Film deposition method and plasma treatment apparatus

Abstract

To allow deposition of graphene on a substrate even with plasma generated by electric power with a frequency of a VHF band or lower.SOLUTION: A film deposition method includes Step a) and Step b). In Step a), a substrate can be mounted, a stage connected to the ground through a first electrical path is arranged inside, a conductive ring member connected to the ground through a second electrical path is arranged in a periphery of the stage, and the substrate is mounted on the stage inside a treatment container in which an electrode is arranged facing the stage. In Step b), plasma is generated in the treatment container by supplying electrical power with a frequency of VHF (Very High Frequency) or lower in a state where an impedance of the first electrical path is higher than that of the second electrical path while a treatment gas containing a carbon-containing gas is supplied into the treatment container, and graphene is deposited on the substrate.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a film forming method and a plasma processing apparatus. [Background technology]

[0002] Patent Document 1 listed below discloses "a pretreatment method carried out before growing graphene by a CVD method on a catalytic metal layer formed on a substrate, the pretreatment method comprising a plasma treatment step of activating the catalytic metal layer by applying plasma of a treatment gas containing a reducing gas and a nitrogen-containing gas to the catalytic metal layer." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-100205 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique that enables graphene to be formed on a substrate even with plasma generated by power with a frequency below the VHF (Very High Frequency) band. [Means for solving the problem]

[0005] A film forming method according to an embodiment of the present disclosure includes steps a) and b). In step a), a substrate is placed on a stage inside a processing vessel in which a stage on which a substrate can be placed and which is connected to ground via a first electrical path is disposed, a conductive ring member connected to ground via a second electrical path is disposed around the stage, and an electrode is disposed opposite the stage. In step b), while supplying a processing gas including a carbon-containing gas into the processing vessel, the impedance of the first electrical path is made higher than the impedance of the second electrical path, and power having a frequency equal to or lower than a VHF (Very High Frequency) band is supplied to the electrode to generate plasma in the processing vessel, and graphene is formed on the substrate. Effect of the Invention

[0006] According to the present disclosure, it is possible to form a graphene film on a substrate even with plasma generated by power with a frequency below the VHF band. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration of a plasma processing apparatus 1 according to an embodiment. [Diagram 2] FIG. 2 is a diagram showing a schematic example of a flow of high-frequency power according to the embodiment. [Figure 3A] FIG. 3A shows the ion energy distribution for the first experiment. [Figure 3B] FIG. 3B shows the ion energy distribution for the first experiment. [Figure 4] FIG. 4 is a flowchart showing an example of a film forming method according to this embodiment. [Diagram 5] FIG. 5 shows a Raman spectrum of the substrate on which the graphene film was formed in the second experiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, embodiments of a film forming method and a plasma processing apparatus will be described in detail with reference to the drawings. Note that the film forming method and the plasma processing apparatus disclosed below are not limited to the following embodiments.

[0009] Conventionally, for example, a technique is known in which a microwave is introduced into a chamber to generate plasma and form a graphene film on a substrate. For example, a microwave of 860 MHz is used to generate the plasma.

[0010] In order to improve the productivity of graphene film formation, a multi-wafer type film formation device is required. However, it is difficult to form a multi-wafer film with a film formation device that generates plasma using microwaves. For multi-wafer formation, a plasma processing device that generates plasma using power in the VHF band or a frequency lower than the VHF band is preferable. The VHF band is a frequency range of 30 to 300 MHz.

[0011] However, plasma generated by power with frequencies below the VHF band (30 MHz or less) has high ion energy, making it difficult to deposit continuous graphene films by ion bombardment. Therefore, there is hope for a technology that will enable graphene to be deposited on substrates even with plasma generated by power with frequencies below the VHF band.

[0012] (Embodiment) (Configuration of Plasma Processing Apparatus) Next, an embodiment will be described. FIG. 1 is a diagram that shows a schematic diagram of a plasma processing apparatus 1 according to an embodiment. The plasma processing apparatus 1 shown in FIG. 1 includes a chamber 10. The chamber 10 provides an internal space therein. The chamber 10 may include a chamber body 12. The chamber body 12 has a substantially cylindrical shape. Walls of the chamber 10, including a side wall 12a and a bottom wall 12b, are provided by the chamber body 12. The internal space of the chamber 10 is provided in the chamber body 12. The chamber body 12 is formed of a conductive metal such as aluminum. The chamber body 12 is grounded via a wiring 13. In the embodiment, the chamber 10 corresponds to a processing vessel of the present disclosure.

[0013] The plasma processing apparatus 1 further includes a substrate support 14. The substrate support 14 is provided in the chamber 10. The substrate support 14 is configured to support a substrate W placed thereon. The substrate support 14 has a main body. The main body of the substrate support 14 is formed of, for example, aluminum nitride, and may have a disk shape. In the embodiment, the substrate support 14 corresponds to a stage of the present disclosure.

[0014] The substrate support 14 is supported by a support member 16. The support member 16 is formed in a cylindrical shape. An opening 12c is formed near the center of the bottom wall 12b of the chamber 10. The substrate support 14 passes through the opening 12c and is connected to a flange 25 below the bottom wall 12b. The flange 25 is formed to be wider and flatter than the opening 12c. The flange 25 can be raised and lowered by a lifting mechanism 26. When the flange 25 is raised and lowered, the support member 16 and the substrate support 14 are raised and lowered together with the flange 25. When the substrate support 14 is raised and lowered, the distance between the substrate W placed on the substrate support 14 and the upper electrode 30 described later is changed. The lifting mechanism 26 is controlled by a control unit 80 described later.

[0015] The bottom wall 12b of the chamber 10 and the flange 25 are connected via a bellows 27. This maintains airtightness inside the chamber 10 even when the flange 25 is raised and lowered by the lifting mechanism 26. The substrate support 14 is electrically isolated from the chamber 10. In one embodiment, the substrate support 14 is electrically isolated from the chamber 10 by connecting at least one of the substrate support 14 and the support member 16, and the support member 16 and the flange 25 via an insulating member.

[0016] The substrate support 14 can be raised and lowered within the chamber 10 by an elevating mechanism 26 via a flange 25 and a support member 16. Fig. 1 shows the substrate support 14 in a raised state.

[0017] When loading and unloading the substrate W, the substrate support 14 is lowered by the lifting mechanism 26 to a transfer position where the substrate W can be loaded and unloaded. A load / unload port (not shown) is formed in the side wall 12a of the chamber 10 at a position approximately the same height as the transfer position. The load / unload port can be opened and closed by a gate valve. The substrate W is loaded into the chamber 10 through the load / unload port (not shown) by a transfer mechanism such as a transfer arm, and placed on the substrate support 14 that has been lowered to the transfer position.

[0018] When processing the substrate W, the substrate support part 14 is raised by the lifting mechanism 26. When performing a film formation process on the substrate W, the height of the substrate support part 14 is adjusted to a processing position where a distance between the upper surface of the substrate support part 14 and the lower surface of an upper electrode 30 (described later) is a predetermined distance. The predetermined distance is determined by the film formation conditions.

[0019] The substrate support 14 includes a lower electrode 18. The lower electrode 18 is formed of a conductive metal such as aluminum, and is embedded in the body of the substrate support 14. The substrate support 14 may have a heater 20. The heater 20 is embedded in the body of the substrate support 14. The heater 20 is a resistive heating element, and is formed of a high melting point metal such as molybdenum. The heater 20 is connected to a heater power source 22 via wiring 28b provided inside the substrate support 14, the support member 16, and the flange 25. The heater power source 22 is provided outside the chamber 10. The heater 20 receives power from the heater power source 22 and generates heat to heat the substrate W. The substrate support 14 may be entirely formed of a conductive metal such as aluminum, and the entire substrate support 14 may function as the lower electrode 18. In this case, a cover ring is provided on the substrate support 14 so as to cover the upper surface and side surfaces. The cover ring is formed of an insulating material.

[0020] The plasma processing apparatus 1 further includes a ring electrode 70. The ring electrode 70 is made of a conductive metal such as aluminum and is formed in a flat ring shape. The ring electrode 70 is provided outside the space between the lower electrode 18 and the upper electrode 30 and in the chamber 10. The ring electrode 70 is provided so as to surround the periphery of the substrate support part 14 in the raised state. The ring electrode 70 is provided along the side wall of the chamber 10 (or the chamber body 12). The inner diameter of the ring electrode 70 is formed slightly larger than the outer diameter of the substrate support part 14, and the ring electrode 70 is disposed with a gap from the side surface of the substrate support part 14 so as not to come into contact with the substrate support part 14 that is raised and lowered. The position of the ring electrode 70 is adjusted so that the upper surface of the substrate support part 14 set at the processing position and the upper surface of the ring electrode 70 are, for example, at the same height. Also, the position of the ring electrode 70 is adjusted so that the upper surface of the ring electrode 70 is higher than the upper surface of the substrate support part 14 set at the processing position. Also, for example, the position of the ring electrode 70 is adjusted so that the upper surface of the ring electrode 70 is lower than the upper surface of the substrate support part 14 at the processing position. The ring electrode 70 is connected to the side wall 12a of the chamber body 12 and electrically connected to the chamber body 12. The chamber body 12 is grounded via the wiring 13. The ring electrode 70 has an electrical path 52 connected to the ground by the chamber body 12 and the wiring 13. The electrical path 52 is composed of the chamber body 12 and the wiring 13 electrically connected to the ring electrode 70. The ring electrode 70 may be a mesh-shaped electrode providing a plurality of holes. The ring electrode 70 may be a slit-shaped electrode providing a plurality of long holes. In the embodiment, the ring electrode 70 corresponds to the ring member of the present disclosure, and the electrical path 52 corresponds to the second electrical path of the present disclosure.

[0021] The plasma processing apparatus 1 further includes an upper electrode 30. The upper electrode 30 is provided above the substrate support 14. The upper electrode 30 constitutes the ceiling of the chamber 10. The upper electrode 30 is electrically isolated from the chamber body 12. In one embodiment, the upper electrode 30 is fixed to the upper part of the chamber body 12 via an insulating member 32. In the embodiment, the upper electrode 30 corresponds to the electrode of the present disclosure.

[0022] In one embodiment, the upper electrode 30 is configured as a shower head. The upper electrode 30 may include a base member 33 and a top plate 34. The upper electrode 30 may further include an intermediate member 35. The base member 33, the top plate 34, and the intermediate member 35 are conductive and are formed of, for example, aluminum. The base member 33 is provided above the top plate 34. A heat insulating member 37 may be provided on the base member 33. The intermediate member 35 has a substantially ring shape and is sandwiched between the base member 33 and the top plate 34. The base member 33 and the top plate 34 provide a gas diffusion space 30d therebetween. The base member 33 provides a gas introduction port 33a that is connected to the gas diffusion space 30d. The top plate 34 provides a plurality of gas holes 34a. The plurality of gas holes 34a extend downward from the gas diffusion space 30d and penetrate the top plate 34 along the plate thickness direction.

[0023] The plasma processing apparatus 1 further includes a gas supply unit 36. The gas supply unit 36 ​​is configured to supply gas into the chamber 10. In one embodiment, the gas supply unit 36 ​​is connected to a gas introduction port 33a via a pipe 38. The gas supply unit 36 ​​may have one or more gas sources, one or more flow rate controllers, and one or more opening and closing valves. Each of the one or more gas sources is connected to the gas introduction port 33a via a corresponding flow rate controller and a corresponding opening and closing valve. The gas supply unit 36 ​​supplies various gases such as a process gas used in a degassing process, an annealing process, and a film forming process, which will be described later.

[0024] The plasma processing apparatus 1 further includes an exhaust device 40. The exhaust device 40 includes a pressure controller such as an automatic pressure control valve and a vacuum pump such as a turbo molecular pump or a dry pump. The exhaust device 40 is connected to an exhaust pipe 42. The exhaust pipe 42 is connected to the bottom wall 12b of the chamber 10 and communicates with the internal space of the chamber 10. The exhaust pipe 42 may be connected to a side wall of the chamber 10.

[0025] The plasma processing apparatus 1 further includes a high-frequency power supply 44. The high-frequency power supply 44 is connected to the upper electrode 30 via a matching unit 46. The high-frequency power supply 44 supplies power having a frequency below the VHF band (below 300 MHz) to the upper electrode 30. For example, the high-frequency power supply 44 supplies power having a frequency between 100 kHz and 13.56 MHz to the upper electrode 30. In the embodiment, the high-frequency power supply 44 corresponds to the power supply of the present disclosure.

[0026] The high frequency power supply 44 is connected to the upper electrode 30 via a matching box 46. The matching box 46 has a matching circuit that matches the impedance of the load of the high frequency power supply 44 to the output impedance of the high frequency power supply 44.

[0027] The plasma processing apparatus 1 further includes an impedance circuit 50. The lower electrode 18 of the substrate support 14 is grounded via the wiring 28a. The impedance circuit 50 is provided between the lower electrode 18 of the wiring 28a and the ground. The lower electrode 18 of the substrate support 14 is formed with an electrical path 51 connected to the ground by the wiring 28a via the impedance circuit 50. The electrical path 51 is composed of the wiring 28a electrically connected to the lower electrode 18 and the impedance circuit 50. In the embodiment, the electrical path 51 corresponds to the first electrical path of the present disclosure.

[0028] The impedance circuit 50 can provide a variable impedance between the lower electrode 18 and ground. The impedance circuit 50 can include a series or parallel circuit of an inductor and a capacitor. The inductor can be a variable inductor and the capacitor can be a variable capacitor.

[0029] The impedance of the impedance circuit 50 is set so that the impedance of the electrical path 51 is higher than the impedance of the electrical path 52. The impedance of the impedance circuit 50 can be set by a control unit 80, which will be described later. Note that the impedance of the impedance circuit 50 is set appropriately in advance, but may be dynamically changed by the control unit 80 during the process of forming a film on the substrate W.

[0030] The plasma processing apparatus 1 further includes a control unit 80. The control unit 80 is configured to control each unit of the plasma processing apparatus 1. The control unit 80 may be a computer including a processor, a storage unit such as a memory, an input device, a display device, a signal input / output interface, and the like. The storage unit of the control unit 80 stores a control program and recipe data. The processor of the control unit 80 executes the control program to control each unit of the plasma processing apparatus 1 according to the recipe data. The control unit 80 controls each unit of the plasma processing apparatus 1, thereby executing a film forming method according to the embodiment in the plasma processing apparatus 1.

[0031] Next, a flow of the plasma processing apparatus 1 according to the embodiment forming a film on the loaded substrate W under the control of the control unit 80 will be briefly described.

[0032] When the substrate W is carried into the plasma processing apparatus 1, the control unit 80 controls the lifting mechanism 26 to lower the substrate support unit 14 to a transfer position. The substrate W is placed on the substrate support unit 14 by a transfer mechanism such as a transfer arm (not shown). When a film is formed on the substrate W, the control unit 80 controls the lifting mechanism 26 to raise the substrate support unit 14. The control unit 80 controls the exhaust device 40 to reduce the pressure in the chamber 10 by the exhaust device 40. The control unit 80 controls the gas supply unit 36 ​​to supply various gases used in film formation from the gas supply unit 36 ​​and introduce the processing gas into the chamber 10 from the upper electrode 30. Then, the control unit 80 controls the high frequency power source 44 to supply power of a frequency equal to or lower than the VHF band from the high frequency power source 44 to the upper electrode 30 to generate plasma in the chamber 10, and a film is formed on the substrate W.

[0033] The impedance of the impedance circuit 50 is set so that the impedance of the electrical path 51 is higher than the impedance of the electrical path 52. For example, the impedance of the impedance circuit 50 is set so that the impedance of the electrical path 51 is 10 times or more higher than the impedance of the electrical path 52. For example, in the electrical path 52, the ring electrode 70 is a conductor and has low electrical resistance, but the sheath of the plasma generated around the ring electrode 70 has an impedance of about several hundred Ω. For this reason, the impedance of the impedance circuit 50 is set so that the impedance of the electrical path 51 is several kΩ or more.

[0034] Fig. 2 is a schematic diagram showing an example of the flow of power according to the embodiment. Fig. 2 shows a schematic configuration inside the chamber 10. Note that Fig. 2 shows a case where the substrate support 14 is made of a conductive metal, and the entire substrate support 14 is used as the lower electrode 18. A cover ring 15 is provided on the substrate support 14. The cover ring 15 covers the peripheral edge and side surfaces of the substrate support 14. The cover ring 15 is made of, for example, alumina.

[0035] The power supplied from the upper electrode 30 flows from the substrate support 14 (lower electrode 18) to ground via the electrical path 51, and also flows from the ring electrode 70 to ground via the electrical path 52. The impedance of the electrical path 51 is set to be higher than the impedance of the electrical path 52. For example, the impedance of the electrical path 51 is set to be 10 times higher than the impedance of the electrical path 52. This weakens the electrical coupling between the upper electrode 30 and the lower electrode 18, and most of the power supplied from the upper electrode 30 flows from the ring electrode 70 to ground via the electrical path 52. This reduces the current flowing through the lower electrode 18, and reduces the ion energy applied to the substrate W on the substrate support 14.

[0036] Next, a description will be given of a first experiment for measuring the ion energy distribution of the plasma processing apparatus 1. The first experiment described below does not limit the present disclosure.

[0037] (First experiment) In the first experiment, the ion energy distribution in plasma was measured in the plasma processing apparatus 1 without the ring electrode 70 and in the plasma processing apparatus 1 with the ring electrode 70. In the first experiment, the power of the electric power supplied from the high frequency power supply 44 was changed to 100, 200, 300, 500, and 800 W, and the ion energy distribution in plasma was measured. In the plasma processing apparatus 1 with the ring electrode 70, the impedance of the electrical path 51 was measured as 10 times higher than the impedance of the electrical path 52. Other conditions in the first experiment are shown below.

[0038] <Conditions for the first experiment> Gas supplied into chamber 10: a mixture of Ar gas and H2 gas Frequency of power supplied from high frequency power source 44: 450kHz Pressure in chamber 10: 500 mTorr (66.7 Pa) Temperature of substrate W: Less than 60℃ Distance between the top surface of the substrate support 14 and the bottom surface of the upper electrode 30: 13.5 mm

[0039] An example of the result of determining the ion energy distribution will be described. FIG. 3A and FIG. 3B are diagrams showing the ion energy distribution in the first experiment. FIG. 3A is the ion energy distribution measured by the plasma processing apparatus 1 without the ring electrode 70. FIG. 3B is the ion energy distribution measured by the plasma processing apparatus 1 with the ring electrode 70. As shown in FIG. 3A, in the plasma processing apparatus 1 without the ring electrode 70, ions with an ion energy of 40 eV or more are generated in the plasma. On the other hand, as shown in FIG. 3B, in the plasma processing apparatus 1 with the ring electrode 70, the ion energy of the ions contained in the plasma can be reduced to less than 10 eV. In the deposition of graphene, it is necessary to suppress the ion energy of the plasma low. Therefore, as in the embodiment, the plasma processing apparatus 1 with the ring electrode 70 can be used for the deposition of graphene.

[0040] Next, a description will be given of a film formation method for forming graphene on the substrate W by the plasma processing apparatus 1 according to the embodiment. Fig. 4 is a flowchart showing an example of the film formation method according to the embodiment.

[0041] A degassing process is performed to remove residual oxygen in the chamber 10 (step S10). The degassing process is performed before the substrate W is placed on the substrate support 14. In the degassing process, the distance between the upper surface of the substrate support 14 and the lower surface of the upper electrode 30 is preferably the same as that in the annealing process described below, or longer than that in the annealing process. In the degassing process, the distance between the upper surface of the substrate support 14 and the lower surface of the upper electrode 30 is more preferably 80 mm to 130 mm. In the degassing process, the pressure in the chamber 10 is preferably within a range of 100 m to 500 mTorr (13.3 to 66.66 Pa). In the degassing process, a process gas containing an inert gas is supplied into the chamber 10 to generate plasma, and the interior of the chamber 10 is exposed to the plasma to remove residual oxygen in the chamber 10. Examples of the inert gas contained in the process gas for the degassing process include N2 gas and Ar gas. The process gas for the degassing process includes at least one of N2 gas and Ar gas. For example, the control unit 80 controls the lifting mechanism 26 to raise the substrate support 14 to a position where the upper surface of the substrate support 14 is 80 mm to 130 mm from the lower surface of the substrate support 14. The control unit 80 controls the exhaust device 40 to reduce the pressure in the chamber 10 to 100 m to 500 mTorr (13.3 to 66.66 Pa) by the exhaust device 40. The control unit 80 controls the gas supply unit 36 ​​to supply a process gas containing an inert gas from the gas supply unit 36 ​​to introduce the process gas into the chamber 10 from the upper electrode 30. Then, the control unit 80 controls the high frequency power supply 44 to supply power of a frequency equal to or lower than the VHF band from the high frequency power supply 44 to the upper electrode 30 to generate plasma in the chamber 10 and remove residual oxygen in the chamber 10. The frequency of the power supplied from the high frequency power supply 44 may be the same as that of the film forming process described later. In the embodiment, step S10 corresponds to step d) of the present disclosure. Note that the degassing process may be omitted.

[0042] Next, the substrate W on which the film is to be formed is carried in (step S11). For example, the control unit 80 controls the lifting mechanism 26 to lower the substrate support 14 to the transfer position. The substrate W is placed on the substrate support 14 by a transfer mechanism such as a transfer arm (not shown). The substrate W preferably has a metal-containing film on the surface thereof on which graphene can be formed. The metal-containing film is a film made of any of Ru, Co, Cu, W, Mo, any oxide, any nitride, any oxynitride, or silicon, a silicon-containing oxide, a silicon-containing nitride, and a silicon-containing oxynitride. The metal-containing film may be formed on the substrate W in the plasma processing device 1 before the graphene is formed. In the embodiment, step S11 corresponds to step a) of the present disclosure.

[0043] Next, the substrate W is annealed (step S12). The annealing is performed as a pre-process of the film forming process described later in order to remove metal oxide from the metal-containing film on the surface of the substrate W. In the annealing, the distance between the upper surface of the substrate support 14 and the lower surface of the upper electrode 30 is preferably the same as or shorter than that in the degassing process described above. In the annealing, the distance between the upper surface of the substrate support 14 and the lower surface of the upper electrode 30 is more preferably 80 mm to 130 mm. In the annealing, the pressure in the chamber 10 is preferably within a range of 50 m to 2000 mTorr (6.7 to 266.4 Pa). In the annealing, the surface of the metal-containing film of the substrate W is exposed to a process gas containing a reducing gas to remove metal oxide from the metal-containing film. Examples of the reducing gas contained in the process gas for the annealing include hydrogen gas, CO gas, and hydrocarbon gas. The process gas for the annealing contains at least one of hydrogen gas, CO gas, and hydrocarbon gas. The process gas for the annealing process may further contain an inert gas. Examples of the inert gas contained in the process gas for the annealing process include Ar gas, He gas, N2 gas, and Kr gas. The process gas for the annealing process may contain at least one of Ar gas, He gas, N2 gas, and Kr gas. For example, the control unit 80 controls the lifting mechanism 26 to raise the substrate support unit 14 to a position where the upper surface of the substrate support unit 14 is at the same distance as in the degassing process, or the distance from the lower surface of the substrate support unit 14 is shorter than in the degassing process. The control unit 80 controls the exhaust device 40 to reduce the pressure in the chamber 10 to 50 m to 2000 mTorr (6.7 to 266.4 Pa) by the exhaust device 40. The control unit 80 controls the gas supply unit 36 ​​to supply a process gas containing a reducing gas from the gas supply unit 36 ​​to introduce the process gas from the upper electrode 30 into the chamber 10. In addition, the annealing treatment may include a first annealing treatment in which the surface of the metal-containing film of the substrate W is exposed to a reducing gas and an inert gas, and a second annealing treatment in which the surface of the metal-containing film of the substrate W is exposed to an inert gas after the first annealing treatment. In the embodiment, step S12 corresponds to step c) of the present disclosure. In addition, the annealing treatment may be omitted.

[0044] Next, a film formation process is performed to form a graphene film on the substrate W (step S13). In the film formation process, the distance between the upper surface of the substrate support 14 and the lower surface of the upper electrode 30 is preferably the same as that in the annealing process described above or shorter than that in the annealing process. In the film formation process, the distance between the upper surface of the substrate support 14 and the lower surface of the upper electrode 30 is preferably 10 mm to 80 mm, more preferably 20 mm to 30 mm. In the film formation process, a process gas containing a carbon-containing gas is supplied into the chamber 10 to generate plasma, and a graphene film is formed on the metal-containing film of the substrate W. Examples of the carbon-containing gas include hydrocarbon gases. Examples of the hydrocarbon gas include CxHy (x and y are integers of 1 or more) gases such as C2H2 gas, CH4 gas, and C2H4 gas. The process gas for the film formation process includes at least one of CxHy (x and y are integers of 1 or more) gases such as C2H2 gas, CH4 gas, and C2H4 gas. The processing gas may contain an inert gas. Examples of the inert gas include Ar gas, He gas, N2 gas, and Kr gas. The processing gas for the film formation process may contain at least one of Ar gas, He gas, N2 gas, and Kr gas. The temperature of the substrate W in the film formation process is preferably within a range of 300°C to 500°C. The pressure in the chamber 10 in the film formation process is preferably within a range of 200m to 600mTorr (26.7 to 80 Pa). The power of the electric power in the film formation process is preferably within a range of 50W to 1000W. The frequency of the electric power in the film formation process may be a frequency below the VHF band, and is preferably within a range of 100kHz to 13.56MHz. For example, the control unit 80 controls the lifting mechanism 26 to raise the substrate support 14 to a predetermined processing position where the upper surface of the substrate support 14 is 10mm to 80mm from the lower surface of the substrate support 14. The position of the ring electrode 70 is adjusted so that the upper surface of the substrate support part 14 raised to the processing position and the upper surface of the ring electrode 70 are at the same height. The ring electrode 70 surrounds the periphery of the substrate support part 14 at the processing position. The control part 80 controls the heater power supply 22 to heat the substrate W with the heater 20 so that the temperature of the substrate W is within a range of 300°C to 500°C. The control part 80 may adjust the temperature of the substrate W to the film formation temperature from the time of the annealing process.The control unit 80 controls the exhaust device 40 to reduce the pressure inside the chamber 10 to 200 m to 600 mTorr (26.7 to 80 Pa) by the exhaust device 40. The control unit 80 controls the gas supply unit 36 ​​to supply a process gas containing a carbon-containing gas from the gas supply unit 36 ​​and introduce the process gas into the chamber 10 from the upper electrode 30. Then, the control unit 80 controls the high frequency power supply 44 to supply power with a frequency equal to or lower than the VHF band from the high frequency power supply 44 to the upper electrode 30 to generate plasma in the chamber 10 and form a graphene film on the metal-containing film of the substrate W. In the embodiment, step S13 corresponds to step b) of the present disclosure.

[0045] Next, the substrate W on which the graphene film has been formed is carried out (step S14). For example, the control unit 80 controls the lifting mechanism 26 to lower the substrate support unit 14 to the transfer position. The substrate W is taken out of the substrate support unit 14 by a transfer mechanism such as a transfer arm (not shown) and carried out.

[0046] Next, a second experiment and a third experiment will be described in which graphene was formed on a substrate W by the plasma processing apparatus 1 according to the embodiment. The second experiment and the third experiment described below do not limit the present disclosure.

[0047] (Second experiment) In the second experiment, graphene was formed on a substrate W by the film formation method shown in Fig. 4. In the second experiment, graphene was formed on a substrate W having a Co film formed on its surface as a metal-containing film. The common processing conditions for the degassing process (step S10), the annealing process (step S12), and the film formation process (step S13) are shown below. <Common treatment conditions for the second experiment> Frequency of power supplied from high frequency power source 44: 450kHz Temperature of substrate W: 400℃

[0048] The individual conditions for the degassing process, the annealing process, and the film-forming process are shown below. The gas flow rates for the degassing process, the annealing process, and the film-forming process were set to appropriate values. <Degassing treatment conditions in the second experiment> Gas supplied into chamber 10: N2 gas Power of the power supplied from the high frequency power source 44: 300W Pressure in chamber 10: 300 mTorr (40.0 Pa) Distance between the top surface of the substrate support 14 and the bottom surface of the upper electrode 30: 80 mm Processing time: 10 min <Annealing Treatment Conditions in the Second Experiment> Gas supplied into chamber 10: H2 gas Power supplied from high frequency power source 44: 0W (plasma-less) Pressure in chamber 10: 50 mTorr (6.7 Pa) Distance between the top surface of the substrate support 14 and the bottom surface of the upper electrode 30: 80 mm Processing time: 10 min <Processing conditions for film formation in the second experiment> Gas supplied into chamber 10: a mixture of C2H2 gas, H2 gas, and Ar gas Power of the power supplied from the high frequency power source 44: 300W Pressure in chamber 10: 500 mTorr (66.7 Pa) Distance between the top surface of the substrate support 14 and the bottom surface of the upper electrode 30: 20 mm Processing time: 1 min

[0049] In the second experiment, CoOx is removed from the Co film on the surface of the substrate W by annealing, and graphene is formed on the Co film of the substrate W by film formation. In the second experiment, the Raman spectrum of the substrate W on which the graphene film was formed was measured. FIG. 5 shows the Raman spectrum of the substrate W on which the graphene film was formed in the second experiment. The horizontal axis of FIG. 5 shows the wavelength shift amount (Raman shift (cm) from the excitation wavelength. -1 )). The vertical axis shows the signal intensity of each wavelength normalized to a predetermined signal intensity of 1. In the Raman spectrum shown in FIG. 5, a G peak and a D peak can be confirmed. This confirms that a graphene film has been formed on the substrate W.

[0050] (Third experiment) In the third experiment, graphene was formed on a substrate W by the film formation method shown in FIG. 4. In the third experiment, graphene was formed on a substrate W having a Ru film formed on its surface as a metal-containing film. In the third experiment, a second annealing process was performed after the first annealing process in the annealing process (step S12). The common process conditions for the degassing process (step S10), the first annealing process (step S12), the second annealing process (step S12), and the film formation process (step S13) are shown below. <Common treatment conditions for the third experiment> Frequency of power supplied from high frequency power source 44: 450kHz Temperature of substrate W: 400℃

[0051] The individual conditions for the degassing process, the annealing process, and the film-forming process are shown below. The gas flow rates for the degassing process, the annealing process, and the film-forming process were set to appropriate values. <Degassing treatment conditions in the third experiment> Gas supplied into chamber 10: N2 gas Power of the power supplied from the high frequency power source 44: 300W Pressure in chamber 10: 300 mTorr (40.0 Pa) Distance between the top surface of the substrate support 14 and the bottom surface of the upper electrode 30: 130 mm Processing time: 10 min <Processing conditions of the first annealing treatment in the third experiment> Gas supplied into chamber 10: a mixture of H2 gas and Ar gas Power supplied from high frequency power source 44: 0W (plasma-less) Pressure in chamber 10: 400 mTorr (53.2 Pa) Distance between the top surface of the substrate support 14 and the bottom surface of the upper electrode 30: 90 mm Processing time: 1 min <Conditions of the second annealing treatment in the third experiment> Gas supplied into chamber 10: Ar gas Power supplied from high frequency power source 44: 0W (plasma-less) Pressure in chamber 10: 2000 mTorr (266.6 Pa) Distance between the top surface of the substrate support 14 and the bottom surface of the upper electrode 30: 90 mm Processing time: 10 min <Processing conditions for film formation in the third experiment> Gas supplied into chamber 10: a mixture of C2H2 gas, H2 gas, and Ar gas Power of the power supplied from the high frequency power source 44: 300W Pressure in chamber 10: 300 mTorr (40.0 Pa) Distance between the top surface of the substrate support 14 and the bottom surface of the upper electrode 30: 60 mm Processing time: 1 min

[0052] In the third experiment, RuOx is removed from the Ru film on the surface of the substrate W by the first annealing process and the second annealing process, and graphene is formed on the Ru film of the substrate W by the film formation process. As a result of measuring the Raman spectrum of the substrate W on which the graphene film was formed in the third experiment, a G peak and a D peak can be confirmed in the Raman spectrum. This confirms that a graphene film is formed on the substrate W.

[0053] In addition, graphene was formed on the substrate W by changing the frequency of the power supplied from the high frequency power supply 44, and as a result, a graphene film was formed on the substrate W with a frequency between 100 kHz and 13.56 MHz. In addition, graphene was formed on the substrate W by changing the distance between the upper surface of the substrate support part 14 and the lower surface of the upper electrode 30, and as a result, a graphene film was formed on the substrate W with a distance between the upper surface of the substrate support part 14 and the lower surface of the upper electrode 30 between 10 mm and 80 mm. However, when the distance between the upper surface of the substrate support part 14 and the lower surface of the upper electrode 30 is shortened, carbon nanowalls (CNWs) are formed in the graphene film. When a graphene film with good continuity is formed, it is more preferable that the distance between the upper surface of the substrate support part 14 and the lower surface of the upper electrode 30 is 30 mm to 60 mm.

[0054] Here, in conventional graphene deposition using microwaves, graphene cannot be deposited unless the pressure inside the chamber is reduced to a low pressure of about 20 mTorr to 80 mTorr (2.7 to 10.7 Pa).

[0055] In contrast, the plasma processing apparatus 1 according to the embodiment can form graphene even at a high pressure of 500 mTorr (66.7 Pa), for example, as shown in the processing conditions of the film formation process in the second experiment described above. This eliminates the need for the plasma processing apparatus 1 to use a turbo molecular pump in the exhaust device 40. Furthermore, in the case of considering improving the productivity of graphene film formation, the configuration of the present disclosure can be used in a multi-wafer type film formation apparatus. Furthermore, since graphene can be formed with a short gap, the chamber volume can be reduced, and the amount of film formation gas used can be reduced.

[0056] In the above embodiment, the electrical path 52 from the ring electrode 70 to the ground is a conductive path from the ring electrode 70 to the ground via the chamber body 12 and the wiring 13. However, the disclosed technology is not limited to this. For example, the electrical path 52 may be any conductive path as long as it is a conductive path through which a current flows from the ring electrode 70 to the ground. For example, the ring electrode 70 may be insulated from the chamber body 12, and a grounded wiring may be connected to the ring electrode 70 to serve as the electrical path 52. The electrical path 51 may also be any conductive path as long as it is a conductive path from the lower electrode 18 of the substrate support 14 to the ground.

[0057] The embodiment has been described above. As described above, the film forming method according to the embodiment includes step a) (step S11) and step b) (step S13). In step a), the substrate W is placed on the substrate support 14 inside the chamber 10, in which the substrate support 14 connected to the ground via the electrical path 51 is disposed inside, the conductive ring electrode 70 connected to the ground via the electrical path 52 is disposed around the substrate support 14, and the upper electrode 30 is disposed facing the substrate support 14. In step b), while supplying a process gas containing a carbon-containing gas into the chamber 10, the impedance of the electrical path 51 is made higher than the impedance of the electrical path 52, and power of a frequency equal to or lower than the VHF band is supplied to the upper electrode 30 to generate plasma in the chamber 10, and graphene is formed on the substrate W. As a result, the film forming method according to the embodiment can form graphene on the substrate W even with plasma generated by power of a frequency equal to or lower than the VHF band.

[0058] Furthermore, in step b), the impedance of the electrical path 51 is at least 10 times higher than the impedance of the electrical path 52. As a result, most of the power supplied from the upper electrode 30 flows from the ring electrode 70 to the ground via the electrical path 52. This makes it possible to significantly reduce the ion energy of the ions contained in the plasma. As a result, the film formation method according to the embodiment can form graphene on the substrate W even with plasma generated by power with a frequency equal to or lower than the VHF band.

[0059] In step b), the distance between the upper surface of the substrate support 14 and the lower surface of the upper electrode 30 is 10 mm to 80 mm. In step b), power having a frequency between 100 kHz and 13.56 MHz is supplied to the upper electrode 30. The carbon-containing gas is a hydrocarbon gas. The process gas includes an inert gas. The inert gas is at least one of Ar gas, He gas, N2 gas, and Kr gas. The substrate support 14 is provided with a heater. In step b), the heater adjusts the temperature of the substrate W to within a range of 300°C to 500°C. In step b), the pressure in the chamber 10 is 200 m to 600 mTorr. In step b), the power of the power supplied to the upper electrode 30 is within a range of 50 W to 1000 W. In addition, the substrate W has a metal-containing film formed on its surface, on which graphene can be formed. The metal-containing film is any of a film of Ru, Co, Cu, W, and Mo, any of an oxide film, and any of a nitride film. As a result, the film formation method according to the embodiment can form a graphene film on the substrate W even with plasma generated by power with a frequency of VHF band or lower.

[0060] The film forming method according to the embodiment further includes a step c) (step S12). In the step c), the surface of the metal-containing film is exposed to a second process gas containing a reducing gas before the step b). In the step c), the distance between the upper surface of the substrate support 14 and the lower surface of the upper electrode 30 is 80 mm to 130 mm. In the step c), the pressure in the chamber 10 is 50 mTorr to 2000 mTorr. The reducing gas is at least one of hydrogen gas, CO gas, and hydrocarbon gas. In this way, the film forming method according to the embodiment can remove metal oxide from the metal-containing film on the surface of the substrate W.

[0061] In addition, the distance between the upper surface of the substrate support 14 and the lower surface of the upper electrode 30 is configured to be changeable. In step c), the distance between the upper surface of the substrate support 14 and the lower surface of the upper electrode 30 is set to be the same as in step b) or longer than in step b). In this way, the film formation method according to the embodiment can remove metal oxide from the metal-containing film on the surface of the substrate W.

[0062] Moreover, the film formation method according to the embodiment further includes a step d) (step S10). In the step d), before the steps a) and b), a third process gas containing an inert gas is supplied into the chamber 10 while power is supplied to the upper electrode 30 to remove residual oxygen in the chamber 10. In the step d), the distance between the upper surface of the substrate support 14 and the lower surface of the upper electrode 30 is 80 mm to 130 mm. Thus, the film formation method according to the embodiment can remove residual oxygen in the chamber 10 from the graphene film formation.

[0063] It should be noted that the embodiments disclosed herein are illustrative in all respects and should not be construed as limiting. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims.

[0064] Furthermore, the following supplementary notes are disclosed regarding the above embodiment.

[0065] (Appendix 1) a) placing a substrate on a stage inside a processing vessel, the stage being connected to ground via a first electrical path, a conductive ring member being arranged around the stage and connected to ground via a second electrical path, and an electrode being arranged opposite the stage; b) supplying a processing gas containing a carbon-containing gas into the processing vessel, while setting the impedance of the first electrical path to be higher than the impedance of the second electrical path, supplying power having a frequency equal to or lower than a VHF (Very High Frequency) band to the electrode to generate plasma in the processing vessel, and depositing graphene on the substrate; A film forming method comprising the steps of:

[0066] (Appendix 2) In the step b), the impedance of the first electrical path is 10 times or more higher than the impedance of the second electrical path. 2. The method for forming a film according to claim 1.

[0067] (Appendix 3) In the step b), the distance between the upper surface of the stage and the lower surface of the electrode is 10 mm to 80 mm. 3. The film forming method according to claim 1 or 2.

[0068] (Appendix 4) In step b), power having a frequency between 100 kHz and 13.56 MHz is supplied to the electrode. 4. The film forming method according to any one of claims 1 to 3.

[0069] (Appendix 5) The carbon-containing gas is a hydrocarbon gas. 5. The film forming method according to any one of claims 1 to 4.

[0070] (Appendix 6) The process gas includes an inert gas. 6. The film forming method according to any one of claims 1 to 5.

[0071] (Appendix 7) The inert gas is at least one of Ar gas, He gas, N2 gas, and Kr gas. 7. The film forming method according to claim 6.

[0072] (Appendix 8) The stage is provided with a heater, In the step b), the temperature of the substrate is adjusted to within a range of 300° C. to 500° C. by the heater. The film forming method according to any one of claims 1 to 7.

[0073] (Appendix 9) In the step b), the pressure in the processing vessel is 200 to 600 mTorr. The film forming method according to any one of claims 1 to 8.

[0074] (Appendix 10) In the step b), the power of the electric power supplied to the electrode is within a range of 50 W to 1000 W. The film forming method according to any one of claims 1 to 9.

[0075] (Appendix 11) The substrate has a surface on which a metal-containing film capable of forming a graphene film is formed. The film forming method according to any one of claims 1 to 10.

[0076] (Appendix 12) The metal-containing film is any one of a film of Ru, Co, Cu, W, and Mo, a film of any oxide thereof, and a film of any nitride thereof. 12. The film forming method according to claim 11.

[0077] (Appendix 13) c) prior to step b), further comprising exposing the surface of the metal-containing film to a second process gas comprising a reducing gas. 13. The film forming method according to claim 11 or 12.

[0078] (Appendix 14) In the step c), the distance between the upper surface of the stage and the lower surface of the electrode is 80 mm to 130 mm. 14. The film forming method according to claim 13.

[0079] (Appendix 15) In the step c), the pressure in the processing vessel is 50 mTorr to 2000 mTorr. 15. The film forming method according to claim 13 or 14.

[0080] (Appendix 16) The reducing gas is at least one of hydrogen gas, CO gas, and a hydrocarbon gas. 16. The film forming method according to any one of claims 11 to 15.

[0081] (Appendix 17) The distance between the upper surface of the stage and the lower surface of the electrode is changeable, In the step c), the distance between the upper surface of the stage and the lower surface of the electrode is set to be the same as or longer than that in the step b). 17. The film forming method according to any one of claims 11 to 16.

[0082] (Appendix 18) d) before the step a) and the step b), a step of supplying power to the electrode while supplying a third process gas containing an inert gas into the processing vessel to remove residual oxygen in the processing vessel; The film forming method according to any one of claims 1 to 17.

[0083] (Appendix 19) In the step d), the distance between the upper surface of the stage and the lower surface of the electrode is 80 mm to 130 mm. 19. The method for forming a film according to claim 18.

[0084] (Appendix 20) A processing vessel; a stage configured to be disposed inside the processing chamber, to have a substrate placed thereon, and to be connected to ground via a first electrical path; a ring member having electrical conductivity, disposed around the stage, and configured to be connected to ground via a second electrical path; an electrode configured to be disposed inside the processing vessel and facing the stage; a gas supply unit configured to supply a processing gas into the processing chamber; A power source configured to be able to supply power having a frequency of VHF (Very High Frequency) or lower to the electrodes; a control unit configured to control the power source to supply electric power having a frequency of VHF or lower to the electrode while keeping the impedance of the first electrical path higher than the impedance of the second electrical path, while supplying a processing gas containing a carbon-containing gas from the gas supply unit into the processing vessel; A plasma processing apparatus comprising: [Explanation of symbols]

[0085] 1. Plasma processing equipment 10. Chamber 12 Chamber body 12a side wall 12b Bottom wall 12c aperture 13 Wiring 14 Substrate support 15 Covering 16 Support member 18 Lower electrode 20 Heater 22 Heater power supply 25 Flange 26 Lifting mechanism 27 Bellows 28a Wiring 28b Wiring 30 Upper electrode 30d Gas diffusion space 32 Insulating materials 33 Base material 33a Gas inlet port 34 Tabletop 34a Gas hole 36 Gas Supply Section 38 Piping 40 Exhaust system 44 High frequency power supply 46 Matching box 50 Impedance Circuit 51 Electrical Path 52 Electrical Path 70 Ring Electrode 80 Control section

Claims

1. a) placing a substrate on a stage inside a processing vessel, the stage being connected to ground via a first electrical path, a conductive ring member being arranged around the stage and connected to ground via a second electrical path, and an electrode being arranged opposite the stage; b) supplying a processing gas including a carbon-containing gas into the processing vessel, setting the impedance of the first electrical path to be higher than the impedance of the second electrical path, supplying power having a frequency equal to or lower than a very high frequency (VHF) band to the electrode to generate plasma in the processing vessel, and depositing graphene on the substrate; A film forming method comprising the steps of:

2. In the step b), the impedance of the first electrical path is 10 times or more higher than the impedance of the second electrical path. The film forming method according to claim 1 .

3. In the step b), the distance between the upper surface of the stage and the lower surface of the electrode is 10 mm to 80 mm. The film forming method according to claim 1 or 2.

4. In step b), the electrodes are supplied with power having a frequency between 100 kHz and 13.56 MHz. The film forming method according to claim 1 .

5. The carbon-containing gas is a hydrocarbon gas. The film forming method according to claim 1 .

6. The process gas includes an inert gas. The film forming method according to claim 1 .

7. The inert gas is Ar gas, He gas, N 2 gas, Kr gas, or both. The film forming method according to claim 6.

8. The stage is provided with a heater, In the step b), the temperature of the substrate is adjusted to within a range of 300° C. to 500° C. by the heater. The film forming method according to claim 1 .

9. In the step b), the pressure in the processing vessel is 200 to 600 mTorr. The film forming method according to claim 1 .

10. In the step b), the power of the electric power supplied to the electrode is in the range of 50 W to 1000 W. The film forming method according to claim 1 .

11. The substrate has a surface on which a metal-containing film capable of forming a graphene film is formed. The film forming method according to claim 1 .

12. The metal-containing film is any one of a film of Ru, Co, Cu, W, and Mo, a film of any oxide thereof, and a film of any nitride thereof. The film forming method according to claim 11.

13. c) prior to step b), further comprising exposing the surface of the metal-containing film to a second process gas comprising a reducing gas. The film forming method according to claim 11 or 12.

14. In the step c), the distance between the upper surface of the stage and the lower surface of the electrode is 80 mm to 130 mm. The film forming method according to claim 13.

15. In the step c), the pressure in the processing vessel is 50 mTorr to 2000 mTorr. The film forming method according to claim 13.

16. The reducing gas is at least one of hydrogen gas, CO gas, and a hydrocarbon gas. The film forming method according to claim 13.

17. The distance between the upper surface of the stage and the lower surface of the electrode is changeable, In the step c), the distance between the upper surface of the stage and the lower surface of the electrode is set to be the same as or longer than that in the step b). The film forming method according to claim 13.

18. d) before the step a) and the step b), supplying a third process gas containing an inert gas into the processing vessel while supplying power to the electrode to remove residual oxygen in the processing vessel; The film forming method according to claim 1 .

19. In the step d), the distance between the upper surface of the stage and the lower surface of the electrode is 80 mm to 130 mm. The film forming method according to claim 18.

20. A processing vessel; a stage configured to be disposed inside the processing chamber, to have a substrate placed thereon, and to be connected to ground via a first electrical path; a ring member having electrical conductivity, disposed around the stage, and configured to be connected to ground via a second electrical path; an electrode configured to be disposed inside the processing vessel and facing the stage; a gas supply unit configured to supply a processing gas into the processing chamber; A power source configured to be able to supply power having a frequency equal to or lower than a VHF (Very High Frequency) band to the electrodes; a control unit configured to control the power source to supply electric power having a frequency of VHF or lower to the electrode while keeping the impedance of the first electrical path higher than the impedance of the second electrical path, while supplying a processing gas containing a carbon-containing gas from the gas supply unit into the processing vessel; A plasma processing apparatus comprising:

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