Substrate processing method and substrate processing device

Abstract

Provided are a substrate processing method and a substrate processing device for forming a target film on a base film while suppressing damage to the base film.　The substrate processing method includes: a step for placing a substrate having a base film on a substrate support part of a placement table; a step for placing a dummy substrate on a dummy substrate support part in a manner shielding the substrate at a position higher than the position of the substrate; and a step for supplying a processing gas into a processing container and generating plasma of the processing gas, and exposing the substrate and the dummy substrate to the plasma to thereby form a target film on the base film. The dummy substrate is disposed on the substrate side, relative to the intermediate position between the lower surface of the top wall of the processing container and the upper surface of the substrate.

Description

Substrate Processing Method and Substrate Processing Apparatus

[0001] The present disclosure relates to a substrate processing method and a substrate processing apparatus.

[0002] Patent Document 1 discloses a plasma CVD apparatus having a plasma chamber provided with an electron cyclotron resonance type plasma generation means and a workpiece holder, and a shielding member provided between a plasma high density region formed by the plasma generation means and the workpiece holder.

[0003] Patent Document 2 discloses a plasma CVD apparatus including a vacuum chamber forming a processing chamber, a substrate stage installed in the processing chamber, gas introduction means for introducing a raw material gas into the processing chamber, plasma generation means for generating plasma that decomposes the raw material gas, and a plurality of mesh-like shielding plates installed between the plasma generation space and the substrate stage.

[0004] Japanese Patent Application Laid-Open No. 6-188206, Japanese Patent Application Laid-Open No. 2008-38164

[0005] On one aspect, the present disclosure provides a substrate processing method and a substrate processing apparatus for forming a target film on a base film while suppressing damage to the base film.

[0006] In order to solve the above problems, according to one aspect, a step of placing a substrate having a base film on a substrate support portion of a mounting table, a step of placing a dummy substrate on a dummy substrate support portion so as to shield the substrate at a position higher than the position of the substrate, a step of supplying a processing gas into a processing container to generate plasma of the processing gas, exposing the substrate and the dummy substrate to the plasma, and forming a target film on the base film, and the dummy substrate is disposed on the side of the substrate rather than at an intermediate position between the lower surface of the top wall of the processing container and the upper surface of the substrate. A substrate processing method can be provided.

[0007] According to one aspect, a substrate processing method and a substrate processing apparatus for forming a target film on a base film while suppressing damage to the base film can be provided.

[0008] An example of a diagram showing the configuration of a plasma processing apparatus equipped with a microwave plasma source according to one embodiment. An example of a horizontal cross-sectional view of the plasma processing apparatus with the mounting table viewed from above. An example of a flowchart showing a substrate processing method. An example of a schematic cross-sectional diagram showing the structure of the substrate W after substrate processing. An example of a graph for evaluating damage to the undercoat. An example of a graph for evaluating damage to the undercoat. An example of a schematic diagram explaining ion acceleration. An example of a schematic diagram explaining ion acceleration at low pressure. An example of a schematic diagram explaining ion acceleration at high pressure when a dummy substrate is grounded. An example of a schematic diagram explaining ion acceleration at high pressure when a dummy substrate is grounded.

[0009] Various exemplary embodiments will be described in detail below with reference to the drawings. In each drawing, the same or corresponding parts will be denoted by the same reference numerals.

[0010] [Plasma Processing Apparatus 1] An example of the configuration of a plasma processing apparatus (substrate processing apparatus) 1 that performs the film deposition method according to this embodiment will be described with reference to Figures 1 and 2. Figure 1 is an example of a diagram showing an example of the configuration of a plasma processing apparatus 1 equipped with a microwave plasma source according to one embodiment. Figure 2 is an example of a horizontal cross-sectional view of the plasma processing apparatus 1 viewed from above, with the mounting table 11. The plasma processing apparatus 1 is a microwave plasma CVD (chemical vapor deposition) apparatus that deposits a target film 420 (see Figure 4, described later) on a substrate W having a base film 410 (see Figure 4, described later).

[0011] Here, the underlayer film 410 is, for example, a Low-k film (low dielectric constant film, interlayer insulating film). As the Low-k film, for example, any of the following can be used: a SiOC film, a SiOF film, etc. The target film 420 is a film composed of a two-dimensional material such as a graphene film or a hexagonal boron nitride (h-BN) film. In the following description, the plasma processing apparatus 1 will be described using the case where a graphene film is deposited on the substrate W as an example.

[0012] The plasma processing apparatus 1 comprises a processing vessel 10 and a plasma source 2. The processing vessel 10 is a substantially cylindrical vessel made of a metal material such as aluminum, which is airtight, and is grounded. The plasma source 2 introduces microwaves into the processing vessel 10 to form a surface wave plasma. The top wall 10a of the processing vessel 10 is constructed by fitting dielectric members (hereinafter referred to as dielectric windows 56) of a plurality of microwave radiation mechanisms 42 into a metal main body. As a result, the plasma source 2 introduces microwaves into the processing vessel 10 through the plurality of dielectric windows 56 of the top wall 10a.

[0013] The plasma processing apparatus 1 has a control unit (control section) 130. The control unit 130 is, for example, a computer and has a program storage unit (not shown). The program storage unit stores a program that controls the processing of a substrate W, such as a semiconductor wafer, in the plasma processing apparatus 1. The program may be recorded on a computer-readable storage medium such as a computer-readable hard disk (HD), flexible disk (FD), compact disk (CD), magnetic optical disk (MO), or memory card, and installed from that storage medium to the control unit 130.

[0014] Inside the processing container 10, a mounting table 11 for horizontally supporting the substrate W is provided, supported by a cylindrical support member 12 erected at the center of the bottom of the processing container 10 via an insulating member 12a. The materials constituting the mounting table 11 and the support member 12 are, for example, metals such as aluminum with anodized (anodic oxidation) surfaces, or insulating materials (ceramics, etc.) having high-frequency electrodes inside. The mounting table 11 also has a substrate support portion (substrate mounting portion) 11a for supporting (placing) the substrate W. The substrate support portion 11a may be a recess provided on the upper surface of the mounting table 11.

[0015] Although not shown in the diagram, the mounting table 11 is also provided with a temperature control mechanism, a gas channel for supplying heat transfer gas to the back surface of the substrate W, and lifting pins for moving the substrate W up and down. Furthermore, an electrostatic chuck for electrostatically adsorbing the substrate W may also be provided.

[0016] Furthermore, the mounting base 11 is electrically grounded.

[0017] An exhaust pipe 15 is connected to the bottom side of the processing container 10, and an exhaust device 16 including a vacuum pump is connected to this exhaust pipe 15. By operating this exhaust device 16, the inside of the processing container 10 can be evacuated, and the pressure inside the processing container 10 can be reduced and set to a predetermined pressure. The exhaust device 16 includes a vacuum pump, an APC (Adaptive Pressure Controller) valve, a pressure sensor, etc. (not shown). The pressure sensor may be installed inside the processing container 10. In addition, an inlet / outlet 17 for loading and unloading substrates W and a gate valve 18 for opening and closing this inlet / outlet 17 are provided on the side wall 10b of the processing container 10.

[0018] Furthermore, the plasma processing apparatus 1 has a gas shower section (gas supply hole) 23 that supplies a predetermined gas into the processing container 10 from the top wall 10a of the processing container 10. The gas shower section 23 supplies a predetermined gas into the processing container 10 from the top wall 10a of the processing container 10.

[0019] The gas shower section 23 is installed on the top wall of the processing container 10 and supplies gas transported from the gas supply section 83 through the gas line 86 into the processing container 10.

[0020] A processing gas (film-forming gas) is supplied from the gas shower section 23. For example, when forming a graphene film, a carbon-hydrogen gas (e.g., acetylene) is supplied from the gas shower section 23. When forming a hexagonal boron nitride (h-BN) film, a boron-containing gas (e.g., diborane) is supplied from the gas shower section 23. Other processing gases besides film-forming gases may also be supplied from the gas shower section 23. For example, when forming a hexagonal boron nitride (h-BN) film, a nitrogen-containing gas (e.g., ammonia) is supplied from the gas shower section 23. A diluent gas may also be supplied from the gas shower section 23. Argon (Ar) gas and helium (He) gas, used as diluent gases, may also be used as gases for plasma excitation.

[0021] Furthermore, the gas supply unit 83 is configured to allow individual control of the supply and cessation of each gas when supplying multiple gases.

[0022] The plasma source 2 includes a microwave output unit 30 that distributes microwaves to multiple paths and outputs microwaves, and a microwave transmission unit 40 that transmits the microwaves output from the microwave output unit 30.

[0023] The microwave output unit 30 includes a microwave power supply, a microwave oscillator, an amplifier, and a distributor. The microwave power supply supplies power to the microwave oscillator. The microwave oscillator generates microwaves at a predetermined frequency (e.g., 860 MHz) using, for example, a PLL oscillation. The amplifier amplifies the generated microwaves. The distributor distributes the microwaves amplified by the amplifier while matching the impedance of the input and output sides to minimize microwave loss. In addition to 860 MHz, various frequencies in the range of 700 MHz to 3 GHz, such as 915 MHz, can be used as the microwave frequency.

[0024] The microwave transmission unit 40 has a plurality of amplifier units 41 and a plurality of microwave radiation mechanisms 42 provided corresponding to the amplifier units 41. For example, one microwave radiation mechanism 42 is located in the center of the top wall 10a, and six more are arranged at equal intervals around the circumference centered on the central one, for a total of seven. In this example, the microwave radiation mechanisms 42 are arranged such that the distance between the central microwave radiation mechanism 42 and the outer microwave radiation mechanisms 42 is equal to the distance between the outer microwave radiation mechanisms 42.

[0025] The amplifier section 41 guides the microwaves distributed by the distributor to each microwave radiation mechanism 42. Each microwave radiation mechanism 42 has a coaxial tube 51. The coaxial tube 51 has a coaxial microwave transmission path consisting of a cylindrical outer conductor 51a and a rod-shaped inner conductor 51b located in its center. Each microwave radiation mechanism 42 has a feeding antenna (not shown) that supplies the microwaves amplified by the amplifier section 41 to the coaxial tube 51. Furthermore, each microwave radiation mechanism 42 has a tuner that matches the impedance of the load to the characteristic impedance of the microwave power supply, and an antenna section that radiates microwaves from the coaxial tube into the processing container 10.

[0026] The antenna section is located at the lower end of the coaxial tube 51 and is fitted into the metal portion of the top wall 10a of the processing container 10. The antenna section has a dielectric window 56, and microwaves transmitted through the dielectric window 56 generate surface wave plasma in the portion directly below the dielectric window 56 inside the processing container 10.

[0027] Multiple plasma sources 2 (dielectric windows 56) are provided: one in the center of the ceiling and six on the outer periphery. Each of the multiple plasma sources 2 (dielectric windows 56) can independently control the microwave power supplied from each plasma source 2. The microwave power supplied from the plasma sources 2 (dielectric windows 56) on the outer periphery may be higher than or equal to the microwave power supplied from the plasma source 2 in the center.

[0028] The film deposition method of this embodiment can be carried out using a plasma processing apparatus 1 that supplies microwave power from a plasma source 2 located on the top wall 10a of the processing container 10.

[0029] Furthermore, the mounting base 11 has a dummy substrate support mechanism 110 that supports the dummy substrate (shielding plate) 120. For example, three dummy substrate support mechanisms 110 are provided in the circumferential direction of the mounting base 11. The dummy substrate support mechanism 110 has a shaft portion 111 and a dummy substrate support portion 112.

[0030] As shown in Figure 2, the shaft portion 111 is positioned radially outward from the substrate support portion 11a of the mounting base 11. The shaft portion 111 is supported on the mounting base 11 so as to be movable in the axial direction (up and down direction). In addition, the shaft portion 111 is supported on the mounting base 11 so as to be rotatable.

[0031] The dummy substrate support portion 112 is supported by the shaft portion 111 and is formed to protrude horizontally from the shaft portion 111.

[0032] Furthermore, the dummy substrate support mechanism 110 includes a lifting mechanism (not shown) for raising and lowering the shaft portion 111, and a rotation mechanism (not shown) for rotating the shaft portion 111.

[0033] The lifting mechanism raises and lowers the shaft portion 111 to adjust the shielding plate height H1 (spacing) from the upper surface (front) of the substrate W placed on the substrate support portion 11a of the mounting base 11 to the lower surface (back) of the dummy substrate 120 placed on the dummy substrate support portion 112.

[0034] By rotating the shaft portion 111 using a rotation mechanism, it is possible to switch between a first state in which the dummy substrate support portion 112 is retracted from above the substrate support portion 11a (see solid line in Figure 2) and a second state in which the dummy substrate support portion 112 is positioned above the substrate support portion 11a (see dashed line in Figure 2).

[0035] In the first state, when viewed from above (see Figure 2), the dummy substrate support 112 is positioned radially outward from the substrate support 11a. This allows the substrate W to be loaded into, placed on, and removed from the substrate support 11a without interfering with the dummy substrate support 112.

[0036] In the second state, the dummy substrate support 112 is positioned so as to overlap with the substrate support 11a when viewed from above (see Figure 2). This allows the dummy substrate 120 to be placed on the dummy substrate support 112. That is, the dummy substrate 120 can be placed on the substrate W placed on the substrate support 11a via a desired shielding plate height H1. In this case, the space between the substrate W and the dummy substrate 120 is open on the sides, allowing active species such as ions generated by the plasma to wrap around the dummy substrate 120 and reach the substrate W.

[0037] Furthermore, the shaft portion 111 and / or the dummy substrate support portion 112 may be made of, for example, quartz, metal, ceramics, or the like.

[0038] Furthermore, the mounting base 11 and the dummy circuit board 120 supported by the dummy circuit board support mechanism 110 are not electrically connected. That is, the dummy circuit board 120 supported by the dummy circuit board support mechanism 110 is electrically isolated. For example, the shaft portion 111 and / or the dummy circuit board support portion 112 may be made of an insulating material.

[0039] The dummy substrate 120 is, for example, a substrate with the same diameter as substrate W. The radial size (diameter) of the dummy substrate 120 may be larger than that of substrate W. Furthermore, the dummy substrate 120 is, for example, a substrate with the same thickness as substrate W. The thickness of the dummy substrate 120 may be thicker or thinner than that of substrate W. Also, the dummy substrate 120 is, for example, a substrate made of silicon. However, the material of the dummy substrate 120 is not limited to this.

[0040] [Substrate Processing Method] Next, an example of a substrate processing method will be explained using Figures 3 and 4. Figure 3 is an example of a flowchart showing a substrate processing method. Figure 4 is an example of a schematic cross-sectional view showing the structure of the substrate W after substrate processing.

[0041] In step S101, the substrate W is placed on the substrate support portion 11a. For example, the control device 130 controls the rotation mechanism of the dummy substrate support mechanism 110 to set the dummy substrate support portion 112 to the first state. Next, the control device 130 opens the gate valve 18. Next, the control device 130 controls a transfer device (not shown) to transfer the substrate W into the processing container 10 from the loading / unloading port 17 and dispose it above the substrate support portion 11a. The control device 130 raises a lift pin (not shown) protruding from the substrate support portion 11a, and the lift pin contacts the lower surface (back surface) of the substrate W to support the substrate W. After the transfer device retreats from the loading / unloading port 17, the control device 130 closes the gate valve 18. Then, the control device 130 lowers the lift pin (not shown) to place the substrate W on the substrate support portion 11a.

[0042] Here, the substrate W in step S101 has a base material 400 and an underlayer film 410 (see FIG. 4 described later).

[0043] In step S102, the dummy substrate 120 is placed on the dummy substrate support portion 112. For example, the control device 130 controls the rotation mechanism of the dummy substrate support mechanism 110 to set the dummy substrate support portion 112 to the second state. Next, the control device 130 opens the gate valve 18. Next, the control device 130 controls a transfer device (not shown) to transfer the dummy substrate 120 into the processing container 10 from the loading / unloading port 17 and dispose it above the substrate support portion 11a (above the substrate W). The control device 130 controls the lifting mechanism of the dummy substrate support mechanism 110 to raise the shaft portion 111, and the dummy substrate support portion 112 contacts the lower surface (back surface) of the dummy substrate 120 to support the dummy substrate 120. After the transfer device retreats from the loading / unloading port 17, the control device 130 closes the gate valve 18. Then, the control device 130 controls the lifting mechanism of the dummy substrate support mechanism 110 to lower the shaft portion 111 and adjusts the shielding plate height H1 between the substrate W and the dummy substrate 120 to a predetermined height.

[0044] Here, the dummy substrate 120 is disposed between the lower surface of the top wall 10a and the upper surface of the substrate W. Also, the dummy substrate 120 is disposed closer to the substrate W side (lower side) than the intermediate position between the lower surface of the top wall 10a and the upper surface of the substrate W. In other words, the distance from the upper surface of the substrate W to the lower surface of the dummy substrate 120 (shielding plate height H1) is shorter than the distance from the lower surface of the top wall 10a to the upper surface of the dummy substrate 120 (height H2).

[0045] Specifically, the shielding plate height H1 from the upper surface of the substrate W to the lower surface of the dummy substrate 120 is preferably within a range of, for example, 0.5 [mm] to 10 [mm].

[0046] Also, the shielding plate height H1 from the upper surface of the substrate W to the lower surface of the dummy substrate 120 is preferably shorter than the length of the mean free path of the active species (ions) of the plasma generated in step S103 described later.

[0047] In step S103, a target film 420 is formed on the substrate W. For example, the control device 130 controls the exhaust device 16 to control the inside of the processing vessel 10 to a predetermined pressure. The predetermined pressure is preferably within a range of, for example, 3 [Pa] to 13 [Pa]. Also, the control device 130 controls the gas supply unit 83 to supply a processing gas (film-forming gas) into the processing vessel 10. Further, the control device 130 controls the microwave output unit 30 to generate a plasma of the processing gas in the processing vessel 10. Thereby, the substrate W and the dummy substrate 120 are exposed to the plasma of the processing gas, and as shown in FIG. 4, the target film 420 is formed on the underlying film 410.

[0048] When the target film 420 is a graphene film, for example, a hydrocarbon gas and a plasma-exciting gas (argon gas) are supplied as the processing gas. When the target film 420 is a hexagonal boron nitride (h-BN) film, for example, a boron-containing gas, a nitrogen-containing gas, and a plasma-exciting gas (argon gas) are supplied as the processing gas.

[0049] In step S104, the dummy substrate 120 is carried out.

[0050] In step S105, the substrate W is carried out.

[0051] Note that the control from step S104 to step S105 can be performed by reversing the procedure of the control from step S101 to step S102, so redundant explanations are omitted.

[0052] As described above, by placing the dummy substrate 120 on the side of the substrate W (below) rather than at an intermediate position between the lower surface of the top wall 10a and the upper surface of the substrate W, and covering the substrate W, the amount of ions reaching the substrate W is suppressed. This suppresses damage to the substrate W. In other words, it is possible to deposit the target film 420 on the underlayment film 410 while suppressing damage to the underlayment film 410 formed on the substrate W.

[0053] [Damage Evaluation of Underlayment Film 410] Next, the damage to the underlayment film 410 when the target film 420 is deposited is evaluated. Here, the damage to the underlayment film 410 (Low-k film) is evaluated using a Fourier transform infrared spectrophotometer (FTIR). Here, the underlayment film 410 (Low-k film) is an organic film, CH ３ It has a group. CH ３ The wavenumber of the antisymmetric stretching is 2955 [cm] －１ ]. When the base film 410 is damaged by the plasma during the deposition of the target film 420, CH ３ The peak intensity of the antisymmetric stretching decreases. In the following explanation, CH ３ The damage to the substrate film 410 is evaluated by comparing the peak intensities of the antisymmetric stretching.

[0054] Figure 5 is an example of a graph used to evaluate damage to the undercoat 410. The vertical axis represents CH ３ This shows the peak intensity of the antisymmetric stretching.

[0055] (a) shows the peak intensity of the base film 410 before the target film 420 is deposited (Initial). (b) shows the peak intensity of the base film 410 when the target film 420 is deposited without a dummy substrate (shielding plate) 120 and at a pressure of 3 [Pa] inside the processing container 10 (no shielding plate, 3 Pa). (c) shows the peak intensity of the base film 410 when the target film 420 is deposited without a dummy substrate (shielding plate) 120 and at a pressure of 13 [Pa] inside the processing container 10 (no shielding plate, 13 Pa). (d) shows the peak intensity of the base film 410 when the target film 420 is deposited with a dummy substrate (shielding plate) 120 and at a pressure of 3 [Pa] inside the processing container 10 (with shielding plate, 3 Pa). (e) shows the peak intensity of the underlayer film 410 when a dummy substrate (shielding plate) 120 is present and the target film 420 is deposited at a pressure of 13 [Pa] inside the processing container 10 (shielding plate present, 13 Pa). In (d) and (e), the height H1 of the shielding plate is 0.5 [mm].

[0056] As shown in comparison with (a) before the deposition of the target film 420 without the dummy substrate (shielding plate) 120, (b) and (c) show a decrease in peak intensity, indicating that the underlying film 410 has been damaged by the plasma.

[0057] In contrast, (d) and (e), after depositing the target film 420 with the dummy substrate (shielding plate) 120, show a suppressed reduction in peak intensity, as can be seen in comparison with (b) and (c), after depositing the target film 420 without the dummy substrate (shielding plate) 120, thus suppressing damage to the underlying film 410 by the plasma. In this way, by placing the dummy substrate 120 on the substrate W with a shielding plate height H1, damage to the underlying film 410 when depositing the target film 420 using plasma is suppressed.

[0058] Figure 6 is an example of a graph used to evaluate damage to the undercoat 410. The horizontal axis represents the shielding plate height [mm]. The vertical axis represents CH ３ This shows the peak intensity of the antisymmetric stretching. Here, the peak intensity of the underlayer film 410 is shown when a dummy substrate (shielding plate) 120 is present and the target film 420 is formed at a pressure of 3 [Pa] inside the processing container 10 (shielding plate present, 3 Pa).

[0059] As shown in Figure 6, by setting the shielding plate height H1 to a range of 0.5 [mm] to 10 [mm], more preferably within a range of 0.5 [mm] to 5 [mm], damage to the underlayer film 410 by plasma is suppressed. In this way, by placing the dummy substrate 120 on the substrate W with a shielding plate height H1, damage to the underlayer film 410 when the target film 420 is deposited using plasma is suppressed.

[0060] Figure 7 is an example of a schematic diagram illustrating ion acceleration.

[0061] When microwaves are emitted from the microwave emission mechanism 42, plasma 700 is generated inside the processing container 10. Also, due to the mass difference between electrons and ions, electrons 710 reach the substrate W before ions, creating a difference in potential 800 between the plasma 700 and the substrate W. In addition, a sheath 750 is formed near the surface of the substrate W. Ions 720 that reach the sheath 750 are accelerated by the difference in potential 800 and collide with the substrate W.

[0062] Damage to the substrate W (underlying film 410) is caused by the energy from ion collisions. In other words, the more ions that reach the substrate W (underlying film 410), the greater the damage to the substrate W (underlying film 410).

[0063] Figure 8 is an example of a schematic diagram illustrating ion acceleration at low pressure. Figure 9 is an example of a schematic diagram illustrating ion acceleration at high pressure.

[0064] As shown in Figure 8, at low pressure, the plasma density is low, but the mean free path of ions 720 is long, and the distance they can reach the substrate W (indicated by arrows in Figure 8) is long. Conversely, as shown in Figure 9, at high pressure, the plasma density is high, but the mean free path of ions 720 is short, and the distance they can reach the substrate W (indicated by arrows in Figure 9) is short. For this reason, the amount of ions reaching the substrate W is approximately equal at low pressure (see Figure 8) and high pressure (see Figure 9).

[0065] However, at low pressure, the electron temperature (velocity) is high, and the sheath potential is large. Therefore, even if the amount of ions reaching the substrate W is almost the same at low pressure (see Figure 8) and high pressure (see Figure 9), the collision velocity of ions 720 with the substrate W is greater at low pressure (see Figure 8) compared to high pressure (see Figure 9). Consequently, the damage to the substrate W (undercoat 410) is greater at low pressure (see Figure 8) compared to high pressure (see Figure 9).

[0066] Figure 10 is an example of a schematic diagram illustrating ion acceleration at low pressure when the dummy substrate 120 is grounded. Figure 11 is an example of a schematic diagram illustrating ion acceleration at high pressure when the dummy substrate 120 is grounded.

[0067] As shown in Figure 10, by placing the dummy substrate 120, ions 721 are shielded, and ions 722 reach the substrate W. In this way, by placing the dummy substrate 120, the amount of ions reaching the substrate is directly suppressed. Therefore, damage to the substrate W (undercoat 410) is also suppressed.

[0068] Furthermore, as shown in Figure 11, even under high pressure, the movement of ions 723 towards the substrate W is suppressed by ions above the dummy substrate 120 colliding with ions 723, thereby indirectly preventing them from reaching the substrate W, and thus suppressing damage to the substrate W (undercoat 410).

[0069] Furthermore, it is preferable that the shielding plate height H1 on which the dummy substrate 120 is placed is shorter than the mean free path length. This directly suppresses the amount of ions reaching the substrate W and also suppresses damage to the substrate W (underlayment 410). For example, at 3 Pa and 300°C, the mean free path length of argon (Ar) is approximately 5.2 mm. For example, at 13 Pa and 300°C, the mean free path length of argon (Ar) is approximately 1.2 mm.

[0070] The above describes a method for forming a target film 420 using the plasma processing apparatus 1 according to one embodiment. However, this disclosure is not limited to the above embodiment, and various modifications and improvements are possible within the scope of the gist of this disclosure as described in the claims.

[0071] H1 Shielding plate height (spacing) W Substrate 410 Undercoat 420 Target film 1 Plasma processing device 2 Plasma source 10 Processing container 10a Top wall 10b Side wall 11 Mounting platform 11a Substrate support section (substrate mounting section) 16 Exhaust device 23 Gas shower section 30 Microwave output section 40 Microwave transmission section 83 Gas supply section 110 Dummy substrate support mechanism 111 Shaft section 112 Dummy substrate support section 120 Dummy substrate (shielding plate) 130 Control device (control section)

Claims

1. A substrate processing method comprising the steps of: placing a substrate having a base film on a substrate support portion of a mounting table; placing a dummy substrate on a dummy substrate support portion at a position higher than the position of the substrate so as to shield the substrate; and supplying a processing gas into a processing container to generate plasma of the processing gas, exposing the substrate and the dummy substrate to the plasma, and forming a target film on the base film, wherein the dummy substrate is positioned on the side of the substrate that is more than an intermediate position between the lower surface of the top wall of the processing container and the upper surface of the substrate.

2. The substrate processing method according to claim 1, wherein the distance from the upper surface of the substrate to the lower surface of the dummy substrate is shorter than the mean free path length of the active species of the plasma.

3. The substrate processing method according to claim 1, wherein the distance from the upper surface of the substrate to the lower surface of the dummy substrate is within the range of 0.5 mm to 10 mm.

4. The substrate processing method according to claim 1, wherein in the step of forming the target film, the pressure inside the processing vessel is in the range of 3 Pa to 13 Pa.

5. The substrate processing method according to claim 1, wherein the undercoat is a low-k film.

6. The substrate processing method according to claim 1, wherein the target film is a graphene film.

7. The substrate processing method according to claim 1, wherein the target film is a hexagonal boron nitride film.

8. The substrate processing method according to claim 6, wherein the processing gas includes a hydrocarbon gas.

9. The substrate processing method according to claim 7, wherein the processing gas includes a boron-containing gas.

10. The substrate processing method according to claim 7, wherein the processing gas further comprises a nitrogen-containing gas.

11. The substrate processing method according to any one of claims 7 to 10, wherein the processing gas includes an inert gas.

12. The substrate processing method according to claim 11, wherein the inert gas is argon gas or helium gas.

13. The substrate processing method according to claim 2, wherein the processing gas contains argon gas, the active species of the plasma is argon ions, and the distance from the upper surface of the substrate to the lower surface of the dummy substrate is shorter than the mean free path length of the argon ions.

14. The substrate processing method according to claim 1, wherein the plasma is a microwave plasma.

15. A substrate processing apparatus comprising: a processing container; a mounting table provided in the processing container and having a substrate support portion for supporting a substrate; a dummy substrate support mechanism provided in the processing container and having a dummy substrate support portion for supporting a dummy substrate at a position higher than the position of the substrate so as to shield the substrate; a plasma source for generating plasma in the processing container; and a control unit, wherein the control unit comprises the steps of: placing the substrate having a base film on the substrate support portion of the mounting table; placing the dummy substrate on the dummy substrate support portion so as to shield the substrate at a position higher than the position of the substrate; and supplying a processing gas into the processing container to generate plasma of the processing gas, exposing the substrate and the dummy substrate to the plasma, and forming a target film on the base film, wherein the dummy substrate is positioned on the side of the substrate that is more than an intermediate position between the lower surface of the top wall of the processing container and the upper surface of the substrate.

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