Patent Publication Number: US-2021164103-A1

Title: Film forming method and processing apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2019-218515, filed on Dec. 3, 2019, the entire contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a film forming method and a processing apparatus. 
     BACKGROUND 
     Conventionally, there is a technique for forming a carbon-containing film on a substrate to be processed (hereinafter, also referred to as a “wafer”) using a plasma chemical vapor deposition (CVD) method. 
     PRIOR ART DOCUMENT 
     Patent Document 
     
         
         Patent Document 1: Japanese Laid-Open Patent Publication No. 2014-167142 
       
    
     SUMMARY 
     According to one embodiment of the present disclosure, there is provided a film forming method of forming a carbon-containing film by microwave plasma from a microwave source. The film forming method includes: a dummy step of performing a dummy process by generating plasma of a first carbon-containing gas within a processing container; a placement step of placing a substrate on a stage within the processing container; and a film forming step of forming a carbon-containing film on the substrate using plasma of a second carbon-containing gas 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the present disclosure. 
         FIG. 1  is a view illustrating an example of a processing apparatus according to an embodiment of the present disclosure. 
         FIG. 2  is a view illustrating an example of a configuration of a microwave introduction device according to the present embodiment. 
         FIG. 3  is a view illustrating an example of a microwave radiation mechanism according to the present embodiment. 
         FIG. 4  is a view schematically illustrating an example of a ceiling wall portion of a processing container according to the present embodiment. 
         FIG. 5  is a flowchart illustrating an example of a film formation process according to the present embodiment. 
         FIG. 6  is a view illustrating a detailed example of a dummy step and a film forming step according to the present embodiment. 
         FIG. 7  is a graph illustrating an example of in-plane film thickness distribution of wafers subjected to continuous film formation according to the present embodiment. 
         FIG. 8  is a view illustrating an example of in-plane film thickness distribution of wafers subjected to continuous film formation according to the present embodiment. 
         FIG. 9  is a graph illustrating an example of in-plane film thickness distribution of wafers subjected to continuous film formation in a comparative example. 
         FIG. 10  is a view illustrating an example of in-plane film thickness distribution of wafers subjected to continuous film formation in the comparative example. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, embodiments of a film forming method and a processing apparatus disclosed herein will be described in detail with reference to the drawings. The technology disclosed herein is not limited by the following embodiments. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, systems, and components have not been described in detail so as not to unnecessarily obscure aspects of the various embodiments. 
     When continuously forming a graphene film as a carbon-containing film on a plurality of wafers, it is required to improve inter-wafer stability and a processing capacity of the film formation process. It is known that a plasma CVD method includes performing a pre-coating in order to improve the inter-wafer stability when film formation is continuously performed on a plurality of wafers. However, when forming a graphene film on the wafer, carbon on the inner wall of a processing container (hereinafter, also referred to as a “chamber”) is etched by hydrogen introduced for controlling the formation of the graphene film, which changes the condition of the chamber. As a result, when a graphene film is continuously formed, the in-plane film thickness distribution becomes non-uniform between the wafers. Therefore, it is desired to improve the film thickness uniformity between wafers in continuous film formation. 
     [Configuration of Substrate Processing Apparatus  100 ] 
       FIG. 1  is a view illustrating an example of a processing apparatus according to an embodiment of the present disclosure. The processing apparatus  100  illustrated in  FIG. 1  includes a processing container  101 , a stage  102 , a gas supply mechanism  103 , an exhaust device  104 , a microwave introduction device  105 , and a controller  106 . The processing container  101  accommodates a wafer W. The wafer W is placed on the stage  102 . The gas supply mechanism  103  supplies gases into the processing container  101 . The exhaust device  104  exhausts the interior of the processing container  101 . The microwave introduction device  105  generates microwaves for generating plasma inside the processing container  101  and introduces the microwaves into the processing container  101 . The controller  106  controls the operation of each part of the processing apparatus  100 . 
     The processing container  101  is formed of a metallic material, such as aluminum or an alloy thereof, has a substantially cylindrical shape, and has a plate-shaped ceiling wall portion  111 , a bottom wall portion  113 , and a side wall portion  112  connecting the ceiling wall portion  111  and the bottom wall portion  113 . The microwave introduction device  105  is provided above the processing container  101 , and functions as a plasma generator that introduces electromagnetic waves (microwaves) into the processing container  101  so as to generate plasma. The microwave introduction device  105  will be described in detail later. 
     The ceiling wall portion  111  has a plurality of openings into which a microwave radiation mechanism and a gas introduction part (to be described later) of the microwave introduction device  105  are fitted. The side wall portion  112  has a loading/unloading port  114  for loading/unloading the wafer W therethrough, which is a substrate to be processed, into/from a transfer chamber (not illustrated) provided adjacent to the processing container  101 . The loading/unloading port  114  is opened/closed by a gate valve  115 . The exhaust device  104  is provided on the bottom wall portion  113 . The exhaust device  104  is connected to an exhaust pipe  116  connected to the bottom wall portion  113 , and includes a vacuum pump and a pressure control valve. The interior of the processing container  101  is exhausted through the exhaust pipe  116  by the vacuum pump of the exhaust device  104 . An internal pressure of the processing container  101  is controlled by the pressure control valve. 
     The stage  102  has a disc shape and is made of ceramic, such as AlN. The stage  102  is supported by a support member  120  made of ceramic such as AlN and extending upward from the center of the bottom of the processing container  101 . A guide ring  181  is provided on the outer edge portion of the stage  102  so as to guide the wafer W. In addition, lifting pins (not illustrated) for raising/lowering the wafer W are provided inside the stage  102  so as to be moved upward and downward with respect to the upper surface of the stage  102 . A resistance heater  182  is embedded in the stage  102 . The heater  182  heats the wafer W on the stage  102  through the stage  102  based on power provided from a heater power supply  183 . A thermocouple (not illustrated) is inserted into the stage  102 . The stage  102  is configured to be capable of controlling a heating temperature of the wafer W to a predetermined temperature in a range of, for example, 300 to 1,000 degrees C., based on a signal from the thermocouple. Further, an electrode  184  having a size similar to that of the wafer W is embedded above the heater  182  inside the stage  102 . A high-frequency bias power supply  122  is electrically connected to the electrode  184 . A high-frequency bias for attracting ions is applied from the high-frequency bias power supply  122  to the stage  102 . The high-frequency bias power supply  122  may be omitted depending on the characteristics of plasma processing. 
     The gas supply mechanism  103  is provided to introduce a plasma-generating gas and a raw material gas for forming a carbon-containing film (a graphene film) into the processing container  101 , and has a plurality of gas introduction nozzles  123  provided therein. Each gas introduction nozzle  123  is fitted into a respective opening portion formed in the ceiling wall portion  111  of the processing container  101 . A gas supply pipe  191  is connected to the gas introduction nozzles  123 . The gas supply pipe  191  is branched into five branch pipes  191   a ,  191   b ,  191   c ,  191   d , and  191   e . An Ar gas source  192 , an O 2  gas source  193 , a N 2  gas source  194 , a H 2  gas source  195 , and a C 2 H 2  gas source  196  are connected to the branch pipes  191   a ,  191   b ,  191   c ,  191   d , and  191   e , respectively. The Ar gas source  192  supplies an Ar gas as a noble gas, which is a plasma-generating gas. In addition to the Ar gas, for example, a He gas, a Ne gas, a Kr gas, a Xe gas, or the like may be used as the noble gas. Among these, the Ar gas capable of stably generating plasma is preferable. The O 2  gas source  193  supplies an O 2  gas as an oxidation gas, which is a cleaning gas. The N 2  gas source  194  supplies a N 2  gas used as, for example, a purge gas. The H 2  gas source  195  supplies a H 2  gas as a reducing gas. The C 2 H 2  gas source  196  supplies an acetylene (C 2 H 2 ) gas as a carbon-containing gas, which is a film-forming raw material gas. The C 2 H 2  gas source  196  may supply a different carbon-containing gas. For example, ethylene (C 2 H 4 ), methane (CH 4 ), ethane (C 2 H 6 ), propane (C 3 H 8 ), propylene (C 3 H 6 ), methanol (CH 3 OH), ethanol (C 2 H 5 OH), or the like may be used. The carbon-containing gas supplied by the C 2 H 2  gas source  196  is a gas contained in a first carbon-containing gas and a second carbon-containing gas, which will be described later. That is, in the present embodiment, the same carbon-containing gas is used as the gas contained in the first carbon-containing gas and the gas contained the second carbon-containing gas. Further, as the gas contained in the first carbon-containing gas and the gas contained in the second carbon-containing gas, different carbon-containing gases such as acetylene and ethylene may be used. 
     Although not illustrated, each of the branch pipes  191   a ,  191   b ,  191   c ,  191   d , and  191   e  is provided with a mass flow controller for controlling a flow rate and valves provided on front and back sides of the mass flow controller. It is also possible to adjust the dissociation of gas by providing a shower plate and supplying the C 2 H 2  gas and the H 2  gas to a position close to the wafer W. The same effect can also be obtained by extending the nozzles for supplying these gases downward. 
     As described above, the microwave introduction device  105  is provided above the processing container  101 , and functions as a plasma generator that introduces electromagnetic waves (microwaves) into the processing container  101  so as to generate plasma. 
       FIG. 2  is a view illustrating an example of a configuration of the microwave introduction device according to the present embodiment. As illustrated in  FIGS. 1 and 2 , the microwave introduction device  105  includes the ceiling wall portion  111  of the processing container  101 , a microwave output part  130 , and an antenna unit  140 . The ceiling wall portion  111  functions as a ceiling plate. The microwave output part  130  generates microwaves, and distributes and outputs the microwaves to a plurality of paths. The antenna unit  140  introduces the microwaves output from the microwave output part  130  into the processing container  101 . 
     The microwave output part  130  has a microwave power supply  131 , a microwave oscillator  132 , an amplifier  133 , and a distributor  134 . The microwave oscillator  132  is a solid-state, and oscillates the microwaves, for example, at 860 MHz (e.g., PLL oscillation). The frequency of the microwaves is not limited to 860 MHz, and may be a frequency in a range of 700 MHz to 10 GHz, such as 2.45 GHz, 8.35 GHz, 5.8 GHz, 1.98 GHz, or the like. The amplifier  133  amplifies the microwaves oscillated by the microwave oscillator  132 . The distributor  134  distributes the microwaves amplified by the amplifier  133  to the plurality of paths. The distributor  134  distributes the microwaves while matching impedances on the input side and the output side. 
     The antenna unit  140  includes a plurality of antenna modules  141 . Each of the antenna modules  141  introduces the microwaves distributed by the distributor  134  into the processing container  101 . The configurations of all of the antenna modules  141  are the same. Each antenna module  141  has an amplifier part  142  configured mainly to amplify and output the distributed microwaves, and a microwave radiation mechanism  143  configured to radiate, into the processing container  101 , the microwaves output from the amplifier part  142 . 
     The amplifier part  142  has a phase shifter  145 , a variable gain amplifier  146 , a main amplifier  147 , and an isolator  148 . The phase shifter  145  changes a phase of the microwaves. The variable gain amplifier  146  adjusts a power level of the microwaves input to the main amplifier  147 . The main amplifier  147  is configured as a solid-state amplifier. The isolator  148  separates reflected microwaves, which are reflected at an antenna part of the microwave radiation mechanism  143  (to be described later) and are directed toward the main amplifier  147 . 
     Here, the microwave radiation mechanism  143  will be described with reference to  FIG. 3 .  FIG. 3  is a view schematically illustrating an example of the microwave radiation mechanism according to the present embodiment. As illustrated in  FIG. 1 , a plurality of microwave radiation mechanisms  143  are provided on the ceiling wall portion  111 . As illustrated in  FIG. 3 , each microwave radiation mechanism  143  has a cylindrical outer conductor  152  and an inner conductor  153  provided within the outer conductor  152  in a coaxial relationship with the outer conductor  152 . The microwave radiation mechanism  143  includes a coaxial tube  151  having a microwave transmission path provided between the outer conductor  152  and the inner conductor  153 , a tuner  154 , a power-feeding part  155 , and an antenna part  156 . The tuner  154  matches the impedance of a load with the characteristic impedance of the microwave power supply  131 . The power-feeding part  155  feeds the microwaves amplified by the amplifier part  142  to the microwave transmission path. The antenna part  156  radiates the microwaves from the coaxial tube  151  into the processing container  101 . 
     The microwaves amplified by the amplifier part  142  are introduced from the side of the upper end portion of the outer conductor  152  into the power-feeding part  155  through the coaxial cable. The microwaves are radiated by, for example, a power-feeding antenna. By the radiation of the microwaves, the microwave power is fed to the microwave transmission path between the outer conductor  152  and the inner conductor  153 . The microwave power propagates toward the antenna part  156 . 
     The antenna part  156  is provided at the lower end portion of the coaxial tube  151 . The antenna part  156  includes a disc-shaped planar antenna  161  connected to the lower end portion of the inner conductor  153 , a slow-wave material  162  disposed on the upper surface side of the planar antenna  161 , and a microwave transmission plate  163  disposed on the bottom surface side of the planar antenna  161 . The microwave transmission plate  163  is fitted into the ceiling wall portion  111 . The bottom surface of the microwave transmission plate  163  is exposed to the internal space of the processing container  101 . The planar antenna  161  has slots  161   a  formed to penetrate through the planar antenna  161 . The shape of each slot  161   a  is appropriately set such that the microwaves are efficiently radiated. A dielectric material may be inserted into each slot  161   a.    
     The slow-wave material  162  is formed of a material having a dielectric constant higher than a vacuum. The phase of the microwaves may be adjusted based on the thickness of the slow-wave material  162  such that the radiation energy of the microwaves is maximized. The microwave transmission plate  163  is also made of a dielectric material, and has a shape capable of efficiently radiating the microwaves in a TE mode. Then, the microwaves transmitted through the microwave transmission plate  163  generate plasma in the internal space of the processing container  101 . As a material for constituting the slow-wave material  162  and the microwave transmission plate  163 , for example, quartz, ceramic, or a fluorine-based resin such as a polytetrafluoroethylene resin, a polyimide resin, or the like may be used. 
     The tuner  154  constitutes a slug tuner. As illustrated in  FIG. 3 , the tuner  154  has slugs  171   a  and  171   b , an actuator  172 , and a tuner controller  173 . The slugs  171   a  and  171   b  are two slugs arranged on the base end side (upper end side) of the coaxial tube  151  with respect to the antenna part  156 . The actuator  172  drives these two slugs independently of each other. The tuner controller  173  controls the actuator  172 . 
     The slugs  171   a  and  171   b  have a plate shape and an annular shape, are made of a dielectric material such as ceramic, and are arranged between the outer conductor  152  and the inner conductor  153  of the coaxial tube  151 . Further, the actuator  172  individually drives each of the slugs  171   a  and  171   b , for example, by rotating two screws provided inside the inner conductor  153  and screwed to the slugs  171   a  and  171   b , respectively. Then, based on a command from the tuner controller  173 , the actuator  172  moves the slugs  171   a  and  171   b  in the vertical direction. The tuner controller  173  adjusts the positions of the slugs  171   a  and  171   b  such that the impedance at the terminal end portion becomes 50Ω. 
     The main amplifier  147 , the tuner  154 , and the planar antenna  161  are arranged close to one another. The tuner  154  and the planar antenna  161  constitute a lumped constant circuit, and also function as a resonator. An impedance mismatch exists in the mounting portion of the planar antenna  161 . However, since the tuner  154  directly tunes the plasma load, the plasma load including plasma may be tuned with high precision. Thus, it is possible to eliminate the influence of reflection on the planar antenna  161 . 
       FIG. 4  is a view schematically illustrating an example of the ceiling wall portion of the processing container according to the present embodiment. As illustrated in  FIG. 4 , in the present embodiment, seven microwave radiation mechanisms  143  are provided. Microwave transmission plates  163  corresponding to the seven microwave radiation mechanisms  143  are arranged so as to be evenly arranged in a closely packed hexagonal structure. That is, one of the seven microwave transmission plates  163  is arranged at the center of the ceiling wall portion  111 , and the other six microwave transmission plates  163  are arranged around the center. These seven microwave transmission plates  163  are arranged such that adjacent microwave transmission plates  163  are evenly spaced apart from one another. In addition, the plurality of gas introduction nozzles  123  of the gas supply mechanism  103  are arranged so as to surround the periphery of the central microwave transmission plate  163 . The number of microwave radiation mechanisms  143  is not limited to seven. 
     The controller  106  is typically configured with a computer, and controls each part of the processing apparatus  100 . The controller  106  includes, for example, a storage part, which stores a process sequence of the processing apparatus  100  and process recipes that are control parameters, an input part, a display and the like, and is capable of performing a predetermined control according to a selected process recipe. 
     For example, the controller  106  controls each part of the processing apparatus  100  so as to perform a film forming method to be described later. As a detailed example, the controller  106  executes a dummy step of performing a dummy process (dummy film formation) by generating plasma of the first carbon-containing gas in the state in which a dummy substrate (a dummy wafer) is placed on the stage  102  of the processing container  101 . The controller  106  executes a placement step of placing the substrate (the wafer W) on the stage  102  of the processing container  101 . The controller  106  executes a film forming step of forming a carbon-containing film on the substrate (the wafer W) using plasma of the second carbon-containing gas. Here, as the first carbon-containing gas, the acetylene (C 2 H 2 ) gas supplied from the C 2 H 2  gas source  196  may be used. As the first carbon-containing gas, for example, an ethylene (C 2 H 4 ) gas, a methane (CH 4 ) gas, an ethane (C 2 H 6 ) gas, a propane (C 3 H 8 ) gas, a propylene (C 3 H 6 ) gas, a methanol (CH 3 OH) gas, an ethanol (C 2 H 5 OH) gas, or the like may be used. As the second carbon-containing gas, a mixed gas of the H 2  gas supplied from the H 2  gas source  195  and the acetylene (C 2 H 2 ) gas supplied from the C 2 H 2  gas source  196  may be used. As the second carbon-containing gas, for example, a mixed gas containing the H 2  gas, and one of the ethylene (C 2 H 4 ) gas, the methane (CH 4 ) gas, the ethane (C 2 H 6 ) gas, the propane (C 3 H 8 ) gas, the propylene (C 3 H 6 ) gas, the methanol (CH 3 OH) gas, and the ethanol (C 2 H 5 OH) gas may be used. 
     [Film Forming Method] 
     First, the film forming method according to the present embodiment will be described.  FIG. 5  is a flowchart illustrating an example of the film formation process according to the present embodiment.  FIG. 6  is a view illustrating detailed examples of the dummy step and the film forming step according to the present embodiment. In  FIG. 6 , the same step numbers are used to compare the dummy step and the film forming step. 
     In the film forming method according to the present embodiment, first, the controller  106  executes the dummy step (step S 1 ). In the dummy step, the controller  106  places a dummy wafer on the stage  102  of the processing container  101 . Next, the controller  106  reduces an internal pressure of the processing container  101  to a first pressure (e.g., 0.4 Torr). The controller  106  supplies the Ar/H 2  gas, which is a plasma-generating gas, to the processing container  101  from the gas introduction nozzles  123 . The controller  106  causes the microwaves, which are distributed into the plurality of paths and output from the microwave output part  130  of the microwave introduction device  105 , to be guided into the plurality of antenna modules  141  of the antenna unit  140 , and to be radiated from the microwave radiation mechanism  143  so as to ignite plasma. 
     In each antenna module  141 , the microwaves are individually amplified by the main amplifier  147  constituting a solid-state amplifier, are fed to each microwave radiation mechanism  143 , and reach the antenna part  156  through the coaxial tube  151 . At that time, the impedance of microwaves is automatically matched by the slugs  171   a  and  171   b  of the tuner  154 . In a state in which there is substantially no power reflection, the microwaves pass from the tuner  154  through the slow-wave material  162  of the antenna part  156 , and are radiated from the slots  161   a  of the planar antenna  161 . The microwaves further pass through the microwave transmission plate  163  and are transmitted to the front surface (bottom surface) of the microwave transmission plate  163  which is in contact with the plasma so as to form surface waves. The electric power from each antenna part  156  is spatially synthesized inside the processing container  101  so that surface wave plasma is generated by the Ar/H 2  gas in a region directly below the ceiling wall portion  111 . This region is defined as a plasma generation region. 
     Here, details of the dummy step will be described with reference to  FIG. 6 . As illustrated in  FIG. 6 , the controller  106  executes pretreatment (pre-processing) with plasma of the Ar/H 2  gas on the surface of the dummy wafer for a predetermined time (e.g., 10 minutes) (step S 11 : dummy). In the description of step S 11  in  FIG. 6 , Ar is omitted. 
     Specifically, the controller  106  controls each part of the processing apparatus  100  such that the pretreatment is performed under, for example, the following processing conditions. 
     &lt;Pretreatment of Dummy Step&gt; 
     Microwave power: 100 to 3,850 W (more preferably, 1,000 to 3,500 W) 
     Internal pressure of processing container  101 : 0.02 to 10 Torr (26.6 to 1,333 Pa) 
     Processing gas: Ar/H 2 =0 to 3,000 sccm/l to 3,000 sccm 
     Temperature of dummy wafer: 300 to 700 degrees C. 
     Processing time: 5.0 seconds to 60 minutes 
     When the pretreatment is completed, the controller  106  starts supplying the Ar/H 2  gas, which is a plasma-generating gas in plasma CVD, from the gas introduction nozzles  123  (step S 12 : dummy). The controller  106  controls the microwave introduction device  105  to ignite the plasma, as in the case of the pretreatment (step S 13 : dummy). The controller  106  reduces the internal pressure of the processing container  101  to a second pressure (e.g., 0.05 Torr) (step S 14 : dummy) In addition, steps S 12  to S 14  are steps of stabilizing the gas, the pressure, and the plasma before the plasma CVD. 
     The controller  106  starts supplying the first carbon-containing gas (the C 2 H 2  gas), which is a precursor of the plasma CVD, from the gas introduction nozzles  123  into the processing container  101  (step S 15 : dummy). These gases are excited and dissociated by the plasma, radicals from which ions and electrons are removed are supplied to the dummy wafer, and thus a carbon-containing film (a graphene film) is formed on the dummy wafer. In the dummy step, the carbon-containing film is also formed on the inner wall of the processing container  101 . The controller  106  unloads the dummy wafer for which the film formation is completed. 
     Specifically, the controller  106  controls each part of the processing apparatus  100  such that the plasma CVD is performed under, for example, the following processing conditions. 
     &lt;Plasma CVD of Dummy Step&gt; 
     Microwave power: 100 to 3,850 W (more preferably, 1,000 to 3,500 W) 
     Internal pressure of processing container  101 : 0.01 to 5 Torr (1.33 to 667 Pa) 
     Processing gas: C 2 H 2  gas=0.1 to 100 sccm
         H 2 =0.1 to 500 sccm   Ar=0.1 to 3,000 sccm       

     Temperature of dummy wafer: 300 to 700 degrees C. 
     Processing time: 5.0 seconds to 60 minutes 
     Descriptions will be made referring back to  FIG. 5 . The controller  106  places the wafer W on the stage  102  of the processing container  101  (step S 2 ). The controller  106  executes the film forming step (step S 3 ). The controller  106  reduces the internal pressure of the processing container  101  to the first pressure (e.g., 0.4 Torr). 
     Next, details of the film forming step will be described with reference to  FIG. 6 . As illustrated in  FIG. 6 , the controller  106  supplies the Ar/H 2  gas into the processing container  101 , and performs an annealing-based pretreatment on the surface of the wafer W for a predetermined time (e.g., 5 minutes) (step S 11 : film formation). In the description of step S 11  in  FIG. 6 , Ar is omitted. In the pretreatment of the film forming step, the annealing is used in order to suppress etching of the carbon-containing film formed on the inner wall of the processing container  101  in the dummy step and to prevent the chamber conditions from being disturbed. In the pretreatment of the film forming step, plasma processing may be performed instead of the annealing as long as the chamber conditions are not disturbed. 
     Specifically, the controller  106  controls each part of the processing apparatus  100  such that the pretreatment is performed under, for example, the following processing conditions. 
     &lt;Pretreatment of Film Forming Step&gt; 
     Microwave power: OFF 
     Internal pressure of processing container  101 : 0.01 to 10 Torr (2.66 to 1,333 Pa) 
     Processing gas: Ar/H 2 =0 to 3,000 sccm/l to 3,000 sccm 
     Temperature of wafer W: 300 to 700 degrees C. 
     Processing time: 5.0 seconds to 120 minutes 
     When the pretreatment is completed, the controller  106  starts supplying the Ar gas, which is a plasma-generating gas in the plasma CVD, from the gas introduction nozzles  123  (step S 12 : film formation). The controller  106  controls the microwave introduction device  105  to ignite the plasma (step S 13 : film formation). The controller  106  reduces the internal pressure of the processing container  101  to the second pressure (e.g., 0.05 Torr) (step S 14 : film formation). In addition, as in the dummy step, steps S 12  to S 14  are steps of stabilizing the gas, the pressure, and the plasma before the plasma CVD. 
     The controller  106  starts supplying the second carbon-containing gas (the C 2 H 2 /H 2  gas), which is a precursor of the plasma CVD, from the gas introduction nozzles  123  into the processing container  101  (step S 15 : film formation). These gas are excited and dissociated by the plasma, radicals from which ions and electrons are removed are supplied to the wafer W, and thus a carbon-containing film (a graphene film) is formed on the wafer W. In addition, the upper limit of the processing temperature during the film formation is set to be 900 degrees C., and the lower limit thereof is set to be about 300 degrees C. 
     Specifically, the controller  106  controls each part of the processing apparatus  100  such that the plasma CVD is performed under, for example, the following processing conditions. 
     &lt;Plasma CVD of Film Forming Step&gt; 
     Microwave power: 100 to 3,850 W (more preferably, 1,000 to 3,500 W) 
     Internal pressure of processing container  101 : 0.01 to 5 Torr (1.33 to 667 Pa) 
     Processing gas: C 2 H 2  gas=0.1 to 100 sccm
         H 2 =0.1 to 500 sccm   Ar=0.1 to 3,000 sccm       

     Temperature of wafer W: 300 to 700 degrees C. 
     Processing time: 5.0 seconds to 60 minutes 
     Descriptions will be made referring back to  FIG. 5 . When the film forming step is completed, the controller  106  unloads the wafer W from the processing container  101  (step S 4 ). The controller  106  determines whether or not the interior of the processing container  101  needs to be cleaned (step S 5 ). For example, the controller  106  determines whether or not the number of wafers W processed inside the processing container  101  after the previous cleaning reaches a predetermined value (e.g., one lot). When it is determined that it is not necessary to clean the interior of the processing container  101  (step S 5 : “No”), the controller  106  returns to step S 2 , places a subsequent wafer W, and performs the film forming step on the subsequent wafer W. 
     When it is determined that the interior of the processing container  101  needs to be cleaned (step S 5 : “Yes”), the controller  106  executes a cleaning step of cleaning the interior of the processing container  101  (step S 6 ). In the cleaning step, the dummy wafer is placed on the stage  102 , and the cleaning gas is supplied into the processing container  101  to clean the interior of the processing container  101 , 
     The controller  106  determines whether or not to end the film formation process following the cleaning step (step S 7 ). When it is determined that the film formation process is not completed (step S 7 : “No”), the controller  106  returns to step S 1  and executes the dummy step. On the other hand, when it is determined that that the film formation process is completed (step S 7 : “Yes”), the controller  106  ends the film formation process. 
     [Test Results] 
     A test was conducted to check in-plane film thickness distribution of wafers W subjected to the continuous formation of the graphene film as illustrated in the present embodiment.  FIG. 7  is a graph illustrating an example of in-plane film thickness distribution of wafers W subjected to the continuous film formation according to the present embodiment. In a graph  10  illustrated in  FIG. 7 , the in-plane film thickness distribution when graphene film formation process was performed on 10 sheets of wafers W is shown. As illustrated in the graph  10 , it can be seen that the film thicknesses are uniform from the first wafer (Run #1) to the tenth wafer (Run #10). Further, the variation in average film thickness value was 2.4% or less in 16. That is, in the present embodiment, it is possible to improve the film thickness uniformity between the wafers in the continuous film formation. 
       FIG. 8  is a view illustrating an example of an in-plane film thickness distribution of the wafers on which the continuous film formation was performed according to the present embodiment.  FIG. 8  illustrates an in-plane film thickness distribution of each of the wafers W from the first wafer (Run #1) to the tenth wafer (Run #10) in the present embodiment. As illustrated in  FIG. 8 , it can be seen that the same in-plane film thickness distribution is obtained from the first wafer (Run #1) to the tenth wafer (Run #10). That is, in the present embodiment, it is possible to improve the in-plane film thickness uniformity of each wafer W in the continuous film formation. In other words, it is possible to suppress non-uniformity in in-plane film thickness of each wafer W in the continuous film formation. That is, it is possible to significantly suppress the breakdown in the in-plane thickness distribution of film initially formed in the continuous film formation and to improve the stability of the in-plane film thickness distribution. 
     Comparative Example 
     In a comparative example performed in order to compare with the present embodiment, the continuous graphene film formation was performed without performing the dummy step. In the comparative example, in the film forming step, the pretreatment and the plasma CVD were performed under the following processing conditions, which are the same conditions as steps S 11  to S 15  illustrated in  FIG. 6 , except for the dummy and the processing time of the plasma CVD. 
     &lt;Pretreatment of Dummy Step in Comparative Example&gt;: None 
     &lt;Plasma CVD of Dummy Step in Comparative Example&gt;: None 
     &lt;Pretreatment of Film Forming Step in Comparative Example&gt; 
     Microwave power: OFF 
     Internal pressure of processing container  101 : 0.01 to 10 Torr (2.66 to 1,333 Pa) 
     Processing gas: Ar/H 2 =0 to 3,000 sccm/l to 3,000 sccm 
     Temperature of wafer W: 300 to 700 degrees C. 
     Processing time: 5.0 seconds to 120 minutes 
     &lt;Plasma CVD of Film Forming Step in Comparative Example&gt; 
     Microwave power: 100 to 3,850 W (more preferably, 1,000 to 3,500 W) 
     Internal pressure of processing container  101 : 0.01 to 5 Torr (1.33 to 667 Pa) 
     Processing gas: C 2 H 2  gas=0.1 to 100 sccm
         H 2 =0.1 to 500 sccm   Ar=0.1 to 3,000 sccm       

     Temperature of wafer W: 300 to 700 degrees C. 
     Processing time: 5.0 seconds to 60 minutes 
       FIG. 9  is a graph illustrating an example of in-plane film thickness distribution of wafers subjected to the continuous film formation in the comparative example. In a graph  20  illustrated in  FIG. 9 , the in-plane film thickness distribution when the graphene film formation process was performed on 10 sheets of wafers W is shown, as the comparative example. As illustrated in the graph  20 , it can be seen that the film thicknesses vary from the first wafer (Run #1) to the fifth wafer (Run #5) and thus the film thickness uniformity is not good between the wafers. On the other hand, it can be seen that the film thicknesses are uniform from the sixth wafer (Run #6) to the tenth wafer (Run #10). 
       FIG. 10  is a view illustrating an example of in-plane film thickness distribution of wafers subjected to the continuous film formation in the comparative example. In  FIG. 10 , the in-plane film thickness distribution of each wafer W from the first wafer (Run #1) to the tenth wafer (Run #10) is shown in the comparative example. As illustrated in  FIG. 10 , it can be seen that the in-plane film thickness uniformity is not good in the first sheet (Run #1) to the fifth sheet (Run #5). On the other hand, it can be seen that the similar in-plane film thickness distribution is obtained from the sixth wafer (Run #6) to the tenth wafer (Run #10). 
     As described above, according to the present embodiment, the processing apparatus  100  is a processing apparatus for forming a carbon-containing film using microwave plasma from a microwave source, and includes the processing container  101  configured to accommodate the substrate, the stage  102  on which the substrate (the wafer W) is placed inside the processing container  101 , and the controller  106 . The controller  106  executes the dummy step of generating plasma of the first carbon-containing gas inside the processing container  101  to perform the dummy process, the placement step of placing the substrate on the stage  102  inside the processing container  101 , and the film forming step of forming the carbon-containing film on the substrate using the plasma of the second carbon-containing gas. As a result, it is possible to improve the film thickness uniformity between the wafers in the continuous film formation. 
     According to the present embodiment, the controller  106  further executes the cleaning step of cleaning the interior of the processing container  101 , which is performed before the dummy step and after the film forming step. As a result, it is possible to further stabilize the chamber conditions in the dummy step. 
     In addition, according to the present embodiment, the cleaning step is executed in the state in which the dummy substrate is placed on the stage  102 . As a result, it is possible to protect the surface of the stage  102 . 
     According to the present embodiment, the dummy step includes performing the plasma processing using the hydrogen-containing gas at a first pressure, generating plasma of the hydrogen-and-argon-containing gas at the first pressure, and generating plasma of the first carbon-containing gas by reducing the internal pressure of the processing container  101  to a second pressure lower than the first pressure and starting the supply of the first carbon-containing gas. As a result, it is possible to stabilize the chamber conditions before the graphene film formation. 
     According to the present embodiment, the film forming step includes performing the annealing using the hydrogen-containing gas at a first pressure, generating plasma of the argon-containing gas at the first pressure, and generating plasma of the second carbon-containing gas by reducing the internal pressure of the processing container  101  to a second pressure lower than the first pressure and starting the supply of the second carbon-containing gas. As a result, it is possible to form the graphene film on the wafer W under stabilized chamber conditions. 
     According to the present embodiment, the first carbon-containing gas is the C 2 H 2  gas, and the second carbon-containing gas is a gas containing the C 2 H 2  gas and the H 2  gas. As a result, it is possible to form the graphene film as a carbon-containing film on the wafer W under stabilized chamber conditions. 
     According to the present embodiment, the processing time using the plasma of the first carbon-containing gas is longer than that using the plasma of the second carbon-containing gas. As a result, it is possible to stabilize the chamber conditions before the graphene film formation. 
     In addition, according to the present embodiment, the dummy step is performed in the state in which the dummy substrate is placed on the stage  102 . As a result, it is possible to prevent deposits from adhering to the surface of the stage  102  and to suppress the generation of particles. 
     In addition, according to the present embodiment, the dummy step is executed for each predetermined parameter (e.g., the number of processed wafers, a deposited film thickness, a processing time, and a plasma application time). As a result, it is possible to improve wafer processing capacity per hour. 
     It should be noted that the embodiments disclosed herein are exemplary in all respects and are not restrictive. The above-described embodiments may be omitted, replaced or modified in various forms without departing from the scope and spirit of the appended claims. 
     In the above-described embodiment, the pretreatment is performed using the plasma of the Ar/H 2  gas in the dummy step, but the present disclosure is not limited thereto. For example, the pretreatment may be performed by annealing using the Ar/H 2  gas. 
     In the above-described embodiment, in the dummy step, the Ar/H 2  gas is supplied to ignite plasma in the stabilization steps of the plasma CVD (steps S 12  to S 14 ), but the present disclosure is not limited thereto. For example, the Ar gas may be supplied to ignite the plasma. 
     In the above-described embodiment, the plasma CVD-based processing is performed in the dummy step, but the present disclosure is not limited thereto. For example, other processing such as annealing may be used as long as the processing can stabilize the chamber conditions. 
     In the above-described embodiment, the dummy step is executed in the state in which the dummy wafer is placed, but the present disclosure is not limited thereto. For example, by controlling the plasma generation region to be limited to the region directly below the ceiling wall portion  111 , the dummy step may be executed without placing the dummy wafer on the stage  102 . 
     In the above-described embodiment, the film formation process is started from the dummy step, but the present disclosure is not limited thereto. For example, a pre-coating step of pre-coating the inner wall of the processing container  101  with a carbon-containing film may be performed before the dummy step. 
     In the above-described embodiment, an aspect in which the graphene film is formed on the wafer W has been described, but the present disclosure is not limited thereto. For example, the present disclosure is also applicable to a case where an amorphous carbon film or a diamond-like carbon film is formed on the wafer W. 
     In the above-described embodiment, the processing apparatus  100  in which the processing container  101  is provided with the plurality of microwave radiation mechanisms  143  as microwave sources is used, but the present disclosure is not limited thereto. For example, a processing apparatus that radiates microwaves using a single planar slot antenna as a microwave source may be used. 
     In the above-described embodiment, the ceiling wall portion  111  is provided with the plurality of gas introduction nozzles  123 , but the present disclosure is not limited thereto. For example, gas may be supplied through a shower plate provided so as to partition upper and lower portions at a position above the stage inside the processing container. 
     According to the present disclosure, it is possible to improve the film thickness uniformity between wafers in continuous film formation. 
     While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosures. Indeed, the embodiments described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the disclosures. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosures.