gas; and a C2H4 gas supply source 196 for supplying a C2H4 gas, which is a film forming raw material gas, as a carbon-containing gas. Note that although not shown, a mass flow controller for flow control and valves before and after the mass flow controller are provided in the branch pipes 191a, 191b, 191c, 191d, and 191e. Further, a shower plate is provided as in the first example, and the C2H4 gas and the H2 gas are supplied to a position close to the wafer W, whereby the dissociation of the gases can be adjusted. In addition, the same effect can be obtained by extending the nozzles for supplying these gases downward.

[0149] The microwave introduction device 105 is provided above the processing container 101 as described above, and functions as a plasma generation mechanism that introduces electromagnetic waves (microwaves) into the processing container 101 to generate plasma. As shown in FIG. 1, the microwave introduction device 105 includes a top wall portion 111 of the processing container 101 that functions as a top plate, a microwave output portion 130 that generates microwaves and distributes the microwaves to a plurality of passages to output the microwaves, and an antenna unit 140 that introduces the microwaves output from the microwave output portion 130 into the processing container 101. Figure 7 and Figure 8 As shown in FIG. 1, the microwave introduction device 105 includes a top wall portion 111 of the processing container 101 that functions as a top plate, a microwave output portion 130 that generates microwaves and distributes the microwaves to a plurality of passages to output the microwaves, and an antenna unit 140 that introduces the microwaves output from the microwave output portion 130 into the processing container 101.

[0150] The microwave output portion 130 includes a microwave power source 131, a microwave oscillator 132, an amplifier 133 that amplifies microwaves oscillated by the microwave oscillator 132, and a distributor 134 that distributes the microwaves amplified by the amplifier 133 to a plurality of passages. The microwave oscillator 132 is a solid-state oscillator (solid-state element) that oscillates microwaves at, for example, 860 MHz (for example, PLL oscillation). Furthermore, the frequency of the microwaves is not limited to 860 MHz, and frequencies in the range of 700 MHz to 10 GHz, such as 2.45 GHz, 8.35 GHz, 5.8 GHz, 1.98 GHz, and the like, can be used. The distributor 134 distributes the microwaves while matching the impedances of the input side and the output side.

[0151] The antenna unit 140 includes a plurality of antenna assemblies 141. The plurality of antenna assemblies 141 each introduce the microwaves distributed by the distributor 134 into the processing container 101. The plurality of antenna assemblies 141 are completely identical in configuration. Each antenna assembly 141 includes an amplifier portion 142 that mainly amplifies and outputs the distributed microwaves, and a microwave radiation mechanism 143 that radiates the microwaves output from the amplifier portion 142 into the processing container 101.

[0152] The amplifier portion 142 includes a phase shifter 145 that changes the phase of the microwaves, a variable gain amplifier 146 that adjusts the electric power level of the microwaves input to a main amplifier 147, the main amplifier 147 that is configured as a solid-state amplifier, and a splitter 148 that separates reflected microwaves that are reflected by an antenna portion of the microwave radiation mechanism 143 described below toward the main amplifier 147.

[0153] As shown in FIG. 1, the microwave introduction device 105 includes a top wall portion 111 of the processing container 101 that functions as a top plate, a microwave output portion 130 that generates microwaves and distributes the microwaves to a plurality of passages to output the microwaves, and an antenna unit 140 that introduces the microwaves output from the microwave output portion 130 into the processing container 101. Figure 7 As shown in FIG. 1, the microwave introduction device 105 includes a top wall portion 111 of the processing container 101 that functions as a top plate, a microwave output portion 130 that generates microwaves and distributes the microwaves to a plurality of passages to output the microwaves, and an antenna unit 140 that introduces the microwaves output from the microwave output portion 130 into the processing container 101. Figure 9As shown, it includes an outer conductor 152 formed in a cylindrical shape and an inner conductor 153 disposed coaxially with the outer conductor 152 inside the outer conductor 152, and includes a coaxial tube 151 having a microwave propagation path therebetween; a supply portion 155 that supplies the microwave amplified by the amplifier portion 142 to the microwave propagation path; a tuner 154 that matches the impedance of the load to the characteristic impedance of the microwave power source 131; and an antenna portion 156 that radiates the microwave from the coaxial tube 151 into the processing vessel 101.

[0154] The supply portion 155 introduces the microwave amplified by the amplifier portion 142 from the side of the upper end portion of the outer conductor 152 through a coaxial cable, for example, radiates the microwave through a supply antenna, thereby supplying the microwave power to the microwave propagation path between the outer conductor 152 and the inner conductor 153, and the microwave power propagates to the antenna portion 156.

[0155] The antenna portion 156 is provided at the lower end portion of the coaxial tube 151. The antenna portion 156 includes a planar antenna 161 formed in a circular plate shape connected to the lower end portion of the inner conductor 153; a slow wave member 162 disposed on the upper surface side of the planar antenna 161; and a microwave transmission plate 163 disposed on the lower surface side of the planar antenna 161. The microwave transmission plate 163 is embedded in the top wall portion 111, and the lower surface thereof is exposed to the inside space of the processing vessel 101. The planar antenna 161 has a groove 161a formed in a through manner. The shape of the groove 161a is appropriately set in a manner that the microwave can be efficiently radiated. A dielectric body can be inserted in the groove 161a. The slow wave member 162 is formed of a material having a dielectric constant larger than that of vacuum, and the phase of the microwave can be adjusted by the thickness thereof, and the radiant energy of the microwave can be maximized. The microwave transmission plate 163 can also be composed of a dielectric body, and is formed in a shape that can efficiently radiate the microwave in a TE mode. Furthermore, the microwave that has passed through the microwave transmission plate 163 generates plasma in the space inside the processing vessel 101. As the material constituting the slow wave member 162 and the microwave transmission plate 163, for example, quartz or ceramic, a fluorine-based resin such as polytetrafluoroethylene resin, a polyimide resin, or the like can be used.

[0156] The tuner 154 constitutes a slug tuner, as shown in Figure 9 includes two cores 171a, 171b disposed at a portion of the coaxial tube 151 on the proximal end portion side (upper end portion side) than the antenna portion 156; an actuator 172 that independently drives the two cores; and a tuner controller 173 that controls the actuator 172.

[0157] Iron cores 171a and 171b are formed in a plate-like and ring-like shape, and are made of a dielectric material such as ceramic. They are disposed between the outer conductor 152 and the inner conductor 153 of the coaxial tube 151. Furthermore, the actuator 172 rotates, for example, two screws located inside the inner conductor 153 and screwed (engaged) onto the iron cores 171a and 171b, thereby driving the iron cores 171a and 171b respectively. Based on commands from the tuner controller 173, the actuator 172 moves the iron cores 171a and 171b in the vertical direction. The tuner controller 173 adjusts the position of the iron cores 171a and 171b so that the impedance at the terminal end becomes 50Ω.

[0158] The main amplifier 147, tuner 154, and planar antenna 161 are arranged close to each other. Furthermore, the tuner 154 and planar antenna 161 form a lumped constant circuit and function as a resonator. While there is impedance mismatch in the mounting section of the planar antenna 161, it is directly tuned to the plasma load via the tuner 154, thus enabling high-precision tuning including the plasma and eliminating the effects of reflections in the planar antenna 161.

[0159] like Figure 10 As shown, in this example, seven microwave radiating mechanisms 143 are provided, and the corresponding microwave transmission plates 163 are arranged in a uniform hexagonal close-packed configuration. That is, one of the seven microwave transmission plates 163 is located in the center of the top wall portion 111, and the other six microwave transmission plates 163 are arranged around it. These seven microwave transmission plates 163 are arranged such that adjacent microwave transmission plates are equally spaced. In addition, the plurality of nozzles 123 of the gas supply mechanism 103 are arranged to surround the central microwave transmission plate. Furthermore, the number of microwave radiating mechanisms 143 is not limited to seven.

[0160] The control unit 106 is typically composed of a computer and controls various parts of the processing device 200. The control unit 106 includes a storage unit that stores a processing scheme that serves as the processing flow and control parameters of the processing device 200, an input device, and a display, and performs prescribed control according to the selected processing scheme.

[0161] When forming a graphene structure according to the first embodiment described above using the processing apparatus 200 configured in this way, firstly, a wafer W, whose surface is made of, for example, an insulator, a semiconductor, or a metal, is fed into the processing substrate, placed on the stage 102, and the surface of the wafer W is cleaned as needed.

[0162] The preferred conditions for this surface treatment are described below.

[0163] Gas flow rate: Ar / H2= 0-2000 / 10-2000 sccm

[0164] Pressure: 0.1-10 Torr (13.3-1333 Pa)

[0165] Wafer temperature: 300-600°C

[0166] Time: 10-120 min

[0167] Next, the pressure and wafer temperature in the processing vessel 101 are controlled to prescribed values, and a graphene structure is formed by remote microwave plasma CVD in a state in which the surface of the wafer W does not have catalytic function (no activation treatment is performed in the case of a metal surface).

[0168] Specifically, Ar gas as a plasma generation gas is supplied from the gas introduction nozzle 123 to the directly below the top wall portion 111 of the processing vessel 101, and the plurality of antenna assemblies 141 of the microwave introduction antenna unit 140, which are distributed from the microwave output portion 130 of the microwave introduction device 105, are caused to radiate from the microwave radiating mechanisms 143, and plasma is ignited.

[0169] In each of the antenna assemblies 141, the microwaves are respectively amplified by the main amplifiers 147 constituting the solid-state amplifiers, are supplied to each of the microwave radiating mechanisms 143, propagate in the coaxial tubes 151, and reach the antenna portions 156. At this time, the microwaves are automatically matched in impedance by the cores 171a and 171b of the tuners 154, are radiated from the grooves 161a of the planar antennas 161 via the slow wave members 162 of the tuners 154 in a state in which there is substantially no reflection of electric power, further pass through the microwave transmission plate 163, propagate on the surface (lower surface) of the microwave transmission plate 163 in contact with the plasma, and form a surface wave. Furthermore, the electric power from each of the antenna portions 156 is spatially synthesized in the processing vessel 101, and a surface wave plasma based on the Ar gas is generated in the region directly below the top wall portion 111, and this region becomes a plasma generation region.

[0170] Then, at the time when the plasma has been ignited, a film forming raw material gas, i.e., C2H4 gas as a carbon-containing gas and H2 gas as needed are supplied from the gas introduction nozzle 123. These gases are dissociated by the plasma and supplied to the wafer W as a processed substrate placed on the placement table 102. Since the wafer W is disposed in a region apart from the plasma generation region, the plasma diffused from the plasma generation region is supplied to the wafer W, and thus the plasma on the wafer W becomes low in electron temperature, low in damage, and high in density of radicals. By such a plasma, the carbon-containing gas can be caused to react on the wafer surface, and a graphene structure with good crystallinity can be formed without using a metal catalyst layer after activation treatment, which is necessary in the prior art.

[0171] In this example, C2H4 gas as a carbon-containing gas and H2 gas as needed are supplied to the plasma generation region and dissociated, and the dissociation of C2H4 gas and H2 gas as needed by the plasma diffused from the plasma generation region can also be suppressed using the same shower plate as in the first example or by extending the gas introduction nozzle. In addition, C2H4 gas and H2 gas as a carbon-containing gas can be supplied to the plasma generation region without using Ar gas as a plasma generation gas to ignite the plasma directly.

[0172] In the processing apparatus 200 of this example, the microwaves divided into a plurality of microwaves are respectively amplified by the main amplifier 147 constituting a solid-state amplifier, and after being introduced into the processing vessel 101 from the plurality of antenna sections 156 to form surface waves, they are combined in space to generate microwave plasma, and thus a large separator and combiner are not necessary, and the processing apparatus 200 is small (compact). Further, the main amplifier 147, the tuner 154, and the planar antenna 161 are disposed close to each other, the tuner 154 and the planar antenna 161 constitute a lumped constant circuit, and function as a resonator, and thus in the planar slot antenna mounting section where there is impedance mismatch, the tuning including the plasma can be performed with high precision by the tuner 154, and thus the influence of reflection can be reliably eliminated, and high-precision plasma control can be achieved. In addition, since a plurality of microwave transmission plates 163 are provided, the total area can be reduced compared to the single microwave transmission plate 24 in the processing apparatus of the first example, and the power of microwaves necessary for igniting and discharging the plasma stably can be reduced.

[0173] The preferable conditions in the remote microwave plasma CVD in the processing apparatus 200 are basically the same as in the first example, but the more preferable conditions differ depending on the item, as described below.

[0174] Gas flow rate:

[0175] Ar gas = 0 to 2000 / 10 to 2000 seem

[0176] hydrogen-carbon gas (C2H4 gas in this case) = 0.1 to 300 seem

[0177] H2 gas = 0.01 to 500 seem

[0178] Pressure:

[0179] In the case where the surface of the wafer W is an insulator and a semiconductor

[0180] 1.33 to 667 Pa (0.01 to 5 Torr)

[0181] In the case where the surface of the wafer W is a metal (without catalytic function)

[0182] 1.33 to 400 Pa (0.01 to 3 Torr)

[0183] Temperature: 350 to 1000°C (more preferably 400 to 800°C)

[0184] Microwave power: 100 to 5000 W in total (more preferably 1000 to 3500 W)

[0185] Time: 1 to 200 min.

[0186] Further, in the case where the method of forming a graphene structure body containing CNW according to the above-described 2nd embodiment is applied in the apparatus of this example, the pressure is preferably in the range of 1.33 to 133 Pa (0.01 to 133 Torr), which is a range of even lower pressure. In this case, the surface of the wafer W is arbitrary, and the case where a catalytic metal layer is provided on the surface of the wafer W and remote microwave plasma CVD is performed after activation treatment is not excluded. In this case, the activation treatment is performed in the same manner as in the 1st example, in the range of pressure: 66.7 to 400 Pa (0.5 to 3 Torr), temperature: 300 to 600°C, H2 gas and N2 gas are supplied at 100 to 2000 seem each, for example, and a microwave with a total power of 250 to 4000 W is introduced, and the treatment is performed for 0.5 to 30 min.

[0187] [Other applications]

[0188] The embodiments of the present application have been described above, but the present application is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea of the present application.

[0189] For example, the processing apparatus used for performing remote microwave plasma CVD in the above-described embodiments is merely an example, and various types of processing apparatuses can be used.

[0190] Further, as the substrate to be processed for forming the graphene structure, a semiconductor wafer having a semiconductor substrate such as Si as a base is exemplified, but is not limited thereto.

[0191]

EXAMPLE

[0192] Hereinafter, an example of the present application will be described.

[0193] (Example 1)

[0194] Here, as the substrate to be processed, a wafer having a SiO2 film formed on a Si substrate (without a catalytic metal layer) was prepared, and remote microwave plasma CVD was performed using the processing apparatus of Example 1 under conditions of Ar gas flow rate: 500 seem, C2H4 gas flow rate: 20 seem, pressure: 0.05 Torr, temperature: 530°C, microwave power: 2 kW, and time: 20 min. The SEM photograph at this time is shown in FIG. 6. As shown in the SEM photograph, it was confirmed that a graphene structure including graphene and CNW could be grown on the wafer having an insulator formed on the surface without using a catalyst. The Raman spectrum at this time is shown in FIG. 7. As shown in the graph, a Raman signal from graphene could be confirmed. The value of the ratio of G band to D band (G / D ratio) as an index of crystallinity was 0.44. This value was higher than the value of G / D ratio of 0.35 described in the above-mentioned Patent Document 3, and it was confirmed that CNW having good crystallinity was grown. Figure 11 Figure 12

[0195] (Example 2)

[0196] Here, as the substrate to be processed, a wafer having a SiO2 film formed on a Si substrate (without a catalytic metal layer) was prepared, and remote microwave plasma CVD was performed using the processing apparatus of Example 1 under conditions of Ar gas flow rate: 500 seem, C2H4 gas flow rate: 20 seem, pressure: 0.05 Torr, temperature: 530°C, microwave power: 2 kW, and time: 20 min. The SEM photograph at this time is shown in FIG. 6. As shown in the SEM photograph, it was confirmed that a graphene structure including graphene and CNW could be grown on the wafer having an insulator formed on the surface without using a catalyst. The Raman spectrum at this time is shown in FIG. 7. As shown in the graph, a Raman signal from graphene could be confirmed. The value of the ratio of G band to D band (G / D ratio) as an index of crystallinity was 0.44. This value was higher than the value of G / D ratio of 0.35 described in the above-mentioned Patent Document 3, and it was confirmed that CNW having good crystallinity was grown. Figure 13 ​​As shown in the figure, a graphene structure comprising graphene and CNW was grown on a wafer, with the CNW having a thickness of approximately 740 nm. This confirms that the growth rate of the CNW is greater than 2 μm / h. In the aforementioned literature, the CNW growth rate was approximately 1.5 μm / h, confirming that CNWs can be formed at a higher growth rate than existing technologies.

[0197] (Example 3)

[0198] Here, as the substrate to be processed, a wafer (without a catalytic metal layer) with a SiO2 film formed on a Si substrate was prepared, similar to that in Example 1. Using the processing apparatus of Example 1, remote microwave plasma CVD processing was performed under the following conditions: Ar gas flow rate: 500 sccm, C2H4 gas flow rate: 20 sccm, pressure: 0.05 Torr, temperature: 530°C, microwave power: 2 kW, and time: 20 min. The TEM image at this time is shown below. Figure 14 , 15 middle.

[0199] Figure 14 (a) indicates that a graphene structure has been grown on the wafer. Figure 14 (b) magnified to show the CNW in the graphene structure. Figure 14 (c) and (d) are further enlarged representations. Figure 14 Regions A and B of (b). Figure 14 As shown, graphene and CNW were grown as graphene structures, with the CNW formed from multiple layers of graphene sheets. Furthermore, it can be confirmed that step edges exist on the graphene sheets constituting the CNW.

[0200] Figure 15 (a) indicates that a graphene structure has been grown on the wafer. Figure 15 (b) is an enlarged representation of the graphene and CNW portions of the graphene structure. Figure 15 (c) and (d) are further enlarged representations. Figure 15 Regions C and D of (b). Figure 15 As shown, graphene is generated on the wafer, and CNW is grown from the branching of graphene.

[0201] (Example 4)

[0202] Here, the processing conditions were changed, and the configuration of the grown graphene structure was confirmed. As with Example 1, as the substrate to be processed, a wafer on which a SiO2 film was formed on a Si substrate (without a catalytic metal layer) was prepared, and remote microwave plasma CVD was performed using the processing apparatus of Example 1, with the processing conditions (Condition 1) of Ar gas flow rate: 500 seem, C2H4 gas flow rate: 20 seem, pressure: 0.05 Torr, temperature: 530°C, microwave power: 2 kW, time: 20 min; and the processing conditions (Condition 2) of Ar gas flow rate: 500 seem, C2H4 gas flow rate: 20 seem, pressure: 0.08 Torr, temperature: 530°C, microwave power: 2 kW, time: 80 min.

[0203] Figure 16 (a) of FIG. 10 is an SEM photograph at this time. According to this SEM photograph, graphene and CNWs were grown as graphene structures. Figure 16 (b) of FIG. 10 is a TEM photograph of the CNWs included in the graphene structure, and it was found that a plurality of graphene sheets were formed. In addition, Figure 16 (b) of FIG. 10 is a TEM photograph of the CNWs included in the graphene structure, and it was found that a plurality of graphene sheets were formed. In addition, Figure 16 (c) of FIG. 10 is a Raman spectrum of the CNWs, and a Raman signal from graphene could be confirmed.

[0204] On the other hand, Figure 17 (a) of FIG. 12 is an SEM photograph at this time. According to this SEM photograph, only graphene was grown as a graphene structure. Figure 17 (b) of FIG. 12 is a TEM photograph of the graphene structure, and a plurality of graphene sheets were stacked in parallel with the wafer at a thickness of 10 nm. In addition, Figure 17 (b) of FIG. 12 is a TEM photograph of the graphene structure, and a plurality of graphene sheets were stacked in parallel with the wafer at a thickness of 10 nm. In addition, Figure 17 (c) of FIG. 12 is a Raman spectrum of the graphene structure, and a Raman signal from graphene could be confirmed.

[0205] According to the above, it was confirmed that CNWs were grown by process adjustment, and that CNW growth was suppressed and only graphene could be grown.

[0206] (Example 5)

[0207] Here, as the substrate to be processed, a Si wafer (without a catalytic metal layer) was prepared, and remote microwave plasma CVD processing was performed using the processing apparatus of Example 1, with the conditions of Ar gas flow rate: 500 seem, C2H4 gas flow rate: 20 seem, pressure: 0.05 Torr, temperature: 530°C, microwave power: 2 kW, time: 20 min. The SEM photograph at this time is shown in Figure 18In this case, as the substrate to be processed, a wafer on which a SiO2 film, a TaN film, a Ta film, and a Cu film were sequentially formed on a Si substrate was prepared, and a remote microwave plasma CVD process was performed using the processing apparatus of Example 1 without performing the activation process, under conditions of Ar gas flow rate: 500 seem, C2H4 gas flow rate: 20 seem, pressure: 0.02 Torr, temperature: 510°C, microwave power: 2 kW, and time: 20 min. The SEM photograph at this time is shown in

[0208] (Example 6)

[0209] In this case, as the substrate to be processed, a wafer on which a SiO2 film, a TaN film, a Ta film, and a Cu film were sequentially formed on a Si substrate was prepared, and a remote microwave plasma CVD process was performed using the processing apparatus of Example 1 without performing the activation process, under conditions of Ar gas flow rate: 500 seem, C2H4 gas flow rate: 20 seem, pressure: 0.02 Torr, temperature: 510°C, microwave power: 2 kW, and time: 20 min. The SEM photograph at this time is shown in Figure 19

[0210] (Example 7)

[0211] In this case, the pressure was changed, and the state of the grown graphene structure was confirmed. The results are shown in the SEM photographs of Figure 20 Figure 20 (a) of FIG. 20 is a case where the pressure was 20 mTorr (plasma ignition lower limit pressure), Figure 20 (b) of FIG. 20 is a case where the pressure was 70 mTorr, Figure 20 (c) of FIG. 20 is a case where the pressure was 100 mTorr, Figure 20 (d) of FIG. 20 is a case where the pressure was 5 Torr. Further, as the substrate to be processed, (a) was the same as in Example 6, that is, the wafer on which the Cu film was formed on the Si substrate, (b) to (c) were wafers on which a SiO2 film was formed on a Si substrate (without a catalytic metal layer). In addition, as the other conditions, in (a) and (b), the Ar gas flow rate was 500 seem, the C2H4 gas flow rate was 20 seem, the temperature was 510°C, the microwave power was 2 kW, and the time was 20 min, in (c), the Ar gas flow rate was 2000 seem, the C2H4 gas flow rate was 1 to 10 seem, the temperature was 530°C, the microwave power was 2 kW, and the time was 20 min, and in (d), the Ar gas flow rate was 2000 seem, the C2H4 gas flow rate was 1 to 10 seem, the temperature was 580°C, the microwave power was 2 kW, and the time was 80 min.

[0212] As shown in the SEM photograph of Figure 20 ​​As shown, it was confirmed that graphene structures could grow within a pressure range of 20 mTorr to 5 Torr, although the density and morphology changed. Furthermore, it was confirmed that CNW grew up to a pressure of 70 mTorr, but at a pressure of 100 mTorr, only graphene grew.

[0213] (Example 8)

[0214] Here, remote microwave plasma CVD processing was performed using temperature variations. The Raman spectrum at this point is represented as follows: Figure 21 In addition, here, as the substrate to be processed, a wafer with a SiO2 film formed on a Si substrate (without a catalytic metal layer) is prepared, and other conditions are: Ar gas flow rate: 50 sccm, C2H2 gas flow rate: 1 sccm, pressure: 0.4 Torr, microwave power: 425 W, and time: 10 min. Figure 21 As shown, Raman signals from graphene were confirmed at temperatures ranging from 350 to 750 °C (the upper limit of wafer temperature).

[0215] (Example 9)

[0216] Here, a Si wafer (without a catalyst metal layer) was prepared as the substrate to be processed. Using the processing apparatus of Example 2, a pretreatment (surface treatment) was performed with Ar gas: 300 sccm, H2 gas: 50 sccm, pressure: 1 Torr, temperature: 700°C, total microwave power: 300 W, and time: 10 min. Then, remote microwave plasma CVD processing was performed under the following conditions: Ar gas flow rate: 50 sccm, C2H2 gas flow rate: 1 sccm, pressure: 0.4 Torr, temperature: 700°C, total microwave power: 425 W, and time: 10 min. The SEM image at this time shows... Figure 22 As shown in the SEM image, it can be confirmed that graphene structures, including graphene and CNW, were grown on a Si wafer, which serves as a semiconductor, without a catalyst. The Raman spectrum at this point indicates... Figure 23 As shown in the figure, the Raman signal from graphene was confirmed.

Claims

1. A method for forming a graphene structure, characterized in that, include: Steps for preparing the substrate to be processed; and The step involves forming a graphene structure on the surface of the substrate being treated by remote microwave plasma CVD using a carbon-containing gas as the film-forming raw material gas, in a state where the surface of the substrate does not have catalytic function. The step of forming the graphene structure is performed by a processing device, which includes: A processing container for containing the substrate being processed; A stage within the processing container on which the substrate to be processed is horizontally placed; A heating mechanism for heating the substrate being processed; Microwave induction device disposed on the processing container; A gas introduction mechanism that supplies a carbon-containing gas, used as a film-forming material, into the processing container; and An exhaust mechanism for venting air from the processing container. The microwave induction device includes: A microwave generating unit for generating microwaves; and Multiple microwave radiating mechanisms, supplied with microwaves distributed from the microwave generating unit, radiate microwaves into the processing container. The microwave radiation mechanism includes: Tuner used for impedance matching; A planar slot antenna with a slot that radiates microwaves supplied by the antenna; and A microwave transmission plate made of dielectric material is disposed adjacent to the planar slot antenna and embedded in the top wall of the processing container. The gas introduction mechanism supplies a rare gas, which serves as a plasma generating gas, to the region directly below the top wall of the processing container, and supplies a carbon-containing gas, which serves as the film-forming raw material gas, to a predetermined position between the top wall and the substrate being processed on the mounting stage. In the step of forming the graphene structure, the substrate to be treated is positioned in a region away from the plasma generation region where microwave plasma is generated. A carbon-containing gas, serving as the film-forming raw material gas, is supplied to a predetermined location between the plasma generation region and a nearby region of the substrate to be treated, based on the required degree of dissociation of the film-forming raw material gas, and dissociated therefrom. The dissociated film-forming raw material gas is then supplied to the substrate to be treated. In the step of forming the graphene structure, the graphene structure consists only of graphene formed parallel to the substrate being treated. In the step of forming the graphene structure, the pressure inside the processing container is 1.33 to 667 Pa when the surface of the substrate being processed is an insulator or a semiconductor, and 1.33 to 400 Pa when the surface of the substrate being processed is a metal.

2. The method for forming a graphene structure as described in claim 1, characterized in that: The surface of the substrate being processed is an insulator or a semiconductor.

3. The method for forming a graphene structure as described in claim 1, characterized in that: The surface of the substrate being processed is metallic and does not undergo activation treatment.

4. The method for forming a graphene structure as described in claim 1, characterized in that: The step of forming the graphene structure is carried out under the following conditions: the temperature of the substrate being treated is in the range of 350 to 1000°C, the microwave power is in the range of 100 to 5000W, and the time is in the range of 1 to 200 minutes.

5. A graphene structure forming apparatus for forming graphene structures, characterized in that, include: A processing container used to house the substrate being processed; A stage within the processing container on which the substrate to be processed is horizontally placed; A heating mechanism for heating the substrate being processed; Microwave induction device disposed on the processing container; A gas introduction mechanism supplies a gas, including carbon-containing gas, as a film-forming material into the processing container; An exhaust mechanism for venting air from the processing container; and A control unit that controls the heating mechanism, the microwave inlet device, the gas inlet mechanism, and the exhaust mechanism. The microwave induction device includes: A microwave generating unit for generating microwaves; and Multiple microwave radiating mechanisms, supplied with microwaves distributed from the microwave generating unit, radiate microwaves into the processing container. The microwave radiation mechanism includes: A tuner for impedance matching; A planar slot antenna with a slot that radiates microwaves supplied by the antenna; and A microwave transmission plate made of dielectric material is disposed adjacent to the planar slot antenna and embedded in the top wall of the processing container. The gas introduction mechanism supplies a rare gas, which serves as a plasma generating gas, to the region directly below the top wall of the processing container, and supplies a carbon-containing gas, which serves as the film-forming raw material gas, to a predetermined position between the top wall and the substrate being processed on the mounting stage. The control unit controls the heating mechanism, the microwave introduction device, the gas introduction mechanism, and the exhaust mechanism to perform a method for forming a graphene structure, the method comprising: The steps for preparing the substrate to be processed; and The step involves forming a graphene structure on the surface of the substrate being treated by remote microwave plasma CVD using a carbon-containing gas as the film-forming raw material gas, in a state where the surface of the substrate does not have catalytic function. In the step of forming the graphene structure, the substrate to be treated is positioned in a region away from the plasma generation region where microwave plasma is generated. A carbon-containing gas, serving as the film-forming raw material gas, is supplied to a predetermined location between the plasma generation region and a nearby region of the substrate to be treated, based on the required degree of dissociation of the film-forming raw material gas, and dissociated therefrom. The dissociated film-forming raw material gas is then supplied to the substrate to be treated. In the step of forming the graphene structure, the graphene structure consists only of graphene formed parallel to the substrate being treated. In the step of forming the graphene structure, the pressure inside the processing container is 1.33 to 667 Pa when the surface of the substrate being processed is an insulator or a semiconductor, and 1.33 to 400 Pa when the surface of the substrate being processed is a metal.

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